The Chinese hamster FANCG/XRCC9 mutant NM3 fails to express the monoubiquitinated form of the FANCD2 protein, is hypersensitive to a range of DNA damaging agents and exhibits a normal level of spontaneous sister chromatid exchange

Fanconi anemia (FA) is a human autosomal disorder characterized by cancer susceptibility and cellular sensitivity to DNA crosslinking agents such as mitomycin C and diepoxybutane. Six FA genes have been cloned including a gene designated XRCC9 (for X-ray Repair Cross Complementing), isolated using a mitomycin C-hypersensitive Chinese hamster cell mutant termed UV40, and subsequently found to be identical to FANCG. A nuclear complex containing the FANCA, FANCC, FANCE, FANCF and FANCG proteins is needed for the activation of a sixth FA protein FANCD2. When monoubiquitinated, the FANCD2 protein co-localizes with the breast cancer susceptibility protein BRCA1 in DNA damage induced foci. In this study, we have assigned NM3, a nitrogen mustard-hypersensitive Chinese hamster mutant to the same genetic complementation group as UV40. NM3, like human FA cell lines (but unlike UV40) exhibits a normal spontaneous level of sister chromatid exchange. We show that both NM3 and UV40 are also hypersensitive to other DNA crosslinking agents (including diepoxybutane and chlorambucil) and to non-crosslinking DNA damaging agents (including bleomycin, streptonigrin and EMS), and that all these sensitivities are all corrected upon transfection of the human FANCG/XRCC9 cDNA. Using immunoblotting, NM3 and UV40 were found not to express the active monoubiquitinated isoform of the FANCD2 protein, although expression of the FANCD-L isoform was restored in the FANCG cDNA transformants, correlating with the correction of mutagen-sensitivity. These data indicate that cellular resistance to these DNA damaging agents requires FANCG and that the FA gene pathway, via its activation of FANCD2 and that protein's subsequent interaction with BRCA1, is involved in maintaining genomic stability in response not only to DNA interstrand crosslinks but also a range of other DNA damages including DNA strand breaks. NM3 and other "FA-like" Chinese hamster mutants should provide an important resource for the study of these processes in mammalian cells.

Epstein-Barr virus encoded latent membrane protein-1 induces epithelial cell proliferation and sensitizes transgenic mice to chemical carcinogenesis

EBV is found to be associated with 100% of poorly or undifferentiated nasopharyngeal carcinomas, a tumor of epithelial origin. The latent membrane protein-1 (LMP1) of EBV, may play a causal role in the development of this disease. The experiments initiated here were designed to examine the activity of LMP1 in vivo in the epidermis of PyLMP1 transgenic mice in relation to its putative role in carcinogenesis. Transgenic positive epidermis showed a 2-3-fold increase in the mitotic index, coupled with an increased level of expression of proliferative cytokeratin markers (K6 and K14) over controls. These results provide direct evidence that LMP1 induces proliferation in otherwise normal epithelial cells in vivo. To assess the role of LMP1 in tumorigenic progression, transgenic mice were treated topically with chemical carcinogens. PyLMP1 mice were highly sensitive to chemical carcinogens, developing significantly more small papillomas at a faster rate than controls. Furthermore, LMP1 could substitute for 12-O-tetradecanoylphorbol-13-acetate treatment in tumor promotion. However, LMP1 inhibited expansion of the benign lesions and did not enhance progression of the lesions to carcinomas or the progression of these to the more malignant spindle cell carcinomas. These data demonstrate that, early in the carcinogenic process, LMP1 acts as a tumor promoter after chemical initiation; but, paradoxically, it may also introduce a hurdle against expansion or progression of a lesion.

Birthweight distribution at Korle-Bu Teaching Hospital, Ghana

OBJECTIVES

To determine the birthweight distribution of singleton births at the Korle-Bu Teaching Hospital and to determine if selected socio-demographic and reproductive characteristics that are known to be associated with birthweight would show the association in our setting.

DESIGN

A non-randomised cross-sectional survey of all deliveries within the study period.

SETTING

Korle-Bu Teaching Hospital, a tertiary institution, delivering about 11,000 women a year.

STUDY POPULATION

From 1st November to 12th December 1994, 866 singleton normally formed livebirths and fresh stillbirths were sequentially enrolled.

DATA SOURCES

Data sources were the antenatal and delivery records of the subjects and an interviewer-administered questionnaire.

RESULTS

The mean birthweight for the total sample was 3070 g +/- 616 g. One hundred and fifteen (13.3%) babies were low birthweight. The mean birthweight for those with reliable dates and born at term was 3262 g +/- 488.8 g. Multiple logistic regression analysis showed lack of antenatal malaria chemoprophylaxis and a history of previous low birthweight to be significantly associated with low birthweight.

CONCLUSION

Although the mean birthweight of Korle-Bu babies was lower than those of USA and UK babies, it was comparable with those from other developing countries. Antenatal malaria chemoprophylaxis is a practical intervention that can produce an increase in mean birthweight and reduce the risk of low birthweight in our population.

Descriptive analysis of endemic cryptosporidiosis cases reported in Ontario, 1996-1997

Endemic cryptosporidiosis in Ontario was studied using notifiable disease data from the Ontario Ministry of Health for the years 1996-1997 inclusive. For this study period, 451 endemic cases were identified, corresponding to a provincial mean annual age- and sex-adjusted incidence rate of 2.13 cases per 100,000. Children under five years of age had the highest incidence of disease. Males had a higher incidence than females, except for those 15-19 years of age. Five percent of cases were reported as HIV-positive or having AIDS. The proportion of cases occurring between July and November inclusive (63%) was significantly higher than expected (42%) assuming no seasonal variation (p < 0.01). The proportion of rural cases observed (29%) was significantly higher than expected (17%) based on the Ontario population (p < 0.01). Travel to or prior residence in an endemic area was identified in 22% of the cases where a risk setting was reported (n = 265).

Influence of age and normal plasma fibrinogen levels on flow-mediated dilation in healthy adults

This study examined the effects of age-associated increases in fibrinogen on brachial artery flow-mediated dilation in 30 healthy nonsmokers. The findings demonstrate an inverse association between normal plasma fibrinogen levels and vascular function (r = -0.56, p = 0.001), suggesting elevated plasma fibrinogen may decrease the artery's responsiveness to certain vasodilatory signals, such as shear stress.

Risk factors for acute diarrhoea among inhabitants of Kampala District, Uganda

OBJECTIVE

To identify modifiable individual and household risk factors for diarrhoea among people of all ages in Kampala district, Uganda.

DESIGN

A cross-sectional, analytical study.

SETTING

Multi-stage sampling. Four purposively selected parishes, two each from low and high socio-economic residential areas in Kampala district. Two randomly selected zones per parish with 60 households randomly selected from each zone.

STUDY GROUP

All members present in each household at time of study. Individual and household information collected by means of personal interview using a questionnaire.

MAIN OUTCOME MEASURES

Odds of diarrhoea among individuals or households exposed to a study factor compared with the odds of diarrhoea among those not exposed to the factor.

RESULTS

Drinking raw chicken eggs was significantly (P < 0.01) and strongly (odds ratio (OR) = 99) associated with diarrhoea among residents of Kampala district. The odds of diarrhoea in households that 'cooked just enough food per meal' was significantly less (OR = 0.42) than in those that did not. People who used municipal water supplies and those who boiled their drinking water were significantly less likely (OR = 0.27, OR = 0.33, respectively) than those who used other water sources and/or who did not boil drinking water to report an episode of diarrhoea in the 2 weeks preceding the survey. The odds of diarrhoea were 2.6 times greater for individuals who reported a pest problem than for those who did not, while keeping pets was found to be protective (OR = 0.43). The number of income earners was also significantly (P < 0.5) and negatively (OR = 0.59) associated with the occurrence of diarrhoea in a member of the household.

CONCLUSIONS

The findings of this study underscore the importance of proper food handling, preparation and eating habits as well as safe water, sanitation practices and socio-economic factors in the epidemiology of diarrhoea in developing countries.

A double-blind placebo controlled randomised trial of misoprostol and oxytocin in the management of the third stage of labour

OBJECTIVE

To compare oral misoprostol 400 microg with intramuscular oxytocin 10 IU in the routine management of the third stage.

DESIGN

Double-blind placebo controlled trial.

SETTING

Main referral hospital and its associated polyclinics in Accra, Ghana.

POPULATION

Four hundred and one low risk women, in the second stage of labour with anticipated vaginal delivery, who entered labour spontaneously.

METHODS

After delivery of the anterior shoulder of the baby, the women were randomised to receive either: 1. misoprostol 400 microg powder in water orally and 1 mL normal saline intramuscular injection (placebo); or 2. powdered cellulose in water orally (placebo) and 1 mL oxytocin 10 IU intramuscular injection.

MAIN OUTCOME MEASURES

Change in haemoglobin concentration from before delivery to 12 hours postpartum. Secondary outcomes included need for additional oxytocics, blood loss > 500 mL and > 1,000 mL, operative intervention for postpartum haemorrhage, and side effects, including nausea, vomiting, diarrhoea, shivering and elevated temperature.

RESULTS

Demographic characteristics were similar. There was no significant difference in change in haemoglobin concentration between the two groups (0.60 g/dL for misoprostol and 0.55 g/dL for oxytocin; relative difference 9.6%; 95% CI 20.5-39.6%; P = 0.54). There were no significant differences in secondary outcomes with the exception of shivering, which occurred more frequently in the misoprostol group (22.2% vs 5.7%; relative risk 4.73; 95% CI 2.31-9.68; P < 0.0001).

CONCLUSIONS

In low risk women oral misoprostol appears to be as effective in minimising blood loss in the third stage of labour as intramuscular oxytocin. Shivering was noted more frequently with misoprostol use, but no other side effects were noted. Misoprostol has great potential for use in the third stage of labour especially in developing countries.

Estimation of the under-reporting rate for the surveillance of Escherichia coli O157:H7 cases in Ontario, Canada

Two models estimating the proportion of Escherichia coli O157:H7 cases not reported in the Ontario notifiable diseases surveillance system are described. The first model is a linear series of adjustments in which the total number of reported cases is corrected by successive underreporting coefficients. The structure of the second model is based on a relative difference in the proportion of E. coli O157:H7 cases which are hospitalized between the surveillance database and the underlying population. Based on this analysis, the rate of under-reporting of symptomatic cases of E. coli O157:H7 infection in Ontario ranges from 78 to 88% corresponding to a ratio of 1 reported case for approximately 4-8 symptomatic cases missed by the surveillance system. This study highlights the need to increase awareness among public health workers of the potential biases that may exist in the interpretation of routine surveillance data.

Uterine perforation from induced abortion at Korle Bu Teaching Hospital, Accra, Ghana: a five year review

A total of 79 cases of perforated uterus from termination of pregnancy in Accra, an incidence of 3.6% of induced abortion were managed at Korle Bu Teaching Hospital during the period 1990-1994. The mean age and parity of patients who had perforated uterus were 21.6 +/- 2.3 years and 1.97 +/- 0.28 respectively. The specific case mortality associated with this calamity was 227.8 per 1000. The need to prevent unwanted pregnancies through improved contraceptive measures and sex education must be emphasised in developing countries.

A descriptive study of the frequency and characteristics of proliferative enteropathy in swine in Ontario by analyzing routine animal health surveillance data

Routine surveillance data, collected on pathology submissions at the Animal Health Laboratory in Guelph between 1992 and 1997, were analyzed to determine demographic, clinical, and pathologic characteristics of cases of proliferative enteropathy and the frequency of this condition relative to other infectious enteric diseases in swine in Ontario. The most commonly reported disease was Escherichia coli enteritis (average cases/year = 70.0). Among infectious enteropathies that occur typically in neonatal pigs, coccidiosis (28.4 cases/year) and rotaviral enteritis (5.6 cases/year) were reported. Among infectious enteropathies generally associated with diarrhea in weaner and grower/finisher pigs, the most frequently reported was proliferative enteropathy (27.6 cases/year), followed by swine dysentery (23.3 cases/year), transmissible gastroenteritis (19.6 cases/year), and salmonellosis (8.4 cases/year). Diarrhea and bloody diarrhea were reported in 29% and 31%, respectively, of herds diagnosed with proliferative enteropathy. Important gross intestinal lesions included mucosal hypertrophy (62% of cases), hemorrhage (47%), and mucosal necrosis (34%). Histologic intestinal lesions included epithelial hyperplasia (90% of cases), mucosal necrosis (59%), and inflammation (49%). Our results suggest that proliferative enteropathy is a major infectious enteric disease in grower/finisher pigs in Ontario.

The relationship between E. coli indicator bacteria in well-water and gastrointestinal illnesses in rural families

OBJECTIVES

To determine the relationship between consumption of E. coli contaminated well-water and gastrointestinal illness in rural families.

METHODS

One hundred and eighty-one families with well-water as a drinking source participated in a one-year follow-up study. Water was tested for E. coli bacteria and health outcomes were monitored for house-hold members.

RESULTS

E. coli in well-water was significantly associated with gastrointestinal illness in family members, however the relationship was modified by the distance from the septic tank to the well. E. coli had an odds ratio of 2.16 [95% CI 1.04, 4.42] if the septic tank was greater than 20 metres from the well and 0.46 [95% CI 0.07, 2.95] if the septic tank was within 20 metres.

CONCLUSIONS

Consumption of contaminated well-water is associated with gastrointestinal illness. E. coli can be a useful marker for detecting wells that pose a potential public health problem in rural areas.

Pre-slaughter control of Escherichia coli O157 in beef cattle: a simulation study

A stochastic simulation model was used to assess the benefit of measures implemented in the pre-slaughter period that are aimed at reducing the contamination of beef carcasses with Shiga-like-toxin-producing Escherichia coli O157. The scenario studied was based on an abattoir processing approximately 1000 head of lot-fed cattle per day. Input assumptions were described using probability distributions to reflect uncertainty in their true values. Control measures that were assessed were based on either a reduction in herd prevalence of infection, reduction in opportunity for cross-contamination in the processing plant by re-ordering of the slaughter queue, reduction of concentration of E. coli O157 in fresh faeces, or a reduction in the amount of faeces, mud and bedding ('tag') transferred from the hide to the carcass. Some control measures evaluated were hypothetical in nature and were included to assist with the planning of research priorities. Simulations suggested that the greatest potential impact is associated with vaccination and with an agent that reduces shedding E. coli O157 in faeces. Knowledge of herd-test results obtained by testing a sample of animals from the herd provides only a minor advantage in control programmes, although application of a rapid test to all animals in all lots might be of some benefit. Under most scenarios, there is ample opportunity for cross-contamination to occur within the slaughter plant as a result of early entry of cattle contaminated with E. coli O157. An industry-wide reduction in the amount of tag attached to hides and addition of a source of cattle having a prolonged average fasting time were not predicted to have a large impact on mean amount of carcass contamination with E. coli O157.

A simulation model for studying the role of pre-slaughter factors on the exposure of beef carcasses to human microbial hazards

A Monte Carlo simulation model was constructed for assessing the quantity of microbial hazards deposited on cattle carcasses under different pre-slaughter management regimens. The model permits comparison of industry-wide and abattoir-based mitigation strategies and is suitable for studying pathogens such as Escherichia coli O157:H7 and Salmonella spp. Simulations are based on a hierarchical model structure that mimics important aspects of the cattle population prior to slaughter. Stochastic inputs were included so that uncertainty about important input assumptions (such as prevalence of a human pathogen in the live cattle-population) would be reflected in model output. Control options were built into the model to assess the benefit of having prior knowledge of animal or herd-of-origin pathogen status (obtained from the use of a diagnostic test). Similarly, a facility was included for assessing the benefit of re-ordering the slaughter sequence based on the extent of external faecal contamination. Model outputs were designed to evaluate the performance of an abattoir in a 1-day period and included outcomes such as the proportion of carcasses contaminated with a pathogen, the daily mean and selected percentiles of pathogen counts per carcass, and the position of the first infected animal in the slaughter run. A measure of the time rate of introduction of pathogen into the abattoir was provided by assessing the median, 5th percentile, and 95th percentile cumulative pathogen counts at 10 equidistant points within the slaughter run. Outputs can be graphically displayed as frequency distributions, probability densities, cumulative distributions or x-y plots. The model shows promise as an inexpensive method for evaluating pathogen control strategies such as those forming part of a Hazard Analysis and Critical Control Point (HACCP) system.

The relationship between E. coli indicator bacteria in well-water and gastrointestinal illnesses in rural families

OBJECTIVES

To determine the relationship between consumption of E. coli contaminated well-water and gastrointestinal illness in rural families.

METHODS

One hundred and eighty-one families with well-water as a drinking source participated in a one-year follow-up study. Water was tested for E. coli bacteria and health outcomes were monitored for house-hold members.

RESULTS

E. coli in well-water was significantly associated with gastrointestinal illness in family members, however the relationship was modified by the distance from the septic tank to the well. E. coli had an odds ratio of 2.16 [95% CI 1.04, 4.42] if the septic tank was greater than 20 metres from the well and 0.46 [95% CI 0.07, 2.95] if the septic tank was within 20 metres.

CONCLUSIONS

Consumption of contaminated well-water is associated with gastrointestinal illness. E. coli can be a useful marker for detecting wells that pose a potential public health problem in rural areas.

Reliability of an ordinal rating system for assessing the amount of mud and feces (tag) on cattle hides at slaughter

A study was conducted to provide a quantitative description of the amount of tag (mud, soil, and bedding) adhered to the hides of feedlot beef cattle and to appraise the statistical reliability of a subjective rating system for assessing this trait. Initially, a single rater obtained baseline data by assessing 2,417 cattle for 1 month at an Ontario beef processing plant. Analysis revealed that there was a strong tendency for animals within sale-lots to have a similar total tag score (intralot correlation = 0.42). Baseline data were summarized by fitting a linear model describing an individual's total tag score as the sum of their lot mean tag score (LMTS) plus an amount representing normal variation within the lot. LMTSs predicted by the linear model were adequately described by a beta distribution with parameters nu = 3.12 and omega = 5.82 scaled to fit on the 0-to-9 interval. Five raters, trained in use of the tag scoring system, made 1,334 tag score observations in a commercial abattoir, allowing reliability to be assessed at the individual level and at the lot level. High values for reliability were obtained for individual total tag score (0.84) and lot total tag score (0.83); these values suggest that the tag scoring system could be used in the marketing and slaughter of Ontario beef cattle to improve the cleanliness of animals presented for slaughter in an effort to control the entry of microbial contamination into abattoirs. Implications for the use of the tag scoring system in research are discussed.

Temporal and geographical distributions of reported cases of Escherichia coli O157:H7 infection in Ontario

The distribution of 3001 cases of verocytotoxigenic Escherichia coli (VTEC) reported in the Province of Ontario, Canada, were examined to describe the magnitude of this condition geographically and to evaluate the spatial relationship between livestock density and human VTEC incidence using a Geographical Information System. Incidence of VTEC cases had a marked seasonal pattern with peaks in July. Areas with a relatively high incidence of VTEC cases were situated predominantly in areas of mixed agriculture. Spatial models indicated that cattle density had a positive and significant association with VTEC incidence of reported cases (P = 0.000). An elevated risk of VTEC infection in a rural population could be associated with living in areas with high cattle density. Results of this study suggested that the importance of contact with cattle and the consumption of contaminated well water or locally produced food products may have been previously underestimated as risk factors for this condition.

Antenatal haemoglobin profile at Korle-Bu Teaching Hospital

OBJECTIVE

To determine the frequency of haemoglobin (Hb) measurement and some socio-demographic characteristics in women attending antenatal clinic.

DESIGN

Prospective cross-sectional study.

SETTING

Antenatal clinic, Korle-Bu Teaching Hospital.

SUBJECTS

Nine hundred and thirty two pregnant mothers attending antenatal clinic at the hospital. Patients with sickle cell disease, thalassaemia, sickling test positive or unknown sickling status were excluded.

MAIN OUTCOME MEASURES

Proportion of patients whose records showed various frequencies of Hb determinations and the proportion of those with anaemia at 26 weeks and 34 weeks gestations.

RESULTS

One hundred and seventy five (18.8%) patients did not have antenatal Hb measurement; 248 (26.6%) had two, and 251 (26.9%) had more than two measurements. The mean of booking Hb was 10.6 + 1.53 gm/dl. Of the 458 subjects with reliable dates, 293 had their booking Hb measurement at < 26 weeks. For this sub-group the mean was 10.8 +/- 1.43 gm/dl. (22.5% were < 10 gm/dl). For 272 subjects with reliable dates whose last Hb measurement was at > 34 weeks, the mean last Hb was 11.0 +/- 1.37 gm/dl. (last Hb was < 10 gm/dl in 19.1%). Nulliparity and booking antenatal weight < 64.0 kg were significantly associated with Hb < 10 gm/dl at some time during pregnancy.

CONCLUSION

Anaemia in pregnancy is common in this urban population. Combined effects of iron-folate supplementation, malaria chemoprophylaxis as well as early booking and a waiver of antenatal care user fees for needy patients are suggested as remedial measures.

Associations between virulence factors of Shiga toxin-producing Escherichia coli and disease in humans

Associations between known or putative virulence factors of Shiga toxin-producing Escherichia coli and disease in humans were investigated. Univariate analysis and multivariate logistic regression analysis of a set of 237 isolates from 118 serotypes showed significant associations between the presence of genes for intimin (eae) and Shiga toxin 2 (stx2) and isolates from serotypes reported in humans. Similar associations were found with isolates from serotypes reported in hemorrhagic colitis and hemolytic-uremic syndrome. The enterohemorrhagic E. coli (EHEC) hemolysin gene was significantly associated with isolates from serotypes found in severe diseases in univariate analysis but not in multivariate logistic regression models. A strong association between the intimin and EHEC-hemolysin genes may explain the lack of statistical significance of EHEC hemolysin in these multivariate models, but a true lack of biological significance of the hemolysin in humans or in disease cannot be excluded. This result warrants further investigations of this topic. Multivariate analysis revealed an interaction between the eae and stx2 genes, thus supporting the hypothesis of the synergism between the adhesin intimin and Shiga toxin 2. A strong statistical association was observed between the stx2 gene and severity of disease for a set of 112 human isolates from eight major serotypes. A comparison of 77 isolates of bovine origin and 91 human isolates belonging to six major serotypes showed significant associations of the genes for Shiga toxin 1 and EspP protease with bovine isolates and an increased adherence on HEp-2 cell cultures for human isolates, particularly from diarrheic patients and healthy persons.

Hb Hammersmith [beta 42(CD1) Phe-->Ser]: occurrence as a de novo mutation in black monozygotic twins with multiple congenital anomalies

PURPOSE

To present the occurrence of Hb Hammersmith as a de novo mutation in African-American twins with multiple congenital anomalies.

METHODS

Standard hematologic methods were used. The presence of an unstable Hb variant was confirmed by brilliant cresyl blue staining and an isopropanol stability test. Hb Hammersmith was confirmed by the sequencing of polymerase chain reaction-amplified beta-globin gene.

RESULTS

The presence of Hb Hammersmith was confirmed in female monozygotic twins of African-American origin with congenital Heinz body hemolytic anemia and multiple congenital anomalies. The variant occurred as a de novo mutation in the twins.

CONCLUSION

This report describes the occurrence of Hb Hammersmith [B42(CD1)Phe-->Ser] in African-American twins. As with the other reported cases, both twins were female. In addition to Heinz body hemolytic anemia, a low arterial O2 saturation in the proposita was shown by pulse oximetry. Multiple congenital anomalies involving various systems were also found in both twins.

Murine CASK is disrupted in a sex-linked cleft palate mouse mutant

A transgenic mouse insertional mutant displayed the phenotype of altered cranial morphology with sex-linked cleft palate. We have cloned the disrupted genomic X-linked locus and report the identification of the mCASK gene. The gene is transcribed to produce two messages of 4.5 and 9.5 kb expressed during development and in adult tissues, particularly the brain. We describe the isolation of two differentially spliced mouse cDNAs from the locus (mCASK-A and mCASK-B). The mCASK-B cDNA probably represents the full-length product of the 4.5-kb transcript. The identical N-termini of the predicted encoded proteins (mCASK-A and -B) are highly homologous to Ca2+/calmodulin-dependent protein kinase II, while the deduced C-terminus of mCASK-B is highly homologous to a family of multidomain proteins containing a guanylate kinase motif, the MAGUK proteins. mCASK-B is a new member of an emerging family of genes in which the encoded proteins combine these domains, termed here, the CAMGUKs, including rat CASK, Caenorhabditis elegans lin-2, and Drosophila caki/camguk. The CAMGUKs are likely to be effectors in signal transduction as regulatory partners of transmembrane molecules, modulated by calcium and nucleotides. The transgene in this mutant mouse line integrated into an intron that bisects the encoded calmodulin-binding domain, a potentially important regulatory domain of the predicted protein, generating hybrid transcripts.