Outbreak of Legionnaires' disease on a cruise ship: lessons for international surveillance and control

A sporadic case of Legionnaires' disease was linked to travel on a cruise ship. Investigation identified two further cases of Legionnaires' Disease and one case of non-pneumonic Legionella infection. An Incident Team confirmed the source to be the ship's water system and control measures were instituted that included pasteurisation, super chlorination and chlorine dioxide dosing. The Public Health Laboratory Service (PHLS) Communicable Disease Surveillance Centre (CDSC), through the European Surveillance Scheme for Travel Associated Legionnaires' Disease, identified three previous cases associated with the same ship's water system including one fatality. Lessons for the international surveillance and control of Legionnaires' disease on cruise ships are discussed.

Guidelines for investigating single cases of Legionnaires' disease

These guidelines for the investigation of single cases of legionnaires' disease have been updated from those produced in 1994 to take account of developments in microbiological and environmental diagnostic capabilities and the recognition that infection may be acquired from the patient's domestic water system. The new guidelines recommend that when a case of legionnaires' disease has been diagnosed, it should be investigated to determine whether it is part of an outbreak or cluster, work related, suspected to be a hospital acquired infection or is travel associated. If information concerning the patient's movements during the incubation period shows it to be none of these, then appropriate environmental investigations should be considered which might include the patient's domestic water system as a potential source of infection. The guidelines are designed to provide advice and information to all public health personnel involved in the control and prevention of legionnaires' disease.

The hcKrox gene family regulates multiple extracellular matrix genes

The transcription factor cKrox was originally identified as a protein that bound to a negative transcription regulatory element in the murine alpha1(I) collagen promoter. We recently reported the cloning and characterization of human cKrox (hcKrox). Overexpression of hcKrox in NIH3T3 fibroblasts efficiently repressed the promoters of the fibronectin and alpha1(I) collagen genes (70-90%) in transient transfection assays and suppressed the endogenous genes in hcKrox expressing permanent cell lines. We have now isolated genomic clones and cDNAs encoding two novel transcription factors related to hcKrox termed hcKrox-beta and hcKrox-gamma (the original clone is now referred to as hcKrox-alpha). Both contain three kruppel-like zinc-finger DNA binding motifs that are 71-78% identical to those of hcKrox-alpha. The NH(2)-terminus of all three proteins contains a POZ domain, a conserved 120 amino acid motif involved in transcriptional repression and protein dimerization. RT-PCR experiments demonstrate that all three hcKrox family members are expressed in foreskin and dermal fibroblasts. Transient transfection studies in NIH3T3 fibroblasts demonstrate that hcKrox-alpha -beta and -gamma, as well as the murine cKrox-beta homologue, LRF, suppress transcription driven by promoters for the alpha1(I) and alpha2(I) collagen, fibronectin and elastin genes. Electrophoretic mobility shift assays and coimmunoprecipitation studies suggest that homo- and heterodimerization occurs between cKrox family members. Dimer formation is influenced by amino acids in the NH(2)-terminal POZ domain and the Zn(+2)-finger region. Immunoprecipitation studies indicate that cKrox can form heterodimers in solution in the absence of DNA. Thus, a multi-gene family exists that can coordinately regulate several extracellular matrix genes and has the potential to form many heterodimeric transcription factors.

Ca2+-independent binding of an EF-hand domain to a novel motif in the alpha-actinin-titin complex

The interaction between alpha-actinin and titin, two modular muscle proteins, is essential for sarcomere assembly. We have solved the solution structure of a complex between the calcium-insensitive C-terminal EF-hand domain of alpha-actinin-2 and the seventh Z-repeat of titin. The structure of the complex is in a semi-open conformation and closely resembles that of myosin light chains in their complexes with heavy chain IQ motifs. However, no IQ motif is present in the Z-repeat, suggesting that the semi-open conformation is a general structural solution for calcium-independent recognition of EF-hand domains.

A structural characterization of the interactions between titin Z-repeats and the alpha-actinin C-terminal domain

Titin and alpha-actinin, two modular muscle proteins, are with actin the major components of the Z-band in vertebrate striated muscles where they serve to organize the antiparallel actin filament arrays in adjacent sarcomeres and to transmit tension between sarcomeres during activation. Interactions between titin and alpha-actinin have been mainly localized in a 45-amino acid multiple motif (Z-repeat) in the N-terminal region of titin and the C-terminal region of alpha-actinin. In this study, we provide the first quantitative characterization of alpha-actinin-Z-repeat recognition and dissect the interaction to its minimal units. Different complementary techniques, such as circular dichroism, calorimetry, and nuclear magnetic spectroscopy, were used. Two overlapping alpha-actinin constructs (Act-EF34 and Act-EF1234) containing two and four EF-hand motifs, respectively, were produced, and their folding properties were examined. Complex formation of Act-EF34 and Act-EF1234 with single- and double-Z-repeat constructs was studied. Act-EF34 was shown quantitatively to be necessary and sufficient for binding to Z-repeats, excluding the presence of additional high-affinity binding sites in the remaining part of the domain. The binding affinities of the different Z-repeats for Act-EF34 range from micromolar to millimolar values. The strongest of these interactions are comparable to those observed in troponin C-troponin I complexes. The binding affinities for Act-EF34 are maximal for Zr1 and Zr7, the two highly homologous sequences present in all muscle isoforms. No cooperative or additional contributions to the interaction were observed for Z-repeat double constructs. These findings have direct relevance for evaluating current models of Z-disk assembly.

Lessons learned from the National Medicare & You Education Program

In fall 1998 CMS implemented the National Medicare Education Program (NMEP) to educate beneficiaries about their Medicare program benefits; health plan choices; supplemental health insurance; beneficiary rights, responsibilities, and protections; and health behaviors. CMS has been monitoring the implementation of the NMEP in six case study sites as well as monitoring each of the information channels for communicating with beneficiaries. This article describes select findings from the case studies, and highlights from assessment activities related to the Medicare & You handbook, the toll-free 1-800-MEDICARE Helpline, Internet, and Regional Education About Choices in Health (REACH).

A longitudinal study of drinking and cognitive performance in elderly Japanese American men: the Honolulu-Asia Aging Study

OBJECTIVES

This study prospectively describes the relationships between alcohol intake and subsequent cognitive performance among participants in the Honolulu Heart Program (HHP).

METHODS

Alcohol intake was assessed at Exam III of the HHP, and cognitive performance was measured approximately 18 years later with the Cognitive Abilities Screening Instrument (CASI). Complete information was available for 3556 participants, aged 71 to 93 years at follow-up.

RESULTS

In multivariate analyses, the relationship between drinking and later cognitive performance appeared nonlinear, as nondrinkers and heavy drinkers (more than 60 ounces of alcohol per month) had the lowest CASI scores and the highest risks of poor and intermediate CASI outcomes. Compared with nondrinkers, the risk of a poor CASI score was lowered by 22% to 40% among men who consumed 1-60 ounces of alcohol per month.

CONCLUSIONS

We report a positive association between moderate alcohol intake among middle-aged men and subsequent cognitive performance in later life. However, it is possible that the health risks associated with drinking outweight any potential benefits for many elderly persons.

Binding of alpha-actinin to titin: implications for Z-disk assembly

Titin is an exceptionally large protein (M.Wt. approximately 3 MDa) that spans half the sarcomere in muscle, from the Z-disk to the M-line. In the Z-disk, it interacts with alpha-actinin homodimers that are a principal component of the Z-filaments linking actin filaments. The interaction between titin and alpha-actinin involves repeating approximately 45 amino acid sequences (Z-repeats) near the N-terminus of titin and the C-lobe of the C-terminal calmodulin-like domain of alpha-actinin. The conformation of Z-repeat 7 (ZR7) of titin when complexed with the 73-amino acid C-terminal portion of alpha-actinin (EF34) was studied by heteronuclear NMR spectroscopy using (15)N-labeling of ZR7 and found to be helical over a stretch of 18 residues. Complex formation resulted in the protection of one site of preferential cleavage of EF34 at Phe14-Leu17, as determined by limited proteolysis experiments coupled to mass spectrometry measurements. Intermolecular NOEs show Val16 of ZR7 to be positioned close in space to the backbone of EF34 around Phe14. These observations suggest that the mode of binding of ZR7 to EF34 is similar to that of troponin I to troponin C and of peptide C20W to calmodulin. These complexes would appear to represent a general alternative binding mode of calmodulin-like domains to target peptides.

Travel associated legionnaires’disease in Europe: 1997 and 1998

The European Surveillance Scheme for Travel Associated Legionnaires’ Disease was set up by the European Working Group on Legionella Infections (EWGLI) in 1987 to identify cases of legionella infection in returning travellers and to detect outbreaks and cl

Multiple folding pathways for heterologously expressed human prion protein

Human PrP (residues 91-231) expressed in Escherichia coli can adopt several conformations in solution depending on pH, redox conditions and denaturant concentration. Oxidised PrP at neutral pH, with the disulphide bond intact, is a soluble monomer which contains 47% alpha-helix and corresponds to PrPC. Denaturation studies show that this structure has a relatively small, solvent-excluded core and unfolds to an unstructured state in a single, co-operative transition with a DeltaG for folding of -5.6 kcal mol-1. The unfolding behaviour is sensitive to pH and at 4.0 or below the molecule unfolds via a stable folding intermediate. This equilibrium intermediate has a reduced helical content and aggregates over several hours. When the disulphide bond is reduced the protein adopts different conformations depending upon pH. At neutral pH or above, the reduced protein has an alpha-helical fold, which is identical to that observed for the oxidised protein. At pH 4 or below, the conformation rearranges to a fold that contains a high proportion of beta-sheet structure. In the reduced state the alpha- and beta-forms are slowly inter-convertible whereas when oxidised the protein can only adopt an alpha-conformation in free solution. The data we present here shows that the human prion protein can exist in multiple conformations some of which are known to be capable of forming fibrils. The precise conformation that human PrP adopts and the pathways for unfolding are dependent upon solvent conditions. The conditions we examined are within the range that a protein may encounter in sub-cellular compartments and may have implications for the mechanism of conversion of PrPC to PrPSc in vivo. Since the conversion of PrPC to PrPSc is accompanied by a switch in secondary structure from alpha to beta, this system provides a useful model for studying major structural rearrangements in the prion protein.

Lower thrombolytic use for African Americans with myocardial infarction: an influence of clinical presentation?

BACKGROUND

After myocardial infarction, African Americans have been reported to undergo fewer catheterization and revascularization procedures than whites, but few studies have addressed racial variations in the delivery of thrombolytic therapy.

METHODS

We conducted a retrospective analysis of data prospectively collected on consecutive patients admitted with acute myocardial infarction to the 16-bed coronary care unit of a large, urban teaching hospital.

RESULTS

Over a 5-year period, 1948 consecutive patients were admitted with acute myocardial infarction to a single coronary care unit. Thrombolysis was administered to 19% of 1024 African Americans and 29% of 924 whites (P <.01). The initial diagnostic impression on admission was "definite" infarction less often in African Americans (30%) than in whites (43%, P <.001), a difference that appeared to largely account for the difference in thrombolytic administration in a multivariable model. Mortality adjusted for age and concomitant illnesses was similar in African Americans compared with whites (relative risk 1.0, 95% confidence interval 0.78 to 1.51).

CONCLUSIONS

Much of the racial variation in thrombolytic administration could be accounted for by differences in clinical presentation, an issue that requires further study.

Primary pulmonary melanoma: case report and literature review

Primary pulmonary melanoma is a very rare disease, with only 19 cases previously reported in the English language literature. These cases suggest that melanoma can arise in the lung as a primary tumor, probably from residual melanoblasts. Primary pulmonary melanoma is frequently endobronchial and often manifests with symptoms of cough, hemoptysis, and lobar collapse. Aggressive surgical resection, irrespective of lymph node involvement, offers possible long-term survival in some patients. The diagnosis of primary pulmonary melanoma necessitates that both clinical and histologic criteria be fulfilled. Herein diagnostic criteria are proposed, and the diagnostic approach is discussed.

Successful techniques for retention of study participants in an inner-city population

The purpose of this work was to describe methods of retaining participants in studies of inner-city populations, including the timing and intensity of contacts; and to describe the characteristics of participants who did not complete all follow-up interviews and/or return all peak flow diaries in the National Cooperative Inner-City Asthma Study. A cohort study design was used involving hospital emergency rooms and community clinics in seven major urban areas. Participants included 1337 4- to 9-year-old asthmatic children and their caretakers. Nearly 89% of participants completed 3-, 6-, and 9-month follow-up interviews. The 15% of participants who completed a baseline interview on the weekends were significantly more likely to complete follow-up interviews on a weekend. The percent of follow-up interviews conducted in person increased over time from 5% to 8%. The percent of participants with complete follow-up increased as the number of contact names increased (86% with zero contacts, 91% with two contracts; p = 0.03, test for trend). Participants who required at least four phone calls to complete the 3- and 6-month assessment were significantly more likely to be black, have higher participant stress, and have a smoker in the household (p < 0.05). Multiple logistic regression suggests that higher social support and lower parental stress were both predictors of completed interviews. Within our study sample of inner-city minority participants with asthmatic children, only a small proportion of participants missed any follow-up interviews. Increased caretaker stress, decreased social support, and inability to provide several alternate contacts were all predictive of retention problems. Having a flexible staff, computer tracking, and face-to-face recruitment appear essential to achieving nearly complete follow-up within a population historically difficult to follow.

Incremental beamwise backprojection using geometrical symmetries for 3D PET reconstruction in a cylindrical scanner geometry

Cho et al have proposed a fast backprojection scheme for parallel beam geometries, the incremental algorithm, which performs backprojection on a ray-by-ray (beam-by-beam) basis as opposed to a pixel-by-pixel approach. We present an extension of this incremental, beamwise, backprojection algorithm to the case of volume reconstruction of data acquired by a cylindrical, multiring positron tomograph. Use is made of geometrical symmetries of the image volume. This method results in a twelve-fold reduction of execution time compared with a straightforward, voxel-driven implementation of the same interpolation equations.

European surveillance of travel associated legionnaires' disease 1996

The European Surveillance Scheme for Travel Associated Legionnaires' Disease was established in 1987 to identify clusters and outbreaks of cases of the disease. Twenty-nine collaborating centres in 25 countries contribute case reports in a standard format

Mapping and use of a sequence that targets DNA ligase I to sites of DNA replication in vivo

The mammalian nucleus is highly organized, and nuclear processes such as DNA replication occur in discrete nuclear foci, a phenomenon often termed "functional organization" of the nucleus. We describe the identification and characterization of a bipartite targeting sequence (amino acids 1-28 and 111-179) that is necessary and sufficient to direct DNA ligase I to nuclear replication foci during S phase. This targeting sequence is located within the regulatory, NH2-terminal domain of the protein and is dispensable for enzyme activity in vitro but is required in vivo. The targeting domain functions position independently at either the NH2 or the COOH termini of heterologous proteins. We used the targeting sequence of DNA ligase I to visualize replication foci in vivo. Chimeric proteins with DNA ligase I and the green fluorescent protein localized at replication foci in living mammalian cells and thus show that these subnuclear functional domains, previously observed in fixed cells, exist in vivo. The characteristic redistribution of these chimeric proteins makes them unique markers for cell cycle studies to directly monitor entry into S phase in living cells.

Design and methods of the National Cooperative Inner-City Asthma Study

The National Cooperative Inner-City Asthma Study (NCICAS) was established to identify and then intervene on those factors which are related to asthma morbidity among children in the inner-city. This paper describes the design and methods of the broad-based initial Phase I epidemiologic investigation. Eight research centers enrolled 1,528 children, 4 to 9 years of age, from English- or Spanish-speaking families, all of whom resided in major metropolitan inner-city areas. The protocol included an eligibility assessment and an extensive baseline visit, during which symptom data, such as wheezing, lost sleep, changes in activities of daily living, inpatient admissions, and emergency department and clinic visits were collected. A comprehensive medical history for each child was taken and adherence to the medical regimen was assessed. Access, as well as barriers, to the medical system were addressed by a series of questions including the location, availability, and consistency of treatment for asthma attacks, follow-up care, and primary care. The psychological health of the caretaker and of the child was also measured. Asthma knowledge of the child and caretaker was determined. Sensitization to allergens was assessed by skin-prick allergen testing and exposure to cigarette smoke and the home environment were assessed by questionnaire. For more than a third of the families, in-home visits were conducted with dust sample allergen collection and documentation of the home environment, such as the presence of pets and evidence of smoking, mildew, and roaches. Urine specimens were collected to measure passive smoke exposure by cotinine assays, blood samples were drawn for banking, and children age 6 to 9 years were given spirometric lung function assessment. At 3, 6 and 9 months following the baseline assessment, telephone interviews were conducted to ask about the child's symptoms, unscheduled emergency department or clinic visits, and hospitalizations. At this time, peak flow measurements with 2-week diary symptom records were collected.

Effect of a monitored care unit on resource utilization in a pediatric ICU

OBJECTIVE: To determine the effect of a monitored care unit on resource utilization in a pediatric ICU. METHODS: The study was done at a 205-bed pediatric medical center located in northern California. Efficiency of resource utilization in the pediatric ICU was evaluated by comparing the following factors before and after the implementation of a monitored care unit: (1) efficiency in the pediatric ICU, (2) number of patients turned away for lack of beds, (3) hours of nursing care per patient day, and (4) cost (as estimated from charge ratios) in the monitored care unit for care of patients admitted because of some common reasons. RESULTS: Efficiency in the pediatric ICU increased significantly after implementation of a monitored care unit. The number of patients not admitted to the pediatric ICU because not enough beds were available was identical before and after establishment of the monitored care unit. After the monitored care unit was established, hours of nursing care per patient day were significantly reduced, enabling the number of patient days to be increased without increasing cost. In addition, cost comparisons showed a decrease in both length of stay and total cost per admission for patients undergoing ventriculoperitoneal shunt revision and lambdoidal suture synostectomy. CONCLUSIONS: Use of beds in the pediatric ICU was more efficient when a high-observation setting was available for low-risk monitored patients. Key differences in patterns of use were observed. Compared with the pediatric ICU, the monitored care unit requires fewer personnel and less expensive equipment and supplies, but it still allows potentially life-threatening complications to be recognized and treated. For patients who meet its admission criteria, the monitored care unit is a safe alternative to the pediatric ICU.

Effect of a monitored care unit on resource utilization in a pediatric ICU

OBJECTIVE

To determine the effect of a monitored care unit on resource utilization in a pediatric ICU.

METHODS

The study was done at a 205-bed pediatric medical center located in northern California. Efficiency of resource utilization in the pediatric ICU was evaluated by comparing the following factors before and after the implementation of a monitored care unit: (1) efficiency in the pediatric ICU, (2) number of patients turned away for lack of beds, (3) hours of nursing care per patient day, and (4) cost (as estimated from charge ratios) in the monitored care unit for care of patients admitted because of some common reasons.

RESULTS

Efficiency in the pediatric ICU increased significantly after implementation of a monitored care unit. The number of patients not admitted to the pediatric ICU because not enough beds were available was identical before and after establishment of the monitored care unit. After the monitored care unit was established, hours of nursing care per patient day were significantly reduced, enabling the number of patient days to be increased without increasing cost. In addition, cost comparisons showed a decrease in both length of stay and total cost per admission for patients undergoing ventriculoperitoneal shunt revision and lambdoidal suture synostectomy.

CONCLUSIONS

Use of beds in the pediatric ICU was more efficient when a high-observation setting was available for low-risk monitored patients. Key differences in patterns of use were observed. Compared with the pediatric ICU, the monitored care unit requires fewer personnel and less expensive equipment and supplies, but it still allows potentially life-threatening complications to be recognized and treated. For patients who meet its admission criteria, the monitored care unit is a safe alternative to the pediatric ICU.