Long-Term Continuous Cultivation of Clostridium beijerinckii in a Two-Stage Chemostat with On-Line Solvent Removal

A two-stage continuous cultivation experiment with Clostridium beijerinckii NRRL B592 is described. This strain maintained its ability to produce neutral solvents (acetone, n-butanol, and ethanol) at an overall dilution rate of 0.13 h(sup-1) and achieved an average overall solvent concentration of 9.27 g/liter and an overall solvent productivity of 1.24 g/liter/h for more than 100 overall retention times. The experiment was performed without pH control on a semisynthetic medium containing yeast extract, and product inhibition was the limiting factor. Solid carrier material was present in both stages, and the solvent productivity in both stages was similar. A membrane evaporation module integrated into the recirculation loop of a second-stage bioreactor after 2,166 h increased solvent productivity and improved the yield of solvents by about 40%. The membrane reduced the concentration of solvents, which would otherwise inhibit the fermentation. Additionally, the integrated membrane evaporation dampened metabolic oscillations, which are characteristic of continuous cultivation of clostridia. It was also demonstrated that a moderate concentration buildup (approximately 30% of bioreactor inflow) caused by water flux through the membrane caused no detrimental effects to the bacterial cells. However, much higher water fluxes through the membrane, associated with a much more dramatic increase in the concentration of salts in the medium, did appear to favor cell degeneration.

Radiofrequency catheter ablation of a concealed accessory atrioventricular pathway after heart transplantation

Three months after orthotopic cardiac transplantation, a 46-year-old man developed paroxysmal supraventricular tachycardia. Electrophysiological investigation of the arrhythmia led to the diagnosis of an atrioventricular reentrant tachycardia involving a left lateral concealed accessory pathway. When antiarrhythmic drugs failed to suppress the arrhythmia, radiofrequency catheter ablation of the accessory pathway was performed without complication.

Altered expression of titin and contractile proteins in failing human myocardium

Our own previous ultrastructural studies in human hearts with dilated cardiomyopathy and heart failure showed sarcomeric and cytoskeletal disarrangement. On the basis of these findings we tested the hypothesis that in cardiomyopathic failing hearts not only the sarcomere structure but also the organization and the amount of numerous contractile proteins are disturbed. Titin was included in this study because it is the elastic "third" filament of the sarcomere and also plays an important role as template for myosin and actin filaments in sarcomerogenesis. Human cardiac tissue obtained at the time of transplantation surgery was investigated using immunohistochemistry with monoclonal antibodies against titin, myosin, actin, tropomyosin, and troponin T. Additionally, isolated myocytes from rat or pig heart were used for the standardization of the localization pattern. In normal tissue, myosin and the thin filament complex showed a regular cross striation that was wider in myosin staining than for actin, troponin T, and tropomyosin corresponding with the different width of the A and I bands in the sarcomere. Titin localization in normal human and animal myocardium showed a regular cross striation pattern. In diseased cardiac tissue titin fluorescence intensity was reduced and frequently disorganization or almost complete loss of titin from many myocytes were present. Severe abnormalities of contractile proteins consisting of disarrangement or lack of filaments were also observed. Double staining procedures showed that in the same myocyte defects of the contractile apparatus were accompanied by a simultaneous reduction of titin indicating that the "third" sarcomeric filament system is involved in heart failure. Abnormalities of titin expression may be especially important because titin significantly influences sarcomeric elastic behaviour and is necessary as template for the organization of newly synthesized myosin and actin filaments. The loss of titin may contribute to the altered compliance in failing hearts. It is concluded that disorganization and loss of titin, myosin, and the thin filament complex are severe in the failing human heart because of dilated cardiomyopathy and that these changes may represent several of the most important components of the structural correlate of reduced cardiac function.

[Doppler and echocardiography parameters in detection of acute graft rejection after heart transplantation]

Due to the invasive nature of myocardial biopsies, a complication rate of up to 2.5%, and the limitations, e.g., at focal distribution of rejection, there is a continuous need for reliable, non-invasive parameters in recognizing moderate (grade 2) and severe (grade 3) acute cardiac allograft rejections in patients treated with cyclosporine A. 64 biopsies of 20 patients with previous heart transplantations in the past 3 weeks to 36 months (mean 11 months) were compared prospectively to Doppler and echocardiographic results. Parameters of systolic function such as percent fractional shortening (FS) and systolic wall thickness of the posterior wall (SWT) remained without significant changes at grade 2 and grade 3 rejections. The same is valid for relaxation parameters such as maximum velocity of posterior wall reduction (PTR), the time interval of endsystole to maximum velocity of posterior wall reduction (tES-PTR), and the isovolumic relaxation time (IVRT). Left-ventricular filling parameters such as maximum early diastolic flow velocity (VEmax) increased significantly from 73.3 +/- 15.2 cm/s in the rejection-free interval (grade 0) to 103.9 +/- 15.0 cm/s at grade 2 rejection and 101.1 +/- 9.2 cm/s at grade 3 rejection (both p < 0.001). A sensitivity of 50% and a negative predictive value of 77% are, however, too low to diagnose or exclude a moderate or severe acute rejection in the individual case.(ABSTRACT TRUNCATED AT 250 WORDS)

Oestradiol stimulates growth of oestrogen receptor-negative MDA-MB-231 breast cancer cells in immunodeficient mice by reducing cell loss

Growth stimulation by oestrogens in immunodeficient mice is characteristically restricted to tumours expressing oestrogen receptors (ER). We now describe oestrogen-stimulated growth of the ER-negative human breast cancer cell line MDA-MB-231, subclone 10A. Cell culture experiments confirmed that 10A cells are unresponsive to a wide concentration range of oestradiol (E2) in vitro. Analysis of growth curves in vivo revealed significantly longer tumour volume doubling times for the control group than for the E2-treated group. Cell cycle studies using in vivo labelling with bromodeoxyuridine (BrdU) and flow cytometric analysis showed essentially equal potential doubling times for controls and E2-treated animals. These results suggest that E2 reduces cell loss, rather than stimulating proliferation. E2-stimulated growth was seen in both natural killer (NK) cell producing athymic (nude) mice and congenitally NK cell deficient beige nude mice. We conclude that E2-induced natural killer cell suppression is an unlikely mechanism of action.

What do we know and what don't we know about tamoxifen in the human uterus

Since its introduction in the early seventies, the list of indications for the use of the antiestrogen tamoxifen has been continuously expanded. Tamoxifen is now used for the treatment of metastatic breast cancer and for long-term and often indefinite administration as an adjuvant therapy. Large clinical trials in three countries are now evaluating the efficacy of tamoxifen as a preventive agent. However, tamoxifen therapy has been associated with an increased incidence of endometrial carcinoma. Laboratory and clinical data available to date on this controversial issue can be summarized as follows: a) Tamoxifen can have an estrogenic effect on endometrium in the presence of low estrogen levels. b) Tamoxifen treatment is probably associated with an increased incidence of endometrial cancer; however, this association appears to be linked to higher tamoxifen doses (40 mg/d). d) It is not known whether tamoxifen causes or allows the identification of occult endometrial carcinoma. e) At the present time there is evidence for a tumor promoting effect of tamoxifen on endometrial cancer at a dose of 20 mg per day. f) Replacement of tamoxifen by 'pure' antiestrogens or coadministration of progestins with tamoxifen do not appear to offer benefit unless clinical trials demonstrate a reduced incidence of endometrial problems. g) Patients must be evaluated for pre-existing endometrical carcinoma before starting tamoxifen therapy. f) Close followup of long-term tamoxifen patients with endometrial biopsies is recommended with individuals who experience symptoms.

[Cardioverter-defibrillator implantations without thoracotomy: clinical experience with various electrode configurations and defibrillation wave forms of an endocardial/subcutaneous defibrillator system]

Twenty-seven consecutive patients with refractory ventricular arrhythmias were investigated for implantation of an nonthoracotomy cardioverter-defibrillator lead system. Supply with a nonthoracotomy lead system could be achieved in 25 of 27 patients (92.5%), while implantation proved impossible in two patients due to elevated defibrillation thresholds. After implantation of an endocardial defibrillation electrode no differences were found compared to the implantation of an endocardial defibrillation electrode with a subcutaneous chest wall defibrillation patch with regard to the defibrillation thresholds obtained for monophasic defibrillation waveform. Supply with an endocardial defibrillation lead system was successful in 18 of 25 patients (72%). Ten consecutive patients with implantation of an endocardial defibrillation lead system alone were compared for defibrillation efficacy following monophasic and biphasic defibrillation waveforms. Defibrillation with biphasic waveforms led to a decrease in the necessary defibrillation energy from 19 J (4.6 J) to 10 J (4.0 J). There was occurrence of refractory ventricular fibrillation that could not be controlled by endocardial and transthoracic defibrillation in two patients during the intraoperative testing of defibrillation thresholds. In both cases these arrhythmias could be terminated by the described method of endocardial/extrathoracic defibrillation (200 J). Further perioperative complications were not observed. Over a mean follow-up of 6.8 (1-17) months all patients demonstrated regular functioning of the cardioverter-defibrillator. Dislocation of defibrillation electrodes did not occur. Implantation of a cardioverter-defibrillator can be performed without thoracotomy in the majority of cases. The use of defibrillator systems with biphasic waveform widens the scope for implantation of nonthoracotomy defibrillating lead systems.

Suppression of serum insulin-like growth factor-1 levels in breast cancer patients during adjuvant tamoxifen therapy

Serial IGF-1 levels in patients prior to and during adjuvant tamoxifen (TAM) treatment were followed in a retrospective study. Serum IGF-1 levels were determined by radioimmunoassay in 19 patients taking TAM and 19 controls, matched for age, body weight and other treatments. IGF-1 levels at 2 years were significantly lower in TAM patients (P < or = 0.05) compared to control patients. We observed a significant mean drop from pretreatment to treatment IGF-1 levels by 19.9% in the TAM group (P < or = 0.005), but also noted a mean 11.4% decline in the control group (P < or = 0.025). A subgroup analysis suggested that premenopausal were relatively resistant to the IGF-1 lowering effects of TAM as compared to postmenopausal women.

Characterization of specific binding sites for [3H]-1,3-di-o-tolyl-guanidine (DTG) in the rat glioma cell line C6-BU-1

The aim of the present study was to find out if a cell line of glial origin possesses sigma and/or phencyclidine (PCP) binding sites. Binding of [3H]1,3-di-o-tolyl-guanidine (DTG), a highly selective ligand for sigma binding sites, and of [3H]N-[1-(2-thienyl)cyclohexyl] piperidine ([3H]TCP), a radioligand specific for PCP receptors, to C6-BU-1 glioma cells was investigated. Binding of [3H]DTG to C6-BU-1 cell membranes was reversible, saturable (Bmax = 10.5 pmol/mg protein), and of high affinity (KD = 26 nM). C6-BU-1 cells do not possess PCP receptors as indicated by negligible specific binding of [3H]TCP to C6-BU-1 cell membranes. Specific binding of [3H]DTG was reduced in the presence of Ca2+ and to a lesser extent by Mg2+. The rank order of potency of various PCP and sigma ligands was DTG > (+)3-[(3-hydroxy-phenyl)-N-n-propyl-piperidine] [(+)3-PPP] > haloperidol > pentazocine > (-)3-PPP > PCP > metaphit > dextromethorphan > (-)butaclamol > (+)butaclamol > (-)N-allylnormetazocine [(-)SKF 10,047] > MK801 > (+)SKF 10,047 > ketamine. The drug specificity, confirmed by a reversed stereoselectivity for the benzomorphan opiate SKF 10,047, indicated that these sites correspond to a subtype of sigma binding sites, the so-called sigma 2 binding site. Thus, the C6-BU-1 cell line is the first glial cell line demonstrated to have sigma 2 binding sites.

Identification and characterization of two sigma-like binding sites in the mouse neuroblastoma x rat glioma hybrid cell line NG108-15

NG108-15 cells were shown to possess high affinity binding sites for 1,3-di(2-[5-3H]tolyl)guanidine ([3H]DTG), a selective sigma ligand (Kd = 23 nM; maximal number of binding sites = 15.6 pmol/mg). The rank order of potency of drugs at this site was DTG greater than haloperidol greater than pentazocine greater than 3-(3-hydroxyphenyl)-N-(1-propyl)piperidine [(+)-3-PPP] greater than phencyclidine (PCP) greater than metaphit greater than (-)-3-PPP greater than (-)-N-allylnormetazocine [(-)-SKF 10,047] greater than (-)-butaclamol greater than (+)-butaclamol greater than (+)-SKF 10,047 greater than dizolcipine (MK 801 [5-methyl-10,11-dihydro-5H-dibenzo(a,d)cyclohepten-5,10-imine- maleate]) greater than ketamine. Both, Kd value and pattern of ligand selectivity suggest a close relationship to sigma sites in rodent brain. However, in comparison to sigma sites in brain stereoselectivity for the benzomorphan, SKF 10,047 was reversed and the affinities for benzomorphans were only moderate to low. Thus, sigma binding sites in NG108-15 cells seem to correspond to recently detected sigma sites in a pheochromocytoma cell line (PC12). [3H]-1-(2-thienyl)-cyclohexyl]piperidine ([3H]TCP), a PCP receptor-selective ligand binds to NG108-15 cells with moderate affinity (Kd = 139 nM; maximal number of binding sites = 4.7 pmol/mg of protein).(ABSTRACT TRUNCATED AT 250 WORDS)

Impairment of the myocardial ultrastructure and changes of the cytoskeleton in dilated cardiomyopathy

This study was designed to determine the morphological correlate of chronic heart failure. Myocardial tissue from eight patients undergoing transplantation surgery because of end-stage dilated cardiomyopathy was investigated by electron microscopy and immunocytochemistry using monoclonal antibodies against elements of the cytoskeleton: desmin, tubulin, vinculin, and vimentin. The tissue showed hypertrophy, atrophy of myocytes, and an increased amount of fibrosis. Ultrastructural changes consisted of enlargement and varying shape of nuclei, numerous very small mitochondria, proliferation of T tubules, and accumulation of lipid droplets and glycogen. The most obvious ultrastructural alteration was the decrease of myofilaments, ranging from rarefication to complete absence of sarcomeres in cells filled with unspecified cytoplasm. Immunocytochemistry showed that desmin was localized at the Z lines. In diseased myocardium, the amount of desmin was increased, but it was disorderly arranged. Tubulin formed a fine network throughout the myocytes and was significantly increased in cardiomyopathic hearts. Vinculin, a protein closely associated with the cytoskeleton, occurred not only at the sarcolemma and the intercalated disc but also within the myocardial cells. Ultrastructural changes and alterations of the cytoskeleton were severe in about one third of all cells. About one third of all cells showed moderately severe changes, and the remaining cells were normal. Vimentin was present in the interstitial cells and was increased in relation to the increase of fibrosis. We conclude that the increase of fibrosis, the degeneration of hypertrophied myocardial cells, and the alterations of the cytoskeleton are the morphological correlates of reduced myocardial function in chronic heart failure.

Enhanced growth of an estrogen receptor-negative endometrial adenocarcinoma by estradiol in athymic mice

The aim of this study was to investigate the effects of estradiol and tamoxifen (TAM) on the growth of human endometrial carcinomas in athymic mice. Tissues from primary tumors were implanted into estradiol-treated mice. In passage 2, animals were treated with (a) placebo, (b) estradiol, (c) estradiol plus TAM, and (d) TAM alone. The size of the tumors was measured weekly. Estrogen receptors (ER) were determined with the dextran-coated charcoal method and/or ER enzyme-linked immunoassay. Progesterone receptors were measured with the dextran-coated charcoal technique. Of 16 primary tumors, 2 grew in the athymic mice and were studied further. Tumor EL was positive for ER (145 fmol/mg protein) and progesterone receptors (993 fmol/mg protein). Tumor EL in passage 2 was not significantly stimulated by estradiol, but was stimulated by a combination of estradiol and TAM. Treatments (estradiol, estradiol plus TAM, or TAM) all increased tumor growth in passage 3. Tumor BR and a metastasis BR-MET were ER and progesterone receptor negative, applying dextran-coated charcoal, ER enzyme-linked immunoassay, and immunocytochemistry. The BR and BR-MET cells contain the complete ER gene but do not express any measurable amounts of ER mRNA as quantitated by Northern blot analysis, using a complete ER complementary DNA probe. In all animal passages the growth rate was significantly higher in estradiol-treated mice compared with the control. TAM alone had some growth stimulatory effect, but much smaller than observed in the estradiol group. TAM inhibited estradiol-stimulated growth. These results suggest that estradiol and possibly TAM are capable of stimulating tumor growth in the athymic mice independently from ER, potentially through a host-mediated mechanism.

Elevation by atrial natriuretic factors of cyclic GMP levels in astroglia-rich cultures from murine brain

Atrial natriuretic factors, peptide hormones originally found in the heart, slowly but strongly elevate the level of cyclic GMP in primary astrocyte-rich cultures derived from brains of newborn rats or mice but not in neuron-rich cultures prepared from embryonic rat brain. In the absence of a phosphodiesterase inhibitor, a plateau level of cyclic GMP is obtained within 10 min. In the presence of the inhibitor 3-isobutyl-1-methylxanthine, the concentration of cyclic GMP continues to rise, even after 30 min. The elevation of the level of cyclic GMP in response to atrial natriuretic factor is much more pronounced in the rat cultures than the mouse cultures. Even at peptide concentrations of 1 microM, plateaus of the concentration-response curves are not yet reached. The potencies of the active peptides vary over a range of approximately 1.5 orders of magnitude, with atriopeptins II and III and auriculin A being the most potent ones. These results suggest (a) that atrial natriuretic factors may regulate functions of glial cells, most likely of astrocytes, in brain and (b) that such cultures may be useful tools in defining such astroglial functions.

Immune-deficient animals to study "hormone-dependent" breast and endometrial cancer

Athymic (nu/nu) mice are T cell deficient and can accept xenografts of human tumor material. Hormone-dependent tumor growth can be demonstrated in ovariectomized athymic mice by estrogen administration. Estrogen receptor (ER) positive MCF-7 breast cancer cells implanted into the axillary mammary fat do not grow into palpable tumors unless sustained release preparations of estrogen are administered. The non-steroidal antiestrogen tamoxifen, though it exhibits estrogenic properties in the mouse, does not facilitate MCF-7 tumor growth (during short term, i.e. 8 weeks of therapy) and can prevent estradiol-stimulated growth. In contrast, ER negative MDA-MB-231 cells grow with or without estrogen administration and tamoxifen does not control tumor growth. These statements reflect current dogma concerning the value of athymic mice to confirm the hormone dependent growth of cancer cells in vivo. Our aim has been to define the limits of this dogma and to investigate the growth relationship of hormone-dependent and independent cells with their host environment. The potential endocrine or paracine effect of ER negative tumors on the growth of ER positive tumors was evaluated by transplantation on opposite sides of athymic mice or by the inoculation of different ratios of ER positive/negative cells (MCF-7:MDA-MB-231 9:1, 99:1, 999:1). MCF-7 cells could not be encouraged to grow by a rapidly growing MDA-MB-231 tumor on the opposite side of the animal. Similarly ER negative tumors grew out of the mixed tumor inoculates suggesting that ER positive tumors could not be encouraged to grow preferentially by the paracrine influences of ER negative cells. However, estrogen facilitates the growth of an ER positive tumor following inoculation of mixed cell populations. Antiestrogen treatment can blunt estrogen-stimulated growth but cannot control the growth of ER positive/negative containing tumors. ER positive endometrial tumors grow in response to estrogen treatment and some (EnCa101) have been shown to grow in response to tamoxifen or a combination of tamoxifen and estrogen. More unusual though is our recent observation that an ER negative primary endometrial tumor (BR) and its metastasis (BR-MET) grow more rapidly in estrogen-treated athymic mice. This finding seems to have far-ranging consequences for our view of hormone-dependent growth. Either our view of estrogen-stimulated growth needs to be modified or the host is specifically altered during estrogen treatment. We have taken the position that since natural killer cells (present in athymic mice) can be lowered by estrogen this may result in an increased tumor cell survival in the heterotransplant model.(ABSTRACT TRUNCATED AT 400 WORDS)

Heterotopic heart transplantation: current indications for the procedure, with results in 10 patients

From January 1986 to September 1987, we performed 27 orthotopic and 10 heterotopic cardiac transplantations at our institution. Of the 10 heterotopic transplantation recipients, 9 were men; ages ranged from 36 to 65 years; and indications for transplantation were ischemic cardiomyopathy in 8 patients and dilatative cardiomyopathy in 2 patients. Five of the 10 heterotopic transplantation recipients received donor hearts under emergency conditions, when no hearts of suitable size for orthotopic transplantation were available. In 3 of the 10 heterotopic procedures, we performed pure left ventricular (rather than biventricular) bypass in patients with chronic conditions requiring only aneurysmectomy, or aneurysmectomy in combination with an aortocoronary graft. During postoperative hospitalization, the following complications occurred in the 10 heterotopic-transplantation recipients: 10 infectious episodes in 6 patients; 1 episode of severe graft rejection; and 1 episode of severe gastrointestinal bleeding. All these complications were overcome, and no patient in the heterotopic-transplantation group died. Fifteen months postoperatively, one male in the group lost his graft, but his own heart had by then recovered function, despite dilatative cardiomyopathy. More commonly, late investigation (6 months or longer after transplantation) has yielded ambiguous overall evaluations of pump performance of the recipients' native hearts, showing slight improvement in some instances and further deterioration in others. We conclude that heterotopic heart transplantation is a life-saving procedure in urgent cases when only small donor hearts are available, and that it offers a good chance of hemodynamic and functional improvement not only in emergency cases, but also in cases of chronic cardiomyopathy when there is salvageable myocardium.

Atrial natriuretic hormones raise the level of cyclic GMP in neural cell lines

Atriopeptin III and related atrial natriuretic peptide hormones strongly elevate the level of cyclic GMP in three neural tumor cell lines. At peptide concentrations of 1 microM clear-cut plateaus of the dose-response curves are not yet reached. Atriopeptin III increases the intracellular concentration of cyclic GMP to a maximum in the course of 30-40 min. The effect of atriopeptin III on the cellular cyclic GMP level is independent of the concentration of extracellular Ca2+ and is not affected by the Ca2+ ionophore A23187. These results suggest (1) that atrial natriuretic hormones may play an important role in the nervous system, and (2) that cultured neural cells may be useful tools in the elucidation of the mechanisms of action of these hormones.