Early onset of regional intestinal ischemia can be detected with carbon dioxide tension measurement inside the peritoneal cavity.

UNLABELLED: Methods for detecting regional gastrointestinal ischemia are rare. An early detection of ischemia in the stomach or ileum can be achieved by the continuous intramucosal PCO(2) (PiCO(2)) measurement in the region. However, physiological consideration suggests that the placement of a fiberoptic CO(2) sensor in the peritoneal cavity should yield comparable results. We tested the hypothesis that a continuous PCO(2) measurement in the peritoneal cavity allows the early detection of regional intestinal ischemia. A laparotomy was performed in six pigs (54.7 +/- 3.7 kg) with a tourniquet being placed around respective vessels to allow complete ischemia of a 2. 75-m part of the ileum. A fiberoptic CO(2) sensor (PiCO(2)-ileum) was placed intraluminally in the ileum outside this segment. A second fiberoptic CO(2) sensor to measure intraperitoneal PCO(2) (i. p.-PCO(2)) was placed inside the peritoneal cavity in close vicinity to the ischemic gut segment. Gastric PiCO(2) was determined by using air tonometry. After baseline measurements, ileal ischemia was induced for 180 min followed by a 30-min reperfusion period. Statistics were performed with a Friedman test followed by Wilcoxon Analysis with P: < 0.01 considered significant. With the onset of local ileal ischemia, a sudden increase in i.p.-PCO(2) from 48.9 (45. 0-51.5) mm Hg (mean and 25-75 percentiles) to 94.3 (87.9-95.5; P: < 0.01) mm Hg was observed. Gastric PiCO(2) (49.0 [47.5-51.0]/53.5 [49. 0-54.0] mm Hg), and ileal PiCO(2) (56.4 [44.6-57.0]/54.3 [46.1-57.8] mm Hg) did not change. With reperfusion, the i.p.-PCO(2) decreased but stayed above baseline values. IMPLICATIONS: Unless systemic changes are induced, regional intestinal perfusion deficits cannot be detected with a PCO(2) measurement in the gastric lumen. In pigs, an occlusion of blood flow to an isolated gut segment resulted in a significant increase in intraperitoneal CO(2) tension. Thus, the measurement of intraperitoneal PCO(2) could allow the early detection of regional intestinal ischemia.

Bactericidal effect of extracorporeal shock waves on Staphylococcus aureus.

Despite considerable knowledge about the effects of shock waves on eukaryotic soft tissues, no data are available concerning their effect on prokaryotic micro-organisms. In vitro studies on the bactericidal effect of extracorporeal shock waves on staphylococci were performed with energy levels that are standard for the disintegration of calculi. Suspensions containing 10(4)-10(5) cfu of Staphylococcus aureus/ml were sealed in plastic tubes and exposed to shock waves, resulting in a mean decrease of 3.1 log(10). Whereas impulse rates of > or =350 resulted in a decrease of cfu/ml equalling the detection limit, lower numbers of impulses did not result in an appreciable bactericidal effect. The bactericidal effect of extracorporeal shock waves might provide the basis for the development of novel therapeutic strategies for bacterial infections.

Dose-dependent induction of transforming growth factor beta (TGF-beta) in the lung tissue of fibrosis-prone mice after thoracic irradiation.

PURPOSE: The lung is the major dose-limiting organ for radiotherapy of cancer in the thoracic region. The pathogenesis of radiation-induced lung injury at the molecular level is still unclear. Immediate cellular damage after irradiation is supposed to result in cytokine-mediated multicellular interactions with induction and progression of fibrotic tissue reactions. The purpose of this investigation was to evaluate the acute and long-term effects of radiation on the gene expression of transforming growth factor beta (TGF-beta) in a model of lung injury using fibrosis-sensitive C57BL/6 mice. METHODS AND MATERIALS: The thoraces of C57BL/6 mice were irradiated with 6 and 12 Gy, respectively. Treated and sham-irradiated control mice were sacrificed at times corresponding to the latent period (1, 3, 6, 12, 24, 48, 72 hours and 1 week postirradiation), the pneumonic phase (2, 4, 8, and 16 weeks postirradiation), and the beginning of the fibrotic phase (24 weeks postirradiation). The lung tissue from three different mice per dosage and time point was analyzed by a combination of polymerase chain reaction (PCR), immunohistochemistry, and light microscopy. The mRNA expression of TGF-beta was quantified by competitive reverse transcriptase/polymerase chain reaction (RT-PCR); the cellular origin of the TGF-beta protein was identified by immunohistochemical staining (alkaline phosphatase-anti-alkaline phosphatase [APAAP]). The cytokine expression on mRNA and protein level was correlated with the histopathological alterations. RESULTS: Following thoracic irradiation with a single dose of 12 Gy, radiation-induced TGF-beta release in lung tissue was appreciable already within the first hours (1, 3, and 6 hours postirradiation) and reached a significant increase after 12 hours; subsequently (48 hours, 72 hours, and 1 week postirradiation) the TGF-beta expression declined to basal levels. At the beginning of the pneumonic phase, irradiation-mediated stimulation of TGF-beta release reached maximal values at 2 and 4 weeks. The elevated levels of TGF-beta mRNA during the latent phase have been found to correlate with immunohistochemical staining of alveolar macrophages. The most striking increase in TGF-beta immunoreactivity was seen during the acute phase of pneumonitis. Throughout this observation period, type II pneumocytes and fibroblasts (apart from inflammatory cells) served as important sources of TGF-beta expression. Increased TGF-beta expression was detected prominently in regions of histopathologic radiation injury. After exposure to a single radiation dose of 6 Gy, the lung tissue revealed only a minor radiation-mediated TGF-beta mRNA response. The modest upregulation ranged from 6 hours to 48 hours after irradiation. Corresponding to the only minor histopathologic changes after thoracic irradiation with 6 Gy, measurement of TGF-beta mRNA levels during the later time points revealed no significant alterations in comparison to untreated control mice. CONCLUSIONS: This study demonstrates an acute and long-lasting increase in the expression of TGF-beta in lung tissue following thoracic irradiation with 12 Gy. The predominant localization of TGF-beta in areas of inflammatory cell infiltrates and fibrosis suggests involvement of this cytokine in the pathogenesis of radiation-induced pulmonal fibrosis. Further studies should be performed to explore the role of other cytokines in the development of radiation injury. An improved understanding of the underlying mechanisms of pulmonary fibrosis may eventually lead to modulatory intervention at the molecular level to modify the fibrotic process.

Estradiol and high-dose dihydrotestosterone treatment causes changes in cynomolgus monkey prostate volume and histology identical to those caused by testosterone alone.

To evaluate the effects of testosterone (T), dihydrotestosterone (DHT), and estradiol (E2) on the regulation of prostate growth and tissue composition, the following study was conducted in a nonhuman primate model. Fifteen adult, long-term castrated cynomolgus monkeys were randomly assigned to receive implants filled with T (0.19 +/- 0.01 g), DHT alone (0.21 +/- 0.01 g), or (99%) DHT + (1%) E2 (0.21 +/- 0.01 g). Prior to and at 4-week intervals during the treatment phase of 252 days, prostate volumes (PV), body weight, ejaculate weight, hormone levels (of T, DHT, and E2), and red blood cell count were measured. Five adult, intact monkeys served as controls for prostate volume and histology. At the end of the study, histological analysis of an ultrasound-guided prostate biopsy was performed. T levels increased significantly in the T group compared with baseline (P < 0.01) and with the DHT and DHT + E2 groups (P < 0.05). Both groups receiving DHT showed higher DHT levels than did animals in the T group (P < 0.001). E2 levels in all groups increased over time (P < 0.05), although significant differences (P < 0.01) could only be detected between the DHT + E2 and the DHT group. Prostate volume in all groups increased (at baseline: T = 1.03 +/- 0.12 ml, DHT = 1.08 +/- 0.15 ml, DHT + E2 = 1.13 +/- 0.09; at day 252: T = 5.83 +/- 1.00, DHT = 4.72 +/- 0.9, DHT + E2 = 5.05 +/- 0.62) over time (P < 0.001), whereas no differences could be detected between the groups. Prostate biopsy could be performed successfully in 15 out of 20 monkeys. Prostate tissue evaluation between the treatment groups and the evaluated intact monkeys revealed no differences in the status of secretory epithelia, nuclear chromatin, excretory vacuoles, interstitial stroma, smooth muscles, and total functional status, whereas the prostate of a long-term castrated monkey showed severe atrophy. Thus, both androgens fully restored prostate volume and ejaculatory function. Highly supraphysiological DHT serum levels are not associated with abnormal volumetric or histological changes of the prostate. Comparing the DHT group with the DHT + E2 group, an additional stimulatory effect of normal or slightly elevated estrogens on the prostate cannot be found in the presence of highly supraphysiological DHT levels.

Animal model of experimentally induced ectopic enchondral ossification in nude mice with xenograft of porcine epiphyseal cartilage.

In a specific animal model the induction of heterologous enchondral ossification was examined in long term follow-up. Physiologically normal and devitalized frozen porcine epiphyseal cartilage as a control group were transplanted as s.c. xenograft into athymic nude mice (nu/nu). 15 weeks after transplantation the porcine growth plate cartilage showed the development of viable cartilage tissue in the recipients, further differentiating to juvenile long bone with epiphysis, diaphysis and growth plate. Porcine growth plate cartilage increased s.c. in the recipient nude mice, showing enchondral ossification without any physiological load, and finally an unexpected development towards complete juvenile long bone.

Continuous intramucosal PCO2 measurement allows the early detection of intestinal malperfusion.

OBJECTIVES: The intestinal metabolic and histologic changes that occur in the gastrointestinal tract with ischemia and that form the basis of intramucosal pH and PCO2 alterations have not been well established. Recent evidence suggests that apart from technical problems with gastric tonometry, some methodologic misconceptions in the interpretation of intramucosal pH and PCO2 exist. The present study was designed to demonstrate the effects of impaired mesenteric perfusion with specific consideration to the induced intramucosal PCO2 changes using a new technique, the continuous fiberoptic CO2 sensor, and a new concept of interpretation. DESIGN: Randomized, controlled intervention trial. SETTING: University animal laboratory. SUBJECTS: Twelve anesthetized female pigs, weighing 67+/-6 kg. INTERVENTIONS: The pigs were assigned to control and stenosis groups. In the stenosis group, blood flow in the superior mesenteric artery was reduced by 70% from baseline for 180 mins, followed by 120 mins of reperfusion. Serum lactate concentration, pH, PCO2, PO2, and bicarbonate concentration (cHCO3-) were determined in arterial, superior mesenteric venous, portal venous, hepatic venous, and pulmonary arterial blood. In the lumen of the ileum, intramucosal PCO2 was continuously determined by a fiberoptic CO2 sensor. At the end of the experiment, the gut was examined for histologic changes. MEASUREMENTS AND MAIN RESULTS: During mesenterial hypoperfusion, a sudden and significant increase in intramucosal PCO2 was observed. This increase was paralleled by increases in superior mesenteric venous PCO2 and portal venous PCO2 (p < .05) and a concomitant decrease in intramucosal pH, superior mesenteric venous pH, and portal venous pH. Arterial and mixed venous PCO2 and pH did not change. cHCO3- did not change in local or systemic blood samples. CONCLUSIONS: Compromised mesenteric blood flow causes significant metabolic and histologic changes. These local changes could not be detected by arterial or mixed venous lactate concentrations, pH, and PCO2 determinations. Under closed-system conditions, mesenteric CO2 accumulation causes an impairment of the CO2-HCO3- buffer, resulting in an unchanged cHCO3-. With impaired mesenteric perfusion, only intramucosal PCO2 alterations occur and an intramucosal pH calculation based on systemic cHCO3-changes is not necessarily correct. Therefore, the only parameter of importance is the intraluminal measurement of intramucosal PCO2 that can reflect isolated mesenteric changes. Thus, we recommended abolishing the terms "intramucosal pH measurement" and "gastric tonometry" and propose using the definition "intramucosal PCO2 measurement."

The heart muscle's putative "secondary structure'. Functional implications of a band-like anisotropy.

Opinions are divided as to whether the rope-like secondary structure, which Torrent-Guasp dissected out of the myocardial body by the blunt unwinding technique (BUT) reveals some kind of functional compartmentation of the heart muscle. The myocardial fibres are aligned parallel to the fibre disruption (cleavage) plane, along which the band has been prepared but they are not necessarily aligned parallel to the long axis of the band. Inconsistencies in the myocardial rope model arise from the obligatory zones of transmural inflection, which are obvious in the base and the apex of both ventricles. They are, however, merely discernible in the midzone of the left ventricular cone. The investigator experienced in BUT knows that the cleavage plane is not unique. We doubt the assumption that the rope structure is the predominant stress transmission pathway, because the fibre strand peel-off technique (SPOT) delivers irregular fibre disruption planes which are definitely different from those which Torrent-Guasp prepares. The rope-like fibre arrangement could be just a redundant structure, a remnant of past developmental steps without, however, any functional implication to the human heart. On the other hand, peeling-off fibre strands from the ventricular wall produces deeply perforating, i.e., oblique transmurally grooved surfaces. Putative functions of force transmission in an oblique transmural direction are (1) ventricular dilation as a function of the variable inclination angle with respect to the epicardial surface, (2) monitoring of ventricular wall stress and ventricular size and (3) segmental stiffening which could serve other dependent segments as a punctum fixum.

The heart's fibre alignment assessed by comparing two digitizing systems. Methodological investigation into the inclination angle towards wall thickness.

Myocardial contractile pathways which are not aligned strictly parallel to the heart's epicardial surface, give rise to forces which also act in the ventricular dilating direction. We developed a method which allows us to assess any fibre orientation in the three-dimensional myocardial weave. Decollagenized hearts were prepared by peeling-off fibre strands, following their main fibre orientation down to near the endocardium. In the subepicardium the strands followed a course more or less parallel to the epicardium, whereas from the mid-wall on they tended to dive progressively deeper into the wall. The preparation displays more or less rugged surfaces rather than smooth layers. The grooves and crests on the exposed surfaces were sequentially digitized by two methods: (1) Using a magnet tablet (3 Draw Digitizer System, Polhemus, Cochester VTO 5446, USA) on a dilated pig heart we manually followed the crests using a stylus, handling each groove and crest as an individual contractile pathway. (2) A constricted cow heart was digitized using a contact-free optical system (opto TOP, Dr. Breuckmann, Meersburg, Germany), which is based on the principle of imaging triangulation. Using specially developed software the inclination angles of selected crests and grooves with respect to the epicardial surface were calculated. The two digitizing methods yield comparable results. We found a depth- and side-specific weave component inclined to the epi-endocardial direction. This oblique netting component was more pronounced in the inner 1/3 of the wall than in the subepicardium. The inclination angle probably increases with increasing wall thickness during the ejection period. Manual digitizing is an easy and fast method which delivers consistent results comparable with those obtained by the cumbersome high resolution optical method. The rationales for the assessment of transmural fibre inclination are (1) the putative existence of dilating forces inherent in the myocardial weave and (2) the possible overproportional increase in the oblique transmural weave component during myocardial hypertrophy, which would entail a reduction in efficiency of ventricular performance in terms of haemodynamic work.

The assessment of intramural stress alignment on the beating heart in situ using micro-ergometry: functional implications.

The main local stress transmission pathways in the left ventricular base, midportion and apex in up to seven layers have been assessed in normal dog and porcine hearts, in hypertrophied dog hearts, and in three pig hearts having undergone a temporary left ventricular outflow stricture. The rotational sensitivity of needle force probes was used to determine the focal surface-parallel direction of the myocardial tension vector. In all places investigated the orientation of the force transmission pathways differs slightly from the morphologically determined fibre alignment. Vector rotation upon an axis normal to the epicardial surface is definitely tempered as compared to fibre rotation. Alterations in the force transmission pathways assessed in hypertrophied dog hearts by micro-ergometry qualitatively confirm structural remodelling in so far as an irregularity in the transmural rotation of the main stress vector was found. The measured disparities between the alignment of the myocardial fibre weave and the direction of stress transmission both in the normal and the diseased heart is widely individual, and hence, scattering of the data is marked. However, it must also be called into consideration that the measured orientation of force vectors is that at the moment of highest developed force, only. Further investigations will elucidate if discrepancies between that force vector and morphology are less pronounced when the vector is averaged over the entire heart cycle.

Fat infiltration in liver of rats induced by different dietary plant oils: high oleic-, medium oleic- and high petroselinic acid-oils.

Beneficial effects on health parameters by ingestion of plant oils having high levels of monounsaturated fatty acids such as oleic (cis-9-octadecenoic) acid have been described in several studies. Recently, we have shown that feeding of coriander oil containing high proportions of a positional isomer of oleic acid, i.e. petroselinic (cis-6-octadecenoic) acid, led to significantly decreasing proportions of arachidonic (all cis-5,8,11,14-eicosatetraenoic) acid in the cellular lipids. Here, we report histopathological findings in male Wistar rats fed isocaloric diets containing 2% corn oil and 12% (w/w), each, of different plant oils (high-oleic and conventional sunflower oil, olive oil, rapeseed oil as well as coriander oil) containing varying levels of monounsaturated fatty acids, i.e. oleic or petroselinic acids. One group of animals was fed a standard diet containing 4% (w/w) of fat as control. Liver, heart, aorta, stomach, and spleen were anatomically and histologically examined. Livers of animals from all the groups that had received high-fat diets-except the coriander oil group-showed moderate non-degenerative fat infiltrations of the hepatocytes beginning in the periportal fields. Marked to severe fat infiltration was observed in hepatocytes of animals fed coriander oil. In this experimental group the livers were found to contain fatty cysts in addition to hepatocytes with mixed-size lipid vesicles. Moreover, enlarged nuclei were observed in numerous hepatocytes without fat infiltration. Fat infiltration was not observed in livers of animals fed a rat standard diet. In the cells of all other organs and tissues studied, in particular heart and aorta, neither non-degenerative fat infiltrations nor other degenerative changes were observed for any group. Our results show that feeding of fat-rich diets containing varying proportions of C18 cis-monoenoic fatty acids induced different histopathological alterations in the livers of rats, depending on position of the double bond. Plant oils containing varying proportions of oleic acid lead exclusively to moderate fat infiltration in the hepatocytes, whereas in the animals fed high-petroselinic coriander oil degenerative alterations (fatty cysts) as well as -in several cases-enlarged nuclei were found that are likely due to a non-specific stimulation of the hepatocytes resulting from the cell degeneration observed.

Petroselinic acid from dietary triacylglycerols reduces the concentration of arachidonic acid in tissue lipids of rats.

Studies in vitro have revealed that triacylglycerols containing petroselinoyl [18:1(n-12)] moieties are hydrolyzed by pancreatic lipase at much lower rates than other triacylglycerols. To assess the lipolysis and absorption in vivo of such unusual triacylglycerols, diets containing 120 g seed oil triacylglycerols of coriander (Coriandrum sativum) per kg diet at a level of 72 g 18:1(n-12) moieties/100 g oil were fed to a group of weaned male Wistar rats without restriction for a period of 10 wk. For comparison, groups of rats were fed similar isocaloric diets containing plant oil triacylglycerols with various levels of oleoyl [18:1(n-9)] moieties, e.g., high oleic sunflower seed oil [75 g 18:1(n-9)/100 g oil], olive oil [(66 g 18:1(n-9)/100 g oil], medium oleic rapeseed oil [54 g 18:1(n-9)/100 g oil] and conventional high linoleic sunflower seed oil [25 g 18:1(n-9)/100 g oil]. All diets were supplemented with 20 g corn oil/kg diet. Consumption of coriander oil, compared with the other oils, led to significantly greater liver weights. No significant differences were observed among the groups fed various levels of oleic acid in body weight, the weights of heart, liver, kidneys, spleen or testes, lipid content of heart, or total cholesterol, HDL cholesterol and triacylglycerol concentrations of blood plasma. Ingestion of coriander oil led to incorporation of 18:1(n-12) into heart, liver and blood lipids and to a significant reduction in the concentration of arachidonic acid in the lipids of heart, liver and blood with a concomitant increase in the concentration of linoleic acid compared with results for the other groups.(ABSTRACT TRUNCATED AT 250 WORDS)

3 beta-Chlorosteroids: artefacts and possible contaminants in food and feed--toxicological effects in mice.

3 beta-Chlorosteroids, such as cholesteryl beta-chloride and sitosteryl beta-chloride, are formed during the production of protein hydrolysates, which are useful flavour enhancers. These chlorinated steroids may also attract attention as environmental contaminants if they are released from liquid crystal display devices. The effects of orally administered 3 beta-chlorosteroids were tested in female NMRI mice. The animals were fed cholesteryl beta-chloride or sitosteryl beta-chloride at doses of 1 mg and 10 mg/animal/day, that is, 33 mg and 330 mg/body weight/day, over a period of 3 months. Feed intake, body weight and organ weights of the animals, as well as concentration of 3 beta-chlorosteroids in faeces and various organs and tissues showed that cholesteryl beta-chloride and sitosteryl beta-chloride are not acutely toxic compounds. However, chronic toxicity cannot be excluded because small amounts of 3 beta-chlorosteroids, in particular cholesteryl beta-chloride, were absorbed by the intestinal tract and accumulated in adipose tissue. Histopathological examination of sections of organs and tissues showed no indication of irreversible cell damage in the stomach, duodenum, liver, kidneys and spleen caused by the chlorinated steroids.

The difficult access to morphology of the heart: clinical implications.

The literature on the morphology of the heart is reviewed within the context of recent histological findings. There is strong evidence for a dualistic myocardial function, whereby both ventricular constricting and expanding forces are supposed to act synchronously although with variable effect over the heart cycle.The morphological basis of this dualistic myocardial function is the contorted rope-like structure worn into the bulk of the heart muscle. Opinions are divided about the invasiveness of blunt preparation on the heat denatured heart by which the fascicular architecture is carved out of the muscle. Histology confirms the existence of a fascicular substructure. It results from an inhomogeneous repartition of myocardial fibre branchings and the arrangement of the delicate connective tissue netting by which myocardial strands are bundled and wrapped. One important feature of the fascicular structure of the heart muscle is an oblique transmurally arranged element which yields a force vector opposing systolic wall thickening. This structural element which acts in the direction of ventricular dilation probably gains pathological import in some cases of architectural remodelling, namely in myocardial fibrosis and hypertrophy.

[Comparative study of the detection of E. coli after time in seawater with partially modified standard media]. / Vergleichende Untersuchung zum Nachweis von E. coli nach Aufenthalt in Meerwasser mit partiell modifizierten Standardmedien.

Fecal coliform bacteria (E. coli) are the most important parameter when monitoring the hygienic quality of bathing water according to EC guidelines. Among other things the number of E. coli is clearly dependent on the length of exposure of the bacteria to marine water as well as the media used to establish the number. In a seven-day salt water stress experiment the best rate of recultivation was achieved on average with DEV lactose peptone broth. The Brila-MUG medium produced a slightly lower rate of recultivation and the fluorocult-lauryl-sulfate-broth the lowest rate of recultivation. After a shorter exposure of bacteria to marine water conditions (up to 24 h) the DEV-lactose-broth produced slightly lower rates of recultivation. An alteration of the standard components of the media did not lead to an improvement in the rate of recultivation.

[Direct radiographic magnification in bone infections]. / Direktradiographische Vergrösserung bei Knocheninfektionen.

An experimental model of bacterial osteomyelitis was used to investigate the correlation of direct radiographic magnification and histopathologic changes in the femora of rabbits. The histopathologic changes demonstrated a severe chronic state of osteomyelitis. The extent of radiographic changes was more clearly recognizable with direct radiological enlargement (up to 15-fold) than on normal radiographs: this applied to destruction of marrow and cortical bone, formation of sequestra, and (frequently) extraosseous extension. Histopathologic findings were in agreement with the changes revealed by direct radiographic enlargement.

Microprobe analyses of the potassium-calcium distribution relationship in predentine.

Apex regions of continuously growing incisors of Wistar rats were quickly dissected, shock-frozen in liquid nitrogen-cooled propane, freeze-dried at -80 degrees C and infiltrated with Spurr's resin. 400nm thick dry sections were cut with a diamond knife on an ultramicrotome. Relatively flat sections were transferred with an eye lash onto collodium coated aluminum grids. They were flattened with a glass stick and by placing another collodium coated aluminum grid just on top of the first one, exerting a uniform pressure. After carbon coating the sections were observed using the backscattered and secondary electron signals in a scanning microscope. The predentine was analyzed for calcium and potassium with an energy dispersive x-ray analysis system. The x-ray spectra revealed in the predentine regions with beginning dentine formation, near the apex, an uneven K-distribution with very low as well as more prominent x-ray peaks. The K peaks were always lower than those of calcium. In areas with advanced dentine formation, prominent K-peaks were always observed. They were normally higher than the Ca-peaks up to a distance of 5-10 microns from the dentine border. Closer to the dentine border the K concentration decreased while the Ca-peak increased. This might indicate that (besides Na) K is used to balance the negative charges of the macromolecules till K is replaced by Ca at the onset of apatite crystal formation.

Radiofrequency coagulation of ventricular myocardium: improved prediction of lesion size by monitoring catheter tip temperature.

To assess the importance of voltage, current, impedance and catheter tip temperature for the prediction of the size of tissue injury induced by transcatheter radiofrequency application, radiofrequency pulses (500 kHz) were delivered both in vitro and in vivo to isolated ventricular preparations and the intact canine heart, respectively. Radiofrequency coagulations were performed using unipolar electrode configuration. Besides measurements of current and voltage which were used to calculate the delivered power and tissue impedance, the catheter tip temperature was monitored during each application using specially designed 6F USCI catheters with a built-in nickel/chromium-nickel thermoelement. Lesion dimensions were measured and the correlation between lesion volume and delivered radiofrequency energy, maximum changes in catheter tip temperature and the integral of the temperature curve were calculated. First, in a pilot in vitro investigation, 50 radiofrequency coagulations (3.2 W-22.4 W, pulse duration 10 s) were performed in ventricular preparations from freshly excised dog hearts. The correlation between applied radiofrequency energy and lesion volume was 0.87; the correlation between maximal catheter tip temperature and lesion volume was 0.82; the correlation between temperature integral and lesion volume was 0.9. In the intact dog heart, 44 radiofrequency pulses were delivered to the left and right ventricular endocardium in 12 anaesthetized dogs (exposure time: 10 s). Delivered power ranged between 5.6 W and 24.6 W; tissue impedance varied between 92 omega and 364 omega; lesion volume measured 0-273 mm3; developed peak temperatures ranged from 16.25 degrees C to 196 degrees C. The calculated integral beneath temperature curves measured 126-1971 degrees C.s. The correlation between applied radiofrequency energy and lesion volume was 0.32; the correlation between maximal catheter tip temperature and lesion volume was 0.61. Temperature integral correlated best with the assessed volume of myocardial necrosis (r = 0.7). No significant arrhythmogenic or haemodynamic side-effects were observed. Macroscopic examination showed a central depression surrounded by a zone of homogeneous coagulation. Vaporization and crater formation up to a depth of 4 mm were observed following three radiofrequency discharges. In two of these cases, rapid changes and oscillation of catheter tip temperature were observed. Thus, monitoring of catheter tip temperature during radiofrequency energy application improves the prediction of lesion size. In addition, temperature monitoring might improve the safety of the procedure with respect to the risk of perforation.

[Thorotrastosis--a rare disease picture in internal medicine]. / Die Thorotrastose--ein seltenes Krankheitsbild in der Inneren Medizin.

The report deals with the late effects following administration of thorotrast in a 63-year-old patient: liver cirrhosis developed after application of thorotrast 25 years ago. The clinical findings are described and attention is drawn to the relevance of this disease at present time. The authors refer to the significance of the routine X-ray diagnosis and of the CT for finding a diagnosis with thorotrastosis.

The protective effect of Allium sativum and crataegus on isoprenaline-induced tissue necroses in rats.

Possible protective effects of Allium sativum and Crataegus--alone and in combination--on isoprenaline (isoproterenol)-induced heart, liver and pancreas damage were studied using rats as test animals. Pretreatment with Allium sativum alone, or in combination with Crataegus, resulted in protective effects on isoprenaline-induced damage of heart, liver, and pancreas. These effects proved to be dose-dependent. The following parameters were used to evaluate the protective effect: Clinical signs, qualitative histological and histoenzymatical findings, as well as quantitative microphotometric determination of enzymatic activities of succinate dehydrogenase, NADH-NBT reductase, acid phosphatase and glucose-6-phosphate dehydrogenase in cardiac, hepatic and pancreatic tissues. The underlying mechanisms are discussed. The results suggest that Allium sativum, resp. Allium sativum plus Crataegus exert a pronounced protective effect.

Strontium as a tracer to study the transport of calcium in the epiphyseal growth plate (electronprobe microanalysis).

At the mineralization front of the epiphyseal growth plate large quantities of calcium (Ca) are necessary to form the mineral (a Ca-phosphate). It is an unsolved problem, whether Ca is transported through the cells of the growth plate cartilage or extracellularly. Electronprobe microanalysis (EPMA) allows the quantitative, morphologically correlated analysis of elements. EPMA can discriminate only different elements. To investigate the transport of Ca, Strontium (Sr) is a very good tracer, as it resembles Ca in many biological reactions. Our results demonstrate that the transport of Sr from the blood into the growth plate and through the growth plate needs only one or a few minutes. The measured intracellular Sr and Ca concentrations are much lower than the extracellular ones, while the intracellular Sr/Ca ratio is not or only a little bit lower than the extracellular one. It must be concluded, that significant amounts of Ca are neither transported through nor accumulated in the cells of the growth plate cartilage. The main transport is an extracellular diffusion. Using Sr as a tracer for Ca new results on the behaviour of Ca could be received.