Functionalization of a GaSe monolayer by vacancy and chemical element doping

The electronic and magnetic properties of the GaSe monolayer can be modified and manipulated through vacancy and chemical element doping.

Periodontitis-specific molecular signatures in gingival crevicular fluid

BACKGROUND AND OBJECTIVE

Periodontitis is currently diagnosed almost entirely on gross clinical manifestations that have been in situ for more than 50 years without significant improvement. The general objective of this study was, therefore, to evaluate whether mid-infrared spectroscopy can be used to identify disease-specific molecular alterations to the overall biochemical profile of tissues and body fluids.

MATERIAL AND METHODS

A total of 190 gingival crevicular fluid samples were obtained from periodontitis (n = 64), gingivitis (n = 61) and normal sites (n = 65). Corresponding infrared absorption spectra of gingival crevicular fluid samples were acquired and processed, and the relative contributions of key functional groups in the infrared spectra were analysed. The qualitative assessment of clinical relevance of these gingival crevicular fluid spectra was interpreted with the multivariate statistical analysis-linear discriminant analysis.

RESULTS

Using infrared spectroscopy, we have been able to identify four molecular signatures (representing vibrations in amide I, amide II/tyrosine rings and symmetric and asymmetric PO2- stretching vibrations of phosphodiester groups in DNA) in the gingival crevicular fluid of subjects with periodontitis or gingivitis and healthy control subjects that clearly demarcate healthy and diseased periodontal tissues. Furthermore, the diagnostic accuracy for distinction between periodontally healthy and periodontitis sites revealed by multivariate classification of gingival crevicular fluid spectra was 98.4% for a training set of samples and 93.1% for a validation set.

CONCLUSION

We have established that mid-infrared spectroscopy can be used to identify periodontitis-specific molecular signatures in gingival crevicular fluid and to confirm clinical diagnoses. Future longitudinal studies will assess whether mid-infrared spectroscopy represents a potential prognostic tool, recognized as key to advancement of periodontics.

Clinical and Experimental Effectiveness of Astragali Compound in the Treatment of Chronic Viral Hepatitis B

Chinese herbs are widely used in the treatment of chronic viral hepatitis B. The effectiveness of 2 months' treatment with Astragali compound (AC), containing Radix Astragali and adjuvant components, was studied for the treatment of chronic viral hepatitis in 116 patients; 92 patients were given other drugs in regular clinical use for viral hepatitis (controls). The clinical efficacy of AC was significantly better in AC-treated patients than in controls. Negative seroconversions of hepatitis B virus (HBV) antigen e and HBV DNA were also significantly higher in AC-treated patients than in controls. Of eight duck viral hepatitis B models infected with duck hepatitis B virus (DHBV) and treated with AC, three showed negative seroconversion of DHBV DNA and serum DHBV DNA levels significantly decreased after AC administration compared with the controls; DHBV DNA was negative in biopsied liver tissue by in situ hybridization and immunohistochemistry in two ducks treated with AC. Pathological changes were milder in AC-treated ducks than in controls. These results indicate that AC may promote recovery from viral hepatitis and inhibit HBV replication.

In vivo determination of multiple indices of periodontal inflammation by optical spectroscopy

BACKGROUND AND OBJECTIVE

Visible, near-infrared (optical) spectroscopy can be used to measure regional tissue hemodynamics and edema and therefore may represent an ideal tool with which to study periodontal inflammation in a noninvasive manner. The study objective was to evaluate the ability of optical spectroscopy to determine simultaneously multiple inflammatory indices (tissue oxygenation, total tissue hemoglobin, deoxyhemoglobin, oxygenated hemoglobin and tissue edema) in periodontal tissues in vivo.

MATERIAL AND METHODS

Spectra were obtained, processed and evaluated from healthy, gingivitis and periodontitis sites (n = 133) using a portable optical, near-infrared spectrometer. A modified Beer-Lambert unmixing model that incorporates a nonparametric scattering loss function was used to determine the relative contribution of each inflammatory component to the overall spectrum.

RESULTS

Optical spectroscopy was harnessed to generate complex inflammatory profiles of periodontal tissues. Tissue oxygenation at periodontitis sites was significantly decreased (p < 0.05) compared to sites with gingivitis and healthy controls. This was largely the result of an increase in deoxyhemoglobin in the periodontitis sites compared with healthy (p < 0.01) and gingivitis (p = 0.05) sites. Tissue water content per se showed no significant difference between the sites, but a water index associated with tissue electrolyte levels and temperature differed significantly between periodontitis sites and both healthy and gingivitis sites (p < 0.03).

CONCLUSION

This study established that optical spectroscopy can simultaneously determine multiple inflammatory indices directly in the periodontal tissues in vivo. Visible, near-infrared spectroscopy has the potential to be developed into a simple, reagent-free, user-friendly, chairside, site-specific, diagnostic and prognostic test for periodontitis.

Quantitative determination of apoptosis on leukemia cells by infrared spectroscopy

Quantitation of apoptotic cell death in vivo has become an important issue for patients with acute leukemia. We describe herein a new analytical method, based on infrared (IR) spectroscopy, to estimate the percentage of apoptotic leukemic cells in two different cell lines (CEM and K562), induced with etoposide (VP-16). As the percentage of apoptosis increases, the protein structure shifts from dominantly beta-sheet to unordered (random coil), the overall lipid content increases and the amount of detectable DNA decreases. These changes can be directly related to the percentage of apoptosis as determined by two standard reference methods: flow cytometry and DNA ladder formation. The correlation between the significant IR spectral changes and the percentage of apoptotic leukemia cells in the two cell lines was optimal up to 24 h following etoposide treatment (r = 0.99 for CEM cells and r = 0.96 for K562 cells). Furthermore, IR spectroscopy is able to detect apoptotic changes in these cells already after 4 h treatment with VP-16, compared to flow cytometry which needs 6 h to observe significant changes. Our study suggests that IR spectroscopy may have potential clinical utility for the early, fast and reagent free assessment of chemotherapeutic efficacy in patients with leukemia.

Comparison of infrared spectroscopic and fluorescence depolarization assays for fetal lung maturity

OBJECTIVE

Infrared spectroscopic analysis of amniotic fluid was recently shown to be a potential useful method for the determination of fetal lung maturity. Those studies used thin-layer chromatography as a reference method for the calibration of the infrared-based technique. However, thin-layer chromatography is compromised by large intra-assay and interlaboratory coefficients of variation. Therefore in this study we have used a reference method that is based on fluorescence depolarization, the TDx FLM II assay, to verify the sensitivity and precision of infrared spectroscopy for assessment of fetal lung maturity status.

STUDY DESIGN

Samples of amniotic fluid were obtained by amniocentesis from 101 patients between the 24th and 40th weeks of pregnancy. Small volumes (35 microL) of amniotic fluid specimens were dried, and the infrared spectra were measured with a commercial infrared spectrometer. The fetal lung surfactant/albumin ratio was determined separately for each specimen with the TDx FLM II assay. The proposed infrared method was then calibrated and tested with a partial least-squares regression analysis to quantitatively correlate the infrared spectra with the surfactant/albumin ratios provided by the TDx FLM II assays.

RESULTS

A total of 144 training spectra were used to build the partial least-squares calibration model. The correlation coefficient for the training set was excellent (r = 0.92), with an SE between infrared-predicted and reference surfactant/albumin ratios of 17 mg/g. The model was then validated on a set of 69 test spectra and yielded an SE of 14 mg/g (r = 0.86). The final partial least-squares model included the 900- to 1500-cm(-1) and 2800- to 3200-cm(-1) spectral ranges and 6 partial least-squares factors.

CONCLUSION

Because the infrared-based fetal lung maturity measurements correlated well with assays from both of the current standard clinical techniques (thin-layer chromatography and fluorescence depolarization) and the procedure is less labor and training intensive, we concluded that infrared spectroscopy has the potential to emerge as the method of choice for prediction of fetal lung maturity from amniotic fluid analysis.

Bryostatin 1-induced modulation of nucleoside transporters and 2-chlorodeoxyadenosine influx in WSU-CLL cells

WSU-CLL cells, a fludarabine resistant B-cell chronic lymphocytic leukemia cell line, has been shown to exhibit enhanced sensitivity to 2-chlorodeoxyadenosine (2-CdA) following 48-72 h exposure to bryostatin 1. For 2-CdA to manifest its chemotherapeutic activity, it must first enter the cell through one of several specific nucleoside transporter systems. We present data to show that bryostatin 1-induced enhanced influx of 2-CdA is in part the result of bryostatin 1-induced modulation of nucleoside transporters in WSU-CLL cells. The bi-directional equilibrative NBMPR sensitive transporters in WSU-CLL cells were significantly down-regulated 90 min post-exposure to 1-200 nM bryostatin 1. This down-regulation was evident up to 144 h. In contrast, WSU-CLL cells exhibited a transient increase in Na+-dependent concentrative 2-CdA influx from 48 to 96 h after bryostatin 1 exposure which was evident for a longer duration than that accounted for by the increase in deocycytidine kinase activity. These data may, in part, explain the enhanced efficacy of 2-CdA seen in WSU-CLL cells following 48-72 h exposure to bryostatin 1. It may raise questions as to the importance of the bi-directional transporters in determining the resistance or sensitivity of CLL cells to 2-CdA or other nucleoside analogues.

Pgp-positive leukaemic cells have increased mtDNA but no increased rate of proliferation

Cells of solid tumours tend to rely on glycolysis for energy. On the other hand, increased glycolysis in solid tumour cells expressing the multidrug resistance protein MDR-1 has been associated with increased malignancy in tumours. We have previously shown that cells of the MDR-1-positive CEM/VLB100 leukaemic cell line have increased mitochondrial electron transport chain (mtETC) activity compared with parental CEM cells. In the present study we used infrared (IR) spectroscopy to demonstrate that the mitochondrial DNA (mtDNA) content in the CEM/VLB100 cell line was significantly increased compared to that in the parental CEM cells. The increase in mtDNA was not accompanied by an increase in mitochondrial protein as both lipid and protein levels were decreased in CEM/VLB100 mitochondria. The ATP content was similar in these two cell lines. However, the ATP-dependent membrane efflux pump function in CEM/VLB100 cells was significantly reduced when mitochondrial ATP synthesis was inhibited by oligomycin, a specific inhibitor of mitochondrial F0F1-ATPase. Proliferation of CEM/VLB100 cells was significantly decreased compared to parental CEM cells, and was independent of p53 expression. Thus, we conclude that: (1) IR spectroscopy is a potential powerful technique for detecting mtDNA, protein and lipid contents simultaneously; (2) leukaemic cells mainly rely on mtDNA for energy; (3) increased expression of an ATP-dependent membrane efflux pump such as Pgp may up-regulate ATP generation and mtDNA content. These metabolic perturbations may exist merely to serve the efflux pump and do not result in an increase in leukaemic cell proliferation. In addition, the associated reduction in mitochondrial lipid and protein may contribute to sensitize the cells to cytochrome c release.

Infrared spectroscopic study of bryostatin 1-induced membrane alterations in a B-CLL cell line

Previous studies on intact cells have shown that bryostatin 1 (Bryo 1) induces significant alterations in the membranes of WSU-CLL cells (a drug-resistant B-CLL cell line), changes which may play an important role in the mechanism of reduced drug resistance of B-CLL cells to 2-chlorodeoxyadenosine (2-CdA). However, it is not clear whether the plasma membranes or the mitochondria, or both are involved; nor is it known which of these two targets is more important for regaining the cells former drug sensitivity. For the present study, we treated WSU-CLL cells with Bryo 1, isolated plasma membranes and mitochondria, and then subjected the purified fractions to infrared (IR) spectroscopic and chromatographic analyses. IR spectroscopy revealed a decreased glycosylation of both plasma membranes and mitochondria in Bryo 1-treated cells compared to untreated cells. The amount of lipid relative to protein was increased in both types of membranes, but considerably more enhanced in the plasma membrane fraction of the Bryo 1-treated cells than in mitochondria. Quantitative lipid analysis by thin layer chromatography also revealed that Bryo 1 treatment significantly increased the phospholipid content in plasma membranes, whereas the lipids in the mitochondria remained essentially unchanged. Changes in lipid composition were quite dramatic for plasma membranes where phosphatidylcholines were decreased by 50%, phosphatidylethanolamines doubled and sphingomyelins increased five-fold compared to the lipid composition in plasma membranes of untreated cells. In addition, the IR spectroscopic analysis provided evidence for an increased plasma membrane fluidity in Bryo 1-treated cells, whereas the fluidity of the mitochondria remained essentially unchanged; marker bands indicating mitochondrial DNA decreased upon Bryo 1 treatment. These results suggest that Bryo 1 increases the sensitivity of WSU-CLL cells to chemotherapeutic agents such as 2-CdA by action on two cell targets: (1) introduction of significant changes in plasma membrane permeability or fluidity through modifications in lipid content and composition as well as by reducing the surface glycosylation; (2) introduction of changes in lipid and DNA content of the mitochondria. Small alterations in the lipid composition of the mitochondria may provide the conditions for an altered proton gradient and transmembrane potential leading to apoptosis and decreased cell survival.

Simultaneous quantitation from infrared spectra of glucose concentrations, lactate concentrations, and lecithin/sphingomyelin ratios in amniotic fluid

OBJECTIVE

The purpose of this study was to assess the feasibility of using infrared spectroscopy to simultaneously predict preterm infection, fetal distress, and fetal lung maturity.

STUDY DESIGN

A total of 189 infrared spectra were acquired from amniotic fluid obtained by amniocentesis. The concentrations of glucose and lactate and the lecithin/sphingomyelin ratios were determined separately by accepted clinical chemistry methods for each sample. Infrared spectra were recorded with a commercial spectrometer and 35 microL amniotic fluid was used for each spectrum. Calibration models (partial least squares) were derived from the correlation between 102 infrared spectra and clinical standard analyses; the model was then validated with the remaining 87 spectra.

RESULTS

By means of the multivariate technique of partial least squares regression, calibration models for glucose and lactate were developed that had excellent correlation coefficients (r = 0.97 for glucose and r = 0. 91 for lactate); the SEs of calibration were 0.04 mmol/L for glucose and 0.09 mmol/L for lactate. The validation sets for the quantitation of glucose and lactate predicted by the calibration models also yielded good outcomes (r = 0.95 for glucose and r = 0.71 for lactate, with SEs of prediction of 0.06 mmol/L and 0.18 mmol/L, respectively).

CONCLUSION

Infrared spectroscopy has the potential to become the clinical method of choice for simultaneously predicting preterm infection, fetal distress, and fetal lung maturity.

Distribution of collagen deposition in cardiomyopathic hamster hearts determined by infrared microscopy

Fibrillar collagens are major proteins of the cardiac extracellular matrix and play a significant role in the structural organization of the healthy heart. The aim of this study was (i) to investigate and compare the patterns of cardiac collagen deposition in different layers taken from both cardiomyopathic and normal myocardium using infrared (IR) microspectroscopy and (ii) to evaluate IR microspectroscopy as an alternative means for in vitro detection of collagen deposition in heart. Frozen sections from UM-X7.1 strain hamsters expressing the cardiomyopathic phenotype associated with ventricular remodeling and age-matched control (F1-beta) strain hamsters were examined using IR microspectroscopy. The presence of collagen was identified by the appearance of a typical collagen band at 1204 cm(-1), and the results were compared with identical tissue sections stained with trichrome, a routine discriminator for interstitial matrix proteins in cardiac myocytes. Spatial information addressing collagen deposition was obtained and viewed using contour mapping and three-dimensional band intensity maps at 1204 cm(-1). Perivascular and interstitial collagen deposition was detected in control samples taken from both ventricles as indicated with relative low intensities of the band of 1204 cm(-1). When compared with these control levels, the concentration of collagen was increased in cardiomyopathic left-ventricular samples with some focal depositions, and these results were confirmed with the trichrome references. Our study suggests that collagen deposition from normal and diseased hearts may be successfully analyzed directly in the absence of any chemihistological or immunological staining, by infrared microscopy.

Prediction of RDS from amniotic fluid analysis: a comparison of the prognostic value of TLC and infra-red spectroscopy

Infra-red (IR) spectroscopy was recently shown to be a sensitive method for the determination of fetal lung maturity (Liu et al., 1998). The present study was undertaken to validate the newly developed method for prediction of RDS (Respiratory Distress Syndrome). Samples of amniotic fluid were obtained by amniocentesis from 86 patients between the 28th and 41st week of pregnancy. A small volume, 35 microliters, of amniotic fluid was used to acquire infra-red spectra with a commercial spectrometer. The lecithin/sphingomyelin (L/S) ratio was determined separately by TLC (thin layer chromatography). A calibration model was established using a partial least squares regression analysis which quantitatively correlated 145 IR spectra with the TLC-based L/S ratios; the correlation coefficient was 0.95. The model was then validated using a total of 111 spectra which also showed a high correlation coefficient (r = 0.91). Based upon the clinical data associated with these samples, the prediction accuracy for the presence of RDS was 67 per cent for TLC and 83.3 per cent for IR. The accuracy for predicting the absence of RDS was 93.4 per cent for TLC and 96.8 per cent for IR. We conclude that IR spectroscopy has the potential to become the clinical method of choice for predicting RDS from amniotic fluid analysis.

In situ infrared histopathology of keratinization in human oral/oropharyngeal squamous cell carcinoma

Fourier transform infrared (FTIR) microspectroscopy is emerging as a promising new tool for histopathological investigations of tissue histochemistry. This study was designed to assess whether changes in tissue biochemistry induced by well-differentiated and poorly differentiated oral/oropharyngeal squamous cell carcinoma (SCC) can be detected by infrared spectroscopy. The biopsies analyzed were each proven SCC positive and compared with tissue taken from the contralateral normal site. Individual infrared spectra, recorded from specific tissue areas, were correlated with histopathological structures normally found in the oral mucosa. Infrared mapping of these areas allows the generation of biochemical images of molecular structures such as lipids, sugars, and proteins. The visualization of DNA and tissue structures containing keratin (well expressed in all epithelia) reveals distinct differences between normal and SCC-positive biopsies. Bivariate histogram analysis of cell components (e.g., DNA and keratin) indicated that cancer cells produce a relatively homogeneous and clearly abnormal cell biochemistry, whereas differentiated epithelial cells present a very heterogeneous distribution of cellular components. Using these features, tissue containing abnormal or cancer cells can easily be distinguished from normal epithelial structures. The abnormal keratin distribution in poorly differentiated SCC and in keratin pearls (present only in well-differentiated SCC) offers insight into the process of malignant tissue transformation in squamous epithelium. Applying infrared microspectroscopy in combination with bivariate statistics to histopathological tissue thin sections provides a potential diagnostic tool for detection of cell changes in epithelial cancers.

Infrared spectroscopic analysis of biomedical specimens using glass substrates

We report on the use of glass substrates for the infrared spectroscopic analysis of dried serum, amniotic fluid, and synovial fluid films. New analytical applications of infrared spectroscopy are emerging rapidly, spurred largely by ever-improving instrumentation, combined with the widespread availability of powerful chemometric methods. We have recently begun to focus upon potential applications in both clinical chemistry and medical diagnostics. For example, serum analysis, the determination of fetal lung maturity, and the differential diagnosis of arthritis have all recently been demonstrated to be feasible on the basis of the infrared spectra of films dried from the appropriate samples (serum, amniotic fluid, or synovial fluid). However, the transition from the laboratory into clinical usage hinges on the availability of IR-transparent substrates that are both inexpensive and readily obtainable. We have demonstrated in this study that despite limited transparency in the IR region, clinical analyses and diagnostic spectral classifications may nevertheless be carried out using glass as a substrate for the IR measurements.

Similarities between the sensitivity to 2-chlorodeoxyadenosine of lymphocytes from CLL patients and bryostatin 1-treated WSU-CLL cells: an infrared spectroscopic study

Infrared (IR) spectroscopy was used to compare the drug resistance mechanism of cells from chronic lymphocytic leukemia (CLL) patients with that of WSU-CLL cells. Bryostatin 1 (Bryo 1), a macrocyclic lactone and protein kinase C activator, was used to render WSU-CLL cells more susceptible to 2-chlorodeoxyadenosine (2-CdA). The IR spectroscopic analysis revealed some changes in protein and DNA content in Bryo 1-treated WSU-CLL cells, however, the most significant alterations were observed in the membrane lipids, which resemble those found between 2-CdA-sensitive and 2-CdA-resistant cells from CLL patients. In addition, Bryo 1 treatment induced WSU-CLL cells to become CD11c, CD25 and tartrate-resistant acid phosphatase-positive, specific markers for hairy cell leukemia, a disease exquisitely sensitive to 2-CdA. Our results suggest that 2-CdA-sensitive CLL cells have cellular characteristics resembling the hairy cell stage. The similarity between the membrane lipids in 2-CdA-sensitive CLL cells and the Bryo 1-treated WSU-CLL cell line supports the suggestion that membrane lipid alteration might be an important step in the drug resistance mechanism of CLL cells.

Sequential treatment of human chronic lymphocytic leukemia with bryostatin 1 followed by 2-chlorodeoxyadenosine: preclinical studies

We have previously reported that bryostation 1 (Bryo 1) induces differentiation of chronic lymphocytic leukemia (CLL) in vitro to a hairy cell (HC) stage. This study tests the hypothesis that Bryo 1-differentiated CLL cells are more susceptible to 2-chlorodeoxyadenosine (2-CdA) than parent CLL cells. A recently established EBV-negative CLL line (WSU-CLL) from a patient resistant to chemotherapy including fludarabine was used to test this hypothesis. Both Bryo 1 (10-1000 nM) and 2-CdA (5.6-22.4 microM) exhibited a dose-dependent growth inhibitory effect on the WSU-CLL cell line. In vitro, the sequential exposure to Bryo 1 (100 nM for 72 h) followed by 2-CdA (11.2 microM) resulted in significantly higher rates of growth inhibition than either agent alone. Changes in immunophenotype, enzymes, lipids, proteins, and the DNA of WSU-CLL cells were studied before and after Bryo 1 treatment. Bryo 1 induced a positive tartrate-resistant acid phosphatase reaction and two important markers, CD11c and CD25, after 72 h of culture, confirming the differentiation of CLL to HC. The Fourier transformation infrared spectroscopic analysis showed that the amount of membrane lipids significantly increased in Bryo 1-treated cells compared to controls after 24 h, whereas the protein content, as well as the DNA content, decreased. This finding supports the change of CLL to HC. To evaluate the in vivo efficacy of Bryo 1 and 2-CdA, we used a xenograft model of CLL in WSU-CLL-bearing mice with severe combined immune deficiency. s.c. tumors were developed by injection of 10(7) WSU-CLL cells, and fragments were then transplanted into a new batch of severe combined immunodeficient mice. Bryo 1 and 2-CdA at the maximum tolerated doses (75 micrograms/kg i.p. and 30 mg/kg s.c., respectively) were administered to the mice at different combinations and schedules. The survival in days, the tumor growth inhibition ratio, the tumor growth delay, and the log10 kill of the mice treated with Bryo 1 followed by 2-CdA were significantly better than the control and other groups. We conclude that the sequential treatment with Bryo 1 followed by 2-CdA resulted in higher antitumor activity and improved animal survival.

Rapid determination of fetal lung maturity from infrared spectra of amniotic fluid

OBJECTIVE

The purpose of this study was to determine the feasibility of infrared spectroscopy as an alternative method for the prediction of fetal lung development.

STUDY DESIGN

Samples of amniotic fluid were obtained by amniocentesis from 134 patients between the 26th and 41st week of pregnancy. To acquire infrared spectra with a commercial spectrometer, 35 microl of amniotic fluid was required for each spectrum. The lecithin/sphingomyelin ratio was determined separately by thin-layer chromatography for each sample. A robust linear discriminant analysis method was used to partition the samples into normal and abnormal groups according to their infrared spectra. A partial least squares regression analysis was then applied to quantitatively correlate the infrared spectra with the thin-layer chromatography-based lecithin/sphingomyelin ratios.

RESULTS

Qualitatively, the infrared spectra of the amniotic fluid in the validation set were successfully partitioned into lecithin/sphingomyelin <2 and lecithin/sphingomyelin >2 groups. Quantitatively, the lecithin/sphingomyelin ratios predicted from the infrared spectra of amniotic fluid were highly correlated and in excellent agreement with those determined by thin-layer chromatography (correlation coefficient = 0.893).

CONCLUSION

Infrared spectroscopy has the potential to become the clinical method of choice for determining fetal lung surfactant maturity in amniotic fluid.

Comparison of infrared spectra of CLL cells with their ex vivo sensitivity (MTT assay) to chlorambucil and cladribine

The drug resistance of leukemic cells from 21 patients with chronic lymphocytic leukemia (CLL) to the alkylating agent chlorambucil (CLB) and the nucleoside analog cladribine or 2-chlorodeoxyadenosine (CdA) was investigated by infrared spectroscopy. Drug sensitivities, determined in vitro with the tetrazolium dye (MTT) assay, were correlated with the infrared spectra of the CLL cells, applying linear discriminant analysis (LDA). The 63 spectra (three from each of the 21 samples), obtained before drug exposure, were successfully partitioned into drug-sensitive and drug-resistant groups; the LDA-based ex vivo prediction of the sensitivity to CdA or CLB was 85.7% and 80.3%, respectively. Similar changes in the composition/structure of DNA were observed between the spectra of the drug-sensitive and drug-resistant CLL cells for both CdA and CLB. However, CdA-resistant CLL cells could also be differentiated from CdA-sensitive CLL cells by spectral changes associated with membrane lipids; these differences were much less pronounced between CLB-resistant and CLB-sensitive CLL cells. We demonstrate here for the first time that infrared spectroscopy can be used as a new tool for predicting ex vivo drug response (sensitivity/resistance).

Prediction of fetal lung maturity from near-infrared spectra of amniotic fluid

OBJECTIVE

The aim of this study was to attempt to correlate the quantitative data obtained from the near-infrared (near-IR) spectra of amniotic fluid with the lecithin/sphingomyelin (L/S) ratio determined from thin layer chromatographic analysis on the same samples, in order to establish the feasibility of near-IR spectroscopy as an alternate method for the prediction of fetal lung development.

METHODS

Samples of amniotic fluid were obtained by amniocentesis from 52 patients between the 26th and 41st week of pregnancy. About 350 microliters of amniotic fluid was required to record the near-IR spectrum over the entire spectral range between 400 and 2500 nm using a commercial spectrometer. The L/S ratio was determined independently by thin layer chromatography (TLC) for each sample. For correlating the infrared spectra with the TLC-based L/S ratios, a partial least squares analysis was used.

RESULTS

The L/S ratios predicted from the near-IR spectra of amniotic fluid were highly correlated and in excellent agreement with those determined by TLC (r = 0.91).

CONCLUSION

Near-IR spectroscopy has the potential to become an alternate method to TLC for prediction of fetal pulmonary maturity.

[Clinical and experimental studies on effects of chronic hepatitis B treated with astragali composita]

Eighty-seven cases of chronic persistent hepatitis (CPH) and 29 cases of chronic active hepatitis (CAH) were treated with Astragali Composita (AC), the clinical markedly effective rates were 69.0% and 55.2%, the total effective rates were 90.8% and 89.7% respectively; the sero-negative conversion rates of HBeAg and HBV-DNA were 27.7% and 28.0% respectively, they were higher than that of control group (P < 0.05-0.01). Eight ducks infected hepatitis B virus were treated with AC, sero-negative conversion of DHBV-DNA was seen in 3 ducks, DHBV-DNA levels of duck sera were lower after treatment than that before treatment (P < 0.05); mild inflammatory changes in liver tissues were seen in 3 ducks, its pathologic changes were milder than that of control groups; DHBV-DNA in liver tissues of 2 ducks was negative in situhybridization. The results indicated that AC had obvious effects of protecting liver tissues and some effects of inhibiting sera HBV and HBV replication.

Five-year follow-up of immune response to hepatitis B vaccine in juveniles

The persistence of anti-HBs was investigated in 95 juveniles who received plasma-derived HBV vaccine (vaccine group) and 63 counterparts who got anti-HBs from natural HBV infection (infection group) for a period of five years. The positive rates of anti-HBs from the first to fifth year in the vaccine group are 97.89%, 98.95%, 81.05%, 78.95% and 72.63% respectively with one recipient remaining anti-HBs negative after being immunized with three dosages of 10 micrograms plasma-derived HBV vaccine in 0, 1st, 2nd month and the mean S/N values (GMV) are 30.94, 22.18, 13.61, 12.02 and 9.18 respectively. There are 26 recipients whose anti-HBs turned from positive to negative at the end of the study with a negative rate of 27.37%. The S/N GMVs in the infection group are 36.37, 27.33, 24.08 at the first, third and fifth year of the study, respectively. Both the S/N GMV and negative rate are lower than that of the vaccine group (P < 0.01). No one was found to have positive HBsAg or elevated ALT in both groups. Questions such as immune dosage, immune program and booster immunization in juvenile population are discussed.

Pregnancy reduces serotonin-induced contraction of guinea pig uterine and carotid arteries

Because platelet activation and serotonin have been implicated in preeclamptic hypertension, we investigated the effect of pregnancy on the contractile response to this agent. Prior studies have shown that the vascular contractions to norepinephrine, angiotensin II, and thromboxane are reduced during normal pregnancy by the altered release of endothelium-derived vasoactive substances. We hypothesized that the contraction to serotonin would also be reduced during pregnancy by an endothelium-dependent mechanism. Isolated ring segments from uterine and carotid arteries of near-term pregnant and nonpregnant guinea pigs were studied after stimulating a small amount of active tone with prostaglandin F2 alpha. Serotonin (10(-8) to 10(-5) M) contractile responses of both arteries were reduced by pregnancy. Regardless of pregnancy status, the contractile responses of the uterine artery to serotonin were severalfold greater than that of the carotid artery whose maximum averaged only 10% of the 120 mM KCl contraction. Denudation of uterine artery abolished acetylcholine-stimulated relaxation in vessels from pregnant and nonpregnant animals. However, serotonin-induced contractions were enhanced by denudation only in ring segments obtained from pregnant animals. Nitric oxide synthase inhibition by either NG-monomethyl-L-arginine (L-NMMA) or N omega-nitro-L-arginine and cyclooxygenase inhibition by indomethacin had no effect on serotonin-induced contraction of intact uterine artery regardless of pregnancy. L-NMMA modestly enhanced the intact carotid arterial response to 10(-5) M serotonin independent of pregnancy.(ABSTRACT TRUNCATED AT 250 WORDS)

Endothelium-derived relaxing factor and indomethacin-sensitive contracting factor alter arterial contractile responses to thromboxane during pregnancy

OBJECTIVES

Pregnancy reduces uterine artery contractile responses to norepinephrine and angiotensin II in many species, including the human and the guinea pig, by release of endothelium-derived relaxing substances. We hypothesized that vascular reactivity to thromboxane during pregnancy would also be reduced by a similar mechanism.

STUDY DESIGN

Isolated ring segments of uterine and carotid arteries from nonpregnant and near-term pregnant guinea pigs were suspended in a myograph for the measurement of isometric tension.

RESULTS

Uterine but not carotid artery sensitivity to cumulative addition of the thromboxane analog U46619 was decreased during pregnancy. The maximal contractile responses of both vessels were unaltered by pregnancy. N omega-nitro-L-arginine (10(-4) mol/L), an inhibitor of nitric oxide endothelium-derived relaxing factor synthesis, increased the sensitivity of uterine and carotid arteries to U46619 in both pregnant and nonpregnant animals. The maximal contractile response of uterine arteries from pregnant guinea pigs was also increased, but that of nonpregnant ones was not. The maximal U46619 contractile response of the carotid artery was not significantly altered by N omega-nitro-L-arginine. Indomethacin (10(-5) mol/L), a cyclooxygenase inhibitor, reduced both the sensitivity and the maximal response of U46619 in each vessel group. Removal of the endothelium from uterine artery of pregnant animals enhanced both sensitivity and maximal response to U46619. Pretreatment of the denuded segments with indomethacin reduced the sensitivity to U46619. However, indomethacin-treated denuded segments were still more sensitive to U46619 than controls.

CONCLUSION

The sensitivity of guinea pig uterine artery but not carotid artery to thromboxane is reduced during pregnancy. Although the precise mechanism remains unclear, both endothelium-derived relaxing factor and an indomethacin-sensitive contracting factor are involved. If indomethacin-sensitive contracting factor is released by humans and disease alters that release, it is possible that any enhanced contractile response to thromboxane resulting from the loss of endothelium-derived relaxing agents such as prostacyclin and endothelium-derived relaxing factor would be offset by the loss of indomethacin-sensitive contracting factor.

Oxidative status of lipoproteins in coronary disease patients

Oxidized low-density lipoprotein (LDL) may play an important role in atherogenesis. The oxidative status of isolated LDL and very low-density lipoprotein (VLDL) were investigated in 23 patients with proven coronary disease and in 23 healthy asymptomatic control subjects. Oxidized cholesterol (4-cholesten-3-one and 20 alpha-OH cholesterol) was identified in LDL and VLDL from both groups. The content of cholesterol and 4-cholesten-3-one in LDL from patients was significantly increased in comparison with values from the control subjects. Lipid peroxidation, as assessed by malondialdehyde (MDA) formation, was barely detectable in native LDL and VLDL from the two groups. However, after incubation with a free radical-producing system, MDA levels in LDL from patients were significantly higher than those in control subjects. Lysine reactivity in LDL after incubation with an oxidizing agent, CuSO4, was similar between groups. However, lysine reactivity to CuSO4 in VLDL from patients was less than that in control subjects. Our results suggest that LDL levels from patients with coronary disease have an elevated oxidized cholesterol content and are more susceptible to peroxidative modification. Conversely, the LDL apoprotein does not appear to have been oxidatively modified in these patients. The data are consistent with a role for oxidized LDL in coronary artery disease and indicate that the LDL lipid may be an important oxidation site.

Effects of cholesterol oxidase on cultured vascular smooth muscle cells

Cholesterol oxidase (3 beta-hydroxy-steroid oxidase) catalyzes the oxidation of cholesterol to 4-cholesten-3 one and other oxidized cholesterol derivatives. The purpose of the present study was to investigate its effects on cultured vascular smooth muscle cells. Cultured rabbit aortic smooth muscle cells were morphologically altered after exposure to cholesterol oxidase in the presence of culture medium containing 10% fetal calf serum. If fetal calf serum was absent, cells were unaffected by the treatment. The extent of morphological change of the smooth muscle cells was dependent upon the time of exposure to the enzyme and the concentration of cholesterol oxidase employed. After moderate treatment with cholesterol oxidase, cells excluded trypan blue. Further, a specific mitochondrial marker DASPMI (dimethyl aminostyryl-methyl-pyridiniumiodine) which was used as a fluorescent index of cell viability, revealed that cell viability was unchanged after moderate cholesterol oxidase treatment. Nile red, a hydrophobic probe which selectively stains intracellular lipid droplets, was applied to detect the cellular lipid content after treatment with cholesterol oxidase. Cellular nile red fluorescence intensity increased linearly with the time and concentration of cholesterol oxidase treatment. These results demonstrate that cholesterol oxidase alters lipid deposition in the cell and changes cell morphology. The primary site of action of cholesterol oxidase appears to be independent of the cell membrane itself and instead is dependent upon the lipid content in the surrounding culture media. These changes occur prior to the cytotoxic effects of extensive oxidation. Because oxidized cholesterol may play an important role in the pathogenesis of atherosclerosis, our results have implications for intracellular accumulation of lipids in smooth muscle cells during the atherosclerotic lesion.

Effects of oxidative modification of cholesterol in isolated low density lipoproteins on cultured smooth muscle cells

It has been proposed that low density lipoprotein (LDL) must undergo oxidative modification before it can participate in atherosclerosis. The present paper studied the effect of cholesterol oxidation in LDL on cultured vascular smooth muscle cells. LDL was oxidized by cholesterol oxidase (3-beta-hydroxy-steroid oxidase) which catalyzes the oxidation of cholesterol to 4-cholesten-3 one and other oxidized cholesterol derivatives. Cholesterol oxidase treatment of LDL did not result in lipid peroxidation. Cultured rabbit aortic smooth muscle cells were morphologically changed following exposure to cholesterol oxidized LDL. Nile red, a hydrophobic probe which can selectively stain intracellular lipid droplets, was applied to detect the cellular lipid content after treatment with oxidized or non-oxidized LDL cholesterol. LDL which did not undergo oxidation of its cholesterol had no effect on the cells. However, cellular nile red fluorescence intensity was increased as the pre-incubation time of cholesterol oxidase with LDL increased. This was supported by HPLC analysis which revealed that the oxidized cholesterol content of treated cells increased. These findings suggest that cholesterol oxidation of LDL can alter lipid deposition in the cells and change cell morphology. The oxidation of cholesterol in vivo may play an important role in the modification of LDL which could contribute to the generation of the lipid-laden foam cells.

Effect of pregnancy on endothelium and smooth muscle: their role in reduced adrenergic sensitivity

During pregnancy, vascular reactivity of the uterine artery is characterized by decreased contraction to norepinephrine and increased relaxation to acetylcholine. We investigated whether 1) relaxation to A23187 is increased during pregnancy and 2) endothelium-derived relaxing factor (EDRF) and/or prostaglandins are responsible for the decreased uterine artery sensitivity to norepinephrine during pregnancy. Isolated rings of uterine and carotid arteries were obtained from pregnant and nonpregnant guinea pigs. Relaxation to sodium nitroprusside in uterine but not carotid artery was reduced during pregnancy. Relaxation of both uterine and carotid arteries to the calcium ionophore A23187 was unaffected by pregnancy. During pregnancy, contractions to norepinephrine were reduced in the uterine artery compared with arteries from nonpregnant animals. Indomethacin slightly enhanced the contractions of uterine artery to norepinephrine during pregnancy. However, indomethacin-treated uterine arteries from pregnant animals were still less responsive to norepinephrine than control uterine arteries from nonpregnant animals. Methylene blue enhanced the efficacy of norepinephrine in uterine arteries of nonpregnant animals as well as carotid arteries of pregnant and nonpregnant animals but not in uterine arteries of pregnant animals. In contrast, N-monomethyl-L-arginine, a specific inhibitor of EDRF synthesis, not only enhanced uterine and carotid artery responses to norepinephrine in both pregnant and nonpregnant animals but fully reversed the blunted potency of norepinephrine on uterine arteries of pregnant to that of nonpregnant animals.(ABSTRACT TRUNCATED AT 250 WORDS)

[A preliminary study on response to hepatitis B vaccine in subjects with various levels of antibody to hepatitis B surface antigen]

After hepatitis B vaccine immunization, serum antibody response was of primary type in 33 cases with anti-HBs less than 2.1 S/N (S/N Ratio Unit) at T0, the anti-HBs positive rate was 39.4%, 84.8%, 96.7% and 96.7% in T1, T2, T0 and T12 respectively. Anti-HBs S/N rose gradually month by month, the antibody response in younger children was better than that in adult. Anamnestic type in 38 cases with anti-HBs greater than 2.1 S/N at T0, the antibody levels rose rapidly in T1, T2 and began to fall in T8. The children were negative for HBsAg, anti-HBs and anti-HBc in sera by RPHA, PHA and ELISA respectively, most (100% in 1-4 age group and 63.2% in 5-9 age group) of them were also negative for HBV serological markers by SPRIA repeatedly, thus they were susceptible and need for hepatitis B vaccine immunization. Indication of hepatitis B vaccination for adult population was also discussed.