A new proposal on the neural component of the control system of renal blood flow. Analysis using digital simulation

A mathematical, non-lineal model for digital simulation of the neural control of blood renal flow (BRF) has been built, by using the system dynamic techniques. The control mechanisms considered have been the BRF regulation by means of a renal intrinsic system, and by means of an RNA-dependent system, being the latter a product of the peripheral sympathetic activity, of a tonic inhibitory system with a central origin, and of a system that inhibits this last one, which has an intrarenal origin. For the validation of the model, a spinal section has been simulated, and the data have been compared with the reported in the bibliography. The use of this model permits an approach to the study of different variables in physiological or pathological circumstances in man, especially of those involved in the neural regulation of the BFR, obviating the technical and ethical obstacles of experimental techniques and leading to the design of new animal trials.     

Transport of 4-hydroxyphenylacetic acid in Klebsiella pneumoniae.

Klebsiella pneumoniae M5a1 has been shown to possess an inducible transport system for 4-hydroxyphenylacetate (4-HPA). This transport system has a Kt of 16.3 microM and a maximal velocity of 31.2 nmol/min (milligrams dry weight). The transport system has been inhibited by inhibitors of energy metabolism with a concomitant decrease in cellular ATP concentrations, and the 4-HPA binding activity has been detected in the crude shock extracts. All these observations indicate that 4-HPA uptake is an active transport which involves a periplasmic binding protein and it seems to be energized by phosphate bond energy.     

Cellular biosensing system for discovery of protein synthesis inhibitors with an electrochemical phosphate modulator to regulate the acid phosphatase gene expression of Saccharomyces cerevisiae

A cellular biosensing system for screening protein synthesis inhibitors has been developed by linking an electrochemical phosphate modulator and matrix-immobilized yeast cells with an optical sensing device. To screen the protein synthesis inhibitors, yeast phosphatase gene regulating system has been employed by linking an electrochemical phosphate modulator. Since the yeast phosphatase gene coding gammaAPase is expressed, when the phosphate concentration in solution is lowered below the threshold, the gammaAPase production is triggered by lowering the phosphate concentration with the electrochemical phosphate modulator, and monitored continuously with the photometric device. The electrochemical phosphate modulator was assembled with matrix-immobilized yeast cells. The module could insert to ordinal cuvette to monitor the induced gammaAPase activity in an ordinal photometer. Using the system, induction profile of protein synthesis was easily observed and was affected remarkably by various protein synthesis inhibitors. This seems promising that the system can be applied for first screening process of de novo protein inhibitors. The cellular biosensing system seems promising in screening protein synthesis inhibitors.     

Some Adaptive Features in the Respiratory System of Dineutes indicus Aubé (Coleoptera, Gyrinidae)

The spiracular structure characterized with a system of snarling dense outgrowths, has been studied in order to elucidate their reinterpreted role in respiration. The tracheal anatomy has undergone modifications to subserve a secondary function of reducing the metabolic heat in the thorax—a region of relatively high metabolic activity. Tracheation is so arranged as to enable this insect to lead successfully an amphibious existence. The rate of its oxygen consumption and its capacity to remain under water with an air bubble which functions as an efficient physical gill with temperature as an important limiting factor has been studied. Attempts have been made to analyse the anatomy of the respiratory system with reference to the insect's behaviour in its environment.     

Al-assisted, transputer based EMG system--concept, components and initial results

An EMG system has been developed capable of doing an EMG analysis as well as providing diagnostic support with the aid of an integrated expert system. The goal of this EMG system is to reduce the time of examination and to increase the reliability of the diagnosis. In order to obtain many parameters from the EMG signal, different analysing methods capable of running in parallel are needed. The system has been realized with a transputer network. Thus it is possible to distribute the software components to different processors with high level of efficiency. For software development we use the operating system Helios. This makes it possible to use the standard I/O environment X-Windows.     

Computer graphics with computerized tomography for functional neurosurgery

A computer graphics technique for computer-assisted stereotactic surgery is presented. The program is designed to aid the surgeon by presenting an on-line graphics display of stereotactic probes and electrodes superimposed on cross sections of the human brain stem. This technique simulates an otherwise blind surgical procedure on a graphics screen for use during surgery. An earlier system based around the DEC MINC-11 BA computer system has been used by the authors for the performance of stereotactic surgery with conventional ventriculography. This system has been upgraded and is now configured about an even more compact microprocessor-based hardware system with expanded graphics capabilities, which also allows its use with computerized tomography.     

Electron Microscopy of the Longitudinal Fibrillar Bundle and the Contractile Fibrillar System in Spirostomum ambiguum

SYNOPSIS. A study of the 'longitudinal fibrillar bundle' (LFB) and the 'contractile fibrillar system' (CFS) of a large protozoan ciliate, Spirostomum ambiguum , has been performed by means of an electron microscope. A system of sub-pellicular fibrils has been newly found and its function is discussed. Each LFB runs parallel with a longitudinal row of ciliary bases. It seems to be identical with the so-called kinetodesma. It is composed of tubular fibrils arranged in layered sheets, each of which contains 13 to 35 fibrils with the same diameter as the intra-ciliary fibrils and has a close connection to each of the ciliary bases. The CFS lies on a transitional plane between ectoplasm and endoplasm of the organism and forms a cobweb-like system of myofibrils as a whole. It stands in an intimate relationship with a characteristic vacuolar system. In a peristomial field, the fibrous structures are interrupted and somewhat thickened. A sub-pellicular system is composed of minute fibrils 20 to 26 mμ in diameter. The fibrils run parallel with each other in an antero-posterior direction, immediately beneath the inner pellicular membrane.     

The use of gas-sensor arrays to diagnose urinary tract infections

Sensorial analysis based on the utilisation of human senses, is one of the most important and straightforward investigation methods in food and chemical analysis. An electronic nose has been used to detect in vivo Urinary Tract Infections from 45 suspected cases that were sent for analysis in a UK Health Laboratory environment. These samples were analysed by incubation in a volatile generation test tube system for 4-5 h. The volatile production patterns were then analysed using an electronic nose system with 14 conducting polymer sensors. An intelligent model consisting of an odour generation mechanism, rapid volatile delivery and recovery system, and a classifier system based on learning techniques has been considered. The implementation of an Extended Normalised Radial Basis Function network with advanced features for determining its size and parameters and the concept of fusion of multiple classifiers dedicated to specific feature parameters has been also adopted in this study. The proposed scheme achieved a very high classification rate of the testing dataset, demonstrating in this way the efficiency of the proposed scheme compared with other approaches. This study has shown the potential for early detection of microbial contaminants in urine samples using electronic nose technology.     

A fiberoptic sensor system for cardiac monitoring and electrotherapy.

Commercially available cardiac pacemakers and implantable cardioverters/defibrillators (ICD) predominantly use the intracardiac derived electrocardiogram (ECG) for detection of arrhythmias. To achieve an automatic control of the heart frequency in accordance with cardiovascular strain and an improved detection of life-threatening arrhythmias, it is desirable to monitor the heart by an input signal correlated with the hemodynamic state. One possible approach to derive such a signal, is to measure the inotropy (mechanical contraction strength of the heart muscle). For this purpose an optoelectronic measurement system has been designed. The fundamental function of the system has been shown in earlier investigations using an isolated beating pig heart. In this paper further results showing the correlation of the fiberoptic sensor signal with the left ventricular stroke volume are presented. To make the system useful for implantable devices, further improvements with regard to power consumption and signal quality were achieved.     

Gankyrin与消化系统肿瘤关系的研究进展

消化系统肿瘤与多种肿瘤相关基因的异常表达密切相关,Gankyrin是一种癌基因,于肝癌、结直肠癌、胰腺癌等消化系统肿瘤中高表达,并通过依赖泛素的蛋白酶解系统介导多种转录因子、细胞周期调控蛋白以及抑癌蛋白如p53、Rb等的降解。研究表明,Gankyrin在消化系统肿瘤形成及细胞的生长周期调控中发挥重要作用,在消化系统肿瘤的早期诊断及判断预后方面具有一定的应用前景,同时也可能成为消化系统肿瘤基因治疗的潜在靶点。     

Automatic speech recognition — Can it improve the man-machine interface in medical expert systems?

Computer-aided medical diagnosis has existed for two decades, but has not yet attained widespread acceptance among physicians. It is proposed that automatic speech recognition may be a significant factor in the eventual acceptance of the technology by the medical profession. The current state-of-the-art of automatic speech recognition is briefly surveyed, and problems with the technology are discussed. A potential natural language interface with DIAG, an expert system for aiding in dermatologic diagnosis, is described. A system that has been developed for accepting input of body parts in freestyle format is presented as a prototype for a natural language interface with an automatic speech recognition device.     

New perspectives on cocaine addiction: recent findings from animal research

Research with laboratory animals has provided several insights into the nature of cocaine abuse and addiction. First, the nature of drug addiction has been reevaluated and the emphasis has shifted from physical dependence to compulsive drug-taking behavior. Second, animal studies suggest that cocaine is at least as addictive as heroin and possibly even more addictive. Third, cocaine is potentially more dangerous than heroin as evidenced by the higher fatality rate seen in laboratory animals given unlimited access to these drugs. Fourth, the neural basis of cocaine reinforcement has been identified and involves an enhancement of dopaminergic neurotransmission in the ventral tegmental dopamine system. Other addictive drugs (e.g., opiates) may also derive at least part of their reinforcing impact by pharmacologically activating this reward system. Fifth, although the biological consequences of repeated cocaine self-administration on central nervous system functioning are poorly understood, preliminary findings suggest that intravenous cocaine self-administration may decrease neural functioning in this brain reward system. This has important clinical implications because diminished functioning of an important brain reward system may significantly contribute to relapse into cocaine addiction. These and other findings from experimentation with laboratory animals suggest new considerations for the etiology and treatment of drug addiction.     

Molecular design of synthetic receptors with dynamic, imprinting, and allosteric functions

Sugar recognition in an aqueous system has been achieved using a boronic acid-diol interaction. Combination with an intramolecular amino group has enabled us to read out the binding process as a change in the fluorescence intensity. The novel interaction has been extended to dynamic sugar sensing utilizing an allosteric effect, molecular imprinting, and control of molecular assemblies.     

Development of a rapid and productive cell-free protein synthesis system

Due to recent advances in genome sequencing, there has been a dramatic increase in the quantity of genetic information, which has lead to an even greater demand for a faster, more parallel expression system. Therefore, interest in cell-free protein synthesis, as an alternative method for high-throughput gene expression, has been revived. In contrast toin vivo gene expression methods, cell-free protein synthesis provides a completely open system for direct access to the reaction conditions. We have developed an efficient cell-free protein synthesis system by optimizing the energy source and S30 extract. Under the optimized conditions, approximately 650 μg/mL of protein was produced after 2 h of incubation, with the developed system further modified for the efficient expression of PCR-amplified DNA. When the concentrations of DNA, magnesium, and amino acids were optimized for the production of PCR-based cell-free protein synthesis, the protein yield was comparable to that from the plasmid template.     

Anion exchange and anion-cation co-transport systems in mammalian cells

Electroneutral anion transfer in the Ehrlich ascites tumour cell has been found to occur by two separate mechanisms. One is an exchange diffusion system with many similarities to that found in erythrocytes, e.g. saturation kinetics with 'self-inhibition', a relatively pronounced temperature dependence, competitive interactions of Br-, NO3- and SCN-, and a low conductive PCl- of 4 x 10(-8) cm s-1. The main differences are that the Cl- flux in Ehrlich cells at 38 degrees C is one thousandth of the flux in red cells, and that the specificity of the system is less pronounced. It is suggested that the density of anion exchange sites in Ehrlich cells could be the same as in red blood cells, but with a lower turnover rate. The other system is an anion-cation co-transport system capable of mediating a secondary active Cl- influx. This system has a volume-regulatory function and is activated by a reduction in cell volume and intracellular [Cl-]. The two transport systems can be separated by using DIDS as an inhibitor of anion exchange and bumetanide as an inhibitor of co-transport. Under normal steady-state conditions Cl- flux is dominated by the exchange system. It is suggested that intracellular pH regulation can be achieved by the two systems operating in parallel, because the chloride disequilibrium maintained by the co-transport system can drive an influx of bicarbonate through the exchange mechanism.     

Automated breast cancer diagnosis based on fine needle aspiration

OBJECTIVE: To design and analyze an automated diagnostic system for breast carcinoma based on fine needle aspiration (FNA). STUDY DESIGN: FNA is a noninvasive alternative to surgical biopsy for the diagnosis of breast carcinoma. Widespread clinical use of FNA is limited by the relatively poor interobserver reproducibility of the visual interpretation of FNA images. To overcome the reproducibility problem, past research has focused on the development of automated diagnosis systems that yield accurate, reproducible results. While automated diagnosis is, by definition, reproducible, it has yet to achieve diagnostic accuracy comparable to that of surgical biopsy. In this article we describe a sophisticated new diagnostic system in which the mean sensitivity (of FNA diagnosis) approaches that of surgical biopsy. The diagnostic system that we devised analyzes the digital FNA data extracted from FNA images. To achieve high sensitivity, the system needs to solve large, equality-constrained, integer nonlinear optimization problems repeatedly. Powerful techniques from the theory of Lie groups and a novel optimization technique are built into the system to solve the underlying optimization problems effectively. The system is trained using digital data from FNA samples with confirmed diagnosis. To analyze the diagnostic accuracy of the system > 8,000 computational experiments were performed using digital FNA data from the Wisconsin Breast Cancer Database. RESULTS: The system has a mean sensitivity of 99.62% and mean specificity of 93.31%. Statistical analysis shows that at the 95% confidence level, the system can be trusted to correctly diagnose new malignant FNA samples with an accuracy of 99.44-99.8% and new benign FNA samples with an accuracy of 92.43-93.93%. CONCLUSION: The diagnostic system is robust and has higher sensitivity than do all the other systems reported in the literature. The specificity of the system needs to be improved.     

Mandibular matrix implant system: a method to restore skeletal support to the lower face

Disharmony between the skeletal support and the softtissue envelope is a common cause of aesthetic concerns regarding the lower face. A loss of volume or a genetically small mandible affects the aesthetics and function of the mouth, chin, and neck. Because of the limitations of correcting such problems with current implants made of silicone or porous polyethylene, the author developed an implant system and a method of restoring the entire volume of the mandible called the mandibular matrix implant system. This implant system is made of high-density porous polyethylene and is composed of an articulated wraparound geniomandibular implant and a wraparound gonial angle implant. A prejowl implant can be integrated in the system as an addition or as a replacement for a chin implant. This implant system has different sizes and projections, and it can be modified by carving to fit the requirements of most patients. Carving is done using an appropriate sizer. This implant system is indicated for use in patients with a congenitally small mandible, edentulous patients, and patients requesting facial enhancement. The mandibular matrix implant system is implanted either during a single procedure or simultaneously with a facial rejuvenation. The extended geniomandibular implant is introduced through an anterior oral sulcus incision or a submental incision. The mandibular angle implant is introduced through a retromolar incision. The posterior end of the chin implant overlaps the anterior end of the gonial implant, and screw fixation of each chin component helps to stabilize the entire system. Antibiotics, irrigation, and closure of the incisions are performed before any additional operative procedure. The complete system has been used in 13 patients; one additional patient had the complete system plus an overlapping additional left prejowl implant for correction of asymmetry. Complications were manageable; these included one mandibular angle implant displacement and one infection. The implant displacement required a reoperation to reset the implant. The infection was treated with irrigation and closed system suction; the implant was salvaged. The satisfaction of patients has been high, and the author can now solve aesthetic problems that in the past were considered unsolvable.     

The in vitro effects of Triton WR-1339 on lipid synthesis by bone cells.

Triton WR-1339, administered parenterally, has long been known to be a potent hyperlipemic agent. In vitro lipid biosynthesis is stimulated in liver and brain preparations from animals injected with Triton. Only in a perfused isolated liver system has an in vitro effect of Triton on lipid synthesis been demonstrated. In the present study, lipid biosynthesis has been shown to increase in bone, a third organ system, under the influence of in vitro Triton WR-133. This stimulation affects most major lipid classes. Triton similarly stimulates lipid synthesis in tissue cultures of bone cells. This is the first report of an effect of Triton on lipid synthesis (1) in bone and (2) in any tissue culture system.