72. Trachearesektionen und bronchoplastische Eingriffe bei Narbenstenosen,benignen und malignen Tumoren

Zusammenfassung In der Behandlung stenosierender Atemwegserkrankungen ist die Resektion mit End-zu-End-Anastomose die Therapie der Wahl. Resektionsstrecken bis zu 70% der Trachea, d. h. 7–8cm, sind möglich geworden, da durch neue Mobilisationsmanöver die Spannung an der Anastomose erheblich reduziert werden kann. An den Bronchien kann durch Teilresektion des tumortragenden Abschnittes das Ausmaß des Lungenparenchymverlustes vermindert werden, so daß auch Patienten mit eingeschränkter Lungenfunktion operabel werden.     

Transforming growth factor-beta trans-modulates the expression of colony stimulating factor receptors on murine hematopoietic progenitor cell lines

Transforming growth factor beta (TGF-beta) is a potent and selective growth inhibitor of early hematopoietic progenitors and leukemic cells. The cellular mechanism(s) underlying this antiproliferative effect is, however, currently unknown. In the present study, we demonstrate that TGF-beta inhibits the expression of granulocyte-macrophage colony stimulating factor (GM-CSF), interleukin 3 (IL-3), and granulocyte-CSF (G-CSF) receptors on murine factor-dependent and independent hematopoietic progenitor cell lines without a significant change in receptor affinity. A maximum reduction in GM-CSF receptor numbers of 65% to 77% was observed by 96-hour incubation with TGF-beta. The TGF- beta induced trans-down-modulation of GM-CSF receptors was prolonged, noncytotoxic but reversible, and not due to endogenous production of GM- CSF. The TGF-beta induced reduction in CSF receptor numbers preceded TGF-beta's growth inhibitory action. In addition, the ED50 (1 to 10 pmol/L) for TGF-beta's CSF receptor modulatory and antiproliferative effect was similar. The effect of TGF-beta on cell surface CSF receptor expression was specific, because the expression of other cell surface proteins (Ly 5 and Ly 17) was not affected by TGF-beta treatment, and because other growth inhibitors (tumor necrosis factor and interferon) did not affect CSF receptor expression. These data suggest that the downregulation of the growth of hematopoietic progenitor cells by TGF- beta involves reducing the cell surface expression on growth factor receptors.     

Factors that affect human hemopoiesis are produced by T-cell growth factor dependent and independent cultured T-cell leukemia-lymphoma cells

Some laboratory results and clinical situations suggest that human T cells may be important in the regulation of growth of hematopoietic cells. Since the discovery of T-cell growth factor (TCGF), systems are now available for the long-term specific in vitro propagation of mature normal or neoplastic human T cells, providing an opportunity to study the influence of T cells on hematopoiesis. Recently, 24 cell lines from patients with cutaneous T-cell lymphoma (CTCL) and T-cell acute lymphoblastic leukemia (T-ALL) were grown with TCGF and then assessed for release of humoral factors that affect hematopoiesis. Conditioned media (CM) from these cell lines were tested for erythroid burst- promoting activity (BPA) and granulocyte colony-stimulating activity (CSA). BPA was detected in CM from 3/6 cultures of T-ALL patients and 4/6 CTCL cultures. CSA was found in the CM from 6/8 cultures of T-ALL patients, 7/12 CTCL cultures, and 3/4 CTCL cell lines that become independent of exogenous TCGF for growth. The CSA from several of the neoplastic T-cell cultures stimulated high levels of eosinophil colonies, a possible source of the eosinophilia seen in these patients. The ability of continuously proliferating human T lymphocytes, which retain functional specificity and responsiveness to normal humoral regulation, to produce factors that directly or indirectly stimulate myeloid and erythroid colony formation lends further credence to the role of T lymphocytes in regulating hematopoiesis.     

Evaluation of erythropoiesis in long-term hamster bone marrow suspension cultures: absence of a requirement for adherent monolayer cells

In long-term hamster bone marrow cultures, proliferation and differentiation of hemopoietic stem cells occurs for several months without need for hydrocortisone or adherent stromal elements, which are requirements for bone marrow growth in all other species studied. Only the most primitive erythroid progenitors (BFU-E) are produced in the cultures. Following treatment of the cells with erythropoietin, these progenitor cells undergo differentiation into mature hemoglobinized red blood cells. Concomitant addition of erythropoietin (Epo) and prostaglandin-E1 (PGE1) results in the production of large numbers of maturing red blood cells. In cultures stimulated with Epo and PGE1, as many as 70% of the cells are benzidine-positive, while Epo alone stimulated as many as 45% of the cells to become erythroid. Epo and PGE1 do not have any apparent deleterious effect on the continuous hemopoiesis occurring in these cultures. Under identical conditions, syngeneic adherent cell cultures do not produce any erythroid elements. The development of mature red blood cells from primitive erythroid precursors occurs in the presence of Epo alone and without any apparent need for adherent stromal elements. These cultures provide a useful in vitro model for dissecting the positive and negative signals that regulate erythropoiesis.     

Invasion of erythrocytes by Plasmodium falciparum malaria parasites: evidence for receptor heterogeneity and two receptors

Plasmodium falciparum malaria parasites with different capabilities of invading sialic acid-deficient erythrocytes were identified. Thai-2 parasites cultured in Tn erythrocytes invaded neuraminidase-treated and Tn erythrocytes twice as efficiently as Thai-2 parasites cultured in normal erythrocytes and seven to ten times more efficiently than a cloned line of Camp parasites cultured in normal erythrocytes. All three parasite lines required sialic acid for optimal invasion, but Thai-2 parasites cultured in Tn erythrocytes invaded neuraminidase- treated erythrocytes with 45% efficiency whereas Camp parasites invaded neuraminidase-treated erythrocytes with less than 10% efficiency. P falciparum malaria parasites probably possess two receptors: one that binds to a sialic acid-dependent ligand and another that binds to a sialic acid-independent ligand. Parasites may differ in the quantity or affinity of their receptors for the sialic acid-independent ligand.     

The acute phase response following implantation of triclosan-bonded vascular prostheses

Objective. Infection of prosthetic material is a major complication of vascular surgery. Therapy for it includes implantation of antimicrobial prostheses bonded with different antimicrobial agents. These agents may, however, induce an acute phase reaction following implantation in the host, thus compromising follow-up of the infection. It is not known whether the antimicrobial agent triclosan induces a significant acute phase reaction when bonded to vascular prostheses. Methods. To study this, 34 adult swine weighing 20–30 kg were allotted randomly to the following groups: (1) controls with untreated prostheses, (2) control group with triclosan-bonded prostheses, (3) therapy group with untreated prostheses, local infection with Staphylococcus aureus, surgical revision, and exchange with new, untreated prostheses, and (4) therapy group with untreated prostheses, local infection with S. aureus, surgical revision, and exchange with triclosan-bonded prostheses. Serum C-reactive protein (CRP) and haptoglobin values were determined during the 28-day period after surgery. The study was performed at the Institute for Surgical Research of the Ludwig Maximilian University School of Medicine in Munich. Results. Normal ranges of serum CRP and haptoglobin values were 10.7±1.4 μg/ml and 2.5±0.3 mg/ml, respectively. Following implantation of untreated and triclosan-bonded vascular prostheses, significantly elevated serum CRP and haptoglobin values were observed. No significant differences between results with triclosan-bonded and untreated prostheses were observed in control or treatment groups. No correlation was found between acute phase reaction and the absence or presence of infection. Conclusions. Triclosan is the only antimicrobial agent that bonds to vascular prosthetic material without the need of a sealant. Our data indicate that vascular prosthesis implantation, whether untreated and triclosan-bonded, results in a sigificant acute phase reaction. No differences between antimicrobial and untreated prostheses were observed, independently of the absence or presence of infection. The antimicrobial agent itself did not induce a severe acute phase response and may, therefore, be used in patients at risk of infection. Received: 16 August 2000 / Accepted: 17 November 2000     

Transabdominal preperitoneal hernia repair (TAPP). Results of 1,000 completed operations]

It was the aim of this report to evaluate the laparoscopic transabdominal preperitoneal hernia repair (TAPP) which has been standardized at our department. Along with the demographic characterisation of 795 patients with 1000 inguinal hernia repairs we report about complications and early recurrences. The patient data were collected prospectively. The rate of follow-up amounted to 79.9% with an average follow-up of 1 year. The complications were divided into intraoperative, minor, major, as well as severe ones. In 30 repairs minor complications (3%) were detected. Major (n = 28) and severe (n = 9) complications were detected in 3.7% of the cases. There were two deaths, 3 patients with an intestinal obstruction due to adhesions (2 segmental small bowel resections), two patients with testicular atrophy, two mesh infections, two trocar hernias, 6 surgical revisions for removal of hematomas, one exploration of a testicle, 4 diagnostic laparoscopies for suspected recurrences with a negative result, and 15 patients with a nerve irritation syndrome. The early rate of recurrence was 0.7%. In 6 cases primary hernias had been repaired and in one case a recurrent hernia. The recurrent hernias became apparent in an average of 2 years (minimum 2.5 months, maximum 36 months) after surgery. The results of the clinical study demonstrate an acceptable rate of complications and a low rate of early recurrences. Based on these data we recommend the laparoscopic transabdominal preperitoneal technique and see an ideal indication in the case of bilateral, recurrent and femoral hernias.     

人工神经元网络用于复方氯丙嗪的含量测定

将误差反向传播(BP)的人工神经元网络(ANN)模型，用于复方氯丙嗪紫外重叠光谱分 析。对ANN模型的参数进行了优化。采用f(x)二1/(1+e^-x)作为网络节点的输入输出转换函数的三 层神经网络具有较佳性能，当取隐含节点数为15时，该网络预测结果的最小平均相对误差为1.22％， 将研制的ANN模型用于复方氯丙嗪含量测定，其结果与药品标准法和偏最小二乘法(PLs)一致。