Across-shift lung function variation in cottonseed oil workers

BACKGROUND: The effects of cotton dust on pulmonary function among workers employed in cotton-spinning mills are well known. However, little data exist on the prevalence of this disorder in 'non-textile' cotton industries, including cottonseed oil mills, where high levels of exposure to dust have been demonstrated. AIMS: This study was performed in order to determine the across-shift and across-week decline of FEV(1) and respiratory symptoms among workers in a cottonseed oil mill. METHODS: Sixty-six exposed and 48 unexposed workers of a cottonseed oil mill in Turkey were investigated by questionnaire and lung function test (LFT). LFTs were performed before and after shift on all the working days of the week. Acute airway response was defined as an across-shift decline in FEV(1) of 5% or more on the first working day. RESULTS: Smoking was the only risk factor for having respiratory symptoms. Acute airway response was more frequently observed in the exposed group as compared to the unexposed group (OR = 6.2, 95% CI = 2.3-16.7). The median across-shift decline in FEV(1) on the first day (120 ml) significantly improved on the following days (10, 50, 60 and -30 ml). CONCLUSION: Smoking appears to be the main risk factor for having respiratory symptoms. Cottonseed dust may cause an acute pulmonary function decline on the first working day, but not on the following days of the week. This decline is associated with respiratory symptoms in exposed workers.     

Role of histamine in the aetiology of byssinosis. I Blood histamine concentrations in workers exposed to cotton and flax dusts

The formation or the accumulation, or both, of histamine in the lungs may be potentiated by agent(s) present in cotton dust at higher level(s) than in flax dust and negligible in cottonseed dust. It has been suggested that such potentiation may be due to the activation of the ability of the lung to produce histamine and/or produce or recruit mast cells; this may present an acceptable explanation of the mechanism by which the propagation of the chronic effect of the dust proceeds in cotton and flax workers. Histamine accumulated in the lung over the weekend is released on exposure to dust causing the symptoms of byssinosis. The difference in the rate of histamine metabolism relative to the rate of histamine formation in byssinotic subjects leads to a more prolonged histamine accumulation than in symptom free subjects, with the consequent appearance of the symptoms of byssinosis. Continuous exposure to dust, without weekend interruption, leads to equivalent rates of histamine formation and metabolism with non-considerable histamine accumulation in the lungs and consequent absence of the symptoms of byssinosis.     

Role of histamine in the aetiology of byssinosis. I Blood histamine concentrations in workers exposed to cotton and flax dusts.

The formation or the accumulation, or both, of histamine in the lungs may be potentiated by agent(s) present in cotton dust at higher level(s) than in flax dust and negligible in cottonseed dust. It has been suggested that such potentiation may be due to the activation of the ability of the lung to produce histamine and/or produce or recruit mast cells; this may present an acceptable explanation of the mechanism by which the propagation of the chronic effect of the dust proceeds in cotton and flax workers. Histamine accumulated in the lung over the weekend is released on exposure to dust causing the symptoms of byssinosis. The difference in the rate of histamine metabolism relative to the rate of histamine formation in byssinotic subjects leads to a more prolonged histamine accumulation than in symptom free subjects, with the consequent appearance of the symptoms of byssinosis. Continuous exposure to dust, without weekend interruption, leads to equivalent rates of histamine formation and metabolism with non-considerable histamine accumulation in the lungs and consequent absence of the symptoms of byssinosis.     

Peak Expiratory Flow Rate and Blood Histamine in Textile Mill Workers

Byssinosis is an asthma-like condition in cotton-mill workersand is related to blood histamine and respiratory function.In a preliminary study the peak expiratory flow rate (PERF)values and blood histamine (measured by bioassay method) levelswere compared in workers exposed to cotton dust, i.e. byssinotics(n = 12) and non-byssinotics (n = 12), and unexposed workers(n = 15). The PEFR showed a negative relationship with the histaminelevels of blood in the cotton-dust exposed workers and whencompared to control subjects (P <0.001). The PEFR was maximalwhen blood histamine levels were in a range of 0 to 5 µg/mland dropped down to the lowest level when the blood histaminewas more than 10 µg/ml. This exact relationship was demonstratedby a correlation coefficient and regression equation. This observationis in confirmation with the lung function test of these subjects. Requests for reprints should be addressed to: Dr H. Venkatakrishna-Bhatt, Scientist and Head, Division of Agricultural Health, National Institute of Occupational Health, Meghani Nagar, Ahmedabad 380016 (Gujarat), India.     

Histamine-related reactions in patients with byssinosis

The purpose of the study was to analyze the mechanism of histamine action in histamine-dependent reactions of neutrophils and lymphocytes in patients with byssinosis and chronic asthmatic bronchitis under cotton and flax dust effect. The appraisal of histamine content in blood serum, receptor/histamine distribution of lymphocyte and neutrophil subpopulations (rosette-forming double and triple reactions), determination of histamine modeling effect on lymphocyte-neutrophil cooperation in the inhibition reaction of leukocyte migration revealed that under cotton dust effect neutrophils and the complement system were involved into the histamine liberation process in byssinosis patients, lymphocytes were most likely not involved into the process. Flax dust-affected histamine reactions were not so distinct: lymphocyte and neutrophil reactivity in byssinosis patients did not exceed the standards. Patients with chronic asthmatic bronchitis had high blood concentration of histamine and experienced some changes in cells' migration characteristics. It was assumed that primarily nonimmune mechanisms of histamine liberation and activation of the complement system were involved into byssinosis pathological process in patients exposed to cotton and flax dust effect. In patients with chronic asthmatic bronchitis there occurred all 3 activation mechanisms of biologically active substances, i.e., allergic and nonantigenic ways of histamine liberation and activation of the complement system.     

Acute blood neutrophilia induced by short-term compost dust exposure in previously unexposed healthy individuals

Objectives: Systemic effects of organic dust inhalation have been described in farming environments. The purpose of this study was to examine whether a single exposure at a biowaste composting facility could also exert systemic effects in healthy volunteers not previously exposed to organic dust from such facilities. Methods: Seventeen subjects (age 20–35 years) were exposed to organic dust for 2 h (exposure day) during moderate exercise; 12 of these subjects also took part in a control experiment (control day). Spirometry was performed before and immediately after the exposure. White blood cell counts and levels of tumor-necrosis factor-α (TNF-α), interleukin-1β (IL-1β) and interleukin-6 (IL-6) in peripheral blood were determined before and 3 h after exposure. Results: Exposures did not result in significant changes in lung function or blood cytokine levels. In contrast, the number and percentage of neutrophils increased during the exposure day [median (range) percent change of percentages 14 (−2; 67) %; P=0.002], but not during the control day [5 (−22; 35) %; P=0.66). Furthermore, there was a decrease in the number and percentage of eosinophils during the exposure day [−47 (−57; 0.0) %; P=0.002], whereas the change during the control day was smaller [−8 (−56; 71) %; P=0.68]. Conclusion: Short-term exposure of healthy, young subjects to organic dust from composting facilities had opposite effects on the numbers of blood neutrophils and blood eosinophils. These effects, though mild, suggest that even during a limited period of moderate work a sufficient amount of bioactive material can be deposited in the lung to elicit acute systemic alterations.     

Work related impairment of nasal function in Swedish woodwork teachers.

OBJECTIVE: To study the relation between exposure and nasal function in woodwork teachers. METHODS: 39 selected woodwork teachers employed full time and 32 control subjects (other school personnel) were examined at the beginning and at the end of a working week with symptom rating, nose and throat inspection, rhinomanometry, nasal mucociliary clearance test, and a smell identification test. During one working day of the same week climate, dust and terpene concentrations were measured in all 39 schools. RESULTS: The ventilation rate was highest in rooms with mechanical ventilation. Range of total dust (personally sampled) was 0.12-1.18 mg/m3, respirable dust 0.02-0.21 mg/m3, and terpenes (area sampled) 0.02-6.8 mg/m3. In contrast to the control subjects, the woodwork teachers had more nasal symptoms on the Thursday afternoon than on the Monday morning, especially those working in rooms without mechanical ventilation. Their mucociliary clearance worsened during the week (mean increase 4 min, P < 0.001). A small impairment of olfactory function was also found, but their rhinomanometric values did not change significantly. Nasal symptoms correlated weakly with the percentage of respirable dust in the total dust. Otherwise there were no significant dose-effect relations between measured dust or terpene concentrations and nasal tests. CONCLUSIONS: The woodwork teachers had mainly reversible nasal complaints, impaired nasal mucociliary clearance and olfactory function related to the work environment, with dust concentrations below the Swedish threshold limit value of 2 mg/m3.     

Drinking deep seawater decreases serum total and low-density lipoprotein-cholesterol in hypercholesterolemic subjects

Drinking deep seawater (DSW) with high levels of magnesium (Mg) decreased serum lipids in animal studies. Therefore the effects of drinking DSW on blood lipids and its antioxidant capacity in hypercholesterolemic subjects were investigated. DSW was first prepared by a process of filtration and reverse osmosis, and then the concentrated DSW with high levels of Mg was diluted as drinking DSW. Forty-two hypercholesterolemic volunteers were randomly divided into three groups: reverse osmotic (RO) water, DSW (Mg: 395?mg/L, hardness 1410?ppm), and magnesium-chloride fortified (MCF) water (Mg: 386?mg/L, hardness 1430?ppm). The subjects drank 1050?mL of water daily for 6 weeks, and blood samples were collected and analyzed on weeks 0, 3, and 6. Drinking DSW caused a decrease in blood total cholesterol levels and this effect was progressively enhanced with time. Serum low-density lipoprotein-cholesterol (LDL-C) was also decreased by DSW. Further, total cholesterol levels of subjects in the DSW group were significantly lower than those in the MCF water or RO water groups. Compared with week 0, the DSW group had higher blood Mg level on weeks 3 and 6, but the Mg levels were within the normal range in all three groups. DSW consumption also lowered thiobarbituric acid-reactive substances (TBARS) values in serum. In conclusion, DSW was apparently effective in reducing blood total cholesterol and LDL-C, and also in decreasing lipid peroxidation in hypercholesterolemic subjects.     

Antihistamine effect of supplemental ascorbic acid and neutrophil chemotaxis.

Renewed interest in the antihistamine action of ascorbic acid has emerged with the recently recognized immunosuppressive role of histamine. We examined the antihistamine effect of acute and chronic vitamin C (VC) administration and its effect on neutrophil chemotaxis in healthy men and women. In the chronic study, 10 subjects ingested a placebo during weeks 1, 2, 5 and 6, and 2 g/day of VC during weeks 3 and 4. Fasting blood samples were collected after the initial 2-week period (baseline) and at the end of weeks 4 and 6. Plasma ascorbate rose significantly following VC administration compared to baseline and withdrawal values. Neutrophil chemotaxis rose 19% (NS) during VC administration, and fell 30% after VC withdrawal, but these changes were not correlated to plasma ascorbate levels (r = 0.01). Chemotaxis was inversely correlated to blood histamine (r = -0.32, p = 0.045), and, compared to baseline and withdrawal values, histamine levels were depressed 38% following VC supplementation. Blood histamine and neutrophil chemotaxis did not change 4 hours following a single 2 g dose of ascorbic acid, although plasma ascorbate rose 150%. These data indicate that VC may indirectly enhance chemotaxis by detoxifying histamine in vivo.     

Respiratory response to endotoxin and dust predicts evidence of inflammatory response in volunteers in a swine barn

BACKGROUND: It has been shown that exposure in intense exposure in swine barn facilities is associated with increased respiratory symptoms and reduction in pulmonary functions. This study investigated if systemic response could be predicted by FEV(1) response following swine barn exposure. METHODS: Na?ve males were tested at baseline, low and high endotoxin and dust levels. Subjects were classified as "more responsive" (n = 9) or "less responsive" (n = 11) based on FEV(1) reduction following high endotoxin exposure. Health measures included pulmonary function testing, blood samples and nasal lavage. Environmental samples were collected from the barn. RESULTS: White blood cells and blood lymphocytes at low exposure were significantly greater in those who were "more responsive" compared to those who were "less responsive". There was a significant increase in blood lymphocytes, serum IL6, total nasal lavage cells and nasal IL8 at high exposure among "more responsive" subjects compared to "less responsive" subjects. CONCLUSIONS: Respiratory response to high-level endotoxin and dust exposure predicts evidence of inflammatory response throughout a range of endotoxin and dust exposures.     

An environmental and respiratory health survey of workers in a grain mill in the Johannesburg area,South Africa

A respiratory health survey was conducted in a grain mill and the relationship of health indicators to quantitative measures of airborne dust, fungal, and bacterial contamination was examined. Respiratory symptoms were more prevalent in the high dust exposure categories; lung function levels were also higher in the high dust exposure categories, consistent with a “healthy” worker effect. Workers in the three higher dust exposure categories showed either no change or a decrease in lung function over the working week, while workers in the low exposure category demonstrated an improvement in lung function over the working week. Total dust and microbiological (fungal and bacterial) load were found to be significantly related to each other, and the relationship of microbiological load to lung function level and changes over the working week were similar to those found for total dust © 1993 Wiley-Liss, Inc.     

Risks to children from exposure to lead in air during remedial or removal activities at Superfund sites: a case study of the RSR lead smelter Superfund site

Superfund sites that are contaminated with lead and undergoing remedial action generate lead-enriched dust that can be released into the air. Activities that can emit lead-enriched dust include demolition of lead smelter buildings, stacks, and baghouses; on-site traffic of heavy construction vehicles; and excavation of soil. Typically, air monitoring stations are placed around the perimeter of a site of an ongoing remediation to monitor air lead concentrations that might result from site emissions. The National Ambient Air Quality (NAAQ) standard, established in 1978 to be a quarterly average of 1.5 microg/m(3), is often used as a trigger level for corrective action to reduce emissions. This study explored modeling approaches for assessing potential risks to children from air lead emissions from the RSR Superfund site in West Dallas, TX, during demolition and removal of a smelter facility. The EPA Integrated Exposure Uptake Biokinetic (IEUBK) model and the International Commission of Radiologic Protection (ICRP) lead model were used to simulate blood lead concentrations in children, based on monitored air lead concentrations. Although air lead concentrations at monitoring stations located in the downwind community intermittently exceeded the NAAQ standard, both models indicated that exposures to children in the community areas did not pose a significant long-term or acute risk. Long-term risk was defined as greater than 5% probability of a child having a long-term blood lead concentration that exceeded 10 microg/dl, which is the CDC and the EPA blood lead concern level. Short-term or acute risk was defined as greater than 5% probability of a child having a blood lead concentration on any given day that exceeded 20 microg/dl, which is the CDC trigger level for medical evaluation (this is not intended to imply that 20 microg/dl is a threshold for health effects in children exposed acutely to airborne lead). The estimated potential long-term and short-term exposures at the downwind West Dallas community did not result in more than 5% of children exceeding the target blood lead levels. The models were also used to estimate air lead levels for short-term and long-term exposures that would not exceed specified levels of risk (risk-based concentrations, RBCs). RBCs were derived for various daily exposure durations (3 or 8 h/day) and frequencies (1-7 days/week). RBCs based on the ICRP model ranged from 0.3 (7 days/week, 8 h/day) to 4.4 microg/m(3) (1 day/week, 3 h/day) for long-term exposures and were lower than those based on the IEUBK model. For short-term exposures, the RBCs ranged from 3.5 to 29.0 microg/m(3). Recontamination of remediated residential yards from deposition of air lead emitted during remedial activities at the RSR Superfund site was also examined. The predicted increase in soil concentration due to lead deposition at the monitoring station, which represented the community at large, was 3.0 mg/kg. This potential increase in soil lead concentration was insignificant, less than 1% increase, when compared to the clean-up level of 500 mg/kg developed for residential yards at the site.     

What symptoms predict the bronchial response to histamine? Evaluation in a community survey of the bronchial symptoms questionnaire (1984) of the International Union Against Tuberculosis and Lung Disease

A questionnaire developed by the International Union against Tuberculosis and Lung Disease (IUATLD) to assess bronchial symptoms has been tested for its ability to predict the bronchial response to histamine in adults aged 18-64 years living in two areas of southern England. A number of questions were found to be independently associated with increased reactivity in the first randomly selected half of the subjects. These symptoms included wheeze, waking at night with shortness of breath, tightness in the chest or shortness of breath when exposed to animals, dust or feathers and the non-specific symptom of persistent problems with breathing. A predictive score based on these symptoms was more sensitive and only slightly less specific than the question on wheeze alone in predicting the response to histamine in the second half of the subjects. Questions about asthma though more specific were considerably less sensitive than either. Symptoms did not differentiate between reactivity associated with positive skin tests and that associated with smoking.     

Serum lipoprotein(a) changes in acute myocardial infarction.

BACKGROUND: A strong correlation between high serum Lp(a) levels, a genetic modification of cholesterol-low density lipoproteins (c-LDL), and increased coronary heart disease rate has been found. Transient increased serum levels of this lipoprotein during acute myocardial infarction (AMI) and surgical interventions have been found. METHODS: Experimental design: we assessed complete lipidic pattern in a study series composed of 19 patients with AMI. We also evaluated the changes of Lp(a) serum levels within the first week of the disease in order to assess whether a correlation between this parameter and extent of necrotic myocardial area is present. Patients: study series was made up of 19 patients (13 males, 6 females; mean age 57.94+/-10.7 years) with AMI compared to 25 control subjects (12 males and 13 females; mean age 51.12+/-15.34 years). Measures: we also withdrew a blood sample on days 1, 3 and 7 from the onset of the AMI. On the first day we evaluated the serum levels of the following parameters: glycaemia, azotemia, creatininemia, urycaemia, total cholesterol, high density lipoprotein cholesterol (c-HDL), low density lipoprotein cholesterol (c-LDL), triglycerides, fibrinogen, creatinphosphokinase, aspartate aminotranspherase, thromboplastine time and prothrombinic activity. Lp(a) has been evaluated on day 1, 3 and 7 and after 6 months from AMI. We performed an ultrasound scanning (US) of the heart in day 7 for evaluation of the extent of necrotic myocardial area by observation of "segmental kinetic area". RESULTS: Mean basal Lp(a) serum level was 28.94+/-29.78 mg/dl (as median 17), (normal values 0 to 25 mg/dl). This value was not changed on day 3 (mean 29.47+/-30.46 mg/dl, median 18), while significantly increased on day 7 (39.84+/-42.77, median 26, p=0.05). Spearman's rank correlation test showed a strong correlation between the increase of Lp(a) serum levels on day 7 and extent of necrotic myocardial area (r=0.696, p=0.001). CONCLUSIONS: The positive correlation between mean Lp(a) values on day 1 and 7, and the size of the necrotic area, suggest that Lp(a) has an atherogenic and prothrombotic role. Moreover, elevated Lp(a) values were related to greater tissue damage. We believe that periodical determination of Lp(a) values in subjects with coronary disease is useful in order to predict further acute vascular events.     

Exposure to grain dust and changes in lung function.

Respiratory symptoms and lung function were assessed in 41 seasonal grain handlers and related to duration of employment and level of exposure to grain dust. Ten public works department employees, not exposed to grain dust, were examined during the same period. Respiratory symptoms, forced expired volume in one second (FEV1), and bronchial responsiveness (dose of methacholine provoking a 20% fall in FEV1-PD20) were assessed before starting work and at weekly intervals during a period of employment lasting up to four weeks. Two atopic grainhandlers with pronounced bronchial hyperresponsiveness (PD20 less than 1 mumol) and a history of asthma withdrew from the study within two weeks because they developed severe asthma. Respiratory symptoms were more frequent and more often attributed to work in the grainhandlers than in the non-exposed subjects. In the grainhandlers the FEV1 decreased by a mean (95% confidence intervals) of 321 ml (198-444) (p less than 0.05) and the mean (95% confidence interval) PD20 decreased from 20.6 mumol (10.3-41.2) to 6.0 mumol (2.8-12.5) (p less than 0.05) after one week of work. Over the next three weeks the mean FEV1 returned towards the prestudy values. The mean PD20, however, remained significantly lower than the initial value. The mean FEV1 and PD20 did not change significantly in the non-exposed subjects. The frequency of symptoms and decreases in FEV1 were greater in grainhandlers when working in jobs where total exposure to dust was greater than 20 mg/m3 than when working in jobs where it was less than 10 mg/m3. The results indicate that occupational exposure to grain dust results in respiratory symptoms and changes in lung function, including increased airway responsiveness, within the first week of exposure to grain dust at work. These changes appear to be determined by the degree of dust exposure and suggest a direct effect of grain dust on the lung in these subjects.     

Differential pattern of human blood neutrophil activation after stimulation with organic dust in vitro and in vivo

OBJECTIVE: To study activation of blood neutrophils in subjects after in vitro and in vivo stimulation. METHODS: Blood from healthy volunteers was collected before and after their exposure to organic dust in a pig farm. Surface markers of neutrophil activation were analyzed by flow cytometry. RESULTS: In vivo, there was a diurnal variation in basal levels of CD11b. Swine dust exposure increased the number of blood neutrophils and the levels of myeloperoxidase without effects on CD11b or Cys-X-Cys receptor 1 (CXCR-1) expression. However, a positive correlation between changes of myeloperoxidase and CD11b expression was observed. In vitro, N-formyl-methionyl-leucyl-phenylalanine (fMLP), lipopolysaccharide (LPS), leukotriene (LT)B4, LTD4, and swine dust stimulated the expression of CD11b. fMLP, LPS, and LTB4 diminished the expression of CXCR-1. CONCLUSIONS: Exposure to swine dust in vitro activated neutrophils and inhalation of swine dust caused neutrophilia.     

Exposure to grain dust and changes in lung function

Respiratory symptoms and lung function were assessed in 41 seasonal grain handlers and related to duration of employment and level of exposure to grain dust. Ten public works department employees, not exposed to grain dust, were examined during the same period. Respiratory symptoms, forced expired volume in one second (FEV1), and bronchial responsiveness (dose of methacholine provoking a 20% fall in FEV1-PD20) were assessed before starting work and at weekly intervals during a period of employment lasting up to four weeks. Two atopic grainhandlers with pronounced bronchial hyperresponsiveness (PD20 less than 1 mumol) and a history of asthma withdrew from the study within two weeks because they developed severe asthma. Respiratory symptoms were more frequent and more often attributed to work in the grainhandlers than in the non-exposed subjects. In the grainhandlers the FEV1 decreased by a mean (95% confidence intervals) of 321 ml (198-444) (p less than 0.05) and the mean (95% confidence interval) PD20 decreased from 20.6 mumol (10.3-41.2) to 6.0 mumol (2.8-12.5) (p less than 0.05) after one week of work. Over the next three weeks the mean FEV1 returned towards the prestudy values. The mean PD20, however, remained significantly lower than the initial value. The mean FEV1 and PD20 did not change significantly in the non-exposed subjects. The frequency of symptoms and decreases in FEV1 were greater in grainhandlers when working in jobs where total exposure to dust was greater than 20 mg/m3 than when working in jobs where it was less than 10 mg/m3. The results indicate that occupational exposure to grain dust results in respiratory symptoms and changes in lung function, including increased airway responsiveness, within the first week of exposure to grain dust at work. These changes appear to be determined by the degree of dust exposure and suggest a direct effect of grain dust on the lung in these subjects.     

Reactions of healthy persons and persons suffering from allergic rhinitis when exposed to office dust

OBJECTIVES: Reactions to airborne office dust among healthy subjects and subjects suffering from allergic rhinitis were investigated. METHODS: Twelve healthy and 11 subjects suffering from allergic rhinitis were exposed to clean air [17 (SD 2) microg/m3] and office dust [439 (SD 68) microg/m3] for 245 minutes. The effect measurements included subjective sensations (questionnaire and potentiometer ratings), mood scale, peak flow, bronchial provocation with histamine using forced expiratory volume in 1 second as the effect measure, nasal mucosal swelling, tear film stability, epithelial damage, foam formation in the eye canthus, threshold for eye irritation with carbon dioxide, eye redness, cellular content of conjunctival fluid, and an addition test for distraction. As many investigations were made and as many statistical analyses (including subgroup analyses) were carried out, the risk of mass significance appeared. This problem was dealt with using the Bonferroni correction for multiple significance tests. RESULTS: The mean ratings of the potentiometer were higher (the subjects showed more irritation) during the dust exposure. The objective investigations showed only indications of effects of dust exposure, and some of the indications were in biologically unexplainable directions. No difference in the reactions to dust was observed between the healthy subjects and the subjects suffering from allergic rhinitis. CONCLUSIONS: Dust does not seem to have objective or subjective effects on humans, as only indications of dust effects were found. Subjects suffering from allergic rhinitis do not appear to be a risk group in relation to dust exposure.     

VENTILATORY CAPACITY ON EXPOSURE TO JUTE DUST AND THE RELEVANCE OF PRODUCTIVE COUGH AND SMOKING TO THE RESPONSE

The ventilatory capacity of 46 men exposed to jute dust in the manufacture of felt and wadding was estimated at the beginning and end of shifts on the first and last days of a working week. A smoking history was obtained from all subjects, and for those speaking English a more detailed questionnaire on respiratory symptoms was completed. Each man was also instructed to cough under observation, and a loose cough, as judged by ear or by production of a sputum specimen was recorded as productive. A significant mean decrease in forced expiratory volume at one second was observed in the series as a whole on the first day at work, but no significant change was found over the final day nor over the entire week. Closer analysis reveals that this decrease was largely confined to those with a productive cough on request, and to those who smoked, most of the former group being smokers. In these groups the decrease observed on the first day tended to persist throughout the week. Insofar as those who smoked, and particularly those who had a productive cough, tended to have a lower F.E.V._1·0, expressed either in absolute units or as a percentage of the forced vital capacity, the men with the greater initial impairment of ventilatory capacity showed the more significant decreases on exposure to dust. Evidence is produced to suggest that the sign of productive cough defines better than the history a group with a lower ventilatory capacity and a greater tendency to react to inhaled irritants.     

Alterations of serum brain-derived neurotrophic factor levels in early alcohol withdrawal

AIMS: Alcohol withdrawal-enhanced neurotoxicity contributes to the addictive process. Brain-derived neurotrophic factor (BDNF) plays an important role in neuronal plasticity and learning. In this study, we explored the changes of serum BDNF levels in alcoholic patients at baseline and after one-week alcohol withdrawal. METHODS: Twenty-five alcoholic patients were admitted for alcohol detoxification treatment, and 22 healthy control subjects were also enrolled. We collected blood samples of the patient group on the first and seventh day of alcohol withdrawal, and measured serum BDNF level with sandwich enzyme-linked immunosorbent assay. The severity of withdrawal symptoms was evaluated by the Clinical Institute Withdrawal Assessment-Alcohol, Revised every eight hours. RESULTS: Serum BDNF levels did not differ significantly between alcoholic patients and control subjects. But BDNF levels were found to be significantly increased one week after alcohol withdrawal (from 13.9 +/- 3.8 ng/ml to 15.4 +/- 3.8 ng/ml, P = 0.03). A significant positive correlation was found between baseline BDNF level and baseline withdrawal severity (r = 0.45, P = 0.03). CONCLUSIONS: The present study suggests that elevated serum BDNF levels were found in early alcohol withdrawal, implying that BDNF may involve in neuroadaptation during the period.