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Biomedical subjects

R Miller

Publications and source records attributed to R Miller.

At least 343 records · Page 19Linked to original sources
PubMed1996

Cortico-thalamic interplay and the security of operation of neural assemblies and temporal chains in the cerebral cortex.

Much evidence suggests that the mammalian thalamus is not merely a set of nuclei relaying signals to the cerebral cortex, but is engaged in two-way interplay with it. Three important features constrain ideas about the nature of this interplay: (i) thalamic projection neurones lack local axon collaterals; (ii) most corticothalamic projections have very long axonal conduction time; (iii) in the waking state the membrane potential of thalamic projections cells appears to be poised just beneath threshold for firing. It is proposed that corticothalamo-cortical pathways represent connections between different cortical loci which have higher security than the direct cortico-cortical route. Thus each thalamo-cortical projection neurone can have a singular and pivotal role in the activation of one or more cortical neural assemblies. The long delays of cortico-thalamic conduction suggest that the cortico-thalamo-cortical loop also plays a crucial role in the operation of time-structured neural assemblies ('synfire chains'; Abeles), by providing a high-security link from one active node of the chain to nodes activated at a later time in the sequence. It is predicted that, in the waking animal, thalamic projection cells should have a response selectivity to complex percepts and concepts, conferred on them by the cortical assemblies in whose activation they participate.

Afferent Pathways↗
PubMed1996

AIDS-associated vacuolar myelopathy and tumor necrosis factor-alpha (TNF alpha).

The spinal cords from 15 patients with AIDS-associated vacuolar myelopathy (VM), 4 AIDS patients without VM, and 5 HIV-seronegative controls, were studied with immunocytochemistry for TNF alpha. CSF and blood from HIV-seropositive patients with VM (n = 16), non-vacuolar myelopathies (n = 8), CNS infection but no clinical myelopathy (n = 31), no clinical or radiological evidence of CNS disease (n = 9), and from 7 HIV-seronegative controls with motor neurone disease were assayed for TNF alpha using an ELISA technique. TNF alpha was present on immunostaining in all the 15 cords with VM studied. The stained cells were macrophages, microglia and endothelial cells. The amount of immunostaining was higher in cords with VM compared with cords from HIV-seropositive patients without VM (p = 0.001). The distribution of staining corresponded to the areas of pathology but did not correlate with the severity of the VM. Immunostaining was also higher in the HIV-seropositive group compared to the HIV-seronegative controls (p = 0.001). There was no significant difference in the levels of TNF alpha in the CSF of patients with VM compared to any of the other groups studied. Blood levels of TNF alpha were lower in the HIV-seropositive controls without CNS disease and in the HIV-seronegative MND controls, than in patients with VM, non-vacuolar myelopathies, and CNS disease. CSF TNF alpha levels did not appear to be a reliable indicator of intramedullary levels. The findings support the hypothesis that TNF alpha may be relevant in the pathogenesis of vacuolar change in VM.

Acquired Immunodeficiency Syndrome↗
PubMed1996

Response in chronic schizophrenia correlated with chlorpromazine, 7-OH-chlorpromazine and chlorpromazine sulfoxide levels.

The relationship between chlorpromazine, six of its metabolites and therapeutic response in chronic schizophrenic patients was investigated in this study. Logistic regression revealed no correlation between therapeutic response and four metabolites viz. Nor1 chlorpromazine, Nor2 chlorpromazine, chlorpromazine-N-oxide and Nor2 chlorpromazine sulfoxide. A good correlation was seen between CPZ (P = 0.036), 7-hydroxychlorpromazine (P = 0.004), chlorpromazine sulfoxide (P = 0.002) and therapeutic response. Good therapeutic response was correlated to high levels of chlorpromazine and its 7-hydroxy metabolite while high levels of the sulfoxide metabolite appeared to have a negative effect on therapeutic response. Poor responders who had high levels of chlorpromazine also had high levels of the sulfoxide metabolite. This suggests that the difference in response may lie in the difference in the metabolism of the drug.

Adolescent↗
PubMed1996

Metabolic response to radiation therapy in patients with cancer.

The effect of radiation therapy on substrate metabolism was evaluated in five patients with head and neck or lung cancer. Stable isotope tracer methodology was used to determine urea, amino acid, glucose, and lipid kinetics during postabsorptive conditions before initiation, near the midpoint (after receiving 2,672 +/- 36 rads), and at completion (after receiving 6,072 +/- 307 rad) of a 6- to 8-week course of radiation therapy. Nutritional status was maintained throughout the treatment period by providing supplemental enteral feedings as needed. Postabsorptive plasma insulin, catecholamine, and amino acid concentrations did not change during the course of treatment. Before radiation therapy was initiated, values for the plasma rate of appearance (Ra) of urea (3.35 +/- 0.33 micromol x kg(-1) x min(-1)), alpha-ketoisocaproate ([alpha-KIC] 2.16 +/- 0.19 micromol x kg(-1) x min(-1)), phenylalanine (0.59 +/- 0.052 micromol x kg(-1) x min(-1)), and glucose (10.56 +/- 1.31 micromol x kg(-1) x min(-1)) were in the normal range. However, glycerol and palmitate Ra values (3.11 +/- 0.30 and 2.01 +/- 0.33 micromol x kg(-1) x min(-1), respectively) were 25% higher than values observed previously in normal subjects. Substrate flux did not change during radiation therapy, and measurements obtained during the midpoint and at completion of treatment were similar to initial values. These results demonstrate that large doses of radiation therapy, administered over 6 to 8 weeks to the upper body, do not cause significant metabolic stress.

Amino Acids↗
PubMed1996

Learning through outdoor activities as part of a P2000 mental health branch programme.

'Outdoor activity' training was introduced into a P2000 Mental Health Branch Programme as a means of developing a range of personal and interpersonal qualities and skills. In this article, the authors outline the process of setting up this venture, identify aspects of the curriculum relevant to outdoor activities, giving examples of some of the activities and make links to nursing practice. Finally, an evaluation of this project is offered which suggests positive outcomes as a result of these teaching and learning strategies.

Camping↗
PubMed1996

The odyssey of Orpheus: the evolution of solo singing.

Notated sacred solo song dates from 1,000 B.C. Early secular song exhibits modest vocal demands of chant-like character. Popular song and liturgical solo song share common origins. Western European secular song notation began in the early Medieval Age. Compositional writing for solo voice took a dramatic turn toward virtuosity about 1600. By the mid-17th century, the modern solo voice emerged. "Classical" solo vocal literature is not static but is constantly evolving, requiring skills far in excess of those of speech or of early solo song literature; this is equally the case with ethnomusicological and popular singing styles. Efficient use of the singing instrument is essential to the healthy accomplishment of all of these literatures.

Christianity↗
PubMed1996

Measuring healing in leg ulcers: practice considerations.

Clinical nursing practice requires reliable and valid methods of measuring healing in patients with leg ulcers. By comparing the reliability and validity of four methods of measuring leg ulcer healing, digital planimetry (computerized area measurement), the Kundin Wound Gauge (volume and area measurement), the Healing Scale (measuring perceptions of healing), and the Johnson Scale (measuring wound characteristics), with the standard technique of stereophotogrammetry, implications for nursing practice and research were identified. Stereophotogrammetry, defined as topographical mapping measuring volume and area, was found to be reliable and suitable for clinical trial evaluations and for monitoring healing in hospitals or clinics. In a sample of hospital and community patients with leg ulcers (n = 82), weekly clinical comparisons using digital planimetry and the Kundin Wound Gauge, both reliable methods, supported the suitability of these measures, for monitoring healing in any setting (r = .99; r = .98, respectively). The Healing and Johnson Scales did not show concurrent validity when compared with stereophotogrammetric methods and had limited reliability. This study provided three reliable and valid methods of measuring healing suitable for practice. Time intervals and endpoints for clinical trials and evaluating practice need to be considered in terms of instrument error rates and delayed healing in older people.

Aged↗
PubMed1996

Acquired immunodeficiency syndrome and ocular calcification.

We report the presence of peculiar nonbanded calcification of the cornea in three patients with acquired immunodeficiency syndrome, discovered on postmortem histological examination of the globes. In one patient, multiple calcium salt precipitates also affected other ocular and orbital structures. Calcium deposits were present in the corneal stroma but spared Bowman's layer, as is usually seen in primary and secondary corneal calcification. The calcified areas were positive to von Kossa, alizarin red, alcian blue, and colloidal iron stains. Electron probe analysis of the three cases showed the presence of calcium and phosphorus in a ratio characteristic for hydroxyapatite. No predisposing factors could be found. The possible role of associated alterations in the mucopolysaccharide content or composition in the calcified areas is unclear.

Acquired Immunodeficiency Syndrome↗
PubMed1996

Microsatellite instability in early onset and familial colorectal cancer.

Hereditary non-polyposis colorectal cancer syndrome (HNPCC) is often considered to be the most common form of inherited colorectal cancer, although its precise incidence is unknown. The clinical diagnosis of HNPCC relies on a combination of family history and young age of onset of colorectal cancer, but as many familial aggregations of colorectal cancer do not fulfil the strict diagnostic criteria, HNPCC might be underdiagnosed. The majority of HNPCC families have germline mutations in mismatch repair (MMR) genes, such as MSH2 or MLH1, so that HNPCC cancers characteristically exhibit DNA replication errors (RERs) at microsatellite loci. Although an RER positive phenotype in tumours can also result from somatic mutations in an MMR gene, the prevalence of RER + tumours should provide a maximum estimate of the incidence of germline MMR gene mutations in patients with early onset and familial colorectal cancer. We investigated colorectal cancers for RERs from (1) a population based study of 33 patients with colorectal cancer aged 45 years or less, (2) 65 kindreds with familial colorectal cancer which only partially fulfilled the criteria for the diagnosis of HNPCC, and (3) 18 cancers from 12 HNPCC kindreds. Seven of 33 patients (21%) with colorectal cancer aged 45 years or less had an RER + cancer, with only two of these having a clear family history of HNPCC. A greater proportion of RER + tumours (5/7) occurred proximal to the splenic flexure than RER - tumours (4/26; chi2 = 6.14, p < 0.025). RERs were detected in all 18 cancers from HNPCC patients but in only six of 65 non-HNPCC familial colorectal cancer kindreds (9%; chi2 = 52.2, p < 0.0005). These findings suggest that most cancers in patients diagnosed at 45 years of age or less and familial aggregations of colorectal cancer which do not fulfil HNPCC diagnostic criteria do not have germline mutations in MSH2 and MLH1. Hence population screening for germline mutations in these genes is unlikely to be an efficient strategy for identifying people at high risk of developing colorectal cancer.

Adult↗
PubMed1996

Crusted ("Norwegian") scabies in a specialist HIV unit: successful use of ivermectin and failure to prevent nosocomial transmission.

A nosocomial outbreak of scabies in a specialist inpatient HIV unit resulted from a patient admitted with crusted scabies. Treatment of his infestation with topical scabicides alone failed and he remained infectious for several weeks. His infestation was then eradicated with combined topical treatment and oral ivermectin. In total, 14 (88%) out of 19 ward staff became symptomatic, and 4 (21%) had evidence of scabies on potassium hydroxide examination of skin scrapings. The ward infection control policy was changed to distinguish patients with crusted scabies from those with ordinary scabies. A second patient with crusted scabies was treated with combined oral and topical therapy early in his admission and nursed with more stringent isolation procedures. No nosocomial transmission occurred and his infestation responded rapidly to treatment. Patients with crusted scabies require strict barrier nursing if nosocomial transmission is to be avoided. Ivermectin combined with topical scabicides may be a more efficacious treatment than topical scabicides alone in such patients.

Adult↗
PubMed1996

The haemolytic uraemic syndrome in patients with AIDS.

OBJECTIVE: Thrombotic microangiopathies have been increasingly recognised in HIV infection. The contribution of haemolytic uraemic syndrome (HUS) has not received as much emphasis as other members of the thrombotic microangiopathies. We describe the clinical features and prognosis of HUS in a group of patients with AIDS. SETTING: St Bartholomew's and The Middlesex Hospitals, London. PATIENTS: Five HIV seropositive individuals with clinical and histological features consistent with HUS. INTERVENTIONS: Blood transfusion, fresh frozen plasma, haemodialysis, renal biopsy, autopsy. CONCLUSIONS: HUS occurs in advanced HIV infection. Hypertension was a prominent clinical feature in HUS in this patient group. Measures to limit renovascular damage were unsuccessful and haemodialysis was usually needed to support renal function. The prognosis is poor, no patient achieved clinical remission and all died.

Acquired Immunodeficiency Syndrome↗
PubMed1996

Relationship of the Tufts Quantitative Neuromuscular Exam (TQNE) and the Sickness Impact Profile (SIP) in measuring progression of ALS. SSNJV/CNTF ALS Study Group.

The Tufts Quantitative Neuromuscular Exam (TQNE) is a standardized tool for measuring muscle strength and pulmonary function in patients with amyotrophic lateral sclerosis (ALS). We describe the relationship of TQNE scores to functional disability and health-related quality of life as measured by the Sickness Impact Profile (SIP) in 524 ALS patients. There was a significant relationship (p < 0.0001) between TQNE and SIP scores, both in cross section and over time. TQNE scores strongly relate to ALS patients' quality of life and ability to perform activities of daily living.

Activities of Daily Living↗
PubMed1996

Research needs for the risk assessment of health and environmental effects of endocrine disruptors: a report of the U.S. EPA-sponsored workshop.

The hypothesis has been put forward that humans and wildlife species adverse suffered adverse health effects after exposure to endocrine-disrupting chemicals. Reported adverse effects include declines in populations, increases in cancers, and reduced reproductive function. The U.S. Environmental Protection Agency sponsored a workshop in April 1995 to bring together interested parties in an effort to identify research gaps related to this hypothesis and to establish priorities for future research activities. Approximately 90 invited participants were organized into work groups developed around the principal reported health effects-carcinogenesis, reproductive toxicity, neurotoxicity, and immunotoxicity-as well as along the risk assessment paradigm-hazard identification, dose-response assessment, exposure assessment, and risk characterization. Attention focused on both ecological and human health effects. In general, group felt that the hypothesis warranted a concerted research effort to evaluate its validity and that research should focus primarily on effects on development of reproductive capability, on improved exposure assessment, and on the effects of mixtures. This report summarizes the discussions of the work groups and details the recommendations for additional research.

Animals↗
PubMed1996

One-stop shopping: the rest of the story.

The premise of home care one-stop shopping is that one company with an array of services will be more efficient, and therefore, cost-effective, for a managed care organization than several different companies providing services. As home care companies race to become one-stop shops, there are advantages and disadvantages to entering alliances, developing in-house expertise, or acquiring other companies. This article takes a realistic look at one-stop shopping and argues that it may not always be the best way to serve managed care organizations and their patients and should not be the only long-term solution for the home care industry.

Decision Making, Organizational↗