Cytological analysis of tetraploid hybrids between sweet potato and diploid Ipomoea trifida (H. B. K.) Don.

Summary Tetraploid F₁ hybrids between Ipomoea batatas, sweet potato (2n = 6x = ca. 90), and diploid (2n = 2x = 30) I. trifida (H. B. K.) Don. showed various degrees of fertility reduction. The present study aimed to clarify its causes by cytological analysis of meiotic chromosome behavior in the diploid and sweet potato parents and their tetraploid hybrids. The diploid parents showed exclusively 15 bivalents, and the sweet potato parents exhibited almost perfect chromosome pairing along with predominant multivalent formation. Their hybrids (2n = 4x= 57–63) formed 2.6–5.0 quadrivalents per cell, supporting the autotetraploid nature. The meiotic aberratios of the hybrids were characterized by the formation of univalents, micronuclei, and abnormal sporads (monad, dyad, triad, and polyad). The causes underlying these aberrations were attributed in part to the multivalent formation, and in part to a disturbance in the spindle function. Three hybrids showing serious meiotic aberrations were very low in fertility. The utilization of the sweet potato-diploid I. trifida hybrids for sweet potato improvement is described and, further, the role of interploidy hybridization in the study of the sweet potato evolution is discussed.     

DNA synthesis and content in the macrophage nuclei of normal mice, during carcinogenesis and during the administration of retinoids to the animals

It has been found that nearly 50% of the lymph node and spleen macrophages (MP) of the CBA line mice contain DNA at levels superior to the diploid value (H2c--H4c in mononuclear MP, and up to H16c among polynuclear ones, the latter comprising 2.5-9.0% of the whole MP population). No DNA synthesis and mitosis were detected by autoradiography, cytophotometry, and cytomorphological analysis. During carcinogenesis the proportion of MP with elevated DNA amounts ("activated MPs") decreases due to their migration to tumours. Also immature MPs (1.6%) appear in the population, which synthesize DNA, but do not divide. Injection of retinoids restores the percentage of MPs with elevated DNA amounts to the levels characteristic of the intact animals, the fraction of DNA-synthetizing cells increasing up to 2.8%. It is proposed that retinoids may accelerate the processes of MP maturation, activation and renewing. A mechanism of cooperative action of MPs and retinoids is discussed in addition to the role of DNA hyper-replication.     

Serum ferritin, iron and transferrin in women with thyrotoxic Graves' disease before and after methimazole treatment

We investigated iron metabolism in 47 women with thyrotoxic Graves' disease. Serum iron, ferritin, transferrin, triiodothyronine and thyroxine concentrations were RIA measured before and after methimazole treatment when patients became euthyroid. The control group consisted of 52 healthy women. We noted that serum ferritin levels and the ferritin to transferrin ration were significantly lower while the iron to ferritin ratio was higher in patients before and after methimazole therapy. Iron concentration as well as the iron to transferrin and the iron to thyroid hormone ratios were decreased only before treatment.     

Synthesis of oligoribonucleotides by the N-phosphonate method using alkali-labile 2'-o-protective groups. II. Various aspects of using 2'-o-benzoyl and anisole protective groups

The N-acyl, 5'-O-trityl (MeOTr, (MeO)2Tr, Me3Tr), 2'-O-benzoyl (and anisole) nucleosides were prepared by selective aroylation of N,5'-protected nucleosides. By means of the reverse-phase microcolumn liquid chromatography it was shown that the rate of the aryl 2'----3'-isomerisation is lower in case of 2'-anisoylnucleosides and depends on structure of the 5'-O-protecting group. The prepared synthons were used for the manual H-phosphonate solid-phase synthesis of oligoribonucleotides (6-10-mers).     

Dot-enzyme-linked immunosorbent assay (dot-ELISA) for the rapid diagnosis of human fascioliasis

A dot-enzyme-linked immunosorbent assay (dot-ELISA) was developed as a fast and field applicable antibody detection tool for the diagnosis of human fascioliasis. The assay is performed using partially purified antigens from a species of Fasciola at 180 ng protein/dot (2 microliters) and serum samples at 1:20 dilution (1 microliter). Dot-ELISA results completely agreed with those of micro-ELISA. Antigen-coated nitrocellulose sheets stored for 3 mo at -20 C showed results identical to fresh sheets. Sera from patients with fascioliasis (n = 30) and other parasitic or viral infections (n = 120) were compared with sera from healthy controls (n = 14). Ninety samples can be tested within 90 min. The sensitivity, specificity, and speed of the assay may justify its use in laboratory and field studies.     

Characterisation and covalent labeling of the human placental methyltrienolone binding protein

Human placental cytosol contains an androgen binding protein which binds the synthetic androgen methyltrienolone (R 1881) with high affinity (Kd 8.7 nM) and with an average binding capacity of 518 fmol/mg cytosol protein. This study provides further evidence that this protein is distinguishable from classical androgen receptors on the basis of steroid specificity and sulphydryl group sensitivity. Covalent labeling studies have shown this protein, which we have called "the methyltrienolone binding protein", to have a mol. wt of 67,000 daltons.     

Nicotine and cannabinoids as adjuncts to neuroleptics in the treatment of Tourette syndrome and other motor disorders

Animal studies suggest nicotine and cannabinoids may significantly enhance the therapeutic value of neuroleptics in motor disorders. This was recently demonstrated in humans by the finding that chewing nicotine gum produced striking relief from tics and other symptoms of Tourette syndrome not controlled by neuroleptic treatment alone. It appears that the use of nicotine or cannabinoids may greatly improve the clinical response to neuroleptics in motor disorders.     

Cholinotoxicity induced by ethylcholine aziridinium ion after intracarotid and intracerebroventricular administration

The effect of ethylcholine aziridinium ion (AF64A) after an intracerebroventricular (icv) injection was compared to that obtained after an intravascular administration. Reductions in choline acetyltransferase (ChAT) and acetylcholinesterase activities in the hippocampus but not in the cerebral cortex or the corpus striatum were observed 10 days after bilateral injection of AF64A into the rat cerebroventricles (3 nmol/side). However, when AF64A was injected into the carotid artery (1 mumol/kg) following a unilateral opening of the blood-brain barrier by a hypertonic treatment, a significant decrease in ChAT activity was observed in the ipsilateral side of the cerebral cortex but not in hippocampus, corpus striatum, or cerebellum. High-affinity choline transport was reduced significantly 11 days after an icv injection of AF64A in all the above mentioned brain regions, and recovered 60 days post injection in the cerebral cortex and in the corpus striatum but not in the hippocampus. Our results suggest that in various brain regions, AF64A causes various degrees of damage to cholinergic neurons, depending on the quantity of the toxin that reaches the target tissue.     

Morphological study of fetal nasopharyngeal epithelium in man.

In 30 human fetuses between 8 and 13 weeks of intrauterine life the lateral wall of the nasopharynx was examined by light microscopy and transmission and scanning electron microscopy. In the subjects between 8 and 9 weeks in utero the mucosa displays still an immature appearance, being mono- or bistratified and lacking the characteristic structures of the respiratory epithelium. Nevertheless, signs of differentiation are to be noticed, with the presence of two distinct cellular types that, in the later periods, will give rise to ciliated cells and microvillus-provided cells. An almost complete differentiation will be reached at 12-13 weeks in utero, even if goblet cells are still lacking in the examined zone during the considered period. Nonrespiratory types of epithelium, such as transitional or squamous, were never found in the studied subjects.