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Biomedical subjects

T J Myers

Publications and source records attributed to T J Myers.

At least 19 recordsLinked to original sources
PubMed1992

Partial purification and characterization of chicken interleukin-2.

Chicken interleukin 2 (IL-2) activity was partially purified from conditioned medium produced by culturing chicken splenic lymphocytes in the presence of concanavalin A. The purification procedure included sequential steps of gel filtration chromatography, reverse-phase high-pressure liquid chromatography, and phenyl-sepharose chromatography. Two peaks of IL-2 activity with apparent mol. wt. ranges of 36-39 kD and 17.5-25 kD were eluted from the Sephadex G100 gel filtration column. An increase in IL-2 spec. act. from 14 U mg-1 to between 2000 and 20,000 U mg-1 was obtained for the Sephadex G100 column peaks when subjected to the subsequent steps of the purification procedure. Alkylative reduction of the higher mol. wt. Sephadex G100 column peak (followed by re-chromatography with Sephadex G100), resulted in generation of the lower (17.5 kD) mol. wt. peak, indicating that chicken IL-2 is capable of either dimerizing or forming aggregates with other proteins. Elution of the lower mol. wt. IL-2 activity from a non-reducing sodium dodecyl sulfate-polyacrylamide gel demonstrated an apparent mol. wt. for chicken IL-2 of 20 kD, which confirmed the range of 17.5-25 kD seen with gel filtration.

Alkylation↗
PubMed1991

Predictive value of the fluorescent cytoprint assay (FCA): a retrospective correlation study of in vitro chemosensitivity and individual responses to chemotherapy.

The potential clinical usefulness of the fluorescent cytoprint assay (FCA) was assessed retrospectively in 73 cancer patients by correlating individual tumor chemosensitivity in vitro with responses to chemotherapy. The data show that the FCA has a sensitivity of 98%, specificity of 81%, and predictive accuracies of 85% and 97% for positive and negative clinical responses, respectively.

Antineoplastic Agents↗
PubMed1990

Natural killer cell activity of chicken intraepithelial leukocytes against rotavirus-infected target cells.

Intraepithelial leukocytes (IEL) and splenocytes collected from uninfected and rotavirus-infected chickens were evaluated for cytotoxic activity against a natural killer (NK) cell-susceptible lymphoblastoid cell line (LSCC-RP9) and against rotavirus-infected chick kidney cells in 4-h chromium-release assays. Both splenocytes and IELs from uninfected and rotavirus-infected chickens were cytotoxic for LSCC-RP9, and the levels of this NK cell activity were not altered by infection of the host with rotavirus. IELs but not splenocytes from uninfected and rotavirus-infected chickens were cytotoxic for rotavirus-infected but not for uninfected chick kidney cell targets. Because this cytotoxic activity was not induced nor altered by rotavirus infection of the host, and was not major histocompatibility complex-restricted, it was considered to be due to NK cell activity. The cytotoxicity of IELs against rotavirus-infected target cells was dose-dependent; however, there was some suppression of cytotoxic activity at high effector to target cell ratios. There were no differences in the cytotoxic activities of IELs collected from the duodenum versus the jejunum. The in vitro cytotoxic activity of IELs against rotavirus-infected target cells suggested that NK cell activity may be an important immune response to rotavirus infections in vivo. The absence of cytotoxic activity by splenocytes against rotavirus-infected target cells indicated that there may be different subpopulations of NK cells in the spleen and intestinal epithelium of chickens.

Animals↗
PubMed1988

Implantation of balloon-expandable intravascular grafts by catheterization in pulmonary arteries and systemic veins.

The purpose of this investigation was to evaluate the efficacy and safety of implanting expandable intravascular stents in pulmonary arteries and systemic veins. Twenty-seven balloon-expandable grafts were placed in 13 mongrel dogs under anesthesia. A long sheath was introduced over a wire and catheter or dilator into the pulmonary artery or target vein. A collapsed stainless steel expandable mesh stent was placed over the balloon of an angioplasty catheter. The catheter with the mounted stent was advanced through the sheath. The stent expanded to the diameter of the balloon as the balloon was inflated, and remained expanded as the balloon was deflated. The stent was expanded further with a larger balloon in 11 instances. Eleven stents were placed successfully in pulmonary arteries (out of thirteen attempted), and 11 of 14 were installed in tributaries of the precava or postcava. Three inadvertent embolizations of the devices occurred. All three devices that embolized lodged in the pulmonary arteries and did not obstruct flow. Seven dogs were recatheterized at intervals ranging from 56 to 278 days. Twelve stents were patent and nonobstructive, and two were malpositioned, one of which was obstructed. Three animals were killed 2 months (two dogs) and 9 months (one dog) after the implantations. The stents (four in the pulmonary arteries and two in veins) were completely covered with neointima and were patent, without thrombosis. These stents hold promise for definitive dilation of congenital or postoperative vessel stenoses.

Animals↗
PubMed1988

Tensile strength of spinal ligaments.

Spinal ligaments from 41 fresh human male cadavers were tested. The ligaments were tested in situ by sectioning all elements except the one under study. The force deflection curves demonstrated a sigmoidal shape, and the point at which an increase in deflection was obtained with decreasing force was taken as failure. The force and deformation at failure are shown for each ligament as a function of spinal level.

Aged↗
PubMed1987

Cultivation of avian rotaviruses in chicken lymphocytes and lymphoblastoid cell lines.

Avian rotavirus isolates were used to infect normal chicken spleen cells, lymphoblastoid T cell lines transformed by Marek's disease virus, an avian leukosis virus-transformed B cell line, and a reticuloendotheliosis virus-transformed line, which is a pre-B, pre-T cell line. All five isolates tested were able to infect spleen cells and the three types of lymphoblastoid cell lines, suggesting that avian rotaviruses can infect both B and T cells. Splenic lymphocytes were considerably less susceptible to infection than chick kidney cells. Lymphoblastoid cell lines remained virus-positive during a 10-day culture period. Virus was neutralized by the addition of low dilutions of normal chicken serum and high dilutions of chicken anti-rotavirus serum.

Animals↗
PubMed1979

Hairy cell leukemia and sarcoid.

A 45-year-old female simultaneously developed both hairy cell leukemia and acute sarcoid. A defect in suppressor T lymphocytes which allowed an unrestrained B-cell proliferation manifested as both hairy cell leukemia and sarcoid is proposed.

Female↗
PubMed1979

Polycythemia vera and mesenteric arterial thrombosis. A disease association resulting from decreased platelet sensitivity to aspirin.

Recurrent mesenteric arterial thrombosis developed in a 56-year-old man with polycythemia vera (PV) despite therapy with heparin sodium, warfarin sodium, and standard doses of aspirin and dipyridamole. Platelet aggregation studies disclosed a normal response to aggregating agents in the presence of blood levels of aspirin that usually inhibit in vitro platelet aggregation. Increasing the in vivo dose of aspirin was associated with inhibition of in vitro platelet aggregation and, thereafter, arterial thrombosis did not recur. This case demonstrates that some patients with PV and arterial thrombosis may be refractory to standard doses of anticoagulants and platelet antiaggregating agents.

Aspirin↗
PubMed1978

Angioimmunoblastic lymphadenopathy: pleural-pulmonary disease.

A 48-year-old female with angioimmunoblastic lymphadenopathy is described. Her disease was complicated by pleuritic chest pain, an exudative pleural effusion and pulmonary infiltrates attributable to underlying pleural-pulmonary angioimmunoblastic lymphadenopathy.

Adult↗
PubMed1978

Pulmonary disease with chlorambucil therapy.

A 73-year-old female developed pulmonary disease during treatment with chlorambucil for polycythemia vera. Cough and dyspnea were prominent symptoms. A chest roentgenogram revealed interstitial fibrosis. The diffusing capacity was markedly reduced. Pathologic findings included alveolar lining cell dysplasia, interstitial round cell infiltrates and interstitial fibrosis. Resolution of the pulmonary symptoms and partial clearing of the fibrosis on chest roentgenogram followed discontinuation of the chlorambucil and institution of steroid treatment. Chlorambucil may cause pulmonary fibrosis similar to busulfan and cyclophosphamide and this may be a potential complication of all alkylating agents.

Aged↗
PubMed1978

Hemolytic anemia associated with heterograft replacement of the mitral valve.

The first case of overt hemolytic anemia following mitral valve replacement with a porcine heterograft is reported. Cardiac catheterization failed to reveal a paravalvular leak or valvular incompetence to account for the hemolysis. Red cell traumatization by the Dacron-covered Stellite ring and stent is suggested as the cause of hemolysis with the porcine heterograft.

Anemia, Hemolytic↗
PubMed1977

Consumption coagulopathy and microangiopathic hemolytic anemia with an axillo-femoral graft.

Consumption coagulopathy and microangiopathic hemolytic anemia occurred as a complication of insertion of an axillofemoral, preclotted dacron graft. Treatment with heparin followed by dipyridamole and aspirin normalized the hematologic and coagulation abnormalities over a two month period. The mechanism of consumption coagulopathy associated with prosthetic grafts is discussed and a possible role for treatment with antiplatelet agents is suggested.

Aged↗
PubMedDate not supplied

Human intraperitoneal response to a left ventricular assist device with a Ti-6AI-4V alloy surface.

The soft tissue reaction to long-term implantation of an intraperitoneal left ventricular assist device (LVAD) was investigated. The HeartMate 1000 (Thermo Cardiosystems, Inc., Woburn, MA) is a pneumatically driven blood pump with smooth titanium alloy (Ti-6AI-4V) outer surfaces that is placed intraperitoneally in the left upper quadrant and sutured to the anterior abdominal wall. It is being used currently as a bridge to cardiac transplant, which sometimes requires extended support times. We examined the tissue capsule that formed around the rigid circular pump housing of four LVADs (duration of implant: 61, 86, 128, and 153 days) for gross, histologic, immunohistochemical, and ultrastructural analysis. Immunostaining was performed using monoclonal and polyclonal antibodies against cytoskeletal tissue markers (vimentin, desmin, alpha-smooth muscle actin), T and B lymphocytes, carcinoembryonic antigen, factor VIII, and cytokeratins (CAM 5.2 AE1/AE3, 34 beta E12, and 35 beta H11). Direct fluorescent immunolabeling for fibrinogen was also performed to characterize cell and tissue type. Histologic analysis of the 3 to 4 mm thick capsule with white, glistening inner surfaces showed fibrovascular tissue with multipotential subserosal cells (MSCs), capillary endothelium, collagen, and a few mononuclear infiltrates. The immunohistochemical profile of the MSCs differed from myofibroblasts despite a morphologic similarity. Transmission electron microscopy revealed abundant rough endoplasmic reticulum and peripherally arranged myofilaments within the spindle shaped cells. It was hypothesized that capsule formation was initiated by fibrin deposition, followed by proliferation of MSCs and subsequent formation of fibrovascular tissue.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMedDate not supplied

Frequency and significance of infections in patients receiving prolonged LVAD support.

Infections in patients undergoing mechanical circulatory support as a bridge to transplant are associated with significant mortality and morbidity. To determine the frequency and effects of infection during such procedures, a retrospective analysis was done of 14 patients who received prolonged (greater than 14 days) support with the Heartmate left ventricular assist device (LVAD) (Thermo Cardiosystems, Inc., Woburn, MA). All patients were men (mean age, 44.3 years), and duration of LVAD support ranged from 19 to 233 days (mean, 98.1 days). During LVAD support, five patients had no infections, and, in the remaining nine patients, infections were most common in the respiratory tract, catheter tips, and urine. Four device related infections occurred in three patients, all of which were resolved with antibiotic therapy. All 14 patients underwent transplantations, and none of the operations was delayed because of infection. Eleven of the patients are long-term survivors (range of time after transplant, 7.5-37 months). Infections were not associated with mortality or significant morbidity in this group of patients.

Adult↗
PubMedDate not supplied

Extended support with a left ventricular assist device as a bridge to heart transplantation.

The Heartmate-1000IP, an intracorporeal, pneumatically activated, pulsatile left ventricular assist device (LVAD) with textured blood-contacting surfaces, is undergoing clinical evaluation as a bridge to heart transplantation (HTx). During a 3 year period (January 1988 to April 1991), the authors evaluated 12 patients who required extended LVAD support (greater than 30 days) while awaiting HTx. Duration of support ranged from 31 to 233 days (mean, 117 days). LVAD performance was excellent, with average pump flow indices of 2.5-3.5 L/min/m2. Long-term antithrombotic therapy consisted of dipyridamole and aspirin in all except one patient who received only low-molecular-weight dextran. After the initial recovery period, prothrombin and partial thromboplastin times returned to baseline levels. Plasma-free hemoglobin levels averaged less than 10 mg/dl. One patient is currently receiving support (91+ days); the 11 other patients underwent successful HTx, with follow-up ranging from 7 to 36 months. The authors' cumulative experience with this LVAD totals more than 1,506 days of support (greater than 4 years) without evidence of any thromboembolic episodes. These results suggest that this LVAD provides an effective bridge to HTx for extended periods.

Adult↗