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Biomedical subjects

S Newman

Publications and source records attributed to S Newman.

At least 145 records · Page 8Linked to original sources
PubMed1986

Acute febrile cerebrovasculitis: a syndrome of unknown, perhaps rickettsial, cause.

In late 1983, five patients living near Charlottesville, Virginia, were treated for an unusual syndrome of fever, headache, altered mentation, multifocal neurologic signs, and cerebrospinal fluid pleocytosis. Clinical signs of brainstem disease developed in four patients. All five had had recent exposure to forests or wood and contact with flea-infested dogs. Two patients died; one survivor has had recurrent seizures. Brain biopsy samples in two patients and autopsy findings in another showed cerebral vasculitis and perivasculitis involving mostly venules and capillaries. In the autopsy, the severest vascular lesions involved the brainstem and thalami, where they were accompanied by acute fibrinoid necrosis, but discrete vascular lesions of lesser intensity were randomly distributed in the white matter and cortex. Serologic studies on paired specimens in four patients showed significant cross-reacting antibody responses to rickettsial (typhus-group) antigens in the indirect hemagglutination, latex agglutination, and IgM microimmunofluorescence tests, but no agent was visualized or isolated. The cause of this serious inflammatory disorder is unknown.

Acute Disease↗
PubMed1985

Lifetime parental productivity in twenty-seven crosses of mice. I. Birth traits.

Twenty-seven crosses derived from three random-mating, unselected strains of mice (SWO, J, PGH) with 16 matings/pureline or cross were cohabited continuously and monogamously for 365 d to evaluate long-term reproductive performance of the parents. Data from 3,249 litters born were analyzed to study the effects of parity (number of litters) and type of cross (pureline, two-way, backcross, three-way) on the following traits: 1) continuity of reproduction (COR), 2) litter size at birth (LSB), 3) age at first litter (AFL), 4) fraction alive at birth-the ratio of number born alive to LSB (FAB), 5) birth to birth interval (BBI) and 6) reproductive rate-the ratio of number born alive to birth to birth interval (RRT). Reproductive rate was also studied in a cumulative manner rather than on a per parity basis by regressing cumulative number born alive on cumulative birth to birth interval. Parity effects were important (P less than .01) for all traits measured. Differences among cross-types were highly significant for COR, LSB and RRT. Three-way crosses were more productive than backcrosses, and both were superior to two-way and pureline matings. Uniformity was greater among three-way crosses for all traits except COR. Cross-types differed importantly in the pattern of change in performance over parities for COR, LSB, FAB, RRT and cumulative number of live young (P less than .01). Number of parities were most important for variation in longevity of reproduction (COR) and somewhat for litter size (LSB). Mean and cumulative reproductive rates were influenced more by longevity and litter size than by interval between births.

Animals↗
PubMed1985

Lifetime parental productivity in twenty-seven crosses of mice. II. Weaning traits reflecting reproduction and lactation.

Twenty-seven crosses of mice derived from three random-mating, unselected strains (SWO, J. PGH) with 16 matings/pureline or cross were cohabited continuously and monogamously for a 365-d reproduction period to evaluate lifetime reproductive performance of the parents. Data from 3,249 litters born (2,792 surviving to weaning) were analyzed to study the effects of parity (number of litters) and type of cross (pureline, two-way, backcross, three-way) on certain traits measured at weaning (21 d). The traits evaluated were 1) weaning to weaning interval (WWI), 2) litter size at weaning (LSW), 3) fraction alive at weaning (FAW)-the ratio of LSW to number born alive, 4) total litter weight at weaning (LWT), 5) pup weight at weaning (PWT), 6) weaning weight per pup observed alive at birth (WPP), 7) parental feed consumption per day (FPD) and 8) parental costs (PCT). Cost per live weanling animal was estimated as the ratio of cumulative parental costs to cumulative number weaned. Cost per unit of weaning weight was defined as the regression of cumulative parental costs on cumulative litter weight. Parity effects were important (P less than .01) for all traits measured. Type of cross effects were noted for LSW, LWT, PWT, WPP, FPD (P less than .01) and PCT (P less than .05). A parity X cross-type interaction was expressed for WWI, LSW, PWT, WPP, FPD (P less than .01) and FAW (P less than .05). Three-way crosses were more productive than backcrosses, two-way crosses and pureline matings for all traits studied. Three-way crosses displayed the smallest cost per animal weaned and smallest cost per unit of weaning weight. The influence of parity on traits measured at weaning was less than for traits measured at birth. Weight per pup born alive (WPP) was found to be a better indicator of reproduction and lactation ability than LWT because WPP accounts for preweaning mortality.

Animals↗
PubMed1984

Respiratory muscle length measured by sonomicrometry.

The use of sonomicrometry to study the mechanical properties of the diaphragm in vivo is presented. This method consists of the implantation of piezoelectric transducers between muscle fibers to measure the fibers' changes in length. Ultrasonic bursts are produced by one transducer upon electrical excitation and sensed by a second transducer placed 1-2 cm away. The time elapsed between the generation of the ultrasound burst and its detection is used to calculate the intertransducer distance. Excitation and sampling are done at 1.5 kHz and the output is a DC signal proportional to the length change between the transducers. Neither irreversible injury to the diaphragm nor regional differences within an anatomical part or segment were noted. Measurements were stable within the physiological range of temperature. We measured costal and crural length and velocity of contraction in anesthetized dogs during spontaneous breathing, occluded inspirations, passive lung inflation, and supramaximal phrenic nerve stimulation. We found that shortening during spontaneous breathing was 11 and 6% for crural and costal, respectively. The crural leads the costal in velocity of shortening. Supramaximal stimulation results in a velocity of shortening of 5 resting lengths X s-1. During an occluded inspiration crural shortens as much as in the nonoccluded breath, whereas costal shortens less. During passive lung inflation there is a nearly linear relationship between lung volume and diaphragm length; however, the relationships of chest wall dimensions with diaphragm length are nonlinear and cannot be described by any simple function. Some of the implications of these data on the present understanding of diaphragmatic mechanics are discussed.

Animals↗
PubMed1984

Effects of age at slaughter and feeding regime on slaughter weight and carcass composition in mice.

Mice from three outbred stocks (PGH, J, and SWO) were fed either pelleted feed from overhead hoppers or ground feed from jars, from weaning at 21 days old to slaughter at 42, 49 or 56 days old. Live weights, weights of carcasses before and after extraction of carcass moisture and fat, and feed consumption were recorded. The PGH stock gained more in dry lean tissue and deposited less fat, and had a greater feed efficiency, compared to either of the other stocks. Males gained more than females, in both dry lean tissue and fat; females had a higher proportion of lean tissue and a greater feed efficiency. Increases in live weight between 49 and 56 days of age were mainly increases in fat content, especially in the offal portion of the body. Jar feeding restricted feed intake and reduced live weight gains. The reduction, however, was principally in fat deposition; feed efficiency was also greater for jar fed mice. It was found that the amount of lean tissue could be accurately predicted from carcass weight and carcass moisture measurements. It may be possible to estimate lean tissue accurately without employing the expensive and time consuming process of either extraction.

Adipose Tissue↗
PubMed1982

Prognostic factors in patients with non-small cell bronchogenic carcinoma and brain metastases.

Prognostic factors were examined in 38 patients with nonsmall cell lung carcinoma and brain metastases. The most important factors were the response to total therapy (corticosteroids, radiotherapy, and chemotherapy) and the presence of brain metastases alone; these factors had the most impact on survival. Age, sex, histologic type of lung cancer, and initial performance status were not prognostically important. Our results indicate that certain subgroups of patients with nonsmall cell lung carcinoma and brain metastases have a favorable prognosis and should be treated aggressively.

Adenocarcinoma↗
PubMed1982

Stimulation of de novo synthesis of cytochrome P-450 by phenobarbital in primary nonproliferating cultures of adult rat hepatocytes.

Primary monolayer cultures of nonproliferating parenchymal cells prepared from adult rat liver and maintained in serum-free medium responded to additions of phenobarbital with concentration-dependent increases in synthesis and accumulation of a cytochrome P-450 protein immunochemically and catalytically indistinguishable from that found in the livers of adult rats treated with phenobarbital. Maximal stimulation of the rate of synthesis of this cytochrome protein by phenobarbital, as much as 20-fold higher than in control cultures (1.01% of the rate of synthesis of total cellular protein), could be achieved when the drug was first added to cultures no older than 24 hr and then was maintained in the medium for 96 hr. In addition to phenobarbital, chemicals classified as "phenobarbital-like" inducers in vivo (mephenytoin, mirex, 2,2',4,4',5,5'-hexabromobiphenyl) induced synthesis in culture of this same immunoreactive protein. Supplementation of the medium with 0.1 microM H2SeO3 plus phenobarbital produced an average 2-fold enhancement in the rate of synthesis of this inducible cytochrome protein as compared to that in cultures receiving phenobarbital alone. Inasmuch as there was a decline in selenium content and in the activity of the seleno-enzyme glutathione peroxidase in hepatocyte cultures maintained in standard culture medium for more than 24 hr, the added selenium appears to correct a spontaneously acquired cellular deficiency in selenium. Contrary to the concept that liver cells placed in culture promptly dedifferentiate with general loss of specialized functions such as cytochrome P-450, our data demonstrate that expression of the phenobarbital-inducible form of cytochrome P-450 is not extinguished in culture, but rather it is masked transiently and is attenuated as the cells adapt to the imperfect conditions of the culture environment.

Animals↗
PubMed1979

Experimental studies of the etiology of genital exhibitionism.

Several studies are reported which examine the critical stimuli and responses as well as personality factors important in genital exhibitionism. Using penile volume measurement, sex history questionnaires, personality tests, and behavioral observations, it was found that (1) exhibitionists responded most to mature females and were comparable to normals in reactions to children and men; (2) while exhibitionists indicated narcissistic desires in exposing, in a laboratory study they did not differ from controls in reactions to exposing with various reactions of the female, from sexual arousal and admiration to fear and anger; (3) the only strong features distinguishing exhibitionists from controls and other sexually anomalous subjects were peeping associated with orgasm and outdoor solitary masturbation; (4) exhibitionists seemed to be less assertive and less feminine than controls, but results were weak and inconsistent; (5) exhibitionists and controls did not differ in separation and divorce or marital satisfaction; (6) blood testosterone and penile reactivity of exhibitionists were within normal limits. Overall, the results suggest that most major theories of genital exhibitionism are wanting. It is suggested that narcissism and pedophilia be examined further in connection with exhibitionism.

Adult↗
PubMed1979

Hemisphere differences and judgments of simultaneity of brief light flashes.

A series of experiments was conducted to investigate the possibility of hemispheric specialization for judgments of the simultaneity of two light flashes. Right-handed subjects adjusted two light flashes until they appeared simultaneous. The comparison of measures derived from the two possible orders of the light flashes suggested that the right hemisphere of right-handed subjects performed the function of ordering visual stimuli in time. Two further experiments examined an alternative explanation, that of a left-to-right scanning mechanism, the results of which also suggested a hemisphere explanation. The results of these experiments are discussed in terms of previous research and theories which located a temporal ordering mechanism in the speech hemisphere.

Adolescent↗