Peopling of Sahul: mtDNA variation in aboriginal Australian and Papua New Guinean populations.
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We examined genetic affinities of Aboriginal Australian and New Guinean populations by using nucleotide variation in the two hypervariable segments of the mtDNA control region (CR). A total of 318 individuals from highland Papua New Guinea (PNG), coastal PNG, and Aboriginal Australian populations were typed with a panel of 29 sequence-specific oligonucleotide (SSO) probes. The SSO-probe panel included five new probes that were used to type an additional 1,037 individuals from several Asian populations. The SSO-type data guided the selection of 78 individuals from Australia and east Indonesia for CR sequencing. A gene tree of these CR sequences, combined with published sequences from worldwide populations, contains two previously identified highland PNG clusters that do not include any Aboriginal Australians; the highland PNG clusters have coalescent time estimates of approximately 80,000 and 122,000 years ago, suggesting ancient isolation and genetic drift. SSO-type data indicate that 84% of the sample of PNG highlander mtDNA belong to these two clusters. In contrast, the Aboriginal Australian sequences are intermingled throughout the tree and cluster with sequences from multiple populations. Phylogenetic and multidimensional-scaling analyses of CR sequences and SSO types split PNG highland and Aboriginal Australian populations and link Aboriginal Australian populations with populations from the subcontinent of India. These mtDNA results do not support a close relationship between Aboriginal Australian and PNG populations but instead suggest multiple migrations in the peopling of Sahul. (+info)
Archean molecular fossils and the early rise of eukaryotes.
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Molecular fossils of biological lipids are preserved in 2700-million-year-old shales from the Pilbara Craton, Australia. Sequential extraction of adjacent samples shows that these hydrocarbon biomarkers are indigenous and syngenetic to the Archean shales, greatly extending the known geological range of such molecules. The presence of abundant 2alpha-methylhopanes, which are characteristic of cyanobacteria, indicates that oxygenic photosynthesis evolved well before the atmosphere became oxidizing. The presence of steranes, particularly cholestane and its 28- to 30-carbon analogs, provides persuasive evidence for the existence of eukaryotes 500 million to 1 billion years before the extant fossil record indicates that the lineage arose. (+info)
Epidemiological, clinical, and laboratory aspects of pertussis in adults.
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In populations without immunization, pertussis is a high-incidence, endemic disease with cyclic epidemic peaks occurring every 2-5 years. The universal use of pertussis vaccines in children results in a marked reduction in incidence, but the frequency of disease cycles does not lengthen. This indicates that the organism (Bordetella pertussis) remains prevalent in the population. Studies of prolonged cough illnesses in adolescents and adults indicate that between 12% and 32% are the result of B. pertussis infection. Serological survey data indicate that all adults have been previously infected, and IgA antibody studies suggest that infections in adults are as frequent in the United States, where pertussis has been controlled, as in Germany, where pertussis has been epidemic. Because of the apparent reservoir of B. pertussis infections in adolescents and adults, I believe that B. pertussis circulation cannot be controlled by our present childhood immunization program. Acellular pertussis vaccines make adolescent and adult booster immunization programs possible, and these could lead to a decrease in the circulation of the organism. (+info)
Management of women with recurrent genital herpes in pregnancy in Australia.
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OBJECTIVE: To document clinical practice for the management of recurrent genital herpes in pregnant women in Australia. DESIGN AND PARTICIPANTS: A questionnaire to all doctors associated with the Royal Australian College of Obstetricians and Gynaecologists. MAIN OUTCOME MEASURES: Policies for antenatal herpes screening, circumstances in which delivery by caesarean section was considered appropriate, and the use of aciclovir during pregnancy. The results were analysed by college status, sex, and whether the doctor worked in a public or private facility. RESULTS: 2855 (67.3%) obstetricians returned questionnaires. 696 (34.3%) stated that their hospital had a policy for managing recurrent genital herpes in pregnancy: 44.5% examined the genitalia and 33.8% took cultures during pregnancy. Fellows were more likely to examine the genitalia (87% v 37%, p < 0.001), and more likely to perform antenatal viral cultures than members (75% v 30%, p < 0.001). Doctors working at private hospitals were significantly more likely to take viral cultures than doctors in public hospitals (39% v 33% p < 0.05). Doctors were asked to consider five scenarios and judge whether caesarean section would be appropriate. 96% considered that a caesarean section was appropriate in women with active herpes at the onset of labour. In the case of a recurrence of genital HSV at the time of presentation with ruptured membranes longer than 4 hours, diplomats (79%) were significantly more likely to recommend a caesarean section than fellows (64%), members (63%), or trainees (49%) (all p < or = 0.001). Where there were positive viral cultures before the onset of labour fellows (45%) were more likely than members (29%) (p = 0.005), males (62%) were more likely than females (55%) (p = 0.03), and doctors working in private hospitals (69%) were more likely than those in the public sector (54%) (p < 0.001) to recommend caesarean section. CONCLUSION: There is considerable divergence of opinion regarding the appropriate management of recurrent genital herpes in pregnancy. The implementation of management guidelines would provide consistency of care. (+info)
The sydney multicentre study of Parkinson's disease: progression and mortality at 10 years.
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OBJECTIVES: To report on a 10 year follow up of patients with idiopathic Parkinson's disease, particularly with respect to mortality and the effect of early treatment with bromocriptine. METHODS: The patients are from the 149 new patients recruited for a double blind, randomised study of low dose levodopa-carbidopa versus low dose bromocriptine. Patients were examined neurologically at least yearly. Neuropsychological examinations were performed at 0, 3, 5, and 10 years. Mortality and cause of death in these patients were compared with the Australian population using standardised mortality ratios (SMRs). Mortality and disease progression were compared by sex and treatment group. Predictors of death within 10 years, nursing home admission, and progression in Columbia score of >/=20 points were examined by logistic regression analysis. RESULTS: Thirteen patients were excluded as having atypical Parkinsonism and six were lost to follow up. All available patients have been followed up for 10 years. Fifty patients (38%) were dead by 10 years and 63 by the last follow up. The SMR was 1.58 for all patients (p<0. 001). There was no significant difference in SMRs between the sexes. The mean duration of disease until death was 9.1 years. Parkinson's disease was thought to have contributed substantially to the death of 30 patients. The most common cause of death was pneumonia. Women progressed at a similar rate to men until 8 years, when the severity of their disease as measured by Hoehn and Yahr stage became greater (p<0.05). Older age of onset correlated with increased risk of death but the SMR was increased even in those aged <70 years (SMR 1.80, p=0.03). Early use of bromocriptine did not reduce mortality or slow progression of disease. One quarter of all patients had been admitted to nursing homes by 10 years. Only four patients were still employed. CONCLUSIONS: Mortality in Parkinson's disease remains increased despite low dose levodopa-carbidopa therapy and no additional benefit was gained from early use of bromocriptine. Duration of disease was similar to that in the era before levodopa. (+info)
Extended tumour necrosis factor/HLA-DR haplotypes and asthma in an Australian population sample.
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BACKGROUND: Tumour necrosis factor (TNF) is a potent pro-inflammatory cytokine which is prominent in asthmatic airways. TNF shows genetic variations in secretion which are linked to polymorphisms in the TNF gene complex and the surrounding major histocompatibility (MHC) locus. These polymorphisms do not seem to be themselves functionally important. In these circumstances, the identification of disease associated haplotypes (combination of alleles on individual chromosomes) may narrow the search for polymorphisms which alter gene function. METHODS: TNF-308, LTalpha NcoI, and HLA-DRB1 polymorphisms were investigated for association with asthma, bronchial responsiveness, and medication use in 1004 subjects in 230 families from a general population sample. RESULTS: The common LTalpha NcoI*1/TNF-308*2/HLA-DRB1*03 haplotype, which was present in 11% of unrelated individuals, was weakly associated with asthma (OR = 1.38, p = 0.016, corrected for familial correlation). The rarer LTalpha NcoI*1/TNF-308*2/HLA-DRB1*02 haplotype, which was found in 0.6% of unrelated subjects, was more strongly associated with asthma (OR = 6.68, p = 0.002). This haplotype also showed association with bronchial hyperresponsiveness (OR = 21.9, p = 0. 0000) and the use of inhaled or oral steroids (OR 8.0, p = 0.04). CONCLUSIONS: The results of this study show only two extended TNF/HLA-DR haplotypes to be associated with asthma. The search for functional alleles responsible for an increased risk of asthma should concentrate on the LTalpha NcoI*1/TNF-308*2/HLA-DRB1*02 haplotype. (+info)
The fate of cryopreserved human embryos approaching their legal limit of storage within a West Australian in-vitro fertilization clinic.
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Human embryos can only be stored in the first instance for 3 years in Western Australia, according to the West Australian Reproductive Technology Act. Thereafter, an application must be made to the local regulatory body, the Reproductive Technology Council, for an extension. Of the 650 batches of embryos frozen between 8 April 1993 and 31 October 1995, 170 (26.2%) batches were still in storage after 2.5 years. A reminding letter was sent at this time to the couples to whom the embryos belonged, i.e. 6 months before the expiry of the initial storage period, asking for clarification of what was to be done with the embryos. A large proportion of patients (64.7%) chose to either extend the storage period or thaw and transfer the embryos. Curiously, more batches of embryos were discarded (18.8%) than donated to other couples (5.9%). Contact with the patients was lost in a small but significant proportion of cases; more of these had been unsuccessful in their treatment (20.4%) than had achieved a pregnancy (4.3%). (+info)
Molecular phylogeny and morphological homoplasy in fruitbats.
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The present study evaluates the evolutionary framework of the Old World fruitbats based on the cytochrome b and 16S rRNA mitochondrial gene sequences from a wide range of taxa. Phylogenetic analyses indicated that morphology-based subfamilies and most suprageneric groups are nonnatural assemblages. They also support the existence of an endemic African clade of fruitbats. The discrepancy between the evolutionary relationships yielded by molecular and morphological data sets may be, at least in part, explained by the recurrent retention of primitive morphology (Rousettus-like) across different lineages. The maintenance of primitive characters in different groups of flying foxes, as well as morphological convergence in nectar-feeding bats and possibly also in short-muzzle bats, may have led to high levels of homoplasy, resulting in misleading taxonomic arrangements. This may be particularly so with respect to high taxonomic levels based on morphological characters. (+info)