Real-time ultrasound for pregnancy diagnosis in the harbour seal (Phoca vitulina concolor).
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Animals↗
Biomedical subjects
J S Young
Publications and source records attributed to J S Young.
Cochlear IgG in the C3H/lpr autoimmune strain mouse.
The inner ear of the C3H/lpr autoimmune strain mouse was evaluated to identify potential mechanisms by which systemic autoimmune disease interferes with auditory function. The inner ears were immunohistochemically stained for IgG at ages before (2 months) and after (6-10 months) autoimmune disease onset and compared to age-matched nonautoimmune C3H/HeJ controls. Immunoreactivity for IgG was not seen in the 2 month C3H/lpr autoimmune mice or in either age group of the C3H/HeJ controls. On the other hand, all older C3H/lpr mice showed reaction product in the vessels of the cochlea, particularly the stria vascularis and bony capsule. Less frequent sites of staining were the geniculate ganglion, marrow cavities of the bony capsule, tensor tympani muscle, and on one occasion, a hair cell of the organ of Corti. These findings indicate that IgG is widespread within the cochlea and its vessels during systemic autoimmune disease and not directed against any specific sensorineural structure. This suggests a generalized or indirect mechanism whereby such systemic disease affects the inner ear.
Animals↗
The spinal cord injury primary physician. One riot--one ranger.
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Comprehensive Health Care↗
Initial experience with laparoscopic surgery: establishing a new surgical procedure.
Laparoscopic surgery impacted the surgical world in the United States in 1990. This report reviews the initial experience of 34 surgeons in 8 teaching hospitals of the Northeastern Ohio Universities College of Medicine. There were 538 cases reported from May 1, 1990 to January 31, 1991. There was no mortality and the morbidity rate was 4.8%, including three bile duct injuries. The conversion rate to an open procedure was 6.1%. The criteria for credentialing, training, and resident and faculty education are included. The data reported by the Surgery Department of Northeastern Ohio Universities College of Medicine are very similar to reported series from the current literature.
Adult↗
Acoustic neuroma: postoperative vertigo and the mechanisms of compensation.
Ninety-five percent of patients with acoustic neuroma experience some degree of vertigo preoperatively, postoperatively or both. Postoperative vertigo is often a debilitating condition that results when the eighth cranial nerve is severed during surgery to resect a tumor growing around the vestibular portion of this nerve. Thus, surgery for acoustic neuroma affects the membranous labyrinth, which is the functional part of the vestibular apparatus and is primarily concerned with equilibrium. Compensation for impaired equilibrium may be by biofeedback in the vestibular pathways, visual control, exercise or drug therapy. Nurses can significantly influence the recovery of acoustic neuroma patients by encouraging and reinforcing exercise and other mechanisms of vestibular compensation.
Adaptation, Physiological↗
Endothelial-dependent and -independent responses in the thoracic aorta during endotoxic shock.
Endotoxic shock is characterized by a variety of hemodynamic disturbances which result in tissue hypoperfusion. There is some evidence for endothelial damage caused by endotoxin. The present study addressed the hypothesis that vascular responsiveness to endothelial-dependent vasodilators is altered in endotoxic shock. Dose-response relationships for an endothelial-dependent vasodilator, acetylcholine, and an endothelial-independent vasodilator, adenosine, were determined in guinea pig aortic rings. Rings were examined from either control (untreated) animals or from animals given Escherichia coli endotoxin (4 mg/kg, i.p.) 16 hr prior to functional studies. Dose-response relationships to adenosine were similar in aortic rings from control and shocked animals. However, response to acetylcholine were attenuated by 30% (P less than .05) in the shocked group. To distinguish between a direct, acute effect of endotoxin versus effects produced by systemic changes that occur during shock, rings were isolated from untreated animals and incubated with endotoxin in vitro for 30 min prior to and during dose-response measurements. Incubation with endotoxin caused no change in aortic responses to adenosine or acetylcholine. Electron microscopy revealed a separation of the endothelium from the internal elastic lamina and an increase in inter-endothelial gaps in rings isolated from shocked animals. These structural changes were not observed in rings from untreated animals or in rings incubated with endotoxin in vitro. We conclude that endothelial-dependent vasodilation is attenuated during endotoxic shock. The functional changes are correlated with ultrastructural alterations of the endothelium.
Acetylcholine↗
Common duct stone push-through.
Most common duct stones are located below the junction of the cystic duct and the common bile duct. We describe a technique of trans-cystic-duct manipulation of stones through the ampulla of Vater and into the duodenum which we have termed common duct stone push-through (CDSPT). A balloon catheter is inflated above the stone and pushed into the duodenum several times. Successful manipulation of the stone into the duodenum is confirmed by repeat cholangiography. Stones were successfully manipulated by CDSPT in seven patients over a brief period starting June 1988.
Catheterization↗
Nutrient and nonnutrient renal blood flow.
The role of prostaglandins in the distribution of total renal blood flow (TRBF) between nutrient and nonnutrient compartments was investigated in anesthetized mongrel dogs. Renal blood flow distribution was assessed by the xenon 133 freeze-dissection technique and by rubidium 86 extraction after ibuprofen treatment. Ibuprofen (13 mg/kg) significantly decreased TRBF by 16.3% +/- 1.2% (mean +/- SEM electromagnetic flow probe; p less than 0.005), but did not alter blood flows to the outer cortex (3.7 vs 4.3 ml/min per gram), the inner cortex (2.6 vs 2.7 ml/min per gram), and the other medulla (1.5 vs 1.5 ml/min per gram), which suggests a decrease in nonnutrient flow. In a separate group of animals the effect of reduced blood flow on the nutrient and nonnutrient components was determined by mechanically reducing renal arterial blood flow by 48%. Unlike the ibuprofen group, nutrient blood flows were proportionally reduced with the mechanical decrease in TRBF in the outer cortex (1.9 ml/min per gram, p less than 0.05), the inner cortex (1.4 ml/min per gram, p less than 0.05), and the outer medulla (0.8 ml/min per gram, p less than 0.01). These results indicate no shift between nutrient and nonnutrient compartments. Nutrient and nonnutrient renal blood flows of the left kidney were also determined by 86Rb extraction. After ibuprofen treatment, nonextracted 86Rb decreased to 12.1% from the control value of 15.6% (p less than 0.05). Mechanical reduction of TRBF did not significantly decrease the proportion of unextracted 86Rb (18.7%).(ABSTRACT TRUNCATED AT 250 WORDS)
Animals↗
[Development of minocycline containing polycaprolactone film as a local drug delivery].
Local drug delivery by using biocompatible polymers has been developed in the treatment of periodontitis for many years. The purpose of this study was to examine the release kinetics of minocycline from monolithic film prepared from polycaprolactone and polyethylene glycol and to examine the antimicrobial activity in vitro. Polycaprolactone (Mwt 60,000), polyethylene glycol and minocyline was dissolved by chloroform, which was vigorously stirred for 24 hours and it was dried in vacuum chamber. The thickness of cast films containing 20%, 30% and 40% minocycline was 200 +/- 10 microns. Release rate of minocycline from the film was measured by means of a UV spectrophotometer. In vitro releasing test, each film showed a large burst effect within first two and three hours and a steady state release kinetic at the rate of 4-8 micrograms/cm/hour for 7 days. In antimicrobial test, each sample (one fourth inch in diameter) sunk in the broth that had been innoculated with periodontopathic bacteria showed growth inhibitory activity after 48 hr anaerobic incubation. In cytotoxicity test, there was no significant cytotoxic effect in casting film to human gingival fibroblast. This study showed that, by embedding minocycline in polycaprolactone, it is feasible to obtain substained release of the drug within the periodontal pocket for seven days and should be useful tool for elimination of pathogenic microflora from periodontal pocket or reducing inflammation in periodontal disease.
Adolescent↗
Hemodynamic and renal advantages of dual cyclooxygenase and leukotriene blockade during canine endotoxic shock.
The decline in mean arterial pressure (MAP), cardiac output (CQ), and renal blood flow (RBF) that accompany endotoxic shock is partly ameliorated by cyclooxygenase or leukotriene blockade. This study determined whether dual cyclooxygenase and leukotriene blockade provided greater hemodynamic protection than either single blockade alone. Mongrel dogs were pretreated with either ibuprofen or LY171883 alone or dual blockade consisting of ibuprofen combined with LY171883 or propylgallate, then given Escherichia coli endotoxin, and monitored for 10 hr. Postendotoxemic MAP was equally maintained with dual blockade and with ibuprofen. For the first 5 hr postendotoxin, CQ was best maintained by dual blockade. However, by 9 hr postendotoxin, CQ in LY171883-treated animals was 88 +/- 8% of control. LY171883 provided the greatest protection of RBF, while dual blockade provided the least protection for both RBF and urine flow rates (V). Ibuprofen-treated dogs required less NaHCO3 for acid-base maintenance than did dual-blocked animals. In summary, dual cyclooxygenase and leukotriene blockade was advantageous in protecting MAP and CQ during the early phases of shock but provided no greater protection of RBF, GFR, V or acid-base balance than did single blockade. Overall, LY171883 provided the best protection from circulatory dysfunction.
Acetophenones↗
Potentiation of noise induced threshold shifts and hair cell loss by carbon monoxide.
Previous studies have determined that severe systemic hypoxia disrupts cochlear function acutely, but have suggested that augmentation of cochlear perfusion may successfully protect cochlear function under all but the most profound hypoxic treatments. In the current study we report on the chronic effects of simultaneous exposures to noise and carbon monoxide on pure tone thresholds and hair cell survival in rats. Following initial threshold determination, rats received acute exposure to carbon monoxide, noise, or both agents concurrently. Thresholds were evaluated 2-4 and 6-8 weeks later. The data show that carbon monoxide alone does not affect either auditory thresholds or compromise hair cells at the light microscopic level. The noise exposure alone produced variable, but quite limited permanent threshold shifts which were related to the power spectrum of the broad band noise that was employed. Hair cell loss was restricted to the basal turn of the cochlea. Simultaneous exposure to carbon monoxide and noise induced large threshold shifts at all frequencies studied, but the effect was greatest at the highest test frequency; an effect not consistent with the noise power spectrum. Widespread hair cell loss persisted over fully half of the basilar membrane in the most severely affected rat. Outer hair cells appear to be particularly vulnerable. Carbon monoxide plus noise did not appear to preferentially disrupt a particular row of outer hair cells. These data complement existing evidence that hyperoxia can mitigate against noise induced injury and reinforce the view that some types of noise induced damage may result from metabolic insufficiencies.
Acoustic Stimulation↗
Immunological relatedness of annelid extracellular hemoglobins and chlorocruorins.
1. The immunological relatedness of several annelid extracellular hemoglobins and chlorocruorins was investigated using ELISAs and Western blotting to determine the binding of purine polyclonal and monoclonal antibodies to Lumbricus terrestris hemoglobin with the hemoglobins of Tubifex tubifex, Tylorrhynchus heterochaetus, Arenicola marina and Macrobdella decora and the chlorocruoins of Myxicola infundibulum and Eudistylia vancouverii. 2. Polyclonal antibodies to Lumbricus terrestris hemoglobin bound to all the other hemoglobins and chlorocruorins. However, the titers were in all cases one to several orders of magnitude smaller than with Lumbricus terrestris hemoglobin. 3. Polyclonal antibodies to Eudistylia vancouverii chlorocruorin bound to the hemoglobins of Lumbricus terrestris, Tubifex tubifex, Arenicola marina, Tylorrhynchus heterochaetus and Macrobdella decora. 4. Of the nine monoclonal antibodies to Lumbricus terrestris hemoglobin isolated, two (No. 24 and No. 26) bound to the other hemoglobins and to Myxicola chlorocruorin, but the binding was again weaker than with Lumbricus hemoglobin. Antibody No. 26 also bound to Eudistylia chlorocruorin. Although antibody No. 24 appears to recognize a conformation-dependent epitope, antibody No. 26 recognizes a common epitope in each of the four subunits M, D1, D2, and T of unreduced Lumbricus hemoglobin. 4. An additional two monoclonal antibodies to Lumbricus hemoglobin (No. 21 and No. 25) bound also only to Tubifex hemoglobin. Antibody No. 21 recognizes subunits D1 and M of Lumbricus hemoglobin and No. 25 appears to recognize a conformation-dependent epitope.
Animals↗
Sensory threshold estimation from a continuously graded response produced by reflex modification audiometry.
This article describes the use of reflex modification to determine sensory detection thresholds. The method is based upon the finding that low-intensity sensory stimuli presented shortly before a reflex eliciting stimulus are able to modify the amplitude of the reflex. The extent of such modification is related to the intensity of the initial low-intensity stimulus. In contrast to earlier reported procedures for threshold estimation, the method described in this article consists of fitting a smooth function to the relationship between startle response amplitude and the intensity of the inhibiting stimulus. The method entails fitting a cubic spline function to the medians of the square-root reflex amplitude at each prestimulus intensity. The resulting audiometric curves closely approximate audiometric data obtained from traditional operant methods both in sensitivity and shape. Parametric data are also presented that allow for optimizing stimulus presentation so as to obtain reliable thresholds using a minimal number of test trials. The procedures developed in this article may prove useful in other situations involving the estimation of a threshold effect from a continuously graded response.
Animals↗
Carbon monoxide exposure potentiates high-frequency auditory threshold shifts induced by noise.
Hypoxia has long been hypothesized to play a role in noise-induced hearing loss, and the disruption of auditory function by asphyxiation has been repeatedly demonstrated. Recent data, however, suggest that the cochlea is resistant to less extreme hypoxic events. The current report describes the combined effects of noise and hypoxia on a measure of auditory function, in an effort to clarify the role of hypoxia in hearing loss. Exposure to 1200 parts per million of carbon monoxide in air for 90 min preceding and 120 min concurrent with exposure to a broad-band noise at 110 dBA produced high-frequency threshold shifts of greater magnitude than those produced by exposure to noise alone. An equivalent carbon monoxide exposure in a 'quiet' environment did not produce any change in auditory detection thresholds. The potentiation of noise-induced threshold shifts by carbon monoxide provides additional support for the hypothesized role of metabolic exhaustion or bloodflow impairment in noise-induced hearing loss. It also suggests a possible interpretation of clinical findings of auditory impairment associated with carbon monoxide exposure.
Animals↗
Trimethyltin exposure produces an unusual form of toxic auditory damage in rats.
A single injection of trimethyltin chloride (TMT; 2, 4, or 6 mg/kg) is shown to produce a frequency-specific, dose-dependent auditory impairment, as well as to decrease the amplitude of the acoustically elicited startle response, in exposed rats. This finding stands in contrast to data presented earlier on the effects of triethyltin bromide (TET), which produces changes in startle response without affecting auditory acuity. Animals intoxicated with TMT at moderate doses appear to recover their auditory acuity over the course of several weeks. This slow recovery of auditory function, which is uncharacteristic for chemical ototoxicity, suggests that TMT may be a useful model agent for studying ototoxic mechanisms.
Acoustic Stimulation↗
Trimethyltin ototoxicity: evidence for a cochlear site of injury.
The environmental contaminant, trimethyltin (TMT), produces a profound elevation in tone intensity necessary to inhibit the acoustic startle reflex in laboratory animals which recovers over a prolonged period except at very high frequencies. The recovery that is observed does not begin until 3 to 5 weeks after a single acute administration depending upon dosage. As opposed to the very temporary threshold shifts by the salicylates and loop diuretics or the permanent and progressive ototoxicity resulting from aminoglycoside antibiotics the time course for recovery of acoustic startle reflex inhibition after TMT appears to be an anomaly for a chemical ototoxicant. In terms of the duration of loss only, this pattern appears similar to that sometimes observed after noise exposure. The current investigation replicates the finding that recovery of acoustic startle reflex inhibition after TMT is frequency related in that only the highest frequency impairment appears to be permanent. While this frequency dependence suggests a cochlear locus of injury, both the known neurotoxic effects of TMT and the time course of the behavioral impairment suggest a more central locus of injury. Compound action potential and cochlear microphonic recordings made from the round window in the current study confirm a preferential high frequency effect of TMT and demonstrate a significant cochlear component to the ototoxic effects of this agent.
Action Potentials↗
Effects of copper on the sabellid polychaete, Eudistylia vancouveri: I. Concentration limits for copper accumulation.
Three experiments with a sabellid polychaete (Eudistylia vancouveri) show the threshold concentration for increasing copper accumulation with time to lie between 3 and 6 micrograms/L total copper in seawater during winter conditions. The branchial crown, probably the major absorptive site, concentrated more copper than the body. Accumulation was influenced by size but not by sex. Our studies indicate that the body burden of copper will increase above natural levels in areas of industrial discharge where copper levels are above the threshold limit for accumulation.
Animals↗
On the occasion of Sir Ludwig's 80th birthday.
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Anniversaries and Special Events↗