Realist analysis of whether emergency departments with primary care services generate 'provider-induced demand'

Background

It is not known whether emergency departments (EDs) with primary care services influence demand for non-urgent care (‘provider-induced demand’). We proposed that distinct primary care services in EDs encourages primary care demand, whereas primary care integrated within EDs may be less likely to cause additional demand. We aimed to explore this and explain contexts (C), mechanisms (M) and outcomes (O) influencing demand.

Methods

We used realist evaluation methodology and observed ED service delivery. Twenty-four patients and 106 staff members (including Clinical Directors and General Practitioners) were interviewed at 13 EDs in England and Wales (240 hours of observations across 30 days). Field notes from observations and interviews were analysed by creating ‘CMO’ configurations to develop and refine theories relating to drivers of demand.

Results

EDs with distinct primary care services were perceived to attract demand for primary care because services were visible, known or enabled direct access to health care services. Other influencing factors included patients’ experiences of accessing primary care, community care capacity, service design and population characteristics.

Conclusions

Patient, local-system and wider-system factors can contribute to additional demand at EDs that include primary care services. Our findings can inform service providers and policymakers in developing strategies to limit the effect of potential influences on additional demand when demand exceeds capacity.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12873-022-00709-2.

Clinic screening for adverse childhood experiences in people living with HIV to Improve Care Delivery

Adverse childhood experiences (ACEs) are associated with negative health outcomes; however, screening for ACEs is not routinely performed among people living with HIV (PLWH). We conducted a single-center, cross-sectional pilot study to define the (1) prevalence of ACEs in PLWH and (2) acceptability of ACEs screening in routine out-patient clinical care. One hundred participants completed screening: median age of participants was 49 years (interquartile range: 38.5-59.5), 73% male, 66% Non-Hispanic Black/African American, and 47% gay/lesbian. Clinically significant ACEs score, defined as ≥4, was reported in 51%. High ACEs score was more common among participants <50 years old (64.7% vs. 36.7%; p < 0.01), but the prevalence of ACEs ≥4 did not differ by gender, race, ethnicity, or sexual orientation. Among participants with ≥4 ACEs, 44.4% screened negative on both PHQ-9 and PC-PTSD screens. The majority of participants (89%) reported a positive experience with ACEs screening. The prevalence of clinically significant ACEs in this clinic population of PLWH was more than twice that reported in the general population. Routine ACEs screening can improve delivery of trauma-informed care in the HIV primary care setting.

670 FACTORS ASSOCIATED WITH MORTALITY IN MULTI-ETHNIC HOSPITALISED COVID PATIENTS

Introduction

Whilst most patients during the COVID pandemic made an uneventful recovery, there was a significant minority in whom the disease was severe and unfortunately fatal. This survey aims to evaluate independent risk factors for those who died of COVID compared to survivors and to identify any markers for improvement in future management.

Methods

Medical records of all COVID patients admitted to two multi-ethnic, inner city acute district general hospitals over a 6-week period in 2020 were examined. Data collected included demographic details, medical comorbidities, and type of ward where they received care. Multivariable analysis using stepwise backward logistic regression was conducted to examine independent risk factors for those who died from COVID compared to survivors.

Results

Of 951 patients admitted with COVID, 284 died[30%]. Compared to survivors(n = 667), univariate analyses revealed COVID deaths were associated with increasing age[mean(CI): 79.3(77.9–80.7)vs64.7(63.4–66.0);P &lt; 0.001], Black African [16.2%vs11.7%;p &lt; 0.001] & South-Asian [12%vs9.1%;p &lt; 0.001] ethnicity, Hypertension [64.4%vs49.5%;p &lt; 0.001], Chronic Heart Disease(CHD)[40.1%vs20.7%;p &lt; 0.001], Chronic Respiratory Disease [17.6%vs12.0%;p = 0.02] Chronic Kidney Disease [18%vs11.1%;p = 0.004], Chronic Neurological Disease 43.3%vs23.7%;p &lt; 0.001]. Gender, Diabetes, asthma, obesity, Chronic Liver Disease and immunosuppression (disease or treatment related) were not associated with increasing mortality. Death rates between those in general wards vs intensive care were comparable[4.7%vs2.5%;p = 0.1]. Multivariable analyses showed age 60–70 [OR 2.3], age &gt; 70 [OR 6.5], Black Caribbean [OR 1.6], and CHD [1.5] were independent risk factors for COVID deaths.

Discussion

This large multi-ethnic study showed that age &gt; 60, Black Caribbean, and chronic heart disease were independent risk factors for COVID deaths. This study provides valuable information on independent prognostic implications for COVID, which can be used in future interventional studies aiming to improve COVID outcomes or in audits of clinical practice.

Abstract 1011: Disulfiram superior to ALDH1A1 inhibitor analogs in targeting ovarian cancer stem cells

Epithelial ovarian cancer (EOC) is a global health burden and remains the fifth leading cause of cancer related death in women worldwide with the poorest five-year survival rate of the gynecological malignancies. Disease recurrence is the major cause of morbidity and mortality of EOC, considered to be driven by the survival of chemoresistant, stem-like tumor-initiating cells (TICs). TIC populations in EOC can be identified by the expression of molecular markers such as aldehyde dehydrogenase (ALDH), CD133, Nanog and Sox2. Although the TICs have been characterized, little progress has been made in finding drugs to specifically target this population, which has driven the research and development of novel therapies to prevent relapse. We previously showed that disulfiram, an ALDH inhibitor, effectively targeted TICs in terms of viability, spheroid formation, oxidative stress and also prevented relapse in an in vivo model of EOC. In this study we sought to determine whether specific targeting of ALDH isoenzyme ALDH1A1 would provide similar benefit as the broader pathway inhibition by disulfiram. NCTs 505 and 506 are isoenzyme specific ALDH1A1 inhibitors whose activity was compared to the effects of disulfiram. Following treatment with either the NCTs or disulfiram, the viability of TICs versus adherent cells, sphere formation, oxidative stress and cell death in our in vitro relapse model were measured and compared in OC cell lines. We found that disulfiram decreased the viability of TICs significantly more effectively versus non-TIC cells, while no trend was observed when the cells were treated with the NCTs. Disulfiram also induced greater amounts of ROS than the NCTs and affected the expression of proteins associated with the NFkB and JNK signaling pathways. Comparison of disulfiram to the direct targeting of ALDH1A1 with the NCTs suggests that disulfiram's broader cellular effects are more suitable as a therapeutic to eradicate TICs from tumors and prevent OC relapse. In addition to providing insight into a fitting treatment for TICs, the comparison of disulfiram to NCTs 505 and 506 has increased our understanding of disulfiram's mechanism of action. Further elucidation of disulfiram's mechanism has the potential to reveal additional targets to treat OC TICs and prevent disease recurrence.

Citation Format: Michael Caminear, Brittney Harrington, Christina Annunziata. Disulfiram superior to ALDH1A1 inhibitor analogs in targeting ovarian cancer stem cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1011.

54 Patient Satisfaction During A Pandemic – Virtually Impossible?

Introduction

Throughout the COVID-19 pandemic we conducted virtual urology clinics for the first time at our institution. We aimed to assess patient satisfaction with the virtual clinic format.

Method

Patients who underwent virtual consultation were contacted by phone and surveyed about their appointment. Convenience, thoroughness, satisfaction, preference and reason for appointment were assessed via questionnaire

Results

77 randomly selected patients were contacted. 63 males (82%), 14 females (18%). Median age 61 years (range 16–86). 62 (80%) reviews, 12 (16%) new referrals, and 3 (4%) post-operative patients were surveyed. 55 (71%) were booked for repeat appointment, 13 (17%) for further investigations, 6 (8%) discharged, and 3 (4%) listed for surgery.

73 (95%) found it convenient, 3 (4%) were neutral and 1 (1%) found it inconvenient. 74 (96%) felt thoroughly assessed and 76 (99%) of patients had all their concerns addressed. 74 (96%) were satisfied with their review, 2 (3%) were neutral, and 1 (1%) was dissatisfied. Going forward, 50 (65%) would prefer virtual follow-up and 27 (35%) would prefer an in-person review.

Conclusions

Virtual clinic is preferable to the majority of patients in our urology service and is deemed convenient, thorough and satisfactory by them. It should be facilitated going forward in appropriately selected patients.

1268. Clinic Screening for Adverse Childhood Experiences among Persons with HIV: A Pilot Project

Background

Childhood trauma has long-lasting implications for adult health as prior work in the general population linked ≥4 adverse childhood experiences (ACEs) to multiple negative health outcomes in adulthood. History of childhood trauma is prevalent in people living with HIV (PLWH); however, screening for history of childhood trauma is not routinely performed in HIV clinical care.

Methods

We conducted a single-center, cross-sectional quality improvement pilot project to (1) define the prevalence of ACEs in PLWH engaged in care and (2) improve linkage with mental health resources. We hypothesized the prevalence of ≥4 ACEs in PLWH would be >21%, the prevalence previously reported in the local, general population. Patients were approached in the course of routine clinical care at an urban, academic HIV outpatient clinic between October 2018 and April 2019 and offered screening for ACEs, depression, and post-traumatic stress disorder (PTSD) using previously validated tools.

Results

Forty-nine patients completed the screening. Median age was 48 years [IQR: 37–55]; 69% were male and 53% were gay or bisexual. Most patients identified as black/African American (75%) and white (12%). Median ACEs score was 4 [IQR 1–6], with 51% (95% CI: 36–66%) reporting ≥4 ACEs (Figure 1), and most common ACE being guardian substance abuse (57%) (Figure 2). When compared with men, women had a higher median ACEs score (5 vs. 3, P = 0.04), history of childhood sexual abuse (67% vs. 26%, P <0.001), parent incarceration (53% vs. 24%, P = 0.04), and parental divorce or separation (73% vs. 41%, P = 0.04). Patients with ≥4 ACEs were more likely to have positive PTSD screens (56% vs. 21%, P = 0.02), moderate depression or greater (37% vs. 11%, P = 0.002), and were more likely to accept on-site mental health referral after screening (36% vs. 8%, P = 0.04). Acceptability of screening was deemed “very good” by patients, with median acceptability score 5 [IQR: 4–5] on a 5-point scale.

Conclusion

Over half of HIV+ patients screened in our clinic reported ≥4 ACEs, more than twice the prevalence of the general population. ACEs screening facilitated linkage of patients with high ACEs scores to mental healthcare. These results highlight the potential value of routine ACEs screening to enhance delivery of trauma-informed HIV primary care.

Disclosures

All authors: No reported disclosures.

Colonic microbiota can promote rapid local improvement of murine colitis by thioguanine independently of T lymphocytes and host metabolism

OBJECTIVE

Mercaptopurine (MP) and pro-drug azathioprine are 'first-line' oral therapies for maintaining remission in IBD. It is believed that their pharmacodynamic action is due to a slow cumulative decrease in activated lymphocytes homing to inflamed gut. We examined the role of host metabolism, lymphocytes and microbiome for the amelioration of colitis by the related thioguanine (TG).

DESIGN

C57Bl/6 mice with or without specific genes altered to elucidate mechanisms responsible for TG's actions were treated daily with oral or intrarectal TG, MP or water. Disease activity was scored daily. At sacrifice, colonic histology, cytokine message, caecal luminal and mucosal microbiomes were analysed.

RESULTS

Oral and intrarectal TG but not MP rapidly ameliorated spontaneous chronic colitis in Winnie mice (point mutation in Muc2 secretory mucin). TG ameliorated dextran sodium sulfate-induced chronic colitis in wild-type (WT) mice and in mice lacking T and B lymphocytes. Remarkably, colitis improved without immunosuppressive effects in the absence of host hypoxanthine (guanine) phosphoribosyltransferase (Hprt)-mediated conversion of TG to active drug, the thioguanine nucleotides (TGN). Colonic bacteria converted TG and less so MP to TGN, consistent with intestinal bacterial conversion of TG to so reduce inflammation in the mice lacking host Hprt. TG rapidly induced autophagic flux in epithelial, macrophage and WT but not Hprt^-/- fibroblast cell lines and augmented epithelial intracellular bacterial killing.

CONCLUSIONS

Treatment by TG is not necessarily dependent on the adaptive immune system. TG is a more efficacious treatment than MP in Winnie spontaneous colitis. Rapid local bacterial conversion of TG correlated with decreased intestinal inflammation and immune activation.

JIP4 is a PLK1 binding protein that regulates p38MAPK activity in G2 phase

Cell cycle progression from G2 phase into mitosis is regulated by a complex network of mechanisms, all of which finally control the timing of Cyclin B/CDK1 activation. PLK1 regulates a network of events that contribute to regulating G2/M phase progression. Here we have used a proteomics approach to identify proteins that specifically bind to the Polobox domain of PLK1. This identified a panel of proteins that were either associated with PLK1 in G2 phase and/or mitosis, the strongest interaction being with the MAPK scaffold protein JIP4. PLK1 binding to JIP4 was found in G2 phase and mitosis, and PLK1 binding was self-primed by PLK1 phosphorylation of JIP4. PLK1 binding is required for JIP4-dependent p38MAPK activation in G2 phase during normal cell cycle progression, but not in either G2 phase or mitotic stress response. Finally, JIP4 is a target for caspase-dependent cleavage in mitotically arrested cells. The role for the PLK1-JIP4 regulated p38MAPK activation in G2 phase is unclear, but it does not affect either progression into or through mitosis.

Cyclin A/Cdk2 regulates Cdh1 and claspin during late S/G2 phase of the cell cycle

Whereas many components regulating the progression from S phase through G2 phase into mitosis have been identified, the mechanism by which these components control this critical cell cycle progression is still not fully elucidated. Cyclin A/Cdk2 has been shown to regulate the timing of Cyclin B/Cdk1 activation and progression into mitosis although the mechanism by which this occurs is only poorly understood. Here we show that depletion of Cyclin A or inhibition of Cdk2 during late S/early G2 phase maintains the G2 phase arrest by reducing Cdh1 transcript and protein levels, thereby stabilizing Claspin and maintaining elevated levels of activated Chk1 which contributes to the G2 phase observed. Interestingly, the Cyclin A/Cdk2 regulated APC/C(Cdh1) activity is selective for only a subset of Cdh1 targets including Claspin. Thus, a normal role for Cyclin A/Cdk2 during early G2 phase is to increase the level of Cdh1 which destabilises Claspin which in turn down regulates Chk1 activation to allow progression into mitosis. This mechanism links S phase exit with G2 phase transit into mitosis, provides a novel insight into the roles of Cyclin A/Cdk2 in G2 phase progression, and identifies a novel role for APC/C(Cdh1) in late S/G2 phase cell cycle progression.

Comparisons of microbiological evaluations of selected kitchen areas with visual inspections for preventing potential risk of foodborne outbreaks in food service operations

Most local health departments utilize visual, but not microbiological, methods when inspecting food service operations. To evaluate the marginal utility of microbial testing for minimizing potential risks of foodborne outbreaks in restaurants, swab samples were taken from handwashing sink faucets, freshly cleaned and sanitized food-contact surfaces, and from cooler or freezer door handles in 70 of 350 category-three (high-risk) food service operations in Toledo, Ohio. The swabs were inoculated onto different selective media, and standard procedures were used to identify pathogenic and nonpathogenic bacteria. Microbiological evaluations of the sampled food service operations were compared with visual inspection reports, using a numeric rating scale. Enteric bacteria (that may indicate fecal contamination) were found on food contact surfaces, on cooler or freezer door handles, and on handwashing sink faucets in 86, 57, and 53% of the food service operations, respectively. Approximately 27, 40, and 33% of the restaurants received visual ratings of very poor to poor, fair, and good to very good, respectively. In comparison, 10, 17, and 73% of the restaurants received microbiological rating scores of very poor to poor, fair, and good to very good, respectively. Restaurants with trained personnel received significantly higher visual rating scores than restaurants without trained personnel (P < 0.01). Although more restaurants received poor rating scores by visual inspection than by microbiological evaluation, the presence of fecal bacteria from different sites in more than 50% of the food service operations indicated that visual inspection alone might not be sufficient for minimizing potential risk for foodborne disease outbreaks. Therefore, we recommend periodic microbiological evaluation of high-risk food service operations, in addition to visual inspection, for minimizing the risk of foodborne disease outbreaks.

Bcl-2 overexpression attenuates dopamine-induced apoptosis in an immortalized neural cell line by suppressing the production of reactive oxygen species

Parkinson's disease is a neurodegenerative disease that is consequent to the loss of brain dopamine (DA) cells. These abnormalities are thought, in part, to be a manifestation of increased free radical production during the metabolism of catecholamines. The antiapoptic agent, bcl-2, has been shown to protect cells against the toxic effects of reactive oxygen species (ROS). Thus, we tested whether bcl-2 could attenuate the toxic effects of DA on immortalized neural cells. Our results show that DA caused dose-dependent cell death. The use of confocal microscopy and flow cytometry demonstrated that DA caused cell death through an apoptotic process. Moreover, DA caused a marked increase in ROS in these cells. Furthermore, overexpression of bcl-2 caused significant protection against DA-induced apoptosis. These results are discussed in terms of their support for a role of bcl-2 in the development of Parkinson's disease.

Stress-induced rat intestinal mast cell intragranular activation and inhibitory effect of sulfated proteoglycans

Cyclic vomiting syndrome is characterized by sudden episodes of vomiting and abdominal pain. It occurs primarily in children, is exacerbated by stress, and is often considered a migraine equivalent. Migraines have been linked to mast cells, which are often found close to neurons where they are activated by neuropeptides. We investigated the ultrastructural appearance of rat ileal brush border and mast cells following acute stress by immobilization. The effect of sulfated proteoglycans heparin and chondroitin sulfate was also tested on mast cell histamine secretion. Ileal brush border appeared intact in control animals, but was shorter and exhibited intercellular gaps after 30 min of acute immobilization stress. Mast cell activation in control rats was minimal, while stress induced obvious signs of activation as judged from disappearance of secretory granule electron dense contents. However, these intragranular changes were not accompanied by typical degranulation through exocytosis. Treatment of purified homogeneic rat peritoneal mast cells with 10(-4) M heparin or chondroitin sulfate 30 min prior to stimulation with 0.5 microg/ml compound 48/80 decreased histamine release by over 70% and 50% (P < 0.05), respectively. These results suggest the possible usefulness of chondroitin sulfate in conditions such as cyclic vomiting syndrome.

System A amino acid transporter activity in human placental microvillous membrane vesicles in relation to various anthropometric measurements in appropriate and small for gestational age babies

Fetal growth and development is dependent on the transfer of amino acids from maternal to fetal blood across the microvillous plasma membrane (MVM) and basal plasma membrane of placental syncytiotrophoblast. The aim of this study was to determine the relationship of system A amino acid transporter (SysA) activity in MVM to a variety of measurements of size at birth in a group of term small for gestational age (SGA) babies and in a group of appropriate for gestational age (AGA) babies. Mean SysA activities (nmol/mg vesicle protein/30 s +/- SEM) were: SGA, 0.027 +/- 0.004 (n = 25) and AGA, 0.045 +/- 0.005 (n = 24); p = 0.006. Spearman rank correlations were calculated for SGA (n = 19-25) and AGA (n = 21-24) groups for SysA activity against the following anthropometric measurements: abdominal circumference, birth weight, length, midarm circumference (MAC), head circumference, midarm circumference:head circumference ratio, placental weight (PW), placental ratio (placental weight:birth weight), birth weight:length ratio, Ponderal index (birth weight/length3) and triceps and subscapular skin-fold thicknesses (tsft and ssft). In SGA babies, SysA activity was positively correlated (p < 0.05) with subscapular skin-fold thicknesses (r = 0.48), triceps skin-fold thicknesses (r = 0.42), PW (r = 0.42), and placental ratio (r = 0.46). In AGA babies, the only significant correlation was an inverse one with placental ratio (r = -0.50). These data suggest there are differences in the relationship between placental SysA activity and fetal proportion in term AGA compared with SGA babies.

Molecular and phenotypic analysis of Candida dubliniensis: a recently identified species linked with oral candidosis in HIV-infected and AIDS patients

The discovery and characterisation of a novel species of Candida, termed Candida dubliniensis, associated with oral candidosis in HIV-infected individuals is described. These organisms share several phenotypic characteristics in common with Candida albicans and Candida stellatoidea, including the ability to produce germ tubes and chlamydospores. However, in contrast to these latter two species, C. dubliniensis isolates produce abundant chlamydospores, which are often arranged in contiguous pairs, triplets and other multiples suspended from a single suspensor cell. They belong to C. albicans serotype A and exhibit atypical substrate assimilation profiles. Genomic DNA fingerprinting analysis with the C. albicans-specific probe 27A and five different oligonucleotide probes consisting of short repeat sequence-containing motifs, demonstrated that C. dubliniensis has a distinct genomic organisation relative to C. albicans and C. stellatoidea. This was confirmed by karyotype analysis and random amplified polymorphic DNA (RAPD) analysis. Comparison of 500 bp of the V3 variable region of the large ribosomal subunit genes from 14 separate C. dubliniensis isolates and the corresponding sequences from C. albicans, C. stellatoidea, C. tropicalis, C. glabrata, C. parapsilosis, C. kefyr and C. krusei demonstrated that the C. dubliniensis isolates formed a homogenous cluster (100% similarity), representing a discrete taxon within the genus Candida that was significantly different from the other species analysed.

Adaptation of cholinergic enteric neuromuscular transmission in diabetic rat small intestine

Representative longitudinal muscle strips (6 x 10 mm) from distal small intestine were obtained from rats after 1, 2, and 3 mo of streptozocin-induced diabetes. The strips were stretched to their optimum lengths and subjected to electrical field stimulation (1-ms pulse duration, 30-270 mA, 10 Hz) in the presence of Krebs solution and Krebs solution plus 10(-6) M atropine. Field stimulation produced atropine-sensitive and atropine-resistant contractions in all strips. After 1 mo, significant differences in the amplitudes of the atropine-sensitive contractions were found between the diabetic rats and nondiabetic controls. Insulin-treated diabetic rats showed contraction responses that were intermediate in amplitude. After 2 mo, the difference between the control and diabetic groups was less evident but still significant. After 3 mo, the previously noted difference in the atropine-sensitive contractions between the diabetic and control groups had resolved. No significant differences among the three groups were noted in the amplitudes of the atropine-resistant contractions. Field stimulation delivered at pulse durations of 50 ms in the presence of neural blockade with tetrodotoxin (5 x 10(-6) M) produced similar contraction amplitudes among the three groups at any respective time phase of the study. Dose-response studies of intestinal muscle after 3 mo of untreated diabetes showed normal tension development to both bethanechol chloride and physostigmine. These results indicate that streptozocin-induced diabetes is acutely associated with defective cholinergic neuromuscular transmission in the myenteric plexus of the distal small intestine. The abnormality is less evident after 2 mo of untreated diabetes and resolves spontaneously after 3 mo. Insulin treatment appears to accelerate this resolution.

Structural and functional characteristics of muscle from diabetic rodent small intestine

After 30 days of streptozotocin-induced diabetes, the small intestine from untreated diabetic, insulin-treated diabetic, and nondiabetic rodents was excised in toto and measured. Despite a net loss in body weight, the diabetic animals showed a near twofold increase in small intestinal weight. This was characterized by a 148% increase in mucosal mass as well as a 39% increase in intestinal smooth muscle mass (P less than 0.05, respectively). The diabetic intestine was significantly longer and had a greater diameter and surface area. Diabetes significantly increased mucosal mass per unit surface area but produced an insignificant decrease in smooth muscle mass per unit surface area. Insulin treatment of the diabetic animals prevented the increase in total mucosal mass and mucosal mass per unit surface area. Insulin treatment also prevented the increase in smooth muscle mass, but reduced smooth muscle mass per unit surface area to a level significantly less than that found in nondiabetic intestine. In vitro dose-response studies of circular and longitudinal small intestinal muscle from the diabetic animals showed normal tension development and sensitivity to both bethanechol chloride and physostigmine. These observations show that the diabetic state produces alterations in not only mucosal but also smooth muscle mass in the small intestine. However, despite these morphological changes, diabetic intestinal smooth muscle retains its sensitivity to cholinergic stimulation and its capacity for tension generation.

Age-related changes in enteric neuromuscular transmission

Proximal and distal rat small intestine from 4-, 5- and 6-month-old rats were cut into strips measuring 6.0 X 10.0 mm. Longitudinal strips were cut along the oral-caudal axis of the intestine while circular strips were cut 90 degrees to that axis. The strips were stretched to their optimum lengths and subjected to electrical field stimulation (0.1-1.0 msec pulse duration, 30-270 mA, 1-26 Hz) in the presence of Krebs' solution and Krebs' solution plus 10(-6) M atropine. Field stimulation produced atropine-sensitive and atropine-resistant contractions in these tissues. Significant differences among the three groups were found in the amplitudes of atropine-sensitive contractions in strips from proximal longitudinal muscle. The 6-month-old animals showed the highest amplitude contractions and the 4-month-old the lowest, whereas the 5-month-old animals showed contractions that were intermediate in amplitude. No significant differences were noted among the atropine-resistant contractions. Field stimulation delivered at pulse durations of 5.0 and 50.0 msec in the presence of neural blockade with tetrodotoxin (5 X 10(-6) M) produced similar contraction amplitudes among the three groups. These results show that tension development produced by field stimulation of the proximal intestine increases significantly with age. The increases appear to be due to age-related differences in cholinergic neuromuscular transmission.

Evidence for muscarinic inhibitory neurotransmission in rodent small intestine

The influence of cholinergic and noncholinergic inhibitory nerves was examined in circular and longitudinal muscle from the duodenum. Rodent proximal small intestine was cut into strips measuring 6.0 x 10.0 mm. Strips cut along the oral-caudal axis were called longitudinal strips, whereas those cut 90 degrees to that axis were called circular strips. The strips were stretched to their optimal lengths and subjected to electrical field stimulation in the presence of various concentrations of atropine, pirenzepine or McN-A-343-11. All three drugs inhibited field-stimulated contraction responses and produced or augmented relaxation responses in both muscle layers. All relaxation responses were abolished by tetrodotoxin, indicating they were due to excitation of inhibitory nerves. For each response examined atropine was significantly more potent than pirenzepine (relative potency ratio, 13.36-95.74). The inhibitory effect of McN-A-343-11 on longitudinal muscle was antagonized by both atropine and pirenzepine, indicating the recruitment of cholinergic inhibitory nerves. Neither atropine nor pirenzepine had any effects on inhibitory responses produced by McN-A-343-11 in circular muscle, indicating the recruitment of noncholinergic inhibitory nerves. McN-A-343-11 also increased spontaneous contraction amplitudes in both muscle layers by a direct (tetrodotoxin-resistant) effect on smooth muscle. This effect was also antagonized by atropine and pirenzepine. Thus, both cholinergic and noncholinergic nerves participate in inhibitory neuromuscular transmission in the small intestine. Circular muscle is dominated by a noncholinergic inhibitory innervation. Longitudinal muscle appears to be controlled by both cholinergic and noncholinergic inhibitory nerves.

Evidence for diminished inhibitory neuromuscular transmission in distal small intestine

The influence of myenteric nerves on duodenal muscle contraction and relaxation was examined in vitro and compared with muscle responses from the ileum. Proximal and distal rat small intestine was cut into strips measuring 6.0 X 10.0 mm. Strips cut along the oral-caudal axis were called longitudinal strips, whereas those cut 90 degrees to that axis were called circular strips. The strips were stretched to their optimal lengths and subjected to electrical field stimulation (0.1-1.0 msec pulse duration, 30-300 mA, 2-26 Hz) in the presence of Krebs' solution and Krebs' plus atropine, 10(-6) M. Field stimulation produced contraction responses that were inhibited by atropine and relaxation responses that were augmented by atropine. Muscarinic blockade abolished completely contraction in circular muscle, but atropine-resistant contractions persisted in the longitudinal strips. Proximal muscle showed significantly greater relaxation responses compared to distal muscle (P less than .05) at nearly all parameters of pulse duration, current and frequency. Contraction and relaxation amplitudes were significantly greater in longitudinal than respective circular muscle (P less than .05) at either site in the intestine. Thus, not only do the two muscle layers differ in their respective nerve supplies, but inhibitory neuromuscular transmission appears to have a greater influence in proximal than distal intestine.

Evidence for abnormal cholinergic neuromuscular transmission in diabetic rat small intestine

Proximal and distal rat small intestine from control, diabetic, and insulin-treated diabetic rats was cut into strips measuring 6.0 X 10.0 mm. Strips cut along the oral-caudal axis were called longitudinal strips, while those cut 90 degrees to that axis were called circular strips. The strips were stretched to their optimum lengths and subjected to electrical field stimulation (0.1-1.0-ms pulse duration, 30-270 mA, 1-26 Hz) in the presence of Krebs' solution and Krebs' solution plus 10(-6) M atropine. Field stimulation produced atropine-sensitive and atropine-resistant contractions in all strips. Significant differences among the three groups were found in the amplitudes of atropine-sensitive contractions in strips from distal longitudinal muscle. Controls showed the highest amplitude contractions and diabetics the lowest, whereas the insulin-treated diabetics showed contractions intermediate in amplitude. No significant differences were noted among the atropine-resistant contractions. Field stimulation delivered at pulse durations of 5.0 and 50.0 ms in the presence of neural blockade with tetrodotoxin (5 X 10(-6) M) produced similar contraction amplitudes among the three groups. These results suggest that streptozotocin-induced diabetes mellitus is associated with defective cholinergic neuromuscular transmission in the myenteric plexus of the distal small intestine. Insulin therapy seems to improve the abnormality.

Effect of cholinergic agonists on muscle from rodent proximal and distal small intestine

Proximal and distal rat small intestine was cut into strips measuring 6.0 X 10.0 mm. Strips cut along the oral-caudal axis were called longitudinal strips, whereas those cut 90 degrees to that axis were called circular strips. Stress in circular and longitudinal muscle strips was measured continuously as they were superfused with acetylcholine, carbamylcholine, methacholine, bethanechol, or physostigmine. Resting stress during stretch, acetylcholine-stimulated active stress, and total stress were determined. Proximal circular muscle was five times as sensitive to acetylcholine as distal circular muscle (p less than 0.05); proximal longitudinal muscle was 2.8 times as sensitive to bethanechol as distal muscle (p less than 0.05). Resting, active, and total stress were similar in proximal and distal muscle, but circular muscle showed nearly twice the resting stress of longitudinal muscle at either proximal or distal sites (p less than 0.05). Physostigmine (10(-6) M) increased acetylcholine-stimulated active stress in proximal and distal circular muscle by 29% and 70%, respectively (p less than 0.05), but not in longitudinal muscle (p greater than 0.05). This difference between proximal and distal circular muscle (41%) was also significant (p less than 0.05). Thus, the proximal and distal muscle of the rat small intestine differs in its sensitivity to various cholinergic agonists, but not in its length-stress properties.

Pharmacokinetics of an osmotically controlled delivery indomethacin preparation in normal volunteers

Indomethacin is still used commonly for the treatment of rheumatic diseases but is associated with side effects, particularly headache, in a number of patients. A controlled or sustained release formulation of indomethacin might provide lower peak plasma levels and thus reduce side effects while still maintaining adequate plasma levels to control pain and inflammation. In this single dose crossover study, normal volunteers received the new formulation of indomethacin (Indocid GITS 6/85) fasting or with a standard meal, indomethacin 75 mg with a standard meal or indomethacin 25 mg three times daily with a standard meal. Plasma concentration data showed that peak plasma levels were reduced but the area under the plasma concentration curve was not significantly different between the four treatments.

The effects of the transcendental meditation and TM-Sidhi program on the aging process

To evaluate the effects of the Transcendental Meditation (TM) and TM-Sidhi program on the aging process, a standardized test of biological aging, utilizing auditory threshold, near point vision, and systolic blood pressure, was given to a cross-sectional group (N = 84) with a mean age of 53 years. There were 11 controls, 33 short-term TM and TM-Sidhi participants, and 40 long-term participants. The mean biological age of the controls was 2.2 years younger than for the general population; of the short-term TM subjects, 5.0 years younger; of the long-term TM subjects, 12.0 years younger. The difference between the groups was significant covarying for a diet factor. Also, there was a significant correlation between length of time practicing the TM program and biological age (r = -0.46). Together with numerous physiological and psychological studies conducted on the TM and TM-Sidhi program, this study suggests that the TM program may affect certain neural mechanisms which in turn influence age correlated physiological variables.