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Biomedical subjects

S Ansari

Publications and source records attributed to S Ansari.

At least 37 records · Page 2Linked to original sources
PubMed1998

Kinematic posterior cruciate ligament-retaining total knee replacements. A 10-year survivorship study of 445 arthroplasties.

Survival was tested in 445 primary Kinematic knee replacements performed between January 1981 and December 1990. Three criteria were applied to indicate failure: 1) revision or recommended revision, 2) presence of moderate to severe pain or revision, and 3) lost to follow-up or revision. Using these three criteria, the survival rate at 10 years was 96%, 78%, and 69%, respectively. At last follow-up examination, 84% of knees had good or excellent Bristol knee scores with mean range of motion 100 degrees. Overall, 11 knees (2.5%) have been revised and 27 cases (6%) were graded as failures due to presence of moderate to severe pain at the time of the last evaluation. These results indicate that the posterior cruciate ligament-retaining Kinematic prosthesis provides satisfactory function and survival up to 10 years.

Arthritis, Rheumatoid↗
PubMed1997

Phase II clinical trial of a vas deferens injectable contraceptive for the male.

Following up on an earlier clinical trial demonstrating the safety of an intra-vas deferens injection of a contraceptive drug named Risug, comprised of styrene maleic anhydride (SMA) in a solvent vehicle of dimethylsulphoxide (DMSO), a study to assess the contraceptive effectiveness of a specific dose (60 mg) of SMA bilaterally was planned and implemented. Male subjects and their wives with normal reproductive profiles were the volunteer subjects. The wives were not using any contraceptives. The results reconfirm the safety and show that for a period of at least 1 year, the treatment leads to azoospermia in the male and gives pregnancy protection.

Adult↗
PubMed1997

Incidence of fatal pulmonary embolism after 1,390 knee arthroplasties without routine prophylactic anticoagulation, except in high-risk cases.

A consecutive series of 1,390 primary total knee arthroplasty (TKA) procedures (1,201 patients, 1,600 arthroplasties) performed between January 1980 and July 1994 were reviewed to establish the incidence of death from pulmonary embolism (PE). Nine hundred twenty-three bi- or tricompartment TKAs and 467 unicompartment TKAs were performed as one-stage procedures. Chemical thromboprophylaxis was used only in high-risk cases in which there was a history of previous thromboembolism or obesity. There were no deaths from PE after unicompartment arthroplasty procedures. Autopsy confirmed PE as the cause of death in 2 patients following bi- and tricompartment TKAs (0.22%; 95% confidence interval [CI], 0.03-0.8%). The incidence was higher for one-stage bilateral TKA as 1 of the autopsy-confirmed deaths occurred in this group 0.7% (95% CI, 0.02-3.78%). Two other deaths were certified without postmortem examination (pneumonia and myocardial infarction in each case). As PE could not be ruled out as the cause of death in the latter 2 cases, these were considered as possible PE deaths to provide the maximum possible death rate that could result. Thus, the maximum possible incidence of fatal PE after TKA without routine use of chemical anticoagulation was 0.4% (95% CI 0.1-1.1%). It is concluded that the risk of fatal PE after unilateral TKA and unicompartment knee arthroplasty is low. The risk of clinical, nonfatal thromboembolic events, which might themselves warrant prophylaxis, was not quantified in this article.

Adult↗
PubMed1997

St. Georg sledge for medial compartment knee replacement. 461 arthroplasties followed for 4 (1-17) years.

We evaluated the long-term outcome of 461 medial compartment knee arthroplasties operated at one orthopedic center from 1974 to 1993 through survivorship analysis. Prospective assessment was based on clinical examinations using a modified Bristol knee-scoring system and complete radiographical knee survey. 92% had good or excellent results on objective scoring, and range of motion averaged 112 degrees. 3 criteria were applied to indicate failure: 1) revision or recommended revision, 2) severe-to-moderate pain or revision, 3) lost to follow-up. 20 arthroplasties were revised or recommended to be revised at mean 5.5 years. The incidence of failure due to progression of arthrosis in the unreplaced compartment was low (< 2%). Loosening or wear occurred in 6 cases (1.5%), 2 of which developed fracture of implant. With revisions only as end-point to failure, the survival was 87% at 10 years (95% CI 81%-93%, effective number at risk = 133). In addition to revisions, 19 knees were considered to have failed, as moderate-to-severe pain was noted at follow-up and the survival was reduced to 74% at 10 years with pain or revision as endpoint (95% CI 65%-82%, effective number at risk = 105). We conclude that unicompartmental knee arthroplasty gives long-term pain relief in elderly patients with medial compartment arthrosis.

Aged↗
PubMed1993

Effect of miconazole on the structure and function of plasma membrane of Candida albicans.

The primary mode of action of azoles is the inhibition of cytochrome P-450 dependent 14 alpha-demethylase, a key enzyme in ergosterol biosynthesis in fungi. Our results demonstrated that Candida albicans cells grown in the presence of 10 micrograms ml-1 of miconazole (miconazole-grown), do not possess ergosterol in their plasma membranes and this ergosterol depletion leads to a drastic change in membrane fluidity as shown by fluorescence polarization measurements and unsaturation index. There was an increase in membrane order in miconazole-grown cells and a reduced rate of uptake of amino acids. We also checked for membrane permeability changes in normal mid-log phase cells (normal-grown) in short incubations (10 min) with 10 micrograms ml-1 miconazole (miconazole-incubated). Interestingly, the amino acid uptake rates except that of Gly were not affected significantly in these cells. The results suggest that in the miconazole-incubated cells, the drug is not able to alter the level of ergosterol or inhibit ergosterol biosynthesis during 10 min incubation and therefore the interaction of the drug neither leads to significant disorganization of membrane components, nor affects permease activity, whereas in the miconazole-grown cells there is ergosterol depletion leading to accumulation of biosynthetic intermediates, resulting in membrane rearrangement thereby causing a major fluidity change. This fluidity change may explain the drastic reduction of amino acid transport in miconazole-grown cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acids↗
PubMed1993

Phase I clinical trial of an injectable contraceptive for the male.

Earlier studies on the rat and the monkey had demonstrated that an injection of styrene maleic anhydride (SMA) in a solvent vehicle of dimethyl sulphoxide (DMSO) into the lumen of the vas deferens is toxicologically safe and has contraceptive action. Phase I clinical trial was therefore undertaken on 38 male volunteers giving varying doses of SMA, ranging between 5 mg and 140 mg, into each vas deferens. A dose of 70 mg is the predicted therapeutic dose based on animal data. That the compound is within the vas deferens lumen during the period of the safety assessment is inferred from the effect on the spermatozoa count in ejaculates which reach azoospermic levels in the higher dose ranges. The treatment is well tolerated with only minimal side effects in a few cases and no long-term adverse effects.

Adult↗
PubMed1992

Teratoid Wilms' tumour: a report of two cases.

We report two cases of Wilms' tumour in which the degree of heterologous differentiation was sufficient to warrant the diagnosis of teratoid Wilms' tumour. The first description of neural elements in this Wilms' variant and the first cytogenetic analysis of teratoid Wilms' tumour are presented.

Child, Preschool↗
PubMed1992

Transport of acidic amino acids in Candida albicans.

In Candida albicans ATCC 10261, two kinetically different amino acid transport systems with a high (S1) and a low (S2) affinity for aspartic acid (asp) and glutamic acid (glu) were identified. The S1 for the two acidic amino acids was characterized by low Kt values while Kt values of S2 were 30 to 40 times higher. Based on competitive studies of both systems, S1 was found to be specific and common to both asp and glu while S2 was relatively less specific. The S1 and S2 systems were also different in their sensitivity to respiratory inhibitors, mercurials and a K+ channel blocker. Both systems, however, showed maximum transport rates during the mid-exponential growth phase.

Aspartic Acid↗
PubMed1991

Vanadate-resistant mutants of Candida albicans show alterations in phosphate uptake.

Phosphate uptake studies in different strains of the dimorphic pathogenic yeast Candida albicans were undertaken to show that this yeast actively transported phosphate with an apparent Km in the range of 90-170 microM. The uptake was pH dependent and derepressible under phosphate starvation. Vanadate-resistant (van) mutants of C. albicans showed a 20-70% reduction in the rate of phosphate uptake in high phosphate medium and was associated with an increased Km and reduced Vmax. The magnitude of derepression under phosphate starvation was different between van mutants. These results demonstrate that van mutants may have developed resistance by modifying the rate of entry of vanadate.

Biological Transport↗
PubMed1991

Isolation, purification and kinetic characterization of plasma membrane H(+)-ATPase of Candida albicans.

The plasma membrane ATPase of Candida albicans was solubilized by Tween 40 and purified to homogeneity on glycerol step gradient. The purified protein appeared as a single band of 100 +/- 4 KDa, represented greater than 98% of the total pure protein on densitometer scan. The purified PM-ATPase which was very specific to MgATP, had Km of about 0.77 mM and a sharp pH optimum at 6.6. Orthovanadate was able to inhibit the enzyme in a non-competitive manner, however, at higher concentrations the nature of inhibition changed to uncompetitive type. Based on molecular size, immuno cross-reactivity and sensitivity to different inhibitors, PM-ATPase of C. albicans appears to be similar to other ion pumps.

Adenosine Triphosphate↗
PubMed1990

Time-controlled injectable occlusion of the vas deferens.

An injectable method of obtaining vas deferens occlusion is presented. The agent used is styrene maleic anhydride (SMA) with dimethyl sulphoxide as the solvent. The special feature of the approach is that after a period of time, spermatozoa passage is spontaneously reestablished. By varying the dose of SMA administered, the interval between injection and restoration of spermatozoa flow can be regulated from as short a period as about 3 months to more than five years.

Animals↗
PubMed1985

Contraception in male monkeys by intra-vas deferens injection of a pH lowering polymer.

A new male method of contraception by injecting a polymer, styrene-maleic anhydride (SMA), into the lumen of the vas deferens has been studied on rhesus monkeys. The polymer has the dual feature that it can occlude the vas deferens lumen and also it can inhibit the fertilising ability of spermatozoa by virtue of the pH lowering effect. Matings with females were carried out when the lumen was completely occluded giving azoospermia as well as with partial block and spermatozoa present in the semen. All matings were infertile. Data up to one year is presented. All indications are that the contraceptive effect will last for a considerably long period.

Animals↗
PubMed1982

Alterations in intestinal function in response to thyroxine and cortisone administration in undernourished rats.

Imposition of undernutrition during the suckling period considerably enhanced the intestinal uptake of D-glucose and glycine compared to a control group. Brush border sucrase, and alkaline phosphatase activities were drastically reduced while lactase and leucine amino peptidase levels were significantly elevated at weaning in nutritionally deprived pups as compared to control animals. Cortisone administration to undernourished rats depressed the uptake of D-glucose but stimulated that of glycine. Thyroxine treatment to undernourished animals reduced the uptake of glucose but had no effect on glycine absorption. Brush border sucrase and alkaline phosphatase activities were stimulated in cortisone- or thyroxine-injected undernourished rats but lactase activity was depressed under these conditions. Leucine aminopeptidase activity remained unaffected in cortisone- or thyroxine-administered undernourished pups.

Animal Nutritional Physiological Phenomena↗
PubMed1981

Effect of folate deficiency on the digestive and absorptive functions of intestinal epithelium in rats.

The effect of folate deficiency, induced by a folate deficient diet, on the digestive and absorptive functions of the intestinal epithelium in rats has been investigated. The intestinal uptake of D-glucose and L-alanine and the brush border sucrase, lactase and alkaline phosphatase activities were considerably depressed in folate deficient animals compared to the control group. Kinetic studies with brush border sucrase in control and deficient animals revealed that reduced levels of the enzyme in folate deficiency are due to a reduced number of enzyme molecules. There was no change in activity of lactate-dehydrogenase in enterocytes of folate deficient rats.

Alanine↗