South African guidelines on the determination of death

Summary

Death is a medical occurrence that has social, legal, religious and cultural consequences requiring common clinical standards for its diagnosis and legal regulation. This document compiled by the Critical Care Society of Southern Africa outlines the core standards for determination of death in the hospital context. It aligns with the latest evidence-based research and international guidelines and is applicable to the South African context and legal system. The aim is to provide clear medical standards for healthcare providers to follow in the determination of death, thereby promoting safe practices and high-quality care through the use of uniform standards. Adherence to such guidelines will provide assurance to medical staff, patients, their families and the South African public that the determination of death is always undertaken with diligence, integrity, respect and compassion, and is in accordance with accepted medical standards and latest scientific evidence. The consensus guidelines were compiled using the AGREE II checklist with an 18-member expert panel participating in a three-round modified Delphi process. Checklists and advice sheets were created to assist with application of these guidelines in the clinical environment (https://criticalcare.org.za/resource/death-determination-checklists/).

Key points

Brain death and circulatory death are the accepted terms for defining death in the hospital context.

Death determination is a clinical diagnosis which can be made with complete certainty provided that all preconditions are met.

The determination of death in children is held to the same standard as in adults but cannot be diagnosed in children <36 weeks’ corrected gestation.

Brain-death testing while on extra-corporeal membrane oxygenation is outlined.

Recommendations are given on handling family requests for accommodation and on consideration of the potential for organ donation.

The use of a checklist combined with a rigorous testing process, comprehensive documentation and adequate counselling of the family are core tenets of death determination. This is a standard of practice to which all clinicians should adhere in end-of-life care.

South African guidelines on the determination of death

Death is a medical occurrence that has social, legal, religious and cultural consequences requiring common clinical standards for its diagnosis and legal regulation. This document compiled by the Critical Care Society of Southern Africa outlines the core standards for determination of death in the hospital context. It aligns with the latest evidence-based research and international guidelines and is applicable to the South African context and legal system. The aim is to provide clear medical standards for healthcare providers to follow in the determination of death, thereby promoting safe practices and high-quality care through the use of uniform standards. Adherence to such guidelines will provide assurance to medical staff, patients, their families and the South African public that the determination of death is always undertaken with diligence, integrity, respect and compassion, and is in accordance with accepted medical standards and latest scientific evidence. The consensus guidelines were compiled using the AGREE II checklist with an 18-member expert panel participating in a three-round modified Delphi process. Checklists and advice sheets were created to assist with application of these guidelines in the clinical environment (https://criticalcare.org.za/resource/death-determination-checklists/). Key points • Brain death and circulatory death are the accepted terms for defining death in the hospital context. • Death determination is a clinical diagnosis which can be made with complete certainty provided that all preconditions are met. • The determination of death in children is held to the same standard as in adults but cannot be diagnosed in children <36 weeks' corrected gestation. • Brain-death testing while on extra-corporeal membrane oxygenation is outlined. • Recommendations are given on handling family requests for accommodation and on consideration of the potential for organ donation. • The use of a checklist combined with a rigorous testing process, comprehensive documentation and adequate counselling of the family are core tenets of death determination. This is a standard of practice to which all clinicians should adhere in end-of-life care.

Outpatient Treatment of Pulmonary Embolism with Dalteparin

Pulmonary embolism is a common complication of deep vein thrombosis. It has been established that low molecular weight heparin may be used to treat deep vein thrombosis or pulmonary embolism and randomized studies have established that outpatient management of deep vein thrombosis with low molecular weight heparin is at least as effective as in-hospital management with unfractionated heparin.

This was a prospective cohort study of eligible patients with pulmonary embolism managed as outpatients using dalteparin (200 U/kg s/c daily) for a minimum of five days and warfarin for 3 months. Outpatients included those managed exclusively out of hospital and those managed initially for 1-3 days as inpatients who then completed therapy o out of hospital. Reasons for admission included hemodynamic instability; hypoxia requiring oxygen therapy; admission for another medical reason; severe pain requiring parenteral analgesia or high risk of major bleeding. Patients were followed for three months for clinically apparent recurrent venous thromboembolism and bleeding.

Between three teaching hospitals, a total of 158 patients with pulmonary embolism were identified. Fifty patients were managed as inpatients and 108 as outpatients. Of the outpatients, 27 were managed for an average of 2.5 days as inpatients and then completed dalteparin therapy as outpatients. The remaining 81 patients were managed exclusively as outpatients with dalteparin. For all outpatients the overall symptomatic recurrence rate of venous thromboembolism was 5.6% (6/108) with only 1.9% (2/108) major bleeds. There were a total of four deaths with none due to pulmonary embolism or major bleed.

This prospective study suggests that outpatient management of pulmonary embolism is feasible and safe for the majority of patients.

A neurogenetic model for the study of schizophrenia spectrum disorders: the International 22q11.2 Deletion Syndrome Brain Behavior Consortium

Rare copy number variants contribute significantly to the risk for schizophrenia, with the 22q11.2 locus consistently implicated. Individuals with the 22q11.2 deletion syndrome (22q11DS) have an estimated 25-fold increased risk for schizophrenia spectrum disorders, compared to individuals in the general population. The International 22q11DS Brain Behavior Consortium is examining this highly informative neurogenetic syndrome phenotypically and genomically. Here we detail the procedures of the effort to characterize the neuropsychiatric and neurobehavioral phenotypes associated with 22q11DS, focusing on schizophrenia and subthreshold expression of psychosis. The genomic approach includes a combination of whole-genome sequencing and genome-wide microarray technologies, allowing the investigation of all possible DNA variation and gene pathways influencing the schizophrenia-relevant phenotypic expression. A phenotypically rich data set provides a psychiatrically well-characterized sample of unprecedented size (n=1616) that informs the neurobehavioral developmental course of 22q11DS. This combined set of phenotypic and genomic data will enable hypothesis testing to elucidate the mechanisms underlying the pathogenesis of schizophrenia spectrum disorders.

Acute viral bronchiolitis in South Africa: Diagnostic flow

Bronchiolitis may be diagnosed on the basis of clinical signs and symptoms. In a young child, the diagnosis can be made on the clinical pattern of wheezing and hyperinflation. Clinical symptoms and signs typically start with an upper respiratory prodrome, including rhinorrhoea, low-grade fever, cough and poor feeding, followed 1 - 2 days later by tachypnoea, hyperinflation and wheeze as a consequence of airway inflammation and air trapping.The illness is generally self limiting, but may become more severe and include signs such as grunting, nasal flaring, subcostal chest wall retractions and hypoxaemia. The most reliable clinical feature of bronchiolitis is hyperinflation of the chest, evident by loss of cardiacdullness on percussion, an upper border of the liver pushed down to below the 6th intercostal space, and the presence of a Hoover sign(subcostal recession, which occurs when a flattened diaphragm pulls laterally against the lower chest wall).Measurement of peripheral arterial oxygen saturation is useful to indicate the need for supplemental oxygen. A saturation of <92% at sea level and 90% inland indicates that the child has to be admitted to hospital for supplemental oxygen. Chest radiographs are generally unhelpful and not required in children with a clear clinical diagnosis of bronchiolitis.Blood tests are not needed routinely. Complete blood count tests have not been shown to be useful in diagnosing bronchiolitis or guiding its therapy. Routine measurement of C-reactive protein does not aid in management and nasopharyngeal aspirates are not usually done.Viral testing adds little to routine management. Risk factors in patients with severe bronchiolitis that require hospitalisation and may even cause death, include prematurity, congenital heart disease and congenital lung malformations.

Acute viral bronchiolitis in South Africa: Strategies for management and prevention

Management of acute viral bronchiolitis is largely supportive. There is currently no proven effective therapy other than oxygen for hypoxic children. The evidence indicates that there is no routine benefit from inhaled, rapid short-acting bronchodilators, adrenaline or ipratropium bromide for children with acute viral bronchiolitis. Likewise, there is no demonstrated benefit from routine use of inhaled or oral corticosteroids, inhaled hypertonic saline nebulisation, montelukast or antibiotics. The last should be reserved for children with severe disease, when bacterial co-infection is suspected. Prevention of respiratory syncytial virus (RSV) disease remains a challenge. A specific RSV monoclonal antibody, palivizumab, administered as an intramuscular injection, is available for children at risk of severe bronchiolitis, including premature infants, young children with chronic lung disease, immunodeficiency, or haemodynamically significant congenital heart disease. Prophylaxis should be commenced at the start of the RSV season and given monthly during the season. The development of an RSV vaccine may offer a more effective alternative to prevent disease, for which the results of clinical trials are awaited. Education of parents or caregivers and healthcare workers about diagnostic and management strategies should include the following: bronchiolitis is caused by a virus; it is seasonal; it may start as an upper respiratory tract infection with low-grade fever; symptoms are cough and wheeze, often with fast breathing; antibiotics are generally not needed; and the condition is usually self limiting, although symptoms may occur for up to four weeks in some children.

Abstract P2-12-09: Developing clinical sequencing assays at Einstein-Montefiore

The Department of Genetics in collaboration with a group of Montefiore's clinicians initiated the development of clinical sequencing tests with the final goal to incrementally build clinical sequencing assays to improve clinical care in the Bronx. The use of next generation sequencing is particularly relevant for cancer biology since the heterogeneity of cancer requires deep sequencing and high read depth, which prior to recent advances in technology was expensive and labor intensive.

We designed a custom gene panel for target sequencing using the Illumina HiSeq 2500 consisting of 650 genes for multiple disorders and diseases, including various cancers, in addition to rare and complex mendelian disorders. We sequenced 17 samples, including a tumor-normal breast cancer pair, where we identified a novel, pathogenic stop variant in the highly mutated TP53 tumor suppressor gene. In addition to our custom target panel, we sequenced this sample pair on two additional cancer panels (AmpliSeq Cancer Hotspot and the Comprehensive Cancer Panel using the Ion Torrent Technology) and performed Whole Exome Sequencing (WES) to ensure the sensitivity and specificity of our custom panel. This variant was detected on all platforms.

We found targeted capture high-throughput sequencing to be a cost effective, time sensitive and efficient approach in detecting pathogenic variants to aid diagnosis of individuals affected by cancer or mendelian disorders. We are currently receiving samples to sequence and plan to expand our program to various groups within the Einstein-Montefiore community. Using a personalized medicine approach we expect to detect biomarkers and prospective targets to develop an accurate and effective treatment plan for these individuals.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P2-12-09.

Is obesity still increasing among pregnant women? Prepregnancy obesity trends in 20 states, 2003-2009

OBJECTIVE

To estimate trends in prepregnancy obesity prevalence among women who delivered live births in the US during 2003-2009, by state, age, and race-ethnicity.

METHODS

We used Pregnancy Risk Assessment Monitoring System (PRAMS) data from 2003, 2006, and 2009 to measure prepregnancy obesity (body mass index [BMI]≥30kg/m(2)) trends in 20 states. Trend analysis included 90,774 records from 20 US states with data for all 3 study years. We used a chi-square test for trend to determine the significance of actual and standardized trends, standardized to the age and race-ethnicity distribution of the 2003 sample.

RESULTS

Prepregnancy obesity prevalence increased by an average of 0.5 percentage points per year, from 17.6% in 2003 to 20.5% in 2009 (P<0.001). Obesity increased among women aged 20-24 (P<0.001), 30-34 (P=0.001) and 35 years or older (P=0.003), and among non-Hispanic white (P<.001), non-Hispanic black (P=0.02), Hispanic (P=0.01), and other women (P=0.03).

CONCLUSION

Overall, prepregnancy obesity prevalence continues to increase and varies by race-ethnicity and maternal age. These findings highlight the need to address obesity as a key component of preconception care, particularly among high-risk groups.

A pilot study of central venous catheter survival in cancer patients using low-molecular-weight heparin (dalteparin) and warfarin without catheter removal for the treatment of upper extremity deep vein thrombosis (The Catheter Study)

BACKGROUND

Central venous catheters in patients with cancer are associated with development of deep vein thrombosis (DVT); however, there is no accepted standard treatment.

OBJECTIVES

To assess the safety and effectiveness of a management strategy for central venous catheter-related DVT in cancer patients consisting of dalteparin and warfarin without the need for line removal.

PATIENTS/METHODS

Patients older than 18 years of age with an active malignancy and who had symptomatic, acute, objectively documented UEDVT were eligible. Patients were treated with dalteparin 200 IU kg(-1) per day for 5-7 days and warfarin with a target International Normalized Ratio of 2.0-3.0. Patients were followed for 3 months for recurrent venous thromboembolism, major hemorrhage and survival of the central venous catheter.

RESULTS

There were 74 patients (48 males). The average age was 58 years. There were no episodes of recurrent venous thromboembolism and three (4%) major bleeds. No lines were removed because of infusion failure or recurrence/extension of DVT.

CONCLUSION

Treatment of UEDVTs secondary to central catheters in cancer patients with standard dalteparin/warfarin can allow the central line to remain in situ with little risk of line failure or recurrence/extension of the DVT.

Pregnancy Intention and Its Relationship to Birth and Maternal Outcomes

OBJECTIVE

To examine whether there are associations between pregnancy intention (intended, unwanted, mistimed, or ambivalent) and negative birth and maternal outcomes: low birth weight (less than 2,500 g), preterm delivery (fewer than 37 weeks), small for gestational age, premature labor, hypertension, and other maternal outcomes.

METHODS

We analyzed data from the population-based Pregnancy Risk Assessment Monitoring System, including 87,087 women who gave birth between 1996 and 1999 in 18 states. Information on pregnancy outcomes was derived from birth certificate data and a self-administered questionnaire completed postpartum. We employed SUDAAN (RTI International, Research Triangle Park, NC) for univariable and logistical regression analyses.

RESULTS

In analyses controlling for demographic and behavioral factors, women with unwanted pregnancies had an increased likelihood of preterm delivery (adjusted odds ratio [OR] 1.16, 95% confidence interval [CI] 1.01-1.33) and premature rupture of membranes (adjusted OR 1.37, 95% CI 1.01-1.85) compared with women with intended pregnancies. Women who were ambivalent toward their pregnancies had increased odds of delivering a low birth weight infant (adjusted OR 1.15, 95% CI 1.02-1.29); in contrast, women with mistimed pregnancies had a lower likelihood (adjusted OR 0.92, 95% CI 0.86-0.97).

CONCLUSION

Pregnancy intention, specifically unwanted and ambivalent, may be an indicator of increased risk for some poor birth and maternal outcomes and should be considered in interventions aimed at improving the health of the mother and child.

LEVEL OF EVIDENCE

III.

Effect of 3.2 vs. 3.8% sodium citrate concentration on anti-Xa levels for patients on therapeutic low molecular weight heparin

In this study, we compared the effect of sodium citrate, a sample collection variable, on the anti-Xa levels of patients (n = 28) on dalteparin, a low molecular weight heparin. The median anti-Xa level for 3.2% sodium citrate was 0.235 U/ml while the median level for 3.8% sodium citrate was 0.230 U/ml. We conclude that different sodium citrate concentrations give statistically equivalent anti-Xa levels for the same samples. This conclusion is in contrast to the findings of the effect of sodium citrate concentration on International Normalized Ratio (INR) and activated partial-thromboplastin time (aPTT). In accordance with previous recommendations, we advocate the exclusive use of 3.2% sodium citrate in an effort to standardize coagulation testing.

Reproductive and contraceptive attitudes as predictors of condom use among women in an HIV prevention intervention

This study prospectively evaluates the effect of childbearing motivation and contraceptive attitudes on consistency of condom use among at-risk women enrolled in an HIV prevention intervention. Women (age 15-40, 85% African-American) were recruited from homeless shelters, drug treatment facilities, and public housing developments and assigned to standard or enhanced intervention conditions. Among the eligible study group of nonsterilized women with a main partner (n = 312), 24.4% wanted to have a baby at baseline; 43.5% believed their partner wanted them to have a baby. Women who reported a desire for a baby, compared to all others, were less likely to be at a higher level of condom consistency six months later (OR = 0.66; .48-.90). Women who perceived partner support for contraceptive use showed a higher level of condom consistency (OR = 1.20; 1.03-1.41) at 6-month follow-up. Many women in this study wanted to have a baby and this desire interfered with subsequent consistency of condom use. We also found that condom use increased toward consistency of use among women whose partner supported contraceptive use. HIV prevention interventions should include screening for reproductive motivation, so that prevention messages can be tailored to the realities of women's lives. Women who want a baby can be educated about disease prevention in the context of pregnancy planning and linked with appropriate services. Women who want to avoid childbearing can be given messages that emphasize the contraceptive benefits of condom use and that help strengthen partner support.

Risks and complications of nonbronchoscopic bronchoalveolar lavage in a pediatric intensive care unit

This paper aims to document the risks and complications of nonbronchoscopic bronchoalveolar lavage (NB-BAL) in 35 mechanically ventilated patients with diffuse severe pneumonia in a single pediatric intensive care unit. A prospective collection of data on patients' ventilatory settings and oxygen requirements before NB-BAL, and oxyhemoglobin saturations and heart rate readings before, during, and after the procedure were taken on each patient. The major complication of NB-BAL was arterial desaturation, which was more severe and prolonged in patients with poor oxygenation indices and PaO(2)/FiO(2) ratios. The diagnostic yield of the procedure was high at 69%.

Self-reported Papanicolaou smears and hysterectomies among women in the United States

OBJECTIVE

To evaluate the potential overuse of Papanicolaou smears among women who have had a hysterectomy.

METHODS

We analyzed two surveys of US women aged 18 years or older, the Behavioral Risk Factor Surveillance System (1992-1997) and the National Health Interview Survey (1993-1994), and one survey of US hospitals (National Hospital Discharge Survey, 1980-1997). We examined the number of women who have had a hysterectomy who had a recent (within 3 years) Papanicolaou smear. We also examined trends in the proportions and rates of hysterectomies by diagnoses and type of procedure that potentially could require a Papanicolaou smear.

RESULTS

From the Behavioral Risk Factor Surveillance System, an estimated 21.2% of US women have had a hysterectomy. Among women who have had a hysterectomy, 78.3% had a recent Papanicolaou smear. Among those reporting no hysterectomy, 82.1% had a recent Papanicolaou smear. Estimates from the National Health Interview Survey were similar. From the National Hospital Discharge Survey, an estimated 6.7% to 15.4% of women with a history of hysterectomy would require a subsequent Papanicolaou smear because they had a diagnosis related to cervical neoplasia or because they had undergone a supracervical hysterectomy. For an estimated 10.6-11.6 million of the 12.5 million women who had a hysterectomy and a recent Papanicolaou smear, that test could be considered unnecessary.

CONCLUSION

Continued Papanicolaou screening of women without an intact uteri may result in excessive use of resources in time and money with minimal impact on decreasing cervical cancer.

Patterns of inpatient surgeries for the top four cancers in the United States, National Hospital Discharge Survey, 1988-95

BACKGROUND

At a time when the population is aging and medical practices are rapidly changing, ongoing surveillance of surgical treatments for cancer is valuable for health services planning.

METHODS

We used data from the National Hospital Discharge Survey for patients with discharge diagnoses of lung, prostate, female breast, and colorectal cancer during 1988-95 to estimate population-based rates and numbers of inpatient surgical procedures.

RESULTS

In 1988-91, rates of lobectomy for lung cancer were significantly higher in males than females. By 1994-95, the male/female differences had largely disappeared due to increasing trends among females and decreasing trends among males. During 1988-95, surgeries on the large intestine for colorectal cancer, including right hemicolectomy and sigmoidectomy, decreased significantly, as did abdominoperineal resections of the rectum. Anterior resections of the rectum increased significantly. Radical prostatectomies for prostate cancer increased from 34,000 in 1988-89 to 104,000 in 1992-93 and then decreased to 87,000 in 1994-95; rates followed a similar pattern. Finally, the number and rates of inpatient mastectomies for female breast cancer decreased over the study period (from 219,000 to 180,000 and from 78.8 to 61.5 per 100,000, respectively).

CONCLUSION

These trends in inpatient surgeries for the major cancers in the US probably reflect changes in disease occurrence and modified treatment recommendations.

Outpatient treatment of pulmonary embolism with dalteparin

BACKGROUND

Pulmonary embolism is a common complication of deep vein thrombosis. It has been established that low molecular weight heparin may be used to treat deep vein thrombosis or pulmonary embolism and randomized studies have established that outpatient management of deep vein thrombosis with low molecular weight heparin is at least as effective as in-hospital management with unfractionated heparin.

METHODS

This was a prospective cohort study of eligible patients with pulmonary embolism managed as outpatients using dalteparin (200 U/kg s/c daily) for a minimum of five days and warfarin for 3 months. Outpatients included those managed exclusively out of hospital and those managed initially for 1-3 days as inpatients who then completed therapy out of hospital. Reasons for admission included hemodynamic instability; hypoxia requiring oxygen therapy; admission for another medical reason; severe pain requiring parenteral analgesia or high risk of major bleeding. Patients were followed for three months for clinically apparent recurrent venous thromboembolism and bleeding.

RESULTS

Between three teaching hospitals, a total of 158 patients with pulmonary embolism were identified. Fifty patients were managed as inpatients and 108 as outpatients. Of the outpatients, 27 were managed for an average of 2.5 days as inpatients and then completed dalteparin therapy as outpatients. The remaining 81 patients were managed exclusively as outpatients with dalteparin. For all outpatients the overall symptomatic recurrence rate of venous thromboembolism was 5.6% (6/108) with only 1.9% (2/108) major bleeds. There were a total of four deaths with none due to pulmonary embolism or major bleed.

CONCLUSIONS

This prospective study suggests that outpatient management of pulmonary embolism is feasible and safe for the majority of patients.

Prevalence of selected maternal and infant characteristics, Pregnancy Risk Assessment Monitoring System (PRAMS), 1997

PROBLEM/CONDITION

Certain maternal behaviors and experiences (e.g., unintended pregnancy, late entry into prenatal care, smoking cigarettes during pregnancy, and physical abuse during pregnancy) might be related to adverse reproductive outcomes (e.g., low birthweight, infant morbidity and mortality, and maternal morbidity). Information on the prevalence of these behaviors and experiences is needed to monitor trends over time, to increase understanding of maternal behaviors and experiences and their relation to perinatal and maternal outcomes, and to develop and assess programs and policies designed to reduce these adverse outcomes among pregnant women and their infants.

REPORTING PERIOD

From 1993 through 1997.

DESCRIPTION OF SYSTEM

The Pregnancy Risk Assessment Monitoring System (PRAMS) is a CDC-developed, ongoing, state- and population-based surveillance system designed to collect information on self-reported maternal behaviors and experiences that occur before, during, and shortly after pregnancy among women who deliver a live-born infant. A 14-page questionnaire is mailed to a sample of mothers that is randomly selected from state birth certificate records. The questionnaire is followed by two additional mailings and follow-up with nonresponders by telephone. Responses are accumulated during the calendar year, combined with birth certificate data, and then weighted to be representative of all mothers who had a live-born infant in the state. Data for 1997 from 13 states were examined.

RESULTS

The prevalence of unintended pregnancy resulting in a live-born infant ranged from 33.9% to 50.0% in the 13 states. From 1993 through 1997, data from Georgia demonstrated a significant decreasing trend (p = .01) in unintended pregnancy, whereas this trend significantly increased in New York (p = .03). In most states, women who were younger (aged <20 years), had less than 12 years of education, were black, and received Medicaid were more likely to report an unintended pregnancy. In 1997, 16.6%-30.7% of women entered prenatal care after the first 3 months of pregnancy. In most states, women who were younger (aged <20 years), black, had lower levels of education, and received Medicaid were more likely to enter prenatal care late or not at all. Georgia and Washington experienced significant decreasing trends in smoking during pregnancy. Across the 13 states, 11.0%-23.9% of women reported smoking during pregnancy. In seven of 13 states, white women were more likely to smoke during pregnancy than black women. In eight of 13 states, smoking was significantly more prevalent among women who delivered a low birthweight infant than women who delivered a normal weight infant. In seven states, the proportion of women who initiated breast-feeding significantly increased from 1993 through 1997; the prevalence in 1997 ranged from 48.1% to 86.8%. Women who were most likely to breast-feed were older, more educated, white, and did not receive Medicaid. The state-specific prevalence of physical abuse during pregnancy by a husband or partner ranged from 2.4% to 5.6%. In most of these states, women who had less than a high school education and women who received Medicaid were more likely to report having been abused.

INTERPRETATION

Findings indicate that many women report high-risk behaviors or experience high-risk conditions before, during, and shortly after pregnancy. Furthermore, several specific groups of women were significantly more likely to report these behaviors or experience these conditions. In many states, women who were younger, less educated, and Medicaid recipients were more likely to experience unintended pregnancy, enter prenatal care after the first 3 months of pregnancy or not at all, smoke during the last 3 months of pregnancy, and never initiate breast-feeding.

PUBLIC HEALTH ACTION

These findings are useful for state agencies to monitor trends in behaviors and experiences and to design public health programs and policies that addre

Outpatient use of low molecular weight heparin (Dalteparin) for the treatment of deep vein thrombosis of the upper extremity

Upper extremity deep vein thrombosis (DVT) is now recognized as a major cause of morbidity and mortality. There is little information regarding the most effective treatment of this condition. We report a prospective cohort study of the use of low molecular weight heparin (LMWH) in the outpatient management of upper extremity DVT. Forty-six patients were managed as outpatients for objectively documented upper extremity DVT with dalteparin (200 aXa u/kg), for a minimum of five days. Warfarin was usually initiated on the first day with a target INR of 2.0-3.0. Most patients had an underlying malignancy or a history of a central line. All patients were followed for 12 weeks from diagnosis. Only one patient had a major bleed. No patients developed pulmonary emboli. One patient had a recurrence of DVT during the treatment with LMWH with extension of the existing thrombus. Seven patients died, all due to their underlying disease. This study supports the safety and effectiveness of dalteparin in the treatment of upper extremity DVT. Given that these patients were treated as outpatients, there is a potential for huge cost savings.

Timing and effectiveness of requirements for a second dose of measles vaccine

OBJECTIVE

Previous measles elimination goals have failed in the United States despite high coverage of schoolchildren with a single dose of measles vaccine. Since 1989 advisory groups have recommended that schoolchildren receive a second dose of measles vaccine as part of a revised strategy to eliminate measles from the US. States have responded by phasing in requirements for a second dose of measles vaccine at school entry for various age groups at primary school entrance, secondary school entrance or both. The purpose of this analysis was to evaluate the effectiveness of the requirements for a second dose of measles vaccine and to determine whether a primary or secondary school entrance requirement was more effective in lowering measles incidence.

METHODS

Using national surveillance data we examined the influence of state requirements for the second dose of measles vaccine on measles incidence from 1993 through 1995.

RESULTS

Overall measles incidence was lower in states that had a requirement for a second dose of measles vaccine at either primary school entrance [relative risk (RR) = 0.35; 95% confidence interval, 0.25 to 0.49] or secondary school entrance (RR = 0.38; 95% confidence interval 0.29 to 0.50), compared with states without a second dose requirement. Incidence was lowest in states that required a second dose of measles vaccine at both primary and secondary school entrance (RR = 0.22; 95% confidence interval, 0.13 to 0.37).

CONCLUSIONS

Our findings demonstrate that a requirement for a second dose of measles vaccine at either primary or secondary school entrance is effective in lowering measles incidence, with a greater reduction occurring in states where the second dose is required for both age groups.

Isolation and characterization of a human gene containing a nuclear localization signal from the critical region for velo-cardio-facial syndrome on 22q11

Velo-cardio-facial syndrome (VCFS) and DiGeorge syndrome are congenital disorders characterized by craniofacial anomalies, conotruncal heart defects, immune deficiencies, and learning disabilities. Both diseases are associated with similar hemizygous 22q11 deletions, indicating that haploinsufficiency of a gene(s) in 22q11 is responsible for their etiology. We describe here a new gene called NLVCF, which maps to the critical region for VCFS on 22q11 between the genes HIRA and UFD1L. NLVCF encodes a putative protein of 206 amino acids. The coding region encompasses four exons that span a genomic interval of 3.4 kb. Coding sequence analysis revealed that NLVCF is a novel gene that contains two consensus sequences for nuclear localization signals. The Nlvcf mouse homolog is 75% identical in amino acid sequence and maps to the orthologous region on mouse chromosome 16. The human NLVCF transcript is 1.3 kb in size and is expressed at varying levels in many fetal and adult tissues. Whole-mount in situ hybridization showed that Nlvcf is expressed in most structures of 9.5-dpc mouse embryos, with especially high expression in the head as well as in the first and second pharyngeal arches. NLVCF and HIRA are divergently transcribed, and their start codons lie approximately 1 kb apart in both humans and mice. Interestingly, the two genes exhibit a similar expression pattern in mouse embryos, suggesting that they may share common regulatory elements. The pattern of expression of NLVCF and its localization in the critical region suggest that NLVCF may contribute to the etiology of VCFS.

Expanding eligibility for outpatient treatment of deep venous thrombosis and pulmonary embolism with low-molecular-weight heparin: a comparison of patient self-injection with homecare injection

BACKGROUND

The outpatient treatment of patients with deep vein thrombosis and pulmonary embolism using low-molecular-weight heparin has the potential to reduce health care costs, but it is unclear if most patients with deep vein thrombosis and pulmonary embolism can be treated as outpatients. In the published studies, more than 50% of patients were excluded from outpatient treatment for reasons such as comorbid conditions, short life expectancy, concomitant pulmonary embolism, and previous deep vein thrombosis, and many patients were not treated entirely at home. We sought to determine if expanding patient eligibility for the outpatient treatment of deep vein thrombosis and pulmonary embolism affects the safety and effectiveness of the treatment, and to determine if patient self-injection compared with injections administered by a homecare nurse affected these outcomes.

PATIENTS AND METHODS

We treated as outpatients all patients with deep vein thrombosis and pulmonary embolism, except for those with massive pulmonary embolism, high risk for major bleeding or an active bleed, phlegmasia, and patients hospitalized for reasons that prevented discharge. We compared 2 models of outpatient care to determine feasibility, safety, and efficacy. Both models involved nurse managers who provided daily patient contact and ongoing treatment; however, in one model the patients were taught to inject themselves and in the other model homecare nurses administered the injections. We expanded the population of patients eligible for outpatient treatment by including many patients not treated at home in previous studies. Most patients in our study were treated with dalteparin sodium, 200 U/kg every 24 hours, for a minimum of 5 days. Therapy with warfarin sodium was started on the day of diagnosis or the following day. Patients were followed up for 3 months to determine rates of recurrent venous thromboembolism, bleeding, and death.

RESULTS

In this study, 194 (83%) of 233 consecutive patients were deemed eligible and treated as outpatients. Of the 39 patients who did not receive home therapy, 20 had concomitant medical problems responsible for their admission or were already inpatients, 6 had massive pulmonary embolism, 6 refused to pay for the dalteparin therapy, 4 had active bleeding, and 3 had phlegmasia cerulea dolens, which required treatment with intravenous narcotics for pain control. More than 184 (95%) of the 194 patients were treated entirely at home. There was no significant difference (P>.99) in the rate of recurrent venous thromboembolic events between the patients who were injected by homecare nurses (3/95 [3.2%]) and those who injected themselves (4/99 [4.0%]). Combining the 2 models, the overall recurrent event rate was 3.6% (95% confidence interval, 1.5%-7.4%). Similarly, there were no significant differences in rates of major hemorrhage (2/95 vs 2/99; P>.99), minor hemorrhage (8/95 vs 2/99; P = .06), and death (6/95 vs 8/99; P = .63). The overall rate of major hemorrhage was 2.0% (95% confidence interval, 0.6%-5.2%).

CONCLUSIONS

We demonstrate that more than 80% of patients at our tertiary care hospital could be treated at home using 1 of the 2 models of care we describe. Our results demonstrate that patients can safely and effectively perform home self-injection under the supervision of a hospital-based nurse. Injections at home by a homecare nurse are similarly effective. Our overall rates of recurrent venous thromboembolism, bleeding, and death are at least as favorable as those previously reported despite using 1 dose per day of dalteparin for most patients.

Randomized assessment of a warfarin nomogram for initial oral anticoagulation after venous thromboembolic disease

Standard treatment for venous thromboembolism is parenteral heparin followed by warfarin. In this study we assess whether a standardized method of ordering warfarin reduces the duration of hospitalization. Consecutive patients were randomized to receive warfarin managed by attending physicians or by a nomogram. Patients were stratified according to primary or secondary venous thromboembolism. Prothrombin times were measured daily and heparin was given for a minimum of 5 days and stopped when the International Normalized Ratio was >1.9. Patients were followed for 3 months. There were 111 patients, 80 with primary and 31 with secondary venous thromboembolism. Overall there were no differences between the two warfarin groups with respect to length of admission. Given the prolonged duration of admission in many patients with secondary venous thromboembolism, a subset analysis was conducted on the 80 patients with primary venous thromboembolism. Patients in the standard group stayed significantly longer than patients in the nomogram group (6.0 vs. 5.6 days, p = 0.02). The warfarin nomogram as tested is safe and leads to a significantly shorter length of stay for patients with primary venous thromboembolism as compared to standard practice.

Incontinentia pigmenti in a newborn male infant with DNA confirmation

We report on a woman with incontinentia pigmenti (IP), who had two successive term pregnancies. The first pregnancy ended in the birth of a male infant, who is alive and well at 2 years. A second liveborn male had early postnatal distress and died after 1 day of life, after a fulminating clinical course. Polymorphic microsatellite markers, closely linked to the IP gene on the X chromosome, showed that each son inherited a different X chromosome from his mother. Although in most instances IP appears to be prenatally lethal for the male, the phenotype is not completely known. We propose that the neonatal phenotype may be characterized by lethal disturbances in the hematopoietic and immunologic systems.

Comparative mapping of the human 22q11 chromosomal region and the orthologous region in mice reveals complex changes in gene organization

The region of human chromosome 22q11 is prone to rearrangements. The resulting chromosomal abnormalities are involved in Velo-cardio-facial and DiGeorge syndromes (VCFS and DGS) (deletions), "cat eye" syndrome (duplications), and certain types of tumors (translocations). As a prelude to the development of mouse models for VCFS/DGS by generating targeted deletions in the mouse genome, we examined the organization of genes from human chromosome 22q11 in the mouse. Using genetic linkage analysis and detailed physical mapping, we show that genes from a relatively small region of human 22q11 are distributed on three mouse chromosomes (MMU6, MMU10, and MMU16). Furthermore, although the region corresponding to about 2.5 megabases of the VCFS/DGS critical region is located on mouse chromosome 16, the relative organization of the region is quite different from that in humans. Our results show that the instability of the 22q11 region is not restricted to humans but may have been present throughout evolution. The results also underscore the importance of detailed comparative mapping of genes in mice and humans as a prerequisite for the development of mouse models of human diseases involving chromosomal rearrangements.

Hysterectomy surveillance--United States, 1980-1993

PROBLEM/CONDITION

In the United States, approximately 600,000 hysterectomies are performed each year, and the procedure is the second most frequently performed major surgical procedure among reproductive-aged women.

REPORTING PERIOD COVERED

1980-1993.

DESCRIPTION OF SYSTEM

This surveillance system uses data obtained from CDC's National Hospital Discharge Survey (NHDS) to describe the epidemiology of hysterectomy. The NHDS is an annual probability sample of discharges from non-Federal, short-stay hospitals in the United States.

RESULTS

In the United States during 1980-1993, an estimated 8.6 million women aged > or =15 years had a hysterectomy. The overall rate of hysterectomy declined slightly from 1980 (7.1 hysterectomies per 1,000 women) to 1987 (6.6 per 1,000 women). The redesign of the NHDS in 1988 resulted in a decrease in estimated rates (i.e., the average annual rate for 1988-1993 was 5.5 per 1,000 women). Rates differed by age, with women aged 40-44 years most likely to have this procedure. Overall annual rates of hysterectomy did not differ significantly by race. The diagnosis most often associated with hysterectomy was uterine leiomyoma; during 1988-1993, this diagnosis accounted for 62% of hysterectomies among black women, 29% among white women, and 45% among women of other races. During 1988-1993, the percentage of hysterectomies performed by the vaginal route increased significantly; furthermore, an increasingly higher percentage of vaginal hysterectomies were accompanied by bilateral oophorectomy. From 1991 through 1993, laparoscopy was associated more frequently with vaginal hysterectomy than in previous years.

INTERPRETATION

The rate of hysterectomy decreased slightly during the first half of the 14-year surveillance period, then leveled off during the second half. The increase in simultaneous coding of laparoscopy and vaginal hysterectomy on hospital discharge forms probably reflected the growing use of laparoscopically assisted vaginal hysterectomy.

ACTIONS TAKEN

Continued surveillance for hysterectomy will enable changes in clinical practice (e.g., the use of LAVH) to be identified, and information derived from the surveillance system may assist in directing biomedical assessment priorities (e.g., to determine the reasons for race-specific differences in the prevalence of uterine leiomyoma).

Identification, characterization, and precise mapping of a human gene encoding a novel membrane-spanning protein from the 22q11 region deleted in velo-cardio-facial syndrome

Velo-cardio-facial syndrome (VCFS) and DiGeorge syndrome (DGS) are characterized by a wide spectrum of phenotypes including cleft palate, conotruncal heart defects, and facial dysmorphology. Hemizygosity for a portion of chromosome 22q11 has been detected in 80-85% of VCFS/DGS patients. Using a cDNA selection protocol, we have identified a new gene, TMVCF (transmembrane protein deleted in VCFS), which maps to the deleted interval. The genomic locus is positioned between polymorphic markers D22S944 and D22S941. TMVCF encodes a small protein of 219 amino acids that is predicted to contain two membrane-spanning domains. TMVCF is expressed abundantly in human adult lung, heart, and skeletal muscle, and transcripts can be detected at least as early as Day 9 of mouse development.

Detection of an atypical 22q11 deletion that has no overlap with the DiGeorge syndrome critical region

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Molecular analysis of velo-cardio-facial syndrome patients with psychiatric disorders

Velo-cardio-facial syndrome (VCFS) is characterized by conotruncal cardiac defects, cleft palate, learning disabilities, and characteristic facial appearance and is associated with hemizygous deletions within 22q11. A newly recognized clinical feature is the presence of psychiatric illness in children and adults with VCFS. To ascertain the relationship between psychiatric illness, VCFS, and chromosome 22 deletions, we evaluated 26 VCFS patients by clinical and molecular biological methods. The VCFS children and adolescents were found to share a set of psychiatric disorders, including bipolar spectrum disorders and attention-deficit disorder with hyperactivity. The adult patients, >18 years of age, were affected with bipolar spectrum disorders. Four of six adult patients had psychotic symptoms manifested as paranoid and grandiose delusions. Loss-of-heterozygosity analysis of all 26 patients revealed that all but 3 had a large 3-Mb common deletion. One patient had a nested distal deletion and two did not have a detectable deletion. Somatic cell hybrids were developed from the two patients who did not have a detectable deletion within 22q11 and were analyzed with a large number of sequence tagged sites. A deletion was not detected among the two patients at a resolution of 21 kb. There was no correlation between the phenotype and the presence of the deletion within 22q11. The remarkably high prevalence of bipolar spectrum disorders, in association with the congenital anomalies of VCFS and its occurrence among nondeleted VCFS patients, suggest a common genetic etiology.

Identification of a new human catenin gene family member (ARVCF) from the region deleted in velo-cardio-facial syndrome

Velo-cardio-facial syndrome (VCFS) and DiGeorge syndrome (DGS) are characterized by a wide spectrum of phenotypes, including conotruncal heart defects, cleft palate, and facial dysmorphology. Hemizygosity for a portion of chromosome 22q11 has been detected in 80-85% of VCFS/DGS patients. Both syndromes are thought to be the result of a developmental field defect. Using two independent gene-isolation procedures, we isolated a new catenin family member termed ARVCF (armadillo repeat gene deleted in VCFS) from the interval deleted in VCFS. ARVCF encodes a protein of 962 amino acids that contains a coiled coil domain and 10 tandem armadillo repeats. The primary structure of the protein is most closely related to the murine catenin p120CAS, which suggests a role for ARVCF in protein-protein interactions at adherens junctions. ARVCF is expressed ubiquitously in all fetal and adult tissues examined. This gene is hemizygous in all VCFS patients with interstitial deletions. Based on the physical location and potential functions of ARVCF, we suggest that hemizygosity at this locus may play a role in the etiology of some of the phenotypes associated with VCFS.

Bipolar spectrum disorders in patients diagnosed with velo-cardio-facial syndrome: does a hemizygous deletion of chromosome 22q11 result in bipolar affective disorder?

OBJECTIVE

The purpose of this study was to conduct a systematic assessment of psychiatric illness in patients diagnosed with velo-cardio-facial syndrome, a genetic syndrome that involves over 40 somatic anomalies, learning disabilities, and behavioral disorders and is associated with a microdeletion on chromosome 22q11.

METHOD

Subjects were referred for psychiatric diagnostic evaluation without regard to age or previous psychiatric history. In order to establish DSM-III-R consensus clinical diagnoses for patients who ranged in age from 5 to 34 years, the Diagnostic Interview for Children and Adolescents--Revised or the Structured Clinical Interview for DSM-III-R (SCID) was used. A review of available medical and psychiatric records and a clinical interview performed by two research psychiatrists to validate specific symptoms and syndromes reported in the Diagnostic Interview for Children and Adolescents--Revised and the SCID were used to elucidate the chronological appearance and duration of symptoms.

RESULTS

Sixty-four percent (N = 16 of 25) of this unselected series of patients with velo-cardio-facial syndrome met DSM-III-R criteria for a spectrum of bipolar disorders with full syndromal onset in late childhood or early adolescence (mean age at onset = 12 years, SD = 3). In addition, 20% (N = 5) met DSM-III-R criteria for attention deficit hyperactivity disorder (ADHD), while 16% (N = 4) met criteria for attention deficit disorder without hyperactivity. In contrast to previous reports of a high prevalence of schizophrenia, none of the patients was diagnosed with schizophrenia, and only four had psychotic symptoms during a phase of their illness, all in their 20s or 30s.

CONCLUSIONS

Given that the prevalence of bipolar disorder in the general population is estimated to be 1.5% and that the average age at onset is 24, these findings support an unusually strong association between velo-cardio-facial syndrome and early-onset bipolar disorder and suggest that a gene deleted at the 22q11 chromosomal locus may be involved in its pathogenesis. If confirmed, these findings may provide a new and fruitful line of investigation into the molecular basis of bipolar spectrum disorders.

Association of codon 108/158 catechol-O-methyltransferase gene polymorphism with the psychiatric manifestations of velo-cardio-facial syndrome

Velo-cardio-facial-syndrome (VCFS) is a common congenital disorder associated with typical facial appearance, cleft palate, cardiac defects, and learning disabilities. The majority of patients have an interstitial deletion on chromosome 22q11. In addition to physical abnormalities, a variety of psychiatric illnesses have been reported in patients with VCFS, including schizophrenia, bipolar disorder, and attention deficit hyperactivity disorder. The psychiatric manifestations of VCFS could be due to haploin-sufficiency of a gene(s) within 22q11. One candidate that has been mapped to this region is catechol-O-methyltransferase (COMT). We recently identified a polymorphism in the COMT gene that leads to a valine-->methionine substitution at amino acid 158 of the membrane-bound form of the enzyme. Homozygosity for COMT158met leads to a 3-4-fold reduction in enzymatic activity, compared with homozygotes for COMT158val. We now report that in a population of patients with VCFS, there is an apparent association between the low-activity allele, COMT158met, and the development of bipolar spectrum disorder, and in particular, a rapid-cycling form.

Meiotic pachytene arrest in MLH1-deficient mice

Germ line mutations in DNA mismatch repair genes including MLH1 cause hereditary nonpolyposis colon cancer. To understand the role of MLH1 in normal growth and development, we generated mice that have a null mutation of this gene. Mice homozygous for this mutation show a replication error phenotype, and extracts of these cells are deficient in mismatch repair activity. Homozygous mutant males show normal mating behavior but have no detectable mature sperm. Examination of meiosis in these males reveals that the cells enter meiotic prophase and arrest at pachytene. Homozygous mutant females have normal estrous cycles and reproductive and mating behavior but are infertile. The phenotypes of the mlh1 mutant mice are distinct from those deficient in msh2 and pms2. The different phenotypes of the three types of mutant mice suggest that these three genes may have independent functions in mammalian meiosis.

Isolation of a new clathrin heavy chain gene with muscle-specific expression from the region commonly deleted in velo-cardio-facial syndrome

Velo-cardio-facial syndrome (VCFS) and DiGeorge syndrome (DGS) are developmental disorders characterized by a spectrum of phenotypes including velopharyngeal insufficiency, conotruncal heart defects and facial dysmorphology among others. Eighty to eighty-five percent of VCFS/DGS patients are hemizygous for a portion of chromosome 22. It is likely that the genes encoded by this region play a role in the etiology of the phenotypes associated with the disorders. Using a cDNA selection protocol, we isolated a novel clathrin heavy chain cDNA (CLTD) from the VCFS/DGS minimally deleted interval. The cDNA encodes a protein of 1638 amino acids. CLTD shares significant homology, but is not identical to the ubiquitously expressed clathrin heavy chain gene. The CLTD gene also shows a unique pattern of expression, having its maximal level of expression in skeletal muscle. Velopharyngeal insufficiency and muscle weakness are common features of VCFS patients. Based on the location and expression pattern of CLTD, we suggest hemizygosity at this locus may play a role in the etiology of one of the VCFS-associated phenotypes.

Schizophrenia susceptibility associated with interstitial deletions of chromosome 22q11

We report the results of two studies examining the genetic overlap between schizophrenia and velocardiofacial syndrome. In study A, we characterize two interstitial deletions identified on chromosome 22q11 in a sample of schizophrenic patients. The size of the deletions was estimated to be between 1.5 and 2 megabases. In study B, we examine whether variations in deletion size are associated with the schizophrenic phenotype in velocardiofacial syndrome patients. Our results show that a region of the genome that has been previously implicated by genetic linkage analysis can harbor genetic lesions that increase the susceptibility to schizophrenia. Our findings should facilitate identification and cloning of the schizophrenia susceptibility gene(s) in this region and identification of more homogeneous subgroups of patients.

Lingual haematoma after treatment with alteplase (recombinant tissue plasminogen activator) for acute myocardial infarction

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Velo-cardio-facial syndrome: frequency and extent of 22q11 deletions

Velo-cardio-facial (VCFS) or Shprintzen syndrome is associated with deletions in a region of chromosome 22q11.2 also deleted in DiGeorge anomaly and some forms of congenital heart disease. Due to the variability of phenotype, the evaluation of the incidence of deletions has been hampered by uncertainty of diagnosis. In this study, 54 patients were diagnosed with VCFS by a single group of clinicians using homogeneous clinical criteria independent of the deletion status. Cell lines of these patients were established and the deletion status evaluated for three loci within the commonly deleted region at 22q11.2 using fluorescence in situ hybridization (FISH). In 81% of the patients all three loci were hemizygous. In one patient we observed a smaller interstitial deletion than that defined by the three loci. The phenotype of this patient was not different from that observed in patients with larger deletions.

Molecular definition of the 22q11 deletions in velo-cardio-facial syndrome

Velo-cardio-facial syndrome (VCFS) is a common genetic disorder among individuals with cleft palate and is associated with hemizygous deletions in human chromosome 22q11. Toward the molecular definition of the deletions, we constructed a physical map of 22q11 in the form of overlapping YACs. The physical map covers > 9 cM of genetic distance, estimated to span 5 Mb of DNA, and contains a total of 64 markers. Eleven highly polymorphic short tandem-repeat polymorphic (STRP) markers were placed on the physical map, and 10 of these were unambiguously ordered. The 11 polymorphic markers were used to type the DNA from a total of 61 VCFS patients and 49 unaffected relatives. Comparison of levels of heterozygosity of these markers in VCFS patients and their unaffected relatives revealed that four of these markers are commonly hemizygous among VCFS patients. To confirm these results and to define further the breakpoints in VCFS patients, 15 VCFS individuals and their unaffected parents were genotyped for the 11 STRP markers. Haplotypes generated from this study revealed that 82% of the patients have deletions that can be defined by the STRP markers. The results revealed that all patients who have a deletion share a common proximal breakpoint, while there are two distinct distal breakpoints. Markers D22S941 and D22S944 appear to be consistently hemizygous in patients with deletions. Both of these markers are located on a single nonchimeric YAC that is 400 kb long. The results also show that the parental origin of the deleted chromosome does not have any effect on the phenotypic manifestation.

The frequency of integrative transformation at phase-specific genes of Candida albicans correlates with their transcriptional state

The phase transition between the white and opaque phenotypes in the switching system of Candida albicans strain WO-1 is accompanied by the differential expression of the white-specific gene WH11 and the opaque-specific gene PEP1. The frequency of integrative transformation at the white-specific gene locus WH11 is between 4.5 and 7.0 times more frequent in white than in opaque spheroplasts, and the frequency of disruptive transformation at the opaque-specific gene locus PEP1 is 30.5 times more frequent in opaque spheroplasts than in white spheroplasts. In contrast, the frequencies of integrative transformation at the constitutively expressed loci ADE2 and EF1 alpha 2 are similar in the white and opaque phases. Therefore, the frequency of integration of linear plasmid DNA containing sequences of phase-specific genes correlates with the transcriptional state of the targeted locus.

Partial nucleotide sequence of a single ribosomal RNA coding region and secondary structure of the large subunit 25 s rRNA of Candida albicans

A rDNA cistron of Candida albicans strain WO-1 was cloned and the ITS1, ITS2, 5.8 s rDNA and 25 s rDNA coding regions sequenced in their entirety. These sequences were compared to those of three related yeast species (Saccharomyces cerevisiae, Saccharomyces carlsbergensis, and Thermomyces lanuginosus), and the 5.8 s rDNA was compared to seven additional 5.8 s rDNAs from organisms ranging in complexity from D. discoideum to H. sapiens. The C. albicans ITS regions are shorter than those of most other eukaryotes. The 25 s and 5.8 s rDNA sequences were folded into a secondary structure model based on comparative methods. In a comparison of regional similarities between the large subunit rDNAs of C. albicans, the three related yeasts and other eukaryotes, it is demonstrated that the additional sequences not present in the E. coli 23 s rDNA are more variable than the regions present in both prokaryotes and eukaryotes.

Developmental and molecular biology of switching in Candida albicans

Candida albicans and related species switch frequently and reversibly between a number of general phenotypes usually discriminated by colony morphology and in some cases by cellular morphology. Switching has been demonstrated to affect a number of physiologic and architectural characteristics of single cells including most of the putative virulence factors of C.albicans. In the past few years, we have cloned several genes regulated by switching in the white-opaque transition of C.albicans strain WO-1. Two of the genes, PEP1 and Op4, are transcribed only in the opaque phase, and one of the genes, Wh11, is transcribed only in the white phase. These coordinately regulated genes are unlinked in the genome and do not undergo sequence reorganization in switching. With the identification of a cis-acting regulatory sequence in the five-prime flanking sequence of Wh11, we now believe that phase-specific genes are regulated by transacting factors and that these factors may be coded for or under the direct regulation of a single master regulatory gene at which site the basic switch event occurs.