Comparative sequence analysis of mammalian factor IX promoters.
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Animals↗
Biomedical subjects
G Kent
Publications and source records attributed to G Kent.
Reduced tracheal growth after reconstruction with pericardium.
Four groups of piglets were used to test the use of pericardium and periosteum as free grafts in the repair of full thickness cervical tracheal defects. Pericardium provided an airtight, rapidly healing graft, but did not give sufficient structural rigidity to prevent narrowing and growth failure at the graft site. Composite grafts of pericardium and periosteum were also unsatisfactory, in that the periosteum failed to produce enough bone to prevent collapse of the graft. Since previous studies have shown that periosteal grafts result in good bone formation when applied alone or as an extramucosal support, it is concluded that the osteogenic potential is dependent on the available blood supply and speed of revascularization. It appears that the presence of pericardium in the composite grafts may have inhibited this property.
Animals↗
A longitudinal study of the intrusiveness of cognitions in test anxiety.
Medical students who had to undergo an important set of examinations were asked to fill out two questionnaires, the first early in the term, the second 1 or 2 wk before the exams. Students whose anxiety increased substantially between the two questionnaire administrations reported that their thoughts had become more intrusive on a number of parameters including distress, frequency and dismissability. Subjects whose anxiety increased only moderately or not at all reported correspondingly smaller changes in intrusiveness. There was considerable stability in reported cognitions over time, but changes in anxiety were related to changes in reports of thought content. The perceived probability of negative outcomes did not vary over time. These results indicate that changes in anxiety levels over time are related to several parameters of intrusiveness as well as thought content.
Adult↗
Effect of hypothermia on the pharmacokinetics of ethanol in piglets.
The effect of hypothermia (29 C) on the pharmacokinetics of ethanol was studied in eight piglets serving as their own normothermic controls. Ten milliliters of 12% ethanol per kilogram were infused over 30 minutes, and serum ethanol concentrations were measured for seven hours. Ethanol concentration data were fitted to one-compartment open model assuming Michaelis Menten elimination kinetics. During hypothermia, ethanol concentrations were consistently higher than during normothermia. This observation could be explained by both a significantly smaller distribution volume of ethanol during hypothermia (0.71 +/- 0.03 L/kg at 29 C and 0.84 +/- 0.05 L/kg at 37 C, P less than .02) and a significantly slower maximum velocity of metabolism of ethanol (Vm) during hypothermia (1.12 +/- 0.11 mg/kg.min vs. 1.83 +/- 0.21 mg/kg.min, P less than .01). Our study indicates that during hypothermia, ethanol stays significantly longer in the circulation in piglets. Potentially, this may contribute to a more profound effect from the ethanol.
Animals↗
Effect of esophageal ligation on the growth of fetal rabbits.
Controversy continues regarding the nutritional value to the fetus of swallowed amniotic fluid. To clarify this issue further, esophageal ligations were performed to prevent deglutition in utero in 63 fetal rabbits during the final trimester of pregnancy. Compared with sham-operated littermate controls, the fetuses that were ligated for periods of 4, 5, or 6 days showed significant reductions in weight of 6.1, 18.9, and 9.2%, respectively. These results compare well with the magnitude of weight reduction seen clinically in patients with esophageal atresia. Significant but less consistent reductions were also noted in crown-rump length and biparietal diameter. No significant differences were seen in either body composition or gastrointestinal tract histology. These results indicate that swallowed amniotic fluid does play a role in fetal nutrition and may be particularly important in the later stages of gestation when placental function is limited.
Amniotic Fluid↗
Reactivity of the measurement of cognitions associated with dental anxiety.
There are several reasons to suppose that sampling the contents of consciousness can affect patients' mood. In an attempt to explore the effect on state anxiety of inquiring about cognitions associated with dental anxiety, 90 patients waiting to see a dentist were asked about the content of their ideation. One group was asked whether they had ever experienced any of a list of negative thoughts, a second group any listed positive thoughts and a third group any listed neutral thoughts. As measured by the PARQ, the emotional and cognitive components of state anxiety were higher in the positive and negative conditions relative to the neutral condition, perhaps because patients' attempts to distract themselves were overridden by the investigator's inquiries.
Adaptation, Psychological↗
A new intratracheal stent for tracheobronchial reconstruction: experimental and clinical studies.
An intraluminal tracheal stent (ITS) was used experimentally in rabbits and piglets, as well as clinically in infants with tracheal stenosis, to facilitate airway reconstruction. The ITSs were constructed of stainless-steel springs covered with silicone rubber. They were implanted in seven piglets (6 to 8 kg), five rabbits (3 to 5 kg) and three infants. No animals developed severe respiratory distress and all appeared to tolerate the ITS. Postmortem examinations 1 to 8 weeks after surgery showed (1) loss of stent fixation (one pig), (2) increased tracheal secretions, (3) pneumonia (one pig, two rabbits), and (4) focal squamous metaplasia of tracheal mucosa. Stents used to treat three infants (2 to 5 months of age) with complex tracheobronchial stenosis were placed at the time of periosteal tracheoplasty in two. Recurrent stenosis necessitated a second tracheoplasty and stenting in one, and a long tracheostomy tube and balloon dilatations in the other. The third child had endoscopic stent insertion to alleviate severe airway collapse after esophageal tracheoplasty. The child died from progressive respiratory failure after stent dislodgment. Although the stents were well tolerated in animals and they enhanced critical ventilation of all pulmonary lobes in infants after tracheal reconstruction, certain modifications such as alternative methods of fixation, accommodation for tracheal growth, and reduction in tissue reactivity are necessary before further use of the ITS can be advocated.
Animals↗
A new technique of experimental heterotopic cardiac transplantation.
Heterotopic cardiac transplantation is a useful method for studying allograft rejection. In this study a new technique of cardiac transplantation was carried out, which involved retroperitoneal anastomoses of the donor ascending aorta and main pulmonary artery with the recipient abdominal aorta and inferior vena cava respectively. The procedure was simple and effective and was accomplished with minimal operative mortality and postoperative morbidity. The method allows better access to the allograft for repeated open myocardial biopsies, obviating the limitations of transvenous fluoroscopically directed endomyocardial biopsy. This technique of retroperitoneal heterotopic cardiac transplantation has important advantages compared with similar procedures performed in the neck, abdomen, or thorax.
Animals↗
Atresia of the esophagus. New trends in the management of high-risk neonates.
Once the reconstruction of esophageal atresia in infancy was reported, immediate repair became standard practice. High-risk infants carry an operative mortality of 30% to 80%. Staged surgical procedures were introduced to improve survival. "Delayed" reconstruction of esophageal atresia in selected cases has been reported to improve survival and eliminate staged surgical procedures. Between 1982 and 1986, 21 newborns were diagnosed as having esophageal atresia. Eight infants (32%) underwent "immediate" repair. In 13 infants repair was "delayed" for seven to 252 days. Four neonates with "pure" esophageal atresia underwent primary anastomosis, one was awaiting surgery, and another died in the postnatal period. As more high-risk infants survive the perinatal period, surgical reconstruction must be planned to maximize operative survival. The goal of delayed management of esophageal atresia is to restore intrinsic esophageal continuity.
Abnormalities, Multiple↗
The influence of hypothermia on the disposition of fentanyl--human and animal studies.
The effect of hypothermia on the disposition of fentanyl was evaluated in 18 children undergoing corrective cardiac surgery. They received a bolus of fentanyl followed by a continuous infusion which was stopped when cardiopulmonary bypass was established and profound hypothermia was achieved (18 degrees C-25 degrees C). Fentanyl plasma concentration remained essentially unchanged during hypothermia (6.45 ng/ml 5 min into hypothermia and 5.26 ng/ml 100-140 min later; p greater than 0.1). In subsequent experiments, the effect of hypothermia on the pharmacokinetics of fentanyl was studied in 4 piglets serving as their own controls. Both distribution volume (Vz) and total body clearance (CL) were significantly smaller during hypothermia. Our studies indicate that being a drug with a large distribution volume and a high hepatic extraction ratio, both CL and Vz are significantly reduced by hypothermia-induced hypoperfusion. In addition, TBC is influenced by the temperature-dependent hepatic metabolism of fentanyl.
Adolescent↗
Self-efficacy and the control of anxious cognitions.
This study was designed to explore the possibility that Bandura's notion of self-efficacy can be applied to control over cognitions as well as behavior. Subjects were asked to complete questionnaires designed to measure their dental anxiety, the number of their negative self-statements about a dental appointment and their perceived ability to control these thoughts. Subjects with low anxiety claimed to experience fewer negative thoughts than those with moderate or high anxiety, and also to have more control over these thoughts. Subjects believed that the extent of their control would decline as the appointment approached in time, but least for the low anxiety group and most for the high anxiety group. Finally, differences in self-efficacy scores between anxiety groups were maintained when the number of negative thoughts was controlled for, but differences in negative thinking between anxiety levels were not maintained when self-efficacy was controlled for. These results suggest that anxiety is more closely related to thinking processes than content.
Adult↗
Self-efficacious control over reported physiological, cognitive and behavioural symptoms of dental anxiety.
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Adolescent↗
Tracheomalacia: an experimental animal model for a new surgical approach.
Tracheomalacia was created by removing the posterior 50% of the circumference of eight cartilage rings (5-6 cm in length) from the intrathoracic trachea in each of 12 piglets while leaving the mucosa intact. In 6 animals an autologous, free tibial periosteal graft was applied over the defect (graft group). The remaining 6 piglets served as the control group. In all animals, a silastic stent was left in the trachea for 2 weeks to prevent immediate tracheal collapse. The presence of tracheomalacia was assessed 6-8 weeks after surgery. At bronchoscopy total tracheal collapse during coughing occurred only in the controls. As the animals went from quiet breathing to coughing, mean intrathoracic pressure increased from 5 to 80 cm H2O in both groups, and average sagittal tracheal diameter decreased by 10% in the graft group and 71% in the controls. During coughing, mean resistance to airflow across the defect increased by 0.005 +/- 0.002 cm H2O/liter/min in the graft group, by 0.083 +/- 0.96 cm H2O/liter/min in the controls (P less than 0.005), and by 0.027 cm H2O/liter/min at the same tracheal level in two normal pigs. At sacrifice 12 weeks postoperatively, bone and collagenized fibrous tissue had been produced by all grafts, without evidence of stricture. This study shows that experimentally induced tracheomalacia can be treated successfully by the application of an autologous periosteal tibial graft, which becomes incorporated into the weakened tracheal wall.
Airway Resistance↗
Behavioural sciences teaching in UK dental schools.
A survey was conducted of the dental schools in the UK, inquiring about the teaching of psychology, sociology, epidemiology and psychiatry to dental undergraduates. Epidemiology was the most frequently taught and assessed subject, followed by psychology and sociology. Overall, the results indicate an increased concern with and attention to behavioural sciences teaching.
Behavioral Sciences↗
Fish and nutrition in the Pacific Islands.
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Adult↗
The typicality of therapeutic 'surprises'.
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Adolescent↗
Effect of pre-appointment inquiries on dental patients' post-appointment ratings of pain.
In order to test the possibility that an investigator's inquiries about dental patients' anxiety and expectations of pain will enhance their subsequent discomfort, two groups of 51 patients were asked after their appointment about the amount of pain they had experienced, but only one group was interviewed beforehand. No difference between these groups was found.
Adolescent↗
Partial recovery of neutrophil functions during prolonged hypothermia in pigs.
The changes in circulation and migration of mature and immature neutrophils during 12 h of hypothermia have been studied using an experimental pig model. At 29 degrees C the number of circulating neutrophils fell from 5 +/- 1.1 at 37 degrees C to 3.5 +/- 0.6 X 10(9)/l and then remained unchanged while hypothermia was maintained. The number of circulating immature neutrophils did not fall during hypothermia. During hypothermia, hydrocortisone failed to stimulate the release of mature and immature neutrophils from the bone marrow. In contrast, endotoxin caused a profound neutropenia followed by a gradual increase in the number of circulating mature neutrophils, which by 6 h, was similar to the number circulating before endotoxin administration. At 29 degrees C the number of circulating immature neutrophils also fell following endotoxin but then increased over the number circulating before endotoxin administration by approximately 10-fold. Compared with neutrophil migration at 37 degrees C, very few mature or immature neutrophils migrated to an inflammatory site during the 12 h of hypothermia (29 degrees C). Unlike hypothermia in vitro, where neutrophil function may improve with time in vivo, neutrophil function remains compromised.
Animals↗