Biomedical subjects
Publications and source records attributed to I Johnston.
A newborn with paraplegia and evidence of a subarachnoid hemorrhage was found to have a spinal arteriovenous malformation. The arteriovenous malformation was managed by direct surgical obliteration. This patient is the youngest ever reported to have this disorder and the youngest so treated.
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A case, in which pregnancy (unfortunately ectopic) followed oocyte collection by an ultrasound technique, is reported. Nevertheless, the procedure is less invasive than laparoscopic follicular aspiration, does not require general or major regional anaesthesia, and is suitable for patients in whom access to the ovaries by means of laparoscopy is either not possible or severely restricted.
The effects of maternal preovulatory serum and human fetal cord serum supplement in culture medium in human in vitro fertilization and embryo development were compared in 208 cases over an 8-month period when there were no significant changes in other variables. A significantly higher pregnancy rate was observed in the fetal cord serum group despite no significant difference being found in fertilization and embryo cleavage rates. This suggests a difference in the health of the embryo cultured in different serum supplements.
A system for rapid selection of normal motile spermatozoa from poor semen samples is described. Analysis of the selected samples shows that there are significant improvements in the percentage motility, velocity and morphology. The final spermatozoa suspension of 0.5 ml is sufficient for the purpose of intrauterine AIH and IVF.
A study of peak flow variability was carried out among a population sample of 63 wheezy children aged 9-11 years. Recordings were made over 12 days at three times during the day--first thing in the morning, on returning home from school and at bedtime. Eighty nine per cent of the children had symptoms during the diary period. The mean amplitude (difference between the highest and lowest daily peak flow values) was 17% of the mean daily value (range 4-48%). By cosinor analysis the amplitude was 12% of the mean value (range 1-53%). In 65% of the children the lowest point of the daily rhythm as determined by cosinor analysis lay between midnight and 8am; the rhythm was, however, statistically significant in only fourteen individuals (22%). These levels of variability are considerably lower than those previously reported in hospital based studies of adult asthmatics. As a method of demonstrating variable airflow obstruction, which is the defining physiological characteristic of asthma, the use of a peak flow diary alone appears to be of limited value in children.
A simple technique for the evaluation of shunt function and cerebrospinal fluid (CSF) circulation in hydrocephalic patients is described. The method utilizes clearance rates of a radionuclide tracer injected into the lateral ventricle via an indwelling frontal catheter which is separate from the shunt apparatus. This permits an accurate assessment of drainage of ventricular CSF via the shunt, or the patency of normal or alternative CSF pathways where the shunt is malfunctioning.
A sensitive and specific radioimmunoassay was used to measure human chorionic gonadotropin (hCG) excretion in serial overnight urine samples in women having embryo transfer, in an in vitro fertilization program. Elevated hCG excretion suggestive of blastocyst implantation was detected in 17 of 121 women studied. When the results were corrected for interference by luteinizing hormone and other immunoreactive substances, implantation was detectable 8 to 9 days after fertilization in 20% of conceptual cycles, in 80% by days 12 to 13, in 93% by days 14 to 15, and in 100% by days 16 to 17. From a life table of human embryo development in culture, it was estimated that 37% of four-cell and 43% of eight-cell embryos reached the blastocyst stage. On the basis of these estimates and the elevated hCG from implanting blastocysts, it was concluded that 60% to 65% of uterine blastocysts either failed to implant or failed to produce measurable hCG.
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Evaluation of 192 cerebrospinal fluid shunts was performed using 1 mCi of technetium-99m DTPA which was injected into the shunt tubing. This was found to be a safe, simple method of evaluating shunt patency. No complications were noted with this procedure, nor was there any documented case of infection related to the injection of the isotope. The sensitivity of the test for evaluation of patency was 97%, specificity 90%, and accuracy 93%. Various patterns of tracer clearance are noted and discussed. The role on this test as an aid in making management decisions is detailed.
Three pregnancies have been achieved through in vitro fertilization (IVF) following clomiphene/human chorionic gonadotropin (hCG) stimulation monitored only with ultrasound. When the results of 120 stimulated cycles were compared with those from 213 spontaneous cycles during a one-year period, the clomiphene-ultrasound-hCG method led to a significantly higher laparoscopy rate as well as significantly better yields of mature oocytes and embryos for intrauterine transfer. The luteal phase was normal in the stimulated group. This ultrasound-monitored technique was simpler to manage and less costly and appears to be the current method of choice for obtaining oocytes for IVF.
A review of the in vitro fertilization and embryo transfer program between July 1979 and December 1980 at The Royal Women's Hospital, Melbourne, is presented. A total of 402 treatment cycles involving 186 patients have produced five pregnancies. Two pregnancies resulted from spontaneous ovulatory cycles and three from stimulated cycles. One live birth of a normal female child is reported. The protocol for both spontaneous and stimulated cycles and the problems that each produces are discussed. It is concluded that the stimulated cycle is to be preferred, because it allows higher rates of ovum recovery and embryo transfer. The fertilization and cleavage rates are the same for both methods. Associated research into in vitro blastocyst development, steroidogenesis in the corona cells, and the detection of other "early pregnancy factors" is presented and discussed. The paper concludes with a short statement on the ethical and moral problems posed by the research.
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Ovarian follicles in the immediate preovulatory period were measured with real-time or static ultrasound. Thirty-nine follicles were examined in thirty-six patients. In 29 spontaneous cycles the mean follicular diameter was 21.1 mm (range 17 to 25 mm) and the mean volume was 5.1 ml. In seven stimulated cycles the mean diameter was 18.4 mm and the mean volume was 3.5 ml. Laparoscopic needle aspiration of the follicular contents was performed within 12 hours of ultrasound examination in every case. Follicular dimensions based on the volume of aspirated fluid correlated well with the ultrasound measurements (r = 0.847; P < 0.001), which suggests that ultrasound is a useful technique for examining preovulatory follicular development.
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Bilateral intracavernous internal carotid artery aneurysms are described in a 3-year-old child. The etiology was uncertain, although the aneurysms may have been mycotic. As there was clinical and radiological evidence of progressive enlargement of both aneurysms, the more conventional forms of treatment were not applicable. A direct surgical approach was made to both aneurysms with exploration of the intracavernous portion of the internal carotid artery under deep hypothermia and cardiac arrest.