Azithromycin uptake by tissue cultured epithelial cells.
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Biomedical subjects
Publications and source records attributed to I García.
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The penetration of trovafloxacin into human polymorphonuclear leukocytes (PMNs), human peritoneal macrophages, and tissue-cultured epithelial cells (McCoy cells) was evaluated. The cellular concentration to extracellular concentration (C/E) ratios of trovafloxacin were greater than 9 for extracellular concentrations ranging from 0.5 to 25 micrograms/ml. The uptake of trovafloxacin by PMNs was rapid, reversible, nonsaturable, not energy dependent, and significantly increased at 4 degrees C. Ingestion of opsonized zymosan, but not opsonized Staphylococcus aureus, significantly increased the amount of PMN-associated trovafloxacin. This agent at concentrations of 0.5 and 1 microgram/ml induced a greater reduction in the survival of intracellular S. aureus in PMNs than ciprofloxacin and ofloxacin. It was concluded that trovafloxacin reaches concentrations within phagocytic and nonphagocytic cells several times higher than the extracellular ones, while it remains active in PMNs.
The decision before operation whether an esophagus affected by cancer can be resected is difficult. In order to determine if the tumor can be removed or not, patients must undergo surgery. This high risk intervention is often carried out only to prescribe palliative treatment. We used a thoracoscopic technique for the diagnosis and resection of esophageal cancer with the aim of improving the high morbidity rate associated with esophageal open surgery. A right thoracoscopy was performed in seven patients and only four underwent resection. The entire esophagus was mobilized thoracoscopically and the intervention was completed through the abdomen and the neck. In three patients in whom resection was not considered possible, the thoracoscopic procedure was done with excellent tolerance, and treated by palliative methods. Thoracoscopy is a very valuable procedure for the diagnosis of resectability as well as for the mobilization of the esophagus prior to resection.
OBJECTIVE: To evaluate our application of indications, use and benefits of conventional hemodialysis during surgery in patients with advanced liver disease and acute or chronic renal failure undergoing liver transplantation (LP), liver retransplantation (LRT) or combined hepatorenal transplantation (CHRT). PATIENTS AND METHODS: We retrospectively reviewed the cases of 22 patients with advanced liver disease, 11 with acute renal failure and 11 with chronic renal failure. We performed 6 LT, 5 LRT and 11 CHRT. The following data were recorded in the periods before, during and immediately after surgery: metabolic, hemodynamic and coagulation parameters; bicarbonate, calcium and inotropic drug requirements; incidences during reperfusion of the graft; surgical technique used; and survival. RESULTS: Seven patients (32%) needed hemodialysis, 4 (18%) needed ultrafiltration, 7 (32%) needed both and 4 (18%) required neither. For 6 patients total clamping of the inferior vena cava (ICV) was required with external venovenous bypass. For 8 patients total clamping of the IVC was performed without venovenous bypass. For 8 others IVC clamping was partial with retrohepatic preservation (piggy-back). There were 2 deaths during surgery, 4 more within the first month after surgery and 4 more in the second month. Overall survival was 36.4% among acute patients and 72.7% among CHRT patients. CONCLUSIONS: 1) Conventional hemodialysis during surgery is feasible and gives good results; 2) conventional "high efficiency" hemodialysis is more effective and useful in these patients than is either slow, continuous hemodialysis or filtration; 3) the survival rate of CHRT patients is similar to that of patients undergoing LT with normal kidney function, and 4) partial IVC clamping in the anhepatic phase may decrease the need for ultrafiltration.
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Pulmonary blastoma (PB) is a rare primary malignancy of the lung, with about 54 cases reported in children. The tumor consists of mesenchymal and epithelial components resembling the fetal lung. It has been treated primarily with surgery and the effect of combination chemotherapy has not been systematically investigated. A 15-year-old girl with PB with metastases to bone and regional lymph node, and high levels of alphafetoprotein, is reported. A preoperative combination chemotherapy consisting of cisplatinum, etoposide alternating with iphosphamide with mesna, vincristine and epirubicine resulted in an objective response that permitted subsequent safe surgical excision of the primary tumor. This intensive combination chemotherapy should be tested in the management of advanced PB in children, as initial therapy as well as an adjuvant to surgery.
We evaluated the effect of paclitaxel alone or in combination with cisplatin or doxorubicin, on the intracellular penetration and activity of ciprofloxacin, ofloxacin, levofloxacin and sparfloxacin in human polymorphonuclear leukocytes (PMN). In general, paclitaxel either alone or in combination did not affect the intracellular concentrations of the quinolones evaluated (intracellular to extracellular concentration ratio (C/E > 4). However, at high concentrations (20 mg/L) paclitaxel decreased the penetration of ofloxacin and levofloxacin although the C/E ratios remained higher than 3. Paclitaxel alone or in combination affected neither the production of oxygen radicals by PMN nor the intracellular activity of the quinolones against Staphylococcus aureus.
BACKGROUND: The intracellular penetration and activity of antimicrobial agents can be an important factor in the treatment of infections caused by intracellular pathogens. The new quinolones are able to penetrate into phagocytes, but only a few studies have evaluated other types of cells. The purpose of this study is to evaluate the intracellular penetration of ofloxacin, levofloxacin, lomefloxacin, sparfloxacin and BAY Y 3118 into human polymorphonuclear leukocytes and tissue cultured epithelial cells. METHODS: Intracellular penetration was evaluated by a fluorometric assay for all the quinolones evaluated except for sparfloxacin, which was evaluated by a radiometric assay. RESULTS: All the quinolones evaluated reached intracellular concentrations higher than extracellular ones. The penetration of sparfloxacin and BAY Y 3118 into the epithelial cells was similar to those observed for PMNs (cellular to extracellular concentration ratio; C/E > or = 4). The C/E values of ofloxacin, levofloxacin and lomefloxacin for epithelial cells were lower than those observed in PMN, but still yielding C/E values > or = 2.
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We report an insulin-treated diabetic patient who suffered, in a 2-month period, three severe anaphylactic reactions immediately after self-administered subcutaneous injections of neutral protamine Hagedorn (NPH) human recombinant-DNA insulin. These reactions consisted of local and systemic symptoms, including dyspnea and hypotension. A simultaneous sensitization to human insulin and to protamine was demonstrated, both by skin tests and by the determination of serum specific IgE. Suspecting protamine allergy, we performed a test dose to human lente insulin with perfect tolerance. After a 1-year follow-up with lente-insulin treatment, no reactions have occurred, despite treatment interruptions. Therefore, protamine IgE-mediated allergy probably caused our patient's reactions. In conclusion, protamine sensitization should be ruled out in any patient with a history of reactions to subcutaneous protamine-containing insulins, even if insulin sensitization is present.
BACKGROUND: A comparative evaluation of the intracellular penetration of norfloxacin, ofloxacin, levofloxacin, fleroxacin and lomefloxacin was carried out in human polymorphonuclear leucocytes (PMNs). METHODS: The fluorometric method was used based on the natural fluorescence of some fluoroquinolones. RESULTS: All the fluoroquinolones accumulated within the human polymorphonuclear leucocytes achieving a quotient of between 4 to 6 in intracellular and extracellular concentration (I/C) with no significant differences being observed between the two. Penetration was rapid and was not saturable within the intervals of extracellular concentrations tested. The intracellular penetration of these fluoroquinolones was dependent on temperature and cell viability was altered in only levofloxacin and norfloxacin. The I/E values obtained significantly decreased when the cells were incubated at 4 degrees C. These values showed an important increase to pH 5 and decreased to pH 9, with this pH being statistically significant only in ofloxacin. CONCLUSIONS: All the fluoroquinolones evaluated penetrated rapidly into the phagocytic cells achieving intracellular concentrations which were several fold higher than the extracellular concentrations, with no notable differences being observed being the two, thus providing an additional advantage for their use in infections produced by microorganisms capable of surviving intracellularly.
It has been evaluated the effect of norfloxacin, ofloxacin, levofloxacin, fleroxacin and lomefloxacin of the respiratory burst of human polymorphonuclear leukocytes and their intracellular activity against Staphylococcus aureus. None of these agents significantly affected the superoxide and hydrogen peroxide radicals production by the polymorphonuclear leukocytes. All the quinolones except norfloxacin showed significant intracellular activity against S. aureus.
We have studied the effect of blockade of mitochondrial respiration on the binding of human 125I-TNF alpha to L929 cell receptors. Specific TNF alpha binding was decreased to about 20-40% of controls by blocking mitochondrial respiration. This effect was dose- and time-related and was observed independently of the level at which the respiration was blocked (respiratory chain, proton backflow, ATPase, anaerobiosis). This blockade had no effect on the half-life of the specific TNF alpha binding, the internalization or degradation of TNF alpha-receptor complexes, or the number of TNF alpha-binding sites. Scatchard analysis of TNF alpha binding data indicated a 2-4-fold decrease in the affinity of these binding sites. These effects did not appear to be related to the protein kinase C activity or to reactive oxygen radicals, since they were not antagonized by pretreatment of cells with oxygen radical scavengers, deferoxamine, or inhibitors of protein kinase C. Decrease in TNF alpha binding capacity correlated significantly with cellular ATP content (r = 0.94; p < 0.01) and with the cytocidal activity of TNF alpha against L929 cells. These findings suggest that blockade of mitochondrial respiration down-regulates the binding of TNF alpha to cells, most likely by changing the affinity of receptors for this cytokine. This down-regulation may increase the resistance of cells to TNF alpha cytotoxicity.
Previous studies have implicated the bcl-2 protooncogene as a potential regulator of neuronal survival. However, mice lacking functional bcl-2 exhibited normal development and maintenance of the central nervous system (CNS). Since bcl-2 appears dispensable for neuronal survival, we have examined the expression and function of bcl-x, another member of the bcl-2 family of death regulatory genes. Bcl-2 is expressed in neuronal tissues during embryonic development but is down-regulated in the adult CNS. In contrast, Bcl-xL expression is retained in neurons of the adult CNS. Two different forms of bcl-x mRNA and their corresponding products, Bcl-xL and Bcl-x beta, were expressed in embryonic and adult neurons of the CNS. Microinjection of bcl-xL and bcl-x beta cDNAs into primary sympathetic neurons inhibited their death induced by nerve growth factor withdrawal. Thus, Bcl-x proteins appear to play an important role in the regulation of neuronal survival in the adult CNS.
A gene (chit33) from the mycoparasitic fungus Trichoderma harzianum, coding for a chitinase of 33 kDa, has been isolated and characterized. Partial amino-acid sequences from the purified 33-kDa chitinase were obtained. The amino-terminal peptide sequence was employed to design an oligonucleotide probe and was used as a primer to isolate a 1.2-kb cDNA. The cDNA codes for a protein of 321 amino acids, which includes a putative signal peptide of 19 amino acids. All microsequenced peptides found in this sequence, indicate that this cDNA codes for the 33-kDa chitinase. A high homology (approximately 43% identity) was found with fungal and plant chitinases, including yeast chitinases. However enzyme characteristics suggest a nutritional (saprophytic or mycoparasitic), rather than a morphogenetic, role for this chitinase. The chit33 gene appears as a single copy in the T. harzianum genome, is strongly suppressed by glucose, and de-repressed under starvation conditions as well as in the presence of autoclaved mycelia and/or fungal cell walls. The 33-kDa chitinase seems to be very stable except under starvation conditions. The independent regulation of each of the chitinases in T. harzianum indicates different specific roles.
Azithromycin is a new macrolide which accumulates in high concentrations in human phagocytes. The cellular to extracellular ratio (C/E) of azithromycin concentrations (fixed extracellular concentration 1 mg/L) in human polymorphonuclear leucocytes (PMN) were significantly affected by small increases in the environmental temperature (C/E 20.3 +/- 2 and 59.4 +/- 6 at 37 degrees C and 40 degrees C, respectively). PMN-associated azithromycin was not affected by the presence of different concentrations of human serum. The intracellular accumulation of azithromycin decreased slightly (C/E approximately 5) when cells were activated with PMA or opsonized with zymosan. The phagocytosis of opsonized Staphylococcus aureus or Haemophilus influenzae, however, slightly increased the intracellular concentrations of azithromycin. At different extracellular concentrations, azithromycin did not affect the production of hydrogen peroxide and superoxide radicals by PMN. The intracellular survival of H. influenzae in human PMN was abolished in the presence of concentrations higher than 0.125 mg/L of azithromycin. Under the same experimental conditions, however, azithromycin did not show any intracellular activity against S. aureus.
The activity of sparfloxacin on Staphylococcus epidermidis biofilms on different plastic catheters was evaluated. Sparfloxacin showed high bactericidal activity against S. epidermidis biofilms on Vialon and polyvinylchloride catheters. The combination of sparfloxacin with amikacin or rifampicin significantly increased its activity against bacterial biofilms on polyurethane and Teflon catheters.
OBJECTIVE: Donors age 50 years was an exclusion criteria in past decades. The increase of patients in the waiting list has determined the acceptance of older donors (over 65 years old). We analyze our results in liver transplantation using donors over 65 years. PATIENTS: From 1986 to may 1994, we performed 381 OLT. In five cases (1.3%) the OLT was performed using donors over 65 years of age (66, 67, 68, 70 and 71). The selection criteria for donors and recipients were similar to the other transplanted patients. Immunosuppression included cyclosporine or FK-506, prednisone and azathioprine. RESULTS: There were no primary graft failures and preservation damage, biochemical and clinical evolution were not different to the procedures using younger donors. Three grafts presented non-corticoresistant acute rejection. After a follow-up of 11.6 mo (range 4-37 mo) only one graft was lost (Kaposi's sarcoma in the liver). Four grafts and four patients are in excellent biochemical and clinical condition. CONCLUSIONS: Donor age should not be an exclusion criteria. Grafts from older donors (over 65 years old) may be considered safe and will permit to increase the number of OLT.