New stand magnifiers do not meet rated levels of performance

A new range of stand magnifiers has been released by the COIL company in the United Kingdom. Examination of these magnifiers reveals that they fail to deliver the rated magnifications labelled prominently on the appliances, as a result of the manufacturer's conformance with the requirements of the German DIN standard and the use of back vertex power (F'_v) rather than equivalent dioptric power (F_m) of the magnifier. In this study we provide information on the optometric parameters of these new stand magnifiers that will assist the more accurate specification of improvements in vision expected from their use.     

Biomechanical foot therapy

The podiatrist specializing in biomechanical therapy must begin with a solid foundation of standardized definitions in order to discuss theories of mechanical foot treatment as they have been presented and developed over the past century. Equally important, is the building of a working knowledge and familiarity with the wide variety of available materials and their diverse properties. In addition, in order to arrive at an accurate biomechanical diagnosis, the clinician must evaluate the patient from static, dynamic, and radiographic perspectives. One must also keep current in regard to various technological advances in casting and fabrication of orthotic devices, as well as in new developments in biomechanical theory and associated therapy. It also must be kept in mind that functional foot orthoses are not 100 per cent efficient, therefore, their shape, fabrication, and composition should all be devised and prescribed with specific goals for total body mechanics.     

Functional and phenotypic analysis of tumor-infiltrating lymphocytes isolated from human primary and metastatic liver tumors and cultured in recombinant interleukin-2

Tumor-infiltrating lymphocytes (TIL) were isolated from 40 of 51 consecutive human liver tumor samples (primary hepatocellular carcinoma, 16 of 18; metastatic, 23 of 29; benign, one of four). Functional and phenotypic characteristics of fresh and recombinant interleukin-2 (rIL-2)-expanded TIL were evaluated. The expansion of TIL from hepatic tumors in the presence of 1000 units/ml of rIL-2 was possible in 60% of cases. In comparison to TIL from metastatic liver tumors, TIL obtained from primary liver tumors expanded faster and better in rIL-2 cultures. Expanded TIL from primary tumors had significantly higher cytotoxicity against K562 targets, but not Raji targets, than those from metastatic tumors. Cytotoxicity against fresh autologous tumor targets was detected in seven of eight cultures tested. TIL from primary tumors retained antitumor reactivity significantly longer in culture. The optimal in vitro cytotoxicity was achieved between days 20 and 60 of culture in the presence of rIL-2. Antitumor activity was associated with the increase in these TIL cultures of a cell population expressing the Leu19 antigen with or without the CD3 antigen. The frequency of the CD3+Leu19+ population showed a bimodal distribution during culture: the first peak of CD3+Leu19+ cells occurred between days 30 and 60 and was associated with the increased antitumor activity; the second peak occurred after day 60 and was not associated with activity. These findings demonstrate that TIL from most human hepatic tumors can be successfully isolated, cultured in rIL-2, and enriched in Leu19+ effectors. In addition, these TIL upon IL-2 activation in vitro are capable of lysing fresh autologous and/or allogeneic tumor targets.     

Laboratory evaluation of alignment and kinematics in a unicompartmental knee arthroplasty inserted with intramedullary instrumentation.

The purposes of this study were to evaluate the reliability of intramedullary (IM) instrumentation for unicompartmental total knee replacement and to assess the stability characteristics of the knee after implantation of a relatively unconstrained articular surface. Five adult, human cadaver lower extremities including hip, knee, and ankle were used to evaluate IM alignment. Five adult, fresh-frozen knee specimens were used to evaluate knee kinematics. Long anterioposterior roentgenograms were used to evaluate valgus angle and position of the center of the knee relative to the mechanical axis of the lower extremity. IM instrumentation returned the knee to normal alignment in all cases. The greatest valgus angle change was 3 degrees, and the position of the center of the knee relative to the mechanical axis was not significantly altered. Knee kinematics after unicompartmental knee replacement followed the predicted pattern of normal stability in extension and had slightly less varus-valgus laxity at 30 degrees (p less than 0.01), 45 degrees (p less than 0.01), and 60 degrees (p less than 0.05), and less anteroposterior displacement at 45 degrees (p less than 0.01) and 60 degrees (p less than 0.05). This study offers encouraging evidence that unicompartmental knee replacement with unconstrained components can restore normal knee kinematics, and that alignment can be restored with a high degree of accuracy with an intramedullary alignment system.     

Tibial tubercle osteotomy for exposure of the difficult total knee arthroplasty

Tibial tubercle osteotomy provides a safe and reliable means of extensile exposure of the knee. A technique was developed using a long osteoperiosteal segment including the tibial tubercle and upper tibial crest leaving lateral muscular attachments intact to this bone fragment. The bone fragment was reattached to its bed with two cobalt-chromium wires passed through the fragment and through the medial tibial cortex. The procedure was used in 71 knees to expose the joint for total knee arthroplasty, and the follow-up period was one to five years. All healed uneventfully, and no significant complications occurred. Mean postoperative flexion was 97 degrees. No extension lag occurred, and mean flexion contracture was 2.5 degrees. Excellent exposure can be achieved by means of a viable bone flap below the knee. Early rehabilitation and weight bearing can be done with low potential for complications.     

Separation of tumor-infiltrating lymphocytes from tumor cells in human solid tumors A comparison between velocity sedimentation and discontinuous density gradients

The separation of viable tumor-infiltrating lymphocytes (TIL) from surgical biopsies of human solid tumors was achieved by velocity sedimentation at unit gravity or by discontinuous density gradients. The two methods were adapted to small volumes and cell numbers not exceeding 1 × 10⁸. The recovery, purity and composition of the TIL-enriched fractions were comparable in the two methods. Density gradients were more rapid, simpler and more practical for preparation under sterile conditions of TIL from clinical material than velocity sedimentation. Lymphocytes in the TIL-enriched fractions obtained by either of the methods were poorly responsive to mitogens. This poor responsiveness is a characteristic of the human TIL and seems to be related to effects exerted by tumor cells.     

Reactivity of anti-human brain serum with human lymphocytes.

Specific anti-human T-cell serum was prepared in rabbits by multiple subcutaneous injections of human brain homogenates in incomplete Freund's adjuvant. The serum was exhaustively absorbed with human RBCs, lyophilized human liver, lyophilized normal human serum, and peripheral blood lymphocytes from patients with chronic lymphocytic leukemia (CLL). Specificity of the antiserum for human T lymphocytes was tested by indirect immunofluorescence. It stained 70 to 80% of lymphocytes in circulation, 95% of thymus, 27 to 35% of spleen, 5 to 10% of tonsil lymphocytes, and over 90% of phytohemagglutinin-stimulated lymphocytes in vitro. Only T-dependent areas of cryostat-sectioned human lymph nodes stained with the antiserum. It did not stain circulating lymphocytes which formed HEAC rosettes, plasma cells in marrows of multiple myeloma patients or macrophages. After removal of HEAC rosettes by centrifugation in Ficoll-Hypaque, 75% of interface cells formed E rosettes and 65 to 75% stained with the antiserum. The antiserum was used in studies of lymphocytes in chronic and acute lymphocytic leukemias, lymphomas, and other lymphoproliferative diseases. Numbers and distribution in the circulation, spleen and nodes of lymphocytes bearing the T marker were significantly altered in patients with these disorders.