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Biomedical subjects

D R Jones

Publications and source records attributed to D R Jones.

At least 307 records · Page 17Linked to original sources
PubMed1983

Influence of ischemia and hypoxia on breathing in ducks.

We examined the influence of whole and lower body hypoxia and lower body ischemia on breathing in White Pekin ducks, Anas platyrhynchos, excluding pathways involving the carotid bodies. Carotid body denervated birds breathing 10 or 5% O2 developed a tachypnea after a latency of 30-100 s. The tachypnea was more pronounced with the more severe hypoxia, resulting in almost a doubling of minute ventilation (VE). Occlusion of the abdominal aorta in unanesthetized ducks produced immediate development of hypertension. Ventilation was unaffected for the 1st min; a tachypnea then developed rapidly and persisted for the duration of the occlusion resulting in a 25% increase in VE. After thoracic spinal section, all ventilatory responses to occlusion were eliminated. Experimental perfusion of the brain and single intact carotid body in unanesthetized ducks with hyperoxic blood during low O2 breathing (6-9% O2) resulted in tachypnea, also after a considerable latency. These results suggest that severe hypoxia can affect breathing in birds via pathways other than those involving the carotid bodies.

Animals↗
PubMed1983

Selective labeling of spiral ganglion and granule cells with D-aspartate in the auditory system of cat and guinea pig.

The present study sought to locate putative glutamatergic or aspartatergic pathways in the auditory system of cats and guinea pigs. We injected 0.06 to 3 mM D-[3H] aspartate (D-Asp) in the cochlear nucleus before preparation for light microscopic autoradiography. At short survival times (15 and 40 min) there was heavy labeling of astrocytic somata. Labeling patterns typical of cochlear nerve endings decorated neurons in the cochlear nucleus, e.g., cell bodies and dendritic trunks of octopus cells. Labeling patterns consistent with retrograde axonal transport by the parallel fibers of granule cells appeared in the molecular layer of the dorsal cochlear nucleus and in the external granular layer. Retrograde labeling of the cochlear nerve root fibers also occurred. Consistent with these results are companion biochemical findings on the rapidly dissected cochlear nuclei of guinea pigs. The dorsal, anteroventral, and posteroventral cochlear nuclei, each, evinced uptake of D-Asp. Subsequently, electrical stimulation of each nucleus released a portion of the accumulated amino acid. Most of this release probably came from synaptic endings. Another group of experiments compared autoradiographic localization of 0.06 to 3 mM D-Asp to that of horseradish peroxidase (HRP) 6 hr to 2 d after injections in the cochlear nucleus. Astroglial cell bodies were no longer labeled by D-Asp, but spiral ganglion cell bodies in the cochlea and granule cell bodies in the cochlear nucleus were. Perikarya of the periolivary and ventral cochlear nuclei projecting to the dorsal cochlear nucleus were labeled by HRP and not by D-Asp. Thus, comparisons with the HRP findings indicate that D-Asp labeling resulted from a selective retrograde transport. There was no evidence for a selective anterograde axonal transport. The present observations support the hypothesis that cochlear nerve fibers and granule cells may use L-glutamate and/or L-aspartate as a transmitter in the cochlear nucleus.

Animals↗
PubMed1983

The evolution and present status of mental health standards for selection of USAF candidates for space missions.

The mental health evaluation of the original Mercury astronauts was a prolonged, meticulous, research-oriented process involving testing and interviews to determine who was best qualified for space flight. The trend since then has been to simplify this evaluation, making it more subjective and clinically oriented. The goal is to identify candidates who are fully qualified, free of psychopathology, and who have a healthy motivation for space flight. The selection of nonpilots for duty as payload specialists introduces new factors--lack of previous exposure to dangerous situations, possible impact of new stresses on the family situation, and interrelationships between crew members. These factors can be included in determinations of individual candidates as being "fully qualified," rather than returning to the original "best qualified" standards, and affirmative qualities may be identified which mark candidates as "exceptionally well qualified." Validation of these evaluation procedures and criteria depends upon assessment of space crew members' performance on actual mission.

Aerospace Medicine↗
PubMed1983

Psychiatric assessment of female fliers at the U.S. Air Force School of Aerospace Medicine (USAFSAM).

There were 17 female fliers referred for evaluation to the Neuropsychiatry Branch, Clinical Sciences Division, of the USAF School of Aerospace Medicine, Brooks AFB, TX, between October 1976 and September 1982: five primarily for emotional reasons; seven primarily for somatic disorders and only secondarily for emotional symptoms; two for entry to the Airsickness Rehabilitation/Treatment protocol; and three for routine evaluation in preparation for possible future space flight. This number is too small for any sort of statistical analysis, but one emerging theme has clinical importance. A significant number of male fliers tend to see these female fliers in stereotyped roles--mother, potential sexual partner, little sister, daughter--and then respond to the assigned role rather than to a real person. Whether a woman accepts this projected role as egosyntonic or rejects it as egosyntonic, its existence may affect her real-life role. For example, one woman pilot reported that her instructors seemed to make allowances for her sex by expecting less of her than they did of her male colleagues, "carrying" her along as if she were a little sister. While such role-casting may be carried on subconsciously, its behavioral manifestations are real and may have the potential for affecting flight safety. This study represents an initial approach to the data in this area, and is intended to alert flight surgeons to the implications of such role-casting in the flight environment.

Aerospace Medicine↗
PubMed1982

Remarkable blood catecholamine levels in forced dived ducks.

Levels of circulating epinephrine (E) and nor-epinephrine (NE) were measured in duck blood before, during, and after forced dives which were extended close to the limit of underwater endurance. Both E and NE increased by, on occasion, three orders of magnitude. After surfacing, plasma catecholamine levels fell rapidly. The reason for this enormous amine release in forced dived ducks remains a matter of speculation.

Animals↗
PubMed1982

Simultaneous inference in epidemiological studies.

Some difficulties encountered in using and interpreting significance tests in both exploratory and hypothesis testing epidemiological studies are discussed. Special consideration is given to the problems of simultaneous statistical inference--how are inferences to be modified when many significance tests are performed on the same set of data? Although some partial solutions are available, greater emphasis on estimation methods and less use of and reliance on significance testing in epidemiological studies is more appropriate.

Epidemiology↗
PubMed1982

Control of diving responses by carotid bodies and baroreceptors in ducks.

The precise role of carotid body chemoreceptors and systemic baroreceptors in cardiovascular responses during experimental diving in ducks is controversial. The diving responses of chronically baroreceptor-denervated, chemoreceptor-denervated, and combined baroreceptor- and chemoreceptor-denervated White Pekin ducks, Anas platyrhynchos, were compared with those of intact and sham-operated birds. All three types of denervation elevated predive heart rates on average by 100-150 beats/min. During submergence, the cardiac rate of the barodenervates quickly dropped and after 60 s stabilized at levels similar to those of submerged intact ducks for the remainder of a 2-min dive. However, arterial blood pressure declined drastically in the barodenervates. Ducks without functional carotid bodies showed significant bradycardia during submergence, although heart rate only fell to the predive rate of intact animals. Birds with combined baroreceptor and chemoreceptor denervation exhibited the same degree of bradycardia as chemoreceptor denervates, and arterial blood pressure rose spectacularly during a dive. It is concluded that during experimental diving in ducks 1) cardiac responses are not baroreflexive in origin, 2) the major portion of bradycardia is due to stimulation of carotid body chemoreceptors, and 3) intact system baroreceptors appear essential for maintenance of blood pressure.

Animals↗
PubMed1982

Role of central and peripheral chemoreceptors in diving responses of ducks.

Using techniques of vascular isolation and subsequent perfusion we have investigated the effects of altering blood gas tensions, in the cerebral and carotid body circulations, on some cardiovascular responses to diving in unanesthetized ducks. After denervating the right carotid body, perfusion of the innervated left carotid body with hyperoxic blood significantly reduced diving bradycardia and reduced the increase in hindlimb vascular resistance (HLVR) in 1-min dives compared with dives in which the innervated carotid body was autoperfused. Denervation of systemic arterial baroreceptors reduced the fall in heart rate (HR) and increased the rise in HLVR in all dives. Cross-perfusion of the head, from a donor with blood of normal blood gas tensions, did not significantly affect HR or HLVR in 2-min dives compared with dives in which the head was autoperfused. however, cross-perfusing the cerebral circulation with blood of elevated PaCO2 caused significantly greater increases in HLVR than when high PaCO2 only affected the peripheral circulation. We conclude that peripheral chemoreceptors cause virtually all the bradycardia in the later stages of a dive but only about one-half the increase in HLVR, a significant contribution comes from the stimulation of central chemoreceptors with blood of high PaCO2.

Animals↗
PubMed1982

Effect of cardiovascular variables on hyperpnea during recovery from diving in ducks.

Control of hyperpnea during recovery from diving in unanesthetized White Pekin ducks, Anas platyrhynchos, was examined. Postdive minute ventilation (VE) increased five times regardless of the length of the preceding dive (1-4 min), although longer dives resulted in slower return of VE towards predive levels. Manipulation of arterial blood gases showed that both hypoxia and hypercapnia contributed to hyperpnea on emergence. Although chronic bilateral carotid body denervation depressed VE before and after diving, VE still increased four times after 1-min dives. Postdive hyperpnea was accompanied by dramatic elevations in heart rate, cardiac output, and the ventilation/perfusion ratio. However, artificially maintaining heart rate at abnormally low levels did not affect the postdive hyperpnea. In addition, postdive hyperpnea was unaffected by systemic arterial baroreceptor denervation. Postdive hyperpnea in ducks depends on blood gas changes occurring during a dive, yet a substantial part of the response is independent of input from carotid body chemoreceptors and the accompanying rises in heart rate and cardiac output.

Animals↗
PubMed1982

The effect of changes in blood oxygen-carrying capacity on ventilation volume in the rainbow trout (Salmo gairdneri).

1. Changes in ventilation volume (Vg) of rainbow trout caused by hypercapnia, hypoxia and anaemia were measured directly by collection of expired water. 2. Exposure to hypercapnic water (PCO2 range 0.5-2 kPa) increased Vg (by up to four times) by augmenting ventilatory stroke volume; breathing frequency remained constant. O2 added to the inspired water in maintained hypercapnia reduced Vg at all but the highest level of PCO2. 3. Vg increased when blood oxygen content was decreased by exposure to normoxic hypercapnia, but addition of O2 to the water increased blood oxygen content and Vg decreased. 4. When blood oxygen-carrying capacity was depressed by hypoxia or anaemia, Vg increased as it did during normoxic hypercapnia. 5. We suggest that ventilatory responses to low levels of hypercapnia, to hyperoxic hypercapnia, to hypoxia, and to anaemia in trout are related to changes in levels of blood oxygen content under these conditions.

Anemia↗
PubMed1982

Haematological findings in healthy and diseased rabbits, a multivariate analysis.

Haematological data from 94 diseased rabbits and 23 healthy adult rabbits were analysed statistically using principal components analysis and multiple discriminant function analysis. The 1st principal component accounted for 32% of the variation and was interpreted as showing total blood cellularity. This was decreased in the majority of diseased rabbits, principally due to anaemia, although in a few it was slightly increased possibly as a result of dehydration. The 2nd principal component (22% of the variation) had high positive loadings on monocyte and heterophil counts and weak negative loadings on the red cell characters. This component was interpreted as the response of the white blood cells to disease. When classification analysis was used to decide whether or not an animal was 'normal' the heterophil and lymphocyte counts alone provided almost as accurate an assessment as when all the blood parameters were taken into account. The role of these analyses in the diagnosis of disease is discussed.

Analysis of Variance↗
PubMed1981

Use of saffan in dogs.

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Alfaxalone Alfadolone Mixture↗
PubMed1981

Azotobacter keratitis.

Ten cases of Azotobacter keratitis were identified at the Baylor College of Medicine and Cullen Eye Institute, Houston, from 1972 to 1980. Azotobacter are large, pleomorphic, aerobic, Gram-negative rods of the family Azotobacteraceae. The genus comprises four species (A beijerinckii, A chroococcum, A paspali, and A vinelandii) that are found in soil and water throughout the world. To our knowledge, Azotobactger species have not previously been recognized as causing human, animal, or plant disease. On the basis of the similarity of the organisms, other cases of Azotobacter keratitis may have been identified erroneously as Moraxella species.

Adolescent↗
PubMed1981

Suicide in England and Wales: an analysis of 100 years, 1876-1975.

The variations in suicide mortality in England and Wales over a 100-year period (1876-1975) are explained by the development of a descriptive model. The model used in a stepwise linear regression using 5 variables including toxic gas production. The variables give a good description of the observed changes in suicide mortality. The limitations of the method and the data are discussed. Despite the limitations of the method, it can be concluded that toxic gas production affected total suicide mortality.

England↗