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Biomedical subjects

C Murphy

Publications and source records attributed to C Murphy.

At least 253 records · Page 14Linked to original sources
PubMed1984

DNA sequence of the white locus of Drosophila melanogaster.

The DNA sequence of the white locus of Drosophila melanogaster is presented. This 14,100 base-pair sequence includes the region of the locus required for wild-type levels of expression and control of expression. We also report the sequence of a complementary DNA clone which established the position of the 3' end of the white RNA on this genomic sequence. The probable exon-intron structure of the gene has been predicted from the DNA sequence of the regions known to be represented in the RNA. The amino acid sequence of the protein which would be produced by translation of this RNA suggests that the white locus gene product may be a membrane protein. The DNA sequence rearrangements associated with seven insertion mutants (white-dominant-zeste-like (wDZL), white-spotted (wsp), white-honey (wh), white-zeste-mottled (wzm), white-apricot (wa), white-buff (wbf) and white-hd81b11 (whd81b11)), one deletion mutant (white-spotted 4 (wsp4)) and one internal duplication mutant (white-ivory (wi)) have been determined and positioned on the wild-type sequence. The positions of these insertions and those of previously characterized insertions associated with six other mutations suggest that some insertions within an intron may still allow the production of correctly spliced RNA, but affect the amount, and correspondingly the expression of the w locus.

Animals↗
PubMed1984

Trabecular meshwork cellularity in primary open-angle glaucoma and nonglaucomatous normals.

The trabecular meshwork cellularity (cells/unit tissue area) was compared in patients with primary open-angle glaucoma (POAG) with that of nonglaucomatous (NG) individuals. The NG specimens (n = 69) include specimens from the prenatal period (n = 14) as well as the postnatal period to age 98 years (n = 55). The glaucoma specimens (n = 49) covered a wide-range of ages (23-80 years) and were obtained at trabeculectomy (n = 31) or at autopsy (n = 18). Our results show that the trabecular cellularity in NG specimens decreases most rapidly and in a nonlinear manner in the late fetal period and for the first few years of postnatal life. This rapid decline in cellularity then slows down to proceed in a nearly linear manner for the remainder of the 98 years of life studied. The meshworks from patients with POAG have a lower cellularity than normals over the wide range of ages examined, but both types of specimens undergo similar declines in cellularity with age. Thus, the age-cellularity curves for both the NG and POAG specimens are parallel to each other. The loss of cells occurs in a gradient-like manner with the inner tissues being most affected and the outermost tissues least affected. A variety of statistical tests show that these changes in cellularity are highly significant and specific. These findings are compared to the loss of endothelial cells in the cornea and they are discussed in relation to the important clinical characteristics of POAG.

Adolescent↗
PubMed1984

Continuous recording of neck rotation: preliminary observations.

An instrument is described that allows continuous recording of neck rotation for periods of up to 12 hours. This allows analysis of how the neck actually is used rather than its range of positions on static testing. This technique will be helpful in evaluating the severity of disorders of the neck and the effectiveness of treatment.

Electronics↗
PubMed1984

Prenatal and postnatal growth of the human Descemet's membrane.

The origin, growth in thickness, and differentiation of Descemet's membrane was studied by light, electron microscopic, morphometric, and statistical methods in 67 specimens from 12 weeks of gestation to 98 years. Descemet's membrane is formed by three major processes: growth in thickness during the prenatal period, prenatal differentiation into a striated basement membrane, and growth in thickness during the postnatal period. The initial step is the synthesis of an ordinary basement membrane, which is very thin and quite different in appearance from the adult Descemet's membrane. Growth of the prenatal Descemet's membrane then proceeds by deposition of a series of similar "membrane units," which are stacked to form a lamellar structure consisting of at least 30 layers by the end of gestation. Second, during prenatal life, differentiation of the membrane leads to the formation of a striated structure through the gradual addition of short and thin cross-linking bridges separated by 110-nm intervals that are disposed in a plane perpendicular to the lamellae. The third process occurs in postnatal life when the membrane continues to grow in thickness by deposition of a nonstriated, nonlamellar material posterior to the striated prenatal layer. Regression analysis suggests that prenatal growth proceeds at a rapid but variable rate best described by a "sigmoid-like" function of age. Postnatal growth, in contrast, proceeds in a predominantly exponential manner but at a slower pace than in the prenatal period. The low variability and large size of our set of measurements make these data especially useful for comparisons with pathologic specimens.

Adolescent↗
PubMed1984

Prenatal and postnatal cellularity of the human corneal endothelium. A quantitative histologic study.

The authors studied the cellularity of the normal corneal endothelium by histologic methods in 56 specimens from 16 weeks of gestation to 98 years of age. Ten step-serial sections were taken from each specimen through the central 6 mm of the cornea, in an area measuring 1.8 mm. The number of nuclei were counted on each section and a ratio of the number of nuclei per 100 micron of endothelial length was determined. This ratio provides a measure of cell density that they call cellularity. There is a decrease in cellularity that proceeds in a nonlinear manner and at a very rapid rate during the prenatal period and for the first few years of life. Cell death or necrosis, which might have contributed to this apparent loss of cells, was not observed. Instead, this rapid change in cellularity is correlated with a concomitant change in corneal size. The authors' calculations show that cell division may play a minor role in the formation of the endothelium after the second trimester of fetal life as most of the cells present by birth already exist by this time. After the first few years of life, the rate of change in endothelial cellularity decreases to proceed in a linear manner for the rest of the near 100 years of life examined. This latter age-related decline in cellularity is probably due to the loss of 0.56% cells per year from the endothelial layer, since the cornea does not appear to change in size during this time. Statistical analysis of the authors' data shows that these results are highly significant.

Adult↗
PubMed1983

The musculature and pupillary response of the great horned owl iris.

There is considerable confusion in the literature regarding the nature of the musculature of the avian iris. The most commonly held view is that both the sphincter and dilator are striated. The iris of the Great Horned Owl (Bubo virginianus) has a complex iridial musculature consisting of three circumferential components (a myoepithelium, smooth muscle and striated muscle) and two radial components (a well-developed myoepithelium and a few striated fibers). On the basis of the anatomy and relative development of these components, and a quantitative analysis of the pupillary reflex, it is proposed that the circumferential striated muscle is the primary pupillary constrictor and radial myoepithelium is the primary dilator. The annular band of smooth muscle may play an important role in maintaining pupillary size.

Animals↗
PubMed1983

Age-related effects on the threshold, psychophysical function, and pleasantness of menthol.

Participants were 20 persons half of whom were 18 to 26 years of age (M = 21) and half of whom were over 65 years (M = 75). All were ambulatory, noninstitutionalized, and reported good to excellent health. The stimulus was menthol delivered in air to the nostrils. Threshold was measured using the up-down staircase method. Intensity and pleasantness were measured by magnitude estimation. The average threshold for the elderly participants was significantly higher than for young participants. The median slope of the intensity function was steeper by a factor of two for younger adults. The average pleasantness functions were steeper for the younger persons. Finally, although the younger adults found menthol less pleasant with repeated exposure, the elderly persons showed no effect of exposure. The results suggest that the average, healthy elderly person's odor/trigeminal world differs from that of the young adult. Further experiments are exploring the relative contributions of olfactory, trigeminal, and cognitive factors in producing this change.

Adolescent↗
PubMed1983

Age-related changes in the basement membrane of the human corneal epithelium.

An ultrastructural evaluation and morphometric analysis of the basement membrane of the normal human corneal epithelium in 45 specimens from subjects ranging in age from 17 weeks of gestation to 93 years was conducted. It was found that thickening of the corneal epithelial basement membrane takes place by two main processes: continued membrane deposition (forming unilaminar membranes) and membrane reduplication (forming multilaminar membranes). During the fetal period and for the first two decades of postnatal life, membrane thickening occurs exclusively by continued membrane deposition so that these unilaminar membranes increase in thickness by 3 nm each year. Membrane reduplication in focal areas after the age of 20 and with increasing frequency and greater involvement of the membrane thereafter was observed. Since anchoring fibrils and hemidesmosomes are important in the adhesion of the epithelium to Bowman's layer, we paid particular attention to these structures. We could find no relation between hemidesmosome content and the formation of reduplicated or multilaminar membranes. However, the anchoring fibrils become disrupted with increasing age, and the membrane thickness exceeds fibril length in some specimens. It is proposed that this phenomenon effectively blocks linkage between the anchoring fibrils and Bowman's layer. The evidence for cell injury and death as a promoter of membrane reduplication was compared to the evidence for a primary deterioration of the basement membrane.

Aging↗
PubMed1982

Localization of human immunoglobulin kappa light chain variable region genes to the short arm of chromosome 2 by in situ hybridization.

The genes for human immunoglobulin kappa light chains have been localized in normal lymphocyte and fibroblast chromosomes by in situ hybridization of probes from cloned DNA fragments of the kappa variable region locus. The localization was achieved by counting grains (after autoradiography) over chromosomes in a number of karyotypes. The variable region gene probes hybridized in a cluster on a region of the chromosome 2 short arm close to the centromere (2cen leads to p12). This location was confirmed in lymphocytes from a balanced translocation carrier 46XXt (2; 16) (q13; q22). Our results show that human kappa light chain genes are located in the region of the break point observed in specific chromosomal translocations associated with Burkitt lymphoma.

Binding Sites, Antibody↗
PubMed1981

Anaemia in old age: a study of prevalence and causes.

A study of the prevalence and causes of anaemia in 559 randomly selected people aged 65 years and over living in their own home, in residential homes or in hospitals was made. In the population 65 years and over 7.1 percent were found to have a haemoglobin level less than 120 g/l and 2.5 percent a haemoglobin level less than 110/gl. The majority who were anaemic suffered from multiple and chronic diseases. The dietary intake of the anaemic was similar to those with a normal haemoglobin. In women aged 80 years or more, the haemoglobin level decreased significantly with age. Women had lower haemoglobin levels than men.

Age Factors↗
PubMed1981

Chromosomal localization of a single copy gene by in situ hybridization--human beta globin genes on the short arm of chromosome 11.

1. The localization of the beta globin genes by in situ hybridization to fixed chromosomes is described. 2. The probe used was a [3H]cRNA copy of a genomic clone containing in total 4.4 kb of DNA and including the beta globin gene. 3. The evidence for the localization of the gene comes from three pieces of data. (a) Chromosome 11 is labelled to double the extent expected if the grains were randomly distributed, (b) the extra grains above background are clustered on the short arm of 11 close to the centromere, and (c) the absolute number of grains observed is very close to that predicted for a probe of that length by comparison with ribosomal genes. The localization is in agreement with that obtained by other methods. 4. This method could be extended to any gene for which a genomic clone containing at least 5 kb of single copy DNA is available.

Chromosome Mapping↗
PubMed1981

Problems of families caring for Alzheimer patients: use of a support group.

An eight-week support group program was conducted for 15 members of the families of Alzheimer patients still living at home. It became clear that caring for an Alzheimer patient at home created tremendous practical, psychologic and social problems for family members. Frequently discussed problems included lack of support and information from physicians, poor understanding of the disease, depression, a trapped feeling, anger and fear about the patient's behavioral problems, isolation, and the caretaker's loss of self-identity. Group participation was especially beneficial for spouses who functioned as primary care providers. It increased their understanding of the disease, made them feel more supported and less isolated, and helped them resolve some of the feelings created by the illness. It also helped spouses to become more aware of their own needs and to regain some self-identity in relation to the patient. Such family support programs offer a way to strengthen the emotional well-being and treatment skills of the care-providing family and are an important aid to treatment in Alzheimer's disease.

Aged↗