Histological study of the effects of extensive freeze injury on the rabbit aorta

Cryopreservation of blood vessels has become one of the key techniques to make up the limited sources of fresh blood vessels. But cryopreservation methods do not adequately preserve complex natural or engineered multicellular tisses. When lesions are produced by localized freezing of the aorta, necrosis is present throughout the full thickness of the tunica media of tunica media as well as in the endothelium. The response of the vessel wall varies according to the extent of endothelial denudation and the period of freeze injury. From this point of view, this study was designed to investigate the histological effects of extensive freeze injury on the rabbit aorta. The abdominal aorta of twenty-five adult male rabbits were used in this study. Five normal adult male rabbits were used as a control [group I]. The remaining twenty rabbit aorta were exposed to extensive freeze injury by a 12-mm aluminium bar, cooled down to the temperature of liquid nitrogen and placed on the exterior of the abdominal aorta [infrarenal segment] for I min. Freeze injury was done at 1, 3, 14 days and one month [5 rabbits / time point], corresponding to groups II, III, IV, V respectively, the aortae were excised, fixed by buffered formol saline 10%, paraffin sections were prepared and stained by haematoxylin and eosin [H. and E.] to demonestrate the general architecture of the aorta, orceinfor elastic fibers demonstration in the wall of the aorta and masson's trichrome to illustrate the collagen fibers and smooth muscle cells [SMC] in the whole aortic wall. Group II showed injured surface with desquamated denuded endothelium covered with blood elements in a single layer. The internal elastic fibers were damaged at injury site. Group III showed regenerating endothelium at the edge of the injury zone. Proliferating intimal cells was observed. Group IV showed thickened and elevated intima at the injury zone with migrating smooth muscle cells from the media to the intima. Smooth muscle cells populated the subendothelial space of the injured zone under the regenerated endothelium. Group V showed the tunica media had an area of smooth muscle cells destruction with cellular debris and homogenous smooth degeneration. The intima showed full restoration of endothelial monolayer in the zone of injury. After extensive freeze injury, complete re-endothelialization of the denuded surface and SMC regeneration in the subendothelial space occured, resulting in endothelial myointimal thickening. On the other hand, irreversible changes in the smooth muscle cells of the tunica media were noticed

Histological and histochemical study of effects of arsenic on the liver of adult male rabbits

Arsenic is an environmental toxicant and a human carcinogen. Epidemiology studies link human arsenic exposure to various diseases and cancers, including liver diseases and hepatocellular carcinoma. From this point of view, this study is designed to investigate the effects of arsenic histologically and histochemically on the liver of adult male rabbits. Twenty adult male rabbits were used and divided into four groups. Each group consisted of five rabbits, one group used as a control given an equivalent volume of distilled water and three groups given sodium arsenite in distilled water for 6, 12 and 18 weeks respectively. Paraffin sections from all groups prepared and stained by haematoxylin and eosin, and periodic acid-schiff. Histological and histochemical changes in arsenic groups were marked vacuolation of hepatocytes with focal areas of hepatocellular degeneration. Loss of hepatic architecture was also observed. Marked dilatation and congestion of the central veins and mononuclear cellular infiltration were obvious. Quantitative analysis of intracellular glycogen stores of all groups using image analyzing system revealed gradual significant depletion of intracellular glycogen stores. It was concluded that arsenic is a hepatotoxic agent in the adult male rabbits

Acute Guillain Barre Syndrome in childhood: clinical, electrophysiological and immunological study

Acute Guillain Barre Syndrome [acute GBS] is one of the leading causes of acute flaccid paralysis [AFP] in children. The syndrome has been recognized as a heterogeneous disorder with different subtypes, by clinical, electrophysiological and pathologic criteria. The disease may present with a wide variety of clinical presentations as well as prognostic outcome. The study was conducted on all children with acute GBS attending Alexandria University Children's Hospital during the period from September 2000 to September 2001 for the purpose of characterization of acute GBS in Egyptian Children and its relation to presumed infection with Cytomegalovirus [CMV] or Epstien-Barr virus [EBV]. All clinical, laboratory and electrophysiological data of the children with acute GBS who are admitted to the hospital during the period of the study were evaluated. Serum IgM titer against CMV and EPV were assessed and correlated with other patients'data. Thirty five children were admitted to the hospital during that period. Sixty age and sex matched healthy children were included as controls for studying IgM titre of EBV and CMV. Affected children were 22 boys and 13 girls. Their ages ranged between one and 10 years. Eight cases did not have preceding illness before the disease. The initial symptom was motor in 11 cases, sensory in 2 cases and mixed in 22 cases. Ascending paralysis was dominant in all cases except three who had descending paralysis. Only five cases did not exhibit severe pediatric GBS [grade 4 or 5] according to the functional grading system. Twenty nine cases exhibited the major electrophysiological type of acute inflammatory demyelinating polyneuropathy [AIDP]. Albuminocytologic dissociation was encountered in 25 cases. Two cases died in the acute phase, one was left with residual neurological deficit while the rest recovered completely. There was a statistically significant difference between cases and controls as regards the IgM titre against CMV virus [P < 0.05] while IgM titres against EBV were not statistically different from the control group. In addition children with presumed Prior CMV infection tended to be younger in their age significantly more than those with presumed EBV infection [r = 0.382, P = 0.003]. The only significant association was the relation between the type of initial symptoms versus the IgM titre against CMV and EBV where sensory symptoms were prominent more significantly among cases with presumed CMV infection than those with presumed EBV infection [P<0.005]. Acute GBS demonstrates diverse clinical, electrophsyiolgical and laboratory dilemma. Clinical and electrophysiological criteria remain the most important prognostic factors. Despite its initial grave presentation, early institution of therapy using intra-venous immunoglobulin [IVIG] or plasma exchange ensures dramatic recovery in most of cases. The underlying etio-pathologic mechanisms are still not properly understood. Their clarification might have its impact on better delineation of clinical presentations, outcome and prevention

Voice changes after thyroidectomy: role of external laryngeal nerve

To evaluate a technique to protect the external laryngeal nerve during thyroidectomy.Randomized controlled trial. Patients randomized into group A or B using closed envelops method. Alexandria university hospital is a teaching hospital. It is the referral center serving seven million people. Forty four consecutive patients admitted to Alexandria university hospital for thyroidectomy. Fourpatients had voice abnormalities on preoperative voice analysis. They were excluded. All patients underwent thyroidectomy. Group A had conventional mass ligature of the superior poleof thyroid gland while group B had individual ligation of the branches of the superior thyroid artery afteridentification of the external laryngeal nerve whenever possible. Abnormal readings on postoperative voice analysis and abnormal electromyogram of thecricothyroid muscles. Observers performing voice analysis tests were blinded as regards patient group. Postoperativeelectromyography of the cricothyroid revealed signs of nerve injury in five patients of group A but none in groupB. Multi-dimensional voice program, fundamental frequency range, fundamental frequency and maximum pressurelevel all showed significant postoperative change in group A but not of those in group B [level of confidence95%].Identification of external laryngeal nerve and/or ligation of the terminal branches of the superiorthyroid vessels seems to help prevent external laryngeal nerve injury

Electrophysiological evaluation of penile somatic nerve function in diabetic impotent patients

Penile non autonomic nervous function in 17 impotent diabetic patients were studied electrophysiologically, the methods used were dorsal nerve of penis [DNP] conduction velocity, and Bulbocavernosus reflex [BCR]. H Reflex and medial popliteal nerve conduction velocity were also included to assess lower limb nerve function as an indication of generalized neuropathy and radiculopathy. The same studies were performed on 8 normal volunteers. The Dorsal nerve of penis conduction velocity was found impaired in 11 patients [64.7%] either in an isolated form or as a part of generalized neuropathy. Two of the patients showing normal DNP conduction velocity demonstrated electrophysiological evidences of radiculopathy. The present study suggests that the abnormal non autonomic nervous function contributes to the pathogenesis of impotence and that the isolated autonomic neuropathy leading to impotence is rare