Functional, biochemical and molecular biological evidence for a possible beta(3)-adrenoceptor in human near-term myometrium

The possible existence of a beta(3)-adrenoceptor (beta(3)-AR) in human near-term myometrium was investigated by in vitro functional and biochemical studies and analysis of mRNA expression. SR 59119A and SR 59104A and CGP 12177 (two selective agonists and a partial agonist, respectively, of the beta(3)-AR), salbutamol and terbutaline (beta(2)-AR agonists) each produced a concentration-dependent relaxation of the myometrial spontaneous contractions. There were no differences in pD(2) values for the relaxing potencies of terbutaline, salbutamol, CGP 12177 and SR 59119A. The rank order for their relaxing efficacies was SR 59119A>SR 59104A>terbutaline approximately salbutamol approximately CGP 12177 (E(max)=52+/-7%, 42+/-12% and approximately 30% respectively). Propranolol, a beta(1)- and beta(2)-AR antagonist, and ICI 118551, a beta(2)-AR antagonist (both at 0.1 microM), did not affect the SR 59119A-induced relaxation whereas SR 59230A, a selective beta(3)-AR antagonist (1 microM), significantly reduced the maximal relaxing effect of SR 59119A. SR 59119A and salbutamol induced a significant increase in cyclic AMP levels that was antagonized by SR 59230A but not by propranolol for SR 59119A, and by propranolol but not by SR 59230A for salbutamol. The beta(3)-AR mRNA was positively expressed in myometrium preparations in a reverse transcription polymerase chain assay. The results presented provide the first evidence for the existence of the beta(3)-AR subtype in human near-term myometrium and suggest that the effects of SR 59119A might be mediated through an increase in cyclic AMP level.

Pulsed electromagnetic field stimulation of MG63 osteoblast-like cells affects differentiation and local factor production

Pulsed electromagnetic field stimulation has been used to promote the healing of chronic nonunions and fractures with delayed healing, but relatively little is known about its effects on osteogenic cells or the mechanisms involved. The purpose of this study was to examine the response of osteoblast-like cells to a pulsed electromagnetic field signal used clinically and to determine if the signal modulates the production of autocrine factors associated with differentiation. Confluent cultures of MG63 human osteoblast-like cells were placed between Helmholtz coils and exposed to a pulsed electromagnetic signal consisting of a burst of 20 pulses repeating at 15 Hz for 8 hours per day for 1, 2, or 4 days. Controls were cultured under identical conditions, but no signal was applied. Treated and control cultures were alternated between two comparable incubators and, therefore, between active coils; measurement of the temperature of the incubators and the culture medium indicated that application of the signal did not generate heat above the level found in the control incubator or culture medium. The pulsed electromagnetic signal caused a reduction in cell proliferation on the basis of cell number and [3H]thymidine incorporation. Cellular alkaline phosphatase-specific activity increased in the cultures exposed to the signal, with maximum effects at day 1. In contrast, enzyme activity in the cell-layer lysates, which included alkaline phosphatase-enriched extracellular matrix vesicles, continued to increase with the time of exposure to the signal. After 1 and 2 days of exposure, collagen synthesis and osteocalcin production were greater than in the control cultures. Prostaglandin E2 in the treated cultures was significantly reduced at 1 and 2 days, whereas transforming growth factor-beta1 was increased; at 4 days of treatment, however, the levels of both local factors were similar to those in the controls. The results indicate enhanced differentiation as the net effect of pulsed electromagnetic fields on osteoblasts, as evidenced by decreased proliferation and increased alkaline phosphatase-specific activity, osteocalcin synthesis, and collagen production. Pulsed electromagnetic field stimulation appears to promote the production of matrix vesicles on the basis of higher levels of alkaline phosphatase at 4 days in the cell layers than in the isolated cells, commensurate with osteogenic differentiation in response to transforming growth factor-beta1. The results indicate that osteoblasts are sensitive to pulsed electromagnetic field stimulation, which alters cell activity through changes in local factor production.

Pyrazinamide is not active against Mycobacterium tuberculosis residing in cultured human monocyte-derived macrophages

SETTING

Mycobacteriology Laboratory, National Jewish Medical and Research Center, Denver, Colorado.

OBJECTIVE

To evaluate the antimicrobial activity of pyrazinamide against Mycobacterium tuberculosis in cultured human monocyte-derived normal and activated macrophages.

DESIGN

Monocytes separated from human blood were incubated in plastic plates for seven days to mature into macrophage monolayers. After activation with TNF-alpha or IFN-gamma or without prior treatment, the macrophages were infected with M. tuberculosis. Various concentrations of pyrazinamide (PZA), morphazinamide (MZA) or isoniazid (INH) were added the next day, and the viable counts of the intracellular bacteria were determined at days 0, 4, and 8.

RESULTS

No inhibitory activity of PZA at any concentration was detected, while clear dose-dependent bacteriostatic and bactericidal activities were demonstrated by MZA and INH in the same experimental model.

CONCLUSIONS

PZA has neither bacteriostatic nor bactericidal activity against M. tuberculosis persisting or multiplying in cultured monocyte-derived human macrophages, and it might be that the well-known effectiveness of this drug in tuberculosis patients is not related to its supposed activity against intracellular bacterial subpopulations.

Luteinizing hormone response to controlled-release deslorelin in estradiol benzoate primed ovariectomized gilts

Development of a controlled release formulation of gonadotropin releasing hormone that would stimulate a LH surge capable of reducing the time span of ovulations would greatly benefit reproductive management because a single timed insemination could be used. A dose-response study was conducted to determine if Deslorelin, a potent gonadotropin releasing hormone analogue, delivered via the SABER system, a biodegradable controlled release system, would stimulate an ovulatory-like LH surge in the pig. Twenty ovariectomized gilts, approximately 200 d old and 100 kg body weight (BW), received estradiol benzoate (15 microg/kg BW im) and 48 h later, the gilts were given deslorelin at 0, 12.5, 25.0, 50.0 or 100.0 microg im (n = 4 each treatment group). Compared to controls, mean blood deslorelin concentrations were still elevated at 30 h after deslorelin. Mean deslorelin magnitude, area under the curve and duration were sequentially greater (P<0.05) in a dose-dependent sequence. Compared to controls, serum LH concentrations were elevated (P<0.05) for 6 to 12 h after deslorelin. A dose-response relationship was absent for all parameters of LH secretion. Magnitude of the serum LH response was greatest (P<0.05) in the 12.5 microg and 50.0 microg groups, whereas area under the curve was lower (P<0.05) after 25.0 microg of deslorelin than after 12.5, 50.0 and 100.0 microg, which were not different from each other. Thus, no more than 12.5 microg of deslorelin is necessary to obtain maximum LH release in the model studied and doses less than 12.5 microg may also be effective.

Restenosis after percutaneous coronary interventions and infection

Infectious agents may directly or indirectly (through the response of the host's immune system) modulate the growth of vascular cells. Local and/or systemic increase of cytokines could influence the extent of (re-)stenosis in the vascular tree. Further studies in this field may identify patients at a high risk for atherogenesis and restenosis. Their results should be helpful in treating restenosis after percutaneous coronary interventions.

Strategies to optimize CAD prevention in modern cardiology. The "Marburg CAD Prevention Project"

In recent years we identified numerous cardiovascular risk factors and had been able to reduce cardiovascular events by a variety of different interventions. There is no question that we can improve the course of coronary artery disease (CAD) in patients with a high-risk profile by modifying these factors. Despite this knowledge, many patients with known CAD or myocardial infarction are not treated for secondary prevention as recommended by well established guidelines (http:¿www.chd-taskforce.com). In order to improve secondary prevention in our patients we started a project, the so called "Marburg CAD Prevention Project". By this we combine our computer data base of the CAD preventional routine laboratory with the computer program CARDDAS. Individual risk factors and the angiographic findings were analyzed. Patients as well as local physicians were informed on the need to treat the important risk factors. This approach ensures that at least all of our patients with documented CAD receive the appropriate preventional recommendations and treatment.

The double negative effect: the (almost) paradoxical role of the individual self in minority and majority members' information processing

The authors examined the interactive influence of accessibility of the individual self and relative in-group size on group-level as opposed to individual-level information processing. In Expt 1, the authors predicted and found that, when accessibility of the individual self was low, minority members tended more towards group-level information processing than did majority members. This was not true when accessibility of the individual self was high. Contrary to the authors' hypothesis, however, the disappearance of the minority-majority effect in the high-accessibility condition did not result from a decrease in group-level information processing among minority members, but from an increase among majority members. Experiment 2 replicated this unexpected effect using two different measures of group level information processing. It also provided additional data on the dynamic interplay of the individual self and the collective self which seems to be responsible for the observed effects.

Effects of pulsed electromagnetic fields on bone healing in a rabbit tibial osteotomy model

OBJECTIVE

The purpose of this study was to determine the effect of pulsed electromagnetic field (PEMF) exposure on healing tibial osteotomies in New Zealand White rabbits.

DESIGN

One-millimeter Gigli saw osteotomies were stabilized by external fixation. One day after surgery, rabbits were randomly assigned to receive either no exposure (sham control) or thirty minutes or sixty minutes per day of low-frequency, low-amplitude PEMF. Radiographs were obtained weekly throughout the study. Rabbits were euthanized at fourteen, twenty-one, or twenty-eight days, and tibiae underwent either destructive torsional testing or histologic analysis. To determine the baseline torsional strength and stiffness of rabbit tibiae, eleven normal intact tibiae were tested to failure.

RESULTS

Sixty-minute PEMF-treated osteotomies had significantly higher torsional strength than did sham controls at fourteen and twenty-one days postoperatively. Thirty-minute PEMF-treated osteotomies were significantly stronger than sham controls only after twenty-one days. Normal intact torsional strength was achieved by fourteen days in the sixty-minute PEMF group, by twenty-one days in the thirty-minute PEMF group, and by twenty-eight days in the sham controls. Maximum fracture callus area correlated with the time to reach normal torsional strength.

CONCLUSION

In this animal model, low-frequency, low-amplitude PEMF significantly accelerated callus formation and osteotomy healing in a dose-dependent manner.

Cytochrome P-450 2E1 activity and oxidative stress in alcoholic patients

As cytochrome P-450 2E1 (CYP2E1) induction was related to oxidative stress in experimental models, the aim of this study was to investigate the relationship between CYP2E1 activity and markers of oxidative stress in 40 alcoholic patients entering a rehabilitation programme. Plasma oxidized proteins, lipid peroxides (LPO) and antibodies against hydroxyethyl radical (HER) or malondialdehyde (MDA) adducts were assessed as markers of the production of free radicals, whereas vitamin E levels were evaluated as a marker of the antioxidant defence. CYP2E1 activity was determined by using the 6-hydroxychlorzoxazone:chlorzoxazone blood metabolic ratio, 2 h after drug intake. This ratio was increased by 4-fold in alcoholics, compared to non-alcoholic patients, and was correlated with daily intake of ethanol, carbohydrate-deficient transferrin, and blood alcohol level at the time of admission to hospital. Plasma levels of LPO and oxidized proteins were slightly increased (20%) in alcoholic patients when compared with the control group, whereas those of vitamin E were found to be slightly decreased (by 18%). Antibodies against HER or MDA adducts showed a very significant increase. However, when alcoholic patients were divided into two groups according to low or high CYP2E1 induction, no significant difference was observed in the variation of these parameters, except for anti-HER adducts antibodies. Therefore, our study confirms the main involvement of CYP2E1 in HER production. By contrast, CYP2E1 does not appear to be the main factor responsible for the oxidative stress occurring during human chronic alcoholism. Free radicals from other sources may therefore contribute significantly to the generation of this oxidative stress.

Effect of faradic products on direct current-stimulated calvarial organ culture calcium levels

Calcium release from mouse calvarial organ cultures was used to analyse the well-described biological effects of constant direct current (20 microA) in combination with Faradic products generated at a titanium wire cathode. Constant 20-microA direct current stimulation alone, delivered by agar salt bridges, consistently lowered the media calcium levels. Direct exposure of calvariae to a titanium cathode and its faradic products resulted in further lowering of media calcium levels and also a significant increase in the media pH. Hydrogen peroxide is a faradic product of the titanium cathode, micromolar amounts being generated by our system over 24 hr. H(2)O(2) is pro-resorptive whereas elevated pH stimulates osteoblast activity. We propose that where bone tissue is in direct contact with metal wire cathodes, the faradic products, hydrogen peroxide and hydroxyl ion, are significant factors which, in their own right, further contribute to accelerated remodelling and improved clinical outcome.

Analysis of beta-catenin gene mutations in pancreatic tumors

BACKGROUND/AIM

Mutations of the adenomatous polyposis coli (APC) tumor suppressor gene have been described in a subset of pancreatic carcinomas. The APC gene modulates the beta-catenin-Tcf pathway. The major player in this pathway is the beta-catenin protein encoded by the beta-catenin gene. A variety of different tumors, including colon, prostate, endometrial, and hepatocellular carcinomas, carry mutations in exon 3 of the beta-catenin gene. The aim of this study was to determine the role of the beta-catenin gene in the genesis of exocrine and endocrine tumors of the pancreas.

METHODS

78 ductal pancreatic adenocarcinomas, 14 ductal pancreatic cancer cell lines, and 33 endocrine pancreatic tumors were evaluated for mutations in exon 3 of the beta-catenin gene by single-strand conformation polymorphism analysis and direct DNA sequencing. In addition, 40 ductal pancreatic adenocarcinomas were analyzed for intracellular beta-catenin accumulation by immunohistochemistry, indicating alterations of the beta-catenin gene.

RESULTS

Neither the 111 exocrine and endocrine pancreatic tumors nor the 14 pancreatic cancer cell lines carried mutations in exon 3 of the beta-catenin gene. Intracellular beta-catenin accumulation was not identified in any of the 40 pancreatic adenocarcinomas.

CONCLUSION

These data suggest that the beta-catenin gene as the major player of the beta-catenin-Tcf pathway does not play an important role in the genesis of pancreatic tumors.

Requirement for omega and (omega;-1)-hydroxylations of fatty acids by human cytochromes P450 2E1 and 4A11

Human liver microsomes and recombinant human P450 have been used as enzyme source in order to better understand the requirement for the optimal rate of omega and (omega;-1)-hydroxylations of fatty acids by cytochromes P450 2E1 and 4A. Three parameters were studied: alkyl chain length, presence and configuration of double bond(s) in the alkyl chain, and involvement of carboxylic function in the fatty acid binding inside the access channel of P450 active site. The total rate of metabolite formation decreased when increasing the alkyl chain length of saturated fatty acids (from C12 to C16), while no hydroxylated metabolite was detected when liver microsomes were incubated with stearic acid. However, unsaturated fatty acids, such as oleic, elaidic and linoleic acids, were omega and (omega;-1)-hydroxylated with an efficiency at least similar to palmitic acid. The (omega;-1)/omega ratio decreased from 2.8 to 1 with lauric, myristic and palmitic acids as substrates, while the reverse was observed for unsaturated C18 fatty acids which are mainly omega-hydroxylated, except for elaidic acid showing a metabolic profile quite similar to those of saturated fatty acids. The double bond configuration did not significantly modify the ability of hydroxylation of fatty acid, while the negatively charged carboxylic group allowed a configuration energetically favourable for omega and (omega;-1)-hydroxylation inside the access channel of active site.

Effect of filgrastim treatment on inflammatory cytokines and lymphocyte functions

Twenty-four healthy male volunteers received either placebo or 75, 150, or 300 microg filgrastim (recombinant methionyl human granulocyte colony-stimulating factor) for 12 days to study effects on monocytes and lymphocytes. In all filgrastim-treated groups, tumor necrosis factor alpha (TNF-alpha), interleukin-12 (IL-12), and interferon gamma (IFN-gamma) release by whole blood in response to endotoxin (lipopolysaccharide) was reduced. IL-12 added in vitro to lipopolysaccharide-stimulated blood of filgrastim-treated donors restored IFN-gamma and TNF-alpha release, suggesting that the anti-inflammatory effect of granulocyte colony-stimulating factor is exercised through IL-12 suppression. Phytohemagglutinin- or anti-CD3 antibody-induced lymphocyte proliferation ex vivo was reduced by 60% from day 5 to day 15, after a 50% increase at day 2 with concomitant doubled IL-2 release. In vivo, filgrastim induced doubling of all T-cell populations by day 8. Filgrastim decreased proinflammatory cytokine production and lymphocyte proliferation ex vivo throughout prolonged treatment at all doses. This indicates that endogenous granulocyte colony-stimulating factor may counterregulate the inflammatory cytokine cascade and implies a potential indication for filgrastim in chronic inflammatory conditions.

Ethnic susceptibility to lung cancer: differences in CYP2E1, CYP1A1 and GSTM1 genetic polymorphisms between French Caucasian and Chilean populations

Many investigators have reported an association between genetic polymorphisms of cytochromes P-450 CYP2E1, CYP1A1 or glutathione S-transferase Mu (GSTM1) and susceptibility to lung cancer. However, pronounced interethnic variations have been described in the frequencies of these polymorphisms, especially between Asians and Caucasians. The present study was set up to establish CYP2E1 (c1, c2 and C, D), CYP1A1 (m1, m2 and Ile, Val) and GSTM1 (null) allelic frequencies in Chileans (n = 96) who are an admixture of Native Americans and Caucasians (Spaniards). The rare allele frequencies were found to be 0.15 (c2), 0.21 (C), 0.23 (m2), 0.32 (Val) and 0.21 ('null' genotype). These values are significantly higher than those of Caucasians except for the GSTM1 'null' genotype and suggest differences in susceptibility to lung cancer between both populations.

Inhibition of mitochondrial ATP generation by nitric oxide switches apoptosis to necrosis

Under pathological conditions, the mode of cell death, apoptosis or necrosis, is relevant for the subsequent fate of the tissue. Cell demise may be shaped by endogenous mediators such as nitric oxide (NO) which interfere with subroutines of the death program. Here we show that apoptosis of Jurkat cells elicited by either staurosporine (STS) or anti-CD95 antibodies in glucose-free medium is converted to necrosis by NO donors. In the presence of NO, release of mitochondrial cytochrome c was delayed and activation of execution caspases was prevented. Stimulated cells died nonetheless. The switch in the mode of cell death was due to NO-dependent failure of mitochondrial energy production. Restoration of intracellular ATP by glucose supplementation recovered the cells' ability to activate caspases and undergo apoptosis. In this system, the apoptosis/necrosis conversion promoted by NO was not mediated by cyclic guanosine monophosphate-dependent mechanisms, poly-(ADP-ribose)-polymerase (PARP) activation, or inhibition of caspases due to S-nitrosylation and glutathione depletion. In contrast, depleting intracellular ATP with rotenone, an inhibitor of mitochondrial complex I mimicked the effect of NO. The findings presented here suggest that NO can decide the shape of cell death by lowering intracellular ATP below the level required to allow the coordinated execution of apoptosis.

Higher frequency of DPC4/Smad4 alterations in pancreatic cancer cell lines than in primary pancreatic adenocarcinomas

The tumor suppressor gene DPC4/Smad4 at 18q21.1 is inactive in about 50% of pancreatic carcinoma xenografts and cell lines. However, the role of DPC4 in the multistep carcinogenesis of primary pancreatic adenocarcinomas remains uncertain. Therefore, we examined 45 primary human pancreatic adenocarcinomas and 12 pancreatic cancer cell lines for DPC4 alterations by single-strand conformational variant (SSCV) analysis and a PCR-based deletion assay. DPC4 was inactivated by either homozygous deletion or point mutation in 6 of 12 cell lines (50%). None of the primary pancreatic carcinomas carried a DPC4 mutation, although 66% revealed LOH of 18q21 sequences. These findings suggest that inactivation of DPC4 occurs more frequently in tumor-derived cell lines than in primary pancreatic adenocarcinomas. In addition, another, yet unidentified, tumor suppressor gene(s) may be linked with the frequent LOH of 18q21 in primary pancreatic adenocarcinomas.

Nitric oxide inhibits execution of apoptosis at two distinct ATP-dependent steps upstream and downstream of mitochondrial cytochrome c release

The endogenous mediator nitric oxide (NO) blocked apoptosis of Jurkat cells elicited by staurosporine, anti-CD95 or chemotherapeutics, and switched death to necrosis. The switch in the mode of cell death was dependent on the ATP loss elicited by NO. This affected two distinct steps of the apoptotic cascade. First, the release of cytochrome c from mitochondria was delayed by NO. Second, processing of procaspases-3/7 to the active proteases was prevented even after cytochrome c had been released. Thus, NO interferes with execution steps of apoptosis both upstream and downstream of cytochrome c release.

Mutations of the DPC4/Smad4 gene in neuroendocrine pancreatic tumors

Tumors of the endocrine pancreas are extremely rare, and molecular mechanisms leading to their development are not well understood. A candidate tumor suppressor gene, DPC4, located at 18q21, has recently been shown to be inactivated in half of pancreatic adenocarcinoma xenografts. The close anatomical relationship of the exocrine and endocrine pancreas prompted us to determine the role of DPC4 in the tumorigenesis of 25 pancreatic islet cell tumors (11 insulinomas, nine non-functioning endocrine carcinomas, three gastrinomas, two vipomas). A mutation screening of the highly conserved COOH-terminal domain of DPC4 (exons 8-11) was performed by single-strand conformational variant (SSCP) analysis and a PCR-based deletion assay. Five of nine (55%) non-functioning endocrine pancreatic carcinomas revealed either point mutations, small intragenic deletions or homozygous deletion of DPC4 sequences compared to none of the insulinomas, gastrinomas or vipomas. These results suggest that DPC4 is an important target gene promoting tumorigenesis of non-functioning neuroendocrine pancreatic carcinomas.

Signal selection in high-resolution NMR by pulsed field gradients

We describe a new and powerful computer program called TRIPLE GRADIENT which calculates optimized pulsed field gradient sequences for specific coherence pathway selection or rejection. Sequences can be computed for gradient coils acting along one, two, or three perpendicular axes. The program is based on the computational minimization of a penalty function formed from the summed amplitudes of the unwanted signals. The underlying mathematical analysis makes use of a vectorial representation of the way in which a gradient sequence suppresses different signals. It is argued that experiments using well-calculated gradient sequences are quicker and generally perform better than those using extensive phase cycling, especially when suppressing extremely strong solvent signals, and it is shown that in many cases gradient experiments of optimal signal-to-noise ratio can be performed. These claims are illustrated by spectra obtained from an HQQC experiment.

[Laboratory diagnosis in preventive cardiology]

In recent years a large number of coronary artery disease risk factors were discovered. The knowledge of these factors improves the estimate of the coronary artery disease (CAD) risk--however it still remains to be only an "estimate". A perfect prediction of an upcoming CAD event is not possible, despite all high score laboratory technology. Therefore the use of specialized laboratory procedures should be applied carefully. Knowing the blood levels of cholesterol, triglycerides, HDL- and LDL-cholesterol and Lp(a) can be sufficient for many therapeutical decisions. Severe dyslipidemia, familial CAD and CAD without any obvious reasons demand a more specialized work-up, however, risk stratification factors such as family history, clinical history (CAD, hypertension, diabetes mellitus, smoker) and genetics are crucial, apart from the above mentioned laboratory values. Purely on the basis of the lipidologic baseline concentrations we can't give well based recommendations for the treatment of individual patients. Currently there are expert systems available which allow a risk estimate once important laboratory values (LDL cholesterol, HDL cholesterol, Triglycerides) as well as clinical data (blood pressure, family history, clinical history) are available. This system can be accessed by internet under "http:/(/)www.chd-taskforce.com".

[Germline mutations in the MEN1 gene: basis for predictive genetic screening and clinical management of multiple endocrine neoplasia type 1 (MEN1) families]

BACKGROUND AND OBJECTIVE

Mutations in the MEN 1 gene were recently discovered as the causative genetic defect of the autosomal dominantly inherited multiple endocrine neoplasia type 1. It was the aim of this study to evaluate the spectrum of MEN 1 mutations in our own series of patients in order to obtain a basis for predictive family screening.

PATIENTS AND METHODS

Genomic DNA from peripheral blood of 21 patients with MEN 1, members of 14 non-related MEN 1 families, was examined for MEN 1 germ-line mutations by means of single-strand conformation variant analysis (SSCP) and direct DNA sequencing. In addition, blood from 20 asymptomatic family members of five families was tested for its predictive value.

RESULTS

Eleven different heterozygotic germ-line mutations, among them eight frameshift, two missense and one nonsense mutations, were identified. In four of the 20 asymptomatic members from five MEN 1 families who had been tested after appropriate genetic counselling, the MEN 1 mutation characteristic for the particular family was found. Clinical screening programme in three mutation carriers revealed abnormal findings in all three: one primary hyperparathyroidism, one prolactinoma and one nonfunctioning pancreatic tumour each. The 16 family members without MEN 1 mutation were spared further unnecessary screening investigations.

CONCLUSION

Although the function of the MEN 1 gene is not yet known, molecular genetic tests provide a basis for genetic counselling, predictive genetic screening and clinical management of MEN 1 families.

Interferon-inducible Mx proteins in fish

Mx proteins are members of a family of interferon-inducible genes expressed when cells are treated with double-stranded RNA or virus infection. These proteins are important components of the antiviral response and form the first line of the body's defense against virus infections. The exact mechanism of action for these proteins has not been discovered, but mice missing the Mx genes are extremely sensitive to influenza virus infection. Mammals have between two and three Mx genes whose functions may vary with regard to the inhibition of a specific virus, cellular localization, and activity. The cDNA of three rainbow trout Mx proteins has been cloned and a comparison of their sequences with that of avian and mammalian species reveals striking conservation of domains. They all maintain the tripartite ATP/GTP binding domain and the dynamin family signature in the amino terminal half of the protein. In the carboxyl terminal half of the Mx proteins are the localization signals and the leucine zipper motifs which account for the trimerization of Mx in the cell. Like the rat and human Mx proteins, the different trout Mx proteins exhibit distinctly different immunohistochemical staining patterns in cells transfected with plasmids expressing RBTMx1, RBTMx2, or RBTMx3. To date, the antiviral function of the trout Mx proteins has not been satisfactorily established.

MEN1 gene mutations in 12 MEN1 families and their associated tumors

Multiple endocrine neoplasia type 1 (MEN1) is an autosomal dominant inherited tumor syndrome characterized by the development of multiple endocrine tumors. The gene responsible for the disease, termed MEN1 gene. has recently been isolated and germline mutations have been described in affected MEN1 individuals. Twelve unrelated (German MEN1 families and their associated tumors (5 parathyroid tumors, 1 vipoma, 1 gastrinoma, 1 insulinoma) were characterized for MEN1 gene mutations by single-strand conformational variant (SSCV) analysis and DNA sequence analysis as well as for loss of heterozygosity on chromosome 11q13. We identified nine different heterozygous germline mutations (6 frameshift, 2 missense, 1 nonsense), eight of them were novel. Four of five informative MEN1-associated tumors revealed deletion of the second MEN1 allele, supporting the concept of a tumor suppressor gene. Furthermore. SSCV analysis proved an effective and sensitive method for the detection of menin mutations providing a reliable genetic screening approach supporting genetic counseling and clinical management of MEN1 family members.

Pulsed electromagnetic fields simultaneously induce osteogenesis and upregulate transcription of bone morphogenetic proteins 2 and 4 in rat osteoblasts in vitro

Pulsed electromagnetic fields (PEMF) are successfully employed in the treatment of a variety of orthopaedic conditions, particularly delayed and nonunion fractures. In this study, we examined PEMF effects on in vitro osteogenesis by bone nodule formation and on mRNA expression of bone morphogenetic proteins 2 and 4 by reverse-transcriptase polymerase chain reaction (RT-PCR) in cultured rat calvarial osteoblasts. PEMF exposure induced a significant increase in both the number (39% over unexposed controls) and size (70% larger compared to unexposed controls) of bone-like nodules formed. PEMF also induced an increase in the levels of BMP-2 and BMP-4 mRNA in comparison to controls. This effect was directly related to the duration of PEMF exposure. This study shows that clinically applied PEMF have a reproducible osteogenic effect in vitro and simultaneously induce BMP-2 and -4 mRNA transcription. This supports the concept that the two effects are related.

Liquid chromatography-mass spectrometry and gas chromatography-mass spectrometry of omega- and (omega-1)-hydroxylated metabolites of elaidic and oleic acids in human and rat liver microsomes

In order to characterize the nature of the active site of cytochrome P450 2E1, the metabolism of various fatty acids with cis/trans geometric configurations has been investigated. A system coupling atmospheric pressure chemical ionization-mass spectrometry detection with HPLC separation was developed as an alternative method for the characterization of hydroxylated metabolites of oleic and elaidic acids in rat and human liver microsomes. Oxidation of oleic and elaidic acids led to the formation of two main metabolites which were identified by LC-MS and GC-MS as omega and (omega-1)-hydroxylated (or 17-OH and 18-OH) fatty acids, on the basis of their pseudo-molecular mass and their fragmentation. The assay was accurate and reproducible, with a detection limit of 25 ng per injection, a linear range from 25 to 1128 ng per injection, no recorded interference, intra-day and inter-day precision with variation coefficients <14%. This LC-MS method was validated with oleic acid by using both radiometric and mass spectrometric detections. A significant correlation was found between the two methods in human (r=0.86 and 0.94 with P<0.05 and 0.01) and rat liver microsomes (r=0.90 and 0.85 with P<0.01 and 0.05) for 17-OH and 18-OH metabolites, respectively. HPLC coupled to mass spectrometry for the analysis of hydroxylated metabolites of elaidic acid offers considerable advantages since the method does not require use of a radioactive molecule, completely separates the two hydroxymetabolites, confirms the identification of each metabolite, and is as sensitive as the radiometric analysis method. This method allowed the comparative study of oleic and elaidic acid hydroxylations by both human and rat liver microsomal preparations.

On-demand treatment of gastro-oesophageal reflux symptoms: a comparison of ranitidine 75 mg with cimetidine 200 mg or placebo

AIM

To compare the effects of ranitidine 75 mg with those of either cimetidine 200 mg or placebo given on demand for relief of typical symptoms of gastro-oesophageal reflux disease during a 15-day period.

METHODS

A total of 1336 patients (aged > or = 18 years) with heartburn episodes were recruited and randomly assigned to a ranitidine 75 mg, cimetidine 200 mg or placebo group. Depending on the occurrence or persistence of heartburn, treatment was administered as required up to three times daily, with at least 2 h between drug doses. Antacids were allowed as rescue medication if symptoms persisted for at least 2 h after the third medication on any given day. The primary end-point was defined as the proportion of patients with relief of at least 75% of heartburn episodes during the study period (i.e. relief occurring within 2 h after drug ingestion and lasting for at least 5 h).

RESULTS

Analysis was performed in an intention-to-treat population comprising 504 subjects in the ranitidine group, 515 in the cimetidine group and 270 in the placebo group. Primary end-point success rates were 41, 38 and 28%, respectively, for the three groups (P < 0.001 for ranitidine vs. placebo, P = 0.274 for ranitidine vs. cimetidine). Ranitidine 75 mg was significantly more effective than placebo in providing overall heartburn relief (P < 0.001). The differences between the ranitidine and cimetidine groups were not significant, except for a greater reduction in heartburn frequency in the ranitidine group at the end of the study period (P < 0.05). Drug dose was lower and less rescue medication was used in the ranitidine group than the placebo group. The three treatment groups did not differ in terms of tolerability.

CONCLUSION

On-demand ranitidine 75 mg or cimetidine 200 mg are safe and effective treatment for reflux-related symptoms.

Large artery remodeling during aging: biaxial passive and active stiffness

To examine arterial mechanical changes during aging, pressure-radius and axial force-radius curves were measured in vivo in carotid arteries from 6- and 23-month-old Brown Norway X Fischer 344 rats. Incremental passive circumferential stiffness (measured at 50, 100, and 200 mm Hg) was higher (P<0.01) in the 23- compared with the 6-month-old rats (14.02+/-1.23 versus 6.58+/-1.51; 2.68+/-0.56 versus 0.99+/-0.34; 1.10+/-0.24 versus 0.69+/-0.15 dyne/mm2x10(3), respectively). Incremental passive axial stiffness was increased (P<0.01) in the 23- compared with the 6-month-old rats (7.95+/-0.70 versus 4.24+/-0.81; 1.91+/-0.10 versus 0.61+/-0.16; 0.58+/-0.09 versus 0.36+/-0.06 dyne/mm2x10(3), respectively). Active incremental circumferential arterial stiffness at 100 and 200 mm Hg was increased (P<0.01) in the older rats. In 6-month-old rats, activation of vascular smooth muscle enhanced (P<0.01) the incremental circumferential and axial stiffness measured at 200 mm Hg. In 23-month-old rats, only active incremental stiffness was increased (P<0.01) at 200 mm Hg. Aging increased (P<0.05) media thickness, collagen content, and the collagen/elastin ratio by 12%, 21%, and 38%, respectively. Elastin density and the number of smooth muscle cell nuclei were decreased by 20% and 31%, respectively, with aging. Thus, structural alterations that occur with aging are associated with changes in both active and passive stiffness. Vascular smooth muscle tone modulates arterial wall anisotropy differently during aging.

Determination of Structure of Aggregates by Confocal Scanning Laser Microscopy

The fractal dimension of a particle aggregate can provide fundamental information on the structure and origin of the aggregate. The analysis of large chemically homogeneous fractal objects has been achieved, but reliable methods of estimating the fractal dimensions of large and chemically heterogeneous aggregates are needed. To this end, we used confocal scanning laser microscopy in which thin optical sections of aggregates were obtained in order to calculate their 2D and ultimately 3D fractal dimensions according to the Mandelbrot theory. Fractal dimensions of 2.08 +/- 0.11 for a Brownian aggregation of latex particles and 2.25 +/- 0.12 for shear aggregation were determined using the confocal technique. These values are within the ranges for universality classes predicted for such aggregates and observed by previous investigators. Thus, this method appears to provide reliable estimates of the fractal dimension with particular utility in the characterization of aggregates composed of larger particles or complex materials where the fractal dimension may not be accessible by light-scattering measurements. The confocal method is used to analyze flocs of activated sludge material as one example of the application of this method to more complex, large (up to 500 µm), and chemically heterogeneous flocs. Copyright 1998 Academic Press.

Heteronuclear relaxation study of the PH domain of beta-spectrin: restriction of loop motions upon binding inositol trisphosphate

The structural dynamics of protein ligand binding sites is one factor determining the specificity towards related ligands. In this context, the spectrin PH domain, which binds to a number of phosphatidylinositol lipid head groups, was investigated with respect to the dynamics of the binding loops. The latter were found to be of intermediate flexibility on a picosecond to nanosecond time-scale in the free protein and become more rigid upon ligand binding. Significant 15N and proton chemical shift changes occur in the binding loops. The internal correlation time, determined from 15N heteronuclear relaxation data using the standard model-free approach, decreases upon ligand binding. For several residues a concomitant rise in the generalized order parameter is observed. This is interpreted as a dampening effect of the ligand on a slow loop motion, while a fast component is not affected. Molecular dynamics simulations were performed to further investigate this situation. In fact, two time-scales of loop motions in the free state are observed in a 9 ns molecular dynamics trajectory. Agreement with generalized order parameters obtained from the experiment improves when a subtrajectory is analyzed that excludes rare dihedral transitions.

Keratinocyte growth factor protects murine hepatocytes from tumor necrosis factor-induced apoptosis in vivo and in vitro

Keratinocyte growth factor (KGF) promotes epithelial growth and differentiation and has potent effects on the liver. The coinjection of lipopolysaccharide (LPS) and D-galactosamine (GalN) results in hepatic failure in mice. Mechanistically, LPS-induced tumor necrosis factor (TNF) triggers hepatocyte apoptosis, which is enhanced by GalN-arrested transcription. Similarly, the combination of TNF and actinomycin D (ActD) causes hepatocyte apoptosis in vitro. We studied the effect of KGF on LPS and GalN-induced hepatic failure in vivo and on TNF- and ActD-induced hepatocyte apoptosis in vitro, where it was compared with those of hepatic growth factor (HGF) and epidermal growth factor (EGF). Mice treated with human recombinant KGF (1 mg/kg subcutaneously) 24 hours before intraperitoneal coinjection of LPS and GalN sustained prolonged survival compared with control mice, although overall mortality was not changed. The counts of apoptotic hepatocytes, serum alanine and aspartate transaminases, and DNA fragments in the cytosolic fraction of liver homogenates were higher in control mice than in treated mice 6 hours after LPS and GalN coinjection, before any mortality occurred. In vitro, hepatocytes pretreated with KGF exhibited reduced TNF- and ActD-induced cell damage and DNA fragmentation, similar to hepatocytes pretreated with HGF and EGF. In conclusion, KGF prolongs survival during LPS- and GalN-induced hepatic failure by temporarily protecting hepatocytes against apoptosis. It also protects hepatocytes in vitro against TNF- and ActD-induced apoptosis.

[The action of the proton pump inhibitor pantoprazol against acetylsalicylic acid-induced gastroduodenopathy in comparison to ranitidine. An endoscopic controlled, double blind comparison]

In a randomised double-blind parallel study the gastroduodenal tolerability of 300 mg acetylsalicilic acid daily (ASA, CAS 50-78-2) has been evaluated in the presence of placebo (n = 8), 40 mg pantoprazole (CAS 102625-70-7) daily (8 a.m.) (n = 16) and 300 mg ranitidine (CAS 66357-35-5) daily (8 a.m.) (n = 16) in healthy volunteers using upper GI-endoscopy. The treatment period lasted 14 days, endoscopic controls were performed at entry and repeated at day 14. At entry, the mean endoscopic score averaged 1.0 +/- 0.0 (+/- SEM) in the ASA/placebo, in the ASA/pantoprazole and the ASA/ranitidine group. In the placebo experiments 300 mg ASA daily induced marked gastroduodenal lesions at day 14 (lesion score of 6.8 +/- 1.4 (+/- SEM). Concomitant administration of 40 mg pantoprazole daily offered significant protection against 300 mg ASS daily on day 14 (2.1 +/- 0.6) (+/- SEM) (p < 0.05) vs ASA/placebo. 300 mg ASA plus 300 mg ranitidine daily reduced the damaging score to 4.9 +/- 1.2 (+/- SEM) (n.s. vs ASA/ placebo). Our data suggest that coadministration of 40 mg pantoprazole daily reduces significantly gastroduodenal lesions evoked by 300 mg ASA daily.

Frequent abnormalities of the putative tumor suppressor gene FHIT at 3p14.2 in pancreatic carcinoma cell lines

The FHIT gene is localized on chromosome 3p14, a region including a tumor cell-specific, commonly deleted region. To determine the role of the FHIT gene in pancreatic carcinogenesis, 14 pancreatic carcinoma cell lines were analyzed by reverse transcription-PCR and exon-specific PCR amplification of genomic DNA. The full-length FHIT transcript was lost in 70% of the pancreatic carcinoma cell lines analyzed, while 66% also revealed intragenic homozygous deletions of exons 3, 4, and 5. Truncated FHIT transcripts lacking a variable number of exons most likely represented alternative splicing products. Fhit protein expression was dependent on a full-length FHIT transcript. The results suggest that the FHIT gene may be a target tumor suppressor gene involved in pancreatic carcinogenesis.

Immunological and biological properties of Bet v 4, a novel birch pollen allergen with two EF-hand calcium-binding domains

We have isolated a cDNA clone coding for a birch pollen allergen, Bet v 4. The deduced amino acid sequence of Bet v 4 contained two typical EF-hand calcium-binding domains. Sequence similarities of Bet v 4 to calmodulin are primarily confined to the calcium-binding domains. However, significant sequence similarities extending outside the Ca2+-binding sites were found with a recently described group of pollen-specific allergens of Brassica and Bermuda grass. Both EF-hand domains of Bet v 4 are able to bind Ca2+, as demonstrated by 45Ca2+ blot overlay of wild type and calcium-binding deficient mutants of Bet v 4. Among pollen-allergic patients, protein-bound Ca2+ was not an absolute requirement for IgE recognition of Bet v 4. However, disruption of the carboxyl-terminal Ca2+-binding domain indicated that most IgE antibodies from allergic patients are directed against this site. IgE inhibition experiments suggested that Bet v 4 represents a highly cross-reactive pollen allergen. Pre-absorption of allergic sera with Bet v 4 drastically reduced IgE binding to proteins of similar molecular weight in pollen extracts from distantly related plant species (e.g. timothy grass, mugwort, lily) but not in extracts from plant-derived foodstuff. To test for a possible biological role in pollen germination and tube growth, we introduced recombinant Bet v 4 protein into growing lily pollen tubes by iontophoresis. As a result, cytoplasmic streaming stopped in the vicinity of the electrode tip, and a slight depolarization of the membrane voltage was measured. These effects were not observed with Ca2+-binding deficient mutants of Bet v 4. Thus, Bet v 4 and homologous proteins represent a new class of pollen-specific Ca2+-binding allergens that may have a physiological role as inhibitors of cytoplasmic streaming in outgrowing pollen tubes.

ZBP-89, a Krüppel-type zinc finger protein, inhibits cell proliferation

ZBP-89 is a Krüppel-type zinc finger transcription factor that binds to GC-rich sequences. Overexpression of this factor prevents EGF induction of the gastrin promoter; therefore, we postulated that ZBP-89 may modulate cellular proliferation. To test this hypothesis, ZBP-89 was overexpressed in immortalized (GH4) and malignant (AGS) cell lines. Growth parameters, e.g., 3H-thymidine, BrdU labeling, flow cytometry and ornithine decarboxylase promoter activity were analyzed. The results show that DNA synthesis is inhibited and progression to S phase is blocked in GH4 cells. Collectively, these studies demonstrate that ZBP-89 inhibits cellular proliferation at least in part through its ability to bind and repress ornithine deacarboxlyase promoter activity.

When self-categorization makes sense: the role of meaningful social categorization in minority and majority members' self-perception

The authors examined the joint influence of meaningful social categorization and relative in-group size on the depersonalization of self-perception. Meaningfulness of social categorization was varied following the fit principle, introduced by self-categorization theory. In Experiment 1, the authors predicted and found that minority members show more depersonalized self-perception than majority members if, and only if, the meaningfulness of the underlying in-group-out-group categorization is high as opposed to low. Experiment 2 further substantiated that a meaningful social categorization affects only minority members' self-perception. Finally, the conceptual relationship between fit, meaning, and identity is discussed.

RAP1-like binding activity in islet cells corresponds to members of the Sp1 family of transcription factors

Deletion and mutational analyses of the gastrin promoter have identified a binding site for the yeast transcription factor RAP1 relevant for transcriptional activation in islet cells. We here report that the mammalian transcription factors binding to this site in islet cells are the Sp transcription factor members Sp1 and Sp3. Furthermore, functional analyses revealed Sp1- and Sp3-mediated transcriptional activation of gastrin. These data reveal that the zinc finger proteins Sp1 and Sp3 do have similar binding specificities as the multifunctional yeast RAP1 protein.