Xenon-129 MR imaging and spectroscopy of rat brain using arterial delivery of hyperpolarized xenon in a lipid emulsion

Hyperpolarized (129)Xe dissolved in a lipid emulsion constitutes an NMR tracer that can be injected into the blood stream, enabling blood-flow measurement and perfusion imaging. A small volume (0.15 ml) of this tracer was injected in 1.5 s in rat carotid and (129)Xe MR spectra and images were acquired at 2.35 T to evaluate the potential of this approach for cerebral studies. Xenon spectra consistently showed two resonances, at 194.5 ppm and 199.0 ppm relative to the gas peak. The signal-to-noise ratio (SNR) obtained for the two peaks was sufficient (ranging from 12 to 90) to follow their time courses. 2D transverse-projection xenon images were obtained with an in-plane resolution of 900 microm per pixel (SNR range 8-15). Histological analysis revealed no brain damage except in two rats that had received three injections.

Further evidence for linkage of low-mid frequency hearing impairment to the candidate region on chromosome 4p16.3

We have investigated a three-generation family with an autosomal dominant low-mid frequency hearing loss. Audiograms show consistently a hearing threshold of 50+/-20 db hearing loss (HL) between 250 Hz and 1-2 kHz. Normal hearing level was reached between 3 and 6 kHz in all examined children. Adult patients show an additional hearing impairment (HI) in the mid and higher frequencies that seems to differ from presbyacusis. The HI is always bilateral and symmetrical. Genes causing non-syndromic autosomal-dominant deafness with HI in the low and mid frequencies were previously mapped to chromosome 4p16.3 (DFNA6, DFNA14) and chromosome 5q31 (DFNA1). After exclusion of linkage to DFNA1 on chromosome 5, we mapped the candidate gene region to the DFNA14 and DFNA6 loci, between the genetic markers D4S432 and D4S431, located on chromosome 4. This is a further family in which evident linkage of low-mid frequency HI to the candidate region on chromosome 4p16.3 has been found.

High-resolution structure of HLA-A*0201 in complex with a tumour-specific antigenic peptide encoded by the MAGE-A4 gene

The heterotrimeric complex of the human major histocompatibity complex (MHC) molecule HLA-A*0201, beta2-microglobulin and the decameric peptide GVYDGREHTV derived from the melanoma antigen (MAGE-A4 protein has been determined by X-ray crystallography at 1.4 A resolution. MAGE-A4 belongs to a family of genes that are specifically expressed in a variety of tumours. MAGE-A4-derived peptides are presented by MHC molecules at the cell surface to cytotoxic T-lymphocytes. As the HLA-A*0201:MAGE-A4 complex occurs only on tumour cells, it is considered to be an appropriate target for immunotherapy. The structure presented here reveals potential epitopes specific to the complex and indicates which peptide residues could be recognised by T-cell receptors. In addition, as the structure could be refined anisotropically, it was possible to describe the movements of the bound peptide in more detail.

High glycolytic activity in rat glioma demonstrated in vivo by correlation peak 1H magnetic resonance imaging

High-grade brain tumors are known to have a high rate of glucose (Glc) consumption. Postmortem measurements have suggested that Glc content in experimental brain tumors is relatively low. We used magnetic resonance spectroscopy to investigate this, in vivo, in the brains of seven rats bearing intracerebral C6 gliomas. We combined the high spectral resolution allowed by two-dimensional proton nuclear magnetic resonance with spatial encoding by magnetic field gradient pulses to obtain in vivo maps of Glc, alanine, hypotaurine, aspartate, phosphoethanolamine, Glu/Gln, N-acetylaspartate (NAA), phosphocreatine/creatine (PCr/Cr), choline-containing compounds, and lactate (Lac) (some of which are involved in energy metabolism). Compared with normal brain tissue, the main differences found in the gliomas were that Glc, NAA, PCr/Cr, and aspartate concentrations were much lower, whereas concentrations of alanine, hypotaurine, phosphoethanolamine, and Lac were higher, whatever the extent of necrosis. A striking observation is the similarity of the NAA and Glc images: the concentrations of both metabolites are lower in the tumor than they are in the contralateral brain. If Glc was completely absent from the tumor tissue, and if the residual Glc level was due only to a partial volume effect like that for NAA, a neuronal marker, the ratio [Glc]tumor/[Glc]contralateral tissue, should be similar to that found for NAA. The ratio for Glc was 0.48 +/- 0.22 (+/- SD; n = 6), a ratio similar to that found for PCr/Cr (0.50 +/- 0.19) but significantly higher than that obtained for NAA (0.29 +/- 0.07). This observation indicates that a measurable Glc concentration is still present in the tumor tissue. Intense glycolysis in tumor cells may explain the increased production of Lac and alanine and decreased amount of Glc. These nuclear magnetic resonance measurements of metabolite concentrations are complementary to positron emission tomography, which measures Glc consumption.

Multipoint development of the weighted pairwise correlation (WPC) linkage method for pedigrees of arbitrary size and application to the analysis of breast cancer and alcoholism familial data

The weighted pairwise correlation (WPC) method is a simple and powerful model-free method of linkage analysis that has the advantages of being applicable to binary, ordered categorical, quantitative, or censored traits, and to consider all pairs of relatives in large pedigrees. The originally implemented approach was limited to the use of the identical by state (IBS) information, and we recently extended the WPC method to incorporate the identical by descent (IBD) information for two-point linkage analysis. Here, we develop a multipoint WPC method suitable for pedigrees of arbitrary size and large number of markers. The multipoint IBD estimation procedure for relative pairs is based on the efficient regression approach developed for pedigrees implemented in SOLAR. A robust and fast Monte-Carlo procedure is used to determine reliable P values. Application of the method to the 214 pedigrees from the Breast Cancer Linkage Consortium provided for the Genetic Analysis Workshop (GAW) 9 shows that multipoint WPC statistic values were not far from two-point maximum lod-score values obtained by the classical parametric linkage method and were higher than multipoint variance component analysis lod-scores obtained with SOLAR. The multipoint WPC method is also used to analyze the familial Collaborative Study of the Genetics of Alcoholism data on alcoholism released for GAW11. It allows a better specification of the linkage results previously obtained within the chromosome 4 region.

Pharmacological investigation on nigrescigenin-a cardenolide from Parquetina nigrescens (Afzel.) Bullock: comparative studies on cardiotonic effects of Parquetina nigrescens, g-strophanthin and noradrenaline in guinea-pig isolated atria

The cardiotonic and catecholamine-like effects of Parquetina nigrescens extract-induced contractile force of guinea-pig left and right atria were investigated in-vitro. Isometric contractions were recorded. P. nigrescens extract, 5-150 microg mL(-1), increased the force of contraction dose dependently in electrically driven left atria. The concentration of P. nigrescens extract producing 50% of the maximal effect (EC50 value) was 7.5 microg mL(-1). The positive inotropic response differed from that of g-strophanthin by its high rate of onset and its complete reversibility upon removal of the extract from the incubation medium. In spontaneously beating right atrial muscle, P. nigrescens extract increased the rate of contractions. Its positive chronotropic and inotropic effects were partly antagonized by propranolol and atenolol indicating the presence of an adrenergic acting principle in P. nigrescens extract. In contrast, the inotropic response to P. nigrescens extract could not be completely suppressed by beta-blocking agents, suggesting that the force of contraction is not only increased by a sympathomimetic ingredient of P. nigrescens extract but also by the cardenolides known to be present in P. nigrescens.

Pharmacokinetics of morphine 3-esters after oral administration in rabbits

Pharmacokinetics of three morphine 3-esters-3-(2,2-dimethylvaleroyl) morphine (A), 3-(2-phenylbenzoyl) morphine (B), and 3-(2,2-diphenylpropionyl) morphine (C) was characterized after single oral administration in rabbits. Blood was sampled up to 24 h and cerebro-spinal fluid (CSF) was collected with the last blood sample. The concentration of the morphine 3-esters, morphine, morphine 3-glucuronide and morphine 6-glucuronide were determined in plasma and CSF using HPLC UV-detection. The morphine 3-esters were suggested to be a subject to marked presystemic elimination, since, in comparison to the administration of the un-esterified morphine, relatively low concentrations of morphine and morphine glucuronides were detected in plasma. The rate of disposition of morphine was dependent on the hydrolytic stability of the esters. The mean (+/- S.E.) plasma half-life of morphine was 0.9 +/- 0.2 h, 2.5 +/- 0.6 h and 3.5 +/- 3.5 h after the administration of A, B and C, respectively, compared to 0.9 +/- 0.2 h as estimated after the administration of non-esterified morphine. An analgesic effect will be achieved, since morphine was detected in CSF even 24 h after the application of the ester pro-drugs. It is concluded that esterification at the 3-position may be adapted to obtain sustained plasma levels of morphine.

Genesis of the ILT/LIR/MIR clusters within the human leukocyte receptor complex

The human leukocyte receptor complex (LRC) contains at least 26 genes which belong to the immunoglobulin superfamily The genes include two clusters of immunoglobulin-like transcript (ILT)/leukocyte immunoglobulin-like receptor (LIR)/monocyte-macrophage inhibitory receptor (MIR) loci, a cluster of killer cell inhibitory receptor (KIR) genes, two leukocyte-associated immunoglobulin-like receptor genes, as well as the Fc receptor for IgA and the natural cytotoxicity receptor I loci. It has already been postulated that these genes have evolved by multiple duplications, while the two ILT clusters are likely to have been generated by the inverse duplication of an ancient ILT cluster. To shed more light on the possible origin of the loci within the LRC, we have now investigated the presence of KIR and ILT loci in a variety of vertebrates by hybridizations and compared the genomic sequences of all ILT genes. Our results lead to the following conclusions: 1) the origin of KIR genes dates back to about 100 million years, but only primate and human KIRs are closely related; 2) in contrast, genes which are detectable with human ILT cDNAs are already found in birds, suggesting their presence already about 300 million years ago. Using the sequence data produced by the human genome project, we have developed a hypothesis that reconstructs the genesis of the two human ILT clusters in detail which will help to understand the function of the LRC.

Systematic screening for mutations in the human necdin gene (NDN): identification of two naturally occurring polymorphisms and association analysis in body weight regulation

BACKGROUND

NDN, which codes for the human necdin protein, is a candidate gene for Prader-Willi syndrome (PWS). One feature of this neurogenetic disorder is hyperphagia resulting in extreme obesity observed later in development.

OBJECTIVE AND DESIGN

In this study we have used single-strand conformation polymorphism (SSCP) analysis to identify sequence variants at the human necdin gene. Furthermore we tested whether these variants were associated with obesity in extremely obese German children and adolescents.

RESULTS

Two gene variants could be identified: a g.1352T-->C polymorphism in the putative promotor region and a silent g.2311C-->T polymorphism in the coding region. Genotype and allele frequency distribution of both of the polymorphisms were not significantly different between lower and higher body mass index (BMI) subjects.

CONCLUSIONS

Hence, it is unlikely that these polymorphisms play a major role in the emergence of juvenile onset human obesity.

Rat lung MRI using low-temperature prepolarized helium-3

The purpose of this study was to evaluate the recently proposed technique of 3He prepolarization at low temperature and high field (Kober et al. Magn Reson Med 1999; 41:1084-1087) for fast imaging of the lung. Helium-3 was cooled to 2.4 K in a magnetic field of 8 Tesla to obtain a polarization of 0.26%. The polarized 3He was warmed up to room temperature and transferred to a rat, with a final polarization of about 0.1%, large enough for acquiring a 3D image of the rat lung in 30 s.

Characterization of clustered MHC-linked olfactory receptor genes in human and mouse

Olfactory receptor (OR) loci frequently cluster and are present on most human chromosomes. They are members of the seven transmembrane receptor (7-TM) superfamily and, as such, are part of one of the largest mammalian multigene families, with an estimated copy number of up to 1000 ORs per haploid genome. As their name implies, ORs are known to be involved in the perception of odors and possibly also in other, nonolfaction-related, functions. Here, we report the characterization of ORs that are part of the MHC-linked OR clusters in human and mouse (partial sequence only). These clusters are of particular interest because of their possible involvement in olfaction-driven mate selection. In total, we describe 50 novel OR loci (36 human, 14 murine), making the human MHC-linked cluster the largest sequenced OR cluster in any organism so far. Comparative and phylogenetic analyses confirm the cluster to be MHC-linked but divergent in both species and allow the identification of at least one ortholog that will be useful for future regulatory and functional studies. Quantitative feature analysis shows clear evidence of duplications of blocks of OR genes and reveals the entire cluster to have a genomic environment that is very different from its neighboring regions. Based on in silico transcript analysis, we also present evidence of extensive long-distance splicing in the 5'-untranslated regions and, for the first time, of alternative splicing within the single coding exon of ORs. Taken together with our previous finding that ORs are also polymorphic, the presented data indicate that the expression, function, and evolution of these interesting genes might be more complex than previously thought.

At receptor inhibition affects the noradrenaline sensitivity in isolated portal vein of normotensive rat

Short term treatments of normotensive Wistar Kyoto rats with angiotensin II (ANGII) or in combination with the AT1 receptor antagonist, losartan or PD123319, the AT2 receptor antagonist on systemic arterial blood pressure (MABP) and their influence on noradrenaline sensitivity in isolated mesenteric portal vein were evaluated. ANGII increased MABP as well as the contractile response to noradrenaline in vessels from ANGII-treated animals. MABP and the maximal effect of the concentration response curve for noradrenaline were prevented by losartan. However, PD123319 did not influence the blood pressure, but completely removed the vessels sensitivity to noradrenaline. ANGII combined with the AT1 and/or AT2 receptors blockade completely prevented the pressure response to ANGII, but the concentration response curve for noradrenaline did not differ from the vehicle-treated control curve. In conclusion both AT1- and AT2 receptor activation seems to be important in controlling noradrenaline sensitivity of rat portal vein smooth muscle.

Activity of a novel bcl-2/bcl-xL-bispecific antisense oligonucleotide against tumors of diverse histologic origins

BACKGROUND

Increased expression of the anti-apoptotic proteins Bcl-2 and Bcl-xL is involved in the development and progression of many tumors. We recently reported that the bcl-2/bcl-xL-bispecific antisense oligonucleotide 4625 induces apoptosis in lung carcinoma cells. To further assess the therapeutic potential of oligonucleotide 4625, we investigated its effect on a series of human tumor cell lines of diverse histologic origins in vitro and in vivo.

METHODS

Oligonucleotide 4625-mediated inhibition of bcl-2 and bcl-xL expression in vitro was measured in breast carcinoma cells with the use of reverse transcription-polymerase chain reaction (PCR), real-time PCR, and western blotting. Cytotoxicity was assessed in several different cell lines by measurement of tumor cell growth, propidium iodide uptake, and nuclear apoptosis. The in vivo activity of oligonucleotide 4625 was determined by the inhibition of growth of established tumor xenografts in nude mice, immunohistochemical staining of Bcl-2 and Bcl-x proteins in the tumors, and western blotting of tumor lysates. Apoptosis in tumor xenografts was detected with the use of in situ TUNEL (i.e., terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-digoxigenin nick end labeling) staining. All statistical tests are two-sided.

RESULTS

In breast carcinoma cells, oligonucleotide 4625 treatment reduced bcl-2 and bcl-xL messenger RNA levels in a dose-dependent manner. At 600 nM:, oligonucleotide 4625 reduced Bcl-2 and Bcl-xL protein levels to 25% (95% confidence interval [CI] = 16% to 34%) and 20% (95% CI = 14% to 26%), respectively, of the levels in untreated cells and it decreased viability in all cell lines mainly by inducing apoptosis. In vivo, oligonucleotide 4625 statistically significantly inhibited the growth of breast and colorectal carcinoma xenografts by 51% (95% CI = 28% to 74%) and 59% (95% CI = 44% to 74%), respectively, relative to those treated with control oligonucleotide 4626; it also reduced Bcl-2 and Bcl-xL protein levels and induced tumor cell apoptosis.

CONCLUSION

The bcl-2/bcl-xL-bispecific antisense oligonucleotide 4625 merits further study as a novel compound for cancer therapy.

Identification of human epidermal differentiation complex (EDC)-encoded genes by subtractive hybridization of entire YACs to a gridded keratinocyte cDNA library

The epidermal differentiation complex (EDC) comprises a large number of genes that are of crucial importance for the maturation of the human epidermis. So far, 27 genes of 3 related families encoding structural as well as regulatory proteins have been mapped within a 2-Mb region on chromosome 1q21. Here we report on the identification of 10 additional EDC genes by a powerful subtractive hybridization method using entire YACs (950_e_2 and 986_e_10) to screen a gridded human keratinocyte cDNA library. Localization of the detected cDNA clones has been established on a long-range restriction map covering more than 5 Mb of this genomic region. The genes encode cytoskeletal tropomyosin TM30nm (TPM3), HS1-binding protein Hax-1 (HAX1), RNA-specific adenosine deaminase (ADAR1), the 34/67-kD laminin receptor (LAMRL6), and the 26S proteasome subunit p31 (PSMD8L), as well as five hitherto uncharacterized proteins (NICE-1, NICE-2, NICE-3, NICE-4, and NICE-5). The nucleotide sequences and putative ORFs of the EDC genes identified here revealed no homology with any of the established EDC gene families. Whereas database searches revealed that NICE-3, NICE-4, and NICE-5 were expressed in many tissues, no EST or gene-specific sequence was found for NICE-2. Expression of NICE-1 was up-regulated in differentiated keratinocytes, pointing to its relevance for the terminal differentiation of the epidermis. The newly identified EDC genes are likely to provide further insights into epidermal differentiation and they are potential candidates to be involved in skin diseases and carcinogenesis that are associated with this region of chromosome 1. Moreover, the extended integrated map of the EDC, including the polymorphic sequence tag site (STS) markers D1S1664, D1S2346, and D1S305, will serve as a valuable tool for linkage analyses.

[Determination of pravastatin in rat liver by RP-HPLC]

AIM

To establish a reverse-phase high performance liquid chromatographic method for the determination of pravastatin in rat liver.

METHODS

An aliquot of 5 g liver homogenates, spiked with triamcinolone acetonide (internal standard), was extracted by solid-phase extraction with Bond Elut C18 columns. Chromatography was performed using a C18 reverse-phase column with mobile phase of Na2HPO4 buffer sdution (0.035 mmol.L-1, pH 3.0)-acetonitrile (155:42).

RESULTS

The linear equation was Y = 0.1843X-4.238 x 10(-3) (gamma = 0.9934) in the range of 0.05-10 micrograms.g-1 liver. The limit of detection for pravastatin was 13 ng.mL-1 (signal-to-noise ratio of 3), and the limit of quantification for pravastatin in liver homogenate was 50 ng.g-1 liver (RSD < 20%). The average extraction recovery of pravastatin from liver at different concentrations was 80.8%, and the average inter-day precision was 11%. This procedure was applied to assay pravastatin in rat liver which were collected from Lewis rats at different times after administration of pravastatin (ig 20 mg.kg-1).

CONCLUSION

The method was sensitive and is feasible for the pharmacokinetic and distribution study of pravastatin.

Genetic susceptibility and severity of alopecia areata in human and animal models

Alopecia areata (AA) is a non-scarring, inflammatory form of hair loss. Human and animal model observations suggest that AA is an autoimmune mediated disease. Genetic influence has been clearly demonstrated in many other autoimmune diseases and one would expect that AA is no exception. AA in rodent models involves genetic susceptibility and it is possible to cross breed the AA phenotype to unrelated rodent strains. Segregation analysis of rodent breeding programs suggests the involvement of several dominant and secondary genes. The increased frequency of AA in genetically related individuals, suggests that human AA expression also involves genetic susceptibility. Within the general population, AA does not segregate as a Mendelian, monogenic trait. AA is a continuous trait with varying degrees of hair loss within the affected population. This suggests that human AA expression involves a complex interaction of multiple genes. AA is most likely a polygenic disease where several, potentially identifiable, major genes affect disease susceptibility and minor severity modifying genes may further affect the phenotype. Here we review the literature on humans and animal models for AA to identify data in support of AA as a polygenic, multivariate penetrance disease with a threshold level for disease onset. Genome wide allelic association screening of animal models and genetically related human sibling pairs may be a suitable approach to identifying susceptibility and severity modifying genes for AA.

Molecular characterization of V-type H(+)-ATPase (B-subunit) in gills of euryhaline crabs and its physiological role in osmoregulatory ion uptake

The vacuolar-type H(+)-ATPase (V-ATPase) has been implicated in osmoregulatory ion uptake across external epithelia of a growing variety of species adapted to life in fresh water. In the present study, we investigated whether the V-ATPase may also function in a euryhaline species that tolerates brackish water (8 salinity) but not fresh water, the shore crab Carcinus maenas. cDNA coding for the regulatory B-subunit of the V-ATPase was amplified and sequenced from C. maenas gills and partially sequenced from four other crab species. Two isoforms differing in the 3′-untranslated region were found in C. maenas. In this species, the abundance of B-subunit mRNA was greater in the respiratory anterior gills than the ion-transporting posterior gills and was not increased by acclimation to dilute salinity. Immunocytochemical analysis showed that the B-subunit protein is not targeted to the apical membrane but is distributed throughout the cytoplasmic compartment. Physiological studies of isolated perfused gills indicated that the V-ATPase inhibitor bafilomycin had no effect on transepithelial potential difference. Thus, in contrast to the freshwater-tolerant Chinese crab Eriocheir sinensis, in which the V-ATPase appears to play an important osmoregulatory role, the V-ATPase in C. maenas probably functions in acidification of intracellular organelles but not in transbranchial NaCl uptake.

Familial associations of lipid profiles: a generalized estimating equations approach

Elevated plasma levels of apolipoproteins A1 (apoA1) and B (apoB) are important protective factors and risk factors, respectively, for atherosclerosis and coronary heart disease. It is well known that both apoA1 and apoB reveal strong familial aggregation. Our goal was to investigate whether exogenous variables influence these associations. We used marginal regression models for the mean and association structure (generalized estimating equations 2; GEE2) to analyse data from 1435 family members within 469 families of different sizes included in the Donolo-Tel Aviv Three-Generation Offspring Study. The usual robust variance matrix was approximated by extensions of jack-knife estimators of variance to GEE2 models. Estimation of standard errors in models with quite complex correlation structures was possible using this approach. All analyses were easily carried out using a menu-driven stand-alone software tool for marginal regression modelling. We demonstrate that a variety of hypotheses can be tested using Wald statistics by modelling regression matrices for the association structure. We show that correlation for apoB between parent-offspring pairs increased with decreasing age difference and that pairs with individuals of the same gender had more similar apoA1 levels than individuals of different gender. Associations between different relative pairs did not all agree with those expected from differences in kinship coefficients. The analysis using GEE2 models revealed structures that would not have been detected by other models and should therefore be used in addition to traditional approaches of analysing family data. GEE2 should be considered a standard method for the investigation of familial aggregation.

Effects of potassium channel inhibitors on the relaxation induced by the nitric oxide donor diethylamine nitric oxide in isolated human cerebral arteries

OBJECT

The goal of this study was to investigate whether K+ channels are involved in nitric oxide (NO)-induced relaxation of isolated human cerebral arteries.

METHODS

Successive concentration-response curves relating to the use of the NO donor diethylamine NO (DEA/NO) were established in the absence and presence of different K+ channel inhibitors after mounting human cerebral arteries onto a wire myograph. The arteries were obtained from macroscopically intact tissue that had been removed during brain tumor operations. A high K+ concentration partially inhibited the relaxant effects of DEA/NO. Different K+ channel inhibitors (tetraethylammonium [TEA], 10(-3) M; charybdotoxin, 10(-7) M; glibenclamide, 10(-6) M; 4-aminopyridine [4-AP], 10(-3) M; BaCl2, 5 x 10(-5) M; and apamin, 10(-6) M) alone failed to affect the responses to DEA/NO. However, a combination of TEA, glibenclamide, 4-AP, and BaCl2 partially blocked the relaxant effects of DEA/NO. In addition, the effects of DEA/NO were inhibited by the thromboxane A2 analog U46619 (3 x 10(-7) M).

CONCLUSIONS

Inhibitors of the large-conductance or small-conductance Ca++-activated K+ channels, the adenosine triphosphate-sensitive K+ channels, and the delayed-rectifier or inward-rectifier K+ channels failed to alter the effects of DEA/NO when only one K+ channel blocker was used. However, a regimen of a combination of K+ channel blockers that possess selectivity for different channels demonstrated that different K+ channel types are involved; these channels may function in a redundant manner and compensate for each other. Selective thromboxane A2 agonists are capable of inhibiting the relaxant response to the NO donor.

MHC-linked olfactory receptor loci exhibit polymorphism and contribute to extended HLA/OR-haplotypes

Clusters of olfactory receptor (OR) genes are found on most human chromosomes. They are one of the largest mammalian multigene families. Here, we report a systematic study of polymorphism of OR genes belonging to the largest fully sequenced OR cluster. The cluster contains 36 OR genes, of which two belong to the vomeronasal 1 (V1-OR) family. The cluster is divided into a major and a minor region at the telomeric end of the HLA complex on chromosome 6. These OR genes could be involved in MHC-related mate preferences. The polymorphism screen was carried out with 13 genes from the HLA-linked OR cluster and three genes from chromosomes 7, 17, and 19 as controls. Ten human cell lines, representing 18 different chromosome 6s, were analyzed. They were from various ethnic origins and exhibited different HLA haplotypes. All OR genes tested, including those not linked to the HLA complex, were polymorphic. These polymorphisms were dispersed along the coding region and resulted in up to seven alleles for a given OR gene. Three polymorphisms resulted either in stop codons (genes hs6M1-4P, hs6M1-17) or in a 16-bp deletion (gene hs6M1-19P), possibly leading to lack of ligand recognition by the respective receptors in the cell line donors. In total, 13 HLA-linked OR haplotypes could be defined. Therefore, allelic variation appears to be a general feature of human OR genes.

Multiple primaries in pancreatic cancer patients: indicator of a genetic predisposition?

BACKGROUND

The genetic basis of several familial cancers including breast and colon cancers has been identified recently. The occurrence of multiple cancers in one individual is also suggestive of a genetic predisposition. To evaluate inherited predisposition in pancreatic cancer we compared the clinical data of pancreatic cancer patients with and without multiple primaries as well as the frequency of malignancies among their relatives.

METHODS

Detailed data on 69 pancreatic cancer patients included survival time and TNM-classification. Index case data were separated into two groups. The first group (group 1) developed only pancreatic cancer during their lifetime, whereas the second group (group 2) developed additional primary tumours. A systematic family history was taken from 59 of these pancreatic cancer patients using a standardized questionnaire. The pancreatic cancers and the multiple primaries of the 59 patients were histologically proven.

RESULTS

Of the 69 pancreatic cancer patients, 13 (18.8%) had multiple primaries. Neither the clinical data nor the survival data of the index cases revealed differences between the two groups (all nominal P-values >0.05). In the family history study blood relatives developed a malignancy in 51% (24 of 47) of the families in group 1 compared to 75% (9 of 12) in group 2. The risk of relatives in group 2 of developing a malignant tumour was significantly higher (P = 0.034) than in group 1 after adjustments for family size and age of disease onset of the index case. The cancer spectrum of the 59 families mainly included tumours of the digestive tract and the reproductive organs.

CONCLUSIONS

A multiple primary cancer history is a common condition among pancreatic cancer patients. Relatives of these patients seem to have an increased risk for the development of distinct malignant solid tumours, which might be caused by an inherited predisposition. Clinical and genetic investigation of pancreatic cancer patients with multiple primaries and their families might lead to the identification of predisposing gene defects providing a new goal for the understanding of a shared genetic basis of different solid tumours.

Rates of psychiatric disorders in a clinical study group of adolescents with extreme obesity and in obese adolescents ascertained via a population based study

OBJECTIVE

To compare rates of DSM-IV psychiatric disorders between (1) a clinical study group of extremely obese adolescents and young adults, (2) gender-matched population-based obese controls and (3) a population-based control group of the same age range.

DESIGN

Rates of psychiatric disorders were assessed in (1) the clinical study group of obese adolescents and (2) the population based sample of obese adolescents, and compared to (3) a large population-based control group using a standardized psychiatric interview.

SUBJECTS

(1) Clinical study group: 30 female and 17 male extremely obese adolescents and young adults (age range: 15-21 y; mean BMI:42.4 kg/m2). (2) Thirty females and 17 males with the highest BMI (age range 15-21 y; mean BMI: 29.8 kg/m2) of a population-based control group encompassing 1655 (805 males) adolescents and young adults. (3) The population based control group excluding the 30 females and 17 males with the highest BMI (n = 1608; 788 males).

MEASUREMENTS

Munich-Composite International Diagnostic Interview (M-CIDI) allowing for DSM-IV diagnoses.

RESULTS

High rates of mood, anxiety, somatoform and eating disorders were detected in the clinical sample of obese adolescents which exceeded those observed in population controls (all P-values < 0.01). Rates between population-based obese adolescents and young adults and population controls did not differ. In most patients the psychiatric disorders set in after onset of obesity. 57% and 35% of the female and male patients, respectively, reported eating binges with lack of control. However, less than one-half of these patients qualified for a DSM-IV diagnosis of an eating disorder.

CONCLUSIONS

Extremely obese adolescents and young adults who seek long-term inpatient treatment have a high lifetime prevalence for affective, anxiety, somatoform and eating disorders. Because the mean BMI of the clinical study group was considerably higher than that of the obese population controls, we were not able to clarify whether the high rate of psychopathology in the study group was related to the extreme obesity or to their treatment-seeking behavior.

Polymorphisms in olfactory receptor genes: a cautionary note

The hundreds of human olfactory receptor (OR) genes are organized into clusters occurring on nearly every chromosome. Although their sequences are not always closely related, they share stretches of considerable similarity, both at the amino acid and nucleotide levels. We demonstrate here that an HLA complex-linked OR sequence, FAT11, for which recently a number of alleles have been claimed within the Hutterites, contains sequences derived from two closely related, linked OR genes, hs6M1-12 and hs6M1-16. Instead of indicating a difference between alleles of a given locus, two of the polymorphisms described for FAT11 (at amino acids 48 and 220 of the deduced protein sequence, respectively) may in fact reflect distinct sequences of hs6M1-12 and a further, closely related HLA-linked OR locus, hs6M1-13P. As a consequence, recombination rates in Hutterites in the region telomeric of HLA-G may have to be reconsidered.