Hepatocellular carcinoma cell lines from diethylnitrosamine phenobarbital-treated rats. Characterization and sensitivity to endothall, a protein serine/threonine phosphatase-2A inhibitor

Primary hepatocellular carcinoma (HCC) is probably one of the most common fatal forms of liver cancer. We have established permanent cell lines from diethylnitrosamine/phenobarbital induced primary rat liver carcinomas to study new anticancer therapies. The rat hepatocellular carcinoma cell lines (HR-2, HR-3, and HR-4) have been maintained in culture for over 3 years. They form tumors when transplanted sc or im into young syngeneic rats. Immunocytology (alpha-fetoprotein, albumin), biochemical (gamma-glutamyl transferase), and histochemical (glycogen) marker studies and electron microscopy (biliary canaliculi) showed unique, stable differentiation patterns in these tumor lines. They overproduced the c-met protooncogene product and formed colonies spontaneously in semisolid culture with high cloning efficiency (HR-2: 50%-80%, HR-3: 35%-50% and HR-4: 50%-65%). The sensitivity of these cell lines to inhibitors of protein ser/thr phosphatase-2A (PP2A), a key enzyme in the control of G1/S and G2/M cell cycle phase transitions in eukaryotes, was studied in vitro. The specific, weak inhibitor of PP2A, endothall, caused dose- and time-dependent cytostasis specifically in G2/M. The cells died later by apoptosis, which was confirmed by cytology (annexin V-FITC labeling, propidium iodide painting of apoptotic bodies) and by fluorescent activated cell sorter (FACS) DNA measurements. The HR-2, HR-3, HR-4, and Zajdela hepatocellular carcinomas were most sensitive to endothall (IC50 of 1.7, 1.2, 0.9, and 1.7 microg/mL), whereas newborn rat hepatocytes growing exponentially in primary culture (IC50 = 6.2 microg/mL), rat DHD/K12 colon carcinoma cells (IC50 = 3.6 microg/mL), or human HT-29 colon carcinoma cells (IC50 = 4.9 microg/mL) were less sensitive. Thus, endothall inhibits preferentially HCC growth and these new rat hepatocellular carcinoma lines may be useful for further biochemical and pharmacological studies on PP2A inhibitors, and for testing new forms of treatment of hepatic cell carcinomas.     

Plasmodium falciparum parasites in French Guiana: limited genetic diversity and high selfing rate

The genetic characteristics of Plasmodium falciparum isolates collected in French Guiana, where malaria transmission is low and occurs in isolated foci, were studied. Blood samples were collected from 142 patients with symptomatic malaria and typed using a polymerase chain reaction-based strategy for merozoite surface protein-(MSP-1) block 2, the MSP-2 central domain, and glutamate-rich protein (GLURP) repeat domain polymorphism. This showed that the parasite population circulating in French Guiana presented a limited number of allelic forms (4, 2, and 3 for MSP-1 block 2, MSP-1, and GLURP, respectively) and a small number of mixed infections, contrasting with the large genetic diversity of parasite populations and infection complexity reported for Africa, Asia, and other parts of South America. Two groups of isolates displaying identical 3 loci allele combinations were further studied for the Pf332 antigen, histidine-rich protein-1, thrombospondin-related anonymous protein, and Pf60 multigene family polymorphism. Within each group, most isolates were identical for all markers tested. This suggests a high rate of self-fertilization of P. falciparum parasites in French Guiana, resulting in homogenization of the population. The implications of these findings for malaria control in areas of low endemicity are discussed.     

Syndrome of body fat redistribution in HIV-1-infected patients: relationships to cortisol and catecholamines

OBJECTIVE: Alterations of body fat distribution have been recently reported in HIV-infected patients. We aimed to investigate whether the hormones modulating adipose tissue metabolism could be implicated. SUBJECTS: We investigated twenty-eight HIV-infected patients who had developed abdominal fat, combined with peripheral lipodystrophy in 25 cases and 'buffalo hump' in 2 cases, but who had otherwise improved on antiretroviral therapies. Twelve patients with no change in body fat, matched for age, disease control and treatment, were studied as controls. MEASUREMENTS: Body composition was assessed by bioelectrical impedance analysis. Subcutaneous (SAT) and visceral (VAT) compartments of total abdominal adipose tissue (TAT) were measured by computed tomography. Resting metabolic rate (RMR) was assessed by indirect calorimetry. Endocrine investigations included plasma thyroid hormones, cortisol, testosterone, oestradiol and 24-hour urinary free cortisol (UFC) and catecholamines. RESULTS: Despite similar body mass index, the patients with body fat alterations showed significantly larger VAT and higher VAT:TAT ratio than controls (P = 0.002 and 0.0001, respectively). In these patients, RMR was significantly higher than estimated according to the Harris-Benedict formula (+ 19.7 +/- 11.6 %, P = 0.0001) and correlated with VAT (r = 0.58, P = 0.003) and 24-hour urinary output of catecholamines (r = 0.67, P = 0.002), that was significantly increased in comparison with controls (1737 +/- 1228 vs 476 +/- 292 nmol, P = 0.013). We also found a significant correlation between VAT and UFC (r = 0.41, P = 0.042) that was absent in controls, although levels of UFC were similar in the two groups. CONCLUSIONS: Our data suggest that body fat redistribution may involve cortisol and catecholamine actions. While high release of catecholamines may enhance RMR through increased lipolysis, cortisol may promote central fat storage. These effects might be related both to persistent hormonal responses to stress becoming inappropriate while disease control improved and to an increased sensitivity of visceral adipose tissue to cortisol in affected patients.     

Visceral leishmaniasis in HIV-infected patients in the south of France.

Between 1989 and 1993, investigations by classical parasitological procedures of 139 HIV-infected adults living in visceral leishmaniasis (VL) endemic areas showed that 10 of them (7.2%) were positive for Leishmania (by stained smears and culture). In the same period we identified 15 VL cases in patients not infected with HIV. Thus, 40% (10/25) of our VL cases were associated with HIV infection.     

Pancreatic pseudotumors: Computed tomography

Although pancreatic disease is suspected initially by historical or biochemical findings, the nature of the pathologic process in the past was frequently established only through invasive procedures. Inferences can be drawn from routine roentgenologic examinations, but visualization of the pancreas has only recently been achieved. Of the currently available noninvasive imaging procedures, computed tomography, in our opinion, is the screening procedure of choice. Care in the interpretation of pancreatic masses must be exercised since some of the findings can be attributed to anatomic variants, normal adjacent structures, or other neighboring pathologic processes.     

Relationship between the liver and lymphocytotoxic alloantibodies in inbred rats. Specific absorption by nonparenchymal liver cells

Liver allografts have a privileged status with regard to hyperacute rejection. In this experimental study, we have used extracorporeal liver hemoperfusion in sensitized rats in order to analyze reactions between lymphocytotoxic antibodies and the liver. In sensitized BN rats, a donor-specific (Lewis) extracorporeal liver hemoperfusion can delay hyperacute rejection of heart allografts and reduce the level of lymphocytotoxic antibodies. The decrease in the level of antibodies could be due to massive absorption of antibodies by the liver or to release of major histocompatibility complex antigens in a soluble form. Immunofluorescent examination of the hemoperfused liver revealed important deposits of C3 on Kupffer cells and of IgG on sinusoidal cells. On the contrary, in control rats in which a third-party (DA) liver hemoperfusion was performed, heart allograft survival was less prolonged, the decrease in the level of lymphocytotoxic antibodies was not significant, and the deposits of IgG and C3 were much less evident. The level of circulating immune complexes was unchanged after a donor-specific or a third-party liver hemoperfusion. These results support the hypothesis that resistance of the liver to hyperacute rejection might be due to a massive and nontoxic absorption of lymphocytotoxic antibodies on nonparenchymal liver cells.     

Ofloxacin (RU 43280). Clinical study

Thirty-two patients were treated by ofloxacin on bacteriological documented infections. They were Enterobacterias: n = 15 (MIC less than or equal to 0.06 to 0.5 microgram/ml); Pseudomonas aeruginosa and Acinetobacter: n = 1 (MIC 0.5 and 4 micrograms/ml); Staphylococcus: n = 6 (MIC less than or equal to 0.06 to 4 micrograms/ml); Pneumococcus: n = 1; Mycoplasma: n = 1; Chlamydia psittaci: n = 2; Legionella pneumophila: n = 1; Rickettsias: n = 4 (three mediterranean fevers one query fever). Ofloxacin was given orally from 400 to 800 mg per day (5 to 15 mg/kg/day). It was used alone 26 times and on 6 occasions it was associated with rifampin on 6 staphylococcal infections. On 19 cases it was used after failure or intolerance of initial therapy. Thirty times it was the first antibiotic substance used. Results were good mainly: 1) on nine pneumonitis (enterobacterias: 4; Pneumococcus: 1; Mycoplasma: 1; Chlamydia: 2; Legionella: 1) during a mean duration of twenty days; 2) urinary infections (n:7) provoked by E. coli and Enterobacter cloacae (mean duration: 20 days); 3) 4 osteo-articular-infections (mean duration: 77 days); 4) Rickettsial infections (n:4) during a mean duration of 11 days. Results are particularly noteworthy because patients treated had severe infections: 12 bacteremias, 1 endocarditis and 1 purulent meningitis. None severe adverse effect was observed.