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Biomedical subjects

G Vance

Publications and source records attributed to G Vance.

6 recordsLinked to original sources
PubMed1994

Ocular manifestations of Hansen's disease.

A detailed ophthalmic evaluation including slitlamp biomicroscopy, measurement of corneal sensitivity using Cochet and Bonnet aesthesiometer, Schirmer's test and Goldmann applanation tonometry was carried out in 89 patients of Hansen's disease attending the leprosy clinic with or without ocular symptoms and willing to undergo eye evaluation. Thirty-one patients had lepromatous leprosy (8 with erythema nodosum leprosum), 56 patients had borderline disease (13 with reversal reactions) and 2 had tuberculoid disease. In addition to the well documented changes of lagophthalmos (6.7%), uveitis (7.3%) and cataracts (19%), we noted prominent corneal nerves in 133 eyes (74.7%), beaded corneal nerves in 19 eyes (10.7%), corneal scarring in 10 eyes (5.6%), corneal hypoaesthesia in 51 eyes (28%) and dry eye in 18 eyes (13%). Beaded corneal nerves and/or stomal infiltrates occurred mainly in the lepromatous group (75%). Ocular hypotony (IOP less than 12 mm Hg) was not seen more frequently in Hansen's as compared to age and sex matched controls with refractive errors or cataracts (33.7%, vs. 37.8%, p = 0.33). Our study highlights the primary corneal involvement with corneal neuropathy as the predominant feature of Hansen's disease.

Adolescent↗
PubMed1989

Some reflections on the phylogeny and function of the pineal.

The pineal gland is a universal feature of vertebrate organization and has been implicated in the control of rhythmic adaptations to daily and seasonal cycles. This paper considers three aspects of pineal function; the generation of a rhythmical endocrine signal (the nocturnal synthesis of melatonin) and the use of the signal in the regulation of circadian and photoperiodic functions. The shape of the nocturnal signal is determined by an interaction of afferent neural control and biochemical processes intrinsic to the pinealocyte. The nature of the effect of the signal upon circadian systems is unclear, and in adult mammals may not be a specific, direct influence upon the entrainment pathways of the oscillator. In the foetus, strong evidence exists for a physiological role of the maternal melatonin signal as a true internal zeitgeber, remnants of which may persist in the adult. Photoperiodic time measurement in adult and foetal mammals is critically dependent upon the melatonin signal. Indirect evidence indicates that several neural systems may be involved in the response to melatonin and consistent with this, a variety of central melatonin binding sites have been identified in the brain and pituitary. The intra-cellular actions of melatonin and the properties of melatonin responsive neural systems have yet to be identified, but in the context of photoperiodic time measurement, it is clear that the neural responses to melatonin are not dependent upon the circadian clock. The two central effects of melatonin; photoperiodic time measurement and circadian entrainment are probably mediated through completely separate mechanisms.

Animals↗
PubMed1987

Spinocerebellar ataxia: localization of an autosomal dominant locus between two markers on human chromosome 6.

Inherited spinocerebellar ataxias (SCA) are progressively degenerative neurological diseases. The primary site of degeneration is the cerebellar cortex--in particular, the Purkinje cells. In the present report, the SCA locus, inherited as an autosomal dominant trait in a large kindred, is localized to a region approximately 15 centimorgans telomeric of HLA-A on the short arm of chromosome 6.

Chromosome Mapping↗
PubMed1985

Coping with aversive stimulation in the neonatal period: quiet sleep and plasma cortisol levels during recovery from circumcision.

Measures of behavioral state and plasma cortisol were obtained on 80 healthy, full-term, 2-3-day-old, male newborns who were scheduled to be circumcised. To establish baseline or precircumcision levels, the newborns were observed, and behavioral state was recorded for the half hour prior to circumcision. Blood was sampled via heelstick for plasma cortisol determination at the end of this observation period. The newborns were then circumcised and assigned randomly to one of 4 postcircumcision, blood-sampling time-point groups. The time points were 30, 90, 120, and 240 min following the beginning of circumcision. Behavioral state was observed during circumcision and for the half hour prior to taking the second blood sample. The results showed a return to baseline cortisol levels sometime prior to 240 min, with data from an additional group of 10 newborns indicating that the return occurred by 150 min. Behavioral distress during circumcision was associated with elevations in plasma cortisol at 30 and 90 min. Quiet sleep was correlated negatively with plasma cortisol prior to circumcision, and significant increases in quiet sleep followed circumcision, with the greatest increase corresponding to the period of most rapid reductions in cortisol.

Adaptation, Psychological↗