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While many studies have investigated the overall nutritional status of children with cancer, the status with regard to vitamin B6 has not been investigated. Vitamin B6 is an important factor in over 100 different chemical reactions within cells. It has been hypothesized by some that abnormalities in vitamin B6 metabolism could play a role in the development of cancer. For this reason, the vitamin B6 status was investigated in 37 children with leukemia and in 37 age-matched controls. The study examined the plasma levels of pyridoxal 5'-phosphate (PLP), which is the biologically active form of the vitamin; it is generally believed that the circulating plasma levels of this vitamin are a fair indication of the total body store. It was found that the patients generally had significantly lower levels of PLP than the control subjects, although not all the leukemia patients were below the normal range. However, a low level of a vitamin in a cancer patient does not mean that a low level contributed to the development of the disease. While some experiments in animals have indicated that vitamin B6 deprivation can contribute to the development of cancer, there is no reason to think that the children studied in the present research were deprived prior to the development of their disease. Testing of the siblings of these patients did not reveal any abnormalities, and it seems likely that the depressed levels of vitamin B6 observed in these patients are a result of inadequate nutrition resulting from cancer, rather than a contributing cause. However, it cannot be ruled out that at least some of the observed reduction in circulating vitamin B6 may result from the increased use of the vitamin by the leukemic cells themselves. Therefore, the possibility that any supplementation of the diets of these children with vitamin B6 may actually provide the cancer cells with more of what they need to grow must be considered. More must be learned about the metabolism of vitamin B6 in leukemic children before guidelines for vitamin supplementation are developed. (Consumer Summary produced by Reliance Medical Information, Inc.)

Genes expressed specifically in a tissue are often involved in the defining functions of that tissue. We used representational difference analysis of cDNA to amplify 20 cDNA fragments representing transcripts that were more abundant in the lobster olfactory organ than in brain, eye/eyestalk, dactyl, pereiopod, or second antenna. We then independently confirmed that the transcripts represented by these clones were enriched in the olfactory organ. The 20 cDNA fragments represent between 6 and 15 different genes. Six of the cDNAs contained sequences highly similar to known gene families. We performed in situ hybridization with these six and found that all were expressed in subsets of cells associated with the aesthetasc sensilla in the olfactory organ. Clones OET‐07, an ionotropic receptor, and OET‐10, an α tubulin, were specific to the olfactory receptor neurons. OET‐02, a monooxygenase, was expressed only in the outer auxiliary cells. OET‐03, a serine protease, was specific to the collar cells. OET‐11, an α2macroglobulin, was expressed by the receptor neurons and the collar cells. OET‐17, a calcyphosine, was expressed in the receptor neurons, inner auxiliary cells, and collar cells. The identities and expression patterns of these six transcripts predict involvement in both known and novel properties of the lobster olfactory organ. J. Comp. Neurol. 455:125–138, 2003. © 2002 Wiley‐Liss, Inc.

Hollins, Bettye and Stephen R. Ikeda.Heterologous expression of a P2x-purinoceptor in rat chromaffin cells detects vesicular ATP release. J. Neurophysiol.78: 3069–3076, 1997. A cloned P2x-purinoceptor was transiently expressed in single isolated rat adrenal chromaffin cells and evaluated for the detection of released ATP. After cytoplasmic injection of the P2xcomplementary RNA (cRNA; 4–24 h), application of ATP produced an inwardly rectifying current over the voltage range −130 to −10 mV as measured by the whole cell patch-clamp technique. The dose-response curve for ATP was sigmoidal with a 50% effective concentration of 18.2 μM. Suramin, a P2x-antagonist, attenuated the ATP-induced current. Depolarizing voltage pulses to 0 mV or application of histamine, stimuli that trigger exocytosis, resulted in the appearance of suramin-sensitive spontaneous transient inward currents (at −60 mV) that resembled excitatory postsynaptic currents although they were slower in time course. Concurrent detection of catecholamine release with a carbon fiber electrode often showed coincidence of the amperometric current with the synaptic currentlike events suggesting that ATP and catecholamines were released from the same vessicle. These data demonstrate that expression of a P2x-purinoceptor in chromaffin cells produces a functional autoreceptor capable of detecting vesicular release of ATP. In combination with carbon fiber amperometry, simultaneous vesicular release of two neurotransmitters from a single chromaffin cell could be monitored. The P2x-purinoceptor, however, produced a regenerative effect on release apparently resulting from the high Ca2+permeability of the receptor. Thus modification of the P2x-purinoceptor would be required before the system could be applied to examining processes involved in stimulus-release coupling.