Nipah virus infection among abattoir workers in Malaysia, 1998-1999

BACKGROUND

An outbreak of encephalitis primarily affecting pig farmers occurred during 1998-1999 in Malaysia and was linked to a new paramyxovirus, Nipah virus, which infected pigs, humans, dogs, and cats. Because five abattoir workers were also affected, a survey was conducted to assess the risk of Nipah infection among abattoir workers.

METHODS

Workers from all 143 registered abattoirs in 11 of 13 states in Malaysia were invited to participate in this cross-sectional study. Participants were interviewed to ascertain information on illness and activities performed at the abattoir. A serum sample was obtained to test for Nipah virus antibody.

RESULTS

Seven (1.6 %) of 435 abattoir workers who slaughtered pigs versus zero (0%) of 233 workers who slaughtered ruminants showed antibody to Nipah virus (P = 0.05). All antibody-positive workers were from abattoirs in the three states that reported outbreak cases among pig farmers. Workers in these three states were more likely than those in other states to have Nipah antibody (7/144 [4.86%] versus 0/291 [0%], P < 0.001) and report symptoms suggestive of Nipah disease in pigs admitted to the abattoirs (P = 0.001).

CONCLUSIONS

Nipah infection was not widespread among abattoir workers in Malaysia and was linked to exposure to pigs. Since it may be difficult to identify Nipah-infected pigs capable of transmitting virus by clinical symptoms, using personal protective equipment, conducting surveillance for Nipah infection on pig farms which supply abattoirs, and avoiding handling and processing of potentially infected pigs are presently the best strategies to prevent transmission of Nipah virus in abattoirs.

Antigen binding characteristics of antibodies induced against nitric oxide modified plasmid DNA

Nitric oxide (NO) generated by the reduction of sodium nitrite with sodium dithionite caused damage to plasmid Bluescript DNA leading to strand breaks and base modifications. The NO-plasmid DNA was highly immunogenic in rabbits. The antibody activity was inhibited to the extent of 86% with the immunogen as inhibitor, indicating the induction of immunogen specific antibodies. However, delineating the antigenic specificity of anti-NO-plasmid DNA antibodies by competition ELISA, multiple cross-reactivity was observed. The antibodies recognised B-, A- and allied conformations. The visual detection of immune complex formation with native and NO-plasmid DNA reiterated preferential binding with modified plasmid DNA. DNA modified by nitric oxide presents unique epitopes which may be one of the factors in antigen-driven autoimmune response in systemic lupus erythematosus.

Emergency medicine in China: redefining a specialty

The People's Republic of China (PRC) is developing a unique system of emergency medical facilities based on its own conditions, adapting elements of both North American and European models, as well as creating some of its own. This ongoing evolution of a system for provision of emergency medical care reflects a society that is itself in rapid transition. There have been great strides in the advancement of this specialty over the last two decades. China now has an Emergency Medicine (EM) association, training programs, and specialty journals. Nevertheless, although an organizational framework now exists, development of EM in China as a whole can be said to be at an early stage. The number of trained practitioners is still small, and EMS providers are generally not trained or integrated except in a few large cities. By all estimates, the pace of growth of EM in China will continue to accelerate as China's economy and demographics approach those of the west, but the final form they will take is still uncertain.

Identification of Candida tropicalis HSR1, a gene of the heat-shock factor-related family, which confers salt tolerance in Saccharomyces cerevisiae

A genomic library of Candida tropicalis in a yeast multicopy plasmid has been screened for clones conferring salt tolerance upon transformation into S. cerevisiae. The best halotolerance clone contained an open reading frame encoding a predicted protein of 728 amino acids with homology to transcription factors of the heat-shock family. This novel gene was named HSR1 and is present in single copy in the C. tropicalis genome. Upon transformation into S. cerevisiae it increases the expression of ENA1, a major determinant of salt tolerance encoding a cation-extrusion pump. The sequence of CtHSR1 has been deposited in the EMBL data library under Accession No. AJ296093.

Cochrane Drugs and Alcohol Group: the development of systematic reviews of treatment outcome

- The aim of the Cochrane Collaboration is to promote review processes which address all aspects of health care and which can be viewed by clinicians to guide their day-to-day clinical practice. Recently, a Cochrane review group on drugs and alcohol has been developed. The Cochrane Review Group Editorial base is in Rome, Italy. There is an international editorial board with editors in the UK, Italy, France, Australia and the USA. So far, the group has published five reviews addressing treatment for opioid, cocaine and alcohol dependence. Additional reviews and protocols are in progress. A growing number of titles are registered with the group. Interested readers and potential reviewers and/or referees can contact the Cochrane Drugs and Alcohol Group Coordinator in Rome at the e-mail address: dacochrane@asplazio.it

Hyperalgesic responses in methadone maintenance patients

Opioid substitution treatment for dependence may alter sensitivity to pain. Previous studies on pain sensitivity in methadone maintenance patients have yielded contradictory results. This study compared nociceptive responses between 16 patients on stable, once daily, doses of methadone and 16 matched control subjects. Two types of nociceptive stimuli were used: (1) electrical stimulation; and (2) a cold pressor test. Two parameters were measured: detection for onset of pain, and pain tolerance. Methadone patients were tested over an inter-dosing period: at the time of trough plasma methadone concentration (0 h), and 3 h after their daily dose. Control subjects were tested twice 3 h apart. Blood samples were collected to determine plasma methadone concentration. In methadone patients, trough to peak increases in mean R-(-)- and S-(+)-methadone concentrations (118 and 138 ng/ml to 185 and 259 ng/ml, respectively) resulted in significant increases in pain detection and tolerance values for both nociceptive stimuli. Using electrical stimulation, methadone patients' pain tolerance values were lower than controls at 0 h, but higher than controls at 3 h; no significant differences in pain detection values were found. For the cold pressor test, methadone patients detected pain significantly earlier than controls at 0 h, and were also substantially less pain tolerant than controls at both 0 and 3 h. There were no significant differences in pain detection values between the two groups at 3 h. Pain tolerance to pain detection ratios for methadone patients were significantly lower than controls for the cold pressor test at 0 and 3 h, and for electrical stimulation at 0 h only. In summary, the relative pain sensitivity of methadone maintenance patients is determined by the nature of the nociceptive stimulus (e.g. cold pressor test versus electrical stimulation), the plasma methadone concentration (trough versus peak plasma concentration), and whether thresholds are determined for detection of pain or pain tolerance. Although responding to changes in plasma methadone concentration, maintenance patients are markedly hyperalgesic to pain induced by the cold pressor test.

Interaction of nutrition and binge ethanol treatment on brain damage and withdrawal

To determine if nutrition plays a role in ethanol withdrawal and alcohol-induced brain damage, the effects of a 4-day ethanol binge treatment using ethanol in a nutritionally complete liquid diet compared to ethanol mixed with water were studied. The nutritionally complete diet group (ETOH-diet) received a complete diet of sugars, proteins and fats with vitamins and minerals with approximately 53% of calories from ethanol while the nutritionally deprived group (ETOH-H2O) received 100% of calories from ethanol. No difference in withdrawal behavior was found between the ETOH-diet and ETOH-H2O groups during the 72-hour period studied. In addition, no difference was seen for serum levels of magnesium and zinc taken at last dose or following 72 h of withdrawal. Serum alanine aminotransferase (ALT) and ammonia were increased in both groups with ETOH-diet showing a greater increase in ALT than ETOH-H2O. Both groups showed damage in the olfactory bulb, perirhinal, agranular insular, piriform and lateral entorhinal cortical areas as well as hippocampal dentate gyrus and CA-3. Interestingly, the ETOH-diet group displayed more damage at last dose in the posterior dentate and CA-3 of hippocampus than did the ETOH-H2O group. This study suggests that nutritional components and total caloric intake do not effect behavior during ethanol withdrawal and that a nutritionally complete diet may increase ethanol-induced brain damage.

Appropriateness of laboratory testing in nursing home elderly with advanced dementia: an opinion poll among physicians

OBJECTIVE

Dilemmas regarding selection of appropriate laboratory tests in older frail nursing home patients with advanced dementia are commonly encountered by physicians. Our objective was to study physician opinions about evaluating the appropriateness of laboratory testing in older hospitalized patients in nursing homes based on a real case.

SETTING

A 750-bed university teaching hospital in the Bronx that regularly receives acutely ill older residents from long-term care facilities, with medical care provided by residents, fellows, and teaching faculty.

DESIGN

An opinion poll was conducted among 53 physicians. Information was provided on the history, physical examination, and laboratory findings of a 92-year-old woman with advanced Alzheimer's dementia admitted for gastrointestinal bleeding to the acute care Geriatrics unit. A questionnaire sought opinions on selection of laboratory tests (emphasizing Troponin I) and management in this patient. Chi-square analysis was performed to analyze the data

RESULTS

The majority of polled physicians (37/53, P = 0.01) felt that ordering Troponin I in the setting described hindered patient care and stated they would not have ordered the test. The opinion on overall management was divided (P = 0.861).

CONCLUSION

Dilemmas regarding choosing appropriate laboratory tests, including their implications for care, are found frequently in the setting of frail, demented elderly from nursing homes hospitalized for acute care. We suggest that the choice of tests in these subjects with advanced dementia be individualized based on due consideration for life expectancy, quality of life, and surrogate opinion.

The impact of cannabis decriminalisation in Australia and the United States

This paper summarises and compares the impacts of cannabis decriminalisation measures in two countries. In Australia, an expiation model of decriminalisation succeeded in avoiding the imposition of criminal convictions for many offenders, but substantial numbers of offenders received criminal convictions because of a general "net-widening" in cannabis offence detections, and the failure of many offenders to pay expiation fees and thus avoid criminal prosecution. Despite these problems, the expiation approach has been cost-effective, reducing enforcement costs without leading to increased cannabis use. In the United States, cannabis decriminalisation similarly reduced enforcement costs, with enforcement resources generally redirected toward trafficking and other illicit drugs. There were no increases in cannabis use or substantial problems that could be ascribed to decriminalisation. The implications for other countries are discussed, with particular attention to the importance of implementation issues, monitoring, and evaluation. Although decriminalisation has succeeded in reducing enforcement and other costs without increasing the problems associated with cannabis use, the same impacts would not necessarily result from the legalisation of cannabis or the decriminalisation of other illicit drugs.

Glucocorticoids enhance the expression of the basolateral Na+:HCO3- cotransporter in renal proximal tubules

BACKGROUND

Studies have shown that glucocorticoids enhance HCO3- reabsorption in proximal tubules. Functional and molecular studies indicate that HCO3- reabsorption in proximal tubules is mediated via luminal H(+)-ATPase and Na+/H+ exchanger (NHE-3), and basolateral Na+:HCO3- cotransporter (NBC) acting in series. The purpose of these experiments was to examine the effect of adrenal steroids on NBC-1 and NHE-3 expression and activity in rat renal proximal tubules.

METHODS

Rats were injected subcutaneously with dexamethasone (100 mu/day) or deoxycorticosterone acetate (30 mg/kg), potent glucocorticoid, or mineralocorticoid analogues, respectively. Animals were sacrificed after two or four days, and NBC-1 and NHE-3 mRNA expression and activities were measured in cortex and proximal tubules.

RESULTS

Northern hybridizations indicated that cortical NBC-1 mRNA expression increased by approximately 92% in rats treated with dexamethasone for four days (N = 6, P < 0.03) but not two days. NHE-3 mRNA expression remained unchanged. NBC and NHE-3 activities were measured as the Na-dependent pHi recovery from an acid load in the presence or absence of HCO3-, respectively, and appropriate inhibitors in proximal tubule suspensions loaded with BCECF. NBC activity increased by approximately 80% in rats treated with dexamethasone for four days (P < 0.01, N = 5) but not two days. NHE-3 activity increased by 34 and 42% in rats treated with dexamethasone for two and four days, respectively (P < 0.05 and P < 0.02 for each group vs. control). Treatment with deoxycorticosterone acetate did not alter NBC-1 expression.

CONCLUSION

Glucocorticoids at pharmacologic concentrations enhance the mRNA expression and functional activity of renal proximal tubule NBC-1. Enhanced NBC and NHE-3 activities could result in increased HCO3- reabsorption in proximal tubule and could contribute to the maintenance of metabolic alkalosis in pathophysiologic states associated with increased glucocorticoid production.

Antigen binding characteristics of antibodies against hydroxyl radical modified thymidine monophosphate

Reactive oxygen species (ROS) are formed in living organisms during normal metabolic reactions as well as under different environmental stresses. In this study, thymidine monophosphate (TMP) was exposed to hydroxyl radical (OH) and challenged in rabbits. TMP and OH-modified TMP were found to be nonimmunogenic. The TMP was linked to bovine serum albumin (BSA) by carbodiimide reaction, and then modified with the OH. The neoantigens, TMP-BSA, and ROS-TMP-BSA conjugates induced highly specific antibodies against immunogens. Induced antibodies exhibited appreciable cross-reactivity with various polynucleotides and nucleic acids. In this respect, the induced antibodies resembled the diverse antigen-binding characteristics of naturally occurring systemic lupus erythematosus (SLE) anti-DNA autoantibodies.

A review of biological indicators of illicit drug use, practical considerations and clinical usefulness

AIMS

To examine a range of biological indicators of illicit drug use, including blood, urine, hair and saliva, addressing both technological and practical issues relating to their application and interpretation.

METHODS

The review process involved an examination of key reference texts and literature from the scientific fields of analytical and clinical toxicology.

FINDINGS

Urine remains the biological tool of choice for qualitative detection of illicit drug use in a clinical setting, while quantitative accuracy remains strictly the domain of blood. The growing sophistication of laboratory analysis may additionally make possible the routine use of hair sampling which can provide a much longer time frame for assessment. Breath, saliva, sweat or breast milk remain possibilities in the future.

CONCLUSIONS

Accurate interpretation of the screening tests within a clinical setting alongside other relevant information remains the key to the usefulness of any test.

The aging paradox: free radical theory of aging

There are more than 300 theories to explain the aging phenomenon. Many of them originate from the study of changes that accumulate with time. Among all the theories, the free radical theory of aging, postulated first by Harman, is the most popular and widely tested, and is based on the chemical nature and ubiquitous presence of free radicals. This review aims to recapitulate various studies on the role of free radicals in DNA damage-both nuclear as well as mitochondrial-the oxidative stress they impose on cells, the role of antioxidants, the presence of autoantibodies, and their overall impact on the aging process.

Human anti-DNA autoantibodies and induced antibodies against ROS-modified-DNA show similar antigenic binding characteristics

Alterations in DNA structure by hydroxyl radical modification was characterized by UV spectroscopy, Tm, nuclease S1 digestibility and base modification. In view of indicted role of oxygen free radicals in human diseases, an attempt has been made to precisely compare the antigen binding properties of induced antibodies against hydroxyl radical modified DNA with those of naturally occurring anti-DNA autoantibodies. Antibodies induced against ROS-DNA showed diverse antigen binding characteristics which were comparable with those derived from SLE patients. The immune IgG recognized native DNA, heat denatured DNA, and synthetic polynucleotides in B-/B-like conformations. IgG isolated from SLE sera showed preference for ROS-DNA in competition-inhibition assay. The antigenic diversity of induced antibodies and preference of circulating anti-DNA autoantibodies for ROS-DNA over that of native DNA demonstrates the possible role of modified DNA antigens in the pathogenesis of SLE.

Antigen binding characteristics of experimentally-induced antibodies against hydroxyl radical modified native DNA

Hydroxyl radical, generated by UV irradiation of hydrogen peroxide caused damage to native calf thymus DNA leading to strand breaks, base modification and decrease in melting temperature. The ROS-DNA was highly immunogenic in goat. The antibody activity was inhibited to the extent of 89% with the immunogen as inhibitor. Antigenic specificity of anti-ROS-DNA antibodies by competition ELISA showed multiple cross-reactivity, recognizing B-, A- and allied conformations. The immune complex formation with native and ROS-DNA was substantiated by band shift assay. A striking observation, is the enhanced recognition of ROS-thymine and ROS-poly(dT) by the induced antibodies. These investigations suggest that ROS might be the plausible candidate for the presentation of unique epitopes on ROS-DNA, in particular of thymine, inducing antibodies cross-reacting with native DNA and play an important role in the pathogenesis of SLE.

A strategy for reducing maternal mortality

A confidential system of enquiry into maternal mortality was introduced in Malaysia in 1991. The methods used and the findings obtained up to 1994 are reported below and an outline is given of the resulting recommendations and actions.

Correlates of retention on the South Australian Methadone Program 1981-91

OBJECTIVES

To investigate correlates of retention on the South Australian Methadone Program during 1981-91.

DESIGN

Retrospective study of a nonstratified random sample of 229 HIV-negative clients who received methadone between January 1981 and June 1991. Data were collected from clinical records of the 229 HIV-negative clients and also from the 40 clients known to be infected with HIV during the decade.

RESULTS

Being HIV positive, receiving larger maximum doses of methadone, receiving methadone from a private pharmacy and enrolling later in the decade were all associated with longer retention times on the program.

CONCLUSIONS

This study supports the findings of previous studies, that maximum dose of methadone is crucial to retention in methadone programs, But even allowing for maximum dose, obtaining methadone from a private pharmacy was also strongly associated with retention on the program. The more 'humane' clinic policy later in the decade is likely to have increased retention and reduced illicit drug use also.

Immunochemical detection of oxidative DNA damage in cancer and aging using anti-reactive oxygen species modified DNA monoclonal antibody

The formation of reactive oxygen species (ROS), although a normal cellular activity, is considerably enhanced under chronic inflammatory conditions and ischemia. These species have been implicated in various disorders, mutagenesis, carcinogenesis and aging. Of many macromolecules, DNA is the most susceptible to hydroxyl radical, the most reactive of the ROS. The present study is designed to detect oxidative DNA damage in cancer patients and healthy aged humans using an anti-ROS-DNA monoclonal antibody (mAb). Purified calf thymus DNA fragments (approximate size 400 bp) were modified with OH, generated by UV-irradiation (254 nm) of hydrogen peroxide. ROS-modified DNA was characterized by UV-spectroscopy, melting temperature, alkaline sucrose density gradient ultracentrifugation and ion-exchange chromatography. ROS-DNA showed single strand breaks, decrease in Tm, modification of thymine (58.3%) and guanine (20%). The mAb generated against ROS-DNA was characterized for antigen binding specificity by competition ELISA. Monoclonal antibody showed strong binding to ROS-modified DNA, its modified fragments, polynucleotides and bases. With the exception of native DNA, binding of unmodified polynucleotides and bases was much lower. The mAb distinctly recognized DNA samples from lymphocytes of healthy aged humans and gave maximum inhibitions of 49, 53, 64 and 70%, while not reacting with DNA from young population. Similarly, oxidative lesions in DNA from cancer patients were also efficiently recognized by the mAb. DNA from healthy controls served as negative control. The studies demonstrate that the mAb, although cross-reactive, preferentially binds ROS-modified epitopes on DNA. High reactivity of mAb to DNA samples from cancer patients and healthy aged humans indicates increased oxidative stress leading to DNA damage.

Binding of human anti-DNA autoantibodies to reactive oxygen species modified-DNA and probing oxidative DNA damage in cancer using monoclonal antibody

The binding of native and reactive oxygen species-modified DNA (ROS-DNA) to circulating antibodies in the serum of patients with various types of cancer has been investigated by competition enzyme-linked immunosorbent assay. Fifteen sera of 35 showed reactivity with native and/or ROS-DNA. Eleven of these showed higher binding to ROS-DNA (36-64% inhibition), whereas 1 showed higher reactivity with native DNA (nDNA) (42% inhibition). Three sera reacted with both native and ROS-DNA almost equally. Oxidative lesions in human genomic DNA were immunochemically detected using an anti-ROS-DNA monoclonal antibody (MAb) probe. Two of 3 DNA isolates from blood of breast cancer patients, 1 of 3 from lung cancer and 1 of 2 each from hepatocellular cancer and cancer of the gallbladder were reactive with the MAb. Higher recognition of ROS-DNA by circulating antibodies and DNA isolated from cancer patients by the MAb indicates increased oxidative stress leading to DNA damage. Our results suggest that ROS modification of DNA probably alters its immunogenicity leading to the generation of antibodies to ROS-DNA, probably by the activation of autoreactive cells. The induced antibodies against modified DNA are cross-reactive to native DNA.