Combined analyses and extended follow-up of two randomized controlled homocysteine-lowering B-vitamin trials

OBJECTIVES

In the Norwegian Vitamin Trial and the Western Norway B Vitamin Intervention Trial, patients were randomly assigned to homocysteine-lowering B-vitamins or no such treatment. We investigated their effects on cardiovascular outcomes in the trial populations combined, during the trials and during an extended follow-up, and performed exploratory analyses to determine the usefulness of homocysteine as a predictor of cardiovascular outcomes.

DESIGN

Pooling of data from two randomized controlled trials (1998-2005) with extended post-trial observational follow-up until 1 January 2008.

SETTING

Thirty-six hospitals in Norway.

SUBJECTS

6837 patients with ischaemic heart disease.

INTERVENTIONS

One capsule per day containing folic acid (0.8 mg) plus vitamin B12 (0.4 mg) and vitamin B6 (40 mg), or folic acid plus vitamin B12, or vitamin B6 alone or placebo.

MAIN OUTCOME MEASURES

Major adverse cardiovascular events (MACEs; cardiovascular death, acute myocardial infarction or stroke) during the trials and cardiovascular mortality during the extended follow-up.

RESULTS

Folic acid plus vitamin B12 treatment lowered homocysteine levels by 25% but did not influence MACE incidence (hazard ratio, 1.07; 95% CI, 0.95-1.21) during 39 months of follow-up, or cardiovascular mortality (hazard ratio, 1.12; 95% CI, 0.95-1.31) during 78 months of follow-up, when compared to no such treatment. Baseline homocysteine level was not independently associated with study outcomes. However, homocysteine concentration measured after 1-2 months of folic acid plus vitamin B12 treatment was a strong predictor of MACEs.

CONCLUSION

We found no short- or long-term benefit of folic acid plus vitamin B12 on cardiovascular outcomes in patients with ischaemic heart disease. Our data suggest that cardiovascular risk prediction by plasma total homocysteine concentration may be confined to the homocysteine fraction that does not respond to B-vitamins.

Genetic epidemiology of BRCA1 mutations in Norway

Familial breast-ovarian cancer has been demonstrated to be frequent but unevenly distributed in Norway. This was assumed to be caused by the reduced population size created by the medieval Bubonic plagues 25 generations ago, and by the following rapid expansion. We have previously reported that four mutations account for 68% of the BRCA1 mutation carriers. Subsequent analysis has resulted in a total of 100 separate families carrying one of these founder mutations. The four mutations occurred on one specific BRCA1 haplotype each. The 1675delA, 816delGT and 3347delAG families originated from the South-West coast of Norway with a few families in the north, while the traceable ancestors of the 1135insA families clustered along the historical inland road from the South-East to mid-Norway. The carriers of each of the four mutations today are descendants of one or a few individuals surviving the plagues. We may identify the majority of BRCA1 mutation carriers in Norway by screening for local founder mutations.

Presence of IgM in cutaneous mucus, but not in gut mucus of Atlantic salmon, Salmo salar. Serum IgM is rapidly degraded when added to gut mucus

In the first part of this study, cutaneous mucus of Atlantic salmon (Salmo salar) was shown to contain IgM, i.e. molecules composed of approximately 72 and 27 kDa subunits and reactive with polyclonal antisera and monoclonal antibodies made against serum IgM. Attempts to detect IgM-like molecules in gut mucus were negative, indicating the IgM is present, at best, in very small amounts. The degradation of serum IgM in mucosal secretions was examined in the second part of this study. Purified IgM from serum was rapidly digested in gut mucus at 4 degrees C. Intermediate 58, 52, 38, 35, 33 and 18 kDa breakdown fragments appeared when analysed in immunoblots. The transient fragments were further degraded to small fragments. HPLC analysis showed that only half of the added serum IgM was intact after 30 min of digestion, and after 4 h intact IgM could not be detected. Serum IgM was not degraded in cutaneous mucus, even after 17 h of incubation.

[Organization and management of Norwegian intensive care units]

BACKGROUND

A survey of organisational and managerial aspects in Norwegian intensive care units (ICU) was made six months after Standards for Intensive Care, a document setting out guidelines for the organisation and management of intensive care units, had been issued by the Norwegian Medical Association to Norwegian hospitals.

MATERIAL AND METHODS

298 questionnaires were sent to hospital managers and heads of clinical departments in 58 Norwegian hospitals.

RESULTS

The overall response rate was 77%. 60% of the respondents had heard about Standards, 44% had read them, 15% used them. The majority of ICUs were run by the Department of Anaesthesia. 75% answered that the admitting department had the overall responsibility for the individual patient; 23% of respondents claimed that the ICU doctor was responsible. More than half of these worked in secondary and tertiary care hospitals.

INTERPRETATION

Standards of Intensive Care is poorly known and read by less than half of the respondents. Only a few have started to implement them. Some uncertainty about patient responsibility may exist particularly in secondary and tertiary care hospitals. There seems to be a need for better role clarification and definitions of responsibility for all participants in intensive care, with more focus on organisational and managerial aspects.

[Activities and staffing in intensive care units in Norway--still need of better registration]

BACKGROUND

Standards in Intensive Care Medicine were approved by the Board of the Norwegian Medical Association in 1997. Their purpose is to clarify issues of responsibility, accountability and management in intensive care units. It also gives recommendations on management, staffing, education and resources.

MATERIAL AND METHODS

In order to obtain a reference point for any future assessment of the impact of the Standards document, a survey was carried out, addressing work load, medical staff, and questions of accountability, responsibility and cooperation.

RESULTS

16 hospitals responded (76%). The results seem to indicate that medical staff in relation to work load is smaller than recommended. It also seems that junior doctors only to a small extent are present in the intensive care units during ordinary working hours, and consequently have little opportunity to learn from working with experienced colleagues. However, both conclusions, especially the first one, are not entirely reliable, as close examination of the answers indicate that important concepts concerning the description of work load and staffing are poorly defined, and that the monitoring of work load is insufficient.

INTERPRETATION

It is concluded that staffing and work load in intensive care units are still insufficiently defined and monitored. The training environment for specialists is not optimal.

Identification of Renibacterium salmoninarum surface proteins by radioiodination

Surface exposed proteins of Renibacterium salmoninarum were identified by radiolabelling whole bacterial cells with 125I, followed by SDS-PAGE and autoradiography. The most prominent bands had molecular masses of approximately 57 kDa and 22 kDa; in addition, some less intensively labelled bands were detected. Polyclonal sera raised against the 22 kDa protein did not react with the 57 kDa protein. N-terminal amino acid sequence analysis of the purified 22 kDa protein showed no similarity with the sequence of the 57 kDa protein.

A termination mutant prevalent in Norwegian haplotype 7 phenylketonuria genes

RFLPs in the phenylalanine hydroxylase (PAH) gene locus were determined in 47 Norwegian nuclear families that had at least one child with phenylketonuria (PKU). The PKU haplotype distribution differed somewhat from that of other European populations. Mutant haplotype 7 is relatively rare in other populations but constituted 20% of all mutant haplotypes in Norway. In 14 of the 17 mutant haplotypes 7, a previously unreported deletion of the BamHI restriction site in exon 7 of the PAH gene was observed. The abrogation of the BamHI site was shown to be due to a G-to-T transversion, changing Gly 272 to Ter 272 in exon 7 of the gene, thus directly identifying the PKU mutation. Unlike the families of the other PKU patients, the families with this mutation clustered along the southeastern coast of Norway, suggesting a founder effect for this mutation.

Strut fracture in the new Bjørk-Shiley mitral valve prosthesis

The case of a patient with the new type Bjørk-Shiley aortic and mitral valve prosthesis is described. Three months after implant she suffered acute heart failure and died. Post-mortem examination revealed a fractured outlet strut in the mitral valve prosthesis with dislocation of the disc. The fracture was regarded as due to excessive brittleness caused by demonstrated deposition of chromium-tungsten-carbide.

Neurogenic intermittent claudication in association with spondylolisthesis

In the last three decades, more attention has been put upon neurogenic intermittent claudication, also called pseudoclaudication. The syndrome usually develops in patients with congenital narrow spinal canal and secondary additional narrowing. Two cases of spondylolisthesis with neurogenic intermittent claudication are presented. The pathogenesis, symptoms and findings of neurogenic intermittent claudication are discussed.