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Biomedical subjects

M T Shaw

Publications and source records attributed to M T Shaw.

At least 19 recordsLinked to original sources
PubMed2005

Influence of temperature and aging time on HA synthesized by the hydrothermal method.

The influence of temperature and aging time on the morphology and mechanical properties of nano-sized hydroxyapatite (HA) synthesized by a hydrothermal method is reported here. The pre-mixed reactants were poured into a stirred autoclave and reacted at temperatures between 25-250 degrees C for 2-10 h. HA powders thus obtained were examined using X-ray diffraction (XRD), high-resolution field emission scanning electron microscopy (FESEM) and a particle size analyzer. It was found that the aspect ratio of the particles increased with the reaction temperature. The length of the HA particles increased with the reaction temperature below 170 degrees C, but it decreased when the temperature was raised above 170 degrees C. The agglomerates of HA particles were formed during synthesis, and their sizes were strongly dependent on reaction temperatures. As the reaction temperature increased, the agglomerate size decreased (p = 0.008). The density of the discs pressed from these samples reached 85-90% of the theoretical density after sintering at 1200 degrees C for 1 h. No decomposition to other calcium phosphates was detected at this sintering temperature. A correlation existed (p = 0.05) between the agglomerate sizes of HA particles synthesized at various conditions and their sintered densities. With the increase of the agglomerate size, the sintered density of the HA compact decreased. It was found that both the sintered density and flexural strength increased with increasing aging time and reaction temperature. A maximum flexural strength of 78 MPa was observed for the samples synthesized at 170 degrees C for 5 h with the predicted average at these conditions being 65 MPa. These samples attained an average sintered density of 88%.

Crystallization↗
PubMed1989

Cutaneous Hodgkin's disease in a patient with human immunodeficiency virus infection.

A 22-year-old man with human immunodeficiency virus infection had skin nodules of the chest wall. When a biopsy was performed on these nodules, Hodgkin's disease was discovered. The patient was subsequently found to have widespread disease involving the lymph nodes and liver. Skin involvement with Hodgkin's disease is rare. In this report, we review previous descriptions of skin involvement appearing in the literature.

Acquired Immunodeficiency Syndrome↗
PubMed1987

5-Fluorouracil, doxorubicin, and mitomycin-C in the treatment of adenocarcinoma and large cell carcinoma of the lung.

Fifty-four patients with adenocarcinoma and large cell carcinoma of the lung, 16 with localized surgically resected disease and 38 with metastatic disease, were treated with 5-fluorouracil, doxorubicin, and mitomycin-C (FAM), in an attempt to prolong previously reported survival times in the patients. The postsurgical patients were given elective chemotherapy. Eighteen received radiation therapy for control of local disease. Tumor regression, attributable to chemotherapy alone, was noted in ten of 20 cases in whom there was measurable disease. The median survival time of all patients was 32 weeks, ranging from 25 weeks in those with distant metastases to 56 weeks in patients with surgically resected disease. FAM did not seem to produce any beneficial survival advantages.

Adenocarcinoma↗
PubMed1986

Oat cell carcinoma of the esophagus: unusual radiological appearances.

Primary oat cell carcinoma of the esophagus is a very rare tumour. The radiographic appearance of the three cases described in this paper are unusual because they resemble benign lesions such as leiomyoma, fibrous polyp and candidiasis. It would be interesting to investigate whether such an unusual appearance is common for this neoplasm.

Aged↗
PubMed1981

Clinical trials with diglycoaldehyde (NSC-118994): review and reasons for withdrawal from clinical trial.

All Phase II studies with diglycoaldehyde with leukemia and solid tumors have been reviewed. The dose schedules employed ranged from 1.5 to 2.0 g/m2/day for 3 to 5 days. The most common side effects have been gastrointestinal (nausea and vomiting), which occurred in 22% of the patients. Renal toxicity (rise in BUN, creatinine, and urinary proteins) was seem in 17% of the patients treated. Other infrequent toxicities include hypocalcemia (9%) and local complications such as phlebitis. Leukopenia, thrombocytopenia, positive Coombs' test and impairment in coagulation profile were also reported. In contrast to the hints of therapeutic efficacy described during Phase I trials, in phase II trials no activity was noted among 96 patients with solid tumors and only minimal antileukemic action among 49 other patients. These disappointing Phase II trials coupled with prominent toxicities have prompted the decision to terminate further clinical testing. This report summarizes all clinical observations as an example of circumstances which curtail clinical testing of anticancer drugs.

Aldehydes↗
PubMed1980

Monocytic leukemias.

The monocytic leukemias may be subdivided into acute monocytic leukemia, acute myelomonocytic leukemia, and subacute and chronic myelomonocytic leukemia. The clinical features of acute monocytic and acute myelomonocytic leukemias are similar and are manifestations of bone marrow failure. Gingival hypertrophy and skin infiltration are more frequent in acute monocytic leukemia. Cytomorphologically the blast cells in acute monocytic leukemia may be undifferentiated or differentiated, whereas in the acute myelomonocytic variety there are mixed populations of monocytic and myeloblastic cells. Cytochemical characteristics include strongly positive reactions for nonspecific esterase, inhibited by fluoride. The functional characteristics of acute monocytic and acute myelomonocytic cells resemble those of monocytes and include glass adherence and phagocytoses, the presence of Fc receptors for IgG and C'3, and the production of colony stimulating activity. Subacute and chronic myelomonocytic leukemias are insidious and slowly progressive diseases characterized by anemia and peripheral blood monocytosis. Atypical monocytes called paramyeloid cells are characteristic. The drugs used in the treatment of acute monocytic and acute myelomonocytic leukemias include cytosine arabinoside, the anthracyclines, and VP 16-213. Drug therapy in subacute and chronic myelomonocytic leukemias is not usually indicated, although VP 16-213 has been claimed to be effective.

Adult↗
PubMed1980

Phase I clinical studies with WR-2721.

Toxicity studies of S-2-(3 aminopropylamino)-ethylphosphorothioic acid (WR-2721) access patients in remission following radiation therapy. The dose has been escalated from 25 to 250 mg/m2 without significant symptoms. Inconsistent variation in the systolic blood pressure in some patients has been observed over an 8-10-point range without producing any symptoms. The variation could be within the patient's normal range. However, tests are planned to rule out cardiac toxicity or peripheral vascular reaction. Combining WR-2721 with conventional radiotherapy is contemplated by intravenous injection of the drug 20-30 minutes before irradiation. This will start as weekly injections, and the number of weekly injections will be increased progressively. Animal studies suggest that the level already safely reached could give significant protection to the normal tissues without protecting tumor.

Amifostine↗
PubMed1979

Reinduction therapy for adult acute leukemia with adriamycin, vincristine, and prednisone: a Southwest Oncology Group study.

In an attempt to improve remissions and survivals in previously treated patients with adult acute leukemia, we gave Adriamycin, vincristine, and prednisone for induction therapy, followed by 6-mercaptopurine and methotrexate for maintenance therapy to patients attaining complete remission (CR). The study group consisted of 18 patients with acute myeloblastic leukemia (AML), ten with acute lymphoblastic leukemia, and one with acute undifferentiated leukemia. Only one patient had previously received Adriamycin. Overall, there were ten CRs and two partial remissions. The five CRs and one partial remission in patients with AML occurred among those with one prior induction attempt; none of the eight AML patients with more than one prior induction attempt responded. The actuarial median duration of CR was 15 weeks and was similar for AML and acute lymphoblastic leukemia patients. Responders had a longer median survival (30 weeks) than nonresponders (9 weeks). Thus, although a reasonable number of responses in previously treated patients were obtained with this program, improvements in maintenance therapy are clearly needed.

Antineoplastic Agents↗
PubMed1978

Academic arrogance.

Explore the source record for details and available documents.

Attitude of Health Personnel↗
PubMed1978

The distinctive features of acute monocytic leukemia.

Acute monocytic leukemia is an uncommon form of acute leukemia. Distinctive clinical features include gingival hypertrophy, lymphoadenopathy, coagulation disorders, and lysozymuria. Blast cell morphology and cytochemistry are diagnostic. Receptors for the Fc fragment of IgG have been demonstrated on the basis of a few cases. The drug VP 16-213 has been shown to be very effective in treatment of untreated and previously treated patients.

Blood Coagulation Disorders↗
PubMed1978

B-cell leukemia-lymphoma with striking resemblance to Burkitt lymphoma in a 70-year-old woman.

A 70-year-old woman developed acute leukemia and a serum IgM spike. She entered complete remission with an adriamycin, vincristine, cytosine arabinoside, and prednisone combination. Bone marrow remission was maintained with intermittent cytosine arabinoside; however, she developed large skin nodules which partly remitted following adriamycin, vincristine, cyclophosphamide, and prednisone combination. They very rapidly recurred, and she died soon after. Autopsy revealed extensive tumor in the abdomen, pelvis, and thoracic cavity, but no bone marrow involvement. Histology revealed a "starry sky" appearance. Cytology showed undifferentiated cells with vacuolated cytoplasm resembling Burkitt lymphoma cells. Peroxidase and esterase stains were negative. There was strong pyroninophilia and the periodic acid-Schiff reaction showed granular activity in the cytoplasm. Electron microscopic appearances also resembled Burkitt lymphoma. Cytogenetic studies were normal, with no Ph1 chromosome. Immunofluorescence demonstrated surface IgM and a little IgA. 3H-thymidine incorporation was high, indicating rapid growth. Dibutyral cyclic adenosine monophosphate (cAMP) stimulated growth, which was further evidence of the lymphoid origin of the tumor. The close resemblance of this tumor to Burkitt lymphoma emphasizes the difficulties in systematically classifying the lymphomas.

Acute Disease↗
PubMed1978

Terminal deoxyribonucleotidyl transferase activity in B-cell acute lymphocytic leukemia.

Moderately high levels of activity of the enzyme terminal deoxyribonucleotidyl transferase (TdT) were found in the leukemic cells of a patient with acute lymphyocytic leukemia. The proliferating cells were B lymphocytes bearing IgG antibody, and the disease was associated with an IgG monoclonal spike and a mediastinal mass. The observations in this case suggest that TdT is related more to the immaturity and proliferation of certain lymphoid stem cells than to their progress toward B- or T-cell differentiation.

Adolescent↗
PubMed1977

Accidental poisoning in children: a psychosocial study.

Fifty pre-school children thought to have ingested potentially poisonous substances were studied, together with 50 controls. An interview of each child and mother was undertaken in the home situation. Seven at-risk factors make a child more likely to ingest a toxic substance. These are: greater accommodation changes by the family, father having had a large number of jobs, paternal past history of accidents, child's exploring ability, child's past history of poisonings, an abnormal appetite in children older than two years old and lower stimulation indices in 2-5 year-olds. Attention is drawn to the similarity between many of these factors and childhood abuse and neglect.

Accidents, Home↗