Prognostic value of circulating plasma cells detected by flow cytometry in newly diagnosed multiple myeloma patients: a systematic review and meta-analysis

OBJECTIVES

Multiple myeloma (MM) is a malignant plasma cell disorder. The most widely accepted staging system for MM is the revised International Staging System based on cytogenetic and clinical biomarkers. The circulating clonal plasma cells (CPCs) were reported to have potential prognostic impact on MM. Among various diagnostic approaches, multiparametric flow cytometry (FCM) offers heightened sensitivity, minimal invasiveness and reproducibility. We conducted a meta-analysis to evaluate the prognostic value of quantifying CPCs via FCM in newly diagnosed symptomatic MM (NDMM) patients.

DESIGN

Systematic review and meta-analysis.

DATA SOURCE

PubMed, Web of Science, Embase and references of included studies.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

We included observational studies that evaluated the prognostic value of CPCs detected by FCM in NDMM.

DATA EXTRACTION AND SYNTHESIS

Data were screened and extracted independently by two investigators. The pooled results originated from random effects models. The primary endpoint was overall survival (OS). The secondary endpoint was progression-free survival (PFS). To evaluate the prognostic value of CPCs in NDMM, HRs and their 95% CI for both OS and PFS were derived using COX multivariable models. These values were then used to compute the pooled estimated effect.

RESULTS

Our meta-analysis encompassed a total of 2704 NDMM patients from 11 studies up to 27 August 2022. The pooled HR for OS and PFS in CPC-positive (CPCs+) group and CPC-negative group were 1.95 (95% CI 1.24 to 3.07) and 2.07 (95% CI 1.79 to 2.39), respectively. The autologous stem cell transplantation (ASCT) failed to eliminate the adverse impact on OS and PFS. The heterogeneity may stem from the use of novel agents or traditional chemotherapy as initial treatment.

CONCLUSION

This meta-analysis indicates CPCs+ had an adverse impact on the prognosis of NDMM patients in the total population, and the adverse impact could not be eliminated by ASCT.

PROSPERO REGISTRATION NUMBER

CRD42021272381.

Identification of Potential Signatures and Their Functions for Acute Lymphoblastic Leukemia: A Study Based on the Cancer Genome Atlas

Objective

Acute lymphoblastic leukemia (ALL) is a malignant disease most commonly diagnosed in adolescents and young adults. This study aimed to explore potential signatures and their functions for ALL.

Methods

Differentially expressed mRNAs (DEmRNAs) and differentially expressed long non-coding RNAs (DElncRNAs) were identified for ALL from The Cancer Genome Atlas (TCGA) and normal control from Genotype-Tissue Expression (GTEx). DElncRNA-microRNA (miRNA) and miRNA-DEmRNA pairs were predicted using online databases. Then, a competing endogenous RNA (ceRNA) network was constructed. Functional enrichment analysis of DEmRNAs in the ceRNA network was performed. Protein-protein interaction (PPI) network was then constructed. Hub genes were identified. DElncRNAs in the ceRNA network were validated using Real-time qPCR.

Results

A total of 2,903 up- and 3,228 downregulated mRNAs and 469 up- and 286 downregulated lncRNAs were identified for ALL. A ceRNA network was constructed for ALL, consisting of 845 lncRNA-miRNA and 395 miRNA-mRNA pairs. These DEmRNAs in the ceRNA network were mainly enriched in ALL-related biological processes and pathways. Ten hub genes were identified, including SMAD3, SMAD7, SMAD5, ZFYVE9, FKBP1A, FZD6, FZD7, LRP6, WNT1, and SFRP1. According to Real-time qPCR, eight lncRNAs including ATP11A-AS1, ITPK1-AS1, ANO1-AS2, CRNDE, MALAT1, CACNA1C-IT3, PWRN1, and WT1-AS were significantly upregulated in ALL bone marrow samples compared to normal samples.

Conclusion

Our results showed the lncRNA expression profiles and constructed ceRNA network in ALL. Furthermore, eight lncRNAs including ATP11A-AS1, ITPK1-AS1, ANO1-AS2, CRNDE, MALAT1, CACNA1C-IT3, PWRN1, and WT1-AS were identified. These results could provide a novel insight into the study of ALL.

LncRNA CRNDE Promotes the Progression of B-cell Precursor Acute Lymphoblastic Leukemia by Targeting the miR-345-5p/CREB Axis

The imbalance between the proliferation and apoptosis of B-cell precursors is an important contributor to the pathogenesis of B-cell precursor acute lymphoblastic leukemia (BCP-ALL), while its specific regulatory mechanism remains perplexing. This study aimed to expound the underlying mechanism of the proliferation and apoptosis of BCP-ALL cells from the perspective of non-coding RNA. In this study, long non-coding RNA colorectal neoplasia differentially expressed (LncRNA CRNDE) was upregulated in the bone marrow of BCP-ALL patients and BCP-ALL cell lines (NALM-6 and RS4;11). Functionally, LncRNA CRNDE knockdown restrained cell proliferation and boosted cell apoptosis in NALM-6 and RS4;11 cells. The subsequent investigation confirmed that LncRNA CRNDE bound to miR-345-5p and negatively regulated miR-345-5p expression. The overexpression of miR-345-5p suppressed cell proliferation and boosted cell apoptosis in NALM-6 and RS4;11 cells. Further experiments revealed that miR-345-5p downregulated cyclic AMP response element-binding protein (CREB) expression by targeting its mRNA directly. CREB overexpression reversed the effect of miR-345-5p mimic on cell proliferation and apoptosis in NALM-6 and RS4;11 cells. Finally, in vivo experiments showed that LncRNA CRNDE knockdown prolonged the survival of mice xenotransplanted with NALM-6 cells. In conclusion, LncRNA CRNDE upregulated CREB expression by suppressing miR-345-5p, thus promoting cell proliferation and reducing cell apoptosis in BCP-ALL.

Artesunate induces apoptosis and inhibits the proliferation, stemness, and tumorigenesis of leukemia

Background

Leukemia is characterized by the presence of highly malignant tumors formed in the hematopoietic system. Artesunate (Art), a semi-synthetic derivative of artemisinin, is commonly used as an antimalarial drug and has been proven to possess anticancer potential.

Methods

In this study, the effect of Art on the proliferation and stemness of human acute promyelocyte leukemia HL-60 cells and acute myeloid leukemia KG1a cells was investigated. Flow cytometry, colony formation assay, the protein expressive levels of survivin, P21, cleaved caspase 3, Bax, Bcl-2, Ki67 were detected the effect of Art on HL-60 and KG1a cells proliferation and apoptosis. At the same time, cell sphere formation assay and the protein expressive levels of CD44, SOX2, ALDH1 and OCT4 were used to analyze the effects of Art on cancer stem cell-like property in vitro. The orthotopic xenograft mouse models were established by using KG1a cells in BALB/c athymic nude mice. Tumor weigh was detected. The protein levels of survivin and Ki67 were detected by immunohistochemistry assays.

Results

Art induced cell apoptosis and inhibited cell proliferation and stemness in a dose-dependent manner. In the meantime, the results exhibited that Art inhibited the growth and stemness of transplanted tumors via the suppression of the MEK/ERK and PI3K/Akt pathway.

Conclusions

Our present study provides new insights into the mechanisms of Art’s anticancer potential in leukemia.

Knockdown of ZFAS1 suppresses the progression of acute myeloid leukemia by regulating microRNA-150/Sp1 and microRNA-150/Myb pathways

Leukemia is the most frequent malignancy in children with acute myeloid leukemia (AML) as the second commonest type. Long non-coding RNA zinc finger antisense 1 (ZFAS1) has been widely reported as an oncogenic factor in multiple malignancies including AML. However, the roles and molecular mechanisms of ZFAS1 in the tumorigenesis of AML are poor defined till now. In the present study, RT-qPCR assay showed that ZFAS1 was highly expressed in bone marrow of acute leukemia patients and AML cell lines. Loss-of-function analyses revealed that ZFAS1 knockdown inhibited proliferation and promoted apoptosis in AML cells and curbed AML xenograft growth in vivo. Bioinformatics analysis and luciferase reporter assay unveiled that microRNA-150 (miR-150) could interact with ZFAS1, Myb 3' UTR and Sp1 3' UTR. Moreover, ZFAS1 acted as a molecular sponge of miR-150, giving rise to the downregulation of miR-150 level and upregulation of Myb and Sp1 levels. Moreover, miR-150 overexpression resulted in the reduction of AML cell proliferative ability and the increase of cell apoptotic rate. Additionally, the inhibition of miR-150 abrogated ZFAS1 loss-mediated anti-leukemia effects. In summary, our data demonstrated that ZFAS1 knockdown hampered AML progression by regulating miR-150/Myb and miR-150/Sp1 pathways, providing some potential biomarkers or targets for the diagnosis and treatment of leukemia.

Ablation of MCM10 using CRISPR/Cas9 restrains the growth and migration of esophageal squamous cell carcinoma cells through inhibition of Akt signaling

Introduction

Minichromosome maintenance 10 (MCM10) is deregulated in several malignancies including cervical cancer and urothelial carcinoma. However, the expression and biologic role of MCM10 in esophageal squamous cell carcinoma (ESCC) is still unknown.

Methods

In this study, we performed immunohistochemistry and real-time polymerase chain reaction (PCR) analysis to examine the expression of MCM10 in ESCC and adjacent normal esophageal tissues. The associations of MCM10 expression with clinicopathologic parameters of ESCC were analyzed. Ablation of MCM10 through the CRISPR/Cas9 technology was conducted and its impact on ESCC cell growth and migration was investigated.

Results

The mRNA and protein expression levels of MCM10 were significantly greater in ESCC than in normal tissues (P<0.001). The expression of MCM10 was significantly associated with age at diagnosis (P=0.033), but not with gender, differentiation grade, invasion status, or tumor–node–metastasis (TNM) stage. Knockout of MCM10 significantly suppressed the proliferation, colony formation, and migration capacity of EC109 ESCC cells, compared to control cells harboring wild-type MCM10. Mechanistically, MCM10 depletion markedly reduced the phosphorylation of Akt. Overexpression of constitutively active Akt significantly restored the aggressive phenotype of MCM10-null EC109 cells.

Conclusion

In conclusion, these results suggest that MCM10 acts as an oncogene in ESCC through activation of Akt signaling and represents a promising therapeutic target for this malignancy.

Antimicrobial resistance patterns, clinical features, and risk factors for septic shock and death of nosocomial E coli bacteremia in adult patients with hematological disease: A monocenter retrospective study in China

The aim of this retrospective analysis was to evaluate the antimicrobial resistance, clinical features, and risk factors for septic shock and death of nosocomial E coli bacteremia in adult patients in a single hematological center in China. A retrospective case-control study of 157 adult hematological patients with 168 episodes of E coli bacteremia was initiated from April 2012 to July 2015. Antimicrobial susceptibility as well as antimicrobial co-resistance rates were analyzed. Clinical features and outcomes were also studied. In addition, risk factors for septic shock and death were investigated. Among the 553 positive blood isolates during the study period, the prevalence of E coli was 33.3% and ESBL production strains represented 61.9% of those examined. In all the E coli strains isolated, 85.6% were multidrug-resistance (MDR), 2.4% were extensive drug resistance (XDR), and 6.0% were resistant to carbapenems. More MDR phenotype was noted in ESBL-EC strains (98.6% vs 62.8%, P<.001) and isolates from neutropenic patients (98.6% vs 62.8%, P < .001). In the antimicrobial susceptibility test, carbapenems and amikacin exhibited not only higher in vitro activity against E coli (94.0% and 92.0%, respectively), but lower co-resistance rates to other antibiotics. Carbapenem resistant strains retained full sensitivity to tigecycline and 60% to amikacin. Piperacillin/tazobatam was the third sensitive drug to both ESBL-EC (77.1%) and non-ESBL-EC (86.0%). In our series, 81.6% episodes received appropriate initial antibiotic treatment and no significant decrease in it was found in bacteremia due to ESBL E coli and patients with neutropenia, septic shock. Septic shock was noted in 15.5% patients and the overall 30-day mortality rate was 21.7%. Multivariate analysis revealed that induction chemotherapy (OR 2.126; 95% CI 1.624-11.332; P = .003) and polymicrobial infection (OR 3.628; 95% CI 1.065-21.219; P = .041) were risk factors for septic shock, whereas male (OR 2.223; 95% CI 1.132-12.022; P < .01) and septic shock (OR 52.359; 95% CI 19.951-292.690; P = .030) were risk factors for death.In the hematology department, ESBL-producing and MDR are widely prevalent in E coli bacteremia which is still a major life-threatening problem, especially for patients with septic shock. For empirical antimicrobial therapy, combination based on aminoglycoside, especially amikacin, will be helpful to increase the antimicrobial coverage against ESBL-EC while combining tigecycline with aminoglycoside should be considered for seriously carbapenem-resistant infectious patients.

[The clinical study of invasive fungal infection in 76 cases of hematologic diseases]

OBJECTIVE

To investigate the risk factors, clinical features, efficacy and adverse reactions in patients of hematologic diseases with invasive fungal infections (IFI).

METHODS

The risk factors and clinical features were retrospectively analyzed to compare the efficacy and safety of itraconazole with amphotericin B in treatment of IFI in 76 patients with hematologic diseases.

RESULTS

Of the 76 patients, 68 (89.5%) used broad-spectrum antibiotics, 64 (84.2%) were treated with more than 2 courses chemotherapy, 43 (56.6%) were under agranulocytosis, 34 (44.7%) were using glucocorticoid for long terms, 27 (35.5%) were with peripheral or central venous catheter. The overall effective rates of itraconazole and amphotericin B were 60.5% and 61.5% respectively (P = 0.929). There was a significant difference between itraconazole and amphotericin B in hypokalemia (14.0% vs 42.4%, P = 0.005) while no other differences in adverse reactions were found.

CONCLUSIONS

The risk factors of patients in hematologic diseases with IFI include chemotherapy, using broad septum antibiotics and agranulocysis. The therapeutic effect of itraconazole and amphotericin B in treatment of IFI is similar. The adverse reactions of itraconazole is less and slighter than amphotericin B.

Occupational chromate allergy in Singapore: a study of 87 patients and a review from 1983 to 1995

BACKGROUND

The prevalence of chromate allergy among all patients tested at the Contact and Occupational Dermatoses Clinic at the National Skin Centre in Singapore had fallen progressively from 1983 to 1989. Chromate has also become a less common occupational allergen because of the decline in the number of cases of allergic contact dermatitis from cement.

OBJECTIVE

The aim of this report was to study and update the epidemiology of occupational chromate allergy among workers seen in a tertiary dermatology referral centre in Singapore from 1990 to 1995 and to review the changing trends of occupational chromate allergy in our local setting since 1983. The occurrence of concomitant contact allergens among was also studied.

METHODS

All patients diagnosed to have occupational allergic contact dermatitis together with positive reactions to chromate, at the Joint Occupational Dermatosis Clinic at the National Skin Centre in Singapore, between January 1990 to December 1995, were included. Causes of chromate allergy and frequency of occurrence of concomitant contact allergens among construction and nonconstruction workers were compared.

RESULTS

Eight hundred and fifty workers were seen during the 6-year-study period. Six hundred and thirty three (74.5%) were diagnosed to have occupational contact dermatitis, of which 257 (40.6%) had allergic contact dermatitis. Eighty-seven (33.8%) of these workers had positive reaction to chromate on patch testing. Ninety-five percent of these workers were men with a mean age of 33.4 years. The construction industry contributed 59% of the workers with chromate allergy. Cement (61%) remained the most common source of chromate allergy in our workers, and chromate from sources other than cement (39%) accounted for the rest. Of workers allergic to chromate from cement, 96% (51 of 53) came from the construction industry. Sixty percent of the workers with chromate allergy had concomitant contact allergens and the coexistence of two or more allergens was significantly more common among nonconstruction workers (53%) than construction workers (22%). The three most common concomitant contact allergens were cobalt (28%), rubber chemicals (21%) and nickel (18%). Nonconstruction workers had significantly higher rates of nickel allergy (36% v 6%) than construction workers (P < .03). Simultaneous reactivity to cobalt and nickel was also significantly more common among nonconstruction workers (22%) than construction workers (6%) (P < .03).

CONCLUSION

Chromate has progressively become a less common occupational allergen at the National Skin Centre in Singapore from 1983 to 1989, because of a progressive fall in the number of cases of allergic contact dermatitis from cement. However, our study showed that occupational chromate allergy had now increased from 1990 to 1995, because of an increase in chromate allergy from sources other than cement. Chromate allergy from cement is declining, although still frequent, and sources other than cement are increasing in recent years. Concomitant nickel allergy, as well as simultaneous nickel and cobalt allergies, were more common among nonconstruction workers than construction workers.

Sickness absence in private sector establishments in Singapore

AIM

A study was conducted in June 1995 to determine the current level of sickness absence in Singapore.

METHOD

The questionnaire survey was part of a larger labour market survey conducted quarterly by the Ministry of Labour, and covered 3,553 private sector establishments employing 25 or more employees.

RESULTS

Overall, 14.4% of the 628,477 employees took sick leave, while the percentage of working days lost due to sick leave, excluding maternity leave, was 1.1%. An average of 3.2 days of medical leave were taken per person per year. Industry specific characteristics seemed to have more influence on sickness absence than establishment size, employee's sex and occupation (viz, professional versus clerical versus production staff), number of hours worked and overtime work. Over 60% of the establishments, particularly larger companies and those in manufacturing, implemented measures to control sickness absence, most commonly counselling, disciplinary procedures and attendance allowance or bonus. Over 13% monitored sickness absence using computerised records.

CONCLUSION

Comparing with overseas sickness absence (lost time) rates, the rates observed in this study do not appear high.

Change in cement manufacturing process, a cause for decline in chromate allergy?

Hexavalent chromate in cement is the commonest cause of allergic contact dermatitis, especially among construction workers. Over the past decades, there has been a general decline in the prevalence of chromate allergy among construction workers. We suspect that a change in the constituents of cement, resulting in the lowering of hexavalent chromate, contributed to the decline. Slag (free from hexavalent chromate) from the iron-quenched, blast furnace process has been used as a substitute for clinker (which contains high hexavalent chromate) in manufacturing cement. As a result, the slag has diluted the hexavalent chromate content of cement. Our analytical study showed that slag is free from hexavalent chromate and that the hexavalent chromate of clinker ranged from 6-17 micrograms/g. Substituting slag for clinker resulted in dilution of hexavalent chromate in the cement. The hexavalent chromate content of cement declines proportionately with increasing proportion of slag, e.g., a cement containing 5% slag has a total hexavalent chromate concentration of 17.5 micrograms/g, whereas increasing the proportion of slag to 60% reduced the hexavalent chromate content to 7.1 micrograms/gm in the same cement.

Cadmium hazard in silver brazing

This study evaluates the usage of cadmium-containing silver brazing alloys in Singapore and the potential cadmium hazard from its use. Of the 137 factories which responded to the survey questionnaire, only 28 (20.4%) carried out brazing. Of these, only 7 factories used cadmium-containing filler alloys. One hundred and six out of 123 workers from one of these factories had cadmium-in-blood concentrations exceeding 10 mcg/l. Thirty-one (29.2%) of the workers with excessive cadmium absorption had urinary beta-2 microglobulin levels exceeding 28 mcg/g creat. Workers in the other factories who were intermittently exposed had cadmium-in-blood concentrations of 10 mcg/l and below.

Urinary beta 2- and alpha 1-microglobulin levels in normal subjects in Singapore

Differing normal values for urinary beta 2-microglobulin have been reported for different countries. In this study, we have attempted to establish the urinary beta 2- and alpha 1-microglobulin levels of apparently healthy subjects in Singapore. Urine samples collected from 271 subjects were analysed. The subjects ranged from 19 to 62 years old, with a mean age of 36.8 years. The majority (84.5%) were non-smokers. Urine samples with a pH level < 5.5 were excluded from the analysis. The urinary beta 2- and alpha 1-microglobulin values followed log normal distributions. Their 95th percentiles were 288 micrograms/g creatinine and 7.35 mg/g creatinine, respectively. Statistically significant differences were found between sexes and ethnic groups for urinary beta 2-microglobulin values. Both alpha 1- and beta 2-microglobulin values increased significantly with age. Smokers had significantly higher urinary alpha 1-microglobulin values.

Efficacies of a barrier cream and an afterwork emollient cream against cutting fluid dermatitis in metalworkers: a prospective study

We compared the point prevalence of cutting fluid dermatitis and transepidermal water vapour loss (TEWL) changes in groups of new machinists who (a) used a barrier cream; (b) used an afterwork emollient cream; and (c) did not use any cream (controls) over a 6-month period. All machinists handled cutting fluid (neat mineral oil) during their work. There was no significant difference in the prevalence of cutting fluid dermatitis in the 3 groups throughout the study period. The prevalence of cutting fluid dermatitis in all groups increased rapidly during the first 6 weeks and thereafter remained steady throughout the remainder of the study period. The prevalence of cutting fluid dermatitis was slightly lower in machinists using afterwork emollient cream compared to those using barrier cream and controls (not significant). The differences in the mean TEWL changes during the study period among the 3 groups were also not statistically significant. The mean TEWL values in the 3 groups increased rapidly during the first 6 weeks of exposure to cutting fluids and thereafter remained fairly constant throughout the remainder of the study period. Barrier cream and afterwork emollient cream did not appear to have any significant effect against either cutting fluid dermatitis or TEWL changes in machinists exposed to cutting fluid. However, afterwork emollient cream appeared clinically to help reduce the prevalence of cutting fluid irritation.

The incidence of cutting fluid dermatitis among metalworkers in a metal fabrication factory: a prospective study

We compared the incidence of occupational dermatitis and transepidermal water vapour loss (TEWL) changes from cutting fluids (neat mineral oils) in 24 new machinists with 27 armed forces paramedics (controls) over a 6-month period. The cumulative incidence of occupational dermatitis in positive controls increased from 38% at week 3 to 77% at week 6. It then decreased to 50% at week 9 and thereafter remained constant at about 50% throughout the remaining study period. 2 workers sought medical treatment for their dermatitis. Only 1 worker had a job transfer because of his dermatitis. None of the paramedics developed dermatitis during the study period. The mean basal TEWL values on the hands of machinists and controls were 17.6 and 14.5 g/m2/h (n.s.) respectively. The mean TEWL values of machinists increased to 22 g/m2/h by week 3 and then remained fairly constant throughout the remaining study period. The mean TEWL of negative controls remained fairly constant (at about 14 g/m2/h) from the beginning to the end of the study period. The mean TEWL value of machinists was significantly higher than that of negative controls throughout the study period. There was no significant difference in the prevalence of cutting fluid dermatitis between machinists with high basal TEWL values (> or = 17 g/m2/h) and those with low basal TEWL values (< 17 g/m2/h).

Use of a computerized postural sway measurement system for assessing workers exposed to manganese

1. Computerized postural sway measurement systems have been used recently in human physiology and pharmacology for determining postural stability, but their applicability for the assessment of the effects of exposure to neurotoxic agents is lacking. 2. We have examined the feasibility of using a computerized postural sway measurement system to assess the postural sway parameters of manganese exposed workers compared with a control group. 3. Sway parameter data were collected using a KISLTER multicomponent measuring platform (Type 9281B) connected to VICON motion analysis system for 13 exposed and 16 control subjects. 4. Significant differences in several of the sway parameters (Px, Py--mean distance (mm), from the centre of the platform along the X-axis [anterior-posterior movement] and Y-axis [lateral movement], respectively) between the exposed and control groups were observed even after adjustment for possible confounders. Computerized postural sway measurement system may be a useful method of assessing workers exposed to neurotoxic agents affecting posture.

Neurobehavioral functions among workers exposed to manganese ore

The Neurobehavioral Core Test Battery of the World Health Organization was performed on 17 baggers (mean age 36.6 years) in a manganese ore milling plant and 17 referents (mean age 35.7 years). The baggers had a mean exposure period of 7.4 (range 1-14) years with a mean blood manganese concentration of 25.3 (range 15-92.5) micrograms.l-1 [0.46 (0.27-1.68) mumol.l-1]. Of the 37 symptoms related to the nervous system, 20 were more frequently reported by the exposed workers. No significant differences were noted between the nerve conduction of the median and ulnar nerves of the dominant forearm of the two groups. The exposed workers had significantly poorer motor speed, visual scanning, visuomotor coordination, visuomotor and response speed, and visuomotor coordination and steadiness. A clinical examination did not reveal any abnormality among the two groups. Hence a neurobehavioral test battery may be a more sensitive method than a clinical examination in detecting early changes in motor function among manganese-exposed workers.

Study on the health of female electronics workers on 12 hour shifts

Health complaints, blood pressure, sleep and sickness absence experience were studied in 308 female electronics workers employed for at least one year on 12 h shifts--253 on permanent and 55 on rotating schedules. Seventy-five 8 h day workers acted as controls. There were no significant differences in symptom prevalence between the controls and 12 h shift workers, except for complaints of tiredness, with a higher proportion of the rotating shift group also having headaches. No significant differences in prevalence of hypertension were noted. Although subjects on the night shift had shorter sleep than controls and 12h day workers, only the group on rotating schedule had a higher proportion of workers who did not sleep well compared to the controls. Sickness absence was not increased in the 12 h shift groups when compared to the controls. The results indicate no serious health problems among workers on 12 h shift for over a year.

Shiftwork in Singapore

In 1985, over 94,000 persons were engaged in shiftwork. With the continued emphasis on capital-intensive industries and growing demand for "round-the-clock" services, shiftwork is increasingly becoming an economic necessity in many industries in Singapore. A survey in 1991 confirmed this trend. The study covered 4,996 private sector establishments employing 25 or more paid employees. 34.4% of the establishments had shiftworkers. In terms of employees, 32% or 206,965 employees were working shifts. While the 8-hour shift schedule was still the predominant pattern, there was a ten-fold increase in the number of 12-hour shiftworkers. A trend towards permanent shift schedules was also noted. It was interesting that the proportion of shiftworkers doing nightwork decreased to 36.9% from 45.1% in 1985. The health implications of shiftwork have been widely reported. So far, our own studies indicate no serious long-term health effects among shiftworkers. However, further studies are needed to determine if preventive measures can be taken to minimise the common complaints of sleep problems and tiredness, particularly among rotating shiftworkers.

Persistent liver dysfunction among workers at a vinyl chloride monomer polymerization plant

Thirteen workers with persistent abnormalities in one or more liver function tests (LFT) at a vinyl chloride monomer (VCM) polymerization plant were investigated. Twelve workers were found to have VCM-induced liver dysfunction based on circumstantial evidence. They were employed between 1971 and 1982 when the VCM levels ranged from 1 to 21 p.p.m. After 1982 when the environmental VCM levels were controlled to below 1 p.p.m., no cases of VCM-induced liver dysfunction were detected. In most cases, glutamic pyruvic transaminase was the earliest parameter to be raised. The second most common parameter is serum gamma glutamyl transpeptidase. The latent period ranged from 1 to 13 years. An improvement in their LFT results was shown by 83.3 per cent of workers within 6 months to 2 years after removal from further VCM exposure. For workers who returned to VCM work, their LFT became abnormal again. Liver scans showed hepato and/or splenomegaly in most cases. Liver biopsies on 9 workers were reported as 'non-specific fatty changes' of varying degrees. These observations highlight the need for continual vigilance with environmental monitoring and medical surveillance of VCM-exposed workers.

Sleep-wake patterns and subjective sleep quality of day and night workers: interaction between napping and main sleep episodes

Five hundred and ninety-three women electronics workers were studied to determine if there was any association between their subjective sleep quality and their sleep patterns. They were 108 day workers, 107 permanent night workers, 216 workers on weekly phase-advance (night/afternoon/morning), and 162 workers on two-weekly phase-delay (morning/afternoon/night) rotating shift schedules. The study was part of a larger survey on night workers involving a self-administered questionnaire. The proportion of nappers was higher in night workers than in day, morning, and afternoon shift workers. Nappers had shorter main sleep, but their total sleep duration was generally the same as that of nonnappers. Compared to nonnappers, a higher proportion of day and morning shift workers who napped did not sleep well. Permanent night workers, with the highest proportion of nappers, had more workers sleeping well than rotating night workers. Subjects who slept well were those with longer total and main sleep and generally started the main sleep earlier. The results indicate a relationship between subjective sleep quality, sleep length, main sleep start, and napping behavior. Whether this relationship is causal is difficult to establish as sleep quality may also reflect the general health status, and this may result in differences in sleep behavior.

Chlamydial infection in female prostitutes in Singapore

Three studies conducted in 1982, 1985 and 1988 investigated chlamydial infections in female prostitutes. In 1982, 115 prostitutes with culture-positive gonorrhoea were studied; 8% were coinfected with Chlamydia trachomatis. In 1985, 86 female prostitutes and in 1988, 100 female prostitutes attending for routine tests were examined. Chlamydia trachomatis was isolated in 12% and 9% of the cases, respectively. Gonorrhoea was detected in 10% and 11% of the cases. In the 1988 study, one (9%) of the 11 women with gonorrhoea had concomitant chlamydial infection. Syphilis was diagnosed in 3% of the female prostitutes investigated in 1988. Our findings indicate that concomitant chlamydial infection occurs in about 8-9% of female prostitutes with gonorrhoea and that 9-12% of the female prostitutes screened harboured Chlamydia trachomatis in their endocervices. A chlamydial control programme in prostitutes is desirable.

Occupational dermatosis among sanders in the furniture industry

The prevalence of occupational skin disease was found to be 3.8% in a study of 479 sanders in the furniture-making industry in Singapore. 17 species of wood imported from South East Asia were used. The most common dermatoses from wood dust were pruritus (1.6%), irritant contact dermatitis (1.6%) and xerosis (1.4%). 2 sanders had miliaria. None had allergic contact dermatitis from wood dust. The arms and trunk were the most common site for pruritus and dermatitis from wood dust. It appeared that the woods commonly used in the furniture making industry are weak sensitizers. Appropriate preventive measures against irritant dermatitis such as dust control, protective clothing, and good personal hygiene should be adequate to prevent occupational dermatoses among the sanders.

Occupational dermatitis in a prefabrication construction factory

In a field study of occupational dermatoses in a prefabrication construction factory, 272 workers were interviewed, examined and patch tested to chromate, cobalt, nickel, rubber mixes, epoxy resin, melamine formaldehyde and conplasts. The prevalence of occupational dermatitis was 14% (38/272); 57% (22/38) were irritant dermatitis from cement; 39.5% (15/38) were allergic contact dermatitis from cement (2 with concomitant rubber glove allergy); and 2.5% (1/38) were allergic to rubber chemicals in gloves. The overall prevalence of chromate sensitivity was 8.5% (23/272), with the highest rate from the concreting bays of the factory. The rate was unrelated to the duration of workers' engagement in construction work. 34.8% (8/23) had asymptomatic chromate allergy. The prevalence of cobalt reactions was 17.4% (4/23) and all were associated with chromate allergy.

Cobalt and nickel content of Asian cements

The total cobalt and nickel concentration of 11 brands of Asian cement ranged from 8.1 to 14.2 micrograms/g and 14.9 to 28.5 micrograms/g, respectively. These metals exist mainly as insoluble salts; the water-soluble concentration of cobalt and nickel in the cements ranged from 0.39 to 0.65 micrograms/g and from 0-1.2 micrograms/g, respectively. 1.5% (4/272) of construction workers in a prefabrication construction factory had cobalt sensitivity. All had allergic contact dermatitis from chromate in cement. No worker had isolated cobalt sensitivity and cement dermatitis. It appeared that sensitization to cobalt in cement occurs only secondarily to an existing cement dermatitis. 1.8% (5/272) workers had nickel sensitivity: 2 with allergic contact dermatitis to nickel in their watches, 2 were asymptomatic and 1 had allergic contact dermatitis to chromate and cobalt in cement. The low prevalence of cobalt and nickel sensitivity from cement was probably related to the low concentration of soluble cobalt and nickel salts in the cement. However, these insoluble salts can form soluble complexes with body fluids on eczematous skin and sensitize the skin.

Chromate allergy: total chromium and hexavalent chromate in the air

This is a study on atmospheric concentration of total chromium and hexavalent chromate and its role in chromate sensitivity. Air concentration of total chromium and hexavalent chromate in a construction factory, a busy city area, a suburban area, a residential area, and a heavy industrial area were measured by air sampling pumps. Hexavalent chromate was not detected in any sampled areas. Two (concreting areas) of 8 locations in the construction factory had total chromium of 0.2 and 2.3 micrograms/m3 in the atmosphere. It appeared that the atmospheric concentration of total chromium and hexavalent chromate was negligible. These findings indicate that unexplained chromate sensitivity, as so often seen in patients attending a contact dermatitis clinic, is not attributable to exposure to hexavalent chromate in the air.

Five cases of arsine poisoning

Arsine is one of the most potent haemolytic agents found in industry. Four workers presented with abdominal pain, jaundice and passing tea-coloured urine. A fifth worker also passed dark urine but had no other symptoms. Investigation revealed that all five workers were from a tin smelting plant where they were involved in mixing tin ore with dross. They were exposed to arsine gas after mixing a particularly large quantity of dross with tin ore which was wet because of rain. Three of the cases developed renal impairment and also a mild sensory neuropathy. All survived with proper management in hospital which included exchange blood transfusions, and peritoneal dialysis where indicated. Prevention of such poisoning includes keeping dross away from all moisture, good ventilation in work areas, and adding dross directly to the furnace.