Search PubMed⌕ Search

Biomedical subjects

W Dietz

Publications and source records attributed to W Dietz.

At least 37 records · Page 2Linked to original sources
PubMed1996

Histamine release in sepsis: a prospective, controlled, clinical study.

OBJECTIVE: To determine if histamine release occurs in clinical sepsis. DESIGN: Prospective, controlled, clinical study. SETTING: Interdisciplinary intensive care unit and trauma ward. PATIENTS: Sepsis was confirmed in 20 patients (test group) by the criteria of the Veterans Administration Systemic Sepsis Cooperative Study Group (1987) and was verified by positive blood culture. In addition, patients were scored by the Elebute and Stoner Sepsis Score (1983), as modified by Dionigi et al (1985). A concomitant control group consisted of 20 postoperative patients with non-life-threatening trauma to the extremities and without signs of local or systemic infection. INTERVENTIONS: Observational study. Blood samples were collected for determination of plasma histamine concentrations in both groups at the time of study entry and on five succeeding days. MEASUREMENTS AND MAIN RESULTS: The patients were well matched, and the groups were not significantly different for all criteria known to influence histamine release. Comparison of the median values of each group on days 1 through 5 demonstrated significantly higher plasma histamine values in the test group on days 1 through 4, but these values were no longer significantly higher on day 5. While none of the nonseptic control patients achieved a plasma histamine concentration of > 1 ng/mL (the concentration of which was considered to be the pathologic cutoff point representing histamine release), these values (i.e., > 1 ng/ mL) were found in nine of 20 test group patients. In the test group, nonsurvivors (n = 9) had significantly higher plasma histamine concentrations than survivors (n = 11) throughout the whole study and eight of nine nonsurvivors showed a plasma histamine concentration of > 1 ng/mL. Correlation of plasma histamine concentrations on day 1 to sepsis severity (initial Sepsis Score) showed that all but one patient with a combined low Sepsis Score (< 20 points) and histamine concentration of < 1 ng/mL survived, while all patients with a Sepsis Score of > 20 points and histamine release (plasma histamine concentration of > 1 ng/mL) died. CONCLUSION: Increased histamine concentrations were shown to be causally associated (contributory determinant) with sepsis.

Adult↗
PubMed1995

Multiple laboratory comparison of the doubly labeled water technique.

A double-blind study was conducted to determine between-laboratory variability in the doubly labeled water method for measurement of total energy expenditure in humans, and to compare the accuracy and precision of three widely-used procedures for calculating rates of carbon dioxide production from the original isotope data. Eighteen laboratories from five countries participated in the study. All laboratories were provided with five water standards containing varying amounts of 2H and 18O, and in addition 11 laboratories were provided with urine and dose specimens from one (six laboratories) or two (five laboratories) healthy elderly subjects of normal height and weight undergoing a calorimetric validation of the doubly labeled water method. The data from the five water standards were analyzed to predict between-laboratory variability in the doubly labeled water technique in all laboratories. In addition, data from the subjects were analyzed using the "slope-intercept", "2-point" and "modified" methods of calculation. The results confirm that the doubly labeled water method can be an accurate technique for the measurement of energy expenditure in adult human subjects in some laboratories. However, there was substantial between-laboratory variability in the results and some laboratories returned physiologically impossible results. There was no significant effect of calculation procedure on the accuracy of the technique in this limited comparison, although the slope-intercept procedure appeared to be more susceptible to analytical error than the other procedures. The isotope standards analyzed by participants in this study will be made available to other investigators on request.

Aged↗
PubMed1994

Television viewing and violence in children: the pediatrician as agent for change.

Three decades of research suggest a causal link between exposure of children to violent images on television and subsequent violent behavior. The epidemic of violence in American society mandates a critical reappraisal of the televised images that children see. To slow the cycle of violence, pediatricians can: (1) Help shape parental attitudes toward children's viewing habits; (2) lobby for school systems to adopt curricula that include critical viewing skills; and (3) work with Congress, Federal regulators, television producers, and broadcasters to reduce the exposure of children to televised violence.

Attitude to Health↗
PubMed1992

Electrohydraulic-clamshell heart with energy converter inside the compliance reservoir.

Two new ideas on the electrohydraulic actuation of blood pumps have been combined. The first idea was to put the energy converters that propel the hydraulic fluid inside the compliance reservoir instead of having them separate. Compactness of the device and better cooling of the energy converter by the surrounding fluid are two major advantages of this approach. Secondly, we put the pumping membrane inside a clamshell that fits over a soft ventricle (1). The ventricle can be implanted first, after which the shell is slid over it. These two ideas have resulted in devices described in this paper. Preliminary in vitro and in vivo data are presented.

Animals↗
PubMed1992

Cavitation of mechanical heart valves under physiologic conditions.

Cavitation has recently entered the discussion of factors leading to blood and material damage after implantation of mechanical heart valves. Since direct evidence for this phenomenon cannot yet be demonstrated in vivo, an in vitro method had to be developed to permit the investigation whether cavitation actually occurs under (simulated) physiologic conditions and to clarify its clinical relevance. Previous studies have shown that different types of commercially available mechanical valves exhibit different tendencies to generate cavitation in vitro. The present study presents a test protocol for the assessment of cavitation generated by different replacement valves under simulated physiologic conditions. Comparative investigations were performed in order to transfer the in vitro results in vivo conditions. Although mechanical valves with an overlapping closing body/valve ring configuration tend to create cavitation earlier, cavitation could not be demonstrated for any investigated mechanical valve type under simulated resting conditions. The danger of continuous cavitation damage is therefore low. Certain valve types exhibit cavitation only at higher heart rates (more than 120-140 beats/min). Some valve types do not show cavitation even during heavy exercise. Based on mathematical models and experimental investigations, it is very likely that if cavitation does occur, blood and material damage may be expected.

Blood↗
PubMed1991

[Chronic purulent, draining, indolent pancreatic head pancreatitis with extrahepatic cholestasis].

Over the period of two weeks a 19-year-old man developed gradually increasing painless jaundice with dark urine and light-coloured soft stools (6-7 times daily), as well as loss of appetite, nausea and nagging itch. Biochemical tests indicated marked cholestasis (alkaline phosphatase 800 U/l, gamma-GT 206 U/l). Abdominal ultrasound examination revealed high-grade stenosis of the distal choledochal duct caused by an enlargement of the head of the pancreas and computed tomography confirmed a tumour in this location. Endoscopic retrograde cholangiopancreatography demonstrated filiform stenosis of the major pancreatic duct and prepapillary stenosis of the choledochal duct. Several needle biopsies failed to establish a definitive diagnosis. A Whipple operation was performed: the stomach was preserved but about 40% of pancreatic tissue resected. Histologically there was chronic suppurative pancreatitis of the head of the pancreas. The patient was symptom-free 6 months after the operation. The case illustrates that it is not always possible in a painless pancreatic tumour to distinguish between pancreatitis and malignant tumour.

Adult↗
PubMed1991

Controlled clinical trials and cross-sectional studies with plasma histamine measurements and histamine receptor antagonists: solving the problem of preoperative H1- + H2-prophylaxis by asking new questions?

The problem of a preoperative histamine H1- + H2 - prophylaxis was tackled by a group of new studies including randomized controlled clinical trials and cross-sectional studies with plasma histamine measurements and administration of H1- + H2 - antagonists to a control group. The first study demonstrated serial histamine release in the induction of anaesthesia up to 4 times in a single patient. Basal plasma histamine levels in resting subjects fell below 100 pg/ml during the time necessary for preparation of the surgical patient. Hence, spikes of elevated plasma histamine concentrations corresponded to histamine release. Although this histamine release very often was less than 1 ng/ml plasma histamine, it created systemic reactions after atracurium. The cut-off point of 1 ng/ml for such anaphylactoid reactions does no longer exist, also lower plasma levels are of patho-physiological significance. The clinical signs of histamine release in the induction of anaesthesia vary from drug to drug. Sometimes tachycardia and hypertension produce the highest likelihood ratio, sometimes tachy- and bradycardia, but no changes in blood pressure as in the case of atracurium. It is concluded that the reasons why histamine release in anaesthesia and surgery is so much underreported and under-estimated include the present paradigms about plasma histamine levels and the "classical picture" of histamine release. Both are no longer valid and need a re-assessment.

Adolescent↗
PubMed1991

[Stress ulcer or pneumonia: effect of prevention with H2 blockers on gastric juice pH].

In a study with 30 consecutive ventilated patients in a surgical ICU, the course of gastric pH was measured for 24 h. Cimetidine, 1.2 g per 24 h, was given to prevent stress bleeding. In the course of the evaluation period complete alkalization was found in only 4/30 patients (high responders); 10/30 patients showed no alkalization of gastric juice to above pH 4; and in 16/30 patients irregular pH changes were observed. These results suggest that the risk of developing pneumonia under this regimen will only be elevated in the high responder group. Although the alkalization of gastric juice was incomplete in our group, we saw no evidence of upper gastrointestinal bleeding. There is evidence that alkalization is not the only mechanism involved in successful prevention of bleeding.

Adult↗
PubMed1990

Plasma histamine levels in polytraumatized patients.

In a prospective clinical trial, plasma histamine levels were measured in 28 polytrauma patients on day 1, 5 and 14 after trauma. Only those subjects who died were drop-outs. All patients had severe polytrauma with at least 3 body regions involved. The median plasma histamine levels at all three time points were significantly higher than in patients with single trauma of the extremities or before selective orthopaedic surgery but still in the normal range (less than 1 ng/ml). However, all patients with plasma levels above 1 ng/ml on days 1 and 5 died, as did all patients with levels above 0.5 ng/ml on day 1. Thus the elevation of plasma histamine levels, for whatever reason, appears to be a prognostic factor for bad outcome in polytrauma patients.

Adolescent↗
PubMed1990

[Acute acalculous cholecystitis. A stress-induced complication].

The acute acalculous cholecystitis is a stress induced complication following surgery and trauma. A totally different disease is a large atonic gallbladder during parenteral nutrition. The symptoms of the acalculous cholecystitis are similar to acute cholecystitis in patients with cholelithiasis. The diagnosis can be very difficult, because in the postoperative period patients are usually very sick, treated with analgetic and antibiotic drugs and therefore the symptoms are mostly lacking or equivocal. Typical signs are fever and leucocytosis. An ultrasound scan should be performed at the intensive care unit. Although the disease is rare according to the literature, in future it may be diagnosed more frequently because of extended surgical intensive care, higher age of patients, modern methods of surgery and early ultrasound scans in equivocal cases. Having the possibility of postoperative and posttraumatic acute acalculous cholecystitis in mind, surgeons may be able to make the right diagnosis earlier than the pathologist.

Acute Disease↗
PubMed1987

[Ultrastructure of the distal ureter in congenital malformations in childhood].

Ultramicroscopical examinations were performed in ten children with reflux or obstructive megaureter. Resected parts of ureters were used for investigation in connection with reconstructive procedures. Whereas in case of an obstructive megaureter an intramural and juxtavesical localised functionless narrow ureteral segment is characterised by "nexus close contacts" and dissociation of muscle cells with interposition of fibrous tissue, progredient pathonexual changes in the sense of a reversible nexus-distension and irreversible nexus-rupture were seen in megaureters with reflux. Dissociation of muscle cells is combined with typical epithelial and adventitial pathological structures. In congenital megaureter, disturbances in the electric syncytium occur in connection with nexus injury, followed by pathological innervation. Interruption of muscle autonomy and innervation in the wall structure of such congenital ureteral malformations play an ominous role in the sequence of pathogenetic factors.

Child↗
PubMed1986

[Instructions for the complete preparation of the larynx].

A method of preparing the larynx in forensic cases is described especially when death occurs by strangulation (manually or using some form of ligature). After the usual dissection of the hyoid bone and the upper horns of the thyroid cartilage, the complete larynx is clipped and fixed in formaldehyde overnight. The first part of dissection after that is to cut away the thyroid gland and the remaining muscles in front of the larynx, except for the cricothyroid muscle and the esophagus and hypopharynx from the back of the larynx. The complete thyroid cartilage is dissected out, and then a horizontal cut is made through the cricoid cartilage. Median-sagittal halving of the remaining larynx completes the gross dissection. Arytenoid cartilages are exposed by dissection of the arytenoid muscles and opening the cricoarytenoid joints. Now all parts of the laryngeal skeleton and all articulations are examined, and all muscles and soft tissues are visible and can be clipped for histological examination.

Asphyxia↗
PubMed1986

Induced histidine decarboxylase in endotoxic shock: identification of the enzyme in rat liver and influence of its inhibitors on survival parameters.

The hypothesis of a causal relationship between a progressive and unrestrained increase of tissue histamine formation by activation of an inducible histidine decarboxylase (HDC) and lethality in endotoxic shock (Schayer's 'induced histamine concept') was tested in a standardized rat endotoxic shock model. Initial enzyme identification studies in the rat shock liver (8 hrs after endotoxin challenge) clearly demonstrate that the 'induced' histidine decarboxylase is an acid (specific) HDC. The succeeding randomized, controlled study with appropriate inhibitors of the enzyme, alpha-methyl-histidine (competitive inhibitor) and alpha-fluoromethyl-histidine (irreversible inhibitor) using doses of 2, 20 or 100 mg/kg showed no significant effect on the survival rate of rats in endotoxin shock. The survival rate of the non-treated endotoxin control group (NaCl) was 25%; all methylprednisolone treated rats (50 mg/kg) survived. Thus, the 'induced' histamine is not a predominant factor (necessary or sufficient determinant) for the lethal outcome in rat endotoxic shock. The protective effect of MP is not predominantly due to the inhibition of the 'induced' histidine decarboxylase. The use of HDC-inhibitors as the appropriate instruments for evaluation of the significance of this mechanism is discussed.

Animals↗
PubMed1982

Plasma histamine levels in patients in the course of several standard operations: influence of anaesthesia, surgical trauma and blood transfusion.

A prospective controlled clinical trial was conducted on changes in plasma histamine and catecholamine levels during 5 standard operations. This communication, as the first part of the trial, deals only with the feasibility of such a trial and the changes in plasma histamine levels. Elevated histamine concentrations corresponding to histamine-release responses of greater than 1 ng/ml occurred in 8 of 25 operations. In an explorative analysis these responses were associated with distinct phases of anaesthesia or the surgical procedure. Blood transfusion carried the risk of infusion of "free histamine" into the patient--especially when administered under pressure. Since during operations "free histamine" enters the circulation with a rather high incidence and may cause harmful effects, premedication with H1-+H2-receptor antagonists seems worth consideration.

Adult↗