Search PubMed⌕ Search

Biomedical subjects

J Johnson

Publications and source records attributed to J Johnson.

At least 523 records · Page 29Linked to original sources
PubMed1987

The comparative effects of verapamil and a new dihydropyridine calcium channel blocker on digoxin pharmacokinetics.

Conflicting conclusions have been reported about interaction of calcium channel blockers with digoxin. The effects of verapamil (240 mg/day) and a new dihydropyridine calcium channel blocker, isradipine (15 mg/day), on the pharmacokinetics of 1 mg intravenous digoxin were compared. All 24 volunteer subjects were healthy, male, nonobese, and aged 18 to 38 years. Groups of 12 subjects received each oral agent over 15 days, with collections of blood and urine for 72 hours after intravenous digoxin. Significant (P less than 0.05) reduction in nonrenal (7.01 +/- 1.97 to 4.00 +/- 1.86 L/hr) and total clearance (14.1 +/- 2.6 to 11.5 +/- 2.5 L/hr) were induced by verapamil, without change in renal clearance. A near-significant (P less than 0.1) increase in peripheral volume of distribution contributed to prolonged elimination half-life (23.1 +/- 4.4 to 34.3 +/- 9.7 hours). By contrast, isradipine caused only a 9% reduction in volume of distribution. Verapamil causes digoxin accumulation by reducing nonrenal elimination. No evidence of clinically relevant interaction of isradipine with digoxin was seen.

Adolescent↗
PubMed1987

A program model for nurses involved with cancer education of black Americans.

In the last 30 years, cancer incidence rates for black Americans have increased 27% in contrast to an increase of 12% for white cancer rates. In answer to this obvious need for intervention to lower the incidence and mortality rates, the Oncology Nursing Society held a one-day workshop which focused on the primary prevention of cancer in black Americans. For the 40 workshop openings, 540 black nurses from 40 states responded to a call for applicants. The impact of the workshop was measured by four pre- and post-tests which provided both qualitative and quantitative data and indicated that the experience made a significant impact on the participants. The workshop content focused on the epidemiology of the cancers which are most frequently found in blacks, cultural attitudes toward these cancers, and techniques for early detection. The success of the workshop was due to the active involvement of the participants in the learning process and serves as a model for training minority nurses for active, creative roles which can be instituted in the community to help lower the high cancer incidence rate among black Americans.

Black or African American↗
PubMed1987

Factors affecting the level of kanamycin resistance in transformed sunflower cells.

A 230 base pair DNA segment containing the sequences 5' to the 700 to 750 nucleotide (nt) transcript 7' (ORF 3; RF Barker, KB Idler, DV Thompson, JD Kemp 1983 Plant Mol Biol 2: 335-350) of the octopine tumor inducing plasmid pTiA6 has been isolated. This region has (a) 180 base pairs of DNA upstream of the TATA box, (b) the start of RNA synthesis, and (c) the entire 5' untranslated region of the gene. We have fused this presumed promoter fragment to the neomycin phosphotransferase II (NPTII) gene from Tn5 in a plant expression cassette. After recombination into a tumor inducing plasmid delivery plasmid, this cassette confers selectable kanamycin resistance to transformed sunflower cells. Removal of the out-of-frame ATG in the 5' leader sequence of the NPTII gene by two different modifications increased both the levels of NPTII enzyme activity and the ID(50) for kanamycin in the tumor cells. The promoter region of the transcript 7 gene gives levels of kanamycin resistance equivalent to the nopaline synthase promoter and octopine synthase promoter when used in the same constructions and assayed in the same tissues.

Journal Article↗
PubMed1987

Phaeohyphomycotic cyst caused by a recently described species, Phaeoannellomyces elegans.

An 81-year-old man presented with a chronic, painful nodule on the palmar surface of the left fourth finger. As a former farm worker, the patient acknowledged frequent soil-contaminated wounds of the left hand 4 to 12 years previously, but he denied any recent trauma. The patient's other medical problems included a history of chronic immunoglobulin A gammopathy and a new pleural mass eroding into adjacent ribs on chest X-ray. The finger nodule was excised and consisted of an intact phaeohyphomycotic cyst which yielded growth of a darkly pigmented fungus. At 25 degrees C, the isolate formed annellidic yeast cells having dark-brown walls consistent with the recently described species Phaeoannellomyces elegans. In vitro antifungal susceptibility tests indicated resistance to amphotericin B and variable susceptibility to imidazoles. The lesion was excised, and the patient received no antifungal therapy. After 9 months of follow-up, the fungal infection shows no signs of recurrence.

Aged↗
PubMed1987

Maintaining performance of autistic clients in community settings with delayed contingencies.

To facilitate the classroom and workshop integration of three autistic clients, we examined the feasibility of teaching them to respond appropriately without the continual presence of specially trained treatment providers. Within a multiple baseline design, a 4-step treatment process was implemented to promote durable responsive performance. Results indicated that the therapist could be removed from the treatment environment and that appropriate behavior could be successfully maintained in community settings with only infrequent and delayed contingencies.

Adolescent↗
PubMed1987

Gene therapy for thioguanine-resistant human leukemia.

The feasibility of using retroviral gene therapy to overcome drug resistance was assessed by determining the efficiency by which a retrovirus containing the human HGPRT gene could sensitize hypoxanthine-guanine phosphoribosyltransferase (HGPRT) negative human promyelocytic leukemia cells to 6-thioguanine. A single three-hour exposure at a virus to cell ratio of 6 X 2:1 restored sensitivity to 70(+/- 18)% of the clonogenic cells. The efficacy varied as a function of virus concentration and duration of viral exposure; the time allowed for integration and expression between one and five days post-infection had little effect. Cells successfully sensitized contained a proviral insert and expressed HGPRT activity that ranged from 1 to 92% of that in the wild-type cells. The mutation rate of the inserted gene varied from the same as that of the endogenous HGPRT gene to 200-fold greater in different clones. Failure of sensitization following viral exposure was associated with absence of an integrated provirus, and clonogenic cells failing to be sensitized by one virus exposure were sensitized with approximately the same efficiency by a second viral exposure. These results demonstrate the feasibility of transferring a drug sensitivity gene to a human leukemia cell line.

Cell Line↗
PubMed1987

Sexually transmitted diseases in adolescents.

Sexually transmitted organisms cause significant morbidity in adolescents, their sexual partners, and their offspring. The primary care physician may be effective in reducing the prevalence and sequelae of STDs in teenagers by being aware of the scope of this problem in the adolescent population as well as treatment options.

Adolescent↗
PubMed1987

Acute radiation-induced vomiting in area postrema-ablated cats.

A dose-response relationship was established in normal unanesthetized cats for emetic incidence, latency to onset of vomiting, and duration of emetic activity over a period of 24 h after whole-body exposure to 60Co radiation at selected doses between 7.5 and 90 Gy. Each episode of vomiting, i.e., retching and expulsion, was recorded oscillographically as its characteristic intrathoracic pressure waveform by means of a catheter inserted some days before into the superior vena cava. The gamma-radiation dose of 45 Gy evoked vomiting optimally with an incidence of 92% and an average onset time of 98 min. When administered to animals prepared chronically with surgical ablation of the area postrema, the same dose of radiation evoked vomiting in four of five test cases and with an average time to onset that was not by either measure significantly different from normal. Vomiting was also elicited in all of six normal cats exposed to an intestinal dose of 45 Gy X radiation with the head shielded. The same form of irradiation evoked vomiting in two of three chronically postremectomized cats. Successful ablation of the area postrema was determined functionally by emetic refractoriness to an injection of digitalis and confirmed for completeness by histological examination. It is concluded that the area postrema is not an essential element in the reflex mechanism of radiation-induced vomiting and, therefore, no physiological basis exists for dependence on a centrally acting chemogenic factor in radioemesis.

Animals↗
PubMed1987

Active vs. passive attentional manipulation and multidimensional perceptions of exercise intensity.

The purpose of this study was to ascertain whether active (arithmetic problems) or passive (asynchronous music) attention demanding tasks affected undifferentiated ratings of exertion during work of varying intensities. Also, an effort was made to determine which aspect of perceived exertion, (i.e., Fatigue, Task Aversion, and Motivation) as measured by the Physical Activity Questionnaire (PAQ), the attentional manipulation affected most. Twenty-six female subjects performed 5 minutes of work at either 60 or 90% of predicted VO2 Max. During work they were required to solve a constant flow of arithmetic problems, listen to music, or work in an unfilled control condition. Following activity they completed the PAQ and Borg's Scale. A repeated measures MANOVA followed by step-down F tests revealed that the Fatigue factor of the PAQ was the only component significantly (p less than .01) affected by attentional manipulation. A Scheffé test showed that both active and passive manipulation differed from the control (p less than .01), with active manipulation more potent at 90% VO2 Max.

Adult↗
PubMed1987

Williams syndrome: features in late childhood and adolescence.

Nine children with the Williams syndrome were evaluated for physical, neurodevelopmental, and behavioral characteristics to record the natural history of this disorder. The study subjects, who ranged in age from 10 years to 20 years, generally showed lower than expected cognitive functioning with four of the nine functioning in the severely retarded range. However, all the children showed uneven developmental profiles, compared to measured IQ, with reading abilities exceeding the expected level and visual-motor skills deficient for overall performance expectations. All but one child had evidence of supravalvular aortic stenosis on echocardiography, but there was little morbidity from cardiovascular disease in this group of patients. Although all had grown at or below the fifth percentile in early childhood, seven now were above the fifth percentile for height. Personality attributes that characterize younger children with Williams syndrome persisted in this group of older children.

Achievement↗
PubMed1987

Health care needs of Indochinese refugee teenagers.

Although 50% of Indochinese refugees are under 18 years of age, previous studies have emphasized the prevalence of parasites, anemia, tuberculosis, and hepatitis, with few addressing age-related health care needs. In this study the specific health care needs of 80 Indochinese refugee teenagers, evaluated during a 4-year period, were determined. The Centers for Disease Control's suggested screening measures were used, and it was found that 52% had positive purified protein derivative skin tests, 38% lacked immunizations, 35% had stool specimens positive for parasites (prevalence and number of parasites greatest among Cambodians), 14% had blood tests positive for hepatitis B surface antigen, and 10% were anemic. Additional evaluations showed that 19% had hemoglobinopathies, 14% were in or below the fifth percentile for height and weight, 12% had goiters, 12% had skin disorders, 8% had positive hepatitis B surface antigen, 5% had visual defects, 5% had hearing loss, 5% had psychosomatic illness, and 4% had idiopathic scoliosis. Although suggested Centers for Disease Control screening measures may be adequate for younger Indochinese children, these data suggest that additional studies are necessary for teenagers. For the sexually active adolescent, identification of and counseling for hepatitis antigenemia and hemoglobinopathies are crucial. In addition, early identification of emotional and physical problems during screening may enhance assimilation into a new society and facilitate completion of the psychosocial tasks of adolescence.

Adolescent↗