Lower esophageal sphincter pressures and serum gastrin levels after cholinergic stimulation

To define the role of gastrin, if any, in the response of the lower esophageal sphincter (LES) to bethanechol, serum gastrin determinations and LES pressure measurements were made in controls, patients with vagotomy and antrectomy (V&A), and patients with vagotomy and pyloroplasty (V&P). Despite significant differences in mean basal serum gastrin levels no differences were found in mean resting LES pressures among these groups. In controls significant increases in LES pressure occurred after subcutaneous bethanechol, but serum gastrin levels did not change from basal values. Subcutaneous injections of bethanechol produced significantly greater increases in LES pressures in V&P patients than in V&A patients. Serum gastrin levels did not change in either group; however, background serum gastrin concentrations were significantly greater for V&P patients than V&A patients throughout the study. Intravenous infusion of human gastrin I heptadecapeptide in controls significantly increased sphincter responses to bethanechol. Thus, these studies provide evidence to suggest that the LES response to bethanechol is affected by background serum gastrin levels.     

Uterine activity in the multiparous patient

There were 149 parous patients with normal cervical dilatation patterns studied. The purpose was to quantitate and characterize uterine activity in a group of multiparous patients with normal labor using our present on-line method and to evaluate our method against pervious work done on uterine activity. A mean total of 5,299 uterine activity units (UAU) was required to progress from 4 cm. through delivery. In the patients receiving oxytocin 5,907 UAU were required and 4,498 UAU for those not receiving oxytocin. Of the total uterine work from 4 cm. to delivery, 49.4% was required to progress from 4 to 6 cm. 38.7% to progress from 6 to 10 cm., and 11.9% for the second stage. This study establishes in a quantitative way, using on-line methods, the patterns of uterine activity expended by the parous patient in normal labor and can be compared to previous off-line and manual evaluations. These data can be compared with the on-line observations previously made in a primiparous group, and will be fundamental to automated evaluations including definitions of abnormal labor.     

The influence of a mineralizing mouthrinse on the mineral contents and on the pH of dental plaque

The main objective of this study was to evaluate the effects of a single use of a mineralizing mouthrinse on dental plaque pH and on its mineral contents: an additional objective was to examine the effects of an oral prophylaxis and scaling on the same response variables. A total of 22 volunteer dental students (14 female and 8 male) participated in the study. The mineralizing mouthrinse contained calcium, phosphate, strontium and fluoride ions. Following a 48-hour period without oral hygiene and 2 hours after breakfast, dental plaque was collected twice from each participant for the evaluation of the effects of the oral prophylaxis and scaling, and twice more for the evaluation of the effects of the mineralizing mouthrinse. The pH was measured in vitro with a microelectrode and the mineral contents were determined by atomic emission spectrometry. The results demonstrate that the average post-prophylaxis pH was higher than the average pre-prophylaxis pH, and that a variation of the average contents of some minerals in the dental plaque was also observed after prophylaxis compared to the contents prior to prophylaxis. Although there was a significant reduction in the Fe content after the rinse with the mineralizing solution, no significant variation on the average pH was detected.     

Effect of Salmonella assay negative and positive carcinogens on intrachromosomal recombination in S-phase arrested yeast cells

A wide variety of carcinogens including Ames assay (Salmonella) positive as well as Salmonella negative carcinogens induce intrachromosomal recombination (DEL recombination) in Saccharomyces cerevisiae. We have shown previously that the Salmonella positive carcinogens, ethyl methanesulfonate (EMS), methyl methanesulfonate (MMS) and 4-Nitroquinoline-N-oxide (4-NQO, and the Salmonella negative carcinogens, safrole, benzene, thiourea, carbon tetrachloride, and urethane, induced DEL recombination in growing, in G1 and in G2 arrested yeast cells. Since we found interesting differences in response between dividing and arrested cells, we wanted to find out whether these differences were due to the difference between cell division versus cell cycle arrest or to any particular cell cycle phase. In the present paper we incubated cells in the presence of hydroxyurea (HU) for cell cycle arrest in S-phase and exposed them to the above carcinogens, and plated them onto selective medium to determine DEL and interchromosomal recombination (ICR) frequencies. It was surprising that carbon tetrachloride had no effect on DEL recombination or ICR in HU treated cells even though it induced DEL recombination in G1 and G2 arrested as well as dividing cells. Further experiments are in agreement with the interpretation that carbon tetrachloride was responsible for prematurely pushing G1 cells into S-phase. The consequence of this may be replication on a damaged template which may be responsible for the action of carbon tetrachloride. EMS, MMS, 4-NQO and urethane were more recombinagenic in HU treated cells than in previous experiments with G2 arrested cells. None of the carcinogens appeared to be activated by S9 for either DEL recombination or ICR induction. Furthermore, we only detect cytochrome P-450 in dividing but not in arrested cells, arguing that possible differences in the ability to metabolize the compounds does not explain the observed differences for DEL recombination induction in the different cell cycle phases. We discuss these data in terms of the mechanism of induced DEL recombination and the possible biological activities of these carcinogens.     

Improved risk stratification in unstable angina: identification of patients at low risk for in-hospital cardiac events by admission echocardiography

BACKGROUND: Current protocols for risk stratification of patients with acute chest pain syndromes rely on clinical parameters and are oriented toward identification of patients at high risk for adverse cardiac events; however, this paradigm for risk stratification does not adequately address the observation that adverse cardiac events are relatively uncommon in this population. In an era of cost containment, consideration also should be given to identification of patients at low risk for adverse cardiac events, who may be safely discharged without expensive inpatient hospitalization. HYPOTHESIS: The purpose of this study was to develop echocardiographic predictors that identify unstable angina patients at low risk for adverse cardiac events and that discriminate between low- and high-risk patients. METHODS: The predictive accuracy of retrospectively determined echocardiographic predictors were compared in a population-based sample of 66 consecutive unstable angina patients undergoing echocardiography within 24 h of admission. RESULTS: Echocardiographic predictors of adverse events included wall motion score index > or = 0.2, ejection fraction < or = 40%, and mitral regurgitation severity > 2. One or more echocardiographic predictors of adverse events were present in 32 patients (48%). A composite echocardiographic predictor of adverse events was specific, had a high positive predictive value for the identification of high-risk patients, and discriminated between unstable angina patients at high and low risk for adverse cardiac events. CONCLUSION: Echocardiographic predictors of adverse events are specific and discriminate between unstable angina patients at high and low risk for adverse cardiac events.     

Evidence for a phase transition in the early development of prehension

The genotoxicity of twenty one clinically used (or discontinued) antihistamines is reviewed. New results are also presented from an evaluation of selected antihistamines in the V79 in vitro micronucleus assay. For two antihistamines, no genotoxicity data is available. Of the remaining nineteen, nine have been reported as positive and one equivocal in at least one genotoxicity assay despite the fact that none possess structural alerts for genotoxicity. Ethidium displacement and bleomycin amplification studies in V79 cells indicate that nine of these ten antihistamines are capable of intercalative DNA binding. Further, nine of the ten positive compounds, but none of the tested compounds which also intercalate but are reported to be negative in gene-tox assays (e.g. triprolidine, chlorcyclizine, clemastine), possess a dimethylamino substituent suggesting the requirement for this cationic function in the genotoxicity. It is proposed that the apparent genotoxicity of antihistamines and possibly many other pharmaceuticals derives from a hitherto unappreciated propensity of these drugs for stabilized intercalative DNA binding. It is further proposed that the bleomycin amplification assay may provide a widely applicable means for assessing functional intercalative drug/DNA interaction in intact mammalian cells.