Thyroid hormone and the d-type cyclins interact in regulating enterocyte gene transcription

Thyroid hormone (T3) is an important regulator of gut mucosal development and differentiation, inducing intestinal alkaline phosphatase (IAP) and repressing lactase gene transcription. In contrast, cyclin D1 (CD1) appears to be a growth promoter in the gut, functioning to maintain the undifferentiated state. The present studies were designed to examine the effects of CD1 on T3 action within intestinal epithelia. Caco-2 cells were maintained in hypothyroid medium and transiently transfected with either rat lactase (3.0 kb) or human IAP (2.4 kb) luciferase (Luc) reporter plasmids. Cotransfections were carried out using two T3 receptor (TR) isoforms, TR"-1 and TR$-1, as well as plasmids expressing CD1, CD3, CA, or CB1. Cells were then treated +/- 10 nmol/L T3 for 24 hours and luciferase activity was determined. With T3 treatment, IAP-Luc activity was induced (TR"-1 = eightfold, TR$-1 = ninefold), but these effects were dramatically inhibited (> 50%) by CD1 and CD3. In contrast, CA and CB1 did not alter T3-mediated IAP gene activation. The ability of CD1 and CD3 to inhibit T3 action was also tested in the context of the lactase gene, which is negatively regulated by T3. As expected, lactase reporter gene activity was repressed by T3 treatment in the case of both receptor isoforms, TR"-1 = 30% and TR$-1 = 40%. In contrast to its effects on the IAP gene, CD1 did not inhibit T3-mediated changes in lactase reporter gene activity. The D-type cyclins (CD1 and CD3), but not CA or CB1, specifically inhibit T3-mediated activation of the IAP gene. In contrast, the D-type cyclins do not inhibit T3-mediated repression of the lactase gene. These studies have identified a novel molecular interaction that exists between the pathways of growth and differentiation within intestinal epithelia.

GATA family transcription factors activate lactase gene promoter in intestinal Caco-2 cells

The GATA family of transcription factors regulate tissue-specific patterns of gene expression during development. We have characterized the interaction between GATA proteins and the lactase gene promoter. Nuclear protein bound to the lactase gene GATA region cis element (-97 to -73) was analyzed by electrophoretic mobility shift assays (EMSA) and supershift assays with GATA antibodies. Lactase promoter activities were assayed in Caco-2 cells transfected with wild-type and mutated luciferase promoter-reporter constructs and GATA-4/5/6 expression constructs. EMSA with the GATA region probe yields a specific DNA-protein complex that requires the GATA factor binding site WGATAR. The complex is recognized by GATA-4- and GATA-6-specific antibodies. GATA-4/5/6 expression constructs are able to activate transcription driven by the wild-type promoter, but not by a promoter in which the GATA binding site is mutated, in Caco-2 and nonintestinal QT6 cells. GATA factor binding to the lactase cis element correlates with functional promoter activation. We conclude that each of the GATA family zinc finger proteins expressed in the intestine, GATA-4, -5, and -6, can interact with the lactase promoter GATA element and can function to activate the promoter in Caco-2 cells.

Identification of occupational cancer risks in British Columbia. A population-based case-control study of 995 incident breast cancer cases by menopausal status, controlling for confounding factors

Lifetime occupational histories as well as information on known and suspected breast cancer risk factors were collected by means of a self-administered questionnaire from 1018 women with incident breast cancer ascertained from the British Columbia Cancer Registry, and from 1020 population controls. A matched case-control study design was used. Conditional logistic regression for matched sets data and the likelihood ratio were used in a two-step procedure and were performed separately for pre-menopausal women, post-menopausal women, and for all cases combined. Excess risk was noted for several white-collar occupations. Significantly increased risk was observed: (1) among pre-menopausal women: in electronic data-processing operators; barbers and hairdressers; in sales and material processing occupations; and in the food, clothing, chemical and transportation industries; (2) among post-menopausal women: in schoolteaching; in medicine, health, and nursing occupations; in laundry and dry-cleaning occupations; and in the aircraft and automotive, including gasoline service station, industries. Several significant associations were also seen in the combined group of pre- and post-menopausal women, particularly in crop farmers and in the fruit and vegetable, publishing and printing, and motor vehicle repair industries. The results of this study suggest excess breast cancer risk in a number of occupations and industries, notably those that entail exposure to solvents and pesticides.

The homeodomain protein Cdx2 regulates lactase gene promoter activity during enterocyte differentiation

BACKGROUND & AIMS

Lactase is the intestinal disaccharidase responsible for digestion of lactose, the predominant carbohydrate in milk. Transcription of the lactase gene is activated during enterocyte differentiation. We have characterized the interaction between the lactase promoter and Cdx2, a homeodomain protein involved in regulating intestinal development and differentiation.

METHODS

Nuclear protein bound to the lactase gene cis element, CE-LPH1, was analyzed by electrophoretic mobility shift assays and supershifts with Cdx2 antibody. Lactase promoter activities were assayed in cells transfected with luciferase reporter constructs and a Cdx2 expression construct.

RESULTS

Electrophoretic mobility shift assay with CE-LPH1 yields a specific DNA/protein complex that requires the caudal-related protein binding site, TTTAC. The complex is recognized by Cdx2 antibody and is more abundant in differentiated enterocytes. A Cdx2 expression construct is able to activate transcription driven by the wild-type, but not a mutated, promoter and results in increased endogenous lactase messenger RNA.

CONCLUSIONS

The homeodomain protein Cdx2 interacts with the lactase promoter and is capable of activating transcription of the endogenous gene. In contrast to a previous report, Cdx2 interaction with the lactase promoter correlates with enterocyte differentiation. These conclusions are consistent with the role of Cdx2 in regulating intestinal cell differentiation.

Accuracy of surgeon-performed gallbladder ultrasound

BACKGROUND

Symptomatic cholelithiasis is among the most common of general surgery referrals. With an appropriate clinical presentation, definitive diagnosis requires documentation of gallstones by ultrasonography (US). The authors evaluated the accuracy of surgeon-performed US for identifying gallstones in patients with a nonacute indication for study.

METHODS

Patients referred for symptomatic cholelithiasis and who provided informed consent received an US examination by one or more of the surgical investigators. Surgeon-performed US findings were correlated with radiologist US findings and pathologic diagnoses.

RESULTS

Seventy-seven patients received a total of 128 examinations by the investigators. Surgeon-performed US examination agreed with the radiologist US findings for 112 of 122 studies (92%) with a sensitivity of 100% and a specificity of 95%. Surgeon-performed US findings correlated with the pathologic diagnoses for 83 of 86 studies (97%).

CONCLUSIONS

Surgeons can perform gallbladder US in the nonacute setting with a high degree of accuracy.

[Epidemiological survey on orchard pollinosis]

OBJECTIVE

To investigate the prevalence of Orchard Pollinosis in China.

METHOD

From 1995 to 1998, an epidemiological survey on orchard pollinosis was carried on among 1,660 primary and middle school students and 2,167 university students, including questionnaire investigation, nasal inspection and scratch test. From April to June of 1998, a clinical investigation of orchard pollinosis was adopted among 30 patients of allergic rhinitis including scratch test and nasal mucosa test.

RESULT

1. The total positive rate of orchard pollen scratch test was 6.7%, and the prevalence of orchard pollinosis was 0.37%. 2. 5 cases (16.7%) were hypersensitive to orchard pollen clinically in allergen test.

CONCLUSION

Orchard pollinosis is one kind of important pollinosis and should be paid high attention to.

[Evaluation of DNA recombinant chitinase fusion protein antigens in serological diagnosis for filariasis]

OBJECTIVE

To evaluate DNA-recombinant chitinase fusion protein antigen in serodiagnosis for Bancroft's filariasis in jirds rats with microfilaremia and normal jirds rats with ELISA, and its prospect in the market to be spread.

METHODS

Oligonucleotide was synthesized with filaria monoclonal antibody (Mf(1))-recognized microfilaria chitinase fusion protein and basic primer recognized by original clonal nucleosides, and amplified with polymerase chain reaction (PCR). PCR products were expressed in Pmal-c vector and purified by affinity chromatography. Experimental animals were inoculated with chitinase fusion protein antigen and infected with larval stage filaria Brugia malayi, respectively. Functional protein molecule of chitinase antigen was analyzed with SDS-PAGE and western blot. Serum level of specific antibody to chitinase antigen was determined by ELISA, and compared with that to microfilaria xt antigen (Mf-xt).

RESULTS

Specific function protein molecule of the above-mentioned chitinase antigen has been identified as 69,000. Serum antibody against chitinase antigen was 100% positive for jirds and patients with microfilaremia, but, that against Mf-xt only 80% positive. Serum antibody against chitinase antigen was negative for all normal jirds and normal persons, but that against Mf-xt had 5% false positive in normal serum. For those with microfilaremia from non-filariasis-prevalent areas, false sero-positivity was 5% and 20% with chitinase antigen and Mf-xt, respectively.

CONCLUSION

ELISA with DNA recombinant fusion protein antigen is a sensitive and specific method in serological diagnosis and surveillance for filariasis, with simple, easy and convenient manipulation. It can be used in field serologic surveillance and diagnosis for filariasis during the late phase in control of filariasis and can be spread in good prospects.

[The study of carbonaceous adsorbent for solid-phase microextraction and the comparison with commercial device]

The parameters governing solid-phase microextraction have been investigated, and the development of carbonaceous adsorbent for SPME is presented because it is durable and inexpensive. The time profile curves were determined for several organic pesticides having a wide range of water solubilities and the effect of salt was also investigated. The method of SPME-GC-ECD to analyse trace level of the organic pesticide in water is established by the determination of optimum parameters. The comparison with commercial SPME device shows that the carbonaceous adsorbent having been treated with physical or chemical method for SPME can get lower limits of detection than polyacrylate and polydimethylsiloxane, although there are still some work to be done to improve its precision. The results shows that this new SPME device has great application potential.

Supercritical fluid CO2 extraction of colchicine from colchicine Autumnele liliaceae

Colchicine was successfully extracted from the corms of colchicine autumnele Liliaceae using supercritical fluid (SF) CO2. The pressure range used in the experiments was 20-40 MPa and the temperature was 40 degrees C. Being its high molecular polar, colchicine or other alkaloids are not easy to be extracted by SF CO2. In order to increase the mass transfer from the sample matrix to SF, different presoakers (such as methanol, ethanol, acetone etc.) were employed. Among the selected pre-soakers, best results were obtained with ethanol both in the aspects of yield and selectivity. At 35 MPa, 40 degrees C and with ethanol as pre-soaker, the yield was 1.8 mg/g, and the colchicine could be almost completely extracted from the sample matrix. The average concentration increased from 0.18% in natural sample to 6.92% in extract with SFE processing only once under the given conditions. The comparison of liquid ethanol extraction (LEE) and SFE showed that SFE is greatly superior to LEE in colchicine separation with SFE not only higher yield and selectivity but also a quick, safe and non-toxic method were obtained in colchicine extraction.

Identification of occupational cancer risks in British Columbia. Part II: A population-based case-control study of 1516 Prostatic cancer cases

We have, as part of a program aimed at detecting occupational risk factors in British Columbia, collected lifetime occupational histories from 15,643 incident cancer cases, of whom 1519 had a diagnosis of prostate cancer. Occupational risks for this cancer site are examined using this large data set, and the results are presented in this report.

Identification of occupational cancer risks in British Columbia. Part I: Methodology, descriptive results, and analysis of cancer risks, by cigarette smoking categories of 15,463 incident cancer cases

To identify occupational cancer risk factors, lifetime occupational, smoking, and alcohol-consumption histories were collected by means of a self-administered questionnaire from 15,463 male cancer patients aged 20 years and over as ascertained from the British Columbia population-based cancer registry; all cases were histologically confirmed. The study methodology, descriptive results, and cancer risks from cigarette smoking are reported. Assessment of questionnaire validation and reliability showed very high correlations between all variables analysed. Non-response bias, assessed among 221 non-responders and 432 matched controls, revealed no statistically significant differences for smoking status, education, or for 11 usual (longest-held job) occupational groups, except for managerial occupations and for four pooled groups that represented 6.7% of all occupations. Except for pancreatic cancer, a significant relationship was found for all cancer sites known to be strongly associated with cigarette smoking.

[Construction of full-length cDNA clone and complete nucleotide sequence of RNA2 of cucumber mosaic virus SD strain]

The full-length cDNA clone of CMV-SD RNA2 was constructed from two cDNA clones, which were obtained by RT-PCR with primers synthesized based on terminal sequences determined using 5' RACE and 3' RACE, respectively; and the complete sequence was determined. It consists of 3048 nt and there are two partial overlapped ORFs. ORF1, which is located in the 5' portion (79-2652 nt), codes for 2a protein of 858aa, and GDD consensus sequence reported to be "polymerase site" was found in deduced 2a protein sequence. ORF2, which is located in the 3' portion (2414-2746 nt), codes for 2b protein of 111aa. The overall nucleotide sequence homologies with RNA2 of CMV Fny and Q strain, which are representatives of subgroups I and II, respectively, are 91.7% and 75.6%; the amino acid sequence homologies are 93.8% and 67.7% for 2a protein, and 83.0% and 51.3% for 2b protein, respectively. These results demonstrated that CMV-SD belongs to subgroup I.

Long term disability rates in a cohort of Air Canada pilots

Causes of long term disability (LTD) were collected between January 1, 1981 and December 31, 1990 among all active pilots in a cohort of Air Canada pilots. During this 10-yr period, 474 (20.9%) of the 2271 pilots had LTD; there were 1107 cases of LTD corresponding to a total duration of leave of absence of 4161 mo. Frequencies of the main diagnostic categories were: injuries: 249 (22.5%); mental disorders: 175 (15.8%); circulatory system: 157 (14.2%); digestive system: 128 (11.6%); and musculoskeletal system: 121 (10.9%). LTD rates increased with age, ranging from 1.86-9.22 per 1000 pilots per year from the younger (20-29 yr) to the older age group (50-59 yr), respectively. Several causes of LTD could be potentially preventable, in particular injuries which accounted for 63.6% of all causes in the younger age group and remained a significant condition at subsequent ages.

Identification of the catalytic glutamate in the E1 component of human pyruvate dehydrogenase

The pyruvate dehydrogenase complex catalyzes the conversion of pyruvate to acetyl-CoA. The first component (E1) converts pyruvate to bound acetaldehyde using thiamine diphosphate (ThDP) and Mg2+ as cofactors. There is no 3D structure of E1 available but those of other ThDP-dependent enzymes show some similarities including a glutamate residue that assists in ThDP activation. Eukaryotic E1 has an alpha2beta2 structure and the conserved Glu89 of the beta-subunit was identified as a possible catalytic residue by sequence alignment. Human E1 was expressed in Escherichia coli and purified. Mutating Glu89 to glutamine, aspartate and alanine markedly reduces catalytic activity and the affinity for ThDP, consistent with a role as the catalytic glutamate.

Industrial hygiene aspects of a sampling survey at a bleached-kraft pulp mill in British Columbia

To validate exposure estimates used to investigate correlations between exposure and cancer risk, 1678 personal measurements were collected for 46 job titles during 73 day shifts at a bleached-kraft pulp mill. Measurements included shift-long average and short-term exposures to carbon monoxide, chlorine dioxide (ClO2), and hydrogen sulfide; and shift-long average exposures to calcium oxide and wood dust (WD). Overall results indicate low levels of exposure with a few noteworthy exceptions. Although ClO2 was the exclusive bleaching agent, 77 area samples indicated that chlorine (Cl2), not ClO2 was present in all areas apart from the chemical preparation area (chem-prep) and during a pulp spill. The highest shift-long exposures to Cl2 were measured in the chip yard and are attributed to uncontrolled stack emissions. Finally, WD samples collected from several laborers significantly exceeded regulatory limits, with the highest exposures measured in the steam and recovery area. For short-term exposures to ClO2 in chem-prep, 12 of 17 data-logging electro-chemical sensor sample results showed at least one peak that exceeded the short-term exposure limit of 0.3 ppm. The use of data-logging equipment quantified short-term exposures that previously had been characterized only anecdotally. The peaks were correlated with tasks and upset conditions and, given their transient nature, these exceedances could not have been detected using shift-long average-based sampling devices. Since the respiratory effects of significant short-term exposures to irritant gases such as Cl2 and ClO2 are well-documented, data-logging instruments are necessary to characterize exposures in the pulp and paper industry.

Inactivation kinetics of model and relevant blood-borne viruses by treatment with sodium hydroxide and heat

To determine the efficacy of a clean-in-place system for the inactivation of viruses present in human plasma, the effect of 0.1 M sodium hydroxide at 60 degrees C on viral infectivity was investigated. Inactivation of the following model and relevant viruses were followed as a function of time: human hepatitis A virus (HAV), canine parvovirus (CPV; a model for human parvovirus B-19) pseudorabies virus (PRV, a model for hepatitis B virus), and bovine viral diarrhoea virus (BVDV, a model for hepatitis C virus and human immunodeficiency virus). Infectivity of CPV was determined by a novel in situ EIA method which will prove useful for studies to validate parvovirus inactivation or removal. Infectivity of BVDV, PRV and CPV were shown to be reproducibly inactivated below the limit of detection by 0.1 M NaOH at 60 degrees C within 30 s. HAV was inactivated to below the limit of detection within 2 min. Treatment with heat alone also resulted in some log reduction for all viruses tested except for CPV which remained unaffected after heating at 60 degrees C for 16 min. Treatment of HAV with hydroxide alone (up to 1.0 m) at 15 degrees C did not lead to rapid inactivation. Collectively, these data suggest that 0.1 M NaOH at 60 degrees C for two min should be sufficient to inactivate viruses present in process residues.

The gene 4 of rice yellow stunt rhabdovirus encodes the matrix protein

The complete nucleotide sequence of the gene 4 of rice yellow stunt rhabdovirus (RYSV) was determined from cDNAs corresponding to the viral genomic RNA. Gene 4 is 913 nucleotides (nt) long, comprising a 17-nt untranslated 5' region, a 786-nt open reading frame encoding a polypeptide with a molecular mass of 29,125 Da, and a 110-nt untranslated 3' region. Western blot analysis of the RYSV proteins using the antiserum raised against the protein expressed from the cloned gene in Escherichia coli indicates that gene 4 encodes the M protein of RYSV. Comparisons of the deduced amino acid sequence of the M protein of RYSV with those of other rhabdoviruses revealed no significant homologies. However, it shared a similar basic property and a similar distribution of charges with the other rhabdovirus matrix proteins and showed a relatively closer relationship to the sonchus yellow net virus (SYNV) M1 protein.

Lectin ingestion : changes in mucin secretion and bacterial adhesion to intestinal tissue

Phytohemagglutinin (PHA), the lectin derived from red kidney been (Phaseolus vulgarus) causes reduced growth rates in several animal species, when incorporated at 0.5-5% of dietary protein. Lectin feeding results in diarrhea, impaired nutrient absorption, growth rate inhibition, and can even lead to the eventual death of PHA-fed animals. These effects are believed to result from changes in the autochthonous microflora induced by the presence of PHA in the diet, as germ-free animals do not display the same changes seen in conventional animals (1-11) Jayne-Williams' (1,2) now classical studies in the quail clearly demonstrate this point. It is established that these adverse effects are the result of PHA-induced changes in the normal endogenous flora and are not due to lectin selection of specific pathogenic bacteria (9, 10) The major change appears in the levels of facultative aerobes, which increase in PHA-fed animals without an increase in obligate anaerobes (2,6). These observations separate the effects of PHA feeding from blind loop syndrome or other stressrelated changes in bacterial flora, in which anaerobic bacterial overgrowth is observed (12,13). Phytohemagglutinin feeding has also been observed to affect small intestinal growth (14).

Cohort mortality study of pulp and paper mill workers in British Columbia, Canada

The authors studied a cohort of 30,157 male pulp and paper workers in British Columbia, Canada. Of these, 20,373 worked in kraft mills only, 5,249 in sulfite mills only, and 4,535 in both kraft and sulfite mills. All workers with at least 1 year of employment on January 1, 1950, or thereafter until December 31, 1992, were studied. Standardized mortality ratios (SMRs) were used to compare the mortality rates of the cohort with those of the Canadian male population. Ninety percent confidence intervals (CIs) for the SMRs were obtained. Cancer risks significantly associated with work duration and time from first employment of 15 years or more were observed: 1) total cohort: pleura (SMR = 3.61, 90% CI 1.42-7.58); kidney (SMR = 1.69, 90% CI 1.13-2.43); brain (SMR = 1.51, 90% CI 1.03-2.16); 2) workers in kraft mills only: kidney (SMR = 1.92, 90% CI 1.04-3.26); 3) workers in sulfite mills only: Hodgkin's disease (SMR = 4.79, 90% CI 1.29-12.37); 4) workers ever employed in both kraft and sulfite mills: esophagus (SMR = 1.91, 90% CI 1.00-3.33). These malignancies have been associated with the following known or suspected carcinogens to which pulp and paper workers may have been exposed: asbestos (pleura), biocides (kidney), formaldehyde (kidney, brain, Hodgkin's disease), hypochlorite (esophagus). A nested case-control study with detailed exposure assessment is under way to help determine whether excess risks for specific cancers reflect exposure among subsets of workers.

[Experimental study of the mechanism on blood supply to delayed separated skin flap by ultrasonic Doppler]

In order to investigate the mechanism of blood supply to the delayed separated skin flap and the time and criteria for its transfer, 5 small-sized Banna pigs were selected to produce 14 skin flaps. In the experimental group the skin flap on one side was made from the middle of the back having an extra-thin steel sheet intervened between the flap and the soft tissue of the back whereas the flap on the opposite side without a steel sheet intervened was served as the self-control. The skin flaps were examined 3,7,10 and 20 days after the operation and 3,7 and 10 days after transfer, respectively, by (1) gross observation; (2) ultrasonic Doppler; (3) superficial skin temperature measurement and; (4) histomorphological examination. In the experimental group the survival rate of the flap was 100 percent whereas in the control group all of the flaps had necrosis from 30 to 50 percent after the flap being transfered. In the experimental group, the echo sound from the arterial blood flow from ultrasonic Doppler was heard at the pedicle 7 days after the operation, and as time elapsed, the echo sound spread distally, whereas in the controls no echo sound could be heard over the skin flap. There was significant difference statistically between the experimental and control groups in the temperature of the flaps while the flaps were being transferred (P < 0.01). The external diameters of the blood vessels in the central area of the skin flap were larger in the experimental group, 0.8 to 1.2 mm in comparison to 0.4 mm.

Induction of ferritin synthesis in human lung epithelial cells treated with crocidolite asbestos

Crocidolite asbestos is a known human carcinogen containing 27% iron by weight. It has previously been shown that iron was mobilized intracellularly from crocidolite after treatment of human lung epithelial cells (A549) and that the toxicity of the fibers was directly related to how much mobilized iron was in the < 10,000 MW (low-molecular-weight, LMW) fraction [C. C. Chao, L.G. Lund, K. R. Zinn, and A. E. Aust (1994) Arch. Biochem. Biophys. 314, 384-391]. The data here show that iron mobilization from crocidolite began immediately after treatment of the A549 cells and increased linearly with time. However, the synthesis of ferritin, an iron storage protein, did not begin until after 4 h of treatment, reaching a sustained maximum after 12 h. Mobilized iron was preferentially incorporated into the nonferritin-protein fraction up to 7 h after treatment, when the amount of iron mobilized was low and before significant accumulation of newly synthesized ferritin had occurred. This suggested that these cultured cells needed additional iron for synthesis of iron-requiring proteins and that iron mobilized from crocidolite could be utilized directly for this purpose. Subsequent to this, additional mobilized iron was incorporated into newly synthesized ferritin. Even though iron from crocidolite was incorporated into newly synthesized ferritin or into other proteins, the amount of iron from crocidolite in the LMW fraction remained constant during the 24 h. Thus, it appeared that synthesis of ferritin may not have fully protected the cells from the toxic effects of iron mobilized from crocidolite.

[Study of the photoluminescence spectra of laser dye impregnated in porous silicon]

We studied the photoluminescence (PL) of the compound films, which were made by implanting some laser dyes into the porous silicon films, and compared it with the PL of the laser dyes in other states. We also measured the PL of the compound films with different substrates. It was found that the spectra symmetry of the implanted laser dyes is better than that of the dyes in other states. The experimental results suggest that the PL of the compound films mainly comes from the monomers of the implanted laser dyes.

Selection of trypsin inhibitors in phage peptide library

The newly developed techniques of peptide libraries have become a conventional and efficient method in screening ligands of proteins of interest. We present here the successful results of selection of trypsin inhibitors in a phage hexapeptide library. After affinity selection and activity assay, peptide sequences, deduced from DNA sequencing of the phage peptides with the most striking trypsin activity, share some common features with trypsin inhibitors reported. All of the phage peptides selected out and those native and synthetic trypsin inhibitors reported are composed of three parts: (a) positively charged part (Arg, Lys or their analogs); (b) polar part that may form hydrogen bonds with Ser in the active site of trypsin; (c) hydrophobic part that interacts with the nonpolar region of trypsin active site.

Cohort study of Air Canada pilots: mortality, cancer incidence, and leukemia risk

Despite the special working environment and exposures of airline pilots, data on risk of death and cancer incidence in this occupational group are limited. The authors investigated a cohort of 2,740 Air Canada pilots who contributed 62,449 person-years of observation. All male pilots employed for at least 1 year on and since January 1, 1950, were studied. The cutoff date for outcome information was December 31, 1992. Standardized mortality ratio (SMR) and standardized incidence ratio (SIR) were used to compare mortality rates and cancer incidence rates of the cohort with the respective Canadian population rates. Ninety percent confidence intervals of the SMR and SIR were calculated. Statistically significant decreased mortality was observed for all causes (SMR = 0.63, 90% confidence interval (CI) 0.56-0.70), for all cancers (SMR = 0.61, 90% CI 0.48-0.76), and for all noncancer diseases (SMR = 0.53, 90% CI 0.45-0.62). Mortality from aircraft accidents was significantly raised (SMR = 26.57, 90% CI 19.3-35.9). Significantly decreased cancer incidence was observed for all cancers (SIR = 0.71, 90% CI 0.61-0.82), rectal cancer (SIR = 0.42, 90% CI 0.14-0.96), lung cancer (SIR = 0.28, 90% CI 0.16-0.46), and bladder cancer (SIR = 0.36, 90% CI 0.12-0.82). Prostate cancer (SIR = 1.87, 90% CI 1.38-2.49) and acute myeloid leukemia (SIR = 4.72, 90% CI 2.05-9.31) were significantly increased. The preferred relative risk model for radiation-induced nonchronic lymphoid leukemia (Beir V report) was applied to the cohort by using published estimates of in-flight radiation exposures. The estimated relative risk ranged from 1.001 to 1.06 and did not differ significantly from the observed SIR (SIR = 1.88, 90% CI 0.80-3.53). However, the incidence rate of acute myeloid leukemia was significantly increased. Monitoring of in-flight radiation exposure and long-term follow-up of civil aviation crew members is needed to further assess cancer incidence and leukemia risk in this special occupational group.

Injectable testosterone undecanoate has more favourable pharmacokinetics and pharmacodynamics than testosterone enanthate

Testosterone preparations producing constant physiological testosterone serum levels are desirable for long-term treatment of androgen deficiency. However, all injectable testosterone esters used clinically for substitution of male hypogonadism are characterized by unfavourable pharmacokinetics. We therefore tested two groups of five long-term orchidectomized cynomolgus monkeys (Macaca fascicularis), which received a single intramuscular injection of 10 mg/kg body weight of an injectable testosterone undecanoate (TU) preparation or testosterone enanthate (TE) in a preclinical study to assess the pharmacokinetic and pharmacodynamic characteristics of TU in comparison to TE. The dose was equivalent to 6.3 and 7.2 mg of pure testosterone per kilogram body weight in the TU and TE group, respectively. Following injection of TU, mean serum testosterone rose to 58 +/- 18 nmol/l on day 1 and remained at moderately supraphysiological levels of 40-68 nmol/l for 45 days. Thereafter, testosterone levels were maintained in the normal range of intact monkeys for another 56 days. The TE injection resulted in highly supraphysiological levels of 100-177 nmol/l from immediately after the injection to day 5. A rapid decline followed and testosterone levels reached the lower limit of normal after 31 days. Serum testosterone levels were significantly higher in the TE-than in the TU-treated animals on days 0.5-7 (p < 0.05). Significantly lower testosterone levels were seen in the TE than in the TU group on days 16, 22, 25 and 31 (p < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Characterization of quail intestinal mucin as a ligand for endogenous quail lectin

The S-type lectins have been shown to be components of mucosal scrapings, and in avian systems these lectins have been localized immunohistochemically to the mucosal surface and goblet cells of the intestine. The interaction of lectin specifically with purified mucin has not, however, been established. Quail intestinal mucin was purified by two subsequent isopycnic density-gradient centrifugations in CsCl and chromatography on Sepharose Cl-2B. Purified mucin, obtained from the void volume of the Sepharose column, was characterized by SDS/PAGE, amino acid and carbohydrate analyses, sensitivity to thiol reduction, and cross-reactivity with antibody preparations to rat and human intestinal mucins on Western blots. Antibody raised against purified quail mucin partially cross-reacts with purified rat, rabbit and human intestinal mucins, and specifically labels the mucosal surface and goblet cells of quail intestine by the immunoperoxidase technique. Protein eluted by lactose from an affinity matrix composed of quail intestinal mucin possessed the same molecular mass on SDS/PAGE as intestinal lectin and reacted on Western blots with a lectin-specific antibody. The data clearly demonstrate the co-localization of lectin and mucin in the quail intestine and also the ability of the lectin to specifically interact with the purified mucin, raising the question of the role of endogenous lectins in secretions.

Use of dengue blot in dengue diagnosis: the Malaysian experience

Dengue fever/Dengue haemorrhagic fever (DF/DHF) has been a public health problem in Malaysia with an endemic level of about 7 per 100,000 population per year. In 1990, Malaysia experienced its most severe outbreak of DF/DHF with a record total of 5,590 cases referred to the Division of Virology, Institute for Medical Research (IMR). Of these, 1,880 were confirmed serologically to be DF/DHF. The conventional serological procedure, the Haemagglutination Inhibition (HI) test, for the diagnosis of DF/DHF is cumbersome and causes delay in diagnosis. Another problem associated with the HI test has been that it has often been difficult to obtain a second convalescent serum sample for an accurate diagnosis. This has raised an urgent need to establish a "rapid" test for diagnosis of DF/DHF. As such the authors recently carried out an evaluation of a newly available commercial rapid test, namely, the Dengue Blot Assay (Diagnostic Biotechnology Singapore Pte Ltd). The test is intended for use in laboratory confirmation of dengue virus infection. The evaluation was to determine if the test could be utilised as a routine laboratory test and to establish its sensitivity and specificity. Over 400 samples were tested against the Dengue Blot Assay. Results were checked against an in-house Dengue IgM ELISA and HI assay. Preliminary results indicate that the sensitivity and specificity of the Dengue Blot is satisfactory. Our results also indicate that the Dengue Blot has a useful role to play in a routine laboratory especially since it provides rapid results on single serum samples thereby reducing the workload in a busy diagnostic laboratory.

[Effect of d-catechin on carbon tetrachloride- and d-galactosamine-induced cytotoxicity in primary cultured rat hepatocytes]

The effects of d-catechin (d-CTC) on carbon tetrachloride- and d-galactosamine (d-Ga1N)-induced cytotoxicity in primary cultured rat hepatocytes were examined. After 1.5 h preincubation, d-CTC was added at doses of 0.1-5.0 mg/ml to culture medium together with 10 mmol/L CCl4 or 5 mmol/L d-GalN, respectively. GOT, GPT and LDH levels were measured 1.5 h after treatment. The results showed that d-CTC at doses of 0.6 to 5.0 mg/ml could protect the hepatocytes against the toxic effects of CCl4 and d-GalN. At the higher doses (2.5-5.0 mg/ml), d-CTC showed weak inhibition of LDH and GPT activities, but these did not influence its anti-hepatotoxic activity.

Markers of hepatitis B virus infection in asymptomatic drug abusers in Malaysia

Sera from 200 Malaysian male drug abusers were tested for markers of Hepatitis B virus (HBV) infection, viz. HBsAg, HBeAg, anti-HBs and anti-HBc using commercially available enzyme immunoassay (EIA) kits supplied by Abbot Laboratories, Chicago. Of these, 103 (51.5%) were positive for at least one HBV marker, 11 (5.5%) were positive for HBsAg; 4 (2%) for HBeAg, 74 (37%) for anti-HBs and 85 (42.5%) for anti-HBc. The HBsAg carrier rate was roughly the same as the carrier rate in the general population of Malaysia. The majority of drug abusers (95%) have had subclinical, asymptomatic HBV infection. Racially the Malay drug abusers had the highest exposure rate (54.2%). The HBsAg carrier rate was highest in the Chinese drug abusers (15.3%) and lowest in the Indians (0%). The mean age for the HBsAg carriers was found to be 26 years with a mean duration of drug abuse of 72 months. The Malaysian Anti-Narcotics Task Force of the National Security Council reported in the Malay Mail (July 13, 1985) that there were about 106,000 identified drug abusers in Malaysia and that 63% of these were in the 20-29 age groups. It appears from our study that this age group also coincides with the period of high HBsAg carrier rate. Age wise, those less than 21 years old had the highest HBsAg (11%) and HBeAg (5.6%) prevalence rates indicating high infectivity. After the age of 30 years, nearly 50% of the drug abusers appear to be immune with the HBe prevalence of 0%.(ABSTRACT TRUNCATED AT 250 WORDS)

Hepatitis B markers in non-icteric medical patients in Malaysia

Sera were obtained from 494 non-icteric patients admitted with illnesses other than overt hepatitis into the medical wards of the rural and urban hospitals in Malaysia. They were tested for HBsAg, HBeAg, and anti-HBs by enzyme immunoassay. The overall HBsAg carrier rate was 18.0% ranging from 9.6% in children, (10 years and under), to a maximum of 23.5% in the adolescents (11 to 20 years), the rates decreasing subsequently to 16.5% and 20.8% in the adult and middle-age groups, respectively. The Chinese (18.6%) and Malays (19.9%) had similar HBsAg carrier rates but the rate in the Indians (9.0%) was distinctly lower. Similar rates were observed in the males (16.5%) and the females (19.8%). The carrier rate was 17.1% in rural patients compared with 21.4% in the urban ones. The 'e' antigen was found in 14 of the 89 HBsAg carriers (15.7%). The overall prevalence was 14/494 (2.8%) rising sharply from childhood (2.9%) to adolescence (5.3%), subsequently declining with advancing age. The Chinese had the highest rate (6.2%) followed by the Indians (1.5%) and the Malays (1.1%). Males had a rate of 3.3% compared to the females with 2.3%. Anti-HBs was found in 33.8% of the patients, increasing steadily from childhood (18.3%) to middle-age (46.4%). The Chinese had a higher prevalence rate (41.6%) than the Indians (32.8%) and the Malays (29.3%). The rates were similar for the males (35.6%) and the females (31.5%). Rural patients (46.1%) had a higher rate than urban patients (35.7%). Both areas showed rising prevalence with increasing age.(ABSTRACT TRUNCATED AT 250 WORDS)

Aetiology of acute hepatitis in Malaysia

Icteric patients with clinical and biochemical evidence of liver disease, admitted into various hospitals in Malaysia, were investigated to determine the cause of their infection. Of these patients, 11.0% (16/145) were found positive for IgM anti-HAV (EIA), 4.1% (6/145) for IgM anti-HBc (EIA), 1.0% (1/102) for IgM anti-CMV (ELISA), 17.2% (16/64) for rising titres of leptospiral agglutinin, and none for heterophile antibody of EBV. Hepatitis NANB accounted for 67.9% of cases. The mean serum transaminases (ALT and AST) values in patients with hepatitis A and B were higher (more than 500IU) than in patients with leptospirosis or non-A, non-B hepatitis, whereas serum bilirubin levels were higher in patients with hepatitis A and leptospirosis than in patients with hepatitis B.

A seroepidemiologic study of hepatitis A in Malaysia

Sera from 494 non-icteric patients admitted with illnesses other than overt hepatitis into the various hospitals in rural and urban Malaysia were tested for IgG antibody to hepatitis A virus. The overall antibody prevalence rate was 67.0% with rates increasing steadily from childhood 10 years old and under (39.4%) to middle-age and above (96.0%). No significant differences were noted between males (68.4%) and females (65.3%). The highest rate was in the Indians (80.6%), the lowest in the Chinese (55.9%) with Malays occupying intermediate position (70.3%). The rate in the rural patients (74.7%) was higher than that in the urban patients (65.5%) especially in the 21 to 40 year age-group where the rural patients had a rate of 96.7% compared with that in urban patients (61.1%). A comparison of antibody prevalence rates in different countries was made.

Rainfall, abundance of Aedes aegypti and dengue infection in Selangor, Malaysia

An epidemio-meteorotropic analytical study of Selangor, in the Southwest coast of Peninsular Malaysia, examines the monthly incidence of dengue for the period 1973-1982 to assess possible quantitative association with the monthly rainfall. The relationships between rainfall, abundance of A. aegypti and dengue infection during 1982 in Jinjang, a dengue-prone area in Selangor, were also examined. A quantitative association between rainfall and the number of dengue cases was found during the first wet period. The lag time between the onset of heavy rain and dengue outbreak was about two to three months. A 120% increase in the number of dengue cases was observed when the monthly rainfall was 300 mm or more. Positive associations were seen between the incidence of dengue and the Aedes house index and the Breteau index in Jinjang. The relationships between these three variables and rainfall suggest that the latter might have exerted its effect on dengue infection partly through the creation of more breeding sites for A. aegypti. Assessment of the importance of A. aegypti in the transmission of dengue in this locality was not possible because of the lack of adjustment for A. albopictus, the other known vector of dengue in the state, and for social and other environmental factors influencing infection rates. In spite of this and the interpretational problems common in aggregate studies, the present analyses have provided relatively strong statistical evidence of an association between rainfall and dengue outbreaks in Selangor, thereby indicating that it is a factor worthy of careful surveillance and monitoring.

The 1982 dengue epidemic in Malaysia: epidemiological, serological and virological aspects

In 1982, Malaysia experienced the worst dengue/dengue haemorrhagic fever outbreak in its history. All states in Peninsular and East Malaysia were similarly affected. There was a total of 3,005 cases with 35 deaths, with the majority of cases occurring between the months of July to October. There was a total of 1,001 laboratory confirmed cases. Most of the cases were in patients over the age of 15 years. The Chinese population was mainly affected, although a much higher proportion of Malays was noted in comparison to previous years. The main serotypes involved were dengue-1 and dengue-3. No dengue-4 serotype were isolated.

Antigenic drift between the haemagglutinin of the Hong Kong influenza strains A/Aichi/2/68 and A/Victoria/3/75

A DNA copy of the gene coding for the influenza A/Aichi/2/68 haemagglutinin protein was cloned in the plasmid pBR322 and the complete nucleotide sequence determined. Comparison of this primary structure and the deduced amino acid sequence with the haemagglutinin gene and protein of strains belonging to the same (H3) subtype and to different subtypes, of both human (H2) and avian (Hav1) origin, documents further at the molecular level the two independent modes of antigenic variation of the virus--drift and shift.

Complete structure of the hemagglutinin gene from the human influenza A/Victoria/3/75 (H3N2) strain as determined from cloned DNA

The complete sequence of a hemagglutinin (HA) gene of a recent human influenza A strain, A/Victoria/3/75, is 1768 nucleotides long and contains the information for 567 amino acids. It codes for a signal peptide of 16 amino acids, the HA1 chain of the mature hemagglutinin of 329 amino acids, a connecting region between HA1 and HA2 consisting of a single arginine residue and the HA2 portion of 221 amiino acids. The sequence is compared with the hemagglutinin of two members of other subtypes, the human H2 strain A/Jap/305/57 and the avian Hav1 strain A/FPV/Rostock/34, and with one of the same H3 subtype, A/Memphis/3/72. To align the HA1 chain of different major subtypes several deletions/insertions of single amino acids must be invoked, but two more extensive differences are found at both ends, one leading to an extension of the amino terminal sequence of HA1 and the other (four residues) occurring in the region processed away between HA1 and HA2. Comparison of the HA1 of two H3 strains suggests that drift probably depends on single base mutations, some of which change antigenic determinants. The HA2 region, which apparently is not involved in the immune response, is highly conserved even between different subtypes, and single base substitutions account for all the observed diversity. A hydrophobic segment of 24 residues is present in the same position close to the carboxyl terminus of HA2 in both Victoria and FPV, and presumably functions in implantation into the lipid bilayer. The many conserved features not only in HA2 but also in HA1 suggest a rather rigid architecture for the whole hemagglutinin molecule.