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PubMed1969

Separation of mono- and diglycerides by gas--liquid chromatography.

The parameters affecting the separation and quantification of trimethylsilyl ethers of mono- and diglycerides have been investigated by gas-liquid chromatography with QF-1 and SE-30 as stationary phases and a flame ionization detector. Results have been compared with those obtained earlier for triglycerides. The isothermal characteristics of a range of trimethylsilyl ethers of mono- and diglycerides on both stationary phases showed that log retention volume was directly proportional to carbon number and inversely proportional to absolute temperature. However, glyceride derivatives with lower carbon numbers deviated from these relationships. By using various rates of programmed temperature rise, we have determined the elution temperatures (Kelvin scale) of the mono- and diglyceride trimethylsilyl ethers relative to that of glycerol trilaurate. The "carbon equivalent of a trimethylsilyl group" is defined and shown to be useful in comparing the chromatographic properties of different glyceride classes. Weight and molar correction factors have been obtained and used to analyze diglycerides derived from egg and bovine brain lecithins.

Animals↗

PubMed1993

Pharmacokinetics of dilevalol and its conjugates in man. Assay method for plasma, blood, urine and bile samples and preliminary pharmacokinetic studies.

The renal and biliary excretion of the beta-adrenoceptor blocking agent dilevalol (CAS 75659-07-3) and its conjugates was examined in a preliminary pharmacokinetic study. Plasma, urine and bile dilevalol concentrations were determined with a simplified procedure that is based on alkaline liquid-liquid extraction using diethyl ether and subsequent reversed-phase HPLC separation of the reconstituted samples (on a PRP-1 stationary phase using a mixture of methanol and pH 9.8 carbonate buffer as mobile phase). Triamterene was used as internal standard. The quantification of the conjugates was accomplished indirectly via enzymatic hydrolysis (glusulase) with and without addition of the beta-glucuronidase inhibitor 1,4-saccharolactone (at a final concentration of 5.5 mmol/l). In the pharmacokinetic study healthy volunteers and cholecystectomised patients with a T-drain received a single oral dose of 200 mg dilevalol. Furthermore, to healthy volunteers an i.v. dose of 60 mg dilevalol was given in order to estimate the absolute bioavailability. From the obtained data the systemic plasma clearance was calculated to be 1708 ml/min. The oral bioavailability was calculated to be 16%. The log concentration-time curves of the metabolites paralleled those of dilevalol in the terminal section with average terminal half-lives of approx. 5 h. In volunteers the fractions of the dose excreted renally were 0.5% for parent drug, 23% for the glucuronide(s) and 8% for the sulfate. The corresponding values found for the patients were not significantly different. In the patients' bile only 1.2% of the total dose were found (0.03% dilevalol, 1.1% dilevalol glucuronide(s), 0.1% dilevalol sulfate).(ABSTRACT TRUNCATED AT 250 WORDS)

Bile↗

PubMed1980

[Quantification of the attenuation of pain sensation through evoked potentials after the application of mild analgesics (author's transl)].

Evoked potentials resulting from stimulation of tooth pulp with rectangular impulses were chosen for the indication of the analgesic activity of mild analgesics. If the stimuli were perceived subjectively as equally painful, the amplitudes of the evoked potentials were intraindividually well reproducible. The results are reproducible within one day as well as on different days. According to the large interindividual variation in the amplitude of the evoked potentials, the percentual reduction of the amplitude was a better measure for the analgesic action than the absolute height of the signal. Interindividually, the latencies have shown clear differences whereas they were reproducible for the individuum. The curves for: 1. The percentual reduction of the evoked potentials 2. The diminuation of the subjective pain response 3. The increase in the sensitivity threshold after the application of the drug were principally similar. The results indicate, that the evoked potentials may represent a more sensitive measure of experimentally induced pain in subjective methods.

Acetaminophen↗

PubMed1985

Quantification of endocytosis-derived membrane traffic.

The main data covered by this article have been summarized in Table I. A fairly uniform picture is obtained for endocytosis-derived membrane transfer and compartmentation. This may be due to the limited amount of information and the resulting low resolution. Data on mainly three cell types are presented: macrophages, fibroblasts and amoebae. The data vary as much for one cell type as between different cells. Therefore, no possible differences related to cell function emerge. More detailed data, for more cell types, may change the picture. The values for cell surface area, although significantly different in absolute terms (column S in Table I), are rather similar when related to cell diameter, all being about 3-fold in excess of the surface area of the smooth sphere of comparable volume (column xi in Table I). The rate of plasma membrane internalization for macrophages and amoebae both professional phagocytes, is about 2 cell surface area equivalents per h or more. This may be somewhat higher than for fibroblasts (column PM/h in Table I). The average residence time for membrane on the cell surface, therefore, is about 30 min. A most interesting finding seems to be the rather uniform values obtained for the average size (volume weighted) of primary pinosomes, being about 0.3 micron in diameter (column phi-Internalization in Table I). Due to their rapid increase in size as a result of fusion (cf. Fig. 2), it has not been feasible to directly measure the size of primary pinosomes by morphometric means. The values in Table I, give no information on the size distributions of primary pinosomes and on whether these consist of one or more size classes. The steady-state average diameter of pinosomes is noticeably larger than that of primary pinosomes (column phi-pinosomes in Table I; cf. Table II for Acanthamoebae). The corresponding decrease in surface-to-volume ratio can make about 50% of pinosomal membrane available for recycling directly from this membrane compartment. Membrane recycling from the pinosomal compartment occurs after an average residence time of about 3 min for macrophages and 4-6 min for fibroblasts (column tau-pinosomes in Table I). The relative pool size of intracellular membranes participating in shuttling to and from the cell surface is significantly different for animal cells and amoebae (column rho in Table I). For macrophages, fibroblasts, CHO cells, and mast cells, this intracellular membrane pool amounts to about 10-20% the plasma membrane area, compared to 150-200% in the case of amoebae.(ABSTRACT TRUNCATED AT 400 WORDS)

5'-Nucleotidase↗

PubMed2002

[Echocardiographic evaluation of left atrial function in dilated cardiomyopathy with restricted and non-restricted Doppler transmitral flow].

UNLABELLED: Left atrial (LA) function is of great importance in left ventricular (LV) filling. There is evidence that echocardiographic Doppler evaluation of transmitral flow, routinely used for LV filling estimation, is dependent on LA function. Information regarding the relation of LA size and function to transmitral flow in heart failure is limited. We used 2D echocardiographic acoustic quantification methods to assess LA function in patients with dilated, (non-ischemic) cardiomyopathy (DCM) and a control group. The DCM group was divided into 2 subgroups: Group 1-with restrictive LV Doppler filling pattern-18 patients (DCM-R) and Group 2-with non-restrictive LV Doppler filling pattern-11 patients (DCM-NR) with similar heart rate, age and degree of mitral regurgitation. LA maximal area, total emptying fraction and absolute and fractional area change during rapid emptying and atrial contraction were calculated. The LA was enlarged only in DCM-R. Both DCM groups had decreased total emptying fractions and rapid emptying area changes compared to controls. An enlarged LA area and more decreased total emptying were found in DCM-R with high LV filling pressures compared to DCM-NR. The restrictive group had a significantly smaller LA rapid emptying area change, as well as a smaller LA area change and emptying fraction during atrial contraction compared to DCM-NR. Within < or = 2 hrs after the echocardiography study, cardiac catheterization was performed in the DCM group. We found significantly higher LV filling pressures and lower LV ejection fractions in DCM-R compared to DCM-NR. Significant correlations were found between LA function and invasive parameters like capillary wedge and LV enddiastolic pressures and LV EF. CONCLUSION: Patients with DCM-R had significantly enlarged LA areas with more depressed total emptying fractions and smaller LA area changes during contraction compared to DCM-NR. Thus, left atrial function plays an important role in LV filling and its dysfunction can be a marker of poor prognosis.

Adult↗

PubMed2003

[Immunological study in sickle cell disease patients: importance of the complement system].

Ten Tunisian patients, with homozygote sickle cell disease and asplenia were studied to investigate and to determine possible immunological function defects. Obtained results directed us to an abnormality of the alternate complement pathway activation which is expressed by a decreased hémolytic activity, while the classic pathway is normal. Quantification of C3, C4, C5, C6, C7 and factor B by immunochemical assay were normal, whereas factor B functional activity was depressed to a mean level of about half of normal in eight patients, IgG was increased in one subject and IgA in two others. Numeration of Band T cells revealed slight decrease in proportion of CD3 and CD4 at one patient associated with an increase in B cells, but normal or increased absolute numbers of all cells population.

Adolescent↗

PubMed2006

Standardization of method for the analysis of dextromethorphan in urine.

Dextromethorphan (DMP), an antitussive, is one of the most popular drugs among the younger generation in Korea. It usually is taken for its hallucinogenic properties and overdoses have been responsible for the fatalities that have been reported frequently. To control the abuse of DMP, the authorities restricted its use through classifying it as a controlled drug on October 2003. The purpose of this study is to provide a standard method for the analysis of DMP and its main metabolite, dextrorphan (DTP) in biological specimens. At first we established a standard operating procedure (SOP) for DMP/DTP in urine, and a method validation was performed. We also quantified DMP from 16 drug abuser's urine samples all of which were positive in the screening test for DMP. For the detection of DMP/DTP, urine samples were adjusted with 6N NaOH (pH 11) and extracted with ethylacetate. Thin layer chromatography was used as the screening test, and the final identification for DMP/DTP was used by GC/MS. The ions (m/z 271 for DMP, m/z 257 for DTP and m/z 86 for lidocaine as internal standard) were extracted from the full scan mass spectrum and were used for quantification. The selectivity, linearity of calibration, accuracy, within- and between day precision, limit of detection and quantification, recovery and stability were examined as parts of the method validation. Extracted calibration curves were linear from 100 to 2000 ng/mL for DMP and DTP with correlation coefficients better than 0.999. Limit detection was 50 ng/mL for DMP and DTP. Within-run precision (%CV) for DMP and DTP at three different concentrations (100, 500 and 1000 ng/mL) was 6.10-18.85%, and between-run precision was 1.70-7.86% for DMP and DTP. Absolute recovery for DMP and DTP was 57-74%, and relative recovery (extraction efficiency) was 80-89%. For 16 drug abuser's urine samples, the concentrations of DMP and DTP were 0.16-52.63 and 0.41-23.75 microg/mL, respectively. Method validation is an important requirement in the practice of chemical analysis, and it will be particularly useful in verifying the reliability of analytical results in the field of forensic science.

Adult↗

PubMed1988

The quantification of cerebral infarction following focal ischemia in the rat: influence of strain, arterial pressure, blood glucose concentration, and age.

Focal cerebral ischemia was induced by occlusion of the middle cerebral artery in rats. The volumetric assessment of infarcted tissue, 2 days following occlusion, was calculated from the examination of eight preselected coronal sections. Five differing rat strains were examined. A small and variable infarcted volume was seen in Wistar-Kyoto rats; Sprague-Dawley rats had a relatively large, but still variable, infarcted volume. Of the normotensive rat strains, the most reproducible volume of infarcted tissue was seen in Fischer-344 rats; also the absolute value of the infarcted volume did not vary from one series to another in this strain. Chronic arterial hypertension, studied in both normal and stroke-prone spontaneously hypertensive rats, was associated with significantly larger infarction volumes. Age does not change the volume of necrosis: Fischer-344 rats were studied at 3, 9, and 20 months of age, and no significant differences were noted between these ages. Experimental diabetes was induced by the administration of streptozotocin 3 days prior to middle cerebral artery occlusion. Severe hyperglycemia (greater than 400 mg/dl) was associated with a considerably increased volume of infarction. The variability of the resultant lesion is high in the most commonly studied strains, but our results suggest that, for studies in normotensive rats, the use of the Fischer-344 strain produces a standardized and repeatable infarction that may be significantly modified by experimental interventions. Age is not a factor that affects the occlusion-induced infarction; in contrast, both chronic arterial hypertension and experimental diabetes aggravate the histological consequences of middle cerebral artery occlusion in the rat. We conclude that quantitative histological evaluation of infarct size allows a meaningful assessment of the gravity of focal cerebral ischemia.

Aging↗

PubMed2004

Coronary artery calcium quantification at multi-detector row helical CT versus electron-beam CT.

PURPOSE: To compare coronary artery calcium scores from a multi-detector row helical computed tomographic (CT) scanner with those from an electron-beam CT scanner, with emphasis on subjects with calcium scores less than 400. MATERIALS AND METHODS: Seventy-eight asymptomatic subjects (37 women, 41 men; age range, 39-78 years; mean age, 54.2 years) underwent multi-detector row CT and electron-beam CT. Volume and Agatston scores were calculated with a workstation. Statistical analyses included assessment of association between calcium scores from two scanners, calculation of percent absolute difference to assess score variability between scanners, equivalence analysis, construction of Bland-Altman plots to assess agreement between scores, and assessment of changes in score grouping and risk criteria based on score differences between scanners. RESULTS: Electron-beam CT calcium scores were higher than multi-detector row CT scores. Linear association between calcium scores obtained from paired scans was significant (r = 0.96-0.99, P <.001). Mean percent absolute differences were 67.9% and 65.0% for volume and Agatston scores, respectively (48.6% and 46.3% for corresponding natural log-transformed scores). In subjects with a score of 11 or greater, mean percent absolute differences between electron-beam CT and multi-detector row CT scores ranged from 15% to 30% (<10% for natural log-transformed calcium scores). With a 20% equivalence limit, calcium scores from the two scanners were statistically equivalent (P <.05). Score grouping would have been subject to change in 12 (11 increased and one decreased; six with scores of 11 or greater), and possible risk management decisions would have been subject to change in eight (16%) of 51 subjects who underwent electron-beam CT versus multi-detector row CT scanning. CONCLUSION: Multi-detector row CT appears to be comparable to electron-beam CT for coronary calcification screening, except in subjects with a calcium score less than 11.

Adult↗

PubMed2003

Haar transform analysis of photon time-of-flight measurements for quantification of optical properties in scattering media.

A method to independently quantify the absorption and the scattering properties of samples based on the analysis of the Haar transform (HT) of photon time-of-flight (TOF) distributions is described. A series of reflectance photon TOF measurements were acquired from absorbing/scattering milk samples of known composition (0 < mu(a) < 0.025 mm(-1); 100 < mu(s) < 250 mm(-1)). The HT of the profiles was calculated, and the regression based on the most parsimonious subset of wavelets was determined by the genetic algorithm (GA). In addition, the utility of computing the logarithm of the profiles or of the absolute value of the wavelet coefficients before the GA was studied. Results show that the absorption coefficient could be estimated with a coefficient of variation (C.V.) of 6.7% and an r2 of 0.99 by use of the log of selected wavelets of frequency less than 800 MHz. Scattering coefficients were estimated with a C.V. of 2.3% and an r2 of 0.99 with the log of wavelets of frequency less than 400 MHz. The above results suggest that a simplified instrument based on low-frequency switches could be developed to quantify the optical properties of highly scattering media.

Animals↗

PubMed2001

NO reburning study based on species quantification obtained by coupling LIF and cavity ring-down spectroscopy.

NO reburning is studied in a low pressure (15 hPa) premixed flame of CH4-O2 seeded with 1.8% of NO. Measurements were carried out by using cavity ring-down spectroscopy (CRDS) and laser induced fluorescence (LIF) techniques. The temperature profile was obtained by OH-LIF thermometry in the A-X (0-0) band. The OH profile was determined by LIF and calibrated by single pass absorption. The NO concentration profile was obtained by LIF in the A-X (0-0) band and corrected for Boltzmann fraction and quantum yield variations. The absolute concentration profile was determined in the burned gases by CRDS allowing a direct experimental determination of the NO reburning amount. Finally CH and CN mole fraction profiles were obtained by CRDS by exciting rotational transitions in the B-X (0-0) bands of CH and CN around 387 nm. We found a peak mole fraction of 29 ppm for CH and 3.3 ppm for CN. This last result is in contrast with a previous study of W. Juchmann, H. Latzel, D. L. Shin, G. Peiter, T. Dreier, H. R. Volpp, J. Wolfrum, R. P. Lindstedt and K. M. Leung, XXVIIth Symposium (International) on Combustion, The Combustion Institute, Pittsburgh, 1998, p. 469, performed in a similar flame, which reported much lower levels of CN. In that study the absolute concentration of CN was indirectly obtained by LIF calibrated by Rayleigh scattering. In a second part, experimental species profiles are compared with predictions of the GRI 3.0 mechanism. Comparison between experimental and predicted profiles shows a good agreement particularly for CN and NO species. A qualitative analysis of NO reburning is then performed.

Journal Article↗

PubMed2002

Automatic determination of brain perfusion index for measurement of cerebral blood flow using spectral analysis and 99mTc-HMPAO.

Cerebral blood flow (CBF) can be non-invasively quantified using the brain perfusion index (BPI), determined from radionuclide angiographic data generated by technetium-99m hexamethylpropylene amine oxime ((99m)Tc-HMPAO). We previously reported the use of a spectral analysis (SA) method using (99m)Tc-HMPAO to calculate the BPI. In this report, we demonstrate an automatic method for determining the optimal BPI value and compare the optimal BPI values with the absolute CBF values measured using H(2)(15)O positron emission tomography (PET). Bilateral cerebral hemispheres of 11 patients with various brain diseases were examined using (99m)Tc-HMPAO. In the automatic SA procedure, the radioactivity curve for the aortic arch ( C (a)) was shifted by 0-10 s. The radioactivity curve for the brain ( C (b)) was estimated using the shifted C (a), and the error value between the actually measured and the estimated C (b) (Err) was calculated. When the Err was at a minimum, the BPI value was defined as optimal BPI. The difference in BPI from the optimal BPI was calculated as |BPI - optimal BPI| / optimal BPIx100 (%). In all participants, an H(2)(15)O PET examination was also performed, and the BPI values were compared with the absolute CBF values measured using H(2)(15)O PET (mCBF(PET)). The difference between BPI and the optimal BPI increased significantly from 4.87%+/-1.69% to 18.38%+/-3.93% (mean+/-SD) when the Err value increased. The optimal BPI value ( y) was well correlated with the mCBF(PET) value ( x) ( y=0.21 x-0.0075, r=0.800). Our results suggest that this automatic SA method provides an accurate estimate of BPI that can be used for the quantification of CBF using (99m)Tc-HMPAO SA.

Brain↗

PubMed2006

Determination of perospirone by liquid chromatography/electrospray mass spectrometry: application to a pharmacokinetic study in healthy Chinese volunteers.

Perospirone is a novel atypical antipsychotic with a unique combination of 5-HT(1A) receptor agonism as well as 5-HT(2A) and D(2) receptor antagonism. A simple rapid and selective LC-MS method utilizing a single quadrupole mass spectrometer was developed and validated for the determination of perospirone hydrochloride in human plasma. N-hexane was used to extract perospirone hydrochloride and amlodipine benzenesulfonate (internal standard (IS)) from an alkaline plasma sample. LC separation was performed on a XTerra MS C(18) column (100mmx2.1mm, i.d. 3.5microm) using methanol -10mM ammonium acetate (84:16, v/v) as a mobile phase. The quantification of target compounds was obtained by using a selected ion monitoring (SIM) at m/z 427.5 [M+H](+) for perospirone hydrochloride, and at m/z 431.4 [M+Na](+) for IS (amlodipine benzenesulfonate). Perospirone and IS eluted as sharp, symmetrical peaks with retention times of 3.11+/-0.01min and 4.15+/-0.2min, respectively. Calibration curves of perospirone hydrochloride in human plasma at concentrations ranging from 0.10 to 21.1ng/mL exhibited excellent linearity (r(2)=0.9997). The mean absolute recovery of the drug from plasma was more than 85%. Intra- and inter-day relative standard deviations were less than 6.43% and 11.9% for perospirone hydrochloride at the range from 0.32 to 10.6ng/mL. Stability characteristics of the drug-containing plasma were thoroughly evaluated to establish appropriate conditions to process, store and prepare for chromatographic analysis without inducing significant chemical degradation. The following pharmacokinetic parameters were elucidated after administering a single dose of 8mg perospirone hydrochloride. The area under the plasma concentration versus time curve from time 0 to 24h (AUC(0-24)) was 15.48+/-4.23microg/Lh; peak plasma concentration (C(max)) was 2.79+/-0.78microg/L; time to C(max) (T(max)) was 1.79+/-0.45h; and elimination half-life (t(1/2)) 6.78+/-1.38h. The described assay method showed acceptable precision, accuracy, linearity, stability, and specificity and can be used for pharmacokinetic studies, therapeutic drug monitoring, and drug abuse screening.

Adult↗

PubMed2002

Determination of melagatran, a novel, direct thrombin inhibitor, in human plasma and urine by liquid chromatography-mass spectrometry.

Analytical methods for the determination of melagatran (H 319/68) in biological samples by liquid chromatography (LC)-positive electrospray ionization mass spectrometry using multiple reaction monitoring are described. Melagatran in plasma was isolated by solid-phase extraction on octylsilica, either in separate extraction tubes or in 96-well plates. Absolute recovery of melagatran from plasma was >92%. Melagatran and the internal standard, H 319/68 D2 13C2, were separated from other sample components by LC utilizing a C18 stationary phase and a mobile phase comprising 35% acetonitrile and 0.08% formic acid in 0.0013 mol/l ammonium acetate solution. After dilution, urine was injected directly onto the LC column and subjected to gradient LC. The relative standard deviation was 1-5% for concentrations above the limit of quantification, which was estimated for plasma at 10 or 25 nmol/l for sample volumes of 500 or 200 microl, respectively, and 100 nmol/l for urine.

Azetidines↗

PubMed2005

Increased cytokine secretion in patients with failed implants compared with patients with primary implants.

All total joint replacements generate wear debris; yet, some implant prostheses fail while others survive despite the presence of ultrahigh molecular weight polyethylene particulate. It was hypothesized that patients with failed hip implants who have osteolysis will secrete higher inflammatory cytokines than patients receiving total joint replacements. Our study evaluated the peripheral blood monocyte response to varying polyethylene particle volume ratios through cytokine quantification in two patient populations: patients having revision surgery for failed total hip replacements (failed implant group) and patients having primary total hip surgery for osteoarthritis of the hip (primary implant group). We observed elevation of all three proinflammatory cytokines tested (interleukin-6, interleukin-1, and tumor necrosis factor-alpha) in response to polyethylene particulate challenge when compared with the controls in both patient groups. The population with failed implants also had a higher absolute cytokine response to polyethylene exposure compared with the control patients having primary implants. These findings suggest that patients with failed implants have a greater inflammatory cytokine response to polyethylene than seen in patients with primary implants.

Arthroplasty, Replacement, Hip↗

PubMed2025

Focus on numbers - characterizing protein accumulation at DNA double-strand breaks.

Unrepaired DNA double-strand breaks can lead to cell death or genomic rearrangements. The DNA damage response (DDR) is a complex signaling cascade in which a plethora of factors act to finely tune repair pathway choice. Several DDR proteins have been shown to accumulate at sites of DNA lesions in characteristic dot-like structures known as DNA repair foci. Changes in foci brightness, commonly expressed in arbitrary intensity units, are often used as readout for DNA repair dynamics. However, due in part to technical challenges, the stoichiometry, absolute number of proteins recruited to DDR foci, and their impact on the resolution of the break remain incompletely characterized. Here, we combine spatial intensity distribution analysis (SpIDA) and a custom foci detection algorithm into an easy-to-use pipeline that, starting from confocal images, allows quantitative description of protein accumulation in DNA repair foci. Moreover, by quantifying foci based on their molecular count, SpIDA overcomes the limitations of ambiguous intensity units, enabling stoichiometric quantification between repair factors and providing a unifying means for experimental comparisons.

DNA Breaks, Double-Stranded↗

PubMed2004

Nonequivalence behavior studies for the direct determination of enantiomeric purity and absolute configuration of timolol by NMR.

Direct determination of both the enantiomeric purity and absolute configuration of timolol was accomplished utilizing 1H NMR (400 MHz) spectroscopy with fast diamagnetic chiral solvating agent to dissimilarly perturb the spectra of enantiomeric solutes. Nonequivalence behavior was studied for all variables that affect populations and intrinsic spectra of the diastereomeric solvates. Optimization of the experimental conditions in terms of probe temperature, substrate concentration and solvating agent to substrate molar equivalents provided resolved enantiomeric signals suitable not only for chiral recognition but also for quantification. Enantiomeric impurity was determined on the basis of relative intensities of the tert-butyl methyl protons resonances; the assignment of enantiomeric configuration was based on the relative field positions of these resonances. The analysis of synthetic mixtures of the enantiomers by the proposed NMR method resulted in assay values which agreed closely with the known quantities of each enantiomer in mixtures tested. The mean +/-SD recovery values for the (R)-(+)-enantiomer was 100.0+/-1.6% of added antipode (n = 8). The optically pure enantiomers were used to establish the minimum detection limits of0.1%. The developed methodology represents a rapid and powerful tool for regulatory analysis.

Adrenergic beta-Antagonists↗

PubMed1995

Hexachlorobenzene treatment increases the number of splenic B-1-like cells and serum autoantibody levels in the rat.

In the present study, the role of B-1 cells in hexachlorobenzene (HCB)-induced autoimmune aberrations in the Wistar rat was investigated. To that end, male and female rats were exposed to a semi-synthetic diet containing 0 or 1000 mg HCB/kg food for 3 weeks. After dissection, serum was prepared form coagulated blood to determine (auto)antibody levels, and spleens and lymph nodes were isolated and weighed. Cell suspensions were prepared, counted and analysed for B- and T-cell subsets by flow cytometry. Quantification of antibody-secreting cells (ASC) in spleen cell suspensions was done with an ELISPOT assay. Previous findings that HCB treatment induced an increase of relative lymph node and spleen weights and serum (auto)antibody levels were confirmed, while it appeared that numbers of some lymph nodal, and of the splenic large cell populations, were elevated as well. HCB treatment did not change subsets of lymph nodal T and B cells, but elevated the absolute numbers of large splenic CD4+ T cells by about 70%, IgMdull/IgDbright B cells by about 60%, and IgMbright/IgDdull B cells by about 200% cells of control numbers, and the absolute numbers of splenic IgM and IgG (auto) ASC by 300-400% of the control numbers. As splenic IgMbright/IgDdull numbers and ASC numbers correlated with statistical significance, the results indicate that HCB treatment selectively activates rat splenic B-1 cells, which may underlie the elevation of serum autoantibody levels.

Animals↗