Induction of somatic embryogenesis in leaf-derived callus of Vicia narbonensis L.

A method for the induction of somatic embryogenesis in callus cultures, using explants from mature leaves of Vicia narbonensis L., is described. Callus developed on a solid medium (Murashige and Skoog 1962), which was supplemented with low concentrations of picloram and benzylaminopurine.

Detection of 3-hydroxy-3-methyloxindole in human urine.

During routine toxicological screening of urine for possible drug overdose, using two-dimensional thin-layer chromatography, an unknown substance was periodically detected that could not be related to any known drug. The substance was mass-isolated from the urine of a schizophrenic patient, who excreted it prolifically and it was chemically identified as 3-hydroxy-3-methyloxindole by mass spectrometry and 1H- and 13C-NMR. The structure was confirmed by synthesis through methylation of isatin.

Cross-contamination of human esophageal squamous carcinoma cell lines detected by DNA fingerprint analysis.

DNA "fingerprint" analysis has recently become known as a valuable technique for positive identification of any given individual. The chances for mistaken identity have been estimated to be 10(-6) for close siblings or as little as 10(-23) for randomly selected individuals. This methodology thus represents a significant improvement over previously established identification tests using protein or enzyme analysis techniques and has already found application in forensic medicine.

Nicotine gum and psychological support in smoking cessation. A pilot study in South Africa.

The effectiveness of freely chosen, personally paid-for, 2 mg nicotine gum (Nicorette; MPS Laboratories) as an adjunct to group psychological support in 12 heavy smokers motivated to stop was compared with 11 matched controls who chose not to use gum and received psychological support only. After 6 months, 50% of the group using gum had stopped smoking compared with 27% of the controls (verified by the measurement of carboxyhaemoglobin concentrations). There was a tendency to underuse gum despite careful instructions in its use, but surprisingly there was a significant negative correlation between the amount of gum used and stopping smoking.

Smoking, oncogenes and human lung cancer. A review of recent laboratory evidence linking smoking and lung cancer.

Recent molecular genetic experiments conducted in the USA and The Netherlands have isolated specific mutations in human lung cancer cells. These data implicate the activation of the K-ras oncogene in the pathogenesis of adenocarcinoma of the lungs of heavy smokers and the deletion of DNA from the short arm of chromosome 3 in small-cell and non-small-cell carcinoma of the lung. The implications of these results are discussed and explained in the light of current DNA-manipulative technology which is now available in RSA.

Interferon-induced cytolysis correlates with the degree of transformation of epidermal cells.

The cytolytic activity of interferon (IFN) was evaluated for its ability to distinguish between paired sets of nontumorigenic/tumorigenic epidermal cells (JB-1/JB-8; D1/D11a) as well as a set consisting of nonpromotable, promotable, and tumorigenic epidermal cell lines (JB-6 clones 30, 21, and RT101). The viability of the cell types was measured in a microassay using histoplates. IFN-gamma and IFN-alpha/beta, when employed singly, demonstrated an equivalent and limited effect on the viability of all cell lines.

Sodium valproate poisoning. A case report.

A case of a severe overdose of sodium valproate (more than 10 times the therapeutic requirement) is discussed. The patient presented with central nervous, respiratory and cardiovascular depression and was treated with supportive therapy and haemoperfusion. However, on available data it would appear that haemoperfusion did not make a significant contribution towards the patient's recovery.

The specific binding of the thyroid hormones to matrix isolated from rat liver nuclei.

Specific binding sites for the thyroid hormones have been demonstrated in the liver nuclear matrix, a structural framework of the nucleus. When labelled 3,5,3'-tri-iodo-L-thyronine ([125I]T3) is injected into rats, 5% of the total nucleus bound T3 is bound to the matrix after 1 hour. However, when either isolated nuclei or isolated nuclear matrices were incubated with [125I]T3 in vitro, a 3- to 7-fold greater number of specific T3 binding sites were revealed in the nuclear matrix.

The induction and transplantation of hepatomas in Wistar and BD IX rats.

Hepatomas were induced by feeding rats laboratory chow containing 0,6375 g of 3'-methyl-4-dimethylaminoazobenzene per kg for 3 to 5 months. DAB-1 was a hepatoma induced in randomly bred Wistar rats and was transplanted for 3 years after which it failed to grow in vivo but not in vitro. DAB-2 and DAB-3 are new transplantable hepatoma lines established in highly inbred DBIX rats.

The protective effect of phentolamine against cardiac arrhythmias in the rat.

Norepinephrine was given by continuous infusion at a rate of 80 microgram/kg/min for 2 min. Norepinephrine caused the appearance of cardiac arrhythmias, primarily ventricular extrasystoles. The prior administration of phentolamine, even in a dose which did not antagonize the pressor effect of norephinephrine, prevented extrasystole production by norepinephrine.

Afrikander cattle congenital goiter: characteristics of its morphology and iodoprotein pattern.

The morphology and some properties of the complex iodoprotein pattern of the genetically determined congenital goiter in Afrikander cattle is described. The goiter contained irregularly shaped follicles which were devoid of colloid and the follicular epithelial cells were elongated, measuring about 20 micrometer in length compared to 10 micrometer for normal thyroid cells. The goiter cells contained apical clusters of larger and more numerous lysosomes than normal thyroid cells.