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Biomedical subjects

Z Ahmed

Publications and source records attributed to Z Ahmed.

At least 73 records · Page 4Linked to original sources
PubMed1997

Cartilage calcification and limb bud growth in the developing tich mouse embryo.

The tich mutation leads to the abnormal development of bones in mice such that a 'V-shaped' tongue of noncalcified cartilage appears in the central portion of the proximal tibial growth plate. In this study, alcian green staining of cartilage glycosaminoglycans was used to demonstrate the pattern of limb development in embryos of stage-matched tich and normal, co-isogenic, A.TL mice from the earliest stages in skeletogenesis. The growth plates of normal A.TL siblings were symmetrical across the limb rudiment whereas the growth plate in tich siblings show the beginnings of a V-shaped tongue of cartilage reaching towards the diaphysis. This showed first at E16.5. It was apparent that the crown rump distance, tibia, ulna, and the length of calcified cartilage in tich were significantly shorter than A.TL. These results confirmed that calcification was not the primary defect in tich but point to a temporal dysfunction in growth factor expression (possibly bone morphogenetic proteins) that stems from early limb bud formation and translates through later stages in development.

Animals↗
PubMed1997

Asymptomatic urinary abnormalities. Hematuria and proteinuria.

Asymptomatic urinary abnormalities including hematuria and proteinuria are commonly detected in routine urinalysis. They may be of benign etiology or indicative of more serious underlying disease. This article is intended to give clinicians a guide for evaluation of hematuria and proteinuria.

Hematuria↗
PubMed1997

Drug-induced nephrotoxicity.

Drug-induced renal dysfunction is not an uncommon event, which can cause significant morbidity and can be easily overlooked. Many medications can lead to renal dysfunction through various mechanisms. The most common medications or classes of medications along with their clinical presentations are discussed in this article. As can be noted, many drugs can cause nephropathy in more than one way. Because it is difficult to discuss nephrotoxicities of every reported medication, Tables 1, 2, and 3 are provided; although these tables are by no means comprehensive, they may serve as further reference. This article is intended to provide a broad overview of the spectrum of presentation associated with drug-induced nephrotoxicity to guide the clinician to familiarity with this entity.

Acute Kidney Injury↗
PubMed1997

Learning disabilities: moving forward--a focus on epilepsy, Birmingham, England, 29 June 1996.

On 29 June 1996 a conference was held in Birmingham to highlight the status of epilepsy in people with learning disabilities. The conference consisted both of seminars and workshops. Dr Tim Betts, Birmingham; Dr Greg O'Brien, Northumberland; and Dr Mike Kerr addressed issues of assessment, diagnosis and drug treatment of epilepsy in this population. This meeting report summarizes the proceedings of the conference.

Anticonvulsants↗
PubMed1997

Complete gastric outlet obstruction following acid ingestion complicated by acute pancreatitis and disseminated intravascular coagulation.

A case is described where accidental acid ingestion resulted in the development of oesophageal stricture and complete gastric outlet obstruction. Following a smoothly conducted pre-surgery endoscopic examination the patient developed acute pancreatitis, which, on initial clinical examination, was diagnosed as a viscus perforation. The severity of pancreatitis was such as to lead to disseminated intravascular coagulopathy and ultimately death. The interest lies in the fact that pancreatitis was precipitated in a previously traumatised stomach by such an innocuous procedure as fibre-optic endoscopy.

Acids↗
PubMed1996

Deep vein thrombosis as a predictor of cancer.

An association between cancer and venous thrombosis has long been recognized. In an attempt to find whether venous thrombosis can serve as a reliable predictor of subsequent cancer, 196 cases of confirmed venous thrombosis treated over a seven-year period were reviewed. Of a total of 196 cases, 113 were found to suffer from primary type deep venous thrombosis (DVT), whereas 83 were allocated to secondary type DVT. Of 113 cases with primary DVT, 23 had suffered from recurrent episodes, whereas 90 had only a single episode. From the secondary DVT group of 83 patients, 14 suffered from recurrent episodes and 69 had a single episode. Of the patients in the primary DVT group, 2.65% (3/113) developed cancer subsequently, whereas none was detected among the group of 83 patients who had secondary DVT. In the group of 113 patients with primary DVT, the incidence was higher among those who had recurrent episodes (4.34%, 1/23) than among those who had a single episode (2.22%, 2/90). The overall incidence of cancer among 196 cases of DVT was found to be 1.53% (3/196). The findings do not support the routine screening of all DVT patients by expensive diagnostic modalities. These patients should rather be assessed by careful clinical examinations and baseline investigations. The detailed investigations should be resorted to if there is any suggestion of presence of occult malignancy by these simpler means. One should be more vigilant in case of patients suffering from primary type DVT, for the incidence in this group is significantly higher.

Adult↗
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

Graft surveillance and angioplasty prolongs dialysis graft patency.

BACKGROUND: In the United States of America, vascular access complications are the most frequent cause of death among patients with end-stage renal disease on hemodialysis. The majority of American patients with end-stage renal disease have prosthetic grafts for access. The most common complication of prosthetic graft fistulas is thrombosis. To prolong graft life and decrease the frequency of operations, a university-based dialysis unit adopted a policy of graft surveillance by measuring venous resistance, followed by fistulagram and percutaneous dilatation of identified stenoses. The purpose of this retrospective study is to determine if this policy affected graft patency and graft life. STUDY DESIGN: This retrospective review compares outcomes for two years before adoption of this policy (control group, 210 patients) with the outcomes for three years after adoption (study group, 260 patients). Fifty (24 percent) of the control group and 71 (27 percent) of the study group were defined as "complicated" patients because they underwent more than one intervention over any 12-month period. RESULTS: The 50 complicated patients in the control group underwent 104 operations for thrombosis over two years, 1.04 thrombotic episodes and operations per patient year. Seventy new grafts were placed with a mean primary patency of 3.9 months. Mean graft survival time was 6.3 months. The 71 complicated patients in the study group underwent 111 fistulagrams, 80 angioplasties, and 110 operations over three years, for 0.52 thrombotic episodes per patient year (p < .001). Forty-five new grafts were placed with a primary patency of 11.5 months (p < .001). Mean graft survival time was 15.8 months (p < .001). CONCLUSIONS: This retrospective study demonstrates the effectiveness of a policy of graft surveillance and percutaneous treatment of graft stenosis in prolonging primary surgical patency and graft survival.

Angioplasty, Balloon↗
PubMed1995

Correlation of venography, venous pressure, and hemoaccess function.

We analyzed the anatomic features of both grafts and fistulas and correlated these features with access function. We also attempted to determine venous pressures predicting access dysfunction (critical venous pressures) at various blood flow rates (BFRs). Therefore, accesses of 46 chronic hemodialysis patients were studied by venography in a prospective fashion. We defined the incidences of various lesions and the effects of venous collaterals on graft function, and determined critical venous pressures at various BFRs. Eighty-three percent of the accesses had outflow obstruction. Five types of anatomic lesions were identified. The incidences were venous stenosis of the draining vein immediately proximal to the venous anastomosis, 36.4%; central vein, 23.6%; venous anastomosis, 25.5%; arterial anastomosis, 10.9%; and intragraft hyperplasia, 3.6%. Twelve patients had multiple lesions. When the homogenous polytetrafluoroethylene arm graft population was studied for the effect of venous collaterals, we found that venous collaterals conferred protection but did not prevent graft failure. Venous pressure measurements were good predictors of access failure at the lower BFRs. Venous pressures increased with increasing BFRs. A critical venous pressure of 145 mm Hg was found for a BFR of 250 mL/min. At a BFR of 300 mL/min, the critical venous pressure was 170 mm Hg. A critical venous pressure could not be found for a BFR of 400 mL/min.

Arteriovenous Shunt, Surgical↗
PubMed1995

Cell proliferation within the growth plate of the tich mouse.

The pattern of chondrocyte proliferation was studied in the proximal tibial growth plate of tich mice (gene symbol tch), a recessive mouse mutant, which is coisogenic with the A.TL strain. Specimens were qualitatively studied at time points of 2, 3, 4, 6, and 8 weeks of age by bromodeoxyuridine labeling of cell division and routine histology. At 2 weeks, when the lesion appeared as a full-width thickening of the growth plate, a greater proportion of cells appeared positively labeled in the proliferative zone. This concavity in the central portion of the growth plate became progressively more focal between 3 and 4 weeks to give a "tongue" of unresorbed, noncalcified cartilage in the central region of the tich growth plate. BrdUrd labeling indicated that the appearance of the cartilage tongue corresponded with increased cell division in the central region of the growth plate. At the same time, a "second" zone of cell division formed, within the zone of hypertrophy, such that labeled cells appeared to be set among chondrocytes with hypertrophic morphology. At stages after 4 weeks of age the focal feature disappeared as the growth plate returned to more normal morphology by maturity. It seems that this unique "second" zone of dividing cells may contribute to formation of an elongation of the nonresorbed tongue of cartilage. However, it is not likely to be the primary defect since growth plate changes were apparent at earlier stages.

Animals↗
PubMed1995

Management of flail chest injury: internal fixation versus endotracheal intubation and ventilation.

A total of 427 patients with major chest trauma were treated in two major hospitals in Abu Dhabi, United Arab Emirates, during a 10-year period. In 64 of 426 patients, flail chest injury was the dominant factor among other injuries that were insignificant. Among 64 cases of flail chest injury, 25 were managed by internal fixation of ribs, whereas the remaining 38 were managed by endotracheal intubation and intermittent positive-pressure ventilation alone. Of the patients treated by internal fixation 80% (21/26) were weaned from the ventilator within an average of 1.3 days, whereas the remaining 20% (5/26) continued to need assisted ventilation for a longer duration; the total average duration of assisted ventilation for the whole group was 3.9 days. In comparison, among 38 patients with flail chest injury treated by endotracheal intubation and ventilation alone, the average duration of assisted ventilation was 15 days. In the group treated by internal fixation 11% (3/26) of the patients ultimately required a tracheotomy, whereas in the patients treated by intubation and ventilation alone tracheostomy was required in 37% (14/38) of the cases. In the group treated by internal fixation, chest infection was documented in 15% (4/26), septicemia in 4% (1/26), and barotrauma in 0%; in the other group these complications occurred in 50% (19/38), 24% (9/38), and 8% (3/38) of the cases, respectively. The mortality rate was 8% (2/26) in the surgically treated patients, whereas it was 29% (11/38) in the other group. All the deaths in both groups were ascribed to adult respiratory distress syndrome. Average stay in the intensive care unit was 9 days for the patients treated by internal fixation, whereas it was 21 days in the group treated by intubation and ventilation alone. The treatment of flail chest injury in our series by internal fixation resulted in speedy recovery, decreased complications, and better ultimate cosmetic and functional results and proved to be cost effective.

Adolescent↗
PubMed1993

New saponins from Mangifera indica.

Two new terpenoidal saponins, indicoside A [1] and indicoside B [2], were isolated from Mangifera indica. Their structures were determined as 28-hydroxylupa-12,20(29)-diene-3-O-[beta-glucopyranosyl-(1-->2)] [-beta-glucopyranosyl-(1-->3)]-alpha-L-arabinopyranoside [1] and 28-hydroxylupa-12,20(29)-diene-3-O-[beta-glucopyranosyl-(1-->3)-al pha-L-rhamnopyranosyl-(1-->2)][beta-glucopyranosyl(1-->3)]-alpha-L- arabinopyranoside [2] on the basis of chemical and spectroscopic studies.

Carbohydrate Sequence↗
PubMed1993

Endothelin activation of phospholipase D: dual modulation by protein kinase C and Ca2+.

Previous work from this laboratory has identified an endothelin (ET) type A (ETA) receptor on cultured rat renal medullary interstitial cells (RMIC), coupled to phosphatidylinositol-specific phospholipase C (PI-PLC), dihydropyridine-insensitive receptor-operated Ca2+ channels, and phospholipase A2. The current studies explored a role for ET stimulation of phosphatidylcholine-specific phospholipase D (PC-PLD) in intracellular signaling of this cell type. ET stimulated PLD activation, as measured by phosphatidic acid (PA) or phosphatidylethanol (PEt) accumulation, in a time- and concentration-dependent manner. Inhibition of diacylglycerol (DAG) kinase by ethylene glycol dioctanoate or 6-(2)4-[(4-fluorophenyl)-phenylmethylene]-1-piperadinyl]ethy l-7-methyl-5H - thiaxolo-[3,2-alpyrimidin]-5-one (R 59022) failed to blunt PA accumulation, indicating that PLD, and not DAG, was the source of PA. Inhibition of PA phosphohydrolase (PAP) by propranolol increased late accumulation of PA, suggesting that the prevailing metabolic flow was in the direction of PA to DAG. Phorbol 12-myristate 13-acetate (PMA) augmented ET-evoked PEt accumulation, whereas downregulation of protein kinase C (PKC) obviated agonist-induced PEt production. PMA augmentation of PLD activity proceeded independent of cytosolic free Ca2+ concentration. Ca2+ derived from either intracellular or extracellular sources enhanced ET-related PEt accumulation but was without effect in PKC-downregulated cells. Collectively, these observations indicate that ET stimulates PLD production in RMIC. PKC is the major regulator of this process, with Ca2+ playing a secondary, modulatory role. In addition, these data suggest that PC-PLD is coupled to the ETA receptor.

Animals↗