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Biomedical subjects

L Watson

Publications and source records attributed to L Watson.

At least 91 records · Page 5Linked to original sources
PubMed1994

The influence of continuous ambulatory peritoneal dialysis connection technique on peritonitis rate and technique survival.

Peritonitis is still the most common complication of continuous ambulatory peritoneal dialysis (CAPD). Several measures have been used to prevent peritonitis, including prophylactic antibiotics and a variety of connection techniques. This study was designed to evaluate the effects of different connection techniques, age at the start of CAPD, sex, and diabetic status on peritonitis rate and technique survival. Three hundred twenty-seven patients treated with CAPD and followed for 8,804.4 patient-months at the Vancouver General Hospital between February 13, 1978, and August 31, 1992, were reviewed. The mean age of the patients was 57.1 +/- 16.3 years. The overall peritonitis rate was 16.6 patient-months per episode. The overall technique survival was 79.6%, 60.2%, and 41.8%, at 1, 2, and 3 years, respectively. Patients using "standard" spike technique (group A, n = 87), Luer lock connector (group B, n = 77), and Luer lock with iodine instillation at the dialysis bag connection site (group C, n = 120) had peritonitis rates of 10.4, 14.7, and 33.3 patient-months per episode, respectively. The relative risk (RR) of peritonitis was 3.5 for group A (95% confidence interval, 2.1 to 4.5) and 2.6 for group B (95% confidence interval, 1.7 to 3.9) compared with group C. Patient age at the start of CAPD, sex, and diabetic status had no effect on the RR of peritonitis. None of the variables studied, except patient age, affected technique survival.(ABSTRACT TRUNCATED AT 250 WORDS)

Actuarial Analysis↗
PubMed1994

Lymphocyte responses to DR1/4 restricted peptides in rheumatoid arthritis.

OBJECTIVE: To determine whether analog and unrelated DR1/4 binding peptides alter DR1/4 restricted responses of peripheral blood lymphocytes (PBL) from patients with rheumatoid arthritis (RA). METHODS: PBL from 25 patients with RA and 12 healthy controls were cultured with DR1/4 restricted peptides of the influenza haemagglutinin, amino acids 307-319 (HA) and matrix proteins, amino acids 17-29 (IM). Responses were determined by 3H-thymidine uptake proliferation assays and limiting dilution analysis. Competitor peptides were analogs HA-R312 and HA-K313 differing from HA by one amino acid at the 312 or 313 position respectively or unrelated peptides which bind to DR1/4. RESULTS: The responses of eight patients with RA to the two stimulatory influenza peptides did not differ significantly from controls and this was confirmed by the frequency estimate of T cells in PBL which responded to HA (mean frequency: 1 in 9.0 x 10(4), n = 5, in DR1/4+ RA patients, 1 in 7.6 x 10(4), n = 5, in DR1/4+ healthy controls). DR1/4 binding analogs of the HA peptide inhibited HA specific peptide responses of PBL from patients with RA and controls. Inhibition was also detected with unrelated peptides which bind to DR1/4 but to which the individual did not respond. CONCLUSION: Similar responses to two DR1/4 restricted peptides were observed in patients with RA and controls. Both antigen analog- and unrelated peptide-major histocompatibility complexes (MHC) can result in the inhibition of antigen specific responses in multi-clonal human lymphocyte populations. However, an analog peptide may be stimulatory in some individuals. These results provide some initial data for the development of a rational approach to MHC-specific immunomodulation in rheumatoid arthritis.

Adult↗
PubMed1994

Behavioral management of specific pathogen-free rhesus macaques: group formation, reproduction, and parental competence.

Breeding colonies of specific pathogen-free (SPF) rhesus macaques were established to eradicate the transmission of Herpesvirus simiae and several retroviruses in this species. Strategies to attain this goal included the combination of large numbers of monkeys into groups, the establishment of small unimale groups, and a program using animals that were temporarily socially restricted. All methods required the establishment of new social groups from unfamiliar animals. In using these methods, we encountered important behavioral questions related to the group formation process, as well as reproductive and parental competence. Age and prior social experience were important determinants of social and parental success. New multimale-multifemale SPF group formations were successful initially and involved the least aggression during the first breeding season when young females and older males were used. Formation of unimale groups was successful, even when males and females were of similar ages. Breeding competence did not seem to be affected by any of the SPF colony management procedures, but animals with restricted early social experience exhibited impaired parental competence when compared with animals with more social experience. Males were more sensitive to the effects of early social restriction than females. A variety of behavioral obstacles will be encountered when attempting to establish an SPF breeding colony by forming groups by use of these methods. Skilled behavioral management is necessary to surmount these obstacles and to achieve satisfactory social integration, reproduction, and parenting.

Aging↗
PubMed1993

Twins, triplets, and cerebral palsy in births in Western Australia in the 1980s.

OBJECTIVES: To examine the rate of cerebral palsy in twins and triplets in births from 1980 to 1989 in Western Australia and to identify factors associated with increase in risk. DESIGN: Pluralities for all births in Western Australia were identified through the standardised midwives' notification system, and cases of cerebral palsy were identified from the Western Australian cerebral palsy register. MAIN OUTCOME MEASURES: Multiple births, cerebral palsy, excluding postneonatal cause. RESULTS: The prevalence of cerebral palsy in triplets, of 28 per 1000 survivors to 1 year (95% confidence interval 11 to 63) exceeded that in twins (7.3; 5.2 to 10) and singletons (1.6; 1.4 to 1.8). Although twins and triples were more likely than singletons to be low in birth weight, their risks of cerebral palsy if low in birth weight were similar. In contrast, in normal birthweight categories twins had a higher rate of cerebral palsy (4.2; 2.2 to 7.7) than singletons (1.1; 1.0 to 1.3). The prevalence of cerebral palsy was similar in twins of unlike sex pairs, all of whom are dizygotic, and in like sex pairs. A twin pair in which one member died in utero was at higher risk of cerebral palsy: 96 per 1000 twin pairs (36 to 218) compared with 12 (8.2 to 17) for twin pregnancies in which both survived. There was a similar but non-significant trend for death of one triplet to be associated with increased risk of cerebral palsy in the survivors of the set. CONCLUSION: Triplet pregnancies produced a child with cerebral palsy 47 times more often than singleton pregnancies did and twin pregnancies eight times more often. Eighty six per cent of cerebral palsy in multiple births was in twins. As multiple births are increasing mainly because of personal and medical decisions the increased risk of cerebral palsy in multiple births is of concern.

Birth Order↗
PubMed1993

The effect of captopril on the superior mesenteric artery and portal venous blood flow in normal man.

1. Measurements of superior mesenteric artery and portal venous blood flow were made non-invasively along with systemic and other regional (cardiac index, forearm and cutaneous blood flow) vascular responses to acute ingestion of the ACE inhibitor captopril (50 mg) or placebo (50 mg vitamin C), in 12 healthy subjects while supine and during head-up tilt. 2. After captopril, superior mesenteric artery and portal blood flow rose markedly with a reduction in superior mesenteric artery vascular resistance. Supine blood pressure was unchanged but cardiac index and forearm blood flow rose; during head-up tilt, blood pressure fell in some subjects. 3. There was a rise in levels of plasma renin activity and a fall in levels of plasma angiotensin II after captopril. After placebo, there were no significant changes in splanchnic blood flow, systemic or other regional responses and in biochemical measurements, while supine. 4. Our studies indicate that captopril is a potent dilator of the splanchnic vascular bed and suggest that this action may contribute to its therapeutic effects. The studies indicate a role for angiotensin II in the control of this large vascular bed although other agents (bradykinin, prostacyclin) may contribute.

Adult↗
PubMed1993

Spastic quadriplegia in Western Australia: a genetic epidemiological study. I: Case population and perinatal risk factors.

In a case-control study of all cerebral palsy cases with moderate and severe spastic quadriplegia born between 1976 and 1985, males comprised three-quarters of the cases and tended to have more severe motor impairment than females. The majority of cases had multiple and severe disabilities, and 27 per cent had died by the time of data collection. There was an excess of low-birthweight and preterm births compared with all live births in WA. An intrapartum cause was considered possible in 18 of the 74 children; however, half of these had evidence of compromise before labour.

Australia↗
PubMed1993

Normal range for transdiaphragmatic pressures during sniffs with catheter mounted transducers.

BACKGROUND: Transdiaphragmatic pressure (sniff PDI) during maximal sniffs is a useful clinical test of inspiratory muscle function. Although a normal range has been established for sniff PDI using air filled balloons, no comparable data are available for catheter mounted pressure transducers. METHODS: Using a single catheter with two pressure transducers 15 cm apart, oesophageal and gastric pressures were recorded in 50 normal volunteers (25 women), five of each sex from each decade between the third and seventh decades of life. Each subject performed 10 maximal sniffs at functional residual capacity. RESULTS: Mean (SD) sniff PDI was 149 (32) cm H2O in men and 127 (22) cm H2O in women. The lower limits of normal for sniff PDI (mean -1.96 x SD) after logarithmic transformation of the data were 95 and 78 cm H2O in men and women respectively. CONCLUSIONS: With this technique transdiaphragmatic pressure can be measured using a single catheter which can easily be cleaned and reused. The values for sniff PDI are similar to those recorded previously with air filled balloons, suggesting that the method of recording pressure does not significantly affect the values obtained.

Adult↗
PubMed1993

Facial reconstruction of a 3500-year-old Egyptian mummy using axial computed tomography.

Rebuilding faces from skulls presented for forensic identification or of historical importance has been carried out for many years using standardized methods. However, the reproduction of the face of a 3500-year-old mummy still enclosed in its cartonnage proved to be an unusual challenge. The face had to be rebuilt without opening the cartonnage to ensure preservation of the remains. Consequently, the method devised involved using the latest medical imaging technology to determine the shape of the skull.

Adult↗
PubMed1992

Growth hormone response to clonidine in central and peripheral primary autonomic failure.

Patients with primary autonomic failure may have either pure autonomic failure (PAF) or multiple system atrophy (MSA) in which there is additional neurological involvement. Distinction between PAF and MSA at an early stage is important because a wide range of complications is associated with MSA, which has a poor response to drug therapy and a less favourable prognosis. We have investigated the growth hormone (GH) releasing effects of clonidine in patients with PAF and MSA to see whether this hormonal response could serve as a neuroendocrine marker to distinguish between the groups. Age-matched normal subjects were studied as controls. Both groups of patients had severe postural hypotension due to primary sympathetic failure of presumed central origin in MSA and peripheral origin in PAF. After clonidine, plasma GH concentrations increased in controls and PAF, with no change in MSA. Changes in plasma glucose and insulin concentrations were similar in all groups. Clonidine, therefore, stimulates growth hormone release in PAF but not MSA and may serve as a neuroendocrine marker in differentiating patients with MSA and a central autonomic defect from those with PAF with a peripheral defect.

Adult↗
PubMed1992

Trends in perinatal mortality and cerebral palsy in Western Australia, 1967 to 1985.

OBJECTIVE: To analyse the trends in stillbirths, neonatal deaths, and cerebral palsy in all infants born in Western Australia from 1967 to 1985. To relate these trends to changes in perinatal care, particularly in relation to avoidance of intrapartum asphyxia in term infants and the increased survival of low birthweight infants. DESIGN: Descriptive epidemiological study calculating population rates for perinatal deaths and cerebral palsy according to year of birth and birth weight. SETTING: Western Australia. SUBJECTS: All infants born after 20 weeks' gestation or weighing at least 400 g (live and stillborn). MAIN OUTCOME MEASURES: Stillbirths, neonatal deaths (from perinatal death certificates), and cerebral palsy (from a population based register). RESULTS: Overall stillbirth rates fell from 12.1/1000 total births in 1967-70 to 8.1 in 1983-5. Early neonatal mortality fell from 13.0/1000 live births to 4.4 over the same period whereas total cerebral palsy rates remained at around 2-2.5/1000 live births. Death rates fell in all birth weight categories, particularly in low birthweight infants between 1975 and 1985, the period when birthweight data were available. In contrast, cerebral palsy rates in infants under 1500 g rose significantly over this period (from 12.1 in 1968 to 64.9 in 1985). The rise was seen in all spastic categories, including severely and multiply handicapped children. CONCLUSIONS: Large increases in the use of interventions aimed at reducing birth asphyxia and handicaps had not (by 1985) resulted in lower rates of cerebral palsy. This suggests that birth asphyxia is not a major cause. The increased survival of low birthweight infants has resulted in more cerebral palsy in this group, due either to postnatal complications of immaturity or prenatal damage to the fetal brain. These findings have implications for planning perinatal care and for litigation for putative obstetric malpractice in cerebral palsy cases.

Asphyxia Neonatorum↗
PubMed1992

Pulmonary function after spinal surgery for idiopathic scoliosis.

Respiratory function was assessed in 20 patients with idiopathic scoliosis undergoing spinal surgery (median age, 15 years; range, 11-34 years; median preoperative vital capacity, 67%; range, 28-109% predicted). Ten patients underwent anterior spinal surgery through a thoracotomy incision, seven of whom had posterior spinal surgery as a second-stage procedure. The other ten had posterior spinal surgery as their initial operation. Postoperatively, three patients had clinical evidence of respiratory complications. Daytime oxygen saturation was reduced throughout the first postoperative week, with no significant difference between anterior and posterior spinal surgery. Hypercapnia was unusual and generally mild. Vital capacity was reduced significantly 1 week after both anterior and posterior spinal surgery (P less than 0.05). The median vital capacity 1 week after anterior spinal surgery was 45% of preoperative values compared with 78% after posterior surgery (P less than 0.05). Inspiratory muscle strength, as assessed by sniff mouth pressure, was 56% of preoperative values 1 week after anterior spinal surgery (P less than 0.05) and 85% after posterior spinal surgery (not significant). Vital capacity, but not sniff mouth pressure, remained significantly reduced 6 weeks after surgery. Oxygen saturation should be monitored noninvasively during the first week after both anterior and posterior spinal surgery even in patients at low risk of developing respiratory complications.

Adolescent↗
PubMed1992

Respiratory disease in systemic lupus erythematosus: correlation with results of laboratory tests and histological appearance of muscle biopsy specimens.

BACKGROUND: In systemic lupus erythematosus, certain laboratory tests and evidence from muscle biopsy specimens of lymphocytic vasculitis reflect disease activity. A study was designed to determine if such indices predict respiratory lesions, and in particular whether the presence of vasculitis in quadriceps muscle reflects respiratory muscle function. METHODS: Twenty seven 27 patients with systemic lupus erythematosus were studied, ten of whom were consecutive untreated patients and 17 having clinically active disease and being treated. They were prospectively evaluated on the basis of erythrocyte sedimentation rate, lymphocyte count, C3 degradation products, quadriceps muscle biopsy, spirometry, lung volumes, carbon monoxide transfer factor, and mouth pressure during a maximal sniff. RESULTS: Lung function test results were abnormal in 12 patients. Vital capacity was reduced in seven, carbon monoxide transfer factor capacity in five, and mouth pressure was low (< 70% predicted) in ten. Lymphocytic vasculitis was seen in the muscle biopsy specimens of ten patients. No correlation was found between laboratory tests and lung function or mouth pressure, or between the presence of lymphocytic vasculitis and mouth pressure. In untreated patients, those with lymphocytic vasculitis had lower spirometric values. CONCLUSIONS: In systemic lupus erythematosus, evidence from muscle biopsy specimens of lymphocytic vasculitis is not predictive of impaired inspiratory muscle function as measured by mouth pressure. In untreated patients there were relationships between some laboratory test results and respiratory function, but this was not the case for the whole group. In systemic lupus erythematosus, laboratory tests and evidence from muscle biopsy specimens of lymphocytic vasculitis are therefore unlikely to be helpful in the assessment of respiratory disease.

Adult↗
PubMed1991

Social class, gay men and AIDS prevention.

The relationship between sexuality, gay communities and class is potentially a very large problem for AIDS prevention. Class is a historical process which interacts with sexuality in ways still little understood. The complexities of modern class structures need full acknowledgement; labour market groupings are internally divided, and cultural privilege and exclusion are important. A community survey in New South Wales of men who have sex with men shows the class selectiveness usual in such research. An exploration of correlates of labour market position, income and education finds few relationships with attachment to milieu except for involvement with gay organisations, and minor differences in broad measures of sexuality but some class differences in HIV risk-taking and some differences in exposure to information and in attitude. An exploration of several cases from a life-history study of working-class gay men shows the impact of class circumstance on the formation of sexual relationships and points to the accessibility of unlabelled homosexual activity in working-class milieux. Research on working-class education points to the importance of curriculum change in overcoming class exclusion, and is moving towards empowerment models of great relevance in AIDS education.

Acquired Immunodeficiency Syndrome↗
PubMed1991

Abnormalities of the seminal tract causing infertility: diagnosis with endorectal sonography.

Endorectal sonography, developed primarily for use in the diagnosis and staging of prostatic carcinoma, should be the first imaging technique used in the evaluation of an infertile man with low semen volume in whom either a hypoplastic or obstructed seminal tract is suspected. Endorectal sonography allows visualization of the seminal vesicles, which are otherwise difficult to examine. We used endorectal sonography to evaluate six young men, five of whom were being evaluated for azoospermia and infertility. One patient had no identifiable seminal vesicle on either side. Four patients had unilateral absence of the seminal vesicles. Of these four, three had a sonographically normal-appearing seminal vesicle on the contralateral side, and the fourth had an obstructed system contralaterally. The sixth patient had a hypoplastic system on the left and an obstructed system on the right. The delineation of an obstructed or agenetic seminal vesicle and seminal tract on endorectal sonography allows decisions to be made regarding treatment and prognosis.

Adult↗