Metabolism of benzo(a)pyrene by human lung microsomal fractions

The metabolism of benzo(a)pyrene was studied using microsomal fractions obtained from human lung derived at either resection or autopsy. The rates of metabolism and metabolite distribution were monitored using high pressure liquid chromatography and the metabolic rates were noted to be similar to those obtained using rat lung microsomes. In contrast to the rat, human lung microsomes appear to form a higher percentage of the 7,8-dihydro-7, 8-diol or 9,10-dihydro-9, 10-diol of benzo(a)pyrene as a fraction of the total metabolites. However, there was a significant variation among the human lung microsomal preparations which might reflect the clinical diagnosis and/or individual variation.     

Induction of mutations inSerratia marcescens by a proteosynthesis block

The formation of colour mutations ofSerratia marcescens by the action of chloramphenicol was studied. Pink variants were the commonest; the proportion of white variants was much smaller. Almost 100% mutations were formed in a two-day culture containing 100 μg. chloramphenicol/ml. Comparative experiments showed that the change in pigment formation was hereditary, i.e. that actual mutation, and not selection of chloramphenicol-resistant mutants, occurred. Mutation occurred both in strain 151 and strain HY. The resultant mutations remained constant throughout ten passages on normal nutrient medium. The minimum chloramphenicol concentration which produced an increase in the mutation frequency was 5 μg./ml. The combined effect of X-ray irradiation and chloramphenicol treatment somewhat stimulated the increase in the frequency of mutation as compared with cells which were only irradiated. The increase in the frequency of mutation was much slower on solid medium containing chloramphenicol.     

The genus Candida Berkhout

The properties of 53 fermentation type II strains of the genusCandida Berkhout were studied. The strains in question were originally identified asCandida tropicalis (Castellani) Berkhout,Candida pelliculosa Redaelli,Candida robusta Diddens et Lodder,Candida intermedia (Cif. et Ashf.) Langeron et Guerra,Candida langeroni Dietrichson,Candida obtusa (Dietrichson) v. Uden et Carmo Sousa and as various intermediate forms between these and other similar species. The classification criteria were extended by a number of very important characteristics, such as the degree of utilization of raffinose, the assimilation of lysine, xylose, cellobiose, maltotriose, maltotetraose and arabinose, virulence for mice, nutrient requirements, serological properties, etc. Actual classification was based on the numerical method of a similarity count. On the basis of this extension of the classification criteria, the characteristics of the speciesCandida tropicalis (Castellani) Berkhout andCandida pelliculosa Redaelli were defined in greater detail.Candida intermedia, evaluated on the basis of previously employed characteristics (lactose utilization, non-assimilation of KNO₃) does not appear to be a separate species, but a collection of different border-line forms of other species of this group.Candida robusta Diddens et Lodder is regarded as a member of the genusSaccharomyces, notCandida. The varietiesCandida tropicalis var.lambica andCandida pelliculosa var.cylindrica likewise do not seem to belong to the species concerned and will have to be studied in greater detail from the genetic aspect, in relation to other membrane-forming types ofCandida. The authors' extension of the classification criteria considerably reduced intraspecific variability, particularly in the speciesCandida tropicalis (Castellani) Berkhout, and led to greater accuracy in the practical diagnosis of this species, which is frequent in clinical material.     

Cutaneous metastasis of occult hepatocellular carcinoma: a case report

BACKGROUND: Skin metastases from hepatocellular carcinoma (HCC) represented only 0.8% of all known cutaneous metastases in a recent large series. The most frequent site appears to be the head, but this fact has received little attention. An accurate cytologic diagnosis is extremely difficult in patients with unknown liver dysfunction. We report the cytologic features of a face metastasis from occult HCC. CASE: A 65-year-old woman presented with a mass in the right preauricular region of 2 months' duration. Her past medical history was noncontributory. Fine needle aspiration cytology was performed. Following the cytologic diagnosis, computed tomography revealed a 6-cm mass in the right lobe of the liver, portal vein thrombosis and involvement of the superior vena cava. The smears were very cellular. The most frequent pattern was trabecular with transmural endothelization. The cells had an epithelial appearance and polyhedral shape, exhibiting distinct borders. The nuclei were centrally placed, with a prominent nucleolus. The cytoplasm was granular. There were numerous atypical bare nuclei. Subsequent staining with antihepatocyte showed positivity in most tumor cells. The final diagnosis was metastatic HCC. CONCLUSION: HCCs should be considered in the differential diagnosis of carcinomas metastatic to the face, even in the absence of liver symptoms.     

Effects of castration and hormone replacement on male sexual behavior and pattern of expression in the brain of sex-steroid receptors in BALB/c AnN mice

Little is known about the hormonal regulation of sexual behavior and about the pattern of expression in the brain of sex-steroid receptors in the BALB/c AnN strain of mice (Mus musculus). In this study, 8-week old male BALB/c AnN mice were castrated and the temporal course of decline of sexual behavior was studied, as well as the effects of daily treatment with either testosterone propionate (TP), estradiol benzoate (EB), or dihydrotestosterone propionate (PDHT). Castration resulted in rapid decline of sexual behavior, in both control or vehicle-treated mice. TP maintained full sexual behavior of castrated mice, while PDHT or EB did not have this effect. The expression of ER-alpha dropped nearly 50% after castration, and this pattern remained in TP or PDHT-treated mice, while EB increased the ER-alpha mRNA levels to almost the same values as in intact control mice. The same pattern was found when ER-beta mRNA levels were analyzed. The expression of the PR-A/B gene in the different brain regions in intact mice and after castration, or among the differently treated mice, showed significant differences between normal and castrated mice at all times in all brain regions studied, with the exception of the frontal cortex. Castration reduced the expression of AR by 10-fold, as compared to intact control mice, while TP or PDHT treatment returned its expression to the same levels as in intact control mice, in all brain areas studied. The changes are more prominent in POA-HIP than in HYP and CF. These results demonstrated a rapid decline of sexual behavior in this strain of mice after castration, and show that only TP was able to maintain male sexual behavior, with no correlation with the pattern of expression of sex hormone receptors in specific areas of the mouse brain.     

Immunogenicity and safety assessment of the Cuban recombinant hepatitis B vaccine in healthy adults.

Manufactures of biotechnological/biological products (including vaccines) frequently make changes to manufacturing processes of products both during development and after approval. In our case, a non-inferiority bridging study was carried out to demonstrate that changes in the production plant facilities of Cuban recombinant hepatitis B vaccine, Heberbiovac HB, did not affect the safety and immunogenicity of the vaccine. This controlled, randomized, doubled-blinded trial included 501 volunteers, aged between 20 and 64, who were given three doses of vaccine (20 microg HBsAg/mL) at month 0, 1, and 2. Four lots were evaluated (three corresponding to the new production facilities and a control one produced in the older facilities). One month after the third dose, were observed protective levels of anti-HBsAg in 97% of the subjects that concluded the study with a geometric mean antibody titer (GMT) of 931.18 IU/L. Normal values of body mass index (BMI), the younger ages, and being a female, were significantly related to a good antibody response. The vaccine was well tolerated. Pain at the injection site was the most commonly reported symptom. We conclude that Heberbiovac HB vaccine maintains its characteristics after the modifications carried out in the production plant facilities and both, lot obtained in previous facilities and in the new ones, are comparable in terms of safety and immunogenicity.     

Mitochondrial targeting of farnesyl diphosphate synthase is a widespread phenomenon in eukaryotes

Cellular internalization of cell-penetrating peptide HIV-1 Tat basic domain (RKKRRQRRR) was studied in Triticale cv AC Alta mesophyll protoplasts. Fluorescently labeled monomer (Tat) and dimer (Tat(2)) of Tat basic domain efficiently translocated through the plasma membrane of mesophyll protoplast and showed distinct nuclear accumulation within 10 min of incubation. Substitution of first arginine residue with alanine in Tat basic domain (M-Tat) severely reduced cellular uptake of the peptide (3.8 times less than Tat). Tat(2) showed greater cellular internalization than Tat (1.6 times higher). However, characteristics of cellular uptake remained same for Tat and Tat(2). Cellular internalization of Tat and Tat(2) was concentration dependent and non-saturable whereas no significant change in cellular uptake was observed even at higher concentrations of M-Tat. Low temperature (4 degrees C) remarkably increased cellular internalization of Tat as well as Tat(2) but M-Tat showed no enhanced uptake. Viability test showed that peptide treatment had no cytotoxic effect on protoplasts further indicating involvement of a common mechanism of peptide uptake at all the temperatures. Endocytic inhibitors nocodazole (10 muM), chloroquine (100 muM) and sodium azide (5 mM) did not show any significant inhibitory effect on cellular internalization of either Tat or Tat(2). These results along with stimulated cellular uptake at low temperature indicate that Tat peptide is internalized in the plant protoplasts in a non-endocytic and energy-independent manner. Competition experiments showed that non-labeled peptide did not inhibit or alter nuclear accumulation of fluorescent Tat or Tat(2) suggesting active transport to the nucleus was not involved. Studies in mesophyll protoplasts show that internalization pattern of Tat peptide is apparently similar to that observed in mammalian cell lines.