Fluorothiazinon, a small-molecular inhibitor of T3SS, suppresses salmonella oral infection in mice

Therapeutic strategies that target bacterial virulence have received considerable attention. The type III secretion system (T3SS) is important for bacterial virulence and represents an attractive therapeutic target. Recently, we developed a new small-molecule inhibitor belonging to a class 2,4-disubstituted-4H-[1,3,4]-thiadiazine-5-ones, Fluorothiazinon (FT-previously called CL-55). FT effectively suppressed T3SS of Chlamydia spp., Pseudomonas aeruginosa, and Salmonella without affecting bacterial growth in vitro. FT was previously characterized by low toxicity, stability, and therapeutic efficacy in animal models. Salmonella T3SS inhibition by FT was studied using in vitro assays for effector proteins detection and estimation of salmonella replication in peritoneal macrophages. The antibacterial effect of FT in vivo was investigated in murine models of salmonella chronic systemic and acute infection. Oral administration of the virulent strain of Salmonella enterica serovar Typhimurium to mice-induced chronic systemic infection with the pathogen persistence in different lymphoid organs such as spleens, Peyer's plaques, and mesenteric lymph nodes. We found that FT suppressed orally induced salmonella infection both with therapeutic and prophylactic administration. Treatment by FT at a dose of 50 mg/kg for 4 days starting from day 7 post-infection (therapy) as well as for 4 days before infection (prevention) led to practically complete eradication of salmonella in mice. FT shows a strong potential for antibacterial therapy and could be used as a substance in the design of antibacterial drugs for pharmaceutical intervention including therapy of antibiotic-resistant infections.

Taurolidine lock solution for catheter-related bloodstream infections in pediatric patients: A meta-analysis

Infection is one of the most commonly described complications, and a major cause of morbidity and mortality in pediatric patients treated using central venous catheters (CVCs). Taurolidine lock solutions have been used to decrease catheter-related bloodstream infections (CRBSIs) in both adult and pediatric patients. The purpose of this study was to systematically search the literature and conduct a meta-analysis to determine the efficacy of taurolidine in reducing CRBSI in children. We conducted an electronic search of the PubMed, EMBASE, Cochrane Library, TRIP Database, CINAHL, and Google Scholar databases for articles published up to 1^st November 2019. Eligible studies included randomized controlled trials (RCTs) comparing the effects of taurolidine with control for preventing CRBSI in pediatric patients. Four studies were included. Our results indicated a statistical significant reduction in the total number of CRBSI with taurolidine as compared to control (RR: 0.23; 95% CI:0.13, 0.40; I² = 0%; P<0.00001). The pooled analysis also indicated a statistical significant reduction in the incidence of CRBSI (defined as the number of CRBSI events/1000 catheter days) in the taurolidine group (MD: -1.12; 95% CI:-1.54, -0.71; I² = 1%; P<0.00001). The number of catheters removed due to infection or suspected infection was not significantly different between the two groups (RR: 0.68; 95% CI:0.22, 2.10; I² = 56%; P = 0.50) (Fig 5). The quality of the included studies was not high. The use of taurolidine as a catheter locking solution may significantly reduce CRBSI in pediatric patients. However, the quality of current evidence is not high and further high-quality large scale RCTs are needed to corroborate our results.

In-vitro effects of taurolidine alone and in combination with mitoxantrone and/or piroxicam on canine transitional cell carcinoma

The objective of this in-vitro study was to evaluate taurolidine as a therapy for transitional cell carcinomas in canine patients. Transitional cell carcinoma (TCC) is the most common cancer of the urinary bladder in dogs and accounts for approximately 2% of reported malignancies in this species. There is no cure for this neoplasm and most dogs are lost from complications associated with progression of the local disease. Taurolidine has been shown to have anti-tumor and antiangiogenic effects against a variety of neoplasms in human and animal models. Four canine TCC cell lines were treated with various concentrations of taurolidine, mitoxantrone, and piroxicam alone. In addition, combinations of taurolidine/mitoxantrone, taurolidine/piroxicam, mitoxantrone/piroxicam, and taurolidine/mitoxantrone/piroxicam were assessed. Susceptibility of the TCC cell lines was based on a 72-hour growth inhibition assay using resazurin with absorbance measured at λ530/590. The ability of taurolidine to induce apoptosis was evaluated on 2 of the cell lines with an Annexin-V/propidium iodide assay. All cell lines were susceptible to treatment with taurolidine, mitoxantrone, and piroxicam alone. The results of the combination therapies of the 3 drugs were dependent on cell line and concentration and revealed no change in cell growth inhibition, a subadditive relationship, or a synergistic relationship. Taurolidine induced apoptosis in a concentration- and time-dependent fashion. Taurolidine alone showed significant effects on cell viability in vitro in canine TCC cell lines and these effects can be potentially enhanced with the addition of mitoxantrone and/or piroxicam.

Antimicrobial Locks in Patients Receiving Home Parenteral Nutrition

Catheter-related bloodstream infection (CRBSI) is one of the most common and potentially fatal complications in patients receiving home parenteral nutrition (HPN). In order to prevent permanent venous access loss, catheter locking with an antimicrobial solution has received significant interest and is often a favored approach as part of the treatment of CRBSI, but mainly for its prevention. Several agents have been used for treating and preventing CRBSI, for instance antibiotics, antiseptics (ethanol, taurolidine) and, historically, anticoagulants such as heparin. Nonetheless, current guidelines do not provide clear guidance on the use of catheter locks. Therefore, this review aims to provide a better understanding of the current use of antimicrobial locking in patients on HPN as well as reviewing the available data on novel compounds. Despite the fact that our current knowledge on catheter locking is still hampered by several gaps, taurolidine and ethanol solutions seem promising for prevention and potentially, but not proven, treatment of CRBSI. Additional studies are warranted to further characterize the efficacy and safety of these agents.

Comparing the cytotoxicity of taurolidine, mitomycin C, and oxaliplatin on the proliferation of in vitro colon carcinoma cells following pressurized intra-peritoneal aerosol chemotherapy (PIPAC)

BACKGROUND

Besides its known antibacterial effect commonly used in intraperitoneal lavage, taurolidine has been observed to possess antineoplastic properties. In order to analyse this antineoplastic potential in a palliative therapeutic setting, taurolidine (TN) was compared to mitomycin C (MMC) and oxaliplatin (OX), known antineoplastic agents which are routinely used in intraperitoneal applications, following pressurized intra-peritoneal aerosol chemotherapy (PIPAC).

METHODS

An in vitro model was established using a colon adenocarcinoma cell line (HT-29 human cells). Different experimental dosages of TN and combinations of TN, MMC, and OX were applied via PIPAC. To measure cell proliferation, a colorimetric tetrazolium reduction assay was utilized 24 h after PIPAC.

RESULTS

We demonstrated a cytotoxic effect of TN and OX (184 mg/150 mL, p < 0.01) on tumor cell growth. An increasing dosage of TN (from 0.5 g/100 mL to 0.75 g/150 mL) correlated with higher cell toxicity when compared to untreated cells (p < 0.05 and p < 0.01, respectively). PIPAC with OX and both OX and TN (0.5 g/100 mL) showed the same cytotoxic effect (p < 0.01). No significant impact was observed for MMC (14 mg/50 mL, p > 0.05) or MMC with OX (p > 0.05) applied via PIPAC.

CONCLUSIONS

The intraperitoneal application of TN is mostly limited to lavage procedures in cases of peritonitis. Our results indicate a substantial antineoplastic in vitro effect on colon carcinoma cells following PIPAC application. While this effect could be used in the palliative treatment of peritoneal metastases, further clinical studies are required to investigate the feasibility of TN application in such cases.

Preclinical characterization of AMPA receptor potentiator TAK-137 as a therapeutic drug for schizophrenia

The downregulation of the glutamate system may be involved in positive, negative, and cognitive symptoms of schizophrenia. Through enhanced glutamate signaling, the activation of the α-amino-3-hydroxy-5-methyl-4-isoxazole-propionic acid (AMPA) receptor, an ionotropic glutamate receptor, could be a new therapeutic strategy for schizophrenia. TAK-137 is a novel AMPA receptor potentiator with minimal agonistic activity; in this study, we used rodents and nonhuman primates to assess its potential as a drug for schizophrenia. At 10 mg kg-1 p.o., TAK-137 partially inhibited methamphetamine-induced hyperlocomotion in rats, and at 3, 10, and 30 mg kg-1 p.o., TAK-137 partially inhibited MK-801-induced hyperlocomotion in mice, suggesting weak effects on the positive symptoms of schizophrenia. At 0.1 and 0.3 mg kg-1 p.o., TAK-137 significantly ameliorated MK-801-induced deficits in the social interaction of rats, demonstrating potential improvement of impaired social functioning, which is a negative symptom of schizophrenia. The effects of TAK-137 were evaluated on multiple cognitive domains-attention, working memory, and cognitive flexibility. TAK-137 enhanced attention in the five-choice serial reaction time task in rats at 0.2 mg kg-1 p.o., and improved working memory both in rats and monkeys: 0.2 and 0.6 mg kg-1 p.o. ameliorated MK-801-induced deficits in the radial arm maze test in rats, and 0.1 mg kg-1 p.o. improved the performance of ketamine-treated monkeys in the delayed matching-to-sample task. At 0.1 and 1 mg kg-1 p.o., TAK-137 improved the cognitive flexibility of subchronic phencyclidine-treated rats in the reversal learning test. Thus, TAK-137-type AMPA receptor potentiators with low intrinsic activity may offer new therapies for schizophrenia.

Innovative substance 2250 as a highly promising anti-neoplastic agent in malignant pancreatic carcinoma - in vitro and in vivo

BACKGROUND

Former studies already revealed the anti-neoplastic properties of the anti-infective agent Taurolidine (TRD) against many tumor species in vitro and in vivo. Its anti-proliferative and cell death inducing capacity is largely due to its main derivative Taurultam (TRLT). In this study it could be demonstrated, that substance 2250 - a newly defined innovative structural analogue of TRLT - exhibits an anti-neoplastic effect on malignant pancreatic carcinoma in vitro and in vivo.

METHODS

The anti-neoplastic potential of substance 2250 as well as its mode of action was demonstrated in extensive in vitro analysis, followed by successful and effective in vivo testings, using xenograft models derived from established pancreatic cancer cell lines as well as patient derived tissue.

RESULTS

Our functional analysis regarding the role of oxidative stress (ROS) and caspase activated apoptosis showed, that ROS driven programmed cell death (PCD) is the major mechanisms induced by substance 2250 in pancreatic carcinoma. What is strongly relevant towards clinical practice is especially the observed inhibition of patient derived pancreatic cancer tumor growth in mice treated with this new substance in combination with its sharply higher metabolic stability.

CONCLUSION

These encouraging results provide new therapeutical opportunities in pancreatic cancer treatment and build the basis for further functional analysis as well as first clinical studies for this promising agent.

Taurolidine-citrate-heparin catheter lock solution reduces staphylococcal bacteraemia rates in haemodialysis patients

BACKGROUND

Infection is second only to cardiovascular disease as a cause of death in the haemodialysis (HD) population.

AIM

: To assess the effect of introducing catheter lock solution taurolidine-citrate-heparin to all tunnelled central venous catheters (TCVCs) on staphylococcal bloodstream infection rates in patients on chronic HD.

DESIGN

Observational, prospective analysis of the incidence rates of staphylococcal bacteraemic events in National Health Service (NHS) Greater Glasgow & Clyde and NHS Forth Valley between April 2011 and June 2013, with taurolidine-citrate-heparin catheter lock solution introduced July 2012.

METHODS

Data were collected each calendar quarter through a structured query language interrogation of the renal unit electronic patient record, with staphylococcal bacteraemic events expressed per 1000 vascular access exposed days. Comparison between pre- and post-intervention periods was made by student's t-testing.

RESULTS

Two hundred and thirty-nine staphylococcal bacteraemic events occurred over a total of 424,835 HD days in 565 patients; 81 events in 289,389 arterio-venous fistula or graft (AVF/AVG) HD days and 158 events in 135 446 TCVC HD days. Following the introduction of taurolidine-citrate-heparin, bacteraemic events in patients dialysing via a TCVC fell from 1.59/1000 HD days to 0.69/1000 HD days, P = 0.004. The staphylococcal bacteraemia rate in AVF/AVGs remained unchanged; 0.30 vs. 0.26/1000 HD days, P = 0.52.

CONCLUSIONS

Replacing heparin 5000 IU with Taurolidine-citrate-heparin as catheter lock solution was associated with a statistically significant 56% reduction in staphylococcal bloodstream infection rates in our TCVC HD population.

Switchable skin window induced by optical clearing method for dermal blood flow imaging

Optical imaging techniques have shown tremendous potential for assessing cutaneous microcirculation, but the imaging depth and contrast is limited by the strong scattering of skin. Current skin windows have to be fulfilled by surgical operation and suffer from some side effects. In this study, a switchable skin window was developed by topical application of an optical clearing agent (OCA) and saline on rat skin in vivo. The validity of the skin window was evaluated by the laser speckle contrast imaging technique, and the safety of OCA to the body was tested through histologic examinations. The results indicated that administration of OCA or saline on rat skin in vivo can open or close the window of skin repeatedly for three days. With the repair effect of hyaluronic acid and Vaseline, it is able to repeatedly visualize the dermal blood vessels and flow distribution. Long-term observation shows that there is no abnormal reflection in micro-structure, body weight, organ coefficients, histopathologic lesions, or toxic reactions compared with a control group. This switchable window will provide an effective tool not only for cutaneous microcirculation with laser speckle contrast imaging, but also for diagnosis and treatment of peripheral vascular diseases, including tumor research with various optical imaging techniques.

TRAIL and taurolidine enhance the anticancer activity of doxorubicin, trabectedin and mafosfamide in HT1080 human fibrosarcoma cells

BACKGROUND

Disseminated fibrosarcoma still represents a therapeutic dilemma because of lack of effective cytostatics. Therefore we tested tumor necrosis factor related apoptosis-inducing ligand (TRAIL) and taurolidine, in combination with established and new chemotherapeutic agents on human fibrosarcoma (HT1080).

MATERIALS AND METHODS

Human fibrosarcoma cells (HT1080) were incubated with doxorubicin, mafosfamide and trabectedin both alone and in combination with taurolidine and TRAIL. Vital, apoptotic and necrotic cells were quantified using flow cytometric analysis. Cell proliferation was analysed using a bromodeoxyuridine (BrdU) ELISA assay.

RESULTS

Single application of doxorubicin and trabectedin induced apoptotic cell death and significantly reduced the proliferation of HT1080 cells. In combination treatment, the addition of taurolidine and TRAIL resulted in a stronger reduction in the degree of cell viability when compared to single treatment. Trabectedin and taurolidine displayed a greater potential for inhibiting proliferation than did doxorubicin alone.

CONCLUSION

When combined with TRAIL and taurolidine, treatment with doxorubicin and trabectedin demonstrated stronger apoptosis-inducing and antiproliferative effects.

Unsuccessful application of taurolidine in the treatment of fungal peritonitis in peritoneal dialysis

Fungal peritonitis (FP) is a serious complication for peritoneal dialysis (PD) patients, determining hospitalization, technique failure, catheter loss and death. In the 2005 update, treatment recommendations for FP from the International Society of Peritoneal Dialysis (ISPD) advocate catheter removal immediately after fungi are identified by microscopy or culture. The availability of more effective medical treatments could therefore be of great importance. The aim of this report is to describe a case of a 43-year-old, diabetic, HIV positive PD patient with fluconazole resistant Candida peritonitis, who was treated with an i.p. taurolidine solution. Taurolidine is a non-antibiotic antimicrobial, with broad bactericidal and fungicidal properties. It has been used during surgery for lavage of the peritoneum in cases of peritonitis. Its mechanism of action is related to direct toxic action on micro-organisms, through a chemical reaction between active taurolidine derivatives and structures on the cell wall. Treatment failed because the patient had severe burning pain during i.p. administration of the drug, limiting its dose. PD catheter removal allowed complete recovery. It remains undetermined if, with different doses and methodology, taurolidine could be more effective in treating bacterial and/or fungal peritonitis. Currently, catheter removal remains the most effective therapy of fungal peritonitis.

Cogrinding enhances the oral bioavailability of EMD 57033, a poorly water soluble drug, in dogs

The oral bioavailability of EMD 57033, a calcium sensitizing agent with poor solubility, was compared in dogs using four solid dosage form formulation approaches: a physical blend of the drug with excipients, micronization of the drug, preparation of coground mixtures and spray-drying of the drug from a nanocrystalline suspension. The formulations contained generally accepted excipients such as lactose, hydroxypropylmethyl cellulose and sodium lauryl sulphate in usual quantities. Drug micronization and cogrinding was realized by a jet-milling technique. Nanoparticles were created by media milling using a bead mill. All formulations were administered orally as dry powders in hard gelatine capsules. While micronization increased the absolute bioavailability of the solid drug significantly compared to crude material (from nondetectable to 20%), cogrinding with specific excipients was able to almost double this improvement (up to 39%). With an absolute bioavailability of 26%, spray-dried nanoparticular EMD 57033 failed to show the superior bioavailability that had been anticipated from in vitro data. The control solution prepared with cyclodextrin was shown to have an absolute bioavailability of 57% (vs. i.v. infusion). It was concluded that cogrinding can be a useful tool to improve the bioavailability of poorly soluble drugs from a solid dosage form format.

Intra-abdominal use of taurolidine or heparin as alternative products to an antiadhesive barrier (Seprafilm) in adhesion prevention: an experimental study on mice

PURPOSE

Seprafilm (Genzyme Biosurgery, Cambridge, MA) remains a widely used product in postoperative adhesion prevention. This study was designed to compare the antiadhesive effects of taurolidine, heparin, and Seprafilm in a murine cecal abrasion model.

METHODS

Sixty male Balb/c mice underwent a cecal abrasion procedure and were randomized into four groups (n = 15 in each). Groups T, H, and S animals intraperitoneally received taurolidine, heparin, and Seprafilm, respectively, and Group C animals were reserved as control. Animals were killed on Day 21, and the severity of adhesions was evaluated with a scoring system ranging between 0 to 5. In addition, the localizations of the adhesions were questioned.

RESULTS

Five (1 in Group S and 4 in Group H) animals died before they were killed. The deaths were related to intra-abdominal bleeding, and mortality rate was significantly higher in Group H than those in other groups (P < 0.05 for each comparison). The severity of adhesions was significantly less in the study groups than Group C, and in Group H than Groups T and S (P < 0.05 for each comparison). In addition, adhesions located cecum over itself were significantly less in the study groups than the control group, and those between small bowel and cecum were significantly lower in Groups T and S than the control group (P < 0.05 for each comparison).

CONCLUSIONS

All products are effective in adhesion prevention. Heparin use provides the best results but may be associated with a higher mortality rate related to intra-abdominal bleeding. Taurolidine may be an alternative product to Seprafilm , but further studies are required.

Discovery of 1,1-dioxo-1,2,6-thiadiazine-5-carboxamide derivatives as cannabinoid-like molecules with agonist and antagonist activity

A series of new 2-substituted 1,1-dioxo-1,2,6-thiadiazine-5-carboxylate derivatives have been prepared from monosubstituted sulfamides in order to obtain N-substituted 1,1-dioxo-1,2,6-thiadiazine-5-carboxamides as novel cannabinoid derivatives, analogues of Rimonabant (SR141716A). Their potential functional activity on cannabinoid receptors has been evaluated in vitro and in vivo in mice, showing that two compounds (37 and 39) behave as cannabinoid agonists in vitro. Their potency is lower than that of the reference compound, WIN 55,212-2, but their efficacy is similar to that of this cannabinoid agonist, although no in vivo activity is observed. Another derivative (38) behaves as a cannabinoid antagonist both in vitro and in vivo, being its efficacy and potency similar to that of the well-known antagonist SR141716A.

Pharmacokinetics of taurolidine following repeated intravenous infusions measured by HPLC-ESI-MS/MS of the derivatives taurultame and taurinamide in glioblastoma patients

BACKGROUND AND OBJECTIVE

Taurolidine is known to have antimicrobial activity. Furthermore, at lower concentrations, it has been found to exert a selective antineoplastic effect in vitro and in vivo. The aim of this study was to investigate the pharmacokinetics of taurolidine in vivo following repeated intravenous infusion in a schedule used for the treatment of glioblastoma. As a prerequisite, the pharmacokinetics of taurolidine in human blood plasma and whole blood in vitro was investigated.

PATIENTS AND METHODS

The pharmacokinetics of taurolidine and its derivatives taurultame and taurinamide were investigated in human blood plasma and in whole blood in vitro using blood from a healthy male volunteer. During repeated intravenous infusion therapy with taurolidine, plasma samples were taken every hour for a period of 13 hours per day in seven patients (three male, four female; mean age 48.4 +/- 12.8 years, range 27-66 years) with a glioblastoma. Following dansyl derivatisation, the concentrations of taurultame and taurinamide were determined using a new method based on high-performance liquid chromatography (HPLC) online coupled to electrospray ionisation tandem mass spectrometry (ESI-MS/MS) in the multiple reaction monitoring mode. Under the experimental conditions used, taurolidine could not be determined directly and was back-calculated from the taurultame and taurinamide values.

RESULTS

The new HPLC-ESI-MS/MS method demonstrated high accuracy and reproducibility. In vitro plasma concentrations of taurultame and taurinamide remained constant over the incubation period. In whole blood in vitro, a time-dependent formation of taurinamide was observed. At the start of the incubation, the taurultame-taurinamide ratio (TTR) was 0.95 at an initial taurolidine concentration of 50 microg/mL, and 1.69 at 100 microg/mL. The concentration of taurultame decreased at the same rate as the taurinamide concentration increased, showing logarithmic kinetics. The calculated taurolidine concentration remained largely constant over the 6-hour incubation period. During repeated infusions in patients, calculated plasma concentrations of taurolidine showed a strong increase after the start of each infusion and continued to increase until the end of infusion, followed by a rapid decline. The TTR was found to fluctuate between 0.1 and 0.3, depending on the relation to the previous or next infusion period. The volume of distribution was markedly higher for taurolidine, taurultame and taurinamide than the plasma volume.

CONCLUSIONS

Taurolidine displayed a stable pattern of derivatives in plasma in vitro, whereas in whole blood, a time- and concentration-dependent conversion was apparent. In patients, the calculated average taurolidine plasma concentration, achieved with the repeated infusion regimen, was in the antineoplastic-effective concentration range. The tissue concentrations of taurolidine and taurultame are expected to be higher than the plasma concentrations, taking into account the calculated volumes of distribution. Repeated infusion of taurolidine is the therapeutically adequate mode of administration for the indication of glioblastoma.

EstimatingIn VivoAirway Surface Liquid Concentration in Trials of Inhaled Antibiotics

Antibiotic drugs exhibit concentration dependence in their efficacy. Therefore, ensuring appropriate concentration of these drugs in the relevant body fluid is important for obtaining the desired therapeutic and physiological action. Until recently there had been no suitable method available to measure or estimate concentration of drugs in the human airways resulting from inhaled aerosols or to determine the amount of inhaled antibiotics required to ensure minimum inhibitory concentration of a drug in the airway surface liquid (ASL). In this paper a numerical method is used for estimating local concentration of inhaled pharmaceutical aerosols in different generations of the human tracheobronchial airways. The method utilizes a mathematical lung deposition model to estimate amounts of aerosols depositing in different lung generations, and a recent ASL model along with deposition results to assess the concentration of deposited drugs immediately following inhalation. Examples of concentration estimates for two case studies: one for the antibiotic tobramycin against Pseudomonas aeruginosa, and another for taurolidine against Burkholderia cepacia are presented. The aerosol characteristics, breathing pattern and properties of nebulized solutions were adopted from two recent clinical studies on efficacy of these drugs in cystic fibrosis (CF) patients and from other sources in the literature. While the clinically effective tobramycin showed a concentration higher than the required in vivo concentration, that for the ineffective taurolidine was found to be below the speculated required in vivo concentration. Results of this study thus show that the mathematical ASL model combined with the lung deposition model can be an effective tool for helping decide the optimum dosage of inhaled antibiotic drugs delivered during human clinical trials.

Peritoneal instillation of taurolidine or polihexanide modulates intestinal microcirculation in experimental endotoxemia

BACKGROUND AND AIMS

Treatment of peritonitis may include peritoneal lavage/instillation with anti-infective agents like taurolidine or chlorhexidine.

MATERIALS AND METHODS

We examined the effects of peritoneal instillation (INST, 5-ml solution) with taurolidine (TAURO) or polihexanide (POLI-LS) on intestinal microcirculation using intravital microscopy (IVM) in experimental endotoxemia (15 mg/kg lipopolysaccharide i.v.; LPS) in the rat (n = 8 each group), their direct effects on local small blood vessels, aortal rings, and myocardial strips in vitro, as well as plasma interleukin levels.

RESULTS

It was found that LPS produced hypotension (98.8 +/- 9.5 vs 130.4 +/- 10.5 mmHg; mean arterial pressure [MAP], mean +/- standard deviation [SD]), which was further pronounced after INST of TAURO (78.8 +/- 10.8; P < 0.005) or POLI-LS (78.1 +/- 6.0; P < 0.001). IVM revealed a reduction in temporary adhering leucocytes and an increase in firmly adhering leucocytes after INST with TAURO and POLI-LS. Both agents reduced functional capillary density either in the mucosa (POLI-LS vs sham: 259.7 +/- 54 cm/cm(2) vs 337.1 +/- 35.5) or longitudinal muscular layer in LPS rats (TAURO vs sham: 119.8 +/- 14.8 vs 153.7 +/- 11.0). POLI-LS induced local vasodilatation, whereas TAURO induced small vasoconstriction; in vitro, both agents showed vasodilating properties and did not have any effect on myocardial strip contraction.

CONCLUSION

Some of the observed microcirculatory changes could be a result of the direct vascular effects of these agents.

The pharmacokinetics of taurolidine metabolites in healthy volunteers

Taurolidine is an experimental antibacterial and antiendotoxic compound whose clinical utility as an antitumor agent is being investigated in human clinical trials. Taurolidine in aqueous solution exists in equilibrium with taurultam. Taurultam is subsequently transformed to taurinamide. The pharmacokinetic profiles of these metabolites are not well established. In this study, 18 healthy volunteers were administered 5.0 g of taurolidine in 250 mL of 5% polyvinylpyrrolidone in water over 2, 1, or 0.5 hours by intravenous infusion in a parallel-group design. All subjects noted discomfort at the infusion site, although there were no serious adverse events. t(max) generally occurred at the end of infusion for taurinamide, whereas that of taurultam was reached before completion of infusion. The taurolidine metabolite taurultam demonstrated a shorter half-life and lower systemic exposure than taurinamide. Shortening of infusion duration increased the C(max) and AUC of taurultam. Changes in infusion rate did not substantially change the pharmacokinetic parameters of taurinamide.

Instillation of taurolidine/heparin after laparotomy reduces intraperitoneal tumour growth in a colon cancer rat model

OBJECTIVE

To investigate whether irrigation of the abdominal cavity after laparotomy for caecum resection with taurolidine/heparin or adhesion prophylactic substances reduces intraperitoneal tumour growth or the local recurrence rate in a colon carcinoma rat model.

METHODS

60 BDIX rats underwent caecum resection after intraperitoneal inoculation of 1 x 10(4) colon carcinoma cells (DHD/K12/TRb). Intergel, Interceed, taurolidine/heparin or NaCl 0.9% were intraperitoneally applied after randomisation. Finally, the total number and total weight of intraperitoneal metastases were determined as well as the adhesion score according to Moreno. Metastatic tissue was examined histologically and immunohistochemically (E-cadherin, CD44, beta(1)-integrin).

RESULTS

Taurolidine/heparin significantly reduced not only the total number (3 vs. 11 in the control group) but also the total weight (65 vs. 330 mg) of intraperitoneal metastases in comparison to the control group (p = 0.003 and p = 0.005). E-Cadherin expression in the metastatic tissue of animals treated with taurolidine/heparin was significantly decreased (p = 0.016).

CONCLUSION

Taurolidine/heparin effectively reduces intraperitoneal tumour growth when used as an intraoperative lavage. These results represent a good rationale for intraoperative adjuvant irrigation with taurolidine/heparin during resection of colon cancer.

High doses of taurolidine inhibit advanced intraperitoneal tumor growth in rats

BACKGROUND

The antitumor agent taurolidine (TRD) affects tumor growth in animals. Thus far, no animal studies have been published concerning the systemic or local toxicity and the effectiveness of long-term intraperitoneal (i.p.) and intravenous (i.v.) administration on advanced tumor growths.

MATERIALS AND METHODS

In a first experiment (A) the systemic toxicity of the liver and kidneys was examined only after i.v. treatment in 40 rats (BD IX). For local toxicity the superior vena cava (SVC) was histologically analyzed. In a second study (B) 20,000 colon adenocarcinoma cells (DHD/K12/TRb) were initially applied i.p. after laparotomy in 80 rats (BD IX). After 28 days a port catheter system was placed in the SVC and left for 1 week. The animals were randomized into eight groups (n = 10) and received a 7-day treatment (eight hourly, 1 ml): 1, 2, 3% TRD or Ringer's solution (control group) either i.p. or i.v. Total i.p. tumor weight was measured 4 weeks after the end of the therapy. Side effects on differential blood counts and animal weight changes were examined.

RESULTS

No organ lesions were detected in liver, kidneys, and SVC in experiment A. The i.v. administration of 2% TRD (P = 0.034) and 3% TRD (P = 0.05) as well the i.p. application of 2% TRD (P = 0.05) decreased the development of advanced i.p. tumor lesions. No changes of differential blood count nor relevant animal weight changes resulted. Three port catheter-related infections were examined.

CONCLUSIONS

TRD does not impair the liver tissue, kidneys, SVC, and leucopoiesis. The intravenous therapy of 2% TRD is safe and anti-tumorigenic in advanced local tumor growth in rats.

Taurolidine lock: The key to prevention of recurrent catheter-related bloodstream infections

The literature shows that repeated courses of antibiotics and catheter removals in a subset of patients suffering from multiple catheter-related bloodstream infections (CRBSI), are unlikely to prevent recurrence. In acceding to preventative strategies, we report our application of the antimicrobial chemotherapeutic Taurolidine used as a daily flush solution in seven home TPN patients suffering from multiple episodes. A pretreatment infection rate of 10.8 infections per 1000 catheter days decreased to 0.8 after treatment.

Effects of increasing doses of a bolus injection and an intravenous long-term therapy of taurolidine on subcutaneous (metastatic) tumor growth in rats

BACKGROUND

Experimental studies have shown that taurolidine suppresses intraperitoneal tumor growth following local application in rats. In opposite, a single intravenous therapy affected neither intraperitoneal nor subcutaneous growth of malignancies. Thus, an intravenous long-term therapy with taurolidine was investigated in rats after administration of a subcutaneous tumor load. VEGF and TNFalpha production and their effects on tumor growth have not been elucidated so far.

METHODS

VEGF and TNFalpha levels of rat colon adenocarcinoma cells (DHD/K12/TRb) were analyzed in the supernatant undergoing treatment of increasing taurolidine doses in vitro. Besides the cell experiments rats were treated intravenously. At the beginning of the operation, 10 000 colon adenocarcinoma cells were applied subcutaneously at the back of the rats. Then the animals (n = 80, BD IX rats) were randomized into eight groups and underwent a standardized midline laparotomy for 30 min. At the end of the operation the animals were given either a bolus (1 ml Ringer's solution) or a long-term intravenous therapy (7 days, eight-hourly 1 ml 1%, 2%, or 3% taurolidine) were performed. For long-term therapy, a jugularis vein port catheter system was placed and left for 1 week. The influence on subcutaneous tumor growth, animal growth, general side effects and leukocyte/granulocyte levels were analyzed. Total tumor weights were determined 4 weeks after cell application.

RESULTS

The VEGF and TNFalpha levels decreased rapidly after taurolidine therapy with low doses in vitro. The subcutaneous tumor growth showed a downtrend of tumor weight (P = 0.075) with a statistical significance in solid tumor counts (P = 0.04) at the back of the animals. A slight and temporary depression in animal growth was observed only in long-term therapy groups. Independent of the therapeutic agents and the application forms, the operation itself caused a slight leukopenia shortly after the operation compensated by a moderate leukocytosis in the following course. Fast injections of taurolidine led to a reduction of breathing rate.

CONCLUSIONS

Only the intravenous long-term therapy of 3% taurolidine led to a slight downregulation in subcutaneous tumor growth. The changes of leukocyte counts were not affected by taurolidine. Fast injections have to be avoided. The findings prompted us to start new experiments to determine the influence of increasing doses of taurolidine on progressive tumor growth in rats.

Impact of taurolidine on the growth of CC531 coloncarcinoma cells in vitro and in a laparoscopic animal model in rats

BACKGROUND

The object of this study was to examine the effect of taurolidine on intraabdominal tumor growth in a laparoscopic animal model. We tested the cytotoxic, antiadhesive, and anti-invasive effects of this substance on CC531 adenocarcinoma cells in vitro and in vivo using WAG rats.

METHODS

For in vitro experiments, Transwell dual chambers with polycarbonate filters coated with 100 microg/cm2 Matrigel were used to investigate the effects of 5, 10, and 20 microl of 2.0% taurolidine on the invasion of 1 x 10(5) CC531 adenocarcinoma cells. For the adhesion assays, tumor cells were applied onto microtiter plates coated with 5, 10, and 20 microl taurolidine and 0.9% NaCl solution for the control group subsequently. For in vivo experiments, 40 WAG rats were randomized into three therapy groups and one control group. All animals underwent laparoscopy and received 1 ml of CC531 adenocarcinoma cells (5 x 10(6) cells/ml) intraabdominally at the beginning of the procedure. According to the randomization, the rats were administered taurolidine with different concentrations or 1 ml of 0.9% NaCl solution for the control group. After 21 days, the animals were killed and the intraabdominal tumor weight was determined.

RESULTS

For the in vitro experiments, we found a moderate cytotoxicity and a significant inhibition of tumor cell adhesion and invasion (p < 0.01) by all taurolidine concentrations used in the assay. For in vivo experiments, the application of all concentrations of taurolidine significantly decreased the intraperitoneal tumor weight (p < 0.001).

CONCLUSION

Taurolidine significantly decreases adhesion and invasion of CC531 adenocarcinoma cells in vitro and significantly diminishes tumor growth in vivo. This may offer additional therapeutic options for laparoscopic surgery for colorectal cancer.

Irrigation of port sites: prevention of port site metastases?

INTRODUCTION

Port site metastases can occur when free viable tumor cells implant at trocar wounds. Irrigation of port sites with cytotoxic agents has been suggested to prevent port site metastases. The objective of this study is to assess whether tumor growth at port sites can be reduced by irrigation of these port sites.

METHODS

WAG rats were insufflated with CO(2) for 20 minutes and 5 x 10(5) CC531 tumor cells were injected intraperitoneally. Port sites were irrigated after completion of the pneumoperitoneum with povidone-iodine, a mixture of taurolidine and heparin, or sodium chloride. Controls did not undergo any irrigation of port sites. In experiment 1, all 16 rats had all 4 irrigation modalities. In experiment 2, four groups of 20 rats had one type of irrigation on two trocar wounds. Tumor growth was evaluated 4 weeks after the procedure.

RESULTS

No difference in tumor growth at trocar wounds was found between any type of irrigation and controls in both experiments.

CONCLUSION

In this experimental model, no beneficial or adverse effects of irrigation of port sites could be shown.

Mechanistic and antineoplastic evaluation of taurolidine in the DU145 model of human prostate cancer

Taurolidine (TRD) was designed in the 1970s as a broad-spectrum antibiotic and is used clinically at high doses without systemic toxicity. We have found that this agent possesses cytotoxic activity in human tumor cell lines and antineoplastic activity in mice bearing i.p. human tumor xenografts. We now report the mechanism by which TRD induces cell death in DU145 human prostate tumor cells. The IC50 (3 days) of TRD in this model was 16.8+/-1.1 microM. Cytotoxicity was associated with DNA debris and increased membrane phosphatidylserine externalization, both suggesting the induction of apoptosis. This was confirmed by the ability of TRD to induce PARP cleavage in these cells, an effect prevented by coexposure to the pan-caspase inhibitor zVAD-FMK. TRD exposure also resulted in the appearance of cytochrome c in the cytoplasm, procaspase 9 activation within 2 h of drug exposure and procaspase 8 activation 4 h after exposure. Parallel experiments revealed that cytochrome c appearance in the cytoplasm was not blocked by preexposure to zVAD-FMK, while activation of both procaspase 9 and procaspase 8 was prevented. Finally, antineoplastic activity was assessed in mice bearing subcutaneous xenografts of DU145 cells. Initial studies quantitated the toxicity of three i.p. injections of TRD, administered as one injection on three alternate days per week, at doses ranging from 500 to 700 mg/kg per injection. The 500 mg/kg dose produced about 7% mortality after three cycles and effectively inhibited tumor growth. Thus, TRD induced mitochondrial-mediated apoptosis in DU145 human prostate tumor cells and this effect could be exploited for therapeutic advantage.

Taurolidine-Fibrin-Sealant-Matrix using spray application for local treatment of brain tumors

Malignant gliomas tend to recur in the vast majority of cases. Recurrent gliomas may arise from vital tumor cells present in this zone around the resection margin. It appears promising to combine tumor resection with local chemotherapy using an antineoplastic, but non-toxic agent. Taurolidine exerts a selective antineoplastic effect by induction of programmed cell death and has anti-angiogenic activity. Fibrin sealant is completely degradable and firmly adheres to brain tissue, suggesting that it would provide a suitable matrix for taurolidine delivery--a Taurolidine-Fibrin-Sealant-Matrix (TFM)--in the local treatment of brain tumors. The potential of local delivery of taurolidine out of a fibrin sealant matrix was investigated. Taurolidine could be suspended homogeneously in both the thrombin and the procoagulant protein components of the fibrin sealant. The fibrin sealant matrix was a suitable carrier for the suspension of taurolidine at a concentration that ensured the release of therapeutically effective amounts of the drug over a period of 2 weeks in vitro. The antineoplastic action of taurolidine was not affected by embedding in the fibrin sealant matrix. The described drug delivery system may be suitable for local taurolidine treatment of brain tumors following complete or partial resection or of tumors that are non-resectable because of their location.

Prevention of dialysis catheter-related sepsis with a citrate-taurolidine-containing lock solution

BACKGROUND

The use of haemodialysis catheters is complicated by catheter-related sepsis. Intraluminal colonization of the catheter with bacteria is important in the pathogenesis of catheter-related sepsis. The use of a catheter lock solution containing the antimicrobial taurolidine might prevent bacterial colonization, thereby reducing the incidence of catheter-related sepsis.

METHODS

In a randomized prospective trial, patients receiving a dialysis catheter were included and catheters were locked with either heparin or a citrate-taurolidine-containing solution. Blood cultures drawn from the catheter lumen were routinely taken every 2 weeks and at time of removal of the catheter to detect bacterial colonization. Catheter-related sepsis and exit-site infections were registered for both groups.

RESULTS

A total of 76 catheters were inserted in 58 patients. The incidence of catheter colonization progressed slowly over time with no differences between dialysis catheters filled with heparin or citrate-taurolidine-containing solution. The number of exit-site infections was also similar between both groups. In the heparin group, four cases of catheter-related sepsis occurred as opposed to no sepsis episodes in the patients with catheters locked with the citrate-taurolidine-containing solution (P<0.5). No side effects with the use of citrate-taurolidine catheter lock solution were noted.

CONCLUSIONS

This study shows that catheter filling with a solution containing the antimicrobial taurolidine may significantly reduce the incidence of catheter-related sepsis. Taurolidine appears to be effective and safe and does not carry the risk for side effects that have been reported for other antimicrobial lock solutions containing gentamicin or high concentrations of citrate.

Local and systemic chemotherapy with taurolidine and taurolidine/heparin in colon cancer-bearing rats undergoing laparotomy

Experimental studies in the therapy of malignant abdominal tumors have shown that different cytotoxic agents suppress the intraperitoneal tumor growth. Nevertheless, a general accepted approach to prevent tumor recurrences does not exist. Following subcutaneous and intraperitoneal injection of 10(4) colon adenocarcinoma cells (DHD/K12/TRb), the influences of both taurolidine or taurolidine/heparin on intraperitoneal and subcutaneous tumor growth was investigated in 105 rats undergoing midline laparotomy. The animals were randomized into 7 groups and operated on during 30 min. To investigate the intraperitoneal (local) influence of either taurolidine or heparin on tumor growth, the substances were applied intraperitoneally. Systemic and intraperitoneal effects were evaluated after intravenous injection of the substances. Both application forms were also combined to analyze synergistic effects. Tumor weights, as well as the incidence of abdominal wound metastases, were determined four weeks after the intervention. In order to evaluate the effects of the agents, blood was taken to determine the peripheral leukocytes counts. Intraperitoneal tumor growth in rats receiving intraperitoneal application of taurolidine (median 7.0 mg, P = 0.05) and of taurolidine/heparin (median 0 mg, P = 0.02) was significantly reduced when compared to the control group (median 185 mg). The simultaneous instillation of both agents also reduced the intraperitoneal tumor growth (median 4 mg, P = 0.04), while the intravenous injection of the substances caused no local effect. In contrast, the subcutaneous tumor growth did not differ among all groups. In all groups, abdominal wound recurrences were rare and did not differ. Independent of the agents and the application form, the operation itself caused a slight leukopenia shortly after the operation and a leukocytosis in the following course. Intraperitoneal therapy of either taurolidine or in combination with heparin inhibits local tumor growth and abdominal wound recurrences in rats undergoing midline laparotomy. Neither the intraperitoneal nor the intravenous application or the combination of the two agents influenced the subcutaneous tumor growth. The substances did not alter the changes of peripheral leukocytes.

Effects of taurolidine and octreotide on tumor growth and lipid peroxidation after staging-laparoscopy in ductal pancreatic cancer

Irrigation with taurolidine after laparoscopy decreases tumor growth in colon carcinoma. In pancreatic cancer subcutaneous therapy with octreotide decreases oxidative stress and carcinogenesis as well. However, it is still unclear, whether irrigation with taurolidine or octreotide after laparoscopic pancreatic biopsy reduces tumor growth in pancreatic cancer as well. In 60 Syrian hamsters ductal pancreatic adenocarcinoma was induced by weekly injection of 10mg/kg body weight N-nitrosobis-2-oxopropylamine s.c. for 10 weeks. In week 16 laparoscopic pancreatic biopsy by use of carbon dioxide was performed (gr. 1, n = 20) with subsequent laparoscopic irrigation with taurolidine (gr. 2, n = 20) or octreotide (gr. 3, n = 20). In week 25 hamsters were sacrificed. Our results show that macroscopic visible primary tumors were found in only one animal of the taurolidine group (5.9%), compared to 42.1% in the saline and 62.5% in the octreotide group (P<0.05). Carcinomas were smaller after saline (6+/-23 mm(2)) than after octreotide irrigation (70+/-120 mm(2), P<0.05). In conclusion this study showed that laparoscopic irrigation with taurolidine after pancreatic biopsy inhibited tumor growth in ductal pancreatic adenocarcinoma.

A randomized double-blinded placebo-controlled crossover trial of nebulized taurolidine in adult cystic fibrosis patients infected with Burkholderia cepacia

Burkholderia cepacia is an aggressive pathogen that colonizes cystic fibrosis (CF) patients, causing greatly increased morbidity and mortality. It is resistant to most antibiotics, but sensitive in vitro to a novel agent, taurolidine. This has not previously been used against B. cepacia, nor given in nebulized form. We assessed the effect of nebulized taurolidine on United Kingdom epidemic (ET12) B. cepacia infection in 20 adult CF patients attending our regional adult cystic fibrosis outpatient clinic using a prospective, randomized, double-blinded placebo-controlled crossover trial. Nebulized taurolidine (4 mL 2% solution) or saline (4 mL 0.9% solution) was given twice daily. Each arm lasted 4 weeks, with a 2-week intervening washout period. Sputum B. cepacia colony counts (primary outcome measure), spirometry, and symptoms (secondary outcome measures) were assessed. Eighteen patients completed the study. There was no change in B. cepacia colony counts or spirometry, nor symptom scores. We conclude that, although taurolidine is well tolerated in nebulized form, in this study it had no in vivo anti-B. cepacia activity.

Chemical alternatives to methyl bromide for the control of root-knot nematodes in greenhouses

The complete phase-out of methyl bromide from use in developed countries by 1 January 2005 will cause many problems in agricultural industries that are now heavily reliant on its use. Three field experiments were established to compare management tactics on tomato and cucumber in commercial greenhouses naturally infested with root-knot nematodes (Meloidogyne spp). Reduction of nematode juveniles in soil and roots to nil detection levels was observed in all plots following soil fumigation with methyl bromide. A significant reduction of nematode juveniles and root-galling index was observed in plots treated with metham-sodium, dazomet and 1,3-dichloropropene compared with the control and plots treated with non-fumigant nematicides. Reduction of the nematode population led to an increase in fruit yield. However, data collected from the second cultivation season indicated that single control methods such as fumigant or contact nematicides alone cannot drastically decrease initial nematode population and those nematodes which escape control lead to population increase by the end of the cropping season.

Influence of intraperitoneal and systemic application of taurolidine and taurolidine/heparin during laparoscopy on intraperitoneal and subcutaneous tumour growth in rats

BACKGROUND

Recent clinical and experimental studies investigated the problem and possible pathomechanisms of portsite metastases after laparoscopic resection of malignant tumours. A generally accepted approach to prevent these tumour implantations does not exist so far.

METHODS

After subcutaneous and intraperitoneal injection of 10(4) cells of colon adenocarcinoma (DHD/K12/TRb) the influences of either taurolidine or taurolidine/heparin on intraperitoneal and subcutaneous tumour growth were investigated in 105 rats undergoing laparoscopy with carbon dioxide. The animals were then randomised into seven groups. A pneumoperitoneum was established using carbon dioxide for 30 min (8 mmHg). Three incisions were used: median for the insufflation needle, and a right and left approach in the lower abdomen for trocars. To investigate the intraperitoneal (local) influence of either taurolidine and heparin on tumour growth the substances were instilled intraperitoneally. Systemic effects were expected when the substances were applied intravenously (iv). Synergistic influences were tested when both application forms were combined. The number and the weight of tumours as well as the incidence of abdominal wall and port-site metastases were determined four weeks after intervention. Blood was taken to evaluate the influences of taurolidine and heparin on systemic immunologic reactions: seven days before laparoscopy. two hours, two days. seven days, and four weeks after operation, and the peripheral lymphocytes were determined.

RESULTS

Intraperitoneal (ip) tumour weight in rats receiving taurolidine (median 7 mg) and taurolidine/heparin (0 mg) intraperitoneally was significantly reduced when compared to the control group (52 mg) (P = 0.001). There was no difference of subcutaneus tumour growth among the groups (P = 0.4). Trocar recurrences were decreased when taurolidine was applied ip (3115). ipiv (4/15), and ip in combination with heparin (4/15) in comparison to the control group (10/15). Immediately after intervention treated and untreated groups showed a peripheral lymphopenia.

CONCLUSIONS

The intraperitoneal therapy with taurolidine and the combination with heparin inhibits the intraperitoneal tumour growth and trocar recurrences. Neither the intraperitoneal nor the systemic application or the combination of taurolidine and heparin did reduce the subcutaneous tumour growth. The intervention caused a lymphopenia which was compensated on day two.

Effect of taurolidine on the normal eyelid and conjunctival flora

PURPOSE

The effectiveness of the topical taurolidine was evaluated in eradicating or reducing microorganisms in the normal flora of human eyes in a randomized controlled study and analyzed also the irritating effects of taurolidine on the ocular surface.

METHODS

One hundred and twenty eyes of 110 patients awaiting cataract surgery were randomly divided into four groups consisting of 30 eyes each. The first group received 0.05% taurolidine, the second received 0.3% gentamicin, the third received vehicle eyedrops and the fourth received saline to the preoperative eye four times daily for two days. Cultures were obtained from the eyelids and conjunctivas of all subjects prior to the therapy and again at the end of 48 hours. Micro-biological identification and colony counts were performed by standard laboratory methods, and the results were compared. The patients were clinically evaluated for symptoms and signs at the end of therapies.

RESULTS

Taurolidine and gentamicin produced a significant decrease from the basal bacteriological state: the number of colonies (p < 0.01 for taurolidine, p < 0.01 for gentamicin) was reduced by both agents. Staphylococcus epidermidis was the most common microorganism isolated before therapy, and the number of its colonies was significantly reduced in taurolidine-treated (p < 0.001) and gentamicin-treated (p < 0.01) subjects. There was no significant difference in terms of the irritating effects for all therapies tested (p > 0.05).

CONCLUSIONS

Taurolidine solution with its unique properties is an effective antimicrobial agent for reducing the number of bacteria in the flora of the eye. Taurolidine appears to be well tolerated and offers promise as a potential new antimicrobial drug.

Modulation of tumor-induced lethality after pneumoperitoneum in a mouse model

BACKGROUND

To the authors' knowledge, a generally accepted approach to prevent increased intraabdominal tumor implantation after laparoscopic cancer surgery does not exist.

METHODS

One week after establishing an ovarian carcinoma cell line in black mice intraabdominally (n = 156), a carbon dioxide pneumoperitoneum (Group 1: n = 78) was administered. The effect of this procedure on tumor-induced lethality and the therapeutic effect of mitoxantrone and taurolidin mixed with heparin and sodium chloride was investigated. The different drugs were added immediately after the release of the pneumoperitoneum and after 48 hours. The 78 control animals received the drugs at the same time without preexisting pneumoperitoneum. Survival time was registered.

RESULTS

The survival time was reduced significantly in all pneumoperitoneum groups compared with the corresponding control group without pneumoperitoneum. The effect of mitoxantrone on survival time (mean, 62.08 days) was diminished significantly by the application of a pneumoperitoneum (mean, 34.27 days). Taurolidine/heparin appeared to have a positive effect on survival time only in the case of a previous pneumoperitoneum (mean of 21.12 days vs. mean of 16.04 days in the pneumoperitoneum control group; P < 0.001).

CONCLUSIONS

The induction of a pneumoperitoneum appears to decrease survival time by increasing tumor cell growth and decreases the efficacy of intraperitoneal chemotherapy. The effects of pneumoperitoneum appear to be reduced by the use of heparin/taurolidine, which theoretically blocks extracellular matrix binding domains and inhibits the production of interleukin-1.

Feasibility of therapeutic pneumoperitoneum in a large animal model using a microvaporisator

BACKGROUND

Multimodal therapy is used increasingly in advanced gastrointestinal tumors. Potential benefits of using an intraoperative adjuvant therapy during laparoscopy for cancer have been documented in animal studies. The aim of this study was to develop a device that could deliver such an intraoperative drug therapy.

METHODS

We developed a micropump suitable for minimally invasive surgery procedures that allowed microdroplets of therapeutic substance to be distributed into the pneumoperitoneum (CO2), creating a "therapeutic pneumoperitoneum." A closed-loop control system regulates drug delivery according to the gas flow. In vitro, the micropump is able to aerosolize various aqueous and ethanol solutions, including cytostatic and bacteriostatic drugs and adhesion-modulating agents. The size of the microdroplets has been optimized to prevent visual artifacts.

RESULTS

The micropump was tested in an animal model (pig). The system was inserted into a 5-mm trocar. After insufflation of a 12-mm CO2 pneumoperitoneum, laparoscopic sigmoid colon resections could be performed with no special difficulties. No fog developed, and no system-related complication was observed. At autopsy, the active principle was distributed to all exposed peritoneal surfaces.

CONCLUSIONS

As opposed to conventional peritoneal washing, therapeutic pneumoperitoneum reaches the entire peritoneal surface, allowing an optimal drug distribution. Drug diffusion into the tissues is enhanced by the intraperitoneal pressure. Precise determination of the instantaneous and total drug quantity is possible. Therefore, this drug delivery system has several advantages over conventional irrigation. Its potential domains of application are locoregional cancer therapy, prevention of port-site recurrences, immunomodulation, analgesia, peritonitis, and prevention of postoperative adhesions.

Taurolidine 2% as an antimicrobial lock solution for prevention of recurrent catheter-related bloodstream infections

BACKGROUND

This case report describes our preliminary data on the use of taurolidine as a lock technique. Taurolidine is a novel antimicrobial agent that has found a niche in Europe for prevention of bacteremia in home parenteral nutrition (HPN) patients who have multiple catheter-related blood-stream infections.

METHODS

A 29-year-old male with short bowel syndrome was admitted 18 times in 9 years for treatment of Gram-positive, Gram-negative, and yeast-associated catheter-related bloodstream infections. Management consisted of conventional antibiotic treatment in accordance with blood culture and sensitivity results as well as catheter removal in 10 cases. Ten months before the last infection, the patient was instructed to instil 1.5 mL taurolidine 2% daily into his central line after finishing his HPN infusion and has continued to do so 2 years to date.

RESULTS

The incidence of catheter-related bloodstream infections decreased from 8.5 to 1.5 infections per 1000 catheter days.

CONCLUSIONS

These data support previous observations made outside North America and suggest that taurolidine may prove to be an effective and safe antimicrobial agent for the prevention of recurrent catheter-related bloodstream infections.

New carriers for representative peptides and peptide drugs

3,5-Disubstituted tetrahydro-2H-1,3,5-thiadiazine-2-thione (THTT) derivatives; 4a-g were prepared and found to be a promising prodrug approach for peptide drugs. The pH profile for their degradation in aqueous buffer solutions was determined using HPLC technique and accounted for, in terms of specific base-catalyzed reactions. All of the compounds however, showed high acid-stability. Enzymatic (human serum) hydrolysis of the different derivatives offered an advantageous range of t1/2's, the property that permits controlling onset and duration of actions of drugs.

[Surgical therapy of pleural empyema with tauroline]

Empyema continues to be a significant problem in spite of improved surgical techniques and the use of new, more potent antimicrobial agents. This report describes our experience in the treatment of empyema at the Clemens Hospital in Münster, Germany, from 1990 to 1996. Basic to conservative treatment are closed drainage with intensive irrigation and instillation of Taurolin, a chemotherapeutic agent against bacterias, yeasts and mycetes. This treatment has been employed since 1990 and given 86 patients with just empyema or in combination with decortication. The superiority of this method to other methods of treatment is discussed on the basis of our results.

[Initial clinical experience with taurolidin instillation into the area of the middle area]

In this pilot study 2% taurolidin solution was used for irrigation of infected ears and instillation topically in 10 patients with severe purulent otitis media. The main purpose of the study was to find out whether the application of the taurolidin solution into the middle ear would cause significant pain or not. A slight increase in local pain was found sporadically but was not reason for withdrawing the drug. Twelve of 13 bacterial species isolated prior to treatment were eliminated during the trial, with the otorrhea of most patients stopping after just the first instillation. Audiometric evaluations during and 30 months after therapy did not reveal any ototoxic side effects. Tinnitus was not experienced by any patient during therapy. Overall findings demonstrated that local therapy with taurolidin for patients with severe purulent otitis media was very well tolerated and effective bacteriologically. There were also no therapy-related complications or ototoxic side effects.

Enantiomeric dissection of the effects of the inotropic agent, EMD 53998, in single cardiac myocytes

The effects of the thiadiazinone derivative, 5-[1-(3,4-dimethoxybenzoyl)-1,2,3,4-tetrahydrochinolin-6-yl]-6-met hyl-3,6- dihydro-2H-1,3,4-thiadiazin-2-on (EMD 53998), and of its (+)EMD 57033 and (-)EMD 57439 enantiomers, were tested on the contractile properties and cytosolic [Ca2+] ([Ca2+]i) transients of single intact guinea pig cardiac myocytes. Cells were loaded with the ester form of the fluorescent probe, indo-1, and bathed in a N-2-hydroxyethyl-piperazine-N'-2-ethanesulfonic acid-buffered solution at 25 degrees C (1 mM of CaCl2, 1 Hz stimulation rate). All three substances exerted a pronounced increase in twitch amplitude: the maximal effect of the racemate (380% of control value) was approximately the sum of the effects of its two enantiomers (186 and 236% of control value for the (+)- and (-)-enantiomer, respectively). The [Ca2+]i transient, measured as the 410-to-490 nm indo-1 fluorescence ratio transient after excitation, was increased by the racemate and its (-)-enantiomer (172 and 152% of control value, respectively), but was not increased by the (+)-enantiomer. The racemate and the (-)-enantiomer, but not the (+)-enantiomer, markedly reduced the contraction duration and [Ca2+]i transient duration. In unstimulated cells resting length was significantly reduced by the (+)-enantiomer, and this was accompanied by a decrease in indo-1 fluorescence; the (-)-enantiomer had no effect on either parameter. In the presence of 2,3 butanedione monoxime (BDM), which markedly reduces twitch amplitude by inhibiting cross-bridge mechanics, addition of the (+)-enantiomer restored the twitch contraction to above the pre-BDM level without augmenting the [Ca2+]i transient. In contrast, the (-)-enantiomer failed to reverse the BDM-induced contractile depression, even though it caused a significant increase of the [Ca2+]i transient. Thus, in intact cells the positive inotropic effect of EMD 53998 is due to specific properties of its enantiomers: the (-)-enantiomer has adenosine 3',5'-cyclic monophosphate-like effects (increase in amplitude and reduction of [Ca2+]i transient and contraction durations), whereas the (+)-enantiomer enhances the myofilament-Ca2+ interaction.

[The effect of taurolin on endogenous immunity and pathogen elimination in human peritonitis]

The influence of taurolin on phagocytosis-related defense functions and on the elimination of bacteria has been investigated in a controlled study. Particle opsonisation, a prerequisite for sufficient phagocytosis, was undisturbed in presence of up to 0.1% taurolin. Intraabdominal taurolin application did not diminish the leukocyte influx into the abdominal cavity. Opsonic capacity of peritoneal exudate was low in the taurolin group. These exudates contained more severe bacterial contamination, suggesting that this deficit was due to enhanced specific consumption of opsonins. Taurolin treatment resulted in a marked reduction of bacterial growth. Thus the substance provides antiseptic capacities without afflicting the physiological defense systems.

The metabolic disposition of an orally active pyridyl thiadiazinone cardiotonic agent (MPTD) in rat and baboon

1. Oral absorption and bioavailability of the orally active cardiotonic agent, (6RS)-6-methyl-5-(pyrid-4-yl)-3H,6H-1,3,4-[6-14C]thiadiaz in-2-one (MPTD) (5 mg/kg), in rat and baboon were high. Peak blood concentrations of MPTD and total radioactivity were reached by 1.5-4 h when MPTD accounted for 60-70% of total radioactivity. In both species, elimination of MPTD from blood was rapid (t 1/2 = 3-4 h), although total nonspecific radioactivity was eliminated more slowly. 2. Radioactivity was rapidly eliminated by both species mainly into urine. In rat, about 3% dose was collected as 14CO2 and 2% remained in the carcass after 4 days. Recovery from baboon was incomplete (78-86%). 3. Examination of urine indicated extensive metabolism of MPTD showing a marked species difference. In baboon, MPTD was metabolized largely by glucuronidation at the pyridyl nitrogen to yield a quaternary ammonium conjugate and only about 1% of the dose was excreted unchanged. In rat, the major urinary component was unchanged MPTD and no glucuronide conjugate was found. Both species formed the pyridine N-oxide of MPTD as well as a number of unidentified minor components. 4. Distribution of radioactivity in rat was rapid and extensive. In general, elimination from tissues was also rapid, although radioactivity was eliminated much more slowly from the nasal and bronchiolar epithelium and from the preputial gland.

Taurolidine instillation as therapy for empyema thoracis. A prospective study of 50 patients

Fifty patients with chronic empyema thoracis, without bronchopleural fistula, were treated by drainage and twice-daily instillations of 2% taurolidine (Taurolin; Continental Ethicals) for 14 days. No antibiotics were used. Forty-three patients completed the treatment and 7 were withdrawn from the trial, 3 because of evidence of bronchopleural fistula and 1 each because of pain during instillation, associated chest-wall cellulitis, an unexplained, acute epilepsy-like episode during instillation, and inadvertent administration of antibiotics. All 43 patients who completed the trial showed an excellent clinical response with control of the local and systemic toxic effects of sepsis. A rapid falling-off in the volume and purulence of pleural drainage fluid was noted. Twenty-four of the 43 patients (55,8%) were rendered bacteriologically sterile by the treatment. Instillation of 2% taurolidine was therefore an effective form of monotherapy in cases of chronic empyema thoracis without bronchopleural fistula.

[Appendicular peritonitis: comparative study of antibiotic therapy and a topical bactericidal agent]

Fifty four patients operated on for appendicular peritonitis where randomly divided. In the first group intravenous Dalacin C and Spectacilline were given during five days postoperatively; in the second, Taurolin, a bactericid, was administered by intraperitoneal route. There was a statistical difference in either treatment, neither on intraperitoneal nor parietal septic complications. The use and way of prophylactic antibiotic administration are discussed.

[Nebacetin and taurolin as intraoperative disinfectant solutions in surgery of the locomotor system (author's transl)]

The anti-infective preventive action of intraoperative disinfection with physiological solution containing antibiotics, appears to be firmly established, judging from numerous publications. Since germs are showing a world-wide increasing resistance, the search for antibiotics which continue to be effective must be kept up, but alternative suggestions are equally necessary. Some publications have already been presented indicating that success similar to that previously obtained with antibiotics is possible by using disinfectants in the prophylaxis and treatment of infections. Hence, a comparative study was conducted using the non-absorbable broad-spectrum antibiotic Nebacetin and the disinfectant Taurolin in a 1% solution with a group of patients subjected to a total of 7699 major and minor surgical operations. Prospectively, early infections during the stay of the patient in the hospital, als well as disturbed wound healing, were included. No significant difference was found in the number of infections and the rate of disturbed wound healing. Indirectly, it is possible to conclude with the help of results from literature that the disinfectant Taurolin is suitable as an addition to intra-operative rinsing in the prophylaxis of infections.