Brain-tissue accumulation of fluorescent age pigments in four poeciliid fishes (cyprinodontiformes) and the estimation of "biological age"

The concept of an intrinsic "biological age" or "physiological age" is very important in comparative ecological and evolutionary studies, but its implementation has been problematic. Although many authors have discussed the importance of intrinsic measures of age over the past 75 years, only Reiss (1989 ) has proposed an operational definition in terms of cumulative metabolism; however, Reiss' measure cannot be easily applied to assessing the age of individual organisms. Measurement of the level of accumulation of fluorescent age pigments (particularly lipofuscins) in post-mitotic tissues, which seems to occur at a rate proportional to cumulative metabolism, in principle provides a mechanism for estimating the biological age of individual organisms. This study has shown that brain-tissue FAP levels vary in direct proportion to chronological age and body size within four species of poeciliid fishes, and has documented interspecific differences in rate of accumulation of fluorescent age pigments, differences that seem to be a function of the degrees of relatedness. Rather than proposing that FAP level by itself be used as a measure of biological age, however, I propose that it be used in conjunction with other estimates, such as chronological age and body size, to derive a composite "age factor."     

Mortality of persons with developmental disabilities after transfer into community care: a 1996 update

More than 2,000 persons with developmental disabilities have recently been transferred from California institutions into community care. Using data on 1,878 clients moved between April 1993 and December 1995, Strauss et al. (1998) found a corresponding increase in mortality rates. In the present report we update that study by analyzing 1996 data. There were 36 deaths, an 88% increase in risk-adjusted mortality over that expected in institutions, p < .01. We again found that persons transferred later were at higher risk than those moving earlier, even after adjustment for differences in risk profiles. In the highest functioning group, the community mortality rate was tripled. Death certificate information was also analyzed.     

Effect of increased atmospheric pressure on radial keratotomy

PURPOSE: To evaluate the effect of increased atmospheric pressure on visual acuity in patients who have had radial keratotomy (RK). SETTING: Long Beach Memorial Medical Center, Long Beach, California, USA. METHODS: This controlled clinical study comprised 4 eyes that had RK and 4 control eyes that were age and sex matched. All patients had prehyperbaric chamber examinations consisting of manifest and cycloplegic refractions, intraocular pressure (IOP), keratometry, and corneal pachymetry. They were then placed into the hyperbaric chamber for 1 hour. Immediately after the patients were removed from the chamber, the examinations were performed again. RESULTS: No statistically significant changes in visual acuity, refractive error, IOP, keratometry, or pachymetry occurred in the 2 groups. CONCLUSION: The results of this study indicate that, unlike at high altitudes, RK is stable at increased atmospheric pressure. This suggests that RK patients can engage in recreational scuba diving without encountering deleterious visual changes.     

Inflammatory mechanisms in Alzheimer's disease

In recent years many studies have indicated an involvement of inflammatory mechanisms in Alzheimer's disease (AD). Acute-phase proteins such as 1-antichymotrypsin and c-reactive protein, elements of the complement system, and activated microglial and astroglial cells are consistently found in brains of AD patients. Most importantly, also cytokines such as interleukin-6 (IL-6) have been detected in the cortices of AD patients, indicating a local activation of components of the unspecific inflammatory system. Up to now it has remained unclear whether inflammatory mechanisms represent a primary event or only an unspecific reaction to brain tissue damage. Therefore, we investigated whether IL-6 immunoreactivity could be found in plaques prior to the onset of neuritic changes, or whether the presence of this cytokine is restricted to later stages of plaque pathology. we confirmed our previous observation that IL-6 is detectable in a significant proportion of plaques in the brains of demented patients. In AD patients IL-6 was found in diffuse plaques in a significant higher ratio as would have been expected from a random distribution of IL-6 among all plaque types. This observation suggests that IL-6 may precede neuritic changes, and that immunological mechanism may be involved both in the transformation from diffuse to neuritic plaques in AD and in the development of dementia.     

Why is the Doppler pressure gradient higher than the one measured by catheter?]

Hemodynamic assessment of aorto-iliac occlusive disease is necessary for successful arterial reconstruction of the legs. Various methods have been proposed and the "pull-through" intra-arterial pressure measurement method is accepted as the best standard. The pressure readings, however, seemed to depend on the intraluminal position of the catheter. To explain these observations and make a comparison between the Doppler method and the "pull-through" method, we have studied center-line velocity changes at the stenosis throat by Doppler ultrasound, and axial and lateral pressure gradients using pressure transducers, mounted 10 mm and 40 mm downstream of short (4 mm) and long (40 mm) axisymmetric sharp-edged model stenoses having cross sectional reduced areas of 64%, 84%, 91%, and 96%. Axial manometric pressures measured 10 mm after the throat of 84% stenosis were more than twice as high as the lateral pressures. There was no significant difference between axial and lateral pressures measured 40 mm downstream from throat. This pressure distribution has important clinical relevance. Mean and peak pressure gradients for both the Doppler method and manometric measurements were compared. Measurements with Doppler method and manometric measurements, indicated that mean pressure gradients (r = 0.98; SEE = +/- -2.4 mmHg) correlate better than peak pressure gradients (r = 0.90; SEE = +/- 16.5 mmHg). Doppler gradients were higher than manometer gradients. Overestimation was 13% for mean pressure gradients, and ranging from 10% to 150% for peak pressure gradients. Explanation for the difference between mean Doppler and catheter gradient may be the pressure recovery occurring in the relaminarized poststenotic regions.     

Awareness of illness in schizophrenia

This article reviews the literature on "poor insight" or unawareness of illness in schizophrenia. A large body of knowledge representing several different perspectives on insight has developed. This work can be divided into three broad categories, suggesting an important role for insight in the phenomenology, pathophysiology, and treatment of schizophrenia. The argument is made here that many of the self-awareness deficits observed in schizophrenia are of diagnostic significance, are neurally based, and are indispensable in guiding treatment decisions. In addition, this article proposes guidelines for assessing unawareness of illness in schizophrenia and discusses the relevance of such deficits to the diagnosis of schizophrenia.     

Limited capacity for the removal of O6-methylguanine and its regeneration in a human lymphoma line

The Raji human lymphoma line is able to remove O⁶-methylguanine(O⁶MeG) lesions introduced by treatment of cells with N-methyl-N'-nitro-N-nitroso-guanidine(MNNG). The reaction has a rapid phase in which 40% of theO⁶MeG is removed in the first 10 min. The capacity of cellsfor rapid O⁶MeG removal is limited and is saturated at concentrationsof MNNG which do not saturate the systems removing 3-methyladenine.Pretreatment of cells with MNNG inhibits their ability to removeO⁶MeG produced by a subsequent dose given after 2 h. Treatmentwith N-ethyl-N'-nitro-N-nitrosoguanidine (ENNG) is effectivein diminishing cellular capacity for O⁶MeG removal, and cellsunable to remove O⁶MeG and sensitive to the cytotoxic effectsof MNNG are also more sensitive to ENNG than their removal competentcounterparts. Regeneration of the ability to remove O⁶MeG requiresincubation of cells for periods > 24 h. The O⁶MeG removalsystem is similar to that found in adapted Escherichia colialthough the capacity of the Raji lymphoma line is much lowerthan that of the induced bacteria per unit of DNA.