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Biomedical subjects

L Evans

Publications and source records attributed to L Evans.

At least 55 records · Page 3Linked to original sources
PubMed1997

Estimation of the clinically diagnosed proportion of sleep apnea syndrome in middle-aged men and women.

The proportion of sleep apnea syndrome (SAS) in the general adult population that goes undiagnosed was estimated from a sample of 4,925 employed adults. Questionnaire data on doctor-diagnosed sleep apnea were followed up to ascertain the prevalence of diagnosed sleep apnea. In-laboratory polysomnography on a subset of 1,090 participants was used to estimate screen-detected sleep apnea. In this population, without obvious barriers to health care for sleep disorders, we estimate that 93% of women and 82% of men with moderate to severe SAS have not been clinically diagnosed. These findings provide a baseline for assessing health care resource needs for sleep apnea.

Adult↗
PubMed1997

Splenic micro-anatomical localization of small lymphocytic lymphoma/chronic lymphocytic leukemia using a novel combined silver nitrate and immunoperoxidase technique.

Small lymphocytic lymphoma/chronic lymphocytic leukemia (SLL/CLL) may be histologically difficult to differentiate from reactive lymphoid hyperplasia (RLH) in the spleen. Because routine hematoxylin and eosin (H&E) staining delineates splenic microanatomy poorly, we have developed a method that simultaneously stains reticulin fibers and B-lymphocytes. B3 or formalin-fixed, paraffin-embedded archival splenic tissue with diagnoses of SLL/CLL (11 cases), RLH (10 cases), and trauma (seven cases) were studied using a novel silver nitrate immunoperoxidase (SNIP) double-staining technique. Gordon and Sweet's reticulin stain was followed by immunoperoxidase staining for B-lineage marker CD20 (Dakopatts, Carpinteria, CA) using the avidin-biotin method. This allowed us to clearly localize B cells to Malpighian bodies, periarteriolar lymphoid sheaths, sinuses, or cords. Features identified by SNIP found only in SLL/CLL, but not in RLH or traumatized spleens, were trabecular infiltration (eight of 11 cases), subendothelial infiltration (seven of 11 cases), and prominent sinus involvement (seven of 11 cases). One or more of these features were seen in 10 of 11 cases of SLL/CLL. Other distinguishing features were the percentage area occupied by B-lymphocytes in each section (SLL/CLL = 74%; RLH = 46%; traumatized spleens = 36%); and mean spleen weight (SLL/CLL = 1,603 g; RLH = 287 g; traumatized spleens = 126 g). We have found the SNIP technique to be superior to traditional H&E staining in identifying B cells in the context of splenic microanatomy.

Adolescent↗
PubMed1997

Effects of a restraint reduction intervention and OBRA '87 regulations on psychoactive drug use in nursing homes.

OBJECTIVES: To describe the changes in psychoactive drug use in nursing homes after implementation of physical restraint reduction interventions and mandates of the Omnibus Budget Reconciliation Act of 1987 (OBRA '87). METHODS: A secondary analysis was conducted using data from a controlled clinical trial that took place in three nursing homes: a control home, one that received an educational intervention, and one that received an educational/consultation intervention. All three homes were influenced by the OBRA mandates. Complete pre- and 6 months' post-intervention data on use of psychoactive drugs and physical restraints were available for 446 resident subjects. Changes were first analyzed with the resident subjects as the unit of analysis and then using the nursing home ward (n = 16) as the unit of analysis. RESULTS: While physical restraint use declined in the home that received the educational/consultation intervention, neither neuroleptic nor benzodiazepine use increased in any of the homes after the interventions. The percentage of residents taking neuroleptics declined in the control home (18.6% to 11.3%, P = .014). Benzodiazepine use, which was more prevalent than described previously in the literature, declined in all three homes (P < .001). Of those residents whose physical restraints were discontinued, only 2% were started on neuroleptics. When the effect of OBRA mandates on appropriateness of neuroleptic use was examined, the percentage of residents on neuroleptics who lacked an OBRA-approved indication declined from 21.3% to 14.6% in the total sample, and from 39.9% to 8% in the control home. CONCLUSIONS: Interventions to reduce physical restraint did not lead to an increase in psychoactive drug use; further, reduction in both can occur simultaneously. OBRA mandates regarding psychoactive drug use were not uniformly effective, but appear, at minimum, to have increased awareness of the indications for neuroleptics.

Aged↗
PubMed1997

Activation of diacylglycerol in cultured endothelial cells exposed to cyclic strain.

Confluent bovine aortic endothelial cells (EC) were grown on flexible membranes and subjected to 10% average strain at 60 cycles/min for up to 500 s. A biphasic increase in diacylglycerol (DAG) occurred, with an initial transient peak at 10 s followed by sustained elevation to 500 s. The early peak corresponded to the transient formation of inositol 1,4,5-trisphosphate, demonstrating hydrolysis of L-alpha-phosphatidylinositol (PI) by PI-specific phospholipase C. To determine the origin of the sustained DAG phase, we incubated confluent bovine aortic EC with 1 microCi/ml [14C]myristate overnight and subjected them to cyclic strain. There was a decrease in phosphatidylcholine (PC) and a corresponding increase in DAG at 10 s and 250 s, suggesting PC hydrolysis with the generation of DAG at both an early (10 s) and a late (250 s) phase. [14C]phosphatidylethanol, a specific product of phospholipase D (PLD) in the presence of 1% ethanol, was measured in EC preincubated with [14C]myristate. Cyclic strain led to an immediate and sustained activation of PLD. Increased ethanol concentration led to a consistent decrease in DAG. Furthermore, when EC were pretreated with 1% ethanol, the strain-induced proliferative response was attenuated.

Animals↗
PubMed1997

The comorbidity of anxiety and depression.

OBJECTIVE: This study explored the effect of comorbid anxiety disorders in patients admitted to an inpatient specialist Mood Disorders Unit for the treatment of a primary major depressive episode. METHOD: Subjects were assessed on admission and discharge. DSM-III-R diagnoses for major depression and anxiety disorders were established using CIDI-Auto; comorbid anxiety disorders were coexistent in time with the major depression, with both conditions meeting diagnostic criteria at the time of assessment. Severity of illness was assessed using the Hamilton Depression/Melancholia Scale, the revised Hamilton Anxiety Scale and the revised Beck Depression Inventory. RESULTS: For the analysis, the study cohort was divided into three groups: depression alone (n = 33), one comorbid anxiety disorder (n = 15), and two or more comorbid anxiety disorders (n = 24). No particular anxiety disorder predominated. Interestingly, the presence or absence of comorbid anxiety with severe major depression made no significant difference to treatment choice or outcome results. Specifically, there was no significant difference between the three groups in the utilisation of electroconvulsive therapy and pharmacotherapy (including antidepressants, benzodiazepines and neuroleptics); all subjects improved significantly on both depression and anxiety ratings, and length of inpatient stay did not vary significantly between the three groups. CONCLUSIONS: The existence of comorbid anxiety disorders in those patients who presented for treatment of a primary major depressive episode did not significantly effect choice of treatment or treatment outcome, suggesting that there is a close interrelationship between the two conditions.

Adult↗
PubMed1996

Changes in adenine nucleotides during hemorrhagic shock and reperfusion.

Certain tissues are known to be susceptible to shock-induced damage: liver, small bowel mucosa, and small bowel wall. This study was done to assess the changes in adenine nucleotides induced by hemorrhagic shock. Male Sprague-Dawley rats (n = 21; 300-350 g) were anesthetized with sodium pentobarbital (50 mg/kg, ip) and mechanically ventilated. The external jugular vein and common carotid artery were cannulated. Laparotomy was done. Hemorrhagic shock was induced by withdrawing blood into a heparinized syringe until a mean arterial blood pressure of 40 mm Hg was obtained and was maintained for 30 min by continued withdrawals. Shed blood was then reinfused through the venous catheter. No additional fluid was administered. The animals were observed for another 60 min. Throughout the procedure, biopsies were taken of liver and small bowel. The small bowel biopsies were separated into mucosal and wall fractions. Nucleotides were extracted. ATP, ADP, AMP, adenosine, inosine, xanthine, and hypoxanthine were measured with gradient HPLC. Cellular ATP concentrations decreased significantly during shock (P < 0.05). Liver ATP dropped from 8.93 +/- 0.55 to 2.91 +/- 0.16 micromol/g dry tissue (mean +/- SEM) (33%), small bowel mucosal ATP from 9.40 +/- 1.04 to 3.26 +/- 0.21 (35%), and small bowel wall ATP from 5.47 +/- 0.36 to 2.74 +/- 0.18 (50%). The nucleotide response to shock in small bowel mucosa was closer to that of liver than to that of small bowel wall. After reperfusion, ATP levels were partially restored in liver, small bowel mucosa, and small bowel wall, but not to preshock values. All of the metabolites (adenosine, inosine, hypoxanthine, and xanthine) increased during shock (P < 0.05), and did not return to preshock levels after reperfusion. The abnormalities in ATP and its metabolites, and their persistence after reperfusion, suggest a possible mechanism for the production of postshock damage.

Adenine Nucleotides↗
PubMed1996

Antilock brakes and risk of front and rear impact in two-vehicle crashes.

While antilock brakes (ABS) have been convincingly demonstrated to enhance test track braking performance, their effect on crash risk in actual driving has been less clear. This research was conducted to seek clear associations between ABS and risk of involvement in one particular class of crashes, namely, two-vehicle crashes, particularly on wet roads. Police reported crashes in which a following vehicle strikes the rear of a lead vehicle are extracted from 1992 and 1993 calendar-year data for five states. The study uses seven General Motors passenger vehicles having ABS as standard equipment for 1992 models but not available for 1991. It is found that when driving on wet roads ABS reduces the risk of a vehicle crashing into a lead vehicle compared to its risk of being struck in the rear by (48 +/- 6)% (the error limits are one standard error). This large effect could arise from reduced risk of front impacts or increased risk of rear impacts. Using the assumption that side-impact crashes estimate exposure showed that, for wet roads, ABS reduces the risk of crashing into a lead vehicle by (32 +/- 8)%, but increases the risk of being struck in the rear by (30 +/- 14)%.

Accidents, Traffic↗
PubMed1996

Safety-belt effectiveness: the influence of crash severity and selective recruitment.

While theoretical considerations show that the effectiveness of occupant protection devices declines from 100% at very low crash severity to 0% at high severity, empirical details have been lacking. When overall in-use effectiveness is estimated by applying traditional methods to data sets that lack a measure of severity, large biases are introduced because non-wearing drivers are riskier drivers, an effect that has been called selective recruitment. These effects are investigated empirically using National Accident Sampling System (NASS) data in which crash severity is measured by delta-v, the estimated change in the speed of the car as a result of the crash. Supplemental results are obtained using published police-reported data containing a more easily obtained but less objective severity measure. Both data sets provide information on driver fatalities and injuries, thus allowing four comparisons of effectiveness estimates based only on total casualties with ones taking into account the different severities of crashes by belted and unbelted drivers. The data show consistently that the probability that a driver is belted declines as crash severity increases. Belt effectiveness estimates ignoring this effect are biased upwards by large amounts (for example, 60% compared to 40% for injuries using NASS data). Belts appear more effective at preventing fatalities than at preventing injuries. The results are consistent with a prior estimate, derived using a method unaffected by the biases discussed here, which found that, averaged over all crashes, safety belts reduce driver fatality risk by (42 +/- 4).

Accidents, Traffic↗
PubMed1996

The costs of managing lower limb-threatening ischaemia.

One hundred and fifty consecutive patients presenting with limb-threatening ischaemia were studied prospectively to determine treatment and rehabilitation costs in the first year. Limb salvage was attempted in 104 (69%) patients but failed in 13%. Mortality at 1 year was 27%. The cost of treatment, inpatient stay, occupational therapy, physiotherapy, convalescence, disablement services, home adaptations, home care, district nursing, transportation and outpatient visits were determined for each patient. The patients were classified according to their presentation and initial treatment into five groups (number of patients) whose median management costs (interquartile range) for 12 months were: Gp 1 (23 - Revascularisation for acute ischaemia = 3970 pounds (2984-5511) Gp 2 (29) - Angioplasty for critical ischaemia = 6611 pounds (3630-10,200) Gp 3 (52) - Reconstruction for critical ischaemia = 6766 pounds (4337-9677) Gp 4 (34) - Primary amputation = 10,162 pounds (7894-13,026) Gp 5 (12) - Primary bilateral amputations = 13,848 pounds (11,440-18,056) At 1 year, there was no significant difference in the cost of managing a patient with a critically ischaemic limb by angioplasty or surgical reconstruction. The cost of revascularisation for acute ischaemia was comparatively low because these patients required minimal rehabilitation. The median cost of managing a patient following amputation was almost twice that of successful limb salvage justifying an aggressive revascularisation policy. However, justification of such a policy on economic grounds requires salvage failure episode to be minimised as they increase costs considerably.

Absenteeism↗
PubMed1996

Physical restraint use and falls in nursing home residents.

OBJECTIVE: To examine the relationship between restraint use and falls while controlling for the effect of psychoactive drug use among nursing home residents, including subgroups of nursing home residents with high rates of restraint use and/or falls. DESIGN: Secondary analysis of data from a longitudinal clinical trial designed to reduce restraint use. SETTING: Three nursing homes. PARTICIPANTS: Subjects (n = 322) were either restrained (n = 119) or never restrained (n = 203) at each observation point during a 9.5-month data collection period that preceded the intervention phase of the clinical trial. MEASUREMENTS: We evaluated restraint status (independent variable) three times during the data collection period by direct observation over a 72-hour period. Incident reports documenting falls and fall-related injuries (dependent variables) were reviewed. Cognitive status was measured using the Folstein Mini-Mental State Exam and functional status (including ambulation status) by the Psychogeriatric Dependency Rating Scale. Psychoactive drug use profile was obtained through record review. MAIN RESULTS: Using multiple logistic regression, we compared the effect of restraint use on fall risk between a confused ambulatory subgroup and the remaining sample and found a significant difference in the odds ratio for falls and recurrent falls (P = .02; chi-square = 5.24, df = 1; P = .003, chi-square = 9.12, df = 1). In the confused ambulatory subgroup, restraint use was associated with increased falls (odds ratio: 1.65, 95% CI: 0.69, 3.98) as well as recurrent fall risk (odds ratio: 2.46, 95% CI: 1.03, 5.88). Increased falls and recurrent fall risk was not observed in the remaining sample (falls odds ratio: 0.49, 95% CI: 0.28, 0.87; recurrent falls odds ratio: 0.42, 95% CI: 0.20, 0.91). One subgroup, the nonconfused ambulatory residents, were never restrained; after removing this subgroup, the confused ambulatory continued to be associated, though not significantly, with a higher risk of falls and injuries. Only nonconfused nonambulatory restraints were associated with a lower risk of all three outcomes: falls (odds ratio: 0.28, 95% CI: 0.05, 1.58), recurrent falls (odds ratio: 0.48, 95% CI: 0.05, 4.72), and injurious falls (odds ratio:0.42, 95% CI: 0.04, 4.01); these results, however, were not statistically significant. There was no evidence that the effect of restraint use on fall risk depended upon the use of psychoactive drugs (chi square = 4.43; df = 2, P = .11). CONCLUSION: Restraints were not associated with a significantly lower risk of falls or injuries in subgroups of residents likely to be restrained. These findings support individualized assessment of fall risk rather than routine use of physical restraints for fall prevention. Researchers and clinicians should continue to focus efforts on developing a variety of approaches that reduce risk of falls and injuries and promote mobility rather than immobility.

Accidental Falls↗
PubMed1996

A multistep process of leukemogenesis in Moloney murine leukemia virus-infected mice that is modulated by retroviral pseudotyping and interference.

Mixed retroviral infections frequently exhibit pseudotyping, in which the genome of one virus is packaged in a virion containing SU proteins encoded by another virus. Infection of mice by Moloney murine leukemia virus (M-MuLV), which induces lymphocytic leukemia, results in a mixed viral infection composed of the inoculated ecotropic M-MuLV and polytropic MuLVs generated by recombination of M-MuLV with endogenous retroviral sequences. In this report, we describe pseudotyping which occurred among the polytropic and ecotropic MuLVs in M-MuLV-infected mice. Infectious center assays of polytropic MuLVs released from splenocytes or thymocytes of infected mice revealed that polytropic MuLVs were extensively pseudotyped within ecotropic virions. Late in the preleukemic stage, a dramatic change in the extent of pseudotyping occurred in thymuses. Starting at about 5 weeks, there was an abrupt increase in the number of thymocytes that released nonpseudotyped polytropic viruses. A parallel increase in thymocytes that released ecotropic M-MuLV packaged within polytropic virions was also observed. Analyses of the clonality of preleukemic thymuses and thymomas suggested that the change in pseudotyping characteristics was not the result of the emergence of tumor cells. Examination of mice infected with M-MuLV, Friend erythroleukemia virus, and a Friend erythroleukemia virus-M-MuLV chimeric virus suggested that the appearance of polytropic virions late in the preleukemic stage correlated with the induction of lymphocytic leukemia. We discuss different ways in which pseudotypic mixing may facilitate leukemogenesis, including a model in which the kinetics of thymic infection, modulated by pseudotyping and viral interference, facilitates a stepwise mechanism of leukemogenesis.

3T3 Cells↗
PubMed1996

The relationship between AIDS dementia complex and the presence of macrophage tropic and non-syncytium inducing isolates of human immunodeficiency virus type 1 in the cerebrospinal fluid.

We sought to determine the clinical significance of macrophage tropic and non-syncytium inducing isolates of human immunodeficiency virus type 1 (HIV-1) in the cerebrospinal fluid (CSF) of patients with and without AIDS dementia complex (ADC). HIV-1 was isolated from the CSF of 31 patients with and without ADC. The isolates were then characterised as to the degree of macrophage tropism by quantitation of p24 production and the presence of syncytium inducing (SI) or non-syncytium inducing (NSI) isolates by MT2 assay and SupT1 coculture. The degree of macrophage tropism varied according to the donor macrophage that was used except in strongly macrophage tropic isolates. Moderate and severe ADC (stage > or = 2) was associated with the presence of highly macrophage tropic isolates in the CSF (P = 0.01). The sensitivity and specificity values of a highly macrophage tropic isolate in the CSF for ADC stage > or = 2 were 82% and 66% respectively while the predictive value was 64%. Three of four asymptomatic patients with such highly macrophage tropic isolates in the CSF subsequently developed ADC after an average of 4 months. Twenty-eight isolates from the CSF and 23 from the blood were NSI regardless of the presence or absence of ADC. The predictive value of an SI isolate in the blood reflecting an SI isolate in the CSF was 37.5% while the predictive value of an NSI isolate in the blood reflecting an NSI in the CSF was 100%. These data suggest that host factors are essential in determining the degree of macrophage tropism in HIV-1 and that such tropism is important for the presence and possibly subsequent development of ADC. The CSF usually has NSI isolates regardless of the presence of ADC and irrespective of the presence of such isolates in the blood thereby suggesting that the CSF is behaving virologically as a separate compartment to the blood.

AIDS Dementia Complex↗
PubMed1995

Surgery for limb threatening ischaemia: a reappraisal of the costs and benefits.

OBJECTIVES: To study the quality of life of patients following surgery for critical limb is ischaemia. DESIGN: Part retrospective, part prospective open study. SETTING: Vascular unit of a University Hospital. MATERIALS: Seventy-nine consecutive patients, medium age 75 years (range 44 to 94), who presented with leg threatening ischaemia and who underwent successful revascularisation or a major amputation were studied. CHIEF OUTCOME MEASURES: Six separate quality of life measures were recorded at 6 months: pain, mobility, anxiety, depression, activities of daily living (Barthel) and lifestyle (Frenchay). MAIN RESULTS: The mortality of this group of patients after six months was 24%. Forty-seven patients were available for quality of life assessment six months after initial intervention. Overall, amputation was more costly than successful revascularisation and limb salvage. Limb salvage resulted in greater mobility (p < 0.001) and better performance in self-care (p < 0.001) and lifestyle (p = 0.006), but produced more anxiety and depression (p = 0.04) than major amputation. A subgroup of patients who had major amputation after a failed limb salvage operation consumed a disproportionate amount of resources and, although their mobility was typical of amputees, their self-care and lifestyle scores were similar to those who had successful limb salvage. OBSTRUCTIONS: Limb salvage is attempted in up to 22% of patients for whom primary amputation may provide more expeditious rehabilitation with minimal impairment of their lifestyle performance.

Activities of Daily Living↗