Search PubMedSearch

Biomedical subjects

W Lorenz

Publications and source records attributed to W Lorenz.

At least 19 recordsLinked to original sources

Intravenous morphine and nalbuphine increase histamine and catecholamine release without accompanying hemodynamic changes.

Patients receiving intravenous morphine at doses of 0.3 and 1.0 mg/kg for general anesthesia have been reported to show significant elevations in plasma histamine that are associated with hemodynamic changes. We undertook a prospective, randomized, double-blind trial in which 0.15 mg/kg morphine or 0.3 mg/kg nalbuphine was administered intravenously to normal volunteers. Thirteen of 15 subjects receiving morphine and 10 of 14 subjects receiving nalbuphine had elevations in plasma histamine levels and symptoms of histamine release within 5 minutes of drug administration. Six subjects in the morphine group and five in the nalbuphine group exhibited levels of plasma histamine > 2.0 ng/ml, but these levels were not associated with hemodynamic changes and occurred 10 to 15 minutes after drug administration. Our study suggests that the opiate-induced elevation of plasma histamine derives from cutaneous mast cells.

Adolescent

Incidence and clinical importance of perioperative histamine release: randomised study of volume loading and antihistamines after induction of anaesthesia. Trial Group Mainz/Marburg.

Although histamine release is recognised as a common event during anaesthesia and surgery, few clinicians judge the resultant cardiorespiratory disturbances serious enough to warrant prophylaxis with antihistamines. We have assessed the incidence and importance of histamine release in a randomised 2 x 2 factorial study. 240 patients representing a routine throughput of major general surgery were studied during a standardised induction of anaesthesia and preoperative loading of the circulation with either Ringer solution or Haemaccel-35, with or without antihistamine prophylaxis with dimetindene (H1) plus cimetidine (H2). Cardiorespiratory disturbances were graded as detectable, clinically relevant, or life-threatening from observers' records of the anaesthesia and the actions taken by the anaesthetists. Disturbances that were accompanied by significant rises in plasma histamine were further designated histamine-related, and those that were not were designated histamine-unrelated. Anaesthetists, observers, and designators were blinded to whether or not the patients had received antihistamines and to which solution was used for circulatory volume loading. Clinically relevant or life-threatening histamine-related disturbances occurred in 8% of the patients who after induction of anaesthesia received Ringer without antihistamines, in 26% of those who received Haemaccel without antihistamines, and in 2% or less of those who received antihistamines (p < or = 0.0001). There were 4 life-threatening histamine-related disturbances, all in patients who received Haemaccel without antihistamines (p < 0.01). Histamine-unrelated disturbances occurred in 16% overall, with no obvious effect of Haemaccel or antihistamines. The histamine-related disturbances under anaesthesia were remarkable for their severity (even with small rises in histamine concentrations), for the prevalence of bradycardia, and for the absence of skin signs. Their likelihood and severity were increased in patients with tumours. The results of the trial make a case for routine prophylaxis with antihistamines as part of anaesthetic management.

Adolescent

Time sequence of histamine release and formation in rat endotoxic shock.

Increased histamine release and formation (induced histamine) are two hypotheses considered in the pathogenesis of endotoxic shock development. To prove both hypotheses a sequence of four randomized controlled studies in rats was performed. Histamine release was measured indirectly as a decrease in tissue-histamine contents (lung, liver, spleen, stomach); histamine formation was estimated directly as an increase in histidine decarboxylase (HDC) activity in the same organs. Changes in contents and enzymatic activities were determined 4 and 8 h after shock induction; in addition, at the time of death, the activity of HDC was measured in heart, kidney, and small intestine. 4 h after shock induction, there was a significant decrease in the tissue-histamine content as measured only in the liver, with the same trend in lung and spleen. 8 h after endotoxin application, however, histamine concentration increased in the liver (significantly p < .05) and lung compared to the NaCl control group. The manifestation of changes in HDC activity in various organs was selective (i.e., not all organs showed alterations), not uniform (decreased as well as increased activities were measured), and time-dependent (no increase in HDC activity in animals dying at > 20 h). At 4 and 8 h, only the liver showed a strong increase in HDC activity which can explain the increase in histamine content. In lung, spleen, and stomach, a significant decrease occurred. The results on histamine release and formation let us conclude that histamine is involved in the pathogenesis of endotoxic shock development.

Animals

Are hypotension and rash after atracurium really caused by histamine release?

A prospective, randomized, double-blind study was performed in 40 patients (ASA class I-III) treated with atracurium to ascertain whether histamine release caused hemodynamic or cutaneous changes. The treated group of 20 patients was premedicated with the H1 antagonist dimetindene (0.2 mg/kg) and the H2 antagonist ranitidine (1.25 mg/kg); the control group of 20 patients received saline. Six minutes after the induction of anesthesia with thiopental/fentanyl, patients received atracurium 0.5 mg/kg over 5 s. Plasma histamine levels were measured fluorometrically 5 min after administration of thiopental/fentanyl and 2 and 5 min after atracurium. Arterial blood pressure and heart rate were recorded every 2 min. Histamine levels (0.24 ng/mL) did not change significantly after thiopental/fentanyl. In the control group, 2 min after injection of atracurium, plasma histamine levels were 0.76 +/- 0.76 ng/mL, and in the antihistamine-treated group, 0.39 +/- 0.24 ng/mL (P < 0.05 control versus treated), suggesting that pretreatment with antihistamines may attenuate atracurium-induced histamine release. Systolic and diastolic blood pressure decreased significantly in both groups after thiopental (P < 0.05), but did not decrease further after the administration of atracurium. There were cutaneous manifestations in 7 of 20 patients in the control group and in none of the 20 patients treated with H1 and H2 antagonists (P < 0.0005). We conclude that atracurium caused modest histamine release in our patients but that the decrease in arterial blood pressure may have been due, in part, to thiopental. Cutaneous manifestations of histamine release did not correlate with hemodynamic events or with plasma histamine levels, but were prevented with antihistamine pretreatment.

Adolescent

Granulocyte colony-stimulating factor prophylaxis before operation protects against lethal consequences of postoperative peritonitis.

BACKGROUND: Postoperative peritonitis has a high mortality in human beings. It is accepted that cytokines are important mediators in pathophysiology of sepsis. The recent failure of clinical trials increased the necessity to proof new drugs in more clinically relevant animal models. The aim of this study was to examine the effect of granulocyte colony-stimulating factor (G-CSF) in addition to an antibiotic in postoperative peritonitis. METHODS: Dose-response curves and experimental conditions were developed in a total of 295 rats. The main experiment included three groups: control animals receiving a fecal inoculum, a group treated with antibiotic, and a third group receiving G-CSF in addition to the antibiotic. The main outcome was death, but in addition, serum tumor necrosis factor (TNF) level was determined. RESULTS: The mortality rate of 60% in antibiotic treated animals was considerably reduced by G-CSF to 20%. All animals of the control group died during the observation period of 120 hours. A correlation between TNF levels and mortality rate was observed. In G-CSF treated animals total suppression of TNF serum levels was accessible in contrast to the others. CONCLUSIONS: In a clinically relevant animal model G-CSF was effective as an additional concept of prophylaxis. These data are promising toward clinical trials.

Animals

Perioperative nonspecific histamine release: a new classification by aetiological mechanisms and evaluation of their clinical relevance.

As a consequence of the performance of a randomized controlled clinical trial on perioperative histamine release and cardiovascular and respiratory disturbances, several types of increases in plasma histamine had to be distinguished instead of only two which existed at the beginning of the study: drug-induced allergic and pseudoallergic reactions. First of all, the new classification by aetiology (clinical epidemiology) was derived from a meta-analysis (secondary analysis) of the most recent literature. According to that histamine release in the perioperative period has several, different causes and is involved in several, different disease manifestations. A clear distinction (classification), however, is necessary if histamine release as an unwanted (adverse) effect has to be recognized, value judged according to its clinical relevance and therefore also prevented by histamine antagonists. Histamine release by neuro-endocrine and neuro-inflammatory mechanisms, cytotoxic histamine release and local, cytokine induced histamine release have been distinguished from pseudoallergic histamine release, but its functions are not yet clear. It has been analysed in prospective trials which used special clinical situations as models: patients on a normal ward or before and during upper GI endoscopy without premedication, but also in specific phases of laparoscopic cholecystectomy (trocar phase and dissection phase). Their existence in the clinical reality is now very likely, but new trials must investigate the pathophysiological effects such as in metabolism, coagulation, pulmonary haemodynamics (shunt volume) and gastric acid secretion. Histamine release by pseudoallergic mechanisms, however, was identified in the very vulnerable post-induction phase of anaesthesia up to skin incision. Its incidence was much higher than ever expected and its clinical relevance was demonstrated by the severity of reactions and the intervention strategies of the anaesthetists who were blinded concerning the type of the plasma substitute given and the prophylaxis with antihistamines. Pseudoallergic histamine release was clearly unwanted (adverse). Its occurrence in the other phases of anaesthesia has to be further evaluated in the tedious procedure of data analysis of the Mainz-Marburg-trial. The overall incidence of histamine release in the trial was so incredible high (72% of all patients, some of them with up to 4 episodes of histamine release) that a distinction between pseudoallergic (unwanted) and other types of histamine release (possibly less unwanted or even beneficial) is urgently needed. In the phase of steady state (maintenance) of anaesthesia the H1-(+)H2-prophylaxis was highly effective. Further analysis must show whether this is also the case during the phases of induction of anesthesia.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult

Histamine release after injection of benzodiazepines and of etomidate. A problem associated with the solvent propylene glycol.

Many drugs, especially when given in rapid sequence can cause histamine release. Ten healthy volunteers were premedicated with diazepam 10 mg.70 kg-1 i.v. and lormetazepam 1 mg.70 kg-1 i.v., respectively, 30 min prior to etomidate 0.15 mg.kg-1 i.v. in a single-blind, crossover study. The benzodiazepine lormetazepam and the hypnotic etomidate caused distinct increases in histamine plasma levels in two subjects. Maximal histamine levels after lormetazepam were 2.05 and 2.7 ng.ml-1, and after etomidate 1.85 and 3.2 ng.ml-1, respectively. Both drugs are solved in propylene glycol, a solvent that conveys very high osmolality (lormetazepam 6,750 mosm.kg-1, etomidate 4,900 mosm.kg-1). Clinical symptoms, like tachycardia, hypotension or allergic reactions, associated with similar histamine levels were not seen in either case. This limited histamine release appears to be caused by osmotic damage of tissue and blood cells.

Adult

Isoprenylation of a protein kinase. Requirement of farnesylation/alpha-carboxyl methylation for full enzymatic activity of rhodopsin kinase.

The primary structure of bovine rhodopsin kinase (RK), which phosphorylates light-activated rhodopsin (Rho*), terminates with the amino acid sequence Cys558-Val-Leu-Ser561, a motif that has been shown to direct the isoprenylation and alpha-carboxyl methylation of many proteins (e.g. p21Ha-ras). Transient expression of RK in COS-7 cells revealed the presence of two immunoreactive protein species. Consistent with RK being modified by isoprenylation, interconversion of these two species was dependent upon isoprenoid biosynthesis in the cells. Moreover, a serine substitution for Cys558 resulted in a single RK species whose migration on sodium dodecyl sulfate-polyacrylamide gels was identical to that of RK from cells treated with mevinolin, an inhibitor of 3-hydroxy-3-methylglutaryl-coenzyme A reductase and, thus, of isoprenoid biosynthesis. This finding indicates that isoprenylation of RK requires Cys558. The electrophoretic mobility of isoprenylated RK synthesized in COS-7 cells was identical to that of RK from bovine rod outer segments, suggesting that RK is isoprenylated in vivo. RK was determined to be modified by a farnesyl moiety and alpha-carboxyl-methylated. A time course of Rho* phosphorylation revealed that non-processed RK is approximately 4-fold less active than wild-type RK. This is the first demonstration of isoprenylation/alpha-carboxyl methylation of a protein kinase, and suggests that these modifications markedly influence enzymatic activity in vivo.

Amino Acid Sequence

Effect of gastrin receptor blockade on endocrine cells in rats during achlorhydria.

Hyperplasia of the oxyntic enterochromaffinlike cells in response to long-lasting blockade of acid secretion is closely related to hypergastrinemia. In the present study, the effect of a specific gastrin receptor antagonist on proton pump inhibitor-induced changes on serum gastrin levels, mucosal height, as well as gastrin- and enterochromaffin-like cells was investigated in rats. The proton pump inhibitor BY 308 or the vehicle methylcellulose [Methocel (controls)] was administered for 2 weeks in the presence and absence of the gastrin receptor antagonist PD 136450 (CAM 1189). BY 308 significantly increased serum gastrin levels, gastrin cell density, and antral gastrin concentration. Concomitant application of PD 136450 did not alter this response. In the oxyntic stomach, mucosal height, enterochromaffinlike cell density, labeling index of enterochromaffinlike cells, and histamine concentration were elevated after treatment with BY 308. These increases were almost completely abolished by PD 136450. Even in normogastrinemic control rats, PD 136450 significantly decreased mucosal height of the oxyntic part of the stomach and the labeling index of enterochromaffinlike cells. The results show that (a) trophic effects of drug-induced achlorhydria are mediated by gastrin; (b) even in control rats (normogastrinemic), gastrin is a trophic factor for the oxyntic mucosa; and (c) antral gastrin cell hyperplasia in states of chronic achlorhydria is not mediated by gastrin itself.

2-Pyridinylmethylsulfinylbenzimidazoles

[Histamine release during induction of combination anesthesia using nalbuphine or fentanyl. Modulation of the reaction by premedication with promethazine/pethidine].

In a controlled clinical trial in patients admitted for general surgery (mainly abdominal and thyroid), histamine release following nalbuphine 1 mg/kg i.v. versus fentanyl 5 micrograms/kg i.v. was studied in the course of an otherwise routine induction with promethazine/pethidine as premedication 30 min before the opioids and alcuronium-flunitrazepam-thiopental 5 min later. Succinylcholine was given before intubation and further analgesia was obtained by repeated administration of either nalbuphine or fentanyl. Plasma histamine levels were measured by a specific fluorometric assay, heart rate and blood pressure were measured for assessing hemodynamics, and clinical signs of anaphylactoid reactions such as skin eruptions and arrhythmias were registered. RESULTS. Nalbuphine and fentanyl both released histamine with an incidence of more than 40%. In addition, nalbuphine potentiated the histamine release evoked by the sequential administration of alcuronium-flunitrazepam-thiopental in one complex of application. The incidence of histamine release in the nalbuphine group was 6/13 = 46%, in the fentanyl group only 1/11 = 9% (chi2 test, P less than 0.05). Furthermore, this study showed high histamine levels after succinylcholine and intubation in a relation to time of administration that suggested histamine release as a stress response to intubation. Finally, the incidence of histamine release after a second injection of the opioids was still 30%. A direct correlation between plasma histamine levels, hemodynamic changes, and skin reactions could not be shown. A detailed causality analysis with histamine release as a contributory determinant showed histamine release less detrimental to hemodynamic stability than the opposite, which had been expected. However, the promethazine administered 30 min before induction of anaesthesia had strong H1- and H2-receptor antagonistic activity and was given with optimum timing for H1- and H2-prophylaxis. CONCLUSION. The study demonstrated that histamine release during anaesthesia and surgery depends strongly on the time sequence of drugs and measures used. Histamine release is not predictable from studies in human volunteers alone; studies in patients have to be added. Histamine release is not always detrimental. H3-receptor-mediated effects after H1- and H2-prophylaxis may help patients to counteract the effects of a series of vasoactive drugs given during induction of anaesthesia.

Adult

Elements of the rabbit uteroglobin promoter mediating its transcription in epithelial cells from the endometrium and lung.

The rabbit uteroglobin gene is specifically expressed in certain epithelial cells of ontogenetically unrelated origin. In the endometrium, expression is restricted to the glandular and luminal epithelium and is inducible by progesterone and estradiol. In the lung, Clara cells lining the bronchiolar epithelium show constitutive expression of uteroglobin, which is modulated by glucocorticoids. To explore the molecular basis for this cell type specificity, we have transiently transfected the uteroglobin promoter region fused to the chloramphenicol acetyl transferase gene (CAT gene) in the endometrial cell line Ishikawa; in the human lung cell line NCI-H441, which shows morphological Clara cell characteristics; in HeLa cells; and in three fibroblast cell lines. The uteroglobin promoter efficiently drives expression of the CAT gene in Ishikawa and NCI-H441 cells, but not in HeLa and fibroblast cells. To identify the responsible elements we have analyzed progressive promoter 5'-deletion mutants and randomly generated linker scanning mutants spanning the sequence from -258 to -14 of the uteroglobin promoter. Transfection experiments reveal seven mutation-sensitive regions located around -30, -70, -95, -130, -190, -230, and -255. Several mutants display strong cell type-specific phenotypes. Most significantly, the integrity of the region around -190 is essential for full CAT gene expression in Ishikawa cells, but not in NCI-H441 cells.

Animals

[Preoperative risk assessment with the ASA classification. A prospective study of morbidity and mortality in various ASA classes in 2,937 patients in general surgery].

The value of ASA classification in assessment of perioperative risk, i.e. especially postoperative morbidity, was analyzed prospectively using the data of 2937 patients. The analysis took into account the criteria validity, reliability, and sensitivity. The incidence of post-operative morbidity after elective surgery rose from 3.9% in ASA class I to 36% in ASA class IV. Mortality was 0.6% in ASA class II, whereas 9.3% died in ASA class IV. Morbidity, mortality respectively, after emergency surgery was 10.2% in ASA class II compared to 69% in class IV, mortality 1.4% compared to 21.5%. Differences between the ASA classes were confirmed (p-value < 0.05) considering separate kinds of complications and different periods. Furthermore, ASA classification was a valuable reference to length of stay and severity of necessary therapy at the ICU.

Adult

[Pulmonary complications following surgical abdominal interventions. Identification of various risk groups].

Incidence and type of postoperative complications were prospectively analyzed in 2280 patients undergoing gastrointestinal surgery. 6.6% had one or more pulmonary complications requiring therapeutic intervention (2.3% pneumonia, 1.6% drained pleural effusions, 1.2% atelectases). Based on univariate and logistic regression analyses, the following parameters constitute high-risk patients with regard to pulmonary complications: Elective surgery (4.3%, 61/1428): anemia (7.2% pulmonary complications), pathological blood gas analysis (9.8%), preoperative hospitalization greater than 1 week (6.3%), blood loss under operations greater than 1000 ml (10.5%), length of the operation greater than 3 h (9.7%); emergency surgery (10.4%, 89/852): upper gastrointestinal operation (16.2%), age greater than 75 (19.9%), ASA IV/V (28%), anemia (19.6%), chronic bronchitis (19%), pathological blood gas analysis (26.6%), diabetes (16.5%), heart failure (18.2%), blood loss under operation greater than 1000 ml (24.3%), length of the operation greater than 2 h (15.4%). These results allow to distinguish between different levels of pulmonary risk.

Adolescent

Histamine and antihistamines in anaesthesia and surgery: from experimental pharmacology to clinical decision making.

The problem of whether antihistamines (histamine H1 + H2-antagonists) should be administered prophylactically before surgical interventions rose after animal experiments with hypnotics, opioids, muscle relaxants and plasma substitutes. It could, however, not be solved by classical biomedical research, but needed a heuristic problem-solving strategy. This strategy was formalized and in this way changed into a scientific structure by the thinking-aloud technique and the building of a decision tree with 9 nodes and various study designs to answer questions at particular decision nodes. The first question, whether the incidence of the reactions was high, was answered by several controlled clinical trials. The second question of life-threatening degrees of severity in single cases, was answered by a drug surveillance study. The third question, of whether severe incidents could always be avoided was answered by medical audit. The same was the case if death had to be considered as the final therapeutic failure. The fifth question was, "are the risks of histamine release comparable to other risks in the perioperative period?" They were--if thromboembolism, infection and stress ulcers were considered. The sixth and seventh questions referred to an experimentally and clinically effective prophylaxis. They were answered by animal and clinical studies with histamine antagonists, mainly with dimetindene and cimetidine. Undesired, adverse reactions to prophylaxis are rare since the drugs are given only once. Prophylaxis was calculated to be fairly cost-effective. Problem-solving strategies are very helpful in transferring facts and conclusions from experimental basic research to clinical decision making. This was convincingly demonstrated in antihistamine prophylaxis in anaesthesia and surgery.

Anesthesia