Ring-14 and trisomy 14q in the same child

The case of a male child with three cell lines is described: one cell line with ring chromosome 14, another trisomic for 14q, due to a derived metacentric 14q;14q, and a third one with a normal male karyotype. The clinical findings are compatible with those of the r(14) syndrome.     

New data on clonal anomalies of chromosome 14 in ataxia telangiectasia: tct (14;14) and inv(14)

Summary From a series of 53 patients with ataxia telangiectasia, two large clones with a t tan or tct(14;14) and two with an inv(14) were observed among phytohaemagglutinin (PHA)-stimulated lymphocytes. Smaller clones with the same inv(14) were observed in two other cases. Similar breakpoints may exist, both for t(14;14) and inv(14): q11.1/q11.2 and q32, and it is postulated that the rearrangements are related to a recombination of the -chain of the T-cell receptor and IgH clusters of genes.     

Assimilative Pathway of Methanol in Candida sp. Incorporation of 14C-Methanol, 14C-Formaldehyde, 14C-Formate and 14C-Bicarbonate into Cell Constituents

1. The incorporation of ¹⁴C-methanol, ¹⁴C-formaldehyde, ¹⁴C-formate and ¹⁴C-bicarbonate into a methanol-utilizing yeast, Candida N–16, was examined by paper-chromato-graphy and radioautography.

2. At the earliest time period examined, the highest percentage of radioactivity fixed from ¹⁴C-methanol or ¹⁴C-formaIdehyde into methanol-grown cells was found in fructose phosphate. The percentage distribution of radioactivity in fructose phosphate decreased as time elapsed. The radioactivity fixed from these compounds into glucose-grown cells was negligible compared with that fixed into methanol-grown cells.

3. The incorporation of ¹⁴C-formate into methanol-grown cells was extremely low. The highest percentage of radioactivity fixed for short time incubation was found in serine. The incorporation pattern of glucose-grown cells was similar to that of methanol-grown cells.

4. At the earliest time period, over 70% of radioactivity fixed from ¹⁴C-bicarbonate into methanol- or glucose-grown cells was found in aspartate.

5. These results suggest that in Candida N–16 methanol is specifically assimilated by a route with hexose phosphate as a primary stable intermediate.

     

Comparative diffusion of 14C-ethionine and 14C-methionine in rat tissue]

The pancreas is the tissue which traps the most intensively the trace-dosis injected ethionine -14C; 30 min after the injection, the pancreas fixes the labelled product twice more than the liver and five times more than the stomach. This trapping might explain the pancreatic modifications occuring during the intoxication. In the same experimental conditions, the pancreas fixes the ethionine -14C twice less than methionine. Urinary excretion of ethionine is faster and more important than that of methionine.     

A 14/14 marker chromosome lymphocyte clone in ataxia telangiectasia.

A lymphocyte clone with a 45, XY karyotype with a 14/14 tandem translocation marker, the frequency of which is time-variable, has been observed in an ataxia telangiectasia patient. Cells with the marker chromotosome were not observed in fibroblasts cultures derived from a skin biopsy, nor was the marker observed in leukocyte cultures from the patient's two affected sibs.     

Trisomy 14 in spontaneous abortus

Summary Chromosome analysis of the amnion from a spontaneous abortus revealed a 47,XX,D+karyotype. Giemsa banding pattern technique identified the extra chromosome as a No. 14.

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Zusammenfassung Die Chromosomenanalyse der Amnionzellen eines Spontanaborts zeigte einen Karyotyp 47,XX,D+. Mit der Giemsamusterfärbung wurde das Extrachromosom als Nr. 14 identifiziert.

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This study was supported by the Ford Foundation Population Program, Grant No. 640-0411B and by the World Health Organisation.     

14CO2 Assimilation and 14C-photosynthate Translocation in Different Leaves of Sunflower

Chlorophyll and nitrogen contents were highest in leaves of middle position, similarly as photosynthetic efficiency represented by ¹⁴C fixation (maxima in leaf 5 from the top). All the leaves lost ¹⁴C after 2 weeks of ¹⁴CO₂ exposure. However, the reduction in radioactivity was less in young upper leaves than in the mature lower leaves. Leaves exported ¹⁴C-photosynthates to stem both above and below the exposed leaf. Very little radioactivity was recovered from the seeds of plants in which only first or second leaves were exposed to ¹⁴CO₂ implying thereby that the carbon contribution of first two leaves to seed filling was negligible. The contribution of leaves to seed filling increased with the leaf position up to the sixth leaf from the top and after the seventh leaf their contribution to seed filling declined gradually.     

Metabolism of phytol-U-14C and phytanic acid-U-14C in the rat

The metabolism of uniformly-labeled (14)C-phytol, (14)C-phytenic acid, and (14)C-phytanic acid was studied in the rat. Conversion of both phytol and phytenic acid to phytanic acid was demonstrated. Tracer doses of phytol-U-(14)C given orally were well absorbed (30-66%), and approximately 30% of the absorbed dose was converted to (14)CO(2) in 18 hr. After intravenous injection, 20% appeared in (14)CO(2) in 4 hr. Phytanic acid-U-(14)C given intravenously was oxidized at a comparable rate (22-37% in 4 hr) and was as rapidly oxidized as palmitic acid-1-(14)C (21% in 4 hr). Metabolism of these substrates was also studied in rats previously maintained on a diet containing 5% phytol by weight, which causes accumulation of phytanic acid, phytenic acid, and, to a lesser extent, phytol in blood and tissues. Despite the large body pools of preformed, unlabeled substrate in these animals, the fraction of an administered dose of phytol-U-(14)C or phytanic acid-U-(14)C converted to (14)CO(2) was not significantly diminished. These studies indicate that the rat has an appreciable capacity to degrade the highly branched carbon skeleton of phytol and its derivatives. Twenty-four hours after administration of phytol-U-(14)C, the lipid radioactivity remaining in the body was widely distributed among the tissues, highest concentrations being found in liver and adipose tissue. Four hours after intravenous administration of phytanic acid-U-(14)C, all of the major lipid classes in the liver contained radioactivity, most in triglycerides and phospholipids and least in cholesterol esters and lower glycerides. There was no demonstrable incorporation of mevalonate-2-(14)C or acetate-1-(14)C into liver phytanic acid when they were given intravenously to a rat previously fed phytol. Endogenous biosynthesis, if it occurs at all, must be extremely limited.     

14C] GABA and [14C]GABA-pantoyl metabolism in mice

It is shown that more than 90% of the labelled substance D-[1-14C] calcium homopantotenate is rapidly removed from the organism with urea; 6-8% are products of its transformation, among them GABA is identified. An insignificant transformation of D-[1-14C] calcium homopantotenate up to 14CO2 is observed. After the preparation administration only unchanged D-[1-14C] calcium homopantotenate was found in the tissues, except of the liver where, as in urea, there is a nonidentified product with small Rf. [1-14C] GABA is rapidly transformed to 14CO2 and only its insignificant part is removed with urea, chiefly as products of transformation.     

The chromosome breakpoint at 14q32 in an ataxia telangiectasia t(14;14) T cell clone is different from the 14q32 breakpoint in Burkitts and an inv(14) T cell lymphoma

Summary The T cell receptor chain gene locus and the immunoglobulin heavy chain gene locus (IgH) have previously been mapped to the q11 and q32 positions respectively of the human chromosome 14. Both of these sites are also common breakpoints in lymphocytes from ataxia telangiectasia (A-T) patients. Using in situ hybridisation we show that the 14q32 breakpoint in an A-t non-leukaemic T cell clone with t(14;14) translocation, lies outside the IgH locus and proximal to it with respect to the centromere. The 14q11-14qter segment of the homologous chromosome 14 carrying the constant gene region of the chain locus is translocated to this 14q32 position.