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Biomedical subjects

L Peterson

Publications and source records attributed to L Peterson.

At least 109 records · Page 6Linked to original sources
PubMed1991

Ultrasonography in the detection of partial patellar ligament ruptures (jumper's knee).

The diagnostic performance of ultrasonography (US) in the detection of partial ruptures in the proximal part of the patellar ligament (jumper's knee) was studied. A total of 81 athletes with chronic localized pain suggestive of jumper's knee underwent US examination, and 25 of these received surgical treatment. Of 25 proven partial tendon ruptures at surgery, US correctly indicated the diagnosis in all cases. A cone-shaped, poorly echogenic area exceeding 0.5 cm in length in the center of the patellar tendon in combination with its localized thickening proved to be a reliable indicator of jumper's knee. One case was a true-negative. No false-negative or false-positive case was observed. Soft-tissue radiography in 14 cases showed a localized swelling but did not detect intratendinous soft-tissue abnormalities. US is the method of choice for the evaluation of jumper's knee, as it is cheap, non-invasive, repeatable, and accurate.

Adult↗
PubMed1991

Disc degeneration and associated abnormalities of the spine in elite gymnasts. A magnetic resonance imaging study.

The thoracolumbar spine was examined by magnetic resonance imaging (MRI) and the history of back pain was analyzed in 24 male elite gymnasts (age range, 19-29 years) and in 16 male nonathletes (age range, 23-36 years). Disc degeneration, defined as reduced disc signal intensity, was significantly more common in athletes (75%) than in nonathletes (31%). The gymnasts also had a higher incidence of other abnormalities of the thoracolumbar spine, and there was a significant correlation between reduced disc signal intensity and the other abnormalities among the gymnasts. There were also significant correlations between back pain and reduced disc signal intensity and abnormal vertebral configuration when the gymnasts run a high risk of developing severe abnormalities of the thoracolumbar spine, and they often have a history of back pain.

Adult↗
PubMed1991

Four different mutations in codon 28 of alpha spectrin are associated with structurally and functionally abnormal spectrin alpha I/74 in hereditary elliptocytosis.

Hereditary elliptocytosis (HE) Sp alpha I/74 is a disorder associated with defective spectrin (Sp) heterodimer self-association and an abnormal tryptic cleavage of the 80-kD alpha I domain of Sp resulting in increased amounts of a 74-kD peptide. The molecular basis of this disorder is heterogeneous and mutations in codons 28, 46, 48, and 49 (codons 22, 40, 42, and 43 in the previous nomenclature which did not include the six NH2-terminal amino acids) have been reported. In this study we present data on seven unrelated HE Sp alpha I/74 kindred from diverse racial backgrounds in whom we identified four different mutations all occurring in exon 2 of alpha Sp at codon 28. Utilizing the polymerase chain reaction we established a CGT----CTT; Arg----Leu 28 mutation in one kindred of Arab/Druze origin. In two unrelated white kindred of English/European origin the substitution is CGT----AGT; Arg----Ser 28 and in two apparently unrelated white kindred from New Zealand, the mutation is CGT----TGT; Arg----Cys 28. Finally, in one American black kindred and in a black kindred from Ghana the mutation involves CGT----CAT; Arg----His 28. Allele specific oligonucleotide hybridization confirmed that the probands are heterozygous for the respective mutant alleles. All four point mutations abolished an Aha II restriction enzyme site which allowed verification of linkage of the mutation with HE Sp alpha I/74. Our results imply that codon 28 of alpha Sp is a "hot spot" for mutations and also indicate that Arg 28 is critical for the conformational stability and functional self association of Sp heterodimers.

Base Sequence↗
PubMed1990

Identification of adverse events occurring during hospitalization. A cross-sectional study of litigation, quality assurance, and medical records at two teaching hospitals.

STUDY OBJECTIVES: To estimate the efficacy of a medical record review for identifying adverse events and negligent case suffered by hospitalized patients. DESIGN: Cross-sectional study comparing an objective medical record review with information available from hospital quality assurance records as well as risk management and litigation records. SETTING: Two metropolitan teaching hospitals in the northeastern United States. MEASUREMENTS AND MAIN RESULTS: Using the litigation and risk management records as a criterion standard, we found that the medical record review had a sensitivity of 80% (93 of 116; 95% CI, 73% to 88%) for discovering adverse events and a sensitivity of 76% (51 of 67; 95% CI, 66% to 86%) for discovering negligent care. We estimated that record review of a random sample of hospitalizations across a geographic region would have even higher sensitivity (adverse-event sensitivity, 84%; negligence sensitivity, 80%). Moreover, we found that the adverse events we failed to discover led to less costly malpractice claims. A significant number of adverse events (20 of 172) among hospitalizations never gave rise to litigation or risk management investigation. Six of the twenty were due to negligent care. Quality assurance efforts at the level of the clinical departments in one hospital led to review of only 12 out of 82 risk management records. CONCLUSIONS: The overwhelming majority of adverse events and episodes of negligent care are discoverable with the methods we used to evaluate medical records. Quality assurance efforts using similar record review methods should be further evaluated.

Cross-Sectional Studies↗
PubMed1990

Parental injury prevention endeavors: a function of health beliefs?

Investigating parents' beliefs about injury prevention may yield important information for planning preventive interventions. A comprehensive description of parents' beliefs about injury prevention is presented in this study, and effects of child age and sex are described. In addition, a health belief model was successfully used to predict parent-reported teaching of safety skills and preventive environmental interventions. The model successfully cross-validated the prediction in two independent samples. Parents reported low feelings of susceptibility or worry about injury. The variables most associated with parental preventive endeavors were the belief that intervention can avoid injury, a realistically high appraisal of the amount of time involved, and feelings of high knowledge and competence to teach safety skills. Implications of these data for designing more effective behavioral interventions are described.

Accident Prevention↗
PubMed1990

Anthropometric characteristics, passive hip flexion, and spinal mobility in relation to back pain in athletes.

Anthropometric characteristics, passive hip flexion, and spinal mobility were examined and back pain was registered in 116 top Swedish male athletes representing four different sports (wrestling, gymnastics, soccer, tennis). Differences in stature, body weight, passive hip flexion, mobility of the spine in forward flexion, and asymmetry of the back were found when each group of athletes was compared with the rest of the athletes. These differences could be explained by a natural selection of individuals with the physical constitution required for the sport concerned, but they may also be a long-term effect of training. A small sacral inclination, defined as the sacrohorizontal angle, correlated significantly with back pain.

Adolescent↗
PubMed1990

The role of CD4+ helper T cells in the destruction of microencapsulated islet xenografts in nod mice.

Islet transplants for large numbers of patients with diabetes will require xenografts. Microencapsulation is an appealing method for islet xenografting. However, graft function has been limited by a cellular reaction, particularly intense in spontaneously diabetic, NOD mice. The purpose of this study was to elucidate the mechanism of this reaction. Poly-1-lysine-alginate microcapsules containing 4000-12,000 dog or 1800-2000 rat islets were xenografted intraperitoneally into streptozotocin (SZN)-diabetic C57BL/6J and NOD mice, with or without recipient treatment with GK 1.5 (anti-CD4 monoclonal antibody) (20-30 microliters i.p. every 5 days, begun on day -7. Grafts were considered technically successful if random blood glucose (BG) was normalized (less than 150 mg/dl) within 36 hr. Graft failure was defined as BG greater than 250 mg/dl. Dog and rat islets in microcapsules normalized BG in both SZN and NOD mice within 24 hr routinely. Empty microcapsules and GK 1.5 treatments alone did not affect BG. NODs destroyed both microencapsulated dog and rat islets more rapidly than did SZN-diabetic mice (P less than .01). Graft biopsies showed an intense cellular reaction, composed of lymphocytes, macrophages and giant cells, and no viable islets. GK 1.5 treatment significantly prolonged both dog-to-NOD and rat-to-NOD grafts (P less than 0.01). Biopsies of long-term functioning grafts (on days 65-85) demonstrated viable islets and no cellular reaction around microcapsules; 1/4 rat and 1/8 dog islet xenografts continued to function indefinitely in NOD recipients, even after cessation of GK 1.5 therapy. Prediabetic NODs receiving encapsulated dog or rat islets mounted a moderate cellular reaction to grafts. Empty microcapsules excited no cellular reaction in diabetic or prediabetic NODs. We conclude that the NOD reaction to microencapsulated xenogeneic islets is helper T cell-dependent, and that the target of this reaction is not the microcapsule itself, but the donor cells within.

Animals↗
PubMed1990

Anterior cruciate ligament repair with and without augmentation. A prospective 7-year study of 51 patients.

A prospective comparison was made of the 7-year results of repair of the acutely ruptured anterior cruciate ligament with and without augmentation using the longitudinal patellar retinaculum. The knee stability was evaluated by clinical tests and by a specially constructed testing device. In the repair group, 6/22 had unchanged activity and intensity levels compared with 24/29 in the augmentation group. Lysholm's functional score was higher in the augmentation group. All the clinical tests and all the objective measurements except Lachman's test showed better stability in the augmentation group.

Adolescent↗
PubMed1990

Microencapsulated dog and rat islet xenografts into streptozotocin-diabetic and NOD mice.

Microencapsulation is an appealing method for islet xenografting. However, graft failure has been related to a cellular reaction, particularly intense in spontaneously diabetic, NOD mice. The goal of this study was to characterize this reaction. Poly-l-lysine-alginate microcapsules containing dog or rat islets were xenografted intraperitoneally into streptozotocin (SZN)-diabetic C57BL/6J and spontaneously diabetic NOD mice, with or without recipient treatment with GK 1.5 (anti-CD4 monoclonal antibody). Both dog and rat islets in microcapsules normalized blood glucose (BG) routinely in both SZN and NOD mice within 24 hours. Empty microcapsules and GK 1.5 treatment did not affect BG. NODs destroyed both microencapsulated dog and rat islets more rapidly than did SZN-diabetic mice (P less than 0.01). Graft biopsies showed an intense cellular reaction and no viable islets. GK 1.5 treatment significantly prolonged both dog-to-NOD and rat-to-NOD grafts (P less than 0.01). Biopsies of long-term functioning grafts (on days #70-#95) demonstrated viable islets and no cellular reaction. In prediabetic NODs, encapsulated dog and rat islets elicited a moderate cellular reaction. Empty microcapsules excited no cellular reaction in either diabetic or prediabetic NODs.

Animals↗
PubMed1990

Soft-tissue radiography, computed tomography, and ultrasonography of partial Achilles tendon ruptures.

Ultrasonography (US) was compared with soft-tissue radiography (STR) and computed tomography (CT) for demonstration of partial Achilles tendon ruptures. Thirty-nine patients suffering from chronic localized painful Achilles tendon swelling were examined. The patients had all undergone a previous clinical examination, resulting in a suspicion of a non-healed partial tear in 62 out of the 78 tendons. STR showed unspecific tendon pathology such as thickening and diffuse tendon margins. CT resulted in a better delineation of intra- as well as extratendinous abnormalities compared to STR. Various pathologic changes were seen on CT in 54 tendons and in 29 of these, localized intratendinous hypodensities indicated partial ruptures. At US, abnormal changes were observed in 69 tendons, of which 54 had discontinuity of tendon fibers, focal hypoechoic areas, and localized swelling indicating partial ruptures. In 9 cases with surgically proven partial ruptures, US was correct in all cases, while CT was false-negative in 3. STR only showed localized swelling. It was concluded that US was a better method than STR and CT for the detection of partial ruptures and the US findings correlated well with the surgical findings.

Achilles Tendon↗
PubMed1990

Radiologic abnormalities of the thoraco-lumbar spine in athletes.

A radiologic study of the thoraco-lumbar spine was performed in 143 (117 male and 26 female) athletes (wrestlers, gymnasts, soccer players and tennis players), aged 14 to 25 years and 30 male non-athletes, aged 19 to 25 years. Film interpretation was made after mixing the films from all groups and without knowledge of the individual's identity. Various types of radiologic abnormalities occurred in both athletes and non-athletes but were more common among athletes, especially male gymnasts and wrestlers. Abnormalities of the vertebral ring apophysis occurred exclusively in athletes. Combinations of different types of abnormalities were most common in male gymnasts and wrestlers.

Adolescent↗
PubMed1989

Isolation and characterization of three class II MHC genomic clones from the chicken.

A genomic library was constructed from sperm DNA from an individual of the inbred chicken line G-B2, MHC haplotype B6. The library was screened with a chicken class II probe (beta 2 exon specific) and three MHC class II beta chain genomic clones were isolated. The restriction maps of the three clones showed that each of the three clones was unique. The position of the beta chain sequence was located in each of the three genomic clones by Southern blot hybridization. Subclones containing the beta chain gene were produced from each of the genomic clones and the orientation of the leader peptide, beta 1, beta 2, transmembrane, and cytoplasmic exons was determined by Southern blot hybridization and nucleotide sequencing. The complete nucleotide sequence of two of the three subclones was determined. Comparison of the nucleotide and predicted amino acid sequences of the two subclones with other class II beta chain sequences showed that the B6 chicken beta chain genes are evolutionarily related to the class II beta chain genes from chickens of other MHC haplotypes, and to class II beta chain genes from other species. Analysis of Southern blots of B6 chicken DNA, as well as the isolation of the three beta chain genes, suggests that chickens of the B6 haplotype possess at least three MHC class II beta chain genes.

Amino Acid Sequence↗
PubMed1989

The repair of experimentally produced defects in rabbit articular cartilage by autologous chondrocyte transplantation.

Using the knee joints of New Zealand White rabbits, a baseline study was made to determine the intrinsic capability of cartilage for healing defects that do not fracture the subchondral plate. A second experiment examined the effect of autologous chondrocytes grown in vitro on the healing rate of these defects. To determine whether any of the reconstituted cartilage resulted from the chondrocyte graft, a third experiment was conducted involving grafts with chondrocytes that had been labeled prior to grafting with a nuclear tracer. Results were evaluated using both qualitative and quantitative light microscopy. Macroscopic results from grafted specimens displayed a marked decrease in synovitis and other degenerative changes. In defects that had received transplants, a significant amount of cartilage was reconstituted (82%) compared to ungrafted controls (18%). Autoradiography on reconstituted cartilage showed that there were labeled cells incorporated into the repair matrix.

Animals↗
PubMed1989

Diazepam improves recording of lumbar and neck somatosensory evoked potentials.

To determine whether the decrease in muscle artifact provided by diazepam is of sufficient clinical value to justify its use, somatosensory evoked potentials recorded in examinations of 73 consecutive patients were compared with those recorded from 33 subsequent patients who were given 10 mg of diazepam orally just before the examination. With diazepam pretreatment there was clear improvement in the quality of lumbar and neck recordings--increased reproducibility and definition and ease of measurement--and also greater tolerance of the procedure and a slight shortening of time required for the test.

Adult↗
PubMed1989

Parental problem-solving skills, stress, and dietary compliance in phenylketonuria.

Parents of 30 children with phenylketonuria (PKU) who were classified as being in good dietary control (compliant, measured as within the medically acceptable range of blood phenylalanine levels of 2-10 mg) or poor dietary control (noncompliant, measured as either below or above medically acceptable 2-10 mg blood phenylalanine levels) engaged in verbal and written problem-solving situations under conditions of both high and low time-pressure induced stress. Overall, compliant parents gave higher quality verbal and written problem-solving solutions than noncompliant parents. Stress reduced the quality of problem solving in both compliant and noncompliant parents, but even under high stress, compliant parents demonstrated better problem-solving abilities than noncompliant parents. The potential importance of these findings for preventive intervention in PKU families is discussed.

Adolescent↗