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Biomedical subjects

N Ismail

Publications and source records attributed to N Ismail.

At least 37 records · Page 2Linked to original sources
PubMed1996

Water treatment for hemodialysis.

Water treatment is a vital aspect of hemodialysis in which knowledge and technical skills are of utmost importance. The recognition that nontuberculous mycobacteria can be resistant to certain germicides spurred the establishment of the current safety microbiologic standards for dialyzer reprocessing. Monitoring the dialyzer membrane integrity is as important as meeting the standards for bacterial and endotoxin levels for dialyzer reprocessing. Ensuring the use of product water that meets the chemical and microbiologic standards of the Association for the Advancement of Medical Instrumentation is necessary to reduce the incidence of endotoxemia and chemical hazards associated with the use of water for hemodialysis. The pathogenesis of febrile reactions during hemodialysis remains controversial. The weight of evidence, however, favors transmission of endotoxin fragments across dialysis membranes to induce mononuclear cell cytokine production.

Dialysis Solutions↗
PubMed1996

Renal transplantation in the older end stage renal disease patient.

Transplant physicians in the United States continue to face an interesting problem when offering kidney transplantation as a form of renal replacement therapy to older end-stage renal disease (ESRD) patients. The limited life-expectancy of these patients and an ever-present shortage of cadaveric organs makes kidney transplantation in this population a potentially controversial issue. Early results suggested poor outcomes for cadaveric renal transplantation in middle-aged or elderly ESRD patients. Improved patient selection, changes in immunosuppression regimens, and living-related transplantation have increased the success of transplantation in these patients. Efforts to define older patients at risk for cardiovascular disease and to account for their altered immune function may further improve outcomes. However, if older ESRD patients are to be rightfully included in the patient population eligible for transplantation, then the organ shortage will inevitably worsen. A potentially intriguing solution to this problem is to expand the donor pool by including older donors. Despite data suggesting that recipients of older grafts may have shorter graft survival; older donors could readily serve as a source of kidneys for older recipients who do not require 20+ year graft survival based upon their projected lifespan. Ultimately, age alone should not serve as a contraindication to renal transplantation. In patients over the age of 60, 1-year patient and graft survival rates approach 85% and 75%, respectively. However, careful assessment of "biologic" age and comorbid illnesses should be considered when offering renal transplantation to older patients.

Aged↗
PubMed1995

Abnormal uterine bleeding on hormone replacement: the importance of intrauterine structural abnormalities.

OBJECTIVE: To examine the importance of submucous myomas and endometrial polyps before and after menopause and in abnormal withdrawal bleeding on hormone replacement therapy (HRT). METHODS: Between May 1991 and May 1993, women presenting with abnormal withdrawal bleeding on HRT (n = 106), menstrual problems in pre-menopause (n = 92), or postmenopausal bleeding (n = 33) underwent diagnostic outpatient hysteroscopy for the presence of intrauterine structural abnormalities. The findings were compared with a control group of post- and perimenopausal women without bleeding problems (n = 183). RESULTS: When compared with women who had normal uterine cavities, the presence of submucous myomas was associated with a threefold increase in the risk of abnormal menstrual bleeding in premenopausal women (odds ratio [OR] 3.34, 95% confidence interval [CI] 1.77-6.43; P < .001) and a twofold increase in the risk of abnormal withdrawal bleeding in post- and perimenopausal women (OR 2.4, 95% CI 1.25-4.53; P = .004). This did not seem to be related to the number of myomas detected. The frequency of endometrial polyps was not found to be significantly higher in women who had menstrual disorders or abnormal withdrawal bleeding on HRT. Postmenopausal bleeding without hormonal stimulation was not significantly associated with submucous myomas or polyps. CONCLUSION: As increasingly more women request HRT, bleeding problems presenting pre-menopause can no longer be expected to resolve "naturally" after menopause. In the presence of submucous myomas, these women will continue to have a higher risk of abnormal withdrawal bleeding when treated with hormone replacement, whereas endometrial polyps are not associated with an increased bleeding risk. Hysteroscopic assessment of the uterine cavity and subsequent counseling as to the risk of heavy or prolonged bleeding will be helpful in their future management and may improve compliance.

Adult↗
PubMed1995

Efficacy of oral iron therapy in patients receiving recombinant human erythropoietin.

Iron supplementation is required by most dialysis patients receiving recombinant human erythropoietin. The efficacy of oral iron is variable in these patients, and many require the use of intravenous iron dextran to maintain adequate iron levels, defined as transferrin saturation greater than 20%, serum ferritin greater than 100 ng/mL, and serum iron greater than 80 micrograms/dL. To determine the efficacy of different oral iron preparations in maintenance of iron status, we prospectively studied 46 recombinant human erythropoietin-treated patients and randomized them to receive different oral iron preparations. These four preparations included Chromagen (ferrous fumarate; Savage Laboratories, Melville, NY), Feosol (ferrous sulfate; SmithKline Beecham, Inc, Pittsburgh, PA), Niferex (polysaccharide; Central Pharmaceuticals, Inc, Seymour, IN), or Tabron (ferrous fumarate; Parke-Davis, Morris Plains, NJ). All patients were prescribed approximately 200 mg of elemental iron daily of their assigned iron preparation with at least 100 mg ascorbic acid daily for 6 months. At baseline and bimonthly during the study, serum iron, transferrin saturation, ferritin, hematocrit, and recombinant human erythropoietin dose were monitored; in addition, compliance and side effects were recorded by patient interview. All patients were able to maintain target hematocrit during the 6 months of study. However, there were differences in the trends of serum iron, percent transferrin saturation, and ferritin when considered singly or in combination between the four groups of iron medications. The percent of laboratory values measured over the study period in each group that met the criteria of transferrin saturation more than 20% was greatest in the Tabron group (58%), followed by the Feosol (47%), Chromagen (33%), and Niferex (31%) groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗
PubMed1995

Evaluation of BCG vaccination: an intervention study in Rail Region, Saudi Arabia.

Inspection of 300 infants attending a primary health care (PHC) center at Hail region showed that 18.8% of children failed to develop BCG reations. This directed attention to inspect the process of vaccination at hospitals in which 80% of deliveries and BCG vaccination took place. Defects in the process of vaccination and cold chain system were noticed. Reorganization of the process of vaccination in addition to training the staff responsible for vaccination were done. A survey was followed to evaluate failure of BCG vaccination before and after the intervention. We checked 4145 infants two to twelve months of age, for any reaction at the site of BCG vaccination. After intervention vaccination failure dropped from 20.4% to 4.9% for infants vaccinated in hospitals (p = 0.00001), and from 7.9% to 3.2% for those vaccinated in health centers (p = 0.01). Moreover, before intervention success of BCG vaccination was significantly higher in PHC centers (92.1%) than in hospitals (79.6%). This difference became insignificant after intervention because success of BCG vaccination in hospitals has increased up to 95.1% compared to 96.8% in health centers. Inspection of all infants for BCG reaction is continued as a part of routine work at PHC centers, and re-vaccination of those who failed to develop reation to BCG is conducted without any reported complications.

BCG Vaccine↗
PubMed1994

Effects of dose of dialysis on morbidity and mortality.

The annual mortality rate of patients on hemodialysis in the United States is 24.3%, substantially higher than the mortality of age-matched patients in Europe and Japan. Differences in the dose of dialysis received by US patients has been proposed as an important factor contributing to this high mortality rate. We undertook a prospective effort to increase the dose of dialysis delivered to 130 patients treated at an urban dialysis center affiliated with Vanderbilt University. From 1988 to 1991 the dose of dialysis, represented by the urea kinetic modelling parameter Kt/V (K = dialyzer clearance, t = dialysis time, V = volume of distribution of urea), has been gradually increased from a dose of 0.82 +/- 0.32 to 1.33 +/- 0.23. Concurrent with this increase, there was a reduction of the gross annual mortality rate from 22.8% in 1988 to 9.1% in 1991. To account for potential differences in patient characteristics during those years, we also calculated the number of expected deaths, based on data from the United States Renal Data System. The ratio of observed to expected deaths, termed the "standardized mortality rate," decreased from a value of 1.03 in 1988 to a value of 0.611 in 1991. In addition, the number of hospital days per patient per year decreased from 15.2 d/patient/yr to 10.3 d/patient/yr. We conclude that increasing the dose of delivered dialysis decreases the hospitalization and mortality rates of hemodialysis-dependent patients.

Adult↗
PubMed1994

Extrarenal complications of the nephrotic syndrome.

The systemic complications of nephrotic syndrome are responsible for much of the morbidity and mortality seen with this condition. This review discusses the causes for the hypoalbuminemia and the associated metabolic abnormalities of the nephrotic syndrome. No unifying hypothesis exists for the induction, maintenance, and resolution of nephrotic edema. In view of the wide spectrum of renal diseases leading to the nephrotic syndrome, more than a single mechanism may be responsible for the renal salt retention in these diverse conditions. Although hypoalbuminemia may be important, especially when plasma oncotic pressure is very low (serum albumin < 1.5 to 2.0 g/dL), primary impairment of salt and water excretion by the nephrotic kidney appears to be a major factor in pathogenesis of the edema. However, the decreased serum albumin and/or oncotic pressure seen with nephrotic syndrome is a major contributing factor to the development of the hyperlipidemia of nephrotic syndrome. Patients with unremitting nephrotic syndrome should be considered for combined dietary and lipid-lowering drug therapy. Urinary losses of binding proteins lead to the observed abnormalities in the endocrine system and in trace metals, and urinary losses of coagulation factors contribute to the hypercoagulable state. At present, selective renal venography is recommended when the suspicion of renal vein thrombosis is justified by clinical presentation. The impact on renal function caused by treating asymptomatic chronic renal vein thrombosis is undetermined, but anticoagulation for chronic renal vein thrombosis is associated with relatively few complications.

Acute Kidney Injury↗
PubMed1994

Renal replacement therapies in the elderly: Part II. Renal transplantation.

The United States end-stage renal disease (ESRD) population is growing progressively older. As a percentage of the overall ESRD population, the number of patients 65 years of age and older approached 40% by 1989. However, the percentage of ESRD patients with a functioning transplant was only 2.7% in this age group. Success of transplantation in geriatric ESRD patients over the last decade is due to improved patient selection as well as the use of cyclosporine A and lower doses of corticosteroids, with the achievement of 1-year patient and graft survival rates of 85% and 75%, respectively. For patients older than 60 or 65 years, the 5-year "functional" graft survival is 55% to 60%. Although overall results are excellent, the management of transplantation in the elderly requires an understanding of pharmacology, immunology, and physiology peculiar to this age group. Since the elderly have a degree of immune incompetence, they require less aggressive immunotherapy. Elderly patients have decreased hepatic enzyme activity, especially the P450 system, and therefore require a lower cyclosporine dose. Although elderly patients experience less rejection episodes than younger patients, graft loss in the elderly transplant recipient is due mainly to patient death. Most common causes of death in the elderly transplant recipient are cardiovascular disease and infection related to peaks of immunosuppression. Shortage of cadaver kidneys and limited life expectancy of the geriatric ESRD patient make allocation of cadaver kidneys to patients over 70 years (and even 65 years) a controversial issue and an ethical dilemma. Use of elderly cadaver donors (over 55 to 60 years) is associated with inferior success rates and is not an optimal solution to shortage of cadaver kidneys.

Aged↗
PubMed1994

The neuroleptic malignant syndrome and acute renal failure.

Rhabdomyolysis is a clinical disorder arising from skeletal muscle injury. Many potentially fatal complications may develop after rhabdomyolysis, including hyperkalemia, disseminated intravascular coagulation, and acute renal failure. Both traumatic and nontraumatic causes of rhabdomyolysis are seen. Frequently, nontraumatic rhabdomyolysis is associated with the use of common drugs. We report such a case--a patient afflicted with the neuroleptic malignant syndrome (NMS). NMS is characterized by fever, muscle rigidity, and neurologic changes after treatment with neuroleptic agents such as haloperidol. These symptoms may progress to rhabdomyolysis and acute renal failure. Many similar disease entities, especially those that display hyperpyrexia, resemble NMS. Thus, the diagnosis should rest on pertinent history as well as the recognition of these relevant clinical signs. Treatment should be directed toward averting the systemic complications of drug-induced rhabdomyolysis and renal failure. Discontinuation of the neuroleptic medication is imperative. Aggressive iv hydration, systemic and urine alkalinization, and therapy for life-threatening electrolyte abnormalities are all appropriate additional therapeutic goals. The use of dantrolene or bromocriptine may hasten recovery from NMS. Although mortality from NMS alone is unusual, NMS with concomitant renal failure carries a worse prognosis. The treatments outlined here may avert progressive renal failure and reduce mortality in patients with NMS-induced rhabdomyolysis and renal failure.

Acute Kidney Injury↗
PubMed1993

Renal replacement therapies in the elderly: Part 1. Hemodialysis and chronic peritoneal dialysis.

Recent demographic data from the United States and Europe demonstrate that the dialysis population is growing progressively older. In the United States the median age at onset of end-stage renal disease (ESRD) had reached 61 years in 1990, and the fraction of ESRD patients older than 65 years will approach 60% by the year 2000. The primary treatment of geriatric ESRD is center hemodialysis (82% of elderly patients). Chronic peritoneal dialysis in this age group is limited in the United States to less than 10%. Only 2.7% of elderly patients have a functioning transplant. Despite their complex medical and psychosocial conditions, survival and rehabilitation are acceptable in the elderly dialysis patient and these patients tend to be more complaint. Five-year dialysis patient survival rates in the United States are 19% and 10%, respectively, for the 65 to 74 and 75 to 84 age groups compared with 32% and 19%, respectively, for the same age groups in Europe. Five-year survival, particularly in the elderly, is even higher in Japan. Several factors favor the delivery of low doses of hemodialysis in the elderly and discontinuing dialysis is more common in the elderly. Continuous ambulatory peritoneal dialysis is a satisfactory alternative treatment modality for geriatric ESRD. Most studies confirm that survival of elderly patients on continuous ambulatory peritoneal dialysis and hemodialysis is similar. The 1991 United States Renal Data System report showing higher mortality among diabetic continuous ambulatory peritoneal dialysis patients than among hemodialysis patients may reflect selection of such patients, who may have more co-morbid conditions. In special cases, continuous cyclic peritoneal dialysis can be an alternative treatment for elderly ESRD patients.

Age Factors↗
PubMed1992

Effects of vitamin A deficiency on the inter-Sertoli cell tight junctions and on the germ cell population.

When 20-day-old rats are placed on a vitamin A deficient diet (VAD) for a period of 10 weeks, the seminiferous tubules are found to contain only Sertoli cells, a few residual A0, A1 spermatogonia, and preleptotene spermatocytes (PL). The type A1 spermatogonia and PL spermatocytes are arrested in their G2 phase. In VAD rats type A2-A4, intermediate (In) and B spermatogonia and all types of spermatocytes (except PL spermatocytes) and spermatids are eliminated from the seminiferous tubules. Two questions were raised in this investigation: 1) Is there, in VAD rats, any correlation between a breakdown of the blood-testis barrier (e.g., Sertoli cell tight junctions) and germ cell loss? 2) Is the disappearance of most germinal cells due to their degeneration during spermatogenesis or to a maturation depletion process resulting from an arrest of spermatogenesis at the spermatogonial stage? To investigate these questions four groups of male Sprague-Dawley rats (20-days old) were fed a VAD diet for 7 to 12 weeks. The testes were fixed by perfusion with 2.5% glutaraldehyde in 0.1 M sodium cacodylate containing 2% lanthanum nitrate, an electron opaque tracer used to test the patency of Sertoli cell tight junctions. The lanthanum permeated the intercellular space of the basal compartment but was arrested by normal inter-Sertoli cell tight junctions. The seminiferous epithelium showed numerous degenerating germ cells, some being internalized by Sertoli cells as membrane-bound phagosomes.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

Enhanced incorporation of [14C]glucosamine into glycosaminoglycans of aortic neointima of balloon-injured and cholesterol-fed rabbits in vitro.

Glycosaminoglycans (GAG), which form the elementary constituent of extracellular matrix proteoglycans (PG), are implicated in the pathogenesis of atherosclerosis, mainly due to their lipoprotein binding capability and their abundance in a developing lesion during atherogenesis. However, the reasons for the increment of GAG content are poorly understood. In the present study, the influence of two well known atherogenic factors on arterial GAG synthesis were examined by estimating the incorporation of [14C]glucosamine into aortic GAG in an in vitro incubation system. Radioactivity associated with GAG was taken to represent their synthesis. GAG synthesis by neointimal tissue of rabbit aortas, 12 weeks following balloon catheter deendothelialization was measured and compared in rabbits fed a normal or 0.25% cholesterol supplemented diet for the preceding 6 weeks. In normolipaemic rabbits synthesis was found to be 12,438 +/- 173, 17,884 +/- 1390 and 15,960 +/- 1355 dpm/mg dry defatted tissue from uninjured (control), deendothelialized (DEA) and reendothelialized (REA) areas of rabbit aortas, respectively. This incorporation of radioactivity was significantly greater in hypercholesterolaemic rabbits corresponding to 13,426 +/- 239, 32,670 +/- 3077 and 27,496 +/- 3287 in the control, DEA and REA, respectively. The results demonstrated a synergistic effect of cholesterol feeding and arterial endothelial denudation in stimulating GAG synthesis. Although GAG synthesis was found to be stimulated by either cholesterol feeding or arterial injury, the stimulation by cholesterol feeding alone was only marginal. Further, results show a much higher retention of newly synthesized GAG by the tissue from REA. This study provided a possible explanation for increased GAG content in a developing proliferative lesion.

Animals↗
PubMed1990

Role of spermatogonia in the stage-synchronization of the seminiferous epithelium in vitamin-A-deficient rats.

After 20-day-old rats are placed on a vitamin-A-deficient diet (VAD) for a period of 10 weeks, the seminiferous tubules are found to contain only Sertoli cells and a small number of spermatogonia and spermatocytes. Retinol administration to VAD rats reinitiates spermatogenesis, but a stage-synchronization of the seminiferous epithelium throughout the testis of these rats is observed. In order to determine which cell type is responsible for this synchronization, the germ cell population has been analyzed in whole mounts of seminiferous tubules dissected from the testes of rats submitted to the following treatments. Twenty-day-old rats received a VAD diet for 10 weeks and then were divided into three groups of six rats. In group 1, all animals were sacrificed immediately; in group 2, the rats were injected once with retinol and sacrificed 3 hr later; in group 3, the rats were injected once with retinol, placed on a retinol-containing diet for 7 days and 3 hr, and then sacrificed. Three rats from each group had one testis injected with 3H-thymidine 3 hr (groups 1 and 2) or 7 days and 3 hr (group 3) before sacrifice. Three normal adult rats (approximately 100 days old) served as controls. Labeled and unlabeled germinal cells were mapped and scored in isolated seminiferous tubules. In group 1, type A1 and type A0 spermatogonia as well as some preleptotene spermatocytes were present; type A2, A3, A4, In, and B spermatogonia were completely eliminated from the testis. Neither type A1 mitotic figures nor 3H-thymidine-labeled-type A1 nuclei were seen.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1987

Allograft and antibody responses of 15I5-B congenic chickens.

Seven congenic lines of chickens that differ from the parental inbred line RPRL-15I5 for genes in the major histocompatibility (B) complex are under development. After 2 to 5 generations of crossing B-homozygous chickens were produced for interim histocompatibility and antibody competence tests. Chickens in each of the B-congenic lines had antigens determining rapid skin graft rejection and stimulation of mixed lymphocyte responses by 15I5 chickens. Several lines repeatedly developed different antibody responses after immunization with sheep red blood cells, killed Brucella abortus, and Infectious Bursal Disease Virus Vaccine.

Animals↗
PubMed1976

The distribution of serotypes of Escherichia coli in cow-pats and other animal material compared with serotypes of E. coli isolated from human sources.

The serotypes of 13,139 strains of Escherichia coli isolated from humans were compared with the serotypes of 1076 strains isolated from animals. 689 of these strains were isolated from fresh cow-pats on 22 sites in England and Wales. 708 different O/H combinations were found. Of these, 520 were found in human strains only, 130 from animal strains only and 58 O/H serotypes from humans and animals. Approximately half of the animal strains could not be typed with the full set of sera used.

ABO Blood-Group System↗