Effects of trabecular bone on marrow relaxation in the tibia

Previous studies attributed the characteristic shape changes found in cancer cells, in part, to aberrant vesicle traffic. Typically, transformed cells also rounded up. These phenomena were further investigated by measuring the shape features of cells from established lines, which represented both normal and oncogenic stages of transformation. Although conventional pattern recognition methods, applied to a combined data set from these lines, failed to reveal any new, recognizable features beyond those already known, factors did describe such features. Factors are hypothetical variables that contribute to the variance of two or more measurable variables. One factor for the cell edge, 5, was known from previous studies on correlations among the variables. Several other factors at the same level identified crucial features. Factor 4 reflected the frequency of microspikes; another factor described a knob-like structure (7). A third, factor 16, indexed the variability in projection size. Factors of the upper cell, 1 micrometer or more above the substratum, namely, 1, 2, 8, 11, 13, and 19, also described transformation-related changes. Comparing lines that modeled the development of bronchogenic carcinoma, we found a tendency for 2 (surface smoothing), 4, and 12 (rounding-up) to be changed irreversibly. Thus, factors overcame the problem of relating mathematical shape phenotypes, previously obtained based on single variables, to cell features.     

The relationship in experience between various types of affect.

Investigated the co-occurrence in experience of various emotions placing the focus on positive vs negative affect. In Study 1, 72 college students read stories designed to produce varying levels of either positive or negative affect and then rated their level of both types of affect. In Study 2, 42 undergraduates rated their feelings during emotional times in everyday life for a period of 6 wks. Results show that emotions of the same hedonic valence (e.g., fear and anger) tend to co-occur. Results also show that positive and negative affect do not occur together at high levels of intensity. It is suggested that these 2 facts about the relation of positive and negative affect are probably responsible for the bipolarity that is often found between them. These findings represent a challenge to those who postulate that there are unrelated discrete emotions and that the terms positive affect and negative affect do not describe meaningful clusters of emotions. Findings suggest that if one type of affect is of low intensity, the other type can be at any level from low to high. Therefore, a truly inverse and linear relation does not characterize positive and negative affect. This finding represents a challenge to most structural models of emotion. It appears that mutual exclusion only at high levels of intensity characterizes the relation between positive and negative affect. (2 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Vascularized bone grafts for congenital pseudarthrosis of the tibia

Eight vascularized fibula grafts and two vascularized rib grafts were used for the treatment of 10 Boyd's Type II congenital pseudarthrosis of the tibia. All but one vascularized fibula graft united within 4 months. The two vascularized rib grafts did not unite until receiving a conventional bone graft. Nine spontaneous fractures were seen in four patients; all were subsequently treated successfully with cast or conventional bone graft. Corrective osteotomies were done in two patients. Follow-up averaged 8 years and 5 months (range, 5 years and 1 month to 14 years and 4 months). Average age at end of follow-up was 13 years and 6 months (range, 7 years and 10 months to 20 years and 4 months). After bony union was achieved, shortening of the affected leg averaged 3.8 centimeters, flexion deformity averaged 20 degrees, and valgus deformity averaged 24 degrees. In three patients, whose leg discrepancy averaged 4.9 centimeters, the leg was lengthened at an average patient age of 13 years and 9 months (age range, 11 years and 7 months to 15 years and 2 months). The resulting limb length discrepancy averaged 2.2 centimeters. Vascularized bone grafting is a reliable technique for achieving bony union in congenital pseudarthrosis of the tibia. Residual shortening may be corrected later by limb lengthening.     

Structural changes with aging in cortical bone of the human tibia

Structural modifications are considered to play a significant role in the age-related alterations of bone quality and strength. Senescent compact bone is characterized by an increasing heterogeneity of aspects, including high numbers of lowly mineralized osteons as well as the presence of osteons with hypermineralized lamellae or with a notched haversian canal wall, and of double-zone osteons. These latter three types of osteons are different from the structures involved in the haversian remodeling. In the present study, blocks of midshaft tibia from 7 young men (18-39 years), 14 aged men (50-92 years) and 15 aged women (57-96 years) were embedded in methyl methacrylate in order to perform microradiographic and histomorphometric analysis of undecalcified sections. The intracortical porosity was higher in the aged men than in the young ones, as were the numbers of haversian structures and, to a lesser extent, the diameters of the haversian canals. The aged women showed the same tendency, with cortical porosity still higher than in the men. The osteons with hypermineralized lamellae, those with a notched canal and the double-zone osteons appear to constitute large subgroups of the total haversian population, even in the early adult life. Among them, only the osteons with a notched canal wall increased in frequency with age. The 3 types are much more numerous than the structures involved in the typical haversian remodeling. The correlations between their frequencies as well as their significant topographic association corroborates the hypothesis that the hypermineralized lamellae may crumble down because of their excessive brittleness, giving rise to the haversian canals with notched walls. These enlarged canals could be refilled by bone apposition and result in the double-zone osteons. The 3 types of osteons could constitute different steps of one mechanism of bone desintegration and repair occurring very progressively, which might contribute to modify the bone quality and to increase the intracortical porosity.     

Finite element analysis of the implanted proximal tibia: a relationship between the initial cancellous bone stresses and implant migration

Human rhodopsin kinase (RK) and a carboxyl terminus-truncated mutant RK lacking the last 59 amino acids (RKC) were expressed in human embryonic kidney 293 cells to investigate the role of the carboxyl terminus of RK in recognition and phosphorylation of rhodopsin. RKC, like the wild-type RK, was detected in both plasma membranes and cytosolic fractions. The C-terminal truncated rhodopsin kinase was unable to phosphorylate photo-activated rhodopsin, but possesses kinase activity similar to the wild-type RK in phosphorylation of small peptide substrate. It suggests that the truncation did not disturb the gross structures of RK catalytic domain. Our results also show that RKC failed to translocate to photo-activated rod out segments. Taken together, our study demonstrate the carboxyl terminus of RK is required for phosphorylation of photo-activated rhodopsin and strongly indicate that carboxyl-terminus of RK may be involved in interaction with photo-activated rhodopsin.     

The relationship of increased capillary filtration and bone formation

The effect of functional activity on bone formation and interstitial fluid space in a standardized tibial defect was measured in 19 dogs with one hind limb elevated and the other weight bearing and in 15 dogs bearing weight on all four legs. The interstitial fluid space (V(isf)) of the woven bone of the weight-bearing defect was larger than that in the elevated legs at seven and 14 days. By 28 days, this difference disappeared. In a third group of six dogs, medullary canal pressure was measured in the immobilized and weight-bearing tibias. The pressures were higher in the weight-bearing tibiae at two, three, four, and five days. Because the increase in V(isf) in the weight-bearing defects coincided with the onset of woven bone formation in the defects and an increase in medullary canal pressure, an increase in venous pressure could increase capillary pressure and capillary filtration. Such an increase in filtration might cause the larger V(isf) in the weight-bearing defects and better capillary perfusion of precursor cells of the osteoblast. A hypothesis is that increased fluid flow from increased capillary filtration might produce streaming potentials, a possible signal for increased cellular activity.     

Bone marrow capacity for bone cells and trabecular bone turnover in immobilized tibia after sciatic neurectomy in mice

Pseudomonas aeruginosa and Candida albicans were reported to adhere to the glycosphingolipid asialo-GM1 by means of pili and fimbriae, respectively. These diverse adhesins have been previously reported to have an immunologically conserved antigenic epitope and the role of this cross-reactive epitope in adherence to asialo-GM1 was investigated in this study. Both the unbiotinylated PAK pilus and fimbrial adhesins inhibited biotinylated pili from P. aeruginosa PAK and biotinylated C. albicans fimbriae binding to asialo-GM1 and receptors present on human buccal epithelial cells (BECs), which suggested that the same receptor sites were recognized by the two adhesins. Monoclonal antibodies PK99H and Fm16 raised against the P. aeruginosa PAK pili and C. albicans fimbriae, respectively, recognized a conserved epitope present on the two adhesins. Both Fm16 and PK99H blocked fimbriae binding to asialo-GM1 and BEC receptors and also inhibited P. aeruginosa and C. albicans whole cell binding to BECs. These data suggested that the conserved epitope confers receptor-binding properties to the adhesins, demonstrated that (i) asialo-GM1-like receptors present on epithelial cell surfaces are utilized by the pilus and fimbrial adhesins and (ii) the binding to these glycoreceptors is mediated by a conserved epitope that has receptor-binding properties.     

Reliability of phase-velocity measurements of tibial bone

BACKGROUND AND PURPOSE: The Bone Stiffness Measurement Device-Swing is capable of measuring the propagation velocity of flexural waves in human tibial bone, which relates to bending stiffness. If the interrater and intrarater reliability of measurements obtained with the device are established, it can be used with confidence in assessing changes in bone. The purposes of this study were to detect potential sources of measurement error and to establish the interrater and intrarater reliability of measurements taken with the device. SUBJECTS AND METHODS: In the first part of the study, a random-effects design was used to obtain phase-velocity measurements in subjects without known orthopedic or neurological impairments. The second part of the study consisted of possible applications of the device with mixed designs on subjects with spinal cord injuries. By means of generalizability theory, multiple sources of error (eg, occasion, clinician, repetition) were estimated. For the clinical trial, 17 persons with spinal cord injuries not older than 5 weeks were tested. RESULTS: The standard error of measurement (SEM) for intrarater reliability measurements ranged from 7.3 to 9.8 m x s(-1) . The SEMs for interrater reliability measurements ranged from 5.7 to 9.5 m x s(-1). The SEMs for measurements obtained by a single clinician in a clinical population ranged from 11.9 to 39.7 m x s(-1). CONCLUSION AND DISCUSSION: The reproducibility of measurements obtained with the device is suitably high for the device to be used for evaluation in clinical and research settings.     

Limb salvage with osteoarticular allografts after resection of proximal tibia bone tumors

A retrospective study was performed between 1980 and 1995 on 38 recipients of proximal tibial allografts after wide resection of benign and malignant tumors. Twenty-one (55%) patients experienced one or more complications. Of the 26 patients who received chemotherapy, 15 (58%) experienced one or more complications, whereas of the 12 patients who did not receive chemotherapy, six (50%) experienced one or more complications. In the chemotherapy group, there were 12 (46%) fractures, four (15%) infections, three (12%) nonunions, and four (15%) instabilities. In the nonchemotherapy group there were three (25%) infections, two (17%) fractures, one (8%) instability, and one (8%) nonunion. These complications were managed adequately with multiple subsequent surgical procedures. Three patients underwent amputations for deep wound infections. Twelve (32%) patients underwent removal of the allograft, and the limb was salvaged by reallografting or by total knee arthroplasty. The results of both groups were 66% (25 of 38 patients) satisfactory (good or excellent). The chemotherapy group had a significantly higher incidence of fractures. All other complication rates and functional outcomes were not significantly different between these groups.     

Axial strain measurements in skeletal muscle at various strain rates

A noncontact optical system using high speed image analysis to measure local tissue deformations and axial strains along skeletal muscle is described. The spatial resolution of the system was 20 pixels/cm and the accuracy was +/- 0.125 mm. In order to minimize the error associated with discrete data used to characterize a continuous strain field, the displacement data were fitted with a third order polynomial and the fitted data differentiated to measure surface strains using a Lagrangian finite strain formulation. The distribution of axial strain along the muscle-tendon unit was nonuniform and rate dependent. Despite a variation in local strain distribution with strain rate, the maximum axial strain, Exx = 0.614 +/- 0.045 mm/mm, was rate insensitive and occurred at the failure site for all tests. The frequency response of the video system (1000 Hz) and the measurement of a continuous strain field along the entire length of the structure improve upon previous noncontact optical systems for measurement of surface strains in soft tissues.     

The relationship between static lower extremity measurements and rearfoot motion during walking

Despite the fact that clinicians regularly perform static lower extremity measurements on their patients, to date, little research has been published supporting their ability to predict dynamic rearfoot motion. The abilities of static measurements to predict dynamic foot motion could have important implications considering the fact that excessive rearfoot motion has been associated with various injuries of the lower extremity. The purpose of this study, therefore, was to determine if static lower extremity measurements could be used to predict the magnitude of rearfoot motion during walking. Rearfoot motion of each lower extremity was measured from videotape in 27 healthy young adult subjects with a mean age of 26.1 years. In addition, 17 static measurements were measured and recorded bilaterally for each subject. The results of a multiple regression analysis indicated that the only variable that was able to predict maximum rearfoot pronation was the "difference in navicular height" (r2 = .17). None of the 17 measurements were found to predict time to maximum pronation. These results indicate that static measurements of the lower extremity and foot are poor predictors of dynamic rearfoot motion as measured by maximum pronation or time to maximum pronation in healthy individuals without severe foot deformities.     

Quantitative ultrasound of the tibia: a novel approach for assessment of bone status

We prospectively investigated the appropriateness of Mechanism of Injury as an exclusive indicator for trauma center triage. For all patients transported to our level 1 trauma center, EMS personnel identified applicable American College of Surgeons' Committee on Trauma field triage guidelines. A total of 112 questionnaires were completed. Mechanism of injury was the only reason for trauma center transport in 29. Neither intubation nor emergent surgery was required in any of these patients, and all survived. Only two had an ISS > 15. The remaining 83 patients had an 11% mortality rate. Fourteen (16.9%) had ISS scores > 15. Defining an ISS of 16 or greater as severe injury, mechanism of injury alone had a positive predictive value of only 6.9%. Mechanism of injury may not, by itself, justify bypass of local hospitals in favor of trauma centers.     

Variation of morphometric measurements in bone biopsies (author's transl)

The variation of histomorphometric data in a bone biopsy cylinder of the iliac crest was determined in order to derive a rule of the sampling procedure in such a biopsy specimen. Measurements in different cylinders of a biopsy zone in the right and the left iliac crest were obtained in order to determine the magnitude of change necessary for the recognition of therapeutic or spontaneous alterations performing sequential biopsies.     

Problems of various fixation methods for open tibia fractures: experience in a Japanese level I trauma center

A method is described for making permanent histological sections of prostate carcinoma material obtained by fine needle aspiration (FNA) under ecography guidance. Smears made from prostate aspirates were used for diagnosis and from the same patient remaining aspirates were expelled into fixative filled microcentrifuge tube. Aspirates were pelleted and further processed to paraffin blocks. Permanent histological sections were obtained and each section was defined as satisfactory when it contained about 200 intact tumor cells. We have used these tumor sections and immunocytochemistry (ICC) procedures to study molecular biological marker expression. The technique described here has proven to be easy to use and offered a fast, reliable and cost-effective method to obtain suitable samples for standard ICC and in situ apoptosis detection from FNA prostate carcinoma. The method should be equally suitable for outpatient use on other tumors in which FNA and ICC or in situ apoptosis detection is likely to be helpful.     

Reproducibility of bone height measurements made on serial radiographs

A seventy-three-year-old woman had symptoms of aortic dissection. Initial computed tomographic (CT) scan and angiography showed an extensive intramural hematoma (IMH) of the aortic segment from the ascending aorta to the bulk of the descending aorta without intimal tear or false lumen. Two weeks later the patient's symptoms recurred. A repeat CT demonstrated a classic type A aortic dissection with a false lumen and an intimal defect. The patient underwent a successful hemiarch repair with use of selective cerebral perfusion under profound hypothermic circulatory arrest. This case suggests extensive IMH as an important underlying pathology of the aortic dissection.     

Cestodosis in battery-housed laying hens

Cestodosis in battery-housed laying hens severely reduced egg production particularly at the time of peak production. Hens were able to consume large numbers of Musca domestica, the intermediate host of Choanotaenia infundibulum following the use of an aerosol insecticide to control flies. A considerable discharge of cestodes followed the use of "Lintex" in the feed resulting in a marked improvement in egg production. The use of an insect growth regulator in the feed showed promise in controlling the breeding of flies.