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Biomedical subjects

M Stevens

Publications and source records attributed to M Stevens.

At least 109 records · Page 6Linked to original sources
PubMed1995

Management of frontal sinus fractures.

Frontal sinus fractures have been reported in 2 to 12 percent of all cranial fractures and, according to one study, in 8 percent of all facial fractures. Although immediate frontal bone reconstruction is not universally accepted, it is rapidly becoming the standard of care in treating cranial facial fractures, even in the face of gross contamination. This article presents a historical overview of fracture management, a review of the relevant anatomy, and a discussion of appropriate management principles. Three case studies are presented to demonstrate appropriate techniques for the management of frontal sinus fractures.

Adipose Tissue↗
PubMed1994

Family stressors in traumatic brain injury: a two-year follow-up.

A review of the literature suggests that psychosocial disability in traumatic brain-injured (TBI) individuals and distress in families continues long after the initial injury. In this study the relationship of family stress to a number of factors was studied longitudinally. Caregivers of 51 TBI inpatients were interviewed at rehabilitation admission and by phone at 6, 12, and 24 months postinjury. Caregivers' most common complaints about their relatives were a lack of involvement in leisure activities, fatigue, slowness, and forgetfulness. Increasingly severe temper outbursts, anxiety, and self-centeredness were reported over time. Aggressiveness was reported by caregivers as moderate or severe in 31% of cases by 2 years postinjury. Of all complaints, only reports of inappropriate social behavior decreased over time. Despite caregivers' increasing complaints about their relatives, there were no trends toward greater self-reported stress over time. At the 2-year assessment, stress was significantly higher for caregivers of those with an at risk psychosocial history, and for those without sufficient funds for services. Caregivers reporting financial strain increased 22% from rehabilitation admission. Forty-seven percent of caregivers had altered or given up their jobs at 1 year postinjury, and 33% at 2 years postinjury. Although self-perceived measurements of stress did not increase over time, caregivers reported notable increases in medication use and substance use, and decreases in employment and financial status over the 2-year time period. When spouse and parent caregiver responses were compared, spouses reported a consistently greater number of behavioral problems, which increased in severity over time. Those behaviors associated with mood disturbances predominated.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1994

Effect of allergen avoidance in infancy on allergic manifestations at age two years.

BACKGROUND: One hundred twenty children, identified before birth as being at high risk for atopy, were prenatally assigned to prophylactic or control groups. METHODS: The infants in the prophylactic group either received breast milk from mothers on an exclusion diet or an extensively hydrolyzed formula. Their bedrooms and living rooms were treated repeatedly with an acaricide, and they used polyvinyl-covered mattresses with vented head areas. The infants in the control group were fed conventionally, and no environmental control was recommended. RESULTS: A significant advantage, first demonstrated at 1 year of age, persists for children in the prophylactic group. They have less of any allergy or eczema, but the reduced prevalence of asthma is no longer significant. Only three children in the prophylactic group had positive skin prick test results compared with 16 in the control group, suggesting a significant reduction in sensitization. CONCLUSION: A dual approach to allergen avoidance, focusing on foods and aeroallergens, appears to be beneficial in selected high-risk infants. Avoidance of potent allergens in early life increases the threshold for sensitization in these high-risk infants. Whether sensitization has been avoided or merely deferred has yet to be proved.

Aging↗
PubMed1994

Pre-emptive analgesia: comparison of preoperative with postoperative caudal block on postoperative pain in children.

We have compared in 25 children the effect of preoperative with postoperative caudal block on pain after circumcision in a double-blind, randomized study. After induction of anaesthesia, patients were allocated randomly to receive a caudal block either before (n = 14) or immediately after (n = 11) surgery. Postoperative pain was rated on a paediatric pain scale. If pain occurred, children received paracetamol in a dose related to body weight. Using the Mann-Whitney U test (significance < or = 0.05) there was no significant difference in cumulative postoperative analgesic requirements within the first 48 h and in times to first analgesic administration between the groups. Cumulative pain score, assessed every 30 min for the first 8 h after operation, was significantly lower for those patients who received caudal anaesthesia after operation. Thus we could not demonstrate any advantage in performing caudal block before compared with after surgery.

Acetaminophen↗
PubMed1994

Evaluation of Biolog system for identification of some gram-negative bacteria of clinical importance.

The Biolog system (Biolog, Inc., Hayward, Calif.) was evaluated for the identification of 55 gram-negative taxa (789 strains) likely to be encountered commonly in clinical laboratories. The Biolog system performed best with oxidase-positive fermenters and biochemically active nonfermenters and had the most problems with unreactive nonfermenters. It gave significantly better results when the MicroPlates were read manually rather than when they were read by the automated reader. Plates read manually gave the following performances: oxidase-positive fermenters, five taxa, 64 strains, 92% correct, 3% not identified, and 5% incorrect; biochemically active nonfermenters, eight taxa, 122 strains, 88% correct, 6% not identified, and 6% incorrect; members of the family Enterobacteriaceae, 35 taxa, 511 strains, 77% correct, 8% not identified, and 15% incorrect; unreactive nonfermenters, seven taxa, 92 strains, 38% correct, 24% not identified, and 38% incorrect. We found the system easy to use, but while for 39 of 55 of the taxa an identification rate of > 70% was achieved, problems were encountered, particularly with identification of capsulated strains of some Enterobacter and Klebsiella taxa, as well as the least biochemically active Moraxella and Neisseria strains.

Bacterial Proteins↗
PubMed1994

Evaluation of two BBL Crystal systems for identification of some clinically important gram-negative bacteria.

The BBL Crystal system (Becton Dickinson Microbiology Systems, Cockeysville, Md.) is a miniaturized bacterial identification method employing modified conventional and chromogenic substrates. Two products are currently available, the Rapid Stool/Enteric ID Kit and the Enteric/Nonfermenter ID Kit, each comprising thirty tests. We report an evaluation of both systems (using database version 1.1 for both) in the identification of 51 gram-negative taxa likely to be encountered commonly in the clinical laboratory. In all, 266 strains were tested in the Enteric/Nonfermenter ID Kit, and these represented 36 taxa of the family Enterobacteriaceae (188 strains), 5 oxidase-positive fermentative taxa (26 strains), and 10 nonfermentative taxa (52 strains). The majority of these same strains (203 of 266) were also tested in the Rapid Stool/Enteric ID Kit. The Enteric/Nonfermenter ID Kit performed as follows: Enterobacteriaceae, 93% correct, 6% not identified, and 1% incorrect; oxidase-positive fermenters, 88, 12, and 0%, respectively; and nonfermenters, 100% correct, although several only to the genus or group level. The Rapid Stool/Enteric ID Kit gave the following results: Enterobacteriaceae, 91% correct, 7% not identified, and 2% incorrect; oxidase-positive fermenters, 80, 13, and 7%, respectively (but results were based on only 15 strains); and nonfermenters, 100% correct (but results were based on only 11 strains). We found the systems extremely easy and rapid to use, and for the Enteric/Nonfermenter ID Kit an identification rate of 100% in 40 of 51 taxa was achieved, with corresponding figures of 29 of 39 taxa for the Rapid Stool/Enteric ID Kit.

Bacteriological Techniques↗
PubMed1994

Unexplained unilateral vision loss during centrifugation.

Vision loss during a centrifuge run is an expected occurrence given the G-profile, physical fitness of the subject, expected visual endpoint [central light loss (CLL) or peripheral light loss (PLL)] of the experimental protocol, and the cyclic nature of the anti-G straining maneuver (AGSM). During a relatively low level G exposure, a subject experienced a unilateral loss of vision that did not resolve spontaneously upon removal of the G load. An extensive medical workup did not reveal any medical explanation for the vision loss.

Adult↗
PubMed1994

Factors influencing aeromedical decision-making: operational versus research environments.

The aeromedical research and operational flying communities have at least one common goal; ensuring the optimum combination of mission performance and safety for the aircrew. This is a continual challenge as aerospace technology leaps ahead while the human factor remains relatively constant. However, several issues interfere with the smooth interaction between these communities: 1) perceptions that the research and operational communities have towards human subjects and pilots respectively; 2) the legal and ethical considerations involved in exposing individuals to risk; and 3) the ever-present personality dynamics involved in any decision-making process (e.g., returning individuals to a centrifuge panel or flying duty after a medically disqualifying incident). All of these factors influence decisions made in both communities, and how they interact with each other. It is a dynamic process that varies between countries, individual services (e.g., Navy vs Air Force), and even between different geographical locations within the same service.

Aerospace Medicine↗
PubMed1993

Human T cell lines and clones respond to IL-9.

The activity of IL-9 on human T cells was investigated. Human T cell lines and clones, derived from PBMC by stimulation with PHA, IL-2, and irradiated allogeneic PBMC, were found to express a strong IL-9R message at the RNA level and to proliferate in the presence of IL-9, irrespectively of their CD4+ or CD8+ phenotype. Moreover, tumor-specific CTL clones also responded to IL-9. Contrasting with other T cell growth factors, such as IL-2, IL-4, or IL-7, IL-9 did not induce the proliferation of freshly isolated T cells. However, a significant proliferative response to IL-9 could be observed after a 10-day activation of PBMC with PHA, IL-2, and feeders. Taken together, our results indicate 1) that the activity of IL-9 on human T cells is wider than initially anticipated on the basis of the data obtained so far with murine cells; and 2) that proliferative responses to IL-9 require previous activation.

Cell Line↗
PubMed1993

Effective multi-agent chemotherapy for advanced abdominal lymphoma and FAB L3 leukemia of childhood.

Between June 1981 and May 1988, 51 children with diffuse undifferentiated, advanced (Murphy Stage III and IV) intra-abdominal non-Hodgkin's lymphoma were treated on an intensive multi-drug chemotherapy protocol without irradiation to the primary tumour. Therapy was completed for Stage III disease at one year, but Stage IV patients continued with a further year of therapy until January 1986, when it was reduced to one year. Central nervous system (CNS) prophylaxis consisted of eight doses of intrathecal MTX for all children, and 24 Gy cranial irradiation for Stage IV patients only. There were 42 patients with Stage III disease (III A n = 29 and III B n = 13) and nine patients with Stage IV disease, of whom eight had extensive bone marrow and extramedullary disease (FAB L3 ALL). No patient had CNS disease at presentation. Forty-eight of 51 children (94%) achieved a complete remission. Two children died during remission induction therapy and eleven children relapsed, mostly within eight months of diagnosis. All patients have completed therapy. Failure free survival is 76% for Stage III and 67% for Stage IV patients, with a median followup of 90 and 64 months, respectively. Subdividing Stage III patients into Stage III A and III B did not show significantly different survival (P = 0.9), but the number of patients in Stage III B is small. These results compare favourably with the most effective published protocols, and toxicity has been manageable.

Abdominal Neoplasms↗
PubMed1993

Altered lipid packing identifies apoptotic thymocytes.

To test whether apoptotic thymocytes can be identified by altered packing of lipids in their plasma membranes, thymocytes were isolated from mice injected with hydrocortisone and stained with merocyanine 540 (MC540), a fluorescent probe sensitive to lipid packing. At 9-10 h after injection, a subpopulation of H2-Klo cells with increased MC540 staining was clearly discernable. When DNA degradation was assessed by staining fixed cells with propidium iodide (PI), the fraction of cells with increased MC540 staining corresponded to the fraction with reduced PI staining. In addition, enriching for the former by fluorescence-activated cell sorting enriched for the latter. These results indicate that living apoptotic thymocytes can be identified and separated on the basis of altered lipid packing and increased staining with MC540.

Animals↗
PubMed1993

The effect of genetic and environmental factors on the prevalence of allergic disorders at the age of two years.

The effect of genetic and environmental factors on the prevalence of allergic disorders in early childhood was determined in a prospective follow-up study. Information was available on 1174 children at the age of 2 years. Two-hundred and seventy-five were considered to have an allergic disorder. The prevalence varied from 3.2% for rhinitis to 10.9% for asthma. At 2 years 60 children reacted positively on skin-prick test (SPT). Multivariate logistic regression analysis was used to obtain adjusted odds ratios (95% confidence interval) for each factor. For asthma, positive family history, male sex, low birth-weight, maternal smoking and season of birth were significant risk factors. For eczema, positive family history was the only significant risk factor. For rhinitis, lower socio-economic group and autumn birth were significant. Male sex and low birth-weight were significant for skin test positivity. Positive family history and low birth-weight were significant risk factors for any allergy. Low birth-weight was also a significant risk for skin test reactivity to house dust mite. Genetic and environmental factors have a profound effect on the development of allergic disorders in the first two years of life.

Child, Preschool↗
PubMed1993

Comparison of Signal and Bactec NR-660 blood culture systems.

The Signal blood culture system was compared with the Bactec NR-660. A total of 1617 blood culture sets yielded 143 (8.8%) significant isolates; 113 (79.0%) were from positive bottles in both the Bactec and Signal systems. Twelve organisms (8.4%) were detected and isolated from the Signal system only and another 18 (12.6%) from the Bactec system only. Of these 18, five were Signal-positive but the organism was not recovered and four organisms were isolated from negative Signal bottles on terminal subculture. The time taken to detection for each system was similar; the Signal system detected 68% and the Bactec 63% of significant positives within 24 h. At 48 h Bactec detected 91% and the Signal 85%. A significantly-reduced number of bottles which gave a positive signal but were negative by microscopical and cultural methods was found, compared with previous reports. The 1 h incubation period prior to the insertion of the Signal growth indicator device was considered to be the cause of this reduction in the proportion of false positives. Fifty-five percent (42/77) of the Bactec false positives were due to delta growth value. This is when there is an increase in the growth index of > or = 15 without the positive threshold level of 30 being attained. This occurred in the anaerobic bottle on day 2 with 42 bottles. Another 40% (31/77) of the false positives had a growth value between the positive threshold of 30 and a value of 35. Eighty (4.9%) of Bactec and 65 (4.0%) of Signal sets yielded clinically non-significant isolates.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Erythromycin induces supranormal gall bladder contraction in diabetic autonomic neuropathy.

Gall bladder motor function is impaired in some patients with diabetes. It has been suggested that the abnormalities of gall bladder motility are confined to those patients with autonomic neuropathy. Erythromycin, a motilin receptor agonist, causes gall bladder contraction in both normal subjects and patients with gall stones with impaired gall bladder emptying. The effect of erythromycin on gall bladder motility in seven patients with diabetes with an autonomic neuropathy, six patients with diabetes without autonomic neuropathy, and 17 normal subjects was studied using ultrasound. There was no significant difference in gall bladder fasting volume between the three groups, but the patients with diabetes with autonomic neuropathy had impaired postprandial gall bladder emptying compared with normal subjects (percentage emptied (SEM) 40 (10.3)% v 64 (2.8)%, p < 0.01) and those with autonomic neuropathy (48 (7.7)%, NS). Erythromycin produced a dramatic reduction in gall bladder fasting volume in patients with diabetes with an autonomic neuropathy, compared with either normal subjects or patients with diabetes without autonomic neuropathy (percentage reduction 62 (4.6)% in patients with autonomic neuropathy, v 37 (17.6)% in those without autonomic neuropathy, and 26 (7.3)% in the normal subjects, (p < 0.02) and returned gall bladder emptying to normal in all patients with impaired emptying. The pronounced effect of erythromycin in diabetic autonomic neuropathy suggests denervation supersensitivity and that the action of erythromycin on the gall bladder is neurally modulated.

Adult↗
PubMed1993

Evaluation of Questor urine screening system for bacteriuria and pyuria.

AIMS: To evaluate the Questor automated bacteriuria and pyuria screening system; to compare its performance with that of a reference method; and to assess its usefulness in a routine clinical laboratory. METHODS: The Questor urine screening system was compared with a comprehensive regimen to detect urinary tract infection, using pour-plate viable counts to determine the numbers of bacteria present in urine samples, a wide range of other cultural methods, microscopic findings and clinical information. RESULTS: The optimal performance in detecting significant growths was a sensitivity of 93%, a specificity of 74%, a positive predictive value of 43% and a negative predictive value of 98%. The list price per test is 0.17 pounds and the capital cost of the system is 39,950 pounds. Questor can test 50 samples an hour and can be operated by one member of the laboratory staff, who is not required to make interpretative judgments--for example, a medical laboratory assistant. CONCLUSIONS: The sensitivity and specificity of the Questor was better than that obtained from other screening systems using the same protocol. The system was easy to use and is a useful addition to the methods available for screening for bacteriuria.

Bacteriuria↗
PubMed1992

The role of hypotension in septic encephalopathy following surgical procedures.

To study the risk factors for septic encephalopathy, we reviewed a consecutive series of 84 patients with septic syndrome and multiple-organ failure. Septic encephalopathy developed in 14 of these patients. Univariate analysis revealed that severe hypotension was significantly associated with the development of septic encephalopathy. In stepwise multiple logistic regression analysis, no other variable made a significant contribution in the presence of severe cardiovascular failure. Septic encephalopathy may be related to ischemic damage rather than to metabolic causes.

Adult↗