Progestogens and membrane-initiated effects on the proliferation of human breast cancer cells.

OBJECTIVES: Evidence is accumulating that progestogens may play a crucial role in the development of breast cancer under contraception and hormone therapy in reproductive and menopausal women. Progesterone receptor membrane component 1 (PGRMC1) expressed in breast cancer may be important in tumorigenesis and thus may increase breast cancer risk. The aim of this project was to investigate the influence of progesterone and nine synthetic progestins on MCF-7 breast cancer cells overexpressing PGRMC1. METHODS: MCF-7 cells were stably transfected with PGRMC1 expression plasmid (WT-12). To test the effects of progestogerone (P) and the synthetic progestins chlormadinone acetate (CMA), desogestrel (DSG), drospirenone (DRSP), dydrogesterone (DYD), levonorgestrel (LNG), medroxyprogesterone acetate (MPA), nomegestrol (NOM) and norethisterone (NET) on cell proliferation, MCF-7 and WT-12 cells were stimulated with different concentrations (0.01-1 µmol/l). RESULTS: In MCF-7 cells, DRSP, DSG, DYD, LNG and NET increased the proliferation at 1 µmol/l, the effect being highest for NET with about 20%. In WT-12 cells, the same progestins, but additionally MPA, showed a significant increase, which was much higher (30-245%) than in MCF-7 cells. Here again, NET showed the highest proliferative effect. No effect was found for CMA, NOM and P. CONCLUSION: Some synthetic progestins trigger a proliferative response of PGRMC1-overexpressed MCF-7 cancer cells. The effect of progestogens on breast cancer tumorigenesis may clearly depend on the specific pharmacology of the various synthetic progestins.

Prognostic Relevance of Circulating Tumor Cells in Molecular Subtypes of Breast Cancer.

Circulating tumor cells (CTCs) can be detected in the peripheral blood of breast cancer patients with early and metastatic disease. Recent data suggest that immune pathologic characteristics between the primary tumor, metastatic colonies and CTCs are discordant and that CTCs possess an independent phenotype that is associated with prognosis and treatment efficacy. Large scale gene expression analysis has provided the possibility to stratify breast cancer according to the gene expression fingerprint of primary tumor tissue into five intrinsic molecular subtypes which can be associated with different clinical outcome. As a consequence of the different prognostic power of primary tumors' characteristics and CTCs several groups have started to investigate if CTCs might be disseminated differentially within these breast cancer subtypes. They determined the CTC number in immunohistochemical subtypes to validate if CTCs may provide differential and more specific prognostic information within each subtype. This review provides an overview of the outcome of some recently published data gathered from early and metastatic breast cancer.

Open channel and competitive block of nicotinic receptors by pancuronium and atracurium.

Mouse myotubes were used to investigate effects of the nondepolarizing neuromuscular blocking drugs pancuronium and atracurium on embryonic-type nicotinic acetylcholine receptor channels. Experiments were performed using patch-clamp techniques in combination with devices for ultra-fast solution exchange at outside--out patches. Application of 0.1 mM acetylcholine resulted in a fast current transient. When the peak amplitude was achieved, the current decayed monoexponentially due to desensitization. After application of drugs (pancuronium or atracurium), two different mechanisms of block were observed: (1) open channel block of embryonic-type nicotinic acetylcholine receptor channels after coapplication of blocker and acetylcholine, characterized by decrease of the time constant of current decay; (2) competitive block of embryonic-type nicotinic acetylcholine receptor channels by pancuronium or atracurium after preincubation of outside-out patches with the respective blocker. Different affinities of pancuronium (K(B) approximately 0.01 microM) and atracurium (K(B) approximately 1 microM) to embryonic-type nicotinic acetylcholine receptor channels were observed.

Block of nicotinic acetylcholine-activated channels of cultured mouse myotubes by isoflurane.

It is well known that volatile anesthetics cause muscle relaxation. A block of nicotinic acetylcholine-activated receptors (nAChRs) in staedy state by isoflurane was recently reported. Pulses of acetylcholine (ACh) were applied to outside-out patches from mouse myotubes using a system for ultra-fast solution exchange allowing the study of the block of nAChRs by isoflurane under conditions similar to the situation during synaptic transmission. Isoflurane in concentrations used during general anesthesia blocked approximately 50% of the receptors within 0.5 ms after application. The block of nAChRs could be partially relieved by application of high concentrations of ACh. Therefore, muscle relaxation and the reduction of the amplitude of postsynaptic currents by isoflurane may be caused by the block of nAChRs reported here.

The NO synthase inhibitors L-Name and L-NMMA, but not L-arginine, block the mammalian nicotinic acetylcholine receptor channel.

(1) Nitric oxide (NO) synthase inhibitors (NOS-I) such as L-Name (N(G)-nitro L-arginine methyl ester) and L-NMMA (N(G)-monomethyl L-arginine) may enhance anesthesia indirectly by inhibiting the NO pathway. Moreover, NOS-I interact directly with receptor proteins. In an animal study, L-NMMA potentiated muscle relaxants. (2) The present experiments investigate the effects of L-NMMA, L-Name, and L-arginine on the nicotinic acetylcholine receptor channel (nAChR) using patch clamp techniques and a piezo-driven application system. Both NOS-I appear to directly interact with the nAChR in the open as well as in the closed conformation. L-Arginine has no effect.

Central anticholinergic syndrome (CAS) in anesthesia and intensive care.

Many of the drugs used in anesthesia and intensive care may cause blockade of the central cholinergic neurotransmission. Acetylcholine is of significance in modulation of the interaction among most other central transmitters. The clinical picture of the central cholinergic blockade, known as the central anticholinergic syndrome (CAS), is identical with the central symptoms of atropine intoxication. This behaviour consists of agitation including seizures, restlessness, hallucinations, disorientation or signs of depression such as stupor, coma and respiratory depression. Such disturbances may be induced by opiates, benzodiazepines, phenothiazines, butyrophenones, ketamine, etomidate, propofol, nitrous oxide, and halogenated inhalation anesthetics as well as by H2-blocking agents such as cimetidine. There is an individual predisposition for CAS--but unpredictable from laboratory findings or other signs. Reports of postanesthetic occurrence of the CAS requiring treatment are not unanimous, varying between 1 and 40%. Differential diagnosis of the CAS includes disorders of glucose and electrolyte metabolism, severe hormonal imbalance, respiratory disorders (hypoxia, hypercarbia), hypothermia, hyperthermia and neuropsychiatric diseases (cerebral hypoxia, stroke, catatony, acute psychosis). The CAS may considerably impair the postanesthetic period especially when agitation is prevalent, which may endanger the patient or the surgical results. The diagnosis is confirmed ex iuvantibus by the sudden increase in the acetylcholine level in the brain. This is achieved with physostigmine, a cholinesterase inhibitor able to easily cross the blood-brain barrier. Its peripheral muscarinic effects are minimal. Postanesthetic CAS can be prevented by administration of physostigmine during the anesthesia procedure. During intensive care (IC), agitated forms of CAS may occur in patients undergoing mechanical ventilation, particularly during prolonged high-dose sedation. Artificial ventilation of such patients becomes very difficult and muscle relaxation may be necessary. In these cases of IC-CAS, physostigmine is of value and has proven beneficial during weaning from mechanical ventilation. Dealing with the CAS for more than a decade has improved knowledge of the central cholinergic transmission. For example, it can be said that CAS occurs alongside general anesthesia, being no more than a frequent side-effect. Furthermore, acetylcholine is involved in nociception through the endorphinergic and the serotoninergic systems. There is a close relation between the central cholinergic transmission and actions of nitrous oxide. Moreover, cholinergic transmission is involved in withdrawal from (among others) alcohol, opiates, hallucinogens and nitrous oxide. In some intoxications with psychoactive agents, physostigmine is useful for reversal of the central nervous symptoms of the acute intoxication itself. In addition it can be used for prevention of some withdrawal states. In

[Value of the injury severity score (ISS)]. / Zur Aussagekraft des Injury-Severity-Score (ISS).

The injury severity score (ISS) has been most widely accepted as a practicable method of classifying traumatised patients (ie., patients with accident injuries) according to the severity of their injuries, and has become more popular than all other comparable classification systems. By allocating the patients to different severity groups, it facilitates their classification in respect of prognosis. Over and above this, it enables comparison of patient groups of different hospitals. The authors investigated the validity of ISS classification by studying the case records of 432 patients in a traumatological intensive-care ward. They found good correlation between ISS score on the one hand, and lethality, requirements of banked blood during first-aid care and duration of treatment and artificial respiration of survivors on the other. However, the mean survival time of those patients who had died, did not reveal any connection with the severity of the injury. It is definitely impossible to arrive at any prognosis for an individual patient on the basis of his ISS classification. With increasing age, lethality after an accident increases even if the injury is less severe. The validity of ISS could be increased further if the age of the patients could be taken into account as well.

Circulating Tumor Cells in Early-Stage Breast Cancer.

Disseminated tumor cells (DTC) are routinely detected in bone marrow (BM) in 30-40 % of primary breast cancer patients. Positive BM status at the time of diagnosis as well as DTC persistence after therapy are strong independent prognostic factors. Since repeated BM aspirations are not well tolerated, detection of single tumor cells in peripheral blood (circulating tumor cells; CTC) have become of interest in recent years. CTC are found in 10-80 % breast cancer patients. Variability can be explained by stage of the disease and detection method. Emerging data have shown CTC to be of prognostic relevance for both, patients with primary and metastatic disease. The assessment of CTC in blood may become an important biomarker for prognostication and therapy monitoring. Determination of their molecular characteristics will enable specific targeting of minimal residual as well as metastatic disease. This review summarizes recent research and future perspectives.

Acid aspiration prophylaxis and caesarean section.

Acid aspiration syndrome still contributes to the few anaesthesia-related deaths in caesarean section. Although none of the numerous measures intended to prevent such fatalities is based on clear evidence, many different regimens are being used. As obstetric acid aspiration syndrome occurs mainly in general anaesthesia, using regional techniques wherever possible may be the most effective prophylactic measure.

Sevoflurane potentiates and blocks GABA-induced currents through recombinant alpha1beta2gamma2 GABAA receptors: implications for an enhanced GABAergic transmission.

BACKGROUND AND OBJECTIVE: The gamma-aminobutyric acidA receptor (GABAAR) is a target for anaesthetic agents. We investigated the interactions of sevoflurane with a recombinant GABAAR. Emphasis was on the mechanism of block, as relevant open-channel block by a volatile anaesthetic would possibly explain prolonged GABAergic postsynaptic currents. METHODS: The effect of sevoflurane on GABA-induced currents through recombinant alpha1beta2gamma2 GABAAR channels was studied (patch clamp; HEK293 cells). GABA 0.01 mM or 1 mM was applied alone or together with sevoflurane (0.05 mM to 5 mM). RESULTS: Currents elicited by GABA 0.01 mM were increased by low sevoflurane concentrations to 183% and decreased by high sevoflurane concentrations (> 1 mM) to 34% (P < 0.05). Ten- to 90%-rise times of the currents were reduced by sevoflurane concentration dependently. At GABA (1 mM), peak currents and 10-90%-rise times decreased with increasing sevoflurane concentrations. A transient current increase was induced by discontinuation of GABA and sevoflurane. Such rebound currents indicate a reversal of an open-channel block by sevoflurane. CONCLUSIONS: Sevoflurane (a) increases the apparent affinity of GABA to the GABAAR, as suggested by the decreased current rise times. This explains the enhancement of the currents induced by low GABA concentrations (0.01 mM). Additionally, sevoflurane (b) induces a picrotoxin-like open-channel block at the GABAAR. The reversal of the open-channel block elicits a delayed GABA response. These findings indicate at least two different sites of action of sevoflurane at this receptor that are both important for an enhanced GABAergic synaptic transmission.

Surveys on the use of regional anaesthesia in obstetrics.

Regional anaesthetic techniques in obstetrics have gained more and more importance during the last few years. Several surveys published recently show a remarkable increase in caesarean sections performed under regional anaesthesia, in many countries. Furthermore, epidural analgesia has proved to be one of the most effective methods of pain relief during vaginal delivery. Especially in patients at risk of an abdominal delivery, an epidural catheter already in place during labour can be used for consecutive caesarean section without delay and is used as a strong argument in favour of epidural anaesthesia. This article gives an overview of recent surveys of regional anaesthesia in obstetrics.

[Significance of upper gastrointestinal hemorrhage in patients with multiple injuries]. / Bedeutung der oberen gastrointestinalen Blutung bei polytraumatisierten Patienten.

The incidence, time of onset and course of clinically manifest upper gastrointestinal bleeding was analysed in 265 polytraumatized patients with an average "injury severity score" (ISS) of 31.5. Under standardized intensive-care treatment - including appropriate artificial ventilation; maintenance of a stable circulation; complete parenteral and earliest possible enteral nutrition; low-dose heparinization; sedation and analgesia as required; and intragastric administration of antacids - only two patients (0.8%) had clinically manifest upper intestinal bleeding and then only preterminally in the course of incurable multi-organ involvement, the bleeding being a component of multiple organ failure. The focus of stress-ulcer prevention should lie in a decrease of factors precipitating multiple organ failure, as well as in the carefully selective use of general intensive-care measures. The need of general systemic prevention with H2-receptor blockers and (or) pirenzepine is questionable.

[Maxillary sinusitis in intensive care patients]. / Sinusitis maxillaris bei Intensivpatienten.

Fever of unknown origin is a major diagnostic problem in traumatologic postoperative intensive care medicine. Even when other causes of fever (wound infection, pneumonia, intravenous catheter contamination) have been ruled out, purulent maxillary sinusitis is rarely considered as the initial focus. The maxillary sinuses of 46 patients admitted to a postoperative intensive care unit were examined using a mobile "A-Scan" ultrasonic scanner. Follow-up examinations were performed on a regular basis. As early as on the 5th day of treatment, the initially, most often nasotracheally intubated and artificially ventilated patients exhibited a high frequency of pathological ultrasonic results, whereas only 10 of the 46 patients within the study demonstrated normal findings throughout the follow-up examinations. As a rule, bilateral involvement was observed. When findings were initially unilateral, the nasally intubated side was most often affected. Early extubation, partial mobilisation and/or administration of antibiotics from the first day of treatment onwards did not prevent the occurrence of pathologic ultrasonic results. Fever and leucocyte count were found to be elevated to a higher level in patients with purulent sinusitis. Thus, affection of the maxillary sinuses appears to be a frequent accompanying disease in intensive care patients, and should therefore always be taken into consideration as the initial focus of fever of unknown origin.

[The early diagnosis of malignant hyperthermia--the place of end-expiratory CO2 monitoring]. / Frühdiagnose der malignen Hyperthermie--zum Stellenwert des endexspiratorischen CO2-Monitorings.

The authors report on the course of a fulminant malignant hyperthermia (MH) associated with laminectomy in a 29-year-old man who had been healthy up to that time. Succinylcholine and isoflurane were considered to be the causative triggering agents. Progression could be prevented due to an early suspicion raised by end-expiratory CO2 measurement: treatment was instituted immediately (Dantrolene 2mg/kg body weight, oxygen hyperventilation, external cooling, etc.) Serum creatine kinase increased up to almost 50,000 U/l associated with massive myoglobinuria. Residue-free restitution was achieved within a few days. Decisive for an early detection of MH is the routine performance of end-expiratory CO2 measurement which is definitely superior to temperature control and significantly reduces the time that elapses before treatment is initiated.

[Pharmacologic modification of vigilance in the postnarcotic phase-- naloxone or physostigmine?]. / Medikamentöse Beeinflussung der Vigilanz in der postnarkotischen Phase--Naloxone oder Physostigmin?

The usefulness of physostigmine in reversing post-narcotic depression after general anaesthesia is well proven; so is that of naloxone, a specific opioid analgetics antagonist, in reversing neuroleptic anaesthesia effects. Morphine-like analgetics are widely used as premedication agents, too; on the other hand, physostigmine reverses opioids as well as other psychotropic and narcotic agents. For that reason, positive post-narcotic physostigmine effects could be due to its anti-opioid potency as well. In a double-blind, randomised study, physostigmine and naloxone were evaluated using a clinically based vigilance protocol, and compared with saline solution. Naloxone did not have remarkable advantages as compared with placebo, while physostigmine led to a significantly higher level of vigilance; moreover, that level was reached sooner. The positive effects of physostigmine in restoring a sufficient level of vigilance after general anaesthesia are, in respect of our findings, unrelated to its antagonism to morphine-like analgetics.

[Physostigmine--recent pharmacologic data and their significance for practical use]. / Physostigmin--Neuere pharmakologische Befunde und ihre Bedeutung für den Einsatz in der Praxis.

Physostigmine is widely used for treatment of the central anticholinergic syndrome during recovery from anaesthesia. The drug is also very useful in treatment of intoxicated patients, in differential-diagnostic procedures of coma of unknown origin, and in restoration of vigilance after prolonged sedation for mechanical ventilation. Besides the specific central cholinergic action of physostigmine, several new pharmacological actions have now been established. Analgesic action is dependent on the interaction with the 5-HT (serotoninergic) system and is independent of narcotic or cholinergic agonists. The antianalgetic stress hormone, ACTH, also does not interfere with this action. Physostigmine does not interfere with the anaesthetic state when given during general anaesthesia. It attenuates several withdrawal states, especially alcohol delirium, opiate and nitrous oxide withdrawal syndromes. The drug may offer a protective mechanism against hypoxic damage of the brain and may also be beneficial in amnestic syndromes and sleep disorders. Physostigmine produces central and peripheral cardiovascular stimulation. It has been shown that physostigmine can be useful in prevention and treatment of postanaesthetic behavioural disturbances following anaesthesia with propofol. Number of indications for use of physostigmine has increased considerably.

[Air transportation of patients: a danger of hypoxic organ lesions?]. / Lufttransport von Patienten: Gefahr hypoxischer Organschäden?

As illustrated by two cases, a fall in alveolar oxygen pressure at high altitude, such as during transportation by plane, can cause hypoxic pulmonary failure, especially in patients with already impaired pulmonary or circulatory functions. Arterial oxygen saturation was recorded by pulse oximetry in 14 healthy volunteers and eight patients during air transportation. Oxygen saturation decreased with reduced cabin pressure. Decreased saturation for each 100 mm Hg reduction in cabin pressure was markedly greater in the patients than the healthy volunteers. Pulmonary and circulatory status should be assessed before air transport of patients and if necessary departure delayed. Oxygen ought to be added to inspired air with appropriate supervision in all acutely ill patients. Indications for endotracheal intubation before flight should be generously defined. Continuous pulse oximetry is noninvasive and highly informative. It is urgently recommended that air ambulances be equipped with them.

Dual action of isoflurane on the gamma-aminobutyric acid (GABA)-mediated currents through recombinant alpha(1)beta(2)gamma(2L)-GABA(A)-receptor channels.

Isoflurane (ISO) increased the agonist-induced chloride flux through the gamma-aminobutyric acid A receptor (GABA(A)R). This may reflect an anesthetic-induced increase in the apparent agonist affinity. A dual effect of anesthetics was postulated for both the nicotinic acetylcholine receptor (nAChR) and the GABA(A)R. We tested the hypothesis that, in addition to a blocking effect, ISO increases gamma-aminobutyric acid (GABA)-gated currents through recombinant GABA(A)R channels. HEK293 cells were transfected with rat cDNA for alpha(1),beta(2),gamma(2L) subunits. Currents elicited by 1 mM or 0. 01 mM GABA, respectively, alone, or with increasing concentrations of ISO, were recorded by using standard patch clamp techniques. ISO reduced the peak current elicited by 1 mM GABA. Currents induced by 0.01 mM GABA were potentiated by small ISO (twofold at 0.5 mM ISO) and inhibited by larger concentrations. Withdrawal of ISO and GABA induced rebound currents, suggesting an open-channel block by ISO. These currents increased with increasing concentrations of ISO. At large concentrations of ISO, the inhibitory effect predominated and was caused by, at least partly, an open-channel block. At small concentrations of ISO, potentiation of the GABA-gated currents was more prominent. This dual action of ISO indicates different binding sites at the GABA(A)R. The balance between potentiation and block depends on the concentrations of both ISO and GABA.

[Enflurane blocks ion current through the nicotinic acetylcholine receptor]. / Enfluran blockiert den Ionenstrom durch den nikotinischen Acetylcholinrezeptor.

AIM: The study investigates the influence of enflurane (EN) on macroscopic currents of the nicotinic acetylcholinergic receptor channel (nAChR). This ion channel is a representative member of the superfamily of ligand-gated receptor channels and is better characterized than all the other receptors in respect of structure and function. METHODS: For the experiments the patch-clamp technique was used to study the embryonic type of the nAChR expressed by cultured mouse-myotubes. Patch-clamp recordings were performed in the outside-out-mode from these preparations. To match the rapid desensitization kinetics of ligand-activated ion channels, a liquid filament switch technique was used for the application of agonists to the excised patches. This technique allows for change of solution within 300 microseconds. We used a saturating concentration of 10(-4) M acetylcholine (ACh), activating almost all available ion channels on a patch. Pulses of 10(-4) M ACh together with EN in different concentrations were applied repetitively. RESULTS: The current elicited by 10(-4) M ACh is reduced reversibly in a concentration-dependent manner by EN in clinically relevant concentrations: 1,44 x 10(-5) M EN inhibit about 10%, 1.44 x 10(-4) M 25%, 1.44 x 10(-3) M 35%, and 1.44 x 10(-2) M 75% of the ion flux (averaged results from 48 patches). EN decreases the time constant of the current decay. This acceleration of desensitisation kinetics is partly reversible if followed by application of 10(-4) M ACh. CONCLUSION: In this study we were able to show that EN reduces the currents of the ligand-gated embryonic-like nAChR in clinically relevant concentrations. Volatile anaesthetics are known to influence GABAA-, glutamate-, and glycine- activated receptors, which are members of the same family of ligand-gated receptor-channel units. Thus, the action of volatile anaesthetics on ligand-gated receptors may play a role in the mechanism of general anaesthesia. The interaction of volatile anaesthetics with nondepolarising neuromuscular blockers may also be based on this effect at the neuromuscular junction.

[EEG changes during sedation with gamma-hydroxybutyric acid]. / EEG-Veränderungen unter Sedierung mit gamma-Hydroxybuttersäure (GHB).

Gamma-hydroxybutyric acid (GHB) is a naturally occurring transmitter in the mammalian brain, related to sleep regulation and possibly to energy balance in diving or hibernating animals. It has been used for almost 35 years as an intravenous agent for induction of anaesthesia and for long-term sedation. Its convincing pharmacological properties, without serious adverse effects on circulation or respiration, are compromised by its unpredictable duration of action. This is not a major problem with long-term sedation during ICU treatment. GHB has been used with good results for sedation of patients with severe brain injury, where it compares favourably with barbiturates. In animal studies, it seems to possess a protective action against hypoxia on a cellular and whole organ level. However, in some experimental animals GHB has been shown to produce seizure-like activities, and the compound is being used to produce absence-like seizures. GHB has been used in our ICU for years to provide adequate sedation for patients under controlled ventilation or for patients fighting the respirator during spontaneous respiration. No serious side effects were observed in these patients, while in some patients under haemodialysis hypernatraemia and metabolic alkalosis developed; both were reversible after discontinuation of GHB and restriction of additional sodium input (Somsanit, the commercially available GHB preparation in Germany, contains 9.2 mmol sodium/g; the daily dose averages 20-40 g GHB, i.e. 180-370 mmol sodium). PATIENTS AND METHODS. In 31 patients after major abdominal surgery, sedation was established with GHB 50 mg/kg BW injected via perfusion pump over a 20-min period. No centrally acting medication had been given for at least 2 h. A computer-based multichannel EEG system (CATEEM, MediSyst, Linden) was used, allowing for fast Fourier transformation, spectral analysis and topographical brain mapping. EEG during induction of sedation was followed after a baseline EEG (10 min) had been recorded. Patients receiving long-term sedation were studied daily for an additional 15-min period. Corresponding well to the clinical findings, EEG pattern changed to a slow delta-theta or delta-only rhythm within 10 min of the start of injection. Alpha and beta power decreased, while delta activity exhibited an increase. All changes were most obvious in frontal and central areas of the brain. In about one out of three patients, a burst--suppression pattern developed. Since automatic processing of EEG may fail to detect special patterns like the looked-for 3/s spikes and waves, the raw EEG was analysed visually by an expert neurologist. Both processed and conventionally analysed EEG were free of any seizure-like electrical activity. CONCLUSION. We conclude that animal data may not apply to the use of GHB in humans, provided the dose is limited to the clinical needs. GHB is used in clinical practice in doses twice as high, or even higher, than the one we use for induction, without obvious side effects. However, the suppression of theta rhythm we observed in about half of the patients studied may indicate that even less than 50 mg/kg BW might be sufficient for adequate sedation.