[Study of expression of slit2 mRNA in rats of different age after sciatic nerve injury]

OBJECTIVE

To determine the age-related expression features of slit2 mRNA at various intervals at the proximal and distal parts of sciatic nerve during re-innervation after severance injury, and to investigate the molecular biological reason why co-contraction occurs more commonly in the young rats than in the adults after peripheral nerve injury.

METHODS

The right sciatic nerve was transected sharply at the midthigh in the young and adult rats, 28 in each group. The proximal and distal stumps were inserted into a medical silicone tube with a gap of 3 mm. Before the injury, and 1, 3 and 7 days (6 rats at each interval) after sciatic nerve severance injury, both stumps of the sciatic nerve were harvested. Reverse transcription polymerase chain reaction (RT-PCR) was use to examine the expression of slit2 mRNA in the young and adult group rats. In situ hybridization was done to detect the cell location of slit2 mRNA expression in young and adult rats, 4 rats in each group, 2 rats used before the injury and 2 rats used on the postoperative third day.

RESULTS

RT-PCR results suggested that slit2 mRNA at both stumps was significantly lower in the young group of rats than in the adult except that at the proximal part on the postoperative 7th day. There was statistically significant difference (P < 0.01). In situ hybridization studies indicated that the slit2 mRNA was specifically expressed in the cytoplasm of Schwann cells both in the young and adult rats before injury and 3 days after injury.

CONCLUSION

The expression of slit2 mRNA by Schwann cells in the young rats is lower than that in the adult rats after peripheral nerve injury. These findings suggests the lower expression of chemotactic factor (slit2) by Schwann cells in the young group is likely to be the molecular biological reason for the higher incidence of co-contraction between agonists and antagonists in the younger rats.

Functional reconstruction of the irreparable upper trunk defect of the brachial plexus--a case report

We report a successful application of Oberlin's procedure combined with transfer of trapezius and latissimus dorsi with the teres major for reconstruction of elbow flexion as well as abduction and external rotation of the shoulder to a ten-year-old patient, who had a long defect of the left brachial plexus upper trunk caused by resection of the plexiform neuroma.

Selective neurotization of the median nerve in the arm to treat brachial plexus palsy. An anatomic study and case report

BACKGROUND

The current method for treatment of median nerve palsy after a brachial plexus injury is unpredictable. On the basis of an anatomic study of the median nerve in the arm, we present a new method of selective neurotization of the median nerve.

METHODS

Internal topographic features of the fascicular groups of the median nerve were observed in seventeen cadavera. On the basis of the anatomical results, selective neurotization of the posterior fascicular group of the median nerve in the arm was performed in one patient with a complete brachial plexus palsy.

RESULTS

In the distal half of the arm, the branches of the median nerve consistently collect into three fascicular groups, which are located at the anterior, middle, and posterior parts of the median nerve trunk. The anterior fascicular group is composed of the branches to the pronator teres and the flexor carpi radialis, the posterior fascicular group is composed mainly of the anterior interosseous nerve and the branches to the palmaris longus, and the middle fascicular group is made up mostly of the branches to the hand and the flexor digitorum superficialis. A transfer of the full length of the phrenic nerve was used to selectively reinnervate the posterior fascicular group of the median nerve in a patient with a complete brachial plexus palsy. The muscles supplied by the posterior fascicular group regained Grade-4 power, according to the system of the Medical Research Council, sixteen months after surgery.

CONCLUSIONS AND CLINICAL RELEVANCE

The typical arrangement of the fascicular groups of the median nerve in the arm favors the technique of selective neurotization, which has been used effectively in one patient to date.

Electrophysiologic study of influence on C7 innervated muscles after transection of different C7 fascicles

An experimental study was conducted to observe the electrophysiologic changes in C7 innervated muscles following transection of different fascicles of C7 nerve root in the brachial plexus with already transected C5 and C6. Twenty-four Sprague-Dawley rats were randomized into groups A, B, and C. C5 and C6 transection, C5, C6, and partial C7 (anteriolateral fascicles of the anterior division) transection, and C5, C6, and C7 transection were done in group A, B, and C, respectively. One month postoperatively, compound muscle action potentials of the latissimus dorsi, triceps, and extensor digitorum communis were recorded. Decreased amplitude and a prolonged latent period were seen in all three muscles of group C. No obvious changes, however, were found in groups A and B. This suggests that when the upper trunk of the brachial plexus is injured, partial transection of C7 does not obviously impair C7 innervated muscle function. Selective ipsilateral C7 transfer is safe for the treatment of upper-trunk avulsion.

Distally based radial forearm flap with preservation of the radial artery: anatomic, experimental, and clinical studies

In this article we report on the anatomical, experimental, and clinical investigations of the distally adipofascial pedicled radial forearm flap based on the small perforators around the radial styloid process. There are about 10 small perforators (0.3-0.5 mm in diameter) from the distal radial artery around the radial styloid process. The longitudinal chain-linked vascular plexuses (suprafascial, paraneural, and perivenous) formed by the forearm ascending and descending branches of septofasciocutaneous perforators meet and cross over with the transverse carpal vascular plexuses around the radial styloid region. Based on these directional-oriented plexuses, distally based adipofascial pedicled radial forearm fasciocutaneous and adipofascial flaps were designed and successfully applied in 34 clinical cases. The pivot point was located at 1-2 cm above the radial styloid. The skin island plus adipofascial pedicle measured between 9-18 cm in length, with the adipofascial pedicle 3-4 cm in width. The length-to-width ratio is 3-5:1. The venous drainage of this distally based flap was investigated anatomically and experimentally. The cephalic vein has no positive role for venous drainage in distally based flaps. The difference between distally based flaps and reverse-flow flaps, clinical selection of fasciocutaneous and adipofascial flaps, advantages and disadvantages, and technical tips for operative success are discussed.

Modified distally based peroneal artery perforator flap for reconstruction of foot and ankle

The distally based sural fasciocutaneous flap has been used widely for reconstruction of foot and ankle soft-tissue defects. Here we report on a series of cases of foot and ankle reconstruction with a modified distally based sural flap. The vascular pedicle of the flap includes an axial perforator branch of the peroneal artery and two concomitant veins. This modified distally based perforator flap, measuring around 17 x 6 cm to 30 x 10 cm in size, was transferred for coverage of foot and ankle soft-tissue defects in 7 cases. All flaps survived completely. Neither arterial ischemia nor venous congestion was noted. As compared to other distally based sural flaps with neuro-veno-adipo-fascial pedicles, this modified sural flap with a thin perforator pedicle is easily rotated. The flap can obtain abundant blood supply through both axial perforator and longitudinal chain-linked vascular plexuses, and does not have the venous reflow problem. In conclusion, the invention of this perforator fasciocutaneous flap provides a valuable tool for repair of foot and ankle soft-tissue defects.

Comparative experimental study on treatment outcome of nerve transfer, using selective C7 nerve root vs. phrenic nerve

The treatment outcome of nerve transfer using the C7 nerve root or phrenic nerve was compared in a rat experiment. One hundred and twenty SD rats were divided into two groups, one undergoing phrenic nerve transfer to the musculocutaneous nerve, and the other partial ipsilateral C7 (anteriolateral fascicles of the anterior division) to the musculocutaneous nerve. Neurotization outcomes of the two groups were evaluated by comparing the electrophysiologic, histologic, and myophysiologic changes of the biceps muscle. No significant differences were found between parameters from the phrenic nerve transfer group and those from the ipsilateral C7 nerve transfer group. This indicates that the treatment outcome of selective ipsilateral C7 transfer is comparable to that of phrenic nerve transfer. It is the surgery of choice in treating brachial plexus upper-trunk avulsion accompanied by phrenic nerve injury.

Comparison of different managements of large superficial veins in distally based fasciocutaneous flaps with a veno-neuro-adipofascial pedicle: An experimental study using a rabbit model

The role of large superficial veins in the survival of a distally based fasciocutaneous flap with a veno-neuro-adipofascial pedicle was studied in a rabbit model. A sural veno-neuro-fasciocutaneous flap model (6 x 2 cm) with a distally based lesser saphenous veno-neuro-adipofascial pedicle (1.5 cm) was established. Fifteen rabbits were randomly divided into three groups with 10 flaps in each group. In group I, the distal lesser saphenous vein was left open (venous inflow remained) after the flap was raised. In group II, the lesser saphenous vein was ligated in the pedicle (no venous inflow). In group III, the venous pedicle was left open in the pedicle, and the proximal end was microsurgically anastomosed to the recipient vein (outflow established). Intravenous pressure, flap survival, and histology were examined. The results showed that the values of intravenous pressure in group I were significantly higher than in group II (P < 0.001). The mean flap survival rate of group III (94.5%) was significantly higher (P < 0.001) than of groups I (22.7%) and II (55.5%). Histology showed that the lesser saphenous vein in group I was extremely dilated and filled with thrombosis. This experiment demonstrated that establishing a superficial venous outflow channel by anastomosis at the proximal end, or interrupting the inflow channel by ligation at the distal pedicle, may significantly improve the survival rate of distally based veno-neuro-fasciocutaneous flaps.

Comparison of venous drainage in reverse-flow island flaps: an experimental study of the rabbit saphenous fasciocutaneous flap

The mechanism of venous drainage in reverse-flow island flaps was investigated using the saphenous fasciocutaneous flap in New Zealand White rabbits. Ten animals were allocated into two groups of 10 flaps. In group I (left limb), the distal vascular pedicle (one saphenous artery and two venae comitantes) was not disturbed, maintaining the communicating and collateral branches intact. In group II (right limb), it was separated microsurgically from each other for 3 cm. Intravenous pressure was measured at 5, 15, 30, and 60 minutes after tourniquet release. The values of group II at 30 and 60 minutes were significantly lower (p<0.01) than those of group I. Ten days after flap elevation, the mean survival area of group I (95%) and group II (100%) was not significantly different. Histological examination of the vascular pedicle showed the saphenous veins in group II were more dilated than those of group I. These findings suggest that venous retrograde return in reverse-flow island flaps can be achieved more easily through a "direct incompetent valves route" than through a "circuitous communicating and collateral bypass route."

Full-length phrenic nerve transfer by means of video-assisted thoracic surgery in treating brachial plexus avulsion injury

Phrenic nerve transfer has been widely used in treating brachial plexus avulsion injury. However, the present method crosses the thoracic part of the phrenic nerve, and nerve graft is needed, resulting in a long period of regeneration and partly irreversible muscle atrophy. We present our early experience of using video-assisted thoracic surgery to harvest a full length of phrenic nerve for transfer. Fifteen patients (mean age, 28 years) were treated. The thoracic part of the phrenic nerve was freed by means of video-assisted thoracic surgery and taken out of the thoracic cavity, and a full-length phrenic nerve was transferred to the musculocutaneous nerve to recover elbow flexion. The patients were followed. Another 29 patients with long-term follow-up who underwent traditional cervical phrenic nerve to musculocutaneous nerve transfer in our institute between 1994 and 1997 were selected. The period of newborn potential appearing in the biceps and the period for biceps to achieve M3 between two groups were compared. The operation was safe and no complications occurred. The additional length of phrenic nerve was 12.3 +/- 4.5 cm. Eleven patients received sufficient follow-up. Eight patients achieved biceps recovery to M3 (elbow flexion against gravity), and mean time was 198.8 +/- 36.0 days, much earlier than that of the traditional method (p < 0.01). Pulmonary function recovered to the preoperative level 9 months after operation. This new method is safe and minimally invasive. The result of full-length phrenic nerve transfer is much better than that of the traditional method. It obviously shortens the time required for nerve reinnervation, and offers a promising method for patients who have had a long interval from injury to operation and for forearm muscle reconstruction by phrenic nerve transferred to the median nerve or combined with free-muscle transfer.

Applying transfer of trapezius and/or latissimus dorsi with teres major for reconstruction of abduction and external rotation of the shoulder in obstetrical brachial plexus palsy

To evaluate the effects of transfer of the trapezius and/or latissimus dorsi with the teres major for treatment of dysfunction of the shoulder in obstetrical brachial plexus palsy (OBPP), 34 patients with paresis of the abductors and external rotators, as well as co-contraction of the adductors in abduction, who had undergone reconstructive operations, were followed-up for at least 1 year. Of these, transfer of the latissimus dorsi with attached teres major to the insertion of the infraspinatus (single procedure), was performed in 25 cases, and transfer of both latissimus dorsi with teres major and trapezius (to the humerus) in nine (combined procedure). Gilbert's grading system was used for evaluation. The results showed that in spite of improvement of external rotation in most of the cases, abduction was improved in only 13 of the 25 cases with a single procedure, and that eight of nine cases with a combined procedure gained improvement of both external rotation and abduction. These results indicated that, for improvement of both abduction and external rotation of the shoulder in OBPP, transfer of the latissimus dorsi with the teres major can be performed only when abduction is > or =90 degrees; otherwise, transfer of the trapezius should be added.

Phrenic nerve conduction study in patients with traumatic brachial plexus palsy

Phrenic nerve conduction studies were performed to assess the ipsilateral nerve in 100 patients with traumatic brachial plexus palsy. Open exploration and intraoperative recordings of somatosensory evoked potentials and nerve action potentials were used to confirm the level of root lesions. The relationship between C-5 preganglionic root lesion and the functional integrity of the ipsilateral phrenic nerve was examined. The phrenic nerves were normal in 80 cases, partially injured in 7, and severely injured in 13. We found C-5 preganglionic root lesions in 13 (100%) patients with severely injured, 5 (71.4%) with partially injured, and 24 (30%) with normal phrenic nerves. This correlation suggests phrenic nerve conduction study is a useful tool in the diagnosis of C-5 preganglionic root lesions in patients with traumatic brachial plexopathy.

[Culture of human muscle satellite cell]

OBJECTIVE

To investigate the biological characteristics of human muscle satellite cell cultured in vitro.

METHODS

Human muscle satellite cells were obtained from skeletal muscle biopsies of six patients during corrective orthopedic surgery, cultivated in growth medium for ten days, then in differentiation medium for additional five days. Human satellite cells were identified with monoclonal antibody against desmin. Cells were observed under phase contrast microscopy.

RESULTS

Human muscle satellite cells proliferated in growth medium, and fused to form myotubes in differentiation medium. After 24 hours in differentiation medium, the confluent satellite cells began to fuse actively and achieved the top level at 72 hours.

CONCLUSION

Human muscle satellite cell can proliferate and differentiate in appropriate culture condition. Immunocytochemical detection of desmin is the effective early method to determine satellite cell.

Lowest number of brachial plexus nerve roots required for maintaining normal limb function--an experimental study

Rat models with different division of nerve roots of the brachial plexus were designed to assess whether single or two nerve roots of the contralateral normal brachial plexus can be divided as donor nerves in treatment of brachial plexus root avulsion. Two hundred and fifty-two SD rats were randomly divided into 13 groups, i.e. five groups with single nerve root division, seven groups with two nerve roots division, and one group with three nerve roots division. Post-operative evaluation by electroneurophysiology and muscular histology was performed at two weeks and two months. Results showed that in groups with single nerve root division, the experimental limb function did not show an apparent damage; in groups with non-neighbouring two nerve roots cutting, it did show a harmful repercussions on the limb at two weeks, but most of them recovered to normal at two months; in groups with neighbouring two nerve roots division and with non-neighbouring three nerve root cutting, the limb function showed a persistent damage. In conclusion, division of nerve root alone or even non- neighbouring two nerve roots of the brachial plexus did not affect the forelimb function of the rat permanently.

[Effect of electroacupuncture on mRNA expression of NGF and IGF-1 in injured nerve]

OBJECTIVE

To investigate the effect of electroacupuncture on mRNA expression of NGF and IGF-1 in injured nerve.

METHODS

Sciatic nerve injury model was established by transection of right side sciatic nerve in 90 male SD rats, which were randomly divided into two groups. The experimental group was treated with electroacupuncture, no treatment in the control group. The distal part of the injured nerve was harvested after 1, 2, 4, 6 and 10 weeks of operation and stored in the liquid nitrogen. The total RNA was extracted by the TRIzol reagent. Reverse transcriptase-polymerase chain reaction(RT-PCR) was used to detected the mRNA expression of NGF and IGF-1.

RESULTS

The mRNA expression of NGF in the experimental group was increased quickly from the second week, and reached to highest level in the fourth week. It was much higher than that of the control group (P < 0.05). Then it began to decline in following time and approximately reached to the level of the first week after 10 weeks of operation. The mRNA expression of IGF-1 in the experimental group was remarkably increased in the second and fourth week, and which was much higher than that of the control group respectively(P < 0.05). Although the mRNA expression of IGF-1 after 10 weeks of operation in the experimental group was higher than that of the control group, but there was no significant difference between the two groups(P > 0.05). There was linear correlation in the fourth week between mRNA expression of NGF and IGF-1 in the experimental group.

CONCLUSION

The mRNA expression of NGF and IGF-1 can be elevated in injured nerve at early stage interfered with electroacupuncture.

[Application of silks as scaffolds for three-dimensional culture of chondrocytes]

OBJECTIVE

To observe the effects of silks on attachment, shape and function of chondrocytes cultured in vitro.

METHODS

The silks from silk worm cocoons were digested by trypsin and coated with polylactic acid to from three dimensional scaffolds for rabbit rib chondrocyte culture. The growth and shape of chondrocytes were observed with phase contrast microscopy, scanning electron microscopy.

RESULTS

The chondrocytes were adhered to silks slowly after chondrocytes were seeded into silk scaffolds and cells fixed on silks well 1 or 2 days later. Cells began to proliferate after 3 days and multiplicative growth was observed on the 6th day. Microholes of silk scaffolds were filled with chondrocytes 2 weeks later. Scanning electron microscopy showed that there was a lot of extracellular matrix surrounding cells.

CONCLUSION

Silks are ideal for attachment, growth and function maintenance of chondrocytes, and silks can be used as scaffolds for chondrocytes in three dimensional culture.

The donor foot in free toe or joint transfers

Eighty-four cases of free second toe, multiple toe or second metatarsophalangeal joint transfers were studied by case review and follow-up. The function of the donor foot had recovered completely within 6 months in 89% of patients. The wounds on the donor foot healed in 2-3 weeks in 90% of patients. Slight numbness on the dorsal aspect of the donor foot, intolerance to cold, mild reduction in push-off, scar tenderness and pain or swelling occurred in only a few patients and generally were not considered of significance. Multiple toe transfers created more donor problems in terms of healing and appearance. Some foot deformities with plantar callosities were observed at long term review. However, all patients were capable of work and normal activities.

[Experimental evaluation of low-dose aspirin used in microvascular surgery]

OBJECTIVE

To evaluate the effect of low-dose aspirin on the deposition of platelet at the anastomotic site and the function of coagulation system in order to provide experimental data for clinical use.

METHODS

(1) Twenty-eight SD rats were divided into experimental group (n = 21) and control group (n = 7), aspirin were administered through a catheter placed in the femoral vein in dose of 4 mg/kg in the experimental group and the same dose of normal saline in the control group. The experimental group was subdivided into 3 groups, with 7 rats in each group, according to survival time of 24, 48 and 72 hours after dose. Samples of 4 ml blood were taken by heart puncture from each rat to investigate the maximal platelet aggregation rate(MAR), prothrombin time(PT) and kaolin partial thromboplastin time(KPTT). (2) Sixteen New Zealand White rabbits were divided into experimental and control group, 8 rabbits in each group. Drugs were given in the same way. Forty-eight hours later, the bilateral femoral arteries of each rabbit were exposed and arteries between inguinal ligament and the origin of the superficial epigastric arteries were transected and end-to-end anastomosis was completed with interrupted suturing technique. Fifteen and 120 minutes after the recovery of blood flow, the left and the right vessels containing anastomotic sites were harvested respectively and treated with 125I-labeled anti-GP IIb/III a antibody (SZ-21) using radioimmunobinding method. The radioactivities of the anastomosed vessels were measured.

RESULTS

The KPTT in the experimental group was longer than that of the control group at 24- and 48-hour group, the mean percentages of increase were 42.56% and 35.33% respectively, and there were very significant differences between the experimental and control group in 24-hour group (P < 0.001). The PT value in experimental group was longer than that of the control group, but there was no significant difference (P > 0.05), and the maximal aggregation rate of platelet in the experimental group was significantly lower than that of the control group after 72 hours (P < 0.001). The radioactivity of the anastomosed arteries in the experimental group were significantly higher than that of the control group (P < 0.001) at 15 minutes after the recovery of blood flow, the mean percentage of increase was 110%.

CONCLUSION

Low-dose aspirin can significantly affect the function of the intrinsic coagulation system, prevent the aggregation of platelets, but no effect on the function of the extrinsic coagulation system. On the other hand, it can also increase the deposition of platelet on the anastomotic sites after end-to-end anastomosis, especially in the early stage when it is intravenously injected, but it is strong enough to cause thrombosis at the anastomotic sites. The effects of low dose aspirin on the coagulation system are inconsistent with its local effects on anastomotic sites.

[Experimental study of mechanism and measures of prevention and treatment of hypothermal vasoconstriction]

OBJECTIVE

To investigate the mechanism and to explore the measures of prevention and treatment of hypothermal vasoconstriction.

METHODS

By the techniques of endothelial cell culture and scanning electron microscopy, and vasomotor functional test of isolated vascular vessels, the relation of hypothermal vasoconstriction and the release of endothelium-derived contractile and vasodilative factors were observed.

RESULTS

Hypothermia obviously induced vasoconstriction of isolated vascular vessels, whether endothelium was intact or removed, the lower the temperature, the higher the vascular tension. Removal of endothelium could decrease the effect of vasoconstriction by hypothermia. The conditioned medium of bovine aortic endothelial cell could induce significantly vasoconstriction of isolated rat common neck arterial ring in hypothermia. It indicated that the bovine aortic endothelial cells secreted contractile factors into the medium. Reheating to 37 degrees C or vasodilator or reheating plus vasodilator did not obviously influence the hypothermia-induced vasoconstriction within 2 hours. When reheating to 50 degrees C, vascular tension was decreased, but only changed in range of 28% to 42%.

CONCLUSION

Hypothermia vasoconstriction is relative to vasoconstrictor factors secreted by endothelium. Reheating to 37 degrees C or vasodilator does not antagonize the constriction of vascular vessels. Reheating to 50 degrees C only partially eliminates the constrict effect of blood vessels, so the prevention of hypothermia vasoconstriction should be emphasized.

Vascular anatomic variations in second toe transfers

To devise a new classification of vascular variations in second toe transfer we analyzed the anatomic details of the first dorsal metatarsal artery in 304 cases of second toe transplantation and the venous structure in 200 cases. According to location, the arterial vascularity was classified as superficial (18% of cases), intramuscular (54%), inframuscular (23%), and absent (5%). According to diameter, it was classified into large (16%), medium (64%), and small (20%). Based on branching pattern, the artery was classified into ramifying type (88%), main trunk (4%), and fine branch type (8%). The venous drainage of the second toe was categorized as greater saphenous vein main trunk type, greater saphenous vein fine branch type, dorsal digital vein main trunk type, and dorsal digital vein fine branch type. Variations of the first dorsal metatarsal artery are common. Classification should be done according to its location, diameter, and branching pattern at the toe web. Regardless of location, big vessels entering the second toe are the most important attribute for successful outcome.

Fibrillation potential amplitude to quantitatively assess denervation muscle atrophy

Denervated muscle fibers exhibit spontaneous, repetitive single muscle fiber discharges and display fibrillation potentials detectable by electromyography. To explore the changing pattern of fibrillation potential amplitude after peripheral nerve injury and its relationship to the degree of muscle atrophy, fibrillation potential amplitudes were recorded on completely denervated biceps brachii of 173 patients with brachial plexus injury. Biceps brachii biopsies were taken at the same sites as the electromyogram recordings in 63 patients. The biopsies were analyzed by ATPase staining and the cross-sectional areas of fast and slow-twitch fibers were calculated. We found that the fibrillation potential amplitude and the cross-sectional areas of denervated muscle decay over time (P < 0.05), and both correlate negatively with denervation time (P < 0.01-0.05) within the first 15 months. The fibrillation potential amplitude correlates positively with both type I and II fiber cross-sectional areas (P < 0.0005-0.01). Our results show that fibrillation potential amplitude is closely correlated with muscle fiber size during the first 15 months after nerve injury, and it may therefore serve as a convenient index to evaluate quantitatively the degree of atrophy of denervated muscles. Electromyographic studies thus may help in designing treatment strategies.

Classification of impairment of shoulder abduction in obstetric brachial plexus palsy and its clinical significance

Shoulder abduction was studied in 25 cases of obstetric brachial plexus palsy (OBPP). According to muscle function, electromyographic features and X-ray examination, impairment of shoulder abduction could be classified into dynamic, resistant or combined types. Five cases were the dynamic type, which was characterized by paralysis of the shoulder abductors. Fifteen cases were categorized as the resistant type, with contracture of the subscapularis muscle, co-contraction of latissimus dorsi and teres major muscles and secondary disorders of the shoulder joint. Five cases were classified as the combined type in which there were both dynamic and resistant factors. Appropriate management and surgical procedures in the shoulder affected by OBPP depend on the pathological classification.

[Immunohistochemical study of S-100 protein in degenerative nerve after different pathological brachial plexus injuries]

OBJECTIVE

To explore the regularity of the change of S-100 protein in degenerative nerve after different pathological brachial plexus injuries.

METHODS

Eighty SD rats were randomly divided into two groups, right C5, C6 preganglionic injury, and postganglionic injury. The distribution and content of S-100 protein in distal degenerative nerve were detected after 1, 2, 3 and 6 months of injury by immunohistochemical methods.

RESULTS

The S-100 protein was mainly distributed along the axons. The S-100 protein positive axons of each time interval decreased after operation, with significant difference from normal nerves (P < 0.01). There was no statistically significant difference among 1, 2, 3 and 6 months group (P > 0.05). The S-100 protein stain of postganglionic group was negative.

CONCLUSION

In preganglionic injury, the functional expression of Schwann's cells in the distal stump keeps at a certain level and for a certain period. Since Schwann's cell has inductive effect on nerve regeneration, it suggests that the distal nerve stump in preganglionic injury can be used as nerve grafts.

[Experimental study of morphology and electrophysiology on denervated skeletal muscle]

OBJECTIVE

In order to provide the scientific basis to find out a practical and effective method to evaluate the degree of muscle atrophy and a better method of prevention and treatment of skeletal muscle atrophy.

METHODS

Forty-two adult Spray-Dawley rats were used and the model of denervated gastrocnemius muscle was established by cutting off the tibial nerve. The muscle wet weight, diameter and cross section area of myocyte were measured. The motor end-plate, fibrillation potential amplitude and frequency of denervated skeletal muscle were observed.

RESULTS

The muscle wet weight rapidly reduced within 4 weeks. Afterwards, it maintained about 30 per cent of normal value, and the diameter and cross section area of myocyte progressively reduced. The motor end-plate slightly changed within 4 weeks, but its degeneration accelerated in 6 weeks and disappeared after 16 weeks. The fibrillation potential amplitude was maximum at 2 weeks and it progressively reduced after 12 weeks of muscle denervation. The changes of amplitude and frequency were consistent with the degeneration of end-plate.

CONCLUSION

The muscle wet weight, diameter and cross section area of myocyte, fibrillation potential amplitude and frequency could be considered as the morphological and electrophysiological indexes of muscle atrophy degree. It's suggested that the repairing operation of peripheral nerve should be performed before the disappearance of motor end-plate.