Search PubMed⌕ Search

Biomedical subjects

R B Ashman

Publications and source records attributed to R B Ashman.

143 records · Page 8Linked to original sources
PubMed1977

Human polymorphonuclear leucocytes as mediators of antibody-dependent cellular cytotoxicity to herpes simplex virus-infected cells.

Human polymorphonuclear leucocytes (PML) were able to mediate antibody-dependent cellular cytotoxicity (ADCC) against target cells acutely infected with type 1 Herpes simplex virus. The reaction mediated by PML occurred more slowly and required higher concentrations of immune serum than that mediated by human mononuclear cells (MC). At the same ratio of effector cells to target cells, PML-mediated ADCC was less than MC-mediated ADCC. The observed relationship between the number of effector cells added, and the number of target cells lysed, showed that cytolysis mediated by both PML and MC was consistent with 'one hit' probability predictions. This suggested that target cell death resulted from an interaction with a single effector cell. The calculated frequency of effector cells in PML preparation was similar to that in MC, approximately 3-5%. Preliminary examination of the nature of the effector cells suggested that they did not comprise a morphologically distinct subclass of PML. These experiments demonstrate a possible new role for PML in host defence against viral infections.

Antibodies, Viral↗
PubMed1977

Enhancement of human lymphocyte responses to phytomitogens in vitro by incubation at elevated temperatures.

Incubation of human lymphocytes with PHA or Con A at 39 degrees C for 3 days caused a consistent, statistically significant, increase in [3H]thymidine uptake, compared with cultures incubated at 37 degrees C. The responses were also significantly increased after 2 days of incubation, suggesting that hyperthermia not only enhanced, but also caused an earlier onset of the mitogen response.

Cells, Cultured↗
PubMed1977

Rosette formation and inhibition in cervical dysplasia and carcinoma in situ.

Total and early rosettes and rosette inhibition were measured in patients with cervical dysplasia and carcinoma in situ. Both total and early rosettes were significantly depressed in patients with carcinoma in situ; early rosettes were also significantly lower than were controls in women with severe dysplasia. Rosette inhibition titers were increased in most patients with moderate dysplasia and in all patients with either severe dysplasia or carcinoma in situ. Thus, the Rosette inhivition test may be useful in detecting, in a precancerous state, patients at risk for cancer.

Adult↗
PubMed1976

Immunology of herpes simplex virus infection: relevance to herpes simplex virus vaccines and cervical cancer.

The immunology of herpes simplex infections has been reviewed, particularly in relation to potential herpes simplex virus (HSV) vaccines, and to the association between HSV and cervical cancer. Relevant data from humans, experimental animals, and in vitro systems implicate both specific immune mechanisms and nonspecific factors in the course of HSV infections. There appear to be complex interactions between the various populations of mononuclear cells, marcrophages, and lymphokines or other humoral factors. It is not yet possible, however, to pinpoint the crucial factors determining the different manifestations of the viral infection (primary infection, endogenous recurrence, or exogenous reinfection) in the various human hosts, although genetic factors may be important. While numerous animal models of HSV infection are available for the evaluation of HSV vaccines, models of HSV-induced cervical cancer require further exploration.

Age Factors↗
PubMed1976

The in vitro response to phytomitogens of marsupial leukocytes.

Leukocytes from two macropod marsupials, the quokka (Setonix brachyuras) and the tammar (Macropus eugenii) were separated from whole blood by dextran sedimentation and established in culture with either phytohemagglutinin-P, concanavalin A, or pokeweed mitogen. The leukocyte response to each mitogen, as measured by the incorporation of tritiated thymidine into DNA, was similar to that described in other experimental systems. These results suggest that the functional elements of the cellular immune response in marsupials may have evolved along very similar lines to those in the eutherian mammals.

Animals↗
PubMed1975

A rapid method for skin grafting in germfree rats.

A rapid method for skin grafting in germfree rats was developed. Six mm grafts are punched out on the tails of host and donor rats, grafts exchanged, oriented, and bound in place with non-allergic tape. Autografts healed within 5 da; first-set allografts between strains were usually rejected within 10 da. This technic provides a simple method for the assessment of skin graft responses in the germfree environment.

Animals↗
PubMed1975

Development of lymphoid tissue in a marsupial, Setonix brachyurus (quokka).

The development of the lymphoid tissues in a macropod marsupial is described. The liver is the only functional haemopoietic tissue at birth. Large lymphocytes first appear in the cervical thymus at 2 days, and in the thoracic thymus at 4 days after birth. Small lymphocytes appear 1-2 days later. The histological development of the two glands is similar, but the thoracic thymus develops much more slowly than the cervical. The appearance of Hassall's corpuscles in both thymus glands correlates with the onset of humoral immune responses in this animal. Lymph nodes first appear as aggregates of lymphocytes around the lymphatic vessels at 5 days, differentiate into cortex and medulla at about 14 days, but do not develop germinal centres until about 90 days. Small lymphocytes are not observed in the spleen until the 2nd week, and reactive centres do not appear until after 90 days of pouch life. Peyer's patches are not found until 60 days of age. Large lymphocytes are seen in the bone marrow at 14 days, but small lymphocytes are not found until the 1st month. Although the sequence of lymphoid development is similar to that seen in other animals, the rapidly with which it becomes functional suggests that it is an adaptive response to early contact with environment pathogens.

Age Factors↗
PubMedDate not supplied

Oral candidosis.

Explore the source record for details and available documents.

Candidiasis, Oral↗
PubMedDate not supplied

Three-dimensional computer analysis of complex acetabular insufficiency.

Fourteen patients with acetabular dysplasia were studied by using three-dimensional computed tomography (CT) reconstructions before pelvic osteotomies. Computer manipulation of the data allowed a preoperative visual assessment of acetabular shape, assessment of potential congruency between the femoral head and acetabulum by using a mathematical best-fit sphere, and measurement of surface contact distances that depict joint coverage and relate to concentration of weight-bearing forces. Preoperative evaluation of the three-dimensional images for these 14 patients allowed improved understanding of their abnormal anatomy and better surgical planning.

Acetabulum↗
PubMedDate not supplied

In vivo evaluation of intramedullary interlocking nail fixation of transverse femoral osteotomies in foals.

OBJECTIVE: To evaluate an intramedullary interlocking nail for stabilization of transverse femoral osteotomies in foals. STUDY DESIGN: A transverse osteotomy and restabilization with an intramedullary interlocking nail was performed on the right femur in three foals and the left femur in three foals. ANIMALS: Six foals weighing 149 to 207 kg. METHODS: The femur was destabilized with a transverse middiaphyseal osteotomy and repaired with a 0.5-in (12.7 mm) interlocking nail. The implanted femurs were radiographed monthly until completion of the study 6 months after surgery. At the completion of the study, all foals were observed for evidence of lameness, gluteal thickness was determined by ultrasonographic measurement, and a necropsy was performed. RESULTS: Healing was satisfactory in all foals. Five of the six had osseous bridging of the osteotomy apparent radiographically by 3 to 4 months. The sixth foal had postoperative infection but was healed radiographically in 5 months. There was a mean decrease in gluteal muscle thickness of 6.6 mm (P = .04) in the operated limb of the five foals that healed without complication. Two foals were lame at the completion of the project; one foal with varus deformities of the contralateral limb was mechanically lame, and another was grade 2/5 lame on the operated limb. On necropsy, there was circumferential enlargement of the diaphysis of all operated limbs with the majority of the callus at the cranial and medial aspects of the cortex. All nails were solid within the medullary cavity. CONCLUSIONS: The intramedullary interlocking nail provided adequate stabilization for repair of the transverse osteotomy. CLINICAL RELEVANCE: Further investigation is warranted before use for stabilization of spontaneously occurring fracture configurations.

Animals↗
PubMedDate not supplied

Macrophages: current views on their differentiation, structure, and function.

Macrophages are large mononuclear phagocytes that represent the major differentiated elements of the mononuclear phagocytic system. They arise from distinct progenitors in the bone marrow, and their immediate precursors, the monocytes, emigrate from the vascular compartment into many tissues and organs where they develop into mature macrophages. The latter display diverse morphological and functional characteristics, depending on the environmental stimuli that they receive. This phenotypic heterogeneity is, therefore, the final consequence of a series of down-regulation of some cellular processes and the up-regulation of others. The kinetics of the production of macrophages and their participation in various physiological and pathological phenomena is the subject of this review.

Animals↗
PubMedDate not supplied

Increased tissue resistance in the nude mouse against Candida albicans without altering strain-dependent differences in susceptibility.

Strain differences in tissue responses to infection with Candida albicans were examined in nude mice having susceptible (CBA/CaH) and resistant (BALB/c) parentage. Homozygous (nu/nu) mice of both strains were more resistant to systemic infection with C. albicans than heterozygous (nul+) littermates as indicated by a reduction in both the severity of tissue damage and colony counts in the brain and kidney. However, the tissue lesions in nu/nu CBA/CaH mice were markedly more severe than those in nu/nu mice with the BALB/c background. This pattern was reflected in the greater fungal burden in the CBA/CaH strain. Analysis of cDNA from infected tissues using a competitive polymerase chain reaction excluded interferon-gamma (IFN-gamma), tumour necrosis factor-alpha (TNF-alpha), and interleukin 6 (IL-6) as mediators of the enhanced resistance of the nude mice. The results confirm that the different patterns of lesion severity in BALB/c and CBA/CaH mice do not involve T lymphocyte-mediated pathology, and are consistent with the hypothesis that strain-dependent tissue damage is not dependent on the effector function of macrophages or their precursors.

Animals↗