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Biomedical subjects

A S Johnson

Publications and source records attributed to A S Johnson.

34 records · Page 2Linked to original sources
PubMed1995

Cardiovascular response to acute and chronic endotoxemia in an awake, volume-resuscitated, canine model.

The cardiovascular response to endotoxemia was evaluated in an awake, intravascular volume-resuscitated canine model. The animals were chronically instrumented for ultrasonic crystal dimension analysis and pressure measurements of the left ventricle (LV), aorta, right atrium (RA), and pulmonary artery (PA) and for cardiac output (CO) measurement. Lipopolysaccharide (Escherichia coli 011:B4) (LPS) was administered intravenously either as an acute, high dose bolus (5 mg/kg; n = 5), a high dose bolus after complete beta-blockade with propranolol (n = 3), or a chronic, low dose infusion (5 micrograms/kg/h; n = 7). Relative to baseline values, cardiac contractility was increased after acute high dose LPS bolus, however this effect was negated by beta-blockade. Chronic, low dose LPS infusion produced an increase in cardiac contractility at 1 h, a return to baseline by 4 h, and maximal contractile depression by 24 h. No change was seen in LV compliance after the high dose LPS bolus. The LV end diastolic volume was decreased by the high dose LPS bolus. This change was blocked by propranolol administration. Chronic LPS administration was accompanied by a decrease in LV compliance and an increase in LV end diastolic volume. Other cardiovascular indices (heart rate, CO, systemic vascular resistance) changed in a fashion similar to human sepsis. These findings confirm that endotoxemia in conscious canine subjects causes changes in cardiovascular function similar to that seen in human and animal models of sepsis. This study also allows us to explain some of the discrepancies between earlier studies of human sepsis and animal models in which the appropriate clinical conditions and an intact neuro-endocrine axis were not maintained.

Animals↗
PubMed1995

Palliative care in the home?

Finally, in conclusion, I return to the question: Palliative care at home? Indeed, it is an option, one that more and more PLWH/As are choosing. And to some extent, the choice to die at home is a testimony to the significant progress we have made in our ability and commitment to provide palliative care at home. The challenge before us is to find solutions to the problem when the option to die at home, based on existing services, is not viable. As is the case with every aspect of care along the HIV continuum, the difficulties we encounter in AIDS palliative care should be viewed as opportunities to expand our understanding of the HIV illness experience; the meaning of quality of life from the consumer's perspective and how it can be achieved and maintained; and how we as health professionals can work together in teams that honor and support the role of families, social networks, and community-based AIDS service organizations involved in AIDS palliative care. Despite the trend to shift part of our focus from institutional to community settings of care, we must never lose sight of the fact that when we enter the homes of our clients, regardless of our role, we are guests. And it is in that role that we must, when necessary, put aside our loyalty to traditional approaches to care and open our hearts and minds to the direction and needs of those who choose to die at home with AIDS.

Acquired Immunodeficiency Syndrome↗
PubMed1993

Acipimox increases glucose disposal in normal man independent of changes in plasma nonesterified fatty acid concentration and whole-body lipid oxidation rate.

The short-term administration of a nicotinic acid analogue (acipimox) increases insulin sensitivity and consequently glucose disposal, both in patients with non-insulin-dependent diabetes mellitus (NIDDM) and in patients with cirrhosis. This effect has been attributed to a decrease in plasma nonesterified fatty acid (NEFA) levels and fatty acid oxidation rates, and a corresponding increase in carbohydrate oxidation. The aim of the present study was to determine whether acipimox influenced glucose disposal independent of changes in lipid metabolism. Seven normal men (age, 31 +/- 4 years; body mass index, 23.2 +/- 1.8 kg.m-2; fat-free mass [FFM], 66.8 +/- 4.2 kg) were studied on two separate occasions with hyperinsulinemic (0.06 U.kg FFM-1.h-1) euglycemic clamps (duration, 150 minutes). A primed (150 U), continuous (0.4 U.kg-1.min-1) infusion of heparin together with 10% intralipid (25 mL.h-1) was infused in both studies from -90 to 150 minutes to maintain comparable levels of plasma NEFA and lipid oxidation rates. Acipimox (500-mg capsules) or placebo were administered orally in a double-blind random fashion at t = -90 and t = 0 minutes. Whole-body lipid and carbohydrate oxidation were measured in the last 30 minutes of both the basal (preclamp) period (-30 to 0 minutes) and the clamp period (120 to 150 minutes).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Cutaneous infection with Rhizopus oryzae and Aspergillus niger following bone marrow transplantation.

We describe a case of mixed Rhizopus oryzae and Aspergillus niger infection in a 38 year-old woman who had undergone allogeneic bone marrow transplantation for multiple myeloma. The fungi were isolated from a necrotic ulcer under a plaster cast stabilizing a pathological fracture of the left humerus. We emphasize the necessity for frequent inspection of any covered area of skin and the use of sterile dressings as far as possible in neutropenic patients.

Adult↗
PubMed1993

The role of endoscopic retrograde cholangiopancreatography: sphincterotomy versus common bile duct exploration as a primary technique in the management of choledocholithiasis.

253 patients underwent diagnostic or therapeutic intervention for a presumed diagnosis of choledocholithiasis. In 104 (mean age, 60 years) the diagnosis was confirmed by endoscopic retrograde cholangiopancreatography (ERCP) or common bile duct exploration (CBDE). Of this group, 70 patients first underwent a total of 102 attempts at endoscopic sphincterotomy (ERCP-S). Success (clearing the common duct of stones) was achieved in 43 patients (61%), though an average of 1.5 ERCP-S/patient was required (maximum of four per patient). Of the 27 in whom ERCP-S failed, 20 went on to CBDE, which was successful in 18. Significant morbidity occurred in 12 (17%) ERCP-S patients, including hemorrhage. There were no deaths. Of the 34 patients who first underwent CBDE, 30 were cleared of common duct stones (88%). ERCP-S was subsequently employed to retrieve retained stones in three patients. Significant morbidity was documented in three (9%). No patients required perioperative blood transfusion. There were no deaths. While there is, as expected, a lower initial success rate with ERCP-S than with CBDE, the fact that ERCP-S is a less invasive procedure than is CBDE justifies its preferential utilization. However, patients must be informed that successful ERCP-S may require multiple visits to the endoscopy suite. Furthermore, the morbid consequences of ERCP-S, particularly hemorrhage, cannot be understated.

Cholangiopancreatography, Endoscopic Retrograde↗
PubMed1990

The role of hydrophobicity and electronic factors in regulating alcohol inhibition of cytochrome P-450-mediated aniline hydroxylation.

The role of hydrophobicity and electronic factors in regulating alcohol inhibition of cytochrome P-450-mediated aniline p-hydroxylation has been investigated by the formulation of quantitative structure-activity relationships. The activity of linear primary alcohols and unhindered linear secondary alcohols shows a linear dependence on log P, where P is the octanol-water partition coefficient. Hindered primary and secondary alcohols are less active than this relationship predicts. An equation describing the activity of both hindered and unhindered primary and secondary alcohols shows that alcohol inhibition of aniline hydroxylation is regulated by hydrophobicity and steric effects. No role for electronic factors can be discerned. Similarities are found between alcohol inhibition and the binding of alkyl amines to cytochrome P-450, suggesting that alcohols may bind to the amine binding site.

Alcohols↗
PubMed1990

Prevalence of eating disorders in the psychiatric emergency room.

A random sample of 143 patients from a centralized psychiatric emergency service with a catchment area of one million people was studied. A two-stage interview was conducted for diagnosis of DSM-III-R eating disorders. Of those reporting active bingeing, 14.5% were men, and 22.4% were women. No cases of anorexia nervosa were discovered. Bulimia nervosa was diagnosed in 3.0% of the women and 2.6% of the men. Race and marital status were unrelated to bingeing or to any eating disorder diagnosis. Many patients never had discussed their eating behaviors before with a therapist.

Adolescent↗
PubMed1989

Pattern of caries experience in permanent molars in a 15-year-old African population.

Some epidemiologic studies from Africa report higher DMF values in second than in first molars. It is generally accepted that the maturation of dental enamel influences the susceptibility of teeth to caries. The purpose of the present study was to test the hypothesis that DMF values of second molars will be higher than those of first molars if the first molars have reached a high degree of maturation before being exposed to increased cariogenic challenge. The study was carried out in a group of 15-year-old students attending secondary schools in Botswana (n = 287). The results showed that in children who assumingly had had a traditional diet during childhood the DMF values were higher in second molars than in first molars. In children who grew up in a more urbanized setting, the results were opposite. The observed differences were due to differences in caries experience in first molars only. The DMF values of second molars did not vary among the groups. Oral hygiene, sugar consumption and knowledge level at age 15 seemed to have no effect upon the caries pattern studied. It is concluded that the results support the hypothesis tested.

Adolescent↗
PubMed1986

A method for reducing the noise generated in digitizing or analog recording of EEG data.

Magnetic recording and/or analog-to-digital conversion add noise to the data. This paper describes a method for reducing the noise added to EEG data by recording and digitizing. A linear filter is described which pre-emphasizes the EEG before recording or digitizing; a second filter then recovers the original signal after playback. The technique can result in a factor of 10 (20 dB) improvement of the signal-to-noise ratio of high frequency EEG components.

Analog-Digital Conversion↗