A computerized X-ray dose-monitoring system

An x-ray dose-monitoring system using a small digital computer is described. Initially, and for every 6 months afterward, the system is calibrated using an exposure meter. For each exposure, the computer receives values of x-ray technique and beam geometry from the x-ray generator through a specially designed electronic interface. Then, by means of calibration data, entrance exposure, area exposure product, and integral dose are obtained and printed for each patient examined. The overall accuracy of the system is better than +/- 20%. Operation is semiautomatic, requiring minimum operator intervention. Over 2,000 patients have been monitored with the device. Because the system is computer-based, it offers the opportunity for statistical analysis of the data base created, as the results for each patient are stored on computer disk.     

Human GM-CSF primes neutrophils for enhanced oxidative metabolism in response to the major physiological chemoattractants

Granulocyte-macrophage colony-stimulating factor (GM-CSF) is a T cell- derived lymphokine which induces hematopoietic precursor cells to proliferate in vitro and differentiate to neutrophils and macrophages. GM-CSF also inhibits the motility of mature neutrophils (NIF-T activity), and primes neutrophils to enhance oxidative metabolism in response to the bacterial chemoattractant, N-formyl-methionyl-leucyl- phenylalanine (f-MLP). The present study was designed to determine whether this lymphokine also enhances neutrophil oxidative metabolism in response to the other major physiological chemoattractants which include complement-derived C5a, and the 5-lipoxygenation product of arachidonic acid, leukotriene B4 (LTB4). Superoxide anion production was measured as superoxide dismutase-inhibitable cytochrome C reduction. Purified biosynthetic GM-CSF enhanced superoxide anion production by neutrophils in response to f-MLP, C5a desArg, and LTB4. In contrast to several other factors which prime neutrophils, GM-CSF did not prime for an enhanced oxidative response to phorbol myristate acetate (PMA). These results suggest that GM-CSF may be an endogenous regulator of neutrophil inflammatory responses induced by the major physiological chemoattractants.     

B-lymphocytic hairy cells contain no HTLV-II DNA sequences

HTLV-II has been found in some cases of the rare T-cell form of hairy- cell leukemia (HCL) and in a leukopenic chronic T-cell leukemia mimicking HCL. We asked whether the virus is implicated in the more frequent B-cell form of HCL. DNA extracted from the mononuclear cells derived from spleen (eight cases) or peripheral blood (eight cases) of 16 patients with the B-cell form of HCL was probed. No viral sequences were detected at levels of sensitivity as low as one viral genome in five cells. Therefore HTLV-II may not be involved in the B-cell form of HCL.     

Metabolism of carcinogenic heterocyclic and aromatic amines by recombinant human cytochrome P450 enzymes

The N-hydroxylation of carcinogenic arylamines represents an initial step in their metabolic activation. Animal studies have shown that this reaction is catalyzed by the cytochrome P450 (P450) enzymes P450 1A1 and P450 1A2. In this study, utilizing enzymes expressed in Escherichia coli (and purified) or in human B-lymphoblastoid cells, the catalytic activities of recombinant human P450 1A1, P450 1A2, and P450 3A4 for N- hydroxylation of several carcinogenic arylamines were determined. P450 1A2 from both expression systems catalyzed the N-hydroxylation of 4- aminobiphenyl and the heterocyclic amines, 2-amino-3-methylimidazo[4,5- f/quinoline (IQ), 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx), and 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP). Rates were similar, with values of 1.1-7.8 nmol/min/nmol P450. In contrast, P450 1A1 catalyzed N-hydroxylation of only PhIP, and no activity was observed with P450 3A4. Further kinetic analysis with purified P450 1A2 showed similar Km and Vmax values for N-hydroxylation of the arylamines. Furafylline and fluvoxamine, inhibitors of P450 1A2 activity in human liver microsomes, were found to be inhibitory of the recombinant P450 1A2 N-hydroxylation activity. Results from this study are supportive of a major role for human P450 1A2 in the metabolic activation of arylamines.      

Replantation of digits or hands followed by destructive joint disease

The clinical records and radiographs of 45 patients who had undergone replantation of a total hand, or a part thereof, were reviewed in order to determine the prevalence and the type of articular changes occurring distal to the site of anastomoses. In three patients, destructive joint changes were observed, consisting of bony fragmentation, spiculation, and cystic or erosive lesions. These changes, which developed between five and ten months after replantation, are most likely neuropathic or osteonecrotic in pathogenesis.     

Cholangiocarcinoma complicating primary sclerosing cholangitis: cholangiographic appearances

Cholangiograms from 104 patients (and serial cholangiograms in 66 patients) with primary sclerosing cholangitis (PSC) were reviewed. In 13 patients the additional diagnosis of cholangiocarcinoma was made at biopsy or autopsy. Cholangiograms from patients with both PSC and carcinoma were compared with cholangiograms from patients with PSC alone. Marked dilatation of ducts or ductal segments (100% vs. 24%) and the appearance of a polypoid mass (46% vs. 7%) were common findings in the group of patients whose disease was complicated by malignancy. In the malignant group, polypoid masses were larger, measuring 1 cm or greater in diameter. On serial cholangiograms, four of 15 patients with progressive stricture formation and four of five with progressive ductal dilatation proved to have carcinomas. The frequent occurrence of bile duct carcinoma as a complication of PSC in this group of patients indicates that PSC has a strong tendency to undergo malignant degeneration. Cholangiographic findings which suggest malignant degeneration include markedly dilated ducts or ductal segments, presence of a polypoid mass 1 cm or greater in diameter, and progressive stricture formation or ductal dilatation.