Degradation of Methacrylate Monomers in Human Saliva

This study assessed the effect of the molecular structure of newly synthesized methacrylate monomers on their chemical stability in human saliva, whereby these monomers can be used as dental composite resins. Six model monomethacrylates and two urethane-modified BisGMA monomers were added to human saliva, and their change in concentration after 24, 48, and 72 hours were measured by high-performance liquid chromatography. Degradation of the six model monomethacrylate monomers was found to be influenced by the molecular structure, such as steric hindrance and presence of urethane bond in chemical backbone. Based on the degradation test results of these six monomers, urethane-modified BisGMA derivatives--in which the hydroxyl groups in original BisGMA monomer were substituted with alkyl isocyanate--were synthesized and subjected to degradation test. The urethane-modified BisGMA monomers showed a particular resistance to salivary hydrolysis. Results of this study thus suggested that urethane groups should be considered when designing new monomers for dental composite systems as they demonstrated improved resistance to hydrolysis.

Study on rat subcutaneous reaction to experimental polyurethane elastomers

The purpose of the study was to investigate the biocompatibility of experimental elastomers, E580 and E590. The experimental elastomers and the control--a clinically used elastomer--were implanted into the subcutaneous tissue of rats. The tissue reactions were examined histologically on the 3rd, 7th, 14th, 28th, and 56th day after implantation. It was found that there were some irritant responses in the tissues adjacent to the implanted elastomers during the first week. However, the inflammatory tissue reaction subsided substantially from the second week onwards. The stable fibrous capsule surrounding the elastomer was formed after eight weeks. The tissue responses of the control, E580, and E590 were similar. The results suggested that the long-term tissue irritation of the experimental elastomers was so low such that they have the potential to be applied clinically.

Sevoflurane anaesthesia in chickens during spontaneous and controlled ventilation

A crossover study design was used to investigate the dose-related effects of sevoflurane at end-tidal concentrations of 2.2 to 4.4 per cent on the respiratory rate, blood gases, heart rate, arterial blood pressure and ocular signs of chickens during spontaneous and controlled ventilation. The mean (sd) carbon dioxide partial pressure (PaCO2) increased as the concentration of sevoflurane increased, and was 86 (29) mmHg at an end-tidal concentration of 4.4 per cent during spontaneous ventilation, but was maintained between 29 and 42 mmHg during controlled ventilation. The heart rate increased as the concentration of sevoflurane increased during spontaneous ventilation, but did not change during controlled ventilation. Sevoflurane decreased arterial blood pressure during both spontaneous and controlled ventilation, but a dose-dependent decrease in arterial blood pressure was observed only during controlled ventilation. The mean arterial blood pressure at an end-tidal concentration of 4.4 per cent was significantly higher during spontaneous ventilation than during controlled ventilation. Controlled ventilation prevented the increases in PaCO2 and heart rate that were observed during spontaneous ventilation. The decrease in arterial blood pressure during spontaneous ventilation was less than that during controlled ventilation, possibly owing to the effects of hypercapnia.

Arrhythmogenic effect of hypercapnia in ducks anesthetized with halothane

OBJECTIVE

To determine effects of hypercapnia on arrhythmias in ducks anesthetized with halothane.

ANIMALS

12 ducks, 6 to 8 months old, weighing 1.1 to 1.6 kg.

PROCEDURES

Each duck was anesthetized with a 1.5% mixture of halothane in oxygen, and anesthetic depth was stabilized during a 20-minute period. We added CO2 to the inspired oxygen to produce CO2 partial pressures of 40, 60, and 80 mm Hg in the inspired gas mixture.The CO2 partial pressure was increased in a stepwise manner. When arrhythmias were not evident during inhalation of the gas mixture at a specific CO2 partial pressure, the CO2 partial pressure was maintained for 10 minutes before a sample was collected for blood gas analysis. When arrhythmias were detected, a sample for blood gas analysis was collected after the CO2 partial pressure was maintained for at least 2 minutes, and CO2 inhalation then was terminated.

RESULTS

During the stabilization period, PaCO2 (mean +/- SD) was 33 +/- 5 mm Hg,and arrhythmias were not detected. In 6 ducks, arrhythmias such as unifocal and multifocal premature ventricular contractions developed during inhalation of CO2. Mean PaCO2 at which arrhythmias developed was 67 +/- 12 mm Hg. In 5 of 6 ducks with arrhythmias, the arrhythmias disappeared after CO2 inhalation was terminated.

CONCLUSION AND CLINICAL RELEVANCE

Analysis of data from this study indicated that hypercapnia can lead to arrhythmias in ducks during halothane-induced anesthesia. Thus, ventilatory support to maintain normocapnia is important for managing ducks anesthetized with halothane.

Environmental effects on acidic lipids of thylakoid membranes

The contents of the chloroplast acidic lipids, SQDG (sulphoquinovosyldiacylglycerol) and PG (phosphatidylglycerol), were reduced in the cells of Chlamydomonas reinhartdtii with exposure to sulphur- or phosphorus-source limitation, respectively. The decrease in the content of one acidic lipid was accompanied by an increase in the content of the other acidic lipid, which resulted in the maintenance of a certain level of total acidic lipids of chloroplast membranes. On the other hand, the content of each acidic lipid was little affected by temperature stresses during cell growth.

Direct evidence for requirement of phosphatidylglycerol in photosystem II of photosynthesis

Phosphatidylglycerol (PG) is considered to play an important role in the ordered assembly and structural maintenance of the photosynthetic apparatus in thylakoid membranes. However, its function in photosynthesis remains poorly understood. In this study we have identified a pgsA gene of Synechocystis sp. PCC6803 that encodes a PG phosphate synthase involved in the biosynthesis of PG. A disruption of the pgsA gene allowed us to manipulate the content of PG in thylakoid membranes and to investigate the function of PG in photosynthesis. The obtained pgsA mutant could grow only in the medium containing PG, and the photosynthetic activity of the pgsA mutant dramatically decreased with a concomitant decrease of PG content in thylakoid membranes when the cells grown in the presence of PG were transferred to the medium without PG. This decrease of photosynthetic activity was attributed to the decrease of photosystem (PS)II activity, but not to the decrease in PSI activity. These findings demonstrate that PG is essential for growth of Synechocystis sp. PCC6803 and provide the first direct evidence that PG plays an important role in PSII.

Requirement of phosphatidylglycerol for photosynthetic function in thylakoid membranes

To investigate the role of phosphatidylglycerol (PG) in photosynthesis, we constructed a mutant defective in the CDP-diacylglycerol synthase gene from a cyanobacterium, Synechocystis sp. PCC6803. The mutant, designated as SNC1, required PG supplementation for growth. Growth was repressed in PG-free medium concomitantly with the decrease in cellular content of PG. These results indicate that PG is essential, and that SNC1 is defective in PG synthesis. Decrease in PG content was accompanied by a reduction in the cellular content of chlorophyll, but with little effect on the contents of phycobilisome pigments, which showed that levels of chlorophyll-protein complexes decreased without alteration of those of phycobilisomes. Regardless of the decrease in the PG content, CO(2)-dependent photosynthesis by SNC1 was similar to that by the wild type on a chlorophyll basis, but consequently became lower on a cell basis. Simultaneously, the ratio of oxygen evolution of photosystem II (PSII) measured with p-benzoquinone to that of CO(2)-dependent photosynthesis, which ranged between 1.3 and 1.7 in the wild type. However, it was decreased in SNC1 from 1.3 to 0.4 during the early growth phase where chlorophyll content and CO(2)-dependent photosynthesis were little affected, and then finally to 0.1, suggesting that PSII first lost its ability to reduce p-benzoquinone and then decreased in its level and actual activity. These results indicate that PG contributes to the accumulation of chlorophyll-protein complexes in thylakoid membranes, and also to normal functioning of PSII.

A comparison of distilled water and normal saline as diluents for endobronchial administration of epinephrine in the dog

We compared the effects of distilled water and normal saline as diluents for the endobronchial administration of epinephrine in anesthetized dogs by using a cross-over design. Six dogs received 2 mL of either normal saline or distilled water into the bronchus, and the other solution was administered 1 wk later. Eight dogs received 0.02 mg/kg epinephrine diluted in either distilled water (E + water) or normal saline (E + saline) to a total volume of 2 mL into the bronchus, and the other solution was administered 1 wk later. Normal saline or distilled water without epinephrine did not affect the plasma epinephrine concentration, mean arterial pressure (MAP), and PaO(2). The peak plasma epinephrine concentration was significantly larger after treatment with E + water (26.5 +/- 7.9 ng/mL) than after E + saline (2.1 +/- 0.7 ng/mL). E + water caused an increase in MAP of 91 +/- 24 mm Hg, whereas E + saline did not affect MAP. The maximal decrease in PaO(2) after the administration of E + water (14 +/- 5 mm Hg) was significantly greater than after E + saline (7 +/- 2 mm Hg). In conclusion, distilled water as the diluent for endobronchially administered epinephrine to a total volume of 2 mL allowed better absorption of epinephrine compared with normal saline without a serious detrimental effect on PaO(2).

IMPLICATIONS

Using a small volume of distilled water as the diluent for endobronchial epinephrine administration significantly increased epinephrine absorption and arterial pressure in comparison with normal saline, without having a serious detrimental effect on PaO(2), in an anesthetized, noncardiopulmonary, resuscitation dog model.

Dose-related cardiovascular effects of isoflurane in chickens during controlled ventilation

We studied cardiovascular effects of isoflurane in chickens during controlled ventilation. Following the determination of the minimal anesthetic concentration from the response to clamping of a digit, dose-related effect of isoflurane on heart rate and arterial pressure were studied. The minimal anesthetic concentration of isoflurane was 1.25 +/- 0.13% (mean +/- SD, n=9). There was a dose-dependent decrease in arterial pressure. The heart rate did not change significantly over a range of 1 to 2 times the minimal anesthetic concentration.

Evaluation of intracranial pressure by transcranial Doppler ultrasonography in dogs with intracranial hypertension

Transcranial Doppler ultrasonography (TCD) has been used to confirm changes in cerebral hemodynamics. In this study, we investigated whether the parameters for the basilar artery measured by TCD were correlated with the intracranial and cerebral perfusion pressures in extreme intracranial hypertension. An intracranial hypertension model was produced in seven dogs by inflating a balloon inserted into the epidural space. The resistance index was compared with the corresponding intracranial pressure and cerebral perfusion pressure values during intracranial hypertension. A significant correlation was recognized between the resistance index and cerebral perfusion pressure. Therefore, measurement of the basilar artery by TCD in the dog with intracranial hypertension is useful in estimating the intracranial circulation in cases where the measurement of intracranial pressure is not available or not indicated.

Non-invasive diagnosis of ischemic brain damage after cardiopulmonary resuscitation in dogs by using transcranial Doppler ultrasonography

We have attempted to identify whether it is possible to utilize transcranial Doppler ultrasonography to evaluate the brain damage that occurs after resuscitation from 3 min (control group) and 12 min (damage group) of cardiac arrest in dogs. In this study we used transcranial Doppler ultrasonography to follow the basilar arterial flow and middle cerebral arterial flow for 180 min following the induction of cardiac arrests. Two abnormal waveform patterns (the "to-and-fro" and "diastolic no-flow" patterns) were found in all dogs in the damage group whereas abnormal waveforms were not detected in the control group. Pathological diagnosis revealed that, compared with the control group, the damage group recognized ischemic alteration at the level of the hippocampus and caudate nucleus. In conclusion, this study shows that the basilar arterial flow of observed with transcranial Doppler ultrasonography may be use for the prediction of outcome and the diagnosis of brain damage in the dog.

The comparison between the cerebral blood flow directly measures and cerebral blood flow velocity in the middle and basilar cerebral arteries measured by transcranial Doppler ultrasonography

Transcranial Doppler ultrasonography (TCD) may be useful for determining alterations in cerebral blood flow (CBF) during excessive hemodynamic changes by non-invasive measurement of the CBF velocity. The purpose of this study was to measure the correlation between CBF and the middle cerebral artery (MCA) and basilar artery (BA) flow velocities, as measured by TCD during excessive hemodynamic changes produced by hypertension and hypotension in adult dogs. The peak, diastolic, and mean flow velocities were measured by TCD. Arterial hypertension was induced by administration of dopamine at 5 and 15 microg/kg/min, and hypotension was induced by hemorrhage. During the hemodynamic changes, the BA velocity correlated more closely with the alteration in the CBF than the MCA velocity. In terms of percentages of the values during anesthesia, there was good correlation between CBF and the MCA and BA velocities. In conclusion, our findings indicate that MCA and BA velocity measurements, as a percentage of the values during anesthesia, both give an equally accurate indication of alterations in CBF during excessive hemodynamic changes.

Effects of respiratory cycle on pulmonary venous flow and cardiac cycle on pulmonary venous diameter of dogs: a transesophageal echocardiography study

We investigated 12 anesthetized normal dogs using transesophageal echocardiography to understand the effects of respiration on the pulmonary venous flow. Additionally, we observed whether the diameter of the pulmonary vein changes with the heart beat. The pulsed Doppler wave form of pulmonary venous flow predominantly demonstrated two backward flows, with one peak occurring during ventricular systole and another during ventricular diastole. Sometimes a small forward flow occurred during left atrial contraction. In comparison with expiration, the peak velocity and velocity-time integral of the flow wave under inspiration occurred during both systole and diastole were significantly smaller. The diameter of the pulmonary vein decreased during left atrial contraction and increased during left ventricular systole and diastole.

Pulmonary venous flow in normal dogs recorded by transthoracic echocardiography: techniques, anatomic validations and flow characteristics

To observe pulmonary venous flow in dogs, the echocardiographic imaging planes and the techniques for examination, and the validations of anatomic location were investigated. Then, the velocity pattern of pulmonary venous flow was recorded in normal conscious dogs. Six imaging planes were available for observing the right or left caudal lobe pulmonary venous flow with two-dimensional or pulsed Doppler echocardiography. Of these, the left lateral apical 4-chamber view can be applied as standard view, because the pulmonary venous flow and transmitral flow could be recorded in this view simultaneously with small sampling angle. The velocity pattern of pulmonary venous flow demonstrated two forward waves in 19 of 20 dogs examined, with one peak occurring during ventricular systole and another during ventricular diastole. A reversed flow during atrial contraction was also seen in 11 dogs. In the two forward waves, the mean peak velocity and velocity-time integral of ventricular diastolic forward flow were significantly higher than those of systolic forward flow (46.49 +/- 6.79 vs. 31.13 +/- 4.92 cm/s, p < 0.0001 and 8.18 +/- 1.84 vs. 5.14 +/- 0.82 cm, p < 0.0001, respectively). The deceleration time of diastolic forward flow shortened with the increase of heart rate (r = -0.87, p < 0.0001). Pulmonary venous flow in dogs can be observed under transthoracic two-dimensional or pulsed Doppler echocardiography.

Comparison of systemic and renal hemodynamics measured by Doppler ultrasonography in canine experimental hypovolemia

The aim of this study was to examine renal hemodynamics at the hypovolemic and recovery phases in two different hypovolemic shock models using Doppler ultrasonography, and to compare this with systemic hemodynamics. In experiment 1, the hypovolemic phase was induced in 6 mongrel dogs by removing arterial blood at 30 ml/kg for 60 min. In the recovery phase, this blood was reinfused at 30 ml/kg over 60 min. In experiment 2, hypovolemia was induced in 12 beagle dogs by rapid blood removal until blood pressure decreased to 40 mmHg and was maintained at this pressure for 30 min. Six of the dogs were then infused with 20 ml/kg hydroxyethyl starch over 5 min, and the other 6 were infused with 60 ml/kg lactated Ringer's solution also over 5 min. Parameters for systemic and renal hemodynamics were measured by using a polygraph and the Doppler method, respectively. The decrease of diastolic blood flow, resulted in an increase of vessel resistance, and was detected in the hypovolemic kidney by the Doppler method. The rapid and large volume infusion of resuscitation fluids was effective for the recovery of both systemic circulation and renal blood flow, however this induced an increase of kidney vessel resistance, a result of the autoregulation mechanism of the kidney. The changes in these parameters at the main renal artery and interlobar artery were similar.

Ultrasonography and angiographic examination of normal canine liver vessels

The aim of this study is to provide a description of the ultrasonographic and angiographic anatomy of the hepatic and portal veins in normal dogs. Knowledge of this anatomy is essential for the proper diagnosis and correction of hepatic vessel anomalies like portal systemic shunts. Cranial mesenteric portography was done in 10 adult mongrel dogs to visualize the portal vein and its branches while the hepatic veins were visualized using the transvenous retrograde angiography method. Longitudinal and transverse ultrasound scans of the liver were done in the same dogs in left and right lateral positions in order to determine the best positions for imaging the different liver vessels. The distribution pattern of the hepatic and portal veins could be demonstrated by both ultrasonography and contrast angiography. Hepatic arteries are not usually visualized ultrasonographically. Ultrasound provided dynamic information that could not be obtained by contrast radiography. Super imposition of all vessels in the angiographic studies made the description of the branches of the liver vessels difficult. The results of the present study suggest that both methods may provide important complementary information in the diagnosis and planning of surgical procedures for the correction of vessel anomalies in the canine liver.

Changes of serum cytokine activities and other parameters in dogs with experimentally induced endotoxic shock

To study the relationship of changes of cytokines in endotoxic shock, serum tumor necrosis factor (TNF), interleukin (IL)-1 and IL-6 like activities, together with physiologic and hemodynamic responses, were examined in dogs before and after intravenous administration of lipopolysaccharide (LPS) purified from Escherichia coli in a dose of 500 micrograms/kg of body weight. The blood endotoxin concentration increased significantly at 30 min after LPS administration, and maintained high levels for 24 hr. Red blood cell counts; hemoglobin concentration and hematocrit values increased at 30 min, and these high values persisted for 24 hr. The platelet count decreased significantly at 30 min, then showed a tendency to recover, but decreased again at 24 hr. Cardiac output, cardiac index and mean arterial pressure showed transient, significant decreases at 15 min, and then returned to the baseline levels by 24 hr. TNF-like activities increased at 30 min, while IL-1-like activities did so between 30 and 60 min. The former reached the maximal levels at 2 hr and the latter at 1.5 hr. Both activities were then hardly detectable from 6 to 24 hr. IL-6-like activities elevated at 1 hr with the peak at 1.5 hr, and remained high until 24 hr.

Compression of spinal cord caused by spinal deformation in a cat

An 8-month-old cat with bilateral hindlimb paresis was admitted. Radiography revealed a curvature of the thoracic spine and a partial deformation of thoracolumbar vertebrae (dorsal extrusion of the cranial and caudal edges). Compression of the spinal cord (T9-L1 and L6-7) was found by myelography. Medicinal treatment did not yield the desired result. Hemilaminectomy and laminectomy were done to relieve pressure on the spinal cord leading to improved gait. It is, however, not clear whether this syndrome was primarily caused by metabolic or genetic factors.

Sandwich enzyme-linked immunosorbent assay for quantitative measurement of serum amyloid A protein in horses

To measure the concentration of serum amyloid A (sAA) protein in horses, a sensitive and highly reproducible sandwich (ELISA) was established, using affinity purified SAA antibody. Results of the ELISA were found to have a high correlation (r = 0.95) with those of the single radial immunodiffusion test. Equine SAA concentration was measured by use of this ELISA. In clinically normal horses, the concentration of SAA was high immediately after birth to 2 weeks of age. After that, SAA concentration had periodic fluctuations in the range of approximately 1.0 to 30 micrograms/ml. Mean (+/- SD)) concentrations of SAA in foals (< or = 12 months old) and adult horses (> or = 18 months old) were 21.23 +/- 12.20 and 14.93 +/- 9.07 micrograms/ml, respectively. In mares during the perinatal period, SAA concentration remained stable within the reference range before parturition. It increased quickly after delivery, and reached a peak value of 101.29 +/- 98.82 micrograms/ml on postpartum day 3, then began to decrease, at postpartum week 2, to the reference range by the end of postpartum month 1. In horses with experimentally induced inflammation, SAA concentration increased quickly and reached approximately four- to 40-fold increase over the pretreatment value on day 1 and remained high on days 2 to 6 after treatment. It then returned to the baseline value by 2 to 4 weeks in association with disappearance of local signs of inflammation. The SAA concentration was high in most horses with clinical signs of inflammation. It was concluded from these data that this ELISA is sensitive and reliable for measuring SAA in horses.

Quantitative measurement of canine renal arterial blood flow using Doppler ultrasonography

The aim of this study was to estimate the accuracy of the quantitative measurement of renal blood flow using the non-invasive method, Doppler ultrasonography. First, we determined a method of approach to the renal artery in order to detect the rate and pattern of flow, using 8 adult beagles under general anesthesia. Secondly, we examined the renal arterial blood flow using the Doppler method and electromagnetic flowmeter using 7 mongrel dogs. A significant correlation (r = 0.879; p < 0.01) was found between two methods, though the Doppler system tended to indicate high values than the electromagnetic flowmeter. Our study suggests that the Doppler method is a useful non-invasive technique of measuring renal blood flow in the dog.

Congenital lymphedema in a calf with lymph node dysplasia or aplasia

A 9-month-old male Japanese Black calf with subcutaneous edema in mainly both limbs was investigated. Necropsy revealed about 20 l of ascites and severe edema in the large omentum, abomasal folds, conjunctiva and rectum. Only small internal iliac and hepatic lymph nodes were found. Histopathology revealed lymph node dysplasia showing excess trabecular formation, reticular cell proliferation, and obvious dilation of both afferent and efferent lymphatics. These findings suggest that disturbance of lymphatic flow with congenital lymph nodes dyspalsia or aplasia resulted in lymphedema in this calf.

Comparison of extravascular lung water volume with radiographic findings in dogs with experimentally increased permeability pulmonary edema

The relationship between extravascular lung water volume (ELWV) and chest radiographical findings was studied in general-anesthetized beagles. The dogs were experimentally injected with oleic acid to increase pulmonary vascular permeability. When the ELWV value in the dogs increased more than approximately 37% from the control value, their chest radiographs began to show signs of pulmonary edema. At this time, the chest X-ray density increased to 10% above the control level. PaO2 decreased, and PaCO2 increased after the administration of oleic acid. This clearly showed that the pulmonary gas exchange function was reduced following increasing ELWV. This comparison showed that probably the thermal-sodium double indicator dilution measurement of ELWV can detect slight hyperpermeability pulmonary edema that does not show on chest radiographs. The chest radiograph was therefore not suitable for the detection of slight pulmonary edema, because it did not show any changes in the early stages in hyperpermeability pulmonary edema.

Transmigration of fluid rapidly infused into dogs with renal blood vessels ligation and increased pulmonary capillary permeability

To study the transmigration of fluid rapidly infused intravenously, lactated-Ringer's solution was infused at the rate of 90 ml/kg/hr for 30 min into generally anesthetized dogs. Four groups were made; group C with no fluid infusion as the control, group F with rapid fluid infusion only, group LF with renal blood vessels ligation and rapid fluid infusion, and group OF with increased pulmonary capillary permeability experimentally induced by oleic acid and rapid fluid infusion. The extravascular lung water volume (ELWV) was measured by the thermal-sodium double indicator dilution method, and the amounts of ascites and urine, and other clinical parameters were monitored before and after fluid infusion. The results show that in the dogs without increased pulmonary capillary permeability excessive fluid is mainly excreted as urine (group F) or transudates into the abdominal cavity (group LF). But in the dogs with increased pulmonary capillary permeability (group OF) excessive fluid easily and rapidly transudated into the pulmonary interstitium, resulting in pulmonary edema.

Canine acute phase response: relationship between serum cytokine activity and acute phase protein in dogs

The changes in serum activity of interleukin (IL)-1, IL-6, and tumor necrosis factor (TNF) were studied in dogs with acute inflammation. Dogs with local inflammation induced by an intramuscular injection of turpentine oil showed clinically a typical progression in the inflammatory response, recovering on day 14 after the treatment. Serum concentrations of C-reactive protein (CRP) and alpha 1 acid glycoprotein (alpha 1AG) increased, and the albumin concentration decreased in all dogs during the acute phase response. These values each returned to the normal range from day 14 to 21. Serum IL-6-like activity was detected from 2 hr to day 6 after treatment. Serum TNF-like activity in the treatment group was detected at a low level from 3 to 24 hr after treatment, but there was no statistically significant difference compared with the control group. The temporal changes in serum IL-6 and TNF-like activities preceded those in serum concentrations of CRP, alpha 1 AG, and albumin. No dogs showed a detectable rise in serum IL-1-like activity after treatment.

Role of lymphocytes in spontaneous regression of experimentally transplanted canine transmissible venereal sarcoma

Sensitized peripheral blood lymphocytes (PBL) obtained from canine transmissible venereal sarcoma (CTVS)-regressed dogs were more cytotoxic against CTVS cells than non-sensitized PBL from untreated dogs. Cytotoxicity shown by sensitized PBL was inhibited significantly by the addition of anti-major histocompatibility complex (MHC) class II mouse monoclonal antibody as well as that of anti-dog thymocyte rabbit serum. The degree of cytotoxic activity shown by lymphokine activated killer (LAK) cells induced from non-sensitized or sensitized PBL was similar to that of the activity shown by sensitized PBL. These LAK activities were also prohibited by the addition of anti-dog thymocyte rabbit serum. Immunohistochemical examination demonstrated that MHC class II antigens were expressed on the surface membrane of CTVS cells and thymocyte antigens were detected on the surface of the tumor infiltrating lymphocytes. From the results mentioned above, lymphocytes which play a central role in tumor regression are considered to be T cells. These cells might recognize MHC class II antigens on the surface membrane of CTVS cells in tumor regression.

Comparison of methods of cardiac output measurements determined by dye dilution, pulsed Doppler echocardiography and thermodilution in horses

Cardiac output (CO) measurements by the three methods of dye dilution, pulsed Doppler echocardiography and thermodilution in horses under anesthetized conditions were compared. Although CO determined by the thermodilution method was slightly higher than those obtained by the other two methods, the measurements by all methods showed almost similar results. The coefficients of correlation between the dye dilution and thermodilution methods, the dye dilution and pulsed Doppler echocardiography methods, and the thermodilution and pulsed Doppler echocardiography methods were 0.87, 0.89, and 0.88, respectively (P < 0.01). These results indicate that pulsed Doppler echocardiography and thermodilution methods could be no less useful than the traditional dye dilution method for evaluating of CO in horses. The pulsed Doppler echocardiography method may offer some advantage over other two methods; it is non-invasive and enables continuous measurement of CO.

Bioassay for interleukin-1, interleukin-6, and tumor necrosis factor-like activities in canine sera

To measure interleukin (IL)-1, IL-6, and tumor necrosis factor (TNF)-like activities in canine serum, bioassays were conducted using human melanoma A375S1, IL-6 dependent murine hybridoma MH60.BSF2, and WEHI 164 murine sarcoma subclone 28-4. Clinically normal adult beagles were experimentally induced endotoxic shock by an intravenous injection of lipopolysaccharide or local inflammation by an intramuscular injection of turpentine oil. IL-1-like activity was detected in sera from dogs with endotoxic shock. IL-6 and TNF-like activities were detected in sera from both dogs with endotoxic shock and local inflammation. IL-1-like activity in sera from the dogs with endotoxic shock declined after dilution with either medium or serum obtained before treatment (pre-serum), but the IL-1-like activity was maintained to a greater extent in samples diluted with pre-serum compared to those diluted with medium. TNF-like activity declined equally after dilution with either medium or pre-serum. On the other hand, IL-6-like activity was inhibited at low dilution. It was, therefore, necessary to dilute the serum samples to 1:180 from dogs with endotoxic shock or 1:60 from dogs with local inflammation, in order to minimize the effect of inhibitory factors on IL-6-like activity. IL-6-like activity was neutralized by monoclonal antibody against murine IL-6 receptors. TNF-like activity was neutralized by anti-mouse TNF alpha rabbit serum. However IL-1-like activity was not neutralized by either anti-mouse or anti-human IL-1 rabbit serum.

Characterization of dog interleukin-2 activity

Proliferative activity of murine interleukin-2 (IL-2) dependent T cells (CTLL-2) was detected in the culture supernatant of canine peripheral blood lymphocytes (PBL) stimulated with phytohemagglutinin-P (PHA-P), and was defined as dog IL-2. The highest production of IL-2 was obtained under the conditions in which a PBL population of 2 x 10(6) cells/ml was stimulated with PHA-P at a concentration of 10 micrograms/ml at 38 degrees C for 48 hr. Dog IL-2 activity was significantly inhibited by heating at 65 degrees C, acidification under pH 4, alkalification over pH 10, and trypsin exposure. A peak of dog IL-2 activity was detected in the fraction with a molecular weight of approximately 31,000 by gel filtration. Long-term culture of canine lymphocytes was successful over 10 passages by using dog IL-2 with PHA-P-stimulation every 3 passages. The cultured cells mostly consisted of small- and medium-sized lymphocytes. These cells reacted to anti-dog thymocyte rabbit serum and anti-dog Thy-1 mouse monoclonal antibody. These cells were therefore considered to originate in T-lineage lymphocytes. Cytostasis of PBL from intact dogs reacting to canine transmissible venereal sarcoma cells was increased significantly when PBL was cultured for more than 30 days with homologous IL-2.

Evaluation of serum amyloid A protein as an acute-phase reactive protein in horses

Serum amyloid A protein (SAA) was isolated from equine acute-phase serum by repeating Sephadex G-75 gel filtration 3 times. Quantitative measurement of equine SAA was performed by the single radial immunodiffusion technique with rabbit anti-equine SAA serum. In clinically normal horses, the SAA concentration remained relatively high from immediately after birth up to 1 week of age. After this the concentration showed periodic fluctiation in the range of approximately 13 to 30 micrograms/ml. The mean (+/- SD) concentration of SAA in foals (< or = 12 months old) and in adult horses (> or = 18 months old) was 19.37 +/- 9.41 and 21.53 +/- 9.81 micrograms/ml, respectively. In mares during the perinatal period, the SAA concentration remained stable and within the normal range for 4 months before parturition. After foaling, it increased quickly and reached a peak value of 136.78 +/- 56.74 micrograms/ml on day 3 postpartum, and then began to decrease at 2 weeks postpartum returning to within the normal range by 1 month postpartum. In horses with experimentally induced inflammation, the SAA concentration increased quickly, and reached the highest value, approximately 4 to 20 times higher than pre-treatment values, on day 2 after treatment. It then returned to the base line values within 10 days to 4 weeks, concurrent with the disappearance of local inflammatory signs. The SAA concentration was very high in most horses with clinical signs of inflammation. It was concluded from these data that equine SAA was a sensitive acute-phase reactive protein which increased in the early phase of various acute inflammations.

Five cases of cranial duplication in calf

Five cases of cranial duplications in calves were morphologically reported. Each calf had a single body with duplicated heads that showed various degrees of fusion. The medial sides of individual heads were asymmetrically supplied by the branches of hemilateral common carotid or lingual artery. No marked differences in the development of the duplicated head in any of the calves were observed. Cleft palates were observed in all heads. The development and general structures of the organs in the head and neck regions appeared to depend on the degree of duplication of the cranial nerves.