Medication adherence prediction through temporal modelling in cardiovascular disease management

Background

Chronic conditions place a considerable burden on modern healthcare systems. Within New Zealand and worldwide cardiovascular disease (CVD) affects a significant proportion of the population and it is the leading cause of death. Like other chronic diseases, the course of cardiovascular disease is usually prolonged and its management necessarily long-term. Despite being highly effective in reducing CVD risk, non-adherence to long-term medication continues to be a longstanding challenge in healthcare delivery. The study investigates the benefits of integrating patient history and assesses the contribution of explicitly temporal models to medication adherence prediction in the context of lipid-lowering therapy.

Methods

Data from a CVD risk assessment tool is linked to routinely collected national and regional data sets including pharmaceutical dispensing, hospitalisation, lab test results and deaths. The study extracts a sub-cohort from 564,180 patients who had primary CVD risk assessment for analysis. Based on community pharmaceutical dispensing record, proportion of days covered (PDC) $$\ge$$ ≥  80 is used as the threshold for adherence. Two years (8 quarters) of patient history before their CVD risk assessment is used as the observation window to predict patient adherence in the subsequent 5 years (20 quarters). The predictive performance of temporal deep learning models long short-term memory (LSTM) and simple recurrent neural networks (Simple RNN) are compared against non-temporal models multilayer perceptron (MLP), ridge classifier (RC) and logistic regression (LR). Further, the study investigates the effect of lengthening the observation window on the task of adherence prediction.

Results

Temporal models that use sequential data outperform non-temporal models, with LSTM producing the best predictive performance achieving a ROC AUC of 0.805. A performance gap is observed between models that can discover non-linear interactions between predictor variables and their linear counter parts, with neural network (NN) based models significantly outperforming linear models. Additionally, the predictive advantage of temporal models become more pronounced when the length of the observation window is increased.

Conclusion

The findings of the study provide evidence that using deep temporal models to integrate patient history in adherence prediction is advantageous. In particular, the RNN architecture LSTM significantly outperforms all other model comparators.

Association of Continuity of Primary Care and Statin Adherence

Purpose

Deficiencies in medication adherence are a major barrier to effectiveness of chronic condition management. Continuity of primary care may promote adherence. We assessed the association of continuity of primary care with adherence to long-term medication as exemplified by statins.

Research Design

We linked data from a prospective study of 267,091 Australians aged 45 years and over to national data sets on prescription reimbursements, general practice claims, hospitalisations and deaths. For participants having a statin dispense within 90 days of study entry, we computed medication possession ratio (MPR) and usual provider continuity index (UPI) for the subsequent two years. We used multivariate Poisson regression to calculate the relative risk (RR) and 95% confidence interval (CI) for the association between tertiles of UPI and MPR adjusted for socio-demographic and health-related patient factors, including age, gender, remoteness of residence, smoking, alcohol intake, fruit and vegetable intake, physical activity, prior heart disease and speaking a language other than English at home. We performed a comparison approach using propensity score matching on a subset of the sample.

Results

36,144 participants were eligible and included in the analysis among whom 58% had UPI greater than 75%. UPI was significantly associated with 5% increased MPR for statin adherence (95% CI 1.04–1.06) for highest versus lowest tertile. Dichotomised analysis using a cut-off of UPI at 75% showed a similar effect size. The association between UPI and statin adherence was independent of socio-demographic and health-related factors. Stratification analyses further showed a stronger association among those who were new to statins (RR 1.33, 95% CI 1.15–1.54).

Conclusions

Greater continuity of care has a positive association with medication adherence for statins which is independent of socio-demographic and health-related factors.

Evaluation of software maintain ability with open EHR - a comparison of architectures

PURPOSE

To assess whether it is easier to maintain a clinical information system developed using open EHR model driven development versus mainstream methods.

METHODS

A new open source application (GastrOS) has been developed following open EHR's multi-level modelling approach using .Net/C# based on the same requirements of an existing clinically used application developed using Microsoft Visual Basic and Access database. Almost all the domain knowledge was embedded into the software code and data model in the latter. The same domain knowledge has been expressed as a set of open EHR Archetypes in GastrOS. We then introduced eight real-world change requests that had accumulated during live clinical usage, and implemented these in both systems while measuring time for various development tasks and change in software size for each change request.

RESULTS

Overall it took half the time to implement changes in GastrOS. However it was the more difficult application to modify for one change request, suggesting the nature of change is also important. It was not possible to implement changes by modelling only. Comparison of relative measures of time and software size change within each application highlights how architectural differences affected maintain ability across change requests.

CONCLUSIONS

The use of open EHR model driven development can result in better software maintain ability. The degree to which open EHR affects software maintain ability depends on the extent and nature of domain knowledge involved in changes. Although we used relative measures for time and software size, confounding factors could not be totally excluded as a controlled study design was not feasible.

Factors influencing adherence in long-term use of statins

PURPOSE

To assess the factors influencing adherence in long-term medication use as exemplified by statins.

METHODS

Data from an in-depth survey of Australians aged 45 years and over were linked to national prescription reimbursement data to assess medication possession ratio (MPR) for statins for the middle two years of a four-year period of statin possession. Poisson regression was used to calculate the relative risk (RR) for adherence (MPR ≥ 80%) for patient characteristics and factors related to access to and need for health care services. Separate models were fit for patients receiving healthcare concession subsidies and those who do not ('general beneficiaries').

RESULTS

In the analysis, 42 492 concessional and 16 110 general beneficiary patients were included, with 80.1% and 56.7% showing MPR ≥ 80%, respectively. In both models, RR for adherence was significantly elevated for older (age 65+) and less healthy (worse self-rated health, pre-existing heart condition or obese) individuals, and for those who had private health insurance. Significantly lower RR (i.e. more non-adherence) was found for individuals reporting speaking a language other than English at home, who were smokers, were employed, and had higher levels of education, and for those who reported psychological distress. Income had no significant relationship with adherence, and the pattern of adherence by remoteness of area of residence was inconsistent.

CONCLUSIONS

Poor adherence in long-term use of statins is commonplace, but a number of key predictors-including age, language other than English spoken at home, smoking status and psychological distress-are readily assessable by the prescribing practice.

Emergency department triaging of admitted stroke patients--a Bayesian Network analysis

This study uses hospital administrative data to ascertain the differences in the patient characteristics, process and outcomes of care between the Emergency Department (ED) triage categories of patients admitted from an ED presentation into a large metropolitan teaching hospital with a Stroke Care Unit. Bayesian Networks (BNs) derived from the administrative data were used to provide the descriptive models. Nearly half the patients in each stroke subtype were triaged as 'Urgent' (to be seen within 30 minutes). With a decrease in the urgency of triage categories, the proportion admitted within 8 hours decreased dramatically and the proportion of formal discharge increased. Notably, 45% of transient ischaemic attacks (TIAs) were categorized as 'Semi-urgent' (to be attended within 60 minutes), indicating an opportunity to improve emergency assessment of TIAs. The results illustrate the utility of hospital administrative data and the applicability of BNs for review of the current triage practices and subsequent impact.

Formal-Transfer In and Out of Stroke Care Units

The positive impact of stroke care units (SCUs) on patient outcome has been previously reported. In this study, long-term stroke patients that are formally admitted to teaching-hospitals are compared with and without SCUs. The authors focus on the patients’ experience with ongoing care or formal transfers following current care as this cohort is often high users of the system with associated high costs. Bayesian Networks were employed to analyze routinely collected public-hospital administrative data. The results illustrate that the teaching-hospitals with SCUs, while achieving shorter length of stay, in fact deal with younger patients with lower overall patient complexity than non-SCU teaching-hospitals. Other differences include SCUs predominantly treating subarachnoid hemorrhages whereas the non-SCUs treat more cerebral infarctions. This study illustrates the power of Bayesian Networks to expose the nature of caseload and outcomes recorded in hospital-administrative data as a means to gain insight on current practice and create opportunities for benchmarking and improving care.

Developing high-specificity anti-hypertensive alerts by therapeutic state analysis of electronic prescribing records

OBJECTIVE

This paper presents a model for analysis of chronic disease prescribing action over time in terms of transitions in status of therapy as indicated in electronic prescribing records. The quality of alerts derived from these therapeutic state transitions is assessed in the context of antihypertensive prescribing.

DESIGN

A set of alert criteria is developed based on analysis of state-transition in past antihypertensive prescribing of a rural Australian General Practice. Thirty active patients coded as hypertensive with alerts on six months of previously un-reviewed prescribing, and 30 hypertensive patients without alerts, are randomly sampled and independently reviewed by the practice's two main general practice physicians (GPs), each GP reviewing 20 alert and 20 non-alert cases (providing 10 alert and 10 non-alert cases for agreement assessment).

MEASUREMENTS

GPs provide blind assessment of quality of hypertension management and retrospective assessment of alert relevance.

RESULTS

Alerts were found on 66 of 611 cases with coded hypertension with 37 alerts on the 30 sampled alert cases. GPs assessed alerting sensitivity as 74% (CI 52% - 89%) and specificity as 61% (CI 45% - 74%) for the sample, which is estimated as 26% sensitivity and 93% specificity for the antihypertensive population. Agreement between the GPs on assessment of alert relevance was fair (kappa = 0.37).

CONCLUSIONS

Data-driven development of alerts from electronic prescribing records using analysis of therapeutic state transition shows promise for derivation of high-specificity alerts to improve the quality of chronic disease management activities.

Evaluation of the Vitek 2 system for rapid identification of clinical isolates of gram-negative bacilli and members of the family Streptococcaceae

Accuracy of the Vitek 2 automated system (bioMérieux Vitek, USA) for rapid identification of bacteria was evaluated using a collection of 858 epidemiologically unrelated gram-negative and 99 gram-positive clinical isolates. Isolates were tested after subculturing to ensure purity. Conventional agar-based biochemical tests (Steers replicator) were used as a reference method of identification. Gram-negative bacteria were identified to the species level with 95.3% accuracy by the system ( Enterobacteriaceae, 95.9%; and non- Enterobacteriaceae, 92.5%), and gram-positive isolates with 72% accuracy. Although Vitek 2 identified routine clinical isolates of gram-negative bacilli and Enterococcus faecalis and Enterococcus faecium reliably, rapidly, and reproducibly, improvement is required in the identification of less common species of enterococci and viridans group streptococci.

Automated attention flags in chronic disease care planning

OBJECTIVES

To assess the value of computerised decision support in the management of chronic respiratory disease by comparing agreement between three respiratory specialists, general practitioners (care coordinators), and decision support software.

METHODS

Care guidelines for two chronic obstructive pulmonary disease projects of the SA HealthPlus Coordinated Care Trial were formulated. Decision support software, Care Plan On-Line (CPOL), was created to represent the intent of these guidelines via automated attention flags to appear in patients' electronic medical records. For a random sample of 20 patients with care plans, decisions about the use of nine additional services (eg, smoking cessation, pneumococcal vaccination) were compared between the respiratory specialists, the patients' GPs and the CPOL attention flags.

RESULTS

Agreement among the specialists was at the lower end of moderate (intraclass correlation coefficient [ICC], 0.48; 95% CI, 0.39-0.56), with a 20% rate of contradictory decisions. Agreement with recommendations of specialists was moderate to poor for GPs (kappa, 0.49; 95% CI, 0.33-0.66) and moderate to good for CPOL (kappa, 0.72; 95% CI, 0.55-0.90). CPOL agreement with GPs was moderate to poor (kappa, 0.41; 95% CI, 0.24-0.58). GPs were less likely than specialists or CPOL to decide in favour of an additional service (P<0.001). CPOL was 87% accurate as an indicator of specialist decisions. It gave a 16% false-positive rate according to specialist decisions, and flagged 61% of decisions where GPs said No and specialists said Yes.

CONCLUSIONS

Automated decision support may provide GPs with improved access to the intent of guidelines; however, further investigation is required.

Outbreak of nosocomial infections due to extended-spectrum beta-lactamase-producing strains of enteric group 137, a new member of the family Enterobacteriaceae closely related to Citrobacter farmeri and Citrobacter amalonaticus

A member of the Enterobacteriaceae initially identified as Kluyvera cryocrescens by the MicroScan Gram-Negative Combo 13 panel caused an outbreak of nosocomial infections in four patients (pneumonia, n = 2; urinary tract infection, n = 1; wound infection, n = 1) and urinary tract colonization in one patient. When the strains were tested by the Enteric Reference Laboratory of the Centers for Disease Control and Prevention, biochemical results were most compatible with Yersinia intermedia, Kluyvera cryocrescens, and Citrobacter farmeri but identification scores were low and test results were discrepant. However, when the biochemical test profile was placed in the computer database as a new organism, all strains were identified as the organism with high identification scores (0. 999968 to 0.999997) and no discrepant test results. By 16S rRNA sequence analysis the organism clustered most closely with, but was distinct from, Citrobacter farmeri and Citrobacter amalonaticus. Based on its unique biochemical profile and rRNA sequence, this organism is designated Enteric Group 137. Restriction endonuclease analysis and taxonomic antibiograms of strains causing the outbreak demonstrated a single clone of Enteric Group 137, and antibiotic susceptibility testing revealed the presence of extended-spectrum beta-lactamase (ESBL) resistance. Enteric Group 137 appears to be a new opportunistic pathogen that can serve as a source of ESBL resistance in the hospital.

Gastric pathology associated with Helicobacter pylori

A bacterium is associated with a specific gastritis. Neutrophils infiltrate the necks of the glands, just deep to the infected foveolae. This infiltration rarely, if ever, occurs without H. pylori infection. Foveolar epithelial damage is common, with loss of cell structure. Electron microscopy suggests that the bacteria cause this damage as they attach to the superficial cell membrane. These features, defined by Whitehead et al as active changes, appear specific for H. pylori infection. The neutrophils and specific epithelial changes disappear within days of starting treatment for Helicobacter. They rapidly recur if the treatment is unsuccessful. Without treatment, the changes remain for decades and are severe in 10% to 20% of cases. Other changes occur in the mucosa. Reduced mucus secretion occurs in damaged or proliferating epithelium. This reduced secretion occurs near healing ulcers or with other types of inflammation but is often severe when Helicobacter is present. It returns to normal within weeks of treating the infection. The bacteria adhering to the cell membrane may cause this change directly. Lymphoid infiltration occurs with any type of chronic inflammation or immune reaction. The infiltration is not specific for Helicobacter, and it reduces slowly in months or years after eradication of H. pylori. Peptic ulceration, particularly duodenal ulceration, although not specific, is particularly common with H. pylori infection. The long-term inflammation probably causes other gastric pathology. Atrophy is common. Epithelial metaplasia occurs in about 20% of patients, usually mild. Other features, such as scarring, epithelial dysplasia, and in situ malignant change, are less common. They show little improvement after eradicating H. pylori. The part played by the bacteria in their cause remains uncertain. Pathologists see a long-standing chronic gastritis clearly related to a bacterium. The inflammation often is severe and commonly damages the mucosa, with ulceration, atrophy, metaplasia, and occasional premalignant changes. Physicians would treat inflammation of this degree in most other parts of the body. This disease is usually symptomless. There is some controversy, but eradicating Helicobacter often fails to improve nonulcer dyspepsia. This failure results in a continuing argument over whether or not to treat the infection. Meanwhile the pathology continues. A temporary solution to the problem is suggested: Patients infected with Helicobacter can give informed consent. Patients can be told about the infection, the pathology, the poor relationship to symptoms, and side effects of therapy, and they can decide.

Statistical modelling of general practice medicine for computer assisted data entry in electronic medical record systems

Electronic medical record (EMR) systems have much potential, however, there are still a number of issues that need to be resolved before EMRs are widely accepted. One of these issues is the data input task, a potentially serious practical barrier to on-line medical computer usage. This paper reports the empirical modelling of data input requirements for physicians who use a problem-orientated medical record system. Three statistical models (Bayesian conditional probability, multiple linear regression and discriminant analysis) to predict drug treatment given problem diagnoses are derived from EMRs of 2500 general Practice encounters. Two metrics are used to measure the predictive power of the models considering both the number of drugs correctly predicted and the strength with which the models predict them. The models are tested on 500 unseen records from the same patient-physician population and the data used to build the models. The Bayesian model produces the best predictions on unseen data and is also the easiest model to compute. A prototype interface that enables new patient cases to be entered is constructed to demonstrate how the predictive power of the model can translate into benefits in the data entry task.

Persistent tuberculosis or specimen contamination?

Cross-contamination during sequential processing of sputum specimens from different patients causes false-positive growth of Mycobacterium tuberculosis in culture. We describe an unusual case of cross-contamination in a 36-year-old man with acquired immunodeficiency syndrome and possible persistent tuberculosis. Culture with 1 of 3 sputum specimens was positive for rifampin-susceptible M tuberculosis. Review of processing revealed that his single culture-positive sputum specimen had followed a sputum specimen from another patient with active pulmonary tuberculosis that was positive in culture for M tuberculosis resistant to rifampin. Molecular strain typing by restriction fragment length polymorphism demonstrated the 2 isolates to be an identical strain of M tuberculosis. Agar proportion susceptibility testing of the rifampin-resistant isolate revealed low numbers of resistant organisms in a range of 1.5% to 3.3%. It was concluded that rifampin-susceptible organisms that constituted approximately 98% of the resistant isolate contaminated sputum from the patient with possible persistent tuberculosis. His culture result was, therefore, considered false positive, not an indication of tuberculosis.

A minimum 5.0 ml of sputum improves the sensitivity of acid-fast smear for Mycobacterium tuberculosis

Detection of acid-fast bacilli (AFB) by sputum smear supports treatment decisions with pulmonary tuberculosis (TB), but smear sensitivity for Mycobacterium tuberculosis is only approximately 45 to 75%. In an effort to increase sensitivity, smears were prepared using a minimum sputum volume of 5.0 ml. Sensitivity of smears during a 39-mo period (n = 1,849) using >/= 5.0 ml of sputum was 92. 0%, significantly greater (p < 0.001) than a sensitivity of 72.5% in a previous 24-mo period (n = 3,486) when all specimens were processed regardless of volume. All new cases of TB (n = 18) were smear-positive with >/= 5.0 ml of sputum before treatment, and all were receiving antituberculosis drugs at hospital discharge. In contrast, significantly fewer new cases of TB (14 of 26, p = 0.002) were positive before treatment when smears were prepared using sputum of any volume, and significantly fewer of these new TB cases (18 of 26, p = 0.03) were receiving treatment at hospital discharge. The eight cases without treatment were smear-negative. These results indicate that acid-fast smear using >/= 5.0 ml of sputum increases sensitivity for M. tuberculosis and accelerates treatment of TB.

In vitro activity of RP 59500 (quinupristin/dalfopristin) and ramoplanin against vancomycin-resistant Enterococcus faecium

Vancomycin-resistant Enterococcus faecium (VREF) collected between July 1991 and February 1994 were tested in vitro against RP 59500 and ramoplanin using agar dilution and standard macro broth dilution procedures. Colony counts were determined at 0, 4, and 24 h. RP 59500 had an MIC range of < or = 0.5-8 micrograms/ml with an MIC90 of 2 micrograms/ml and a MBC range of < or = 0.5-16 micrograms/ml with an MBC90 of 16 micrograms/ml. Ramoplanin had an MIC range of < or = 0.125-1 microgram/ml with an MBC range of < or = 0.125-4 micrograms/ml. The MIC90 for ramoplanin was 1 microgram/ml and the MBC90 was 4 micrograms/ml for the tested isolates. Against these isolates of E. faecium, RP 59500 was bactericidal at 8x MIC, a potentially achievable level using a high drug dosage. Ramoplanin was bactericidal at 2x MIC.

Chronic disease coordinated care planning: flexible, task-centered decision support

SA HealthPlus is a trial of coordinated care enrolling 4000 high-use patients in South Australia in 10 groups including diabetes, cardiac, aged care and lung disease. These patients each have a designated general practitioner (GP) care coordinator who formulates an individualized care plan designed to keep them as healthy as possible. An on-line interface to SA HealthPlus has been developed for the care coordinators. The Care Plan On-Line (CPOL) system provides a single coherent source whereby the GP can review the available information on a HealthPlus patient in the context of devising a care plan of prospective services and medications. In the same application environment CPOL provides access to care guidelines tailored for SA HealthPlus.

Can computer autoacquisition of medical information meet the needs of the future? A feasibility study in direct computation of the fine grained electronic medical record

The project describes feasibility testing of a two-year clinical deployment of an electronic record keeping system for primary care medicine that allowed financial medical management and clinical disease study without the encumbrance of human encoding. The software used an expert system for acquisition of historical information and automatic database encoding of each independent fact. The historical acquisition system was combined with a screen-based physician data entry system to create a fine-grained medical record. Fine-grained data allowed direct computer processing to mimic the ends that presently require human encoding--gatekeeping, disease characterization and remote disease surveillance. The project demonstrated the possibility of real time gatekeeping through direct analysis of data. Detection and characterization of disease states using statistical methods within the database was possible, however, limited in this study because of the large numbers of patient interviews required. The possibilities for remote disease monitoring and clinical studies are also discussed.

Intelligent split menus for data entry: a simulation study in general practice medicine

A compelling notion in menu design is that a few of the most frequently selected items should be placed as a hot list at the top of the menu. A few researchers have explored this type of interface control, known as a split menu, and have investigated the identification of the hot-list items by statistical analysis of past data. We extend the technique to automated development of dynamic hot-lists for entry of medication data in a General Practice setting. Using clinical data from 113,000 visits, a statistical model is developed and evaluated by simulated data entry of cases held back from training. Simulated SOAP note entry shows 12-item hot lists to hold over 70% of desired drug and diagnosis selections. Intelligent split menus should improve user efficiency if current selection methods require 3 seconds or more per item. A demonstration prototype can be downloaded over the Web.

Detecting disseminated Mycobacterium avium complex infections in HIV-positive patients. The usefulness of bone marrow trephine biopsy specimens, aspirate cultures, and blood cultures

Disseminated Mycobacterium avium complex (MAC) infections are common in patients with acquired immunodeficiency syndrome (AIDS). These patients frequently seek care with fever accompanied by generalized systemic symptoms and undergo bone marrow biopsy. It is our practice to stain all bone marrow trephine biopsy specimens from patients infected with HIV for acid-fast bacilli (AFB). We evaluated this practice by comparing the sensitivity and turnaround time for detection of MAC by biopsy specimen staining, bone marrow aspirate culture, and blood culture. Bone marrow trephine biopsy specimens with corresponding bone marrow aspirate and blood cultures from 86 HIV-positive patients were reviewed. Of the 86 patients, 30 had positive results for disseminated MAC infection, and all 30 of those patients had positive blood cultures. Bone marrow aspirate cultures identified 17 MAC-positive cases, and AFB staining of the biopsy specimen identified 9. The mean times to detection of MAC positivity were 1.1 days for AFB staining of the biopsy specimen, 19 days for bone marrow aspirate culture, and 16 days for blood culture. While AFB staining of biopsy specimens was the least sensitive of the detection methods, it was useful for the rapid diagnosis of disseminated MAC infection, allowing for prompt initiation of antimycobacterial therapy in one third of patients.

Induction of a variety of preneoplasias and tumours in the mammary glands of transgenic rats

Although transgenic mouse models for breast cancer have frequently been reported in the literature, transgenic rat models have not been described. We have generated transgenic rats overexpressing the human transforming growth factor alpha (TGF alpha) and c-erbB-2 genes in the mammary gland under the control of the mouse mammary tumour virus (MMTV) long terminal repeat promoter, and have analysed multiple lines of these rats to the second (F2) generation. Female MMTV/TGF alpha rats frequently develop severe hyperplasias during pregnancy, and a variety of tumours of long latency. The mammary glands of MMTV/TGF alpha rats fail to involute fully after the completion of lactation. Expression of the TGF alpha transgene is highest in the hyperplasias. MMTV/c-erbB-2 female rats develop a spectrum of benign and malignant lesions, including ductal carcinoma in situ and carcinomas. Expression of the c-erbB-2 transgene is found in benign tumours such as fibroadenomas, but is highest in the carcinomas. These animals model a spectrum of lesions found in human breasts and suggest that TGF alpha overexpression can act at a relatively early stage in the pathogenesis of breast cancer in the rat, resulting in a predominantly hyperplastic response, whereas overexpression of c-erbB-2 plays a role in the induction of various benign lesions and more advanced breast carcinomas.

Cross-contamination of specimens with Mycobacterium tuberculosis: clinical significance, causes, and prevention

At the Veterans Affairs Lakeside Medical Center, two episodes of specimen cross-contamination with Mycobacterium tuberculosis were detected during a 54-month period by molecular strain typing using DNA restriction fragment length polymorphism for 3 patients without clinical or radiologic signs of tuberculosis (TB). A cross-contaminated specimen was the only culture-positive specimen for each of the 3 patients. Laboratory features of cross-contamination included acid-fast smear negativity, growth only in broth or solid medium, and growth in solid medium with 5 or fewer colonies. Retrospective analysis demonstrated identical features for occasional culture-positive specimens from 54 patients with TB during the same period. However, productive cough, pleural pain, weight loss, night sweats, chest radiograph results suggestive of TB, positive tuberculin skin testing, and/or multiple culture-positive specimens were invariably present in patients with TB with such specimens. Most patients with TB (50/54; 93%) had multiple specimens positive in culture for M. tuberculosis, and the few patients with TB with single culture-positive specimens were symptomatic. These results indicate that correlation with clinical manifestations is necessary to determine the significance of isolated, acid-fast smear negative, and/or low-yield culture-positive specimens. Although the prevalence of specimen cross-contamination is low (0.1%), possible sources (especially the use of single-reagent delivery systems for multiple specimens) should be eliminated by mycobacteriology laboratories.

Webifying a patient interview support application

This paper reports on the software engineering challenges, and resultant benefits experienced, in porting an interactive, knowledge-based system from Microsoft Windows to the World Wide Web for evaluation purposes. The Patients Interview Support Application (PISA) is a program intended for operation by a non-expert clerk to interview an ambulatory primary care patient. The PISA code had to be re-written substantially to address the 'connectionless' nature of Web dialog and to work in terms of dynamically generated HTML forms; however, it was possible to avoid any revision of the central knowledge-base or inference engine. The resultant Web environment attracted thought-provoking and detailed feedback from users, indicating that significant attention can be obtained from the global community by mounting an interactive system on the Web. Specific enhancements to the PISA's artificial intelligence are suggested by user reaction. A future global health informatics 'marketplace' with a multidue of Web-based system components available for composition of health information systems is envisioned.

Cerebrospinal fluid broth culture isolates: their significance for antibiotic treatment

Enriched broth medium is routinely used as a supplement for agar plate culture of cerebrospinal fluid (CSF). To assess the clinical utility of broth cultures, 151 consecutive CSF bacterial and fungal isolates obtained from 91 patients were retrospectively reviewed for the effect of results on treatment. Treatment decisions associated with individual CSF specimens for which isolates were recovered from thioglycollate broth only were compared with the treatment decisions associated with CSF specimens for which isolates were recovered by agar plate culture. Treatment was defined as initiation of or change in antimicrobial therapy based on the reporting of CSF culture isolates. Thirty-six (24%) of the 151 isolates were recovered in broth only. Three (8%) of these 36 isolates (from 34 patients) resulted in treatment with antimicrobial agents; however, 2 of the 3 treated isolates (Candida tropicalis, Proteus mirabilis) were recovered from a second CSF specimen in agar plate culture within 24 hours. Thus, only a single isolate (3%; Staphylococcus epidermidis) was treated based solely on a positive broth culture result. In contrast, 60 (52%) of the 115 isolates recovered in agar plate culture from 23 (40%) of 57 patients were treated (staphylococci, 28; gram-negative bacilli, 14; Cryptococcus neoformans, 10; Streptococcus pneumoniae, 3; Streptococcus sanguis, 1; other, 4). We conclude that treatment with antimicrobial agents based on isolates recovered from CSF specimens in broth culture alone is infrequent and infer from the data that the use of CSF broth cultures contributes little to treatment decisions.

Plasmacytoma of the sigmoid colon associated with a diverticular stricture: case report and review of the literature

Plasmacytoma is a malignant tumour composed of plasma cells. Most commonly this takes the form of a plasma cell infiltration of bone marrow-multiple myeloma. This may be seen radiologically as either discrete lytic lesions or diffuse osteoporosis. Plasma cells are seen on bone marrow biopsy, and monoclonal immunoglobulins may occur in plasma and/or urine. Less frequently, plasma cell tumours may present as a solitary myeloma of bone, which often progresses to multiple myeloma, or as a plasma cell leukemia. Primary plasma cell tumours in an extramedullary site are relatively rare. Such soft tissue plasmacytomas usually occur in the nasopharynx or conjectiva, and are seldom located in the lower gastrointestinal tract. We report a case of primary plasmacytoma associated with a diverticular stricture in the sigmoid colon, an occurrence not previously documented, and review the current literature.

Long-term follow-up of gastric histology after Helicobacter pylori eradication

Helicobacter pylori causes chronic active gastritis and is thought to be associated with the development of gastric atrophy, intestinal metaplasia and carcinoma. As the effect of H. pylori eradication on this process is poorly understood, we sought to determine the long-term effects of H. pylori eradication on gastric histology. Fifty-four patients with duodenal ulceration associated with H. pylori infection received H. pylori eradication therapy in 1985/86 and either remained infected (n = 22) or had the infection eradicated (n = 32); patients were followed up by endoscopy with gastric antral biopsy for 7.1 years (mean). Histopathological analysis of gastric antral mucosa from patients rendered H. pylori-negative revealed a marked decrease in both inflammatory cells within the lamina propria and intraepithelial neutrophils and an increase in epithelial mucinogenesis. Gland atrophy remained unchanged in both H. pylori-positive and -negative patients. When examined for the presence and severity of intestinal metaplasia, there was neither a difference between the two patient groups nor a change with time. These data demonstrate that significant long-term improvements in gastric histology accompany H. pylori eradication when compared with histology in patients with persistent infection. Whether this confers a protective effect by reducing the risk of gastric carcinoma remains unknown.

Enterococcus faecium and Enterococcus faecalis bacteremia: acquisition and outcome

The incidence of enterococcal bacteremia due to Enterococcus faecium is increasing. To understand the clinical significance of E. faecium bacteremia, we compared 16 patients who were bacteremic due to E. faecium to 56 patients who were bacteremic due to Enterococcus faecalis. E. faecium bacteremia developed most frequently in severely ill patients with fever or hypothermia accompanied by CNS, cardiovascular, and/or pulmonary dysfunction, while E. faecalis bacteremia occurred most often in less seriously ill patients. Nosocomial acquisition, cancer, neutropenia, renal insufficiency, current corticosteroid therapy, and previous treatment with broad-spectrum antibiotics were significantly more frequently associated with E. faecium bacteremia. Mortality was significantly higher among patients infected with E. faecium than among those infected with E. faecalis (50% vs. 11%; P = .001); this was true particularly among patients with monomicrobial or nosocomial bacteremia, those who had previously received antibiotic treatment, and those with cancer. Death due to enterococcal bacteremia was observed only among severely ill patients. These findings suggest that E. faecium often infects debilitated patients and that such infection appears to be a significant factor contributing to mortality.

Duodenal ulcer treated with Helicobacter pylori eradication: seven-year follow-up

The long-term benefits of Helicobacter pylori-eradication treatment (HET) in H pylori-associated duodenal ulcer are unclear. We followed up patients with duodenal ulcers from a trial of H pylori eradication in 1985-86. 63 of 78 patients (81%) were reviewed clinically and had upper gastrointestinal endoscopy with gastric antral biopsy. Of 35 patients previously rendered H pylori negative, 32 (92%) remained H pylori negative after 7.1 years (mean). All patients initially H pylori positive remained infected, unless HET was given in the interim. Duodenal ulceration was found in 20% (5 out of 25) of patients remaining H pylori-positive, compared with 3% (1 of 38) of H pylori-negative patients (p < 0.05). The reduction of duodenal ulcer relapse obtained from H pylori eradication in H pylori-associated duodenal ulcer extends to at least 7 years after treatment, and is likely to be due to freedom from H pylori infection. However, duodenal ulcer may recur in patients rendered H pylori negative, due to factors other than reinfection with H pylori.

When is Helicobacter pylori infection acquired?

Cross sectional surveys have shown an increasing prevalence of Helicobacter pylori (H pylori) infection with increasing age in Western populations. The aim of this study was to examine the pattern of acquisition of H pylori infection over a 21 year period in a group of 141 adults who had blood samples and serum stored in 1969, 1978, and 1990. A prevalence of H pylori antibody of 39% in 1969 serum samples, 40.9% in 1978, and 34.8% in 1990 was found when assessed by an enzyme linked immunosorbent assay (ELISA). Of the 86 subjects who were seronegative in 1969, only six (7%) were seropositive in 1990. These data suggest that a cohort effect may contribute to the pattern of increasing prevalence of H pylori infection seen with increasing age. Acquisition of infection in adults is rare. It is unlikely, therefore, that reinfection will occur after successful eradication.

Bactericidal activity of the fluoroquinolone WIN 57273 against high-level gentamicin-resistant Enterococcus faecalis

The fluoroquinolone WIN 57273 showed identical bactericidal activities (MBC for 90% of the strains = 0.25 micrograms/ml) for bacteremic strains of Enterococcus faecalis with and without high-level gentamicin resistance. WIN 57273 was bactericidal in time-kill measurements with highly gentamicin-resistant, ciprofloxacin-susceptible strains of E. faecalis. However, WIN 57273 was indifferent with penicillin for gentamicin-resistant E. faecalis and was not bactericidal for ciprofloxacin-resistant E. faecalis.

Inhibition of preimplantation mouse embryo development by isoflurane

OBJECTIVE

Preimplantation mouse embryos were exposed to a commonly used inhalational anesthetic agent, isoflurane, to determine its effects on embryo development.

STUDY DESIGN

Two-cell embryos were exposed at various intervals (5 to 6 hours, 3 to 4 hours, and 0 to 1 hour) before the onset of their first cleavage in vitro. In addition, the effects of 5% isoflurane on four-cell embryos exposed about 2 hours after the first cleavage and morula stage embryos also were examined.

RESULTS

Development to the blastocyst stage was inhibited by 3% and 5% isoflurane (p less than 0.005) but not by 1.5% isoflurane when two-cell embryos were exposed 3 to 4 hours or 0 to 1 hour before the onset of cleavage. Most of the affected embryos completed cell division and came to a halt at the three- to four-cell stage. The development of embryos exposed to isoflurane at the four-cell or morula stage was unaffected.

CONCLUSIONS

Isoflurane adversely affects subsequent preimplantation development when two-cell mouse embryos are exposed just before the onset of their first cleavage in vitro.

High-level gentamicin resistance in Enterococcus faecalis bacteremia

In a retrospective analysis, patients with bacteremia due to Enterococcus faecalis with and without high-level gentamicin resistance (GRE; MIC greater than 2000 micrograms/ml) were compared. Bacteremic patients with GRE (n = 32) had significantly higher rates of nosocomial acquisition and bladder catheterization, longer hospitalizations, and more frequent prior treatment with cephalosporins than did bacteremic patients without high-level resistance (n = 19). Overall mortality was significantly associated with septic shock, high-risk source (intraabdominal, wound, respiratory tract, multiple, unknown), and polymicrobial bacteremia. Higher mortality was observed in GRE bacteremia (47%) than in bacteremia without high-level resistance (37%), but this difference was not statistically significant. For patients with monomicrobial bacteremia, low-risk source (genitourinary tract, intravascular), or treatment with antibiotics appropriate for the enterococcus, higher mortality with GRE bacteremia approached statistical significance. These results suggest that high-level resistance adversely affects survival with a pure E. faecalis bacteremia or low-risk bacteremic source. Also, response to antibiotic therapy may be diminished by high-level resistance.

Effects of nitrous oxide on preimplantation mouse embryo cleavage and development

Preimplantation mouse embryos were exposed to nitrous oxide for 30 min to determine its effects on subsequent development after short durations of exposure. Two-cell mouse embryos were exposed to 60% nitrous oxide/40% oxygen at 6-7 h, 3-4 h, or 0-1 h prior to the expected onset of their first cleavage in vitro, or at the 4-cell or morula stages. Effects of nitrous oxide were not observed except in 2-cell embryos treated within 4 h of the expected in vitro cleavage. At 3-4 h and 0-1 h prior to the onset of cleavage, exposure to 60% nitrous oxide/40% oxygen resulted in blastocyst development rates of 27.7% and 4.7%, respectively, while control rates ranged from 75% to 77%. The majority of affected embryos were halted at the 2-cell stage before completing cell division. Similar effects were obtained with 80% nitrous oxide/20% oxygen. Thus, we conclude that brief exposure of mouse preimplantation embryos to nitrous oxide may be deleterious to subsequent embryo cleavage, but this effect is highly dependent on the developmental stage at which exposure occurs.

The 14C-urea breath-test for the detection of gastric Campylobacter pylori infection

A breath-test has been developed for the detection of gastric infection with Campylobacter pylori. Urea that is labelled with carbon 14 is administered to a fasting patient and the patient's breath is sampled for radioactivity over the following 30 minutes. If C. pylori is present in the patient's stomach, urease activity causes hydrolysis of the urea and the 14C is absorbed as carbon dioxide. This carbon dioxide enters the patient's bicarbonate pool and eventually is excreted in the breath. The results are expressed as a percentage of the administered dose/mmol carbon dioxide x kg body weight. Sixty-three patients who were undergoing endoscopy were studied. The radioactivity in exhaled breath which was sampled within five minutes of 14C-urea administration was attributed to the presence of urease enzyme in mouth organisms and was discounted. The time-radioactivity curves for breath samples from five to 30 minutes after the administration of 14C-urea gave an excellent separation between subjects with negative results of the examination of gastric-biopsy samples and patients with microbiological and histological evidence of infection with C. pylori. The area under the time-radioactivity curve at between five and 30 minutes after the administration of 14C-urea in 24 patients with negative microbiological results was 6.9 +/- 4.4 area units; in 35 of 39 patients with positive microbiological results, this area was greater than 40 area units. Measured against the results of the microbiological examination of gastric-biopsy samples, the sensitivity of breath-testing was 90% and the specificity was 100%. Measured against the results of histological examination for the presence of C. pylori infection, breath-testing had a sensitivity of 94% and a specificity of 93%. A positive breath-test result also correlated well (P = 0.0001) with the serological antibody test-result. The role of non-invasive tests--enzyme-linked immunosorbent assays and 14C-urea breath-testing--in the management of gastritis and peptic ulcer disease is discussed. We consider that the 14C-urea breath-test has an important role in the noninvasive confirmation of gastric infection with C. pylori and in the follow-up of patients after treatment.

Stimulation of epithelial hyperplasia in rat urinary bladder by Escherichia coli cystitis

Using heterotopically transplanted rat urinary bladder, experiments were conducted to develop a reproducible animal model of bacterial cystitis-associated urothelial hyperplasia without calculus formation, and to elucidate which bacterial component(s) might induce urothelial hyperplasia. Bladder instillation of live Escherichia coli (E. coli) resulted in persistent infection and inflammation and also diffuse urothelial hyperplasia. Instillation of killed E. coli also induced diffuse hyperplasia. Hyperplastic changes regressed following withdrawal of the killed E. coli treatment. Urothelial hyperplasia was also induced by repeated instillation of protein-rich lipopolysaccharide (LPS), the endotoxin derived from gram-negative bacterial wall component, but not by protein-free LPS. A finding common to bladders showing hyperplasia was the infiltration of neutrophils into intercellular spaces of the urothelium. We conclude that urothelial hyperplasia is induced by E. coli cystitis, that LPS plays a significant role in the hyperplastic response, and that neutrophils may mediate the response.

The pulmonary clearance of smooth and rough strains of Pseudomonas aeruginosa

Upper airway colonization with rough strains of Pseudomonas is associated with clinical deterioration in patients with cystic fibrosis. These rough strains are less toxic than smooth strains in the burned mouse model and in vitro assays. We measured the 4-h pulmonary clearance of 10(4) and 10(6) rough and smooth Pseudomonas after intrabronchial inoculation. After 10(4) Pseudomonas, rough strains were cleared more efficiently than smooth strains (89 +/- 13% versus 140 +/- 19% of the original inoculum, respectively, p less than 0.05). This was associated with more total bronchoalveolar lavage PMNs after inoculation with rough as compared with smooth Pseudomonas (1.60 +/- 0.38 x 10(5) versus 0.55 +/- 0.09 x 10(5), respectively, p less than 0.05). After inoculation with 10(6) Pseudomonas, rough were cleared less efficiently than smooth Pseudomonas (380 +/- 45% versus 134 +/- 12% of the original inoculum, respectively, p less than 0.05). There was no difference in the BAL PMNs of the animals inoculated with either bacterial strain at this inoculum (8.1 +/- 0.6 x 10(5) and 9.4 +/- 1.0 x 10(5) for the rough and smooth Pseudomonas, respectively). When PMN differences were abolished in C5-deficient mice, 10(4) rough were cleared less efficiently than smooth Pseudomonas. The relatively poor clearance of rough Pseudomonas could not be explained by in vitro differences in PMN killing or BAL toxicity or by intrinsic growth rates.

Prospective double-blind trial of duodenal ulcer relapse after eradication of Campylobacter pylori

100 consecutive patients with both duodenal ulcer and Campylobacter pylori infection were followed up to see whether eradication of C pylori affected ulcer healing or relapse. Patients were randomly assigned to 8 weeks of treatment with cimetidine or colloidal bismuth subcitrate (CBS), with tinidazole or placebo being given concurrently from days 1 to 10, inclusive. Endoscopy, biopsy, and culture were done at entry, in weeks 10, 22, 34, and 62, and whenever symptoms recurred. There was no maintenance therapy. C pylori persisted in all of the cimetidine-treated patients and in 95% of those treated with cimetidine/tinidazole, but was eradicated in 27% of the CBS/placebo group and 70% of the CBS/tinidazole group. When C pylori persisted, 61% of duodenal ulcers healed and 84% relapsed. When C pylori was cleared 92% of ulcers healed (p less than 0.001) and only 21% relapsed during the 12 month follow-up period (p less than 0.0001).

Free calcium and calmodulin levels in acinar carcinoma and normal acinar cells of rat pancreas

Exposure of acinar carcinoma cells and normal acinar cells of rat pancreas to the muscarinic agonist drug carbamylcholine stimulated 45Ca2+ outflux from 45Ca2+-labeled cells. More rapid outflux of 45Ca2+ was detected for carcinoma cells following muscarinic stimulation than for normal cells. Direct fluorometric measurement of cytosolic Ca2+ under basal (unstimulated) conditions in quin 2-loaded cells revealed significantly lower concentration of free Ca2+ in carcinoma cells (approximately 180 nM) than in normal cells (approximately 200 nM). Stimulation with 1 mM carbamylcholine increased the cytosolic Ca2+ concentration in carcinoma and normal cells to approximately 1900 nM, after which carcinoma cells removed cytosolic Ca2+ at a faster rate to a post-stimulation plateau concentration of approximately 140 nM, in comparison to normal cells which obtained a post-stimulation plateau concentration of approximately 300 nM. Essentially identical differences between carcinoma and normal cells were detected upon stimulation with the peptidergic agonist cholecystokinin octapeptide. Finally, carcinoma cells demonstrated approximately 3 times greater calmodulin concentration than normal acinar cells. Also, the calmodulin antagonist drug W7 (N-6-(aminohexyl)-5-chloro-1-naphthalene sulfonamide) inhibited the carbamylcholine-induced release of intracellular Ca2+ in acinar carcinoma cells. These results indicate that neoplastic pancreatic acinar cells have retained mechanisms of muscarinic- and peptidergic-stimulated intracellular Ca2+ release, and implicate calmodulin as a regulatory factor in secretagogue activation of intracellular Ca2+ release. We propose that the more rapid decline of intracellular Ca2+ concentration following muscarinic or peptidergic stimulation and the increased intracellular calmodulin concentration indicate calmodulin-mediated down-regulation of free cytosolic Ca2+ in acinar carcinoma cells to levels lower than those of normal cells.

Failure of the Bactec 460 radiometer to detect Cryptococcus neoformans fungemia in an AIDS patient

Cryptococcus neoformans fungemia occurred in a patient with the acquired immunodeficiency syndrome (AIDS). The BACTEC 460 radiometer failed to detect Cryptococcus neoformans in eight aerobic BACTEC 6B culture bottles inoculated with the patient's blood. The diagnosis of cryptococcemia was established by terminal (seven-day) subculturing of 6B broth to chocolate agar, which was positive for all eight radiometrically negative blood culture bottles. It appears that radiometric measurement is not optimal for the laboratory detection of cryptococcal fungemia.

Rapid urease test in the management of Campylobacter pyloridis-associated gastritis

Campylobacter pyloridis colonization of the stomach may be an etiological factor in gastritis and peptic ulceration. Campylobacter pyloridis produces large amounts of urease, and the presence of this enzyme in gastric mucosa usually indicates infection with the organism. In this paper we describe the use of a rapid urease test (CLOtest) to detect C. pyloridis infection in gastric mucosal biopsies. In 141 consecutive endoscopy cases, antral biopsies were taken for culture and histology, and an extra biopsy was inserted into the CLOtest gel. There were 79 patients infected with C. pyloridis, 78 of whom were detected by CLOtest: 75% were positive at 20 min, 92% at 3 h, and 98% at 24 h. There were no false positive results. Eighteen infected patients were rebiopsied after a course of amoxycillin and bismuth subcitrate. Active chronic gastritis resolved in eight of nine who were cleared of the organism, but histological gastritis was unchanged in nine patients who were still infected. CLOtest is a simple, sensitive, and highly specific test that enables the endoscopist to diagnose C. pyloridis infection in the endoscopy room. A negative test after antibiotic therapy correlates with clearance of the bacteria and healing of active gastritis.

Enzyme-linked immunosorbent assay for Campylobacter pyloridis: correlation with presence of C. pyloridis in the gastric mucosa

Antibody to Campylobacter pyloridis was measured by ELISA in the sera of 160 patients from whom gastric biopsy specimens were also obtained. The antigen was an acid-glycine extract of C. pyloridis, and titers ranged from 80 to 22,000 ELISA units (EU). Of 117 patients in whom C. pyloridis was detected microbiologically or histologically, 87 (74%) had a titer greater than or equal to 300 EU, and only one had a titer less than 150 EU. Of 43 patients in whom C. pyloridis was not detected, only two (5%) had a titer greater than 300 EU. Thus, for a titer of 300 EU the ELISA test had a specificity of 97% and a sensitivity of 81%. At 150 EU the specificity was 78%, and the sensitivity was 99%. Histological diagnosis of active chronic gastritis was associated with a high median ELISA titer (485 E), chronic gastritis with a much lower titer (150 EU), and normal histology with a titer of 110 EU. Discriminating use of this serological test could be of assistance to detect C. pyloridis in the gastric mucosa.

Muscarinic receptor coupling to intracellular calcium release in rat pancreatic acinar carcinoma

Analysis by sodium dodecyl sulfate-polyacrylamide gel electrophoresis of cholinergic receptor protein affinity labeled with the muscarinic antagonist [3H]propylbenzilylcholine mustard revealed a major polypeptide with molecular weight of 80,000-83,000 in both acinar carcinoma and normal acinar cells of rat pancreas. Muscarinic receptor protein is therefore conserved in pancreatic acinar carcinoma. A small but significant difference was detected in the affinity of carcinoma cell receptors (Kd approximately 0.6 nM) and normal cell receptors (Kd approximately 0.3 nM) for reversible binding of the muscarinic antagonist drug, N-methylscopolamine. In addition, carcinoma cell muscarinic receptors displayed homogeneous binding of the agonist drugs carbamylcholine (Kd approximately 31 microM) and oxotremorine (Kd approximately 4 microM), whereas normal cell receptors demonstrated heterogeneous binding, with a minor receptor population showing high affinity binding for carbamylcholine (Kd approximately 3 microM) and oxotremorine (Kd approximately 160 nM), and a major population showing low affinity binding for carbamylcholine (Kd approximately 110 microM) and oxotremorine (Kd approximately 18 microM). Both carcinoma and normal cells exhibited concentration-dependent carbamylcholine-stimulated increases in cytosolic free Ca2+, as measured by 45Ca2+ outflux assay and intracellular quin 2 fluorescence. However, carcinoma cells were observed to be more sensitive to Ca2+ mobilizing actions of submaximal carbamylcholine concentrations, demonstrating 50% maximal stimulation of intracellular Ca2+ release at a carbamylcholine concentration (approximately 0.4 microM) approximately one order of magnitude below that seen for normal cells. These results indicate altered muscarinic receptor coupling to intracellular Ca2+ release in acinar carcinoma cells, which manifests as a single activated receptor state for agonist binding, and increased sensitivity of Ca2+ release in response to muscarinic receptor stimulation.

Differentiation of muscarinic cholinergic receptors in acinar carcinoma of rat pancreas

Analysis of muscarinic cholinergic receptors in pancreatic acinar carcinoma of rat by measurement of N-[methyl-3H]scopolamine binding has revealed a single homogenous population of muscarinic receptors in the tumor. The plasmalemma density (approximately 25 receptors/micron 2 of cell membrane surface) and dissociation constant (approximately 0.4 nM) of muscarinic receptors in acinar carcinoma cells are identical to the density and affinity of muscarinic receptors in normal acinar cells of rat pancreas. Muscarinic receptors in the carcinoma are functionally linked to cholinergic stimulation of cellular Ca2+ release. An equivalent number of functional muscarinic receptors is present in poorly differentiated carcinoma cells which are deficient in zymogen granules and protein secretion, as compared to well-differentiated carcinoma cells which contain granules and secrete protein in response to cholinergic stimulation. These observations indicate that muscarinic cholinergic receptors are displayed in normal fashion on tumor membranes and are fully expressed in carcinoma cells regardless of their degree of secretory development. Expression of muscarinic cholinergic receptors is thus a stable phenotypic property of pancreatic acinar carcinoma cells. This suggests that muscarinic receptor maturation is an early event in the differentiation of pancreatic exocrine cells, preceding acquisition of secretory responsiveness to cholinergic stimulation.

Evaluation of cultural techniques for isolating Campylobacter pyloridis from endoscopic biopsies of gastric mucosa

One hundred and three gastroscopic biopsies from 80 patients were cultured for Campylobacter pyloridis and studied histologically. Active chronic gastritis, as shown by the presence of polymorphonuclear leucocytes, was diagnosed in 51 biopsies and C pyloridis was found in 47. Sixteen gastric biopsies showed normal histology (no inflammation); C pyloridis was detected in only one of these, and a second biopsy taken from this patient at the same time showed active gastritis. Biopsies could be kept at 4 degrees C for five hours without loss of viability of C pyloridis. An inoculum made by grinding the biopsy in a ground glass grinder consistently gave a much heavier growth of C pyloridis than one made by mincing the specimen. The campylobacter supplement ferrous sulphate, sodium metabisulphite, sodium pyruvate (FBP) (Oxoid) was inhibitory for some isolates; the inhibitory component was found to be sodium metabisulphite. Contaminants, but not C pyloridis, were inhibited by the incorporation of vancomycin 6 mg/l, nalidixic acid 20 mg/l, and amphotericin 2 mg/l, but higher concentrations inhibited C pyloridis. Undried plates kept in a plastic container at room temperature for up to two weeks were as satisfactory as freshly poured plates for the isolation of C pyloridis.