Biomedical subjects
Publications and source records attributed to C Sanders.
A patient with symptoms of sleep apnea syndrome had signs of congestive cardiac failure. A sleep study fulfilled the criteria for sleep apnea. Features of Cheyne-Stokes respiration coexisted. Management of the cardiac failure by weight loss principally due to diuretic use eliminated the symptoms of sleep apnea.
A 37 kDa protein in extracts of bovine aorta and equine platelets was observed on SDS-polyacrylamide gel electrophoretograms to react with polyclonal and monoclonal antibodies to rabbit skeletal troponin-T (TnT) by immunoblotting. Following purification by precipitation at pH 4.6 and several ion-exchange chromatographic steps, it has been identified as glyceraldehyde-3-phosphate dehydrogenase (G3PD) by amino acid analyses and NH2-terminal sequencing. By ELISA, the anti-troponin-T monoclonal antibody reacted with rabbit skeletal G3PD appreciably but 120-fold less specifically than with TnT. A cyanogen bromide fragment (CB2) of TnT (residues 71-151) reacted with the monoclonal antibody nearly as well as intact TnT. This cross-reactivity between G3PD and TnT can be ascribed to a weak homology in the amino acid sequences of the two proteins between residues 72-80 of TnT and residues 157-165 of G3PD. Other regions of limited sequence similarity in the two proteins are also present. We conclude that the identification of diffuse cytoplasmic indirect immunofluorescent staining observed with a monoclonal anti-TnT antibody in chicken gizzard muscle is probably attributable to cross-reactivity with G3PD.
The cytotoxic effect of daunorubicin, carminomycin, idarubicin and the major metabolite of idarubicin in man, 4-demethoxydaunorubicinol, was investigated in a human normal progenitor myeloid stem cell assay and in a human tumor stem cell assay. Against normal myeloid progenitor cells, idarubicin and carminomycin were equally potent; both agents were significantly (P less than or equal to 0.01) more potent than daunorubicin. Idarubicin was approx. 2.5 times more potent than 4-demethoxydaunorubicinol. Against malignant tumor cells, 50% cell kill after exposure to idarubicin was observed in four out 24 samples; this inhibition occurred at a drug concentration of 0.1 micrograms/ml. Two of the samples sensitive to idarubicin were also sensitive to 4-demethoxydaunorubicinol at a concentration of 0.1 micrograms/ml. Overall, idarubicin was active against two out of six ovarian carcinomas and against one out of three breast carcinomas. Our data confirm that 4-demethoxydaunorubicinol may play a role in the biological activity of idarubicin.
The antitumor effect of flavone acetic acid, LM975, and its diethylaminoethyl ester derivative, LM985, was studied in four human malignant cell lines [WiDr, a colon carcinoma; LICR (LON) HN-3, a tongue carcinoma; MCF7, a breast carcinoma; K-562, a leukemia] using a colorimetric assay based on the reduction of dimethylthiazol-2-yl-diphenyltetrazolium. The cell lines were exposed continuously for 4-6 days to drug concentrations ranging between 0.1 and 500 micrograms/ml. For LM975, the concentrations inhibiting the growth of the various cell lines by 50% were 200 +/- 10, 97 +/- 7, 171 +/- 16 and greater than 500 micrograms/ml for LICR (LON) HN-3, WiDr, MCF-7, and K-562, respectively. The corresponding concentrations for LM985 were 151 +/- 3, 36 +/- 4, 86 +/- 3 and 140 +/- 18 micrograms/ml, respectively. The difference between LM985 and LM975 was statistically significant for the WiDr and LICR (LON) HN-3 lines. We also evaluated the cytotoxic activity of the two agents on normal human marrow myeloid progenitor cells in a colony-forming assay. Continuous exposure to the drugs gave a dose-dependent inhibition. The concentrations inhibiting the growth by 50% were 76 +/- 31 micrograms/ml for LM975 and 134 +/- 41 micrograms/ml for LM985. One hour incubation with either compound had no toxic effect on the myeloid progenitor cells. In conclusion, LM975 and LM985 do not appear to have a specific cytotoxicity for tumor cells. Our results indicate that, in vitro, toxicity on bone marrow myeloid progenitor cells is concentration dependent. Considering the low plasma concentration found in man after i.v. administration of LM985, our observations correlate well with the absence of drug-induced myelosuppression in patients.
The in vitro evaluation of new antineoplastic agents has been advocated as a method of selecting drugs for Phase I-II trials in patients. This paper is an attempt to validate, in an unbiased manner, the so-called in vitro Phase II clonogenic assay with regard to its predictive power in the clinic. Breast and ovarian cancer were chosen because of the relatively large number of drugs clinically evaluated for these diseases; 298 patients were studied. For metastatic breast cancer 12 drugs, six clinically active and six inactive, were tested. It was found that in patients without prior chemotherapy, there is an association between results in vitro and in vivo. In metastatic ovarian cancer, 11 drugs, four of which are known to be clinically inactive, were studied. The same positive association was seen for patients without prior chemotherapy. The implications of these findings are discussed.
Eight patients with malignant gestational trophoblastic disease had CT of the pelvis as part of their staging before chemotherapy. CT appearance of the uterus fell into three major types: normal size with irregular areas of hypodensity, uniform enlargement with areas of hypodensity, and focal areas of enlargement with or without areas of hypodensity. Patients with the second and third types were much more likely to have distant metastases and to require hysterectomy for successful treatment. CT findings of tumor nodules in the parametrium or myometrium were confirmed in three of the four surgical specimens of the uterus available for correlation. Myometrial tumor nodules were seen as areas of focal enlargement or as irregular eccentric areas of hypodensity. In one patient, parametrial extension was seen as an enhancing mass adjacent to the uterus. CT may be accurate in defining the extent of myometrial and adnexal disease and may have prognostic and therapeutic value.
Metastatic calcification of the lung and heart can cause severe cardiopulmonary compromise and death. Although it is found in most end-stage renal disease patients at autopsy, it is only rarely detected during life. Using a prototype dual-energy digital chest radiographic unit, we measured calcium content (mg/cm2) over the lung and heart in 32 hemodialysis patients. Pulmonary calcium content was significantly greater in these patients than in sex-matched control subjects (men, 230 +/- 43 [mean +/- standard error] vs 166 +/- 7, p less than .05; women, 168 +/- 19 vs 110 +/- 7.5, p less than .001). Abnormal values were detected by dual-energy radiography in 44% of patients (vs 9% of patients studied by conventional radiography). Cardiac calcium content was also significantly greater in the hemodialysis patients than in the control subjects (259 +/- 14 vs 184 +/- 8, p less than .05). Metastatic calcification was significantly correlated with elevated phosphate and calcium-phosphate product levels. Patients with significantly elevated pulmonary calcium content had evidence of restrictive lung disease by functional testing. There was an inverse correlation between elevated cardiac calcium content and ejection fraction. We conclude that dual-energy digital radiography allows premortem diagnosis of metastatic visceral calcification and is more sensitive than current techniques.
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We describe a 38-year-old male with abrupt onset of left hip pain. The diagnosis of transient osteoporosis of the hip was made on the basis of the clinical history and characteristic radiographic changes (osteopenia with indistinctness of the subchondral cortex). Magnetic resonance imaging demonstrated diffuse decreased signal in the proximal femur without localization to the femoral head and magnetic resonance findings were more obvious than those demonstrated by conventional radiographs. Radiographs and magnetic resonance imaging after cessation of symptoms were near normal. Magnetic resonance imaging may be helpful in evaluation of patients with acute hip pain.
Unmodified chicken gizzard tropomyosin (TM) has been fractionated into its two major isoforms beta and gamma, by chromatofocussing in the presence of 9 M urea and dithiothrieitol. Treatment of the native protein with several bifunctional N-hydroxysuccinimide esters gave the beta gamma-heterodimer as the major cross-linked product. A comparison of the thermal transition profiles of the two homodimers and of the native unfractionated TM also indicated the predominance of the beta gamma-heterodimer in the native protein. This conclusion is consistent with the absence of excimer fluorescence in pyrene-labeled gizzard TM and the relative resistance of the molecule to intramolecular disulfide formation (Lehrer, S.S., Betteridge, D.R., Graceffa, P., Wong, S., and Seidel, J. C. (1984) Biochemistry 23, 1591-1595) since the single cysteines on each of the two isoforms are widely separated. We conclude that further experimental evidence is required to assess the possibility that the gizzard TM is more rigid in its conformation than are those of the skeletal and cardiac proteins.
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The activity of menogaril and its major metabolite in animals and humans, N-demethylmenogaril, has been investigated in the human stem cell assay as developed by Salmon et al. Among 31 evaluable samples, four were sensitive to menogaril, including one which responded to N-demethylmenogaril. Three samples resistant to menogaril responded to N-demethylmenogaril. None was sensitive to doxorubicin. Overall, one out of seven ovarian samples and one out of three breast samples responded to menogaril. Our data confirm the in vitro activity of menogaril in ovarian and breast cancer; in addition, they suggest incomplete cross-resistance between doxorubicin and menogaril and, considering the concentrations of N-demethylmenogaril in animals and humans, a minor role for this metabolite in the overall antitumor activity of the parent compound.
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Chicken gizzard muscle tropomyosin has been fractionated into its two major components, beta and gamma and the amino acid sequence of the gamma component established by the isolation and sequence analysis of fragments derived from cyanogen bromide cleavage and tryptic digestions. Despite its much slower mobility on sodium dodecyl sulfate-polyacrylamide electrophoretic gels, it has the same polypeptide chain length (284 residues) as the alpha and beta components of rabbit skeletal muscle. Evidence for microheterogeneity of the chicken gizzard component was detected both on electrophoretic gels and in the sequence analysis. The gamma component is more closely related to rabbit skeletal alpha-tropomyosin than to the beta component. While the protein is highly homologous to the rabbit skeletal tropomyosins, significant sequence differences are observed in two regions; between residues 42-83 and 258-284. In the latter region (COOH-terminal) the alterations in sequence are very similar to those seen in platelet tropomyosin when compared with the skeletal proteins.
Chicken gizzard beta-tropomyosin has the same chain length (284 residues) as other muscle tropomyosins, and is most closely related to the beta component of rabbit skeletal muscle. The majority of the amino acid substitutions are restricted to two regions of the structure, residues 185-216 and 258-284. The altered sequences at the COOH-terminal ends (residue 258-284) of the two gizzard components are very similar to each other and to those in platelet tropomyosin and can be correlated with the reduced affinity of interaction of all three tropomyosins with skeletal troponin T and its T1 fragment. The virtually identical NH2-terminal sequences of all four muscle tropomyosin chains indicates that the gizzard proteins' greater ability to polymerize head-to-tail is due to the sequence changes at its COOH terminus. On the other hand, the weaker head-to-tail aggregation of the platelet protein must be due to its NH2-terminal sequence alterations. Examination of the distribution of amino acids and the frequency of their substitution in the a to g positions of the repeating pseudoheptapeptide for all five tropomyosin sequences (four muscle and one platelet) emphasizes the importance of Glu residues at position e. Examination of those features of the muscle sequences implicated in the stabilization of their coiled-coil structures and in their interactions with F-actin suggest only marginal differences among them, with the possible exception of the chicken gizzard gamma component.
The anticancer activity of ametantrone was investigated in a human tumor cloning assay. Tumor samples were freshly obtained from 105 patients. Cells were exposed for 1 hr to drug concentrations of 1 and 10 micrograms/ml. A reduction in the number of tumor colony-forming units by 50% or more was seen in 2/31 breast cancers, 2/25 ovarian cancers, 1/10 primaries of unknown origin, 1/10 melanomas, 2/8 non-small cell lung cancers, 1/5 small cell lung cancers and 1/3 colon cancers. Only three of these in vitro responses were consistently obtained at the probably more relevant concentration of 1 microgram/ml. These findings indicate that low efficacy should be expected in cancer patients with ametantrone. The predictive value of these in vitro phase II data remains to be demonstrated.
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