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Biomedical subjects

A Robertson

Publications and source records attributed to A Robertson.

At least 55 records · Page 3Linked to original sources
PubMed2001

Knowledge-based system for structured examination, diagnosis and therapy in treatment of traumatised teeth.

Dental trauma in children and adolescents is a common problem, and the prevalence of these injuries has increased in the last 10-20 years. A dental injury should always be considered an emergency and, thus, be treated immediately to relieve pain, facilitate reduction of displaced teeth, reconstruct lost hard tissue, and improve prognosis. Rational therapy depends upon a correct diagnosis, which can be achieved with the aid of various examination techniques. It must be understood that an incomplete examination can lead to inaccurate diagnosis and less successful treatment. Good knowledge of traumatology and models of treatments can also reduce stress and anxiety for both the patient and the dental team. Knowledge-based Systems (KBS) are a practical implementation of Artificial Intelligence. In complex domains which humans find difficult to understand, KBS can assist in making decisions and can also add knowledge. The aim of this paper is to describe the structure of a knowledge-based system for structured examination, diagnosis and therapy for traumatised primary and permanent teeth. A commercially available program was used as developmental tool for the programming (XpertRule, Attar, London, UK). The paper presents a model for a computerised decision support system for traumatology.

Adolescent↗
PubMed2001

Macronutrient and food intake in the Baltic republics.

OBJECTIVE: The objective of this study was to describe mean macronutrient and food intakes in the Baltic republics, with a particular focus on fat, vegetable and fruit consumption. DESIGN: Cross-sectional study. SETTING: Data from surveys conducted in Estonia, Latvia and Lithuania in the summer of 1997 were used. Information was collected using a 24 h recall of dietary intake and an interviewer-administered questionnaire. SUBJECTS: Representative national samples of adults were selected. All those with information from the dietary recall were included in the study (Estonia: n = 2015; Latvia: n = 2300; Lithuania: n = 2094). RESULTS: The mean proportion of energy from fat was high in each country, but particularly in Lithuania (44%) and Latvia (42%) compared with Estonia (36%). In contrast, percentage energy from carbohydrate, protein and alcohol was higher in Estonia. Mean protein intake was generally sufficient if not high in some population sub-groups. Median vegetable intakes were very low (<200 g/day) in each country, particularly in Latvia. While 78% of the Lithuanian respondents consumed vegetables daily, this was the case in only 60% of the Latvian and 48% of the Estonian respondents. CONCLUSIONS: This study suggests that there is a pressing need to replace high-fat energy dense foods by foods rich in complex carbohydrates and dietary fibre, such as vegetables and fruits, in the Baltic republics. This could provide the populations with a reduced risk and increased protection against non-communicable diseases. These issues will need to be tackled through comprehensive food and nutrition policies and health promotion campaigns.

Adult↗
PubMed2001

Transmission loss of sound into incubators: implications for voice perception by infants.

OBJECTIVE: To assess the transmission of sound into incubators as a function of talker position (i.e., standing or sitting), incubator port position (i.e., opened or closed), and center frequency (i.e., 125 to 10,000 Hz in one-third octave steps). The second objective was to estimate the audibility of the human voice inside the incubator. STUDY DESIGN: L(eq) measures of signal transmission loss and motor noise were obtained from two incubators. RESULTS: In general, signal transmission loss was greater for the standing-talker position, with front portholes closed, and for high-frequency spectra. Motor noise was greater with both front portholes closed and for lower-frequency spectra. The greatest signal delivery to an infant would be obtained when the speaker is sitting using a raised vocal effort while the incubator ports are opened. CONCLUSION: Measured signal transmission loss and motor noise characteristics of two incubators suggest that only mid-frequency speech spectra would be audible to infants and only at a speech-to-noise ratio of approximately 5 to 10 dB with a raised vocal effort.

Acoustics↗
PubMed2001

Idiopathic gonadotrophin deficiency: genetic questions addressed through phenotypic characterization.

OBJECTIVE: The association of idiopathic hypogonadotrophic hypogonadism (IHH) with congenital olfactory deficit defines Kallmann's syndrome (KS). Although a small proportion of IHH patients have been found to harbour defined genetic lesions, the genetic basis of most IHH cases remains to be elucidated. Genes currently recognized to be involved comprise KAL (associated with X-linked-KS), the GnRH receptor (associated with resistance to GnRH therapy), DAX 1 (associated with adrenohypoplasia congenita) and three loci also associated with obesity, leptin (OB), leptin receptor (DB) and prohormone convertase (PC1). Because of the rarity of the condition and the observation that patients are almost universally infertile without assistance, familial transmission of IHH is encountered infrequently and pedigrees tend to be small. This has constrained the ability of conventional linkage studies to identify other candidate loci for genetic IHH. We hypothesized that a systematic clinical evaluation of a large patient sample might provide new insights into the genetics of this rare disorder. Specifically, we wished to examine the following propositions. First, whether normosmic (nIHH) and anosmic (KS) forms of IHH were likely to be genetically discrete entities, on the basis of quantitative olfactory testing, analysis of autosomal pedigrees and the prevalence of developmental defects such as cryptorchidism and cleft palate. Second, whether mirror movements and/or unilateral renal agenesis were specific phenotypic markers for X-linked-KS. DESIGN AND PATIENTS: We conducted a clinical study of 170 male and 45 female IHH patients attending the endocrinology departments of three London University teaching hospitals. Approximately 80% of data were obtained from case records and 20% collected prospectively. Parameters assessed included olfaction, testicular volume, family history of hypogonadism, anosmia or pubertal delay, and history or presence of testicular maldescent, neurological, renal or craniofacial anomalies. Where possible, the clinical information was correlated with published data on genetic analysis of the KAL locus. RESULTS: Olfactory acuity was bimodally distributed with no evidence for a spectrum of olfactory deficit. Testicular volume, a marker of integrated gonadotrophin secretion, did not differ significantly between anosmic and normosmic patients, at 2.0 ml and 2.2 ml, respectively. Nevertheless, the prevalence of cryptorchidism was nearly three times greater in anosmic (70.3%, of which 75.0% bilateral) than in normosmic (23.2%, of which 43.8% bilateral) patients. Individuals with nIHH, eugonadal isolated anosmia and/or KS were observed to coexist within 6/13 autosomal IHH pedigrees. On three occasions, fertility treatment given to an IHH patient had resulted in the condition being transmitted to the resulting offspring. Mirror movements and unilateral renal agenesis were observed in 24/98 and 9/87 IHH patients, respectively, all of whom were identifiable as X-KS males on the basis of pedigree analysis and/or defective KAL coding sequence. Abnormalities of eye movement and unilateral sensorineural deafness were observed in 10/21 and 6/111 KS patients, respectively, but not in nIHH patients. DISCUSSION: Patients with IHH are almost invariably either anosmic (KS) or normosmic (nIHH), rather than exhibiting intermediate degrees of olfactory deficit. Moreover, the prevalence of cryptorchidism is nearly three times greater in KS than in nIHH despite comparable testicular volumes, suggesting a primary defect of testicular descent in KS independent of gonadotrophin deficiency. Disorders of eye movement and hearing appear only to occur in association with KS. Taken together, these findings indicate a clear phenotypic separation between KS and nIHH. However, pedigree studies suggest that autosomal KS is an heterogeneous condition, with incomplete phenotypic penetrance within pedigrees, and that some cases of autosomal KS, nIHH and even isolated anosmia are likely to have a common genetic basis. The prevalences of anosmia, mirror movements and unilateral renal agenesis among X-KS men are estimated to be 100, 85 and 31%, respectively. In sporadic IHH, mirror movements and unilateral renal agenesis are 100% specific phenotypic markers of de novo X-KS. By comparison, only 7/10 X-KS families harboured KAL coding defects. Clinical ascertainment, using mirror movements, renal agenesis and ichthyosis as X-KS-specific phenotypic markers, suggested that de novo X-KS was unlikely to comprise more than 11% of sporadic cases. The majority of sporadic KS cases are therefore presumed to have an autosomal basis and, hence, the preponderance of affected KS males over females remains unexplained, though reduced penetrance in women would be a possibility.

Adolescent↗
PubMed2001

Dietary beliefs in the Baltic republics.

OBJECTIVES: As beliefs and knowledge about the possible effects of foods on health can influence food behaviours, this study examined selected dietary beliefs in the Baltic countries and the association of beliefs related to salt intake and to types of fat with food behaviours. DESIGN: A cross-sectional study. SETTING: Data from three surveys conducted in Estonia, Latvia and Lithuania in the summer of 1997 were used to describe the prevalence of dietary beliefs in these countries and to investigate the association between beliefs and behaviours (using logistic regression). SUBJECTS: Representative national samples of adults were selected in each country (Estonia, n = 2018; Latvia, n = 2308; Lithuania, n = 2153). RESULTS: Misunderstood concepts (myths) related to dietary salt, types of fat, meat consumption and bread and potatoes were observed in high proportions of the population. Education level was an important correlate of beliefs related to salt intake and types of fat, people with a higher education level being more likely to be familiar with these issues. Correct beliefs were not consistently associated with healthier behaviours (e.g. less frequent use of salt at the table and use of non-animal fats for cooking), except for salt intake in Estonia. CONCLUSIONS: Several misunderstood dietary concepts (myths) are still prevalent in the Baltic countries. Correct beliefs related to salt intake and types of fat were not consistent predictors of healthier food behaviours. In-depth qualitative investigations are needed to better describe and understand dietary beliefs and attitudes in the Baltic countries, and to identify barriers to the adoption of healthy food habits.

Adolescent↗
PubMed2001

The potential contribution of increased vegetable and fruit consumption to health gain in the European Union.

BACKGROUND: The risk of many important diseases can be reduced by consuming a diet rich in vegetables and fruit. For this reason the World Health Organization (WHO) recommends a daily intake of more than 400 g person(-1). The pattern of both the supply and intake of vegetables and fruit and the potential health gain achieved by increasing intake in the European Union (EU) and three accession countries are presented in this paper. METHODS: Patterns of supply and dietary intake were assessed using (1) FAO food balance sheets, which allow comparison between the levels of supply in countries but do not reflect actual intake; and (2) survey data reflecting dietary intake. Using WHO mortality data for coronary heart and cerebrovascular disease and major cancers up to age 65 years, the number of preventable deaths is estimated, assuming vegetable and fruit consumption were levelled up to that of the highest consuming group, and assuming relative risks of 0.5, 0.7 or 0.9. RESULTS: Vegetable and fruit consumption varies considerably between EU Member States. The populations of about half (seven) of the EU Member States have a mean daily intake of less than 275 g. Using the best current estimates of relative risk, over 26,000 deaths before the age of 65 years would be prevented annually in the EU if intake was levelled up to the highest consumption levels (and about double this number of deaths before the age of 75 years). CONCLUSION: Increasing the intake of vegetables and fruit is feasible and could result in considerable improvements in public health within the EU. Priority should be given to developing methods that demonstrate the burden of disease caused by too low intakes of vegetables and fruit. This would enable the appropriate social, cultural and economic policies to be developed within the EU.

Aged↗
PubMed2001

Social inequalities and the burden of food-related ill-health.

Increased health inequalities are a result of poverty and social inequalities. Examples of how food intake is affected by poverty exist throughout the European Region. The diets of low-income groups are likely to be inadequate. Low-income groups and specific groups such as children, adolescents, pregnant and lactating women, and older people often face problems gaining access to a healthy variety of safe foods. Safe healthy food may not be accessible to those most in need. Yet access to a safe and varied healthy diet is a fundamental human right and policies are needed to address this.

Adolescent↗
PubMed2001

Multicystic dysplastic kidney and Kallmann's syndrome: a new association?

BACKGROUND: Kallmann's syndrome is characterized by anosmia and hypogonadotrophic hypogonadism. Radiographic studies of teenagers and older subjects with the X-linked form of the syndrome have shown that up to 40% have an absent kidney unilaterally. Although this has been attributed to renal "agenesis", a condition in which the kidney fails to form, little is known about the appearance of the developing urinary tract either pre- or post-natally in individuals with Kallmann's syndrome. METHODS: We describe two brothers who had features of Kallmann's syndrome, most probably of the X-linked variety, who both had a major urinary-tract malformation detected before birth. RESULTS: The brothers were found to have unilateral multicystic dysplastic kidneys on routine antenatal ultrasound scanning and both underwent surgical nephrectomy of these organs post-natally. Immunohistochemical studies on the younger sibling revealed hyperproliferative dysplastic kidney tubules which overexpressed PAX2, a potentially oncogenic transcription factor, and BCL2, a cell-survival factor, surrounded by metaplastic, alpha smooth-muscle actin-positive stroma: similar patterns have been observed in patients with non-syndromic multicystic dysplastic kidneys. CONCLUSIONS: Our results describe a new type of urinary-tract malformation associated with Kallmann's syndrome. However, since multicystic kidneys tend to involute, only when more Kallmann's syndrome patients are screened in utero or in early childhood using structural renal scans, will it be possible to establish whether multicystic kidney disease is a bona-fide part of the syndrome.

Child, Preschool↗
PubMed2000

Domain specific interaction in the XRCC1-DNA polymerase beta complex.

XRCC1 (X-ray cross-complementing group 1) is a DNA repair protein that forms complexes with DNA polymerase beta (beta-Pol), DNA ligase III and poly-ADP-ribose polymerase in the repair of DNA single strand breaks. The domains in XRCC1 have been determined, and characterization of the domain-domain interaction in the XRCC1-beta-Pol complex has provided information on the specificity and mechanism of binding. The domain structure of XRCC1, determined using limited proteolysis, was found to include an N-terminal domain (NTD), a central BRCT-I (breast cancer susceptibility protein-1) domain and a C-terminal BRCT-II domain. The BRCT-I-linker-BRCT-II C-terminal fragment and the linker-BRCT-II C-terminal fragment were relatively stable to proteolysis suggestive of a non-random conformation of the linker. A predicted inner domain was found not to be stable to proteolysis. Using cross-linking experiments, XRCC1 was found to bind intact beta-Pol and the beta-Pol 31 kDa domain. The XRCC1-NTD(1-183)(residues 1-183) was found to bind beta-Pol, the beta-Pol 31 kDa domain and the beta-Pol C-terminal palm-thumb (residues 140-335), and the interaction was further localized to XRCC1-NTD(1-157)(residues 1-157). The XRCC1-NTD(1-183)-beta-Pol 31 kDa domain complex was stable at high salt (1 M NaCl) indicative of a hydrophobic contribution. Using a yeast two-hybrid screen, polypeptides expressed from two XRCC1 constructs, which included residues 36-355 and residues 1-159, were found to interact with beta-Pol, the beta-Pol 31 kDa domain, and the beta-Pol C-terminal thumb-only domain polypeptides expressed from the respective beta-Pol constructs. Neither the XRCC1-NTD(1-159), nor the XRCC1(36-355)polypeptide was found to interact with a beta-Pol thumbless polypeptide. A third XRCC1 polypeptide (residues 75-212) showed no interaction with beta-Pol. In quantitative gel filtration and analytical ultracentrifugation experiments, the XRCC1-NTD(1-183)was found to bind beta-Pol and its 31 kDa domain in a 1:1 complex with high affinity (K(d) of 0.4-2.4 microM). The combined results indicate a thumb-domain specific 1:1 interaction between the XRCC1-NTD(1-159)and beta-Pol that is of an affinity comparable to other binding interactions involving beta-Pol.

Amino Acid Sequence↗
PubMed2000

Physical inactivity in the Baltic countries.

BACKGROUND: Physical inactivity is a known risk factor for heart disease and obesity, two major health problems in the Baltic Republics. This study examined patterns of physical activity level in these countries, and correlates of leisure-time sedentary behavior. METHODS: Data from three national surveys of adults conducted in Estonia, Latvia, and Lithuania in 1997 were used. Respondents who provided information on their activity level were included in this study (Estonia: n = 2,018; Latvia: n = 2,303; Lithuania: n = 2,140). RESULTS: One in three Estonians and one in five Latvians and Lithuanians had a low physical activity level at work. Half the respondents (Lithuania: 60%, Latvia: 52%, Estonia: 43%) participated only in sedentary activities during their leisure time. Leisure-time sedentarity was inversely related to education level in men and women and with income in men. It was also associated with smoking in men and with inadequate vegetable intake in men and women. CONCLUSIONS: Sedentary behavior during leisure time should be a public health issue in the Baltic Republics. Health promotion strategies aiming at increasing leisure-time physical activity level will need to target the general population, but particularly individuals from lower socioeconomic strata.

Adolescent↗
PubMed2000

Epidemiological evidence on the carcinogenicity of silica: factors in scientific judgement.

In view of the extended debate and differing opinions on whether crystalline silica is a human carcinogen, we have reviewed a selection of epidemiological reports, to identify the areas of uncertainty and disagreement. We have chosen to examine the papers which in a recent review were considered to provide the least confounded examinations of an association between silica exposure and cancer risk. We also refer to a study of the mortality of coalminers very recently reported by ourselves and colleagues. We find that parts of the evidence are coherent but there are contradictions. On examination this resolves mostly into differences between types of studies. The three types of epidemiological study included are: (i) exposure-response studies, the most powerful for the confirmation of a relationship between a specific exposure and a health effect; (ii) descriptive studies in which incidence of disease in an exposed population is compared with that in a reference population; and (iii) studies of incidence of disease in subjects on silicosis case-registers. Descriptive studies frequently though not invariably suggest an excess lung cancer risk in silica-exposed workers compared with the general population, but exposure-response studies consistently fail to confirm that the cause is exposure to quartz. A single exposure-response study of cristobalite suggests a positive relation. Both sets of evidence have weaknesses. There are uncertainties on whether the excess risks in the descriptive studies are related to silica exposure or to lifestyle, including smoking habits. There are doubts on whether the exposure estimates in some of the exposure-response studies were sufficiently reliable to detect a small risk or weak association, though they are unlikely to have missed a strong effect. Studies of subjects on silicosis case registers consistently show an excess of lung cancer, but it is not clear to what extent these increased risks represent a direct effect of silica exposure, a secondary effect of the silicosis, preferential inclusion of subjects suffering from the effects of smoking, or bias in diagnostic accuracy. This not unnaturally leads to differences in opinion, exacerbated by variations in the strength of proof required by different experts. The main scientific uncertainties in the evidence are: 1. Whether, in the descriptive studies, the excess lung cancer rates in silica-exposed workers are explicable in terms of smoking habits, socio-economic class differences and inappropriate comparison populations. Better smoking information and more carefully chosen comparison populations are needed; 2. Whether the exposure-response studies could have missed a real relationship between silica exposure and lung cancer, if one exists. Many of the exposure-response studies were conducted with great care, but weaknesses, in the available data on which the exposure estimations were based, could have caused a real relationship of lung cancer and silica exposure to be missed. These studies were sufficiently powerful to demonstrate relationships of silica exposure with silicosis and silico-tuberculosis, so it is unlikely that they would have missed any but a small risk, or weak relationship, for lung cancer. Our own recent study of coalminers used uniquely detailed and reliable exposure data, and failed to demonstrate convincingly an increased risk. This negative finding, though, applies only to a dust in which the proportion of quartz in the dust is usually less than 10%. Exposure-response studies are needed, with high quality exposure estimates, in populations exposed to respirable dust of which crystalline silica comprises more than 10%; 3. Whether the excess cancer risks in subjects on silicosis registers are the result of selection and diagnostic bias. Given these difficulties, case-register studies may not be capable of giving a reliable answer to the central question, though they have been useful in pointing to the possibility of a can

Carcinogens↗