PubMed Health⌕ Search

Biomedical subjects

A Rothman

Publications and source records attributed to A Rothman.

At least 19 recordsLinked to original sources
PubMed1992

Effect of ethanol on the Na(+)- and the Na+,K(+)-ATPase activities of basolateral plasma membranes of kidney proximal tubular cells.

The Na(+)- and the Na+,K(+)-ATPase activities of basolateral plasma membranes from rat kidney proximal tubular cells were affected differentially by ethanol. Moreover, at concentrations of ethanol that can be reached in vivo in the blood plasma (50 mM) there was a significant effect on the Na(+)-ATPase activity and practically no effect on the Na+,K(+)-ATPase activity.

Adenosine Triphosphatases↗
PubMed1992

An objective structured clinical examination for the licentiate: report of the pilot project of the Medical Council of Canada.

The Medical Council of Canada (MCC) administers a qualifying examination for the issuance of a license to practice medicine. To date, this examination does not test the clinical skills of history taking, physical examination, and communication. The MCC is implementing an objective structured clinical examination (OSCE) to test these skills in October 1992. A pilot examination was developed to test the feasibility, reliability, and validity of running a multisite, two-form, four-hour, 20-station OSCE for national licensure. In February 1991, 240 volunteer first- and second-year residents were tested at four sites. The candidates were randomly assigned to one of two forms of the test and one of two sites for two of the four sites. Generalizability analysis revealed that the variance due to form was 0.0 and that due to site was .16 compared with a total variance of 280.86. The reliabilities (inter-station) were .56 and .60 for the two forms. Station total-test score correlations, used to measure station validity, were significant for 38 of the 40 stations used (range .14-.60). The results of the OSCE correlated moderately with the MCC qualifying examination; these correlations were .32 and .35 for the two test forms. Content validity was assessed by postexamination questionnaires given to the physician examiners using a scale of 0 (low) to 10 (high). The physicians' mean ratings were: importance of the stations, 8.1 (SD, 1.8); success of the examination in testing core skills, 8.1 (SD, 1.6); and degree of challenge, 7.8 (SD, 2.1). The results indicate that a full-scale national administration of an OSCE for licensure is feasible using the model developed. Aspects of validity have been established and strategies to augment reliability have been developed.

Canada↗
PubMed1992

Intraluminal ultrasound imaging through a balloon dilation catheter in an animal model of coarctation of the aorta.

BACKGROUND: Controversy still exists over the optimal balloon size, extent of vascular disruption, and long-term results of balloon dilation therapy for coarctation of the aorta. Intravascular ultrasound imaging has been used in patients with coronary artery disease to provide further insight into the anatomy of atherosclerotic lesions and the results of angioplasty and atherectomy. Initial observations of the results of balloon dilation of coarctations with intravascular ultrasound imaging have shown prominent dissections of the inner vascular layers that are often not detected by angiography. The purpose of this study was to test a new transballoon catheter ultrasonic imaging system capable of on-line direct visualization of lumen diameter and vessel wall structure for imaging before, during, and after dilation in an acute animal model of aortic coarctation. METHODS AND RESULTS: Abdominal aortic coarctations were created surgically in three 14-19-kg mongrel dogs by using Teflon gauze ties. The 6.8F ultrasound balloon catheter was placed percutaneously in the right femoral artery through a 9F sheath. Ultrasound imaging allowed measurement of the coarctation diameter, characterization of the vessel wall structure, localization of the stenosis, and placement of the midportion of the balloon at the narrowest area. Imaging through the balloon was performed through several dilations (five to eight per animal), and after balloon deflation, it provided information on postdilation diameter, intimal tears, long-segment dissections, and intramural thrombi, findings that were confirmed at postmortem examination. CONCLUSIONS: The results of this study demonstrate that imaging with a new intraballoon ultrasound device is feasible during inflation to therapeutic dilation pressures; it allows visualization of the changes in diameter and vascular wall structure after serial dilations without having to recross the obstructed area. Adaptation to larger balloon sizes and lower frequencies should make this system applicable to interventional catheterizations in patients with congenital cardiac and vascular lesions.

Animals↗
PubMed1992

Transesophageal echocardiography in infants and children with congenital heart disease.

TEE applications for children and infants with congenital heart disease are now clinically established and TEE is being used in most major pediatric cardiovascular centers. This technology has evolved to the point that it is capable of providing diagnostic quality imaging, even for small infants. With expanding technology and increasing experience, new and more sophisticated applications will be found for pediatric TEE.

Child↗
PubMed1992

Development and characterization of a cloned rat pulmonary arterial smooth muscle cell line that maintains differentiated properties through multiple subcultures.

BACKGROUND: Pulmonary hypertension is associated with abnormal pulmonary arterial contractility and growth. The mechanisms for these abnormalities are largely unknown. To study these processes, we sought to develop an in vitro system. Even though cultured aortic and pulmonary artery smooth muscle cells (SMCs) have been of considerable value in studying smooth muscle biology, one drawback of this system has been that these cells often lose differentiated properties in an unpredictable manner when they are passaged in culture. In addition, there appear to be significant differences in physiological and pathological responses between the systemic and pulmonary circulations, many of which could be directly related to the smooth muscle. We therefore established a cloned population of rat pulmonary arterial SMCs (PASMCs) that maintain differentiated properties through multiple subcultures. METHODS AND RESULTS: PASMCs were obtained initially by enzymatic dissociation from pulmonary arteries of adult Sprague-Dawley rats. From these cells, clones were isolated. The cloned cells retained expression of functional surface receptors for angiotensin II, norepinephrine, and alpha-thrombin and high levels of the smooth muscle isoforms of alpha-actin, myosin heavy chain, myosin regulatory light chain, and alpha-tropomyosin mRNAs even after multiple passages. The cells could also be transfected and processed exogenous transcripts in a smooth muscle-specific fashion. CONCLUSIONS: These cloned PASMCs retain many differentiated characteristics and should be valuable for future studies of pulmonary vascular smooth muscle cell biology.

Animals↗
PubMed1991

Stretch increases inositol trisphosphate and inositol tetrakisphosphate in cultured pulmonary vascular smooth muscle cells.

There are no reports of the effect of stretch on inositol phosphates in smooth muscle. Phosphoinositide and inositol phosphate metabolism was studied in cultured rat vascular smooth muscle cells subjected to stretching. The masses of inositol trisphosphate and tetrakisphosphate increased (+34 +/- 7% and +58 +/- 12%, respectively; p less than 0.001) after 25 s of a single 20% stretch and had returned to control levels by 45 s; phosphatidylinositol, phosphatidylinositol phosphate and bisphosphate did not change. Repetitive stretch did not alter the masses of any of the compounds. A single stretch also increased 45Ca2+ efflux (+52 +/- 5%, p less than 0.01). These data suggest that stretch of cultured vascular smooth muscle can elicit a rapid, short-lived increase in inositol phosphates, which may subsequently affect Ca2+.

Animals↗
PubMed1990

Ruptured arteriovenous malformation complicating thrombolytic therapy with tissue plasminogen activator.

It is though that the clot-specific activity of tissue plasminogen activator, used in the treatment of acute myocardial infarction, makes bleeding complications less common than does the use of either streptokinase or urokinase. The incidence of intracerebral hemorrhage complicating the use of tissue plasminogen activator has been estimated to be 0.68%. This is a report of the rupture of an intracranial arteriovenous malformation complicating the use of tissue plasminogen activator therapy. Theories for the mechanism of hemorrhage in this instance are presented, as are suggestions for future use of the enzyme.

Aged↗
PubMed1990

Early results and follow-up of balloon angioplasty for branch pulmonary artery stenoses.

Two hundred eighteen balloon angioplasty procedures were performed in 135 patients with branch pulmonary artery stenoses from June 1984 to February 1989. Arteries were dilated in patients with tetralogy of Fallot (n = 49), tetralogy of Fallot/pulmonary atresia (n = 64), isolated peripheral pulmonary artery stenoses (n = 58) and "other" lesions (the majority had truncus arteriosus or single ventricle and surgically induced pulmonary artery stenoses (n = 47). Mean age at dilation was 6.6 +/- 6.3 years (range 1 month to 38.5 years). The mean diameter of the lesion increased from 3.8 +/- 1.7 to 5.5 +/- 2.1 mm with dilation (p = 0.001). The overall success rate was 58% (127 of 218 dilations), assessed by the following criteria: an increase greater than or equal to 50% of predilation diameter, an increase greater than 20% in flow to the affected lung or a decrease greater than 20% in systolic right ventricular to aortic pressure ratio. Success did not correlate with patient age. Mean balloon to artery ratio was higher in successful (4.2) than in failed (3.0) angioplasty procedures (p = 0.0001). There were four early deaths: two of the patients had pulmonary artery rupture with angioplasty performed less than 1 month after pulmonary artery surgery. An aneurysm occurred in 11 arteries and transient pulmonary edema in four patients. At angiography performed a mean of 10 months (range 1 to 54) after dilation, the mean diameter of 57 arteries was unchanged (5.5 versus 5.4 mm). However, 5 of 32 initially successfully dilated vessels had returned to predilation size as a result of restenosis.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1990

Reliability and validity of the objective structured clinical examination in assessing surgical residents.

The purpose of this research was to assess reliability and construct validity of the objective structured clinical examination (OSCE) for evaluating the clinical skills of surgical residents. Reliability refers to precision of the examination and construct validity to the degree to which the examination can discriminate between different levels of training. Twenty-seven second postgraduate year surgical residents took a 38-station OSCE representing seven surgical specialties and that tested history-taking, physical examination, problem-solving, technical skills, and attitudes. A couplet methodology was used wherein a patient encounter was followed by written questions aimed at testing problem-solving and patient management capabilities. Thirty-six standardized patients were trained and 36 surgeons served as examiners marking from structured checklists. Overall reliability, Cronbach's alpha, was 0.89. Construct validity was examined by comparing the scores of the residents with those of a group of graduates of foreign medical schools applying for a "pre-internship" program. For 17 of 19 stations that both groups took, the residents performed significantly better (p less than 0.01). Individual station validity was significant for 32 of 38 stations (r = 0.36 to 0.82, p less than 0.05). The examinations took 3.83 hours at a cost of $5,293 (Canadian dollars). The OSCE has been shown to be a reliable method of assessing clinical skills of surgical residents, construct validity has been established, and inter-item validity confirmed. Reliabilities achieved exceed those traditionally required for both acceptance and promotion decisions.

Analysis of Variance↗
PubMed1990

Balloon dilation of branch pulmonary artery stenosis.

We consider balloon angioplasty to be an established, highly useful procedure in the management of branch pulmonary artery stenosis. It is successful in approximately 60% of cases. Current figures would indicate a low but significant mortality rate (1%) and a risk of aneurym formation (3%). Patients undergoing balloon angioplasty in the acute postpulmonary artery surgical period constitute a particularly high risk group for vessel rupture. Restenosis after branch pulmonary dilation is infrequent, but does occur. Further improvements in the use of this procedure should probably involve the use of expandable intravascular stents for patients with failed dilations or evidence of restenosis.

Aneurysm↗
PubMed1989

Pulmonary hypertension and asthma in two patients with congenital heart disease.

Reactive airway disease has only rarely been associated with pulmonary hypertension. We treated two patients with congenital heart disease and asthma who had increased pulmonary arterial pressure at cardiac catheterization. Pulmonary hypertension could not be explained solely by the cardiac lesion, nor by respiratory mechanical factors, as the patients did not have wheezing during the catheterization study. After long-term treatment with bronchodilators, corticosteroids, and oxygen, and coincident with improvement in the airway disease, there was catheterization-proved diminution of pulmonary hypertension. Whether asthma and pulmonary hypertension were causally linked is unknown, but further work seems indicated to elucidate the relationship between bronchoconstriction and pulmonary vasoconstriction. Furthermore, aggressive management of even mild reactive airway disease may be warranted in patients with pulmonary hypertension, regardless of apparent cause.

Asthma↗
PubMed1989

Upper thoracic disk herniation secondary to vertebral metastases.

Thoracic disk herniations are exceedingly rare, particularly those in the upper thoracic region. The etiology of these protrusions is generally considered to be either traumatic or degenerative in nature. A case of upper thoracic disk herniation secondary to destructive changes caused by breast cancer metastatic to the vertebral body is presented.

Aged↗
PubMed1987

Incisional adenocarcinoma after intracranial metastasis resection.

Skin and subcutaneous secondary tumors are unusual, especially in cases of colonic adenocarcinoma. They usually signify disseminated metastases. A rare case of an isolated incisional tumor after resection of a metastasis to the cerebellum is presented. The pathophysiology and management of such an event is discussed. The clinical setting suggests that this occurrence represented the result of microscopic deposits of neoplastic cells in the wound rather than hematogenous spread.

Adenocarcinoma↗