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Biomedical subjects

T Johnson

Publications and source records attributed to T Johnson.

At least 109 records · Page 6Linked to original sources
PubMed1998

Long-term postoperative cognitive dysfunction in the elderly ISPOCD1 study. ISPOCD investigators. International Study of Post-Operative Cognitive Dysfunction.

BACKGROUND: Long-term postoperative cognitive dysfunction may occur in the elderly. Age may be a risk factor and hypoxaemia and arterial hypotension causative factors. We investigated these hypotheses in an international multicentre study. METHODS: 1218 patients aged at least 60 years completed neuropsychological tests before and 1 week and 3 months after major non-cardiac surgery. We measured oxygen saturation by continuous pulse oximetry before surgery and throughout the day of and the first 3 nights after surgery. We recorded blood pressure every 3 min by oscillometry during the operation and every 15-30 min for the rest of that day and night. We identified postoperative cognitive dysfunction with neuropsychological tests compared with controls recruited from the UK (n=176) and the same countries as study centres (n=145). FINDINGS: Postoperative cognitive dysfunction was present in 266 (25.8% [95% CI 23.1-28.5]) of patients 1 week after surgery and in 94 (9.9% [8.1-12.0]) 3 months after surgery, compared with 3.4% and 2.8%, respectively, of UK controls (p<0.0001 and p=0.0037, respectively). Increasing age and duration of anaesthesia, little education, a second operation, postoperative infections, and respiratory complications were risk factors for early postoperative cognitive dysfunction, but only age was a risk factor for late postoperative cognitive dysfunction. Hypoxaemia and hypotension were not significant risk factors at any time. INTERPRETATION: Our findings have implications for studies of the causes of cognitive decline and, in clinical practice, for the information given to patients before surgery.

Abdomen↗
PubMed1998

Randomised controlled trial of two models of care for discharged psychiatric patients.

OBJECTIVE: To compare the clinical outcome and costs of care of psychiatric patients allocated to community multidisciplinary teams or to hospital based care programmes after discharge from inpatient care. DESIGN: Randomised controlled trial. SETTING: Inner London (Paddington and North Kensington) and outer London (Brent) psychiatric services. SUBJECTS: 155 patients with severe mental illness with a previous admission within the past 2 years. MAIN OUTCOME MEASURES: Ratings of clinical psychopathology, depression, anxiety, and social functioning; comprehensive costs of health care. RESULTS: Clinical outcomes were available for 133 patients and cost data for 144 patients after 1 year. The clinical outcomes of the two models of care were essentially similar, but admission to hospital was more likely in the hospital based care group and the costs of health care were 14% greater per patient than in the community group. This difference, however, was dwarfed by a twofold difference in the costs of care in the outer London services compared with those in inner London. This was explained largely by greater inpatient care for outer London patients (58 median bed days v 18 for inner London patients), more of which was provided by extracontractual referrals to other psychiatric hospitals as Brent had only 0.28/1000 beds available for acute adult patients compared with 0.82/1000 in Paddington and North Kensington over the period of the study. CONCLUSION: Aftercare by community teams for psychiatric patients with severe mental illness has a similar outcome to hospital based aftercare but with fewer admissions to hospital. When psychiatric bed requirements are insufficient for a population, however, neither form of aftercare is effective as greater use of hospital beds elsewhere swamps any advantage of community care programmes, with disintegration and discontinuity of psychiatric services leading to escalating costs.

Adolescent↗
PubMed1998

Intraorbital implants after enucleation and their complications: a 10-year review.

BACKGROUND: Many different types of orbital implants have been used after enucleation. Associated complications such as infection, exposure, extrusion, and ptosis have been reported. OBJECTIVE: To describe 342 consecutive patients who underwent enucleation with intraorbital implant placement at the Bascom Palmer Eye Institute, University of Miami School of Medicine, Miami, Fla, during the past 10.5 years and their complications. METHODS: Medical records of orbital implantation after enucleation performed by 3 surgeons (T.G.M., D.T., and T.J.) were reviewed retrospectively. Demographic data, ocular diagnosis, previous ophthalmic surgery, implant characteristics, and postoperative complications were described in all patients, with a minimum of 2 months' follow-up, using a standardized format. RESULTS: Eleven complications were observed in 7 patients. Four patients had exposure of the implant, and 1 of these patients developed associated infection. Three patients developed pyogenic granulomas, 1 patient developed ptosis requiring surgical intervention, 1 patient had long-term orbital discomfort, and 1 patient developed an inclusion cyst. CONCLUSION: Complications after enucleation with orbital implant placement are minimal and are observed with both porous and acrylic orbital implants.

Acrylic Resins↗
PubMed1998

An automatic device for the assessment of cardiovascular autonomic function.

Autonomic neuropathy is a common complication of diabetes mellitus and is associated with significant morbidity and possibly an increase in mortality. Despite this, however, autonomic dysfunction is not usually sought in the routine assessment of diabetic patients. We report the development and testing of a small, portable and reliable device that allows the routine testing of cardiac autonomic function in the outpatient setting with minimal inconvenience to the patient. This should facilitate the accurate assessment both of patients with symptoms suggestive of autonomic dysfunction and of autonomic function in research.

Arrhythmias, Cardiac↗
PubMed1998

Prediction of outcome in neurotic disorder: a 5-year prospective study.

BACKGROUND: There have been no previous studies of the outcome of different neurotic disorders in which a prospective group with original randomization to treatment have been followed up over a long period. Such studies are important in identifying the factors associated with good and poor outcome. METHODS: A 5-year follow-up assessment was made of a cohort of 210 psychiatric out-patients seen in general practice psychiatric clinics with a DSM-III diagnosis of generalized anxiety disorder (71), panic disorder (74) or dysthymic disorder (65) and randomized to drug treatment, cognitive and behaviour therapy, and self-help. A total of 182 of the patients (87%) were assessed after 5 years by examination of hospital and GP records using a standardized procedure and outcome determined with a four-point outcome scale. RESULTS: One hundred and seven (60%) of the patients had a favourable outcome but the remainder continued to be handicapped either intermittently or continuously throughout the 5-year period. Analysis of the value of initial data in predicting outcome using polychotomous step-wise logistic regression revealed that five variables were significant predictors of poor prognosis: older age; recurrent episodes; the presence of personality disorder at entry; general neurotic syndrome at entry; and symptom severity after 10 weeks. The initial DSM diagnosis and original treatment given, together with ten other variables, were of no predictive value. CONCLUSIONS: The long-term outcome of neurotic disorder is better predicted by age, personality and recency of onset than by other clinical variables with the exception of initial response to treatment.

Adult↗
PubMed1998

Cytotoxic geranyl stilbenes from Macaranga schweinfurthii.

Three novel geranyl stilbenes, schweinfurthins A, B, and C (1, 2, and 3), were isolated from the Cameroonian plant Macaranga schweinfurthii (Euphorbiaceae) and their structures determined by NMR and mass spectral methods. The cytotoxicity profile of the schweinfurthins tested in the NCI 60-cell screen was similar to that of the stelletins and cephalostatins, suggesting that these structurally diverse natural products may share similar mechanisms of cytotoxicity.

Antineoplastic Agents, Phytogenic↗
PubMed1998

The role of head injury in cognitive functioning, emotional adjustment and criminal behaviour.

In two investigations, 50% of non-violent convicted felons, who avoided incarceration by participating in a day reporting programme, reported a prior history of head injury and current problems in cognitive and emotional functioning. Only 5% of a college sample in the first investigation and 15% of a community sample in the second investigation reported prior head injury. In a third investigation, 83% of felons who had reported a history of head injury also reported a date for their head injury that preceded the date of their first encounter with law enforcement. Some participants reported no trouble with the law until after experiencing a head injury that occurred in their late thirties. Considering the research reported here and elsewhere in the literature, it appears that many serious crimes follow a head injury. One implication of the findings reported here is that many crimes might not occur if people with head injury were given prompt and comprehensive treatment after the injury.

Adaptation, Psychological↗
PubMed1998

Clinical trials of antibacterial agents: a practical guide to design and analysis. Statisticians in the Pharmaceutical Industry Working Party.

Guidelines on the conduct of clinical trials of antibacterial agents produced by the US Food and Drug Administration, the British Society for Antimicrobial Chemotherapy, the Infectious Diseases Society of America and a European Working Party have been reviewed. Although very informative, these guidelines provide limited practical guidance on the design and statistical aspects of phase III studies of antimicrobial agents. This paper describes the differences between antibacterial trials and clinical studies in other therapeutic areas with regard to subjective endpoints, dual clinical and bacteriological endpoints, frequent protocol violations and difficulty of using placebo controls. The importance of a detailed protocol and planned analysis strategy is emphasized. The choice of comparator agents, practical issues with the blinding of trial materials and the documentation of patients excluded from study entry are discussed. The use of different patient groups and different endpoints in analyses are described. The principles of equivalence and their application to trials of antibacterial agents are discussed, together with an approach to calculating sample size. A variety of statistical analyses of results are compared for different situations indicating some of the problems that can arise. Different methods of presentation of study data are included with emphasis on regulatory submissions rather than scientific publications. Some graphical presentations are recommended and issues regarding data across different studies are discussed.

Anti-Infective Agents↗
PubMed1998

Amphetamines in hair by enzyme-linked immunosorbent assay.

Human hair was collected from the occipital crown region of the head from several subjects; these hair samples were presumptively positive for amphetamines by a previously evaluated immunoassay. Hair was washed briefly with methanol to remove external contamination, then extracted with hot methanol for 2 h to recover the drugs. The extracts were evaporated to dryness, reconstituted in buffer, and analyzed using a new enzyme-linked immunosorbent assay (ELISA) technique adapted for the detection of amphetamines in hair. Gas chromatography-mass spectrometry was used as the reference technique. Cross-reactivity of several related compounds was evaluated by equating the inverse of the ligand concentration at 50% antibody binding to the affinity constant for each compound. The ratio of a compound's affinity constant to that for d-methamphetamine was used to derive percent crossreactivity. These experiments yielded values of 30.8% for d-amphetamine, 7.4% for I-methamphetamine, 4.3% for phentermine, 2.9% for I-amphetamine, and <1% for ephedrine, methylenedioxyamphetamine, and methylenedioxymethamphetamine. Cross-reactivity of unrelated compounds was found to be non-existent. The optimum cutoff concentration was determined by receiver operating characteristic curve analysis to be 300 pg/mg and the observed limit of detection was 60 pg/mg. Intra-assay precision at 300 pg/mg was 3.3% (coefficient of variation, CV), and the interassay CV was 10.5%. The sensitivity and specificity of the method were 83% and 92%, respectively.

Amphetamine-Related Disorders↗
PubMed1998

Care tracker: a new approach to nursing care in ambulatory settings.

The shift from inpatient to ambulatory settings and the increasingly large and diverse numbers of ambulatory clients require reengineering and cost-effective approaches to managing ambulatory care. With data on 921 encounters in 12 ambulatory clinics, we developed CARE TRACKER, an instrument to describe nursing encounters by type, intervention, staff, time, and cost. Distinguishing nursing from medical interventions is an appreciable improvement over the traditional practice of bundling nursing as part of overhead costs. If managers can track the care delivered, they can better calculate staffing requirements, staff mix, inservice needs, and the costs of their existing and projected services.

Ambulatory Care↗
PubMed1998

Quantitative structure-activity relationship studies of a series of sulfa drugs as inhibitors of Pneumocystis carinii dihydropteroate synthetase.

Sulfone and sulfanilamide sulfa drugs have been shown to inhibit dihydropteroate synthetase (DHPS) isolated from Pneumocystis carinii. In order to develop a pharmacophoric model for this inhibition, quantitative structure-activity relationships (QSAR) for sulfa drugs active against DHPS have been studied. Accurate 50% inhibitory concentrations were collected for 44 analogs, and other parameters, such as partition coefficients and molar refractivity, were calculated. Conventional multiple regression analysis of these data did not provide acceptable QSAR. However, three-dimensional QSAR provided by comparative molecular field analysis did give excellent results. Upon removal of poorly correlated analogs, a data set of 36 analogs, all having a common NHSO2 group, provided a cross-validated r2 value of 0.699 and conventional r2 value of 0.964. The resulting pharmacophore model should be useful for understanding and predicting the binding of DHPS by new sulfa drugs.

Dihydropteroate Synthase↗
PubMed1998

von Willebrand factor does not influence atherogenesis in arteries subjected to altered shear stress.

The role of von Willebrand factor (vWF) in arterial neointimal formation that develops in arteries with altered shear stress was investigated using normal, heterozygous, and homozygous von Willebrand disease pigs (ie, vWD, or lacking vWF) that were fed normal pig chow. Shear stress was applied to carotid and femoral arteries with a Goldblatt clamp for 14 days, producing a > or = 80% stenosis. Neointimal lesion size was measured by computer-assisted morphometry. Expression of proliferative cell nuclear antigen (PCNA) by neointimial and medial cells was used as a relative index of proliferative activity. For shear-stressed arteries, there was no significant difference in the number of smooth muscle cell layers in the lesion, lesion size, and percent of PCNA-positive neointimal or medial cells among normal, heterozygous, and homozygous vWD pigs (P> or =.1, ANOVA). Lesions in pigs that expressed vWF (normals and heterozygotes) contained large amounts of vWF in the neointima, whereas lesions in vWD pigs had no detectable vWF. Moreover, no foam cells were detected in the lesions. Thus, the absence of vWF apparently does not alter the size of lesions in shear-stressed arteries in vWD pigs or the number of neointimal or medial cells expressing PCNA. Mechanism(s) involved with shear-induced modulation of smooth muscle cell proliferation, then, can operate independently of vWF in normolipemic pigs.

Animals↗
PubMed1998

Clinical trials in psychiatry: background and statistical perspective.

There have been many hundreds of studies which have examined the efficacy of different forms of treatment of psychiatric disorders over the past 40 years. This paper presents some background to these studies for statisticians, illustrating and discussing some of the difficult problems which arise in this specialty of medicine. It also demonstrates a major requirement for statisticians to influence both the design and presentation of clinical trials and provides some suggestions about how this may be done.

Clinical Trials as Topic↗
PubMed1998

Prospective evaluation of 2-[18F]-2-deoxy-D-glucose positron emission tomography in staging of regional lymph nodes in patients with cutaneous malignant melanoma.

PURPOSE: To assess prospectively the accuracy of 2-[l8F]-2-deoxy-D-glucose positron emission tomography (FDG-PET) for predicting regional node involvement in cutaneous malignant melanoma (CMM). PATIENTS AND METHODS: Twenty-three patients with CMM (primary lesions > 1.5 mm thick) scheduled for lymph node dissection (LND) were preoperatively studied with FDG-PET. Thirteen patients underwent therapeutic LND of 14 node basins, while nine patients had elective LND of 10 node basins. Medical problems precluded surgery in one patient. Two observers unaware of the clinical node status-apart from whether a recent surgical scar was present-read attenuation-corrected reconstructed transverse images acquired between 50 and 60 minutes after injection. Intensity of FDG uptake was scored as 0 to 3 + on a semiquantitative four-point scale: 0, no uptake; 1 +, faint; 2 +, moderate; and 3 +, intense uptake. A node group was considered positive on FDG-PET if it contained at least one focus of FDG uptake of > or = 2+ intensity. Histopathologic examination of the 24 dissected node groups served as a reference. RESULTS: Considering regional node basins, PET imaging demonstrated 11 true-positive (TP), 10 true-negative (TN), two false-negative (FN), and one false-positive (FP) result, for an overall accuracy of 88%. Histopathologic from one FN case showed seven malignant cells in a marginal node sinus. The FP was due to reactive changes postbiopsy. In one patient, clinically involved lymph nodes were correctly categorized TN by PET. At least four additional 2 + foci seen outside the dissected regions on PET may represent metastases and are being monitored. CONCLUSION: FDG-PET accurately predicted regional node status in 88% of CMM cases. The failure to detect micrometastatic disease may be due to the limitations of the imaging equipment and technique used here.

Female↗
PubMed1998

Is central nervous system prophylaxis necessary in ocular adnexal lymphoma?

PURPOSE: To examine the frequency of metastasis to the eye and central nervous system (CNS) from ocular adnexal lymphomas and to evaluate whether CNS prophylaxis is appropriate for these tumors. PATIENTS AND METHODS: Seventy-one patients with biopsy-confirmed ocular adnexal lymphomas were evaluated between 1989 and 1995. The lymphomas were subclassified histopathologically according to the new Revised European-American Lymphoma (REAL) criteria. Molecular genetic analysis of tumor cell DNA was done by Southern blot. Patients had a complete ophthalmologic evaluation and metastatic work-up and were then routinely followed up by an ophthalmologist and a medical oncologist. RESULTS: The 34 men and 37 women studied had a median age of 67 years (23 to 92). Ocular adnexal lymphomas were situated in the orbit in 54 patients, in the conjunctiva in 14 patients, and in the eyelid in 3 patients. Bilateral involvement occurred in 11 patients. The most common histologic diagnoses were (54 patients, 76%) extra-nodal marginal zone lymphomas and small lymphocytic lymphomas in 10 patients (14%). Molecular genetic analysis performed in all patients confirmed a monoclonal B-cell population in 55 patients (77%), including a single rearrangement of the immunoglobulin heavy chain gene in 14 patients, and more than two rearrangements in 41 patients. No patients had isolated T-cell gene rearrangements. Localized ocular adnexal lymphoma was diagnosed in 43 patients (61%), 17 patients (24%) were found to have concurrent extraocular lymphoma on metastatic work-up and 11 patients (15%) had a previous diagnosis of systemic lymphoma before the onset of their ocular tumor. The median duration of follow-up was 20 months. Overall, 32 patients (45%) had tumors, which remained localized to the orbit adnexa. Eleven patients (15%) relapsed, but none had eye or central nervous system involvement nor required CNS-directed therapy. Although eight patients died, only two died as a direct result of systemic lymphoma. No patient received CNS prophylaxis with either intrathecal chemotherapy and/or radiation therapy. CONCLUSION: Ocular adnexal lymphomas are rare non-Hodgkin's B-cell lymphomas. Metastatic involvement of the eye or central nervous system is rare and CNS prophylaxis with radiotherapy or chemotherapy is unnecessary.

Adult↗