Age-related changes of the cochlear lateral wall [stria vascularis] in the guinea pigs: an ultrastructural study

It is current opinion that the morphological changes in the stria vascularis and acquired hearing impairment appear to be the most prominent anatomic characteristic of aged human cochlea. The stria vascularis generates positive endocochlear potential and secretes endolymph which contains high concentration of potassium. Both of them are essential for normal sound transduction carried out by hair cells. Is to compare between the structure of stria vascularis in adult and senile guinea pigs, in an attempt to explain impairment of transduction of sound in old age [presbyacusis]. Cochleae of guinea pigs were extracted and processed to semithin and ultrathin sections, stained, examined and photographed. The senile stria vascularis showed herniations or protrusions from the luminal surface with blebs formation. Some marginal cells were vacuolated with pyknotic nuclei. The majority of mitochondria appeared fragmented, or swollen with disrupted cristae. However, the tight junctions between these cells were preserved. The most apparent ultrastructure alteration with age was loss of basolateral infolding with reduction of interdigitation between the marginal and intermediate cells. Dramatic decrease of the amount of melanin pigments with abundant myelin like figure was clearly noticed. The basal lamina of the strial blood capillaries was thickened and folded in some areas. The endothelial cells remained intact; however pericytes were not observed. The present findings proved that there were marked structural changes in the stria vascularis of senile guinea pigs, suggesting that these might be one of the causes of acquired hearing impairment in old age

human interossous membranes anatomical and histological study

This study was performed to describe anatomical details and histological picture of interosseous membrane [IOM] of forearm as well as crural interosseous membrane [IOM]. The results showed that IOM of forearm was a complex structure joining radius and ulna and was formed mainly of collagen fibers with some elastic fibers. A proximal well- defined band was also found in about half of the specimens. Two major openings and two to three secondary openings were observed. As regards crural interosseous membrane, it was found to be whitish glistening membrane stretched between both crural bones and was formed mainly of collagen fibers, while elastic fibers could not be detected. Two major openings were observed as well as two to three secondary openings along the length of membrane were found

Study of the effect of food additives on the structures of the lung and kidney of albino rats

Butylated hydroxytoluene [BHT] is a well known food additive, as it prevent fat rancidity, as well as antioxidant and is used in several clinical purposes. Forty male rats were used to study the effect of BHT on the kidney and lung. The animals were divided into three groups. Animals of group I served as controls. Animals of group II were given BHT orally 25 mg/Kg BW daily for 6 weeks and those of group III were given BHT orally daily [double the dose] 50 mg/kg BW for 6 weeks. The kidney showed changes in the glomeruli in the form of thickening and irregularity of Bowman's membrane with hypertrophy of its endothelial lining and proliferation of parietal epithelial cell on the expense of urinary space. There was also change in the proximal tubules in the form of thickening of tubular basement membrane with loss of normal basal in folding together with increased vacuolation and lysosomal content. There was also loss of normal longitudinal arrangement of mitochondria. As regards the lungs, they showed thickening of the alveolocapillary and interalveolar septum with narrowing of the alveolar space. There was evidence of damage of type I pneumocytes and proliferation of type II which dedifferentiate into newly formed type I to regenerate the respiratory epithelium and to compensate the parenchymal damage. Extensive collagen deposition and fibrosis was clearly seen. BHT is a useful food additive used as antioxidant in many purposes. However, the dose used to study the effect of the abuse of BHT as a food additive has some side effects, especially on the lung and kidney. So, the study recommended the usage of BHT as a food additive in the lowest possible dose especially in children

protective effect of L-Carnitine, desferriox-amine, and verapamil on mitigation of Epirubicin-induced cardiomyopathy in adult albino rats

The present study was conducted on 70 adult albino rats of both sexes [180 +/- 20 g body weight] divided into nine groups: Group I [negative control group], group II [isotonic saline 0.5 ml intraperitoneal, i.p.], group III [L-carnitine 50 mg/kg i.p.], group IV [desferrioxamine 90 mg/kg i.p.], group V [verapamil 10 mg/kg i.p.], group VI [epirubicin 2.25 mg/kg i.p.], group VII [epirubicin-L- carnitine], group VIII [epirubicin-desferrioxamine] and group IX [epirubicin-verapamil]. At the end of the experimental period [12 weeks], blood pressure and heart rate were measured and blood samples were collected for investigating serum aspartate aminotransferase [AST], lactic dehydrogenase [LDH], creatine phosphokinase [CPK], creatine phosphokinase isomer [CPK MB], heart fatty acid binding protein [HFABP], glutathione peroxidase [GSH] and malondialdehyde [MDA]. Cardiac tissue samples were taken for estimating the tissue levels of MDA and GSH. Furthermore, a histopathological examination of the heart was carried out

Effects of administration of alpha interferon in mice during pregnancy, on the livers of the mothers and offsprings. A histological and ultrastructural study

In this work, five non-pregnant mice were used as a negative control group to study the normal basic structure of the liver; two groups of pregnant mice, each included ten animals, were also used. In the first pregnant group, the animals were injected subcutaneously with alpha interferon at a daily dose of 150,000 IU/kg b. wt. from the first day of pregnancy till the time of delivery; while, in the second pregnant group, the animals were injected by an equivalent amount of sterile water for the same period of the first group. At the day of delivery, half of the mothers of each group were sacrificed, while the other half were left to suckle the offsprings. From the offsprings of each group, six pups were randomly chosen to be sacrificed after one day and another six after three weeks of delivery. From all the studied animals, liver samples were taken and processed for light and electron microscopic examination

Some of the toxic responses accompanying both short and long term administration of mycophenolate mofetil in adult albino rats

Some of the toxic hazards associated with short- and long-term administration of mycophenolate mofetil [Cellcept] were evaluated in this study. It was conducted on 36 adult albino rats of both sexes [180 +/- 20 g body weight]. They were divided into four main groups: A negative control group [group I], positive control groups [IIa and IIb] received distilled water orally and Cellcept groups [III and IV] received Cellcept 72 mg/day and 36 mg/day orally for one and three months, respectively. At the end of the study, blood samples were collected for the determination of Hb concentration, red blood cells count [RBCs], white blood cells count [WBCs] and platelets counts, blood urea nitrogen [BUN], serum creatinine, uric acid, potassium [K+], sodium [Na+] and calcium [Ca++] levels. Furthermore, a histopathological examination of the small intestine and the kidneys was carried out

effects of aging and vincamine administration on the structure of the rat pineal gland

The pineal tissue was studied in four groups of male albino rats: a group of adult rats, a second group of senile rats, the third and fourth groups consisted of senile rats which were injected with the vehicle of vincamine drug and the drug itself respectively in their old adult stage of life. The investigations showed that the adult pineal gland was characterized by high cellularity, and two types of cells were observed; the pinealocytes and the glial cells. The pinealocytes constituted the majority of cells and were of two types; light and dark, while the glial cells were fewer, smaller with ramifying thin processes. Using electron microscopy, the cytoplasm of light pinealocytes was noted to be rich in secretory organelles, containing euchromatic nuclei and with prominent nucleoli. On the other hand, the dark pinealocytes appeared more electron dense with less amount of organelles and heterochromatic nuclei in their cytoplasm. Glial cells appeared as small cells of high electron density with thin ramifying processes full of filaments and large dark heterochromatic nuclei. Senile pineal glands of both the second and third groups showed marked decrease in the cellularity, irregularity and in folding of the nuclei were a prominent feature. By electron microscopy, the light pinealocytes showed marked decrease in the amount of secretory organelles together with the appearance of lipid droplets, lysosmes, and dense bodies. In addition, the nuclei of this type showed deep indentations. The cytoplasm of dark pinealocytes showed abundant multivesicular bodies and deeply indented heterochromatic nuclei. The glial cells had to same structure as in the adult glands. The study of the pineal tissue in senile animals which were previously treated with vincamine showed marked increase in the cellularity, and the majority of cells were of the light variety. By electron microscopy, the cells had the picture of highly active cells. The light pinealocytes were rich in mitochondria and secretory organelles such as dilated cisterns of endoplasmic reticulum, and Golgi apparatus. On the other hand, lysosomes, lipid droplets and dense bodies were hardly observed. The nuclei of these cells were either oval or irregular and of the euchromatic appearance. The dark pinealocytes showed secretory organelles in their cytoplasm but less abundant than those observed in the cytoplasm of the light cells. The nuclei, although of high electron density, yet they were of the euchromatic appearance. According to the present investigation, it could be concluded that the currently discussed drop in melatonin synthesis in old age is due to regressive changes in the morphology of the gland. Moreover, the use of vincamine may prevent or delay the appearance of such degenerative changes. This may preserve the melatonin synthesis in the body and consequently delays the aging process