[Organization of out-of the-hospital continued care].
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Ambulatory Care↗
Biomedical subjects
M Meltz
Publications and source records attributed to M Meltz.
Radio frequency electromagnetic exposure: tutorial review on experimental dosimetry.
Radio frequency (RF) dosimetry is the quantification of the magnitude and distribution of absorbed electromagnetic energy within biological objects that are exposed to RF fields. At RF, the dosimetric quantity, which is called the specific absorption rate (SAR), is defined as the rate at which energy is absorbed per unit mass. The SAR is determined not only by the incident electromagnetic waves but also by the electrical and geometric characteristics of the irradiated subject and nearby objects. It is related to the internal electric field strength (E) as well as to the electric conductivity and the density of tissues; therefore, it is a suitable dosimetric parameter, even when a mechanism is determined to be "athermal." SAR distributions are usually determined from measurements in human models, in animal tissues, or from calculations. This tutorial describes experimental techniques that are used commonly to determine SAR distributions along with the SAR limitations and unresolved problems. The methods discussed to obtain point, planar, or whole-body averaged SARs include the use of small E-field probes or measurement of initial rate of temperature rise in an irradiated object.
Animals↗
Nicotinamide ethers: novel inhibitors of calcium-independent phosphodiesterase and [3H]rolipram binding.
The synthesis and biological properties of a series of nicotinamide ethers are described. These compounds, structurally novel calcium-independent phosphodiesterase inhibitors, also inhibit the binding of [3H]rolipram to rat brain membranes and reverse reserpine-induced hypothermia in the mouse. Several compounds exhibited potent in vivo activity comparable to the standard agent, rolipram.
Animals↗
Calcium-independent phosphodiesterase inhibitors as putative antidepressants: [3-(bicycloalkyloxy)-4-methoxyphenyl]-2-imidazolidinones.
The synthesis and biological properties of a novel series of selective calcium-independent phosphodiesterase inhibitors are described. These compounds also inhibit the specific binding of [3H]rolipram to rat brain membranes and exhibit efficacy in preclinical models of antidepressant activity in mice, such as reducing immobility in the forced-swim test and reversing reserpine-induced hypothermia. Imidazolidinones 4 and 16 were found to be the most potent compounds studied.
Animals↗
[Case-controlled study of the prognosis of cardiac insufficiency in treated hypertensive patients].
The aim of this study is to compare the long-term mortality of hypertensive subjects (HT) hospitalized with early heart failure (HF), and HT control without HF. The study is based on a population of 2,050 HT consecutively hospitalized for the first time for high blood pressure, between oct. 1969 and nov. 1983. Among them, 115 presented with early HF (symptoms for less than 3 months, the diagnosis being made mainly on interview data, physical exam, and radio); they were matched with Controls (C) belonging to the same hypertensive population, on the following criteria: same sex, same age (+/- 3 years), same date of entry (+/- 3 months), no HF at entry, 94 Cases (CHF) could be matched: 64 men and 30 women (mean age: 50 +/- 11). A mortality survey was done in April 1985, with response rates of 96 p. 100 (CHF) and 98 p. 100 (C). The mean follow-up period was 11 years. At entry, CHF differed highly significantly form C in many ways, and mainly in higher systolic BP, more frequent ECG changes (LV voltage, J-ST-T changes), more severe fundus oculi changes. The survival rate was assessed by life-table method. As a whole, it was significantly reduced in CHF vs C (p/0.005); the 10-years survival rates were respectively 51% (CHF) and 71% (C). Case-control comparison was examined for both sexes, and after division by the median age (50 years): CHF survival was significantly reduced in women, and in subjects aged 50 and more (p/0.03); no significant difference was observed for men and before 50. CHF were dichotomized for each available item at entry, and lifetable comparison was compared in both issuing sub-groups; no significant difference was observed, but for the age, with a better survival in youngest subjects (p/0.01).(ABSTRACT TRUNCATED AT 250 WORDS)
Actuarial Analysis↗
Characterization of the rapidly labeled hybridizable RNA synthesized in L5178Y mouse leukemic cells. Hybridization lifetime studies.
An attempt is made to characterize the rapidly labeled hybridizable RNA of L5178Y mouse leukemic cells which has been shown to have similar base sequences when synthesized in two different stages of the cell cycle. The size of rapidly labeled RNA molecules was heterogeneous. For labeling times of 20 min or less, the per cent of hybridization was maximal. With longer labeling times, the per cent of hybridization decreased as radioactivity appeared in long-lived species of low hybridization efficiency; the radioactivity profile resembled the optical density profile in sucrose gradients. The lifetime of newly synthesized hybridizable RNA was studied by pulse labeling exponentially growing cells and then "chasing" with nonradioactive uridine. The per cent of hybridization was studied as a function of chase time. Three RNA groups, which comprised different proportions of rapidly labeled hybridizable RNA, were distinguished. The short-lived group had a half-life of 10 min, much less than the values reported in the literature for messenger RNA of mammalian cells. The half-life of 1-1(1/2) hr observed for a medium-lived group more closely corresponds to that of messenger RNA. A long-lived group had a half-life of approximately 20 hr. Specific activity measurements during chase indicate the presence of a "pool" of labeled uridine derivatives. The uridine of this pool appears to be nonexchangeable with but dilutable by exogenous uridine. A nontoxic concentration of actinomycin D was added to the chase media in an attempt to block the "pool effect". A rapidly degradable RNA was demonstrable both by specific activity and per cent of hybridization measurements.
Animals↗