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Biomedical subjects

R L Jones

Publications and source records attributed to R L Jones.

At least 253 records · Page 14Linked to original sources
PubMed1986

Immune response in rams experimentally infected with Brucella ovis.

Cellular as well as humoral immune responses were detected in six rams experimentally infected with Brucella ovis. Specific antibodies were detectable by enzyme-linked immunosorbent assay by day 11 after infection in all the rams. The levels of IgM antibodies and total antibodies in the serum rose until 33 and 41 days after infection respectively, then levelled off. Antigen-induced blastogenic responses by lymphocytes developed as early as five days after infection in all rams but had decreased to low levels by day 63 in most. Blastogenesis induced by phytohaemagglutinin and concanavalin A varied among infected rams and did not differ significantly (P greater than 0.05) from control rams. All rams had developed delayed-type skin hypersensitivity by day 63 after infection. One ram which did not become infected as a result of exposure had low levels of B ovis serum antibodies and a detectable antigen-induced lymphocyte blastogenic response before infection, suggesting the involvement of cell-mediated immunity in protection against B ovis.

Animals↗
PubMed1986

Regional air trapping before and after exercise in young adults with cystic fibrosis.

Much of respiratory therapy in patients with cystic fibrosis is directed toward clearing airway secretions and dilating the airways to improve ventilation to slowly equilibrating spaces. We studied nine patients with cystic fibrosis (18 to 28 years old) who had mild to severe airway obstruction to determine whether ventilation to regions containing slow spaces was influenced by a period of exercise. Regional ventilation was assessed by measuring the trapped-air index (TAI) before and at least (1/2) hour after bicycle exercise. On the average, the TAI was highest in the apices and lowest in the lung bases. The apical TAI correlated significantly with the overall amount of trapped air and the forced expiratory volume in one second, indicating that abnormalities in the apices have a pronounced influence on overall lung function. For the patients with moderate or severe airway obstruction, the mean TAI decreased after exercise in the upper regions where it was abnormally high before exercise. The results suggest that slow spaces exist in the apices of all patients with cystic fibrosis who have airway obstruction and that a period of exercise improves tidal ventilation in the apices of patients with moderate or severe airway obstruction.

Adolescent↗
PubMed1986

Immunohistochemical staining patterns of canine eyes affected with chronic superficial keratitis.

Fourteen limbal biopsy specimens from 11 dogs with chronic superficial keratitis (CSK) were examined histologically and immunohistochemically. Ten of the 14 specimens had corneal epithelial hyperplasia and/or atrophy. Eleven of the 14 specimens had thickened epithelial basement membranes. Each specimen had cellular infiltration and lamellar disruption of the stroma. An avidin-biotin immunoperoxidase complex stain was used to detect immunoglobulin (Ig) deposition. Twelve of the 14 specimens stained positive for Ig. The staining pattern was consistent and characterized by diffuse deposition of stain in the superficial conjunctival stroma near the limbus. Four of the 12 Ig-positive specimens also stained positive in the superficial corneal stroma with 1 of these 4 also staining positive along the epithelial cell basement membrane. The diffuse pattern of stain deposition and the absence of staining of specific epithelial structures indicated that CSK is not a classical autoimmune disease similar to any disease in the pemphigus group or similar to systemic lupus erythematosus. Although the results may implicate CSK as an immune-mediated disease, nonspecific factors could not be ruled out.

Animals↗
PubMed1985

Proton NMR investigation of the nucleosome core particle: evidence for regions of altered hydrogen bonding.

Novel 1H nuclear magnetic resonance (NMR) resonances, arising from exchangeable protons and centered at approximately 11.2 and 10.1 parts per million (ppm), have been observed in the low-field spectrum (10-15 ppm) of the chicken erythrocyte core particle [145 +/- 2 base pairs (bp)]. These peaks are located upfield from the normal adenine-thymine (A-T) and guanine-cytosine (G-C) imino peaks characteristic of B-form deoxyribonucleic acid (DNA) and are not observed in free DNA under identical conditions. The appearance of the new peaks is ionic strength dependent and temperature-reversible below 75 degrees C. At 25 degrees C, the upfield peak area represents 5% of the DNA base pairs (7 bp), while between 45 and 55 degrees C, the area increases to 18%, affecting approximately 25 bp. Area increases in the upfield resonances result in a complementary decrease in the A-T and G-C imino peaks found between 12 and 14 ppm. We believe these novel proton signals represent a histone-induced DNA conformational change which involves localized alteration of base pairing in the core particle.

Animals↗
PubMed1985

Long term effects of cryosurgery on cutaneous sensation.

In a study of the time course and nature of the sensory loss after cryosurgery the forearms of nine normal subjects were treated with liquid nitrogen using freeze times currently employed in clinical practice in Britain. Ability to appreciate touch, pinprick, and cold in the treated areas was tested at regular intervals and biopsy samples taken to investigate the pathogenesis. Appreciation of all three modalities of sensation was initially reduced in all nine subjects for all freeze times, yet complete recovery occurred in the seven patients completing follow up. This recovery, however, took up to one and a half years for the longest freeze, with even a 10 second freeze taking up to 10 months. Patients may be reassured that sensory loss after cryosurgery for up to two periods of 30 seconds will almost certainly recover, though it may take up to 18 months to do so.

Adult↗
PubMed1985

Mechanism of the inhibition of platelet aggregation produced by prostaglandin F2 alpha.

The inhibition of human platelet aggregation produced by PGF2 alpha is not specific for thromboxane A2 mimetics. Aggregation waves induced by PAF and thrombin are also inhibited by PGF2 alpha (8 microM); ADP is unaffected. These effects are still seen in platelets from aspirin-treated donors and platelets desensitized to thromboxane-like agonists (e.g. 11,9-epoxymethano PGH2). In contrast the thromboxane receptor antagonist EP 045 (up to 20 microM) had no effect on primary aggregation induced by PAF, thrombin and ADP. We have previously shown that EP 045 (IC50 = 0.5 microM), but not PGF2 alpha (28 microM), displaces the specific binding of [3H] 9,11-epoxymethano PGH2 to washed human platelets. PGF2 alpha produces small increases in cAMP levels, and both this effect and the anti-aggregation are diminished by the adenyl cyclase inhibitor SQ 22536. The rise in cAMP induced by PGF2 alpha is inhibited to a greater extent by the presence of ADP than by thrombin, PAF or a thromboxane mimetic. The ability of aggregating agents to inhibit this increase correlates inversely with their sensitivity to inhibition by PGF2 alpha. We suggest that the very weak effect of PGF2 alpha on cyclic AMP production is sufficient to account for its inhibitory activity, and it is unlikely to be a competitive antagonist at the platelet thromboxane receptor as suggested by others.

Adenosine Diphosphate↗
PubMed1985

Effect of the thromboxane receptor antagonist EP 092 on endotoxin shock in the sheep.

The thromboxane receptor antagonist EP 092 inhibits the acute pulmonary vascular response to E. coli endotoxin in the anaesthetized, closed-chest sheep. The increase in the TXB2 level in arterial blood was not suppressed by EP 092. Intravenous infusion of the thromboxane mimetic 11,9-epoxymethano PGH2, but not PGF2 alpha, raises pulmonary artery pressure and lowers arterial pO2 similar to the endotoxin. Isolated strips of lobar pulmonary veins but not lobar arteries are contracted by low concentrations of 11,9-epoxymethano PGH2 - the effects are potently inhibited by EP 092.

Animals↗
PubMed1985

Pulmonary vascular response to high-frequency oscillatory ventilation in dogs: lack of effect of indomethacin.

The role of prostaglandins (PG) in the pulmonary hypertension associated with high-frequency oscillatory ventilation (HFOV) was investigated in 7 pentobarbital-anesthetized dogs. The magnitude and time course of the mean pulmonary artery pressure (PAP) changes induced by HFOV (20 Hz) was quantified before and after PG-production blockade with 15 mg/kg indomethacin (INDO) i.v. It was found that HFOV before INDO induced a 27.2 +/- 5.6% increase in PAP above baseline and a 30.0 +/- 7.2% one hour after INDO administration. This difference was not statistically significant. The time course of the PAP changes induced by HFOV before and after blocking PG-production by INDO were also similar. Mean airway pressure, PaO2 and PaCO2 during HFOV, before and after INDO were not statistically different. It is concluded that the acute increase in PAP induced by HFOV is not due to PG release.

Animals↗
PubMed1985

A glycolipid antigen specific to Mycobacterium paratuberculosis: structure and antigenicity.

Mycobacterium paratuberculosis (National Animal Disease Center strain 18 and American Type Culture Collection strain 19698), the causative agent of Johne Disease (bovine paratuberculosis), contains a major immunoreactive glycopeptidolipid (polar GPL-I) that has been isolated and characterized. (formula; see text) Thus, the glycolipid antigen belongs to the polar mycoside C glycopeptidolipid family present in other mycobacterial species. The distal 2,3-di-O-methyl-alpha-L-fucopyranosyl-(1----3)-alpha-L-rhamnopyranosi de unit, the obvious antigen determinant, appears to be characteristic of M. paratuberculosis. The glycolipid can be recognized readily in isolates of M. paratuberculosis by TLC and its presence may be used as a characteristic marker of the infectious agent. The polar glycopeptidolipid was highly reactive in ELISA against serum from an animal hyperimmunized with M. paratuberculosis strain 18, indicating its basic immunogenicity.

Amino Acid Sequence↗
PubMed1985

Effect of nutrition on broiler carcase composition: influence of dietary energy content in the starter and finisher phases.

Three isonitrogenous starter (230 g/kg) and three finisher diets (200 g/kg) were formulated to contain 10.78, 12.78 and 14.78 MJ AME/kg and fed to 1512 male and female broilers such that there were 9 treatment combinations. Birds fed the low-energy starter diet were significantly lighter (P less than 0.05) and their carcases contained proportionally less abdominal fat and total carcase fat at 24 d of age. This effect remained until 49 d of age irrespective of the finisher diet fed. The energy content of the finisher diet had no significant effect on bodyweight but the proportion of abdominal fat and total carcase fat deposited was lower for birds fed the low-energy finisher.

Adipose Tissue↗
PubMed1985

Alveolar pressures and lung volumes during high-frequency oscillatory ventilation in dogs.

A constant-volume plethysmograph was used to measure functional residual capacity (FRC) in anesthetized dogs before, during, and after high-frequency oscillatory ventilation (HFO). The phrenic nerves were electrically stimulated to provide the necessary respiratory effort. In addition to FRC, mean alveolar pressure (PA) was obtained from the pressure axis of the static pressure/volume (P/V) curve at FRC. In eight dogs, the first min of HFO at 22 ml, 20 Hz, and a 4 L/min bias flow of air increased FRC by an average of 63.6% above the apneic value, where it remained for the subsequent 15 min. PA values were significantly higher than mean airway pressures (Paw) measured in the endotracheal tube, indicating higher pressure in the terminal lung units. In five other dogs, FRC, Paw, and mean pleural pressure increased as HFO was increased from 15 to 30 Hz with 1 and 4 L/min bias flows of air. We speculate that these increases may account for both the impairment of cardiovascular function and improvements in oxygen tensions often seen with HFO.

Animals↗
PubMed1985

Control of alpha-amylase mRNA accumulation by gibberellic Acid and calcium in barley aleurone layers.

Pulse-labeling of barley (Hordeum vulgare L. cv Himalaya) aleurone layers incubated for 13 hours in 2.5 micromolar gibberellic acid (GA(3)) with or without 5 millimolar CaCl(2) shows that alpha-amylase isozymes 3 and 4 are not synthesized in vivo in the absence of Ca(2+). A cDNA clone for alpha-amylase was isolated and used to measure alpha-amylase mRNA levels in aleurone layers incubated in the presence and absence of Ca(2+). No difference was observed in alpha-amylase mRNA levels between layers incubated for 12 hours in 2.5 micromolar GA(3) with 5 millimolar CaCl(2) and layers incubated in GA(3) alone. RNA isolated from layers incubated for 12 hours in GA(3) with and without Ca(2+) was translated in vitro and was found to produce the same complement of translation products regardless of the presence of Ca(2+) in the incubation medium. Immunoprecipitation of translation products showed that the RNA for alpha-amylase synthesized in Ca(2+)-deprived aleurone layers was translatable. Ca(2+) is required for the synthesis of alpha-amylase isozymes 3 and 4 at a step after mRNA accumulation and processing.

Journal Article↗
PubMed1985

Competitive antagonism at thromboxane receptors in human platelets.

The inhibitory effects of three prostanoid analogues, EP 045, EP 092 and pinane thromboxane A2 (PTA2), on the aggregation of human platelets in vitro have been investigated. In diluted platelet-rich plasma (PRP), EP 045 (20 microM) and EP 092 (1 microM) completely inhibited irreversible aggregation responses to thromboxane A2 (TXA2), prostaglandin H2 (PGH2) and five chemically stable thromboxane mimetics, including 11,9-epoxymethano-PGH2 and 9,11-azo-PGH2. Reversible aggregation produced by the prostanoid analogue, CTA2, was also inhibited. The block of the stable agonist action was surmountable. In plasma-free platelet suspensions EP 045 and EP 092 were more potent antagonists. Schild analysis indicated a competitive type of antagonism for EP 045 (affinity constant of 1.1 X 10(7) M-1); the nature of the EP 092 block is not clear. Primary aggregation waves induced by ADP, platelet activating factor (Paf) and adrenaline were unaffected by EP 045 and EP 092, whereas the corresponding second phases of aggregation were suppressed. Aggregation and 5-hydroxytryptamine (5-HT) release induced by either PGH2 or 11,9-epoxymethano-PGH2 were inhibited in a parallel manner by EP 045. Inhibition of thromboxane biosynthesis is not involved in these effects. EP 045 and EP 092 did not raise adenosine 3':5'-cyclic monophosphate (cyclic AMP) levels in the platelet suspensions. In plasma-free platelet suspensions PTA2 produced a shape change response which could be blocked by EP 045. PTA2, therefore, has a thromboxane-like agonist action. The block of the aggregatory action of 11,9-epoxymethano-PGH2 by PTA2 appears to be mainly due to competition at the thromboxane receptor. However, PTA2 produced a slight rise in cyclic AMP levels; this could be due to a very weak stimulant action on either PGI2 or PGD2 receptors present in the human platelet. Functional antagonism by PTA2 may therefore augment its thromboxane receptor blocking activity. The results are discussed in terms of (a) the specificity of antagonism produced by EP 045, EP 092 and PTA2, (b) the validity of affinity constant determinations for receptor antagonists when aggregation is the biological response, and (c) the characteristics of the human platelet thromboxane receptor in comparison with those of thromboxane receptors in smooth muscle.

Alprostadil↗
PubMed1985

Evaluation of the RapID-ANA system for identification of anaerobic bacteria of veterinary origin.

This study evaluated the ability of the RapID-ANA system (Innovative Diagnostic Systems, Inc., Atlanta, Ga.) to accurately identify a spectrum of freshly isolated veterinary anaerobes. A total of 183 isolates were tested and included 7 Actinomyces spp., 53 Bacteroides spp., 32 Clostridium spp., 2 Eubacterium spp., 65 Fusobacterium spp., 1 Peptococcus spp., 22 Peptostreptococcus spp., and 1 Propionibacterium spp. All isolates were initially identified by conventional biochemical testing and gas-liquid chromatography of short-chain fatty acid metabolites. Additional tests were performed as required by the RapID-ANA system. Of these isolates, 81.4% were correctly identified to the genus level, including 59.6% to the species level, 14.2% were incorrectly identified at the genus level, and 4.4% were not identified. Initially, 20.2% of the strains were not identified because the microcodes were not in the code book. The majority of the incorrect identifications were caused by the misidentification of Fusobacterium spp. as Bacteroides spp. Errors also occurred when veterinary anaerobes not included in the data base were assigned an identification from the existing data base. The RapID-ANA system appears to be a promising new method for rapid identification of veterinary anaerobes; however, further evaluation with an extended data base is needed before the system can accurately identify all clinically significant anaerobes.

Animals↗
PubMed1985

Collateral ventilation during high-frequency oscillation in dogs.

Mechanics of collateral channels during high-frequency oscillatory ventilation (HFOV) were assessed in eight anesthetized dogs, using a modification of Hilpert's technique. Base-line functional residual capacity was measured with a body plethysmograph, with inspiratory efforts induced by phrenic nerve stimulation. The resistance (Rcoll) and time constant (Tcoll) of collateral channels at five lung volumes were measured during HFOV and positive end-expiratory pressure (PEEP). Rcoll and Tcoll were significantly higher during HFOV (P less than 0.001); the differences did not correlate with resting lung volumes. The calculated static compliance of the wedged segment was similar during HFOV and PEEP (P greater than 0.005). Mean pressures measured in small airways during HFOV corresponded to the midline between the inflation and deflation limbs of the static pressure-volume curves, indicating similar pressure-volume characteristics of the respiratory system during HFOV and static conditions. We conclude that HFOV increases resistance to gas flow through collateral channels but that this pathway may still be important in gas exchange.

Animals↗