Benign cranial mediastinal lesions in three cats

Cranial mediastinal lesions were detected in three cats, associated with respiratory impairment (case one), spontaneous pneumothorax (case two) and myasthenia gravis (case three), respectively. On gross and histological examination, the first case was considered either a lymphangioma or a branchial cystic mass of the thymic region of the mediastinum; a cystic lesion was suggested by sonographic detection of multiple anechoic cavitations within a circumscribed mass, while fine needle aspiration cytology excluded lymphosarcoma. The second case was diagnosed histologically as a cystic thymoma, but the third case was not examined microscopically. The masses were amenable to surgical excision in the first two cats, while this proved unnecessary in the third case because of resolution following treatment with dexamethasone. Corticosteroid responsiveness was unhelpful in distinguishing between these benign lesions and lymphosarcoma, as in two cases there was a partial or complete response to dosing with prednisolone or dexamethasone. These cases are presented to emphasise that conditions other than lymphosarcoma can produce cranial mediastinal lesions in cats, and that the prognosis for surgical treatment of lymphangiomas, multilocular thymic cysts and cystic thymomas can be excellent.

Rickets in a litter of racing greyhounds

Rickets was diagnosed in six 14-week-old racing greyhound littermates presented with musculoskeletal disease. Physical findings included listlessness, profound muscle weakness, lameness, lateral bowing of the antebrachii and focal hard swellings proximal to the tarsi and carpi. Radiological findings included generalised osteopenia, axial and radial thickening of growth plates, and "cupping' of the adjacent metaphyses; the distal ulnar growth plates were most severely and consistently affected. The diagnosis was confirmed by demonstrating subnormal concentrations of 25-hydroxycholecalciferol in serum samples collected at admission. The pups' diet consisted of an inexpensive generic kibble formulated for adult dogs, porridge, milk, pasta, minced beef, vegetables and a small quantity of calcium carbonate powder. The pups were successfully treated by feeding a nutritionally complete, vitamin D-containing ration formulated for growing pups. Bilateral growth retardation of distal ulnar physes occurred as a sequel in one pup.

Asymptomatic carriage of Cryptococcus neoformans in the nasal cavity of dogs and cats

Nasal washings, obtained from a random source of dogs and cats, were concentrated by centrifugation and plated onto bird seed agar containing antibiotics. Cryptococcus neoformans var. neoformans was isolated from eight of 56 dogs (14%) and three of 45 cats (7%). More than 100 colonies of C. neoformans were present on the plates from seven of the 11 positive animals. Absence of cryptococcal antigen in the serum of these animals, and failure to demonstrate yeast-like organisms or significant pathology in nasal biopsies, suggests that the nasal cavity of these animals was not infected by C. neoformans but rather that blastoconidia and/or basidiospores were carried asymptomatically. These findings are discussed in relation to the likelihood of the upper respiratory tract being the primary site for cryptococcal infection in dogs and cats.

Lung capillary changes in hepatic cirrhosis in rats

The hypoxemia of the hepatopulmonary syndrome may result from dilated intrapulmonary vascular segments. Knowledge of the size, density, and branching frequency of the lung capillaries might confirm this hypothesis and suggest that the pathogenesis may involve vascular dilatation or angiogenesis. To investigate these changes, the common bile duct of rats was tied off to cause biliary cirrhosis. Later (4 wk), the pulmonary vasculature of these animals was cast, and the casts were studied with scanning electron microscopy. In the ligated animals, evidence for enhancement of the bronchial to pulmonary circulation was found: cast vasa vasorum of the pulmonary arteries and cast bronchial veins emptying into pulmonary veins. Ligated animals had more adherent intracapillary cells per alveolus than the sham-operated animals. The diameters of all capillary beds were larger in the ligated animals. The alveolar capillary density was increased, but the branching frequency was not. A few areas suggesting angiogenesis were found. Induction of biliary cirrhosis enhances the pulmonary-systemic circulation, increases intracapillary adherent cells, capillary diameter, and density, and may be associated with angiogenesis.

Stage IV ovarian cancer: impact of surgical debulking

OBJECTIVE

To evaluate the influence of surgical debulking performed on patients with Stage IV ovarian cancer and to determine prognostic factors which identify pts who may benefit from aggressive initial surgical debulking.

METHODS

A retrospective chart review was conducted (1/1/87-12/31/93). Eligible patients included all women with FIGO Stage IV ovarian cancer. Clinical information abstracted included age at diagnosis, histology type, tumor grade, criteria for Stage IV classification, surgical procedure performed, and tumor residuum. Optimal surgical status was defined as < or = 2 cm residual disease. Chemotherapy treatment was recorded, as was follow-up. Survival estimates were computed by Kaplan-Meier method with differences in survival calculated by the log-rank test. The Cox proportional hazards regression model was used to identify independent variables which were associated with an improved survival rate.

RESULTS

One hundred five women were found in our database with Stage IV ovarian cancer and 97 had complete information available. Median age of the patients was 57 years (range 24-81 years). Papillary-serous histology was found in 55/97 patients (57%) and 50 patients (52%) had grade 3 tumors. Forty-one of 97 patients (42%) had malignant pleural effusion and 20/97 (21%) had liver metastases. Ninety-two patients underwent a primary attempt at surgical debulking and 40/92 were optimally debulked. Twenty-one of 41 patients (51%) with pleural effusion were optimally debulked compared to 20/51 (39%) with other criteria for Stage IV disease (P = NS). Overall median survival was 21 months; optimally debulked patients' median survival was 40 months compared to 18 months for patients with bulky residual disease (P = 0.01). The survival advantage for optimally debulked patients was statistically significant for the two subgroups of patients with and without malignant pleural effusion. In the multivariate analysis only age less than 65 years and optimal debulking were independent predictors of outcome.

CONCLUSIONS

Surgical debulking appears to be an important determinant of prognosis in women with Stage IV ovarian cancer, including patients with malignant pleural effusion.

The method of subliminal psychodynamic activation: do individual thresholds make a difference?

The present experiment investigated the effects of subliminal psychodynamic stimuli on anxiety as measured by heart rate. Following an anxiety-inducing task, male and female subjects were tachistoscopically shown, at their subjective thresholds, one of five subliminal stimuli, MOMMY AND I ARE ONE, DADDY AND I ARE ONE (symbiotic messages). MOMMY HAS LEFT ME (abandonment message), I AM HAPPY AND CALM (positively toned but nonsymbiotic phrase), or MYMMO NAD I REA ENO (control stimulus). It was hypothesized that men would exhibit a greater decrease in heart rate after exposure to the MOMMY stimulus than the control message. No definitive predictions were made for women. The abandonment phrase was expected to increase heart rate. A positively toned message was included to assess whether its effects would be comparable to those hypothesized for the MOMMY message. The results yielded no significant effects for stimulus or gender and so provided no support for the hypotheses.

A latex cryptococcal antigen agglutination test for diagnosis and monitoring of therapy for cryptococcosis

A latex cryptococcal antigen agglutination test (LCAT) was performed on sera obtained during the first 14 days of treatment from 58 animals (46 cats, 9 dogs, 2 koalas and 1 long billed corella) with cryptococcosis. The same commercial kit was used for all samples, and most serum samples were treated with pronase before testing. Sera from all 58 cases tested positive with the qualitative LCAT protocol (using undiluted sera), while sera from all 26 cats without cryptococcosis tested negative. Titres determined using the quantitative protocol ranged from 1 to > or = 131 072 (median titre between 2048 and 4096), with 57 of 58 cases (including all 8 animals that presented for neurological signs) having titres > or = 2 and thus considered positive according to the manufacturer's recommendations. The LCAT titre was positively correlated with disease severity (r = 0.4169; P = 0.0011), and patients with disseminated skin and/or lymph node involvement had significantly higher titres than those that did not (P = 0.0157). The presence of neurological signs, the species of the patient, concurrent viral disease (in cats) and the biotype of the isolate had no significant association with the LCAT titre. Cats that died of active cryptococcosis despite treatment did not have significantly higher titres (P = 0.3010) than those that responded to treatment. Sequential LCAT determinations obtained in 37 patients during treatment provided a useful quantitative indication of clinical progress, although the decline in titre lagged somewhat behind clinical improvement. Generally, the antigen titre declined by 2 to 4 fold per month during successful therapy. Although there are insufficient data to make unequivocal recommendations, we suggest that either antifungal therapy be continued until the LCAT titre declines to less than 1, or therapy be discontinued after a 32 fold or greater reduction in titre, with periodic monitoring of the serum antigen titre. Treatment of serum samples with pronase substantially increased the sensitivity of the LCAT.

Suspected drug eruption in seven dogs during administration of flucytosine

7 of 8 dogs receiving combination drug therapy consisting of flucytosine together with amphotericin B and/or a triazole for cryptococcosis or aspergillosis developed cutaneous or mucocutaneous eruptions during the course of treatment. Lesions resolved in all cases following discontinuation of flucytosine despite continued administration of other antifungals, suggesting the eruption was referable primarily to the flucytosine component of therapy. Lesions developed 13 to 41 days (median 20 days) after commencing flucytosine (105 to 188 mg/kg/day divided and given every 8 h; median dose rate 150 mg/kg/day). The cumulative dose of flucytosine given prior to the first signs of the drug eruption ranged from 1.7 to 6.8 g/kg (median 2.3 g/kg). The eruptions consisted of depigmentation, followed by ulceration, exudation and crust formation. The scrotum was affected in all 4 male dogs, the nasal plane in 6 of 7 cases, while the lips, vulva, external ear canal and integument were involved in a smaller number of cases. There was considerable variation in the severity of lesions, with changes being most marked when flucytosine was continued for several days after lesions first appeared. Some dogs experienced malaise and inappetence in association with the suspected drug eruption. Healing took a variable period, typically in excess of 2 weeks after discontinuing flucytosine, with up to 2 months being required for total resolution of the lesions. All lesions resolved eventually without scarring or permanent loss of pigment.

Bleeding from gastric antral vascular ectasia in marrow transplant patients

BACKGROUND

Gastric antral vascular ectasia (GAVE) leads to blood loss in the disorders of "watermelon stomach" and portal gastropathy, but is not a commonly recognized complication of marrow transplantation.

METHODS

GAVE was diagnosed when capillary ectasia, focal capillary thromboses, and fibromuscular hyperplasia were identified in antral mucosal biopsy specimens. Marrow transplant patients bleeding from GAVE were reviewed to ascertain common variables in their pretransplant, posttransplant, and bleeding course.

RESULTS

Six patients developed bleeding due to GAVE. The onset of bleeding was 18 to 94 days after transplant and required an average of 37 U of blood (range, 2 to 130 U). Two patients stopped bleeding after restoration of platelet counts. Two patients had surgical antral resections; both died of multiorgan failure after surgery. Two patients had successful endoscopic laser ablation of vascular lesions and survived. Factors possibly associated with GAVE included male gender, VOD of the liver, oral busulfan as part of the conditioning regimen, and growth factor use after transplant.

CONCLUSIONS

GAVE was a cause of gastric bleeding in six patients with marrow transplant patients. Restoration of platelet counts and endoscopic laser photocoagulation are the therapies of choice for ongoing bleeding in these patients.

Effects of subliminal symbiotic stimuli on anxiety reduction

The present study assessed the effectiveness of subliminal psychodynamic stimuli in reducing anxiety. 50 male and 50 female college students were tachistoscopically exposed to one of five stimuli: MOMMY AND I ARE ONE, DADDY AND I ARE ONE, I AM HAPPY WITH MYSELF, ONE, or a control stimulus MYMMO NAD I REA ENO. It was hypothesized that men would show a significant decrease in anxiety to the MOMMY stimulus, while women were expected to respond favorably to either the MOMMY or DADDY stimulus, or to both. Results showed that the subliminal stimuli did not produce differential effects on anxiety. This finding did not support previous claims for subliminal psychodynamic activation that the stimulation of symbiotic fantasy with the maternal figure produces positive behavioral effects. Despite this negative finding women's response to the MOMMY message was predicted by measures of self-perception.

Natural environmental sources of Cryptococcus neoformans var. gattii

We sought evidence for new environmental sources of Cryptococcus neoformans var. gattii by random amplification of polymorphic DNA (RAPD) analysis of isolates from 29 animals with a restricted territorial range in five Australian states. Twenty-three of the 29 isolates and 45 of 45 eucalypt isolates tested previously exhibited one RAPD profile, VGI. RAPD profile VGII was identified in 6 of 17 isolates from domesticated species but in none of 12 native species. Four VGII isolates originated from an area of Western Australia with no natural stands of known eucalypt host, indicating the existence of at least one unrecognized natural source of C. neoformans var. gattii.

Combination chemotherapy of canine and feline cryptococcosis using subcutaneously administered amphotericin B

Six cases (3 cats, 3 dogs) of cryptococcosis were cured using combination chemotherapy that included amphotericin B. We developed a simple, practical and inexpensive method of administering amphotericin B as a subcutaneous infusion during the treatment of these patients. For this, the calculated dose of amphotericin B (0.5 to 0.8 mg/kg) was added to 400 mL, for cats, or to 500 mL, for dogs, of 0.45% saline containing 2.5% dextrose. These amounts were given subcutaneously 2 or 3 times weekly over several months, to a total cumulative dose of 8 to 26 mg/kg body weight. Subcutaneous infusions were generally well tolerated by the animals, although concentrations of amphotericin B in excess of 20 mg/L resulted in local irritation. This protocol enabled the administration of larger, and thus more effective, quantities of amphotericin B without producing marked azotaemia.

Arterio-venous shunting and proliferating new vessels in acute painful neuropathy of rapid glycaemic control (insulin neuritis)

Insulin neuritis, or painful neuropathy following rapid improvement in glycaemic control, is well recognised but its aetiology is unclear. An understanding of the processes involved in the genesis of acute painful neuropathy of rapid glycaemic control may give an insight into the early pathogenetic factors leading to diabetic nerve damage in general. We have identified five subjects with insulin neuritis including one who developed severe autonomic neuropathy following treatment with insulin. Subjects underwent: 1) assessment of neuropathic symptom and deficit scores; 2) quantitative sensory and electrophysiological studies and 3) sural nerve epineurial vessel photography and fluorescein angiography in vivo. The sural nerve photographs were independently graded by an ophthalmologist. All subjects with insulin neuritis presented with severe sensory symptoms but clinical examination and electrophysiological tests were normal except in the subject with the severe autonomic neuropathy in whom all the tests were abnormal. On nerve photography, there was an abundance of epineurial nutrient vessels although these showed severe abnormalities including arteriolar attenuation, tortuosity and arterio-venous shunting in all subjects. Proliferating neural 'new vessels' which bear striking similarities to those found in the retina and that were more leaky to fluorescein than normal vessels, were observed in three subjects. Venous distension and/or tortuosity was also observed in three subjects and this was most marked in the subject with severe autonomic neuropathy. This study shows that epineurial nutrient vessel anatomy is abnormal in subjects with acute painful neuropathy of rapid glycaemic control, a condition previously thought to be purely metabolic in origin. The presence of epineurial arterio-venous shunting and a fine network of vessels resembling the new vessels of the retina, may lead to a 'steal' effect rendering the endoneurium ischaemic. This process may be important in the genesis of neuropathic pain, and further supports the importance of vascular factors in the pathogenesis of diabetic neuropathy.

Glomerulopathy in dogs with congenital portosystemic shunts

Kidney specimens from 12 dogs with congenital portosystemic shunts were examined histologically. Glomerulopathy of variable severity was present in the kidney sections of all 12. Marked irregular thickening of the glomerular capillary wall was the most prominent pathological change, the renal interstitium being largely unaffected. The severity of lesions was not correlated with the age of dogs at the time of necropsy. An immunoperoxidase technique failed to demonstrate significant IgA or IgG deposition in affected glomeruli. Proteinuria was generally mild or absent despite significant glomerular lesions, except in dogs with concurrent urinary tract infection.

Evaluation of factors affecting the accuracy of impressions using quantitative surface analysis

Impression material goes from a plastic to an elastic state during setting. Movement of the impression and excessive seating pressure during this transition can cause distortion in the impressions. The purpose of this study is to determine if the impression distortion is related to movement during setting or to distortion of the putty phase in the two-step impressioning technique. A master model of a maxillary quadrant of teeth was impressed using four different procedures: 1) one-step technique without movement (1S-NM); 2) one-step technique with movement (1S-M); 3) two-step technique without movement (2S-NM); and 4) two-step technique with movement (2S-M). An artificial oral environment and surface analysis technique of the Minnesota Dental Research Center for Biomaterials and Biomechanics were used to produce the impressions and measure their accuracy. A digitized image of the first premolar of the master model was aligned with a digitized image of the first premolar of each epoxy model using AnSur. The root mean squared difference (RMS) between the aligned images is a measure of the distortion. The corresponding RMS values for the different methods were: 1S-NM = 23.7 +/- 9.21; 1S-M = 20.4 +/- 3.9; 2S-NM = 20.5 +/- 7.7; 2S-M = 21.3 +/- 4.4. Statistical analysis using a two-way analysis of variance showed no difference at the 0.05 level of significance. Pairwise comparison using the Tukey method showed that neither technique (one-step vs two-step) nor movement is a significant factor. These results showed that low seating pressure will not cause any greater distortions in the two-step impression technique than in the one-step technique, and minor movement during the setting of the impression material will no cause distortion.

Ventricular septal defect repair in a small dog using cross-circulation

A haemodynamically significant ventricular septal defect was diagnosed in a 3-month-old male Cavalier King Charles Spaniel. A median sternotomy was performed and the 6.5 kg dog placed on cardiopulmonary bypass using pump-assisted cross-circulation. A 10 mm diameter peri-membranous ventricular septal defect was closed using a continuous suture of 4-0 polypropylene, via a 2.5 cm incision in the right ventricular outflow tract. The duration of cardiopulmonary bypass was 90 minutes. Complications in the immediate postoperative period were mild and easily managed.

Cryptococcosis in dogs: a retrospective study of 20 consecutive cases

The clinical and mycological findings in 20 consecutive cases of cryptococcosis evaluated between 1981 and 1995 were analysed retrospectively. Typically, young adult dogs (median age 2 years) of either sex were affected. Dobermann Pinschers and Great Danes were significantly over-represented in relation to other breeds and crossbred dogs, and there was no trend for cryptococcosis to be acquired at a particular time of year. Cryptococcus neoformans was cultured from 18 dogs, with 16 isolates further characterized. Of these, C. neoformans var. neoformans was isolated from 12 cases, while the remaining four strains were C. neoformans var. gattii. Dogs with C. neoformans var. gattii infections resided in rural (two cases) or suburban (two cases) environments. Ten dogs were presented as a result of infection of structures inside, adjacent to, or contiguous with the nasal cavity. Seven dogs were presented primarily for signs of central nervous system disease, of which at least three also had cryptococcal rhinosinusitis. One dog had cryptococcal pneumonia and also possible mycotic rhinitis, another had disseminated disease with lymph node and skin involvement, while the last dog was presented for vomiting referable to cryptococcal mesenteric lymphadenitis. Treatment consisting of surgery and/or antifungal drug therapy was successful in the majority of animals in which it was attempted, including two of three cases with meningo-encephalitis.

Catecholamines in human keratinocyte differentiation

Human keratinocytes have the capacity to synthesize catecholamines from L-tyrosine, which in turn is produced from L-phenylalanine via phenylalanine hydroxylase. This enzyme activity is controlled by the supply of the essential cofactor/electron donor (6R)5,6,7,8 tetrahydrobiopterin (6-BH4). Undifferentiated keratinocytes express high levels of the rate-limiting enzymes for the de novo synthesis of 6-BH4, i.e., GTP-cyclohydrolase-1, and for its recycling, i.e., 4a-hydroxytetrahydrobiopterin dehydratase. As a consequence of 6-BH4 synthesis, phenylalanine hydroxylase is activated, yielding L-tyrosine, which in the presence of excess 6-BH4 turns on the biosynthesis of catecholamines via the rate-limiting enzyme tyrosine hydroxylase. Therefore, undifferentiated keratinocytes contain high levels of the catecholamine system yielding sufficient levels of norepinephrine and epinephrine, required for the induction of beta-2-adrenoceptors. Stimulation of beta-2-adrenoceptors by epinephrine causes a rise in intracellular calcium via extracellular influx. This event corresponds with keratinocyte differentiation. In differentiated keratinocytes, all enzyme activities involved in 6-BH4, L-tyrosine, and epinephrine biosynthesis are decreased, resulting in significantly lower levels of epinephrine and a concomitant decrease in the expression of beta-2-adrenoceptors. These data strongly suggest a connection between catecholamine biosynthesis, beta-2-adrenoceptor expression, calcium flux, and the differentiation of keratinocytes in human epidermis.

Post-prandial serum bile acid concentrations and ammonia tolerance in Maltese dogs with and without hepatic vascular anomalies

Post-prandial serum bile acid concentrations were measured in 200 Maltese dogs in an attempt to identify those with subclinical portosystemic shunts. Five of these were later shown to have hepatic pathology or abnormal liver function. In the other 195 Maltese, bile acid concentrations ranged from 1 to 362 mumol.L-1 (mean +/- SD, 70 +/- 50 mumol.L-1; median, 65.0 mumol.L-1). Of these, 79% were above the reference range (0 to 31 mumol.L-1) established from 23 mixed-breed control dogs. It was therefore not possible to determine the prevalence of subclinical portosystemic shunts on the basis of bile acid determinations. Further investigation of liver function was performed to investigate why bile acid concentrations were increased in these dogs. Rectal ammonia tolerance tests were normal in 102 of 106 Maltese tested and liver samples (11 dogs) and plasma biochemistry profiles (9 dogs) demonstrated no significant hepatic disease or dysfunction. Of 2 Maltese with hyperammonaemia after administration of ammonium chloride, one had a large congenital portosystemic shunt that was confirmed at surgery. In the other there were no macroscopic portosystemic communications, but a liver biopsy showed histological changes consistent with microscopic portovascular dysplasia. Total serum bile acid concentrations were consistently lower when assessed by high-performance liquid chromatography than by an enzymatic spectrophotometric method. This discrepancy was substantially larger in Maltese than in control dogs, suggesting the presence of an additional reacting substance in the serum of Maltese dogs.