Coprescribing proton pump inhibitors with other medications

Proton pump inhibitors, the treatment of choice for acid-related disorders, are often coadministered with other medications, sometimes with potentially adverse interactions. Although all agents studied may potentially interact with one proton pump inhibitor or another, a literature review documented adverse interactions for 10 medications in particular. Furthermore, 44% of people using proton pump inhibitors received another gastrointestinal drug. Although documented interactions involving these agents have been reported infrequently, the authors advise that physicians and pharmacists should recognize this possibility and watch for potentially problematic combination therapy.

Responses to repeated oral irritation by capsaicin, cinnamaldehyde and ethanol in PROP tasters and non-tasters

Both increases (sensitization) and decreases (desensitization) in oral irritation have been reported in response to repeated short-term stimulation by compounds such as capsaicin, zingerone and menthol. It is unclear why one irritant would show sensitization and another desensitization, and this is further complicated by substantial inter-individual variation in response patterns. These variations may be the result of individual differences such as that represented by sensitivity to 6-n-propylthiouracil (PROP), which has been associated with variation in the overall intensity of irritation. In addition, comparisons between irritants have almost always involved inter-study comparisons, entailing different subject groups and frequently different methods. In the studies reported here, responses to three irritants-capsaicin, cinnamaldehyde and ethanol-were examined as a function of PROP taster status. A common core of subjects also received all three irritants, allowing an assessment of the extent to which different response patterns between irritants seen previously were the result of different properties of the irritants themselves. Over a series of ten stimuli presented at 1 min intervals, PROP taster status differentiated subject responses on the basis of overall intensity, but not the pattern of responses over repeated stimulation. The group response to ethanol and cinnamaldehyde was desensitization, a pattern also shown by most of the individual subjects. In contrast, the group response to capsaicin was neither clear sensitization nor desensitization, reflecting much greater individual variability in response patterns. It is suggested that the time course to a single irritant stimulus largely determines between irritant response variations, while the inter-stimulus interval (ISI) used for a given irritant will have critical values for showing predominantly sensitization or desensitization.

Confusing tastes and smells: how odours can influence the perception of sweet and sour tastes

This study investigated the relationship between perception of an odour when smelled and the taste of a solution to which the odour is added as a flavorant. In Experiment 1 (E1) sweetness, sourness, liking and intensity ratings were obtained for 20 odours. Taste ratings were then obtained for sucrose solutions to which the odours had been added as flavorants. Certain odours were found to enhance tasted sweetness while others suppressed it. The degree to which an odour smelled sweet was the best predictor of the taste ratings. These findings were extended in Experiment 2 (E2), which included a second tastant, citric acid, and employed four odours from E1. The most sweet smelling odour, caramel, was found to suppress the sourness of citric acid and, as in E1, to enhance the sweetness of sucrose. Again, odours with low sweetness suppressed the sweetness of tasted sucrose. The study demonstrated that the effects of odours on taste perception are not limited to sweetness enhancement and apply to sour as well as sweet tastes. The overall pattern of results is consistent with an explanation of the taste properties of odours in terms of prior flavour-taste associations.

The fatty acid distribution in low density lipoprotein in diabetes

Atherosclerosis is commonly found in diabetes. There is an association between small dense low density lipoprotein (LDL) phenotype, which is more prevalent in the diabetic state, and atherosclerosis. Small dense LDL is more easily oxidised and it is possible that fatty acid compositional changes, particularly an increase in polyunsaturated fatty acids, could underlie this association. However, there is little information about fatty acids in the different LDL phenotypes in the literature. This study examined LDL subfraction composition in 18 non-insulin-dependent diabetic (NIDDM) patients and 11 control subjects. LDL was isolated and fractionated into LDL 1, 2 and 3 by density gradient ultracentrifugation. NIDDM patients had significantly more fatty acids in all LDL subfractions than control subjects (P<0.01). Palmitic and linoleic acid were significantly greater in all subfractions in the diabetic patients compared to control subjects (P<0.01) and palmitoleic and oleic acids were also greater in LDL1 and LDL2 in diabetic patients (P<0.01). We conclude that in NIDDM fatty acids are increased in all LDL subfractions and this may be the reason for the increased atherosclerosis in diabetes irrespective of phenotype.

The generalizability of capsaicin sensitization and desensitization

Studies using capsaicin-saturated filter papers have shown that the intensity of oral irritation tends to grow over successive samples, a phenomenon known as sensitization. If a hiatus of 5-15 min is then introduced, the intensity of irritation produced by a subsequent capsaicin stimulus is much reduced, and desensitization is said to have occurred. The use of other methodologies such as whole-mouth rinses, either with capsaicin or the irritants menthol or zingerone, have not consistently shown this response pattern, casting doubt on the extent to which sensitization and desensitization are general phenomena. Experiment 1 addressed this issue by comparing responses to whole-mouth rinses of 0.6 and 3 ppm capsaicin with those to 3 ppm capsaicin filter papers. Over an initial series of 10 samples, sensitization was evident but only for the 3 ppm capsaicin stimuli. Following a 10-min hiatus, desensitization was observed for all stimulus types. An examination of the data of individual subjects revealed considerable variability in response patterns over the initial 10 samples between subjects and, within subjects, between the filter paper and rinse stimuli, and between the test replications. Desensitization to the posthiatus stimuli was more consistent. A second experiment examined whether the capsaicin sensitization and desensitization shown by stimulation with filter papers or solutions also occurred in the context of the consumption of foods containing capsaicin. Two foods--soup and chili con carne--were consumed under conditions in which the rate of consumption was timed, as in Experiment 1, or was self-paced. In neither of the two conditions or foods was there strong evidence of sensitization, although, again, desensitization following a hiatus was evident. Substantial individual variability in response patterns was again apparent. There is thus no evidence for sensitization occurring during normal food consumption.

Cleavage of double-stranded copy RNA by RNase 1 and RNase T1 provides a robust means to detect p53 gene mutations in clinical specimens

Detecting somatic mutations in patient specimens is challenging because of the wide variation in quality and quantity of genomic DNA in clinically derived material. In cancer specimens, the challenge of detecting mutations is usually compounded by the presence of large numbers of nonmutated normal cells that dampen the relative signal that can be obtained from employing any mutation detection strategy. In the case of somatic mutations in the gene encoding the tumor suppressor, p53, a clinically useful mutation detection assay must be able to detect a wide variety of types of mutations scattered over five coding exons and their flanking intron sequences. This study examined the ability of a mutation detection strategy, termed NIRCA, to identify single-base mutations in the clinically relevant domain of the p53 gene. This strategy relies on RNase digestion-mediated cleavage of double-stranded copy RNA transcribed in vitro from polymerase chain reaction (PCR)-amplified genomic templates to detect mismatched base pairs resulting from hybridization of complimenting mutant and wild-type copy RNA strands. This assay system was found to robustly detect all twelve possible mismatches and the plus one and minus one frame shifts. Furthermore, the assay could detect mutations in clinical specimens when the mutant alleles composed as few as 4% of the total population of alleles isolated in bulk specimen genomic DNA. This mutation detection strategy worked efficiently in bladder, breast, colon and lung tumors as well as sediments from bladder cytology specimens.

Gastroesophageal reflux disease

The data indicate that gastroenterologists have higher (P < .05) utilization, covered charges, and prescription drug utilization per PTE than FPs/GPs with regard to patients with lowest-severity GERD. The data show that patients treated by an FP/GP have significantly lower PTE duration when compared with patients treated by gastroenterologists. Average overall charges for FPs/GPs are also significantly lower than average overall charges for gastroenterologists. Additionally, average prescription drug charges per PTE are lower for FPs/GPs than for gastroenterologists. An important consideration is the variation of practice patterns in the treatment of GERD. This analysis is not based on a controlled study; therefore, adjustments for patients demographic and geographic factors are necessary in order to provide further reliable analysis. Additional research in this area is worthwhile and may include a controlled comparison of practice patterns among PCPs and specialists in relation to the quality of care and cost effectiveness of treatments prescribed for GERD.

Salmonella typhimurium DT104: a virulent and drug-resistant pathogen

Salmonella typhimurium phage type (PT) or definitive type (DT) 104 is a virulent pathogen for humans and animals, particularly cattle. It has been isolated increasingly from humans and animals in the United Kingdom and several other European countries and, more recently, in the United States and Canada. Humans may acquire the infection from foods of animal origin contaminated with the infective organism. Farm families are particularly at risk of acquiring the infection by contact with infected animals or by drinking unpasteurized milk. The symptoms in cattle are watery to bloody diarrhea, a drop in milk production, pyrexia, anorexia, dehydration and depression. Infection may result in septicemic salmonellosis and, upon necropsy, a fibrinonecrotic enterocolitis may be observed. The infection occurs more commonly in the calving season than at other times. Feedlot cattle and pigs may also be affected. Prolonged carriage and shedding of the pathogen may occur. Symptoms in humans consist of diarrhea, fever, headache, nausea, abdominal pain, vomiting, and, less frequently, blood in the stool. Salmonella typhimurium DT104 strains are commonly resistant to ampicillin, chloramphenicol, streptomycin, sulfonamides, and tetracycline.

Genome-wide search for asthma susceptibility loci in a founder population. The Collaborative Study on the Genetics of Asthma

Founder populations offer many advantages for mapping genetic traits, particularly complex traits that are likely to be genetically heterogeneous. To identify genes that influence asthma and asthma-associated phenotypes, we conducted a genome-wide screen in the Hutterites, a religious isolate of European ancestry. A primary sample of 361 individuals and a replication sample of 292 individuals were evaluated for asthma phenotypes according to a standardized protocol. A genome-wide screen has been completed using 292 autosomal and three X-Y pseudoautosomal markers. Using the semi-parametric likelihood ratio chi2 test and the transmission-disequilibrium test, we identified 12 markers in 10 regions that showed possible linkage to asthma or an associated phenotype (likelihood ratio P < 0.01). Markers in four regions (5q23-31, 12q15-24.1, 19q13 and 21q21) showed possible linkage in both the primary and replication samples and have also shown linkage to asthma phenotypes in other samples; two adjacent markers in one additional region (3p24.2-22) showing possible linkage is reported for the first time in the Hutterites. The results suggest that even in founder populations with a relatively small number of independent genomes, susceptibility alleles at many loci may influence asthma phenotypes and that these susceptibility alleles are likely to be common polymorphisms in the population.

The telomere and telomerase: how do they interact?

The tandemly repeated DNA sequence of telomeres is typically specified by the ribonucleoprotein enzyme telomerase. Telomerase copies part of its intrinsic RNA moiety to make one strand of the telomeric repeat DNA. Recent work has led to the concept of a telomere homeostasis system. We have been studying two key physical components of this system: the telomere itself and telomerase. Mutating the template sequence of telomerase RNA caused various phenotypes: (1) mutating specific residues in the ciliate Tetrahymena and two yeasts showed that they are required for critical aspects of telomerase action; (2) certain mutated telomeric sequences caused a previously unreported phenotype, i.e. a strong anaphase block in Tetrahymena micronuclei; and (3) certain template mutations in the telomerase RNA gene of the yeast Kluyveromyces lactis led to unregulated telomere elongation, which in some cases was directly related to loss of binding to K. lactis Rap1p. Using K. lactis carrying alterations in the genes for Rap1p and other silencing components, we proposed a general model for telomere length homeostasis: namely, that the structure and DNA length of the DNA-protein complex that comprises the telomere are key determinants of telomerase access, and hence the frequency of action of telomerase, at the telomere.

Functionally interacting telomerase RNAs in the yeast telomerase complex

The ribonucleoprotein (RNP) enzyme telomerase from Saccharomyces cerevisiae adds telomeric DNA to chromosomal ends in short increments both in vivo and in vitro. Whether or not telomerase functions as a multimer has not been addressed previously. Here we show, first, that following polymerization, the telomerase RNP remains stably bound to its telomeric oligonucleotide reaction product. We then exploit this finding and a previously reported mutant telomerase RNA to demonstrate that, unexpectedly, the S. cerevisiae telomerase complex contains at least two functionally interacting RNA molecules that both act as templates for DNA polymerization. Here, functional telomerase contains at least two active sites.

Principals of design and evaluation of an information system for a department of respiratory medicine

OBJECTIVES

To evaluate a departmental computer system.

DESIGN

a. Direct comparison of the time taken to use a manual system with the time taken to use a computer system for lung function evaluation, loan of equipment and production of correspondence. b. Analysis of the accuracy of data capture before and after the introduction of the computer system. c. Analysis of the comparative running costs of the manual and computer systems.

SETTING

Within a department of respiratory medicine serving a hospital of 1323 beds.

MAIN OUTCOME MEASURES

a. Time taken to perform functions with the assistance of computerised methods, in comparison to the manual method used alone. b. Accuracy of data capture. c. Relative running costs.

RESULTS

a. The computer system (CS) was significantly faster than the manual system (MS) for lung function evaluation (CS = 7.63 min/test, MS = 12.25 min/test), loan of equipment (CS = 0.40 min/loan, MS = 2.07 min/loan), and checking for overdue equipment (CS = 0.49 s/record, MS = 9 s/record). The production of correspondence was slightly slower with the computer (CS = 9.30 min/letter, MS = 8.54 min/letter). b. All outpatient episodes, but only 43 of 65 (66%) of in-patient episodes, were captured. Lung function and managerial report data were accurate using both manual and computerised methods. The manual system for equipment loans was inefficient, and use of the computer resulted in the recovery of 221 nebulisers. c. Development costs for 1988-1990 were high (72,178 pounds). Only 1200 pounds to 1845 pounds per year was recovered directly from staff time saved by the computer but larger savings resulted from changes in work practice (4049-4765 pounds). After 10 years the projected deficit is 10,000 pounds per annum in running costs.

CONCLUSIONS

In comparison with the manual methods, the computer system has shown significant advantages which provide accurate information, with significant favourable effects on working practices. In evaluating computer systems used in clinical practice it is essential to ensure that the projected work practice benefits are achieved without unacceptable costs in staff time, inaccurate data and high financial outlay.

Telomerase RNA mutations in Saccharomyces cerevisiae alter telomerase action and reveal nonprocessivity in vivo and in vitro

The ribonucleoprotein enzyme telomerase adds telomeric DNA to chromosomal ends. In most eukaryotes the telomeric repeat units are repeated precisely, consistent with the action of a telomerase that faithfully copies its RNA template. In contrast, Saccharomyces cerevisiae telomeric repeats are degenerate, suggesting that its telomerase has unusual mechanistic properties. We mutated the S. cerevisiae telomerase RNA (TLC1) with a series of 3-base (GUG) substitutions in and next to the 17-nucleotide templating domain. All mutant telomerases were active in TLC1/tlc1 diploids and synthesized patterns of mixed wild-type and mutant telomeric repeats into telomeric DNA, consistent with nonprocessive action. Telomerase isolated from cells containing each mutated tlc1 allele by itself had altered reaction properties in vitro. One mutant template enzyme, 476GUG, was active in vivo and in vitro in the presence of wild-type TLC1 RNA but lacked detectable activity in its absence. Haploid tlc1-476GUG cells containing only this mutant tlc1 allele underwent senescence. Other tlc1 template region mutations allowed maintenance of shortened telomeres in vivo but altered specific enzymatic properties of telomerase in vitro, including induction of primer-template slippage (472GUG) or alteration of the 5' boundary of the template (467GUG). These data demonstrate that telomerase RNA bases influence enzyme activity profoundly, suggesting that their roles are not confined to serving simply as the template for this specialized reverse transcriptase.

Judgments of chemosensory mixtures in memory

Memory-based ratings of chemosensory mixtures produce response patterns similar to those observed perceptually. This finding is extended in two experiments. In the first, subjects mad judgments of sweetness, sourness and intensity in memory or with perceptually present combinations of sucrose and citric acid. Performance in both conditions was equivalent. Debriefing revealed some explicit knowledge about the way such mixtures interact. A second study investigated the relationship between such explicit knowledge and performance on the memory task. Here, subjects made the same ratings, but sampled, on separate days; (1) capsaicin alone, (2) a flavoured, sucrose, critic acid solution and imagined adding capsaicin, (3) the solution alone and (4) the solution actually with capsaicin. Performance was equivalent across the semi-mental and real mixture. Only sweetness was suppressed. Debriefing revealed that subjects thought all tastes and flavours were affected by capsaicin. Apart from extending previous findings, these studies suggest a role for both explicit and implicit memory processes in mental mixture judgments.

Desensitization to oral zingerone irritation: effects of stimulus parameters

In humans, repeated oral stimulation with the irritant capsaicin produces sensitization or desensitization, depending on the temporal relationship and, to a lesser extent, the intensity of the stimuli. We have previously shown that zingerone, an irritant present in ginger, shows only desensitization across repeated samples, as well as following a hiatus in stimulation. Because the time-course of zingerone irritation differs from that of capsaicin, it is likely that optimal temporal and other stimulation parameters may also be different. In Experiment 1, we examined the effects of stimulus intensity (0.5%, 1.0%, 2.0% zingerone) and the number of successive stimuli in a series on psychophysical responses to zingerone irritation within the series and following a 5-min hiatus. Experiment 2 examined the effect of the duration of this hiatus on desensitization and recovery. Desensitization was apparent across the initial series of stimuli in both experiments and, irrespective of zingerone concentration, in Experiment 1. Desensitization also occurred following the 5-min hiatus, evident primarily at the higher concentrations. Preceding the hiatus with 5 or 10 stimuli produced the greatest posthiatus desensitization, but a decrease in rated intensity was also evident following a single stimulus. Experiment 2 showed that the optimal hiatus for demonstrating desensitization was 5 min and that, by 15 min, recovery had begun. In both experiments, individual differences in response were marked, with some subjects showing sensitization and others little change in response across repeated zingerone stimuli. The origin of these differences is unclear but were shown to be relatively stable across multiple sessions.

Psychophysical responses to single and multiple presentations of the oral irritant zingerone: relationship to frequency of chili consumption

There are few data on the psychophysical properties of zingerone, one of the pungent components in ginger, particularly in contrast to capsaicin. The time-intensity characteristics of zingerone irritation were examined using high-frequency, intermediate-frequency, and low-frequency users of chili, who rated the intensity of whole-mouth rinses of 1% zingerone at 6-s intervals for 3 min. Maximum intensity was reached within the first 20 s, while the zingerone was in the mouth. At this stage, there were no differences between groups. Following expectoration at 30 s, frequent users showed a more rapid decline in rated intensity than did intermediate users, who showed a more rapid decline than infrequent users. Capsaicin sensitization and desensitization are dependent upon the interstimulus intervals (ISIs) used. A second experiment, also using groups of high-, intermediate-, and low-frequency chili users, examined whether sensitization to zingerone could be demonstrated using ISIs based on the point of maximum intensity observed in the first study. In contrast to sensitization effects found with capsaicin, slight desensitization was observed over 10 successive zingerone stimuli. Following a 5-min hiatus in stimulation, further desensitization was observed over 10 results point to the ability of zingerone to self-desensitize, although the effect is of a smaller magnitude than that of capsaicin. None of these effects varied as a function of chili use. Analysis of the qualities that constituted zingerone irritation found that the sensations produced are predominantly burning and warmth, making it qualitatively similar to capsaicin.

Effects of oral chemical irritation on tastes and flavors in frequent and infrequent users of chili

The studies reported here addressed the question of whether the pungent principle in chilies, capsaicin, suppresses taste and flavor intensity. Over a period of several minutes, groups of frequent and infrequent eaters of chili repeatedly rated the taste and flavor intensities of sweet and sour solutions that also contained either orange or vanilla flavor, and capsaicin at 0, 2, 4, and 16 ppm. As well as the intensity of the qualities while in the mouth, measures of the number of rating periods for the intensity to dissipate to zero, and the summed total intensity were also derived. Infrequent chili users rated the capsaicin burn as more intense than did the frequent users. With few exceptions, and for groups, sweetness was suppressed by the presence of capsaicin. By contrast, sourness was unaffected by capsaicin. Flavor intensities also showed suppression by capsaicin. High correlations between ratings of sweetness and flavor were found, suggesting that perceptual confusion between the two qualities may have been responsible for the flavor suppression. A second experiment examined the effects of capsaicin on ratings of strawberry flavor alone. This study produced little evidence of flavor suppression by capsaicin. These results are discussed in terms of an attentional model of capsaicin's effects.

Detection of toxin genes in Escherichia coli isolated from normal dogs and dogs with diarrhea

The etiology of acute, nonviral diarrhea in dogs is poorly understood. Enterotoxigenic and verotoxigenic Escherichia coli are causal agents of diarrhea in humans, pigs, and cattle, but the association of these toxigenic E. coli with diarrhea in dogs has not been explored to a significant extent. In this study, DNA hybridization and PCR amplification were used to identify the frequency with which the genes for E. coli enterotoxins (STap, STb, and LTI) and verotoxins (VT1 and VT2) occur in association with diarrhea in dogs. Genes for VT1 (8.9%), VT2 (22.2%), STa (26.7%), and STb (4.4%) were identified in E. coli cultured from feces of 20 of 45 dogs (44.4%) with diarrhea. Genes for VT2, STa, and STb were not identified in feces from normal dogs. Genes for VT1 were observed in similar proportions in fecal samples from diarrheic (8.9%) and normal (12.3%) dogs. Heat labile enterotoxin (LTI) was not detected in fecal samples from either diarrheic or normal dogs. Our results suggest that heat stable enterotoxins and VT2 may be causally associated with diarrhea in dogs. Dogs appear to be able to carry VT1-producing E. coli without showing overt signs of disease.

The effects of prior experience with capsaicin on ratings of its burn

The experiments reported here found that judgments of 'burn' intensity are affected by long-term memory (LTM). The implication of these findings for range-frequency theory and the role of LTM in intensity judgments are discussed.