Fusarium genomic resources: tools to limit crop diseases and mycotoxin contamination

It has been almost 10 years since Joan Bennett suggested that fungal biologists create a "wish list" for fungal genome sequences (Bennett JW. White paper: Genomics for filamentous fungi. Fungal Genet Biol 1997; 21: 3-7). The availability of over 200 review papers concerning fungal genomics is a reflection of significant progress with a diversity of fungal species. Although much progress has been made, the use of genomic data to study mycotoxin synthesis and function, pathogenesis and other aspects of fungal biology is in its infancy. Here, we briefly present the status of publicly available genomic resources for Fusarium, a genus of important plant pathogenic and mycotoxin-producing fungi of worldwide concern. Preliminary examination of microarray data collected from F. verticillioides liquid cultures provides evidence of widespread differential gene expression over time.

Functional analysis of the polyketide synthase genes in the filamentous fungus Gibberella zeae (anamorph Fusarium graminearum)

Polyketides are a class of secondary metabolites that exhibit a vast diversity of form and function. In fungi, these compounds are produced by large, multidomain enzymes classified as type I polyketide synthases (PKSs). In this study we identified and functionally disrupted 15 PKS genes from the genome of the filamentous fungus Gibberella zeae. Five of these genes are responsible for producing the mycotoxins zearalenone, aurofusarin, and fusarin C and the black perithecial pigment. A comprehensive expression analysis of the 15 genes revealed diverse expression patterns during grain colonization, plant colonization, sexual development, and mycelial growth. Expression of one of the PKS genes was not detected under any of 18 conditions tested. This is the first study to genetically characterize a complete set of PKS genes from a single organism.

Fusarium graminearum TRI14 is required for high virulence and DON production on wheat but not for DON synthesis in vitro

Fusarium head blight (FHB) of wheat (Triticum aestivum L.), caused by the fungus Fusarium graminearum, is a major concern worldwide. FHB grain is reduced in yield, may fail to germinate, and is often contaminated with deoxynivalenol, a trichothecene mycotoxin linked to a variety of animal diseases and feed refusals. Annual losses in the tens of millions of dollars due to FHB underscore the need to develop improved methods of disease control and prevention. Previous research has identified deoxynivalenol biosynthesis as a virulence factor on wheat. Recently, we found that the TRI14 gene of F. sporotrichioides, closely related to F. graminearum, was not required for synthesis of a related trichothecene, T-2 toxin. TRI14 does not share similarity with any previously described genes in the databases. In this study, we examined the role that F. graminearum TRI14 may play in both deoxynivalenol synthesis and in virulence on wheat. TRI14 deletion mutants synthesize deoxynivalenol on cracked maize kernel medium and exhibit wild-type colony morphology and growth rate on complex and minimal agar media. However, FHB assays on greenhouse-grown wheat indicate that FgDeltaTri14 mutants cause 50-80% less disease than wild type and do not produce a detectable quantity of deoxynivalenol on plants. We discuss a number of possible roles that TRI14 may play in the disease process.

Comparative analysis of 87,000 expressed sequence tags from the fumonisin-producing fungus Fusarium verticillioides

Fusarium verticillioides (teleomorph Gibberella moniliformis) is a pathogen of maize worldwide and produces fumonisins, a family of mycotoxins that have been associated with several animal diseases as well as cancer in humans. In this study, we sought to identify fungal genes that affect fumonisin production and/or the plant-fungal interaction. We generated over 87,000 expressed sequence tags from nine different cDNA libraries that correspond to 11,119 unique sequences and are estimated to represent 80% of the genomic complement of genes. A comparative analysis of the libraries showed that all 15 genes in the fumonisin gene cluster were differentially expressed. In addition, nine candidate fumonisin regulatory genes and a number of genes that may play a role in plant-fungal interaction were identified. Analysis of over 700 FUM gene transcripts from five different libraries provided evidence for transcripts with unspliced introns and spliced introns with alternative 3' splice sites. The abundance of the alternative splice forms and the frequency with which they were found for genes involved in the biosynthesis of a single family of metabolites as well as their differential expression suggest they may have a biological function. Finally, analysis of an EST that aligns to genomic sequence between FUM12 and FUM13 provided evidence for a previously unidentified gene (FUM20) in the FUM gene cluster.

National survey of diagnostic services for genital herpes

OBJECTIVE

To investigate the provision of diagnostic services for genital herpes simplex virus (HSV) infection in the United Kingdom.

METHODS

National survey of laboratories providing diagnostic services for genital herpes.

RESULTS

Completed questionnaires were returned from 25/32 (78%) laboratories participating in the Clinical Virology Network, including seven in London, 12 in the rest of England, one in Wales, four in Scotland, and one in Northern Ireland. Virus culture was the diagnostic method of choice in 20/25 (80%) laboratories; 5/25 (20%) routinely used HSV DNA detection by polymerase chain reaction (PCR). HSV PCR for DNA detection in cerebrospinal fluid (CSF) was available in 17/25 (68%) laboratories. Typing of isolates (HSV-1 or HSV-2) was performed routinely in 22/25 (88%) laboratories. Only 2/25 (8%) laboratories offered HSV type specific serology, although an additional 12/25 (48%) referred requests elsewhere. Consistent with this finding, the number of HSV type specific antibody tests referred to the Health Protection Agency increased by nearly fivefold between 1997 and 2003.

CONCLUSIONS

Virus culture remains the preferred diagnostic method for genital herpes, despite evidence indicating that its sensitivity is suboptimal compared to PCR. As HSV PCR is widely available for testing of CSF, it is recommended that clinicians and virologists discuss ways to implement PCR testing of genital swabs, thus enabling greater diagnostic accuracy. A call is made for studies to assess the use of HSV type specific serology in genitourinary medicine (GUM) settings, now that rapid and validated assays have become available and guidelines have been issues to provide recommendations on their use.

Discontinuous distribution of fumonisin biosynthetic genes in the Gibberella fujikuroi species complex

Production of the carcinogenic mycotoxins fumonisins has been reported in several Fusarium species, most of which are members of the Gibberella fujikuroi (Gf) complex. In this study, we examined 15 Fusarium species in the Gf complex and 12 other species for fumonisin production and the presence of fumonisin biosynthetic genes (FUM). Among the species within the Gf complex, fumonisin production was detected only in F. fujikuroi, F. globosum, F. proliferatum, F. nygamai, F. oxysporum and F. verticillioides. These five species include members of two of the three major clades delineated in the Gf complex. The FUM genes were detected in these same five species and in F. anthophilum, a member of the third clade. Among the species outside the Gf complex, fumonisin production and FUM genes were detected only in F. oxysporum. Phylogenetic analyses of nucleotide sequences from two FUM gene fragments inferred relationships similar but not identical to those inferred from previous analyses of other genes. The results indicate the FUM genes are discontinuously distributed in the Gf complex and that this distribution gives rise to the differences in the abilities of closely related Fusarium species to produce fumonisins.

Patterns of trichothecene production, genetic variability, and virulence to wheat of Fusarium graminearum from smallholder farms in Nepal

Fusarium graminearum causes wheat head blight and contaminates grain with the trichothecenes 4-deoxynivalenol and nivalenol. Sequence analysis of trichothecene genes indicates that nivalenol production is the ancestral trait; however, deoxynivalenol producers occur worldwide and predominate in North and South America and in Europe. Analysis of a large field population (>500 strains) from Nepal identified three groups that were both genetically distinct and polymorphic for trichothecene production: SCAR1 comprising 95% deoxynivalenol producers, SCAR2 comprising 94% nivalenol producers, and SCAR3/5 comprising 34% deoxynivalenol producers/63% nivalenol producers. The ability to cause wheat head blight differed between SCAR groups and trichothecene chemotypes: deoxynivalenol producers were more virulent than nivalenol producers across all three SCAR groups and within the SCAR3/5 genetic background. These data support the hypothesis that production of deoxynivalenol rather than nivalenol confers a selective advantage to this important wheat pathogen.

Functional demarcation of the Fusarium core trichothecene gene cluster

Many Fusarium species produce toxic sesquiterpenoids known as trichothecenes, including deoxynivalenol and nivalenol by Fusarium graminearum and T-2 toxin by Fusarium sporotrichioides. These toxins are potent inhibitors of protein synthesis and are a significant agricultural problem due to their adverse affect on human, animal, and plant health. Previously, 10-12 co-regulated orthologous genes within a 26-kb region were identified in F. graminearum and F. sporotrichioides, respectively. A majority of these clustered genes have been shown to be involved in different aspects of trichothecene metabolism including 7 of 15 biosynthetic steps. Three other biosynthetic steps are carried out by genes located elsewhere in the genome. In this study, we sequenced 14-16 kb of DNA on both sides of the core clusters and identified 12 new ORFs in both Fusarium species. Although the predicted functions of some of the new ORFs are consistent with some unassigned biochemical reactions, gene expression and gene deletion studies indicate that none are required for trichothecene biosynthesis. These results provide evidence to demarcate both ends of the core trichothecene gene cluster. Index descriptors: Fungal secondary metabolite, Pathogenic fungi, Gene cluster, Fusarium, Trichothecene, DON

Deletion and complementation of the mating type (MAT) locus of the wheat head blight pathogen Gibberella zeae

Gibberella zeae, a self-fertile, haploid filamentous ascomycete, causes serious epidemics of wheat (Triticum aestivum) head blight worldwide and contaminates grain with trichothecene mycotoxins. Anecdotal evidence dating back to the late 19th century indicates that G. zeae ascospores (sexual spores) are a more important inoculum source than are macroconidia (asexual spores), although the fungus can produce both during wheat head blight epidemics. To develop fungal strains to test this hypothesis, the entire mating type (MAT1) locus was deleted from a self-fertile (MAT1-1/MAT1-2), virulent, trichothecene-producing wild-type strain of G. zeae. The resulting MAT deletion (mat1-1/mat1-2) strains were unable to produce perithecia or ascospores and appeared to be unable to mate with the fertile strain from which they were derived. Complementation of a MAT deletion strain by transformation with a copy of the entire MAT locus resulted in recovery of production of perithecia and ascospores. MAT deletion strains and MAT-complemented strains retained the ability to produce macroconidia that could cause head blight, as assessed by direct injection into wheat heads in greenhouse tests. Availability of MAT-null and MAT-complemented strains provides a means to determine the importance of ascospores in the biology of G. zeae and perhaps to identify novel approaches to control wheat head blight.

Characterization of a fusarium 2-gene cluster involved in trichothecene C-8 modification

The Fusarium trichothecenes T-2 toxin and deoxynivalenol (DON) are potent inhibitors of eukaryotic protein synthesis and are a significant agricultural problem. Three coregulated loci are required for T-2 toxin synthesis by Fusarium sporotrichioides. The core-trichothecene gene cluster consists of 12 genes (Tri3-Tri14) while the second locus consists of a single gene (Tri101). The third locus was recently partially described and encodes 1-2 biosynthetic enzymes and a putative regulatory gene. Here, we describe a detailed characterization of this locus. Located adjacent to Tri1 is Tri16, which is required for esterification of the C-8 hydroxyl. A putative regulatory gene, also adjacent to Tri1, is not required for T-2 toxin synthesis. The genomic sequence of Fusarium graminearum (a DON producer) contains a putative functional Tri1 and a nonfunctional Tri16. The presence of the Tri16 pseudogene is consistent with the chemical structure of DON, which has a C-8 keto group rather than the C-8 ester of T-2 toxin.

Seroepidemiological study of herpes simplex virus types 1 and 2 in Brazil, Estonia, India, Morocco, and Sri Lanka

BACKGROUND

The association between herpes simplex virus type 2 (HSV-2) and human immunodeficiency virus (HIV) and the development of HSV vaccines have increased interest in the study of HSV epidemiology.

OBJECTIVES

To estimate the age and sex specific seroprevalence of HSV-1 and HSV-2 infections in selected populations in Brazil, Estonia, India, Morocco, and Sri Lanka.

METHODS

Serum samples were collected from various populations including children, antenatal clinic attenders, blood donors, hospital inpatients, and HIV sentinel surveillance groups. STD clinic attenders were enrolled in Sri Lanka, male military personnel in Morocco. Sera were tested using a common algorithm by type specific HSV-1 and HSV-2 antibody assay.

RESULTS

13,986 samples were tested, 45.0% from adult females, 32.7% from adult males, and 22.3% from children. The prevalence of HSV-1 varied by site ranging from 78.5%-93.6% in adult males and from 75.5%-97.8% in adult females. In all countries HSV-1 seroprevalence increased significantly with age (p<0.001) in both men and women. The prevalence of HSV-2 infection varied between sites. Brazil had the highest age specific rates of infection for both men and women, followed by Sri Lanka for men and Estonia for women, the lowest rates being found in Estonia for men and India for women. In all countries, HSV-2 seroprevalence increased significantly with age (p<0.01) and adult females had higher rates of infection than adult males by age of infection.

CONCLUSIONS

HSV-1 and HSV-2 seroprevalence was consistently higher in women than men, particularly for HSV-2. Population based data on HSV-1 and HSV-2 will be useful for designing potential HSV-2 vaccination strategies and for focusing prevention efforts for HSV-1 and HSV-2 infection.

Co-expression of 15 contiguous genes delineates a fumonisin biosynthetic gene cluster in Gibberella moniliformis

Fumonisins are mycotoxins produced by the maize pathogen Gibberella moniliformis and are associated with cancer in rodents. In this study, we determined the nucleotide sequence of a 75-kb region of G. moniliformis DNA and identified 18 heretofore undescribed genes flanking a cluster of five previously identified fumonisin biosynthetic (FUM) genes. Ten of the newly identified genes downstream of the cluster were coregulated with FUM genes and exhibited patterns of expression that were correlated with fumonisin production. BLASTX analyses indicated that the predicted functions of proteins encoded by the 10 genes were consistent with activities expected for fumonisin biosynthesis or self-protection. These data indicate that the 10 newly identified genes and the previously identified FUM genes constitute a fumonisin biosynthetic gene cluster. Disruption of two of the new genes, encoding longevity assurance factors, had no apparent effect on fumonisin production, but disruption of a third, encoding an ABC transporter, had a subtle effect on ratios of fumonisins produced.

Inactivation of a cytochrome P-450 is a determinant of trichothecene diversity in Fusarium species

Species of the genus Fusarium produce a great diversity of agriculturally important trichothecene toxins that differ from each other in their pattern of oxygenation and esterification. T-2 toxin, produced by Fusarium sporotrichioides, and nivalenol (NIV), produced by some strains of F. graminearum, contain an oxygen at the C-4 position. Deoxynivalenol (DON), produced by other strains of F. graminearum, lacks a C-4 oxygen. NIV and DON are identical except for this difference, whereas T-2 differs from these trichothecenes at three other carbon positions. Sequence and Northern analyses of the F. sporotrichioides genomic region upstream of the previously described core trichothecene gene cluster have extended the cluster by two genes: TRI13 and TRI14. TRI13 shares significant similarity with the cytochrome P-450 class of enzymes, but TRI14 does not share similarity with any previously characterized proteins. Gene disruption and fermentation studies in F. sporotrichioides indicate that TRI13 is required for the addition of the C-4 oxygen of T-2 toxin, but that TRI14 is not required for trichothecene biosynthesis. PCR and sequence analyses indicate that the TRI13 homolog is functional in NIV-producing strains of F. graminearum but nonfunctional in DON-producing strains of the fungus. These genetic observations are consistent with chemical observations that biosynthesis of T-2 toxin and NIV requires a C-4 hydroxylase while biosynthesis of DON does not.

Human caliciviruses in Europe

Caliciviruses are single-stranded RNA viruses, which are divided into four genera based on their morphology and genomic structure. Viruses from two genera, the Norwalk like viruses and Sapporo like viruses, are a common cause of acute, nonbacterial gastroenteritis in humans. Although the first human calicivirus discovered nearly 30 years ago, much of the epidemiological and biological character of these viruses is only now beginning to unfold. Investigation has been difficult due to a number of factors, the viruses cannot be amplified by in vitro cell culture or animal models and electron microscopy (EM) is often not sensitive enough to detect the viruses in stool samples. Recent advances in molecular diagnostic techniques and the advent of a baculovirus expression system have highlighted the clinical and public health importance of calicivirus in all age groups, their ability to cause infection via a number of transmission routes as well as their considerable genetic diversity. These characteristics, in conjunction with the inability of humans to develop long-term immunity make HuCV an important public health issue in Europe and worldwide.

Immunogenicity of second dose measles-mumps-rubella (MMR) vaccine and implications for serosurveillance

Measles and mumps, but not rubella, outbreaks have been reported amongst populations highly vaccinated with a single dose of measles-mumps-rubella (MMR) vaccine. Repeated experience has shown that a two-dose regime of measles vaccine is required to eliminate measles. This paper reports the effect of the first and second MMR doses on specific antibody levels in a variety of populations.2-4 years after receiving a first dose of MMR vaccine at age 12-18 months, it was found that a large proportion of pre-school children had measles (19.5%) and mumps (23.4%) IgG antibody below the putative level of protection. Only a small proportion (4.6%) had rubella antibody below the putative protective level. A total of 41% had negative or equivocal levels to one or more antigens. The proportion measles antibody negative (but not rubella or mumps) was significantly higher in children vaccinated at 12 months of age than at 13-17 months. There was no evidence for correlation of seropositivity to each antigen, other than that produced by a small excess of children (1%) negative to all three antigens. After a second dose of MMR, the proportion negative to one or more antigens dropped to <4%. Examination of national serosurveillance data, found that following an MR vaccine campaign in cohorts that previously received MMR, both measles and rubella antibody levels were initially boosted but declined to pre-vaccination levels within 3 years. Our study supports the policy of administering a second dose of MMR vaccine to all children. However, continued monitoring of long-term population protection will be required and this study suggests that in highly vaccinated populations, total measles (and rubella) IgG antibody levels may not be an accurate reflection of protection. Further studies including qualitative measures, such as avidity, in different populations are merited and may contribute to the understanding of MMR population protection.

Disparities in cholesterol screening: falling short of a national health objective

BACKGROUND

The objective of this study was to determine whether the Year 2000 national health objective for cholesterol screening was attained and to identify disparities in cholesterol screening across racial or ethnic and socioeconomic groups.

METHODS

Using data from 149,692 persons interviewed by the 1999 Behavioral Risk Factor Surveillance System, we estimated the proportion of adults age > or =20 years who were screened for high blood cholesterol within the preceding 5 years.

RESULTS

Overall, an estimated 70.8% of the U.S. population was screened for cholesterol, falling short of the Year 2000 objective of 75%. Screening prevalence was lowest at ages 20-44 years (58.2%), in contrast to ages 45-64 years (81.9%) and > or =65 years (87.1%). Screening prevalence was also low among Asian or Pacific Islanders (62.7%) and Hispanics (60.7%), particularly Hispanic men (55.3%). After multivariate adjustment, Asian Pacific Islanders were significantly less likely to be screened compared with white non-Hispanics (OR = 0.76, 95% CI 0.65, 0.89). The likelihood of screening decreased with decreasing income level (P < 0.05) and persons with health insurance were 1.6 times more likely to have been screened during the past 5 years than adults with no insurance (P < 0.05).

CONCLUSIONS

Significant disparities in cholesterol screening exist across age, gender, racial or ethnic, and socioeconomic groups in the United States. As we look to attain the objectives of Healthy People 2010, state and local health officials and policy makers should be aware of these disparities in order to design and target effective cholesterol screening programs and cardiovascular disease prevention programs to those most in need.

The aetiology of maculopapular rash diseases in Niterói, State of Rio de Janeiro, Brazil: implications for measles surveillance

A study investigating the causes of rash diseases using systematic laboratory testing was conducted in Niterói, Rio de Janeiro, between January 1994 to April 1998. Sera from 327 patients were tested for evidence of anti-rubella virus, measles virus, human parvovirus B19 and dengue fever virus specific immunoglobulin IgM and anti-human herpes virus type 6 (HHV-6) IgG antibodies. A laboratory confirmed diagnosis was achieved in 71.3% of the cases investigated: dengue fever (33.0%), rubella (20.2%), parvovirus B19 (9.2%), measles (6.7%) and HHV-6 (2.1%). No diagnosis was established for 94 cases (28.7%). An outbreak of measles was detected during 1997, with a peak in September and October. All of the diseases studied here presented with clinical features similar to measles and classical symptoms were found in all measles confirmed cases. The large overlap of combinations of signs and symptoms seen in this study highlights the difficulties of diagnosing a rash illness on clinical grounds alone.

Hematocrit and the risk of coronary heart disease mortality

BACKGROUND

An association between hematocrit (Hct) and coronary heart disease (CHD) mortality has been previously observed. However, the relationship of Hct and CHD independent of other cardiovascular disease (CVD) risk factors and differences between men and women remain unclear.

METHODS

We examined the association between Hct and CHD mortality with Cox regression analyses of data from 8896 adults, aged 30-75 years, in the Second National Health and Nutrition Examination Survey (NHANES II) Mortality Study (1976-1992). Covariates included age, sex, race, education, smoking status, hypertensive status, total serum cholesterol, body mass index, white blood cell count, and history of CVD and diabetes. Hct was categorized by use of sex-specific tertiles, and all analyses were stratified by sex.

RESULTS

During 16.8 years of follow-up, there were 545 (men 343, women 202) deaths from CHD (International Classification of Diseases, 9th revision [ICD-9] 410-414), 778 (men 426, women 279) deaths from diseases of the heart (ICD-9 390-398, 402, 404, 410-414, 415-417, 420-429), and 2046 (men 1216, women 830) all-cause deaths. Among men, the crude CHD mortality rate per 10,000 population was 42.6, 31.9, and 46.3 among those with Hct in the lower, middle, and upper tertiles, respectively. The corresponding crude CHD mortality rates among women were 12.6, 18.6, and 27.7. After adjustment for age and other CVD risk factors, there was no association between Hct in the upper tertile compared with the lower tertile and mortality from either CHD, diseases of the heart, or all causes among men. Women with Hct in the upper tertile were 1.3 times (95% CI 0.9-1.9) more likely to die from CHD than were women with Hct in the lowest tertile, after multivariate adjustment. The effect of high Hct on CHD mortality among women younger than 65 years of age was slightly stronger (relative risk 2.2, 95% CI 1.0-4.6).

CONCLUSIONS

These results suggest that the association between Hct and mortality from CHD and all causes is complex, differing both by sex and age. Further research is needed to gain a better understanding of these age and sex differences.

Bile duct injury during laparoscopic cholecystectomy: results of a national survey

OBJECTIVE

To determine whether surgical residency training has influenced the occurrence of common bile duct injuries during laparoscopic cholecystectomy, and to asses the anatomic and technical details of bile duct injuries from the practices of surgeons trained in laparoscopic cholecystectomy after residency versus surgeons trained in laparoscopic cholecystectomy during residency.

SUMMARY BACKGROUND DATA

Shortly after the introduction of laparoscopic cholecystectomy, the rate of injury to the common bile duct increased to 0.5%, and injuries were more commonly reported early in each surgeon's experience. It is not known whether learning laparoscopic cholecystectomy during surgery residency influences this pattern.

METHODS

An anonymous questionnaire was mailed to 3,657 surgeons across the United States who completed an Accreditation Council for Graduate Medical Education (ACGME)-approved residency between 1980 and 1990 (group A) or 1992 and 1998 (group B). All surgeons in group A learned laparoscopic cholecystectomy after residency, and all those in group B learned laparoscopic cholecystectomy during residency. Information obtained included practice description, number of laparoscopic cholecystectomies completed since residency, postgraduate training in laparoscopy, and annual volume of laparoscopic cholecystectomy in the surgeon's hospital. In addition, technical details queried included the completion of a cholangiogram, the interval between injury and identification, the method of repair, and the site of definitive treatment. The primary endpoint was the occurrence of a major bile duct injury during laparoscopic cholecystectomy (bile leaks without a major bile duct injury were not tabulated).

RESULTS

Forty-five percent (n = 1,661) of the questionnaires were completed and returned. Mean practice experience was 13.6 years for group A and 5.4 years for group B. At least one injury occurrence was reported by 422 surgeons (37.6%) in group A and 143 surgeons (26.5%) in group B. Forty percent of the injuries in group A occurred during the first 50 cases compared with 22% in group B. Thirty percent of bile duct injuries in group A and 32.9% of all injuries in group B occurred after a surgeon had performed more than 200 laparoscopic cholecystectomies. Independent of the number of laparoscopic cholecystectomies completed since residency, group A surgeons were 39% more likely to report one or more biliary injuries and 58% more likely to report two or more injuries than their counterparts in group B. Bile duct injuries were more likely to be discovered during surgery if a cholangiogram was completed than if cholangiography was omitted (80.9% vs. 45.1%). Sixty-four percent of all major bile duct injuries required biliary reconstruction, and most injuries were definitively treated at the hospital where the injury occurred. Only 14.7% of injuries were referred to another center for repair.

CONCLUSIONS

Accepting that the survey bias underestimates the true frequency of bile duct injuries, residency training decreases the likelihood of injuring a bile duct, but only by decreasing the frequency of early "learning curve" injuries. If one accepts a liberal definition of the learning curve (200 cases), it appears that at least one third of injuries are not related to inexperience but may reflect fundamental errors in the technique of laparoscopic cholecystectomy as practiced by a broad population of surgeons in the United States. Intraoperative cholangiography is helpful for intraoperative discovery of injuries when they occur. Most injuries are repaired in the hospital where they occur and are not universally referred to tertiary care centers.

Measles virus strains circulating in Ethiopia in 1998-1999: molecular characterisation using oral fluid samples and identification of a new genotype

A measles outbreak in December 1998 in Bedelle (vaccine coverage <40%) and two sporadic cases in Addis Ababa, Ethiopia, were investigated. Paired serum and oral fluid samples were collected 2-8 days after the onset of symptoms. A total of 53 of 55 outbreak cases and both sporadic cases were positive for serum measles virus-specific IgM. Oral fluid measles-specific IgM was positive in 71% of cases collected up to 5 days after onset and in 90% collected at 6-8 days. By contrast, 100% of oral fluid samples were positive for measles virus RNA by RT-PCR, suggesting that early collection of samples favoured the detection of measles virus RNA by RT-PCR. The measles virus strain in the outbreak was identified as genotype D4. One strain from a sporadic case was also genotype D4; the strain from the other sporadic case was assigned to clade D but was distinct. The degree of divergence from recognised clade D strains suggested that, together with three strains from the United Kingdom, it represents an additional genotype of clade D (GenBank accession numbers AF280800-280807).

Distribution of rotavirus G and P types in north and south Indian children with acute diarrhoea in 1998-99

VP7 and VP4 genotypes of 82 rotavirus strains from children with acute diarrhoea during November 1998-January 1999, in 4 Indian towns, were determined by reverse-transcription PCR. Overall, 68/82 (83%) could be VP7- and 52/82 (63%) VP4-typed. Geographical differences in rotavirus circulation have implications for future vaccination strategies.

Impaired fasting glucose, diabetes mellitus, and cardiovascular disease risk factors are associated with prolonged QTc duration. Results from the Third National Health and Nutrition Examination Survey

BACKGROUND

Impaired glucose tolerance and diabetes mellitus have been associated with a prolonged QT interval among select populations. However, these associations remain unclear among the general population.

METHODS

We examined these relationships using data from 5833 adults aged 40-90 years from NHANES III (1988-1994). Univariate differences in cardiovascular disease (CVD) risk factors were examined across tertiles of heart rate corrected QT (QTc). The association between glucose intolerance, CVD risk factors and a prolonged QTc (> or = 0.440 s) was also assessed with logistic regression adjusting for age, race, gender, education, and heart rate.

RESULTS

Prolonged QTc was observed among 22.0% of persons with normal glucose tolerance (NGT), 29.9% of those with impaired fasting glucose (IFG), and among 42.2% of persons with diabetes. Hypertension, serum cholesterol, obesity, heart rate, and fasting C-peptide and serum insulin levels were associated with prolonged QTc (all: P < or = 0.05). After multivariate adjustment, persons with IFG were 1.2 times (95% CI=0.7-2.0) as likely and persons with diabetes 1.6 times (95% CI=1.1-2.3) as likely to have a prolonged QTc as persons with NGT. In addition, persons with diabetes and two or more additional CVD risk factors were 2.3 times (95% CI=1.3-4.0) as likely to have a prolonged QTc as persons with NGT and no CVD risk factors after multivariate adjustment.

CONCLUSION

Diabetes was associated with an increased likelihood of prolonged QTc independent of age, race, gender, education, and heart rate. In addition, persons with diabetes and multiple CVD risk factors were more likely to have a prolonged QTc than those with NGT and no additional risk factors, suggesting that these persons may be at increased risk for cardiac arrhythmia and sudden death.