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Biomedical subjects

L F Peterson

Publications and source records attributed to L F Peterson.

At least 19 recordsLinked to original sources
PubMed2000

Estrogen increases hyperemic microvascular blood flow velocity in postmenopausal women.

BACKGROUND: Epidemiologic studies suggest that estrogen replacement therapy (ERT) is protective against vascular disease. ERT confers this benefit by lowering lipid levels and improving arterial function. However, its effect on the microvasculature in vivo is unknown. Thus the purposes of this study were to evaluate effect of estrogen status on the hyperemic response of the microvasculature in vivo in postmenopausal women and to compare the hyperemic response of the microvasculature in postmenopausal women taking ERT with that of premenopausal women. METHODS: We measured forearm microvasculature flow velocity by using a laser Doppler in a cross section of 64 healthy premenopausal and postmenopausal women 23 to 72 years old. Microvasculature blood flow velocity was measured at baseline. throughout 2 minutes of ischemia, and immediately after the ischemic period was terminated (i.e., during the peak hyperemic response). RESULTS: The peak of the hyperemic flow velocity (PHFV) in the postmenopausal women who were taking long-term ERT at usual doses was greater than that of postmenopausal women who were not currently taking ERT (p < .0001). Moreover, the PHFV of postmenopausal women taking ERT was similar to that of premenopausal women. Multivariate regression analysis showed estrogen status and baseline flow velocity to be independent predictors of PHFV. CONCLUSIONS: Current, long-term ERT at usual replacement doses is associated with improved microvascular responses in postmenopausal women, which may explain some of its beneficial vascular effects.

Adult↗
PubMed1997

Exclusion of the nuclear factor-kappa B3 (REL A) gene as candidate for the multiple endocrine neoplasia type 1 (MEN 1) gene.

Multiple endocrine neoplasia type 1 (MEN 1) is inherited as an autosomal dominant disorder, characterized by neoplasia and hyperplasia in specific endocrine organs. The MEN 1 gene, which is most probably a tumor suppressor gene, has been localized to a region of approximately 900 kb on chromosome 11q13. The nuclear factor-kappa B (NF-kappa B) is a transcription factor with pleiotropic expression, which is involved in the regulation of expression of many cellular genes. The p50/p65 heterodimer is the most abundant form of NF-kappa B. The gene encoding the p65 subunit (NF-kappa B3/REL A) was recently localized in the 900-kb MEN 1 region and was considered a good candidate gene for MEN 1. The structure and nucleotide sequence of the NF-kappa B3 coding region in MEN 1 patients were compared with those of non-MEN 1 subjects, to determine the potential role of this gene in MEN 1 tumorigenesis. Southern blot analysis with constitutional DNA from probands of 14 independent MEN 1 families and DNA from four MEN 1 tumor specimens did not reveal any structural abnormality of the NF-kappa B3 gene. Direct sequencing of cDNAs from two affected subjects from 2 different MEN 1 families, as well as nucleotide sequence analysis of exon/intron boundaries in these patients, did not reveal MEN 1-specific point mutations or other small structural aberrations in the NF-kappa B3 gene. These results make it very unlikely that the NF-kappa B3 gene is the gene responsible for the development of MEN 1.

Base Sequence↗
PubMed1986

Revision total knee arthroplasty.

Careful attention to axial alignment, soft tissue balance, and stability will minimize prosthetic failure. In revision arthroplasty a prosthesis designed to replace bone loss with the least constraint possible should be used. In the current series revision of the noninfected failed total knee arthroplasty has provided satisfactory results in 50% to 60% of the patients. We believe that use of the newer implants and instrumentation will improve results markedly.

Adult↗
PubMed1984

The snapping iliopsoas tendon.

Herein we describe a previously seldom recognized variety of snapping hip, which is caused by snapping of the iliopsoas tendon over the iliopectineal eminence when the femur is moved from the flexed position at the hip and extended through 45 degrees of flexion. The finding is demonstrated with the patient supine and gently resisting gravity with the iliopsoas muscle, thus placing it under tension. At approximately 45 degrees of flexion, the iliopsoas tendon in two patients was confirmed radiographically to snap abruptly, coincident with an audible sound over the iliopectineal eminence of the pelvis. We believe that this occurs relatively frequently and is generally asymptomatic.

Adult↗
PubMed1984

Polycentric total knee arthroplasty. A ten-year follow-up study.

After review of the first 209 polycentric total knee arthroplasties (in 159 patients) performed at the Mayo Clinic between July 1970 and November 1971, we found that the calculated probability of the arthroplasty remaining successful ten years postoperatively was 66 per cent. Actual results showed 42 per cent of the arthroplasties to be successful in patients who were still alive at review; another 24 per cent were successful but were in patients who had died or were lost to follow-up before ten years postoperatively. In 34 per cent failure occurred, which we defined as reoperation for any reason, unacceptable pain, or loss of function. The most common causes of failure were instability or ligament laxity (13 per cent), loosening of a component (7 per cent), infection (3 per cent), and patellofemoral joint pain (4 per cent). Prior knee surgery significantly decreased the probability of success, as did axial malalignment of the prosthetic components at operation.

Adult↗
PubMed1981

Unicompartmental knee arthroplasty using polycentric and geometric hemicomponents.

Unicompartmental knee arthroplasty was performed in 207 knees of 179 patients using either a polycentric (188) or a geometric (nineteen) hemicomponent. After an average follow-up of 2.6 years, the results in 184 (89 per cent) of the knees were satisfactory. Pain and the need for ambulatory aids were reduced, and the distance the patients could walk was increased. Twenty-three (11 per cent) of the 207 procedures were rated as failures. The major cause of failure was loosening of the components (tibial in twelve and femoral in one); there also were unexplained pain in five knees, problems with the opposite unreplaced compartment in three, technical error in one, and pain in the patellofemoral joint in one. Nine of 155 intraoperative specimens for bacterial culture obtained during unicompartmental arthroplasty were positive, and two specimens that were positive on culture were obtained during revision of twenty failed unicompartmental arthroplasties. No gross or histological evidence of infection was demonstrated at operation. Based on this study, we concluded that this procedure can provide satisfactory relief of pain, adequate knee motion, and increased levels of independence and activity for patients with unicompartmental disease who are not suitable candidates for proximal tibial osteotomy or total knee replacement.

Adult↗
PubMed1979

Arthrodesis of the knee following failed total knee arthroplasty.

In forty-five patients, who had an arthrodesis because of failed total knee arthroplasty, the cause was infection in forty, instability in two, failure of the prosthesis in two, and loosening in one. The arthrodesis succeeded in twenty-nine (81%) of thirty-six patients who had had a minimally or partially constrained arthroplasty and in five (56%) of nine who had had a hinge-type prosthesis inserted. The reasons for failure were severe bone loss, persistent sepsis, and loss of bone apposition after manipulation. The technique of arthrodesis did not seem to influence the final result. External fixation most commonly had to be used because of the infections and the device was kept in place for an average of ten weeks, after which immobilization in a cast was used until the arthrodesis healed.

Adult↗
PubMed1979

Total joint arthroplasty. The knee.

Total knee replacement has become an established form of treatment for gonarthrosis and usually results in excellent relief of pain and approximately 90 degrees of joint motion with satisfactory joint stability. The anatomic stability that cannot be restored at surgery must be provided for by additional prosthetic stability. Fixation of prosthetic devices, particularly in the tibia, is marginal and results in an increased incidence of loosening when the quality of bone is weak, as in osteoporosis, or when shear stress is increased because of malalignment or prosthetic constraint. Resurfacing techniques provide the greatest options if surgical revision is necessary. Surgical goals should be realistically assessed so as to maintain the best potential for future treatment options.

Arthroplasty↗
PubMed1977

Total hip arthroplasty: an editiorial comment.

Total hip arthroplasty has become an accepted method of management of severe painful problems of the hip. It has undergone some dramatic changes, the major thrust now being to more nearly match the mechanical characteristics of the implant to the bone and cartilage they replace.

Arthroplasty↗
PubMed1977

Current status of total knee arthroplasty.

Total knee arthroplasty has become an acceptable method of surgical management for severe, disabling gonarthropathy. The three major biomechanical classifications of total knee prostheses are minimally constrained, partially constrained, and fully constrained. The major indication for total knew arthroplasty is pain, followed in a much lower frequency by instability, loss of motion, and deformity. The principal contraindications for the various types relate solely to the residual or restorable ligamentous stability of the knee and the degree of bone loss. In general, the greater the instability and bone loss, the more constrained the prosthesis must be Theoretically, loosening rates increase with increasing shear stresses, which are generally highest with the most constrained prostheses. The major complications are sepsis, loosening, and instability. Various prostheses have incorporated patellofemoral resurfacing as the final dimension in producing a total knee arthroplasty. Knee arthroplasty is very effective in preserving functional knee motion, with relief of pain as an alternative to arthrodesis.

Arthroplasty↗
PubMed1976

Uterine anomalies associated with unilateral renal agenesis.

Six cases of concomitant uterine anomalies and absent kidney are reported. Five of these were obstructive in type, 2 representing a mother and daughter relationship. The importance of investigation of the genitourinary system in the presence of uterine anomaly is emphasized. Fertility is unimpaired but obstetric complications are common, especially premature delivery and breech presentation. Treatment can be simple--drainage of unilateral hematocolpos--but excision of the septum may be necessary. The abnormal embryonic development is reviewed.

Adolescent↗
PubMed1976

Polycentric total knee arthroplasty. A two-year follow-up study.

Polycentric total knee arthroplasty provided significant relief of pain in 86 per cent of 500 knees. The independence and activity levels of the patients increased dramatically. The frequency of major complications as reflected by reoperation was 10 per cent in this series. There was a 2.8 per cent deep infection rate. One-third of the infected knees were salvaged and two-thirds required arthrodesis. Loosening of a component was noted in 2.4 per cent. After operation the average range of motion was from 6 to 101 degrees of flexion, for a range of 95 degrees; this was a 5-degree increase over average preoperative motion. Ninety-six per cent of the patients expressed satisfaction with the surgical result.

Adult↗