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Biomedical subjects

G A Bartholomew

Publications and source records attributed to G A Bartholomew.

9 recordsLinked to original sources
PubMed1988

Standard energy metabolism of a desert harvester ant, Pogonomyrmex rugosus: Effects of temperature, body mass, group size, and humidity.

Pogonomyrmex rugosus (Hymenoptera: Formicidae) is an important seed predator in the Mojave Desert of the southwestern United States. Its standard rate of O(2) consumption ( Vo(2)) varied significantly with temperature ( Vo(2) = 10((-1.588 + 0.0315T)), where Vo(2) is ml.g(-1).hr(-1) and T is body temperature in degrees C). The ratio of the Vo(2) values at 10 degrees C increments in body temperature, Q(10), also varied with temperature; methods of calculating Vo(2) from temperature with a shifting Q(10) are described. Vo(2) also varied with body mass ( Vo(2) = 0.0462M(0.669), where Vo(2) is ml.hr(-1) and M is body mass in g). Vo(2) was inversely related to relative humidity and was independent of group size. The rise in Vo(2) at low relative humidities was caused by increased activity and resulted in higher rates of net water loss. The primary metabolic adaptation to xeric conditions in P. rugosus appears to be a lower-than-predicted metabolic rate.

Journal Article↗
PubMed1986

The early ontogeny of ventilation and homeothermy in an altricial bird, Agapornis roseicollis (Psittaciformes).

The body temperature (Tb) of brooded Agapornis nestlings increased with age from 36.2 on the day of hatching to 38.9 degrees C on day 11.5, whereas the thermally neutral ambient temperature (Ta,n) decreased with age. The Tb of nestlings after a 20 min exposure to Ta approximately equal to 5 degrees C less than Ta,n increased from 31.9 on day 0.5 to 37 degrees C on day 11.5. At Ta,n both resting VO2 and mass-independent resting VO2 increased with age. Ventilation frequency (f) at Ta,n increased with age from 14.9 br/min on day 0.5 to 65.6 on day 11.5. This trend is the opposite of the allometric prediction based upon data from adult birds. At hatching, tidal volume (VT) was larger than predicted allometrically, whereas minute volume (VI) was smaller. After 20 min exposure to Ta 5 degrees C less than Ta,n, f, VT, and VI in nestlings 1 to 3 days old remained unchanged, but VO2 and oxygen extraction efficiency decreased. This mild cold-challenge caused a transient increase in VO2 of nestlings 5 to 8 days of age and 20 to 35% of adult mass. By the time the nestlings were 11.5 days old and had a mass 44% that of adults, their metabolic response to a mild cold-challenge was equal to that of an adult of the same mass. However, they were not capable of effective homeothermy over a wide range of Ta's.

Aging↗
PubMed1986

Oxygen consumption during hover-feeding in free-ranging Anna hummingbirds.

Rates of oxygen consumption during hover-feeding of wild, unrestrained, adult male Anna hummingbirds (Calypte anna) were measured with an artificial outdoor feeder converted into a respirometer mask. A computer sampled changes in O2 concentration in air drawn through the mask, automatically detecting the presence of a hummingbird from a drop in the O2 concentration, and photoelectrically timing the duration over which the feeder functioned as a mask. Birds coming to the feeder were weighed on a trapeze perch suspended from a force transducer. Feeding bouts consisted of sallies which carried the head in and out of the feeding mask about once a second. The volume of O2 consumed per feeding sally was linearly related to the length of the sally. The energy cost of hover-feeding in five hummingbirds, mean mass 4.6 g, was 41.5 +/- 6.3 ml O2 g-1 h-1.

Animals↗
PubMed1975

Allometry of post-flight cooling rates in moths: a comparison with vertebrate homeotherms.

1. The rates of post-flight cooling in 25 saturniid moths of 8 genera ranging in weight from 81 to 2650 mg were measured and compared with cooling rates in sphingids, birds and mammals. 2. The initial and terminal cooling rates of the saturniids did not differ significantly. 3. Large saturniids have relatively smaller thoraxes than small ones. 4. In saturniids the rate of post-flight cooling is inversely related both to thoracic volume and total weight. 5. Cooling rate is less dependent on thoracic volume in saturniids than in sphingids. 6. Weight-specific conductance calculated on the basis of total weight, shows that moths are not as well insulated as birds or mammals. However, when considered on the basis of thoracic weight, the weight-specific conductance of saturniids and sphingids closely approximates that predicted by the regression of weight-specific conductance on total body weight in birds and mammals. 7. Since the insulation of saturniids and sphingids is no more effective for animals of their size than is that of birds and mammals, their high body temperatures during activity appear to depend primarily on high levels of heat production.

Animals↗
PubMedDate not supplied

Oral candidiasis in patients with diabetes mellitus: a thorough analysis.

It has generally been assumed that oral candidiasis occurs with increased frequency in patients with diabetes mellitus. To evaluate this, we compared the frequency and severity of oral Candida colonization in 60 patients with insulin-dependent diabetes mellitus (IDDM) admitted to a low-intensity-care diabetes unit with those in 57 age- and sex-matched controls. Swabs taken from the tongue and buccal mucosa were examined by cytology rather than culture because of the discrimination provided by the former. Cytological smears were classified according to the presence and morphology of the Candida organisms. Overall, a significant difference in Candida species colonization was found between patients with diabetes (75.0%) and controls (35.1%) (P less than .005). In the diabetic group, no relationship was found to recent use of antibiotics, total or differential white blood cell count, serum glucose, presence of diabetic retinopathy, or glycosylated hemoglobin values. We conclude that in IDDM there is a predisposition to oral candidiasis and that this predisposition is independent of glucose control.

Adolescent↗