Search PubMed⌕ Search

Biomedical subjects

R H Walker

Publications and source records attributed to R H Walker.

At least 73 records · Page 4Linked to original sources
PubMed1985

Comprehensive Blood Bank Survey.

Approximately 2,400 laboratories participated in the 1982 Comprehensive Blood Bank Survey of the College of American Pathologists. Fourteen Referee Laboratories were utilized to validate the results of participants and to assure lack of deterioration of the specimens during shipment. Results of the participants in ABO grouping, Rh D typing, special antigen typing, and antibody detection and identification are reported and discussed. Special ungraded studies, which provided additional challenges, and supplementary questions with the responses of participants are also included.

ABO Blood-Group System↗
PubMed1984

Prediction of outcome of total hip arthroplasty based on initial postoperative radiographic analysis. Matched, paired comparisons of failed versus successful femoral components.

All patients treated by total hip arthroplasty (THA) from 1971 to 1980 were analyzed to assess cause and rate of revision. Multiparameter radiographic analysis of failed femoral components ( FFC ) and matched control THAs was performed to determine predictability of failure, based on initial postarthroplasty and subsequent follow-up radiographic examinations. Rate of revision for all causes was 10.4% (35 THAs ) for 335 THAs in 270 patients with a follow-up period averaging 5.0 (range, 2-10) years. Cause of revision was component loosening in 7.2% (24 THAs ) [23 (6.9%) with femoral component loosening, 3 (0.9%) progressing to stem fracture, 3 (0.9%) with associated acetabular loosening, and 1 (0.3%) with isolated acetabular loosening]; infection in 1.5% (5 THAs ); and 1.8% (6 THAs ) comprised other causes. Older, inactive women, light in body weight (not including 42 THAs for rheumatoid arthritis), had fewer clinical failures. Second revision rate after revision for component loosening was 29% after an average follow-up period of 3.1 years. Paired comparison of initial postoperative and time-of-failure radiographs of 15 patients with THAs requiring revision for femoral component loosening versus initial postoperative and equivalent follow-up radiographs of 15 age-, sex-, weight-, activity-, diagnosis-, prosthesis-, and follow-up-matched patients with clinically successful THAs revealed the FFC group to be worse with regard to the following parameters: on initial postoperative radiographs, (a) femoral and acetabular bone-cement radiolucency (p less than 0.006 and p less than 0.02, respectively) and (b) when analyzed together, femoral bone-cement radiolucency, calcar-collar contact, femoral metal-cement radiolucency, femoral cement mantle adequacy, cement adequacy distal to the femoral component stem tip, and femoral component stem position (p less than 0.006); and on failure/equivalent radiographs, (a) femoral metal-cement radiolucency (p less than 0.01) and (b) when analyzed together, femoral metal-cement and bone-cement radiolucency, subsidence, cortical hypertrophy, calcar resorption, and sclerosis (p less than 0.006).

Adolescent↗
PubMed1984

Management of infected total knee arthroplasties.

In a prospective study of 14 consecutive infected total knee arthroplasties ( TKAs ) treated through 1979, the management consisted of: (1) 11 delayed exchange arthroplasties, with 2 failures requiring above-knee amputation; (2) 2 in situ debridements; and (3) 1 arthrodesis. The final outcome of the delayed exchange arthroplasty group regarding joint pain, patient function, and joint performance was (a) inferior to that of primary TKA (before infection), (b) better than that of resection arthroplasty, and (c) worse than that of a control group of non-infected TKAs respectively. Debridement without prosthesis resection was successful only in cases of immediate postoperative infection (2 successes in 4 TKAs ) and uniformly unsuccessful in infections occurring beyond the perioperative period (4 failures in 4 TKAs ). The study indicates that delayed exchange total knee arthroplasty is a reasonable alternative to arthrodesis following resection of an infected TKA and can be performed without undue risk of recurrent infection.

Aged↗
PubMed1983

The Comprehensive Blood Bank Survey of the College of American Pathologists--1981.

Results of the 1981 Comprehensive Blood Bank Survey of the College of American Pathologists are reported and summarized in tabular form. Excellent results were achieved by the participants in ABO grouping, Rh typing, and crossmatching. Difficulties were encountered by some of the participants in detecting a very weak anti-D and a naturally occurring anti-E. Ungraded specimens were included in this survey and report as well as responses to additional questions utilized to determine current blood bank practices.

ABO Blood-Group System↗
PubMed1983

Quinine-induced thrombocytopenia following intravenous use of heroin.

Profound thrombocytopenia developed in a 22-year-old man after intravenous use of heroin. A high-titer, quinine-dependent, platelet-specific antibody was detected in his serum using lysis of normal platelets labeled with chromium 51 and an electroimmunoassay for measurement of platelet-associated IgG. The antibody was specific for quinine and failed to react with platelets in the presence of quinidine hydrochloride or two structural analogues of heroin. Quinine, a common adulterant found in heroin, was detected in the patient's blood and urine. On the basis of these observations, the patient was judged to have quinine-induced immunologic thrombocytopenia. To our knowledge, this report is the first to confirm that quinine used as an adulterant can induce immunologic thrombocytopenia following an injection of heroin.

Adult↗
PubMed1982

Computerized tomography in assessment of acetabular fractures.

Computerized tomography (CT) can be a useful adjunct to conventional radiography in assessment of acetabular fractures and fracture-dislocations of the hip. Owing to the complex bony architecture of the acetabulum, CT affords better definition of fracture patterns in this region than roentgenography, including special views and tomography. The cross-sectional views of CT offer improved definition of the characteristics of a complex acetabular fracture, including integrity of the weight-bearing dome, congruity of joint surfaces, degree of comminution, size and spatial relationship of fragments, and presence of intra-articular fragments. Computerized reconstruction of sagittal and coronal views at desired levels duplicates polytomography and renders standard tomography unnecessary. Radiation exposure required for a CT examination of the pelvis is equal to or less than that required for a polytomography study. CT can be utilized as a valuable diagnostic aid in the assessment of selected acetabular fractures and fracture-dislocations of the hip, providing often otherwise unobtainable information to the choice of treatment for these difficult injuries.

Acetabulum↗
PubMed1982

The 1980 comprehensive blood bank survey of the College of American Pathologists.

Results of the 1980 Comprehensive Blood Bank Survey of the College of American Pathologists are summarized in tabular form. The overall mean of correct responses among participating laboratories showed a high degree of correlation with Referee Laboratory results in ABO and Rh D typing as well as in crossmatching. Some problems existed in the identification and recognition of multiple alloantibodies and in the identification of an alloanti-c in the presence of rouleaux. Ungraded sample results are reported as well as responses to questions regarding the current standards of practice in hospital blood banks.

ABO Blood-Group System↗
PubMed1981

The results of the 1979 Comprehensive blood bank survey of the College of American Pathologists.

The results of the 1979 Comprehensive Blood Bank Survey of the College of American Pathologists are summarized in tabular form and analyzed. Approximately 2400 laboratories participated in this program. Results of ABO grouping, Rh D typing, and compatibility testing were excellent--over 95% of the participating laboratories obtained the correct responses. Some problems were evident in the recognition of an anti-B in a group B individual, and in the identification of an anti-Cw and an anti-Jka. Sixteen percent of participants reported false positive results in typing with anti-N a cell whose phenotype was M. Other ungraded samples were supplied to provide additional unusual challenges and to review the results of the participants. Many of the questionnaires used in 1978 and 1979 contained additional questions which help define blood bank practices during these years. The responses to these questions are also listed.

Antigen-Antibody Reactions↗
PubMed1981

Irreducible fracture-dislocations of the ankle associated with interposition of the tibialis posterior tendon: case report and review of the literature of a specific ankle fracture syndrome.

A severe closed pronation-eversion fracture-dislocation of the ankle that was irreducible by closed means was encountered. Exploration to accomplish open reduction revealed displacement of the tibialis posterior tendon through the diastasis between the distal tibia and fibula. The tibialis posterior tendon was found to pass posteriorly to an anteriorly between the distal tibia and fibula and laterally to medially across the anterior surfaces of the distal tibia and neck of the talus. Reduction was blocked by the tibialis posterior tendon in its abnormal course. After replacement of the tibialis posterior tendon in its anatomic position, reduction was accomplished. Internal fixation was then performed uneventfully. Two previous similar cases of irreducible ankle fractures due to displacement of the tibialis posterior tendon through the diastasis between the distal tibia and fibula have been reported in the literature. This uncommon syndrome is reported as a possible etiology to be considered when failure of reduction of an ankle fracture is encountered.

Adult↗
PubMed1980

The Comprehensive Blood Bank Survey of the College of American Pathologists--1978.

Approximately 2,200 laboratories participated in the 1978 Comprehensive Blood Bank Survey of the College of American Pathologists. Correct responses of the test results on the blood specimens were determined by 13 Referee Laboratories. Participants' results were compared with Reference Laboratory results. Overall performance on ABO and Rh D typing revealed 98.3% concurrence. Errors in ABO grouping and Rh typing were most frequently found to be "clerical" rather than "technical." Antibody studies and crossmatching revealed variable results in the detection, identification, and evaluation of the clinical significance of a weak, naturally occurring antibody (anti-P1) and in the crossmatching of weak immune antibodies (anti-e and anti-D). Over 95% of participants correctly responded on antibody studies and crossmatching results with a serum containing a moderately strong anti-Fya. Ungraded specimens provided during the year yielded "state of the art" information on a variety of problems.

Antibodies↗