Neural dynamics of semantic categorization in semantic variant of primary progressive aphasia.

Semantic representations are processed along a posterior-to-anterior gradient reflecting a shift from perceptual (e.g., it has eight legs) to conceptual (e.g., venomous spiders are rare) information. One critical region is the anterior temporal lobe (ATL): patients with semantic variant primary progressive aphasia (svPPA), a clinical syndrome associated with ATL neurodegeneration, manifest a deep loss of semantic knowledge. We test the hypothesis that svPPA patients perform semantic tasks by over-recruiting areas implicated in perceptual processing. We compared MEG recordings of svPPA patients and healthy controls during a categorization task. While behavioral performance did not differ, svPPA patients showed indications of greater activation over bilateral occipital cortices and superior temporal gyrus, and inconsistent engagement of frontal regions. These findings suggest a pervasive reorganization of brain networks in response to ATL neurodegeneration: the loss of this critical hub leads to a dysregulated (semantic) control system, and defective semantic representations are seemingly compensated via enhanced perceptual processing.

Intrahepatic hemorrhage after use of low-molecular-weight heparin for total hip arthroplasty.

Low-molecular-weight heparin (LMWH) has become a popular agent for prophylaxis against deep vein thrombosis and thromboembolic disease after total joint arthroplasty. LMWH allows for consistent dosing in postoperative patients without the need for laboratory monitoring. Hemorrhage is an uncommon but documented adverse reaction when using LMWH; however, intrahepatic hemorrhage has not been previously reported in conjunction with LMWH therapy. We report the case of a woman who suffered intrahepatic hemorrhage presenting with acute abdominal pain and vomiting after the use of enoxaparin for total hip arthroplasty.

Sensorimotor adaptation in speech production.

Human subjects are known to adapt their motor behavior to a shift of the visual field brought about by wearing prism glasses over their eyes. The analog of this phenomenon was studied in the speech domain. By use of a device that can feed back transformed speech signals in real time, subjects were exposed to phonetically sensible, online perturbations of their own speech patterns. It was found that speakers learn to adjust their production of a vowel to compensate for feedback alterations that change the vowel's perceived phonetic identity; moreover, the effect generalizes across phonetic contexts and to different vowels.

Bone mineral density and broadband ultrasound attenuation with estrogen treatment of postmenopausal women.

The purpose of the current study was to determine the changes in lumbar spine, hip, and calcaneus bone mineral density (BMD), and in calcaneus broadband ultrasound attenuation (BUA) in early menopausal women and to assess the effects of estrogen replacement therapy (ERT) on bone mass at these sites over a 2-yr period. Fifty-three Caucasian women who were at least 6 mo postmenopausal were divided into two groups based on estrogen use. Twenty-one women, average age 53.0 +/- 0.6 yr and 2.9 +/- 0.3 yr since menopause, had been receiving estrogen in combination with progesterone for at least 6 mo prior to enrollment in the study. Thirty-two women, average age 52.7 +/- 0.8 yr and 2.8 +/- 0.3 yr since menopause, had never received ERT. During the 2-yr study, women not receiving ERT had significant decreases in BMD of the spine -2.3 +/- 0.6%, femoral neck -2.2 +/- 0.8%, and calcaneus -4.7 +/- 0.9%, and in BUA of the calcaneus -14.3 +/- 1.8%. ERT prevented the decreases in BMD at the spine +0.4 +/- 0.6% and calcaneus -2.3 +/- 1.1%, but did not prevent a significant decrease in bone mass at the femoral neck -1.9 +/- 0.8% and BUA at the calcaneus -17.8 +/- 3.2%. Neither group had significant decreases in total hip BMD. This study demonstrates again that ERT prevents the menopause-associated decreases in spine BMD. However, in this group of women, ERT did not prevent loss in femoral neck BMD or BUA. The results suggest that women being treated with estrogen for maintenance of BMD in early menopause need to be monitored to ensure efficacy of therapy, especially in the maintenance of femoral neck BMD.

Correlations among bone mineral density, broadband ultrasound attenuation, mechanical indentation testing, and bone orientation in bovine femoral neck samples.

Broadband ultrasound attenuation (BUA) of the calcaneus has been found to correlate with bone mineral density (BMD) of the femoral neck. The purpose of this study was to determine if a correlation exists among femoral neck BUA, femoral neck BMD, and incremental indent depth, a qualitative indicator of local mechanical bone strength, in bovine samples, and if this correlation is dependent upon orientation. For 12 of the bovine samples obtained, BUA was measured at the femoral neck and was followed by a BMD determination of the same area. A 19 mm diameter bicortical core containing the center of the area of interest was removed, transversely cut into 7 mm, thick disks, and tested for hardness by indent depth. For these tests, BMD was well correlated with BUA (R2 = 0.85, P < 0.001). An inversely proportional relationship with a modest correlation was found between indent depth and BMD (R2 = 0.59, P = 0.026), and indent depth and BUA (R2 = 0.57, P = 0.031). In a second set of tests involving 15 different bovine samples, a bicortical core was removed from the femoral neck. A trabecular bone cube measuring 1.5 cm on a side was removed from the center of the core. BUA and BMD measurements were made along the anterior-posterior (AP), medial-lateral (ML), and cephalic-caudal (CC) aspects of the cube. The cubes were randomly separated into three groups, cut in half perpendicular to the axis of interest, and tested for hardness by indent depth. In these tests, no significant difference was found in BMD among the three orientations of the cubes scanned (P = 0.77). In contrast, the BUA along the ML orientation of the cube was significantly greater than that along the AP orientation (P < 0.05). No significant difference was found in the incremental indent depth measurements among cube orientations (P = 0.41). In the test involving only trabecular bone, a much higher correlation between BMD and incremental indent depth was found regardless of cube orientation (R2 = 0.64, P < 0.001). The data indicate that BUA, but not BMD, is affected by trabecular orientation, and that BMD is negatively correlated with incremental indent depth.

Humeral bone density losses after shoulder surgery and immobilization.

This study evaluates disuse osteoporosis of the proximal humerus after shoulder surgery and immobilization. This was accomplished by quantifying bone mineral density changes in 22 patients' proximal humeri after 6 weeks of immobilization for soft-tissue shoulder surgery. The bone mineral density of the humeral head, neck, and proximal diaphyseal subregions was determined 1 to 2 weeks before surgery and at 3, 6, and 12 weeks after surgery with dual-energy x-ray absorptiometry. By the sixth postoperative week statistically significant bone mineral density decreases of 6% to 14% were observed in the humeral neck and head subregions, respectively. The changes in these three regions diminished slightly after 6 weeks of remobilization, but the differences were still statistically significant. No significant bone mineral density changes occurred in any subregion or during any time interval in the nonoperated humerus. Our study represents the first report with dual-energy x-ray absorptiometry to quantify bone loss of the proximal humerus of patients after shoulder immobilization. Further long-term study is warranted to determine the clinical significance of this bone loss and to determine whether these losses are partially or fully recoverable.

[Impacted bicuspids--surgical and orthodontic treatment: the Laval experience]. / Les canines incluses--traitement chirurgico-orthodontique: l'expérience de Laval.

It happens that maxillary cuspids do not follow their normal path of eruption and remain impacted. We have reviewed the files of patients presenting with this anomaly and determined which surgical and orthodontic treatments they have received, with the help of a removable appliance.

Correlation of bone mineral density and femoral neck hardness in bovine and human samples.

Bone mineral density (BMD) is a predictor of fracture risk. The purpose of this study was to determine whether a correlation exists between femoral neck BMD and an indicator of mechanical bone strength in human and bovine samples. Human proximal femurs were obtained from seven men and two women undergoing total hip arthroplasty (THA), mean age 60.3 years. Preoperative BMD measurements of the femoral neck were obtained (Lunar DPX). A 3 cm2 area of interest on each excised femoral neck corresponding to the preoperative BMD measurement site was carefully marked and BMD was remeasured postoperatively. Ten excised bovine femoral necks were also measured for BMD. A bicortical core, each cortex 2.8 cm2 in area, containing the center of the area of interest was removed from the human and bovine femoral necks, cut into multiple 7-mm thick, multiple cross-sectional discs, and measured for hardness by indent depth (Rockwell International Hardness Tester, Wilson Mechanical Instruments, New York, NY). In vivo human femoral neck BMD measurements correlated with in vitro BMD measurements (r = 0.99). BMD measurements of human femoral necks were significantly lower than BMD measurements of bovine femoral necks (P < 0.05). Inverse relationships were found between in vivo and in vitro human BMD measurements and indent depth (r = -0.58 and -0.59, respectively). Bovine BMD measurements and indent depth were also inversely related (r = -0.64).(ABSTRACT TRUNCATED AT 250 WORDS)

Bone mineral density changes in the forearm after immobilization.

This study determined the early natural history of disuse osteoporosis in the ulna and radius. Six women and 2 men (mean age, 48.5 years; range, 35-60 years) having surgery on their wrists or hands had bone mineral density determined by single energy xray absorptiometry at 4 sites of the distal radius and ulna before operation, at cast removal (mean, 4.9 weeks after surgery), and after an average of 4.7 weeks of remobilization and hand therapy. A control group of 4 men and 4 women (mean age, 35.6 years; range, 24-46 years) had bone mineral density measurements of both forearms taken initially and again 5 weeks later. The patients had significant loss in bone mineral density at the ulna and distal sites of the forearm after 4.9 weeks of immobilization. Loss of bone mineral density continued at all 4 sites even after 4.7 weeks of remobilization and hand therapy. Bone mineral density increased significantly at the ultradistal radius of the contralateral forearm (which was not operated on) after 4.9 weeks, but this gain was no longer significant after 4.7 weeks of remobilization of the surgically treated forearm, suggesting that increased activity of the nonimmobilized forearm increased bone mineral density at certain sites. No changes in bone mineral density were seen in the control group. Immobilization of the forearm after hand or wrist surgery significantly decreases bone mass in the distal radius and ulna.

Expression and DNA rearrangement of proto-oncogenes in Cas-Br-E-induced non-T-, non-B-cell leukemias.

The Cas-Br-E murine leukemia virus is a non-defective retrovirus that induces non-T-, non-B-cell leukemias in susceptible NIH/Swiss mice. A collection of tumors was examined for genomic DNA structure and RNA expression of known or putative proto-oncogenes and one tumor-suppressor gene, with the aim of identifying genes involved in Cas-Br-E-induced non-T-, non-B-cell leukemogenesis. Fli-1, p53, and Evi-1 were found to be rearranged in 72%, 23%, and 18% of the tumors, respectively, whereas no DNA alteration were detected for c-myc, c-myb, Pim-1, Evi-2, and EpoR genes. Evi-1 rearrangements are rarely associated with p53 or Fli-1 alterations. However, rearrangements of these last two genes are very often associated within the same tumor. Moreover, patterns of coordinated expression of critical cell growth-regulating genes are consistently associated with specific tumor types. These data suggest that Cas-Br-E can induce two types of hematopoietic neoplasias by different mechanisms.

Analysis of proviruses integrated in Fli-1 and Evi-1 regions in Cas-Br-E MuLV-induced non-T-, non-B-cell leukemias.

The DNAs of the Cas-Br-E MuLV-induced leukemias always contain somatically acquired mink cell focus-forming (MCF) recombinant proviruses. MCF recombinants could be involved during leukemogenesis at both preleukemic times and in late-stage tumors. Among the Cas-Br-E-induced non-T-, non-B-cell leukemias, viral integrations were found in the Fli-1 and Evi-1 region in 71% (36 out of 51) and 22% (16 out of 72) of the tumors analyzed, respectively. As an approach to evaluate the contribution of Cas-Br-E MCF recombinant formation in cis-activation of proto-oncogenes, we analyzed the structure of the Fli-1- and Evi-1-associated proviruses by Southern blot hybridization. In Fli-1, we found that the proviruses, ecotropic as well as MCF, are all integrated within a very short DNA region immediately upstream of the initiator ATG, toward the 3' end of a 5' exon (Ben-David, Giddens, Letwin, and Bernstein, 1991, Genes Dev. 5, 908-918). All proviruses are oriented the same way, in the 5' to 3' transcriptional sense. Both provirus types are able to direct the Fli-1 expression to the same extent presumably via a promoter insertion mechanism. Most of the proviruses had no detectable deletion and contained both 5' and 3' LTR sequences with similar U3 sequences. MCF recombinants did not show any selective advantage over ecotropic proviruses for the Fli-1 locus since the frequency of ecotropic to MCF-recombinant virus at the Fli-1 locus was identical to that observed at any other locus. This suggests that the formation of these MCF recombinants is not essential for activation of Fli-1 and that ecotropic Cas-Br-E already possesses the required sequences for full cis-activation of Fli-1. On the other hand, in Evi-1, there is a strict selection for ecotropic proviruses. Presumably, viral genetic elements outside of the U3 region could be critical for the Evi-1 cis-activation.

[Contents of the transversal foramen of the seventh cervical vertebra]. / Le contenu du trou transversaire de la septième vertèbre cervicale.

The purpose of our study was to evaluate the individual variations of the foramen sometimes has the same dimensions as the foramen of the other cervical vertebrae, but it can also be smaller, or absent. In cases where the foramen is present in the seventh cervical vertebra, vascular or nerve structures (or both) can be occasionally observed within. When the transverse foramina are found to contain none of the above structures, what then is to be found within this space? According to our results, the transverse foramina of the seventh cervical vertebra almost universally contain vascular and nerve branches as well as fibrous and adipose tissue. This report concerns the results of the macroscopic and microscopic studies concerning the contents of the transverse foramina of the seventh cervical vertebra.

[The inter-metacarpo-phalangeal spaces]. / Etude des espaces inter-métacarpo-phalangiens.

The study of the inter-metacarpophalangeal spaces on 20 human bodies raises the question of the existence of bursae at this level, in line with recent studies (BOSSEY, MIDY) suggesting that such bursae are present at the level of the foot. Careful dissection and histological studies revealed characteristics compatible with both of the following hypotheses: either there are bursae not described until now in anatomy textbooks, or these are virtual spaces limited by a cul-de-sac of the aponeuroses of the hand in the 2nd, 3rd and 4th spaces. Tissue analysis that could determine more specifically the nature of the limiting membrane of these spaces, as well as pathological studies demonstrating the occurrence of common anomalies of bursae in these spaces, are required in order to conclude definitively on the nature of the inter-metecarpophalangeal spaces.

A comparative study of the spaces between the metacarpal and metatarsal heads.

The study of the spaces between the metacarpal heads on 23 cadavers, raises the question of the existence of bursae at this level. This is in line with recent studies suggesting that such bursae are present at this level in the foot. Careful dissection and histological studies revealed characteristics compatible with both of the following hypotheses: either the existence of bursae not described until now in anatomy text-books, or spaces limited by a cul-de-sac of the aponeuroses of the hand in the 2nd, 3rd and 4th digits. Tissue analyses that could determine more specifically the nature of the limiting membrane of these spaces, as well as pathological studies demonstrating the occurrence of common anomalies of bursae in these spaces, are required in order to conclude definitively the nature of the spaces between the metacarpal heads. The gross anatomical and histological characteristics of the spaces between the metacarpal and metatarsal heads and of their limiting membranes were compared and found to be analogous in our series.

The complete pattern of ocular dominance stripes in the striate cortex and visual field of the macaque monkey.

Ocular dominance stripes in the striate cortex of a macaque monkey were labeled by autoradiography after injection of [3H]proline into one eye. The stripes were reconstructed on a representation of the flattened cortical surface by two independent techniques: one used computer graphics, and the other was the manual unfolding procedure of Van Essen and Maunsell (VanEssen, D. C., and J. H. R. Maunsell (1980) J. Comp. Neurol. 191: 255-281). The two reconstructions differed in many details of the pattern but were in agreement on its general features. As described in earlier studies, the stripes formed a system of parallel bands, with numerous branches and islands. They were roughly orthogonal to the V1/V2 border throughout the binocular segment of the cortex. In the lateral part of the operculum, where the fovea is represented, the stripes were less orderly than elsewhere. In the calcarine fissure the stripes ran directly across the striate cortex from its dorsal to its ventral margin. In the far periphery the stripes for the ipsilateral eye became progressively narrower, eventually fragmenting into small islands at the edge of the monocular segment. The overall periodicity (width of a left- plus right-eye pair of stripes) averaged 0.88 mm but decreased by a factor of about 2 from center to periphery. This decrease was not accounted for solely by shrinkage of the ipsilateral eye stripes. The flattened cortical reconstruction was transformed back into visual field coordinates, using information about visual field topography obtained from the detailed mapping study of Van Essen et al. (Van Essen, D.C., W.T. Newsome, and J.H.R. Maunsell (1984) Vision Res. 24: 429-448), as well as from more limited mapping done in the same monkey that was used for the reconstruction. In the transformed map, the stripes increased in width about 40-fold from the fovea to the far periphery. As deduced previously (LeVay, S., D. H. Hubel, and T. N. Wiesel (1975) J. Comp. Neurol. 159: 559-576; Hubel, D. H., and D. C., Freeman (1977) Brain Res. 122: 336-343), there were portions of the map in which the stripes followed curves approximating isoeccentricity lines, but this relationship was not very exact or consistent. The pattern of stripes appears to be more meaningfully related to the geometry of the cortical surface. This has significant implications for understanding the developmental mechanisms involved in stripe formation.

Neonatal deaths in Alabama. III. Out-of-hospital births, 1940-1980.

Out-of-hospital births in Alabama are characterized with special emphasis on the period from 1970 to 1980. Women having an out-of-hospital birth were more likely to be nonwhite, aged greater than or equal to 35, and multiparous and to have little or no prenatal care. However, within the group of women having out-of-hospital delivery, characteristics which predicted neonatal death included being white, aged less than 20, primiparous, and unmarried and having little or no prenatal care. Both the risk factors for and outcomes of out-of-hospital birth differed markedly by race. In all, out-of-hospital births, which declined from 25% to 0.5% of all births from 1940 to 1980, were associated with a twofold increase in neonatal mortality. The major care provider for out-of-hospital births, the "granny" midwife, was found to have little knowledge about, or ability to provide, modern obstetric care. High-risk status of the patients, limited capability of the care-givers, and lack of appropriate medical resources are suggested as the likely reasons for the excess neonatal mortality in out-of-hospital births.