Safe biotechnology 9: values in risk assessment for the environmental application of microorganisms. The Safety in Biotechnology Working Party of the European Federation of Biotechnology

Risk assessment for the deliberate release of microorganisms into the environment is traditionally carried out on a case-by-case basis. In a similar approach to that used when assessing human pathogenicity, we propose an alternative approach by introducing risk classes to facilitate or complement this type of risk assessment. These consider several sets of scenarios that address the different values that need to be protected. Examples of this approach include risk-class definitions for soil fertility and biodiversity.

The role of microsomal triglyceride transfer protein and dietary cholesterol in chylomicron production in diabetes

AIMS/HYPOTHESIS

The aim of this study was to examine factors involved in chylomicron production in the streptozotocin diabetic rat, our hypothesis being that the synthesis of the chylomicron is abnormal in diabetes.

METHODS

Diabetic rats (n = 20) were paired with control rats (n = 20). Cholesterol emulsion was given by gavage and the lymph duct was cannulated. Lymph was collected for 4 h. Chylomicrons were prepared from the lymph by ultracentrifugation. Lymph apolipoprotein B48 was isolated by gradient gel electrophoresis and quantified by densitometric scanning. Intestinal microsomal triglycerol transfer protein mRNA was measured by solution hybridisation nuclease protection, using a rat specific [32P]-labelled cRNA probe.

RESULTS

Serum triglyceride and cholesterol were greatly increased in diabetic compared with control animals (258 +/- 77 and 8.9 +/- 6.4 mg/ml vs 1.04 +/- 0.37 and 0.54 +/- 0.03 mg/ml, p < 0.0001). Lymph chylomicron triglyceride and cholesterol were also higher in diabetic rats (29.4 +/- 27.3 and 0.28 +/- 0.3 mg/h vs 16.8 +/- 10.6 and 0.18 +/- 0.09 mg/h, p < 0.05). Lymph chylomicron apo B48 was similar in the two groups. Intestinal microsomal triglycerol transfer protein mRNA was higher in the diabetic rats (12.6 +/- 3.2 vs 3.8 +/- 3.0 amol/microgram RNA, p < 0.0001) and there was a positive correlation between lymph triglyceride and microsomal triglycerol transfer protein mRNA in the whole group (r = 0.65, p < 0.01).

CONCLUSION/INTERPRETATION

The study shows that microsomal triglycerol transfer protein mRNA is raised in diabetes without an increase in apolipoprotein B48 in the lymph suggesting that microsomal triglycerol transfer protein regulates chylomicron triglyceride content but not particle number.

Effects of amide local anaesthetics on eicosanoid formation in burned skin

BACKGROUND

Previous studies have demonstrated potent inhibition of burn oedema and progressive ischaemia by local anaesthetics. Since eicosanoids have been suggested to play an important role in the pathophysiology of burns, we compared in the present ex vivo study the effects of topical lidocaine/prilocaine cream (EMLA, ASTRA, Sweden) and intravenous lidocaine with that of saline on eicosanoid formation by normal and burned rat skin.

METHODS

A full-thickness burn trauma was induced in the abdominal skin. All the agents were given 5 min postburn until 2 h after the trauma. The experimental skin was subsequently removed and incubated in Krebs solution for 1 h. Eicosanoid concentrations in the solution were analysed by radioimmunoassay.

RESULTS

EMLA cream induced a significant inhibition of TXB2 (P<0.05) and 6-Keto-PGF1alpha (P<0.01) but not of PGE release from burned skin as compared to saline treatment. Intravenous lidocaine infusions did not significantly influence the release of any of the measured eicosanoids versus saline.

CONCLUSION

In conclusion, the lack of effect of intravenous lidocaine could relate to the severe burn trauma inducing rapid ischaemia which may have interfered with the delivery of the agent to the burned tissues or to insufficient concentrations achieved in the burn area. Topical treatment of burned skin with a local anaesthetic cream significantly reduced the release of TXB2 and 6-Keto-PGF1alpha, suggesting a possible mechanism of action in progressive burn ischaemia.

Interactive effects of subanesthetic ketamine and haloperidol in healthy humans

Ketamine is an N-methyl-D-aspartate (NMDA) receptor antagonist with prominent psychoactive effects in humans. This study evaluated whether the oral administration of haloperidol 5 mg would block the effects of an intravenous ketamine infusion (bolus of 0.26 mg/kg followed by 0.65 mg/kg per hour). Twenty healthy subjects completed 4 test days involving the oral administration of haloperidol or matched placebo 2 h prior to the intravenous infusion of ketamine or saline. Ketamine produced cognitive, behavioral, neuroendocrine, and physiologic effects in the healthy subjects that were similar to previous reports. Haloperidol pretreatment reduced impairments in executive cognitive functions produced by ketamine as measured by proverb interpretations and the Wisconsin Card Sorting Test. However, it failed to block the capacity of ketamine to produce psychosis, perceptual changes, negative symptoms, or euphoria in healthy subjects. These data outline an important, but functionally delineated modulation of ketamine effects by dopamine2 receptors and other sites of haloperidol action.

Patients with primary osteoarthritis show no change with ageing in the number of osteogenic precursors

The variation in marrow colony forming unit-fibroblastic (CFU-F) number in 59 patients (14-87 years of age) undergoing corrective surgery (14 controls; 14-48 years of age) or hip arthroplasty for primary osteoarthritis (45 OA; 46-87 years of age) was examined to determine whether marrow CFU-F, derived from marrow stromal fibroblastic stem cells, are maintained with the development of primary osteoarthritis (OA). Total colony number, colony size as well as alkaline phosphatase-positive colonies were determined. The mean fibroblast colony forming efficiency from the whole patient group was 2.4 x 10(-5) +/- 1.4 x 10(-5). Ageing had no effect on the colony forming efficiency or on the alkaline-phosphatase-positive colony forming efficiency, irrespective of gender. Thus precursor cells with the potential for osteogenic differentiation are maintained in OA with ageing. However, colony size showed a significant reduction with age, implying altered proliferation potential of osteogenic progenitors with ageing. This ageing effect may not be as significant in OA as in the rest of the population as bone mineral density is often preserved in osteoarthritis. As there is no apparent deficit in primitive progenitor cells, this preservation may be the result of altered regulation of osteoprogenitor activity in OA.

HIV risk behavioral surveillance: a methodology for monitoring behavioral trends

OBJECTIVE

This article summarizes issues and recommendations for conducting HIV risk behavioral surveillance surveys (BSS) based on experiences from ten BSS projects in eight countries in Asia and Africa.

BACKGROUND

BSS consists of systematic and repeated cross-sectional surveys of HIV and sexually transmitted disease-related behaviors, with other knowledge and attitudinal variables added where appropriate. Its major purpose and utility is in detecting trends among selected vulnerable and high-risk population groups whose behavioral change can have the most impact on the epidemic. BSS is also useful for tracking trends in behaviors over time in regions exposed to HIV prevention activities, as a contributing component to the comprehensive monitoring and evaluation of interventions.

RECOMMENDATIONS

(i) implement BSS as an essential adjunct to HIV/STD epidemiological surveillance; (ii) use BSS for evaluation purposes in combination with process data and triangulate results with qualitative research; (iii) choose sentinel groups based on epidemiological considerations, evaluation and monitoring needs, representative sampling frames, and political and cultural considerations; (iv) maintain 1-year intervals between survey waves for most groups in order to provide yearly updates on behavioral trends for programmatic adjustments; (v) use internationally standardized indicators and question wording; (vi) maintain strict quality control standards to enhance data validity and reliability; and (vii) develop a clear dissemination strategy during BSS design to increase the likelihood of utilization of BSS results.

CONCLUSION

BSS represents a cost-effective way to determine whether programmatic behavioral targets and goals are being met, to identify persisting risk behaviors over time, and to indicate whether new intervention approaches are necessary.

Genetic and environmental factors affecting bone mineral density in large families

This study assessed whether relatives with low bone mineral density (BMD) could be identified in five large families using historical, biochemical, and genetic markers for osteoporosis. Fifty of 65 relatives had their bone density and bone turnover markers measured, together with an assessment of their risk factors for osteoporosis. Only 33% (5/15) of siblings, 50% (6/12) of children and 43% (10/23) of nephews and nieces had entirely normal BMD. There was no difference in life-style risk factors for osteoporosis, history of previous fractures or body mass index between normal subjects and those with osteopenia or osteoporosis. Osteopenic individuals had a significantly higher than normal osteocalcin value. Within families, there was no clear association between BMD and any of the genetic markers (vitamin D receptor gene polymorphisms, COL 1A1 and COL 1A2 polymorphisms of the collagen gene), either alone or in combination. The addition of genetic markers to the other risk factors for low BMD did not improve the prediction of BMD. In conclusion, we suggest that the presence of osteoporosis in a first degree relative should be one of the clinical indications for bone density measurement as the individuals at risk would not be picked up by other methods.

Interactive effects of subanesthetic ketamine and subhypnotic lorazepam in humans

Ketamine is an N-methyl-D-aspartate (NMDA) receptor antagonist with psychotogenic and dissociative effects in healthy humans. These cognitive and perceptual effects in humans are reportedly reduced by benzodiazepine premedication. This study assessed the interactive effects of a ketamine (i.v. bolus of 0.26 mg/kg followed by an infusion of 0.65 mg/kg per hour) and lorazepam 2 mg., PO, in humans. Twenty-three healthy subjects completed 4 test days involving the oral administration of lorazepam or matched placebo 2 h prior to the i.v. infusion of ketamine or placebo. Ketamine: 1) produced behaviors similar to the positive and negative symptoms of schizophrenia as assessed by the Brief Psychiatric Rating Scale (BPRS); 2) evoked perceptual alterations as measured by the Clinician-Administered Dissociative States Scale (CADSS); 3) impaired performance on the Wisconsin Card Sorting Test (WCST) and other tests sensitive to frontal cortical impairment; and 4) had amnestic effects. Lorazepam produced attention impairments, concrete proverb interpretations, and recall impairments. Lorazepam reduced ketamine-associated emotional distress and there was a non-significant trend for it to decrease perceptual alterations produced by ketamine. However, it failed to reduce many cognitive and behavioral effects of ketamine, including psychosis. Further, lorazepam exacerbated the sedative, attention-impairing, and amnestic effects of ketamine. There was no evidence of pharmacokinetic interaction between these medications. These data suggest that subhypnotic lorazepam and ketamine show a spectrum of interactive effects, ranging from antagonism to potentiation.

Comparison of SSCP analysis and CFLP analysis for mutation detection in the human iduronate 2-sulfatase gene

Scanning methodologies are used for the identification of DNA fragments that differ from the normal nucleotide sequence. Fragments that produce abnormal band patterns are sequenced for characterization of the exact mutation. Factors considered in choosing a scanning methodology include reproducibility, sensitivity, and time. In the present study, we compared single-stranded conformational polymorphism (SSCP) and Cleavase fragment length polymorphism (CFLP) methodologies for mutation scanning of exon VIII in the iduronate 2-sulfatase (IDS) gene. Mutations of the IDS gene result in an X-linked lysosomal storage disease, Hunter syndrome. These six known mutations analyzed by the two methods included a one base pair deletion, a one base pair insertion, and four point mutations. SSCP analysis detected all of the mutations and CFLP analysis detected three of the six mutations. We concluded that SSCP analysis was preferable to CFLP analysis for scanning exon VIII in the IDS gene for mutations.

HIV risk behavioral surveillance in Bangkok, Thailand: sexual behavior trends among eight population groups

OBJECTIVE

To assess trends in HIV risk behaviors over a 3-year period in eight population groups in Bangkok, Thailand.

DESIGN AND SUBJECTS

Using a repeated cross-sectional survey design with a structured questionnaire, we collected five sets of self-reported sexual behavior data related to HIV risk from the following subject groups at the same sampling sites during 1993-1996: direct and indirect female sex workers, male attenders of sexually transmitted disease (STD) clinics, female attenders of antenatal care clinics, male and female vocational students, and male and female factory workers.

RESULTS

Reported patronage of commercial sex by the three male groups declined by an overall average of 48% over the 3-year period. Other non-regular sexual partnerships declined among male STD clinic attenders and vocational students. Condom use during most recent sexual intercourse between sex workers and clients peaked at high levels (>90%) in the early data waves, while among indirect sex workers and their clients, consistent condom usage increased from 56% to 89%. Low condom use persisted among sex workers and their non-paying sex partners. Single women reported low levels of sexual activity and condom use with no signs of an increase. Similarly, married women from antenatal clinics reported low condom use with their husbands, with no change throughout the period of the study.

CONCLUSIONS

HIV risk behavioral surveillance is a useful way of determining whether behavior change has occurred in specific population groups. The results here confirm and add to a growing set of evidence of risk behavior reduction in Thailand. The behavioral changes did not occur uniformly but varied depending on the sexual dyad and the population group under study. Behavioral surveillance should be promoted and its methodologies strengthened in attempts to understand the local dynamics of HIV epidemics.

Men with sexually transmitted diseases in Bangkok: where do they go for treatment and why?

OBJECTIVES

To describe and identify predictors of health-care seeking behavior among men with sexually transmitted diseases (STDs) in Bangkok, Thailand.

DESIGN

Cross-sectional survey.

METHODS

Men presenting with STDs were recruited from government clinics (n = 101), private clinics (n = 50) and pharmacies (n = 62). They completed interviewer-administered questionnaires on risk behavior, patterns of treatment-seeking for current and past STDs and attitudes toward health care.

RESULTS

Two-thirds of all subjects had had a previous STD. Approximately one-half believed a partner other than a sex worker was the source of their current infection. Of the sample, 39% of men seen initially at drugstores, 29% at private clinics and 19% at government clinics sought subsequent treatment; failure to respond to therapy was the primary reason for seeking additional care. Men attending drugstores were likely to be younger, have less education and income, and to practice riskier sexual behavior. Patients at drugstores and general private clinics received the least amount of counseling or STD testing, while those attending specialized private STD clinics received the most comprehensive services. Attitudes towards government clinics were uniformly positive regardless of the site of enrollment; conversely, about 50% of clients at drugstores felt that the advice and treatment they received were inadequate. Convenience, affordability and lack of embarrassment were associated with choice of treatment site.

CONCLUSIONS

STD/HIV control in Thailand must focus on improved treatment and counseling at the point of first encounter in the health-care system, particularly in the private sector. Men may be dissuaded from attending government clinics because of lack of convenience. Syndromic case management, incorporation of STD care at other public clinics and the recognition that more men practice unsafe sex with partners other than sex workers could improve STD control.

Safe biotechnology. 8. Transport of infectious and biological materials. Working Party "Safety in Biotechnology" of the European Federation of Biotechnology

The transport of infectious and biological material is regulated by a number of international organizations. This mini-review has been compiled to increase awareness within the scientific community of problems caused by differences in terminology (such as infectious materials/substances, biological products, diagnostic specimens, genetically modified microorganisms) and certain technical aspects of the main international guidelines, and to assist policy makers in the creation of harmonized guidelines. A list of relevant Internet resources has been compiled.

Cytosolic phospholipase A2, cyclo-oxygenases and arachidonate in human stomach tumours

Human stomach tumours usually form more prostaglandins (PGs) than their associated normal mucosa/submucosa, but the mechanisms are not fully understood. The key enzymes are cytosolic phospholipase A2 (cPLA2, Mr 85,000) and the cyclo-oxygenases (COXs) which exist in constitutive (COX-1) and inducible forms (COX-2). In human stomach tumours and associated macroscopically normal tissues, we determined the fatty acid composition by gas chromatography, amounts of cPLA2, COX-1 and COX-2 by immunoblotting with specific antibodies and cPLA2 enzyme activity using a tritiated substrate. Although compared to normal mucosa there was less arachidonate in tumours (P < 0.05), the arachidonate/total fatty acid ratio was higher. Mean amounts of cPLA2 and COX-1 and cPLA2 activity were similar in tumours and normal mucosa. However, substantial amounts of COX-2 were found in the tumours but not in the mucosa, which may explain why many gastric tumours form increased amounts of PGs.

Apolipoprotein E epsilon4 associated with chronic traumatic brain injury in boxing

CONTEXT

Given the similarities between Alzheimer disease and dementia pugilistica, we evaluated the relationship between apolipoprotein E (APOE) genotype and chronic traumatic brain injury (CTBI) in boxers to determine whether there is a genetic susceptibility to the effects of head trauma.

OBJECTIVE

To assess the relationship between CTBI and APOE genotype in boxers.

DESIGN AND SETTING

Clinical characterization of 24 volunteer and 6 referred boxers in an outpatient setting.

PARTICIPANTS

Thirty professional boxers aged 23 to 76 years underwent neurologic and behavioral assessment in conjunction with APOE genotyping.

MAIN OUTCOME MEASURES

Apolipoprotein E genotype was examined in relationship to measures of CTBI. A 10-point clinical rating scale (0-9), the Chronic Brain Injury (CBI) scale, was devised to assess the severity of traumatic encephalopathy associated with boxing. Boxers with abnormal CTBI scores were further classified on the basis of whether their impairments were possibly or probably related to boxing. Scores were analyzed in relation to boxing exposure (number of bouts) and APOE genotype.

RESULTS

Among the 30 boxers, 11 were found to be normal (CBI score=0), 12 showed mild deficits (CBI score=1-2), 4 were moderately impaired (CBI score=3-4), and 3 showed signs of severe impairment (CBI score > 4). High-exposure boxers (ie, those with > or = 12 professional bouts) had significantly higher CBI scores (mean [SD], 2.6 [1.9]) than low-exposure boxers (mean [SD], 0.3 [0.7]) (P<.001), indicating that neurologic impairment as measured by the CBI scale seems related to boxing exposure. The APOE genotype frequencies of the study population were approximately the same as those found in the general population. Boxers with low exposure had mean CBI scores of 0.33, irrespective of APOE genotype. However, high-exposure boxers with an APOE epsilon4 allele had significantly greater CBI scores (mean [SD], 3.9 [2.3]) than high-exposure boxers without APOE epsilon4 (mean [SD], 1.8 [1.2]) (P=.04). All boxers with severe impairment possessed at least 1 APOE epsilon4 allele. The tendency for greater CTBI among those with both high exposure and an epsilon4 allele was statistically significant at the P<.001 level.

CONCLUSIONS

These preliminary findings suggest that possession of an APOE epsilon4 allele may be associated with increased severity of chronic neurologic deficits in high-exposure boxers.

Identification and enrichment of human osteoprogenitor cells by using differentiation stage-specific monoclonal antibodies

A major problem in developmental bone biology is the inability to clearly identify early progenitor cells of the osteogenic and related lineages. Identification of these cells is important for the study of their normal development and for determination of potential changes in skeletal diseases. The objective of the present study was to obtain specific markers for early progenitor cells. Monoclonal antibodies were raised against human marrow stromal fibroblastic cell cultures, known to be rich in progenitors for the stromal lineages. Antibodies were selected initially by their reactivity with these marrow cultures and their immunohistochemical localization in human fetal tissues, in progenitor cell regions adjacent to osteoblastic cells. Antibody HOP-26 was strongly reactive with cells in marrow stromal colonies at early stages of differentiation, before the induction of alkaline phosphatase activity, and decreased dramatically after the cells reached confluence. In sections of human fetal limb, binding of HOP-26 was restricted to cells in close proximity to the developing bone, in periosteum, and between the developing bone trabeculae. In adult trabecular bone tissue, HOP-26 was reactive with occasional cells present within the marrow spaces with osteoblasts, adipocytes, and fibrous tissue unreactive. No antibody binding was detected in sections of skin, muscle, appendix, brain, tonsil, or liposarcoma, or cultured SaOS II, MG63, or skin cells. In primary cell suspensions, HOP-26 was unreactive with blood cells but strongly reactive with 0.59 +/- 0.27% of nucleated marrow cells. The antigen associated with these cells was detectable both intracellularly and on the cell surface, and by using immunopanning, HOP-26 selected the marrow stromal fibroblastic colony-forming units (CFU-F). HOP-26 provides the means to identify osteogenic progenitor cells directly and with high specificity. The present studies demonstrate the value of this antibody in providing enriched populations of progenitor cells for experimental studies of osteogenic differentiation and in histopathology.

The Mattis Dementia Rating Scale in nursing home octogenarians and nonagenarians: effects of age and education

Despite their increasing representation in the population, little is known about the neuropsychological test performance of the oldest old, particularly those who live in residential settings. Limited published data and clinical experience suggest that this group is more likely to perform in the impaired range on standardized tests when cut-offs developed with younger groups are used. We examined the Dementia Rating Scale (DRS) performance of 82 nondemented nursing home residents, aged 80 to 99, with a mean education level of 11 years. Using published norms and cutoffs, a large percentage of this sample performed in the impaired range, particularly on the initiation and conceptualization subtests and on the total score. Education, but not age, was significantly related to performance in this sample. Percentages of patients misclassified were substantial in all groups, but were higher in those with less than 13 years of education. Using a lower total-score cutoff of 110 reduced the percentage of misclassifications markedly. We recommend the development and use of revised cutoff scores for the evaluation of very elderly nursing home residents.

Chronic fatigue syndrome/myalgic encephalomyelitis as a twentieth-century disease: analytic challenges

The challenges of chronic fatigue syndrome (often called myalgic encephalomyelitis, especially in the UK) (CFS/ME) to analytical and medical approaches are connected with our inability to understand its distressing somatic symptoms in terms of a single identifiable and understandable disease entity. The evidence for the roles of viral aetiologies remains inconclusive, as does our understanding of the involvement of the immune system. The history and social context of CFS/ME, and its relation to neurasthenia and psychasthenia are sketched. A symbolic attitude to the condition may need to be rooted in an awareness of psychoid levels of operation, and the expression and spread of CFS/ME may sometimes be aided by the ravages of projective identification. Psychic denial, sometimes violent, in sufferers (especially children and adolescents) and their families may be important in the aetiology of CFS/ME. We draw out common threads from psychodynamic work with five cases, four showing some symptomatic improvement, analytic discussions of three cases being presented elsewhere in this issue of JAP.

A view of the violence contained in chronic fatigue syndrome

In this paper I ask whether there might be any one particular psychopathology likely to be linked specifically with the physical illness known as chronic fatigue syndrome (CFS) or myalgic encephalomyelitis (ME), and whether CFS/ME aids and abets and "fits' an original mental state. I think the question cannot yet be answered. However it is my hypothesis that in some personality structures the onset of CFS/ ME following a physical illness exacerbates negativity and is an aspect of ordinary depression where there is a lowering of energy levels and a loss of zest for life, or it may reveal the pathological aspect of unresolved rage. Depending on the degree of pathological disturbance, working with and through the rage may or may not result in a resolution of the symptoms of ME. In this paper I consider some of the problems in the transference and countertransference relationship, which make it extremely difficult to separate out reality from phantasy. There is then the further problem of the denial of the psyche by the patient as part of the violence inherent in the illness. One case is presented, an example of ME in a borderline male patient in whom resolution could not be achieved.

The use of monoclonal gene rearrangement for detection of minimal residual disease in acute lymphoblastic leukemia of childhood

Sensitive quantification of minimal residual disease (MRD) using the polymerase chain reaction (PCR) is strongly predictive of outcome in childhood acute lymphoblastic leukemia (ALL), with MRD levels at the end of induction therapy of >10(-3) predicting a poor outcome. Methods for sensitive quantification are, however, complicated and time-consuming. Detection by PCR of monoclonal immunoglobulin heavy chain (IgH) and T cell receptor (TCR) gene rearrangements is simple and can be used in routine laboratories but is non-quantitative and of lower but uncertain sensitivity. The aim of this study was to determine the value of detection of monoclonality in identification of different levels of MRD. We looked for monoclonality in 64 bone marrow aspirates which had been obtained from 31 patients with B lineage ALL at various times during induction therapy and for which levels of MRD had been determined by limiting dilution analysis using patient-specific PCR primers. Detection of monoclonality identified levels of MRD of > or =10(-3) during induction with a sensitivity of 78% and a specificity of 93%. The positive and negative predictive values were 0.86 and 0.88, respectively. The sensitivity of detection of a monoclonal IgH rearrangement was greater than that for the TCRgamma locus during induction as an IgH rearrangement was detected more often than a TCRgamma rearrangement in patients who had both IgH and TCRgamma rearrangement at diagnosis. Detection of monoclonality is therefore a simple and quick test applicable to the majority of patients with ALL and it may be useful in identifying high-risk patients at the end of induction and in identifying relapsing patients later during therapy.

Promoting condom-only brothels through solidarity and support for brothel managers

Brothel workers in Thailand are at high risk of HIV infection but they alone do not have adequate bargaining power to insist on condom use with all clients. Brothel managers, on the other hand, are a source of influence over both clients and their workers and can promote universal condom use in their establishments. To test whether brothel managers in Khon Kaen City would adopt and successfully implement a condom-only policy in their establishments, all 24 brothel managers in Khon Kaen City attended a meeting on the dangers of HIV and benefits of an all-condom policy. Ideas on how to implement the policy were discussed. Follow-up visits were made once a month to brothels to resupply condoms, provide reinforcement and to collect data. All brothel managers approved of the condom-only in principle and are now implementing the policy. Results of the evaluation of condom use and degree of solidarity in these 24 brothels are available for the AIDS prevention programme. However, a condom-only policy in brothels can only succeed if managers and brothel workers show solidarity in rejecting all non-condom using clients. Laws to promote condom use may not be needed if brothels are given the opportunity to implement a condom-only policy using their own resourcefulness and determination.

Comparison of technetium-99m-HMPAO and technetium-99m-ECD cerebral SPECT images in Alzheimer's disease

SPECT has shown increasing promise as a diagnostic tool in Alzheimer's disease (AD). Recently, a new SPECT brain perfusion agent, 99mTc-ethyl cysteinate dimer (99mTc-ECD) has emerged with purported advantages in image quality over the established tracer, 99mTc-hexamethylpropyleneamine oxime (99mTc-HMPAO). This research aimed to compare cerebral images for 99mTc-HMPAO and 99mTc-ECD in discriminating patients with AD from control subjects.

METHODS

Twenty-four AD patients (mean age +/- s.d. = 68.9 +/- 8.2 yr) and 13 healthy subjects (68.4 +/- 8.0 yr) were scanned sequentially with 20 mCi of each tracer using the CERASPECT system within 1 mo. Scanning began on average 11.5 +/- 2.8 min after 99mTc-HMPAO injection and 41.8 +/- 10.1 min after 99mTc-ECD. A ratio, R, was derived of count densities in "typically affected" brain structures (parietal and temporal association cortices) to "unaffected" structures (cerebellum, basal ganglia, thalamus, occipital cortex, and sensorimotor cortex).

RESULTS

Analysis of variance revealed significant interaction between diagnostic group and radiopharmaceutical (F = 4.71; df = 1.35; p = 0.04), with 99mTc-ECD demonstrating better separation of R values between AD patients and control subjects than 99mTc-HMPAO. Receiver operating characteristic (ROC) analysis, revealed no significant difference in the ability of the two tracers to correctly classify AD patients and control subjects. Both tracers showed high diagnostic accuracy (99mTc-ECD: sensitivity = 100%, specificity = 92%; 99mTc-HMPAO: sensitivity = 100%, specificity = 85%).

CONCLUSION

Technetium-99m-ECD shows greater contrast than 99mTc-HMPAO between affected and unaffected brain structures in AD when patients are compared to age-matched control subjects. Both tracers perform equally well in correctly classifying patients and control subjects.

High molecular weight phospholipase A2 and fatty acids in human colon tumours and associated normal tissue

Human colon tumours usually form more prostaglandins (PGs) than associated normal tissues, but the mechanism(s) are not fully understood. We analysed fatty acid compositions, in particular arachidonate, and measured the amount and the activity of high molecular weight cytoplasmic phospholipase A2 (cPLA2) of these tissues. Total lipids extracted from homogenised surgical specimens were transesterified and fatty acids were analysed by gas chromatography. cPLA2 was separated by SDS-PAGE, Western-blotted, immunoblotted using a specific antibody to cPLA2 and semiquantified following enhanced chemiluminescence using a scanning densitometer. cPLA2 biological activity was also assayed using 1-stearoyl, 2-[1-14C]-arachidonyl, L-3-phosphatidylcholine. Compared with normal mucosa/submucosa, there was more total arachidonate in tumours (P < 0.01), and increased levels of cPLA2 occurred in 6 of 17 tumours. In conclusion, the higher amounts of tumour total arachidonate and the sometimes higher levels of cPLA2, might help to explain why some human colon tumours form increased amounts of PGs.

Safe biotechnology. 7. Classification of microorganisms on the basis of hazard. Working Party "Safety in Biotechnology" of the European Federation Biotechnology

The current systems for classifying human pathogens on the basis of hazard are well developed and their basic criteria are in general agreement one with another. Of more importance, the safety practices based on these classifications have generally been successful. They have enabled extensive research activities, medical practice and industrial production to be conducted on an ever-increasing scale, involving dangerous microorganisms (e.g. in vaccine production and treatment of infected patients) with a very low incidence of adverse effects on the workers involved and the general public. Although the EU has adopted a harmonised list of agents in groups 1-4 there is as yet no complete agreement among member states and individual microbiologists. The purpose of this paper is to present a historical survey and to discuss the current processes for identifying and classifying the hazards posed by the use of microorganisms in research and technology. This is essential in the design of appropriate methods of counteracting potential risks.

Effects of D-myo-Inositol-1,2,6-triphosphate on eicosanoid formation in burned skin

D-myo-Inositol-1,2,6-triphosphate (IP3) has been shown to reduce edema and progressive ischemia following experimental skin burns. The mechanism(s) are not identified but could be related to antiinflammatory effects of the agent. In the present ex vivo study we compared the effects of IP3 with those of saline and indomethacin on eicosanoid formation by normal and burned rat skin. In burned skin IP 3 treatment reduced the release of thromboxane B2 (TXB2) (P < 0.01) and leukotriene B4 (LTB 4) (P < 0.05) but there was only a weak trend for less prostaglandin E (PGE) compared to burned control animals receiving saline. Indomethacin reduced the release of TXB2 (P < 0.01), and PGE (P < 0.001), but not LTB 4 from burned skin compared to skin from saline-treated burned animals. In non-burned skin IP 3 increased the release of PGE (P < 0.01) and LTB 4 (P < 0.01), but did not significantly influence TXB2 accumulation in the incubation fluid compared to the saline-treated group. Indomethacin reduced the release of TXB2 (P < 0.001) and PGE (P < 0.001), but increased LTB 4 (P < 0.001) in normal skin compared to the saline-treated group. In conclusion, IP 3 inhibited the release of TXB2 and LTB 4 from burned skin ex vivo, but increased PGE and LTB 4 release from normal skin. These results suggest that the mode of action of IP 3 differs from that of nonsteroidal antiinflammatory drugs. The effects of IP 3 on the arachidonic acid cascade also seem to differ in burned versus normal skin.

Activity of nimesulide on constitutive and inducible cyclooxygenases

Prostaglandins are pro-inflammatory but are gastroprotective. The gastric mucosa synthesizes prostaglandins mainly via constitutive cyclooxygenase (COX-1), whereas leucocytes have inducible enzyme (COX-2). Nimesulide (CAS 51803-78-2) differentially inhibited prostanoid synthesis in these human tissues as well as with in vitro enzyme assays, and was less potent than indometacin (CAS 53-86-1) on COX-1. Fresh human gastric mucosa was cut finely, washed and pre-incubated (100 mg in 1 ml phosphate buffered saline pH 7.4) with or without nimesulide or indometacin (0.1-100 micrograms/ml; 0 degree C; 30 min). The fluid was replaced with fresh identical solution, incubated (37 degrees C; 30 min) and the solution assayed. Isolated leucocytes from human peripheral blood were incubated (1-1.5 x 10(6), 2 ml Krebs' solution) with or without nimesulide or indometacin (0.1-100 micrograms/ml; 37 degrees C; 1 h), stimulated with lipopolysaccharide (5 micrograms/ml), further incubated for 24 h at 37 degrees C and the medium assayed for the prostanoids PGE, TXB2, 6-keto-PGF1 alpha and the leukotriene LTB4 by radioimmunoassay (RIA). In vitro assays with COX-1 from ram seminal vesicles, or COX-2 from sheep placenta, were performed by pre-incubating the enzymes with vehicle alone (controls) or with drug for 5 min at 37 degrees C. Arachidonate (10 mumol/l) was added and further incubated for 2 min at 37 degrees C. Reactions were terminated and PGE determined by RIA. Both drugs caused concentration-related inhibitions of prostanoid accumulation in incubates of both tissues. Nimesulide reduced PGE accumulation more potently in incubates of stimulated leucocytes than of gastric mucosa. With gastric tissue, nimesulide was less potent than indometacin by approximately 6-22 fold (IC50 for PGE, TXB2, 6-keto-PGF1 alpha, respectively; 14.8 vs 2.5; 12.8 vs 1.0; 31.1 vs 1.4 mumol/l; p < 0.05 to 0.02). With the leucocytes, the concentrations of both drugs, particularly indometacin were not low enough to calculate the IC50. With the in vitro assay, nimesulide (0.01 to 100 mumol/l) did not inhibit PGE formation by COX-1 but caused a concentration-related inhibition of PGE formation by COX-2 (4-60%). These results are consistent with the effective analgesic/anti-inflammatory activity of nimesulide coupled with better gastric tolerance compared to indometacin.

The thermal acclimation of burst escape performance in fish: an integrated study of molecular and cellular physiology and organismal performance

Goldfish (Family Cyprinidae, Carassius auratus) and killifish (Family Cyprinodontidae, Fundulus heteroclitus) were acclimated to 10, 20 and 35 &deg;C for 4 weeks. The thermal acclimation of C-start (escape swimming) performance and the physiological properties of fast twitch muscle fibres that underlie it were investigated in these species at the molecular (myosin isoform expression), biochemical (myofibrillar ATPase activity), cellular (contractile kinetics) and organismal levels of organisation. Peptide maps were obtained for fast muscle myosin heavy chains, isolated from 10 &deg;C- and 35 &deg;C-acclimated fish. Different myosin heavy chain isoforms were expressed in response to a change in acclimation temperature in goldfish, but myosin heavy chain isoform expression was unaffected by acclimation temperature in killifish. Compared with fish acclimated to 35 &deg;C, acclimation to 10 &deg;C increased the activity of fast muscle myofibrillar ATPase assayed at 10 &deg;C fivefold in goldfish and only 50 % in killifish. Muscle twitch contraction time at 10 &deg;C decreased significantly in response to acclimation to 10 &deg;C in both species; however, the magnitude of this response was much greater in goldfish (100 %) than in killifish (30 % or less). In goldfish, these changes in the physiological properties of fast twitch fibres during 10 &deg;C acclimation resulted in a six- to eightfold increase in the speed and turning velocity of fish performing C-starts at 10 &deg;C. By comparison, the somewhat smaller acclimatory response of killifish fast muscle properties was accompanied by only a minor (50 % or less) adjustment in locomotor performance. Thermal acclimatory responses of fast muscle at the molecular, biochemical and cellular levels of organisation are clearly reflected in alterations in organismal escape performance.

The effect of folate on the methotrexate/indomethacin interaction in a murine cancer cell line

1. The effect of folate on the interaction between methotrexate (a folate analogue) and indomethacin has been examined in murine NC carcinoma cells. 2. Conditioning of NC cells to a physiological (20 nM) folate concentration after culture in a high folate concentration increased the response to methotrexate. The sensitivity of these conditioned cells to methotrexate related inversely to the folate concentration. 3. At 20 nM and 2 microM folate, indomethacin 1 micrograms ml-1 potentiated the cytotoxicity of methotrexate 4 and 8 ng ml-1 (both P < 0.03). 4. When NC cells were incubated with [3H]-methotrexate at 20 nM and 2 microM folate, there was a trend for increased tritium accumulation with indomethacin 0.36 micrograms ml-1 (1 microM; P < 0.01). 5. We conclude that the folate concentration can affect the sensitivity of NC cells to methotrexate, although the degree of potentiation of cytotoxicity by indomethacin remains similar.

Interaction between methotrexate and indomethacin on a human normal haemopoietic cell line

1. The interaction between methotrexate and indomethacin has been examined, at a physiological folate concentration (20 nM), on a human normal lymphoblast-like cell line (RPMI 1788) in vitro. 2. Indomethacin (1 microgram ml-1) increased the reduction of lymphoblast growth caused by methotrexate (10-80 ng ml-1). 3. Indomethacin (0.1 and 1 microgram ml-1) potentiated the cytotoxicity of methotrexate (20 and 40 ng ml-1) after 4 days in culture. 4. Indomethacin (0.4 micrograms ml-1) reduced the accumulation of tritium in lymphoblasts incubated with [3H]-methotrexate after 30 min; therefore initial drug accumulation was not responsible for the potentiation seen after 4 days. 5. If indomethacin increases the killing of human cancer cells by methotrexate in vivo, with a smaller potentiation on lymphoblasts, this combination may be beneficial in treating human malignancy.

Comparison of invasive and non-invasive measurement of continuous arterial pressure using the Finapres in patients undergoing spinal anaesthesia for lower segment caesarean section

We have compared arterial pressures measured by an indwelling radial cannula with those obtained non-invasively by the Finapres 2000 (Ohmeda) during spinal anaesthesia for lower segment Caesarean section. The digital outputs of both pressures were recorded using a computerized system. We studied 20 patients, yielding a total of 18,772 data points after elimination of data recorded during arterial flushing and erroneous results from each source. The data analysis demonstrated a normal distribution for differences between the two methods of measurement, and the correlations between invasive and Finapres readings for systolic, diastolic and mean pressures were 0.78, 0.72 and 0.79, respectively, indicating an overall poor reflection of intra-arterial pressure by the Finapres under these circumstances. Some patients and some periods of readings reflected a high degree of precision and little bias. However, unexplained large differences in pressure and trends of change that were out of phase over time occurred frequently. We conclude that the Finapres cannot be recommended as a monitor of arterial pressure in this group of patients in whom sudden hypotension may be a threat to maternal or fetal outcome.

IS WALKING COSTLY FOR ANURANS? THE ENERGETIC COST OF WALKING IN THE NORTHERN TOAD BUFO BOREAS HALOPHILUS

Locomotor mode and the maximal capacity for aerobic metabolism are thought to be co-adapted in anuran amphibians. Species that rely heavily on walking often have high capacities for aerobic metabolism relative to species that rely primarily on saltation. We tested the hypothesis of co-adaptation of gait and aerobic metabolism by investigating the locomotor energetics of Bufo boreas halophilus, a toad that walks, but does not hop. Rates of oxygen consumption during locomotion were measured in an enclosed variable-speed treadmill. The steady-state rate of oxygen consumption (V(dot)O2ss) increased linearly within a range of sustainable speeds [V(dot)O2ss (ml O2 g-1 h-1) = 0.93 x speed (km h-1) + 0.28]. The minimum cost of transport, Cmin (the slope of this relationship), varied significantly among individual toads. When expressed in units of oxygen consumed per distance travelled (ml O2 km-1), Cmin scaled isometrically with body mass: Cmin = 0.69mass1.07. Consequently, mass-specific Cmin (ml O2 g-1 km-1) was uncorrelated with body mass. Variation in Cmin was also unrelated to experimental temperature. Mass-specific Cmin estimates were similar to previous allometric predictions for terrestrial animals of similar size, which contrasts with previous findings for another toad species. Maximum rates of oxygen consumption measured in closed, rotating respirometers were significantly higher than the maximum rates achieved on the treadmill, but lower than those measured previously in other Bufo species. Our results indicate that walking is not necessarily a costly gait for toads and that high maximum rates of oxygen consumption are not associated with reliance on walking within the genus Bufo.

Spinal anaesthesia for caesarean section: comparison of infusions of phenylephrine and ephedrine

Maternal cardiovascular changes and neonatal acid-base status were assessed in 29 healthy women undergoing elective lower segment Caesarean section under spinal anaesthesia. The patients were allocated randomly to one of three groups to receive an i.v. infusion of one of the following: ephedrine 1 mg min-1 (group E1: n = 10), ephedrine 2 mg min-1 (group E2: n = 9), or phenylephrine 10 micrograms min-1 (group P: n = 10). Invasive arterial pressure was monitored continuously and if hypotension occurred (defined as a 20% decrease from baseline, taken after i.v. preload administration), bolus doses of either ephedrine (6 mg in groups E1 and E2) or phenylephrine (20 micrograms in group P) were given. Only four patients became hypotensive in group E2, compared with eight patients in group E1 and nine patients in group P. The total time that the patients remained hypotensive was greatest in group P (P < 0.005), less in group E1 and least in group E2. Neonatal Apgar scores and acid-base profiles were similar in all three groups. In this study, an infusion of phenylephrine 10 micrograms min-1 with bolus doses of 20 micrograms was shown to be significantly less effective in maintaining systolic arterial pressure within 20% limits of baseline compared with an infusion of ephedrine 1 or 2 mg min-1 with bolus doses of 6 mg.

Effect of lignocaine on eicosanoid synthesis by pieces of human gastric mucosa

Lignocaine can affect prostaglandin synthesis in various tissues, and it has anti-inflammatory activity. No studies have been made previously on human isolated gut tissues. When concentrations of 5, 50 and 250 micrograms mL-1 lignocaine were incubated with human gastric mucosa/submucosa at 37 degrees C for 30 min, only the highest concentration reduced the levels of prostaglandin E, thromboxane B2 and 6-keto-PGF1 alpha in the incubates, and leukotriene C4/D4 was unaffected. Therapeutically relevant amounts of lignocaine given parenterally would therefore seem unlikely to alter gastric mucosal prostanoids, but high doses can be given orally because of extensive first-pass metabolism in the liver.