0935 Association Between Chronotype, Sleep Duration, Weekend Catch-Up Sleep, and Depression Among Korean High School Students

Introduction

The present study aimed to examine the association between chronotype, sleep duration, weekend catch-up sleep (CUS) duration, and depression among Korean high school students.

Methods

A total of 8,565 high school students who were analyzed from 15 nationwide districts in South Korea completed an online self-report questionnaire. Depressive mood was assessed using the Korean version of the Beck Depression Inventory. The following sleep characteristics were assessed: weekday and weekend sleep durations, weekend CUS duration, chronotype, perceived sufficiency of sleep, self-reported snoring and sleep apnea, daytime sleepiness, and sleep environment. Age, sex, body mass index, number of private classes, and proneness to internet addiction were also measured. Logistic regression analysis was conducted to compute odds ratios for the association between depression and sleep characteristics, after controlling for relevant covariates.

Results

The prevalence of depression (BDI ≥ 16) was 1,794 (20.9%). In the analyses of multivariate logistic regression, the late chronotype (odds ratio [OR], 1.71; 95% CI, 1.47-1.99), female (OR, 2.24; 95% CI, 1.99-2.53), underweight (OR, 1.27; 95% CI, 1.02-1.57) and obesity (OR, 1.41; 95% CI, 1.13-1.75), weekday sleep duration (OR, 0.86; 95% CI, 0.81-0.91), weekend CUS duration ≥ 2 hours (OR, 0.68; 95% CI, 0.55-0.85), ESS (OR, 1.08; 95% CI, 1.07-1.10), much (OR, 2.15; 95% CI, 1.63-2.84) and insufficient (OR, 1.71; 95% CI, 1.46-2.01) perceived sleep, snoring (OR, 1.27; 95% CI, 1.11-1.46) and witnessed apnea (OR, 2.10; 95% CI, 1.75-2.52), increased internet addiction (OR, 1.06; 95% CI, 1.05-1.06), high number of private education (OR, 0.76; 95% CI, 0.60-0.95), and poor sleep environment (OR, 1.86; 95% CI, 1.56-2.21) were associated with depression.

Conclusion

Eveningness preference, insufficient weekday sleep duration, short weekend CUS duration, and self-reported snoring and sleep apnea were associated with an increased risk for depression.

Support

 

Informatics and public health at CDC

Since CDC acquired its first mainframe computer in 1964, the use of information technology in public health practice has grown steadily and, during the past 2 decades, dramatically. Public health informatics (PHI) arrived on the scene during the 1990s after medical informatics (intersecting information technology, medicine, and health care) and bioinformatics (intersecting mathematics, statistics, computer science, and molecular biology). Similarly, PHI merged the disciplines of information science and computer science to public health practice, research, and learning. Using strategies and standards, practitioners employ PHI tools and training to maximize health impacts at local, state, and national levels. They develop and deploy information technology solutions that provide accurate, timely, and secure information to guide public health action.

Public health 101 for informaticians

Abstract Public health is a complex discipline that has contributed substantially to improving the health of the population. Public health action involves a variety of interventions and methods, many of which are now taken for granted by the general public. The specific focus and nature of public health interventions continue to evolve, but the fundamental principles of public health remain stable. These principles include a focus on the health of the population rather than of individuals; an emphasis on disease prevention rather than treatment; a goal of intervention at all vulnerable points in the causal pathway of disease, injury, or disability; and operation in a governmental rather than a private context. Public health practice occurs at local, state, and federal levels and involves various professional disciplines. Public health principles and practice are illustrated by a case study example of neural tube defects and folic acid. The application of information science and technology in public health practice provides previously unfathomed opportunities to improve the health of the population. Clinical informaticians and others in the health care system are crucial partners in addressing the challenges and opportunities offered by public health informatics.

Long-term local control and survival after concomitant boost accelerated radiotherapy for locally advanced cervix cancer

Between 1989 and 1994, a prospective clinical trial tested the safety and efficacy of concomitant boost accelerated superfractionated (CBASF) radiotherapy for patients with locally advanced cervix cancer. CBASF radiotherapy included 45 Gy/25 fractions to the pelvis and a 14.4 Gy/9 fraction concomitant boost to the primary tumor, followed by brachytherapy for a total point A dose of 85 Gy to 90 Gy. The 22 patients of International Federation of Gynecology and Obstetrics stages IIIA-IVA who received CBASF radiotherapy now have a median follow-up time of more than 8 years. The 7-year actuarial rates of local control and overall survival are 81% and 36%, respectively. Serious late toxicity included bowel injury requiring colostomy in eight patients within 2.5 years after treatment, but no other severe toxicity was observed after longer follow-up intervals. The local control and survival rates achieved with CBASF radiotherapy were higher than those observed within a matched contemporaneous cohort of patients treated with standard radiotherapy alone at the same institution (p = 0.1 for local control, 0.09 for survival). The encouraging trend toward improved tumor control, tempered by the complication rate, suggests an opportunity to apply more sophisticated radiotherapy techniques that might sustain the favorable effects of dose intensification while mitigating the normal tissue toxicity.

Bioterrorism preparedness: planning for the future

The release of nerve gas in a Tokyo subway and attempted releases of biological agents by the Aum Shinrikyo cult have demonstrated the willingness and ability of modern-day terrorists to use unconventional weapons. Unlike explosive weapons, the use of biologic weapons may only become apparent once people become ill. The detection and response to these man-made outbreaks will occur initially at the medical and public health levels. Therefore, the Centers for Disease Control and Prevention and its partners are strengthening their response, disease detection, diagnostic, and communication capabilities to better protect the nation's citizens against biological or chemical terrorism.

Mandatory reporting of diseases and conditions by health care professionals and laboratories

CONTEXT

Surveillance is a key component of the core public health function of health assessment. Systematic reporting by health care professionals and laboratories, which may vary by state law, statute, or regulation, continues to provide essential data for assessing public health.

OBJECTIVE

To describe the state and territorial reporting requirements for diseases and conditions recommended for national public health surveillance.

DESIGN, SETTING, AND PARTICIPANTS

Between May and August 1997, the state and territorial epidemiologists from all 50 states, in addition to New York City, Puerto Rico, and Guam, completed questionnaires indicating which diseases and conditions were reportable by health care professionals and laboratories in their jurisdictions. The surveys were subsequently updated to reflect reporting requirements current as of January 1, 1999. The overall response rate for the survey was 100% for US states and 90% overall, including the territories.

MAIN OUTCOME MEASURE

State and territorial reporting requirements for diseases and conditions of public health concern.

RESULTS

Of the 58 diseases and conditions recommended for national reporting, 35 (60%) were reportable in greater than 90% of the states and territories, 15 (26%) were reportable in 75% to 90%, and 8 (14%) were reportable in less than 75%. Nineteen of the infectious diseases were reportable in all of the states and territories that responded.

CONCLUSIONS

Required reporting varies substantially by state or territory. Health care professionals are integral to public health efforts at the local, state, and national levels.

Differences in notifiable infectious disease morbidity among adult women--United States, 1992-1994

By 1990, all 50 states were using the Centers for Disease Control and Prevention (CDC) National Electronic Telecommunications System for Surveillance to report individual case data that included demographic information (without personal identifiers) about most notifiable diseases. This analysis of National Notifiable Diseases Surveillance System (NNDSS) data is useful for evaluating the distribution of reported notifiable infectious diseases among adult women by age and race. The number of cases of the 48 nationally notifiable infectious diseases reported among adult women (i.e., women > or = 15 years of age) were compiled for 1992-1994. These data were then analyzed by age and race, and rates per 100,000 adult women were calculated. During 1992-1994, the 10 most commonly reported nationally notifiable diseases among adult women in the United States were, in descending order of frequency, gonorrhea, primary/secondary syphilis, acquired immunodeficiency syndrome (AIDS), salmonellosis, tuberculosis, hepatitis A, hepatitis B, shigellosis, Lyme disease, and hepatitis C/non-A non-B. Gonorrhea was the most commonly reported notifiable infectious disease for women of all ages, except those ages > or = 55 years, and for women of all races, except Asian/Pacific Islanders. Tuberculosis was the most commonly reported infectious disease among women of Asian/Pacific Island descent. Analysis of NNDSS data provides information about the relative reported burden of diseases among women of all ages and different races. This information may be used for targeting research, prevention, and control efforts.

History and current status of the National Notifiable Diseases Surveillance System

The National Notifiable Diseases Surveillance System (NNDSS) has origins dating more than a century ago and continues to serve today as a timely source of national data. Both the history and the current status of the NNDSS illustrate the collaborative effort required among persons at all levels of the medical and public health systems. The evolution of the list of conditions considered nationally notifiable demonstrates the responsiveness of the system to changing priorities. The NNDSS has also evolved with the development of technology; it currently uses computers for the collection of data rather than letters or telegrams. These fundamental factors--partnerships, shifting priorities, and rapidly changing technology--will continue to characterize and to influence the practice of public health surveillance as it evolves during the 21st century.

Fatiguing illness among employees in three large state office buildings, California, 1993: was there an outbreak?

The objective was to determine if a cluster of chronic fatigue syndrome (CFS)-like illness had occurred among employees in two large state office buildings in northern California, and to identify risk factors for and features of fatiguing illness in this population.

DESIGN

case-control study.

POPULATION AND SETTING

Over 3300 current employees in two state office buildings and employees in a comparable "control" building. Information was collected on demographic and occupational variables, the occurrence of fatiguing illness for at least one month in the previous year, and the presence of 36 symptoms. A total of 3312 (82%) of 4035 employees returned questionnaires. Overall, 618 (18.7%) persons reported fatigue lasting at least one month; including 382 (11.5%) with fatigue of at least six months' duration and 75 (2.3%) with symptoms compatible with a CFS-like illness. Independent risk factors for fatigue lasting one month or longer were found to be Native American ethnicity (OR 2.4, CI 1.1,5.3), Hispanic ethnicity (OR 1.7, CI 1.3,2.3), female sex (OR 1.5, CI 1.2,1.9), gross household incomes of less than $50,000 (OR 1.3, CI 1.1,1.6), and less than a college education (OR 1.3, CI 1.1,1.6). Similar risks were observed for persons who reported fatigue lasting six months or longer. Female sex (OR 3.2, CI 1.7, 6.4) was the only independent risk factor found for those persons classified as having a CFS-like illness. Case prevalence rates for all three categories of fatigue, as determined by multivariate analysis, were not significantly different among buildings. Despite finding a substantial number of employees with fatiguing illness in the two state office buildings, the prevalence was not significantly different than that for a comparable control building. Previously unidentified risk factors for fatigue of at least one month and at least six months identified in this population included Hispanic ethnicity, not having completed college, and income below $50,000.

Two human cDNAs, including a homolog of Arabidopsis FUS6 (COP11), suppress G-protein- and mitogen-activated protein kinase-mediated signal transduction in yeast and mammalian cells

We have isolated two novel human cDNAs, gps1-1 and gps2, that suppress lethal G-protein subunit-activating mutations in the pheromone response pathway of the yeast Saccharomyces cerevisiae. Suppression of other pathway-activating events was examined. In wild-type cells, expression of either gps1-1 or gps2 led to enhanced recovery from cell cycle arrest induced by pheromone. Sequence analysis indicated that gps1-1 contains only the carboxy-terminal half of the gps1 coding sequence. The predicted gene product of gps1 has striking similarity to the protein encoded by the Arabidopsis FUS6 (COP11) gene, a negative regulator of light-mediated signal transduction that is known to be essential for normal development. A chimeric construct containing gps1 and FUS6 sequences also suppressed the yeast pheromone pathway, indicating functional conservation between these human and plant genes. In addition, when overexpressed in mammalian cells, gps1 or gps2 potently suppressed a RAS- and mitogen-activated protein kinase-mediated signal and interfered with JNK activity, suggesting that signal repression is part of their normal function. For gps1, these results are consistent with the proposed function of FUS6 (COP11) as a signal transduction repressor in plants.

Recurrent outbreaks of Salmonella Enteritidis infections in a Texas restaurant: phage type 4 arrives in the United States

In recent years infection caused by Salmonella serotype Enteritidis (SE) phage type 4 has spread through Europe but has been uncommon in the USA. The first recognized outbreak of this strain in the USA occurred in a Chinese restaurant in EI Paso, Texas, in April 1993; no source was identified. In September 1993, a second outbreak caused by SE phage type 4 was associated with the same restaurant. To determine the cause of the second outbreak, we compared food exposures of the 19 patients with that of two control groups. Egg rolls were the only item significantly associated with illness in both analyses (first control group: odds ratio [OR] 8.2, 95% confidence interval [CI] 2.3-31.6; second control group: OR 13.1, 95% CI 2.1-97.0). Retrospective analysis of the April outbreak also implicated egg rolls (OR 32.4, 95% CI 9.1-126.6). Egg roll batter was made from pooled shell eggs and was left at room temperature throughout the day. These two outbreaks of SE phage type 4 likely could have been prevented by using pasteurized eggs and safe food preparation practices.

Epidemic cholera in Latin America, 1991-1993: implications of case definitions used for public health surveillance

This report presents the various cholera case definitions used by the affected countries of Latin America, shows the numbers of cholera cases and deaths attributable to cholera (as reported by Latin American countries to PAHO through 1993), and describes some regional trends in cholera incidence. The information about how cholera cases were defined was obtained from an October 1993 PAHO questionnaire. In all, 948429 cholera cases were reported to PAHO by affected Latin American countries from January 1991 through December 1993, the highest annual incidences being registered in Peru (1991 and 1992) and Guatemala (1993). The case-fatality rate over the three-year period, and also in 1993, was 0.8%. A general downward trend in the incidence of cholera was observed in most South American countries, while the incidence increased in most Central American countries. A good deal of variation was noted in the definitions used for reporting cholera cases, hospitalized cholera cases, and cholera-attributable deaths. Because of these variations, broad intercountry comparisons (including disease burden calculations and care quality assessments based on case-fatality rates) are difficult to make, and even reported trends within a single country need to be evaluated with care. The situation is likely to be complicated in the future by the arrival of V. cholerae O139 in Latin America, creating a need to distinguish between it and the prevailing O1 strain. For purposes of simplicity, wide acceptance, and broad dissemination of case data, the following definitions are recommended: Confirmed case of O1 cholera: laboratory-confirmed infection with toxigenic V. cholerae O1 in any person who has diarrhea. Confirmed case of O139 cholera: laboratory-confirmed infection with toxigenic V. cholerae O139 in any person who has diarrhea. Clinical case of cholera: acute watery diarrhea in a person over 5 years old who is seeking treatment. Death attributable to cholera: death within one week of the onset of diarrhea in a person with confirmed or clinically defined cholera. Hospitalized patient with cholera:a person who has confirmed or clinically defined cholera and who remains at least 12 hours in a health care facility for treatment of the disease.

Epidemic cholera in Guatemala, 1993: transmission of a newly introduced epidemic strain by street vendors

Epidemic cholera reached Guatemala in July 1991. By mid-1993, Guatemala ranked third in the hemisphere in reported cases of cholera. We conducted a case-control study with two age-, sex-, and neighbourhood-matched controls per patient in periurban Guatemala City. Twenty-six patients hospitalized for cholera and 52 controls were enrolled. Seven (47%) of 15 stool cultures obtained after admission yielded toxigenic Vibrio cholerae O1. All seven were resistant to furazolidone, sulfisoxazole, and streptomycin, and differed substantially by pulsed-field gel electrophoresis from the Latin American epidemic strain dominant in the hemisphere since 1991. In univariate analysis, illness was associated with consumption of left-over rice (odds ratio [OR] = 7.0, 95% confidence interval [CI] = 1.4-36), flavored ices (-helados') (OR = 3.6, CI = 1.1 - 12), and street-vended non-carbonated beverages (OR = 3.8, CI = 1.2-12) and food items (OR = 11.0, CI = 2.3-54). Street-vended food items remained significantly associated with illness in multivariate analysis (OR = 6.5, CI = 1.4-31). Illness was not associated with drinking municipal tap water. Maintaining water safety is important, but slowing the epidemic in Guatemala City and elsewhere may also require improvement in street vendor food handling and hygiene.

Epidemiology of diarrheal disease outbreaks on cruise ships, 1986 through 1993

OBJECTIVE

To describe the epidemiology of cruise-associated diarrheal disease outbreaks from 1986 through 1993, to determine if the incidence had changed since 1985, and to determine the preventability of outbreaks that continue to occur.

DESIGN

The numerator data were collated from Centers for Disease Control and Prevention (CDC) outbreak investigation reports from 1986 through 1993. The denominator data were summations of cruise ship data on the number of passengers and length of cruises collected during routine diarrheal illness surveillance, available only for the period 1989 through 1993.

SETTINGS

Cruise ships with outbreaks of diarrheal disease.

PARTICIPANTS

Cruise ship passengers and crew of staff ho participated in the original investigations.

MAIN OUTCOME MEASURES

The incidence of outbreaks during the study period, pathogens isolated, and vehicles of transmission implicated in investigations.

RESULTS

Among cruises of 3 to 15 days, CDC staff investigated 1.4 outbreaks per 1000 cruises, or 2.3 outbreaks per 10 million passenger-days. An etiologic agent was implicated in 21 (68%) of 31 investigated outbreaks: bacterial in 12, viral in nine. A specific vehicle of transmission was identified in 16. The most common vehicles of transmission were undercooked scallops (three outbreaks caused by enterotoxigenic Escherichia coli), eggs (two outbreaks caused by Salmonella serotype Enteritidis, one by Norwalk-like virus), and food items provided by caterers during onshore excursions (three outbreaks, one caused by Shigella sonnei).

CONCLUSIONS

Observance of two simple precautions could have prevented almost one third (5/16, or 31%) of the investigated outbreaks on cruise ships. Cruise lines have been reminded to cook seafoods thoroughly and to use pasteurized eggs for menu items calling for pooled eggs. Preventing food handlers from working while ill and not using onshore caterers for offship excursions might have prevented at least an additional one third (5/16) of these outbreaks.

An outbreak of cholera from food served on an international aircraft

In February 1992, an outbreak of cholera occurred among persons who had flown on a commercial airline flight from South America to Los Angeles. This study was conducted to determine the magnitude and the cause of the outbreak. Passengers were interviewed and laboratory specimens were collected to determine the magnitude of the outbreak. A case-control study was performed to determine the vehicle of infection. Seventy-five of the 336 passengers in the United States had cholera; 10 were hospitalized and one died. Cold seafood salad, served between Lima, Peru and Los Angeles, California was the vehicle of infection (odds ratio, 11.6; 95% confidence interval, 3.3-44.5). This was the largest airline-associated outbreak of cholera ever reported and demonstrates the potential for airline-associated spread of cholera from epidemic areas to other parts of the world. Physicians should obtain a travel history and consider cholera in patients with diarrhoea who have travelled from cholera-affected countries. This outbreak also highlights the risks associated with eating cold foods prepared in cholera-affected countries.

A cluster of Escherichia coli O157:H7 infections with the hemolytic-uremic syndrome and death in California. A mandate for improved surveillance

In mid-January 1993, an outbreak of Escherichia coli O157:H7 infections associated with eating hamburger patties at a fast-food restaurant chain (chain A) was reported in Washington State. From mid-December to mid-January, 9 cases of E coli O157:H7-associated bloody diarrhea and the hemolytic-uremic syndrome had been reported in San Diego County, California. A total of 34 persons had bloody diarrhea, the hemolytic-uremic syndrome, or E coli O157:H7 organisms isolated from stool during the period November 15, 1992, through January 31, 1993. Organisms of E coli O157:H7 identified from 6 persons were indistinguishable from those of the Washington outbreak strain. Illness was associated with eating at chain A restaurants in San Diego (odds ratio, 13; 95% confidence interval, 1.7, 99) and with eating regular-sized hamburgers (odds ratio, undefined; lower-limit 95% confidence interval, 1.3). Improved surveillance by mandating laboratory- and physician-based reporting of cases of E coli O157:H7 infection and the hemolytic-uremic syndrome might have alerted health officials to this outbreak sooner, which could have resulted in earlier investigation and the institution of measures to prevent more cases.

Drug-resistant Mycobacterium tuberculosis in California, 1991 to 1992

To determine the proportion and distribution of drug-resistant Mycobacterium tuberculosis in California, we surveyed all California counties for drug-susceptibility test results for initial isolates from tuberculosis cases counted during the first quarters of 1991 and 1992. Overall, drug-susceptibility test results were not available for 17% of isolates. Among isolates with available test results, the proportion with resistance to isoniazid averaged 8.7%, and the proportion with resistance to at least 2 drugs, multidrug resistance, averaged 5.9% during these two quarters. The proportion of isolates with drug resistance did not change substantially during these time periods. The proportion with combined isoniazid and rifampin resistance remained stable at about 1.1%. Among persons whose isolates were tested for drug resistance, those with a known previous diagnosis of tuberculosis (relative risk [RR] = 2.6; 95% confidence interval [CI], 1.6 to 4.3; P < .01) and persons who were foreign born (RR = 1.7; 95% CI, 1.1 to 2.7; P = .014) were more likely to have isoniazid-resistant organisms. These statewide data suggest that the initial tuberculosis treatment regimen in California should include 4 antituberculosis drugs, as recommended by the American Thoracic Society and the Centers for Disease Control and Prevention for areas with a prevalence of isoniazid resistance of 4% or greater. The lack of test results for 1 in 6 patients with tuberculosis suggests the need for improved physician and laboratorian education to implement the recommendations that drug susceptibility be tested on all initial isolates.

Truncated forms of a novel yeast protein suppress the lethality of a G protein alpha subunit deficiency by interacting with the beta subunit

In Saccharomyces cerevisiae, the mating pheromone-initiated signal is transduced by a heterotrimeric G protein and normally results in transient cell cycle arrest and differentiation. A null allele of the G alpha (GPA1/SCG1) subunit results in cell death due to unchecked signaling from the G beta gamma (STE4, STE18, respectively) heterodimer. We have identified three high copy suppressors of gpa1 lethality. Two of these genes encode known transcription factors. Mat alpha 2p and Mcm1p. The third is a truncated form of a novel gene, SYG1. Overexpressed wild type SYG1 is a weak suppressor of gpa1. In contrast, the isolated mutant allele SYG1-1 is a strong suppressor that completely blocks the cell cycle arrest and differentiation phenotypes of gpa1 cells of both mating types. One deletion mutant (SYG1 delta 340) can suppress the cell cycle arrest associated with gpa1, but the cells retain a differentiated morphology. SYG1-1 can suppress the effects of overexpressed wild type G beta but is not able to suppress the lethality of an activated G beta mutant (STE4Hpl). Consistent with these genetic observations, the suppressing form of Syg1p can interact with the STE4 gene product, as determined by a two-hybrid assay. SYG1-1 is also capable of promoting pheromone recovery in wild type cells, as judged by halo assay. The sequence of SYG1 predicts eight membrane-spanning domains. Deletion mutants of SYG1 indicate that complete gpa1 suppression requires removal of all of these hydrophobic regions. Interestingly, this truncated protein localizes to the same plasma membrane-enriched subcellular fraction as does full-length Syg1p. Three hypothetical yeast proteins, identified by their similarity to the SYG1 primary sequence within the gpa1 suppression domain, also appear to have related structures. The properties of Syg1p are consistent with those of a transmembrane signaling component that can respond to, or transduce signals through, G beta or G beta gamma.

Irritant dermatitis among workers cleaning up a pesticide spill: California 1991

An outbreak of dermatitis occurred among county jail inmates who removed dead fish from the Sacramento River in California after a spill of metam sodium. The spilled chemical decomposes to methylisothiocyanate (MITC), a known skin irritant. A retrospective cohort study was conducted among the inmates and their crew leaders. Among 42 jail group members, 27 had dermatitis involving the feet and ankles; dermatitis was associated with lower extremity water contact (RR = 3.4, 95% CI 1.0-11.8); the attack rate increased with length of time spent in the water. For comparison, other state and federal employees who worked in the river at the same time were also interviewed. None reported dermatitis. Over three-quarters (24/31) of these other clean-up workers whose feet became wet changed to dry clothing immediately; none of the jail group changed immediately. The river concentration of MITC measured 20-40 ppb at the time of exposure. We speculate that prolonged wetness, occlusive boots, friction, and heat contributed to chemical irritation at this low concentration; the experience of the other clean-up workers suggests that this outbreak could have been prevented.

Assembly of the Photosystem II oxygen-evolving complex is inhibited in psbA site-directed mutants of Chlamydomonas reinhardtii. Aspartate 170 of the D1 polypeptide

Photosystem II catalyzes the photooxidation of water to molecular oxygen, providing electrons to the photosynthetic electron transfer chain. The D1 and D2 chloroplast-encoded reaction center polypeptides bind cofactors essential for Photosystem II function. Transformation of the chloroplast genome of the eukaryotic green alga Chlamydomonas reinhardtii has allowed us to engineer site-directed mutants in which aspartate residue 170 of D1 is replaced by histidine (D170H), asparagine (D170N), threonine (D170T), or proline (D170P). Mutants D170T and D170P are completely deficient in oxygen evolution, but retain normal (D170T) or 50% (D170P) levels of Photosystem II reaction centers. D170H and D170N accumulate wild-type levels of PSII centers, yet evolve oxygen at rates approximately 45% and 15% those of control cells, respectively. Kinetic analysis of chlorophyll fluorescence in the mutants reveals a specific defect in electron donation to the reaction center. Measurements of oxygen flash yields in D170H show, however, that those reaction centers capable of evolving oxygen function normally. We conclude that aspartate residue 170 of the D1 polypeptide plays a critical role in the initial binding of manganese as the functional chloroplast oxygen-evolving complex is assembled.

Epidemic keratoconjunctivitis in a university medical center ophthalmology clinic; need for re-evaluation of the design and disinfection of instruments

During the period from early December 1987 to late January 1988, an outbreak of epidemic keratoconjunctivitis (EKC) caused by adenovirus type 8 occurred at a university medical center eye clinic. A telephone survey of patients revealed an attack rate of 17% among patients seen during the epidemic period. A case-control study demonstrated that development of EKC was associated with exposure to pneumotonometry and to three caregivers. After controlling for exposure to pneumotonometry, however, only exposure to one caregiver was significantly associated with risk of the disease. On January 19, 1988, after recognition of the outbreak, the eye clinic instituted additional infection control measures. A survey of patients seen the following week showed a substantial decrease in the attack rate (1.9%). Before these control measures were implemented, clinic personnel had followed the manufacturer's recommendations and disinfected pneumotonometer tips with 70% isopropyl alcohol, fearing that other disinfectants would corrode the instrument metal. Isopropyl alcohol, shown to have limited activity against adenovirus in vitro, also was being used to "disinfect" pneumotonometer tips between uses at six other area eye clinics polled by telephone. The results of this study demonstrate the need for changes in the design and manufacture of equipment used in the eye clinic.

Chronic fatigue syndrome. A critical appraisal of the role of Epstein-Barr virus

The symptom complex currently designated the chronic fatigue syndrome was previously termed the chronic or chronic active Epstein-Barr virus syndrome or the chronic mononucleosis syndrome, prematurely assuming an etiologic role for the Epstein-Barr virus (EBV). This presumption derived from the fact that some patients with the chronic fatigue syndrome have very high or very low titers of certain antibodies to EBV. A review of seroepidemiologic patterns of response to EBV and of studies of patients with the chronic fatigue syndrome shows that these antibody titers overlap considerably both with those of controls or other healthy persons and with those of patients with other illnesses. Given the high prevalence of exposure to EBV, it would be difficult to determine whether the virus caused the syndrome or whether the antibody elevations resulted from the illness, even if distinct differences in titers existed. Other methodologic issues of control selection, laboratory test comparability, and differing case definitions pose problems in studying this syndrome. The recently published working case definition should facilitate the continuing search for causes.