Predicting bone loss following orthotopic liver transplantation

BACKGROUND: Hepatic osteodystrophy occurs in the majority of patients with advanced chronic liver disease with the abnormalities in bone metabolism accelerating following orthotopic liver transplantation (OLT). AIMS: To examine changes in bone mineral density (BMD) following OLT and to investigate factors that lead to bone loss. METHODS: Twelve patients had BMD (at both the lumbar spine (LS) and femoral neck (FN)) and biochemical markers measured preoperatively and for 24 months following OLT. RESULTS: BMD was low in 75% of patients prior to OLT and decreased significantly from baseline at the LS at three months and the FN at six months. BMD began to increase thereafter at both sites, approaching baseline values at the LS by 12 months. Bone formation markers, osteocalcin and procollagen type I carboxy propeptide, decreased immediately post-OLT, with a concomitant increase seen in the resorption markers pyridinoline and deoxypyridinoline. This resulted in a negative uncoupling index early post-OLT, that rebounded to positive values after six months. There was a significant correlation between the change in the uncoupling index between six and three months which preceded the increase in BMD at 12 months. The decrease in BMD recorded early post-OLT correlated with vitamin D levels at three months. CONCLUSIONS: Results suggest that increased resorption and inadequate formation are the major contributors to additional bone loss following OLT. Non-invasive biochemical markers precede later changes in BMD in this patient group following OLT and may have a role in investigating and planning intervention strategies to prevent bone loss in future studies.     

Artificial intelligence in gastroenterology: A state-of-the-art review

The development of artificial intelligence (AI) has increased dramatically in the last 20 years, with clinical applications progressively being explored for most of the medical specialties. The field of gastroenterology and hepatology, substantially reliant on vast amounts of imaging studies, is not an exception. The clinical applications of AI systems in this field include the identification of premalignant or malignant lesions (e.g., identification of dysplasia or esophageal adenocarcinoma in Barrett’s esophagus, pancreatic malignancies), detection of lesions (e.g., polyp identification and classification, small-bowel bleeding lesion on capsule endoscopy, pancreatic cystic lesions), development of objective scoring systems for risk stratification, predicting disease prognosis or treatment response [e.g., determining survival in patients post-resection of hepatocellular carcinoma), determining which patients with inflammatory bowel disease (IBD) will benefit from biologic therapy], or evaluation of metrics such as bowel preparation score or quality of endoscopic examination. The objective of this comprehensive review is to analyze the available AI-related studies pertaining to the entirety of the gastrointestinal tract, including the upper, middle and lower tracts; IBD; the hepatobiliary system; and the pancreas, discussing the findings and clinical applications, as well as outlining the current limitations and future directions in this field.     

Variant angina pectoris: a clinical and coronary arteriographic spectrum

The clinical course and coronary arteriographic findings in eight patients with Prinzmetal's variant angina pectoris are reviewed and contrasted to previously reported cases. In six patients with S-T-elevation inferiorly, three had normal coronary arteriograms, one had complete right coronary artery occlusion, one had diffuse triple-vessel disease, and one did not undergo coronary arteriography. In two patients with S-T-elevation anteriorly, severe stenosis of the anterior descending coronary artery was present. Medical treatment in four patients and surgical revascularization of the anterior descending coronary artery in two patients were both accompanied by marked symptomatic improvement. Spontaneous loss of angina occurred in two patients. During 17 months' mean follow-up, seven patients have remained free of angina and one died suddenly. Variant angina pectoris may be accompanied by a variety of coronary arteriographic findings and the prognosis appears more favorable than previously reported.     

Use of nifedipine in hypertrophic cardiomyopathy in infants. A report of two cases

Hypertrophic cardiomyopathy was diagnosed in two symptomatic neonates. Treatment with nifedipine, a calcium blocking agent, was encouraging and warrants further investigation.     

Effect of exercise on ventricular response to atrial fibrillation in Wolff-Parkinson-White syndrome

Ten patients with Wolff-Parkinson-White syndrome underwent cardiac electrophysiological study extended to include the induction of atrial fibrillation at maximum exercise in the upright position. This was performed using a new temporary bipolar lead with a helical active fixation tip for atrial pacing. The highest rate of atrioventricular conduction via the accessory pathway was greater during exercise than at rest in all 10 patients (mean increase 28%). In three cases the resulting ventricular rate exceeded 300 beats/min, but no patient had severe symptoms or ventricular arrhythmias. The exercise induced enhancement of accessory pathway conduction may significantly but unpredictably affect the risk from spontaneous atrial fibrillation especially in patients with coronary artery disease or in those taking antiarrhythmic drugs. The test procedure was sufficiently simple and well tolerated to be included in our routine electrophysiological investigation.     

Value of radionuclide ventriculography in the immediate characterization of patients with acute myocardial infarction

The ability of admission radionuclide ventriculography to discriminate among various clinical subsets was evaluated in patients with acute myocardial infarction. One hundred patients with acute myocardial infarction were evaluated within 8 ± 3.1 hours (mean ± standard deviation) after the onset of chest pain. Forty-one patients were in Killip functional class I, 52 in class II and 7 in class III. The mean radionuclide left ventricular ejection fraction was significantly lower in patients with higher Killip classification because of significant elevation of mean left ventricular end-systolic volume rather than significantly altered mean end-diastolic volume. Killip classification frequently failed to correlate with ejection fraction in individual cases. Admission chest X-ray findings were categorized according to the presence of findings suggestive of impaired left ventricular function. Mean left ventricular ejection fraction was significantly lower in patients with abnormal than in patients with normal chest X-ray findings because of significant elevations in both mean end-diastolic and end-systolic volumes. The chest X-ray findings frequently failed to correlate with ejection fraction in individual cases.Stepwise linear regression analysis was employed to analyze the ability of historical, physical, electrocardiographic and chest X-ray findings to predict radionuclide left ventricular ejection fraction. The most predictive variables in order of decreasing significance were anterior myocardial infarction, abnormal chest X-ray findings, rales to two thirds of the posterior thorax, previous myocardial infarction, transmural myocardial infarction and heart rate greater than 100 beats/min. However, even these six optimal predictive variables could explain only 42 percent of the observed variability in left ventricular ejection fraction. Thus, early radionuclide ventriculography adds significantly to the discriminant power of clinical and radiographic characterization of ventricular function in patients with acute myocardial infarction.     

Unstable angina pectoris. Clinical, angiographic, and myocardial scintigraphic observations.

The clinical, left ventricular and coronary angiographic data, and the technetium-99m stannous pyrophosphate (99mTc-PYP) myocardial scintigraphic results are presented in 31 patients with unstable angina pectoris. One-third of these patients had positive 99mTc-PYP myocardial scintigrams in a pattern suggesting limited and diffuse subendocardial necrosis. The positive 99mTc-PYP myocardial scintigrams occurred without diagnostic electrocardiographic and cardiac enzyme changes suggestive of myocardial infarction; positive scintigrams seemed to occur more commonly in patients with continuing pain after admission and in those without previous history of myocardial infarction. The positive 99mTc-PYP myocardial scintigrams did not correctly predict coronary anatomical patterns except that positive scintigrams occurred only in patients with coronary artery disease. Neither did the positive scintigrams necessarily occur in that group of patients with the poorest ventricular function though the 2 patients with the lowest ejection fractions both had positive 99mTc-PYP myocardial scintigrams. Finally, when positive 99mTc-PYP scintigrams are the only evidence suggestive of limited subendocardial infarction in patients with unstable angina pectoris, they do not appear to have any prognostic significance in terms of longevity or response to pharmacological or surgical therapy, though the follow-up period so far is short.     

Beverage alcohol spending in Singapore: a potential development constraint?

World Health Organization sponsored studies identify Singapore as a low-level-drinking country where beverage alcohol consumption is not growing at a rapid pace. However, data for Singapore do show that from 1978 through 1986, consumer spending on beverage alcohol was on the rise, although not alarmingly. Growing spending on beverage alcohol could signal a challenge to Singapore's continuing economic development when viewed in the context of the country's emerging labor shortage and its development strategy. Beverage alcohol could become a problem due to the upward trend in spending on drinking, the emergence of a labor shortage, and the need for the largest possible pool of highly skilled workers to sustain Singapore's growth and development. Government might, therefore, look into spending on alcohol as diligently as it focuses on the consumption of tobacco and narcotics.     

Effects on the buoyant density of rabbit platelets of ADP and agents that increase the concentration of cyclic AMP

Rabbit platelets were aggregated by adenosine diphosphate (ADP), allowed to deaggregate and then separated into density subpopulations by centrifugation through discontinuous Stractan density gradients. Although ADP causes little or no release of the contents of the amine storage granules of rabbit platelets, ADP caused a decrease in platelet density as compared with control platelets subjected to the same procedures except for exposure to ADP. The density change persisted for at least four hours. The apparent size of platelets stimulated with ADP increased initially, but returned to control values during a one-hour period. A similar decrease in platelet density was observed with an albumin density gradient. Under conditions in which aggregation did not occur in response to ADP with ethylenediaminetetraacetic acid (EDTA) in the medium, little or no decrease in platelet density was observed. Agglutination with polylysine did not change platelet density. Thus, not only agents such as thrombin and plasmin that cause the release of the contents of the platelet granules decrease platelet density, but ADP also has this effect. Platelets would be exposed to all of these stimuli during thromboembolic processes, and their effect on platelets may account for the decrease in platelet density observed previously in experiments with rabbits with indwelling aortic catheters. Agents that increase the concentration of cyclic AMP (cAMP) in platelets (PGE1, adenosine, dibutyryl cAMP, forskolin, and papaverine) also decreased platelet density. This effect persisted when the platelets were washed and resuspended in fresh medium and was also demonstrable in plasma. Platelet size was gradually increased by prostaglandin E1 (PGE1) which maintains platelets in a disc shape and does not cause the release of granule contents, indicating that the decrease in platelet density caused by PGE1 may be attributable to platelet swelling.