Tomato Ve disease resistance genes encode cell surface-like receptors

In tomato, Ve is implicated in race-specific resistance to infection by Verticillium species causing crop disease. Characterization of the Ve locus involved positional cloning and isolation of two closely linked inverted genes. Expression of individual Ve genes in susceptible potato plants conferred resistance to an aggressive race 1 isolate of Verticillium albo-atrum. The deduced primary structure of Ve1 and Ve2 included a hydrophobic N-terminal signal peptide, leucine-rich repeats containing 28 or 35 potential glycosylation sites, a hydrophobic membrane-spanning domain, and a C-terminal domain with the mammalian E/DXXXLphi or YXXphi endocytosis signals (phi is an amino acid with a hydrophobic side chain). A leucine zipper-like sequence occurs in the hydrophobic N-terminal signal peptide of Ve1 and a Pro-Glu-Ser-Thr (PEST)-like sequence resides in the C-terminal domain of Ve2. These structures suggest that the Ve genes encode a class of cell-surface glycoproteins with receptor-mediated endocytosis-like signals and leucine zipper or PEST sequences.

Induced myelination and demyelination in a conditional mouse model of Charcot-Marie-Tooth disease type 1A

Charcot-Marie-Tooth disease type 1A, a hereditary demyelinating neuropathy, is usually caused by overexpression of peripheral myelin protein 22 (PMP22) due to a genomic duplication. We have generated a transgenic mouse model in which mouse pmp22 overexpression can be regulated. In this mouse model, overexpression of pmp22 occurs specifically in Schwann cells of the peripheral nerve and is switched off when the mice are fed tetracycline. Overexpression of pmp22 throughout life (in the absence of tetracycline) causes demyelination. In contrast, myelination is nearly normal when pmp22 overexpression is switched off throughout life by feeding the mice tetracycline. When overexpression of pmp22 is switched off in adult mice, correction begins within 1 week and myelination is well advanced by 3 months (although the myelin sheaths are still thinner than normal), indicating that the Schwann cells are poised to start myelination. Upregulation of the gene in adult mice (which had previously had normal pmp22 expression) is followed by active demyelination within 1 week, which had plateaued by 8 weeks. This indicates that Schwann cells with mature myelin are sensitive to increased amounts of pmp22 such that they rapidly demyelinate. Thus, demyelination can largely be corrected within a few months, but the correction will be sensitive to subsequent upregulation of pmp22.

Structural Studies in Solution of the Recombinant N-Terminal Pair of Short Consensus/Complement Repeat Domains of Complement Receptor Type 2 (CR2/CD21) and Interactions with Its Ligand C3dg

Human complement receptor type 2 (CR2, CD21) is a cell surface receptor that binds three distinct ligands (complement C3d, Epstein-Barr virus gp350/220, and the low-affinity IgE receptor CD23) via the N-terminal two of fifteen or sixteen short consensus/complement repeat (SCR) domains. Here, we report biophysical studies of the CR2 SCR 1-2 domain binding to its ligand C3dg. Two recombinant forms of CR2 containing the SCR 1-2 and SCR 1-15 domains were expressed in high yield in Pichia pastoris and baculovirus, respectively. Circular dichroism spectroscopy showed that CR2 SCR 1-2 receptor possessed a beta-sheet secondary structure with a melting temperature of 59 degrees C. Using surface plasmon resonance, kinetic parameters for the binding of either CR2 SCR 1-2 or the full-length SCR 1-15 form of CR2 showed that the affinity of binding to immobilized C3d is comparable for the SCR 1-15 compared to the SCR 1-2 form of CR2. Unexpectedly, both the association and dissociation rates for the SCR 1-15 form were slower than for the SCR 1-2 form. These data show that the SCR 1-2 domains account for the primary C3dg binding site of CR2 and that the additional SCR domains of full-length CR2 influence the ability of CR2 SCR 1-2 to interact with its ligand. Studies of the pH and ionic strength dependence of the interaction between SCR 1-2 and C3d by surface plasmon resonance showed that this is influenced by charged interactions, possibly involving the sole His residue in CR2 SCR 1-2. Sedimentation equilibrium studies of CR2 SCR 1-2 gave molecular weights of 17 000, in good agreement with its sequence-derived molecular weight to show that this was monomeric. Its sedimentation coefficient was determined to be 1.36 S. The complex with C3d gave molecular weights in 50 mM and 200 mM NaCl buffer that agreed closely with its sequence-derived molecular weight of 50 600 and showed that a 1:1 complex had been formed. Molecular graphics views of homology models for the separate CR2 SCR 1 and SCR 2 domains showed that both SCR domains exhibited a distribution of charged groups throughout its surface. The single His residue is located near a long eight-residue linker between the two SCR domains and may influence the linker conformation and the association of C3d and CR2 SCR 1-2 into their complex. Sedimentation modeling showed that the arrangement of the two SCR domains in CR2 SCR 1-2 is highly extended in solution.

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.

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.

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.

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.

Successful free flap transfer and salvage in sickle cell trait

The presence of sickle cell haemoglobin is generally regarded as a contraindication to free tissue transfer. We present the case of a 42-year-old male with sickle cell trait who had free transfer of a latissimus dorsi flap to cover a gunshot wound to his thigh. His initial haemoglobin S was 36%. Early flap failure from venous thrombosis was successfully salvaged by re-anastomosis to alternative vessels.

Use of patches and whole body sampling for the assessment of dermal exposure

There has been a growing awareness of the importance of dermal exposure in recent years. A wide range of techniques are employed to measure exposure, of which surrogate skin techniques such as patch sampling and whole body sampling are frequently used. One of the problems associated with dermal sampling is that different methods often produce different results due to differences in the principles involved in sample collection. As a consequence little progress towards establishing dermal exposure limits has been made. Both patches and clothing act as passive samplers and are intended to collect all of a substance deposited on them. This paper details the principles underlying patch and whole body sampling and outlines some of the advantages and disadvantages of each. A conceptual model has recently been proposed for dermal exposure and the role that surrogate techniques may play in the application of this model is discussed. Finally, suggestions are made as to how these techniques may be made more relevant and areas of future research highlighted.

Long-term prognosis of crown-fractured permanent incisors. The effect of stage of root development and associated luxation injury

OBJECTIVES

The aim of the present study was to investigate pulp healing responses following crown fracture with and without pulp exposure as well as with and without associated luxation injury and in relation to stage of root development. PATIENT MATERIAL AND METHODS: The long-term prognosis was examined for 455 permanent teeth with crown fractures, 352 (246 with associated luxation injury) without pulpal involvement and 103 (69 with associated luxation injury) with pulp exposures. Initial treatment for all patients was provided by on-call oral surgeons at the emergency service, University Hospital (Rigshospitalet), Copenhagen. In fractures without pulpal involvement, dentin was covered by a hard-setting calcium hydroxide cement (Dycal), marginal enamel acid-etched (phosphoric acid gel), then covered with a temporary crown and bridge material. In the case of pulp exposure, pulp capping or partial pulpotomy was performed. Thereafter treatment was identical to the first group. Patients were then referred to their own dentist for resin composite restoration.

RESULTS

Patients were monitored for normal pulp healing or healing complications for up to 17 years after injury (x = 2.3 years, range 0.2-17.0 years, SD + 2.7). Pulp healing was registered and classified into pulp survival with no radiographic change (PS), pulp canal obliteration (PCO) and pulp necrosis (PN). Healing was related to the following clinical factors: stage of root development at the time of injury, associated damage to the periodontium at time of injury (luxation) and time interval from injury until initial treatment. Crown fractures with or without pulp exposure and no concomitant luxation injury showed PS in 99%, PCO in 1% and PN in 0%. Crown fractures with concomitant luxation showed PS in 70%, PCO in 5% and PN in 25%. An associated damage to the periodontal ligament significantly increased the likelihood of pulp necrosis from 0% to 28% (P < 0.001) in teeth with only enamel and dentin exposure and from 0% to 14% (P < 0.001) in teeth with pulp exposure.

CONCLUSIONS

In the case of concomitant luxation injuries, the stage of root development played an important role in the risk of pulp necrosis after crown fracture. However, the primary factor related to pulp healing events after crown fracture appears to be compromised pulp circulation due to concomitant luxation injuries.

Intramedullary nailing of tibial fractures: how often are post-operative radiographs needed?

A series of 53 closed tibial fractures were treated with interlocking intramedullary nailing. Excluding the routine postoperative radiographs at the time of surgery, a median number of seven radiographs were taken per patient (range 2-13). In total, 343 radiographs were taken after the postoperative film. Of these 343 radiographs, only nine (3%) radiographs led to a decision for clinical intervention. No radiograph in the first 10 weeks after surgery changed management. A reduction in the use of post-operative radiography after tibial nailing is recommended.

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.

2.5-GHz repetition-rate singly resonant optical parametric oscillator synchronously pumped by a mode-locked diode oscillator amplifier system

We report on an optical parametric oscillator (OPO) that is synchronously pumped directly by a diode laser. This laser is an actively mode-locked master-oscillator power-amplifier system that produces 20-ps pulses at 927 nm with a repetition rate of 2.5 GHz and an average power of 0.9 W. The OPO, which is a singly resonant device based on periodically poled lithium niobate, generates 7.8-ps pulses. The OPO threshold is 300 mW of average pump power, and the maximum average idler output power is 78 mW at a wavelength of 2100 nm. By changing the crystal temperature we can wavelength tune the output in the ranges 1530-1737 nm (signal) and 1986-2348 nm (idler). Rapid wavelength tuning of the OPO over 46 nm (signal) and 74 nm (idler) is achieved through tuning the cavity length over 28 microm by use of a piezoelectric transducer.

Leptin-induced decrease in food intake in chickens

The effect of intracerebroventricular (i.c.v.) injection of leptin was investigated using broiler and Single Comb White Leghorn (SCWL)-type chickens. These represent relatively fast- and slow-growing birds, respectively. The i.c.v. injection of leptin decreased food intake in both broilers and Leghorns in a dose-dependent manner. The most efficacious dose appeared to be 10 microg in both types of chickens. Water intake was generally not affected by leptin, indicating that this effect was not due to general malaise. It appears that leptin can act within the central nervous sytstem of birds to decrease food intake.

Alcohol consumption in the Baltic Republics

STUDY OBJECTIVES

Premature mortality associated with alcohol intake is of particular concern in several countries of the former Soviet Union. This study explored self reported alcohol consumption (beer, wine, spirits) and its determinants in the Baltic Republics.

DESIGN

Cross sectional surveys conducted in 1997.

SETTINGS

Estonia, Latvia and Lithuania.

PARTICIPANTS

Representative samples of adults age 19-64 (Estonia n=2010; Latvia n=2258; Lithuania n=2139).

METHODS

Between country differences in the frequency of alcohol intake were estimated. The odds of consuming alcohol weekly according to socioeconomic characteristics (age, ethnicity, rural/urban area, education, income) were calculated using multiple logistic regression analyses, adjusting for all variables simultaneously.

MAIN RESULTS

The proportion of respondents consuming alcohol weekly varied by country (p<0.001) (men: Estonia=61% Latvia=41% Lithuania=55%; women: Estonia=26% Latvia=8% Lithuania=14%). Within each country, this proportion decreased with age in both sexes (p<0. 001), and increased with income in women (p<0.01). In Estonia, the odds of drinking alcohol weekly was significantly lower in respondents of Russian than of Estonian ethnicity (odds ratios (OR) and 95% confidence intervals (95%CI): men=0.51 (0.36, 0.71); women=0. 57 (0.39, 0.81)). In Lithuania, the odds was higher in highly educated men than in those with a low education level (OR=1.48 (1.01, 2.17)). Daily alcohol intake was higher in Estonia than in the other countries, as was the percentage of respondents drinking heavily (equivalent to 80 g/day).

CONCLUSIONS

Approximately half the men and one in six women in the Baltic States reported consuming alcohol at least weekly. Age and income were the strongest and most consistent correlates of the likelihood of consuming alcohol weekly. Ethnic differences were observed only in Estonia.

Respiratory syncytial virus infection in children hospitalised with acute lower respiratory tract infection

BACKGROUND

Data are lacking on respiratory syncytial virus. (RSV) respiratory tract infections in children from developing countries.

OBJECTIVE

To determine the importance of RSV as a cause of acute lower respiratory tract infection (ALRTI) in Cape Town children.

METHODS

Children younger than 2 years of age admitted to hospital with ALRTI over a 15-month period from 1 June 1995 to 31 August 1996 were studied prospectively. Sociodemographic data, risk factors for severe RSV disease, clinical signs, diagnosis and hospital course were documented. A nasopharyngeal aspirate (NPA) for detection of RSV by enzyme immunoassay (EIA) was obtained in all cases. The NPA of every fifth child was sent for viral culture.

RESULTS

A total of 1,288 patients (60% male, 40% female) with a median age (25th-75th percentile) of 6 months (2-11 months) was enrolled; 32.4 had one or more risk factors for severe RSV infection. Pneumonia was diagnosed in 62.2%, bronchiolitis in 20.6%, laryngotracheobronchitis (LTB) in 8% and other respiratory illnesses in 9.2%. Mild disease, requiring admission to an overnight ward, was documented in 38.1%, while 48.9% and 13% respectively had moderate and severe disease requiring admission to a general ward and intensive care unit (ICU). Supplemental oxygen and mechanical ventilation were required by 68.9% and 8.5% of patients, respectively. The median duration of hospital stay was 5 days (range 1-10 days). RSV EIA was positive in 16.4% of cases, and there was no difference in detection rates according to diagnosis. Viral culture performed in 162 of the 1,288 study patients (12.6%) grew RSV in 11.7% of cases, adenovirus in 3.7%, para-influenza virus type 3 in 2.5% and influenza B virus in 0.6%. Patients who tested RSV EIA-positive did not significantly differ from those who tested negative with regard to demographic variables, clinical diagnoses, risk factors for RSV or length of hospitalisation. The only significant difference noted was the presence of hyperinflation, which occurred in 70.1% of EIA-positive patients compared with 57.1% of those testing negative (P = 0.0005). The mortality rate (2%) was similar for both groups.

CONCLUSION

This study indicates that RSV is an important cause of hospitalisation in infants and young children with ALRTI. Distinguishing RSV from other ALRTIs is difficult because of similarity in clinical presentation among children.

Early discharge with drain in situ following axillary lymphadenectomy for breast cancer

One-hundred and two women had axillary lymphadenectomy for breast cancer and were randomised to early discharge with axillary drain in situ on the third postoperative day or standard duration 7 day hospital stay. The two groups did not differ with respect to seroma formation, wound infection or psychological profile as measured by the Hospital Anxiety and Depression Scale and Spielberger State Trait and Anxiety Inventory. Patient satisfaction levels were high in the early discharge group. The results confirm that early discharge after axillary lymphadenectomy is safe, practicable and satisfactory for patients. Such a policy offers considerable resource savings.

The effect of head position on the distribution of drops within the nose

Nose drops are commonly prescribed in the United Kingdom, yet clinicians vary considerably in the instructions they give on how to instill them. This is important because how they are used affects how well they work. In this study, a visual assessment of the intranasal distribution of drops was made using endoscopic examination after the instillation of betamethasone drops containing methylene blue. Drops instilled with the head tipped back were found along the nasal floor and in the nasopharynx, with none visible in the middle meatus or elsewhere on the lateral nasal wall. Drops instilled in Mygind's position or in the praying-to-Mecca position were found predominantly in the middle meatus and on the middle and inferior turbinates. No difference was seen between these two positions in the distribution of drops achieved, and this is likely to lead to similar clinical efficacy. Because Mygind's position is much more comfortable for patients, it should be recommended by all doctors prescribing nose drops.

Outcomes analysis of verbal dyspraxia in classic galactosemia

PURPOSE

This study evaluates a genotype/phenotype relationship between developmental verbal dyspraxia (DVD) and the common, missense mutation of the galactose-1-phosphate uridyltransferase gene, Q188R, in patients with classic galactosemia (G/G).

METHODS

As part of this study, we devised a questionnaire for "speech problems" to be completed by the patient\'s clinician. To validate the questionnaire and determine its accuracy in detecting DVD, we analyzed questionnaire responses for 21 patients by testing them independently and directly for DVD through a speech pathologist blinded to the patients' genotype.

RESULTS

We found that the questionnaire had a sensitivity of 0.56 and a specificity of 0.75. We then calculated the prevalence of DVD for a larger set of 113 patients with G/G galactosemia whose biochemical phenotype, molecular genotypes, and clinical status were known. The prevalence of "speech problems" from raw data were 50 of 113 (44.2%). After adjusting for misclassification, 43 (38.1%) were classified as cases of DVD. Using multivariate, logistic, regression analyses we found a significant interaction between genotype and mean red blood cell (RBC) galactose-1-phosphate (Gal-1-P). When corrected, using mean RBC Gal-1-P < h 3.28 mg%, the Q188R/Q188R genotype was the best predictor of DVD. There was a significant risk (odds ratio = 9.6, p = 0.0504) of having DVD associated with homozygosity for Q188R compared with other genotypes.

CONCLUSIONS

We conclude that homozygosity for Q188R mutations in the GALT gene is a significant risk factor for DVD. However, poor metabolic control obviates this relationship as indicated by RBC Gal-1-P greater than 3.28 mg%.

Patterns of body weight in the Baltic Republics

OBJECTIVE

Previously recorded rates of obesity in the Baltic Republics have been among the highest in the world although little is known about how they vary within the population. This study investigates the distribution of body mass index (BMI) and obesity in these countries.

DESIGN

Three cross-sectional surveys conducted in the summer of 1997.

SETTING

Estonia, Latvia and Lithuania.

SUBJECTS

Representative national samples of adults with measured weight and height (Estonia: n=1154; Latvia: n=2292; Lithuania: n=2096).

RESULTS

Between-country differences are particularly large among women: women from Latvia and Lithuania are approximately three times as likely to be obese as those from Estonia (17.4%, 18.3%, 6.0% respectively); only about one-third of this difference is explained by the sociodemographic and behavioural factors studied. In men, the prevalence of obesity varied only slightly among countries (Estonia: 9.9%; Latvia: 9.5%; Lithuania: 11.4%). While the prevalence of obesity increases with age within each republic, particularly in women, it is not associated with nationality or urban/rural region, and no consistent association is observed with income. Obesity is inversely related to education in Latvia and in Lithuanian women. Latvian men and women and Lithuanian men who smoked had a lower prevalence of obesity than non-smokers. Leisure time physical activity was not associated with obesity.

CONCLUSIONS

Obesity is a major health problem in the Baltic Republics, particularly among Latvian and Lithuanian women. The lack of association between obesity and most demographic, socioeconomic and behavioural factors suggests that the problem is generalized. Health promotion strategies aiming at preventing and controlling excess weight gain in the Baltic Republics will need to target the general population.

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

Food, health, and the urban environment

Both the production and the consumption of food should help reduce the risk of food-borne and non-communicable disease and prevent micro-nutrient deficiency. That a safe healthy diet can also be environmentally sound is a bonus. Growing foods that promote health in an environment near to consumers can contribute to reduced fuel consumption, pollution, transport and packaging costs, and can promote biodiversity. This approach can also help create local jobs, improve access to food, and promote a sustainable environment. The World Health Organization recommends an intake of more than 400 grams of vegetables (in addition to potatoes) and fruit every day because this helps prevent non-communicable diseases and micro-nutrient deficiency. Therefore, urban food and nutrition policies are needed to promote health through an integrated approach to food, health, and the environment within local communities. The benefits of developing urban food and nutrition policies to help increase local food production include environmental, social, direct, and indirect economic benefits, in addition to the health benefits. These issues are discussed in this paper.

Recommended permissible noise criteria for occupied, newly constructed or renovated hospital nurseries. The Sound Study Group of the National Resource Center

OBJECTIVE

To base permissible noise criteria for occupied, new nurseries on research findings.

STUDY DESIGN

An interdisciplinary group of clinicians reviewed the literature regarding the effect of sound on the fetus, newborn, and preterm infant and based recommended criteria on the best evidence. An external panel subsequently reviewed the criteria.

RESULTS

The recommended criteria: Patient bed areas and the spaces opening onto them shall be designed to produce minimal ambient noise and to contain and absorb much of the transient noise that arises within the nursery. The overall, continuous sound in any bed space or patient care area shall not exceed: (1) an hourly Leq of 50 dB and (2) an hourly L10 of 55 dB, both A-weighted, slow response. The 1-second duration Lmax shall not exceed 70 dB, A-weighted, slow response.

CONCLUSION

The permissible noise criteria will protect sleep, support stable vital signs, and improve speech intelligibility for many infants most of the time.

Sound transmission into incubators in the neonatal intensive care unit

OBJECTIVE

To measure the attenuation of sound by modern incubators.

STUDY DESIGN

LEQ, LMAX, LPEAK, and frequency distribution were measured simultaneously inside and outside two recent model incubators.

RESULTS

The attenuation of sound (outside minus inside) was 15 to 18 dBA with the motor off and 4 to 8 dBA with the motor on. There was a significant difference between incubators in their attenuation of sound. Octave band analysis showed attenuation in frequency bands of > 31.5 Hz with the motor off. With the motor on, the sound level inside the incubator was higher than outside at frequency bands of < 250 Hz.

CONCLUSION

Caring for infants inside modern incubators reduces "averaged" sound exposure to levels near those recommended for the neonatal intensive care unit. Lower frequency sounds are louder inside the incubator and arise from the incubator motor.

AIDS knowledge, condom attitudes, and risk-taking sexual behavior of substance-abusing juvenile offenders on probation or parole

AIDS knowledge, condom attitudes, and sexual behavior were examined in a sample of 193 substance-abusing juvenile offenders on probation or parole. The majority of these youths reported being sexually active, and many admitted to early onset of sexual activity as well as unsafe sexual practices. Potential predictors of condom use by these juveniles were examined including age, condom use at first sexual experience, number of sexual partners in the last 6 months, locus of control, AIDS knowledge, condom attitudes, perceived risk for AIDS, self-efficacy for avoiding HIV, condom use by peers, delinquency risk, race, and gender. General attitudes toward condoms and the reported use of a condom at first sexual intercourse experience were the only statistically significant predictors of subsequent condom use. The relevance of these findings to the development of AIDS prevention programs for juvenile offenders is discussed.