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Biomedical subjects

B Cooper

Publications and source records attributed to B Cooper.

At least 37 records · Page 2Linked to original sources
PubMed1994

Activation of mechanonociceptors by pro-inflammatory peptides melittin and PLAP peptide.

Studies were conducted to characterize the chemical reactivity of A and C fiber mechanical and mechanoheat nociceptors that innervate the goat palatal mucosa. In mechanical nociceptors, no significant chemical reactivity to either serotonin, bradykinin, prostaglandin E1, or prostaglandin E2 was observed, regardless of whether substances were injected singly or in spaced sequential combinations. Weak reactivity was observed in mechanoheat nociceptors. In contrast, both mechanical and mechanoheat nociceptors were activated by novel proinflammatory peptides. Nineteen of 30 mechanonociceptors and 12 of 13 mechanoheat nociceptors were activated by the insect venom peptide, melittin or its endogenous mammalian homologue PLAP (phospholipase A2 activating protein) peptide. Low threshold mechanoreceptors were never activated by melittin or PLAP peptide.

Animals↗
PubMed1994

Incidence and relative risk of dementia in an urban elderly population: findings of a prospective field study.

To ascertain the frequency and distribution of new cases of dementing illness in the elderly population of Mannheim (population 308,000), a survey sample of community residents of > 65 years of age was re-examined after an interval of 7-8 years, and a sample of elderly persons in long-stay care after 5-6 years. The estimated annual incidence rate for all forms of dementia, after correction for ageing of the samples, was 15.4 per 1000 persons aged > 65, made up of dementia of Alzheimer type (8.9 per 1000), vascular dementia (4.4 per 1000) and other forms (2.1 per 1000). Apart from the expected association with age > 65 years, the most powerful predictors of onset of a dementing illness were residence in long-stay care and the presence of minor cognitive deficits at the initial examination, each of which was associated with a highly significant increase in risk. In addition, a number of socio-demographic characteristics (marital status, occupational history and quality of present living accommodation) was found to be predictive, though analysis of larger samples or pooled research data would be necessary to establish their importance in this respect. The findings suggest that identification of mild cognitive impairment on screening could prove helpful in assessing risk for dementia from two to three years before the condition becomes clinically apparent.

Aged↗
PubMed1994

Sociology in the context of social psychiatry.

The author addresses various aspects of the interface between sociology and social psychiatry, among them the labelling process related to mental deviance, problems related to diagnosis and social ethology. The need for interdisciplinary work is emphasized, not least in the context of prevention. It is underlined that effective preventive measures can precede the full causal elucidation of a disease.

Community Psychiatry↗
PubMed1994

Folnegović & Folnevogić-Smalc's "Schizophrenia in Croatia: inter-regional differences in prevalence and a comment on constant incidence".

"STUDY OBJECTIVE--The aim was to examine why differences exist in schizophrenia prevalence and risk in some areas of Croatia, when schizophrenia incidence rates do not appear to vary. DESIGN--Areas differing by schizophrenia admission rates in patients born in 1953 and admitted by the age of 31 years are compared using a number of indicators relating both to general population characteristics and to those of schizophrenic cases in these populations. SETTING--The study covers the whole of Croatia (4,601,469 inhabitants, 1981 census). SUBJECTS--By the age of 31 years, out of 80,445 individuals born in Croatia in 1953, 464 were admitted for and diagnosed as having schizophrenia. MAIN RESULTS--Admission risk rates are higher in those parts of Croatia where emigration rates are high and lower where immigration rates are high. There is also a positive correlation with schizophrenia prevalence and manic depressive psychosis rates. There is a negative correlation with age of onset of schizophrenia and with schizophrenic reproduction rates. In the study areas, hospital incidence rates are not significantly different. CONCLUSIONS--Economic migration and negative selection in the domestic population are likely to be the most significant factors leading to differences in schizophrenia prevalence. The approximately equal incidence rates in the population, with different prevalence and admission risks, are linked to differences in the disease onset among schizophrenics with a positive family history for this condition. In other words, these patients, when part of the population with a greater prevalence and a greater hereditary loading, experience the onset more often at an earlier age. Thus they have a lower reproduction rate than in a population with a lower prevalence and a lower hereditary loading. Thus incidence rates in populations with different prevalences and different hereditary loads are maintained roughly equal over generations."

Adolescent↗
PubMed1994

Person-environment assessments in occupational therapy.

Occupational therapists have begun to recognize the importance of considering how the environment influences occupational performance. Models of person-environment fit provide a theoretical context within which occupational therapists can consider the influence of the environment on function. The challenge for occupational therapists is to select assessments that incorporate concepts of person-environment fit. However, limited awareness of appropriate environmental assessments that have undergone psychometric testing has limited their introduction into clinical practice. This paper reviews 41 environmental assessments and considers each in terms of its purpose, environmental attribute, environmental application, clinical utility, instrument development, and psychometric testing. A case example illustrates the applicability to the practice of occupational therapy.

Activities of Daily Living↗
PubMed1993

Beam shaping for microwave waveguide hyperthermia applicators.

PURPOSE: Hyperthermia treatments commonly use single element microwave waveguide applicators. The microwave beam patterns produced by these applicators are often non-uniform. As a result, hot spots are formed in the heated tissue and therapeutic temperatures are reached in only small areas of the treatment field. We have constructed new coupling boluses that improve the heating patterns of external microwave applicators. METHODS: The microwave beam transmitted through the bolus is modified by microwave absorbing saline/gelatin pads. The pads can be designed to result in a uniform heating pattern over a large area or alternatively, complex heating patterns can be generated for specific clinical applications. An analysis of the effect of bolus design parameters on microwave absorption patterns is presented. The heating patterns of the MA-100 and MA-120 microwave waveguide applicators have been measured in muscle and fat phantom materials with both the manufacturer's boluses and the new boluses. RESULTS: In the case of the MA-100, the area above the 70% heating level measured in a muscle phantom was increased by a factor of 2.3 by an absorbing pad bolus. Similarly, the heating area of the MA-120 was increased by a factor of 2.6 by an absorbing pad bolus. The boluses were tested in a clinical setting by measuring tissue temperature profiles in patients under different bolus arrangements. The area over which therapeutic temperature was achieved was increased considerably when the absorbing bolus was used. A second bolus was designed for the MA-120 to produce a ring heating pattern for the treatment of a breast cancer patient who had developed recurrences at the periphery of a skin graft. The heating pattern produced in a muscle phantom is compared with tissue temperature profiles measured during the hyperthermia treatment of this patient. CONCLUSIONS: Microwave absorbing filters using saline pads significantly improve the heating patterns of microwave waveguide hyperthermia applicators. This improvement was confirmed in clinical application where much greater areas of homogeneous heating were observed. The technology was extended to produce complex heating patterns for special clinical applications.

Breast Neoplasms↗
PubMed1993

Parallels between properties of high-threshold mechanoreceptors of the goat oral mucosa and human pain report.

In the following experiments, we examined parallels between properties of A-delta high-threshold mechanoreceptors (HTMs; mechanonociceptors, MN, and intense pressure receptors, IPR) innervating the goat mucosa and human mucosal pain report. As suggested in previous studies, activation thresholds of afferents which are generally considered to be mechanical nociceptors are far below mechanical pain thresholds. It was determined that classification of nociceptors by frequency thresholds, i.e., the pressure at which HTMs maintained a minimum frequency (97 g/mm2 and 117 g/mm2 for IPRs and MNs respectively) brings afferent reactivity into alignment with perceptual events. The range of reactivity of the nociceptor pool paralleled pain report from "faint-weak" (142 g/mm2) to "strong-intense" (277 g/mm2). It is suggested that coding of intense mechanical pain from compressive forces is likely to arise from both individual afferents, whose reactivity spanned the range, and from recruitment of afferent populations with progressively higher thresholds.

Afferent Pathways↗
PubMed1993

Single spies and battalions: the clinical epidemiology of mental disorders.

Clinical epidemiology, a term that has been variously defined, is used here to refer to a discipline which, commencing with examination and diagnosis of the individual patient who presents in medical practice, proceeds to study the occurrence of similar, possibly connected cases in the local community, and in so doing may provide hypotheses for population-based studies of disease and its risk factors. While the relevance of this discipline to the modern practice of clinical psychiatry remains largely unexplored, its importance in the search for causes of mental disorder is attested by many instances, both historical and more recent, in which the spread or clustering of psychiatric syndromes in populations could be related to nutritional deficiency, infectious disease, the presence of environmental neurotoxins, the social communication of psychopathology or the transmission of abnormal, harmful behaviour patterns within family groups. Observations made in clinical practice have repeatedly served as the starting point for epidemiological investigation of mental disorders, while conversely epidemiological findings have influenced clinical thinking about their classification, diagnosis, prognosis and morbid risk. A review of the relevant literature underlines the need for a keener awareness of environmental risk factors and a fundamentally epidemiological frame of reference in trying to grapple with the aetiological problems of mental disorder.

Disease Outbreaks↗
PubMed1993

Contribution of edema to the sensitization of high-threshold mechanoreceptors of the goat palatal mucosa.

1. Carrageenan has been shown to alter transduction capacities of high-threshold mechanoreceptors of the goat palatal mucosa. Assessments were made of the contributions of carrageenan-induced edema to the sensitization of mechanonociceptors (mechanically insensitive afferents) and intense pressure receptors of the palatal mucosa of the goat. The degree of edema was assessed by measurement of changes in tissue compliance produced by carrageenan. The impact of a simulated edema on both dynamic and static aspects of transduction were examined. The following observations were made. 2. Tissue compliance of the ventral zone of the incisal papilla (IP) was decreased after carrageenan treatment (0.042-0.014 mm/g). Tissue compliance changes were large for small displacements (< 1.4 mm), where displacement curves were substantially linear. For large displacements (> 1.4 mm), there was an exponential relationship between displacement and reactive force, and the compliance was unchanged. The exponential component may have represented the contribution of the maxillary bone compliance measures. 3. A simulated edema was created to assess the effects of edema on afferent reactivity. Saline was used to create the simulated edema by using changes in tissue compliance as a means of matching simulated to carrageenan-induced edema. An analysis of linear and exponential phases of saline or carrageenan-induced changes in tissue compliance indicated that saline injections produced a good approximation of the changes in linear properties, but diverged from a match of the exponential phase of carrageenan edema. 4. Assessments were made of modifications in nociceptor reactivity after simulated edema or retested controls (n = 47). There was little indication that edema influenced quantitative aspects of either static or dynamic force transduction. Mechanonociceptors, but not intense pressure receptors, sensitized after repeated intense stimulation (mean decline of dynamic activation threshold of 42 +/- 16 g/mm2, mean +/- SE). Artificial edema did not further contribute to this sensitization. 5. Qualitative features of stimulus transduction were modified by simulated edema. Eleven of 17 afferents without initial static or dynamic transduction capacity acquired the capacity after artificial edema. 6. Although most aspects of force transduction were unaffected by artificial edema, displacement transduction was considerably shifted. Artificial edema decreased the threshold and shifted the displacement range over which nociceptors transduced dynamic and static aspects of force (threshold decreased from 1,894 +/- 229 to 1,456 +/- 194 microns; range decreased 239 +/- 99 microns). 7. It was concluded the contribution of edema to allodynia and hyperalgesia is best understood in terms of its contribution to population-coding mechanisms that are brought about by changes in transmission properties.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1993

[Dementias and management of elderly patients by the Mannheim social service].

The management of dementing disorders among the elderly is gaining in importance as a public-health objective. In recent years, a number of studies in Germany have indicated a relatively high frequency of organic brain syndromes among the elderly patients of the "Sozialstationen" (community nursing services). A survey was carried out of all over-65-year-old patients (n = 1842) cared for during one month by such units in the city of Mannheim. The level of cognitive functioning of each patient was rated by the nurses, and the different forms of care provided were recorded. The research findings confirm that dementia and related conditions occur frequently in this patient population. The nurses rated 11 per cent of the patients as clinically demented and a further 14 per cent as suffering from milder cognitive disorders ("mild dementia"). While the number of items of care directly related to medical treatment remained fairly constant, the frequency of all measures of basic nursing care increased in direct proportion to the degree of the patient's cognitive impairment. These findings have implications for the future organization and development of community nursing services.

Aged↗
PubMed1993

[Psychiatric disorders in elderly general hospital patients: incidence and long-term prognosis].

As part of a survey conducted in six general-hospital departments of internal medicine, in the neighbouring cities of Mannheim and Ludwigshafen (total pop. 470,000), 626 patients in the age range 65 to 80 years, all admitted from private addresses, were screened by means of a standardized questionnaire (Cognitive and Affective Screening of the Elderly--'CASE'). All patients whose scores indicated possible mental abnormality, together with a proportion of those having normal scores, were then examined in greater detail, using the Clinical Psychiatric Interview. Following correction, the screening results indicated a frequency of 30.2% for clinically significant psychiatric disturbance, made up of 9.1% with organic mental disorders and 21.1% with functional mental illness only. These rates are considerably higher than could be expected on the basis of a field study of the background population. One year after hospital discharge, the numbers of deaths and of admissions to long-stay care were established for the whole sample, and in addition, individually matched sub-samples of 100 mentally ill and 100 mentally normal patients were reinvestigated. A second follow-up of the matched sub-samples was undertaken after a further interval of 5.6 years on average. The results of follow-up show that 75% of the identified cases ran a chronic or recurring course, while only a small proportion proved to be transient reactions to physical illness or hospital admission. In general, the psychiatrically ill patients had a relatively unfavourable outcome, even after the effects of age, physical disability and other relevant variables had been controlled for. When compared with the matched group of mentally normal patients, they manifested a 43% excess of mortality, and an increase of 157% in the risk for having to be admitted to long-stay care.

Activities of Daily Living↗
PubMed1992

DNA binds and activates complement via residues 14-26 of the human C1q A chain.

The mechanism by which DNA activates the classical complement pathway was investigated, with emphasis upon the C1q binding sites involved. DNA bound to both the collagen-like and globular regions of C1q. Binding reactivity with DNA was retained after reduction/alkylation and sodium dodecyl sulfate treatment of C1q. DNA bound preferentially to the A chain of C1q. Binding sites for DNA were localized by using synthetic C1q A chain peptides to two cationic regions within residues 14-26 and 76-92, respectively. Peptides 14-26 and 76-92 avidly bound DNA in enzyme-linked immunosorbent and gel shift assays. Peptide 14-26 also precipitated with DNA and blocked its ability to bind C1q and activate C. Replacement of the two prolines with alanines or scrambling the order of the amino acids resulted in loss of ability of peptide 14-26 to inhibit C1q binding and complement activation by DNA; similar investigations showed a sequence specificity for peptide 76-92 as well. These experiments identify C1q A chain residues 14-26 as the major site, and residues 76-92 as a secondary site, through which DNA binds C1q and activates the classical complement pathway, and demonstrate that a peptide identical to residues 14-26 can modulate C1q binding and complement activation by DNA.

Amino Acid Sequence↗