Biomedical subjects
Publications and source records attributed to C Gibbs.
Partly obstructing, proliferative mucosal masses in the small intestine of two dogs were shown histologically to be hamartomatous polyps. They were characterized by an extension of smooth muscle from the muscularis mucosae into the lamina propria of the lesion. This is the first report of such lesions in domestic animals. In one of the dogs the lesion had become malignant.
Fifty dogs showing clinical signs of spinal disease were investigated by myelography, using iopamidol. In 27 cases the technique was considered worthwhile. Of the 19 dogs not subjected to surgery or euthanasia as a result of the findings, three suffered seizures during recovery from anaesthesia, eight deteriorated in neurological condition and one suffered permanent respiratory arrest as a result of extensive subarachnoid haemorrhage.
Nineteen cases of feline congenital urinary incontinence (10 cats with ureteral ectopia and nine with incompetence of the urethral sphincter mechanism) are reviewed. The 10 cats with ureteral ectopia are considered together with 13 from previous reports. There was no apparent breed predisposition. Most of the 23 cats were presented for urinary incontinence but two of them were continent. Thirteen were females and ectopia was unilateral in 13 and bilateral in 10. Twenty-eight of 31 ectopic ureters terminated in the urethra. The commonest complication was hydroureter/hydronephrosis (10 cases). Eighteen of the cats were treated surgically, 13 by ureteral transplantation, four by ureteronephrectomy and one by ligation of the renal blood vessels; 16 of them were cured by surgery. Congenital urethral sphincter mechanism incompetence has not been reported previously in the cat. Nine cases are presented and the urethras of all were markedly hypoplastic. A common concomitant abnormality was vaginal aplasia, with the uterine horns terminating in the dorsum of the bladder. Bacteriuria was more common in this group than in the cats with ureteral ectopia.
The immune response of Lewis rat lymph node T cells to guinea pig myelin basic protein (GP-BP) in experimental allergic encephalomyelitis is directed primarily against a region of basic protein encompassed by residues 72-89. T cells that respond to this epitope are restricted by the RT1.B class II molecule of the MHC and use V beta 8.2 exclusively in their TCR. A second region of GP-BP, residues 87-99, also induces experimental allergic encephalomyelitis in Lewis rats but this response is restricted primarily by RT1.D. Elsewhere we describe the biologic characteristics of T cell clones responding to the synthetic peptide, s87-99, and to a related peptide, s85-99. We present a detailed analysis of TCR V beta gene expression among these clones, derived from the lymph node and spinal cord of immunized animals, and among spinal cord derived T cell clones reactive to GP-BP 72-89. We find that spinal cord-derived clones, reactive to s85-99 and to s87-99, use V beta 6 predominantly. In contrast, T cell clones derived from lymph nodes and reactive to the same peptides express multiple V beta genes including V beta 6. This difference in heterogeneity of V beta usage at the clonal level is also seen in T cell lines derived from spinal cord and immune lymph node. DNA sequence comparison of the CDR3 regions in V beta 6+ spinal cord clones revealed a conserved amino acid motif also found in the majority of V beta 6 sequences from the spinal cord anti-s85-99 line. Although V beta 6 was expressed in some lymph node-derived clones, only one contained a CDR3 region similar to that seen in spinal cord isolates. All spinal cord-derived T cell clones reactive to GP-BP 72-89 used V beta 8.2 and most (five of six) contained the AspSer residues in CDR3 previously shown to be associated with V beta 8.2 receptors expressed by the majority of lymph node T cells responding to GP-BP 72-89. These data indicate that TCR V beta usage in peripheral T cells responding to an autoantigen does not always predict the V beta usage among T cells at the site of an autoimmune attack. Possible explantations for the relative homogeneity in TCR V beta expression seen in T cell clones derived from the spinal cord are discussed.
During a study of inflammatory middle ear disease in the dog cholesteatoma was found to accompany otitis media in seven of the 62 ears examined (11 per cent). The clinical, radiological and pathological findings in these animals imply that cholesteatoma in the dog is an aggressive lesion which must be differentiated from uncomplicated otitis media.
The electrophysiological features of progressive spastic paraparesis (PSP) associated with HTLV-1 in Chile, a non-tropical country, are presented. Twenty-two of 45 PSP subjects were positive for HTLV-1 antibodies. Trimodal evoked potentials were all normal in only 2 of these cases (9.1%). Somatosensory evoked potentials (SSEPs) were abnormal in 19 patients (86.3%) with a mean amplitude of 1.31 uV SD 0.92. Visual evoked potentials (VEPs) and brainstem auditory evoked potentials (BAEPs) were normal in all patients except four. Peripheral nerve conduction was normal in all but one who showed discrete slowness of the motor conduction velocity in the peroneal nerves. EMG was normal in 15 cases in whom it was performed. SSEP's were abnormal in 2 (8.7%) of 23 HTLV-1 negative cases with a mean amplitude of 2.4 uV SD 1.5, which is statistically different with respect to the positive cases (p less than 0.001). These results support an involvement of the spinal cord not restricted to the pyramidal tracts but also including subclinical damage of the posterior columns in PSP associated to HTLV-1.
Two-dimensional echocardiography (2DE) was performed on 22 unsedated Thoroughbred and part Thoroughbred horses weighing between 411 and 650 kg to establish normal reference values for 2DE measurements. Animals stood during examinations performed with a 3.5 MHz mechanical sector transducer using various transducer positions and tomographic planes. Right ventricular diameter (RVD), ventricular septal thickness (VSTh), aortic diameter (AoD), area of the chordal lumen of the left ventricle (CTA), left ventricular diameter (LVD) and left atrial diameter (LAD) were determined at ventricular end-diastole (Ed) and/or end-systole (Es). Fractional shortening (FS) of the left ventricle and end-systolic left atrial to aortic ratio (LAD-Es:AoD-Es) also were calculated. Echocardiographic data were related to body weight by linear regression analysis. Intra-observer variability was checked in five horses by measuring each parameter during each of 10 consecutive cardiac cycles. The 2DE data were compared with M-mode values in published reports. In the 18 horses whose weight did not exceed 551 kg, repeatable recordings of good quality were obtained, and 2DE measurements could be made using intra-cardiac reference points. Increasing body weight proved to impose substantial limitations on measurements taken with the available machine and transducer. This problem might be overcome by using probes of lower frequency or equipment with higher quality image display at greater depth. The following parameters correlated significantly to body weight: VSTh-Es (r = 0.69; P less than 0.01). AoD-Es (r = 0.64; P less than 0.01) and CTA-Es (r = 0.84; P less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)
Several studies report higher urinary GH excretion in acromegalic patients compared to control subjects. We investigated the diagnostic potential of overnight urinary GH excretion in acromegaly, using a recently developed enzyme-linked immunosorbent assay. Overnight urine samples were obtained from 117 control subjects and nine patients with untreated acromegaly. GH excretion was higher in acromegalic patients compared to control subjects, with geometric mean total overnight values of 46.35 and 5.73 microU respectively. The range for total overnight urinary GH in control subjects was 0.75-21.75 microU and two of the nine patients with untreated acromegaly had GH measurements within this range. Urinary GH measurements were corrected using predictive clinical variables but this resulted in minimal improvement in discrimination between control subjects and acromegalic patients. Lack of complete discrimination between control subjects and acromegalic patients limits the usefulness of a single overnight urinary GH measurement as a screening test for acromegaly.
This study was performed on 15 horses to validate the cardiac anatomy as imaged with two dimensional echocardiography (2DE) and to determine the accuracy of intracardiac measurements. 2DE images were recorded in five horses in life with a Diasonics DRF100 ultrasound system and a 3.5 MHz transducer in different tomographic planes. After slaughter, the hearts were fixed in 10 per cent formalin. To compare in vivo and in vitro results, the specimens were suspended in a water-filled tank and 2DE images were made using the same transducer positions as in life. In vitro 2DE and autopsy measurements of the same planes and parameters were also taken on a further 10 hearts, and the results were statistically compared. The in vivo 2DE images corresponded well with both in vitro 2DE recordings and anatomical sections. Repeatable imaging of each tomographic plane was possible on the post mortem hearts using intracardiac reference points. Comparison of parameters measured during in vitro 2DE and autopsy demonstrated a significant correlation between all 2DE and autopsy data (r: 0.879 to 0.926; P less than 0.001). Repeated 2DE measurements of each parameter showed a good reproducibility with coefficients of variation (CV%) varying between 4.6 to 10.6 per cent. The results suggest that 2DE is a reliable method for accurate anatomical evaluation of the equine heart and show the potential application of quantitative two dimensional echocardiography in the living horse.
This study was designed to evaluate the accuracy of two-dimensional echocardiography (2DE) in determining the left ventricular volume (LVV) of the horse in vitro. After examining the shape of the left ventricular silicon rubber casts of four equine hearts, two modified Simpson's rule methods (Model A and Model B) as combinations of conical shapes and one biplane area-length method as a single cone (Model C) were chosen for volume calculations. One long axis and three short axis planes were used for linear and area 2DE measurements, respectively. The ventricular length (L) was calculated from the chordal length (CL) by using a linear regression equation (L = 5.54 + 1.83 CL) obtained by anatomical measurement of these two parameters on 40 normal hearts. The LVV was calculated in 15 formalin-fixed hearts from 2DE measurements with the three geometric models. Left ventricular casts were then made using silicon rubber, and their volumes were determined by water displacement. The calculated volumes were plotted against cast volumes with linear regression analysis. All calculated LVVs correlated well with the cast LVVs (R = 0.921 to 0.957; P less than 0.001). The highest correlation was provided by Model A which best represented the shape of the left ventricle. This model consisted of a truncated cone bordered by the area at the level of the mitral valve and by the area at the level of the chordae tendineae, plus a cone the base of which was the area at the level of the papillary muscles. The results demonstrate the applicability of 2DE for equine LVV determinations in vitro, similar to other species.(ABSTRACT TRUNCATED AT 250 WORDS)
Because of its apparent success in relieving symptoms, especially pain, anterior mandibular repositioning therapy is a popular mode of nonsurgical treatment for patients with painful, clicking internal derangement of the temporomandibular joint. Posterior open bites are a frequent consequence of such therapy and may necessitate either continued appliance wear or closure by equilibration, prosthetics, or orthodontics. The anatomic and functional changes that occur subsequent to mandibular repositioning during orthodontic closure of the posterior open bite are not well understood. A case of a patient with a Class II, deep bite malocclusion and painful internal derangement of the TMJ is presented. Transcranial and cephalometric radiographs, arthrograms, and mandibular movement recordings were obtained before treatment and after both repositioning therapy and orthodontic treatment. Regarding occlusal improvement and pain relief, the treatment was successful. However, not all of the changes that occurred during repositioning therapy were maintained after orthodontic treatment. The strategy used in this case (mandibular repositioning/orthodontic finishing) was evaluated by an examination of these anatomic and functional changes with a discussion centered on the possible mechanisms involved.
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The radiographic procedures used for examination of the facial area and paranasal sinuses of 235 horses are reported. Clinical indications for these examinations and the diagnoses made are reviewed. Unilateral nasal discharge was the commonest reason for radiography, accounting for about one third of cases, most of which had radiological signs of paranasal sinus disease recognisable on erect lateral films. Oblique projections were required to obtain further information about the maxillary dental arcades and ventro-dorsal views demonstrated sinus expansion and extension of disease into the nasal cavity. In 24 horses with bilateral nasal discharge, the origin was usually shown to be in the lower respiratory tract and radiographic abnormalities were found in only 20 per cent of cases. Facial swelling was a feature of 25 per cent of cases; the commonest causes were premolar periapical disease, best shown on oblique views with the patient recumbent, and suture periostitis, easily demonstrated on erect lateral films. Other causes of facial swelling, which required multiple radiographic projections for evaluation, were sinus cysts and tumours and peripheral soft tissue masses. Epistaxis for which no cause could be found in the lower respiratory tract was the indication for radiography in a further 10 per cent of cases. In almost half of these a radiopaque shadow representing an ethmoid haematoma could be seen on an erect lateral film. A sinus cyst and a tumour were also recorded but most other causes of epistaxis failed to produce radiographic signs.(ABSTRACT TRUNCATED AT 250 WORDS)
The radiographic findings in 167 horses subjected to radiography of the facial area, nasal cavity and paranasal sinuses are recorded. Cases were grouped according to clinical diagnosis and the common and disparate radiographic features between and within groups are discussed. Dental disease occurred most frequently and accounted for about 30 per cent of cases, most of which had periapical infection. This disorder presented as two distinct clinical entities in almost equal numbers affected teeth with roots rostral to the maxillary sinus usually produced facial swelling, whereas those with roots within the sinus were generally associated with nasal discharge as a result of secondary sinusitis. In the former group periapical changes could readily be identified on radiographs, but in the latter group affected teeth could be recognised with confidence in only about half the cases. Primary sinusitis was the commonest specific condition recorded and accounted for 32 cases, three of which were mycotic. Using lateral erect projections, comparison of the radiographic features of primary sinusitis and sinusitis secondary to dental disease showed some useful differentiating signs. In four ponies, rhinitis associated with sinusitis led to disruption of the intra-nasal structures but mycotic rhinitis, nasal ulceration and an intra-nasal foreign body produced no radiographic abnormalities. Sixteen cases of suture periostitis were recorded, with varying degrees of new bone formation, and of 13 animals presented for evaluation of trauma, pre-diagnosed fractures were demonstrated in 10 and complications due to sinusitis in three.(ABSTRACT TRUNCATED AT 250 WORDS)
The clinical and radiographic features of 15 cases of paranasal sinus cysts are described. Breed, sex and side frequency were unremarkable but two distinct categories of age incidence emerged. Onset of signs had occurred before one year of age in three cases, while all but two of the remaining 12 animals were older than nine years. The most common clinical signs were nasal airway obstruction, facial swelling and nasal discharge, often occurring in combination. Radiographic changes were recorded in all horses. Sinus opacification was a consistent finding and in several cases the bone surrounding the sinus had increased in thickness. Increase in intra-maxillary sinus pressure was demonstrated by septal displacement on ventro-dorsal radiographs in almost half the cases. Less common signs included expansion, free fluid accumulation within the affected sinus, dental distortion and displacement and mineralisation. Two horses were destroyed without treatment but in 13 animals surgical exploration was performed. Two of these were destroyed, one at the time of surgery and one five days postoperatively. In the remaining 11 cases, all accessible parts of the cyst were removed through a facial flap and drainage to the nasal meati was established. All these horses recovered satisfactorily and were followed up for periods between three months and six years without evidence of recurrence. Thirteen cysts arose in the caudal maxillary sinus and one each in the frontal and rostral maxillary compartments. Histopathological examination of portions of the cyst walls suggests that, like ethmoidal haematomas, they may originate from episodes of haemorrhage beneath the upper respiratory tract mucosa.