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Biomedical subjects

S Malik

Publications and source records attributed to S Malik.

At least 127 records · Page 7Linked to original sources
PubMed1992

Optic neuropathy: a rare paraneoplastic syndrome.

A 63-year-old man developed gradually progressive bilateral loss of vision, cerebellar ataxia, and downbeat nystagmus. Visual acuity was 20/400 OD and 20/200 OS, with cecocentral scotomas OU. Fundus examination showed bilateral optic atrophy and a vitreous cellular reaction. MRI of the brain was normal. CSF protein was elevated, with increased IgG levels but no malignant cells. Biopsy of a pulmonary lymph node showed undifferentiated small cell carcinoma. Neoplastic cells were positive for neuron-specific enolase. Serum contained IgG, which reacted with neuronal and glial cytoplasm and processes. IgG reactivity with systemic tissues and the patient's tumor was not different from that observed with control sera. Paraneoplastic optic neuropathy should be considered in patients with unexplained visual loss and malignancy, and our observations suggest a possible immunologic basis for this condition.

Antineoplastic Agents↗
PubMed1992

Comparative study of oral versus injectable vitamin K in neonates.

One hundred term exclusively breast fed babies weighing more than 2.5 kg were evaluated to determine the efficacy of various modes and doses of Vitamin K to prevent hemorrhagic disease of newborn (HDN). The babies were grouped into four categories of 25 each: Group A--1 mg Vitamin K intramuscular (Menadione sodium disulphite) at birth; Group B--0.5 mg Vitamin K intramuscular; Group C--1 mg Vitamin K orally, and group D--no Vitamin K. The prothrombin index was estimated in all babies between 36-72 hours of age. The results revealed a prothrombin index in Groups A, B, C and D as 94.98 +/- 7.64%, 95.08 +/- 9.91%, 92.51 +/- 10.10% and 80.39 +/- 15.90%, respectively. The differences between Groups A, B and C were insignificant. However, Group D, prothrombin index was significantly reduced as compared with the other three groups. It is, therefore, concluded that oral Vitamin K is as effective as injectable Vitamin K and its usage is recommended in our country to reduce complications and costs of parenteral therapy.

Administration, Oral↗
PubMed1992

Experience with screening for abnormal glucose tolerance in pregnancy: maternal and perinatal outcome.

In order to determine the prevalence of glucose intolerance in pregnancy, 2,230 consecutive women attending the antenatal clinic at the Aga Khan University Medical Centre in Karachi, Pakistan were subjected on the first antenatal visit, irrespective of gestational age, to a 75 g glucose challenge followed 2 hr later by plasma glucose determination. The test, was repeated at 28-32 weeks of gestation for those patients who had an abnormal initial screen at less than 28 weeks gestation followed by a normal glucose tolerance test and for those who had a risk factor for gestational diabetes even though the initial screen at less than 28 weeks gestation was normal. The initial glucose challenge test was abnormal (2 hr plasma glucose greater than 140 mg%) in 8.6% of the screened population. An oral glucose tolerance test on these patients revealed a prevalence for the entire population of 3.5% of gestational diabetes and 1.9% of impaired glucose tolerance test based on the modified O'Sullivan criteria. Patients with abnormal glucose tolerance test were older, had higher parity, a past history of macrosomia and a family history of diabetes compared to the controls. These patients also had a higher incidence of preterm labour and caesarean section. In the neonates hypoglycemia and hyperbilirubinemia were similarly higher. The fetal abnormality rate was 5.6% and the perinatal mortality was 28/1,000 which were higher than the controls.

Birth Weight↗
PubMed1991

Sequence of general transcription factor TFIIB and relationships to other initiation factors.

Transcription factor TFIIB is a ubiquitous factor required for transcription initiation by RNA polymerase II. Previous studies have suggested that TFIIB serves as a bridge between the "TATA"-binding factor (TFIID) and RNA polymerase II during preinitiation complex assembly and, more recently, that TFIIB can be a target of acidic activators. We have purified TFIIB to homogeneity, shown that activity resides in a 33-kDa polypeptide, and obtained cDNAs encoding functional TFIIB. TFIIB contains a region with amino acid sequence similarity to a highly conserved region of prokaryotic sigma factors. This is consistent with analogous functions for these factors in promoter recognition by RNA polymerases and with similar findings for TFIID, TFIIE, and TFIIF/RAP30. Like TFIID, TFIIB contains both a large imperfect repeat that could contribute an element of symmetry to the folded protein and clusters of basic residues that could interact with acidic activator domains. These findings argue for a common origin of TFIIB, TFIID, and other general transcription factors and for the evolutionary segregation of complementary functions.

Amino Acid Sequence↗
PubMed1991

Desferal-Mn(III) in the therapy of diquat-induced cataract in rabbit.

In rabbit lenses subjected to oxidative stress, induced by 1 mM diquat in vitro, there were 7- to 10-fold increases (p less than 0.001) in malondialdehyde, conjugated dienes, and carbonyl dienes, indicating extensive peroxidation of cellular membrane lipids, and approximately a 60% decrease in reduced glutathione. In the presence of 0.1-5 mM Desferal-Mn(III) these changes were diminished by 50-70%. In an experimental group of 12 rabbits having diquat-induced cataract, Desferal-Mn(III) (5% w/v) applied topically as a 50-microliters eye drop four times per day and a single intraperitoneal dose of 64 mg/kg body wt daily for 5 weeks (including pretreatment for 1 week) retarded the progression of lens opacities, whereas, in a control group of 6 rabbits treated with the vehicle (0.15 M NaCl) cataract progressed to an advanced grade. Treatment with Desferal-Mn(III) also significantly diminished production of O2.- and OH. in the lens, aqueous humor, and vitreous humor, and of H2O2 in the aqueous humor and vitreous humor. It also suppressed lipid peroxidation and oxidation of protein-SH of the lens and restored lenticular glutathione and ascorbate to normal levels.

Animals↗
PubMed1991

Maternal and perinatal complications in neurofibromatosis during pregnancy.

A total of ten patients with lesions of neurofibromatosis during pregnancy were followed up for pregnancy complications. Seven cases (70%) had hypertensive disorders of pregnancy; four had severe PET (pre-eclamptic toxemia) including one case of eclampsia, one had mild PET and the other two had only mild gestational hypertension. A total of 60% had preterm labor and in none of these did the baby survive; thus perinatal mortality was 600/1000. Mean gestation was 33.0 weeks and mean birthweight was only 1.924 kg. Thus, neurofibromatosis during pregnancy is associated with poor obstetrical outcome and requires greater care.

Adult↗
PubMed1991

The use of intravenous immunoglobulin (IVIG) to prevent infections in bronchopulmonary dysplasia: report of a pilot study.

The incidence and severity of pneumonia, sepsis, and other infections was evaluated in a group of 30 premature infants with moderate to severe bronchopulmonary dysplasia (BPD), half of whom were randomly treated with intravenous immunoglobulins (group A). The patients were treated until the age of 6 months. They were compared with an untreated control group (group B). The number of pneumonic episodes (5 in group A and 15 in group B) and other infections, excluding sepsis (1 in group A and 7 in group B), were significantly reduced in the treated group (P less than .05). The number of episodes of sepsis, suspected sepsis, and necrotizing enterocolitis were similar in the two groups. The decrease in the number of respiratory and other infections in BPD infants treated with IVIG requires verification by a larger trial.

Bacterial Infections↗
PubMed1990

Intergeneric protoplast fusion between xylanase producing Bacillus subtilis LYT and Corynebacterium acetoacidophilum ATCC 21476.

Hybrids between a strain of Bacillus subtilis isolated in our laboratory and having the ability to degrade xylan and other complex polysaccharides and Corynebacterium acetoacidophilum, a lysine producer, were prepared by protoplast fusion. Based on distinctive parental biochemical characteristics the fusants were grouped into 9 categories, viz. BC1 through BC9. Three of the hybrids, BC5, BC7a and BC7b, were tested for their ability to produce xylanase and lysine. Both BC7a and BC7b produced xylanase but BC5 did not, however all of them produced lysine albeit to different degrees. These results demonstrate that intergeneric gene transfer takes place through protoplast fusion between these 2 important genera of bacteria and some of the fusants inherit the useful traits of both the parents.

Bacillus subtilis↗
PubMed1990

Infusion of tumor necrosis factor (TNF) causes an increase in circulating TNF-binding protein in humans.

Serum samples from cancer patients receiving intravenous infusions of recombinant tumor necrosis factor (rTNF) and recombinant interferon-gamma (rIFN-gamma) were analyzed for TNF and the TNF-binding protein (TNF-BP). TNF-BP is a soluble fragment of the transmembrane TNF receptor with antagonistic effects to TNF and is released by proteolytic cleavage of the receptor. During a 60-min infusion of rTNF, peak serum levels of rTNF were observed after 30 to 60 min and a transient increase of circulating TNF-BP was observed with peak levels between 30 and 120 min. Injection of IFN-gamma alone did not affect the levels of TNF and TNF-BP. Thus administration of rTNF leads to release into the circulation of TNF-BP, which may modulate both systemic and local effects of TNF and influence its therapeutic efficacy.

Carrier Proteins↗
PubMed1989

A randomized trial to evaluate the effect of schedule on the activity of etoposide in small-cell lung cancer.

Etoposide is an increasingly used and well-tolerated drug in cancer medicine. Its cytotoxic action is phase-specific and it has demonstrated schedule dependency in both in vitro and animal studies, but clinical evidence of the importance of drug scheduling is uncertain. The two administration schedules of etoposide that have been compared in this randomized study of 39 patients with previously untreated extensive small-cell lung cancer treated with single-agent etoposide were 500 mg/m2 as a continuous intravenous (IV) infusion over 24 hours or five consecutive daily 2-hour infusions each of 100 mg/m2. Both regimens were repeated every 3 weeks, for a maximum of six cycles. Patients received combination chemotherapy with vincristine, doxorubicin, and cyclophosphamide (VAC) or radiotherapy on failure to respond or at relapse, depending on their Karnofsky performance status. The same therapy was used in both arms of the study. All patients are evaluable for response to etoposide. In the 24-hour arm, two patients achieved a partial remission, resulting in an overall response rate of 10%. In the 5-day schedule, 16 patients had a partial response and one had a complete remission, producing an overall response rate of 89%, which was significantly superior to that in the 24-hour arm (P less than .001). The median duration of remission to etoposide in the 5-day arm was 4.5 months. Bone marrow toxicity was similar in both schedules. Etoposide pharmacokinetics were measured in all patients, and total areas under the concentration versus time curves (AUCs) were equivalent in both regimens. This study has clearly demonstrated the importance of etoposide scheduling in humans, and the superiority of five daily infusions over a 24-hour continuous infusion. The response rate to single-agent etoposide using an efficacious schedule in extensive small-cell lung cancer has been determined to be in excess of 80%.

Antineoplastic Combined Chemotherapy Protocols↗