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Biomedical subjects

C Roberts

Publications and source records attributed to C Roberts.

At least 37 records · Page 2Linked to original sources
PubMed1994

Current changes in smoking attitudes and behaviours among adolescents in Wales, 1986-1992.

This paper presents data on recent trends in adolescent smoking in Wales. The data are drawn from four large-scale surveys conducted across the Principality in 1986, 1988, 1990 and 1992. The results show that there has been some success in delaying early experimentation with smoking, as well as some improvement in the attitudes of smokers towards their habit. Against this, there has been little change in smoking prevalence amongst both boys and girls, and cigarettes remained widely available for purchase by the under-16s. The implications of these findings for further action on smoking and the young are discussed.

Adolescent↗
PubMed1994

Nasal airflow after septorhinoplasty.

The changes in nasal function which occur after septorhinoplasty for obstruction were investigated by anterior rhinomanometry in 15 subjects. Objective and subjective measures of outcome were compared. Anterior rhinomanometry was performed after nasal decongestion. These data were mathematically transformed to determine the amount of airflow asymmetry through the nostrils and the stiffness of the nasal valve. The results suggested that the presence of gross airflow asymmetry (> +/- 80%) in patients prior to surgery was a bad prognostic indicator for post-operative satisfaction with the airway. Patient satisfaction with function and cosmetic appearance post-operatively was correlated with the presence of symmetrical nasal airflow. Nasal valve stiffness did not seem to be affected by septorhinoplasty.

Adult↗
PubMed1994

Perceptions of denture aesthetics: a two-centre study of denture wearers and denture providers.

A study into perceptions of complete dentures was carried out in two dental schools, one in Australia and the other in England. Two-hundred participants were asked to assess photographs of five sets of dentures for age, gender and personality. Results were subjected to a multi-rater kappa statistic. Although no centre was determined to be better than the other, it was highly significant that Australian teachers were confident enough to state that they were unable to determine age or gender from the information supplied.

Adult↗
PubMed1994

Incisal overjet as an outcome measure in unilateral cleft lip and palate management.

The Goslon Yardstick is a clinical tool used to rank dental study casts of persons with cleft lip and palate in the late mixed or early permanent dentition into one of five categories. It has been successfully used to investigate the outcomes of the surgical treatment of these anomalies as well as the effects of these deformities on untreated individuals. In this study, 40 study casts ranked by the Goslon Yardstick were digitized using a reflex metrograph. The overjet, overbite, and incisal angulation, and the crossbites of the canines and molars were calculated for each of the sets of casts. Multiple regression analysis was used to determine the predictive value of these variables upon the Goslon scores. The overjet was found to explain 87% of the variance of the Goslon score (p < .0001). No other component had a significant predictive value. The range of overjet associated with the different Goslon scores was calculated from the regression equation. In conclusion, the advantages of using overjet as an indicator of outcome as an alternative to the Goslon Yardstick were discussed.

Child↗
PubMed1994

Dentofacial form in the five-year-old child with unilateral cleft lip and palate.

It is generally believed that studies of outcome for children with clefts of the lip and palate should be based on patients who are in their teens. This means that health care workers who look after these children would have to wait many years until the quality of treatment could be evaluated. In this study, significant differences between two centers, Oslo and Manchester, in facial form at the age of 5 years were detected. Based on cephalometric analysis, children from Manchester were more likely to have a retrognathic maxilla with the upper lip significantly behind the esthetic plane. An important future step may be the setting up of "reference centers" with a large archive of database information for each racial group. This would assist smaller centers in comparing their outcomes.

Age Factors↗
PubMed1994

Role function and mental health in postpartum working women: a pilot study.

1. Postpartum women have unique needs warranting study due to competing perspectives on the duration and time needed for recovery after childbirth. 2. This pilot study tests measures of role function and mental health in a sample of 26 women returning to work within 6 months of childbirth. 3. The study did not reveal decrements in mental health among subjects, but did reveal limitations to functional status. The results also suggested that the adapted measure of role function, and the measure of mental health, are reliable and have some preliminary evidence of construct validity in this population. 4. The results of the study have implications for occupational health nursing practice, including worker assessment and family policy development, and serve as a resource for measuring health outcomes in workers.

Female↗
PubMed1994

The accuracy of 'power' maps to display curvature data in corneal topography systems.

PURPOSE: To quantify the error introduced by videokeratographic corneal topography devices in using a paraxial formula to calculate power over the entire corneal surface, including areas removed from the central paraxial region where the formula is known to be invalid. METHODS: Corneal refractive power and two paraxial power approximations were computed as a function of distance from the apex for three theoretical surfaces, a sphere and two ellipsoids with 0.3 and 0.5 eccentricities. Color dioptric maps were then theoretically created. RESULTS: For the spherical surface, both curvature-based paraxial power approximations were uniform over the entire surface because curvature is constant. However, the corneal refractive power increased from center to periphery, demonstrating the known phenomenon of spherical aberration. For the ellipsoids, which have been shown to model the human cornea, curvature-based power approximations decreased from center to periphery because the curvature flattens peripherally. However, refractive power increased from center to periphery. The limits of the central paraxial region for these surfaces was shown to be approximately 2 mm in diameter for the paraxial power approximation used by videokeratographic devices to measure 8 mm in diameter. CONCLUSIONS: The direct correlation between corneal curvature and power with which clinicians are familiar is not valid in the peripheral regions measured by videokeratographic devices. Topographic devices measure curvature, which should not be interpreted as corneal power except in the central region. A recommendation to device manufacturers is to display "color curvature maps" instead of color dioptric maps, and to label the color bar with curvature values instead of power.

Cornea↗
PubMed1993

Determination of plasma membrane lipid mass and composition in cultured Chinese hamster ovary cells using high gradient magnetic affinity chromatography.

We have utilized wheat germ agglutinin conjugated to iron/dextran particles in conjunction with high gradient magnetic affinity chromatography (HIMAC) to prepare plasma membranes from cultured cells. Membrane-impermeable succinimidyl esters inactivate alkaline phosphodiesterase 1 (APDE-1) and were used to establish the proportion of APDE-1 expressed at the cell surface. The yield of inhibitable APDE-1 provides an accurate indication of plasma membrane yield, which was > 90% for Chinese hamster ovary (CHO) cells. Plasma membranes prepared by HIMAC contained < 5-13% of endoplasmic reticulum, Golgi, mitochondria, lysosomes, or endosomes. Pulse-chase experiments performed with the alpha 5 beta 1 integrin receptor confirmed the high yield of plasma membrane and demonstrated the utility of this procedure for examining trafficking of proteins to and from the plasma membrane. We determined the lipid content of plasma membranes prepared by HIMAC. CHO plasma membranes contain 49% of total cellular phospholipid, 69% of sphingomyelin, and 64% of cholesterol. Phosphatidylserine was the only glycerophospholipid highly enriched (71%) in the retained fraction. The glycosphingolipids lactosylceramide and ganglioside GM3 were enriched in the plasma membrane fraction to the same extent as sphingomyelin. The major fraction of the glycosphingolipid precursors glucosylceramide and ceramide was localized to intracellular membranes. These findings indicate that the plasma membrane of CHO cells contains approximately half of the total cellular phospholipids and an even higher percentage of sphingomyelin and cholesterol. The high efficiency and rapidity of this isolation procedure should aid the analysis of plasma membrane components significantly.

Animals↗
PubMed1993

Effects of nutritional counseling on lipoprotein levels in a pediatric lipid clinic.

OBJECTIVE: To determine the impact of nutritional counseling on lipoprotein profiles in dyslipoproteinemic children. DESIGN: Retrospective case review. SETTING: An academic hospital-based pediatric lipid clinic in Boston, Mass. PARTICIPANTS: One hundred four newly referred children with primary dyslipoproteinemia. INTERVENTIONS: Nutritional recommendations were adapted from the National Cholesterol Education Program's step 2 diet. Three-day diet records were used to assess baseline and follow-up diets. RESULTS: Two thirds of the children continued to have excellent diets or improved their diets after counseling, but low-density lipoprotein cholesterol (LDL-c) values decreased by 15% or more in only 19% of children. The observed change in LDL-c was not significantly associated with nutritional counseling. However, a strong correlation was evident between dietary interventions and concentration of high-density lipoprotein cholesterol (HDL-c) values in serum. Marked fat restriction lowered HDL-c levels, while liberalization of use of fat, with emphasis on monounsaturates, in a subset of children following an excessively fat-restricted diet on presentation, appeared to improve HDL-c levels. CONCLUSIONS: After nutritional counseling, LDL-c levels decreased by 15% or more in only 19% of dyslipoproteinemic children referred for treatment. There were no clear predictors of LDL-c responsiveness, but changes in dietary fat intake appeared to significantly influence HDL-c levels.

Child↗
PubMed1993

Stability of red cell antigens and plasma coagulation factors stored in a non-diethylhexyl phthalate-plasticized container.

Red cell antigen stability studies were performed to evaluate whether the storage of red cells in plastic segments made up of a new non-di-2(ethylhexyl)phthalate (DEHP)-plasticized material resulted in poststorage antigenic reactivity different from that seen in segments made from DEHP-containing plastic. Serial 1-in-2 dilutions of commercially available antisera were prepared and tested by using stored red cells obtained from segments on Days 0, 28, 42, and, in some instances, 49. Antigenic determinants tested included A, B, D, c, K, Le(a), Fya, Jka, M, and P1. To minimize variability, the same reagent lots were used throughout each study, and the same technologists performed the assays in each laboratory. No significant differences in titration scores were seen when cells stored in segments made of the test plastic were compared with cells obtained from the same donor and stored for the same length of time in segments made of control plastic. In addition, plasma coagulation factor stability was studied in fresh-frozen plasma and cryoprecipitate stored for up to 1 year in the non-DEHP-plasticized plastic containers. No significant differences were seen in prothrombin time, activated partial thromboplastin time, fibrinogen content, or factor V, VII, VIII, IX, or X activity as compared with plasma stored for equal periods of time in control plastic containers. It is concluded that the test plastic does not adversely affect red cell antigenic reactivity or plasma coagulation factor stability and that it is suitable for use in clinical transfusion practice.

Blood Coagulation Factors↗
PubMed1993

Platelet activating factor (PAF) enhances mitosis in preimplantation mouse embryos.

Preimplantation mouse embryos were used to determine whether the reported significant increase in embryo metabolism and viability achieved through supplementation of the culture medium with the ether phospholipid 1-o-alkyl-2-acetyl-sn-glycero-3-phosphocoline (platelet activating factor, PAF) is attributable to an enhanced rate of mitosis. Blastocyst-stage embryos cultured in the presence of 0.186 to 18.6 microM exogenous PAF had a significantly (P < 0.01) higher mitotic index (the proportion of cells arrested in metaphase following incubation in colchicine) than those cultured without PAF. At the 8-cell stage, 29% more blastomeres were in metaphase in the PAF-treated group (P < 0.01) 8 h after the addition of colchicine, but by 16 h there was no difference between groups; thus, PAF increased the rate at which cells entered metaphase but did not increase the total number. The mitotic index showed a negative correlation with the number of cells within blastocysts. PAF had a significantly (P < 0.01) greater impact on the mitotic index of blastocysts with fewer cells. The action of PAF was specific, being completely blocked by the PAF-receptor antagonist WEB 2086 (33 microM). In the absence of exogenous PAF the mitotic index was lower with WEB 2086 than without, suggesting inhibition of the action of endogenous embryo-derived PAF. These results show that PAF stimulates the rates at which cells within the preimplantation mouse embryo enter metaphase in vitro and suggest that it would decrease their doubling time, perhaps accounting for the embryotrophic actions of PAF.

Animals↗
PubMed1993

Isolation of a gene expressed during early embryogenesis from the region of 22q11 commonly deleted in DiGeorge syndrome.

DiGeorge syndrome (DGS) is one of several syndromes associated with deletions within the proximal long-arm of chromosome 22. The region of chromosome 22q11 responsible for the haploinsufficiency syndromes (the DiGeorge Critical Region or DGCR) has been mapped using RFLPs, quantitative Southern blotting and FISH. Similar deletions are seen in the velo-cardio-facial syndrome (VCFS) and familial congenital heart defects. It is not known whether the phenotypic spectrum is the result of the hemizygosity of one gene or whether it is a consequence of contiguous genes being deleted. However, the majority of patients have a large (> = 2Mb deletion). In this paper we report the isolation of a gene, lab name T10, encoding a serine/threonine rich protein of unknown function which maps to the commonly deleted region of chromosome 22q11. Studies in the mouse indicate that it maps to MMU16 and is expressed during early embryogenesis. Although not mapping within the shortest region of overlap for DGS/VCFS, and therefore not the major gene involved in DGS, the expression pattern suggests that this gene may be involved in modifying the haploinsufficient phenotype of hemizygous patients.

Amino Acid Sequence↗
PubMed1993

Isolation of a putative transcriptional regulator from the region of 22q11 deleted in DiGeorge syndrome, Shprintzen syndrome and familial congenital heart disease.

A wide spectrum of birth defects are caused by deletions of the DiGeorge syndrome critical region (DGCR) at human chromosome 22q11. Over one hundred such deletions have now been examined and a minimally deleted region of 300kb defined. Within these sequences we have identified a gene expressed during human and murine embryogenesis. The gene, named TUPLE1, and its murine homologue, encodes a protein containing repeated motifs similar to the WD40 domains found in the beta-transducin/enhancer of split (TLE) family. The TUPLE1 product has several features typical of transcriptional control proteins and in particular has homology with the yeast Tup1 transcriptional regulator. We propose that haploinsufficiency for TUPLE1 is at least partly responsible for DiGeorge syndrome and related abnormalities.

Abnormalities, Multiple↗
PubMed1993

Low birth-weight in NSW, 1987: a population-based study.

The New South Wales perinatal data collection was used to examine the association between low birth-weight and some of its potential risk factors. The study population comprised all recorded singleton births to residents of NSW in 1987. Low birth-weight infants were categorized as either small for gestational age (SGA) or preterm (less than 37 weeks). Risk factors were analyzed separately for these categories. The risk factors examined were primarily demographic or reproductive history variables. Univariate analysis and multivariate logistic regression were used to evaluate the risk factors. The factors associated with SGA birth were mainly demographic (maternal age, parity, marital status, socioeconomic status, and ethnic group) while those associated with preterm birth had more reproductive history variables (maternal age, parity, marital status, prior spontaneous abortion, prior induced abortion, prior stillbirth or neonatal death, sex of infant). A first antenatal visit after 12 weeks had a statistically significant but small effect on both SGA and preterm birth.

Abortion, Spontaneous↗
PubMed1993

Isolation of a new marker and conserved sequences close to the DiGeorge syndrome marker HP500 (D22S134).

End fragment cloning from a YAC at the D22S134 locus allowed the isolation of a new probe HD7k. This marker detects hemizygosity in two patients previously shown to be dizygous for D22S134. This positions the distal deletion breakpoint in these patients to the sequences within the YAC, and confirms that HD7k is proximal to D22S134. In a search for coding sequences within the region commonly deleted in DGS we have identified a conserved sequence at D22S134. Although no cDNAs have yet been isolated, genomic sequencing shows a short open reading frame with weak similarity to collagen proteins.

Amino Acid Sequence↗