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Biomedical subjects

S Amer

Publications and source records attributed to S Amer.

17 recordsLinked to original sources
PubMed2005

An integrated platform for bio-analysis and drug delivery.

The advances in the microelectronics fabrication allow the strong appearance of micro-electro-mechanical systems known as MEMS. MEMS enable the fabrication of smaller devices that are manufactured using standard micro-fabrication techniques similar to the ones that are used to create computer silicon chips. Several MEMS devices including micro-reservoirs, micro-pumps, cantilevers, rotors, channels, valves, sensors, and other structures have been designed, fabricated and tested from using materials that have been demonstrated to be biocompatible. This paper reviews the status of Micro-electronic and MEMS systems that can be used for adaptive drug administration. It presents different components and describes a possible implementation. Finally it presents a prototype that is termed ipill which stands intelligent pill.

Drug Delivery Systems↗
PubMed2001

Salivary glucose concentrations in patients with diabetes mellitus--a minimally invasive technique for monitoring blood glucose levels.

Salivary and blood glucose concentrations were determined in non-diabetic healthy individuals and patients with diabetes mellitus (type II). Glycosylated haemoglobin A1c was also determined in some of the patients (n = 25) and a significant correlation (r = 0.82) was found between HbAlc and serum glucose concentrations in these patients, indicating that these patients had average elevated blood glucose concentration over an extended time period. Glucose was only found in the saliva of patients with diabetes mellitus (n = 135), while the salivary samples of age matched non-diabetic subjects (n = 25) did not show the presence of glucose. A significant correlation (r = 0.78) was found between salivary and blood concentrations in the diabetics. This finding suggests that saliva can be used reliably for reflecting and monitoring the blood glucose concentration in the patients of diabetes mellitus.

Journal Article↗
PubMed2000

Evidence for an intrarenal renin-angiotensin system in the rainbow trout, Oncorhynchus mykiss.

Physiological and molecular approaches were used to investigate the existence of an intrarenal renin-angiotensin system (RAS) in rainbow trout. Inhibition of angiotensin-converting enzyme by captopril (5 x 10(-4 )M) rapidly decreased vascular resistance of the trunk of the trout, perfused at 19 mmHg, resulting in an increased perfusate flow rate and a decreased intrarenal dorsal aortic pressure. A profound diuresis occurred in the in situ perfused kidney and reflected both increased glomerular filtration rates and decreased water reabsorption (osmolyte reabsorption was unchanged). Renal and vascular parameters recovered once captopril treatment was stopped. Diuretic and vascular effects of captopril on the in situ trout kidney concur with an inhibition of known vasoconstrictor and antidiuretic actions of angiotensin II. However, at a higher perfusion pressure (28 mmHg), captopril had no effect on intrarenal aortic pressure or perfusate and urine flow rates, suggesting that the trout intrarenal RAS is activated by low perfusion pressures/flows. Existence of the renal RAS in trout was further supported by evidence for angiotensinogen gene expression in kidney as well as liver.

Angiotensin II↗
PubMed1999

The hypolipidaemic effect of gum tragacanth in diet induced hyperlipidaemia in rats.

Previous research indicated that fiber in the diet of men lowers plasma lipid and LDL cholesterol concentration. To further study the lipid lowering effect of fibre, we conducted an animal study using rats with diet induced hyperlipidaemia. Rats were randomly assigned to one of the three experimental diets. Two of the diets contained cholesterol and choice acid to induce hyperlipidaemia, the fiber source in the hyperlipidaemic diet was gum tragacanth (5%). The rats consumed one of the three diets ad libitum for 4 weeks before they were killed. Plasma LDL cholesterol and total cholesterol concentrations were significantly higher in the hyperlipidaemic group than in the non hyperlipidaemic control group. A marked improvement in the plasma LDL cholesterol and total cholesterol concentration was observed in the rats that were fed hyperlipidaemic diet containing grum tragacanth. No significant difference in the plasma triglyceride concentration was detected in the three groups. Plasma HDL concentration was significantly higher in the non-hyperlipidaemic group than in the hyperlipidaemic group than. Addition of gum tragacanth to the hyperlipidaemic diet significantly improved the plasma HDL concentration in the hyperlipidaemic rats. These results suggest that fiber from gum tragacanth lowers plasma cholesterol and LDL in hyperlipidaemia. Gum tragacanth could be useful adjunct to the dietary management of hyperlipidaemia.

Journal Article↗
PubMed1995

Glomerular actions of arginine vasotocin in the in situ perfused trout kidney.

Recent measurements of plasma arginine vasotocin (AVT) in teleost fish suggest circulating concentrations of 10(-10)-10(-12)M. Previous studies of the renal actions of AVT in vivo suggest both diuretic and antidiuretic effects, but at unknown circulating concentrations. We have investigated the renal actions of 10(-9) and 10(-11) M AVT in vitro using an in situ perfused kidney preparation of rainbow trout (oncorhynchus mykiss). AVT increased vascular resistance (56%), reduced perfusate flow (P < 0.001), and increased interrenal aortic pressure (P < 0.001). AVT resulted in dose-dependent decreases in urine flow rates, glomerular filtration rates, and tubular transport maxima for glucose. AVT at 10(-11) M reduced relative free water clearances (P < 0.01), but urine/plasma inulin ratios were unchanged, whereas 10(-9)M AVT reduced urine/plasma inulin ratios (P < 0.01) and increased relative free water clearances (P < 0.05). The filtering population of glomeruli was reduced by both 10(-11) and 10(-9)M AVT to approximately one-third of the glomeruli, and a similar population of arterially perfused but nonfiltering glomeruli emerged. These results demonstrate that physiological concentrations of AVT have potent glomerular antidiuretic action in the trout, reducing the number of functional glomeruli, and imply reduced individual nephron filtration rates.

Animals↗
PubMed1992

Enzyme-linked immunosorbent assay for diagnosis of acute sporadic hepatitis E in Egyptian children.

Hepatitis E virus (HEV) is thought to be a cause of enterically transmitted non-A, non-B (ET-NANB) hepatitis. Waterborne epidemics have been recorded in many developing countries, mainly affecting young-to-middle-aged adults; sporadic infection and overt illness in children are rare. However, a convenient and sensitive diagnostic test for HEV infection is not yet available. We now report the use of a solid-phase enzyme-linked immunoassay (ELISA) that detects IgM and IgG antibody to HEV. In a prospective study of endemic acute hepatitis during 1986 in rural Benha, Egypt, 15 (42%) of 36 children with NANB hepatitis (from whom convalescent-phase sera were available every 3 months to 9 or 12 months) were positive for anti-HEV-IgG by ELISA. Of 20 sera from healthy Benha children (controls), 5 (25%) were also positive for anti-HEV-IgG. When evaluated for anti-HEV-IgM, 6 of the 15 IgG-positive children, but none of the controls, were IgM positive and were thus regarded as having confirmed acute HEV infections. These 6 cases together with 2 presumptive cases (IgM negative, IgG seroconversion from positive to negative) presented sporadically over 9 months. This ELISA is a convenient method for the diagnosis of HEV infection; we have shown that the disease is present in Egypt, that it can occur endemically as sporadic cases, and that children do have overt infection.

Adolescent↗
PubMed1989

The molluscicidal properties of Ambrosia maritima L. (Compositae). 4. Temporal and spatial distribution of Biomphalaria alexandrina in Egyptian village irrigation systems with reference to schistosomiasis transmission control.

Data on the temporal and spatial distribution of Biomphalaria alexandrina were collected throughout one year in two village irrigation systems near Alexandria, Egypt. Snails bearing Schistosoma mansoni cercariae were found from May to December but about 80% of annual transmission potential was confined from June to August. Although snail infection rates were generally 0-2%, higher rates were recorded and tended to be associated with smaller number snail collections. Infected snails were found in most canal and drain types and were judged to be present across most of the irrigated area of each village. In view of the dispersed nature of both infected snails and human-water contact in the area, it is suggested that schistosomiasis transmission is more widespread than focal. Effective transmission control using molluscicides should therefore require application to all village irrigation water-courses. The difficulties these various findings might impose on the use of commercial molluscicides are discussed and some possible advantages of the alternative plant molluscicide, Ambrosia maritima are noted.

Animals↗
PubMed1987

The molluscicidal properties of Ambrosia maritima L. (Compositae). 3. A comparative field trial using dry and freshly-harvested plant material.

A comparative trial of freshly-harvested and dry forms of the plant molluscicide, Ambrosia maritima is described. The plant was grown near Alexandria, Egypt and gave a weight ratio of 4:1 for fresh: dry, mature plants. Applications of plant material were made to irrigation watercourses at dosage levels of 560 mg . l-1 fresh and 70 and 140 mg . l-1 dry in May and 280 mg . l-1 fresh and 70 mg . l-1 dry in June. Snail numbers were reduced to low levels after two weeks in all treatments. Statistically significant differences could not be detected between the molluscicidal effects of fresh and dry material or their use in May and June. The cultivated plant has a similar order of activity to that collected from the wild. The snail number reduction was maintained to the end of the year in all treatments. This confirms an earlier finding that a correctly-timed, single application of the plant is capable of controlling snails throughout the entire schistosomiasis transmission season in Lower Egypt.

Animals↗
PubMed1986

Effect of subdermal levonorgestrel contraceptive implants on vaginal candidiasis.

A total of 150 women in 3 equal groups, each using a different contraceptive method (group I used Norplant, group II used the IUD and group III used combined OC pills) were investigated for the presence of vaginal candidiasis before and at various time intervals (3, 6 and 12 months) after starting to use the particular contraceptive method. The incidence of vaginal Candida albicans infection increased significantly among pill and IUD users, but with a much lower intensity among the latter cases. In Norplant users the increase was slight and insignificant. The explanation of these findings within the context of changes in local vaginal milieu is discussed.

Adult↗
PubMed1976

Mononeuritis multiplex in a patient with macroglobulinaemia.

A case is described of a 73 year old male with Waldenström's macroglobulinaemia and hyperviscosity in association with neurological abnormalities, the Bing-Neel syndrome. The relationship of the clinical features to changes in serum viscosity and the response to therapy with plasmapheresis and chlorambucil are discussed.

Aged↗