Upper airway muscle activity in normal women: influence of hormonal status

Obstructive sleep apnea is a disorder with astrong male predominance. One possible explanation could be an effectof female hormones on pharyngeal dilator muscle activity. Therefore, we determined the level of awake genioglossus electromyogram (EMGgg) andupper airway resistance in 12 pre- and 12 postmenopausal women underbasal conditions and during the application of an inspiratory resistiveload (25 cmH₂O · l¹ · s).In addition, a subgroup of eight postmenopausal women were studied asecond time after 2 wk of combined estrogen and progesterone replacement in standard doses. Peak phasic and tonic genioglossus activity, expressed as a percentage of maximum, were highest in theluteal phase of the menstrual cycle (phasic 23.9 ± 3.8%, tonic 10.2 ± 1.0%), followed by the follicular phase (phasic 15.5 ± 2.2%, tonic 7.3 ± 0.8%), and were lowest in the postmenopausal group (phasic 11.3 ± 1.6%, tonic of 5.0 ± 0.6), whereas upper airway resistance did not differ. There was a weak but significant positive correlation between progesterone levels and both peak phasic(P < 0.05) and tonic(P < 0.01) EMGgg. Finally, there was a significant increase in EMGgg in the postmenopausal group restudied after hormone therapy. In conclusion, female hormones (possibly progesterone) have a substantial impact on upper airway dilator muscleactivity.

     

Tonic contractions allow metabolic recuperation of the adductor muscle during escape responses of giant scallop Placopecten magellanicus

To escape from starfish predators, giant scallops, Placopecten magellanicus, swim using series of strong phasic contractions interrupted by tonic contractions. To investigate whether these tonic contractions allow metabolic recuperation of the adductor muscle, we sampled scallops at rest (Control), after an initial series of phasic contractions (Phasic) and after 1 min of tonic contraction following their initial phasic contractions (Phasic + Tonic) and compared muscle levels of phosphoarginine, adenylate nucleotides (ATP, ADP and AMP) and adenylate energy charge (AEC). Scallops in the two active groups did not differ in the numbers of phasic contractions or the mean phasic force production. Phosphoarginine concentrations in the adductor muscle decreased with phasic activity and remained low after 1 min of tonic contraction. ATP and ADP and total adenylate levels did not differ between the three groups, but AMP levels were higher in the scallops sampled after phasic contractions than in control scallops. The AEC was reduced by phasic contractions but returned to control levels after 1 min of tonic contraction. A significant negative correlation between AEC and the number of claps in the Phasic group disappeared in the Phasic + Tonic group. Thus, tonic contractions following phasic contractions allow partial metabolic recovery of the adductor muscle by returning AEC to control levels. However, phosphoarginine levels did not recover during tonic contractions, and a negative correlation between the number of claps and phosphoarginine levels remained in the Phasic + Tonic group. By interspersing tonic contractions between series of phasic contractions, scallops improved muscle energetic status, which should help maintain phasic force production during the remainder of the escape response.     

Genetic influences on Alzheimer's disease: evidence of interactions between the genes APOE, APOC1 and ACE in a sample population from the South of Brazil

Alzheimer’s disease is a complex neurodegenerative disorder. Several genes have been suggested as Alzheimer’s susceptibility factors, the apolipoprotein E (APOE) gene being an established susceptibility gene and the genes coding angiotensin-converting enzyme (ACE) and apolipoprotein C1 (APOC1) being considered possible candidate genes for the disease. The objective of this study was to investigate the association of ACE and APOC1 gene polymorphisms with susceptibility to Alzheimer’s disease and dementia in general, both alone and combined with the APOE gene. Forty-seven patients with dementia in general (35 of them with Alzheimer’s disease) and 85 controls were investigated. The haplotypes E*3/−317*ins and E*4/−317*ins of APOE/APOC1 genes were significantly more frequent in the groups with Alzheimer′s disease and dementia in general (P < 0.001). The frequency of the ACE*ins allele was also greater in the groups with Alzheimer’s disease and dementia in general (P = 0.022; P = 0.045), but genotype frequencies were only different in groups without the E*4/−317*ins haplotype (P = 0.012 for Alzheimer’s disease; P = 0.04 for dementia). Our data point to important genetic interactions involved in these diseases.     

A large-scale candidate gene association study of age at menarche and age at natural menopause

Recent genome-wide association (GWA) studies have identified several novel genetic loci associated with age at menarche and age at natural menopause. However, the stringent significance threshold used in GWA studies potentially led to false negatives and true associations may have been overlooked. Incorporating biologically relevant information, we examined whether common genetic polymorphisms in candidate genes of nine groups of biologically plausible pathways and related phenotypes are associated with age at menarche and age at natural menopause. A total of 18,862 genotyped and imputed single nucleotide polymorphisms (SNPs) in 278 genes were assessed for their associations with these two traits among a total of 24,341 women from the Nurses’ Health Study (NHS, N = 2,287) and the Women’s Genome Health Study (WGHS, N = 22,054). Linear regression was used to assess the marginal association of each SNP with each phenotype. We adjusted for multiple testing within each gene to identify statistically significant SNP associations at the gene level. To evaluate the overall evidence for an excess of statistically significant gene associations over the proportion expected by chance, we applied a one-sample test of proportion to each group of candidate genes. The steroid-hormone metabolism and biosynthesis pathway was found significantly associated with both age at menarche and age at natural menopause (P = 0.040 and 0.011, respectively). In addition, the group of genes associated with precocious or delayed puberty was found significantly associated with age at menarche (P = 0.013), and the group of genes involved in premature ovarian failure with age at menopause (P = 0.025).     

An Epidemiological Survey of Blood Lead Level in Tibetan Youth 10–18 Years Old in Songpan,China

There are few studies on Tibetan youth’s blood lead level (BLL) and environmental pollution in China. The objective of this project was to conduct a preliminary investigation on the blood lead level of Tibetan youth. Chinese Han youth’s BLL was also investigated as a control group. A total of 846 Tibetan youth and 785 Han youth were tested for BLL from September to October in 2007. Both of the mean BLL (6.4 μg/dL) and the frequency of high BLL (≥10 μg/dL) of Tibetan youth (7.7%, 65 of 846) were lower than those of Han youth (6.7 μg/dL; 13.2%, 104 of 785). But they are still higher compared with the BLL of youth in developed countries (1.1 μg/dL; USA 2005 census). The BLL of boys was significantly higher than that of girls, both in Tibetan and Han youth (p = 0.033 and p = 0.000, respectively). The study shows that Chinese Han and Tibetan youth's lead poisoning prevention and treatment lags far behind developed countries. These findings have implications for environmental health policy.     

GABAergic disinhibition changes the recovery cycle of bat inferior collicular neurons

This study examines the contribution of GABAergic inhibition to the discharge pattern and recovery properties of 110 bat inferior collicular neurons by means of bicuculline application to their recording sites. When stimulated with single pulses, 74 (67%) neurons discharged one or two impulses (phasic responders), 19 (17%) discharged three to ten impulses (phasic bursters) and 17 (16%) discharged impulses throughout the entire stimulus duration (tonic responders). Bicuculline application changed phasic responders into phasic bursters or tonic responders, increased the number of impulses by 10–2000% and shortened the response latency of most neurons. When stimulated with pairs of sound pulses, the recovery cycles of these neurons can be described as: (1) long inhibition (n = 49, 45%); (2) short inhibition (n = 41, 37%); and (3) fast recovery (n = 20, 18%) based upon the 50% recovery time that was either longer than 20 ms, between 10 and 20 ms or shorter than 10 ms. Bicuculline application shortened the 50% recovery time of most neurons by 11–2350% allowing them to respond to pairs of sound pulses at very short interpulse intervals. These data demonstrate that GABAergic inhibition contributes significantly to auditory temporal processing. Accepted: 18 April 1997     

Phylogeographic patterns and conservation units of a vulnerable species,Cabot’s tragopan (<Emphasis Type="Italic">Tragopan caboti</Emphasis>), endemic to southeast China

Cabot’s tragopan (Tragopan caboti) is a pheasant endemic to southeast China and is protected under both national and global legislation due to ongoing decline in population size and increased habitat fragmentation. We investigated the phylogeographic patterns and examined the consistency between evolutionary units and assumed subspecies taxonomy in this species. Six populations across the whole species presenting a wide distribution range were sampled and two mitochondrial DNA segments (control region, CR and cytochrome b, cyt b) were used in this study. The results demonstrated a high level of genetic diversity (h = 0.97 in CR and 0.78 in cyt b) and significant differentiation among populations. Phylogenetic analyses strongly indicated two reciprocally monophyletic clades named the “West group” and “East group” that were not consistent with the present subspecies regional distribution. The divergence time between the two groups was estimated to be around 5.54 × 10⁵–8.7 × 10⁵ years ago, and the expansion times of the two groups were close (about 3 × 10⁵ years ago), indicating the effect of glaciation in intraspecific differentiation. Based on the results of genetic analyses combined with geographic isolation and distinct population history, our findings suggest that two management units (MUs) should be defined in T. caboti for conservation.     

Species of <Emphasis Type="Italic">Neohaliotrema</Emphasis> Yamaguti, 1965 (Monogenea: Ancyrocephalidae) from the pomacentrid <Emphasis Type="Italic">Abudefduf vaigensis</Emphasis> (Quoy &; Gaimard) off Pulau Langkawi,Malaysia, with a revised diagnosis of the genus and a key to its species

Four new and one unidentified species of Neohaliotrema Yamaguti, 1965 were obtained from the gills of the Indo-Pacific sergeant Abudefduf vaigensis (Quoy & Gaimard) off Pulau Langkawi, Malaysia. The five species, N. malayense n. sp., N. bombini n. sp., N. andamanense n. sp., N. parvum n. sp. and an unidentified Neohaliotrema sp. (similar to N. macracanthum Zhukov, 1976), are described and distinguished based mainly on features of the haptor. Species of this genus are divisible into two groups, the ‘maomao group’, with two pairs of morphometrically modified ‘marginal’ hooks and a fenestrated haptor, and the ‘gracile group’, with morphologically similar marginal hooks and an entire haptor. With the exception of N. bombini n. sp., the species described fit within the ‘maomao group’. It is suggested that the more complex Neohaliotrema species of the ‘maomao group’ have modified hooks 1 and 2 on a haptoral ‘isthmus’ between two large apertures, i.e. ‘windows’, whereas the less complex species lacking these features are those of the ‘gracile group’. Neohaliotrema spp. have only a single pair of pigmented eye-spots. A fenestrated haptor is unique to the Neohaliotrema spp. of the ‘maomao group’. The generic diagnosis of Neohaliotrema is amended to include new data and a key to its known species is presented.     

Tissue and blood levels of zinc, copper, and magnesium in nitric oxide synthase blockade-induced hypertension

The aim of this study was to determine the levels of tissue and blood zinc (Zn), copper (Cu), magnesium (Mg) in nitric oxide (NO) synthase blockade-induced hypertension. A group of albino rats received a NO synthase inhibitor, N ^G -nitro-l-arginine-methyl ester (l-NAME, 60 mg/kg/d) in their drinking water for 21 d. l-NAME intake caused a progressive rise in this group’s resting mean arterial blood pressure compared to a control group (p<0.01). There were no differences between the groups with regard to tissue and blood levels of Zn or Cu; however, Mg concentrations were significantly lower in the hypertensive rats’ erythrocytes (20.2% reduction from control levels), cerebral cortex (17.0%), heart (9.1%), renal cortex (12%), renal medulla (16.7%), and in the tissues of the caval vein (23.7%), mesenteric artery (29.8%), renal artery (18.4%), and renal vein (22.1%). There were no significant Mg concentration changes in the hypertensive group’s plasma, cerebellum, liver, duodenum, or aortal tissue. These findings suggest that Mg depletion may play a role in the blood pressure rise that occurs in the model of chronic NO synthase inhibition-induced hypertension.     

Potential role of Neuregulin 1 and TNF-alpha (−308) polymorphism in schizophrenia patients visiting hospitals in Lahore,Pakistan

Schizophrenia is a chronic and disabling disease of the brain. Schizophrenic patients have auditory hallucinations, delusions and reduced social skills. Recent studies suggest that the genetic polymorphisms are linked with development of schizophrenia. Polymorphisms of schizophrenia susceptibility and different cytokine genes act as the genetic markers. The objective of our study is to examine the association between the neuregulin 1 and tumor necrosis factor-α (−308) gene polymorphism with schizophrenia. This association was performed on the basis of molecular biology to screen the mutations of neuregulin 1 and tumor necrosis factor-α (−308) gene in schizophrenic patients by polymorphism analysis. Statistical analysis of the observed data shows that there was an association (P = 0.003) between patient’s group and controls in terms of genotypes of single-nucleotide polymorphism 1 rather than single-nucleotide polymorphism 2 of neuregulin 1. So, heterozygous (adenine/guanine) allelic pattern can be a higher risk factor of schizophrenic patients. Polymorphism of tumor necrosis factor-α (−308) gene indicated frequent presence of homozygous (adenine/adenine) allelic pattern in patient’s group than in controls (P = 0.015). Statistical analysis indicates that the age distribution has significant difference between patient’s group and controls (P = 0.022) while the gender ratio is not significantly different (P = 0.366) between the two groups. It was concluded that in Pakistani population the neuregulin 1 and tumor necrosis factor-α (−308) genes are strongly associated with schizophrenia.     

Influence of the Selected Antioxidants on the Stability of the Celsior Solution Used for Perfusion and Organ Preservation Purposes

The purpose of the following research was to improve the original Celsior solution in order to obtain a higher degree of stability and effectiveness. The solution was modified by the addition of selected antioxidants such as vitamin C, cysteine, and fumaric acid in the following concentrations: 0.1, 0.3, and 0.5 mmol/l. The solution’s stability was estimated using an accelerated stability test based on changes in histidine concentrations in the solution using Pauly’s method for determining concentrations. Elevated temperatures, the factor accelerating substances’ decomposition reaction rate, were used in the tests. The research was conducted at four temperatures at intervals of 10°C: 60 ± 0.2°C, 70 ± 0.2°C, 80 ± 0.2°C, and 90 ± 0.2°C. It was stated that the studied substances’ decomposition occurred in accordance with the equation for first-order reactions. The function of the logarithmic concentration (log%C) over time was revealed to be rectilinear. This dependence was used to determine the kinetics of decomposition reaction rate parameters (the rate constant of decomposition k, activation energy E _a, and frequency factor A). On the basis of these parameters, the stability of the modified solution was estimated at +5°C. The results obtained show that the proposed antioxidants have a significant effect on lengthening the Celsior solution’s stability. The best results were reached when combining two antioxidants: vitamin C and cysteine in 0.5 mmol/l concentrations. As a result, the Celsior solution’s stability was lengthened from 22 to 299 days, which is 13.5 times. Vitamin C at a concentration of 0.5 mmol/l increased the solution’s stability by 5.2 times (t ₉₀ = 115 days), cysteine at a concentration of 0.5 mmol/l caused a 4.4 times stability increase (t ₉₀ = 96 days), and fumaric acid at a concentration of 0.5 mmol/l extended the stability by 2.1 times (t ₉₀ = 48 days) in relation to the original solution.     

The Effect of Biofeedback on Function in Patients with Heart Failure

Decreased HRV has been consistently associated with increased cardiac mortality and morbidity in HF patients. The aim of this study is to determine if a 6-week course of heart rate variability (HRV) biofeedback and breathing retraining could increase exercise tolerance, HRV, and quality of life in patients with New York Heart Association Class I-III heart failure (HF). Participants (N = 29) were randomly assigned to either the treatment group consisting of six sessions of breathing retraining, HRV biofeedback and daily practice, or the comparison group consisting of six sessions of quasi-false alpha-theta biofeedback and daily practice. Exercise tolerance, measured by the 6-min walk test (6MWT), HRV, measured by the standard deviation of normal of normal beats (SDNN), and quality of life, measured by the Minnesota Living with Congestive Heart Failure Questionnaire, were measured baseline (week 0), post (week 6), and follow-up (week 18). Cardiorespiratory biofeedback significantly increased exercise tolerance (p = .05) for the treatment group in the high (≥31%) left ventricular ejection fraction (LVEF) category between baseline and follow-up. Neither a significant difference in SDNN (p = .09) nor quality of life (p = .08), was found between baseline and follow-up. A combination of HRV biofeedback and breathing retraining may improve exercise tolerance in patients with HF with an LVEF of 31% or higher. Because exercise tolerance is considered a strong prognostic indicator, cardiorespiratory biofeedback has the potential to improve cardiac mortality and morbidity in HF patients.

Responses of midbrain lateral line units of the goldfish, Carassius auratus, to constant-amplitude and amplitude-modulated water wave stimuli

 Responses of mechanosensory lateral line units to constant-amplitude hydrodynamic stimuli and to sinusoidally amplitude-modulated water movements were recorded from the goldfish (Carassius auratus) torus semicircularis. Responses were classified by the number of spikes evoked in the unit's dynamic range and by the degree of phase locking to the carrier- and amplitude-modulation frequency of the stimulus. Most midbrain units showed phasic responses to constant-amplitude hydrodynamic stimuli. For different units peri-stimulus time histograms varied widely. Based on iso-displacement curves, midbrain units prefered either low frequencies (≤33 Hz), mid frequencies (50–100 Hz), or high frequencies (≥200 Hz). The distribution of the coefficient of synchronization to constant-amplitude stimuli showed that most units were only weakly phase locked. Midbrain units of the goldfish responded to amplitude-modulated water motions in a phasic/tonic or tonic fashion. Units highly phase locked to the amplitude modulation frequency, provided that modulation depth was at least 36%. Units tuned to one particular amplitude modulation frequency were not found. Accepted: 10 July 1999     

Genetic analysis of two Portuguese populations of <Emphasis Type="Italic">Ruditapes decussatus</Emphasis> by RAPD profiling

The clam Ruditapes decussatus is commercially important in the south of Portugal. The random amplified polymorphic DNA (RAPD) technique was applied to assess the genetic diversity and population structure of two Portuguese populations occurring in the Ria Formosa (Faro) and the Ria de Alvor, respectively. Twenty-five individuals of each population were investigated by RAPD profiles. Genetic diversity within populations, measured by the percentage of polymorphic loci (%P), varied between 68.57% (Alvor) and 73.88% (Faro). Shannon’s information index (H) and Nei’s gene diversity (h) were 0.281 and 0.176, respectively, for the Alvor population and 0.356 and 0.234 for the Faro population. Overall, genetic variation within R. decussatus populations was high. The total genetic diversity (H _T) was explained by a low variation between populations (G _ST = 0.145), which is consistent with high gene flow (N _m = 2.9). The analysis of molecular variance (AMOVA) showed that 65% of variability is within populations and 35% between populations (Φ_PT = 0.345; P ≥ 0.001). The value of Nei’s genetic distance was 0.0881, showing a low degree of population genetic distance, despite the different geographic origin. This is the first study on the population genetics of R. decussatus by RAPD technique. The results may be useful for restocking programs and aquaculture.     

Telomere length is associated with types of chromosome 21 nondisjunction: a new insight into the maternal age effect on Down syndrome birth

Advanced maternal age is a well-documented risk factor of chromosome 21 nondisjunction in humans, but understanding of this association at the genetic level is still limited. In particular, the state of maternal genetic age is unclear. In the present study, we estimated maternal genetic age by measuring telomere length of peripheral blood lymphocytes among age-matched mothers of children with Down syndrome (cases: N = 75) and mothers of euploid children (controls: N = 75) in an age range of 18–42 years. All blood samples were taken within 1 week of the birth of the child in both cases and controls. The telomere length estimation was performed by restriction digestion—Southern blot hybridization method. We stratified the cases on the basis of centromeric STR genotyping into maternal meiosis I (N = 48) and maternal meiosis II (N = 27) nondisjunction groups and used linear regression to compare telomere length as a function of age in the euploid, meiosis I and meiosis II groups. Our results show that all three groups have similar telomere length on average for younger mothers. As age increases, all groups show telomere loss, but that loss is largest in the meiosis II mother group and smallest in the euploid mother group with the meiosis I mother group in the middle. The regression lines for all three were statistically significantly different from each other (p < 0.001). Our results do not support the theory that younger women who have babies with Down syndrome do so because are ‘genetically older’ than their chronological age, but we provide the first evidence that older mothers who have babies with Down syndrome are “genetically older” than controls, who have euploid babies at the same age. We also show for the first time that telomere length attrition may be associated in some way with meiosis I and meiosis II nondisjunction of chromosome 21 and subsequent Down syndrome births at advanced maternal age.     

Heart Rate Variability During Sleep Following the Practice of Cyclic Meditation and Supine Rest

Day time activities are known to influence the sleep on the following night. Cyclic meditation (CM) has recurring cycles. Previously, the low frequency (LF) power and the ratio between low frequency and high frequency (LF/HF ratio) of the heart rate variability (HRV) decreased during and after CM but not after a comparable period of supine rest (SR). In the present study, on thirty male volunteers, CM was practiced twice in the day and after this the HRV was recorded (1) while awake and (2) during 6 h of sleep (based on EEG, EMG and EGG recordings). This was similarly recorded for the night’s sleep following the day time practice of SR. Participants were randomly assigned to the two sessions and all of them practiced both CM and SR on different days. During the night following day time CM practice there were the following changes; a decrease in heart rate, LF power (n.u.), LF/HF ratio, and an increase in the number of pairs of Normal to Normal RR intervals differing by more than 50 ms divided by total number of all NN intervals (pNN50) (P < 0.05, in all cases, comparing sleep following CM compared with sleep following SR). No change was seen on the night following SR. Hence yoga practice during the day appears to shift sympatho-vagal balance in favor of parasympathetic dominance during sleep on the following night.     

Monogeneans of the grouper Epinephelus tauvina (Perciformes, Serranidae) off Moorea, French Polynesia, with a description of Pseudorhabdosynochus pai n. sp. (Monogenea: Diplectanidae)

Specimens of the greasy grouper Epinephelus tauvina (Forssk?l), caught off Moorea, French Polynesia, harboured four species of gill monogeneans. The diplectanid Pseudorhabdosynochus pai n. sp. is characterised by an extremely big male quadriloculate organ (inner length 77 μm, cone length 15, tube length 47), the largest of all members of the genus, and a sclerotised vagina with a very complex structure, including three secondary chambers instead of one as in most species. Pseudorhabdosynochus sp. is a species of the ‘cupatus group’; this species is not formally described but various measurements are provided. The ancyrocephalid Haliotrema sp. and the capsalid Benedenia sp. were rare; they are both mentioned but not described. The diplectanid fauna of E. tauvina corresponds to the pattern already found in a clade of grouper species, the members of which often harbour both a species of the ‘cupatus group’ and another species of Pseudorhabdosynochus Yamaguti, 1958.

---

Résumé  Des spécimens du mérou Epinephelus tauvina (Forssk?l) pêchés à Moorea, Polynésie Fran?aise, hébergeaient quatre espèces de monogènes sur les branchies. Le Diplectanidae Pseudorhabdosynochus pai n. sp. est caractérisé par un organe tétraloculé male de très grande taille (longueur interne 77 μm, longueur du c?ne 15, longueur du tube 47), le plus grand de toutes les espèces du genre, et un vagin sclérifié à structure très complexe, comprenant trois chambres secondaires, au lieu d’une comme c’est le cas chez la plupart des autres espèces. Pseudorhabdosynochus sp. est une espèce du ‘groupe cupatus’ qui n’est pas formellement décrite, mais des mesures sont indiquées. Un Ancyrocephalidae, Haliotrema sp., et un Capsalidae, Benedenia sp., étaient rares, et sont mentionnés mais non décrits. La faune des Diplectanidae de E. tauvina correspond au patron déjà trouvé dans un clade d’espèces de mérous, dont les membres hébergent souvent à la fois une espèce du ‘groupe cupatus’ et une autre espèce de Pseudorhabdosynochus Yamaguti, 1958.

     

Altered Platelet Monoamine Oxidase-B Activity in Idiopathic Parkinson’s Disease

A case-control study was undertaken to investigate the status of platelet monoamine oxidase-B (MAO-B) activity in Indian cases of idiopathic Parkinson’s disease. A significant increase in the activity of platelet MAO-B was observed in Parkinson’s cases (n = 26) as compared to controls (n = 26). No significant change in the activity of the enzyme was observed while the data was analysed with respect to age, sex and duration of disease. A trend of decrease in platelet MAO-B activity was observed in Parkinson’s cases with respect to stage although the change was not significant. No correlation in platelet MAO-B activity was observed with respect to age and sex in the control subjects. Parkinson’s cases treated with L-DOPA and MAO-B inhibitor exhibited decreased platelet MAO-B activity as compared to drug naive cases and those treated with L-DOPA alone. Interestingly, Parkinson’s cases treated with L-DOPA and amantadine also had lower platelet MAO-B activity as compared to drug naive cases and those treated with L-DOPA alone. Activity of platelet MAO-B in Parkinson’s patients was increased in naive cases and those treated with L-DOPA alone or in combination with other drugs compared to controls. The results of the present study indicate that phenotypic activity of platelet MAO-B is high in Indian Parkinson’s cases. Further, action mechanism of drugs used in the treatment of Parkinson’s disease could be understood by assay of platelet MAO-B activity. It is an interesting observation and may be looked further in large number of cases.     

Combined effects of niacin and chromium treatment on vascular endothelial dysfunction in hyperlipidemic rats

Combined treatment with niacin and chromium has been found to have a protective effect against oxidative damage to different tissues of hyperlipidemic rats. But its effects on vascular endothelial dysfunction are less clear. This study was performed to investigate the effect of combined treatment with niacin and chromium on vascular endothelial dysfunction, with the aim of gaining insight to the mechanisms by detecting the expression levels of ox-LDL and LOX-1. Twenty-four male, 4-week-old Wistar rats were randomly divided into three groups: control group (CG; n = 8), high-fat group (HF; n = 8), and drug control group (DG; n = 8).In CG group, rats were fed with pellet chow. In HF group, rats were fed with high-fat diet for 12 weeks. In DG group, rats were fed with the same high-fat diet and treated with CrCl₃ · 6H₂O (250 μg/kg days) and niacin (100 mg/kg days) by gavage technique for 12 weeks. At the end of the 12th week, samples from aorta and blood were collected. In HF group, the serum levels of total cholesterol (TC), low-density lipoprotein (LDL), oxidized low-density lipoprotein (ox-LDL) and endothelin (ET) were higher, whereas the levels of high-density lipoprotein (HDL), serum NO were lower than those in CG group. The levels of serum TC, LDL, ox-LDL and ET decreased and HDL, NO levels increased in DG group when compared with HF group. The levels of LOX-1, ICAM-1 were also observed in abdominal artery. In HF group, the protein and mRNA expression of LOX-1, ICAM-1 were elevated comparing with CG group. In DG group, the protein and mRNA expression of LOX-1, ICAM-1 were decreased obviously, but still differed significantly from those in CG group. ox-LDL was related positively to TC, LDL, ET, ICAM-1 and LOX-1, but related negatively to NO and HDL. These findings indicated that combined treatment with niacin and chromium has potential therapeutic protection of endothelial function by down-regulating ox-LDL/LOX-1 signaling pathway.