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Biomedical subjects

B Rosen

Publications and source records attributed to B Rosen.

At least 109 records · Page 6Linked to original sources

Complete atrioventricular block induced by methyldopa.

We present two patients who developed complete heart block due to treatment with methyldopa. After discontinuing methyldopa, conduction disturbances completely disappeared and recurred upon rechallenge with the medication. It is assumed that methyldopa can impair the myocardial conduction system by its central sympatholytic effect. Conduction anomalies should be excluded prior to treatment with methyldopa, and during treatment with the medication, the patients should be routinely screened for the presence of conduction anomalies.

Aged↗

The associations between 40 Hz-EEG and the middle latency response of the auditory evoked potential.

The study of the 40 Hz activity of the brain which was begun by Adrian (1942) has been furthered for the past years with several new approaches: A neural model for the generation of 40 Hz activity in attention has been published by Freeman (1975) whereas new possibilities in clinical applications and exploration of cognitive processes in an extended manner was proposed by Galambos and coworkers (1981). The present study demonstrates the relation between 40 Hz spontaneous activity in human EEG-recordings and the middle latency response of the auditory evoked potentials. The applied signal analysis method allows also a single trial analysis of EEG-EP epochs which can be extended in studies on cognitive processes. A perspective concerning the middle latency response of the auditory AEP is also given.

Acoustic Stimulation↗

Comparison of the effects of antihypertensive drugs on pre- and postglomerular vessels of the hydronephrotic kidney.

The in vivo renal microvascular effects of three antihypertensive drugs: nitrendipine, a calcium entry blocker, and two direct-acting vasodilator agents, hydralazine and minoxidil, were compared. The dilator responses of pre- and postglomerular vessels were directly observed after the topical or intravenous administration of each drug using the hydronephrotic kidney preparation and television microscopy. When applied directly to the kidney to avoid changes in systemic blood pressure, all three drugs preferentially dilated the preglomerular vessels. The largest increases in preglomerular vessel diameters were observed with nitrendipine followed by hydralazine and minoxidil, in the order listed. These drugs produced little change in efferent arteriole diameters though acetylcholine evoked significant dilator responses of the same vessels. When infused intravenously to lower blood pressure, the predominant effect of the drugs was on the afferent arteriole. No significant changes in the efferent arteriole diameter were observed with any drug. These data demonstrate that these vasodilators, which act primarily at preglomerular sites, probably increase glomerular capillary pressure, but to differing degrees.

Administration, Topical↗

Response of solitary psoriatic plaques to experimental application of podophyllotoxin.

A 16-week double-blind study of parallel groups was carried out in the treatment of 152 patients suffering from stable psoriasis vulgaris. Podophyllotoxin was applied once daily at three different concentrations in an ointment base, namely 0.1, 0.25 and 0.5%. One stable psoriatic lesion was selected and monitored during the study course. All three concentrations of podophyllotoxin induced a statistically highly significant improvement (p less than 0.001) of the selected lesions. There was statistically highly significant difference between the treated and control lesions already after 2 weeks of treatment (p greater than 0.001), and this difference increased further during the study course. Eleven patients experienced adverse reactions - severe skin rash - spontaneously reported by the patients.

Adult↗

Isolation and characterization of Z-DNA binding proteins from wheat germ.

The preparation of a heterogeneous non-histone protein extract from wheat germ utilizing Br-poly(dG-dC).poly(dG-dC) (Z-DNA) affinity chromatography is described. The binding characteristics of antibodies against Z-DNA are used as a model system to define important criteria that the DNA binding behavior of a Z-DNA binding protein should display. We show that the wheat germ extract contains DNA binding proteins specific for left-handed Z-DNA by these criteria. The affinity of the proteins measured by competition experiments was approximately 10(5) greater for Br-poly(dG-dC).poly(dG-dC) (Z-DNA) than for poly(dG-dC).poly(dG-dC) (B-DNA). The affinity of the proteins for plasmid DNA increases with increasing negative superhelicity which is known to stabilize Z-DNA. The proteins are shown to compete with Z-DNA antibodies for binding to supercoiled plasmids. Finally, the affinity for two plasmids at a given superhelical density is greater for the plasmid containing an insert known to form Z-DNA than for a plasmid without the insert. The proteins exhibit a 2-3-fold greater affinity for stretches of (dC-dA)n.(dT-dG)n over stretches of (dG-dC)n.(dG-dC)n when both sequences are induced to form Z-DNA by supercoiling.

Animals↗

Radon in soil gas--exhalation tests and in situ measurements.

Radon in soil can move into buildings resulting in high radon daughter concentrations. The foundation of a dwelling should be adapted to the radon "risk" which is determined by the radon concentration and the air permeability of the soil. Different measuring procedures are discussed in this paper, both in situ measurements of radon content and laboratory tests on radon exhalation from different types of soils at different water contents.

Environmental Exposure↗

An intervention to improve follow-up of patients with otitis media.

We evaluated the effects of an educational intervention and telephone reminders on compliance with medication-taking and appointment-keeping for children with otitis media. During an initial interview we examined parents' health beliefs and other factors associated with compliance in our outpatient setting. The children were then systematically assigned to one of five study groups (G1-5). Parents in G1 received an educational session with a nurse and two follow-up telephone reminders. Parents in G2 received only two telephone reminders. Parents in G3 met with the nurse for an educational session only. Parents in G4 were exempted from interventions, while parents in G5 were exempted from the interventions and the initial interview. The telephone reminder significantly increased the return rate for follow-up appointments (p less than 0.05). This effect was not enhanced by combining it with an educational intervention focusing more on medication compliance. Relatively simple and inexpensive interventions such as the ones described here improve follow-up appointment-keeping for children with otitis media. This enhanced compliance behavior is important in obtaining better health outcomes for children with acute illnesses.

Acute Disease↗

Nuclear magnetic resonance imaging of the vitreous body.

Imaging with proton nuclear magnetic resonance is a valuable new tool for studying the vitreous body of the eye. It is particularly suited for the detection of vitreal liquefaction and intraocular hemorrhage because of the dependence of the signal on the physical environment of water. Conversely, the vitreous body provides a new model for studying changes in proton relaxation times of protein solutions in biological systems.

Animals↗

A new approach to endogenous event-related potentials in man: relation between EEG and P300-wave.

The family of late positive waves which occur at latencies of 250 to 500 msec (P300) has been the most widely studied endogenous event related potential of the brain. We performed experiments with human subjects by applying repetitive acoustical tone bursts; every third or fourth signal was omitted. The endogenous potential related to the omitted stimulation was first averaged. The averaged record was then transformed to frequency domain with Fourier analysis in order to obtain the frequency characteristics. We observed frequency selectivities between 1-2.5 Hz, 3-8 Hz and between 8-13 Hz. After this procedure, single epochs of prestimulus EEG and endogenous potentials were pass-band filtered in the above frequency ranges. The comparison of filtered prestimulus EEG and of single endogenous responses gave the following results: In delta and theta frequency ranges the EEG prior to omitted stimulation showed in most of the trials a phase-reordering; the P300-wave seems to be a continuation of the ordered and stationary pre-EEG. In some cases the P300-wave depicts an amplitude-enhancement against the delta and theta components of the pre-EEG. Alpha-enhancement and alpha-blocking also make important contributions to the organization of the endogenous event-related potentials.

Adult↗

Evaluation of role of natural killer cells in radiation-induced leukemogenesis in mice.

The relationship of the leukemogenic and natural killer (NK)-suppressive effects of fractionated doses of gamma-radiation in mice was studied. A/J mice were relatively resistant; CBA/J, BALB/c, and C57BL/6 were susceptible to both the NK-suppressive and leukemogenic effects, and young (1 mo old) C57BL/6 mice were more susceptible than were 2- and 3-month-old C57BL/6 mice to both effects. Age-dependent susceptibility to radiation-induced leukemogenesis also was observed in C57BL/6 (bg/bg) (beige) mice. No differences in incidence and latent period of lymphoma development were found between C57BL/6 (+/+) and beige mice. Bone marrow cells (BMC) from normal C57BL/6 donors reconstituted the NK reactivity of irradiated C57BL/6 (+/+) or beige recipients and inhibited leukemogenesis. Although BMC of beige donors did not reconstitute the NK reactivity of irradiated C57BL/6 (+/+) or beige recipients, these cells were as efficient for antileukemic protection as were BMC from C57BL/6 (+/+) mice. The bone marrow of irradiated mice contained preleukemia cells that produced leukemias when transplanted iv into recipients preirradiated with 400 R. Inoculation (iv) of spleen cells (SpC) from syngeneic nude mice plus preleukemia bone marrow cells (PBMC) were able to inhibit leukemia formation in the 400 R-irradiated recipients. SpC from beige mice, normal C57BL/6 (+/+) mice, or C57BL/6 (+/+) mice treated with anti-asialo GM1 serum had no influence on the development of leukemia after their transplantation with PBMC.

Aging↗

A 15-year followup of 646 schizophrenic outpatients.

The 15-year hospitalization course of 646 chronic schizophrenic outpatients treated between 1958 and 1963 was determined using records of the research clinic, the Kings County Psychiatric Hospital, and the New York State Department of Mental Hygiene. The cohort was heterogeneous with regard to previous history of hospitalization: 20.6 percent had never been hospitalized, 22.0 percent had experienced only crisis admissions, and 57.4 percent had experienced long-term psychiatric hospitalization. The results indicate that 58.8 percent were hospitalized subsequent to project entry. A relationship was observed between previous history and hospitalization and hospitalization during the followup period. Patients with no previous history of hospitalization was less likely to be hospitalized than patients with crisis admissions only, who in turn were less likely to be hospitalized than patients with a history of hospitalization in a long-term psychiatric treatment facility (39.1 percent vs. 53.5 percent vs. 67.9 percent; p less than .001). The implications of these findings for future followup studies are discussed.

Adult↗

Body image: a selective review of existing measurement techniques.

A selective review of studies concerning body image is presented to illustrate the diversity of approaches which have been adopted. Equivocal definitions of the concept of body image and the difficulties inherent in its measurement are examined and the most popular measurement techniques are described and criticized.

Body Image↗