Peripheral Plexus Research Articles

Sensory cells and the organization of the peripheral nervous system of the siboglinid Oligobrachia haakonmosbiensis Smirnov, 2000

BackgroundThe nervous system of siboglinids has been studied mainly in Osedax and some Vestimentifera, while data in Frenulata – one of the four pogonophoran main branches – is still fragmentary. In most of the studies, the focus is almost always on the central nervous system, while the peripheral nervous system has traditionally received little attention. In contrast to other annelids, the structure and diversity of sensory structures in siboglinids are still quite undescribed. Meanwhile, the peripheral nervous system, as well as sensory elements, are extremely evolutionarily labile, and information about their organization is of high importance to understand lifestyles and behavior as well as main trends that lead siboglinids to their peculiar organization.ResultsThe structure of the peripheric nervous system, sensory elements, and neuromuscular relationships of Oligobrachia haakonmosbiensis were studied using both scanning electron and confocal laser microscopy. A significant number of monociliary sensory cells, as well as sensory complexes located diffusely in the epithelium of the whole body were revealed. The latter include the cephalic tentacles, sensory cells accumulations along the dorsal furrow and ciliary band, areas of the openings of the tubiparous glands, and papillae. The oval ciliary spot located on the cephalic lobe at the base of the tentacles can also be regarded as a sensory organ. Most of the detected sensory cells show immunoreactivity to substance P and/or acetylated α-tubulin. FMRFamide- and serotonin-like immunoreactivity are manifested by neurons that mainly innervate tentacles, muscles, body wall epithelium, skin glands, tubiparous glands, and papillae. In the larva of O. haakonmosbiensis, monociliary sensory elements were revealed in the region of the apical organ, along the body, and on the pygidium.ConclusionsThe diversity of sensory structures in O. haakonmosbiensis comprises epidermal solitary sensory cells, sensory spots around tubiparous glands openings, and putative sensory organs such as cephalic tentacles, an oval ciliary spot on the cephalic lobe, the dorsal furrow, and papillae. Sensory structures associated with papillae and tubiparous glands play presumable mechanosensory functions and are associated with regulation of tube building as well as anchorage of the worm inside the tube. Sensory structures of the dorsal furrow are presumably engaged in the regulation of reproductive behavior. An overall low level of morphological differentiation of O. haakonmosbiensis peripheral nervous system is not typical even for annelids with the intraepithelial nervous system. This can be considered as a plesiomorphic feature of its peripheral plexus’s organization, or as evidence for the neotenic origin of Siboglinidae.

Lack of WWC2 Protein Leads to Aberrant Angiogenesis in Postnatal Mice.

The WWC protein family is an upstream regulator of the Hippo signalling pathway that is involved in many cellular processes. We examined the effect of an endothelium-specific WWC1 and/or WWC2 knock-out on ocular angiogenesis. Knock-outs were induced in C57BL/6 mice at the age of one day (P1) and evaluated at P6 (postnatal mice) or induced at the age of five weeks and evaluated at three months of age (adult mice). We analysed morphology of retinal vasculature in retinal flat mounts. In addition, in vivo imaging and functional testing by electroretinography were performed in adult mice. Adult WWC1/2 double knock-out mice differed neither functionally nor morphologically from the control group. In contrast, the retinas of the postnatal WWC knock-out mice showed a hyperproliferative phenotype with significantly enlarged areas of sprouting angiogenesis and a higher number of tip cells. The branching and end points in the peripheral plexus were significantly increased compared to the control group. The deletion of the WWC2 gene was decisive for these effects; while knocking out WWC1 showed no significant differences. The results hint strongly that WWC2 is an essential regulator of ocular angiogenesis in mice. As an activator of the Hippo signalling pathway, it prevents excessive proliferation during physiological angiogenesis. In adult animals, WWC proteins do not seem to be important for the maintenance of the mature vascular plexus.

Ефективність програми відновлення функції верхньої кінцівки при травматичних та компресійно-ішемічних ураженнях периферичних нервів та плечового сплетення

Purpose: to determine the effectiveness of the developed program for the restoration of upper limb function in traumatic and compression-ischemic injuries of the peripheral nerves. Material & Methods: the study involved 173 patients who were divided into 2 main rehabilitation groups: group I – patients with acute traumatic damage to the peripheral nerve or plexus (132 people), group II – patients with compression-ischemic (tunnel) neuropathies and plexopathies (41 people). The study was conducted on the basis of the Institute of Neurosurgery acad. A. P. Romodanova of the National Academy of Medical Sciences of Ukraine” (2015–2018) and on the basis of neurological departments No. 1 and No. 2 of the Kiev City Clinical Hospital No. 4 (2017–2019). To assess impaired motor function of the nerve and sensitivity, a 6-point scale was used according to the method of R. B. Zachary, W. Holmes, N. Millesi. The Boston Questionnaire (Boston Carpal Tunnel Questionnaire) was used to assess the severity of symptoms, activity, and participation in daily life. Results: during the initial examination, we found that in the majority of patients of the 1st rehabilitation group, motor disorders on a 6-point scale were at the level of M1-M2 in 27,3% and 31,8% of individuals, respectively, and M3 in 15,9% of patients. In patients of the rehabilitation group II, the indicators of motor disorders were not so pronounced: patients with impaired motor function at the level of M2-M3 prevailed (34,1% and 24,4% of patients, respectively). According to the scale of functional disorders of the Boston questionnaire, the patients with the studied groups experienced the greatest difficulties when bathing and putting on clothes – 17,4%, doing homework – 13,6% of people, fastening buttons on clothes – 15,2%. In patients of the rehabilitation group II, approximately the same results were observed. In the main group, we used the program of rehabilitation measures that we developed, in the comparison group, the program that is used in the hospital for this category of patients. The therapy lasted 3 months. Upon repeated examination in patients of the main І rehabilitation group, motor disorders decreased under the influence of physical therapy, which were used in them. In the main group, a greater number of patients (12,3%) showed normal strength in the affected limb (M5), in the control group this indicator was lower (7,5%). Movements with overcoming the weight of the limb (M3) and movements with overcoming the resistance (M4) were observed in 24,6% and 30,8% of patients in the main group, which significantly exceeds similar indicators of the control group. Conclusions: as shown by the results of studies, physical therapy and occupational therapy in the complex treatment of people with traumatic and compression-ischemic neuropathies of the upper limb contributed to a more intensive restoration of arm functions and increased results of motor therapy. The following rehabilitation measures are most effective for this category of patients: kinesiotherapy, taping, massage, physiotherapy, mechanotherapy and hydrotherapy.

Neuropathic pain: mechanisms of development, principles of diagnostics and treatment

Neuropathic pain is a pain caused by a disease or focal damage to the somatosensory nervous system. The prevalence of chronic pain with neuropathic features in different countries is estimated at 7–10 %. Damages to the nervous system can occur at the level of peripheral nerves, plexus and dorsal roots (peripheral neuropathic pain) or spinal cord and brain (central neuropathic pain). Neuropathic pain is based on pathological activation of pain pathways. Neuropathic pain occurs with diabetic polyneuropathy more often than with all polyneuropathies of another etiology. Hyperglycemia is the major cause of chronic diabetes mellitus and its progression. Since the cause of pain can rarely be cured, treatment is usually symptomatic. Neuropathic pain is generally poorly controlled by analgesics. NB management is started with conservative pharmacotherapy before applying invasive analgesia. Although there are many drugs that can be used in patients with DPN, monotherapy can not always stop pain syndrome. In addition, the patient may not tolerate the full therapeutic dose of the drug. All this dictates the need for combination therapy.

Local effects of acupuncture on the median and ulnar nerves in patients with carpal tunnel syndrome: a pilot mechanistic study protocol

BackgroundWhile acupuncture’s mechanism of action is not fully understood, there is consensus that the nervous system plays a key role in processing its effects. This research is based on the structural theory of acupuncture, which aims to correlate the location of acupuncture points to peripheral nerves, spinal segments, and spinal plexuses. This mechanistic study explores the close anatomical association between the Pericardium meridian/median nerve and the Heart meridian/ulnar nerve in an attempt to produce electrophysiologic data measuring acupuncture’s direct, nerve-specific effect on the underlying nerves. Specifically, the purpose of this research is to use nerve conduction studies (NCSs) and quantitative sensory testing (QST) to assess for any local, nerve-specific effect of three acupuncture modalities on two anatomically distinct nerves in the forearm — the median and ulnar nerves — in subjects with carpal tunnel syndrome (CTS). The choice of CTS as an injured nerve model allows for comparisons between the response in an injured nerve (median) to that of a healthy one (ulnar).MethodsSubjects with mild to moderate CTS will be randomized to three intervention groups: manual acupuncture and low- and high-frequency electroacupuncture. Each subject will receive two treatments, 1 week apart, to points in the forearm, which overlay the median nerve (Pericardium meridian) or the ulnar nerve (Heart meridian). Acupuncture will be administered in random order to minimize learning effects in sensory testing. During Week 1, baseline NCS and QST (vibration and cold detection thresholds) will be obtained in both nerve territories, followed by acupuncture and post-acupuncture NCS and QST measurements in both nerve territories. During Week 2, repeat baseline QST and NCS measurements will be obtained, followed by acupuncture to points overlying the nerve not treated in Week 1, followed by post-acupuncture NCS and QST measurements in both nerve distributions.DiscussionThis works aims to capture and characterize the local effects of acupuncture on an underlying nerve and compare them to those on a neighboring nerve. Quantifying acupuncture’s effects using physiologic parameters and discrete values could standardize treatment regimens and help assess their therapeutic effect.Trial registrationClinicalTrials.gov, NCT03036657. Registered on 30 January 2017. Retrospectively registered.

Neuroanatomy of Hyalinella punctata: Common patterns and new characters in phylactolaemate bryozoans.

Studies on the bryozoan adult nervous system employing immunocytochemical techniques and confocal laser scanning microscopy are scarce. To gain a better view into the structure and evolution of the nervous system of the Phylactolaemata, the earliest extant branch and sister taxon to the remaining Bryozoa, this work aims to characterize the nervous system of Hyalinella punctata with immunocytochemical techniques and confocal laser scanning microscopy. The cerebral ganglion is located between the anus and the pharynx and contains a lumen. Two ganglionic horns and a circum-oral nerve ring emanate from the cerebral ganglion. The pharynx is innervated by a diffuse neural plexus with two prominent neurite bundles. The caecum is innervated by longitudinal neurite bundles and a peripheral plexus. The intestine is characterized by longitudinal and circular neurite bundles, mostly near the anus. Novel putative sensory cells were found in the foregut and intestine. The tentacle sheath is innervated by a diffuse neural plexus, which emanates from several neurite bundles from the cerebral ganglion, but also parts of the pharyngeal plexus. There are six tentacle neurite bundles of intertentacular origin. The retractor muscles are innervated by two thin neurite bundles. Several characters are described herein for the first time in Phylactolaemata: Longitudinal neurite bundles and a peripheral plexus of the caecum, putative sensory structures of the gut, retractor muscle innervation, specific duplicature band neurite bundles. The tentacle innervation differs from previous descriptions of phylactolaemates regarding the origin of the three abfrontal neurite bundles. In general, most organ systems are innervated by a diffuse plexus in phylactolaemates as opposed to gymnolaemates. In contrast to the Gymnolaemata, representatives of Phylactolaemata show a higher number of tentacle nerves. Although the plesiomorphic condition for zooidal features among bryozoans remains unclear, having a diffuse nerve plexus may represent an ancestral feature for freshwater bryozoans.

Complicaciones neurológicas del cáncer

AetiopathegenesisTumour action can be due to direct damage to the nervous structures of the cerebral parenchyma or to the peripheral nerves or their respective casings, either due primary tumour growth or, most commonly (92%), due to cerebral metastasis. In more than 30% the origin will be a breast cancer, and around 10% will be of haematological, pulmonary or gynaecological origin. Indirect involvement due to vascular damage or inflammatory cytokines might precede tumour appearance (paraneoplastic syndrome) or be secondary to treatment (chemo- or radiotherapy-induced neurotoxicity). Clinical pictureOn the one hand, intracranial, medullar, lepatomeningeal (meningeal carcinomatosis) and neural (peripheral plexus and nerves) metastatic involvement are considered, and on the other, non-metastatic complications including alterations of consciousness level or delirium, neurotoxic effects of chemo- and radiotherapy and those deriving from diagnostic and surgical procedures, vascular disorders and infections, and sympathetic hyperactivity. DiagnosisImaging techniques with high-contrast capacity should include magnetic resonance imaging, electromyography and electroencephalography and nuclear medicine techniques. TreatmentTreatment of neuropathy symptoms and non-metastatic disorders is usually susceptible to improvement, at least in part. However this does not apply to the management of metastasis, which even today continues to have a poor prognosis in general.

9. IOM of peripheral nerves, plexus, roots and spinal cord

In the laboratory, motor conduction studies are recorded using surface electrodes. Supramaximal stimulation can synchronously depolarize all the functioning motor axons with minimal temporal dispersion. A well-placed surface electrode captures a large, compound muscle action potential (CMAP). Needle electromyography (EMG) can effectively record only a restricted field of a few cubic millimeters. Near field recording makes possible motor unit analysis and acquisition of pathologic Surface electrodes (including short “EEG” needles) often fail to record intraoperative neurotonics. Intraoperative navigation about nerves depends on reliable neurotonic surveillance and acquisition of amply summated CMAPs after stimulation. Robust conduction studies (and neurotonic recording) can usually be performed if a sufficient length of bare wire (a partially denuded monopolar EMG electrodes) can be implanted intramuscularly. Peripheral motor axons will depolarize if struck with sufficient energy. For a given mass, end velocity 2 of the nerve impact determines (1) whether individual axons will fire and (2) how many axons will fire (i.e., the amplitude of the recorded submaximal nerve action potential). Acutely (or chronically) injured nerves may lose the ability to accommodate; that is, they keep firing repetitively well after the stimulus. Train neurotonics (“A trains” per Romstock, 2000) are likely explained by the “breakdown” of accommodation.

Variants of Neurotization in Injuries of Brachial Plexus and Nerves of Upper Extremity

The most commonly used variants of neurotization on the upper extremity in various injuries of peripheral nerves or brachial plexus and results of their application are presented. Pledge of successful neurotization is thorough knowledge of topographic anatomy of peripheral nerve branches, skills in precision surgical technique and adequate postoperative rehabilitation.

The Role Of CD11b+CX3CR1+ Cells In Neovascularization

There is solid evidence that myelo-monocytic cells actively contribute to angiogeneic processes. However, the specific subpopulations of myelo-monocytic cells participating in vascularization and their precise underlying mechanisms have not been well identified. Recently it has been reported that CX3CR1, a receptor for fractalkine (CX3CL1; Fkn), is highly induced at injury sites and CX3CR1 positive cells have an active role for angiogenesis in a mouse wound healing model. Therefore, we evaluated neovascularization activities of CD11b+CX3CR1+ cells during recovery of blood perfusion in a hind-limb ischemic injury mouse model and also identified their activities during the process of angiogenic sprouting in the retina of early postnatal Sprague-Dawley (SD) rat. Ischemic injuries were induced in C57BL/6 mice by femoral artery dissections. Single-cell suspensions were made from ischemic muscles using collagenase and dispase digestion. Isolated CD11b+CX3CR1+ cells and CD11b-CX3CR1- cells from ischemic muscle (5x105 cells/mouse) were injected into ischemic muscles 2 days after femoral artery dissections. Laser Doppler Perfusion (LDP) indexes were assessed as an indicator for blood perfusion. In order to block the functions of CX3CR1 and Fkn, either anti-CX3CR1 or anti-Fkn neutralizing antibody (Ab) were injected into ischemic muscles. To determine whether CX3CR1 has a role in actively growing retinal vessels, intravitreal microinjections were done with anti-CX3CR1 Ab at postnatal 2 days (P2) SD rat. P5 retinas treated with neutralizing anti-CX3CR1 Ab at P2 were used. CD11b+CX3CR1+ cells were positive for CD45 and F4/80, monocyte/macrophage marker. CD11b+CX3CR1+ cells accumulated at the injured muscles in C57BL/6 mice. We tested for contribution of CD11b+CX3CR1+ cells to neovascularization in the injury sites by injecting ischemic muscle-derived CD11b+CX3CR1+ cells or CD11b-CX3CR1- cells into the adductor muscles of C57BL/6 mice. CD11b+CX3CR1+ cells enhanced blood perfusion when compared to CD11b-CX3CR1- cells (78.0±3.2% vs 39.0±0.3% of LDP indexes at day 28, p<0.01). Both neutralizing Abs to CX3CR1 and Fkn significantly reduced blood perfusion resulting in decreased LDP indexes of 25.9±4.9% and 29.4±4.6% compared to those of the non-ischemic limbs (p<0.01). When CX3CR1 function was blocked with anti-CX3CR1-neutralizing Ab, CD11b+CX3CR1+cells were completely eliminated and any vessel-like structures were not observed in the ischemic muscles. By staining of isolectin for P5 retina, well-organized primitive vascular plexus was observed. However, blocking the function of CX3CR1 resulted in formation of peripheral plexus that was more highly interconnected. Additionally, vessels coalesced to form a syncytium in some areas. Thus, CD11b+CX3CR1+ cells accumulate at sites of ischemic injury and enhance recovery of blood flow via new vascular structure formation. Furthermore, CX3CR1 acts to prevent overexuberant vascular growth and promotes formation of well-differentiated vascular network.In summary, CD11b+CX3CR1+ cells are a newly identified subset of myelomonocytic cells for vessel formation, capable of regulating vascular formation. CD11b+CX3CR1+ cells may be an attractive clinical tool to accelerate tissue vasculature development in various ischemic diseases. Disclosures:No relevant conflicts of interest to declare.

Magnetic resonance neurography for the evaluation of peripheral nerve, brachial plexus, and nerve root disorders

Magnetic resonance neurography for the evaluation of peripheral nerve, brachial plexus, and nerve root disorders

Long current impulses may be required for nerve stimulation in patients with ischemic pain

To report on the efficacy of peripheral plexus catheters in the treatment of ischemic pain in spite of nerve stimulation with long current impulses.Two patients with severe neuropathic ischemic foot pain are described. A 56-yr-old man with diabetes, renal failure, and autonomic neuropathy presented with severe ischemic foot pain. Opioids produced excess sedation and hypotension. A 62-yr-old woman was admitted after femoral-popliteal bypass and developed a reperfusion pain syndrome not relieved with opioids, gabapentin, amitryptiline, and clonidine. In both patients, a sciatic plexus catheter was placed with resolution of pain. Conventional nerve stimulation, which uses a pulse duration of 0.1 msec, did not result in muscle contraction. However, by using a nerve stimulator capable of delivering a 1.0 msec impulse duration, a muscle twitch or paresthesia endpoint ensued allowing for successful catheter placement.Peripheral plexus catheters provide a safe alter-native to systemic analgesics for pain relief in patients with ischemic foot pain. However, conventional nerve stimulation techniques may not elicit a motor response in patients with underlying neuropathy, and the use of nerve stimulators capable of delivering long current impulses is recommended.

Distribution of the Aplysia cardioexcitatory peptide, NdWFamide, in the central and peripheral nervous systems of Aplysia.

NdWFamide is an Aplysia cardioexcitatory tri-peptide containing D-tryptophan. To investigate the roles of this peptide, we examined the immunohistochemical distribution of NdWFamide-positive neurons in Aplysia tissues. All the ganglia of the central nervous system (CNS) contained NdWFamide-positive neurons. In particular, two left upper quadrant cells in the abdominal ganglion, and the anterior cells in the pleural ganglion showed extensive positive signals. NdWFamide-positive processes were observed in peripheral tissues, such as those of the cardio-vascular system, digestive tract, and sex-accessory organs, and in the connectives or neuropils in the CNS. NdWFamide-positive neurons were abundant in peripheral plexuses, such as the stomatogastric ring. To examine the NdWFamide contents of tissues, we fractionated peptidic extracts from the respective tissues by reversed-phase high-pressure liquid chromatography and then assayed the fractions by competitive enzyme-linked immunosorbent assay. A fraction corresponding to the retention time of synthetic NdWFamide contained the most immunoreactivity, indicating that the tissues contained NdWFamide. The prevalence of the NdWFamide content was roughly in the order: abdominal ganglion >heart >gill >blood vessels >digestive tract. In most of the tissues containing NdWFamide-positive nerves, NdWFamide modulated the motile activities of the tissues. Thus, NdWFamide seems to be a versatile neurotransmitter/modulator of Aplysia and probably regulates the physiological activities of this animal.

Percutaneous electrode guidance: A noninvasive technique for prelocation of peripheral nerves to facilitate peripheral plexus or nerve block

Background and Objectives: Typically, peripheral nerve block is done by approximating nerve location, usually by use of anatomical landmarks. Precise nerve location has been done by needle exploration. A new method, percutaneous electrode guidance (PEG) of the block needle, was performed. A transcutaneous stimulating cylindrical electrode was used to indent the skin, locate the underlying nerve, and guide a block needle near it. Methods: PEG was used to prelocate the desired nerve or neural plexus by use of a shielded cylindrical electrode with a 1-mm-diameter conductive area of skin contact at the distal end, the center of which contained a 22-gauge (1/2 mm) hole, which precisely matched a shielded conventional block needle. Transcutaneous stimulation began at less than 10 mA and was decreased to minimal amperage that elicited the desired motor response. Electrode position was fixed, and electrode current was discontinued. A shielded 22-gauge block needle was advanced through the electrode guide to near the underlying nerve. Initial needle current was only 0.5 mA. Local anesthetic was injected to block the targeted nerve or nerves. Standard sensory/motor testing was performed at 20 minutes. Results: Nine upper or lower extremity blocks were performed on 7 patients. All were successful. Minimal stimulating currents were 1.3 to 8.2 mA for transcutaneous electrode stimulation and 0.20 to 0.70 for needle stimulation. Needle depth was 0.4 to 1.1 cm beyond the electrode tip and correlated with minimal electrode stimulating current. Conclusions: A smooth, metal-tipped electrically shielded skin electrode probe can be used to comfortably and accurately indent the skin over a desired nerve or plexus, define its anatomical course, and subsequently guide a block needle near it. Reg Anesth Pain Med 2002;27:261-267.

Catecholamine-containing cells in the central nervous system and periphery of Aplysia californica.

Previous studies have suggested the presence of numerous catecholamine-containing cells in both the central ganglia and peripheral tissues of Aplysia, but they often offered conflicting or incomplete accounts of numbers, locations, and morphologies. The current study combines aldehyde-induced histofluorescence and tyrosine hydroxylase-like immunoreactivity together with confocal microscopy to provide details of these cells. Approximately 35-50 neurones in the cerebral ganglia, 4-8 neurones in the pedal ganglia, 5 neurones in the buccal ganglia, and numerous small fibres in various nerve trunks exhibited both immunoreactivity and aldehyde-induced fluorescence. Approximately 20 cells in the pedal ganglia and 4 cells in the buccal ganglia exhibited only immunoreactivity whereas 15-20 neurons in the cerebral ganglia exhibited only aldehyde-induced fluorescence. No somata in the pleural or abdominal ganglia exhibited aldehyde-induced fluorescence or immunoreactivity. Both aldehyde-induced histofluorescence and immunoreactivity also labelled what appeared to be two classes of catecholamine-containing cells in the gill, siphon, oesophagus, rhinophore, tentacle, and reproductive organs. The more numerous, but smaller cells had subepithelial somata and processes penetrating the overlying body wall, thus suggesting a sensory function. Another class of neurones had larger somata, often located more deeply within the tissue, and occasionally appeared to be multipolar. Processes from these various peripheral cells appeared to comprise the major component of afferent fibres and to form an extensive peripheral plexus, often associated with various muscles. The morphologies of the peripheral cells thus suggest involvement in both local and centrally mediated reflexes and responses, but additional studies must test such hypothesised functions and determine the sensory modalities that the cells mediate.

Prenatal origins of human intrapulmonary arteries formation and smooth muscle maturation

Recent studies on the morphogenesis of the pulmonary arteries have focused on nonhuman species such as the chick and the mouse. Using immunohistochemical techniques, we have studied 16 lungs from human embryos and fetuses from 28 d of gestation to newborn, using serial sections stained with a panel of antibodies specific for endothelium, smooth muscle, and extracellular matrix proteins. Cell replication was also assessed. Serial reconstruction showed a continuity of circulation between the heart and the capillary plexus from at least 38 d of gestation. The intrapulmonary arteries appeared to be derived from a continuous expansion of the primary capillary plexus that is from within the mesenchyme, by vasculogenesis. The arteries formed by continuous coalescence of endothelial tubes alongside the newly formed airway. Findings were consistent with the pulmonary arterial smooth muscle cells being derived from three sites in a temporally distinct sequence: the earliest from the bronchial smooth muscle, later from the mesenchyme surrounding the arteries, and last from the endothelial cells. Despite their different origins, all smooth muscle cells followed the same sequence of expression of smooth muscle‐specific cytoskeletal proteins with increasing age. The order of appearance of these maturing proteins was from the subendothelial cells outward across the vessel wall and from hilum to periphery. The airways would seem to act as a template for pulmonary artery development. This study provides a framework for studying the signaling mechanisms controlling the various aspects of lung development. The past few years have seen advances in our understanding of pulmonary endothelial and smooth muscle cell phenotype and function, and yet our understanding of the origins of the human pulmonary arteries is still based on the reconstructions of embryos described by Congdon in 1922 (1). Later studies showed that intrapulmonary preacinar airway and arterial branching is complete by 16 wk of gestation (2), but the origins of the capillary plexus and its connection with the pulmonary arteries have remained unclear. A recent study has shown that in the mouse, the pulmonary circulation appears to derive from two sources (3). In that study, using casts and electron microscopy, segmental arteries were shown to develop by angiogenesis from the extrapulmonary circulation, and simultaneously, the peripheral capillary plexus formed by vasculogenesis from the pulmonary mesenchyme. The communication between the two was completed at 13 to 14 d of gestation (3). In the present study, we have studied the development of the capillary plexus in human embryonic and fetal lungs on serial sections, having immunostained the endothelial cells for expression of cluster of differentiation number 31 (CD31) and von Willebrand factor. Newly formed endothelial tubes in the systemic and pulmonary circulation become invested by smooth muscle cells, but the origins of these cells are not certain. In vitro studies indicate that smooth muscle cells may be recruited by the endothelium from the surrounding mesenchyme or arise by transdifferentiation from the endothelium (4). In the systemic circulation of the developing quail embryo, mesenchymal cells associating with the endothelium express smooth muscle‐specific a -actin ( a -SM-actin) and these committed cells then express more smooth muscle cell markers as they mature (5). The phenotype of vascular smooth muscle cells varies, with adult bovine and porcine pulmonary arteries containing several different cell phenotypes, differing in their cytoskeletal composition (6, 7). In the present study, we have explored the hypothesis that the different muscle phenotypes have different developmental origins. We have examined the temporal and spatial pattern of pulmonary arterial smooth muscle maturation by studying the expression of smooth muscle‐specific, contractile, and cytoskeletal proteins using immunohistochemical labeling in the human fetal lung. Cell migration during tissue morphogenesis is regulated in part by the composition of the tissue matrix. Fibronectin is a chemoattractant for mesenchymal cells (8), and in vitro migration of smooth muscle cells is dependent on fibronectin (9). Expression of tenascin mediates cell migration and proliferation (10‐12). Versican is expressed at sites of tissue interaction in the developing fetal mouse where it regulates paths of cell migration (13, 14). Therefore, we also examined the temporal and spatial distribution of these three proteins in relation to the development of the pulmonary arteries.

The Effects of Intermittent Pneumatic Compression on Systemic and Local Fibrinolysis

Intermittent pneumatic compression (IPC) is effective in deep venous thrombosis prophylaxis. IPC prevents venous stasis by collapsing the peripheral venous plexus in an extremity leading to increased venous return. It has been suggested that IPC has an additional effect of enhancing fibrinolysis. This study was designed to evaluate the effect of IPC on both systemic and local fibrinolysis in normal volunteers by measuring the activity of tissue plasminogen activator (t-PA) and plasminogen activator inhibitor-type 1 (PAI-1). In addition, tissue factor pathway inhibitor (TFPI) was measured to assess changes in the extrinsic coagulation cascade. IPC was applied in the foot and calf of 10 healthy subjects and blood was drawn from the antecubital fossa to determine systemic fibrinolytic activity. Local fibrinolysis was assessed in 15 healthy subjects by placing an IPC cuff on the forearm and drawing blood 2 cm above the cuff The IPC maximum inflation pressure was 120 mm Hg lasting for 3 seconds at three cycles per minute. Blood samples were taken at rest, on the 10th minute of active IPC, and 5 minutes after cessation of IPC for both systemic and local measurements. The plasma was analyzed for TFPI, t-PA, and PAI-1 antigen by use of enzyme-linked immunosorbent assays. There were no significant changes in systemic or local fibrinolytic activity before, during, or after application of IPC. TFPI systemic activity before, during, and after was 111 ±24, 118 + 18, and 116 ±22, respectively. Local TFPI activity was 91 ±32, 93 +36, and 91 ± 24, respectively. The t-PA systemic activity before, during, and after was 4.1 ± 1.9, 4.7 ± 2.3, and 5 + 2.8, respectively. Local t-PA activity was 4.5 ± 1.3, 4.5 ± 1.4, and 4.2 ± 1.4, respectively. Systemic PAI-1 activity was 11 ± 9.2, 17 ± 19, and 17 ±31, respectively. Local PAI-I activity was 3.7 ± 3.1, 3 ± 1, and 2.8 + 1, respectively, p &gt; 0.38 for all comparisons in both groups. No evidence was found that IPC enhances systemic and local fibrinolysis or TFPI release. Irrespective of the length of IPC application or the inflation pressure, several studies have reported increased fibrinolysis, whereas others have not found any changes. Although, according to the literature, there is a trend toward increased fibrinolytic activity, further controlled studies with adequate sample size should be performed to provide an answer to this controversial topic.

DOES CESAREAN SECTION DECREASE THE INCIDENCE OF BIRTH TRAUMA? † 1422

The objective of this study is to determine if the increase in frequency of cesarean section (C/S) is associated with a decreased incidence of major birth trauma. A retrospective cohort study was performed looking at all neonatal cases of major birth trauma occurring from 1/89 to 12/94. Major birth trauma was defined as peripheral plexus or nerve injuries, fractures, and inadvertent surgical as well as traumatic lacerations. Neonates with minor birth trauma such as scalp clip injuries, cephalohematomas, bruises, and forceps marks were excluded. Charts of newborns and mothers were reviewed. Data was grouped into two mutually exclusive time periods (1/89 to 12/90 vs. 1/91 to 12/94) in which a significant difference in the C/S rate was suspected. The incidence of overall major birth trauma as well as the relative risk and 95% confidence interval (CI) of specific subtypes of birth trauma were calculated and compared between the time periods using the Chi-square test. To evaluate the role of changing delivery patterns on overall birth trauma, a stratified analysis and Mantel-Haenszel test were performed. The results showed that of 17,957 deliveries during the study period, 141 cases of birth trauma occurred. 137 of the 141 records were available for review, and 116 were classified as major trauma and are included in this analysis. The overall incidence of major birth trauma was 6.5 cases/1000 deliveries. During the two year time period(1/89 to 12/90), 18.3% of deliveries were by C/S, and the major birth trauma rate was 8.4 cases/1000 deliveries. During the following 4 year period, the C/S rate was 22.3% with the major birth trauma rate of 5.3 cases/1000 deliveries. A statistically significant difference in the birth trauma(χ2=6.12, p=.013) and C/S (χ2=40.80, p<.001) rate was observed. Controlling for the mode of delivery between the time periods lessened the association between time period and birth trauma incidence(χ2MH=3.28, p=.07) suggesting that this change in C/S rate is responsible for part of the observed difference in birth trauma between the time periods. To further evaluate this finding, we compared the rates of major birth trauma between the time periods stratified by type of delivery. A significant decrease in the risk of major birth trauma in patients delivered by C/S in the later time period was discovered (RR=.46, 95%CI, 0.22-0.97), but there was no difference in those delivered vaginally. This decrease in C/S related birth trauma appeared to be mediated by a decrease in total lacerations between the time periods (χ2=11.76, p<.001) as there was no difference in the rates of other types of major birth trauma(fractures, palsies) in neonates of C/S or vaginally delivered patients. The conclusion of this study is that with a four percent increase in rate of C/S at our institution, a significant decrease in the occurrence of major birth trauma was noted. This finding cannot be explained by a decreased risk of trauma in patients delivering vaginally, but rather by a decreased risk of trauma at C/S in the latter time period.

The vasopressin-like immunoreactive (VPLI) neurons of the locust, Locusta migratoria. I. Anatomy

Antiserum to arginine-vasopressin has been used to characterise the pair of vasopressin-like immunoreactive (VPLI) neurons in the locust. These neurons have cell bodies in the suboesophageal ganglion, each with a bifurcating dorsal lateral axon which gives rise to predominantly dorsal neuropilar branching in every ganglion of the ventral nerve cord. There are extensive beaded fibre plexuses in most peripheral nerves of thoracic and abdominal ganglia, but in the brain, the peripheral plexuses are reduced while neuropilar branching is more extensive, although it generally remains superficial. An array of fibres runs centripetally through the lamina-medulla chiasma in the optic lobes. Lucifer Yellow or cobalt intracellular staining of single VPLI cells in the adult suboesophageal ganglion shows that all immunoreactive processes emanate from these two neurons, but an additional midline arborisation (that was only partially revealed by immunostaining) was also observed. Intracellularly staining VPLI cells in smaller larval instars, which permits dye to reach the thoracic ganglia, confirms that there is no similar region of poorly-immunoreactive midline arborisation in these ganglia. It has been previously suggested that the immunoreactive superficial fibres and peripheral plexuses in ventral cord ganglia serve a neurohaemal function, releasing the locust vasopressin-like diuretic hormone, F2. We suggest that the other major region of VPLI arborisation, the poorly immunoreactive midline fibres in the suboesophageal ganglion, could be a region where VPLI cells receive synaptic input. The function of the centripetal array of fibres within the optic lobe is still unclear.

Occurrence of 5-hydroxytryptamine (serotonin) in the nervous system of a monogenean, Diclidophora merlangi

Both whole-mount preparations and cryostat sections of the monogenean, Diclidophora merlangi, were screened for the presence of 5-hydroxytryptamine-like immunoreactivity, using an indirect immunofluorescence technique. Immunostaining was evident in cell bodies and fibres comprising the longitudinal cords of the central nervous system and in the peripheral plexuses that innervate the musculature of the adhesive organs, feeding apparatus and accessory ducts of the reproductive system. The subsurface nerve-net was reactive, and a distinctive “collar” of staining marked a plexus of nerves and somata that supply the subtegumental muscles of the extensile forebody.