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Biomedical subjects

D Davis

Publications and source records attributed to D Davis.

At least 253 records · Page 14Linked to original sources

Subclavian venous stenosis. A complication of subclavian dialysis.

Subclavian hemodialysis catheters are widely employed for temporary hemodialysis access, but there are few reports of serious complications. We report three cases in which the prolonged (greater than 15 days) use of subclavian dialysis catheters ipsilateral to the permanent vascular access was associated with the development of subclavian vein (SCV) stenosis three to six months after the temporary catheter was removed. In one case, the use of the permanent access was severely limited by massive arm edema. We conclude that, in addition to the usual complications of SCV cannulation, long-term use of SCV hemodialysis catheters can be associated with major late obstructive complications that may compromise permanent vascular access. We recommend that, wherever possible, temporary dialysis catheters and other subclavian lines be placed contralateral to the permanent vascular access site in patients undergoing hemodialysis.

Aged↗

Infection with Dermatophilus congolensis at a contact hypersensitivity site and its relevance to chronic streptothricosis lesions in the cattle of West Africa.

Guinea-pigs were sensitized to CDNB and infected with D. congolensis at the site of a subsequent application of this chemical. The bacterium was recovered from the skin over a longer period of time in sensitized individuals than in nonsensitized controls. Animals rendered tolerant to the chemical gave lower yields of bacteria than sensitized animals. However, the lesions produced at the site of infection did not become chronic. The growth of D. congolensis at a contact hypersensitivity site may possibly simulate infection in skin following an arthropod bite and be relevant to the pathogenesis of chronic streptothricosis lesions in the cattle of West Africa.

Actinomycetales↗

Effects of nadolol and propranolol on plasma lidocaine clearance.

Nadolol and propranolol effects on lidocaine elimination were followed in six healthy men and women. Each received three separate 30-hr infusions of lidocaine (2 mg/min): one alone, one after 3 days pretreatment with nadolol (160 mg daily), and one after 3 days pretreatment with propranolol (80 mg every 8 hr). Liver blood flow was determined by the systemic clearance of indocyanine green. Steady-state plasma lidocaine levels were increased by nadolol (2.1 +/- 0.2 to 2.7 +/- 0.3 micrograms/ml) and by propranolol (2.1 +/- 0.2 to 2.5 +/- 0.3 micrograms/ml). Lidocaine plasma clearance was decreased by nadolol (1030 +/- 81 to 850 +/- 82 ml/min) and by propranolol (1030 +/- 81 to 866 +/- 75 ml/min). Hepatic blood flow was decreased by nadolol (1275 +/- 77 to 902 +/- 102 ml/min) and propranolol (1275 +/- 77 to 957 +/- 119 ml/min). The hepatic extraction ratio for lidocaine was increased by nadolol (0.86 +/- 0.06 to 0.91 +/- 0.05) and by propranolol (0.86 +/- 0.06 to 0.90 +/- 0.06). Lidocaine intrinsic clearance was not changed by nadolol (8.19 +/- 1.87 to 9.52 +/- 2.36 l/min) or propranolol (8.19 +/- 1.87 to 9.50 +/- 3.13 l/min). Our data indicate that both nadolol and propranolol reduce lidocaine clearance by their effects on hepatic blood flow and not by inhibition of lidocaine metabolism.

Adult↗

Isolation and Characterization of Swainsonine from Texas Locoweed (Astragalus emoryanus).

Swainsonine (1,2,8-trihydroxyoctahydroindolizine) was isolated from locoweed (Astragalus emoryanus) that grows in Texas. Using a biological assay as a measure of activity and purity, a relatively straightforward purification of the compound is described. The purified material was a potent inhibitor of jack bean alpha-mannosidase and also of glycoprotein processing. The positive ion electron impact mass spectra of this compound was identical to that of authentic swainsonine. Nuclear magnetic resonance analysis also confirmed that the material was swainsonine.

Journal Article↗

Enzyme immunoassay for detection of pneumococcal antigen in cerebrospinal fluid.

A solid-phase immunoassay utilizing horse antiserum against the C polysaccharide of Streptococcus pneumoniae and biotinylated rabbit antibodies to type-specific pneumococcal polysaccharides was developed to detect pneumococcal antigens in human body fluids and in broth cultures. Pneumococcal antigen could be detected in broth cultures of serotypes of S. pneumoniae containing as little as 10(2) to 10(3) organisms per ml. The assay system detected pneumococcal antigen in all 25 cerebrospinal fluid specimens obtained from patients with documented pneumococcal meningitis. There were no positive reactions noted in specimens from patients infected with Neisseria meningitidis group A or from patients without evidence of bacterial infection. The solid-phase enzyme immunoassay utilizing these reagents is a sensitive and specific assay for the immunodetection of a wide range of pneumococcal antigens.

Adult↗

Disinfection of the flexible fibreoptic bronchoscope against Mycobacterium tuberculosis and M gordonae.

In view of recent reports of contamination of the fibreoptic bronchoscope by tuberculous and non-tuberculous mycobacteria, we evaluated the disinfecting properties of aqueous glutaraldehyde (Cidex) and an iodophor (Prepodyne) against Mycobacterium tuberculosis and M gordonae. We found that a 15 minute disinfection procedure with either agent, coupled with initial vigorous mechanical cleaning of the bronchoscope and its accessories, is a quick and reliable method for preventing the contamination of the bronchoscope with mycobacteria.

Bronchoscopy↗

Familial congenital short small bowel with associated defects. A long-term survival.

In 1974, Royer et al. described a familial syndrome consisting of a short and sluggish small bowel, malrotation of the gut, and pyloric stenosis. These authors stressed the uniformly fatal outcome of their four cases, as well as other possibly unrecognized cases previously described in the literature. The present report deals with two more familial cases, of which one represents a long-term survivor of the syndrome. The intensive work of maintaining nutrition, controlling infection, and managing the complications of associated defects are described.

Abnormalities, Multiple↗

Cataract formation following limited amino acid intake during gestation and lactation.

Female rats were fed defined diets limiting in one or more of certain amino acids and with or without vitamin E throughout gestation and lactation. Deficits of tryptophan, phenylalanine/tyrosine, or methionine/cystine reduced the body weight of progeny to about 50% or less of normal but only low tryptophan was cataractogenic. When total dietary amino acids were 12.4%, a low (65 mg%) level of tryptophan resulted in 34% incidence of cataract if vitamin E was simultaneously withheld. Elevation of total amino acids to 24.8% while maintaining tryptophan at 65 mg% caused 70 or 90% incidence of nuclear lens opacities in the presence or absence, respectively, of vitamin E. Maternal dietary amino acid imbalance was also associated with a 50% decrease in lens insoluble (membrane) proteins in the progeny independent of dietary vitamin E or the occurrence of opacities.

Amino Acids↗

An in vivo method of assay for Dermatophilus congolensis.

An in vivo method of assay for Dermatophitus congolensis in rats is described. The optimal conditions for preparing skin before infection and subsequently harvesting the zoospores from infected skin were investigated. These experiments showed that clipping the skin had no effect on infection with this bacterium and that when the infected skin was soaked in water, increased amounts of dissolved CO2 had no effect on the release of zoospores, which was maximal within 2.5 h of immersion. Vaccination studies demonstrated that this assay gave results comparable to previously published data, where these data were quantitative. Infection with D. congolensis was not related to the production of exudate on the skin surface. This is the first report that D. congolensis can infect skin without producing an exudate. Hypotheses linking skin damage and susceptibility to infection with this bacterium are discussed in the light of this observation.

Actinomyces↗

CSF 5HIAA and personal and family history of suicide in affectively ill patients: a negative study.

Personal and family histories of suicidality were gathered in 45 patients who met Research Diagnostic Criteria for major affective disorder (n = 32, bipolar; n = 13, unipolar) and compared to CSF values of 5HIAA obtained by two different assays (n = 20, fluorometric; n = 25, high performance liquid chromatography). In separate analyses of the two assay groups, patients who had made a suicide attempt were not significantly different from those who had not in terms of 5HIAA value or family history of suicidality. Furthermore, in suicide attempters, 5HIAA was unrelated to the severity of the attempt.

Adult↗

Diagnosis and management of myocardial ischemia in the postoperative period.

The determinants of myocardial oxygen consumption, the consequences of coronary artery atherosclerosis, angina, and myocardial infarction, and their therapy are considered in this article. The mechanism of action of the drugs used in the therapy of myocardial ischemia and the rationale for their use is discussed. A plan of in-hospital rehabilitation for the postoperative myocardial infarction patient is also offered.

Angina Pectoris↗

Diagnosis and management of cardiac arrhythmias in the postoperative period.

Various rhythm disturbances occur in the postoperative patient. Proper management requires an awareness of clinical circumstances in which they are most likely to happen. Often, the appearance of new arrhythmias in the postoperative period is a manifestation of underlying remediable medical problems. Direct antiarrhythmic therapy is unnecessary in many patients when these precipitating conditions are properly treated.

Arrhythmias, Cardiac↗

Pacemakers in noncardiac surgery.

The authors look at the use of pacemakers in three groups of patients: one with previously implanted cardiac pacemakers, one requiring temporary pacing systems for reasons related to their heart, and one in whom indications exist for permanent pacemaker implantation, but because of a surgical emergency, cannot have a permanent unit implanted before the noncardiac operation.

Arrhythmias, Cardiac↗