Background: Terminal deoxynucleotidyltransferase (TdT) is a DNA polymerase that enhances Ig and TcR gene diversity in the N region in B-and T-cells. TdT is found as a member of a large protein complex in the lysate of the thymocytes. To elucidate the molecular mechanism of the synthesis of the N region, we first attempted to isolate the genes with products that are interacting directly with TdT.

Passing galvanic current across the skin (known as "tap water iontophoresis" or TWI) inhibits sweating; however, its mechanism of action is unclear. Using improved methods, we confirmed that anodal current has more of an inhibitory effect than cathodal current, water is superior to saline, and the inhibitory effect is a function of the amperage used. To address the importance of current flowing through the pores, a layer of silicone grease was placed on the skin to reduce the shunt pathway across the epidermis. With silicone, total skin conductance decreased 60% without the sweat pores being occluded, swelling of the stratum corneum and collapse of the poral lumen was prevented, and current-induced inhibition of sweating was enhanced, most likely because of an increase in current density in the pores. The pH of anodal water, but not of saline, dropped to 3, whereas that of cathodal water increased to 10 during passage of current through the skin. Acidified anodal water was superior to alkaline water. Sweat glands isolated from TWI-induced anhidrotic palmar skin responded to methacholine in vitro, but the sweat rate and pharmacological sensitivity were slightly lowered. Thus the strong acidity generated by hydrolysis of water in the anodal bath and the further accumulation of H+ in the sweat duct by anodal current may be responsible for TWI-induced inhibition of sweating due to an unknown lesion(s) in the duct or sweat pore. The secretory coil function may also be altered because of exposure to intense acidity during TWI. The importance of H+ movement into the sweat pore for inhibition of sweating could be further exploited to develop new strategies for the control of sweating.

Background: The repertoires of Ig and TcR are generated by a combinatorial rearrangement of variable (V), diversity (D), and joining (J) segments (V(D)J recombination) in B-and T-cells. Terminal deoxynucleotidyltransferase (TdT) adds extra nucleotides (N nucleotides) at the junctions of the gene segments to enhance the Ig and TcR genes diversity. Using an antiTdT antibody column, TdT has been purified as a member of a megadalton protein complex from rat thymus. The N region would be synthesized with the large protein complex.

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In freshly dissociated rhesus palm eccrine clear cells, regulatory volume increase (RVI) was studied using image analysis as a measure of Na-K-2Cl cotransport activity. Pseudo-RVIs, as well as RVI during methacholine (MCh)-induced cell shrinkage, were observed in clear cells and were inhibited by 100 microM bumetanide or in Na-free medium, but were not inhibited by amiloride or ouabain. RVI in hypertonic medium and RVI after MCh-induced cell shrinkage were accelerated by adenosine 3',5'-cyclic monophosphate (cAMP)-elevating agents (forskolin+isoproterenol) and inhibited by phorbol ester. RVI in hypertonic medium was enhanced by a phosphatase inhibitor, okadaic acid. mRNA for Na-K-2Cl cotransporter (NaKCC) was demonstrated in freshly isolated rhesus sweat secretory coils by polymerase chain reaction (PCR) after reverse transcription using a set of primers derived from the published human NaKCC (hNaKCC) 1 sequence, i.e., nucleotides 2,043-2,810. The deduced amino acid sequence of the PCR-amplified 767-base pair segment was identical to that of hNaKCC 1 from a human colon cell line (T84). The data are interpreted to indicate that NaKCC, showing strong homology to secretory type hNaKCC 1, is present in rhesus eccrine secretory coils and may participate in the cotransport component of eccrine sweat secretion and cell volume regulation, especially during cholinergic stimulation. The data also raise the possibility that sweat gland NaKCC may be upregulated by cAMP-mediated protein phosphorylation and downregulated by protein kinase C.