Checkpoint kinases regulate a global network of transcription factors in response to DNA damage.

DNA damage activates checkpoint kinases that induce several downstream events, including widespread changes in transcription. However, the specific connections between the checkpoint kinases and downstream transcription factors (TFs) are not well understood. Here, we integrate kinase mutant expression profiles, transcriptional regulatory interactions, and phosphoproteomics to map kinases and downstream TFs to transcriptional regulatory networks. Specifically, we investigate the role of the Saccharomyces cerevisiae checkpoint kinases (Mec1, Tel1, Chk1, Rad53, and Dun1) in the transcriptional response to DNA damage caused by methyl methanesulfonate. The result is a global kinase-TF regulatory network in which Mec1 and Tel1 signal through Rad53 to synergistically regulate the expression of more than 600 genes. This network involves at least nine TFs, many of which have Rad53-dependent phosphorylation sites, as regulators of checkpoint-kinase-dependent genes. We also identify a major DNA damage-induced transcriptional network that regulates stress response genes independently of the checkpoint kinases.

An α-diaminoboryl carbanion assisted stereoselective single-pot preparation of α,ß-disubstituted acrylonitriles.

An α-diaminoboryl carbanion-mediated one-pot olefination directly converts an acetonitrile or the homologous nitrile into a series of α,ß-disubstituted acrylonitriles in a stereoselective manner. The protocol involves the formation of an α-substituted α-diaminoboryl acetonitrile and subsequent olefination with an aldehyde. The use of an aryl or conjugated aldehyde preferentially leads to a (Z)-acrylonitrile, while an aliphatic aldehyde gave an (E)-isomer as a major product. Two complementary approaches, a linear method and a divergent method, are developed.

A facile, one-pot synthesis of beta-substituted (Z)-acrylonitriles utilizing an alpha-diaminoboryl carbanion.

A simple three-step single-pot procedure for Z-stereoselective synthesis of beta-monosubstituted acrylonitriles has been established. The reaction involves olefination of aldehydes with an in situ generated alpha-diaminoboryl carbanion species. Various aromatic and aliphatic aldehydes were smoothly converted into the corresponding (Z)-olefin products (up to 96:4 ratio) in good yields (80-98%).

A systems approach to delineate functions of paralogous transcription factors: role of the Yap family in the DNA damage response.

Duplication of genes encoding transcription factors plays an essential role in driving phenotypic variation. Because regulation can occur at multiple levels, it is often difficult to discern how each duplicated factor achieves its regulatory specificity. In these cases, a "systems approach" may distinguish the role of each factor by integrating complementary large-scale measurements of the regulatory network. To explore such an approach, we integrate growth phenotypes, promoter binding profiles, and gene expression patterns to model the DNA damage response network controlled by the Yeast-specific AP-1 (YAP) family of transcription factors. This analysis reveals that YAP regulatory specificity is achieved by at least three mechanisms: (i) divergence of DNA-binding sequences into two subfamilies; (ii) condition-specific combinatorial regulation by multiple Yap factors; and (iii) interactions of Yap 1, 4, and 6 with chromatin remodeling proteins. Additional microarray experiments establish that Yap 4 and 6 regulate gene expression through interactions with the histone deacetylase, Hda1. The data further highlight differences among Yap paralogs in terms of their regulatory mode of action (activation vs. repression). This study suggests how other large TF families might be disentangled in the future.

Renal failure resulting from infiltration by inflammatory myofibroblastic tumor responsive to corticosteroid therapy.

Inflammatory myofibroblastic tumor (IMT) is a rare disease of inflammatory and spindle cell proliferative lesions in multiple sites. Most frequently reported in the lungs, a variety of extrapulmonary sites have been described. We report the first case of IMT causing renal failure by massive bilateral renal infiltration. Renal function continued to deteriorate (peak serum creatinine level, 8.4 mg/dL) despite placement of a ureteral stent. The kidneys were diffusely enlarged on computed tomographic (CT) scan. Renal biopsy showed myofibroblastic proliferation and inflammatory infiltration. Renal failure responded favorably over weeks to corticosteroid therapy (serum creatinine level, 2.8 mg/dL) with a marked reduction in bilateral renal enlargement by CT scan.

Changes in acid secretion over the years. A 30-year longitudinal study.

We studied the effect of aging on gastric acid secretion in 11 physicians who had augmented histamine tests while at medical school in 1962. One of them had a duodenal ulcer at the time. The augmented histamine test was repeated in 1991 and, in addition, upper gastrointestinal endoscopy was done to exclude peptic ulcer and to obtain biopsies for histologic analysis and assessment of Helicobacter pylori status. The mean basal acid output decreased from 7.3 to 1.9 mEq/hr during the 30-year period of follow-up (p < 0.001), and the mean maximum acid output decreased from 29.9 to 20.3 mEq/hr (p < 0.01). The maximum acid output data showed a profound decrease in 4 of the 11 participants, a lesser decrease in 4, and a minimal increase in the remaining 3. Histologic analysis suggested a greater likelihood of atrophic gastritis, H. pylori infection, or both in participants showing a pronounced decrease in acid secretion with aging.

Autonomic neuropathy in extra-hepatic portal vein thrombosis: evidence for impaired autonomic reflex arc.

BACKGROUND/AIMS: Autonomic dysfunction is common in cirrhosis, and may be associated with increased mortality and hyperdynamic circulatory changes. Our aim was to investigate whether autonomic disturbances occur in extrahepatic portal vein thrombosis and their correlation with hemodynamic abnormalities. PATIENTS AND METHODS: Heart rate variation in response to standing, deep breathing, and Valsalva maneuver, and blood pressure response to sustained handgrip and to standing, were studied in 16 subjects with portal vein thrombosis (10 males, 30.8+/-2.8 years: mean+/-SE), 12 with cirrhosis (7 males, 52+/-2.3 years), and 10 healthy controls (7 males, 30.8+/-3.0 years). Supine resting, and 10- and 30-min standing epinephrine and norepinephrine levels were measured and results correlated with cardiac output. RESULTS: Autonomic dysfunction occurred in 62% of portal vein thrombosis and 75% of cirrhosis subjects, but in no controls (p<0.02). Similarly, postural hypotension occurred in portal vein thrombosis (-10.25+/-0.65 mmHg, p=0.003) and cirrhosis (-7.42+/-0.82 mmHg, p=0.007) but not in controls. All groups had similar baseline epinephrine and norepinephrine concentrations. Epinephrine increased significantly in controls (45%, p<0.01 and 49%, p<0.02) after 10 of 30 min standing but not in the portal vein thrombosis or the cirrhotic group, and norepinephrine increased after 10 and 30 min standing in cirrhotics (128%, p<0.004 and 130%, p<0.008) and controls (129%, p<0.002 and 116%, p<0.004), but not portal vein thrombosis (34.5% and 39%, NS vs baseline). Portal vein thrombosis and cirrhosis groups had increased cardiac output (4441+/-509 and 3262+/-292) vs controls (1763+/-212 ml/min/m2, p<0.002), but there was no correlation with autonomic neuropathy or with catecholamine levels. CONCLUSIONS: Autonomic dysfunction and impaired catecholamine response to orthostatic stress occur commonly in portal vein thrombosis and suggest an impairment of the autonomic reflex arc, but changes do not correlate with hemodynamic abnormalities.

Helicobacter pylori prevalence in non-ulcer dyspepsia--ethnic and socio-economic differences.

Helicobacter pylori is an important cause of gastritis and a number of therapeutic trials suggest that it may be important in the genesis of duodenal ulcer recurrence. The reported prevalence of gastric colonisation by the organism varies considerably. The aim of this cross-sectional survey was to determine its prevalence in non-ulcer dyspeptics and to determine whether this is influenced by age, race, sex, socio-economic status, educational level and the number of persons sharing accommodation. One hundred and sixty-nine patients underwent endoscopy; biopsy specimens were taken from the antrum and H. pylori status was determined histologically. Gastric colonisation was found in 106 patients (63%). The prevalence showed a marked ethnic difference: 40% in whites and 71% in coloureds (P < 0.001). The ethnic groups were characterised by significant differences in socio-economic status (P < 10(-6)), educational level (P < 10(-6)), number of persons sharing accommodation (P < 10(-6)) and age (P < 0.001). These same differences were found when comparing the H. pylori-positive and negative groups, but were less marked and could be attributed to the marked differences between ethnic groups. We conclude that H. pylori prevalence differs between the ethnic groups studied. This may be because of varying degrees of exposure risk.