Search PubMed⌕ Search

Biomedical subjects

R Johnson

Publications and source records attributed to R Johnson.

At least 595 records · Page 33Linked to original sources
PubMed1980

Attitudes toward weight gain in pregnancy.

Recently, there has been increased interest in the influence of maternal prenatal nutrition on the course and outcome of pregnancy. Evidence has accumulated that a woman's weight before pregnancy and the weight gained during pregnancy directly affect infant birth weight, incidence of neonatal mortality, and growth and development of the infant during the first year of life. Although recent recommendations for weight gain in pregnancy have been liberalized, a survey of 195 pregnant women who had prenatal visits in both clinic and private offices showed deficiencies in their understanding of the subject. Some 37 percent of women believed they should gain 20 pounds (9 kg) or less during pregnancy. Eight percent admitted to dieting before at least one antenatal visit and 54 percent thought their doctor would not be concerned about too little weight gained during pregnancy. This suggests that many women and some doctors are still ignorant of current concepts of proper nutrition during pregnancy. Apparently, increased lay and professional educational efforts are needed.

Attitude to Health↗
PubMed1980

T4-throid storm in pernicious anemia.

A 32-year-old woman first had thyrotoxicosis and severe pernicious anemia (PA) in 1975. The initial serum thyroxine (T4) level, 14.5 microgram/dL, rose to 29.2 microgram/dL, with no other therapy except cyanocobalamin injection and blood tranfusions. She again had thyroid storm and PA in 1978. The serum T4 level was only slightly elevated, but the triiodothyronine (T3) level was normal. She received therapy for both diseases and recovered. Four months later, with a normal hematocrit reading, thyrotoxicosis recurred, with noticeable elevation of T4 and T3. These data suggest that first, thyroid storm can occur with excess T4 only, and its occurrence does not depend on the degree of thyroid hormone elevation; and second, thyroid hormone level may be depressed in severe PA, and a normal T3 level should not rule out thyrotoxicosis in this condition.

Adult↗
PubMed1980

The characteristics and natural history of tinnitus in Meniere's disease.

Four tests for the identification of tinnitus have been presented: pitch, loudness, maskability, and residual inhibition. The typical features of the tinnitus associated with Meniere's disease are as follows: 1. Usually the tinnitus is a low pitched noise. However, in the burned out condition it is often higher in pitch and tonal in quality. 2. The loudness match occurs at very low sensation levels. 3. Masking as a relief procedure is usually easily achieved, requiring only low levels of noise. 4. The masking recommended for relief of tinnitus is found to be acceptable as a substitute for tinnitus. 5. Masking of the tinnitus produces residual inhibition, which frequently is of longer than average duration.

Female↗
PubMed1979

Novobiocin; an inhibitor of the repair of UV-induced but not X-ray-induced damage in mammalian cells.

In addition to inhibiting replicative DNA synthesis in HeLa cells, novobiocin has a severe effect on the cellular response to UV irradiation, reducing the number of breaks made in pre-existing DNA by the excision repair process. The inhibition of UV repair by novobiocin is reflected in enhanced UV-killing of these cells. Rejoining of DNA after X irradiation is not impaired by novobiocin. The recognition and removal of UV damage may require unwinding of the DNA by gyrase, which--in bacteria--is the target for novobiocin.

DNA Repair↗
PubMed1979

Dinitrochlorobenzene responsivity: difference between patients with severe pulmonary coccidioidomycosis and patients with disseminated coccidioidomycosis.

Immunologic responses in 15 patients with severe pulmonary coccidioidomycosis and in 50 patients with disseminated coccidioidomycosis were measured by determination of complement-fixing (CF) antibody titers to coccidioidin in serum, coccidioidin (1:100) skin tests, and sensitization to dinitrochlorobenzene. Among the patients with desseminated coccidioidomycosis, the nine with CF antibody titers of less than or equal to 1:8 had normal responses to dinitrochlorobenzene, but the 41 with titers of greater than or equal to 1:16 had responses that were significantly lower than those of controls (P less than 0.001). In contrast, all patients with severe pulmonary coccidioidomycosis had CF antibody titers of greater than or equal to 1:16 and had responses to dinitrochlorobenzene that were greater (but not significantly greater) than those of controls. Among subjected with antibody titers of greater than or equal to 1:16, responsiveness to coccidioidin was found in 27% of those with severe pulmonary disease and in 39% of those with disseminated disease. Thus impaired responsivity to dinitrochlorobenzene in coccidioidomycosis is restricted to patients who have disseminated illness and high titers of CF antibody and is separable from lack of responsiveness to coccidioidin.

Antibodies, Fungal↗
PubMed1979

Hydroxychloroquine in prophylaxis of pulmonary embolism following hip arthroplasty.

Two thousand one hundred and forty four patients received Plaquenil (hydroxychloroquine sulphate) prior to total hip arthroplasty; the drug was continued until the patient was fully mobile. Fatal emboli (confirmed by postmortem) occurred in 0.28% and non-fatal emboli (diagnosed clinically) occurred in 4.15%. This was a statistically significant improvement over the overall results of all previous prophylactic measures used in this unit. The results of Plaquenil are significantly better than the most effective agent previously used in this unit, namely, Dindevan (phenindione). There were no deaths and no serious gastrointestinal or genitourinary bleeding. Allergic rashes occurred in 18 patients (0.8%), temporary blurring of vision in 6 (0.3%), and minor gastrointestinal upsets, including nausea, vomiting and minor bleeding in 12 (0.6%).

Dextrans↗
PubMed1978

On how P300 amplitude varies with the utility of the eliciting stimuli.

The bulk of the relevant evidence indicates that stimuli which elicit the P300 component of the human event-related potential (ERP) tend to be unexpected and task relevant. Yet, contradictory evidence has been presented which implied that P300 amplitude is modulated by the intensity difference between two equally relevant, equally probable feedback stimuli (Adams and Benson, 1973). The two experiments reported here were designed to clarify this contradiction. Subjects were instructed to press a button one second after a cue light. A tone at one of two intensities was presented 200 msec later indicating whether the time estimate was 'correct' or 'incorrect'. The magnitude of P300 varied as a function of the difference in intensity between S+ and S-; the smaller the difference, the smaller was P300, regardless of stimulus meaning (S+ or S-). We attribute this effect to the degree to which the subject chooses to utilize the tones in the performance of the time estimation task. In support of this hypothesis, we found that performance of the subjects as time estimators degraded as the difference between S+ and S- decreased. Moreover, a study of choice reaction times taken for the different pairings of S+ and S- showed that the stimulus pairs were not equally discriminable. It appears that as the S+/S- pairs become increasingly difficult to discriminate, their feedback value decreased and this decrease is positively correlated with a decrease in P300 amplitude. This interpretation received support from Exp. 2 in which the stimulus conditions were the same as in Exp. 1, but the subject's task was to count the "s+ stimuli. Here, when subject had no option but to process each individual stimulus, the P300 amplitude remained constant despite variations in S- intensity. Thus, it appears that task relevance must be defined in terms of the subject's behavior rather than by the experimenter's instructions to the subject.

Acoustic Stimulation↗