Response of rabbit skeletal muscle to tibial lengthening

Background Experimental and clinical studies have provided knowledge regarding osteogenesis during limb lengthening. However, response of skeletal muscle to limb lengthening is not fully understood, especially as concerns histogenesis. We studied the morphological response of rabbit skeletal muscle to limb lengthening. In this study, we investigated proliferation of satellite cells, responsible for generation of new myonuclei, during limb lengthening. Methods Tibialis anterior muscles of young and adult rabbits were subjected to lengthening at a rate of 0.mm twice per day for 20 days. After lengthening, muscle wet weight was measured to assess skeletal muscle growth, then proliferating cell nuclear antigen was measured. Immunostaining was performed to analyze proliferating cells in the proximal, middle, and distal portions of the muscle belly and the musculotendinous junction. Results Muscle wet weight increased significantly after lengthening both in adult (0.4g) and young (0.1g) rabbits. Satellite cells showed proliferation in response to lengthening. In adult rabbits, satellite cell proliferation increased along the entire lengthened muscle to a similar degree (from 7.1% in the middle portion to 8.6% in the musculotendinous junction). In young rabbits, proliferation was greater in the musculotendinous junction (4.8%) than that in other muscle portions (2.3% in the middle and distal portions, and 2.4% in the proximal portion). In adult rabbits, the rate of increase in satellite cell proliferation was 1780% in the middle portion to 2860% in the musculotendinous junction, whereas the rate was between 210% in the middle portion and 290% in the distal portion in young rabbit. The rate of increase in cell proliferation by lengthening was higher in adult muscle than that in young muscles as well as satellite cell proliferation. Conclusion These findings indicate that limb lengthening promotes muscle growth in both young and adult rabbits.     

Thermal effect of illumination on microsurgical transfer of free flaps: experimental study and clinical implications

The light source of a modern operating microscope gives a clear operative field, but the possibility of thermal impairment by the strong light is substantial. We aimed to elucidate the potential risk of such strong light on transfer of free flaps and the optimal application of light. First, the thermal effect of clinically used microsurgical illumination was examined by direct irradiation of a thermometer. Secondly, the thermal influence on living tissue of microsurgical light was evaluated using a model of vascularised and non-vascularised pedicled groin flaps in rats. Thirdly, the influence of strong light on the transfer of free flaps was investigated using a model of a free groin flap in rats. Fourthly, histological alteration was investigated by a light microscopy and scanning electron microscopy. With direct irradiation of a thermometer, temperatures reached values in excess of 80 degrees C with maximal xenon light illumination from 20 cm. The mode of illumination significantly influenced the results of free flaps. Prolonged irradiation of the vascular pedicle in particular resulted in an increase in the number of failures, supposedly caused by venous occlusion. Bright illumination contributed to efficient microvascular procedures, but we confirmed its potential risk. Our findings may benefit all surgeons engaged in transfer of free flaps, as potential impairment caused by excessive operative irradiation is prevented simply by recognition of its harm.     

Low-grade myofibroblastic sarcoma of the palm.

We report here a case of an unusual spindle cell tumour of the palm with myofibroblastic differentiation, which was surgically excised. Histologically and immunohistochemically, it was a low-grade myofibroblastic sarcoma. After 25 months follow-up the patient is well and free of recurrence.     

Matrix metalloproteinase-9 in spontaneously hypertensive hyperlipidemic rats.

The presence of hypertension and hyperlipidemia accelerates atherosclerosis and increases the risk of ocular disease. Since there were few rat models for atherosclerosis, spontaneously hypertensive rats (SHRs) and spontaneously hyperlipidemic rats (HLRs) were crossbred to obtain a new model: the spontaneously hypertensive hyperlipidemic rat (SHHR). Matrix metalloproteinases (MMPs) play an important role in ocular degeneration. The purpose of this study is to investigate changes in the MMP activities in vitreous and plasma as well as MMP expression in the retinas of SHHRs, which served as a model of vascular degeneration. We used 8-month-old Wistar-Kyoto (WKY) rats and Sprague-Dawley (SD) rats, SHRs, HLRs, and SHHRs. The MMP-2 and MMP-9 activities in plasma and vitreous were examined by zymography. The mRNA expression of MMP-2, MMP-9, and tissue inhibitor of metalloproteinases-3 (TIMP-3) in retina was examined by quantitative PCR. The localized expression of MMP-9 in the retinas was examined by immunostaining. The MMP-9 activity increased significantly in SHHRs compared with all other rats. MMP-9 was observed mainly at the superficial layer of the retina on immunostaining. The MMP-2, MMP-9, and TIMP-3 mRNA in retina was not significantly different in SHHRs as compared with all other rats. Increased MMP-9 activity in vitreous was influenced more intensely from plasma than retina because there was no change in MMP-9 expression in retina, and MMP-9 immunostaining was observed mainly at the surface of the retina, where blood vessels are present. In this study, the complications of hypertension and hyperlipidemia induced increased MMP-9 activity in vitreous and plasma. It is therefore suggested that MMP-9 may be involved in causing this result and in the development of retinal disease.     

A diagnosis of hepatic diseases by determination of L-glutamate dehydrogenase

Journal of Gastroenterology -     

Disruption of the blood-brain barrier caused by nonionic contrast medium used for abdominal angiography: CT demonstration

We describe a case of disruption of the blood-brain barrier (BBB) by nonionic, low osmolality contrast medium after abdominal angiography. One plausible explanation of this event is that acute hypertension during angiography may have increased the BBB permeability, allowing the contrast medium to leak across it.     

Prophylaxis of Postoperative Biliary Stasis: A Retrospective and Prospective Study

Postoperative biliary stasis is a common state before the onset of postoperative acute cholecystitis. In order to study its characteristics and methods of prophylaxis, we examined the frequency of biliary stasis and postoperative recovery of gallbladder contractility ultrasonographically from the 2nd to the 28th postoperative day in 43 esophagectomy cases. A retrospective study in 17 patients revealed a high incidence of biliary stasis during the early postoperative period and improvement by the initiation of enteral nutrition. Furthermore, the contractility of the gallbladder recovered remarkably soon after the operation. This first randomized prospective study concerning prophylaxis of biliary stasis in 26 patients showed that postoperative biliary stasis was prevented by early initiation of enteral nutrition.     

Lymphoid neoplasms in chicken flocks free of infection with exogenous avian tumor viruses.

More than 4,500 breeding female chickens of nine inbred lines maintained under specific-pathogen-free conditions to approximately 500 days of age were studied. Routine monitoring and special assays indicated that they were free of infection by exogenous viruses of the leukosis-sarcoma and the reticuloendotheliosis groups. Some birds were maintained free of Marek's disease (MD) virus infection in plastic isolators, and others were maintained in conventional chicken houses and vaccinated with the herpesvirus of turkeys to prevent the lesions of MD. Ten birds bearing lymphoid tumors were observed in two sublines of one line of chickens known to produce embryos that spontaneously produce Rous-associated virus, type 0 (RAV-O), an endogenous virus of the chicken. Four tumors were found in chickens of one subline maintained free of MD virus infection in isolators. These tumors did not involve the bursa and had some histologic features different from those typical of lymphoid leukosis. Six tumors were found in chickens of the other subline that were vaccinated to prevent MD; these tumors involved the bursa and were typical of lymphoid leukosis but not MD. These results suggest that two types of tumors may have been observed. The fact that DNA extracted from both types of tumors did not contain exogenous lymphoid leukosis virus sequences confirms the virologic evidence that exogenous viruses were not involved. The fact that endogenous viral sequences were not increased in copy number suggests that the endogenous virus RAV-O did not directly induce the tumors. Two birds with tumors not involving the bursa were found alive, and transplantable lymphoid tumors were developed. These tumors were of T-cell origin rather than of bursa cell origin as would be expected of lymphoid leukosis. These are the first reported lymphoid tumors that have been observed in the absence of known exogenous tumor virus infection in chickens. Our evidence suggests that the endogenous virus RAV-O did not play a primary role in the induction of these tumors.     

Preoperative ultrasonography screening for liver metastases of patients with colorectal cancer

The clinical value of preoperative ultrasonography in screening for synchronous liver metastases was prospectively evaluated in 338 patients with colorectal cancer. Synchronous liver metastases were observed at laparotomy in 11.5% (39/338) of the patients. The liver metastases had been found by preoperative ultrasonography in 30 patients and missed in nine. The overall accuracy rate, sensitivity and specificity, and the positive and negative predictive values of this modality were 0.970, 0.769, 0.997, 0.968 and 0.971, respectively. In detecting liver metastases, the results were superior to those of biochemical blood tests and measurements of carcinoembryonic antigen serum levels. The accuracy of the ultrasonography was also superior to that of these other tests combined. The results indicate ultrasonography to be an indispensable preoperative examination for patients with colorectal cancer.