N-(5,5-diacetoxypent-1-yl)doxorubicin: a new intensely potent doxorubicin analog

N-(5,5-Diacetoxypent-1-yl)doxorubicin (DAPDOX) (3), a new, water-soluble analogue of doxorubicin, has been synthesized by coupling doxorubicin with 5-oxopentane-1,1-diacetate in the presence of NaBH3CN. This analogue was designed to be converted to the corresponding aldehyde, N-(5-oxopent-1-yl)doxorubicin, in the presence of carboxylate hydrolases, enzymes that are ubiquitous in tissue. DAPDOX had a half-life of several days in 0.05 M phosphate or 0.05 M acetate buffer solution at pH 4.0. However, in 0.05 M phosphate buffer at pH 7.4 in the presence of 20 unit equiv of porcine liver carboxylate esterase, the half-life of DAPDOX was less than 1 min. N-(5-acetoxypent-1-yl)doxorubicin (4), which should give rise to N-(5-hydroxypent-1-yl)doxorubicin on esterase-mediated hydrolysis, and N-(pent-1-yl)doxorubicin (5), were also prepared for comparative biological studies. DAPDOX was 150 times more potent than doxorubicin at inhibiting the growth of Chinese hamster ovary (CHO) cells in culture. The compound retained the same degree of potency against a CHO subline 100-fold resistant to doxorubicin (CHO/DOX) that expressed elevated levels of P-glycoprotein. Compounds 4 and 5, on the other hand, were no more effective than doxorubicin at inhibiting the growth of CHO cells and were 4-7-fold less potent against the CHO/DOX subline. DAPDOX is representative of a new structural class of doxorubicin analogues with unique chemical and biological properties.

Microbial characterization during composting of municipal solid waste

This study investigates the prevailing physico-chemical conditions and microbial community; mesophilic bacteria, yeasts and filamentous fungi, bacterial spores, Salmonella and Shigella as well as faecal indicator bacteria: total coliforms, faecal coliforms and faecal Streptococci, present in a compost of municipal solid waste. Investigations were conducted in a semi-industrial pilot plant using a moderate aeration during the composting process. Our results showed that: (i) auto-sterilization induced by relatively high temperatures (60-55 degrees C) caused a significant change in bacterial communities. For instance, Escherichia coli and faecal Streptococci populations decreased, respectively, from 2 x 10(7) to 3.1 x 10(3) and 10(7) to 1.5 x 10(3) cells/g waste dry weight (WDW); yeasts and filamentous fungi decreased from 4.5 x 10(6) to 2.6 x 10(3) cells/g WDW and mesophilic bacteria were reduced from 5.8 x 10(9) to 1.8 x 10(7) bacteria/g WDW. On the other hand, the number of bacterial spores increased at the beginning of the composting process, but after the third week their number decreased notably; (ii) Salmonella disappeared completely from compost by the 25th day as soon as the temperature reached 60 degrees C; and (iii) the bacterial population increased gradually during the cooling phase. While Staphylococci seemed to be the dominant bacteria during the mesophilic phase and at the beginning of the thermophilic phase, bacilli predominated during the remainder of the composting cycle. The appearance of gram-negative rods (opportunistic pathogens) during the cooling phase may represent a serious risk for the sanitary quality of the finished product intended for agronomic reuse. Compost sonication for about 3 min induced the inactivation of delicate bacteria, in particular gram-negatives. By contrast, gram-positive bacteria, especially micrococcus, spores of bacilli, and fungal propagules survived, and reached high concentrations in the compost.

[Severe pulmonary hypertension in ostium secundum atrial septal defect]

Between 1969 and 1999, 149 patients underwent cardiac catheterization for ostium secundum atrial septal defect, in hemodynamics department. Age average was 21.5 +/- 16 years (2-67). Systolic pulmonary arterial pressure average was 35 +/- 15.6 mm Hg (15-140). The atrial septal defect was closed in 108 patients (by surgery in 107 cases, and by interventional catheterization in one case). Mean follow-up was 8 +/- 7 years (1-20). Overall mortality rate was 2.7%. Severe pulmonary hypertension (systolic pressure > or = to 50 mm Hg) was seen in 13.4% of cases. It was present at all ages, but more frequent above 20 years. Obstructive pulmonary vascular disease was noticed in 2% of patients. Clinical and haemodynamic data analysis showed that, severe pulmonary hypertension is a frequent, and unpredictible complication of secundum atrial septal defect; it might occur at any age and worsen considerably the cardiac disease prognosis. Because of atrial septal defect hemodynamic profile, and current rise of percutaneous closure technics, invasive investigation should be more and more routinely performed, in order to define the best therapeutic option. Early and systematic closure of secundum atrial septal defects, should prevent, or at least minimize pulmonary vascular lesions.

[Coronary artery disease in Takayasu's disease. Report of an operative case]

A 39-years-old woman with Takayasu's arteritis confirmed by histological examination was admitted in our hospital because of angina pectoris. Selective coronary arteriograms reveled a 90% isolated stenosis in the right coronary ostium. The patient underwent a right coronary artery bypass grafting using the saphenious vein. The post operative clinical course was uncomplicated. On follow-up over 14 months the patient has been completely free from anginal chest-pain.

Thuricin 7: a novel bacteriocin produced by Bacillus thuringiensis BMG1.7, a new strain isolated from soil

AIMS

Detection and identification of new antagonistic activities towards Bacillus cereus and relatives.

METHODS AND RESULTS

Twenty Bacillus thuringiensis strains were screened for their capacity to express bacteriocin-like agents. Strain BMG1.7, isolated from soil, showed an antagonistic activity called thuricin 7. Thuricin 7 was active against several species of the genus Bacillus, including three of the four known B. thuringiensis/B. cereus bacteriocin producers, as well as against Streptococcus pyogenes and Listeria monocytogenes strains. Antimicrobial activity was lost after treatment with proteinase K. The active protein had an apparent molecular weight of 11.6 kDa, and was secreted at the end of the exponential growth phase. Thuricin 7 retained 55% of the activity after incubation at 98 degrees C for 30 min. The mode of action of thuricin 7 was shown to be bactericidal and bacteriolytic.

CONCLUSION

Thuricin 7 is a novel bacteriocin produced by a newly isolated Bacillus thuringiensis strain BMG1.7.

SIGNIFICANCE AND IMPACT OF THE STUDY

The characteristics of thuricin 7 indicate that it is a new bacteriocin which may have interesting biotechnological applications due to its relatively large activity spectrum.

Thuricin 7: a novel bacteriocin produced by Bacillus thuringiensis BMG1.7, a new strain isolated from soil

AIMS

Detection and identification of new antagonistic activities towards Bacillus cereus and relatives.

METHODS AND RESULTS

Twenty Bacillus thuringiensis strains were screened for their capacity to express bacteriocin-like agents. Strain BMG1.7, isolated from soil, showed an antagonistic activity called thuricin 7. Thuricin 7 was active against several species of the genus Bacillus, including three of the four known B. thuringiensis/B. cereus bacteriocin producers, as well as against Streptococcus pyogenes and Listeria monocytogenes strains. Antimicrobial activity was lost after treatment with proteinase K. The active protein had an apparent molecular weight of 11.6 kDa, and was secreted at the end of the exponential growth phase. Thuricin 7 retained 55% of the activity after incubation at 98 degrees C for 30 min. The mode of action of thuricin 7 was shown to be bactericidal and bacteriolytic.

CONCLUSION

Thuricin 7 is a novel bacteriocin produced by a newly isolated Bacillus thuringiensis strain BMG1.7.

SIGNIFICANCE AND IMPACT OF THE STUDY

The characteristics of thuricin 7 indicate that it is a new bacteriocin which may have interesting biotechnological applications due to its relatively large activity spectrum.

Heterogeneity among infecting strains of Pseudomonas aeruginosa in diverse departments of a large Tunisian hospital

Clinical isolates of Pseudomonas aeruginosa were obtained during a half-year screening period of five different wards of the La Rabta Hospital (Tunis). Distinct clinical isolates (N= 82) were obtained from patients, 40 (48%) of which originated from the Department of Otolaryngology. In order to define the local epidemiology of this opportunistic organism, all strains were serotyped, analysed for pyocin production and genetically characterized with the help of pulsed-field gel electrophoresis (PFGE). The data show that, despite the frequent occurrence of identical serotypes, most of the isolates represent unique pyocin types (N= 53) and genotypes (N= 64). A combination of the pyocin and PFGE data showed that nearly all strains were of unique types, except for two pairs of strains. A limited number of strain clusters was observed on the basis of DNA typing data alone. This involved eight genotypes, some of which were clustered with respect to clinical environment or time. Genotype 22 occurred most frequently (6/83, 7%) and independently of time and locale, indicating that it may represent either a clonal type constituting a major fraction of all P. aeruginosa isolates in the region or a more prevalent organism. Despite a relatively high incidence of P. aeruginosa infections, the polyclonality of these strains shows that, in La Rabta Hospital, pseudomonal infections are not primarily due to excessive spread of a single bacterial genotype.

Homoduplex and heteroduplex polymorphisms of the amplified ribosomal 16S-23S internal transcribed spacers describe genetic relationships in the "Bacillus cereus group"

Bacillus anthracis, Bacillus cereus, Bacillus mycoides, Bacillus pseudomycoides, Bacillus thuringiensis, and Bacillus weihenstephanensis are closely related in phenotype and genotype, and their genetic relationship is still open to debate. The present work uses amplified 16S-23S internal transcribed spacers (ITS) to discriminate between the strains and species and to describe the genetic relationships within the "B. cereus group," advantage being taken of homoduplex-heteroduplex polymorphisms (HHP) resolved by polyacrylamide gel electrophoresis and silver staining. One hundred forty-one strains belonging to the six species were investigated, and 73 ITS-HHP pattern types were distinguished by MDE, a polyacrylamide matrix specifically designed to resolve heteroduplex and single-strand conformation polymorphisms. The discriminating bands were confirmed as ITS by Southern hybridization, and the homoduplex or heteroduplex nature was identified by single-stranded DNA mung bean nuclease digestion. Several of the ITS-HHP types corresponded to specific phenotypes such as B. anthracis or serotypes of B. thuringiensis. Unweighted pair group method arithmetic average cluster analysis revealed two main groups. One included B. mycoides, B. weihenstephanensis, and B. pseudomycoides. The second included B. cereus and B. thuringiensis, B. anthracis appeared as a lineage of B. cereus.

[Study of the incidence and cost of nosocomial infections in general surgery]

Nosocomial infection incidence and its cost were study. We have identified 61 infected patients and 75 infectious episodes, is an incidence of 9.4% infected for 100 hospitalized by trimester. Operative site infections are the most frequent (60%), operative site infection (9.1%), inferior respiratory ways infections (2.2%). Incriminated germs are represented essentially by negative gram Bacillus (77.3%) with predominance of enterobacterias (59%). Invasive technique usage, surgery types and contamination classes have been identified as risk factors of nosocomial infection occurrence. The supplementary stay duration estimated by simple comparison between infected group and no-infected one is 9.3% days, responsible of an over cost of 336 TD by infected patient and 273 TD by infectious episode. The curative antibiotic costs have been estimated at 70 TD by infected patient being equivalent to two hospitalization days and to 57 TD by infectious episode.

[Evolution after 5 years of percutaneous pulmonary valvulotomy: report of 47 cases]

47 patients aged from 2 to 59 years affected by valvular congenital or mixed pulmonary stenosis including three fallot trilogies and one patient with right congestive cardiac failure are treated by percutaneous pulmonary valvulotomy between october 1986 and december 1990. All patients have been controlled with a mean follow-up of 6.5 +/- 1.1 years. The total gradient rate between pulmonary artery and right ventricule decrease from 112 +/- 55 mm Hg to 20 +/- 8 mm Hg on the last control with disappearance of infundibular inflammation and inter auricular shunt in all the concerned cases. We observe the regression of right cardiac failure symptoms with disappearance of tricuspid insufficiency in the cases of advanced pulmonary stenosis with right ventricular dysfunction. Percutaneous pulmonary valvulotomy by its simplicity and harmlessness, its long term efficiency is a good method of treatment of pure valvular or mixed pulmonary stenosis.

Intensely potent doxorubicin analogues: structure-activity relationship

N-(5,5-Diacetoxypent-1-yl)doxorubicin (1b) is an intensely cytotoxic doxorubicin analogue that retains full potency against tumor cells that express elevated levels of P-glycoprotein and are resistant to doxorubicin. 1b was designed to be hydrolyzed in the presence of carboxylate esterases to N-(5-oxypent-1-yl)doxorubicin, an aldehyde capable of existing in equilibrium with a cyclic carbinolamine. To investigate the structural determinants of potency for 1b, we have prepared a series of chemically related compounds in which various omega-[bis(acetoxy)]alkyl or omega-[bis(acetoxy)]alkoxyalkyl groups are substituted at the 3'-amino position of the daunosamine sugar. These groups were selected to assess the effect of chain length, oxygen substitution, and carbinolamine ring size on analogue potency. The compounds were evaluated for their ability to inhibit the in vitro growth of the following cell lines: (a) Chinese hamster ovary (CHO) cells, (b) a CHO cell mutant 100-fold resistant to doxorubicin that expresses elevated levels of P-glycoprotein, (c) a murine ductal cell pancreatic adenocarcinoma (Panc 02), and (d) a murine mammary carcinoma (CA 755). The most potent members of the series were those that could form a straight chain aldehyde intermediate after esterase-mediated hydrolysis of the omega-bis(acetoxy) groups and give rise to 5- or 6-membered ring carbinolamines. Analogues capable of forming 7-, 8-, or 9-membered carbinolamines were markedly less active. The N-methyl derivative of 1b, which cannot give rise to a cyclic carbinolamine, was 2 orders of magnitude less potent than 1b. A branched chain analogue, 1f, which contained a tertiary carbon atom adjacent to the omega-bis(acetoxy) groups, was also substantially less active than its nonbranched counterpart, 1a. These findings suggest that the chain length of the 3'-amino substituents and the ability of the derived aldehydes to form 5- or 6-membered carbinolamines are critical determinants of biologic potency.

Cadmium- and copper-induced changes in tomato membrane lipids

Cadmium and copper uptake and distribution, as well as their effects on growth and lipid composition were investigated in 17-day-old tomato seedlings (Lycopersicon esculentum Mill. cv. 63/5 F1) grown in culture solution supplied with two concentrations of Cd or Cu (0, 5 and 50 microM). The accumulation of Cd and Cu increased with external metal concentrations, and was considerably higher in roots than in primary leaves. Biomass production of the growing roots and primary leaves was strongly depressed at high metal levels. Also, significant decreases in the content of lipid classes and changes of fatty acid composition were recorded in heavy metal-stressed plants in comparison with controls. Glycolipid contents were decreased more in leaves than in roots by Cd-treatment, but copper decreased both to similar extents in both organs. Likewise, both metals reduced the phospholipid and neutral lipid contents more in roots than in leaves. In almost all lipid classes the proportion of palmitic acid (16:0) increased, and that of linoleic (18:2) or linolenic (18:3) acid decreased, suggesting that heavy metal treatment induced an alteration in the fatty acid desaturation processes. Furthermore, the accumulation of palmitate (16:0) rather than stearate (18:0) indicated an alteration in the ratio of products from the fatty acid synthase. Copper was found to be the most unfavourable for plant growth and lipid metabolism. The possible mechanisms by which heavy metals, especially Cu, induce a strong lipid shift are discussed.

Evaluation of [131I]iodoerythronitroimidazole as a predictor for the radiosensitizing effect

The aim of this study was to evaluate whether radiolabeled iodoerythronitroimidazole (IETNIM) could predict the radiosensitization effect on tumors. Tumor-bearing mice were irradiated at a dose of 25, 31 and 37 Gy after the injection of IETNIM. They were also exposed to 37 Gy radiation at 35, 70, 140 and 240 min after the i.p. injection of IETNIM. After the irradiation, tumor growth assays were conducted and the effect of IETNIM as a radiosensitizer was estimated as enhancement factor (EF). Tumor uptake was measured at 35, 70, 140 and 240 min after i.p. injection of [131I]IETNIM, which were the same intervals used in the radiosensitization study. EF of IETNIM in mice treated with 25, 30 and 37 Gy irradiation was 0.72, 0.98 and 1.28, respectively. EF of IETNIM in mice irradiated at 35, 70, 140 and 240 min after the injection was 1.50, 1.69, 1.46 and 1.08, which corresponded to the tumor uptake and blood clearance of [131I]IETNIM. [131I]IETNIM may be a suitable radiopharmaceutical to predict the radiosensitization effect of misonidazole analogs on tumors.

Positron emission tomography using [18F]fluorotamoxifen to evaluate therapeutic responses in patients with breast cancer: preliminary study

Positron emission tomography (PET) was used to assess the biodistribution and clinical usefulness of [18F]fluorotamoxifen (FTX) in 10 patients with estrogen-receptor(ER)-positive breast tumors. Ten patients with ER-positive breast cancer were prospectively studied, and the consecutive PET imagings (each takes 15 or 20 min) were obtained for 60 or 80 min after the injection of 88.8-392.2 MBq (2.4-10.6 mCi) of [18F]FTX. Twenty three suspected primary or metastatic lesions in 10 patients were evaluated and the tumor uptakes of [18F]FTX in nineteen tumor lesions were correlated to the response of tamoxifen therapy. Three lesions in three patients were considered to be truly negative for breast cancer on the bases of biopsy specimens and/or clinical course. Five (71.4%) of seven patients and 16 (80.0%) of 20 lesions were interpreted to be truly positive for breast cancer. The mean standardized uptake value (SUV) of the radiotracer in tumor was 3.0 on delayed images. There was no significant correlation between the standardized uptake values of [18F]FTX and the ER concentrations in primary lesions. Nineteen tumor lesions in six patients were evaluable to compare the [18F]FTX uptake with responses to tamoxifen therapy after the PET study. Three patients who had a good response to tamoxifen therapy showed positive lesions on PET images, whereas two of three patients who had a poor response showed negative lesions and one showed mixed results. There was no significant difference of [18F]FTX uptake in bone lesions between good and poor responders. However, when bone lesions were excluded, [18F]FTX uptakes in tumors with good responses were significantly higher than those with poor responses (mean and standard deviation of SUV: 2.46 +/- 0.62 vs 1.37 +/- 0.59, P < 0.05). PET imaging using [18F]FTX provides useful information in predicting the effect of tamoxifen therapy in patients with ER-positive breast cancer. Further study is warranted to confirm the clinical utility of PET using [18F]FTX in breast cancer patients.

Synthesis, biodistribution, and estrogen receptor scintigraphy of indium-111-diethylenetriaminepentaacetic acid-tamoxifen analogue

This study was aimed at developing a hydrophilic diethylenetriaminepentaacetic acid-tamoxifen (DTPA-Tam) analogue for use in imaging estrogen receptor positive (ER+) lesions. In rat uterine cytosol, the IC50 of DTPA-Tam conjugate was 1 microM and of tamoxifen, 2 microM. Biodistribution, autoradiography, and radionuclide imaging of 111In-DTPA-Tam in breast-tumor-bearing rats showed that tumor-to-tissue ratios increased steadily between 30 min and 48 h. The in vivo response of MCF-7 breast cancer xenografts to tamoxifen and DTPA-Tam in nude mice demonstrated that DTPA-Tam could reduce tumor growth rate. These results indicate that DTPA-Tam, a new hydrophilic ER+ ligand, might be useful in diagnosing ER+ lesions.

[Complications of percutaneous mitral commissurotomy. Personal experience and review of the literature]

Percutaneous mitral commissurotomy was performed in 484 patients by the double balloon technique and by Inoue's technique in 33 patients. The average age of the patients was 33.6 +/- 13 years (range: 8 to 72 years); 30% were in atrial fibrillation. A primary failure was observed in 10 patients (2%). The acute mortality was 0.4% and first month mortality 0.6%, the main cause being perforation of the left ventricle. The incidence of systemic embolism was 2%, related to atrial fibrillation (p < 0.016); this complication disappeared after systematic utilisation of transoesophageal echocardiography. Grade 4+ mitral regurgitation was created in 5 patients (1%) and grade 3+ in 20 others (3.9%). A score > 8 (p < 0.006) and preexisting grade 1+ mitral regurgitation (p < 0.005) were predictive factors of these severe regurgitations. They were also more frequent with Inoue's technique (10.5%; p < 0.05). Surgical intervention was necessary during the first month in 5 patients and at long-term (38 +/- 24 months) in 15 others. A tear in the anterior leaflet and ruptured chordae tendinae were the main mechanisms. The most common minor complication was the creation of a small interatrial shunt (16%) without any immediate or long-term complications. With a major complication rate of 4.2%, the mitral surface area increased from 0.97 to 2.2 cm2 and the cardiac index from 3 to 3.6 l/min/m2; left atrial pressure fell from 27 to 15 mmHg (p < 0.0001): the incidence of residual stenosis was only 2%. Seventy nine per cent of patients were asymptomatic and 16% were paucisymptomatic (class II) at long-term. Systematic transoesophageal echocardiography to detect thrombi, the use of pig-tail or Inoue catherters, effective heparinisation during a prolonged procedure and improved experience of the medical teams, should result in a further reduction of the risks of percutaneous mitral commissurotomy.

Assessment of tumor cell proliferation using [18F]fluorodeoxyadenosine and[18F]fluoroethyluracil

This study was to develop radiofluorinated ethyluracil (FEU) and deoxyadenosine analogues (FAD) for noninvasive assessment of tumor proliferative potential by positron emission tomography (PET). 5-(2-Fluoroethyl)uracil ([18F]FEU) was prepared by treating 2,4-dimethoxy-5-(2-hydroxyethyl)pyrimidine with K18F, followed by hydrolysis with HBr. Fluorodeoxyadenosine ([18F]FAD) was prepared by treating a triacetylated analogue of adenosine with K18F. In vitro cell proliferation assay of [18F]-FEU was performed using human peripheral blood mononucleus cells. Tissue distributions were studied in breast tumor-bearing rats at 0.5, 1, 2 and 4 h along with autoradiography at 45 min postinjection. PET imaging studies were conducted in VX-2 tumor-bearing rabbits. In vitro assay indicated that [18F]FEU incorporated into DNA/RNA during cell proliferation. Tumor-to-tissue count density ratios of [18F]FAD and [18F]-FEU increased as a function of time. [18F]FAD had higher tumor-to-nontumor tissue count density ratios than [18F]FEU. Autoradiograms of [18F]FEU and [18F]FAD, and PET images of [18F]FEU, showed that the tumors could be well visualized. The results suggest that [18F]FEU and [18F]FAD have potential use in evaluating tumor cell proliferation by PET.

Development of new markers for hypoxic cells: [131I]Iodomisonidazole and [131I]Iodoerythronitroimidazole

This study was aimed at developing ligands to evaluate tumor hypoxia by planar scintigraphy. Two 2-nitroimidazole analogues were developed as precursor compounds to image hypoxic tumors. Both tosylmisonidazole (Ts MISO) and tosylerythronitroimidazole (Ts ETNIM) were labeled with 131I. The biodistribution and autoradiographic evaluations by planar scintigraphy of 131I-IMISO and 131I-IETNIM were conducted at 1, 2 and 4 hours after administration to rats bearing 13762 breast tumors. Biodistribution of 131I-IMISO was also evaluated in Madison lung tumor-bearing mice. Intratumoral oxygen tension was measured by the Eppendorf system. Biodistribution showed similar tumor/blood and tumor/muscle count density ratios for both compounds. The thyroid uptake of both analogues was increased with time, suggesting in vivo deiodination probably occurred. Autoradiographs of 131I-IMISO and 131I-IETNIM revealed good visualization of the neoplasms. The tumor oxygen tension was 3-6 mmHg as compared to the normal tissue oxygenation of 30-40 mmHg. The findings indicate that these analogues can localize in the hypoxic region of solid tumors and may assist with quantitation of the hypoxic fraction of tumor for proper selection and evaluation of appropriate radiotherapy and chemotherapy.

Results of percutaneous double-balloon mitral commissurotomy in one medical center in Tunisia

Percutaneous balloon mitral commissurotomy was attempted in Tunisia, where rheumatic fever is still endemic, in 463 consecutive patients with severe rheumatic mitral valve stenosis. Their mean age +/- SD was 33 +/- 12 years (range 8 to 68), 324 patients (70%) were women, and 327 (71%) were in sinus rhythm. Valvotomy was technically successful in 454 patients (98%). The mean mitral valve gradient decreased from 20 +/- 7 to 6 +/- 4 mm Hg, mean left atrial pressure decreased from 27 +/- 8 to 15 +/- 6 mm Hg, cardiac index increased from 3.0 +/- 0.7 to 3.6 +/- 0.8 L/min/m2, and Gorlin mitral valve area, from 0.97 +/- 0.19 to 2.2 +/- 0.4 cm2 (all p < 0.001). Two-dimensional echocardiographic mitral valve area increased from 1.03 +/- 0.18 to 2.15 +/- 0.36 cm2 (p < 0.00001). A final valve area of > or = 1.5 cm2 was achieved in 98% of patients. Multivariate analysis identified a pre-mitral valve area < 0.8 cm2 and an echocardiographic score (echo score) > or = 12 as the strongest predictors of residual stenosis (final mitral valve area < 1.5 cm2). Major procedural complications included mortality (0.4%), tamponade (0.7%), thromboembolism (2.0%), severe mitral regurgitation (4.6%), significant (pulmonary to systemic flow ratio > or = 1.5) interatrial shunt (4.8%). Four hundred thirty patients were followed up between 6 and 82 months (mean 37 +/- 22): 95% were in functional class I to II without reintervention, and 7 patients died (1.6%); restenosis (echocardiographic mitral valve area < 1.5 cm2) occurred in 10.4% of patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Development of F-18-labeled fluoroerythronitroimidazole as a PET agent for imaging tumor hypoxia

PURPOSE

To develop a hydrophilic ligand to image tumor hypoxia at positron emission tomography (PET).

MATERIALS AND METHODS

Biodistribution of fluorine-18-labeled fluoroerythronitroimidazole (FETNIM) and F-18-labeled fluoromisonidazole (FMISO) was determined at PET and autoradiography in three mammary-tumor-bearing rats. The partition coefficient of FETNIM, FMISO, and misonidazole was determined.

RESULTS

Biodistribution of F-18-labeled FETNIM at 1, 2, and 4 hours showed tumor-to-blood ratios of 2.29 +/- 0.599, 2.41 +/- 0.567 and 8.02 +/- 2.420, respectively, and tumor-to-muscle ratios of 0.66 +/- 0.267, 2.11 +/- 0.347, and 5.92 +/- 2.240, respectively. The tumor-to-blood count density ratio with F-18-labeled FETNIM at 4 hours after injection was significantly higher than with F-18-labeled FMISO. Autoradiographs indicated that both agents could help differentiate hypoxic versus necrotic region in the tumor.

CONCLUSION

F-18-labeled FETNIM can help detect tumor hypoxia and is easier to prepare, less costly, and more hydrophilic than F-18-labeled FMISO.

Imaging, biodistribution and therapy potential of halogenated tamoxifen analogues

Tamoxifen binds to estrogen receptors (ERs) and prevents breast cancer cell proliferation. This study is aimed at developing a ligand for imaging ER (+) breast tumors by positron emission tomography (PET) or single photon emission computed tomography (SPECT). [18F]-Labeled tamoxifen analogue ([18F]FTX) was prepared in 30-40% yield and [131I]-labeled tamoxifen analogue ([131I]ITX) was prepared in 20-25% yield. In mammary tumor-bearing rats, the biodistribution of [18F]FTX at 2 h showed a tumor uptake value (% injected dose/gram tissue) of 0.41 +/- 0.07; when rats were pretreated with diethylstilbestrol (DES), the value changed to 0.24 +/- 0.017. [131I]ITX at 6 h showed a tumor uptake value of 0.26 +/- 0.166; when rats were pretreated with DES, the value changed to 0.22 +/- 0.044. Priming tumor-bearing rats with estradiol, a tumor uptake value for [131I]ITX was increased to 0.48 +/- 0.107 at 6 h. In the [3H]estradiol receptor assay, tumors had a mean estrogen receptor density of 7.5 fmol/mg of protein. In gamma scintigraphic imaging studies with [131I]ITX, the rabbit uterus uptake can be blocked by pretreatment with DES. Both iodo-tamoxifen and tamoxifen reduced ER(+) breast tumor growth at the dose of 50 micrograms in tumor-bearing mice. The findings indicate that tamoxifen analogue uptake in tumors occurs via an ER-mediated process. Both analogues should have potential for diagnosing functioning ER(+) breast cancer.

Synthesis of [18F]fluoroalanine and [18F]fluorotamoxifen for imaging breast tumors

To develop ligands for imaging breast tumors, [18F]fluoro analogue of tamoxifen and [18F]fluoroalanine were radiosynthesized. In vivo biodistribution studies were performed in mammary tumor-bearing rats. In studies on the biodistribution of an [18F]fluoro analogue of tamoxifen, tumor uptake decreased when rats were pretreated with diethylstilbestrol (DES), suggesting that tracer uptake in tumors was receptor-mediated. An estrogen receptor assay indicated that tumors have a receptor density of 7.5 fmol/mg protein. Studies of the distribution of [18F]fluoroalanine in tissue showed that the tumor-to-tissue ratio increases as a function of time. Positron emission tomography (PET) images of tumor-bearing rats demonstrated that tumors can be visualized 1 h after rats are injected with an [18F]fluoro analogue of tamoxifen. PET imaging of pigs after injection of 10 mCi of [18F]fluoro analogue of tamoxifen showed uterine uptake that could be blocked by DES (50 mg). The findings suggest that both radiotracers are useful for imaging breast tumors.

Halogenated analogues of tamoxifen: synthesis, receptor assay, and inhibition of MCF7 cells

This study was conducted to develop a ligand for imaging estrogen-receptor-positive breast tumors by positron emission tomography or single photon emission computed tomography. We synthesized fluoro and iodo analogues of tamoxifen, and these halogenated analogues produced greater affinity for binding to the receptor than tamoxifen. Values of the inhibition affinity constants were as follows: tamoxifen, 15,000 nM; fluoromethyl-N,N-diethyltamoxifen, 2500 nM for the cis isomer and 500 nM for the trans isomer; and iodomethyl-N,N-diethyltamoxifen, 1500 nM for the cis isomer and 1000 nM for the trans isomer. In studies of human MCF7 breast tumor cell growth, concentrations that inhibited tumor growth in 50% of the cases were as follows: tamoxifen, 11 microM; fluoromethyl-N,N-diethyltamoxifen, 4.5 and 11.8 microM for the cis and trans isomers, respectively; and iodomethyl-N,N-diethyltamoxifen, 2.4 and 6.3 microM for the cis and trans isomers, respectively. These studies suggest that both fluoro and iodo analogues of tamoxifen may be useful diagnostic compounds for predicting the response of estrogen-receptor-positive breast tumors to tamoxifen analogues used in chemotherapy.

Continuous positive airway pressure (CPAP) vs. intermittent mandatory pressure release ventilation (IMPRV) in patients with acute respiratory failure

Intermittent Mandatory Pressure Release Ventilation (IMPRV) is a positive pressure spontaneous breathing ventilatory mode in which airway pressure is released intermittently and synchronously with patient's spontaneous expiration in order to provide ventilatory assistance. Eight critically ill patients free of any factor known to alter chest wall mechanics (group 1) and 8 critically ill patients whose spontaneous respiratory activity was markedly altered by a flail chest, or by a C5 quadraplegia and/or by the administration of opioids (group 2) were studied prospectively. CPAP and IMPRV were administered to each patient in a random order during a 1 h period using a CESAR ventilator. Gas flow, tidal volume, tracheal pressure, esophageal pressure, end-expiratory lung volume and hemodynamic parameters were measured. In group 1 patients, the ventilatory assistance provided by IMPRV was associated with a significant decrease in spontaneous tidal volume whereas all other respiratory parameters remained unchanged. In group 2 patients, IMPRV increased minute ventilation from 8.0 +/- 2.61/min to 12.2 +/- 1.81/min (p less than 0.05), decreased PaCO2 from 46 +/- 7.3 mmHg to 38 +/- 6.8 mmHg (p less than 0.05) and reduced respiratory frequency from 21 +/- 10 bpm to 14 +/- 5.7 bpm (p less than 0.07). These results show that IMPRV provides significant ventilatory assistance to patients with mild acute respiratory failure either by decreasing patient's contribution to minute ventilation or by increasing alveolar ventilation in presence of respiratory depression of central or peripheral origin.

N-(5,5-diacetoxypentyl)doxorubicin: a novel anthracycline producing DNA interstrand cross-linking and rapid endonucleolytic cleavage in human leukemia cells

The cytotoxic and DNA-damaging effects of a novel alkylating anthracycline, N-(5,5-diacetoxypentyl)doxorubicin, were quantified in HL-60 human leukemia cells and in an intercalator-resistant daughter line, HL-60/AMSA. The new drug was cytotoxic to both lines at doses as low as 50 nM for 1 h. N-(5,5-Diacetoxypentyl)doxorubicin produced DNA interstrand cross-linking in both lines. The cross-linking appeared to increase in both lines following drug treatment, but the increase was greater in the resistant line. This appeared to be due to an underestimation of cross-linking, particularly in sensitive HL-60, secondary to time-dependent DNA fragmentation that followed drug removal. This time-dependent DNA fragmentation was probably endonucleolytic cleavage (a feature of apoptosis) as characteristic nucleosomal ladders were produced by N-(5,5-diacetoxypentyl)doxorubicin treatment in a cotemporal time-dependent fashion. This novel anthracycline is the first of a family of alkylating anthracyclines designed to be water soluble, easy to formulate, and capable of producing DNA interstrand cross-linking. Because this last characteristic has previously been associated with doxorubicin analogues of great potency and low toxicity, these newer, more readily formulated drugs may have great clinical utility.

[Small intestine occlusion caused by the silent opening of liver hydatid cysts into the peritoneum. Apropos of an uncommon case]

The authors report one exceptional case of organic small bowel occlusion. The etiological diagnosis was performed by ultrasonographic examination and showed two hydatid cysts of the liver opened into the peritoneum and a peritoneal fluid collection corresponding to the hydatid fluid. The authors emphasize the absence of clinical symptoms during the opening of the hydatid cysts of the liver into the peritoneum and the usefulness of emergency ultrasonographic examination of the entire abdomen in cases of small bowel obstruction without any evident etiology.

Hypoglycemia during prolonged exercise in normal men

Hypoglycemia (blood glucose less than 45 mg per deciliter [less than 2.5 mmol per liter]) occurred in seven of 19 healthy men who exercised to exhaustion on a cycle ergometer at 60 to 65 per cent of maximal aerobic power. The hypoglycemic subjects exercised for 15 to 70 minutes despite blood glucose levels of 25 to 48 mg per deciliter (1.4 to 2.7 mmol per liter), and their exhaustion time (mean +/- S.E.M., 142 +/- 15 minutes) was not significantly different from that of the euglycemic group (165 +/- 11). Plasma epinephrine was inversely related to blood glucose (P less than 0.01) and was three times higher in the hypoglycemic subjects (P less than 0.05). Glucose ingestion (40 or 80 g per hour) prevented the hypoglycemia and resulted in a smaller rise in plasma epinephrine but did not alter perceived exertion or consistently delay exhaustion. We conclude that hypoglycemia occurs in normal subjects during prolonged exercise and results in an exaggerated rise in plasma epinephrine. However, hypoglycemia fails to effect endurance, and its prevention does not consistently delay exhaustion.

[Linoleic acid synthesis in oleaginous seeds]

Fats are synthetized in oleaginous seeds according to the following diagram: lipid synthesis, very slow immediately after fecundation, becomes very intensive between the second and the fifth weeks after florescence and is reduced to zero at the end of maturation. The desaturating activity of ammonium oleate is important in the first stages of development of the seeds.