Developmental changes in electroencephalogram for term and preterm infants using an autoregressive model

The purpose of the present study was to clarify the developmental changes of electroencephalogram (EEG) background activity in term and preterm infants that take place with increasing conceptional age (CA) through an autoregressive (AR) model. Polygraphical EEG recordings were obtained from 76 healthy term and preterm infants with a CA ranging between 31 and 40 weeks. Decreases in total power and component power of δ were noted with CA during burst activity (BA) in quiet sleep (QS) and during active sleep (AS). Increases in total power and component power of δ were noted with CA during interburst interval activity (IBIA) of QS. Regression analysis (RA) of the information amount (IA) indicated a negative correlation with increasing CA in AS and in the monopolar EEG tracings Fp1, C3, O1 and O2 in BA, and a positive correlation in O1 in IBIA. Regression analysis of the IA of δ indicated a negative correlation with increasing CA in AS and in Fp1, C3, O1 and O2 in BA, and a positive correlation in O1 in IBIA. Regression analysis of the IA of δ indicated a negative correlation with increasing CA in BA and AS. These results showed that the high voltage slow wave component changed to a low voltage slow one with development in AS and that BA was longer in duration and lower in power with increasing CA, while IBIA was shorter in duration and higher in power. In conclusion, significant developmental changes occur in all derivatives of AS. Even though the EEG of BA and IBIA change separately, they are followed by EEG of QS in a continuous pattern.     

FLUMAZENIL DOES NOT ANTAGONIZE HALOTHANE, THIAMYLAL OR PROPOFOL ANAESTHESIA IN RATS{dagger}

We have studied the effects of flumazenil on sleep time andEEG in rats anaesthetized with 1.5% halothane, propofoi 20 mgkg^–1, thiamylal 30 mg kg^–1, or combinations of diazepam5 mg kg^–1 and anaesthetic agents. We also studied theeffects of flumazenil 0.3, 3 and 30 mg kg^–1 on behaviourand EEG. Flumazenil 0.3 and 3 mg kg^–1 alone had no effecton behaviour or EEG, but flumazenil 30 mg kg^–1 had depressiveeffects similar to those of diazepam on behaviour and EEG. Flumazenil0.3, 3 and 30 mg kg^–1 i.v., antagonized the effects ofdiazepam 10 mg kg^–1 i.v. on behaviour and EEG. Flumazenilhad no antagonistic effect on sleep time induced by anaestheticagents, but flumazenil 30 mg kg^–1 potentiated propofol-inducedanaesthesia. Flumazenil did not affect anaesthesia-induced EEGchanges. Diazepam 5 mg kg^–1 potentiated anaesthesia. Flumazenilantagonism of diazepam potentiation varied with anaestheticagent: flumazenil 0.3 mg kg^–1 antagonized diazepam actionin halothane anaesthesia, but 30 mg kg^–1 was requiredin propofoi anaesthesia; this large dose was insufficient inthiamylal anaesthesia. ^*Present address: Department of Anesthesia, Omiya Medical Center,Omiya 330, Japan.      

Adjuvant Immunotherapy for Malignant Brain Tumors

New methods of adjuvant immunotherapy were introduced for thetreatment of malignant brain tumors. Allogeneic bone marrowcell transfusion or local intratumoral infusion of allogeneicor autologous peripheral white blood cells were conducted on18 patients having malignant glioma, after ordinary treatmentof operation, radiation or chemotherapy. The survival rate ofthese patients was significantly prolonged when compared withthe rate normally expected. No side effects were noted. Morphologicalchanges of cells in the cerebrospinal fluid taken from the intratumoralcavity, before and after infusion of peripheral white bloodcells, were studied. Cytolysis and phagocytosis of tumor cellsby macrophages were observed. Suppressive mechanism of immunologicallycompetent cells on glioma cells was partly studied, cytologicallyin vitro.     

An automated data algorithm to distinguish screening and diagnostic colorectal cancer endoscopy exams

Despite questions about accuracy, automated data are used increasingly for research and quality measurement. The goal of this study was to develop an automated data algorithm designed to distinguish screening and diagnostic endoscopy (sigmoidoscopy and colonoscopy) exams. We assessed the algorithm's ability to correctly classify the exams using paper medical records as the "gold standard." The algorithm used diagnostic codes to identify the indication of the endoscopies. The algorithm's ability to classify the indication varied by endoscopy exam. The sensitivities for identifying diagnostic sigmoidoscopy and colonoscopy were 48.1% and 23.8%, respectively. The algorithm missed most of the diagnostic endoscopies. Conversely, the sensitivities for identifying screening sigmoidoscopy and colonoscopy were high (87.9% and 84.4%, respectively) but were associated with low specificities. Our findings suggest that studies relying solely on automated data overestimate screening rates if indication is not considered. The automated algorithm presented here needs further improvements to better differentiate screening from diagnostic exams.     

Mucosal immunization of sheep with a Maedi-Visna virus (MVV) env DNA vaccine protects against early MVV productive infection

Gene gun mucosal DNA immunization of sheep with a plasmid expressing the env gene of Maedi-Visna virus (MVV) was used to examine the protection against MVV infection in sheep from a naturally infected flock. For immunization, sheep were primed with a pcDNA plasmid (pcDNA-env) encoding the Env glycoproteins of MVV and boosted with combined pcDNA-env and pCR3.1-IFN-gamma plasmid inoculations. The pcDNA plasmid used in the control group contained the lacZ coding sequences instead of the env gene. Within a month post-challenge, the viral load in the vaccinated group was lower (p < or = 0.05) and virus was only detected transiently compared with the control group. Furthermore, 2 months later, neutralizing antibodies (NtAb) were detected in all the control animals and none of the vaccinated animals (p < or = 0.01). These results demonstrated a significant early protective effect of this immunization strategy against MVV infection that restricts the virus replication following challenge in the absence of NtAb production. This vaccine protective effect against MVV infection disappeared after two years post-challenge, when active replication of MVV challenge strain was observed. Protection conferred by the vaccine could not be explained by OLA DRB1 allele or genotype differences. Most of the individuals were DRB1 heterozygous and none was totally resistant to infection.     

Improvement in the performance of the adaptive neighborhood contrast enhancement technique based on entropy

This paper presents an improved adaptive-neighborhood-contrast-enhancement (ANCE) method for the improvement of medical image quality. The ANCE method consists of computing the local contrast around each pixel using a variable neighborhood whose size depends on the statistical properties around the given pixel. The obtained contrast image is then transformed into a new contrast image using a contrast enhancement function. Finally, a contrast-enhanced image is obtained by applying inverse contrast transform to the previous step. This technique provides the advantages of enhancing or preserving image contrast while suppressing noise. However, it does have a drawback. The performance of the ANCE method largely depends on how to determine the parameters used in the processing steps. The present study proposes a novel method for optimal and automatic determination of several parameters using entropy. To quantitatively compare the performance of the proposed method with that of the ANCE method, computer-simulated images are generated. The output-to-input SNR level and the mean squared error are used as comparison criteria. Results demonstrated the superiority of the proposed method. Moreover, we have applied our new algorithm to echocardiograms and mammograms. Our results showed that the proposed method has the potential to become useful for improving the image quality of medical images.     

Efficient and faithful in vitro translation of natural and synthetic mRNA with human ribosomes

Efficient systems for in vitro translation are of importance for biochemical and gene expression studies as well as for biotechnological developments. We optimized a cell-free translation system using subcellular fractions from human placenta and high quality placental tRNAs isolated using a simple and fast procedure. The postmitochondrial fraction or a reconstituted system containing soluble proteins plus polysomes were able to efficiently translate endogenous and exogenous mRNAs. Optima for ions, enzymes, tRNA and energy mix components were determined for a poly(U)-directed poly(Phe) synthesis test. The use of homologous tRNAPhe, omission of commercial creatine kinase, and addition of 3.5 mM spermidine at near physiological magnesium concentration (2.5 mM), were the most significant improvements. Under optimal conditions, poly(Phe) synthesis proceeded at a maximal initial rate of 1.2 Phe/80S/min at 37 degrees C, while natural mRNA translation by S-30 started at a near in vivo estimated rate of 0.3-0.5 amino acid/80S/sec. Furthermore, natural mRNA directed the synthesis of a family of polypeptides closely resembling the pattern of cytoplasmic proteins in both, molecular weight and relative amounts. This efficient and faithful system is of interest for biochemical studies of the human translational machinery, as well as a basis for screening new drugs affecting protein synthesis in pathogenic microorganisms.