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Biomedical subjects

S Kaplan

Publications and source records attributed to S Kaplan.

At least 307 records · Page 17Linked to original sources
PubMed1985

Phospholipid transfer proteins in microorganisms.

Phospholipid transfer activity has been demonstrated in cell lysates of Saccharomyces cerevisiae, Rhodopseudomonas sphaeroides and Bacillus subtilis, and proteins facilitating phospholipid transfer from the first two organisms have recently been purified. The phospholipid transfer protein from S. cerevisiae has mol. wt. 35 000 with a specificity of transfer for phosphatidylinositol and phosphatidylcholine. The purified phospholipid transfer protein from R. sphaeroides has mol. wt. 27 000 and, although it has the ability to transfer all phospholipid species tested it displays a preference for phosphatidylglycerol. The cellular levels of phospholipid transfer activity in both S. cerevisiae and R. sphaeroides are not strictly related to the level of subcellular membranes. However, in photosynthetically grown R. sphaeroides, the distribution of the activities between soluble and membrane-associated forms is correlated with the level of intracytoplasmic membrane (a postulated membrane substrate).

Bacillus subtilis↗
PubMed1985

Topology and neighbor analysis of the photosynthetic reaction center from Rhodopseudomonas sphaeroides.

The subunit arrangement of the reaction center complex (RC) of Rhodopseudomonas sphaeroides was studied by chemical modification with four different cross-linking reagents using purified RC in lauryldimethylamine oxide, RC incorporated into liposomes, and intact chromatophore membranes, from which RCs are isolated. The RC of R. sphaeroides is composed of three polypeptide subunits, H, M, and L, apparent molecular mass as determined in sodium dodecyl sulfate-polyacrylamide gel electrophoresis, of 28,000, 24,000, and 21,000, respectively. The intra-complex products produced, were found to contain the polypeptides H-M-L, H-M, H-L, and M-L linked together. In addition, the cross-linking of cytochrome c to solubilized and membrane-bound RCs was observed with all four reagents. The products were found to be only a cytochrome c linked to either the M or L polypeptide. These results indicate that a portion of the L and M subunits of the RC must be exposed in situ on the periplasmic surface of the membrane near a binding site for cytochrome c on the RC, and all three subunits must be in close proximity to one another.

Chlorophyll↗
PubMed1985

[Effect of interferon-alpha 2 (E. coli) in hairy cell leukemia].

Recombinant interferon-alpha 2 (E. coli) produced a clinically significant improvement in hemoglobin, granulocytes and platelets in 7 of 8 patients with hairy cell leukemia. Response to treatment was already noticeable in the fourth treatment week. In one case without improvement after 120 days, treatment was stopped. So far only one complete remission has been documented. Because of the remarkable improvement in the peripheral blood values, the induction of a complete remission may not be the ultimate goal of interferon treatment. The side effects of this subcutaneous low-dose treatment consisted mainly of mild flu-like symptoms of short duration. The results obtained with recombinant interferon-alpha 2 confirm the initial observation by Quesada et al. with partially purified leukocyte-interferon. In our experience, these results are superior to those obtained in similar conditions with chlorambucil.

Adult↗
PubMed1985

Noninvasive evaluation of newborns with suspected congenital heart disease.

In the distressed newborn, the presence or absence of congenital heart disease (CHD) may be difficult to determine on clinical grounds alone. We prospectively studied 104 infants who were younger than 7 days of age and in whom CHD was suspected. The presence of CHD was detected noninvasively in 64 infants. The other 40 infants were considered not to have CHD. None of these 40 infants underwent cardiac catheterization for the purpose of excluding CHD, although three (7.5%) were subsequently found to have incidental cardiac lesions. In nine (14%) of the patients with CHD, the noninvasive diagnosis was incomplete. In four patients, ventricular septal defects were not detected; in another patient, a suspected ventricular septal defect was not confirmed at catheterization. In addition, three abnormalities of the great vessels were misdiagnosed noninvasively. We conclude that cardiac catheterization is not necessary to exclude significant CHD in the distressed newborn resulting from noncardiac causes, but significant diagnostic errors regarding anomalies of the aortic arch and ventricular septal defects may occur, based on the noninvasive evaluation alone.

Cardiac Catheterization↗
PubMed1985

Lack of correlation between blood gold concentrations and clinical response in patients with definite or classic rheumatoid arthritis receiving auranofin or gold sodium thiomalate.

We investigated the correlation between whole blood gold concentrations and clinical outcomes in 59 auranofin-treated patients and 51 gold sodium thiomalate-treated patients who completed a 21-week, placebo-controlled, multicenter parallel trial. Whole blood gold concentrations did not correlate with clinical outcome, as assessed by changes in joint tenderness, joint swelling, or Westergren erythrocyte sedimentation rate. They also did not correlate with toxic reactions necessitating withdrawal from the study.

Adolescent↗
PubMed1985

Gold: hepatotoxic and cholestatic reactions.

Gold hepatotoxicity is an uncommon but significant clinical problem. Hepatitis was first manifested one day to four weeks after the last dose of gold at a cumulative range of 35 to 2900 mg. An interesting dichotomy was noted between cholestatic and hepatotoxic reactions. Hepatotoxic reactions were associated with other clinical signs of hypersensitivity, thus facilitating differential diagnosis from viral hepatitis. Sudden clinical improvement in a patient receiving gold should stimulate evaluation for a hepatotoxic reaction.

Adult↗
PubMed1985

Hemodynamically significant PDA: an echocardiographic and clinical assessment of incidence, natural history, and outcome in very low birth weight infants maintained in negative fluid balance.

Fifty very low birth weight (VLBW) infants (750-1500 g, 27-33 weeks gestational age) were assigned at random to one of two groups of negative fluid balance and underwent prospective clinical and echocardiographic examinations during the first month of life. The purpose was to determine: the effect of fluid restriction on the incidence of ductal shunting, the reliability of the physical examination in diagnosing significant ductal shunting, and the relationship between significant ductal shunting and outcome in such infants. None of the infants had manipulations to close the ductus during the first week of life. Using routine structural and functional echocardiographic indices as criteria for the diagnosis of hemodynamically significant ductal shunting (hsPDA), we found that the two fluid-balance groups (8%-10% weight loss vs 13%-15% weight loss) did not significantly differ in incidence of hsPDA, duration of ventilation, or development of BPD. These two groups were then combined for further analysis: 32 (64%) of 50 VLBW infants had hsPDA during the first week of life. The group of infants with hsPDA did not differ significantly from that without hsPDA in birth weight or gestational age, but had a significantly lower Apgar score (P less than 0.04) and was significantly more likely to require ventilator support for RDS (P less than 0.01). Although when present a typical ductal murmur was specific for the development of significant ductal shunting, no murmur was heard in 21 (66%) of 32 infants with early hsPDA.(ABSTRACT TRUNCATED AT 250 WORDS)

Body Weight↗
PubMed1985

Spontaneous closure of isolated secundum atrial septal defects in infants: an echocardiographic study.

The incidence and timing of spontaneous closure of isolated secundum atrial septal defects are unknown. Twenty-nine consecutive infants under 12 months of age with clinical evidence of significant left-to-right shunting through atrial septal defects were evaluated by M-mode and two-dimensional echocardiography (2DE). All had right ventricular hypertrophy by ECG. Right ventricular, right atrial, and left atrial areas were measured and right ventricular and left atrial dimensions were obtained in all patients. Spontaneous closure of the defect in four infants was suggested by normalization of clinical examination and ECG and was documented by 2DE and M-mode echocardiography at 15 to 31 months of age. All of the remaining patients, who had suitable 2DE echocardiograms and who did not spontaneously close their defects, had enlarged right ventricular and right atrial areas. Left atrial areas were normal in the four who closed spontaneously and were large in all but three who did not close. The mean diameter of the defect was similar for all patients. The 14% incidence reported here may underestimate the true incidence of spontaneous closure, since seven patients had surgical closure, all prior to 30 months of age, the oldest age at which spontaneous closure was documented. An atrial septal flap, found in all four patients who closed spontaneously but only in 4 of the 16 patients who did not close spontaneously, may contribute in some way to spontaneous closure. Since spontaneous closure may occur up to 30 months, it seems clear that surgical closure should not be performed before that age unless medical management has failed to control symptoms.

Age Factors↗
PubMed1985

Long-term echocardiographic evaluation of cardiac size and function in patients with Kawasaki disease.

The long-term effects of Kawasaki disease on the cardiac function were evaluated in 67 patients. Serial M-mode echocardiograms were obtained at the time of the initial diagnosis, 1 to 3 months, at 3 to 12 months, and at greater than 12 months following the diagnosis. Left ventricular and left atrial dimensions, shortening fraction, left and right ventricular systolic time interval ratios, and computer analysis of digitized echoes of the left ventricular chamber and posterior wall were obtained. The left atrial and left ventricular dimensions were abnormal in half of the patients throughout the study periods. The shortening fraction was abnormal initially but became normal by the end of 3 months. The peak rates of emptying of the left ventricle and thickening of the posterior wall were significantly reduced in all evaluation periods. In addition, the peak rate of diastolic thinning of the posterior wall was reduced, although the peak rate of filling remained normal. Finally, more than 30% of patients studied beyond 12 months had a prolonged major filling and thinning period. There was no difference between patients with or without coronary artery aneurysms. All other systolic and diastolic phase intervals and rates of changes were normal. Contrary to previously published reports, we conclude that patients with Kawasaki disease who do not have demonstrable coronary artery disease, exhibit abnormalities of cardiac chamber size and function long after their acute illness.

Adolescent↗
PubMed1985

Characterization of light-harvesting mutants of Rhodopseudomonas sphaeroides. I. Measurement of the efficiency of energy transfer from light-harvesting complexes to the reaction center.

Light-harvesting mutants of Rhodopseudomonas sphaeroides lacking either the B800-850 complex or the B875 complex have been characterized by their absorption spectra in the visible and near-infrared region, and by their ability to transfer energy from the light-harvesting complexes to the reaction center. A new method of measuring the relative efficiency of energy transfer from the light-harvesting complexes to the reaction center is described. The B875- mutant had absorption maxima in the near-infrared at 800 and 849 nm with no evidence of an 875-nm shoulder. The efficiency of energy transfer from the light-harvesting complexes to the reaction center in the B875- mutant was 24% of the value measured for the wild-type strain and the B800-850- mutant. Yet, despite the fact that the efficiency of energy transfer for the B800-850- mutant and the wild-type strain were the same, there was a large difference in their photosynthetic unit size. These results are discussed in the context of a model in which light energy captured by the B800-850 complexes is transferred through the B875 complexes to the reaction center.

Bacterial Proteins↗
PubMed1985

Glutaraldehyde preparation of coronary artery bypass bioprostheses.

A method for glutaraldehyde (GA) fixation of canine carotid arteries has been developed for the preparation of small caliber biologic prostheses for coronary artery bypass. The biologic grafts were preserved by a static inflation technique that proved to be more advantageous than the standard stenting method. The most suitable static inflation pressure was found to be 120 mm Hg. By means of colorimetric measurements the minimal tanning time and the amount of GA required for complete fixation for canine vascular tissue were established. Stabilization of the vessel collagen and confirmation of GA-collagen cross-linking were verified by evaluation of the elastic properties and shrinkage temperature of the grafts. Stress-strain measurements were evaluated to determine the number of cross-links introduced in the vascular tissue by GA. This number was shown to be proportional to the inflation pressure. Ethyl alcohol was chosen as the storage solution because it maintained the best physical, chemical, and histologic characteristics of the grafts. Biological evaluations were performed with carotid implants that were examined following acute low flow studies and implantations up to 112 days. All implantations have yielded 100% patencies.

Aldehydes↗
PubMed1985

Phase I trial of 1,2,4-triglycidylurazol (TGU, NSC 332488): a new triepoxide cytostatic agent.

1,2,4-Triglycidylurazol, a new triepoxide derivative, was chosen for phase I trial because of its favorable water solubility, stability and antitumor activity in murine systems. Fifty-seven patients were evaluable. Hematologic toxicity was dose-limiting, with a steep dose-toxicity curve. At 650 mg/m2 2/10 patients developed grade II toxicity. Seventeen patients were treated at 800 mg/m2 and seven developed grade III or IV toxicity according to WHO. Five of these patients had received greater than 3 cytotoxic agents and/or extensive radiotherapy. One toxic death was seen. Cumulative toxicity was observed with respect to hematologic values in a comparison of the first and second courses. Sixteen patients developed phlebitis after injection, not dose-dependent and not dose-limiting. Response was noted in three patients, two non-small cell lung cancers and one bladder cancer. Recommended doses for phase II trials are 800 mg/m2 q 4 weeks for patients who have received less than or equal to 3 cytotoxic agents and 650 mg/m2 q 4 weeks for heavily pretreated patients.

Adult↗
PubMed1985

Broad-host-range plasmid vector for the in vitro construction of transcriptional/translational lac fusions.

A broad-host-range plasmid was constructed that allows the in vitro formation of beta-galactosidase fusions. DNA from the photosynthetic bacterium Rhodopseudomonas sphaeroides was cloned into this plasmid and a number of R. sphaeroides isolates were recovered that had varying levels of beta-galactosidase activity. beta-galactosidase antigenic activity from the fusion strains could be localized immunologically in polypeptides with an Mr of 120 000 or greater. Expression of beta-galactosidase activity under control of fusion derivatives was either very low or nonexistent in Escherichia coli relative to R. sphaeroides, indicating that R. sphaeroides promoters or translational start signals function poorly in E. coli.

Cell Compartmentation↗
PubMed1985

Specular microscopic follow-up of corneal grafts for pseudophakic bullous keratopathy.

Pseudophakic bullous keratopathy (PBK) has become the leading indication for penetrating keratoplasty. In our initial fifty patients having keratoplasty for PBK there was gradual loss of clear grafts in patients with retained intraocular lenses (IOLs). Specular microscopy was performed on donor tissue, and periodically postoperatively, for 130 grafts for PBK. The highest cell loss at one year was in eyes with retained iris support (39.2%) or anterior chamber (37.2%) IOLs. Cell loss in grafts with removed iris support IOLs (21.3%) was significantly less. When iris support IOLs were exchanged for anterior chamber (AC) IOLs, the cell loss at one year (27.1%) was intermediate. We recommend that iris support IOLs be removed at keratoplasty. Exchange for an AC IOL should be considered depending on the visual needs of each patient. Removal of AC IOLs should be based on consideration of prior tolerance and position of the implant.

Aged↗