Involvement of waaY, waaQ, and waaP in the modification of Escherichia coli lipopolysaccharide and their role in the formation of a stable outer membrane

The waaY, waaQ, and waaP genes are located in the central operon of the waa (formerly rfa) locus on the chromosome of Escherichia coli. This locus contains genes whose products are involved in the assembly of the core region of the lipopolysaccharide molecule. In the R1 core prototype strain, E. coli F470, there are nine genes in this operon, and all but waaY, waaQ, and waaP have been assigned function. In this study, the waaY, waaQ, and waaP genes were independently mutated by insertion of a non-polar antibiotic resistance cassette, and the structures of the resulting mutant core oligosaccharides were determined by chemical analyses and phosphorus-nuclear magnetic resonance spectroscopy. All three of these mutations were shown to affect the modification of the heptose region of the core, a region whose structure is critical to outer membrane stability. Mutation of waaY resulted in a core oligosaccharide devoid of phosphate on HepII. Mutation of waaQ resulted in loss of the branch HepIII residue on HepII and impeded the activity of WaaY. Mutation of waaP resulted in loss of phosphoryl substituents on HepI and obviated WaaQ and WaaY activity. Only mutation of waaP resulted in hypersensitivity to novobiocin and sodium dodecyl sulfate, a characteristic of deep-rough mutations.     

A novel amplicon at 8p22-23 results in overexpression of cathepsin B in esophageal adenocarcinoma

Cathepsin B (CTSB) is overexpressed in tumors of the lung, prostate, colon, breast, and stomach. However, evidence of primary genomic alterations in the CTSB gene during tumor initiation or progression has been lacking. We have found a novel amplicon at 8p22-23 that results in CTSB overexpression in esophageal adenocarcinoma. Amplified genomic NotI-HinfI fragments were identified by two-dimensional DNA electrophoresis. Two amplified fragments (D4 and D5) were cloned and yielded unique sequences. Using bacterial artificial chromosome clones containing either D4 or D5, fluorescent in situ hybridization defined a single region of amplification involving chromosome bands 8p22-23. We investigated the candidate cancer-related gene CTSB, and potential coamplified genes from this region including farnesyl-diphosphate farnesyltransferase (FDFT1), arylamine N-acetyltransferase (NAT-1), lipoprotein lipase (LPL), and an uncharacterized expressed sequence tag (D8S503). Southern blot analysis of 66 esophageal adenocarcinomas demonstrated only CTSB and FDFT1 were consistently amplified in eight (12.1%) of the tumors. Neither NAT-1 nor LPL were amplified. Northern blot analysis showed overexpression of CTSB and FDFT1 mRNA in all six of the amplified esophageal adenocarcinomas analyzed. CTSB mRNA overexpression also was present in two of six nonamplified tumors analyzed. However, FDFT1 mRNA overexpression without amplification was not observed. Western blot analysis confirmed CTSB protein overexpression in tumor specimens with CTSB mRNA overexpression compared with either normal controls or tumors without mRNA overexpression. Abundant extracellular expression of CTSB protein was found in 29 of 40 (72. 5%) of esophageal adenocarcinoma specimens by using immunohistochemical analysis. The finding of an amplicon at 8p22-23 resulting in CTSB gene amplification and overexpression supports an important role for CTSB in esophageal adenocarcinoma and possibly in other tumors.     

Biological action of leptin as an angiogenic factor

Leptin is a hormone that regulates food intake, and its receptor (OB-Rb) is expressed primarily in the hypothalamus. Here, it is shown that OB-Rb is also expressed in human vasculature and in primary cultures of human endothelial cells. In vitro and in vivo assays revealed that leptin has angiogenic activity. In vivo, leptin induced neovascularization in corneas from normal rats but not in corneas from fa/fa Zucker rats, which lack functional leptin receptors. These observations indicate that the vascular endothelium is a target for leptin and suggest a physiological mechanism whereby leptin-induced angiogenesis may facilitate increased energy expenditure.     

Epidemiology of congenital diaphragmatic hernia, Hawaii, 1987-1996

Congenital diaphragmatic hernias (CDHs) in Hawaii between 1987 and 1996 were examined with data from a birth defects surveillance system. There were 51 cases of CDH (prevalence 2.45 per 10,000 births). Forty-nine percent of livebirths survived, an increase over the rate reported in Hawaii in 1975-1982. These results are similar to those reported by other population-based studies.     

Reduced central serotonin transporters in alcoholism

OBJECTIVE: Dysfunction of monoamine uptake mechanisms has been implicated in the pathogenesis of alcohol dependence. The authors explored whether serotonergic dysfunction is associated with anxiety and depression, which increase the risk of relapse in alcoholics. METHOD: The availability of serotonin and dopamine transporters in 22 male alcoholics and 13 healthy male volunteers was measured with the use of [123I] beta-CIT and single photon emission computed tomography, and psychopathological correlates were assessed. RESULTS: A significant reduction (a mean of about 30%) in the availability of brainstem serotonin transporters was found in the alcoholics, which was significantly correlated with lifetime alcohol consumption and with ratings of depression and anxiety during withdrawal. CONCLUSIONS: The findings support the hypothesis of serotonergic dysfunction in alcoholism and in withdrawal-emergent depressive symptoms.     

Prenatal diagnosis of holoprosencephaly. A series of twelve cases

OBJECTIVE OF THE STUDY: To determine the prenatal ultrasound criteria of holoprosencephaly and their correlation with embryogenesis. MATERIAL AND METHODS: We report 12 cases of holoprosencephaly that have been discovered between January 1990 and June 1996 (eleven alobar holoprosencephalies and one semilobar holoprosencephaly) at La Grave Hospital, Toulouse. RESULTS: In all cases, severe facial anomalies have been (cyclopia, cebocephaly or ethmocephaly). Prenatal ultrasound diagnosis was based on the association of brain anomalies (wide monoventricular cavity, thalami fusion, lacking of median structures) and facial dysmorphia (hypotelorism, orbital anomalies, median cleft lip ...). Finding microcephaly was a frequent sign of holoprosencephaly (64% of all cases). Chromosomal abnormalities have been found in 36% of the fetuses (Trisomy 13 is the most common). All patients underwent therapeutic abortions. CONCLUSION: Transvaginal sonography diagnosis can be made around the 14th to 16th week amenorrhea. An early diagnosis allows an easier pregnancy termination, when such severe anomalies are found. In order to provide genetic counseling, a cytogenetic study of the fetus is necessary.     

Significant reduction in the rate of false-negative cervical smears with neural network-based technology (PAPNET Testing System)

False-negative cervical Pap smears may lead to disability or death from carcinoma of the uterine cervix. New computer technology has led to the development of an interactive, neural network-based vision instrument to increase the accuracy of cervical smear screening. The instrument belongs to a new class of medical devices designed to provide computer-aided diagnosis (CADx). To test the instrument's performance, 487 archival negative smears (index smears) from 228 women with biopsy-documented high-grade precancerous lesions or invasive cervical carcinoma (index women) were retrieved from the files of 10 participating laboratories that were using federally mandated quality assurance procedures. Samples of sequential negative smears (total 9,666) were retrieved as controls. The instrument was used to identify evidence of missed cytological abnormalities, including atypical squamous or glandular cells of undetermined significance (ASCUS, AGUS), low-grade or high-grade squamous intraepithelial lesions (LSIL, HSIL) and carcinoma. Using the instrument, 98 false-negative index smears were identified in 72 of the 228 index women (31.6%, 95% confidence interval [CI]: 25% to 38%). Disregarding the debatable categories of ASCUS or AGUS, there were 44 women whose false-negative smears disclosed squamous intraepithelial lesions (SIL) or carcinoma (19.3%; 95% CI: 14.2% to 24.4%). Unexpectedly, SILs were also identified in 127 of 9,666 control negative smears (1.3%; 95% CI: 1.1% to 1.5%). Compared with historical performance data from several participating laboratories, the instrument increased the detection rate of SILs in control smears by 25% and increased the yield of quality control rescreening 5.1 times (P < 0.0001). These data provide evidence that conventional screening and quality control rescreening of cervical smears fail to identify a substantial number of abnormalities. A significant improvement in performance of screening of cervical smears could be achieved with the use of the instrument described in this report.     

Race, resource use, and survival in seriously ill hospitalized adults. The SUPPORT Investigators

OBJECTIVE: To examine the association between patient race and hospital resource use. DESIGN: Prospective cohort study. SETTING: Five geographically diverse teaching hospitals. PATIENTS: Patients were 9,105 hospitalized adults with one of nine illnesses associated with an average 6-month mortality of 50%. MEASUREMENTS AND MAIN RESULTS: Measures of resource use included: a modified version of the Therapeutic Intervention Scoring System (TISS); performance of any of five procedures (operation, dialysis, pulmonary artery catheterization, endoscopy, and bronchoscopy); and hospital charges, adjusted by the Medicare cost-to-charge ratio per cost center at each participating hospital. The median patient age was 65; 79% were white, 16% African-American, 3% Hispanic, and 2% other races; 47% died within 6 months. After adjusting for other sociodemographic factors, severity of illness, functional status, and study site, African-Americans were less likely to receive any of five procedures on study day 1 and 3 (adjusted odds ratio [OR] 0.70; 95% confidence interval [CI] 0.60, 0.81). In addition, African-Americans had lower TISS scores on study day 1 and 3 (OR -1.8; 95% CI-1.3, -2.4) and lower estimated costs of hospitalization (OR (-)$2,805; 95% CI (-)$1,672, (-)$3,883). Results were similar after adjustment for patients' preferences and physicians' prognostic estimates. Differences in resource use were less marked after adjusting for the specialty of the attending physician but remained significant. In a subset analysis, cardiologists were less likely to care for African-Americans with congestive heart failure (p < .001), and cardiologists used more resources (p < .001). After adjustment for other sociodemographic factors, severity of illness, functional status, and study site, survival was slightly better for African-American patients (hazard ratio 0.91; 95% CI 0.84, 0.98) than for white or other race patients. CONCLUSIONS: Seriously ill African-Americans received less resource-intensive care than other patients after adjustment for other sociodemographic factors and for severity of illness. Some of these differences may be due to differential use of subspecialists. The observed differences in resource use were not associated with a survival advantage for white or other race patients.     

Residual urine in 75-year-old men and women. A normative population study

To evaluate the therapeutic effects of high dose pulse oral calcitrol, 3.5 micrograms calcitrol three times a week and calcium carbonate were administered to 13 patients with end-stage renal disease on chronic hemodialysis with hyperparathyroidism refractory to conventional calcitrol therapy. Serum parathyroid hormone and osteocalcin were detected by radioimmunoassay. Serum parathyroid hormone level of the patients decreased from 1111 +/- 344 ng/L to 492 +/- 218 ng/L by 57.5 +/- 11.5 percent (P < 0.01) in 6 months after the beginning of treatment. Both serum alkaline phosphatase and osteocalcin levels declined markedly, and correlated positively with that of parathyroid hormone. Plasma calcium concentration was markedly elevated, but no obvious increase of plasma phosphate was found. High dose pulse oral calcitrol was effective on secondary hyperparathyroidism. During the course of treatment timely and individual adjustment of calcitrol dose and dialysate calcium concentration is essential.