Mutations in the tight-junction gene claudin 19 (CLDN19) are associated with renal magnesium wasting, renal failure, and severe ocular involvement

Claudins are major components of tight junctions and contribute to the epithelial-barrier function by restricting free diffusion of solutes through the paracellular pathway. We have mapped a new locus for recessive renal magnesium loss on chromosome 1p34.2 and have identified mutations in CLDN19, a member of the claudin multigene family, in patients affected by hypomagnesemia, renal failure, and severe ocular abnormalities. CLDN19 encodes the tight-junction protein claudin-19, and we demonstrate high expression of CLDN19 in renal tubules and the retina. The identified mutations interfere severely with either cell-membrane trafficking or the assembly of the claudin-19 protein. The identification of CLDN19 mutations in patients with chronic renal failure and severe visual impairment supports the fundamental role of claudin-19 for normal renal tubular function and undisturbed organization and development of the retina.

Oxytocin release and lactation performance in Syrian Shami cattle milked with and without suckling

Oxytocin (OT) release and lactation performance in primiparous Syrian Shami cows were evaluated in response to two different machine milking regimes. Six cows were milked in the presence of the calves (PC) and subsequently suckled, whereas six cows were exclusively machine milked without the presence of their calves (WC) until day 91 post partum. Milk yield and milk constituents were determined weekly. The degree of udder evacuation was determined by the succeeding removal of residual milk. PC released OT during the milking process, whereas in WC no OT release was detected throughout the milking process. Consequently, the residual milk fraction was much lower in PC than in WC (11% v. 58%, P<0.05) and daily milk yield until day 91 post partum was higher in PC than in WC (12.6+/-0.3 v. 7.1+/-0.4 kg, P<0.05). In conclusion, Syrian Shami cattle are not suitable to be exclusively machine milked without the presence of their calves.

Disseminated Mycobacterium marinum infection with extensive cutaneous eruption and bacteremia in an immunocompromised patient

Mycobacterium marinum can cause fish tank granuloma (or swimming pool or aquarium granuloma) in immunocompetent patients. Dissemination of Mycobacterium marinum-infection is a rare condition which occurs mainly in immunocompromised patients and can be life-threatening. We report the case of an 87-year-old woman who was treated with oral corticosteroids for polymyalgia rheumatica for many years and developed erythema nodosum-like lesions on the right forearm and arthritis of the right wrist. By increasing the steroid dosage and adding methotrexate only short-term remission was achieved. Seven months later painful erythematous nodules occurred on all extremities which became necrotic, ulcerative and suppurative. Ziehl-Neelsen staining revealed acid-fast bacilli and Mycobacterium marinum was cultured from skin biopsies, blood, and urine. The critically ill patient was treated with clarithromycin and ethambutol resulting in a dramatic improvement of the general condition. After four months, doxycycline had to be added because of new skin lesions. This case illustrates the impact of Mycobacterium marinum infection in immunocompromised patients.

[Pulmonary microscopic tumor embolism syndrome]

HISTORY: A 76-year-old woman and a 62-year-old man were both referred to our clinic because of an unexplained weight loss, increasing dry cough and shortness of breath. INVESTIGATIONS: Investigations revealed an adenocarcinoma of the colon with retroperitoneal, mediastinal and supraclavicular lymph node metastasis and poorly differentiated carcinoma of the prostate with extensive bone metastases. During their hospital stay both patients developed increasing shortness of breath and clinical signs of right heart failure. Echocardiography confirmed severe pulmonary hypertension and dilatation of the right ventricle in both patients. Despite the high degree of clinical suspicion CT scans of the thorax could not demonstrate pulmonary embolism. DIAGNOSIS, TREATMENT AND COURSE: During the following days the patients condition deteriorated further and both patients' died from irreversible right heart failure. Both autopsies showed extensive metastatic adenocarcinoma with marked angiosis carcinomatosa of the lungs with numerous occlusions of small arteries and arterioles and resulting cor pulmonale. Thrombotic pulmonary embolism could not be detected. CONCLUSION: In patients with malignant neoplasms, especially adenocarcinomas, dyspnea and signs of increasing pulmonary artery pressure, the possibility of a microscopic pulmonary tumor embolism should be considered after exclusion of more usual causes especially thrombotic pulmonary embolism. In selected cases a cytologic examination of blood aspirated from a wedged pulmonary artery catheter can be performed to prove angiosis is carcinomatosa.

A degradation-sensitive anionic trypsinogen (PRSS2) variant protects against chronic pancreatitis

Chronic pancreatitis is a common inflammatory disease of the pancreas. Mutations in the genes encoding cationic trypsinogen (PRSS1) and the pancreatic secretory trypsin inhibitor (SPINK1) are associated with chronic pancreatitis. Because increased proteolytic activity owing to mutated PRSS1 enhances the risk for chronic pancreatitis, mutations in the gene encoding anionic trypsinogen (PRSS2) may also predispose to disease. Here we analyzed PRSS2 in individuals with chronic pancreatitis and controls and found, to our surprise, that a variant of codon 191 (G191R) is overrepresented in control subjects: G191R was present in 220/6,459 (3.4%) controls but in only 32/2,466 (1.3%) affected individuals (odds ratio 0.37; P = 1.1 x 10(-8)). Upon activation by enterokinase or trypsin, purified recombinant G191R protein showed a complete loss of trypsin activity owing to the introduction of a new tryptic cleavage site that renders the enzyme hypersensitive to autocatalytic proteolysis. In conclusion, the G191R variant of PRSS2 mitigates intrapancreatic trypsin activity and thereby protects against chronic pancreatitis.

Keratin 8 sequence variants in patients with pancreatitis and pancreatic cancer

Keratin 8 (KRT8) is one of the major intermediate filament proteins expressed in single-layered epithelia of the gastrointestinal tract. Transgenic mice over-expressing human KRT8 display pancreatic mononuclear infiltration, interstitial fibrosis and dysplasia of acinar cells resulting in exocrine pancreatic insufficiency. These experimental data are in accordance with a recent report describing an association between KRT8 variations and chronic pancreatitis. This prompted us to investigate KRT8 polymorphisms in patients with pancreatic disorders. The KRT8 Y54H and G62C polymorphisms were assessed in a cohort of patients with acute and chronic pancreatitis of various aetiologies or pancreatic cancer originating from Austria (n=16), the Czech Republic (n=90), Germany (n=1698), Great Britain (n=36), India (n=60), Italy (n=143), the Netherlands (n=128), Romania (n=3), Spain (n=133), and Switzerland (n=129). We also studied 4,234 control subjects from these countries and 1,492 control subjects originating from Benin, Cameroon, Ethiopia, Ecuador, and Turkey. Polymorphisms were analysed by melting curve analysis with fluorescence resonance energy transfer probes. The frequency of G62C did not differ between patients with acute or chronic pancreatitis, pancreatic adenocarcinoma and control individuals. The frequency of G62C varied in European populations from 0.4 to 3.8%, showing a northwest to southeast decline. The Y54H alteration was not detected in any of the 2,436 patients. Only 3/4,580 (0.07%) European, Turkish and Indian control subjects were heterozygous for Y54H in contrast to 34/951 (3.6%) control subjects of African descent. Our data suggest that the KRT8 alterations, Y54H and G62C, do not predispose patients to the development of pancreatitis or pancreatic cancer.

Slow fertilization of stickleback eggs: the result of sexual conflict?

BACKGROUND: The fertilization success in sperm competition in externally fertilizing fish depends on number and quality of sperm. The time delay between sequential ejaculations may further influence the outcome of sperm competition. Such a time interval can load the raffle over fertilization if fertilization takes place very fast. Short fertilization times are generally assumed for externally fertilizing fish such as the three-spined stickleback (Gasterosteus aculeatus). In this pair-spawning fish, territorial males often try to steal fertilizations in nests of neighbouring males. This sneaking behaviour causes sperm competition. Sneakers will only get a share of paternity when eggs are not fertilized immediately after sperm release. Contrary to males, females may be interested in multiple paternity of their clutch of eggs. There thus may be a sexual conflict over the speed of fertilization. RESULTS: In this study we used two different in vitro fertilization experiments to assess how fast eggs are fertilized in sticklebacks. We show that complete fertilization takes more than 5 min which is atypically long for externally fertilizing fishes. CONCLUSION: This result suggests that the time difference does not imply high costs to the second stickleback male to ejaculate. Slow fertilization (and concomitant prolonged longevity of sperm) may be the result of sexual conflict in which females aimed at complete fertilization and/or multiple paternity.

Role of the NFKB1 -94ins/delATTG promoter polymorphism in IBD and potential interactions with polymorphisms in the CARD15/NOD2, IKBL, and IL-1RN genes

BACKGROUND: Recently, an association of the NFKB1 polymorphism -94ins/delATTG with ulcerative colitis (UC) has been reported. This 4-bp insertion/deletion polymorphism is localized in the promoter region of the NFKB1 gene and appears to be functionally relevant. The aim of the present study was to confirm the association of the -94ins/delATTG (W/D) NFKB1 promoter polymorphism with UC in a population of German origin and to test for a potential association with Crohn's disease (CD). Furthermore, potential interactions of the -94ins/delATTG polymorphism with the IKBL and the IL-1RN genes should be determined. MATERIALS AND METHODS: The study population comprised 630 patients with CD, 365 patients with UC, and 974 healthy controls. Genotyping was performed using polymerase chain reaction and restriction fragment length polymorphism analysis. For statistical evaluation, the chi-square test and the Fisher exact test were used. RESULTS: No significant association of the W/D NFKB1 polymorphism with CD or UC was detected. In addition, no significant interactions between the -94ins/delATTG NFKB1 polymorphism and polymorphisms within the IKBL and the IL-1RN genes, respectively, were found in CD or UC. Also, no significant interactions of the NFKB1 polymorphism with mutations of the CARD15/NOD2 gene and with clinical phenotypes were detected in CD. Moreover, no associations of the NFKB1 polymorphism were found in UC depending on disease localization. CONCLUSIONS: The present study could not confirm the reported association of the -94ins/delATTG NFKB1 polymorphism with UC and also found no evidence for a role of this polymorphism in CD. The results do not give evidence for a role of this NFKB1 polymorphism in the pathogenesis of UC and CD.

Angiopoietin-1 and angiopoietin-2 share the same binding domains in the Tie-2 receptor involving the first Ig-like loop and the epidermal growth factor-like repeats

Angiopoietin-1 (Ang-1) and angiopoietin-2 (Ang-2) have been identified as ligands with different effector functions of the vascular assembly and maturation-mediating receptor tyrosine kinase Tie-2. To understand the molecular interactions of the angiopoietins with their receptor, we have studied the binding of Ang-1 and Ang-2 to the Tie-2 receptor. Enzyme-linked immunosorbent assay-based competition assays and co-immunoprecipitation experiments analyzing the binding of Ang-1 and Ang-2 to truncation mutants of the extracellular domain of Tie-2 showed that the first Ig-like loop of Tie-2 in combination with the epidermal growth factor (EGF)-like repeats (amino acids 1-360) is required for angiopoietin binding. The first Ig-like domain or the EGF-like repeats alone are not capable of binding Ang-1 and Ang-2. Concomitantly, we made the surprising finding that Tie-2 exon-2 knockout mice do express a mutated Tie-2 protein that lacks 104 amino acids of the first Ig-like domain. This mutant Tie-2 receptor is functionally inactive as shown by the lack of ligand binding and receptor phosphorylation. Collectively, the data show that the first 104 amino acids of the Tie-2 receptor are essential but not sufficient for angiopoietin binding. Conversely, the first 360 amino acids (Ig-like domain plus EGF-like repeats) of the Tie-2 receptor are necessary and sufficient to bind both Ang-1 and Ang-2, which suggests that differential receptor binding is not likely to be responsible for the different functions of Ang-1 and Ang-2.