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Biomedical subjects

J F Black

Publications and source records attributed to J F Black.

9 recordsLinked to original sources
PubMed2006

A prospective comparison of severity scores for identifying patients with severe community acquired pneumonia: reconsidering what is meant by severe pneumonia.

BACKGROUND: Several severity scores have been proposed to predict patient outcome and to guide initial management of patients with community acquired pneumonia (CAP). Most have been derived as predictors of mortality. A study was undertaken to compare the predictive value of these tools using different clinically meaningful outcomes as constructs for "severe pneumonia". METHODS: A prospective cohort study was performed of all patients presenting to the emergency department with an admission diagnosis of CAP from March 2003 to March 2004. Clinical and laboratory features at presentation were used to calculate severity scores using the pneumonia severity index (PSI), the revised American Thoracic Society score (rATS), and the British Thoracic Society (BTS) severity scores CURB, modified BTS severity score, and CURB-65. The sensitivity, specificity, positive and negative predictive values were compared for four different outcomes (death, need for ICU admission, and combined outcomes of death and/or need for ventilatory or inotropic support). RESULTS: 392 patients were included in the analysis; 37 (9.4%) died and 26 (6.6%) required ventilatory and/or inotropic support. The modified BTS severity score performed best for all four outcomes. The PSI (classes IV+V) and CURB had a very similar performance as predictive tools for each outcome. The rATS identified the need for ICU admission well but not mortality. The CURB-65 score predicted mortality well but performed less well when requirement for ICU was included in the outcome of interest. When the combined outcome was evaluated (excluding patients aged >90 years and those from nursing homes), the best predictors were the modified BTS severity score (sensitivity 94.3%) and the PSI and CURB score (sensitivity 83.3% for both). CONCLUSIONS: Different severity scores have different strengths and weaknesses as prediction tools. Validation should be done in the most relevant clinical setting, using more appropriate constructs of "severe pneumonia" to ensure that these potentially useful tools truly deliver what clinicians expect of them.

Adolescent↗
PubMed2001

Cooperative phenomena in two-pulse, two-color laser photocoagulation of cutaneous blood vessels.

A novel laser system has been developed to study the effects of multiple laser pulses of differing wavelengths on cutaneous blood vessels in vivo, using the hamster dorsal skin flap preparation and in vitro, using cuvettes of whole or diluted blood. The system permits sequenced irradiation with well-defined intrapulse spacing at 532 nm, using a long-pulse frequency-doubled Nd:YAG laser, and at 1064 nm, using a long-pulse Nd:YAG laser. Using this system, we have identified a parameter space where two pulses of different wavelengths act in a synergistic manner to effect permanent vessel damage at radiant exposures where the two pulses individually have little or no effect. Using a two-color pump-probe technique in vitro, we have identified a phenomenon we call greenlight-induced infrared absorption, where a pulse of green light causes photochemical and photothermal modifications to the chemical constituents of blood and results in enhanced infrared absorption. We identify a new chemical species, met-hemoglobin, not normally present in healthy human blood but formed during laser photocoagulation which we believe is implicated in the enhanced near-infrared absorption.

Animals↗
PubMed1978

Effects of glycopyrrolate and cimetidine on gastric volume and acidity in patients awaiting surgery.

Glycopyrrolate or cimetidine was administered before operation to patients undergoing elective surgery. After the induction of anaesthesia, the stomach contents were retrieved and the volume and pH measured. Neither drug diminished the volume of gastric contents compared with control. Glycopyrrolate produced little diminution in hydrogen ion concentration. Cimetidine caused a marked increase in pH with a mean [h+] 3.2 x 10(-3) g litre-1 compared with 1.4 x 10(-2) g litre-1 in the controls and 1.1 x 10(-2) g litre-1 in the glycopyrrolate group. Seventy-seven per cent of the patients receiving cimetidine had a pH greater than 2.5.

Cimetidine↗
PubMed1976

Laparoscopic sterilization with electrocautery, spring-loaded clips, and Silastic bands: technical problems and early complications.

Among 2283 patients, rates of technical failure, technical difficulty, and operative and early postoperative complications were evaluated for different methods of tubal occlusion at laparoscopy: electrocoagulation (980 cases), spring-loaded clip application (991 cases), and Silastic band application (312 cases). Rates of technical failure and technical difficulty at surgery were significantly higher (P less than 0.05) for the spring-loaded clip technique than for the electrocoagulation and Silastic band techniques. Mechanical and optical difficulties with the prototype spring clip applicator were the major sources of technical difficulties. Rates of operative (1.2%) and early postoperative (1.9%) complications were not significantly different for the three techniques of tubal occlusion. It is concluded that all three study techniques appear to be practical, and large, long-term, randomized, comparative studies to determine rates of failure and subsequent gynecologic problems are necessary to determine the best method of sterilization.

Electrocoagulation↗
PubMedDate not supplied

Gram-negative identification card for identification of Salmonella, Escherichia coli, and other Enterobacteriaceae isolated from foods: collaborative study.

Twelve laboratories evaluated the Gram-Negative Identification (GNI) Card to identify members of the Enterobacteriaceae. Eighty-four isolates, previously isolated from foods, were used in the collaborative study; the isolates represented 12 genera within the Enterobacteriaceae group. Each collaborator streaked each isolate on tryptic soy agar plates for purity. In the method, plates are incubated 18-24 h at 35 degrees C. Isolated colonies are then subcultured to tryptic soy agar slants and incubated 18-24 h at 35 degrees C. An emulsion is made from the growth on the slant in 1.8 mL 0.45% sodium chloride solution. The GNI Card is filled and placed in a reader/incubator. Isolates are identified and an identification is printed. The Vitek System correctly identified 96.7% of Salmonella sp., 97.0% of Escherichia coli, and an average of 93.8% of the other enteric genera. The method using the Vitek System and GNI Card has been approved interim official first action by AOAC as a screening method for the presumptive identification of Salmonella sp., E. coli, and other Enterobacteriaceae isolated from foods.

Culture Media↗
PubMedDate not supplied

Industry perspectives on Listeria monocytogenes.

Industry concerns and our ongoing research on Listeria are discussed in this report. Topics include sampling for analysis; sanitizers and their use in manufacturing facilities; precautions on use of the FDA method for Listeria; use of the Vitek Gram Positive Identification Card; and a brief discussion on findings of Listeria in environmental samples taken from the same site at the same time of year in 1986 and 1987.

Food Microbiology↗
PubMedDate not supplied

Intradural lumbar disk fragment with ring enhancement on MR.

Intradural extension of a herniated intervertebral disk, an unusual complication of a common disease, may mimic an intradural tumor on MR. A case of a pathologically proved subdural disk fragment is presented; MR findings that suggested the correct diagnosis were: proximity of intervertebral disk disease; whorl-like mixed intensity on T2-weighted images; poor visualization of the mass on unenhanced T1-weighted images; and marked ring enhancement following administration of gadolinium.

Diagnosis, Differential↗