Comparison of acute responses to isotonic or isokinetic eccentric muscle action: differential outcomes in skeletal muscle damage and implications for rehabilitation.

Both isotonic and isokinetic eccentric muscle contractions are commonly used in muscle research laboratories to induce muscle damage, yet, the muscle damage outcomes between these 2 modes of eccentric contraction have not been compared. The purpose of this study was to compare modes of contraction for differences in muscle damage. 16 men were placed in the isotonic (IT: 110% of maximal isometric torque) or the isokinetic (IK: 120°/s) group, with each group performing 200 eccentric muscle actions of the knee extensors. Isometric peak torque, perceived soreness and CK activity were measured immediately pre and post exercise, and 48-h post exercise. Mean total work (~1700 J) and peak torque per set (~265 Nm) decreased over the 200 repetitions (p<0.01), and was not different between groups. Damage markers changed 48-h post exercise (p<0.05): peak isometric torque (-13%), creatine kinase activity (+200%) and self-perceived muscular soreness (+4 unit change). Significant group×time interactions (p<0.01) indicated that peak isometric torque was 22% lower, and creatine kinase and self-perceived muscular soreness were 330% and 3 unit difference higher in the IT as compared to the IK groups, 48-h post exercise. When equating for total work, skeletal muscle damage markers are higher during IT vs. IK modes. This reflects differences inherent in contraction type and suggests that this should be taken into account during physical rehabilitation.

In situ process quality monitoring and defect detection for direct metal laser melting.

Quality control and quality assurance are challenges in direct metal laser melting (DMLM). Intermittent machine diagnostics and downstream part inspections catch problems after undue cost has been incurred processing defective parts. In this paper we demonstrate two methodologies for in-process fault detection and part quality prediction that leverage existing commercial DMLM systems with minimal hardware modification. Novel features were derived from the time series of common photodiode sensors along with standard machine control signals. In one methodology, a Bayesian approach attributes measurements to one of multiple process states as a means of classifying process deviations. In a second approach, a least squares regression model predicts severity of certain material defects.

Hepatocellular Carcinoma Cells Are Protected From Immunolysis by Mesenchymal Stromal Cells Through Indoleamine 2,3 Dioxygenase.

B7 family proteins serve as checkpoint molecules that protect tumors from T cell mediated lysis. Tryptophan degrading enzymes indoleamine 2,3 dioxygenase (IDO) and tryptophan 2,3 dioxygenase (TDO) also induce T cell immune tolerance. However, little is known about the relative contribution of B7 molecules, tryptophan degrading enzymes, as well as the impact of tumor and stromal cell interactions to the development of immunosuppressive tumor microenvironment. To investigate such interactions, we used a tripartite model of human hepatocellular carcinoma cell line (HepG2) and mesenchymal stromal cells (MSCs) co-cultured with peripheral blood mononuclear cells (PBMCs). Co-culture of HepG2 cells and activated PBMCs demonstrate that HepG2 cells undergo PBMC mediated cytolysis, despite constitutive expression of B7-H3 and upregulation of PD-L1 by IFNγ. Knockdown of B7-H3, PD-L1 or IDO does not modulate PBMC mediated lysis of HepG2 cells. However, TNFα preactivation enhances lysis of HepG2 cells, and blocking of TNFα production from PBMCs protects HepG2 cells. On the other hand, MSCs protect HepG2 cells from PBMC mediated lysis, even in the presence of TNFα. Further investigation showed that MSC mediated protection is associated with the unique secretome profile of upregulated and downregulated cytokines and chemokines. IFNγ activated MSCs are superior to TNFα activated or control MSCs in protecting HepG2 cells. Blockade of IFNγ driven IDO activity completely abolishes the ability of MSCs to protect HepG2 cells from cytolysis by PBMCs. These results suggest that inhibition of IFNγ activation of IDO induction in stromal cells, combined with usage of TNFα, could be a novel immunotherapeutic strategy to induce regression of hepatocellular carcinoma.

Suppression and immunotherapy of the guinea pig line 10 hepatocarcinoma mediated by heat-killed disrupted Mycobacterium bovis strain Bacillus Calmette-Guérin.

Heat-killed Mycobacterium bovis strain Bacillus Calmette-Guérin cells were sonically disrupted, and their antitumor effects against the line 10 hepatocarcinoma in strain 2 guinea pigs were evaluated. When injected together with viable line 10 cells, there was complete suppression of tumor growth. Growth of tumor was also suppressed when line 10 cells were injected contralaterally at the same time as the vaccine mixture. Multiple intratumor injections of sufficient disrupted M. bovis strain B. Calmette-Guérin were therapeutically effective against 74% of 7-day-old tumors and against 40% of 14-day-old tumors. Surviving animals were usually resistant to subsequent rechallenges with line 10 cells but not to syngeneic L2C leukemia cells. By means of a competitive radioimmunoassay, antigenic determinants were detected that were expressed by disrupted but not by intact bacteria.

Immunotherapy of the guinea pig line 10 hepatocarcinoma with a variety of nonviable bacteria.

A variety of heat-killed bacteria were tested for their capacity to induce regressions of established line 10 hepatocarcinomas in syngeneic guinea pigs. Multiple intralesional injections of heat-killed Escherichia coli, Streptococcus mutans, Listeria monocytogenes, and Propionibacterium acnes resulted in complete regression of the tumor in a majority of guinea pigs. Repeated injections of heat-killed Mycobacterium bovis strain Bacillus Calmette-Guérin caused no regressions. Surviving animals were immune to subsequent challenge with line 10 cells but not L2C cells, another syngeneic tumor.

Clinical results of Maverick lumbar total disc replacement: two-year prospective follow-up.

Disc prosthesis is the new treatment for degenerative disc disease in the lumbar spine. Key to assessing the interest in this new motion technique is evaluating the results in terms of functional and radiologic outcomes. This prospective study reports the outcome of 64 Maverick devices implanted between January 2002 and November 2003. The degree of improvement was equivalent to that obtained with anterior fusion cages using the mini-invasive technique. Radiographic follow-up in this series showed a degree of mobility close to normal. The technique is safe because the intra- and postoperative complication rate is low. The Oswestry score improved for 75% of patients. This improvement is significantly correlated with facet arthrosis and muscle fatty degeneration.

A quantitative radiometric assay to measure mammalian cell binding to hyphae of Candida albicans.

A rapid and reproducible assay has been developed to measure the capacity of lymphocytes to bind to Candida albicans. Lymphocytes that bound to C. albicans were either the large granular lymphocyte cell line, YT, or interleukin-2 activated lymphocytes. Lymphocyte binding was assessed as the associated radioactivity of 51Cr-labeled lymphocytes with preformed hyphae. The assay was sensitive to detection of 0.6 lymphocytes/one hyphal form at one half maximal lymphocyte binding capacity. The assay correlated well with direct microscopic assessment of lymphocyte binding to C. albicans and provided quantitative radiometric data. Although the assay was developed for the assessment of lymphocyte adhesion to C. albicans, it can be used to measure binding of other mammalian cells (e.g., polymorphonuclear leukocytes) to this fungus. In addition, the assay may be used to identify molecules involved in the adhesion of lymphocytes and other mammalian cells to C. albicans.

Quantitative measurement of lymphocyte mediated growth inhibition of Candida albicans.

A rapid and reproducible assay has been developed to measure the capacity of lymphocytes to inhibit the growth of Candida albicans. Fungal growth inhibition was assessed optimally as the incorporation of [3H]uridine into preformed hyphae, following interaction of the hyphae with effector lymphocytes. The assay was sensitive to the detection of fungal growth inhibition by lymphocytes at low effector to target ratios and results correlated well with other methods for measurement of anti-C. albicans growth inhibition in vitro. Although the assay was developed for the measurement of lymphocyte mediated anti-fungal activity, other mammalian cell populations can be assayed for growth inhibition of C. albicans as well. The described assay utilizes the enzyme lyticase to reduce the surface binding of C. albicans. The use of this enzyme permits the efficient harvest of large numbers of experimental samples with a multiple automated sample harvester.

Purification of antibodies to bacterial antigens by an immunoadsorbent and a method to quantify their reaction with insoluble bacterial targets.

A combination of procedures was employed to develop a radioimmunoassay which quantified the binding of antibodies to antigens of either intact Propionibacterium acnes or to antigens of insoluble extracts derived from the bacteria. Reactive antibody populations were purified by use of bacterial immunoadsorbents which were prepared by coupling P. acnes to diethylaminoethyl cellulose. Binding of antibodies was detected with [125I]staphylococcal protein A ([125I]SpA) and optimal conditions for the assay defined by varying the amounts of antibodies, bacterial antigenic targets and [125I]SpA. In antibody excess, 100% of available [125I]SpA was bound by the target-antibody complexes. However, when antibody concentration was limiting, a linear relationship was demonstrated between per cent specific binding of [125I]SpA and antibodies bound to bacterial targets. These results were achieved only with immunoadsorbent-purified antibody populations and not with hyperimmune sera or IgG. The radioimmunoassay detected subtle antigenic differences and similarities between P. acnes, P. acnes extracts and a variety of unrelated microorganisms.

Acetylcholinesterase in cultured human leukemia/lymphoma cell lines.

Fifty-two cultured leukemia/lymphoma cell lines were studied for their acetylcholinesterase activity. There was a striking effect of maturity on enzyme activity, only the most mature cells showing significant activity. Mature T cells exhibited far more enzyme activity than mature B cells, paralleling results on normal T and B cells.

Reduced levels of Hsp70 result in a therapeutic effect of 15-deoxyspergualin on acute graft-versus-host disease in (DA x LEW)F1 rats.

We have shown previously that increased levels of hsp70, and antibodies reactive with hsp70 parallel the onset and severity of graft-versus-host disease (GVHD) in a parent --> (DA x LEW)F1 rat model. In this study we have assessed the effect of reducing the levels of the 70 kDa heat shock protein (hsp70), on the morbidity and mortality of acute GVHD in (DA x LEW)F1 rats. The reduction was accomplished by the administration of 15-deoxyspergualin (DSG), an immunosuppressive agent which binds to a constitutively expressed member of the 70 kDa heat shock protein family. DSG administered via three different protocols reduced GVHD-associated morbidity. One of the regimens, which consisted of intermittent DSG administration, also significantly reduced GVHD associated mortality. This DSG treatment reduced hsp70 levels in spleen and lymph nodes, inhibited anti-hsp70 antibody production, and diminished the serum levels of IL-2, IFN-gamma, TNF-alpha, and IL-10. IL-4 levels in the serum did not change during GVHD and were not effected by DSG. These results show that the mechanism of DSG immunosuppressive effect in rat GVHD may involve DSG's capacity to bind to hsp70, which in turn may lead to a decrease in levels of circulating anti-hsp70 antibodies, and reduced production of cytokines.

A longitudinal study of malaria antibodies in a Malaysian population. I. Group responses.

The indirect hemagglutination test was used to measure malaria antibody levels in residents of an endemic area of Malaysia. Blood specimens were collected at 4-week intervals for a year. Seropositivity rates increased with age and number of episodes of malaria in young children. Although antibody levels were variable, titers tended to rise with parasitemia and fall in the absence of detected parasites. In general, the serologic indices tended to reflect the parasitologic findings.

A longitudinal study of malaria antibodies in a Malaysian population. II. Follow-up of individuals.

A cohort of 62 persons living in a malaria-endemic area was examined by serology and by blood film 14 times over a 56-week period. Serologic responses (indirect hemagglutination test) of the group as a whole reflected the malaria transmission as determined by blood slide examination. The serologic responses of individuals showed titer changes that were not always consistent with blood slide results. The use of chloroquine may have modified the host's immune response.

Duffy blood types and vivax malaria in Ethiopia.

We investigated an hypothesis relating the Duffy-negative blood type with insusceptibility to vivax malaria--and previously associated only with people of West African ancestry--in three population samples of eastern African stock. The samples included Nilotic and Hamitic-Semitic residents of a malarious locale in Ethiopia and Hamito-Semites in Addis Ababa where malaria is not endemic. Fresh red blood cells from 191 subjects were tested with Duffy antisera, anti-Fya and anti-Fyb. Duffy-positive rates in the malarious community were 8% for the Nilotes and 70% for the Hamito-Semites; the Hamito-Semites in Addis Ababa were 98% Duffy-positive. The relative prevalences of Plasmodium vivax in the two study groups at risk to malaria were 2.4% for the Nilotes and 27.3% for the Hamito-Semites, producing a ratio similar to the ratio of Duffy-positive in the two samples. We interpret the data as supportive of the Duffy-vivax hypothesis with reference to a part of eastern Africa, and we suggest that the Duffy-negative genotype may represent the original, rather than the mutant, condition in tropial Africa.

Plasmodium brasilianum antigen for use in the indirect hemagglutination test.

Antigen was prepared from Plasmodium brasilianum harvested from an infected spider monkey. This antigen was attached to aldehyde-fixed, human type O cells, and was tested against sera from human cases of P. malaria, P. vivax, P. falciparum, and P. ovale infection, and sera from noninfected persons. At dilutions of 1:16 or greater the antigen failed to react in sera from noninfected persons. It reacted at titers of 16 or above with sera from 85% of the persons with P. malariae infection, 83% with P. vivax infection, 70% with P. falciparum infection, and 70% with P. ovale infection.

Comparison of the complement fixation, indirect immunofluorescence, and indirect hemagglutination tests for malaria.

The complement fixation (CF), indirect immunofluorescence (IIF), and indirect hemagglutination (IHA)tests for malaria were compared by using sera from U.S. citizens with either natural infections or heroin-associated, needle-induced infections. In natural Plasmodium vivax infections, the CF, IIF, and IHA tests apparently detect malarial antibodies equally efficiently for the first 2 months after the onset of symptoms, but the titers obtained by CF and IIF rapidly decline within a year, while the IHA titers remain elevated. In the sera from heroin addicts who developed needle-induced P. vivax infections, sensitivities of all three tests were decreased: the IIF and IHA tests each detected 83%, but the CF test detected only 57.1%. False-positive reactions with this group were very high for the CF (76.6%) and IHA (15.9%) tests, but only 2% for IIF.

The indirect hemagglutination test for malaria. Evaluation of antigens prepared from Plasmodium falciparum and Plasmodium vivax.

Soluble antigens were prepared from Plasmodium falciparum and P. vivax and were evaluated in the indirect hemagglutination test. These antigens, attached to aldehyde-fixed type "O" erythrocytes, detected antibodies in more than 91% of infections with the homologous Plasmodium species. Detection rates in infections caused by the heterologous species ranged from 72% to 76%. Positive reactions occurred in less than 2% of sera from persons without malaria infection.

Malarial antibodies measured by the indirect hemagglutination test in West African children.

The indirect hemagglutination test with Plasmodium falciparum antigen was used to measure malarial antibodies in filter paper blood specimens from 527 West African children. A slight decline in antibodies was noted in 6- to 8-month-old children wh o had no malaria parasites in their blood smears. Children older than 10 months had similar antibody levels regardless of the presence or absence of demonstrated parasites in blood smears.

Serologic and parasitologic studies of Entamoeba histolytica in El Salvador, 1974-1978.

Serologic and parasitologic studies were done in El Salvador, C.A., from 1974-1978 to examine the reliability of the diagnosis of Entamoeba histolytica infection in an endemic area and to confirm the estimates of morbidity and mortality due to amebiasis. The results suggest that infection with E. histolytica is common, but the estimated prevalence is too high. Misdiagnosis occurring in hospital and public health laboratories was documented. Data collected from examining family members of persons with E. histolytica infection and disease indicate that most infections are asymptomatic, and support the hypothesis that estimates of morbidity and mortality rates are excessive.

Antifungal activity of interleukin-2-activated natural killer (NK1.1+) lymphocytes against Candida albicans.

Interleukin-2 (IL-2)-activated lymphocytes interact directly with, and inhibit, the growth of Candida albicans hyphae. C. albicans-stimulated natural killer (NK1.1+) lymphocytes were demonstrated to secrete a soluble product capable of directly affecting C. albicans yeast forms. Antibodies specific for interferon-gamma completely eliminated the antifungal activity of the NK1.1+ lymphocyte product and diminished the antifungal activity of NK1.1+ lymphocytes against C. albicans. Antibodies specific for other cytokines had no such effect. These data demonstrate that C. albicans-stimulated NK1.1+ lymphocytes have antifungal activity against C. albicans yeast cells via the release of interferon-gamma. This antifungal activity was demonstrable only against the yeast form of the fungus, with no effect on C. albicans hyphae.