Biomedical subjects
B Cox
Publications and source records attributed to B Cox.
Severe anomalies associated with ring chromosome 7.
A newborn infant with the polyasplenia sequence, intrauterine growth retardation, cutaneous nevi, and minor anomalies was found to have mosaicism for ring chromosome 7. This patient's anomalies are markedly different from those of previous patients reported with this cytogenetic anomaly.
Transcript mapping reveals different expression strategies for the bicistronic RNAs of the geminivirus wheat dwarf virus.
We have characterised the major transcripts of the Czech isolate of wheat dwarf virus (WDV-CJI) which show that WDV uses two different mechanisms for expressing overlapping open reading frames (ORFs). Mapping of the virion sense RNAs identified a single polyadenylated transcript of 1.1kb spanning the overlapping ORFs V1 and V2 which encode cell-cell spread functions and the coat protein respectively. This finding distinguishes WDV from other monocot-infecting geminiviruses studied so far which were shown to encode two 3' co-terminal transcripts capable of expressing either the V1 or V2 ORF. A survey of codon usage at the junction between the V1 and V2 ORF has led us to propose that translational frame shifting analogous to that in the yeast Ty element may occur. Analysis of polymerase chain reaction (PCR) amplified complementary sense cDNA clones has revealed the presence of mature spliced and unspliced RNAs which could encode products of an intron mediated C1:C2 ORF fusion or the C1 ORF product alone. Mapping of the 5' and 3' extremities of the major WDV encoded transcripts has allowed us to identify putative transcription regulatory sequences and the presence of multiple overlapping transcripts may suggest temporal regulation of transcription.
The effect on the stratum-specific odds ratios of nondifferential misclassification of a dichotomous covariate.
Precise measurement of confounding or effect modifying variables is seldom possible. Nondifferential misclassification of such a variable can introduce bias in the odds ratios within the strata of the confounding variable. For two strata, the effect on the odds ratios is dependent on separate measures of the degree of nondifferential misclassification of the confounding variable. The authors investigate the bias in the stratum-specific odds ratios from nondifferential misclassification of a confounder in a case-control study, and show how estimates of the true stratum-specific odds ratios can be derived. For one stratum, the degree of bias introduced in the odds ratio is dependent only on the sensitivity of the measure of the confounding variable while only the specificity of this measure determines the bias introduced in the other stratum-specific odds ratio. The results are applied to a case-control study of fenoterol prescription and asthma death.
Suicide in New Zealand 1957-1986: the influence of age, period and birth-cohort.
New Zealand suicide rates from 1957 to 1986 were analysed for age, period and cohort effects. Cumulative suicide rates were relatively stable but more complex patterns were revealed by detailed analysis. There was a steadily increasing rate in young men and a recent increase in elderly men. Reduced mortality rates in equivalent categories of accidental and "undetermined" deaths could have accounted for only a proportion of these increases. A cohort effect was noted in men, with increasing risks of suicide in the young for successive birth-cohorts born from 1947 onwards. In women a period effect was likely, with increasing rates for all age-groups between 1957-61 and 1962-66, followed by a decline recently among all except the youngest age-groups. These trends in women may have been largely due to changes in barbiturate prescribing. In both sexes poisoning declined as a method of suicide, while hanging and carbon monoxide poisoning increased. Firearm suicides also increased in men. The implications of these results for prevention are considered.
Dosing schedule for recombinant hepatitis B vaccine.
Explore the source record for details and available documents.
A feasibility study of organised cervical screening in southern New Zealand.
The 1985 electoral roll was used as a register to invite 1013 women to participate in a screening program. Appointment times and a choice of venues for having a smear were not provided. Overall, 26 per cent of the women sent invitations registered with the program. After adjustment for the prevalence of hysterectomy, the proportion who registered with the program was about 32 per cent. The low level of registration and difficulties experienced in tracing registrants and nonregistrants over time using the electoral roll resulted in the cessation of the program after 3 years. An assessment of the original invitation was made using a small case-control study, and associations between the screening history stated at interview and screening over the duration of the program were examined in nonregistrants.
Pharmacological studies in vivo with ICI 169,369, a chemically novel 5-HT2/5-HT1C receptor antagonist.
ICI 169,369 (2-(2-dimethylaminoethylthio-3-phenylquinoline hydrochloride) has been tested in vivo for its potency and selectivity as an antagonist at 5-HT2 and 5-HT1C receptors. It caused a 50% inhibition of 5-HTP-induced head twitches in mice and fenfluramine-induced hyperthermia in the rat at approximately 1 mg/kg following parenteral administration. Results showed that ICI 169,369 had good oral bioavailability, since in the fenfluramine test the oral and s.c. ID50 values were similar. ICI 169,369 was a selective antagonist of 5-HT-induced bronchoconstriction in the guinea-pig and 5-HT-induced pressor effects in the anaesthetised dog. In a series of other tests in vivo the compound was shown to be devoid of significant activity at alpha 1- and alpha 2-adrenoceptors, dopamine (D2), muscarinic (M1) and histamine (H1) receptors at 30-100 times its ID50 values used in the 5-HT tests. Thus, ICI 169,369 is a selective, orally active 5-HT2/5-HT1C antagonist that should prove useful in the analysis of the role of 5-HT in physiological and pathological states.
Structural instability of human tandemly repeated DNA sequences cloned in yeast artificial chromosome vectors.
The suitability of yeast artificial chromosome vectors (YACs) for cloning human Y chromosome tandemly repeated DNA sequences has been investigated. Clones containing DYZ3 or DYZ5 sequences were found in libraries at about the frequency anticipated on the basis of their abundance in the genome, but clones containing DYZ1 sequences were under-represented and the three clones examined contained junctions between DYZ1 and DYZ2. One DYZ3 clone was quite stable and had a long-range structure corresponding to genomic DNA. All other clones had long-range structures which either did not correspond to genomic DNA, or were too unstable to allow a simple comparison. The effects of the transformation process and host genotype on YAC structural stability were investigated. Gross structural rearrangements were often associated with re-transformation of yeast by a YAC. rad1-deficient yeast strains showed levels of instability similar to wild-type for all YAC clones tested. In rad52-deficient strains, DYZ5 containing YACs were as unstable as in the wild-type host, but DYZ1/DYZ2 or DYZ3 containing YACs were more stable. Thus the use of rad52 hosts for future library construction is recommended, but some sequences will still be unstable.
Comparative trial of low-dose, intradermal, recombinant- and plasma-derived hepatitis B vaccines.
The immunogenicity and reactogenicity of low-dose, recombinant DNA and plasma-derived hepatitis B vaccines were investigated in a prospective, double-blind, randomized, controlled trial. Volunteers (153) received either recombinant vaccine, 10 micrograms in 1 ml intramuscularly; plasma-derived vaccine, 2 micrograms in 0.1 ml intradermally or recombinant vaccine, 1 microgram in 0.1 ml intradermally at 0, 30, and 150 days. Peak geometric mean concentrations of antibody to hepatitis B surface antigen at day 200 were 1094, 387, and 43 mIU/ml, respectively. By day 360, these concentrations had fallen to 346, 124, and 19 mIU/ml, respectively (P less than .05 between groups both dates). Number of subjects with antibody greater than or equal to 10 mIU/ml at day 200 was similar between the 10-micrograms recombinant and 2-micrograms plasma-derived groups (94% vs. 90%), while only 78% of the 1-microgram recombinant group had protective concentrations of antibodies (P less than .05). Erythema and induration occurred in most subjects in both intradermal groups, while pain was prominent at the intramuscular site especially after the second dose. Thus, plasma-derived vaccine, 2 micrograms in 0.1 ml intradermally, appears to be an acceptable cost-saving method for hepatitis B immunization, while recombinant-derived vaccine, 1 microgram in 0.1 ml intradermally, produced less satisfactory results.
Inside politics.
Explore the source record for details and available documents.
Suppressant effects of selective 5-HT2 antagonists on rapid eye movement sleep in rats.
The effects of the novel, highly selective serotonin-2 (5-HT2) antagonists, ICI 169,369 and ICI 170,809, on 24 h EEG sleep-wake activity were studied in the rat. Both compounds caused a dose-related increase in the latency to rapid eye movement sleep (REMS) and significantly suppressed cumulative REMS time up to 12 h postinjection. In contrast, neither drug disrupted slow-wave sleep continuity in as much as the latency to non-REMS (NREMS) and cumulative NREMS time were unchanged. However, at the highest dose tested (20 mg/kg) ICI 170,809 did produce a significant increase in total NREMS time during the second half of the sleep-awake cycle. These results demonstrate effects of selective 5-HT2 antagonists on sleep in rats which appear to be specific for REMS behavior, suggesting that the priming influence of serotonin on REMS may involve 5-HT2 receptor subtypes. The relationship between the REMS suppressant actions of these compounds and their consideration as therapeutic agents in depression is discussed.
Cervical cancer in Pacific island Polynesians.
Explore the source record for details and available documents.
Prevalence of von Recklinghausen neurofibromatosis in Dunedin, New Zealand.
A point prevalence study of von Recklinghausen neurofibromatosis (NF-1) was undertaken in greater Dunedin, New Zealand, having a base population of 113,700. A total of 52 individuals with NF-1 were identified, for a crude prevalence estimate of 45.7 per 100,000 (95% confidence interval 31.6-59.8 per 100,000) or 1 in 2,190 and an age-standardized prevalence of 48.5 per 100,000 (95% confidence interval 34.7-62.4 per 100,000) or 1 in 2,062. This is the highest prevalence estimate reported to date. This is presumed most likely to be due to a small population effect. The prevalence of NF correlated with age, being greatest among those aged 20-29 years and relatively low among those 60 or more years of age.
A strategy for the control of malignant melanoma in New Zealand.
Explore the source record for details and available documents.
High-mass dimuon production in p-barN and pi -N interactions at 125 GeV/c.
Explore the source record for details and available documents.
Changes in rat liver N-hydroxy-2-acetylaminofluorene aryl sulfotransferase activity at early and late stages of hepatocarcinogenesis resulting from dietary administration of 2-acetylaminofluorene.
The ability of 2-acetylaminofluorene (AAF) to mediate a loss in N-hydroxy-AAF (N-OH-AAF) aryl sulfotransferase activity when fed to male Sprague-Dawley rats was examined at early and late stages of hepatocarcinogenesis. Administration of 0.05% AAF in the diet for 1 week caused liver N-OH-AAF aryl sulfotransferase activity to decrease to 15 +/- 5% of that for liver from non-carcinogen-fed rats, and the activity remained low throughout 19 weeks of AAF feeding. When rats were fed AAF diet for 3 weeks, then placed on a control diet, liver N-OH-AAF aryl sulfotransferase activity returned to normal levels within 3 weeks. In contrast, when rats were fed AAF for 19 weeks, then placed on control diet for an additional 10 weeks, little or no recovery of N-OH-AAF aryl sulfotransferase activity was observed in cytosols from whole livers or isolated hyperplastic nodules, respectively. These findings suggest two types of AAF-mediated decreases in sulfotransferase activity: (a) a decrease observed early in the initial stages of AAF feeding which returns to normal levels when AAF is removed from diet, and (b) a persistent decrease in activity following long term AAF administration.
In vitro studies with ICI 169,369, a chemically novel 5-HT antagonist.
ICI 169,369 is a chemically novel 5-HT antagonist that has higher affinity for the 5-HT2 binding sites in rat cortex than it has for 5-HT1 sites (Ki 1.79 x 10(-8) and 1.58 x 10(-6) M, respectively). In isolated tissue preparations ICI 169,369 was shown to be a competitive antagonist of 5-HT on the rabbit aorta, pig coronary artery and rat caudal artery. In the latter preparation it had a similar pA2 value to ketanserin (pA2 8.18 +/- 0.5 and 8.42 +/- 0.06, respectively). Unlike ketanserin, which was inactive, ICI 169,369 was a non-surmountable antagonist at the rat stomach fundus 5-HT 'D' receptor, recently reclassified as 5-HTIC. It was inactive (greater than 10(-6) M) at the 5-HT3 receptors found in the isolated perfused rabbit heart and the myenteric plexus of the guinea-pig ileum. At receptors other than those for 5-HT (alpha 1, alpha 2, beta 1, beta 2, H1, H2 and muscarinic), ICI 169,369 was inactive at concentrations of either 10(-6) or 10(-5) M. Thus the profile of ICI 169,369 should make it useful in the analysis of the role of 5-HT in physiological and pathological states.