Reduced cardiac conduction velocity and predisposition to arrhythmias in connexin40-deficient mice

Intercellular channels of gap junctions are formed in vertebrates by the protein family of connexins and allow direct exchange of ions, metabolites and second messenger molecules between apposed cells (reviewed in [1-3]). In the mouse, connexin40 (Cx40) protein has been detected in endothelial cells of lung and heart and in certain heart muscle cells: atrial myocytes, cells of the atrial ventricular (AV) node and cells of the conductive myocardium, which conducts impulses from the AV node to ventricular myocyctes [3]. We have generated mice homozygous for targeted disruption of the Cx40 gene (Cx40-/-mice). The electrocardiograph (ECG) parameters of Cx40-/- mice were very prolonged compared to those of wild type (Cx40+/+) mice, indicating that Cx40-/- mice have lower atrial and ventricular conduction velocities. For 6 out of 31 Cx40-/- animals, different types of atrium-derived abnormalities in cardiac rhythm were recorded, whereas continuous sinus rhythm was observed for the 26 Cx40+/+ and 30 Cx40+/- mice tested. The expression levels of other connexins expressed in heart (Cx37, Cx43 and Cx45) were the same in Cx40-/- and Cx40+/+ mice. Our results demonstrate the function of Cx40 in the regulation and coordination of heart contraction and show that cardiac arrhythmogenesis can not only be caused by defects in the ion channels primarily involved in cellular excitation but also by defects in intercellular communication through gap junction channels. As the distribution of Cx40 protein is similar in mouse and human hearts, further functional analysis of Cx40 should yield relevant insights into arrhythmogenesis in human patients.

Prevalence of thyroid disease, thyroid dysfunction and thyroid peroxidase antibodies in a large, unselected population. The Health Study of Nord-Trondelag (HUNT)

OBJECTIVE

To examine the prevalence of thyroid disease and dysfunction including thyroid autoimmunity in Norway.

MATERIALS AND METHODS

All inhabitants 20 years and older (94009) in Nord-Trondelag were invited to participate in a health survey with a questionnaire and blood samples.

RESULTS

The prevalence of former diagnosed hyperthyroidism was 2.5% in females and 0.6% in males, hypothyroidism 4.8% and 0.9%, and goitre 2.9% and 0.4% respectively. In both sexes the prevalence increased with age. In individuals without a history of thyroid disease the median, 2.5 and 97.5 percentiles for TSH (mU/l) were 1.80 and 0.49-5.70 for females and 1. 50 and 0.56-4.60 for males. The TSH values increased with age. When excluding individuals with positive thyroid peroxidase antibodies (TPOAb) (>200U/ml), the 97.5 percentiles dropped to 3.60 mU/l and 3. 40 mU/l respectively. The prevalence of pathological TSH values in females and males were TSH >/=10mU/l 0.90% and 0.37%; TSH 4.1-9. 9mU/l 5.1% and 3.7%; and TSH</=0.05mU/l 0.45% and 0.20% respectively. The prevalence of positive TPOAb (>200U/ml) was 13.9% in females and 2.8% in males. In females the lowest percentage (7.9%) of positive TPOAb was seen with TSH 0.2-1.9mU/l and increased both with lower and higher levels of TSH. The percentage of males with positive TPOAb was lower than in females in all TSH groups except for those with TSH>10mU/l (85% TPOAb positive).

CONCLUSIONS

In spite of a high prevalence of recognised thyroid disease in the population a considerable number of inhabitants have undiagnosed thyroid dysfunction and also positive TPOAb.

Impaired conduction of vasodilation along arterioles in connexin40-deficient mice

Connexins have been hypothesized to play an important role in intercellular communication within the vascular wall and may provide a mechanistic explanation for conduction of vasomotor responses. To test this hypothesis, we studied the transmission of vasomotor responses in the intact skeletal muscle microcirculation of connexin40-deficient mice (Cx40(-/-)). Arterioles were locally stimulated with hyperpolarizing dilators (acetylcholine [ACh] as well as bradykinin [Bk]) or depolarizing K(+) solution, and the resulting changes in diameter were measured using a videomicroscopy technique at the site of application and up to 1.32 mm upstream. Arterial pressure was elevated 25% in Cx40(-/-) mice (94+/-5 versus 75+/-4 mm Hg). Vessels selected for study had equivalent basal diameter and vasomotor tone in both genotypes of mice. Vasomotion was present in small arterioles of both genotypes, but its intensity was exaggerated in Cx40(-/-) mice. ACh and Bk induced dilation (33% and 53%, respectively, of maximal response) at the site of application that was of similar magnitude in both genotypes. These dilations were observed to spread upstream within <1 second without significant attenuation in Cx40(+/+) mice. However, spreading was severely attenuated in Cx40(-/-) animals (11+/-4% versus 35+/-7% with ACh and 38+/-5% versus 60+/-7% with Bk in Cx40(-/-) and Cx40(+/+), respectively; P<0.05). In contrast, conducted vasoconstrictions, induced by K(+) solution decreased equally with distance in both genotypes. These results support a significant role for Cx40 in vascular intercellular communication. Our observations indicate that Cx40 is required for normal transmission of endothelium-dependent vasodilator responses and may underlie altered vasomotion patterns.

Defective vascular development in connexin 45-deficient mice

In order to reveal the biological function(s) of the gap-junction protein connexin 45 (Cx45), we generated Cx45-deficient mice with targeted replacement of the Cx45-coding region with the lacZ reporter gene. Heterozygous Cx45(+/)(−) mice showed strong expression of the reporter gene in vascular and visceral smooth muscle cells. Cx45-deficient embryos exhibited striking abnormalities in vascular development and died between embryonic day (E) 9.5 and 10.5. Differentiation and positioning of endothelial cells appeared to be normal, but subsequent development of blood vessels revealed impaired formation of vascular trees in the yolk sac, impaired allantoic mesenchymal ingrowth and capillary formation in the labyrinthine part of the placenta, and arrest of arterial growth, including a failure to develop a smooth muscle layer surrounding the major arteries of the embryo proper. As a consequence, the hearts of most Cx45-deficient embryos were dilated. The abnormal development of the vasculature in the yolk sac of Cx45(−)(/)(−) embryos could be caused by defective TGFbeta signalling, as the amount of TGF beta1 protein in the epithelial layer of the yolk sac was largely decreased in the E9.5 Cx45(−)(/)(−) embryo, compared with the wild-type embryo. The defective vascular development was accompanied by massive apoptosis, which began in some embryos at E8.5 and was abundant in virtually all tissues of the embryos at E9.5. We conclude that in Cx45(−)(/)(−) embryos, vasculogenesis was normal, but subsequent transformation into mature vessels was interrupted. Development of different types of vessels was impaired to a varying extent, which possibly reflects the complementation by other connexin(s).

Endothelium-specific replacement of the connexin43 coding region by a lacZ reporter gene

The murine gap junction protein connexin43 (Cx43) is expressed in blood vessels, with vastly different contribution by endothelial and smooth muscle cells. We have used the Cre recombinase under control of TIE2 transcriptional elements to inactivate a floxed Cx43 gene specifically in endothelial cells. Cre-mediated deletion led to replacement of the Cx43 coding region by a lacZ reporter gene. This allowed us to monitor the extent of deletion and to visualize the endothelial expression pattern of Cx43. We found widespread endothelial expression of the Cx43 gene during embryonic development, which became restricted largely to capillaries and small vessels in all adult organs examined. Mice lacking Cx43 in endothelium did not exhibit altered blood pressure, in contrast to mice deficient in Cx40. Our results show that lacZ activation after deletion of the target gene allows us to determine the extent of cell type-specific deletion after phenotypical investigation of the same animal.

Rapid changes in the prevalence of obesity and known diabetes in an adult Norwegian population. The Nord-Trøndelag Health Surveys: 1984-1986 and 1995-1997

OBJECTIVE

To determine whether changes in mean BMI and the prevalence of obesity in a total adult population during a short (11-year) period were associated with changes in the prevalence of diabetes.

RESEARCH DESIGN AND METHODS

This study involved cross-sectional surveys of all inhabitants aged > or = 20 years of the county of Nord-Trøndelag from 1984 to 1986 (n = 85,100) and from 1995 to 1997 (n = 92,434). Attendance rates were 88.1 and 71.3%, respectively, and 90.0% in an additional survey of people aged 13-19 years from 1995 to 1997 (n = 9,593). Main outcome measures were age-specific mean BMI for the diabetic and nondiabetic subgroups and the prevalence of obesity and diabetes. For comparison, mean BMIs from 18 of 19 Norwegian counties for the group aged 40-42 years were examined.

RESULTS

Mean BMI increased from 27.2 to 29.0 kg/m2 in the diabetic population and from 25.1 to 26.3 kg/m2 in the nondiabetic population. The BMI distribution curve shifted to the right, but homogeneity was also reduced. A comparison with other Norwegian counties indicated that this increase occurred during the last 6 years between the surveys. The prevalence of obesity (BMI > or = 30 kg/m2) increased from 7.5 to 14% in nondiabetic men and from 13 to 18% in nondiabetic women. The increase was particularly great in men aged < 60 years and in women aged < 50 years. The overall prevalence of known diabetes increased between the two surveys (from 2.9 to 3.2%) but only in men. The largest increase was observed in the corresponding younger sex and age-groups.

CONCLUSIONS

A substantial increase in mean BMI and the prevalence of obesity occurred in the younger age-groups at the same time as an increase in the prevalence of diabetes. A greater increase in diabetes prevalence in this ethnically stable Western European population may follow if effective primary preventive strategies are not undertaken.

Change in height, weight and body mass index: Longitudinal data from the HUNT Study in Norway

OBJECTIVE

The aim of this study was to analyse changes in body weight and height, and the changes in the prevalence of overweight and obesity.

DESIGN

Prospective population based study with 11-year follow-up.

SUBJECTS

Norwegian men (n=21565) and women (n=24337) aged 20 years or more who participated in two health surveys, the first in 1984-1986 and the other in 1995-1997.

MEASUREMENTS

Height and weight were measured by using standardised procedures at both surveys, and we computed body mass index (BMI) as weight in kilo divided by the squared value of height in meters.

RESULTS

Participants who were younger than 50 years at the first survey showed a large increase in body weight, and men and women aged 20-29 years increased their weight with an average of 7.9 kg and 7.3 kg, respectively. Contradictory, participants who were 70 years or older had on average a weight loss. The prevalence of overweight (BMI=25.0-29.9 kg/m(2)) and obesity (BMI>/=30 kg/m(2)) increased between the surveys, especially in the youngest age groups. Overall, the proportion classified as obese increased from 6.7 to 15.5% among men and from 11.0 to 21.0% among women. Some of this increase was due to a reduction in height, which was most pronounced in the oldest age groups.

CONCLUSION

During approximately 10 years, body weight increased in all age groups below 70 years, and the prevalence of overweight and obese persons was approximately 20% higher at the second survey compared with the first survey.

Sewage sludge ash--A promising secondary phosphorus source for fertilizer production

Sewage sludge incineration is extensively practiced in some European countries such as the Netherlands, Switzerland, Austria and Germany. A survey of German sewage sludge ash showed that the recovery potential is high, approx. 19,000 t of phosphorus per year. However, the survey also discovered that the bioavailability of phosphorus in the sewage sludge ash is poor and that more than half of the ashes cannot be used as fertilizers due to high heavy metal content. A new thermochemical process for sewage sludge ash treatment was developed that transforms the ash into marketable fertilizer products. Sewage sludge ash was thermochemically treated with sodium and potassium additives under reducing conditions, whereby the phosphate-bearing mineral phases were transformed into plant available phosphates. High P-bioavailability was achieved with a molar Na/P ratio >1.75 in the starting materials. Sodium sulfate, carbonate and hydroxide performed comparably as additives for this calcination process. Potassium carbonate and -hydroxide have to be added in a molar K/P ratio >2.5 to achieve comparable P-solubility. The findings of the laboratory scale investigations were confirmed by an industrial demonstration trial for an ash treatment with sodium sulfate. Simultaneously, the volatile transition metal arsenic (61% removal) as well as volatile heavy metals such as cadmium (80%), mercury (68%), lead (39%) and zinc (9%) were removed via the off-gas treatment system. The product of the demonstration trial is characterized by high bioavailability and a toxic trace element mass fraction below the limit values of the German fertilizer ordinance, thus fulfilling the quality parameters for a P-fertilizer.

Olfactory kin recognition in a songbird

The ability to recognize close relatives in order to cooperate or to avoid inbreeding is widespread across all taxa. One accepted mechanism for kin recognition in birds is associative learning of visual or acoustic cues. However, how could individuals ever learn to recognize unfamiliar kin? Here, we provide the first evidence for a novel mechanism of kin recognition in birds. Zebra finch (Taeniopygia guttata) fledglings are able to distinguish between kin and non-kin based on olfactory cues alone. Since olfactory cues are likely to be genetically based, this finding establishes a neglected mechanism of kin recognition in birds, particularly in songbirds, with potentially far-reaching consequences for both kin selection and inbreeding avoidance.

Cuckoos, cowbirds and hosts: adaptations, trade-offs and constraints

The interactions between brood parasitic birds and their host species provide one of the best model systems for coevolution. Despite being intensively studied, the parasite-host system provides ample opportunities to test new predictions from both coevolutionary theory as well as life-history theory in general. I identify four main areas that might be especially fruitful: cuckoo female gentes as alternative reproductive strategies, non-random and nonlinear risks of brood parasitism for host individuals, host parental quality and targeted brood parasitism, and differences and similarities between predation risk and parasitism risk. Rather than being a rare and intriguing system to study coevolutionary processes, I believe that avian brood parasites and their hosts are much more important as extreme cases in the evolution of life-history strategies. They provide unique examples of trade-offs and situations where constraints are either completely removed or particularly severe.

Spatiotemporal transcription of connexin45 during brain development results in neuronal expression in adult mice

Characterization of the expression pattern of connexins in neural tissue is a necessary prerequisite for understanding the functional relevance of the corresponding gap junction channels in brain. Here we describe the cell type-specific expression of connexin45 in the CNS and the spatiotemporal expression pattern from embryonic day 19.5 to adult brain using a recently described connexin45 LacZ-reporter mouse. The connexin45 gene is highly expressed during embryogenesis and up to 2 weeks after birth in nearly all brain regions. Afterward its expression is restricted to the thalamus, the CA3 region of hippocampus and the cerebellum. In adult mouse brain, the pattern of LacZ-staining in combination with the analysis of different neuronal and glial marker proteins strongly suggests that connexin45 is expressed in neurons, but presumably not in astrocytes or mature oligodendrocytes. Expression of the LacZ/connexin45 reporter gene in subsets of neurons, such as cerebral cortical, hippocampal and thalamic neurons as well as basket and stellate cells of cerebellum should be corroborated by functional investigations of connexin45 protein in electrical synapses. Based on its expression pattern during development, we suggest that the connexin45-containing gap junction channels have a rather ubiquitous role during brain development and may contribute to functional specification in certain subsets of neurons in the adult brain.

The evolution of cuckoo parasitism: a comparative analysis

Cuckoos (family Cuculidae) show the highest diversity of breeding strategies within one bird family (parental care, facultative and obligate brood parasites). We used independent contrasts from two phylogenies to examine how this variation was related to 13 ecological and life-history variables. The ancestral state was probably tropical, resident, forest cuckoos with parental care. The evolution of brood parasitism was correlated with a shift to more open habitats, a change in diet, increases in species breeding-range size and migration, and a decrease in egg size. Once parasitism had evolved, more elaborate parasitic strategies (more harmful to host fitness) were correlated with decreased egg size, a change in diet, increased breeding-range size and migration, a shortened breeding season and a decrease in local abundance. Establishing the most probable evolutionary pathways, using the method of Pagel, shows that changes in ecological variables (such as migration, range size and diet type) preceded the evolution of brood parasitism, which is likely to be a later adaptation to reduce the cost of reproduction. By contrast, brood parasitism evolved before changes in egg size occurred, indicating that egg size is an adaptive trait in host--parasite coevolution. Our results suggest that the evolution of cuckoo brood parasitism reflects selection from both ecological pressures and host defences.

Abnormal cardiac conduction and morphogenesis in connexin40 and connexin43 double-deficient mice

Connexin40-deficient (Cx40(-/-)/Cx43(+/+)) and connexin43-heterozygous knockout mice (Cx40(+/+)/Cx43(+/-)) are viable but show cardiac conduction abnormalities. The ECGs of adult double heterozygous animals (Cx40(+/-)/Cx43(+/-)) suggest additive effects of Cx40 and Cx43 haploinsufficiency on ventricular, but not on atrial, conduction. We also observed additive effects of both connexins on cardiac morphogenesis. Approximately half of the Cx40(-/-)/Cx43(+/+) embryos died during the septation period, and an additional 16% died after birth. The majority of the latter mice had cardiac hypertrophy in conjunction with common atrioventricular junction or a ventricular septal defect. All Cx40(-/-)/Cx43(+/-) progeny exhibited cardiac malformations and died neonatally. The most frequent defect was common atrioventricular junction with abnormal atrioventricular connection, which was more severe than that seen in Cx40(-/-)/Cx43(+/+) mice. Furthermore, muscular ventricular septal defects, premature closure of the ductus arteriosus, and subcutaneous edema were noticed in these embryos. Cx40(+/-)/Cx43(-/-) embryos showed the same phenotype (ie, obstructed right ventricular outflow tract) as reported for Cx40(+/+)/Cx43(-/-) mice. These findings demonstrate that Cx43 haploinsufficiency aggravates the abnormalities observed in the Cx40(-/-) phenotype, whereas Cx40 haploinsufficiency does not worsen the Cx43(-/-) phenotype. We conclude that the gap-junctional proteins Cx40 and Cx43 contribute to morphogenesis of the heart in an isotype-specific manner.

Identification of incident stroke in Norway: hospital discharge data compared with a population-based stroke register

BACKGROUND AND PURPOSE

The validity of hospital discharge diagnoses is essential in improving stroke surveillance and estimating healthcare costs of stroke. The aim of this study was to assess sensitivity, positive predictive value, and accuracy of discharge diagnoses compared with a stroke register.

METHODS

A record linkage was made between a population-based stroke register and the discharge records of the hospital serving the population of the stroke register (n=70 000). The stroke register (including patients aged 15 and older and with no upper age limit), applied here as a "gold standard," was used to estimate sensitivity, positive predictive value, and accuracy of the discharge diagnoses classification. The length of stay in hospital by stroke patients was measured.

RESULTS

Identifying cerebrovascular diseases by hospital discharge diagnoses (International Classification of Diseases, 9th Revision [ICD-9], codes 430 to 438.9, first admission) lead to a substantial overestimation of stroke in the target population. Restricting the retrieval to acute stroke diagnoses (ICD-9 codes 430, 431, 434, and 436) gave an incidence estimate closer to the "true" incidence rate in the stroke register. Selecting ICD-9 codes 430 to 438 of cerebrovascular diseases gave the highest sensitivity (86%). The highest positive predictive value (68%) was achieved by selecting acute stroke diagnoses (ICD-9 codes 430, 431, 434, and 436), at the expense of a lower sensitivity (81%). Accuracy of ICD codes 430 to 438.9 (n=678) revealed the highest proportion of incident strokes identified by the acute stroke diagnoses (ICD-9 codes 430, 431, 434, and 436). Seventy-four percent of hospital discharge diagnoses classified as first-ever stroke kept the original diagnosis. Only 4.6% of the discharge diagnoses were classified as nonstroke diagnoses after validation. The estimation of length of stay in the hospital was improved by selection of acute stroke diagnoses from hospital discharge data (ICD-9 codes 430, 431, 434, and 436), which gave the same estimate of length of stay, a median of 8 days (2.5 percentile=0 and 97.5 percentile=56), compared with a median of 8 days (2.5 percentile=0 and 97.5 percentile=51) based on the stroke register.

CONCLUSIONS

Hospital discharge data may overestimate stroke incidence and underestimate the length of stay in the hospital, unless selection routines of hospital discharge diagnoses are restricted to acute stroke diagnoses (ICD-9 codes 430, 431, 434, and 436). If supplemented by a validation procedure, including estimates of sensitivity, positive predictive value, and accuracy, hospital discharge data may provide valid information on hospital-based stroke incidence and lead to better allocation of health resources. Distinguishing subtypes of stroke from hospital discharge diagnoses should not be performed unless coding practices are improved.

Host-parasite population genetics: a cross-sectional comparison of Bulinus globosus and Schistosoma haematobium

The genetic population structures of the freshwater snail Bulinus globosus and its trematode parasite Schistosoma haematobium from 8 river sites in the Zimbabwean highveld were compared using randomly amplified DNA (RAPD) markers. There was significant variability between snail populations collected at different sites, but schistosome populations only showed differentiation at a wider geographical scale (between 2 non-connected river systems). For snails, genetic distance was better correlated with proximity along rivers than absolute geographical separation. In contrast, schistosome genetic distance was better correlated with absolute geographical separation than proximity along rivers. These results are consistent with different dispersal mechanisms for snails and schistosomes and the implications for host-parasite coevolution are discussed.

Estimating adult sex ratios in nature

Adult sex ratio (ASR, the proportion of males in the adult population) is a central concept in population and evolutionary biology, and is also emerging as a major factor influencing mate choice, pair bonding and parental cooperation in both human and non-human societies. However, estimating ASR is fraught with difficulties stemming from the effects of spatial and temporal variation in the numbers of males and females, and detection/capture probabilities that differ between the sexes. Here, we critically evaluate methods for estimating ASR in wild animal populations, reviewing how recent statistical advances can be applied to handle some of these challenges. We review methods that directly account for detection differences between the sexes using counts of unmarked individuals (observed, trapped or killed) and counts of marked individuals using mark-recapture models. We review a third class of methods that do not directly sample the number of males and females, but instead estimate the sex ratio indirectly using relationships that emerge from demographic measures, such as survival, age structure, reproduction and assumed dynamics. We recommend that detection-based methods be used for estimating ASR in most situations, and point out that studies are needed that compare different ASR estimation methods and control for sex differences in dispersal.This article is part of the themed issue 'Adult sex ratios and reproductive decisions: a critical re-examination of sex differences in human and animal societies'.

Maladaptive mate choice maintained by heterozygote advantage

Common buzzards (Buteo buteo) show a plumage polymorphism that appears to be maintained by heterozygote advantage and allows a maladaptive form of mate choice to persist. The light and dark morphs have a much lower fitness than the presumed heterozygous intermediate morph, but are replenished through Mendelian segregation in intermediate-intermediate pairs. Light and dark morphs could maximize their fitness by mating light with dark to produce all intermediate offspring, but instead choose partners of their own color, thereby producing broods of minimally fit homozygotes. Such maladaptive behavior argues forcefully against mate choice based on "good genes," and its persistence is best explained by heterozygote advantage maintaining the polymorphism coupled with nongenetic mate choice based on sexual imprinting. Modeling different patterns of mate choice shows that random mating and preference for own morph fit our data poorly, whereas preference for mother's morph yields a good fit.

Complete survey of German sewage sludge ash

The amount of sewage sludge produced worldwide is expected to further increase due to rising efforts in wastewater treatment. There is a growing concern against its direct use as fertilizer due to contamination of the sludge with heavy metals and organic pollutants. Incinerating the sludge degrades organic compounds almost completely and concentrates heavy metals and phosphorus. However, the sewage sludge ash (SSA) is almost completely disposed of and with it all resources are removed from the economic cycle. Comprehensive knowledge of the composition of SSA is crucial to assess the resource recovery potentials. We conducted a survey of all SSA emerging in Germany and determined the respective mass fractions of 57 elements over a period of one year. The median content of phosphorus was 7.9%, indicating an important recovery potential. Important trace elements were Zn (2.5 g/kg), Mn (1.3 g/kg), and Cu (0.9 g/kg). Mass fractions of technology metals such as V, Cr, Ga, Nb, and rare earths were comparatively low. Considering the possible use of SSA as secondary raw material for fertilizer production it should be noted that its Cd and U content (2.7 mg/kg and 4.9 mg/kg respectively) is significantly lower than that of rock phosphate based mineral fertilizers.

Implementing clinical guidelines in the treatment of hypertension in general practice. Evaluation of patient outcome related to implementation of a computer-based clinical decision support system

OBJECTIVE

To evaluate the implementation of clinical guidelines for hypertension in general practice by use of a computer-based clinical decision support system (CDSS) and a specific implementation strategy. Evaluation of patient outcome.

DESIGN

Randomised study with health centres as units. The intervention group had the CDSS installed and made ready for use, doctors and assistants were trained and received a user-manual, the doctors were offered telephone repetitions, a seminar in risk intervention and, at the same seminar, further demonstration of the CDSS. The doctors received baseline registrations with information of how they treated their own hypertensive patients, and use of the CDSS was checked repeatedly.

SETTING

General practice in Sør- and Nord-Trøndelag counties in Norway, 380,000 inhabitants.

PARTICIPANTS

Seventeen health centres with 24 doctors and 984 patients in the intervention group. Data from 879 patients used in the final analyses. Twelve health centres with 29 doctors and 1255 patients in the control group. Data from 1119 patients used in the final analyses.

MAIN OUTCOME MEASURES

After an intervention period of 18 months, group differences in level of systolic and diastolic blood pressure, serum cholesterol, body mass index, and risk score for myocardial infarction were calculated, as well as group differences in fractions of smokers.

RESULTS

Significant group difference in favour of intervention group: diastolic blood pressure 1 mmHg (95% CI -1.89, -0.17). However, a significant baseline difference in systolic blood pressure in favour of control group of 2.7 mmHg (95% CI 1.0, 4.5) had been reduced to 1.2 mmHg (95% CI -0.6, 3.0) after intervention.

CONCLUSION

Implementation of clinical guidelines in the treatment of hypertensive patients in general practice by means of a CDSS and several other procedures for implementation did not affect patient outcome in any clinically significant way.

Recovery potential of German sewage sludge ash

Incineration of sewage sludge is expected to increase in the future due to growing concerns about the direct use of sludge in agriculture. Sewage sludge is the pollutant sink of wastewater treatment and thus loaded with contaminants that might pose environmental hazards. Incineration degrades organic pollutants efficiently, but since the ash is currently mostly disposed of, all valuable component like phosphorus (P) and technologically relevant metals present in the sewage sludge ash (SSA) are removed from the economic cycle entirely. We conducted a complete survey of SSA from German mono-incineration facilities and determined the theoretical recovery potential of 57 elements. German SSA contains up to 19,000 t/a P which equals approximately 13% of phosphorus applied in the German agriculture in form of phosphate rock based mineral fertilizers. Thus, SSA is an important secondary resource of P. However, its P-solubility in ammonium citrate solution, an indicator for the bioavailability, is only about 26%. Treatment of SSA is recommended to enhance P bioavailability and remove heavy metals before it is applied as fertilizer. The recovery potential for technologically relevant metals is generally low, but some of these elements might be recovered efficiently in the course of P recovery exploiting synergies.

Implementing clinical guidelines in the treatment of diabetes mellitus in general practice. Evaluation of effort, process, and patient outcome related to implementation of a computer-based decision support system

OBJECTIVES

To evaluate the implementation of clinical guidelines for diabetes mellitus in general practice with a specific computer-based clinical decision support system (CDSS) as part of the intervention.

METHODS

Randomized study with health center as unit. General practice in Sør- and Nord-Trøndelag counties in Norway, 380,000 inhabitants. Seventeen health centers with 24 doctors and 499 patients with diabetes mellitus were in the intervention group and 12 health centers with 29 doctors and 535 patients were in the control group. Main outcome measures were group differences in fractions of patients without registrations (process evaluation) and mean group differences for the same variables (patient outcome evaluation).

RESULTS

Statistically significant group differences were experienced for fractions of patients without registration of cigarette smoking (intervention group, 82.6%; control group 94.5%), body mass index (78.2% vs. 93.0%), and sufficient registrations for calculation of risk score for myocardial infarction (91.1% vs. 98.3%); all during 18 months. Large center variations were shown for all variables. The only statistically significant group difference was -2.3 mm Hg (95% CI, -3.8, -0.8) in diastolic blood pressure in favor of the intervention group. Statistically insignificant differences in favor of the intervention group were HbA1c, -0.1% (95% CI, -0.4, 0.1), systolic blood pressure, -1.2 mm Hg (95% CI, -4.4, 2.0). Statistically insignificant differences in favor of the control group were fractions of smokers, +3.0% (95% CI, -4.0, 10.0), body mass index, +0.3 kg/m2 (95% CI, -0.8, 1.4), risk score in female +0.1 (95% CI, -5.1, 5.2), and risk score in male +2.6 (95% CI, -14.2, 19.5).

CONCLUSIONS

Implementation of clinical guidelines for diabetes mellitus in general practice, by means of a CDSS and several procedures for implementation, did not result in a clinically significant change in doctors' behavior or in patient outcome.