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Biomedical subjects

D Green

Publications and source records attributed to D Green.

At least 307 records · Page 17Linked to original sources
PubMed1986

Ultrasonography in the jaundiced infant: a new approach.

Diagnostic ultrasonography plays a major role in the evaluation of jaundiced infants. Seventeen such infants were studied in both fasting and post-prandial states. The gallbladder and biliary tract were evaluated to define features most useful in distinguishing children with biliary atresia from those with other causes of jaundice. Demonstration of a decrease in gallbladder size following feeding virtually eliminates the diagnosis of biliary atresia, even in children with abnormal HIDA scans.

Bile Ducts↗
PubMed1986

Antitumor activity and bone marrow toxicity of aminoglucose mustard anticancer agents in mice.

In previous structure-activity studies, we have demonstrated that attachment of a glucose molecule to the chloroethylnitrosourea cytotoxic group produces a compound with reduced murine bone marrow toxicity and retention of full antitumor activity. To further define this protective role conferred by the glucose moiety in bone marrow cells, we have replaced the nitrosourea cytotoxic group with another class of alkylating agent, a bifunctional nitrogen mustard. In a detailed structure-activity analysis, we have now characterized four analogues, with the mustard cytotoxic group positioned at carbon 2 [1,3,4,6-tetra-O-acetyl-2-(di-2-chloroethyl)amino-2-deoxy-D-glucopyranos e (TGM)], carbon 6, or carbon 1 (D- and L-isomers) of the aminoglucose molecule. On a molar basis, TGM was most toxic to normal BALB/c X DBA/2 F1 mice, with a 10% lethal dose (LD10) of 3.8 mumol/kg. The D- and L-isomers of 2,3,4,6-tetra-O-acetyl-N,N-bis(2-chloroethyl)glucopyranosylamine (C-1) were the least toxic, with an LD10 of 73 mumol/kg for both. Optimal antitumor activity against the murine P388 leukemia (single i.p. administration of the LD10) did not differ significantly among the four analogues, with increased life span ranging from 83-86%. P388 antitumor activity for nitrogen mustard (HN2) was significantly less, 60% increased life span (P = 0.01), while p-di(2-chloroethyl)amino-L-phenylalanine produced an increased life span of greater than 101%. An LD10 of 6-bis-(2-chloroethyl) amino-6-deoxy-D-glucose (C-6) or TGM produced significantly less depression of WBC counts than did an equitoxic dose of the C-1 isomers, HN2, or p-di(2-chloroethyl)amino-L-phenylalanine. The mean nadir WBC count for C-6 equaled 86% of control, and for TGM, 80% of control. Consistent with this sparing effect on the peripheral WBC, C-6 and TGM produced significantly less in vivo murine bone marrow DNA synthesis depression, 77 and 64% of control, respectively, as compared to the depression nadir produced by HN2 (27% of control), the D-isomer of C-1 (17%), the L-isomer of C-1 (18%), and p-di(2-chloroethyl)amino-L-phenylalanine (2%). These structure-activity studies demonstrate that conjugation of the mustard cytotoxic group to carbon 6 or carbon 2 of glucose produces an analogue that retains P388 antitumor activity significantly greater than that of HN2, with a concomitant reduction in murine bone marrow toxicity.

Amino Sugars↗
PubMed1985

In vitro studies of a new synthetic thrombin inhibitor.

(2R, 4R)4-methyl-1-[N alpha-(3-methyl-1,2,3,4-tetrahydro-8-quinoline- sulfonyl)-L-arginyl]-2-piperidine carboxylic acid monohydrate (MCI-9038) was found to be a potent synthetic inhibitor of thrombin. In concentrations as low as 1 microM, the thrombin time, prothrombin time, and partial thromboplastin time were more than doubled. The venom (Bothrops atrox) time was similarly prolonged. The drug also inhibited the thrombin-induced activation of factors VIII and XIII. While MCI-9038 in concentrations of 10(-4) M had no effect on platelet aggregation induced by collagen, ADP, epinephrine, and arachidonate, nanomolar concentrations inhibited thrombin-induced platelet aggregation and the release of platelet ADP. The drug also significantly inhibited the adhesion of thrombin-treated platelets to cultured bovine aortic endothelial cells. We conclude that MCI-9038 is an extremely potent inhibitor of the effects of thrombin on platelets and clotting factors.

Arginine↗
PubMed1985

The bleeding time as a preoperative screening test.

To examine the benefit of determination of the bleeding time as a preoperative screening test, the medical records of all patients who had a prolonged bleeding time during a six-month period were reviewed. At Northwestern Memorial Hospital, where the bleeding time test is part of the presurgical panel, 1,941 bleeding time determinations were performed during six months. Prolonged bleeding times were recorded in 110 preoperative patients, of whom 83 (75 percent) had bleeding risk factors, including drug ingestion, thrombocytopenia, and azotemia. In these patients, the bleeding time ranged unpredictably from 10 to more than 20 minutes. However, of the 27 patients without apparent risk factors, only two had bleeding times of more than 20 minutes. This small number probably does not justify the routine use of the test in all preoperative patients. Rather, the test should be used selectively for those subjects who, on the basis of history or laboratory evidence, are suspected of being at risk of hemorrhage. Moreover, even in these patients, prolongation of the bleeding time may not always be associated with excessive surgical blood loss.

Aspirin↗
PubMed1985

Initial intravenous cis-platinum therapy: improved management for invasive high risk bladder cancer?

Between August 1981 and December 1983, 50 patients with invasive high risk bladder cancer were treated initially with 100 mg. per m.2 cis-platinum intravenously in 2 doses with a 3-week interval, which was followed by definitive treatment (radiotherapy and/or cystectomy). High risk disease was defined on the basis of at least 2 of the following: invasion into or beyond the muscle (stages B2 to D1), grade III histology, large tumors and ureteral obstruction. Major symptomatic improvement was noted in 38 patients (76 per cent) after 1 to 2 doses of cis-platinum and 30 (60 per cent) had an objective response to cis-platinum. An objective response (complete or partial remission) was noted in 43 patients (86 per cent) after cis-platinum plus definitive treatment. The 12-month actuarial survival was 86 per cent and the 2-year actuarial survival was 80 per cent (although only 14 patients were entered in the study more than 2 years ago). The protocol was well tolerated, with nausea and vomiting being the most common side effects. There were no deaths related to treatment. Ten patients (20 per cent) died of cancer. The relevance of initial cis-platinum therapy in this management program is now being evaluated in a multicenter randomized trial.

Adult↗
PubMed1985

Second malignant neoplasms in children: an update from the Late Effects Study Group.

This paper presents an update from the Late Effects Study Group on 292 cases of second malignant neoplasms (SMN) occurring in individuals who were diagnosed with their first neoplasm in childhood. Data are presented regarding the types of first and second neoplasm, the therapy administered, and the predisposing factors. Of the 292 cases (308 SMN), the most common primary was retinoblastoma followed by Hodgkin's disease, soft-tissue sarcomas, and Wilms' tumor. This is not similar to the relative frequency of these cancers in children but rather reflects specific risk factors. Bone sarcomas were the most common SMN among the 208 SMN developing in previously irradiated sites while acute leukemia was the most common SMN unassociated with radiation. Known predisposing conditions to cancer were present in 73 cases; retinoblastoma was the most common of these, followed by neurofibromatosis. There were ten patients with three and three patients with four malignant neoplasms. In 14 patients, the cause of SMN was not suggested by known risk factors as these patients had negative family histories and received no radiation or chemotherapy. We note, therefore, that although most cases of SMN in survivors of childhood cancer can be attributed to radiation, genetic disease, chemotherapy, or combinations of these, unrecognized predisposition or chance may also play a role.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1985

Clinical and laboratory investigation of the effects of epsilon-aminocaproic acid on hemostasis.

We previously reported that epsilon-aminocaproic acid (EACA) prolonged the bleeding time in patients with intracranial aneurysms when given in doses of 36 to 48 gm/day. We now show that doses of 24 gm/day also prolong the bleeding time, but only after 72 hours of continuous infusion. The effect on the bleeding time correlates with the duration of EACA therapy but not with the plasma level of the drug. Bleeding times return toward normal within 72 hours of discontinuing EACA infusions. The factors responsible for the bleeding time prolongation were investigated. In vitro, EACA inhibited adenosine diphosphate- and collagen-induced platelet aggregation and the release of platelet adenosine triphosphate and serotonin. It also prevented the adenosine diphosphate-stimulated binding of fibrinogen to intact as well as to chymotrypsin-treated platelets. However, platelets obtained from patients who had received EACA showed little functional impairment. This observation indicates that the focus of EACA activity in vivo is probably not the platelet per se, but the platelet-vessel wall interaction or a vascular component alone. EACA did not enhance prostacyclin production or release from cultured bovine endothelial cells. The fact that the effects of the drug on the bleeding time were related to the duration of EACA therapy suggests that an accumulation of the drug on the vessel wall may be required before alterations in hemostasis are observed. EACA in a daily dose of 24 gm significantly impaired fibrinolysis, but supranormal levels of fibrinolytic activity were observed within 72 hours of stopping the drug.(ABSTRACT TRUNCATED AT 250 WORDS)

Aminocaproates↗
PubMed1985

Sequential clinical and immunologic abnormalities in hemophiliacs.

We examined 35 patients with hemophilia to determine if there was an association between impaired cell-mediated immunity and the amount of factor concentrate use. There was a significant negative relationship between the logarithm of the helper-suppressor ratio and the logarithm of concentrate use determined over the previous one year, five years, and total lifetime. Similarly, the presence of splenomegaly was significantly associated with the logarithm of concentrate use for each time interval. Hypergammaglobulinemia, anergy, and lymphadenopathy were present in a high proportion of patients. Repeated study of 30 of these patients at eight to 14 months showed no significant changes in their T-cell subsets. At follow-up, 16 patients had lymphadenopathy with or without splenomegaly and four had splenomegaly alone. No significant associations between concentrate use during the study period and changes in T-cell subsets or clinical condition were found.

Adolescent↗
PubMed1984

Effect of hypoglycemic stress on plasma and cerebrospinal fluid immunoreactive beta-endorphin in conscious sheep.

The effect of insulin-induced hypoglycemic stress on the concentrations of immunoreactive beta-endorphin (ir beta-EP) in plasma and cerebrospinal fluid (CSF) was examined in conscious non-pregnant ewes in which the cisterna magna and a jugular vein had been previously catheterized. In control experiments, no significant changes were observed in plasma cortisol or ir beta-EP and CSF ir beta-EP concentrations. During hypoglycemia induced by intravenous injection of 20 units of insulin, plasma cortisol concentrations rose significantly, reaching a peak 1.5 h after injection. The changes in plasma ir beta-EP concentration were significantly different between hypoglycemic and normoglycemic sheep (analysis of variance, P = 0.0089). Following insulin injection, mean plasma ir beta-EP rose by 100% within 0.75 h, continued to rise six-fold over initial concentrations by 2.25 h, and remained elevated for 3.75 h. The CSF ir beta-EP concentrations following insulin injection were not significantly different from those observed in controls. These results suggest that if beta-endorphin mediated hypoglycemic stress-induced analgesia, its actions may be peripheral, not central.

Animals↗
PubMed1984

The integration of chemotherapy into the management of locally advanced cervical cancer: a pilot study.

Chemotherapy has been traditionally reserved as a last-time treatment for cervical cancer patients and in this setting long-term remissions are unusual. Platinum-based combination chemotherapy has been associated with high tumor response rates in patients with advanced and metastatic cervical tumors and past experience encouraged evaluation of chemotherapy as a first-line treatment in patients with locally advanced tumors where there is a high likelihood of relapse with local treatment. Thirty patients were treated initially with three courses of cis-platinum, vinblastine, and bleomycin with an overall response rate of 67%, and then had either radiotherapy or surgical resection. The initial results have been encouraging and the integration of chemotherapy into the management of locally advanced cervical cancer warrants further investigation.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1984

Effect of unilateral nephrectomy on growth of the Wistar/Furth Wilms' tumor.

Compensatory renal growth, that is, renal growth following contralateral nephrectomy, is mediated by either the elaboration or the activation of a renotrophic growth factor. Since tumor growth may be modulated by various factors, we evaluated the effect of the renotrophic growth factor associated with compensatory renal growth on the Wistar/Furth rat Wilms' tumor. When compared to tumors grown in sham nephrectomized animals, tumors grown in animals who had undergone unilateral nephrectomy showed an increase in tumor weight and in DNA content. In addition, the rate of new cell formation as reflected by the uptake of tritiated thymidine into tumor cells was significantly higher and did not decline when tumors grown in animals who had undergone unilateral nephrectomy were compared to tumors from sham nephrectomized animals. Our studies therefore suggest that the renotrophic growth factor associated with compensatory renal growth may have ubiquitous growth regulating activity and that further studies may elucidate its role in the modulation of normal and neoplastic growth.

Animals↗
PubMed1984

Kinetics of epsilon-aminocaproic acid distribution, elimination, and antifibrinolytic effects in normal subjects.

The kinetics of epsilon-aminocaproic acid (EACA) distribution and elimination were studied in six normal subjects after a single 10-gm iv dose. Steady-state distribution volume averaged 30.01 or 0.39 l/kg. Mean elimination t 1/2 was 294 min and the elimination clearance was 0.19 l/min. Renal excretion of unchanged EACA accounted for 68% of its elimination and renal EACA clearance averaged 115% of creatinine clearance. EACA antifibrinolytic effect kinetics were also characterized in five of the subjects by the monitoring of clot lysis times in whole blood and platelet-rich plasma. Peak antifibrinolytic effects were observed 15 to 60 min after peak EACA plasma concentrations were attained. A model of maximal fibrinolysis inhibition (Emax) was used to estimate a half-maximal inhibition (IC50) of 63 +/- 19.7 microgram/ml. This agrees with the value of 0.55 mM or 72 microgram/ml that has been reported for the dissociation constant of the EACA-plasminogen complex and is consistent with the proposed biochemical mechanism of EACA action.

Adult↗