Uptake and DNA photodamage induced in plant cells in vivo by two cationic porphyrins

The in vivo uptake of two cationic porphyrins: mesotetra (4-N-methylpyridyl)porphine (T₄MPyP) and its zinc complex (ZnT₄MPyP) was determinedin Allium cepa meristematic cells. Both photosensitizers (10^–7M for 4 h) penetrated into the nucleus producing a red fluorescenceof chromatin under blue-violet (436 nm) exciting light. Theability of T₄MPyP and ZnT₄MPyP to induce DNA photodamage wasmeasured by the sister chromatid exchange (SCE) test. 5-Bromo-2'-deoxyuridine-substitutedchromosomes treated with both the porphyrins (10^–8 M for4 h) showed increased frequencies of SCE when they were postirradiatedwith 436 nm light. A higher genotoxic effect was observed forZnT₄MPyP than the other compound. ¹To whom correspondence should be addressed     

Anti-Hepatitis A Virus Immunoglobulin M Antibodies in Urine Samples for Rapid Diagnosis of Outbreaks

The main goal of this study was to test the feasibility of using urine for diagnosing hepatitis A virus (HAV) infections. A correlation of 90.78% between the test results of urine and serum samples was obtained. Four outbreaks of hepatitis A were confirmed by testing only urine samples. The levels of anti-HAV immunoglobulin M (IgM) antibodies in urine samples remained stable during 6 months of storage at −70°C but decreased when the samples were stored at 4°C. The results of tests of samples obtained 2 and 6 months after infection suggested that IgM levels decline more rapidly in urine than in serum.     

Primary neuroendocrine small cell undifferentiated carcinoma of the parotid gland

Neuroendocrine small cell carcinoma is a malignant neoplasm that most frequently arises in the lung. Salivary gland involvement is rare, and the parotid is the main gland affected. We describe the fine-needle aspiration (FNA) cytology findings, the immunophenotypical study and the differential diagnosis of a small cell carcinoma that presented in the parotid of a 91-year-old man. The tumour was treated only with radiotherapy and presented a complete response, with no evidence of the disease after three years of follow-up. This is the first case reported in the literature with good outcome after exclusive irradiation.     

Evidence for two types of nicotinic receptors in the cat carotid body chemoreceptor cells

Current concepts on the location and functional significance of nicotinic receptors in the carotid body rest on α-bungarotoxin binding and autoradiographic studies. Using an in vitro preparation of the cat carotid body whose catecholamine deposits have been labeled by prior incubation with the tritiated natural precursor [³H]tyrosine, we have found that nicotine induces release of [³H]catecholamines in a dose-dependent manner (IC₅₀=9.81 μM). We also found that mecamylamine (50 μM) completely abolished the nicotine-induced release, while α-bungarotoxin (100 nM; ≈20 times its binding K_d) only reduced the release by 56%. These findings indicate that chemoreceptor cells, and perhaps other carotid body structures, contain nicotinic receptors that are not sensitive to α-bungarotoxin and force a revision of the current concepts on cholinergic mechanisms in the carotid body chemoreception.     

Biliary lipid secretion during the prereplicative phase of rat liver regeneration.

The prereplicative phase-related changes in spontaneous and taurocholate-induced biliary lipid secretion were studied in anaesthetized male Wistar rats (250 g). Rats underwent two-thirds hepatectomy 1, 6 or 12 h before starting to collect bile samples. As compared with non-hepatectomized rats, biliary lipid secretion was increased at 1 h after hepatectomy and then restored to values similar to the control group up to 12 h after hepatectomy. In separate experiments, taurocholate was infused (200 nmol/min/g calculated liver weight) through the jugular vein over 80 min. Both taurocholate-induced bile flow and bile acid output were similar in control and hepatectomized rats, regardless of the time of the prereplicative phase considered. By contrast, taurocholate-induced lecithin and cholesterol outputs were markedly modified. The former was lowered throughout the prereplicative phase, whereas the latter increased at 6 h and decreased at 12 h. In summary, these results indicate that shortly after hepatectomy bile acid-induced biliary lipid secretion is profoundly modified, probably due to changes in the plasma membrane involved in preparing the hepatocyte to enter the cell cycle.     

Difference in label length between demethylchlortetracycline and oxytetracycline: Implications for the interpretation of bone histomorphometric data

Summary We measured the individual lengths of fluorescent labels on the three subdivisions of the endosteal envelope in iliac bone biopsy specimens produced by the administration of both oxytetracycline and demethylchlortetracycline. Fifty-one healthy subjects and 53 patients with postmenopausal osteoporosis were labeled in the stated order, and 8 osteopenic patients were labeled in the reverse order. Whatever the order of administration, the demethylchlortetracycline label was longer than the oxytetracycline label. We conclude: (1) the difference in label lengths reflects a difference between the two compounds in some intrinsic property, whether physical, chemical, or pharmacokinetic. (2) If the calculation of extent of mineralizing surface is based on the mean length of the two labels, a suitable correction should be applied to the shorter label; alternatively, the length of the longer label alone should be used. (3) Unlabeled osteoid not due to label escape probably results from slow terminal mineralization after cessation of matrix synthesis during which too few tetracycline molecules are incorporated to exceed the threshold for visible fluorescence, rather than from the temporary interruption of mineralization followed by its resumption.     

Intermittent stridor and dyspnea in an adult.

We describe an adult patient who had stridor and dyspnea as initial symptoms of a thyroglossal duct cyst. Spirometry and noninvasive imaging techniques have been useful for diagnosis of this condition.     

Biological monitoring of occupational exposure to n-hexane by exhaled air analysis and urinalysis

Summary To compare two methods of biological monitoring for the evaluation of risk of occupational exposure to n-hexane, we analyzed the relationship between environmental exposure to this solvent and urinary excretion of 2,5-hexanedione and n-hexane in exhaled air in 69 workers employed in the shoe industry. Environmental exposure to the solvent was monitored with personal diffusive samplers, which were desorbed with carbon sulfide and analyzed by gas chromatography. To measure 2,5-hexanedione, urine was subjected to acid hydrolysis, separation in octadecyl silane columns, elution with 5% aqueous acetonitrile solution and extraction with dichloromethane, followed by gas chromatography. In exhaled air, n-hexane was measured with a sampling system that permitted concentration of aliquots of end-exhaled air (alveolar air) from one or more exhalations in a tube packed with activated charcoal, which was then desorbed with carbon sulfide and analyzed by gas chromatography. Concentrations of n-hexane in breathing zone air were significantly correlated with urinary concentrations of 2,5-hexanedione (r = 0.88) and with exhaled air n-hexane (r = 0.86); in addition, the two biological indicators correlated significantly (r = 0.70). Analyses in both exhaled air and urine were thus considered useful for biological monitoring of the risk of exposure to n-hexane.     

Splinting of traumatized anterior teeth using the nylon-resin technic

In this paper the nylon-resin technique is proposed as the idoneous fixing technique of dentary displacement treatment and/or radicle fracture due to dentoalveolar traumatisms, of high incidence in children. In order to probe the effectiveness and advantages of this technique a comparative study against the wire-resin technique was done. The fixing time proposed for both procedures was 14 days. The techniques were applied in the same number of patients indistinctly in age, sex, affected teeth, and type of lesion. After evaluation we observed that the proposed technique is superior in several aspects: fulfils with the requirements of an ideal ferule, is aesthetic, easier to elaborate, more resistant, more compatible with tissues, and because of their semirigidity, more functional.