Benzo[b]fluoranthene: tumorigenicity in strain A/J mouse lungs, DNA adducts and mutations in the Ki-ras oncogene

The polycyclic aromatic hydrocarbon benzo[b]fluoranthene (B[b]F) is a pervasive constituent of environmental combustion products. We sought to examine the lung tumorigenic activity of B[b]F in strain A/J mice, to study the relationship between formation and decay of B[b]F-DNA adducts and to examine mutations in the Ki-ras proto-oncogene in DNA from B[b]F-induced tumors. Mice were given i.p. injections of 0, 10, 50, 100 or 200 mg/kg body wt and lung adenomas were scored after 8 months. B[b]F induced significant numbers of mouse lung adenomas in a dose-related fashion, with the highest dose (200 mg/kg) yielding 6.95 adenomas/ mouse, with 100% of the mice exhibiting an adenoma. In mice given tricaprylin, the vehicle control, there were 0.60 adenomas/mouse, with 55% of the mice exhibiting an adenoma. Based on dose, B[b]F was less active than benzo[a]pyrene. DNA adducts were analyzed qualitatively and quantitatively by 32P-post-labeling in lungs of strain A/J mice 1, 3, 5, 7, 14 and 21 days after i.p. injection. Maximal levels of adduction occurred 5 days after treatment with the 200 mg/kg dose group, producing 1230 amol B[b]F-DNA adducts/microgram DNA. The major B[b]F-DNA adduct was identified by co-chromatography as trans-9, 10-dihydroxy-anti-11, 12-epoxy-5-hydroxy-9, 10, 11, 12-tetra-hydro-B[b]F-deoxyguanosine. Approximately 86% of the tumors had a mutation in codon 12 of the Ki-ras oncogene, as determined by direct DNA sequencing of PCR-amplified exon 1 and single-stranded conformation polymorphism analysis. Analysis of the Ki-ras mutation spectrum in 25 of 29 B[b]F-induced tumors revealed the predominant mutation to be a G-->T transversion in the first or second base of codon 12, congruous with the DNA adduct data. Our data are consistent with previous reports in mouse skin implicating a phenolic diol epoxide as the proximate carcinogenic form of B[b]F that binds to guanine.     

Varicocele scintigraphy: a simplified screening method for the detection of spermatic vein reflux

Forty-three men underwent varicocele scintigraphy to exclude underlying varicocele as a possible cause of decreased semen quality. The total acquisition time for each study amounted to as little as 200 seconds. In four cases retrograde blood flow was seen in the left internal spermatic vein, with subsequent clear visualization of the pampiniform plexus. In three of four of these patients, pregnancy ensued after therapeutic intervention. Seven patients showed only increased scrotal activity locally, in the absence of retrograde blood flow. The remaining 32 patients showed a normal blood flow pattern. The existence of spermatic vein reflux in varicocele-related infertility is thought to be a major factor in proper patient selection for therapeutic ligation or embolization of the internal spermatic vein. It is suggested that this simplified scintigraphic method may be useful in the detection of retrograde blood flow in patients with varicocele, especially in small or subclinical varicocele.     

Efficacy of cobalt chelates in the rabbit eye model for epithelial herpetic keratitis

STUDY OBJECTIVE: Accurate diagnosis in emergency department patients with possible myocardial ischemia is problematic. Two-dimensional echocardiography has a high sensitivity for identifying patients with myocardial infarction (MI); however, few studies have investigated its diagnostic ability when used acutely in ED patients with possible myocardial ischemia. Therefore we investigated the ability of ED echocardiography for predicting cardiac events in patients with possible myocardial ischemia. METHODS: Echocardiography was performed within 4 hours of ED presentation in 260 patients with possible myocardial ischemia, and was considered positive if there were segmental wall motion abnormalities or the ejection fraction was less than 40%. ECGs were considered abnormal if there was an ST-segment elevation or depression of greater than or equal to 1 mm, or ischemic T-wave inversion. Cardiac events included MI and revascularization. RESULTS: Of the 260 patients studied, 45 had cardiac events (23 MI, 19 percutaneous transluminal angioplasty, 3 coronary bypass surgery). The sensitivity of echocardiography for predicting cardiac events was 91% (95% confidence interval 79% to 97%]), which was significantly higher than the ECG (40% [95% CI 27% to 55%]: P < .0001), although specificity was lower (75% [95% CI 69% to 81%] versus 94% [95% CI 90% to 97%]; P < .001). Addition of the echocardiography results to baseline clinical variables and the ECG added significant incremental diagnostic value (P < .001). With use of multivariate analysis, only male gender (P < .03, odds ratio [OR] 2.4 [1.1 to 5.3]), and a positive echocardiographic finding (P < .0001, OR 24 [9 to 65]) predicted cardiac events. Excluding patients with abnormal ECGs (N = 30) did not affect sensitivity (85%) or specificity (74%) of echocardiography. CONCLUSION: Echocardiography performed in ED patients with possible myocardial ischemia identifies those who will have cardiac events, is more sensitive than the ECG, and has significant incremental value when added to baseline clinical variables and the ECG.     

Transplanted neurons alter the course of neurodegenerative disease in Lurcher mutant mice

Embryonic cerebellar, neocortical, and striatal tissues derived from NSE-LacZ transgenic mice were transplanted into the right cerebellar hemisphere of 8- to 10-day-old Lurcher or wild-type mice. Host mice survived for 30-90 days and the transplanted tissue was examined by light microscopy using Nissl staining, X-gal histochemistry, and immunohistochemistry for calcium binding protein and glutamic acid decarboxylase. Transplantation of cerebellar tissue, but not neocortical or striatal progenitors, resulted in robust infiltration of the lurcher mutant host cerebellar cortex by transgenic Purkinje neurons. Deep to the infiltrated molecular layer, the host granular layer was thicker and denser than the mutant granular layer, but transgenic cells did not contribute to the spared granular layer. The host inferior olivary complex consistently exhibited a noticeable bilateral asymmetry in Nissl-stained sections. A quantitative analysis of the olivary complex was performed in 10 90-day-old host mice. The results indicate that the left inferior olivary complex of 90-day-old host mice contained more neurons than the right inferior olive of the host mice and contained more neurons than was observed in 90-day-old Lurcher control mice. Analysis by olivary subdivision indicates that increased neuron numbers were present in all subdivisions of the host left inferior olive. These studies confirm the specific attractive effect of the mutant cerebellar cortex on transplanted Purkinje neuron progenitors and indicate that neural transplants may survive the neurodegenerative period to interact with developing host neural systems. The unilateral rescue of Lurcher inferior olivary neurons in cerebellar transplant hosts indicates that transplanted neurons may interact with diseased host neural circuits to reduce transneuronal degeneration in the course of a neurodegenerative disease.     

Mutations in the activation loop tyrosine of the oncoprotein v-Fps

Mutations were made in the activation loop tyrosine of the kinase domain of the oncoprotein v-Fps to assess the role of autophosphorylation in catalysis. Three mutant proteins, Y1073E, Y1073Q, and Y1073F, were expressed and purified as fusion proteins of glutathione-S-transferase from Escherichia coli and their catalytic properties were evaluated. Y1073E, Y1073Q, and Y1073F have k(cat) values that are reduced by 5-, 35-, and 40-fold relative to the wild-type enzyme, respectively. For all mutant enzymes, the Km values for ATP and a peptide substrate, EAEIYEAIE, are changed by 0.4-2-fold compared to the wild-type enzyme. The slopes for the plots of relative turnover versus solvent viscosity [(k(cat))eta] are 0.71 +/- 0.08, 0.10 +/- 0.06, and approximately 0 for wild type, Y1073Q, and Y1073E, respectively. These results imply that the phosphoryl transfer rate constant is reduced by 19- and 130-fold for Y1073E and Y1073Q compared to the wild-type enzyme. The dissociation constant of the substrate peptide is 1.5-2.5-fold lower for the mutants compared to wild type. The inhibition constant for EAEIFEAIE, a competitive inhibitor, is unaffected for Y1073E and raised 3-fold for Y1073Q compared to wild type. Y1073E and Y1073Q are strongly activated by free magnesium to the same extent and the apparent affinity constant for the metal is similar to that for the wild-type enzyme. The data indicate that the major role of autophosphorylation in the tyrosine kinase domain of v-Fps is to increase the rate of phosphoryl transfer without greatly affecting active-site accessibility or the local environment of the activating metal. Finally, the similar rate enhancements for phosphoryl transfer in v-Fps compared to protein kinase A [Adams et al. (1995) Biochemistry 34, 2447-2454] upon autophosphorylation suggest a conserved mechanism for communication between the activation loop and the catalytic residues of these two enzymes.     

Evaluation of low density spine software for the assessment of bone mineral density in children

Pediatric dual-energy X-ray absorptiometry spine scans often cannot be analyzed with standard software due to a failure to identify the bone edges of low density vertebrae. Low density spine (LDS) software improves bone detection compared with standard software. The objective of this study was to compare bone mineral density (BMD) measurements obtained with the standard and LDS software in 27 healthy nonobese, 32 obese, and 41 chronically ill children, ages 2-18 years. Lumbar spine (L1-L4) BMD, measured by standard analysis, ranged from 0.531-1.244 gm/cm2. Reanalysis with the LDS software resulted in a systematic increase (mean +/- SD) in estimated bone area of 17.0+/-5.0%, an increase in bone mineral content of 6.1+/-6.3%, and a mean decrease in BMD of 8.7+/-1.7% (all p < 0.001). This resulted in a mean decrease in BMD Z score of 0.7+/-0.2. Linear regression models, predicting standard BMD from LDS BMD, were fit for the three subject groups (R2 = 0.993-0.995). Small differences in slopes were detected across groups (p = 0.07); LDS BMD predicted higher standard BMD in obese subjects. In conclusion, LDS analysis resulted in a clinically significant decrease in measured BMD. The association between analysis methods was exceptionally high (R2 > 0.99), indicating that LDS BMD accurately predicts standard BMD. Although LDS BMD in obese subjects predicts higher standard BMD results than in nonobese subjects, the small difference is of questionable clinical significance. LDS software is a useful tool for the assessment of BMD in children.     

Effects of clozapine on use of seclusion and restraint at a state hospital

We report on an 8-year-old boy with a pattern of multiple congenital anomalies that strongly suggest DK-phocomelia syndrome. Birth findings included bilateral upper limb amelia, occipital encephalocele, agenesis of the corpus callosum, right auricular tag, scoliosis, small penis, and cryptorchidism. Dental malocclusion was observed in the follow-up. This is the first case with on 8-year follow-up report of DK-phocomelia syndrome.