Feline discrete high-grade gastrointestinal lymphoma treated with surgical resection and adjuvant CHOP-based chemotherapy: retrospective study of 20 cases.

The aim of this retrospective study was to evaluate the outcome of cats treated with surgical intervention for a discrete intermediate-/high-grade gastrointestinal lymphoma prior to CHOP-based chemotherapy. Variables including sex, breed, haematocrit, white blood cell count, serum albumin concentration, clinical stage of disease, gastrointestinal obstruction and peritonitis were assessed for their effect on survival. Twenty cats met the inclusion criteria with three cats still alive at the time of data analysis. The overall median survival time (MST) was 417 days (range: 12-2962 days). The disease-free interval (DFI) was 357 days (range: 0-1585 days) with six cats still deemed in remission prior to death. Only clinical stage had a significant effect on both MST and DFI. Cats with discrete intermediate/high-grade gastrointestinal lymphoma that undergo surgical resection followed by adjuvant CHOP chemotherapy may achieve acceptable overall survival times.

Choledochotomy and primary repair of extrahepatic biliary duct rupture in seven dogs and two cats.

OBJECTIVE: To report clinical findings and outcome in dogs and cats undergoing choledochotomy or primary repair of extrahepatic biliary duct rupture. METHODS: Retrospective study of dogs (n=7) and cats (n=2) that had choledochotomy or primary bile duct repair. RESULTS: Extrahepatic biliary obstruction was confirmed at surgery in all cases. The underlying cause in four dogs and both cats was choledocholithiasis, two dogs had gall bladder mucocoeles with associated bile duct rupture, and one dog had inspissated bile obstructing the bile duct secondary to gall bladder carcinoid tumour. Three dogs and both cats had choledochotomies performed to relieve extrahepatic biliary obstruction, and four dogs with bile duct rupture underwent primary repair of the defect. One dog with a bile duct rupture was re-explored four days postoperatively and had suffered dehiscence of the repair; this rupture was re-repaired. All animals were discharged from the hospital, and did not have clinical recurrence of extrahepatic biliary obstruction. CLINICAL SIGNIFICANCE: Choledochotomy and primary repair of extrahepatic biliary duct rupture were associated with low perioperative morbidity and no mortality in this small cohort of cases. These techniques are reasonable options either alone or in conjunction with other procedures when bile duct patency cannot be re-established by catheterisation or bile duct discontinuity exists.

Brown-headed cowbirds (Molothrus ater) harbor Sarcocystis neurona and act as intermediate hosts.

We tested the hypothesis that brown-headed cowbirds (Molothrus ater) harbor Sarcocystis neurona, the agent of equine protozoal myeloencephalitis (EPM), and act as intermediate hosts for this parasite. In summer 1999, wild caught brown-headed cowbirds were collected and necropsied to determine infection rate with Sarcocystis spp. by macroscopic inspection. Seven of 381 (1.8%) birds had grossly visible sarcocysts in leg muscles with none in breast muscles. Histopathology revealed two classes of sarcocysts in leg muscles, thin-walled and thick-walled suggesting two species. Electron microscopy showed that thick-walled cysts had characteristics of S. falcatula and thin-walled cysts had characteristics of S. neurona. Thereafter, several experiments were conducted to confirm that cowbirds had viable S. neurona that could be transmitted to an intermediate host and cause disease. Specific-pathogen-free opossums fed cowbird leg muscle that was enriched for muscle either with or without visible sarcocysts all shed high numbers of sporocysts by 4 weeks after infection, while the control opossum fed cowbird breast muscle was negative. These sporocysts were apparently of two size classes, 11.4+/-0.7 microm by 7.6+/-0.4 microm (n=25) and 12.6+/-0.6 microm by 8.0+/-0 microm (n=25). When these sporocysts were excysted and introduced into equine dermal cell tissue culture, schizogony occurred, most merozoites survived and replicated long term and merozoites sampled from the cultures with long-term growth were indistinguishable from known S. neurona isolates. A cowbird Sarcocystis isolate, Michigan Cowbird 1 (MICB1), derived from thin-walled sarcocysts from cowbirds that was passaged in SPF opossums and tissue culture went on to produce neurological disease in IFNgamma knockout mice indistinguishable from that of the positive control inoculated with S. neurona. This, together with the knowledge that S. falcatula does not cause lesions in IFNgamma knockout mice, showed that cowbird leg muscles had a Sarcocystis that fulfills the first aim of Koch's postulates to produce disease similar to S. neurona. Two molecular assays provided further support that both S. neurona and S. falcatula were present in cowbird leg muscles. In a blinded study, PCR-RFLP of RAPD-derived DNA designed to discriminate between S. neurona and S. falcatula showed that fresh sporocysts from the opossum feeding trial had both Sarcocystis species. Visible, thick-walled sarcocysts from cowbird leg muscle were positive for S. falcatula but not S. neurona; thin-walled sarcocysts typed as S. neurona. In 1999, DNA was extracted from leg muscles of 100 wild caught cowbirds and subjected to a PCR targeting an S. neurona specific sequence of the small subunit ribosomal RNA (SSU rRNA) gene. In control spiking experiments, this assay detected DNA from 10 S. neurona merozoites in 0.5g of muscle. In the 1999 experiment, 23 of 79 (29.1%) individual cowbird leg muscle samples were positive by this S. neurona-specific PCR. Finally, in June of 2000, 265 cowbird leg muscle samples were tested by histopathology for the presence of thick- and thin-walled sarcocysts. Seven percent (18/265) had only thick-walled sarcocysts, 0.8% (2/265) had only thin-walled sarcocysts and 1.9% (5/265) had both. The other half of these leg muscles when tested by PCR-RFLP of RAPD-derived DNA and SSU rRNA PCR showed a good correlation with histopathological results and the two molecular typing methods concurred; 9.8% (26/265) of cowbirds had sarcocysts in muscle, 7.9% (21/265) had S. falcatula sarcocysts, 1.1% (3/265) had S. neurona sarcocysts, and 0.8% (2/265) had both. These results show that some cowbirds have S. neurona as well as S. falcatula in their leg muscles and can act as intermediate hosts for both parasites.

Diagnosis and surgical management of ureteral calculi in dogs: 16 cases (1990-2003).

AIMS: To examine the clinical signs, laboratory and radiographic findings, surgical technique, ureterolith composition, and post-operative outcomes in dogs managed surgically for ureterolithiasis to determine whether surgical removal of ureteroliths in dogs resulted in a positive clinical outcome. METHODS: The medical record database of a university veterinary hospital in Pennsylvania, USA, was searched for dogs that underwent surgery to remove obstructive ureteral calculi between 1990 and 2003. Records were reviewed for signalment, clinical history and examination findings, radiographic and laboratory test results, surgical technique, and ureterolith analysis. Follow-up information was obtained from telephone interviews with owners or referring veterinarians, or by reviewing the medical record of subsequent hospital visits. RESULTS: Sixteen dogs were included in this study; ten were neutered females, two intact females and four castrated males. Abdominal radiography revealed ureteral calculi in 14/16 dogs, renal calculi in 8/16, cystic calculi in 8/16, urethral calculi in 1/16, renomegaly in 6/16 and renal mineralisation in 5/16. Ureterolith type included struvite in six dogs, calcium oxalate in five, calcium phosphate in one, and a mix of struvite, calcium phosphate and calcium oxalate in another. Compared to dogs with non-struvite ureteroliths, those with struvite ureteroliths had a higher pre-operative white blood cell (WBC) count (25.6, SD 7 vs 17.6, SD 6 x 103 cells/mul; p=0.046), and were more likely to have a purulent discharge from the ureteral incision noted at the time of surgery (p=0.015). Following discharge, 14/16 dogs were re-evaluated. Median survival time was 904 days (range 2-1,876). Two dogs required additional surgery on the urinary tract. Four dogs died or were euthanised because of azotaemia and clinical signs related to the urinary system or non-specific signs of illness (vomiting, lethargy) at 8, 90, 333 and 904 days post-operatively. CONCLUSIONS: Surgical management of ureteroliths was successful and resulted in good long-term survival in the majority of dogs examined in this small study population. Similar proportions of calcium oxalate and struvite ureteroliths were identified. CLINICAL RELEVANCE: The use of the ureteral surgery may increase as the frequency of diagnosis of ureteroliths in dogs increases.

Canine gallbladder infarction: 12 cases (1993-2003).

A cohort of 12 dogs with severe transmural gallbladder necrosis is described. All dogs had cholecystectomies performed. In six dogs, perforation of the gallbladder was noted at surgery. Eight dogs survived the immediate postoperative period, and four dogs died. Histologically, inflammation was absent or minimal in all cases, suggesting that cholecystitis was not the cause of necrosis. Thrombi (n = 2) and atheromatous vascular changes (n = 1) represent possible vascular causes of this condition. The findings of coagulative necrosis in these 12 dogs are compatible with "gallbladder infarction," and the authors propose this term to describe the histopathologic appearance of the gallbladder.

Polycythemia vera: dental management considerations.

This article presents a case of dental treatment in a patient with polycythemia vera. Polycythemia vera is an uncommon myeloproliferative disease that can have hematologic and surgical implications. The concerns and consequences of dental care in these patients are discussed and recommendations for dental treatment are given.

Increased glucose use in the hypoglossal nucleus after hypoglossal nerve transection in aged rats.

We used [2-14C]deoxyglucose as a marker of increased metabolism of the hypoglossal nucleus after transection of its nerve. We studied this metabolism in 3-, 12-, and 24-month-old rats. We found an increase in glucose uptake in the control nucleus of 24-month-old rats which was significant when compared to that of 3-month-old rats. We also found a twofold increase in the difference between glucose uptake on the side of nerve transection compared to the control side in old rats.

Effect of extracts of injured nerve on initiating the regenerative response in the hypoglossal nucleus in the rat.

The uptake of 2-deoxy-[14C]glucose (2-DG) by motor neurons in adult rat hypoglossal nuclei was studied 3 days after subepineural injection of 'crude' soluble protein extracts from intact and injured peripheral nerves into normal hypoglossal nerves. Injured nerve extracts were obtained from 'proximal' and 'distal' segments of sciatic nerves which were transected between two ligatures 3 days earlier. In one group of animals the hypoglossal nerve (experimental) was injected with a particular nerve extract. In another group of animals (control) the hypoglossal nerve was injected with physiological saline solution. Both proximal and distal nerve extracts caused a significant increase in 2-DG uptake. In turn, no 2-DG was detected after treatment with uncut nerve extracts or saline. These findings support the ideas that a substance(s) produced upon nerve injury is taken up by the axons and transported to the cell bodies where it triggers certain metabolic regenerative changes.

Glucose and leucine uptake in the hypoglossal nucleus after hypoglossal nerve transection with and without prevented regeneration in the Sprague-Dawley rat.

We studied [14C]2-deoxyglucose and [14C]leucine uptake in the rat hypoglossal nucleus after hypoglossal nerve transection and when regeneration was prevented by placing a nylon ligature around the nerve proximal to the cut. Glucose and leucine uptake increased after nerve transection in both the animals with nerve transection alone and with the ligature. Both the glucose and leucine uptake increased more in animals with the ligature. The glucose and leucine uptakes returned to normal at 30 and 45 days, respectively, after transection alone and at 60 days in animals in whom regeneration was prevented with a ligature. This suggests that there is a more powerful stimulus to regeneration when regeneration is prevented but that some mechanism turns the process off after a fixed time.

Fasting increases glucose and leucine uptake during regeneration of the hypoglossal nerve in the rat.

Glucose uptake is increased during motoneuron regeneration. Since this glucose is probably used as an energy source for axonal regeneration we postulated that hypoglycemia might interfere with motoneuron regeneration. In order to partially test this hypothesis we attempted to induce moderate hypoglycemia by fasting rats for 3 days between the time of hypoglossal nerve transection and the time of [14C]2-deoxyglucose (2-DG) and [14C]leucine measurement. We transected one hypoglossal nerve, leaving the other intact, and measured the glucose uptake quantitatively or leucine uptake semiquantitatively in the hypoglossal nucleus. We found that both glucose and leucine uptake were increased in the hypoglossal nuclei during regeneration of the nerve in the fasted animals above that in the normally fed animals. This suggests that fasting creates a deficit of glucose and perhaps leucine which induces increased uptake.

Role of electrical activity in axotomy-induced increased glucose use.

Glucose use as demonstrated by 2-deoxyglucose autoradiography increases in the hypoglossal nucleus after axotomy of the hypoglossal nerve. There are several possible explanations for this increase, including increased energy metabolism to support increased protein, RNA, and lipid synthesis during regeneration or, alternatively, increased electrical activity associated with the site of nerve transection or alterations in the neurolemma. To evaluate the possible role of electrical activity, we recorded spike activity in the hypoglossal nucleus after axotomy and evaluated glucose uptake in the hypoglossal nucleus after xylocaine application to the proximal nerve stump. There was no evidence from these experiments that an increased number of action potentials is responsible for the increased glucose use after axotomy.

Blockade of retrograde axonal transport delays the onset of metabolic and morphologic changes induced by axotomy.

Axotomy-induced increase in 2-deoxyglucose (2-DG) uptake by motor nuclei and neuronal chromatolytic changes were studied after subepineural injection of colchicine into the motor nerve. Hypoglossal nuclei of either cats or rats were axotomized bilaterally, while one of the nerves was injected with colchicine or saline proximal to the site of nerve transection and the other was left intact or injected with saline. Colchicine abolished or decreased the uptake of 2-DG by axotomized nuclei and delayed the onset of chromatolysis. The decrease in 2-DG uptake was observed in rat hypoglossal nuclei between 24 and 48 hr but not 5 days after drug treatment. In turn, a delay in the onset of chromatolysis was observed in cat hypoglossal nuclei at 14 days but not 30 days after treatment. Saline did not prevent chromatolysis nor the increased uptake of 2-DG. Colchicine injected intraneurally in intact preparations did not result in chromatolysis or in increased 2-DG uptake. Following colchicine injection, the drug remained localized near the site of injection and blocked retrograde axonal transport of horseradish peroxidase in the hypoglossal nerve. These findings suggest that the onset of chromatolysis and of the increase in 2-DG uptake after axotomy are partly dependent upon retrograde axonal transport.

Retrograde axonal transport mediates the onset of regenerative changes in the hypoglossal nucleus.

The hypoglossal nucleus was assayed for [14C]2-deoxyglucose uptake 24 h after axotomy with and without colchicine injections into the nerve proximal to the nerve transection. Colchicine effectively blocked the usual increase in [14C]2-deoxyglucose uptake seen after axotomy. The drug also blocked the transport of horseradish peroxidase from the tongue muscles to the hypoglossal nucleus which otherwise occurred within this time period. Distribution of [3H]colchicine showed that the drug remained localized within the nerve close to the injection point. These results suggest that retrograde axoplasmic flow is involved in the mechanism which initiates hypoglossal neuron regeneration.