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Biomedical subjects

N R Khan

Publications and source records attributed to N R Khan.

12 recordsLinked to original sources
PubMed1996

HBsAg ELISA: comparison of serum and uncentrifuged plasma samples dried on filter paper.

To compare the serum and uncentrifuged plasma for hepatitis B surface antigen (HBsAg) enzyme linked immuno sorbent assay (ELISA), ninety samples were analysed. The study was conducted so that in the field, where no amenities are available especially in countries like Pakistan, the separated but uncentrifuged plasma may be preserved by spotting on the filter paper for sero-epidemiological studies later. It was found that there was no statistically significant difference between the serum and uncentrifuged plasma values.

Centrifugation↗
PubMed1983

Erythroid burst formation in cultures of bone marrow and peripheral blood from patients with refractory anemia.

We have studied the growth of erythroid bursts in methylcellulose cultures from bone marrow (7 cases) and peripheral blood cells (17 cases) of patients with primary acquired refractory anemias. In most cases, erythroid burst-forming units (BFU-E) were either absent or present in lower than normal numbers, and these levels remained low to absent in sequential studies. In 2 patients, circulating BFU-E were initially higher than normal, but subsequently declined to normal levels. 1 patient had low-normal numbers of circulating BFU-E initially, but these declined to zero in a later study. No clinical or routine hematological features permitted distinction between patients with initially high BFU-E and those with initially low or absent BFU-E. These findings parallel those reported for granulocyte-macrophage progenitors in refractory anemias, and support the concept that erythroid progenitor cells in these disorders are influenced by the disordered hematopoiesis.

Adult↗
PubMed1979

A rapid technique for measuring calcium uptake in mitogen-induced T and B lymphocytes.

The procedures for lymphocyte activation and for removing the cells from the radioactive loading solution in incubation medium were modified to routinely obtain significant and reproducible 45Ca2+ uptakes in mitogen-induced mouse T and B lymphocytes. Factors such as mouse strain, lymphocyte origin, and media pH were not critical to the 45Ca2+ uptake measurements. In contrast, factors such as lymphocyte cell concentration during mitogenic activation, filtering the 45Ca2+:3H2O mixtures, and the nature and purity of the B-cell mitogens were critical for obtaining maximal and reproducible 45Ca2+ uptakes. Centrifugation through silicone oil into sucrose was an efficient and rapid procedure for separating the cells from the radioactive loading solution in the incubation medium. Using optimal conditions, an approximate twofold increase in 45Ca2+ uptake (representing an influx of approximately 97 amol per lymphocyte and an increase in average cellular Ca2+ of approximately 0.72 mM) was routinely obtained with purified mouse lymphocytes activated with a variety of T- and B-cell mitogens (using concentrations resulting in maximal [3H]thymidine incorporation). A larger 45Ca2+ uptake was routinely obtained with mitogenic concentrations of A23187, a divalent cation ionophore stimulating T cells. Experiments employing [14C]sucrose and [14C]inulin with control and mitogen-induced lymphocytes showed that the trapped extracellular fluid measurements in the cell pellets should be used to correct the magnitude of the 45Ca2+ uptake measurements.

Animals↗
PubMed1978

The PO protein. The major glycoprotein of peripheral nerve myelin.

A glycoprotein, referred to as PO protein, was isolated from rabbit sciatic nerve myelin by gel filtration on Agarose 0.5 m in dodecyl sulfate. The purified myelin was first defatted and extracted at pH 2. The water-soluble proteins such as myelin basic protein and P2 protein were extracted leaving a glycoprotein-rich residue, from which the PO protein was isolated. The purified protein showed a single band on gel electrophoresis in dodecyl sulfate when stained with Coomassie Blue of periodic acid-Schiff reagent. The carbohydrate, comprising 6.3% by weight, appears to exist as a nonasaccharide unit having 3 mannose, 3 N-acetylglucosamine, 1 sialic acid, 1 galactose and 1 fucose residue. The polypeptide moiety has a high content of non-polar amino acids. A single amino acid, isoleucine, was found at the NH2-terminal end by dansyl and Edman procedures. The PO protein is the major protein of peripheral nerve myelin.

Amino Acids↗
PubMedDate not supplied

Outpatient transesophageal echocardiography with intravenous propofol anesthesia in children and adolescents.

Outpatient transesophageal echocardiography (TEE) was performed in 10 children and adolescents (aged 3 to 19.5 years, mean 13.5 years; weight 12 to 91 kg, mean 49 kg), including two with Down's syndrome and one with autism, for diagnostic evaluation of issues unresolved by transthoracic echo examination (TTE). Issues for TEE: evaluation for atrial septal defect (two patients); anatomy of left ventricular outflow tract obstruction (one patient); aortic valve anatomy before valvuloplasty for insufficiency (one patient); evaluation for cause of cyanosis after Fontan operation (one patient); determination of source of high-velocity intracardiac turbulence after atrioventricular septal defect repair (one patient); rule out cardiac embolic source in patient with stroke (one patient); evaluate prosthetic valve function and rule out thrombus (one patient); determination of anatomic relationship of mitral valve to a ventricular septal defect before surgery for complex cyanotic heart disease (one patient); and evaluation for aortic dissection in Marfan's syndrome (one patient). Intravenous propofol anesthesia administered without endotracheal intubation by an anesthesiologist allowed successful outpatient TEE in nine patients; midazolam-conscious sedation was used in one. Outpatient TEE resolved diagnostic issues in all patients without complication, thereby avoiding cardiac catheterization in six patients and supplementing catheterization for preoperative planning in four patients. TEE can be performed safely and effectively with propofol anesthesia in the outpatient setting in carefully selected children and adolescents to provide vital diagnostic information. However, given the invasive nature of the procedure and the use of anesthesia, outpatient pediatric TEE should be used judiciously.

Adolescent↗