Inducible nitric oxide synthase (iNOS) expression may predict distant metastasis in human melanoma

Expression of inducible nitric oxide synthase (iNOS) and its cellular localization was investigated in subcutaneous or lymph node metastases of human melanoma. Immunohistochemistry revealed that iNOS expression was limited to melanoma cells. In samples of patients without distant metastases, the number of iNOS+ tumour cells/total tumour cells was 55% +/- 17% (n = 12) compared with 9% +/- 8% when distant metastases of lung, liver or brain occurred within an observation period of 3 years (n = 10) (P < 0.001). Western blotting confirmed the expression of iNOS protein in select cases. Notably, iNOS is expressed in regional melanoma metastases and its expression is inversely related to the tumour's metastatic potential. Thus, iNOS expression may have predictive value for the development of distant metastases of human melanoma.

Influence of increased c-Myc expression on the growth characteristics of human melanoma

Overexpression of the proto-oncogene c-myc has been associated with neoplastic transformation in a variety of tumors. For human melanoma high c-myc expression has been found in the vertical growth phase and higher positivity reported in metastases than primary tumors. The principle aim of this study was to determine, whether c-Myc expression influences the metastatic behavior of human melanoma in the absence of lymphocyte-mediated immune phenomena. The growth characteristics and tumor biology of two c-myc transfectants of the human melanoma cell line IGR39D, expressing c-Myc 1.7 and three times over baseline and the respective vector control were analyzed both in vitro and in a severe combined immunodeficient mouse model in vivo. Both c-myc transfectants showed increased growth rates, anchorage independent growth and directed cell movement in culture. Subcutaneously implanted IGR39D melanomas highly overexpressing c-Myc spontaneously formed macroscopic metastases (lymph nodes and lung) in severe combined immunodeficient mice in all cases (n = 7 per group), whereas less prominent c-Myc overexpression caused the development of only lung micrometastases. During the time period leading to terminal disease in animals injected with c-myc transfected human melanoma cells, melanoma development was not seen in vector controls. These findings suggest that constitutive high c-Myc expression in human melanoma results in a more aggressive growth behavior both in vitro and in vivo and favors metastasis in severe combined immunodeficient mice by factors unrelated to immune phenomena such as class I human leukocyte antigen downregulation known to be associated with c-Myc expression.

[Chronic liver disease after treatment of malignancies in children]

Chemotherapy, which has greatly improved the prognosis of children with malignant diseases, is potentially hepatotoxic. Furthermore, there is a risk for viral hepatitis acquired by blood products. In this study we looked for hepatotoxicity and for chronic viral hepatitis during and after chemotherapy in 50 unselected children with malignant diseases. 29 children had been treated for leukemia or lymphoma, 19 for solid tumors, 2 for histiocytosis. All patients had been treated before 1991 and had received blood products not screened for hepatitis C-antibodies. In 18 girls and 32 boys aged 12.3 years (range 6.7-24.5 years) hepatitis B- and hepatitis C-serology and liver function tests were measured during a routine check-up 3.6 years (range 0.5-11.8 years) after the last chemotherapy. Liver function tests during chemotherapy were reviewed retrospectively. During chemotherapy 86% of children showed increased ALT and AST levels, 10% had levels above 500 U/l. At follow up 16 children (32%) had pathological liver function tests, especially slightly increased AST and ALT, 13 of these 16 patients had chronic hepatitis C. In contrast only 2 of 34 patients with normal liver function tests had a viral hepatitis (p = 0.001). Patients with elevation of AST and ALT above 100 U/l during chemotherapy had significantly more often a viral hepatitis than those with normal or slightly elevated aminotransferases. Our study shows that hepatocellular damage is a frequent complication following chemotherapy. However this progresses to chronic liver disease very rarely unless the patient acquired a viral hepatitis. The prevalence of chronic hepatitis C was very high in our patients. As screening of blood products for hepatitis C-antibodies is routinely performed since 1991 this problem is likely to have decreased.

Deletions of the region 17p11-13 in advanced melanoma revealed by cytogenetic analysis and fluorescence in situ hybridization

The significance of the p53 tumour-suppressor gene in the oncogenesis of a variety of malignant tumours has been demonstrated over recent years. However, the role of p53 in human malignant melanoma is still unclear. Therefore, we investigated melanoma metastases from 11 patients cytogenetically and with fluorescence in situ hybridization (FISH) after short-term culture, employing a p53 region-specific probe for 17p13.1 and a probe detecting the centromere of chromosome 17. Furthermore, paraffin-embedded tissue samples from nine of these patients were investigated immunohistochemically for expression of the p53 protein. Deletions of the short arm of chromosome 17 were seen in six melanomas in cytogenetic analysis. With FISH, three malignant melanomas had clones with only one p53-allele and an additional four malignant melanomas showed a reduced number of signals at the p53 tumour-suppressor gene locus compared with signals for the centromeric region of chromosome 17. This was confirmed by immunohistochemistry. Our results suggest that the 17p11-13 region is frequently deleted in malignant melanomas and that p53 or other genes located on this band might contribute to the malignant potential of advanced melanoma.

[Ambulatory nursing-care related social work]

From a gerontological point of view, social work which accompanies care processes is absolutely necessary. The social production of care depends crucially on an appropriate attention toward the fitting between informal and formal help systems. Social work can support these fitting processes both on a firm level and on a neutral level. Some specific attributes of social work with elder care-dependant living in their private homes are discussed, such as threatening, difficult or ashaming aspects, as well as the necessity of all involved persons agreeing in the developed help-planning process. Practice research and Social science perspectives are discussed as appropriate reference system for life-world orientated social work with informal caregiving arrangements. Concerning the support of informal caregivers as an important example of ambulant social work with elder people, some dimensions of theoretical and practical professionality are proposed.

Transdermal penetration of diclofenac after multiple epicutaneous administration

OBJECTIVE

To test whether therapeutic diclofenac concentrations are attained in skeletal muscle tissue beneath the application site of an epicutaneously administered diclofenac foam formulation.

METHODS

Diclofenac foam (5%) was administered epicutaneously at the thigh 80 mg/200 cm2 twice daily for a period of 7 days in healthy volunteers (n=12). On Day 8, 2 microdialysis probes were inserted into skeletal muscle tissue beneath the application site and an 80 mg dose was administered epicutaneously. Concentration versus time profiles in plasma and skeletal muscle were followed for 10 hours.

RESULTS

Concentration versus time profiles were obtained for plasma and interstitial muscle fluid in all experiments. Mean Cmax in plasma was 18.75+/-4.97 ng/ml. Corresponding interstitial concentrations in skeletal muscle were significantly higher, 219.68+/-66.36 ng/ml (p=0.01). Plasma concentrations were not correlated to tissue concentrations (r=-0.08).

CONCLUSION

There is significant direct penetration of diclofenac into skeletal muscle following multiple epicutaneous administration. However, the concentration attained in individual subjects is not predictable and may be strongly influenced by individual skin properties.

Technetium-99m-tetrofosmin: a new agent for melanoma imaging?

The aim of our study was to examine whether technetium-99m 1,2-bis[bis(2-ethoxyethyl) phosphino]ethane (tetrofosmin) a lipophilic, cationic tracer which was first developed for myocardial perfusion imaging, could be a new radiopharmaceutical for melanoma imaging. We therefore used two human cell lines, SK-MEL 28 and 5i8 A2 (n = 6, cell concentration 106/ml, incubation at 22 degrees C and 37 degrees C, 50-100 approximately lCi/ml Tc-99m-tetrofosmin, time of incubation 10-180 minutes). The cellular uptake by both cell lines was determined. In contrast to another non- melanoma tumor cell line MCF-7 (a human adenocarcinoma breast cancer) which reached steadystate almost immediately (within 10 minutes), the cellular uptake of SK-MEL-28 increased after 60 minutes and showed a very high uptake (> 10%) after 120 minutes and decreased after 180 minutes (6-8%), while the uptake in 518 A2 cells was about 5% after 90 minutes. Our data show that Tc-99m-tetrofosmin could be a promising agent for melanoma imaging.

Expression of Bcl-2 family members in human melanocytes, in melanoma metastases and in melanoma cell lines

In human melanoma no complete information about the expression of the apoptosis-promoting and apoptosis-inhibiting members of the Bcl-2 family has been available to date. In this study we have investigated by Western blotting the expression pattern of Bcl-2 and its homologues Bax, Bak, Bcl-xL, Bcl-xS, Mcl-1 and Bad in 12 distant lymph node metastases from patients who have been treated by different regimes, in nine newly established cell lines of these metastases, in three cell lines obtained from other sources and in primary melanocytic cell lines from three neonatal and two adult subjects. Taken together, our data suggest that Bax, Bak, Bad, Bcl-xL and Mcl-1 are expressed in addition to Bcl-2 in both normal melanocytes and in cell lines established from melanoma metastases. Regarding the role of Bcl-2 and its homologues, our data suggest that expression of this class of proteins is widespread and qualitatively similar in melanoma cell lines and normal human melanocytes. Although the expression of these proteins might affect growth behaviour and the progression of melanomas, our results are not compatible with the hypothesis that the Bcl-2 homologues investigated play a dominant role in the process of malignant transformation of melanocytes.

bcl-2 antisense therapy chemosensitizes human melanoma in SCID mice

Malignant melanoma is a prime example of cancers that respond poorly to various treatment modalities including chemotherapy. A number of chemotherapeutic agents have been shown recently to act by inducing apoptosis, a type of cell death antagonized by the bcl-2 gene. Human melanoma expresses Bcl-2 in up to 90% of all cases. In the present study we demonstrate that bcl-2 antisense oligonucleotide treatment improves the chemosensitivity of human melanoma grown in severe combined immunodeficient (SCID) mice. Our findings suggest that reduction of Bcl-2 in melanoma, and possibly also in a variety of other tumors, may be a novel and rational approach to improve chemosensitivity and treatment outcome.

Bcl-2 prolongs cell survival after Bax-induced release of cytochrome c

Following exposure of cells to stimuli that trigger programmed cell death (apoptosis), cytochrome c is rapidly released from mitochondria into the cytoplasm where it activates proteolytic molecules known as caspases that specifically cleave the amino-acid sequence DEVD and are crucial for the execution of apoptosis. The protein Bcl-2 interferes with this activation of caspases by preventing the release of cytochrome c. Here we study these molecular interactions during apoptosis induced by the protein Bax, a pro-apoptotic homologue of Bcl-2. We show that in cells transiently transfected with bax, Bax localizes to mitochondria and induces the release of cytochrome c, activation of caspase-3, membrane blebbing, nuclear fragmentation, and cell death. Caspase inhibitors do not affect Bax-induced cytochrome c release but block caspase-3 activation and nuclear fragmentation. Unexpectedly, Bcl-2 also fails to prevent Bax-induced cytochrome c release, although it co-localizes with Bax to mitochondria. Cells overexpressing both Bcl-2 and Bax show no signs of caspase activation and survive with significant amounts of cytochrome c in the cytoplasm. These findings indicate that Bcl-2 can interfere with Bax killing downstream of and independently of cytochrome c release.

Role of an acidic compartment in tumor-necrosis-factor-alpha-induced production of ceramide, activation of caspase-3 and apoptosis

Tumor necrosis factor-alpha (TNF-alpha) apoptosis by recruiting a complex of cytosolic proteins at its plasma membrane receptor. Among them is caspase-8, an interleukin-1beta-converting enzyme (ICE)-like protease that initiates an amplified protease cascade to activate the cell-death machinery. The latter comprises at least caspase-3 and caspase-7, which execute cell death by cleaving numerous protein substrates, including poly(ADP-ribose) polymerase. In addition, TNF-alpha stimulates the production of ceramide, which also activates the death machinery. Whether the signaling pathways elicited by caspase-8 and ceramide proceed independently or intersect at a specific subcellular site is unknown. Using the lysosomotropic agent NH4Cl and the vesicularization inhibitor brefeldin A, we show here the convergence of TNF-alpha-induced death signaling on an acidic, subcellular compartment reminiscent of lysosomes. This compartment generates at least two signaling pathways that account for the caspase-3 activation and apoptosis induced by TNF-alpha, one involving ceramide and caspase-unrelated adapter molecules and another involving yet unknown lysosomal mediators. The apoptosis inhibitor Bcl-2 specifically acts on the ceramide-activated pathway to block caspase-3 activation and apoptosis. The latter result explains why Bcl-2 only partially blocks TNF-alpha-induced apoptosis.

Increased risk of catheter colonization and catheter-related infections in severe immunocompromized patients with multiple myeloma undergoing high-dose glucocorticoid treatment

Catheter-related infections (CRI) are an important problem in medicine because of major consequences for treatment, prolongation of hospitalization and increasing therapy costs. Malignancies, immunodeficiency, severe burns and malnutrition compromise host defense. Studies to quantify the increased risk of CRI in immunocompromised patients are required. We analyzed the influence of immunoglobulin deficiency and high-dose glucocorticoid treatment in patients with multiple myeloma with regard to catheter colonization and CRI. In patients with multiple myeloma, central venous catheters (CVC) were significantly more frequently colonized (> 15 CFU) as compared to patients with other malignancies undergoing chemotherapy. We found a tendency towards a higher CRI rate in the myeloma patient group. Interestingly, despite of the significantly higher incidence of catheter colonization and a tendency towards higher CRI rates in severely immunocompromised patients, the incidence of signs of local (redness of the entry site) and systemic (fever) host reactions is reduced in myeloma patients. To decrease the CRI rate in myeloma patients during chemotherapy which includes high-dose glucocorticoids, we use antibacterial (silver-coated) catheters.

A silicone ventricular catheter coated with a combination of rifampin and trimethoprim for the prevention of catheter-related infections

So-called antiinfective catheters which are generated by incorporation of antimicrobial substances into polymers appear to be effectful devices in the prevention of catheter related infections. Such devices mainly act by prevention of bacterial colonization of the catheter surface rather than by inhibition of adherence. In a preceding study, we developed a rifampin-containing silicone catheter for the prevention of ventricular shunt infection. In the present study, this work was continued with a combination of antimicrobials incorporated in silicone ventricular catheters to reduce the risk of rifampin resistance and to expand the antimicrobial spectrum. We found that the drug release kinetics could be greatly influenced by the incorporation conditions. It was possible to incorporate an optimal antibiotic combination of rifampin and trimethoprim into the polymer resulting in defined release rates and a defined total release. A catheter loaded with this combination showed an excellent reduction of the colonization with Staphylococcus aureus (99.97% reduction within 3 hours) under in-vitro conditions.

In vitro efficacy of a hydrophilic central venous catheter loaded with silver to prevent microbial colonization

A method was developed to load the surface of a central venous catheter with silver to prevent bacterial colonization. Silver confers a broad antimicrobial activity with a relatively low risk of resistance. Catheters were incubated with a silver nitrate solution in different concentrations. The solvent, incubation temperature and incubation period were varied to examine the influence on the catheter loading. With increasing incubation temperature, time and concentration of silver nitrate, higher rates of silver elution were observed by atomic absorption spectroscopy. Furthermore, by using ethanol-water as a solvent instead of pure water, the amount of silver bound to the catheter surface was enhanced. The release of silver from the catheter surface is mainly controlled by first order kinetics. Antimicrobial efficacy of the modified catheter, in comparison to unloaded catheters, was tested in a stationary and a dynamic model with different microorganisms. Adherence experiments with Candida albicans showed almost complete inhibition of growth during a period of 72 hours, including initial adherence. While initial adherence of bacteria could not be prevented, these experiments showed an excellent reduction of bacterial colonization. In a perfusion model, adhesion of E. coli could be reduced for at least seven days. Further studies are planned to examine prolonged antimicrobial effects.

Melanoma progression-associated glycoprotein MUC18/MCAM mediates homotypic cell adhesion through interaction with a heterophilic ligand

MUC18/MCAM is a cell-surface glycoprotein that is strongly expressed on advanced human melanomas. Transfection of 3 MCAM-negative melanoma cell lines with MCAM cDNA led to cell-surface expression and to a MCAM-dependent homotypic adhesion. This adhesion was independent of divalent cations and was inhibited at 4 degrees C. Mixed aggregation assays with MCAM-expressing and non-expressing cells revealed that MCAM can function as a heterophilic cell adhesion molecule interacting with a non-MCAM ligand. Although MCAM contains a potential glycosaminoglycan-binding site, cell-surface glycosaminoglycans do not appear to be involved in the heterophilic adhesion observed here since these molecules were not able to influence the adhesion. Using a functional adhesion assay, 4/4 melanoma cell lines examined were found to express an MCAM ligand. In contrast, no evidence for an MCAM ligand was found on the 2 carcinoma or 2 hematopoietic cell lines examined. Stable transfection of an MCAM ligand-negative colorectal cell line resulted in MCAM surface expression but not in homotypic adhesion, indicating that homophilic MCAM-MCAM adhesive interactions may not occur. Our results suggest that MCAM expression by melanoma cells is associated with increased homotypic adhesion, an event that may support tumor cell survival and growth in vivo.

In vivo drug-response measurements in target tissues by microdialysis

To study the suitability of the microdialysis technique for the measurement of target tissue pharmacodynamics in humans, the model compounds theophylline, milrinone, and compound 48/80 were administered locally by means of reversed microdialysis to the interstitial space of skeletal muscle or skin in 24 healthy volunteers. Simultaneously, interstitial concentrations of cyclic adenosine monophosphate (cAMP; as an indicator of phosphodiesterase activity) were measured in skeletal muscle, and interstitial concentrations of histamine (as an indicator of mast cell release) were measured in skin. In muscle, reversed microdialysis with milrinone led to a dose-dependent increase in interstitial cAMP concentrations (n = 8), whereas no significant effect on cAMP was observed for theophylline versus placebo (1.63 +/- 0.53 nmol/L; n = 6), even at local concentrations exceeding those attained after therapeutic doses. In skin, reversed microdialysis with compound 48/80 increased interstitial histamine concentration dose dependently versus placebo (5.99 +/- 2.74 nmol/L; n = 10). From our experiments in human skeletal muscle and skin, we concluded that microdialysis was a suitable technique for the characterization of in vivo drug response at the relevant target site. Extension of these measurements to several other human tissues is readily feasible.

5-fluorouracil kinetics in the interstitial tumor space: clinical response in breast cancer patients

Several anticancer drugs fail to exhibit sufficient activity against solid tumors in vivo despite effective inhibition of tumor cell growth in vitro. This may be due to impaired drug transfer from plasma into solid tumors. The present study, therefore, aimed at measuring interstitial tumor 5-fluorouracil (5-FU) pharmacokinetics and 5-FU transfer rates from plasma into the tumor interstitium in breast cancer patients. Microdialysis probes were inserted into the primary tumor and the periumbilical s.c. adipose layer of 10 breast cancer patients (8 females and 2 males) scheduled to receive neoadjuvant chemotherapy due to locally advanced breast cancer. Thereafter, patients received 5-FU (600 mg/m2, i.v). 5-FU kinetics were followed in plasma and tumor and s.c. interstitial fluid. Mean interstitial 5-FU load, expressed as area under curve (AUC), in breast tumors was 61 +/- 11% (means +/- SE) of the mean plasma 5-FU load. 5-FU displayed similar kinetics in the interstitial space of s.c. adipose tissue and tumor tissue. A high interstitial tumor AUC was associated with increased tumor response. There was no association with tumor response for s.c. or plasma AUC of 5-FU. Measurement of interstitial drug concentrations in breast tumors by in vivo microdialysis may predict response to chemotherapy. This information may explain drug resistance in some patients and help to optimize dosing and administration schedules. In the future, selection of novel cytotoxic compounds with favorable tumor penetration characteristics may become possible.

Activated N-ras contributes to the chemoresistance of human melanoma in severe combined immunodeficiency (SCID) mice by blocking apoptosis

Activation of the N-ras gene by point mutations occurs in about 15 % of all human melanomas. Using recently established melanoma severe combined immunodeficiency-human mouse xenotransplantation models, here we further investigate the biological significance of these mutations. We demonstrate that activated N-ras significantly contributes to the chemoresistance of human melanoma both in vitro and in vivo by blocking apoptosis. Overexpression of wild-type N-ras had no such effects. With antisense oligonucleotides and farnesyltransferase inhibitors, tools capable of blocking Ras function on the therapeutic horizon, our observation that activated N-ras is not a bystander but a factor worth targeting to improve therapeutic outcome in melanoma gains additional importance.

Characterization of peripheral-compartment kinetics of antibiotics by in vivo microdialysis in humans

The calculation of pharmacokinetic/pharmacodynamic surrogates from concentrations in serum has been shown to yield important information for the evaluation of antibiotic regimens. Calculations based on concentrations in serum, however, may not necessarily be appropriate for peripheral-compartment infections. The aim of the present study was to apply the microdialysis technique for the study of the peripheral-compartment pharmacokinetics of select antibiotics in humans. Microdialysis probes were inserted into the skeletal muscle and adipose tissue of healthy volunteers and into inflamed and noninflamed dermis of patients with cellulitis. Thereafter, volunteers received either cefodizime (2,000 mg as an intravenous bolus; n = 6), cefpirome (2,000 mg as an intravenous bolus; n = 6), fleroxacin (400 mg orally n = 6), or dirithromycin (250 mg orally; n = 4); the patients received phenoxymethylpenicillin (4.5 x 10(6) U orally; n = 3). Complete concentration-versus-time profiles for serum and tissues could be obtained for all compounds. Major pharmacokinetic parameters (elimination half-life, peak concentration in serum, time to peak concentration, area under the concentration-time curve [AUC], and AUC/MIC ratio) were calculated for tissues. For cefodizime and cefpirome, the AUCtissue/AUCserum ratios were 0.12 to 0.35 and 1.20 to 1.79, respectively. The AUCtissue/AUCserum ratios were 0.34 to 0.38 for fleroxacin and 0.42 to 0.49 for dirithromycin. There was no visible difference in the time course of phenoxymethylpenicillin in inflamed and noninflamed dermis. We demonstrated, by means of microdialysis, that the concept of pharmacokinetic/pharmacodynamic surrogate markers for evaluation of antibiotic regimens originally developed for serum pharmacokinetics can be extended to peripheral-tissue pharmacokinetics. This novel information may be useful for the rational development of dosage schedules and may improve predictions regarding therapeutic outcome.

N-ras oncogene expression changes the growth characteristics of human melanoma in two independent SCID-hu mouse models

Fifteen percent of all human melanomas carry mutations in ras genes, the majority of which are located in codon 61 of the N-ras gene. However, the biological significance of these mutations is as yet unknown. In this study, we investigated the influence of N-ras oncogene products mutated in codon 61 on the growth characteristics of human melanoma in vivo by establishing 2 SCID-hu mouse xenotransplantation models. Tumors grown in SCID mice injected with human melanoma carrying activated N-ras genes were significantly larger (p < 0.004) than tumors grown in animals injected with the appropriate control transfectants. Additionally, tumors with N-ras point mutations clearly showed a more pleomorphic phenotype than the control groups. Our results, obtained in 2 independent SCID-hu xenotransplantation models, suggest that mutated N-ras oncogene expression may be an important factor influencing growth characteristics of human melanoma without altering metastatic potential. These novel in vivo model systems provide a tool for further study of the biology of mutated ras in melanoma and should also prove useful for testing new and improved treatment strategies for human melanoma carrying mutated ras genes.

Influence of induction of HSP70 on the cytotoxicity of oxazaphosphorine compounds and cisplatin

Induction of HSP70 and thermotolerance may also decrease the cytotoxicity of cytostatic agents or their combination with hyperthermia in clinically used thermochemotherapy. HSP70 and thermotolerance were induced by hyperthermia (42 degrees C, 1 h) in two human tumor cell lines in vitro and in vivo. The influence of thermotolerance on the cytotoxicity of CDDP and the oxazaphosphorine compounds Mafo and Ifo and their combination with hyperthermia (42 degrees C or 43 degrees C, 1 h) were studied. The results show that neither thermotolerance nor HSP70 affects the tumor cell sensitivity to CDDP or oxazaphosphorine compounds. However, the additive effect of hyperthermia and CDDP was found to be attenuated in thermotolerant cells. The cytotoxicity of oxazaphosphorine compounds combined with hyperthermia was not altered after preheating, suggesting a different mechanism may be responsible for the drug-hyperthermia interaction of CDDP and oxazaphosphorine compounds. There were no differences between in vitro and in vivo results suggesting mechanisms at the cellular level being responsible for the influence of thermotolerance on drug- and drug-hyperthermia action.

In-vitro activity of penicillin G plus sulbactam in comparison with other beta-lactamase inhibitor combinations and oxacillin against staphylococci

The in-vitro activity of penicillin G in combination with the beta-lactamase inhibitor, sulbactam, against penicillin-sensitive S. aureus (n = 10) and penicillin-resistant, methicillin-sensitive S. aureus (n = 69) and S. epidermidis (n = 20) was tested in comparison with ampicillin/sulbactam, amoxicillin/clavulanic acid, piperacillin/tazobactam and oxacillin. The combination of penicillin G plus sulbactam was found to lead to MIC values for beta-lactamase producing staphylococci comparable to those for penicillin-sensitive staphylococci, with MIC90 values between < or = 0,03 mg/L and 0.06 mg/L.

[Nosocomial infections in head and neck surgery. 2. A prospective study]

Nosocomial infections are defined as infections that occur during hospitalization but were not present at admission. Nosocomial infections have been found to occur in 6% of all hospitalizations and are present mainly in intensive care units and surgical wards. These infections extend the time of hospitalization and therefore increase the cost of care. Between July and December 1993, all nosocomial infections occurring in 304 patients of the surgical ward of the University ENT Department, Cologne, were recorded prospectively. These were classified into wound, implant, urinary tract, respiratory, skin or mucosal infections, nosocomial bacteremias and gastrointestinal infections. The overall prevalence of nosocomial infections was 15.4%. Of these, 9.2% were postoperative wound infections, 2.6% respiratory infections, and 2.3% infections of the skin and mucosa. The incidence of urinary tract infections was 0.7%, while bacteremias occurred in 0.3%. No implant or gastrointestinal infections occurred. Microbial analysis demonstrated 9 gram-positive and 15 gram-negative bacterial and 8 candidal infections. Nineteen cultures were negative. Among the bacteria cultured three were methicillin-resistant. The time of hospitalization was extended from a normal average of 9.52 days to 25.7 days. The distinct risk of a nosocomial infection in the treatment of hospitalized patients requires and accurate documentation of all acquired infections. Determination of the source of infection, the method of spread and microbial analysis including the spectrum of organism resistance is necessary in order to decrease the infection rate and to prevent establishment of a nosocomial infection. These requirements at the least are an important part of quality control in the surgical disciplines.