Bone disease in primary biliary cirrhosis: Lack of association with distal renal tubular acidosis

Background and Aims: Primary biliary cirrhosis (PBC) might be complicated by osteoporosis, whose etiology remains unknown but seems to be multifactorial. Prevalence rates of 30% to 60% for distal renal tubular acidosis (DRTA) have been reported in PBC patients, generally as incomplete DRTA. Although it is undisputed that a reduced bone mineral density (BMD) is the expected outcome among patients who have been suffering from longstanding chronic metabolic acidosis, it is unclear if incomplete DRTA is also associated with metabolic bone disease in PBC patients. The present study was undertaken to compare the BMD of PBC patients with and without DRTA.
Methods: The BMD of 23 PBC patients (11 with DRTA and 12 without), all with normal clearance of creatinine, was assessed by dual energy radiograph absorptiometry. The diagnosis of DRTA was made if the urine pH was above 5.4 in all samples after the oral acid overload, showing tubular inability to acidify urine in the presence of test-induced systemic metabolic acidosis.
Results: Densitometric signs of osteoporosis were found in 82% of DRTA cases and in 83% of patients without DRTA (difference not significant). There were no significant differences in BMD measurement, T and Z scores of patients with and without DRTA.
Conclusions: The present study could not support a correlation between the presence of DRTA and the bone loss observed in PBC patients.     

Multicenter Pilot Study of a Serpentine Balloon-Expandable Stent (beStentTM): Acute Angiographic and Clinical Results

The beStent is a new stainless steel, balloon-expandable mesh stent which has a unique serpentine design. Rotation of the unique low stress junctions upon expansion leads to orthogonal locking of the wires, maximizing radial strength and assuring zero shortening. The stent has delineating gold markers which assure precise positioning. We aim to present the initial acute results in a pilot registry for stent evaluation. Two hundred eighty-four stents were used in a total of 217 patients (age 57.9 ± 3.10 years; 178 males; 39 females) in seven centers, for variable indications. Stents of 15-, 25-, and 35-mm length were used. The arteries treated were the left anterior descending (n = 112, 42%), circumflex (n = 54, 20.2%), right coronary (n = 95, 35.5%), left main (n = 1, 0.4%), and vein graft (n = 5, 1.9%). Lesion types were: A in 42 patients (16.5%); B1 in 53 patients (20.7%); B2 in 81 patients (31.8%); and C in 79 patients (31%). One hundred fifty-nine patients required one stent, 40 patients required two stents, and 18 patients required three or more stents. Anticoagulation protocol included procedural heparin with aspirin with/without ticlopidine. Smooth angiographie results were obtained in all cases with no plaque herniation. Acute angiographic success was obtained in 97% of the patients, and acute clinical success in 95% of the patients. Complications within 30 days were: 3 deaths (1.4%) (2 noncardiac); 2 (0.9%) myocardial infarctions; and 2 (0.9%) stent thromboses. Therefore, the beStent is useful in treatment of complex lesions of variable length and complexity, providing excellent acute results with a low complication rate, in spite of unfavorable basic clinical and angiographie characteristics.     

ESBRA-NORDMANN 1996 AWARD LECTURE: ETHANOL DRINKING BEHAVIOUR IN SARDINIAN ALCOHOL-PREFERRING RATS

Sardinian alcohol-preferring (sP) rats have been selectivelybred for high ethanol preference and consumption over 16 yearsand 39 generations. The present paper briefly reviews some recentstudies from this laboratory characterizing ethanol drinkingbehaviour in this rat line. Under the two-bottle regimen offree choice between 10% (v/v) ethanol and water, sP rats consumedaily >4 g of ethanol/kg and avoid water almost completely.Relevant features of ethanol drinking behaviour in sP rats are:(a) attainment of high ethanol intake from the first day ofexposure to ethanol, suggestive of an immediate disclosure andacquisition of ethanol reinforcement; (b) titration of dailyethanol intake in distinct binges during the nocturnal phaseof the light/dark cycle, indicative of their ability to regularizeboth ethanol dose and administration time; (c) achievement ofpharmacologically relevant blood ethanol levels at each drinkingepisode; (d) substitution of the calories provided by ethanolfor a part of those taken from food; (e) maintenance of constantethanol intake (in g/kg/day) in the presence of ethanol concentrationsvarying from 7 to 30% (v/v). These results suggest that voluntaryethanol intake in sP rats is sustained by the search for specificpharmacological effects of ethanol. Anxiolysis is likely tobe one of these effects; indeed, voluntarily consumed ethanolreversed the innate, high levels of anxiety in sP rats. Theseresults portray sP rats as a valid model for investigating theassociation between ethanol drinking and anxiety. Finally, thebreeding programme as well as results of neurochemical studiesare also described.     

The Cardiac Pacemaker Current if

Pacemaker Current if. Since the hyperpolarization-activated current, if, was originally associated with the diastolic depolarization phase of action potential in the sinoatrial (SA) node in 1979, its central role in the generation and control of pacemaker activity has become increasingly clear through a series of experimental findings, some of which have substantially modified the pre-existing theories of cardiac pacemaking and its modulation by the autonomic transmitters. Thus, the pacemaker current of Purkinje fibers, formerly described as a deactivating pure potassium (K) current, was found to be in fact, like the nodal if, inward and activating on hyperpolarization. Furthermore, in SA node cells, as well as mediating rhythm acceleration induced by catecholamines, if was found to underlie the slowing effect of low acetylcholine (ACh) concentrations, in contrast with the generally accepted hypothesis that activation of a K conductance is the main process responsible for cardiac slowing. A final, atypical property of if recently demonstrated concerns the activating action exerted on if by intracellular cAMP. Unlike that on other voltage-gated, cAMP-modulated cardiac channels, this action is independent of phosphorylation and involves a direct binding of cAMP to if channels. (J Cardiovasc Electrophysiol, Vol. 3, pp. 334–344, August 1992)     

LONGEVITY AMONG ETHNIC GROUPS IN ALCOHOLIC LIVER DISEASE

As part of a multicenter V.A. Cooperative Study, 437 male veteranswith varying stages of alcoholic liver injury were followedover a 4.5 year period. Their ethnic distribution consistedof 256 Caucasians, 109 black Afro-Americans, 63 Puerto RicanHispanics, and 9 Native American Indians. Survival analysesrevealed significant differences between groups (P = 0.0002):66% of Afro-Americans were still living at 42 months; Caucasianswere intermediate with 40% survival; and only 28% of Hispanicswere alive. The number of Native American Indians enrolled wastoo small to draw conclusions but none of those enrolled survivedbeyond 24 months. Survival regression analysis of 30 clinical,laboratory, histologic and nutritional parameters, revealedthe following significant risk factors: clinical severity (P< 0.0001), histologic severity (P < 0.0001), race (P =0.001), age (P = 0.002), BUN (P = 0.01) and ALT (P = 0.02).These analyses indicated that ethnicity, independent of othervariables, is significantly associated with outcome from thedisease.