Pressure-preset ventilation. Part 2: Mechanics and safety.
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Biomedical subjects
Publications and source records attributed to M Jones.
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OBJECTIVE: To estimate the incidence of work disability among adults with asthma and to evaluate a clinically based illness severity score as a predictor of such disability. DESIGN: Baseline and follow-up telephone interviews and medical record review. SETTING: University-based outpatient pulmonary specialty practice. PATIENTS: Fifty-six patients interviewed at baseline; 42 reinterviewed 2 years later. MEASUREMENTS: Work disability ascertained by interview report and defined as change in job duties, reduction in pay, or change in job or employment status attributed to asthma. Severity of asthma score derived from medical records and based on respiratory symptom frequency, asthma history, and prescribed medications. Pulmonary function by routine testing. Logistic regression analysis of the 5-year incidence of work disability on severity score and forced expiratory volume in 1 s (FEV1). RESULTS: The 5-year work disability cumulative incidence was 19 percent for change in duties, 17 percent for reduction in pay, 20 percent for change in job or work status, and 36 percent for any of these measures. The median asthma score was 10 (range, 2 to 26). The mean FEV1 as a percent predicted (FEV1 percent) was 88 +/- 25 percent. Score and FEV1 percent were statistically correlated (r = -0.6, p < 0.0001). Severity of asthma score statistically predicted each measure of work disability (p < 0.01). Addition of FEV1 percent added little additional explanatory power to the logistic regression model (maximum chi 2 = 1.3, p > 0.2). CONCLUSIONS: Work disability is common among adults with asthma. A severity of asthma score based on clinical variables is statistically correlated with lung function but appears to be a stronger predictor of disability than airflow measured at one point in time.
Patients with non-cardiac chest pain (NCCP) (n = 387) and cardiac chest pain (CCP) (n = 93) were compared with community controls (n = 81), using a symptom questionnaire that assessed the presence of irritable bowel syndrome (IBS), functional dyspepsia, and oesophageal dysfunction and chest pain characteristics. A significantly (p < 0.05) increased prevalence of symptoms compatible with IBS occurred in NCCP patients when compared with those with CCP and with controls. Dysphagia was more frequent in both those with non-cardiac and cardiac chest pain than in controls; this was not apparent, however, when patients with concomitant IBS were excluded. The presence of oesophageal or gastrointestinal symptoms did not enable discrimination with regard to the chest pain characteristics. We conclude that unselected referred patients with documented NCCP are more likely to have IBS and that the presence of oesophageal symptoms such as dysphagia may merely reflect the spectrum of the 'irritable gut'.
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Intercellular adhesion molecule-3 (ICAM-3), the third receptor for lymphocyte function-associated antigen molecule-1 and a new member of the immunoglobulin superfamily has been recently characterized using specific monoclonal antibodies. In the present study, we show immunocytochemically that ICAM-3 is present on T and B cells in the mantle zones and on a subpopulation of follicular center cells in reactive lymph nodes and only occasionally in endothelium. In 52 cases of Hodgkin's disease, ICAM-3, although present on the majority of the reactive lymphoid cells, was absent from the Reed-Sternberg cells and their variants. However, in 28 cases (54%), there was prominent endothelial staining in small vessels. Similar findings were noted in 16 out of 49 cases (33%) of non-Hodgkin's lymphomas. This finding suggests that analogous to ICAM-1 and ICAM-2, ICAM-3 expression can be induced on endothelial cells in lymphoid neoplasms, probably by an as yet unidentified cytokine-mediated mechanism.
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X-linked hypohidrotic ectodermal dysplasia (EDA) has been localized to the Xq12-q13.1 region. A panel of genomic DNA samples from 80 unrelated males with EDA has been screened for deletions at seven genetic loci within the Xq12-13 region. A single individual was identified with a deletion at the DXS732 locus by hybridization with the mouse genomic probe pcos169E/4. This highly conserved DNA probe is from locus DXCrc169, which is tightly linked to the Ta locus, the putative mouse homologue of EDA. The proband had the classical phenotype of EDA, with no other phenotypic abnormalities, and a normal cytogenetic analysis. A human genomic DNA clone, homologous to pcos169E/4, was isolated from a human X-chromosome cosmid library. On hybridization with the cosmid, the proband was found to be only partially deleted at the DXS732 locus, with a unique junctional fragment identified in the proband and in three of his maternal relatives. This is the first determination of carrier status for EDA in females, by direct mutation analysis. Failure to detect deletion of the other loci tested in the proband suggests that the DXS732 locus is the closest known locus to the EDA gene. Since the DXS732 locus contains a highly conserved sequence, it must be considered to be a candidate locus for the EDA gene itself.
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Left ventricular function in mitral regurgitation has typically been studied in models that either sever the chordae tendineae or create a ventriculoatrial shunt. These methods may have adverse effects on left ventricular function independent of the regurgitant lesion. An animal model of chronic mitral regurgitation was therefore developed that both preserves annuloventricular continuity and avoids the use of external shunts. A circular 0.16 to 0.24 mm/kg defect was created in the anterior mitral valve leaflet of weanling sheep under direct vision with the aid of cardiopulmonary bypass. Six animals were studied preoperatively and immediately postoperatively (acute regurgitation group), and 20 animals were studied 8.1 +/- 0.2 (mean +/- one standard deviation) months postoperatively (chronic regurgitation group). Animals with chronic mitral regurgitation were compared with an age- and weight-matched control group that was not operated on (n = 7). Volumetric data and ejection fraction were derived from digitalized cineangiographic images. Maximal elastance was calculated from pressure-volume loops obtained from the simultaneous recording of left ventricular pressure by micromanometer-tipped left ventricular catheters, and volumes were obtained from digitalized images of epicardial echocardiographic recordings. Mitral valve perforation resulted in 3+ to 4+ mitral regurgitation and a calculated regurgitant fraction of 37% +/- 7% (mean +/- one standard deviation). Acute mitral regurgitation was associated with an increase in left ventricular end-diastolic volume from 110 +/- 17 to 121 +/- 23 ml (p < or = 0.05) and no change in end-systolic volume. These changes were associated with an increase in fractional shortening, from 29% +/- 11% to 40% +/- 10% (p < or = 0.05), and an increase in velocity of circumferential shortening, from 1.5 +/- 0.7 to 2.9 +/- 0.7 circ/sec (p < or = 0.05). However, there was no change in maximal elastance, a load-independent index of left ventricular function. Conversely, animals with chronic mitral regurgitation exhibited an elevated end-diastolic volume (202 +/- 32 versus 145 +/- 34, p < or = 0.05), an elevated end-systolic volume (104 +/- 17 versus 63 +/- 20 ml, p < or = 0.05), and a reduced ejection fraction (48% +/- 6% versus 57% +/- 9%, p < or = 0.05) compared with controls.(ABSTRACT TRUNCATED AT 400 WORDS)
The authors report the results of a 3-year (August 1984-May 1987) prospective study of intensive surveillance for nursing home-associated infections in 666 patients in a 300-bed nursing home in San Diego, California. Ninety-three percent (666 of 714) of the eligible subjects enrolled; 75% were women. The mean age of the subjects was 81.6 years. Lengths of stay ranged from 1 day to 1,025 days, with a mean of 166 days; the cumulative length of stay for all subjects was 110,746 days (303 years). Operational definitions that were heavily dependent on evaluation of clinical signs and symptoms were used by nurse practitioners in weekly or biweekly assessments of all patients to identify infections. The overall incidence of nursing home-associated infection was 7.1 infections/1,000 patient-days. Many of the infections would not have been recognized by persons less skilled than nurse practitioners. Among the 788 nursing home-associated infections identified, 362 (47%) were in the respiratory tract (286 lower respiratory and 76 upper respiratory); 200 (25%) were associated with skin and subcutaneous and mucous membranes; 140 (18%) were symptomatic urinary tract infections; 13 (2%) were bacteremia; and 73 (9%) were other infections.
An enhanced luminescence assay was developed to confirm the presence of HBsAg in weakly reactive sera. The test proved reliable in differentiating between truly reactive and falsely reactive samples.
Epithelioid hemangioendothelioma is the prototype of a group of vascular tumors characterized by epithelioid or histiocytoid endothelial cells. Epithelioid hemangioendothelioma of bone is a rare lesion that constitutes fewer than 1% of primary malignant skeletal neoplasms. We describe two cases that illustrate the spectrum of radiographic features seen with this neoplasm, and also present its appearance on magnetic resonance imaging.
A disease-oriented approach to the discovery of novel platinum anticancer drugs has been established through the setting up of parallel human ovarian-carcinoma cell lines and xenografts. The correlation between in vitro and in vivo antitumour activity was determined for four reference platinum agents (cisplatin, carboplatin, iproplatin and tetraplatin) in eight companion lines. Two methods of assessing antitumour effect were used in vitro (tritiated thymidine incorporation and sulforhodamine B staining) and three were applied in vivo [28-day treated/control (T/C) ratio, growth delay and specific growth delay]. In vitro, large differences in cytotoxicity across the cell lines were observed for each drug. This was also reflected in the xenografts for cisplatin and carboplatin and, to a lesser extent, for iproplatin. A correlation analysis of in vitro vs in vivo data revealed a high, statistically significant positive correlation for cisplatin and a strong positive correlation for carboplatin. However, for the two platinum(IV) drugs, the correlation was less good. In particular, tetraplatin was markedly less active in vivo (showing a general lack of activity against all of the tumour lines) than its in vitro potency against the cell lines predicted, resulting in poor correlation coefficients. These human tumour panels may be valuable for the elucidation of both cellular/molecular and corresponding in vivo pharmacological mechanisms of platinum drug resistance. Moreover, the HX/62 and SKOV-3 tumour lines, which exhibit a level of intrinsic resistance to the four reference agents both in vitro and in vivo (and which were derived from patients who had not received prior platinum therapy), represent particularly useful evaluation models for the discovery of novel broad-spectrum platinum drugs.
The aim of the study was to further elucidate the pathophysiology of irritable bowel syndrome and its subgroups by examining and comparing alterations in small bowel motility, specifically phase II and phase III components of the migrating motor complex. Prolonged recordings of interdigestive small bowel motility were obtained during both diurnal and nocturnal periods in 20 patients with irritable bowel syndrome--10 with predominant constipation and 10 with predominant diarrhea--and in 10 healthy subjects. Diurnal amplitude (mean +/- SD) of phase III activity fronts was lower (P less than 0.05) in constipation-predominant patients (16.3 +/- 3.1 mm Hg) than in diarrhea-predominant patients (20.2 +/- 3.1) or controls (20.9 +/- 2.7). Similar findings were observed nocturnally. Phase III cycle length was also significantly prolonged diurnally in constipation-predominant patients when compared to the other groups. In the diarrhea-predominant group repetitive and rapidly propagated bursts of contractions were observed in eight patients, and this pattern occupied a significantly greater proportion of phase II motor activity than in controls. These alterations in phase II and in phase III components of the migrating motor complex suggest that both local (enteric) and more central mechanisms may operate to produce intestinal dysmotility in the irritable bowel syndrome and that these mechanisms differ according to the predominant alteration of bowel habit.
The aetiological importance of stressful life events and psychological characteristics was assessed amongst 280 appendicectomy patients of whom 80% were classified with 'acutely inflamed' (organic) appendicitis and 20% with 'non-inflamed' (non-organic) appendicitis. Patients were compared with a community comparison group. Specific characteristics of life stressors, namely severe goal frustration for organic patients and severe threat for non-organic patients, were the best predictors of patient outcome. Whilst psychological characteristics were not useful in discriminating between patients, depression in particular, was clearly associated with both conditions, with 38% of non-organic and 28% of organic patients with depression scores in the clinical range. As the patient's clinical depression status failed to modify the effect of the life stress predictors, it was concluded that life stress played an important role in the development of the patients GI symptoms, irrespective of their clinical depression status.