Horizontal vestibulo-ocular reflexes in humans with only one horizontal semicircular canal.
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Humans↗
Biomedical subjects
C J Henderson
Publications and source records attributed to C J Henderson.
Perioperative respiratory therapy (PORT). A program of preoperative risk assessment and individualized postoperative care.
In an effort to contain the expense of respiratory therapy modalities as well as to provide the level of respiratory care most appropriate for postoperative patients, we devised a perioperative respiratory therapy program (PORT). We describe the response of 1,476 consecutive patients treated by our Respiratory Care Department prior to and during the first year of PORT. Surgical procedures were divided into ten categories. The PORT group had significantly lower cost than the non-PORT group in two of the categories, with a significantly higher cost in one. We describe the advantages of PORT, which were identified by participating surgeons, respiratory therapists, and patients. We present a simple, bedside, risk assessment form which enabled us to predict the risk of postoperative pulmonary complications and to provide more aggressive respiratory therapy interventions to higher-risk patients.
Costs and Cost Analysis↗
Contraceptive potential of antibodies to the zona pellucida.
The notion of a contraceptive vaccine based on gamete-specific surface antigens was first proposed over a decade ago, as the result of in-vitro and in-vivo studies, and in recent years has been the subject of intensive research. In particular, the zona pellucida has attracted much attention as a potential target for immunological intervention in the fertilization process. Such is the rapidly-expanding nature of research into the biochemical and biological characterization of this structure, that a review of the implications for the development of a contraceptive vaccine seems timely.
Antigens, Surface↗
Analysis of the biological properties of antibodies raised against intact and deglycosylated porcine zonae pellucidae.
Zonae pellucidae (ZP) were isolated from 1,500 porcine ovaries and heat solubilized to generate approximately 15 mg ZP glycoprotein. Analysis of this material by isoelectric focusing, one-dimensional electrophoresis, and gas chromatography indicated the presence of a major glycoprotein species that exhibited considerable microheterogeneity with respect to its charge (pI 7.5-3.5) and molecular mass (45-85 kDa) and that contained 39.6% carbohydrate, predominantly N-acetylglucosamine. Chemical deglycosylation of porcine ZP using trifluoromethanesulphonic acid (TFMS) resulted in the production of five discrete protein bands on one-dimensional sodium dodecyl sulphate/polyacrylamide gel electrophoresis (SDS/PAGE) with molecular masses of 66, 52, 36, 32, and 16 kDa. Antisera raised in rabbits and marmosets to ZP and/or deglycosylated ZP (DGZP) were used in immunoblotting experiments to demonstrate the retention of immunogenicity by DGZP and the cross-reactivity of the antisera with their heterologous antigen. These studies indicated that antisera that were capable of inhibiting the fertility of primates in vivo and the penetration of the human ZP in vitro reacted preferentially with 3 of the 5 products of deglycosylation, with molecular masses of 66, 52, and 36 kDa. Anti-DGZP antibodies were also shown to interact with intact porcine and human ZP and, with the latter, to block the ability of human spermatozoa to both bind to and penetrate this structure.
Animals↗
Polyclonal antibodies to a 32-kDa deglycosylated polypeptide from porcine zonae pellucidae will prevent human gamete interaction in vitro.
The major deglycosylated polypeptides of the porcine zona pellucida (ZP), with molecular masses of 66, 52, 36, and 32 kDa, were purified to homogeneity with one-dimensional sodium dodecyl sulphate/polyacrylamide gel electrophoresis (SDS/PAGE). Immunofluorescence studies demonstrated that antibodies to the DGZP fraction, and the 66- and 32-kDa polypeptides, bound predominantly to the outer ZP; however, only the first two of these antisera formed an immunoprecipitate around the outer human ZP. In immunoblotting experiments using polyclonal antisera raised to these molecules all four polypeptides exhibited cross-reactivity with each other and their parental glycoprotein families (ZP 1-4). In addition, the antisera were tested in an in vitro human gamete bioassay to determine their contraceptive potential; antibodies to the 32-kDa deglycosylated polypeptide inhibited human gamete interaction to the greatest extent, 5.3% (+/- 1.2%), relative to a control value of 100%.
Animals↗
Analysis of the surface labelling characteristics of human spermatozoa and the interaction with anti-sperm antibodies.
Washed ejaculated human spermatozoa were surface labelled with 125I, using solid phase (iodogen) or enzymic (lactoperoxidase) methods, while membrane components possessing terminal galactose or galactosamine residues were labelled with the galactose oxidase-sodium [3H]borohydride technique. All three procedures revealed the presence of 2 major labelled surface components. The first comprised a broad band of radioactivity migrating just behind the ion front on SDS-PAGE, which could be extracted with chloroform and methanol, suggesting a lipid-like composition. The second fraction exhibited properties consistent with a major glycoprotein component of the human sperm plasma membrane, giving a peak of radioactivity with Mr = 20,000, within which a discrete doublet of bands (Mr = 17,000 and 19,000) could be resolved by autoradiography. A more detailed analysis of the labelled protein fraction after TCA precipitation revealed a number of other surface components, the major ones of which exhibited Mr values of 30,000, 45,000, 66,000, 115,000 and 160,000. Western blot analysis was then used to determine whether any of the surface components described above interacted with the gamma-globulin fraction of antisera obtained from patients exhibiting idiopathic autoimmunity against sperm antigens. Using a purified membrane preparation as the target, antibodies were detected against numerous high molecular weight bands with Mr values similar to the major components of the human sperm surface (35,000, 45,000, 66,000, 90,000 and 150,000). The nature of the antigens targeted by these antisera did not correlate with the ability of the latter to stimulate or suppress sperm-oocyte fusion.
Autoantibodies↗
Purification of bile acid-binding proteins from rat hepatic cytosol. Use of a photoaffinity label to detect novel Y' binders.
A 125I-labelled photolabile derivative of cholic acid has been used to investigate the organic anion-binding Y' fraction from rat liver, prepared by the method of Sugiyama, Y., Yamada, T. and Kaplowitz, N. (1982) Biochimica Biophysica Acta, 709, 342-352. The use of this photoaffinity probe led to the discovery of previously undescribed bile acid-binding proteins. A comprehensive purification scheme for the Y' proteins which allows the isolation of these novel binding species is described. Electrophoretic analysis shows that the Y' binders can be divided into two groups. The proteins in group 1 are dimeric and the 5B, 6E and 7F binding species consist of subunits with approximate molecular masses of 19.6, 15.6 and 14.9 kDa, respectively. The group 2 binding proteins, 5C, 5D and 8C, are monomeric and have molecular masses of approximately 36.2, 36.2 and 33 kDa, respectively. Calculation of the incorporation of 125I by these proteins showed that the group 1 proteins displayed a significantly greater specific incorporation of radioactivity than group 2. The specificity of 125I-labelled 3 beta-azidocholylhistamine is further demonstrated by analysis of tryptic digests of photoaffinity labelled Y' binders and glutathione S-transferases AA, A, D and F by reverse-phase high-performance liquid chromatography (HPLC) and thin-layer chromatography (TLC). The majority of the radioactivity was shown to be incorporated into a single component, which was not coincident with the free photoaffinity label.
Affinity Labels↗
Synthesis and characterisation of an iodinated bile-salt derivative for photoaffinity labelling.
The synthesis and characterisation of a novel iodinated bile salt derivative, 125I-labelled 3 beta-azidocholylhistamine, is described. The derivative is handled by rat liver in a similar manner to taurocholate and binding to bovine serum albumin, a well-characterised bile acid-binding protein, is demonstrated. The suitability of the derivative for photoaffinity labelling is assessed.
Affinity Labels↗
Thyroid status in patients with chronic renal failure.
Serum thyroid hormone concentrations have been measured in 21 patients with chronic renal failure, treated conservatively and compared with values from 19 control subjects. Many patients had serum total T3 and T4 concentrations below the reference ranges. The concentrations of free T4 and free T3 and the free thyroxine index were significantly lower in patients with abnormal total concentrations of the thyroid hormones than in the controls. Both the free and the total concentrations of T4 correlated inversely with the degree of renal failure. The concentration of thyroxine binding globulin (TBG), fell within the reference range in each of the patients, but was significantly lower in the patient group when compared with the controls. These TBG concentrations, however, were not sufficiently decreased to explain the low total thyroid hormone concentrations found in the patients. The affinity of TBG for T4 and T3 in the patient and control groups was not significantly different. The TSH response to TRH was diminished in many of the patients, but the measurement of other pituitary hormones indicated that pituitary function was normal in these patients. The possible mechanisms responsible for the changes observed in thyroid and pituitary hormones are discussed.
Adolescent↗
Does antibiotic spray reduce wound infection?
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Abdomen↗
The localization of equivalent dipoles of EEG sources by the application of electrical field theory.
A technique is described for finding the position, magnitude and orientation of the equivalent electrical dipole of EEG activity given the pattern of potential differences recorded at the scalp. The technique is based on an iterative computer program implementing equations describing the electrical field of a dipole in a spherical conductor. The computer program was tested in vitro against data obtained from an inert spherical conductor (a bowl containing physiological saline, fitted with recording electrodes and a movable dipole) and an anisotropic conductor (a similarly equipped human skill including a simulated scalp). In both practical models, the computer program accurately located the dipole, the mean differences between observed and computed loci being of the order of 1 cm at widely different locations. This accuracy was maintained in the anisotropic model even though potentials transmitted through the skill were attenuated by 80%. In vivo, the program successfully located the equivalent generator of blink artefacts within the remaining eye of a one-eyed subject and, in a normal subject, localized the dipole of corresponding potentials to a midline inter-ocular position. In further investigation of normal subjects, the distribution of amplitudes at latencies within Wave V of the visual evoked response confirmed the loci of equivalent generators within posterior cerebral regions. The technique was also applied to the alpha rhythm indicating a posterior locus compatible with the view that alpha rhythm is generated chiefly by posterior cerebral cortex. Factors affecting the accuracy of the technique and the limitations of one-dipole models are discussed.
Action Potentials↗
The influence of knife dullness on poultry processing operator exertions and the effectiveness of periodic knife steeling.
A novel procedure is described to establish knife steeling schedules for poultry and meat- processing operations based on increased force due to knife dullness from repetitive use to minimize operator exertions and physical stress associated with work-related musculoskeletal disorders. Knife dullness was quantified using a novel apparatus described in this article that measures the area cut by a knife into a carrageenan gel target for a controlled dynamic load at the knife handle. Two meat-cleaning jobs in a poultry-processing plant were studied. One job required significantly more force and a greater number of cuts than the other. Eight experienced operators participated in the study. Four freshly ground and honed knives were randomly used by each operator for 4, 45, 75, or 125 cutting cycles, measured for dullness and reconditioned by the operator using a steel sharpening rod. An empirical model for knife dulling and reconditioning was developed, and the corresponding increase in force was predicted for various cutting and reconditioning frequencies. The model showed that it took 57 and 125 cutting cycles for the high- and low-force jobs, respectively, to achieve a similar reduction in target surface area of 30%. This reduction in target surface area corresponded to a similar percentage increase in force needed for the same cut in carrageenan gel as compared to a freshly honed knife as measured using strain gages. This method may be used in meat processing plants for determining effective reconditioning schedules that reduce operator exertions with minimum effect on quality and productivity.
Adult↗
Progression of collagenous colitis to ulcerative colitis.
Collagenous colitis is a form of microscopic colitis that results in chronic watery diarrhea. The disorder predominantly affects middle-aged women, and its course tends to be benign. It is not thought to be a precursor of overt inflammatory bowel disease; however, apparent progression to ulcerative colitis has been reported on one previous occasion. We describe two further patients with symptoms and histologic features of collagenous colitis who subsequently developed ulcerative colitis. The first patient developed ulcerative colitis 13 months after diagnosis of collagenous colitis, although she gave a 23-year history of profuse watery diarrhea, which had not been adequately investigated. In the second patient, collagenous colitis was diagnosed soon after the onset of watery diarrhea, and 12 months later, progression to ulcerative colitis was documented. Both patients tested positive for perinuclear antineutrophil cytoplasmic antibody after they developed ulcerative colitis; the first patient was initially negative. In conclusion, these two cases, in addition to the one other in the literature, suggest that collagenous colitis and ulcerative colitis may represent extremes in the spectrum of inflammatory bowel disease and that collagenous colitis may evolve to ulcerative colitis. Therefore, progression to ulcerative colitis should be considered in any patient with known collagenous colitis whenever bloody diarrhea occurs, or if red cells, as well as white cells, are noted on stool microscopy.
Aged↗
Head impulses after unilateral vestibular deafferentation validate Ewald's second law.
To determine the relative contributions of ampullofugal (AF) and ampullopetal (AP) stimulation of the horizontal semicircular canal (HSCC) to the horizontal vestibulo-ocular reflex (HVOR), 12 patients were studied 1 year after total unilateral vestibular deafferentation (UVD). Compensatory eye movement responses to impulses of horizontal head rotation were studied using magnetic search coils. The head impulses were rapid (up to 3000 deg/sec/sec) passive, unpredictable, step displacements of horizontal angular head position with respect to the trunk. The results from these 12 patients were compared with results from 30 normal subjects. An HVOR deficit was found to each side. The HVOR in response to head impulses toward the deafferented side, a response generated exclusively by ampullofugal stimulation of the single functioning HSCC, was severely deficient with an average gain of 0.25; the HVOR in response to head impulses toward the intact side, a response generated exclusively by ampullopetal stimulation of the single functioning HSCC, was mildly but significantly deficient compared with normal subjects. These results show that rapid, unpredictable head movements, unlike slow, predictable head movements, do demonstrate the AP-AF HVOR asymmetry, which could be expected from consideration of the behavior of single vestibular afferent neurons, an asymmetry that is expressed by Ewald's 2nd Law.
Eye Movements↗