Induction of unscheduled DNA synthesis by the carcinogen 7-bromomethylbenz(a)anthracene and its removal from the DNA of normal and xeroderma pigmentosum lymphocytes

The carcinogen 7-bromomethylbenz(a)anthracene (BBA), which can bind strongly to DNA, induces unscheduled DNA synthesis (DNA repair) in normal lymphocytes but almost none in lymphocytes from patients with Xeroderma pigmentosum (XP), and inherited disease known to be defective in excision repair of ultraviolet-damaged DNA. We studied [³H]BBA's ability to bind to DNA of normal and XP lymphocytes, its influence on unscheduled DNA synthesis, and its removal from the DNA of both cell types. We found that 20–30% of the BBA is bound to macromolecules other than DNA and that its binding to DNA is essentially complete after 30 min. The induction of unscheduled DNA synthesis by the carcinogen in XP lymphocytes was approximately 10% of that induced in normal lymphocytes. While 15–20% of the BBA was removed from the DNA of normal cells 6 h after treatment, only 1–2% was removed from the DNA of XP cells. Thus, XP cells not only are defective in repairing ultraviolet-damaged DNA and excising thymine dimers but also fail to repair DNA damaged by certain carcinogens, and, most importantly, fail to remove the DNA-bound carcinogen, BBA.     

Constituents of the essential oil of Lavandula latifolia

Thirty components were identified in Lavandula latifolia essential oil (spike oil). One of the compounds, espliegol (δ-terpineol), is a new natural product.     

Receptor-mediated regulation of calcium mobilization and cyclic GMP synthesis in neuroblastoma cells

In neuroblastoma N1E 115 cells, carbachol, histamine and PGE1 elevated cyclic GMP content and, induced the efflux of preloaded 45Ca2+, the release of membrane-bound Ca2+ measured by fluorescent CTC, and the increase in [Ca2+]i as measured by Quin 2 fluorescence. The time course of the responses, the absolute requirement of extracellular Ca2+, the inhibition by receptor blockers, and the concentration dependency on histamine were all similar between these responses. The observation indicates that the mobilization of Ca2+, especially the increase of [Ca2+]i, may be intimately linked to the synthesis of cyclic GMP in the cells.     

Forward mutation assay of V79 cells to 6-thioguanine resistance in a soft agar technique that eliminates effects of metabolic co-operation

A technique involving culture in soft agar was used for the assay of forward mutation of V79 cells to 6-thioguanine (6TG) resistance. The main reason for the use of soft agar was to prevent reduction in recovery of mutants depending on the cell density plated for mutation selection, which is the chief problem in the liquid method, and which results mainly from metabolic co-operation due to cell-to-cell contact.V79 cells grew well in fortified soft agar medium (DMEM + 20% FBS) showing cloning efficiencies (>80%) as high as in liquid culture. Therefore, V79/HGPRT mutagenesis could be assayed quantitatively in soft agar culture.The frequency of 6TG-resistant colonies in agar selective medium increased linearly with increase in concentration of EMS. Toxicity and mutagenic responses were greater in soft agar than in liquid culture.In cultures of untreated and EMS-treated cells, more than 95% of the 6TG-resistant colonies isolated were aminopterin-sensitive.Use of soft agar for selection prevented the reduction in the number of mutants with increase in the size of incula on plating up to 1?2 × 10⁶ cells per 9-cm dish: in liquid culture, even with a lower plating number (2 × 10⁵ cells per 9-cm dish), a notable reduction in numbers of mutants was observed. This character was re-examined in a reconstruction experiment. The results show that, when up to 2 × 10⁶ cells were plated per 9-cm dish, 6TG-resistant cells were almost completely recovered from the soft agar medium, whereas only 10% were recovered from liquid culture.     

Furanosesquiterpenes from the essential oil of myrrh

An examination of the essential oil of myrrh from Commiphora molmol has permitted the identification of 1(10)Z,4Z-furanodiene-6-one, 2-meth     

Platelet calcium pump activity in essential hypertensives and their first-degree relatives

Intracellular free Ca²⁺ concentration has been shown to be elevated in platelets of patients with essential hypertension. This study was designed to characterize Ca²⁺-pump activity of the platelet membranes (surface and intracellular) in these patients. A double-blind study was carried out. Untreated and treated (on R-blockers) essential hypertensives were studied in comparison with normotensive control subjects. First degree blood relatives of essential hypertensives were also studied. The Ca²⁺-activation kinetics of the enzyme showed a significant decrease in the V_max. (for the plasma- and intracellular membranes) and Km (for the intracellular membranes) in the essential hypertensive patients. Increased platelet membrane cholesterol content was observed in these patients. Lowered Ca²⁺-efflux by Ca²⁺-ATPase may lead to elevated intracellular free Ca²⁺-levels in platelets of essential hypertensives. A lowered Ca²⁺-ATPase activity may emerge as a marker for essential hypertension.     

Chemotype pattern differentiation of Thymus pulegioides on different substrates

Relationships between soil chemistry and population chemotype structure of Thymus pulegioides have been studied. The analysis of correlations suggest that an increased carbonate content in soil decreases the chemotype diversity of a population (as calculated by use of the Shannon index): the proportion of linalool chemotype plants rises and that of the phenol chemotype plants declines. In addition, the chemotype diversity decreases with increasing frequency of linalool chemotype, and increases with increase of carvacrol chemotype.     

Essential trace elements in humans

Serum arsenic concentrations of persons suffering from renal failure and undergoing hemodialysis treatment (n=85) and of healthy controls (n=25) were determined by hydride-generation AAS technique after microwave digestion. The results were evaluated by comparing the values of both groups, considering physiological factors and individual data, as well as comorbid conditions of the hemodialysis (HD) patients. Serum arsenic levels were diminished in the patient group compared with controls (mean values 8.5±1.8 ng/mL vs 10.6±1.3 ng/mL). Furthermore, additional diseases within the hemodialysis group, particularly injuries of the central nervous system (CNS), vascular diseases, and cancer, were correlated to occasionally markedly decreased serum arsenic concentrations. It was concluded that arsenic homeostasis is disturbed by HD treatment and certain additional diseases. Desirable arsenic concentrations in the body seem to be reasonable. This consideration results in the conclusion that arsenic could play an essential role in human health. Thus, reference arsenic concentrations in different human tissues and body fluids should be established in order to recognize not only arsenic intoxication, but also arsenic deficiency. Perhaps arsenic deficiency contributes to the increased death risk of HD patients, and therefore, arsenic supplementations for patients with extremely low serum arsenic concentrations should be taken into account.     

4-Hydroxy-2-Nonenal Levels Increase in the Plasma of Patients with Adult Respiratory Distress Syndrome as Linoleic Acid Appears to Fall

Gas chromatography-mass spectrometry has been applied to the analysis of plasma linoleic acid and one of its oxidation products, 4-hydroxy-2-nonenal (HNE), in adult patients with the acute respiratory distress syndrome (ARDS). Peak areas of total ion chromatograms showed there to be negative correlations between loss of linoleic acid and formation of HNE (measured by selective ion monitoring) in 7 out 10 patients studied. When HNE was quantitated by selective ion monitoring, with reference to a pure standard of HNE and an internal standard of nonanoic acid, ARDS patients showed significantly increased levels of HNE (0.412 ± 0.023 nmol/ml) compared with normal healthy controls (0.205 ± 0.018 nmol/ml).     

Environmental factors affecting the lipid metabolism in Rosmarinus officinalis L

The effect of some environmental factors on the lipid metabolism was studied in two chemotypes of Rosmarinus officinalis L. Epicuticular hydrocarbons (EH), epicuticular fatty acids (EFA), whole leaf fatty acids (WLFA) and essential oils (EO) were extracted and analysed by GC-MS during winter 1991–1992 and related to temperature and moisture variations. Leaf fresh and dry wts were determined along with some morphophysiological parameters such as specific leaf weight (SLW) and specific leaf area (SLA). Leaf areas were calculated by image analysis and statistically processed as for chemical data. The results indicated that in R. officinalis the response to some environmental factors, with particular reference to temperature and moisture, was an increase in epicuticular hydrocarbons and a decrease in epicuticular fatty acids, leaf fatty acids and essential oils. Qualitative changes in the chemical composition of the above lipid classes were found to be correlated with temperature changes. From a chemosystematic viewpoint, a clear separation between the two chemotypes was achieved only when epicuticular hydrocarbons and essential oils were considered as chemosystematic characters.