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Biomedical subjects

R Henderson

Publications and source records attributed to R Henderson.

At least 19 recordsLinked to original sources
PubMed1992

A system for studying the microstructure of ingestive behavior in mice.

A system for long-term monitoring of mouse eating and drinking behavior with 6-s resolution is described. The apparatus utilizes infrared beams to monitor activity at a single feeding port and electronic contact detector circuitry to record individual licks at two drinking ports. Eight SWR/J mice were monitored using this system and data from the last day of testing with food and water were analyzed. Mice ate an average of 4.54 +/- 0.40 g of powdered food and drank an average of 5.81 +/- 0.65 ml of water. Mice had an average of 36.25 +/- 3.96 food bouts and 32.25 +/- 7.56 water bouts lasting 3.00 +/- 0.48 and 0.88 +/- 0.35 min, respectively. Information regarding the temporal association between eating and drinking and the circadian patterns of ingestion was provided, utilizing customized software that augments the system. Important implications for the use of mice in ingestion pattern research are discussed.

Animals↗
PubMed1992

Image contrast in high-resolution electron microscopy of biological macromolecules: TMV in ice.

It is shown that the contrast in high-resolution electron micrographs of biological macromolecules, illustrated by a study of TMV in ice, falls considerably below the level which should theoretically be attained. The factors which contribute to the low contrast include radiation damage, inelastic scattering, specimen movement and charging. Future progress depends on improved understanding of their contributions and relative importance. Contrast is defined as the amplitude of a particular Fourier component extracted from an image in comparison to that expected by extrapolation from separate electron or X-ray diffraction measurements. The fall in contrast gets worse with increased resolution and is particularly serious at 10 A and beyond for specimens embedded in vitreous ice, a method of specimen preparation which is otherwise particularly desirable because of the expectation that the embedded molecules should be well preserved in a near-native environment. This low contrast at high resolution is the principal limitation to atomic-resolution structure determination by electron microscopy. In spite of good progress in the direction of better images, it remains a major problem which prevents electron microscopy from becoming a simple and rapid method for biological atomic structure determination.

Bacteriorhodopsins↗
PubMed1992

Preliminary examination of the comorbidity of anxiety and depression in Parkinson's disease.

Significant anxiety in combination with depression may represent a specific depressive subtype in Parkinson's disease (PD). To ascertain the prevalence of this symptom complex, we administered a self-report survey and standardized psychological tests that measure anxiety and depression to 164 PD patients and 150 age-matched healthy spouse control subjects. The reporting of depression in combination with panic/anxiety best differentiated the two populations (38% vs. 8%). Depression and anxiety were highly correlated in relationship to clinical features of PD. Our findings suggest that clinically significant levels of depression and anxiety may frequently coexist in PD. The specific neuropathology of PD may predispose to this pattern of behavioral disturbance.

Aged↗
PubMed1992

Lifetime sexual behaviors among predominantly minority male runaways and gay/bisexual adolescents in New York City.

Lifetime sexual behaviors were examined among two samples of predominantly minority, male adolescents in New York City aged 12 to 18 (M = 16.3), believed to be at high risk for HIV infection: 59 runaway males in two residential shelters and 60 males attending a community agency (HMI) for gay and bisexual youths. Interviews regarding psychosexual milestones indicated that 93% of these youths had engaged in oral, anal or vaginal intercourse and/or anilingus, with a median of 11.0 female partners among runaway males and a median of 7.0 male partners among HMI males. Both groups initiated sexual activity at a relatively early mean age of 12.6 years. Each group reported a unique developmental sequence of psychosexual milestones. Consistent condom use was reported by 13% of the youths. One quarter of the youths reported involvement in prostitution. These findings detail the need for AIDS prevention programs for these youths.

Adolescent↗
PubMed1992

An atomic model for the structure of bacteriorhodopsin, a seven-helix membrane protein.

A three-dimensional map of bacteriorhodopsin has been obtained, at near-atomic resolution, by collecting and analysing electron diffraction patterns and electron micrographs from crystals of bacteriorhodopsin preserved at very low temperatures. The map shows a resolution of 3.5 degrees in a direction parallel to the plane of the membrane, but poorer resolution perpendicular. It shows many features well resolved from the main density of the seven alpha-helices, which we interpret as the bulky sidechains of tyrosine, phenylalanine and tryptophan, as well as a very dense feature, which is the beta-ionone ring of the retinal chromophore. Using these bulky side chains as starting points and taking account of bulges of density for the smaller side chains such as leucine, we built an atomic model for the residues between 8 and 225. There are 21 amino acids from all 7 helices surrounding the retinal and 26 amino acids contributed by 5 helices that form the proton channel. Ten of the amino acids in the middle of the proton channel are also part of the retinal-binding site. The model provides a useful basis for considering the mechanism of proton pumping and in the interpretation of other experimental data. In particular, the model suggests that the pK changes in the Schiff base must act as the means by which light energy is converted to proton pumping through the channel. Asp-96 is on the pathway from the cytoplasm to the Schiff base and asp-85 on the pathway from the Schiff base to the extracellular surface. The experimental map and the building of the model of the structure will be described, as well as our interpretation of the structural basis of the mechanism.

Amino Acids↗
PubMed1990

Identification of Salmonella somatic and flagellar antigens by modified serological methods.

This report describes two modified methods for the identification of Salmonella somatic (O) and flagellar (H) antigens. Over a period of 2 years, both modified methods were found to be approximately three times less labor intensive than the standard methods while requiring no more technical skill. The modified methods were as accurate as the standard methods in identifying the O and H antigens of 350 Salmonella isolates. Furthermore, 43 O antisera reacted exclusively with organisms possessing homologous O antigens when the modified and two standard methods were used. At the antiserum dilutions used for H antigen identification, H antisera did not react with O antigens or heterologous H antigens by either the modified or the standard method. Compared with the standard method for H antigen identification, the modified method was approximately 20 times more economical with respect to antisera and usually generated a 1.5- to 4-fold higher titer. Since the antisera stored for use in the modified method for H antigen identification were usually 100-fold more dilute than the antisera stored for the standard method, an antibody-stabilizing buffer was incorporated in the diluted antisera, allowing these reagents to be used for at least 9 to 16 months.

Agglutination Tests↗
PubMed1979

Comparison of left ventricular ejection fraction by EKG-gated radionuclide techniques and contrast angiography using a microcomputer system.

The left ventricular ejection fractions of 53 patients were determined from multi-image cardiac blood pool scintigrams in the left anterior oblique position utilizing a microcomputer and floppy disc. These data were compared to ejection fractions obtained at cardiac catheterization in the right anterior oblique position. The ejection fraction obtained by radionuclide technique was comparable to that obtained by contrast angiography in the 53 patients with an r = 0.93. Forty-five patients with coronary artery disease showed an r = 0.92. In the coronary artery group with regional wall dysfunction, the correlation was r = 0.89.

Angiography↗
PubMed1979

First-pass or single-pass radionuclide angiography evaluation of left ventricular ejection fraction using a microcomputer system.

Left ventricular ejection fractions of 31 patients determined from first-pass or single-pass radionuclide angiography from the anterior position using a microcomputer system and floppy disc were compared to angiographic catheterization data obtained from the right anterior oblique position. This study demonstrated a good correlation with r = 0.91. To our knowledge, this is the first report of comparative first-pass left ventricular ejection fraction data and contrast angiography using a microcomputer system and a floppy disc.

Albumins↗
PubMed1978

Evaluation of workers exposed to elemental mercury using quantitative tests of tremor and neuromuscular functions.

Workers exposed to metallic mercury vapor were subjects for tremor, EMG, and psychomotor tests. Regression analysis revealed statistically significant trends in these test results related to workers' urine mercury histories. Effects were subclinical, functionally insignificant and most associated with those workers whose urine mercury had exceeded 0.5 mg/L in the previous year. In agreement with previous reports, effects were reversible upon reduction of mercury exposure.

Adult↗