Allylmercapturic acid as urinary biomarker of human exposure to allyl chloride

OBJECTIVE: To evaluate the use of urinary mercapturic acids as a biomarker of human exposure to allyl chloride (3-chloropropene) (AC). During three regular shut down periods in a production factory for AC, both types of variables were measured in 136 workers involved in maintenance operations. METHODS: Potential airborne exposure to AC was measured by personal air monitoring in the breathing zone. In total 205 workshifts were evaluated. During 99 workshifts no respiratory protection equipment was used. Mercapturic acid metabolites were measured in urinary extracts by gas chromatography-mass spectrometry (GC-MS). RESULTS: During 86 work shifts when no respiratory protection was used the air concentrations of AC were below the Dutch eight hour time weighted average (8 h-TWA) occupational exposure limit (OEL) of AC (3 mg/m3), whereas in 13 workshifts the potential exposure, as measured by personal air monitoring, exceeded the OEL (3.3 to 17 mg/m3). With the aid of GC-MS, 3-hydroxypropylmercapturic acid (HPMA) was identified as a minor and allylmercapturic acid (ALMA) as a major metabolite of AC in urine samples from the maintenance workers exposed to AC. The concentrations of ALMA excreted were in a range from < 25 micrograms/l (detection limit) to 3550 micrograms/l. The increases in urinary ALMA concentrations during the workshifts correlated well with the 8h-TWA air concentrations of AC (r = 0.816, P = 0.0001, n = 39). Based on this correlation, for AC a biological exposure index (BEI) of 352 micrograms ALMA/g creatinine during an eight hour workshift is proposed. In some urine samples unexpectedly high concentrations of ALMA were found. Some of these could definitely be attributed to dermal exposure to AC. In other cases garlic consumption was identified as a confounding factor. CONCLUSION: The mercapturic acid ALMA was identified in urine of workers occupationally exposed to airborne AC and the increase in ALMA concentrations in urine during a workshift correlated well with the 8 h-TWA exposure to AC. Garlic consumption, but not smoking, is a potential confounding factor for this biomarker of human exposure to AC.     

Evoked potential alterations in methylmercury chloride toxicity

The present study was designed to assess the sensitivity of evoked potential techniques to detect alterations in offspring exposed to methylmercury chloride (MMC) at different developmental periods. Recordings were obtained from the visual cortex (VEP) and lateral geniculate (LGP) in 30-day old offspring. Results revealed decreased VEP latencies for peaks N1, P1, and P2 in offspring from mothers exposed either during gestation, or nursing and in offspring exposed directly to MMC for 9 days after weaning. Although not significant, a similar trend was observed in the LPG. It is suggested that the decreased latencies may be a result of compressed brain development.     

Toxicity of methylmercury chloride in rats. III. Long-term toxicity study

In the range-finding test, 6 groups of 4 male and 4 female weanling rats were given dietary levels of 0, 0.1,0.5, 2.5, 12.5 and 250 ppm methylmercury chloride (MeHgCl) for 2 weeks. Signs of central nervous system toxicity, weight loss and high mortality appeared at 250 ppm but not at lower levels. No haematological changes were observed at 0.1-12.5 ppm. The relative weights of the liver in females on 2.5 and 12.5 ppm and of the kidneys in females on 12.5 ppm were significantly increased; the effects in males were less marked. Total mercury concentration in the kidneys increased proportionally with increasing dietary levels of MeHgCl. In the short-term test, 5 groups of 15 male and 10 female weanling rats were given dietary levels of 0, 0.1, 0.5, 2.5 and 25 ppm MeHgCl for 12 weeks. Toxic signs, weight loss and restricted food intake were observed at 25 ppm starting from week 9 onwards. Haematological, serum enzyme and urinalysis changes were seen at 25 ppm. Liver microsomal enzyme activity was increased non-significantly and liver glycogen was depressed at 25 ppm. Organ weight changes were evident at 25 ppm and histological changes seen in the spleen, kidneys, brain, spinal cord and peripheral nerves were confined to the 25 ppm level. Histochemical changes in kidney enzymes occured at 2.5 and 25 ppm. Hg concentrations in blood, hair, kidneys, liver and brain were higher at 12 weeks than 6 weeks and generally increased with increasing MeHgCl level in the diet.     

Testicular cancer

The following article provides a comprehensive review of male germ cell tumors; the pathology and the clinical manifestations of the tumors are discussed, as are the modern concepts of clinical staging. Patients with bulky stage II and stage III non-seminomatous germ cell tumors are treated with chemotherapy. The new international classification system has provided a very useful way to categorize these patients by prognosis. Patients with good- or intermediate-risk tumors may be treated with 3 courses of cisplatin, etoposide, and bleomycin (BEP) or 4 courses of etoposide and cisplatin (EP), and more than 90% of these patients will survive. Randomized trials have shown that, if only 3 courses of chemotherapy are to be given, the substitution of carboplatin for cisplatin and the omission of bleomycin are deleterious to outcome. Patients who still have a significant residual mass and normal markers after treatment should undergo a surgical resection of the residual tumor. Patients who are classified by the international classification system as having poor-risk tumors have about a 50% likelihood of survival, and many of these patients will require surgical resection of a residual tumor after chemotherapy. No randomized trial has proved a regimen to be superior to that of 4 courses of BEP. Currently, an ongoing trial is evaluating the effect of the early use of high-dose therapy in combination with hematopoietic rescue in patients with these types of tumors. Patients with small-volume stage II tumors are generally treated with retroperitoneal lymph node dissection (RPLND). About 25% of the patients selected for this procedure will actually have pathologically negative nodes. Those with positive nodes may elect to receive adjuvant chemotherapy (2 courses of BEP), which will almost always prevent relapse. An alternate approach for patients willing to comply with monthly follow-up is surveillance, with chemotherapy deferred until relapse is noted. About 50% of these patients will be cured with surgery (as many as 75% have microscopic disease only). With careful follow-up, those destined to relapse can be treated promptly and at a time when they have small-volume tumors and an excellent prognosis if they go on to receive chemotherapy. Patients with clinical stage I nonseminomatous germ cell tumors may also undergo RPLND, although an acceptable alternative for these patients is surveillance. The advantages and the disadvantages of each approach are discussed. The overall risk of recurrence is about 30%, but there have been patient groups defined that may vary in risk from 10% to 15% up to 50% or more. Patients with advanced seminoma are treated with chemotherapy. When this procedure is used, outcomes are favorable and all patients are either in good- or intermediate-risk groups, according to the international classification system. Patients with small-volume stage II tumors are treated with radiotherapy. Radiation is also generally used for the treatment of clinical stage I patients, although surveillance is growing in prominence as a means to treat these patients. Late effects of treatment are also discussed in this article. Ejaculatory function can be preserved in most patients who have early stage tumors and who undergo RPLND and in some patients who undergo surgery after chemotherapy. The most troubling effect of chemotherapy is the development of etoposide-induced leukemia, a unique--and fortunately rare--clinical entity.     

硼酚醛树脂的固化动力学研究

利用红外光谱仪研究了硼酚醛树脂在固化过程中的结构变化情况;采用差示扫描量热仪分析了硼酚醛树脂在不同升温速率下的固化行为,并运用Kissinger法对其固化动力学进行了研究,得到了固化反应活化能.结果表明:硼酚醛树脂在固化过程中,内部的活化点与固化剂发生反应,树脂的结构变化不大.与纯酚醛树脂相比,硼酚醛树脂固化温度较低,而固化反应所需活化能较高,硼的加入降低了树脂的固化反应速率.     

Testicular tumors. Echographic findings

OBJECTIVES: To analyze the sensitivity and specificity of high resolution ultrasound in testicular tumors. METHODS: The study comprised 18 histologically confirmed testicular tumors. Patient ages ranged from 19 to 79 years (mean 41). The ultrasound and the anatomopathological findings were compared. RESULTS: 12 of 18 were primary testicular tumors: 5 classical seminomas, 1 spermatocytic seminoma, 1 anaplastic seminoma, 3 embryonary carcinoma, 1 mixed teratoma and 1 immature teratoma. Ultrasound detected all tumors, accounting for a sensitivity of 100%. All tumors were hypoechoic. Substantial differences were observed between the classical seminomas and the other tumor types: the echo structure was homogeneous in 60% of the classical seminomas vs 50% for the other tumor types; 80% of the former and none of the other tumor types had well- or partially well-defined tumor margins; and finally, cystic or hyperechoic areas were not observed in the classical seminomas but in 30% of the other tumors. CONCLUSION: High resolution ultrasound should be performed if testicular tumor is suspected. This technique will confirm or discard this condition and, furthermore, if the ultrasound findings show a solid, hypoechoic lesion, regardless of the degree of definition of the tumor margins, with no cystic or hyperechoic areas, a presumptive diagnosis of classical seminoma can be made.     

隐睾下降固定术后睾丸恶变临床分析

Objective: We summarized the relationship between the descent of a testicle into the scrotum and testicular cancer. Methods: Twenty-eight patients with testicular cancer after surgical treatment of cryptorchidism were retrospective analysis. Results:All patients were performed surgical treatment of cryptorchidism from 2 to 28 years old (median, 12 years;average, 16 years). Testicular cancer age ranged from 19 to 53 years (median, 33 years; average, 36 years). Malignant transformation occurred from 3 to 25 years of operation time (average, 18 years). Twenty-seven cases of malignant cryptorchidism ipsilateral, contralateral malignancy in 1 case, 27 cases were underwent radical resection of testicular cancer. Pathology diagnosis was mainly seminoma. Retroperitoneal lymph node dissection was done in 3 cases, 18 cases were chemotherapy and radiotherapy in 3 cases. Conclusion: The undescended testicle is the most common genital malformation in boys. When diagnosed, it should be treated as early as possible, but successful treatment appears not to lessen the risk of testicular cancer, patients must be closely monitored follow-up.     

The disposition of allyl isothiocyanate in the rat and mouse

The urine was the major route of excretion of radioactivity (50-80% of dose) following the oral administration (2.5 and 25 mg/kg body weight) of allyl[14C]isothiocyanate (AITC) to male and female Fischer 344 rats and B6C3F1 mice. Smaller amounts were found in the faeces (6-12%) and expired air (3-7%). The major difference between the two species was the greater retention of radioactivity after 4 days within rats (18-24% of dose) when compared with mice (2-5% of dose). Three radioactive components were found in the urine of mice and two in rats. The three components were inorganic thiocyanate, allylthiocarbamoylmercapturic acid and allylthiocarbamoylcysteine in mice, but no cysteine conjugate was found in rat urine. In the mouse, approximately 80% of the 14C was present in the urine as the thiocyanate ion whereas in the rat some 75% was as the mercapturate. This indicates that in the mouse, hydrolysis of AITC was the major metabolic pathway whereas in the rat glutathione conjugation was the major route. A species difference was seen in the amount of [14C]AITC-derived radioactivity present in the whole blood of rats and mice; measurable levels of radioactivity remained within rat blood for a longer time period (up to 240 hr) when compared with mice (96 hr). Examination of the urinary bladders of male and female rats following oral dosing with [14C]AITC showed a sex difference with greater amounts of [14C]AITC and/or its metabolites within the bladder tissue of male rats. This data is discussed in terms of the known species- and sex-specificity of the urinary bladder tumours, which occurred after long-term administration to male rats, but not to female rats or mice of either sex, in a carcinogenicity study conducted by the National Toxicology Program in the USA.     

Testicular infarction in a patient with epididymitis

To the authors' knowledge, this case is unique to the emergency medicine literature. Although testicular infarction from epididymitis is rare, it should be considered as a complication of severe or unresolving epididymitis. These patients should be placed on broad spectrum antibiotics, i.e., quinolones; color flow Doppler of the testes should be obtained; and urologic consultation should be considered for possible admission and surgical exploration.     

Testicular torsion before 6 hours. I

BACKGROUND: Following the crash of a Boeing 737-400 aircraft on the M1 motorway at Kegworth, near Nottingham, England, on January 8, 1989, it became apparent that a large number of pelvic and lower limb injuries had been sustained by the survivors. Had there been a fire, these injuries would have severely hindered the ability of the occupants to escape. The mechanism of pelvic and lower limb injuries in impact accidents previously has been related to flailing of the limbs and axial loading of the femur as in automobile accidents. HYPOTHESIS: A bending load is the primary mechanism of femoral fracture in an impact aircraft accident rather than an axial load. METHODS: Two methods of study have been used to investigate the impact biomechanics of the pelvis and lower limb: a) clinical review of the injuries sustained in the M1 Kegworth accident; and b) impact testing. RESULTS: A clinical review of the M1 aircrash survivors suggested that axial loading was not the primary mechanism causing femoral fractures and suggested that a bending load might be applied to the femur. Impact testing confirmed that axial loading of the femur did not appear to be significant. CONCLUSIONS: Our study suggests that in the presence of intact occupant protection systems, a femoral bending mechanism involving the front seat spar of passenger seats is a primary cause of femoral fracture in an impact aircraft accident.     

Testicular tumors: clinically relevant histological findings

Testicular germ cell neoplasms affect young men in the prime of life. Although the overwhelming majority are malignant, they are curable. In addition to the stage of the disease and the presence of serum markers, there are important pathological changes that have clinical significance. These include (1) the cell type, (2) the amount of the component, and (3) the presence or absence of vascular invasion. Pure embryonal carcinoma or embryonal carcinoma in excess of 80% in a mixed tumor and vascular/lymphatic invasion are high-risk factors as they are predictors of relapse. These factors should be recognized by the pathologist and should be taken into account by the oncologist when selecting the management of a patient with a germ cell tumor of the testis.     

Testicular torsion after 12 hours. III

To identify the risk of pet ownership (i.e., cats and dogs) for alveolar echinococcosis caused by Echinococcus multilocularis, the habits and activities of 21 patients (histologic confirmation or positive serology with corresponding evidence on an ultrasonogram, radiograph, or computed tomography scan) in Austria during the period 1967-1997 were compared with the habits and activities of 84 controls matched by sex, age, and residence. Cat ownership (odds ratio (OR) = 6.47, 95% confidence interval (CI) 1.54-27.29) and hunting (OR = 7.83, 95% CI 1.16-52.77) were independent risk factors associated with alveolar hydatid disease. The study is not in agreement with the hypothesis that eating mushrooms or certain wild berries which grow near the ground are the main risk factors for acquiring this disease. No other behavior patterns or activities studied were identified as risk factors.     

Testicular seminoma with human chorionic gonadotropin production

Testicular seminoma with elevated serum human chorionic gonadotropin level (hCG-positive seminoma) is regarded as more malignant than marker-negative seminoma, although its prognosis is still unclear. To clarify the malignant potential of seminoma with hCG production, the serum levels of the beta subunit of hCG (beta-hCG) and lactic acid dehydrogenase (LDH) were examined in 35 and 40 patients, respectively, and the immunohistochemical expression of beta-hCG examined in 45 tumors. The elevation of the LDH serum level correlated to the invasive status, metastatic status and poor outcome, while that of the serum beta-hCG level correlated only to the metastatic status. Immunohistochemical expression of beta-hCG was observed in syncytiotrophoblastic giant cells in 11 tumors and a few mononuclear seminoma cells in 36 tumors. Expression was not associated with the malignancy potential, except where the expression in mononuclear cells inversely correlated to the invasive status. These results suggest that most seminomas produce a slight amount of hCG; that an elevated hCG serum level indicates the presence of metastatic tumors and mainly reflects an increase in tumor volume but not in cellular malignancy potential; and that the LDH serum level, rather than hCG, is more useful as a prognostic indicator for patients with seminoma.