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Biomedical subjects

M A Harper

Publications and source records attributed to M A Harper.

27 records · Page 2Linked to original sources
PubMed1987

Human fetal breathing response to intravenous glucose is directly related to gestational age.

This prospective longitudinal study examined human fetal breathing activity over the second half of pregnancy both in the fasting state and after intravenous glucose administration. There was a linear relationship between gestational age and percent time spent breathing after glucose between 19 and 38 weeks' gestation. However, no such correlation could be demonstrated between gestational age and fetal breathing activity in the fasting state.

Embryonic and Fetal Development↗
PubMed1983

Comparison of tubal surgery with the CO2 laser and the unipolar microelectrode.

The uterine horns of 40 New Zealand White female rabbits were resected and anastomosed to compare microsurgical anastomosis of the horns excised with microscissors, with a laser, and with a microelectrode. The rabbits were divided into four groups. In the first group of ten rabbits, 3 cm of tissue was resected by microscissors from each uterine horn; the cut ends were then anastomosed in one layer with 8-0 Vicryl sutures using the operating microscope. In the second group of ten rabbits, 3 cm of tissue was resected by laser from each uterine horn; the cut ends were then anastomosed in one layer with 8-0 Vicryl. In the third group of ten rabbits, 3 cm of tissue was resected by laser from each uterine horn; the cut ends were then anastomosed by "welding" the tissues with the laser. In the fourth group of ten rabbits, 3 cm of tissue was resected by a microelectrode; the cut ends were then anastomosed in one layer with 8-0 Vicryl sutures using loupe magnification. All the rabbits in the first and fourth groups became pregnant, only four became pregnant in the second group, and none became pregnant in the third group. It is concluded that the CO2 laser beam as used in this study has no place in tubal resection and reconstruction.

Animals↗
PubMed1977

Cerebral circulatory and metabolic effects of 5-hydroxytryptamine in anesthetized baboons.

1. The cerebral circulatory effects of the intracarotid administration of 5-hydroxytryptamine were examined in anaesthetized baboons. Cerebral blood flow was measured by the intracarotid 133Xe technique, cerebral O2 consumption and glucose uptake were measured as indices of brain metabolism and electrocortical activity was continuously monitored. 2. Despite a marked reduction in the calibre of the internal carotid artery (assessed angiographically), the intracarotid infusion of 5-hydroxytryptamine 0-1 microgram/kg. min did not effect any significant changes in cerebral blood flow, O2 consumption or glucose uptake. 3. Following transient osmotic disruption of the blood-brain barrier with the intracarotid infusion of hypertonic urea, the same dose of 5-hydroxytryptamine effected a marked reduction in cerebral blood flow from 51 +/- 2 to 36 +/- 2 ml./100 g. min (mean +/- S.E.; P less than 0-01). Both indices of cerebral metabolism were reduced significantly and the e.e.g. showed a more pronounced suppression-burst pattern. 4. We postulate that the cerebral circulatory responses to 5-hydroxytryptamine are dependent upon the integrity of the blood-brain barrier and the predominant effect of the intravascular administration of 5-hydroxytryptamine is on cortical activity or metabolism, rather than on cerebrovascular smooth muscle.

Animals↗
PubMedDate not supplied

In search of effective education in burn and fire prevention.

Children younger than 14 years continue to be a high-risk group for burn-related and fire-related injuries. Burn and fire educators must find a way to reach these children that captures their imaginations. There may be no better way than games. Two burn and fire prevention games were developed. The games were distributed to 38 school districts encompassing a total of 164 elementary schools and reaching more than 1,035 youngsters in grades 1 through 4 in a two-county community. Before playing each game, the participants completed a multichoice pretest. A similar posttest was administered after gaming to determine mastery and retention of knowledge. In addition, classroom instructors were given an evaluation form to assess content, quality, and effectiveness. Pretest and posttest results indicated students gained and retained significant knowledge. Instructor evaluation recognized these games as entertaining and exciting, precipitating additional questions leading to further classroom discussion and learning.

Adolescent↗
PubMedDate not supplied

A prospective study of insulin sensitivity and glucose metabolism in women using a continuous subdermal levonorgestrel implant system.

OBJECTIVE: Decreased insulin sensitivity and deterioration in oral glucose tolerance curves have been reported with oral contraceptive use, particularly with those containing levonorgestrel. However, the subdermal levonorgestrel systems release a lower dosage of steroid and avoid the first pass through the liver that occurs with oral administration. We hypothesized, therefore, that continuous subdermal levonorgestrel has no significant effect on insulin sensitivity and other indices of glucose metabolism. METHODS: Nine women desiring a subdermal hormonal contraceptive system were recruited for this longitudinal prospective study. Each subject underwent a 3-hour frequently sampled intravenous glucose tolerance test immediately before insertion and after 6 months of continuous use. Insulin sensitivity and glucose effectiveness were determined using a mathematical minimal modeling approach. Glucose clearance and fasting and peak levels of glucose and insulin were examined as well. The matched-pair data were analyzed using paired t tests. RESULTS: There was no significant change in insulin sensitivity, glucose effectiveness, glucose clearance, or fasting or peak insulin levels. Fasting glucose levels remained within a normal range. CONCLUSIONS: Subdermal levonorgestrel appears to have no significant effect on tissue insulin sensitivity or glucose metabolism after 6 months of continuous use.

Adolescent↗