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Biomedical subjects

M Nesbit

Publications and source records attributed to M Nesbit.

At least 37 records · Page 2Linked to original sources
PubMed1997

Expression of an antigen homologous to the human CO17-1A/GA733 colon cancer antigen in animal tissues.

The CO17-1A/GA733 antigen is associated with human carcinomas and some normal epithelial tissues. This antigen has shown promise as a target in approaches to passive and active immunotherapy of colorectal cancer. The relevance of animal models for studies of immunotherapy targeting this antigen in patients is dependent on the expression of the antigen on normal animal tissues. Immunohistoperoxidase staining with polyclonal rabbit antibodies to the human antigen revealed the human homologue on normal small intestine, colon and liver of mice, rats and non-human primates, whereas mouse monoclonal antibodies to the CO17-1A or GA733 epitopes on the human antigen did not detect the antigen. Polyclonal rabbit antibodies, elicited by the murine antigen homologue derived from recombinant baculovirus-infected insect cells, immunoprecipitated the antigen from mouse small intestine, colon, stomach, kidney and lung. The isolated recombinant murine protein bound polyclonal, but not monoclonal, antibodies to the human CO17-1A/GA733 antigen, and recombinant human antigen bound polyclonal antibodies elicited by the murine antigen homologue. Thus, the antigen homologue expressed by animal tissues is similar, but not identical, to the human antigen. These results have important implications for experimental active and passive immunotherapy targeting the CO17-1A/GA733 antigen.

Animals↗
PubMed1996

Carcinogenesis in human skin grafted to SCID mice.

To directly examine a multistage carcinogenesis model and the role of UV light in human tissues, we grafted human skin onto mice with severe combined immunodeficiency disease. We found that the maximum dose of UV radiation in the B range (UVB; 280-320 nm) tolerated by these grafts was 500 J/m2 three times weekly. One hundred fifty-one grafted mice were then randomized and observed for a median of 9 months in five groups: no treatment, chemical initiation alone, UVB as a complete carcinogen, initiation plus UVB promotion, and initiation plus UVB and phorbol ester promotion. Actinic damage and squamous atypia were found in grafts of all groups receiving UV treatment; unequivocal human squamous carcinomas developed in two of these. Species origin was verified by human-specific bisbenzimide staining and in situ hybridization for human-specific Alu segment. Overall basal proliferation, measured immunohistologically, was reduced in UV-treated grafts, but foci of hyperproliferation were seen in conjunction with the dedifferentiated expression of cytokeratins 1, 10 and 5, 8. Murine tumors also developed frequently, confirming the biological relevance of the carcinogenic strategies tested. These findings demonstrate that development of malignant human tumors can be experimentally accelerated in human tissue.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1995

Temperature increase during removal of incisal extensions on resin-bonded castings.

To assist seating or relocation of resin-bonded retainers on abutments, extensions of the cast framework can be incorporated and removed after cementation. There has been apprehension concerning the heat created during the grinding of these extensions, particularly if there is a substantial bulk of metal. This study recorded the elevation of temperature when cast incisal extensions were removed by grinding after cementation. A total of 20 retainers were waxed for 0.3 mm thickness, cast in a nickel-chrome alloy, and bonded in-vitro to an acid-etched natural tooth with composite resin cement. The temperature of the coronal dentin was measured while the tag was ground with a high-speed dental handpiece. The maximum temperature and mean temperature elevations that exceeded the resting temperature were recorded. A significant temperature rise was apparent when complete incisal wrapover framework extensions were reduced compared with the removal of fingerlike locating extensions. In conclusion, care should be exercised when the locating extensions of resin-bonded retainers are removed with high-speed dental handpieces.

Cementation↗
PubMed1995

A comparison of three wetting agents used to facilitate the pouring of dies.

This study compared the effect of a clinical surfactant and one of three laboratory surfactants used before pouring dies from elastomeric impression materials. A total of 154 impressions were recorded. Hydrosystem surfactant was used before the recording of 78 of these impressions. A total of 154 dies were poured with Wax-mate, Tensilab, or Hydrosystem surfactants and examined for surface voids by an examiner who was unaware which wetting agent was used. Six dies were grossly defective and discarded. When the Hydrosystem surfactant had not been used during impression recording there was no significant difference between Hydrosystem (mean 10.2 +/- 8.8 voids, n 25), Wax-mate (mean 13.1 +/- 14.4 voids, n 25), and Tensilab (mean 14.9 +/- 11.6 voids, n 21) surfactants when the dies were poured. When Hydrosystem surfactant was used during impression recording, there was no significant difference between the number of voids on dies produced with Hydrosystem (mean 3.8 +/- 3.9 voids, n 26), Wax-mate (3.9 +/- 3.3 voids, n 25), or Tensilab (3.7 +/- 4.9 voids, n 26) surfactants. However, each of the groups in which Hydrosystem surfactant was used before impression recording resulted in dies with significantly fewer voids than when it had not been used, independent of the surface wetting agent used in the pouring of dies (p < 0.05). To reduce the number of voids in laboratory dies, this in vitro study suggested that a topical surfactant should be used before an impression is recorded.

Analysis of Variance↗
PubMed1993

Ewing sarcoma of bone in infants and toddlers. A clinicopathologic report from the Intergroup Ewing's Study.

BACKGROUND: Nineteen patients with Ewing sarcoma of bone, each younger than 3 years of age at the time of initial presentation, are reported. These children represent an unusually young age group for documented Ewing sarcoma and represent 2.6% of all patients registered in the Intergroup Ewing's Sarcoma Study (IESS). METHODS: The diagnosis was made on combined histologic, clinical, and radiographic grounds and was supported by immunohistochemistry in nine patients and electron microscopic study in eight patients. Immunohistochemical studies showed no staining against neuro-specific enolase, chromogranin, or S-100 in any patients, and in only one in nine patients were results of such studies focally positive against Leu-7. RESULTS: The most marked clinical variation between this group of infants and the general IESS patient population was a striking predominance of female patients in the younger age group (P < 0.001). There was a trend toward more rib, pelvis, and proximal long bone tumors in the infants and toddlers. The overall survival rate of the infants was 56%, almost identical to the survival rates of the older children. All of the infants who died of disease did so within 4 years. Extended follow-up as long as 9.9 years has found no late deaths attributable to tumor. The most significant late complications of therapy included cardiotoxicity with cerebral embolization from the heart and a short lower limb secondary to radiation therapy. CONCLUSIONS: Ewing sarcoma must be considered in the differential diagnosis of small cell, round cell, and blue cell tumors in bone, even in infants and toddlers.

Bone Neoplasms↗
PubMed1993

Final height after treatment for childhood acute lymphoblastic leukemia: comparison of no cranial irradiation with 1800 and 2400 centigrays of cranial irradiation.

We analyzed growth and final heights in 127 patients (68 female patients) treated for childhood acute lymphoblastic leukemia. Central nervous system prophylaxis included either no cranial radiation therapy (CRT) (n = 38), irradiation with 1800 centigrays (cGy) (n = 36), or irradiation with 2400 cGy (n = 53). None of the patients received spinal irradiation. Mean (+/- SEM) age at diagnosis was 6.4 +/- 0.25 years, mean height standard deviation score (SDS) at diagnosis was 0.28 +/- 0.12, and mean age at final height was 18.26 +/- 0.19 years. The change in height SDS between diagnosis and achievement of final height was significant for all treatment groups: -0.49 +/- 0.14, no CRT; -0.65 +/- 0.15, 1800 cGy; and -1.38 +/- 0.16, 2400 cGy. Irradiated patients had a greater loss in height SDS compared with the nonirradiated patients (p < 0.01), and those treated with 2400 cGy CRT had a greater decrease in final height SDS than the patients treated with 1800 cGy (p < 0.01). Both younger age and female sex were significantly associated with a greater decrease in height SDS in the patients treated with CRT; girls < or = 4 years of age at diagnosis had a mean loss in height SDS that was more than twice that observed for others treated with the same dose of CRT. Thus, although modern regimens for acute lymphoblastic leukemia (no CRT or 1800 cGy CRT) appear overall to have only a modest impact on final height, patients, especially girls, treated with 1800 cGy CRT at a young age remain at risk for clinically significant growth failure.

Age Factors↗
PubMed1993

Donor and host influences in bone marrow transplantation for immunodeficiency disease and leukemia.

Bone marrow transplantation is an effective form of therapy for lethal immunodeficiency diseases and leukemia. Patients who are treated by bone marrow transplantation for these diseases have an improved outcome if treated early after diagnosis, before they have developed secondary complications. Recent advances in transplantation have allowed choices between several donor types. These alternative donor types are the subject of this analysis from the University of Minnesota. In these diseases, matched sibling donor bone marrow transplantation is the standard for comparison. In individuals with lethal immunodeficiencies (severe combined immune deficiency [SCID], Wiskott-Aldrich syndrome [WAS], Chédiak-Higashi syndrome [CHS]) who lack a sibling donor, unrelated transplantation has produced results that are almost equal to those of matched sibling transplants. Patients with high-risk acute lymphoblastic leukemia (ALL) who have received sibling or unrelated transplants have results that are superior to autologous donor transplants. In ALL, there is a need to use new therapies, eg, immunotoxins, to decrease the currently high relapse rate. In patients with acute myelogenous leukemia (AML) in first complete remission, results are excellent and comparable using related and autologous donors. Results in non-first-remission AML are inferior and do not differ if related, unrelated, or autologous transplants are used. In chronic myelogenous leukemia (CML), early survival results are superior using autologous and related transplants as compared with unrelated transplants.

Bone Marrow Transplantation↗
PubMed1992

Production of a functional monoclonal antibody recognizing human colorectal carcinoma cells from a baculovirus expression system.

The light and heavy chain cDNA of a murine monoclonal antibody (MoAb) with specificity for human colorectal carcinoma cells have been expressed separately, together, and as a dual construct in insect cells infected with recombinant baculoviruses. High levels of the MoAb were expressed under the control of the polyhedrin promoter. The antibody maintained its specific binding to human colorectal carcinoma cells and mediated lysis of these cells by human lymphocytes, monocytes, and murine macrophages, as determined in antibody-directed cellular cytotoxicity (ADCC) assays. The recombinant immunoglobulin (Ig), like its ascitic counterpart, did not mediate lysis by either human or rabbit complement. The expression of a recombinant antibody exhibiting both functional binding site and Fc region capacities shows that the baculovirus system could be employed in the production of therapeutic Ig.

Animals↗
PubMed1992

Plain radiographic predictors of survival in treated Ewing's sarcoma. IESS Committee.

We analyzed 16 radiographic features of primary Ewing's sarcoma in 342 patients from the IESS 7299 (Intergroup Ewing's Sarcoma Study) for prognostic significance. Of these, 3 features demonstrated a statistically significant relationship to survival: maximal tumor dimension, tumor location, and an appearance of honey-combing within the lesion. Those individuals with primary lesions centered in the pelvis, femur, or humerus had a worse survival rate than those with lesions centered elsewhere. Similarly, we observed an inverse relationship between the greatest dimension of the osseous portion of the lesion and survival. The radiographic finding of honeycombing also showed a statistical association with improved survival. However, this feature was observed infrequently, and its significance should be assessed further. Otherwise, no other feature that we analyzed showed any relationship to patient prognosis.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1992

Immunophenotype predicts radiation resistance in T-lineage acute lymphoblastic leukemia and T-lineage non-Hodgkin's lymphoma.

In the preclinical arm of our study, the radiobiologic features of primary malignant cells from newly diagnosed and relapsed T-lineage acute lymphoblastic leukemia/non-Hodgkin's lymphoma patients were analyzed using clonogenic assays. A marked heterogeneity existed relative to the intrinsic radiation sensitivity of clonogenic T-lineage ALL/NHL cells from 42 patients. The mean SF2 (surviving fraction at 200 cGy) and alpha values (initial slope of the survival curve) were 0.36 +/- 0.04, and 0.558 +/- 0.079 Gy-1. Fourteen cases had SF2 values of > or = 0.50 and alpha values of < or = 0.2 Gy-1, consistent with a marked intrinsic radiation resistance at the level of clonogenic leukemia/lymphoma cells. Of these 14 radiation resistant cases, 12 were CD3+. Furthermore, the SF2 and D0 values of the 28 CD3+ cases were significantly higher than the SF2 and D0 values of the 14 CD3- cases (SF2: 0.441 +/- 0.048 versus 0.189 +/- 0.045, p = 0.002; D0: 189.6 +/- 26.3 cGy versus 108.7 +/- 18.2 cGy, p = 0.047) and CD3+ cases had smaller alpha values than CD3- cases (0.454 +/- 0.087 versus 0.765 +/- 0.152, p = 0.06). Thus, clonogenic cells from CD3+ T-lineage ALL/NHL patients were more resistant to radiation than clonogenic cells from CD3- T-lineage ALL/NHL patients. In the clinical arm of our study, 33 T-lineage ALL/NHL patients received autologous bone marrow transplants during remission. Pretransplant conditioning consisted of total body irradiation combined with high dose chemotherapy. The expression of CD3 antigen predicted the outcome of relapsed T-lineage ALL/NHL patients undergoing autologous bone marrow transplantation following total body irradiation plus high dose chemotherapy. Overall, the Kaplan-Meier estimate and standard error of the probability of remaining in remission at 3.5 years was 11 +/- 9% with a median relapse-free interval of 102 days. The disease-free survival at 3.5 years was 8 +/- 7% with a median disease-free survival time of 96 days. Notably, the expression of CD3 antigen on T-lineage ALL/NHL cells correlated with the probability of relapse after bone marrow transplantation. While 16 of 19 CD3+ patients relapsed after bone marrow transplantation, only 3 of 8 CD3- patients relapsed. The Kaplan-Meier estimates and standard errors of the probability of remaining in remission at 1 year after bone marrow transplantation were 7 +/- 6% (median relapse-free interval = 74 days) for CD3+ patients (n = 19) and 63 +/- 17% for CD3- patients (n = 8) (p = 0.006).(ABSTRACT TRUNCATED AT 400 WORDS)

Cell Line↗
PubMed1991

Lymphomatous presentation of childhood acute lymphoblastic leukemia. A subgroup at high risk of early treatment failure.

Multivariate analyses of the clinical course of 1537 children with acute lymphoblastic leukemia (ALL) identified a subgroup which experienced short remission duration and a high incidence of extramedullary relapse. The patients differed from other ALL patients by the presence at diagnosis of two or more of a constellation of clinical and laboratory features: organomegaly or mass disease, E-rosette positivity, hemoglobin level greater than 10 g/dl, leukocyte count greater than 50,000/microliters, male predominance, and older age. This type of presentation of ALL is referred to as the "lymphoma syndrome" (LS) since such patients exhibit a pattern of several clinical and laboratory features which were observed repeatedly but in differing combinations, and some of which clinically resemble lymphoma. A subsequent database from 2231 patients was analyzed. Patients with a mediastinal mass, massive splenomegaly, or massive adenopathy, alone or in combination, had a worse outcome when the patient also had either leukocytosis, E-rosette-positive lymphoblasts, or a normal or near normal hemoglobin (Hb) level at diagnosis. Similarly, the above three laboratory features alone or in combination did not predict less than 40% disease-free survival (DFS) unless they were accompanied by at least one of the clinical features of mass disease. When at least one clinical feature and at least one laboratory feature were present, the overall DFS was 36% 6 years after diagnosis versus 64% for all other patients. The association of these features with poor prognosis remained significant after adjusting for the level of leukocyte count at diagnosis, age at diagnosis, and sex of the patients. Patients with this recurrent syndrome of features do not represent a homogeneous biologic entity but they constitute a subgroup of patients with ALL having a high risk of treatment failure using current therapies, including failure to achieve remission, early relapse, and increased frequency of relapse in extramedullary sites. They deserve early recognition at diagnosis and selection of treatment strategies appropriate for very high risk ALL.

Adolescent↗
PubMed1991

Spot-welded wire hooks as seating guides for resin-bonded castings.

A technique is described to assist in accurate positioning of cast metal, resin-bonded prostheses. The method is particularly useful for the recementation of castings but can also be used with new restorations. A piece of rectangular chrome alloy arch wire is annealed and spot-welded to the retainer. The wire is then adapted to lie over the incisal edge of the abutment tooth and forms a locating device during trying in and cementing of the restoration. The wire hook assists in the handling of the casting at chairside and is easily snapped off after cementation, leaving little finishing to be completed. The technique permits access to all of the marginal surfaces at cementation and offers certain advantages over existing alternative techniques.

Cementation↗
PubMed1990

Comparison of two total body irradiation regimens in allogeneic bone marrow transplantation for acute non-lymphoblastic leukemia in first remission.

Between November 1976 and December 1987, 84 patients with newly diagnosed acute non-lymphoblastic leukemia who had achieved complete remission underwent non T-cell depleted allogeneic bone marrow transplantation from Human Leukocyte Antigen-Mixed Lymphocyte Culture (HLA-MLC) matched sibling donors. The first 36 patients (November 1976-June 1983) were prepared with cyclophosphamide, 60 mg/kg/day, IV for 2 days and single fraction total body irradiation with 750 cGy at a dose rate of 26 cGy/minute (Group I). The next 48 patients (July 1983-December 1987) were prepared with similar chemotherapy, but received hyperfractionated total body irradiation with total 1320 cGy, 165 cGy twice a day at a dose rate of 10 cGy/minute (Group II). Patient characteristics between these two groups are similar except for the significantly older age distribution in Group II. Median follow-up of Groups I and II are 8 years and 11 months and 2 years and 3 months, respectively. The Kaplan-Meier relapse-free survival, survival, and relapse rates at 3 years are 56, 58, and 19% in Group I and 69 (p = 0.22), 77 (p = 0.07), and 10% (p = 0.37) in Group II. There is no difference in the incidence of interstitial pneumonitis, viral or idiopathic, engraftment rate, or incidence of graft versus host disease (GVHD) between these two groups. The fractionated total body irradiation treated group had significantly less nausea and vomiting. Multivariate analysis shows that total body irradiation regimen is not a significant factor in regard to relapse rate, relapse-free survival, and survival.

Adolescent↗
PubMed1989

Location of neutralizing epitopes on the fusion protein of Newcastle disease virus strain Beaudette C.

A panel of eight neutralizing monoclonal antibodies (MAbs) against the fusion (F) protein of Newcastle disease virus (NDV) has been shown to locate a major antigenic site on the basis of competitive binding assay and additivity index studies. Five epitopes (A1 to A5) have been located within this site on the F protein of the Beaudette C strain of NDV on the basis of cross-resistance plaque assays of MAb-resistant mutants raised against these MAbs. Epitopes A1, A4 and A5 are distinct; epitope A2 partially overlaps epitope A3. Nucleotide sequence analysis of the F genes of MAb-resistant mutants showed that each predicted single amino acid substitutions ranging from amino acid residues 157 to 171 for epitope A4 and at residues 72, 78, 79 and 343 for epitopes A1, A2, A3 and A5 respectively. These locations indicate that both the F1 and F2 fragments are involved in the formation of a single antigenic site and suggest the involvement of extensive protein folding in the active form of this F protein.

Amino Acid Sequence↗
PubMed1989

Effect of amino acid substitutions on glycosylation of the haemagglutinin-neuraminidase glycoprotein of Newcastle disease virus strain Beaudette C.

The nucleotide sequences of two monoclonal antibody-resistant mutant viruses predict changes from the wild-type in the number of potential glycosylation (Asn-X-Thr/Ser) in the mutant haemagglutinin-neuraminidase (HN) glycoproteins of the Beaudette C strain of Newcastle disease virus. The HN glycoproteins of these mutants, F5 and Z18, migrate either slower (F5) or faster (Z18) than that of the wild-type in SDS-PAGE. HN proteins synthesized in chick embryo fibroblasts following infection by either mutant or wild-type virus in the presence of tunicamycin (an inhibitor of glycosylation), comigrate on SDS-PAGE. These results confirm that the HN protein of the mutant virus, F5, has gained a glycosylation site at Asn(323)-Ser-Ser and that the conserved potential glycosylation site at Asn(481)-His-Thr is indeed glycosylated in the HN protein of the wild-type Beaudette C strain of Newcastle disease virus but is lost in that of the mutant virus, Z18.

Amino Acid Sequence↗