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Biomedical subjects

S S Ali

Publications and source records attributed to S S Ali.

At least 19 recordsLinked to original sources
PubMed1995

Aminoguanidine does not inhibit the initial phase of experimental diabetic retinopathy in rats.

We have previously shown that long-term administration of aminoguanidine, an inhibitor of advanced glycosylation product formation, reduces the extent of experimental diabetic retinopathy in the rat by 85%. In order to determine whether the residual retinopathy that developed despite aminoguanidine was attributable to advanced glycation endproduct formation, a time-course study was performed in three different groups of male Wistar rats: non-diabetic controls (NC), streptozotocin-diabetic controls (DC) and streptozotocin-diabetic rats treated with aminoguanidine HCL, 50 mg/100 ml drinking water (D-AG). Eyes were obtained at 24, 32, 44 and 56 weeks of diabetes/treatment duration and morphologic evaluation was done on retinal digest preparations. At 56 weeks, retinal basement membrane thickness was additionally measured. After 24 weeks of diabetes, the number of acellular capillaries was significantly elevated in DC (44.6 +/- 5.7/mm2 of retinal area, NC 19.6 +/- 4.9; p < 0.001) and increased continuously over time (DC 56 weeks 87.4 +/- 15.1; p < 0.001 vs DC24 weeks). In contrast, acellular capillaries in D-AG increased over the first 24 weeks and then remained constant for the rest of the study (D-AG 24 weeks 35.7 +/- 5.18; p < 0.01 vs NC 24 weeks and NS vs DC 24 weeks; D-AG 56 weeks 42.0 +/- 6.20; p NS vs D-AG 24 weeks).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

Distribution and ultrastructure of somatostatin-immunoreactive cells in the pancreas of Rana esculenta.

Apart from a description of the general organization of the endocrine pancreas, the present study is focussed on the distribution and ultrastructural morphology of somatostatin-immunoreactive cells in the pancreas of the frog Rana esculenta. For light-microscopic histochemistry, the peroxidase-antiperoxidase technique was used. For the ultrastructural investigation, we employed the immunogold method. The endocrine pancreas of R. esculenta is composed of numerous islet-like structures, which contain several small somatostatin-immunoreactive cells arranged in the form of clusters. Often, however, single somatostatin cells are randomly distributed among the acinar tissue of the pancreas. These individually arranged elements possess long processes which terminate on exocrine pancreatic cells. The ultrastructural features of somatostatin-immunoreactive cells speak in favor of their endocrine and paracrine functions.

Animals↗
PubMed1992

Effect of prolonged administration of insecticide (Cyhalothrin/Karate) on the blood and liver of rabbits.

A sublethal dose of Karate administered to rabbits produced a significant increase in the total erythrocyte count and packed cell volume after 15 days of administration, though no significant change was observed after 30 days. The transaminases (glutamate oxaloacetate transaminase, GOT; glutamate pyruvate transaminase, GPT) also increased after 15 days of treatment. The GPT activity increased 119% and 60% after 15 and 30 days, respectively. From amongst metabolites, glucose content increased 17% and 185%, while cholesterol decreased 40% and 66%, and bilirubin 84% and 61%, after 15 and 30 days, respectively. The hepatic AkP activity decreased 30%, while the GPT activity increased 44%. Other enzymes such as AcP, GOT and LDH remained unaffected. The concentration of other metabolites, except for FAA which increased 35%, remained unaffected. Histological changes were marked by atrophied hepatic cells and hypertrophied nuclei and nucleoli. A trend towards necrosis of hepatic cells was also observed. All these results indicate that Karate is moderately toxic to mammals.

Animals↗
PubMed1991

Cloning of xylanase gene of Streptomyces flavogriseus in Escherichia coli and bacteriophage lambda-induced lysis for the release of cloned enzyme.

The xylanase gene of Streptomyces flavogriseus was cloned in pUC8 plasmid and expressed in Escherichia coli lysogenic for lambda cI857. lambda-Induced lysis of E. coli at 42 degrees C allowed efficient release of cloned enzyme activity in extracellular environment. The xylanase gene was located in the 0.8-kb HindIII fragment and coded for 18,000 Mr xylanase.

Bacteriophage lambda↗
PubMed1991

Light- and electron-microscopic studies on isolated bovine islets of Langerhans.

While several recent studies have focussed on the critical assessment of yield, purity and function of isolated islets, fine-structural investigations of isolated islets have been the subject of only a few studies. After intraductal injection of collagenase solution, the distended bovine pancreata were processed in a continuous digestion-filtration device, after which the purification of the islet suspension was accomplished by density gradient centrifugation. Purified islets were then prepared for light- and transmission electron-microscopic analysis. In semithin sections, no evidence of either connective tissue or exocrine tissue surrounding isolated islets was found. Endocrine cells exhibiting cytoplasmic granules were packed in clusters varying in size. In ultrathin sections, A-cells containing numerous secretory granules were distinctive; their cytoplasm contained conspicuous formations of rough endoplasmatic reticulum and juxtanuclear Golgi complexes. In the B-cells, the Golgi complexes were also prominent; these elements, however, were poor in endoplasmic reticulum and displayed characteristic B-cell granules surrounded by a halo. A few ultrastructurally heterogeneous cells were scattered among the identified cellular elements.

Animals↗
PubMed1990

An improved silver staining technique as an alternative nuclear or combined nuclear nerve-fiber impregnation for comparative light-, secondary and backscattered electron scanning microscopy.

Slices of rat brain were stained by a new silver impregnation technique. This method takes into consideration the pH-dependent differences of silver stain affinity of nerve tissues and can be used alternatively as a stain for nuclei or as a method for combined demonstration of nuclei nerves fibers. The slices were studied at the light microscopical (LM) level and subsequently with a scanning electron microscope, using secondary (SSEM = classical SEM), and backscattered electron detectors (BSEM). This new silver staining technique offers the opportunity of comparative studies with regard to different information acquired with LM, SSEM and BSEM. The described method allows to distinguish between nervous and glial tissue without necessarily damaging the glial tissue surrounding the nerve fibers. Specifically, scanning electron microscopy with backscattered electron detector of in situ preparations provides a higher contrast of stained and unstained tissue and increased depth of focus as compared to secondary electron detectors.

Animals↗
PubMed1988

Effects of six months' feeding of cypermethrin on the blood and liver of albino rats.

A cypermethrin-mixed diet was fed uninterrupted to male albino rats for six months to evaluate toxicity in nontarget organisms. The rats consumed cypermethrin at a dose of 420 mg active ingredient (AI) per kilogram body weight per day. At the end of the stipulated period, the blood and liver were analyzed for insecticidal toxicity. The hemoglobin content and white blood cell (WBC) count remained unaltered, while the red blood cell (RBC) count and packed-cell volume (PCV) decreased significantly. The blood serum lactate dehydrogenase (LDH), isocitrate dehydrogenase (ICDH), and amylase activities were elevated 61%, 30%, and 46%, respectively, after six months of insecticide feeding, suggesting liver and possibly pancreas malfunction. The glutamate oxaloacetate transaminase (GOT) and creatine phosphokinase (CPK) activities, on the other hand, decreased 37% and 40%, respectively. The blood serum protein and free amino acids (FAA) content increased 12% and 31%, respectively, while cholesterol content decreased 49%. Consequent to cypermethrin administration the hepatic GOT, LDH, and ICDH activities increased 250%, 20%, and 30%, respectively. The soluble proteins, FAA, and glucose contents exhibited significant increases of 28%, 61%, and 71%, respectively. Histological changes were marked by hypertrophied hepatic cells and nuclei.

Amino Acids↗
PubMed1988

[Experimental and clinical results with the ileum pouch as a continence-preserving replacement bladder].

Clinical use of the ileum-pouch for bladder reconstruction without stoma and direct anastomosis to the urethra is mandatorily based upon the three following conditions: sufficient capacity, low pressure values and protection of reflux in the neobladder. In an experimental study, we constructed a U-pouch with anastomosis to the urethra and implantation of both ureters into a cranial ileum horn. Already six weeks postoperatively an optimal capacity and real low pressure conditions of the neobladder have been achieved. Without any ileoileal invagination as antirefluxive procedure simple ureter-nippling provides a highly efficient protection against renal reflux in the so constructed neobladder. Our first clinical results do confirm our experimental data, demonstrating no reflux and almost total continence.

Animals↗
PubMed1987

Microvasculature of the pineal organ of the rainbow trout (Salmo gairdneri).

The angioarchitecture of the pineal organ of the rainbow trout (Salmo gairdneri) was investigated by means of the corrosion-cast preparation method and scanning electron microscopy. Two main arteries (aa. epiphyseales) supply the pineal parenchyma. They emerge from the aa. cerebri anteriores and run in the fissure between the prosencephalon and the mesencephalon. After entering the pineal stalk, the aa. epiphyseales branch off into several arterioles, most of which extend to the pineal end-vesicle where they give rise to a lobular, bilaterally symmetric capillary network. Capillaries establishing the main portion of the pineal vessels appear widened in comparison to those supplying other portions of the brain and resemble capillaries in other endocrine organs. In Salmo gairdneri, no specialized system of portal vessels appears to exist between the pineal organ and other portions of the brain.

Animals↗
PubMed1984

Evaluation of liver function after thioacetamide treatment of partially hepatectomized rabbits.

A group of male rabbits was partially hepatectomized, while another group was administered intraperitoneally with aqueous thioacetamide (TAA) solution (2 mg/kg body weight/alternate day) after partial hepatectomy (PH). The blood samples of animals of both groups were collected on day 10, 15, 20, 30, 60 and 90 following PH and used for various haematological and biochemical analyses. The haemoglobin content decreased significantly within 10 days of PH and gained significant increase 3 months after. An abrupt increase was, however, recorded after TAA treatment. All the enzymatic activities remained unchanged except for that of lactate dehydrogenase (LDH), which was elevated 87% during the first 10 days of PH. The serum glutamate pyruvate transaminase (SGPT) activity was raised 2.8 times. It was only two months after the operation that the alkaline phosphatase (AP) and LDH activities showed signs of inhibition. The only enzyme affected by TAA treatment after the PH was AP activity, which was inhibited drastically within 15 days after operation. It was concluded that, except for the AP activity and bilirubin and urea content, that essentially decreased in the presence of TAA during the first 15-20 days of experimental period, all the other haematological and biochemical parameters got normalized more quickly in the presence of TAA.

Acetamides↗
PubMed1982

Bile acids. LXVII. The major bile acids of Varanus monitor.

The major bile acids of gall bladder bile of Varanus monitor have been separated by thin-layer chromatography and shown to be derivatives of taurine. After alkaline hydrolysis, the free acids were separated by thin-layer and partition chromatography. Identification or characterization of the free acids was facilitated by gas-liquid chromatography and gas-liquid chromatography-mass spectometry of the methyl esters or methyl ester-trimethylsilyl ethers. About 13% of the total bile acids was represented by the C24 acids cholic, deoxycholic, allocholic, chenodeoxycholic, and 12-oxo-3 alpha-hydroxy-5 beta-cholanic acids, of which cholic acid constituted about 50%. The remainder of the bile acids consisted of eight C27 acids of which varanic acid was the major constituent; an isomer of varanic acid and 3 alpha, 7 alpha, 12 alpha-trihydroxy-5 beta-cholestanoic acid were also identified. By chromatographic behavior and mass spectral fragmentation, the structures of four C27 acids with unsaturated side chains were elucidated as follows: 3 alpha, 7 alpha-dihydroxy-5 beta-cholest-23-enoic, 3 alpha, 7 alpha-dihydroxy-5 beta-cholest-24-enoic, 3 alpha, 7 alpha, 12 alpha-trihydroxy-5 beta-cholest-23-enoic, and 3 alpha, 7 alpha, 12 alpha-trihydroxy-5 beta-cholest-24-enoic acids. Similarly, the structure of the 12-deoxy analog of varanic acid, 3 alpha, 7 alpha, 24 xi-trihydroxy-5 beta-cholestanoic acid, was suggested for the component that constituted 7% of the total.

Animals↗
PubMed1980

Immunofluorescent staining experiments in parathyroid glands.

An antiserum against bovine parathyroid hormones was raised and applied for demonstration of parathormone-containing cells. Parathyroid glands of frog, fowl, dog, cattle and rat were used with different tissue preparation procedures. The best results were obtained in rats stimulated by previous intraperitoneal injection of sodium glycerophosphate. Bovine parathyroids were also positive after glutaraldehyde fixation and paraffin embedding.

Animals↗
PubMed1978

Histological and ultrastructural studies on the ringbands in human extraocular muscles.

Ringbands are a typical finding in the extraocular muscles of individuals of twenty years and older. The number of these structures increases distinctly after the 60th year of life. In optimally fixed muscles the ringbands are separated from the sarcolemma by a space containing the so-called sarcoplasmic masses. These masses were composed of vaculated mitochondria, dilated tubules of the sarcoplasmic system and, in some fibers, of fragments of myofibrils. Structures from which a neoformation of myofibrils as the origin of the ringbands could be concluded (as proposed by Jonecko, 1967), were never observed in this hypolemmal area. In contrast, the formation of the ringbands seems to be correlated to the ultrastructural alterations of the myofilaments and the looser arrangement of the myofibrils which can first be observed in extraocular muscles of 10-year-old patients and increasingly in older patients (Mühlendyck, 1977). These alterations lead to continous and repeated changes in the orientation of the myofibrils during the extension and contraction processes of the muscle fiber. Thus, the myofibrils undergo a constant mechanical stress which they cannot resist indefinetly, leading to disruption of some of the fibrils. The disrupted free end contracts, deviates almost at a right angle from its former course and, while the sarcolemma forms thread-like folds during the contraction of the muscle fiber, it is coiled around the longitudinal undisrupted fibrillar core. This leads to a disfunction of the muscle fiber and aids in explaining the steady decrease of the excursion of the eye after about 30 years of age.

Adult↗