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Biomedical subjects

S Kaplan

Publications and source records attributed to S Kaplan.

At least 289 records · Page 16Linked to original sources
PubMed1986

Sirenomelia: analysis in the cadmium- and lead-treated golden hamster.

Sirenomelia, a fusion of the lower extremities, is believed to result from a median, bilateral symmetric defect of the caudal portion of the embryo at a very early stage in development. Anomalies of the gastrointestinal and urogenital systems are commonly associated with this malformation. Sirenomelia is not an embryo-lethal condition but typically is incompatible with postnatal life when combined with the associated malformations. In this study, intravenous treatment of hamsters with a combination of cadmium and lead on the morning of the eighth day of gestation resulted in 1.4, 22.2, and 35.6% of the viable fetuses displaying sirenomelia in litters recovered on days 15, 12, and 10 of gestation, respectively. With the exception of several fetuses with exencephaly, most structures cranial to the level of the umbilicus were normal. Caudal abdominal and pelvic structures were severely affected, with agenesis or dysgenesis of the kidneys, bladder, umbilical arteries, and external genitalia frequently noted. The administration of a combination of cadmium and lead has proven to be an effective and consistent means of inducing sirenomelia in the golden hamster.

Animals↗
PubMed1986

Pinhole radionuclide ventriculography in small infants.

Radionuclide equilibrium gated ventriculograms were performed in 23 infants before and after surgery for congenital heart disease using standard parallel hole general purpose collimation followed by a pinhole collimation technique to magnify images and improve spatial resolution. A second group of nine infants had pinhole collimated gated ventriculography during cardiac catheterization for comparison with cineangiographic ejection fraction. In group I, pinhole collimation gave improved ventricular and atrial separation over general purpose parallel collimation for determination of left ventricular ejection fraction (42 of 42 studies calculable vs 37 of 42) and for right ventricular ejection fraction (36 of 37 studies calculable vs 20 of 37). In patients with transposition, pinhole technique allowed right ventricular ejection determination in nine of nine studies but in only one of nine was right ventricular ejection fraction possible by standard parallel collimation. In group II, the correlation between left ventricular ejection fraction by cineangiography and pinhole radionuclide ventriculography was excellent (r = 0.95). The correlation for right ventricular ejection fraction between cineangiography and pinhole radionuclide ventriculography was 0.82. Pinhole radionuclide ventriculography is a useful, practical clinical tool that can be used to assess ventricular function in small infants in an intensive care or outpatient setting.

Age Factors↗
PubMed1986

Left ventricular function in normal newborn infants and asymptomatic infants with neonatal polycythemia.

Digitized M-mode echocardiography was used to evaluate left ventricular (LV) function in normal neonates and to document subtle abnormalities of LV function in 19 asymptomatic newborn infants with polycythemia and hyperviscosity. Echocardiograms were performed before and after partial exchange transfusion and at 48 hours of age. Results were compared to those obtained from analysis of echocardiograms from 18 normal infants with normal hematocrits at 12 and 48 hours of age. In the normal group there were no differences between the digitized indices of LV function at 12 hours and those at 48 hours of age. In the polycythemic group, prior to hemodilution, the peak rate of LV emptying was low compared to normal values (-3.1 +/- 0.7 sec-1 vs -3.6 +/- 1.0 sec-1, p less than 0.05) and normalized following the procedure to -3.7 +/- 1.3 sec-1. The peak rate of left ventricular posterior wall (LVPW) thickening also increased following partial exchange transfusion (3.2 +/- 0.6 sec-1 to 3.7 +/- 1.0 sec-1, p less than 0.05). At 48 hours of age peak rates of change for the left ventricle (-2.9 +/- 0.8) and LVPW (3.0 +/- 0.7) were abnormally low in the polycythemic infants, all of whom had undergone partial exchange transfusion. Also, at 48 hours, the LVPW time to peak rate of thickening and time to the end of thickening were prolonged. In addition, the peak rate of LV filling in diastole was low in the polycythemic group (3.0 +/- 0.9 sec-1 vs 3.9 +/- 1.3 sec-1, p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Viscosity↗
PubMed1986

Etoposide, cisplatin and doxorubicin in patients with small cell lung cancer: tumor response and long term survival.

One hundred and fourteen patients with small cell lung cancer received a combination of etoposide 80 mg/m2 IV days 1,2,3,15,16,17, cisplatin 20 mg/m2 IV days 1,2,3 and doxorubicin 40 mg/m2 IV day 1, repeated every 4 weeks. The observation time from the initiation of treatment is longer than 4 years for all patients. An 85% response rate (38% complete response) was obtained after 1-4 cycles in 105 evaluable patients (96 without prior antitumour treatments). The response rate was not influenced by initial performance status and minimally by disease extension, whereas the same prognostic factors correlated significantly with complete responses. For limited disease and WHO performance 0 all responses were complete. For extensive disease and performance 3 no complete response was obtained. Various chemotherapy regimens with or without radiotherapy were used during the maintenance phase. Forty five per cent of first relapses were in the lung or mediastinum and 18% in the nervous system (20% without and 7% with prophylactic cranial irradiation). The median survival was 13.4 months for limited and 8.5 months for extensive disease, and correlated with performance and response. Only 2 patients survived free of disease after 4.8 and 5.5 years. We conclude that the induction treatment as used here produces a high rate of partial and complete responses but a low rate of long survivors.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1986

Candida retinitis in bare lymphocyte syndrome.

Bare lymphocyte syndrome (BLS) is a rare, severe combined immunodeficiency characterized by lack of expression of HLA A, B and C antigens and the absence of B2 microglobulins. Patients with BLS exhibit functional deficiency of both T and B cells resulting in bacterial as well as viral and fungal infection. Ophthalmic findings in this group of disorders have not been reported. We present a case of candida retinitis in a terminally ill 5-year-old girl with BLS.

Amphotericin B↗
PubMed1986

Coronary artery caliber in normal children and patients with Kawasaki disease but without aneurysms: an echocardiographic and angiographic study.

A total of 110 children aged 3 months to 16 years underwent two-dimensional echocardiography of the coronary arteries. Forty-two normal subjects and 68 patients with Kawasaki disease were evaluated. All 68 patients with Kawasaki disease underwent selective coronary arteriography. The objectives of this study were to 1) develop a normal profile of the proximal left and right coronary arteries as to caliber and shape in infants, toddlers and children using echocardiography; 2) compare the dimensions and shape of the coronary arteries of patients with Kawasaki disease but no obvious aneurysms with those of the coronary arteries of normal children; and 3) develop criteria that would permit distinguishing a large but normal coronary artery from a true aneurysm in patients with Kawasaki disease. In the normal subjects and patients with Kawasaki disease, the caliber of the coronary arteries showed little variability from the ostium to 10 mm distally, and ranged in size from 2 mm in infants to 5 mm in teenagers. There was no significant difference between male and female subjects. The feature that distinguished the large but normal coronary artery without aneurysm from that with an aneurysm was its uniformity of caliber. Also, the caliber of the opposite coronary artery was generally at the lower limits of normal. It appears that the proximal coronary arteries of infants and children can be accurately assessed using high resolution two-dimensional echocardiography, and that sequential evaluation of subtle changes over time may be performed.

Adolescent↗
PubMed1986

Sensitivity, specificity and predictive value of two-dimensional echocardiography in detecting coronary artery aneurysms in patients with Kawasaki disease.

Seventy-seven patients with Kawasaki disease were prospectively evaluated from 1978 to 1983 to determine the sensitivity, specificity and predictive value for detecting coronary artery aneurysms with two-dimensional echocardiography. Seventy (91%) underwent selective coronary arteriography and are included in this report. The study was divided into two periods because of increased experience and the use of a systematic approach with two-dimensional echocardiography in the second period as compared with the first. Aneurysms were demonstrated in nine patients (13%). The coronary artery system was divided into six regions: proximal third of the main right coronary artery, distal right coronary artery, left main coronary artery, left anterior descending coronary artery, circumflex coronary artery and distal left coronary artery. The sensitivity and specificity were high when imaging the proximal regions, and improved from the first period to the second. Both sensitivity and specificity were lower for the more distal regions of the right and left coronary arteries. Overall, the sensitivity of two-dimensional echocardiography was 100% because there were no patients in our study who had isolated distal coronary artery aneurysms. Two-dimensional echocardiography is a sensitive and specific test for detecting aneurysms in the proximal portions of both the right and left coronary arteries, and is useful in selecting patients for invasive investigation with selective coronary arteriography.

Adolescent↗
PubMed1986

In vitro biosynthesis and membrane association of photosynthetic reaction center subunits from Rhodopseudomonas sphaeroides.

The reaction center of Rhodopseudomonas sphaeroides is an integral membrane protein complex responsible for primary photochemical charge separation in photosynthesis. We report the synthesis of two of the three subunits of the photosynthetic reaction center using a DNA-directed in vitro transcription-translation system prepared from R. sphaeroides. The in vitro-synthesized polypeptides, as resolved by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, had apparent Mrs of 24,000 and 21,000 and were shown to be synthesized in equimolar amounts. This corresponds precisely to the in vivo reaction center subunits M and L, respectively. The in vitro-synthesized polypeptides were immunoprecipitated with antibody prepared against whole native reaction centers. In addition, the identity of the in vitro-synthesized polypeptides as L and M was verified by comparing the protease digestion products of in vivo- with in vitro-synthesized reaction center subunits. Both of the in vitro-synthesized polypeptides were also found to partition with the particulate material in the transcription-translation system and to associate with added membranes.

Bacterial Proteins↗
PubMed1986

Cloning and expression of the Rhodobacter sphaeroides reaction center H gene.

The Rhodobacter sphaeroides structural gene (puhA) for the reaction center H polypeptide has been identified and cloned by using restriction fragements specific for the analogous Rhodobacter capsulatus gene as a heterologous hybridization probe. The presence of puhA on a 1.45-kilobase BamHI restriction fragment was confirmed by partial DNA sequence analysis and by the synthesis of an immunoreactive Mr-28,000 reaction center H polypeptide in an R. sphaeroides coupled transcription-translation system. Approximately 450 base pairs of DNA upstream of the puhA gene were sufficient for expression of this protein in vitro. Northern RNA-DNA blot analysis with an internal puhA-specific probe identified at least two, apparently monocistronic, transcripts present at different cellular levels under physiological conditions known to affect the cellular content of both reaction center complexes and photosynthetic membrane. Northern blot analysis with specific upstream restriction fragment probes revealed that the 1,400-nucleotide puhA-specific mRNA had a 5' terminus upstream of the 1,130-nucleotide transcript. Both puhA-specific mRNA and immunoreactive reaction center H protein were detectable in chemoheterotrophically grown cells which lacked detectable bacteriochlorophyll and photosynthetic membrane.

Anaerobiosis↗
PubMed1986

Cloning, DNA sequence, and expression of the Rhodobacter sphaeroides cytochrome c2 gene.

The Rhodobacter sphaeroides cytochrome c2 functions as a mobile electron carrier in both aerobic and photosynthetic electron transport chains. Synthetic deoxyoligonucleotide probes, based on the known amino acid sequence of this protein (Mr 14,000), were used to identify and clone the cytochrome c2 structural gene (cycA). DNA sequence analysis of the cycA gene indicated the presence of a typical procaryotic 21-residue signal sequence, suggesting that this periplasmic protein is synthesized in vivo as a precursor. Synthesis of an immunoreactive cytochrome c2 precursor protein (Mr 15,500) was observed in vitro when plasmids containing the cycA gene were used as templates in an R. sphaeroides coupled transcription-translation system. Approximately 500 base pairs of DNA upstream of the cycA gene was sufficient to allow expression of this gene product in vitro. Northern blot analysis with an internal cycA-specific probe identified at least two possibly monocistronic transcripts present in both different cellular levels and relative stoichiometries in steady-state cells grown under different physiological conditions. The ratio of the small (740-nucleotide) and large (920-nucleotide) cycA-specific mRNA species was dependent on cultural conditions but was not affected by light intensity under photosynthetic conditions. Our results suggest that the increase in the cellular level of the cytochrome c2 protein found in photosynthetic cells was due, in part, to increased transcription of the single-copy cyc operon.

Base Sequence↗
PubMed1986

Duration of ventricular ejection during spontaneous breathing and positive pressure ventilation in newborn infants.

Experimental manipulations of intrathoracic pressure at the investigational level have been shown to result in demonstrable changes in ventricular outputs. To assess whether these changes are detectable in the clinical setting of newborn infants, we evaluated changes in the duration of left and right ventricular ejection during spontaneous breathing and during positive pressure ventilation. This was accomplished by measuring left and right ventricular ejection times (VETs) using echocardiography. Values from cardiac cycles during peak inspiration were compared to cycles that occurred during expiration. In 6 infants breathing spontaneously, the mean duration of right VET increased by 4.0% at peak inspiration, while the concomitant mean left VET decreased by 3.3%. In 14 infants requiring positive pressure ventilation, the mean duration of right VET decreased by 7.2% at peak inspiration, while the left VET increased by 2.5%. We conclude that changes in intrathoracic pressure associated with spontaneous breathing and with positive pressure ventilation result in detectable changes in ventricular ejection in the newborn infant.

Echocardiography↗
PubMed1986

Mortality among industrial workers exposed to formaldehyde.

A historical cohort study evaluated the mortality experience of 26,561 workers employed in 10 formaldehyde-producing or -using facilities. Approximately 600,000 person-years of follow-up accrued as workers were followed to January 1, 1980. Estimates of historical exposure to formaldehyde by job were developed by project industrial hygienists using monitoring data available from participating plants, comments from long-term workers, and comprehensive monitoring data specifically collected for this study. Mortality from all causes combined was about as expected [standardized mortality ratio (SMR) = 96] based on mortality rates of the general U.S. population. Significantly fewer deaths occurred from infective and parasitic diseases (SMR = 51) and from accidents (SMR = 72) than expected. Cancer overall was not related to formaldehyde exposure. Workers exposed to formaldehyde had slight excesses for Hodgkin's disease and cancers of the lung and prostate gland, but these excesses were not consistently related to duration of or average, cumulative, or peak formaldehyde exposure levels. Recent animal studies found nasal cancer among rats exposed to formaldehyde, but no excess of this tumor occurred in this study. Mortality from brain cancer and leukemia among these industrial workers was not excessive in contrast to reported excesses among professional groups (e.g., anatomists, embalmers, and pathologists) with exposure to formaldehyde. Although there was a deficit for cancer of the buccal cavity and pharynx, mortality from certain subsites, i.e., the nasopharynx and oropharynx, was elevated. These subsites did not, however, show a consistently rising risk with level of exposure. These data provide little evidence that mortality from cancer is associated with formaldehyde exposure at levels experienced by workers in this study.

Adult↗
PubMed1986

The effect of predetermined thrombotic potential of the recipient on small-caliber graft performance.

This study was designed to establish the influence of the recipient's thrombotic potential on the patency of small-caliber prostheses and to evaluate the subsequent improvement of graft performance by medicinally altering the prostaglandin balance in subjects predisposed to graft occlusion. Mongrel dogs were pretested and classified as low and high responders according to their thrombotic potential, measured as prostaglandin metabolite balance and platelet aggregability. High responders were randomly divided into two groups. Those assigned to serve as the medicated subjects were pretreated 1 week before surgery with a single oral daily administration of combined dazmegrel (UK-38,485) and aspirin in equal dosages of 3 mg/kg. Medication was continued throughout the experiment. Dacron grafts were implanted bilaterally in the carotid artery site in all subjects. Following a 3-week implantation period, the patency rate for the group with low thrombotic potential was 100%. In the animals with high thrombotic potential the patency rate was 10% for nonmedicated subjects and 100% for medicated subjects. These data support the concept that the thrombotic potential largely determines the capacity of the recipient's blood to thrombose small-caliber prostheses. Effective medicinal alteration of prostaglandin balance results in exceptionally increased patency of synthetic grafts.

Animals↗
PubMed1986

The generalized atrophic benign form of junctional epidermolysis bullosa. Experience with four patients in the United States.

We encountered four patients in the United States with the generalized atrophic benign form of junctional epidermolysis bullosa (epidermolysis bullosa atrophicans generalisata mitis, nonlethal junctional epidermolysis bullosa). Prior to the performance of definitive diagnostic studies, each patient had been thought for at least a decade to have either a dystrophic or simplex form of epidermolysis bullosa. Each patient had generalized blisters since birth that healed with atrophy and mild scarring but without milia or contractures. Two of the four patients had experienced laryngeal involvement during childhood. In each patient, correct diagnosis was finally established by either electron microscopic examination or immunofluorescence mapping of skin sections from induced blisters.

Adolescent↗