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S McKenzie

Publications and source records attributed to S McKenzie.

At least 91 records · Page 5Linked to original sources
PubMed1990

Interstitial brachytherapy for malignant brain tumors: preliminary results.

The authors report their experience with interstitial brachytherapy in 46 patients with malignant brain tumors. Twenty-three patients received implants after external radiation for newly diagnosed malignant astrocytoma, as part of a randomized study (Group I). Eighteen patients received implants for recurrent malignant astrocytoma (Group II) and 3 for recurrent solitary cerebral metastasis from adenocarcinoma of the lung (Group III). Two additional patients received implants as part of their initial therapy for a radiation-induced malignant astrocytoma and a malignant fibrous histiocytoma. In all patients high-activity iodine-125 sources were implanted temporarily by a stereotactic technique. To date 50 patients have been entered in the randomized study with a maximum follow-up of 31 months. The small numbers and short follow-up preclude any conclusions regarding the efficacy of brachytherapy used as part of initial therapy. The median survival to date in the 23 patients in this group who received implants is 60 weeks. The median survival to date for the 18 patients who received implants for recurrent malignant astrocytoma is 44 weeks postimplant. Two of the three patients who received implants for recurrent solitary metastasis are alive at 41 and 49 weeks postimplant; a third died at 39 weeks postimplant. Significant complications attributable to interstitial brachytherapy have been observed in 10 of 46 patients (21.7%). A second operation for clinical and radiological deterioration was performed in 12 patients (26.1%) 8 to 105 weeks after brachytherapy. The authors conclude that interstitial brachytherapy is beneficial for selected patients with recurrent malignant astrocytoma and solitary recurrent metastasis.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1990

The Bain, ADE, and Enclosed Magill breathing systems. A comparative study during controlled ventilation.

The Enclosed Magill, Humphrey ADE and the Bain breathing systems are all used for controlled ventilation of the lungs. This study compares the three systems in vitro with a lung model and in clinical practice. No difference was observed, with ventilatory variables commonly used in clinical practice, between the Bain and the ADE, while significantly lower end-tidal carbon dioxide values were observed with the Enclosed Magill (about 7%). Lower fresh gas flows can be used under these circumstances to maintain normocapnia with the Enclosed Magill than either the Bain or the Humphrey ADE.

Adult↗
PubMed1990

Expression of Mycobacterium tuberculosis and Mycobacterium leprae proteins by vaccinia virus.

Eight Mycobacterium tuberculosis and M. leprae genes were inserted into the vaccinia virus genome by in vivo recombination. The resulting virus recombinants were shown to express five different M. tuberculosis proteins (71, 65, 35, 19, and 12 kDa) and three M. leprae proteins (65 and 18 kDa and a biotin-binding protein) by Western immunoblot analysis, radioimmunoprecipitation, or black-plaque assay. When injected into BALB/c mice, the recombinants expressing the M. tuberculosis 71-, 65-, or 35-kDa protein and the M. leprae 65-kDa protein or the biotin-binding protein elicited antibodies against the appropriate M. tuberculosis or M. leprae protein. These vaccinia virus recombinants are being tested for the ability to elicit immune protection against M. tuberculosis or M. leprae challenge in animal model systems. The recombinants are also useful in generating target cells for assays aimed at elucidating the cellular immune responses to mycobacterial proteins in leprosy and tuberculosis. Furthermore, the M. tuberculosis 65-kDa protein and four of the other mycobacterial proteins share homology with known eucaryotic and procaryotic stress proteins, some of which may play a role in autoimmunity.

Animals↗
PubMed1989

Detection of major histocompatibility complex class I-restricted, HIV-specific cytotoxic T lymphocytes in the blood of infected hemophiliacs.

Major histocompatibility (MHC)-restricted, human immunodeficiency virus type one (HIV-1)-specific, cytotoxic T lymphocytes (CTLs) were detected in the peripheral blood mononuclear cells (PBMCs) of HIV-1-infected individuals. Using a system of autologous B and T lymphoblastoid cell lines infected with recombinant vaccinia vectors (VVs) expressing HIV-1 gene products, we were able to detect HIV-1-specific cytolytic responses in the PBMCs of 88% of HIV-1-seropositive hemophiliac patients in the absence of in vitro stimulation. These cytolytic responses were directed against both HIV-1 envelope and gag gene products. The responses were resistant to natural killer (NK) cell depletion and were inhibited by monoclonal antibodies (MoAbs) to the T cell receptor, CD8 surface antigens, and MHC class I antigens, suggesting a classical MHC class I restricted, virus-specific CTL response.

Antibodies, Monoclonal↗
PubMed1989

Antigenic specificity of antibody-dependent cell-mediated cytotoxicity directed against human immunodeficiency virus in antibody-positive sera.

Antibody-dependent cell-mediated cytotoxicity (ADCC) specific for human immunodeficiency virus (HIV) has been described for HIV-infected individuals. To determine the antigenic specificity of this immune response and to define its relationship to the disease state, an ADCC assay was developed using Epstein-Barr virus-transformed lymphoblastoid cell line targets infected with vaccinia virus vectors expressing HIV proteins. The vaccinia virus vectors induced appropriate HIV proteins (envelope glycoproteins gp160, gp120, and gp41 or gag proteins p55, p40, p24, and p17) in infected lymphoblastoid cell lines as demonstrated by radioimmunoprecipitation and syncytia formation with c8166 cells. Killer cell-mediated, HIV-specific ADCC was found in sera from HIV-seropositive but not HIV-seronegative hemophiliacs. This HIV-specific response was directed against envelope glycoprotein but was completely absent against target cells expressing the HIV gag proteins. The ADCC directed against gp160 was present at serum dilutions up to 1/316,000. There was no correlation between serum ADCC titer and the stage of HIV-related illness as determined by T-helper-cell numbers. These experiments clearly implicated gp160 as the target antigen of HIV-specific ADCC activity following natural infection. Vaccines which stimulate antibodies directed against gp160, which are capable of mediating ADCC against infected cells, could be important for protection against infection by cell-associated virus.

Antibody-Dependent Cell Cytotoxicity↗
PubMed1989

Oligoclonal immunoglobulins in HIV infection.

We tested 150 patients infected with human immunodeficiency virus (HIV) for the presence of oligoclonal bands in serum, prompted by reports that these abnormal proteins may have prognostic significance. Sixty HIV-negative individuals from "at-risk" groups were tested along with 80 HIV-negative, healthy blood donors for the presence of these bands. All sera were tested by isoelectric focusing, because it is more sensitive for this purpose than more-conventional electrophoretic techniques. In the HIV-positive group, 61% of the sera had oligoclonal bands; in the HIV-negative "at-risk" group, 36% had bands. No bands were detectable in sera from the healthy blood-donor group. Some patients were also followed for differing periods throughout their infection, and changes in their oligoclonal banding patterns could not be correlated with disease progression. The fact that oligoclonal bands were found to be present without HIV infection in a substantial number of individuals from within the "at-risk" groups leads us to conclude that the presence of oligoclonal bands in HIV infection is of limited prognostic significance.

HIV Seropositivity↗
PubMed1989

Analysis of the individual and combined reactivities of monoclonal antibodies H25, H366, and MY9 with normal progenitor cells and blast cells from patients with acute myeloblastic leukemia.

Recently we reported that two monoclonal antibodies (MoAbs), H25 and H366, which react with human natural killer cells and monocytes, also react with normal in vitro colony-forming cells including granulocyte-monocyte colony-forming units (CFU-GM), erythroid burst-forming units (BFU-E), and erythroid colony-forming units and with leukemic blasts in preliminary testing of cells from patients with myeloid leukemias and T cell acute lymphocytic leukemia. In the present studies we examined the reactivities of MoAbs H25, H366, and MY9 (singly or combined) with the total leukemic cell population and the leukemic clonogenic cells (L-CFC) from 28 patients with acute myeloblastic leukemia. Using cytofluorography, we found the extent of expression of antigen H25 comparable to MY9 in the majority of patients, and both were more highly expressed than antigen H366. Incubation with H25 and H366 MoAbs simultaneously did not increase the number of positive cells over that seen when stained with H25 alone; however, the amount of antibody fluorescence intensity (FI) was increased. Leukemic cells simultaneously stained with MoAbs H25, H366, and MY9 displayed the highest number of positive cells and FI. Using magnetic beads coated with sheep anti-mouse IgG for depleting antibody-binding cells, greater than or equal to 90% of L-CFC were depleted by a combination of H25 and H366 MoAbs in 76% of AML cases tested as compared to 41% of the cases with MoAb MY9. Using a MoAb cocktail of H25, H366, and MY9, greater than or equal to 90% of L-CFC were depleted in 94% of cases tested, and greater than or equal to 99% of L-CFC were removed in 76% of the cases. Using the same depletion methods for normal bone marrow cells, a combination of anti-H25 and anti-H366 removed 90%, 98%, and 84% of CFU-GM, BFU-E, and multipotent colony-forming units (CFU-GEM), respectively, whereas the cocktail of H25, H366, and MY9 MoAbs removed 98%, 99.5%, and 97% of CFU-GM, BFU-E, and CFU-GEM, respectively. Incubation of H25 and H366-depleted bone marrow cells for 2 weeks in the presence of irradiated adherent cell layers from long-term marrow cultures generated CFU-GM and some BFU-E, as did H25, H366, and MY9-depleted marrow cells, although to a much lesser extent. Based on the overall data, combinations of H25, H366, and MY9 MoAbs and immunomagnetic beads conceivably might have therapeutic potential for ex vivo elimination of leukemic cells from AML remission marrows prior to autologous transplantation.

Adult↗
PubMed1989

Monoclonal antibody M195: a diagnostic marker for acute myelogenous leukemia.

Monoclonal antibody (mAb) M195 is a mouse IgG2a reactive with a myelomonocytic differentiation antigen found on early myeloid cells and monocytes. The reactivity of M195 with fresh hematopoietic neoplasms in the blood or bone marrow from 227 patients at Memorial Hospital was determined by flow cytometry. M195 was positive on 67% of 61 myeloblastic leukemias. Seventy percent of Tdt-negative ANLL and 30% of Tdt-positive ANLL were positive; 100% of CMMOL and 100% of CML in myeloblastic crisis or accelerated phase were positive. In contrast, M195 was positive on only 8% of 51 lymphoblastic leukemias and 1% of 70 other nonmyeloid samples. M195 binding did not correlate well with FAB classification of ANLL. The pattern of reactivity of M195 was similar but not identical to that of MY9 (CD33) on the same cases (83% concordance). Cross-blocking of M195 binding by MY9 and L4F3 (CD33) was demonstrated. M195 may bind to a different epitope on the same protein antigen. The presence of both MY9 and M195 positivity on a leukemia sample had a 98% specificity of diagnosing ANLL, which was greater than MY9 alone (88%) or M195 alone (92%). Assays of granulocytic-monocytic and erythroid colony-forming units showed M195 to be present on these hematopoietic progenitors. This pattern of reactivity of M195, together with its lack of reactivity with mature granulocytic elements or with adult tissues, make it a candidate for therapy of ANLL in vivo.

Animals↗
PubMed1988

A cause-specific hazard rate analysis of prognostic factors among 199 adults with acute lymphoblastic leukemia: the Memorial Hospital experience since 1969.

Results of a multivariable analysis of prognostic factors are reported for 199 previously untreated adults with acute lymphoblastic leukemia (ALL). These patients have long-term follow-up, and the probability of cure is estimated at approximately 35%. The cause-specific hazard rate analysis found lower rates of achieving complete remission (CR) in patients with WBC greater than 10,000/microL, AUL (undifferentiated) morphology, and older age. Since these patients required additional time to respond, fewer of them actually achieved CR. Characteristics directly associated with a higher rate of death during induction therapy due to severe bone marrow suppression were low serum albumin concentration (less than or equal to 3.5 g/dL), age greater than 50 years, acute undifferentiated leukemia (AUL) morphology, low Karnofsky performance status, and weight loss greater than 5%. Factors associated with a higher rate of relapse were WBC greater than 20,000/microL, non-T cell ALL, age greater than 60 years, Ph' + ALL, and time to achieve CR greater than 5 weeks. These criteria were used to identify patients at high risk of relapse. In addition, the predictive value of high WBC was found to disappear by 18 months of continuous CR. Finally, the rate of death following first relapse was higher in patients with a short first remission duration, high percentage weight loss at initial diagnosis, and older age. In summary, factors associated with a higher rate of death during attempted induction (ie, low albumin, high percent weight loss, and poor performance status) had no association with the patient's ability to remain relapse-free. Conversely, factors correlating with more extensive or resistant disease (ie, high WBC, null or B cell ALL, or Ph' + ALL) showed no association with the ability to tolerate therapy. Thus, a less toxic but more effective induction regimen is needed for patients with a poor clinical status, whereas a more intensive form of therapy appears warranted for patients presenting with more extensive or resistant disease.

Adult↗
PubMed1987

Effective tumor immunotherapy directed against an oncogene-encoded product using a vaccinia virus vector.

We have constructed a vaccinia virus recombinant that expresses the extracellular domain of the rat neu oncogene-encoded protein, a 185-kDa transmembrane glycoprotein termed p185. Strain NFS mice immunized with this recombinant virus developed a strong antibody response against the neu oncogene product and were fully protected against subsequent tumor challenge with neu-transformed NIH 3T3 cells. No tumor immunoprotection was found when recombinant virus-immunized mice were challenged with Ha-ras-transformed NIH 3T3 cells. These data indicate that immunization with a single oncogene-encoded antigen can fully and specifically protect animals against tumor cells bearing this antigen.

Animals↗
PubMed1986

Once daily theophylline in childhood asthma.

A new sustained-release theophylline preparation has been designed with the purpose of providing 24-hour protection against bronchospasm in asthmatics when given as a single dose. Fifteen children with moderate asthma completed a double-blind, placebo-controlled crossover trial of this product given once a day before bed. There was a significant fall in night symptoms (P less than 0.05), a rise in the mean early morning peak expiratory flow rate (PEFR) (P less than 0.01) and a fall in the number of mornings on which PEFR was less than 2 SD under the mean for height (P less than 0.01). An improvement in mean day symptom scores and evening PEFR was not significant. Thus we have shown that this product given once a day before bed is suitable for this way.

Asthma↗