Measurement of glycosaminoglycans and keratan sulphate in canine arthropathies

Glycosaminoglycans (GAG) and keratan sulphate (KS) were measured in sera and synovial fluids from dogs with either osteoarthritis (OA) or rupture of the cranial cruciate ligament (CCL) and normal dogs. The dogs with OA had higher synovial fluid GAG levels (P < 0.002) and serum KS (P < 0.03) compared to the normal dogs. No significant differences in serum GAG were found in either group. In both OA and rupture of the CCL, GAG levels were increased in the synovial fluid from the affected joint compared with the clinically normal (inactive) contralateral joint. Neither GAG nor KS measurements correlated with serum and synovial fluid antibodies to collagen type II, synovial fluid white cell count or age of dog. It is unlikely that the measurement of these cartilage breakdown products is of value for diagnostic or prognostic use in canine arthropathies.

Borrelia burgdorferi infection in UK horses

Antibody levels (IgG and IgM) to Borrelia burgdorferi were measured in the sera and synovial fluids of UK horses. Western blotting against B. burgdorferi was also used on samples from seropositive horses. A low incidence of seropositivity was shown in horses from most parts of the UK. This increased in areas that have a high incidence of human and canine borreliosis (Norfolk and south coast). Leptospira infections of horses did not cause cross reactions in the B. burgdorferi ELISA. Most horses did not display clinical signs of Lyme disease. As with dogs and man, it is apparent that B. burgdorferi infection occurs in horses in the UK but clinical Lyme disease is uncommon.

Acute arthritis of cats associated with feline calicivirus infection

Twelve specific pathogen-free cats were infected either by intra-articular inoculation or by contact exposure to one of two strains of feline calicivirus (FCV), either F65, a field strain originating from an outbreak of lameness in a group of cats, or a vaccine strain. Following either route of exposure, both strains induced signs typical of FCV infection including oral and nasal ulceration, conjunctivitis and ocular discharge. These signs were of equal severity for both virus strains, but overall, following either route of infection, F65 induced more severe disease than the vaccine strain, with marked pyrexia, lethargy and lameness. Vaccine virus only induced a relatively mild lameness following intra-articular inoculation. Gross pathological and histopathological lesions were seen in some of the joints, but again changes were more severe in the F65-exposed cats. Virus was isolated from both normal and affected joints from both groups of F65-exposed cats, and from a joint from each cat inoculated intra-articularly with vaccine virus. Mild transient lameness was also seen in one of two control cats inoculated intra-articularly, but no pathological changes were seen or virus isolated from joints. A cDNA probe used in RNA dot blot hybridisation experiments was found to be specific and more sensitive than virus isolation in detecting FCV in selected tissues. This may be useful in future studies on the pathogenesis of FCV disease and in studies on viral persistence in FCV carriers.

Foscarnet for suppression of human immunodeficiency virus replication

The effect of foscarnet against human immunodeficiency virus (HIV) was evaluated in nine HIV-infected individuals; six completed 28 days of induction therapy. The overall mean increase in CD4+ lymphocytes was 64 cells per mm3. The mean decline in the HIV antigen concentration was 108 pg/ml (P = 0.03), and suppression was related to systemic foscarnet exposure by a maximum-effect pharmacodynamic model.

Cellular sources of proteolytic enzymes in equine joints

Isolated equine blood and articular cells were investigated for proteolytic enzyme production by means of gel filtration and analysis on 14C-acetylated collagen and casein substrates. Significant amounts of collagenase and caseinase activity were produced by cultured synoviocytes stimulated with equine interleukin 1, although large amounts of collagenase also originated from neutrophils.

Immune responses to canine distemper virus in joint diseases of dogs

Measurement of immune complexes, antibodies against canine distemper virus (CDV) and anti-CDV antibodies in immune complexes were made in sera and SF from 'normal' dogs and from dogs with joint diseases. These data were compared with cytological analyses of SF samples. In dogs with canine rheumatoid-like arthritis (CRA) there were correlations between circulating anti-CDV antibody levels and circulating immune complex levels (P < 0.001) and between SF anti-CDV antibody levels and SF immune complex levels (P < 0.01). Furthermore, the SF PMN count in dogs with CRA correlated with both the SF anti-CDV antibody levels (P < 0.001) and the SF immune complex anti-CDV antibody levels (P < 0.001). The results demonstrated a relationship between CDV and ongoing synovial inflammation in dogs with CRA.

Effects of a nitric oxide synthase inhibitor in humans with septic shock

OBJECTIVE

Studies in animals have indicated that increased production of nitric oxide from an inducible isoform of nitric oxide synthase contributes to the pathophysiology of endotoxic and cytokine induced shock. The aim of this study was to determine the role of nitric oxide in septic shock in humans.

METHODS

The study was a randomised, double blind, placebo controlled investigation of the effects of the nitric oxide synthase inhibitor NG monomethyl-L-arginine (L-NMMA) in 12 patients with severe sepsis associated with hypotension. Measurements of haemodynamic, haematological, and biochemical variables were made.

RESULTS

L-NMMA (0.3 and 1 mg.kg-1) produced a dose dependent increase in mean arterial pressure, systemic vascular resistance, pulmonary vascular resistance, central venous pressure, and pulmonary artery occlusion pressure, and a decrease in cardiac output and heart rate. In response to the highest dose of L-NMMA systemic vascular resistance increased from 547(SEM 92) to 889(143) dyne.s.cm-5, mean arterial blood pressure increased from 80.9(2.9) to 100.5(6.1) mm Hg, and cardiac output decreased from 11.2(2.1) to 8.9(1.9) litres.min-1. Continuous infusion of L-NMMA (1 mg.kg-1 x h-1) produced sustained haemodynamic changes. Platelet numbers decreased during the course of the study in both the L-NMMA and the placebo group and did not differ significantly between the groups.

CONCLUSIONS

Low doses of L-NMMA cause a widespread increase in vascular tone and raise blood pressure in patients with septic shock. Overproduction of nitric oxide appears to be an important mechanism in septic shock in patients, and inhibition of nitric oxide synthesis might provide a novel therapeutic approach to this condition. However, L-NMMA produced a fall in cardiac output and it is possible that this would worsen tissue perfusion. Larger studies examining the effects of L-NMMA on mortality and morbidity are now required.

Proteolytic enzymes in equine joints with infectious arthritis

Significant amounts of collagenase and caseinase activity were detected in infected synovial fluid samples. Partial characterisation of the enzymes by gel filtration suggested that synovial fluid from cases of infectious arthritis may contain enzymes from both the synovial cells and neutrophils. This finding was also supported by analysis of sequential synovial fluid samples from 4 infected joints. In 3 joints the concentration of caseinase and in 1 joint collagenase paralleled the decline in total nucleated cell count. However, in 3 joints the concentration of collagenase remained high after the total nucleated cell count had returned to normal, suggesting that this enzyme originated from resident articular cells.

Inhibition and inactivation of murine hepatic ethoxy- and pentoxyresorufin O-dealkylase by naturally occurring coumarins

The present study was designed to evaluate the effects of a series of natural coumarins on ethoxyresorufin O-dealkylase (EROD) and pentoxyresorufin O-dealkylase (PROD) activities in vitro using hepatic tissues from SENCAR mice. Fifteen different coumarins were examined for potential modulating activities. Several naturally occurring coumarins, found in the human diet, were effective inhibitors of hepatic EROD activity in vitro, including coriandrin, bergamottin, isoimperatorin, and ostruthin. Notably, coriandrin and bergamottin were approximately as potent as 7,8-benzoflavone, a relatively selective inhibitor of cytochrome P450 1A1. Several naturally occurring coumarins were also potent inhibitors of hepatic PROD activity, including imperatorin, bergamottin, isopimpinellin, and angelicin. Kinetic studies of the type of inhibition revealed that these compounds inhibited hepatic EROD and PROD activity by a variety of modes rather than by a uniform one. Furthermore, experiments using a two-stage incubation assay revealed that coriandrin, imperatorin, ostruthin, and several other natural coumarins inactivated hepatic EROD activity (i.e., predominantly cytochrome P450 1A1-mediated) and that isopimpinellin inactivated hepatic PROD activity (i.e., predominantly cytochrome P450 2B1-mediated). Finally, the results indicate that some coumarins had selective inhibitory effects for EROD vs PROD and preliminary analyses suggested a possible structural basis for the observed differences. The current data suggest that certain naturally occurring coumarins, to which humans are exposed in the diet, are potent modulators of cytochrome P450. Furthermore, these compounds may be capable of influencing the metabolic activation of other xenobiotics, including chemical carcinogens.

The Bicore pulmonary monitor. A device to assess the work of breathing while weaning from mechanical ventilation

The Bicore CP-100 pulmonary monitor offers the advantage of continuous pulmonary monitoring at the bedside. Using an easily placed oesophageal balloon catheter and a flow transducer within the ventilator system, intrathoracic pressures, airway pressures and airway flow can be measured, and from these the Bicore calculates 25 other respiratory variables. The monitor screen displays real time waveforms of airway pressure, airway flow, oesophageal pressure and inspired tidal volume, and with these data it should be possible to determine more accurately when patients can be weaned from mechanical ventilation. It should also be possible to assess objectively the onset of respiratory fatigue and failure so that intervention can take place at an earlier stage. To assess the ease of use and potential benefit, the Bicore was used to calculate the work of breathing while weaning eight patients from mechanical ventilation in a spontaneous breathing mode. The pressure support ranged from 20 cmH2O, 10 cmH2O and 5 cmH2O, to a continuous positive airway pressure of 5 cmH2O, all with a positive end-expiratory pressure of 5 cmH2O, down to a single T-circuit with no positive airway pressure or end-expiratory pressure. The work of breathing while on a Veola Hamilton ventilator was found to be about the same, while receiving pressure support of 20 cmH2O compared to a continuous positive airway pressure of 5; the other forms of respiratory support increased the work of breathing significantly.

Oligonucleotide fingerprinting of isolates of Candida species other than C. albicans and of atypical Candida species from human immunodeficiency virus-positive and AIDS patients

Oligonucleotide fingerprinting of genomic DNA from oral isolates of four different Candida species other than C. albicans and atypical chlamydospore-positive isolates from human immunodeficiency virus (HIV)-positive individuals and AIDS patients was investigated as a means for differentiating between isolates within individual species. Oligonucleotides composed of simple repetitive sequence motifs, including (GACA)4, (GATA)4, (GGAT)4, (GTG)5, and (GT)8, all yielded fingerprints suitable for strain segregation of 8 C. tropicalis isolates, 12 Torulopsis (Candida) glabrata isolates, 8 atypical Candida isolates, and, except for (GATA)4, 2 C. krusei probe in turn and so generate several distinct DNA fingerprints of the same DNA sample. However, none of the probes yielded fingerprints suitable for strain segregation with three C. parapsilosis isolates. The (GATA)4 probe was also used to detect restriction fragment length polymorphisms among a genetically closely related group of atypical Candida isolates on primary isolation from an additional HIV-infected patient. These chlamydospore-positive atypical Candida isolates were sucrose positive, were of C. albicans serotype A, hybridized weakly with the C. albicans-specific mid-repeat sequence probe 27A, and yielded fingerprint profiles by random polymorphic DNA analysis that were distinct from those derived from C. albicans isolates. The C. stellatoidea ex-type strain NCPF 3108 was indistinguishable from the atypical Candida isolates in all these tests and also yielded an identical carbohydrate and nitrogen source assimilation profile by using the ID 32C yeast identification system.

Use of anti-GOR testing in the screening of blood donors for hepatitis C virus infection

Sera from 12/1,155 (1%) anti-HCV-negative (Elisa) UK blood donors were found to be anti-GOR positive. None out of 12 of those sera were positive for HCV RNA by the reverse transcriptase/polymerase chain reaction (RT/PCR). In a cohort of 316 anti-HCV Elisa-positive sera, 27/57 RIBA-positive, and 1/188 RIBA-negative sera were anti-GOR positive, resulting in a sensitivity of 47% and a specificity of 99.5% for anti-GOR as a marker for RIBA-confirmed HCV infection. Four out of 71 (6%) of RIBA-indeterminate sera were anti-GOR positive. Donors with anti-GOR reactivity were more likely to have antibodies against each of the individual HCV antigens represented in the RIBA, and those antibodies were of greater intensity, when compared to the anti-GOR negative cohort. Twenty out of 36 (55.6%) of RT/PCR-positive sera were anti-GOR positive, compared to 1/7 (14.3%) of RT/PCR-negative sera (p = 0.09). The usefulness of anti-GOR testing of UK blood donors is discussed in the light of these results.

Investigation of vaccine reactions and breakdowns after feline calicivirus vaccination

The clinical and epidemiological features of feline calicivirus associated vaccine reactions and breakdowns were investigated. Twenty per cent of 123 vaccine reactions were associated with acute oral/respiratory disease alone, and 80 per cent were associated with lameness either alone or in association with other clinical signs. Feline calicivirus was isolated from oropharyngeal swabs from 69 per cent of the vaccine reaction cases. Twenty-four of 31 vaccine breakdowns were associated with acute oral/respiratory disease and only seven with lameness; the virus was isolated from 28 of the 31 breakdowns. Some of the viruses isolated from the vaccine reactions were compared with the appropriate vaccine virus in virus neutralisation tests; the majority appeared to be different from the vaccine virus and were presumably field viruses. However, some appeared more similar to the vaccine virus and the majority of these were associated with lameness after the first vaccination.

Reproducibility of the microdilution checkerboard method for antibiotic synergy

We assessed the reproducibility of the microdilution checkerboard method for measuring antibiotic synergy. Five strains of Pseudomonas aeruginosa were tested with four antibiotic combinations by using 10 replicates each. Twenty-five percent of replicate sets gave discordant classification results (i.e., a 7:3 or worse split in categorization). Determination of the individual MICs of each antibiotic alone was excellent; all 10 replicates were within 1 twofold dilution for 95% of the 80 sets of 10 replicates. The microdilution checkerboard method either should not be used or should be used with at least five replicates per determination, with > or = 80% agreement among the replicates required for classification.

Dopexamine hydrochloride maintains portal blood flow and attenuates hepatic ultrastructural changes in a porcine peritonitis model of multiple system organ failure

Fifteen anesthetised pigs (25-30 kg) were divided into three equal groups, sham, dopexamine (D) (10 micrograms/kg/min), and placebo (P). Sepsis was induced by fecal peritonitis in the D and P groups and colloid was infused to try to maintain mean arterial blood pressure (MABP) at a constant value and the hemodynamics measured at baseline and hourly for 8 hr. There was an initial increase in MABP and systemic vascular resistance (SVR) in the P group but not the dopexamine (D) group. Cardiac output (CO) in the P group showed a small decline but increased in the D group. The portal blood flow (PVF) in the P group fell with MABP but increased in the D group as MABP fell. The sham group showed normal ultrastructure and cellular integrity. Occlusion of the hepatic sinusoids was similar in the D and P groups. There was a greater area of Kupffer cells and endothelial cells in the P group, suggesting a greater inflammatory reaction than was found in the D group. Ultrastructure and mitochondrial integrity was better maintained in the D group. Dopexamine hydrochloride infusion maintained CO, increased PVF, and attenuated hepatic ultrastructural changes compared to placebo in a porcine fecal peritonitis model of multisystem organ failure.

Influence of thrombolytic therapy on the evolution of baroreflex sensitivity after myocardial infarction

Depressed baroreceptor sensitivity (BRS) has been associated with an increased risk of ventricular arrhythmias and sudden cardiac death after myocardial infarction, but the influence of thrombolytic therapy on BRS has not been examined. To determine the effect of thrombolytic therapy on the evolution of BRS after myocardial infarction, BRS was assessed at 6 days, 6 weeks, and 3 months in 76 patients, 53 (70%) of whom had received thrombolytic therapy. The mean age (57 vs 57 years), sites of infarction, and the proportion of patients taking beta-blockers (68% vs 52%) did not differ between patients who did and those who did not receive thrombolytic therapy. There was no difference in predischarge mean left ventricular ejection fractions (42% vs 46%) between the two groups of patients, but mean baseline BRS was 9.2 (0.8) msec/mm Hg in patients who were treated with thrombolysis and 5.9 (1.3) msec/mm Hg in those who were not (p = 0.03). At 6 weeks the corresponding values were 9.7 (1.1) and 11.1 (2.8) msec/mm Hg (p = 0.6) and at 3 months 9.1 (1.0) and 6.5 (1.1) msec/mm Hg (p = 0.07). At baseline 13% of patients who were treated with thrombolysis and 13% of those who were not had BRS < 3.0 msec/mm Hg, but at 3 months 9% of patients who were treated with thrombolytic agents compared with 17% of those who had BRS < 3.0 msec/mm Hg. In conclusion, early after myocardial infarction mean BRS was higher in patients treated with thrombolysis compared with nontreated patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of lindane on macroinvertebrates and periphyton in outdoor artificial streams

A system of six outdoor artificial streams (dimensions 5.0 X 0.35 X 0.25 m) was used to study the biological effects of lindane in flowing water. Lindane was continuously applied during 28 days to four of the streams while two were left as untreated controls. The nominal concentrations were 4.0, 8.0, 16.0, and 32.0 micrograms liter-1 and the mean measured concentrations of lindane in stream water over 28 days were 3.1, 5.7, 11.1, and 20.3 micrograms liter-1. Effects were observed on population densities of the freshwater shrimp Gammarus pulex, drift of G. pulex and mayflies (Baetis spp.), and on community photosynthesis. An increase in photosynthetic production of oxygen, a result of increased periphyton standing crop, followed the loss of macroinvertebrates, via drift, from the treated streams. This established a clear link between a direct effect of lindane on macroinvertebrates and an indirect effect on periphyton production. Drift and community photosynthesis were the most sensitive of the biological parameters measured and effects were detected in all treated streams. During a 28-day experiment with lower concentrations of lindane, nominally 0.25 and 1.0 micrograms liter-1, there were minor effects on the drift of Baetis spp. but only at the higher concentration. There were no detected effects on population densities or on community photosynthesis. Results from the two experiments provided a measured no observed effect concentration for lindane of 0.2 micrograms liter-1 and the threshold concentration for sustained effects on the stream communities was in the range 0.8 to 3.1 micrograms liter-1.

Canine distemper virus transcripts detected in the bone cells of dogs with metaphyseal osteopathy

Using the technique of in situ hybridisation, we have recently extended our observations that canine distemper virus (CDV) is present in the bone cells of patients with Paget's disease, and have shown that CDV is also detectable in the bone cells of dogs that are naturally infected with the virus. Since hybridisation was localised to bone cells within the metaphyses of the affected dogs, we investigated the possibility that CDV might be involved in the canine metaphyseal bone disorder, metaphyseal osteopathy. Bone samples from three cases of metaphyseal osteopathy were examined for the presence of the CDV nucleocapsid (CDV-N) gene and the measles virus nucleocapsid (MV-N) gene, using 35S-labelled sense and antisense riboprobes. As with our previous findings in Paget's disease of bone, only the antisense probe was found to hybridize to the osteoblasts and osteoclasts within the affected metaphyses. No hybridisation was seen with the CDV-N sense and MV-N probes in any of the samples tested. Bone samples were also taken from one of the cases to check for the presence of the CDV-N gene using the polymerase chain reaction (PCR). Our findings with in situ hybridisation were confirmed by PCR and subsequent Southern blotting and probing with a 32P-labelled cDNA probe. The detection of CDV RNA within the bone cells of dogs with metaphyseal osteopathy suggests that this virus may be a cause of the disease and provides further, indirect evidence that CDV might be responsible for the bony abnormalities seen in Paget's disease of bone.

Clinical comparisons of continuous venous oxygen saturation and hematocrit monitors in pediatric surgery

Continuous venous oxygen saturation and hematocrit values are important parameters in assessing patient status while on cardiopulmonary bypass. Two devices used to measure continuous venous oxygen saturation while on cardiopulmonary bypass were compared to a control. The Bentley Oxysat meter and the Medtronic MX2 Oxygen Saturation and Hematocrit System were compared to the ABL500 blood gas monitor. The continuous hematocrit readings from the MX2 system were compared to spun hematocrits. Twenty-nine pediatric patients ranging from 2.3kg-43.3kg were randomly selected. In-line optical transmission cells used were 1/4" or 3/8" depending upon the patient's blood flow requirements. A total of 163 data points were analyzed at different blood flow rates, temperatures, and hematocrits. The venous oxygen saturation values obtained from the Oxysat and the MX2 devices correlated well with the ABL500 over the entire range of blood flows, temperatures, and hematocrits. All correlation coefficients were greater than 0.89. The correlation between the MX2 device and the spun hematocrit varied with temperature ranges. The correlation coefficient tended to decrease with decreasing temperature. We conclude that these devices are important adjuncts to bypass as long as their limitations are understood.