[Differences between German and Turkish-speaking participants in a chronic heart failure management program]. / Unterschiede zwischen deutsch- und türkischsprachigen Teilnehmenden an einem strukturierten Herzinsuffizienz-Versorgungsmodell.

BACKGROUND: German and Turkish-speaking patients were recruited for a chronic heart failure management program. So far little is known about the special needs and characteristics of Turkish-speaking patients with chronic heart failure; therefore, the aim of this study was to examine sociodemographic and illness-related differences between German and Turkish-speaking patients with chronic heart failure. METHODS: German and Turkish-speaking patients suffering from chronic heart failure and insured with the AOK Rheinland/Hamburg or the BARMER GEK health insurance companies and living in Cologne, Germany, were enrolled. Recruitment took place in hospitals, private practices and at information events. Components of the program were coordination of a guideline-oriented medical care, telemonitoring (e.g., blood pressure, electrocardiogram, and weight), a 24-h information hotline, attendance by German and Turkish-speaking nurses and a patient education program. Data were collected by standardized interviews in German or Turkish language. Data were analyzed with descriptive measures and tested for significance differences using Pearson's χ2-test and the t­test. RESULTS: A total of 465 patients (average age 71 years, 55 % male and 33 % Turkish-speaking) were enrolled in the care program during the study period. Significant differences between German and Turkish-speaking patients were found for age, education, employment status, comorbidities, risk perception, knowledge on heart failure and fear of loss of independence. DISCUSSION: The response rate could be achieved with the help of specific measures for patient enrollment by Turkish-speaking integration nurses. The differences between German and Turkish-speaking patients should in future be taken into account in the care of people with chronic heart failure.

[Qualitative Research in Health Services Research - Discussion Paper, Part 3: Quality of Qualitative Research]. / Qualitative Studien in der Versorgungsforschung - Diskussionspapier, Teil 3: Qualität qualitativer Studien.

The third and final discussion paper of the German Network of Health Services Research's (DNVF) "Qualitative Methods Working Group" demonstrates methods for the evaluation and quality of qualitative research in health services research. In this paper we discuss approaches described in evaluating qualitative studies, including: an orientation to the general principles of empirical research, an approach-specific course of action, as well as procedures based on the research-process and criteria-oriented approaches. Divided into general and specific aspects to be considered in a qualitative study quality evaluation, the central focus of the discussion paper undertakes an extensive examination of the process and criteria-oriented approaches. The general aspects include the participation of relevant groups in the research process as well as ethical aspects of the research and data protection issues. The more specific aspects in evaluating the quality of qualitative research include considerations about the research interest, research questions, and the selection of data collection methods and types of analyses. The formulated questions are intended to guide reviewers and researchers to evaluate and to develop qualitative research projects appropriately. The intention of this discussion paper is to ensure a transparent research culture, and to reflect on and discuss the methodological and research approach of qualitative studies in health services research. With this paper we aim to initiate a discussion on high quality evaluation of qualitative health services research.

Can a stressed oncologist be good in a consultation? A qualitative study on the oncologists' perception.

The aim of this exploratory study was to examine how the working conditions and job stress of private practice oncologists (PPOs) affect their interaction with patients. Data for the study were collected through semi-structured interviews with PPOs selected based on purposeful sampling criteria. The data were evaluated using content analysis. Factors perceived by PPOs to influence their level of stress and patient care were some of their own personal characteristics as well as working conditions both within and outside their practices. Apart from being able to name specific stressors (e.g., dysfunctional organisational workflow and interruptions during medical encounters), the oncologists also mentioned individual and organisational resources (e.g., professional experience, well-educated nurses and good work organisation) for coping with job stress and improving interaction with patients. Within this study, we identified some obstacles on the individual and organisational level for good patient care, as working conditions which might lead to time pressure and stress, which subsequently have an impact on quality in patient care (e.g., less time for personal issues during patient consultations). Future stress research should conduct a more in-depth investigation of these and other interventions at both the individual and organisational levels in order to improve patient care.

[Thrombolysis for acute stroke--a nationwide analysis of regional medical care]. / Thrombolyse des akuten Schlaganfalls--Eine deutschlandweite Analyse der regionalen Versorgung.

BACKGROUND: This study aims at investigating ischaemic stroke therapy in Germany by using secondary data. The focus lies on the performance of thrombolysis. METHODS: Statutory quality report data for 2010 were obtained. All hospitals (n = 1302) treating patients suffering from an ischaemic stroke either on a neurological, internal, geriatric or intensive care unit were analysed. The treatment situation, defined as the experience in performing thrombolysis, was displayed cartographically. Potential variables that may influence the thrombolysis rate were analysed. RESULTS: 78 % of the 198,500 ischaemic stroke cases were treated on a ward specialised in the stroke treatment (i. e., a stroke unit). The mean thrombolysis rate in neurological departments was 9.1 %. Thrombolysis rates between departments ranged from 0 to 38 %. Significant factors influencing the thrombolysis rate were the total number of ischaemic strokes treated as well as the existence of a stroke unit. DISCUSSION: In Germany, to date regional differences in the treatment of ischaemic stroke exist. Experience in the treatment of ischaemic stroke patients and the availability of a stroke unit both increase the thrombolysis rate. Data suggest that in Germany there is still room for improvement of appropriate ischaemic stroke treatment.

[Qualitative research in health services research - discussion paper, Part 1: What is the idea?]. / Qualitative Studien in der Versorgungsforschung - Diskussionspapier, Teil 1: Gegenstandsbestimmung.

In this first part of a 3-part discussion paper the working group "Qualitative Methods" in the German Network of Health Services Research (DNVF) identifies the potentials and opportunities qualitative research methods provide for health services research. Many research questions relevant for health services research require the use of qualitative methods. However, the potential of and need for qualitative research in health services research has not yet received sufficient attention from funding bodies. We discuss the applicability and importance of qualitative research for the field of health services research. We then move on to describe the key characteristics of qualitative research that need to be taken into account in health services research. We discuss characteristics such as open-ended (qualitative) data, interpretation of meanings, the search for contradictions, closeness to everyday life, openness towards change or modification of the research question and processes in the context of health services research. To ensure a high-quality approach in qualitative methods for the health services research, sufficient competency in methods and appropriate settings that account for the peculiarities of qualitative methods need to be developed. These include an appropriate time frame and sufficient and qualified personnel to conduct qualitative research. Qualitative research is not a research paradigm in itself rather it comprises of many different and diverging approaches. The goal of this paper is to show the diversity of qualitative research methods, its importance for health services research, and to open up the discussion on strategies for integrating qualitative methods into health services research.

[Qualitative research in health services research - discussion paper, Part 2: Qualitative research in health services research in Germany - an overview]. / Qualitative Studien in der Versorgungsforschung - Diskus-sionspapier, Teil 2: Stand qualitativer Versorgungsforschung in Deutschland - ein exemplarischer Überblick.

BACKGROUND: This is the second part of a 3-part discussion paper by the working group on "Qualitative Methods" in the German network of health services research (DNVF) that shall contribute to the development of a memorandum concerning qualitative health services research. It aims to depict the different types of qualitative research that are conducted in health services research in Germany. In addition, the authors present a specific set of qualitative data collection and analysis tools to demonstrate the potential of qualitative research for health services research. QUALITATIVE RESEARCH IN HEALTH SERVICES RESEARCH - AN OVERVIEW: To give an overview of the types of qualitative research conducted in German health services research, the abstracts of the 8th German Conference on Health Services Research were filtered to identify qualitative or mixed-methods studies. These were then analysed by looking at the context which was studied, who was studied, the aims of the studies, and what type of methods were used. Those methods that were mentioned most often for data collection and analysis are described in detail. QUALITATIVE RESEARCH AT THE CONFERENCE FOR HEALTH SERVICES RESEARCH 2009: Approximately a fifth of all abstracts (n=74) had a qualitative (n=47) or a mixed-methods approach combining quantitative and qualitative methods (n=27). Research aims included needs assessment (41%), survey development (36%), evaluation (22%), and theorizing (1%). Data collection mostly consisted of one-on-one interviews (n=45) and group discussions (n=29). Qualitative content analysis was named in 35 abstracts, 30 abstracts did not reference their method of analysis. In addition to a quantitative summary of the abstract findings, the diversity of fields addressed by qualitative methods is highlighted. CONCLUSION: Although drawing conclusions on the use of qualitative methods in German health services research from the analysis of conference abstracts is not possible, the overview we present demonstrates the diversity of methods used for data collection and analysis and showed that a few select methods are extensively used. One of the tasks a memorandum of qualitative health services research should accomplish is to highlight underutilized research methods, which may help to develop the potential of qualitative methodology in German health services research.

[Methods for organisational health services research]. / Methoden für die organisationsbezogene Versorgungsforschung.

On 1 July 2009, the German Network for Health Services Research [Deutsches Netzwerk Versorgungsforschung e. V. (DNVF e. V.)] approved the Memorandum III "Methods for Health Services Research", supported by the member societies mentioned below and published in this journal (Gesundheitswesen 2009; 71: 505-510). The focus of this part of the Memorandum III "Methods for health services research" is on the questions and methods of organisational health services research. In a first step, we describe the central questions which are at the core of organisational health services research. In a second step, we describe the methodological standards and requirements with regard to a) sampling, b) measurement and c) research design. We present a phase model for complex intervention trials. This model allows to conduct high quality organisational health services research, to integrate different methods of social research and to show in which phase they are of special importance.

[A rare cause of hepatic coma]. / Seltene Ursache eines hepatisch bedingten Komas.

CASE REPORT: A 65-year-old female patient was admitted to the hospital in somnolent state. During physical examination, she had an increase in blood pressure and a positive bilateral Babinski's sign. Laboratory findings showed elevated liver enzymes, metabolic alkalosis and slightly elevated kidney values. 3 h hours later she lapsed into a hepatic coma (ammonia > 400 micrograms/dl). Subsequently, indirect anamnesis revealed the following affections: ureterosigmoidostomy in 1942, cystectomy in 1943, and right-sided nephrectomy in 1950. DISCUSSION: This case presents with an uncommon origin of the hepatic encephalopathy: in the operated colon, bacterial overgrowth (bacteriogenic ureapoiesis) developed, which led to a hyperammonemia. Furthermore, in mild alcoholic liver disease--as in this case--ammonia cannot be metabolized to urea and leads to hepatic encephalopathy. We considered making this part of the colon poor in bacteria (by consequent administration of antibiotics), thus reducing the formation of ammonia.

Localization of organic cation transporters OCT1 and OCT2 in rat kidney.

Renal excretion and reabsorption of organic cations are mediated by electrogenic and electroneutral organic cation transporters, which belong to a recently discovered family of polyspecific transporters. These transporters are electrogenic and exhibit differences in substrate specificity. In rat, the renal expression of the polyspecific cation transporters rOCT1 and rOCT2 was investigated. By in situ hybridization, significant amounts of both rOCT1 and rOCT2 mRNA were detected in S1, S2, and S3 segments of proximal tubules. By immunohistochemistry, expression of the rOCT1 protein was mainly observed in S1 and S2 segments of proximal tubules, with lower expression levels in the S3 segments. At variance, rOCT2 protein was mainly expressed in the S2 and S3 segments. Both transporters were localized to the basolateral cell membrane. Neither rOCT1 nor rOCT2 was detected in the vasculature, the glomeruli, and nephron segments other than proximal tubules. The data suggest that rOCT1 and rOCT2 are responsible for basolateral cation uptake in the proximal tubule, which represents the first step in cation secretion.

Membrane localization of the electrogenic cation transporter rOCT1 in rat liver.

The polyspecific cation transporter rOCT1 in the rat was the first identified member of a new protein family with 12 presumed membrane-spanning alpha-helices and two large hydrophilic loops. Previous studies showed that rOCT1 is mainly expressed in liver and mediates electrogenic uptake of small organic cations into cells. Antibodies against partial sequences of rOCT1 were raised and their specificity was verified. Immunohistochemistry with rat liver and Western blots with isolated membranes showed that rOCT1 is localized within sinusoidal membranes of hepatocytes. Antibody reactions were also performed with intact and permeabilized human embryonic kidney cells that were stably transfected with rOCT1. They showed that the large hydrophilic loop after the first alpha-helix of rOCT1 is located extracellularly, while the C-terminus is located intracellularly. Translational regulation is suggested since the message of rOCT1 was distributed throughout the liver lobuli, whereas rOCT1 protein was observed only in hepatocytes surrounding the central veins.

Human neurons express the polyspecific cation transporter hOCT2, which translocates monoamine neurotransmitters, amantadine, and memantine.

Recently, we cloned the human cation transporter hOCT2, a member of a new family of polyspecific transporters from kidney, and demonstrated electrogenic uptake of tetraethylammonium, choline, N1-methylnicotinamide, and 1-methyl-4-phenylpyridinium. Using polymerase chain reaction amplification, cDNA sequencing, in situ hybridization, and immunohistochemistry, we now show that hOCT2 message and protein are expressed in neurons of the cerebral cortex and in various subcortical nuclei. In Xenopus laevis oocytes expressing hOCT2, electrogenic transport of norepinephrine, histamine, dopamine, serotonin, and the antiparkinsonian drugs memantine and amantadine was demonstrated by tracer influx, tracer efflux, electrical measurements, or a combination. Apparent Km values of 1.9 +/- 0.6 mM (norepinephrine), 1.3 +/- 0.3 mM (histamine), 0.39 +/- 0.16 mM (dopamine), 80 +/- 20 microM (serotonin), 34 +/- 5 microM (memantine), and 27 +/- 3 microM (amantadine) were estimated. Measurement of trans-effects in depolarized oocytes and human embryonic kidney cells expressing hOCT2 suggests that there were different rates and specificities for cation influx and efflux. The hypothesis is raised that hOCT2 plays a physiological role in the central nervous system by regulating interstitial concentrations of monoamine neurotransmitters that have evaded high affinity uptake mechanisms. We show that amantadine does not interact with the expressed human Na+/Cl- dopamine cotransporter. However, concentrations of amantadine that are effective for the treatment of Parkinson's disease may increase the interstitial concentrations of dopamine and other aminergic neurotransmitters by competitive inhibition of hOCT2.

Cloning and characterization of two human polyspecific organic cation transporters.

Previously we cloned a polyspecific transporter from rat (rOCT1) that is expressed in renal proximal tubules and hepatocytes and mediates electrogenic uptake of organic cations with different molecular structures. Recently a homologous transporter from rat kidney (rOCT2) was cloned but not characterized in detail. We report cloning and characterization of two homologous transporters from man (hOCT1 and hOCT2) displaying approximately 80% amino acid identity to rOCT1 and rOCT2, respectively. Northern blots showed that hOCT1 is mainly transcribed in liver, while hOCT2 is found in kidney. Using in situ hybridization and immunohistochemistry, expression of hOCT2 was mainly detected in the distal tubule where the transporter is localized at the luminal membrane. After expression in Xenopus laevis oocytes, hOCT1 and hOCT2 mediate tracer influx of N-1-methylnicotinamide (NMN), tetraethylammonium (TEA), and 1-methyl-4-phenylpyridinium (MPP). For cation transport by hOCT2 apparent K(m) and K(i) values were determined in tracer flux measurements. In addition, electrical measurements were performed with voltage-clamped oocytes. Similar to rOCT1, cation transport by hOCT2 was pH independent, electrogenic, and polyspecific; however, the cation specificity was different. In voltage-clamped hOCT2-expressing oocytes, inward currents were induced by superfusion with MPP, TEA, choline, quinine, d-tubocurarine, pancuronium, and cyanine863. Cation transport in distal tubules is indicated for the first time. Here hOCT2 mediates the first step in cation reabsorption. hOCT1 may participate in hepatic excretion of organic cations.

Expression of the Na+-D-glucose cotransporter SGLT1 in neurons.

In brains of the rabbit, pig, and human, expression of the high-affinity Na+-D-glucose cotransporter SGLT1 and of the protein RS1, which alters the activity of SGLT1, was demonstrated. In situ hybridization showed that SGLT1 and RS1 are transcribed in pyramidal cells of brain cortex and hippocampus and in Purkinje cells of cerebellum. In neurons of pig brain SGLT1 protein was demonstrated by western blotting with synaptosomal membranes and by immunohistochemistry, which showed SGLT1 in pyramidal and Purkinje cells. To test whether SGLT1 in neurons may be activated during increased D-glucose consumption, an epileptic seizure was induced in rat brain, and the uptake of specific nonmetabolized substrates of SGLT1 [[14C]methyl-alpha-D-glucopyranoside ([14C]AMG)] and of Na+-independent transporters [2-deoxy-D-[14C] glucose ([14C]2-DG)] was analyzed by autoradiography. During the seizure the uptake of AMG and 2-DG was increased in the focus. Within two hours after the seizure 2-DG uptake in the focus returned to normal. In contrast, the AMG uptake in the focus area was still increased 1 day later. The data show that the high-affinity Na+-D-glucose cotransporter SGLT1 is expressed in neurons and can be up-regulated.

Elevated cell-associated levels of interleukin 1beta and interleukin 6 in inflamed mucosa of inflammatory bowel disease.

The aim of this study was to investigate the involvement of the monocyte-derived cytokines interleukin 1beta (IL-1beta), interleukin 6 (IL-6) and tumour necrosis factor-alpha (TNF-alpha) in idiopathic inflammatory bowel disease. Endoscopic biopsies of normal and inflamed intestinal mucosa were obtained from patients with ulcerative colitis (n = 11) and with Crohn's disease (n = 10). Intestinal mucosal cells were isolated by collagenase digestion. Cell viability, morphology and CD14 expression were determined. To measure cell-associated cytokine levels, cells were lysed and analysed for IL-1beta and TNF-alpha in specific radioimmunoassays and for IL-6 using a biological assay. Compared with mucosal cells from control patients without inflammatory bowel disease the inflamed intestine in ulcerative colitis and Crohn's disease displayed markedly enhanced levels of IL-1beta (median 245 pg 10(-6) cells, range 30-1275) and IL-6 (median 22 U 10(-6) cells, range 1-298). Non-inflamed mucosa in patients with ulcerative colitis and Crohn's disease did not show elevated levels of IL-1beta (median 50 pg 10(-6) cells, range 33-90) or IL-6 (mean below detection limit of assay, i.e. 1 U 10(-6) cells). In contrast, no clear cut difference between inflamed and non-inflamed mucosa could be detected for TNF-alpha. High tissue levels of IL-6 were associated with a high endoscopic grade of local inflammation. These results suggest that the monocyte-derived cytokines IL-1beta and IL-6 are mediators of inflammation in inflammatory bowel disease.

[Gastrointestinal involvement in progressive systemic scleroderma]. / Gastrointestinale Beteiligung bei progressiv-systemischer Sklerodermie (PSS).

The complained gastrointestinal symptoms in PSS are probably caused by several complex disturbances like intestinal transit disturbances (ITD), bacterial overgrowth of the small intestine caused malabsorption of bile acids and altered kinetics of intestinal hormones. 25 patients with PSS and eleven healthy controls were tested for the existence of ITD by use of the metal-detector test (MDT). Twelve patients were also tested for a malabsorption of primary bile acids by radioimmunological measurement of clolylglycine serum levels before and after a meal. In addition serum concentrations of gastrin (nine patients) and plasma concentrations of cholecystokinin (CCK) (eight patients) and motilin (eleven patients) were measured by radioimmunoassay pre- and postprandial. Interdigestive gastric emptying was accelerated in patients with PSS (53 +/- 3 min. vs. 73 +/- 7 min.; p<0.01). Small intestinal transit times were similar in both groups (115 +/- 17 min. vs. 121 +/- 13 min.). Colonic transit in patients with PSS was significant prolonged (63 +/- 6 h vs. 39 +/- 5 h; p<0.05). There were no significant differences between the two groups concerning the pre- and postprandial levels of cholylglycin. Basic and postprandial levels of gastrin, CCK and motilin were higher in the PSS group. In contrast to scintigraphic studies using semisolid meals gastric emptying of the copper pellet in PSS was accelerated. A general malabsorption of primary bile acids was not found. Prolonged colonic transit times correlate well with frequently complained obstipation. Gastric hypacidity could be the reason of elevated gastrin levels. The high motilin-levels in PSS could be due to a lack of the feed-back inhibition as a result of diminished phase-III activity of the interdigestive migrating motor complex. The elevation of CCK-levels could reflect compensation of neurogenic or myogenic disturbances of gallbladder contraction.

Measurement of transit disorders in different gastrointestinal segments of patients with diabetes mellitus in relation to duration and severity of the disease by use of the metal-detector test.

The existence of gastrointestinal transit disorders in other intestinal segments beside the stomach in Type-1 diabetes mellitus (DM) and occurrence in Type-2 DM and in uremia has yet been confirmed only in few studies. Eleven healthy volunteers, 34 patients with Type-1, 32 patients with Type-2 DM in different stages of their disease and 34 non-diabetic patients with endstage-renal disease were investigated by use of the metal detector test. Patients were divided in three subgroups, depending on the duration of their disease: < 1 year: "Short", 1 - 10 years: "Middle", > 10 years: "Long". For comparison with the metal detector test scintigraphic studies of esophageal and gastric transit were performed in 17 patients and small intestinal transit was studied by use of the H2-lactulose breath test in 20 patients with long-standing DM Type-1. In Type-1 DM there is an increase of gastric (135 +/- 18, p < 0.01; 218 +/- 26, p < 0.0001 vs. 73 +/- 7 min.) and large intestinal transit times (79 +/- 18, P < 0.02; 76 +/- 11, p < 0.04 vs. 40 +/- 5 h) in patients with middle or long standing DM. In Type-2 DM similar transit disturbances occur (gastric emptying, long group: 120 +/- 15 min., p < 0.02; colonic transit, long group: 80 +/- 13 h, p < 0.01). In uremia transit disturbances were only found in patients with chronic ambulatory peritoneal dialysis (colonic transit: 71 +/- 9 h, p < 0.05). In 65% gastric scintigraphy and in 55% of cases the H2-lactulose breath test showed a prolongation of gastric emptying or a prolonged mouth-to-cecum transit. Transit disorders can occur in every stage of DM with preferential involvement of the stomach and the colon. These findings are of clinical relevance, since transit disturbances can result in instable metabolic condition.

[Vaso-occlusive crises in sickle-cell anemia]. / Vaso-okklusive Krisen bei Sichelzellanämie.

HISTORY AND FINDINGS: Severe pain suddenly occurred in the shaft of the right thigh in a 21-year-old patient of Turkish descent with known homozygotic sickle cell anaemia. He also had marked scleral jaundice and anaemia (haemoglobin 9.1 g/dl). An X-ray film of the lower leg pointed to a bone infarct. Type of pain, partial pressure of oxygen in blood (70 mm Hg), concentration of lactate dehydrogenase and the bilirubin level (4,5 mg/dl) as signs of haemolysis, as well as the fall in haemoglobin, indicated a vascular occlusive crisis in sickle cell anaemia. TREATMENT AND COURSE: The symptoms regressed within 8 days of the patient receiving fluids, analgesics and oxygenation by nasal tube. A few weeks later he developed a fever, productive cough and severe pain in joints and abdomen. Blood p02 was 54 mm Hg. Pneumonia in the right lung base was the cause of this renewed life-threatening crisis, which was again associated with haemolysis. Klebsiella having been found in sputum he was treated with cefotaxim (1 g twice daily intravenously) and oxygen insufflation via nasal tube (7 l/min). His condition quickly improved. CONCLUSIONS: In patients with sickle cell anaemia it is important (1) to regard crises as potentially life-threatening conditions, (2) to detect and treat infections as possible causes early and (3) to provide sufficient oxygen insufflation quickly, especially in pulmonary infections.

Calibration of misonidazole labeling by simultaneous measurement of oxygen tension and labeling density in multicellular spheroids.

To correlate misonidazole concentrations and oxygen pressures (Po2) at identical locations within EMT6/Ro multi-cell spheroids (mean diameters +/- SD: 867 +/- 20 microns), Po2 measurements were performed with oxygen-sensitive microelectrodes during incubation of these spheroids with tritiated misonidazole (10 mg/I; 445 microCi/mg). In each individual spheroid, Po2 profiles were correlated with the corresponding spatial distribution of misonidazole as quantified by conventional autoradiography and grain counting. To compare the oxygenation status of spheroids in the measuring chamber with that of spheroids in spinner culture, misonidazole labeling was performed in both environments following the same protocol. All experiments were conducted in 20% oxygen and BME or in 5% oxygen and DMEM to obtain spheroids with different degrees of oxygenation. Labeled misonidazole was fairly evenly distributed in the outer, better oxygenated regions of EMT6 spheroids. In contrast, there was an accumulation of the labeled substance near central necrosis where low oxygen tensions were measured. Grain densities were similar at corresponding oxygen pressures under both environmental conditions. Except for some scatter, grain density as a function of oxygen pressure showed little variation in the Po2 range of 20-60 mm Hg, but exhibited a steep increase below 10 mm Hg. The findings imply that a substantial rise in local misonidazole labeling indicates a metabolically active tissue region at low Po2 that is not necessarily identical with the radiobiologically hypoxic cell fraction. A comparison of the labeling densities of spheroids in spinner flasks and in the Po2 measuring chamber indicates that oxygenation of spheroids is better in rotation culture than during microelectrode measurements.