Deep Laminae Research Articles

Anatomic, histologic, and ultrasound analyses of the dorsum of the hand for volumetric rejuvenation

Volumetric rejuvenation of the dorsum of the hand with fat grafting or injectable fillers has increased in popularity in recent years. It has become widely accepted that the dorsum of the hand contains three fatty laminae: superficial, intermediate, and deep laminae. The dorsal venous plexus and dorsal cutaneous nerves are known to reside in the dorsal intermediate lamina. However, the superficial vein and cutaneous nerve might not be located in the same layer of subcutaneous tissue, as is the case in other body regions. Eight hands were dissected in a layer-by-layer fashion from the skin to the extensor tendons. In another 13 hands from among 21 investigated cadavers, samples from the dorsum of the hand were harvested and stained using trichrome stains for histologic analysis. B-mode ultrasound was also performed for identifying structures of the dorsum of the hand. Anatomic dissection and histologic analysis of the dorsum of the hand revealed the presence of an unknown fascia in addition to the three known fascial layers. The additional fascia was located in the dorsal intermediate lamina and separated it into two compartments: one containing the dorsal venous plexus superficially and the other containing the dorsal cutaneous nerves deeply. Ultrasound showed corresponding structures including three hyperechoic fascial layers, three hypoechoic laminae, and additional hyperechoic fascia in dorsal intermediate lamina. Accurate anatomic knowledge of the dorsum of the hand will help practitioners determine the optimal and safe locations for performing fat grafting and injecting dermal fillers.

Anatomy of the Dorsum of the Foot and Its Relevance for Nonsurgical Cosmetic Procedures.

Operative procedures to enhance the aesthetic appearance of the feet are associated with risks. Minimally invasive procedures to volumize the dorsum of the foot are to this point not described. The present study investigates the safety and efficacy of such procedures in a retrospective clinical, anatomical, and ultrasound-based study. A total of 106 feet from 53 female patients (mean age, 64.1 ± 8.3 years) were investigated retrospectively after the injection of a commercially available calcium hydroxylapatite product using a single-entry proximal-to-distal fanning injection technique. Anatomical dissections in 20 fresh, nonembalmed feet from 10 human body donors (mean age, 83.1 ± 8.8 years) were dissected, and 20 feet from 10 healthy volunteers (mean age, 26.5 ± 6.2 years) were examined by ultrasound imaging to help guide conclusions. Aesthetic outcome after 3 months was graded by the patients as 4, connoting good improvement (range, 3 to 5). No allergic reactions or other types of adverse events were documented. The layered anatomy of the dorsum of the foot was confirmed by anatomical dissections and ultrasound imaging as follows: skin, dorsal superficial fatty layer, dorsal superficial fascia, dorsal intermediate fatty layer, superficial lamina of the dorsal deep fascia, dorsal deep fatty layer, and deep lamina of the dorsal deep fascia. Minimally invasive injections of soft-tissue filler in the dorsum of the foot can provide an alternate solution to enhance the aesthetic appearance of feet. The present study provides support for the safety and efficacy of volumizing procedures using a 22-gauge, 50-mm, blunt-tip cannula. Therapeutic, IV.

Intermediate Cervical Plexus Block in the Management of Persistent Postoperative Pain Post Carotid Endarterectomy: A Prospective, Randomized, Controlled, Clinical Trial

Background: The mechanisms of persistent postoperative pain (PPP) with neuropathic features after carotid endarterectomy (CEA) are multifaceted and are incompletely understood. Objectives: The aim of this research was to assess whether the ultrasound-guided (USG) intermediate cervical plexus block (ICPB) could provide better control of PPP and neuropathic disturbances (NPDs) after CEA than the USG superficial cervical plexus block (SCPB). Study Design: Prospective, randomized, controlled, clinical trial. Setting: This clinical trial was conducted at the SS Filippo and Nicola Academic Hospital of Avezzano (L’Aquila, Italy). Methods: Patients who were scheduled for primary CEA were chosen. In the experimental group, the USG-ICPB was performed unilaterally, at the level of the third cervical vertebra. The needle was inserted into the deep lamina of the deep fascia of the neck, between the posterior border of the middle scalene muscle and the anterior border of the posterior scalene muscle. Three milliliters saline solution was injected into the opening of the deep lamina, and 20 mL 0.375% levobupivacaine was injected. In the control group, the anesthetic target was located at the inferior border of the sternocleidomastoid muscle at the level of the third cervical vertebra. The needle was superficially inserted below the skin, and 2 to 3 mL saline solution was injected into the opening of the superficial lamina of the deep fascia of the neck. A total of 20 mL 0.375% isobaric levobupivacaine was subsequently injected. The primary outcome measure was the proportion of patients with PPP on movement and at rest 3 months after surgery. The secondary outcome measures were NPD assessment scores using the von Frey hair test and the Lindblom test, opioid and pregabalin consumption. Adverse effects were also recorded. Results: A total of 98 consecutive patients were enrolled and randomized to receive either a USGSCPB (control group, n = 49) or a USG-ICPB (experimental group, n = 49). The sensory blockade was longer in the experimental group. Three months after surgery, the proportions of patients with PPP on movement were significantly different between the experimental and control groups (33%, 95% confidence intervals [CI], 20%-47% vs. 71%, 95% CI, 57%-83%; P < 0.001), whereas there were no differences in the proportions of patients with pain at rest between groups (31%, 95% CI, 18%-45% vs. 49%, 95% CI, 34%-64%; P = 0.063). The proportions of patients with NPDs were not different between the groups, whereas the sizes of the areas of interest (cm2 ) were significantly different. Limitations: A limitation of this study is that we assessed NPDs for only 3 months using the von Frey hair test and the Lindblom test without additional instrumental techniques. Additionally, there are many risk factors for NPDs after CEA. For this reason, another limitation of this research is that we neglected to consider the relationship between the choice of anesthetic block and the presence of these risk factors.Conclusions: The USG-ICPB provided long-lasting analgesia during the postoperative period and might mitigate the development of NPDs, thereby decreasing the analgesic drug requirement. Key words: Carotid endarterectomy, intermediate cervical plexus block, myofascial planes of neck, neuropathic disturbances, persistent postoperative pain, superficial cervical plexus blocks, ultrasound guidance, vascular disease

Eosinophilic colitis in cancer patients.

e16500 Background: Eosinophilic colitis (EoC) is a rare form of eosinophilic gastrointestinal disease characterized by diffuse eosinophilic infiltration in the deep lamina propria and extensive crypt epithelial injury with apoptosis and crypt abscesses. The pathophysiology is still unclear and associated with many etiologies. We described the clinical characteristics of EoC in cancer patients. Methods: We retrospectively reviewed the pathology report of the colonic samples from endoscopy or surgical resection obtained between 01/2000 and 12/2018 at MD Anderson Cancer Center. The included cases had significant eosinophilia with key word description of “numerous”, “many” or “dominant” on the pathology. Clinical data were collected and analyzed. Results: A total of 41 cases were included based on the inclusion criteria with 34% men, with a median age of 60. 27% had NSAID use and 40% were smokers. One-fourth had co-existing autoimmune conditions. 78% had cancer diagnosis (hematologic at 41%, followed by genitourinary and gastrointestinal origin) with the rest carrying no cancer diagnosis. Half of the cases received chemotherapy with median duration of 180 days between chemotherapy to EoC onset. Common EoC symptoms included diarrhea, and abdominal pain which were present in 76% patients. Diarrhea was more prevalent in patients who received chemotherapy (85% vs 42%). Median duration of EoC symptoms was shorter in cancer patients (240 vs 30 days) and chemotherapy exposure (120 vs 30 days). Hospitalization for EoC was required in 15% cases. Most commonly administered treatment for EoC was immunosuppressants (22%). Normal colonoscopy was reported in 88% patients at the time of EoC diagnosis. All-cause mortality was 37% and was mostly related to underlying malignancy. Conclusions: The disease course of EoC in cancer patients on chemotherapy is not well defined. It appeared to be less severe than non-cancer patients, which raised the possibility of two separate subclasses of this disease entity. Cancer/chemotherapy related EoC could be a GI specific paraneoplastic manifestation, and behave differently from other etiology. [Table: see text]

The Missing Link in the Head Suspension of the Cat: A De Facto Nuchal Ligament

The nuchal ligament in quadrupedal mammals suspends the head from the trunk while the neck serves as a lever arm. Although well known as a deep, elastic “yellow” ligament”, especially in larger herbivores, it is either not mentioned or considered absent in cats. Based on biomechanical considerations, we hypothesized that the cat must have, if not an actual nuchal ligament, at least an analogous structure. We tested our hypothesis by micro‐dissecting specimens under a stereomicroscope fitted with a fiber‐optic ring‐light with a polarizing filter to visualize and trace individual muscle‐tendon fascicles and collagenous fiber bundles. We found that the cat actually has a de facto nuchal ligament that shares similarities with the nuchal ligament of humans instead of being of the yellow ligament variety. The de facto nuchal ligament of the cat originates on the spinous process of the first thoracic vertebra (or the preceding or following one) via the aponeurosis of the paired cervical trapezius muscles where it merges with the muscle fiber fascicles of the paired thoracic trapezius muscles. It continues cranially as two portions: (1) A superficial plait of interweaving tendon fiber fascicles, which inserts on the medial two‐thirds of the nuchal crest of the skull via the aponeurosis of the clavotrapezius muscle and is comparable to the dorsal raphe of the human nuchal ligament with its interweaving fibers; and (2) a deep, expansible but tenuous connective tissue lamina, which is loosely attached to the cervical vertebrae and is comparable to the midline fascial septum of the human nuchal ligament. The interweaving fibers of the superficial plait of the de facto nuchal ligament of the cat include myotendinous fibers of the right and left clavotrapezius and cervical trapezius muscles, with contributions from the cutaneous platysma muscle. While the superficial muscles creating the dorsal raphe of the human nuchal ligament are often described as crossing the dorsal midline and continuing on the opposite side as deeper muscles, we observed in the superficial plait of the de facto nuchal ligament of the cat that the tendon fiber fascicles of the superficial muscles actually join the endo‐, epi‐, and perimysium of the deeper muscles on the opposite side. These tendon fiber fascicles change orientation as the position of the clavotrapezius muscles change with movements of the limbs or the neck. The tendon fiber fascicles are transversely oriented when the head and neck are in the resting upright posture and the de facto nuchal ligament is relaxed, but are diagonally angled and pointing toward the head when the head and neck are lowered and the de facto nuchal ligament is stretched. Our findings suggest that the mechanisms of suspending the head and neck from the thorax while allowing the head to be lowered to feed or drink and then be returned to the upright position through resilience differ among mammals and encourage further investigations, particularly of mammals in which the nuchal ligament is thought to be absent, such as in the pig.Support or Funding InformationLSU Foundation to DGH

Mu and delta opioid receptors play opposite nociceptive and behavioural roles on nerve-injured mice.

Mu and delta opioid receptors(MOP, DOP) contribution to the manifestations of pathological pain is not understood. We used genetic approaches to investigate the opioid mechanisms modulating neuropathic pain and its comorbid manifestations. We generated conditional knockout mice with MOP or DOP deletion in sensoryNav1.8-positive neurons (Nav1.8), in GABAergic forebrain neurons (DLX5/6) orconstitutively (CMV). Mutant mice and wild-type littermates were subjected topartial sciatic nerve ligation (PSNL) or sham surgery and their nociception wascompared. Anxiety-, depressivelike behaviour and cognitive performance were also measured. Opioid receptor mRNA expression, microgliosis and astrocytosis were assessed in the dorsalroot ganglia (DRG) and/or the spinal cord (SC). Constitutive CMV-MOP knockouts after PSNL displayed reduced mechanical allodynia and enhanced heat hyperalgesia. This phenotype was accompanied by increased DOP expression in DRG and SC, and reduced microgliosis and astrocytosis in deep dorsal horn laminae. Conditional MOP knockouts and control mice developed similar hypersensitivity after PSNL, except for anenhanced heat hyperalgesia by DLX5/6-MOP male mice. Neuropathic pain-induced anxiety was aggravated in CMV-MOP and DLX5/6-MOP knockouts. Nerve-injured CMV-DOP mice showed increased mechanical allodynia, whereas Nav1.8-DOP and DLX5/8-DOP mice had partial nociceptive enhancement. CMV-DOP and DLX5/6-DOP mutants showed increased depressive-like behaviour after PSNL. MOP activity after nerve injury increased anxiety-like responses involving forebrain GABAergic neurons and enhanced mechanical pain sensitivity along with repression of DOP expression and spinal cord gliosis. In contrast, DOP shows a protective function limiting nociceptive and affective manifestations of neuropathic pain.

Neurochemical characterization of mouse dorsal root ganglion neurons expressing organic cation transporter 2.

Organic cation transporters (OCTs) are poly-specific carriers for endogenous and exogenous cationic compounds. These are widely distributed in the nervous system and mediate neuronal activities. As antineoplastic cationic drugs accumulate in the dorsal root ganglion (DRG), OCT function has been studied mainly in cultured DRG neurons. However, the histological distribution of OCTs in the DRG is unclear. This study investigated the localization of OCT2 (a member of OCTs) in mouse DRG neurons and determined their histochemical properties. OCT2 expression was found in about 20% of DRG neurons, which were small to medium size. OCT2-expressing neurons were labeled with markers for peptidergic nociceptive (substance P or calcitonin gene-related peptide) and tactile/proprioceptive (neurofilament 200 or tropomyosin receptor kinase B or C) neurons. OCT2 was also expressed in cholinergic DRG neurons identified by choline acetyltransferase promoter-derived Cre expression. In the spinal dorsal horn, OCT2 was distributed in superficial to deep laminae. OCT2 immunoreactivity was punctate in appearance and localized in the nerve terminals of sensory afferents with labeling of neurochemical markers. Our findings suggest that OCT2 as a low-affinity, high-capacity carrier may take up substrates including cationic neurotransmitters and drugs from the extracellular space around cell bodies in DRG neurons.

Resolving multisensory and attentional influences across cortical depth in sensory cortices.

In our environment, our senses are bombarded with a myriad of signals, only a subset of which is relevant for our goals. Using sub-millimeter-resolution fMRI at 7T, we resolved BOLD-response and activation patterns across cortical depth in early sensory cortices to auditory, visual and audiovisual stimuli under auditory or visual attention. In visual cortices, auditory stimulation induced widespread inhibition irrespective of attention, whereas auditory relative to visual attention suppressed mainly central visual field representations. In auditory cortices, visual stimulation suppressed activations, but amplified responses to concurrent auditory stimuli, in a patchy topography. Critically, multisensory interactions in auditory cortices were stronger in deeper laminae, while attentional influences were greatest at the surface. These distinct depth-dependent profiles suggest that multisensory and attentional mechanisms regulate sensory processing via partly distinct circuitries. Our findings are crucial for understanding how the brain regulates information flow across senses to interact with our complex multisensory world.

Effect of lutein on the acute inflammation-induced c-Fos expression of rat trigeminal spinal nucleus caudalis and C1 dorsal horn neurons.

Although lutein is known to inhibit chronic inflammation, its effect on acute inflammation-induced nociceptive processing in the trigeminal system remains to be determined. The aim of the present study was to investigate whether pretreatment with lutein attenuates acute inflammation-induced sensitization of nociceptive processing in rat spinal trigeminal nucleus caudalis (SpVc) and upper cervical (C1) dorsal horn neurons, via c-Fosimmunoreactivity. Mustard oil, a transient receptor potential ankyrin-1 channel agonist, was injected into the whisker pads to induce inflammation. Pretreatment of rats with lutein resulted in significant decreases in the inflammation-induced mean times of face grooming and the thickness of inflammation-induced edema in whisker pads relative to those features in inflamed rats (i.e., rats with no lutein pretreatment). In both the ipsilateral superficial and deep laminae of the SpVc and C1 dorsal horn, there were significantly larger numbers of c-Fos-positive neurons in inflamed rats than in naïve rats, and lutein pretreatment significantly decreased that number relative to inflamed rats. These results suggest that systemic administration of lutein attenuates acute inflammation-induced nocifensive behavior and augmented nociceptive processing of SpVc and C1 neurons that send stimulus localization and intensity information to higher pain centers. These findings support lutein as a potential therapeutic agent for use as an alternative, complementary medicine to attenuate, or even prevent, acute inflammatory pain.

Abstract 2338: Checkpoint inhibitor-induced colitis shares mucosal histopathological features with inflammatory bowel and graft-versus-host disease

Abstract Background: Checkpoint inhibitor-induced colitis (CIC) is a severe side-effect of immune-checkpoint inhibitors (ICI). Its pathophysiology is poorly understood, impairing improvement of prevention and treatment strategies. CD4+ and CD8+ T cells and CD68+ macrophages are thought to be critical in colitis development. Studies suggest that CIC is histopathologically similar to inflammatory bowel disease (IBD) and acute graft-versus-host disease (aGVHD) colitis. However, the histopathology of these entities has not been directly compared. We aimed to improve knowledge on CIC by performing a direct immunohistochemical comparison of CIC, IBD and aGVHD. Methods: Archival formalin fixed paraffin-embedded colon biopsies obtained during routine diagnostic procedures from consecutive, eligible, treatment-naïve patients with CIC, IBD and aGVHD (all n=20) were studied. Biopsies from patients without histopathological abnormalities served as controls (n=20). Immunohistochemical staining was performed for CD4+ and CD8+ T cells and CD68+ macrophages. In each biopsy 3 mucosal areas with highest immune cell density were selected for cell counting. The number of cells/hotspot were classified as 0-10, 10-50, 50-100, 100-150 and >150. Next, the distribution of these cells was studied and compared between patient groups. We used descriptive statistics to depict and compare cell counts and infiltration patterns among patient groups. Results: In CIC higher CD4+ and CD8+ T cell density (100-150 cells/hotspot in most patients) was observed compared to IBD, aGVHD and controls (50-100 cells/hotspot in most patients in each group). In contrast to controls, some IBD (12%) and aGVHD (15%) patients had a CD4+ T cell count of 100-150 cells/hotspot and some IBD (20%) and aGVHD (21%) patients had a CD8+ T cell count of 100-150 cells/hotspot. CIC, IBD aGVHD and controls shared a similar CD68+ macrophage count (50-100 cells/hotspot in most patients in each group). During cell counting we noted that cells infiltrated the superficial (subepithelium) and deep (lamina propria and muscularis mucosae) layers of the mucosa with either a scattered or patchy distribution. We recognized 4 distribution patterns: A) superficial diffuse, deep scattered/patchy; B) superficial scattered/patchy, deep diffuse; C) superficial and deep diffuse; D) superficial and deep scattered/patchy. The most prevalent infiltration pattern of CD4+ T cells was D in CIC patients (74%), C in IBD patients (47%), B in aGVHD patients (54%) and A in control patients (83%). The most prevalent infiltration pattern of CD8+ T cells was D in CIC (45%), and A in IBD (85%), aGVHD (63%) and all control patients. In most patients, CD68+ macrophages occurred in pattern A (56% of CIC, 58% of IBD, 59% of aGVHD, 100% of controls). Conclusion: CIC has a distinct immunohistopathological pattern that shares key elements with both IBD and aGVHD. Citation Format: Sara Hone Lopez, Gursah Kats-Ugurlu, Liesbeth De Vries, Marco De Groot, Marijn Visschedijk, Mathilde Jalving, Jacco de Haan. Checkpoint inhibitor-induced colitis shares mucosal histopathological features with inflammatory bowel and graft-versus-host disease [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2338.

Nail Anatomy, Nail Psoriasis, and Nail Extensor Enthesitis Theory: What Is the Link?

The concept of the nail unit as a musculoskeletal appendage has become popular in the dermatological and rheumatological literature. However, an exact knowledge of the characteristics of mesenchyme surrounding the nail such as the composition of the collagen and elastic fibers and their arrangement is fundamental before one can propose a constitutive model. To the best of my knowledge, there is no study in the literature concerning the elastic network of the ligamentous connective tissue of the base of the distal phalanx. This study by means of elastic stains demonstrates that the so-called superficial, deep, and lateral laminae of the extensor tendon correspond to 3 different microanatomic structures: the nail dermis and its fibrous root, the subcutaneous proximal nail fold, and the periosteum. The complex fascial and adipose connective tissue of the proximal nail fold surrounds the matrical dermis and could viewed as a kind of suspensory system for the proximal nail unit. Such suspensory system protects the nail matrix epithelium from the biomechanical strain of the extensor mechanism. Near the ulnar and radial edge of the base of the phalanx, focal interconnections between the fibrous root of the apex of the matrix and the periosteum through a fascia-like structure are visible. In its most lateral zone, the matrical horns lie on a thick dermis connected to the interosseous ligament. Such lateral laminar system serves as anchoring ropes for the vault of the nail plate. The nail-extensor enthesitis theory relies on an oversimplified anatomy because the nail unit is an epidermal appendage with a specialized connection with the lateral periosteum, but not a musculoskeletal appendage. Finally, I would like to emphasize, the practical importance of recognizing the matrical hypoderm. In nail surgery, the interface between the matrical nail dermis and its submatrical loose connective tissue is potentially a new, relatively superficial, surgical cleaving plane, beside the classical deep surgical procedure usually extending to the periosteum. Recognition of this additional cleaving plane leads to an optimal nail tangential biopsy.

Expression of cholecystokinin by neurons in mouse spinal dorsal horn.

Excitatory interneurons account for the majority of dorsal horn neurons, and are required for perception of normal and pathological pain. We have identified largely non‐overlapping populations in laminae I‐III, based on expression of substance P, gastrin‐releasing peptide, neurokinin B, and neurotensin. Cholecystokinin (CCK) is expressed by many dorsal horn neurons, particularly in the deeper laminae. Here, we have used immunocytochemistry and in situ hybridization to characterize the CCK cells. We show that they account for ~7% of excitatory neurons in laminae I‐II, but between a third and a quarter of those in lamina III. They are largely separate from the neurokinin B, neurotensin, and gastrin‐releasing peptide populations, but show limited overlap with the substance P cells. Laminae II‐III neurons with protein kinase Cγ (PKCγ) have been implicated in mechanical allodynia following nerve injury, and we found that around 50% of CCK cells were PKCγ‐immunoreactive. Neurotensin is also expressed by PKCγ cells, and among neurons with moderate to high levels of PKCγ, ~85% expressed CCK or neurotensin. A recent transcriptomic study identified mRNA for thyrotropin‐releasing hormone in a specific subpopulation of CCK neurons, and we show that these account for half of the CCK/PKCγ cells. These findings indicate that the CCK cells are distinct from other excitatory interneuron populations that we have defined. They also show that PKCγ cells can be assigned to different classes based on neuropeptide expression, and it will be important to determine the differential contribution of these classes to neuropathic allodynia.

Lamina-specific population encoding of cutaneous signals in the spinal dorsal horn using multi-electrode arrays.

Key points Traditional, widely used in vivo electrophysiological techniques for the investigation of spinal processing of somatosensory information fail to account for the diverse functions of each lamina.To overcome this oversimplification, we have used multi‐electrode arrays, in vivo, to simultaneously record neuronal activity across all laminae of the spinal dorsal horn.Multi‐electrode arrays are sensitive enough to detect lamina‐ and region‐specific encoding of different subtypes of afferent fibres and to detect short‐lived changes in synaptic plasticity as measured by the application of cutaneous electrical stimulation of varying intensity and frequency.Differential encoding of innocuous and noxious thermal and mechanical stimuli were also detected across the laminae with the technique, as were the effects of the application of capsaicin.This new approach to the study of the dorsal spinal cord produces significantly more information per experiment, permitting accelerated research whilst also permitting the effects of pharmacological tools to modulate network responses. The dorsal horn (DH) of the spinal cord is a complex laminar structure integrating peripheral signals into the central nervous system. Spinal somatosensory processing is commonly measured electrophysiologically in vivo by recording the activity of individual wide‐dynamic‐range neurons in the deep DH and extrapolating their behaviour to all cells in every lamina. This fails to account for the specialized processes that occur in each lamina and the considerable heterogeneity in cellular phenotype within and between laminae. Here we overcome this oversimplification by employing linear multi‐electrode arrays (MEAs) in the DH of anaesthetized rats to simultaneously measure activity across all laminae. The MEAs, comprising 16 channels, were inserted into the lumbar dorsal horn and peripheral neurons activated electrically via transcutaneous electrodes and ethologically with von Frey hairs (vFHs) or an aluminium heating block. Ascending electrical stimuli showed fibre thresholds with distinct dorsoventral innervation profiles. Wind up was observed across the DH during the C‐fibre and post‐discharge latencies following 0.5 Hz stimulation. Intrathecal application of morphine (5 ng/50 μl) significantly reduced Aδ‐ and C‐fibre‐evoked activity in deep and superficial DH. Light vFHs (≤10 g) predominantly activated intermediate and deep laminae whereas noxious vFHs (26 g) also activated the superficial laminae. Noxious heat (55°C) induced significantly greater activity in the superficial and deep laminae than the innocuous control (30°C). The application of these arrays produced the first description of the processing of innocuous and noxious stimuli throughout the intact DH.

Lamina-specific cortical dynamics in human visual and sensorimotor cortices.

Distinct anatomical and spectral channels are thought to play specialized roles in the communication within cortical networks. While activity in the alpha and beta frequency range (7 - 40 Hz) is thought to predominantly originate from infragranular cortical layers conveying feedback-related information, activity in the gamma range (>40 Hz) dominates in supragranular layers communicating feedforward signals. We leveraged high precision MEG to test this proposal, directly and non-invasively, in human participants performing visually cued actions. We found that visual alpha mapped onto deep cortical laminae, whereas visual gamma predominantly occurred more superficially. This lamina-specificity was echoed in movement-related sensorimotor beta and gamma activity. These lamina-specific pre- and post- movement changes in sensorimotor beta and gamma activity suggest a more complex functional role than the proposed feedback and feedforward communication in sensory cortex. Distinct frequency channels thus operate in a lamina-specific manner across cortex, but may fulfill distinct functional roles in sensory and motor processes.

Eosinophils in the gastrointestinal tract: how much is normal?

The normal density of eosinophils in the digestive mucosa of children has been rarely addressed despite being important to provide baseline counts for the diagnosis of eosinophilic gastrointestinal disorders (EGID). Histopathological criteria for EGID remain undefined and there has been little consistency of results in different populations. We aimed to establish the eosinophil density of the normal digestive mucosa in a paediatric population submitted to endoscopic procedures with normal histological features. Biopsies from endoscopies of 33 patients were evaluated. Quantification of eosinophils was performed manually. Review of the pathology reports confirmed absence of abnormality in the biopsy specimens. Counts were expressed in eosinophils per high power field and per mm2. Oesophagus (n = 33): eosinophils were uniformly absent in all biopsies. Stomach: counting was performed, separately, in the superficial and deep lamina propria of the fundus (n = 13), corpus (n = 13) and antrum (n = 16). Mean eosinophilic density was higher in the deep lamina propria. Small intestine: eosinophil counts revealed 18.1 ± 17.0, 14.4 ± 12.0, and 51.5 ± 35.3 in the lamina propria of the bulb (n = 13), D2 (n = 13), and ileum (n = 16), respectively. Large intestine: the highest peak count was observed in the caecum (125 mm2; n = 16) with a mean of 51.8 ± 33.5. The eosinophil counts were lower in the ascending (n = 16; 40.9 ± 27.4), transverse (n = 14; 34.3 ± 21.9), descending (n = 15; 40.0 ± 26.6), and sigmoid (n = 17; 25.8 ± 17.8) colon and in the rectum (n = 17; 13.9 ± 10.1). These data provide a baseline count and distribution of eosinophils in the gastrointestinal tract of paediatric patients with normal mucosa, thus expanding the scarce published data.

Bone marrow transplant-associated thrombotic microangiopathy without peripheral blood schistocytes: a case report and review of the literature

BackgroundBone marrow transplant-associated thrombotic microangiopathy (TA-TMA) is a relatively frequent but under-recognized and under-treated hematopoietic stem cell transplant (HSCT) complication that leads to significant post-transplant morbidity and mortality. Classic TMA-defining laboratory abnormalities appear at different times in the course of TA-TMA development, with schistocytes often appearing later in the disease course. In some severe TMA cases, schistocytes may be absent due to increased endothelial permeability. Unfortunately, many clinicians continue to perceive the presence of schistocytes as an absolute requirement for TA-TMA diagnosis, which leads to delayed recognition and treatment of this potentially fatal transplant complication.MethodsPatient chart review and PubMed literature search using the term, “transplant-associated thrombotic microangiopathy”.Case presentationA 54-year-old male IgG kappa multiple myeloma underwent a reduced intensity allogeneic HSCT from a 9/10 HLA-matched unrelated donor after conditioning with fludarabine and melphalan. On day + 27, the patient developed acute kidney injury followed by repeated episodes of diarrhea and gastrointestinal bleeding attributed to graft versus host disease (GVHD) and cytomegalovirus (CMV) colitis. Repeated colonic biopsies suggested CMV infection and GVHD. Despite appropriate treatment with antiviral therapy and immunosuppressants, the patient’s condition continued to deteriorate. He experienced concomitant anemia and thrombocytopenia as well as elevated lactate dehydrogenase and low haptoglobin levels, but a TA-TMA diagnosis was not made due to an absence of schistocytes on peripheral smear. The patient expired secondary to uncontrolled gastrointestinal bleeding. A post-mortem analysis of the resection specimen revealed extensive TMA involving numerous arteries and arterioles in the ileal and colonic submucosa as well as in the muscularis propria and deep lamina propria of the mucosa.ConclusionsTA-TMA can occur in the absence of peripheral blood schistocytes. Our experience underscores the importance of considering the diagnosis of intestinal TA-TMA in patients with refractory post-transplant diarrhea and GI bleeding, even if all classic features are not present.

Low- and high-threshold primary afferent inputs to spinal lamina III antenna-type neurons.

The dorsal horn of the spinal cord (laminae I-VI) processes diverse modalities of nociceptive and nonnociceptive sensory information. Antenna-type neurons with cell bodies located in lamina III and large dendritic trees extending from the superficial lamina I to deep lamina IV are best shaped for the integration of a wide variety of inputs arising from primary afferent fibers and intrinsic spinal circuitries. Although the somatodendritic morphology, the hallmark of antenna neurons, has been well studied, little is still known about the axon structure and basic physiological properties of these cells. Here, we did whole-cell recordings in a rat (P9-P12) spinal cord preparation with attached dorsal roots to examine the axon course, intrinsic firing properties, and primary afferent inputs of antenna cells. Nine antenna cells were identified from a large sample of biocytin-filled lamina III neurons (n = 46). Axon of antenna cells showed intensive branching in laminae III-IV and, in half of the cases, issued dorsally directed collaterals reaching lamina I. Antenna cells exhibited tonic and rhythmic firing patterns; single spikes were followed by hyperpolarization or depolarization. The neurons received monosynaptic inputs from the low-threshold Aβ afferents, Aδ afferents, as well as from the high-threshold Aδ, and C afferents. When selectively activated, C-fiber-driven monosynaptic and polysynaptic excitatory postsynaptic potentials were sufficiently strong to evoke firing in the neurons. Thus, lamina III antenna neurons integrate low-threshold and nociceptive high-threshold primary afferent inputs and can function as wide dynamic range neurons able to directly connect deep dorsal horn with the major nociceptive projection area lamina I.

Proximal attachment of long head of biceps brachii to the bicipital tubercle of scapula and its functional significance

IntroductionLesions affecting the tendon of Long Head of Biceps brachii (LHB) are among the more frequent causes of pain and disability in the region of shoulder joint. Shoulder arthroscopy has shown that there is dual attachment of LHB to the Supraglenoid tubercle (SGT) and glenoid labrum, but the origin from the bony prominence on upper part of dorsal surface of neck of scapula has not been described in the literature reviewed. This bony elevation has been named as “Bicipital Tubercle (BT)”. What is astonishing is the fact that such a prominent BT has been either missed or ignored by earlier workers. MethodsDuring the dissection of the shoulder joint, the tendon of LHB could be separated into superficial and deeper laminae. The fibres of the superficial lamina could be traced to BT in approximately 80% cases. ResultsIn 70% of specimens LHB was seen to join the posterior labrum; in 20% the anterior labrum and in the remaining to both the labrum. In 57% of right and 65% of the left scapulae the BT was very prominent ConclusionThe efficiency of action of LHB is enhanced by its getting a firm attachment to the bicipital tubercle (BT). Thus in man the origin of the tendon of LHB has shifted from only the SGT to SGT plus labrum, and further has got an additional attachment to BT. This attachment to the BT seems to have been overlooked and demands its inclusion in all the future studies.

Development and evolution of tooth renewal in neoselachian sharks as a model for transformation in chondrichthyan dentitions.

A defining feature of dentitions in modern sharks and rays is the regulated pattern order that generates multiple replacement teeth. These are arranged in labio-lingual files of replacement teeth that form in sequential time order both along the jaw and within successively initiated teeth in a deep dental lamina. Two distinct adult dentitions have been described: alternate, in which timing of new teeth alternates between two adjacent files, each erupting separately, and the other arranged as single files, where teeth of each file are timed to erupt together, in some taxa facilitating similarly timed teeth to join to form a cutting blade. Both are dependent on spatiotemporally regulated formation of new teeth. The adult Angel shark Squatina (Squalomorphii) exemplifies a single file dentition, but we obtained new data on the developmental order of teeth in the files of Squatina embryos, showing alternate timing of tooth initiation. This was based on micro-CT scans revealing that the earliest mineralised teeth at the jaw margin and their replacements in file pairs (odd and even jaw positions) alternate in their initiation timing. Along with Squatina, new observations from other squalomorphs such as Hexanchus and Chlamydoselachus, together with representatives of the sister group Galeomorphii, have established that the alternate tooth pattern (initiation time and replacement order) characterises the embryonic dentition of extant sharks; however, this can change in adults. These character states were plotted onto a recent phylogeny, demonstrating that the Squalomorphii show considerable plasticity of dental development. We propose a developmental-evolutionary model to allow change from the alternate to a single file alignment of replacement teeth. This establishes new dental morphologies in adult sharks from inherited alternate order.

Non-invasive laminar inference with MEG: Comparison of methods and source inversion algorithms

Magnetoencephalography (MEG) is a direct measure of neuronal current flow; its anatomical resolution is therefore not constrained by physiology but rather by data quality and the models used to explain these data. Recent simulation work has shown that it is possible to distinguish between signals arising in the deep and superficial cortical laminae given accurate knowledge of these surfaces with respect to the MEG sensors. This previous work has focused around a single inversion scheme (multiple sparse priors) and a single global parametric fit metric (free energy). In this paper we use several different source inversion algorithms and both local and global, as well as parametric and non-parametric fit metrics in order to demonstrate the robustness of the discrimination between layers. We find that only algorithms with some sparsity constraint can successfully be used to make laminar discrimination. Importantly, local t-statistics, global cross-validation and free energy all provide robust and mutually corroborating metrics of fit. We show that discrimination accuracy is affected by patch size estimates, cortical surface features, and lead field strength, which suggests several possible future improvements to this technique. This study demonstrates the possibility of determining the laminar origin of MEG sensor activity, and thus directly testing theories of human cognition that involve laminar- and frequency-specific mechanisms. This possibility can now be achieved using recent developments in high precision MEG, most notably the use of subject-specific head-casts, which allow for significant increases in data quality and therefore anatomically precise MEG recordings. SectionAnalysis methods. ClassificationsSource localization: inverse problem; Source localization: other.