On the carcinogenic risk evaluation of diesel exhaust: benzene in airborne particles and alterations of heme metabolism in lymphocytes as markers of exposure

Diesel exhaust consists of a complex mixture of chemicals which contain known genotoxicants, one of which is benzene. Therefore the concentration of benzene may be used in the evaluation of full external exposure to diesel exhaust. Our attention is focused on the determination of the distribution of benzene between the gas and particulate phases in the breathing zone of bus-garage workers. Bus diesel engine exhaust was the main source of air pollution by benzene and particles. The particulate matter contained benzene in amounts comparable to those usually found for concentrations of carcinogenic polycyclic aromatic hydrocarbons (PAHs) and nitro-PAHs. A much lower concentration of benzene was associated with particulate matter in the winter than in the summer months. The level of benzene in the gas phase showed a dependence on the distance of workplace from the operating diesel motor. The study indicated that benzene associated with diesel exhaust particles (DEP) might be an important factor to consider when studying diesel exhaust exposure from air pollution sources. Since non-genotoxic effects may play an important role in the generation of tumors by genotoxic carcinogens, the level of heme synthesis was proposed as a biomarker of early health effect. Here we present the data on determination of 5-aminolevulinic acid (ALA) synthesis and heme formation in lymphocytes from a group of 45 bus-garage workers and an analogous data from a group of 25 unexposed subjects. The results indicate significant differences in ALA synthesis and heme formation between the exposed workers when compared to the non-exposed individuals. ALA was accumulated and ALA-synthase activity was increased in lymphocytes of garage workers. At the same time ferrochelatase activity was decreased and protoporphyrin contents were elevated. In addition the concentration of porphyrin associated with DNA was significantly increased. Thus, the measurement of some metabolites of heme synthesis in lymphocytes could be a useful biomonitoring index for the determination of a sensitive subgroup of workers who undergo the higher risk of cancer development.

Comparative studies of the graviresponses of Paramecium and Loxodes

Gravitactic protozoa offer advantages in studying how the gravity stimulus is perceived on the cellular level. By means of a slow rotating centrifuge microscope in space the acceleration thresholds for gravitaxis of Loxodes striatus and Paramecium biaurelia were determined: < or = 0.15 x g for Loxodes and 0.3 x g for Paramecium, indicating different sensitivities of these species. Neutral-buoyant densities of immobilized cells were determined using media of different densities, revealing densities of 1.03 to 1.035 g/cm3 for Loxodes and 1.04 g/cm3 to 1.045 g/cm3 for Paramecium. Behavioral studies revealed that gravitaxis of Loxodes persisted independent of the density of the medium. In contrast, negative gravitaxis of Paramecium was no longer measurable if the density of the medium approached the density of the cell. The results suggest that in the case of Loxodes gravity is perceived by an intracellular receptor and, in the case of Paramecium by its own mass via the pressure on the lower cell membrane.

Anaesthesia for phaeochromocytoma in pregnancy

PURPOSE

Phaeochromocytoma in pregnancy is a rare occurrence. Details of the anaesthetic are even more rarely reported. Our purpose is to describe our management with reference to previous reports.

CLINICAL FEATURES

A 31-yr-old woman underwent resection of a phaeochromocytoma at seven weeks gestation. Preoperative preparation included 2 mg prazosin p.o. bid and 40 mg propranolol p.o. bid. A balanced anaesthetic technique including 5 mg midazolam, 1500 micrograms alfentanil, 35 micrograms sufentanil, nitrous oxide and isoflurane was used. Blood pressure was controlled with 3.4 g magnesium and 2437 micrograms nitroglycerin. There were no episodes of hypertension intraoperatively. The patient made an uneventful recovery and delivered a normal baby at 37 wk gestation by caesarean section.

CONCLUSION

Anaesthesia for resection of a phaeochromocytoma in early pregnancy can be successfully managed with preoperative alpha and beta sympathetic blockade and a balanced anaesthetic technique using magnesium as the main intraoperative hypotensive agent.

Comparison of long-term psychological responses of women after pregnancy termination due to fetal anomalies and after perinatal loss

The objective of the study was to compare psychological responses of women following a pregnancy termination due to ultrasound-detected fetal anomalies (ultrasound group) with the psychological responses of women following a late spontaneous abortion or a perinatal death (perinatal loss group). The assessments, which were performed on four occasions in the year after the life event, included Montgomery and Asberg Depression Rating Scale, Goldberg General Health Questionnaire, Impact of Event Scale, State-Trait Anxiety Inventory and Schedule for Recent Life Events. In the acute phase, a few days after the life event, the women in the ultrasound group reported statistically significantly less depressive symptoms and less intrusion and avoidance symptoms than the perinatal loss group. No differences in psychological responses in the two groups were found at the examinations at approximately 7 weeks, 5 months or 1 year. A statistically significantly higher proportion of women in the ultrasound group reported that they had tried to become pregnant in the following year. A few subjects in each group reported persisting high psychological distress throughout the year, but only one woman fulfilled the criteria of a post-traumatic stress disorder. It is concluded that the long-term psychological stress response in women to pregnancy termination following ultrasonographic detection of fetal anomalies does not differ from the stress responses seen in women experiencing a perinatal loss.

Colonic carcinoma in two adult cystic fibrosis patients

Two adult women with cystic fibrosis (CF) who developed colonic carcinoma, both at age 31, are described. In both patients the carcinoma occurred in the midtransverse colon. The diagnosis had not been suspected, partly because of the patients' relatively young age. In case 1, the symptoms also mimicked the distal intestinal obstruction syndrome. At diagnosis she was shown to have metastases to the regional lymph nodes. In case 2, despite a long history of chronic pulmonary and sinus disorders, CF was not diagnosed until the patient was 36 years old. The incidence of gastrointestinal malignancies has been shown to be significantly increased in patients with CF. As the life expectancy of the CF population increases, vigilance for gastrointestinal cancers in CF patients is important, as illustrated by these two cases.

Pharmacokinetics of morphine and its glucuronides after intravenous infusion of morphine and morphine-6-glucuronide in healthy volunteers

Steady-state pharmacokinetics of morphine and morphine-6-glucuronide (M-6-G) after intravenous administration of either morphine or M-6-G were determined in healthy volunteers. With a dosing regimen calculated on the basis of data obtained in a first series of experiments in four subjects (morphine: intravenous loading dose of 0.24 mg/kg for 5 minutes and an intravenous infusion of 0.069 mg.kg-1.hr-1 for 4 hours; M-6-G: loading dose of 0.011 mg/kg for 5 minutes and an infusion of 0.006 mg.kg-1.hr-1 for 4 hours), it was possible to yield plasma concentrations of morphine and M-6-G in another four subjects close to predefined targeted levels (35 and 45.5 ng/ml morphine and M-6-G, respectively). This dosing regimen may be used in further pharmacodynamic studies to compare the analgesic effects of morphine and M-6-G. In addition, metabolite kinetics of M-6-G were calculated as a function of time with use of a linear systems approach to the estimation of rate and fraction of morphine glucuronidation to M-6-G.

Primary adrenal leiomyosarcoma in a man with acquired immunodeficiency syndrome (AIDS). Further evidence for an increase in smooth muscle tumors related to Epstein-Barr infection in AIDS

We report a rare primary adrenal leiomyosarcoma in a 30-year-old, human immunodeficiency virus--positive man. This is, we believe, the third documented case in the English literature of this tumor in this site, and the first to be reported in an adult male with acquired immunodeficiency syndrome. The smooth muscle origin of this tumor was apparent by routine microscopy and confirmed by positive immunostaining for smooth muscle actin. The patient is presently well and shows no evidence of recurrence 20 months after surgery. The present findings are discussed with reference to the reported rising incidence of smooth muscle tumors in human immunodeficiency virus--infected patients and the associated etiologic role of Epstein-Barr virus in the pathogenesis of these tumors.

MR imaging of adrenal masses: value of chemical-shift imaging for distinguishing adenomas from other tumors

OBJECTIVE

CT and conventional MR imaging are helpful in characterizing adrenal tumors, but a specific diagnosis is not achieved for a substantial number of lesions. Chemical-shift imaging relies on the different resonance frequencies of protons in water and triglyceride molecules and therefore may permit a more specific diagnosis of adrenal adenomas, which are known to contain abundant lipid. The purpose of this study was to evaluate the usefulness of chemical-shift MR imaging in the differentiation of adrenal adenomas from other adrenal masses.

SUBJECTS AND METHODS

Forty-one adrenal masses (17 nonhyperfunctioning adenomas, two aldosteronomas, six pheochromocytomas, one ganglioneuroma, five adrenal carcinomas, one lymphoma, seven metastases, one case of extramedullary hematopoiesis, and one leiomyosarcoma) suspected clinically or identified by sonography or CT in 38 patients were prospectively evaluated with MR imaging. Pathologic proof of diagnosis was obtained for 28 lesions, and stability on imaging follow-up (mean, 19 months) was accepted as proof of diagnosis of benign adenoma for 13 lesions. In-phase T1-weighted spin-echo sequences (500/20 [TR/TE]) and opposed-phase gradient-echo sequences (142/6.3, flip angle = 90 degrees) of the adrenal regions were applied. Quantitative analysis of signal intensity loss in the adrenal lesions relative to reference tissues (liver, muscle, and spleen) on in-phase and opposed-phase sequences was done to differentiate adenomas from nonadenomas. Region-of-interest signal intensity measurements were obtained in a standard fashion by selection of the largest possible representative sample.

RESULTS

Using liver as the reference standard, we found that mean signal intensity ratios were 0.47 (range, 0.23-0.97) for adrenal adenomas and 0.88 (range, 0.65-1.32) for nonadenomas; signal intensity ratios for two adenomas overlapped those of the nonadenomas. Using muscle as the reference standard, we found that mean signal intensity ratios were 0.44 (range, 0.22-0.66) for adrenal adenomas and 0.85 (range, 0.59-1.39) for nonadenomas; signal intensity ratios for two adenomas overlapped those of the nonadenomas. Using spleen as the reference standard, we found that mean signal intensity ratios were 0.45 (range, 0.27-0.73) for adrenal adenomas and 0.97 (range, 0.8-1.18) for nonadenomas, with no overlap. The mean signal intensity ratios were significantly different between adenomas and nonadenomas for all three reference tissues (p < .001).

CONCLUSION

Our results show that chemical-shift MR imaging is an important new technique that enables the differentiation of adrenal adenomas from other adrenal masses, reducing the need for biopsy and prolonged imaging follow-up in patients with adrenal tumors.

Malignant obstruction of the common bile duct: long-term results of Gianturco-Rosch metal stents used as initial treatment

PURPOSE

To determine how long Gianturco-Rosch metal stents remain patent when used as the initial treatment for malignant obstruction of the common bile duct.

MATERIALS AND METHODS

The patency of Gianturco-Rosch metal stents was prospectively studied in 26 patients with malignant obstructive jaundice. Biliary obstruction was caused by pancreatic carcinoma (n = 15), cholangiocarcinoma (n = 10), or metastatic lymphadenopathy (n = 1). Follow-up information was obtained every 3-4 months until death.

RESULTS

Stent insertion was successful in all patients. Stent occlusion occurred in nine patients (35%). The overall mean patency period was 39.9 weeks. Adequate biliary drainage for a minimum of 80 weeks or until death was achieved in 19 patients (73%). Life-table analysis predicted stent patency rates of 86%, 75%, and 69% at 12, 24, and 48 weeks, respectively.

CONCLUSION

These results are better than those previously reported in patients with plastic endoprostheses. The authors believe that insertion of the metal stent is the procedure of choice in patients with inoperable malignant biliary obstruction.

Opioid receptor agonist potencies of morphine and morphine-6-glucuronide in the guinea-pig ileum

It has been suggested that morphine-6-glucuronide, a major metabolite of the opioid analgesic morphine, is more potent as an analgesic than the parent drug. This finding appears not to be due to differences in affinity for opioid receptors. Therefore, in the present study the opioid receptor mediated effects of morphine and morphine-6-glucuronide were compared in vitro using electrically induced contractions of isolated guinea-pig ilea in the absence and presence of increasing concentrations of the selective opioid receptor antagonists CTAP (D-Phe-Cys-Tyr-D-Trp-Arg-Thr-Pen-Thr-NH2) (mu) and norbinaltorphimine (kappa). The results showed a similar efficacy and potency for morphine and morphine-6-glucuronide and indicated that both compounds act reversibly, mainly at mu-opioid receptors. It is concluded that morphine and its metabolite morphine-6-glucuronide are equipotent at mu-opioid receptors.

Strategic management of adrenal tumors

Adrenal tumors--large and small, symptomatic and asymptomatic, benign and malignant--are being diagnosed with increasing frequency. Patients presenting with endocrine syndromes symptomatic of adrenal tumors require meticulous, considerate history taking, thorough physical examination, and careful planning for medical management and/or surgical removal. Adrenal tumors discovered in the absence of endocrine syndromes, and which are greater than 5 cm in diameter, require careful biochemical and imaging investigation before removal, since their rate of malignancy increases with size. Adrenal masses less than 4 cm in diameter present in the absence of endocrine syndromes can, after full endocrine and imaging evaluation, be carefully observed. Even with optimal surgical/medical management, malignant disease of the adrenal glands presents a poor outcome. This paper reviews the broad management of adrenal tumors, including a personal experience with a challenging case of adrenal adenocarcinoma.

Stereoselective pharmacokinetics of methadone in beagle dogs

The pharmacokinetics of methadone were studied in beagle dogs (n = 4) following intravenous administration of the racemate (0.5 mg/kg) and of the individual (R)-(0.25 mg/kg) and (S)-enantiomers (0.25 mg/kg) using a stereospecific HPLC assay. There was no significant difference between the pharmacokinetic parameters of (R)-methadone and (S)-methadone following administration of the individual enantiomers. Stereoselective differences were evident following administration of the racemate (P values for differences in AUC and CL were 0.01 and 0.046, respectively) and the clearance of the (S)-enantiomer was increased when administered as part of the racemate (316 +/- 81 vs 487 +/- 128 ml/min, P = 0.04). The data suggest that stereoselective disposition including potential enantiomer-enantiomer interactions should be considered in pharmacokinetic-pharmacodynamic studies of (R,S)-methadone.

Urodynamic parameters in patients with slight and severe genuine stress incontinence: is the stress profile useful?

This study evaluates the usefulness of the urethral pressure profile (UPP) parameters in assessing the severity of genuine stress incontinence (GSI). Functional length (FL), maximum urethral closure pressure (MUCP), pressure transmission ratio (PTR), residual area at stress (RAS), number of patients with incontinent spikes (IS), and distribution of IS on UPP were determined in supine and standing position for 54 patients (group 1) with a 1-hour pad test < 2 g and compared with the values of 63 patients (group 2) with a 1-hour pad test > 2 g. The results were similar: FL (supine: 24 mm +/- 6/26 mm +/- 7 [P:0.2]; standing: 26 mm +/- 8/24 mm +/- 11 [P:0.5]); MUCP (supine: 51 cm H2O +/- 23/47 cm H2O +/- 20 [P:0.3]; standing: 45 cm H2O +/- 21/38 cm H2O +/- 18 [P:0.1]); and PTR (supine: 83% +/- 27/84% +/- 31 [P:0.9]; standing: 81% +/- 25 and 88% +/- 27 [P:0.3]). But the RAS was lower (supine: 502 mm2 +/- 497/246 mm2 +/- 268 [P < 0.009]; standing: 500 mm2 +/- 534/271 mm2 +/- 306 [P < 0.05]) in group 2. If the percentage of patients with IS was higher (supine: 57/93% [P < 0.001]; standing: 54/84% [P < 0.01]) in group 2, the distribution of IS over the entire FL demonstrated no differences between group 1 and 2. In conclusion, except for the RAS, standard UPP parameters cannot be considered determinant in assessing the severity of GSI.