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Biomedical subjects

Y Ahmed

Publications and source records attributed to Y Ahmed.

30 records · Page 2Linked to original sources
PubMed1991

Changes in platelet function in pregnancies complicated by fetal growth retardation.

Platelet function was investigated in three patients with severely decreased fetal growth rates detected by ultrasound scanning. Only one patient had hypertension, which was mild and developed after decreased fetal growth and altered platelet responses had been detected. Much higher concentrations of platelet-activating factor (PAF) (20-500 nM) were required to stimulate maximal platelet aggregation in all three patients compared with the concentrations of PAF (5-10 nM) required in control pregnancies of similar gestational age. In a fourth patient, platelet desensitisation was observed 5 weeks before the detection of decreased fetal growth. These results are similar to those observed in women with hypertensive disorders of pregnancy, and indicate that there may be a similar change in platelet function in gestational hypertension and in fetal growth retardation, although the clinical manifestations are different.

Blood Platelets↗
PubMed1991

Detection of platelet desensitization in pregnancy-induced hypertension is dependent on the agonist used.

The aggregation of platelets from women with pregnancy-induced hypertension (P.I.H.), or with normal pregnancies, in response to arachidonic acid, ADP, collagen or platelet activating factor (PAF) was examined. No differences in platelet aggregation between the normotensive and hypertensive women were detected when arachidonic acid or collagen were used to stimulate in vitro platelet aggregation. Higher concentrations of ADP and PAF were required to aggregate platelets from women with P.I.H. compared with platelets from normotensive controls. Platelets from women with normotensive pregnancies (n = 80) aggregated maximally in response to 20 nM PAF without exception. Reversible aggregation by platelets from women with P.I.H. (n = 25) was observed at the same concentration of PAF; again, this was found in all subjects tested. These results indicate that PAF at a concentration of 20 nM can clearly demonstrate differences in aggregation of platelets from women with normotensive pregnancy and women with P.I.H.

Adenosine Diphosphate↗
PubMed1988

Villin sequence and peptide map identify six homologous domains.

Site-specific proteases and antisera to the amino terminus of villin have been used to show that villin is organized into seven protease-resistant domains. Six are contained in the amino-terminal Mr 87,000 villin core, a Ca2+-regulated actin-severing fragment, whereas the carboxyl-terminal domain includes the villin "headpiece," a fragment involved in bundling of actin filaments. Ca2+ inhibits proteolytic cleavage between domains in the amino-terminal half of villin. The protein sequence of villin deduced from a single cDNA clone contains a conserved sequence that is repeated six times and is found in each domain of the villin core. The conserved repeats are found in other actin-severing proteins but not in the villin headpiece. Our results suggest that actin-severing proteins are organized around a common Mr 14,000-17,000 domain.

Amino Acid Sequence↗
PubMed1984

Multiple endocrine neoplasia type II: the role of gastrointestinal humoral factors in calcitonin release following alcohol and pentagastrin stimulation.

Familial medullary carcinoma of thyroid (MCT) can be diagnosed early by measuring stimulated plasma calcitonin following provocation with 50 ml of oral whisky, or 0.5 microgram kg-1 i.v. pentagastrin. The calcitonin release, however, can be variable following both stimuli. To determine whether a humoral mechanism might be involved in mediating this calcitonin release, nine gut peptides, histamine, alcohol, calcium, and calcitonin, were measured in the plasma of eight patients whose family was affected by multiple endocrine neoplasia Type II syndrome. Pentagastrin produced significant rises in plasma calcitonin, histamine and pancreatic polypeptide. Whisky produced a variable rise in plasma alcohol, but significant rises in plasma calcitonin, histamine and pancreatic polypeptide as well as insulin (P less than 0.05). This study suggests that histamine may be the mediator of calcitonin release following provocation by either pentagastrin or alcohol. Histamine infusion requires evaluation as a screening test for MCT in MEN II syndrome.

Adrenal Gland Neoplasms↗
PubMed1979

The effect of fetal head compression and fetal acidaemia during labour on human fetal cerebral function as measured by the fetal electroencephalogram.

We investigated the effect of head compression and acidaemia during labour in 25 African primigravidae. Evidence that head compression had occurred during labour was confirmed by both clinical and radiological means at the end of a trial of labour. No significant difference could be demonstrated in the quantity of fetal electroencephalogram (EEG) abnormality that occurred in the groups with marked head compression as compared to the groups without marked head compression. Deterioration in the fetal EEG to a flat record known as electrocerebral silence (ECS) was associated with the development of acidaemia. As fetal heart rate (FHR) decelerations appeared the percentage of ECS in the fetal EEG record increased significantly (P less than 0.05), and likewise, as fetal acidaemia developed a highly significant increase in ECS in the fetal EEG was demonstrated (P less than 0.001). We concluded that in the management of trial of labour there was no significant deleterious change in the fetal EEG as a result of head compression, unless fetal acidaemia supervened. However, in the majority of these cases a significant increase in ECS to more than 20 per cent occurred in association with only moderate acidaemia (pH 7.25 to 7.30).

Acidosis↗
PubMedDate not supplied

Routine antenatal syphilis screening--a case against.

To highlight the deficiencies associated with the routine antenatal syphilis screening as it is done now in the University College Hospital, Ibadan, and determine the cost effectiveness or otherwise of syphilis screening using as parameters the specificity of the method of screening as well as the gravity of the disease. The results of VDRL tests performed on pregnant women attending the antenatal clinic of the University College Hospital, Ibadan, in a 10-year period, January 1988 to December 1997 were analysed for seropositivity as well as congenital syphilis. The case notes of 110 sero-reactive patients were retrieved and analysed for pregnancy outcome. The prevalence rate of seropositive patients was 1.1%. Only 3 of the seropositive had repeated tests and were treated empirically with high doses of penicillin. There was no case of congenital syphilis. This study has shown that the syphilis screening as it is done now is not cost-effective. If VDRL test is to be continued, efforts must be made to reintroduce TPHA-test, which is more specific-specificity; it wastes a lot of time and money of the patients. Hence it is not cost effective. If VDRL test is to be continued efforts must be made to reintroduce TPHA-test, which is more specific.

Cost-Benefit Analysis↗