[Percutaneous transluminal coronary angioplasty in 1980-85 and 1995-96: more frequent multivessel disease, fewer reoperations and no change in mortality 1 and 5 years postoperatively]

OBJECTIVE

To describe the characteristics of patients undergoing coronary angioplasty (PTCA) over the past 20 years and the outcome after 1 and 5 years.

DESIGN

Prospective follow-up study.

METHODS

All patients who underwent a first PTCA in the Thorax centre of the Erasmus Medical Centre in Rotterdam during the period from 1 September 1980 through 30 November 1985 (group I) were compared with all patients who likewise underwent such a first PTCA during the period between 1 September 1995 and 31 December 1996 (group II). Data on the patients, the operations, any reoperations and the mortality were obtained from patient records, general practitioners and municipal archives. Cumulative percentages of survival and of not having rePTCA or coronary artery bypass surgery (CABG) were analysed by using the Kaplan-Meier-method.

RESULTS

Group I consisted of 856 patients and group II of 840 patients. The percentage of males decreased over the years from 80% to 69%. The average age increased from 56 to 60 years; the oldest patient in group I was 75 years and the oldest in group II was 87 years. The percentage of patients with multivessel disease increased from 36% to 44%. Stent implantation occurred in 55% of the patients in group II (0% in group I). The necessity for urgent CABG due to unsuccessful PTCA decreased from 9.4% to 1%. After 1 year, the percentage of coronary revascularisations was 28.8% in group I and 22.6% in group II (p = 0.01). The perioperative mortality and the 5-year survival were not significantly different in the two groups (group I: 1.3% and 90%; group II: 2.4% and 88%, respectively). For both groups, higher age, a smaller ejection fraction, more extensive vascular disease and no treatment with statins were independent predictors of a higher mortality after 5 years. In group II, renal function disorders were the most important predictor of higher mortality.

Non-invasive coronary angiography with multislice spiral computed tomography: impact of heart rate

OBJECTIVE

To evaluate the impact of heart rate on the diagnostic accuracy of coronary angiography by multislice spiral computed tomography (MSCT).

DESIGN

Prospective observational study.

PATIENTS

78 patients who underwent both conventional and MSCT coronary angiography for suspicion of de novo coronary artery disease (n=53) or recurrent coronary artery disease after percutaneous intervention (n=25).

SETTING

Tertiary referral centre.

METHODS

Intravenously contrast enhanced MSCT coronary angiography was done during a single breath hold, and ECG synchronised images were reconstructed retrospectively. All coronary segments of > or = 2.0 mm without stents were evaluated by two investigators and compared with quantitative coronary angiography. Patients were classified according to the average heart rate (mean (SD)) into three equally sized groups: group 1, 55.8 (4.1) beats/min; group 2, 66.6 (2.8) beats/min; group 3, 81.7 (8.8) beats/min.

RESULTS

Image quality was sufficient for analysis in 78% of the coronary segments in patients in group 1, 73% in group 2, and 54% in group 3 (p < 0.01). The sensitivity and specificity for detecting significant stenoses (> or = 50% lumen reduction) in these assessable segments were: 97% (95% confidence interval (CI) 84% to 100%) and 96% in group 1; 74% (52% to 89%) and 94% in group 2; and 67% (33% to 90%) and 94% in group 3 (p < 0.05). Accounting for all segments of > or = 2.0 mm, including lesions in non-assessable segments as false negatives, the sensitivity decreased to 82% (28/34 lesions, 95% CI 69% to 91%), 61% (14/23 lesions, 42% to 77%), and 32% (6/19 lesions, 15% to 50%), respectively (p < 0.01).

CONCLUSIONS

MSCT allows reliable coronary angiography in patients with low heart rates.

Routine intracoronary beta-irradiation. Acute and one year outcome in patients at high risk for recurrence of stenosis

AIMS

Intracoronary radiation is a promising therapy potentially reducing restenosis following catheter-based interventions. Currently, only limited data on this treatment are available. The feasibility and outcome in daily routine practice, however, is unknown.

METHODS AND RESULTS

In 100 consecutive patients, intracoronary beta-radiation was performed with a (90)Strontium system (Novoste Beta-Cathtrade mark) following angioplasty. Predominantly complex (73% type B2 and C) and long lesions (length 24.3+/-15.3 mm) were included (37% de novo, 19% restenotic and 44% in-stent restenotic lesions). Radiation success was 100%. Mean prescribed dose was 19.8+/-2.5 Gy. A pullback procedure was performed in 19% lesions. Geographic miss occurred in 8% lesions. Periprocedural thrombus formation occurred in four lesions, dissection in nine lesions. During hospital stay, no death, acute myocardial infarction, or repeat revascularization was observed. Major adverse cardiac events occurred predominantly between 6 and 12 months after the index procedure with major adverse cardiac event-free survival of 66% at 12 months (one death, 10 Q-wave myocardial infarctions, 23 target vessel revascularizations; ranked for worst event).

CONCLUSION

Routine catheter-based intracoronary beta-radiation therapy after angioplasty is safe and feasible with a high acute procedural success. The clinical 1-year follow-up showed delayed occurrence of major adverse cardiac events between 6 and 12 months after the index procedure.

The environmental pollutant hexachlorobenzene causes eosinophilic and granulomatous inflammation and in vitro airways hyperreactivity in the Brown Norway rat

Based on observations that the persistent environmental pollutant hexachlorobenzene (HCB) induces inflammatory skin lesions and eosinophilic and granulomatous lung pathology as well as in vivo airways hyperresponsiveness to methacholine in the BN/SsNOlaHsd rat (Michielsen et al., Toxicol Appl Pharmacol 172:11-20, 2001), which are features of human Churg-Strauss syndrome (CSS), we have investigated whether HCB induced other features of CSS such as asthma and systemic vasculitis involving the heart and kidneys in this strain of rat. To this end, BN/SsNOlaHsd rats received control feed or feed supplemented with 450 mg/kg HCB. On days 6, 14 or 21, tracheas were isolated to assess non-specific in vitro airways hyperresponsiveness (AHR) to cumulative concentrations of arecoline and serotonin. In addition, lungs were lavaged to count and differentiate lavage cells, and skin, lungs, heart, kidneys, and lymph nodes were processed for histopathological investigation. HCB induced eosinophilic and granulomatous lung pathology in the BN/SsNOlaHsd rat, which became more severe with time and was associated with significant in vitro AHR to arecoline. Moreover, as in CSS-patients, systemic effects on spleen and lymph nodes were observed in HCB-fed BN/SsNOlaHsd rats, as well as development of skin lesions with vascular changes and eosinophilic infiltrates. In contrast, cardiac or renal involvement, frequently seen in CSS-patients, was not seen in HCB-fed rats. More importantly, there were no indications of necrotizing vasculitis, a hallmark feature of CSS, in the lungs and skin of BN/SsNOlaHsd rats. Thus, it is concluded that the persistent environmental pollutant HCB possibly induces a mild or early stage of CSS in the BN/SsNOlaHsd rat that may evolve into fully developed CSS after prolonged exposure to HCB.

Coronary restenosis elimination with a sirolimus eluting stent: first European human experience with 6-month angiographic and intravascular ultrasonic follow-up

AIMS

Coronary stenting is limited by a 10%-60% restenosis rate due to neointimal hyperplasia. Sirolimus is a macrocyclic lactone agent that interacts with cell-cycle regulating proteins and inhibits cell division between phases G1 and S1. The hypothesis tested in this study is that local delivery of sirolimus with an eluting stent can prevent restenosis.

METHODS AND RESULTS

Fifteen patients were treated with 18 mm sirolimus eluting BX VELOCITY stents. Quantitative angiography and three-dimensional quantitative intravascular ultrasound were performed at implantation and at the 6 months follow-up. All stent implantations were successful. One patient died on day 2, of cerebral haemorrhage and one patient suffered a subacute stent occlusion due to edge dissection (re-PTCA, CKMB 42). At 9 months no further adverse events had occurred and all patients were angina free. Quantitative coronary angiography revealed no change in minimal lumen diameter and percent diameter stenosis and hence no in-lesion or in-stent restenosis. Quantitative intravascular ultrasound showed that intimal hyperplasia volume and percent obstruction volume at follow-up were negligible at 5.3 mm(3)and 1.8%, respectively. No edge effect was observed in the segments proximal and distal to the stents.

CONCLUSION

Implantation of a sirolimus-eluting stent seems to effectively prevent intimal hyperplasia.

[Twelve year triage and thrombolysis treatment prior to hospitalization for myocardial infarction patients in the Rotterdam area of the Netherlands: outstanding short-term and long-term results]

OBJECTIVE

To describe the results of thrombolysis prior to hospitalisation in patients with evolving myocardial infarction.

DESIGN

Prospective cohort study.

METHOD

The 'Reperfusion for acute infarcts Rotterdam' (Dutch acronym: REPAIR) programme aims to minimise treatment delay in patients with evolving myocardial infarction by the initiation of thrombolytic therapy prior to hospital admission. For patients with symptoms that indicate a developing myocardial infarction, treatment is initiated immediately by the ambulance personnel at the patient's home, once the diagnosis has been confirmed with the help of a portable 12-lead ECG system. The interval between the onset of symptoms and the thrombolysis infusion was recorded for all patients, as well as any complications which occurred during transportation. The long-term survival was determined using data from the municipal registration.

RESULTS

In the period 1988-2000, 1487 patients were treated using the REPAIR protocol, 80% of these within two hours after the onset of symptoms. In 9 cases (0.6%) a thrombolytic treatment had been initiated, whereas the diagnosis 'myocardial infarction' was not confirmed at the hospital. During transport 40 patients (2.7%) experienced ventricle fibrillation, 25 (1.7%) severe hypotension, and 2 patients (0.1%) died. Mortality at 30 days and at one, five, and ten years was 4.9%, 7.3%, 16.2% en 30.1%, respectively. Patients treated within two hours after the onset of symptoms had lower mortality rates than those treated later: at one year 6.7% versus 9.7%, and at 5 years 14.0% versus 25.1% (Kaplan-Meier estimates; log rank test: p = 0.001).

CONCLUSION

Immediate thrombolytic treatment of patients with a developing myocardial infarction which could be safely initiated by ambulance personnel, resulted in excellent short-term and long-term survival.

On the annoyance caused by impulse sounds produced by small, medium-large, and large firearms

A laboratory study was designed in which the annoyance was investigated for 14 different impulse sound types produced by various firearms ranging in caliber from 7.62 to 155 mm. Sixteen subjects rated the annoyance for the simulated conditions of (1) being outdoors, and (2) being indoors with the windows closed. In the latter case, a representative outdoor-to-indoor reduction in sound level was applied. It was anticipated that the presumed additional annoyance caused by the "heaviness" of the impulse sounds might be predicted from the difference between the C-weighted sound exposure level (CSEL; LCE) and the A-weighted sound exposure level (ASEL; LAE). In the outdoor rating conditions, the annoyance was almost entirely determined by ASEL. The explained variance, r2, in the mean ratings by ASEL was 0.95. In the indoor rating conditions, however, the explained variance in the annoyance ratings by (outdoor) ASEL was significantly increased from r2 = 0.87 to r2= 0.97 by adding the product (LCE-LAE)(LAE-alpha) as a second variable. In combination with a 12-dB adjustment for small firearms, the present results showed that for the entire set of impulse sounds rated indoors with windows closed, the rating sound level, Lr, is given by Lr=LAE +12dB+beta(LCE-LAE)(LAE-alpha), with alpha=45dB and beta=0.015dB(-1). For the outdoor rating condition, the optimal parameter values were equal to alpha=57 dB and, again, beta=0.015 dB(-1). In validation studies, in which the effects of the present rating procedure will be compared to field data, it has to be determined to what extent the constants alpha and beta have to be adjusted.

The mercapturic acid biotransformation pathway of hexachlorobenzene is not involved in the induction of splenomegaly, or skin and lung lesions in the Brown Norway rat

Involvement of the mercapturic acid pathway in the induction of splenomegaly and skin and lung pathology by hexachlorobenzene (HCB) in the rat was investigated by seeking to determine whether pentachloronitrobenzene (PCNB) has the same inflammatory effects as HCB, since both compounds are directly conjugated to glutathione, and further processed into the same mercapturic acid metabolites which are excreted via the urine. Female Brown Norway (BN/SsNO1aHsd) rats at 3 to 4 weeks of age were orally exposed to diets with or without supplementation with 450 mg HCB or equimolar (467 mg) or higher (934 mg) amounts of PCNB per kilogram of diet over 4 weeks. Gross skin lesion development and body weight gains were assessed during exposure and spleen and liver weights as well as histopathologic changes in skin and lung were assessed after exposure. After 3 weeks of exposure, urinary metabolites of the mercapturic acid and oxidative biotransformation pathways were identified using high-performance liquid chromatography (HPLC) and liquid chromatography-mass spectrometry (LC-MS). Oral exposure of the rats to 450 mg/kg HCB resulted in an increase in relative spleen and liver weights as well as in the development of skin and lung pathology in the absence of overall liver toxicity. Equimolar or higher concentrations of PCNB caused none of these effects. Urinary levels of the mercapturic acid N-acetyl-S-(pentachlorophenyl)-cysteine (PCP-NAC), were comparable in HCB- and PCNB-treated rats. Levels of closely related methylsulfide derivatives of PCP-NAC, also generated via the same mercapturic acid pathway, appeared to be significantly higher in PCNB- than in HCB-treated rats, whereas the reverse was true for the urinary levels of the oxidative metabolite pentachlorophenol (PCP). Thus, results indicate that metabolites of the mercapturic acid pathway are not involved in the induction of splenomegaly and skin and lung pathology caused by HCB exposure in BN rats and that the main urinary metabolite of HCB in these BN rats is PCP. Since PCP itself, as well as other cytochrome P450-derived metabolites from HCB, are not likely to be involved in the induction of splenomegaly and skin and lung pathology, it is suggested that either the parent compound HCB or as-yet-unidentified non-P450-generated metabolites are involved in these inflammatory effects of HCB.

A field survey on the annoyance caused by sounds from large firearms and road traffic

Subjective reactions to artillery sounds were determined for over 400 respondents divided among 17 different residential areas. Also, for the same respondents, the subjective effects of road-traffic sounds were determined enabling a comprehensive comparison of the dose-response relations. For the sake of comparison with other field surveys, the noise dose for the shooting sounds was, among other things, expressed as the yearly average C-weighted day-night level (CDNL) and that for the road-traffic sounds was expressed as the A-weighted day-night level (ADNL). Similarly, for both sound types the community response was expressed as the percentage of respondents being "highly annoyed." From the comparison of the two dose-response relationships it could be concluded that for numerically equal day-night levels, the artillery sounds were more annoying than the road-traffic sounds. Overall, the difference was equivalent to the change in annoyance produced by a 5-dB shift in the yearly average day-night levels of the sounds. With equal day-night levels for "downwind" conditions, the artillery and road-traffic sounds were equally annoying. Results from the present highly controlled field survey provided a new opportunity to optimize the parameter values in Schomer's rating procedure y = (1/beta)(LCE-PNSE) + PNSE, in which the noise exposure for impulsive sounds (y) is expressed as the A-weighted SEL of equally annoying vehicle sounds. PNSE represents the point at which the impulsive and vehicle sounds with numerically equal levels are also equally annoying. With PNSE fixed at 103 dB, an optimal solution was found with slope beta set to 1.3. With the previously recommended slope beta = 0.67, the rating sound level for artillery sounds would be underestimated by almost 12 dB.

Daily home haemodialysis in The Netherlands: effects on metabolic control, haemodynamics, and quality of life

BACKGROUND

More frequent dialysis has been claimed to improve clinical outcome and quality of life.

METHODS

Clinical status was optimized in 13 haemodialysis patients during a run-in period of 2 months with three dialysis sessions a week. Thereafter, daily home haemodialysis (DHHD, 6 sessions per week) was initiated. The total weekly dialysis dose (Kt/V) was kept constant.

RESULTS

Weekly Kt/V was 3.2+/-0.13 (M+/-SEM) before, and 3.2+/-0.15 after 6 months of DHHD (NS), time-averaged concentration of urea (TACu) was 21.2+/-1.6 mmol/l and 20.1+/-0.9 mmol/l (NS). Urea reduction was 0.56+/-0.05 before DHHD, and 0.41+/-0.06 during DHHD (P<0.0001). Serum K remained unchanged, but significantly less exchange resins were used (P<0.02). Also, the dose of phosphate-binding agents could be decreased. Values for Na, K, Cl, bicarbonate, Ca, PTH, albumin, and Hb remained unchanged. Iron deficiency developed in some patients. Twenty-four-hour blood pressure monitoring showed a decrease of systolic blood pressure (141.1+/-17.2 mmHg before, and 130.9+/-19.2 mmHg during DHHD, P<0.001). Diastolic blood pressure remained constant (82.8+/-7.2 and 76.9+/-10.1 mmHg, NS). Mean arterial pressure decreased from 102.2+/-9.5 to 94.9+/-1.4 mmHg (P<0.02). Blood pressure decreased mainly in previously hypertensive patients. Mean target weight increased 0.8 kg. The amount of antihypertensive drugs used decreased from 1.88+/-0.35 to 0.75+/-0.17 (P<0.005, n=7). Dialysis sessions were much more stable, also in patients with cardiac insufficiency. Quality of life questionnaires (Rand 36, Nottingham Health Profile, Uraemic Symptoms Profile) showed a significant improvement of physical condition and fewer uraemic symptoms.

CONCLUSION

DHHD compared to conventional thrice-weekly haemodialysis with similar weekly Kt/V results in an improved haemodynamic control and quality of life, but has lesser impact on metabolic regulation.

EUROPA substudies, confirmation of pathophysiological concepts. European trial on reduction of cardiac events with perindopril in stable coronary artery disease

In patients with coronary disease, ACE inhibitors may improve endothelial function in the coronary arteries as well as peripheral arteries, and may have anti-proliferative effects which might result in retardation of progression of coronary artery disease. In order to verify these pathophysiological concepts, a series of substudies will be conducted as part of the EUROPA programme. Angiographic and intravascular ultrasound examination of coronary arteries will be performed in approximately 400 patients before and after 3 years' treatment with either perindopril or placebo, in order to assess progression and possible regression of coronary lesions. B-mode ultrasonography of the brachial artery will be used as a model for changes in the coronary arteries, to assess endothelial function in response to ischaemia (reactive hyperaemia) and to vasoconstriction (cold pressor test). Three hundred patients will be investigated before and at different intervals after initiation of study treatment. In addition genetic characterization will be performed of patients participating in EUROPA in order to assess whether specific genotypes do respond more or less favourably to perindopril. In addition, the effect of perindopril will be investigated in patients with diabetes type II, since ACE inhibition in such patients may improve microvascular function and renal function. Integration of these substudies, as well as detailed analysis of other specific subgroups in EUROPA, will help us understand the effects of treatment with perindopril in patients with stable coronary artery disease.

Monk seal mortality: virus or toxin?

During the past few months, more than half of the total population of about 300 highly endangered Mediterranean monk seals (Monachus monachus) on the western Saharan coast of Africa, died in a mysterious disease outbreak. Epizootiological and postmortem findings were reminiscent of similar outbreaks amongst pinniped and cetacean species in recent years, which were caused by an infection with newly discovered morbilliviruses (for review see osterhaus et al.). Virological, as well as toxicological, analysis performed on tissue samples collected from relatively fresh carcasses during the outbreak indicate that infection with a virus closely related to dolphin morbillivirus (DMV), possibly originating from affected dolphins in the same area, was the primary cause of the outbreak. Therefore it is concluded that vaccination with a safe and effective non-replicating vaccine should be considered as a management tool in the conservation of Mediterranean monk seals.

Improved injection practices after the introduction of treatment and sterility guidelines in Tanzania

OBJECTIVE

To evaluate the effect of introduction of treatment and sterilization guidelines on the number of avoidable injections and on the sterility of needles and syringes.

METHODS

In 1991, 66 randomly selected health units in Mwanza Region, Tanzania, were visited and factors were determined that might contribute to HIV transmission by injections. In a workshop with all senior health workers from the region, findings were presented and treatment and sterilization guidelines developed. Thereafter, seminars were held at each health centre of the region. Four months after the intervention, data were collected at the same health facilities in order to assess changes in prescribing practices, sterilization procedures, and sterility of needles and syringes.

RESULTS

The knowledge on indications for injections improved markedly for paramedical staff. The proportion of outpatients receiving an injection dropped from 23% to 10% and the proportion of patients receiving an avoidable injection dropped from 16% to 6%. Procedures for sterilization, keeping sterilized equipment, and administration of injections improved. A smaller proportion of sterilized needles and syringes tended to be contaminated in dispensaries, but this reduction from 44% to 22% was not significant.

CONCLUSION

Considerable improvement in knowledge, prescription practices and sterility procedures was observed at dispensary level after carrying out a training programme.

Urine production rate and renal blood flow in the near-term ovine fetus are not related to high and low voltage electrocortical activity

Studies in both the human and ovine near-term fetus have identified the clustering of physiologic and behavioral parameters into states. In a recent study in the human fetus a considerable decrease was found in fetal urine production during non-rapid eye movement (non-REM) compared with REM sleep. Whether this decrease was caused by decreased renal blood flow or changes in urine concentration is not known. This prompted us to investigate the relation between fetal urine production rate and electrocortical activity in the near-term ovine fetus. We hypothesized that in the ovine fetus urine production and renal blood flow during REM [comparable to low voltage electrocortical activity (LV ECoG)] would be lower than during non-REM [(high voltage (HV) ECoG)]. In eight fetal sheep between 123 and 127 d of gestation (term 147 d), ECoG, renal blood flow, urine flow, and urine osmolality were measured continuously for 6 h on 2 consecutive days. Data were analyzed into HV ECoG and LV ECoG whereafter urine flow, urine osmolality, and renal blood flow data were averaged per state. We found no significant differences in urine flow, urine osmolality, or renal blood flow between the two behavioral states in the ovine fetus. Because these data are in sharp contrast to those found in the human fetus, we conclude that the observed dissimilarities in renal responses between the human and sheep fetus add to the already known differences in behavioral states between the two species.

Evolution of coronary atherosclerosis in patients with mild coronary artery disease studied by serial quantitative coronary angiography at 2 and 4 years follow-up. The Multicenter Anti-Atheroma Study (MAAS) Investigators

AIMS

Angiographic studies on the natural course of both focal and diffuse coronary atherosclerosis have not been performed before, but can both be assessed by quantitative coronary angiography. The objective of this study was to describe the natural course of focal and diffuse coronary atherosclerosis over time.

METHODS AND RESULTS

In 129 patients with mild coronary artery disease, but not on lipid-lowering medication, three coronary angiograms were made each 2 years apart. Nine hundred and sixty five angiographically diseased and non-diseased segments were analysed by quantitative coronary angiography. Mean lumen diameter and minimal lumen diameter were used as measures of diffuse and focal coronary atherosclerosis. Mean lumen diameter and minimum lumen diameter decreased by 0.02 and 0.03 mm per year. The rate of progression was similar in the angiographically non-diseased, as in the mildly and moderately diseased segments. Progression of diffuse coronary atherosclerosis was largest in severely stenosed lesions (percentage diameter stenosis > or = 50%) and in the right coronary artery with a loss of 0.19 mm and 0.16 mm in mean lumen diameter. Progression of focal disease was most prominent in new and mild lesions and the right coronary artery, with a decrease in minimum lumen diameter of 0.34 mm and 0.22 mm. In most subgroups, progression occurred gradually over time. On a per segment level, progression and the occurrence of new lesions occurred in 4.4% and 4.2%. Regression and disappearance of a lesions was found in 2.3% and 1.9%. On a per patient level, 36% were progressors, 12% had a mixed response, 36% were stable, and 16% were regressors.

CONCLUSION

Diffuse and focal coronary atherosclerosis progressed at the same rate in the first and second 2 years in stenosed and non-stenosed segments. The rate of coronary atherosclerosis progression was small, but was higher for focal than for diffuse disease. A minority of lesions progressed and spontaneous regression was rare.

Annoyance caused by sounds of wheeled and tracked vehicles

In a laboratory experiment, the relationship between the annoyance caused by sounds of tracked and wheeled vehicles was investigated. Sounds of various vehicles, ranging from a main battle tank (MBT) to a passenger car, were recorded at several distances. Subjects were presented with these sounds and were asked to judge the annoyance if they were exposed to them at home on a regular basis. Overall, sounds emanated from military tracked vehicles were judged to be less annoying than civil passenger cars, provided that the indoor A-weighted sound-exposure levels (ASELs) were the same. It should be noted that receiver distance and operating conditions were not specifically matched for military and civil vehicles but were chosen to represent typical ranges of values found in practice. For steady-speed conditions, the sounds were judged to be equally annoying if the (indoor) ASELs of the tracked armored personnel carrier (APC) and the MBT exceeded that of a passenger car by 5 and 10 dB, respectively. In specific driving conditions such as alternate accelerations and decelerations, however, these differences were smaller. For ASELs below 55 dB, passenger cars were found to be more annoying than heavier wheeled vehicles, such as a bus or a truck with a trailer. The data indicate that the difference between the high-frequency part and the low-frequency part of the spectrum might play a role in the annoyance. With respect to noise-zoning procedures it is highly interesting that the outdoor ASEL could predict the annoyance, as rated indoors, better than could any indoor noise measure. The 5- and 10-dB bonuses to the indoor level of the APC and the MBT, respectively, were reduced to 1 and 3 dB if the dose was measured outdoors.

Detection of wild-type Aujeszky's disease virus by polymerase chain reaction in sheep vaccinated with a modified live vaccine strain

An outbreak of Aujeszky's disease occurred in a flock of sheep which had been housed together with pigs. After the death of five sheep with clinical signs of Aujeszky's disease, the remaining sheep were vaccinated with the Bartha vaccine strain, and the pigs were vaccinated with the 783 vaccine strain of Aujeszky's disease virus. Despite vaccination, however, more sheep died. Brain tissues from four sheep were collected for virus isolation and for immunohistological examinations. Only vaccine virus (gE-negative) was detected in the tissue. After DNA restriction enzyme analysis of the isolated virus, DNA of one or both of the vaccine strains was detected in all sheep. In one sheep field virus DNA was also detected. However, when the polymerase chain reaction was performed on samples prepared from paraffin-embedded tissues, DNA of field virus (gE-positive) was detected in all four sheep. It was probable that the sheep had not yet mounted a sufficient immune response to the vaccine virus, or were already infected with field virus at the time of vaccination. We concluded that the sheep died from field virus infection and not from vaccine virus infection and that only the polymerase chain reaction made it possible to specifically detect even very small amounts of field virus DNA among vaccine virus DNA in all investigated sheep.

Risk factors for HCV infection in two haemodialysis units in The Netherlands

BACKGROUND

In order to assess risk factors for HCV infection during haemodialysis, all patients receiving haemodialysis for more than 6 months in two separate units in the Netherlands were studied retrospectively.

METHODS

Antibodies to HCV, HCV-RNA and HCV genotypes were determined. Risk factors were identified by analysis of an extensive collection of clinical data.

RESULTS

In unit A, 8 out of 75 (11%) patients and in unit B 4 out of 122 (3%) patients had antibodies to HCV. Eleven out of the 12 anti-HCV-positive patients had detectable HCV-RNA. Genotyping showed the presence of 4 different genotypes in unit A (1, 1a, 2b, and 3a). Three patients in unit B were infected with the same genotype (1b), where one of these patients was also infected with genotype 1a. One patient in unit B did not have detectable HCV-RNA. The risk of acquiring a HCV infection in unit A was associated with the number of blood transfusions. However, in unit B this risk was associated with the duration of dialysis. Other factors such as the number of surgical procedures were not associated with HCV infection.

CONCLUSIONS

Blood transfusions and the dialysis process itself are important and independent risk factors for HCV transmission in dialysis patients. Surgical events do not appear to be important risk factors. However, relative risks may vary considerably between different dialysis centres.

Injection practices in Mwanza Region, Tanzania: prescriptions, patient demand and sterility

This paper describes prescription and sterilization practices in Mwanza Region, Tanzania, before the introduction of interventions aiming at reducing HIV transmission by injections. Sixty-six health facilities from Mwanza Region were included in the study. Data were collected in interviews and questionnaires, through structured observation, bacteriological culture and record analysis. Criteria for avoidable injections were based on recommendations of the Essential Drugs Programme and on a regional consensus workshop. One in 4 out-patients received an injection 70% of which were avoidable. Most were given for acute respiratory infections, skin diseases and urinary tract infections. Forty per cent of cultures taken from sterilized needles and syringes yielded growth of microorganisms. Of 120 patients interviewed most preferred to be treated with injections for almost any complaint. Patient demand for injections was felt to be a problem in 85% of the health facilities and may have contributed to overprescription of injectables. Consensus treatment and sterilization guidelines as well as a health education programme were developed and introduced to all health workers through seminars.

Effects of nitrogen on accumulation and partitioning of dry matter and nitrogen of vegetables. 3. Spinach

Four greenhouse and 2 field experiments (the latter on a sandy soil) were carried out with different amounts and dates of N application to analyse the dynamics of dry matter and N accumulation in spinach (cv. Trias). Frequent measurements were carried out on dry matter and N accumulation in leaf blades, petioles and stems. The total accumulation of dry matter and N differed largely among and within experiments. Increasing N application increased yield of dry matter and N accumulation, whereas splitting N applications had much smaller effects. However, the partitioning of dry matter and N proved insensitive to N treatments. Harvest indices for dry matter (about 0.67) or N (about 0.74) of crops at a marketable stage were fairly constant over treatments and experiments. Increasing or splitting the N application affected N accumulation more than dry matter production, resulting in large effects on N concentrations. The lack of variation in response to N for different N regimes facilitates the development of N application techniques aimed at high yield, high quality and reduced emissions. The organic N concentration of leaf blades and petioles decreased with leaf age, although in most experiments this decrease was smaller at higher leaf numbers. The nitrate-N concentration decreased with increasing leaf number at any sampling date; it was higher when N was abundant. High yields in autumn crops were associated with high nitrate concentrations but also with potentially high losses of N.

Contaminant-induced immunotoxicity in harbour seals: wildlife at risk?

Persistent, lipophilic polyhalogenated aromatic hydrocarbons (PHAHs) accumulate readily in the aquatic food chain and are found in high concentrations in seals and other marine mammals. Recent mass mortalities among several marine mammal populations have been attributed to infection by morbilliviruses, but a contributing role for immunotoxic PHAHs, including the polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins (PCDDs), and polychlorinated dibenzofurans (PCDFs) was not ruled out. We addressed this issue by carrying out a semi-field study in which captive harbour seals were fed herring from either the relatively uncontaminated Atlantic Ocean or the contaminated Baltic Sea for 2 years. We present here an overview of results obtained during this study. An impairment of natural killer (NK) cell activity, in vitro T-lymphocyte function, antigen-specific in vitro lymphocyte proliferative responses, and in vivo delayed-type hypersensitivity and antibody responses to ovalbumin was observed in the seals fed the contaminated Baltic herring. Additional feeding studies in PVG rats using the same herring batches suggested that an effect at the level of the thymus may be responsible for changes in cellular immunity, that virus-specific immune responses may be impaired, and that perinatal exposure to environmental contaminants represents a greater immunotoxic threat than exposure as a juvenile or adult. Together with the pattern of TCDD toxic equivalents of different PHAHs in the herring, these data indicate that present levels of PCBs in the aquatic food chain are immunotoxic to mammals. A review of contaminant levels in free-ranging harbour seals inhabiting polluted areas of Europe and North America suggests that many populations may be at risk to immunotoxicity. This could result in diminished host resistance and an increased incidence and severity of infectious disease.