Patient-reported outcome measures in hip fracture patients

Aims

The aims of this study were to assess quality of life after hip fractures, to characterize respondents to patient-reported outcome measures (PROMs), and to describe the recovery trajectory of hip fracture patients.

Methods

Data on 35,206 hip fractures (2014 to 2018; 67.2% female) in the Norwegian Hip Fracture Register were linked to data from the Norwegian Patient Registry and Statistics Norway. PROMs data were collected using the EuroQol five-dimension three-level questionnaire (EQ-5D-3L) scoring instrument and living patients were invited to respond at four, 12, and 36 months post fracture. Multiple imputation procedures were performed as a model to substitute missing PROM data. Differences in response rates between categories of covariates were analyzed using chi-squared test statistics. The association between patient and socioeconomic characteristics and the reported EQ-5D-3L scores was analyzed using linear regression.

Results

The median age was 83 years (interquartile range 76 to 90), and 3,561 (10%) lived in a healthcare facility. Observed mean pre-fracture EQ-5D-3L index score was 0.81 (95% confidence interval 0.803 to 0.810), which decreased to 0.66 at four months, to 0.70 at 12 months, and to 0.73 at 36 months. In the imputed datasets, the reduction from pre-fracture was similar (0.15 points) but an improvement up to 36 months was modest (0.01 to 0.03 points). Patients with higher age, male sex, severe comorbidity, cognitive impairment, lower income, lower education, and those in residential care facilities had a lower proportion of respondents, and systematically reported a lower health-related quality of life (HRQoL). The response pattern of patients influenced scores significantly, and the highest scores are found in patients reporting scores at all observation times.

Conclusion

Hip fracture leads to a persistent reduction in measured HRQoL, up to 36 months. The patients' health and socioeconomic status were associated with the proportion of patients returning PROM data for analysis, and affected the results reported. Observed EQ-5D-3L scores are affected by attrition and selection bias mechanisms and motivate the use of statistical modelling for adjustment.

Exploring variation in timely reperfusion treatment in ST-segment elevation myocardial infarction in Norway: a national register-based cohort study

OBJECTIVES

This study aimed to investigate determinants of reperfusion within recommended time limits (timely reperfusion) for ST-segment elevation myocardial infarction patients, exploring the impact of geography, patient characteristics and socio-economy.

DESIGN

National register-based cohort study.

SETTING

Multilevel logistic regression models were applied to examine the associations between timely reperfusion and residency in hospital referral areas and municipalities, patient characteristics, and socio-economy.

PARTICIPANTS

7607 Norwegian ST-segment elevation myocardial infarction patients registered in the Norwegian Registry of Myocardial Infarction during 2015-2018.

MAIN OUTCOME MEASURES

The odds of timely reperfusion by primary percutaneous coronary intervention (PCI) or fibrinolysis.

RESULTS

Among 7607 ST-segment elevation myocardial infarction patients in Norway, 56% received timely reperfusion. The Norwegian goal is 85%. While 81% of the patients living in the Oslo hospital referral area received timely reperfusion, only 13% of the patients living in Finnmark did so.Patients aged 75-84 years had lower odds of timely reperfusion than patients below 55 years of age (OR 0.73, 95% CI 0.61 to 0.87). Patients with moderate or high comorbidity had lower odds than patients without (OR 0.81, 95% CI 0.68 to 0.95 and OR 0.61, 95% CI 0.44 to 0.84). More than 2 hours from symptom onset to first medical contact gave lower odds than less than 30 min (OR 0.63, 95% CI 0.54 to 0.72). 1-2 hours of travel time to a PCI centre (OR 0.39, 95% CI 0.31 to 0.49) and more than 2 hours (OR 0.22, 95% CI 0.16 to 0.30) gave substantially lower odds than less than 1 hour of travel time.

CONCLUSIONS

The varying proportion of patients receiving timely reperfusion across hospital referral areas implies inequity in fundamental healthcare services, not compatible with established Norwegian health policy. The importance of travel time to PCI centre points at the expanded use of prehospital pharmacoinvasive strategy to obtain the goals of timely reperfusion in Norway.

Modifiable and non-modifiable risk factors in hip fracture mortality in Norway, 2014 to 2018 : a linked multiregistry study

Aims

This study aimed to identify risk factors (patient, healthcare system, and socioeconomic) for mortality after hip fractures and estimate their relative importance. Further, we aimed to elucidate mortality and survival patterns following fractures and the duration of excess mortality.

Methods

Data on 37,394 hip fractures in the Norwegian Hip Fracture Register from January 2014 to December 2018 were linked to data from the Norwegian Patient Registry, Statistics Norway, and characteristics of acute care hospitals. Cox regression analysis was performed to estimate risk factors associated with mortality. The Wald statistic was used to estimate and illustrate relative importance of risk factors, which were categorized in modifiable (healthcare-related) and non-modifiable (patient-related and socioeconomic). We calculated standardized mortality ratios (SMRs) comparing deaths among hip fracture patients to expected deaths in a standardized reference population.

Results

Mean age was 80.2 years (SD 11.4) and 67.5% (n = 25,251) were female. Patient factors (male sex, increasing comorbidity (American Society of Anesthesiologists grade and Charlson Comorbidity Index)), socioeconomic factors (low income, low education level, living in a healthcare facility), and healthcare factors (hip fracture volume, availability of orthogeriatric services) were associated with increased mortality. Non-modifiable risk factors were more strongly associated with mortality than modifiable risk factors. The SMR analysis suggested that cumulative excess mortality among hip fracture patients was 16% in the first year and 41% at six years. SMR was 2.48 for the six-year observation period, most pronounced in the first year, and fell from 10.92 in the first month to 3.53 after 12 months and 2.48 after six years. Substantial differences in median survival time were found, particularly for patient-related factors.

Conclusion

Socioeconomic, patient-, and healthcare-related factors all contributed to excess mortality, and non-modifiable factors had stronger association than modifiable ones. Hip fractures contributed to substantial excess mortality. Apparently small survival differences translate into substantial disparity in median survival time in this elderly population.

Cite this article: Bone Joint J 2022;104-B(7):884–893.

Waiting time for hip fracture surgery: hospital variation, causes, and effects on postoperative mortality : data on 37,708 operations reported to the Norwegian Hip fracture Register from 2014 to 2018

Aims

This study aimed to describe preoperative waiting times for surgery in hip fracture patients in Norway, and analyze factors affecting waiting time and potential negative consequences of prolonged waiting time.

Methods

Overall, 37,708 hip fractures in the Norwegian Hip Fracture Register from January 2014 to December 2018 were linked with data in the Norwegian Patient Registry. Hospitals treating hip fractures were characterized according to their hip fracture care. Waiting time (hours from admission to start of surgery), surgery within regular working hours, and surgery on the day of or on the day after admission, i.e. ‘expedited surgery’ were estimated.

Results

Mean waiting time was 22.6 hours (SD 20.7); 36,652 patients (97.2%) waited less than three days (< 72 hours), and 27,527 of the patients (73%) were operated within regular working hours (08:00 to 16:00). Expedited surgery was given to 31,675 of patients (84%), and of these, 19,985 (53%) were treated during regular working hours. Patients classified as American Society of Anesthesiologists (ASA) classes 4 and 5 were more likely to have surgery within regular working hours (odds ratio (OR) 1.59; p < 0.001), and less likely to receive expedited surgery than ASA 1 patients (OR 0.29; p < 0.001). Low-volume hospitals treated a larger proportion of patients during regular working hours than high volume hospitals (OR 1.26; p < 0.001). High-volume hospitals had less expedited surgery and significantly longer waiting times than low and intermediate-low volume hospitals. Higher ASA classes and Charlson Comorbidity Index increased waiting time. Patients not receiving expedited surgery had higher 30-day and one-year mortality rates (OR 1.19; p < 0.001) and OR 1.13; p < 0.001), respectively.

Conclusion

There is inequality in waiting time for hip fracture treatment in Norway. Variations in waiting time from admission to hip fracture surgery depended on both patient and hospital factors. Not receiving expedited surgery was associated with increased 30-day and one-year mortality rates.

Cite this article: Bone Jt Open 2021;2(9):710–720.

How do multimorbidity and lifestyle factors impact the perceived health of adults with intellectual disabilities?

BACKGROUND

Adults with intellectual disability (ID) have poorer physical and perceived health than the general population. Knowledge of perceived health predictors is both limited and important for guiding the development of preventive actions. The aims of this study were to investigate (1) the associations between perceived health and demographics, degree of ID, physical health conditions, and weight and physical activity level and (2) lifestyle factors and multimorbidity as predictors for perceived health adjusted for age, gender, and level of ID.

METHOD

The North Health in Intellectual Disability study is a community based cross-sectional survey. The POMONA-15 health indicators were used. Univariate and multivariate logistic regression analyses with poor versus good health as the dependent variable were applied.

RESULTS

The sample included 214 adults with a mean age 36.1 (SD 13.8) years; 56% were men, and 27% reported perceiving their health as poor. In univariate analyses, there were significant associations between poor health ratings and female gender, lower motor function, number of physical health conditions and several indicators of levels of physical activity. In the final adjusted model, female gender [odds ratio (OR) 2.4, P < 0.05], level of ID (OR 0.65, P < 0.05), numbers of physical health conditions (OR 1.6, P < 0.001) and lower motor function (OR 1.5 P < 0.05) were significant explanatory variables for poor perceived health, with a tendency to independently impact failure to achieve 30 min of physical activity daily (OR 2.0, P = 0.07).

CONCLUSION

Adults with ID with female gender, reduced motor function and more physical health conditions are at increased risk of lower perceived health and should be given attention in health promoting interventions. A lack of physical activity tends to negatively influence perceived health.

Hip fracture treatment in Norway: deviation from evidence-based treatment guidelines: data from the Norwegian Hip Fracture Register, 2014 to 2018

Aims

The aim of this study was to describe variation in hip fracture treatment in Norway expressed as adherence to international and national evidence-based treatment guidelines, to study factors influencing deviation from guidelines, and to analyze consequences of non-adherence.

Methods

International and national guidelines were identified and treatment recommendations extracted. All 43 hospitals routinely treating hip fractures in Norway were characterized. From the Norwegian Hip Fracture Register (NHFR), hip fracture patients aged > 65 years and operated in the period January 2014 to December 2018 for fractures with conclusive treatment guidelines were included (n = 29,613: femoral neck fractures (n = 21,325), stable trochanteric fractures (n = 5,546), inter- and subtrochanteric fractures (n = 2,742)). Adherence to treatment recommendations and a composite indicator of best practice were analyzed. Patient survival and reoperations were evaluated for each recommendation.

Results

Median age of the patients was 84 (IQR 77 to 89) years and 69% (20,427/29,613) were women. Overall, 79% (23,390/29,613) were treated within 48 hours, and 80% (23,635/29,613) by a surgeon with more than three years' experience. Adherence to guidelines varied substantially but was markedly better in 2018 than in 2014. Having a dedicated hip fracture unit (OR 1.06, 95%CI 1.01 to 1.11) and a hospital hip fracture programme (OR 1.16, 95% CI 1.06 to 1.27) increased the probability of treatment according to best practice. Surgery after 48 hours increased one-year mortality significantly (OR 1.13, 95% CI 1.05 to 1.22; p = 0.001). Alternative treatment to arthroplasty for displaced femoral neck fractures (FNFs) increased mortality after 30 days (OR 1.29, 95% CI 1.03 to 1.62)) and one year (OR 1.45, 95% CI 1.22 to 1.72), and also increased the number of reoperations (OR 4.61, 95% CI 3.73 to 5.71). An uncemented stem increased the risk of reoperation significantly (OR 1.23, 95% CI 1.02 to 1.48; p = 0.030).

Conclusion

Our study demonstrates a substantial variation between hospitals in adherence to evidence-based guidelines for treatment of hip fractures in Norway. Non-adherence can be ascribed to in-hospital factors. Poor adherence has significant negative consequences for patients in the form of increased mortality rates at 30 and 365 days post-treatment and in reoperation rates.Cite this article: Bone Joint Open 2020;1-10:644-653.

Limb girdle muscular dystrophy type 2I: No correlation between clinical severity, histopathology and glycosylated α-dystroglycan levels in patients homozygous for common FKRP mutation

Limb girdle muscular dystrophy type 2I (LGMD2I) is a progressive disorder caused by mutations in the FuKutin-Related Protein gene (FKRP). LGMD2I displays clinical heterogeneity with onset of severe symptoms in early childhood to mild calf and thigh hypertrophy in the second or third decade. Patients homozygous for the common FKRP mutation c.826C>A (p.Leu276Ile) show phenotypes within the milder end of the clinical spectrum. However, this group also manifests substantial clinical variability. FKRP deficiency causes hypoglycosylation of α-dystroglycan; a component of the dystrophin associated glycoprotein complex. α-Dystroglycan hypoglycosylation is associated with loss of interaction with laminin α2, which in turn results in laminin α2 depletion. Here, we have attempted to clarify if the clinical variability seen in patients homozygous for c.826C>A is related to alterations in muscle fibre pathology, α-DG glycosylation levels, levels of laminin α2 as well as the capacity of α-DG to bind to laminin. We have assessed vastus lateralis muscle biopsies from 25 LGMD2I patients harbouring the c.826C>A/c.826C>A genotype by histological examination, immunohistochemistry and immunoblotting. No clear correlation was found between clinical severity, as determined by self-reported walking function, and the above features, suggesting that more complex molecular processes are contributing to the progression of disease.

Carotid intima-media thickness progression and risk of vascular events in people with diabetes: results from the PROG-IMT collaboration

OBJECTIVE

Carotid intima-media thickness (CIMT) is a marker of subclinical organ damage and predicts cardiovascular disease (CVD) events in the general population. It has also been associated with vascular risk in people with diabetes. However, the association of CIMT change in repeated examinations with subsequent CVD events is uncertain, and its use as a surrogate end point in clinical trials is controversial. We aimed at determining the relation of CIMT change to CVD events in people with diabetes.

RESEARCH DESIGN AND METHODS

In a comprehensive meta-analysis of individual participant data, we collated data from 3,902 adults (age 33-92 years) with type 2 diabetes from 21 population-based cohorts. We calculated the hazard ratio (HR) per standard deviation (SD) difference in mean common carotid artery intima-media thickness (CCA-IMT) or in CCA-IMT progression, both calculated from two examinations on average 3.6 years apart, for each cohort, and combined the estimates with random-effects meta-analysis.

RESULTS

Average mean CCA-IMT ranged from 0.72 to 0.97 mm across cohorts in people with diabetes. The HR of CVD events was 1.22 (95% CI 1.12-1.33) per SD difference in mean CCA-IMT, after adjustment for age, sex, and cardiometabolic risk factors. Average mean CCA-IMT progression in people with diabetes ranged between -0.09 and 0.04 mm/year. The HR per SD difference in mean CCA-IMT progression was 0.99 (0.91-1.08).

CONCLUSIONS

Despite reproducing the association between CIMT level and vascular risk in subjects with diabetes, we did not find an association between CIMT change and vascular risk. These results do not support the use of CIMT progression as a surrogate end point in clinical trials in people with diabetes.

Prevalence, mutation spectrum and phenotypic variability in Norwegian patients with Limb Girdle Muscular Dystrophy 2I

Mutations in the FKRP (Fukutin Related Protein) gene produce a range of phenotypes including Limb Girdle Muscular Dystrophy Type 2I (LGMD2I). In order to investigate the prevalence, the mutation spectrum and possible genotype-phenotype correlation, we studied a cohort of Norwegian patients with LGMD2I, ascertained in a 4-year period. In this retrospective study of genetically tested patients, we identified 88 patients from 69 families, who were either homozygous or compound heterozygous for FKRP mutations. This gives a minimum prevalence of 1/54,000 and a corresponding carrier frequency of 1/116 in the Norwegian population. Seven different FKRP mutations, including three novel changes, were detected. Seventy-six patients were homozygous for the common c.826C>A mutation. These patients had later disease onset than patients who were compound heterozygous - 14.0 vs. 6.1 years. We detected substantial variability in disease severity among homozygous patients.

Individual progression of carotid intima media thickness as a surrogate for vascular risk (PROG-IMT): Rationale and design of a meta-analysis project

Carotid intima media thickness (IMT) progression is increasingly used as a surrogate for vascular risk. This use is supported by data from a few clinical trials investigating statins, but established criteria of surrogacy are only partially fulfilled. To provide a valid basis for the use of IMT progression as a study end point, we are performing a 3-step meta-analysis project based on individual participant data. Objectives of the 3 successive stages are to investigate (1) whether IMT progression prospectively predicts myocardial infarction, stroke, or death in population-based samples; (2) whether it does so in prevalent disease cohorts; and (3) whether interventions affecting IMT progression predict a therapeutic effect on clinical end points. Recruitment strategies, inclusion criteria, and estimates of the expected numbers of eligible studies are presented along with a detailed analysis plan.

Relation of common carotid artery lumen diameter to general arterial dilating diathesis and abdominal aortic aneurysms: the Tromsø Study

In a cross-sectional, population-based study in Tromsø, Norway, the authors investigated correlations between lumen diameter in the right common carotid artery (CCA) and the diameters of the femoral artery and abdominal aorta and whether CCA lumen diameter was a risk factor for abdominal aortic aneurysm (AAA). Ultrasonography was performed in 6,400 men and women aged 25-84 years during 1994-1995. An AAA was considered present if the aortic diameter at the level of renal arteries was greater than or equal to 35 mm, the infrarenal aortic diameter was greater than or equal to 5 mm larger than the diameter of the level of renal arteries, or a localized dilation of the aorta was present. CCA lumen diameter was positively correlated with abdominal aortic diameter (r = 0.3, P < 0.01) and femoral artery diameter (r = 0.2, P < 0.01). In a multivariable adjusted model, CCA lumen diameter was a significant predictor of AAA in both men and women (for the fifth quintile vs. the third, odds ratios were 1.9 (95% confidence interval: 1.2, 2.9) and 4.1 (95% confidence interval: 1.5, 10.8), respectively). Thus, CCA lumen diameter was positively correlated with femoral and abdominal aortic artery diameter and was an independent risk factor for AAA.

Lack of significant association between intima-media thickness in the carotid artery and serum TSH level. The Tromsø Study

BACKGROUND

Increased arterial wall intima-media thickness (IMT) is an early feature of atherosclerosis and has been reported to be altered in patients with thyroid dysfunction. The present study was performed to examine the relation between carotid artery intima-media thickness and possible variations in thyroid function in normal subjects using serum TSH as a surrogate index of thyroid function.

DESIGN

A total of 2034 subjects (974 males) were studied, 1856 or whom were non-users of thyroxine. The subjects not taking thyroxine were classified into three groups, those with a low serum TSH (0.48 mIU/L (2.5 percentile, those with serum TSH from 0.48 to 4.16 mIU/L, and those with high serum TSH of >4.16 mIU/L (97.5 percentile). Carotid ultrasound was performed in each all 2034 subjects to determine IMT.

RESULTS

Among those not taking thyroxine, subjects in the low serum TSH group had a higher mean IMT as compared to those in the normal and high serum TSH groups but the differences were not significant when adjusted for gender, age, smoking status, body mass index, systolic blood pressure and serum cholesterol (0.88 +/- 0.15 mm, 0.84 +/- 0.16 mm, and 0.84 +/- 0.24 mm respectively). Subjects taking thyroxine had significantly higher IMT than those not taking thyroxine (0.89 + 0.20 mm versus 0.84 + 0.17 mm, p<0.01).

CONCLUSIONS

No significant relationship between carotid IMT and serum TSH levels was observed in normal, non thyroxine taking, subjects. Carotid IMT was increased in subjects taking thyroxine. Whether the increase in carotid IMT is due to thyroxine ingestion or underlying thyroid disease cannot be answered from the study.

Carotid Atherosclerosis Is a Stronger Predictor of Myocardial Infarction in Women Than in Men

Background and Purpose— Ultrasound of carotid arteries provides measures of intima media thickness (IMT) and plaque, both widely used as surrogate measures of cardiovascular disease. Although IMT and plaques are highly intercorrelated, the relationship between carotid plaque and IMT and cardiovascular disease has been conflicting. In this prospective, population-based study, we measured carotid IMT, total plaque area, and plaque echogenicity as predictors for first-ever myocardial infarction (MI).

Methods— IMT, total plaque area, and plaque echogenicity were measured in 6226 men and women aged 25 to 84 years with no previous MI. The subjects were followed for 6 years and incident MI was registered.

Results— During follow-up, MI occurred in 6.6% of men and 3.0% of women. The adjusted relative risk (RR; 95% CI) between the highest plaque area tertile versus no plaque was 1.56 (1.04 to 2.36) in men and 3.95 (2.16 to 7.19) in women. In women, there was a significant trend toward a higher MI risk with more echolucent plaque. The adjusted RR (95% CI) in the highest versus lowest IMT quartile was 1.73 (0.98 to 3.06) in men and 2.86 (1.07 to 7.65) in women. When we excluded bulb IMT from analyses, IMT did not predict MI in either sex.

Conclusions— In a general population, carotid plaque area was a stronger predictor of first-ever MI than was IMT. Carotid atherosclerosis was a stronger risk factor for MI in women than in men. In women, the risk of MI increased with plaque echolucency.

[Can we rely on electronic reporting of laboratory results?]

BACKGROUND

Electronic result reporting from two laboratories to physicians in primary health care through electronic data interchange (EDI) has been used as a supplement to the printed reports. The aim of the study was to see if the quality of the electronic reporting could be improved so that the printed reporting could be cut out without any loss of data.

MATERIAL AND METHODS

Staff members in 20 selected offices were interviewed and error messages on file in the computer systems were studied.

RESULTS

During a period of four months, the laboratories sent 10,740 electronic messages to the selected offices. Error messages arose from 71 of these messages (0.7%). 49 of the errors were discovered and corrected by the staff, but 22 errors were not noticed, and the result reports were lost.

INTERPRETATION

If electronic result reporting should become the only reporting routine, it would be necessary to change several routines both in the laboratories and in the physician's offices. Patients must be identified by using official identifiers. The physicians must control in the computer system that all requested results are received, and the programs used for controlling the messages before they are entered into the electronic patient journal, must be improved.

[Prostate-specific antigen. A new biological serum marker for prostatic adenocarcinoma]

Prostate-specific antigen (PSA) was measured by polyclonal radioimmunoassay in 45 untreated patients with prostatic cancer and 14 patients with benign prostatic hyperplasia. Prostatic acid phosphatase (PAP) was determined in 35 patients with prostatic cancer and 14 patients with benign hyperplasia. Serum PSA was raised in 42 patients with cancer of the prostate, but only 14 of 35 patients showed increased serum levels of PAP. Half the patients with benign prostate hyperplasia had PSA greater than 4 micrograms/l and one third had PSA greater than 10 micrograms/l. PAP was slightly elevated in two patients with benign prostatic hyperplasia. Serum PSA increased with the clinical stage of prostatic cancer. However, preoperative levels of PSA were not sufficiently reliable to predict the final pathological stage for each individual patient. After radical prostatectomy for cancer confined to the prostate, serum PSA fell to an undetectable level.

Induction of cytosolic clofibroyl-CoA hydrolase activity in liver of rats treated with clofibrate

Among subcellular fractions of liver homogenates of rats, the clofibroyl-CoA hydrolase activity is found mainly in the cytosolic fraction. It is here shown that the subcellular distribution of clofibroyl-CoA hydrolase appears to be different from the distribution of palmitoyl-CoA hydrolase activity. Thus, in contrast to the case with palmitoyl-CoA, no hydrolysis of clofibroyl-CoA was catalysed by the microsomal fraction. Furthermore, the hydrolysis of palmitoyl-CoA and clofibroyl-CoA in the cytosolic fraction seemed to be catalyzed by two different enzymes. Rats treated with clofibrate (0.3%, w/w) showed a significant increased clofibroyl-CoA hydrolase activity where the cytosolic hydrolase was increased 3.5-fold. Clofibrate administration also elevated the specific clofibroyl-CoA hydrolase activity by factors of 1.7 and 1.5 in the mitochondrial and the light-mitochondrial fractions, respectively. Thus, it is possible that clofibroyl-CoA hydrolase has also a multiorganelle localization.

Separation and measurement of clofibroyl coenzyme A and clofibric acid in rat liver after clofibrate adminstration by reversed-phase high-performance liquid chromatography with photodiode array detection

A method to identify and quantitate clofibric acid and clofibroyl coenzyme A (CoA) products in rat liver was developed using reversed-phase high-performance liquid chromatography. The system was developed with baseline separation of clofibroyl-CoA from clofibric acid using isocratic elution, with a mobile phase consisting of 52% methanol and 28 mM potassium phosphate buffer (pH 4.2). With this high methanol concentration, the large amount of UV-absorbing materials present in the liver extracts were eluted earlier than the investigated compounds. Clofibroyl-CoA has a characteristic absorbance spectrum with distinct peaks at 260 and 230 nm, while clofibric acid showed only a distinct peak at 230 nm. Using an on-line photodiode array detector, the spectra could be recorded during analysis without interrupting the flow of the mobile phase. This spectral analysis identification possibilities and evaluation of the purity of the chromatographic peaks. In a perchloric extract of rat liver, the recovery of clofibric acid and clofibroyl-CoA added to the liver extract ranged from 70 to 80%. A linear relationship was observed between clofibric acid and clofibroyl-CoA concentration and the area of their peaks in the chromatogram. The detection limit of the method was lower than 5 pmol for both compounds when the absorbance was recorded at 230 nm. The method could be used without modification for the estimation of clofibroyl-CoA and clofibric acid in biological extracts.

Cerebrospinal fluid enzymes in neurological diseases

The activities of adenylate kinase, creatine kinase and lactate dehydrogenase were measured in cerebrospinal fluid and serum from 127 patients admitted to the Department of Neurology. All cerebrospinal fluid samples with hemoglobin greater than 1 mg/l were excluded. Upper reference limits for the enzyme determinations were established, using samples from patients without objective criteria of organic involvement of the nervous system. High enzyme activities did not correlate to any particular group of diseases and were also found in patients without organic brain diseases. We conclude that determination of the three enzymes in cerebrospinal fluid is of limited value in the diagnosis of neurological diseases.

Changes in fatty acid composition of myelin cerebrosides after treatment of the developing rat with methylmercury chloride and diethylmercury

Suckling rats were exposed to methylmercury chloride or diethylmercury in order to induce chronic sublethal intoxication during the period of active myelination. Doses of 5 mg Hg/kg body weight were injected every second day from 5-25 days of age. The rats were killed at 27-28 days of age, and the brains contained about 1 microgram Hg/g wet weight. No changes in brain weight, myelin content of proteins or phospholipids were found, whereas the cholesterol and galactolipid levels were slightly reduced. The most significant change observed was a decrease in the ratio between alpha-hydroxy fatty acid and the nonsubstituted fatty acid in the myelin cerebrosides. The biochemical changes were less pronounced in the animals given diethylmercury than in animals receiving methylmercury.