The effect of pain stimulation on the mitotic activity of the epithelium of the small intestine in hypophysectomized rats

Summary A study was made of the effect produced by pain stimulus on the mitotic activity in the Liberkühn crypt epithelium of the small intestine in control and hypophysectomized rats. 40 minutes after division of the sciatic nerve there occurred stimulation of the cellular mitosis in the Lieberkühn crypt epithelium in control animals and inhibition of mototic activity in the intestinal epithelium of hypophysectomized rats.(Presented by Active Member AMN SSSR N. A. Kraevskii) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 55, No. 3, pp. 109–113, March, 1963.     

Pain syndrome in rats after injury to the sciatic nerve]

Chronic experiments were conducted on rats to study the peculiarities of changes of pain sense and the components of the microcirculatory system after division of the sciatic nerve. It was established that division of the sciatic nerve leads in 1-2 weeks to the development of hyperalgesia, the appearance of autotomies, disorders of the microcirculatory system, which are evidence of the development of the pain syndrome.     

人脐带间充质干细胞不同部位移植对压力性尿失禁治疗作用的研究

目的研究尿道周围及坐骨神经近端移植人脐带间充质干细胞（hUCMSCs）是否可以提高压力性尿失禁大鼠的尿道闭合压。改善其储尿能力。方法模拟绝经和产伤构建压力性尿失禁大鼠模型,并用漏尿点压力（LPP）、最大膀胱容积（MCC）及“模拟喷嚏”实验进行检测。将hUCMSCs分别注射移植到压力性尿失禁大鼠的尿道周围及坐骨神经近端。1个月后再次检测漏尿点压力及最大膀胱容积。结果移植后1个月,尿道周围治疗组与尿道周围模型组MCC差值差异无统计学意义（P〉0．05）;而尿道周围治疗组LPP增高,尿道周围模型组LPP降低,两组差值差异有统计学意义（P〈0．01）。移植后1个月．坐骨神经治疗组MCC和LPP与坐骨神经模型组相比,其差值差异均无统计学意义（P值均〉0．05）。结论人脐带间充质干细胞注射移植到尿道周围可以提高压力性尿失禁大鼠的尿道闭合压,但不能改善其储尿能力;而移植到坐骨神经近端短期内不能改善压力性尿失禁大鼠的储尿能力。     

Changes in the capillary bed of skeletal muscle at various times after nerve section

Quantitative changes in the capillary bed of the gastrocnemius muscle of rats were studied after division of the sciatic nerve. The total (functioning) capillary bed was identified by intravenous injection of black ink. Functioning capillaries were detected by the discovery of erythrocytes in their lumen, using a histochemical method for demonstrating peroxidases with the aid of benzidine and hydrogen peroxide. The number of capillaries and fibers was counted in transverse sections through the muscle and the coefficient of capillarization was calculated. The investigation showed that the functioning capillary bed falls by 36% during the first 10 days, and the total capillary bed falls by 28.6% in 20 days. In the period of reinnervation (30th day) an increase was observed both in the total number of capillaries and in the number of functioning capillaries.Laboratory of General Pathophysiology and Experimental Therapy, Institute of General Pathology and Pathological Physiology, Academy of Medical Sciences of the USSR, Moscow. Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 80, No. 9, pp. 12–16, September, 1975.     

Anatomical comparison of sciatic nerves between adults and newborns: clinical implications for ultrasound guided block

The sciatic nerve (SN) is easily blocked under ultrasound guidance by identifying either the SN common trunk or its two components: the tibial nerve (TN) and the common peroneal nerve (CPN). The authors investigate whether there are anatomical differences between newborns and adults. The SN, TN and CPN of both lower extremities in 24 (11 neonatal and 13 adults) formolized cadavers were dissected. Distances were measured from the origin of the SN (passing under the piriformis muscle) to its division into TN and CPN, and from there to the popliteal crease. The sciatic/thigh coefficient (proportion relating SN length to thigh length) and the variation coefficient for the SN were calculated. The distance from the popliteal crease to the SN division was significantly shorter in neonates than in adults (1.04 ± 0.9 cm vs. 5.6 ± 5.1 cm, P = 0.0003). In addition, the neonatal SN divided at a proportionally more distal position in the thigh than it did in adults (86 ± 13 vs. 74 ± 15%, P = 0.0059). However, the coefficient of variation between the SN‐division distances was not statistically different in infants and adults (12.8 vs. 18.2%, P = 0.4345). The variations in the point of SN division seen in the adult SN are already seen in the neonatal period, but in newborns the SN divided in a more distal position in relation to the thigh than in adults, so this finding of anatomical variability in neonates suggests that ultrasound guidance can be useful when performing a SN block in these small patients.     

Pharmacological enhancement of peripheral nerve regeneration in the rat by systemic acetyl-L-carnitine treatment

Peripheral nerve trauma remains a major cause of morbidity, largely due to the death of approximately 40% of innervating sensory neurons, and to slow regeneration after repair. Acetyl-L-carnitine (ALCAR) is a physiological peptide that virtually eliminates sensory neuronal death, and may improve regeneration after primary nerve repair. This study determines the effect of ALCAR upon regeneration after secondary nerve repair, thereby isolating its effect upon neuronal regenerative capacity. Two months after unilateral sciatic nerve division 1 cm nerve graft repairs were performed (n=5), and treatment with 50 mg/kg/day ALCAR was commenced for 6 weeks until harvest. Regeneration area and distance were determined by quantitative immunohistochemistry. ALCAR treatment significant increased immunostaining for both nerve fibres (total area 264% increase, P<0.001; percentage area 229% increase, P<0.001), and Schwann cells (total area 111% increase, P<0.05; percentage area 86% increase, P<0.05), when compared to no treatment. Regeneration into the distal stump was greatly enhanced (total area 2,242% increase, P=0.008; percentage area 3,034% increase, P=0.008). ALCAR significantly enhances the regenerative capacity of neurons that survive peripheral nerve trauma, in addition to its known neuroprotective effects.     

Non-myelin-forming Schwann cells proliferate rapidly during Wallerian degeneration in the rat sciatic nerve

Summary Transection of a mixed peripheral nerve results in the degeneration of axons and breakdown of myelin in the distal stump. These events are accompanied by a sharp but transient Schwann cell proliferation. The present study seeks to determine whether both myelin-forming and non-myelin-forming Schwann cells enter a proliferative phase under these conditions, or whether the dividing cells are chiefly recruited from one or other of the Schwann cell populations. The macrophage recruitment into the transected distal stumps has also been timed and quantitated, since it has been suggested that macrophages are an important source of Schwann cell mitogens in degenerating peripheral nerves.Incorporation of [³H]-thymidine and autoradiography was used as a measure of cell proliferation, and cell type markers and immunohistochemistry were used to identify myelin-forming and non-myelin-forming Schwann cells. The cells were removed from the distal stump of the rat sciatic nerve and sympathetic trunk at various times after transection and proliferation measured during the first 24 h in culture. It was found that in the sciatic nerve, which contains a mixture of myelinated and unmyelinated fibres, both myelin-forming cells, identified by presence of the myelin protein P_o, and non-myelin-forming cells (P_o ^– cells) showed a substantial elevation in [³H]-thymidine labelling index at day 2 postoperatively, which was similar in magnitude for the two categories of cell. The proliferation rate of both P_o ⁺ and P_o ^– cells remained elevated for up to 8 days after transection. In the largely unmyelinated sympathetic trunk, the peak rate of P_o ^– Schwann cell division reached less than half the peak rate for P_o ^– cells in the sciatic nerve, and cell division fell to a level barely above the control value by postoperative day 4. In the sciatic nerve the number of macrophages, which were identified by monoclonal antibody ED1, rose sharply during the first postoperative day and peaked at day 2.These results provide strong evidence that non-myelin-forming and myelin-forming Schwann cells contribute approximately equally to the initial burst of Schwann cell proliferation seen in the distal stump of the transected rat sciatic nerve. They also indicate that the proliferative response of non-myelin-forming cells is substantially greater in nerves containing many myelinated fibres than in essentially unmyelinated nerves. The timing of macrophage recruitment in the sciatic nerve is consistent with the hypothesis that macrophages are an important source of Schwann cell mitogens during nerve degeneration.     

Histopathological investigation of neuroprotective effects of Nigella sativa on motor neurons anterior horn spinal cord after sciatic nerve crush in rats

The aim of this study was designed to evaluate the possible protective effects of Nigella sativa (NS) on the neuronal injury in the sciatic nerve of rats. The rats were randomly allotted into one of the three experimental groups: A (control), B (only trauma) and C (trauma and treated with NS); each group contain 10 animals. Sciatic nerve injury was performed by placing an aneurysm clip on the left leg. Rats were neurologically tested over 24 h after trauma. The rats in NS-treated group was given NS (in a dose of 400 mg/kg body weight) once a day orally for 30 days starting just after trauma. Control and untreated (only trauma) rats were injected with the same volume of isotonic NaCl as the treated animals that received NS. Tissue samples were obtained for histopathological investigation. To date, no histopathological changes of neurodegeneration in the sciatic nerve after trauma in rats by NS treatment have been reported. Results showed in the group B (only trauma), the neurons of sciatic nerve tissue became extensively dark and degenerated with picnotic nuclei. Treatment of NS markedly reduced degenerating neurons after trauma and the distorted nerve cells were mainly absent in the NS-treated rats. The morphology of neurons in groups treated with NS was well protected, but not as neurons of the control group. The number of neurons in sciatic nerve tissue of group B (only trauma) was significantly less than both control and treated with NS groups. The morphology of neurons revealed that the number of neurons were significantly less in group B compared to control (P < 0.001) and group C (P < 0.01) rats’ motor neurons anterior horn spinal cord tissue. We conclude that NS therapy causes morphologic improvement on neurodegeneration in sciatic nerve after trauma in rats.     

Effects of dichloroacetate on exercise performance in healthy volunteers

Dichloroacetate (DCA), a stimulator of the pyruvate dehydrogenase complex, decreases lactate levels and peripheral resistance and increases cardiac output. This study was performed to examine the effects of DCA on exercise performance in humans. Eight healthy male volunteers (age 20–28 years) were tested by bicycle spiro-ergometry using a microprocessor-controlled gas analysis system after infusion of DCA (50 mg/kg body weight) or saline. Prior infusion of DCA significantly reduced the increase of lactate levels during exercise when compared with infusion of saline (1.40±0.21 vs 2.10±0.09 mmol·l^–1 at 50% of the expected maximal working capacity, P<0.05; 8.53±0.45 vs 9.92±0.59 mmol·l^–1 at maximal working capacity, P<0.05). Oxygen uptake increased significantly after DCA when compared with saline from 7.5±0.4 vs 7.4±0.5 to 27.2±1.5 vs 23.7±1.7 (P<0.05) at anaerobic threshold and to 35.6±1.7 vs 30.5±1.0 ml · kg^–1 min^–1 (P<0.05) at maximal exercise capacity. Following DCA infusion the workload at which the anaerobic threshold was reached was significantly higher (160±7 vs 120±5 W, P<0.05) and the maximal working capacity was significantly increased (230±9 vs 209±8 W, P<0.05). In summary, DCA reduced the increase of lactate levels during exercise and increased oxygen uptake at the anaerobic threshold and at maximal working capacity, which was significantly increased. These results warrant further studies on a potential therapeutic application of DCA in patients with reduced exercise capacity.     

Survival and regeneration of cutaneous and muscular afferent neurons after peripheral nerve injury in adult rats

Peripheral nerve injury induces the retrograde degeneration of dorsal root ganglion (DRG) cells, which affects predominantly the small-diameter cutaneous afferent neurons. This study compares the time-course of retrograde cell death in cutaneous and muscular DRG cells after peripheral nerve transection as well as neuronal survival and axonal regeneration after primary repair or nerve grafting. For comparison, spinal motoneurons were also included in the study. Sural and medial gastrocnemius DRG neurons were retrogradely labeled with the fluorescent tracers Fast Blue (FB) or Fluoro-Gold (FG) from the homonymous transected nerves. Survival of labeled sural and gastrocnemius DRG cells was assessed at 3 days and 1–24 weeks after axotomy. To evaluate axonal regeneration, the sciatic nerve was transected proximally at 1 week after FB-labeling of the sural and medial gastrocnemius nerves and immediately reconstructed using primary repair or autologous nerve grafting. Twelve weeks later, the fluorescent tracer Fluoro-Ruby (FR) was applied 10 mm distal to the sciatic lesion in order to double-label sural and gastrocnemius neurons that had regenerated across the repair site. Counts of labeled gastrocnemius DRG neurons did not reveal any significant retrograde cell death after nerve transection. In contrast, sural axotomy induced a delayed loss of sural DRG cells, which amounted to 22% at 4 weeks and 43–48% at 8–24 weeks postoperatively. Proximal transection of the sciatic nerve at 1 week after injury to the sural or gastrocnemius nerves neither further increased retrograde DRG degeneration, nor did it affect survival of sural or gastrocnemius motoneurons. Primary repair or peripheral nerve grafting supported regeneration of 53–60% of the spinal motoneurons and 47–49% of the muscular DRG neurons at 13 weeks postoperatively. In the cutaneous DRG neurons, primary repair or peripheral nerve grafting increased survival by 19–30% and promoted regeneration of 46–66% of the cells. The present results suggest that cutaneous DRG neurons are more sensitive to peripheral nerve injury than muscular DRG cells, but that their regenerative capacity does not differ from that of the latter cells. However, the retrograde loss of cutaneous DRG cells taking place despite immediate nerve repair would still limit the recovery of cutaneous sensory functions.     

Double superior gemellus together with double piriformis and high division of the sciatic nerve

Summary We report a case with double superior gemellus and double piriformis mm. associated with the sciatic n. dividing high and passing between the two piriformis mm. in the same lower extremity. This abnormality has not previously been described in the literature. As many musculoskeletal structures may be involved in sciatica, the supernumerary superior gemelli and piriformis mm. may exert pressure on the sciatic n. and this should be taken into account by clinicians.

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Association de muscles jumeau supérieur et piriforme doubles à une division haute du nerf sciatique

Résumé Nous rapportons le cas de l'association de muscles jumeau supérieur et piriforme doubles à une division haute du n. sciatique. Ce nerf avait la particularité de passer entre les deux mm. piriformes. Cette anomalie n'a pas été signalée dans la littérature. De la même manière qu'un certain nombre de structures musculo-squelettiques sont susceptibles de provoquer une névralgie sciatique, la présence de mm. jumeau supérieur et piriforme surnuméraires est susceptible de comprimer le n. sciatique. Aussi cette anomalie doit-elle être connue des cliniciens.

     

Does circadian rhythm disruption induced by light-at-night has beneficial effect of melatonin on sciatic nerve injury?

Melatonin stimulates peripheral nerve regeneration. However, the precise effect of Melatonin on nerve repair in dark period have not been clarified. The aim of the present study was to investigate the effect of melatonin on sciatic nerve injury after melatonin was given to rats in the morning or evening by means of combined analysis. This is the first study to investigate the influence of melatonin on sciatic nerve in cut injury two different times of the day. 60 adult female Wistar rats were divided into 4 groups: control (Group 1), sham-operated (Group 2), sciatic nerve cut + melatonin treatment in light (Group 3), sciatic nerve cut + melatonin treatment in dark (Group 4). Melatonin was administered intraperitoneally at dose of 50 mg/kg/day for six weeks. Recovery of function was analyzed by structural (biochemical properties of the antioxidant levels and ultrastructural analysis) and functional analyses (Sciatic function index, pinch test). The data demonstrated beneficial effect of melatonin in light period. However significant beneficial effect of melatonin was detected on the recovery of the cut sciatic nerve in dark period. Melatonin treatment was unable to influence on the recovery of the cut sciatic nerve in dark period. This means that the effect of melatonin the recovery of the cut injured sciatic nerve depends on the time of treatment may be attributed to its circadian rhythm.     

超声引导注射富血小板血浆修复坐骨神经挤压伤

文题释义：富血小板血浆：是通过离心自体全血而得到的含高浓度血小板的血浆。已证实富血小板血浆中含有多种生长因子,如血小板源性生长因子、转化生长因子β、类胰岛素生长因子1、血管内皮生长因子、神经生长因子、脑源神经营养因子、肝细胞生长因子等。这些生长因子对组织的修复和再生起着重要作用。富血小板血浆由自体血液取样制备,因取材方便、制备较简单,且具有较好的促进组织再生等优点,已被广泛用于骨科领域,如：肌肉、肌腱、韧带、软骨损伤,创面修复,骨折、骨性关节炎、脊柱融合等,并逐年被应用于神经再生的研究。 背景：富血小板血浆富含影响肌腱、韧带、肌肉和骨愈合的生长因子,在此基础上,研究人员逐渐认识到富血小板血浆激活后释放的分子可调节周围神经早期炎症、激活许旺细胞、促进巨噬细胞极化及阻止胶原纤维的增生,成为神经功能恢复的关键驱动力。 目的：探讨超声引导富血小板血浆注射修复坐骨神经挤压伤的价值。 方法：将28只新西兰大白兔(北京隆安动物繁殖中心提供)随机分为4组,每组7只：正常组暴露右侧坐骨神经后直接缝合;对照组建立右侧坐骨神经挤压损伤模型;单频次注射组建立右侧坐骨神经挤压损伤模型,术后24 h于超声引导下在损伤神经周围注射自体富血小板血浆;多频次注射组建立右侧坐骨神经挤压损伤模型,术后24 h于超声引导下在损伤神经周围注射自体富血小板血浆,此后第3,5周各注射1次。术后12周,进行再生神经的组织学、形态学评价及失神经支配肌肉的湿质量恢复与组织学检测。实验经解放军总医院实验动物管理委员会批准(2015-x10-02)。 结果与结论：①与对照组比较,单频次与多频次注射组再生轴突NF-200、S100染色累积吸光度值明显升高(P均< 0.05);多频次注射组二者累积吸光度值高于单频次注射组(P均< 0.05),但仍低于正常组(P均< 0.05);②与对照组比较,单频次与多频次注射组有髓神经纤维密度、有髓神经纤维直径及髓鞘厚度明显增加(P均< 0.05);多频次注射组3指标多于单频次注射组(P均< 0.05),但仍低于正常组(P均< 0.05);③与对照组比较,单频次与多频次注射组肌肉湿质量、肌纤维横截面积增加(P均< 0.05);多频次注射组两指标多于单频次注射组(P均< 0.05),但仍少于正常组(P均< 0.05);④结果表明,超声引导自体富血小板血浆多频次注射治疗坐骨神经挤压伤具有良好的效果。 ORCID: 0000-0002-1974-3221(朱亚琼) 中国组织工程研究杂志出版内容重点：组织构建;骨细胞;软骨细胞;细胞培养;成纤维细胞;血管内皮细胞;骨质疏松;组织工程     

Artificial gravity with ergometric exercise as a countermeasure against cardiovascular deconditioning during 4 days of head-down bed rest in humans

We have shown previously that combined short-arm centrifuge and aerobic exercise training preserved several physiologically important cardiovascular functions in humans. We hypothesized that artificial gravity (AG) and exercise is effective to prevent changes of physical problems during head-down bed rest (HDBR). To test this hypothesis, 12 healthy male subjects had undergone 4 days of 6° HDBR. Six of them were exposed to AG of an alternating 2-min intervals of +1.0 and +2.0 Gz at foot level for 30 min twice per day with ergometric exercise of 40 W as a countermeasure during bed rest (CM group), while the remaining six served as untreated controls (no-CM group). Before and after 4 days of bed rest, leg venous hemodynamics was assessed by venous occlusion plethysmography and autonomic cardiovascular control estimated by power spectral analysis of blood pressure and heart rate. Further, orthostatic tolerance was evaluated by a 75° head-up tilt test and physical working capacity was surveyed by near maximal physical working capacity test before and after bed rest. The data showed that combined centrifuge and exercise applied twice daily for a total of 60 min during 4 days of HDBR prevented (a) a decrease in working capacity, (b) autonomic dysfunction (a decrease in the activity of parasympathetic cardiac innervation) and (c) an increase in leg venous flow resistance. The combination of a 30 min alternating of +1.0 and +2.0 Gz for twice per day of AG with 40 W ergometric exercise may offer a promising countermeasure to short duration simulated microgravity.     

Decreased accumulation of endogenous brain-derived neurotrophic factor against constricting sciatic nerve ligatures in streptozotocin-diabetic and galactose-fed rats

Anterograde and retrograde trafficking of brain-derived neurotrophic factor (BDNF) was examined in streptozotocin-diabetic and galactose-fed rats by measuring accumulation of endogenous neurotrophin proximal and distal to two constricting sciatic nerve ligatures and by direct injection of radiolabeled neurotrophin into the sciatic nerve. Compared to controls, accumulation of endogenous BDNF proximal and distal to the ligatures as well as basal levels in non-ligated nerve segments were decreased in streptozotocin-diabetic and galactose-fed rats. Neither streptozotocin diabetes nor galactose intoxication affected the amount of 125I-labeled BDNF retrogradely transported to the DRG after injection into the sciatic nerve. These results suggest that reduced anterograde and retrograde accumulations of BDNF in experimental diabetes are not a result of impaired capacity for receptor-mediated transport.     

Botulinum neurotoxin type A counteracts neuropathic pain and facilitates functional recovery after peripheral nerve injury in animal models

A growing interest was recently focused on the use of Botulinum neurotoxin serotype A (BoNT/A) for fighting pain. The aim of this study was to investigate the effects of BoNT/A on neuropathic pain. It was observed that BoNT/A is able to counteract neuropathic pain induced by chronic constriction injury (CCI) to the sciatic nerve both in mice and in rats. This effect is already present after a single intraplantar (i.pl.) or intrathecal (i.t.) neurotoxin administration that significantly reduces the sciatic nerve ligation-induced mechanical allodynia in mice and rats and thermal hyperalgesia in rats. This effect was evident starting 24 h after the administration of BoNT/A and it was long-lasting, being present 81 or 25 days after i.pl. injection of the higher dose in mice (15 pg/paw) and rats (75 pg/paw), respectively, and 35 days after i.t. injection in rats (75 pg/rat). Moreover, BoNT/A-injected mice showed a quicker recovery of the walking pattern and weight bearing compared to control groups. The behavioral improvement was accompanied by structural modifications, as revealed by the expression of cell division cycle 2 (Cdc2) and growth associated protein 43 (GAP-43) regeneration associated proteins, investigated by immunofluorescence and Western blotting in the sciatic nerve, and by the immunofluorescence expression of S100β and glial fibrillary acidic protein (GFAP) Schwann cells proteins. In conclusion, the present research demonstrate long-lasting anti-allodynic and anti-hyperalgesic effects of BoNT/A in animal models of neuropathic pain together with an acceleration of regenerative processes in the injured nerve, as evidenced by both behavioral and immunohistochemistry/blotting analysis. These results may have important implications in the therapy of neuropathic pain.     

Exploratory factor analysis of neuropsychological tests and their relationship to the Brown–Peterson task

The interference condition of the Brown–Peterson task and the auditory consonant trigrams test was designed to evaluate working memory in that it required a division of attentional processes to complete two cognitive tasks. However, the specific cognitive functions contributing to the performance of this interference task have yet to be determined. The objective of this study was to determine what other tasks are comparable to the Brown–Peterson task and conduct an exploratory factor analysis that included the measures from the Brown–Peterson task and other neuropsychological measures. A neuropsychological battery was administered to younger participants (n = 107, mean age = 20.83) and older participants (n = 93, mean age = 70.14). Factor analysis yielded a two-factor solution. Performance after the intervening serial subtraction task loaded on an auditory/visual working memory and complex attention factor and had common loadings with working memory subtests of the WAIS-III and the spatial span subtest of the WMS-III. Results suggest that the performance after the intervening serial subtraction task evaluates dual information processing, complex attention, and working memory.     

The effect of high-intensity exercise on the respiratory capacity of sceletal muscle

The effect of high-intensity exercise on the respiratory capacity of skeletal muscle was studied in horses which ran five 600-m bouts on a track with 2 min of rest between exercise bouts, or once to fatigue on a treadmill at an intensity that elicited the maximal oxygen uptake. Venous blood and biopsy samples of the middle gluteal muscle were collected at rest, after each exercise bout, and 30 and 60 min post-exercise. Blood samples were analyzed for lactate concentration and pH and muscle samples for metabolites, pH, and respiratory capacity. Venous blood and muscle pH declined to 6.91±0.02 and 6.57±0.02, respectively, after the fifth track run and to 6.98±0.02 and 6.71±0.07, respectively, after treadmill running. Muscle metabolite changes were consistent with the metabolic response to high-intensity exercise. Muscle respiratory capacity declined >20% (P<0.05) after a single exercise bout and was 45% of the control value after the fifth track run. Tissue respiration was depressed 60 min post-exercise but was normal 24 h later. These observations suggest that high-intensity exercise impairs the respiratory capacity of the working muscle. Although this occurred in parallel with reductions in pH, other factors could be responsible for this response.     

Prox1 induces new lymphatic vessel formation and promotes nerve reconstruction in a mouse model of sciatic nerve crush injury

The peripheral nervous system lacks lymphatic vessels and is protected by the blood–nerve barrier, which prevents lymphocytes and antibodies from entering the neural parenchyma. Peripheral nerve injury results in degeneration of the distal nerve and myelin degeneration causes macrophage aggregation, T lymphocyte infiltration, major histocompatibility complex class II antigen expression, and immunoglobulin G deposition in the nerve membrane, which together result in nerve edema and therefore affect nerve regeneration. In the present paper, we show myelin expression was absent from the sciatic nerve at 7 days after injury, and the expression levels of lymphatic vessel endothelial hyaluronan receptor 1 (LYVE-1) and Prospero Homeobox 1 (Prox1) were significantly increased in the sciatic nerve at 7 days after injury. The lymphatic vessels were distributed around the myelin sheath and co-localized with lymphatic endothelial cells. Prox1 induces the formation of new lymphatic vessels, which play important roles in the elimination of tissue edema as well as in morphological and functional restoration of the damaged nerve. This study provides evidence of the involvement of new lymphatic vessels in nerve repair after sciatic nerve injury.     

Reactions of neurons of the mediodorsal nucleus of the thalamus to the stimulation of peripheral nerves

The reactions of neurons of the associative mediodorsal nucleus of the thalamus to a solitary stimulation of the radial, sciatic, and splanchnic nerves were studied in conditions of an acute experiment in anesthetized and immobilized cats. There were 91.85, 90.56, and 81.35% reactive neurons, respectively. They were mainly concentrated in the parvocellular division of the nucleus. A high degree of convergence (82.6%) of somatic and visceral signals was found and their interaction was of the reciprocal blocking type.Translated from Fiziologicheskii Zhurnal SSSR imeni I. M. Sechenova, Vol. 76, No. 11, pp. 1528–1537, November, 1990.