Effect of propentofylline (HWA 285) on focal ischemia in rats: effect of treatment and posttreatment duration on infarct size

BACKGROUND AND PUROSEe: in this study we tested the potentially neuroprotective properties of propentofylline in a model of focal ischemia with long-term, repeated treatment.

METHODS

37 male Wistar rats (280-300 g) underwent permanent occlusion of the middle cerebral artery (MCA). Infusion was started 30 min after occlusion of the MCA over a period of 2 h with a dosage of 0.01 mg/kg body weight. Immediately after the termination of infusion repetitive intraperitoneal injections were started. Animals were assigned to four groups: continuous treatment for a period of 12 h with 24-h survival (group A, n=9) or 48-h survival (group B, n=10), continuous treatment for a period of 48 h with 48-h survival (group C, n=9) and placebo (group D, n=9). Infarct size was calculated from brain slices stained with 2,3,5-triphenyltetrazolium chloride.

RESULTS

the infarct size was significantly reduced in group C (treatment for 48 h) (163.9+/-30.5 mm(3)) compared to the placebo group (297.4+/-17. 7 mm(3)). No effect on infarct size was observed in group A (196. 8+/-37.3 mm(3)) and group B (239.6+/-42.9 mm(3)) compared to placebo.

CONCLUSION

continuous i.p. injections of propentofylline over a period of 48 h significantly reduces infarct size in an animal model of focal cerebral ischemia. With shorter periods of continuous administration of the drug and delayed postmortem analysis, reductions in the infarct size did not reach a level of significance. These data show the importance of continuous long-term administration after ischemic stroke in clinical trials to achieve the beneficial effects of neuroprotection by propentofylline.

Internalization of extraintestinal Escherichia coli O18 strains by epithelial cells is modulated by EGF, insulin, and effectors of transmembrane signal transduction

Adhesion to and internalization into host cells is an essential step in the pathogenesis of various bacterial infections. Here we investigated the effects of growth factors on the internalization of Escherichia coli O18 strains isolated from patients with urinary tract infection (UTI) by human epithelial cells. A dramatic increase in the uptake of Escherichia coli was observed after treatment of epithelial cells with epidermal growth factor (EGF) and to a lower extent with insulin. EGF-dependent internalization can be suppressed by tyrosine kinase inhibitors suggesting an involvement of the receptor tyrosine kinases in the regulation of the endocytotic process. Inhibitors of phospholipase A2, lipoxygenase, and cyclooxygenase significantly decreased internalization of bacteria induced by EGF. Finally, the specific inhibitor of PI 3-kinases Wortmannin was shown to suppress completely the EGF-independent internalization. The data of this analysis indicate the involvement of several signaling paths in bacterial internalization of uropathogenic Escherichia coli O18 strains and contribute to the comprehension of the pathogenesis of recurrent UTI.

Notes from the industry: new solution for the integration of the computer tomograph into the OR environment

Seconds can be crucial in surgery. Maquet AG in Germany has developed a new integrated surgical work-station for faster, safer and more gentle therapeutic procedures. Awigs, the advanced workplace for image-guided surgery, is a unique unit that integrates diagnostics, surgery and patient-monitoring without the risk of moving the patient from their bed.

Dermal route in systemic exposure

To evaluate risk from dermal exposure, the amount of material on the skin must first be measured. The potential for dermal uptake must then be assessed for the potential health effects from systemic exposure. No standard methods exist for studying these processes, and published data are not comparable because of the different techniques used. Future validated methodology should provide a sound scientific basis for risk assessment. Methods for measuring skin and surface contamination will require development of reference contaminated surfaces and skin as part of quality control procedures. Biological monitoring is a valuable tool in the assessment of dermal absorption, in contributing to the validation of in vitro techniques, and in risk assessment and management. It will be necessary to conduct detailed investigations to support risk assessment for dermal exposure. Ultimately, predictive models will be established for exposure and for dermal absorption to support a generic approach and allow risk assessment strategies appropriate to actual workplace situations.

One-step polymerase chain reaction-based typing of Helicobacter pylori vacA gene: association with gastric histopathology

Heterogeneity of the Helicobacter pylori vacA gene may be associated with bacterial virulence and presentation. In this study, the possible correlation between vacA genotypes and gastric histopathology was investigated. Using a modified one-step polymerase chain reaction (PCR)-based method, 122 of 131 H. pylori isolates obtained from 63 of 67 patients from Germany were classified into distinct vacA genotypes according to their signal sequence (s1 or s2) and their midregion alleles (m1 or m2). A possible subtype of ml, now alluded to as m3, was identified in one-third of the isolates. Signal sequence s1 was significantly associated with higher H. pylori density but not with gastric inflammation parameters as compared with s2. Compared with m2, ml initially appeared to correlate with higher mononuclear cell scores in corpus, although not with H. pylori density. Upon differentiation between ml and m3, however, only the latter was associated with the high cell scores. Moreover, m3 also correlated with a higher antral H. pylori density. Positive cagA status correlated significantly with vacA signal sequence s1, and higher gastric mononuclear cell scores and corpus neutrophil score. H. pylori density was always associated with enhanced gastric neutrophil and corpus mononuclear cell scores. These data indicate a significant association of specific vacA genotypes with enhanced bacterial density and gastric inflammation. PCR-based identification of the respective alleles can now easily be performed in the diagnostic laboratory using a one-step PCR assay.

Comparison of the Ca2 + currents induced by expression of three cloned alpha1 subunits, alpha1G, alpha1H and alpha1I, of low-voltage-activated T-type Ca2 + channels

Expression of rat alpha1G, human alpha1H and rat alpha1I subunits of voltage-activated Ca2 + channels in HEK-293 cells yields robust Ca2 + inward currents with 1.25 mM Ca2 + as the charge carrier. Both similarities and marked differences are found between their biophysical properties. Currents induced by expression of alpha1G show the fastest activation and inactivation kinetics. The alpha1H and alpha1I currents activate and inactivate up to 1.5- and 5-fold slower, respectively. No differences in the voltage dependence of steady state inactivation are detected. Currents induced by expression of alpha1G and alpha1H deactivate with time constants of up to 6 ms at a test potential of - 80 mV, but currents induced by alpha1I deactivate about three-fold faster. Recovery from short-term inactivation is more than three-fold slower for currents induced by alpha1H and alpha1I in comparison to alpha1G. In contrast to these characteristics, reactivation after long-term inactivation was fastest for currents arising from expression of alpha1I and slowest in cells expressing alpha1H calcium channels. The calcium inward current induced by expression of alpha1I is increased by positive prepulses while currents induced by alpha1H and alpha1G show little ( < 5%) or no facilitation. The data thus provide a characteristic fingerprint of each channel's activity, which may allow correlation of the alpha1G, alpha1H and alpha1I induced currents with their in vivo counterparts.

Challenges for indoor environment research in the new office

This paper discusses new directions for indoor environment research for the following 4 themes: (i) the current change in office work pattern, workplace design, and increasing demands from the work force, (ii) the large individual variation in requirements for optimal conditions pointing at the key factors of individual response and individual control options based on trade-off experiments, (iii) psychosocial factors as determinants of symptoms, comfort, and productivity, and (iv) transient, nonspecific symptoms in the indoor environment, the identification of causes, and long-term consequences.

Synergistic action of protein kinase C theta and calcineurin is sufficient for Fas ligand expression and induction of a crmA-sensitive apoptosis pathway in Jurkat T cells

Deletion of activated peripheral T cell clones by apoptosis requires the regulated expression of Fas ligand (FasL) and sensitization of these cells to CD95-mediated signaling. To investigate the signaling pathways responsible for FasL expression in T cells, we tested-besides subfamily-selective protein kinase C (PKC) inhibitors - the effect of constitutively active mutants of representatives of all PKC subfamilies, i.e. PKCalpha,epsilon,theta,iota, on FasL luciferase promoter reporter constructs. In synergy with a constitutively active form of protein phosphatase 2B calcineurin (CaN), only PKCtheta, but not PKCalpha,epsilon,iota, preferentially induced FasL promoter reporter activity and, consequently, FasL protein expression in Jurkat T cells. Activation of an inducible PKCtheta AE-estrogen receptor fusion mutant led to a CaN-dependent and rapid FasL reporter activity detected as early as 4 h after addition of 4-hydroxytamoxifen, incidating a direct effect of PKCtheta action on FasL expression. Consistently, in Jurkat T cells, expression of PKCtheta AE / CaN significantly enhanced FasL protein expression and apoptosis in a CD95-dependent manner since cell death was not observed in T cells co-expressing the caspase-8 inhibitor crmA. Taken together, our results support the notion that PKCtheta and CaN are sufficient to regulate apoptosis through FasL expression.

Conceptual model for assessment of dermal exposure

Dermal exposure, primarily to pesticides, has been measured for almost half a century. Compared with exposure by inhalation, limited progress has been made towards standardisation of methods of measurement and development of biologically relevant exposure measures. It is suggested that the absence of a consistent terminology and a theoretical model has been an important cause of this lack of progress. Therefore, a consistent terminology based on a multicompartment model for assessment of dermal exposure is proposed that describes the transport of contaminant mass from the source of the hazardous substance to the surface of the skin. Six compartments and two barriers together with eight mass transport processes are described. With the model structure, examples are given of what some existing methods actually measure and where there are limited, or no, methods for measuring the relevant mass in a compartment or transport of mass. The importance of measuring the concentration of contaminant and not mass per area in the skin contaminant layer is stressed, as it is the concentration difference between the skin contamination layer and the perfused tissue that drives uptake. Methods for measuring uptake are currently not available. Measurement of mass, concentration, and the transport processes must be based on a theoretical model. Standardisation of methods of measurement of dermal exposure is strongly recommended.

Measuring strategies and monitoring of the indoor environment

This paper presents key elements on which to base the design of a strategy for a particular indoor environment measurement task. Starting from a general strategy for responding to occupant complaints and conducting epidemiological and intervention studies the paper concentrates on selected key elements, with focus on air contaminants. Strategies for grouping of occupants with the purpose of exposure assessment should aim at optimising exposure contrast between groups, and grouping according to buildings may not be the proper choice. Occupant exposure can be measured by personal sampling or constructed from measured concentrations in microenvironments and activity patterns. The cause of temporal and spatial variability is discussed and guidance is given on the number of samples needed to detect a given change in true concentration level. The sick building syndrome (SBS) is defined as those situations where a high proportion of building occupants are complaining about mucous membrane or skin irritation, general symptoms. When investigating SBS, questionnaires should be used to collect structured information from occupants on perception of environmental conditions, psychosocial factors and symptoms. There is as yet no consensus on choice of length of reference period for reporting symptoms and for estimating exposure. Finally, methods for identifying and quantification of sources of air contaminants are discussed, including lab-scale or full-scale simulation, on-site measurement of source emission, air monitoring, surface sampling, and modelling.

Reperfusion pattern of the immature femoral head after critical ischemia: a microsphere study in pigs

The topographic reperfusion pattern of the femoral head after critical ischemia has not yet been investigated. We determined the blood flow of the porcine hip regions with the femoral head epiphysis divided into 24 subregions by the tracer microsphere technique. Blood flow was measured under steady-state conditions, at the end of a 6-hour increase in intracapsular hip joint pressure to 250 mm Hg, and 4 hours after release of the joint tamponade. Total femoral head epiphyseal blood flow decreased with ischemia and regained steady-state perfusion after tamponade. The reperfusion pattern of the femoral head epiphysis appeared identical with that of the steady state before ischemia. However, 2 of the 11 experimental epiphyses remained ischemic in the reperfusion phase. We conclude that hip joint tamponade above the arterial pressure level for 6 hours causes global ischemia in the femoral head epiphysis in the immature pig, without regional differences in reperfusion, and that reperfusion occurs at a level like that of the steady state before ischemia.

Chernobyl post-accident management: the ETHOS project

ETHOS is a pilot research project supported by the radiation protection research program of the European Commission (DG XII). The project provides an alternative approach to the rehabilitation of living conditions in the contaminated territories of the CIS in the post-accident context of Chernobyl. Initiated at the beginning of 1996, this 3-y project is currently being implemented in the Republic of Belarus. The ETHOS project involves an interdisciplinary team of European researchers from the following institutions: the Centre d'etude sur l'Evaluation de la Protection dans le domaine Nucleaire CEPN (radiological protection, economics), the Institute National d'Agronomie de Paris-Grignon INAPG (agronomy, nature & life management), the Compiegne University of Technology (technological and industrial safety, social trust), and the Mutadis Research Group (sociology, social risk management), which is in charge of the scientific co-ordination of the project. The Belarussian partners in the ETHOS project include the Ministry of Emergencies of Belarus as well as the various local authorities involved with the implementation site. The ETHOS project relies on a strong involvement of the local population in the rehabilitation process. Its main goal is to create conditions for the inhabitants of the contaminated territories to reconstruct their overall quality of life. This reconstruction deals with all the day-to-day aspects that have been affected or threatened by the contamination. The project aims at creating a dynamic process whereby acceptable living conditions can be rebuilt. Radiological security is developed in the ETHOS project as part of a general improvement in the quality of life. The approach does not dissociate the social and the technical dimensions of post-accident management. This is so as to avoid radiological risk assessment and management being reduced purely to a problem for scientific experts, from which local people are excluded, and to take into consideration the problems of acceptability of decisions and the distrust of the population towards experts. These cannot be solved merely by a better communication strategy. This paper presents the main features of the methodological approach of the ETHOS project. It also explains how it is being implemented in the village of Olmany in the district of Stolyn (Brest region) in Belarus since March 1996, as well as its initial achievements.

Loss of heteroplasmy in the displacement loop of brain mitochondrial DNA in astrocytic tumors

The aim of this study was the determination of D-loop heteroplasmy in astrocytic brain tumors. DNA fragments corresponding to the hypervariable region 2 of the mitochondrial displacement loop (D-loop) from 12 astrocytic tumors and 2 corresponding brain samples were cloned into a plasmid vector. Heteroduplex analysis revealed high sequence variability in the brain samples and a subfraction of grade 2 and grade 3 tumors. Furthermore, the results were suggestive of a very low degree of heteroplasmy in all glioblastomas. This was confirmed by direct sequencing of 223 cloned DNA samples from nine individuals. Heteroplasmy was caused in most cases by a well-known length polymorphism of a homopolymeric c-tract. Heteroplasmy of the two reference brain samples was lost in the corresponding tumors. Genes Chromosomes Cancer 26:80-83, 1999.

Visual analogue scales for detecting changes in symptoms of the sick building syndrome in an intervention study

OBJECTIVES

This study tested questionnaires using visual analogue scales (VAS) in a cleaning intervention study and attempted to find a simple way of analyzing the replies to the questionnaires.

METHODS

A VAS questionnaire made up of 26 questions was developed and marked once a week for 28 weeks by the room occupants in 3 buildings. A total of 1248 questionnaires was used in the analysis of the results. A simple model based on the differences between a person's average responses during 2 different periods was used in the analysis.

RESULTS

No clear effect of the cleaning was found. Several significant correlations between different questions were established. Estimates for the design of future studies are given.

CONCLUSIONS

The VAS questionnaire proved to be feasible for this type of study. It is suggested that each intervention period should last 4 weeks if the questionnaire is used once a week. However, the length of the period also depends on the expected latency of the symptoms, on how long it takes for environmental conditions to be affected by the intervention, and on how quickly conditions return to "normal" during control periods.

Immunohistochemical detection of alpha1E voltage-gated Ca(2+) channel isoforms in cerebellum, INS-1 cells, and neuroendocrine cells of the digestive system

Polyclonal antibodies were raised against a common and a specific epitope present only in longer alpha1E isoforms of voltage-gated Ca(2+) channels, yielding an "anti-E-com" and an "anti-E-spec" serum, respectively. The specificity of both sera was established by immunocytochemistry and immunoblotting using stably transfected HEK-293 cells or membrane proteins derived from them. Cells from the insulinoma cell line INS-1, tissue sections from cerebellum, and representative regions of gastrointestinal tract were stained immunocytochemically. INS-1 cells expressed an alpha1E splice variant with a longer carboxy terminus, the so-called alpha1Ee isoform. Similarily, in rat cerebellum, which was used as a reference system, the anti-E-spec serum stained somata and dendrites of Purkinje cells. Only faint staining was seen throughout the cerebellar granule cell layer. After prolonged incubation times, neurons of the molecular layer were stained by anti-E-com, suggesting that a shorter alpha1E isoform is expressed at a lower protein density. In human gastrointestinal tract, endocrine cells of the antral mucosa (stomach), small and large intestine, and islets of Langerhans were stained by the anti-E-spec serum. In addition, staining by the anti-E-spec serum was observed in Paneth cells and in the smooth muscle cell layer of the lamina muscularis mucosae. We conclude that the longer alpha1Ee isoform is expressed in neuroendocrine cells of the digestive system and that, in pancreas, alpha1Ee expression is restricted to the neuroendocrine part, the islets of Langerhans. alpha1E therefore appears to be a common voltage-gated Ca(2+) channel linked to neuroendocrine and related systems of the body.

Isoforms of alpha1E voltage-gated calcium channels in rat cerebellar granule cells--detection of major calcium channel alpha1-transcripts by reverse transcription-polymerase chain reaction

In primary cultures of rat cerebellar granule cells, transcripts of voltage-gated Ca2+ channels have been amplified by reverse transcription-polymerase chain reaction and identified by sequencing of subcloned polymerase chain reaction products. In these neurons cultured for six to eight days in vitro, fragments of the three major transcripts alpha1C, alpha1A, and alpha1E are detected using degenerated oligonucleotide primer pairs under highly stringent conditions. Whole-cell Ca2+ current recordings from six to eight days in vitro granule cells show that most of the current is due to L-type (25%), P-type (33%) and R-type (30%) Ca2+ channels. These data support the correlation between alpha1A and P-type Ca2+ channels (G1) and between alpha1E and R-type channels (G2 and G3). By including specific primer pairs for alpha1E the complimentary DNA fragments of indicative regions of alpha1E isoforms are amplified corresponding to the three most variable regions of alpha1E, the 5'-end, the II/III-loop, and the central part of the 3'-end. Although the complementary DNA fragments of the 5'-end of rat alpha1E yield a uniform reverse transcription-polymerase chain reaction product, its structure is unusual in the sense that it is longer than in the cloned rat alpha1E complementary DNA. It corresponds to the alpha1E isoform reported for mouse and human brain and is also expressed in cerebellum and cerebrum of rat brain as the major or maybe even the only variant of alpha1E. While fragments of a new rat alpha1E isoform are amplified from the 5'-end, three known fragments of the II/III-loop and two known isoforms homologue to the 3'-coding region are detected, which in the last case are discriminated by a 129 base pair insertion. The shift of the alpha1E expression from a pattern seen in cerebellum (alpha1Ee) to a pattern identified in other regions of the brain (alpha1E-3) is discussed. These data show that: (i) alpha1E is expressed in rat brain as a structural homologue to the mouse and human alpha1E; and (ii) rat cerebellar granule cells in primary culture express a set of alpha1E isoforms, containing two different sized carboxy termini. Since no new transcripts of high-voltage-activated Ca2+ channels genes are identified using degenerate oligonucleotide primer pairs, the two isoforms differentiated by the 129 base pair insertion might correspond to the two R-type channels, G2 and G3, characterized in these neurons. Functional studies including recombinant cells with the different proposed isoforms should provide more evidence for this conclusion.

The expression of the H19 gene and its function in human bladder carcinoma cell lines

The human H19 gene is a paternally imprinted oncofetal gene, highly expressed in several fetal tissues, down-regulated in nearly all adult tissues but re-expressed in carcinomas of tissues which express the gene in fetal life. It has no known protein product and till today, no function could be designated to H19 RNA. Cells derived from bladder carcinomas and hepatocellular carcinomas were transfected with plasmids carrying a luciferase reporter gene under the control of a 800 nucleotides long promoter region of the H19 gene either alone or together with different parts of a 5 kb downstream region, previously shown to possess enhancer activity. Our results provide evidence that three regions of the 3' downstream sequence can independently stimulate the H19 promoter activity in a tissue and cell specific manner. The growth rate of two cell populations, both derived from the same bladder carcinoma cell line and which differ in their H19 RNA content, were compared. The cells with a high H19 RNA level stopped their proliferation after 48 h when cultivated in a low serum containing media while the cells lacking H19 RNA continued their proliferation for at least an additional 48 h period.

Blockade of Ba2+ current through human alpha1E channels by two steroid analogs, (+)-ACN and (+)-ECN

Previous work suggests that different neuroactive steroids may exhibit some selectivity in their blocking effects on different high-voltage activated (HVA) Ca2+ currents. At least some of these effects appear to involve direct blocking actions on Ca2+ channels. Thus, direct investigation of the effects of various steroids on cloned Ca2+ channel variants may lead to the development of potent and selective small-molecular weight Ca2+ channel blockers. Here we examine the effects of two steroids on a cloned human alpha1E Ca2+ channel both with and without a beta3 subunit, when expressed in HEK293 cells. One compound, (+)-ACN, has been previously shown to block N-, Q-, and R-subtypes of HVA current without affecting L- and P-type current. The second compound, (+)-ECN, weakly blocks total HVA current in hippocampal neurons. (+)-ECN differs from (+)-ACN in lacking effects on GABA receptors, but shares with (+)-ACN an ability to partially inhibit T current in DRG neurons (Todorovic, S.M., Prakriya, M., Nakashima, Y.M. et al., 1998. Enantioselective blockade of T-type Ca2+ current in adult rat sensory neurons by a steroid lacking GABA-mimetic activity. Mol. Pharmacol. 54, 918-927). (+)-ACN can block 100% of Ba2+ current in HEK cells arising either from the alpha1E subunit (IC50 approximate to 10 microM) or the alpha1Ebeta3 combination (IC50 approximate to 5 microM), while (+)-ECN maximally blocks only about 80% of the alpha1E (10 microM) or alpha1Ebeta3 (16 microM) current. Blockade by (+)-ACN exhibits several differences from blockade by (+)-ECN. (+)-ACN increases the apparent rate of onset of inactivation, particularly for the alpha1E variant, slows recovery from inactivation, and more profoundly shifts the voltage-dependence of current availability for both alpha1E and alpha1Ebeta3 variants than does (+)-ECN. Although the complexity of the normal inactivation kinetics of alpha1E variants makes interpretation of the (+)-ACN-induced kinetic alterations difficult, the results suggest that the two steroids are to some extent acting by distinct mechanisms, and perhaps at different sites.

Rapid mucosal CD4(+) T-cell depletion and enteropathy in simian immunodeficiency virus-infected rhesus macaques

BACKGROUND & AIMS

Human immunodeficiency virus (HIV) infection leads to severe immunologic and functional disturbances in the intestinal tract in late stages of the disease. Information on mucosal pathology directly after infection is limited. We characterized this early phase in rhesus macaques infected with simian immunodeficiency virus (SIV).

METHODS

Eight rhesus macaques were infected with SIV. Upper endoscopy was performed at defined times before and after infection. Viral load, percentage of CD4(+) T cells, villus height, crypt depth, and Ki-67-positive crypt cells were analyzed in duodenal biopsy specimens. Serum beta-carotene and vitamin D levels were assessed.

RESULTS

A rapid increase of duodenal SIV core protein (p27) concentration and an almost complete loss of intestinal CD4(+) T cells was found within 2 weeks after infection. A decrease of villus height was observed, and the percentage of Ki-67-positive (proliferating) crypt cells increased. Serum concentrations of vitamin D decreased in 6 of 8 animals, and beta-carotene concentrations decreased in 3 of 8 animals after infection.

CONCLUSIONS

Mucosal SIV replication and intestinal CD4(+) T cell depletion are early events in SIV-infected rhesus macaques. The structural changes of the mucosa strongly support the concept of HIV/SIV-induced enteropathy. In contrast to late-stage human HIV infection, early small intestinal villous atrophy in SIV infection is associated with crypt hyperplasia.

[The femoropatellar endoprosthesis--still of value today?]

PURPOSE

Aim of this study was the examination of clinical middle- and long-term results of total femoropatellar endoprostheses type Lubinus (Link, Germany).

METHOD

From 1983 to 1996 12 patients (15 joints) underwent total femoropatellar joint replacement (type Lubinus, Link, Hamburg). All of them have been controlled 7.2 +/- 2.6 years (2 to 12 years) after surgery. The indication was primary osteoarthritis in 6, chondrocalcinosis in 2 and rheumatoid arthritis in 7 cases. In addition to the femoropatellar implants femorotibial endoprostheses have been used in 10 knees: 2 unicondylar medial, 1 unicondylar lateral and 7 bicondylar unicompartimental ones.

RESULTS

According to a modified Hungerford knee rating scale 8 knees resulted excellent, 2 fair and 4 poor. One knee was excluded after revision surgery due to a loosened tibial component of a medial unicompartimental knee arthroplasty. The 4 poor outcomes resulted from femoropatellar replacements in chondrocalcinosis (2 cases), rheumatoid arthritis and osteoarthritis, (one case each), affecting the femorotibial joint as well.

CONCLUSIONS

In those cases of simultaneous femorotibial joint affection--even if this is merely slight and beginning and if the femoropatellar complaints are actually clearly dominating--the sole femoropatellar surface replacement seems to be contraindicated according to our experiences. Providing correct and strict indications this endoprosthesis can be recommended for sole femoropatellar osteoarthritis especially since loosening of endoprosthetic components was not been found in this study.

The profile of urinary metabolites of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone in rats is determined by its pulmonary metabolism

Metabolism of the tobacco specific nitrosamine 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) in rats was compared to metabolism in primary lung and liver cells. Untreated rats and rats pretreated with phenobarbital, acetone or phenethyl isothiocyanate (PEITC) were used for all experiments. Also the influence of [-]-1-methyl-2-[3-pyridyl]-pyrrolidine (nicotine) administered concomitantly with NNK, or incubated with isolated cells, upon NNK metabolism was investigated and found to be only marginal upon alpha-hydroxylation and pyridine N-oxidation in vivo. In hepatocytes nicotine inhibited NNK pyridine N-oxidation, alpha-hydroxylation and glucuronidation of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL), whereas in lung cells the influence of nicotine was not as pronounced. In vivo phenobarbital induced alpha-hydroxylation and pyridine N-oxidation. In vitro the effects of the modulators were most pronounced upon hepatocytes, where phenobarbital greatly induced pyridine N-oxidation and PEITC inhibited alpha-hydroxylation. NNAL was conjugated to its beta-glucuronide in lung cells at four times higher rates than in hepatocytes. The ratios of the sum of N-oxides to the sum of alpha-hydroxylation products in vivo were similar to those in lung cells, especially at low NNK concentrations (1 microM), while in hepatocytes alpha-hydroxylation was more pronounced. The same correlation of metabolism in isolated lung cells with whole rats was observed if oxidative NNAL metabolism was related to oxidative NNK metabolism. Here hepatocytes showed a much higher formation of NNAL oxidation products than either lung cells formed, or rats excreted in urine. This was true despite a lower rate of metabolism in the lung than in liver if based on cell number, the rate based on mg protein was four times higher in lung than liver. Only after phenobarbital treatment was the contribution of hepatic metabolism to excreted metabolites important. In conclusion the lung which is also the target of NNK carcinogenesis, and not the liver, is the organ with the most important contribution to NNK and NNAL metabolism at concentrations relevant to human exposure.