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Biomedical subjects

J Dankert

Publications and source records attributed to J Dankert.

At least 235 records · Page 13Linked to original sources

Recurrent acute leg cellulitis in patients after radical vulvectomy.

Recurrent acute leg cellulitis (ALC) known to occur in patients with impaired venous or lymphatic circulation was studied in 126 patients after radical vulvectomy with lymphadenectomy through the years 1973 to 1985. Among these patients surveyed for a total period of 6153 patient months, 33 (26%) experienced 75 episodes of ALC. Recurrent attacks were frequently observed. Although antimicrobial treatment was often started, clinical signs resolved also in 9 patients without antimicrobial treatment. To prevent recurrencies penicillin prophylaxis was given to 23 patients. Only 1 of them had once a mild attack of ALC, whereas recurrent attacks occurred frequently in those patients not receiving penicillin prophylaxis. Although penicillin prophylaxis was successful in preventing the recurrence of ALC the risk-benefit ratio of this approach has not been ascertained. The etiology and pathogenesis of recurrent ALC is discussed. Analysis of a number of assumed risk factors for ALC showed that the frequency of ALC was significantly higher in patients colonized with beta-hemolytic streptococci, mainly group B, than in patients not colonized with these microorganisms just prior to surgery. This suggests that non-group A beta-hemolytic streptococci are involved in the onset of ALC in patients after radical vulvectomy. However, portals of entry for microorganisms were not apparent in any of our patients.

Acute Disease↗

A comparison of the effects of preoperative whole-body bathing with detergent alone and with detergent containing chlorhexidine gluconate on the frequency of wound infections after clean surgery. The European Working Party on Control of Hospital Infections.

In a prospective, randomized, double-blind, placebo-controlled study involving 27 surgical units in six European countries, the effect of preoperative whole-body bathing on two occasions with a detergent containing chlorhexidine (CHX+) on the incidence of wound infection in elective, clean surgery was compared with two bathings with a detergent without chlorhexidine (CHX-). In the CHX+ group 2.62% of 1413 patients and in the CHX- group 2.36% of 1400 patients subsequently became infected. The infection rate in the CHX+ group was 1.11 times that in the CHX- group with 95% confidence limits ranging between 0.69 and 1.82. Consequently, bathing patients twice preoperatively with chlorhexidine-detergent did not reduce the incidence of infection of clean wounds.

Adolescent↗

Prophylactic antibiotic treatment prevents infection after cardiopulmonary bypass: a study in dogs.

The effect of two prophylactic antibiotic regimens during cardiopulmonary bypass (CPB) was investigated in dogs. Airborne contamination was determined by spraying two different bacterial strains (Staphylococcus aureus and Serratia marcescens) into the air of the operating room. Dogs were operated on and underwent CPB with a bubble oxygenator. Pericardial suction, either conventional (blood-air) or selective (only blood), was used. Particularly in the first situation, an impaired humoral host defense is induced. In dogs given the regimen consisting of penicillin G (benzylpenicillin), gentamicin sulfate, and flucloxacillin, the number of contaminated sites for both bacteria was reduced (p less than .01) compared with those given cefuroxime. The effectiveness of the combined antibiotic regimen could be ascribed to increased serum bactericidal activity and polymorphonuclear leukocyte (PMN) killing capacity. Cefuroxime enhanced the PMN respiratory burst. As a result, two weeks postoperatively the rate of infection was small in both groups. We conclude that prior to CPB, antibiotics should be administered prophylactically to overcome a period of impaired humoral host defense during CPB.

Animals↗

Bubble oxygenation and cardiotomy suction impair the host defense during cardiopulmonary bypass: a study in dogs.

Decreased complement levels and impairment of polymorphonuclear leukocyte function increase the risk of infection during cardiopulmonary bypass (CPB). The effects of different types of oxygenator and of blood suction on this natural humoral and cellular host defense mechanism were investigated in dogs undergoing CPB during sham open-heart operations. Airborne contamination of the wound area and the CPB circuit was performed by aerosolizing Staphylococcus aureus. A membrane oxygenator in the CPB circuit maintained a normal host defense mechanism. The use of cardiotomy suction during CPB with this type of oxygenator affected the host defense to some extent. The use of a bubble oxygenator in the CPB circuit together with cardiotomy suction seriously impaired the host defense. Postoperatively bacteremia developed in no dogs in the membrane oxygenator group, whereas 8 of 15 dogs in the bubble oxygenator group had a positive blood culture for the indicator microorganism. We conclude that the use of a membrane oxygenator is helpful to maintain the host defense. Attention has to be paid to reduce the deleterious effects of cardiotomy suction.

Animals↗

Recurrent acute leg cellulitis after hysterectomy with pelvic lymphadenectomy.

Recurrent acute leg cellulitis known to occur in patients with impaired venous or lymphatic circulation was surveyed prospectively in 270 patients after radical hysterectomy with pelvic lymphadenectomy and in 66 patients after hysterectomy with pelvic lymphadenectomy from 1977 to 1985. Among them, six (2%) and three (4%) patients experienced a total of 17 episodes of acute leg cellulitis, respectively. Analysis showed that postoperative percutaneous radiation therapy of the pelvic area was a highly significant risk factor. Penicillin prophylaxis is recommended for patients experiencing recurrent attacks.

Acute Disease↗

Adhesion of coagulase-negative staphylococci to methacrylate polymers and copolymers.

Adhesion of coagulase-negative staphylococci (CNS) was studied onto a homologous series of methacrylate polymers and copolymers. The materials varied in wettability (contact angles) and were either positively or negatively charged (zeta-potential). Bacterial adhesion experiments performed in a parallel-plate perfusion system showed that positively charged TMAEMA-Cl copolymers significantly promoted the adhesion of CNS as compared with all other methacrylate (co)polymers tested. The bacterial adhesion rates onto the positively charged surfaces are diffusion-controlled, whereas those onto the surfaces with a negative zeta-potential are more surface-reaction-controlled due to the presence of a potential energy barrier. The bacterial adhesion rates onto various poly (alkyl methacrylates) were similar. The number of adhering bacteria onto the negatively charged MMA/MAA copolymer did not differ from that onto pMMA, indicating that sufficient sites on the copolymer surface with the same potential energy barrier as that on pMMA, were available for adhesion. Decreasing rates of adhesion of CNS were observed onto MMA/HEMA copolymers with increasing HEMA content coinciding with increasing hydrophilicity. Low plateau values for the bacterial adhesion were observed on 50MMA/50HEMA, pHEMA, and 85HEMA/15MAA, indicating that the adhesion onto these materials was reversible. Four CNS strains with different surface characteristics all showed higher numbers of adhering bacteria onto 85MMA/15TMAEMA-Cl than onto 85MMA/15MAA and pMMA.

Binding Sites↗

Airborne contamination during cardiopulmonary bypass: the role of cardiotomy suction.

Airborne contamination of the wound area and the cardiopulmonary bypass circuit during sham open-heart operations on dogs was studied. The air of the operating room (OR) was contaminated with two typeable bacterial strains. It was found that the number of wounds, blood specimens, oxygenators, and cardiotomy reservoirs contaminated with Staphylococcus aureus was related to the number of S. aureus present in the air of the OR, but that contamination with Serratia marcescens was related to the type of suction used. This form of contamination was considerably higher when air was aspirated together with blood into the suction line (p less than 0.05). The oxygenator and cardiotomy reservoir were contaminated mainly by aspirating wound fluid from the airborne-contaminated wound area. The low number of sample sites positive for S. marcescens may be due to a better preserved host defense mechanism if only wound fluid is sucked. A rather high incidence of postoperative infections occurred even in dogs operated on in an OR with a low level of airborne contamination.

Air Microbiology↗

Cell surface characteristics of coagulase-negative staphylococci and their adherence to fluorinated poly(ethylenepropylene).

The ability of 21 nonencapsulated and 15 encapsulated coagulase-negative staphylococci (CNS) to adhere to xylene in xylene-water emulsions and to fluorinated poly(ethylenepropylene) (FEP) films revealed remarkable differences. Nonencapsulated CNS strains adhered well to FEP, whereas their adherence to xylene ranged widely. Encapsulated strains with low adherence to xylene showed slight adherence to FEP. Encapsulated strains which adhered well to xylene ranged widely in their adherence to FEP. It was concluded that results obtained from the xylene adherence test were not predictive of the adherence of CNS to the hydrophobic FEP surface. The number of nonwashed, slime-producing CNS strains adhering to FEP was similar to that of washed bacteria of the same strains. Bacterial adherence to FEP was decreased when FEP films were exposed to a solution containing extracellular products (EP) obtained from a slime-producing CNS strain. Bacterial adherence to xylene also decreased when the bacterial suspensions contained EP. Apparently, initial adherence of CNS to FEP and xylene is hampered by EP. Nonencapsulated and encapsulated CNS pretreated with proteolytic enzymes failed to adhere to xylene and FEP, indicating that intact surface proteins or constituents associated with surface proteins mediated their adherence to xylene and FEP. Freeze-etch replicas of a CNS strain adhering to FEP showed a smooth, flattened area on the bacterial surface at the contact site of the bacteria with the FEP, indicating that an external layer was present at the bacterial surface.

Adhesiveness↗

Adhesion of Staphylococcus epidermidis and Staphylococcus saprophyticus to a hydrophobic biomaterial.

The relative surface charge and hydrophobicity of 16 strains of Staphylococcus epidermidis showed large variations. For this species no relationship between the two surface parameters was found. A highly negative surface charge was observed in all seven encapsulated strains (one S. epidermidis and six Staphylococcus saprophyticus strains). The adhesion of the staphylococci to fluorinated polyethylene-propylene films was not related to the relative surface charge and the hydrophobicity of the bacteria. On films pre-exposed to human plasma, the bacterial adhesion was substantially reduced. Mechanisms involved in the adhesion of coagulase-negative staphylococci to this biomaterial are discussed.

Adhesiveness↗

Immune response to two different hepatitis B vaccines in haemodialysis patients: a 2-year follow-up.

Formalin-inactivated hepatitis B vaccine was given at 0, 1 and 6 months to 22 medical staff members and to 37 haemodialysis patients. After vaccination with 20 micrograms surface antigen (HBsAg), seroconversion occurred in 95% of the staff members. Following immunisation with a double dose, only 74% of the haemodialysis patients developed antibodies against HBsAg (anti-HBs). Anti-HBs levels were lower in the patient group and 6 responders (23%) became anti-HBs-negative within 2 years. 40 other haemodialysis patients were immunised at monthly intervals with either three doses of 3 micrograms or three doses of 27 micrograms heat-inactivated hepatitis B vaccine. Seroconversion was achieved in 60% of the patients in the 3-micrograms group and in 95% of the patients in the 27-micrograms group. Anti-HBs levels increased significantly when the high dose was used. Although the study design does not allow a definite conclusion, it appears that the immunogenicity per microgram HBsAg is higher for the heat-inactivated vaccine than for the formalin-inactivated vaccine. The findings further indicate that decreased immune response to hepatitis B vaccination in haemodialysis patients can be improved by increasing the dose of the vaccine. A booster injection should be considered in these patients within 2 years after the first vaccination.

Adult↗

Early transient accumulation of methotrexate in the cerebrospinal fluid of rabbits after treatment with methotrexate and roentgen rays.

Concomitant application of intrathecal methotrexate (MTX) and cranial irradiation has been described as being able to cause brain abnormalities in patients with leukemia. In the investigation presented, rabbits were treated once weekly for 6 weeks with intraventricular MTX and irradiation. Cerebrospinal fluid (CSF) sampled at various time points after each treatment contained for the samples obtained 4 hours after treatment increasing amounts of MTX. This indicated a retardation in MTX clearance from the CSF. Such a retardation might contribute to the generation of brain abnormalities, although no data have as yet been obtained to prove this suggestion.

Animals↗

Bacteraemia in surgical patients with intravenous devices: a European multicentre incidence study. The European Working Party on Control of Hospital Infections.

A survey of the incidence of bacteraemia and the use of intravenous (IV) devices among 10,616 surgical patients was performed in 42 hospitals in eight countries. It was found that 63 per cent of the patients surveyed had an IV device inserted at some time during their hospital stay, with national variations between 40 and 99 per cent. The incidence of device-related thrombophlebitis was 10.3 per cent, with national variations between 7.8 and 28.4. Among the surgical patients not given IV therapy, 1.5/1000 had a bacteraemia, 0.5/1000 of them hospital-acquired. The corresponding figures for patients with a peripheral but no central IV device were 6.9 and 3.7, and for patients with a central venous catheter (CVC) 59.0 and 44.8, respectively. Even though there was a strong correlation between the incidence of bacteraemia and certain diagnoses there was also an independent correlation between it and CVCs or peripheral IV lines. No correlation was demonstrated between the number of catheter days per site for patients with a peripheral IV device, and hospital-acquired bacteraemia. This may be due to the low mean number of catheter days per site that was observed. There was a large and not easily explained national variation in the incidence of bacteraemia in patients with CVCs of between 16 and 108/1000.

Catheterization↗

Penicillin prophylaxis in children with cardiac disease: postextraction bacteremia and penicillin-resistant strains of viridans streptococci.

The incidence of postextraction bacteremia in 82 children with dental foci and cardiac disease given parenteral penicillin prophylaxis was assessed 5 min after extraction. Penicillin concentrations were determined in blood samples obtained at the same time. Before extraction, cultures were taken from the gingival sulcus. Postextraction bacteremia occurred in 21% of the patients and was due to penicillin-sensitive microorganisms in 10 and to both penicillin-sensitive and penicillin-resistant microorganisms in seven children. In three of these children penicillin-resistant viridans streptococcal strains were isolated. Penicillin-resistant viridans streptococci were present in the gingival sulcus flora of 39% of the children, but a relationship between the presence of such strains in the gingival sulcus and the occurrence of postextraction bacteremia could not be demonstrated. There was no difference in the serum penicillin concentrations found in children with bacteremia due to penicillin-sensitive or penicillin-resistant microorganisms, or between the concentrations in children with and without bacteremia.

Adolescent↗

Significance of penicillin tolerance in vivo: prevention of experimental Streptococcus sanguis endocarditis.

To determine whether in-vitro tolerance to penicillin among viridans streptococci influences the efficacy of penicillin in vivo, we studied four strains of dextran-producing. Streptococcus sanguis serotype II. All four strains were inhibited in vitro by 0.1 mg/l penicillin or less; one was not-tolerant, one intermediate, and two were tolerant to the lethal action of penicillin. The combination of penicillin and streptomycin killed all strains completely within 24 h in vitro. Sera from rabbits injected with penicillin were inhibitory for all strains, but were bactericidal only for the non-tolerant strain. The incidence of endocarditis in untreated rabbits with left heart catheters was 100% after inoculation of each of the four strains. Despite attempted prophylaxis with procaine penicillin G, endocarditis developed in 44 of 70 rabbits (63%) injected with the tolerant strains, contrasting with 2 of 22 (9%) for the non-tolerant strain (P=0.0001). The probability that penicillin would fail to prevent endocarditis was directly related to its minimal bactericidal concentration for each strain (r=0.95). In contrast, the combination of penicillin plus streptomycin always prevented endocarditis. We conclude that penicillin tolerance can be a crucial determinant of the response of viridans streptococci to penicillin in vivo.

Animals↗

Adhesion of coagulase-negative staphylococci to biomaterials.

The adhesion of two Staphylococcus epidermidis strains and one Staphylococcus saprophyticus strain on to poly(tetrafluorethylene-co-hexafluorpropylene) (FEP)-fluorocarbon and cellulose acetate was studied in vitro. Both S. epidermidis strains showed a more hydrophobic character than the encapsulated S. saprophyticus as determined by the bacterial affinity towards xylene. Staphylococcus epidermidis showed a significantly higher adhesion on to the hydrophobic FEP than S. saprophyticus. The adhesion of staphylococci on to the more hydrophilic cellulose acetate was always low. Treatment of S. epidermidis with pepsin or extraction with aqueous phenol yielded cells with a decreased hydrophobicity, which resulted in a decreased adhesion on to FEP. Cells with a decreased hydrophobicity showed a lower rate of reaggregation in suspension. The hydrophobicity and the adhesion on the FEP of S. epidermidis were not affected by exposure to a subminimal inhibitory concentration of penicillin. The strong interaction between S. epidermidis and FEP, which appeared not to be influenced by the age or the metabolic stage of the bacteria, is mainly caused by hydrophobic bonding.

Adhesiveness↗