Risk-taking behavior and accidents in adolescence in developed countries

Injuries due to accidents are the primary cause of fatalities among adolescents. Between the ages of 10 and 19, mortality caused by accidents augments significantly, and there is an excess of male mortality, increasing with age. This mortality has remained virtually unchanged over the past 25 years, except for a small narrowing of rate differences by sex. Traffic accidents, particularly those involving motorcycles, are the leading cause of accident fatalities. Though not easily assessed, morbidity due to accidents is probably very high, especially among males. Sports accidents are the most frequent. Adolescents appear to be particularly exposed to some risks, but also tend to be careless about safety. Risk-taking is a source of rewards: pleasure, self-affirmation, sense of independence; but it is described by some authors as self-destructiveness, death from accidents reflecting suicidal tendencies. Paradoxical results of prevention have been observed in this age group.     

Polychlorinated biphenyls and human health

Polychlorinated biphenyls (PCBs) were manufactured and used widely for many years. Because they are very persistent in both the environment and biological systems, there has been significant global contamination. This review presents a summary of known or suspected health effects of various PCB congeners, documented on the basis of both human and animal studies. As our knowledge increases several important points become apparent. PCBs interfere with many biological functions, including the immune system, the nervous system, and several endocrine system, and the fetus appears to be particularly vulnerable to these actions. PCBs cause certain cancers in animals. PCBs are mixtures of multiple congeners, differing on the basis of the numbers and positions of chlorines around the biphenyl ring, and it is becoming increasingly apparent that different congeners may have very different actions. These observations suggest that the potential human health hazards from PCB exposure have been underappreciated.     

Triage of back pain by physiotherapists in orthopaedic clinics.

In 1994 we described a system whereby certain patients with back pain, on referral to an orthopaedic clinic, were seen first by a physiotherapist who referred on only the problem cases and those in need of surgery ('triage'). This practice has grown rapidly but there have been difficulties. To clarify these we have carried out a postal questionnaire. The results reveal similar practices in most centres but some discrepancies that are cause for concern. These relate to the workload of the physiotherapist, informed consent, supervision and accountability, the type of cases seen and not least the stresses on the physiotherapist. We believe the triage system has many benefits, but if it is not to be derailed the issues of concern must be addressed and the posts properly structured.     

Comparison of binge eating disorder and bulimia nervosa in a community sample.

OBJECTIVE: This study examined the relationship between binge eating disorder (BED), a newly proposed eating disorder, and bulimia nervosa (BN). METHOD: Three groups recruited from the community were compared: women with BED (n = 150), women with purging BN (n = 48), and women with nonpurging BN (n = 14). RESULTS: The three groups did not differ significantly in education, weight or shape concern, and current or lifetime prevalence of nine major mental disorders. Women with BED, compared with women with purging BN, were older, less likely to have a history of anorexia nervosa, and less likely to have been treated for an eating disorder. Obesity was more commonly associated with BED than with either subtype of BN. DISCUSSION: Our results lend some support to BED as an eating disorder distinct from purging BN. More research is needed to clarify the position of nonpurging BN relative to BED and purging BN.     

CERTAIN characteristics of BCG-induced tuberculin sensitivity

Post-vaccination tuberculin sensitivity is being used to evaluate the immediate effects of the extensive WHO/UNICEF mass BCG vaccination programmes currently in progress. During the past five years the Tuberculosis Research Office has been studying the tuberculin sensitivity produced by BCG vaccination, and the present paper discusses some of the most important characteristics of BCG-induced allergy. The material for the paper was drawn from the results in five countries of vaccinating more than 6,000 schoolchildren and retesting them at one or more intervals after vaccination.Tuberculin sensitivity produced by BCG is not the kind of response that may logically be described as "positive" or "negative". Rather, vaccination always produces, or increases, sensitivity to tuberculin, although, with some vaccines and in some persons, the degree of sensitivity produced may be low. BCG-induced allergy can best be described by the distribution of the sizes of the tuberculin reactions and summarized by the mean and standard deviation of the distribution. The common practice of classifying post-vaccination reactions as "positive" or "negative" is biologically meaningless and may be the cause of many fallacious notions about the allergy produced by BCG.The degree of post-vaccination allergy varies with the potency of the vaccine used: a potent vaccine has been shown to produce allergy about as strong as that produced by natural infection wherever carefully controlled studies have been made. No evidence was found that allergy wanes or is lost after intradermal vaccination: the impression that it does so may often have been the consequence of the practice of revaccination and of ignoring the influence of experimental error. Unless very weak vaccines are used, there is no indication that superinfection can be identified after vaccination. The diagnostic value of the tuberculin test is thus being destroyed in many places where mass campaigns are being done, particularly in those places where a high degree of tuberculin sensitivity is being produced.     

Dietary antioxidants, peroxidation and cardiovascular risks

Most of the many epidemiological studies in the field strongly suggest that an equilibrated diet such as the so-called "mediterranean diet", is associated with protective effects against major diseases, and particularly, against cardiovascular risks. Since many reports also consider reactive oxygen species or free radical oxidations to be responsible for the accompanying disorders of most pathologies as well as for ageing, it is conceivable that natural plant metabolites such as polyphenols, are likely to play an important role in insuring this protection. Indeed, not only their presence, in particularly high amounts and varieties in foods of such a diet, but also, inter alia, their very potent antioxidant or radical scavenging properties, make polyphenols best accounting for the parodoxical part of the french paradox . Therefore, many efforts have been made to assess the mechanisms for such a cardiovascular disease protection. Whatever convincing were the polyphenols properties demonstrated by many in vitro experiments to support those theories, quite a great number of the results appeared somewhat contradictory when transposed to humans, in the in vivo situation. Some people totally refute this explanation, thinking that health benefits, as far as alcoholic beverages are concerned, originate from ethanol but also, with no doubt, some polyphenols even revealing to be pro-oxidants .     

Regional cerebral blood flow after recovery from anorexia or bulimia nervosa

OBJECTIVE: Abnormalities of regional cerebral blood flow (rCBF) have been found in individuals who are ill with anorexia (AN) or bulimia nervosa (BN). Little is known about whether rCBF normalizes after recovery from AN and BN. METHOD: Eighteen control women (CW), 10 recovered restricting type AN, 8 recovered AN with a binging history, and 9 recovered BN participants without a history of AN were studied using positron emission tomography and [(15)O]water in order to assess rCBF. RESULTS: Partial volume corrected rCBF values in cortical and subcortical brain regions were similar between groups. Neither current body mass index nor age correlated with rCBF values. CONCLUSION: The results from this study indicate that rCBF normalizes with long-term recovery. Thus, altered rCBF is unlikely to confound functional imaging studies in AN or BN after recovery.     

Primary health care in the Philippines: banking on the barangays?

Primary health care has been hailed by some countries as the only practical means of providing any form of health care for expanding populations in poor economies. This is particularly true in Third World countries where the cost explosion of technology-oriented health care has been a major problem in extending services. Therefore, the PHC package of education, nutrition, preventive medicine and treatment of the most common diseases and injuries is sometimes regarded as the most beneficial application of scarce resources. The Philippines claims to be one of the first (perhaps the first) countries to have adopted PHC as a national strategy for health care and, since 1981, impressive achievements have been attained in this sector by contrast with reversals in many other sectors of the economy. PHC has not challenged the pre-eminence of Metro-Manila in the provision of hospital and specialist facilities but it has extended some basic care particularly to rural regions of the country. This paper reviews the background to health care in the Philippines and it then examines the implementation of PHC in Negros Oriental, where PHC has taken on the additional feature of special use of indigenous materials and resources. The administrative, financial and legal bases and some geographical facets of PHC are highlighted in this province. The campaign relies heavily on local (barangay) initiatives and community participation, in part to minimise resources which have to be devoted to health in a very troubled national economy. In spite of local skills and enthusiasm, this arguably still involves the abrogation of a degree of government responsibility for health care. As a result, the Philippines strategy may be said to be "banking on the barangays."     

The pathogenesis of sleeping sickness

Although the clinical and pathological features of sleeping sickness have been well recognized since the beginning of the century, we still have very little idea about how these changes are brought about. A convincing role for a trypanosome-derived toxin has yet to be established and it is probable that most tissue damage results from an immunopathological reaction. An immediate type hypersensitivity reaction might account for the pruritus and urticaria sometimes encountered in patients with the infection. Autoantibodies are produced by patients with sleeping sickness but it has not been established that these can cause tissue damage. Similarly, although high levels of immune complexes are found in patients with sleeping sickness, it has yet to be clearly established that these damage the brain or heart. The dominant pathological event in sleeping sickness is B lymphocyte proliferation, first within the lymph nodes and then within the brain and meninges, and this response may lead to tissue damage in some way which has not yet been identified. B lymphocyte proliferation could result from the action of a trypanosome-derived mitogen or from interference with T lymphocyte control over B lymphocyte function.     

Bioimpedance spectroscopy for clinical assessment of fluid distribution and body cell mass.

Body composition assessment has been used to evaluate clinical interventions in research trials, and has the potential to improve patient care in the clinical setting. Body cell mass (BCM) is an important indicator of nutrition status; however, its measurement in the clinic has been limited. BCM can be estimated by the measurement of intracellular water (ICW). The assessment of extracellular water (ECW) is also important because many clinical populations undergo alterations in fluid distribution, particularly individuals with wasting, those receiving dialysis, and obese individuals. Bioimpedance spectroscopy (BIS) is a unique bioimpedance approach that differs in underlying basis from the more readily recognized single-frequency bioelectrical impedance analysis (SF-BIA) in that it does not require the use of statistically derived, population-specific prediction equations. It has the potential advantage of not only measuring total body water (TBW), as does SF-BIA, but also offering the unique capacity to differentiate between ECW and ICW and, thus, to provide an estimate of BCM. This literature review was conducted to compare available BIS devices to multiple dilution for measuring fluid compartments or BCM in a number of populations. Variable results regarding the ability of BIS to measure absolute volumes, as well as the observation of wide limits of variation, make BIS problematic for individual assessment in the clinic, particularly in populations with abnormal fluid distribution or body geometry. BIS has been found to be more accurate for measuring changes in fluid volumes or BCM, particularly in post-surgical and human immunodeficiency virus (HIV)-infected individuals. It is certainly possible that population-specific adjustments may improve the accuracy of BIS for assessing individuals in the clinical setting; however, additional research and development is needed before the method can be accepted for routine clinical use.     

Methylphenidate treatment for bulimia nervosa associated with a cluster B personality disorder

OBJECTIVES: Psychotherapy and antidepressant medication are helpful to many patients with bulimia nervosa (BN). However, a substantial number of bulimics respond poorly to such treatments. Recent studies suggest that many of the poor responders have cluster B personality disorders. In some ways, the symptomatology of bulimics who have a comorbid cluster B disorder resembles that of patients with attention deficit hyperactivity disorder (ADHD). In particular, individuals in both groups frequently have a high level of impulsivity. Such a resemblance raised the question of whether administration of methylphenidate (MPH), a drug used to treat ADHD, would have therapeutic effects in this subgroup of BN patients. METHODS: In a pilot study, we administered MPH to 2 patients with BN and cluster B traits and found beneficial effects. These patients had not responded to adequate trials of psychotherapy and selective serotonin reuptake inhibitors (SSRIs). RESULTS: MPH treatment was effective. Both Patients had decreased binging and purging. DISCUSSION: MPH may be useful for bulimics with cluster B personality disorder who respond poorly to conventional treatment. Further studies of MPH administration may be worthwhile. Due to the potential risks, however, clinical treatment with this agent is not recommended at this time.     

Causal relationship between exposure to chemicals and malignant melanoma? A review and study proposal

Malignant melanoma (MM) is a significant cause of morbidity and mortality worldwide. The MM-related incidence and mortality have been increasing at an alarming rate over at least the past four decades. Malignant melanoma has been thought to be related mainly to exposure to the sun or UV radiation. A review of the scientific literature reveals many significant correlations between chemical exposure in the workplace and the occurrence of malignant melanoma, particularly in cutaneous areas that have never been exposed to sunlight. Discrepant findings are reported by independent studies concluding that MM is causally related to employment-related chemical exposures and to investigators with industry affiliations. More studies are needed to define a correlation of chemical exposure as a co-factor on the pathogenesis in some melanoma patients. We propose further investigation by dermatologists working in Melanoma Centers, using a simple questionnaire on chemical exposure among patients, that have previously been diagnosed and are followed up for melanoma comparing with appropriate matched controls. Collecting the data and results from the questionnaire will help us understand the initiation events in melanoma and prevention health issues.     

Pertussis vaccine and severe acute neurological illnesses. Response to a recent review by members of the NCES team

Dr. A. H. Griffith's article on this subject raises some important issues which require comment. We, like him, regret the controversy over the safety and efficacy of whole cell pertussis vaccines over the last 15 years. It does indeed represent a sorry saga whose principal victims are children, many of whom have not been vaccinated against this unpleasant and sometimes dangerous illness because of fears over safety of the vaccine. The National Childhood Encephalopathy Study (NCES), was set up in 1976 as an independent scientific enquiry into severe acute neurological illnesses associated with pertussis vaccine in an attempt to help resolve the matter. The report on the results concluded that these suggested, but did not prove, that the vaccine may very rarely cause the development of potentially damaging severe acute neurological illnesses in children who were previously apparently neurologically normal. Unfortunately the number of cases in the NCES was too small to allow any firm conclusions on whether or not the vaccine can cause permanent damage. The NCES has since been subject to intense scrutiny and criticism both by those who consider the vaccine can cause permanent neurological damage and by those, such as Dr Griffith, who consider it does not. Regrettably, the controversy continues.     

The adaptive response of the immune system to the particular malnutrition of eating disorders

Despite the seriously undernourished state of patients with anorexia nervosa (AN) and bulimia nervosa (BN), controversial findings have been published regarding some aspects of the immune system that are otherwise impaired in more typical types of malnutrition, such as protein-energy malnutrition. In general, adaptation processes seem to occur enabling immune function to be preserved during long periods of the illness. However, cell-mediated immunity is usually altered in AN and BN as reflected by lymphocyte subset counts and the response to delayed hypersensitivity tests. Regarding the helper/cytotoxic T cell ratio (CD4:CD8), an immunological marker of the nutritional status, the results of our studies on AN and BN patients showed that the duration of the eating disorder and the time when appropriate treatment is achieved are likely contributors to the alteration of this ratio. Despite these findings, it has been repeatedly pointed out that anorexic patients seem to be free of common viral infections at least until the most advanced stages of debilitation. Some hypotheses that could explain the lack of infection symptoms are reviewed. Cytokines and the altered acute phase response to infection, as well as cortisol and leptin, are considered to be potential factors involved in the adaptation processes occurring in these syndromes. Further progress in the knowledge of the psychoneuroendocrine-immune interactions established in AN and BN will be relevant to the understanding of the aetiology and maintenance mechanisms of these pathologies.     

An examination of five spatial disease clustering methodologies for the identification of childhood cancer clusters in Alberta, Canada

Cluster detection is an important part of spatial epidemiology because it may help suggest potential factors associated with disease and thus, guide further investigation of the nature of diseases. Many different methods have been proposed to test for disease clusters. In this paper, we study five popular methods for detecting spatial clusters. These methods are Besag-Newell (BN), circular spatial scan statistic (CSS), flexible spatial scan statistic (FSS), Tango's maximized excess events test (MEET), and Bayesian disease mapping (BYM). We study these five different methods by analyzing a data set of malignant cancer diagnoses in children in the province of Alberta, Canada during 1983-2004. Our results show that the potential clusters are located in the south-central part of the province. Although, all methods performed very well to detect clusters, the BN and MEET methods identified local as well as general clusters.     

Yersinia enterocolitica : a review of its role in food hygiene.

Since Yersinia enterocolitica, now classified as a member of the Enterobacteriaceae, was recognized as a distinct species in 1964 it has been isolated with increasing frequency from man and animals (including dogs and pigs) and from some human foods. Y. enterocolitica infections are now seen as a cause for some concern in both human and veterinary medicine. The organism is commonly found in specimens from swine slaughterhouses and has been isolated from samples of market meat, vacuum-packed beef, mussels, oysters, and ice-cream. It has also been found in nonchlorinated well water used for drinking purposes. Infections in man therefore probably have an alimentary origin. Only 23 human infections were recorded in 1966 but the number increased to over 4000 in 1974. However, reported incidence is affected by growing awareness about the role of the organism in human and animal disease and by intensive laboratory analyses. While knowledge about the geographical distribution of Y. enterocolitica is still fragmentary it is clear that infections are very frequent in some parts of the world and probably common but unrecognized in many countries. The most common symptoms of Y. enterocolitica infections in man are fever, abdominal pain, and diarrhoea. In the USA most isolations in human infections were made from blood and mesenteric lymph node samples. The pathogenic mechanism is not known. In one experiment involving a human volunteer subject a dose of 3.5 × 10⁹ organisms was required to produce an infection. Only recently has some success been obtained in establishing experimental infections in mice, guinea-pigs, rats, and rabbits. Laboratory cultivation techniques for Y. enterocolitica are described together with a table of minimal tests for characterizing the organism and two biotyping schema. Little is known about methods for controlling this disease, but environmental hygiene and sanitation with regard to food and water should apply.     

Walkie talkies cause more electromagnetic interference to medical equipment than mobile phones

It is generally realised that mobile phones can interfere with medical electrical equipment and many hospitals have policies which aim to minimise the risk to their patients from this cause. Walkie talkies are also used in hospitals, but very little information is available concerning their ability to interfere with hospital equipment. Two walkie talkies and three mobile phones have been used to study and compare interference in 29 items of patient-connected equipment in a large hospital. Test results show that with some equipment there will be signal distortion and/or false alarms, and a Power off/on Reset may be necessary. In rare cases, when equipment is subjected to extreme signal strengths, it is possible to observe equipment failure requiring the replacement of failed components. For these tests the walkie talkies were set at 4W of output power and they caused significantly more interference than the mobile phones. The observed effects have been classified according to the maximum distance at which they were observed and according to the criticality of the possible outcome for the patient. It is concluded that, except for emergency services, the use of walkie talkies should be restricted in hospital buildings.     

Occupational skin cancers

Skin cancer due to occupation is more common than is generally recognized, although it is difficult to obtain an accurate estimate of its prevalence. Over the past two centuries, occupational skin cancers have particularly been due to industrial exposure of men (it seems more so than women) to chemical carcinogens such as polycyclic hydrocarbons (e.g. from coal tar products) or to arsenic. Industrial processes have improved in most Western countries to limit this type of exposure, but those with outdoor occupations are still exposed to solar ultraviolet irradiation without this being widely recognized as an industrial hazard. Ionizing radiation such as X-rays can also cause skin cancer. Occupational skin cancers often resemble skin tumours found in non-occupational subjects, e.g. basal cell carcinoma, squamous cell carcinoma and malignant melanoma, but some pre-malignant lesions can be more specific and point to an occupational origin, e.g. tar keratoses or arsenical keratoses. An uncommon but well-recognized cause of occupational skin cancer is that which results from scar formation following an industrial burn. In the future it will be necessary to focus on preventative measures, e.g. for outdoor workers, the need to cover up in the sun and use sun protective creams and a campaign for earlier recognition of skin cancers, which are usually curable if treated in their early stages.     

Methyl-tert-hexyl ether and methyl-tert-octyl ether as gasoline oxygenates: anticipating widespread risks to community water supply wells

The widespread contamination of groundwater resources associated with methyl-tert-butyl ether (MtBE) use has prompted a search for replacement oxygenates in gasoline. Among the alternatives currently under development are higher methyl-tert-alkyl ethers, notably methyl-tert-hexyl ether (MtHxE) and methyl-tert-octyl ether (MtOcE). As was the case with MtBE, the introduction of these ethers into fuel supplies guarantees their migration into groundwater resources. In the present study, a screening-level risk assessment compared predicted well water concentrations of these ethers to concentrations that might cause adverse effects. A physicochemical model which has been successfully applied to the prediction of MtBE concentrations in community water supply wells (CSWs) was used to predict well water concentrations of MtHxE and MtOcE. The results indicate that these ethers are likely to contaminate water supply wells at slightly lower levels than MtBE as a result of migrating from leaking underground fuel tanks to CSWs. Because very little data is available on the physicochemical and environmental properties of MtHxE and MtOcE, estimation methods were employed in conjunction with the model to predict well water concentrations. Model calculations indicated that MtHxE and MtOcE will be present in many CSWs at concentrations approaching the concentrations that have caused widespread public health concern for MtBE. Based on these results and the possibility that MtHxE and MtOcE are potential carcinogens, testing of the toxicological properties of these ethers is recommended before they are used to replace MtBE in gasoline.