Nitrous oxide levels in operating and recovery rooms of Iranian hospitals.

BACKGROUND: Nitrous oxide (N(2)O) is the oldest anesthetic in routine clinical use and its occupational exposure is under regulation by many countries. As studies are lacking to demonstrate the status of nitrous oxide levels in operating and recovery rooms of Iranian hospitals, we aimed to study its level in teaching hospitals of Tehran University of Medical Sciences. METHODS: During a 6-month period, we have measured the shift-long time weighted average concentration of N(2)O in 43 operating and 12 recovery rooms of teaching hospitals of Tehran University of Medical Sciences. RESULTS: The results show that the level of nitrous oxide in all hospitals is higher than the limits set by different countries and anesthetists are at higher risk of exposure. In addition, it was shown that installation of air ventilation could reduce not only the overall exposure level, but also the level of exposure of anesthetists in comparison with other personnel. CONCLUSION: The high nitrous oxide level in Iranian hospitals necessitates improvement of waste gas evacuation systems and regular monitoring to bring the concentration of this gas into the safe level.

Integrated circuit-based instrumentation for microchip capillary electrophoresis.

Although electrophoresis with laser-induced fluorescence (LIF) detection has tremendous potential in lab on chip-based point-of-care disease diagnostics, the wider use of microchip electrophoresis has been limited by the size and cost of the instrumentation. To address this challenge, the authors designed an integrated circuit (IC, i.e. a microelectronic chip, with total silicon area of <0.25 cm2, less than 5 mmx5 mm, and power consumption of 28 mW), which, with a minimal additional infrastructure, can perform microchip electrophoresis with LIF detection. The present work enables extremely compact and inexpensive portable systems consisting of one or more complementary metal-oxide-semiconductor (CMOS) chips and several other low-cost components. There are, to the authors' knowledge, no other reports of a CMOS-based LIF capillary electrophoresis instrument (i.e. high voltage generation, switching, control and interface circuit combined with LIF detection). This instrument is powered and controlled using a universal serial bus (USB) interface to a laptop computer. The authors demonstrate this IC in various configurations and can readily analyse the DNA produced by a standard medical diagnostic protocol (end-labelled polymerase chain reaction (PCR) product) with a limit of detection of approximately 1 ng/microl (approximately 1 ng of total DNA). The authors believe that this approach may ultimately enable lab-on-a-chip-based electrophoretic instruments that cost on the order of several dollars.

Miniaturized system for isotachophoresis assays.

We present an inexpensive hand-held device (240 g) that implements microchip isotachophoresis (ITP) with laser induced fluorescence (LIF) detection. This self-contained instrument integrates the functionality required for high voltage generation onto a microelectronic chip, includes LIF detection and is powered by a universal serial bus (USB) link connected to a laptop computer. Using this device we demonstrate focusing and detection of a fluorescent species with a limit of detection of 100 pM. We show that the response of the detector is linear with the initial analyte concentration, making this device suitable for quantitative analysis. We also demonstrate the use of our simulation tools for design and prediction of ITP assays, and validate these results with a demonstration of multiplexed indirect detection of (unlabeled) analytes performed using the device. We find good agreement between simulations and experimental results. Using a label-free isotachaphoresis assay implemented in the hand-held device we detect two explosives and an endocrine disruptor spiked in river water, with no prior sample processing.

A scalable and modular lab-on-a-chip genetic analysis instrument.

We demonstrate a new and extremely inexpensive, multipurpose desktop system for operating lab-on-a-chip (LOC) devices. The system provides all of the infrastructure necessary for genetic amplification and analysis, with orders of magnitude improvement in performance over our previous work. A modular design enables high levels of integration while allowing scalability to lower cost and smaller size. The component cost of this system is ca. $600, yet it could support many diagnostic applications. We demonstrate an implementation of genetic amplification via polymerase chain reaction (PCR), and analysis using capillary electrophoresis (CE). The PCR is able to amplify from single or several copies of target DNA and the CE performance (e.g. sensitivity) is comparable to that of commercial photomultiplier-based confocal lab-on-chip instrumentation. We believe this demonstrates that the cost of infrastructure need no longer be a barrier to the wide-spread application of LOC technologies in healthcare and beyond.

Inexpensive, universal serial bus-powered and fully portable lab-on-a-chip-based capillary electrophoresis instrument.

Capillary electrophoresis is a cornerstone of lab-on-a-chip (LOC) implementations for medical diagnostics. However, the infrastructure needed to operate electrophoretic LOC implementations tends to be large and expensive, hindering the development of portable or low-cost systems. A custom-designed and highly integrated microelectronic chip for high-voltage generation switching and interfacing is recently developed. Here, the authors integrate the microelectronic chip with a microfluidic chip, a solid-state laser, filter, lens and several dollars worth of electronic components to form an inexpensive and portable platform, which is the size of a mobile telephone. This compact system has such reduced power requirements that the complete platform can be operated using a universal serial bus link to a computer. It is believed that this system represents a significant advancement in practical LOC implementations for point-of-care medical diagnostics.

High-Voltage CMOS Controller for Microfluidics.

A high-voltage microfluidic controller designed using DALSA semiconductor's 0.8-mum low-voltage/high-voltage complementary metal-oxide semiconductor/double diffused metal-oxide semiconductor process is presented. The chip's four high-voltage output drivers can switch 300 V, and the dc-dc boost converter can generate up to 68 V using external passive components. This integrated circuit represents an advancement in microfluidic technology when used in conjunction with a charge coupling device (CCD)-based optical system and a glass microfluidic channel, enabling a portable and cost-efficient platform for genetic analysis.

An integrated CMOS high voltage supply for lab-on-a-chip systems.

Electrophoresis is a mainstay of lab-on-a-chip (LOC) implementations of molecular biology procedures and is the basis of many medical diagnostics. High voltage (HV) power supplies are necessary in electrophoresis instruments and are a significant part of the overall system cost. This cost of instrumentation is a significant impediment to making LOC technologies more widely available. We believe one approach to overcoming this problem is to use microelectronic technology (complementary metal-oxide semiconductor, CMOS) to generate and control the HV. We present a CMOS-based chip (3 mm x 2.9 mm) that generates high voltages (hundreds of volts), switches HV outputs, and is powered by a 5 V input supply (total power of 28 mW) while being controlled using a standard computer serial interface. Microchip electrophoresis with laser induced fluorescence (LIF) detection is implemented using this HV CMOS chip. With the other advancements made in the LOC community (e.g. micro-fluidic and optical devices), these CMOS chips may ultimately enable 'true' LOC solutions where essentially all the microfluidics, photonics and electronics are on a single chip.

Critical care issues in lung and heart transplantation.

Although much has been accomplished in HTx and LTx in the past few decades, much remains to be conquered. It is an ever-changing, always fascinating field. Though science and technology know no limits, the primary limitation of HTx and LTx continues to be the availability of donor organs. One can only hope that further advances in educating the public will help close the large gap between the list of those waiting and the organs available for transplantation.

Atomic force microscopy imaging of the human trigeminal ganglion.

This paper describes an investigation of gangliocytes via imaging semithin sections of two human trigeminal ganglia with an atomic force microscope (AFM). Whereas semithin sections are usually employed for transmission electron microscopy, we adopted this special type of sample preparation for our AFM studies to extract topographical data from the gangliocyte itself and from the nucleus, the nucleolus, the crystal-arranged lipofuscin granules, and the cell-surrounding mantle cells; simultaneously we characterized the samples with error signal mode. This AFM-related technique revealed no information concerning friction force and elasticity due to the presence of the embedding material (epoxy), but it gave additional topographical contrast. These are the first images of the human trigeminal ganglion by AFM.

Comparative analysis of two-dimensional protein patterns in malignant and normal human breast tissue.

Malignant and normal human breast tissue were compared by evaluating two-dimensional polyacrylamide gel electrophoresis (2D-PAGE) maps of frozen tissue samples. Image analyzing software was used to scan and process 34 gels. Eight (8/34) of these gels (4 malignant breast tumor samples, 4 normal tissue samples) were selected on the basis of gel and image quality to build a database to identify and measure the expression of a previously unidentified proteome. Growth factor receptor proteins (GFRs), including ERBB2 (HER2) and ERBB3 (HER3), were expressed in the malignant tissue samples. Growth factor receptor proteins were not expressed in the normal tissue. Also, expression of PS2-protein (pS2) was detected in neither malignant nor normal tissue. In benign breast samples a higher intensity of protein expression could be observed for maspin, desmoglein 3 and keratin 8 than in malignant samples. Other proteins expressed in malignant breast tissue include mitogen-activated protein kinase 3 (MK03), heat shock protein 27 kDa (HS27), growth factor receptor-bound protein (GRB2), cathepsin D, G1/S specific cyclin E1 (CGEI), glucose transporter type 5 (GTR5), and a number of as yet unidentified proteins.

Changes of biochemical and biomechanical properties in Dupuytren disease.

BACKGROUND: The major biochemical characteristic of Dupuytren disease is the progressive and irreversible deposition of excess fibrous collagen characterized by an enhanced type III collagen proportion. OBJECTIVE: To investigate the influence of changes of the collagen spectrum on the biophysical properties of the palmar aponeurosis. DESIGN: Variably affected palmar regions from 30 individuals with Dupuytren disease were classified according to histologic test results and clinical stage. Biochemical, biomechanical, and thermal contracture studies were performed. RESULTS: The relative type III collagen content increased with increasing tissue involvement and was found to correlate with calorimetric and biomechanical properties with the exception of the Young modulus. In experiments on the thermal isometric contracture, the collagen denaturation temperature decreased with increasing type III collagen content, ie, increasing involvement. To study the dependence of biophysical properties from the collagen type distribution independent of structural changes, as seen in Dupuytren disease, we investigated rat skins from animals of an age range characterized by dramatic changes in type III collagen content (0-18 months). Biomechanical data also correlated significantly with type III collagen content in rat skin with the exception of the time constant of stress relaxation. CONCLUSION: In light of these results, we suggest that structural changes, such as reduced collagen fibril diameters, associated with alterations in the type III collagen proportion may influence biophysical properties of connective tissues in the involved palmar aponeurosis in addition to alterations of the cross-linking pattern.

Rare variant of the brachial artery: superficial lateral inferior type VII EAB.

This study concerns a variant of the brachial artery with a modified origin and course. The artery was studied in 418 upper limbs removed from cadavers. In one upper limb the left brachial artery bifurcated into: (1) a superficial brachial a. (the variant) crossing superficially to the bicipital aponeurosis in the cubital region and assuming the course, position, and supply area of the radial artery, and (2) the deep brachial a. (another variant). An embryologic interpretation of this anomaly is based on a variant vascular development derived from the eighth intersegmental artery. The variant is termed according to Adachi's classification schedule as arteria brachialis superficialis lateralis inferior Type VII with the addition EAB (epiaponeurosis bicipitalis, i.e., superficial to the bicipital aponeurosis). Accurate information concerning unusual patterns of the arteries in the upper limbs is clinically relevant, especially in the avoidance of accidental intra-arterial injection with reflectory vascular occlusion leading to necrosis.

Comparison of palmar aponeuroses from individuals with diabetes mellitus and Dupuytren's contracture.

It is well known that Dupuytren's contracture is often associated with diabetes mellitus. Palmar fascia from individuals with diabetes mellitus and/or Dupuytren's contracture as well as controls were subjected to differential scanning calorimetry, biomechanical and biochemical analysis. The collagen denaturation temperature of the palmar aponeurosis from individuals with diabetes mellitus in the presence (71.0 degrees C) or absence of Dupuytren's contracture (70. 6 degrees C) was increased as compared with controls (68.5 degrees C), while this parameter was significantly reduced (about 3.5 degrees C) in contracture bands of Dupuytren's contracture. Stress relaxation experiments revealed that the viscous fraction was slightly reduced in diabetes mellitus (6.5%) vs. controls (8.3%), whereas in Dupuytren's contracture, irrespective of additional diabetes mellitus, a pronounced increase of this parameter was seen (36.5% vs. 24.5%) in the presence of diabetes mellitus. The time constants were significantly elevated by both disorders, this increase being more pronounced in Dupuytren's contracture. Taken together, these changes can be explained by increased cross-linking in diabetes mellitus, while in Dupuytren's contracture other structural changes, such as increased collagen type III content and loss of fascicular organization, play an additional role besides the finding of reduced cross linking.

Biomechanical stability of abductor pollicis longus muscles with variable numbers of tendinous insertions.

BACKGROUND: In the course of a study of different variants of the tendon of the abductor pollicis longus (APL) muscle, the unusual finding of a tendon with six subdivisions was observed in the first compartment. Using this preparation and others with various numbers of tendons (2, 3, 4, and 6), we intended to establish whether the multitendoned muscles increased the strength of the thumb. METHODS: Fifty-two upper extremities were examined with attention to the tendons of the APL muscle. The strain on each tendon was biomechanically determined using a microcomputer and potentiometer. The stress was measured continuously and plotted against strain. RESULTS: Following treatment with elastase, it is seen that the significance of changes in stability and Young's modulus is inversely proportional to the number of tendons arising from the APL. CONCLUSIONS: Division of the tendon into several parts leads to better mechanical distribution of stress and extension on thumb abduction. In addition, palmar-flexion in the wrist may be supported.

[Significance of fundus evaluation in the staging of hypertensive disease compared to electrocardiography and renal circulation]. / Bedeutung der Fundus-Beurteilung bei der Stadieneinteilung der Hochdruck-Krankheit im Vergleich zum Elektrokardiogramm und zur Nierendurchblutung.

In order to determine the relevance of ophthalmoscopic findings in cases of hypertension as compared to electrocardiographic abnormalities and disorders of the renal function, the authors examined 728 patients admitted to the German diagnostic Clinic (Wiesbaden) with hypertension over a period of 2 years. In all cases blood pressure was measured twice, and ophthalmoscopy, electrocardiography, a chest X-ray, and a laboratory checkup were performed. The effective renal plasma flow was measured in 100 cases using the 131 iodine-Hippuran clearance method. The results revealed that ophthalmoscopy is the most reliable method for classifying early and more advanced stages of hypertension, as compared to ECG and measurement of the effective renal plasma flow.