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Net charge and oxygen affinity of human hemoglobin are independent of hemoglobin concentration.

The dependence of net charge and oxygen affinity of human hemoglobin upon hemoglobin concentration was reinvestigated. In contrast to earlier reports from various laboratories, both functional properties of hemoglobin were found to be independent of hemoglobin concentration. Two findings indicate a concentration-independent net charge of carbonmonoxy hemoglobin at pH 6.6: (A) The pH value of a given carbonmonoty hemoglobin solution remains constant at 6.6 when the hemoglobin concentration is raised from 10 to 40 g/dl, indicating that there is no change in protonation of titratable groups of hemoglobin: (b) the net charge of carbonmonoxy hemoglobin as estimated from the Donnan distribution of 22Na+ shows no dependence on hemoglobin concentration in this concentration range. The oxygen affinity of human hemoglobin was determined from measurements of oxygen concentrations in equilibrated samples using a Lex-O2-Con apparatus (Lexington Instruments, Waltham, Mass.). P50 averaged 11.4 mm Hg at 37 degrees C, pH = 7.2, and ionic strength approximately 0.15. Neither P50 nor Hill's n showed any variation with hemoglobin concentrations increasing from 10 to 40 g/dl.

Electrophysiology↗

Fast measurements of transmission of erythema effective irradiance through clothing fabrics.

For efficiently measuring ultraviolet transmission through clothing materials for a large number of samples, an automated measuring system with a broad-band method has been built and calibrated against a spectroradiometer based instrument. The apparatus can be used to test 60 samples in 25 min. A selection of clothing materials of known composition, weave, color and state have been tested, using the broad band method and the automated measuring system together with a solar ultraviolet simulator. Variations of about eleven times for different weave structure, about two times in the ultraviolet transmittance for different colors, and about 20 times for some stretched samples were observed. For wet conditions, an increment in ultraviolet transmittance for cotton and lycra materials and a decrement for polyester and polyester(65%)/cotton(35%) were also observed.

Clothing↗

Effect of arachnoiditis on pain threshold.

A model for studying the relationship between chronic arachnoiditis and pain sensitivity was developed. Thirty male ICR mice were randomly divided into three groups and the tail-flick test was done using an EMDIE-TF6 apparatus (Emdie Instrument Co., Montpelier, VA). Ten mice were injected intrathecally with 5.0 microL of a kaolin-metrizamide mixture and ten control mice were injected intrathecally with 5.0 microL of an electrolyte solution resembling CSF. A third group, (naive controls) were given no treatment. Six weeks later tail-flick tests were repeated. The kaolin-treated mice had significantly decreased tail-flick latencies (P less than .05) compared with the baseline; the controls had no significant change in tail-flick latency. Histologic examination revealed moderate to severe arachnoiditis in the kaolin-treated animals and no evidence of arachnoid abnormalities in the controls. This study suggests that arachnoiditis may be associated with decreased pain thresholds.

Animals↗

A legacy of microneurosurgery: memoirs, lessons, and axioms.

This article is written at the request of the editor. It contains my autobiographical sketch, professional memories, lessons, axioms, and reflections on the present problems in neurodiagnosis and neurotherapy. The combination of microsurgical techniques, the bipolar coagulation technique, the concept of arachnoidal exploration, and the concept of segmental and compartmental occurrence of vascular and neoplastic lesions of the central nervous system, with their predilection sites, allowed microneurosurgery to gradually unfold and proceed within the last 30 years as a continuation of conventional neurosurgical principles established by the founder generation. Today, the lesions in each region of the central nervous system can be accessed without using computer-assisted targeting and navigation technology and can be selectively eliminated ("pure lesionectomy") with acceptable outcomes; the mortality and morbidity rates have been reduced remarkably. Further scientific and technological advances will promote the ongoing evolution in neurodiagnosis and neurotherapy. Competitive neurospecialties are welcomed in the interest of patients, medical sciences, and surgical advances. The younger generation of neurosurgeons will have spent more time in laboratory training, deepening their knowledge of neuroanatomy and gaining experience in surgical techniques. The achievements, limits, and problems of neurosurgery in relation to technology, medical and surgical standards, and controversial treatment options have been presented thoroughly in numerous professional publications. However, the relationship of neurosurgery to the evolution of integral neurophysiology and biochemistry has hitherto been inadequately evaluated. The advances in microbiology, anesthesiology, and topographic neurology have been viewed as essential components of neurosurgery's foundations. A critical analysis proves that this is only partially true. The turning point in the development from craniospinal surgery to physiological neurosurgery began with the research of Th. Kocher, V. Horsley, H. Cushing, and W. Dandy concerning the importance of the cerebrospinal fluid system. This was the first step in a trend toward integral neurophysiology, which initiated neurosurgical procedures on a routine basis. The intensive research on the hypothalamus by R.W. Hess and associates led to intensified studies on the autoregulated integral functional units of the central nervous system ("dynamic homeostasis," in the words of W.B. Cannon). This slowly developing but exciting history of neurophysiology requires patient study to seek out solutions for the present difficulties in neurodiagnosis and neurotherapy, which constitute a similar situation to that encountered by the pioneer surgeons at the end of the last century. In pertinent sections, my personal opinions relating to observations and experiences with a large number of operated patients with vascular and neoplastic lesions are presented. The predilection sites of brain tumors in the neopallial and paleopallial (limbic-paralimbic) areas and brainstem, and their expansive but usually not infiltrative growth, are discussed and documented. The current hypothesis of infiltrative growth of gliomas is opposed. The microsurgical technique for the treatment of various types of lesions is summarized. The principal microsurgical instruments and apparatus are presented with some remarks relating to their conception and manufacture.

History, 20th Century↗

In vivo continuous-wave optical breast imaging enhanced with Indocyanine Green.

We investigate the uptake of a nontargeted contrast agent by breast tumors using a continuous wave diffuse optical tomography apparatus. The instrument operates in the near-infrared spectral window and employs 16 sources and 16 detectors to collect light in parallel on the surface of the tumor-bearing breast (coronal geometry). In our protocol an extrinsic contrast agent, Indocyanine Green (ICG), was injected by bolus. Three clinical scenarios with three different pathologies were investigated. A two-compartment model was used to analyze the pharmacokinetics of ICG and preprocess the data, and diffuse optical tomography was used for imaging. Localization and delineation of the tumor was achieved in good agreement with a priori information. Moreover, different dynamical features were observed for differing pathologies. The malignant cases exhibited slower rate constants (uptake and outflow) compared to healthy tissue. These results provide further evidence that in vivo pharmacokinetics of ICG in breast tumors may be a useful diagnostic tool for differentiation of benign and malignant pathologies.

Adenocarcinoma↗

Revision of the anaesthetic aspects of an infection control policy following reporting of hepatitis C nosocomial infection.

Following the report by the N.S.W. Health Department of five cases of nosocomial hepatitis C infection allegedly caused by contaminated circuitry, a revision of the existing infection control policy was undertaken. Review of the existing policies of other organizations and the published scientific data in this area was the basis of the revision. The final policy as it pertains to anaesthesia requires universal precautions, disposal or decontamination and high level disinfection of instruments and apparatus that come into contact with patients or blood or body substances and protection of the breathing circuit by a filter with disposal or high-level disinfection of all parts of the circuit not so protected for every patient.

Anesthesiology↗

Rapid urinary iodide test.

Assessment of iodine deficiency and monitoring of iodine supplementation programs demand rapid, simple, and cost-effective methods for the determination of urinary iodide concentrations. We propose a semiquantitative rapid test, based on the iodide-catalyzed oxidation of 3,3',5,5'-tetramethylbenzidine by peracetic acid/H2O2, to yield colored products. The color of the chemical reaction is compared with color categories of a pictogram corresponding to three ranges: <100, 100-300, and >300 microg/L (<0.79, 0.79-2.36, and >2.36 micromol/L) of iodide concentrations. The test is very easy to perform and does not require any instrumentation or apparatus. Sample preparation is simple and consists of the removal of interfering substances by disposable columns, 65 x 10.5 mm, packed with purified activated charcoal. For comparison with a reference method for measuring urinary iodide, by high-performance liquid chromatography, we determined the iodide concentrations of 370 random (untimed) urine samples from consecutive patients by both high-performance liquid chromatography and the rapid test. The results obtained by both methods are in close agreement, with respect to classification of the samples according to the above three ranges, with a maximum difference of less than 5% for each range. Median (y) values of a given distribution of urinary iodide concentrations can be calculated from the percent (x) of samples below 100 microg/L (0.79 micromol/L) using the regression equation: y = 179.78 - 1.60x. This rapid test, therefore, is suited to epidemiological surveys of iodine deficiency, especially in developing countries.

Chromatography, High Pressure Liquid↗

[Problems of medical equipment terminology].

It is recommended to standardize the biomedical engineering terminology by making use of greek latin terminological elements. The designations of biomedical engineering products should include terms featuring the fundamental functions of their technical arrangements, viz. the type of action, the method of examination, the surgical manipulation, the kind of treatment, by retaining the already established clinical terms. The second part in the designation of the technical arrangement should carry the name of the organ, cavity, region and system of the organism, of the tissue, etc, for whose handling the instrument or apparatus is intended.

Medical Laboratory Science↗

[Artistic construction of medical equipment].

Through efforts of general designers, technologists and exterior feature designers of the Central Design planning-technological bureau "Medical Equipment" over 240 different pieces of medical apparatus and instruments have been created. The process of creating exterior design features includes collection and analysis of the information, compiling a survey note in which the purpose of the exterior designing and the present-day state of the prototypes of the object under consideration, as well as the possible unification of individual components and subassemblies are set forth. Medical requirements and limitations conditioned by the capabilities of the manufacturing plant are studied and the optimal demands as to the operation and use of the piece of equipment under construction are educed. In designing medical items, beside technical and service demands, and physiology are also taken into consideration. Great attention is paid to an effective method of compounding subassemblies and components, ensuring the technological rationale and unification of the most structural elements.

Biomedical Engineering↗

[An ophthalmologist's hints for organising medical help in remote areas of developing countries (author's transl)].

Judging by her experience gained in the south of Tunisia, the author suggests that instead of sending individual ophthalmologists to the developing countries it would be more advantageous to send mobile work teams in vehicles equipped with ophthalmological examination and surgical instruments and apparatus. This would be a suitable reply to the appeal made by the World Health Organization in 1973 for organising large-scale surgical treatment of cataracts with international participation within the framework of struggle against blindness in the world.

Developing Countries↗

Pseudoexfoliation syndrome and cataract surgery by phacoemulsification.

Pseudoexfoliation syndrome is a systemic age-related disease in which abnormal extracellular material is produced and accumulates in many ocular tissues. Its ocular manifestations involve all of the structures of the anterior segment as well as conjunctiva and orbital structures. The presence of pseudoexfoliation should alert the physicians to the increased risks associated during and after cataract surgery. Increasing awareness of this condition are important in the detection and preoperative determination of patients inclined to be at greater risk for complications during surgery. Data regarding the rate of complications during phacoemulsification suggest a lower complication rate than with exstracapsular extraction but still greater than in eyes without pseudoexfoliation. Despite the existence of a higher number of intraoperative and postoperative complications, experience with the phacoemulsification technique together with the improvement of the apparatus and instruments used enable similar results to obtained in eyes with pseudoexfoliation syndrome as in eyes without this pathology.

Cataract↗

[Means for administering radiation sources for interstitial radiation therapy].

The authors summed up foreign and Soviet literature data as well as their own clinical experience in the means of introducing radiation sources as one of the most important element of technical equipment of interstitial radiotherapy. They consist of means for the preparation of introducing sources, an instrument and appliances for introducing intrastats, an instrument and apparatus for introducing the sources. Pin-type sources with 60Co are taken as an example of meeting the requirements of means of introduction.

Brachytherapy↗