Rice GA3ox1 modulates pollen starch granule accumulation and pollen wall development

The rice GA biosynthetic gene OsGA3ox1 has been proposed to regulate pollen development through the gametophytic manner, but cellular characterization of its mutant pollen is lacking. In this study, three heterozygotic biallelic variants, "-3/-19", "-3/-2" and "-3/-10", each containing one null and one 3bp-deletion allele, were obtained by the CRISPR/Cas9 technique for the functional study of OsGA3ox1. The three homozygotes, "-19/-19", "-2/-2" and "-10/-10", derived from heterozygotic variants, did not affect the development of most vegetative and floral organs but showed a significant reduction in seed-setting rate and in pollen viability. Anatomic characterizations of these mutated osga3ox1 pollens revealed defects in starch granule accumulation and pollen wall development. Additional molecular characterization suggests that abnormal pollen development in the osga3ox1 mutants might be linked to the regulation of transcription factors OsGAMYB, OsTDR and OsbHLH142 during late pollen development. In brief, the rice GA3ox1 is a crucial gene that modulates pollen starch granule accumulation and pollen wall development at the gametophytic phase.

Development of a bead-based assay for detection of three banana-infecting viruses

Background

Banana bunchy top virus (BBTV), cucumber mosaic virus (CMV) and banana streak virus (BSV) are important banana viruses, there are possible infections frequently with several viruses in field. Since the viruses are readily trasmitted in vegetative propagules, which pose a threat to banana production in banana-growing areas.

Methods

A multiplex polymerase chain reaction (PCR) protocol combined with LiquiChip analysis to identify BSV, BBTV, and CMV, with consistent amplification of plant ubiquitin (UBQ), the banana plant messenger RNA used as a procedural control. Multiplex reverse transcription (RT)-PCR amplicons were extended by allele-specific primers, followed by hybridization with carboxylated microspheres containing unique fluorescent oligonucleotides, which were detected using the LiquiChip 200 workstation.

Results

In this study, we aimed to develop a rapid, sensitive, and simultaneous detection method for BSV, BBTV, and CMV using a bead-based multiplex assay that can be applied in routine diagnosis. We demonstrated that this detection system was extremely efficient and highly specialized for differentiating individual in a mixture of viruses while being ten times more sensitive than traditional RT-PCR. The development of this method makes it feasible to detect banana viruses in field collected leaf samples.

Comparisons within the Rice GA 2-Oxidase Gene Family Revealed Three Dominant Paralogs and a Functional Attenuated Gene that Led to the Identification of Four Amino Acid Variants Associated with GA Deactivation Capability

BACKGROUND

GA 2-oxidases (GA2oxs) are involved in regulating GA homeostasis in plants by inactivating bioactive GAs through 2β-hydroxylation. Rice GA2oxs are encoded by a family of 10 genes; some of them have been characterized, but no comprehensive comparisons for all these genes have been conducted.

RESULTS

Rice plants with nine functional GA2oxs were demonstrated in the present study, and these genes not only were differentially expressed but also revealed various capabilities for GA deactivation based on their height-reducing effects in transgenic plants. Compared to that of wild-type plants, the relative plant height (RPH) of transgenic plants was scored to estimate their reducing effects, and 8.3% to 59.5% RPH was observed. Phylogenetic analysis of class I GA2ox genes revealed two functionally distinct clades in the Poaceae. The OsGA2ox3, 4, and 8 genes belonging to clade A showed the most severe effect (8.3% to 8.7% RPH) on plant height reduction, whereas the OsGA2ox7 gene belonging to clade B showed the least severe effect (59.5% RPH). The clade A OsGA2ox3 gene contained two conserved C186/C194 amino acids that were crucial for enzymatic activity. In the present study, these amino acids were replaced with OsGA2ox7-conserved arginine (C186R) and proline (C194P), respectively, or simultaneously (C186R/C194P) to demonstrate their importance in planta. Another two amino acids, Q220 and Y274, conserved in OsGA2ox3 were substituted with glutamic acid (E) and phenylalanine (F), respectively, or simultaneously to show their significance in planta. In addition, through sequence divergence, RNA expression profile and GA deactivation capability analyses, we proposed that OsGA2ox1, OsGA2ox3 and OsGA2ox6 function as the predominant paralogs in each of their respective classes.

CONCLUSIONS

This study demonstrates rice has nine functional GA2oxs and the class I GA2ox genes are divided into two functionally distinct clades. Among them, the OsGA2ox7 of clade B is a functional attenuated gene and the OsGA2ox1, OsGA2ox3 and OsGA2ox6 are the three predominant paralogs in the family.

Improving nitrogen use efficiency by manipulating nitrate remobilization in plants

Increasing nitrogen use efficiency (NUE) is critical to improve crop yield, reduce N fertilizer demand and alleviate environmental pollution. N remobilization is a key component of NUE. The nitrate transporter NRT1.7 is responsible for loading excess nitrate stored in source leaves into phloem and facilitates nitrate allocation to sink leaves. Under N starvation, the nrt1.7 mutant exhibits growth retardation, indicating that NRT1.7-mediated source-to-sink remobilization of stored nitrate is important for sustaining growth in plants. To energize NRT1.7-mediated nitrate recycling, we introduced a hyperactive chimeric nitrate transporter NC4N driven by the NRT1.7 promoter into the nrt1.7 mutant. NRT1.7p::NC4N::3' transgenic plants accumulated more nitrate in younger leaves, and ¹⁵NO₃^- tracing analysis revealed that more ¹⁵N was remobilized into sink tissues. Consistently, transgenic Arabidopsis, tobacco and rice plants showed improved growth or yield. Our study suggests that enhancing source-to-sink nitrate remobilization represents a new strategy for enhancing NUE and crop production.

Heterologous expression of rice 9-cis-epoxycarotenoid dioxygenase 4 (OsNCED4) in Arabidopsis confers sugar oversensitivity and drought tolerance

BACKGROUND

The 9-cis-epoxycarotenoid dioxygenases OsNCED4 was cloned from rice in conjunction with OsNCED 1-3 and 5, of which 3 has been shown to function in ABA biosynthesis and alteration of leaf morphology. In higher plants, NCEDs have been shown to be key enzymes controlling ABA biosynthesis and belong to a differentially expressed gene family. Aside from OsNCED3, it remains largely unknown if other OsNCED genes are involved in ABA biosynthesis in rice. Thus, transgenic Arabidopsis plants overexpressing OsNCED4 were generated in the 129B08/nced3 mutant background to explore OsNCED4 function in ABA biosynthesis.

RESULTS

Heterologous expression of OsNCED4 in Arabidopsis increased ABA levels and altered plant size and leaf shape, delayed seed germination, caused sugar oversensitivity in post-germination growth, and enhanced tolerance to drought. The native OsNCED3 and OsNCED4 promoters were expressed in an overlapping pattern in rice seeds and young seedlings, suggesting possible functional redundancy between OsNCED3 and OsNCED4. At the one-leaf stage, similar regulation of OsNCED3 and OsNCED4 gene expression in roots or leaves in response to moderate salt stress (150 mM NaCl) was observed.

CONCLUSION

Like OsNCED3, OsNCED4 is functionally active in ABA biosynthesis in rice. OsNCED3 and OsNCED4 might play redundant roles in controlling ABA biosynthesis in rice, as suggested by GUS staining assay, but this should be further analyzed through complementation of rice NCED knockout mutants.

Expression of Raf kinase inhibitor protein in human hepatoma tissues by two-dimensional gel electrophoresis and matrix-assisted laser desorption/ionization time-of-flight methods

PURPOSE

Hepatocellular carcinoma (HCC) is the most common malignant liver tumor. To reduce the mortality and improve the effectiveness of therapy, it is important to search for changes in tumor-specific biomarkers whose function may involve in disease progression and which may be useful as potential therapeutic targets. Materials and Mehtods: In this study, we use two-dimensional polyacrylamide gel electrophoresis (2-DE) and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry to observe proteome alterations of 12 tissue pairs isolated from HCC patients: Normal and tumorous tissue. Comparing the tissue types with each other, 40 protein spots corresponding to fifteen differentially expressed between normal and cancer part of HCC patients.

RESULTS

Raf kinase inhibitor protein (RKIP), an inhibitor of Raf-mediated activation of mitogen-activated protein kinase/extracellular signal-regulated kinase, may play an important role in cancer metastasis and cell proliferation and migration of human hepatoma cells. RKIP may be considered as a marker for HCC, because its expression level changes considerably in HCC compared with normal tissue. In addition, we used the methods of Western blotting and real time-polymerase chain reaction to analysis the protein expression and gene expression of RKIP. The result showed RKIP protein and gene expression in tumor part liver tissues of HCC patient is lower than peritumorous non-neoplastic liver tissue of the corresponding HCC samples.

CONCLUSION

These results strongly suggest that RKIP may be considered to be a marker for HCC and RKIP are down-regulated in liver cancer cell.

Solid freeform-fabricated scaffolds designed to carry multicellular mesenchymal stem cell spheroids for cartilage regeneration

Three-dimensional (3D) cellular spheroids have recently emerged as a new trend to replace suspended single cells in modern cell-based therapies because of their greater regeneration capacities in vitro. They may lose the 3D structure during a change of microenvironment, which poses challenges to their translation in vivo. Besides, the conventional microporous scaffolds may have difficulty in accommodating these relatively large spheroids. Here we revealed a novel design of microenvironment for delivering and sustaining the 3D spheroids. Biodegradable scaffolds with macroporosity to accommodate mesenchymal stem cell (MSC) spheroids were made by solid freeform fabrication (SFF) from the solution of poly(D,L-lactide-co-glycolide). Their internal surface was modified with chitosan following air plasma treatment in order to preserve the morphology of the spheroids. It was demonstrated that human MSC spheroids loaded in SFF scaffolds produced a significantly larger amount of cartilage-associated extracellular matrix in vitro and in NOD/SCID mice compared to single cells in the same scaffolds. Implantation of MSC spheroid-loaded scaffolds into the chondral defects of rabbit knees showed superior cartilage regeneration. This study establishes new perspectives in designing the spheroid-sustaining microenvironment within a tissue engineering scaffold for in vivo applications.

An orthogonal neural network for function approximation

This paper presents a new single-layer neural network which is based on orthogonal functions. This neural network is developed to avoid the problems of traditional feedforward neural networks such as the determination of initial weights and the numbers of layers and processing elements. The desired output accuracy determines the required number of processing elements. Because weights are unique, the training of the neural network converges rapidly. An experiment in approximating typical continuous and discrete functions is given. The results show that the neural network has excellent performance in convergence time and approximation error.

Swollen head syndrome in Taiwan-isolation of an avian pneumovirus and serological survey

Outbreaks of swollen head syndrome (SHS) were observed in two broiler and two broiler-breeder farms in Taiwan. The disease was characterized by oedematous swelling of the head, especially surrounding the eyelids, the neck and wattles. Avian pneumovirus and Escherichia coli were isolated from birds in all four farms. In addition, Staphylococcus aureus and infectious bursal disease virus were each isolated from one farm. A serological survey of 398 birds from 11 broiler breeder farms showed 86.4% (344) of them had ELISA antibodies against turkey rhinotracheitis virus.

A compact computational model for cell construct development in perfusion culture

A problem nowadays tissue engineers encounter in developing sizable tissue implants is the nonuniform spread of cells and/or extracellular matrices. Research shows such a nutrients transport restriction may be improved by employing hydrodynamic culture systems. We propose a compact model for the simulation of cell growth in a porous construct under direct perfusion. Unlike the previous model proposed in the literature, which composes a cellular scaffold sandwiched between two culture media layers, the current model includes only the scaffold layer to simplify the mathematical and computational complex. Results show the present single-layer model can predict cell spreads and the nutrient and metabolic waste distribution as accurately as does the three-layer model. Only if the hydrodynamic aspects such as the pressure and viscous stress are prominent to know, should the more sophisticated analyses with the three-layer model be employed. The compact model provides comparable investigations for the tissue-engineering construct developments.

A rice phenomics study--phenotype scoring and seed propagation of a T-DNA insertion-induced rice mutant population

With the completion of the rice genome sequencing project, the next major challenge is the large-scale determination of gene function. As an important crop and a model organism, rice provides major insights into gene functions important for crop growth or production. Phenomics with detailed information about tagged populations provides a good tool for functional genomics analysis. By a T-DNA insertional mutagenesis approach, we have generated a rice mutant population containing 55,000 promoter trap and gene activation or knockout lines. Approximately 20,000 of these lines have known integration sites. The T0 and T1 plants were grown in net "houses" for two cropping seasons each year since 2003, with the mutant phenotypes recorded. Detailed data describing growth and development of these plants, in 11 categories and 65 subcategories, over the entire four-month growing season are available in a searchable database, along with the genetic segregation information and flanking sequence data. With the detailed data from more than 20,000 T1 lines and 12 plants per line, we estimated the mutation rates of the T1 population, as well the frequency of the dominant T0 mutants. The correlations among different mutation phenotypes are also calculated. Together, the information about mutant lines, their integration sites, and the phenotypes make this collection, the Taiwan Rice Insertion Mutants (TRIM), a good resource for rice phenomics study. Ten T2 seeds per line can be distributed to researchers upon request.

Enhancement of cell growth in tissue-engineering constructs under direct perfusion: Modeling and simulation

Perfusion bioreactors improve mass transfer in cell-scaffold constructs. We developed a mathematical model to simulate nutrient flow through cellular constructs. Interactions among cell proliferation, nutrient consumption, and culture medium circulation were investigated. The model incorporated modified Contois cell-growth kinetics that includes effects of nutrient saturation and limited cell growth. Nutrient uptake was depicted through the Michaelis-Menton kinetics. To describe the culture medium convection, the fluid flow outside the cell-scaffold construct was described by the Navier-Stokes equations, while the fluid dynamics within the construct was modeled by Brinkman's equation for porous media flow. Effects of the media perfusion were examined by including time-dependant porosity and permeability changes due to cell growth. The overall cell volume was considered to consist of cells and extracellular matrices (ECM) as a whole without treating ECM separately. Numerical simulations show when cells were cultured subjected to direct perfusion, they penetrated to a greater extent into the scaffold and resulted in a more uniform spatial distribution. The cell amount was increased by perfusion and ultimately approached an asymptotic value as the perfusion rates increased in terms of the dimensionless Peclet number that accounts for the ratio of nutrient perfusion to diffusion. In addition to enhancing the nutrient delivery, perfusion simultaneously imposes flow-mediated shear stress to the engineered cells. Shear stresses were found to increase with cell growth as the scaffold void space was occupied by the cell and ECM volumes. The macro average stresses increased from 0.2 mPa to 1 mPa at a perfusion rate of 20 microm/s with the overall cell volume fraction growing from 0.4 to 0.7, which made the overall permeability value decrease from 1.35 x 10(-2)cm(2) to 5.51 x 10(-4)cm(2). Relating the simulation results with perfusion experiments in literature, the average shear stresses were below the critical value that would induce the chondrocyte necrosis.

A rice gene activation/knockout mutant resource for high throughput functional genomics

Using transfer DNA (T-DNA) with functions of gene trap and gene knockout and activation tagging, a mutant population containing 55,000 lines was generated. Approximately 81% of this population carries 1-2 T-DNA copies per line, and the retrotransposon Tos17 was mostly inactive in this population during tissue culture. A total of 11,992 flanking sequence tags (FSTs) have been obtained and assigned to the rice genome. T-DNA was preferentially ( approximately 80%) integrated into genic regions. A total of 19,000 FSTs pooled from this and another T-DNA tagged population were analyzed and compared with 18,000 FSTs from a Tos17 tagged population. There was difference in preference for integrations into genic, coding, and flanking regions, as well as repetitive sequences and centromeric regions, between T-DNA and Tos17; however, T-DNA integration was more evenly distributed in the rice genome than Tos17. Our T-DNA contains an enhancer octamer next to the left border, expression of genes within genetics distances of 12.5 kb was enhanced. For example, the normal height of a severe dwarf mutant, with its gibberellin 2-oxidase (GA2ox) gene being activated by T-DNA, was restored upon GA treatment, indicating GA2ox was one of the key enzymes regulating the endogenous level of GA. Our T-DNA also contains a promoterless GUS gene next to the right border. GUS activity screening facilitated identification of genes responsive to various stresses and those regulated temporally and spatially in large scale with high frequency. Our mutant population offers a highly valuable resource for high throughput rice functional analyses using both forward and reverse genetic approaches.

Refolding and characterization of a yeast dehydrodolichyl diphosphate synthase overexpressed in Escherichia coli

Dehydrodolichyl diphosphate synthase (DDPPs) catalyzes the sequential condensation of isopentenyl diphosphate with farnesyl diphosphate to synthesize long-chain dehydrodolichyl diphosphate, which serves as a precursor of glycosyl carrier in glycoprotein biosynthesis in eukaryotes. To perform kinetic and structural studies of DDPPs, we have expressed yeast DDPPs using Escherichia coli as the host cell. Thioredoxin and His tag were utilized to increase the solubility of the recombinant protein and facilitate its purification using Ni-nitrilotriacetic acid (NTA) column. The protein was overexpressed in E. coli but mostly existed in pellet in the absence of detergent. The low quantity of soluble DDPPs was purified using Ni-NTA, Mono Q anion-exchange, and size-column chromatographies. The protein in the pellet was solubilized with 7 M urea and purified using Ni-NTA under denaturing condition. The protein refolding was achieved via the stepwise dialysis to remove the denaturant in the presence of 6 mM beta-mercaptoethanol. Detergent n-octyl-beta-d-glucopyranoside and Triton X-100 increased the solubility of the DDPPs so that refolding can be performed at higher protein concentration. Alternatively, on-column refolding was carried out in a single step to obtain the active protein in large quantities. beta-Mercaptoethanol and Triton were both required in this quick refolding process. The kinetic studies indicated that the soluble and refolded DDPPs have comparable activities (k(cat) = 2 x 10(-4) s(-1)). Unlike its bacterial homologue, undecaprenyl diphosphate synthase, yeast DDPPs activity was not enhanced by Triton.

Application of three-dimensional orthogonal neural network to craniomaxillary reconstruction

The purpose of this investigation is to establish a practical method to predict and create surface a profile of bone defects by a well-trained 3-D orthogonal neural network. First, the coordinates of the skeletal positions around the boundary of bone defects are input into the 3-D orthogonal neural network to train it to learn the scattering characteristic. The 3-D orthogonal neural network avoids local minima and converges rapidly. After the neural network has been well trained, the mathematic model of the bone defect surface is generated, and the pixel positions are derived. Herein, to verify its performance the proposed method is applied on a patient with a craniofacial defect.

A methodology for evaluation of boundary detection algorithms on breast ultrasound images

Image segmentation is the partition of an image into a set of non-overlapping regions that comprise the entire image. The image is decomposed into meaningful parts, which are uniform with respect to certain characteristics, such as grey level or texture. This study presents a novel methodology to evaluate ultrasound image segmentation algorithms. The sonographic features can differentiate between various sized malignant and benign breast tumours. The clinical experiment can determine whether a tumour is benign or not, based on contour, shape, echogenicity and echo texture. Further study of the standardized sonographic features, especially the tumour contour and shape, will improve the positive predictive value and accuracy rate in breast tumour detection. The effectiveness of using this methodology is illustrated by evaluating image segmentation on breast ultrasound images. Via definite segmentation, the appreciated tumour shape and contour can be ascertained. Furthermore, this method can enhance the ability of ultrasound to distinguish between benign and malignant breast lesions.

Application of orthogonal neural network to craniomaxillary reconstruction

Traditionally, the orthopaedist, according to their past experience, reconstructs damaged area while the operation is in progress. This may prolong the operation and cause the wound to become infected. Most importantly it is difficult to precisely match the skeletal defect. A well-disciplined network of prediction re-fabricates the damaged area through automation. This research is based on the CT image file, which is the product of X-ray computed tomography (CT), and computes the skeletal positions around the damaged area through image processing and boundary detection. The skeletal positions are inputted into the orthogonal neural network and discipline the network so that it possesses the scattering characteristic of bone. The network then calculates skeletal positions in the damaged area and revises the former CT image file to rebuild a 3D model. Accordingly, in comparison with a manual sketch, the orthogonal neural network forecast is more geometrically precise. Moreover, the forecast satisfies the second order derivative, which is a continuous function, and the edge of the fabricated bone is therefore kept smoother.

Development of a robotic navigation system for neurosurgery

This paper presents a robotic navigation system for image-guided neurosurgery, which can be applied to the treatment of Parkinson's disease and biopsy of brain tumor. The system integrates a computer for real-time display of brain anatomy, a magnetic tracking device for measuring the positions and orientations of surgical instruments, and a robot manipulator for guiding surgical instruments to the preplanned positions and orientations. The computer display of brain anatomy offers a convenient tool for surgeons to diagnose brain disease and to plan safe surgical paths; while the tracking device assists the robot manipulator to automatically guide surgical instruments to the preplanned direction. The registrations among the tracking device, the image system, and the robot are completed on the base of coordination mappings of external markers. An experiment of using a skull model for simulating a robotic biopsy of brain tumor has been done to verify the performance of the navigation system. The result shows that the system can accomplish a positioning accuracy around 2 mm.

Succinylcholine-induced cardiac arrest in unsuspected becker muscular dystrophy--a case report

A five year-old boy undergoing elective tonsillectomy sustained cardiac arrest following the administration of a single dose of succinylcholine during induction of anesthesia. With a 10-minute cardiopulmonary resuscitation (CPR) during which intravenous calcium gluconate, epinephrine, and sodium bicarbonate were given and DC counter shock applied, we were successful to restore cardiac activity without neurological sequelae. The cause of cardiac arrest we speculated was hyperkalemia, possibly secondary to succinylcholine-induced rhabdomyolysis. It is suggested that succinylcholine should not be used in patients with known or suspected muscular dystrophy.

A PC-based surgical simulator for laparoscopic surgery

Surgical simulators for minimally invasive surgery have been developing in the 1990s. Most of them use high-end UNIX workstations for real-time simulation of complex human organ models. Only few of them have input devices with force feedback. Recently, personal computer technologies have made real-time display of relatively complex models feasible. We are developing an Intel-based laparoscopic surgical simulator that provides near real-time intuitive interaction between the trainee and simulated models of human organs. The surgical simulator has a prototypical scenario of cholecystectomic surgery. It can interactively simulate the deformation and cutting of cystic duct and vein. In addition, a set of input devices with force feedback has been designed and tested to imitate the manipulation of surgical instruments. The input device has five degrees of freedom and three of them are driven by DC motors to produce force feedback.

Unilateral pulmonary edema during general anesthesia--report of two cases

Unilateral presentation of pulmonary edema, though well known to occur, is an uncommon entity. Previous reviews of this subject have discussed the different etiologies, which include rapid reexpansion of collapsed lung, down lung syndrome (gravitational edema), systemic-to-pulmonary arterial shunts, heart failure, compression or occlusion of pulmonary vasculatures, obstruction of a bronchus and an acute manifestation of neuropulmonary reaction (neurogenic pulmonary edema). Occurrence of this complication during surgery, however, is even rarer. We report 2 cases of unilateral pulmonary edema occurring during general anesthesia for elective surgery.

Post-remission intensive consolidation with high-dose cytarabine-based chemotherapy and granulocyte colony-stimulatory factor in adults with acute myelogenous leukemia: a preliminary report

BACKGROUND

Modern induction chemotherapy produce 60% to 80% complete remission in adults with newly diagnosed acute myelogenous leukemia (AML). A major challenge is to eradicate subclinical disease in remission and prevent leukemic relapse. Intensive post-remission chemotherapy was proved of comparable disease-free survival as BMT.

METHODS

From February 1992 to to March 1995, twelve patients with AML, aged 15 to 57 y/o, received intensive consolidation chemotherapy immediately after the first complete remission. The chemotherapy included either 4 courses of high dose Arac (HiDAC), 3 gm/m2 q12h x3 days, or 2 courses of HiDAC (4 days) plus mitoxantrone for 3 days and etoposide for 7 days (HiDAC-3-7). Granulocyte colony-stimulating factor (G-CSF) used used 24 hours after chemotherapy until absolute neutrophile count greater than 500/mm3.

RESULTS

Totally 24 courses of high dose chemotherapy were given. The median duration of severe neutropenia (absolute neutrophile count < or = 500/mm3) was 12 days, thrombocytopenia (< or = 50,000/mm3) 18 days, fever > or = 38 degrees C 6 days, and from severe neutropenia (absolute neutrophile count < or = 500/mm3) was 12 days, thrombocytopenia (< or = 50,000/mm3) 18 days, fever > or = 38 degrees C 6 days, and from severe neutropenia (< or = 500/mm3) to infection 4 days. Infection was the most frequent complication during HiDAC treatment. No toxic death was noted. After a median follow-up of 16 months, early relapse was noted in 3 patients (2, 4, and 5 months, respectively), and late relapse in two patients (11 and 20 months, respectively). Seven patients remained in complete remission status after a median follow-up of 14+ months (7+ to 37+ months).

CONCLUSIONS

Intensive consolidation chemotherapy is well tolerable and may prolong remission duration when used in the early post-remission phase of AML.

Effects of opioid agonists and opioid antagonists in endotoxic shock in rats

Endotoxic shock is presented with a complex pathophysiology and is associated with high mortality. Recently, it has been reported that endogenous opioids play an important role in endotoxic shock. Pressor effect of naloxone in shock may be mediated through antagonism of endogenous opioid inhibition of the sympatho-adrenal catecholaminergic system. In endotoxemic animal, circulating catecholamine levels were not elevated by naloxone. It is possible that naloxone acts upon opiate receptors to enhance catecholamine actions at the receptor level or post-receptor level. We investigated endotoxic shock using a rat model. The animals anesthetized with phenobarbital were infused with E. coli LPS for 30 minutes. They were divided into 5 groups. After an endotoxin i.v. infusion of 15 mg/kg (LD 60), a significant fall in mean arterial pressure (MAP), heart rate and pH occurred in all groups. Treatment with naloxone or buprenorphine or naloxone + epinephrine resulted in significant improvement in MAP, pH and base excess. Treatment with morphine resulted in a decrease in MAP and an increase in heart rate. The pressor response to epinephrine 10, 30, 60 microgram/kg i.v. caused an increase of 62%, 48% and 17% of control values respectively in endotoxic treated rats. The duration of the pressor response to epinephrine was significantly increased by naloxone, although no significant effects on survival were seen at 4 hours after the start of treatment. These findings suggest that the buprenorphine may prove to be an alternative to naloxone, the co-administration of naloxone and epinephrine may be of benefit in the management of septic shock.