Smoking and Exposure to Occupational Hazards in 8,304 Workers in Guangzhou, China

This cross-sectional study aimed to describe the pattern ofsmoking in relation to occupational hazard exposure in a workingpopulation in Guangzhou, China. In 1994, data on smoking andoccupational hazard exposure from occupational health recordsof 8,304 subjects aged 35 years or older from 47 randomly selectedfactories were studied. About 49% of the men and 55% of thewomen were exposed to dust, chemicals or other hazards. Theprevalence of smoking was 56.1% in men and in women. The prevalenceof smoking in men was higher in those who were younger, withprimary education or who were workers. In women, those who wereolder, with primary education or in management jobs had highersmoking prevalence. In men and women, subjects who were exposedto occupational hazards had higher smoking prevalence: the highest(71.6%) was found in male workers exposed to dust. Urgent tobaccocontrol measures are needed to prevent the epidemic of smoking-relatedand occupation-related diseases in the workplace in China.     

Another CT sign of sinonasal polyposis: truncation of the bony middle turbinate

In order to study the features of sinonasal polyposis (SNP) on CT, 100 consecutive coronasal sinus CT examinations done for chronic inflamamtory sinonasal disease were reviewed. The CT findings of the 27 fully documented SNPs were analyzed. All our SNPs were bilateral. There was a strong tendency for extensive involvement. Nasal polyps were seen in 22 of 27 (81%); bony trabecular deossification in 23 of 27 (85%); widening of infundibulum in 26 of 27(96%). We discovered a new sign truncation of the bony middle turbinate, where the bulbous part of bony middle turbinate was missing, in 51 of 26 (58 %) of SNP patients without a previous history of middle turbinectomy, 12 of 15(80%) were bilateral. The one SNP patient (1 of 27) with previous middle turbinectomy was not regarded to be real truncation. Truncation of the bony middle turbinate is a characteristic and easily recognizable ancillary sign, and is not seen in other patterns of sinusitis. Together with other features on coronal sinus CT, this adds diagnostic confidence in diagnosing sinonasal polyposis. Correspondence to: E. Y. Liang     

Role of mesenchymal-epithelial interactions in mammary gland development

The mammary gland is a hormone-target organ derived from epidermis and develops as a result of reciprocal mesenchymal-epithelial interactions. The induction of mammary differentiation from indifferent epidermal cells by mammary mesenchyme implies induction of the complement of hormone receptors characteristic of normal mammary epithelium in cells of the epidermis. Considering the facts that mammary epithelial differentiation is induced by mammary mesenchyme and that certain aspects of hormone response (androgen-induced mammary regression) are inextricably linked to mesenchymal-epithelial interactions, it is evident that the biology of the mammary gland arises from and is maintained via cell-cell interactions. As a corollary, perturbation of stromal-epithelial interactions in adulthood may play a role in mammary carcinogenesis and in turn may provide opportunities for differentiation therapy.     

Concordant childhood acute lymphoblastic leukemia in monozygotic twins

Two 4-year-old monozygotic Chinese, female twins developed concordant childhood acute lymphoblastic leukemia (ALL) within an interval of about 2 weeks. Based on morphology and cytochemistry findings of the bone marrow blast cells, a diagnosis of ALL, L1 was made. Immunophenotyping showed the blast cells of both twins expressed similar antigens, i.e. HLA-DR, CD10, CD13, CD19, CD22 and CD34. Identical blood group, same HLA (human leucocyte antigen) genotype, sex and similar appearance suggest that the twins are monozygotic. Since the bone marrow leukemic cells of both twins were identical in morphology and expressed the same antigens with almost similar percentages of positivity, it is likely that the blast cells were derived from the same single clone. Based on the single clone hypothesis, the leukemogenic event must have arisen in utero in one twin and the cells from the abnormal clone then spread to the other twin via shared placental anastomoses.     

Retrograde pulmonary arteriography

We performed retrograde pulmonary arteriography by means of a pulmonary venous wedge injection in 10 patients with no demonstrable intrapericardial pulmonary arteries by "conventional" angiographic techniques. In all cases but one, the procedure demonstrated the feasibility of a further operation. No complications were observed. Retrograde pulmonary arteriography is an important additional method for determining the existence of surgically accessible pulmonary arteries when other techniques have failed.     

Surgical stimulation does not enhance ventilatory chemoreflexes during enflurane anaesthesia in man

To assess the impact of surgical stimulation on regulation of ventilation in anaesthetized man, we measured ventilation and the ventilatory responses to either hyperoxic hypercapnia or to isocapnic hypoxaemia in fifteen subjects anaesthetized with enflurane 1.1 MAC, just prior to and then during a surgical procedure. Anaesthesia alone reduced ventilation, increased Pa_co2 decreased the response to carbon dioxide and virtually abolished the response to hypoxaemia. The addition of operation at the same level of anaesthesia augmented ventilation and reduced Pa_co2 but did not improve the anaesthesia-induced impairment of the responses to hypercarbia and hypoxaemia. Over the range of PCO₂ and PO₂, values studied, the effects of surgery were constant and independent of chemical drive. A.M. Lam, M.D., Resident; J.L. Clement, R.N.; R.L. Knill, M.D., F.R.C.P.(C), Associate Professor; Department of Anaesthesia, University Hospital, University of Western Ontario, London, Canada. This work was supported by the Medical Research Council of Canada, Development Grant 150. Address reprint requests to Dr. R.L. Knill, Department of Anaesthesia, University Hospital, 339 Windermere Road, London, Ontario, Canada, N6A 5A5.     

Resistance to hepatotoxins acquired by hepatocytes during liver regeneration

The appearance of resistance to a number of hepatotoxins in primary cultures of hepatocytes prepared at various time intervals up to 2 weeks after partial hepatectomy is the major focus in this study. Resistance to the cytocidal effect of aflatoxin B1, 2-acetylaminofluorene, N-hydroxy-2-acetylaminofluorene, methotrexate, or methyl methanesulfonate shows a progressive increase until 48 hr and then returns to the resting level of susceptibility by 2 weeks. The genesis of mutagens from 2-acetylaminofluorene and aflatoxin B1 by S-9 liver fractions shows a decrease from and return to control values after partial hepatectomy that parallels the resistance. The levels of total cellular cytochromes P-450 also decrease following partial hepatectomy and remain from 28 to 36% less than those of controls for at least 1 week. The glutathione and total soluble sulfhydryl ("glutathione") content increase following partial hepatectomy, and the pattern is consistent with a partial role for glutathione in the resistance phenomenon as it relates to 2-acetylaminofluorene. The possible relationship between resistance to the cytocidal effects in vitro and the resistance to inhibition of cell proliferation in vivo during liver carcinogenesis is discussed.     

Phase I and pharmacologic evaluation of intraperitoneal 5-fluoro-2′-deoxyuridine

Summary Intraperitoneal (i.p.) 5-fluoro-2-deoxyuridine (Floxuridine, FUdR, FdUrd) was evaluated in a phase I study at a starting level of 500 mg given on 1 day in 2 I 1.5% dialysate. Escalations within patients were allowed every other cycle. A total of 23 patients (age, 32–78 years) received 108 treatment courses. Local tolerance at all dose levels was excellent, with no cases of drug-related peritonitis being observed. Nausea and vomiting increased in severity in relation to dose and was universal at >3,000 mg ×3 days. One patient each developed grade 1 mucositis as well as diarrhea at a dose of 3,000 mg×3 days and leukopenia and thrombocytopenia at 5,000 mg×3 days. Peritoneal fluid (PF) and plasma (PL) FdUrd profiles were monitored by an HPLC method in 13 subjects, with 7 being studied serially at 2–4 increment doses for up to 6 h. Profiles that exhibited apparent linear pharmacokinetics gave PF drug levels 2–4 logs higher than the PL counterparts, with the latter essentially declining in parallel to the former, indicating that the disposition of FdUrd from the peritoneal compartment is rate-determining. The mean terminal half-life for PF FdUrd was found to be 115 min and mean peritoneal clearance was 25 ml/min. The vast differences in drug levels and AUC found between the PF and the PL profiles suggests a high systemic clearance of FdUrd, which was confirmed in two patients receiving 2 g FdUrd by short i.v. infusion. A disproportionate increase in the plasma FdUrd levels and the corresponding AUC values was found with increasing dose, suggesting a disproportionate increase in the systemic partitioning of FdUrd when doses were escalated within a patient. Substantial levels of peritoneal 5-fluorouracil (FUra) were also detected in most of the subjects. Thus, FdUrd was found to have several desirable properties for i.p. administration: (1) a 2- to 4-log pharmacologic advantage, (2) the absence of local toxicities, and (3) a favorable antitumor spectrum and some evidence of antitumor effects in this phase I and pharmacology study. A 3,000-mg dose given in 2 l 1.5% dialysate for 3 consecutive days exhibited antitumor activity and produced no systemic toxicity except nausea and vomiting, which was controlled by antiemetics. This dose schedule is therefore recommended for phase II trials directed against small-volume disease in the peritoneal cavity, such as may be found in some stages of ovarian and gastrointestinal cancers. In addition, it is suitable for further exploration as a part of regimens including systemic therapy or drugs that modulate the action of fluoropyrimidines.Supported in part by Cancer Center Core Grant CA 14089, by ROI CA 50 412, by an ACS Institutional Grant (IN21Z, to C. R.) and by the Italian-American Foundation award (to N. C.)Deceased     

Comparative pharmacokinetics of propofol in Chinese adults and children.

The pharmacokinetics of propofol were studied in 14 healthy young male Chinese adults, aged 18-38 years, undergoing minor orthopedic surgery. All patients who received a single bolus dose of propofol 2.5 mg/kg were paralyzed with atracurium and mechanically ventilated. Anesthesia was maintained with 67% nitrous oxide plus 1-2% isoflurane in oxygen with alfentanil 5 micrograms/kg intravenously as a bolus injection. Blood concentrations of propofol over the subsequent 24 hours were measured using high pressure liquid chromatography with fluorimetric detection. Data were consistently described by a three compartment model but analysis revealed two significantly different blood propofol concentration-time profiles (p less than 0.05). Five patients, designated "fast" metabolizers, demonstrated a mean elimination half-life which was shorter than that described in Chinese children, while their total body clearance was similar. Nine other patients, designated "slow" metabolizers, had a longer mean elimination half-life and slower total body clearance than those in elderly Caucasian patients. This may be suggestive of propofol metabolism at some extra-hepatic site in some patients, while other patients demonstrate marked lipophilicitic constraint of the drug by the deep compartment.