Telomerase activity and telomere length in different areas of renal cell carcinoma

Telomerase activity and telomere length were analyzed in a total of 59 surgically removed primary renal cell carcinoma (RCC). The study includes tissue from the centre of the tumor, several different peripheral tumor areas, metastases and secondary tumors. None of the normal renal cortex tissues used as control exhibited telomerase activity. In contrast, telomerase activity was detected in 55 out df 59 (=93%) tested primary RCC. There was no case with intratumoral heterogeneity concerning the telomerase activity status. All metastases and secondary tumors were telomerase-positive. In the four telomerase deficient tumors all measured telomeric repeat fragments were shortened in comparison to the normal tissue. As these patients exhibit no metastases or secondary tumors a less malignant variant of RCC is supposed. There was no correlation between telomerase activity and specific histopathological subtypes of RCC or specific chromosomal aberrations. As telomerase activity is not associated with advanced stages of tumors it may be an important early event in the development of RCC. Thus, telomerase activity may be a prevalent marker for early and late stages of all subtypes of RCC.     

Clearance of thallium-201 from the peripheral blood: Comparison of immediate and standard thallium-201 reinjection

As several reinjection procedures have shown encouraging results in terms of imaging, we investigated whether the kinetics of thallium-201 would differ between the standard stress-redistribution-reinjection approach and the stress-immediate reinjection approach. In 53 consecutive patients with undiagnosed chest pain, 75 MBq (2 mCi)²⁰¹Tl was injected at maximal exercise. In 26 of these patients (group I), 37 MBq (1 mCi)²⁰¹Tl was reinjected immediately after completing the exercise images (the immediate reinjection procedure) and in 27 patients (group II), 37 MBq (1 mCi)²⁰¹Tl was reinjected after completing 3-h redistribution images (the standard reinjection procedure). Mean peak²⁰¹Tl blood activity after exercise was 17.7±12.5 kBq/ml (4.8±3.4 mCi/ml) for group I versus 16.4±9.2 kBq/ml (4.4±2.5 mCi/ml) for group II (NS). The relative increase in²⁰¹Tl blood activity after reinjection of half the initial dose [37 MBq (1 mCi)] exceeded 50% of the initial peak in both groups. The relative amount of²⁰¹Tl delivered to the myocardium was assessed by the area under the curve after both exercise and reinjection, and was 117%±72% for group I and 112%±73% for group II (NS). Blood clearance of²⁰¹Tl was at least biexponential. Mean early decay constants (₁) after exercise and reinjection were 0.30±0.18 min^–1 and 0.22±0.046 min^–1 respectively for group I (T _1/2 2.3 min and 3.2 min respectively, NS), and 0.30±0.12 min^–1 and 0.24±0.07 min^–1 respectively for group II (T _1/2 2.3 min and 2.9 min respectively, NS). For both procedures no significant differences were found between ₁ after exercise and ₁ after injection. The mean late clearance (₂) from the blood was 0.032±0.056 min^–1 and 0.012±0.012 min^–1 respectively for group I (T _1/2 21.6 min and 57.7 min respectively, NS), and 0.036±0.030 min^–1 and 0.014±0.014 min^–1 respectively for group II (T _1/2 19.3 min and 49.5 min respectively, NS). Also, no significant differences were found between ₂ after exercise for both groups and between ₂ after reinjection for both groups. We conclude that reinjection of 37 MBq (1 mCi)²⁰¹Tl (half the initial dose) results in a relative increase in the initial peak and a relative increase in the amount of²⁰¹Tl delivered to the myocardium of more than 50% for both the standard and the immediate reinjection procedure. The clearance of²⁰¹Tl from the blood was not influenced by exercise or by the time of reinjection. Based on²⁰¹Tl kinetics as measured in the peripheral blood, there is no reason to postpone reinjection until 3–4 h following exercise.     

Molecular basis of defective anion transport in L cells expressing recombinant forms of CFTR

Cystic fibrosis (CF) is caused by mutations in the gene encodinga chloride channel called the CF transmembrane conductance regulator(CFTR). A single mutation in this gene, deletion of three nucleotidesthat leads to the absence of phenylalanine 508 (i.e., F508),is found on 70% of all CF chromosomes. To explore the molecularmechanism(s) responsible for defective chloride transport inpatients with CF, we have studied the processing, localization,and function of wild type (W.T.), F508 and G551D CFTR (a GDmissense mutation at position 551) in retrovirus transducedL cells. Cell transduced with W.T. CFTR expressed a 170 kd CFTRprotein that was endoglycosidase H (Endo H) resistant, localizedto the plasma membrane, and generated a cAMP-mediated anionconductance (G_Cl) when stimulated with standard concentrationsof forskolin (5 µM), cpt cAMP (400 µM) and IBMX(100 µM). The G551D CFTR was indistinguishable from W.T.CFTR with respect to post-translational processing and localization,but it did not produce a cAMP-activated G_CI in response to thestandard stimulation cocktail. However, raising the IBMX concentrationto 4 mM produced Gc, in G551D expressing cells. Cells transducedwith F508 CFTR expressed an Endo H sensitive CFTR protein (140kd) that was found in a cytosolic, perinuclear location. Thesecells did not respond to the standard cocktail, but 20% of cellsincreased G_CI when the cocktail contained 4 mM IBMX. Incubationof cells at 26°C for 48 hours prior to analysis elicitedresponses in F508 expressing cells at low IBMX concentrations,but had no effect on the responses of cells expressing W.T.or G551D CFTR. The response of F508 to 26°C was associatedwith plasma membrane localization of CFTR protein. These resultssuggest that there are two mechanisms whereby CFTR mutationslead to loss of cAMP-responsive GCI. First, shown by G551D CFTR,the protein can be processed and targeted to the plasma membranecorrectly, but lack full responsiveness to stimulation by cAMP.Second, as examplified by F508 CFTR, a partially functionalprotein which is not targeted to its correct cellular locationcan also lead to loss of the cAMP, responsive G_CI.     

Listen to nature. The challenge of lifestyle medicine

Unlike the days of Robert Koch when infectious diseases were the principal contributors to morbidity and mortality, today's illness and death are most often caused by noncommunicable diseases that have the special characteristics of resulting largely from one's own lifestyle, especially tobacco use and nutritional excesses. By listening to nature, we can detect and identify risk factors for various types of cancer, explore their mechanisms of action, and execute preventive strategies leading to their reduction or modification, thereby, decreasing the incidence and mortality of disease. An example of the role of metabolic overload in carcinogenesis is the impact of an excessive intake of dietary fat on the development and progression of breast cancer. For the general pathogenesis of cancer, the risks associated with metabolic overloads are contrasted with those of low-level exposures. To broaden the impact of preventive medicine beyond factorial nutritional education in Germany, we recommend that (a) every medical school have a department of preventive medicine with emphasis on epidemiology and health promotion, and (b) all schools beginning in first grade have a comprehensive school health education program coordinated by a fulltime health education teacher.

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Zusammenfassung Zur Zeit von Robert Koch waren Infektionskrankheiten die Hauptverursacher der Morbidität und Mortalität; heute sind Krankheiten und Todesfälle vorwiegend durch nicht übertragbare Krankheiten verursacht. Charakteristisch für solche Krankheiten ist, dass sie die Konsequenz des eigenen Lebensstiles darstellen z.B. Tabakgebrauch, Fehlernährung. Indem wir in einem listening to nature auf die Signale unseres Körpers achten, können wir die Risikofaktoren für die verschiedenen Arten von Krebskrankheiten aufspüren und identifizieren und ihren Wirkungsmechanismus erforschen. Wir werden Strategien zur Prävention entwickeln können, die diese Risikofaktoren vermindern oder verändern und somit zur Senkung der Inzidenz und der Mortalitätsrate beitragen. Welche Rolle eine Stoffwechsel-Überbelastung im Krankheitsverlauf eines Karzinomes haben kann, zeigt das Beispiel einer übermässig fetthaltigen Ernährung auf die Entwicklung und den Krankheitsverlauf bei Brustkrebs. Zum Verlauf einer Krebskrankheit im allgemeinen lässt sich feststellen, dass jene Risikofaktoren, die mit einer Stoffwechselüberbelastung assoziiert sind, sich stark von solchen unterscheiden, welche Expositionen mit geringen Schadstoffmengen haben. Um in Deutschland den Einfluss der Präventivmedizin zu verstärken und zwar über eine Ausbildung in Ernährungslehre hinausgehend, empfehlen wir, dass a) jede medizinische Ausbildungsstätte eine Abteilung Präventivmedizin mit dem Schwerpunkt Epidemiologie und Gesundheitsförderung hat und dass b) alle Schulen vom ersten Schuljahr an eine umfassende Einführung in ein Gesundheitsprogramm anbieten, welches durch einen Spezialisten koordiniert wird.

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Résumé Alors que du temps de Robert Koch, les maladies infectieuses étaient les principaux déterminants de la morbidité et de la mortalité, la mort et la souffrance sont aujourd'hui causées le plus souvent par des maladies non transmissibles. Ces dernières ont la caractéristique d'être la conséquence de notre propre style de vie, en particulier l'usage du tabac et les excès alimentaires. En étant attentifs à la nature, nous pouvons identifier les facteurs de risque des cancers, explorer leur mécanisme d'action, et mettre en place des stratégies préventives permettant leur réduction ou leur modification: en somme, on peut diminuer l'incidence des maladies et la mortalité. Un exemple du rôle de la surcharge métabolique dans la carcinogenèse est l'effet de la surconsommation de graisses alimentaires sur le développment et la progression du cancer du sein. La pathogenèse générale du cancer, les risques associés avec les surcharges métaboliques sont comparés aux conséquences d'une sous-consommation. Pour augmenter l'impact de la médecine préventive audelà de l'éducation alimentaire en Allemagne, nous recommandons que a) chaque faculté de médecine ait un départment de médecine préventive actif dans les domaines de l'épidémiologie et la promotion de la santé, b) tous les écoliers devraient avoir dès le début de leur scolarité une éducation sanitaire globale, dont l'enseignement serait coordonné par un spécialiste de l'éducation à la santé.

     

Polyhalogenated dibenzo-p-dioxins and dibenzofurans and the immune system

We used a modified version of the popliteal lymph node assay in rats to investigate the immunosuppressive potential of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). In 10 months we conducted 3 experimental series. Animals were treated with single s.c. injections of TCDD and 7 days later human red blood cells (HRBC) were injected s.c. into the right hind footpad of the rat. Another 7 days later, both popliteal lymph nodes were prepared, weighed, the cell number was counted and the quotients (index) of these variables from the treated and the untreated side were determined. The doses applied in three experimental series were 600, 60, 6, 0.6, and 0.06 ng TCDD/kg body wt. In the first experimental series only the three highest doses were tested, in a second experimental series doses of 60, 6, 0.6, 0.06 ng TCDD/kg body wt were applied. Combining the results of these two experimental series, a statistically significant difference was found in the cell number index between the controls and the two highest doses tested (60 and 600 ng/kg body wt;p <0.01). This result was recently published as an abstract (Korte et al. 1990). However, with slight methodological changes in the third series of experiments (doses applied: 600, 60, 6, 0.6, and 0.06 ng TCDD/kg body wt) and using a greater number of animals we could not confirm these preliminary results. No difference was seen in the immune response to the antigen challenge in controls and in any of the treatment groups. We conclude that TCDD does not clearly influence the immune response as observed in the popliteal lymph node assay under our experimental conditions.     

Induction of vascular haemostasis by Nd:YAG laser light in melanin-rich and melanin-free tissue

Haemostasis was effected in vessels of melanin-rich (MR: choroid) and melanin-free (MF: mesentery) rabbit tissue irradiated with a cw-Nd: YAG laser. The following parameters were employed: - pulse duration: 200 ms (MR) and 100ms (MF); focal spot diameter: 200 m (MR) and 80 m (MF); pulse energies: 100–250 mJ (MR) and 0.5-1J (MF); irradiances: 1.6–4.0kWcm^–2 (MR) and 1–2 × 10²kWcm² (MF). In melanin-rich tissue, laser energy is absorbed principally by melanin granules contained within the stromal melanocytes. The heat generated in these structures radiates into the surrounding tissue where it is dissipated. The damage thus incurred by the endothelium of blood vessels encompassed within this field triggers the haemostatic mechanism whereby blood flow is arrested. This effect is realized by the formation of an occluding plug of platelets, which is stabilized by the deposition of fibrin, particularly in capillaries, and to a lesser degree in larger vessels of the vascular lamina. In melanin-free tissue, haemoglobin serves as the primary site of energy absorption, which is thus shifted from the stroma to the vessel lumen. Irradiation of vessels in such tissue leads to thermocoagulation of plasma proteins and consequent stasis of blood flow.     

Estimation of the biophase concentration of noradrenaline at presynaptic α2-adrenoceptors in brain slices

Summary The aim of the present study was to determine the local concentrations of noradrenaline existing at presynaptic ₂-adrenoceptors during electrical pulse train stimulation of brain slices at different frequencies. The experiments are based on the assumption that the concentration of released noradrenaline at the ₂-adrenoceptors exerting a certain autoinhibition should be equal to the concentration of exogenous noradrenaline causing the same inhibition under conditions in which any influence of the released transmitter is excluded. In order to avoid autoinhibition, hippocampus and cortex slices of the rabbit and the rat, prelabelled with [³H]noradrenaline and superfused in presence of an uptake inhibitor, were electrically stimulated using 4 pulses delivered at 100 Hz (POP stimulation). Exogenous noradrenaline diminished the overflow of tritium elicited by POP stimulation in a concentration-dependent manner. In rabbit brain tissues the EC₅₀ value and maximum inhibition of noradrenaline release were found to be approximately 6 nmol/l and more than 95%, respectively, whereas in rat tissues the corresponding values were between 20 and 30 nmol/l and approximately 90%. When electrical stimulation was performed with trains of 36 pulses delivered at 0.1, 0.3 or 3 Hz in absence or presence of an uptake inhibitor, the ₂-adrenoceptor antagonist yohimbine (1 or 10 mol/l) enhanced the evoked tritium overflow in a manner which was dependent on the frequency of stimulation and on blockade of the re-uptake mechanism. The facilitatory effects of yohimbine reflected an extent of autoinhibition which was between 53% (36 pulses/0.1 Hz, no uptake inhibitor) and 85% (36 pulses/3 Hz, uptake inhibitor present) in rabbit and between 16% (36 pulses/0.3 Hz, no uptake inhibitor) and 71% (36 pulses/3 Hz, uptake inhibitor present) in rat brain slices. Accordingly, the corresponding estimated biophase concentrations of noradrenaline were generally higher in rat than in rabbit tissues (they were between 32.5 and 74.5 or 5.1 and 51.6 nmol/l in the presence or absence of an uptake inhibitor, respectively, in the rat, and between 15 and 23.1 or 6.1 and 18.6 nmol/l in the rabbit). The observed frequency dependence of the effect of re-uptake blockade on the calculated biophase concentrations of noradrenaline would be compatible with the idea of a dependence of the effectiveness of the re-uptake mechanism on the firing rate of the neurone in being more effective at lower frequencies. Moreover, the stikingly low biophase concentrations of noradrenaline suggest that also in brain tissue noradrenaline causes lateral inhibition of release as has recently been shown for guinea-pig vas deferens. Send offprint requests to C. Allgaier at the above address     

Stiffness, compliance, elasticity and force generation of outer hair cells.

Isolated outer hair cells (OHCs) were partially sucked into especially designed cell capillaries allowing an experimental reconstitution of the cells' electroanatomy. The experimental approach separated the apical from the basolateral parts of the cells thus forming an artificial scala media and scala tympani. Resistance between both was 121 +/- 42 M omega. A sequence of negative and positive pressures was applied to the basal cell pole allowing "pulling" or "pushing" of the sensory cell investigated. The resulting length changes together with the known pressures allowed the estimation of an actual longitudinal compliance of 354 +/- 35 m/N. Following "pulling" OHCs tended to resume their initial shape after the force had ceased to be effective indicating elastic distortions. The calculated elasticity modulus of OHCs amounted to 6.1 +/- 3.4 kN/m2. From this data an actual longitudinal whole cell stiffness of OHCs of 3 x 10(-3) N/m was calculated. Ultrasound scanning of immobilized OHCs identified the cuticular plate (CP) and a central core between CP and basal cell pole as structures contributing to the cells' acoustic stiffness. Changes of the potential differences between the artificial scala media and scala tympani resulted in active length changes following the command voltage with a slope of delta 1/(1 x U) = 0.055 V-1. Assuming the validity of Hooke's law, the force generation associated with the active length changes can be calculated since the compliance is known.(ABSTRACT TRUNCATED AT 250 WORDS)     

The relationship of blood pressure to a brief measure of anger during routine health screening

A brief questionnaire (12 items) was developed to assess aspects of anger that could be expeditiously obtained during health screenings where medical students and residents can acquire valuable research and clinical experience simultaneously. Blood pressures were measured immediately upon sitting and after 3 minutes in 179 subjects who attended a health fair in Nashville. The questionnaire was administered after both blood pressure measurements were acquired. Scores on the measure of anger correlated significantly (P = .0009) with resting systolic blood pressure (SBP) in both blacks and whites while a measure of "John Henryism" showed no correlation with blood pressure in either group (P = .81). The findings are consistent with the literature in supporting a connection between anger and blood pressure but do not support the relationship between John Henryism and blood pressure.     

Child psychiatrists' views of DSM-III-R: a survey of usage and opinions

The DSM-IV Child Psychiatry Work Group surveyed 460 child psychiatrists about their use of DSM-III-R and their reactions to specific proposed nosological revisions for DSM-IV. This paper presents the responses of the sample as a whole and of respondent subgroups with different theoretical, practice, and training characteristics. The survey indicates that DSM-III and DSM-III-R are widely used and generally accepted by child psychiatrists. Ninety-eight percent of respondents believe a criterion-based diagnostic system is useful, and 65% consider DSM-III-R to be an improvement over DSM-III. Depending on the diagnosis 47% to 66% of the respondents reported that they generally assess all applicable criteria and 28% to 49% often refer to the manual before assigning a diagnosis. A majority of respondents supported proposals for several new diagnostic subtypes. Ninety-three percent of respondents indicated that "adequacy of family support" was very valuable for treatment planning or estimating prognosis. Fifty-five percent of respondents admitted to diagnosing adjustment disorders in order to avoid the stigma associated with other disorders. Child psychiatrists who are psychodynamically oriented or practicing in an office-based setting or out of training for more than 10 years tend to use the DSM-III-R less rigorously.