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Biomedical subjects

M Tobin

Publications and source records attributed to M Tobin.

At least 37 records · Page 2Linked to original sources
PubMed1993

Doppler echocardiographic evidence of left ventricular diastolic dysfunction in ankylosing spondylitis.

Although cardiac involvement in the form of conduction abnormalities or aortic regurgitation occurs in 5 to 10% of patients with ankylosing spondylitis, few studies have assessed left ventricular (LV) function. This study assesses the prevalence of both systolic and diastolic LV dysfunction and other cardiac abnormalities in patients with ankylosing spondylitis who have no clinical cardiac manifestations. Fifty-nine patients (49 men and 10 women, mean age 42 +/- 10 years) underwent full clinical examination, electrocardiography, 24-hour Holter monitoring and 2-dimensional, M-mode and Doppler echocardiography. Mean disease duration was 17 +/- 9 years (range 1 to 42). Seventeen patients had evidence of noncardiac extraarticular manifestations. Precordial examination was normal in all. An age- and sex-matched control group of 44 healthy subjects was also studied. On echocardiography, abnormal LV diastolic function was detected in 12 patients (20%). Prolonged isovolumic relaxation time, prolonged deceleration time, reduced rate of descent of flow velocity in early diastole (EF slope) and reversal of the early and late peak transmitral diastolic flow velocities (E/A ratio) were noted in 9 patients. In 3 patients there was an increased E/A ratio, reduced deceleration time and increased EF slope. Mild aortic regurgitation and mitral regurgitation was seen in 1 and 3 patients, respectively. No abnormalities of left atrial size, LV systolic or diastolic dimensions or wall thicknesses were noted. There was no correlation between the presence of LV diastolic dysfunction and age, disease severity, disease duration, or the presence of extraarticular manifestations.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Transition from clinician to manager--a case study.

The experiences of a group of five psychiatrists who made the transition from clinicians to managers in the Victorian Mental Health system are described. The paper reflects upon the action learning methodology for professionals in transition. Problems related to the painful gaining of experience, dissonance between the clinical and the management roles and the need to develop new rationalizations for understanding work are discussed.

Career Mobility↗
PubMed1993

Fair hearing testimony.

Realizing the competitive environment of medicine, the gold standard for credentials must remain training, experience, ability, and/or competence. These two doctors have met this standard. Family physicians have cesarean privileges in Memphis, Tenn.; Wichita, Kan.; Kansas City, Mo.; Rochester, Minn.; and numerous other cities across our state and nation. With access to perinatal care of critical importance, all physicians must practice medicine to their fullest capabilities. This hospital will greatly benefit from its support of fair privileging for family physicians. And the AAFP will vigorously defend each family physician's right to practice obstetrics on both a state and national level.

Cesarean Section↗
PubMed1991

Synthesis and characterization of magnetically responsive albumin microspheres containing cis-hydroxyproline for scar inhibition.

Magnetically responsive albumin microspheres containing the proline analog, cis-hydroxyproline, were synthesized and their in-vitro physical properties were characterized. These microspheres have an average size of 1.1 +/- 0.3 microns with 94% of the microspheres less than 2.0 microns. They are uniformly spherical and contain 67% albumin, 22% magnetite, and 8% cis-hydroxyproline. The cis-hydroxyproline is releasable during a 72-h period and demonstrates a slow, releasable pool that constitutes approximately 50% of the incorporated drug. cis-Hydroxyproline is neither chemically nor biologically altered during its incorporation into the microsphere. cis-Hydroxyproline release from microspheres results in the in vitro inhibition of collagen secretion, which is indistinguishable from unincorporated cis-hydroxyproline. In a rat-tail animal model these microspheres were selectively targeted using an external magnetic field applied to a 1.5-2.0-cm target site. Fifty to 80% of the infused microspheres were localized to this site, whereas without a magnetic field only 15-20% of the microspheres are localized to this site. cis-Hydroxyproline microspheres resulted in a 16% decrease in collagen content in a scar model when compared with untreated animals (p less than 0.05). With further refinement of this method of drug delivery, clinically useful inhibition of scar formation may result.

Animals↗
PubMed1990

Cerebral blood flow variations in CNS lupus.

We studied the patterns of cerebral blood flow (CBF), over time, in patients with systemic lupus erythematosus and varying neurologic manifestations including headache, stroke, psychosis, and encephalopathy. For 20 paired xenon-133 CBF measurements, CBF was normal during CNS remissions, regardless of the symptoms. CBF was significantly depressed during CNS exacerbations. The magnitude of change in CBF varied with the neurologic syndrome. CBF was least affected in patients with nonspecific symptoms such as headache or malaise, whereas patients with encephalopathy or psychosis exhibited the greatest reductions in CBF. In 1 patient with affective psychosis, without clinical or CT evidence of cerebral ischemia, serial SPECT studies showed resolution of multifocal cerebral perfusion defects which paralleled clinical recovery.

Adult↗
PubMed1989

Nonthromboembolic causes of high-probability lung scans.

Three cases of high-probability lung scans because of nonthromboembolic causes (dissecting thoracic aortic aneurysm, sarcoid with venous occlusion, and subclavian catheter misplacement) are presented along with a review of the literature.

Adult↗
PubMed1987

The cholescintigraphic pattern of small bowel obstruction.

An elderly patient presenting with acute abdominal pain, nausea, and vomiting underwent a hepatobiliary scan. This demonstrated normal filling of the gallbladder but dilatation of the small bowel, which was found to correspond radiographically to partial small bowel obstruction.

Aged↗
PubMed1987

Cerebellar glucose consumption in normal and pathologic states using fluorine-FDG and PET.

We studied cerebellar metabolism in 118 subjects including young and elderly controls and patients suffering from stroke, supratentorial brain tumor and Alzheimer's disease using fluorine-18 fluorodeoxyglucose ([18F]FDG) and position emission tomography (PET). Alzheimer's disease and normal aging did not alter mean cerebellar metabolism. In stroke and tumor mean cerebellar metabolism was lower in the hemisphere contralateral to the supratentorial lesion. In tumor bilaterally significant reductions in absolute cerebellar metabolism also were noted, unlike stroke. Primary sensory stimulation did not alter absolute or relative cerebellar metabolism. These results show that absolute and relative values for cerebellar metabolism vary depending on the process under study. Thus analysis schemes employing normalization of regional metabolic data to cerebellar values may be subject to error.

Adult↗
PubMed1984

Influenza B virus genome: complete nucleotide sequence of the influenza B/lee/40 virus genome RNA segment 5 encoding the nucleoprotein and comparison with the B/Singapore/222/79 nucleoprotein.

The complete nucleotide sequence of a cloned full-length DNA copy of genome RNA segment 5 of influenza B/Lee/40 virus has been determined. The genome segment is 1841 nucleotides in length and is capable of coding for a nucleoprotein (NP) of 560 amino acids. Comparison with the only other known sequence of an influenza B virus nucleoprotein gene (B/Singapore/222/79) indicates striking homology. Only 113 nucleotide substitutions are present between the two strains in their protein coding region and these lead to only 22 amino acid substitutions between nucleoproteins of identical polypeptide chain length. Assuming a common lineage, this reflects a calculated rate of amino acid sequence divergence of 0.1% per year. Like its influenza A virus counterpart, the influenza B/Lee/40 nucleoprotein is a basic protein with a relatively even distribution of its charged residues. The remarkable conservation of nucleoprotein primary structure over a 39-year period probably reflects both selection for performance of specific functions and protection from antigenic selection by the host immune system.

Amino Acid Sequence↗
PubMed1982

Angiotensin-induced sodium excretion patterns in cirrhosis: role of renal prostaglandins.

Changes in renal hemodynamics and sodium excretion induced by an angiotensin II (AII) infusion were correlated with urinary prostaglandin E2 (PGE2) excretion in 15 patients with cirrhosis and ascites. All induced natriuretic responses in 47% and antinatriuretic responses in 53% of the patients. Natriuresis was accompanied by an increase; antinatriuresis by a decrease in PGE2 excretion. Although there was no change in GFR (CIn), renal blood flow (CPAH) decreased. Patients were clinically indistinguishable. Antinatriuretic responders tended, however, to have higher baseline PGE2 excretion rates, were more sensitive to effects of prostaglandin blockade, and were less sensitive to the pressor effect of AII. Following partial inhibition of renal prostaglandin synthesis by indomethacin, AII-induced natriuretic responses were accentuated. GFR, RBF, and urine flow rate markedly decreased in both groups. There was no difference in pressor sensitivity to AII following prostaglandin synthesis blockade. We conclude that in patients with hepatic cirrhosis, the sodium excretion pattern induced by an exogenous AII challenge may depend on the prior state of intrarenal prostaglandin activity. Our findings also support the hypothesis that renal hemodynamic parameters in patients with cirrhosis and ascites are crucially dependent on renal prostaglandins.

Angiotensin II↗
PubMed1980

A macrofunction for computer processing of comprehensive renal function studies.

Details of a series of computer programs associated with a complex renal function procedure, all linked together into a single "macrofunction" are presented. Input consisted of not only in vivo nuclear medicine information, but also data concerning patient identification, urine volumes, voiding time, urine specific gravity, blood pressure and other pertinent information. Computer output consisted of images, curves and typed information presented in an integrated format ready for inclusion into the patient's record. Clinical evaluation of this comprehensive renal function macrofunction has proved to be useful, econominal, rapid and accurate. It has conveniently sorted a wide variety of disease states and provided clinical information not available from any other non-invasive technique.

Adult↗