The pathogenesis of diabetic complications: the role of DNA injury and poly(ADP-ribose) polymerase activation in peroxynitrite-mediated cytotoxicity

Recent work has demonstrated that hyperglycemia-induced overproduction of superoxide by the mitochondrial electron-transport chain triggers several pathways of injury [(protein kinase C (PKC), hexosamine and polyol pathway fluxes, advanced glycation end product formation (AGE)] involved in the pathogenesis of diabetic complications by inhibiting glyceraldehyde-3-phosphate dehydrogenase (GAPDH) activity. Increased oxidative and nitrosative stress activates the nuclear enzyme, poly(ADP-ribose) polymerase-1 (PARP). PARP activation, on one hand, depletes its substrate, NAD+, slowing the rate of glycolysis, electron transport and ATP formation. On the other hand, PARP activation results in inhibition of GAPDH by poly-ADP-ribosylation. These processes result in acute endothelial dysfunction in diabetic blood vessels, which importantly contributes to the development of various diabetic complications. Accordingly, hyperglycemia-induced activation of PKC and AGE formation are prevented by inhibition of PARP activity. Furthermore, inhibition of PARP protects against diabetic cardiovascular dysfunction in rodent models of cardiomyopathy, nephropathy, neuropathy, and retinopathy. PARP activation is also present in microvasculature of human diabetic subjects. The present review focuses on the role of PARP in diabetic complications and emphasizes the therapeutic potential of PARP inhibition in the prevention or reversal of diabetic complications.

Fatal suicide cases from 1991 to 2000 in Szeged, Hungary

The aim of this study is to analyze the fatalities due to suicide in the period of 1991-2000. The autopsy reports of 719 suicide cases during that period of the Department of Forensic Medicine, University of Szeged were reviewed retrospectively. The victim's age, sex, way of commitment, place of death, the presence of alcohol and drug influence and survival time were recorded. Five hundred and one of the (69.6%) total 719 suicide fatalities were men and 218 (30.4%) were women. The largest age groups were 41-50 in men, in women we experienced a 'double-peak' of age groups 41-50 and 71-80. The most frequent way of committal was hanging (46%). The results revealed that 38.8% of the 474 victims whose blood and/or urine alcohol concentration measurement were carried out consumed alcohol prior to the act. The presence of licit drugs in 12% of not drug-related cases were experienced.

Molecular Identification of Oidium neolycopersici as the Causal Agent of the Recent Tomato Powdery Mildew Epidemics in North America

A previous morphological study of Oidium anamorphs responsible for the recent tomato (Lycopersicon esculentum) powdery mildew outbreaks worldwide suggested that, despite controversial data in the literature, the North American epidemics were caused solely by a newly erected species, O. neolycopersici. We report here the first molecular evidence that the North American anamorphs do belong to O. neolycopersici. The internal transcribed spacer sequences of the North American anamorphs of this study were identical with those of three Japanese and four European specimens of O. neolycopersici. A morphological study confirmed that all the North American Oidium anamorphs included in this study produced conidia singly, similar to O. neolycopersici. These fungi were readily distinguished from O. lycopersici, which produces conidia in chains and is known to infect tomato only in Australia. The phylogenetic analysis showed that O. neolycopersici is a distinct powdery mildew species, and it is neither identical nor closely related to any known polyphagous species of the Erysiphaceae. Apparently, it was introduced into the United States and Canada only in the 1990s, but its origin is still unknown.

[Long-term prognostic value of positive peritoneal washing in colon cancer]

We examined the prognostic value of free malignant cells in the peritoneal cavity of patients with colon adenocarcinoma. In 1996-1999, 88 patients underwent peritoneal washing with cytologic analysis immediately before elective colon resection for adenocarcinoma with no evidence of peritoneal metastases. Peritoneal washing fluid was collected before abdominal exploration centrifuged immediately and stained with the May-Grünwald-Giemsa and Harris-Shorr methods. Malignancy was defined as recommended by Papanicolaou. Free malignant cells in peritoneal fluid were found in 25 of 88 (28%) patients (Dukes A 0, of 11, Dukes B 10 of 31, Dukes C 11 of 37, Dukes D 4 of 9). The positive rate was 24 of 75 (32%) among patients with tumors involving the serous layer and 1 of 13 (8%) among the others (p = 0.00989). Positive peritoneal washing was not significantly associated with survival in multivariate analysis.

CONCLUSION

The presence of free malignant cells in the peritoneal cavity of patients with colon cancer provided no further prognostic information relative to the Dukes classification in this study. The 5 years survival rates were 48% among patients with positive and negative peritoneal washing respectively (p = 0.09).

Poly(ADP-Ribose) polymerase promotes cardiac remodeling, contractile failure, and translocation of apoptosis-inducing factor in a murine experimental model of aortic banding and heart failure

Oxidant stress-induced activation of poly(ADP-ribose) polymerase (PARP) plays a role in the pathogenesis of various cardiovascular diseases. We have now investigated the role of PARP in the process of cardiac remodeling and heart failure in a mouse model of heart failure induced by transverse aortic constriction (banding). The catalytic activity of PARP was inhibited by the potent isoindolinone-based PARP inhibitor INO-1001 or by PARP-1 genetic deficiency. PARP inhibition prevented the pressure overload-induced decrease in cardiac contractile function, despite the pressure gradient between both carotid arteries being comparable in the two experimental groups. The development of hypertrophy, the formation of collagen in the hearts, and the mitochondrial-to-nuclear translocation of the cell death factor apoptosis-inducing factor (AIF) were attenuated by PARP inhibition. The ability of the inhibitor to block the catalytic activity of PARP was confirmed by immunohistochemical detection of poly(ADP-ribose), the product of the enzyme in the heart. Plasma levels of INO-1001, as measured at the end of the experiments, were in the concentration range sufficient to block the oxidant-mediated activation of PARP in murine cardiac myocytes in vitro. Myocardial hypertrophy and AIF translocation was also reduced in PARP-1-deficient mice undergoing aortic banding, compared with their wild-type counterparts. Overall, the current results demonstrate the importance of poly(ADP-ribos)ylation in the pathogenesis of banding-induced heart failure.

Natural variation of drug susceptibility in wild-type human immunodeficiency virus type 1

Wild-type viruses from the ViroLogic phenotype-genotype database were evaluated to determine the upper confidence limit of the drug susceptibility distributions, or "biological cutoffs," for the PhenoSense HIV phenotypic drug susceptibility assay. Definition of the natural variation in drug susceptibility in wild-type human immunodeficiency virus (HIV) type 1 isolates is necessary to determine the prevalence of innate drug resistance and to assess the capability of the PhenoSense assay to reliably measure subtle reductions in drug susceptibility. The biological cutoffs for each drug, defined by the 99th percentile of the fold change in the 50% inhibitory concentration distributions or the mean fold change plus 2 standard deviations, were lower than those previously reported for other phenotypic assays and lower than the clinically relevant cutoffs previously defined for the PhenoSense assay. The 99th percentile fold change values ranged from 1.2 (tenofovir) to 1.8 (zidovudine) for nucleoside reverse transcriptase RT inhibitors (RTIs), from 3.0 (efavirenz) to 6.2 (delavirdine) for nonnucleoside RTIs, and from 1.6 (lopinavir) to 3.6 (nelfinavir) for protease inhibitors. To evaluate the potential role of intrinsic assay variability in the observed variations in the drug susceptibilities of wild-type isolates, 10 reference viruses with different drug susceptibility patterns were tested 8 to 30 times each. The median coefficients of variation in fold change for the reference viruses ranged from 12 to 18% for all drugs except zidovudine (32%), strongly suggesting that the observed differences in wild-type virus susceptibility to the different drugs is related to intrinsic virus variability rather than assay variability. The low biological cutoffs and assay variability suggest that the PhenoSense HIV assay may assist in defining clinically relevant susceptibility cutoffs for resistance to antiretroviral drugs.

Multilevel callus distraction: a novel idea to shorten the lengthening time

Lower extremity inequality is a common problem in everyday orthopaedic practice. The leg discrepancy can lead to variety of other problems, i.e., spinal problems. Surgical intervention is very demanding and requires patient compliance. Wagner's and Ilizarov's elongation technique are most commonly used worldwide, but it gives satisfactory results only in a long period of time and as we know there could be several inconvenient outcomes. Our idea aims at shortening this time period, and avoiding some of the inconvenient outcomes. Unfortunately we do not have the opportunity to go further in our investigations, but we hope that someone interested in this field will have an idea which would make continuation possible.

A review of fungal antagonists of powdery mildews and their potential as biocontrol agents

There are approximately 40 fungal species that have so far been reported as natural antagonists of powdery mildews or have been tested as their potential biocontrol agents. This review summarizes the published data on their identification, taxonomy, ecology, modes of action and biocontrol efficacy. The results obtained with the two products already registered, AQ10 Biofungicide and Sporodex, are also discussed.

Advances in the identification of emerging powdery mildew fungi using morphological and molecular data

Recently, the classical morphological criteria and host range data used in the identification of powdery mildew fungi were supplemented with scanning electron microscope (SEM) and molecular phylogenetic analyses. This paper discusses the joint use of these methods in the identification of powdery mildew anamorphs causing new or emerging plant diseases in different parts of the world.

[The "hospital review" in 1865: the first journal for hospital service in Hungary]

This article is a concise history of the first Hungarian journal for hospital medicine published in Pozsony (Bratislava, Pressburg) from the year 1865. The editorial board of the Kórházi Szemle (Hospital Review) consisting of young physicians (Zlamál, Gotthard, Kanka) attempted to give a complete overview on Hungarian hospital research, including new ways of therapies and hospital statistics as well. Analysing the publications of the journal author concludes, that the hospital of Pozsony (Bratislava) founded in 1864 represented a rather high niveau of healing. The first tracheotomies, and the first histologic tests have been performed here in the region.

[Observations regarding lymphatic gastric drainage in malignant gastric pathology through intra-operatory lymphography]

The authors became interested in the lymphatic drainage of the stomach in order to attempt to determine for each region the type of drainage and the risk of cancer spread. They studied 50 dissection, including the stomach, 115 cases records of gastric carcinoma, 8 lymphographies by ultrafluid lipiodal, and 48 preoperative injections of vital colorant. The system of drainage proposed by Rouvière was on the whole confirmed; however, one should emphasize the doubling of the hepatic chain, the existence of long collectors which bypass a relay in the left gastric artery, the importance of the posterior gastric artery which transmits the lymphatic of the splenic chain. Finally, the authors emphasize the existence of 3 longitudinal areas on the stomach where the presence or absence of valvules in the subserous collectors orients the lymph towards the lesser or greater curvature of the stomach, which easily explains the onset of isolated carcinomatous adenopathy, situated on the curvature opposite the neoplasm.

Contradictions of derotation in scoliosis surgery using the CD principle

Current literature has increasingly emphasized the problem of derotation in scoliotic deformities. The Cotrel-Dubousset (CD) principle as a means of correcting rotation has been questioned by various authors. This paper aims to draw attention, using algebraic methods, to the importance of the remaining rotational deformities, and to suggest the introduction of the notion 'rotational balance'.

Cyclic stretch enhances the expression and activity of coronary endothelium-derived hyperpolarizing factor synthase

Endothelium-derived hyperpolarizing factor (EDHF) mediates NO/prostacyclin-independent relaxation in the coronary circulation. Because hemodynamic stimuli modulate endothelial gene expression and because coronary arteries are subjected to pronounced variations in vessel distension, we determined the effects of cyclic stretch on the expression and activity of the coronary EDHF synthase/cytochrome P450 (CYP) 2C8/9. In cultured porcine coronary and human umbilical vein endothelial cells, acute application of cyclic stretch (6%, 1 Hz, 10 minutes) elicited the generation of 8,9-epoxyeicosatrienoic acid (EET), 11,12-EET, and 14,15-EET. Prolonged stretch (4 to 36 hours) increased the expression of CYP 2C mRNA and protein 5- to 10-fold and was accompanied by a 4- to 8-fold increase in EET generation. A corresponding increase in CYP 2C mRNA and protein was also observed in pressurized segments of porcine coronary artery perfused under pulsatile conditions (8%, 1 Hz) for 6 hours. Although in cultured endothelial cells, cyclic stretch elicited the rapid activation of tyrosine kinases as well as Akt and the p38 mitogen-activated protein kinase, the mechanism by which cyclic stretch induces the expression of CYP 2C could not be elucidated, because inhibitors of these pathways induced CYP 2C expression in cells maintained under static conditions. These results have identified coronary EDHF synthase/CYP 2C as a novel mechanosensitive gene product in native and cultured endothelial cells. Because this enzyme generates both EETs and superoxide anions, this finding has wide-reaching implications for vascular homeostasis in conditions of manifest endothelial dysfunction.

First Report of Erysiphe sedi on Sedum spectabile in North America

Since 1997, powdery mildew infections have been repeatedly observed on Sedum spectabile plants, cv. Autumn Joy, grown as ornamentals in commercial greenhouses in New York. Circular patches of gray mycelia appeared and spread on upper and occasionally on lower leaf surfaces followed by necrosis of the leaf tissues and defoliation. The new disease reduced the market value of the infected ornamentals and required chemical control. The pathogen produced conidia singly on 2- to 3-celled conidiophores occurring on the ectophytic hyphae. Conidia were subcylindrical, measured 27 to 36 μm × 13 to 17 μm, and contained no fibrosin bodies. Germinating conidia produced a short germ tube, 5 to 30 μm, terminating in a lobed appressorium. Hyphal appressoria were lobed to multi-lobed, opposite or spread along the hyphae. Cleistothecia were not found. Based on conidial characteristics, the pathogen was identified as Erysiphe sedi Braun. To confirm pathogenicity, potted healthy S. spectabile plants were placed near infected plants in the greenhouse. In addition, detached S. spectabile leaves were inoculated with the pathogen by touching them to powdery mildew colonies and then placed in plates filled with one layer of polystyrene balls floated in water. Plates were covered and kept in the laboratory. Uninfected potted plants kept in another greenhouse and noninoculated detached leaves served as controls. After 1 week, powdery mildew appeared on all infected plants and leaves exposed to or inoculated with the pathogen. The pathogen was morphologically identical to the original fungus. No symptoms were observed on the controls. E. sedi is a common Asiatic powdery mildew species infecting many crassulaceous plants (1,2) and was introduced to Eastern Europe from Asia (2). To our knowledge, this is the first report of E. sedi in North America. References: (1) U. Braun. Beih. Nova Hedwigia 89:1, 1987. (2) U. Braun. The Powdery Mildews (Erysiphales) of Europe. Gustav Fisher Verlag, Jena, 1995.

[The diagnostic strategy in abdominal trauma]

Diagnosis of a deep visceral lesion in an adult following abdominal contusion is almost always difficult as the abdominal signs are later or masked by associated lesions. All of the controlled studies agree on the superiority of peritoneal puncture-lavage over metrosonography or CT scan in the diagnosis of homeoperitoneu. The diagnostic performance of CT, TDM in the identification of lesions solid organs is very much better that that of ultrasonography. The diagnosis of an isolated lesion of a hallow viscus benefited from progress in imaging to a much lesser degree an peritoneal puncture lavage with leucocyte count remains the key examination. The diagnostic strategy must be based on the patient's clinical condition and on this hierarchy of complementary investigations.

[The intraoperative colonic irrigation in emergency surgery]

Bowel preparations is frequently impossible in various ante colonic diseases, such as left-sided colonic obstruction. The goal of intraoperative colonic irrigation is to obtain, during surgery, a bowel preparation offering the possibility of primary resection with immediate anastomosis, when preoperative bowel preparation has not been feasible. Technical aspects of intra-operative colonic irrigation are described. Indications for this methods are presented: left-sided obstructing carcinomas, diverticulitis, more rarely inflammatory stenosis or functional obstruction. The surgical management of left colonic emergencies has evolved in the past few decades. Recently, there has been increasing interest in resection with primary anastomosis in selected cases. The post operative mortality rate was 13 per cent. The incidence of clinical anastomotic leakage was 6.65 per cent.

Chiroptical properties of 2,3-dihydrobenzo[b]furan and chromane chromophores in naturally occurring O-heterocycles

The correlation between the helicity (absolute conformation) of the O-heterocyclic ring of chiral 2,3-dihydrobenzo[b]furan (1) and chromane (2) derivatives and their (1)L(b) band CD was investigated. The same helicity rule was found for both unsubstituted chromophores: P/M helicity of the heterocyclic ring leads to a negative/positive CD within the (1)L(b) band. While the substitution of the fused benzene ring by achiral substituents does not change this helicity rule for the chromane chromophore, it leads to its inversion for the 2,3-dihydrobenzo[b]furan chromophores. On the basis of these observations, the published absolute configurations of natural flavonol and pterocarpan derivatives were confirmed and the configurational assignments of several natural neolignans revised.

The coronary endothelium-derived hyperpolarizing factor (EDHF) stimulates multiple signalling pathways and proliferation in vascular cells

In the present study we determined whether the endothelium-derived hyperpolarizing factor (EDHF), in addition to its acute effects on vascular tone, activates intracellular signalling pathways other than those associated with Ca2+-dependent K+ channels. EDHF was generated by rhythmic distension of porcine coronary arteries under conditions of combined nitric oxide (NO) synthase/cyclo-oxygenase blockade, and the EDHF-containing luminal incubate was applied to cultured human coronary endothelial or smooth muscle cells. In both cell types, the luminal incubate activated tyrosine kinases, the mitogen-activated protein (MAP) kinases, extracellular signal regulated kinases 1 and 2 (Erk1/2) and p38, as well as protein kinase B/Akt. The constituent responsible for Erk1/2 phosphorylation was identified as a cytochrome P450 (CYP) metabolite, as Erk1/2 activation was attenuated by pretreating the EDHF donor with the CYP 2C inhibitor sulfaphenazole as well as by CYP 2C antisense oligonucleotides. Erk1/2 phosphorylation in detector cells was also observed following the transfer of supernatant from cultured endothelial cells treated with the CYP inducer beta-naphthoflavone. The CYP 2C product 11,12-epoxyeicosatrienoic acid (11,12-EET) also activated tyrosine kinases, Erk1/2 and p38 MAP kinase. Overexpression of CYP 2C8 in native porcine coronary artery endothelial cells resulted in an increase in endothelial 11,12-EET production and Erk1/2 phosphorylation compared to that detected in untreated cells or cells transfected with an antisense CYP 2C8. Endothelial cell number was unaffected by transfection with LacZ or CYP 2C8 antisense but was significantly enhanced in cells overexpressing CYP 2C8. These observations indicate that EDHF/11,12-EET is not simply a vasodilator and that its continuous release under pulsatile conditions in vivo may affect vascular cell signalling and proliferation.

Investigation of oxacillin-hydrolyzing beta-lactamase in borderline methicillin-resistant clinical isolates of Staphylococcus aureus

BACKGROUND

Mechanisms of borderline resistance of Staphylococcus aureus to penicillinase-resistant penicillins (PRPs) may include hyperproduction of classical penicillinase and/or production of beta-lactamase hydrolyzing also PRPs.

METHODS

beta-Lactamase activity of whole cells and purified enzymes was estimated spectrophotometrically and in isolated cytoplasmic membranes by bioassay with Bacillus subtilis as test strain.

RESULTS

Out of 53 clinical isolates of S. aureus, 18 showed oxacillin MIC values from 0.5 to 2 microg/ml, which were reduced by sulbactam and/or clavulanic acid in the case of four isolates producing large quantities of inducible, type A beta-lactamase. Cytoplasmic membranes isolated from these strains showed oxacillin-hydrolyzing activity. One of these strains was grown also in the presence of globomycin, an antibiotic known to interfere with the anchorage of membrane lipoproteins; this treatment eliminated the oxacillin-hydrolyzing activity.

CONCLUSIONS

The resistance in these strains was due to a membrane-bound lipoprotein with oxacillin-hydrolyzing activity.

[Injuries to the duodenum and pancreas in 42 operated cases]

42 consecutive patients who sustained injuries to the duodenum or/and pancreas were admitted to our hospital. Over a twenty year period 32 blunt injuries and 10 penetrating injuries were encountered. Penetrating injuries were always suspected and treated by time: following blunt injury diagnostic delay was encountered in 14 patients and insufficient surgical procedure because of intra-operative misinterpretation in 2 patients. Most of the patients had associated intra-abdominal organ injuries. Adjusts to diagnosis such as abdominal roentgenograms, serum amylase levels and gastroduodenography was not helpful. CT scan and ultrasound allowed to confirm the suspected diagnosis in 3 cases only. Intraoperative diagnosis was also challenging. Complete mobilization of the strictures surrounding the duodenum and the pancreas to provide entire exposure was necessary in 12 patients treated first in a peripheral hospital, diagnosis of the injury have been missed at first laparotomy and reoperation was necessary in all of them. Suture closure of the duodenum and drainage of the pancreatic region wee the most common reparative techniques used. More complicated procedures with pancreatic and/or duodenal resection were performed in 12 patients. Overall mortality in patients surviving more than 24 hours was 14%. Suture live dehiscence after delayed operation (4) and 2 deaths due to brain injury.

Determination of the absolute configuration of synthetic pterocarpans by chiral HPLC using on-line CD detection

Resolution of synthetic racemic pterocarpans was achieved by CD monitored HPLC using a chiral stationary phase. No sign of exciton coupling was seen in the CD spectra of the pterocarpan enantiomers. The predominance of the chromane chromophore was indicated by the high intensity of the (1) L(b) band. The chirality of both the chromane and dihydrobenzo[b]furane chromophores was found to be governed by the second chiral sphere. An oxygen atom in pseudoaxial position at the benzylic atom of the chroman ring system gave rise to an increased third-sphere contribution and the positive sign of the (1) L(b) and negative sign of the (1) L(a) band. This resulted in a general positive-negative-negative sign pattern of the (1) L(b), (1) L(a) and (1) B(b) bands of the second-eluted enantiomer of P helicity suggesting homochirality and the same absolute configuration of the chiral centers.

Enhancement of presynaptic neuronal excitability by correlated presynaptic and postsynaptic spiking

Use-dependent modifications, such as long-term potentiation (LTP) of synaptic efficacy, are believed to be essential for information storage in the nervous system. Repetitive correlated spiking of presynaptic and postsynaptic neurons can induce LTP at excitatory glutamatergic synapses. In cultured hippocampal neurons, we show that repetitive correlated activity also results in a rapid and persistent enhancement of presynaptic excitability, decreasing the threshold for spiking and reducing the variability of interspike intervals. Furthermore, we found that correlated activity modified sodium channel gating in the presynaptic neuron. This modification of presynaptic excitability required a temporal order between presynaptic and postsynaptic spiking and activation of postsynaptic NMDA receptors. Presynaptic inhibition of protein kinase C abolished the change in excitability without affecting LTP. Such rapid activity-dependent changes in the efficacy of presynaptic spiking may be involved in the processing and storage of information within the nervous system.

[Acute colonic pseudo-obstruction or Ogilvie syndrome]

Acute colonic pseudo-obstruction is a clinical condition with the symptoms, signs and radiological appearances of acute large bowel obstruction but without any apparent mechanical cause. The mortality rate for patients undergoing surgery was 57%. The incidence of caecal-perforation was 1 for 7 patients. The pathogenesis of the syndrome is unknown but in more then 80% of cases many conditions that have been associated with this syndrome. The efficacy of prepulsid agents for the treatment of syndrome remains to be assessed in a controlled study. In our patients clinical observation, radiologic studies and direct observation during several hours of surgery had shown a complete lack of propulsive motility within of the large bowel. This can be related to the ganglionitis and later to the aganglionosis of the mesenteric plexus.

Nifedipine increases cytochrome P4502C expression and endothelium-derived hyperpolarizing factor-mediated responses in coronary arteries

In addition to NO and prostacyclin, endothelial cells release a factor that elicits vasodilatation by hyperpolarizing the underlying vascular smooth muscle cells. In some vascular beds, this so-called endothelium-derived hyperpolarizing factor (EDHF) displays the characteristics of a cytochrome P450 (CYP)-derived arachidonic acid metabolite, such as an epoxyeicosatrienoic acid. Native porcine and cultured human coronary artery endothelial cells were screened for CYP epoxygenases, and CYP2B, CYP2C, and CYP2J were detected with reverse transcription-polymerase chain reaction. The CYP inducer beta-naphthoflavone and the Ca(2+) antagonist nifedipine significantly increased CYP2C mRNA but did not change the expression of CYP2J or CYP2B. To determine the relationship between CYP2C expression and EDHF production in native endothelial cells, we incubated porcine coronary arteries with nifedipine. Nifedipine enhanced endothelial CYP2C protein expression, as well as the generation of 11,12-epoxyeicosatrienoic acid. In organ bath experiments, pretreatment with nifedipine enhanced bradykinin-induced, EDHF-mediated relaxations as well as the concomitant hyperpolarization of smooth muscle cells. The specific CYP2C9 inhibitor sulfaphenazole, on the other hand, significantly attenuated EDHF-mediated hyperpolarization and relaxation. These results demonstrate that in porcine coronary arteries, the elevated expression of a CYP epoxygenase, homologous to CYP2C8/9, is associated with enhanced EDHF-mediated hyperpolarization in response to bradykinin. Therefore, we propose that an isozyme of CYP2C is the most likely candidate for the CYP-dependent EDHF synthase in porcine coronary arteries.

[Observations regarding surgical treatment in liver trauma]

The high mortality rate in hepatic trauma is a concern for the surgeons on duty, who most know the physiopathological problems and the decisions needed in view of both hepatic and extrahepatic injures. The mortality rate from liver trauma has fallen from 60% at the beginning of this century, blunt trauma to the abdomen from accidents, is responsible for 80-90% of all liver injures in Europe. The severity of liver injuries in 268 patients in a prospective study (1978-1998), were treated according to a defined protocol. Non operative management was used in first day, for those who were haemodynamically stable on admission. In unstable patients who proceeded to surgery, under optimal condition the mortality rate was 34.3%. Death in patients with multiple injures should only rarely result from liver trauma. 92 patients with minor injures (grade I-II) were treated by simple suture, with mortality rate of 6%. 116 patients (43%) sustained complex hepatic injures (grade III to V); 64 patients with grade III (23%), 36 with grade IV (13%). 16 Patients (5%) grade V, injury under went finger fracture of hepatic parenchyma alone 36. The mortality rate in this group was 18% (III), 36% (IV). 16 patients with grad V injury were managed with 68% mortality rate. Juxtahepatic veins and retrohepatic V.C.I. injury continue to carry a prohibitive mortality rate (90-100%).

Targeting lipopolysaccharides by the nontoxic polymyxin B nonapeptide sensitizes resistant Escherichia coli to the bactericidal effect of human neutrophils

The nonapeptide of polymyxin B (PMBN) has been reported to sensitize various pathogenic gram-negative bacteria to the direct bactericidal effect of human serum. To investigate the impact of PMBN on human neutrophil-effected killing of the serum- and phagocytosis-resistant Escherichia coli strains C14 and O111, serum was coapplied with PMBN or with neutrophils, but this did not result in decreased numbers of viable bacteria. In contrast, the most potent bacterial killing occurred in the presence of neutrophils plus serum components plus PMBN. The effect of this on E. coli C14 was the appearance of inositol phosphates, diacylglycerol, respiratory burst, elastase liberation, and generation of lipid mediators (leukotriene B(4), 5-HETE, and platelet-activating factor). Strong neutrophil activation required early, but not late, complement components and was blocked by inhibition of phagocytosis with cytochalasin D. PMBN seems to cause dramatic support of natural host defense by complement-dependent sensitization of E. coli to the bactericidal efficacy of human neutrophils.

E. coli hemolysin-induced lipid mediator metabolism in alveolar macrophages: impact of eicosapentaenoic acid

Escherichia coli hemolysin (HlyA) is a prototype of a large family of pore-forming proteinaceous exotoxins that have been implicated in the pathogenetic sequelae of severe infection and sepsis, including development of acute lung injury. In the present study in rabbit alveolar macrophages (AMs), subcytolytic concentrations of purified HlyA evoked rapid synthesis of platelet-activating factor, with quantities approaching those in response to maximum calcium ionophore challenge. In parallel, large quantities of leukotriene (LT) B(4) and 5-, 8-, 9-, 12-, and 15-hydroxyeicosatetraenoic acid (HETE) were liberated from HlyA-exposed AMs depending on exogenous arachidonic acid (AA) supply. Coadministration of eicosapentaenoic acid (EPA) dose dependently suppressed generation of the proinflammatory lipoxygenase products LTB(4) and 5-, 8-, 9-, and 12-HETE in parallel with the appearance of the corresponding EPA-derived metabolites LTB(5) and 5-, 8-, 9-, and 12-hydroxyeicosapentaenoic acid (HEPE). At equimolar concentrations, EPA turned out to be the preferred substrate over AA for these AM lipoxygenase pathways, with the sum of LTB(5) and 5-, 8-, 9-, and 12-HEPE surpassing the sum of LTB(4) and 5-, 8-, 9-, and 12-HETE by >80-fold. In contrast, coadminstration of EPA did not significantly reduce HlyA-elicited generation of the anti-inflammatory AA lipoxygenase product 15-HETE. We conclude that AMs are sensitive target cells for HlyA attack, resulting in marked proinflammatory lipid mediator synthesis. In the presence of EPA, lipoxygenase product formation is shifted from a pro- to an anti-inflammatory profile.

The presence of a glycosyl phosphatidylinositol-anchored alpha-mannosidase in boar sperm

alpha-Mannosidase and beta-galactosidase were released from boar sperm into the medium by treatment with calcium ionophore A23187 or by 0.2% Brij-35/2% acetic acid. About half as much alpha-mannosidase activity as that in the acid extract was recovered by digestion with phosphatidylinositol-specific phospholipase C (PI-PLC), whereas the liberation rate of beta-galactosidase treated with PI-PLC was low. These results suggest that some alpha-mannosidase is anchored in the plasma membrane of the acrosomal region by attachment to the lipid phosphatidylinositol and that beta-galactosidase is localized mainly in the acrosome or integrated in the plasma membrane by a spanning stretch of hydrophobic peptides. beta-Galactosidase, which is present as an oligomers in the acid extract of sperm, dissociated into monomers under weakly alkaline conditions; under acidic conditions, the monomers associated again. No pH-sensitive association-dissociation of alpha-mannosidase was observed.

Synthesis of arachidonic acid-derived lipoxygenase and cytochrome P450 products in the intact human lung vasculature

Lipoxygenase (LO) and cytochrome P450 monooxygenase products of arachidonic acid (AA) have been implicated in a large number of vasoregulatory processes. In intact, blood-free, perfused and ventilated human lungs (n = 8), isolated during surgery for bronchial carcinoma, we analyzed leukotrienes (LTs), hydroxyeicosatetraenoic acids (HETEs), and epoxyeicosatrienoic acids (EETs) by sequential sampling of the recirculating buffer fluid. For the analysis we used multistep, solid-phase extraction, isocratic reversed-phase high-performance liquid chromatography, with elution of all metabolites within one run and photodiode array detection to obtain full UV spectra of eluting compounds. We detected no LT release in a 15-min baseline period, but the admixture of the calcium ionophore A23187 with the buffer fluid provoked the rapid appearance of all LTs. Some baseline release of 15-HETE was observed, and in response to A23187, maximum buffer concentrations were noted for 5-HETE, with 8-HETE, 9-HETE, 11-HETE, and 12-HETE being detected at lower levels. Marked baseline liberation of 11,12-EET and 8,9-EET was observed. In response to A23187, high oxirane buffer concentrations were registered, which far surpassed those of LTs and HETEs. The eicosanoid release was paralleled by a limited pulmonary artery pressor response and progressive vascular leakage. We conclude that ex-vivo-perfused human lungs release EETs > LTs > HETEs into the vascular compartment in response to inflammatory challenge. The marked oxirane synthesis in the lung vasculature may have major impact on lung vasoregulation when considering the possible function of these AA epoxides as endothelium-derived hyperpolarizing factors.

Prevention of corticosteroid-induced osteoporosis by alfacalcidol

We studied the effect of alphacalcidol (1-alpha-hydroxycholecalciferol) on bone metabolism in patients who were placed on glucocorticoid therapy. We selected 41 women (age: 32-52 yrs) who were recently diagnosed with systemic lupus erythematodes, multiple sclerosis, rheumatoid arthritis or asthma bronchiale. Patients did not have other disease or take drugs known to influence bone metabolism. Patients were randomly enrolled into two groups and were given 5-25 mg prednisone daily. After 4 weeks, group A (n = 21) received 0.5-1.0 microgram (mean = 0.54 +/- 0.03 microgram) alphacalcidol and group B (control; n = 20) was given 500 mg calcium daily for three years. There were no significant differences in age and steroid doses between groups. Serum calcium (Ca), osteocalcin (OC), collagen I C-terminal propeptide (PICP), parathyroid hormone (PTH), and urinary calcium and deoxypyridinoline crosslink excretion (DPD) were measured before corticosteroid administration, and before alphacalcidol or calcium treatment as well as 6 weeks, 6 months, and 1, 2, and 3 years later. Bone mineral density (BMD) was examined before treatment and 6 months, 1, 2, and 3 years later by DEXA and SPA. OC and PICP decreased significantly after 4 weeks on steroid in both groups and increased in group A but not in group B after 6 weeks of treatment with alphacalcidol and remained unchanged for 3 years. Serum PTH increased in both groups after 4 weeks of glucocorticoid treatment and was reduced in group A, but not in group B, after 6 weeks on alphacalcidol. Serum Ca, urinary Ca, and DPD did not change significantly in either group during the study period. Lumbar spine and femoral neck BMD were significantly reduced in group B after 6 months and 1 year, respectively, and continued to decrease during the study, while no significant change in group A was observed. BMD of the radius did not change in either group for 2 years but there was a significant reduction by the third year in group B. Based on these results, alphacalcidol treatment appears to be effective in preventing glucocorticoid-induced bone loss in these patients by reducing secondary hyperparathyroidism and stimulating bone formation.

First Report of Phyllachora ambrosiae in Europe Causing Epidemics on Common Ragweed

Common ragweed (Ambrosia artemisiifolia var. elatior (L.) Descourt.) was introduced to Europe from North America during the nineteenth century. Since the early 1990s, it has become the most widespread and most important allergenic weed in Hungary. In July 1999, during the annual survey of fungal diseases of ragweed in Hungary, plants exhibiting irregular brown spots surrounded by yellowish halos with small black spherical bodies on the upper surface of leaves, especially along the vessels, were collected from three roadside sites. Light microscopy revealed intracellular hyphae in the cells of leaf tissues, including the vessels, and perithecia (186 to 262 μm in diameter) containing paraphyses and asci (93 × 15 μm) with eight hyaline, unicellular ascospores (14 × 7.5 μm). Hyphae also were observed in asymptomatic leaf tissues and the petioles of infected plants. Mature perithecia commonly found in the necrotic spots also were present in asymptomatic, green leaf tissues. Based on the literature (1,2) and on the morphological examination of two herbarium specimens, BPI 636220 and BPI 636225, borrowed from the U.S. National Fungus Collection, the fungus was identified as Phyllachora ambrosiae (Berk. & M.A. Curtis) Sacc., a holobiotrophic pathogen of ragweed in North and South America. This is the first report of P. ambrosiae on ragweed in Europe. To confirm pathogenicity, leaves of five potted ragweed plants, grown from seed in pots, were inoculated with 0.1 ml of an aqueous suspension containing 5 × 10⁵ ascospores per ml. Inoculated plants were placed in a moist chamber for 48 h and kept in the greenhouse at 20 to 25°C. Noninoculated plants served as controls. Two weeks after inoculation, yellowish spots, which later became brown and necrotic, and perithecia appeared on each of the inoculated leaves. Infected leaves died 3 to 4 weeks after inoculation. Symptoms were similar to those seen in the field. The fungus in tissues of inoculated plants was morphologically identical to the original fungus on plants with spontaneous infections. Control plants did not develop symptoms. To determine the distribution of P. ambrosiae in Hungary, a total of 500 ragweed plants were collected at random from 21 locations in all regions of the country between August and October 1999. Symptoms characteristic of P. ambrosiae infections and perithecia of the fungus were found in 92% of all 500 collected plants. From mid-September, all ragweed plants examined had dead leaves and inflorescences. Perithecia of P. ambrosiae were found in leaves, stems, and flowers. References: (1) P. A. Saccardo. 1883. Sylloge Fungorum. Patavii (Padova), Sumptibus Aucteris. (2) F. Theissen and H. Sydow. 1915. Ann. Mycol. 13:431.

The effect of intravesical mitomycin C on the recurrence of superficial (Ta-T1) bladder cancer. A Hungarian Multicenter Study

We evaluated the prophylactic efficacy of instillations of intravesical mitomycin C in 57 patients with primary superficial bladder cancer in a multicenter clinical trial. After complete transurethral resection of Ta-T1 G1-G2 transitional cell bladder carcinomas, patients were treated with mitomycin 40 mg/50 ml saline of 15 instillations for 12 months. Most of the complications were mild and transient but two patients dropped out of the trial because of moderate side effects. Fifty-one patients were evaluable. We observed tumour recurrences in six patients (11.8%) during a median follow-up of 44.5 months. The recurrences were treated by transurethral resection. There was no muscle invasive progression in the recurrences. Our investigations confirm the effectiveness of mitomycin C in the treatment of patients with superficial bladder cancer.

PAF-induced synthesis of tetraenoic and pentaenoic leukotrienes in the isolated rabbit lung

In an isolated rabbit lung model, we tested the hypothesis that platelet-activating factor (PAF)-induced leukotriene (LT) synthesis is critically dependent on the free precursor fatty acid supply and the possible substitution of arachidonic acid (AA) by eicosapentaenoic acid (EPA). To augment the intravascular polymorphonuclear neutrophils (PMNs) in the isolated lung, human PMNs were infused into the pulmonary artery. LTs and hydroxyeicosatetra(penta)enoic acids were quantified with HPLC techniques. Application of PAF (5 microM) or AA (10 microM) provoked the generation of limited quantities of 4-series LTs and 5-hydroxyeicosatetraenoic acid (total sum of 5-lipoxygenase products approximately 7 and approximately 27 pmol/ml in lungs both with and without infused PMNs, respectively). Combined administration amplified 5-lipoxygenase product formation, with a predominance of cysteinyl-LT synthesis in lungs both without (total sum approximately 67 pmol/ml) and, much more strikingly, with (total sum approximately 308 pmol/ml) an infusion of neutrophils. EPA (10 microM) elicited exclusive generation of 5-series LTs and 5-hydroxyeicosapentaenoic acid (total sum approximately 82 pmol/ml). Dual stimulation with PAF and EPA provoked amplification of EPA-derived 5-lipoxygenase product formation, again with predominance of cysteinyl-LTs in lungs without (total sum approximately 224 pmol/ml) and, in particular, with (total sum approximately 545 pmol/ml) preceding microvascular PMN entrapment. Combined application of PAF, AA, and EPA resulted in the synthesis of LTs derived from both fatty acids, with a predominance of 5-series products. We conclude that the PAF-evoked 5-lipoxygenase product formation in the neutrophil-harboring lung capillary bed is critically dependent on intravascular precursor fatty acid supply, with EPA representing the preferred substrate compared with AA. PMN-related transcellular eicosanoid synthesis is suggested to underlie the predominant generation of cysteinyl-LTs. The supply of n-3 versus n-6 precursor fatty acid may thus have a major impact on inflammatory mediator generation.

Staphylococcal alpha-toxin provokes coronary vasoconstriction and loss in myocardial contractility in perfused rat hearts: role of thromboxane generation

BACKGROUND

Cardiac performance is severely depressed in septic shock. Endotoxin has been implicated as the causative agent in Gram-negative sepsis, but similar abnormalities are encountered in Gram-positive sepsis. We investigated the influence of the major exotoxin of Staphylococcus aureus, staphylococcal alpha-toxin, in isolated perfused rat hearts.

METHODS AND RESULTS

Alpha-toxin 0.25 to 1 microg/mL caused a dose-dependent increase in coronary perfusion pressure that more than doubled. In parallel, we noted a decrease in left ventricular developed pressure and the maximum rate of left ventricular pressure rise (dP/dt(max)), dropping to a minimum of <60% of control. These changes were accompanied by a liberation of thromboxane A(2) and prostacyclin into the coronary effluent. The release of creatine kinase, lactate dehydrogenase, potassium, and lactate did not surpass control heart values, and leukotrienes were also not detected. Indomethacin, acetylsalicylic acid, and the thromboxane receptor antagonist daltroban fully blocked the alpha-toxin-induced coronary vasoconstrictor response and the decrease in left ventricular developed pressure and dP/dt(max), whereas the lipoxygenase inhibitor nordihydroguaiaretic acid, the platelet activating factor antagonist WEB 2086, and the alpha-adrenergic antagonist phentolamine were entirely ineffective. Inhibition of nitric oxide synthase even enhanced the alpha-toxin-induced increase in coronary perfusion pressure and the loss in myocardial performance.

CONCLUSIONS

Purified staphylococcal alpha-toxin provokes coronary vasoconstriction and loss in myocardial contractility. The responses appear to be largely attributable to the generation of thromboxane and are even enhanced when the endogenous nitric oxide synthesis is blocked. Bacterial exotoxins, such as staphylococcal alpha-toxin, may thus be implicated in the loss of cardiac performance encountered in Gram-positive septic shock.

Cytochrome P450 2C is an EDHF synthase in coronary arteries

In most arterial beds a significant endothelium-dependent dilation to various stimuli persists even after inhibition of nitric oxide synthase and cyclo-oxygenase. This dilator response is preceded by an endothelium-dependent hyperpolarization of vascular smooth muscle cells, which is sensitive to a combination of the calcium-dependent potassium-channel inhibitors charybdotoxin and apamin, and is assumed to be mediated by an unidentified endothelium-derived hyperpolarizing factor (EDHF). Here we show that the induction of cytochrome P450 (CYP) 2C8/34 in native porcine coronary artery endothelial cells by beta-naphthoflavone enhances the formation of 11,12-epoxyeicosatrienoic acid, as well as EDHF-mediated hyperpolarization and relaxation. Transfection of coronary arteries with CYP 2C8/34 antisense oligonucleotides results in decreased levels of CYP 2C and attenuates EDHF-mediated vascular responses. Thus, a CYP-epoxygenase product is an essential component of EDHF-mediated relaxation in the porcine coronary artery, and CYP 2C8/34 fulfils the criteria for the coronary EDHF synthase.

Potassium-dependent changes in the conformation of the Kv2.1 potassium channel pore

The voltage-gated K+ channel, Kv2.1, conducts Na+ in the absence of K+. External tetraethylammonium (TEAo) blocks K+ currents through Kv2.1 with an IC50 of 5 mM, but is completely without effect in the absence of K+. TEAo block can be titrated back upon addition of low [K+]. This suggested that the Kv2.1 pore undergoes a cation-dependent conformational rearrangement in the external vestibule. Individual mutation of lysine (Lys) 356 and 382 in the outer vestibule, to a glycine and a valine, respectively, increased TEAo potency for block of K+ currents by a half log unit. Mutation of Lys 356, which is located at the outer edge of the external vestibule, significantly restored TEAo block in the absence of K+ (IC50 = 21 mM). In contrast, mutation of Lys 382, which is located in the outer vestibule near the TEA binding site, resulted in very weak (extrapolated IC50 = approximately 265 mM) TEAo block in the absence of K+. These data suggest that the cation-dependent alteration in pore conformation that resulted in loss of TEA potency extended to the outer edge of the external vestibule, and primarily involved a repositioning of Lys 356 or a nearby amino acid in the conduction pathway. Block by internal TEA also completely disappeared in the absence of K+, and could be titrated back with low [K+]. Both internal and external TEA potencies were increased by the same low [K+] (30-100 microM) that blocked Na+ currents through the channel. In addition, experiments that combined block by internal and external TEA indicated that the site of K+ action was between the internal and external TEA binding sites. These data indicate that a K+-dependent conformational change also occurs internal to the selectivity filter, and that both internal and external conformational rearrangements resulted from differences in K+ occupancy of the selectivity filter. Kv2.1 inactivation rate was K+ dependent and correlated with TEAo potency; as [K+] was raised, TEAo became more potent and inactivation became faster. Both TEAo potency and inactivation rate saturated at the same [K+]. These results suggest that the rate of slow inactivation in Kv2.1 was influenced by the conformational rearrangements, either internal to the selectivity filter or near the outer edge of the external vestibule, that were associated with differences in TEA potency.

Modulation of N-type Ca2+ channels by intracellular pH in chick sensory neurons

Both physiological and pathological neuronal events, many of which elevate intracellular [Ca2+], can produce changes in intracellular pH of between 0.15 and 0.5 U, between pH 7.4 and 6.8. N-type Ca2+ channels, which are intimately involved in exocytosis and other excitable cell processes, are sensitive to intracellular pH changes. However, the pH range over which N-type Ca2+ channels are sensitive, and the sensitivity of N-type Ca2+ channels to small changes in intracellular pH, are unknown. We studied the influence of intracellular pH changes on N-type calcium channel currents in dorsal root ganglion neurons, acutely isolated from 14-day-old chick embryos. Intracellular pH was monitored in patch-clamp recordings with the fluorescent dye, BCECF, and manipulated in both the acidic and basic direction by extracellular application of NH4+ in the presence and absence of intracellular NH4+. Changes in intracellular pH between 6.6 and 7.5 produced a graded change in Ca2+ current magnitude with no apparent shift in activation potential. Intracellular acidification from pH 7.3 to 7.0 reversibly inhibited Ca2+ currents by 40%. Acidification from pH 7.3 to pH 6.6 reversibly inhibited Ca2+ currents by 65%. Alkalinization from pH 7.3 to 7.5 potentiated Ca2+ currents by approximately 40%. Channels were sensitive to pHi changes with high intracellular concentrations of the Ca2+ chelator, bis-(o-aminophenoxy)-N,N,N',N'-tetraacetic acid, which indicates that the effects of pHi did not involve a Ca2+-dependent mechanism. These data indicate that N-type Ca2+ channel currents are extremely sensitive to small changes in pHi in the range produced by both physiological and pathological events. Furthermore, these data suggest that modulation of N-type Ca2+ channels by pHi may play an important role in physiological processes that produce small changes in pHi and a protective role in pathological mechanisms that produce larger changes in pHi.