Molecular identification of 13 new enterovirus types, EV79-88, EV97, and EV100-101, members of the species Human Enterovirus B

Paired PBMCs and plasma samples from 34 HIV-infected patients were studied to verify the relationship between coreceptor use based on genotyping of V3 region of HIV-1 envelope gp120 and biological phenotype with virus isolation and subsequent correlation to clinical characteristics. The “11/25” rule, geno2pheno and PSSM were compared. All SI patients were HIV-1 subtype B (p = 0.04) and had a lower CD4 count than NSI patients (p = 0.01), while no differences were observed in mean HIV-RNA _log (p = 0.6). SI phenotype was not associated with AIDS-defining events (p = 0.1) or with concurrent antiretroviral therapy (p = 0.4). With geno2pheno, which shows the highest sensibility (83%), an X4 or X4/R5 genotype in PBMC DNA was also associated to B-subtype and lower CD4 count (p = 0.01) compared to R5 isolates. Based on plasma RNA sequences, the predicted coreceptor usage agreed with PBMC DNA in 79% of cases with the “11/25” rule, 82% with geno2pheno, and 82% with PSSM. A X4 virus in plasma (but not in PBMCs) was significantly associated with HAART in all three methods (p = 0.01 for “11/25” rule, p = 0.01 for geno2pheno and p = 0.03 for PSSM). Due to viral mixtures and/or difficulties in genotype interpretation, current V3 sequence-based methods cannot accurately predict HIV-1 coreceptor use.     

Use-dependent behavioral and neurochemical asymmetry in MPTP mice

Folic acid is believed to play a role in protection from oxidant stress. Low levels of folic acid had been found in serum from patients with Alzheimer disease (AD). Folate concentration was evaluated in sera from 136 patients with cortical dementia [AD, n = 108; frontotemporal dementia (FTD), n = 28], 57 patients with subcortical dementia [Lewy body disease (LBD), n = 9; corticobasal degeneration (CBD), n = 5; progressive supranuclear palsy (PSP), n = 6; Parkinson disease with dementia (PD-Dem), n = 37], and 76 nondemented, healthy age-matched people. Serum folic acid levels were decreased in patients with AD and FTD as compared with either controls or patients with subcortical dementia (3.60 ± 2.22 and 5.37 ± 2.92 μg/L versus 6.87 ± 3.50 μg/L, respectively; P < 0.01). A tendency towards decreased folate concentration was found in LBD and CBD, but not to a significant extent. The highest proportion of folate-deficient patients was found in CBD, FTD and AD (respectively, 60, 48.2 and 46.3% versus 7.9% in controls; P < 0.001). Folate deficiency characterizes FTD as well as AD. These differences observed among different clinical dementing syndromes may be related to neocortical damage.     

A metabolic link between S-adenosylhomocysteine and polyunsaturated fatty acid metabolism in Alzheimer's disease

There is evidence that vascular risk factors contribute to the pathology of Alzheimer's disease. Increased concentrations of circulating homocysteine are associated with vascular risk factors and Alzheimer's disease but the mechanisms involved are unclear. Homocysteine inhibits the hydrolysis of S-adenosylhomocysteine (SAH) which is a product inhibitor of S-adenosylmethionine (SAM) dependent methyltransferase reactions. It has been shown previously that SAH inhibits phosphatidylethanolamine N-methyltransferase (PEMT) in the liver. The activity of PEMT in the liver plays an important role in the methylation of phosphatidylethanolamine (PE) to phosphatidylcholine (PC) and the delivery of essential polyunsaturated fatty acids (PUFAs) to peripheral tissues. In the present study, the plasma concentrations of SAH, SAM and homocysteine and the erythrocyte composition of phosphatidylcholine (PC), phosphatidylethanolamine (PE) and their respective polyunsaturated fatty acid concentrations were determined in 26 patients with Alzheimer's disease and compared to those in 29 healthy control subjects. There was a significant increase in the plasma concentrations of SAH (p < 0.001) and homocysteine (p < 0.001) and a significant increase in the plasma concentrations of SAM (p < 0.001) in the Alzheimer's patients. A significant positive correlation was found between the plasma concentrations of SAH and homocysteine (r = 0.738, p < 0.001). There was a negative correlation between the plasma concentrations of homocysteine and the ratio of SAM/SAH (r = −0.637, p < 0.01). There was a significant decrease in the erythrocyte content of PC (p < 0.001) and an increase in the erythrocyte content of PE (p < 0.001) in the Alzheimer's patients. Plasma SAH concentrations were negatively related to erythrocyte PC concentrations (r = −0.286, p < 0.01) and positively related to erythrocyte PE concentrations (r = 0.429, p < 0.001). The erythrocyte PC from Alzheimer's patients had a significant depletion of docosahexaenoic acid (DHA) (p < 0.001) while there was no significant difference in the DHA content of erythrocyte PE. There was a significant negative correlation between plasma SAH and the DHA composition of erythrocyte PC (r = −0.271, p < 0.001). This data may reflect the inhibition of hepatic PEMT activity by SAH in Alzheimer's disease. The decreased mobilization of DHA from the liver into plasma and peripheral tissues may increases the risk of atherosclerosis and stroke leading to chronic cerebral hypoperfusion. The evidence suggests that a metabolic link between the increased production of SAH and phospholipid metabolism may contribute to cerebrovascular and neurodegenerative changes in Alzheimer's disease.     

Temperament, health-related behaviors, and autonomic cardiac regulation: the cardiovascular risk in young Finns study

Temperament, as indicated by Cloninger's psychobiological model predicts coronary heart disease risk, but its association with autonomic cardiac regulation, a potential mediating mechanism, is unclear. We examined the associations between temperament traits and autonomic cardiac regulation in a resting situation in 798 women and 580 men derived from a population-based sample. After adjustment for age and sex, harm avoidance was associated with lower level of high-frequency (HF) variation, root mean square successive differences (RMSSDs), the percentage of successive R–R intervals >50 ms (pNN50) and higher heart rate (HR) (all p ≤ 0.005), suggesting that harm avoidance is related to low parasympathetic activity. Additional adjustments for behavioral factors attenuated these associations more than the adjustment for biological risk factors. Novelty seeking was associated with higher RMSSD (p = 0.007) and pNN50 (p = 0.012) and lower heart rate (p < 0.001). With adjustment for behavioral risk factors, the associations with RMSSD (p = 0.136) and pNN50 (p = 0.236) attenuated to the null, but adjustment for biological risk factors had little effect. Reward dependence and persistence were unrelated to indices of cardiac regulation.     

Pineal gland calcification, lumbar intervertebral disc degeneration and abdominal aorta calcifying atherosclerosis correlate in low back pain subjects: A cross-sectional observational CT study

The goal of this cross-sectional observational study was to assess the possible impact of pineal gland calcification upon the intervertebral disc degeneration and abdominal aorta atherosclerosis in subjects with low back pain, and to investigate the course of these processes with aging. The study was carried out on 81 (66 women and 15 men) subjects: younger than 45 years (group X, n = 22), 45–65 years of age (group Y, n = 45), and older than 65 years (group Z, n = 14). In addition to clinical data, computed tomography (CT) scan of the brain as well as X-ray and CT examination of the lumbar spine were recorded in this study. The degree of disc degeneration and calcification rates of aortic wall and pineal gland were independently determined by two radiologists. Both ratio of calcified pineal gland and density of pineal calcification increased progressively with aging. Also, both the degree of aortic wall calcification and disc degeneration score increased with advancing age. On CT scan, a positive correlation between degree of aortic wall calcification and disc degeneration score was found (r = 0.306, p < 0.01). Importantly, there was a positive association between calcification of the pineal gland and degenerative disc disease in X-ray or CT study (r = 0.378 and r = 0.295, p < 0.005 and p < 0.01, respectively), as well as between abdominal aorta atherosclerosis and pineal calcification (r = 0.634, p < 0.001). Our findings suggest that there is a significant interaction between pineal gland calcification and lumbar intervertebral disc degeneration and also abdominal aorta atherosclerosis. However, further studies with a larger subject cohorts are needed.     

Oxidation, glycoxidation, lipoxidation, nitration, and responses to oxidative stress in the cerebral cortex in Creutzfeldt-Jakob disease

Gel electrophoresis and Western blotting of frontal cortex homogenates have been carried out in sporadic Creutzfeldt–Jakob disease (CJD) cases and age-matched controls to gain understanding of the expression of glycation-end products (AGEs). N-Carboxymethyl-lysine (CML) and N-carboxyethyl-lysine (CEL) were used as markers of glycoxidation; 4-hydroxynonenal (4-HNE) and malondialdehyde-lysine (MDAL) as markers of lipoxidation; and nitrotyrosine (N-tyr) and neuronal, endothelial and inducible nitric oxide synthase (nNOS, eNos and iNos) as markers of protein nitration and as sources of NO production, respectively. Age receptor (RAGE) and Cu/Zn superoxide dismutase (SOD1) and Mn superoxide dismutase (SOD2) expression levels were also examined. The results showed a significant increase in the expression levels of AGE (p < 0.05), CEL (p < 0.001), RAGE (p < 0.05), HNE-modified proteins (p < 0.01), nNOS, iNOS and eNOS (p < 0.01 and p < 0.05, respectively), N-tyr (p < 0.05), and SOD1 (p < 0.05) and SOD2 (p < 0.05). No relationship was observed between PrP genotype, PrP type, PrP burden, and expression levels of oxidative stress markers. The present findings demonstrate oxidative, glycoxidative, lipoxidative and nitrative protein damage, accompanied by increased oxidative responses, in the cerebral cortex in sporadic CJD. These results provide support for the concept that oxidative stress may have important implications in the pathogenesis of prion diseases.     

Genetic study evaluating LDLR polymorphisms and Alzheimer's disease

We genotyped SNPs rs11668477, rs12983082, rs11669576, rs2738444, rs5925 and rs1433099 in 405 Finnish AD cases and 463 controls and conducted a single allele and genotypic distribution comparison and estimated the haplotype frequencies between cases and controls and evaluated the level of biomarkers in haplotype carriers. We observed that T allele of rs2738444 was overrepresented in AD women with p = 0.014 (Bonferroni corrected p = 0.252). A specific haplotype block consisting of SNPs rs11669576, rs2738444 and rs5925 was identified and in women the haplotype GTT was overrepresented in AD cases when compared to controls with p = 0.008. We measured CSF Aβ₄₂, tau and phosphorylated tau (ptau) levels in a subgroup of cases and controls and found that some genotypes were associated with increased levels of tau and ptau or a decreased Aβ₄₂ level in women. The specific risk haplotype GTT was associated with an increased level of tau and ptau in both men and women. Our findings suggest that LDLR gene may be associated with AD risk and its CSF biomarkers, especially in women.     

Intact coupling of M1 receptors and preserved M2 and M4 receptors in the cortex in progressive supranuclear palsy: contrast with other dementias

Progressive supranuclear palsy (PSP) is a neurodegenerative disease characterised clinically by motor and cognitive symptoms. Cholinergic dysfunction is thought to be responsible for much of the cognitive symptomatology. To date, however, cholinergic replacement therapies have been ineffective. We used receptor specific radioligand autoradiography to measure M1, M2, and M4 receptor density, and the functional status of the principal cortical subtype, M1, in the frontal cortex in post-mortem brain tissue of PSP patients (n = 14). Results were compared to normal controls (n = 17) and patients with dementia with Lewy bodies (DLB, n = 12) and Alzheimer's disease (AD, n = 15). In PSP there were no changes in M1, M2, or M4 muscarinic receptor densities or M1 coupling. DLB cases showed a non-significant increase in M1 receptors. In AD there was a reduction in M1 receptors and coupling in most frontal cortical areas which reached significance, compared to DLB, for M1 receptors in the cingulate (p < 0.05). We conclude from this first systematic study of cortical muscarinic receptors in PSP that functioning cortical muscarinic receptors are preserved. A further, larger trial of cholinergic therapy, such as an M1 agonist, may be warranted.     

Intranasal 17beta-estradiol treatment and Vitamin B12, folate and homocysteine in menopause

Objective: This study assessed the effect of intranasal administration of 17β-estradiol (Aerodiol^®) on plasma levels of homocysteine, Vitamin B12 and folate in postmenopausal women.

Methods: In all, 26 symptomatic postmenopausal women who had undergone hysterectomy and oophorectomy at least 12 months previously participated in this 6-month randomized prospective clinical study. Menopause was determined by serum FSH level >30 μIU/ml and serum estradiol concentration <30 pg/ml. Intranasal 17β-estradiol treatment was given once daily at a standard daily dose of 300 μg to 16 women, and 10 did not receive any treatment.

Results: In the group receiving intranasal 17β-estradiol, mean (±S.D.) plasma homocysteine level decreased significantly from pre-treatment values (from 16.68 ± 4.33 to 14.15 ± 1.18 nmol/ml, p = 0.029) and the mean folate level increased (from 4.11 ± 0.80 to 5.64 ± 1.87 ng/ml, p = 0.012). Vitamin B12 levels showed a tendency towards increasing. In the treated group, significant negative correlations were observed between homocysteine and folate values (r = −0.586, p = 0.017) and between homocysteine and Vitamin B12 values (r = −0.672, p = 0.004). No significant changes were observed in the untreated group.

Conclusion: The reduction in plasma homocysteine levels observed after 6 months’ treatment with intranasal 17β-estradiol may reflect an alteration in folate and Vitamin B12 homeostasis.     

Cardiac and autonomic responses to change in posture or vitamin C supplementation in sickle cell anemia subjects

Autonomic function following change in posture with or without vitamin C supplementation was studied in ten (10) sickle cell anemia (SCA) and twelve (12) non-sickle cell anemia (NSCA) subjects. Arterial blood pressure and electrocardiographic measurements were taken in the supine position on a couch 80 cm high and immediately on assumption of the upright position. Vitamin C was then administered orally (300 mg/day for 6 weeks). At the end of the period, blood pressure and ECG measurements were again made in the supine position and in response to change in posture.

Change in posture significantly decreased QRS amplitude, QRS duration, PR interval, RR interval and MABP but increased HR and rate pressure product (RPP) in both groups of subjects. The HR and RPP responses were significantly higher in NSCA than in SCA subjects (p < 0.001, respectively). Vitamin C caused greater reductions in QRS duration (p < 0.01), PR duration p < 0.001) in the NSCA subjects than in SCA subjects. It caused, however, greater reduction in RR duration (p < 0.001) and MABP in SCA subjects than in NSCA subjects. It also caused significantly greater increases in HR and RPP (p < 0.001, respectively) in the SCA subjects than in NSCA subjects. After vitamin C supplementation, change in posture decreased RR interval (p < 0.001), QT interval (p < 0.01) and MABP (p < 0.05) but increased RPP (p < 0.01) in NSCA subjects. In SCA subjects, there was a fall in RR interval (p < 0.001) and MABP (p < 0.01), but elevated RPP (p < 0.001). Changes (Δ) in MABP, HR and RPP were similar between NSCA and SCA subjects. In conclusion, these findings indicate a blunted cardiovascular autonomic response to change in posture in sickle cell anemia subjects. Chronic, oral, low-dose vitamin C supplementation equilibrates this response with those of non-sickle cell anemia subjects.     

Effects of tibolone on body composition in postmenopausal women: a 1-year follow up study

Objective: We investigated the effects of 1-year tibolone treatment on body weight, body composition and indices of android obesity in postmenopausal women.

Methods: Forty-four postmenopausal women participated in this open-label controlled study; mean age was 51.8 ± 2.21 years and all women were menopausal for 3.8 ± 1.40 years. Twenty-two of them started taking 2.5 mg tibolone (TIB) daily for 1 year, whereas the remaining 22 served as age-matched controls. All subjects underwent a structured interview, physical examination, body composition measurements performed by dual-energy X-ray absorptiometry (DXA) — Hologic QDR 4500 A, as well as bioelectrical body impedance analysis (BI) — Tanita TBF-215, Japan.

Results: The TIB group did not significantly increase their weight (+0.4 kg), while the non-treated controls increased their mean weight by 1.4 kg (p = 0.046). In the TIB group, DXA showed a non-significant body fat decrease by a mean of 0.5 kg and a non-significant lean mass increase by 0.8 kg, while in the control group, fat mass increased by 1.7 kg (p = 0.032) and lean mass did not change. BI revealed that the TIB group had lost some fat (≈0.6 kg, n.s.) and put some free-fat mass (≈1.0 kg, p = 0.048) without changes in total body water. The control group put on some fat (≈1.1 kg, p = 0.042) and lost some body water (≈0.4 kg, n.s.).

Conclusion: Results from both methods of measuring body composition show a similar trend: a decrease in fat mass and an increase in lean mass in TIB treated subjects. From the body composition perspective, tibolone may be regarded as a preferential alternative to conventional hormonal therapy (HT) in postmenopausal women.     

Age-related changes in the incidence of pineal gland calcification in Turkey: A prospective multicenter CT study

The goal of this cross-sectional observational study was to determine the incidence of pineal gland calcification (PGC), to investigate the interaction of PGC and aging, and to compare the incidence of PGC among the populations living in Turkey. In a prospective study the rate of PGC on CT scans of 1376 individuals in six referral centers from different regions of Turkey was investigated, with emphasis on effects of climatological parameters and aging on PGC. It was found that the incidence of PGC increased rapidly after first decade and the increase remains gradual thereafter, higher in males than in females for all age groups. There was a significant difference for incidence and degree of PGC between different clinics and between both sexes (p < 0.001). In addition, there was a significant difference for the degree of PGC between the clinics in low altitude group and those in high altitude group (p < 0.001 for each). Logistic regression analysis revealed that age, sex, altitude and intensity of sunlight exposure significantly affected the risk of PGC (odds ratios (OR) 1.335, 95% confidence intervals (CI) 1.261–1.414, p < 0.001; OR 1.900, 95% CI 1.486–2.428, p < 0.001; OR 0.715, 95% CI 0.517–0.990, p < 0.05; OR 0.997, 95% CI 0.994–0.999, p < 0.01, respectively). Furthermore, by multiple linear regression analysis, high altitude and increased intensity of sunlight exposure were found to affect the degree of PGC (β = 0.003, p < 0.001). It is concluded that there is a close relationship between PGC and the aforementioned parameters, supporting a link between the development of PGC and these. This study provides some reference data for new clinical studies on the putative role of pineal gland in future.     

Correlation of estrogen receptor beta gene polymorphisms with spinal bone mineral density in peri- and post-menopausal Greek women

Estrogens play a significant role in bone physiology. Their action is mainly exerted through their receptors. Estrogen receptor alpha (ER) plays a major role in bone homeostasis and there is evidence suggesting that estrogen receptor beta (ERβ) has also an effect on BMD.

We investigated the possible effect of two ERβ gene polymorphisms on spinal bone mineral density (BMD) and metabolic bone markers in Greek women.

Spine BMD as well as biochemical bone markers were measured in 147 healthy peri- and post-menopausal women [mean age (S.D.) 54 (7.9) years]. Genotyping was performed for two restriction fragment length polymorphisms (RFLPs) of ERβ gene, RsaI in exon 5 and AluI in exon 8. For each polymorphism studied the cohort was divided into two groups: the “wild-type” group (RR and AA, respectively) and the “carrier” group including subjects with at least one allele with the restriction site (Rr&rr and Aa&aa, respectively).

The distribution of RsaI genotypes was RR: 91.2% (n = 134), Rr: 8.2% (n = 12), and rr: 0.6% (n = 1) and of AluI genotypes AA: 36.7% (n = 54), Aa: 57.2% (n = 84), and aa: 6.1% (n = 9). No linkage disequilibrium was found between the two polymorphic sites studied. Spine BMD did not differ significantly in the two groups of either polymorphism, after adjusting for age, weight, height, and years since menopause [mean BMD (S.D.) for RR 0.841 (0.17) g/cm² versus Rr&rr 0.798 (0.13) g/cm², p = 0.25, and mean BMD (S.D.) for AA 0.828 (0.16) g/cm² versus Aa&aa 0.848 (0.17) g/cm², p = 0.32]. No significant differences were noted in metabolic bone markers except for a marginal difference of RR versus Rr/rr in urinary hydroxyproline/creatinine ratio [median (IQR) 3.88 (6.04) μmol/mmol in RR versus 8.2 (4.32) μmol/mmol in Rr/rr, p = 0.05]. Furthermore, no interaction between the two polymorphisms on BMD was found.

In conclusion, in a Greek female post-menopausal population, the two ERβ gene polymorphisms were not associated with BMD, or metabolic bone markers.     

Adequate antipsychotic treatment normalizes serum nerve growth factor concentrations in schizophrenia with and without cannabis or additional substance abuse

Neurotrophins such as nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF) are important for the development and maintenance of neuron function. Neurodevelopment is thought to be impaired in schizophrenia, and vulnerable schizophrenic brains may be more sensitive to toxic influences. Thus, cannabis as a neurotoxin (and other substances) may be more harmful to schizophrenic brains than to non-schizophrenic brains, when used chronically. In a previous study we demonstrated an earlier disease onset and significantly higher serum NGF concentrations in drug-naïve schizophrenic patients with previous long-term cannabis abuse than in schizophrenics without cannabis abuse or cannabis abusers without schizophrenia. We therefore investigated whether this difference is still observed after treatment. Serum NGF measured in 114 treated schizophrenic patients (schizophrenia alone, n = 66; schizophrenia plus cannabis abuse, n = 42; schizophrenia plus multiple substance abuse, n = 6) no longer differed significantly among those groups and from the control groups (healthy controls, n = 51; cannabis controls, n = 24; multiple substance controls, n = 6). These results were confirmed by an additional prospective study in 28 patients suffering from schizophrenia (S) or schizophrenia with cannabis abuse (SC). Previously elevated serum NGF levels in the drug-naïve state, also differing between the groups (S: 83.44 ± 265.25 pg/ml; SC: 246.89 ± 310.24 pg/ml, S versus SC: p = 0.03) dropped to 10.72 ± 14.13 pg/ml (S) and 34.19 ± 38.96 pg/ml (SC) (S versus SC, p > 0.05), respectively, after adequate antipsychotic treatment. We thus conclude that antipsychotic treatment leads to recovery of neural integrity, as indicated by renormalized NGF values.     

Localized delivery of nitric oxide from hydrogels inhibits neointima formation in a rat carotid balloon injury model

Using novel nitric oxide (NO)-generating polymeric hydrogels that can be rapidly photopolymerized in situ, we can deliver NO locally at the site of vascular injury. Depending on material design, these poly(ethylene glycol) (PEG)-based hydrogels can generate NO for up to 50 d. This study demonstrates the ability of nitric oxide-generating hydrogels (PEG-Cys-NO) to influence key components of the restenosis cascade both in vitro and in vivo. PEG-Cys-NO hydrogels inhibited smooth muscle cell proliferation, increased endothelial cell proliferation, and inhibited platelet adhesion in vitro. Moreover, in vivo, PEG-Cys-NO hydrogels inhibited intimal thickening in a rat carotid balloon injury model. The perivascular application of NO-generating polymers post-injury reduced neointima formation at 14 d by approximately 80% compared to controls (intimal area/medial area (I/M): PEG-Cys-NO = 0.20 ± 0.17, control = 0.84 ± 0.19, p < 0.00002; intimal thickness: PEG-Cys-NO = 12 ± 10 μm, control = 60 ± 18 μm, p < 0.00002). Treatment with the PEG-Cys-NO hydrogels caused a significant decrease in the per cent of proliferating cell nuclear antigen positive medial cells (29 ± 5%) at 4 d as compared to treatment with the control hydrogels (51 ± 1%, p < 0.02). Additionally, vessel re-endothelialization at 14 d was slightly enhanced in the presence of the NO-generating hydrogels. These data indicate that localized delivery of NO from these hydrogels can significantly inhibit neointima formation in a rat carotid balloon injury model and suggest that these materials may be useful in preventing restenosis.     

Reduced hippocampal glutamate in Alzheimer disease

Altered neurometabolic profiles have been detected in Alzheimer disease (AD) using ¹H magnetic resonance spectroscopy (MRS), but no definitive biomarker of mild cognitive impairment (MCI) or AD has been established. This study used MRS to compare hippocampal metabolite levels between normal elderly controls (NEC) and subjects with MCI and AD. Short echo-time (TE = 46 ms) ¹H spectra were acquired at 4 T from the right hippocampus of 23 subjects with AD, 12 subjects with MCI and 15 NEC. Absolute metabolite levels and metabolite ratios were compared between groups using a multivariate analysis of covariance (covariates: age, sex) followed by post hoc Tukey's test (p < 0.05 significant). Subjects with AD had decreased glutamate (Glu) as well as decreased Glu/creatine (Cr), Glu/myo-inositol (mI), Glu/N-acetylaspartate (NAA), and NAA/Cr ratios compared to NEC. Subjects with AD also had decreased Glu/mI ratio compared to MCI. There were no differences between subjects with MCI and NEC. Therefore, in addition to NAA/Cr, decreased hippocampal Glu may be an indicator of AD.     

A high n-6 polyunsaturated fatty acid diet reduces muscarinic M2/M4 receptor binding in the rat brain

The aim of this study was to examine the influence of different fat diets on muscarinic acetylcholine receptor binding. Nineteen male Sprague–Dawley rats were divided into four groups and fed a diet of either high saturated fat, n-6 polyunsaturated fatty acid (PUFA), n-3 PUFA or low fat (control) for 8 weeks. Using quantitative autoradiography, [³H]pirenzepine binding to muscarinic M1/M4 receptors and [³H]AF-DX384 binding to M2/M4 receptors were measured throughout the brain in all four groups. The main findings were that compared to the low fat control group, M2/M4 receptor binding was significantly reduced in the dorsolateral, dorsomedial and ventromedial parts of the caudate putamen (61–64%, p < 0.05), anterior cingulate cortex (59%, p < 0.01), dentate gyrus and CA1–3 fields of the hippocampus (32–43%, p < 0.01) of rats on a high n-6 PUFA diet; however, no differences in M1/M4 receptor binding densities between the four groups were observed. These results suggest that a diet high in n-6 PUFA, but not of n-3 PUFAs or saturated fat, may selectively alter M2/M4 receptor-mediated signal transduction in the rat brain.     

Back extensor muscle oxygenation and fatigability in healthy subjects and low back pain patients during dynamic back extension exertion

The purpose of this study was to assess if chronic low back pain patients have impaired paraspinal muscle O₂ turnover and endurance capacity as compared to healthy control subjects during dynamic exercise. Middle-aged healthy male subjects (n = 12, control) and male patients with chronic low back pain (n = 17, CLBP) participated in the study. L4–L5 level paraspinal muscle fatigue was objectively assessed during earlier validated 90 s dynamic back endurance test (spectral EMG, MPF_slope). Also EMG amplitude (EMG_amplitude) and initial MPF (MPF_initial) were assessed from the initial 5 s of the endurance contraction. Simultaneously near infrared spectroscopy (NIRS) was used for quantitative measurement of local L4–L5 paraspinal muscle O₂ consumption. Subcutaneous tissue thickness (ATT) was measured from the EMG and NIRS recording sites. The results indicated that control and CLBP groups were compatible as regarding anthropometric variables, paraspinal muscle activation levels (EMG_amplitude), initial MPF (MPF_initial) and ATT. When the ATT was used as a covariate in the ANOVA analysis, CLBP group did not show significantly greater paraspinal muscle fatigability (right MPF_slope – 12.2 ± 10.7%/min, left right MPF_slope – 12.6 ± 13.3%/min) or O₂ consumption (right NIRS_slope – 52.8 ± 79.6 μM/l/s) as compared to healthy controls (right MPF_slope – 11.9 ± 7.6%/min, left MPF_slope – 12.7 ± 8.6%/min, right NIRS_slope – 53.7 ± 95.2 μM/l/s). As a conclusion, these CLBP male patients did not show any impaired rate of paraspinal muscle oxygen consumption or excessive paraspinal muscle fatigability during dynamic exercise as compared with healthy controls. Subcutaneous tissue thickness has a strong influence on the NIRS and EMG amplitude measurements and, if unchecked, it could result in the false interpretation of the results.     

Cell density alters matrix accumulation in two distinct fractions and the mechanical integrity of alginate-chondrocyte constructs

Chondrocyte density in articular cartilage is known to change with the development and growth of the tissue and may play an important role in the formation of a functional extracellular matrix (ECM). The objective of this study was to determine how initial chondrocyte density in an alginate hydrogel affects the matrix composition, its distribution between the cell-associated (CM) and further removed matrix (FRM) fractions, and the tensile mechanical properties of the developing engineered cartilage. Alginate constructs containing primary bovine chondrocytes at densities of 0, 4, 16, and 64 million cells/ml were fabricated and cultured for 1 or 2 weeks, at which time structural, biochemical, and mechanical properties were analyzed. Both matrix content and distribution varied with the initial cell density. Increasing cell density resulted in an increasing content of collagen and sulfated-glycosaminoglycan (GAG) and an increasing proportion of these molecules localized in the CM. While the equilibrium tensile modulus of cell-free alginate did not change with time in culture, the constructs with highest cell density were 116% stiffer than cell-free controls after 2 weeks of culture. The equilibrium tensile modulus was positively correlated with total collagen (r² = 0.47, p < 0.001) and GAG content (r² = 0.68, p < 0.001), and these relationships were enhanced when analyzing only those matrix molecules in the CM fraction (r² = 0.60 and 0.72 for collagen and GAG, respectively, each p < 0.001). Overall, the results of this study indicate that initial cell density has a considerable effect on the developing composition, structure, and function of alginate–chondrocyte constructs.