Serotonin gene polymorphisms in patients with panic disorder

INTRODUCTION

The objective is to investigate the possible association between four serotonin gene polymorphisms (T102C, A-1438G, 5-HTTLPR and VNTR-5HTT) and panic disorder (PD).

PATIENTS AND METHOD

92 PD outpatients (DSM-IV criteria) and 174 healthy volunteers from Asturias (control group) were included. Polymorphisms were determined after polymerase chain reaction amplification followed by digestion with restriction enzymes and electrophoresis on an agarose gel.

RESULTS

Both 5-HT2A polymorphisms are in complete linkage disequilibrium in our population. No statistically significant differences in genotype frequencies of serotonin gene polymorphisms (T102C, A-1438G, 5HTTLPR and VNTR-5HTT) were found between patients and control subjects. Allele frequencies did not differ between both groups. No differences were found according to gender.

CONCLUSIONS

The polymorphisms studied were not associated with PD in our population. However, larger patient samples are necessary to confirm or reject these findings.

The Pro279Leu variant in the transcription factor MEF2A is associated with myocardial infarction

BACKGROUND

A myocyte enhancer factor 2A (MEF2A) mutation that segregated with coronary artery disease/myocardial infarction (CAD/MI) in a large family has recently been described. Missense mutations in sporadic coronary artery disease patients were also reported. These data suggest that mutations in exons 7 and 11 of MEF2A cause CAD/MI, though the association was refuted by another study.

OBJECTIVE

To analyse the genetic variation of exons 7 and 11 in a large cohort of Spanish CAD/MI patients and controls.

METHODS AND RESULTS

A rare polymorphism, P279L, was detected both in patients and controls. Carriers of the 279Leu allele had a threefold risk of suffering CAD/MI compared with controls (p = 0.009; odds ratio = 3.06 (95% confidence interval, 1.17 to 8.06)). In the controls the allele was found only in those under 50 years of age. Exon 11 showed a high degree of heterogeneity caused by a polyglutamine (CAG)n polymorphism, but no significant differences in genotype or allelic frequencies were found.

CONCLUSIONS

The 279Leu allele appears to be a genetic risk factor for CAD/MI in the population studied. This effect could be the result of a reduced transcriptional activity on MEF2A with 279Leu.

Negative evidences in association between apolipoprotein E polymorphism and panic disorder

The aim is to investigate the association between apolipoprotein E (ApoE) and panic disorder (PD). Genotyping 92 PD patients [Diagnostic Statistic Manual IV (DSM IV) criteria] and 174 controls no differences were found between both groups. Variation in the ApoE-gene was not associated with the development of PD.

[Pharmacogenetics of angiotensin system in non diabetic nephropathy]

BACKGROUND

Genetic variability could contribute to the response to pharmacological treatment in patients with nephropathy. In albuminuric diabetic patients the renoprotective effect of angiotensin I-converting enzyme (ACE) inhibition should be lower among homozygotes for the deletion allele (DD) compared to II-homozygotes.

METHODS

A total of 71 non-diabetic chronic nephropathy patients were treated with losartan (n = 37) or amlodipine (n = 34). Blood pressure and proteinuria were determined before and after the treatment, and changes in the mean values were statistically compared. Patients were genotyped for the ACE-I/D, angiotensin I receptor type 1 (AGTR1)-1166 A/C, and angiotensinogen (AGT)-M235T polymorphims, and the reduction of blood pressure and proteinuria between the different genotypes were compared.

RESULTS

The reduction in systolic or diastolic blood pressure was not found to be different between the ACE-I/D or AGT-M/T genotypes in patients treated with losartan or amlodipine. In patients treated with losartan, we found a significantly higher reduction of diastolic blood pressure in AGTR1-AA patients compared to AC patients (p = 0,0024). We did not find differences in proteinuria-reduction between the different genotypes in patients treated with losartan or amlodipine.

CONCLUSIONS

Our data show that the effects of losartan and amlodipine on the absolute mean reduction of blood pressure and proteinuria in non-diabetic nephropathy patients are similar between the different ACE or AGT genotypes. Although based on a small number of patients, the AGTR1-AA genotype was associated with a significantly higher reduction in diastolic blood pressure among losartan-treated patients. Additional studies are necessary to refute or confirm this association.

Relative contribution of colostrum from Maedi-Visna virus (MVV) infected ewes to MVV-seroprevalence in lambs

Maedi-visna virus (MVV) seroprevalence associated with consumption of colostrum from seropositive ewes was investigated in 276 housed lambs from birth to 300 days-old. At birth, lambs were allocated to five experimental groups according to the maternal MVV-serological status, source and mode of feeding colostrum (bovine or ovine and bottle fed or suckled from the dam) and type of horizontal MVV-exposure (raised with the dam or separately with other lambs). The risk of being seropositive at 300 days-old was associated with feeding ovine colostrum from seropositive ewes and increased with intake of bottle-fed ovine colostrum and was higher in lambs separated from their dams and raised with other experimental lambs compared to lambs raised with their dams. Approximately 75-87% of ELISA-positive results in lambs that had ovine colostrum was attributable to colostrum itself. However, approximately only 16% of naturally raised and 29-61% of bottle-fed ovine colostrum lambs were ELISA-positive as a result feeding ovine colostrum. These results confirm that ovine colostrum from seropositive ewes can be a major source of MVV but its overall contribution to seroprevalence in natural conditions is relatively low, and shows that horizontal MVV transmission can be an important source of infection in new-born lambs.

Differential effect of fetal, neonatal and treatment variables on neurodevelopment in infants with congenital hypothyroidism

OBJECTIVES

To identify the influence of fetal, neonatal and treatment variables on neurodevelopment in children with congenital hypothyroidism.

METHODS

A multiple regression analysis was performed in the neurodevelopmental scores of 26 children with CH who were assessed at 3, 6, 12 and 18 months for postural control, fine eye-hand coordination and language. The independent variables were: duration of fetal hypothyroidism, initial biochemical severity, days at starting treatment, initial dose, and efficiency of treatment.

RESULTS

Postural control was predicted by duration of fetal hypothyroidism and language by the biochemical severity of the disease at birth. Fine eye-hand coordination was not predicted by any variable.

CONCLUSION

This pattern of influences suggests that fetal and neonatal hypothyroidism have different effects on brain maturation sites during the first 2 years of life and that some subtle neurocognitive deficits are probably unavoidable.

[Influence of different pharmacological agents in the ex vivo proliferation of mesothelial cells obtained from the peritoneal effluent of patients treated with peritoneal dialysis]

Mesothelial cells (MC) are the first peritoneal membrane barrier in contact with dialysate. The aim of this study was to analyze the in vitro capacity of different pharmacological agents to modify the ex vivo proliferation of MC obtained from the peritoneal effluent of patients treated with peritoneal dialysis (PD).

MATERIAL AND METHODS

Thirty cultures of MC taken from nocturnal peritoneal effluent were performed. After identification, MC are subcultured in 24 multi-well plates, adding the different exogenous agents. Proliferative capacity and cell morphology were estimated on day 16th of culture. The agents evaluated were insulin, IGF-1, tamoxifen, labetalol, carvedilol, enalapril and losartan.

RESULTS

Insulin shows a dose-dependent effect on MC growth, with a limit that is stimulated by the addition of fetal bovine serum (FBS). Concentrations higher than 100 micrograms/ml, are not associated with further growth, even with cell damage. In contrast, the wide range of IGF-1 dose used did not affect to MC proliferation. Tamoxifen causes negative effects on MC growth just a very high doses, not resembling doses in clinical practice. Labetalol does not modify MC proliferation used under therapeutic calculated range. However, concentrations higher than 40 micrograms/ml showed a negative influence on growth, behaving as lethal doses that over 100 micrograms/ml. The addition of FBS attenuates this effect. These effects were very similar to that caused by carvedilol addition. Enalapril and losartan act as antiproliferative agents for MC. This effect is potentiated with angiotensin II, reaching lethal concentrations increasing the dose. In conclusion, mesothelial cell growth ex vivo taken from nocturnal peritoneal effluent on PD patients is an useful tool to explore the effects of any pharmacological agent on the biology of the cell of the peritoneum. The agents used had any influence in the proliferation capacity of mesothelial cells.

Influence of anticalcineurinic therapy in plasma homocysteine levels of renal transplant recipients: a prospective study

Hyperhomocysteinemia is an independent factor for cardiovascular disease. Renal function and folate level are important determinants of total plasma homocysteine levels. The influence of anticalcineurin drugs on homocysteine levels is controversial. The aims of the study were: (1) to analyze changes in homocysteine levels after the first year of 73 renal transplants and (2) to determine the influence of immunosuppressive anticalcineurin drug therapy on fasting homocysteine concentrations. We examined homocysteine, serum creatinine, folate, and vitamin B12 concentrations immediately after transplant, at 6 months, and after 12 months from renal transplant. Also, MTHFRC677T polymorphism was investigated. Tacrolimus was administered in 28 patients and cyclosporine in 45. Homocysteine levels decreased from 28.41+/-13.71 micromol/L to 18.59+/-8.31 micromol/L after 6 months and to 17.13+/-7.06 micromol/L after 1 year. No relationship was found between homocysteine and folate levels. When anticalcineurin drugs were considered, the homocysteine levels in patients treated with tacrolimus was lower than that in patients treated with cyclosporine at month 6 after transplant (16+/-7.4 micromol/L vs 20.1+/-8.5 micromol/L, P=.03) and after 1 year (15+/-7.6 micromol/L vs 18.4+/-6.4 micromol/L, P=.04). Serum creatinine levels followed the same evolution: they were lower in patients treated with tacrolimus at 6 months (1.35+/-0.36 mg/dL vs 1.57+/-0.45 mg/dL, P=.03) and to a lesser extent at 1 year after renal transplant (1.38+/-0.35 mg/dL vs 1.54+/-0.45 mg/dL, P=.09). The homocysteine value closely related with serum creatinine in both groups. In conclusion, 1 year posttransplant, the homocysteine level was lower among patients treated with tacrolimus, the cohort that also showed the lower serum creatinine concentrations.

[Relative abundance of Amblyomma spp. (Acari: Ixodidae) in bovines (Bos taurus and B. indicus) from Costa Rica]

The research describe the big amount of ticks of the Amblyomma genus, found on bovines through monthly samplings carried out in ten farms in eight ecological zones (EZ) of Costa Rica. Ticks larger than 4 mm were picked up from the right side of the animals during the visit. The study compiled meteorological information for some farms located in the experiment, showing that the most fluctuant variable is rainfall. The most important Amblyomma species found was A. cajennense. Amblyomma nymphs were found only from January to May, which coincides with the lower humidity season in the rain seasonality area; as for it is expected only one generation per year. In the lab work Amblyomma nymphs are kept to measure the moulting season and the surviving time under controlled conditions, but no major differences were found between both sexes. The surviving periods show that it is not possible to do a grazing land handling, in order to control this genus species. Adults of the genus Amblyomma are present through all the year, not showing any specific preference for a season. The research divided the investigation areas in rain seasonability and not-seasonality systems. The highest amount of Amblyomma is found given in the rain seasonality system or of pacific influence. A. maculatum is present only in the EZ of Tropical Humid Forest transition to pre-mountainous. Likewise, Ixodes boliviensis is found in the EZ of low mountainous Very Humid Forest.

[Relative frequency of Boophilus microplus (Acari: Ixodidae) in bovines (Bos taurus and B. indicus) in 8 ecological zones of Costa Rica]

The research on the relative abundancy of Boophilus microplus took place in ten farms, distributed in eight ecological zones (EZ) and two rainfall systems of Costa Rica. Monthly visits were made to pick up ticks larger than 4 mm from the right side of the animals. The total number of ticks was increased by two and divided between the total of sampled bovines per farm. Farm visits were adjusted to animals bath to allow the recovery of the tick population. B. microplus was detected in all sampled farms throughout the year. Media comparison statistic analyses were made and no differences were found among EZ, farms and seasons. On the contrary, there were important statistical differences between rainfall systems. The rainfall system 1, that included rain seasonality, showed larger tick infestations (p = 0.03). An isothermal and low variability regarding relative humidity situations were present in some of the areas included in this research. Bath intensity was lower to other past studies. Even though no differences were found between production systems, it is important to emphasize that bath intensity was higher in european cattle farms, in comparison to others of the same EZ, but of crossbred. A tick manual removable system was recommended in dual-purpose and specialized dairy farms with no more than 30-35 animals, as an alternative feasible system that significantly reduced acaricide use.

[Sudden death in a normal heart. Idiopathic ventricular fibrillation. Review of the literature concerning one case]

Idiopathic ventricular fibrillation is that which is produced in the absence of structural cardiac disease and of other identifiable causes of ventricular fibrillation such as cardiotoxicity, electrolytical alterations or hereditary predisposition. The case of a healthy male, aged 37, who was asymptomatic until the day he was admitted to hospital where he showed numerous episodes of ventricular fibrillation without any previous triggering, is discussed. In the examination no cause was found to explain this, and an automatic defibrillator was implanted. The requirements for its diagnosis, risk stratification and the usefulness of the tests employed, as well as the treatments proposed are discussed.

Comparisons of hemodialysis and CAPD in patients over 65 years of age: a meta-analysis

This meta-analysis had the aim of studying the available studies on comparison between Hemodialysis and Peritoneal Dialysis in the elderly. The final objective was to reach, if possible, evidence for potential differences. In the case that no differences could be demonstrated, contribute to accept that HD and PD are similar techniques to be offered to elderly people requiring dialysis. The question formulated was this: Do we have adequately contrasted data on results for survival, hospitalization rate, quality of life and morbidity on hemodialysis and peritoneal dialysis in the elderly (more than 65 years old)? As data sources we selected eight papers that compared the general results of these two dialysis techniques. Different elements were considered in this selection because none reached the two first levels in the hierarchy of sources of evidence, and only two reached the third level--that of prospective studies; this is because an oral presentation of data has been included in a meta-analysis. Another four papers--uni- or multicenter retrospective studies compared the results obtained with PD and HD. The remaining two papers--reports from nationwide registries that compare of mortality rates, adjusted for co-morbid conditions and age, present specific results on groups of elderly patients. Three papers compare particular aspects of the two techniques, including nutritional status, psychiatric and psychosocial aspects and rehabilitation, in this case comparing PD with home hemodialysis patients. Finally, we have included the opinions of healthy elderly people on dialysis issues. This meta-analysis of these different studies suggests that the mortality and hospitalization rate of elderly people treated by PD is similar to that of similar people treated by HD. In consequence, we have no reasons to select either therapy on behalf of the patient. The nephrologist should consider and inform the patient and family about the relative advantages and disadvantages of both techniques and tailor dialysis technique choice to the specific individual to assure the best results. Local circumstances should also be considered.

Apolipoprotein E genotype and schizophrenia: further negative evidence

OBJECTIVE

To investigate the association between apolipoprotein E (ApoE) genotype and schizophrenia.

METHOD

We genotyped 106 schizophrenic out-patients [Diagnostic Statistic Manual IV (DSM-IV) criteria] and 250 healthy volunteers (hospital staff and blood donors) from Asturias (Northern Spain). The ApoE genotypes (epsilon2, epsilon3, epsilon4-alleles) were determined after polymerase chain reaction (PCR) amplification, followed by digestion with the restriction enzyme Cfol and electrophoresis on a 4% agarose gel.

RESULTS

No significant differences in ApoE-allele frequencies between patients and controls was found, although an increased 64-frequency was recorded in patients compared with controls [9.0% vs. 6.2%, P = 0.124; odds ratio (OR) = 1.49; 95% confidence interval (CI) = 0.82-2.70]. ApoE-genotype frequencies did not differ between both groups. The mean age of onset for schizophrenic patients that carried the epsilon4-allele was not significantly different from that of patients without this allele.

CONCLUSION

Variation in the ApoE gene was not associated with the development of schizophrenia in our population. ApoE-genotypes did not modify the age of onset of the disease.

A RAVE about opioid withdrawal

Control of trafficking of g protein-linked receptors is thought to be an important regulatory mechanism for receptor signaling. Finn and Whistler test the hypothesis that agonist-induced trafficking of opioid receptors regulates the development of tolerance and dependence. The results show that measures of tolerance and withdrawal to morphine are decreased under conditions where receptors are trafficked through the endocytic/recycling pathway.

Variation at the Angiotensin-converting enzyme and endothelial nitric oxide synthase genes is associated with the risk of esophageal varices among patients with alcoholic cirrhosis

Esophageal varices are a frequent complication among patients with liver cirrhosis. Nitric oxide and other vasoactive molecules regulate the vascular tone in both the liver microcirculation and the systemic and splanchnic circulation. Several genes that encode proteins involved in the maintenance of vascular tone, such as the endothelial-constitutive nitric oxide synthase (ecNOS), the angiotensinogen (AGT), the angiotensin-converting enzyme (ACE), and the angiotensin II receptor type 1 (AT1R) are polymorphic, and these polymorphisms have been associated with several cardiovascular diseases. Our aim was to define a possible role for DNA polymorphisms at these genes in the risk of developing esophageal varices among patients with alcoholic cirrhosis. We analyzed 145 male patients with liver cirrhosis. Patients and 200 healthy controls were genotyped by polymerase chain reaction for the ACE-I/D, the AGT-M235T, the AT1R-A1166C, and the ecNOS-4/5 (intron 4) polymorphisms. Ninety-five patients had varices and 50 did not show this complication. Carriers of the ACE-I allele (ID + II genotypes) were at a significantly higher frequency among patients with varices (p = 0.013). Patients without varices had a higher frequency of the ecNOS-4 allele compared with patients with varices (p = 0.026). ACE-I carriers + ecNOS-55 were at a significantly higher frequency (p = 0.0012; odds ratio = 3.19; 95% CI = 1.55-6.55) among patients with varices (51 of 95, 54%) compared with patients without (18 of 50, 36%). Allele and genotype frequencies for the AGT and AT1R polymorphisms did not differ between the two groups. The genotypes associated with an increased risk for varices have been linked to higher plasma levels of nitric oxide and reduced levels of ACE. These genotypes could have a vasodilatory effect in the systemic and splanchnic circulation, thus favoring the development of portocollaterals.

Early-onset Parkinson's disease associated with a new parkin mutation in a Spanish family

Mutations in the PARKIN gene are associated with early-onset (juvenile) Parkinson's disease. We analyzed the coding sequence of this gene (exons 1-12) in patients from a family with three affected siblings, born to first-degree consanguineous parents, with an onset before 23 years and foot dystonia as the initial clinical symptom. The three patients were alive without cognitive impairment at ages of 70, 69, and 65 years, showing a marked response to levodopa treatment. A 2 bp-deletion at exon 11 (1276-1277 del GA) was found. The three patients were homozygous for this frameshift mutation, which would introduce a Stop at codon 394. This is a new PARKIN-mutation that would produce a truncated protein, lacking exon 12 and most the 11th. This region includes the C-terminal ring-finger domain of parkin, essential for its function as a ubiquitin-protein ligase. Compared to patients from other families with truncating mutations, our patients had an earlier onset. In addition, the three patients had dystonia at onset. In conclusion, we described a new PARKIN truncating mutation associated with an early onset parkinsonism, and the presence of foot dystonia as the initial symptom.

Obesity, body fat distribution, and ambulatory blood pressure in children and adolescents

Obesity is a common disease with an ever-increasing prevalence and usually with late-onset consequences. If acquired during childhood, it tracks into adult life to some extent, and since the relationship between obesity and hypertension is well established in adults, obese children appear to be at particularly high risk of becoming hypertensive adults. In the authors' study, obese children seemed to have significantly higher casual and ambulatory blood pressure than nonobese children, except for nighttime diastolic blood pressure. The health effects of obesity may depend on the anatomic distribution of body fat, which in turn may be a better indicator of endocrinologic imbalance, environmental stress, or genetic factors than is fatness per se. Subjects with a higher waist-to-hip ratio or a larger waist, as an estimate of central obesity, tend to have higher blood pressure values even during childhood. Prevention of the onset of obesity in early life may be important to reducing the risk of coronary heart disease in later life.

Anorexia in end-stage renal disease: pathophysiology and treatment

Anorexia is a frequent complication of uraemic syndrome, which contributes to malnutrition in dialysis patients. Uraemic anorexia has been associated with many factors. This paper reviews the current knowledge about mechanisms responsible for uraemic anorexia, the treatments and new drugs used to control the loss of appetite. Traditionally, anorexia in dialysis patients has been considered as a sign of uraemic toxicity, therefore, two hypotheses have been proposed, the 'middle molecule' and 'peak-concentration' hypotheses, both of which are still unproved. Recently, our group proposed the tryptophan-serotonin hypothesis, which is based on a disorder in the amino acid profile acquired in the uraemic status. This is characterised by low concentrations of large neutral and branched chain amino acids (LNAA/BCAA) in the cerebrospinal fluid. This situation permits a high level of tryptophan transport across the blood-brain barrier, causing an increase in the synthesis of serotonin (responsible for appetite inhibition). There are two main treatment targets for anorexia in dialysis patients. The first is to decrease the free plasma tryptophan concentration and transport across the blood brain barrier to the cerebrospinal fluid, thus decreasing the intracerebral serotonin levels. Nutritional formulae enriched with LNAA and BCAA have this effect. Secondly, plasma levels of cytokines with cachectin effect (TNF-alpha), should be decreased. This also induces a decrease in LNAA and BCAA levels. In this group are megestrol acetate, anti-TNF-alpha antibodies, thalidomide, pentoxifyilline, n-3 fatty acids and possibly nandrolone decanoate. Additionally, other targets should be explored including antagonists of cholecystokinin (a potent anorexigen retained by renal failure), analogues of neuropeptide Y (the most potent orexigen), cannabinoids, cyproheptadine, hydrazine sulfate. In conclusion, uraemic anorexia is a complex complication associated with malnutrition, high morbidity and mortality. The pharmacological treatment should address key points in the pathogenesis of uraemic anorexia, reducing intra-cerebral concentration of serotonin with LNAA/BCAA oral diet formulae and the plasma levels of pro-inflammatory molecules. Others forms of treatment should also be explored.

Birth weight influences blood pressure values and variability in children and adolescents

The objective of the present study was to assess the relationships between birth weight and the values and variability of ambulatory blood pressure. Six hundred thirty healthy children (369 girls) age 4 to 18 years (mean, 9.9 years) born at term after a normotensive pregnancy were included. The subjects were divided into 5 groups according to birth weight. For each subject, a 24-hour ambulatory blood pressure monitoring was performed according to the protocol designed. Average and variability (estimated as the standard deviation) of ambulatory blood pressure and heart rate were calculated separately for 24-hour, daytime, and nighttime periods. When values were adjusted for gender, current age, weight, and height, children with the lowest birth weights had the highest ambulatory blood pressure values and variability, whereas no differences in heart rate were observed. Multiple regression analysis showed that although current weight was the strongest predictor for 24-hour systolic blood pressure (P<0.001), there was also an independent and significant inverse relationship for birth weight (P<0.002) after controlling for gender, current age, and height. Likewise, birth weight was independently and inversely correlated with 24-hour systolic blood pressure variability (P<0.03). In conclusion, children who had lower birth weights tended to have not only the highest blood pressure values but also the highest blood pressure variability, independent of the increases in ambulatory blood pressure values. Knowing that high blood pressure variability is at least partially independent of blood pressure values, the importance of this variability on further blood pressure rises and/or on vascular damage later in life needs to be assessed in future studies.

[The inflammatory process of cardiovascular disease: new markers]

For many years the classic model used for explaining the genesis of atheromatosis was that involving classic cardiovascular risk factors, caused either by a harmful life style or by hereditary alterations of the metabolism, principally dislipaemias. Recently we have learnt that, intimate molecular processes, as the inflammatory cytokine and cellular cascades, explain a great part of the vascular damage leading to the ischaemic episodes observed in the clinic. It can even be assessed, in general, the seric inflammation markers, as hypothetical tools for early diagnosis of vascular disease, are located on the physiopathological path between the classic risk factor (arterial hypertension, hypercholesterolaemia, obesity, diabetes) and the arterial lesion. This paper describes these inflammatory mechanisms, both from the viewpoint of basic science and from the viewpoint of its clinical role, and it also analyses the epidemiological value that these might have in the study of populations.

Lack of association between polymorphisms of the coagulation factor VII and myocardial infarction in middle-aged Spanish men

In order to determine the role of two polymorphisms in the factor VII gene (R353Q and intron 7 hypervariable region) in the susceptibility to develop early myocardial infarction, a total of 175 patients with acute myocardial infarction aged 50 years or less (mean age 41+/-7 years) and 200 controls (average age 42+/-6) without cardiovascular disease were genotyped for these polymorphisms. Gene and genotype frequencies did not differ between patients and controls. Although the 353-QQ genotype was at a higher frequency among controls (4%) compared to patients (1%), the difference did not reach statistical significance. Carriers of the H7-allele (intron 7 polymorphism) were at a slightly higher frequency among patients (51 vs. 43%; P=0.19; OR=1.36; 95% CI=1.09-1.70). Our data suggest a lack of association between both polymorphisms in the factor VII gene and early myocardial infarction in our population.

Association between the NOS3 (-786 T/C) and the ACE (I/D) DNA genotypes and early coronary artery disease

DNA polymorphisms at the endothelium constitutive nitric oxide synthase gene (NOS3) have been linked to the risk of developing coronary artery disease (CAD). In vitro, a polymorphism in the 5' region of the NOS3 gene (-786 T/C) influences promoter activity. This polymorphism has been associated with coronary spasms among Japanese. The genetic variation at the angiotensin-converting enzyme (ACE) is associated with plasma ACE activities and has also been linked with susceptibility to cardiovascular disease. Our objective was to determine if DNA polymorphisms in the NOS3 and ACE genes were associated with early CAD. We analyzed the -786 T/C polymorphism in the 5' flanking region and the 27-bp repeat polymorphism in NOS3 intron 4, as well as the ACE-I/D polymorphism. A total of 170 male smokers (CAD patients) younger than 50 years and 300 male smokers (healthy controls) were genotyped. Frequencies were compared by the chi(2) test, and odds ratios (ORs) and their 95% confidence intervals (CI) were also calculated. Only the -786 T/C polymorphism in the 5' flanking region of the NOS3 gene was significantly associated with early CAD in our population. The frequency of the CC genotype was significantly increased (P = 0.039) in patients compared to controls (OR = 1.67; 95% CI = 1.01, 2.72). We found a synergistic effect between the NOS3-CC and the ACE-DD genotypes in the risk of developing early CAD. The frequency of CC + DD was significantly increased among patients (P = 0.002). Thus, those with a NOS3-CC and an ACE-DD genotype would have a significantly increased risk of suffering an early episode of coronary artery disease (OR = 2.82; 95% CI = 1.40, 5.70). Although based on a limited number of patients, our work suggests that individuals who are NOS3-CC + ACE-DD are at a higher risk for early CAD, probably as a consequence of increased endothelial dysfunction.

The spectrum of circadian blood pressure changes in type I diabetic patients

BACKGROUND

The objective of the present study was to characterize the spectrum of circadian blood pressure changes in type I diabetes at different stages of nephropathy by using two monitorings in each patient in order to avoid intra-individual variability.

PATIENTS AND METHODS

A total of 80 type I diabetic subjects and the same number of age, sex and awake mean blood pressure (BP)-matched controls were included. According to urinary albumin excretion, there were 57 normoalbuminurics, 15 persistent microalbuminurics and eight proteinurics. Two 24 h ambulatory blood pressure monitorings were performed at the same urinary albumin excretion stage in absence of antihypertensive treatment for each diabetic subject and for their respective control. Blood pressure and heart rate averages during 24 h, awake, sleep, and day: night ratio were calculated.

RESULTS

Seven of the eight proteinuric subjects were hypertensives, whereas hypertension was absent in the normoalbuminuric and microalbuminuric groups. The intraindividual reproducibility in diabetics showed repeatability coefficients for the 24 h systolic and diastolic pressure of 33 and 42%, respectively. This reproducibility for the day: night ratio was generally worse, 57% for systolic and 59% for diastolic. A progressive increment in the mean ambulatory BP was observed across the three groups of diabetics and the differences in BP observed were most evident during the night-time period. Though no differences in the 24 h circadian pattern were present between the normoalbuminurics and their controls, nocturnal differences were observed, not only in microalbuminurics for systolic BP (P < 0.05), but also in proteinurics for both systolic BP (P < 0.01) as well as diastolic BP (P < 0.05). No differences were observed in heart rate among the diabetic groups. The non-dipping pattern in the two monitorings was observed in 80, 58, 18 and 10% of the proteinurics, microalbuminurics, normoalbuminurics and control groups, respectively.

CONCLUSIONS

Persistent abnormal circadian variability seems to be an early and frequent characteristic of type I diabetics with an increased urinary albumin excretion. Although present in some normalbuminuric subjects, the frequency of this abnormality increases as the incipient nephropathy progresses. By the time proteinuria is established, nearly all subjects present the abnormal pattern.

Genetic variation at the chemokine receptors CCR5/CCR2 in myocardial infarction

Our objective was to examine the association between myocardial infarction (MI) and two DNA-polymorphisms at the proinflammatory chemokine receptors CCR2 (I64V) and CCR5 (32 bp deletion, (Delta)ccr5), defining if these polymorphisms influence the age for the onset of MI. A total of 214 patients with an age at the first MI episode <55 years, 96 patients that suffered the first MI episode when older than 60 years, and 360 population controls were polymerase chain reaction genotyped for the CCR2-V64I and CCR5-Delta32/wt polymorphisms. Patients and controls were male from the same Caucasian population (Asturias, northern Spain). The frequency of the Deltaccr5 allele was significantly higher in controls compared to patients <55 years (P = 0.004), or in patients >60 years compared to patients <55 years (P = 0.002). Taking the patients >60 years as the reference group, non-carriers of the (Delta)ccr5-allele would have a three-fold higher risk of suffering an episode of MI at <55 years of age (OR = 3.06; 95% CI = 1.46-6.42). Gene and genotype frequencies for the CCR2 polymorphism did not differ between patients <55 years and controls or patients >60 years. Our data suggest that the variation at the CCR5 gene could modulate the age at the onset of MI. Patients carrying the (Delta)ccr5-allele would be protected against an early episode of MI. CCR5 and the CCR5-ligands are expressed by cells in the arteriosclerotic plaque. Thus, the protective role of (Delta)ccr5 could be a consequence of an attenuated inflammatory response, that would determine a slower progression of the arteriosclerotic lesion among (Delta)ccr5-carriers. Our work suggests that the pharmacological blockade of CCR5 could be a valuable therapy in the treatment of MI.

CCR5 (chemokine receptor-5) DNA-polymorphism influences the severity of rheumatoid arthritis

Chemokines are critical for the inflammatory process in autoimmune diseases such as rheumatoid arthritis (RA). The chemokine receptor-5 (CCR5) mediates chemotaxis by CC-chemokines and is expressed by lymphocytes with the Th1 phenotype and monocyte/macrophages. A 32 bp deletion in the CCR5 (CCR5-delta 32 allele) abolishes receptor expression in homozygotes, while CCR5-delta 32 carriers would express less receptor than wild-type homozygotes. This polymorphism is related to the resistance to HIV-1 infection and progression towards AIDS. We hypothesized that the CCR5-delta 32 allele may modulate the severity of disease in RA. A total of 160 RA-patients (71 and 89 with severe and non-severe phenotypes, respectively) and 500 healthy individuals from the same Caucasian population (Asturias, northern Spain) were genotyped. Carriers of the CCR5-delta 32 allele were at a significantly higher frequency (P = 0.012) in non-severe compared to severe patients (17% vs 4%). Our results suggest that the CCR5-delta 32 polymorphism is a genetic marker related to the severity of RA.

Variation in the LRP-associated protein gene (LRPAP1) is associated with late-onset Alzheimer disease

The LRP-associated protein is involved in the amount of mature LRP expressed on liver and brain. LRP is the main ApoE receptor and also binds alpha2-macroglobulin (alpha2M), a protein that associates with the beta-amyloid protein (betaA). By binding to alpha2M, LRP is responsible for the clearance of secreted betaA, thus preventing fibril formation. Genetic variation at the APOE, A2M, and LRP genes has been associated with the risk of developing late-onset Alzheimer disease (LOAD). We genotyped 373 patients, 300 controls, and 100 healthy elderly controls for a common DNA-polymorphism at the LRPAP1 gene (Insertion/Deletion, intron 5). Homozygotes for the rare Insertion (I) allele were at a significantly lower frequency in patients compared with controls (P = 0.002; OR = 0.29; 95% CI = 0.13, 0.68), and in patients compared with healthy elderly controls (P = 0.0002; OR = 0.18; 95% CI = 0.07, 0.46). No patient with an age at the onset below 75 years was II (0 of 214) compared with 8 in the group above 75 years (8 of 159) (P = 0.0044), suggesting that this genotype delays the onset of the disease. According to our data, the variation at the LRPAP1 gene is associated with the risk of developing LOAD. This is in agreement with the role of the LRPAP1 protein in the amyloidogenic pathway.

[Molecular changes in epidermoid carcinoma of the oropharynx]

In most of the studies about molecular alterations in squamous cell carcinomas of the head and neck there is not distinction between the different subsites of this area. The objective of this study is to describe the molecular alterations in squamous cell carcinomas of the oropharynx. Twenty-nine oropharyngeal carcinomas, with a minimum follow-up of 36 months, were studied. The molecular alterations analyzed were: the amplification of 11q13 region (in the 29 cases), and the MYC and ERBB1 oncogenes (in 22 cases); the integration of Human Papillomavirus (HPV) types 6b and 16 (in 22 cases); the loss of heterozygosity (LOH) of p53 and N-acetyltransferase-2 (NAT2) gene (in 12 and 13 informative cases, respectively); and the cellular DNA content (in 13 cases). The most frequent alterations found were the LOH at p53 (67%), and NAT2 (54%) locus, followed by 11q13 amplification (49%). ERBB1 amplification was found in 14% of the cases, and MYC amplification only in one (5%). Integration of the HPV was found in 23% of the cases. Nine (69%) of the 13 analyzed cases were aneuploid. The only alteration with a prognostic significance was 11q13 amplification that showed a tendency to be associated with a higher frequency of nodal metastases and tumor recurrence.

Synergistic effect between apolipoprotein E and angiotensinogen gene polymorphisms in the risk for early myocardial infarction

BACKGROUND

Several studies based on different populations worldwide have described an association between cardiovascular diseases and genetic variations in the apolipoprotein E (A:POE), angiotensinogen (A:GT), angiotensin receptor type 1 (A:T1R), and angiotensin-converting enzyme (A:CE) genes. In addition, there is growing evidence of an interaction between hypercholesterolemia and the renin-angiotensin system in the risk for hypertension and atherosclerosis.

METHODS

To determine whether the DNA polymorphisms in A:POE (epsilon2, epsilon3, and epsilon4 alleles), A:GT (M235T), A:T1R (1166 A:/C:), and ACE (I:/D:) are associated with early onset of myocardial infarction (MI), we genotyped 220 patients and 200 controls <55 years of age. Patients and controls were males from the same homogeneous Caucasian population. Data concerning hypertension, diabetes, and tobacco consumption were recorded. The lipid profiles of patients and controls were also determined.

RESULTS

APOE, ACE, AGT, and AT1R allele and genotype frequencies did not differ between patients and controls. None of these polymorphisms was related to the biochemical values in patients or controls. The frequency of individuals who were both APOE epsilon4 allele carriers and AGT-TT homozygotes was significantly higher in patients than in controls (11% vs 3.5%; P: = 0.0037). In patients, the frequency of epsilon4 carriers was significantly higher (P: <0.00001) in those who were AGT-TT (46%) than those who were AGT-MT/MM (14%). Mean cholesterol was significantly higher in AGT-TT + APOE epsilon34/44 patients than in the TM/MM + epsilon34/44 or TT + epsilon23/33 genotypes (P: = 0. 029).

CONCLUSIONS

Our data suggest a synergistic effect between the APOE and AGT polymorphisms and early MI. The increased risk could be mediated in part through higher cholesterol concentrations among individuals who are AGT-TT + APOE epsilon4 allele carriers.

Icodextrin effluent leads to a greater proliferation than glucose effluent of human mesothelial cells studied ex vivo

OBJECTIVE

To compare the effect of glucose (Glu) and icodextrin (Ico) dialysate on in vitro culture of mesothelial cells (MC) from peritoneal dialysis (PD) patients.

DESIGN

Prospective, controlled comparative study on the effects of two PD solutions.

SETTING

A tertiary-care public university hospital.

PATIENTS

Sixteen PD patients regularly using Glu dialysate were asked to collect an 8-hour dwell peritoneal effluent on 2 different days, with an interval shorter than 7 days. In the first collection, 2.27% Glu solution and in the last, 7.5% Ico solution was infused. Human MC were isolated from the nocturnal peritoneal effluent bags and grown ex vivo.

MAIN OUTCOME MEASURES

Mesothelial cell proliferative capacity ex vivo.

RESULTS

Mesothelial cells were present in all patient dialysates except that of a single patient's Glu dialysate. The number of MC drained was similar with both solutions. After the initial culture reached confluence, MC were identified in 14 and 12 patients receiving Ico and Glu, respectively. However, in 1 patient using Ico and in 2 using Glu, the MC count at this stage was so low that further subculture could not be performed. Cells from Ico-derived solutions exhibited a higher degree of proliferation than cells from Glu-derived solutions. The morphology of MC was also different. Cells from drained effluent were typical in 11 patients using Glu solution in contrast with 14 patients using Ico. At confluence, the percentages of typical appearance were 50% and 92.9% (p < 0.05) in Glu and Ico respectively.

CONCLUSIONS

Mesothelial cells taken from icodextrin effluent show a greater proliferation ex vivo than those taken from glucose effluent.

A DNA polymorphism at the alpha2-macroglobulin gene is associated with the severity of rheumatoid arthritis

OBJECTIVE

To determine if DNA polymorphisms at the alpha2-macroglobulin (alpha2m) and angiotensin converting enzyme (ACE) genes were associated with rheumatoid arthritis (RA).

METHODS

A total of 160 patients (71 with early active severe RA, 89 with non-severe RA) were genotyped (polymerase chain reaction) for the alpha2m (5 bp deletion/insertion) and ACE (I/D) polymorphisms. We also genotyped 500 healthy controls from the same Caucasian population (Asturias, Northern Spain).

RESULTS

Carriers of the alpha2m deletion allele were at a significantly higher frequency among patients with an early active severe form of the disease, compared to patients with non-severe RA (p = 0.037). The frequency of the alpha2m deletion allele was significantly higher in patients with severe compared to nonsevere RA (p = 0.017). In addition, the frequency of the deletion allele was significantly higher among patients with 5 or more episodes of acute exacerbation of disease activity per year (n = 39) compared to those with none (n = 46) (p = 0.002). Gene and genotype frequencies for the ACE-I/D polymorphism did not differ between those with early active severe and non-severe RA.

CONCLUSION

The genetic variation at alpha2m is associated with the severity of RA. Carriers of the alpha2m deletion allele would have increased risk of developing an early active severe form of the disease. Our data suggest that alpha2m could be a valuable target in the treatment of RA.

Obesity modifies the relationship between ambulatory blood pressure and natriuresis in children

BACKGROUND

The objective in the present study was to evaluate if obesity beginning in the first two decades of life influences the relationship between ambulatory blood pressure and urinary sodium excretion.

DESIGN AND METHODS

Eighty-five obese and 88 non-obese children aged 3-19 years were included in the study. For each subject, a 24h ambulatory blood pressure monitoring and a complete urine collection were simultaneously performed according to the protocols designed. The averages of ambulatory blood pressure and of the urinary excretion rates for sodium, potassium and creatinine were calculated separately for 24-h, awake and sleep periods as defined by a mini-diary.

RESULTS

Weight and sodium excretion are directly associated with systolic blood pressure; however, the relationship between blood pressure and sodium excretion seems to be modified in obese children as compared to controls. The interaction between sodium excretion and weight was negative indicating that the rate of change of systolic blood pressure by sodium unit is smaller for the obese than for the non-obese, even though at the same urinary sodium excretion level the obese children had higher ambulatory systolic blood pressure.

CONCLUSIONS

Obesity during the first two decades of life seems to restrict sodium excretion, leading to higher blood pressure values. The capacity to excrete sodium seems to be heterogeneous, the lowest capacity being at the highest blood pressure values. Subsets of the obese, those with the lowest ability to excrete sodium, may be further protected by low sodium intake in order to prevent a rise in blood pressure.

Genetic variation in the renin-angiotensin system and athletic performance

The D allele at the angiotensin-I-converting enzyme (ACE)-insertion/deletion polymorphism has been associated with an increased risk of developing several pathological processes, such as coronary heart disease and ventricular hypertrophy. Individuals with the DD genotype show a significantly increased left-ventricular mass in response to physical training, compared to the II genotype (which would be associated with the lowest plasma ACE levels) and the ID genotype. The II genotype has been linked to a greater anabolic response. In accordance with a role for ACE in the response to rigorous physical training, a higher frequency of the I allele has been reported to exist among elite rowers and high-altitude mountaineers. Sixty elite (professional) athletes (25 cyclists, 20 long-distance runners, and 15 handball players), and 400 healthy controls were genotyped for the DNA polymorphisms of the ACE, angiotensinogen (Ang) and angiotensin receptor type 1 (AT1) genes. Plasma ACE levels showed a strong correlation with the I/D genotype in our population. The I-allele occurred at a significantly higher frequency in athletes compared to controls (P = 0.0009). Gene and genotype frequencies for the Ang and AT1 polymorphisms did not differ between athletes and controls. Since the frequency of the ACE I allele was significantly increased among our elite athletes, we conclude that the ACE polymorphism represents a genetic factor that contributes to the development of an elite athlete.

Prevalence of dermographism in children

The prevalence of dermographism in our pediatric population was studied in 238 children of both sexes (128 boys and 110 girls) aged 2-14 years, randomly selected from a health care center. Skin reaction was evaluated after 5 min pressure (3,200 g/cm2) applied with a dermatographometer on a 5-cm length of dorsal skin. The reaction was considered positive when a wheal of more than 2 mm was observed. The prevalence of dermographism was found to be 24%, with a significant female predominance (33%) over males (16%). Forty-one percent of the children with dermographism reported exanthema in response to friction and pressure, which was compatible with symptomatic dermographism, compared with only 5% of those who yielded negative reactions. In order to assess the prevalence of dermographism in the atopic population, 100 patients in the 4-14 age range with respiratory disease (perennial allergic rhinitis and/or bronchial asthma) involving sensitization to aeroallergens (house dust mites and/or Alternaria) were studied. A positive response to the application of pressure (3,200 g/cm2) was observed in 47% of cases, this figure being significantly higher than in the general pediatric population.

Immunohistochemical localisation of rabbit haemorrhagic disease virus VP-60 antigen in early infection of young and adult rabbits

This study evaluated the time course distribution of rabbit haemorrhagic disease virus (RHDV) structural protein VP60 in tissues from experimentally infected rabbits from three different age groups. Viral VP60 antigen could not be detected in tissue samples from animals under four weeks, and only a few hepatocytes (0.01 to 0.2 per cent) were stained in the 6-week-old animals. A 6-week-old rabbit euthanised at 72 hpi showed VP60-labelling in hepatocytes and macrophages close to areas of inflammation. Viral VP60 antigen was detected as early as 12 hpi in a few hepatocytes (0.03 per cent) from adult animals. Within this age group, the extent of hepatocyte labelling considerably increased at 18 (3.0 per cent), 24 (25.5 per cent), 36 (50 per cent) and 48 (60 per cent) hpi. Extrahepatic viral VP60 antigen was also detected at 36 and 48 hpi in spleen macrophages and lymphocytes from adult rabbits. These findings support the hypothesis that the hepatocyte is the only cell type in the liver able to support RHDV replication almost immediately after viral infection.

Analysis of chromosome 6p in Spanish families with recessive polycystic kidney disease

Several previous reports have suggested that autosomal recessive polycystic kidney disease (ARPKD) is caused by mutations in a single gene (the PKDH1 gene). Linkage analysis showed a positive linkage for polymorphic markers at the short arm of chromosome 6 (6p) in all families. PKHD1 has not been cloned. Recombinants in the critical region would permit the narrowing of the 6p interval containing the PKHD1 gene, thus facilitating the final identification (cloning) of this gene. Our study included 30 Spanish families. Each family consisted of both parents and at least two children, with at least one diagnosed with ARPKD by clinical and pathological parameters. DNA was obtained and 6p microsatellite markers were used to establish haplotypes for each family. A positive linkage to chromosome 6p was found for all families. In 2 cases, recombinants in the region containing the PKHD1 gene were found. These families will help narrow the size of the 6p region, facilitating the efforts to position and clone the PKHD1 gene. In conclusion, our analysis of Spanish ARPKD families confirms the lack of linkage heterogeneity. This suggests that mutations at a single locus on chromosome 6p21.1-p12 are responsible for the broad clinical spectrum of variable phenotypes.

Angiotensin converting enzyme and endothelial nitric oxide synthase DNA polymorphisms and late onset Alzheimer's disease

OBJECTIVES

Several lines of evidence suggest that the endothelial constitutive nitric oxide synthase (ecNOS) and angiotensin converting enzyme (ACE) may have a role in Alzheimer's disease. ACE is widely expressed in the brain, and a DNA polymorphism at the ACE gene has been linked to the risk for late onset Alzheimer's disease. Nitric oxide (NO) production by microglial cells, astrocytes, and brain microvessels is enhanced in patients with Alzheimer's disease. There is a growing evidence that NO is involved in neuronal death in Alzheimer's disease, and the oxidative stress caused by NO in the brain could be a pathogenic mechanism in Alzheimer's disease. The objective was to determine if two DNA polymorphisms at the ecNOS and ACE genes that have been linked with different levels of enzyme expression, have some effect on the risk of developing late onset Alzheimer disease.

METHODS

A total of 400 healthy controls younger than 65 years and 350 patients with Alzheimer's disease (average age 72 years) were genotyped for the ACE and ecNOS polymorphisms. To define a possible role for these polymorphisms in longevity 117 healthy controls older than 85 years were also analysed. Genomic DNA was obtained and amplified by polymerase chain reaction, and genotypes were defined following a previously described procedure. Gene and genotype frequencies between patients and controls were compared statistically.

RESULTS

Gene and genotype frequencies for the ecNOS and ACE polymorphisms did not differ between both groups of healthy controls (<65 years and >85 years). EcNOS gene and genotype frequencies were similar between patients and controls. There was a slight but significantly increased frequency of the ACE-I allele among patients with Alzheimer's disease compared with controls (p=0.03; OR=1.28, 95%CI= 1.04;1.58).

CONCLUSIONS

The ACE-I allele was associated with a slightly increased risk of developing late onset Alzheimer's disease.

[Remediable glucocorticoid hyperaldosteronism: molecular diagnosis]

BACKGROUND

The first family diagnosed in Spain of glucocorticoid remediable aldosteronism (GRA) is reported.

SUBJECTS AND METHODS

We described the phenotype, biochemical values and genetic diagnosis of a GRA pedigree. DNA analysis was performed by using Southern-blot and polymerase chain reaction.

RESULTS

We reported a 14-year-old boy who presented with severe hypertension, and strong family history of early-onset hypertension. His suppressed plasmatic renin activity, family history and failure to respond to conventional antihypertensive therapy raised GRA as a potential etiology. The diagnosis was confirmed by genetic testing, in the index case and in one of family members, which demonstrated the chimeric gene duplication, which was a resultant of a crossing-over between the proximal portion of 11 beta-hydroxylase gen, CYP11B1, and the distal portion of aldosterone synthetase gene CYP11B2. Two other family members, who died, suffered hyporeninemic severe hypertension. The cause of death in one of them was hemorrhagic stroke. Amiloride, which blocks sodium transport in the distal nephron, plus hydroclorothiazide was an effective treatment option.

CONCLUSIONS

The role of molecular diagnosis techniques is essential for the rapid diagnosis of cases of arterial hypertension secondary to familial glucocorticoid remediable aldosteronism.

Current databases on biological variation: pros, cons and progress

A database with reliable information to derive definitive analytical quality specifications for a large number of clinical laboratory tests was prepared in this work. This was achieved by comparing and correlating descriptive data and relevant observations with the biological variation information, an approach that had not been used in the previous efforts of this type. The material compiled in the database was obtained from published articles referenced in BIOS, CURRENT CONTENTS, EMBASE and MEDLINE using "biological variation & laboratory medicine" as key words, as well as books and doctoral theses provided by their authors. The database covers 316 quantities and reviews 191 articles, fewer than 10 of which had to be rejected. The within- and between-subject coefficients of variation and the subsequent desirable quality specifications for precision, bias and total error for all the quantities accepted are presented. Sex-related stratification of results was justified for only four quantities and, in these cases, quality specifications were derived from the group with lower within-subject variation. For certain quantities, biological variation in pathological states was higher than in the healthy state. In these cases, quality specifications were derived only from the healthy population (most stringent). Several quantities (particularly hormones) have been treated in very few articles and the results found are highly discrepant. Therefore, professionals in laboratory medicine should be strongly encouraged to study the quantities for which results are discrepant, the 90 quantities described in only one paper and the numerous quantities that have not been the subject of study.

[Frequency of the APOE-4 allele in Alzheimer's disease and its variation with age in Asturias (Spain)]

BACKGROUND

Patients with late-onset Alzheimer's disease show a higher frequency of the APOE-4 than controls. The usefulness of the APOE genotyping in the diagnosis of the disease is controversial. Recently, an age dependent prevalence of APOE-4 in Alzheimer's disease has been described, with a maximum frequency for patients with an age at onset between 65 and 80 years. Additionally, the APOE-4 frequency in healthy controls is similar among the different age-groups, including healthy octogenarians. These data suggest that APOE-4 determines when and not who will develop the disease.

PATIENTS AND METHODS

The APOE genotype was defined following a previously described PCR-protocol. We analysed 120 patients with clinically defined probable Alzheimer's disease and 250 controls from the same Caucasian population (Austrias, Northern Spain).

RESULTS

We found a significantly higher frequency of the APOE-4 in patients, compared to controls (p = 0.00001). The prevalence of this allele was 65% among patients with an age at onset 66-70, falling to 36% and 18% in patients younger than 65 and older than 80 years, respectively. The average age (SD) at onset did not differ between the E-44 (69 years), E-34 (73 years) and E-33 (73 years). APOE-4 frequency was similar between the different age-groups of controls, including healthy octogenarians.

CONCLUSIONS

In Asturias, APOE genotyping can not be used for the presimptomatic diagnosis of Alzheimer's disease. However, individuals carrying this allele would have a higher probability of developing the disease at an age between 65 and 80 years if they are predisposed (genetically and/or environmentally) to the disease.