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Biomedical subjects

J Smith

Publications and source records attributed to J Smith.

At least 1,405 records · Page 78Linked to original sources
PubMed1975

Notes on the radioimmunoassay of human thyrotrophin.

This paper describes the use of screened transfusion plasma as a source of human thyroid stimulating hormone (h-TSH) free protein for standardization of a conventional "double antibody" h-TSH radioimmunoassay. Serum and plasma immunoreactive h-TSH levels have been shown to be stable for up to four days at 4 degrees C and 25 degrees C. A 37 degrees C incubation procedure has been developed which gives an acceptable standard curve, but with some loss of "between batch" precision.

Drug Stability↗
PubMed1975

The effects of cosmic Particle radiation on pocket mice aboard Apollo XVII: V. Preflight studies on tolerance of pocket mice to oxygen and heat. Part I. physiological studies.

Tests were carried out on pocket mice to ascertain their tolerance to elevated oxygen pressures alone and to a combination of hyperoxta and heat in excess of that expected during the flight of the mice on Apollo XVII. the mice withstood oxygen partial pressures up to 12 pst at normal room temperature (24 degrees C, 75 degrees F) over a period of 7 days. A few mice previously exposed to increased PO2 died in the course of exposure to an oxygen pressure of 10 pst or 12 psi (517 mm or 620 mm Hg) for 13 d in ambient heat of 32 degrees C (90 degrees F). Supplemental vitamin E and physiological saline loading given prior to exposure had no apparent protective effect. The overall conclusion was that the pocket mice which were to go on Apollo XVII could readily survive the ambient atmosphere to which they would be exposed.

Adaptation, Physiological↗
PubMed1975

Nitrate determination in baby food, using the nitrate ion selective electrode.

The nitrate electrode has been utilized in the determination of nitrate content in food products. The AOAC xylenol method was employed for comparative results. A reasonable correlation (r=0.91) was found between the 2 methods in the analysis of 49 samples containing 30-350 ppm nitrate. At the average nitrate content (100 ppm) of these foods, the standard error was 4.3 ppm. The electrode responds directly to the ionic activity of the nitrate ion. It has a linear concentration range of 1-6000 ppm nitrate and can be used over a wide pH range. The electrode does respond to some extent to anions other than nitrate, and some interferences do occur. These interferences are easily controlled by the use of cation exchange resins. The Corning known addition (spiking) method is used on all samples to insure correct electrode response in solutions containing variable background ionic composition. The electrode has the advantage of simplicity, speed, reproducibility, and accuracy. Work time saved using the electrode as opposed to the xylenol method is about 7 hr for the analysis of 20 samples. Error, and the need for repeating analysis, is much less frequent.

Electrodes↗
PubMed1975

Identification by retarded and nonretarded children of stimuli varying along one, two, or three dimensions.

The effects of number and type of dimension of stimulus variation, type of dimensional combination, and delay of response upon the identification performance of retarded and nonretarded children were examined. A retarded-nonretarded subject difference in identification ability and delay effects found in an earlier study (Smith & Kaufman, 1972) was replicated, and a developmental effect for nonretarded children was found as well. A retarded-nonretarded subject interaction was indicated for the effects of increasing number of dimensions of variation and for the effects of type of dimensional combination (figure-figure combinations as opposed to figure-ground combinations).

Adolescent↗
PubMed1975

Ultrasound as an aid in the diagnosis and management of ovarian carcinoma: preliminary report.

Ultrasonic scanning was used to assist in the diagnosis and management of ovarian tumors. Tumor response to therapy was evaluated with sequential ultrasound examinations in conjunction with clinical observations. Contact B-mode scanning and physical examination were complementary in demonstrating a change in tumor size, delineating small amounts of ascites, and identifying early omental implants. The information was used to guide the patient's management by chemotherapy.

Adult↗
PubMed1975

Clinical aspects of anaerobic infections in the surgical patient.

Oxygen-sensitive anaerobic bacteria comprise the largest group of organisms among the human endogenous microflora. The oral cavity, vagina and colon are the areas where obligate anaerobes are predominant and can be isolated in very high numbers. Sepsis following surgery of any of these organs is frequently due to the escape of endogenous bacteria during the course of the operative procedure. To isolate and successfully identify most of these anaerobic microorganisms from clinical exudate, special collection and bacteriologic techniques are necessary. The acceptable anaerobic collection techniques mentioned above minimize exposure of the clinical specimen to atmospheric oxygen during collection and transfer. Clinical clues indicating anaerobic sepsis include a putrid odor of the exudate and evidence of abscess, necrosis or associated gas formation. The importance and value of the Gram stain in early identification of surgical sepsis is stressed. Treatment of infectious complications includes surgical drainage and specific antibiotics.

Abdomen↗
PubMed1974

Protection of lethally irradiated mice by spleen cells from neonatally thymectomized mice.

Long-lived, immunologically vigorous (C3H(f) x A(f))F(1) hybrids were produced after lethal irradiation by administration of spleen cells from C3H(f) or syngeneic donors. Further, neonatally thymectomized C3H(f) or A(f) strain donors reconstituted irradiated C3H(f) or (C3H(f) x A(f))F(1) hosts. In addition, C3H(f) spleen cells from nonthymectomized 10- to 15-day-old donors protected irradiated hybrid mice, but A(f) cells of young mice as well as of older mice produced graft-versus-host reaction and early death in irradiated C3H(f) or (C3H(f) x A(f))F(1) hybrids. Abrogation of secondary disease by treatment of irradiated mice with spleen cells from allogeneic neonatally thymectomized mice is possibly attributable to diminished immunologic competence of the cells grafted, followed by the development of immunological tolerance of the donor cells. Donor cells, receiving thymus influence in the recipient host after transplantation, could explain the long-lived immunologically vigorous radiation chimeras that did not experience graft-versus-host reactions. The findings of this study help to understand the differential susceptibility of A(f) and C3H(f) mice to development of tolerance to one another's antigens observed in prior investigations. It appears that, in these mice, the host thymus influences the maturation of the spleen cells from young mice or from neonatally thymectomized mice. However, this influence was often greater in mice given 767 rads than in those given 1046 rads. This differential influence is possibly attributable to irradiation damage to the thymus produced by the higher dose of irradiation. Spleen cells from neonatally thymectomized mice can be differentiated and expanded by the thymus of the host. The differential susceptibility of T(1), early differentiation stages, of thymus-dependent lymphocytes and T(2), late differentiation stages, of thymus-dependent lymphocytes to tolerance induction and immunostimulation, respectively, are proposed as the bases for these otherwise paradoxical influences.

Animals↗
PubMed1974

Mitochondrial DNA polymerase, deoxyribonuclease and ribonuclease H activities from brain of chick embryo.

R-DNA polymerase, D-DNA polymerase, DNase and RNase H activities in mitochondria from chick embryonic brain were studied by ion-exchange chromatography. Two main fractions were separated according to their chromatographic behaviour: a fraction M Ib which is eluted with the washing buffer from two successive DEAE-cellulose columns and a fraction M IV which is eluted at 400 mM KC1 from a phosphocellulose column. Although the two fractions contain both the DNA polymerase and the degrading activities, all the specific activities are higher in fraction M IV than in fraction M Ib. Heat inactivation experiments have shown that R-DNA polymerase is inactivated in both fractions, whereas RNase H and DNase are not affected. Thus, degrading activities and R-DNA polymerase activity seem to be catalyzed by different molecular entities. However the fact that in most cases these activities co-chromatograph suggests that the corresponding molecules form rather stable complexes.

Animals↗
PubMed1974

Local antibody production in experimental pyelonephritis: amount, avidity, and immunoglobulin class.

LOCAL ANTIBODY FORMATION IN INFECTED RABBIT KIDNEYS WAS STUDIED WITH THREE TECHNIQUES: the ammonium sulfate precipitation technique, the enzyme-linked immunosorbent assay, and by binding of newly synthesized (14)C-labeled antibodies to heat-killed bacteria. Local antibody was detected by day 11 of infection with all three techniques, and a significant correlation was found in titers by all three methods. In these studies, antibody synthesized early was in IgG and IgA class, whereas IgM antibodies appeared later (day 20) in the antibody response. No maturation of avidity of local antibody was noted with time. Since it was necessary to use different animals at each test occasion, individual differences in avidity could account for failure to note an increase in avidity with time.

Ammonium Sulfate↗