Detection of Chlamydia pneumoniae in atherosclerotic tissue: a comparative study of PCR and immunocytochemistry

The reported prevalence of Chlamydia pneumoniae in atherosclerotic tissue appears to depend on the detection system used. This introduces problems in determining the role of C. pneumoniae in atherosclerosis. This study analyses the sensitivity and performance of molecular diagnostic methods for the detection of C. pneumoniae and polymerase chain reaction (PCR) inhibitors in atheromatous tissue. Atherosclerotic tissue taken from 30 coronary endarterectomies, nine coronary arteries from explanted hearts, 16 carotid and two femoral endarterectomies are studied. Nested PCR (nPCR) assays targeting the PstI restriction fragment, the OmpA gene and the CRP operon of the chlamydial genome and immunocytochemistry (ICC) are used. Internal controls (IC) are constructed to co-amplify with the specific amplicons and identify the presence of inhibitor. The OmpA, PstI and CRP operon PCR assays had similar analytical sensitivities. However, the OmpA PCR was most affected by PCR inhibitors. Despite this, eight samples (14%) tested positive in the OmpA nPCR and no positives were found using the PstI or CRP operon nPCRs. Primary isolates of C. pneumoniae obtained from 12 patients with acute respiratory infection were positive in all three assays. Of the 48 specimens available for ICC, 33 (69%) were positive for chlamydial antigens. These included samples found positive by PCR. Dilution of samples to eliminate PCR inhibitors may have contributed to the discordant ICC and PCR results. The OmpA PCR, when used with an IC to identify samples with PCR inhibitors, is a reliable tool. However, the sensitivity of the ICC methods justifies their continued use.

Long-term evaluation of deep brain stimulation of the thalamus

Object

The effects of thalamic deep brain stimulation (DBS) on essential tremor (ET) and Parkinson disease (PD) have been well documented, but there is a paucity of long-term data. The aim of this study was to evaluate the longterm safety and efficacy of DBS of the ventralis intermedius nucleus (VIM) of the thalamus for PD and ET.

Methods

Thirty-eight of 45 patients enrolled at five sites completed a 5-year follow-up study. There were 26 patients with ET and 19 with PD undergoing 29 unilateral (18 ET/11 PD) and 16 bilateral (eight ET/eight PD) procedures. Patients with ET were evaluated using the Tremor Rating Scale, and patients with PD were evaluated using the Unified Parkinson’s Disease Rating Scale. The mean age of patients with ET was 70.2 years and 66.3 years in patients with PD. Unilaterally implanted patients with ET had a 75% improvement of the targeted hand tremor; those with bilateral implants had a 65% improvement in the left hand and 86% in the right compared with baseline. Parkinsonian patients with unilateral implants had an 85% improvement in the targeted hand tremor and those with bilateral implants had a 100% improvement in the left hand and 90% improvement in the right. Common DBS-related adverse events in patients receiving unilateral implants were paresthesia (45%) and pain (41%), and in patients receiving implants bilaterally dysarthria (75%) and balance difficulties (56%) occurred. Device-related surgical revisions other than IPG replacements occurred in 12 (27%) of the 45 patients.

Conclusions

Thalamic stimulation is safe and effective for the long-term management of essential and parkinsonian tremors. Bilateral stimulation can cause dysarthria and incoordination and should be used cautiously.

Assessing reliability of microsatellite genotypes from kit fox faecal samples using genetic and GIS analyses

Noninvasive faecal DNA sampling has the potential to provide a wealth of information necessary for monitoring and managing endangered species while eliminating the need to capture, handle or observe rare individuals. However, scoring problems, and subsequent genotyping errors, associated with this monitoring method remain a great concern as they can lead to misidentification of individuals and biased estimates. We examined a kit fox scat data set (353 scats; 80 genotypes) for genotyping errors using both genetic and GIS analyses, and evaluated the feasibility of combining both approaches to assess reliability of the faecal DNA results. We further checked the appropriateness of using faecal genotypes to study kit fox populations by describing information about foxes that we could deduce from the 'acceptable' scat genotypes, and comparing it to information gathered with traditional field techniques. Overall, genetic tests indicated that our data set had a low rate of genotyping error. Furthermore, examination of distributions of scat locations confirmed our data set was relatively error free. We found that analysing information on sex primer consistency and scat locations provided a useful assessment of scat genotype error, and greatly limited the amount of additional laboratory work that was needed to identify potentially 'false' scores. 'Acceptable' scat genotypes revealed information on sex ratio, relatedness, fox movement patterns, latrine use, and size of home range. Results from genetic and field data were consistent, supporting the conclusion that our data set had a very low rate of genotyping error and that this noninvasive method is a reliable approach for monitoring kit foxes.

Abdominal diameter index: a more powerful anthropometric measure for prevalent coronary heart disease risk in adult males

AIM

The authors wished to compare the strength of association of several anthropometric measures of body size and fat distribution among themselves and in comparison with other known risk factors for prevalent coronary heart disease (CHD).

METHODS

Prevalent CHD was assessed in 466 middle-aged, male, multiracial Triborough Bridge and Tunnel Authority officers in New York City by verified history, electrocardiogram or exercise stress test. Anthropometric measures included body mass index, waist, hip and thigh circumferences, waist-hip ratio, waist-thigh ratio, sagittal abdominal diameter and abdominal diameter index (sagittal abdominal diameter/thigh circumference). Results were compared with other CHD risk factors measured simultaneously (history of diabetes, smoking, blood pressure, lipid profile, apolipoproteins A and B, lipoprotein (a), homocysteine, fibrinogen, urinary microalbumin, serum vitamin E and ferritin) and a calculated 10-year CHD risk using a Framingham algorithm (10-year Framingham CHD risk).

RESULTS

CHD was found in 29 individuals. Of the six anthropometric measures, abdominal diameter index gave the largest and most significant standardized odds ratio (OR) for CHD [1.80, 95% confidence interval (CI) 1.20, 2.71], equivalent to 10-year Framingham CHD risk. Men in the highest compared with the lowest tertile of abdominal diameter index had a univariate OR of 5.47 (95% CI 1.55, 19.28) which was the only anthropometric measure that remained significant after adjusting for 10-year Framingham CHD risk.

CONCLUSIONS

For middle-aged American men, abdominal diameter index may be the most powerful anthropometric measure of risk for prevalent CHD.

Effects of Aggressive Versus Conventional Lipid-Lowering Therapy by Simvastatin on Human Atherosclerotic Lesions

OBJECTIVES

This study sought to compare the effects of aggressive and conventional lipid lowering by two different dosages of the same statin on early human atherosclerotic lesions using serial noninvasive magnetic resonance imaging (MRI).

BACKGROUND

Regression of atherosclerotic lesions by lipid-lowering therapy has been reported.

METHODS

Using a double-blind design, newly diagnosed hypercholesterolemic patients (n = 51) with asymptomatic aortic and/or carotid atherosclerotic plaques were randomized to 20 mg/day (n = 29) or 80 mg/day (n = 22) simvastatin. Mean follow-up was 18.1 months. A total of 93 aortic and 57 carotid plaques were detected and sequentially followed up by MRI every six months after lipid-lowering initiation. The primary MRI end point was change in vessel wall area (VWA) as a surrogate for atherosclerotic burden.

RESULTS

Both statin doses reduced significantly total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C) versus baseline (p < 0.001). Total cholesterol decreased by 26% versus 33% and LDL-C by 36% versus 46% in the conventional (20 mg) versus aggressive (80 mg) simvastatin groups, respectively. Although the simvastatin 80-mg group had significantly higher baseline TC and LDL-C levels, both groups reached similar absolute values after treatment. A significant reduction in VWA was already observed by 12 months. No difference on vascular effects was detected between the randomized doses. Post-hoc analysis showed that patients reaching mean on-treatment LDL-C < or = 100 mg/dl had larger decreases in plaque size.

CONCLUSIONS

Effective and protracted lipid-lowering therapy with simvastatin is associated with a significant regression of atherosclerotic lesions. No difference in vessel wall changes was seen between high and conventional doses of simvastatin. Changes in vessel wall parameters are more related to LDL-C reduction rather than to the dose of statin.

Time course toxicogenomic profiles in CD-1 mice after nontoxic and nonlethal hepatotoxic paracetamol administration

Adverse drug reactions are a major clinical problem. Drug-induced hepatotoxicity constitutes a large percentage of these reactions. A thorough understanding of the genetic events, specifically, the early "decision-making" processes underlying biological changes caused by drugs and metabolites, is required. To assist in the understanding of these events, we have employed the model hepatotoxin, paracetamol (APAP), and GeneChip technology to investigate global genetic events seen after nontoxic and toxic doses in the mouse. Mice were dosed [vehicle, nontoxic APAP (1 mmol/kg), and toxic APAP (3.5 mmol/kg)], and individual hepatic RNA samples were hybridized to separate chips to determine interanimal variation. Statistical analysis detected 175 CD-1 mouse genes that were significantly regulated (P < 4.1 x 10(-6)), and nonsignificant genes were discarded. For clarity, the significantly regulated genes were then binned into categories according to their major function-antioxidant, glutathione, metabolism, transcription, immune, and apoptosis. There was no hepatic stress observed after dosing 1 mmol/kg APAP, when measured by serum alanine aminotransferase levels. Hepatic toxicity was observed at both 4 and 24 h after a 3.5 mmol/kg dose of APAP. Time course expression profiles for selected genes have been created. These results demonstrate that most active gene expression occurs around 4 h after a toxic dose of APAP. Down-regulation of these genes is observed over 24 h, coinciding with the development of overt toxicity. These data provide a deeper understanding of the in vivo time course of physiological responses of the liver to chemical stress and provide a logical step forward for the investigation of new chemical entities demonstrated positive in chemically reactive metabolite screens. The complete data set can be viewed at http://www.ebi.ac.uk/arrayexpress/. The accession number is E-MEXP-82.

Matrix metalloproteinase-9 expression is associated with the presence of Chlamydia pneumoniae in human coronary atherosclerotic plaques

OBJECTIVE

To investigate the association between Chlamydia pneumoniae and matrix metalloproteinase-9 (MMP-9) in atherosclerotic plaques.

DESIGN

31 coronary atherosclerotic plaque specimens were studied by immunohistochemistry, polymerase chain reaction (PCR), and reverse transcription PCR for the presence of C pneumoniae antigen and genomic DNA, and of MMP-9 protein and transcripts.

RESULTS

Immunohistochemical analysis identified a strong association between the presence of C pneumoniae antigen and production of MMP-9 in coronary atherosclerotic plaques (p = 0.001). Furthermore, analysis of the intralesional amount of C pneumoniae and MMP-9 indicated an increased number of cells positive for MMP-9 in arterial sections that had increased C pneumoniae positivity (p < 0.05).

CONCLUSIONS

This study provides evidence of an association between expression of MMP-9 and the intravascular presence of C pneumoniae and may suggest a potential pathological mechanism whereby C pneumoniae may contribute to the progression of coronary atherosclerosis.

New trends in lipid management: eight cases to consider

Eight case histories with differing clinical presentations and lipid abnormalities are presented to illustrate new trends in lipid management. Issues discussed include the use of coronary artery calcium scores to assess coronary heart disease risk for individuals who are asymptomatic, lower LDL-cholesterol goals, new lipid measurements that may be clinically helpful in patient management, and the use of combined lipid-altering agents.

Isolation, identification, and selection of lactic acid bacteria from alfalfa sprouts for competitive inhibition of foodborne pathogens

Several studies have investigated the control of pathogens on alfalfa sprouts, and some treatments have been shown to be effective in reducing pathogen populations. However, control methods investigated thus far only provide pathogen control at a given point in the sprouting process and can affect germination. Competitive inhibition of pathogens with lactic acid bacteria might provide pathogen control throughout the sprouting process and up to consumption. The purpose of this study was to isolate and identify lactic acid bacteria from alfalfa sprouts to inhibit the growth of foodborne pathogens. Fifty-eight lactic acid bacteria isolates were obtained from alfalfa seeds and sprouts. These isolates were evaluated for inhibitory action against Salmonella enterica, Escherichia coli O157:H7, and Listeria monocytogenes by agar spot tests. All pathogens were inhibited by 32 (55%) of the isolates, S. enterica by 56 (97%), E. coli O157:H7 by 49 (84%), and L. monocytogenes by 41 (71%). The isolates were identified by the Analytical Profile Index evaluation of carbohydrate utilization. Isolates obtained from a sample of alfalfa seeds and identified as Lactococcus lactis subsp. lactis showed zones of inhibition of 4.0 mm or greater for all pathogens. One of these isolates, Lactococcus lactis subsp. lactis (L7), and an isolate previously obtained, Pediococcus acidilactici (D3), were evaluated for competitive inhibition of S. enterica, E. coli O157:H7, and L. monocytogenes in deMan Rogosa Sharpe agar and broth. Pathogen populations were significantly reduced by day 5. The selected isolates will be further evaluated in future studies for inhibitory action toward S. enterica, E. coli O157:H7, and L. monocytogenes during sprouting.

Preservation of post-transplant lung function with aerosol cyclosporin

Post-lung transplant use of aerosol cyclosporin (ACsA) is considered by examining the relationship between deposited aerosol dose and effect. In a sub-study of placebo controlled trials of ACsA as a rejection prophylaxis, 15 drug subjects received aerosol dose quantification tests to gage their ability to effectively deposit the nebulised drug in their transplanted lung(s). A total of seven placebo subjects received mock deposition tests. The deposited doses and mock doses were compared to changes in the forced expiratory volume in one second, at six time points during the 2-yr trial period (ACsA was started within 6 weeks post-transplant). Linear relationships were demonstrated between deposited dose and improvement in lung function in the drug subjects at all intervals. Mock dose data from placebo subjects did not demonstrate similar correlation. Based on these results, subjects were grouped by dose and compared. Subjects depositing > or = 5 mg of the drug in the periphery of their transplant(s) had improving pulmonary function on average. Low-dose and placebo subjects demonstrated declines, more A2-A4 rejection events in the latter portion of the trial, and more chronic rejection beyond the end of the trial. A dose-to-effect relationship is demonstrated for aerosol cyclosporin in terms of pulmonary function and biopsy proven rejection.

Aerosol cyclosporin therapy in lung transplant recipients with bronchiolitis obliterans

The majority of patients who develop bronchiolitis obliterans, after lung transplantation, die within 2-3 yrs after onset since treatment with conventional immunosuppression is typically ineffective. A case/control study was conducted in lung transplant recipients with biopsy-documented bronchiolitis obliterans to determine whether aerosol cyclosporin use contributed to increased survival. The cases comprised 39 transplant recipients who received open-label aerosol cyclosporin treatment in addition to conventional immunosuppression. The controls were transplant recipients treated with conventional immunosuppression alone. There were 51 controls from the University of Pittsburgh Medical Center and 100 from a large multicentric database (Novartis Lung Transplant Database). Forced expiratory volume in one second expressed as a percentage of the predicted value was an independent predictor of survival in all patients with bronchiolitis obliterans. Cox proportional-hazards analysis revealed a survival advantage for aerosol cyclosporin cases compared to the Pittsburgh control group. A survival advantage was also seen when comparing study cases to multicentric controls. Aerosol cyclosporin, given with conventional immunosuppression to lung transplant recipients with bronchiolitis obliterans, provides a survival advantage over conventional therapy alone.

Apertureless near-field Raman spectroscopy

We report on the tip-enhanced Raman spectra of C60 obtained on a custom-built apertureless scanning near-field optical microscope. A commercial atomic force microscope tip coated with 100 nm thickness of gold was used to enhance locally the Raman signal and permit topographic and spectral information to be acquired simultaneously. We present preliminary data which demonstrate the tip enhancement effect using C60 as a test sample.

The disposition of voriconazole in mouse, rat, rabbit, guinea pig, dog, and human

Voriconazole is a new triazole antifungal agent with potent, wide-spectrum activity. Its pharmacokinetics and metabolism have been studied in mouse, rat, rabbit, dog, guinea pig, and humans after single and multiple administration by both oral and intravenous routes. Absorption of voriconazole is essentially complete in all species. The elimination of voriconazole is characterized by non-linear pharmacokinetics in all species. Consequently, pharmacokinetic parameters are dependent upon dose, and a superproportional increase in area under the curve is seen with increasing dose in rat and dog toxicology studies. Following multiple administration, there is a decrease in systemic exposure. This is most pronounced in mouse and rat, less so in dog, and not observed in guinea pig or rabbit. Repeat-dose toxicology studies in mouse, rat, and dog have demonstrated that induction of cytochrome P450 by voriconazole (autoinduction of metabolism) is responsible for the decreased exposure in these species. Autoinduction of metabolism is not observed in humans, and plasma steady-state concentrations remain constant with time. Voriconazole is extensively metabolized in all species. The major pathways in humans involve fluoropyrimidine N-oxidation, fluoropyrimidine hydroxylation, and methyl hydroxylation. Also, N-oxidation facilitates cleavage of the molecule, resulting in loss of the fluoropyrimidine moiety and subsequent conjugation with glucuronic acid. Major pathways are represented in animal species. The major circulating metabolite in rat, dog, and human is the N-oxide of voriconazole. It is not thought to contribute to efficacy since it is at least 100-fold less potent than voriconazole against fungal pathogens in vitro.

Cooperative regulation of myosin-actin interactions by a continuous flexible chain II: actin-tropomyosin-troponin and regulation by calcium

The model of myosin regulation by a continuous tropomyosin chain is generalized to a chain of tropomyosin-troponin units. Myosin binding to regulated actin is cooperative and initially inhibited by the chain as before. In the absence of calcium, myosin is further inhibited by the binding of troponin-I to actin, which through the whole of troponin pins the tropomyosin chain in a blocking position; myosin and TnI compete for actin and induce oppositely-directed chain kinks. The model predicts equilibrium binding curves for myosin-S1 and TnI as a function of their first-order affinities K(S1) and L(TI). Myosin is detached by the actin binding of TnI, but TnI is more efficiently detached by myosin when the kink size (typically nine to ten actin sites) spans the seven-site spacing between adjacent TnI molecules. An allosteric mechanism is used for coupling the detachment of TnI to calcium binding by TnC. With thermally activated TnI kinks (kink energy B approximately k(B)T), TnI also binds cooperatively to actin, producing cooperative detachment of myosin and biphasic myosin-calcium Hill plots, with Hill coefficients of 2 at high calcium and 4-6 at low calcium as observed in striated muscle. The theory also predicts the cooperative effects observed in the calcium loading of TnC.

Identification of the cytochrome P450 enzymes involved in the N-oxidation of voriconazole

Voriconazole is a triazole antifungal agent with potent activity against a broad spectrum of clinically significant pathogens. In vivo and in vitro studies have demonstrated that voriconazole is extensively metabolized, with the major circulating metabolite resulting from N-oxidation. In the present study, we report on the human cytochrome P450 enzymes responsible for the generation of this metabolite. In human liver microsomes voriconazole N-oxidation exhibited biphasic kinetics with K(m1) of 8.1 microM, and K(m2) of 835 microM. Studies at 2500 microM voriconazole identified CYP3A4 as the low-affinity component, with activity correlating strongly with CYP3A4 activity in a bank of human liver microsomes (r = 0.90) and inhibited by ketoconazole. At 25 microM, voriconazole N-oxidation showed strong correlation with CYP2C19 and CYP3A4 activity (r = 0.77 and 0.74, respectively) and was inhibited by both sulfaphenazole and ketoconazole. Incubations with recombinant enzymes suggested both CYP2C9 and CYP2C19 as high-affinity enzymes (K(m) values of 20 and 3.5 microM, respectively). Further studies used chemical inhibitors in human liver microsomes prepared from individual donors, including two CYP2C19 poor metabolizers. No inhibition was observed with sulfaphenazole, indicating a minor role for CYP2C9 in human liver, but inhibition by ketoconazole was most potent in the CYP2C19 poor metabolizer livers, suggesting an increased role for CYP3A4 in individuals lacking CYP2C19. These data indicate that voriconazole is a substrate for CYP2C9, CYP2C19, and CYP3A4, with CYP2C9 involvement being minimal in human liver microsomes. Genotype status for CYP2C19 and/or coadministration of drugs that modulate CYP2C19 or CYP3A4 activities could effect voriconazole plasma levels.

Cooperative regulation of myosin-actin interactions by a continuous flexible chain I: actin-tropomyosin systems

We present a model for cooperative myosin binding to the regulated actin filament, where tropomyosins are treated as a weakly-confined continuous flexible chain covering myosin binding sites. Thermal fluctuations in chain orientation are initially required for myosin binding, leaving kinked regions under which subsequent myosins may bind without further distortion of the chain. Statistical mechanics predicts the fraction of sites with bound myosin-S1 as a function of their affinities. Published S1 binding curves to regulated filaments with different tropomyosin isoforms are fitted by varying the binding constant, chain persistence length nu (in actin monomers), and chain kink energy A from a single bound S1. With skeletal tropomyosin, we find an S1 actin-binding constant of 2.2 x 10(7) M(-1), A = 1.6 k(B)T and nu = 2.7. Similar persistence lengths are found with yeast tropomyosin. Larger values are found for tropomyosin-troponin in the presence of calcium (nu = 3.7) and tropomyosins from smooth muscle and fibroblasts (nu = 4.5). The relationship of these results to structural information and the rigid-unit model of McKillop and Geeves is discussed.

Central nervous system inflammation is a hallmark of pathogenesis in mouse models of GM1 and GM2 gangliosidosis

Mouse models of the GM2 gangliosidoses [Tay-Sachs, late onset Tay-Sachs (LOTS), Sandhoff] and GM1 gangliosidosis have been studied to determine whether there is a common neuro-inflammatory component to these disorders. During the disease course, we have: (i) examined the expression of a number of inflammatory markers in the CNS, including MHC class II, CD68, CD11b (CR3), 7/4, F4/80, nitrotyrosine, CD4 and CD8; (ii) profiled cytokine production [tumour necrosis factor alpha (TNF alpha), transforming growth factor (TGF beta 1) and interleukin 1 beta (IL1 beta)]; and (iii) studied blood-brain barrier (BBB) integrity. The kinetics of apoptosis and the expression of Fas and TNF-R1 were also assessed. In all symptomatic mouse models, a progressive increase in local microglial activation/expansion and infiltration of inflammatory cells was noted. Altered BBB permeability was evident in Sandhoff and GM1 mice, but absent in LOTS mice. Progressive CNS inflammation coincided with the onset of clinical signs in these mouse models. Substrate reduction therapy in the Sandhoff mouse model slowed the rate of accumulation of glycosphingolipids in the CNS, thus delaying the onset of the inflammatory process and disease pathogenesis. These data suggest that inflammation may play an important role in the pathogenesis of the gangliosidoses.

Binding of dentin noncollagenous matrix proteins to biological mineral crystals: an atomic force microscopy study

Noncollagenous matrix proteins (NCPs) of dental hard tissues (dentin, cementum) are involved, both temporally and spatially, in the mineralization of their collagen matrices. Two of the NCPs thought to initiate mineral nucleation and control crystal growth in dentin, are dentin phosphoproteins (DPP) and dentin sialoprotein (DSP). Control of crystal growth would depend on the binding capacity of these two molecules, which may be related to the charge domains on the crystals and/or the phosphorylation of the protein. Phosphophoryn (a highly phosphorylated DPP) and DSP were isolated, purified, and characterized from the immature root apicies of human teeth. Dephosphorylation of phosphophoryn was carried out using bovine intestinal alkaline phosphatase. Enamel crystals were prepared from the maturation stage of developing rat incisor enamel. Protein-coated crystals were prepared for viewing in an atomic force microscope fluid cell using tapping mode. Desorption of the proteins was achieved using a phosphate buffer and surface roughness measurements were obtained from all specimens. Time-lapsed images of the crystals showed "nanospheres" of protein distributed along the crystals but only the phosphophoryn-coated crystals showed a distinctive banding pattern, which was still visible after the phosphate desorption experiments. The surface roughness measurements were statistically greater (P <0.01) when compared to the control for only the phosphophoryn-coated specimens. It is hypothesized that the phosphophoryn binding may be associated with charge arrays on the crystal surface and its phosphorylation. Also, based on its affinity for the crystalsurfaces, phosphophoryn seems the most likely candidate for controlling dentin crystal growth and morphology.