Effect of Deep Inspiration and Expiration on QTc Interval in Normal Healthy Subjects.

Background It is a well known fact that phases of respiration cause change in heart rate and autonomic tone of the heart. But how cardiovascular autonomic reflexes affect the electrocardiographic Heart rate-corrected QT interval (QTc) during the inspiratory and expiratory phase of respiration also need to be established. Objective To determine whether the respiratory phases influence the QTc interval or not. Method This was a quantitative, observational, cross-sectional study done at Kathmandu University School of Medical Sciences, Pre-Clinical Basic Science Block, Chaukot. Total one hundred students between 18 to 25 years of age, studying at KUSMS Pre-clinical science Block were included. QTc interval was recorded for normal respiration, deep inspiration and deep expiration by electrographic recording using ADInstruments. The values obtained were later analyzed using paired t-test in SPSS 16.0. Result The mean QTc interval during normal respiration was 392.1±21.6 milliseconds, during deep inspiration was 384.2±15.5 milliseconds and that following deep expiration was 395.0±13.1 milliseconds. There was no significant difference between QTc interval at the end of deep inspiration (p value < 0.05) and QTc interval at the end of deep inspiration (p value < 0.05) when compared with normal respiration. Conclusion This study shows that neither the inspiratory phase nor expiratory phase alters the QTc interval in normal healthy individual. Thus, it can also be implied that alteration in inspiratory and expiratory phase in various respiratory diseases does not cause any change in QTc interval.

Effect of Auditory Interference on Visual Simple Reaction Time.

Background Reaction time is the time between the application of the stimulus and the response. It is a physical skill based on human performance. Various factors like age, gender, distractions, personality, alcohol, etc. can affect the reaction time to a stimulus. Objective The objective was to determine whether auditory interference affects the visual simple reaction time or not. Method This is a quantitative, observational, cross-sectional study done at Kathmandu University School of Medical Sciences, Pre-Clinical Basic Science Block, Chaukot from April 2017 to June 2017. Total 120 participants who fulfilled the inclusion criteria and who were willing to participate in the study were included. Visual simple reaction time task was estimated alone without any interference followed by auditory interference using a software Deary Liewald reaction timer v3.10 in the laptop. The task was to press the spacebar as soon as the stimulus appeared in the screen of the laptop. Visual Reaction Time was recorded 20 times and the average of 20 recordings was given by the software itself which was later considered for statistical analysis. Then difference between the two values was reviewed using paired t-test since the data was normally distributed. Result The mean of visual simple reaction time for our study population was 298.93±37.12 milliseconds and the visual simple reaction time after auditory interference was 299.77±40.15 milliseconds. The difference between visual simple reaction time alone and after auditory interference was not significant (p=0.993). Conclusion This study shows that auditory interference doesn't affect the simple visual reaction time; so the person can perform daily activities even if there is some kind of auditory interference at the same time.

Effect of smoking cessation counseling within a randomised study on early detection of lung cancer in Germany.

INTRODUCTION: In the German lung cancer screening trial LUSI, smoking cessation counseling (SCC) was offered to all participants at time of randomization, and smoking habits were asked for within annual questionnaire inquiries. We analyzed the smoking habits of the participants within the first 2 years of follow-up and especially the potential effect of the SCC on these habits. MATERIALS AND METHODS: We used the smoking data of the initial inquiry on which the decision on invitation to the study was based, the socio-economic data of the questionnaire filled-in at time of randomization, the psycho-social data obtained during the SCC, and the annual questionnaire data of the first two annual follow-up screening rounds. RESULTS: Smoking prevalence decreased in the entire cohort significantly by 4 %, whereby the decrease was with 4.5 % statistically not significantly higher in the control arm than in the screening arm with 3.4 %. The decline was much stronger in the subgroup of attendees to stop-smoking counseling and mounted up therein to 10 %. In some participants, an increase of readiness to quit smoking was observed during the counseling hour, but did not show effects on smoking status 2 years later. DISCUSSION: We did not see a tendency to increased smoking among participants of the intervention arm or the entire study. The decline of smoking prevalence among the attendees of the counseling might be due to self-selection. Since the issue of effectiveness of smoking cessation counseling is important, further research with randomization into offering counseling or no intervention should be taken into consideration.

Increasing incidence of midterm and long-term complications after endovascular graft repair of abdominal aortic aneurysms: a note of caution based on a 9-year experience.

OBJECTIVE: To analyze the late complications after endovascular graft repair of elective abdominal aortic aneurysms (AAAs) at the authors' institution since November 1992. SUMMARY BACKGROUND DATA: Recently, the use of endovascular grafts for the treatment of AAAs has increased dramatically. However, there is little midterm or long-term proof of their efficacy. METHODS: During the past 9 years, 239 endovascular graft repairs were performed for nonruptured AAAs, many (86%) in high-risk patients or in those with complex anatomy. The grafts used were Montefiore (n = 97), Ancure/EVT (n = 14), Vanguard (n = 16), Talent (n = 47), Excluder (n = 20), AneuRx (n = 29), and Zenith (n = 16). All but the AneuRx and Ancure repairs were performed as part of a U.S. phase 1 or phase 2 clinical trial under a Food and Drug Administration investigational device exemption. Procedural outcomes and follow-up results were prospectively recorded. RESULTS: The major complication and death rates within 30 days of endovascular graft repair were 17.6% and 8.5%, respectively. The technical success rate with complete AAA exclusion was 88.7%. During follow-up to 75 months (mean +/- standard deviation, 15.7 +/- 6.3 months), 53 patients (22%) died of unrelated causes. Two AAAs treated with endovascular grafts ruptured and were surgically repaired, with one death. Other late complications included type 1 endoleak (n = 7), aortoduodenal fistula (n = 2), graft thrombosis/stenosis (n = 7), limb separation or fabric tear with a subsequent type 3 endoleak (n = 1), and a persistent type 2 endoleak (n = 13). Secondary intervention or surgery was required in 23 patients (10%). These included deployment of a second graft (n = 4), open AAA repair (n = 5), coil embolization (n = 6), extraanatomic bypass (n = 4), and stent placement (n = 3). CONCLUSION: With longer follow-up, complications occurred with increasing frequency. Although most could be managed with some form of endovascular reintervention, some complications resulted in a high death rate. Although endovascular graft repair is less invasive and sometimes effective in the long term, it is often not a definitive procedure. These findings mandate long-term surveillance and prospective studies to prove the effectiveness of endovascular graft repair.

Hypogastric artery aneurysm rupture after endovascular graft exclusion with shrinkage of the aneurysm: significance of endotension from a "virtual," or thrombosed type II endoleak.

Type II endoleaks, resulting from retrograde branch flow, after endovascular graft aneurysm exclusion are considered benign because they usually thrombose and are commonly associated with stable or shrinking aneurysm sacs. We report a hypogastric artery aneurysm rupture from endotension from an undetected, thrombosed Type II endoleak, associated with sac shrinkage. The patient had undergone an endovascular graft repair of a 4-cm right common iliac artery and 9-cm hypogastric artery aneurysm with distal hypogastric artery coil embolization. Serial computed tomography scans revealed no endoleak and a hypogastric aneurysm thrombosis with shrinkage. Eighteen months later, the aneurysm ruptured as a result of pressurization from backbleeding, patent branches.

Efficacy of a proximal occlusion catheter with reversal of flow in the prevention of embolic events during carotid artery stenting: an experimental analysis.

OBJECTIVE: The role of percutaneous angioplasty and stenting of carotid bifurcation lesions has been limited by its potential for producing embolic debris. We evaluated the efficacy of a proximal occlusion catheter (POC) in the prevention of embolic events during carotid artery stenting. In addition, pressure measurements relevant to the clinical application of this device were obtained from 10 patients undergoing carotid endarterectomy. METHODS: The POC is a guiding catheter with an occlusion balloon attached on the outside of the catheter at its distal end. Occlusion of the common carotid artery (CCA) was achieved by inflating the balloon while access to carotid bifurcation lesions was obtained through the inner lumen. The POC was inserted in the CCA of 10 dogs via the femoral artery. The side port of the POC was connected to a sheath placed in the femoral vein, thereby creating an external arteriovenous shunt. Ten artificial radiopaque particles simulating embolic particles and contrast agent were introduced in the CCA and monitored fluoroscopically. As a control, the same procedure was performed with a standard guiding catheter without an occlusion balloon. In 10 patients undergoing carotid endarterectomy, the internal carotid artery (ICA) and external carotid artery stump pressures and the pressure in the internal jugular vein were measured. RESULTS: Without the external arteriovenous shunt, in all animals there was prograde flow in the distal CCA despite CCA occlusion. This flow was derived from the thyroid artery. However, once the arteriovenous shunt was activated, reversal of flow in the distal CCA was achieved in each animal, and all the artificial particles were recovered from the side port of the POC. In the control group, each particle embolized to the brain (100%, P <.01). In the patients, the mean stump pressures in the ICA and external carotid artery and the jugular vein pressure were 51.8 +/- 14.2, 62.2 +/- 15.1, and 6.5 +/- 3.5 mm Hg, respectively. In each case, the jugular vein pressure was the lowest among the three. CONCLUSIONS: Obtaining proximal CCA control by inflating the POC does not sufficiently prevent embolization. However, reversal of flow in the ICA can always be created with the external shunt, which effectively prevents embolization. Thus, POC may markedly lower procedural stroke rates during carotid artery stenting. The ability of POC to prevent embolization before crossing the lesion with a guidewire may be an important advantage over other distal protection devices.

Identification of myosin light chains in Rana pipiens skeletal muscle and their expression patterns along single fibres.

Isoforms of myosin heavy chain (MHC) and myosin light chain (MLC) influence contractile kinetics of skeletal muscle. We previously showed that the four major skeletal muscle fibre types in Rana pipiens (type 1, type 2, type 3 and tonic; amphibian nomenclature) contain four unique MHC isoforms. In the present study we defined the MLCs expressed in each of these R. pipiens fibre types. The MLC composition of single MHC-typed fibres was determined from western blots using a panel of monoclonal MLC antibodies. A total of seven MLCs were identified, including four types of MLC1, two of MLC2 and a single MLC3. Twitch fibre types (types 1, 2 and 3) expressed MLC1(f) and MLC2(f), while tonic fibres contained a unique set of isoforms, MLC1(Ta), MLC1(Tb) and MLC2(T). MLC3 was expressed primarily in type 1, type 1-2 and type 2 fibres. Surprisingly, some frogs displayed a striking pattern of MLC expression where a unique isoform of MLC1 (MLC1(x)) was coexpressed along with the normal MLC1 isoform(s) in all fibre types. MLC1(x) was either expressed in all fibres of a given frog or was completely absent. The intraspecific polymorphism in MLC1 expression is likely to have a genetic basis, but is unlikely to be caused by allelic variation. The ratio of MLC3/MLC1 increased in direct proportion to the percentage of type 1 MHC, but was only weakly correlated. The variability in MLC3/MLC1 within a fibre type was extremely large. Both the MHC isoform and MLC3/MLC1 ratio varied significantly between 1 mm segments along the length of fibres. For all segments combined, MLC3/MLC1 increased with the percentage of type 1 MHC, but the correlation between segments was weaker than between fibres.

[Intestinal parasitic diseases in an urban environment in Sahel. A study in a district of Niamey, Niger]. / Les parasitoses intestinales dans l'environnement urbain au Sahel. Etude dans un quartier de Niamey, Niger.

Health and environment in Niamey, a capital in Sahel, are particularly linked owing to population growth, promiscuity and large pollution induced by human and animal excreta. One district, located in the centre of the town, was surveyed for drinking water quality (ammoniac and bacterial count) and use, as well as for the prevalence of parasites through both a random sample (fixed tools with methiolate-iodine-formaldehyde) and a systematic one (scotch-test). Water consumption was 16.5 litres/day/man from fresh water supplies (87%) and private wells (13%). Ammoniac measures were low in the wells but high in running water (pool and river). It was the same for faecal coliform bacteria. These results give evidence of biotope faecal pollution. The random sample (322 persons, male/female sex ratio 0,85, average age 20,6 years) showed a 42.1% parasitic prevalence. Amoeba was the most frequent parasite (53.6%); and Giardia (14.9%) was the most frequent pathogenic parasite. In the second sample (161 children under 10 years), 24.2% were carriers of oxyuris. This large intestinal parasitism, without any change in connection with previous data in Niger, points to an important fecal contamination of the people more by the way of "dirty hands" than consumption of drinking water. The parasites observed have a short biological cycle, not necessitating long-term maturation in the environment. Those whose ova or larvae must complete their cycle outside have no possibility of surviving in Sahel, thanks to the beneficial effect of sunlight (heat and ultraviolet light). The inhabitants of this district seem to have adapted to intestinal parasitism. But the occurrence of malnutrition linked to a new drought could lead rapidly to a very serious adverse result.

Arteriovenous malformation of the base of tongue: case report and literature review.

Arteriovenous malformations of the head and neck pose a challenging therapeutic and reconstructive problem. In this report we describe a rare case of an arteriovenous malformation of the base of tongue. The patient, a young adult female, was treated with embolization followed by surgical resection using a lateral pharyngotomy approach. Reconstruction of the extensive base of tongue defect was accomplished using a radial forearm free flap. Currently, the patient is decannulated, articulates clearly, tolerates a normal diet, and is without recurrence. Our treatment approach is discussed in detail and compared with alternative techniques.

[Symptoms of disease and food allergy in children with Down syndrome]. / Gezondheidsklachten en voedselallergie bij kinderen met het syndroom van Down.

OBJECTIVE: To obtain an impression of how often parents of children with Down's syndrome suspect their children of having a food allergy and what action results from this suspicion. DESIGN: Inventorizing controlled descriptive study. 'Zuid-Holland' in the Netherlands. METHODS: An anonymous questionnaire was sent to 110 parents of children with Down's syndrome and 223 control parents. RESULTS: The parents of children with Down's syndrome reported symptoms of their child which might relate to food allergy more frequently than control parents. They reported more respiratory disease symptoms (62% and 53% respectively; pneumonia: 22% and 3%), more gastrointestinal disease symptoms (28% and 17%; constipation or diarrhoea: 28% and 13%), but fewer skin disease symptoms (12% and 26%). 34% of the parents of Down's syndrome children and 22% of the control parents suspected their child of having an allergy and 13% in both groups suspected food to be the allergenic responsible. Medical and laboratory investigations were performed in 37% and 31% and food allergy was diagnosed in 7% and 31% respectively. No elimination-reïntroduction diet was reported as used for diagnosing. Parents of children with Down's syndrome were less satisfied with their consultation of health workers. All parents in both groups who suspected their children of having a food allergy started an elimination diet, 66% found it had a beneficial effect. CONCLUSION: Compared with control parents, parents of children with Down's syndrome reported symptoms relating to food allergy more frequently, suspected their children of having a food allergy equally often, but had it diagnosed less frequently. However, neither group of parents mentioned that an elimination-provocation test was used for the diagnosis.

Dermal absorption of polycyclic aromatic hydrocarbons in the blood-perfused pig ear.

Urinary 1-OH-pyrene, a metabolite of pyrene, is a sensitive biological marker for dermal absorption of pyrene in man. In order to determine whether this metabolite is a reliable biomarker of cutaneous absorption of other polycyclic aromatic hydrocarbons (PAHs), the blood-perfused pig ear model was used to compare the dermal absorption flux of pyrene with nine other PAHs after coal tar application. Cumulative absorption of PAHs into the perfusion blood, 200 min after application of an overdose of coal tar, ranged between 830 pmol cm-2 for phenanthrene to less than 4 pmol cm-2 for benzo[b]fluoroanthene, benzo[k]fluoranthene, benzo[a]pyrene, dibenzo[ah]anthracene and indeno[123-cd]pyrene. The results of this study show that when pyrene is used as a marker compound for PAH absorption through pig skin, the cumulative absorption of PAHs with a lower molecular weight will be underestimated: fluorene, tenfold; phenanthrene, 12-fold; anthracene and fluoranthene, ca. twofold. The percutaneous absorption of PAHs with a higher molecular weight than pyrene will be overestimated: e.g. benzo[a]pyrene, sevenfold; indeno [123-cd]pyrene, ca. 100-fold. It is likely that this conclusion is also valid for dermal PAH absorption in man.

Reduction of urinary 1-hydroxypyrene excretion in coke-oven workers exposed to polycyclic aromatic hydrocarbons due to improved hygienic skin protective measures.

The effect of hygienic skin protective measures on the internal exposure to polycyclic aromatic hydrocarbons (PAHs) was studied in 13 coke-oven workers. The study took place over 2 consecutive weeks. In 1 week the subjects worked under the normal circumstances, in the other week extra hygienic skin protective measures were instituted: laundered working clothes and a new pair of gloves before each 8-h work shift, and the washing both of the hands and of the face before each break. Biological monitoring was undertaken to measure the effect of the extra hygienic measures on the urinary 1-hydroxypyrene excretion, which is a measure of the internal PAH exposure. The increase of the urinary 1-hydroxypyrene concentration over the 4-day workweek was on average 37% lower when extra hygienic measures were taken, being 1.3 instead of 2.3 mumole 1-hydroxypyrene per mole creatinine (P = 0.03, N = 13). This study demonstrates that simple hygienic skin protective measures result in a significant reduction of the internal PAH exposure.

Smoking and dietary intake of polycyclic aromatic hydrocarbons as sources of interindividual variability in the baseline excretion of 1-hydroxypyrene in urine.

Seventy-six male volunteers, who were not occupationally exposed to polycyclic aromatic hydrocarbons (PAHs), participated in a study on the effect of tobacco smoking, alcohol consumption, dietary PAH intake, age, and body fat content on the baseline excretion of 1-hydroxypyrene in urine. Major determinants of urinary 1-hydroxypyrene excretion were smoking, dietary PAH intake, and age. The mean 1-hydroxypyrene concentrations in the urine of the volunteers in this study ranged between 0.05 and 0.79 mumol/mol creatinine. Smokers excreted on average 0.25 mumol/mol creatinine (range: 0.10-0.79 mumol/mol creatinine), and nonsmokers on average 0.12 mumol/mol creatinine (range: 0.04-0.29 mumol/mol creatinine). The average number of cigarettes smoked per day correlated well with urinary 1-hydroxypyrene concentrations (rs = 0.67, P < 0.001). The consumption of PAH-containing food products and active smoking account for 99% of total pyrene intake. The effect of age on 1-hydroxypyrene excretion is probably caused by a lower creatinine excretion in the elderly. Passive smoking and fat content had a statistically significant, but negligible effect on urinary 1-hydroxypyrene excretion. Passive smoking and the inhalation of ambient air are relatively in important for total pyrene intake (both account for less than 1%). Neither the consumption of alcohol nor the inhalation of ambient air significantly affected urinary 1-hydroxypyrene excretion. It is concluded that when urinary 1-OH-pyrene excretion is used in the assessment of PAH exposure, one should particularly be aware of the interindividual variability of the baseline excretion of PAH metabolites due to tobacco smoking and dietary PAH intake.

Estimation of individual dermal and respiratory uptake of polycyclic aromatic hydrocarbons in 12 coke oven workers.

Twelve workers from a coke plant in The Netherlands participated in an intensive skin monitoring programme combined with personal air sampling and biological monitoring during five consecutive eight hour workshifts. The purpose of the study was to make a quantitative assessment of both the dermal and respiratory intake of polycyclic aromatic hydrocarbons (PAHs). Pyrene was used as a marker compound for both dermal and respiratory exposure to PAHs. The biological measure for the internal exposure to PAHs was urinary 1-OH-pyrene concentration. Measurements on exposure pads at six skin sites showed that mean total skin contamination of the 12 workers ranged between 21 and 166 micrograms pyrene a day. The dermal uptake of pyrene ranged between 4 and 34 micrograms/day, which was about 20% of the pyrene contamination on skin. The mean concentration of total pyrene in the breathing zone air of the 12 coke oven workers ranged from 0.1 to 5.4 micrograms/m3. The mean respiratory uptake of pyrene varied between 0.5 and 32.2 micrograms/day. Based on the estimates of the dermal and respiratory pyrene uptake it is concluded that an average 75% (range 28%-95%, n = 12) of the total absorbed amount of pyrene enters the body through the skin. Because of the difference in the pyrene:benzo(a)pyrene ratio between the air samples and the skin contamination samples, the dermal uptake of benzo(a)pyrene was also estimated. This was about 51% of the total absorbed amount (range 8%-92%, n = 12). The total excreted amount of urinary 1-OH-pyrene as a result of exposure to PAHs during the five consecutive workshifts varied between 36 and 239 nmol. A multiple regression model of the mass balance between pyrene dose (both dermal and respiratory) and 1-OH-pyrene excretion confirmed the relevance of the dermal exposure route. The variation in urinary 1-OH-pyrene excretion was determined more by the dermal pyrene dose than by the respiratory dose. The model showed an estimate of the percentage of the absorbed amount of pyrene that is metabolised and excreted as 1-OH-pyrene in urine. For the 12 workers this percentage varied between 13% and 49% depending on smoking habits and consumption of alcohol. The results of this study indicate that among coke oven workers, the skin is the main route of uptake of PAHs. Preventive measures to reduce exposure to PAHs should be focused more on the reduction of dermal contamination by PAHs than on the reduction of inhaled dose.

Effect of the reduction of skin contamination on the internal dose of creosote workers exposed to polycyclic aromatic hydrocarbons.

Ten creosote-exposed workers of a wood impregnation plant participated in this study, which took place in two consecutive weeks on a Monday, after a weekend off. On one of the two days each worker wore Tyvek coveralls underneath his normal workclothes. Dermal contamination measurements (pyrene on exposure pads) and biological monitoring (urinary 1-OH-pyrene) were performed to measure the reduction of both the skin contamination and the internal dose. The total pyrene skin contamination of workers not wearing coveralls ranged between 47 and 1510 micrograms.d-1 (0.2-7.5 mumol.d-1). On the average, the coveralls reduced the pyrene contamination on the workers' skin by about 35 (SD 63)%. The excreted amount of 1-OH-pyrene in urine decreased significantly from 6.6 to 3.2 micrograms (30.2 to 14.7 nmol). Multiple regression analysis showed that skin contamination by polycyclic aromatic hydrocarbons is the main determinant of the internal exposure dose of creosote workers.

Absorption of polycyclic aromatic hydrocarbons through human skin: differences between anatomical sites and individuals.

In order to determine differences in absorption of polycyclic aromatic hydrocarbons (PAH) between anatomical sites and individuals, coal-tar ointment was applied to skin of volunteers at various sites. The surface disappearance of PAH and the excretion of urinary 1-OH-pyrene after skin application of coal-tar ointment were used as parameters for dermal PAH absorption. The surface disappearance was determined by the measurement of the fluorescence of PAH on skin. Surface disappearance measurements show low but significant differences in dermal PAH absorption between anatomical sites: shoulder > forehead, forearm, groin, > ankle, hand (palmar site). The average PAH absorption rate constant at different skin sites ranges from 0.036/h to 0.135/h (overall mean: 0.066/h). This indicates that after 6 h of exposure, 20-56% of a low dermal dose of PAH (e.g., about 1.0 ng pyrene/cm2) will be absorbed. The interindividual differences in PAH absorption are small (7%) in comparison with differences between anatomical sites (69%). Results based on the urinary excretion of 1-OH-pyrene are less clear. The site of application of the coal-tar ointment (dose: 2.5 mg/cm2 during 6 h) has no significant effect on the excreted amount of 1-OH-pyrene in urine. It is estimated that after coal-tar ointment application on skin, 0.3-1.4% of the pyrene dose (about 2 micrograms pyrene/cm2) becomes systemically available. For the accurate estimation of PAH uptake through skin of workers, it seems relevant to distinguish different body regions, not only because of the regional variation in percutaneous PAH absorption, but also because of the high dispersal of PAH contamination on skin of workers.

Dermal exposure to polycyclic aromatic hydrocarbons among primary aluminium workers.

Large amounts of PAH's are released in the electrode production departments of pre-bake cell aluminium reduction plants. Emission sources are mixing, shaping and baking of the anode (paste plant and bake oven) and pot relining operations. A study was performed to quantify the importance of dermal uptake of PAH's among exposed workers. Twenty workers in the anode production departments (paste plant (N = 8) and bake oven (N = 5)) and the pot relining department (N = 7) volunteered for the study. Monitoring was performed over a period of 5 consecutive days using personal air sampling, dermal contamination sampling and biological monitoring. Pyrene concentrations measured in the respirable air samples, ranged up to 320 micrograms/m3. Dermal contamination of pyrene was monitored at three skin sites (wrist, jaw/neck and groin) using exposure pads as pseudo-skin. The skin contamination with pyrene ranged up to 375 ng/cm2. Contamination of the groin skin site, although covered by work clothes ranged up to 106 ng/cm2. The concentration of 1-hydroxypyrene in pre and post-shift urine ranged up to 27 mumol/mol creatinine and showed an increase during the day and a decrease during the night. Pyrene in air and pyrene on the skin were tested for significance of correlation with urinary 1-hydroxypyrene in samples taken at several moments: end-of-shift, pre-shift next morning and weekly increase. The correlation coefficients between dermal contamination and urinary 1-hydroxypyrene were equal or higher than the correlation coefficient between pyrene air concentration and urinary 1-hydroxypyrene. The total skin contamination in exposed workers is estimated to be more than three times higher than the intake via the respiratory tract. The contribution of dermal exposure to the total PAH body burden of exposed workers therefore appears to be significant.

Prophylactic amnioinfusion during labor complicated by meconium: a preliminary report.

The purpose of this prospective and randomized study is to evaluate the safety and efficacy of prophylactic transcervical amnioinfusion in the management of labor complicated by meconium. A preexisting intrauterine pressure catheter was used for amnioinfusion. The incidence of thick meconium was significantly lower after amnioinfusion, compared with standard management (5% versus 62% p less than 0.0005). This was also demonstrated with spectrophotometry. Significant differences between the amnioinfusion group and the control group were found for the following: arterial cord pH less than 7.20 (16% versus 38%, p less than 0.05); meconium more than trace below the vocal cords at delivery (0% versus 29%, p less than 0.05) and need for positive pressure ventilation at birth (16% versus 48%, p less than 0.05). No complications related to amnioinfusion were observed. We conclude that (1) transcervical amnioinfusion during labor complicated by meconium is a simple and apparently safe procedure, and that (2) amnioinfusion effectively decreases the frequency of thick meconium, the frequency of neonatal acidemia, the frequency of more than trace meconium below the vocal cords, and the need for positive pressure ventilation.

Chitin structure and chitinase activity: isolation of structurally intact chitins.

Assessment of chitinase kinetics and mechanism in vitro has been hampered by lack of suitable substrates. We have previously reported rapid linear initial chitinase velocity with chitin substrate isolated from insect larval cuticle. Such chitin is shown to be fibrous in the light microscope. Methods are described for preparing fibrous chitins from any animal source including calcified carapaces. Evidence is given that chitin native fine structure in situ is maintained by structural proteins which in the fibrous chitin isolates are functionally replaced by covalently bound ester groups. Chitin fiber analogues thus reconstructed appear to have retained their native fine structure.