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Biomedical subjects

G Jones

Publications and source records attributed to G Jones.

At least 181 records · Page 10Linked to original sources
PubMed1998

Intraspecific responses to distress calls of the pipistrelle bat, Pipistrellus pipistrellus

Responses of the vespertilionid bat Pipistrellus pipistrellus to five recently caught conspecifics confined to a wire-mesh cage, at distances of 50 and 5 m from their roosts, were recorded on 12 separate evenings at three roosts during pregnancy and lactation. When bats were confined 50 m from their roost, an almost 20-fold increase in the number of bats that passed across an open site around the cage was recorded and the strength of response (number of bat passes) increased with time. When the bats were 5 m from the roost there was an 80-fold increase in bat activity above the cage. Playbacks of recorded distress calls produced by single hand-held bats resulted in a more than three-fold increase in bat passes, but the response waned rapidly. The distress calls of recently caught P. pipistrellus were generally similar to those of individuals from the same colony held for longer in captivity, and differences in distress calls between two of the three colonies studied probably reflect differences in the physiological states of recorded bats, rather than the existence of colony-specific vocalizations. Distress calls probably function in attracting conspecifics which perform mobbing behaviour as an anti-predator response. Copyright 1998 The Association for the Study of Animal Behaviour Copyright 1998 The Association for the Study of Animal Behaviour.

Journal Article↗
PubMed1998

Foreign bodies in the eye.

'I think I have got something in my eye.' This statement is one of the most common that patients make in any A & E department. For the nurse at triage, it is the beginning of an investigation that should establish a number of important historical facts: 1. How painful is the eye? 2. Is this foreign body of a high or low velocity? 3. What is the foreign body: dust, wood, metal, glass? 4. Was the patient wearing spectacles or contact lenses? 5. Has there been any alteration in the patients vision/sensitivity to light? Establishing these important historical facts will help the nurse determine the likelihood of this injury being a minor or major problem.

Conjunctiva↗
PubMed1998

Cytogenetics for the model system Arabidopsis thaliana.

A detailed karyotype of Arabidopsis thaliana is presented using meiotic pachytene cells in combination with fluorescence in situ hybridization. The lengths of the five pachytene bivalents varied between 50 and 80 microns, which is 20-25 times longer than mitotic metaphase chromosomes. The analysis confirms that the two longest chromosomes (1 and 5) are metacentric and the two shortest chromosomes (2 and 4) are acrocentric and carry NORs subterminally in their short arms, while chromosome 3 is submetacentric and medium sized. Detailed mapping of the centromere position further revealed that the length variation between the pachytene bivalents comes from the short arms. Individual chromosomes were unambiguously identified by their combinations of relative lengths, arm-ratios, presence of NOR knobs and FISH signals with a 5S rDNA probe and chromosome specific DNA probes. Polymorphisms were found among six ecotypes with respect to the number and map positions of 5S rDNA loci. All ecotypes contain 5S rDNA in the short arms of chromosomes 4 and 5. Three different patterns were observed regarding the presence and position of a 5S rDNA locus on chromosome 3. Repetitive DNA clones enabled us to subdivide the pericentromeric heterochromatin into a central domain, characterized by pAL1 and 106B repeats, which accommodate the functional centromere and two flanking domains, characterized by the 17 A20 repeat sequences. The upper flanking domains of chromosomes 4 and 5, and in some ecotypes also chromosome 3, contain a 5S rDNA locus. The detection of unique cosmids and YAC sequences demonstrates that detailed physical mapping of Arabidopsis chromosomes by cytogenetic techniques is feasible. Together with the presented karyotype this makes Arabidopsis a model system for detailed cytogenetic mapping.

Arabidopsis↗
PubMed1998

A comparison of morbidity from bilateral, unipedicled and unilateral, unipedicled TRAM flap breast reconstructions.

A large series of women who had undergone bilateral, pedicled TRAM flap reconstructions were compared with women who had had unilateral, unipedicled TRAM flap procedures to determine whether a bilateral TRAM flap breast reconstruction had significant additional morbidity. The records of all women who underwent either a bilateral or unilateral pedicled TRAM flap breast reconstruction through the Emory Clinic from 1987 to 1994 (n = 257) were retrospectively analyzed with respect to general, breast (fat necrosis, flap loss, and cellulitis), and abdominal (hernia, skin loss, and cellulitis) complications. By using logistic regression, risk factors for these complications were determined. The incidence of fat necrosis and partial flap loss was not significantly different among bilateral patients compared with patients with unilateral TRAM reconstructions (10.0 percent versus 12.6 percent, p = 0.64 and 3.8 percent versus 5.5 percent, p = 0.74, respectively). The rate of hernia formation in the bilateral TRAM flap patients (5.4 percent) was similar to that of unilateral patients (3.9 percent, p = 0.80). Significant factors for any complication in both patient populations included obesity, smoking, and prior irradiation. The type of breast reconstruction was not a significant factor for any breast or donor-site complication. A bilateral TRAM reconstruction showed a weak association with general complications. Review of the Emory Clinic experience with unilateral and bilateral pedicled TRAM flap reconstructions from 1987 to 1994 was able to detect no significant additional rate of complications for bilateral pedicled TRAM flap breast reconstructions compared with unilateral unipedicled TRAM flap procedures.

Age Factors↗
PubMed1998

Allelic variation in the vitamin D receptor, lifestyle factors and lumbar spinal degenerative disease.

OBJECTIVE: To describe the relation between spinal degenerative disease, allelic variation in the vitamin D receptor gene, and lifestyle factors in a population-based association study. METHODS: Random population-based sample of 110 men and 172 women over 60 years of age participating in the Dubbo Osteoporosis Epidemiology Study who had spinal radiographs (performed according to a standardised approach), assessment of lifestyle factors, bone densitometry as well as blood taken for genotyping. RESULTS: Spinal degenerative disease of varying severity was common in this sample. Multivariate analysis of genetic and lifestyle factors simultaneously strengthened the statistical significance of each indicating the presence of additive gene environment interaction. Allelic variation in the vitamin D receptor gene was associated with severity of osteophytosis (adjusted OR "TT" v "tt" 0.41, 95% CI 0.17, 0.97), presence of disc narrowing (adjusted OR "TT" v "tt" 0.45, 95% CI 0.20, 0.99) and weakly with presence of osteophytosis (adjusted OR "TT" v "tt" 0.47, 95% CI 0.19, 1.16) but not with severity of disc narrowing (OR "TT" v "tt" 1.05, 95% CI 0.40, 2.72) or apophyseal arthritis (OR "TT" v "tt" 0.63, 95% CI 0.24, 1.59). Adjustment for femoral neck bone density did not change these findings suggesting that the association is not mediated through bone density. Presence and severity of spinal degenerative disease increased with age at all sites. Current smoking increased both the presence (adjusted OR 9.70, 95% CI 2.08, 45.1) and severity (adjusted OR 2.91, 95% CI 1.16, 9.03) of spinal osteophytosis with intermediate values for past smokers. Severity of osteophytosis was also independently associated with body mass index and quadriceps strength consistent with a contributory effect of physical loading. CONCLUSIONS: In this elderly sample, both genetic and lifestyle factors were associated with the presence and severity of spinal degenerative disease. There were site specific differences in associations at the spine, which may be because of misclassification of disease status or may indicate possible environmental and genetic differences in the pathophysiology of spinal degenerative disease. Further studies are required to confirm these findings in different population samples and to further explore potential aetiological mechanisms particularly gene environment interaction.

Aged↗
PubMed1998

Current understanding of the molecular actions of vitamin D.

The important reactions that occur to the vitamin D molecule and the important reactions involved in the expression of the final active form of vitamin D are reviewed in a critical manner. After an overview of the metabolism of vitamin D to its active form and to its metabolic degradation products, the molecular understanding of the 1alpha-hydroxylation reaction and the 24-hydroxylation reaction of the vitamin D hormone is presented. Furthermore, the role of vitamin D in maintenance of serum calcium is reviewed at the physiological level and at the molecular level whenever possible. Of particular importance is the regulation of the parathyroid gland by the vitamin D hormone. A third section describes the known molecular events involved in the action of 1alpha,25-dihydroxyvitamin D3 on its target cells. This includes reviewing what is now known concerning the overall mechanism of transcriptional regulation by vitamin D. It describes the vitamin D receptors that have been cloned and identified and describes the coactivators and retinoid X receptors required for the function of vitamin D in its genomic actions. The presence of receptor in previously uncharted target organs of vitamin D action has led to a study of the possible function of vitamin D in these organs. A good example of a new function described for 1alpha,25-dihydroxyvitamin D3 is that found in the parathyroid gland. This is also true for the role of vitamin D hormone in skin, the immune system, a possible role in the pancreas, i.e., in the islet cells, and a possible role in female reproduction. This review also raises the intriguing question of whether vitamin D plays an important role in embryonic development, since vitamin D deficiency does not prohibit development, nor does vitamin D receptor knockout. The final section reviews some interesting analogs of the vitamin D hormone and their possible uses. The review ends with possible ideas with regard to future directions of vitamin D drug design.

Amino Acid Sequence↗
PubMed1998

Bone mass in prepubertal children: gender differences and the role of physical activity and sunlight exposure.

Retrospective studies have suggested that the prepubertal years may be an important window of opportunity to increase bone mass, but there have been few direct studies and little exploration of gender differences in this age group. In this study, we report the associations among physical activity measures, sunlight exposure, body composition, and bone mass in 8-yr-old children. We studied 330 children in 1996 (115 girls and 215 boys; response rate, 60%) who had previously taken part in a cohort study of cot death in 1988. They had measurement of anthropometrics (height, weight, and body composition), sunlight exposure (by questionnaire), and physical activity [questionnaire, muscle strength by dynamometry, and bicycle ergometric physical work capacity at a pulse of 170 beats/min (PWC170)]. Bone mineral density (BMD) was assessed at the spine, femoral neck, and total body by a Hologic QDR2000 densitometer. In females only, PWC170 [hip, 2.4%/quartile (95% confidence interval (CI), 0.3-4.5); spine, 1.7%/quartile (95% CI, 0.0-3.4); size adjusted] was associated with BMD, whereas in males only, BMD was associated with both sports participation (hip, 4.2% (95% CI, 1.1-7.3); spine, 4.3% (95% CI, 0.9-7.7)] and muscle strength [hip, 1.7%/quartile (95% CI, 0.0-3.4); but not spine; size adjusted]. Winter sunlight exposure was associated with BMD in girls [hip, 2.9%/category (95% CI, 0.7-5.0); spine, 3.6%/category (95% CI, 1.4-5.8)], but not in boys [hip, 0.3%/category (95% CI, -1.4 to +2.0); spine, 1.4%/category (95% CI, -0.7 to +3.5)]. Males and females were very similar in body size. However, males had higher size-adjusted BMD at the hip (9.6%; 95% CI, 6.9-14), whereas females had higher size-adjusted BMD at the spine (3.2%; 95% CI, 0.8-5.6%). In conclusion, this study has suggested that physical activity and exposure to sunlight are important in the bone mineralization of prepubertal male and female children. The magnitude of both gender and environmental differences in bone mass in this age group is substantial, suggesting that modification at this stage of life may influence peak bone mass and possibly fracture risk in later life.

Body Composition↗
PubMed1998

Unique 24-hydroxylated metabolites represent a significant pathway of metabolism of vitamin D2 in humans: 24-hydroxyvitamin D2 and 1,24-dihydroxyvitamin D2 detectable in human serum.

We have produced evidence for a new metabolic pathway for vitamin D2 in humans involving the production of 24-hydroxyvitamin D2 (24OHD2) and 1,24-dihydroxyvitamin D2 [1,24-(OH)2D2]. These metabolites were produced after either a single large dose (10(6) IU) of vitamin D2 or repeated daily doses between 10(3) and 5 x 10(4) IU. We developed assay systems for the metabolites in human serum and showed that in some chronically treated patients, the concentration of 1,24-(OH)2D2 equalled that of 1,25-(OH)2D2 at about 100 pmol/L. The metabolites were identified by high performance liquid chromatography with diode array spectrophotometry for 24OHD2 and by high resolution gas chromatography-mass spectrometry for 1,24-(OH)2D2. We show that 1,24-(OH)2D2 synthesis can be stimulated by PTH, indicating a renal origin for this metabolite and postulate that it is formed from 24OHD2, which may be synthesized in liver. We conclude from this study that vitamin D2 gives rise to two biologically active products, 1,24-(OH)2D2 and 1,25-(OH)2D2, and that 1,24-(OH)2D2 could be an attractive naturally occurring analog of 1,25-(OH)2D3 for clinical use.

Chromatography, High Pressure Liquid↗
PubMed1998

Characteristics and composition of peanut oil prepared by an aqueous extraction method.

Peanut is one of the crops being tested for NASA's Advanced Life Support (ALS) program for future long-duration human space missions. The ALS program is developing an integrated system for biomass (food, oxygen) production and resource recycling. Oil will be used mainly for cooking and its availability is important for food preparation. Peanut seeds contain 40-50% oil and hence are considered an excellent source of oil. In the ALS environment, a simple, compact, and energy-efficient system is needed. The feasibility of such a method, peanut oil preparation by water extraction, was investigated. The results indicated the important processing conditions to be: a peanut particle size of 0.02 cm or less, a pH of 4, simmering for 20 min plus churning at 65 degrees C for a few hours, and a centrifugation at 6000 x gn to separate the oil. The oil recovery yield was about 80%. The saponification value, specific gravity, refractive index, and viscosity were similar to that of commercial peanut oil except the color was lighter for the water-extracted oil. Gas and thin-layer chromatographic analyses showed that fatty acid and lipid profiles were similar to the commercial peanut oil. The only difference observed was that the oil prepared by the aqueous method had lower linoleic and higher oleic acids than the commercial peanut oil. The oil prepared by this aqueous method appeared to be of high quality.

Arachis↗
PubMed1998

Consumer acceptance of vegetarian sweet potato products intended for space missions.

Sweet potato is one of the crops selected for NASA's Advanced Life Support Program for potential long-duration lunar/Mars missions. This article presents recipes of products made from sweet potato and determines the consumer acceptability of products containing from 6% to 20% sweet potato on a dry weight basis. These products were developed for use in nutritious and palatable meals for future space explorers. Sensory evaluation (appearance/color, aroma, texture, flavor/taste, and overall acceptability) studies were conducted to determine the consumer acceptability of vegetarian products made with sweet potato using panelists at NASA/Johnson Space Center in Houston, TX. None of these products including the controls, contained any ingredient of animal origin with the exception of sweet potato pie. A 9-point hedonic scale (9 being like extremely and 1 being dislike extremely) was used to evaluate 10 products and compare them to similar commercially available products used as controls. The products tested were pancakes, waffles, tortillas, bread, pie, pound cake, pasta, vegetable patties, doughnuts, and pretzels. All of the products were either liked moderately or liked slightly with the exception of the sweet potato vegetable patties, which were neither liked nor disliked. Mean comparisons of sensory scores of sweet potato recipes and their controls were accomplished by using the Student t-test. Because of their nutritional adequacy and consumer acceptability, these products are being recommended to NASA's Advanced Life Support Program for inclusion in a vegetarian menu plan designed for lunar/Mars space missions.

Diet, Vegetarian↗
PubMed1998

Sweet potato in a vegetarian menu plan for NASA's Advanced Life Support Program.

Sweet potato has been selected as one of the crops for NASA's Advanced Life Support Program. Sweet potato primarily provides carbohydrate--an important energy source, beta-carotene, and ascorbic acid to a space diet. This study focuses on menus incorporating two sets of sweet potato recipes developed at Tuskegee University. One set includes recipes for 10 vegetarian products containing fom 6% to 20% sweet potato on a dry weight basis (pancakes, waffles, tortillas, bread, pie, pound cake, pasta, vegetable patties, doughnuts, and pretzels) that have been formulated, subjected to sensory evaluation, and determined to be acceptable. These recipes and the other set of recipes, not tested organoleptically, were substituted in a 10-day vegetarian menu plan developed by the American Institute of Biological Sciences (AIBS) Kennedy Space Center Biomass Processing Technical Panel. At least one recipe containing sweet potato was included in each meal. An analysis of the nutritional quality of this menu compared to the original AIBS menu found improved beta-carotene content (p<0.05). All other nutrients, except vitamin B6, and calories were equal and in some instances greater than those listed for NASA's Controlled Ecological Life Support Systems RDA. These results suggest that sweet potato products can be used successfully in menus developed for space with the added benefit of increased nutrient value and dietary variety.

Diet, Vegetarian↗
PubMed1997

Post-operative feeding strategies for infants with cleft lip.

UNLABELLED: Post-operative feeding techniques for infants following primary repair of cleft lip vary considerably. Recommendations range from immediate return to nipple feeding post-operatively to abstinence from nipple feeding for up to 6 weeks. Different surgeons prescribe different post-operative feeding protocols among and within centers. The purposes of this retrospective study (n = 42) were to: (1) identify the specific nonnipple feeding guidelines given to caregivers prior to surgery and the duration for those practices to be used in the post-operative period, (2) describe caregiver compliance, and (3) identify post-operative complications (e.g. dehiscence) related to type and duration of feeding strategies. Feeding guidelines included: nonnipple feeding for 6 weeks (n = 28, 67%), 3 weeks (n = 6, 14%), 2 weeks (n = 6, 14%), and unrestricted return to nipple (n = 2, 5%). Nearly all caregivers (n = 37, 88%) complied with recommendations. The others (n = 5, 12%) returned their infants to nipple feeding sooner than recommended (three in the nonnipple group for 6 weeks, and one each in the other two groups). No medical/surgical complications were related to feeding strategies. CONCLUSION: caregivers typically comply with post-operative feeding recommendations. However, the variability in those recommendations should be reduced with feeding made as easy as possible and not a jeopardy to wound healing.

Bottle Feeding↗