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.

Progression and regression of the atherosclerotic plaque

In animals in which atherosclerosis was induced experimentally (by a high cholesterol diet) regression of the atherosclerotic lesion was demonstrated after serum cholesterol was reduced by cholesterol- lowering drugs or a low-fat diet. Whether regression of advanced coronary arterly lesions also takes place in humans after a similar intervention remains conjectural. However, several randomized studies, primarily employing lipid-lowering intervention or comprehensive changes in lifestyle, have demonstrated, using serial angiograms, that it is possible to achieve less progression, arrest or even (small) regression of atherosclerotic lesions. The lipid-lowering trials (NHBLI, CLAS, POSCH, FATS, SCOR and STARS) studied 1240 symptomatic patients, mostly men, with moderately elevated cholesterol levels and moderately severe angiographic-proven coronary artery disease. A variety of lipid-lowering drugs, in addition to a diet, were used over an intervention period ranging from 2 to 3 years. In all but one study (NHBLI), the progression of coronary atherosclerosis was less in the treated group, but regression was induced in only a few patients. The overall relative risk of progression of coronary atherosclerosis was 0 x 62 and 2 x 13, respectively. The induced angiographic differences were small and did not produce any significant haemodynamic benefit. The most important result was tht the disease process could be stabilized in the majority of patients. Three comprehensive lifestyle change trials (the Lifestyle Heart study, STARS and the Heidelberg Study) studied 183 patients, who were subjected to stress management, and/or intensive exercise, in addition to a low fat diet, over a period ranging from 1 to 3 years. All three trials demonstrated less progression, and more regression with overall relative risks of 0 x 40 and 2 x 35 respectively, in the intervention groups. Angiographic trials demonstrated that retardation or arrest of coronary atherosclerosis was possible after an intervention, but the ultimate goal, regression of the lesion, was only achieved in a small number of patients. However, the ability to stabilize coronary atherosclerosis is a considerable achievement for those patients with coronary atherosclerosis.

Gene diversity at allozyme loci in the cottonwood leaf beetle, Chrysomela scripta

Gene diversity was studied in beetles collected from a poplar plantation at Ames, Iowa. The beetles are widely distributed throughout North America wherever poplars (Populus spp) occur. Of 38 loci interpretable by simple Mendelian criteria, 22 were polymorphic (58%). Nei's mean heterozygosity per locus was 20.1 +/- 4.0%. A mean 2.29 +/- 1.35 alleles per locus was detected. The foregoing levels of diversity are typical of Coleoptera. There were significant deviations from Hardy-Weinberg expectations at six loci, and of these loci, four deviations were judged to have been caused by technical problems in resolving heterozygotes. Twelve polymorphic loci are considered suitable to carry out studies on the breeding structure of this important pest.

The results of denatured homologous vein grafts as conduits for secondary haemodialysis access surgery

OBJECTIVES

To determine the value of denatured homologous vein grafts as a conduit for secondary haemodialysis access.

DESIGN

Retrospective clinical study.

SETTING

2 University Hospitals.

MATERIALS AND METHODS

One-hundred-and-twenty-five patients received 195 grafts over a period of five years. Fifty-six first grafts (45%) functioned without complications throughout the study period of 5.8 years.

MAIN RESULTS

Primary patency was 57% after 1 year and 25% after 3 years of follow-up. Of the initial grafts, 69 (55%) needed 161 interventions, for thrombosis (n = 59), stenosis (n = 43), failure beyond repair (n = 40), aneurysm (n = 12), infection (n = 4), steal syndrome (n = 1), and other causes (n = 2). Secondary patency was 76% at 1 year and 52% at 3 years of follow-up. A major advantage of these grafts was the low rate (2.6%) of infection. Aneurysm formation occurred 17 times in 195 grafts (8.7%).

CONCLUSIONS

Denatured homologous vein graft is a good alternative in secondary access surgery.

Von Hippel-Lindau disease: new strategies in early detection and treatment

Von Hippel-Lindau disease is an autosomal dominant inherited disorder causing hemangioblastomas of the central nervous system (CNS), retinal hemangiomas, renal cell carcinomas, pheochromocytomas, pancreatic and liver cysts, and epididymal cystadenomas.

PURPOSE

Since 1976, we have periodically screened for the lesions in a large affected family and were able to evaluate new strategies in detection and treatment.

PATIENTS AND METHODS

A total of 23 individuals underwent the screening program. A multidisciplinary team of physicians was involved.

RESULTS

In 13 patients (7 females and 6 males), a total of 31 tumors was detected; hemangioblastoma of the CNS (9), retinal angioma (4), renal involvement (8), pheochromocytoma (4), pancreatic lesions (4), and liver lesions (2) were diagnosed by periodic family screening. On the basis of more than 10 years of experience and current literature, new criteria for diagnosis and treatment have been proposed.

CONCLUSION

The von Hippel-Lindau disease gene appears to be a tumor suppressor gene, and its absence or a defect in its structure is responsible for the predisposition to the disease. Tumor development depends on a somatic second mutation in the homologous allele. That means, in disease-gene carriers, tumor growth may begin at any age. Most of the lesions can be treated successfully when diagnosed in time. Periodic screening by a multidisciplinary team has to be continued lifelong.

Changes in blood transfusion practices after the introduction of consensus guidelines in Mwanza region, Tanzania

OBJECTIVE

To assess the effect of introducing consensus guidelines on avoidable blood transfusions in Mwanza region, Tanzania.

METHODS

Avoidable blood transfusions were determined among 842 blood transfusion recipients in eight hospitals in 1991. In a workshop with senior health workers from the region, consensus guidelines for the prescription of blood transfusions were developed and introduced in the hospitals and after 7 months intervention data were collected on 1042 blood transfusion recipients. The 1991 and 1992 data were compared to estimate the change in the proportion of avoidable blood transfusions.

RESULTS

In blood transfusion recipients aged < 5 years there was a significant reduction in the proportion of avoidable blood transfusions from 257 (52%) out of 498 to 197 (33%) out of 595 (P < 0.001), especially at the peripheral hospitals. For children the proportion decreased from 25 to 17% (P < 0.05) and for operated patients the percentage remained at 24%. In pregnant women there was a significant increase in the proportion of avoidable blood transfusions from 10 to 27% and in adults from 37 (25%) out of 146 to 121 (50%) out of 242. The improvement in peripheral hospitals was offset by a similar deterioration in the referral hospital, thus no overall reduction was achieved in the proportion of avoidable blood transfusions.

CONCLUSION

The development and introduction of consensus guidelines was not sufficient to change prescribing practice. The proportion of avoidable blood transfusions decreased only in hospitals where compliance was maintained through regular clinic meetings and strict supervision by senior medical staff.