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Biomedical subjects

E Ahmed

Publications and source records attributed to E Ahmed.

At least 37 records · Page 2Linked to original sources
PubMed1999

Anti-cardiolipin antibodies and circulating immune complexes in type 1 diabetes mellitus: increased prevalence and relation to vascular complications.

Anti-cardiolipin antibodies, oxidatively modified low-density lipoproteins (oxLDL) and circulating immune complexes are humoral factors that have been linked to vascular damage. To analyse their possible role in the vascular complications in type 1 diabetes mellitus, we investigated patients with and without vascular complications (retinopathy, nephropathy, polyneuropathy, foot ulcers). The patients were matched for age, sex and duration of diabetes. The patients were also compared with 102 healthy individuals. Anti-cardiolipin antibodies of IgG and IgA type were more common in patients compared with healthy individuals. There was no difference between patients with and without vascular complications. There was no increased prevalence of IgM anti-cardiolipin antibodies, but the levels of these antibodies were higher in patients with vascular complications compared with patients without complications and controls. Eighty-three percent of patients had circulating immune complexes in comparison with 5% of healthy individuals. Such complexes were more common in patients with complications. Both the prevalence and the levels of immune complexes were higher in patients with null alleles of complement factor C4. Patients with vascular complications had higher prevalence of C4A than of C4B null alleles. Anti-cardiolipin antibodies were present in higher relative concentrations in immune complex form than in serum in all six patients analysed. There was no increased prevalence of antibodies against oxidatively modified LDL in the patients. The higher prevalence and levels of anti-cardiolipin antibodies and circulating immune complexes in patients with vascular complications suggests that these humoral factors might be involved in the vascular complications of type 1 diabetes mellitus.

Adult↗
PubMed1999

Adult granulosa cell tumor of the ovary with foci of hepatic cell differentiation: a report of four cases and comparison with two cases of granulosa cell tumor with Leydig cells.

We report four ovarian granulosa cell tumors of the adult type containing small foci of hepatic cell differentiation. The patients ranged in age from 35 to 54 years and had unilateral adnexal masses. The smallest tumor was 4.0 cm in diameter and the largest, 11.0 cm in diameter. Three tumors were solid and cystic, and one was cystic. Microscopic examination showed typical patterns of adult granulosa cell tumor, with the additional finding of scattered islands of large cells with abundant eosinophilic, slightly granular cytoplasm and central round nuclei containing single prominent nucleoli. Bile pigment was detected in canaliculi between some of the large cells in three tumors. The hepatic cells were positive immunohistochemically for cytokeratin (CAM 5.2) and epithelial membrane antigen in two cases and alpha-fetoprotein in one of two cases. Carcinoembryonic antigen was stained in a canalicular pattern in two cases. Staining for vimentin and alpha-inhibin was negative. Liver cells in granulosa cell tumors must be differentiated from Leydig cells, which are found very rarely in granulosa cell tumors, and luteinized stromal and granulosa cells, which are present more commonly in these tumors; all three of the latter cell types are positive for alpha-inhibin.

Adult↗
PubMed1999

Autoantibodies against oxidatively modified LDL do not constitute a risk factor for stroke: a nested case-control study.

BACKGROUND AND PURPOSE: Autoantibodies against oxidatively modified LDL have been shown to be associated with atherosclerosis. Their possible pathogenic role is not yet fully understood, and earlier published data are inconsistent. In this prospective study, we have investigated the association of these antibodies with future stroke. METHODS: A prospective case-control study in which 44 725 men and women from the World Health Organization Multinational Monitoring of Trends and Determinants in Cardiovascular Disease (MONICA) project and the Västerbotten Intervention Program (VIP) were enrolled and followed from January 1, 1985, to August 31, 1996. One hundred nineteen cases of stroke (male 75, female 44) were noted and compared with 233 age- and sex-matched controls from the same population. Antibodies against oxidatively modified LDL (copper-oxidized LDL and malonaldehyde [MDA]-LDL) were analyzed by ELISA. RESULTS: There was no difference in the levels or in the prevalence of IgG, IgA, and IgM autoantibodies against copper-oxidized LDL or MDA-LDL between patients and controls. Risk ratios for these antibodies, when adjusted for diabetes mellitus, hypertension, and smoking habits, did not confer a risk of stroke. Serum triglycerides (1.7 versus 1.4 mmol/L, P=0.01), fasting blood sugar, and systolic and diastolic blood pressures were significantly higher in the patient group than in the control group, as was the prevalence of hypertension (51.8% versus 27.4%, P<0.0001) and diabetes mellitus (9.6% versus 0.8%, P<0.001). CONCLUSIONS: Autoantibodies against oxidatively modified LDL do not constitute a risk factor for stroke in an adult population.

Adult↗
PubMed1996

The sequence of the Mycoplasma arthritidis superantigen, MAM: identification of functional domains and comparison with microbial superantigens and plant lectin mitogens.

Mycoplasma arthritidis, an agent of chronic proliferative arthritis of rodents, secretes a potent soluble superantigen, MAM, that is active for both murine and human T and B lymphocytes. We now report the complete nucleotide and amino acid sequence of MAM and show it to be distinct from other proteins and not closely related phylogenetically to other superantigens. Two functional domains on MAM are identified based on the ability of peptides encompassing these regions to inhibit lymphocyte proliferation by the intact MAM molecule. One of these domains shares short sequences or epitopes with other microbial superantigens. The second domain contains the consensus legume lectin motif-beta, which is important for T cell activation by concanavalin (Con) A. MAM and Con A peptides containing this motif are functionally cross reactive, suggesting a novel secondary pathway for T cell activation by MAM.

Amino Acid Sequence↗
PubMed1996

Acute renal failure due to traumatic rhabdomyolysis.

Between 1990 and 1993, we studied 14 cases of acute renal failure due to prolonged muscular exercise (e.g., squat jumping, sit-ups) and blunt trauma inflicted by law enforcement personnel using sticks or leather belts. None of the patients had a prior history of myopathy, neuropathy, or renal disease. All were critically ill and required renal support in the form of dialysis. Although the morbidity was high, 13 of the patients recovered normal renal function. One patient expired due to sepsis.

Acute Kidney Injury↗
PubMed1996

Acute renal failure of obstetrical origin during 1994 at one center.

Although preventable, acute renal failure (ARF) of obstetrical origin continues to be common in developing countries. During the year 1994, we treated a total of 238 cases of ARE. Of these cases, 43 (18%) were of obstetrical origin. All of the patients were known to be previously healthy. Acute renal failure occurred in association with antepartum hemorrhage in 15, postpartum hemorrhage in 10, intrauterine death of fetus in 11, preeclampsia or eclampsia in 9, and septic abortions or puerperal sepsis in 7. Thirty-six patients required dialysis therapy because of moderate to severe azotemia. Renal histology was studied in 12 cases. Acute cortical necrosis was present in 9, extensive tubular necrosis in 2, and 1 patient had membranoproliferative glomerulonephritis. Twenty-two (51%) patients recovered normal renal function, while 11 (26%) developed irreversible renal dysfunction and 10 (23%) expired. Mortality and morbidity in this region is still quite high in obstetrical situations. Poor health infrastructure and lack of antenatal health clinics leads to development of major complications at the time of childbirth, which is mostly conducted at home by untrained personnel in quite a few cities of the country.

Acute Kidney Injury↗
PubMed1996

Analysis of factors causing acute renal failure.

Factors leading to acute renal failure (ARF) were analysed in 376 consecutive patients between January 1993 and December, 1994 in a Karachi centre. Two hundred and sixteen (57%) had medical conditions, 86 (24%) obstetrical, 28 (7%) obstructive, 18 (5%) surgical and in 28 (7%) the causes were uncertain. Within the medical group, the causes were diarrhoea 30%, drugs 23%, malaria 15% and liver disease 5%. In the obstetrical group majority of the patients had multiple etiologies. Sixty percent of patients had ante-partum haemorrhage, 33% post-partum haemorrhage, intrauterine deaths were seen in 31%, septic abortions in 20% and pre-eclamptic toxemia in 22% cases. In the obstructive group, most of the patients had stone disease, where bilateral ureteric calculi constituted 57% of the cases. In surgical group, 11 (61%) had ARF due to post-operative complications. This data confirms the pattern of ARF from other third world countries where obstetrical and obstructive causes are high as compared to western countries.

Acute Kidney Injury↗
PubMed1993

Projections of the guinea-pig paracervical ganglion to pelvic viscera.

The uterine cervix, urinary bladder and rectum of guinea pigs were injected with Fast Blue dye for retrograde transport studies. Dye-laden neuronal perikarya were detected for each viscus in the paracervical ganglion. These same perikarya also exhibited immunoreactivities for tyrosine hydroxylase, aromatic amino acid decarboxylase, dopamine beta-hydroxylase, neuropeptide Y, or vasoactive intestinal peptide, though the perikarya projecting to the urinary bladder did not exhibit immunoreactivity for aromatic amino acid decarboxylase. The results of this study indicate that the guinea-pig paracervical ganglion projects to viscera in addition to the uterus, and that the ganglion contains a range of immunoreactivities related to adrenergic and non-adrenergic neurotransmitters.

Amidines↗
PubMed1993

Immunomodulation in vivo by the Mycoplasma arthritidis superantigen, MAM.

Mycoplasma arthritidis produces a potent superantigen (MAM) that activates specific murine and human T lymphocytes to proliferate and secrete lymphokines. We show here that MAM also influences both T- and B-cell functions in vivo. Lymphocytes from mice injected with MAM exhibit a suppression of proliferative responses to MAM in vitro but only a partial suppression of responses to other mitogens. This T-cell anergy not only decreased contact sensitivity to dinitrofluorobenzene but also prolonged survival of skin transplants. In contrast, B-cell reactivity is increased following in vivo injection of MAM, as evidenced by enhanced antibody responses to sheep red blood cells and ovalbumin. Also, there is a marked decrease in the ability of splenocytes from MAM-injected mice to produce interleukin-2 (IL-2) but a marked increase in their ability to produce IL-4 and IL-6. The combined results suggest that MAM induces a lymphokine profile that favors activation of B-cell functions, with a resulting potential for triggering of autoimmune disease.

Acquired Immunodeficiency Syndrome↗
PubMed1992

An immunohistochemical study of the catecholamine synthesizing enzymes and neuropeptides in the female guinea-pig uterus and vagina.

The uterus and vagina of the guinea pig have been examined, region by region, for acetylcholinesterase, tyrosine hydroxylase, dopamine beta-hydroxylase and aromatic amino acid decarboxylase activity, as well as for the neuropeptides, neuropeptide Y, vasoactive intestinal peptide, substance P, enkephalin and somatostatin. No acetylcholinesterase activity was localized in the uterus, though it was present in associated paracervical ganglion tissues. Of the catecholamine-synthesizing enzymes, tyrosine hydroxylase and dopamine beta-hydroxylase activity was found virtually throughout the reproductive tract, whereas aromatic amino acid decarboxylase activity was restricted in its distribution. Neuropeptide distribution was quite varied. Neuropeptide Y was found throughout the endometrium/submucosa but only in the muscularis of the vagina and not in the myometrium. Substance P was localized in the vagina and uterine horn, though not the body of the uterus. Vasoactive intestinal peptide was present in all regions of the endometrium/submucosa, but not in the myometrium of the uterine horn. Enkephalin and somatostatin were not localized in any part of the reproductive tract examined, apart from paracervical ganglion tissues. The types and significance of the nerves supplying the reproductive tract are discussed.

Acetylcholinesterase↗