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Biomedical subjects

T Wheatley

Publications and source records attributed to T Wheatley.

At least 19 recordsLinked to original sources
PubMed2001

Identification of mtDNA mutation in a pedigree with gestational diabetes, deafness, Wolff-Parkinson-White syndrome and placenta accreta.

Mitochondrial DNA (mtDNA) defects are associated with a number of human disorders. Although many occur sporadically, maternal transmission is the hallmark of diseases due to mtDNA point mutations. The same mutation may manifest strikingly different phenotypes; for example, the A to G substitution at np 3243 was first reported in patients with mitochondrial encephalomyopathy, lactic acidosis and stroke-like episodes (the MELAS syndrome), but is also found in patients with diabetes and deafness. Here we present a case of gestational diabetes, deafness, premature greying, placenta accreta and Wolff-Parkinson-White (WPW) syndrome associated with a mtDNA mutation. Although this is the first report of such an association, study of 27 other patients with WPW syndrome failed to confirm that this mtDNA mutation is a common cause of such pre-excitation disorders.

Adult↗
PubMed2000

Focalism: a source of durability bias in affective forecasting.

The durability bias, the tendency to overpredict the duration of affective reactions to future events, may be due in part to focalism, whereby people focus too much on the event in question and not enough on the consequences of other future events. If so, asking people to think about other future activities should reduce the durability bias. In Studies 1-3, college football fans were less likely to overpredict how long the outcome of a football game would influence their happiness if they first thought about how much time they would spend on other future activities. Studies 4 and 5 ruled out alternative explanations and found evidence for a distraction interpretation, that people who think about future events moderate their forecasts because they believe that these events will reduce thinking about the focal event. The authors discuss the implications of focalism for other literatures, such as the planning fallacy.

Affect↗
PubMed1999

Apparent mental causation. Sources of the experience of will.

The experience of willing an act arises from interpreting one's thought as the cause of the act. Conscious will is thus experienced as a function of the priority, consistency, and exclusivity of the thought about the action. The thought must occur before the action, be consistent with the action, and not be accompanied by other causes. An experiment illustrating the role of priority found that people can arrive at the mistaken belief that they have intentionally caused an action that in fact they were forced to perform when they are simply led to think about the action just before its occurrence.

Causality↗
PubMed1997

Recent advances in prophylaxis against deep vein thrombosis.

The major development in DVT prophylaxis in recent years has been the introduction of low molecular weight heparins. Their main improvement compared with unfractionated heparin is in the convenience of a once daily dosage, but they have not yet convincingly been shown to be more effective or safer. A-V impulse boots may have an impact on knee and hip surgery but still face problems with patient acceptability. Probably the best way to ensure that more DVT are prevented is by clinicians maintaining a high level of awareness of the risk, and developing, and adhering to, local guidelines.

Anticoagulants↗
PubMed1996

Dilution potential: a new perspective.

The objective of this work was to develop a method to assess the dilution capacity of direct compression excipients based on a technique previously proposed by Minchom and Armstrong (MA). The technique involves the addition of increasing quantities of a poorly compactible (compressible) material to the excipient and measuring the resultant decrease in the AUC of the tensile strength versus compaction force profiles. The AUC of each mixture is divided by the AUC of the "0% mixture" to obtain MA's "work potential," called "area ratios" in the present study. The applicability of this approach was tested using three excipients differing in their deformation mechanisms: microcrystalline cellulose (Avicel PH 101, 102, 200, 301, 302) representing a plastic material; dibasic calcium phosphate (Cal-Star) representing a brittle material, and anhydrous lactose, which exhibits both brittle and plastic properties. Ascorbic acid or acetaminophen was the poorly compactible challenge material. In the first study, the MA method was found to apply only to Avicel PH 101, since the area ratios for mixtures containing different compositions of acetaminophen with either Cal-Star or anhydrous lactose remain constant until a certain percentage of drug is exceeded, after which a decline starts to be observed. Further work carried out on mixtures of different grades of Avicel with ascorbic acid revealed that MA's approach reflects only the ability of the excipient to handle internal stress induced by the drug and does not take into account the intrinsic ability of the drug-free excipient to form strong compacts. A new index was thus proposed, called the dilution capacity index (DCI), which weights the MA index by the AUC of the drug-free excipient. The results suggest that DCI can be used to compare different grades of microcrystalline cellulose and provide in-house quality control for microcrystalline cellulose suppliers.

Acetaminophen↗
PubMed1995

Nonsteroidal antiinflammatory drug-induced colonic stricture. An unusual cause of large bowel obstruction and perforation.

Nonsteroidal antiinflammatory drugs (NSAIDs) are widely prescribed drugs that can result in gastroduodenal ulceration. Adverse effects upon the small and large intestine are now more often recognized. Small intestinal obstruction secondary to both mucosal diaphragms and broad-based stenoses is reported, but colonic strictures appear to be less common. A case of NSAID-induced colonic stricture leading to large bowel obstruction and secondary cecal perforation (previously unreported) is presented. Twelve additional cases of NSAID-induced colonic stricture are reviewed from the literature and its possible pathogenesis is discussed.

Acetaminophen↗
PubMed1995

White-centered retinal hemorrhages as an early sign of preeclampsia.

PURPOSE/METHOD: We examined a pregnant patient who had symptomatic white-centered retinal hemorrhages. Severe preeclampsia rapidly developed despite the patient not having hypertension, proteinuria, or edema at initial examination. RESULTS/CONCLUSIONS: Retinal hemorrhages gradually resolved without treatment and visual acuity returned to 20/20 six months after emergency delivery of a healthy infant. Retinal or choroidal vascular abnormalities in pregnant patients may be caused by early preeclampsia and immediate obstetric referral is indicated.

Adult↗
PubMed1991

Thirst and salt appetite in horses treated with furosemide.

When a preliminary experiment in sodium-replete ponies revealed an increase, but not a significant increase, in salt consumption after furosemide treatment, the experiment was repeated using sodium-deficient horses in which aldosterone levels might be expected to be elevated to test the hypothesis that a background of aldosterone is necessary for salt appetite. Ten Standardbred mares were injected intravenously with furosemide or an equivalent volume of 0.9% sodium chloride as a control to test the effect of furosemide on their salt appetite and blood constituents. Sodium intake and sodium loss in urine, as well as water intake and urine output, were measured and compared to determine accuracy of compensation for natriuresis and diuresis. Plasma protein and packed cell volume showed significant increases in response to furosemide treatment (F = 29.31, P less than 0.001 and F = 11.20, P less than 0.001, respectively). There were no significant changes in plasma sodium concentration or osmolality in response to the treatment (P greater than 0.05). The furosemide-treated horses consumed 126 +/- 14.8 g salt, significantly more than when they were given the control injection (94.5 +/- 9.8 g; t = 2.22, P = 0.05). In response to furosemide, horses lost 962 +/- 79.7 and consumed 2,170 +/- 5 meq sodium; however, compared with control, they lost 955 meq more sodium and ingested only 570 meq more sodium, so they were undercompensating for natriuresis. The furosemide-treated horses drank 9.6 +/- 0.8 kg of water, significantly more than when they received the control injection (6.4 +/- 0.8 kg; t = 6.9, P less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1989

Abnormalities of thyrotrophin (TSH) evening rise and pulsatile release in haemodialysis patients: evidence for hypothalamic-pituitary changes in chronic renal failure.

Using a sensitive enzyme amplified immunoassay for TSH, the evening rise and pulsatile release of TSH were studied in 10 men with chronic renal failure treated by haemodialysis. Compared to euthyroid male controls the evening rise of TSH was attenuated (median 0.066 vs 0.195 mU/l/h, P less than 0.01) and the rate of rise correlated with the TSH response to TRH (r = 0.93, P less than 0.001). All subjects showed TSH pulsatility in at least one method of data analysis but the less sensitive incremental method showed no significant difference in pulse frequency and amplitude between the two groups. However, with time series analysis, periodicity was shorter (median 45 vs 95 min, P = 0.013) and pulse amplitude smaller (median 0.06 vs 0.175 mU/l, P = 0.017) in renal patients. Pulse amplitude, but not periodicity, correlated with the TSH response to TRH (r = 0.68, P less than 0.05). In addition, serum total thyroxine, free thyroxine and free triiodothyronine concentrations were reduced, while serum prolactin and 17 beta-oestradiol concentrations were raised. These changes in TSH evening surge and pulsatile release may contribute to the reduction in thyroidal hormone concentrations seen in renal failure and emphasize the value of sensitive methods of hormone and pulse data analysis.

Adult↗
PubMed1989

Studies of the entero-insular axis following pancreas transplantation in man: neural or hormonal control?

To study the role of hormonal and neural factors in the control of the entero-insular axis the insulin, C-peptide, and glucose-dependent insulinotropic peptide (GIP) responses to oral and intravenous glucose were investigated in 5 patients who had received a combined kidney and paratopic pancreas transplant, with physiological portal venous drainage. The incremental areas under the insulin and C-peptide responses to oral glucose were significantly greater than the responses to intravenous glucose (insulin: patients 7983 +/- 1937 (+/- SE) vs 3513 +/- 2188 mU l-1 min, p less than 0.002, control subjects 5505 +/- 1035 vs 1066 +/- 484 mU l-1 min, p less than 0.004; C peptide: patients 440 +/- 80 vs 144 +/- 61 nmol l-1 min, p less than 0.01, control subjects 200 +/- 38 vs 63 +/- 16 nmol l-1 min, P less than 0.01). The incretin effects for insulin (patients 4.4 +/- 1.4, control subjects 7.7 +/- 1.8) and C-peptide (patients 4.4 +/- 0.9, control subjects 3.7 +/- 0.9) and the GIP responses to oral and intravenous glucose were not significantly different between transplant patients and control subjects. As the incretin effect was preserved, despite a denervated pancreas, hormonal rather than neural factors may be more important in mediating increased insulin secretion after oral carbohydrate. The normal GIP response is compatible with its proposed role as an insulinotropic hormone.

Adult↗