The interaction of oxygen with TiC(001): Photoemission and first-principles studies

High-resolution photoemission and first-principles density-functional slab calculations were used to study the interaction of oxygen with a TiC(001) surface. Atomic oxygen is present on the TiC(001) substrate after small doses of O(2) at room temperature. A big positive shift (1.5-1.8 eV) was detected for the C 1s core level. These photoemission studies suggest the existence of strong O<-->C interactions. A phenomenon corroborated by the results of first-principles calculations, which show a CTiTi hollow as the most stable site for the adsorption of O. Ti and C atoms are involved in the adsorption and dissociation of the O(2) molecule. In general, the bond between O and the TiC(001) surface contains a large degree of ionic character. The carbide-->O charge transfer is substantial even at high coverages (>0.5 ML) of oxygen. At 500 K and large doses of O(2), oxidation of the carbide surface occurs with the removal of C and formation of titanium oxides. There is an activation barrier for the exchange of Ti-C and Ti-O bonds which is overcome only by the formation of C-C or C-O bonds on the surface. The mechanism for the removal of a C atom as CO gas involves a minimum of two O adatoms, and three O adatoms are required for the formation of CO(2) gas. Due to the high stability of TiC, an O adatom alone cannot induce the generation of a C vacancy in a flat TiC(001) surface.

Highly thermostable amylase and pullulanase of the extreme thermophilic eubacterium Rhodothermus marinus: production and partial characterization

Five strains of the extreme thermophilic Rhodothermus marinus were screened for the production of amylolytic and pullulytic activities. The culture medium for the selected strain, R. marinus ITI 990, was optimized using central composite designs for enhanced enzyme production. The optimized medium containing 1.5 gl(-1) of maltose and 8.3 gl(-1) of yeast extract yielded amylase, pullulanase and alpha-glucosidase activities of 45, 33 and 2.1 nkatml(-1), respectively. Among the various carbon sources tested, maltose was most effective for the formation of these enzymes, followed by soluble maize starch, glycogen and pullulan. The crude amylase and pullulanase showed maximum activities at pH 6.5-7.0, and 85 and 80 degrees C, respectively. At 85 degrees C amylase and pullulanase had half lives of 3 h and 30 min, respectively.

[Priapism]

Priapism is a rare disease, characterized by a prolonged erection unrelated to sexual stimulus or desire. There are two distinct types of priapism with different etiologies, pathophysiology, treatment and complications. A better understanding of these two clinical entities brought about, in recent years, some progress in their treatment. The authors make a retrospective analysis of the 17 cases of priapism diagnosed in this centre in the last twelve years. From this experience they review the standard approach to this disease, both diagnostic and therapeutic.

Production of laccase by a newly isolated strain of Trametes modesta

The effects of the carbon and nitrogen sources, initial pH and incubation temperature on laccase production by Trametes modesta were evaluated using the one-factor-at-a-time method. The final optimisation was done using a central composite design resulting in a four-fold increase of the laccase activity to 178 nkat ml(-1). Response-surface analysis showed that 7.34 g l(-1) wheat bran, 0.87 g l(-1) glucose, 2.9 g l(-1) yeast extract, 0.25 g l(-1) ammonium chloride, an initial pH of 6.95 and an incubation temperature of 30.26 degrees C were the optimal conditions for laccase production. Laccase produced by T. modesta was fully active at pH 4 and at 50 degrees C. The laccase was very stable at pH 4.5 and at 40 degrees C but half-lives decreased to 120 and 125 min at higher temperature (60 degrees C) and lower pH (pH 3).

[Urolithiasis and renal colic. Therapeutic approach in urology]

Renal colic is one of the most common pathologies found in our emergency services. Although a source of great pain and apprehension, most of the episodes do not need a specialised approach. The authors present a general overview in the proposed management of kidney lithiasis, including both recommendations for a conservative, expectant or prophylactic treatment, and recommendations and different techniques for urological intervention.

First account on the larval biology of a Litomosoides filaria, from a bat

Litomosoides filariae are parasites of unrelated groups of hosts, including bats, marsupials, ancient and modern rodents. The four life cycles to-date elucidated, develop in terrestrial mammals and, at least experimentally, in the mite Ornithonyssus bacoti. A batch of mites was fed on an infected bat, Artibeus jamaicensis captured in Costa Rica, and 18 days later one infective larva was recovered. Its morphology was similar to that of other Litomosoides species, with the characteristic long buccal capsule. These first accounts on the larval biology of Litomosoides from Microchiroptera confirm the unity of the genus which supports the view that it has passed from one group of hosts to another by means of captures.

The health of the workers in a rapidly developing country: effects of occupational exposure to noise and heat

Occupational hygiene and safety have not been high on the agenda of industrial management in developing countries for a variety of reasons. This cross-sectional study was undertaken to assess the exposure to noise and heat, and to study the level of occupational hygiene practiced, at a foundry in a rapidly developing country (Dubai, United Arab Emirates). Audiometry, muscle cramps and visual acuity were measured in workers at a foundry and compared with the results from workers at a soft-drink bottling plant. Thermal stress, relative humidity, ventilation, illumination and noise levels were measured at different work units at the foundry and at the soft-drink bottling factory. Thermal stress index was high while relative humidity and ventilation were low at the foundry compared with the bottling plant. Noise levels were also high at the foundry, exceeding 90 dB at almost all work units except the fabrication workshop. Mild or moderate visual defects were observed among 31% of foundry workers, compared with 19% of the bottling plant workers.Muscle cramps were reported by 30% of all workers at the foundry, compared with 5% at the bottling plant. Visual disability was the highest among furnace operators and fabricators. Mean hearing disability was 8.69 +/- 1.08% among foundry workers, compared with 4.56 +/- 0.82% among bottling plant workers. The high thermal stress, noise levels and exposure to non-ionizing radiations at the foundry might have contributed to the higher frequency of muscle cramps and the greater hearing and visual disabilities, respectively, among these workers. Non-use of personal protective equipment and poor occupational hygiene and safety measures were also seen to affect eye and ear health adversely among the workers at the foundry.

Current role of simplified upper tract approach in the surgical treatment of ectopic ureteroceles: a single centre's experience

OBJECTIVE

Despite renewed interest in either endoscopic decompression or complete reconstruction as primary approaches in ectopic ureterocele's (EU's) treatment, we advocate that a simplified upper tract approach is an optimal choice in a large subset of these patients. We review our surgical results to evaluate the effectiveness of different surgical procedures used in the treatment of EU, based on an individualized approach.

PATIENTS AND METHODS

We retrospectively analysed all patients with EU and without previous treatment (n = 59) operated in this centre between the years 1991 and 2000. This disorder was bilateral in three patients (62 EU) and associated with duplex ureters in 60 cases. Vesicoureteral reflux (VUR) was diagnosed pre-operatively in 49.1% of patients. Treatment and choice of procedure was based on patients' age, clinical manifestations, associated abnormalities and function of the ureterocele-bearing moiety. Patients were divided in three separate groups according to the initial surgical approach. Group 1-11 patients submitted to endoscopic puncture (six urgent ureterocele decompression, four infants with obstruction of a functional ureterocele-bearing moiety and another with both lower pole ureter and mild bladder outflow obstruction). Group 2-30 patients (31 EU) submitted to a simplified upper tract approach--pyeloureterostomy (1), heminephrectomy (29) and nephrectomy (1) (all patients but one with non-viable renal segments; VUR, grade < or = III, present in six cases). Group 3-18 patients (20 EU) submitted to complete primary reconstruction (all patients with high-grade and/or contralateral reflux, with or without function of the ureterocele-bearing moiety). Success (clinically asymptomatic patients, without obstruction or VUR) and complication rates from the different approaches were analysed. For statistical evaluation, we used Fisher's exact test with p < or = 0.05 considered significant.

RESULTS

The success rate of endoscopic treatment, simplified upper tract approach and complete reconstruction were 18.2%, 80% and 83.3%, respectively. Major complications occurred in two patients from group 3.

CONCLUSION

Endoscopic puncture is our first option when immediate ureterocele decompression is required, although it seldom affords definitive treatment. Complete primary reconstruction is necessary in complex cases. Cure rates are high but there is a potential risk for serious complications. A simplified upper tract approach is curative in most patients without associated reflux. Heminephrectomy remains our first choice in a large subset of patients with non-viable or hypofunctional renal segments and without high-grade reflux.

Decolorization of textile dyes by laccases from a newly isolated strain of Trametes modesta

Four ligninolytic fungi, Trametes modesta, Trametes hirsuta, Trametes versicolor and Sclerotium rolfsii, were compared for their ability to produce laccases. The fungal laccases were screened for their ability to decolorize eight synthetic dyes (anthraquinone, azo, indigo and triarylmethane). The decolorization rate depended both on the source of the enzyme preparation and on the structure of the dye. Based on laccase production and dye decolorizing ability, T. modesta was selected for further studies. All the tested dyes were decolorized by the T. modesta laccase most efficiently under acid conditions (pH 3-6) but the optimum pH for decolorization of the individual dye varied. The decolorization rate of this laccase increased with the rise in temperature to 50-60 degrees C. The decolorization efficiency of T. modesta laccase was improved remarkably in the presence of mediators like 1-hydroxybenzotriazole and 2-methoxyphenothiazine.

Dust exposure and impairment of lung function at a small iron foundry in a rapidly developing country

OBJECTIVES

A cross sectional prospective study was carried out among iron foundry workers (exposed) and soft drink bottling and supply company workers (unexposed) to assess their occupational exposure to ambient respiratory dust in their work environment and its effect on their lung function profile.

PARTICIPANTS

Lung function was measured in 81 exposed and 113 unexposed workers. Personal respirable dust concentrations were measured for all the exposed and the unexposed workers. Information on respiratory signs and symptoms was also collected from the participants.

RESULTS

Among the exposed workers, midexpiratory flow (FEF25-75), forced expiratory volume in 1 second (FEV1), peak expiratory flow (PEF), FEV1/FVC, and FEV1/VC ratios were significantly lower whereas the vital capacity (VC) and forced vital capacity (FVC) were non-significantly higher. Job at the iron foundry was a significant predictor of lung function. Exposure to high concentration of respirable dust at the iron foundry was also a significant predictor. Workers working in high exposure areas (general works, furnace, continuous casting areas, and fabrication workshop) had lower lung function values than workers in medium and low exposure areas. Smoking did not enhance the effects of exposure to dust on lung function.

CONCLUSIONS

Exposure to respirable dust was higher among the iron foundry workers; and among these, general, furnace, rolling mill, and fabrication workers had higher exposures to dust than did workers in continuous casting, the mechanical workshop, and the bottling plant. Job type and exposure to dust were significant predictors of lung function. Implementation of industrial hygiene and proper and efficient use of personal protection equipment while at work could help to protect the respiratory health of industrial workers.

Respiratory illnesses and ventilatory function among workers at a cement factory in a rapidly developing country

Chronic exposure to Portland cement dust has been reported to lead to a greater prevalence of chronic respiratory symptoms and a reduction of ventilatory capacity. The seriousness of pulmonary function impairment and respiratory disease has not been consistently associated with the degree of exposure. Regular use of appropriate personal protective equipment, if available at the worksite, could protect cement workers from adverse respiratory health effects. For a variety of reasons, industrial workers in rapidly developing countries do not adequately protect themselves through personal protective equipment. This study explores the prevalence of chronic respiratory symptoms and ventilatory function among cement workers and the practice of use of personal protective equipment at work. An interviewer-administered questionnaire was used to collect information on sociodemographic characteristics, smoking profile and history of respiratory health among workers at a Portland cement plant (exposed) and workers occupationally unexposed to dust, fumes and gases (unexposed). Pulmonary function was assessed and pulmonary function impairment was calculated for the exposed and the unexposed workers. A higher percentage of the exposed workers reported recurrent and prolonged cough (30%), phlegm (25%), wheeze (8%), dyspnoea (21%), bronchitis (13%), sinusitis (27%), shortness of breath (8%) and bronchial asthma (6%). Among the unexposed, prevalences of these symptoms were 10, 5, 3, 5, 4, 11, 4 and 3%, respectively. Ventilatory function (VC, FVC, FEV(1), FEV(1)/VC, FEV(1)/FVC and PEF) was significantly lower in the exposed workers compared with unexposed workers. These differences could not be explained by age, body mass index (BMI) or pack-years smoked. Ventilatory function impairment, as measured by FEV(1)/FVC, showed that 36% of the exposed workers had some ventilatory function impairment compared with 10% of those unexposed. Certain jobs with greater exposure to cement dust had lower ventilatory function compared with others among the exposed workers. It was concluded that adverse respiratory health effects (increased frequency of respiratory symptoms and decreased ventilatory function) observed among cement workers could not be explained by age, BMI and smoking, and were probably caused by exposure to cement dust.

Optimisation of culture medium and conditions for alpha-l-Arabinofuranosidase production by the extreme thermophilic eubacterium Rhodothermus marinus

The culture medium for Rhodothermus marinus was optimised on a shake-flask scale by using statistical factorial designs for enhanced production of a highly thermostable alpha-L-arabinofuranosidase (AFase). The medium containing 3.6 g/l birch wood xylan and 8.2 g/l yeast extract yielded a maximum of 110 nkat/ml AFase activity together with 125 nkat/ml xylanase and 65 nkat/ml beta-xylosidase activity. In addition, low levels of beta-mannanase (30 nkat/ml), alpha-galactosidase (0.2 nkat/ml), beta-galactosidase (0.3 nkat/ml), endoglucanase (5 nkat/ml) and beta-glucosidase (30 nkat/ml) were detected in the culture filtrate. Among the various carbon sources tested, birchwood xylan was most effective for the formation of AFase and xylanase activities, followed by oat spelt and beechwood xylans, and xylan-rich lignocelluoses (e.g., starch-free sugar beet pulp and wheat bran). Constitutive levels of enzyme activities were detected when the bacterium was grown on other polysaccharides and low-molecular-weight carbohydrates. A fermentation in a 5-l fermenter (3-l working volume) using the optimised medium yielded 60 nkat/ml AFase associated with 65 nkat/ml xylanase and 35 nkat/ml beta-xylosidase activities. The crude AFase displayed optimal activity between pH 5.5 and 7 and at 85 degrees C. It had half-lives of 8.3 h at 85 degrees C and 17 min at 90 degrees C. It showed high stability between pH 5 and 9 (24 h at 65 degrees C). The combined use of AFase-rich xylanase and mannanase from R. marinus in the prebleaching of softwood kraft pulp gave a brightness increase of 1.8% ISO. To our knowledge, this is the first report on the production of a high AFase activity by an extreme thermophilic bacterium and this enzyme is the most thermostable AFase reported so far.

Simultaneous detection of different glycosidase activities by 19F NMR spectroscopy

A fast method for the simultaneous detection of different glycosidolytic activities in commercially available enzyme preparations and crude culture filtrates was found in using, as substrate, a mixture of different glycosyl fluorides and 19F NMR spectroscopy as a screening technique. Accompanying studies regarding the hydrolytic stability of these fluorides in various buffer systems, as well as conditions of their long-term storage, were carried out. A simple procedure for the preparation of beta-D-mannopyranosyl fluoride in gram quantities is given.

Thermolabile xylanase of the Antarctic yeast Cryptococcus adeliae: production and properties

Xylanase production by the Antarctic psychrophilic yeast Cryptococcus adeliae was increased 4.3 fold by optimizing the culture medium composition using statistical designs. The optimized medium containing 24.2 g l(-1) xylan and 10.2 g l(-1) yeast extract and having an initial pH of 7.5 yielded xylanase activity at 400 nkat (nanokatal) ml(-1) after 168-h shake culture at 4 degrees C. In addition, very little endoglucanase, beta-mannanase, beta-xylosidase, beta-glucosidase, alpha-L-arabinofuranosidase, and no filter paper cellulase activities were detected. Among 12 carbon sources tested, maximum xylanase activity was induced by xylan, followed by lignocelluloses such as steamed wheat straw and alkali-treated bagasse. The level of enzyme activity produced on other carbon sources appeared to be constitutive. Among the complex organic nitrogen sources tested, the xylanase activity was most enhanced by yeast extract, followed by soymeal, Pharmamedia (cotton seed protein), and Alburex (potato protein). A batch culture at 10 degrees C in a 5-1 fermenter (3.5-1 working volume) using the optimized medium gave 385 nkat at 111 h of cultivation. The crude xylanase showed optimal activity at pH 5.0-5.5 and good stability at pH 4-9 (21 h at 4 degrees C). Although the enzyme was maximally active at 45 degrees - 50 degrees C, it appeared very thermolabile, showing a half-life of 78 min at 35 degrees C. At 40 degrees - 50 degrees C, it lost 71%-95% activity within 5 min. This is the first report on the production as well as on the properties of thermolabile xylanase produced by an Antarctic yeast.

Simultaneous production of high activities of thermostable endoglucanase and beta-glucosidase by the wild thermophilic fungus Thermoascus aurantiacus

The culture-medium composition was optimised, on a shake-flask scale, for simultaneous production of high activities of endoglucanase and beta-glucosidase by Thermoascus aurantiacus using statistical factorial designs. The optimised medium containing 40.2 g l(-1) Solka Floc as the carbon source and 9 g l(-1) soymeal as the organic nitrogen source yielded 1130 nkat ml(-1) endoglucanase and 116 nkat ml(-1) beta-glucosidase activities after 264 h as shake cultures. In addition, good levels of beta-xylanase (3479 nkat ml(-1)) and low levels of filter-paper cellulase, beta-xylosidase, alpha-L-arabinofuranosidase, beta-mannanase, beta-mannosidase, alpha-galactosidase and beta-galactosidase were detected. Batch fermentation in a 5-1 laboratory fermentor using the optimised medium allowed the production of 940 nkat ml(-1) endoglucanase and 102 nkat ml(-1) beta-glucosidase in 192 h. Endoglucanase and beta-glucosidase showed optimum activity at pH 4.5 and pH 5, respectively, and they displayed optimum activity at 75 degrees C. Endoglucanase and beta-glucosidase showed good stability at pH values 4-8 and 4-7, respectively, after a prolonged incubation (48 h at 50 degrees C). Endoglucanase had half-lives of 98 h at 70 degrees C and 4.1 h at 75 degrees C, while beta-glucosidase had half-lives of 23.5 h at 70 degrees C and 1.7 h at 75 degrees C. Alkali-treated bagasse, steam-treated wheat straw, Solka floc and Sigmacell 50 were 66, 48.5, 33.5 and 14.4% hydrolysed by a crude enzyme complex of T. aurantiacus in 50 h.

Nutritional status and mortality of refugee and resident children in a non-camp setting during conflict: follow up study in Guinea-Bissau

OBJECTIVE

To study the effects on children of humanitarian aid agencies restricting help to refugee families (internally displaced people).

DESIGN

Follow up study of 3 months.

SETTING

Prabis peninsular outside Bissau, the capital of Guinea-Bissau, which has functioned as a refugee area for internally displaced people in the ongoing war, and the study area of the Bandim health project in Bissau.

PARTICIPANTS

422 children aged 9-23 months in 30 clusters.

MAIN OUTCOME MEASURES

Mid-upper arm circumference and survival in relation to residence status.

RESULTS

During the refugee situation all children deteriorated nutritionally, and mortality was high (3.0% in a 6 week period). Rice consumption was higher in families resident in Prabis than in refugees from Bissau but there was no difference in food expenditure. Nutritional status, measured by mid- upper arm circumference, was not associated with rice consumption levels in the family, and the decline in circumference was significantly worse for resident than for refugee children; the mid-upper arm circumference of refugee children increased faster than that of resident children. For resident children, mortality was 4.5 times higher (95% confidence interval 1.1 to 30.0) than for refugee children. Mortality for both resident and refugee children was 7.2 times higher (1.3 to 133.9) during the refugee's stay in Prabis compared with the period after the departure of the refugees.

CONCLUSION

In a non-camp setting, residents may be more malnourished and have higher mortality than refugees. Major improvements in nutritional status and a reduction in mortality occurred in resident and refugee children as soon as refugees returned home despite the fact that there was no improvement in food availability.

Production of urokinase by HT 1080 human kidney cell line

Studies were carried out in T-flasks and bioreactor to produce urokinase enzyme using HT 1080 human kidney cell line. While growing the cell line it has been observed that the lag phase is reduced considerably in the bioreactor as compared to T-flask culture. The HT 1080 cell adhesion rate and urokinase production were observed to be the function of serum concentration in the medium. The maximum urokinase activity of 3.1 x 10(-4) unit ml(-1) was achieved in the bioreactor at around 65 h of batch culture. Since HT 1080 is an anchorage dependent cell line, therefore, the hydrodynamic effects on the cell line were investigated.

Screening of army soldiers for Wuchereria bancrofti infection in the metropolitan Recife region, Brazil: implications for epidemiological surveillance

Between 1989 and 1995, blood surveys were performed for Wuchereria bancrofti infection in several barracks of the Brazilian army in the metropolitan Recife region. For initial screening, 60 microliters of capillary blood were examined for microfilaria. All men who tested positive had microfilaria quantified by filtration of venous blood through a polycarbonate membrane. Of 23,773 men screened, 585 (2.5%) had microfilaria (mf). Microfilarial density ranged from < 1-8706 mf/ml of blood. Thirteen individuals had ultra-low microfilarial densities (1 mf/11 ml of blood). Characterization of 174 autochthonous cases made it possible to map 8 new districts in 4 cities within metropolitan Recife region where transmission of W. bancrofti was previously unknown. Routine screening of soldiers in the military may provide important surveillance data for national programmes to eliminate transmission of W. bancrofti.

Hepatic injury and disturbed amino acid metabolism in mice following prolonged exposure to organophosphorus pesticides

Chronic occupational exposure to organophosphorus and carbamate-type pesticides significantly inhibits acetylcholinesterase activity and causes morbidity. This study on mice was designed to evaluate their amino profile and to identify signs of hepatic dysfunction following their chronic exposure to mixtures of organophosphorus pesticides. Laboratory mice were exposed to a formulated mixture of the six organophosphorus pesticides (Dimethoate, Chlorpyrifos, Profenofos, Pirimiphos methyl, Triazophos and Dimethoate) most commonly used in agriculture in this region of the Middle East. Doses (10% of LD50 of the mixture) were given once a week by gavage in corn oil for 7 weeks; the control group was given only corn oil. At the end of the exposure period, mice were culled and blood samples were collected to determine erythrocyte acetylcholinesterase activity, biochemical markers of liver function and concentrations of serum amino acids. Erythrocyte acetylcholinesterase activity and total serum proteins decreased significantly in the exposed group. Serum concentrations of alanine aminotransferase and aspartate aminotransferase, alanine, glutamic acid, glycine, isoleucine, leucine, methionine, ornithine, proline, serine, threonine and valine were significantly increased in the exposed mice, while serum levels of cystine were decreased significantly. There were also non-significant increases in serum alkaline phosphatase, gama-glutamyl transpeptidase and some of the other amino acids. Chronic exposure to mixtures of organophosphorus pesticides is associated with decreased acetylcholinesterase activity, hepatic dysfunction and disturbance of amino acids profile. Biochemical indices of hepatocellular injury and disturbed amino acid metabolism may be of value as markers of chronic exposure to such pesticides.

The influence of personal protection, environmental hygiene and exposure to pesticides on the health of immigrant farm workers in a desert country

OBJECTIVES

Farm workers in developing countries tend not to use protective measures while handling pesticides. This study investigates the use of personal protection equipment and the practice of safety and hygiene procedures in the handling of pesticides in agriculture.

METHODS

Through a multi-stage sampling technique, one-fifth of the farms in a region were selected and all the farm workers at these farms were included in the study. A comparison population matching in age, socio-economic status and stay in the region was selected. A specifically designed questionnaire was used to collect information on the use of protective measures and the practice of safety and hygiene during work and on the disposal of empty pesticide containers. Blood pressure and erythrocyte acetylcholinesterase (AChE) activity were measured in the exposed and the unexposed populations.

RESULTS

Protective equipment was worn by a minority of farm workers - gloves, by 35%; work coveralls, by 36%; a scarf to cover the nose and mouth, by 39%; and shoes at work, by 79%. With regard to personal hygiene measures, 83% of the workers changed clothes after work and the same proportion took a shower after work; 63% and 46% drank and ate while at work respectively; and 11% used articles of domestic use in the preparation of pesticides on the farm. Most of the farm workers (96%) were asked to prepare pesticides for spraying by the foreman and 61% were asked to spray the pesticides on the crops. AChE activity was highly significantly depleted in the exposed population as compared with the unexposed population.

CONCLUSIONS

AChE depletion was found to be negatively associated with the use of gloves, of work coveralls, and of a scarf to cover the nose and mouth and with the implementation of safety and hygiene procedures on the farm. AChE depletion was positively associated with the frequency of pesticide spraying.

[American cutaneous leishmaniasis in a military training center located in Zona da Mata, Pernambuco, Brazil]

An outbreak of American cutaneous leishmaniasis has been occurred in military training unit localized in 'Zona da Mata' of Pernambuco State, Brazil, where were registered 26 human cases. An epidemiological survey was carried out by entomological investigation and Montenegro skin test (MST). Lutzomyia choti presents predominance (89.9%) in sandflies identified. Out of 545 men who realized training activities were 24.12% positive to MST.

Clinical evaluation and applications of the Amplicor HBV Monitor test, a quantitative HBV DNA PCR assay

Viral load has emerged recently as a reliable marker of disease progression and therapeutic efficacy in chronic infections, including AIDS and hepatitis C. The clinical management of type B hepatitis could also be improved by monitoring viremia levels in patients with chronic liver disease undergoing anti-viral treatment. To address this question we evaluated the performance of a newly developed, quantitative PCR assay (Amplicor HBV Monitor test, Roche Diagnostic Systems) in the assessment of viremia changes over time in a group of 45 patients with chronic active hepatitis (CAH) who received interferon treatment. Of the 45 patients, 14 were HBsAg and anti-HBeAg positive and 31 HBsAg, HBeAg positive. Follow-up extended up to 24 months. An average of ten samples per patient were analyzed for levels of ALT, IgM anti-HBc (Abbott Laboratories), HBV DNA by in-house dot-blot hybridization and hybridization-capture assays (HBV-DNA hybrid capture kit, Murex Diagnostics) and by Amplicor HBV Monitor. A sustained biochemical response was observed at the end of treatment in 12 HBeAg-positive and in seven anti-HBeAg positive patients. This was accompanied by the disappearance of HBeAg and of HBV DNA (hybridization assays) in all cases and by the clearance of IgM anti-HBc in 70% of the cases. Viremia (quantitative PCR assay) became undetectable only in 25-30% of cases and was associated with the loss of HBsAg. A good correlation was observed between the time course of IgM anti-HBc, quantitative PCR and dot-blot hybridization although the latter missed 33% of viremic samples. Together, these results indicate that the Amplicor HBV Monitor test is a robust and standardized assay for quantifying HBV viremia levels in the range from 10(2) to 10(7) copies/ml. Compared to other current markers, viral load may provide additional clinical information by predicting long term virologic response and HBsAg clearance in patients with normal ALT at the end of interferon therapy.

Morbidity among farm workers in a desert country in relation to long-term exposure to pesticides

OBJECTIVES

Farm workers chronically exposed to low levels of pesticides seldom show signs and symptoms of clinical significance. This study investigates subclinical morbidity patterns among male farm workers in a desert country.

METHODS

Migrant-established farm workers (N=226) were compared with referents (N=226) and with new farm workers (N=92) who had just entered the country to work on farms. Acetylcholinesterase activity was measured, the aiming test and digit symbol test were applied, and a morbidity profile was collected with a questionnaire.

RESULTS

The erythrocyte acetylcholinesterase activity and hemoglobin-adjusted erythrocyte acetylcholinesterase activity were significantly depleted in the established farm workers. The results of the aiming and digit symbol tests were also significantly lower for the established farm workers. For the morbidity profile, irritated conjunctiva (47.3%), watery eyes (52.2%), blurred vision (63.3%), dizziness (55.2%), headache (63.7%), muscular pain (61.1%), and weakness (76.6%) were reported by established farm workers in statistically significantly higher numbers than by the referents and new farm workers.

CONCLUSIONS

Morbidity patterns, such as the health complaints and objective parameters suggested in this study, would be suitable as criteria for identifying farm workers most at risk from pesticide toxicity and as criteria for initiating measures to control and reduce exposure.

Fed-batch bioproduction of spectinomycin

Actinomycetes produce about 67% of the known antibiotics covering a wide range of chemical structures. However, their filamentous growth present several problems during industrial processes. Among these problems oxygen transfer limitation is critical. In this chapter we present the role of oxygen in spectinomycin production by a Streptomyces species. Spectinomycin, a broad spectrum antibiotic effective against penicillin resistant gonorrhea, is an aminoglycoside constituted from two glucose moieties. Its bioproduction is strongly influenced by glucose and oxygen. We have shown that for a fixed dissolved oxygen concentration, there are two specific glucose concentrations which give maximum final titers of spectinomycin. The bi-modal maximum indicates the influence of two intermediate metabolites in spectinomycin biosynthesis. We propose a mechanism for spectinomycin biosynthesis and subsequently develop a model based on this mechanism. The proposed mechanism for spectinomycin biosynthesis is validated by successfully reconstructing the air flow rate profiles. A nonlinear systems theory technique termed External Differential Representation, is implemented to reconstruct the spectinomycin bioconversion process which then predicts the spectinomycin concentration from the air flow rate profile. This signifies that spectinomycin titers in industrial fed-batch processes can be controlled if a priori information about the air flow rate profile yielding maximum spectinomycin is available.

Abnormal endothelium-dependent responses in early radiation nephropathy

While arterial hypertension and renal dysfunction are well recognized complications of renal irradiation, the mechanisms that trigger the development of these complications are unknown. Recently, it was reported that the endothelium is a major target in radiation injury. Because dysfunction of the endothelial cells may lead or contribute to the development of hypertension and renal dysfunction in radiation nephropathy, we tested the hypothesis that endothelium-dependent vasodilation is impaired in radiated kidneys prior to the onset of hypertension. To test this hypothesis, we used Long-Evans rats that had undergone left nephrectomy (3 weeks earlier) and irradiation (3000 r's) to the right kidney 8 days earlier (mean blood pressures in the irradiated rats were not different than in the controls). We then measured the changes in renal blood flow (RBF) induced by endothelium-dependent (acetylcholine and bradykinin) and -independent (nitroprusside, norepinephrine, and angiotensin II) vasoactive agents. We found that the increases in RBF induced by the endothelium-dependent but not independent vasodilators were markedly impaired in the irradiated kidneys. Blocking nitric oxide synthesis with nitro L-arginine methyl ester in sham rats mimicked the blunted responsiveness of the irradiated rats, whereas indomethacin (an inhibitor of prostaglandin synthesis) had no effect on either sham or irradiated rats. Finally, the RBF responses to the endothelium-independent vasoconstrictors, norepinephrine and angiotensin II, were not altered in the irradiated kidneys. These results suggest that renal irradiation causes endothelial dysfunction (prior to the onset of hypertension) but spares the vascular smooth muscle cells.

Erythrocyte cholinesterase activity levels in desert farm workers

In this study we have examined 532 migrant farm workers engaged mainly in the cultivation of vegetable crops, in both greenhouses and openfarms, and an equal number of controls. Erythrocyte acetylcholinesterase activity (AChE) was measured to determine the degree of toxicity due to exposure to organophosphate and carbamate pesticides in the farm workers employed either as foremen (41.5%) or farmers (58.5%). The mean ages of the farm workers and controls were 35.2 +/- 7.4 (mean +/- SD) years and 34.6 +/- 7.1 years. AChE activity of the farm workers and controls was 3.89 +/- 0.64 UI/ml (mean +/- SD) and 4.15 +/- 0.29 UI/ml. The haemoglobin adjusted erythrocyte cholinesterase activity (HAChE) was 29.96 +/- 4.14 (mean +/- SD) for farm workers and 32.10 +/- 2.26 for controls. AChE activity was very highly significantly lower for the foremen (3.76 +/- 0.69) compared to farmers (3.98 +/- 0.59) (Student's t-test = 4.13, p = 0.0001). HAChE was also very highly significantly lower for foremen (29.24 +/- 4.37) compared to farmers (30.46 +/- 3.88) (Student's t-test = 3.64, p = 0.0001). The poorly controlled used of pesticides in the farms appeared to have caused sub-clinical intoxication in the farm workers and indicated the need for training and implementation of hygiene practices.

Noise-induced hearing loss, nationality, and blood pressure

Noise exposure has been associated with increased catecholamine production and blood pressure elevation in laboratory studies and in human volunteers. Epidemiologic studies have given conflicting results. In order to determine whether noise-induced hearing loss predicts a rise in blood pressure, we reviewed occupational medicine records in an occupational health center serving three companies where noise exposure is commonly found. Height, weight, blood pressure, and screening audiometry are obtained as part of routine occupational health screening, and the results of the screening visit are abstracted from written clinical records. The results of pure tone screening audiometry are reported in nonstandardized fashion (Normal, WNL, NAD, for example, for normal). We reviewed records from 1990 and 1991 inclusive. One investigator, blind to blood pressure status, assigned each record to "no hearing loss," "not codable," or "hearing loss assumed to be due to noise" on the basis of the written audiometry report. Hearing loss due to causes other than noise was considered not codable. No attempt was made to quantify severity of hearing loss. Two hundred and sixteen charts were excluded as "not codable," 1,535 were classified as having no hearing loss, and 610 had some degree of hearing loss, most probably due to noise exposure. To adjust for confounding covariates, multiple regression analysis was used and indicated that hearing status improves the regression model for predicting diastolic blood pressure (p = 0.04), following age, nationality, body mass index (BMI), and month of testing, although the effect is small. Stratification by age and BMI revealed increased diastolic pressure in the group with hearing loss under age 45, regardless of obesity.(ABSTRACT TRUNCATED AT 250 WORDS)

[Measles vaccination and age]

Recent studies have found administration of high-titre measles vaccine before 9 months of age to be associated with reduced survival. Since this suggests that early immunization could be unsafe, we examined the results of immunization campaigns with Schwarz standard measles vaccine carried out in 1980-1983 in three areas of Guinea-Bissau. Children were followed to death, migration or the age of five years. Children immunized at 4-8 months of age, of whom many were later re-immunized, had lower mortality between nine months and five years of age compared with children vaccinated at 9-11 months of age. The improved survival was unrelated to better protection against measles. There was no sign of socio-cultural differences between children immunized at different ages. Vaccination before 9 months of age is apparently safe and it may reduce childhood mortality compared with the currently recommended strategy of immunizing from nine months of age. Randomized trials are needed to confirm these observations which may have implications for the measles immunization strategy for developing countries.

Smoking among health professionals

A cross-sectional prospective study was conducted between the period December 1991 and November 1992, to identify the extent of smoking among practising doctors and other health professionals in general hospitals and health clinics in Al-Ain, United Arab Emirates. The study population consisted of 300 health professionals (doctors, specialists both clinical and non-clinical, pharmacists and dentists). They were handed self-administered questionnaires adapted from the World Health Organization standard questionnaire on smoking among health professionals. Among the responding 268 (89%) health professionals 197 (73.5%) were men, and 71 (26.5%) women. Among the men health professionals 86 (43.7%) were current smokers, 24 (12.2%) were ex-smokers and 87 (44.2%) were non-smokers, while among the women health professionals 4 (5.6%) were smokers, 1 (1.4%) was an ex-smoker and 66 (93%) were non-smokers. Doctors were uniformly aware of the detrimental effects of smoking, particularly its association with lung cancer, coronary artery disease, chronic bronchitis, and laryngeal cancer, and this was the major reason for their abstaining or wanting to quit the habit. The relationship of smoking with bladder cancer, soft tissue lesion (mouth and lip) and neonatal death was not well appreciated. Counselling patients about the hazards of smoking was practised significantly less often by doctors who smoked. The majority (83.6%) expressed the need for specific training for counselling patients to stop smoking. The options favoured by the health professionals for preventing smoking included a ban on tobacco advertising, specific health warnings on cigarette packets and restriction on smoking in public places, particularly in hospitals and clinics.

Smoking habits among physicians in two Gulf countries

The smoking habit of physicians in United Arab Emirates (UAE) and Kuwait were studied as first step towards surveying the habit among medical professionals. A cross-sectional survey was conducted in Kuwait between January-June 1990. Out of the 300 physicians who were contacted 252 (84%) completed the questionnaires, 190 (75%) were males and 62 (25%) were females. Among male physicians, current smokers were 86 (45.3%), ex-smokers were 34 (17.9%) and non-smokers were 70 (36.8%), while among the female physicians 10 (16%) were smokers and 52 (84%) were non-smokers. Also, a cross-sectional study was conducted between December 1991-November 1992 to identify the extent of smoking among physicians in UAE. Of the 300 physicians, 275 (91.6%) responded, 214 (77.8%) were males and 61 (22.2%) were females. Among the males, current smokers were 94 (43.9%), ex-smokers were 32 (14.9%) and non-smokers were 88 (41.2%), while among the females 5 (8.2%) were smokers, 3 (4.9%) were ex-smokers and 53 (86.9%) were non-smokers. Most important factors responsible for non-smoking doctors for not taking up smoking were: 'Protection of health', 'Self-discipline' and 'To set a good example to others'. The majority of physicians in UAE (91.3%) and Kuwait (75.6%) strongly agreed that smoking is hazardous to health. The results revealed that less than 50% of physicians provide information to over 70% of smoking patients. The majority of physicians and health professionals were aware of association between smoking and various diseases.(ABSTRACT TRUNCATED AT 250 WORDS)

Reduced childhood mortality after standard measles vaccination at 4-8 months compared with 9-11 months of age

OBJECTIVE

To evaluate the impact on mortality of standard Schwarz measles immunisation before 9 months of age.

DESIGN

Children vaccinated in 1980-3 at 4-5, 6-8, and 9-11 months of age were followed to migration, death, or the age of 5 years.

SETTING

One urban district and nine villages in two rural areas of Guinea-Bissau.

SUBJECT

307 children vaccinated at 4-8 months and 256 at 9-11 months.

MAIN OUTCOME MEASURES

Mortality from 9 months to 5 years of age for children immunised at 4-5, 6-8, and 9-11 months.

RESULTS

Mortality was significantly lower in children vaccinated at 6-8 months than at 9-11 months (mortality ratio = 0.63, (95% confidence interval 0.41 to 0.97), p = 0.047). As vaccination was provided in semiannual or annual campaigns it is unlikely that age at vaccination reflected a selection bias. The trend was the same in all three study areas. Improved survival after early immunisation was not related to better protection against measles infection. With a Cox multivariate regression model to adjust for age, sex, season at risk, season at birth, measles infection, and region, children vaccinated at 4-8 months had a mortality ratio of 0.61 (0.40 to 0.92, p = 0.020) compared with children vaccinated at 9-11 months. Reimmunised children tended to have lower mortality than children who received only one vaccine (0.59 (0.28 to 1.27, p = 0.176)).

CONCLUSION

Standard measles vaccination before 9 months is not associated with higher childhood mortality than is the currently recommended strategy of immunising from 9 months, and it may reduce mortality. This has implications for measles immunisation strategy in developing countries.

Bronchial asthma and wheeze in a desert country

A cross-sectional, population-based study was conducted among school children (3300), aged 7-12 years, in the Kingdom of Saudi Arabia, during the period January, 1988-February, 1990. The aim of the study was to investigate the association between asthma, allergic rhinitis, wheeze and eczema among Saudi school children. The relationship between pet-ownership and respiratory allergy was also studied. Detailed information was collected about wheeze and asthma in 3041 children and history of asthma and allergic rhinitis in their parents. The population sample had a high prevalence rate of diagnosed asthma (6.8%), history of wheeze (10.5%), allergic rhinitis (17.9%), and eczema (10.8%). Allergic rhinitis was the most frequently seen respiratory illness when compared to other respiratory symptoms. The prevalence rate of asthma, allergic rhinitis and eczema among parents reflected the same pattern as that seen in the children. Prevalence rate for asthma in children with pets is twice that of children without pets (OR: 2.4; 95%, Cl: 1.8-3.1). The odds of having chronic cough (OR: 3.9; 95% Cl: 2.8-5.2), chronic wheeze (OR: 4.2; 95%, 3.3-5.4), allergic rhinitis (OR: 8.0; 95% Cl: 6.3-10.3) and eczema (OR: 2.8: 95 Cl: 2.1-3.7) was higher in children with pets than in children without pets. The present study revealed that pet-ownership was associated with increased respiratory symptoms.

The effect of stress and fatigue on cardiac rhythm in medical interns

Twenty-four-hour ambulatory electrocardiographic monitoring was used to determine the incidence of arrhythmia while on-call and its relationship to stress and fatigue in 20 healthy medical interns. Mitral valve prolapse was present in 8 of 19 interns (42%). Heart rates ranged from a maximum of 103-167 beats/min (135 +/- 16) to a minimum of 38-61 beats/min (47 +/- 5). Interns had at least one episode of sinus tachycardia/h during 57% +/- 21% (range, 8-88%) of their hours on-call. Atrial premature beats (APB) were present in 19 of 20 (95%) and ventricular premature beats (VPB) in 12 of 20 (60%) subjects. APB/h ranged from 0 to 1.2 (0.4 +/- 0.3) and VPB/h from 0 to 23 (2 +/- 6). Three interns had multiform VPB and two had ventricular couplets. More APB/h occurred in interns under greater stress (0.5 +/- 0.4/h vs 0.3 +/- 0.1/h, p < 0.05) and combined stress and fatigue (0.6 +/- 0.4/h vs 0.2 +/- 0.2/h, p < 0.01). More VPB/h (5 +/- 9/h vs 0.5 +/- 0.6/h, p < 0.05) and higher (Lown) grade ventricular ectopy (2.3 +/- 1.6 vs 0.8 +/- 1.1; p < 0.05) occurred in interns under greater combined stress and fatigue. Mitral valve prolapse, sleep deprivation and caffeine intake were not associated with increased arrhythmia. The authors conclude that (1) rapid sinus tachycardia is frequent in interns while on-call and (2) interns experiencing greater stress and fatigue have more APB/h, VPB/h, and higher grade ventricular ectopy. These data support the notion that stress and fatigue may contribute to arrhythmia in healthy normal subjects.

Antibody responses after immunization with killed oral cholera vaccines during the 1985 vaccine field trial in Bangladesh

Sera collected during the 1985 oral cholera vaccine trial in Matlab, Bangladesh, which demonstrated efficacy of a whole cell combined with cholera B subunit vaccine (WC/BS) and a whole cell only vaccine (WC), were analyzed for antitoxin and vibriocidal antibodies. Before vaccines were given, antitoxin titers were highest in children, especially those with O blood group, whereas vibriocidal titers rose throughout life. Two weeks after three doses of vaccine, geometric mean antitoxin titers were 2.5-4.5 times higher in vaccinees who received the WC/BS vaccine; the vibriocidal titers were 1.3-2.1 times higher in vaccinees who received either vaccine. The titer elevations were relatively brief and were barely detectable 7 months after the third dose even though significant levels of protection persisted greater than or equal to 3 years. Thus, the oral vaccines induced a serum response in this large field trial that was similar to that seen in earlier pilot studies, but the duration of the serum responses was much shorter than the duration of the protection.