The effect of a surgically created shunt between the corpus cavernosum penis and corpus spongiosum penis of stallions on erectile and ejaculatory function.

OBJECTIVE: To evaluate the effect of a shunt created between the corpus cavernosum penis (CCP) and corpus spongiosum penis (CSP) on erectile and ejaculatory function of normal stallions and to verify persistence of the shunt. STUDY DESIGN: The capability of stallions to develop an erection and to ejaculate was evaluated before and after creation of a corporeal shunt. Persistence of the shunt was determined by dye injection into the CCP at necropsy. ANIMALS: Six stallions. METHODS: A CCP-CSP shunt was created in five stallions. Semen was collected before and 4 to 14 weeks after surgery, before the horses were euthanatized. Dye was injected into the CCP to determine persistence of the shunt. Dye was also injected into the CCP of a control stallion. RESULTS: All stallions had normal erectile and ejaculatory function before and after surgery. Dye, injected into the CCP, entered the CSP in three of five treated stallions, demonstrating persistence of the shunt, whereas in two stallions, dye was found only in the CCP, indicating closure of the shunt. No dye was detected in the CSP of the control stallion. CONCLUSIONS: Creation of a corporeal shunt does not interfere with normal erection and ejaculation of stallions. Shunt closure is not necessary for stallions to retain normal erectile and ejaculatory function. CLINICAL RELEVANCE: Failure of a stallion affected by priapism to achieve normal erection or to ejaculate after creation of a corporeal shunt would likely be because of damage to corporeal tissue than from an effect of the shunt.

Pathophysiology of acquired dental diseases of the horse.

Periodontitis, infundibular necrosis, and periapical infection are dental diseases commonly affecting adult horses. Routine dental examinations and care may help to prevent these diseases. Further investigation of the treatment of horses with these diseases using local antimicrobial therapy, restorative dentistry, and endodontic therapy is needed. An understanding of the pathogenesis of these diseases aids in diagnosis and treatment. Gingival hyperplasia and odontogenic tumors are uncommon but should remain in a list of differential diagnoses when examining a horse with pertinent clinical signs. Recognition of odontogenic tumors as early as possible may facilitate surgery. Examination of the oral cavity of foals beyond the neonatal period should allow identification of brachygnathia and timely treatment when indicated.

Cobalt 60 radiotherapy for treatment of squamous cell carcinoma of the nasal cavity and paranasal sinuses in three horses.

Three adult horses underwent aggressive treatment of squamous cell carcinoma of the nasal cavity and paranasal sinuses, using course-fractionated cobalt 60 radiotherapy. Squamous cell carcinoma of the nasal cavity and paranasal sinuses is not commonly diagnosed in horses. Historically, horses with this type of neoplasm have not been treated or have undergone some form of surgery. The prognosis for long-term survival or cure has been poor. Long-term results of cobalt 60 radiotherapy were good to excellent and exceeded those usually reported for horses treated surgically. On the basis of these results, use of radiotherapy for these neoplasms is recommended.

Case control and historical cohort study of diarrhea associated with administration of trimethoprim-potentiated sulphonamides to horses and ponies.

Trimethoprim-potentiated sulphonamides (TPS) are among the most frequently administered antimicrobials in equine medicine. Anecdotally, TPS has been implicated as a cause of mild to moderate diarrhea in horses. The purpose of this study was to document the prevalence of diarrhea in horses receiving TPS, to characterize the severity of the diarrhea, and to identify any other factors associated with the development of diarrhea. A 2-part study was designed to identify the prevalence of diarrhea associated with TPS in our clinic population. Part I was a case-control retrospective study of 135 records over a 10.5-year period from January 1, 1980 through June 30, 1990. Part II was a historical cohort study of 784 records over a 37-month period from July 1, 1990 through July 31, 1993. There was no significant difference in the occurrence of diarrhea associated with TPS therapy in either study. The occurrence of diarrhea was 21% and 3% in parts I and II, respectively. Significant factors identified in association with diarrhea in part I were duration of hospital stay, and antibiotic therapy other than TPS or penicillin. Significant factors identified in part II included other antibiotic therapy, penicillin therapy, and combined penicillin and TPS therapy. Diarrhea does occur after the administration of antibiotics, most likely because of the alteration of the patient's normal intestinal flora. Diarrhea was noted in association with administration of TPS in this study; however, its prevalence was not significantly different than that in horses receiving other antibiotics, such as penicillin and its derivatives.

Detection of bacteria in equine synovial fluid by use of the polymerase chain reaction.

Equine synovial fluid aliquots were inoculated with Salmonella enteritidis, Escherichia coli, Actinobacillus equuli, Staphylococcus aureus, and Streptococcus zooepidemicus to obtain approximate concentrations of 1000, 100, 10, and 1 colony forming U/mL. Synovial fluid aliquots were also inoculated with an unquantitated inoculum of Bacteroides fragilis and Clostridium perfringens. Inoculated synovial fluid was incubated in trypticase-soy broth or Columbia broth for approximately 12 hours. Then aliquots were removed for DNA extraction and polymerase chain reaction (PCR) analysis for detection of a 531 base-pair segment of bacterial DNA corresponding to a region of the 16S ribosomal gene. Duplicate samples of inoculated synovial fluid were prepared for microbial culture. Bacteria were detected in all samples inoculated with bacteria but not in control synovial fluid samples. Under experimental conditions there was no difference between microbial culture and PCR analyses for detection of bacteria. Experimentally, PCR was able to detect bacteria in synovial fluid within 24 hours of inoculation.

Double-plate fixation of comminuted fractures of the second phalanx in horses: 10 cases (1985-1993).

OBJECTIVE: To determine the technique used, and the outcome for, double-plate fixation of comminuted fractures of the second phalanx of horses. DESIGN: Retrospective analysis of medical records. ANIMALS: 10 horses with comminuted fractures of the second phalanx that were treated by use of double-plate fixation. PROCEDURE: Two 4- to 6-hole dynamic compression plates were abaxially placed to achieve arthrodesis of the proximal interphalangeal joint and fixation of the fracture of the second phalanx. RESULTS: Arthrodesis and fracture healing were detected in all horses. CLINICAL IMPLICATIONS: Horses with comminuted fractures of the second phalanx that are treated with double-plate fixation have an excellent prognosis for survival and use as broodstock, and have an increased potential for return to useful function.

Treatment of olecranon bursitis in horses: 10 cases (1986-1993).

Medical records of 10 horses with olecranon bursitis were reviewed to examine treatments, evaluate a technique for en bloc resection of the bursa in standing horses, and determine outcome of the horses after treatment. Before admission, 6 horses had been treated by needle aspiration of fluid from the mass, followed by injection of corticosteroids. Subsequent treatment for 2 of these 6 horses included open drainage and packing of the cavity with gauze soaked in 7% iodine solution. None resolved after these treatments. After admission to the hospital, 5 horses were treated medically and 5 were treated by en bloc resection of the bursa. One horse that had received intralesional injection of a radionuclide was lost to follow-up evaluation. One horse treated conservatively by open drainage and packing and 1 treated by injection of a radionuclide had resolution of the olecranon bursitis. Only 1 of these 2 horses had a cosmetic result. The acquired bursae decreased in size in 2 horses (1 treated with a corticosteroid and 1 with orgotein), but were still visible 7 and 46 months after treatment, respectively. The surgery site of 4 horses that were treated by en bloc resection healed by primary intention, and the owners of these horses were pleased with the cosmetic results. The suture line of 1 horse dehisced 5 days after surgery. Proliferative granulation tissue was removed on 2 occasions, and the site healed by second intention after 2 months. A small knot and some white hair remained at the surgery site.

Use of autogenous cancellous bone grafting in the treatment of septic navicular bursitis and distal sesamoid osteomyelitis in horses.

Six horses with septic navicular bursitis or distal sesamoid osteomyelitis were treated by means of surgical debridement and lavage, followed by packing of the wound created in the bottom of the foot with an autogenous cancellous bone graft. Two horses were euthanatized, one 18 months after surgery because of complications in the contralateral support limb, and one 68 days after surgery because of continuing severe lameness. Four horses were alive 9, 16, 21, and 42 months after surgery. One horse was used as a broodmare and did not have observable lameness. Two horses were being ridden. The remaining horse had improved markedly, but was still lame. It appears that cancellous bone grafts can be used successfully, in conjunction with debridement and antimicrobial treatment, in horses with septic navicular bursitis and distal sesamoid osteomyelitis.

Cauda equina syndrome, diskospondylitis, and a paravertebral abscess caused by Rhodococcus equi in a foal.

A 4-month-old male Quarter Horse was referred for evaluation of urinary incontinence. Physical examination revealed clinical signs consistent with cauda equina syndrome. Radiography revealed diskospondylitis of S2 through S4. Infected bone was surgically curretted, and drainage was established for an associated paravertebral abscess. Rhodococcus equi was isolated from specimens of bone and from fluid samples obtained from the paravertebral abscess. Bethanechol was administered to stimulate urination. Erythromycin and rifampin were administered for 120 days. The foal's neurologic dysfunction resolved completely. Two years after discharge, the horse remained neurologically normal and did not have apparent effects as a result of its previous disorder.

Ultrasonographic morphology of the bicipital tendon and bursa in clinically normal quarter horses.

The bicipital tendons and bursae of 25 healthy adult Quarter Horses were ultrasonographically examined. Cross-sectional images of the right and left bicipital tendons were obtained from each horse, using a 7.5-MHz transducer held in the frontal plane at the point of the shoulder. The bicipital tendon at the point of the shoulder appeared as a bilobate structure overlying the echogenic surface of the humerus. Median distance from the skin surface to the cranial surface of the tendon on the medial sagittal plane of the tendon was 23 mm (range, 16.5 to 30 mm); median distance on the lateral sagittal plane was 14 mm (range, 8.5 to 19 mm). Median distance from the skin surface to the tendon on the midsagittal plane of the tendon was 17 mm (range, 10.5 to 22 mm). Median cranial-to-caudal widths of the lateral and medial lobes of the tendon at their greatest dimensions were 20.5 mm (range, 18 to 27.5 mm) and 16 mm (range, 13 to 20.5 mm), respectively. The median cranial-to-caudal width of the central (midsagittal) portion of the tendon was 10 mm (range, 7 to 13.5 mm). The bicipital bursa was < or = 3 mm wide at all locations at which it was measured. Ultrasonographic imaging was easily performed and allowed evaluation of the bicipital tendon, bursa, and surface of the underlying humerus.

Lead foreign body arthropathy in a horse.

A diagnosis of degenerative joint disease secondary to an intra-articular metallic foreign body in the right metacarpophalangeal joint was made in a Quarter Horse gelding. Arthroscopy, performed to evaluate the joint and remove the foreign body, revealed yellow discoloration of the articular cartilage and synovium, and blunting and proliferation of the synovium. The foreign body was identified as a lead sphere. Microscopic examination of synovium revealed chronic synovitis, with accumulation of hemosiderin and multifocal, mild mineralization. Another pigment was evident extracellularly in the synovium. Lead arthropathy was diagnosed. Lead arthropathy results from the dissolution of intra-articular lead, causing signs of chronic pain, restricted motion, joint effusion, and synovial proliferation.

Stringhalt secondary to trauma to the dorsoproximal region of the metatarsus in horses: 10 cases (1986-1991).

A review of medical records was used to identify 10 horses in which stringhalt developed subsequent to trauma to the dorsal metatarsus. Six horses developed stringhalt within 3 months after injury, 3 horses developed stringhalt > 3 months after injury, and time from injury to stringhalt was unknown for 1 horse. Horses were treated with exercise, including daily hand-walking with pasture turnout, followed by lunging; or surgically, using lateral digital extensor myotenectomy. Of the horses treated with exercise, 1 had resolution of stringhalt, 2 improved but had residual stringhalt, and 1 had no change. Two of the horses having lateral digital extensor myotenectomy had resolution of stringhalt. Two of the remaining 3 horses treated surgically had varying degrees of improvement, and in 1 horse there was no change. Stringhalt is a potential complication following trauma to the dorsal metatarsal region. Potential causes include tendon adhesions enhancing tarsocrural joint flexion or abnormalities in the myotatic reflex caused by tendon injury that result in abnormal flexion of the tarsocrural joint.

Removal of the preputial diverticulum in swine.

A new technique for removal of the preputial diverticulum in swine was performed on 33 sexually intact male potbellied pigs, 12 domestic boar cadavers, and 4 domestic swine (2 sexually intact males and 2 barrows). With each pig under general anesthesia, the body and horns of the diverticulum were everted through the preputial orifice and excised. In some cases, the stump of the diverticulum was sutured. Remaining tissues were allowed to retract through the preputial orifice. The technique was more rapid than the conventional method because skin incision and blunt dissection were unnecessary. Although the technique was developed as a preventive sanitary procedure to accompany routine castration of pet pigs, it has application to domestic swine practice.

Technique for long-term ileal cannulation in ponies.

A T-cannula was fitted permanently into the ileum of ten mature ponies to quantify the role of the prececal and postileal segments of the digestive tract in equine nutrition studies. The ponies were anesthetized, positioned in left lateral recumbency, and the distal small intestine was exteriorized through a right paralumbar incision. A silastic T-cannula was inserted through a 2-cm longitudinal incision into the lumen of the ileum, on the antimesenteric surface, and sutured to the ileum. The stem of the cannula was exteriorized through a 2-cm circular skin incision, 6 cm caudal to the 16th rib. Nine ponies were alive with functional cannulas after six months. Primary complications associated with cannulation of the ileum were clinical signs of depression and dehydration produced by leakage of intestinal contents around the stem of the cannula. These complications were resolved with fluid and electrolyte therapy.

Growth of desulfovibrio in lactate or ethanol media low in sulfate in association with H2-utilizing methanogenic bacteria.

In the analysis of an ethanol-CO(2) enrichment of bacteria from an anaerobic sewage digestor, a strain tentatively identified as Desulfovibrio vulgaris and an H(2)-utilizing methanogen resembling Methanobacterium formicicum were isolated, and they were shown to represent a synergistic association of two bacterial species similar to that previously found between S organism and Methanobacterium strain MOH isolated from Methanobacillus omelianskii. In lowsulfate media, the desulfovibrio produced acetate and H(2) from ethanol and acetate, H(2), and, presumably, CO(2) from lactate; but growth was slight and little of the energy source was catabolized unless the organism was combined with an H(2)-utilizing methanogenic bacterium. The type strains of D. vulgaris and Desulfovibrio desulfuricans carried out the same type of synergistic growth with methanogens. In mixtures of desulfovibrio and strain MOH growing on ethanol, lactate, or pyruvate, diminution of methane produced was stoichiometric with the moles of sulfate added, and the desulfovibrios grew better with sulfate addition. The energetics of the synergistic associations and of the competition between the methanogenic system and sulfate-reducing system as sinks for electrons generated in the oxidation of organic materials such as ethanol, lactate, and acetate are discussed. It is suggested that lack of availability of H(2) for growth of methanogens is a major factor in suppression of methanogenesis by sulfate in natural ecosystems. The results with these known mixtures of bacteria suggest that hydrogenase-forming, sulfate-reducing bacteria could be active in some methanogenic ecosystems that are low in sulfate.

Anaerobic roll tube media for nonselective enumeration and isolation of bacteria in human feces.

Medium 10 (M10), developed for rumen bacteria and containing small amounts of sugars, starch, volatile fatty acids, hemin, Trypticase, yeast extract, cysteine, and sulfide, plus agar, minerals and CO(2)-HCO(3)-buffer, was used with the Hungate anaerobic method as a basal medium to evaluate the efficacy of various ingredients. Three-day-old colony counts from adults on normal diets (17 samples) were 0.55 x 10(11) to 1.7 x 10(11) per g (mean, 1.15 x 10(11)) for M10. Single deletion of volatile fatty acids, Trypticase, yeast extract, or sulfide did not reduce counts. Deletion of hemin or both Trypticase and yeast extract significantly lowered counts. Addition of fecal extract, rumen fluid, 1% dehydrated Brain Heart Infusion (BHI) or 2 to 6% liver infusion did not increase counts; 1% dehydrated bile or 3.7% BHI markedly depressed them. Decreasing the gas-phase CO(2) concentration from 100 to 5% with N(2) and correspondingly lowering the HCO(3) had little effect. Counts in supplemented Brewer Thioglycollate (Difco), BHI, and Trypticase soy agar were similar or lower than in M10; ease in counting was best in M10. Comparison of features of 88 predominant strains of fecal bacteria randomly isolated indicated that M10 supported growth of as many or more species of bacteria as compared to supplemented BHI. The results suggest that predominant bacteria of human feces, in general, are not as nutritionally fastidious as rumen bacteria and indicate that media for counts or isolation containing large amounts of rich organic materials are neither necessary nor desirable when adequate anaerobic techniques are used.