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PubMed1974

Computerized transaxial x-ray tomography of the human body.

The ACTA-Scanner has virtually unlimited potential in the evalution of any part of the body. The usefulness of the technique has already been shown in the appraisal of pathologies of the brain and cerebrospinal fluid cavities. The orbits and the eyeballs, the facial sinuses, and skull base lesions have also been elucidated. Tumors of the larynx, pharynx, thyroid, and parathyroid; lymphomas; and pathology of the spine and spinal cord are well within the reach of this new diagnostic methodology. Lung pathologies, such as emphysema, pneumonias, neoplasms, infarctions, pleural effusions and granulomatous diseases, and mediastinal pathology represent a challenging complex of lesions to be appraised by ACTA-scanning. For the heart, there is great potential for observing cardiac chamber size, hypertrophy of ventricular or atrial walls, and ventricular or aortic aneurysms, and possibly for recognizing the damaged myocardial tissue immediately after or some time after an infarction. The abdominal pathologies that can be studied are almost uncountable: gastric neoplasms, pancreatic cysts and stones, gallstones, neoplasms of the liver and pancreas, bowel tumors, abdominal aortic aneurysms, renal neoplasms and cysts, atrophy of the kidneys, bladder tumors, uterine tumors, ovarian cysts, and many more. Although bones and joints are adequately demonstrated by conventional x-ray techniques, there is no doubt that as the new technique is developed ACTA-grams will contribute significant information in the transverse plane, as well as in densitometric analyses. The impact of ACTA-scanning will not be limited to the diagnostic area, but will extend, at least indirectly, to general patient management and to some aspects of medical economics as well. Risk-laden, technically complex, and costly diagnostic procedures, sometimes requiring lengthy hospitalization, will in some cases be eliminated. The simple, innocuous, and noninvasive ACTA-scanning can be performed on an outpatient basis. Repeated follow-up examinations should be easily accepted by the patients, considering that this diagnostic test is carried out without discomfort. The entire field of diagnostic radiology is on the verge of revolutionary changes.

Brain↗
PubMed2001

Functional nanoscale electronic devices assembled using silicon nanowire building blocks.

Because semiconductor nanowires can transport electrons and holes, they could function as building blocks for nanoscale electronics assembled without the need for complex and costly fabrication facilities. Boron- and phosphorous-doped silicon nanowires were used as building blocks to assemble three types of semiconductor nanodevices. Passive diode structures consisting of crossed p- and n-type nanowires exhibit rectifying transport similar to planar p-n junctions. Active bipolar transistors, consisting of heavily and lightly n-doped nanowires crossing a common p-type wire base, exhibit common base and emitter current gains as large as 0.94 and 16, respectively. In addition, p- and n-type nanowires have been used to assemble complementary inverter-like structures. The facile assembly of key electronic device elements from well-defined nanoscale building blocks may represent a step toward a "bottom-up" paradigm for electronics manufacturing.

Journal Article↗
PubMed1988

Stabilities of lyophilized Staphylococcus aureus typing bacteriophages.

Staphylococcus aureus bacteriophages (25 phages) were lyophilized in aliquots 12 to 18 years ago and stored in vacuo at -20 degrees C. Eight viruses each lost one log titer, while seventeen retained the original titers. The use of lyophilized phages provided more reproducible phage typing and reduced by 75% the complexity and cost. This important test is thus made feasible for more laboratories.

Bacteriophage Typing↗
PubMed2000

Rapid diagnosis of bacteremia by universal amplification of 23S ribosomal DNA followed by hybridization to an oligonucleotide array.

The rapid identification of bacteria in blood cultures and other clinical specimens is important for patient management and antimicrobial therapy. We describe a rapid (<4 h) detection and identification system that uses universal PCR primers to amplify a variable region of bacterial 23S ribosomal DNA, followed by reverse hybridization of the products to a panel of oligonucleotides. This procedure was successful in discriminating a range of bacteria in pure cultures. When this procedure was applied directly to 158 unselected positive blood culture broths on the day when growth was detected, 125 (79.7%) were correctly identified, including 4 with mixed cultures. Nine (7.2%) yielded bacteria for which no oligonucleotide targets were present in the oligonucleotide panel, and 16 culture-positive broths (10.3%) produced no PCR product. In seven of the remaining eight broths, streptococci were identified but not subsequently grown, and one isolate of Staphylococcus aureus was misidentified as a coagulase-negative staphylococcus. The accuracy, range, and discriminatory power of the assay can be continually extended by adding further oligonucleotides to the panel without significantly increasing complexity or cost.

Bacteremia↗
PubMed2005

Identification of medically important molds by an oligonucleotide array.

Infections caused by fungi have increased in recent years. Accurate and rapid identification of fungal pathogens is important for appropriate treatment with antifungal agents. On the basis of the internal transcribed spacer 1 (ITS 1) and ITS 2 sequences of the rRNA genes, an oligonucleotide array was developed to identify 64 species (32 genera) of clinically important filamentous (or dimorphic) fungi. These 64 species included fungi causing superficial, cutaneous, subcutaneous, and invasive infections. The method consisted of PCR amplification of the ITS regions using a pair of universal primers, followed by hybridization of the digoxigenin-labeled PCR products to a panel of species- or group-specific oligonucleotides immobilized on a nylon membrane. Of 397 fungal strains (290 target and 107 nontarget strains) tested, the sensitivity and specificity of the array was 98.3% (285/290) and 98.1% (105/107), respectively. Misidentified strains were usually those belonging to the same genus of the target species or having partial homology with oligonucleotide probes on the membrane. The whole procedure can be finished within 24 h starting from isolated colonies; reproductive structures, which are essential for the conventional identification methods, are not needed. In conclusion, the present array is a powerful tool for identification of clinically important filamentous fungi and may have the potential to be continually extended by adding further oligonucleotides to the array without significantly increasing the cost or complexity.

Fungi↗
PubMed1979

Survival of anaerobic bacteria in common laboratory diluents.

The survival of six species of anaerobic bacteria was studied in simple or commercially available diluents. Bacteroides fragilis and Fusobacterium nucleatum showed excellent survival in all diluents including distilled water. Fusobacterium mortiferum survived well in all diluents except water and water supplemented with 0.1% gelatain. Clostridium perfringens survived best in phosphate-buffered saline with gelatin. Peptococcus asaccharolyticus required gelatin added to the basic diluent, and Streptococcus intermedius showed excellent survival only in minimal essential medium with gelatin. These diluents could provide effective and economical alternatives to more complex and costly diluents often used in work with anaerobic bacteria.

Anaerobiosis↗
PubMed1985

Quantitative assessment of the mucosal architecture of jejunal biopsy specimens: a comparison between linear measurement, stereology, and computer aided microscopy.

Fifty jejunal biopsy specimens obtained from normal subjects and from untreated and treated patients with coeliac disease were assessed blindly by three independent observers, each of them using different morphometric techniques-namely, linear measurement, stereology, and computer aided microscopy. In two of 26 control biopsy specimens linear measurement was not possible because of distortion of villi. Highly significant (p less than 0.001) correlation coefficients were found between the different techniques. With all methods significant differences between controls and patients with coeliac disease and between treated and untreated coeliac patients were found. Only by stereology, however, was there no overlap between results for patients and those for controls. In view of the limitations of linear measurement and the high cost and complexity of computer aided microscopy, we propose that a simple stereological technique using an eyepiece graticule is the method of choice in the quantitative assessment of mucosal architecture in jejunal biopsy specimens.

Biopsy↗
PubMed2001

Clinical studies on submicroscopic subtelomeric rearrangements: a checklist.

BACKGROUND: Submicroscopic subtelomeric chromosome defects have been found in 7.4% of children with moderate to severe mental retardation and in 0.5% of children with mild retardation. Effective clinical preselection is essential because of the technical complexities and cost of screening for subtelomere deletions. METHODS: We studied 29 patients with a known subtelomeric defect and assessed clinical variables concerning birth history, facial dysmorphism, congenital malformations, and family history. Controls were 110 children with mental retardation of unknown aetiology with normal G banded karyotype and no detectable submicroscopic subtelomeric abnormalities. RESULTS: Prenatal onset of growth retardation was found in 37% compared to 9% of the controls (p<0.0005). A higher percentage of positive family history for mental retardation was reported in the study group than the controls (50% v 21%, p=0.002). Miscarriage(s) were observed in only 8% of the mothers of subtelomeric cases compared to 30% of controls (p=0.028) which was, however, not significant after a Bonferroni correction. Common features (>30%) among subtelomeric deletion cases were microcephaly, short stature, hypertelorism, nasal and ear anomalies, hand anomalies, and cryptorchidism. Two or more facial dysmorphic features were observed in 83% of the subtelomere patients. None of these features was significantly different from the controls. Using the results, a five item checklist was developed which allowed exclusion from further testing in 20% of the mentally retarded children (95% CI 13-28%) in our study without missing any subtelomere cases. As our control group was selected for the "chromosomal phenotype", the specificity of the checklist is likely to be higher in an unselected group of mentally retarded subjects. CONCLUSIONS: Our results suggest that good indicators for subtelomeric defects are prenatal onset of growth retardation and a positive family history for mental retardation. These clinical criteria, in addition to features suggestive of a chromosomal phenotype, resulted in the development of a five item checklist which will improve the diagnostic pick up rate of subtelomeric defects among mentally retarded subjects.

Abnormalities, Multiple↗
PubMed2004

Applications of positron emission tomography (PET) in neurology.

Positron emission tomography (PET) is a powerful imaging technique which enables in vivo examination of brain functions. It allows non-invasive quantification of cerebral blood flow, metabolism, and receptor binding. In the past PET has been employed mainly in the research setting due to the relatively high costs and complexity of the support infrastructure, such as cyclotrons, PET scanners, and radiochemistry laboratories. In recent years, because of advancements in technology and proliferation of PET scanners, PET is being increasingly used in clinical neurology to improve our understanding of disease pathogenesis, to aid with diagnosis, and to monitor disease progression and response to treatment. This article aims to provide an overview of the principles of PET and its applications to clinical neurology.

Brain↗
PubMed1975

Federal and state pesticide regulations and legislation.

The combined research, education, and regulatory efforts of federal and state governments have made possible an impressive record of abundant production while imposing minimal harm to human health and the environment. Considering that approximately one billion pounds of pesticides are being applied in the United States annually to control about 2000 pest species, the safety record is remarkable. The increased public concern about environmental values and long-term health effects is constructive and is resulting in some of the regulatory changes discussed in this article. The Federal Environmental Pesticide Control Act can result in an improved and expanded joint effort by federal and state governments to limit the misuse of pesticides while permitting their use to facilitate increased production of food, feed, and fiber; provide protection from spoilage; improve health; and control nuisance insects and unwanted plants. Implementation of current regulations, plus those in the process of being enacted under authority of the new federal act, will be complex and costly. Regulations will control the registration, labeling, distribution, storage, use and application, and disposal of pesticides. A small segment of our society would like to have the use of all chemicals banned. A few individuals oppose all government controls. However, the vast majority of agricultural producer groups, representatives of industry, and the public support the need for pesticide regulations. Only through continued legal controls over pesticides may we hope to retain their use. Our society has gained tremendous benefits from the use of pesticides to prevent disease and to increase the production of food and fiber. Our need to use pesticides will continue to increase for the foreseeable future. Government agencies responsible for protecting human health and the environment must make sound judgments on an individual basis in evaluating the evidence concerning both the benefits and risks of using pesticides.

Government Agencies↗
PubMed2000

Lower limb skeletal muscle mass: development of dual-energy X-ray absorptiometry prediction model.

Although magnetic resonance imaging (MRI) can accurately measure lower limb skeletal muscle (SM) mass, this method is complex and costly. A potential practical alternative is to estimate lower limb SM with dual-energy X-ray absorptiometry (DXA). The aim of the present study was to develop and validate DXA-SM prediction equations. Identical landmarks (i.e., inferior border of the ischial tuberosity) were selected for separating lower limb from trunk. Lower limb SM was measured by MRI, and lower limb fat-free soft tissue was measured by DXA. A total of 207 adults (104 men and 103 women) were evaluated [age 43 +/- 16 (SD) yr, body mass index (BMI) 24.6 +/- 3.7 kg/m(2)]. Strong correlations were observed between lower limb SM and lower limb fat-free soft tissue (R(2) = 0.89, P < 0.001); age and BMI were small but significant SM predictor variables. In the cross-validation sample, the differences between MRI-measured and DXA-predicted SM mass were small (-0.006 +/- 1.07 and -0.016 +/- 1.05 kg) for two different proposed prediction equations, one with fat-free soft tissue and the other with added age and BMI as predictor variables. DXA-measured lower limb fat-free soft tissue, along with other easily acquired measures, can be used to reliably predict lower limb skeletal muscle mass.

Absorptiometry, Photon↗
PubMed2005

Pooling samples within microarray studies: a comparative analysis of rat liver transcription response to prototypical toxicants.

Combining or pooling individual samples when carrying out transcript profiling using microarrays is a fairly common means to reduce both the cost and complexity of data analysis. However, pooling does not allow for statistical comparison of changes between samples and can result in a loss of information. Because a rigorous comparison of the identified expression changes from the two approaches has not been reported, we compared the results for hepatic transcript profiles from pooled vs. individual samples. Hepatic transcript profiles from a single-dose time-course rat study in response to the prototypical toxicants clofibrate, diethylhexylphthalate, and valproic acid were evaluated. Approximately 50% more transcript expression changes were observed in the individual (statistical) analysis compared with the pooled analysis. While the majority of these changes were less than twofold in magnitude ( approximately 80%), a substantial number were greater than twofold (approximately 20%). Transcript changes unique to the individual analysis were confirmed by quantitative RT-PCR, while all the changes unique to the pooled analysis did not confirm. The individual analysis identified more hits per biological pathway than the pooled approach. Many of the transcripts identified by the individual analysis were novel findings and may contribute to a better understanding of molecular mechanisms of these compounds. Furthermore, having individual animal data provided the opportunity to correlate changes in transcript expression to phenotypes (i.e., histology) observed in toxicology studies. The two approaches were similar when clustering methods were used despite the large difference in the absolute number of transcripts changed. In summary, pooling reduced resource requirements substantially, but the individual approach enabled statistical analysis that identified more gene expression changes to evaluate mechanisms of toxicity. An individual animal approach becomes more valuable when the overall expression response is subtle and/or when associating expression data to variable phenotypic responses.

Animals↗
PubMed2004

The role of bisphosphonates in the management of advanced cancer with a focus on non-small-cell lung cancer. Part 1: Mechanisms of action, role of biomarkers and preclinical applications.

With recent advances in cancer management, patients with metastatic bone disease are likely to have a prolonged clinical course, with skeletal-related events such as pain, hypercalcemia, pathologic fractures, spinal cord and nerve compression. Bisphosphonate use has resulted in the reduction of skeletal-related complications for a number of tumors including breast, prostate and myeloma, and improvements in the quality of life for patients. There is now evidence that newer, highly potent, nitrogen-containing bisphosphonates reduce skeletal complications in patients with bone metastases from other solid tumors (including lung cancer). The early identification of patients at high risk for developing bone metastases may help curtail a complex and costly clinical problem--skeletal-related events. In this article, we review the different mechanisms of bisphosphonates and the potential role of newer-generation bisphosphonates, such as zoledronic acid, in the management of advanced, metastatic bone disease. We include a review of mechanistic studies and preclinical data. Additionally, the utility of evolving concepts such as bone markers and imaging of bone metastases are discussed.

Antineoplastic Agents↗
PubMed1994

PET and SPECT in epilepsy.

Positron emission tomography (PET) measures regional cerebral metabolism and blood flow. PET imaging has been quite successful in identifying focal epileptogenesis as an area of hypometabolism between attacks. PET has proven to be an important diagnostic tool in selecting patients with partial epilepsy, in particular with foci in the temporal lobe, for resective surgery. Because of the high costs and complexities of PET, this technology has been confined to a limited number of centers. Single photon emission computed tomography (SPECT) can also be used for noninvasive functional imaging of the brain because it demonstrates regional cerebral blood flow which is linked to cerebral metabolism. SPECT uses conventional and readily available equipment and radiopharmaceuticals. Emphasizing the outstanding UCLA experience with PET, the presently available data on the usefulness of these functional imaging techniques in the context of surgical treatment of the epilepsies are reviewed.

Adult↗
PubMed1987

Standardization in the measurement of left ventricular wall mass. Two-dimensional echocardiography.

Two-dimensional echocardiography is superior to M-mode echocardiography for estimation of left ventricular mass when left ventricular shape is markedly abnormal. Left ventricular mass measurement by two-dimensional echocardiography depends on careful experimental calibration of the echocardiographic instrument using either a standard phantom or actual heart slices, and appropriate geometric algorithm, and short axis images to determine myocardial cross-sectional area. Several well-validated algorithms are available, of which the short-axis area-length technique is the simplest. In hypertensive heart disease, in which left ventricular shape is usually close to normal, two-dimensional echocardiography may offer a smaller standard error than M-mode, but this issue requires further evaluation. Further, it is uncertain whether the incremental accuracy of two-dimensional echocardiography in hypertensive heart disease would offset its increased cost and complexity relative to M-mode echocardiography.

Echocardiography↗
PubMed2005

Measuring accuracy of discharge diagnoses for a region-wide surveillance of hospitalized strokes.

BACKGROUND AND PURPOSE: Measuring the impact of stroke through population-based stroke registers is complex and costly. The aim of the present study is to assess the validity of hospital discharge diagnoses (all ages) and to estimate the total number of hospitalized stroke events in the Veneto region (Northeastern Italy, 4,500,000 inhabitants). METHODS: All discharges covering a 1-year period (1999) from Veneto hospitals with International Classification of Diseases, 9th Revision codes 342, 430 to 434, and 436 to 438 were identified. A stratified sample was extracted and submitted to retrospective clinical record review according to the World Health Organization MONItoring trends and determinants in CArdiovascular disease stroke project. Using the positive predictive value (PPV) for validated acute stroke of each code to adjust for inaccuracy of discharge diagnoses, an estimate of hospital strokes was obtained. RESULTS: 4015 admissions were reviewed. Codes 430, 431, 434, and 436 as primary diagnoses had the highest PPV, which sharply decreased in the other diagnostic levels. Code 342 also showed a high PPV. The probability of suspected events meeting the stroke definition increased with age and was highest for patients admitted to neurological wards and for fatal events. Overall 9400 strokes (first-ever and recurrent) were estimated to be hospitalized in 1999, with an attack rate of 208 per 100,000. CONCLUSIONS: Our data indicate that once validation studies are undertaken on a sample of all hospitalized events, hospital discharge records can provide a valuable source of information on the actual burden of strokes on hospital services.

Adult↗
PubMed2005

Synthesis and luminescence of ZnMgS:Mn2+ nanoparticles.

Efficient green emission from ZnMgS:Mn2+ nanoparticles prepared by co-doping Mg2+ and Mn2+ ions into ZnS lattices has been observed. The synthesis is carried out in aqueous solution, followed by a post-annealing process, thus showing the features of less complexity, low cost, and easy incorporation of dopants. In comparison with the emission of ZnS:Mn2+ nanoparticles, which is located generally around 590 nm, the photoluminescence of ZnMgS:Mn2+ nanoparticles is blue-shifted by 14 nm in wavelength, leading to the enhanced green emission. The X-ray diffraction, electron spin resonance, and pressure dependent photoluminescence measurements suggest that the change of the crystal field caused by Mg2+ ionic doping and the lower symmetry in the nanoparticles may account for the blue-shift of the photoluminescence. The ZnMgS:Mn2+ nanoparticles with 1% Mn2+ doping exhibit the strongest luminescence, which could potentially meet the requirements for the construction of green light emitting diodes.

Crystallization↗
PubMed2000

Correlation-based correction of sound velocity inhomogeneities using delta-sigma modulators.

Delta-sigma (deltasigma) modulator based beamformers have been proposed for high-quality ultrasonic imaging. Due to the high sampling rate and single bit data width, the cost and complexity of the receive beamformer can be significantly reduced. It was shown that with proper dynamic focusing controls, equivalent image quality could be achieved with an adequate signal-to-quantization noise ratio (SQNR). In this paper, deltasigma modulator based beamformers are used for correlation-based phase aberrations correction of sound velocity inhomogeneities in the body. It is shown that the correction can be efficiently implemented at a performance level similar to that of a conventional radio frequency (rf) beamformer. In addition, more than 6 dB contrast improvement is demonstrated. The different dynamic focusing techniques are also investigated in the context of phase aberration correction. It is shown that the single bit dynamic focusing approach does not affect the overall performance of phase aberration correction.

Electronics, Medical↗