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Biomedical subjects

J Johnson

Publications and source records attributed to J Johnson.

At least 487 records · Page 27Linked to original sources
PubMed1988

Attempted suicide in youth: its relationship to school achievement, educational goals, and socioeconomic status.

Twenty-six suicide attempters, 9 to 18 years of age, were compared with 725 nonattempters on measures of school achievement, educational goals, socioeconomic status, and depression. As has been found in studies using clinical samples, suicide attempters in our community-based sample had significantly lower school achievement than nonattempters. The relationship between attempted suicide and low school achievement seemed to be explained by the effects of depression. Lower-SES youth tended to be more likely to attempt suicide than higher-SES youths. However, SES appeared to have little effect on the relationship between attempted suicide and school achievement. Results also suggest that children of mothers with low educational goals for them may be more at risk for attempted suicide than youths whose mothers have higher educational goals for their children.

Achievement↗
PubMed1988

Scintigraphic detection of regional disruption of adrenergic neurons in the heart.

Experiments were designed to detect regional disruptions of adrenergic neurons in the hearts of living dogs. The neuron disruption was achieved by the application of phenol to the epicardium of the left ventricle. Evidence for denervation was the reduction in endogenous norepinephrine (NE) concentrations in the myocardium beneath the region of phenol treatment and toward the apex. Radiolabeled meta-iodobenzylguanidine (MIBG) acts as an analog of NE and as such is concentrated in adrenergic nerve terminals. Following phenol application, MIBG labeled with 125I was found, 20 hours after injection, to be distributed within myocardium in patterns comparable to those of NE. However, left stellectomy did not alter the distributions of NE or 125I-MIBG in the myocardium and apparently did not disrupt adrenergic innervation. MIBG labeled with 123I enabled scintigraphic images of heart neurons in the living dog 3 and 20 hours after injection; these images portrayed the regions of adrenergic neuron disruption caused by phenol treatment. Concentrations of thallium-201 depicted on scintigraphic image and of triphenyltetrazolium observed on in vitro staining demonstrated no myocardial injury. Thus scintigraphy with 123I-MIBG will display regional adrenergic denervations in the heart.

3-Iodobenzylguanidine↗
PubMed1988

Evaluation of a simple method for measuring blood cholesterol levels using non-laboratory observers.

PURPOSE: Blood cholesterol is a good estimator of risk for coronary heart disease. Six criteria for a screening cholesterol measurement are: (1) high predictive value of elevated cholesterol compared with a "gold standard" cholesterol measurement; (2) high correlation with the national reference system for cholesterol; (3) acceptable results obtainable by volunteer observers; (4) results available quickly; (5) reproducible results; and (6) low cost. We hypothesized that cholesterol measurements performed on the Reflotron by volunteer nurses would meet these criteria. SUBJECTS AND METHODS: We recruited 345 subjects (160 men, 185 women, aged 20 to 84) and measured their blood cholesterol level by a method calibrated under the National Heart, Lung, and Blood Institute Lipid Standardization Program (Lab-chol) and on the Reflotron (R-chol method). RESULTS: Comparison of the results showed good agreement (slope = 0.937; intercept = 0.27 mmol/liter). Comparison of the risk assignments made by the R-chol method against those made by the Lab-chol method, using the 1987 Adult Treatment Panel classification criteria, showed that the R-chol method has a sensitivity of 0.79 and a specificity of 0.98. Assuming a national prevalence of hypercholesterolemia of 25 percent, the positive predictive value is 0.92 and the negative predictive value is 0.93. The cost per screen was $1.25. CONCLUSION: These data show that volunteer observers can obtain screening cholesterol results on the Reflotron that are accurate, reliable, quickly available at a low cost, and have high predictive value for hypercholesterolemia.

Adult↗
PubMed1988

Level of knowledge among adolescent girls regarding effective treatment for dysmenorrhea.

Are adolescent women aware of the relatively specific pharmacologic intervention now available for dysmenorrhea? A multiple-choice questionnaire was administered to 182 adolescent women, ages 14-18 years, to assess the prevalence of dysmenorrhea, the morbidity associated with dysmenorrhea, and the level of knowledge regarding available treatment. Of the study group, 72.7% reported "pain or discomfort" during their period, 58.9% reported decreased activity, and 45.6% reported school or work absenteeism. Of the dysmenorrheic sample, only 15.5% had used a prescription medication and only 14.7% could name any nonsteroidal antiinflammatory agent, except aspirin, as potentially effective in relieving dysmenorrhea. These data suggest that there is substantial ignorance or misinformation among adolescent females regarding effective treatment for dysmenorrhea. The prevalence of school and work absenteeism provides evidence for the continuing importance of dysmenorrhea as a public health problem of this age group. Discussion of effective therapeutic options for dysmenorrhea should be part of routine health care visits for adolescent women.

Absenteeism↗
PubMed1988

Systemic perfusion: a method of enhancing relative tumor uptake of radiolabeled monoclonal antibodies.

We evaluated the feasibility of systemic vascular perfusion with saline (mimicking plasmapheresis) as a method to enhance tumor-specific monoclonal antibody (MoAb) tumor/background ratios. Initially, groups of rats were injected intravenously (i.v.) with 131I-5G6.4 MoAb (murine IgG2aK reactive with ovarian carcinoma). These animal's radioactivity levels were determined by dose calibrator and they were imaged before and after perfusion which was conducted at 4 or 24 h post-antibody injection. Animals were sacrificed after perfusion, as were controls, and normal organ radioactivity levels determined. In addition, nude mice bearing HTB77 ovarian cancers subcutaneously were injected i.v. with 131I-5G6.4 MoAb and were imaged before and after systemic perfusion with saline 24 h post-5G6.4 injection. Perfusion in rats dropped whole-body 5G6.4 levels significantly at both perfusion times (P less than 0.0005). The drop in whole-body radioactivity with perfusion was significantly greater for the animals perfused at 4 h post i.v. 5G6.4 antibody injection (48.3 +/- 5.1%) than for those perfused at 24 h post i.v. antibody injection (32.9 +/- 2.9%) (P less than 0.025). In the nude mice with ovarian cancer xenografts, gamma camera images of tumors were visually and quantitatively (by computer image analysis) enhanced by perfusion, with a 2.33-fold greater decline in whole body uptake than in the tumor (P less than 0.05). These studies show that (1) much background antibody radioactivity can be removed using whole-body perfusion with saline, (2) that the decline in whole body activity is larger with 4 than 24 h perfusion and (3) tumor imaging can be enhanced by this approach.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

Forearm and finger hemodynamics, blood pressure control, and lipid changes in patients with diabetic hypertension treated with atenolol and prazosin.

Hypertension and diabetes mellitus frequently coexist and are independent risk factors for reduced peripheral perfusion. Antihypertensive medications that reduce blood pressure and improve peripheral perfusion would have advantages in diabetic patients with hypertension. In a randomized, two-placebo period, single-blind, two-way crossover study, we determined finger and forearm blood flow, lipid levels, and blood pressure control in 19 diabetic patients with hypertension, with each atenolol or prazosin and placebo period of 4 weeks' duration. Both drugs reduced blood pressure (sitting: 157/95 to 142/84 mm Hg, atenolol; 155/95 to 138/82 mm Hg, prazosin; standing: 154/94 to 144/84 mm Hg, atenolol; 154/94 to 133/81 mm Hg, prazosin). Lipid levels did not change except that low-density lipoprotein levels fell from 148 to 127 mg/dl with prazosin. Atenolol did not change forearm or finger blood flow or vascular resistance. Prazosin increased blood flow and reduced vascular resistance in both finger and forearm. In conclusion, prazosin has a potentially more appropriate hemodynamic profile than has atenolol in diabetic patients with hypertension.

Adult↗
PubMed1988

Comparative effects of verapamil and isradipine on steady-state digoxin kinetics.

The effects on the steady-state digoxin pharmacokinetics of verapamil (240 mg/day) and a new dihydropyridine calcium channel blocker, isradipine (15 mg/day), were compared. Nineteen healthy white men, aged 23 to 40 years, ingested 0.25 mg digoxin tablets every 12 hours for two consecutive periods of 2 weeks. Each subject also received one of the calcium channel blockers during one of these periods, with agent and sequence randomized. Analyst-blind RIA serum digoxin determinations demonstrated that the nine subjects who received isradipine, 5 mg t.i.d., had a small increment in peak digoxin level from 2.3 +/- 0.6 to 2.9 +/- 0.7 ng/ml (p less than 0.05) but no significant change in steady-state level or AUC over 12 hours. By contrast, the 10 subjects who received verapamil, 80 mg t.i.d., showed significant increases in steady-state (0.9 +/- 0.1 to 1.3 +/- 0.2 ng/ml; p less than 0.001) and peak serum digoxin concentrations (2.5 +/- 0.7 to 3.6 +/- 0.8 ng/ml; p less than 0.001) and in AUC (15.7 +/- 1.7 to 23.6 +/- 2.9 ng . hr/ml; p less than 0.001). Neither calcium channel blocker reduced renal digoxin clearance. Verapamil increases digoxin levels without affecting renal clearance. Isradipine has no clinically important interaction with digoxin.

Adult↗
PubMed1988

Risk factors for dehydration among elderly nursing home residents.

Dehydration is the most common fluid and electrolyte disorder among the elderly, yet risk factors are not known. This study identifies risk factors for dehydration in acutely ill nursing home residents. All 339 elderly resident of two nursing homes who developed an acute illness requiring hospitalization during 1984 were included in the study. The 173 patients having a serum Na less than 150 mg/dL and blood urea nitrogen to creatinine ratio (BUN:Cre) less than 20 were designated controls; 91 patients having a serum Na greater than 150 mg/dL or a serum BUN:Cre greater than 25 were designated cases. Odds ratios (OR) and confidence intervals were calculated for age, sex, chronic conditions, acute illnesses, medications, functional status measures, and season. Acutely ill dehydrated patients were female (OR, 3.3); over 85 years old (OR, 2.2); had more than four chronic conditions (OR, 4.0); took more than four medications (OR, 2.8); and were bedridden (OR, 2.9). Among the most severely dehydrated (serum Na greater than 150 mg/dL and BUN:Cre greater than 25), the odds ratios for the above factors were strengthened and other factors, such as inability to feed oneself and type of acute diagnosis, emerged as risk factors. Among the variables unrelated to functional status, laxatives (OR, 3.2) and chronic infections (OR, 1.8) were risk factors. We conclude that a group at high risk for dehydration can be defined and that they are better characterized by the number of chronic diseases and debilitated functional status than by acute disease processes.

Acute Disease↗
PubMed1988

111In-labeled platelet scintigraphy and two-dimensional echocardiography for detection of left atrial appendage thrombi. Studies in a new canine model.

111In-labeled platelet scintigraphy and two-dimensional echocardiography were performed in 40 dogs to determine the ability of the two techniques to detect left atrial appendage thrombi. Thrombi were induced in 33 dogs that were classified into two groups, "acute" or "chronic," according to the time of labeled-platelet injection after thrombus induction. In the acute group (17 dogs), platelets were injected 24 hours after thrombus induction. In the chronic group (16 dogs), platelets were injected 4-8 days after thrombus induction. "Sham" thoracotomies were performed on seven additional control dogs who did not receive thrombin injections. Analog and blood pool-corrected 111In-labeled platelet scintigraphy images were obtained 4-72 hours later. Closed-chest two-dimensional echocardiography was performed before thoracotomy and repeated at the time of scintigraphy. The location and size of each thrombus were verified at autopsy. Two-dimensional echocardiography detected three of 17 acute (mean volume, 1.2 +/- 1.0 cc) and three of 10 chronic (mean volume, 0.4 +/- 0.3 cc; p less than 0.025) left atrial appendage thrombi. 111In-labeled platelet scintigraphy detected all 17 acute thrombi but only two of 10 chronic thrombi. The measured radioactivity levels of the excised thrombi were 1,949 +/- 1,665 cpm/clot/dose in group 1 and 228 +/- 213 cpm/clot/dose in group 2 (p less than 0.005). In this model, 111In-labeled platelet scintigraphy was able to detect acute left atrial appendage thrombi that could not be identified by two-dimensional echocardiography. Both techniques showed poor sensitivity for detection of chronic thrombi. The decline in sensitivity of 111In-labeled platelet scintigraphy for detection of older thrombi is probably due to diminished labeled-platelet incorporation.

Animals↗
PubMed1988

Havelock Ellis.

Explore the source record for details and available documents.

England↗
PubMed1988

Cotinine in the serum, saliva, and urine of nonsmokers, passive smokers, and active smokers.

Cotinine was measured in the serum, saliva, and urine of nonsmokers, passive smokers, and active smokers. Serum and saliva could not discriminate between nonsmokers and passive smokers. Mean urine cotinine was higher in passive smokers than nonsmokers but there was a great deal of intersubject overlap. Cotinine in all body fluids could separate active smokers from the other two groups. Among smokers, light smokers had lower levels than heavier smokers.

Adult↗
PubMed1988

The role of immunotherapy in cockroach asthma.

To evaluate the preventive role of immunotherapy in severe perennial asthma, we investigated cockroach asthma as a model. Twenty-eight subjects with bronchial asthma due to cockroach hypersensitivity (BACR) were divided into two groups in alternating order: 15 were started with cockroach antigen immunotherapy (CRa-IT) and 13 were given control immunotherapy. Eleven in the former group and two in the latter group completed the study after 5 years. The changes in symptoms and medication scores were assessed; blocking antibody factor in the paired pre- and postimmune serum of the two groups was measured and compared. Cellular sensitivity (HR50) was measured using the basophil-rich leukocytes (BRLs) obtained from the two treated asthma groups, and the result was compared with that of the untreated cockroach asthmatic cells. The average symptom score changed from 7.2 +/- 2.7 to 1.2 +/- 0.4 in the CRa-IT group. The control-IT group showed no change. The medication score changed from 11.4 +/- 1.6 to 5.2 +/- 1.4 in the CRa-IT group only (p less than 0.01). The mean blocking antibody factor in the immune serum of the CRa-IT group showed a 2.5 x 10(2)-fold increase [1.3 +/- 0.3 x 10(-1) in postimmune serum/5.2 +/- 2.0 +/- 10(-4) in preimmune serum (p less than 0.001)]. No difference was noted in the HR50 of the BRLs in the post- and preimmune serum of the control-IT group. Antihuman IgG absorption of the post-CRa-IT serum reduced the blocking antibody to 1/1000-fold; no difference in the HR50 of the BRLs was noted between the post-control-IT and the pre-CRa-IT serum (p greater than 0.2). The BRLs of the CRa-IT asthmatics, however, showed blunted sensitivity not affected by the serum factor (5.8 +/- 1.5 x 10(-2) micrograms/ml in post-CRa-IT serum and 5.6 +/- 1.3 x 10(-2) micrograms/ml in pre-CRa-IT serum) (p greater than 0.2). The BRLs of the control-IT group retained their cell sensitivity as well as the blocking effect of the CRa-immune serum. This study thus demonstrated that CRa-IT reduces symptom and medication scores clinically in cockroach-asthmatic subjects, and the CRa-IT produces the CRa-specific blocking antibody of the IgG type. It also reduces anaphylactic leukocyte sensitivity, which is not affected by humoral factor.

Anaphylaxis↗
PubMed1988

Inhibition of guanidinobenzoatase: evidence for multiple forms of this protease on different tumour cells.

Guanidinobenzoatase is a proteolytic enzyme capable of degrading fibronectin and is a tumour associated enzyme. 9-Aminoacridine is a competitive inhibitor of this enzyme and has been used to locate cells possessing this enzyme in wax embedded sections by means of fluorescent microscopy. Naturally occurring inhibitors of guanidinobenzoatase can be extracted from different tissues. These inhibitors show selectivity in their ability to inhibit the binding of 9-aminoacridine to different types of tumour cells which have invaded human liver tissue. Inhibition is non-competitive and reversible. The results indicate that guanidinobenzoatase exists in a number of different forms on the surface of different tumour cells. These different forms of the enzyme were recognised by inhibitors obtained from different organs. It is suggested that these inhibitors may have a regulatory role in tumour cell migration.

Aminacrine↗
PubMed1988

Anticoccidial activity of combinations of narasin and nicarbazin.

The efficacy of mixtures of narasin and nicarbazin were evaluated by comparing broiler performance, susceptibility to heat stress, and the mode of action against Eimeria. In a floor pen trial, narasin (70 ppm) alone or in combination with nicarbazin at levels between 10/10 and 50/50 ppm gave significantly better performance than unmedicated birds or birds given nicarbazin at 125 ppm alone. Amelioration of nicarbazin-associated mortality with heat as a stressor was observed in birds given the 50/50 ppm mixture of narasin and nicarbazin: mortality in these birds was similar to that of unmedicated birds and was reduced by 15 to 20% of that occurring in birds in the nicarbazin (125 ppm) treatment. The narasin/nicarbazin mixture (50/50) appears primarily to prevent further development of sporozoites. However, in birds treated with 25/25 ppm of narasin and nicarbazin, both the deleterious action of nicarbazin on merogeny and the antisporozoite activity of narasin were observed.

Animals↗