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D Starr

Publications and source records attributed to D Starr.

9 recordsLinked to original sources
PubMed2003

Locating broken dental needles.

Broken dental needles are a rare event. They are difficult to find and remove. We report two cases in which broken needles were located using a simple stereotactic method with the aid of an image intensifier.

Anesthesia, Dental↗
PubMed1998

Susceptibility and outcome in oral cancer: preliminary data showing an association with polymorphism in cytochrome P450 CYP2D6.

Members of the cytochrome P450 and glutathione S-transferase supergene families are candidates for susceptibility and outcome in oral squamous cell cancer. We determined GSTM1, GSTM3, GSTT1, CYP1A1 and CYP2D6 genotypes in 100 Caucasian cases and 467 control individuals. The frequency of homozygosity for mutant CYP2D6 alleles was higher in the cases (P = 0.001, OR = 3.2, 95% CI = 1.6-6.5) than control individuals. In the cases, the frequency of homozygosity for mutant alleles was greater and that of homozygosity for wild-type CYP2D6 alleles was lower in those diagnosed at > or = 65 years (P = 0.009) than in those diagnosed at < or = 64 years. The older cases included relatively more women and patients who did not consume tobacco or alcohol. The association of CYP2D6 with outcome was assessed using the Cox's proportional hazards model. The time to first cervical node metastasis was shorter in heterozygotes and homozygotes for mutant CYP2D6 alleles compared with homozygotes for wild-type alleles after correction for age at diagnosis, gender, alcohol and tobacco consumption and tumour differentiation (P = 0.04, hazard ratio 3.6, 95% CI 1.1-12.5). The mechanism for the association of CYP2D6 alleles with susceptibility and outcome is unclear though the data are compatible with the view that homozygosity for mutant alleles confers impaired detoxication of an unknown carcinogen. No associations between GSTM1, GSTM3, GSTT1 or CYP1A1 genotypes and susceptibility or, time to node metastases were identified. We previously showed that CYP2D6 genotypes were not associated with susceptibility to squamous cell cancer in the pharynx or larynx. Therefore, the data presented suggest that susceptibility to squamous cell cancer in the various parts of the upper aerodigestive tract is associated with different genes and allelic variants.

Adult↗
PubMed1988

Carnitine palmitoyltransferase: effects of diabetes, fasting, and pH on the reaction that generates acyl CoA.

Although carnitine palmitoyltransferase (CPT) has received considerable attention, particularly its regulation by malonyl CoA, most studies have monitored the forward reaction, ie, the formation of acylcarnitine. We examined the opposite or reverse reaction, in which palmitoyl CoA is generated, in osmotically-disrupted rat hepatic mitochondria. Specifically, the effects of pH, fasting, and untreated recent-onset diabetes were investigated. As with the forward (f) reaction, the CPT reverse (r) velocity v pH curve was somewhat parabolic with a pH maximum at approximately 7.2 (except the CPT that was from the diabetic rats). However, as the pH rose, the CPT reverse and forward curves diverged due to a precipitous decline in the forward reaction. This discordance in rates in the alkaline range was apparent in all three groups of CPT but was most prominent in the diabetic preparation (for example, as the pH increased from 7.3 to 8.8, the respective declines in the f and r velocities were 74% and 2%). In addition, under our assay conditions the CPTr from diabetic rats not only had a higher velocity (55.4 +/- 1.4 nmol/min/mg protein) than that from the fed (32.1 +/- 3.1) or fasted (43.1 +/- 3.4) animals, but also the Vmax was found to be twofold greater, even though there was no difference in the Km for palmitoylcarnitine. In summary, diabetes affects the kinetics of the reverse reaction and, regardless of the animal's premortem condition, but more so in the diabetes, this reaction is less attenuated than the forward one as the pH rises.

Acyl Coenzyme A↗
PubMed1968

The effects of chloralose-urethane and sodium pentobarbitone anaesthesia on the local and autonomic components of the circulatory response to arterial hypoxia.

1. The circulatory and respiratory responses to severe arterial hypoxia were studied in normal rabbits, ;de-efferented' rabbits without functioning autonomic effectors, and atropinized animals before anaesthesia and during chloralose-urethane and sodium pentobarbitone anaesthesia. Net systemic autonomic activity and autonomic activity to the heart was assessed from a comparison of the responses of the various preparations.2. In the normal spontaneously breathing animal each anaesthetic had a similar mode of action, and modified qualitatively the circulatory response present before anaesthesia. In the ;de-efferented' animal the circulatory response was determined by the local effects of hypoxia, and was altered only quantitatively during anaesthesia.3. In the normal unanaesthetized animal the reflex changes in autonomic activity during hypoxia consisted of a large increase in vagal efferent activity, a decrease in cardiac sympatho-adrenal activity, and an increase in total sympatho-adrenal constrictor activity.4 In hypoxia during anaesthesia the vagal efferent activity no longer increased, but the change in sympatho-adrenal activity to heart and systemic circulation was the same as before anaesthesia in the spontaneously breathing animal. During anaesthesia with controlled ventilation systemic sympatho-adrenal activity increased further, and bradycardia again developed. The bradycardia was now due exclusively to reduction in cardiac sympathetic activity and not to an increase in vagal efferent activity.

Animals↗