Determination of Pralsetinib in Human Plasma and Cerebrospinal Fluid for Therapeutic Drug Monitoring by Ultra-performance Liquid Chromatography-Tandem Mass Spectrometry (UPLC-MS/MS)

BACKGROUND

Ultra-performance Liquid Chromatography-tandem Mass Spectrometry (UPLC-MS/MS) is widely used for concentration detection of many Tyrosine Kinase Inhibitors (TKIs), including afatinib, crizotinib, and osimertinib. In order to analyze whether pralsetinib takes effect in Rearranged during Transfection (RET)-positive patients with central nervous system metastasis, we aimed to develop a method for the detection of pralsetinib concentrations in human plasma and Cerebrospinal Fluid (CSF) by UPLC-MS/MS.

METHODS

The method was developed using the external standard method, and method validation included precision, accuracy, stability, extraction recovery, and matrix effect. Working solutions were all obtained based on stock solutions of pralsetinib of 1mg/mL. The plasma/CSF samples were precipitated by acetonitrile for protein precipitation and then separated on an ACQUITY UPLC HSS T3 column (2.1×100 mm, 1.8 µm) with a gradient elution using 0.1% formic acid (solution A) and acetonitrile (solution B) as mobile phases at a flow rate of 0.4 mL/min. The tandem mass spectrometry was performed by a triple quadrupole linear ion trap mass spectrometry system (QTRAPTM 6500+) with an electrospray ion (ESI) source and Analyst 1.7.2 data acquisition system. Data were collected in Multiple Reaction Monitoring (MRM) and positive ionization mode.

RESULTS

A good linear relationship of pralsetinib in both plasma and CSF was successfully established, and the calibration ranges were found to be 1.0-64.0 µg/mL and 50.0ng/mL-12.8 µg/mL for pralsetinib in the plasma and CSF, respectively. Validation was performed, including calibration assessment, selectivity, precision, accuracy, matrix effect, extraction recovery, and stability, and all results have been found to be acceptable. The method has been successfully applied to pralsetinib concentration detection in a clinical sample, and the concentrations have been found to be 475ng/mL and 61.55 µg/mL in the CSF and plasma, respectively.

CONCLUSION

We have developed a quick and effective method for concentration detection in both plasma and CSF, and it can be applied for drug monitoring in clinical practice. The method can also provide a reference for further optimization.

Age-, sex- and proximal-distal-resolved multi-omics identifies regulators of intestinal aging in non-human primates

The incidence of intestinal diseases increases with age, yet the mechanisms governing gut aging and its link to diseases, such as colorectal cancer (CRC), remain elusive. In this study, while considering age, sex and proximal-distal variations, we used a multi-omics approach in non-human primates (Macaca fascicularis) to shed light on the heterogeneity of intestinal aging and identify potential regulators of gut aging. We explored the roles of several regulators, including those from tryptophan metabolism, in intestinal function and lifespan in Caenorhabditis elegans. Suggesting conservation of region specificity, tryptophan metabolism via the kynurenine and serotonin (5-HT) pathways varied between the proximal and distal colon, and, using a mouse colitis model, we observed that distal colitis was more sensitive to 5-HT treatment. Additionally, using proteomics analysis of human CRC samples, we identified links between gut aging and CRC, with high HPX levels predicting poor prognosis in older patients with CRC. Together, this work provides potential targets for preventing gut aging and associated diseases.

Multi-MSIProcessor: Data Visualizing and Analysis Software for Spatial Metabolomics Research

Mass spectrometry imaging (MSI) has emerged as a revolutionary analytical strategy in biomedical research for molecular visualization. By linking the characterization of functional metabolites with tissue architecture, it is now possible to reveal unknown biological functions of tissues. However, due to the complexity and high dimensionality of MSI data, mining bioinformatics-related peaks from batch MSI data sets and achieving complete spatially resolved metabolomics analysis remain a great challenge. Here, we propose novel MSI data processing software, Multi-MSIProcessor (MMP), which integrates the data read-in, MSI visualization, processed data preservation, and biomarker discovery functions. The MMP focuses on the AFADESI-MSI data platform but also supports mzXML and imzmL data input formats for compatibility with data generated by other MSI platforms such as MALDI/SIMS-MSI. MMP enables deep mining of batch MSI data and has flexible adaptability with the source code opened that welcomes new functions and personalized analysis strategies. Using multiple clinical biosamples with complex heterogeneity, we demonstrated that MMP can rapidly establish complete MSI analysis workflows, assess batch sample data quality, screen and annotate differential MS peaks, and obtain abnormal metabolic pathways. MMP provides a novel platform for spatial metabolomics analysis of multiple samples that could meet the diverse analysis requirements of scholars.

Time-Course Lipidomics of Ornithine-Induced Severe Acute Pancreatitis Model Reveals the Free Fatty Acids Centered Lipids Dysregulation Characteristics

The relationship between the type and intensities of lipids of blood and pancreas and the pathological changes in the pancreas during severe acute pancreatitis (SAP) remains unclear. In our study, we employed a rat model of SAP induced through intraperitoneal ornithine injections. We collected serum and pancreas samples at various time points (0-144 h) for histopathological and biochemical assessments, followed by lipidomic analyses using LC-MS/MS or in situ mass spectrometry imaging (MSI) To discern changes over time or at specific points, we employed time-course and univariate analyses for lipid screening, respectively. Our findings indicated that the peak inflammation in the Orn-SAP model occurred within the 24-30 h timeframe, with evident necrosis emerging from 24 h onwards, followed by regeneration starting at 48 h. Time-course analysis revealed an overall decrease in glycerophospholipids (PEs, PCs, LPEs, LPCs), while CEs exhibited an increase within the pancreas. Univariate analysis unveiled a significant reduction in serum TAGs containing 46-51 carbon atoms at 24 h, and CERs in the pancreas significantly increased at 30 h, compared with 0 h. Moreover, a substantial rise in TAGs containing 56-58 carbon atoms was observed at 144 h, both in serum and pancreas. MSI demonstrated the CERs containing saturated mono-acyl chains of 16 and 18 carbon atoms influenced pancreatic regeneration. Tracing the origin of FFAs hydrolyzed from pancreatic glycerophospholipids and serum TAGs during the early stages of inflammation, as well as FFAs utilized for CEs and CERs synthesis during the repair phase, may yield valuable strategies for diagnosing and managing SAP.

Novel Isotope-Labeled Derivatization Strategy for the Simultaneous Analysis of Fatty Acids and Fatty Alcohols and Its Application in Idiopathic Inflammatory Myopathies and Pancreatic Cancer

Fatty acids (FAs) and fatty alcohols (FOHs) are essential compounds for maintaining life. Due to the inherent poor ionization efficiency, low abundance, and complex matrix effect, such metabolites are challenging to precisely quantify and explore deeply. In this study, a pair of novel isotope derivatization reagents known as d0/d5-1-(2-oxo-2-(piperazin-1-yl) ethyl) pyridine-1-ium (d0/d5-OPEPI) were designed and synthesized, and an in-depth screening strategy for FAs and FOHs was established based on d0/d5-OPEPI coupled with liquid chromatography-tandem high-resolution mass spectrometry (LC-HRMS/MS). Using this approach, a total of 332 metabolites were identified and annotated (some of the FAs and FOHs were reconfirmed by standards). Our results demonstrated that OPEPI labeling could significantly enhance the MS response of FAs and FOHs via the introduction of permanently charged tags. The detection sensitivities of FAs were increased by 200-2345-fold compared with the nonderivatization method. At the same time, for FOHs, due to the absence of ionizable functional groups, sensitive detection was achieved utilizing OPEPI derivatization. One-to-one internal standards were provided by using d5-OPEPI labeling to minimize the errors in quantitation. Moreover, the method validation results showed that the method was stable and reliable. Finally, the established method was successfully applied to the study of the FA and FOH profiles of two heterogeneous severe clinical disease tissues. This study would improve our understanding of the pathological and metabolic mechanisms of FAs and FOHs for inflammatory myopathies and pancreatic cancer and also prove the generality and accuracy of the developed analytical method for complex samples.

UPLC-MS/MS method development and application to pharmacokinetic study in rats and dogs of Flonoltinib Maleat

Flonoltinib Maleate (FM) is a novel selective inhibitor of Janus kinase 2/FMS-like tyrosine kinase 3 (JAK2/FLT3). In this study, we developed an ultra-high-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) method to measure the plasma concentrations of FM in rats and dogs for pharmacokinetic studies. For chromatographic separation, we used a BEH C18 column (2.1 × 50 mm, 1.7 μm particle size) in HPLC. The mobile phase A consisted of a water solution containing 0.1% formic acid (FA) and 2 mM NH₄OAc, mixed with acetonitrile (ACN) (V:V = 95:5). The mobile phase B was a water solution containing 0.1% FA and 2 mM NH₄OAc, mixed with ACN (V:V = 5:95), which was used for gradient elution. We used multiple reactive ion detection (MRM) mode and electrospray ionization positive (ESI+) mode for quantitative analysis. The standard curve was linear in the concentration range of 0.5 to 500 ng/ml in rat and dog plasma. The intra-batch and inter-batch precision (RSD%) of FM in rat and dog plasma was less than 15%. The intra-batch and inter-batch accuracy was 88.3-106.5% and 92.0-100.6% in rats, and 94.7-106.6% and 95.3-103.8% in dogs, respectively. The RSD (%) of matrix factors (MF) normalized to the internal standard (IS) of FM in rat and dog plasma was ≤5.6% and ≤3.0%, respectively. The extraction recovery and carryover were considered acceptable. When the sample concentration was higher than the upper limit of quantitation (ULOQ), the 10-fold dilution was reliable within the limits of acceptability. The UPLC-MS/MS method developed in this study was successfully applied in measuring the pharmacokinetic parameters of FM in rats and dogs after intravenous and oral administration, laying a foundation for the preclinical pharmacokinetic study of FM and providing a reference for clinical pharmacokinetic studies.

Temporal Proteomic and Lipidomic Profiles of Cerulein-Induced Acute Pancreatitis Reveal Novel Insights for Metabolic Alterations in the Disease Pathogenesis

The pathophysiological mechanisms of acute pancreatitis (AP) are complex and have remained a mystery to date, but metabolism is gradually recognized as an important driver of AP onset and development. We used a cerulein-induced AP mouse model to conduct liquid chromatography-mass spectrometry (LC-MS/MS)-based time-course proteomics and lipidomics in order to better understand the underlying metabolic alterations linked with AP. Results showed that a series of significant changes in proteins over time with a boost in expression were enriched in lipase activity, lipoprotein, and lipids absorption and transport regulation. Furthermore, 16 proteins associated with lipid metabolism and signaling pathways together with the whole lipid species changing profile led to the vital identification of changing law in glycerides, phosphoglycerides, and free fatty acids. In addition to lipid metabolism and regulation-associated proteins, several digestive enzymes and adaptive anti-trypsin, stress response, and energy metabolism-related proteins showed an increment in abundance. Notably, central carbon and branched chain amino acid metabolism were enhanced during 0-24 h from the first cerulein stimulation. Taken together, this integrated proteomics and lipidomics revealed a novel metabolic insight into metabolites transforming rules that might be relevant to their function and drug targets investigation. (Created with Biorender.com.).

Temporal metabolic trajectory analyzed by LC-MS/MS based targeted metabolomics in acute pancreatitis pathogenesis and Chaiqin Chengqi decoction therapy

BACKGROUND

Acute pancreatitis (AP) is an inflammatory disorder of pancreas that lacks effective specific drugs as well as gold standard laboratory tests for diagnosis and severity assessment. Chaiqin chengqi decoction (CQCQD) has been proven to alleviate the severity and mortality of AP, but its underlying mechanisms remain incompletely understood.

PURPOSE

To investigate the correlation between metabolic trajectories of the serum and pancreas, the metabolic pathways with respect to the onset and progression of AP, and investigate the effect of CQCQD in modulating the dysregulated pancreatic metabolism of AP.

METHODS

Serum and pancreas samples from cerulein-induced AP mice were collected for pathology, biochemical index assessment, LC-MS/MS based metabolomics and functional validation over the course of 1 - 24 h. The temporal trends of pancreatic and serum metabolites in AP were analyzed using Mfuzz clustering algorithm, and their associations were revealed by Pearson correlation analysis. The metabolic trajectories and pathways across multi-timepoints were analyzed by univariate and multivariate statistical analyses, and the AP-related metabolic pathways were further screened by metabolite correlation and network interaction analyses. Finally, the changes in metabolite levels and metabolic trajectory after CQCQD therapy were identified, and the altered expression of related metabolic enzymes was verified by RT-qPCR, western blotting, and immunohistochemistry.

RESULTS

Amino acid metabolism was significantly altered in the pancreas and serum of AP, but with different trends. The unsynchronized "open" and "closed" metabolic trajectories in pancreas and serumrevealed that metabolic processes occur earlier in peripheral rather than local tissue, with the most obvious changes occuring at 12 h in the pancreas which were also consistent with the inflammation score results. Several amino acid intermediates showed strong positive correlation between serum and pancreas, and therein serum cystathionine was positively correlated to 33 pancreatic metabolites. In particular, the correlations between the levels of pancreatic cystathionine and methionine, serine, and glutathione (GSH) emphasized the importance of trans-sulfuration to GSH metabolism for AP progression. CQCQD treatment reversed the metabolic trajectory of the pancreas, and also restored the levels of cystathionine and glutathione synthase.

CONCLUSION

Our results have defined a unique time-course metabolic trajectory for AP progression in both the serum and pancreas; it has also revealed a key role of CQCQD in reversing AP-associated metabolic alterations, thus providing new metabolic targets for the treatment and prognosis of AP.

[Emulation pulmonary nodules localization model:a novel non-invasive localization technique in resection of pulmonary nodules]

Objective: To explore the accuracy and efficiency of a novel 3D-printed emulation localization model of small pulmonary nodules in lung surgery. Methods: From April 2020 to April 2021, a total of 66 patients were selected in the study, who underwent localization and resection of pulmonary nodules with video-assisted thoracoscopic surgery (VATS) guided by the 3D-printed emulation localization model at Department of Thoracic Surgery, West China Hospital of Sichuan University. There were 13 males and 53 females, aged from 25 to 79 (52.7±11.4) years. Of all patients, 24 (36.4%) had single pulmonary nodule, and 42 (63.6%) had synchronous multiple pulmonary nodules. The chest high-resolution CT image data were utilized for digital reconstruction and 3D printing to make a tailored life-size emulation pulmonary nodules localization model, which was used to navigate real-time intraoperative localization of nodules. Clinical data including operative parameters, localization information, resection types and pathological findings of nodules were analyzed. The pulmonary nodules that doctors planned to resect were categorized into two categories:major nodules and additional nodules, according to their presence of invasion and radiological risk factors. The accuracy of localization and resection efficiency of nodules were evaluated in accordance with the categories of the nodules respectively. Results: On the basis of preoperative evaluation, there were 71 major nodules with median maximal diameter of 0.9 (0.6-1.3) cm, and 77 additional nodules with median maximal diameter of 0.5 (0.4-0.7) cm. All patients underwent VATS surgery, 52 of them (78.8%) were treated with uniportal VATS and 14 (21.2%) with triportal VATS. Among the patients with single nodule, 18 segmentectomies and 6 wedge resections were performed; whereas among the patients with multiple nodules, 5 segmentectomies, 14 wedge resections, and 23 combined pulmonary resections (including 2 cases of lobectomy+segmentectomy, 7 cases of lobectomy+wedge resections, and 14 cases of segmentectomy+wedge resections) were achieved. The median operative time was 93 (45-240) min, and the median resection time for all nodules was 51.4 (6.7-147.0) min. All major nodules were successfully resected and visibly dissected after removal, and all additional nodules were successfully resected with 85.7%(66/77) nodules visibly dissected. The accuracy rate of localization of both types of nodules was 100%. All major nodules were malignant, and the malignancy rate of additional nodules was 21.2%(14/66). Conclusion: This novel 3D-printed emulation localization model of small pulmonary nodules proved to be a non-invasive, accurate and efficient technique. Not only that, it has a unique advantage in localization of synchronous multiple pulmonary nodules.

HMPA-Catalyzed One-Pot Multistep Hydrogenation Method for the Synthesis of 1,2,3-Trisubstituted Indolines

A convenient and facile method was developed for the synthesis of 1,2,3-trisubstituted indolines. Starting from indole derivatives and ketones/aldehydes, the corresponding indoline products could be obtained with high yield by the hexamethylphosphoramide (HMPA) catalyzed indole Friedel–Crafts reaction, reduction and direct reductive amination process.

[Strategies for the prevention and control of bleeding due to vascular injury in thoracoscopic lung surgery]

The technique of thoracoscopic lung surgery has gradually matured. Nowadays, thoracoscope is recommended as the most preferred approach for surgical treatment of early stage non-small cell lung cancer in different guidelines. However, there are still some cases of accidential major bleeding due to vascular injury during thoracoscopic lung surgery. The wall of the hilum vessels is relatively thin. These vessels often involve a great portion of the cardiac output blood flow. Once the injury happened, the emergent condition may be life-threatening due to massive blood loss. Therefore, this became an important factor which hindered the development of thoracoscopic lung surgery. In this review, details of the vascular injury in thoracoscopic lung surgery were summarized, including the incidence of vascular injury, commonly injured sites and reasons of the injuries. Among all the cases of thoracoscopic major pulmonary resection, 2.9% to 9.2% may suffer from vascular injury during the operation. The most commonly injuried sites are pulmonary artery and the branches, and this is also the most critical situation during thoracoscopic lung surgery. Hilum adhesion is the most important risk factor for vascular injury. On the one hand, the suction-compressing angiorrhaphy technique was developed for bleeding control and angioplasty. On the other hand, the strategies like pre-control of the pulmonary, cut the bronchus in advance, and fire the bronchus and pulmonary artery together may decrease the incidence of vascular injury in patients with risk factors.

HBV-induced ROS accumulation promotes hepatocarcinogenesis through Snail-mediated epigenetic silencing of SOCS3

Interleukin-6 (IL-6) has been demonstrated to be involved in Hepatitis B virus (HBV)-associated hepatocarcinogenesis through activation of the STAT3 pathway. The sustained activation of the IL-6/STAT3 pathway is frequently associated with repression of SOCS3, which is both a target gene and a negative regulator of STAT3. However, the silencing mechanism of SOCS3 in hepatocellular carcinoma (HCC) remains to be elucidated. Here, we showed that the repression of SOCS3 and sustained activation of IL-6/STAT3 pathway in HBV-producing HCC cells were caused by HBV-induced mitochondrial ROS accumulation. Mechanistic studies revealed that ROS-mediated DNA methylation resulted in the silencing of SOCS3. Decreased SOCS3 expression significantly promoted the proliferation of HCC cells and growth of tumor xenografts in mice. Further studies revealed that HBV-induced ROS accumulation upregulated the expression of the transcription factor, Snail, which bound to the E-boxes of SOCS3 promoter and mediated the epigenetic silencing of SOCS3 in association with DNMT1 and HDAC1. In addition, we found that the expression of Snail and SOCS3 were inversely correlated in HBV-associated HCC patients, suggesting that SOCS3 and/or Snail could be used as prognostic markers in HCC pathogenesis. Taken together, our data show that HBV-induced mitochondrial ROS production represses SOCS3 expression through Snail-mediated epigenetic silencing, leading to the sustained activation of IL-6/STAT3 pathway and ultimately contributing to hepatocarcinogenesis.

Minimally invasive surgery for congenital diaphragmatic hernia: a meta-analysis

Objectives

To compare the safety and efficacy of minimally invasive surgery (MIS) with traditional open surgical approach for congenital diaphragmatic hernia (CDH).

Methods

A literature search was performed using the PubMed database, Embase, and the Cochrane central register of controlled trials using a defined set of criteria. The outcomes, which include post-operative mortality, incidence of hernia recurrence, rates of patch use and complications, were analyzed.

Results

We investigated nine studies, which included 507 patients. All studies were non-randomized historical control trials. The MIS group had a significantly lower rate of post-operative death with a risk ratio of 0.26 [95 % confidence interval (CI) 0.10–0.68; p = 0.006] but a greater incidence of hernia recurrence with a risk ratio of 3.42 (95 % CI 1.98–5.88; p < 0.00001). Rates of prosthetic patch use were similar between the two groups. Fewer cases of surgical complications were found in the MIS group with a risk ratio of 0.66 (95 % CI 0.47–0.94; p = 0.02).

Conclusions

MIS for CDH repair is associated with lower post-operative mortality and morbidity compared with traditional open repair. Although rate of patch use appears to be comparable, the increased risk of CDH recurrence should not be ignored. The lack of well-controlled prospective trials still limits strong evaluations of the two surgical techniques.

Occipital somites guide motor axons of the accessory nerve in the avian embryo

The accessory nerve (nervus accessorius) displays a unique organization in that its axons ascend along the rostrocaudal axis after exiting the cervical spinal cord and medulla oblongata and thereafter project ventrally into the periphery at the first somite level. Little is known about how this organization is achieved. We have investigated the role of somites in the guidance of motor axons of the accessory nerve using heterotopic transplantations of somites in avian embryos. The formation of not only accessory nerve but also the vagal nerve was affected, when a more caudal occipital somite (somites 2-4) was grafted to the position of the first occipital somite. Our study reveals that only the first occipital somite permits the development of ventral projection of accessory axons, a process that is inhibited by more caudal occipital somites.

Simultaneous operation of concomitant diseases in the esophagus and lung

The aim of this study was to retrospectively review our experience of performing simultaneous operations on concomitant diseases in the esophagus and lungs. From January 1998 to July 2009, simultaneous operations were performed on 13 patients with concomitant esophageal and pulmonary diseases, using coordinated surgical approaches. Among the 13 patients, six had primary cancers in the esophagus and lungs, five had primary esophageal cancer accompanied by a benign pulmonary disease, one had benign diseases in both esophagus and lung, and one had primary esophageal cancer with metastasis to the left lower lung. All patients survived the operations. Two major complications occurred postoperatively. One complication was bronchopleural fistula and the other was intrathoracic gastric laceration. Both patients recovered after additional treatments. Simultaneous operation of concomitant diseases in the esophagus and lungs is feasible and safe in selected patients who have received careful preoperative assessment, well-designed surgical approach, and proper perioperative management.

Skin biopsies demonstrate MPZ splicing abnormalities in Charcot-Marie-Tooth neuropathy 1B

OBJECTIVE

To demonstrate that intronic mutations in the myelin protein zero (MPZ) cause Charcot-Marie-Tooth neuropathy 1B (CMT1B) by disrupting MPZ splicing.

METHODS

We report a family with a T>G transversion at the invariant + 2 position in intron 4 of MPZ (c.614 + 2T>G) that abolishes 5' donor site recognition and is predicted to alter MPZ splicing. We obtained detailed clinical and neurophysiologic analysis of the family. We performed skin biopsies to investigate splicing abnormalities, MPZ protein levels, and localization in myelinated nerves.

RESULTS

Patients developed a late onset neuropathy with minimally slow nerve conduction velocities. Skin biopsies confirmed the predicted skipping of exon 4 and downstream frameshift of the mutant MPZ. Quantitative immuno-EM demonstrated normal nerve MPZ levels, suggesting that the mutant MPZ was transported to compact myelin.

CONCLUSIONS

Intronic mutations cause CMT1B by disrupting splicing and certain MPZ mutations may cause neuropathy by interacting with the wild type MPZ in the extracellular space of compact myelin.

[Bone-inducing activity of human bone morphogenetic protein-2 102 peptide]

To analyze the bone-inducing activity of C terminal of hBMP-2 and get a new recombinant product of hBMP-2, the gene encoding 102 aa of hBMP-2 mature peptide C terminal was cloned and expressed in E. coli and the first Cys was mutated with Ser. The fragments encoding the target peptide were amplified and cloned into heat-inducible expression vector pDH and transformed into E. coli DH5 alpha. After induction, a new protein bond appeared on the SDS-PAGE. The expressed products amounted to 30% of the total bacterial protein, which existed in the form of inclusion body. The products of bacterial lysates were purified through the ion-exchange chromatography. The denatured proteins were dialysed and diluted directly into the refolding buffer. The renatured products were implanted into mouse thigh muscles to analyze their bone-inducing activity respectively. The results of histological assay showed that the 102 peptide of hBMP-2 could ectopically induce formation of bone, while the mutated 102 peptide of hBMP-2 could not. It suggested hBMP-2 102 peptide still had bone-inducing activity. The first Cys of hBMP-2 mature peptide might be necessary for integrity of three pairs of disulfide bond, and also essential for bone-inducing activity of hBMP-2.

Effect of ACE/NEP inhibition on cardiac and vascular collagen in stroke-prone spontaneously hypertensive rats

Left ventricular remodeling in hypertension is associated with cardiac interstitial and perivascular collagen deposition. The dual angiotensin I converting enzyme/neutral endopeptidase inhibitor omapatrilat (also called vasopeptidase inhibitor) improves left ventricular remodeling in experimental heart failure. We hypothesized that omapatrilat would induce regression of cardiac and vascular fibrosis in hypertension. We, therefore, investigated the effect of omapatrilat on collagen deposition in heart and aorta of stroke-prone spontaneously hypertensive rats (SHRSP). Twenty-week-old normotensive Wistar-Kyoto (WKY) rats, untreated SHRSP, and SHRSP treated with omapatrilat (40 mg/kg per day, orally) for 10 weeks were investigated. Collagen in the heart and the descending thoracic aorta was stained with Sirius red. After 10 weeks, systolic blood pressure (BP) was significantly (P < .01) reduced in omapatrilat-treated versus untreated SHRSP. Interstitial collagen density was significantly decreased in the subendocardial myocardium (to 2.71 +/- 0.24% v 4.12 +/- 0.30%, respectively, P < .05) and in the midmyocardium of omapatrilat-treated versus untreated SHRSP (to 3.01 +/- 0.25 v 4.19 +/- 0.17% respectively, P < .05). Perivascular collagen was significantly (P < .05) decreased in the subepicardial, mid-myocardial and, subendocardial regions of the myocardium of omapatrilat-treated versus untreated SHRSP. Aortic collagen content decreased in omapatrilat-treated versus untreated SHRSP (to 36.1 +/- 2.8 v 58.8 +/- 6.1 x 10(3) microm2/mm section, respectively, P < .05). In conclusion, in addition to being a potent antihypertensive agent, omapatrilat significantly improves cardiac and vascular fibrosis in SHRSP.

Beneficial effect of glycoprotein IIb/IIIa inhibitor (AZ-1) on endothelium in Escherichia coli endotoxin-induced shock

OBJECTIVE

To investigate the effects of AZ-1, a murine monoclonal antiglycoprotein-IIb/IIIa antibody, on endothelium and on hemostasis in a rabbit endotoxic shock model.

DESIGN

Prospective laboratory study.

SETTING

University laboratory.

SUBJECTS

Thirty-five male New-Zealand rabbits.

INTERVENTIONS

In vitro vascular reactivity, endothelium CD31-PECAM1 immunohistochemistry, plasma coagulation factors, and monocyte tissue factor determination were performed 1 day and/or 5 days after onset of endotoxic shock (0.5 mg/kg, intravenous bolus,Escherichia coli lipopolysaccharide) with or without treatment by AZ-1 (0.5 mg/kg intravenously) given 1 hr after lipopolysaccharide injection.

MEASUREMENTS AND MAIN RESULTS

Metabolic acidosis and coagulation activation confirmed the presence of shock. AZ-1 treatment improved endothelial-dependent relaxation at 1 day (maximal effect = 87.2 +/- 4.0% vs. 60.9 +/- 5.2% in the nontreated group, p <.05) and at 5 days (maximal effect = 84.5 +/- 3.5% vs. 56.6 +/- 8.2% in the nontreated group, p <.05). Endotoxin-induced endothelial injury was decreased significantly by AZ-1 at 1 day (6.4 +/- 1.9% vs. 10.3 +/- 0.8% in the nontreated group, p <.05) and at 5 days (6.3 +/- 2.0% vs. 20.2 +/- 1.2% in the nontreated group, p <.05). Monocyte tissue factor expression was significantly reduced at 5 days.

CONCLUSIONS

These data indicate that potent inhibition of platelet function via antiglycoprotein-IIb/IIIa receptor blockade can inhibit coagulation activation and protect against endothelial dysfunction and histologic injury in endotoxin-induced shock.

[Construction of human bone morphogenetic protein-2 expressing eukaryotic vector]

OBJECTIVE

To construct human bone morphogenetic protein-2(hBMP-2) expressing eukaryotic vector and observe whether it can be expressed in eukaryotic cells.

METHODS

pUC19 was digested with Sal I and Xba I. The resulting Sal I-Xba I fragment (1.24 kb) which contains the full length of human BMP-2 cDNA was separated on agarose gel and ligated into eukaryotic expression vector pcDNA3 digested with XhoI and XbaI. The recombinant pcDNA3-hBMP-2 plasmid was transferred into fibroblasts cell line NIH3T3. The stable expression of hBMP-2 in the positive cells G418 selected was determined by in situ hybridization and immunohistochemical analysis.

RESULTS

The two fragments digested from recombinant pcDNA3-hBMP-2 plasmid by EcoR I and Xba I represented 1.3 kb and 5.38 kb respectively by agarose electrophoresis, meanwhile the Xho I site was disappeared in pcDNA3-hBMP-2 indicating the successful construction of recombinant pcDNA3-hBMP-2 plasmid. Stable expression of hBMP-2 in pcDNA3-hBMP-2 transfected cells was confirmed by in situ hybridization and immunohistochemical analysis.

CONCLUSION

hBMP-2 expressing eukaryotic vector is successfully constructed and can be expressed in eukaryonic cells.

Effect of L-arginine on endothelial injury and hemostasis in rabbit endotoxin shock

To investigate whether impaired endothelial function was related to alteration of nitric oxide (NO) formation during endotoxic shock, we studied the effects of supplementation of L-arginine (L-Arg), D-arginine (D-Arg), and N(G)-nitro-L-arginine methyl ester (L-NAME), on endothelial function and structure in a rabbit model. Endotoxic shock was induced by a single lipopolysaccharide bolus (0.5 mg/kg i.v., Escherichia coli endotoxin). Coagulation factors and expression of monocyte tissue factor were determined by functional assays. Endothelium-dependent vascular relaxation was assessed by in vitro vascular reactivity. Immunohistochemical staining (CD31) was performed to assess damaged endothelial cell surface of the abdominal aorta. These parameters were studied 5 days after the onset of endotoxic shock and were compared under three conditions: in absence of treatment, with L-Arg or D-Arg supplementation, or with L-NAME. Both L-Arg and D-Arg significantly improved endothelium-dependent relaxation and endothelial morphological injury. L-NAME did not alter endothelial histological injury induced by lipopolysaccharide. These data indicate that arginine supplementation nonspecifically prevents endothelial dysfunction and histological injury in rabbit endotoxic shock. Moreover, L-Arg has no effect on coagulation activation and expression of monocyte tissue factor induced by endotoxic shock.

A single endotoxin injection in the rabbit causes prolonged blood vessel dysfunction and a procoagulant state

OBJECTIVES

To determine the duration of vascular blood vessel dysfunction and coagulation abnormalities after administration of endotoxin in a nonlethal septic rabbit model.

DESIGN

Randomized, controlled, interventional trial.

SETTING

University animal laboratory.

SUBJECTS

A total of 30 male New Zealand White rabbits, randomly assigned to one of two groups.

INTERVENTIONS

Male New Zealand White rabbits were randomly divided into control or lipopolysaccharide (LPS) (0.5 mg/kg iv bolus Escherichia coli endotoxin)-treated groups. Metabolic acidosis and coagulation activation confirmed the presence of septic shock. The abdominal aorta was removed at 24 hrs (day 1), day 5, or day 21 after LPS injection. Immunohistochemical staining for an endothelial cell marker (PECAM-1/CD31) was performed to assess endothelial injury. Endothelium-dependent vascular relaxation was analyzed by in vitro vascular reactivity studies. Responses to acetylcholine, to calcium ionophore (A-23187), and to sodium nitroprusside were studied. In addition, arterial blood samples were collected on day 1, day 5, and day 21 for measurement of clotting factors and tissue factor activity.

MEASUREMENTS AND MAIN RESULTS

LPS injection resulted in endothelial injury, with loss of approximately 25% of the endothelial area on day 5, which disappeared on day 21. LPS injection also caused a significantly reduced relaxation response to acetylcholine (44.9% +/-9.9% vs. 76.5%+/-5.4% for the control group; p < .005), which was restored on day 21. In contrast, vascular relaxation in response to A-23187 and sodium nitroprusside was not altered. A significant decrease in the platelet count was observed on day 1, associated with a decrease in factors II and V. On day 5, platelet count and factors II and V were corrected in conjunction with an elevated monocyte tissue factor activity in LPS-injected rabbits. On day 21, coagulation abnormalities were corrected.

CONCLUSIONS

A single endotoxin injection in the rabbit was responsible for prolonged aortic endothelial cell dysfunction, as well as a prolonged procoagulant state. The latter is a potential trigger for disseminated intravascular coagulation. Importantly, these features are associated with normalization of conventional biological evidence of septic shock.

Expression, purification, and bone-inducing activity of recombinant human bone morphogenetic protein-3 mature peptide

It was inferred that the mature peptide of human bone morphogenetic protein-3 (hBMP-3m) consists of the carboxyl terminal 127 amino acid residues of hBMP-3. A plasmid, pDH-B3m, was constructed by inserting the cDNA sequences encoding hBMP-3m into pDH, a PL-containing expression vector. pDH-B3m was transformed into Escherichia coli DH5 alpha. The highest expression level of recombinant hBMP-3m (rhBMP-3m) could be reached after 6 hours of induction at 42 degrees C, accounting for 28% of the total bacterial proteins. The rhBMP-3m was found in the inclusion bodies. After being washed and partially purified, the inclusion bodies were solubilized in urea and purified efficiently through ion-exchange chromatography. The purity of the rhBMP-3m was at least 95%. The rhBMP-3m was refolded by dilution method and then 1 mg was implanted into mouse thigh muscle to assay its activity. A classic pattern of cartilaginous osteogenesis was observed. The results showed that the purified and refolded rhBMP-3m had ectopic bone-inducing activity.

Increase in endogenous brain superoxide dismutase as a potential mechanism of lipopolysaccharide-induced brain ischemic tolerance

A low dose (0.5 mg/kg) of lipopolysaccharide (LPS), administered 72 hours before 60-minute middle cerebral artery occlusion, induced a delayed neuroprotection proven by the significant decrease (-35%) of brain infarct volume in comparison with control, whereas infarct volumes remained unchanged in rats treated 12, 24, or 168 hours before ischemia. This delayed neuroprotective effect of LPS was induced only with low doses (0.25 to 1 mg/kg), whereas this effect disappeared with a higher dose (2 mg/kg). The delayed neuroprotection of LPS was induced in the cortical part of the infarcted zone, not in the subcortical part. The beneficial effect of LPS on consequences of middle cerebral artery occlusion was suppressed by dexamethasone (3 mg/kg) and indomethacin (3 mg/ kg) administered 1 hour before LPS, whereas both drugs had no direct effect on infarct volume by themselves, suggesting that activation of inflammatory pathway is involved in the development of LPS-induced brain ischemic tolerance. Preadministration of cycloheximide, an inhibitor of protein synthesis, also blocked LPS-induced brain ischemic tolerance suggesting that a protein synthesis is also necessary as a mediating mechanism. Superoxide dismutase (SOD) could be one of the synthesized proteins because lipopolysaccharide increased SOD brain activity 72 hours, but not 12 hours, after its administration, which paralleled the development of brain ischemic tolerance. In contrast, catalase brain activity remained unchanged after LPS administration. The LPS-induced delayed increase in SOD brain content was suppressed by a previous administration of indomethacin. These data suggest that the delayed neuroprotective effect of low doses of LPS is mediated by an increased synthesis of brain SOD that could be triggered by activation of inflammatory pathway.

Alkylator resistance in human B lymphoid cell lines: (1). Melphalan accumulation, cytotoxicity, interstrand-DNA-crosslinks, cell cycle analysis, and glutathione content in the melphalan-sensitive B-lymphocytic cell line (WIL2) and in the melphalan-resistant B-CLL cell line (WSU-CLL)

Two human B lymphoid cell lines WIL2 (melphalan sensitive. ***IC50:8.57 +/- 1.08 mM) and WSU-CLL (melphalan resistant, ***IC50:223.18 +/- 6.45 mM) were used as models to study alkylator resistance in human lymphoid cells. Melphalan transport studies demonstrated decreased initial melphalan accumulation in WSU-CLL cells as compared to WIL2 cells. Lineweaver-Burk plots of the rate of initial melphalan uptake showed an approximately 3.5-fold decrease of Vmax in WSU-CLL cells as compared to WIL2 cells. Melphalan transport was inhibited by 2-amino-bicyclo[2,2,1] heptane-2-carboxylic acid(BCH) in both cell lines, indicating that the amino acid transport (System L, which is sodium independent and inhibited by BCH) is functional in these two cell lines. Only a minor degree of inhibition of melphalan transport was noted after sodium depletion (System ASC, which is sodium dependent and unaffected by BCH). Interstrand-DNA-cross-link formation showed a highly significant correlation with in-vitro cytotoxicity in both two cell lines. However, the melphalan concentration at which such interstrand DNA cross-linking occurred differed significantly when WIL2 cells and WSU-CLL cells were compared. The kinetics of interstrand-DNA-cross-link formation and removal following treatment with melphalan also differed significantly, with WSU-CLL cells, showing a much more rapid rate of removal of interstand DNA cross-links as compared to WIL2 cells. Cell cycle analysis showed that melphalan treatment resulted in the progressive arrest of the WSU cells in G1 and G2 phases. But WIL2 cells failed to enter G1 or G2 arrest after melphalan treatment, suggesting an increased rate of DNA repair occurring in melphalan-resistant WSU-CLL cells. There was no significant difference between the two cell lines in regard to either glutathione content or glutathione-S transferase activity. These findings indicate that multiple factors are associated with alkylator resistance in lymphoid cells including alteration of uptake, DNA repair and cell cycle progression. However no evidence for alteration in glutathione content and glutathione-S-transferase activity was found.

Susceptibility to provoked cerebral infarction is not increased in a rat model of pharmacologically-induced hypertension despite endothelial dysfunction

An increase in susceptibility to provoked stroke has been described in a genetically-determined rat model of hypertension. We investigated whether the susceptibility to provoked cerebral ischaemia was also increased in a rat model of pharmacologically-induced hypertension with endothelial dysfunction. Chronic inhibition of nitric oxide synthase induced by N(omega)-nitro-L-arginine methyl ester (L-NAME) administration (50 or 75 mg.kg(-1) x day(-1)) in drinking water for 6 weeks caused a sustained hypertension, comparable in the two groups. Endothelium-dependent relaxation induced by acetylcholine or A23187 was significantly, and dose-dependently, impaired in rats receiving L-NAME, as proven by a decrease in maximal relaxation and increase of EC50, as compared to control. Endothelium-independent relaxation induced by sodium nitroprusside was not different in the three groups. Aortic media area was significantly, and dose-dependently, increased following chronic nitric oxide inhibition. Cerebral infarct volumes were not increased in L-NAME-treated groups independently of the level of endothelial dysfunction induced by chronic L-NAME administration. These data demonstrate that susceptibility to cerebral infarction was not increased in a non-genetically determined hypertension model in spite of the development of endothelial dysfunction and vascular structure alterations.

Differential role of nitric oxide pathway and heat shock protein in preconditioning and lipopolysaccharide-induced brain ischemic tolerance

The purposes of this study were to investigate the role of nitric oxide (NO), nitric oxide synthase (NOS), and 70 kDa heat shock protein in brain ischemic tolerance induced by ischemic preconditioning and lipopolysaccharide. Focal cerebral ischemia was induced in rats by intraluminal middle cerebral artery occlusion. Infarct volume was significantly reduced (1) in rats subjected to 3 min ischemia 72 h prior to 60 min ischemia; (2) in rats administered lipopolysaccharide (0.5 mg/kg; i.p.) 72 h prior to 60 min ischemia compared with controls. The beneficial effect of ischemic preconditioning was unchanged despite prior administration of nitro-L-arginine methyl ester (L-NAME), a NOS inhibitor. Conversely, the protective effect of lipopolysaccharide was nullified by L-NAME. Using immunohistochemical techniques, we observed that (1) ischemic preconditioning but not lipopolysaccharide induces the expression of 70 kDa heat shock protein in cerebral cortex and (2) lipopolysaccharide induces early increased expression of endothelial NOS in cerebral blood vessels. The results suggest that (1) endothelium-derived NO plays a role of a trigger in the brain tolerance induced by lipopolysaccharide, and (2) 70 kDa heat shock protein is involved in the protection afforded by ischemic preconditioning but not by lipopolysaccharide.

Relationship between inward rectifier potassium current impairment and brain injury after cerebral ischemia/reperfusion

Functional alterations of barium-sensitive potassium inward rectifier (KIR) current, which is involved in the vasodilation of middle cerebral arteries (MCA) in rat brain, have been described during brain ischemia/reperfusion (I/R). The authors investigate the effects of I/R on KIR current recorded in isolated myocytes from MCA of control rats and from contralateral and ipsilateral MCA of ischemic rats by the whole-cell patch-clamp technique, and the relationship between its alteration and the severity of brain injury. The vascular smooth muscle cells exhibited similar morphologic features in all conditions, and the KIR was present in the three groups of myocytes, exhibiting a characteristic inward rectification and a normal external potassium dependence. The KIR density was significantly reduced in cell of MCA ipsilateral to occlusion with a maximum at -135 mV, whereas there was no difference between control and contralateral cells. This alteration in KIR density in occluded MCA was significantly correlated with severity of brain injury and brain edema. These results suggest that the alteration of KIR density in MCA myocytes after I/R and the consecutive impaired dilation of MCA may contribute to aggravation of the brain injury.

Production of human recombinant bone morphogenetic protein-2A by high density culture of Escherichia coli with stationary dissolved oxygen fed-batch condition

The optimization of cultivation condition in 500 ml shake flasks was carried out to produce recombinant human bone morphogenetic protein-2A (BMP-2A) in recombinant Escherichia coli YK537/pDH-B2m, followed by a 5L fermenter batch and condition-controlled fed-batch culture to obtain BMP-2A. The comparison of these two methods indicated that cultivation by keeping dissolved oxygen at 30%-40% and limiting glucose concentration could obtain BMP-2A 2.78 g/L broth, the final cell density was OD600 53 (dry cell weight 21.2 g/L), and expressed BMP-2A was 25% of the total amount of protein in E.coli. The critical fermentation conditions included: (1) keeping appropriate dissolved oxygen concentration in the process; (2) limiting glucose concentration; (3) taking heat induction at the middle-log phase and maintaining 42 degrees C for 4 hours; (4) controlling specific growth rate around 0.3 h-1 in the duration of growth.

Low dose of lipopolysaccharide induces a delayed enhanced nitric oxide-mediated relaxation in rat aorta

Delayed effect on vascular reactivity of isolated aorta was studied after injection of a single low dose of lipopolysaccharide (0.5 mg/kg i.p.). The maximal vascular effect was observed 72 h after lipopolysaccharide administration with an increase in maximal endothelium-dependent relaxing response to acetylcholine and parallelly a decrease in contractile response to phenylephrine. The change in contractile response was nullified by endothelium removal as well by in vitro aortic rings incubation with N(omega)-monomethyl-L-arginine but not with indomethacin. A low dose of lipopolysaccharide induces a delayed enhanced nitric oxide-mediated vascular relaxation which could contribute to its delayed anti-ischemic properties in ischemic tolerance phenomenon.

[Effects of calcium overload in the conversion of acute edematous pancreatitis to necrotizing pancreatitis in rats]

OBJECTIVE

To investigate the potential of pancreatic acinar cell calcium overload in the conversion of acute edematous pancreatitis (AEP) to necrotizing pancreatitis (ANP).

METHODS

Ninety-six Sprague-Dawley rats were randomized in three experimental groups. Sham-operated control (Group I) AEP (Group II) was induced by pancreatic duct ligation and intravenous injection of bombesin (100 micrograms/kg) and secretin (10 micrograms/kg). ANP (Group III) was induced same as group II but with a large dose of dextran 110,000(500 mg/kg) intravenously. Pancreatic acinar cell Ca2+ overload was studied using fluorescent probe Fura2. Cytosolic free Ca2+ concentration ([Ca2+]i) in isolated pancreatic acinar cells and Ca(2+)-ATPase activity in pancreatic cell plasma membranes were determined 1, 3, 6, 9 h respectively after treatment.

RESULTS

The results showed that pancreatic acinar cell [Ca2+]i was elevated at 1 h[(213 +/- 19) nmol/L, P < 0.05] and increased to (464 +/- 29) nmol/L at 6 h(P < 0.05) in rats with ANP, pancreatic cell plasma membrane Ca(2+)-ATPase activity decreased significantly from (29.8 +/- 0.4) nmol.min-1.mgp-1 at 1 h to (18.6 +/- 0.5) nmol.min-1.mgp-1 at 9 h in rats with ANP (P < 0.05).

CONCLUSIONS

In ischemia-induced conversion of AEP to ANP, there exists Ca2+ overload in the pancreatic acinar cells. The decreased pancreatic cell plasma membrane Ca(2+)-ATPase activity may be an important reason for acinar cell Ca2+ overload in the development of acute pancreatitis.

Conformal episcleral plaque therapy

PURPOSE

Episcleral plaque therapy (EPT) with sealed 125I sources is widely used in the treatment of choroidal melanoma. In EPT, as elsewhere in radiotherapy, concern for normal tissue tolerance has frequently been a dose-limiting factor. The concept of conformal therapy, which seeks to improve dose homogeneity within the tumor and greatly reduce the dose to uninvolved structures may provide a solution to this problem. Radioactive sources are typically distributed uniformly over the surface of an episcleral plaque and are sometimes offset slightly from the scleral surface to reduce the dose to the sclera relative to the apex and prescribed therapeutic margin at the tumor base. Nevertheless, it is not uncommon for scleral dose to exceed the dose to the apex of intermediate to tall tumors by a factor of 4 or more. The availability of low-energy sealed sources such as 125I prompted the development of gold-backed plaques to shield noninvolved periocular tissues. The concept of shielding can be extended to include collimation of individual sources. The potential advantages of individual source collimation include reduced scleral dose, more homogeneous tumor dose, and superior shielding of adjacent normal structures such as the fovea as compared to previous plaque designs.

METHODS AND MATERIALS

A three-dimensional treatment-planning system has been extended to design a plaque that incorporates individually collimated 125I sources. Thermoluminescent dosimetry (TLD) and radiochromic film were used to compare calculated dose-rate distributions with measured dose rates in an acrylic phantom.

RESULTS

Calculations predict that source collimation in the form of a "slotted" gold plaque will achieve the purposes of the study. The collimating effect of the slots is demonstrated qualitatively using radiochromic film, and the accuracy of the calculation is demonstrated quantitatively with TLD.

CONCLUSION

The episcleral plaque described in this report is simpler to assemble than previous plaque designs. It produces a more homogeneous dose distribution in the tumor, reduces scleral dose by up to 50% as compared to conventional designs, and significantly reduces radiation dose to uninvolved structures adjacent to the plaque.

Effect of lignocaine in myocardial contusion: an experiment on rabbit isolated heart

1. The reported incidence of myocardial contusion after blunt chest trauma varies from 16 to 76%. Of these patients, about 6% present a severe, life threatening contusion. We used an isolated heart preparation to examine the effect of lignocaine on myocardial performance after contusion. 2. Thirty hearts obtained from male New Zealand rabbits were perfused at constant flow according to the Langendorff technique and were divided into four groups. The following parameters were measured at frequent intervals for 60 min: mean coronary perfusion pressure (CPP), left ventricular diastolic pressure (LVDP), developed pressure (DP), dP/dtmax, dP/dtmin. 3. Group 1 (n = 6) served as control, group 2 (n = 7) received lignocaine for 20 min (15 microM for the first 10 min and 30 microM for the following 10 min), group 3 (n = 9) had a contusion leading to a 30-50% decrease in dP/dtmax and group 4 (n = 8) had the contusion and the lignocaine infusion was started 10 min after the contusion and stopped after 30 min. Lignocaine concentration was measured in the effluent. 4. Lignocaine alone moderately decreased contractility in group 2. In group 3, after contusion, DP, dP/ dtmax, and dP/dtmin were markedly decreased during the 60 min recording period. In group 4, lignocaine infusion rapidly restored contractility. DP, dP/dtmax and dP/dtmin returned towards their basal values. This improvement of contractility remained stable, even after lignocaine infusion was discontinued. 5. In our rabbit isolated heart preparation, lignocaine at a low therapeutic concentration was able to restore contractility after contusion. These results need to be confirmed by other studies but this may lead to promising therapeutic intervention.

Enhancement of radiosensitivity in human malignant glioma cells by hypericin in vitro

Hypericin, an antidepressant and antiviral agent being evaluated in phase I and II trials for patients with HIV infection, is known to be a potent protein kinase C inhibitor. We have investigated its effects on cellular response to radiation via a tetrazolium-formazan cell growth rate assay using 3-(4,5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide and clonogenic assay in three human glioblastoma cell lines, U87-MG, A-172, and T98G, and a low-passage malignant glioma culture, 93-492. At a concentration of 5 microM, hypericin inhibited these cells slightly but caused significant radiosensitization (e.g., the cell survival rate after the radiation treatment was 50.2 and 26.0% in cells treated with 6 Gy and 6 Gy plus 5 microM hypericin in U87-MG cells, respectively; P = 0.0285). Hypericin also enhanced the radiosensitivity significantly in the low-passage glioma 93-492 cells. These findings suggest that hypericin represents a potential new agent in combination with radiation therapy of malignant gliomas.

Structure-activity relationships of N6-benzyladenosine-5'-uronamides as A3-selective adenosine agonists

Adenosine analogues modified at the 5'-position as uronamides and/or as N6-benzyl derivatives were synthesized. These derivatives were examined for affinity in radioligand binding assays at the newly discovered rat brain A3 adenosine receptor and at rat brain A1 and A2a receptors. 5'-Uronamide substituents favored A3 selectivity in the order N-methyl > N-ethyl approximately unsubstituted carboxamide > N-cyclopropyl. 5'-(N-Methylcarboxamido)-N6-benzyladenosine was 37-56-fold more selective for A3 receptors. Potency at A3 receptors was enhanced upon substitution of the benzyl substituent with nitro and other groups. 5'-N-Methyluronamides and N6-(3-substituted-benzyl)adenosines are optimal for potency and selectivity at A3 receptors. A series of 3-(halobenzyl)-5'-N-ethyluronamide derivatives showed the order of potency at A1 and A2a receptors of I approximately Br > Cl > F. At A3 receptors the 3-F derivative was weaker than the other halo derivatives. 5'-N-Methyl-N6-(3-iodobenzyl)adenosine displayed a Ki value of 1.1 nM at A3 receptors and selectivity versus A1 and A2a receptors of 50-fold. A series of methoxybenzyl derivatives showed that a 4-methoxy group best favored A3 selectivity. A 4-sulfobenzyl derivative was a specific ligand at A3 receptors of moderate potency. An aryl amino derivative was prepared as a probe for radioiodination and receptor cross-linking.

[Isolation and identification of a strain of Pseudomonas SP. producing insoluble glucan hydrolase]

A strain, CIB871, isolated from the natural world can hydrolyze insoluble glucan(IG) produced by S. mutans. This organism has been identified to be a strain of Pseudomonas SP. It grows well at 30 degrees C. The optimum medium for producing insoluble glucan hydrolase (IGase) is composed of 0.3% peptone, 0.03% IG and M1 salt solution (NH4)2 SO4 1mg/ml, MgSO4 50 micrograms/ml, FeCl2 50 micrograms/ml, K2HPO4 0.5mg/ml). The IGase production reached maximum when cultured for 65-70 hours.

[A histopathological study of bone marrow in acute myeloid leukemia. Bone marrow biopsy changes before chemotherapy and comparison with bone marrow smears]

Histopathological changes of pretreatment bone marrow biopsy from 42 cases with acute myeloid leukemia (AML) were described. A considerable difference was shown between the results of aspirate smears and the findings of plastic embedded biopsy sections, particularly in bone marrow cellularity such as infiltration of inflammatory cells and presence of residual hemopoietic cells, qualitative and quantitative abnormalities of megakaryocytes suggestive of myelodysplastic features were more accurately assessed in the sections of marrow biopsy than in the aspirate smears. In three cases there was considerable infiltration of maturing but dysplastic granulocytic cells and erythroid precursors in the sections, but not in the aspirate smears. Our study shows that plastic embedded biopsy sections provide more information than aspiration smears for the diagnosis of AML.

[A histopathological study of bone marrow following chemotherapy of acute myeloid leukemia]

The findings of serial observation on 128 bone marrow biopsies following the completion of remission-induction chemotherapy from 12 patients with acute myeloid leukemia (AML), suggest that chemotherapy gave rise to various histologic changes, including hypoplasia, oedematous marrow stroma with widely dilated sinuses and large unilocular fat cells, ('structured fat') developed from multilocular preadipocyte. Early regenerating hemopoietic foci of erythroid, granulocytic and megakaryocytic cells were almost exclusively in the areas of structured fat. Our data showed that fat cells may play an important role in hemopoietic regeneration. and that chemotherapy does not eradicate leukemic cells even in those cases with clinically complete remission. If biopsy specimen showed abnormal localization of immature precursors, (ALIP) It would indicate that complete remission is not reached. and the Patients must receive consolidation chemotherapy until 'ALIP' clusters disappear.