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Biomedical subjects

R J Gardner

Publications and source records attributed to R J Gardner.

At least 73 records · Page 4Linked to original sources
PubMed1991

Development of pragmatic exposure-control concentrations based on packaging regulation risk phrases.

This paper relates United Kingdom and other national Occupational Exposure Limits (OELs) for volatile organic substances to the Risk Phrases (RPs) which they are assigned under EEC Classification, Packaging and Labelling Directives. The OELs for organic volatiles assigned RP 20 ('harmful by inhalation'), RP 23 ('toxic by inhalation') and RP 26 ('very toxic by inhalation') fitted better to the cumulative log-normal distribution than to the cumulative normal distribution and the means for RPs 23 and 26 were not significantly different. The means for RP 20 and RP 23/26 were 100 mg m-3 (or 25 ppm) and 5 mg m-3 (or 1 ppm), respectively. In the absence of any relevant, specific information, it is suggested that these values may be useful as guidelines for pragmatic exposure-control concentrations (PECCs) for the control of exposure by inhalation in workplaces handling substances labelled with these RPs.

Environmental Exposure↗
PubMed1991

Inhalation anaesthetics--exposure and control during veterinary surgery.

Results are reported for air sampling surveys carried out by the Health and Safety Executive (HSE) in 14 veterinary surgeries. For all personnel the geometric mean (GM) time-weighted average (TWA) exposures to halothane and nitrous oxide over the working period were 2.6 ppm (range: less than 0.5 119 ppm) and 100 ppm (range: 14-1700 ppm), respectively. Since surgery rarely lasted for more than 4 h the corresponding GMs for 8-h TWAs were lower, being 1.3 ppm (range: less than 0.5-34 ppm) for halothane and 34 ppm (range: 5-530 ppm) for nitrous oxide. The GM exposures of veterinarians and nurses were very similar. The size of the practice and the use of scavenging were significant factors in determining personal exposures to inhalation anaesthetics: by comparison general ventilation had little effect. The results are compared with earlier data from human surgery, and previous studies of exposure to inhalation anaesthetics during veterinary surgery are briefly reviewed.

Anesthesia, Inhalation↗
PubMed1991

The phenotype in placental trisomy 7.

Trisomy 7, in mosaic state, was identified at chorionic villus sampling. The pregnancy was closely followed, and proceeded uneventfully. Mosaic trisomy 7 was confirmed in the term placenta, the organ having no structural abnormalities; the karyotype of the phenotypically normal baby was 46,XY. Trisomy 7, mosaic or nonmosaic, detected at chorionic villus sampling in an ultrasonographically normal pregnancy, appears typically to be associated with a normal fetal karyotype, and placental growth, structure, and function are not discernibly compromised.

Adult↗
PubMed1991

Linkage studies in tuberous sclerosis. Chromosome 9?, 11?, or maybe 14!

Published reports show linkage of tuberous sclerosis (TSC) to either chromosome 9 in some families or chromosome 11 in other families. We studied 243 individuals (82 with TSC) from 16 multigenerational TSC families. The diagnosis of TSC conformed to the criteria of Gomez. Penetrance was estimated at 0.90. DNA markers were analyzed using Southern blotting, probe hybridization, autoradiography, and genetic linkage analysis. Two-point lod scores for TSC were calculated for 43 genetic markers distributed over 11 chromosomes. Tests for homogeneity rejected the null hypothesis of homogeneity. Linkage to TSC was excluded (z less than or equal to -2, theta greater than or equal to 0.05) for 23 of these markers including 9q34 and 11q markers. One family gave z(theta max) = 1.8, theta max = 0.001 with ABO (on 9q34), and two other families attained lod scores greater than 1 for 9q34-region markers. The lod score for TSC versus chromosome 14 marker pAW101 (D14S1) was z(theta max) = 1.98, theta max = 0.15. A single large family has overall negative lod scores for markers localized to both chromosome 9 and chromosome 11. These data confirm genetic heterogeneity in TSC and suggest linkage of some families to 9q34. Furthermore, the data suggest that 14q may be an interesting area.

Chromosome Mapping↗
PubMed1990

Early prenatal diagnosis of genetic abnormality by chorion villus sampling.

We describe a series of 100 cases of prenatal genetic diagnosis using the technique of chorion villus sampling. The advantage of chorion villus sampling in terms of earlier diagnosis, and its disadvantage of a higher incidence of false results, compared with amniocentesis, are noted. The comparative risks for pregnancy loss are discussed.

Abortion, Spontaneous↗
PubMed1990

A DNA diagnostic service.

We describe the use of techniques of DNA analysis for the diagnosis of certain inherited diseases during life and in the prenatal period, and for the diagnosis of some infectious diseases. Most local and some national needs for predictive genetic testing have been met. The costs of establishing our service are presented and are compared with those of similar services recently established in the United Kingdom. In the 12 month period described, running costs were approximately $57,000 and salaries for the two scientific officers and the medical technologist required to run the service were $97,000. The prerequisites for the successful running of such a service are discussed.

Costs and Cost Analysis↗
PubMed1990

Syndrome of a craniofacial dysostosis, limb malformation, and omphalocele.

We describe an infant with a unique combination of a severe craniofacial dysostosis and a very distinctive facies, severe limb defects, a thoracic deformity, and an omphalocele as the major anomalies. We propose that this represents a "new" syndrome of multiple congenital abnormalities.

Abnormalities, Multiple↗
PubMed1990

Linkage of an autosomal dominant clefting syndrome (Van der Woude) to loci on chromosome Iq.

Van der Woude syndrome (VWS) is an autosomal dominant disorder in which affected individuals have one or more of the following manifestations: cleft lip, cleft palate, hypodontia, or paramedian lower-lip pits. VWS is a well-characterized example of a single-gene abnormality that disturbs normal craniofacial morphogenesis. As a first step in identifying genes involved in human development, we used a candidate-gene-and-region approach to look for a linkage to VWS. Six families with 3 or more generations of affected individuals were studied. Evidence for linkage (theta = 0.02, lod score = 9.09) was found between the renin (REN) gene on 1q and VWS. Other linked loci included CR1, D1S58, and D1S53. The genes for laminin B2 (LAMB2), a basement-membrane protein, and for decay-accelerating factor (DAF) were studied as possible candidate genes on 1q. Recombinants between VWS and both LAMB2 and DAF excluded these genes from a causal role in the etiology of VWS for the families studied in this report. Multipoint linkage analysis indicated that the VWS locus was flanked by REN and D1S65 at a lod score of 10.83. This tight linkage with renin and other nearby loci provides a first step in identifying the molecular abnormality underlying this disturbance of human development.

Chromosomes, Human, Pair 1↗
PubMed1989

Trisomy 16 detected at chorion villus sampling.

Trisomy 16 detected at chorion villus sampling (CVS) may reflect the placental but not the fetal karyotype. We describe a case in which the pregnancy continued until intrauterine death at 37 weeks. Cytogenetic study of two placental samples showed 47, + 16 and 46,XX; the fetus was morphologically grossly normal, but fetal tissue culture was unsuccessful. Conservative management may be appropriate when trisomy 16 is detected at CVS and the pregnancy is normal ultrasonographically.

Adult↗
PubMed1989

Absence of linkage of ABO blood group locus to familial tuberous sclerosis.

A mutation leading to tuberous sclerosis was linked to the ABO blood group locus (9q34) on the long arm of chromosome 9. In an effort to confirm this assignment, nine multigenerational families with tuberous sclerosis, comprising 126 sampled individuals, were assessed for linkage of the ABO locus to tuberous sclerosis. Two-point linkage analysis and multilocus linkage analysis were used to evaluate linkage between tuberous sclerosis and the markers ABO, MCT136, and AblK2. Linkage of ABO to tuberous sclerosis was excluded for a distance of 20 centimorgans (cM) encompassing the region of the ABO locus. There was no evidence for genetic heterogeneity within this data set. Using 23 polymorphic markers, exclusion mapping demonstrated only a 1% probability that the tuberous sclerosis locus was on the distal short arm of chromosome 9 and provided no evidence in support of a tuberous sclerosis locus on the remainder of chromosome 9 including the area of the ABO locus.

ABO Blood-Group System↗
PubMed1989

Inhalation anaesthetics--exposure and control: a statistical comparison of personal exposures in operating theatres with and without anaesthetic gas scavenging.

Results are reported for air sampling surveys undertaken by the Health and Safety Executive (HSE) from 1980 to 1984 using diffusive samplers in 40 operating theatres and 18 recovery areas at 27 hospitals. For all personnel the geometric mean time-weighted average exposure to nitrous oxide in unscavenged theatres was 94 ppm and in scavenged theatres 32 ppm; the corresponding means for halothane were 1.7 and 0.7 ppm, respectively. Intermittent use of scavenging led to mean exposures between those found in scavenged and unscavenged conditions. Anaesthetists showed higher mean exposures than other staff in all conditions. Statistical analysis of the data demonstrates that mean exposures of operating theatre staff were significantly lower in scavenged than in unscavenged theatres. For most staff, exposure was also significantly lower in theatres using active scavenging systems compared with those using passive systems. The literature on the hazards of chronic exposure to inhalation anaesthetics and previous studies of exposure is also briefly reviewed.

Air Pollutants↗
PubMed1989

Prevalence of von Recklinghausen neurofibromatosis in Dunedin, New Zealand.

A point prevalence study of von Recklinghausen neurofibromatosis (NF-1) was undertaken in greater Dunedin, New Zealand, having a base population of 113,700. A total of 52 individuals with NF-1 were identified, for a crude prevalence estimate of 45.7 per 100,000 (95% confidence interval 31.6-59.8 per 100,000) or 1 in 2,190 and an age-standardized prevalence of 48.5 per 100,000 (95% confidence interval 34.7-62.4 per 100,000) or 1 in 2,062. This is the highest prevalence estimate reported to date. This is presumed most likely to be due to a small population effect. The prevalence of NF correlated with age, being greatest among those aged 20-29 years and relatively low among those 60 or more years of age.

Humans↗
PubMed1988

Familial ectopic ossification.

We report a family with dominantly inherited ectopic ossification. It is characterised by childhood onset of multifocal subcutaneous ossifications (primary osteoma cutis), which are of trivial clinical significance. One family member had extensive ectopic ossification involving one limb. We speculate that this may reflect somatic mutation having caused conversion to homozygosity.

Bone and Bones↗