Adenosine dialdehyde and nitrous oxide induce HL-60 differentiation

Adenosine dialdehyde and nitrous oxide, specific S-adeno- sylhomocysteine hydrolase and methionine synthetase inhibitors, respectively, induced differentiation of the human promyelocytic cell line HL-60. Their effect did not appear to be mediated through changes in transmethylation or decreased S-adenosylmethionine synthesis because (1) there was little correlation between the concentrations of adenosine dialdehyde that induced differentiation and those that changed the ratio of the intracellular concentrations of S- adenosylmethionine to S-adenosylhomocysteine, and (2) inhibition of methionine adenosyltransferase by cycloleucine did not induce differentiation. The differentiation induced by adenosine dialdehyde was prevented by homocysteine and that by nitrous oxide was inversely related to the medium methionine concentration. This suggested that differentiation was secondary to decreased methionine synthesis.     

Orthotopic cardiac transplantation: evaluation with CT

As cardiac transplantation has become widely available, computed tomography (CT) of the chest has played a useful role in the examination of patients after heart transplantation. To determine anatomic features related to the procedure, the authors evaluated 59 scans in 46 patients who had undergone orthotopic cardiac transplantation. Aortic anastomosis (seen in 98% of scans) and altered spacing between the great vessels (83%) proved to be the most common and most reliable findings. Other features including atrial anastomosis, high main pulmonary artery segment, remnant superior vena cava, and cardiac reorientation were also seen. Accurate interpretation of adenopathy, mediastinal abscess, and pericardial effusion will be enhanced in these patients through a better understanding of the cardiovascular-pericardial complex, which is afforded by CT.     

Gallbladder and bile duct stones: percutaneous therapy with primary MTBE dissolution and mechanical methods

The authors describe percutaneous treatment of gallbladder or bile duct stones in 18 patients who were poor surgical candidates or in whom conventional therapy failed. Dissolution was performed in most cases with methyl tert-butyl ether (MTBE) because of its potent dissolution properties; other solvents used included monooctanoin or chelating solutions. Gallbladder stones were eliminated in 11 of 13 patients (six of seven with dissolution alone, four of four with dissolution and basket extraction, one with basket removal alone). In five patients with stones in the common bile duct (n = 3), cystic duct remnant (n = 1), and intrahepatic bile ducts (n = 1), stones were eliminated with dissolution alone in two and with dissolution plus basket extraction in one. In two patients percutaneous therapy failed due to complications (vagal hypotension with bile peritonitis and transient respiratory arrest) that occurred during catheter placement. Preliminary results suggest that MTBE is effective for dissolution of many gallbladder stones and some bile duct stones. Noncholesterol solvents and adjuvant mechanical maneuvers are valuable adjuncts to achieve complete stone elimination.     

Urographic findings in homozygous sickle cell disease

A prospective study of the renal abnormalities on excretion urography in 189 patients with homozygous sickle cell disease is presented. Demonstrable abnormalities were present in 69% but there was no correlation with symptomatology. Calyceal clubbing was the most common abnormality occurring in 39% of cases and its incidence increased with age. An unexpectedly high prevalence (23%) of papillary necrosis occurred and both sinuses and cavities were demonstrated. The reasons for this high prevalence are discussed. The urographic findings did not correlate significantly with hematological features of the disease.     

The role of estrogen in pubertal skeletal physiology: epiphyseal maturation and mineralization of the skeleton

The year 1994 is likely to be remembered by many endocrinologists as the year in which dramatic new light was shed on the role played by estrogen in human skeletal physiology. It was in 1994 that two new syndromes were described, each representing a human model in which estrogen action was lacking. The first case was a female with an aromatase defect and a resultant inability to synthesize estrogen, and the second case was a man with an estrogen receptor gene defect that resulted in a non-functioning estrogen receptor and complete estrogen resistance. By examining the phenotypes of these two individuals, we were able, for the first time, to see what pubertal skeletal changes occur in the absence of estrogen action and directly extrapolate the role of estrogen in skeletal physiology. What has become abundantly clear is that it is estrogen and not androgen that is responsible for pubertal epiphyseal maturation and skeletal mineralization