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Biomedical subjects

K Rashid

Publications and source records attributed to K Rashid.

14 recordsLinked to original sources
PubMed2006

Reduced-dose rasburicase (recombinant xanthine oxidase) in adult cancer patients with hyperuricemia.

Recombinant urate oxidase (rasburicase) lowers uric acid levels rapidly to very low levels at the labeled dose of 0.15-0.2 mg/kg daily for 5 days. Our past experience showed that a lower dose (3 mg) lowered uric acid levels sufficiently in most patients. A retrospective review was conducted to determine the effect of a fixed 3 mg dose of rasburicase in 43 adult patients with cancer undergoing hematopoietic stem cell transplantation or receiving chemotherapy who had elevated or rising uric acid levels (6.4-16.8 mg/dl; median 9.6). Six patients received a second dose of rasburicase (3 mg in four patients and 1.5 mg in two patients) 24 h later. Patients received allopurinol, adequate hydration, as well as other supportive therapy as required. Uric acid levels declined by 6-95% (median 43%) within the first 24 h after rasburicase administration, and levels at 48 h were 9-91% (median 65%) lower than the baseline levels. Serum creatinine changed by < or =10% in 21 patients, increased by >10% in four patients and decreased by >10% in 18 patients. No significant renal dysfunction developed in any of the patients. We conclude that rasburicase is effective in lowering uric acid levels at a fixed dose of 3 mg, which is much lower than the recommended dose.

Adult↗
PubMed2005

Long-term survival of patients with resistant lymphoma treated with tandem stem cell transplant.

Dose-intensive chemotherapy with autologous stem cell support is commonly used in resistant/refractory cases of Hodgkin's disease (HD) and non-Hodgkin's lymphoma (NHL). The purpose of this study was to evaluate the role of tandem transplantation in these patients. We used non cross-resistant conditioning regimens with thiotepa, mitoxantrone and carboplatin (TMJ) followed by ifosphamide, carboplatin and etoposide (ICE) with autologous stem cell rescue in an attempt to maximize dose intensity and achieve long-term remission. Seventy-six patients were included in this study. Twenty-nine patients with HD and 47 with NHL underwent autologous stem cell transplant using TMJ as the conditioning regimen for the first transplant. Of these, 49 patients proceeded to the second transplant using ICE as the conditioning regimen. In 57 patients, only peripheral blood cells were used and in 11 patients both bone marrow and peripheral stem cells were used. Twelve patients died due to treatment-related toxicity. On an intent to treat basis, 32.14% of patients with HD refractory to initial or subsequent therapy survived long term as opposed to 12.76% of patients with NHL. With a median follow-up of 83 months (range 25 - 110 months), the median disease-free survival of patients with HD was 7 months, as opposed to 2 months for patients with NHL. Multivariate analysis identified that patients with HD had a superior outcome if they were less than 35 years of age and did not have B symptoms. Dose-intensive chemotherapy with tandem transplantation is an option in patients with resistant/refractory lymphoma who have very limited treatment options and poor prognosis.

Adult↗
PubMed1995

A nerve growth factor peptide retards seizure development and inhibits neuronal sprouting in a rat model of epilepsy.

Kindling, an animal model of epilepsy wherein seizures are induced by subcortical electrical stimulation, results in the upregulation of neurotrophin mRNA and protein in the adult rat forebrain and causes mossy fiber sprouting in the hippocampus. Intraventricular infusion of a synthetic peptide mimic of a nerve growth factor domain that interferes with the binding of neurotrophins to their receptors resulted in significant retardation of kindling and inhibition of mossy fiber sprouting. These findings suggest a critical role for neurotrophins in both kindling and kindling-induced synaptic reorganization.

Animals↗
PubMed1995

Intraventricular administration of antibodies to nerve growth factor retards kindling and blocks mossy fiber sprouting in adult rats.

Repeated subconvulsive electrical stimulation of certain areas of the forebrain leads to kindling, a progressive and permanent amplification of evoked epileptiform activity, which is a model for human temporal lobe epilepsy. Recent studies have shown that kindling induces synthesis of nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF) but not neurotrophin-3 (NT-3) in the hippocampus and cortex. Kindling also elicits mossy fiber sprouting and functional synaptogenesis in the supragranular layer, the hilus, and the CA3 region of the hippocampus. Intraventricular administration of antibodies to NGF has been shown to effectively block septohippocampal sprouting in the adult rat, and has been reported to retard amygdaloid kindling. In the present study, we have investigated the possible role of NGF in both kindling and kindling-associated sprouting. We have confirmed a kindling-induced sprouting of the mossy fibers into the stratum oriens of the CA3 region of the hippocampus, utilizing a new semiquantitative method of analysis based on Timm staining. Previous studies found no overt signs of hippocampal damage with this kindling paradigm, indicating that the increased Timm staining likely reflects a purely activity-induced sprouting. Intraventricular infusion of affinity-purified anti-NGF IgGs (which cross-react with NT-3 but not BDNF) resulted in both significant retardation of kindling and inhibition of the kindling-induced mossy fiber sprouting. The findings suggest a role for NGF in both these phenomena.

Animals↗
PubMed1994

Doppler study of the uterine artery in patients using an intrauterine contraceptive device.

A Doppler flow study of the uterine artery was performed using transvaginal sonography in 68 women, including 44 using an intrauterine contraceptive device (IUCD) and 24 control women who were not using any method of contraception. Both the pulsatility index (PI) and resistance index (RI) were significantly lower in women with IUCD-induced bleeding than in those without abnormal vaginal bleeding (p < 0.001) or in women not using any method of contraception (p < 0.001). No significant variations in PI and RI levels (p > 0.05) were found with the duration of IUCD application or the duration of IUCD-induced bleeding in patients using the device. Also, no significant changes in blood flow indices were demonstrated between women using the device without abnormal vaginal bleeding and the control group. These preliminary results suggest that some women are more prone to develop IUCD-induced bleeding than others, and this bleeding may be due to decreased vascular resistance in the uterine artery. Transvaginal Doppler study of the uterine artery may be a helpful technique to identify such women.

Journal Article↗
PubMed1993

Evidence for D2 receptor regulation of dopamine release in the goldfish retina.

The possible existence of a dopamine D2 receptor-mediated regulation of dopamine release was investigated in the goldfish retina. Isolated retinas were preloaded with [3H]dopamine and superfused with D2 dopamine receptor agonists or antagonists to determine if there was an effect on [3H]dopamine release. The D2 receptor antagonist sulpiride increased both baseline [3H]-dopamine release and [3H]dopamine release induced by an increase in extracellular potassium concentration. The D2 receptor agonists LY-171555 and RU-24213 did not reduce baseline [3H]dopamine release but completely inhibited [3H]dopamine release induced by an increase in [K+]o. This action of the D2 agonists was blocked by sulpiride. These studies demonstrate the existence of D2 receptor, possibly autoreceptor, regulation of dopamine release in the teleost retina.

Animals↗
PubMed1992

Antibacterial activity and mutagenicity studies of water-soluble phosphazene high polymers.

Eight water-soluble phosphazene high polymers, [NPR2]n (R, organic, water-solubilizing side-group; n, approx: 15,000) and the small-molecule counterparts of the polymers were examined for antibacterial activity against six different strains of bacteria (Escherichia coli, Salmonella typhimurium (TA 100), Salmonella pullorum, Streptococcus faecalis, Bacillus subtilis and Pseudomonas aeruginosa). Antibacterial testing was carried out by measuring zones of inhibition and changes in solution turbidity over time. In addition, the antibacterial activity of the surfaces of cross-linked poly[di(methoxyethoxyethoxy)phosphazene] (MEEP) hydrogels were investigated. A number of the high polymers, as well as the MEEP hydrogels, impeded bacterial growth. Only E. coli was unaffected by the phosphazenes. A possible explanation for the antibacterial character of the polymers is presented. The same compounds were monitored for potential mutagenic activity using the Salmonella typhimurium tester strains TA 100 and TA 98. None of the high polymers or their small-molecule analogues showed mutagenic activity in either strain of Salmonella at the concentrations tested. The use of these materials as coatings for artificial implants is discussed.

Anti-Bacterial Agents↗
PubMed1991

Quantitative high-performance liquid chromatography analysis of DNA oxidized in vitro and in vivo.

Oxidative modification of genetic material has been implicated as a factor in carcinogenesis, particularly during promotion and progression, and therefore there is a need for sensitive detection of oxidized DNA bases. We developed a method that can be applied to DNA isolated from any source and used to simultaneously quantify oxidized nucleosides without a need to prelabel the DNA or use destructive hydrolytic procedures. This method is based on: (a) enzymatic DNA digestion; (b) HPLC separation of the resultant nucleosides; (c) acetylation of the oxidized nucleosides with [3H]Ac2O (acetic anhydride); (d) removal of the radioactive debris; and (e) quantitative analysis of tritiated nucleoside acetates by HPLC. Enzymatic DNA digestion was optimized using DNase I in the presence of Mg2+ (pH 7), followed by nuclease P1 in the presence of Zn2+ (pH 5.1) and alkaline phosphatase (pH 7.5). Analysis of DNA oxidized with H2O2 in the presence of Fe2+/EDTA for 30 min showed that the levels of 8-OHdG (8-hydroxy-2'-deoxyguanosine) were increased 2.7-fold, HMdU (5-hydroxymethyl-2'-deoxyuridine) 3.15-fold, and FdU (5-formyl-2'-deoxyuridine) 2.5-fold. Although the (-)-isomer of cis-dTG (cis-thymidine glycol) was enhanced 2.3 times, the (+)-isomer remained virtually unchanged. Analysis of DNA isolated from epidermal cells of mice treated in vivo with the tumor promoter TPA (12-O-tetradecanoylphorbol 13-acetate) showed 4.8-, 2.7-, and 8.7-fold increases in the levels of total cis-dTG, 8-OHdG, and HMdU, respectively, and of some unknown DNA oxidation products. These results prove applicability of the 3H-postlabeling method to the analysis of DNA (and potentially RNA) isolated from many sources, including animals and humans.

Animals↗
PubMed1988

Blunted kaliuresis after an acute oral potassium load in diabetes mellitus.

It is unknown whether diabetic patients without renal failure or aldosterone deficiency respond normally to potassium administration. Acute oral potassium-loading was carried out in eight diabetic patients with modestly reduced creatinine clearance (Ccr) and in 11 diabetic patients and 13 controls with normal clearances. Only one diabetic patient manifested an inappropriately low upright plasma aldosterone level (6 ng/dL). The percentage of potassium excreted in 4 hour by both groups of diabetic patients was significantly less than that of the controls (decreased Ccr:21% +/- 6%, normal Ccr:36% +/- 5%, controls:54% +/- 5%; p less than 0.01 and 0.05 respectively). On the other hand, the estimated amount of potassium translocated intracellularly tended to be greater in the diabetic patients (18 +/- 3 mmol; 11 +/- 3 mmol) than controls(7 +/- 2 mmol; p less than 0.005 and 0.1 respectively), and the ratio of the increase in plasma (K) to the amount of potassium retained, was lower in diabetic patients, probably indicating enhanced intracellular potassium translocation. The authors conclude that diabetic patients with normal or only slightly reduced renal function (and no aldosterone deficiency) may have a reduced capacity to excrete an acute potassium load but an enhanced capacity to transfer potassium intracellularly.

Adult↗
PubMed1983

An active cytochrome c oxidase that has no tightly bound cardiolipin.

Bovine and dogfish (Squalus acanthias) heart submitochondrial particles and cytochrome c oxidase (EC 1.9.3.1) were prepared. Biphasic Eadie--Hofstee plots from steady-state polarographic assays were obtained for both species. Phospholipid analyses indicated that cardiolipin was absent from this active dogfish enzyme.

Animals↗