Rapid cardiology--for chest pain, breathlessness and palpitations.
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Angina Pectoris↗
Biomedical subjects
S R Gibbs
Publications and source records attributed to S R Gibbs.
Respiratory difficulty following bismuth subgallate aspiration.
Bismuth subgallate, an agent that initiates clotting via activation of factor XII, has been advocated for use in controlling bleeding during tonsillectomy and adenoidectomy. Direct aspiration of bismuth has produced pulmonary complications in laboratory animals, but no clinical correlation in humans has been previously described. We report 2 cases of bismuth aspiration that resulted in respiratory difficulty after tonsillectomy and adenoidectomy. Neither child's respiratory compromise required airway intubation. This report of pulmonary complications secondary to bismuth aspiration should alert surgeons to the potential for airway problems when using bismuth as a hemostatic agent for tonsillectomy and adenoidectomy.
Adenoidectomy↗
Botulinum toxin for the treatment of spasmodic dysphonia.
Spasmodic dysphonia is a focal laryngeal dystonia. Laryngeal dystonia presents as: adductor spasmodic dysphonia with the characteristic strain-strangle voice; abductor spasmodic dysphonia with hypophonia and breathy breaks in connected speech; and adductor respiratory dystonia with paradoxical vocal fold motion and intermittent stridor. Current treatment with periodic laryngeal intramuscular injections of botulinum toxin A has allowed patients to function more normally. In this article, the authors' treatment paradigm and experience in treating over 900 patients with laryngeal dystonia are discussed.
Anti-Dyskinesia Agents↗
Electrocochleographic changes after intranasal allergen challenge: A possible diagnostic tool in patients with Meniere's disease.
Numerous observers have suggested a relationship between allergy and Meniere's disease, but objective proof has heretofore been limited. Using standard criteria, we studied a group of 7 patients with previously diagnosed Meniere's disease in whom significant allergy to 1 or more inhalants had also been diagnosed. Patients underwent a baseline electrocochleographic study followed by intranasal challenge with a carefully quantified amount of the allergen to which they were most sensitive. This was followed by a second electrocochleogram. Four of the 7 patients demonstrated at least a 15% increase in the summating potential/action potential ratio in 1 ear, associated with the production of subjective inner ear symptoms. We present this protocol as a potentially useful tool to further study whether inhalant allergy may be a causative factor in patients with Meniere's disease.
Administration, Intranasal↗
Characterization of the collagen phenotype of rabbit proximal tubule cells in culture.
Studies were performed to characterize the collagen phenotype of cultured rabbit proximal tubule (RPT) epithelial cells grown on plastic and on the reconstituted basement membrane preparation, Matrigel. When grown on a plastic substratum, RPT cells display a cobblestone appearance characteristic of glomerular epithelial cells. While initially forming an interlocking network of cells after subculture on Matrigel, this pattern of culture morphology rapidly develops into one characterized by isolated, organized groups of cells. Notwithstanding the effects of Matrigel on culture morphology, total cellular proliferation was reduced only 25% when RPT cells were grown on this substrate. Greater than 90% of the collagen synthesized by RPT cells grown on plastic was secreted into the culture medium. Qualitative analysis by SDS-PAGE revealed components exhibiting electrophoretic mobilities corresponding to the chains present in type IV and type I collagens. Quantitative analysis by CM-Trisacryl chromatography established that approximately 2/3 of the total collagen synthesized by RPT cells grown on plastic was type IV and approximately 1/3 type I. Quantitative analysis of the collagens produced by RPT cells grown on Matrigel again indicated the synthesis of only type IV and type I molecules but in a slightly more equal ratio of both collagen types and in the ratio of secreted to cell-associated molecules. However, the total amount of collagen synthesized by RPT cells grown on Matrigel was reduced to approximately 1% of the level synthesized by the cells grown on plastic. On plastic, approximately 3/4 of the type I collagen produced was recovered as the type I homotrimer, but on Matrigel type I homotrimers represented only approximately 55% of the total type I collagen synthesized. On Matrigel, the majority of the type IV collagen was recovered as heterotrimers containing alpha1(IV) and alpha2(IV) chains. In contrast, RTP cells grown on plastic predominantly produced type IV homotrimers containing only the alpha1(IV) chain. These data represent the initial report describing the collagens produced by nonimmortalized cultured proximal tubule cells. The finding that a significant amount of the total collagen synthesized was type IV (basement membrane) collagen, regardless of culture substrate, suggests that the RPT cells have maintained a significant degree of differentiation in culture, and thus establishes RPT cells as an appropriate model for investigating ECM changes in proximal tubule cells that occur in kidney disease. Finally, the observation that culture of RPT cells on a reconstituted basement membrane preparation results in a significant reduction in total collagen production and alterations in the molecular forms of type IV and type I molecules synthesized indicates that integrity of the tubular basement membrane may represent an important component in preventing the development of tubulointerstitial fibrosis.
Animals↗
Balloon device for experimental graded spinal cord compression in the rat.
We have developed a balloon device that creates reproducible graded compression of the rat spinal cord. It uses a modified Camino intracranial pressure monitor bolt with a small latex balloon attached to the tip. The device is affixed to the spinous processes of two cervicothoracic vertebrae and positioned directly over an exposed segment of spinal cord. Ten compression balloons were tested and revealed reproducible pressure transmission at expansion volumes from 0.12 to 0.34 cc. Reversible graded spinal cord compression was verified by monitoring cortical somatosensory and motor evoked potentials before, during, and after cord compression. The pathophysiologic changes occurring with graded compression and the effect of therapeutic interventions can be studied in a rat model.
Animals↗
Endoscopic treatment of carpal tunnel syndrome: a critical review.
OBJECT: The goal of this paper is to present a critical review of the endoscopic procedures currently in use for the treatment of carpal tunnel syndrome. Endoscopic techniques and outcomes are discussed. METHODS: An extensive review of published articles on the subject of endoscopic carpal tunnel release surgery is presented, encompassing six endoscopic techniques used to treat carpal tunnel syndrome. Since the first report in 1987, 7091 patients have undergone 8068 operations. The overall success rate has been 96.52%, with a complication rate of 2.67% and a failure rate of 2.61%. The mean time to return to work in patients not receiving Workers' Compensation was 17.8 days, ranging between 10.8 and 22.3 days. The most common complications were transient paresthesias of the ulnar and median nerves. Other complications included superficial palmar arch injuries, reflex sympathetic dystrophy, flexor tendon lacerations, and incomplete transverse carpal ligament division. In many studies in which open and endoscopic techniques were compared, it was reported that patients in the the latter group experienced significantly less pain and returned to work and activities of daily living earlier. CONCLUSIONS: Success and complication rates of endoscopic carpal tunnel release surgery are similar to those for standard open procedures.
Absenteeism↗
Endoscopic treatment of carpal tunnel syndrome: a critical review.
An extensive review of published articles on the subject of endoscopic carpal tunnel release surgery is presented, encompassing six endoscopic techniques used to treat carpal tunnel syndrome. Since the first report in 1987, 7091 patients have undergone 8068 operations. The overall success rate has been 96.52%, with a complication rate of 2.67% and a failure rate of 2.61%. The mean time to return to work in patients not receiving Workers' Compensation was 17.8 days, ranging between 10.8 and 22.3 days. The most common complications were transient paresthesias of the ulnar and median nerves. Other complications included superficial palmar arch injuries, reflex sympathetic dystrophy, flexor tendon lacerations, and incomplete transverse carpal ligament division. All studies in which open and endoscopic techniques were compared reported that patients in the latter group experienced significantly less pain and returned to work and activities of daily living earlier. The reported success and complication rates of endoscopic carpal tunnel release surgery are similar to those for standard open procedures. Endoscopic techniques and outcomes are discussed.
Journal Article↗
Carotid-cavernous sinus fistulae in craniofacial trauma: classification and treatment.
Carotid-cavernous sinus fistulae (CCF) represent pathological communications between the intracavernous internal carotid artery and the cavernous venous sinus. Although trauma is the most common cause of high flow carotid cavernous fistulae, they are relatively uncommon in patients sustaining craniofacial trauma. Nevertheless, CCF require early diagnosis and rapid and effective treatment in order to prevent severe and significant morbidity. Clinical presentation may include pulsatile proptosis, ocular and orbital erythema, chemosis, diplopia, headaches, and visual loss. Cerebral angiography is currently the definitive diagnostic study. Obliteration of the fistula by endovascular techniques is the current mainstay treatment, and direct surgery is reserved for cases that have failed endovascular therapy. This article reviews clinical features, pertinent anatomy, and therapeutic approaches to carotid-cavernous sinus fistulae.
Arteriovenous Fistula↗
Motor-evoked potential changes during hypoxic hypoxia.
Motor-evoked potentials (MEPs) from forearm muscles were recorded in response to single-shock electrical stimulation of motor cortex of rats (n = 15) under pentobarbital anesthesia and controlled room air ventilation. In addition, electroencephalograms (EEGs) were recorded for all animals. Following baseline MEP recording in room air (21% O2), animals were subjected to graded hypoxia of either 15.75%, 10.5%, or 5.25% oxygen for 10 minutes, then followed by room air ventilation for 15 minutes. The mean baseline latency, amplitude, and duration of the evoked muscle response were 4.3 +/- 0.4 mseconds, 556 +/- 476 microV, and 9.6 +/- 2.3 mseconds, respectively. At moderate hypoxia (15.75%), the latency was 4.2 +/- 0.5 mseconds and the amplitude and the duration were 530 +/- 356 microV (n = 14), and 9.5 +/- 2.2 mseconds, (n = 14). These values did not deviate significantly from baseline (p > 0.56). Only one animal lost MEPs at the 15.75% hypoxia level. At 10.5% hypoxia, 27% of animals (n = 4) lost MEP within minutes. In the remaining animals (n = 11), there was a trend toward a prolongation of latency and a decrease of both amplitude and duration. All animals lost MEPs under extreme hypoxia (5.25%) within 2 minutes. No change was seen in the EEG recording until the level of extreme hypoxia was reached. The loss of MEPs at this level of hypoxia was concurrent with the loss of EEGs. We conclude that hypoxia effects MEPs in experimental animals.
Animals↗
Effect of graded hypoxia on cortical and spinal somatosensory evoked potentials.
Cortical somatosensory evoked potential (CSEP), spinal somatosensory evoked potential (SSEP), and electroencephalogram were recorded in rats under pentobarbital anesthesia. After baseline recordings in room air (21% O2), animals were subjected to a graded hypoxia at 15.75%, 10.5%, and 5.25% oxygen levels for 10 minutes. Each level of hypoxia was followed by a 15-minute reoxygenation period. With a moderate hypoxia (15.75% O2), measured latencies for the CSEP and the SSEP were not significantly different compared with baseline (p greater than 0.05). The CSEP amplitude showed a significant increase (p = 0.02) during reoxygenation after the moderate hypoxia. Change in the latency or amplitude of SSEP at 15.75% hypoxia or during the reoxygenation period was not significant compared with the room air (p greater than 0.05). No change in the electroencephalogram was noticed with the moderate hypoxia. At severe hypoxia (10.5% O2), 80% of the animals lost CSEP within 2 minutes. The loss of CSEP was concomitant with significant attenuation of the electroencephalogram waves. The SSEP was resistant to the severe hypoxia and was present in all animals. We concluded that hypoxia affects CSEP with the tendency to increase the amplitude at moderate hypoxia (15.75%) and loss of the latency and amplitude with severe (10.5%) and extreme (5.25%) hypoxia.
Animals↗
Plasma levels of glucose, ketone bodies, lactate, and alanine in the vascular supply to and from the brain of the adult American bullfrog (Rana catesbeiana).
Serial, paired blood samples were collected via cannulae chronically placed in the common carotid artery (A) to and the internal jugular vein (V) from the brain of the fasted adult American bullfrog (Rana catesbeiana). Plasma glucose, beta-hydroxybutyrate, acetoacetate, lactate, and alanine levels were measured by standard enzymatic procedures. Cannula failure ended sampling after 1-2 days in most animals. The common carotid artery plasma metabolite levels were greatest at the time of surgery and subsequently declined to relatively stable levels. The summarized data indicated glucose uptake and alanine release by the brain, but no significant beta-hydroxybutyrate or lactate A-V percentage changes. Initially, acetoacetate levels also were measured, but were discontinued in favor of continued beta-hydroxybutyrate determinations when no significant A-V percentage changes occurred. Separate analysis of the metabolite levels during the surgery and recovery period (less than or equal to 24 hr) and the "normal" under the experimental conditions period (greater than 24 hr) revealed that summarizing the data masked important A-V percentage changes during the two different physiological conditions. Glucose was the only metabolite extracted by the brain during the less than or equal to 24 hr period of elevated and subsequently declining metabolite levels. In contrast, glucose uptake did not occur during the greater than 24 hr period of stable levels, but there was lactate release. If the bullfrog brain stores substantial glycogen as do the other ectothermic vertebrates studied, glucose uptake when plasma levels are elevated, for example after feeding, may serve both to fuel the brain and to replenish endogenous glycogen reserves that may be mobilized to provide glucose for the brain after plasma glucose levels return to normal. Assuming that mammalian and bullfrog metabolic pathways are the same, the release of lactate and alanine by the brain, possibly to remove excess pyruvate and to regenerate NAD+, is consistent with this hypothesis. It remains to be determined for how long endogenous energy sources alone can support the bullfrog brain, and if plasma glucose, ketones, and/or other energy sources are extracted as endogenous brain fuels become exhausted.
Alanine↗
Ventricular septal defects in a family of Yucatan miniature pigs.
We have studied the hearts from a colony of Yucatan miniature pigs with spontaneously occurring congenital defects. Ventricular septal defect was encountered in 57 of 81 neonates from 15 consecutive litters. Of 73 hearts preserved for morphological assessment, 52 were found to have defects within the ventricular septum remarkably similar to those observed in humans with deficient ventricular septum. The defects, including 3 which had closed spontaneously, were perimembranous in 34, muscular in 12 and doubly committed and juxtaarterial in 6 hearts. Atrial septal defects were found in 12 of the 52 hearts with deficient ventricular septation; only 1 atrial septal defect was seen among 21 hearts with an intact ventricular septum. Anomalies of the aortic arch were associated with ventricular septal defect in 2 cases; 1 with a solitary arterial trunk and one with hypoplasia of the aorta and patent arterial duct. All these findings are replicated in human hearts. This strain of pig provides an ideal large animal model for morphologic and genetic investigations concerning the details of ventricular septation, including potential mechanisms of late spontaneous closure.
Animals↗
A simple disposable continuous-infusion swivel for unrestrained small animals.
An easy-to-prepare inexpensive disposable infusion swivel for small animals is described for acute and chronic experiments. The swivel is constructed from common plastic laboratory syringe components, needles, and a three-way stopcock.
Animals↗
Characterization of beta-adrenergic receptors in fresh and primary cultured bovine corneal endothelium.
Homogenates of fresh bovine corneal endothelium and of cells from primary cultures exhibited high affinity binding of [3H]-dihydroalprenolol, a specific beta-adrenergic antagonist. The binding was rapid and reversible. Specific binding of the radioligand in each preparation was saturable with half-maximal binding occurring at 0.5 nM. Homogenates of fresh tissue consistently showed a higher maximal binding capacity than did those from cell cultures. Both homogenates bound adrenergic agents in a manner consistent with the labelling of beta-adrenergic receptors. The relative affinities of epinephrine and norepinephrine indicated that beta-adrenergic receptors in both preparations are of the beta 2 subtype. The beta-adrenergic agonist, isoproterenol, increased the cAMP content of intact, cultured endothelial cells 27-fold over control. This effect was completely blocked by the beta-adrenergic antagonist, propranolol. Bovine corneal endothelial cells in primary culture contain beta-adrenergic receptors which are essentially identical to those from in vivo sources and appear to be linked functionally to cAMP synthesis in these cells.
Animals↗
Characteristics of beta-adrenergic receptors in bovine corneal epithelium: comparison of fresh tissue and cultured cells.
The characteristics of the beta-adrenergic receptors in homogenates of fresh tissue and cultured bovine corneal epithelium were compared using [3H]dihydroalprenolol. High affinity, specific binding sites were observed in both preparations. Fresh tissue exhibited a higher binding site density (165 fmol/mg protein) than did cells in culture (57 fmol/mg protein). Studies with various beta-adrenergic agonists and antagonists indicated that binding characteristics were typical of beta-adrenergic receptors, predominantly of the beta 2 subtype. These results demonstrate that beta-adrenergic receptors exist in both fresh and cultured bovine corneal epithelium and that these receptors are qualitatively and quantitatively similar.
Animals↗
Allergic fungal sinusitis-induced visual loss.
In this report we review 56 adult and 26 pediatric patients who presented to our practice with pathologically confirmed allergic fungal sinusitis from 1989 to 1997. Of this group, three patients presented with visual loss and were treated with prompt surgical decompression followed by immunomodulation.
Adolescent↗