Expression of collagen and elastic fibers in duct-ligated submandibular glands of mice

Atrophy of salivary glands may occur by ductal obstruction caused by calculus, infection or neoplastic processes, or as consequence of systemic diseases and aging. In the present work, we have used histochemical methods to study the expression of elastic and collagen fibers during experimental atrophy of the submandibular gland of mice. Glandular atrophy was accompanied by a rapid increase in collagen deposition in both septal and intralobular regions. The expression of elastic fibers was not significantly altered during atrophy; a discrete increase of elastic fibers was noted only around ductal structures. The results showed that experimental ductal obstruction is a useful in vivo model to study molecular events that take part in the remodeling of the extracellular matrix during atrophy of salivary glands.     

The complications of immobility in the elderly stroke patient.

BACKGROUND: Approximately 500,000 persons in the United States suffer a stroke each year; the majority of these individuals are 65 years of age or older. The neurological impairment occurring as the result of stroke can lead to both acute and chronic disability. Further medical complication and disability are often the result of immobility-related illness that occurs while the patient is still in the hospital. METHODS: A MEDLINE search for articles published from 1980 to 1990 was made using the key words immobilization and stroke rehabilitation. The bibliographies of these articles, key rehabilitation and geriatric textbooks, the bibliographies of these textbooks, and the authors' personal files were also sources of information. RESULTS AND CONCLUSIONS: Immobility-related medical complication and disability can be substantially reduced by identifying risk factors and applying preventive measures. As long-term providers of medical care, family physicians are in a position to devise a preventive care plan for immobility-related disability and to appreciate the beneficial effects of such a plan on patient outcome.     

Chemical protective clothing standard test method development: Part II. Degradation test method

A "round-robin" interlaboratory evaluation of a proposed American Society for Testing and Materials (ASTM) standard test method was conducted for measuring the resistance of chemical protective clothing materials to degradation by liquid chemicals. The objective of this project was to determine the relative precision of the method and, where appropriate, recommend modifications that would improve reliability. In the round-robin format, eight laboratories used the proposed method to test each of five protective clothing materials against five liquid chemicals that are widely used commercially. The resulting data revealed that the proposed test method was not stringent enough to generate acceptable levels of accuracy and precision. Both intra- and interlaboratory standard deviations showed a high degree of variability in changes for the three physical properties evaluated. Changes in the method were identified which, if implemented, should improve accuracy and precision considerably.     

Sparse-sampling of gratings in the visual cortex of strabismic amblyopes

Strabismic amblyopes show losses in positional acuity that cannot be explained by their resolution or contrast sensitivities. One hypothesis for these losses is a reduction in the density of cortical neurons that are driven by the amblyopic eye (cortical undersampling). The question this study addressed was whether the foveal representation of the amblyopic eye is undersampled in the cortex of strabismic amblyopes. In order to assess spatial sampling psychophysically, we recorded the perceived orientation of a stationary grating as a function of grating orientation and frequency in three strabismic amblyopes. To ensure high retinal contrast, the grating was imaged on the fovea of each observer using a laser interferometer. We found that the strabismic amblyopes misperceived the orientation of the grating at spatial frequencies that are a factor of two to six lower than the sampling frequency of the foveal cones. Since the retina and LGN in strabismic amblyopes are presumably normal, this result suggests sparse cortical sampling in the foveal representation of the amblyopic eye. Undersampling by cortical neurons may contribute to the spatial distortions present in strabismic amblyopic eyes.     

The impact of support for black adolescent mothers

This exploratory study focuses on the association between social support and adolescents' responses to early motherhood. Subjects are 64 Black adolescent mothers in three groups: high school attenders, participants in the Baltimore City Public Schools Infant Parent Program and dropouts from school. Structured interviews are used to assess the young mothers' emotional stress as well as the amounts, sources, and kinds of support available. Self esteem and sense of control were assessed via standardized instruments. Respondents averaged 16.27 years of age when their children were born; at the time of the interview, ages of the mothers ranged form 14 to 19 years. 50.7% had completed school or were enrolled; 66% were working, typically in part time, work study type programs. Of the heads of their households, 40.3% were employed or receiving Social Services payments, 7.7% held technical jobs with the majority in the skilled or unskilled blue collar category. The children ranged in age from 2 months to 2 years. A major finding was that support from individuals is related to a decrease in stress and an increase in self esteem. The results are discussed in relation to the growing body of research documenting the impact of such support on maternal role performance.     

Molecular characterization of the transition to mid-life in Caenorhabditis elegans

We present an initial molecular characterization of a morphological transition between two early aging states. In previous work, an age score reflecting physiological age was developed using a machine classifier trained on images of worm populations at fixed chronological ages throughout their lifespan. The distribution of age scores identified three stable post-developmental states and transitions. The first transition occurs at day 5 post-hatching, where a significant percentage of the population exists in both state I and state II. The temperature dependence of the timing of this transition (Q ₁₀?~?1.17) is too low to be explained by a stepwise process with an enzymatic or chemical rate-limiting step, potentially implicating a more complex mechanism. Individual animals at day 5 were sorted into state I and state II groups using the machine classifier and analyzed by microarray expression profiling. Despite being isogenic, grown for the same amount of time, and indistinguishable by eye, these two morphological states were confirmed to be molecularly distinct by hierarchical clustering and principal component analysis of the microarray results. These molecular differences suggest that pharynx morphology reflects the aging state of the whole organism. Our expression profiling yielded a gene set that showed significant overlap with those from three previous age-related studies and identified several genes not previously implicated in aging. A highly represented group of genes unique to this study is involved in targeted ubiquitin-mediated proteolysis, including Skp1-related (SKR), F-box-containing, and BTB motif adaptors.