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Biomedical subjects

J P Caron

Publications and source records attributed to J P Caron.

At least 19 recordsLinked to original sources
PubMed1993

Substance P innervation of equine synovial membranes: joint differences and neural and nonneural receptor localizations.

Substance P (SP) immunocytochemistry and receptor autoradiography were used to define the innervation of the equine synovial membrane of joints equivalent to the wrist and knuckle of man. SP-immunoreactive fibers were mainly concentrated around blood vessels in the subsynovial layer, although not exclusively, while in the more distal joint, SP fibers were more frequently seen in the synovial surface layer. Iodinated SP receptor autoradiography studies revealed silver grain concentrations in the advential layer of blood vessels associated with the vasa vasorum, on the vascular endothelium and in the synovial surface. These findings suggest that SP has various sites of action within the synovial membrane, each of which may contribute both a sensory function and a different component of the inflammatory process to the joint.

Animals↗
PubMed1993

Neuropeptidergic innervation of equine synovial joints.

Immunocytochemical analysis of equine synovial membranes revealed presence of several neuropeptides, including substance P (SP), neurokinin A, and neuropeptide Y, in nerves of the radiocarpal, middle carpal, and metacarpophalangeal (fetlock) joints. Within the subsynovium, these neuropeptides were located perivascularly, whereas in the fronds, only neuropeptide Y was restricted to the vessels of the synovial membrane. Only SP and neurokinin A were found in the intimal layer. The intimal layer of the metacarpophalangeal joint contained more SP-immunoreactive fibers than were observed in the intimal layer of the radiocarpal joint. Substance P also was detected in the synovial fluid from all 3 joints, but mean +/- SD concentrations were significantly different only between the middle carpal joint (37.56 +/- 5.48 fmol/ml; n = 6) and the metacarpophalangeal joint (55.80 +/- 8.33 fmol/ml; n = 5) and between the middle carpal joint and the radiocarpal joint (52.43 +/- 14.60 fmol/ml; n = 7).

Animals↗
PubMed1992

Obstructive enterolith in an 11-month-old miniature horse.

An obstructive enterolith was diagnosed in an 11-month-old 68-kg miniature horse with a 24-hour history of mild, intermittent colic. Abdominal radiography revealed gas distention of the cecum and the right and left ascending colon, and a radiodense elliptical structure in the area of the left kidney. During exploratory laparotomy, the right dorsal colon was noticed to contain ecchymotic hemorrhage and generalized discoloration in the portion proximal to the location of the enterolith. While exteriorizing the ascending colon, it ruptured caudal to the diaphragmatic flexure in the right dorsal colon. Radiography of the enterolith did not reveal a metallic center, but division of the stone allowed identification of a canvas cloth, and chemical analysis determined the stone's composition to be ammonium magnesium phosphate. Although equine enteroliths were reported over 100 years ago and the factors involved in their formation were investigated, the reasons for their development have yet to be determined. The mean reported age of horses requiring abdominal surgery because of an obstructive enterolith is 10 years, with the youngest being 4 years. The time required for an enterolith to enlarge is unknown, although a true enterolith has not been reported in horses younger than 4 years of age.

Animals↗
PubMed1992

Substance P in the synovial membrane and fluid of the equine middle carpal joint.

This preliminary study was designed to determine whether the neurotransmitter substance P was present in the middle carpal synovial membrane of the normal horse and whether the neuropeptide could be identified in the synovial fluid of normal horses and those with joint diseases. Immunocytochemistry on middle carpal synovial membrane biopsies from fresh cadavers was used to demonstrate substance P-containing neural elements. Substance P was most abundant in the subintimal portion of the membrane, with occasional filaments coursing via synovial fronds to the intimal portion. Radioimmunoassay techniques were used on acidified acetonitrile-preserved synovial fluid samples to measure substance P concentrations. Fluid from 9 joints of 5 normal horses and 6 joints of 4 horses with joint diseases were analysed. Disease conditions included acute and chronic osteoarthritis and osteochondrosis. Synovia from normal horses contained a mean concentration of substance P significantly less than that of horses with joint diseases (P less than 0.05). Elevated concentrations of neurotransmitters in diseased joints suggests a potential contribution to the pathophysiology of joint disorders in horses.

Animals↗
PubMed1991

Influence of polysulfated glycosaminoglycan on equine articular cartilage in explant culture.

Articular cartilage explants from 3 horses were maintained in tissue culture to test the effects of a polysulfated glycosaminoglycan on proteoglycan biosynthesis. Cultures were exposed to concentrations of 0, 50, or 200 micrograms of the drug/ml for either 2 days or 6 days, and labeled with 35S, before measuring the content of sulfated proteoglycan in the culture media and in extracts of cartilage. In a second experiment, the explants were incubated with the isotope and subsequently exposed to the same concentrations of the polysulfated glycosaminoglycan for 4 days. Subsequently, the amount of remaining labeled proteoglycan was determined. Gel filtration chromatography was used to compare the hydrodynamic size of proteoglycans from the cartilage explants in each experiment. Polysulfated glycosaminoglycan caused a dose-dependent depression of sulfated proteoglycan synthesis, which was statistically significant after 6 days of exposure. Radioactive proteoglycan content in explants was similar in the experiment involving isotopic labeling prior to exposure to the drug. Proteoglycan monomer size was similar in all treatment groups. It was concluded that polysulfated glycosaminoglycan caused a modest depression in proteoglycan synthesis, had little effect on endogenous proteoglycan degradation, and did not influence the size of sulfated proteoglycans synthesized by normal equine chondrocytes in explant culture.

Animals↗
PubMed1990

Clinical use of epidural xylazine in the horse.

Xylazine was administered into the epidural space of nine horses to facilitate various perineal manipulations (ie rectovaginal laceration repair, replacement of prolapsed rectum and urethral extension). The resulting caudal analgesia was sufficient for all procedures. The duration of analgesia from a single injection of epidural xylazine (0.17 to 0.22 mg/kg bodyweight) was at least 3.5 h. No horses were ataxic during or after the treatment. This trial demonstrates that xylazine given into the epidural space of horses provides prolonged regional analgesia which is sufficient for clinical use.

Analgesia, Epidural↗
PubMed1989

Staphylectomy for treatment of dorsal displacement of the soft palate in two foals.

Dorsal displacement of the soft palate associated with dysphagia and aspiration pneumonia was diagnosed in 2 young foals. The displacement appeared to be congenital. Clinical signs associated with the condition were resolved after staphylectomy. Dorsal displacement of the soft palate is usually recognized in adult animals as an upper respiratory tract disease, but may be a contributing factor to dysphagia and lower respiratory tract disease in young animals.

Animals↗
PubMed1989

Silicone ocular prosthesis in horses: 11 cases (1983-1987).

Horses experience a number of ophthalmic diseases and injuries that may result in loss of function of the eye. In the treatment of end-stage ophthalmic disease or injury that precludes salvage of the eye, the use of an inert, silicone prosthetic implant is a cosmetic alternative to simple enucleation. Eleven horses treated either by enucleation and insertion of an intraorbital prosthesis (n = 9) or by evisceration and insertion of an intraocular prosthesis (n = 2) were evaluated for postoperative complications and for long-term cosmetic results. Of the 11 horses treated, complication rate was low; during hospitalization, 1 horse with an intraorbital implant developed a localized incisional infection that resolved in response to antimicrobial therapy. Nine horses were available for follow-up evaluation. Cosmetic appearance was rated as excellent in 5 horses and good in 4 horses. Insertion of an intraocular implant had the best cosmetic result. Complications were not reported by any owner or caretaker. Routine use of intraorbital and intraocular implants is encouraged because of their modest cost and ease of insertion.

Animals↗
PubMed1989

Caudal epidural analgesia in cattle using xylazine.

Each of 25 mature Holstein cows were given a single 5 mL epidural injection of one of four different concentrations of xylazine or saline. The onset, magnitude and duration of caudal epidural analgesia was quantitated with the use of a low voltage DC current applied to the perineal area. The dose that produced the longest duration of analgesia and produced the least ataxia or sedation was approximately 0.05 mg/kg (25 mg in 5 mL diluent). The analgesia produced by this xylazine dose was compared to a standard dose of epidural lidocaine (100 mg/5 mL) by the same method. To investigate the role of systemic absorption in the production of epidural analgesia, the previously utilized epidural xylazine dosage was given intramuscularly to four adult cows. Analgesia was quantitated as before and the results compared with epidural xylazine. Epidural xylazine produced a significantly greater duration of analgesia, as measured by this model, than did epidural lidocaine. Xylazine, given epidurally, produced greater perineal analgesia than did xylazine given intramuscularly.

Analgesia, Epidural↗
PubMed1988

Epidural injection of xylazine for perineal analgesia in horses.

Local anesthetics given in the epidural space of a horse may cause hind limb weakness in addition to analgesia. Because alpha 2 agonists given by epidural injection cause sensory blockade without motor effects in human beings and other species, their use in veterinary anesthesia is appealing. This study was designed to examine the effectiveness of xylazine HCl, an alpha 2 agonist commonly used in horses. Xylazine, 0.9% NaCl, and lidocaine were given by epidural injection to horses subjected to perineal electrical stimulation. Administration of xylazine (0.17 mg/kg of body weight, diluted to a 10-ml volume, using 0.9% NaCl) induced approximately 2.5 hours of local analgesia without apparent side effects. Higher doses of xylazine caused mild hind limb ataxia. Administration of lidocaine induced a similar duration of analgesia, with severe hind limb ataxia (100% incidence). We concluded that xylazine given by epidural injection results in safe, effective perineal analgesia in horses.

Analgesia, Epidural↗
PubMed1988

Cortical perfusion assessment with 123I-isopropyl amphetamine (123I-IAMP) in normal pressure hydrocepha lus (NPH).

NPH can be reversible after cerebrospinal fluid (CSF) diversion. In the past no reliable criteria could be defined to predict the successful outcome of CSF shunting. Several authors demonstrated an increased cerebral blood flow after lumbar puncture in patients with NPH, indicating an underlying impairment of cerebral circulation autoregulation. 123I-AMP brain tomoscintigraphy was applied to 23 individuals with NPH before and after CSF drainage. Of these 23 patients, 10 underwent surgical shunting. The frontal and parietal hypoactive cortical pattern was present in NPH but not pathognomonic. Under stimulation of CSF pressure lowering, seven patients with improved outcome after shunting demonstrated an increase of cerebral perfusion in these areas, whereas a decrease of activity was found in three patients whose clinical status was unchanged after CSF diversion. This tomoscintigraphic test may be an interesting additional criterion for surgical admission.

Adult↗
PubMed1988

Intracranial meningiomas in the elderly (over 70 years old). A retrospective study of 30 surgical cases.

The decision to operate on a patient older than 70 years for an intracranial meningioma is always difficult. Therefore a series of meningiomas treated surgically in 30 cases older than 70 years has been reconsidered and studied according to the following parameters: Karnofsky's rating scale, physiological status of the patient (A.S.A. criteria), perifocal oedema and mass effect. The locations of the meningiomas were: convexity 13, parasagittal 6, falx 2, pterion (sphenoid ridge) 5, orbito-cranial 3, jugum sphenoidale 1, tentorium (occipital) 1. Postoperative survival at day 30 shows a mortality rate of 23% which increases to 37% at day 90 including causes like decubitus ulcers and 3 cases of fatal pulmonary embolism. In a comparable series of 31 cases from 60 to 70 years, mortality rate was only 16% at day 90. Two parameters seem essential for quantifying surgical risk: clinical status, oedema and mass effect, evaluated by CT scan. The best conditions seem combined when Karnofsky rating scale is higher than or equal to 50 with no or only limited perifocal hypodensity and without mass effect. Although meningiomas may remain dormant for many years or can be kept under control medically for some time, their development is unpredictable. We think therefore that a reasonable surgical risk can be taken on patients with good physical status and favourable parameters at the time of diagnosis, particularly if the meningioma is located at the convexity where the risk of recurrence is minimal. On the other hand, patients with unfavourable parameters are not recommended for surgery.

Aged↗
PubMed1987

Balloon-tipped catheter arterial occlusion for prevention of hemorrhage caused by guttural pouch mycosis: 13 cases (1982-1985).

Epistaxis, caused by guttural pouch mycosis, was treated by balloon-tipped catheter and ligature occlusion of the involved arteries in 13 horses. In 7 horses, more than one artery was catheterized. Serious postoperative hemorrhage was prevented in all horses. Long-term endoscopic follow-up examination was possible in 8 horses, and all had complete regression of the fungal lesion as early as 5 weeks after surgery. Six of the 8 horses did not receive medical treatment. Problems related to the use of the balloon-tipped catheter technique were rare. There were incisional infections in 3 horses, catheter breakage during removal occurred twice, and in one horse, a catheter was inappropriately placed.

Angioplasty, Balloon↗
PubMed1987

Vertebral hemangiomas presenting with neurologic symptoms.

Six cases of spinal hemangiomas with neurologic symptoms are reported. In three of them the diagnosis was obtained before surgery using plain x-rays and spinal computed tomography scan or biopsy. In the other cases the diagnosis was not done before surgery. In two cases preoperative embolization had minimized blood loss during surgery. Laminectomy was performed in three cases. Large removal and/or vertebrectomy was carried out in the other cases. Our results and a review of the literature about the investigations and treatment of vertebral hemangiomas led us to propose a stereotypical management of spinal hemangiomas with neurologic symptoms.

Adolescent↗
PubMed1987

Symptomatic xanthogranuloma of the choroid plexus of the third ventricle. A new case with ultrastructural study.

The clinicopathological findings in a new case of a surgically removed, symptomatic xanthogranuloma of the third ventricle are reported. Ultrastructural study showed that the lining epithelium of the tumor was composed of typical leptomeningeal cells, and that transitional forms from leptomeningeal cells into xanthomatous cells were present in the underlying fibrous capsule. These findings support the hypothesis of a leptomeningeal origin of the foamy cells in the present case. The ten cases reported previously of symptomatic xanthogranuloma of the third ventricle are reviewed. We suggest that xanthogranulomas of the choroid plexus might represent a heterogenous entity arising from xanthomatous changes involving various types of cells.

Brain Diseases↗
PubMed1987

[Occipital intraosseous epidermoid cyst producing a clinical picture simulating benign intracranial hypertension. A clinical case].

The authors describes a 17 years old woman with a small occipital intradiploic epidermoid cyst simulating a benign intracranial hypertension on an initial CT scanner. Digital angiography showed torcular compression by the tumor. Intracranial pressure and sagittal sinus pressure were analysed and implicated the epidermoid cyst as the cause of the intracranial hypertension.

Adolescent↗