Peripheral Neural Tissue Research Articles

Evaluation of the Expansion and Neuronal Differentiation Potency of Cultured Olfactory Epithelium Progenitor Cells from a Rat Model of Depression.

Olfactory impairment has been reported in patients with depression and in rodent models of depression. Olfactory epithelium (OE) is the only peripheral neural tissue connected to the brain that has the potential for self-renewal. We hypothesized the olfactory deficit during depression may be related to the dysfunction of OE progenitor cells. The aim of the present study was therefore to evaluate the expansion and neuronal differentiation potency of cultured OE progenitor cells obtained from a rat model of depression. Rats were exposed to chronic unpredictable mild stress procedures to establish a depressive-like state. Depressive-like behavior and olfactory sensing function were then evaluated and compared with control rats. Primary OE progenitor cells were cultured in vitro. The proliferation potency and survival of OE progenitor cells were assessed by 5-Ethynyl-2'-deoxyuridine staining and Cell Counting Kit-8 (CCK8), respectively, while cellular apoptosis was measured by flow cytometry. The neuronal differentiation potency of OE progenitor cells was evaluated by measurement of the protein and mRNA level of β-3 tubulin, a marker of neural cells. mRNA expression associated with neural stemness was examined by quantitative reverse transcription polymerase chain reaction (RT-PCR). Depressive-like rats showed decreased olfactory function. OE progenitor cells from depressive-like rats showed reduced cell proliferation/survival and neuronal differentiation potency. Moreover, OE progenitor cells from depressive-like rats showed decreased expression of mRNA related to neural stemness. These results indicate the impaired function of OE progenitor cells may contribute to the olfactory deficit observed during depression. The OE may therefore provide a window for the study of depression.

PARIN5, a Novel Thrombin Receptor Antagonist Modulates a Streptozotocin Mice Model for Diabetic Encephalopathy.

Diabetic encephalopathy (DE) is an inflammation-associated diabetes mellitus (DM) complication. Inflammation and coagulation are linked and are both potentially modulated by inhibiting the thrombin cellular protease-activated receptor 1 (PAR1). Our aim was to study whether coagulation pathway modulation affects DE. Diabetic C57BL/6 mice were treated with PARIN5, a novel PAR1 modulator. Behavioral changes in the open field and novel object recognition tests, serum neurofilament (NfL) levels and thrombin activity in central and peripheral nervous system tissue (CNS and PNS, respectively), brain mRNA expression of tumor necrosis factor α (TNF-α), Factor X (FX), prothrombin, and PAR1 were assessed. Subtle behavioral changes were detected in diabetic mice. These were accompanied by an increase in serum NfL, an increase in central and peripheral neural tissue thrombin activity, and TNF-α, FX, and prothrombin brain intrinsic mRNA expression. Systemic treatment with PARIN5 prevented the appearance of behavioral changes, normalized serum NfL and prevented the increase in peripheral but not central thrombin activity. PARIN5 treatment prevented the elevation of both TNF-α and FX but significantly elevated prothrombin expression. PARIN5 treatment prevents behavioral and neural damage in the DE model, suggesting it for future clinical research.

Bio-inspired engineering of a perfusion culture platform for guided three-dimensional nerve cell growth and differentiation.

Collagen provides a promising environment for 3D nerve cell culture; however, the function of perfusion culture and cell-growth guidance is difficult to integrate into such an environment to promote cell growth. In this paper, we develop a bio-inspired design method for constructing a perfusion culture platform for guided nerve cell growth and differentiation in collagen. Based on the anatomical structure of peripheral neural tissue, a biomimetic porous structure (BPS) is fabricated by two-photon polymerization of IP-Visio. The micro-capillary effect is then utilized to facilitate the self-assembly of cell encapsulated collagen into the BPS. 3D perfusion culture can be rapidly implemented by inserting the cell-filled BPS into a pipette tip connected with syringe pumps. Furthermore, we investigate the nerve cell behavior in the BPS. 7-channel aligned cellular structures surrounded with a Schwann cell layer can be stably formed after a long-time perfusion culture. Differentiation of PC12 cells and mouse neural stem cells shows 3D neurite outgrowth alignment and elongation in collagen. The calcium activities of differentiated PC12 cells are visualized for confirming the preliminary formation of cell function. These results demonstrate that the proposed bio-inspired 3D cell culture platform with the advantages of miniaturization, structure complexity and perfusion has great potential for future application in the study of nerve regeneration and drug screening.

Short‐ and Long‐Term Effects of Dietary Supplementation with Fish Oil on Inflammatory Pain in Rats

Introduction Dietary supplementation with fish oil is promising as a complementary therapy for inflammatory pain. However, further studies are needed to support its therapeutic potential. For example, the antinociceptive effect of fish oil is widely suggested to be dependent on decreased prostaglandin E2 (PGE2) synthesis, but no previous study has investigated if it affects PGE2-induced nociceptive response. Similarly, beneficial long-term effects on inflammatory response are related to early exposure to fish oil, however, whether these effects include decreased inflammatory pain throughout life is not known. Objective The aim of this study was to investigate the short- and long-term effects of fish oil on inflammatory pain. Methods Dietary fish oil supplementation was performed through two protocols: in adult rats, during 20 days, or in dams, during pregnancy and lactation, with tests performed in adult offspring. The hyperalgesic response induced by carrageenan and its final mediators PGE2 and norepinephrine was used to model inflammatory pain. Results The findings demonstrated for the first time that dietary fish oil (1) decreases the hyperalgesia induced by carrageenan; (2) but not that induced by its final mediator PGE2 and norepinephrine; (3) increase omega-3 polyunsaturated fatty acids in peripheral neural tissue; and (4) attenuates inflammatory pain in individuals exposed to fish oil during pre-natal life and lactation. Conclusion Together, these findings support that fish oil decreases inflammatory pain either when consumed during adult life or during prenatal development. Future studies should confirm the therapeutic potential of fish oil in humans, which is essential for the development of public policies to encourage a fish oil richer diet.

Negative α-synuclein pathology in the submandibular gland of patients carrying PRKN pathogenic variants

IntroductionAlpha-synuclein (AS) pathology in the peripheral nervous tissue is a potential pathological biomarker in Parkinson disease (PD). Several studies reported the excellent specificity of the AS pathology of the submandibular gland (SMG) biopsy in PD. PRKN pathogenic variant is one of the major genetic causes of young-onset PD without Lewy pathology in the brain. In this study, we evaluated peripheral AS pathology in the SMG biopsy of patients with PRKN pathogenic variants. MethodsWe enrolled three young-onset PD patients with PRKN pathogenic variants. Two patients were compound heterozygous for trans-exon 3 and 4 deletions and one patient was heterozygous for an exon 2 duplication. We obtained two submandibular gland tissues with core needle biopsy (18G). The neural structures were identified using neurofilament (NF) immunostaining and the neural tissue in the adjacent section were stained with 129 phophorylated α-synuclein (pAS) antibody.Results: pAS staining in the SMG was negative in all cases with the PRKN pathogenic variants. ConclusionsOur data may support the high specificity of the AS pathology of SMG in α-synuclein associated parkinsonism. Future studies evaluating peripheral neural tissue including the SMG in the elderly healthy population are required to validate the role of peripheral AS pathology as a biomarker in PD.

Neuromas at the castration site in geldings

BackgroundInguinal pain, unexplained hind limb lameness, back pain or behavioural problems in geldings could be attributable to painful neuromas that develop as a consequence of crushing and severing the testicular nerves during castration. The presence of neuroma in this anatomical location has never been reported, hence the knowledge of possible clinical relevance is limited. The aim of this study was to histologically investigate the testicular nerves at the castration site in geldings for the presence of neuromas. Proximal spermatic cord remnants were collected from 20 geldings admitted to routine post mortem examination for various reasons. The time of castration was unknown, but it had not been performed during the last year. Spermatic cord specimens were immersed in 10% formalin, trimmed, dehydrated, embedded in paraffin, sectioned and stained with haematoxylin and eosin (HE) for light microscopy. Identification of nerve tissue was done by immuno-localization of nerve specific enolase (NSE).ResultsNeuromas were found in 21 spermatic cords from 13 geldings and were bilateral in eight of the horses. The neuromas consisted of areas with small groups of non-neoplastic proliferations of peripheral neural tissue. The tissue included neurofilaments and Schwann cells, intermingled or surrounded with, epineural, perineural and endoneural fibrous tissue. The neural tissue immunostained positive with NSE.ConclusionsThis study showed neuromas of the remnant testicular nerves at the site of castration. Further studies are required to establish if these neuromas in the castration site are painful and if certain castration methods promote their formation. Future studies should also investigate the clinical consequence of these neuromas for the individual horse.

Sertolioma in a Canadian Husky: Relationship between Tumor, Hormones, Neurons and Skin

Background: Sertolioma is a slow-growing, non-invasive, firm and nodular tumor, malignant in 10% to 22% of cases and with low metastatic potential. Old age and cryptorchidism increase up to 26 times its chances of development and associates it with malignancy. Paraneoplastic syndrome, shown in 20% to 30% of the animals, is due to the aromatization of testosterone or the direct production of estrogen by tumor cells, leading to signs of feminization and bone marrow aplasia. The objective of this article is to report a case of sertolioma in a dog with dermatological characteristic symptoms, but presenting an unusual aggressive behavior, both completely reverted after castration.Case: A 9-year-old, uncastrated, aggressive and uncontrollable Canadian Husky dog was treated at the Institutional Veterinary Hospital with parapenial volume increase and generalized alopecia. A scrotal testis of reduced size and flaccid consistency and a mass in a parapenial region of 11 x 7.5 x 8 cm in diameter, with a cystic contour, adhered to the abdominal musculature and painless to palpation were detected. Cytology of the parapenial mass presented an image compatible with seminoma or sertolioma, and the preputial smear revealed a predominance of superficial cells. Ultrasound examination showed a heterogeneous inguinal mass, with expansive cystic area, compatible with mass in retained inguinal testis. Therapeutic course consisted of bilateral orchiectomy. Ectopic testis was firm to the cut, had whitish to yellowish coloration and was surrounded by a tunica containing 200 mL of serosanguinolent liquid. The histology of the mass revealed sertolioma-compatible cell characteristics, with cell proliferation circumvented by fibrous connective tissue forming poorly delimited lobes, moderate polymorphism with elongated cells, arranged in a palisade at the periphery of the lobes, vacuolated eosinophilic cytoplasm and vesiculous round nuclei. The unretained testicle revealed signs of atrophy. After surgery the patient showed a progressive improvement of the dermatological symptoms. However, what most caught the attention was the change in aggressive behavior, and fifteen days after surgery the animal was extremely docile and easily restrained during the clinical examination.Discussion: Hyperesthyrogenism due to sertolioma results from: 1) direct synthesis of estrogen by neoplastic tumor cells 2) increase in metabolism by central conversion (testicular cells) or peripheral hepatocytes, myocytes, adipocytes, hair follicles and neural tissue) androgens into estrogen through the aromatization of testosterone and 3) androgen and estrogen rate imbalance. Testosterone is considered responsible for the aggressive behavior in males, evidenced by the decrease of this behavior when the testicles are removed, and by the reinstallation of this behavior when the hormonal replacement is done. However, research on mice showed that estrogen-sensitive regulatory pathways also play a role in promoting this behavior. Although practically undetectable in male circulation, its presence stems from in vivo synthesis from the aromatization of testosterone, and it is this local estrogen, peripherally synthesized in the brain, that would be responsible for the control of dimorphic behaviors in males. The importance of the estrogen signaling pathway in aggression has also been reported in a study in knockout mice for estrogen receptors, in which males rarely exhibited aggressiveness. Such information is sufficient to support the hypothesis that the disappearance of the aggressiveness of the reported animal was obtained due to castration and correction of hyperestrogenism, showing the importance of including it as an important cause of aggressive behavior in uncastrated male dogs.

Methods for fabrication and evaluation of a 3D microengineered model of myelinated peripheral nerve

Objective. The cost and low success rates of the neurological drug development pipeline have diverted the pharmaceutical industry to ‘nerve-on-a-chip’ systems as preclinical models to streamline drug development. We present a novel micro-engineered 3D hydrogel platform for the culture of myelinated embryonic peripheral neural tissue to serve as an effective in vitro model for electrophysiological and histological analysis that could be adopted for preclinical testing. Approach. Dorsal root ganglions (DRG) from 15 d old embryonic rats were cultured in 3D hydrogel platforms. The interaction between Schwann cells (SC) and neurons during axonal development and regeneration affects the direction of growth and the synthesis of myelin sheaths. Induction of myelination was performed with two approaches: the addition of exogenous SC and promoting migration of endogenous SC. Main results. Histological analysis of the preparation utilizing exogenous SC showed aligned, highly fasciculated axonal growth with noticeable myelin sheaths around axons. Separately, electrophysiological testing of the preparation utilizing endogenous SC showed increased amplitude of the compound action potential and nerve conduction velocity in the presence of ascorbic acid (AA). Significance. This platform has immense potential to be a useful and translatable in vitro testing tool for drug discovery and myelination studies.

Soft Tissue Sarcomas - Series of Cases in One Surgical Department

Abstract Introduction. Soft tissue sarcomas (STS) are a heterogeneous group of tumors with over 80 different subtypes that account for approximately 1-2% of adult malignancies. Primary sarcomas arise from a variety of soft tissues and bone, and include fibrous connective, fat, and smooth, or striated muscle, vascular, peripheral neural and visceral tissue. With difficulties in establishing cell origin and pathogenesis, this condition lacks an effective and durable therapy with no predictive biomarkers and rapid diagnosis. Materials and methods. We reviewed the cases of 21 patients treated in our clinic for soft tissue sarcoma over a 20-year period (1999-2018). We extracted the following information from each patient’s medical record: disease status at presentation, histological diagnosis, American Joint Committee on Cancer staging, surgical procedure, oncological outcome, length of hospitalization, and follow-up information. Results. All 21 patients (14 males and 7 females, aged between 19 and 88 years) underwent surgery and total excision with safety margins was performed with histopathological confirmation stating the tumor type and subtype. Some samples required immunohistochemistry for subtype differentiation. Chondrosarcoma and myosarcoma were the most common (5 patients). 8 patients presented local recurrence and metastatic disease with 6 cases receiving adjuvant chemotherapy. Only one patient presented for the 5-year follow-up. Conclusions. STS are a rare group of tumors with poor outcome with surgical treatment being represented by total excision. We chose to present our clinic’s experience to highlight the need for post-operative therapy advancements and to raise awareness on the difficulties in managing these cases.

A reduction in DNA damage in neural tissue and peripheral blood of old mice treated with caffeine

ABSTRACTStudies on caffeine consumption have shown a negative correlation with development of some diseases with subsequent beneficial manifestations. Our aim was to assess the effects of caffeine on peripheral blood and neural tissue DNA in young adult and aged mice. Male Swiss mice (age 2–3 or 16–18 months, respectively) were treated with a caffeine solution (0.3 g/l) for 4 weeks, while controls received water. After the treatments, blood and hippocampal cells (for a comet assay) and femurs (for a micronucleus [MN] test) were collected. The comet assay of peripheral blood and hippocampal cells demonstrated no significant differences between caffeine-treated and control young adult mice in terms of DNA damage index (DI) and frequency. In contrast, when comparing young adult with aged animals, significant differences were observed in DNA damage in blood and hippocampal cells. The differences between aged animals (with or without caffeine) consisted of a significant decrease in DNA DI in the group that received caffeine. In the MN test, an increase in frequency of micronucleated polychromatic (PCE) erythrocytes was noted in aged animals that received water compared to young adult mice. In addition, comparing treated with control aged murine groups, a decrease in frequency of MN was found in PCE erythrocytes of caffeine-treated mice. Chronic caffeine consumption was neither genotoxic nor mutagenic at the dose tested; however, it appears that caffeine actually protected mice from genotoxicity and mutagenicity, consequences attributed to aging.

Myelinated 3D neural culture platform as a physiological model of diabetic peripheral neuropathy

Event Abstract Back to Event Myelinated 3D neural culture platform as a physiological model of diabetic peripheral neuropathy Ashwin Sivakumar1, Reed Gioe1 and Michael Moore1, 2 1 Tulane University, Department of Biomedical Engineering, United States 2 Tulane University, Department of Neuroscience, United States Introduction: We present a microengineered 3D hydrogel platform for culture of myelinated embryonic peripheral neural tissue as shown in Figure 1. This novel in-vitro platform enables morphological and physiological metrics analogous to clinical nerve fiber density and nerve conduction tests. We demonstrate the feasibility of this model system for studying peripheral neuropathy caused by glucose-induced neurotoxicity, the most common form of neuropathy. Figure 1: Microengineered myelinated neural fiber tract 3D architecture resembling native peripheral nerve anatomy. Materials and Methods: Dorsal root ganglia (DRG) from embryonic day 15 rats were grown over a period of 4 weeks in a dual hydrogel system consisting of a methacrylated heparin gel in a polyethylene glycol micro-mold. The dual hydrogel system served to constrain the axon growth to be polarized with high density, fasciculation and myelination. The DRG’s were subject to a three-stage media regimen including ascorbic acid (AA) in the final stage to induce Schwann Cell myelination. The myelinated cultures were subjected to 60mM concentrations of the D-glucose in media over a period of 48 hours to simulate diabetic neuropathy. The control cultures were exposed to a 25mM D-glucose concentration. Electrophysiological field recordings were taken with and without the exposure of high glucose, and changes in the compound action potentials in the field recording were observed and compared to the control. Results and Discussion: Compound action potentials show little or no synaptic input, increased delay and decreased amplitude with higher glucose concentration exposure as shown in Figure 2. The higher glucose concentration is thought to trigger the sorbitol pathway and induce oxidative stress in the neurons of the DRG, leading to apoptosis and axonal degeneration. Figure 2: Average traces representing compound action potentials recorded with and without high glucose treatment. The change in amplitude and latency are also quantified as bar plots. (n=10, * = p<0.05 and ***=p<0.001) Conclusion: Microengineered myelinated neural fiber tracts have morphology, physiology and, toxicity response analogous to a peripheral nerve. The platform could be used as an in-vitro model for neuropathy studies and drug development. Funding provided by Tulane University

Intravenous AAV9 efficiently transduces myenteric neurons in neonate and juvenile mice.

Gene therapies for neurological diseases with autonomic or gastrointestinal involvement may require global gene expression. Gastrointestinal complications are often associated with Parkinson's disease and autism. Lewy bodies, a pathological hallmark of Parkinson's brains, are routinely identified in the neurons of the enteric nervous system (ENS) following colon biopsies from patients. The ENS is the intrinsic nervous system of the gut, and is responsible for coordinating the secretory and motor functions of the gastrointestinal tract. ENS dysfunction can cause severe patient discomfort, malnourishment, or even death as in intestinal pseudo-obstruction (Ogilvie syndrome). Importantly, ENS transduction following systemic vector administration has not been thoroughly evaluated. Here we show that systemic injection of AAV9 into neonate or juvenile mice results in transduction of 25–57% of ENS myenteric neurons. Transgene expression was prominent in choline acetyltransferase positive cells, but not within vasoactive intestinal peptide or neuronal nitric oxide synthase cells, suggesting a bias for cells involved in excitatory signaling. AAV9 transduction in enteric glia is very low compared to CNS astrocytes. Enteric glial transduction was enhanced by using a glial specific promoter. Furthermore, we show that AAV8 results in comparable transduction in neonatal mice to AAV9 though AAV1, 5, and 6 are less efficient. These data demonstrate that systemic AAV9 has high affinity for peripheral neural tissue and is useful for future therapeutic development and basic studies of the ENS.

Two-photon polymerization-generated and micromolding-replicated 3D scaffolds for peripheral neural tissue engineering applications

In this study, we explore the production of well-defined macroscopic scaffolds with two-photon polymerization (2PP) and their use as neural tissue engineering scaffolds. We also demonstrate that these 3D scaffolds can be replicated via soft lithography, which increases production efficiency. Photopolymerizable polylactic acid (PLA) was used to produce scaffolds by 2PP and soft lithography. We assessed the biocompatibility of these scaffolds using an SH-SY5Y human neuronal cell line and primary cultured rat Schwann cells (of direct relevance to the repair of nerve injuries). A Comet assay with SH-SY5Y human neuronal cells revealed minimal DNA damage after washing the photocured material for 7 days in ethanol. Additionally, thin films and 3D scaffolds of the photocured PLA sustained a high degree of Schwann cell purity (99%), enabled proliferation over 7 days and provided a suitable substrate for supporting Schwann cell adhesion such that bi-polar and tri-polar morphologies were observed. Evidence of orthogonally aligned and organized actin thin filaments and the formation of focal contacts were observed for the majority of Schwann cells. In summary, this work supports the use of PLA as a suitable material for supporting Schwann cell growth and in turn use of 3D soft lithography for the synthesis of neural scaffolds in nerve repair.

Neuroma traumático palatino: presentación de un caso

Traumatic neuroma is a reactive tumor of the peripheral neural tissue produced after an injury. This entity appears in the oral cavity usually after a trauma or surgical procedures such as tooth extraction. We report a case of traumatic neuroma in the palate of a 71-year-old man and review the most important clinicopathological features of this tumor.

Fatal infection withBorrelia burgdorferiby involvement of the cardiac conducting system

The cardiac conducting system of a patient with fatal cardiac involvement byB. burgdorferi showed necrosis of associated muscle fibers in the sinoatrial node with lymphoplasmacytic infiltrate and focal edema. Lymphocytic infiltrate was also found around the atrioventricular node and in the penetrating bundle and branching bundle. Fibrosis in the left bundle branch apparently resulted in nearly complete discontinuation of the fibers. Peripheral neural and muscular tissue also showed signs of inflammation. Spirochetes were demonstrated in the branching bundle and between the muscular fibers of the right atrium. Peripheral neural and muscular tissue showed signs of disseminated Lyme borreliosis.

Calretinin Expression in Unicystic Ameloblastoma: An Aid in Differential Diagnosis

Calretinin is a 29 kDa calcium-binding protein, which is widely expressed in the central and peripheral neural tissue. It has also been demonstrated in odontogenic epithelium during odontogenesis and in neoplastic odontogenic tissues. The lining epithelium of eight cases of unicystic ameloblastoma, six cases of dentigerous cyst, six cases of odontogenic keratocyst, reclassified as keratocystic odontogenic tumor (KCOT), and four cases of solid/multicystic ameloblastoma was examined for the expression of calretinin. No positive staining was observed in any of the dentigerous cysts and keratocystic odontogenic tumor linings. In comparison, coarse dark brown staining was seen in the stellate reticulum of solid multicystic ameloblastoma and more superficial epithelial layers of unicystic ameloblastoma. In conclusion, we have highlighted calretinin to be a specific immunohistochemical marker for neoplastic ameloblastic tissue that can be used as an important diagnostic aid in the differential diagnosis of unicystic ameloblastoma and cystic odontogenic lesions.

Problems in Design of Neuro-controlled Prosthetic Devices

One of the most promising ways of constructing modern prosthetic control systems would be to use electrical control signals recorded from peripheral neural tissue. In this work the construction of such systems is analyzed in order to upgrade modern technical devices and methods that are used to design these systems. The requirements for technical devices and methods used to record and process neural signals and rules are also considered. The efficiency of the systems and methods is estimated and described. A generalized structure of neural prosthetic control systems and a way of preprocessing control signals to provide more efficient information transfer are suggested.

Is Phosphatidylcholine Harmful to the Peripheral Neural Tissue? An Experimental Study in Rats

Subcutaneous phosphatidylcholine (PC) injection has become a popular technique for treating localized fat accumulation. Some clinical studies reported minor local soft tissue complications, such as ecchymosis, edema, and pain. However, there are no data on how PC affects the peripheral nervous tissue. To investigate the local effect of PC on the peripheral nervous tissue of rats. Twenty adult Lewis rats weighing between 200 and 300 g were divided into 2 experimental groups (n=10). In group 1, animals received an intrafascicular injection of 0.1 mL PC (Lipostabil 250 mg/5 mL) with a 30-gauge needle into the left posterior tibial nerve. In group 2, as a negative control group, 0.1 mL normal saline was injected intrafascicularly respectively. After the operation, rats were evaluated on days 7, 14, and 21 with walking track analysis. On day 21, all the animals were sacrificed and the left tibial nerves were taken for histologic study. Light and electron microscopic studies, along with morphometric analysis, were performed. According to the tibial nerve indices, there were no signs of nerve damage observed in either of the groups, and there was no statistical difference between the groups (P> .05). The nerves that received PC and saline injections could not be distinguished grossly and appeared similar to segments of the nerve that did not come in contact with either solution. The number and diameter of fibers, the thickness of the myelin, and the percentage of neural tissue were comparable with normal controls. According to these analyses, there were no statistical differences between the 2 groups (P> .05). This study demonstrates that in a rat model, even direct intraneural injection of PC causes no damage. This information should encourage people to consider broader applications of PC.

Ultrasound guidance with contrast enhancement leads to successful brachial plexus block

INTRODUCTION: Ultrasound imaging facilitates brachial plexus localization1 and is known to improve the quality of blocks and onset times2. MATERIAL AND METHODS: Local IRB approval was obtained for this study. A total of 30 patients scheduled for upper limb surgery under regional block were prospectively recruited in this study and evaluated in terms of efficacy, ease of insertion, onset times and primary and secondary catheter failure. Infraclavicular brachial plexus localization, needle and subsequent catheter placement was done posterior to the axillary artery under ultrasound guidance with peripheral nerve stimulation assistance. Needle and catheter tip was identified using hand agitated 5% dextrose with Doppler color flow on the ultrasound. Onset of block was defined as complete loss of motor and sensory function in the brachial plexus distribution and was evaluated over a 30-minute period. Postoperatively, after the block had worn off, catheter stimulation was attempted and block was re-established under ultrasound imaging. RESULTS: Mean time to plexus location was 6.5 min, catheter insertion was 4 minutes and onset of complete motor and sensory block was 19.7 minutes. There were no incomplete blocks. Axillary nerve was blocked in 100% of patients. None of the patients required supplementation or / and GA due to incomplete block. Post operatively, in 87% of patients brachial plexus could be stimulated. All patients had sensory block and complete analgesia. In 95.7% of patients spread of drug via the catheter tip could be visualized by hand agitated local anesthetic agent as seen by Doppler on ultrasound. DISCUSSION: Secondary catheter failure is the main reason why continuous post operative analgesia is incomplete. Contrast enhancement in evaluation of peripheral neural tissue has not been evaluated though it was originally reported in 1968 as a clinical method3. We used ultrasound guidance for location of brachial plexus and insertion of the needle in the infraclavicular area . This has been earlier demonstrated7. We inserted the catheter and demonstrated the position of catheter tip by hand agitated 5% dextrose by Doppler flow in all patients and achieved 100% success rate for the initial block. On local anesthetic re-injection, we were able to see spread of the drug under Doppler ultrasound amounting to analgesia in 100% of patients post operatively. Till date, there is no report of use of ultrasound for positioning of catheter in the infraclavicular area and its confirmation by agitated dextrose / drug with Doppler color flow.

Pheasant ataxia: a new condition in pheasant poults

Between 1995 and 1997 a neurological condition in pheasant poults from 24 sites in England and Scotland was investigated. Affected birds showed varying degrees of ataxia and incoordinated movements and, in severe cases, recumbency, but generally remained alert with their heads held upright. The condition characteristically affected poults from seven weeks of age and the incidence on any one site was low. No significant bacteria were isolated consistently from brain tissue. The condition was characterised histologically by a non-suppurative meningoencephalitis, in which lesions were found predominantly in the cerebellum in 61 of 81 samples examined (75.3 per cent). A non-suppurative myelitis was recorded in 16 of 20 spinal cords examined. No lesions were recorded in peripheral neural tissue and lesions were rare in other tissues. The condition appeared not to have been recorded previously in pheasants. A viral aetiology was suspected but Newcastle disease virus was not involved.