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Biomedical subjects

M A Rashid

Publications and source records attributed to M A Rashid.

At least 73 records · Page 4Linked to original sources
PubMed1992

Coumarins from Phebalium tuberculosum ssp. megaphyllum and Phebalium filifolium.

A total of 14 coumarins have been isolated from the aerial parts of Phebalium tuberculosum ssp. megaphyllum and 9 from Phebalium filifolium (Rutaceae). Three of the coumarins obtained from P. tuberculosum ssp. megaphyllum are novel and have been characterized, on the basis of spectroscopic analysis, as (E)-7-(6-hydroperoxy-3,7-dimethylocta-2,7- dienyloxy)coumarin [3], (E)-8-(6-hydroperoxy-3,7-dimethylocta-2,7-dienyloxy)psoralen [16] and (E,E)-8-(7-hydroxy-3,7-dimethylocta-2,5-dienyloxy)psoralen [15] In addition, both species yielded the simple acetophenone xanthoxylin, and P. tuberculosum ssp. megaphyllum gave (E)-betulin-3-p-coumarate [20] and (Z)-betulin-3-p-coumarate [21], both of which appear to be novel. The chemotaxonomic implications of coumarin distribution in the two species are discussed.

Chromatography, Liquid↗
PubMed1991

Influence of allopurinol on cardiac complications in open heart operations.

During cardiac operations, the heart is subjected to total ischemia and reperfusion, causing serious operative and postoperative complications such as arrhythmias, heart failure, and infarctions that may be partly due to free radical generation. Thus, allopurinol was tested to see if it could reduce cardiac complications during open heart operations. Ninety patients undergoing elective coronary artery bypass grafting were studied prospectively. Fortyfive patients were treated with allopurinol and 45 patients acted as controls. Treatment requiring arrhythmias in the allopurinol group was 6.6% compared with 33.3% in the control group (p less than 0.01). The percentage of patients requiring inotropes was significantly lower in the allopurinol group than in the control group (4.4% versus 26.6%; p less than 0.01). Perioperative myocardial infarction did not occur in the allopurinol group but was seen in 8 patients (17.7%) in the control group. Intraaortic balloon pumping was used in 5 control patients (11.1%) but not in the allopurinol group. This study shows that allopurinol decreases significantly the incidence of cardiac complications in open heart operations.

Adult↗
PubMed1991

Selective association of a fragment of the knob protein with spectrin, actin and the red cell membrane.

The knob protein of Plasmodium falciparum is essential for the formation of knob-like protrusions on the host erythrocyte membrane. A functional domain of the knob protein was identified. This peptide formed stable complexes with the two major red cell skeletal proteins, spectrin and actin. When introduced into resealed normal erythrocytes, the peptide associated selectively with the cytoplasmic surface of the membrane and formed knob-like electron dense deposits. Knobs are thought to play an important role in the immunopathology of P. falciparum infections. Our findings provide a first step towards understanding the molecular basis for selective membrane changes at knobs.

Actins↗
PubMed1991

Are leukocytosis and lipid peroxidation involved in ischemic or reperfusion injury in cardiac surgery?

We have studied the hypothesis that free-radical generation during cardiac surgery could explain partly the pathophysiology of ischemic or reperfusion injury during cardiopulmonary bypass (CPB). Ten patients undergoing cardiac surgery using CPB were prospectively studied. Malondialdehyde (MDA) was measured as a marker of free-radical-induced lipid peroxidation (LPO) using the thiobarbituric acid method, and leukocytes were counted during ischemia and reperfusion. Both MDA and leukocytes increased significantly, especially after starting reperfusion. There was significant correlation between LPO and leukocytosis (r = 0.8, p less than 0.005). It is concluded that free radicals generated during ischemia and reperfusion lead to an increase of LPO, which is shown for the first time to be associated with leukocytosis in cardiac surgical patients. The implication of this observation is of importance for the treatment strategy using free-radical scavengers in reducing the harmful effects of ischemia and reperfusion in cardiac surgery.

Aged↗
PubMed1990

Expression, partial purification and immunogenicity of fragments of the knob protein of Plasmodium falciparum.

Three structural domains of the histidine-rich knob protein (KP) of Plasmodium falciparum were expressed in Escherichia coli. A single-step purification scheme was devised to obtain great enrichment of expressed polypeptides for use in subsequent experiments. Immune human sera from Africa, South-East Asia and South America were tested for reactivity with each of the expressed fragments. While the two fragments which represented the central and C-terminal regions of KP showed a strong reactivity with all the antisera which were tested, the N-terminal fragment which contains the repetitive histidine-rich sequences showed almost no reactivity.

Amino Acid Sequence↗
PubMed1983

Pernicious anaemia with subacute combined degeneration of cord in a Bangladeshi male.

Pernicious anaemia (PA) has previously not been reported from Bangladesh. A case is described which had the typical clinical features of PA with subacute combined degeneration of the cord and polyneuropathy. The patient had typical macroovalocytosis, megaloblastic bone marrow and Schilling test result in the range of PA. Vitamin B12 level in the serum was markedly reduced. There was rapid clinical and haematological response to vitamin B12 therapy.

Anemia, Pernicious↗
PubMed1970

Comparative study of the primary structures of cytochrome b5 from four species.

The primary structures of human, bovine, and chicken cytochrome b(5) have been determined and compared with that of the previously studied rabbit protein. One peptide containing 31 amino acid residues and another containing 10 were found common to all four species. The substitutions of amino acids between species could be accounted for mainly by single base exchange, with a few exceptional double base exchanges for the chicken. Results for bovine cytochrome b(5) differ significantly from those previously reported for calf cytochrome b(5).

Amino Acid Sequence↗