Use of autogenous cancellous bone graft for treatment of osteolytic defects in the phalanges of three cattle.

Osteolytic defects were detected radiographically in the distal sesamoid bone of a 16-month-old Bralers heifer, in the middle phalanx of a 14-month-old American Gray Brahman bull, and in the distal phalanx of a 3-year-old American Gray Brahman bull. The articular cartilage was damaged in each animal because of osteolysis or pathologic fracture. After each animal was anesthetized and positioned in lateral recumbency, the lesions were curetted and packed with cancellous bone harvested from the same animal's tuber coxae. Basic postoperative management involved stall rest and immobilization of the graft site with a fiberglass cast (42 to 79 days), after which a support bandage was used for approximately 2 weeks. Recurrence of lameness has not been observed in these animals for 60 months, 58 months, and 21 months, respectively. These cases exemplify the benefit of using an autogenous cancellous bone graft for treatment of severe osteolysis of a digit in cattle.


Prepurchase evaluation of horses: 134 cases (1988-1990).

To quantify some components of prepurchase evaluations in horses, records from 134 evaluations performed during a 2-year period were reviewed and the outcome was determined via telephone follow-up interview. Sixty-two percent of the prepurchase evaluations had been performed at the clinic and 38% had been performed in the field by the ambulatory service. All evaluations included physical and lameness examinations, whereas radiography (49%), endoscopy (15%), nerve blocking (5%), transrectal palpation (3%), hematologic analysis (2%), electrocardiography (2%), drug testing for analgesic agents (2%), and ultrasonography of the flexor tendons (1%) were not always performed. Fifty-nine percent of horses evaluated at the clinic were radiographed, compared with 33% of horses evaluated in the field (P less than 0.05). Thirty-seven percent of horses evaluated were judged serviceable for their intended use. Thirty-five percent of horses evaluated at the clinic were assessed to be serviceable, compared with 41% of those evaluated in the field (P less than 0.05). Horses used for pleasure riding (48%) tended to be considered serviceable more often than horses used for more athletic endeavors (3-day eventing, 33%; hunter/jumper, 24%; show, 31%; dressage, 30%). The most common basis for finding a horse unserviceable was lameness (88%).(ABSTRACT TRUNCATED AT 250 WORDS)


Tarsal lameness of dairy bulls housed at two artificial insemination centers: 24 cases (1975-1987).

Degenerative joint disease of the tarsi was diagnosed in 20 of 24 Holstein bulls with tarsal lameness at 2 artificial insemination centers from 1975 to 1987. Each of the 2 centers housed about 100 bulls/yr. Of the 24 bulls with tarsal lameness, 22 were from the artificial insemination center designated as A, and 2 were from the center designated as B. Examination of the housing and management procedures revealed that center A had concrete floors with cuboidal-shaped yards, whereas center B had deep sand flooring, with long, narrow yards. The only other difference between the 2 centers was that center A used 1- and 2-year-old bulls as teasers for older, heavier bulls to mount, whereas center B used bulls that were at least 6 years old to withstand the stress placed on their hind limbs by the weight of bulls undergoing semen collection. Radiographic lesions of tarsi of bulls from both centers ranged from distention of the tibiotarsal joint pouch to hypertrophic degenerative osteoarthritis of the distal, intertarsal, and tarsometatarsal joints. It was concluded that the concrete flooring and the semen collecting practices were responsible for the high prevalence of tarsal lameness and degenerative joint disease of the tarsi in bulls housed at center A.


Immunodeficiency syndrome associated with wasting and opportunistic infection in juvenile llamas: 12 cases (1988-1990).

Immunodeficiency was diagnosed as the cause of severe debilitating disease characterized by weight loss, failure to grow, and persistent infections that failed to respond to treatment in 12 young llamas. The llamas were affected after maternal-acquired immunity had decreased; failure of passive transfer of immunoglobulins thus was not suspected. Areas of lymph nodes containing T lymphocytes were hypocellular, suggesting T-cell involvement. High serum immunoglobulin concentrations were not found, despite the existence of infectious disease, suggesting at least secondary B-cell involvement. Results of lymphocyte blastogenesis assays were suggestive of B- and T-cell involvement. It was not possible to determine whether the condition was inherited or acquired.


Leiomyosarcoma in dogs: 44 cases (1983-1988).

During a 5-year period, leiomyosarcoma was diagnosed in 57 dogs. Forty-four dogs were included in the study on the basis of completeness of medical records. All dogs underwent exploratory laparotomy, and dogs were allotted to 4 groups according to primary site of tumor: spleen (16 dogs, median age 10.3 years), stomach/small intestine (13 dogs, median age 10.3 years), cecum (10 dogs, median age 11.8 years), and liver (5 dogs, median age 9 years). All dogs with leiomyosarcoma of the liver had visible metastasis and were euthanatized at surgery. In the other 3 groups, 79% of the dogs had no gross evidence of metastasis at surgery, and 64% survived greater than 2 weeks. Median survival in these 3 groups was 10 months (range, 1 month to 7 years); 48% died of metastasis, 32% died of unrelated causes, and 16% died of unknown causes. The prognosis in dogs with leiomyosarcoma of the spleen, stomach, small intestine, and especially the cecum is good to excellent if surgery is performed. In dogs with leiomyosarcoma of the liver, the prognosis is poor.


Orbital neoplasms in cats: 21 cases (1974-1990).

Squamous cell carcinoma was the most common neoplasm found in a review of case records of 21 cats with histopathologically confirmed orbital neoplasms. Other neoplasms found were lymphosarcoma, undifferentiated carcinoma, malignant melanoma, adenocarcinoma, fibrosarcoma, chondroma, and hemangiosarcoma. Three (14%) neoplasms were primary, 15 (71%) were secondary, invading the orbit from adjacent tissues, and 3 (14%) were a manifestation of multicentric disease. The most common clinical sign was exophthalmia, followed by chronic epiphora, enophthalmia, and strabismus. Mean survival time after diagnosis was 1.9 months. Ten cats were euthanatized at the time of diagnosis because of extensive disease. Mean survival time of the other 11 cats was 4.3 months. Skull radiography was helpful in diagnosing orbital neoplasms in 8 of 11 cats that had invasion of the orbit by adjacent neoplasms.


Femoral artery pseudoaneurysm in a monkey.

Pseudoaneurysm formation as a complication of routine blood collection was diagnosed in a monkey. Damage to the femoral artery resulted in hematoma formation with secondary organization, encapsulation, and vascular communication. Progressive lameness and muscular atrophy were the primary clinical signs. Surgical correction of the artery defect helped resolve the monkey's lameness and muscle atrophy.


Comparison of lidocaine, xylazine, and xylazine/lidocaine for caudal epidural analgesia in horses.

Caudal epidural analgesia was achieved in 6 adult horses on 3 successive occasions at weekly intervals by injection of lidocaine, xylazine, and a combination of lidocaine/xylazine through indwelling epidural catheters. Analgesia was defined as a lack of response to pinprick and hemostat pressure in the skin of the perineal area. A significant (P < 0.05) difference was not found for time of onset of analgesia between lidocaine (4.3 +/- 0.8 minutes, mean +/- SEM) and the lidocaine/xylazine combination (5.3 +/- 1.3 minutes). Time to onset of analgesia after administration of xylazine was significantly (P < 0.05) longer (32.0 +/- 3.4 minutes) than that for either of the other 2 treatments. Duration of analgesia was significantly (P < 0.05) longer for the combination (329.8 +/- 6.2 minutes) than for either drug used alone (lidocaine, 87.2 +/- 7.5 minutes; xylazine, 204.2 +/- 12.9 minutes). Pulse and respiratory rates were not significantly altered by any of the drugs. Neurologic sequelae were not clinically apparent after administration of the drugs or after chronic epidural catheterization.


Microvascular permeability changes in ischemia/reperfusion injury in the ascending colon of horses.

The normal microvascular permeability of the ascending colon in horses and the microvascular permeability of that segment after ischemia and reperfusion were investigated. Microvascular permeability was estimated by the ratio of lymphatic protein to plasma protein concentration (Cl/Cp) at high lymph flow rates in 8 adult horses in 2 equal groups: normal and ischemic (2-hour period). Lymphatic flow rates and lymph and plasma protein concentrations were determined. Intestinal biopsy specimens were obtained at the end of each experiment. Flow independent values were selected and compared by one-way ANOVA, and the mean and SEM of these values were determined. The mean Cl/Cp ratios for the flow independent part of each data set were as follows: normal = 0.36 +/- 0.08; ischemic = 0.70 +/- 0.08. These groups were significantly different (P < or = 0.0001). Microscopic evaluation revealed mild congestion and edema in the normal group. The ischemic group had mild to moderate mucosal degeneration, with moderate to severe congestion and edema. We concluded that ischemia of the ascending colon, when followed by reperfusion, results in a significant increase in microvascular permeability.


Effects of environment and management on mortality in preweaned dairy calves.

Forty-eight herds participating in the 1988/1989 Ohio National Animal Health Monitoring System dairy project were monitored for 1 year to determine the effects of environment and management on mortality in preweaned calves. Environmental factors were evaluated by veterinarians during monthly visits to the herds. Management procedures were measured through the use of a questionnaire administered near the end of the project. Mortality in preweaned calves was calculated for each herd by using data from project records on calf mortality and animal inventory, which were collected monthly by veterinarians. Relationships between the management/environment variables and calf mortality were examined by use of analysis of covariance. Herd size, days on a nipple feeder, navel disinfection, type of housing, and whether each calf observed with diarrhea was treated with antibiotics were the variables that had an impact on herd mortality. These variables explained approximately 39% of the variation in mortality among herds.


Effect of concentration and source of sulfate on nursery pig performance and health.

The effect of sulfate in drinking water at concentrations of 600, 1,200, and 1,800 mg/L on nursery pig performance and health was evaluated over 28 days on 415 weaned pigs. Sodium sulfate and magnesium sulfate were evaluated in combination at concentrations of 600, 1,200, and 1,800 mg/L, and independently at concentrations of 600 and 1,800 mg/L in the drinking water. Seven treatment groups and 1 control group were evaluated for mean gain, feed consumption, water consumption, feed conversion, prevalence of diarrhea, and evidence of common post-weaning enteric pathogens. Statistical analysis was performed, using analysis of variance with repeated measures including initial pig weight as a covariate. Prevalence of diarrhea was analyzed nonparametrically with a repeated measures design. Results indicated that pigs drinking 600, 1,200, or 1,800 mg of sulfate/L water had increased prevalence of nonpathogenic diarrhea during the trial period. There was a trend for increased water consumption corresponding to increased sulfate in the water. Differences in mean daily gain, feed consumption, or feed-to-gain ratios were not observed. Forty-five pigs were treated at least once during the trial and 4 pigs died, resulting in a nursery morbidity of 11% and mortality of 0.96%. Fourteen isolates of enterotoxigenic Escherichia coli were found and rotavirus was isolated from 1 pig. Pigs in this study were not exposed to transmissible gastroenteritis virus. Except for an increase in fecal moisture content (not associated with pathogenic diarrhea), concentrations of up to 1,800 mg of sodium, magnesium, or a combination of sodium and magnesium sulfate/L had no adverse effect on nursery pig performance.


Postanesthetic recumbency associated with hyperkalemic periodic paralysis in a quarter horse.

Anesthesia and surgery in a Quarter Horse affected with hyperkalemic periodic paralysis resulted in euthanasia after 7 days of postoperative recumbency. Initial recovery was uneventful after extensive sinus surgery, but within 2 hours, the horse had severe muscle weakness. Plasma electrolyte concentrations were within the normal range during the period of recumbency. There was no clinical or laboratory evidence of severe muscle damage. Despite treatment with acetazolamide, isoproterenol, and intensive nursing, the horse was unable to stand for more than a few seconds and developed severe decubital ulcers. Ultrastructural examination revealed nemaline rods and swollen mitochondria in disrupted myofibers.


Bilateral ureterocystostomy in a 450-kg horse with ectopic ureters.

A 450-kg yearling Clydesdale filly was determined to have bilateral ectopic ureters. The resulting incontinence caused severe malodorous perineal dermatitis. Bladder capacity was measured at 800 ml. The urethral sphincter lacked tone, and the horse was seen to urinate in a normal manner only 2 or 3 times a week. A midline celiotomy was performed, and the ureters were identified by cannulation from the ectopic openings. The ureters were ligated, and the cut ends were anastomosed to the dorsal bladder surface by an extravesicular end-to-side technique. A partial thickness seromuscular layer of the bladder was sutured over the ureters in a cranial direction from the anastomosis site for 15 mm. This fixed the ureters to the dorsal surface of the bladder and protected the anastomosis site from tension. After surgery, the horse urinated n a normal manner many times a day. Urinary incontinence continued, but gradually improved. Bladder capacity increased over 13 months to 4.3 L. Surgical (urethral extension) and medical (phenylpropanolamine and estrogen) treatments were instigated to increase urethral sphincter tone. Urinary incontinence continued to improve and, at 11 months after surgery, incontinence was negligible, and the perineal dermatitis had healed.


Arthroscopic removal of a palmar radial osteochondroma causing carpal canal syndrome in a horse.

A 5-year-old Arabian stallion with moderate effusion in the right carpal canal and intermittent lameness in this limb was diagnosed to have an osteochondroma projecting from the distal portion of the radius into the carpal canal. oral phenylbutazone treatment over the next 3 years allowed the stallion to continue its show career. Right forelimb lameness returned at that time, and ultrasonography revealed the osteochondroma impinging on the dorsal surface of the deep digital flexor tendon. The owner elected to have the osteochondroma surgically removed. The horse was anesthetized, and the carpal sheath was distended with balanced polyionic solution. A 4-mm arthroscope was inserted into the carpal sheath, and the osteochondroma projecting into the sheath was identified. The osteochondroma was removed by use of a Ferris-Smith bone rongeur, which was inserted into the carpal sheath through a stab incision over the osteochondroma. The effusion in the carpal sheath and the lameness resolved by 2 months, and the horse was returned to training 4 months after surgery.


Primary meningeal lymphoma in a horse.

Primary meningeal lymphoma was diagnosed in an 18-year-old Morgan gelding. The horse was examined because of a 3-day history of progressive ataxia and weakness. The gait abnormalities were worse on the left side, and the pelvic limbs were more affected than the thoracic limbs. Additional findings included signs of depression, miosis of the left pupil, ptosis of the left upper eyelid, and areas of muscle atrophy on the left side of the neck and over the dorsal aspect of the left scapula. Inflammatory changes were evident in the CSF. At necropsy, there was diffuse and irregular thickening of the dura mater along the entire spinal cord. Histologic examination revealed infiltration of the leptomeninges with neoplastic lymphocytes.


Cervical fibrotic stenosis in a young Rottweiler.

An 18-month-old neutered male Rottweiler was examined because of slowly progressive spastic tetraparesis and ataxia. Signalment and clinical signs were suggestive of 2 neuronal degenerative diseases presumed to be inherited in young Rottweilers: leukoencephalomyelopathy and neuroaxonal dystrophy. Myelography revealed an extradural compression at the articulation of the second and third cervical vertebrae. At surgery, focal hypertrophy of the yellow ligament was observed to compress the spinal cord ventrally at that site.


Acquired syringomyelia in a dog.

Acquired syringomyelia was diagnosed in an 11-year-old Fox Terrier with progressive paresis in the left pelvic limb. Myelography and magnetic resonance imaging confirmed an intramedullary lesion involving the left dorsolateral portion of the spinal cord at the level of L-2 and L-3 vertebrae. Clinical signs improved after surgical syringotomy. Microscopic evaluation of a biopsy specimen from the cyst wall did not establish a definitive histologic diagnosis. The cyst was decreased in size on magnetic resonance imaging 7 months later.


Ocular manifestation of systemic histiocytosis in a dog.

A 3-year-old sexually intact female Bernese Mountain Dog was referred for treatment of a descemetocele of the left eye. Physical examination revealed bilateral exophthalmos and scleral thickening, multiple cutaneous nodules, and mandibular paralysis in addition to ulcerative keratitis associated with a Pseudomonas infection. One year prior to examination, a biopsy specimen of the episcleral tissue from the right eye had been interpreted as nodular granulomatous episclerokeratitis (fibrous histiocytoma). Immunosuppressive treatment prior to referral had not resulted in remission of the ocular lesions. When we examined the biopsy specimen, we interpreted the lesions to represent episcleral involvement of systemic histiocytosis. Because of the poor prognosis, the dog was euthanatized.


Monoclonal gammopathy in a dog with plasmacytic gastroenterocolitis.

Monoclonal gammopathy associated with plasmacytic gastroenterocolitis was diagnosed in a dog. Treatment consisted of immunosuppressive drugs and dietary manipulation. The gammopathy resolved. Fifteen months after initial diagnosis, the dog had a relapse of intestinal disease and recurrence of the gammopathy. After inducing a second remission, the gammopathy again resolved.


Ventricular arrhythmias in horses: 21 cases (1984-1989).

Ventricular premature depolarizations (VPD) were identified in 21 horses in which unexplained tachycardia or an arrhythmia was detected on auscultation. Horses were categorized into 3 groups on the basis of ECG findings. Seven horses had uniform isolated VPD (group 1); 7 horses had repetitive uniform VPD at a rate < 100 VPD/min (group 2); and 7 horses had either multiform VPD, R-on-T, or > or = 100 VPD/min (group 3). Concurrent systemic disease was identified in 12 horses, 7 of which had gastrointestinal tract disorders. Serum cardiac isoenzyme activities were high in 6 (2 from each group) of 13 horses in which they were measured. Serum electrolyte concentrations were normal in all but 1 of 11 horses in which they were measured. Antiarrhythmic drugs were given to 9 horses (all of which were in group 2 or group 3), 6 of which converted to sinus rhythm. Two horses that had R-on-T in the ECG died shortly after initiation of antiarrhythmic treatment. An accelerated idioventricular rhythm persisted in 1 horse for at least 8 months and failed to respond to antiarrhythmic drugs. Ventricular premature depolarizations resolved or decreased considerably in frequency in 11 horses without the administration of antiarrhythmic agents. Treatment in these horses included therapy for any underlying systemic disease, corticosteroids, nonsteroidal antiinflammatory drugs, or stall rest. The remaining horse was euthanatized several hours after hospitalization. Five horses died or were euthanatized either during hospitalization or several months after being discharged. Myocardial lesions were identified at necropsy in 2 horses.


Ionized calcium concentration in horses with surgically managed gastrointestinal disease: 147 cases (1988-1990).

Packed cell volume, total plasma protein, serum sodium, potassium, and ionized Ca2+ concentrations, and blood pH were determined at the time of admission and following surgery in 147 horses with acute abdominal crisis. Horses were allotted to 3 categories on the basis of the surgical lesion: (1) nonstrangulating obstruction of the ascending or descending colon (category A, n = 76), (2) strangulating and nonstrangulating infarction of the cecum or ascending colon (category B, n = 37), and (3) strangulating and nonstrangulating infarction of the small intestine (category C, n = 25). Horses with low serum ionized Ca2+ concentration following surgery were given 23% calcium gluconate (100 to 300 ml) IV to effect, and ionized Ca2+ concentration was determined following treatment. The serum ionized Ca2+ concentrations of horses in categories A, B, and C before and after surgery were lower than our normal laboratory reference range. Prior to surgery, serum ionized Ca2+ concentration measured from horses in category B and C was lower than that in horses in category A. There was no difference in ionized Ca2+ concentration in serum samples obtained before surgery in horses from category B and C, and in serum samples obtained following surgery. There was a decrease in ionized Ca2+ concentration during surgery in horses in category A. There was no change between preoperative and postoperative ionized Ca2+ concentration in the samples obtained from horses in category B and C. After calcium gluconate administration, all horses with low serum ionized Ca2+ after surgery had concentrations within our normal range. Measurement of serum ionized Ca2+ in horses with an acute abdominal crisis is recommended.(ABSTRACT TRUNCATED AT 250 WORDS)


Pedunculated lipomas as a cause of intestinal obstruction in horses: 17 cases (1983-1990).

The medical records of 17 horses that were evaluated and treated because of colic caused by pedunculated lipomas between 1983 and 1990 were reviewed. The mean age of the horses was 16.6 +/- 3.9 years (range, 10 to 26 years), which was significantly greater than that of the population of horses evaluated because of colic (control population) during the same period. There were significantly more geldings (76.5%), compared with the control population. Nasogastric reflux ranged from 1 to 16 L in 8 horses and was not obtained in 9 horses. Abdominal palpation per rectum revealed small intestinal distention in 13 horses, displaced large colon in 7 horses, and large colon impaction in 2 horses. Peritoneal fluid was abnormal in 11 of 12 horses from which it was obtained successfully. One horse was euthanatized after unsuccessful medical treatment. Surgery was performed in 16 horses. Lipomas were blindly resected in 5 horses or exteriorized and resected in 6 horses. The method used to resect the lipoma was not recorded in 5 horses. The ileum and/or jejunum was strangulated in 15 horses, the small colon was strangulated in 1 horse, and the jejunum was obstructed in 1 horse. The length of intestine resected ranged from 0.15 to 7.2 m. Fourteen horses survived surgery, of which 11 were discharged from the hospital (short-term survival rate of 78.6%). Excluding 2 horses lost to follow-up evaluation, 6 of 12 horses that survived surgery were alive 2 to 56 months following surgery (long-term survival rate of 50%), and 9 of 15 horses died or were euthanatized (fatality rate of 60%).


Diskospondylitis associated with Brucella canis infection in dogs: 14 cases (1980-1991).

A retrospective study of 135 dogs with diskospondylitis revealed 14 dogs with concurrent Brucella canis infection. Sexually intact male dogs and dogs in the southeastern United States appeared to be at higher risk. Results of bacteriologic culturing of blood were less likely to be positive for dogs with diskospondylitis caused by B canis infection than for dogs with diskospondylitis caused by other organisms. Follow-up evaluation of 13 of the 14 dogs revealed complete remission of clinical signs in nine, but serologic test results continued to be positive for B canis infection long after resolution of clinical abnormalities. Radiographic follow-up evaluation in 6 dogs revealed active lesions despite complete remission of clinical abnormalities.


Lymphoma involving large granular lymphocytes in cats: 11 cases (1982-1991).

Medical records of 11 cats with lymphoma involving large granular lymphocytes were reviewed. All 9 cats tested were FeLV-negative. Ten cats had a history of anorexia, lethargy, vomiting, or diarrhea, and had lymphoma involving abdominal viscera. The most common site of tumor in these cats was the jejunum. One cat had cutaneous masses caused by dermal and epidermal infiltration with neoplastic large granular lymphocytes. The most common hematologic abnormality was leukocytosis, characterized by neutrophilia with a left shift (7 cats); 2 cats had a left shift without neutrophilia. None of the cats had lymphocytosis, but immature large granular lymphocytes were found in the blood of 4 cats. The most common serum biochemical abnormalities were hypoalbuminemia (10 cats), hypocalcemia (10 cats), hypoproteinemia (9 cats), high aspartate transaminase activity (9 cats), and hyperbilirubinemia (8 cats). Large granular lymphocytes were characterized by abundant cytoplasm containing distinct azurophilic granules that varied in size and number. The most common cytochemical staining pattern included detection of alpha-naphthyl butyrate esterase, acid phosphatase, and beta-glucuronidase activities. On examination of histologic sections, granules stained weakly eosinophilic with Giemsa and moderately with periodic acid-Schiff reaction. Ultrastructurally, the granules appeared membrane bound and contained an electron-dense matrix in 4 cats.


Actions of isoflurane and halothane in pregnant mares.

Eighteen healthy, pregnant mares scheduled for laparotomy and uterine manipulation were randomly allotted to 2 equal groups. After IV administration of xylazine hydrochloride and thiamylal sodium, general anesthesia was maintained with halothane (HALO) or isoflurane (ISO) in oxygen. Results of cardiovascular measurements were similar with both inhalant anesthetics; mean arterial blood pressure was 79 and 82 mm of Hg with HALO and ISO, respectively. Respiratory rate decreased most with ISO (mean frequency was 4 and 9 breaths/min with ISO and HALO, respectively). Partial pressure of arterial CO2 was increased similarly with HALO and ISO. Partial pressure of arterial O2 varied greatly among mares and decreased with duration of use of both anesthetics. Recovery time from anesthesia was significantly (P < 0.05) shorter after use of ISO vs HALO. Minor superficial injuries were associated with recovery from both anesthetics (in 5 mares with ISO and in 1 mare with HALO). Physical signs of postanesthetic myopathy or vital-organ dysfunction were not associated with either agent.


In vitro susceptibility to antimycotics of Microsporum canis isolates from cats.

One hundred thirty-four isolates of Microsporum canis, obtained from cats, were tested for in vitro susceptibility to various antifungal agents. The fungi were classified as susceptible, resistant, and intermediate by measuring the size of the zone of inhibited growth on yeast nitrogen base agar medium. Clotrimazole had the highest activity (99.2%), followed by tioconazole (89.6%), griseofulvin (88.8%), econazole (73.1%), ketoconazole (50.7%), miconazole (15.7%), and isoconazole (12.7%). We found 14.9% of the isolates to be susceptible to all the assayed drugs, whereas the highest resistance frequency (41.8%) was against 2 antimycotics. A simultaneous resistance to all the tested antimycotics was not found. The differences among the antifungal drugs activity were examined, and administration of drugs for which a simultaneous resistance was minimal is suggested.


Milk antimicrobial drug residue assay results in cattle with experimental, endotoxin-induced mastitis.

Antimicrobial drug residue testing was performed on milk samples obtained from 8 cows with experimental endotoxin-induced mastitis, using 4 commercially available assay kits. Although none of the cows in the study received antimicrobials, only 1 of the 4 assay procedures, assay C, had consistently negative results (specificity = 1.00). The proportion of positive assay results varied from 0 to 1.00 among combinations of sampling time, sample status (endotoxin-infused quarter vs composite noninfused sample). The proportion of positive results found when assay C was used (0) differed significantly from the proportion found when the 3 other assays were used. The proportion of positive results did not differ significantly between assay A (0.45) and assay B (0.48); however, both assays had a significantly lower proportion of positive assays than did assay D (0.86). Logistic regression models were developed predicting positive milk antimicrobial drug residue assay results as a function of assay kit, sample status, and time interval following experimental challenge exposure. Using assay A as a baseline risk, assay B and assay D were more likely to have positive assay results, and assay C had a decreased risk of positive assay results. Milk samples from endotoxin-infused quarters were at increased risk for positive assay results, compared with noninfused composite samples. Samples collected from endotoxin-infused quarters or control quarters were at increased risk for positive assay results following the intramammary infusion of endotoxin. Our findings suggest that specificity of milk antimicrobial drug residue assays varies greatly among assay kits and that intramammary inflammation may increase the proportion of false-positive assay results.


Efficacy of milbemycin oxime against experimentally induced Ancylostoma caninum and Uncinaria stenocephala infections in dogs.

Twenty-eight helminth-naive Beagles, 16 to 26 weeks old, were inoculated with 200 third-stage larvae each of Ancylostoma caninum and Uncinaria stenocephala 5 times at weekly intervals. Dogs were randomly allocated to 4 groups of 7 on the basis of fecal egg counts, and treatments were randomly assigned. Groups 1 and 3 were given milbemycin oxime at a dosage of 500 micrograms/kg of body weight, PO, on day 0 and on days 0 and 30, respectively; groups 2 and 4 were nontreated controls. Fecal egg counts were evaluated before and after treatments. Feces were collected daily for 7 days after the final treatment for recovery of worms passed, and all dogs were euthanatized 7 days after the final treatment for recovery of worms retained. A 65.7% reduction from the pretreatment value for geometric mean hookworm egg count was found 7 days after the first treatment, and a 97.1% reduction 7 days after the second treatment. Although milbemycin oxime had 96.5% and 99.5% controlled efficacy against A caninum after 1 or 2 treatments, respectively, it lacked efficacy against U stenocephala. The geometric mean number of U stenocephala and the total number of hookworms retained after 1 or 2 treatments were not significantly different from the numbers retained by the corresponding control groups.


Renal dysfunction associated with infection of Leptospira interrogans in a horse.

Renal failure associated with infection of Leptospira interrogans was detected in a horse. Fever, leukocytosis, pyuria, isosthenuria, and azotemia were suggestive of an inflammatory urinary tract disease. Despite persistent pyuria, no bacteria were found during routine microscopic examinations or bacteriologic culturing of urine. A fluorescent antibody examination of the urine was positive for L interrogans. Serologic testing during a 6-month period, supported an acute infection with L interrogans serovar pomona. Treatment with intravenously administered fluids and antimicrobials resulted in clinical recovery. Leptospira interrogans serovar pomona has been reported as causing fever, uveitis, or abortion in horses.


Epiglottic augmentation by use of polytetrafluoroethylene to correct dorsal displacement of the soft palate in a standardbred horse.

A 2-year-old 400-kg Standardbred colt with a history of exercise intolerance was determined to have dorsal displacement of the soft palate (DDSP). Standing endoscopy revealed a soft, flaccid, and hypoplastic epiglottis and arytenoid cartilages that moved symmetrically and abducted fully. Lateral laryngeal radiography was used to calculate a corrected thyroepiglottic length of 6.48 cm. Videoendoscopy during exercise on a high-speed treadmill at standardized treadmill speeds was performed weekly for 3 consecutive weeks. The soft palate dorsally displaced at each examination. A sternohyoideus/sternothyroideus myectomy was followed by 2 weeks of stall rest and 2 weeks of treadmill training. Because endoscopy during exercise at standardized treadmill speeds caused the horse to dorsally displace the soft palate once a week for 3 weeks after the myectomy, this surgery was deemed ineffective in this horse. Epiglottic augmentation was performed by injecting 7 ml of polytetrafluoroethylene into the ventral submucosal space of the epiglottis. After 21 days of stall rest and 5 weeks of pasture rest, the horse was placed on a 2-month treadmill conditioning program. Using endoscopy at standardized treadmill speeds, exercise efforts to encourage DDSP were unsuccessful, which suggested that epiglottic augmentation by use of polytetrafluoroethylene was an effective surgical treatment to correct dorsal displacement of the soft palate in this horse. It is believed that polytetrafluoroethylene increases the rigidity of the epiglottis, allowing it to maintain the ventral position of the soft palate.


Selective IgM deficiency and abnormal B-cell response in a foal.

Selective IgM deficiency was diagnosed in a 3-month-old Standardbred colt that was referred for chronic respiratory tract disease. Immunoglobulin quantification revealed normal IgG and IgA concentrations, but undetectable IgM concentration. Stimulation of blood lymphocytes with the T-cell mitogens concanavalin A and phytohemagglutinin yielded results within the normal range. However, stimulation with the B-cell mitogen lipopolysaccharide produced no response. A B-cell defect similar to that associated with several immunodeficiency disorders in people was suggested as the cause of the IgM deficiency in this colt.


Penicillin-induced immune-mediated hemolytic anemia in a horse.

A 5-year-old female American Quarter Horse was determined to have immune-mediated hemolytic anemia after detection of a positive response to a direct Coombs' test. Penicillin-induced immune-mediated hemolytic anemia was confirmed via a direct antiglobulin test, using penicillin-coated RBC. The horse was clinically improved and the anemia resolved in response to supportive care and discontinuation of penicillin treatment. Penicillin should be considered a possible cause of immune-mediated hemolytic anemia in horses.


Mycoplasma mycoides subspecies mycoides as the cause of a subauricular abscess and mastitis in a goat.

A 6-year-old female goat was admitted with right-sided subauricular swelling and facial nerve paralysis. Mastitis developed subsequently. The subauricular swelling localized to a mass and was excised. Mycoplasma mycoides subsp mycoides was cultured from samples obtained from the mass and mammary gland. After clinical improvement, the goat was discharged to the owner with instructions to isolate the goat and to submit milk samples from the rest of the herd for microbial culturing. Mycoplasma spp can spread to other tissues from an initial site of infection. In goats with clinical signs similar to those of the goat of this report, samples should be obtained for microbial culture on Mycoplasma medium. Goats infected with Mycoplasma spp should be isolated or culled because of the risk of transmission to uninfected animals.


Methemoglobinemia induced by a benzocaine-based topically administered anesthetic in eight sheep.

Benzocaine-based anesthetic sprays are commonly used in sheep to anesthetize the nasal passages and glottis before intubation. Sprays containing benzocaine have been identified as causing methemoglobinemia in dogs, cats, and human beings. Diagnosis of benzocaine-induced methemoglobinemia was made in 8 Dorset-Finn ewes exposed to a 2-second burst of (approx 56 to 112 mg of benzocaine) anesthetic spray. Venous blood samples taken 10 to 20 minutes after intranasal application of the spray revealed methemoglobinemia of 22.6 +/- 1.8% (mean +/- SD) in 9 samples from 8 ewes. Four other ewes intentionally exposed did not have methemoglobinemia. Topical use of benzocaine-containing anesthetics in sheep is not recommended. The high methemoglobin concentration induced by this product may substantially alter the cardiovascular and pulmonary function, blood gas analyses, and exercise capacity, thereby compromising animal health and/or research results. Although it appears that minimal clinical signs are induced in healthy animals, the risks of compromising a subclinically ill animal do not offset the benefits of this product.


Hemangiosarcoma of the external naris in a cow.

A tumor was removed from the nose of a 4-year-old Holstein. Hemangiosarcoma was diagnosed on histologic examination. Redevelopment of the tumor necessitated a second surgery. Routine CBC and serum biochemical analysis were normal. Clinical signs of metastasis were not reported by the owner during the next 13 months before the cow was sold for slaughter.


Aneurysmal bone cyst in a Holstein bull.

A 3-year-old Holstein bull was examined because of a mass involving the cranial portion of the right hemimandible and the oral cavity. The mass had been observed 2 weeks earlier. The bull had lost weight throughout the 45 days before admission, and was anorectic at the time of admission. An aneurysmal bone cyst of the mandible was diagnosed.


Penile hematoma in bulls: 60 cases (1979-1990).

Sixty bulls with penile hematomas were examined from 1979 through 1990. Thirty-eight bulls underwent surgical correction, 17 bulls were managed by medical treatment, and 5 bulls were not treated. Hereford and Polled Hereford breeds represented the majority (n = 37, 62%) of the bulls, with 10 other breeds representing the remainder (n = 21, 35%) in this study; breed was not reported in 2 bulls. Follow-up information was obtained from owners (40/60) through conversation on the success or failure of treatment, interval of sexual rest, duration of breeding soundness, and final outcome of the bull. Surgical correction was successful in 19 (70%) of 27 cases; medical treatment was successful in 6 (46%) of 13 cases. Of the 8 bulls that had penile hematomas with swelling measuring > 20 cm in width, 6 were successfully treated surgically, compared with 1 of 3 successfully treated medically. Of the bulls with penile hematomas having a swelling measuring < or = 20 cm in width, 7 of 9 were successfully treated surgically, compared with 4 of 5 successfully treated medically. Duration of the penile hematoma had little effect on the success of surgical correction. Of the bulls allowed sexual rest for > 2 months after treatment was initiated, 6 (25%) of 24 had a recurrence of penile hematoma. Four (40%) of 10 bulls allowed sexual rest for < or = 2 months had a recurrence of penile hematoma.


Gram-negative bacterial infection in neonatal New World camelids: six cases (1985-1991).

Gram-negative bacterial infections were documented in 6 neonatal New World camelids (5 Ilamas and 1 alpaca). The organisms isolated from blood before death or from multiple organs after death were Escherichia coli (n = 3), Actinobacillus sp (n = 1), and Klebsiella pneumoniae (n = 1). Only 2 crias survived, and 1 became blind secondary to retinal detachment and ocular inflammation, which developed after treatment for bacterial infection. Abnormal events during the perinatal period (prematurity, dystocia, cesarean section, weak at birth) were reported in all 6 crias. Signs of depression, convulsions, and/or coma were observed in all animals. Diarrhea and respiratory distress were also noticed in the 3 crias that died shortly after admission. Serum immunoglobulins were assessed, but without the benefit of a stall-side test specific for Ilama immunoglobulins. All crias were suspected to have poor transfer of maternal immunoglobulins. Hemograms and serum biochemical values prior to the initiation of treatment were obtained on 5 of the 6 crias. Total nucleated cells ranged from 1,400 to 23,100 cells/microliter. Four of the 5 crias has a left shift, and 2 crias had toxic neutrophils. Serum glucose concentrations, measured in 5 of 6 crias, ranged from 83 to 293 mg/dl. Serum creatinine values were high in 2 of 5 crias, 1 of which had acute tubular necrosis. Three crias with high serum electrolyte (sodium, chloride, or potassium) values subsequently died. Arterial blood gas values were assessed in 3 crias, 1 of which had respiratory alkalosis and mild hypoxemia.


Evaluation of rhinoscopy and rhinoscopy-assisted mucosal biopsy in diagnosis of nasal disease in dogs: 119 cases (1985-1989).

The case records of 149 dogs examined from 1985 to 1989 with clinical signs of nasal disease were reviewed. Gross rhinoscopy was performed in 119 dogs, and rhinoscopy-assisted pinch biopsy was performed in 109. Rhinoscopy was performed by use of a 2.7-mm rigid fiberoptic endoscope. Mucosal biopsy specimens were obtained with rhinoscopic guidance by use of a 2 x 3-mm biopsy forcep. Gross, cytologic, and histologic findings are summarized. Ninety-four of 119 cases could be evaluated on the basis of diagnostic and follow-up criteria established by the authors. The diagnostic success rate of gross rhinoscopy with rhinoscopy-assisted biopsy was 83% (78 of 94 evaluated cases). Protracted hemorrhage was a complication in 2 of 109 cases in which rhinoscopy-assisted biopsy was performed. It was concluded that rhinoscopy with rhinoscopy-assisted biopsy contributes important diagnostic information in dogs with nasal disease without the relative invasiveness, expense, and risk of surgery.


Potentiation of the vincristine effect on P388 mouse leukemia cells by a newly synthesized dihydropyridine analogue, PAK-200.

A newly synthesized dihydropyridine analogue, 2-[benzyl(phenyl)amino]ethyl 1,4-dihydro-2,6-dimethyl-5-(5,5-dimethyl-2-oxo-1,3,2-dioxaphosphorina n-2-yl)-1- (2-morpholinoethyl)-4-(3-nitrophenyl)-3-pyridinecarboxylate (PAK-200), at 1 microM completely reversed the resistance to vincristine in vincristine-resistant P388 mouse leukemia cells (P388/VCR), in vitro. PAK-200 at 2 microM inhibited the efflux of [3H]vincristine from P388/VCR and increased the accumulation of [3H]vincristine in P388/VCR to a level similar to that in P388 cells. P-Glycoprotein in membrane vesicles from P388/VCR cells was photolabeled with [3H]azidopine. The labeling was completely inhibited by 10 microM PAK-200. The calcium antagonistic activity of PAK-200 was about 1000 times lower than that of another dihydropyridine analogue, nicardipine. Experiments with P388 and P388/VCR-bearing mice showed that PAK-200 enhanced the effect of vincristine on both leukemia cells in vivo. These results suggest that PAK-200 interacts with P-glycoprotein and reverses drug resistance in P388 mouse leukemia cells in vitro, and that PAK-200 has an ability to potentiate the effect of vincristine on P388 mouse leukemia cells in vivo.


Induction of adenocarcinomas in the glandular stomach of BALB/c mice treated with N-methyl-N-nitrosourea.

Male 6-week-old BALB/c strain animals (groups 1 and 2) received 10 weekly intragastric intubations of 0.5 mg/mouse of N-methyl-N-nitrosourea. At week 11 the forestomachs were resected in group 1 but not group 2. Although many animals in group 2 died due to development of squamous cell carcinomas in the forestomach, development of cancers in the glandular stomach was quite similar in both groups. Well-differentiated adenocarcinomas in groups 1 and 2 were found at low incidence at week 20, rising to 100% at week 40, with two lesions metastasizing to the lymph nodes. Four poorly differentiated adenocarcinomas and 5 signet ring cell carcinomas were also found in 27 glandular stomach tumor-bearing animals.


Detection of 2-amino-1-methyl-6-(4-hydroxyphenyl)imidazo[4,5-b]pyridine in broiled beef.

2-Amino-1-methyl-6-(4-hydroxyphenyl)imidazo[4,5-b]pyridine (4'-OH-PhIP) showed mutagenicity in Salmonella typhimurium TA98 in the presence of S9 mix, inducing 180 revertants per 100 micrograms. Since creatinine, tyrosine and glucose, which are present in meat, are expected to be involved in the formation of 4'-OH-PhIP, its presence in broiled beef was examined. 4'-OH-PhIP was detected in broiled beef by high-performance liquid chromatography and UV-spectrometry after extraction with 0.1 N HCl and purification by blue cotton treatment and ion exchange column chromatography. Its level was estimated to be 21.0 ng per g of broiled beef, which is comparable to that of 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP).


Simultaneous expression of T-cell and myeloid cell phenotypes in eight newly established HTLV-I-positive T-cell lines.

Eight cell lines were established from patients with adult T-cell leukemia, and from normal adults, by cocultivation with human T-cell leukemia virus type I(HTLV-I)-producer cell lines in the presence of interleukin-2. All of these cell lines harbored HTLV-I and showed T-cell markers CD2, CD3 and CD4, but not B-cell markers. Unexpectedly, all eight cell lines expressed a myeloid marker CD13 and three of the eight lines also expressed another myeloid marker CD33. Dual staining showed the simultaneous expression of CD3 and CD13 on the same cells. Thus, evidence was obtained for the expression of myeloid antigens on HTLV-I-harboring T cells.


Absence of ras family point mutations at codons 12, 13 and 61 in N-ethyl-N-hydroxyethylnitrosamine- or N-nitrosomorpholine-induced renal cell tumors in rats.

The prevalence of Ki-ras, Ha-ras and N-ras point mutation within exons 1 and 2 was studied in 17 cases of renal cell tumors (8 carcinomas and 9 adenomas) induced by N-ethyl-N-hydroxyethyl-nitrosamine or N-nitrosomorpholine. DNA samples prepared from acetone-fixed, paraffin-embedded tissues were amplified by means of the polymerase chain reaction, and point mutations at codons 12, 13 and 61 were analyzed by direct sequence methods with oligonucleotide primers. No mutations were detected in any of the renal tumors. The results thus indicated that ras family point mutation is not necessary for kidney tumor development in rats, supporting the view that ras mutations may not be generally relevant to neoplastic development in various organs in different species.


A case-control study of single and multiple stomach cancers in Saitama Prefecture, Japan.

A case-control study of stomach cancer was done in Saitama Prefecture, Japan, in relation to dietary, smoking, and drinking habits. The study was based on two sets of cases (216 male single and 35 male multiple stomach cancer cases newly diagnosed and of adenocarcinoma type), and 483 male controls derived from residents of Saitama Prefecture. Dietary habits were investigated for the intake of 12 separate foods and 12 food groups by means of a food frequency questionnaire, including individual taste preferences. Among the single stomach cancer series, dose-response relationships were observed for 7 dietary items (preference for salty foods, miso soup, boiled fish, pickled vegetables, nuts, raw vegetables, and seaweed) in the multiple logistic regression analysis. As for the multiple stomach cancer case series, dose-response relationships were observed for 3 dietary items (miso soup, fruits, and seaweed) in the multiple logistic regression analysis. Cigarette smoking and alcohol use were not significantly related to the risk of either single or multiple stomach cancer.


Anti-promoting effect of nordihydroguaiaretic acid on N-butyl-N-(4-hydroxybutyl)nitrosamine and sodium saccharin-induced rat urinary bladder carcinogenesis.

The effects of oral administration of nordihydroguaiaretic acid (NDGA), an antioxidant and inhibitor of arachidonic acid metabolism, on rat bladder carcinogenesis were examined. Six-week-old male Fischer 344 rats were given drinking water containing 0.05% N-butyl-N-(4-hydroxybutyl)nitrosamine for 4 weeks. Following this 4-week period, diet containing 5% sodium saccharin (SS) with or without 0.1% NDGA supplement was given to the rats for 36 weeks. The incidences of papillary or nodular (PN) hyperplasia and of papilloma in the group treated with SS plus NDGA were significantly lower than those in the group treated with SS alone. The number of PN hyperplasic foci per 10 cm of basement membrane in rats treated with SS plus NDGA was also lower than that in the group treated with SS alone. These results suggest that NDGA has an anti-tumor-promoting effect on rat bladder carcinogenesis.


Enhancing effects of harman and norharman on induction of preneoplastic and neoplastic kidney lesions in rats initiated with N-ethyl-N-hydroxyethylnitrosamine.

The modifying potential of two nephrotoxic agents, harman and norharman, on N-ethyl-N-hydroxyethylnitrosamine (EHEN)-induced renal and hepatic carcinogenesis was investigated in male F344/DuCrj rats. Animals were given 0.1% EHEN in their drinking water for the first 2 weeks as an initiator. Subsequently, starting 3 weeks from the commencement, they were fed diet containing these compounds at concentrations of 1000, 500 or 0 ppm until week 26, and then killed for light microscopic examination. The mean numbers of renal tubular cell hyperplasias/cm2 and those of tumors/cm2 in rats given harman and norharman at 1000 ppm after initiation, but not at 500 ppm, were significantly increased as compared to the control values. However, neither compound modified liver carcinogenesis. It is concluded that harman and norharman show enhancing effects on rat kidney carcinogenesis, when ingested at dose levels which cause renal tubular damage.


Synergism of environmental carcinogens and promoters on bladder cancer development initiated by N-butyl-N-(4-hydroxybutyl)nitrosamine in F344 rats.

Synergistic or additive effects of combined treatments with carcinogens or promoters on N-butyl-N-(4-hydroxybutyl)nitrosamine (BBN)-initiated rat bladder carcinogenesis were examined. Male F344 rats were given BBN as an initiator followed by low doses of 3 sodium salts (sodium bicarbonate, sodium L-ascorbate and sodium citrate) and/or 3 antioxidants (butylated hydroxyanisole, butylated hydroxytoluene and tertiary butylhydroxyquinone). Combined treatments with 3 sodium salts or 3 antioxidants, and especially all 6 chemicals together promoted bladder carcinogenesis. In addition, these combined treatments were associated with increased DNA synthesis of the bladder epithelium. Combined administration of the carcinogens, o-anisidine, p-cresidine, and 4-chloro-o-phenylenediamine at low doses also enhanced BBN-initiated bladder carcinogenesis. These results indicate that environmental carcinogens or promoters can exert synergistic or additive actions on bladder cancer induction.


Clonal origin of skin and bone tumors produced by repeated beta-irradiation in mosaic cell mice.

Clonal origin of skin and bone tumors produced by repeated beta-irradiation was determined by using mice with cellular mosaicism created by random X-chromosome inactivation, on the basis of phosphoglycerate kinase-1 (PGK). The backs of female C3H/He (Pgk-1a/Pgk-1b) mice were exposed to beta rays from 90Sr-90Y at a dose of 3 Gy per exposure 3 times weekly until tumors appeared. The cumulative tumor incidence reached 100% 500 days after the beginning of irradiation, as determined by the Kaplan-Meier method. All 8 tumors examined were of a single PGK phenotype: 5 squamous cell carcinomas and 2 osteosarcomas of A-type, and 1 squamous cell carcinoma of B-type. The absence of double PGK phenotype (AB-type) tumors indicated the monoclonal origin of the tumors produced by repeated irradiation.


Maternal transmission of HTLV-1 other than through breast milk: discrepancy between the polymerase chain reaction positivity of cord blood samples for HTLV-1 and the subsequent seropositivity of individuals.

We used a nested polymerase chain reaction (PCR) to diagnose HTLV-1 carriers. The DNA isolated from the nuclear extract obtained from frozen whole blood was found appropriate for PCR study both qualitatively and quantitatively. The use of freshly frozen whole blood made the field work much easier, and the use of a nuclear extraction procedure allowed DNA isolation in just 4 microcentrifuge tubes. We could not attain sufficient sensitivity to detect a single molecule with single-step PCR, but nested PCR was confirmed to detect a single molecule/reaction. All samples of the seropositive group including 94 blood donors, 66 mothers, and 13 children were positive in the nested PCR, while none of the seronegative group, including 198 blood donors and 285 children, was positive. Although 18/717 (2.5%) cord blood samples obtained from babies born to carrier mothers were PCR-positive, none of 5 formula-fed children tested who had been PCR-positive in the cord blood gave evidence of infection later on. Furthermore, all of 4 seropositive infected children who were formula-fed had been PCR-negative in their cord blood. The results are not consistent with intrauterine infection, but suggest the presence of a perinatal or postnatal infection route other than through breast milk.


High incidence of p53 gene mutation in human ovarian cancer and its association with nuclear accumulation of p53 protein and tumor DNA aneuploidy.

Using the polymerase chain reaction and single-strand conformation polymorphism analysis, p53 gene mutations were examined in 24 cases of ovarian tumor including 14 ovarian carcinomas and 2 borderline cases of common epithelial type, 7 germ cell tumors, and one stromal tumor. Abnormal bands indicating mutations were detected in 12 (50%) of the cases examined, being present most frequently in common "epithelial" ovarian carcinoma (71%, 10/14). One case each of squamous cell carcinoma originating in a dermoid cyst and anaplastic dysgerminoma were positive for mutation. Direct sequencing confirmed 12 mutations and revealed G-->A and G-->C nucleotide changes in 5 and 3 cases (42% and 25%), respectively. The mutation was localized at the CpG site of the gene in 3 cases. Immunohistochemical examination of p53 protein in 21 cases and DNA flow-cytometrical analysis in 17 cases were also performed. Nuclear accumulation of the p53 protein and DNA aneuploidy pattern were detected in 11 (52%) and 9 (53%) cases, respectively. These were significantly correlated with p53 gene mutation (P < 0.01 and P < 0.05, respectively; Fisher's exact test). Neither mutation of the p53 gene, nuclear accumulation of p53 protein nor DNA aneuploidy was detected in borderline cases of common "epithelial" type, typical dysgerminoma and immature teratoma. These results suggest that p53 gene mutation, nuclear accumulation of the protein and the DNA aneuploidy pattern are events occurring almost simultaneously in the progression of ovarian tumors, and that p53 abnormalities seem to be correlated with a high grade of malignancy.


Delayed DNA synthesis induced by 3-aminobenzamide in partially hepatectomized liver of rats.

The possibility of poly(ADP-ribosyl)ation playing a role during liver regeneration induced by partial hepatectomy (PH) in vivo was examined. When rats were given an i.p. injection of 3-aminobenzamide (ABA) at a dose of 600 mg/kg body weight 12 h after PH, the levels of DNA synthesis at 20 h after PH were significantly reduced. The time course of DNA synthesis in regenerating liver was significantly delayed in the ABA-treated group. Enzymatic assay revealed the activity of poly-(ADP-ribose)polymerase (PADPRP) in controls to be increased in parallel with the increase of DNA synthesis induced by PH. This increase in PADPRP activity was delayed and very much weaker after ABA treatment. The results thus suggested that poly(ADP-ribosyl)ation might play an important role in DNA synthesis during liver regeneration in vivo.


Tumor necrosis factor-alpha stimulates colony formation by a megakaryoblastic leukemia cell line, CMK.

The CMK cell line is an acute megakaryoblastic leukemia cell line established from a patient with Down's syndrome, and is known to possess characteristics of normal megakaryocytes. Several cytokines with the ability to stimulate megakaryopoiesis, such as interleukin-3 (IL-3), interleukin-6 (IL-6) and granulocyte-macrophage colony-stimulating factor (GM-CSF), stimulated colony formation by CMK cells. The present study revealed that tumor necrosis factor-alpha (TNF-alpha) stimulated colony formation by CMK cells; the potency was almost equal to that of IL-3, IL-6 or GM-CSF. Scatchard plot analysis revealed that CMK cells possess two types of specific binding sites for TNF-alpha. The high-affinity binding sites had an affinity constant of 0.18 nM, and numbered 5,000. The low-affinity binding sites had an affinity constant of 1.8 nM and numbered 19,000. These results raise the possibility that TNF-alpha can act as a growth-stimulating agent on megakaryocyte-lineage cell line.


Maintenance of androgen-, glucocorticoid- or estrogen-responsive growth in shionogi carcinoma 115 subline sustained in castrated mice with high dose of estrogen for 30 generations (3 years).

Shionogi carcinoma 115 (SC115), an androgen-dependent mouse mammary tumor, rapidly loses its androgen responsiveness after androgen withdrawal. The growth of this tumor can also be stimulated by high doses of estrogen or glucocorticoid. In the present study, the maintenance of hormone-responsive growth of SC115 tumors with a high dose of estrogen was examined in castrated male mice using an SC115 subline obtained by serial transplantations of SC115 tumors in estrogen-treated castrated mice for 3 years (30 generations) (subline E2). Seed tumors from both SC115 and subline E2 could rapidly grow in castrated mice given daily injections of testosterone propionate (TP), 17 beta-estradiol (E2), or dexamethasone (Dex) (100 micrograms/mouse/day) but not in those given vehicle alone. Although SC115 and subline-E2 tumors grown with TP or Dex showed temporary regression after steroid withdrawal, the tumors grown with E2 did not show such temporary regression. The TP-, E2-, or Dex-induced growth of subline-E2 tumors was almost the same as that of the original SC115 tumors. However, responsiveness to androgen, estrogen or glucocorticoid of both tumors disappeared within one passage in steroid-depleted castrated mice. The present findings demonstrate that the loss of responsiveness to androgen as well as to high doses of estrogen or glucocorticoid of SC115 tumors can be prevented in castrated mice not only with androgen but also with high doses of estrogen.


Some functions of the self personified by the father.

I have presented clinical material in order to illustrate a series of fantasies of parental intercourse which represent the self in successive stages of individuation from early projective identification to later introjective identification. From this is abstracted the idea of 'father' both as a component of the self representation and as the personification of the urge towards continuing development. Evidence is also gathered from the clinical material, supported by mythological parallels, to suggest that the whole process, including those components explicitly identified with the mother, is subsumed under an identification of the deintegrating self, its identity and integrity, with 'the father'.


The primary self and related concepts in Jung, Klein, and Isaacs.

In this paper, I have tried to re-examine my understanding of early psychic processes and contents. This has involved comparing and contrasting the ideas of Jung, Klein, Isaacs, and Fordham, with an emphasis on the contributions of Fordham. Fordham's postulate of a primary self that deintegrates and reintegrates is a model of the mind that combines structure and dynamics, and which, moreover, helps to describe what is observed in infant observations and infant research. Infant observation has been used to illustrate these concepts, and clinical material used to show how the same concepts can be used to describe impairments to psychic development. To pursue this study I have had to construct for myself models that describe and explain. I am aware that they are just as inaccurate as they might be accurate, because they imply that there is an answer to the questions I am asking, and that there is a way of describing and explaining what 'the answer' is. 'Nature is always too strong for principle', wrote Hume (Hume 1751, p. 121), and this is particularly true of the ultimately unknowable self.


Intimacies of the impersonal.

This paper is focused on the kinds of awareness that are exposed by clinical work conducted in the depth psychological tradition. The paper begins with an examination of Freud's clinical methodology, which is a description of a particular kind of attentiveness that reveals material normally obscured from conscious awareness. This type of awareness is thought to reveal the contents and the specific organizational features of the unconscious. In this paper, the organizational processes of the unconscious are interpreted to actually be the referents of a privileged type of perceptual awareness leading to a unique relationship to the immediate world. This is taken to be an assumption that is implicit in the models of psychotherapy authored by Jung and Reich. Both developmental and clinical researches are used to support this position. The differentiation between this awareness and the more traditional modes of awareness is further highlighted by an examination of the phenomenon of transference. Finally, a clinical example is presented to support the theoretical claims in the paper.


The andrology laboratory in an Assisted Reproductive Technologies program. Quality assurance and laboratory methodology.

Assuring the highest possible quality of care to the patient is the first goal of the andrology laboratory. Quality control and quality assurance as they apply to the andrology laboratory are outlined, and special problems in quality control for sperm function assays are addressed. An example of the patient review process is presented. Quality of care also depends on the ability of the laboratory to perform appropriate tests of sperm function that can diagnose sperm defects, predict success or failure of in vitro fertilization, and lead to rational therapies for sperm dysfunctions. Methods for, and diagnostic value of, sperm swim-out, enhanced sperm penetration assays, acrosome reaction assessment, motility analysis of capacitating sperm, and sperm-zona binding assays are reviewed. No single test, other than in vitro fertilization itself, is capable of providing a complete diagnosis or a highly accurate prediction. A battery of sperm function tests, arranged in an algorithm, is presented as a theoretically better approach.


Human Sertoli cells in vitro. Lactate, estradiol-17 beta and transferrin production.

Human Sertoli cell parameters, namely lactate, estradiol-17 beta, and transferrin production, were determined after a 24-hour incubation with either human follicle stimulating hormone (FSH) or dbcAMP in the presence or absence of testosterone plus a phosphodiesterase inhibitor (1-methyl-3-isobutylxanthine; MIX). Testicular tissues were obtained from 10 young patients (mean age, 29 years); using a 3-step enzymatic treatment, Sertoli cell enriched preparations (> 92%) were studied after 4 days as primary cultures. No significant changes in lactate, estradiol-17 beta, and transferrin outputs have been observed according to age in patients ranging in age from 16 years to 47 years. Sertoli cell production of the compounds is controlled by testosterone plus MIX; FSH (or dbcAMP) treatment only slightly improves their synthesis. It is suggested that human Sertoli cell function, as far as the parameters measured in this study are concerned, is likely regulated by cAMP-dependent and independent pathways.


Benastatins A and B, new inhibitors of glutathione S-transferase, produced by Streptomyces sp. MI384-DF12. I. Taxonomy, production, isolation, physico-chemical properties and biological activities.

Benastatins have been isolated as part of a program designed to find microorganism-produced inhibitors of glutathione S-transferase from Streptomyces sp. MI384-DF12. They were purified by chromatography of reversed-phase silica gel, silica gel and Capcell Pak C18 (HPLC) followed by solvent extraction and then isolated as yellow powders. Benastatins A and B have the molecular formulae, C30H28O7 and C30H30O7, respectively. They were competitive with 3,4-dichloronitrobenzene as the substrate, and the inhibition constants (Ki) of benastatins A and B were 5.0 x 10(-6) and 3.7 x 10(-6), respectively.


Benastatins A and B, new inhibitors of glutathione S-transferase, produced by Streptomyces sp. MI384-DF12. II. Structure determination of benastatins A and B.

Benastatins A and B, new inhibitors of glutathione S-transferase, have been isolated from the culture broth of Streptomyces sp. MI384-DF12. By X-ray crystallography, benastatin A was determined to be 8,13-dihydro-1,7,9,11-tetrahydroxy-13-dimethyl-8-oxo-3-pentyl- benzo[a]naphthacene-2-carboxylic acid. The structure of benastatin B was elucidated by NMR studies.


Initiation of sperm motility after mating in the rat and hamster.

Unlike those of many mammals, rat and hamster spermatozoa do not appear to be fully activated at ejaculation. Most rat spermatozoa transported en masse to the uterus approximately 2 minutes after coitus were vigorously motile on recovery soon thereafter in uterine fluid, whereas a majority, and sometimes all, were immotile in samples collected less than 2 minutes after coitus from the anterior vagina of normal females and up to 15 minutes after coitus from the anterior vagina in females with obstructed cervices. Many of these immotile rat vaginal spermatozoa began instant vigorous movement upon exposure to Tyrode's solution or uterine fluid. Hamster spermatozoa recovered from the vagina about 2 minutes after coitus were also immotile or displayed only slow, languid serpentine movements, but that motility profile remained very similar in spermatozoa taken 0.5 hours to 6 hours after coitus from the uterus, which is essentially fluid-free in the hamster. In the hamster, actively motile spermatozoa were evident only in the isthmus of the (transilluminated) oviduct. As in the rat, immotile vaginal and uterine hamster spermatozoa instantly began vigorous progressive motility in vitro on contact with Tyrode's solution or rat uterine fluid. Immotile spermatozoa from the rat and hamster cauda epididymidis immediately became highly motile in Tyrode's solution, and they developed a somewhat less rapid flagellar beat in 150 mmol/L NaCl or KCl, with or without 2 mmol/L CaCl2. In contrast, dilution with an isotonic sucrose solution containing no ions, or only 2 mmol/L CaCl2, evoked very slow and transient movement of rat and hamster epididymal sperm tails.(ABSTRACT TRUNCATED AT 250 WORDS)


Sperm motility under conditions of weightlessness.

The aim of this study was to determine the differences in motility of frozen and thawed bull spermatozoa under conditions of weightlessness compared with ground conditions. The tests were performed within a series of scientific and technologic experiments under microgravity using sounding rockets in the Technologische Experimente unter Schwerelosigkeit (TEXUS) program launched in Kiruna, North Sweden. Using a computerized sperm motility analyzer, significant differences were found in sperm motility under microgravity compared with sperm under gravitational conditions on earth. Computer analysis showed alterations in straight line and curvilinear velocity, as well as in linearity values. The amount of progressively motile spermatozoa, including all spermatozoa with a velocity > 20 microns/second, increased significantly from 24% +/- 9.5% in the reference test to 49% +/- 7.6% in the microgravity test. In conclusion, there is strong evidence that gravity influences sperm motility.


Nagstatin, a new inhibitor of N-acetyl-beta-D-glucosaminidase, produced by Streptomyces amakusaensis MG846-fF3. Taxonomy, production, isolation, physico-chemical properties and biological activities.

Nagstatin, a new inhibitor of N-acetyl-beta-D-glucosaminidase (NAG-ase) was discovered in the fermentation broth of Streptomyces amakusaensis MG846-fF3. It was purified by chromatography on Dowex 50W, Avicel and Sephadex LH-20 followed by the treatment of active carbon and then isolated as colorless powder. Nagstatin has the molecular formula of C12H17N3O6. It is competitive with the substrate, and the inhibition constant (Ki) was 1.7 x 10(-8) M.


Antioxidant enzyme activity in the maturing rat testis.

Developmental profiles of the activity of the antioxidant enzymes superoxide dismutase (SOD), catalase, glutathione peroxidase (GSH-Px), glutathione transferase (GSH-Tr), and hexose monophosphate shunt (HMS) were measured in the rat testis and liver. The level of SOD in the testis was high at the age of 6 to 10 days, after which it dropped to approximately one third of that level by 20 days of age, and remained there up to 8 months of age. In the liver, SOD activity steadily increased from the neonatal to adult stage of life, reaching the same level as detected in the testis. The testicular activity of catalase was only 2% to 7% of that found in liver at all ages. It increased in both organs up to 6 weeks of age, whereafter the hepatic activity gradually decreased and no further changes were seen in the testis. The GSH-Px activity was low in the testis and declined slightly with age, whereas activity in the liver increased four-fold between birth and adulthood. The activity of GSH-Tr was similar in both organs studied: it increased after birth, showing a maximum in the liver at 1.5 months (ten-fold increase) and in the testis at 5 months of age (four-fold increase). The HMS activity was two to three times higher in the liver than in the testis, and decreased slightly with age in both organs. Thus, the basal levels and developmental profiles of antioxidant enzymes in the testis differ greatly from those in the liver.(ABSTRACT TRUNCATED AT 250 WORDS)


Reveromycins, new inhibitors of eukaryotic cell growth. I. Producing organism, fermentation, isolation and physico-chemical properties.

New antibiotics named reveromycins A, B, C and D were isolated as inhibitors of mitogenic activity induced by epidermal growth factor (EGF) in a mouse epidermal keratinocyte. Reveromycins were produced by a soil actinomycete (strain SN-593) which belongs to the genus Streptomyces.


Pituitary-testicular axis in cardiomyopathic Syrian hamsters.

Testicular function and other endocrine parameters were studied in cardiomyopathic hamsters. In these animals, the major defect is an intracellular calcium overload, which is due to defective voltage-sensitive calcium channels. Basal circulating gonadotropin, prolactin, and triiodothyronine levels were lower in cardiomyopathic hamsters than in normal hamsters, but thyroxine, progesterone, and testosterone levels were not. In cardiomyopathic hamsters, the luteinizing hormone receptor (LHR) positive autoregulation by human chorionic gonadotropin (hCG) reached a maximum faster and at a lower dose than in normal hamsters. Similar results were observed for the response of circulating testosterone to hCG administration. The data indicate that, in spite of deficient pituitary function, cardiomyopathic hamsters have a normal or more efficient testicular function. This is probably the result of the cellular calcium overload, which would stimulate Leydig cell gene transcription, specifically that for LHR.


Reveromycins, new inhibitors of eukaryotic cell growth. II. Biological activities.

Reveromycins A, B, C and D showed inhibitory activity against EGF-stimulated mitogen response in Balb/MK cells. Furthermore reveromycins A, C and D exhibited morphological reversion of srcts-NRK cells, antiproliferative activity against human tumor cell lines and antifungal activity. The effects of reveromycins A, C and D on eukaryotic cells were closely similar to each other, but those of reveromycin B were very weak. In vitro studies revealed that reveromycin A is a selective inhibitor of protein synthesis in eukaryotic cells.


Reveromycins, new inhibitors of eukaryotic cell growth. III. Structures of reveromycins A, B, C and D.

Reveromycins A, B, C and D are new group inhibitors of the mitogenic activity of epidermal growth factor (EGF), produced by Streptomyces sp. Reveromycins are novel polyketide type antibiotics which have two terminal carboxylic groups, a spiroketal, a succinate and a varied side chain in the molecule. Determination of their structures by chemical and spectroscopic methods, in particular NMR studies, is described.


A new inhibitor of protein kinase C, RK-1409B (4'-demethylamino-4'-hydroxy-3'-epistaurosporine).

RK-1409B, a new inhibitor of protein kinase C, was isolated from the culture broth of Streptomyces platensis subsp. malvinus RK-1409. The structure was elucidated on the basis of spectroscopic analyses. RK-1409B inhibited protein kinase C in vitro and the morphological change of a human chronic leukemia cell line, K-562, induced by phorbol 12,13-dibutyrate with IC50 value of 0.4 microM.


Lactimidomycin, a new glutarimide group antibiotic. Production, isolation, structure and biological activity.

Streptomyces amphibiosporus R310-104 (ATCC 53964) produced a novel antibiotic lactimidomycin which showed inhibitory activity against fungi and prolonged the survival time of mice transplanted with experimental tumors. Structural studies clarified that lactimidomycin is a new glutarimide antibiotic having a unique unsaturated 12-membered lactone ring.


Butyrolactols A and B, new antifungal antibiotics. Taxonomy, isolation, physico-chemical properties, structure and biological activity.

New antifungal antibiotics, butyrolactols A and B, have been isolated from the culture broth of Streptomyces rochei S785-16. They are novel type of molecules containing a common 2,3-dihydroxybutyrolactone nucleus substituted with a different long hydroxyalkyl side chain. Butyrolactol A showed good antifungal activity against Aspergillus fumigatus and Trichophyton mentagrophytes, and moderately inhibited the growth of yeasts.


Antifungal cyclic peptides from the terrestrial blue-green alga Anabaena laxa. I. Isolation and biological properties.

Laxaphycins are responsible for the antifungal and cytotoxic activity of crude ethanolic extracts from the cultured blue-green alga Anabaena laxa. These cyclic peptides exhibit an unusual biological synergism when tested for antifungal or cytotoxic effects. The isolation procedure for the peptides, their characterization and biological activities are described here along with experiments demonstrating synergism between the two major laxaphycins.


Antifungal cyclic peptides from the terrestrial blue-green alga Anabaena laxa. II. Structures of laxaphycins A, B, D and E.

Laxaphycins A and B are the major components in an antifungal mixture of cyclic peptides from the terrestrial blue-green alga Anabaena laxa FK-1-2. NMR and MS spectral studies coupled with amino acid analysis indicate that the gross structures of laxaphycins A and B are cyclic (Aoc-Hse-E-Dhb-Hyp-Hse-Phe-Leu-Ile-Ile-Leu-Gly) where Aoc is a 3-aminooctanoic acid residue and cyclic (Ala-Hleu-Gln-N-MeIle-Hasn-Thr-Pro-Leu-Thr-Ade-Val- Hleu) where Ade is a 3-aminodecanoyl unit, respectively. Laxaphycin E, a minor cyclic undecapeptide, differs in gross structure from laxaphycin A in possessing a 3-aminodecanoic acid unit (Ade) in lieu of Aoc, whereas laxaphycin D, a minor cyclic dodecapeptide, differs from laxaphycin B in possessing a 3-aminooctanoyl unit (Aoc) instead of an Ade unit.


New antiviral antibiotics, cycloviracins B1 and B2. II. Structure determination.

The structures of novel antiviral antibiotics, cycloviracins B1 and B2 have been determined by means of chemical and spectroscopic methods including 2D NMR correlation spectroscopy. The antibiotics are unique macrocyclic diesters consisting of two D-glucoses, three 2-O-methyl-D-glucoses and two (C24 and C26) hydroxy fatty acids.


The distribution of DNA sequences hybridizing with antibiotic production and resistance gene probes within type strains and wild isolates of Streptomyces species.

Total DNA preparations from 74 antibiotic-producing type strains and 102 natural Streptomyces isolates were examined by dot blots for homology to 6 antibiotic production and resistance genes. Pattern diversity of hybridizations decreased as stringency increased from 65% to 85%. There were 146 unique profiles at 65% stringency with 13 repeated patterns, whilst there were only 14 unique and 11 repeated profiles at 85% stringency. Most of the strains which hybridized at 85% reacted with one or two probes although a few strains showed multiple homologies. This data was used to cluster strains and the groups defined were examined for phenotypic antibiotic resistance. Producers of certain classes of antibiotics clustered to specific groups and some gene homologies were more common amongst strains which produced similar antibiotics.


The squalestatins, novel inhibitors of squalene synthase produced by a species of Phoma. III. Biosynthesis.

The biosynthetic origin of the carbon and oxygen atoms of the novel fungal secondary metabolite 1 was studied. Incorporation studies with single and multiple labelled 13C precursors indicated that the major portion of the molecule was derived from two polyketide chains made up of acetate units. One of the chains had benzoic acid (which can be derived from phenylalanine) as a starter unit. The remaining carbons were derived from a four-carbon unit related to succinate and from methionine. Studies with [1-(13)C,18O2]acetate and 18O2 indicated that five of the oxygens, including both of the heterocyclic oxygens, were derived from atmospheric oxygen. The oxygens at the two ester carbonyls were derived from acetate.


Biosynthesis of thiopeptide antibiotic A10255: incorporation of isotopically-labeled precursors.

The biosynthetic origin of antibiotic A10255 was investigated using 14C- and 13C-labeled amino acids. DL-[1-(13)C]Serine labeled 15 of the 17 amino acid residues present in A10255G. These included the oxazole, thiazole, dehydroalanine, masked glycine, masked alanine and pyridine moieties. The same 15 residues labeled by serine were labeled by [2-(13)C]glycine, apparently by conversion of the glycine to [2,3-(13)C]serine. Formation of the pyridine ring occurred via a C3 to C3 condensation of two serines. The results indicated origin of the masked alanine from alanine; the masked glycine from glycine; the thiazole residues from cysteine; and the threonine, masked dehydrobutyrine, masked dehydronorvaline and masked dehydroleucine residues from threonine. L(-)[CH3-(13)C]Methionine labeled the methyl carbon of the masked dehydronorvaline moiety in factor B and the two methyl carbons of the masked dehydroleucine moiety in factor E. The results demonstrate that A10255 originates exclusively from amino acids in a manner similar to the closely related thiopeptide antibiotics nosiheptide and thiostrepton.


Synthesis and antifungal activities of pradimicin derivatives, modification at C4'-position.

The 4'-N-alkyl(1 approximately 10) and 4'-N-acyl derivatives (11 approximately 21) of pradimicins (PRMs) were synthesized by trimethylsilylation of PRMs A, C and FA-1 followed by condensation with appropriate alkylating and acylating agents. The 4'-hydroxy derivatives (23 and 24) were synthesized from PRM FA-2 in a 3-step sequence. Among these compounds, the 4'-N-carboxyl substituted alkyl (1, 5, 8 and 10), 4'-N-formyl (11) and 4'-axial-hydroxy (23) derivatives retained the antifungal activity of the parent compounds and showed great improvement in water solubility.


Role of the aminothiadiazolyl group in the antipseudomonal activity of cefclidin.

Cefclidin (E1040), which has an aminothiadiazolyl group in the 7 beta-side chain, showed about four-fold higher activity against Pseudomonas aeruginosa than its aminothiazolyl counterpart. Cefclidin had lower affinity and a higher Vmax value for the chromosomal type I beta-lactamase (cephalosporinase) from P. aeruginosa than its aminothiazolyl counterpart. No differences between the affinities of both compounds for the most of the sensitive essential PBPs were observed. Hydrophilicity of cefclidin was higher than that of its counterpart. The antipseudomonal activity of cefclidin, which was increased by the introduction of the aminothiadiazolyl group, was suggested to have resulted mainly from higher resistance to cephalosporinase hydrolysis at pharmacologically relevant low concentrations due to its low affinity for cephalosporinase, and secondarily from good penetration of cefclidin through the outer membrane due to increased hydrophilicity.


Studies on cephalosporin antibiotics. VI. Synthesis, antibacterial activity and oral efficacy in mice of new 7 beta-[(Z)-2-(2-aminothiazol-4-yl)-2-(hydroxyimino)-acetamido]-3- (substituted alkylthio)cephalosporins.

A series of new 7 beta-[(Z)-2-(2-aminothiazol-4-yl)-2-(hydroxyimino)acetamido] cephalosporins (1) having various substituted alkylthio groups at the C-3 position of the cephem nucleus were prepared and evaluated for antibacterial activity and oral absorption in rats. Of these, the cephalosporin with a cyanomethylthio group (1a) showed the greatest activity against Staphylococcus aureus and Gram-negative bacteria. Its pivaloyloxymethyl ester (6a), a representative prodrug, exhibited good in vivo efficacy in mice by oral administration. The structure-activity relationships of 1 are also presented.


Excitatory/inhibitory interaction in the LSO revealed by point process modeling.

We studied lateral superior olivary (LSO) unit responses to binaural tone-bursts using a general point process approach. We show that inhibition of the ipsilaterally elicited response by contralateral stimulation cannot be modeled simply as a reduction of the ipsilateral input. Statistical analyses reveal that inhibition operates by scaling the intensity of the point process describing the ipsilateral response. In some cases the scaling process has secondary effects: Binaurally elicited discharges produce bimodal interspike interval histograms from units that produce unimodal interval histograms under monaural stimulation. We present a specific point process model that describes the scaling process and successfully replicates the observed responses to monaural and binaural stimulation of the three types of LSO units: slow choppers, fast choppers, and bimodal units. We interpret scaling as a shunting inhibitory process in these LSO neurons. By relating scaling magnitude to interaural level difference, we demonstrate the spatial sensitivity of LSO units.


Glucuronic acid-containing glycosaminoglycans occur in otoconia: cytochemical evidence by hyaluronidase-gold labeling.

Localization of glucuronic acid-containing glycosaminoglycans in the gerbil utricle was examined, using a hyaluronidase-gold labeling technique with special emphasis on the otoconia. Otoconia and the gelatinous layer of the otoconial membrane were strongly labeled by hyaluronidase-gold. The secretory granules in supporting cells were also strongly labeled, suggesting that the organic matrix of otoconia is secreted from the supporting cells. Otoconia seem to lose labeling while they degenerated. The degenerating otoconia were observed to be absorbed into dark cells. Glucuronic acid-containing glycosaminoglycans occur in otoconia. These glycosaminoglycans may play a crucial role in the formation and degeneration of otoconia.


Preprotachykinin A mRNA detected by in situ hybridization in guinea pig vestibular ganglion.

In situ hybridization histochemistry was conducted to examine the expression of mRNA encoding preprotachykinin A (PPTA), the precursor of the neuropeptide substance P (SP) and neurokinin A (NKA), in guinea pig vestibular ganglion. Signals for PPTA mRNA moderately accumulated on most ganglion cells. SP and NKA are thus confirmed to be present in vestibular ganglion cells of the guinea pig.


A comparison of changes in the stereocilia between temporary and permanent hearing losses in acoustic trauma.

A comparison of stereociliary changes at different post-exposure intervals in ears with temporary and permanent hearing losses has been made. Twenty guinea pigs were exposed to either 110 dB SPL broadband white noise for 30 min (N = 10) or 120 dB SPL white noise for 150 min (N = 10). The recovery patterns for threshold shifts for both groups were systematically assessed at regular post-exposure intervals for 80 days, using the auditory cortex evoked response to tone bursts between 0.5 and 8kHz. Thirty-two animals that had been exposed to the same noise at either 110 dB for 30 min (N = 16) or 120 dB for 150 min (N = 16) were decapitated for scanning electron microscopic examination at the same post-exposure intervals. The threshold shifts induced by 110 dB noise were reversible while those induced by 120 dB were generally irreversible, although extreme variabilities existed among the animals. In the acute TTS ears, damage was confined to the third row of OHCs, where only the tips of the stereocilia were affected. Neither discontinuity of cuticular plate nor expelled cytoplasm was found in these cells. In the lesions of PTS, either all the three rows of OHCs or the IHCs and the first row of OHCs were involved. The entire length of the stereocilia, more severe in the lower part was always damaged. Expelled cytoplasm and fusion between stereocilia were frequently seen. In the chronic TTS ears, no abnormalities of stereocilia were found while in the PTS ears, a complete absence of the organ of Corti was noticed. The results of the present study clearly suggest that the status of the lower part of the stereocilia and the continuity of the cuticular plate play an important role in determining the reversibility of threshold shifts.


Stimulation with chronically implanted microelectrodes in the cochlear nucleus of the cat: histologic and physiologic effects.

The effects of several hours of continuous electrical stimulation in the cats' cochlear nucleus with chronically implanted activated iridium microelectrodes was investigated from the changes in the evoked response near the inferior colliculus and also by histologic evaluation of the stimulated tissue. The stimulating microelectrodes had geometric surface areas of 75-500 microns2. They were pulsed continuously for 4 h, at a pulse repetition rate of 200 Hz, using charge-balanced pulse pairs. The charge per phase was 1.8 or 3.6 nC/ph. The animals were sacrificed for histologic evaluation 2 h, or several days later. The only remarkable histologic change resulting from the 4 h of stimulation was some aggregation of lymphocytes at the site of stimulation. However, depression of the electrical excitability of neurons near the sites often persisted for several days after 4 h of stimulation at 3.6 nC/phase. The charge per phase of the stimulus pulse pair was correlated strongly with the depression of excitability, and there was a weaker correlation between the depression and the amplitude of the first phase of voltage transient induced across the electrode-tissue interface. The charge density, calculated from the geometric surface area of the stimulating electrodes, was poorly correlated with the severity of the depression. The findings suggest a means of detecting impending stimulation-induced neural damage while it is still reversible.


Influence of experimentally elevated blood viscosity on the auditory nerve-brainstem evoked response and threshold.

Blood viscosity, due to its effect on blood flow, is one of the determinants of oxygen delivery. Therefore the influence of elevated blood viscosity on hearing was studied in rats using the auditory brainstem response (ABR) threshold, wave 1 latency, brainstem transmission time (BTT) and wave 1/4 amplitude ratio. Whole blood viscosity (WBV) was elevated by 15-21% in two different ways: elevating the hematocrit (Polycythemia) by acclimation in a hypobaric chamber, or elevating the plasma viscosity by infusing a solution of Polyvinylpyrrolidone-360 (PVP). ABR was recorded before and 24 h after the blood viscosity was elevated, so that each rat served as its own control. Paired t-tests showed that there was no statistically significant difference in the ABR parameters in each of the groups as a consequence of blood viscosity elevation. In conclusion, the elevation of WBV to this degree for this duration, using two different techniques had no effect either on the function of the auditory nerve and the more peripheral sites, or on the central auditory pathway as studied by ABR.


Cochlear pathology following chronic electrical stimulation of the auditory nerve. I: Normal hearing kittens.

The present study examines the histopathological effects of long-term intracochlear electrical stimulation in young normal hearing animals. Eight-week old kittens were implanted with scala tympani electrode arrays and stimulated for periods of up to 1500 h using charge balanced biphasic current pulses at charge densities in the range 21-52 microC cm-2 geom. per phase. Both click and electrically evoked auditory brainstem responses were periodically recorded to monitor the status of the hair cell and spiral ganglion cell populations. In addition, the impedance of the stimulating electrodes was measured daily to monitor their electrical characteristics during chronic implantation. Histopathological examination of the cochleas showed no evidence of stimulus induced damage to cochlear structures when compared with implanted, unstimulated control cochleas. Indeed, there was no statistically significant difference in the ganglion cell density adjacent to the stimulating electrodes when compared with a similar population in implanted control cochleas. In addition, hair cell loss, which was restricted to regions adjacent to the electrode array, was not influenced by the degree of electrical stimulation. These histopathological findings were consistent with the evoked potential recordings. Finally, electrode impedance data correlated well with the degree of tissue growth observed within the scala tympani. The present findings indicate that the young mammalian cochlea is no more susceptible to cochlear pathology following chronic implantation and electrical stimulation than is the adult.


Selective amplification and partial sequencing of cDNAs encoding G protein alpha subunits from cochlear tissues.

An approach utilizing the polymerase chain reaction (PCR) was devised to clone members of a family of cDNAs encoding the alpha subunit of G proteins in the cochlea. RNA was extracted from the whole cochlea of the mouse and from the organ of Corti or the lateral wall of the cochlea microdissected from the guinea pig cochlea. The RNA was reverse-transcribed to cDNA which was selectively amplified by PCR using degenerate primers corresponding to two conserved regions of the G protein coding sequence. PCR products were cloned into a plasmid for sequencing. The following seven cDNA clones of particular interest were obtained: three clones putatively coding for part of the alpha-subunit of a stimulatory G protein (Gs), one clone putatively coding for part of the alpha-subunit of an inhibitory G protein (Gi) and three clones putatively coding for part of the alpha-subunit of a transducin (Gi)-like protein. Possible functions in the cochlea of putative G proteins with alpha-subunits partly encoded by these cDNA clones are briefly discussed and future studies are suggested.


Area change and volume displacement of the human tympanic membrane under static pressure.

Direct measurements are presented of the area change and volume displacement of a human tympanic membrane under static pressures in the range of -1.6 KPa to +1.6 kPa. The area change is given separately for the pars tensa and the pars flaccida. For the pars tensa a strong asymmetry in area change under positive and negative pressure is observed. The volume displacement is also given separately for the pars tensa and the pars flaccida. The volume displacement of the entire TM agrees very well with volume displacement data in literature on tympanometry. It is shown further that a linear relationship between umbo displacement and volume displacement exists. The compliance of the tympanic membrane under static pressure load is compared to acoustic compliance measurements at low frequencies, and found to be a factor 2.5 higher than the compliance at 500 Hz.


Adaptation and recovery from adaptation of the auditory nerve neurophonic (ANN) using long duration tones.

The time course of the interaction between adaptation and the recovery from adaptation of the auditory nerve neurophonic (ANN) responses was examined. The interaction between the process of recovery and the adaptation process of long probe tones which follow a masker, the so called whole tone recovery, was determined for the ANN response for different silent intervals between masker offset and probe onset. The auditory nerve neurophonic (ANN) reflects the ensemble response of phase-locked firing in single auditory nerve fibers to sustained signals. Consequently, neural response properties such as adaptation and recovery from adaptation of these coherent, time-locked responses can be studied. Recovery from adaptation was determined by recording the response of a 290 ms duration probe tone following a 100 ms masker tone, equal in frequency to the probe, ranging from -5 to 20 dB relative to the probe amplitude. Two different time patterns of the whole tone recovery were observed. If short silent intervals and/or loud maskers were used, the time course of the probe tone can be described as an exponential increase in amplitude toward a steady state expressed by the equation: A(tp) = Ass-Yr e(-tp/tau Rr)-Ys e(-tp/tau Rs) ('ascending exponential'). For longer silent intervals and/or fainter maskers, the time course of the probe tone can be described by an exponential decrease expressed by the equation: A(tp) = Yr e(-tp/tau Rr) +Ys e(-tp/tau Rs) +A(ss) ('declining exponential').


Effect of reversible hypoxia on the compared time courses of endocochlear potential and 2f1-f2 distortion products.

In order to study the effects of a controlled hypoxia on the cochlear active mechanisms, the 2f1-f2 distortion product (DP) and the endocochlear potential (EP) were recorded simultaneously in the same ear, in guinea pigs artificially respired with gas mixtures containing different percentages of oxygen. The data show an important difference in the behavior of the two parameters. While the EP undergoes a reduction of amplitude starting shortly after the establishment of the hypoxia, reaches a steady state, and recovers monotonically after a return to normoxic conditions, the time course of the DP is more complex. Its level also declines shortly after the beginning of the hypoxia though it slightly lags behind the EP decline. After switching back to normoxic conditions, the DP rises with an eventual delay with respect to the EP, overshoots, and then dramatically falls again. A slow recovery subsequently takes place and normal values are reached within 5 to 10 min. These results indicate a certain independence of the DP versus the EP. During the exposure to hypoxic conditions, differences in the time course and in the variation of amplitude of the two recorded parameters seem to indicate that the DPs could be more related to the OHC physiology than to the EP. The DP post-hypoxia effect observed after a return to normoxic conditions, indicates that a normal EP is not sufficient for the generation of normal DPs. Different hypotheses which could explain the DP post-hypoxia effect are discussed.


Detection of antiphasic sinusoids added to the envelopes of high-frequency bands of noise.

Listeners' sensitivities to antiphasic sinusoids added to the envelopes of high-frequency bands of noise were measured as a function of the frequency of the sinusoid and the bandwidth of the masking noise. The stimuli were constructed such that the added sinusoid produced interaural intensive differences (IIDs) that fluctuated at a rate that was equal to the frequency of the sinusoid and was independent of the bandwidth of the masking noise. The data indicated that performance was relatively unaffected by the rate of modulation for rates between 5 and 160 Hz. Greater rates of modulation resulted in substantial degradations of performance. The results are pertinent to Zurek and Durlach's (1987) suggestions concerning the relatively small binaural masking-level differences typically measured with high-frequency signals and broadband maskers in the N0S pi configuration. Specifically, it appears that listeners' performance is greatly affected by an insensitivity to rapidly fluctuating IIDs but is relatively unaffected by any 'spectral interference' produced by masking energy beyond the monaural critical band. Interestingly, the data corroborate Grantham's (1984) insightful proposal that the binaural system may possess two independent averaging mechanisms, one for the processing of interaural temporal disparities (ITDs) and the other for the processing of IIDs.