Trimethylamine-N-oxide is elevated in the acute phase after ischaemic stroke and decreases within the first days.

BACKGROUND AND PURPOSE: Trimethylamine-N-oxide (TMAO) is a biomarker of the gut microbiome and correlates with the risk of cardiovascular diseases. However, conflicting data exist on the specific role of TMAO in ischaemic stroke patients. We aimed to analyze the time course of TMAO levels in stroke patients compared with controls. METHODS: In this prospective, case-control study, patients suffering from ischaemic stroke (onset <24 h) and control patients with less than two cardiovascular risk factors were enrolled. Plasma TMAO levels were analyzed on admission, after 48 h and after 3 months. The primary endpoint was the difference in TMAO levels on admission between stroke patients and controls. RESULTS: A total of 196 patients with ischaemic stroke and 100 controls were included between February 2018 and April 2019. Plasma TMAO levels on admission were significantly higher in stroke patients than in controls [median value 4.09 (2.87-6.49) vs. 3.16 (2.08-5.16) µmol/L, P = 0.001]. There was a significant decrease in TMAO levels in stroke patients after 48 h [median at 48 h, 3.49 (2.30-5.39) µmol/L, P = 0.027]. TMAO levels increased again 3 months after stroke [median 4.23 (2.92-8.13) µmol/L, P = 0.047]. In controls, TMAO levels did not change between admission and after 48 h [median at 48 h, 3.14 (1.63-4.61) µmol/L, P = 0.11]. An inverse correlation between TMAO values and kidney function was found (Spearman rho -0.334, P < 0.001). CONCLUSIONS: Our study emphasizes the importance of the time course of TMAO levels after ischaemic stroke. Future studies should define the time point of TMAO analysis, preferably in the acute phase (<24 h).

Long-term ovarian function in women treated with CHOP or CHOP plus etoposide for aggressive lymphoma.

BACKGROUND: Chemotherapy-associated ovarian damage comprises not only infertility, but also premature menopause. The latter has been reported as a consequence of alkylating chemotherapy for breast cancer or Hodgkin's lymphoma. In this study, we assessed the long-term impact of CHOP (cyclophosphamide, doxorubicin, vincristine, and prednisone)-like regimens on ovarian function in patients with aggressive non-Hodgkin lymphoma (NHL). PATIENTS AND METHODS: Long-term survivors after CHOP or CHOP plus etoposide (CHOEP) treatment within the Mabthera International Trial or the NHL-B1 trial of the German NHL Study Group were requested to respond to a questionnaire and to consent to blood sampling for hormone assessment. RESULTS: A total of 46 of 81 contacted patients with a median age of 32.5 years at the time of enrolment into the aforementioned clinical trials responded to the questionnaire. The median follow-up after completion of treatment was 14 years. Last menstrual bleeding occurred significantly earlier in patients compared with the general population (47 versus 51 years, P < 0.0001). In comparison to the distribution of menopausal symptoms in the general population, the percentage of women with moderate or severe menopausal symptoms was increased. In 23 patients who agreed to participate in laboratory analyses, anti-Muller hormone as a marker of ovarian reserve was decreased when compared with correspondent age groups of the general population. CONCLUSION: Although most female patients regain fertility after CHOP-like chemotherapy, late ovarian impairment occurs frequently. Therefore, awareness of such delayed side-effects at the time of counselling is of importance.

Prevalence of renal dysfunction in ischaemic stroke and transient ischaemic attack patients with or without atrial fibrillation.

BACKGROUND AND PURPOSE: Chronic kidney disease (CKD) is associated with a higher risk of stroke and atrial fibrillation (AF). There are limited data on the comorbidity of renal dysfunction and AF in stroke patients. Our aim was to determine the frequency of kidney dysfunction in ischaemic stroke patients with and without AF. METHODS: In a prospectively collected, single center cohort of acute ischaemic stroke and transient ischaemic attack (TIA) patients, glomerular filtration rate (eGFR) was estimated using the Modification of Diet in Renal Disease equation on admission. Renal function was graded into five categories (cat.): cat. 1, eGRF ≥90 ml/min/1.73 m(2); cat. 2, 60-89; cat. 3, 30-59; cat. 4, 15-29; cat. 5, <15. The diagnosis of AF was based on medical history, a 12-lead electrocardiogram (ECG) and 24-h Holter or continuous ECG monitoring. RESULTS: In total, 2274 patients (1727 stroke, 547 TIA; median age 71.0) were included. Median eGFR was 78.6 ml/min/1.73 m(2) (interquartile range 61/95); 21.1% were in cat. 3, 2.1% in cat. 4, 0.7% in cat. 5. In all, 535 patients (23.5%) suffered from AF; 28.0% of these were in cat. 3, 2.6% and 0.8% in cat. 4 and cat. 5, respectively. In multivariable analysis, age [odds ratio (OR) 1.1], diabetes (OR 1.8), heart failure (OR 1.7) and AF (OR 1.4) were independently associated with kidney dysfunction (eGFR < 60). CONCLUSIONS: Renal dysfunction is far more common in stroke patients than in the general population and more common in AF-related stroke. These findings may have implications for the choice of anticoagulants.

A novel missense mutation T101N in the melanocortin-4 receptor gene associated with obesity.

Mutations in the melanocortin-4 receptor (MC4R) are associated with severe obesity, independent of their effect on cortisol or thyroid-stimulating hormone levels. We examined a morbidly obese male (BMI = 62 kg/m²) with a binge-eating disorder and eight family members for mutations in the MC4R gene and potential differences in leptin levels. Fifty healthy individuals served as controls. Sequence analysis revealed a novel heterozygous missense mutation (c.302 C>A, p.T101N) located in the second transmembrane domain of the receptor, which was not detected in controls. The Fisher exact test revealed an association between the T101N mutation and history of obesity (P < 0.05) in the family. The Kruskal-Wallis test showed an association between the mutation and the leptin/BMI ratio (P < 0.05), while there was no association between the T101N mutation and diabetes or arterial hypertension in the family. Although the available family was small, we could show a significant association between the heterozygous T101N mutation and obesity.

[Malignant bowel obstruction]. / Maligne intestinale Obstruktion.

Malignant bowel obstruction (MBO) is a frequent complication in patients with a progressive malignant disorder and represents a major interdisciplinary challenge in palliative care. Gastroenterology plays a pivotal role in the management of MBO. After appropriate diagnostic work-up, it is important to define treatment goals with the patient and his/her relatives, which should focus on symptom relief. Therapeutically, surgical, endoscopic and medical options are available. These will be introduced based on case reports. In the international literature MBO is being more and more considered as a distinct entity. The aim of the present review is to communicate MBO as such in the German medical literature.

Immunocytochemical localization of a large intrinsic membrane protein to the incisures and margins of frog rod outer segment disks.

Immunocytochemical techniques have localized a large protein which is an intrinsic membrane component of isolated frog rod outer segments (ROS). This large protein whose apparent mol wt is 290,000 daltons comprises about 1--3% of the ROS membrane mass. Its molar ratio to opsin is between 1:300 and 1:900. Adequate immune responses were obtained with less than 30 microgram (100 pmol) of antigen per rabbit. Antibodies to the large protein were used for its localization on thin sections of frog retina embedded in glutaraldehyde cross-linked bovine serum albumin (BSA). Specifically bound antibodies were detected by an indirect sequence with ferritin-conjugated antibodies. This technique detected the protein which is represented by 1,000--3,000 molecules per disk. This indicates that the procedure is sufficiently sensitive for analysis of membrane components in low molar proportions. The large protein was specifically localized to the incisures of ROS disks which divide the disks into lobes and to the disk margin. Thus, opsin is mobile within the membrane of the disk while the large protein is apparently constrained to the disk edges. This finding raises the possibility that special functions are also localized ot his unusual region of high curvature, and that collisions of bleached opsin with these edges are physiologically important in couter segment function.

Immunocytochemical localization of opsin in outer segments and Golgi zones of frog photoreceptor cells. An electron microscope analysis of cross-linked albumin-embedded retinas.

Adult vertebrate retinal cells (rod and cones) continuously synthesize membrane proteins and transport them to the organelle specialized for photon capture, the outer segment. The cell structures involved in the synthesis of opsin have been identified by means of immunocytochemistry at the electron microscope level. Two indirect detection systems were used: (a) rabbit antibodies to frog opsin were localized with ferritin conjugated F(ab')2 of sheep antibodies to rabbit F(ab')2 and (b) sheep antibodies to cattle opsin were coupled to biotin and visualized by means of avidin-ferritin conjugates (AvF). The reagents were applied directly to the surface of thin sections of frog retinal tissues embedded in glutaraldehyde cross-linked bovine serum albumin (BSA). Specific binding of anti-opsin antibodies indicates that opsin is localized in the disks of rod outer segments (ROS), as expected, and in the Golgi zone of the rod cell inner segments. In addition, we observed quantitatively different labeling patterns of outer segments of rods and cones with each of the sera employed. These reactions may indicate immunological homology of rod and cone photopigments. Because these quantitiative variations of labeling density extend along the entire length of the outer segment, they also serve to identify the cell which has shed its disks into adjacent pigment ipithelial cell phagosomes.

Aryl hydrocarbon receptor interacting protein gene (AIP) mutations are rare in patients with hormone secreting or non-secreting pituitary adenomas.

OBJECTIVE: Recent data suggest that mutations in the aryl hydrocarbon receptor interacting protein gene (AIP) are associated with pituitary adenomas. AIP is considered to be a tumour suppressor gene. METHODS: 110 Caucasian patients living in Germany with pituitary adenoma (55 hormone secreting, 55 non-functioning) were examined for AIP mutations. RESULTS: Three patients (2.7%) harboured an AIP germline mutation. A heterozygous mutation, R16H (c.47G>A), was found in two patients and a heterozygous G>C change in the 3'UTR, 60 bp downstream of the termination codon, in one patient. All three patients suffered from non-functioning adenoma. Additionally, a silent polymorphism, D172D (c.516C>T), was found in 3 patients with non-functioning adenoma, in 2 patients with prolactinoma and in one patient with acromegaly. CONCLUSIONS: AIP mutations are rare in sporadic pituitary adenomas in the German population and occur independently from a hormone secretion of the adenoma.

The DG10S478 variant in the TCF7L2 gene is not associated with microvascular complications in type 2 diabetes.

OBJECTIVE: The DG10S478 variant in the transcription factor 7-like 2 (TCF7L2) gene is a tetranucleotide repeat with six alleles. Alleles 0, 8 and 12 were found to account for 98% of chromosomes in population based controls. The composite allele X (non zero) has been associated with type 2 diabetes while allele 0 (no insertion) was described as protective. However, no data exist about the influence of DG10S478 variants on manifestation of diabetes and development of diabetic complications. METHODS: 250 patients with type 2 diabetes were tested for the DG10S478 allele X and its association with diabetic complications, age at diagnosis of diabetes and BMI. RESULTS: Allele 0 was found in 42.4% of the examined patients, 45.2% of the participants were found to be heterozygous and 12.4% homozygous for the composite allele X. The correlation of allele X with the age at diagnosis of diabetes was not significant. There was also no association of allele X with retinopathy, nephropathy or neuropathy. Only the correlation with BMI was statistically significant. CONCLUSIONS: The DG10S478 variant seems to have no influence on manifestation of diabetes and the development of microvascular complications.

Autoantibodies in diabetes mellitus: current utility and perspectives.

Testing of autoantibodies in individuals at risk of developing or being newly diagnosed with diabetes mellitus is currently of very limited clinical value. However, clinical studies evaluating new therapeutic options for the delay or treatment of type 1 diabetes mellitus require sensitive, specific, and reliable assays for autoimmune antibodies associated with diabetes mellitus. With immune modulatory treatment of pre-diabetes mellitus on the horizon the need of reliable assays is evident. In addition, determination of autoimmune antibodies in diabetes mellitus facilitates studies investigating the pathophysiology underlying this disease. Clinicians and researchers should be aware of the tests available, their limitations, their clinical relevance, and their indications. This review focuses on the current knowledge about antibody assays for diabetes associated autoimmunity, their clinical value, their role in diagnosing and predicting autoimmune associated diabetes mellitus, and research applications.

Computational analysis of candidate intron regulatory elements for tissue-specific alternative pre-mRNA splicing.

Alternative pre-mRNA splicing is a major cellular process by which functionally diverse proteins can be generated from the primary transcript of a single gene, often in tissue-specific patterns. The current study investigates the hypothesis that splicing of tissue-specific alternative exons is regulated in part by control sequences in adjacent introns and that such elements may be recognized via computational analysis of exons sharing a highly specific expression pattern. We have identified 25 brain-specific alternative cassette exons, compiled a dataset of genomic sequences encompassing these exons and their adjacent introns and used word contrast algorithms to analyze key features of these nucleotide sequences. By comparison to a control group of constitutive exons, brain-specific exons were often found to possess the following: divergent 5' splice sites; highly pyrimidine-rich upstream introns; a paucity of GGG motifs in the downstream intron; a highly statistically significant over-representation of the hexanucleotide UGCAUG in the proximal downstream intron. UGCAUG was also found at a high frequency downstream of a smaller group of muscle-specific exons. Intriguingly, UGCAUG has been identified previously in a few intron splicing enhancers. Our results indicate that this element plays a much wider role than previously appreciated in the regulated tissue-specific splicing of many alternative exons.

Passively mode-locked Yb:KLu(WO4)2 oscillators.

We demonstrate passive mode locking based on the novel monoclinic double tungstate crystal Yb:KLu(WO4)2. We report the shortest pulses ever produced with an Yb-doped tungstate laser using a semiconductor saturable absorber. A pulse duration of 81 fs has been achieved for an average power of 70 mW at 1046 nm. We compare the performance of the polarization oriented parallel to the Nm- and Np-crystallo-optic axes. Results in the femtosecond and picosecond regime are presented applying either Ti:sapphire or diode laser pumping. The great potential of Yb:KLu(WO4)2 as an active medium for ultrashort pulses is demonstrated for the first time, to our knowledge.

Cytotoxicity of radiocontrast agents on polarized renal epithelial cell monolayers.

OBJECTIVE: Radiocontrast-induced nephropathy is a clinically important complication of coronary angiography. The cellular mechanisms of radiocontrast-induced renal dysfunction are not clear. Since tubular transport functions depend on the polarity of renal epithelial cells, we investigated the effects of radiocontrast agents on polarized tubular cells in vitro. METHODS: We studied the effects of iso-iodine concentrations (37 and 74 mg iodine/ml) of an ionic (diatrizoate) and a non-ionic (iopamidol) monomeric radiocontrast agent and of hyperosmolal mannitol control solutions on filter-grown renal epithelial cell (MDCK, LLCPK) monolayers in vitro. The cytotoxicity was assayed by measurement of cell viability, transepithelial resistance, inulin permeability and (polarized) cellular enzyme release. The polarized MDCK cell phenotype was assessed by transmission electron microscopy and indirect immunofluorescence microscopy using monoclonal antibodies against specific apical (gp135) and basal (gp60, uvomorulin) MDCK surface markers. RESULTS: The radiocontrast agents reduced cell viability to a greater extent than hyperosmolal mannitol solutions in both cell lines; diatrizoate was more toxic than iopamidol. LLCPK cells were more susceptible to radiocontrast cytotoxicity than MDCK cells. This cytotoxicity was associated with an alteration of MDCK cell polarity as assessed by the redistribution of surface marker proteins. CONCLUSIONS: Diatrizoate is more toxic than iopamidol, which is partly related to its higher osmolality. The cytotoxicity of radiocontrast agents induces a redistribution of polarized membrane proteins which could contribute to the pathophysiology of radiocontrast-induced nephropathy.

Predictors of AIDS-preventive behavior among homosexually active men: a longitudinal study.

Predictors of adoption of safer sexual behaviors were examined in a cohort of 278 homosexually active men with stable HIV-antibody status followed over 12 months at a Boston community health center. The behaviors examined included: (1) restriction of partners to one monogamous or steady relationship and (2) among men who maintained multiple or non-steady partners, the avoidance of unprotected receptive and insertive anogenital contact. For each behavior, men who adopted consistently safer behavior were compared with those who remained unsafe, using bivariate analyses and multiple logistic regression modelling. The strongest predictor of all behaviors was the initial level of the unsafe behavior. After controlling for this, weak effects of several health beliefs were found, including perceived susceptibility and medical efficacy. Men who became aware of a positive HIV-antibody test result and who reported greater effort to change their behavior were more likely to adopt safer insertive anogenital contact. In this generally well-educated cohort with high levels of knowledge about AIDS, adoption of safer sexual behaviors is best predicted from previous levels of unsafe behavior.

Differential effects of two structurally related N6-substituted cAMP analogues on C6 glioma cells.

Membrane permeable derivatives of cAMP are widely used to investigate the role of cAMP in the regulation of cell growth and differentiation. To further investigate the molecular mechanisms, underlying the effects of cAMP analogues on growth control and differentiation, the concentration-dependent action of four structurally related cAMP analogues with substitutions at the N6-position in the adenine moiety, namely N6-benzyl-cAMP (Bn-cAMP), N6-benzoyl-cAMP (Bz-cAMP), N6-butyryl-cAMP (Bt-cAMP) and N6, O2'-cAMP (Bt2-cAMP), on C6 rat glioma cell proliferation was determined. The four analogues tested showed different specificities, and the order of growth inhibitory potency was: Bn-cAMP >> Bt-cAMP = Bt2-cAMP >> Bz-cAMP. Thus, although both derivatives have been described to equally bind and activate cAMP-dependent protein kinase (cAK) isozymes, Bn-cAMP most effectively inhibited C6 glioma cell proliferation with an IC50 of 25 microM, while Bz-cAMP was almost ineffective in C6 cells (IC50 >> 1000 microM). In vivo and in vitro studies using HPLC analysis, revealed that Bn-cAMP was subject to enzymatic degradation and that the metabolite Bn-adenosine (Bn-Ado) exerted growth inhibitory effects at a concentration even below 10 microM. Additionally, C6 glioma cells morphologically differentiated in the presence of Bn-cAMP (100 microM) and of Bn-Ado (10 microM), by extending long cellular processes. The growth inhibitory activity of Bn-Ado was not influenced, when dipyridamole, an inhibitor of adenosine uptake, was added to the incubation medium, indicating that adenosine action was mediated through a receptor-mediated mechanism.(ABSTRACT TRUNCATED AT 250 WORDS)

Ala335 is essential for high-affinity cAMP-binding of both sites A and B of cAMP-dependent protein kinase type I.

A single amino acid substitution (Ala335Asp) in cAMP binding site B of the regulatory subunit of cAMP-dependent protein kinase type I was sufficient to abolish high affinity cAMP binding for both cAMP binding sites A and B. Furthermore, the Ala335Asp mutation increased the activation constant for cAMP of the mutant holoenzyme 30-fold and also enhanced the rate of holoenzyme formation. Thus, the substitution was responsible for the dominant negative phenotype of the enzyme. Activation of mutant holoenzyme with site-selective cAMP analogs indicated that the enzyme dissociated through binding to site A only. Our results provide evidence that Ala335 is an essential residue for high affinity cAMP binding of both sites as well as for the functional integrity of the enzyme.

Use of drugs and alcohol by homosexually active men in relation to sexual practices.

The use of alcohol and recreational drugs in relationship to sexual practices was investigated longitudinally and cross-sectionally in a cohort of homosexually active men at a Boston community health center. Use of marijuana, nitrite inhalants, and cocaine decreased by approximately 25-48% during 42 months of follow-up, whereas use of alcohol showed little change. Men who initially reported both high-risk sexual practices and some use of alcohol or marijuana and who subsequently stopped using marijuana or reduced their frequency of alcohol use were significantly more likely to stop those unsafe sexual practices than were those who continued to use these substances. Men who at their most recent visit reported impaired judgement during sexual activity due to substance use, and particularly due to drug use, had significantly higher levels of perceived susceptibility to AIDS and barriers to behavior change, and lower levels of self-efficacy, which were independent of their unsafe sexual practices.

Recent bacterial and viral infection is a risk factor for cerebrovascular ischemia: clinical and biochemical studies.

We performed a case-control study to investigate the role of recent infection as stroke risk factor and to identify pathogenetic pathways linking infection and stroke. We examined 166 consecutive patients with acute cerebrovascular ischemia and 166 patients hospitalized for nonvascular and noninflammatory neurologic diseases. Control subjects were individually matched to patients for sex, age, and season of admission. We assessed special biochemical parameters in subgroups of stroke patients with and without recent infection (n = 21) who were similar with respect to demographic and clinical parameters. Infection within the preceding week was a risk factor for cerebrovascular ischemia in univariate (odds ratio [OR] 3.1; 95% confidence interval (CI), 1.57 to 6.1) and age-adjusted multiple logistic regression analysis (OR 2.9; 95% CI, 1.31 to 6.4). The OR of recent infection and age were inversely related. Both bacterial and viral infection contributed to increased risk. Infection elevated the risk for cardioembolism and tended to increase the risk for arterioarterial embolism. Stroke patients with and without preceding infection were not different with respect to factor VII and factor VIII activity, fibrin monomer, fibrin D-dimer, von Willebrand factor, C4b-binding protein, protein S, anticardiolipin antibodies, interleukin-1 receptor antagonist, soluble tumor necrosis factor-alpha receptor, interleukin-6, interleukin-8, and neopterin. In conclusion, recent infection is an independent risk factor for acute cerebrovascular ischemia. Its role appears to be more important in younger age groups. The pathogenetic linkage between infection and stroke is still insufficiently understood.