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J H Pearn

Publications and source records attributed to J H Pearn.

At least 37 records · Page 2Linked to original sources
PubMed1989

Childhood deaths in Down's syndrome. Survival curves and causes of death from a total population study in Queensland, Australia, 1976 to 1985.

Data have been obtained from a total population study of diagnosed Down's syndrome cases born in Queensland between 1976 and 1985. Survival curves show a survival rate to one year of 87.4% and no significant differences in such patterns over the two five year periods of the study. Survival curves comparing maternal age at birth, sex of the infant, and locality of birth also indicate that early death is unrelated to any of these factors. Congenital heart disease and respiratory infection are the most common causes of infant death.

Australia↗
PubMed1988

The use of field-inversion gel electrophoresis for deletion detection in Duchenne muscular dystrophy.

Deletion is a common cause of Duchenne muscular dystrophy (DMD). Field-inversion gel electrophoresis, in conjunction with Southern blot hybridization, was used to detect large SfiI DNA fragments in the DMD locus. Two unrelated boys with DMD were found to have abnormal sized DNA fragments resulting from deletions. Some of the female relatives of these patients were also shown by this method to have deletions in the DMD locus.

Chromosome Deletion↗
PubMed1987

Prenatal cytogenetic diagnosis--a current audit. A review of 2000 cases of prenatal cytogenetic diagnoses after amniocentesis, and comparisons with early experience.

An audit of 2000 cases of prenatal cytogenetic diagnoses is presented. This comprises two consecutive series of 1000 cases (1974-1980 and 1980-1983). Chromosomal studies were performed after mid-trimester amniocentesis. For both series detailed results of the reasons for referral and the outcome of laboratory studies and pregnancy follow-up (in 95% of cases) are presented. In current practice 75% of prenatal cytogenetic diagnoses were for advanced maternal age. Ten per cent of tests were undertaken because of a family history of Down's syndrome. The detection rate of chromosomal abnormality in prenatal cytogenetic diagnoses was 2.06%. Two per cent of amniotic cell cultures failed to grow, necessitating a repeat amniocentesis. The rate of culture failure due to undefinable causes was 0.55%. Fetal loss after amniocentesis for prenatal cytogenetic diagnosis at 16 weeks' gestation has halved since 1980, with a current miscarriage rate of 0.6% within four weeks of the procedure. One maternal death (as a result of amniotic fluid embolism) and one case of amnionitis occurred in the first series of 1000 consecutive cases (up to 1980), but no such complication has occurred since. Secular trends in the indications for referral, laboratory complications, clinical outcome and diagnostic patterns are presented.

Abortion, Induced↗
PubMed1987

Prenatal cytogenetic diagnosis. Amniotic cell culture versus chorionic villus sampling.

Chorionic villus sampling is under evaluation throughout the world. Amniocentesis with amniotic cell culture is reliable for the diagnosis of certain types of genetic disease in the second trimester, and has been the subject of extensive clinical and laboratory audit. Chorionic villus sampling has the advantage of the early diagnosis (for example, at 10 weeks) of chromosomal abnormalities, a shorter delay with results after the diagnostic procedure, and is, for some couples, a more socially and morally acceptable method of antenatal diagnosis. In current experience, the disadvantages of chorionic villus sampling include an increased fetal loss and an increased diagnostic error rate. Another factor is the early diagnosis of fetuses with chromosomal abnormalities--a proportion of whom would have miscarried spontaneously before being detected at an amniocentesis at 16 weeks. This has implications for an increased rate of therapeutic terminations of pregnancy. Chorionic villus sampling and amniotic cell culture are discussed and comparisons are drawn that concern the clinical advantages and diagnostic issues which are inherent in each method of prenatal diagnosis.

Abortion, Induced↗
PubMed1987

A corneal abnormality associated with trisomy 8 mosaicism syndrome.

Eye abnormalities are a significant feature of trisomy 8 mosaicism syndrome. This paper gives the first account of the specific histopathology of a corneal opacity which is characteristic of this syndrome. The importance of early recognition is stressed because of potential therapeutic visual improvement. The necessity of including mosaic trisomy 8 in the differential diagnosis of such corneal opacities is illustrated by this case.

Chromosomes, Human, Pair 8↗
PubMed1987

Diagnostic trends in childhood chromosome abnormalities and their implications--a total population eight-year survey from Queensland, Australia.

The data from an ongoing total population survey of all diagnosed chromosome anomalies in Queensland, Australia have been presented for an 8-year period (1976-83). A total of 760 patients was diagnosed, principally autosomal trisomies (431) and sex chromosome abnormalities (126). Nearly half of total childhood diagnoses (up to 14 years) were made in the first week. Virtually all expected cases of autosomal trisomies were detected in the first month. The largest component of the pool of unrecognized childhood disorders in this study was the sex chromosome group. This failure of detection has implications in terms of potentially beneficial hormone treatment and predisposition to neoplasia.

Adolescent↗
PubMed1986

Cerebral astrocytoma as a complication of acute lymphoblastic leukaemia.

A boy who developed acute lymphoblastic leukaemia at the age of two years and 10 months had several central nervous system relapses, and received two courses of cranial irradiation, each of 24 Gy, in addition to systemic and intrathecal chemotherapy. Nearly 10 years after the onset of his leukaemia he developed a brain stem astrocytoma from which he died. This appears to be a rare occurrence, and the role of the treatment in the induction of his second tumour is discussed. The need for the long-term follow-up of cancer patients after apparent cure is emphasized.

Astrocytoma↗
PubMed1985

Prenatal cytogenetic diagnosis: medical and social implications. Indications, acceptance by doctors and patients, impact and cost: a 10-year review.

Prenatal cytogenetic diagnosis has been in widespread use for a decade, and access to it has been determined by medical attitudes towards what constitutes "high risk", and by pragmatic questions about the logistics of delivering a new diagnostic test to as many couples as costs will allow. The most common indication - advanced maternal age - has led to different access criteria in various parts of Australia. Factors such as socioeconomic status, education, and religion affect the acceptance of prenatal cytogenetic diagnosis from the point of view both of patients and of the doctors who care for them. Cost-benefit analyses conducted elsewhere indicate that, in purely monetary terms, it is probable that prenatal cytogenetic diagnosis is cost-effective if offered to all couples in which the woman is over the age of 32 years. An assessment of the impact of prenatal cytogenetic diagnosis on the birth incidence of major chromosomal abnormalities, particularly Down's syndrome, indicates that the maximum reduction which might be achieved in current practice is 30%.

Abortion, Induced↗
PubMed1985

Prolonged intensive therapy after snake bite. A probable case of envenomation by the rough-scaled snake.

A case of snake-bite envenomation, probably by the rough-scaled snake (Tropidechis carinatus), in a 9-year-old boy is reported which we believe to represent the most severe and prolonged case yet of non-fatal snake-bite envenomation in a human. The initial clinical features included loss of consciousness within minutes of the bite, followed by a period of partial recovery. The child subsequently developed total body paralysis, acute renal failure, and gross rhabdomyolysis. Artificial ventilation was maintained for 10 weeks; muscle paralysis and paresis persisted for 18 weeks before neuromuscular function returned to normal. Recovery occurred in centripetal fashion, the respiratory muscles and the palatal muscles being the last to recover. Acute renal failure persisted for 18 days and was treated by peritoneal dialysis. Some beneficial effects were seen even when antivenom was given 90 hours after the bite, but gross rhabdomyolysis caused by this species is not prevented by the administration of antivenom after 60 hours. It is concluded that if life can be sustained for 10 weeks by artificial ventilation, normal intellectual and neuromuscular recovery is possible in such cases.

Acute Kidney Injury↗
PubMed1985

Survival in trisomy 18. Life tables for use in genetic counselling and clinical paediatrics.

Clinical management of neonates with Trisomy 18 depends on a knowledge of life expectancy. True estimates of potential life span are required for genetic counselling purposes when parents interpret the genetic threat, not only in terms of the mathematical odds involved, but also in terms of the quality and length of life of an affected infant, should such be born. This paper reports the findings from a study to generate life tables for Trisomy 18. This study is a total population study over 10 years based on a primary population of 2.2 million. Forty-eight cases of Trisomy 18 were identified, five at amniocentesis. Four of the 43 clinical cases (9%) were mosaics. The median life expectancy for live-born infants was five days (range one hour to 18 months). Mean age at death was 48 days. Life tables, by sex and by sub-types (associated congenital abnormalities) are presented. The annual incidence is 14 per 100,000 total births, with a prevalence estimate of 0.06 per 100,000 total population.

Chromosomes, Human, 4-5↗
PubMed1985

Secular trends in fatal and disabling child trauma.

Types and rates of childhood accidents are constantly varying. From the point of view of the potential child victim, the danger-safety equilibrium is disturbed by changes in lifestyles, availability of new consumer goods, and changes in social order. Balance is achieved by the implementation of preventive measures, particularly safety legislation. 'Old' hazards affecting children in pre-industrial societies can re-emerge at any time as wealthy sophisticated societies aspire to recapture the delights of open space, the water, and 'country-style' living. Age-specific fatal accident rates are given for Australian children for the period 1960-1982. Whereas the total child (1-14 y) death rate has fallen from 159 per 100000 (in 1960) to 86 (in 1982), road traffic deaths have risen from 8.3-11.7 (1-4 year olds) and have remained static (8.3-8.9) for 5-14 year old children. Drowning in older children has been reduced, but drownings among toddlers are still high (9.2 in 1960; 11.7 in 1982). The causes of secular trends, and factors which are known to influence these, are discussed.

Accidents, Traffic↗
PubMed1985

Herbicides and congenital malformations: a review for the paediatrician.

The herbicides 2, 4, 5-T and 2, 4-D are relatively non-toxic to primates, in acute exposure. Dioxins, which have occurred as impurities in these two herbicides, manifest universal biological toxicity. The best understood dioxin TCDD, has, in susceptible strains of mice, a very low teratogenic minimal effective dose of 1-10 micrograms/kg. This fact has engendered an era of uncertainty about the potential teratogenic effects of herbicides, in the context of potential human exposure. This paper reviews current knowledge concerning herbicide teratogenesis following maternal exposure. Because of species specificity of teratogenic agents, it is not possible to extrapolate from effects in lower animals to potential effects in humans. It remains a fact however that all proven human teratogens have parallel animal models. Following maternal exposure to herbicides and to dioxins, it has not been possible to produce teratogenic effects in primates, although fertility may be affected. Epidemiological reports from Hungary, Italy (the ICMESA accident), New Zealand, the United States, Europe and Australia have not revealed any positive evidence to indicate that a human herbicide teratogenic syndrome exists.

2,4,5-Trichlorophenoxyacetic Acid↗
PubMed1985

Current controversies in child accident prevention. An analysis of some areas of dispute in the prevention of child trauma.

The rate of serious child trauma has not been significantly reduced in the last two decades. During this time, both infant mortality rates and the total child death rate have fallen by 30%. Child trauma, as a relative contributor to child mortality in general, continues to increase. Effective prevention depends on a detailed understanding of causes, an appraisal of options, and cost-benefit audit of intervention programmes. Controversial themes are common in accident prevention work; controversies relating to child safety result from both an absence of data about detailed causes, and from philosophical conflicts about whose responsibility it is to prevent child trauma, and who will bear the cost. Five controversial areas have been selected and are discussed to illustrate these current problems. These are the inevitability of accidents, the loss of personal freedom that occurs in the regulation of a safe environment, "drownproofing" of infants, questions of sporting injuries involving children and the progressive upgrading of rules to make sports safer, and problems relating to the assessment of true exposure risks.

Accident Prevention↗
PubMed1984

Venom of the Australian rough-scaled snake, Tropidechis carinatus: lethal potency and electrophysiological actions.

A series of experiments to define the lethal potency (LD50) and electrophysiological properties of the venom of the Australian Rough-scaled Snake (Tropidechis carinatus) are described. Crude pooled venom contains at least five fractions which were separated using liquid chromatography and high pressure liquid chromatography techniques (Fractions I-V). LD50 studies are reported using each of these fractions, with data for both adult and neonatal mice. Fraction I (mol. wt greater than 100,000) was essentially non-toxic. Fraction IV (mol. wt less than or equal to 10,000) and Fraction V (mol. wt less than 1,000) were potent toxic components with LD50'S (s.c. injection; fraction in 0.1% bovine serum albumin and 0.85% saline; neonatal mice) of 0.04 mg/kg and 0.06 mg/kg respectively. LD50'S for the whole crude venom were similar in both adult and neonatal mice. Electrophysiological studies using a Bulbring preparation (rat isolated phrenic nerve-hemidiaphragm) indicated that Fractions I, IIa and IIb were inactive. Fraction IV (mol. wt less than or equal to 10,000) caused rapid neuromuscular blockade which appeared to be irreversible. Neurophysiological experiments with a rat isolated extensor digitorum longus muscle preparation suggested that the major toxic activity of the whole venom resides in Fractions III and IV, and that both of these fractions have presynaptic and postsynaptic action.

Animals↗