Effects of apolipoprotein A-IV genotype on glucose and plasma lipoprotein levels

The effects of apolipoprotein (apo) A-IV genotype on serum glucose, total cholesterol, low density lipoprotein (LDL) cholesterol, high density lipoprotein (HDL) cholesterol, triglyceride and glucose concentrations were ascertained in a population of 373 men and 361 women with a mean age of about 57 years. Subjects were evaluated at entry into a lifestyle intervention program. Apolipoprotein A-IV genotype variations at residues 347 and 360 were examined, as these mutations affect the sequence of apo A-IV, a major protein constituent of intestinal triglyceride-rich lipoprotein and HDL. With regard to the apo A-IV 360 mutation, 16.4% of the females and 13.4% of the males carried the apo A-IV 2-allele, almost entirely in the heterozygous state. No effect of the apo A-IV 1/2 genotype was observed in either men or women on total cholesterol, LDL cholesterol, HDL cholesterol, triglyceride, the total cholesterol (TC)/HDL ratio, or on A-I, A-IV and apo B levels. This was also the case for the apo A-IV 347 mutation. However, women with the apo A-IV 360 1/2 genotype had significantly (p < 0.005) higher glucose levels (105.5 mg/dl) compared with the 1/1 wild-type (94.0 mg/dl). All analyses were also adjusted for age, body mass index, medications, alcohol use and cigarette smoking. The prevalence of the 347 mutation was somewhat higher than the 360 mutation, with 29% of the females and 32.0% of the males being heterozygous for this mutation, and 3.9% of the females and 5.4% of the males being homozygous for this mutation. These data are consistent with the concept that the apo A-IV 360 and 347 genotypes have no significant effect on apo A-IV levels and other lipid parameters in either gender. However, apo A-IV 360 1/2 genotype did have a significant effect on serum glucose levels in women.     

Mutation spectrum and genotype-phenotype analyses in Cowden disease and Bannayan-Zonana syndrome, two hamartoma syndromes with germline PTEN mutation

The tumour suppressor gene PTEN , which maps to 10q23.3 and encodes a 403 amino acid dual specificity phosphatase (protein tyrosine phosphatase; PTPase), was shown recently to play a broad role in human malignancy. Somatic PTEN deletions and mutations were observed in sporadic breast, brain, prostate and kidney cancer cell lines and in several primary tumours such as endometrial carcinomas, malignant melanoma and thyroid tumours. In addition, PTEN was identified as the susceptibility gene for two hamartoma syndromes: Cowden disease (CD; MIM 158350) and Bannayan-Zonana (BZS) or Ruvalcaba-Riley-Smith syndrome (MIM 153480). Constitutive DNA from 37 CD families and seven BZS families was screened for germline PTEN mutations. PTEN mutations were identified in 30 of 37 (81%) CD families, including missense and nonsense point mutations, deletions, insertions, a deletion/insertion and splice site mutations. These mutations were scattered over the entire length of PTEN , with the exception of the first, fourth and last exons. A 'hot spot' for PTEN mutation in CD was identified in exon 5 that contains the PTPase core motif, with 13 of 30 (43%) CD mutations identified in this exon. Seven of 30 (23%) were within the core motif, the majority (five of seven) of which were missense mutations, possibly pointing to the functional significance of this region. Germline PTEN mutations were identified in four of seven (57%) BZS families studied. Interestingly, none of these mutations was observed in the PTPase core motif. It is also worthy of note that a single nonsense point mutation, R233X, was observed in the germline DNA from two unrelated CD families and one BZS family. Genotype-phenotype studies were not performed on this small group of BZS families. However, genotype-phenotype analysis inthe group of CD families revealed two possible associations worthy of follow-up in independent analyses. The first was an association noted in the group of CD families with breast disease. A correlation was observed between the presence/absence of a PTEN mutation and the type of breast involvement (unaffected versus benign versus malignant). Specifically and more directly, an association was also observed between the presence of a PTEN mutation and malignant breast disease. Secondly, there appeared to be an interdependent association between mutations upstream and within the PTPase core motif, the core motif containing the majority of missense mutations, and the involvement of all major organ systems (central nervous system, thyroid, breast, skin and gastrointestinal tract). However, these observations would need to be confirmed by studying a larger number of CD families.      

Mouse homologues of the human AZF candidate gene RBM are expressed in spermatogonia and spermatids, and map to a Y chromosome deletion interval associated with a high incidence of sperm abnormalities

An RNA-binding motif (RBM) gene family has been identified on the human Y chromosome that maps to the same deletion interval as the 'azoospermia factor' (AZF). We have identified the homologous gene family (Rbm) on the mouse Y with a view to investigating the proposal that this gene family plays a role in spermatogenesis. At least 25 and probably >50 copies of Rbm are present on the mouse Y chromosome short arm located between Sry and the centromere. As in the human, a role in spermatogenesis is indicated by a germ cell-specific pattern of expression in the testis, but there are distinct differences in the pattern of expression between the two species. Mice carrying the deletion Yd1, that maps to the proximal Y short arm, are female due to a position effect resulting in non-expression of Sry ; sex-reversing such mice with an Sry transgene produces males with a high incidence of abnormal sperm, making this the third deletion interval on the mouse Y that affects some aspect of spermatogenesis. Most of the copies of Rbm map to this deletion interval, and the Yd1males have markedly reduced Rbm expression, suggesting that RBM deficiency may be responsible for, or contribute to, the abnormal sperm development. In man, deletion of the functional copies of RBM is associated with meiotic arrest rather than sperm anomalies; however, the different effects of deletion are consistent with the differences in expression between the two species.      

ATRX encodes a novel member of the SNF2 family of proteins: mutations point to a common mechanism underlying the ATR-X syndrome

It was shown recently that mutations of the ATRX gene give rise to a severe, X-linked form of syndromal mental retardation associated with alpha thalassaemia (ATR-X syndrome). In this study, we have characterised the full-length cDNA and predicted structure of the ATRX protein. Comparative analysis shows that it is an entirely new member of the SNF2 subgroup of a superfamily of proteins with similar ATPase and helicase domains. ATRX probably acts as a regulator of gene expression. Definition of its genomic structure enabled us to identify four novel splicing defects by screening 52 affected individuals. Correlation between these and previously identified mutations with variations in the ATR-X phenotype provides insights into the pathophysiology of this disease and the normal role of the ATRX protein in vivo.      

Matrix metalloproteinases (MMP), EMMPRIN (extracellular matrix metalloproteinase inducer) and mitogen-activated protein kinases (MAPK): Co-expression in metastatic serous ovarian carcinoma

Activation or suppression of intracellular signaling via the mitogen-activated protein kinase (MAPK) family has been linked to expression of matrix metalloproteinases (MMP) in experimental models, but this association has not been demonstrated in clinical material. The objective of this study was to investigate the possible association between expression and activity of MMP, expression of the MMP inducer EMMPRIN, and the expression (level) and phosphorylation status (activity) of the extracellular-regulated kinase (ERK), c-Jun amino-terminal kinase (JNK) and high osmolarity glycerol response kinase (p38) in effusions from patients diagnosed with serous ovarian carcinoma. MAPK level and activity were studied in 55 effusions using immunoblotting. MMP-1, MMP-2, MMP-9 and EMMPRIN expression was studied using immunocytochemistry (ICC) and mRNA in situ hybridization (ISH). The gelatinolytic activity of MMP-2 and MMP-9 was measured by zymography. ERK and phospho-ERK (p-ERK) were detected in 54/55 (98%) and 50/55 (91%) specimens, respectively. JNK and p-JNK were detected in 53/55 (96%) and 38/55 (69%) specimens, respectively. p38 was expressed in 54/55 (98%) specimens, and its phosphorylated form was found in 51/55 (92%). MMP-2 mRNA expression (P=0.048), protein expression (P=0.046) and gelatinolytic activity (P=0.039) correlated with ERK phosphorylative activity. MMP-2 activity also correlated with p38 activity (P=0.017). MMP-9 protein expression correlated with phosphorylation of p38 (P=0.046), but enzyme activity showed inverse relationship with both p-ERK (P=0.05) and p-p38 (P=0.033) expression. EMMPRIN expression correlated with MMP-1 (P<0.001), MMP-2 (P=0.042) and MMP-9 (P=0.029) expression, as well as with ERK activity (P=0.001). Our results present the first evidence of a possible link between MAPK signaling and MMP expression and activity in vivo. These data may expand our understanding regarding the mechanisms by which MMP synthesis is regulated in effusions and possibly affect treatment strategies for this form of malignancy. This revised version was published online in July 2006 with corrections to the Cover Date.     

Toll-like receptor 9 contributes to recognition of Mycobacterium bovis Bacillus Calmette-Guérin by Flt3-ligand generated dendritic cells

Recognition of mycobacteria by the innate immune system is essential for the development of an adaptive immune response. Mycobacterial antigens stimulate antigen presenting cells (APCs) through distinct Toll-like receptors (TLRs) resulting in rapid activation of the innate immune system. The role of TLRs during infection with Mycobacterium bovis Bacillus Calmette-Guérin (BCG) has been evaluated for TLR2 and TLR4 only. Surprisingly, despite the fact that immune stimulatory CpG-motifs have been originally derived from BCG, for the vaccine strain the role of TLR9 has not been addressed before. To identify the set of TLRs involved in the recognition of BCG, we infected bone marrow-derived macrophages and bone marrow-derived dendritic cells (Flt3-ligand generated DCs) from TLR2, TLR3, TLR4, TLR7, TLR9, MyD88 knockout, TLR2/4 and TLR2/4/9 multiple knockout mice. The degree of activation and stimulation was determined by TNFα, IL-6 and IL-12p40 ELISA. Activation of DCs was measured by surface expression of the costimulatory molecule CD86. We observed the most dramatic reduction of the inflammatory response for TLR2-deficient antigen presenting cells. Both macrophages and DCs produce markedly decreased amounts of TNFα and IL-6 in the absence of TLR2 whereas no significant reduction could be observed for TLR3, 4, 7, 9 single TLR-knockouts. However, IL-12 production in DCs appears not exclusively dependent on TLR2 and only in TLR2/4/9-deficient DCs BCG-induced IL-12 is reduced to background levels. Similarly, up-regulation of CD86 is abolished only in TLR2/4/9-deficient DCs supporting a role of TLR9 in the recognition of M. bovis BCG by murine dendritic cells.     

Evaluation of microparticle enzyme immunoassays for immunoglobulins G and M to rubella virus and Toxoplasma gondii on the Abbott IMx automated analyzer.

The ability of the Abbott IMx automated analyzer to detect immunoglobulin G (IgG) and IgM antibodies to rubella virus and to Toxoplasma gondii was compared with the abilities of RUBAZYME, RUBAZYME-M, ABBOTT TOXO-G enzyme immunoassay, and ABBOTT TOXO-M enzyme immunoassay, respectively. Specimens that produced discordant results were evaluated by RUBACELL II, Behring Enzygnost-Rubella enzyme-linked immunosorbent assay, Behring Enzygnost Toxoplasmosis/IgG, and bioMerieux Toxo-ISAGA (immunosorbent agglutination assay), respectively. After resolution of discordant results, IMx Rubella IgG, IMx Rubella IgM, IMx Toxo IgG, and IMx Toxo IgM antibody assays had sensitivities of 99.9, 100, 98.0, and 100%; specificities of 98.9, 99.0, 97.5, and 98.7%; and accuracies of 99.8, 99.3, 97.8, and 98.8%, respectively.     

Homo- and heteromeric assembly of TRP channel subunits

Mammalian homologues of the Drosophila melanogaster transient receptor potential (TRP) channels are the second largest cation channel family within the superfamily of hexahelical cation channels. Most mammalian TRP channels function as homooligomers and mediate mono- or divalent cation entry upon activation by a variety of stimuli. Because native TRP channels may be multimeric proteins of possibly complex composition, it is difficult to compare cation conductances in native tissues to those of clearly defined homomeric TRP channel complexes in living cells. Therefore, the possibility of heteromeric TRP channel assembly has been investigated in recent years by several groups. As a major conclusion of these studies, most heteromeric TRP channel complexes appear to consist of subunit combinations only within relatively narrow confines of phylogenetic subfamilies. Although the general capability of heteromer formation between closely related TRP channel subunits is now clearly established, we are only beginning to understand whether these heteromeric complexes are of physiological significance. This review summarizes the current knowledge on the promiscuity and specificity of the assembly of channel complexes composed of TRPC-, TRPV- and TRPM-subunits of mammalian TRP channels.     

Über zwei neue Fälle von hereditärer nichtsphärocytärer hämolytischer Anämie bei Glucose-6-Phosphat-Dehydrogenase-Defekt in einer norddeutschen Familie

Zusammenfassung Bei zwei Geschwistern norddeutscher Abstammung findet sich das Krankheitsbild einer hereditären nichtsphärocytären hämolytischen Anämie, dem ein Defekt der Glucose-6-Phosphatdehydrogenase der Erythrocyten zugrundeliegt. Das Protein weist von der Norm abweichende qualitative Eigenschaften auf. Die histochemisch belegbare Heterozygotie der Mutter für die anomale genetische Information wird bei biochemischer Untersuchung der Gesamtpopulation der Erythrocyten durch den relativ hohen Anteil der normalen Erythrocyten überdeckt. Das klinische Bild des einen der beiden Geschwister ist durch ein zusätzliches kongenitales Vitium cordis (Vorhofseptumdefekt vom Ostium secundum-Typ) kompliziert.

---

Summary Two brothers of a family in North-Germany have a hereditary non spherocytic hemolytic anemia with glucose-6-phosphate dehydrogenase deficiency in erythrocytes. The activity of the enzyme was 20% resp. 10% of that found in normal red cells. In the patients the enzyme protein were showing not only a quantitative difference from normal activity, but also a qualitative abnormality of the protein. In the parents the behaviour of the enzyme protein is normal. The total enzyme level of the mother's red cells is in the normal range, but histochemically the heterozygosity (ie146-1) were found. One of the patients were splenectomized without response. In the other patient a congenital heart disease (ostium secundum defect) is associated with the anemia.

     

Änderungen der Herzdynamik durch arterielle Gegenpulsation

Zusammenfassung Bei nicht exakt erfolgender diastolischer arterieller Gegenpulsation kommt es nicht allein zu dem erwünschten Absinken des herzeigenen systolischen Druckes sowie des Spannungszeitindexes. Zusätzlich werden Anteile der Systole durch den Druckvolumenstoß miterfaßt. Die resultierenden Druckänderungen vor allem des LV konnten in drei Abschnitte gegliedert werden.I. Trifft der absteigende Anteil des Gegenimpulses auf das Ende der isometrischen Phase bzw. den Beginn der Austreibungsperiode des linken Ventrikels, so wird der enddiastolische Aortendruck erhöht, die Aortenklappen öffnen sich verspätet, der LV-Druck liegt bei unverändertem LVEDD höher als beim Kontrollschlag, ohne daß immer eine Minderung des Schlagvolumens eintritt. Dieser anscheinende Widerspruch zu den Frank-Starlingschen Gesetzen konnte in der vorliegenden Untersuchungsanordnung nicht eindeutig geklärt werden, weil das normale systolische Durchflußvolumen mit der aufgezwungenen Volumenänderung interferiert und dadurch ein zu hohes Schlagvolumen vorgetäuscht werden kann.II. Fällt der Druckvolumenstoß zeitlich mit dem Maximum der ventrikulären Druckentwicklung zusammen, so nimmt nach den Frank-Starlingschen Gesetzen das Schlagvolumen bei vermehrter ventrikulärer Druckentwicklung ab.III. Erfaßt der Beginn des Gegenimpulses das Ende der ventrikulären Austreibungsphase, so resultiert eine zusätzliche isometrische Kontraktion, die sich der Form des Gegenimpulses angleicht. Die Aortenklappen schließen vorzeitig, und die Austreibungsphase wird verkürzt.Mit 5 TextabbildungenMit Unterstützung der Deutschen Forschungsgemeinschaft.