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Biomedical subjects

M J Richards

Publications and source records attributed to M J Richards.

At least 19 recordsLinked to original sources
PubMed2006

Compliance with surgical antibiotic prophylaxis--reporting from a statewide surveillance programme in Victoria, Australia.

A statewide assessment of the compliance of surgical antibiotic prophylaxis (SAP) with guidelines was undertaken for large public hospitals in Victoria, Australia. This was carried out using data collected as part of a surveillance system for hospital-acquired infections. The study population comprised patients in Victorian public hospitals with >100 beds (N=27) undergoing cardiac surgical procedures, hip or knee arthroplasty, cholecystectomy, appendectomy, colon surgery or hysterectomy over a 21-month period. Australian guidelines recommend SAP for all 10 643 surgical procedures included in this study. Combining all procedures, 87% received SAP, the choice of antibiotic was concordant with guidelines for 53.3% of procedures, and the choice of antibiotic was considered to be 'adequate but not concordant' for 23.9% of procedures. SAP was considered to be inadequate for 18.9% of procedures. A large number of antibiotic regimens were utilized for cardiac and orthopaedic surgery. Documentation of timing of administration was not submitted for more than half of all procedures. Timing was concordant with guidelines for 76.4% of procedures when documented. Prophylactic antibiotic choice was generally more concordant with guidelines for cardiac and orthopaedic procedures than for other types of surgery. However, even for these procedures, where infections carry high morbidity, SAP was sometimes inadequate. Regular reporting on SAP compliance from data collected during surveillance for hospital-acquired infections is achievable. This should lead to improvements in both compliance and documentation.

Anti-Bacterial Agents↗
PubMed2001

The efficacy of continuous infusion flucloxacillin in home therapy for serious staphylococcal infections and cellulitis.

The efficacy and safety of continuous infusion flucloxacillin as home-based treatment was assessed in 62 consecutive patients with proven serious methicillin-susceptible Staphylococcus aureus (MSSA) infections (n = 36) and cellulitis (n = 26). The treatment was well tolerated and resulted in cure or adequate suppression of infection in 27 of 28 (96%) patients in the serious MSSA infection group, and in 24 of 26 (92%) patients in the cellulitis group.

Adult↗
PubMed2000

Cholesterol synthesis in the vertebrate retina: effects of U18666A on rat retinal structure, photoreceptor membrane assembly, and sterol metabolism and composition.

Treatment of neonatal rats with U18666A, an inhibitor of desmosterol delta24-reductase, results in accumulation of desmosterol (delta5,24) and depletion of cholesterol (delta5) in various bodily tissues and also causes cataracts. We evaluated the effects of U18666A on the sterol composition, de novo sterol synthesis, and histological structure of the retina. Neonatal Sprague-Dawley rats were injected subcutaneously with U18666A (15 mg/kg, in olive oil ) every other day from birth through 3 wk of age; in parallel, control rats received olive oil alone. At 21 d, treated and control groups each were subdivided into two groups: one group of each was injected intravitreally with [3H]acetate; retinas were removed 20 h later and nonsaponifiable lipids (NSL) were analyzed by radio-high-performance liquid chromatography. The other group was injected intravitreally with [3H]leucine; 4 d later, one eye of each animal was evaluated by light and electron microscopy and light microscopic autoradiography, while contralateral retinas and rod outer segment (ROS) membranes prepared therefrom were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis/fluorography. In the treated group, the delta5/delta5,24 mole ratio of retinas was ca. 1.0, and >88% of the NSL radioactivity was in delta5,24; in contrast, control retinas had delta5/delta5,24 >170, with >80% of the NSL radioactivity in delta5. Retinal histology, ultrastructure, ROS renewal rates, and rhodopsin synthesis and intracellular trafficking were comparable in both treated and control animals. These results suggest that desmosterol can either substitute functionally for cholesterol in the retina or it can complement subthreshold levels of cholesterol by sterol synergism.

Acetates↗
PubMed2000

Retinal structure and function in an animal model that replicates the biochemical hallmarks of desmosterolosis.

Desmosterolosis is a rare, autosomal recessive, human disease characterized by multiple congenital anomalies in conjunction with grossly elevated levels of desmosterol and markedly reduced levels of cholesterol in all bodily tissues. Herein, we evaluated retinal sterol composition, histology, and electrophysiological function in an animal model that exhibited the biochemical features of desmosterolosis, produced by treating pregnant rats and their progeny with U18666A, an inhibitor of desmosterol reductase. Treated rats had cataracts, were substantially smaller, and had markedly high levels of desmosterol and profoundly low levels of cholesterol in their retinas and other tissues compared to age-matched controls. However, their retinas were histologically normal and electrophysiologically functional. These results suggest that desmosterol may be able to replace cholesterol in the retina, both structurally and functionally. These findings are discussed in the context of "sterol synergism".

Abnormalities, Multiple↗
PubMed2000

Nosocomial infections in combined medical-surgical intensive care units in the United States.

OBJECTIVE: To describe the epidemiology of nosocomial infections in combined medical-surgical (MS) intensive care units (ICUs) participating in the National Nosocomial Infection Surveillance (NNIS) System. DESIGN: Analysis of surveillance data on 498,998 patients with 1,554,070 patient-days, collected between 1992 and 1998 from 205 MS ICUs following the NNIS Intensive Care Unit protocol, representing 152 participating NNIS hospitals in the United States. RESULTS: Infections at three major sites represented 68% of all reported infections (nosocomial pneumonia, 31%; urinary tract infections (UTIs), 23%; and primary bloodstream infections (BSIs), 14%: 83% of episodes of nosocomial pneumonia were associated with mechanical ventilation, 97% of UTIs occurred in catheterized patients, and 87% of primary BSIs in patients with a central line. In patients with primary BSIs, coagulase-negative staphylococci (39%) were the most common pathogens reported; Staphylococcus aureus (12%) was as frequently reported as enterococci (11%). Coagulase-negative staphylococcal BSIs were increasingly reported over the 6 years, but no increase was seen in candidemia or enterococcal bacteremia. In patients with pneumonia, S. aureus (17%) was the most frequently reported isolate. Of reported isolates, 59% were gram-negative bacilli. In patients with UTIs, Escherichia coli (19%) was the most frequently reported isolate. Of reported isolates, 31% were fungi. In patients with surgical-site infections, Enterococcus (17%) was the single most frequently reported pathogen. Device-associated nosocomial infection rates for BSIs, pneumonia, and UTIs did not correlate with length of ICU stay, hospital bed size, number of beds in the ICU, or season. Combined MS ICUs in major teaching hospitals had higher device-associated infection rates compared to all other hospitals with combined medical-surgical units. CONCLUSIONS: Nosocomial infections in MS ICUs at the most frequent infection sites (bloodstream, urinary, and respiratory tract) almost always were associated with use of an invasive device. Device-associated infection rates were the best available comparative rates between combined MS ICUs, but the distribution of device-associated rates should be stratified by a hospital's major teaching affiliation status.

Cross Infection↗
PubMed1999

Nosocomial infections in medical intensive care units in the United States. National Nosocomial Infections Surveillance System.

OBJECTIVE: To describe the epidemiology of nosocomial infections in medical intensive care units (ICUs) in the United States. DESIGN: Analysis of ICU surveillance data collected through the National Nosocomial Infections Surveillance (NNIS) System between 1992 and 1997. SETTING: Medical ICUs in the United States. PATIENTS: A total of 181,993 patients. MEASUREMENTS AND MAIN RESULTS: Nosocomial infections were analyzed by infection site and pathogen distribution. Urinary tract infections were most frequent (31%), followed by pneumonia (27%) and primary bloodstream infections (19%). Eighty-seven percent of primary bloodstream infections were associated with central lines, 86% of nosocomial pneumonia was associated with mechanical ventilation, and 95% of urinary tract infections were associated with urinary catheters. Coagulase-negative staphylococci (36%) were the most common bloodstream infection isolates, followed by enterococci (16%) and Staphylococcus aureus (13%). Twelve percent of bloodstream isolates were fungi. The most frequent isolates from pneumonia were Gram-negative aerobic organisms (64%). Pseudomonas aeruginosa (21%) was the most frequently isolated of these. S. aureus (20%) was isolated with similar frequency. Candida albicans was the most common single pathogen isolated from urine and made up just over half of the fungal isolates. Fungal urinary infections were associated with asymptomatic funguria rather than symptomatic urinary tract infections (p < .0001). Certain pathogens were associated with device use: coagulase-negative staphylococci with central lines, P. aeruginosa and Acinetobacter species with ventilators, and fungal infections with urinary catheters. Patient nosocomial infection rates for the major sites correlated strongly with device use. Device exposure was controlled for by calculating device-associated infection rates for bloodstream infections, pneumonia, and urinary tract infections by dividing the number of device-associated infections by the number of days of device use. There was no association between these device-associated infection rates and number of hospital beds, number of ICU beds, or length of stay. There is a considerable variation within the distribution of each of these infection rates. CONCLUSIONS: The distribution of sites of infection in medical ICUs differed from that previously reported in NNIS ICU surveillance studies, largely as a result of anticipated low rates of surgical site infections. Primary bloodstream infections, pneumonia, and urinary tract infections associated with invasive devices made up the great majority of nosocomial infections. Coagulase-negative staphylococci were more frequently associated with primary bloodstream infections than reported from NNIS ICUs of all types in the 1980s, and enterococci were a more frequent isolate from bloodstream infections than S. aureus. Fungal urinary tract infections, often asymptomatic and associated with catheter use, were considerably more frequent than previously reported. Invasive device-associated infections were associated with specific pathogens. Although device-associated site-specific infection rates are currently our most useful rates for performing comparisons between ICUs, the considerable variation in these rates between ICUs indicates the need for further risk adjustment.

Adult↗
PubMed1999

Nosocomial infections in pediatric intensive care units in the United States. National Nosocomial Infections Surveillance System.

OBJECTIVES: To describe the epidemiology of nosocomial infections in pediatric intensive care units (ICUs) in the United States. BACKGROUND: Patient and ICU characteristics in pediatric ICUs suggest the pattern of nosocomial infections experienced may differ from that seen in adult ICUs. METHODS: Data were collected between January 1992 and December 1997 from 61 pediatric ICUs in the United States using the standard surveillance protocols and nosocomial infection site definitions of the National Nosocomial Infections Surveillance System's ICU surveillance component. RESULTS: Data on 110 709 patients with 6290 nosocomial infections were analyzed. Primary bloodstream infections (28%), pneumonia (21%), and urinary tract infections (15%) were most frequent and were almost always associated with use of an invasive device. Primary bloodstream infections and surgical site infections were reported more frequently in infants aged 2 months or less as compared with older children. Urinary tract infections were reported more frequently in children >5 years old compared with younger children. Coagulase-negative staphylococci (38%) were the most common bloodstream isolates, and aerobic Gram-negative bacilli were reported in 25% of primary bloodstream infections. Pseudomonas aeruginosa (22%) was the most common species reported from pneumonia and Escherichia coli (19%), from urinary tract infections. Enterobacter spp. were isolated with increasing frequency from pneumonia and were the most common Gram-negative isolates from bloodstream infections. Device-associated infection rates for bloodstream infections, pneumonia, and urinary tract infections did not correlate with length of stay, the number of hospital beds, or season. CONCLUSIONS: In pediatric ICUs, bloodstream infections were the most common nosocomial infection. The distribution of infection sites and pathogens differed with age and from that reported from adult ICUs. Device-associated infection rates were the best rates currently available for comparisons between units, because they were not associated with length of stay, the number of beds in the hospital, or season.

Adolescent↗
PubMed1999

Marked alteration of sterol metabolism and composition without compromising retinal development or function.

PURPOSE: To evaluate the consequences of altering retinal sterol metabolism and composition on the development, histologic organization, and electrophysiological function of the retina, under conditions that mimic the biochemical hallmarks of the Smith-Lemli-Opitz (SLO) syndrome. METHODS: Pregnant Sprague-Dawley rats were fed cholesterol-free chow containing AY9944 (treated group), an inhibitor of 3beta-hydroxysterol delta7-reductase, from gestational day 6 through postnatal day (P)28. Control animals were fed the same chow, but without AY9944. In addition, progeny in the treated group were injected subcutaneously every other day from birth to P28 with an olive oil emulsion containing AY9944; control animals received olive oil emulsion alone. At various postnatal times, tissues from treated and control animals were harvested, and their sterol profiles were analyzed by reversed-phase high-performance liquid chromatography. Companion eyes from animals of both groups were examined histologically at P1. At P28, animals were evaluated by electroretinography; tissues were then harvested for biochemical analysis and companion eyes were subjected to histologic and ultrastructural analyses. RESULTS: Treatment of developing rats with AY9944 caused markedly abnormal accumulation of 7-dehydrosterols and severely reduced cholesterol levels in all tissues examined, relative to control animals. Despite this, treated animals exhibited normal retinal development and had no overt ocular defects or decrease in electroretinographic function, up to P28. CONCLUSIONS: These results were unexpected, given the known biophysical effects of such sterol alterations on membrane properties and the profound dysmorphic and cognitive abnormalities associated with genetic defects in 3beta-hydroxysterol delta7-reductase that have been linked to the SLO syndrome. The results suggest that 7-dehydrosterols can substitute functionally for cholesterol in the retina or perhaps can act synergistically with subthreshold levels of residual cholesterol to allow normal cellular structure and function to be achieved.

Animals↗
PubMed1998

Nosocomial infections in coronary care units in the United States. National Nosocomial Infections Surveillance System.

To describe the epidemiology of nosocomial infections in Coronary Care Units (CCUs) in the United States, we analyzed data collected between 1992 and 1997 using the standard protocols of the National Nosocomial Infections Surveillance (NNIS) Intensive Care Unit (ICU) surveillance component. Data on 227,451 patients with 6,698 nosocomial infections were analyzed. Urinary tract infections (35%), pneumonia (24%), and primary bloodstream infections (17%) were almost always associated with use of an invasive device (93% with a urinary catheter, 82% with a ventilator, 82% with a central line, respectively). The distribution of pathogens differed from that reported from other types of ICUs. Staphylococcus aureus (21%) was the most common species reported from pneumonia and Escherichia coli (27%) from urine. Only 10% of reported urine isolates were Candida albicans. S. aureus (24%) was the more common bloodstream isolate than enterococci (10%). The mean overall patient infection rate was 2.7 infections per 100 patients. Device-associated infection rates for bloodstream infections, pneumonia, and urinary tract infections did not correlate with length of stay, number of hospital beds, number of CCU beds, or the hospital teaching affiliation, and were the best rates for comparisons between units. Use of invasive devices was lower than in other types of ICUs. Overall patient infection rates were lower than in other types of ICUs, which is largely explained by lower rates of invasive device usage.

Adult↗
PubMed1997

Universal precautions: attitudes of Australian and New Zealand anaesthetists.

OBJECTIVE: To survey the attitudes of a group of Australasian anaesthetists to the risks of bloodborne infections, and their understanding of Universal Precautions. DESIGN: A questionnaire survey. SETTING: A conference on health risks to anaesthetists in August 1995. PARTICIPANTS: 162 Australian and New Zealand anaesthetists. RESULTS: Two-thirds of anaesthetists favoured preoperative HIV and hepatitis B and C testing; they rarely took "risk" histories from patients preoperatively. Only 37% always wore gloves while administering anaesthetics, and 67% reported they resheathed needles. Thirty-nine per cent had had needlestick injuries in the preceding 12 months; 43% did not always report them. The perceived needlestick accident rate was 1 in 1300 anaesthetics. Most (90%) were immunised against hepatitis B, but 20% of these had never had their serological response checked. Twelve per cent of anaesthetists had had occupational exposure to HIV. A high proportion of the anaesthetists understood the principles of Universal Precautions, but only half of them believed these to be practical. CONCLUSIONS: The current situation of Australasian anaesthetists not complying with Universal Precautions and not taking a risk history for bloodborne pathogens may carry the greatest risk of accidental infection.

Acquired Immunodeficiency Syndrome↗
PubMed1997

In vitro metabolic competence of the frog retina: effects of glucose and oxygen deprivation.

The metabolic competence and histological integrity of the frog retina in vitro were evaluated as a function of the presence/absence of exogenous glucose and of oxygen tension. Dark- and light-adapted frog neural retinas were incubated for 1-8 hr at 23 degrees C in a modified Ringer's-bicarbonate medium under aerobic and anaerobic conditions, in the presence and absence of 10 mM glucose. Control retinas (+glucose, aerobic conditions) maintained ATP levels comparable to those of freshly excised tissue (ave. 17 nmol mg protein-1), produced minimal lactate (ave. 0.12 mumol mg protein-1 hr-1), and exhibited normal histology. In the absence of any exogenous carbon source, retinas incubated aerobically maintained ATP levels, produced lactate, incorporated [3H]acetate into nonsaponifiable lipids, and exhibited histology comparable to controls. In the presence of 1 mM iodoacetate, aerobic ATP levels declined markedly, with or without exogenous glucose. Under anaerobic conditions with glucose present, lactate production increased ca. 8.5-fold, while ATP levels were maintained at control levels, demonstrating a marked Pasteur effect; under these conditions, retinas exhibited only moderate histopathological changes. However, in the absence of both glucose and oxygen, ATP levels declined precipitously, with concomitant massive cytological deterioration. No major differences in the biochemical measurements or histological appearance were observed as a function of light adaptation. These results demonstrate the remarkable resilience of the frog retina to anoxia and hypoglycemic stress. Aerobically, with or without exogenous glucose, ATP production and de novo lipid synthesis are maintained, apparently by recruitment of an endogenous carbohydrate substrate (e.g., glycogen).

Adenosine Triphosphate↗
PubMed1997

Radiation therapy for squamous cell carcinoma in dystrophic epidermolysis bullosa: case reports and literature review.

Dystrophic epidermolysis bullosa (DEB) is a debilitating systemic disease frequently associated with biologically aggressive secondary squamous cell carcinomas arising from affected skin or mucosal surfaces. Treatment of these carcinomas with surgery, chemotherapy, or radiation is complicated by inherently poor wound healing. We report on two DEB patients treated with radiation therapy for locally advanced squamous cell carcinoma, and retrospectively analyze 10 DEB patients treated with radiation, reported in the literature. Of the 11 fully available and described case results from radiation therapy, six (54%) patients demonstrated a partial tumor response. All patients receiving > 4,500 cGy developed moist skin desquamation and delayed skin healing. Radiation therapy may be of benefit in palliating DEB patients who have locally advanced carcinoma, but has been associated with enhanced normal tissue toxicity, suggesting a narrow or absent therapeutic index between irradiated carcinoma and skin.

Adult↗