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B Cooper

Publications and source records attributed to B Cooper.

At least 73 records · Page 4Linked to original sources
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

Roxithromycin versus cefaclor in lower respiratory tract infection: a general practice pharmacoeconomic study.

An economic evaluation comparing roxithromycin 150mg twice daily and cefaclor 250mg thrice daily in the treatment of lower respiratory tract infections (LRTI) was undertaken as part of a randomised clinical trial in New Zealand general practice. The observed statistically significant difference in adverse events, withdrawal rates and extra treatment courses in favour of roxithromycin in the clinical study was translated into medical cost savings. Treatment failures, withdrawals or adverse events resulted in additional costs for 11 of 120 (9%) patients receiving roxithromycin and 19 of 118 (16%) patients receiving cefaclor. In these cases (treatment failures, withdrawals, adverse effects) additional antibiotics and general practitioner visits were required 3 times more often and the cost of additional medication for treating failure or adverse effects was 3 times higher for patients treated with cefaclor than for patients receiving roxithromycin. The total direct medical cost per patient treated with roxithromycin was $NZ9.37 lower (on an incremental basis) than for patients treated with cefaclor, despite a higher drug acquisition cost. An estimate of $NZ656 000 per year in total savings in direct medical costs could be made in New Zealand if roxithromycin were to replace all cefaclor prescriptions in the treatment of LRTI.

Cefaclor↗
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↗
PubMed1992

Percutaneous gastrostomy made simple.

The use of percutaneous endoscopic gastrostomy has obviated the necessity of laparotomy for enteral access. The authors propose a new technique for introduction of the gastrostomy tube. It entails use of the laparoscopic trocar to gain entrance into the gastric lumen.

Female↗
PubMed1992

Intravenous 6-thioguanine or cisplatin, fluorouracil and leucovorin for advanced non-small cell lung cancer: a randomized phase II study of the cancer and leukemia group B.

This randomized phase II study was designed to evaluate the activity of intravenous 6-thioguanine (6-TG) as a single agent and the combination of cisplatin and 5-fluorouracil (5-Fu) modulated by oral leucovorin (PFL) in patients with advanced non-small cell lung cancer (NSCLC). Eligible patients had measurable or evaluable stage III B or IV NSCLC, had no received prior chemotherapy and had a performance status of 0-2. Patients were randomized to treatment with intravenous 6-TG at 55 mg/m2 administered over 30 minutes for 5 consecutive days and repeated every 35 days, or PFL chemotherapy with cisplatin 100 mg/m2 on day 1, 5-FU 800 mg/m2/day as a continuous intravenous infusion over 5 days and oral leucovorin administered at 100 mg every 4 hours during the entire duration of the cisplatin and 5-FU infusions. PFL was repeated every three weeks. Ninety-five eligible patients were randomized, 46 to 6-TG and 49 to PFL. Response rates were 4% for 6-TG (95% confidence interval 0.5%-14.8%, 1 partial, and 1 complete response) and 29% (16.6%-43.3%) for PFL (all partial). The median time to treatment failure was 2 and 4 months, respectively, and the median survival times were 6 and 10 months, respectively. Toxicities with 6-TG were, generally, mild to moderate but severe or life-threatening granulocytopenia was observed in 21% of patients. With PFL, mucositis was dose-limiting, and 78% of patients had severe or life-threatening mucositis. This led to dose reduction of 5-FU and leucovorin during subsequent cycles or treatment termination in 82% of patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Comparison of the efficacy, safety, and therapeutic usage of HA-1A and E5 in the treatment of gram-negative sepsis.

Clinical trials have shown that the murine monoclonal antibody E5 and the human hybrid monoclonal antibody HA-1A increase survival of patients with gram-negative sepsis. However, significant reduction in mortality associated with E5's use was limited to patients who had not progressed to refractory shock. Patients treated with E5 compared to placebo receivers were also significantly more likely to experience resolution of organ failures. Significant reductions in morbidity and mortality associated with HA-1A's use were limited to patients with gram-negative bacteremia, and occurred even in patients with shock. Treatment with HA-1A also had a significant positive effect on resolution of the major complications of sepsis (shock, disseminated intravascular coagulation, acute renal failure, acute hepatic failure, or adult respiratory distress syndrome) in patients with documented gram-negative bacteremia. Both products appear to be safe, with generally mild, transient, and clinically insignificant adverse effects reported.

Antibodies, Monoclonal↗
PubMed1992

[Dementia diseases and minor cognitive impairments in elderly patients in general practice. Results of a cross-sectional study].

General practitioners in 24 Mannheim practices kept a record of all over-65-year-old patients seen during four weeks (n = 3,737), and made ratings of their cognitive functioning with the help of simple guidelines. For a sub-sample of patients (n = 407), these ratings could be compared with assessments made by the research team, on the basis of a standardized interview and test procedure (Hierarchic Dementia Scale). The research data indicate that 8% of the patients manifested clinical dementia, a further 8% so-called 'mild dementia' and 17% milder, non-disabling degrees of cognitive impairment. The proportion of affected persons in each of the groups rises steeply with increasing age above 65 yr. The ability of the practitioners to detect dementia--including the milder degrees--among their elderly patients exceeded expectation (sensitivity 92%; specificity 76%). The test-score profiles of the patients, grouped according to their own doctors' ratings, conformed to clinical concepts of the progressive course ('staging') of dementing illness, while the degree of disability in everyday life, and dependency on others, also increased steeply across the groups. These findings emphasize the importance of general medical practice for the early detection of dementia in the elderly population, and potentially also for case management.

Activities of Daily Living↗
PubMed1992

Risk factors for myocardial infarction after distal arterial reconstructive procedures.

This study identifies the preoperative, intraoperative, and postoperative factors associated with perioperative myocardial infarction (MI). The records of all patients who had distal vascular reconstructive procedures who sustained a perioperative MI were retrospectively reviewed from 1977 to 1990. From a total of 767 procedures, 18 (2.3%) patients suffered a MI. The mean time to MI after surgery was 1.8 days. Diabetes, heart murmur, and previous major amputations were identified as significant risk factors for the development of a perioperative MI. No laboratory or cardiographic data correlated with an increased risk, and the Goldman Index was inadequate in predicting perioperative MI risk.

Age Factors↗
PubMed1991

Severe masseter myonecrosis in a horse.

A 6-year-old Quarter Horse was examined because of acute, severely swollen masseter muscles (palpation of which elicited pain response), exophthalmos, severe chemosis, and protrusion of the third eyelids. Blood selenium and vitamin E concentrations, and results of feed analysis and muscle biopsy supported a diagnosis of nutritional myopathy. The horse was treated and was clinically normal 2 weeks after discharge from the hospital.

Animals↗