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Biomedical subjects

Z Hassan

Publications and source records attributed to Z Hassan.

At least 37 records · Page 2Linked to original sources
PubMed2000

Antimicrobial, antioxidant, antitumour-promoting and cytotoxic activities of different plant part extracts of Garcinia atroviridis griff. ex T. anders.

Crude extracts (methanol) of various parts, viz. the leaves, fruits, roots, stem and trunk bark, of Garcinia atroviridis were screened for antimicrobial, cytotoxic, brine shrimp toxic, antitumour-promoting and antioxidant activities. The crude extracts exhibited predominantly antibacterial activity with the root extract showing the strongest inhibition against the test bacteria at a minimum inhibitory dose (MID) of 15.6 microg/disc. Although all the extracts failed to inhibit the growth of most of the test fungi, significant antifungal activity against Cladosporium herbarum was exhibited by most notably the fruit (MID: 100 microg), and the leaf (MID: 400 microg) extracts. None of the extracts were significantly cytotoxic, and lethal towards brine shrimps. The root, leaf, trunk and stem bark extracts (except for the fruits) showed strong antioxidant activity exceeding that of the standard antioxidant, alpha-tocopherol. Antitumour-promoting activity (>95% inhibition) was shown by the fruit, leaf, stem and trunk bark extracts.

Animals↗
PubMed2000

The effect of busulphan on the pharmacokinetics of cyclophosphamide and its 4-hydroxy metabolite: time interval influence on therapeutic efficacy and therapy-related toxicity.

Busulphan and cyclophosphamide (Bu/CP) are widely used in preparative regimens for bone marrow transplantation. Many studies have shown a wide variation in busulphan pharmacokinetics. Moreover, higher rates of liver toxicity were reported in Bu/CP protocols than in a total body irradiation (TBI)-containing regimen. In the present paper we investigated the effect of the time interval between the last dose of busulphan and the first dose of cyclophosphamide on the pharmacokinetics of CP and its cytotoxic metabolite 4-hydroperoxycyclophosphamide (4-OHCP). Thirty-six patients undergoing bone marrow transplantation (BMT) were included in the study. We also investigated the occurrence of veno-occlusive disease, mucositis and graft-versus-host disease. Ten patients conditioned with CP followed by TBI served as a control group (TBI). Twenty-six patients were conditioned with Bu/CP. The patients received Bu (1 mg/kg x 4 for 4 days), followed by CP (60 mg/kg for 2 days) administered as a 1-h infusion. Patients received their CP therapy either 7-15 h (group A, n = 12) or 24-50 h (group B, n = 14) after the last dose of Bu. None of the patients were given phenytoin or any other drug known to enhance CP metabolism. The administration of CP less than 24 h after the last dose of Bu resulted in: (1) a significantly (P = 0.003) lower clearance for cyclophosphamide was observed in group A (0.036 l/h/kg) compared to 0.055 and 0.055 l/h/kg, in the B and TBI groups, respectively; (2) significantly (P = 0.002) longer elimination half-life in group A (10.93 h) than in groups B and TBI (6.87 and 7.52 h, respectively); (3) significantly (P < 0.001) lower exposure to the cytotoxic metabolite (4-OHCP), expressed as the ratio AUC4-OHCP/AUCCP, in group A (0.0053) than that obtained in group B (0.013) and group TBI (0.012); (4) the patients in group A had a significantly (P < 0.05) higher incidence of VOD (seven of 12) than the other groups, B and TBI (2/14 and 1/10, respectively); and (5) mucositis was significantly higher in group A patients (8/12), being seen in only one patient in group B and none in the TBI group. The present study has shown that the interval between busulphan and cyclophosphamide administration can negatively affect the pharmacokinetics of cyclophosphamide and its cytotoxic metabolite. We conclude that the timing of CP administration must be considered in order to improve drug efficacy and reduce conditioning-related toxicity.

Adolescent↗
PubMed2000

Plasminogen activator activity in tears after excimer laser photorefractive keratectomy.

PURPOSE: To quantify changes of plasminogen activator activity in tear fluid during corneal re-epithelialization after excimer laser photorefractive keratectomy (PRK). METHODS: Tear samples were collected with glass capillaries from 77 eyes of 42 patients immediately before and immediately after PRK treatment and on postoperative days 3 and 5. In 20 patients, the contralateral eye was similarly sampled to serve as control. Plasminogen activator activity in the tear samples was measured by a spectrophotometric method using human plasminogen and chromogenic peptide substrate, D-valyl-L-leucyl-L-lysine-p-nitroanilide (S-2251). RESULTS: In tears of all eyes that underwent PRK, the plasminogen activator activities were lower immediately after PRK than were the preoperative values. For patient eyes with normal wound healing, tear plasminogen activator activities were significantly elevated above the preoperative level on the third postoperative day and then returned to the preoperative level by the fifth postoperative day. In contrast, tear plasminogen activator activities remained low through the third postoperative day in all (six) eyes in which haze developed after 3 to 6 months. The contralateral control eyes showed no appreciable change in plasminogen activator activity over the 5-day period. CONCLUSIONS: Plasminogen activator activity levels measured in tears of excimer laser PRK-treated eyes may serve as a predictor of wound healing. Extended low levels of plasminogen activator activity through the third postoperative day correlate with the development of corneal healing abnormalities (haze). The low plasminogen activator activity could be not only an accompanying sign but also a cause of defective corneal wound healing.

Adolescent↗
PubMed1999

Effects of dry cow intramammary therapy on quarter infections in the dry period.

Quarter milk samples were taken from 150 cows from three dairy farms in south-east Queensland at drying off, two, four and six weeks after drying off, at calving, and one, two and three weeks after calving. In each of the herds, the cows were randomly allocated to three groups of approximately equal size. One group had all the quarters of all the cows treated at drying off with a dry cow antibiotic infusion containing cloxacillin; the second group was given no treatment, and the third group had selected quarters treated on the basis of their high activity of N-acetyl-beta-D-glucosaminidase at drying off. Dry cow treatment resulted in a marked reduction in the number of infected quarters at two and four weeks after drying off, so that the comprehensively treated group had significantly less infected quarters at these times (P<0.02). Twelve dinical cases of mastitis were detected two weeks after drying off in the untreated groups, 10 in the untreated quarters of the selectively treated groups, and no cases in the comprehensively treated groups. These cases were due mainly to Streptococcus uberis and Streptococcus dysgalactiae. The number of infected untreated quarters increased markedly between drying off and two weeks later, but in all three groups there was a marked decrease in the number of infected quarters between six weeks after drying off and calving, suggesting that the mammary glands were more able to overcome infections at this time.

Acetylglucosaminidase↗
PubMed1999

Two pathways of apoptosis induced with all-trans retinoic acid and etoposide in the myeloid cell line P39.

P39/Tsugane is a myelomonocytoid cell line derived from a patient with myelodysplastic syndrome (MDS). The cells readily undergo apoptosis in response to various agents, and the cell line has been suggested as a useful model to study apoptosis in MDS. The aims of the present study were to assess differentiation and apoptosis induced with all-trans retinoic acid (ATRA) and etoposide, to characterize the mode of apoptosis in these two model systems, and to assess the influence of granulocyte colony-stimulating factor (G-CSF), which in combination with erythropoietin has been shown to inhibit apoptosis in MDS. ATRA induced differentiation and apoptosis in a concentration- and time-dependent manner. Differentiated cells were partially rescued (by 50%) from apoptosis with G-CSF. Etoposide induced apoptosis in a concentration- and time-dependent manner, but no signs of preceding maturation or G-CSF rescue were detected. ATRA- and etoposide-induced apoptosis were both mediated through the caspase pathway and were partially blocked with the general caspase inhibitor zVAD-fmk. Simultaneous treatment with G-CSF and zVAD-fmk additively blocked ATRA-induced apoptosis. However, the two pathways differed in terms of substrate cleavage during apoptosis. ATRA-induced apoptosis caused actin cleavage, which was not affected by G-CSF, and Bcl-2 downregulation. Etoposide induced a caspase-dependent cleavage of Bcl-2, while actin remained intact. The Fas system did not seem to play a major role in any of these apoptotic pathways. Our results may provide new tools to study the mechanisms of apoptosis in MDS.

Actins↗
PubMed1999

Cleavage of Bcl-2 is an early event in chemotherapy-induced apoptosis of human myeloid leukemia cells.

The proto-oncogene product Bcl-2 protects a wide variety of cell types from apoptosis via a hitherto unknown mechanism. Bcl-2 has been shown to function upstream of the death proteases (caspases) in some, but not all, occurrences of apoptotic cell death. Using the myeloid leukemic cell line P39 we report the chemotherapy-induced caspase-dependent cleavage of endogenous Bcl-2. Etoposide treatment of these cells triggered a time-dependent activation of type II and type III caspases and cleavage of Bcl-2 yielding a 23 kDa cleavage fragment. The emergence of this cleavage product was blocked by the general caspase inhibitor zVAD-fmk, as well as the type III caspase inhibitor IETD-fmk and the caspase-9-selective inhibitor LEHD-fmk, while the type II caspase inhibitor DEVD-fmk proved considerably less efficient. Bcl-2 cleavage preceded cleavage of the known caspase-3 substrate, poly(ADP-ribose) polymerase (PARP), as well as that of the caspase-6 substrate, lamin B, indicating that Bcl-2 cleavage is a relatively early event in the apoptosis cascade in this experimental model. While evidence for cleavage of Bcl-2 in several subcellular compartments of etoposide-treated cells was obtained, this cleavage was detected predominantly in the mitochondrial fraction, thus providing further support for the central role of mitochondria in apoptosis. Caspase-mediated cleavage following etoposide treatment of these myeloid leukemic cells may represent a means for the attenuation of Bcl-2 function upon apoptosis induction.

Antineoplastic Agents, Phytogenic↗
PubMed1999

Serum and urinary magnesium in young diabetic subjects in Bangladesh.

BACKGROUND: Magnesium imbalance, implicated in diabetes mellitus both as a cause and a consequence, has not yet been investigated in subgroups of subjects with malnutrition-related diabetes mellitus. which is prevalent in young patients in tropical developing countries such as Bangladesh. OBJECTIVE: The present study evaluated the serum and urinary magnesium concentrations in groups of young diabetic subjects in Bangladesh. DESIGN: Forty patients newly diagnosed with diabetes [13 with fibrocalculus pancreatic diabetes (FCPD), 13 with protein-deficient diabetes (PDDM), and 14 with type 2 diabetes mellitus] were studied along with 13 healthy control and 13 malnourished control subjects [body mass index (in kg/m2) < 19]. Magnesium was measured by atomic absorption spectrophotometry. RESULTS: Malnutrition itself was not related to the serum glucose (fasting: 3.68+/-0.74 and 4.11+/-0.29 mmol/L; postprandial: 6.30+/-0.41 and 6.00+/-0.24 mmol/L for healthy and malnourished control subjects, respectively) or serum or urinary magnesium (serum: 0.73+/-0.03 and 0.75+/-0.05 mmol/L: urinary: 232+/-124 and 243+/-88 mmol Mg/mol creatinine for healthy and malnourished control subjects, respectively) concentration. Subjects with FCPD and PDDM had significantly lower serum magnesium concentrations (PDDM: 0.68+/-0.06 mmol/L, FCPD: 0.66+/-0.07 mmol/L) than those in both control groups. In contrast with 0% of healthy and 7.7% of malnourished control subjects, 42.85% of type 2 diabetic subjects, 61.54% of those with PDDM, and 69.23% of those with FCPD were hypomagnesemic. Subjects with FCPD and PDDM had significantly higher urinary excretion of magnesium than the healthy and malnourished control subjects and the type 2 diabetic subjects. Hypermagnesuria paralleled hypomagnesemia. CONCLUSIONS: Malnutrition may not itself give rise to glucose intolerance, and serum magnesium deficiency seems to be a consequence rather than a cause of diabetes mellitus.

Adolescent↗
PubMed1999

Hepatocellular carcinoma in Egyptians with and without a history of hepatitis B virus infection: association with hepatitis C virus (HCV) infection but not with (HCV) RNA level.

The aim of this study was to analyze the association of hepatocellular carcinoma (HCC) with hepatitis C virus (HCV) in Egypt, using hepatitis B virus (HBV) and hepatitis E virus (HEV) as virus controls. In addition, the association of HCC with HCV RNA levels among persons seropositive for HCV was analyzed. We compared 131 patients with proven HCC, 247 with bladder cancer, and 466 healthy hospital employees. Age, sex, and place of residence were recorded to study confounding factors. Among the healthy controls, 16% were seropositive for HCV, 21% for HBV, and 31% for HEV. When healthy controls were age-matched with HCC patients, the latter were significantly (P < 0.001) more often HCV seropositive (67%) than were the controls (30%). The seropositivity for HBV and HEV did not differ significantly in frequency between the two groups. The seropositivity for HCV was also significantly (P < 0.001) more often found in HCC patients (76%) than in BC patients (47%), with seroprevalences for HBV and HEV not differing significantly in these age-matched groups. In HBV-negative HCC and bladder cancer patients, seroprevalence for HCV was significantly (P = 0.002) higher in HCC patients (68%) than in bladder cancer patients (36%). This difference was even more pronounced (P < 0.001) in HBV-positive HCC and bladder cancer patients (78% versus 52%, respectively). Of HCV-seropositive individuals, 49% were HCV RNA positive by branched DNA assay, and of these, 96% were infected by HCV genotype 4. No correlation between HCV RNA load and seropositivity of HBV or age or disease state was found. Infection with HCV and HCV-HBV double infection, but not HBV or HEV infection alone, is strongly correlated with HCC in Egypt.

Adolescent↗
PubMed1998

Characterization of Vibrio vulnificus isolated from cockles (Anadara granosa): antimicrobial resistance, plasmid profiles and random amplification of polymorphic DNA analysis.

Antibiotic susceptibility, plasmid profiles and random amplification of polymorphic DNA (RAPD) were used to study strains of Vibrio vulnificus isolated from cockles (Anadara granosa). Thirty-six isolates were analyzed. The prevalent biotypes were 1 (72.2% of the isolates) and 2 (27.8%). Among these, 21 strains of biotype 1 and two strains of biotype 2 contained plasmid DNA bands ranging in size from 1.4 to 9.7 MDa. Thirty-one (83.3%) were found to be resistant to one or more of the antimicrobial agents tested, however no specific correlation between antimicrobial resistance patterns and a single biotype was found. In addition, no particular plasmid profile was predictive of a particular pattern of antibiotic susceptibility. Two primers produced polymorphisms in all strains tested, producing bands ranging from 0.25 to 2.7 kb, indicating a high variability among both biotype 1 and biotype 2 of the V. vulnificus strains investigated. RAPD identity across biotypes was also observed among Vibrio vulnificus strains.

Animals↗
PubMed1998

Pharmacokinetics and distribution of liposomal busulfan in the rat: a new formulation for intravenous administration.

The plasma pharmacokinetics and tissue distribution of busulfan (Bu) were investigated after intravenous injection of free Bu (D-Bu) and freshly prepared liposomal Bu (L-Bu). Liposomal Bu was prepared using L-alpha-phosphatidylcholine, 1,2-dioleolyl-sn-glycero-3-phosphate, and cholesterol. The liposomes formed were unilamellar vesicles measuring 220 +/- 14 nm in diameter and containing a Bu concentration of 0.31 +/- 0.03 mg/ml. The half-life of Bu in the present formulation was determined to be 8.7 +/- 2.7 days at 4 degrees C. The liposomes in the new formulation were stable for 20 days at 4 degrees C. After the intravenous administration of L-Bu or D-Bu (dissolved in a mixture of DMSO, ethanol, and propylene glycol) to the rats a higher bone marrow exposure to Bu as expressed in AUC marrow/AUC blood was achieved using L-Bu as compared with D-Bu (1.59 and 0.83, respectively). A higher distribution volume was observed for L-Bu as compared with D-Bu (1.39 versus 0.67 l/kg, respectively). The elimination half-lives were significantly longer in both blood and marrow after the administration of L-Bu as compared with D-Bu (2.52 and 3.08 versus 1.53 and 1.75 h, respectively). The new liposomal Bu showed linear pharmacokinetics within the range of 0.5-3.5 mg/kg, which is comparable with that obtained for D-Bu. A slight difference was observed in systemic exposure to L-Bu as compared with D-Bu as expressed in AUC (9.93 and 11.82 microg h ml(-1), respectively). The distribution study using 14C-labeled Bu showed that the radioactivity was significantly higher over 18 h in the bone marrow (3-fold) and spleen (2-fold; P < 0.01) in a comparison of L-Bu with D-Bu. However in the brain, lungs, and heart the distribution of radioactivity after the administration of L-Bu was significantly lower (P < 0.05) than that obtained using D-Bu. On the basis of the present study, the new formulation of liposomal Bu seems to be a promising preparation for clinical trials, since it appears to target bone marrow and spleen with no accumulation in the liver or other organs known for Bu toxicity.

Animals↗
PubMed1998

Liposomal busulphan: bioavailability and effect on bone marrow in mice.

High-dose busulphan is an important component of many BMT conditioning regimens. High-dose busulphan therapy is associated with an increased risk of acute toxicity such as CNS toxicity and veno-occlusive disease (VOD). The toxicity was reported to correlate with a high AUC (area under the curve) during therapy. An intravenous form of busulphan would overcome the problems caused by inter-individual variability and bioavailability of busulphan and most probably minimize the problems with dose adjustment during therapy. The liposomal form of busulphan is an attractive alternative for intravenous administration of busulphan. In the present study, we compared the myeloablative effect of liposomal busulphan (LB) with that of the oral administration form and busulphan dissolved in organic solvent (Bus/DMSO) in mice. The pharmacokinetics of LB and Bus/DMSO were described by one compartment model while the oral data were fitted to one compartment model with first order absorption. The bioavailability of LB was 0.86+/-0.02 compared to that obtained after the oral administration (0.40-0.74). Myelosuppression was determined using the colony-forming unit granulocyte-macrophage assay (CFU-GM) on days 1, 3, 6 and 9 after the conditioning regimen. LB resulted in significant myelosuppression from day 1 to day 9. The decrease in CFU-GM after conditioning regimen with LB was not significantly different from that observed after oral busulphan. Moreover, the administration of liposomes only to the mice did not affect the bone marrow. No side-effects of the liposomal formulation were observed. We suggest that the novel form of busulphan is a promising drug for clinical use.

Administration, Oral↗
PubMed1997

Excimer laser photorefractive keratectomy with different ablation zones.

In this study we would like to introduce the excimer laser, and to demonstrate our results and complications by using different ablation zones during photorefractive keratectomy (PRK) in the correction of myopia and astigmatismus. In 1996 we performed photorefractive keratectomy on 100 myopic eyes of 52 patients (28 females, 24 males). Mean age was 26.21 years (ranged from 19 to 54 years). The preoperative refraction ranged from -1.0 D to -18.0 Diopters. The diameter of the ablation zones were between 5 and 6.5 mm. We evaluated the results and the complications of the surgeries of 100 eyes which were performed with Schwind keratom F excimer laser. After 2 days, 1 week, 1 month, 3 months, and 6 months postoperatively we tested the best uncorrected and corrected visual acuities, and performed intraocular pressure measurement, slit lamp examination as well as corneal topography. The postoperative refractions were between +/- 0.5 to +/- 1.0 Diopters. After six months postoperatively the slit lamp examination showed that 80% of the patients had no corneal haze while 20% had stage I (Hanna) corneal haze. The smaller the diameter of the ablation zone was, the more pronounced the corneal haze and the night-glare were. The photorefractive excimer laser keratectomy is judged to be a safe method, although it might have some side-effects. The different ablation zones of this treatment means an important modification, that not only allows the method to meet the individual requirements, but reduces the chance of the complications as well. Based on the authors' experiences PRK for moderate myopia with large diameter ablation zones appears more predictable than than with smaller ablation zone diameters.

Adult↗
PubMed1995

Characterization of the hypoglycemic effects of Trigonella foenum graecum seed.

The whole powder of Trigonella foenum graecum seeds and its extracts were tested for their hypoglycemic effect on normal and diabetic model rats. The powder, its methanol extract, and the residue remaining after methanol extraction had significant hypoglycemic effects when fed simultaneously with glucose. The water extract of the methanol extractive-free residue of the seed powder showed significant hypoglycemic activity at different prandial states. The Soluble Dietary Fibre (SDF) fraction showed no effect on the fasting blood glucose levels of nondiabetic or NIDDM model rats. However, when fed simultaneously with glucose, it showed a significant hypoglycemic effect (p < 0.05) in NIDDM model rats. Chemical analysis showed that the major constituent of the SDF is a galactomannan. The results confirm the involvement of SDF in the hypoglycemic effect of T. foenum graecum seeds. However, compound(s) other than SDF is (are) also involved in the hypoglycemic activity.

Animals↗
PubMed1988

Intermamillary indices in premature infants.

The internipple distance and its relationship to gestational age has not been studied in infants born in the United States. One hundred and thirty-three newborns between 25 and 40 weeks gestation showed progressive increase in the internipple distance with increasing gestational age. The internipple index stays constant during various gestational ages. The internipple index greater than 28% (greater than 2 SD) at any gestational age or during immediate postnatal age should be flagged to look into widely spaced nipples. Extrauterine growth of internipple distance is similar to that of intrauterine growth.

Breast↗
PubMed1987

Clinical, hemodynamic, and angiographic predictors of operative mortality in patients undergoing single valve replacement. Veterans Administration Cooperative Study on Valvular Heart Disease.

Preoperative characteristics of 964 patients in the Veterans Administration Cooperative Study on Valvular Heart Disease undergoing single valve replacement were examined to determine predictors of operative mortality. The operative mortality rate was 8.3% in 661 patients having isolated aortic valve disease and 7.5% in 239 patients having isolated mitral valve disease, but 12.5% in 64 patients with multivalve disease undergoing single valve replacement. For the aortic valve replacement subgroup, three-vessel coronary artery disease, left ventricular systolic pressure, prior cardiac operation, body surface area, and cardiac index were related to operative mortality. In the mitral valve replacement group, there was a strong association of operative mortality with advanced age, exertional dizziness, reduced cardiac index, left ventricular contraction grade, ST segment depression on the resting electrocardiogram, and pleural effusion. The risk of operative death for an individual patient undergoing aortic or mitral valve replacement may be estimated with the use of independent risk factors.

Adult↗