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S Runkel

Publications and source records attributed to S Runkel.

27 records · Page 2Linked to original sources
PubMed1988

Glucose uptake, lactate release, ketone body turnover, metabolic micromilieu, and pH distributions in human breast cancer xenografts in nude rats.

Glucose uptake, lactate release, ketone body utilization, spatial distribution of glucose, lactate, and ATP concentrations as well as tissue pH distributions were systematically investigated in s.c. and/or "tissue-isolated" human breast cancer xenografts in T-cell-deficient rnu/rnu rats. Large variations in all parameters were detected within and between tumors indicating a very nonuniform substrate turnover. Glucose was taken up by all xenografts. Glucose consumption rates increased with increasing glucose availabilities, implying that the glucose uptake is mainly determined by the efficiency of nutritive tumor blood flow. The average glucose uptake was 0.37 mumol/g/min in medullary and 0.26 mumol/g/min in squamous cell carcinomas of the breast. At wet weights below 5 g, medullary breast cancers consumed more glucose than squamous cell carcinomas (2P less than 0.05). Most tumors (97%) released lactate in an amount linearly related to glucose consumption. The lactate production of medullary (0.33 mumol/g/min) and squamous cell (0.31 mumol/g/min) breast cancers was similar. In general, the xenografts utilized ketone bodies. beta-Hydroxybutyrate was consumed by 82% and acetoacetate by 73% of the tumors, the uptake rates being linearly related to the respective availabilities. The mean uptake of beta-hydroxybutyrate was 3.48 nmol/g/min and that of acetoacetate 2.56 nmol/g/min. No significant differences were seen between medullary and squamous cell breast cancers. The beta-hydroxybutyrate/acetoacetate ratio in the tumor-venous blood rose with decreasing tumor blood flow indicating the development of hypoxia at advanced growth stages. Glucose, lactate, and ATP levels were all very heterogeneously distributed in medullary and squamous cell tumors as compared with normal tissue. No relationship was evident between the spatial distribution of concentrations of these three substrates. The xenografts were acidotic compared with pH values in normal subcutis. The mean tissue pH in medullary breast cancers was 6.81 +/- 0.25 (SD). Compared with these values, the tissue pH distribution in squamous cell breast cancers was shifted to significantly higher values. The mean pH of the latter tumors was 7.04 +/- 0.19 (2P less than 0.001). From the experimental data presented there is clear indication that the metabolism of the xenografts investigated was mainly determined by the efficiency of nutritive blood flow, i.e., by substrate availability, and not by the metabolic demand of the cancer cells.

Animals↗
PubMed1987

Blood flow, oxygen consumption, and tissue oxygenation of human breast cancer xenografts in nude rats.

Human breast cancer xenografts in T-cell-deficient rnu/rnu rats permit the detailed and systematic study of blood flow, oxygen supply, and characterization of the cellular microenvironment of human tumors in vivo. Using an epigastric pouching technique, it is possible to obtain a tissue-isolated preparation which makes direct studies of blood flow and oxygen supply in human tumors feasible. So far, medullary and squamous cell carcinomas of the breast from patients have been investigated under well-defined systemic conditions. At comparable tumor sizes, the average blood flow rate through human breast cancer xenografts is higher in medullary than in squamous cell carcinomas (0.17 versus 0.10 ml X g-1 X min-1). Blood flow per unit tumor mass significantly decreases with increasing wet weight. No significant differences are obvious when comparing the flow values of pre- and postmenopausal tumors or of cancer tissues with different hormone receptor capacities. On the average, the oxygen consumption rates of human breast cancer xenografts are 10.4 in medullary and 7.7 microliter O2 X g-1 X min-1 in squamous cell carcinomas. With increasing tumor mass, the O2 consumption rate per unit weight significantly decreases. This decrease parallels the respective decline of tumor blood flow, implying that the O2 consumption rate of the cancer cells in vivo is mostly limited by the nutritive blood flow, i.e., by the O2 availability to the tumors. Due to a restricted blood supply, the O2 utilization of human breast cancer xenografts is high. Tissue oxygenation in microareas of human breast cancers xenotransplanted s.c. into nude rats is mostly inadequate. As a consequence, tissue hypoxia and anoxia are common findings even in very early growth stages. Due to marked intra- and intertumor variabilities in blood flow, heterogeneities in the tissue oxygenation are characteristic features of human breast cancer xenografts. From the results obtained it is concluded that human breast cancers growing as xenografts in rnu/rnu rats may be useful tools for cancer research, especially for investigations of blood flow, tissue oxygenation, and substrate turnover.

Animals↗
PubMed1987

L-glutamine: a major substrate for tumor cells in vivo?

From 65 human breast cancer xenografts investigated, a net glutamine uptake was found in 13 tumors (mean +/- SE: 15.7 +/- 4.5 nmol/g per min) whereas a net release (22.5 +/- 3.3 nmol/g per min) was observed in 40 tumors. In 12 tumors neither a significant net uptake nor a net release was obvious. There is experimental evidence that glutamine is taken up by cancer cells only at arterial concentrations greater than 0.5 mM. Another parameter determining glutamine utilization by tumor cells may be the tissue oxygenation. In hypoxic or anoxic tumor areas, glutamine oxidation is unlikely since oxygen is required for the reoxidation of coenzymes which are reduced in the course of this metabolic pathway. The pronounced net release could be due to proteolysis within the tumors investigated. In ascitic fluid (DS-carcinosarcoma), glutamine accumulated during growth, implicating a reduction in the glutamine consumption rate, proposedly also due to a worsening of the oxygen supply to the suspended tumor cells. Thus, the generally held opinion that L-glutamine is a (if not the) major substrate for the energy metabolism of rapidly growing tumor cells should be reconsidered since evidence for this hypothesis has been derived mainly from in vitro systems with abundant oxygen.

Animals↗
PubMedDate not supplied

Feto-feto-fetal triplet transfusion syndrome (FFFTTS).

We report a case of feto-feto-fetal-transfusion-syndrome (FFFTS) in a spontaneous monochorionic triamniotic triplet pregnancy primarily diagnosed at 17 weeks of gestation. During the course of pregnancy, sequentially two triplets appeared as donor. Symptoms of a recipient (polyhydramnios, tricuspid valve insufficiency, and ascites) were present in the third triplet. The second of the donor twins died in utero at 25 weeks. At 27 weeks, a cesarean section was performed mainly due to pre-eclampsia. The first donor triplet developed normally, whereas the recipient showed periventricular leucomalacia and neurological impairment.

Cesarean Section↗
PubMedDate not supplied

Prenatal diagnosis of a lethal multiple pterygium syndrome type II. Case report.

Advances in ultrasound technology and sonographer's experience lead to the description of many rare syndromes and malformations through prenatal diagnosis. Diaphragmatic hernia is a rather common malformation but can be an indicator of different syndromes. We report the prenatal diagnosis of lethal multiple pterygium syndrome type II which has been established in the 34th week of pregnancy. The sonographically detectable symptoms consisted of polyhydramnios, hygroma colli, diaphragmatic hernia, scoliosis, short forearms, hypokinesia of the fetus and pterygia over the large joints. Labour was induced in the 34th week of pregnancy; the neonate died shortly after vaginal delivery as a result of the pulmonary hypoplasia. A multidisciplinary approach in prenatal assessment may help to clarify difficult diagnostic problems and may be of direct benefit for the pregnant patient.

Abnormalities, Multiple↗
PubMedDate not supplied

Prenatal diagnosis of body stalk anomaly at 9 weeks of gestation. Case report.

We report on a case of embryonic anomaly detected at 9 + 5 gestational weeks. The lower part of the embryo was located in the coelomic cavity. Lower extremities could not be depicted. The abdominal wall showed the appearance of omphalocoele. After termination of pregnancy at 10 weeks, autopsy confirmed the anomaly of the lower embryonic parts consistent with the diagnosis of body stalk anomaly. To our knowledge, this is the first observation of this condition before 10 gestational weeks.

Abortion, Eugenic↗