Faecal indicator bacteria enumeration in beach sand: a comparison study of extraction methods in medium to coarse sands

AIMS

The absence of standardized methods for quantifying faecal indicator bacteria (FIB) in sand hinders comparison of results across studies. The purpose of the study was to compare methods for extraction of faecal bacteria from sands and recommend a standardized extraction technique.

METHODS AND RESULTS

Twenty-two methods of extracting enterococci and Escherichia coli from sand were evaluated, including multiple permutations of hand shaking, mechanical shaking, blending, sonication, number of rinses, settling time, eluant-to-sand ratio, eluant composition, prefiltration and type of decantation. Tests were performed on sands from California, Florida and Lake Michigan. Most extraction parameters did not significantly affect bacterial enumeration. anova revealed significant effects of eluant composition and blending; with both sodium metaphosphate buffer and blending producing reduced counts.

CONCLUSIONS

The simplest extraction method that produced the highest FIB recoveries consisted of 2 min of hand shaking in phosphate-buffered saline or deionized water, a 30-s settling time, one-rinse step and a 10 : 1 eluant volume to sand weight ratio. This result was consistent across the sand compositions tested in this study but could vary for other sand types.

SIGNIFICANCE AND IMPACT OF THE STUDY

Method standardization will improve the understanding of how sands affect surface water quality.

Systems biology of the neurospora biological clock

A major challenge of systems biology is explaining complex traits, such as the biological clock, in terms of the kinetics of macromolecules. The clock poses at least four challenges for systems biology: (i) identifying the genetic network to explain the clock mechanism quantitatively; (ii) specifying the clock's functional connection to a thousand or more genes and their products in the genome; (iii) explaining the clock's response to light and other environmental cues; and (iv) explaining how the clock's genetic network evolves. Here, the authors illustrate an approach to these problems by fitting an ensemble of genetic networks to microarray data derived from oligonucleotide arrays with approximately all 11 000 Neurospora crassa genes represented. A promising genetic network for the clock mechanism is identified.

Epimedium-derived phytoestrogen exert beneficial effect on preventing steroid-associated osteonecrosis in rabbits with inhibition of both thrombosis and lipid-deposition

OBJECTIVES

This study tested the effect of Epimedium-derived phytoestrogen (PE) on preventing steroid-associated osteonecrosis (ON) in rabbit model.

METHODS

Thirty 28-week-old male New-Zealand white rabbits were divided into control group (CON; n=14) and PE group (PE; n=16; 5 mg/kg body weight/day) after receiving an established inductive protocol for inducing steroid-associated ON. Before and after inductive protocol, Dynamic-MRI was employed on bilateral femora for local intra-osseous perfusion, blood samples were examined for coagulation, fibrinolysis and lipid-transportation, and marrow samples were quantified for adipogenesis-gene mRNA expression. Six weeks later, bilateral femora were dissected for Micro-CT-based micro-angiography, and then ON lesion, intravascular thrombosis and extravascular fat-cell-size were examined histopathologically.

RESULTS

The incidence of ON in the PE group (31%) was significantly lower than that in the CON group (93%). Compared to the CON group, local intra-osseous perfusion was maintained in the PE group. Blocked trunk vessels were seldom found in micro-angiography of the PE-treated rabbits. Thrombosis incidence and fat-cell-size were both significantly lower in the PE group than those in the CON group. During the early period after induction, indicator of coagulation, fibrinolysis, lipid-transportation and adipogenesis-gene expression were found with significantly changing pattern in the PE group compared to the CON group.

CONCLUSION

PE was able to exert beneficial effect on preventing steroid-associated ON in rabbits with inhibition of both thrombosis and lipid deposition.

Comprehensive Two-Dimensional Gas Chromatography for Fast Screening of Wash Oils

Fast screening of wash oils is demonstrated using comprehensive two-dimensional gas chromatography (GCxGC). Wash oils are used in ethylene production plants to minimize compressor fouling. The composition of a wash oil determines its effectiveness in solubilizing heavy hydrocarbons. In particular, the relative amount of 1- and 2-ring aromatics is important. The presence of oxygenates is undesirable because of adverse effects to the process. It is shown that GCxGC is well suited for this application. Species in wash oils are separated and grouped into three bands: a nonpolar aliphatics band, 1- and 2-ring aromatics band, and polyaromatics band. For a given polar secondary column, the spacing between bands in the second dimension can be adjusted in a broad range by selecting a primary column and an oven-temperature-programming rate. Integration of GCxGC peaks is evaluated using a standard GC integration program and a new GCxGC integration program. Consistent results are obtained using both programs for well-separated GCxGC peaks with relative differences for individual peak ranging from 0.04% to 1.6%. Peak responses are integrated by the GCxGC software, and the relative amounts of aromatics content and aliphatics content are estimated by peak response percent with relative standard deviations ranging from 0.15% to 2.8% (n = 3).

Cerebral vasomotor reactivity testing in head injury: the link between pressure and flow

BACKGROUND

It has been suggested that a moving correlation index between mean arterial blood pressure and intracranial pressure, called PRx, can be used to monitor and quantify cerebral vasomotor reactivity in patients with head injury.

OBJECTIVES

To validate this index and study its relation with cerebral blood flow velocity and cerebral autoregulation; and to identify variables associated with impairment or preservation of cerebral vasomotor reactivity.

METHODS

The PRx was validated in a prospective study of 40 head injured patients. A PRx value of less than 0.3 indicates intact cerebral vasomotor reactivity, and a value of more than 0.3, impaired reactivity. Arterial blood pressure, intracranial pressure, mean cerebral perfusion pressure, and cerebral blood flow velocity, measured bilaterally with transcranial Doppler ultrasound, were recorded. Dynamic cerebrovascular autoregulation was measured using a moving correlation coefficient between arterial blood pressure and cerebral blood flow velocity, the Mx, for each cerebral hemisphere. All variables were compared in patients with intact and impaired cerebral vasomotor reactivity.

RESULTS

No correlation between arterial blood pressure or cerebral perfusion pressure and cerebral blood flow velocity was seen in 19 patients with intact cerebral vasomotor reactivity. In contrast, the correlation between these variables was significant in 21 patients with impaired cerebral vasomotor reactivity, whose cerebral autoregulation was reduced. There was no correlation with intracranial pressure, arterial blood pressure, cerebral perfusion pressure, or interhemispheric cerebral autoregulation differences, but the values for these indices were largely within normal limits.

CONCLUSIONS

The PRx is valid for monitoring and quantifying cerebral vasomotor reactivity in patients with head injury. This intracranial pressure based index reflects changes in cerebral blood flow and cerebral autoregulatory capacity, suggesting a close link between blood flow and intracranial pressure in head injured patients. This explains why increases in arterial blood pressure and cerebral perfusion pressure may be useful for reducing intracranial pressure in selected head injured patients (those with intact cerebral vasomotor reactivity).

The Adolescent Food Habits Checklist: reliability and validity of a measure of healthy eating behaviour in adolescents

OBJECTIVE

Amid concerns about the quality of young people's diets, this paper describes the development of a measure of healthy eating behaviour for use with adolescents.

DESIGN

Items for the measure were selected from a larger pool on the basis of responses from a pilot study. The 23-item checklist was validated using measures of dietary fat and fibre intake, fruit and vegetable consumption, dietary restraint, nutrition knowledge and a measure of family income.

SETTING

Participants came from seven secondary schools in the north-west of England.

SUBJECTS

A total of 1822 adolescents aged between 13 and 16 y took part in the study, representing 84% of those invited to participate.

RESULTS

Correlations between measures indicate a good level of convergent validity, and the checklist is also shown to have high internal and test-retest reliability.

CONCLUSIONS

The focus on choices available to adolescents means that the checklist will provide a useful addition to food frequency-type approaches to the measurement of adolescent eating behaviour.

SPONSORSHIP

This research was funded by the Medical Research Council and the Economic and Social Research Council's Health Variations Programme.

Clinical significance of P-glycoprotein immunohistochemistry and doxorubicin binding assay in patients with osteosarcoma

In 45 osteosarcoma patients, mean age 18 (4-61) years and followed for 14 (5-48) months, we studied the sensitivity to doxorubicin as well as P-glycoprotein expression, and compared these with the extent of tumour necrosis following chemotherapy. Doxorubicin assay was positive in 37 patients in whom necrosis induced by chemotherapy was good in 20 and poor in 17. Metastases developed in nine patients. In eight patients in whom doxorubicin assay indicated tumour resistance, chemonecrosis was poor and all developed pulmonary metastases. P-glycoprotein was studied in pre-treatment biopsies and post-treatment resection specimens. Its expression was positive in 16 patients in whom the necrosis induced by chemotherapy was good in four and poor in 12. In 29 patients with negative P-glycoprotein expression, necrosis was good in 16 and poor in 13. The doxorubicin sensitivity had a high correlation with chemonecrosis (P=0.006) and the incidence of metastases (P<0.001). However, P-glycoprotein expression at the time of diagnosis did not correlate statistically with chemonecrosis (P=0.066). Doxorubicin sensitivity prior to treatment is a better determinant of the response to chemotherapy and clinical outcome than is the P-glycoprotein expression.

Laboratory enhanced surveillance for meningococcal disease in Victoria

OBJECTIVE

To describe the epidemiological and microbiological characteristics and notification patterns of invasive meningococcal disease (IMD) in Victoria between 1990 and 1999.

METHODS

Cases of IMD occurring between 1990 and 1995 identified in any of three databases were combined, matching where possible. Statistical modelling provided estimates of cases missing from all datasets. Notification sources for 1999 and 2000 cases were identified. Cases identified from notification and laboratory results provided the data to describe IMD epidemiology between 1990 and 1999.

RESULTS

Between 1990 and 1995, 479 cases of IMD were identified. Three individual datasets each identified between 62 and 82% of cases and 47% of cases were identified in all three datasets. Statistical modelling estimated that between 37 and 83 additional cases were not identified by any dataset. Serogroup B and C strains caused 63 and 33% of culture-positive cases, respectively, with a substantial rise in serogroup C cases in 1999. Epidemiological characteristics remained relatively constant between 1990 and 1998, but an increase in patient age was seen in cases with serogroup C disease in 1999. In addition to three clonal strains seen elsewhere, an additional strain was identified that was unique to Victoria. Since January 1999, only 72% of notifications have come from treating doctors.

CONCLUSIONS

Meningococcal disease is of increasing public health significance in Victoria. Laboratory enhanced notification has improved case identification and detailed microbiological information has improved our understanding of the changing epidemiology of this disease. Collaboration with laboratories and other agencies, active investigation of putative cases and microbiological monitoring are important elements in supporting public health decisions about the control of IMD.

Reorganization of multivesicular bodies regulates MHC class II antigen presentation by dendritic cells

Immature dendritic cells (DCs) sample their environment for antigens and after stimulation present peptide associated with major histocompatibility complex class II (MHC II) to naive T cells. We have studied the intracellular trafficking of MHC II in cultured DCs. In immature cells, the majority of MHC II was stored intracellularly at the internal vesicles of multivesicular bodies (MVBs). In contrast, DM, an accessory molecule required for peptide loading, was located predominantly at the limiting membrane of MVBs. After stimulation, the internal vesicles carrying MHC II were transferred to the limiting membrane of the MVB, bringing MHC II and DM to the same membrane domain. Concomitantly, the MVBs transformed into long tubular organelles that extended into the periphery of the cells. Vesicles that were formed at the tips of these tubules nonselectively incorporated MHC II and DM and presumably mediated transport to the plasma membrane. We propose that in maturing DCs, the reorganization of MVBs is fundamental for the timing of MHC II antigen loading and transport to the plasma membrane.

S-adenosylmethionine decarboxylase overexpression reduces invasiveness and tumorigenicity in nude mice of MCF-7 breast cancer cells

To elucidate the role of S-adenosylmethionine decarboxylase (SAMDC) in breast cancer biology, we have generated SAMDC overexpressing MCF-7 breast cancer cells. SAMDC overexpression did not alter in a major way growth properties of MCF-7 cells in soft agar, either under basal conditions or in response to estrogen and antiestrogen administration. SAMDC-MCF-7 cells, on the other hand, exhibited a markedly reduced invasive ability in matrigel (p=0.013). Furthermore, they were less tumorigenic in nude mice. The odds for control clones to form tumors were 3.13 (C.1.1.2-8.2, p=0.0184) higher than those for SAMDC clones. The odds ratio were identical in the absence and in the presence of estradiol. In addition, the growth rate of established tumors was slower for SAMDC than for control clones. Overall, our results are consistent with the notion that these phenotypic changes induced by SAMDC overexpression are primarily mediated by suppression of cellular putrescine (and, possibly, spermidine) levels.

Surveillance of antibiotic resistance in invasive isolates of Neisseria meningitidis in Australia 1994-1999

A total of 1434 strains of Neisseria meningitidis isolated from cases of invasive meningococcal disease (IMD) in Australia between 1994 and 1999 were examined by standard methods for susceptibility to antibiotics used for treatment and prophylaxis. The proportion of isolates fully susceptible to penicillin decreased from 45% in 1994 to 26% in 1999 (P<0.001). All the other isolates were less sensitive to penicillin except for two meningococci with a penicillin MIC of 1 mg/l. The geometric mean penicillin MIC increased from 0.045 to 0.065 mg/l from 1994 to 1999. There was no significant difference in the geometric mean penicillin MICs of serogroup B and serogroup C meningococci. Penicillin susceptibility was significantly associated with a poorer outcome. Isolates from survivors of IMD had a higher geometric mean penicillin MIC (0.06 mg/l) than those from fatal cases (0.048 mg/l) (P< 0.001). This suggests that factors other than the decrease in susceptibility to penicillin observed were more relevant to outcome in IMD. All isolates were fully susceptible to ceftriaxone. Rifampicin resistance was infrequent (eight isolates in 6 years) and sporadic. A single isolate had decreased quinolone susceptibility. Despite the significant shift in susceptibility to penicillin recorded, this group of antibiotics remains a suitable treatment for IMD in Australia.

An outbreak of serogroup C meningococcal disease associated with a secondary school

An outbreak of 3 cases of invasive meningococcal disease occurred in a secondary school on 2 campuses in Victoria. Despite having only one isolate (a C.2a:nst strain), meningococcal DNA was identified by polymerase chain reaction (PCR) in early culture-negative blood specimens of the other 2 cases. Both were subsequently shown by PCR to be capsule serogroup C by PCR. An committee was formed to manage the response to the outbreak. Chemoprophylaxis was offered to family and children who had been in close contact with the cases. As one strain had been confirmed as being of a vaccine-preventable group, vaccination was offered to the whole school community as well as the families of cases. The direct costs of the outbreak to public health, which would have been identical whatever the causative serogroup, was $8,178. Vaccine charges accounted for most of the additional $56,941 cost of vaccinating the target group of 1600 students, staff, and families. No further cases have been associated with this outbreak.

Prokaryote multidrug efflux proteins of the major facilitator superfamily: amplified expression, purification and characterisation

In bacterial genomes 3-12% of open reading frames are predicted to encode membrane transport proteins. These proteins can be vital for antibiotic efflux, protein/ toxin secretion, cell nutrition, environmental sensing, ATP synthesis, and other functions. Some, such as the multidrug efflux proteins, are potential targets for the development of new antibacterials and also for applications in biotechnology. In general membrane transport proteins are poorly understood, because of the technical difficulties involved in isolating sufficient protein for elucidation of their structure-activity relationships. We describe a general strategy for the amplified expression, purification and characterisation of prokaryotic multidrug efflux proteins of the 'Major facilitator superfamily' of transport proteins, using the Bacillus subtilis multidrug resistance protein, 'Bmr', as example.

Socioeconomic status and weight control practices in British adults

STUDY OBJECTIVE

Attitudes and practices concerning weight control in British adults were examined to test the hypothesis that variation in concern about weight and deliberate weight control might partly explain the socioeconomic status (SES) gradient in obesity. Higher SES groups were hypothesised to show more weight concern and higher levels of dieting.

SETTING

Data were collected as part of the monthly Omnibus Survey of the Office of National Statistics in March 1999.

PARTICIPANTS

A stratified, probability sample of 2690 households was selected by random sampling of addresses in Britain. One randomly selected person in each household was interviewed at their home.

MAIN RESULTS

As predicted, higher SES men and women had higher levels of perceived overweight, monitored their weight more closely, and were more likely to be trying to lose weight. Higher SES groups also reported more restrictive dietary practices and more vigorous physical activity.

CONCLUSIONS

The results are consistent with the idea that part of the protection against weight gain in higher SES groups could be a higher frequency of weight monitoring, a lower threshold for defining themselves as overweight, and a greater likelihood of deliberate efforts at weight control.

The Neurospora crassa genome: cosmid libraries sorted by chromosome

A Neurospora crassa cosmid library of 12,000 clones (at least nine genome equivalents) has been created using an improved cosmid vector pLorist6Xh, which contains a bacteriophage lambda origin of replication for low-copy-number replication in bacteria and the hygromycin phosphotransferase marker for direct selection in fungi. The electrophoretic karyotype of the seven chromosomes comprising the 42.9-Mb N. crassa genome was resolved using two translocation strains. Using gel-purified chromosomal DNAs as probes against the new cosmid library and the commonly used medium-copy-number pMOcosX N. crassa cosmid library in two independent screenings, the cosmids were assigned to chromosomes. Assignments of cosmids to linkage groups on the basis of the genetic map vs. the electrophoretic karyotype are 93 +/- 3% concordant. The size of each chromosome-specific subcollection of cosmids was found to be linearly proportional to the size of the particular chromosome. Sequencing of an entire cosmid containing the qa gene cluster indicated a gene density of 1 gene per 4 kbp; by extrapolation, 11,000 genes would be expected to be present in the N. crassa genome. By hybridizing 79 nonoverlapping cosmids with an average insert size of 34 kbp against cDNA arrays, the density of previously characterized expressed sequence tags (ESTs) was found to be slightly <1 per cosmid (i.e., 1 per 40 kbp), and most cosmids, on average, contained an identified N. crassa gene sequence as a starting point for gene identification.

What is the impact of early rheumatoid arthritis on the individual?

Rheumatoid arthritis has a significant impact on patients' physical, emotional and social functioning that often occurs very early in the disease with the onset of symptoms. Patients therefore come to their consultation with the rheumatologist, having often experienced these symptoms over a period of some months, with specific expectations (for reassurance and diagnosis) and their own understanding and beliefs about the aetiology and prognosis of their symptoms. Information and advice given by rheumatologists will be rejected by patients if it cannot be accommodated within these lay beliefs. The diagnosis itself can cause a variety of reactions, including relief, disbelief, anger, fear and devastation. Following diagnosis, patients are faced with the problems of adapting to a new self-concept, managing their symptoms and trying to assimilate the large amount of information that they are given about their disease, its treatment, preferred health behaviours, prognosis and so on. There are a number of ways in which health professionals can reduce this impact in early disease. Eliciting patients' lay beliefs about the cause of their symptoms will ensure that information given in the consultation is relevant to individual patients and is presented in a way that has meaning for them. Determining patients' expectations of the rheumatologist will ensure that patients' needs for information and reassurance are met and that unrealistic or inappropriate expectations can be discussed and re-negotiated. Understanding patients' attitudes towards treatment interventions will inform shared clinical decision-making and promote adherence. Obtaining this information in the context of a time-limited consultation can be assisted by the use of validated clinical tools, presented as self-completed questionnaires. Further research is needed to determine the content, frequency, timing and methodology of educational interventions in early rheumatoid arthritis and to improve the understanding of the complex interaction between lay beliefs and disease outcome.

Monostotic fibrous dysplasia of the spine: report of a case involving the lumbar transverse process and review of the literature

Monostotic fibrous dysplasia of the spine is rare. We report its clinical, radiologic and histologic features affecting a 47-year-old housewife. She presented with low-back pain of 1-year's duration, and radiographs showed a diffuse expansile lesion in the left transverse process of the fourth lumbar vertebra. The lesion was excised and histologically confirmed to be fibrous dysplasia. The patient remained well 8 years after operation. Including the present case, a total of 22 cases of monostotic fibrous dysplasia of the spine were found in the literature. Combining these reported cases, we found that the condition affects either sex with equal frequency and presents at any age, the mean being 32 years. There is no predilection for any part of the spinal column, though sacral or coccygeal involvement is distinctly rare. It most commonly involves the body and adjacent pedicle, although no part of the vertebra is spared. It is worth noting that a propensity for progressive enlargement, even to the extent of causing graft destruction, exists if the lesion is left untreated or incompletely treated. Complete removal of all involved bone, together with stabilization, should therefore be the treatment of choice for this condition.

Alendronate prevents bone loss in Chinese women with osteoporosis

The objectives of the Hong Kong study are to investigate the efficacy of 10 mg alendronate in preventing bone loss at the hip and spine in osteoporotic Chinese women. One hundred osteoporotic Chinese women, aged 60-79 years, were randomized to receive 10 mg of alendronate or placebo, with 500 mg elemental calcium. Bone mineral density (BMD) at the spine and hip were measured at baseline, 6 months, and 12 months. Seventy-eight subjects completed the study. The alendronate-treated group gained more bone at both the spine (p < 0.01) and femoral neck (p < 0.001), with a mean difference (+/-SE) of 2.4% (+/-0.86%) at the spine and 3.98% (+/-0.95%) at the femoral neck. Of the 100 patients, 6 subjects in the alendronate group and 5 subjects in the placebo group had mild gastrointestinal symptoms. We conclude that alendronate (10 mg) was effective in preventing bone loss in postmenopausal osteoporotic Chinese women.

Auditory P50 in schizophrenics on clozapine: improved gating parallels clinical improvement and changes in plasma 3-methoxy-4-hydroxyphenylglycol

Schizophrenic patients have decreased inhibition of the P50 auditory evoked potential response to the second of two paired click stimuli delivered 500 ms apart. This deficit in inhibitory gating does not change during treatment with typical neuroleptics. We recently reported that neuroleptic-resistant schizophrenics had enhanced P50 gating after 1 month of clozapine treatment, if they responded with decreased clinical symptoms. This study reports the outcome of more prolonged treatment. Ten treatment-refractory schizophrenic patients were studied at baseline, after 1 month on clozapine, and again after 15 +/- 6.1 (SD) months of clozapine treatment. Eight subjects reached a clinically stable improved state, at which time they had significantly improved P50 auditory gating. One patient had a return of impaired gating after stopping clozapine, as did another during a clinical relapse. Decreasing plasma 3-methoxy-4-hydroxyphenylglycol levels with clozapine treatment were correlated with improved P50 gating and improved Brief Bsychiatric Rating Scale-positive scores. This study provides further evidence that improved P50 gating in schizophrenic patients treated with clozapine coincides with clinical improvement and that this improvement can be sustained for at least 1 year.

Intentional weight control and food choice habits in a national representative sample of adults in the UK

OBJECTIVE

To establish the association between intentional weight control and specific eating behaviours.

DESIGN

An interview-based survey of a representative sample of the UK population including questions about demographic characteristics, weight and height, intentional weight control and eating behaviours. Associations among the eating behaviours, and between weight control and eating behaviours, were examined.

SUBJECTS

1894 men and women completed the interview (70% response rate).

RESULTS

Approximately equal proportions of the sample were 'not bothered about weight' (30%), 'watching their weight' (36%), or 'trying to lose weight' (28%). More men were 'not bothered' and more women were 'trying to lose'. People who were trying to lose or were watching their weight were more likely to report restricting fats, sugars, snacks, and the amount eaten at meals, than those who were not bothered, but there were no differences between weight watchers and weight losers. The overall level of restriction among weight losers was modest. There were no group differences in eating breakfast, fruits or vegetables, skipping meals or fasting.

CONCLUSIONS

Around two-thirds of the adult population of the UK appear to be concerned about weight control, and this is reflected in somewhat higher than average adherence to recommended restrictive dietary habits.

Carcinoembryonic antigens are targeted by diverse strains of typable and non-typable Haemophilus influenzae

Haemophilus influenzae (Hi), a commensal of the human respiratory mucosa, is an important cause of localized and systemic infections. We show that distinct strains belonging to typable (THi) and non-typable (NTHi) H. influenzae target human carcinoembryonic antigens (the membrane associated CEA family of cell adhesion molecules, are now termed CEACAMs). All strains of H. influenzae biogroup aegyptius (Hi-aeg) and more than 70% of THi and NTHi strains tested specifically recognize CEACAMI-Fc soluble constructs. Furthermore, transfection of Chinese hamster ovary cells with human CEACAM1 cDNA alone was sufficient for promoting Hi interactions with the transfected cells. The majority of the Hi-aeg strains tested interacted with soluble constructs containing only the N-terminal domain. In contrast, several THi and NTHi strains reacted with soluble constructs only when additional extracellular A and B domains of the receptor were present. The use of monoclonal antibodies confirmed that THi and NTHi strains also interact primarily at the N-domain. We used site-directed mutants of CEACAM1 that contained substitutions at surface exposed amino acids and a molecular model of the N-domain to identify the residues involved in interactions with Hi ligands. The studies show that a common region exposed at the CFG face of the molecule is targeted by diverse Hi strains. However, mutation at distinct sites within this area affected the interactions of distinct strains signifying the potential for tissue tropism via this receptor. Analyses of the molecular basis of interaction with human cell lines and purified CEA show that Hi strains, especially those belonging to Hi-aeg, interact with multiple CEACAMs. Because Neisseria meningitidis (Nm) strains are also known to bind at the CFG face of the receptor, we used Nm and Hi strains in co-infection experiments and demonstrate competition between these mucosal pathogens in colonization of target cells via CEACAMs.

Varicella zoster virus infections following allogeneic bone marrow transplantation: frequency, risk factors, and clinical outcome

Reactivation of varicella zoster virus (VZV) is a common event in patients undergoing allogeneic bone marrow transplantation (BMT) and may lead to life-threatening complications. We retrospectively analyzed the incidence, clinical outcome, and risk factors for VZV infections occurring within the first 5 years of transplantation in 100 consecutive adults undergoing allogeneic BMT between 1992 and 1997. Forty-one patients (41%) developed VZV reactivation a median of 227 days (range 45-346 days) post-transplantation. Twelve percent of VZV reactivation occurred in the first 100 days and 88% within the first 24 months. Among those who survived for 2 or more years after transplantation (n = 47), 59% developed VZV infection. Forty percent of patients with VZV reactivation required admission with a mean hospital stay of 7.2 days. Two patients developed encephalitis, and 1 died despite antiviral therapy. The most frequent complications were post-herpetic neuralgia and peripheral neuropathy (68%). Thoracic dermatomal zoster represented 41% of the infections; disseminated cutaneous involvement was observed in 17% of patients. No clinical or epidemiologic risk factors were associated with recurrence. Administration of ganciclovir for prevention of cytomegalovirus infection delayed the onset of VZV infection beyond 4 months (P = .06). In a further subset analysis, patients with a limited chronic graft-versus-host disease (GVHD) had a lower estimated incidence of VZV reactivation compared with those with extensive chronic GVHD (P = .11). We conclude that complications from reactivation of VZV infection are common and associated with considerable morbidity and mortality in patients undergoing allogeneic BMT.

Job strain and anger expression predict early morning elevations in salivary cortisol

OBJECTIVE

The objectives of this study were to test the hypothesis that high job demands and low job control (job strain) are associated with elevated free cortisol levels early in the working day and with reduced variability across the day and to evaluate the contribution of anger expression to this pattern.

METHODS

One hundred five school teachers (41 men and 64 women) classified 12 months earlier as high (N = 48) or low (N = 57) in job strain according to the demand/control model sampled saliva at 2-hour intervals from 8:00 to 8:30 hours to 22:00 to 22:30 hours on a working day. Anger expression was assessed with the Speilberger State-Trait Anger Expression Inventory, and negative affect was also measured.

RESULTS

Free cortisol was significantly elevated at 8:00 to 8:30 hours in the high job strain group but not at later times of the day or evening. After adjustment for age and negative affect, cortisol was an average of 21.7% higher early in the working day in the high job strain group. This effect was significantly greater in high job strain teachers, who also reported high anger-out. The cortisol decline from morning to evening was greater in the high than low job strain individuals. Independently of job strain, women had a higher cortisol concentration at 8:00 to 8:30 hours than men, whereas cortisol concentration was greater in men than women in the middle of the working day between 12:00 and 16:30 hours.

CONCLUSIONS

Job strain is associated with elevated free cortisol concentrations early in the working day but not with reduced cortisol variability. The interaction with outward anger expression suggests that individual characteristics modulate the impact of chronic work stress on the hypothalamic-pituitary-adrenocortical system.

Vertebral deformity in chinese men: prevalence, risk factors, bone mineral density, and body composition measurements

The prevalence and risk factors for vertebral deformity were studied in 396 community-dwelling Chinese men aged 70-79 years. Anterior to posterior (H(a)/H(p)), middle to posterior (H(m)/H(p)) and posterior to posterior (H(p)/H(p - 1) or H(p)/H(p + 1)) ratios from T5 to L5 were derived from lateral spine X-ray films, using standardized digitization methods. Using values of 3 standard deviations (SD) or more below the mean and 4 SD or more below the mean as the cutoff, 16% and 7% of these men, respectively, were deemed to have one or more deformed vertebra. Heavy cigarette smoking, heavy alcohol consumption, and working as a heavy manual worker were risk factors for vertebral deformity. Men with severe vertebral deformity (VHR < mean - 4 SD below mean) had much lower body weight, fat mass, and bone mineral density (BMD) than controls. The odds ratios for severe vertebral deformity was 9.9 (95% CI 2.1-45.7) in the lowest quartile of femoral neck BMD.

An investigation of coping strategies associated with job stress in teachers

BACKGROUND

School teaching is regarded as a stressful occupation, but the perception of the job as stressful may be influenced by coping responses and social support.

AIMS

To assess the associations between teacher stress, psychological coping responses and social support, taking into account the plaintive set engendered by negative affectivity.

METHOD

Questionnaire survey of 780 primary and secondary school teachers (53.5% response rate).

RESULTS

In stepwise multiple regression, social support at work and the coping responses behavioural disengagement and suppression of competing activities predicted job stress independently of age, gender, class size, occupational grade and negative affectivity. High job stress was associated with low social support at work and greater use of coping by disengagement and suppression of competing activities.

CONCLUSIONS

It is suggested that behavioural disengagement and suppression of competing activities are maladaptive responses in a teaching environment and may actually contribute to job stress. Coping and social support not only moderate the impact of stressors on well-being but influence the appraisal of environmental demands as stressful.

Association between outcome and telomere DNA content in prostate cancer

PURPOSE

To perform an initial retrospective investigation of the relationship between outcome in patients with organ confined prostate adenocarcinoma and the tumor cells' content of telomere DNA.

MATERIALS AND METHODS

The case-controlled study group was composed of eighteen men diagnosed with prostatic adenocarcinoma prior to 1993. The group was selected so that approximately one half died within ten years of diagnosis and one half survived ten years or longer. Archival, paraffin-embedded tumor tissue was recovered for each patient. DNA was extracted from newly cut sections, fixed to nylon membranes and hybridized with P32-labeled centromere- and telomere-specific probes. Telomere DNA contents were quantitated from the hybridized radioactivities. The relationships between telomere DNA content and survival, and telomere DNA content and disease recurrence in men receiving prostatectomies were determined.

RESULTS

Death and disease recurrence were associated with reduced telomere DNA content (p <0.0001, p <0.0001, respectively).

CONCLUSIONS

Telomere DNA content may differentiate high-risk patients with metastatic prostate cancer from men with indolent disease who can be spared the unnecessary side effects and expense of treatment by management with "watchful waiting."

Clinical utility of blood cultures drawn from indwelling central venous catheters in hospitalized patients with cancer

BACKGROUND

Because of concern about low specificity, the American College of Physicians guidelines and expert opinion discourage the use of a central venous catheter when obtaining blood for culture for bacteremia or fungemia. However, data on the reliability of cultures done with blood obtained from a central venous catheter are conflicting.

OBJECTIVE

To determine the sensitivity, specificity, and positive and negative predictive values of cultures done with blood obtained through a central venous catheter compared with peripheral venipuncture.

DESIGN

Retrospective cohort study of hospitalized patients with cancer in whom samples for paired cultures were drawn through a central venous catheter and peripheral venipuncture.

SETTING

Tertiary care, university-affiliated medical center.

PATIENTS

185 patients hospitalized on a hematology-oncology ward between August 1994 and June 1996.

MEASUREMENTS

Blinded assessments of culture results done by infectious disease experts were used as the gold standard. Sensitivity, specificity, and positive and negative predictive values were compared for culture of blood from central catheters and culture of blood from peripheral venipuncture.

RESULTS

Of 551 paired cultures, 469 (85%) were catheter-negative/venipuncture-negative, 32 (6%) were catheter-positive/venipuncture-positive, 17 (3%) were catheter-negative/venipuncture-positive, and 33 (6%) were catheter-positive/venipuncture-negative pairs. For the 82 paired cultures with at least one positive result, blinded determination of true bacteremia or fungemia was made by two infectious disease specialists. For catheter draw compared with peripheral venipuncture, sensitivity was 89% (95% CI, 79% to 98%) and 78% (CI, 65% to 90%) (difference, 11 percentage points [CI, -6 to 28 percentage points]), specificity was 95% (CI, 93% to 97%) and 97% (CI, 96% to 99%) (difference, -2 percentage points [CI, -5 to 0.2 percentage points]), positive predictive value was 63% (CI, 50% to 75%) and 73% (CI, 60% to 86%) (difference, -10 percentage points [CI, -26 to 5 percentage points]), and negative predictive value was 99% [CI, 97% to 100%]) and 98% (CI, 96% to 100%) (difference, 1 percentage point [CI, -0.5 to 3 percentage points]).

CONCLUSIONS

In hospitalized hematology-oncology patients, culture of blood drawn through either the central catheter or peripheral vein shows excellent negative predictive value. Culture of blood drawn through an indwelling central venous catheter has low positive predictive value, apparently less than from a peripheral venipuncture. Therefore, a positive result from a catheter needs clinical interpretation and may require confirmation. However, the use of a catheter to obtain blood for culture may be an acceptable method for ruling out bloodstream infections.

The influence of abdominal obesity and chronic work stress on ambulatory blood pressure in men and women

OBJECTIVE

To assess the influence of abdominal obesity and work stress (operationalised as low control over work) on ambulatory blood pressure on a working day and evening.

PARTICIPANTS AND METHODS

156 school teachers (58 men and 98 women) carried out ambulatory blood pressure and heart rate monitoring on a work day and evening. Cardiovascular activity was also measured under baseline conditions on another occasion, when body weight, height, waist and hip circumference were assessed. Perceived control over work was assessed by questionnaire, along with mental health, anger expression and social support. 126 participants repeated the protocol after 12 months. Waist/hip ratio was used as the index of abdominal obesity.

RESULTS

Baseline blood pressure was positively associated with waist/hip ratio in men, but ambulatory blood pressure and heart rate were not independently related to waist/hip ratio or job control. However, blood pressure and heart rate recorded during the working day and evening were elevated in men with high waist/hip ratio who experienced low job control, independently of age and body weight. Effects for diastolic blood pressure and heart rate were replicated after 12 months. Body mass index was not related to blood pressure or heart rate during the day or evening after adjustment for age and waist circumference. Low job control was associated with poor psychological well-being, negative mood and lack of social support.

CONCLUSIONS

The results are consistent with the hypothesis that abdominal obesity in men is characterised by a tendency towards heightened stress-induced physiological activation, but that this tendency will only be manifest in the presence of appropriate environmental challenges such as chronic work stress.

Ambulatory blood pressure monitoring is associated with reduced physical activity during everyday life

OBJECTIVE

The objective of this study was to assess the impact on noninvasive ambulatory blood pressure monitoring on physical activity measured objectively by use of triaxial accelerometers.

METHODS

Twenty-four working men and women performed ambulatory blood pressure plus activity monitoring for 1 working day and evening and activity monitoring alone for a separate day and evening. Blood pressure measures were taken at 20-minute intervals during the day and 30-minute intervals in the evening and were accompanied by diary assessments of mood, location, and posture. Comparisons were made of energy expenditure on the 2 days and of activity levels during the minutes surrounding each blood pressure reading and diary completion.

RESULTS

Energy expenditure assessed in terms of activity calories per hour was significantly lower during blood pressure plus activity monitoring compared with activity monitoring alone (mean 37.3, SD = 16.3 vs. mean = 43.0, SD = 18.7 kcal, respectively: p = .02). Energy expenditure was lower during the 4 minutes surrounding each blood pressure reading than in the intervals between blood pressure readings. However, energy expenditure was also lower in the intervals between blood pressure readings than during comparable times on the activity only monitoring day. Blood pressure, heart rate, and physical activity were moderately correlated within individuals.

CONCLUSIONS

Ambulatory blood pressure recording using automated sphygmomanometers is associated with reduced physical activity during the monitoring day. This is due partly to regular periods of immobility during cuff inflation and deflation and diary completion and partly to more general self-imposed restrictions on activity. This pattern has implications for the representativeness of ambulatory blood pressure monitoring, and the construction of ambulatory monitoring diaries.

Association between outcome and telomere DNA content in prostate cancer

PURPOSE

To perform an initial retrospective investigation of the relationship between outcome in patients with organ confined prostate adenocarcinoma and the tumor cells' content of telomere DNA.

MATERIALS AND METHODS

The case-controlled study group was composed of eighteen men diagnosed with prostatic adenocarcinoma prior to 1993. The group was selected so that approximately one half died within ten years of diagnosis and one half survived ten years or longer. Archival, paraffin-embedded tumor tissue was recovered for each patient. DNA was extracted from newly cut sections, fixed to nylon membranes and hybridized with P32-labeled centromere- and telomere-specific probes. Telomere DNA contents were quantitated from the hybridized radioactivities. The relationships between telomere DNA content and survival, and telomere DNA content and disease recurrence in men receiving prostatectomies were determined.

RESULTS

Death and disease recurrence were associated with reduced telomere DNA content (p <0.0001, p <0.0001, respectively).

CONCLUSIONS

Telomere DNA content may differentiate high-risk patients with metastatic prostate cancer from men with indolent disease who can be spared the unnecessary side effects and expense of treatment by management with "watchful waiting."

Substance abuse disorders in nurses

Substance abuse is a serious concern in the profession of nursing. The American Nurses Association (1997) estimates that 10% to 20% of nurses have substance abuse problems, and that 6% to 8% of registered nurses are impaired due to their abuse of alcohol and other drugs. Chemical dependency is considered a disease that requires treatment. Early identification and treatment of the chemically dependent nurse is important for the safety of the public and for the well-being of the nurse and her profession. This article addresses substance abuse from a biopsychosocial perspective, and includes a description of an approach to treatment and suggestions for the role of nursing administration.

Visualization of double-stranded RNAs from the myotonic dystrophy protein kinase gene and interactions with CUG-binding protein

Myotonic dystrophy (DM) is associated with a (CTG) (n) triplet repeat expansion in the 3'-untranslated region of the myotonic dystrophy protein kinase (DMPK) gene. Using electron microscopy, we visualized large RNAs containing up to 130 CUG repeats and studied the binding of purified CUG-binding protein (CUG-BP) to these RNAs. Electron microscopic examination revealed perfect double-stranded (ds)RNA segments whose lengths were that expected for duplex RNA. The RNA dominant mutation model for DM pathogenesis predicts that the expansion mutation acts at the RNA level by forming long dsRNAs that sequester certain RNA-binding proteins. To test this model, we examined the subcellular distribution and RNA-binding properties of CUG-BP. While previous studies have demonstrated that mutant DMPK transcripts accumu-late in nuclear foci, the localization pattern of CUG-BP in both normal and DM cells was similar. Although CUG-BP in nuclear extracts preferentially photocrosslinked to DMPK transcripts, this binding was not proportional to (CUG) (n) repeat size. Moreover, CUG-BP localized to the base of the RNA hairpin and not along the stem, as visualized by electron micro-scopy. These results provide the first visual evidence that the DM expansion forms an RNA hairpin structure and suggest that CUG-BP is unlikely to be a sequestered factor.

Classifying the location of osteosarcoma with reference to the epiphyseal plate helps determine the optimal skeletal resection in limb salvage procedures

Between 1989 and 1996, 21 skeletally immature patients were treated for osteosarcoma of the extremity. Their average age was 12.6 years (range 9-16 years). We classified the location and extent of the lesion in bone on magnetic resonance imaging (MRI) with reference to the growth plate and joint margin into five subtypes. This classification served as a guide for the level of resection and the type of reconstruction required for a limb salvage procedure. All patients received neoadjuvant chemotherapy using a modified T10 protocol before the definitive operation. These patients were followed up for periods ranging from 11-86 months, with a mean of 35. 5 months. Patients were assessed for (1) local tumour recurrence, (2) metastatic disease, (3) allograft complications and (4) extremity function and joint stability. Excellent function was retained in 2, good in 13 and fair function in 6 patients. The MRI classification proved useful for the resection and provides an insight into the possible functional outcomes.

A nursing home outbreak of Clostridium perfringens associated with pureed food

OBJECTIVE

To investigate and ascertain the source of a nursing home outbreak of gastroenteritis in Melbourne in 1997.

METHOD

A retrospective cohort study. We obtained fecal and food samples and environmental swabs, and reviewed food handling.

RESULTS

There were 25 cases, and 21 of these had their meals pureed (liquidised). The relative risk for eating pureed food and becoming ill was 5.8 (95% CI 2.2-15.4). Clostridium perfringens and its enterotoxin was detected in nine fecal samples. Samples of pureed food tested positive for coliforms.

CONCLUSIONS

This outbreak was caused by C. perfringens contaminating pureed food. Food liquidising provides opportunities for re-contamination of cooked food through the use of contaminated equipment and deficiencies in food handling practices. Pureed foods should be reheated to 70 degrees C after liquidising to inactivate pathogens.

IMPLICATIONS

Health care facilities need to take specific precautions to manage the special hazards involved in preparing pureed food.

Electron microscopy of DNA-protein complexes and chromatin

This article focused on a number of aspects of the preparation of chromatin and other DNA-protein complexes for conventional transmission EM that are critical for success but may not have been addressed in a single chapter before. These include the importance of optimizing fixation, the generation of active supporting supports, and the use of negative staining as a means of obtaining higher resolution detail than can be garnered from shadow casting methods.

Ten years after: examination of adolescent screening questions that predict future violence-related injury

PURPOSE

To determine which screening questions used in routine adolescent health care maintenance visits correlate with subsequent violence-related injury.

METHODS

A prospective cohort study was undertaken of adolescents initially seen at the East Boston Neighborhood Health Center (EBNHC) in 1986. Risk factor data were collected based on the adolescent health intake form in the medical records. The primary outcome measure, time until first violence-related injury was determined through identification on chart review of the treatment of any such injuries at the urgent care center at EBNHC in the subsequent 10 years. Kaplan-Meier survival statistics and Cox proportional hazards models were used to account for loss of patients to follow-up.

RESULTS

Median follow-up for this sample was >5 five years. Male gender, cigarette smoking, alcohol use, other drug use, poor relationships with parents, not being in school or failing school, and history of fighting in the past year, predicted violence-related injury within the follow-up period. The number of fights in the past year appeared to have a dose-response effect on risk of subsequent violence-related injury. A simple screening instrument consisting of items concerning school status, drug use, and fighting history was used to stratify youth into low, moderate, and high risk of violence-related injury during the follow-up period.

CONCLUSIONS

These results suggest that a simple three-item screening instrument may be used to stratify the risk of future injury at the time of adolescent health maintenance visits. Further research is indicated to validate this finding in other populations. Interventions designed to assist adolescents who are not in school or who have drug use problems should also incorporate violence prevention strategies.

Activity of recombinant HIV-1 integrase on mini-HIV DNA

Integration of the human immunodeficiency virus type 1 (HIV-1) cDNA into the genome of a human cell is an essential step in the viral replication cycle. Understanding of the integration process has been facilitated by the development of in vitro assays using specific oligonucleotides and recombinant integrase. However, understanding of the biology of retroviral integration will require in vitro and in vivo model systems using long DNA substrates that mimic the HIV cDNA. We have now studied the activity of recombinant HIV-1 integrase on a linear 4.7 kb double-stranded DNA, containing flanking regions of approximately 200 bp that represent the intact ends of the HIV-1 long terminal repeat (LTR) sequences (mini-HIV). The strand transfer products of the integration reaction can be directly visualized after separation in agarose gels by ethidium bromide staining. The most prominent reaction product resulted from integration of one LTR end into another LTR end (U5 into U5 and U5 into U3). Sequence analysis of the reaction products showed them to be products of legitimate integration preceded by correct processing of the viral LTR ends. Hotspots for integration were detected. Electron microscopy revealed the presence of a range of reaction products resulting from single or multiple integration events. The binding of HIV-1 integrase to mini-HIV DNA was visualized. Oligomers of integrase seem to induce DNA looping whereby the enzyme often appears to be bound to the DNA substrate that adopts the structure of a three-site synapsis that is reminiscent of the Mu phage transposase complex.

The dependence for leukocyte function-associated antigen-1/ICAM-1 interactions in T cell activation cannot be overcome by expression of high density TCR ligand

The leukocyte-specific integrin, LFA-1, can enhance T cell activation. However, it is unclear whether the binding of LFA-1 to its ligand, ICAM-1, functions through intercellular adhesion alone, resulting in an augmentation of the TCR signal, or involves an additional LFA-1-mediated cellular signal transduction pathway. We have previously shown that naive CD4+ lymph node T cells, isolated from DO11.10 TCR transgenic mice, are activated by increasing doses of exogenous OVA peptide presented by transfectants expressing both class II and ICAM-1, but not by cells expressing class II alone. To determine whether LFA-1/ICAM-1 interactions were simply enhancing the presentation of low concentrations of specific MHC/peptide complexes generated from exogenously added peptide, we transfected cells with class II that is covalently coupled to peptide, alone or in combination with ICAM-1. These cells express 100-fold more specific class II/peptide complexes than can be loaded onto class II-positive cells at maximum concentrations of exogenous peptide. Despite this high density of TCR ligand, activation of naive CD4+ T cells still requires the coexpression of ICAM-1. LFA-1/ICAM-1 interactions are not required for effective conjugate formation and TCR engagement because presentation of class II/peptide complexes in the absence of ICAM-1 does induce up-regulation of CD25 and CD69. Thus, high numbers of engaged TCR cannot compensate for the lack of LFA-1/ICAM-1 interactions in the activation of naive CD4+ T cells.

'Saccharomyces cerevisiae MSH2/6 complex interacts with Holliday junctions and facilitates their cleavage by phage resolution enzymes

Genetic and biochemical studies have indicated that mismatch repair proteins can interact with recombination intermediates. In this study, gel shift assays and electron microscopic analysis were used to show that the Saccharomyces cerevisiae MSH2/6 complex binds to Holliday junctions and has an affinity and specificity for them that is at least as high as it has as for mispaired bases. Under equilibrium binding conditions, the MSH2/6 complex had a Kd of binding to Holliday junctions of 0.5 nM. The MSH2/6 complex enhanced the cleavage of Holliday junctions by T4 endonuclease VII and T7 endonuclease I. This is consistent with the view that the MSH2/6 complex can function in both mismatch repair and the resolution of recombination intermediates as predicted by genetic studies.

Efficacy of a surfactant, allantoin, and benzalkonium chloride solution for onychomycosis. Preliminary results of treatment with periodic debridement

A 10-month, hospital-based, open-label clinical study was undertaken of a unique antimicrobial nail solution containing surfactant, allantoin, and benzaikonium chloride to determine its effectiveness, in conjunction with periodic debridement, against pedal onychomycosis. Forty patients with microbial infection of the nails were enrolled in this study, in which a new, objective nail-scoring system was used. At the start of the study, the mean nail score was 8.3, and 79.8% of the nails scored had severe disease (on a scale of 0 to 10, with 10 defined as total nail involvement, accompanied by pain and thickening). By the conclusion of the study, the mean score had decreased to 2.5, 32.6% of the patients' nails were scored 0 or 1, and 90% of the patients subjectively judged their improvement as excellent or good.

Clinical presentation, radiographic findings, and diagnostic methods of pulmonary blastomycosis: a review of 100 consecutive cases

BACKGROUND

We sought to determine the relationship among radiographic findings, clinical presentation, and diagnostic testing of pulmonary blastomycosis.

METHODS

We reviewed the medical records of 100 consecutive patients with pulmonary blastomycosis.

RESULTS

Air-space infiltrates were the usual radiographic finding of pulmonary blastomycosis. Mass-like infiltrates were associated more with chronic than acute presentations. Air-space and mass-like infiltrate were predominately involved in the upper lobes. Sputum analysis made the initial diagnosis of blastomycosis most often. Acute and chronic presentations were not different between immunosuppressed patients and the remainder of the patients. In addition, infiltrates on chest radiographs in immunosuppressed patients were similar to the other patients.

CONCLUSIONS

In an endemic area, pulmonary blastomycosis should be considered for any pulmonary infiltrate, especially in the upper lobes. Sputum analysis in most cases aids in the diagnosis, but bronchoscopy and/or tissue biopsy should be considered if the suspicion of blastomycosis is high and sputum analysis is inconclusive, negative, or not possible. Follow-up with chest radiographs after antifungal therapy is reasonable until complete resolution or fibrotic changes in patients with pulmonary blastomycosis.