Association of anorexia/appetite loss with malnutrition and mortality in older populations: A systematic literature review

Anorexia/appetite loss in older subjects is frequently underrecognized in clinical practice, which may reflect deficient understanding of clinical sequelae. Therefore, we performed a systematic literature review to assess the morbidity and mortality burden of anorexia/appetite loss in older populations. Following PRISMA guidelines, searches were run (1 January 2011 to 31 July 2021) in PubMed, Embase® and Cochrane databases to identify English language studies of adults aged ≥ 65 years with anorexia/appetite loss. Two independent reviewers screened titles, abstracts and full text of identified records against pre-defined inclusion/exclusion criteria. Population demographics were extracted alongside risk of malnutrition, mortality and other outcomes of interest. Of 146 studies that underwent full-text review, 58 met eligibility criteria. Most studies were from Europe (n = 34; 58.6%) or Asia (n = 16; 27.6%), with few (n = 3; 5.2%) from the United States. Most were conducted in a community setting (n = 35; 60.3%), 12 (20.7%) were inpatient based (hospital/rehabilitation ward), 5 (8.6%) were in institutional care (nursing/care homes) and 7 (12.1%) were in other (mixed or outpatient) settings. One study reported results separately for community and institutional settings and is counted in both settings. Simplified Nutritional Appetite Questionnaire (SNAQ Simplified, n = 14) and subject-reported appetite questions (n = 11) were the most common methods used to assess anorexia/appetite loss, but substantial variability in assessment tools was observed across studies. The most commonly reported outcomes were malnutrition and mortality. Malnutrition was assessed in 15 studies, with all reporting a significantly higher risk of malnutrition in older individuals with anorexia/appetite loss (vs. without) regardless of country or healthcare setting (community n = 9, inpatient n = 2, institutional n = 3, other n = 2). Of 18 longitudinal studies that assessed mortality risk, 17 (94%) reported a significant association between anorexia/appetite loss and mortality regardless of either healthcare setting (community n = 9, inpatient n = 6, institutional n = 2) or method used to assess anorexia/appetite loss. This association between anorexia/appetite loss and mortality was observed in cohorts with cancer (as expected) but was also observed in older populations with a range of comorbid conditions other than cancer. Overall, our findings demonstrate that, among individuals aged ≥ 65 years, anorexia/appetite loss is associated with increased risk of malnutrition, mortality and other negative outcomes across community, care home and hospital settings. Such associations warrant efforts to improve and standardize screening, detection, assessment and management of anorexia/appetite loss in older adults.

BREADTH OF ADVERSE OUTCOMES ASSOCIATED WITH ANOREXIA/APPETITE LOSS IN OLDER POPULATIONS

The scope of the clinical problem of anorexia or appetite loss (AL) in older populations is potentially under-appreciated. A systematic literature review (SLR) was conducted following PRISMA guidelines to summarize associations of anorexia/AL in older adults with a range of clinical outcomes. Searches were run January/1/2011–July/31/2021 in PubMed, Embase®, and Cochrane databases to identify English-language studies of adults (aged ≥65 years) with anorexia/AL. Two independent reviewers screened titles/abstracts and full text against pre-defined inclusion/exclusion criteria. In all, 146 studies underwent full-text review; 58 met eligibility criteria. Most were from Europe (34/58 [58.6%]) or Asia (16/58 [27.6%]); only 3 (5.2%) were from the United States (US). Although mortality (n=18) and malnutrition (n=15) were the most reported outcomes, no US study reported on these outcomes. Other commonly reported outcomes included sarcopenia (n=7), functional status (n=6), need for increased care (n=6), and hospitalization (n=4). Significant associations of anorexia/AL were most consistently observed with mortality (17/18 studies), malnutrition (15/15 studies), and functional status (5/6 studies). Although the overall number of studies is small, associations have emerged with falls (2/3 studies), health related quality of life (2/3 studies), depression (2/2 studies), and cognition (2/2 studies). However, associations with hospitalization (1/4 studies), sarcopenia as assessed by muscle strength (2/4 studies) or by muscle mass (1/3 studies), and need for increased care (3/6 studies) were less consistent. Together, these studies highlight the breadth of adverse outcomes associated with anorexia/AL in older populations and a need for more US-based research into this common clinical problem.

Feasibility of somatostatin receptor-targeted imaging for detection of myocardial inflammation: A pilot study

BACKGROUND

Gallium-68 Dotatate binds preferentially to somatostatin receptor (sstr) subtype-2 (sstr-2) on inflammatory cells. We aimed at investigating the potential clinical use of sstr-targeted imaging for the detection of myocardial inflammation.

METHODS

Thirteen patients, with suspected cardiac sarcoidosis (CS) based on clinical history and myocardial uptake on recent fluorine-18 fluorodeoxyglucose (FDG) PET, were enrolled to undergo Dotatate PET after FDG-PET (median time 37 days [IQR 25-55]). Additionally, we investigated ex-vivo the immunohistochemistry expression of sstr-2 in 3 explanted sarcoid hearts.

RESULTS

All FDG scans showed cardiac uptake (focal/multifocal = 6, focal on diffuse/heterogeneous = 7), and 46% (n = 6) extra-cardiac uptake (mediastinal/hilar). In comparison, Dotatate scans showed definite abnormal cardiac uptake (focal/multifocal) in 4 patients, probably abnormal (heterogenous/patchy) in 3, and negative uptake in 6 cases. Similarly, 6 patients had increased mediastinal/hilar Dotatate uptake. Overall concordance of FDG and Dotatate uptake was 54% in the heart and 100% for thoracic nodal activity. Quantitatively, FDG maximum standardized uptake value was 5.0 times [3.8-7.1] higher in the heart, but only 2.25 times [1.7-3.0; P = .019] higher in thoracic nodes relative to Dotatate. Ex-vivo, sstr-2 immunostaining was weakly seen within well-formed granulomas in all 3 examined sarcoid heart specimens with no significant staining of background myocardium or normal myocardium.

CONCLUSION

Our preliminary data suggest that, compared to FDG imaging, somatostatin receptor-targeted imaging may be less sensitive for the detection of myocardial inflammation, but comparable for detecting extra-cardiac inflammation.

Electrocardiographic features of immune checkpoint inhibitor associated myocarditis

Background

Myocarditis is a highly morbid complication of immune checkpoint inhibitor (ICI) use that remains inadequately characterized. The QRS duration and the QTc interval are standardized electrocardiographic measures that are prolonged in other cardiac conditions; however, there are no data on their utility in ICI myocarditis.

Methods

From an international registry, ECG parameters were compared between 140 myocarditis cases and 179 controls across multiple time points (pre-ICI, on ICI prior to myocarditis, and at the time of myocarditis). The association between ECG values and major adverse cardiac events (MACE) was also tested.

Results

Both the QRS duration and QTc interval were similar between cases and controls prior to myocarditis. When compared with controls on an ICI (93±19 ms) or to baseline prior to myocarditis (97±19 ms), the QRS duration prolonged with myocarditis (110±22 ms, p<0.001 and p=0.009, respectively). In contrast, the QTc interval at the time of myocarditis (435±39 ms) was not increased compared with pre-myocarditis baseline (422±27 ms, p=0.42). A prolonged QRS duration conferred an increased risk of subsequent MACE (HR 3.28, 95% CI 1.98 to 5.62, p<0.001). After adjustment, each 10 ms increase in the QRS duration conferred a 1.3-fold increase in the odds of MACE (95% CI 1.07 to 1.61, p=0.011). Conversely, there was no association between the QTc interval and MACE among men (HR 1.33, 95% CI 0.70 to 2.53, p=0.38) or women (HR 1.48, 95% CI 0.61 to 3.58, p=0.39).

Conclusions

The QRS duration is increased in ICI myocarditis and is associated with increased MACE risk. Use of this widely available ECG parameter may aid in ICI myocarditis diagnosis and risk-stratification.

Laser-Induced Periodic Surface Structure Enhances Neuroelectrode Charge Transfer Capabilities and Modulates Astrocyte Function

The brain machine interface (BMI) describes a group of technologies capable of communicating with excitable nervous tissue within the central nervous system (CNS). BMIs have seen major advances in recent years, but these advances have been impeded because of a temporal deterioration in the signal to noise ratio of recording electrodes following insertion into the CNS. This deterioration has been attributed to an intrinsic host tissue response, namely, reactive gliosis, which involves a complex series of immune mediators, resulting in implant encapsulation via the synthesis of pro-inflammatory signaling molecules and the recruitment of glial cells. There is a clinical need to reduce tissue encapsulation in situ and improve long-term neuroelectrode functionality. Physical modification of the electrode surface at the nanoscale could satisfy these requirements by integrating electrochemical and topographical signals to modulate neural cell behavior. In this study, commercially available platinum iridium (Pt/Ir) microelectrode probes were nanotopographically functionalized using femto/picosecond laser processing to generate laser-induced periodic surface structures (LIPSS). Three different topographies and their physical properties were assessed by scanning electron microscopy and atomic force microscopy. The electrochemical properties of these interfaces were investigated using electrochemical impedance spectroscopy and cyclic voltammetry. The in vitro response of mixed cortical cultures (embryonic rat E14/E17) was subsequently assessed by confocal microscopy, ELISA, and multiplex protein array analysis. Overall LIPSS features improved the electrochemical properties of the electrodes, promoted cell alignment, and modulated the expression of multiple ion channels involved in key neuronal functions.

Quantification of pleural effusions on thoracic ultrasound in acute heart failure

BACKGROUND

Although pleural effusions are common among patients with acute heart failure, the relevance of pleural effusion size assessed on thoracic ultrasound has not been investigated systematically.

METHODS

In this prospective observational study, we included patients hospitalised for acute heart failure and performed a thoracic ultrasound early after admission (thoracic ultrasound 1) and at discharge (thoracic ultrasound 2) independently of routine clinical management. A semiquantitative score was applied offline blinded to clinical findings to categorise and monitor pleural effusion size.

RESULTS

Among 188 patients (median age 72 years, 62% men, 78% white, median left ventricular ejection fraction 38%), pleural effusions on thoracic ultrasound 1 were present in 66% of patients and decreased in size during the hospitalisation in 75% based on the pleural effusion score (P<0.0001). Higher values of the pleural effusion score were associated with higher pleural effusion volumes on computed tomography (P<0.001), higher NT-pro brain natriuretic peptide values (P=0.001) and a greater number of B-lines on lung ultrasound (P=0.004). Nevertheless, 47% of patients were discharged with persistent pleural effusions, 19% with large effusions. However, higher values of the pleural effusion score on thoracic ultrasound 2 did not identify patients at increased risk of 90-day heart failure rehospitalisations or death (adjusted hazard ratio (HR) 1.05, 95% confidence interval (CI) 0.92-1.19; P=0.46) whereas seven or more B-lines on lung ultrasound at discharge were independently associated with adverse events (adjusted HR 2.43, 95% CI 1.11-5.37; P=0.027).

CONCLUSION

Among patients with acute heart failure, pleural effusions are associated with other clinical, imaging and laboratory markers of congestion and improve with heart failure therapy. The prognostic relevance of persistent pleural effusions at discharge should be investigated in larger studies.

Cardiorespiratory fitness and cardiovascular mortality after prolonged androgen deprivation therapy for prostate cancer

11576

Background: Androgen deprivation therapy (ADT) plays a pivotal role in management of prostate cancer (PC), with prolonged ADT favored over short-term use in the definitive treatment of high risk PC with radiation. Objectives: To compare cardiorespiratory fitness (CRF) and cardiovascular (CV) mortality among patients with PC with and without ADT exposure, and to explore how duration of ADT exposure influences CRF and CV mortality risk. Methods: This is a retrospective study of patients referred for exercise treadmill testing (ETT) after a diagnosis of PC. PC risk classification was based on Gleason score (GS) at diagnosis: high risk GS ≥ 8, intermediate risk GS= 7, and low risk GS ≤ 6. CRF was categorized according to metabolic equivalents (METs): METs ≥ 8 defined as good CRF and METs < 8 as reduced CRF. ADT exposure was grouped as short-term (≤ 6 months) versus prolonged (> 6 months). Results: 616 patients underwent an ETT a median of 4.8 years (interquartile range: 2.0-7.9) after diagnosis of PC. 150 patients (24.3%) received ADT prior to ETT; 51 with short-term versus 99 with prolonged exposure. 524 (85.1%) patients had ≥ 2 CV risk factors, and 28 CV deaths occurred over 4.2 (interquartile range: 2.3-7.1) years following the ETT. Reduced CRF was more frequent among ADT-exposed versus ADT-naive patients (48.7 versus 32.6%, p< 0.001). Prolonged ADT was associated with reduced CRF (odds ratio (OR): 2.71; 95% confidence interval (CI): 1.31-5.61; p=0.007) and increased CV mortality (hazard ratio (HR): 3.87; 95% CI: 1.16-12.96; p=0.03) in adjusted analyses. In contrast, short-term ADT exposure was not independently associated with either reduced CRF (OR 1.71; 95% CI: 1.00-2.94); p=0.05) or CV mortality (HR: 1.60; 95% CI: 0.51-5.01; p=0.42). Conclusions: Among patients with PC and high baseline CV risk, > 6 months ADT exposure but not less was associated with reduced CRF and increased CV mortality. Reduced CRF may in part mediate increased CV mortality risk. Exercise interventions concurrent with prolonged ADT warrants investigation to potentially offset risk.

Analysis of carfilzomib cardiovascular safety profile across relapsed and/or refractory multiple myeloma clinical trials

Carfilzomib is a selective proteasome inhibitor approved for the treatment of relapsed and/or refractory multiple myeloma (RRMM). It has significantly improved outcomes, including overall survival (OS), and shown superiority vs standard treatment with lenalidomide plus dexamethasone and bortezomib plus dexamethasone. The incidence rate of cardiovascular (CV) events with carfilzomib treatment has varied across trials. This analysis evaluated phase 1-3 trials with >2000 RRMM patients exposed to carfilzomib to describe the incidence of CV adverse events (AEs). In addition, the individual CV safety data of >1000 patients enrolled in the carfilzomib arm of phase 3 studies were compared with the control arms to assess the benefit-risk profile of carfilzomib. Pooling data across carfilzomib trials, the CV AEs (grade ≥3) noted included hypertension (5.9%), dyspnea (4.5%), and cardiac failure (4.4%). Although patients receiving carfilzomib had a numeric increase in the rates of any-grade and grade ≥3 cardiac failure, dyspnea, and hypertension, the frequency of discontinuation or death due to these cardiac events was low and comparable between the carfilzomib and control arms. Serial echocardiography in a blinded cardiac substudy showed no objective evidence of cardiac dysfunction in the carfilzomib and control arms. Moreover, carfilzomib had no significant effect on cardiac repolarization. Our results, including the OS benefit, showed that the benefit of carfilzomib treatment in terms of reducing progression or death outweighed the risk for developing cardiac failure or hypertension in most patients. Appropriate carfilzomib administration and risk factor management are recommended for elderly patients and patients with underlying risk factors.

Cardiac autonomic dysfunction in breast cancer survivors

10057

Background: Cardiac autonomic dysfunction (AD) has been associated with increased cardiovascular (CV) and all-cause mortality in several diseases. We evaluated the prevalence, functional and prognostic significance of cardiac AD in a cohort of breast cancer (BC) survivors referred for exercise treadmill testing (ETT). Methods: Cardiac AD was defined as the presence of both an elevated resting heart rate (HR ≥ 80 beats per minute) and abnormal HR recovery (HRR ≤ 12 beats per minute if active cool down, or ≤ 18 beats per minute if passive recovery) at 1 minute after peak exercise. Presence of cardiac AD, exercise capacity, and all-cause mortality were assessed in 448 women (age 62.6±10.0 years), 8.7 [range 4.5, 14.3] years from BC diagnosis, compared to 448 cancer-free, age- and sex-matched controls, all of whom were clinically referred for ETT. Results: Elevated resting HR (23.7% vs. 17.0%, p = 0.013), abnormal HRR (25.9% vs. 20.3%, p = 0.048), and cardiac AD (8.0% vs. 4.2%, p = 0.025) were more prevalent in BC survivors than controls. BC survivors with cardiac AD had reduced exercise capacity compared to those without AD (Table). Among controls, cardiac AD was not associated with decreased exercise capacity. Among BC survivors (age-adjusted hazard ratio 1.90 (95% CI 0.78-4.62) and controls (age-adjusted hazard ratio 4.09 (95% CI 0.49-34.18), cardiac AD was not associated with increased all-cause mortality. Conclusions: Among patients referred for ETT, BC survivors have an increased prevalence of cardiac AD relative to controls. Cardiac AD is associated with decreased exercise capacity, but not increased all-cause mortality, in BC survivors. Available strategies to modulate cardiac AD may improve functional capacity in BC survivors. Table: Impact of markers of cardiac AD on exercise capacity. [Table: see text]

Cardiac Outcomes of Patients Receiving Adjuvant Weekly Paclitaxel and Trastuzumab for Node-Negative, ERBB2-Positive Breast Cancer

IMPORTANCE

Trastuzumab is a life-saving therapy but is associated with symptomatic and asymptomatic left ventricular ejection fraction (LVEF) decline. We report the cardiac toxic effects of a nonanthracycline and trastuzumab-based treatment for patients with early-stage human epidermal growth factor receptor 2 (ERBB2, formerly HER2 or HER2/neu)-positive breast cancer.

OBJECTIVE

To determine the cardiac safety of paclitaxel with trastuzumab and the utility of LVEF monitoring in patients with node-negative, ERBB2-positive breast cancer.

DESIGN, SETTING, AND PARTICIPANTS

In this secondary analysis of an uncontrolled, single group study across 14 medical centers, enrollment of 406 patients with node-negative, ERBB2-positive breast cancer 3 cm, or smaller, and baseline LVEF of greater than or equal to 50% occurred from October 9, 2007, to September 3, 2010. Patients with a micrometastasis in a lymph node were later allowed with a study amendment. Median patient age was 55 years, 118 (29%) had hypertension, and 30 (7%) had diabetes. Patients received adjuvant paclitaxel for 12 weeks with trastuzumab, and trastuzumab was continued for 1 year. Median follow-up was 4 years.

INTERVENTIONS

Treatment consisted of weekly 80-mg/m2 doses of paclitaxel administered concurrently with trastuzumab intravenously for 12 weeks, followed by trastuzumab monotherapy for 39 weeks. During the monotherapy phase, trastuzumab could be administered weekly 2-mg/kg or every 3 weeks as 6-mg/kg. Radiation and hormone therapy were administered per standard guidelines after completion of the 12 weeks of chemotherapy. Patient LVEF was assessed at baseline, 12 weeks, 6 months, and 1 year.

MAIN OUTCOMES AND MEASURES

Cardiac safety data, including grade 3 to 4 left ventricular systolic dysfunction (LVSD) and significant asymptomatic LVEF decline, as defined by our study, were reported.

RESULTS

Overall, 2 patients (0.5%) (95% CI, 0.1%-1.8%) developed grade 3 LVSD and came off study, and 13 (3.2%) (95% CI, 1.9%-5.4%) had significant asymptomatic LVEF decline, 11 of whom completed study treatment. Median LVEF at baseline was 65%; 12 weeks, 64%; 6 months, 64%; and 1 year, 64%.

CONCLUSIONS AND RELEVANCE

Cardiac toxic effects from paclitaxel with trastuzumab, manifesting as grade 3 or 4 LVSD or asymptomatic LVEF decline, were low. Patient LVEF was assessed at baseline, 12 weeks, 6 months, and 1 year, and our findings suggest that LVEF monitoring during trastuzumab therapy without anthracyclines could be simplified for many individuals.

Breast cancer therapies and cardiomyopathy

The prevalence of chemotherapy-related cardiac disease is increasing and management demands a multidisciplinary approach from cardiologists and oncologists. Pretreatment identification of predisposing risk factors and assessment of cardiac function before and at intervals during and after therapy with cardiotoxic agents are necessary. In clinical practice, surveillance is largely performed using transthoracic echocardiography or multi-gated radionuclide angiography. Imaging strategies that detect cardiac injury before overt left ventricular systolic dysfunction provide an opportunity for early intervention and improved cardiac outcomes.

Cost burden of non-specific chest pain admissions

BACKGROUND

Non-cardiac aetiologies are common among patients presenting with chest pain.

AIM

To determine the cost of non-specific chest pain admissions to a tertiary referral, teaching hospital.

METHODS

Thrombolysis in myocardial infarction risk (TIMI) risk score, lengths of stay (LOS), investigations and diagnoses were recorded for patients admitted with chest pain. Non-specific chest pain was defined as chest pain where cardiac, pulmonary and gastroesophageal aetiologies were excluded. Costs of admissions were calculated.

RESULTS

Of 80 patients, 34 (4%) and 22 (28%) were diagnosed with non-specific chest pain and acute coronary syndrome, respectively. Non-specific chest pain admissions had a mean age of 54 (11; 35-74) years, LOS of 3.8 (2.6; 1-11) days and TIMI risk score of 1.4 (1.5; 0-5). Acute coronary syndrome admissions had a mean age of 67 (14; 43-94) years, LOS of 7.7 (4.3; 2-16) days and TIMI risk score of 3.1 (1.2; 0-5). The mean cost per non-specific chest pain admission was €3,729 (2,378; 1,034-10,468), or 48% of the mean cost per acute coronary syndrome admission of €7,667 (4,279; 1,963-16,071). Bed day costs account for >90% of overall costs. Only 7% of patients were weekend discharges. The mean interval to exercise stress test was 2.7(1.5; 1-7) days.

CONCLUSIONS

The mean costs of admission and LOS for patients with non-specific chest pain are significant. Extrapolating findings, annual national cost is estimated at approximately €71 million for this cohort, with 73,000 bed days consumed nationally. Delays from admission to tests and low percentage of weekend discharges prolong LOS.

Conflicting perspectives compromising discussions on cardiopulmonary resuscitation

Healthcare professionals, patients and their relatives are expected to discuss resuscitation together. This study aims to identify the differences in the knowledge base and understanding of these parties. Questionnaires examining knowledge and opinion on resuscitation matters were completed during interviews of randomly selected doctors, nurses and the general public. 70% doctors, 24% nurses and 0% of a public group correctly estimated survival to discharge following in-hospital resuscitation attempts. Deficiencies were identified in doctor and nurse knowledge of ethics governing resuscitation decisions. Public opinion often conflicts with ethical guidelines. Public understanding of the nature of cardiopulmonary arrests and resuscitation attempts; and of the implications of a 'Do Not Attempt Resuscitation (DNAR)' order is poor. Television medical dramas are the primary source of resuscitation knowledge. Deficiencies in healthcare professionals' knowledge of resuscitation ethics and outcomes may compromise resuscitation decisions. Educational initiatives to address deficiencies are necessary. Parties involved in discussion on resuscitation do not share the same knowledge base reducing the likelihood of meaningful discussion. Public misapprehensions surrounding resuscitation must be identified and corrected during discussion.

The structure of coxsackievirus B3 at 3.5 A resolution

BACKGROUND

Group B coxsackieviruses (CVBs) are etiologic agents of a number of human diseases that range in severity from asymptomatic to lethal infections. They are small, single-stranded RNA icosahedral viruses that belong to the enterovirus genus of the picornavirus family. Structural studies were initiated in light of the information available on the cellular receptors for this virus and to assist in the design of antiviral capsid-binding compounds for the CVBs.

RESULTS

The structure of coxsackievirus B3 (CVB3) has been solved to a resolution of 3.5 A. The beta-sandwich structure of the viral capsid proteins VP1, VP2 and VP3 is conserved between CVB3 and other picornaviruses. Structural differences between CVB3 and other enteroviruses and rhinoviruses are located primarily on the viral surface. The hydrophobic pocket of the VP1 beta-sandwich is occupied by a pocket factor, modeled as a C16 fatty acid. An additional study has shown that the pocket factor can be displaced by an antiviral compound. Myristate was observed covalently linked to the N terminus of VP4. Density consistent with the presence of ions was observed on the icosahedral threefold and fivefold axes.

CONCLUSIONS

The canyon and twofold depression, major surface depressions, are predicted to be the primary and secondary receptor-binding sites on CVB3, respectively. Neutralizing immunogenic sites are predicted to lie on the extreme surfaces of the capsid at sites that lack amino acid sequence conservation among the CVBs. The ions located on the icosahedral threefold and fivefold axes together with the pocket factor may contribute to the pH stability of the coxsackieviruses.

Vagal effects on acid and pepsin secretion and serum gastrin in duodenal ulcer and controls

To study whether the vagus sustains basal secretion and stimulates acid and pepsin differently in duodenal ulcer (DU) and non-DU, we tested 144 patients with DU and 92 nonulcer controls, using 1-hr basal secretion followed by 15 min of modified sham feeding (MSF) and after 1 hr followed by a reference maximum elicited by 6 micrograms/kg pentagastrin given subcutaneously and observed for another 1 hr. Of all subjects, 97.5% responded to MSF by raising basal acid output (BAO) at least 15%. MSF added amounts of acid equal to 26-30% of peak acid output and 30-43% of peak pepsin output, regardless of diagnosis or level of basal secretion (including hypersecretors). Speed and duration of responses were similar in DU and controls. MSF did not substantially alter serum gastrin. Males secreted more acid and pepsin than females under all conditions, differences that persisted in DU but not in controls when outputs were corrected for body weight. Male DU but not female DU patients secreted more than corresponding controls. Sham feeding is an effective stimulus with similar characteristics in controls and DU patients. There was no evidence for saturation of vagal pathways in basal hypersecretors. MSF stimulation does not appear to involve gastrin. Hypersecretion in DU derives largely from responses in male DU.

Human immunodeficiency virus type 1 DNA integration: fine structure target analysis using synthetic oligonucleotides

The target specificity of DNA strand transfer mediated by human immunodeficiency virus type 1 integrase was examined in vitro with synthetic oligonucleotides. Although insertion occurred at most locations in the target, some sites were preferred over others by at least 15-fold. Changing the nucleotide sequence of the target changed the distribution of preferred sites in complex ways, some of which included changes in target preference distant from the sequence alteration. Alignment of target sequences revealed that adenosine is preferred adjacent to the insertion site. Strand transfer occurred to within 2 nucleotides of the 3' end and to within 3 nucleotides of the 5' end of the target. This suggests that only 2 or 3 nucleotides flanking the target site are required for integration; such restricted contact with target DNA would allow integrase to insert the two ends of viral DNA into two closely spaced sites in host DNA, consistent with the concerted in vivo integration reaction that generates a 5-bp target duplication.

Reconstitution of periplasmic transport in inside-out membrane vesicles. Energization by ATP

The periplasmic histidine permease of Salmonella typhimurium has been reconstituted in inside-out vesicles (IOV) of Escherichia coli by disrupting the cells with a French press in the presence of a high concentration of the periplasmic histidine-binding protein, HisJ. Efflux from IOV, which is equivalent to uptake in whole cells, is induced by ATP. The reconstituted system depends on the presence of the membrane-bound permease proteins, HisQ, HisM, and HisP, and does not function if reconstitution is performed in the presence of a mutant HisJ protein, HisJ5625, that can bind histidine normally but can't interact properly with the membrane complex. Efflux is not induced by the nonhydrolyzable ATP analog, adenyl-5'-yl imidodiphosphate, supporting the contention that ATP hydrolysis is necessary. 8-Azido ATP inactivates IOV, indicating that the ATP effect occurs through the HisP protein, which has previously been shown to be modified by 8-azido ATP (Hobson, A., Weatherwax, R., and Ames, G.F.-L. (1984) Proc. Natl. Acad. Sci. U. S. A. 81, 733-7337). The estimated Km of the vesicles for ATP is about 200 microM. Vanadate, an inhibitor of phosphohydrolase enzymes, inhibits ATP-induced efflux. We conclude that ATP is likely to be the proximal energy source for periplasmic permeases.