Search PubMed⌕ Search

Biomedical subjects

M A Ritter

Publications and source records attributed to M A Ritter.

17 recordsLinked to original sources
PubMed1979

B-cell precursors in early chicken embryos.

The ontogeny of B-cell precursors in chicken embryos from day 3 of incubation onwards has been studied. Purified antibodies to chicken Ig L, gamma, mu, alpha chains were used in a sensitive indirect immunofluorescence assayed on fixed cell smears and wax-embedded tissue sections; the location and morphology of immunoglobulin positive (Ig+) cells were determined either in phase contrast or after histological staining. Lymphoid cells containing small amounts of cytoplasmic immunoglobulin were found in 3 day and older embryonic yolk sac, 11 and 12 day blood, 11, 12 and 13 day bursal mesenchyme. cIg+ large basophilic cells were first seen in 14 day bursal follicles. It is concluded that cells enter the embryonic bursa at different developmental stages: some appear to be uncommitted stem cells, whilst others have already commenced B-cell maturation in an extra-bursal site.

Animals↗
PubMed1979

A microbiological in-use comparison of surgical hand-washing agents.

Seven different surgical hand-scrub agents (one triclosan compound, two hexachlorophene compounds, and four iodophors) were evaluated under in-use conditions by five persons for efficacy in degerming the hands and forearms prior to performing a total of 215 total hip arthroplasties. With all of the compounds tested there was a significant reduction (p less than or equal to 0.001) of indigenous skin microflora from prescrub levels at both the post-scrub and postoperative points. The two hexachlorophene compounds in general revealed a bacteriostatic effect whereas the triclosan compound and the four iodophors did not. A hexachlorophene compound applied as a foam demonstrated excellent bacteriocidal and bacteriostatic action, was less time-consuming and easier to use than compounds applied as scrubs, and did not alter a low (0.47 per cent) in-use infection rate over a period of three years.

Anti-Infective Agents, Local↗
PubMed1979

A method for determining success following total hip replacement surgery.

The success of a total hip replacement surgery, using the hip evaluation form, was investigated in 2 groups of surgical patients which differed in terms of relative success of surgery. For the men, the group which did not respond as well to surgery had less education and were more retired individuals; this group also had more pain, less ambulation, and greater functional handicaps prior to surgery. For the women, there were no significant differences between the groups with regard to the demographic variables and the hip evaluation measures prior to surgery. The Minnesota multiphasic personality inventory administered following surgery suggests that the women who did not respond as well to surgery had more physical symptoms, anxiety, depression, and difficulties in relating to people.

Aged↗
PubMed1979

Predictive range of motion after total knee replacement.

Evaluation of 145 consecutive total knee arthroplasties pre- and postoperatively revealed that regardless of the preoperative deformity (varus, valgus, and flexion contracture), normal alignment of the knee with full extension was obtainable. The amount of flexion to be achieved postoperatively may be determined by the amount of flexion the patient had preoperatively, especially if the degree of flexion was less than 75 degrees. The prosthesis design, sex, age and diagnosis of rheumatoid arthritis were found not to correlate with postoperative motion and stability. In the osteoarthric knee, however, statistical analyses at 6 and 12 months generally showed less postoperative than preoperative range of motion.

Adult↗
PubMed1978

Embryonic mouse thymus development: stem cell entry and differentiation.

The entry and subsequent division and differentiation of blood-borne stem cells within the embryonic thymus has been studied in a system where the inflowing cells were either chromosomally or antigenically marked. H-2 positive stem cells enter the thymus within 5 days of grafting but may wait for up to 14 days before proliferating to give rise to Thy-1 positive thymocytes.

Animals↗
PubMed1978

Distribution of identity of Thy-1-bearing cells during ontogeny in rat hemopoietic and lymphoid tissues.

The distribution and identity of Thy-1+ cells during ontogeny in the rat were examined by immunofluorescent and histologic techniques, and the relative amount of Thy-1 antigen on different cell types was assessed by quantitative absorption. Thy-1+ cells were subsequently studied by dual immunofluorescence for the simultaneous expression of either T or B lymphocyte markers. The results indicate that the Thy-1 antigen is present on hemopoietic precursors and on at least some of their lymphoid (both T and B) and nonlymphoid descendants. In addition, six serologically distinct subpopulations of lymphoid cells were identified, and their position in T and B cell maturational pathways is discussed.

Animals↗
PubMed1977

Embryonic bursa development in vitro.

An in vitro culture system for embryonic chicken bursa is described, in which development, as measured by follicle formation (site of B lymphocyte development), position of large basophilic cells (stem cells), and presence of lymphocytes and cells containing cytoplasmic immunoglobulin (B cells), was comparable to that of the bursa in vivo. Using this system, preliminary studies on B lymphocyte differentiation were made. These support the view that bursal lymphocytes develop from precursors that migrate through the surrounding mesenchyme and into the follicles, but indicate that at least some of these cells may be "pre-B cells" rather than pluripotent stem cells.

Animals↗
PubMed1977

Embryonic mouse thymocyte development. Enhancing effect of corticosterone at physiological levels.

The action of corticosterone on embryonic mouse thymus development has been studied in vitro. Effects of the hormone on lymphoid differentiation varied according to the dose. 0.2-1.0 microgram/ml had an enhancing effect, resulting in an increase in the proportion of Thy-1.2 positive cells as compared with control cultures. Two to fifty micrograms per millilitre had an inhibitory effect, appearing to selectively kill small lymphocytes while leaving large and medium lymphocytes intact. At higher does these immature cells were also killed.

Animals↗
PubMed1977

Ectopic ossification after total hip arthroplasty. Predisposing factors, frequency, and effect on results.

In a statistical analysis of 398 consecutive patients with 507 total hip arthroplasties which was designed to identify factors predisposing to ectopic ossification and to determine the frequency of ossification and its effect on the results, it was found that male patients with considerable bilateral osteophytic osteoarthritis were statistically most likely to have ectopic ossification, especially if ossification had existed before arthroplasty consequent to previous surgery. Ectopic ossification which was first noted six weeks after total hip arthroplasty in 96 per cent of the cases did not change in amount thereafter, though the bone did mature. Both the range of motion of the hip and the function of the patient were affected by the ectopic bone during the first postoperative year, but after that only the range of hip motion was influenced.

Arthroplasty↗
PubMed1976

The plastic surgical adhesive drape: an evaluation of its efficacy as a microbial barrier.

A microbial evaluation was made of adhesive plastic surgical drapes and cloth surgical drapes. These studies were done both during surgery and in the laboratory. The plastic drape does not allow bacterial penetration, lateral migration does not occur, skin bacteria do not multiply under the drape within the time periods studied and the patient drapes are held in place with their use. When wet, cloth drapes showed profuse bacterial penetration. Dry cloth showed less bacterial penetration as compared to wet cloth. Lateral migration under cloth drapes was not possible to assess due to a high level of penetration. The surface of cloth showed a higher level of bacterial contamination during the surgical procedures. Deep wound cultures collected just prior to closing showed 60% contamination when cloth was used compared to 6% when plastic was employed. The micro-organisms recovered from the various sites sampled were identified. Finally, in addition to the positive aseptic benefits afforded by plastic adhesive drapes, aesthetic features such as a more delineated operative field and elimination of towel clips make this product a useful adjunct to the surgeon's armamentarium.

Air Microbiology↗
PubMed1975

Serum protein analysis following implantation of methyl methacrylate in rats.

Thirty-six Sprague-Dawley white rats were implanted with methyl methacrylate and bone wax in a 1:1 ratio. At periods of 1, 3, 5, 7, 10 and 14 days-post-implantation arterial blood samples were drawn and the serum protein separated electrophoretically. A significant depression in the alpha 1 and alpha 2 fractions of the methacrylate animals was demonstrated as was a significant increase in the beta fraction of the 3 day group. There was a sustained depression of the alpha 1 fraction in the methacrylate animals in a 3 day and a 5 day time period. It is not felt, however, that this is indicative of a mechanism for the diverse phenomena that have been described secondary to implantation of methyl methacrylate.

Alpha-Globulins↗
PubMedDate not supplied

The Herbert total knee replacement: a longer than three year follow-up.

Thirty personally performed Herbert total knee replacements, evaluated during a 3-year follow-up, were found not to function well. At the end of one postoperative year 6 knees had symptomatic metal synovitis and required replacement. By the end of 3 years the Herbert total knee replacement had functioned in only 12 patients. The largest single follow-up complication was foreign body synovitis, inflammation of the synovium secondary to small free metal fragments produced by the 2 components rubbing against each other during gait.

Arthritis↗