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Biomedical subjects

S Samuelson

Publications and source records attributed to S Samuelson.

8 recordsLinked to original sources
PubMed2001

Effects of alveolar surfactant aggregates on T-lymphocyte proliferation.

The effects of alveolar large aggregate (LA) and small aggregate (SA) surfactant subfractions isolated from healthy adult rats on mitogen-stimulated proliferative responses of human peripheral blood mononuclear cells (PBMC) was examined. Various concentrations of total surfactant suppressed proliferation of stimulated lymphocytes by up to 95% of mitogen-stimulated cells alone. LA subfractions of total surfactant had no effect on proliferation, whereas SA significantly enhanced the lymphocyte proliferation at lower concentrations (7.8 microg/ml) compared to mitogen-stimulated cells alone. Higher concentrations of SA (62.5 microg/ml) inhibited lymphocyte proliferation. This concentration-dependent effect of SA on proliferation of PBMC was also present when cells were stimulated with various lectins including anti-CD3, concanavalin A and phytohemagglutinin. Analysis of the supernatant of mitogen-stimulated cell cultures treated with inhibitory concentrations of SA showed decreased amounts of interleukin (IL)-2, compared to cells alone, which could be reversed by adding exogenous IL-2 to the cell cultures with the SA. These results suggest that alveolar surfactant subfractions have distinct functions within the alveoli, both biophysically and with respect to their effects on the host's immunomodulatory responses.

Animals↗
PubMed2001

Genomewide survey of panic disorder.

We completed a genome scan of 23 multiplex families of panic disorder. Ninety family members had DSM-III-R panic disorder, and another 23 had recurrent, spontaneous panic attacks that did not satisfy these criteria. We typed 469 markers from the CHLC map (ver 8c7) with an average intermarker distance of 10.3 cM. Two-point lod scores were calculated with both a dominant and a recessive model, and maps of lod scores < -2.00, assuming genetic homogeneity, were constructed by using DSM-III-R panic disorder as the affected phenotype. Lod scores were < -2.00 over 94-95% of the genome. The greatest lod score was 2.23 (theta = 0.15) at the D7S2846 locus, located at 57.8 cM on chromosome 7 according to the Marshfield Clinic map. Flanking markers analyzed in a nonparametric, multipoint analysis using GENEHUNTER resulted in an NPL score of 2.97 at 63 cM on the Marshfield map. This region lies within 15 cM from the D7S435 locus, where Knowles et al. [1998] obtained a lod score of 1.71 (theta = 0.10) for panic disorder (now 2.45 with the addition of new families; James Knowles, personal communication). Thus, the maximum evidence of linkage from two genome scans of panic disorder lies within a small region of chromosome 7p.

Adult↗
PubMed1993

Comparison of clinical and echocardiographic determinations of left ventricular dimension during weaning from cardiopulmonary bypass.

Twenty patients (age 45 to 78 years) were studied with ethical committee approval and informed patient consent during coronary artery bypass grafting. Transesophageal echocardiography (TEE) was used to validate a clinical measure of preload: inspection of the line of contact between the heart (acute margin) and the diaphragm. Immediately before going on cardiopulmonary bypass (CPB), with the cannulas and stay sutures in place, a small mark was made with the cautery on the diaphragm at the line of contact. After CPB the patients were transfused from the extracorporeal circuit to exactly the same level. At these two times, TEE recordings of the short axis of the left ventricle were performed and stored on videotape for later blinded evaluation off-line. The left ventricle short-axis area in end-diastole measured after CPB showed a close correlation to that measured before CPB, r = 0.88, P < 0.001. The regression line was close to the line of identity. The conclusion was that inspection of the line of contact between the heart and the diaphragm can be used clinically during weaning from bypass to obtain the same left ventricular end-diastolic volume as before CPB.

Aged↗
PubMed1991

A comparison between morphine, meperidine and ketobemidone in continuous intravenous infusion for postoperative relief.

Morphine, meperidine and ketobemidone used in continuous i.v. infusion for postoperative pain relief were compared in a double-blind, controlled, prospective study in 81 consecutive consenting adult patients after open-heart surgery, with permission from the hospital ethics committee. During the first postoperative period, the infusion rates were fixed. Later on, when the infusion rate could be regulated according to individual patient needs, the variation in infusion rate was large, in accordance with earlier studies. No significant differences were demonstrated between the three analgesics with respect to efficacy of analgesia or side effects like shivering, nausea or vomiting. Respiratory depression following extubation was not observed. During shivering, there was a significant increase in the arterio-mixed venous difference of oxygen in all groups. The amounts of opioids used were relatively small compared to amounts used in patients following abdominal surgery. When interviewed some days after surgery, 18/74 patients remembered moderate pain and 11 severe pain during the stay in the ICU.

Double-Blind Method↗
PubMed1990

Close linkage between panic disorder and alpha-haptoglobin excluded in 10 families.

We previously reported a lod score of 2.3 suggesting linkage between panic disorder and the alpha-haptoglobin locus on chromosome 16q22 in 26 pedigrees. In the present study we tested for linkage between alpha-haptoglobin and panic disorder in 10 new pedigrees and excluded a gene for panic disorder from 6 centimorgans (recombination fraction, 0.06) surrounding the alpha-haptoglobin locus. The data were analyzed under a variety of assumptions about the transmission of panic disorder, and linkage was excluded by all genetic models but one. When lod scores from the present set of 10 pedigrees were pooled with those from the first 26, no evidence of genetic heterogeneity was found, and the maximum lod score was 0.67 at a recombination fraction of 0.17. Taken as a whole, the present findings do not support the presence of a disease gene for panic disorder closely linked to the alpha-haptoglobin locus on chromosome 16q22.

Adult↗
PubMed1990

Usher's syndrome.

Usher's syndrome is an autosomal recessive condition of congenital sensorineural hearing loss and retinitis pigmentosa. Other abnormalities are present but inconsistently, suggesting the genetic concepts of pleiotropy and heterogeneity. Accordingly, several classifications have been suggested. Clinical findings involve the visual, auditory and vestibular systems. The identification of the carrier state would allow for more timely and accurate genetic counselling. A screening program for Usher's syndrome appears feasible. This would allow affected, deaf individuals to prepare themselves for the expected visual loss giving them a better chance for a productive, fulfilling life.

Genetic Counseling↗