Engineering mammalian cells for solid-state sensor applications

A fundamental advance in the development and application of cell- and tissue-based biosensors would be the ability to achieve air-dry stabilization of mammalian (especially human) cells with subsequent recovery following rehydration. The would allow for the preparation of sensors with extended shelf lives, only requiring the addition of water for activation. By understanding and subsequently employing the tactics used by desiccation-tolerant extremophiles, it may be possible to design stabilized mammalian cell-based biosensors. The approaches required to realize this goal are discussed and illustrated with several examples.

Focus on function in geriatric assessment and rehab

In 1994, the province of Alberta, driven by the need for deficit reduction, began a major restructuring of the provincial health care system. An integral component of this new health structure was accountability for service delivery, including the use of outcome measures to determine service effectiveness. This paper describes the efforts of one program to evaluate the effectiveness of its service delivery, in terms of functional patient outcomes, in the midst of restructuring and budget constraints.

Vancomycin-resistant enterococci in intensive-care hospital settings: transmission dynamics, persistence, and the impact of infection control programs

Vancomycin-resistant enterococci (VRE) recently have emerged as a nosocomial pathogen especially in intensive-care units (ICUs) worldwide. Transmission via the hands of health-care workers is an important determinant of spread and persistence in a VRE-endemic ICU. We describe the transmission of nosocomial pathogens by using a micro-epidemiological framework based on the transmission dynamics of vector-borne diseases. By using the concept of a basic reproductive number, R0, defined as the average number of secondary cases generated by one primary case, we show quantitatively how infection control measures such as hand washing, cohorting, and antibiotic restriction affect nosocomial cross-transmission. By using detailed molecular epidemiological surveillance and compliance monitoring, we found that the estimated basic reproductive number for VRE during a study at the Cook County Hospital, Chicago, was approximately 3-4 without infection control and 0.7 when infection control measures were included. The impact of infection control was to reduce the prevalence from a predicted 79% to an observed 36%. Hand washing and staff cohorting are the most powerful control measures although their efficacy depends on the magnitude of R0. Under the circumstances tested, endemicity of VRE was stabilized despite infection control measures, by the constant introduction of colonized patients. Multiple stochastic simulations of the model revealed excellent agreement with observed pattern. In conjunction with detailed microbiological surveillance, a mathematical framework provides a precise template to describe the colonization dynamics of VRE in ICUs and impact of infection control measures. Our analyses suggest that compliance for hand washing significantly in excess of reported levels, or the cohorting of nursing staff, are needed to prevent nosocomial transmission of VRE in endemic settings.

External sources of vancomycin-resistant enterococci for intensive care units

OBJECTIVE

The incidence of colonization and infection with vancomycin-resistant enterococci (VRE) has increased dramatically in the last 5 yrs, especially in intensive care units (ICUs). We studied VRE-colonization in patients on admission to a medical ICU (MICU) where VRE colonization is endemic.

DESIGN

Prospective, descriptive analysis.

SETTING

An MICU of a public hospital.

PATIENTS

Three hundred and one consecutively admitted patients.

MEASUREMENTS AND MAIN RESULTS

Rectal swabs were obtained on admission from all patients. VRE isolates from all colonized patients were genetically fingerprinted by pulsed-field gel-electrophoresis (PFGE). Forty-three (14%) of 301 patients were colonized with VRE on MICU admission. Three (7%) of these 43 patients were admitted directly from the community without prior hospital contact. Risk of colonization on admission was related to the length of stay in the hospital before MICU-admission (odds ratio 4.65 for patients with a stay of at least 3 days) and previous in-hospital use of antibiotics. Of 22 VRE PFGE strain types recognized in the MICU during the study period, four (18%) were introduced by patients admitted directly from the community and ten (45%) were introduced by patients admitted from other hospital wards.

CONCLUSIONS

These results show that although ICUs are considered epicenters for antibiotic resistance, sources extraneous to our MICU (e.g., other wards) contributed the majority of VRE strain types in the unit.

Evaluating the FONE FIM: Part I. Construct validity

Rasch analysis was used in this paper to evaluate the Motor component of the FONE FIM, the telephone version of the Functional Independence Measure (FIM). For this purpose, 132 patients discharged from an inpatient geriatric assessment and rehabilitation program were assessed by trained research assistants using the FONE FIM. The results at 5 weeks post-discharge were compared to the observation FIMs (OBS FIMs) done at home 6 weeks post-discharge. These patients had an average age of 79 years and presented with multiple, complex medical problems and significant functional decline. The FONE FIM and the OBS FIM were shown to share a strikingly similar item hierarchy, based on Rasch item difficulty measures. Only bladder management and climbing stairs were misfitting items as indicated by item fit statistics. The same 13-item set and 4-point scales were shown to be psychometrically optimal for both the FONE FIM and the OBS FIM based on the person separation index. Further research is required to address the issue of the optimal item set and scale levels from psychometric and clinical perspectives.

The role of "colonization pressure" in the spread of vancomycin-resistant enterococci: an important infection control variable

OBJECTIVE

The spread of nosocomial multiresistant microorganisms is affected by compliance with infection control measures and antibiotic use. We hypothesized that "colonization pressure" (ie, the proportion of other patients colonized) also is an important variable. We studied the effect of colonization pressure, compliance with infection control measures, antibiotic use, and other previously identified risk factors on acquisition of colonization with vancomycin-resistant enterococci (VRE).

METHODS

Rectal colonization was studied daily for 19 weeks in 181 consecutive patients who were admitted to a single medical intensive care unit. A statistical model was created using a Cox proportional hazards regression model including length of stay in the medical intensive care unit until acquisition of VRE, colonization pressure, personnel compliance with infection control measures (hand washing and glove use), APACHE (Acute Physiology and Chronic Health Evaluation) 11 scores, and the proportion of days that a patient received vancomycin or third-generation cephalosporins, sucralfate, and enteral feeding.

RESULTS

With survival until colonization with VRE as the end point, colonization pressure was the most important variable affecting acquisition of VRE (hazard ratio [HR], 1.032; 95% confidence interval [C1], 1.012-1.052; P=.002). In addition, enteral feeding was associated with acquisition of VRE (HR, 1.009; 95% CI, 1.000-1.017; P=.05), and there was a trend toward association of third-generation cephalosporin use with acquisition (HR, 1.007; 95% CI, 0.999-1.015; P=.11). The effects of enteral feeding and third-generation cephalosporin use were more important when colonization pressure was less than 50%. Once colonization pressure was 50% or higher, these other variables hardly affected acquisition of VRE.

CONCLUSIONS

Acquisition of VRE was affected by colonization pressure, the use of antibiotics, and the use of enteral feeding. However, once colonization pressure was high, it became the major variable affecting acquisition of VRE.

Skin colonization with vancomycin-resistant enterococci among hospitalized patients with bacteremia

To assess the prevalence of skin and rectal colonization by vancomycin-resistant enterococci (VRE) in hospitalized bacteremic patients and to determine the relation between colonization and bacteremia, we compared 14 case patients who had bacteremia due to VRE with 30 control patients who had bacteremia due to other pathogens. Rectal colonization and skin (inguinal area and/or antecubital fossa) colonization with VRE were common among both case patients (100% had rectal colonization, and 86% had skin colonization) and control patients (37% had rectal colonization and 23% had skin colonization). Among patients with rectal colonization, skin colonization was more common when diarrhea or fecal incontinence was present. The bloodstream cleared without appropriate antimicrobial therapy in nine of the 14 patients with bacteremia due to VRE. The high prevalence of skin colonization with VRE may increase the risk of catheter-related sepsis, cross-infection, or blood culture contamination (which may explain the frequent spontaneous resolution of bacteremia due to VRE).

Epidemiology of colonisation of patients and environment with vancomycin-resistant enterococci

BACKGROUND

Vancomycin-resistant enterococci (VRE) have emerged as nosocomial pathogens during the past 5 years, but little is known about the epidemiology of VRE. We investigated colonisation of patients and environmental contamination with VRE in an endemic setting to assess the importance of different sources of colonisation.

METHODS

Between April 12, and May 29, 1995, cultures from body sites (rectum, groin, arm, oropharynx, trachea, and stomach) and from environmental surfaces (bedrails, drawsheet, blood-pressure cuff, urine containers, and enteral feed) were obtained daily from all newly admitted ventilated patients in our medical intensive-care unit (MICU). Rectal cultures were obtained from all non-ventilated patients in the MICU. Strain types of VRE were determined by pulsed-field gel electrophoresis.

FINDINGS

There were 97 admissions of 92 patients, of whom 38 required mechanical ventilation. Colonisation with VRE on admission was more common in ventilated than in non-ventilated patients (nine [24%] vs three [6%], p < 0.05). Of the nine ventilated patients colonised with VRE on admission, one acquired a new strain of VRE in the MICU. Of the 29 ventilated patients who were not colonised with VRE on admission, 12 (41%) acquired VRE in the MICU. The median time to acquisition of VRE was 5 days (interquartile range 3-8). Of the 13 ventilated patients who acquired VRE, 11 (85%) were colonised with VRE by cross-colonisation. VRE were isolated from 157 (12%) of 1294 environmental cultures. The rooms of 13 patients were contaminated with VRE, but only three (23%) of these patients subsequently acquired colonisation with VRE. Pulsed-field gel electrophoresis of 262 isolates showed 20 unique strain types of VRE.

INTERPRETATION

Frequent colonisation with VRE on MICU admission and subsequent cross-colonisation are important factors in the endemic spread of VRE. Persistent VRE colonisation in the gastrointestinal tract and on the skin, the presence of multiple-strain types of VRE, and environmental contamination may all contribute to the spread of VRE.

Work force diversity: nursing perspectives

All too frequently, diversity is viewed negatively or, at best, neutrally. The challenge of diversity is one of embracing it. The extent to which we are successful in meeting this challenge will determine South Carolina's and America's competitiveness and effectiveness in health care and in the global marketplace. Although much of the focus of this article has been work force diversity within nursing, attention to diversity is applicable within all health services markets, where human resources is the primary conduit for progress. Therefore, elements of this report can be generalized to all health care providers, where racial under-representation, in comparison to the populations served, is present.

A comparison of the effect of universal use of gloves and gowns with that of glove use alone on acquisition of vancomycin-resistant enterococci in a medical intensive care unit

OBJECTIVE

To determine the efficacy of the use of gloves and gowns compared with that of the use of gloves alone for the prevention of nosocomial transmission of vancomycin-resistant enterococci.

DESIGN

Epidemiologic study and controlled, nonrandomized clinical trial.

SETTING

University-affiliated, 900-bed, urban teaching hospital in which vancomycin-resistant enterococci are endemic.

PATIENTS

181 consecutive patients admitted to the medical intensive care unit for 48 hours or more.

INTERVENTION

It was determined that all hospital employees would always use gloves and gowns when attending 8 particular beds in the medical intensive care unit and would always use gloves alone when attending 8 others. Compliance with precautions was monitored weekly. Rectal surveillance cultures were taken from patients daily. Cultures of environmental surfaces, such as those of bed rails, bedside tables, and other frequently touched objects in patient rooms and common areas, were taken monthly. Pulsed-field gel electrophoresis was used for molecular epidemiologic typing of vancomycin-resistant enterococci.

MEASUREMENTS

The number of patients becoming colonized by vancomycin-resistant enterococci; the number of days to acquisition of vancomycin-resistant enterococci; and other measurements, including nosocomial infections, length of hospital stay, and mortality rates.

RESULTS

The 93 patients in glove-and-gown rooms and the 88 patients in glove-only rooms had similar demographic and clinical characteristics. Fifteen (16.1%) patients in the glove-and-gown group and 13 (14.8%) in the glove-only group had vancomycin-resistant enterococci on admission to the medical intensive care unit. Twenty-four (25.8%) patients in the glove-and-gown group and 21 (23.9%) in the glove-only group acquired vancomycin-resistant enterococci in the medical intensive care unit. The mean times to colonization among the patients who became colonized were 8.0 days in the glove-and-gown group and 7.1 days in the glove-only group. None of these comparisons were statistically significant. Risk factors for acquisition of vancomycin-resistant enterococci induced length of stay in the medical intensive care unit, use of enteral feeding, and use of sucralfate. Compliance with precautions was 79% in glove-and-gown rooms and 62% in glove-only rooms (P < 0.001). Only 25 of 397 (6.3%) environmental cultures were positive for vancomycin-resistant enterococci. Nineteen types of vancomycin-resistant enterococci were documented by pulsed-field gel electrophoresis during the study period.

CONCLUSIONS

Universal use of gloves and gowns was no better than universal use of gloves only in preventing rectal colonization by vancomycin-resistant enterococci in a medical intensive care unit of a hospital in which vancomycin-resistant enterococci are endemic. Because the use of gowns and gloves together may be associated with better compliance and may help prevent transmission of other infectious agents, this finding may not be applicable to outbreaks caused by single strains or hospitals in which the prevalence of vancomycin-resistant enterococci is low.

Serial measurement of serum C-reactive protein facilitates evaluation in alcoholic hepatitis

BACKGROUND/AIMS

An ability to measure inflammatory activity in alcoholic hepatitis is desirable for assessing its natural history and therapeutic responses, but convenient and simple parameters are lacking. To determine whether acute phase proteins could be useful for this purpose, we studied serum CRP and several other acute phase proteins in a series of patients with alcoholic hepatitis.

MATERIALS AND METHODS

We examined sequential sera from 72 patients with serum bilirubin greater than 5 mg/dl.

RESULTS

The short-term mortality during the approximately 30 day study period was 18%. There was moderate to marked elevation of serum c-reactive protein at initial testing in all patients with alcoholic hepatitis. In consecutive sera within the first week of testing, a further rise in c-reactive protein was noted significantly more frequently among patients that did not survive subsequently. Serum c-reactive protein levels gradually declined in recovering patients but were still abnormal at the end of the study period. In contrast, serum haptoglobin levels were subnormal initially, as well as throughout the subsequent short-term course. Among other acute phase proteins, serum ceruloplasmin, transferrin, a-1 acid glycoprotein and a-2 macroglobulin remained in the normal range.

CONCLUSIONS

These results suggest that the expression of c-reactive protein but not haptoglobin is upregulated in alcohol-induced acute liver injury. Serial measurements of serum c-reactive protein should be useful in assessing the clinical activity of alcoholic hepatitis.

Staphylococcus aureus septic arthritis in patients on hemodialysis treatment

We retrospectively reviewed hospital discharge diagnoses of septic arthritis over an 11-year period (1982 through 1992) at 3 medical centers; 11 episodes of septic arthritis were identified in patients on hemodialysis treatment. Of the 11 episodes, 9 were caused by Staphylococcus aureus; in 8 of 9, the blood cultures were positive for the organism and the infection was monoarticular. Concurrent infection of the dialysis access site occurred in 4 cases. Two patients died (22%). We postulate that repeated skin trauma and contact with health care personnel and facilities result in a high rate of nasal carriage of S aureus and, hence, an increased risk of bacteremia with its attendant complications such as septic arthritis. The use of mupirocin nasal ointment is reported to eradicate or suppress carriage in a high percentage of patients; some studies report that long-term suppressive therapy reduces the frequency of S aureus bacteremia.

The lutropin beta-subunit N-terminus facilitates subunit combination by offsetting the inhibitory effects of residues needed for LH activity

Human chorionic gonadotropin (hCG) contains a beta-subunit N-terminal amino acid extension that contacts the alpha-subunit and is needed for efficient alpha and hCG beta-subunit combination. Here we report that an hCG beta-subunit analog, lacking residues 2-8, combined with the alpha-subunit more efficiently when positively charged residues between beta-subunit cysteines 10 and 11 were replaced with negatively charged residues found in the corresponding portion of follitropin. Residues 2-8 had no influence on binding of hCG to lutropin receptors. Positive charges between cysteines 10 and 11 are essential for high affinity binding of lutropins to their receptors. Therefore, the N-terminal extension found in all lutropin beta-subunits appears to have evolved to offset the inhibition of subunit combination by beta-subunit residues that are essential for lutropin activity. This beta-subunit extension is not found in follitropins or thyrotropins, hormones that have negatively charged residues between cysteines 10 and 11.

Incorporation of 14C-galactose into gangliosides of rabbit lens

Rabbit lenses were incubated in organ culture with 14C-galactose for 6, 12 and 20 hours. Gangliosides were extracted using the Folch-Suzuki method, purified by dialysis and analyzed by thin-layer chromatography. Six radioactive bands, including the origin, were observed. Tentative identification of these bands as N-acetylneuraminylgalactosylglucosylceramide (GM3), N-acetylgalactosaminyl-(N-acetylneuraminyl)-galactosylglucosylceramide (GM2), galactosyl-N-acetylgalactosaminyl-(N-acetylneuraminyl)- galactosylglucosylceramide (GM1), N-acetylneuraminylgalactosyl-N- acetylgalactosaminyl-(N-acetylneuraminyl)-galactosylglucosylceramide (GD1a), N-acetylneuraminylgalactosyl-N-acetylgalactosaminyl-(N- acetylneuraminyl-N-acetylneuraminyl)-galactosylglucosylceramide (GT) was made by comparison with authentic standard gangliosides. Galactose incorporation into GM3 and GM2 increased during the first 12 hours but decreased during the period from 12 to 20 hours. GD1a and GT incorporated the greatest amount of label during the period from 12 to 20 hours. Incorporation of labeled galactose into GM1 was nearly constant during this time period. Specific activities for GM1, GM3 and GT were nearly the same at 6 hours and were about half those of GM2 and GD1a for the same time period.

Quantitative estimation of secretory immunoglobulin A by radial immunodiffusion technique

A single radial diffusion system in agar gel, which can be used for the quantitative measurement of secretory immunoglobulin A in solutions and in biological fluids, is discussed. Concentrations of secretory immunoglobulin A as low as 0.095 mg/ml were measured successfully using a 2 mul sample volume. Conditions that achieve maximum sensitivity and precision, such as gel concentration, incubation time, and temperature, are described.