Automatic precursor-ion switching in a four-sector tandem mass spectrometer and its application to acquisition of the MS/MS product ions derived from a partially (18)O-labeled peptide for their facile assignments

We developed an acquisition processor unit to control MS1 and MS2 in a four-sector tandem mass spectrometer simultaneously. The magnetic field strength of MS1 corresponding to the precise centers of the precursor ions, whose masses are determined by MS1 in advance, is recalibrated using an appropriate standard just before an MS/MS experiment, which allows consecutive acquisition of the MS/MS spectra from multiprecursor ions by B2/E2-linked scanning of MS2 synchronized with automatic B1 switching to the centers of each precursor ion on MS1. The accuracy of the automatic precursor-ion switching and the efficiency of consecutive B2/E2-linked scannings were demonstrated by measurement of a peptide mixture. The new MS/MS control system was further applied to rapid acquisition of the MS/MS spectra of isotopic ions of MH+ and (M + 3)+ with normal oxygen and (18)O at the alpha-carboxyl group of a partly (18)O-labeled peptide, which can be easily prepared by enzymatic hydrolysis of a protein in buffer containing 40 atom % H2(18)O. MS/MS analysis of an (18)O-labeled peptide by the present system allowed facile and reliable assignment of MS/MS product ions to a peptide sequence. The usefulness of the method was also demonstrated by measurement of some peptides that give MS/MS product ions incidentally observed at the same mass or assignable to some incorrect sequence.

Alcoholic beverage consumption and risk of breast cancer in Spain

The relation between alcoholic beverage consumption and risk of breast cancer was examined. We used data from a population-based, case-control study that included almost all incident cases occurring in five Spanish regions from February 1990 to July 1991. A total of 762 women between 18 and 75 years of age, with a histologically confirmed, first diagnosis of breast cancer, were compared with 988 control women. Alcoholic beverage intake was measured by an interviewer-administered, semiquantitative food-frequency questionnaire. We used 'nondrinkers' as the reference category and divided the remainder into four categories according to alcohol intake. The multiple logistic analyses included not only alcohol intake but also possible confounding factors such as total caloric intake, age, socioeconomic status, and reproductive and medical histories. Even at moderate levels of alcohol intake (less than 8 g/day), a 50 percent increase in risk of breast cancer was found. The trend across categories of intake was statistically significant for wine and distilled drinks, as well as total alcohol intake. Consumption of 20 g or more of alcohol per day was associated with a 70 percent elevation in breast cancer risk compared with that of nondrinkers (adjusted relative risk (RR) = 1.7, 95 percent confidence interval = 1.3-2.3). Although the magnitude of the RR observed in our study was modest, our findings provide further support for a positive association between alcohol consumption and risk of breast cancer.

Follicle-stimulating hormone and human chorionic gonadotropin induced changes in granulosa cell glycosyl-phosphatidylinositol concentration

In the present investigation, a hCG sensitive glycosyl-phosphatidylinositol (GPI) was isolated from cultured rat granulosa cells obtained from the ovaries of diethylstilbestrol (DES) implanted immature rats. The inositol-phosphoglycan (IPG) moiety of the GPI-lipid contains galactose, glucosamine, and myoinositol as demonstrated by metabolic labelling of granulosa cells for different time periods (5-96 h) with [3H]galactose, [3H]glucosamine, or [3H]myoinositol and treatment of the purified [3H]GPI with phosphatidylinositol-specific phospholipase C. Labelling equilibrium of the GPI-lipid was achieved after 24 h ([3H]galactose and [3H]myoinositol) or 72 h ([3H]glucosamine) incubation, whereas incorporation of other labelled carbohydrates tested ([3H]galactosamine, [3H]mannose, and [3H]sorbitol) was negligible throughout the time period studied. The glucosamine C-1 appears to be linked through a glycosidic bond to the myoinositol molecule of the IPG moiety as revealed by the generation of phosphatidylinositol (PtdIns) after nitrous acid deamination of dual labelled ([3H]glucosamine/[14C]palmitate or [3H]glucosamine/[14C]myristate) glycosyl-phosphatidylinositol. To investigate the fatty acid composition of the diacylglycerol (DAG) backbone of the GPI, granulosa cells were also labelled (5-72 hr) with [14C]linoleate, [3H]myristate, [3H]oleate, [3H]palmitate, or [3H]stearate and the radioactivity associated with the purified glycosyl-phosphatidylinositol determined. Incorporation of [3H]palmitate and [3H]myristate into the GPI-lipid peaked after 8 h and 24 h of labelling, respectively, and both fatty acids were partially released after PLA2 treatment of the dual labelled ([3H]glucosamine/[14C]palmitate or [3H]glucosamine/[14C]myristate) GPI. In parallel experiments no significant incorporation of labelled stearate, oleate, or linoleic acid into the DAG backbone of the glycosylphosphatidylinositol could be detected. Granulosa cells were also labelled with [3H]glucosamine in the presence of FSH (30 ng/ml), cholera toxin (1 microgram/ml), or the membrane permeable cAMP analog (but)2cAMP (1 mM). Time related increases in GPI-labelling were apparent after 48 h and reached a maximum level (3-, 5-, and 7-fold for FSH, CT, and (but)2cAMP, respectively) after 72 h in culture. In another set of experiments, granulosa cells were labelled for 72 h with [3H]glucosamine in the presence of (but)2cAMP (1 mM), TPA (10(-7) M), or combination thereof. The effect of treatment with the membrane permeable cAMP analog on GPI labelling was prevented in the presence of TPA, whereas no differences in [3H]GPI content could be observed in untreated granulosa cells or cells cultured in the presence of the protein kinase C-activating phorbol ester alone.(ABSTRACT TRUNCATED AT 400 WORDS)

Acute upper gastrointestinal bleeding in Jerusalem 1988-91: causes, characteristics and relation to nonsteroidal anti-inflammatory drugs

We analyzed 321 consecutive episodes of community-based acute upper gastrointestinal bleeding admitted to the Hadassah University Hospital in Jerusalem during 1988-91. Of these 71% were in males aged 56.2 +/- 1.2 years (mean +/- SE) and 29% were in females (67.9 +/- 1.7 years, P < 0.001). The main diagnoses were duodenal ulcer (39.5%), gastric ulcer (16.9%), esophageal varices (10.0%), erosive gastritis (8.2%) and esophagitis (7.5%). The distribution of these diagnoses differed significantly between the genders (P = 0.0003). In males the prevalence of duodenal ulcer and of esophageal varices was higher, and that of gastric ulcer and esophagitis lower, than in females. Gastric ulcer patients were oldest, were the least likely to have received anti-ulcer medications prior to admission, and had the highest levels of urea and the lowest levels of hemoglobin on admission. Use of nonsteroidal anti-inflammatory drugs increased significantly with age and was reported in 35% of the cases (aspirin in doses < 1.0 g/day in 21%, nonsalicylate anti-inflammatory agents in 11%, aspirin plus other anti-inflammatory drugs in 3%). Use of systemic corticosteroids was reported in 4%. The most distinctive features of the population with acute upper gastrointestinal bleeding in the present study compared to other series were the significantly higher proportion of duodenal ulcers and the lower proportion of Mallory-Weiss tears.

The 35/50 kDa surface antigen of Trypanosoma cruzi metacyclic trypomastigotes, an adhesion molecule involved in host cell invasion

We have previously shown that monoclonal antibodies directed to the 90 kDa glycoprotein and the 35/50 kDa glycoconjugate, present on the surface of Trypanosoma cruzi metacyclic trypomastigotes, inhibited host cell invasion. Here we investigated whether these molecules could be the ligands for the target cell receptor. Binding assays were performed by incubating Vero cells with sonicated parasite extract. Detection of bound parasite components was carried out by using monoclonal antibodies (MoAbs) IG7 and 10D8, which recognize the 90 kDa and the 35/50 kDa antigens respectively. These experiments revealed that the 35/50 kDa glycoconjugate of metacyclic forms, but not the 1G7-reactive antigen, binds to Vero cells. The purified 35/50 kDa antigen bound to Vero cells and inhibited the entry of metacyclic forms in a dose-dependent manner. Although to a lesser extent, an immunologically related 35/50 kDa antigen of non-infective epimastigotes also bound to Vero cells but it was unable to inhibit parasite penetration at a concentration (100 micrograms/ml) in which metacyclic antigen exhibited more than 60% inhibition. All these data suggest that the metacyclic 35/50 kDa surface glycoconjugate is a ligand to the host cell in the process of T. cruzi invasion.

Seasonal fluctuations in acute upper gastrointestinal bleeding: lack of effect of nonsteroidal anti-inflammatory drugs

The seasonal pattern of community-based acute bleeding from the upper gastrointestinal (UGI) tract was studied prospectively in 1988-1991. Out of 3343 emergency admissions to the Departments of General Surgery, 321 (9.6%) were due to acute UGI bleeding. There was a significant monthly variation in the total number of admissions, as well as in the number of admissions due to acute UGI bleeding (p < 0.0001). However, there was no correlation between the two. Significant seasonal fluctuations were noted both in the absolute number of admissions due to acute UGI bleeding and in the percentage of UGI bleeding admissions of the total number of admissions to the Departments of General Surgery (p = 0.0002). During summer (July through September), the incidence declined significantly to a nadir of 5.5% of total number of admissions in July. The seasonal fluctuation correlated closely with the incidence of duodenal ulcer, but not with that of gastric ulcer. The seasonal pattern was consistent both in patients who had used aspirin or other nonsteroidal anti-inflammatory drugs as well as in those who had not.

Diacylglycerol rather than Ca2+ mediates GnRH inhibition of FSH induced steroidogenesis in ovarian granulosa cells

Treatment of cultured granulosa cells with PLC or GnRH stimulated the rapid generation of DAG and phosphoinositide turnover. The PKC activators PLC (3 mU/ml) and TPA (10(-7)M) or the decapeptide GnRH (10(-6)M) elicited similar inhibitory responses on FSH or cAMP stimulated granulosa cell steroidogenesis. Mobilization of intracellular Ca2+ with A23187 (10(-8)M) was followed by a slight increase in the steroidogenic activity of cultured granulosa cells, whereas elevation of extracellular K+ (50 mM) largely augmented the steroid biosynthetic activity of the granulosa cells. These results suggest that the inhibitory effect of GnRH on granulosa cell steroidogenesis is mediated by generation of DAG, rather than by increases in intracellular Ca2+ concentrations.

Measuring the use of mammography: two methods compared

Population studies often estimate mammography use using women's self-reports. In one North Carolina county, we compared self-report surveys with a second method--counting mammograms per population--for 1987 and 1989. Estimates from self-reports (35% in 1987, 55% in 1989) were considerably higher than those from mammogram counts (20% in 1987, 36% in 1989). We then confirmed 66% of self-reports in the past year. Self-reported use is more accurate regarding whether a woman has had a mammogram than when she had it, but self-reports accurately measure change over time.

A method for determination of N-glycosylation sites in glycoproteins by collision-induced dissociation analysis in fast atom bombardment mass spectrometry: identification of the positions of carbohydrate-linked asparagine in recombinant alpha-amylase by treatment with peptide-N-glycosidase F in 18O-labeled water

Previously, a combined use of fast atom bombardment (FAB) mass spectrometry and peptide N-glycosidase F, an enzyme that cleaves the beta-aspartylglycosylamine linkage of Asn-linked carbohydrates, was successfully applied to identification of N-glycosylation sites in a glycoprotein with the known or DNA-derived sequence (S. A. Carr and G. D. Roberts, 1986, Anal. Biochem. 157, 396-406). Here, we extended the method for easier identification of N-glycosylation sites in a glycoprotein even with unknown sequence. The glycoprotein is digested with peptide-N-glycosidase F in buffer containing 40 at% H2 18O, to yield a deglycosylated protein whose carbohydrate-linked Asn residues are converted to Asp partly labeled with 18O at their beta-carboxyl group during this digestion. The deglycosylated protein is further digested with proteolytic enzymes in an appropriate buffer prepared with normal water, and then peptides are separated on a reversed-phase column by HPLC. Peptides in which carbohydrate-linked Asn has been converted to Asp show a pair of signals ([M + 1]+ and [M + 3]+) in FAB mass spectra due to the partial incorporation of 18O into the beta-carboxyl groups of Asp residues, while the other peptides show normal isotopic ion distributions. Thus, both formally N-glycosylated peptides and, using collision-induced dissociation analysis, N-glycosylation sites can be identified. The application of the present method to the determination of N-glycosylation sites in a recombinant glycoprotein, Bacillus licheniformis alpha-amylase, is described.

A new type of mitogenic factor produced by Streptococcus pyogenes

A new type of mitogenic factor (protein) was purified from the culture supernatant of a strain of Streptococcus pyogenes by SP-Sephadex C-25 column chromatography, preparative isoelectric focusing and reversed-phase high-performance liquid chromatography. The purified factor, showing marked mitogenic activity in rabbit peripheral blood lymphocytes, gave a single-band staining for protein on SDS-PAGE. The molecular weight of the purified mitogenic factor was determined to be 25,370, which was different from those calculated from reported amino acid sequences deduced from 4 different nucleotide sequences of 3 kinds of streptococcal pyrogenic exotoxins (two SPEAs, SPEB and SPEC). The amino acid sequence of the N-terminal region of the purified mitogenic factor was determined to be Gln-Thr-Gln-Val-Ser-Asn-Asp-Val-Val-Leu-Asn-Asp-Gly-Ala-Ser-Lys-Tyr-Leu- Asn-Glu - Ala-, which was also different from the reported N-terminal sequences deduced from the 4 different nucleotide sequences. These data indicate that this mitogenic factor is distinct from the already described streptococcal pyrogenic exotoxins.

Diagnostic value of telescoping plugged catheters in HIV-infected patients with pulmonary infiltrates

To assess the diagnostic value of telescoping plugged catheters (TPC) in human immunodeficiency virus (HIV)-infected patients with pulmonary infiltrates (PI), we performed a prospective clinical study in 71 episodes of fever and PI in 66 HIV-infected patients (five patients had two different episodes of fever and PI). A control group of 12 HIV-infected patients with fever and normal chest roentgenogram was also studied. In all patients and prior to antibiotic treatment (except in mechanically ventilated patients), a TPC using quantitative cultures (cutoff point established at 10(3) CFU/ml) and a bronchoalveolar lavage (BAL) sampling were performed via fiberoptic bronchoscope. The overall incidence of bacterial pneumonia in the study group was 21 percent. The TPC cultures resulted in a microbiologic diagnosis of bacterial pneumonia in eight patients (11 percent) from the study group and in one patient (8 percent) from the control group. The TPC sensitivity in diagnosing bacterial infections was 53 percent and specificity was 76 percent. Negative predictive value was 85 percent and positive predictive value was 38 percent. By means of BAL, 35 episodes from the study group and two from the control group were diagnosed as nonbacterial or mycobacterial pulmonary infections. Considering TPC and BAL together, diagnosis was performed in 42 cases of PI (59 percent). Twenty percent (17/83) of HIV-infected patients suffered from bacterial colonization of their lower airways (a TPC culture greater than or equal to 10(3) CFU/ml without clinical evidence of bacterial infection). We conclude that the combined use of TPC and BAL may be useful in HIV-infected patients with PI, since this combined use allows the proper diagnosis of bacterial and nonbacterial infections, thereby increasing the overall diagnostic accuracy. To distinguish bacterial colonization from pulmonary infection in HIV-infected patients with PI, the cutoff point of quantitative cultures of TPC may be 10(4) CFU/ml.

Epidemiology of bluetongue viruses in the American tropics. Regional Bluetongue Team

A study of the epidemiology of bluetongue viruses is in progress with the collaboration of 11 Central American and Caribbean countries. To date, over 200 bluetongue virus isolates have been obtained from cattle and sheep in sentinel groups distributed in the participating countries. Bluetongue serotypes identified include 1, 3, 6, and 12, virus types not previously recorded in the Western Hemisphere. Although the clinical impact of bluetongue virus infections in this hyperendemic environment appears to be minimal, the ubiquity of infection causes restrictions on the export of ruminant livestock and germ plasm. The stability of the Caribbean region ecosystem and the long-range implications of the interface with the northern temperate bluetongue virus ecosystem are reviewed.

Use of bioelectrical impedance to assess body composition changes at high altitude

This study determined the feasibility of using bioelectrical impedance analysis (BIA) to assess body composition alterations associated with body weight (BW) loss at high altitude. The BIA method was also evaluated relative to anthropometric assessments. Height, BW, BIA, skinfold (SF, 6 sites), and circumference (CIR, 5 sites) measurements were obtained from 16 males (23-35 yr) before, during, and after 16 days of residence at 3,700-4,300 m. Hydrostatic weighings (HW) were performed pre- and postaltitude. Results of 13 previously derived prediction equations using various combinations of height, BW, age, BIA, SF, or CIR measurements as independent variables to predict fat-free mass (FFM), fat mass (FM), and percent body fat (%Fat) were compared with HW. Mean BW decreased from 84.74 to 78.84 kg (P less than 0.01). As determined by HW, FFM decreased by 2.44 kg (P less than 0.01), FM by 3.46 kg (P less than 0.01), and %Fat by 3.02% (P less than 0.01). The BIA and SF methods overestimated the loss in FFM and underestimated the losses in FM and %Fat (P less than 0.01). Only the equations utilizing the CIR measurements did not differ from HW values for changes in FFM, FM, and %Fat. It was concluded that the BIA and SF methods were not acceptable for assessing body composition changes at altitude.

A one-minute oxidase test to detect Vibrio strains isolated from cultures on thiosulphate-citrate-bile salts-sucrose (TCBS) medium

Vibrio cholerae is oxidase positive, a primary characteristic used to differentiate it from Enterobacteriaceae. But false negative oxidase test results have been obtained with colonies from thiosulphate-citrate-bile salts-sucrose (TCBS) agar medium. A rapid oxidase test procedure is described here. This takes 1 min, avoids false negative results and the necessity to grow the bacteria in a general-purpose medium. The bacteria may be recovered after the test and used for further investigations.

Patient satisfaction with pharmacologic erection program

One hundred seventy-two patients on a pharmacologic erection program for male erectile dysfunction were sent a detailed questionnaire regarding their satisfaction using intracorporeal injection with vasoactive drugs. Sixty-seven percent of patients responded. Eighty-five percent of respondents said their sex life was improved. Eighty-eight percent would recommend penile self-injection to a friend whose complaint is impotence. Despite this, 49 percent of respondents were no longer using self-injections. The results from our detailed questionnaire suggest that the majority of the patients are quite satisfied with the erections achieved with intracorporeal injection of vasoactive drugs. The high dropout rate associated with such a program may be due to reasons other than the quality of erection achieved and sexual satisfaction derived from pharmacologic erections.

Laser recanalization of thrombosed arteries using thermal and/or modified optical probes; angiographic and angioscopic study

The degree of residual stenosis by fresh thrombus after laser recanalization was compared by use of angiography and angioscopy. Fifteen NZW rabbits were used. Occlusive fresh thrombus in rabbit aorta was produced by mechanical deendothelialization and external constrictions simulating clinical situations. Argon laser angioplasty using microlens-tipped optical fiber and/or 2 mm hot-tip probe was done to recanalize thrombosed aorta in 10 animals. Two-mm hybrid probe was used in 5. Percent area stenosis (% AST) was derived by use of the mean radius method obtained by angiography of stenotic segments in two orthogonal views and/or from angioscopy. All 15 totally occluded vessels with fresh thrombus were recanalized. Four minor perforations occurred. Following argon laser angioplasty with the microlens optical fiber, percent stenosis was reduced to 53% in diameter by angiography and 66 in % AST by angioscopy, and to 48% and 55 respectively following hot-tip probe. After laser angioplasty with the hybrid probe, residual stenosis by fresh thrombus was 37% in diameter on angiography and 63 in % AST on angioscopy. Mean percent AST was 62% with angiography and 52% with angioscopy, and there was no correlation between them (r = -0.028). Angioscopy provided cross-sectional topographic views of thrombosed lumen and showed charring and shrinkage of thrombus following laser angioplasty. This study suggests that (1) continuous-wave laser angioplasty using modified optical fibers can recanalize thrombotic vascular occlusion, (2) laser angioplasty by hot-tip probe could evacuate fresh thrombus more than microlens fiber on angioscopy, and (3) angiographic % AST did not correlate with angioscopic % AST.

Impairment of maximal bilirubin secretion by cyclosporin A in the rat

The effect of cyclosporin A on the maximal secretion of bilirubin was investigated in male Wistar rats. Following a saturating load of the pigment, intravenous administration of cyclosporin A as a single bolus (20 mg/kg) significantly reduced bile flow and bile acid secretion. The bilirubin secretory transport maximum was alos significantly reduced. The decreased excretion of the bile pigment corresponded both to bilirubin mono- and di-conjugates, the excretion of unconjugated bilirubin being slightly and non-significantly reduced. Plasma and liver bilirubin concentrations were significantly increased, while liver UDP-glucuronosyltransferase activity did not significantly differ between control and cyclosporin A-treated rats. Our data indicate that, although in cyclosporin A-treated rats there are no changes in the activities of others markers of hepatocellular dysfunction, the overall plasma to bile transfer of bilirubin is altered. The reduced hepatobiliary transport of the pigment is mainly caused by an impairment of its intracellular/canalicular transport.

Hepatic disposition of organic anions in rats infested with Fasciola hepatica

This study was undertaken to investigate the effects of subclinical fascioliasis at various stages of its development (3, 6, and 11 weeks after infestation with an oral dose of 20 metacercariae of Fasciola hepatica) on the hepatobiliary transport of organic anions in rats. Basal bile acid secretion was not significantly modified in infested rats as compared to the controls but there was a significantly increased bile flow in the 11-week group. In all infested rats, maximal biliary excretion and cumulative excretion of bromosulphthalein was significantly reduced, although there was a tendence to recovery in the 11-week infested group. Decreased biliary secretion was accompanied by increased plasma and liver concentrations of bromosulphthalein. Glutathione S-transferase activity was significantly reduced by Weeks 3 and 6 postinfestation. Liver glutathione concentration was significantly reduced in all infested rats. Maximal excretion of dibromosulphthalein, a compound not biotransformed in the liver, fell by Week 6 postinfestation and recovered a normal value thereafter. These results indicate that effects of experimentally induced fascioliasis on hepatic disposition of organic anions depend upon the stage of its development and that are a consequence of both metabolism and transport related factors.