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Biomedical subjects

W Dick

Publications and source records attributed to W Dick.

At least 199 records · Page 11Linked to original sources
PubMed1985

[Artificial respiration technics].

In general there are two distinguishable methods of artificial ventilation: assisted spontaneous ventilation and controlled ventilation. Spontaneous ventilation can be supported by CPAP or PEEP, in order to improve oxygenation, and by IMV to improve CO2 elimination. Furthermore, high frequency low pressure ventilation may be used versus low frequency high pressure ventilation. Conventional IPPV may be supported by continuous endexspiratory pressure. In special cases IRV may be applied. High frequency low pressure ventilation methods may be used intra- and postoperatively as well as post-traumatically.

Humans↗
PubMed1985

Evidence for nonspecific induction of beta-lactamase in overproducing variants of Enterobacter cloacae and Citrobacter freundii.

Induction of chromosomally mediated beta-lactamases was studied in clinical isolates of Enterobacter cloacae and Citrobacter freundii. Whereas isolates resistant to ampicillin and cefoxitin exhibited an inducible enzyme, those sensitive to both agents did not. Cefoxitin and above all imipenem proved the most efficacious enzyme inducers. Variants among these inducible isolates which produced large amounts of beta-lactamase could be selected in the presence of cefamandole. In each of these selected variants constitutive enzyme production was markedly enhanced by induction, even with compounds lacking induction potency for the corresponding wild strains. Moreover, these variants could also be induced non-specifically, i.e. by non-beta-lactam compounds. Production of large amounts of enzyme was associated with resistance to all available beta-lactam compounds.

Anti-Bacterial Agents↗
PubMed1985

A new device for internal fixation of thoracolumbar and lumbar spine fractures: the 'fixateur interne'.

A new system of operative fixation of thoracolumbar and lumbar spine fractures is presented: the 'fixateur interne' (F.I.). From a posterior approach long Schanz screws are inserted through the pedicles into the body of the two vertebrae just adjacent to the lesion and connected by th threaded F.I. rods. By tightening the nuts the Schanz screws are fixed in all directions. The advantages of the F.I. system are: excellent reposition by the long lever-arm of the Schanz screws, immobilization of only two segments and therefore good mobility of the residual spine, stability against flexion forces better than is obtained with Harrington distraction rods, additional rotational stability, and fixation in lordosis or kyphosis as is desired. The F.I. does not act as a four point bending system like all other dorsal spine instrumentation systems, but provides stability in flexion by itself. Therefore it can be Used independently of the condition of all ligaments (including the anterior longitudinal ligament) and of the posterior wall of the fractured vertebrae, and there is no need to fix more than the two immediately adjacent vertebrae, thus avoiding the often painful and cumbersome iatrogenic loss of lumbar lordosis and of mobility and permitting early mobilization of the patient. Experience with the first 45 patients is very promising.

Bone Screws↗
PubMed1985

An enzymatic assay for monitoring serum, cerebrospinal fluid, and urine concentration of beta-lactam antibiotics.

August 29/October 24, 1984 An enzymatic assay for the determination of the concentrations of various beta-lactam antibiotics in serum, urine, and cerebrospinal fluid samples is described. Recently developed beta-lactam derivatives are used as competitive inhibitors of the breakdown of the labile coloured beta-lactam compound PADAC, which serves as the substrate for the various beta-lactamases. Under the conditions of the assay, there is effectively no interference due to the matrix. Moreover, the assay is not influenced by other antibiotics such as aminoglycosides, macrolides, ansamycines, tetracyclines, fusidic acid or fosfomycin. The C.V.s for within-run precision ranged from 3.7% to 4.4%, depending on the beta-lactam derivative. The sensitivity of the assay is at least comparable with that of conventional procedures. Excellent correlations were observed between the enzymatic and the microbiological procedures; correlation coefficients: r = 0.988 for 22 imipenem samples, r = 0.968 for 16 cefotaxime samples, and r = 0.989 for 16 piperacillin samples routinely sent to our laboratory.

Anti-Bacterial Agents↗
PubMed1985

Cefpirome (HR 810): lack of selection of beta-lactamase overproducing variants.

With respect to the selection of beta-lactam-resistant variants marked discrepancies between the recently developed cephalosporin HR 810 and other recently developed cephalosporins could be observed: beta-lactam resistant subpopulations did not emerge during a 16-hour culture in the presence of the 20-fold minimal inhibitory concentration in a clinical Enterobacter cloacae isolate (2240/81) in contrast to cefoperazone, cefotaxime, ceftriaxone and ceftazidime. Breakdown of the antibacterial agents during the 16-hour period as evaluated by monitoring their levels in the medium was not responsible for selection of beta-lactam-resistant subpopulations. The study of affinity of various cephalosporins to the chromosomally mediated beta-lactamase of E. cloacae strain 2240/81 revealed low affinity of HR 810 to the enzyme (Ki amounted 4.4 X 10(-3)M). It is suggested that the low affinity of this new agent to the E. cloacae enzyme plays a major role in the lack of selection of resistant subpopulations.

Cephalosporins↗
PubMed1985

[Sodium bicarbonate administration in cardiopulmonary resuscitation. Results of an animal experimental study].

One minute following electrically induced ventricular fibrillation, 12 anaesthetized pigs (hybrids between German and Belgian pedigree swine of 29 kg average body weight) were resuscitated for 30 min with a mechanical thorax compressor and ventilator. Six animals were given 1 mval sodium bicarbonate per kilogram body weight via a central venous line during the first ten minutes of resuscitation, and then 0.5 mval/kg body weight during both of the remaining ten minute intervals. The remaining 6 animals served as control group. In the control group constant volume ventilation led to a fall in the arterial partial pressure of CO2 because perfusion was diminished in relation to ventilation and despite the slowly developing metabolic acidosis this initially led to an increase in pH. At the end of the period of observation an arterial base deficit of 10 mmol/l was measured. Infusion of sodium bicarbonate led to a metabolic alkalosis and to an arterial base excess which at 10 min reached a maximum value of 13.8 mmol/l. In the bicarbonate group serum osmolality rose as a result of the sodium application from 293-334 mosm/l. In contrast, the osmolality of the control group only rose to 309 mosm/l.

Animals↗
PubMed1985

[Serum lysozyme level in children with acute leukemia and malignant diseases].

Serum lysozyme activity was measured in samples from 65 children with acute lymphatic and myelogenous leukemia, solid tumors and malignant lymphoma in comparison with 45 healthy children. All children with acute lymphatic leukemia (ALL) had significantly reduced levels of lysozyme before starting therapy compared with a control group (p less than 0,01). Children with ALL in complete remission had lysozyme levels comparable to normal children, while children with ALL in relapse showed pathological low levels again. Children with acute myelogenous leukemia (AML), solid tumors and malignant lymphomas had higher lysozyme concentration before therapy than healthy children. Determination of lysozyme activity in children with acute leukemia and malignant tumors is of value for diagnosis and to control the effect of therapy.

Child↗
PubMed1985

[Current diagnostic possibilities in hereditary angioedema and acquired angioedema].

Amidolytic assays for the determination of C1 esterase inhibitor have been proposed some years ago; however, the substrates employed lacked sensitivity. The recent development of a C1 esterase-sensitive substrate (N-alpha-methoxycarbonyl-l-lysyl(epsilon-CBO)-glycyl-arginyl-4-nit roanilide) provides a method that can be routinely used. Any interferences with other plasma proteases could not be observed. Normal range was ascertained to be 1.48 +/- 0.23 kU/l; within-run precision revealed C.V.'s of 1.74% (for the normal range) and 7.3% (for the pathological range). This method can be considered most suitable for functional determination of C1 esterase inhibitor and is superior to the determination of antikallikrein activity. To point out to the diagnostic relevance of a functional C1 esterase inhibitor assay some examples are illustrated.

Angioedema↗
PubMed1985

[Lysozyme in children with acute and chronic inflammatory intestinal diseases].

Fecal lysozyme excretion was determined in two hundred children and adolescent. In sixty three infants with enteritis due to Rotavirus the fecal lysozyme level was found to be significant higher than in the feces of a group of healthy infants (p less than 0.01). Elevated fecal lysozyme excretion could be detected in patients with untreated Crohn's disease. After treatment with Salazosulfapyridine, Prednisone and elemental diet during six week a significant drop in fecal lysozyme level was observed (p less than 0.01). In eighteen adolescent with Colitis ulcerosa and Crohn's disease the lysozyme level of colonic mucosa was found to be significant higher than a control group (p less than 0.01). The fecal lysozyme excretion can be used as an indicator for the clinical activity of the disease, as a control for therapeutic efficiency and a marker for a relapse.

Adolescent↗
PubMed1985

[The behavior of plasma histamine levels following peridural morphine administration].

One of the frequently reported side effects following epidural morphine administration in clinical trials is a generalized pruritus of several hours duration. Since histamine can elicit pruritus we investigated the plasma histamine levels following epidurally applied morphine (0.05 mg/kg) in 10 urological patients. Plasma histamine levels were determined as an indicator of histamine release. Indeed, in 2 of 10 patients plasma histamine concentrations rose to 2 ng/ml. 5 of 6 criteria for establishing histamine release were fulfilled in both cases. Minor clinical symptoms appeared only in one patient (one single wheal of 1 cm diameter, metallic taste), but no symptoms at all in the other. Considering the low dose of the analgesic and the relatively high incidence of histamine release (2/10) the result of this prospective study seems worth to be emphasisized and followed-up in further studies. Pruritus did not occur in any of the patients, the role of histamine in its pathogenesis is now becoming more doubtful.

Aged↗
PubMed1985

The influence of ketamine on both normal and raised intracranial pressure of artificially ventilated animals.

The effect of two different doses of ketamine, 0.5 mg kg-1 body weight, and 2.0 mg kg-1 body weight, on intracranial pressure and cerebral perfusion pressure were investigated in 21 young pigs (26-34 kg) under controlled artificial ventilation. Three groups each containing seven animals were studied: Group 1. Initially normal blood pressure and an intracranial pressure within the normal range (10.7 mmHg). Group 2. Normal blood pressure and increased intracranial pressure caused by inflating an epidural balloon (29.2 mmHg). Group 3. Increased intracranial pressure (32.7 mmHg) and mean arterial pressure reduced by approximately 30% through controlled haemorrhage. There was no increase in intracranial pressure from either normal or initially increased values. This applied to animals with normal blood pressure values and also to those in haemorrhagic shock. This observation can be explained by the lack of an increase in PCO2 under controlled ventilation. During haemorrhagic shock cerebral perfusion pressure fell significantly as a result of the fall in mean arterial pressure. This particularly applied to the 2.0 mg kg-1 dose of ketamine. We therefore consider volume substitution to be essential in this situation.

Animals↗
PubMed1985

[Anesthesia-related maternal mortality during labor. Results of a survey in the Federal Republic of Germany 1971-1980].

In order to obtain figures on the anaesthesia related maternal mortality in the Federal Republic of Germany, 707 hospitals have been addressed via questionnaire. Hospitals where obstetric departments and anaesthetic departments as well were available, were investigated for maternal mortality, anaesthetic requirements, and the complications which led to the maternal deaths during the period of 1971-1980. 38% (259 general hospitals and 10 university hospitals) responded; the geographical distribution seemed to be representative. The average maternal mortality rate was at 0.21%, which ranged from 0.21% for general hospitals to 0.16% for university hospitals. The overall anaesthesia related maternal mortality was around 6.4%. 20 of the reported 21 maternal deaths occurred under general anaesthesia and 1 under local anaesthesia; 17 patients died during caesarean section and 4 during vaginal delivery. The main complications which led to the maternal deaths were cardiac arrest and aspiration of gastric content with 38,1% each and convulsions with 4.8%. In 19% of the total maternal deaths the causes could not be determined. The importance of obstetric centres and of controlled anaesthetic methods delivery will be discussed on the basis of these and other figures which have been reported in the literature.

Anesthesia, Conduction↗
PubMed1985

[Intubation with the new ultra thin flexible fiberoptic scope in small children with congenital ankylosis of the temporomandibular joints].

Management of anaesthesia and intubation using a flexible endoscope of the ultra-thin generation (external diameter on the distal end 2.7 mm) of brother and sister with congenital ankylosis of the temporomandibular joint is described. Sedation was provided with ketamine while maintaining spontaneous breathing. Alternative methods to overcome difficult intubation in infants and small children with consideration of their specific anatomical conditions are discussed. Insertion of a fiberoptic endoscope through the endotracheal tube in the age group reported here was not possible hitherto. The new ultra-thin generation of flexible fiberscopes now makes it possible to perform direct fiberoptic intubation of infants and small children.

Ankylosis↗
PubMed1984

[Osteosynthesis of severe injuries of the thoracic and lumbar spine with internal fixation].

From a posterior approach long Schanz screws are inserted through the pedicles into the bodies of the two vertebrae just adjacent to the lesion and connected by the threaded Fixateur-interne-rods. By tightening the nuts the Schanz screws are fixed in all directions. The advantages of the F.I.-system are: excellent reposition by the long lever-arm of the Schanz screws, immobilization of only two segments avoiding the iatrogenic loss of mobility and lumbar lordosis, stability against flexion forces better than with Harrington distraction rods, additional rotational stability.

Fracture Fixation, Internal↗
PubMed1984

The early use of positive end expiratory pressure (PEEP) ventilation in emergency medicine, and some experiments on pigs.

The effects on near drowning of young pigs of positive end expiratory pressure and zero end expiratory pressure were studied. The arterial PO2 and blood gases were examined during recovery from near drowning and after haemorrhagic shock. The cardiovascular parameters were measured after shock. The findings were considered in relation to the use of positive and expiratory pressure in patients. It was recommended that it be only administered by experienced staff in hospitals, and should not exceed 10 mbars, while 5 mbar was adequate and avoided complications in most cases.

Animals↗
PubMed1984

Nonspecific induction of beta-lactamase in Enterobacter cloacae.

Induction of beta-lactamase was monitored in a strain of Enterobacter cloacae exhibiting high resistance to most beta-lactam antibiotics. Large amounts of the enzyme were induced not only in the presence of beta-lactams, but also in the presence of other bicyclic molecules such as folic acid, thiamin, tryptophan or haemin. Moreover, complex media (such as Trypticase soy broth and Schaedler's broth) and various body fluids (serum, pleural fluid and cerebrospinal fluid) also possessed considerable induction potency. Neither 'specific' induction (by beta-lactams) nor 'non-specific' induction (by other bicyclic compounds) could be augmented by addition of exogenous cAMP. These findings indicate that inducible beta-lactamases deserve more attention, above all with respect to the development of resistance against third-generation cephalosporins.

Anti-Bacterial Agents↗
PubMed1984

Influence of spontaneous and inducible beta-lactamase production on the antimicrobial activity of recently developed beta-lactam compounds.

The activity of 9 recently developed beta-lactam compounds was evaluated in 185 ampicillin-resistant isolates of Enterobacteriaceae. Moreover, in all strains, spontaneous and inducible beta-lactamase production was quantified and correlated with the minimal inhibitory concentration (MIC) of each compound. In most species, no correlation could be observed between spontaneously produced beta-lactamase and the MICs, with the only exceptions of Serratia spp. and Morganella morganii isolates for methoxyimino cephalosporins and azthreonam. On the other hand, the increase of MICs of third-generation cephalosporins and azthreonam correlated well with the total amount of enzyme produced. With respect to temocillin and the penem compound Sch 29 482, there was a significant correlation of enzyme production and MICs only among the Citrobacter spp. isolates. It can be assumed that the effectiveness of the new agents is not only due to the low rate of hydrolysis, but also to the rapid binding to the lethal target.

Anti-Bacterial Agents↗