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Biomedical subjects

J Randall

Publications and source records attributed to J Randall.

At least 19 recordsLinked to original sources
PubMed1992

Prospective study of short and long regimens of gonadotropin-releasing hormone agonist in in vitro fertilization program.

OBJECTIVE: To assess the usefulness of a short regimen in ovulation induction in an in vitro fertilization (IVF) program. DESIGN: A prospective randomized trial was set up to compare long and short regimens of gonadotropin-releasing hormone agonist administration for ovulation induction in IVF. SETTING: Aberdeen Assisted Reproduction Unit. PATIENTS: Eighty-seven patients undergoing IVF were randomized between the two protocols. Stimulation regimen was the only variable being tested. MAIN OUTCOME MEASURES: Stimulation response and occurrence of luteinizing hormone (LH) surges. RESULTS: There was no difference in the stimulation requirements, response to stimulation, number of follicles aspirated, or the number of oocytes obtained. The fertilization rates, number of embryos transferred, and pregnancy rates were also similar in both groups. Like the long regimen, it prevents the occurrence of a premature LH surge. CONCLUSION: The short regimen is a useful and cheaper alternative in ovarian stimulation of patients undergoing IVF.

Adult↗
PubMed1991

Use of emergency services by unaccompanied minors.

STUDY OBJECTIVE: The objective of the study was to describe the use of emergency services by minors who are unaccompanied by their parents or guardians and how they are managed in emergency departments. DESIGN: Self-administered survey. TYPE OF PARTICIPANTS: The ED directors of 71 emergency medicine training programs, 82 Michigan community EDs, and 56 pediatric EDs. MEASUREMENTS AND MAIN RESULTS: One hundred eighteen (58%) surveys were returned. A median of five unaccompanied minors (range 0.2 to 150) were seen weekly by responding EDs. Pediatric EDs saw the most unaccompanied minors weekly (ten) compared with training programs (five) and community EDs (three) (P less than .01). Emergency medicine training programs had the greatest percentage (3.0%) of minors who were unaccompanied compared with pediatric EDs (2.2%) and community EDs (2.6%) (P less than .05). For all conditions surveyed, only 3.8% of patients would be refused medical care without parental consent. However, 36.8% of patients would have medical care delayed even for conditions that might be painful or harmful if left untreated for some time. Most EDs (85.5%) screen patients and treat those who are acutely ill, but some (11.1%) treat all regardless of severity. CONCLUSION: Protocols should be developed for unaccompanied minors to ensure that delays in obtaining consent do not jeopardize the child and that the rights of minors for confidentiality and consent are recognized.

Adolescent↗
PubMed1991

Xanthine oxidase is not a major source of free radicals in focal cerebral ischemia.

Xanthine oxidase (XO) has been proposed as an important source of free radicals during ischemia. This enzyme normally exists as a dehydrogenase (XD), but it is converted to XO in some ischemic tissues. Recently, treatment of animals with the XD and XO inhibitor allopurinol or with free radical scavengers before cerebral ischemia has been shown to reduce brain injury. Therefore, we studied conversion of XD to XO in three ischemic and nonischemic brain regions during focal cerebral ischemia resulting from permanent occlusion of the middle cerebral artery (MCAO) in anesthetized rats. In nonischemic brain, 16-22% of the enzyme was in the XO form. After 24 h of ischemia this value was not significantly different (10-15%). Neither the total activity of XO nor that of XD changed, indicating that there was no irreversible conversion of XD to XO. To further explore the possible role of XO, we examined the effect of various doses of allopurinol (5, 20, or 100 mg/kg given 1 h before MCAO or 100 mg/kg given 48, 24, and 1 h before MCAO) on uric acid accumulation, brain edema formation, and cerebral blood flow (CBF) 24 h after MCAO. All but the lowest dose of allopurinol greatly reduced the appearance of uric acid in the ischemic brain; however, only the highest dose of allopurinol had any beneficial effect on brain edema. This reduction in brain edema occurred without a significant improvement in CBF. Thus XO is probably not an important source of free radicals in this model of focal cerebral ischemia.

Allopurinol↗
PubMed1990

A primary preventive approach to children's drug refusal behavior: the impact of rehearsal-plus.

The effectiveness of a short-term prevention program to increase drug refusal behavior in a school-age population was assessed. Forty-two third-grade children were randomly assigned to one of three groups: rehearsal-plus, traditional, or attention control. Children in the rehearsal-plus group were taught specific drug refusal techniques and appropriate social skills, and were provided a rationale for each response. This procedure included behavioral training and elaborative rehearsal. Training occurred in four socially validated situations corresponding to settings where children were likely to be offered drugs. The traditional procedure consisted of instructions derived from a "Just Say No" drug program. Assessment focused on specific refusal behaviors, procedural knowledge, and self-efficacy. Significant gains in desired functioning and appropriate behavioral and social skills were found. The effectiveness of the rehearsal-plus procedure as a method of increasing adaptive responding in dangerous and/or anxiety-arousing situations is discussed.

Behavior Therapy↗
PubMed1989

The frequency of chromosome anomalies in human preimplantation embryos after in-vitro fertilization.

Previous studies have reported chromosome aberrations in human pre-embryos after in-vitro fertilization (IVF). Although the reason for these abnormalities is not clear, there is evidence that they can arise during gametogenesis, fertilization or cleavage. The present study has examined further the incidence of chromosome abnormalities in human pre-embryos after IVF, using oocytes recovered from normal volunteer women and from women undergoing infertility treatment in an embryo-replacement programme. Chromosome preparations were performed for 75 pre-embryos. Of these 35 (47%) gave at least one metaphase in which analysis was possible. The overall incidence of abnormal pre-embryos was 40% (14/35). The absolute frequency of aberrations was 9% for trisomies, 3% for polyploidies, 26% for structural anomalies and 3% for hypodiploidies. Five pre-embryos were found to be mosaics, three of which had each one trisomic metaphase. In five of the pre-embryos multiple anomalies were found. In 13 of the 14 abnormal pre-embryos the aberrations were found in only one metaphase. The present study demonstrates that trisomic mosaicism may not be a rare event in human pre-embryos. Further evidence is provided that mitotic non-disjunction is important for the production of aberrations in human pre-embryos.

Blastocyst↗
PubMed1989

The frequency of chromosome anomalies in human unfertilized oocytes and uncleaved zygotes after insemination in vitro.

Data on first trimester human abortions have shown chromosome aberrations in approximately 50% of the cases, most of which were trisomies. More than 80% of these trisomies have been attributed to an error in the oocyte. In this study we investigated the frequency of chromosome anomalies in 44 human unfertilized oocytes and 13 uncleaved zygotes after insemination in vitro. The oocytes were aspirated from preovulatory follicles in parous volunteer donors and patients participating in an embryo replacement programme. Thirty cases could be analysed, 18 of which (60%) carried a chromosome abnormality. There were two hyperhaploidies (6.7%), four hypohaploidies (13.3%), three polyploidies (10%), six with structural aberrations (20%) and five diploidies (16.7%). The incidence of these abnormalities, except for the structural anomalies, was similar to that reported previously. The higher frequency of structural aberrations in the present study may be related to delayed cytogenetic analysis for up to 48 h after insemination.

Abortion, Spontaneous↗
PubMed1988

Installation and use of a neodymium-YAG laser in a urology department.

We report our experience in setting up a urological laser unit. An operating theatre was upgraded to include the required safety features and a neodymium-YAG laser was installed. A preliminary study using cadaver bladders was performed to establish the technique of cystoscopic laser application. We treated 55 bladder tumours in 12 patients by laser coagulation, with total destruction of 54 tumours and no serious complications; 6 patients developed recurrent tumours. Twenty-one patients underwent surgery with the contact laser scalpel. The instrument proved slow but effective, with excellent haemostasis and almost painless wounds. Healing was delayed in 2 cases but there were no wound infections. All wounds healed with good cosmetic scars. The neodymium-YAG laser is an effective means of destroying superficial non-invasive bladder tumours endoscopically and can also be used in conjunction with a laser scalpel for open surgery.

Aged↗
PubMed1987

Ureteropyelostomy: a simple and effective treatment for symptomatic ureteroureteric reflux.

Partial ureteric duplication may cause delayed drainage of urine from the upper tracts because of ureteroureteric "see-saw" reflux. This can be eliminated by the procedure of ureteropyelostomy, in which the partially duplicated ureter is converted into a bifid renal pelvis. This operation leaves a short anastomotic suture line and has a low complication rate. We report seven patients who have undergone ureteropyelostomy for symptomatic ureteroureteric reflux. All remain symptom-free after follow-up for a minimum of 1 year.

Anastomosis, Surgical↗
PubMed1986

Haemorrhage and perforation of gastrointestinal neoplasms during chemotherapy.

Gastrointestinal haemorrhage and perforation are known complications of cytotoxic therapy for chemosensitive tumours involving the wall of the gut, in particular non-Hodgkin's lymphoma. These complications can be avoided by aggressive surgery before chemotherapy is started. When they do occur, early operative intervention is essential to reduce morbidity and mortality. We report 4 cases in whom delay in diagnosis and surgery led to 3 deaths and suggest a policy for the management of such cases in the future.

Adult↗
PubMed1985

Naloxone potentiates the depressant effect of chlordiazepoxide on spontaneous activity in mice.

Recent reports suggest that at least some of the behavioural effects of benzodiazepines may involve interaction with endogenous opioid mechanisms. In the present study, chlordiazepoxide (CDP, 10-20 mg/kg, i.p.) induced dose-dependent reductions in spontaneous locomotor activity and rearing in mice. Although naloxone (1 mg/kg) was itself without effect, and did not alter behavioural changes induced by the lower dose of CDP, it enhanced the depressant effects of 20 mg/kg CDP on locomotor activity. Results are discussed in relation to previous studies in which opiate antagonists have been found to block or to have no effect upon behavioural actions of benzodiazepines.

Analysis of Variance↗
PubMed1985

Hot-plate learning in mice is unaltered by immediate post-training administration of naloxone, naltrexone or morphine.

Repeated exposure to the hot-plate assay results in shorter response latencies in both rats and mice. In view of the postulated role of endorphins in memory processes, the present study examined the effects of immediate post-trial opiate-induced manipulations on this phenomenon of hot-plate learning. In experiment 1, adult male mice were injected with naloxone (0.1-10.0 mg/kg, i.p.) immediately after initial hot-plate testing and were reassessed 24 and 48 hr later. In experiment 2, mice were similarly treated with either naltrexone (0.1-10.0 mg/kg) or morphine (0.5-5.0 mg/kg) and retested 48 and 72 hr later. Results indicated a potent training effect in all groups but failed to reveal any significant effects of drugs. These data are inconsistent with a role for endorphins in hot-plate learning and, further, may question the generality of the involvement of opioids in memory processes.

Animals↗
PubMed1982

The measurement and interpretation of Brillouin scattering in the lens of the eye.

Brillouin scattering from hypersonic waves in the eye lenses of many animals has been observed with a multipass Fabry Perot interferometer. The measured values of speed and attenuation range widely among the different species and in different parts of any one lens. These variations correlate broadly with the observed stiffness and the densities that have been measured with a graded column. From the spectroscopic and density measurements high-frequency elastic moduli may be derived. The results are also evaluated at a macromolecular level in terms of scattering of hypersonic waves from spherical entities composed of the crystallins and their aggregates. Reasonable agreement is obtained for the hypersonic speed for lower protein concentration; the hypersonic attenuation and variation with scattering vector are consistent with the presence of large aggregates (of order 100 nm radius) in certain of the materials.

Animals↗
PubMed1981

Small-angle neutron scattering studies of the conformation of myeloma protein MOPC315 and its Fab fragment, and the interaction with a monovalent dinitrophenyl hapten.

The first small-angle scattering study of an immunoglobulin A is reported. Neutron measurements have been made to determine conformational parameters of the mouse myeloma protein MOPC315 and to relate these to previous immunoglobulin G results. Use of the contrast method shows that the MOPC315 IgA molecule is not simply globular, that it has a dry volume of 220.0 +/- 4.5 nm3 corresponding to a mass density of 1.275 +/- 0.025 g cm-3 and that its full and cross-sectional radii of gyration, corrected for concentration dependence, are 7.97 +/- 0.07 nm, 2.40 +/- 0.08 nm and 1.33 +/- 0.07 nm respectively. Similar study of its Fab fragment gives a dry molecular volume of 69.0 +/- 0.7 nm3, a mass density of 1.285 +/- 0.015 g cm-3 and uncorrected radii of gyration that are consistent with those of the parent and support an overall "T" or "Y" conformation in solution. Addition to saturation of a small monovalent dinitrophenyl hapten leaves the dry volume of the whole molecule unaltered, but may slightly lower one or more of its radii of gyration. The significance of this finding is discussed. Comparative studies with rabbit anti-dinitrophenyl immunoglobulin G antibody suggest a different initial conformation but similar consequences of hapten binding, which, if real, are probably unrelated to classical complement fixation.

Amino Acid Sequence↗