Search PubMed⌕ Search

Biomedical subjects

D Jones

Publications and source records attributed to D Jones.

At least 523 records · Page 29Linked to original sources
PubMed1991

Immunizing efficacy of aromatic-dependent Salmonella dublin in mice and calves.

Mice immunized with an aromatic-dependent (aro-) S. dublin strain CS101 by either the intraperitoneal (i.p.) or oral route, were protected against oral challenge with a virulent S. dublin strain CS90, the degree of protection being the greatest when mice had received 3 immunizing doses at weekly intervals. Mice immunized with an aromatic-dependent (aro-) S. typhimurium strain CS332 by the i.p. or oral routes were protected against challenge with virulent S. dublin strain CS90 at 1 or 2 weeks but not at 3 or 4 weeks post-immunization. Mice immunized with 1 dose of aro- S. dublin strain CS101 by the i.p. route developed low levels of lipopolysaccharide (LPS) and flagellin-specific antibody but no delayed-type hypersensitivity (DTH) whereas those immunized with 2 or 3 doses developed significantly higher antibody titres and DTH. In contrast, mice immunized by the oral route developed neither significant antibody response nor DTH. The aro- S. dublin strain CS101 could not be detected beyond day 28 post-inoculation in visceral organs including liver, spleen, mesentery, small intestine, caecum or large intestine of mice inoculated by the i.p. route or in mice inoculated by the oral route with the exception of day 42 post-inoculation. Challenge of mice previously immunized with 3 doses of the aro- S. dublin strain CS101 by the i.p. or oral route with virulent S. dublin strain CS90 resulted in their rapid clearance from the above visceral organs. Calves immunized with the aro- S. dublin strain CS101 by either the intramuscular (i.m.) or oral routes were significantly protected against oral challenge with virulent S. dublin strain CS90. In contrast to the observations in mice, somatic (O) and flagellar (H) antibody titres of calves immunized by either route were negligible as were anti-LPS antibody titres. However, flagellin-specific antibody titres were higher in calves immunized by the i.m. than the oral route. These results indicate that the protection observed in immunized mice or calves against oral challenge with virulent S. dublin was unlikely to have been mediated by humoral salmonella-specific immune mechanism(s).

Administration, Oral↗
PubMed1991

Culture confirmation of cytomegalovirus and herpes simplex virus by direct enzyme-labeled DNA probes and in situ hybridization.

Using probes consisting of horseradish peroxidase (HRP) directly attached to DNA, scrapings or trypsinized cells from 217 adequate clinical samples were cultured and analyzed in 3 blind studies by in situ hybridization for the presence of cytomegalovirus (CMV) and herpes simplex virus (HSV). Sixty samples were judged inadequate due to insufficient cell numbers; however, this problem was significantly decreased during the course of the study. One hundred and eighteen samples were found positive and 70 samples were found negative for CMV. Scrapings of cultured cells from 29 clinical samples revealed 9 samples which were positive and 20 samples which were negative for HSV. Forty-two additional samples, containing either uninfected cells or cells infected with various strains of CMV, were analyzed for the ability of the HRP-DNA CMV probe to detect such isolates. Twenty samples were positive and 22 negative for CMV. No false-negatives or false-positives were observed for either CMV or HSV. In addition to the specificity noted above neither the CMV nor the HSV DNA probe hybridized to potential contaminants found in clinical specimens.

Cell Line↗
PubMed1991

Practical 3-D radiotherapy planning of brain tumors.

In postoperative radiotherapy of brain tumors it is usually the case that preoperative imaging studies, either CT or MRI, were performed outside of the purview of the radiation therapy department. Thus the target volume is defined in an imaging study that does not lend itself readily for entry to a 3-D treatment planning system. A method is described that adjusts the patient structure defined by scan data to an appropriate position for radiotherapy. Software tools that are simple to use have been incorporated in a 3-D treatment planning program that allows oblique treatment planes to be defined. The program provides beam's-eye-view plots of the fields that are used to overlay simulation films and will automatically describe a field blocking outline that provides a prescribed margin on the target volume or other structures that have been defined. Finally, dose calculations in arbitrary planes through the head are made and isodose plots produced.

Brain Neoplasms↗
PubMed1991

Effect of growth temperature on virulence of strains of Listeria monocytogenes in the mouse: evidence for a dose dependence.

Growth of Listeria monocytogenes at 4 degrees C significantly increased its virulence for mice by the intravenous route and the effect was dose-dependent. Virulence was apparent only at a dose of about or above 10(4) viable listerias. At slightly lower doses of about 10(3), no such effect was observed. Growth at 4 degrees C did not increase the virulence of the strains for mice by oral-gastric challenge when given at doses of approximately 10(10).

Animals↗
PubMed1991

Screening for diabetic retinopathy.

There is a need for greater educational emphasis, both at undergraduate and postgraduate level, on the detection of diabetic eye disease, in particular diabetic retinopathy. The early diagnosis of the sight-threatening lesions of proliferative retinopathy and maculopathy is a prerequisite for the prevention or reduction of the visual loss and blindness associated with this diabetic complication. It is also essential that patients are aware that diabetes can result in visual loss due to diabetic retinopathy. Patients should understand that diabetic retinopathy may be present without ophthalmic or diabetic symptoms and that its incidence increases with duration of diabetes, poor diabetes control, and hypertension. They must also be aware that, if detected early, retinopathy can be treated successfully and vision preserved. Early detection depends on regular eye examination involving both visual acuity assessment and ophthalmoscopy through dilated pupils by experienced personnel. A comprehensive programme of screening followed by prompt and adequate treatment would made a significant contribution to eradicating diabetic retinopathy as a cause of blindness.

Adult↗
PubMed1991

Measurement of haematological indices of chronic rheumatic disease with two newer generation automated systems, the H1 and H6000 (Technicon).

Two automated counters, the H1 (Technicon) and the H6000 (Technicon), which count 10,000 cells per sample, were compared and used to examine the clinical relevance of the additional haematological information now provided to the rheumatologist in three groups of patients--38 with rheumatoid arthritis (RA), 41 with ankylosing spondylitis (AS), and 35 with systemic lupus erythematosus (SLE). The two machines agreed in their estimations of the main indices (haemoglobin, red blood cell count, and white blood cell count), but estimations of platelet count and volume were significantly lower on the H6000 machine, as were mean cell haemoglobin and monocyte count, whereas packed cell volume and red cell distribution width were higher. As expected, both machines identified pancytopenia among the group with SLE, while low haemoglobin and high platelet count were found particularly among patients with RA and AS respectively. Additional information available from these counters showed marked variability in red cell size in SLE, and also of haemoglobin content, which is only measured on the newer H1 machine. Flags for microcythaemia, anisochromasis, and white cell noise (usually due to nucleated red cells) were all more common in SLE. Interpretation of results was complicated by the inevitable difference in age and sex distribution among the disease groups, and identification of active disease was also limited by the effect of drugs. In conclusion, the increasingly widespread use of automated counters as part of the routine haematological service may provide the rheumatologist with useful information, but, as always, care should be taken in the interpretation of indices in patients receiving non-steroidal or second line agents, and also in extrapolating results from one machine to another when they are updated or when patients are monitored at more than one centre.

Adolescent↗
PubMed1991

Direct measurement of skeletal muscle fatigue in patients with chronic heart failure.

Skeletal muscle function was measured as force production and fatigue in both the quadriceps (a large locomotive muscle) and adductor pollicis (a small intrinsic hand muscle) in five healthy volunteers, five patients with mild chronic heart failure, and five patients with severe chronic heart failure. The quadriceps of patients with chronic heart failure had a reduced muscle cross sectional area, a reduced maximum isometric force production, and an increased tendency to fatigue. Isometric force production and fatigue of the adductor pollicis, however, were not significantly different between the three groups under control conditions. But during circulatory occlusion fatigue in the adductor pollicis increased more in the patients with severe chronic heart failure. These differing findings in quadriceps and adductor pollicis suggest that skeletal muscle atrophy and reduced isometric force production are not a necessary consequence of chronic heart failure per se, because they were only present in the large locomotive muscle. The normal values for muscle fatigue observed in adductor pollicis in patients with chronic heart failure imply that skeletal muscle blood flow must increase normally during muscle activation when only a small muscle mass is used. These results are not compatible with the concept of a generalised impairment of normal vasodilatation within active skeletal muscle. In contrast, activation of a large muscle, such as quadriceps, results in the rapid onset of fatigue in patients with severe chronic heart failure. This fatigue may be related to the inability of the cardiovascular system to provide the required blood flow for the activation of a large muscle mass. The finding of a relatively greater increase in fatigue of adductor pollicis during circulatory occlusion in patients with severe chronic heart failure supports the hypnosis of an intrinsic abnormality of skeletal muscle in these patients.

Adult↗
PubMed1991

Expression of MHC class II antigens by conjunctival epithelial cells in trachoma: implications concerning the pathogenesis of blinding disease.

In an attempt to understand the pathogenesis of corneal changes and conjunctival scarring in trachoma, which are responsible for blindness in some 7 million people worldwide, the surface expression of major histocompatibility complex class II antigens on conjunctival epithelial cells was sought in patients with different clinical features of the disease. Class II expression was significantly associated with active (inflammatory) trachoma, but an independent association with corneal pannus or conjunctival scarring could not be shown. Longitudinal data suggest that class II expression may antedate clinically active disease and persist after it has resolved.

Adolescent↗
PubMed1991

6-(substituted methylene)penems, potent broad spectrum inhibitors of bacterial beta-lactamase. III. Structure-activity relationships of the 5-membered heterocyclic derivatives.

Sodium (5RS)-Z-6-(heterocyclylmethylene)penem-3-carboxylates (2) are a series of extremely potent inhibitors of bacterial beta-lactamases. A variety of 5-membered heteroaromatic derivatives have been prepared and structure-activity studies reveal a preferred substituent orientation. One of these derivatives, the 1-methyl-1,2,3-triazolyl compound (5m) is a more potent synergist of amoxycillin than clavulanic acid, sulbactam or tazobactam.

Amoxicillin↗
PubMed1991

Clinical experiences with a single use Y bagless CAPD system applying a quick disconnect clamp for external occlusion.

The Single Use Y set is a disposable CAPD system that incorporates the use of a Quick Disconnect Clamp (QDC) for external occlusion. The system is designed using two types of twist lock connectology. The twist lock bag connector located at the distal end of the set is designed with a flange that provides a safety shelf for proper hand position during bag connection. The proximal patient connector on the Y set is a twist lock design requiring placement of povidone-iodine in the disinfectant chamber of the connector prior to patient connection. The Single Use Y is discarded after use.

Disposable Equipment↗