Two-mass model of the vocal folds: negative differential resistance oscillation.

The vocal folds and glottis are analyzed as a single system rather than as two separate but interacting systems, i.e., an aerodynamic one (the glottis) and a mechanical one (the vocal folds).

The effects of conjugated equine estrogens plus cyclical dydrogesterone on serum lipoproteins and apoproteins in postmenopausal women.

Serum lipoprotein and apoprotein concentrations were monitored for 24 weeks in 26 postmenopausal women treated with conjugated equine estrogens (0.625 mg/day) with the addition of dydrogesterone (10 mg/day) for the last 12 days of each 28 day cycle. The women had had no previous hormone replacement therapy.

Purification and characterization of a novel extracellular esterase from pathogenic Streptomyces scabies that is inducible by zinc.

Native polyacrylamide gels of extracellular proteins produced by several Streptomyces isolates grown with suberin were assayed in situ for esterase activity. Two pathogenic isolates of Streptomyces scabies from different geographical regions were found to produce a similar esterase activity that was not produced by nonpathogenic strains. After treatment with EDTA, suberin no longer induced esterase production.

A research programme in lifestyle and health: methodological and theoretical considerations.

Traditionally, research in health behaviour has been dominated by research ideologies and methods which developed in the health sciences and the social sciences. To a great extent these subjects have followed "classical" research designs propounded by the natural sciences. The result has been a marked dependency on survey research, quasi-experimental designs, case-control studies and other "static" designs.

Polyarticular pigmented villonodular synovitis in children: evidence for a genetic contribution.

Pigmented villonodular synovitis rarely occurs in multiple joints, and only once has been noted in siblings. We identified this disorder in 2 generations and found evidence for its presence in a third. It occurred in 2 sibling children at multiple sites.

Characterization of opioid receptors in the cat carotid body involved in chemosensory depression in vivo.

The effects of selective opioid receptor agonists and antagonists on neural discharge recorded from carotid body arterial chemoreceptors in vivo were studied in anaesthetized cats. Mean ID50 values were determined for each agonist and used to assess chemodepressant potency on intracarotid (i.c.

Pharmacological characterization of the receptor involved in chemoexcitation induced by adenosine.

Experiments were performed on cats anaesthetized with pentobarbitone in which carotid body chemoreceptor activity was recorded from the peripheral end of a sectioned carotid nerve. Intracarotid (i.c.

Computer corner #13. Computerized examinations in orthopaedics.

Computerized examinations can play an important role in the evaluation and education of trainees in orthopaedics. Several centers in the United States and Canada are currently using these, thus allowing an exchange of examination questions. Once a system is set up, only minimal involvement on the part of the instructor and office staff is required.

Effects of timing of atrial systole on LV filling and mitral valve closure: computer and dog studies.

Atrioventricular (AV) delay that results in maximum ventricular filling and physiological mechanisms that govern dependence of filling on timing of atrial systole were studied by combining computer experiments with experiments in the anesthetized dog instrumented to measure phasic mitral flow. Ventricular filling volume is maximized at AV delay of 100 ms in the computer study and 80 ms in the dog study. At any time in diastole atrial contraction accelerates mitral flow, opening the mitral valve widely; atrial relaxation then decelerates mitral flow, moving the valve leaflets toward closure.

Computer-assisted design of butterfly bileaflet valves for the mitral position.

This paper describes the application of computer testing to a design study of butterfly bileaflet mitral prostheses having flat or curved leaflets. The curvature is in the plane normal to the pivot axes and is such that the convex sides of the leaflets face each other when the valve is open. The design parameters considered are the curvature of the leaflets and the location of the pivot points.

China's impact on American medicine in the seventies: a limited and preliminary inquiry.

A citation survey of the impact of Chinese medical ideas on Western medical literature is presented. In general it is argued that the diffusion of ideas was very rapid at the beginning of the decade, but has markedly slowed recently. Speculations on this 'loss of interest' are offered.

Changes in carotid body amine levels and effects of dopamine on respiration in rats treated neonatally with capsaicin.

Dopamine levels in rat carotid bodies and the effects of intravenous dopamine injections on respiration in adult rats anaesthetized with pentobarbitone have been studied in animals which were treated with capsaicin neonatally. Levels of dopamine were five fold higher in the carotid bodies of capsaicin-treated rats as compared with vehicle-treated controls, but there was no significant difference between capsaicin-treated and vehicle-treated rats in their ID50 values for dopamine-induced respiratory depression. Domperidone, a dopamine D2-receptor antagonist, substantially reduced the respiratory depression caused by dopamine, both in capsaicin-treated and in control animals, suggesting that a D2-receptor was involved in the response.

Increased sensitivity of rabbit carotid body chemoreceptors to dopamine after chronic treatment with domperidone.

An increase in specific dopamine D2 receptor binding sites was observed in membranes prepared from the carotid bodies of rabbits treated for 8 weeks and then withdrawn for 4-9 days from the D2 antagonist domperidone (2-5 mg/kg per day). Recordings of chemoreceptor afferent discharge from the carotid body also revealed that this change in receptor density was accompanied by an increased sensitivity to the chemodepressant effects of exogenous dopamine. The chemoreceptor responsiveness of the carotid body to hypoxia is blunted in rabbits treated chronically with domperidone, but this can be restored to normal by an acute dose of the D2 antagonist.

Effects of the antagonists MDL 72222 and ketanserin on responses of cat carotid body chemoreceptors to 5-hydroxytryptamine.

The effects of intracarotid (i.c.) injections of 5-hydroxytryptamine (5-HT; 1-50 micrograms) on carotid chemoreceptor activity recorded from the carotid sinus nerve have been studied in anaesthetized cats.

Alcohol consumption patterns among women in Baltimore.

A telephone survey of women aged 18 + (N = 1084) in Baltimore during 1980 showed that 8.1% had a heavy alcohol intake (2 + drinks per day) and that 22.4% engaged in escape drinking.

Optothermal measurement of haemoglobin in blood.

A prototype instrument based on optothermal spectroscopy has been developed for determining the haemoglobin content of blood. The optothermal detector is described and consists essentially of a thin sapphire disc glued to a piezoelectric ring. The optothermal instrument is also described.

Direct biochemical and neuropharmacological identification of dopamine D2-receptors in the rabbit carotid body.

Dopamine D2-receptors were directly identified in receptor binding assays with washed particulate preparations of rabbit carotid body using the selective ligand, [3H]domperidone. High affinity, saturable specific binding of [3H]domperidone was clearly demonstrable and chronic section of the sinus nerve resulted in a 32% decrease in the labelling of the dopamine D2-sites. Adenylate cyclase activity was also detected in rabbit carotid body homogenates and although this enzyme was stimulated 4-fold by 10 mM sodium fluoride, neither dopamine nor isoprenaline significantly altered basal activity.

Detection and treatment of emotionally disturbed children in public schools: problems and theoretical perspectives.

Examined the effect of selected socio-demographic, mental health resource, and school system variables on the identification and treatment of children as emotionally disturbed. An explanatory model is provided, and the Labeling and Social Movements perspectives are examined in terms of their explanatory power. The major finding is that emotionally disturbed children are significantly underdetected and underserved nationally in public school systems, and, specifically, in Maryland and Washington, D.

On the specificity and type of receptor involved in carotid body chemoreceptor activation by adenosine in the cat.

Experiments were performed on cats anaesthetized with pentobarbitone in which carotid chemoreceptor activity was recorded from the peripheral end of a sectioned carotid sinus nerve. Intracarotid injections of adenosine 5'-triphosphate (ATP) (1-100 micrograms i.c.

Computer-assisted design of pivoting disc prosthetic mitral valves.

This paper describes the use of the new technique of computer testing to study the simulated performance of flat and curved pivoting disc prosthetic mitral valves. The design parameters considered are the radius of curvature of the occluder and the position of the pivot point. The performance criteria are the net stroke volume, the mean forward pressure difference, and the peak anterior velocity.

Effects of ouabain on carotid body chemoreceptor activity in the cat.

The effects of infusions of ouabain on chemoreceptor activity recorded from the peripheral end of a sectioned carotid sinus nerve were studied in cats anaesthetized with pentobarbitone. Ouabain caused a marked increase in chemoreceptor discharge followed by a decline in discharge to frequencies near or below the pre-ouabain level; during the latter period further administration of ouabain had no effect. Infusion of ouabain during hypoxia further increased the chemoreceptor discharge, but this effect was short-lasting.