Effect of an intracerebroventricularly administered vasopressin V1 antagonist on blood pressure and heart rate in deoxycorticosterone-salt hypertensive rats

It is well known that peripheral vasopressin (VP) is essential for the development and maintenance of DOC-salt hypertension. It is, however, still unclear whether central VP is involved in this type of hypertension. Therefore, the aim of this study was to clarify the role of central VP in the regulation of blood pressure in DOC-salt hypertension. In order to examine this issue, three series of investigations were performed. First, a novel vasopressin V1 antagonist (OPC21268) was administered intravenously to DOC-salt hypertensive rats, and mean arterial blood pressure (MABP) and heart rate (HR) were recorded. Second, the concentration of VP in the perfusate of microdialysis of cerebrospinal fluid (CSF) was determined in DOC-salt hypertensive and control rats. Finally, intracerebroventricular (i.c.v.) administration of a V1 antagonist was performed in DOC-salt hypertensive rats to determine the central mechanism of hypertension. Intravenous administration of a V1 antagonist had no effect on MABP and HR. There was no difference in VP in the perfusate of CSF between DOC-salt hypertensive and control rats. I.c.v. administration of a V1 antagonist significantly decreased MABP and HR in a dose-dependent manner in DOC-salt hypertensive rats (P < 0.05-0.01). These results suggest that central VP is involved in the maintenance of DOC-salt hypertension, and the mechanism is, in part, mediated by upregulation of the V1 receptor.

Pericardiocentesis and drainage by a silicon rubber line without echocardiographic guidance. Experience in 55 consecutive patients

Pericardiocentesis and drainage with a silicon rubber line were performed safely in 55 patients via the subxiphoid (80 times) or apical (1 time) approach at the bedside without echocardiographic guidance. The subxiphoid approach, which is close to the posterior of the sternum or the costal cartilage with a small acute-angle (15-30 degrees) to the parietal pericardium in front of the right ventricle, can avoid injuring the heart, liver and lungs. A line with sideholes near the distal end, which provides convenient drainage and has better histocompatibility, can be kept in place for a long period of time (1-82 days). It was also convenient to inject air, drugs or fluid through the line. There were no procedure-related serious complications or deaths. Emergency drainage with the Seldinger technique, especially for small to moderate effusions, is safe and simple.

The relationship of chronic diseases and health status to the health services utilization of older Americans

OBJECTIVE

To study simultaneously the relationships among chronic diseases and physical health status as they affect health services utilization of older adults.

DESIGN

Secondary analysis of a large, cross-sectional health interview survey, the Supplement on Aging of the 1984 National Health Interview Survey, using multiple equation methods to evaluate disease-specific impacts on physical health status, the direct impact of specific diseases on utilization of physician services and hospital care, and the indirect impact of specific diseases on utilization, mediated through physical health status.

PARTICIPANTS

A total of 11,497 people aged 65 and older, representing a complex, multistage sample of the noninstitutionalized, older adult population of the United States.

MEASUREMENTS

Predictor variables included specific chronic diseases (hypertension, arthritis, diabetes, cancer, and atherosclerotic heart disease), self-rated health status, and total number of disabilities. Control variables included age, gender, race, education, social integration. Outcome variables were physician visits and hospital stays.

MAIN RESULTS

It was shown that different diseases have different relative impacts on physical health status, probability of utilization, and amount of utilization, if any, and different chronic diseases have a different mix of direct and indirect effects on utilization.

CONCLUSION

The impact of chronic disease on health services utilization in a community-dwelling population is not a simple or direct relationship. Diseases vary according to their impact on different types of utilization, their impact on the probability of any health services use versus the amount of use, and on how much their effect on utilization is mediated through health status.

A study of spectral electroretinogram of color vision defects due to macular diseases

Studies of spectral electroretinograms in central serous retinopathy (CSR) and hereditary macular degeneration (HMD) showed that the b-wave amplitudes of most wavelengths of CSR were significantly decreased as compared with normal controls, and those of HMD were obviously lower than the normal values. Patients of HMD with type-A color vision defects (CVD) had primarily a reduction of b-wave amplitudes in the full spectrum of 480-620 nm, and patients with type-I CVD a reduction of b-wave amplitudes wave-lengths of 480-560 nm. These differences might reflect differences in damages to the medium-and long-wave length.

The pKa of the protonated Schiff bases of gecko cone and octopus visual pigments

A visual pigment is composed of retinal bound to its apoprotein by a protonated Schiff base linkage. Light isomerizes the chromophore and eventually causes the deprotonation of this Schiff base linkage at the meta II stage of the bleaching cycle. The meta II intermediate of the visual pigment is the active form of the pigment that binds to and activates the G protein transducin, starting the visual cascade. The deprotonation of the Schiff base is mandatory for the formation of meta II intermediate. We studied the proton binding affinity, pKa, of the Schiff base of both octopus rhodopsin and the gecko cone pigment P521 by spectral titration. Several fluorinated retinal analogs have strong electron withdrawing character around the Schiff base region and lower the Schiff base pKa in model compounds. We regenerated octopus and gecko visual pigments with these fluorinated and other retinal analogs. Experiments on these artificial pigments showed that the spectral changes seen upon raising the pH indeed reflected the pKa of the Schiff base and not the denaturation of the pigment or the deprotonation of some other group in the pigment. The Schiff base pKa is 10.4 for octopus rhodopsin and 9.9 for the gecko cone pigment. We also showed that although the removal of Cl- ions causes considerable blue-shift in the gecko cone pigment P521, it affects the Schiff base pKa very little, indicating that the lambda max of visual pigment and its Schiff base pKa are not tightly coupled.

The ear in the acquired immunodeficiency syndrome: I. Temporal bone histopathologic study

A postmortem histopathologic investigation of temporal bones of patients with the acquired immunodeficiency syndrome (AIDS) was performed after microslicing, acid decalcification of the slices and paraffin embedding. Histopathologic changes in 49 temporal bones from 25 patients included severe otitis media in five patients (20%), low-grade otitis media in fifteen (60%), labyrinthine cryptococcosis in two, Kaposi's sarcoma deposit in the eighth nerve of one, and cytomegalovirus (CMV) inclusion-bearing cells in the inner and middle ear of six (24%). It was possible to identify the CMV genome by in situ hybridization in only two bones and expression of CMV antigen by immunohistochemistry in none, probably because of prolonged decalcification in acid. The ear is no less susceptible to AIDS-associated diseases than any other organ, and is particularly prone to CMV infection.

Objective measurement of wave aberrations of the human eye with the use of a Hartmann-Shack wave-front sensor

A Hartmann-Shack wave-front sensor is used to measure the wave aberrations of the human eye by sensing the wave front emerging from the eye produced by the retinal reflection of a focused light spot on the fovea. Since the test involves the measurements of the local slopes of the wave front, the actual wave front is reconstructed by the use of wave-front estimation with Zernike polynomials. From the estimated Zernike coefficients of the tested wave front the aberrations of the eye are evaluated. It is shown that with this method, using a Hartmann-Shack wave-front sensor, one can obtain a fast, precise, and objective measurement of the aberrations of the eye.

[Study on phagocytosis of human neutrophils in diabetics]

Infection is one of the most common complications in diabetes mellitus (DM). The neutrophil plays an important role in the anti-infection mechanism. A comparative study on phagocytosis of P. Aeruginosa by human neutrophils in diabetic patients and healthy volunteers was carried out by means of the monolayer of neutrophils and ultrastructural observation in electronic microscopy. The results showed that the rates of phagocytosis, index of phagocytosis and rates of microbe lysis in DM group were much lower than those in normal controls (P < 0.01). The ultrastructure of neutrophils in diabetic patients became apparently abnormal during the process of neutrophil phagocytosis. The results demonstrated that the impairment in phagocytosis of neutrophils may be one of the causes of severe and repeated infection in diabetics.

Evaluating diffusion of light in the eye by objective means

PURPOSE

The authors have developed an index of diffusion that describes the relative spread of light inside and outside the region of image focus of the living human eye. It provides in numerical terms a measure of light scatter and can be used to characterize the optical deficit in eyes with age- and disease-related abnormalities of the anterior segment.

METHOD

An improved version of the double-pass method of examining the aerial image formed by reflection of the retinal image of a point source is employed, together with a new way of analyzing the image. Experimental estimation shows the contaminating effect of back scatter from the media and corneal reflection to be negligible. Measurements are objective and do not require any responses on the part of the patient. Data become available practically on-line.

RESULTS

Index of diffusion values were obtained on 13 patients and varied from 0.22 to 1.04, strongly tending to increase with age. They are rather robust to pupil size, exposure duration, and small amounts of defocus.

CONCLUSION

The index appears to provide a promising measure of optical performance of the media of the anterior segment of the eye, which might be useful in studying the effect of aging, injury, and disease.

Role of central vasopressin in cardiovascular regulation: effect of dehydration and sex

The present study was performed to evaluate the role of central vasopressin in cardiovascular regulation. First, a novel vasopressin V1 antagonist (OPC21268) was injected intracerebroventricularly in conscious rats. In water-deprived animals, the mean arterial blood pressure (MABP) and heart rate were significantly decreased compared with euhydrated control rats. There was, however, no significant difference in the concentration of vasopressin in the perfusate of cerebrospinal fluid between groups. Second, vasopressin was intracerebroventricularly injected in male and female homozygous Brattleboro rats. The increase in MABP was greater in males than in females. These results suggest that central vasopressin is involved in blood pressure regulation in pathophysiological states.

Social networks, social support, and mortality among older people in Japan

This study examined the effects of social networks and social support on the mortality of a national probability sample of 2,200 elderly Japanese persons during a three-year period. The direct and indirect effects of social relationships were assessed by using hazard rate models in conjunction with ordinary least squares regressions. Among the five measures of social relationships, social participation is shown to have a strong impact on mortality, and this effect remains statistically significant when other factors are considered. Social participation, social support, and feelings of loneliness are found to have indirect effects on the mortality of the Japanese elders through their linkages with chronic diseases, functional status, and self-rated health. On the other hand, marital status and social contacts are not shown to have statistically significant effects on the risk of dying, either directly or indirectly.

Metarhodopsin intermediates of the gecko cone pigment P521

Cone visual pigments are responsible for color vision. Using low-temperature spectroscopy and linear/logarithmic time scale flash photolysis, we studied the photochemistry of the cone visual pigment P521 from the lizard Gekko gekko. We found both meta I and meta II intermediates in this cone pigment; meta I absorbs at 480 nm, and meta II absorbs at ca. 380 nm. The formation of meta I is a fast process with a lifetime of 2.8 microseconds for the slow component (pH 6.70, 8.0 degrees C, 2% digitonin) compared to 2.1 microseconds for bovine rhodopsin under these conditions. The formation of meta II does not have single-exponential kinetics but can be better characterized by fast and slow components. High pH favors faster kinetics of meta II formation, but less is formed. The amount of meta II formed has a pKa of 8.7. The fast component of the meta II formation seems to have a somewhat lower pKa (e.g., 6.4). Temperature also affects meta II formation, with high temperature favoring a faster rate and larger amounts. The higher pKa of the meta I to meta II transition in gecko P521 compared to a rod pigment like bovine rhodopsin (pKa = 6.4) probably is due to a cysteine residue at position 211 in gecko rather than a histidine residue in bovine rhodopsin.

Stress, social support, and psychological distress among the Chinese elderly

This study examined the relationships among stress, social support, and depressive symptoms with data provided by a large representative sample (N = 2,721) of older adults who live in the People's Republic of China. Many Western investigators believe that elderly people respond to stressful experiences by mobilizing assistance from their significant others. However, recent American studies suggest that this may not always be true, and that when certain stressors arise, older adults may actually receive less support from significant others. The purpose of our study was to evaluate these competing views in a culturally diverse setting. The findings reveal that both perspectives have something to offer and that financial strain (i.e., one kind of stressor) may increase some kinds of assistance (i.e., economic support) at the same time that it erodes other types of support (e.g., emotional support).

Method for measuring visual resolution at the retinal level

To measure the intrinsic resolving capacity of the retinal and neural levels of vision, we devised a method that creates two lines with controllable contrast on the retina. The line separation can be varied at will, down to values below those achievable with conventional optical techniques. Implementation of the method with use of a He-Ne laser leads to a procedure that permits analysis of the performance of the human visual apparatus.

Structure and origin of middle ear corpuscles

The incidence, origin, structure and composition of middle ear corpuscles (MEC) were studied by dissection microscopy, by special stains and immunocytochemistry of histological sections and by transmission electron microscopy. MEC are formed within fibrous bands derived from transparent fibrous sheets which appear mainly in the mastoid antrum in the middle-aged and elderly. MEC are covered by a layer of epithelial cells with a normal basal lamina, and are largely composed of concentric layers of collagen which display alternating positive and negative birefringence. Pulmonary and prostatic corpora amylacea show a similar light microscopical structure and age relationship, but contain amyloid. It is suggested that MEC and the other bodies may be organized foci of epithelial basement membrane expansion perhaps derived from an in vivo counterpart of the "domes' seen in vitro in some monolayer epithelial cultures.

Changes in venous capacitance during prostaglandin E1-induced hypotension; comparisons with trinitroglycerin

The purpose of this study was to examine the effects of prostaglandin E1 (PGE1) on venous capacitance during controlled hypotension. Trinitroglycerin (TNG) was used as a control agent. In rats anesthetized with ketamine, mean arterial pressure was lowered to 70 mmHg and subsequently 50 mmHg by intravenous infusion of PGE1 or TNG. Venous capacitance was assessed before and during induced hypotension by measuring the mean circulatory filling pressure (MCFP). MCFP was measured after briefly arresting the circulation by inflating an indwelling balloon in the right atrium. MCFP was significantly decreased by PGE1 from 7.9 +/- 0.3 to 6.9 +/- 0.3 mmHg at mean arterial pressure of 70 mmHg and to 6.9 +/- 0.2 mmHg at mean arterial pressure of 50 mmHg. The decrease in MCFP by PGE1 at mean arterial pressure of 70 mmHg was not significantly different from TNG. However, the decrease in MCFP by PGE1 at mean arterial pressure of 50 mmHg was significantly less than that by TNG. The results suggest that the venous capacitance may be increased by PGE1 to a similar degree with TNG at doses to produce a comparable level of moderate hypotension, but the increase in venous capacitance may be less in PGE1 than TNG at doses to produce deep hypotension.

[The clinical use of steady-state flash visual evoked potentials]

The authors applied 30Hz flash stimuli to record steady-state flash visual evoked potentials (FVEP) and extracted the amplitudes and phases of the first and second harmonics as the characteristic value by discrete Fourier transform (DFT). 46 normal controls (89 eyes) and 78 patients (109 eyes) were detected and analysed by this method. The result showed that the characteristic values of the normal controls are significantly different in three age groups and showed the positive in 35 eyes with the optic never diseases (82.9%), 25 eyes with age-related macular degeneration (92%), and 9 eyes with retinal detachment involved macular (100%). It indicates the method is a sensitive index to evaluate the macular visual function. After preliminary observation, the visual acuities of postoperation were found above 0.4 in cataracts (28 eyes) or opacities (12 eyes) if preoperative FVEP were normal and non-complicated, or less than 0.4 if preoperative FVEP were abnormal. This suggests the method is one of the effective index to detect the postoperative vision of the media opacities. The advantages, disadvantages and the clinical applications were discussed.

Insitu nick translation, an alternative to cytogenetics in analyzing mutagen effects on human-cells

A chromosomal break indicates a double-stranded DNA break of the chromatin fiber. Cytogenetic observations can enumerate chromosome breaks but cannot detect single-stranded DNA breaks (nicks). When a high frequency of chromosomal breaks occurs in a cell population, whether spontaneously occurred or mutagen induced, a higher frequency of nicks is expected. In order to correlate these two type of DNA lesions, we used human lymphoblastoid lines known to be either hypersensitive or relatively resistant to the genotoxicity of bleomycin. The frequency of nicks was estimated by grain counts over interphase nuclei in autoradiographs following the technique of in situ nick translation. Good agreement was found between these two sets of data, viz, hypersensitive lines showed a high frequency of chromatid breaks as well as a high frequency of grain counts, and vice versa. These results suggest that the phenomenon of differential bleomycin sensitivity is genetically determined.

Stress and exercise among the Japanese elderly

This study seeks to replicate and extend research on the stress process by examining the relationships among stress, social support, physical exercise, and depressive symptoms with data provided by a recent nationwide survey of older adults in Japan. The findings reveal that more frequent physical exercise is associated with less psychological distress. Moreover, the data suggest that some (but not all) types of stressors tend to diminish the frequency of physical activity. Finally, and perhaps most important, the results reveal that social support tends to promote more frequent exercise. This can occur in two ways. First, more emotional support was related to better exercise habits. In addition, negative interaction was also associated with more frequent exercise, suggesting that informal social sanctions can foster positive health behaviors.

Patterns of nonresponse in a national survey of elderly Japanese

Data from a nationwide sample of older adults in Japan were analyzed to determine patterns of unit nonresponse. Maximum likelihood logistic regression analyses identified age, sex, geographic region, and urbanicity as significant predictors of response status. The probability of nonresponse was higher for men, persons living in certain regions, and those in large urban areas. Age had a curvilinear relationship with response status; the probability of nonresponse decreased from age 60 to age 70, and then increased again with the highest rates at the oldest ages. When nonrespondents were disaggregated into three different groups based on reason for nonparticipation (i.e., refusals, not-at-homes, other reasons), variation in the results was found. For example, while men were more likely than women to refuse an interview or be absent from home during the survey period, they were no more likely to not participate for other reasons. Use of different response rate calculations and a substitution sampling procedure were not found to seriously affect study results.