Using motion capture technology to measure the effects of magnification loupes on dental operator posture: A pilot study.

BACKGROUND: Motion analysis has great potential for quantitatively evaluating dental operator posture and the impact of interventions such as magnification loupes on posture and subsequent development of musculoskeletal disorders. OBJECTIVE: This study sought to determine the feasibility of motion capture technology for measurement of dental operator posture and examine the impact that different styles of magnification loupes had on dental operator posture. METHODS: Forward and lateral head flexion were measured for two different operators while completing a periodontal probing procedure. Each was measured while wearing magnification loupes (flip up-FL and through the lens-TTL) and basic safety lenses. RESULTS: Operators both exhibited reduced forward flexion range of motion (ROM) when using loupes (TTL or FL) compared to a baseline lens (BL). In contrast to forward flexion, no consistent trends were observed for lateral flexion between subjects. CONCLUSIONS: The researchers can report that it is possible to measure dental operator posture using motion capture technology. More study is needed to determine which type of magnification loupes (FL or TTL) are superior in improving dental operator posture. Some evidence was found supporting that the quality of operator posture may more likely be related to the use of magnification loupes, rather than the specific type of lenses worn.

Red blood cell polyagglutination: clinical aspects.

Polyagglutination is the term applied to red blood cells (RBCs) that are agglutinated by almost all samples of human sera from adults but not by autologous serum or sera of newborns. The polyagglutinable state may be transient or persistent. Transient polyagglutinability results from the exposure of normally cryptic antigens by bacterial enzymatic activity during the course of an infectious process. RBCs are polyagglutinable because most sera from adults contain agglutinins for the exposed antigens. This type of polyagglutination can often be reproduced in vitro with bacterial culture fluids or isolated enzymes. Persistent polyagglutination may be a consequence of somatic mutation leading to a cellular lineage characterized by an enzyme deficiency that results in exposure of a normally cryptic antigen, Tn. Most human sera contain anti-Tn. Tn polyagglutination is regularly accompanied by leukopenia and thrombocytopenia and has been associated with leukemia. Other forms of persistent polyagglutination are due to the inheritance of rare blood groups or are associated with a hematologic dyscrasia.

Successful transplantation of blood group A2 kidneys into non-A recipients.

The ABO subgroup A2 has been reported to be less reactive with the anti-A1 antibody naturally occurring in the serum of group O and B recipients and to occur in approximately 20% of group A individuals. Between March 1986 and February 1987, the Midwest Organ Bank (MOB) in Kansas City, screened all group A renal donors for the A2 subgroup. A total of 190 cadaverdonor kidneys were retrieved during this time, of which 68 were subgroup A1 and 16 were subgroup A2 (incidence of A2 = 19% of As and 8.5% of all donors). Of the subgroup A2 kidneys, 13 were transplanted into 9 group O and 4 group B recipients. One group O recipient received an HLA-identical A2 living-related graft. Recipients were not preselected or modified by splenectomy, plasmapheresis, or other means, and were treated with cyclosporine, steroids--and, in most cases, azathioprine, after transplantation. There was one hyperacute rejection and there were 5 acute cellular rejection episodes, 3 of which were reversed. One additional patient died at 2.5 months with a functioning graft. Including the successful living-related graft, 10 of 14 patients (71%) have functioning grafts, with a follow-up of 5 to 14 months, and a mean creatinine of 1.7 mg/dl. We find that the A2 subgroup represents a small but important minority of A donors, and that transplantation into non-A recipients can generally, but not universally, be safely accomplished. We recommend the screening of A donors for the A2 subgroup in both the cadaver-donor and living-related groups, and suggest that the utilization of A2 donors in non-A patients may contribute to the transplantation of group O and highly sensitized patients--and, in some cases, improve the degree of HLA matching.

Ten-year experience in transplantation of A2 kidneys into B and O recipients.

BACKGROUND: This article summarizes our 10-year multicenter experience with transplantation of 50 blood group A2 and A2B kidneys into B and O patients. METHODS: Since 1986, we have transplanted kidneys from 46 cadaver donors and 4 living donors who were blood group A2 (47 donors) or A2B (3 donors) into 19 B and 31 O patients. In 1991, we began allocating these kidneys preferentially to B and O recipients who were selected based on a history of low (< or =4) anti-A IgG isoagglutinin titers. Immunosuppression was no different from that used in ABO-compatible grafts. RESULTS: The 1-month function rate before thus selecting the patients was 68% (19/28), but is now 94% (17/18). Two-year cadaver-donor graft survival with this selection method is 94%, compared with 88% for 640 concurrent and consecutive ABO-compatible transplants (log-rank, 0.15). All four living-related transplants are still functioning, with a mean follow-up of 71 months. Since we began allocating A2 kidneys preferentially to B and O recipients, the percentage of the B patients who received A2 or A2B kidneys has increased from 29% (8/28) to 55% (10/18). CONCLUSIONS: Transplantation of A2 or A2B kidneys into B and O patients is clinically equivalent to that of ABO-compatible transplantation when recipients are selected by low pretransplant anti-A titer histories. This approach increases access of blood group B recipients to kidneys.

Transplantation rate of the blood group B waiting list is increased by using A2 and A2B kidneys.

BACKGROUND: We have increased the transplantation rate for blood group B cadaveric waiting list candidates by transplanting them with A2 and A2B kidneys. METHODS: Since 1991, five of the seven renal transplant programs in our organ procurement organization service area have preferentially transplanted blood group A2 and A2B cadaveric kidneys to B blood group waiting list candidates with histories of low anti-A isoagglutinin titers. RESULTS: Between 1991 and 1997, these five centers performed transplantations on 71 patients from the B cadaveric waiting list. Of those 71 patients, 29% (21 of 71) underwent transplantation with either A2 (n=18) or A2B (n=3) cadaveric kidneys. In 1997 alone, 48% (11 of 23) of the B patient transplant recipients received A2 or A2B kidneys. CONCLUSIONS: Transplantation of A2 and A2B kidneys into B waiting list patients has successfully increased access of B patients to kidneys. Such an allocation algorithm implemented nationally may similarly increase the transplantation rate of B waiting list candidates.

Identification of a subset of group B donors reactive with monoclonal anti-A reagent.

Two red blood cell (RBC) units labeled group B were returned to the source blood center after they had been retyped as AB by a transfusion service. The discrepancy could be reproduced, but only with the use of the transfusion service's reagent, Ortho Diagnostic's anti-A Bioclone (a licensed, blended, murine monoclonal anti-A reagent). RBCs from 35 of 3,458 random group B donors (1%) reacted with the monoclonal anti-A after immediate centrifugation. Reactivity was associated with high serum levels of B-gene-specified transferase and was caused by the MH04 component, a potent anti-A capable of detecting some examples of Ax RBCs. It is probable that the potency of MH04 permitted detection of low levels of A determinants synthesized by the donors' unusually strong B-gene-specified transferase. Transfer of N-acetylgalactosamine by B-gene-specified transferases, reported in vitro, has not been detected previously in vivo. Use of highly sensitive monoclonal reagents may result in clinically ambiguous blood grouping results.

Characterization of human erythrocyte alloantibodies by IgG subclass and monocyte interaction.

Human blood group antibodies of 11 specificities were examined for ability to mediate interaction with normal blood monocytes, IgG subclass composition, and titer score. Most antibodies were normally non-complement-binding (except anti-JKa) and clinically significant (except anti-Lub). A simple and relatively rapid in-vitro assay for the visualization of sensitized erythrocyte-monocyte interaction is described. Capillary procedures were adapted for IgG subclass composition determinations. Standard serologic tests were used to assess antibody titer score. A relationship appeared to exist between increased antibody titer score and increased interaction of sensitized erythrocytes (RBC) with normal blood monocytes (MNL), insofar as the mean titer score for antibodies that did mediate significant interaction was 52, whereas titer scores for antibodies that did not averaged 25. One or more examples within all antibody specificity, mediated significant RBC-MNL interaction. No relationship was observed between IgG subclass composition and mediation of RBC-MNL interaction except that all antibodies that did mediate interaction contained IgG1 or IgG3. Characteristic patterns of IgG subclass composition were observed for many antibody specificity groups, although too few examples were tested for valid statistical analysis. This study identifies two features of common blood group antibody populations that are instrumental in mediating erythrocyte destruction by monocytes in vitro. Similar information may be of value in predicting the result of erythrocytes transfused to patients with antibodies of unknown clinical significance.

Fatal intravascular immune hemolysis induced by hydrochlorothiazide.

A patient receiving antihypertensive therapy developed acute intravascular hemolysis and died. Hemolysis was due to an immune process associated with antibody to thiazide. Only two other cases have been reported. Thiazide-induced hemolysis appears to be confined to those patients treated concommitantly with methyldopa.

A solid phase antibody screen.

An automated solid phase antibody screen (SPAS) in microplates has been developed. Red blood cell (RBC) adherence was used as the end point instead of agglutination. Consequently, positive and negative reactions were readily distinguished by a microplate spectrophotometer. The SPAS performed as well as conventional antiglobulin methods for detecting IgG antibodies in donor sera and had increased sensitivity as determined by serial dilutions of antibodies.

A simple alternative for Rh phenotyping red cells that have a persistently positive Rh control.

Investigation of a patient's red cell sample with a persistently positive Rh control revealed that if the patient's red cells were treated with ZZAP, then incubated at 37 degrees C with commercial Rhtyping reagents, then washed four times with saline, the positive Rh control could be circumvented and the Rh phenotype readily determined. One hundred red cell samples of known Rh phenotype were treated with ZZAP and coated with autoantibody to resemble the cells of the index case. Accurate results were obtained when these modified cell samples were tested against Rh typing reagents from three manufacturers using a 37 degrees C incubation followed by four saline washes. The procedure, termed Z37W, appears to be a simple alternative that can assist in determination of Rh phenotypes when the Rh control is positive.

Investigation of transfusion reactions through microcomputer education software.

The purpose of this study was to develop educational software to simulate laboratory investigation of transfusion reactions. An interactive, branching-style program was developed using a 256K Personal Computer (International Business Machines, Boca Raton, FL). Over 75 institutions in the United States and Canada are currently using the software in preprofessional and continuing professional education programs.

Microcomputer software simulating problems in Rh immune globulin prophylaxis and hemolytic disease of the newborn.

Our purpose was to develop educational software that would simulate laboratory investigation of problems in Rh immune globulin prophylaxis and hemolytic disease of the newborn. An interactive, branching style program was developed using a 256K Penonal Computer (International Business Machines, Boca Raton, FL). The software has been used in over 125 institutions for preprofessional and continuing professional education.

Differential reactivity of cardiac and skeletal muscle from various species in two generations of cardiac troponin-T immunoassays.

Cardiac troponin T (cTnT) is being increasingly used as a blood marker of acute or ongoing cardiac injury in various laboratory animals although the range of species in which it is applicable and its tissue selectivity has not been demonstrated. To address this concern, cardiac and skeletal muscle biopsy specimens from various species were homogenised and diluted, and their reactivity was then determined in the first- and second-generation immunoassays for cTnT. Cardiac tissue reactivity was found for all species studies, being highest for rats and several-fold lower for chickens and fish, and intermediate for dogs, pigs, goats, cows, sheep, horses, rabbits, and turkeys. Skeletal muscle had 10 per cent of the reactivity of cardiac muscle in the first-generation assay and 1 per cent of the reactivity of cardiac muscle in the second-generation assay. In the absence of moderate to marked skeletal muscle injury, the second-generation cTnT immunoassay has sufficient reactivity and tissue-selectivity to serve as a blood test for the discrimination between cardiac and skeletal muscle injury in a wide range of species.