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Biomedical subjects

R Collier

Publications and source records attributed to R Collier.

At least 19 recordsLinked to original sources
PubMed2003

Hyperbaric oxygen therapy of iatrogenic cerebral arterial gas embolism.

We describe our experience using HBO2 therapy for iatrogenic cerebral arterial gas embolism (CAGE) in this retrospective review of nineteen patients treated for iatrogenic CAGE, from 1987 to 1999. Immediately after treatment, five patients completely resolved all signs and symptoms, eleven had improvement, one had no change, and two were not assessable. Within two months post treatment, three additional patients completely resolved and six had further improvement. Patients with a venous source all experienced pulmonary signs or symptoms, with eight of nine chest x-rays demonstrating pulmonary edema. Patients with an arterial source had no pulmonary symptoms; all chest x-rays were clear. Imaging studies prior to HBO2 therapy demonstrated gas in six of 23 exams; five of the remaining 17 exams showed secondary changes consistent with gas embolism. Iatrogenic CAGE patients improved with HBO2 therapy, and improvement for some continued for several months. Patients with CAGE from a venous source have pulmonary signs or symptoms. Diagnosis of CAGE should be made on clinical suspicion without reliance on imaging studies.

Adolescent↗
PubMed2002

Investigation into the thermal distribution of microwave helical antennas designed for the treatment of Barrett's oesophagus.

A set of helical microwave antennas was designed to investigate their potential use in thermal therapy of Barrett's oesophagus. The antennas had a diameter of up to 3.3 mm and various lengths between 20 and 37 mm; these were designed to operate at 915 MHz. Sets of polytetrafluoroethylene (PTFE) formers were constructed to improve the repeatability and reproducibility of the helix manufacture. Small diameter copper wire was wound over the formers and connected to the coaxial cable at the inner and outer conductor junctions. The power deposition profiles of the antennas were measured in a muscle-equivalent phantom using an infrared camera. The effects of antenna length and coil spacing were characterized. It was observed that uniform temperature profiles along the antenna length were achieved with a length of wire of 99 mm +/- 2 mm. The effective heating length (length of the antenna that exhibits > 50% of the maximum temperature rise) was comparable to the antenna length. The radial penetration depth of 50% of the antenna surface temperature for the optimum 20 mm antenna was 2.5 mm from the antenna outer surface.

Barrett Esophagus↗
PubMed2001

Biogeography and ecological setting of Indian Ocean hydrothermal vents.

Within the endemic invertebrate faunas of hydrothermal vents, five biogeographic provinces are recognized. Invertebrates at two Indian Ocean vent fields (Kairei and Edmond) belong to a sixth province, despite ecological settings and invertebrate-bacterial symbioses similar to those of both western Pacific and Atlantic vents. Most organisms found at these Indian Ocean vent fields have evolutionary affinities with western Pacific vent faunas, but a shrimp that ecologically dominates Indian Ocean vents closely resembles its Mid-Atlantic counterpart. These findings contribute to a global assessment of the biogeography of chemosynthetic faunas and indicate that the Indian Ocean vent community follows asymmetric assembly rules biased toward Pacific evolutionary alliances.

Animals↗
PubMed2000

Communication between general and manipulative practitioners: a survey.

A survey of general practitioners (GPs) in the south of England was undertaken to determine their understanding and communication needs in referring patients to practitioners of manipulation. Eighty-six out of 309 GPs replied to a postal questionnaire (28% response). The results suggest that, while routine communication is important for improving understanding, GPs appear to have a preference for disciplines of which they have personal experience. The majority of responders favoured receiving a report on one side of A5 paper when the patient completes treatment. This should contain the nature of treatment and advice given and an indication of its outcome. Those who desired an initial report wanted it to contain a summary of the nature of the problem, a brief history, a summary of relevant findings from the examination, any investigations and a prognosis. Many GPs commented that they were more comfortable in referring to physiotherapists because they felt they had a better understanding of the treatment involved. Furthermore, chiropractic and osteopathic terminologies were reported to be confusing more often than physiotherapy terminology. Bearing in mind the potential bias in responses due to its geographical limitations and low response rate, this study provides useful indicators for manipulative and GPs who wish to work more closely together.

Adult↗
PubMed1998

Severe sepsis in the emergency department and its association with a complicated clinical course.

OBJECTIVE: Infection severity as determined by clinical criteria has been recently classified and studied in hospitalized inpatients. The objective of the study was to use modified criteria to determine the clinical course associated with three levels of infection severity in infected patients admitted from the ED. METHODS: This was a retrospective cohort study involving all patients 18 years of age and older admitted through the ED of an urban teaching hospital during a four-month period whose primary reason for requiring hospitalization was an infection that was recognized in the ED. ED records were reviewed for criteria used to classify patients by three levels of infection severity: no systemic inflammatory response syndrome, sepsis, and severe sepsis (SS). The relationships between these classifications as well as certain clinical characteristics and any complicated clinical course as measured by death and/or admission to an intensive care unit (ICU), and/or prolonged hospitalization, were analyzed. RESULTS: Of 408 patients entered into the study, 138 (33.8%) fulfilled the criteria of SS in the ED. Patients with SS in the ED had a mortality of only 4.3%, though with an increased risk of dying compared with that of the other groups combined [relative risk (RR) = 11.64, 95% confidence interval (CI) = 1.43 to 96.53], an increased risk of ICU stay (RR = 7.65, 95% CI = 4.08 to 14.36), and an increased risk of prolonged hospitalization (RR = 1.99, 95% CI = 1.38 to 2.88). Although age over 60 years and several comorbid conditions also were identified by univariate analysis as risk factors, multivariate analysis revealed that only SS and diabetes mellitus (DM) were independent predictors of a complicated course. In the authors' institution, the positive predictive value (PPV) of SS for complicated clinical course was 0.48 and the negative predictive value (NPV) of no SS for no complicated course was 0.77. The PPV of [SS + DM] was 0.83, and the NPV of [SS, DM, or both] was also 0.83. CONCLUSION: Although the strongest correlate of a complicated clinical course identified in the ED is SS as defined by the study criteria, its specificity and PPV are low. The mortality of ED patients with SS is much lower than the mortality rates reported for inpatients with SS. SS as defined by the study criteria is too sensitive and therefore lacks utility in the ED setting.

Adult↗
PubMed1997

Quantitating fetomaternal hemorrhages of D+ red cells using an FITC-conjugated IgG monoclonal anti-D by flow cytometry: a case report.

Several methods for quantitating fetomaternal hemorrhages (FMHs) have been described; these include the Kleihauer-Betke and red cell rosetting tests, and flow cytometry that uses an indirect antiglobulin technique, employing either FITC-conjugated IgG/unlabeled anti-D or streptavidin conjugates with biotinylated anti-D to enumerate D+ red cells in maternal blood. We have used a recently described directly conjugated FITC anti-D for direct flow cytometric (direct FC) quantitation of FMH in a patient who presented with a large fetal bleed (approx. 80 mL) as determined using the Kleihauer method. We compared the efficacy of the direct FC technique to the rosetting and Kleihauer tests in estimating the quantity of Rh immunoglobulin (RhIg) to be administered to the mother to suppress Rh alloimmunization. Both the Kleihauer and the direct FC gave precise estimates of 80 mL for the size of bleed, whereas the rosetting test failed to be as precise. The former tests predicted that a 10,000 iu dose (2,000 microg) of RhIg would be adequate; the lack of alloanti-D in a maternal follow-up sample obtained 9 months after delivery supported this prediction and underlined the reliability of the direct FC method as an alternative to the Kleihauer method for quantitating large FMHs.

Journal Article↗
PubMed1996

Physiological responses to repeated endotoxin challenge are selectively affected by recombinant bovine somatotropin administration to calves.

The study determined 1) whether the pretreatment of calves with recombinant bovine somatotropin (bST, sometribove) would alter the change in packed cell volume (PCV), rectal temperature (RT), and the plasma concentrations of Ca2+, Fe2+, glucose (G), urea N (PUN), nonesterified free fatty acids (NEFA), albumin (ALB), and blood cell populations after endotoxin challenge (EC) and 2) whether the natural development of physiologic tolerance to repeated EC was affected by bST. Twelve steer beef calves were assigned to either control (-bST) or +bST treatment in equal numbers. Calves were injected intramuscularly with either HCO3(-)-buffered saline or bST (0.1 mg/kg) daily for 5 d. On Day 6, the first EC was administered (Escherichia coli, 055:B5, 0.2 microgram/kg, intravenous bolus in pyrogen-free saline). Saline or bST injections were continued from Day 7 up to the repeat of EC on Day 11. RT and PCV were measured hourly through 12 and 6 hr, respectively. Jugular blood was obtained at 0, +1, 2, 3, 4, 6, 8, 12, and 24 hr relative to each EC. bST had no effect on the increase in RT, the hyperglycemic phase of the G response, the biphasic change in Fe2+, or increases in NEFA and PUN. PCV increased after each EC only in -bST. The mean decrease in G during the hypoglycemic phase was less in +bST. Hypocalcemic responses were significantly less in +bST. ALB concentrations decreased after each challenge; the response was unaffected by bST. CD2+, CD4+, and CD8+ T-lymphocyte populations were unaffected by bST and EC. Overall, the magnitude of change in all plasma variables was less after the second EC compared with the first, either in terms of magnitude or duration. The data suggest that the treatment of calves with bST diminishes the magnitude of hypoglycemic, hypocalcemic, and PCV changes after EC and does not compromise fever response, changes in blood cell populations, or tolerance to repeated EC.

Animals↗
PubMed1996

Evaluation of various sets of acoustic cues for the perception of prevocalic stop consonants. I. Perception experiment.

The purpose of the study presented in this paper and the accompanying paper [Smits et al., J. Acoust. Soc. Am. 100, 3865-3881 (1996)] is to evaluate whether detailed or gross time-frequency structures are more relevant for the perception of place of articulation of prevocalic stop consonants. To this end, first a perception experiment is carried out with "burst-spliced" stop-vowel utterances, containing the Dutch stops /b,d,p,t/ and /k/. From the utterances burst-only, burstless, and cross-spliced stimuli were created and presented to listeners. The results of the experiment show that the relative importance of burst and transitions for the perception of place of articulation to a great extent depends on place and voicing of the stop consonant and on the vowel context. Velar bursts are generally more effective in cueing place of articulation than other bursts. There is no significant difference in the effectiveness of /p/, /t/, and /k/ transitions, while /b/ transitions are more effective than /d/ transitions. The release burst dominates the perception of place of articulation in front-vowel contexts, while the formant transitions are generally dominant in nonfront vowel contexts. The bursts of unvoiced stops are perceptually more important than the bursts of voiced stops.

Humans↗
PubMed1996

Evaluation of various sets of acoustic cues for the perception of prevocalic stop consonants. II. Modeling and evaluation.

The purpose of the study presented in this paper and the accompanying paper [Smits et al., J. Acoust. Soc. Am. 100, 3852-3864 (1996)] is to evaluate whether detailed or gross time-frequency structures are more relevant for the perception of prevocalic stop consonants. To this end, first a perception experiment was carried out with "burst-spliced" stop-vowel utterances. This experiment is described in the accompanying paper. The present paper describes the second part of the investigation, i.e., the simulation of the behavior of the listeners in the perception experiment. First, a number of detailed and gross cues are measured on the stimuli. Next, these cues are mapped onto the observed perceptual data using a formal model of human classification behavior. The results show that in all cases the detailed cues, such as formant transitions, give a better account of the perceptual data than the gross cues, such as the global spectral tilt and its initial change. The best-performing models are interpreted in terms of the acoustic boundaries which are associated with the perceived linguistic contrast. These boundaries are highly interpretable linear functions of five or six acoustic cues, which give a quantitative description of the often-discussed "trade-off" relation between the various cues for perception of place of articulation in stop consonants.

Humans↗
PubMed1992

The job-finding module: training skills for seeking competitive community employment.

The opportunity to return to work is often the culmination of extensive and collaborative efforts by clients, psychiatrists, and allied mental health and rehabilitation practitioners. Successful vocational placement and tenure is a victory not only for each individual client but also for the comprehensive set of services and supports established to foster this self-determination. Much as a chain is only as strong as its links, successful job placement must be viewed as but one link in a comprehensive rehabilitation program. Our research in competitive community employment placement over the past decade has resulted in the development of the Job Finding Module, as our contribution to one link of this evolving chain of necessary treatment and rehabilitation services for the seriously mentally ill.

Aspirations, Psychological↗
PubMed1992

Correlations between psychiatric disabilities and vocational outcome.

Eighty-nine subjects were recruited from inpatient and community psychiatric treatment programs in the Los Angeles area to participate in the Brentwood Job Finding Club. They were trained in job-seeking skills and were given logistical support during their job search. Thirty-six percent either obtained a job or entered a job training program. Persons with good work histories, good job interviewing skills, and nonpsychotic diagnoses were more likely to find employment. Persons with psychotic diagnoses and poor work histories and those receiving Supplemental Security Income were the least successful.

Activities of Daily Living↗
PubMed1989

A trial of the calcium antagonist felodipine in hypertensive type 2 diabetic patients.

Although calcium antagonists may impair insulin release in vitro, clinical studies have produced conflicting results. Felodipine is a highly selective dihydropyridine calcium antagonist effective in the treatment of hypertension. The efficacy of felodipine was assessed in a double-blind randomized placebo cross-over study of 21 Type 2 diabetic patients with primary hypertension, 13 men and 8 women, with an age of 61 (range 46-73) years. Thirteen were controlled on oral hypoglycaemic therapy and 8 on diet alone. Mean (SD) blood pressure (mmHg) was 176(20)/102(8) after a 2-4 week placebo run-in period, 169(21)/101(8) during the subsequent placebo period compared with 151(15)/88(9) after 4 weeks felodipine therapy (p less than 0.001). Nineteen patients required 5 mg twice daily and 2 patients 10 mg twice daily to achieve a target diastolic pressure of 95 mmHg. Side-effects seen with felodipine included ankle oedema, facial flushing, headache, and dizziness. During oral glucose tolerance tests performed after the felodipine and placebo phases, mean (SD) fasting blood glucose was 9.5(3.1) and 9.0(3.0) mmol l-1, respectively (NS), and the 90 min (peak) blood glucose was 19.1(4.8) and 18.1(4.8) mmol l-1, respectively (NS). Glycosylated haemoglobin and fructosamine concentrations likewise showed no significant changes.

Apolipoproteins↗
PubMed1988

Discitis after discography.

A series of nine patients with post-discography discitis were evaluated to help delineate the clinical course. The most consistent sign was the marked exacerbation of neck or back pain. This then was followed by an elevated sedimentation rate at an average of 20 days, followed by a positive bone scan at an average of 33 days. Of note is that seven patients initially had negative bone scans at an average of 18 days. Five out of nine patients had changes on plain roentgenograms between 14 and 51 days after discography. Magnetic resonance imaging was performed in six patients; two of these patients were scanned twice. Three scans were negative and five were positive (2 patients initially had negative scans that later became positive). The course of lumbar discitis ranged from 8 to 11 weeks, and cervical discitis from 6 to 7 weeks, with the latter usually resulting in spontaneous fusion.

Adult↗
PubMed1986

Acoustic simulation experiments with preprocessed speech for an 8-channel cochlear implant.

A speech processor for simulation of preprocessed speech in cochlear implantation has been developed. An acoustic simulation of spectrally reduced speech was presented to 169 normally hearing subjects. Several perceptual tests with 9 different filter conditions were carried out. The intelligibility of sentences and the discrimination of phonemes in nonsense syllables were measured. It was established that even within one test session, an important learning effect occurred.

Cochlear Implants↗
PubMed1983

Consequences of spatial sampling by a human photoreceptor mosaic.

The short wavelength color mechanism in the human visual system can distinguish gratings from uniform fields of the same average radiance at spatial frequencies that are twice as high as the highest at which it can resolve bars in the grating. This discrimination above the resolution limit is associated with a splotchy or mottled appearance of the grating similar to two-dimensional noise. The most plausible explanation for the mottled pattern is that it is a moiré pattern produced by aliasing (spatial undersampling) by an irregular and sparse mosaic of short wavelength cones.

Color Perception↗