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Biomedical subjects

S M Hall

Publications and source records attributed to S M Hall.

At least 181 records · Page 10Linked to original sources
PubMed1984

Effect of high-frequency oscillation on blood flow to an atelectatic lung in closed-chest dogs.

Seven dogs with electromagnetic flow probes implanted on their main (QT) and left (QL) pulmonary arteries, had catheters placed in their left atria and pulmonary artery, and were ventilated via Carlen's double-lumen endotracheal tubes. The effect of high-frequency oscillation (HFO) on the redistribution of pulmonary blood flow away from unilaterally atelectatic lungs was determined. During bilateral ventilation with 100% O2, using either a Harvard respirator (PPV) or an Emerson airway vibrator (HFO), the fraction of cardiac output perfusing the left lung (QL/QT) was 0.45 +/- .01 and 0.43 +/- .01, respectively, whereas PaO2 was 465 +/- 40 and 334 +/- 34 torr, respectively. With left lung atelectasis during right lung ventilation with PPV at 10 to 15 cycle/min, QL/QT fell to 0.37 +/- .01 and PaO2 was 56 +/- 5 torr. During HFO at 100 cycle/min, QL/QT fell to 0.32 +/- .02 whereas PaO2 rose to 102 +/- 23 torr. Mean transpulmonary pressure was 10.0 +/- 1.5 torr with PPV and 7.3 +/- 1.2 torr during HFO; intrapleural pressures were -3.2 +/- 1.6 and -5.7 +/- 1.4 mm Hg, respectively. Thus, the diversion of blood away from unilaterally atelectatic lungs was better maintained during HFO.

Animals↗
PubMed1984

Computer-controlled anesthetic delivery system.

We designed and tested a computer-controlled syringe pump for the administration of volatile anesthetics into a closed breathing circuit. The system consists of a small computer, a flip-flop circuit, and an automatic syringe pump. The computer was programmed to administer liquid anesthetics according to the square root of time model of anesthetic uptake. A simple electronic flip-flop circuit connected the computer to the syringe pump. Safeguards to prevent accidental anesthetic overdosage and algorithms to provide for dosage changes based on patient response were written into the program. After testing, the system was used to administer anesthetics to ten patients undergoing surgical procedures. The anesthetic uptake deviated from the square root of time model after approximately two hours. The system provided smooth and reliable administration of volatile anesthetics during closed circuit anesthesia.

Adult↗
PubMed1984

Detection of serum antibody to Brucella abortus in cattle by use of a quantitative fluorometric immunoassay.

A quantitative fluorometric immunoassay (FIAX) was adapted for the detection of serum antibodies to Brucella abortus in cattle. Results are expressed in nanograms of immunoglobulin binding the antigen carrier. The FIAX was compared with the standard tube agglutination, Rivanol precipitation, and complement fixation tests, using 285 serum samples from vaccinated, challenged, or control cattle. Linear regression analysis indicated a significant correlation among all four serological tests; the FIAX test correlated best with the Rivanol test. Ninety sera were from vaccinated and nonvaccinated cattle that were challenged with virulent B. abortus 2308. The sensitivity and specificity of each serological test were determined based on culture results from these cattle. The FIAX was the most sensitive of the four serological tests, detecting 79.2% of the culture-positive animals. The FIAX was the least specific, with 15.4% of the culture-negative animals being classified as positive. Eighty-eight sera were from cattle vaccinated with strain 19 but not challenged. All four serological tests had a statistically significant ability to distinguish sera from control and vaccinates on the basis of mean titers. The mean titer of vaccinates was also significantly different from that of challenged animals. Advantages and disadvantages of the FIAX test for bovine brucellosis are discussed.

Animals↗
PubMed1984

The abstinence phobias: links between substance abuse and anxiety.

This paper presents a new model to explain the observed relationship between anxiety and substance abuse. Specifically, the concept of "abstinence phobias," common across psychoactive substances, is developed. The evidence needed to support this concept is outlined, and relevant data from studies of opiate, alcohol, and tobacco dependences are reviewed. Parallel data obtained from the treatment of obesity are discussed. It is concluded that the abstinence phobia merits further study; clinical implications are also considered.

Alcohol Withdrawal Delirium↗
PubMed1983

Congenital toxoplasmosis in England, Wales, and Northern Ireland: some epidemiological problems.

It has been suggested that congenital toxoplasmosis could be prevented by antenatal serological screening, followed by treatment or by termination of pregnancy if infection occurs. The only study of the incidence of congenital toxoplasmosis in England, Wales, and Northern Ireland took place more than 10 years ago. To obtain more recent figures laboratory reports of cases occurring from 1975 to 1980 were analysed. A total of 91 cases were reported over the six years. By criteria established to classify these infections only 34 were congenital, 20 were acquired postnatally, and 37 were unclassifiable. The mean annual number of cases of congenital toxoplasmosis was considerably smaller than that found in other recent studies. The condition could be underdiagnosed or rates of placental transmission could be lower in Britain than in other countries. Variation in reporting criteria of the laboratories made the data difficult to interpret. Improved diagnosis of congenital toxoplasmosis would not only clarify the epidemiology but would also help clinicians in management of suspected cases. Further antenatal surveys are necessary to assess the role of screening in the prevention of congenital toxoplasmosis.

Child, Preschool↗
PubMed1983

Smokers of low-yield cigarettes do not consume less nicotine.

Advertisements suggest that smokers of cigarettes low in nicotine are exposed to less nicotine and tar. Nicotine yields are measured with smoking machines, but machines do not smoke cigarettes as people do. We therefore measured the actual nicotine content of commercial cigarettes with different nicotine and tar yields as determined with smoking machines, and also measured actual nicotine intake as indicated by blood concentrations of its metabolite, cotinine, in 272 subjects smoking various brands of cigarettes. We found that low-yield cigarette tobacco did not contain less nicotine; in fact, the nicotine concentration in tobacco inversely correlated (r = -0.53, P less than 0.05) with the concentration measured by smoking machines. Blood cotinine concentrations correlated with the number of cigarettes smoked per day but not with the nicotine yield measured by smoking machines. Only 3.8 to 5.0 per cent of total variance in blood cotinine was contributed by nicotine yield. We conclude that smokers of low-nicotine cigarettes do not consume less nicotine.

Adult↗
PubMed1983

Cranial nerve palsies in metastatic breast cancer due to osseous metastasis without intracranial involvement.

Between August 1972 and March 1981, ten patients with metastatic breast cancer presented to M.D. Anderson Hospital and Tumor Institute at Houston Medical Breast Clinic with cranial nerve palsies (incidence, 0.13%). Eight of ten patients had extensive metastases at the base of the skull that was causing cranial nerve compression. Two patients had no bone involvement and were suspected to have soft tissue disease, one retro-orbitally and the other at the base of the skull. None of the patients had evidence of intracranial disease. The most frequently affected cranial nerves were V and VII, with 70% and 60% of patients having palsies of these nerves respectively. The estimated median survival of the patients from time of onset of cranial nerve palsy was 20 months; the palsies improved in 50% of patients who received regional therapy.

Adult↗
PubMed1983

The response of the (myelinating) Schwann cell population to multiple episodes of demyelination.

The effects of multiple intraneural injections of the known demyelinating agent lysophosphatidyl choline, LPC, have been studied in the sciatic nerves of adult mice. Up to six separate episodes of demyelination were induced at the same site within the tibial fascicle. Demyelination and subsequent remyelination occurred after each injection. The number of Schwann cells produced during each repair programme exceeded the number required for remyelination and some of the surplus cells temporarily remained associated with the remyelinating axon/Schwann cell units as supernumerary Schwann cells. There was a progressive decline in the proportion of promyelinated axons as the number of injections of LPC increased. The proposition that this could have reflected a more rapid repair following demyelination of thinly (re)myelinated axons was investigated in double LPC-injected nerves. No structures resembling onion bulbs characteristic of hypertrophic neuropathies in man were seen during the course of this study.

Animals↗
PubMed1983

Smoking cessation in patients with cardiopulmonary disease: an initial study.

Thirty-five smokers, all with current, long-standing, cardiovascular or pulmonary disease, were randomly assigned to either health motivation treatment, or to aversive smoking. The former included self-management skills, a film model, verbal commitment, and discussion of the costs and benefits of smoking and abstinence. The latter included normally paced (every 30 sec.) aversive smoking, relaxation training, role playing high risk situations, and discussion of maladaptive thought patterns. Strong differences between the conditions in abstinence rate and reduction from baseline did not emerge; however, the data generally favored the health motivation condition both in attrition rates and in outcome immediately posttreatment and at six month follow-up. Negative mood states were found to be related to minimal reduction in smoking; and consistent mood dysphoria at pre and posttreatment predicted relapse at three month follow-up.

Affect↗
PubMed1983

Oxaprozin and sulindac in rheumatoid arthritis: a double-blind comparative trial.

Oxaprozin, an anti-inflammatory agent with a half-life of 50 hours, was compared in regard to efficacy and tolerance with sulindac in a 12-week double-blind parallel treatment trial of rheumatoid arthritis. Oxaprozin was given as a single morning daily dose of 1200 mg, sulindac was given as 200 mg twice daily. Analysis of the results from the 20 patients (10 in each group) who completed the trial indicated that both drugs produced statistically significant improvement in morning stiffness, walking speed and the Ritchie index, but only sulindac produced significant improvement in hand function. Neither drug was associated with significant side-effects.

Adult↗