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Biomedical subjects

J Hager

Publications and source records attributed to J Hager.

117 records · Page 7Linked to original sources
PubMedDate not supplied

Treatment of nosocomial infections in children undergoing antimicrobial chemotherapy.

Patients under immunosuppressive therapy with malignant diseases, malformations, premature infants or children after major surgical interventions and trauma are particularly susceptible to infections. In these patients nosocomial infections with multiply resistant organisms may occur despite broad spectrum antibiotic prophylaxis or antimicrobial chemotherapy of existing infections. In an open clinical study 31 infants and children with an overall 45 episodes of life-threatening hospital-acquired infections occurring under broad spectrum antimicrobial coverage were treated with imipenem/cilastatin alone or in various combinations. All the patients were immunocompromised. The most frequent single diagnosis was sepsis--documented by a positive blood culture--followed by nosocomial pneumonia, urinary tract infection and peritonitis. In seven patients an infection of implanted biomaterial was present which could not be controlled by the previously administered antimicrobial therapy. Imipenem/cilastatin was given in a dose of 50 mg/kg BW. Therapy was well tolerated, no side effects were observed. A total of 34 of 45 episodes could be successfully treated with imipenem/cilastatin alone or in various combinations. One child died from refractory candida sepsis; five further children died from the underlying disorder, the respective infectious complications having been controlled adequately. Treatment failures were due to infection with Candida albicans, Pseudomonas cepacia and resistant Streptococcus faecium. Imipenem/cilastatin proved to be a suitable antibiotic for the treatment of life-threatening nosocomial infections and reinfections in children.

Adolescent↗
PubMedDate not supplied

The use of methylmethacrylate as an external fixator in children and adolescents.

Methylmethacrylate has been used as an external fixator on 52 bones in 36 children and adolescents. There were 36 osteotomies and 16 selected fractures of long bones. The application of the acrylic cement onto 229 half-pins was performed with the use of flexible plastic tubes, in all but two patients. Union in the desired position was achieved in 51 bones. Delayed union occurred in one and required internal fixation. In the rest of the cases, there were only a few minor complications. The methylmethacrylate appears to be a stable fixator for osteotomized and fractured bones in young patients. The method is practical, easily performed, and of low cost.

Adolescent↗
PubMedDate not supplied

In vitro experiments on catheter-related infections due to gram-negative rods.

Although many complications may arise with the use of central venous catheters, catheter-related bacteremia is considered to be the most serious complication. Microflora on the patient's skin (coagulase-negative staphylococci, Staphylococcus aureus) is thought to represent the major source of microorganisms causing catheter-related infections. Gram-negative rods are increasingly observed as causative agents. We therefore performed an in vitro study to elucidate the pathogenesis of polymer-associated infections caused by enterobacteriaceae and nonfermenters and to study the resistance of polymer surface-grown gram-negative rods against antibiotics. Using a modification of the semiquantitative method for culturing vascular cannulas on solid media described by Maki et al., we studied the adherence of various gram-negative rods to 1-cm segments of silastic catheters, a material used for Port-A-Cath-systems. Organisms were obtained from the American Type Culture Collection (Escherichia coli, Klebsiella pneumoniae, Serratia marcescens, Pseudomonas aeruginosa, Enterobacter cloacae). All organisms but Klebsiella showed extensive irreversible adherence. Production of an extracellular slime substance was observed only with antimicrobially treated Pseudomonas. After 'infection', the silastic catheter segments were treated with various antimicrobial agents. The following antibiotics were used either individually or in combination: cefotaxime, ciprofloxacin, imipenem, fosfomycin and gentamicin. Despite the fact that the antibiotic concentrations used were many times greater than the respective MICs of the various antibiotics, none of the antibiotics tested succeeded in eliminating the organisms. E. coli was found to be the most susceptible organism. These in vitro data substantiate our clinical impression that it is hardly possible to successfully eliminate the colonization of central venous catheters with gram-negative rods by using the antimicrobial agents employed here.

Anti-Bacterial Agents↗
PubMedDate not supplied

Rotacor: a new rotary blood pump.

A new rotary blood pump was tested in calves for 6 hr. The pump consists of a rigid housing with a trochoidal internal surface, an inlet and outlet, and two lateral walls. A two-corner piston rotates on an eccentric shaft in a trochoidal path, thus creating a gap seal. The pump is driven by a water-cooled DC motor. For right ventricular assist, a cannula was inserted into the right ventricle through the right atrium, and into the left ventricle for left ventricular assist. From a total of 10 experiments, two left ventricular assists, two right ventricular assists, and three biventricular assists were evaluated. The pump produced a pulsatile flow of 3 L at 70 rpm. Energy requirements were 2.19 watts for left, 2.06 for right, and 7.26 for biventricular assists. Plasma hemoglobin remained as low as 10 mg/dl during monoventricular, and increased during biventricular assists to 20 mg/dl after 3 hr, when it started to chop again; after 6 hr it was 16 mg/dl. From these preliminary results it is concluded that this new type of blood pump may be suitable as a circulatory assist device.

Animals↗
PubMedDate not supplied

Functional heart replacement with the spindle pump: first results.

The spindle pump is a nonpulsatile blood pump with a double function, i.e., it works centrifugally and represses simultaneously. The first experiences with this type of pump used as a biventricular assist device in four short-term animal experiments (up to 13 hours) are described. It can be demonstrated that in cases of a normally beating heart, this BVAD decompresses both ventricles by 60-70%, while the aortic pressure is slightly increased; on the other hand, in case of ventricular fibrillation, the BVAD with two spindle pumps maintained the entire circulation, at an arterial pressure between 80 and 90 mmHg with a flow volume between 3.5 and 4 L/min.

Animals↗
PubMedDate not supplied

The spindle pump. Development of a nonpulsatile blood pump for assisted circulation.

The spindle pump is a combined working nonpulsatile blood pump, i.e., a centrifugally propelling device. This special concept was chosen to tackle the main problems of nonpulsatile pumps, such as thromboembolic complications, sealing difficulties, and traumatic hemolysis. The first two of these problems were relatively simple to solve compared with the third problem--traumatic hemolysis. Various modifications and constructive steps of the spindle pump were necessary to keep stress on blood components within adequate limits. The actual prototype--tested in three acute experiments and eight experiments with a longer pumping duration (the longest lasting 63 hours)--is described in extenso, and its development is discussed.

Animals↗