Effects of taxol and taxol/hyperthermia treatments on the functional polarization of cytotoxic T lymphocytes

Immunofluorescence staining, electron microscopy, and (51Cr) cytolytic release assays are used to investigate the effects of taxol and taxol/hyperthermia treatments on the microtubule organization and cytolytic activity of cytotoxic T lymphocytes (CTLs). A 4 h treatment of CTLs with 1 microM taxol results in an extensive reorganization of the microtubule system to form one to a few large microtubule bundles that extend from the centrosome. The Golgi apparatus is not disrupted by this treatment and remains associated with the microtubule organizing centre (MTOC). This microtubule reorganization has no effect on the ability of CTLs to orient their MTOC towards a bound target cell, nor on their cytolytic activity. In control CTLs, not treated with taxol, a mild hyperthermia treatment (42 degrees C, 30 min) results in an aggregation of the pericentriolar material, a loss of MTOC orientation, an inhibition of cytolytic activity, and a disorganization of the microtubule system [Knox et al.: Exp. Cell Res. 194:275-283, 1991]. In contrast, in taxol-treated CTLs the stabilized microtubule bundles are unaffected by such hyperthermia treatment; however, the other effects of hyperthermia appear identical in control and taxol-treated CTLs. These results indicate that a dynamic, radially arranged microtubule array is not required for the functional polarization of CTLs and suggest that a component of the pericentriolar material may play a key role in effecting MTOC orientation.

Effects of hyperthermia on microtubule organization and cytolytic activity of murine cytotoxic T lymphocytes

When murine cytotoxic T lymphocytes (CTL) are heated at 42 degrees C for 30 min their ability to lyse their target cells (TC) is severely impaired. When the CTL are allowed to recover at 37 degrees C, a partial recovery of cytolytic activity that peaks within 6 h is observed. A dye exclusion assay demonstrated that such a heat shock does not affect the viability of the CTL and direct microscopic observations established that their ability to bind to TC is not impaired. Therefore, the step or steps inhibited by hyperthermia are subsequent to TC recognition and binding. Kupfer et al. ((1983) Proc. Natl. Acad. Sci. USA 80, 7224-7228) demonstrated that upon binding to an appropriate TC, a rapid orientation of the Golgi apparatus and the microtubule organizing center (MTOC) occurred within the CTL so that the two organelles face the TC. This orientation is a prerequisite for efficient TC lysis. We have shown by immunofluorescence and confocal microscopy, using a monoclonal antibody to tubulin and a rabbit autoimmune serum that binds a centriole-associated protein, that the organization of the MTOC-microtubule array is disrupted by hyperthermia. EM suggests that this disorganization of the microtubules may result from an aggregation of the pericentriolar material. The recovery of cytolytic activity is coincident with the reorganization of the microtubules about the MTOC. These findings suggest that the initial inhibitory effect of hyperthermia on CTL function results from the disruption of microtubule organization.

Biologic variation of common hematologic laboratory quantities in the elderly

Analytic, within-subject, and between-subject biologic variations were estimated for leukocytes, erythrocytes, hemoglobin, hematocrit, mean cell volume (MCV), mean cell hemoglobin (MCH), mean cell hemoglobin content (MCHC), platelets, and a three-component differential count (lymphocytes, monocytes, and granulocytes in terms of both concentration and percentage of leukocytes) in cohorts of 12 male and 12 female healthy elderly subjects. The assays were performed with an Ortho ELT-800 automated analyzer. The estimates of within-subject biologic variation were similar to published data on young subjects, indicating that this aspect of homeostasis is not compromised in the elderly. The data were used to derive objective analytic goals; goals were surpassed except for assays of erythrocytes, hematocrit, and the derived MCV, MCH, and MCHC. The changes required for serial results to be significantly different were determined and found to be generally valid because most quantities have no heterogeneity of within-subject variation. All quantities had significant individuality; in consequence, conventional population-based reference values are of limited utility, and screening using reference limits will not detect latent or early disease in many subjects.

Biological variability of 26 clinical chemistry analytes in elderly people

Analytical, within-subject, and between-subject components of variation were estimated for 26 clinical chemistry analytes from duplicate analyses of 10 specimens collected from 27 healthy elderly subjects over a period of 20 weeks. Within-subject variations were similar to those generated previously by us in younger subjects. We conclude, therefore, that homeostasis is not compromised by age alone, and biological variability does not increase simply with age. All analytes except serum water had marked individuality, showing that conventional population-based reference values are of limited utility. The critical differences required for two results to be significantly (P less than or equal to 0.05) changed are not the same as those that prompt action by clinicians. Although heterogeneity of within-subject variation does exist, we believe that the critical differences generated will be useful in routine clinical decision making.

Biological variability of 26 clinical chemistry analytes in elderly people

Analytical, within-subject, and between-subject components of variation were estimated for 26 clinical chemistry analytes from duplicate analyses of 10 specimens collected from 27 healthy elderly subjects over a period of 20 weeks. Within-subject variations were similar to those generated previously by us in younger subjects. We conclude, therefore, that homeostasis is not compromised by age alone, and biological variability does not increase simply with age. All analytes except serum water had marked individuality, showing that conventional population-based reference values are of limited utility. The critical differences required for two results to be significantly (P less than or equal to 0.05) changed are not the same as those that prompt action by clinicians. Although heterogeneity of within-subject variation does exist, we believe that the critical differences generated will be useful in routine clinical decision making.

What is ... a modified essay question?

Medical education is moving to a more problem-orientated basis than was the case formerly. The Modified Essay Question has its origins in this movement, being introduced in the late 1960s as one assessment technique more suited to general practice than other traditional assessment methods. In its original form it is a paper exercise based on an evolving situation presented by a patient in primary care. Experience with the technique in different countries is briefly summarised, and its applications to assessment and to teaching are discussed. Despite shortcomings this method appears to be standing up to the test of time.

Rheumatic diseases: a general practitioner's view

Patients with rheumatic complaints are the subject of some 10% of the general practitioner's work. Approximately half of this work is related to the hitherto relatively neglected group of varied soft-tissue conditions, most of which are self-limiting and of a minor nature. Against a background of such diagnostic 'noise', the general practitioner has to remain alert for the fainter 'signal' of serious disease--rheumatic and non-rheumatic--at an early stage. Continuity of care calls on special qualities, behaviours and abilities in the doctor to boost and maintain morale, to coordinate management and to participate in team care. In addition to more traditional therapeutic measures, including analgesics, NSAIDs, disease-modifying drugs and physiotherapy, joint replacement is seen as a significant contribution. There is room for improvement in the structure process and outcomes of delivery of care as it may relate to rheumatic diseases. A simple illustration, based on a general practice audit of gout, is suggested as a possible model by which quality of care could be enhanced at the level of individual patients. While there is not a great deal of scope afforded to the general practitioner in the exercise of primary prevention of the rheumatic diseases, early diagnosis and timely support for carers of patients suffering from chronic rheumatic diseases are areas worth attention. Promotion of self-help is seen as a worthwhile activity in humanitarian and economic terms, though it calls for an appropriate balance to be struck.

Comparison of response rates to a postal questionnaire from a general practice and a research unit

A postal questionnaire study was carried out in an urban general practice to determine the effect of the introductory letter being sent by the participants' own general practitioner compared with that from a letter sent directly from a research unit. By sequential sampling 409 individuals aged between 40 and 59 were assigned to one of two groups. The people in one group were written to by their own general practitioner and those in the other by a doctor from a research unit. Husbands and wives were paired and were always sent the same letter. A second letter was sent to nonresponders after one month. The response rate to the general practitioner was significantly higher than that to the doctor in the research unit (85% compared with 75%) and differed by age and sex. The results have important implications for other research workers and suggest that general practitioners are in a key position in the conduct of medical and epidemiological research.

Communication skills teaching, learning and assessment

This paper outlines an introductory course in teaching communication skills to medical students in a preclinical context. The aims of the course, its content and teaching methods are described. Novel features include the active participation of selected patients in teaching and assessment, and the use of a form of role-play named 'listening triads'. The main focus of the paper is assessment, and results are recorded, relating to a class of 114 second-year students during the academic session 1983-84. Assessment of the students' learning was measured by Modified Essay Question (MEQ); students' problems face-to-face with patients were identified by patients, students, and by staff members observing interactions. Problems of fitting these educational assessments into a traditional academic 'certifying' type of assessment remain unresolved at present. This course was found to be acceptable by the preclinical students, and their lack of clinical knowledge did not appear to interfere with their learning. They were enthusiastic about the supervised contact with patients, which appeared to contribute significantly to the way the course was received.

Trivia, triage, and treatment

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General practitioner's care of the elderly: studies of aspects of workload

This paper reports trends in the volume and nature of general practitioners' contacts with the elderly patients on their NHS lists in Dundee during the 1970s. It forms part of a larger project involving 32 general practitioners collaborating in a continuing study concerning the introduction of the first health centre in Dundee.During the decade contacts with the elderly increased as a proportion of the general practitioners' total work, broadly commensurate with the increase in Dundee's elderly population. Indirect contacts, mainly reissue of prescriptions for longterm medication, showed a greater proportional increase than direct consultations. Home visiting of the elderly remained relatively constant, while house calls to other age groups declined. Hospital referrals remained a small proportion of the general practitioners' work. Entry into a health centre was not associated with obvious changes in patterns of workload.If more might be done in planning and implementing changes in care of the elderly at general practice level, such changes should be the result of consensus among the professionals concerned, and should take account of the views of recipients of care.

Assessment of the immunization status of practice children under five years of age

Many professional groups are involved in immunization, and four different immunization records may be kept-the general practice record, the community child health record, the health visitor record and a record retained by the parent. The first three of these sources were examined for the immunization status of children under five years of age in a practice. The health visitor record was the most comprehensive. There was a remarkable improvement in pertussis vaccine acceptance over the four years reviewed but there were gaps in the uptake of measles vaccine.

Prescribing in general practice and the provision of drug information

Duplicate prescriptions were used to monitor patient prescribing and morbidity data for 20 Tayside general practitioners during a two-year study. Each participant took part in two periods of active monitoring separated by a three-month gap. Prescribing statistics collected during the first period of monitoring formed the basis of drug information which was circulated to participants shortly after the start of the second period. Some of this information was purely statistical; other information included comments as well as statistics. Subsequent monitoring assessed any changes in prescribing. The results indicate that drug information of this kind can influence general practitioner prescribing but that there were no differences in response to information which was purely statistical and information which included comments.

Duplicate prescriptions: an aid to research and review

We describe a method of studying patterns of prescribing and related morbidity in general practice. Prescribing data were automatically duplicated onto a ;no-carbon-required' prescription-pad. Additional information about diagnosis and indications for each drug, an indication of whether the drug was newly prescribed or a repeat, and a patient identification code were entered onto the bottom copy. A computer was used to process the data, which were gathered over a period of seven months.The method offers an efficient means of collecting data which can be applied by individuals or groups of doctors to improve patient care and help achieve rational prescribing.

Debendox in early pregnancy and fetal malformation

During the mid-1960s, 22 977 pregnant women in Scotland and England were followed up prospectively for the incidence of malformations in their infants evident at birth or within six weeks. During the first 13 weeks of gestation 620 of these women had been prescribed Debendox (dicyclomine-doxylamine-pyridoxine) and 743 other women agents other than Debendox containing pyridoxine. Of the 620 women given Debendox, 589 (95%) had a normal outcome of pregnancy, 8 (13%) delivered a malformed infant, and 23 (3.7%) had other outcomes. Of the 22 357 women who were given Debendox, 445 (2.0%) produced infants with malformation; and the rates for all abnormal outcomes among women given Debendox and those not given the drug were 5.0% and 5.4% respectively. These results support the hypothesis that Debendox is not teratogenic.