The sequences of three cDNA clones that include the complete coding region of hydroxycinnamoylCoA:tyramine N-hydroxycinnamoyltransferase (THT) from tobacco are reported. The three cDNAs were isolated by antibody screening of a cDNA expression library produced from poly(A) + RNA purified from tobacco leaves (Nicotiana tabacum cv. Bottom Special), previously infiltrated with an incompatible strain of Ralstonia solanacearum. The identity of these clones was confirmed by the detection of THT activity in extracts of transformed Escherichia coli and by matching the translated polypeptides with tryptic enzyme sequences. cDNA clones tht4 and tht11 differ only by their 5 H leader and 3 H UTRs and therefore encode the same protein, whereas tht10 and tht11 exhibit 95 and 99% sequence identity at the DNA and deduced amino acid levels, respectively. The three clones encode proteins of 226 amino acids with calculated molecular masses of 26 kDa. The deduced amino acid sequences show no similarity with the sequence of anthranilate hydroxycinnamoyl/benzoyltransferase from Dianthus caryophyllus, the only enzyme exhibiting hydroxycinnamoyltransferase activity to be cloned so far in plants. In contrast, comparison of the THT amino acid sequence with protein sequence databases revealed substantial homology with mammalian diamine acetyltransferases. The THT clones hybridized to a 0.95-kb mRNA from elicited tobacco cell-suspension cultures and also to a mRNA of similar size from wound-healing potato tubers. The messengers for THT were also found to be expressed at relatively high levels in tobacco root tissues. Southern hybridization of tobacco genomic DNA with THT cDNA suggests that several copies of the THT gene occur in the tobacco genome. Inhibition experiments using amino-acid-specific reagents demonstrated that both histidyl and cysteyl residues are required for THT activity. In the course of these experiments THT was also found to be inhibited by (2-hydroxyphenyl) amino sulfinyl acetic acid 1,1-dimethylethyl ester, an irreversible inhibitor of cinnamyl alcohol dehydrogenase.

Cocaine has been associated with known adverse effects on cardiac, cerebrovascular and pulmonary systems. However, the effect of cocaine on other organs has not been extensively reported. A middle age man presented with abdominal pain and nausea after inhalation of crack cocaine. On admission, he was found to be hypertensive and tachycardic. Physical examination revealed mild abdominal tenderness without rebound. Laboratory investigations were significant for acute kidney failure with elevated serum creatinine (3.72 mg/dL), thrombocytopenia (platelet count 74,000/UL), elevated alanine and aspartate transaminases (ALT 331 U/L; AST 462 U/L) and elevated creatine phosphokinase (CPK 5885 U/L). Urine toxicology screening solely revealed cocaine. A clinical diagnosis of cocaine toxicity was made and patient was admitted to the intensive care unit because of multi organ failure. Despite downward trending of liver enzymes during the hospital course, he continued to have residual renal insufficiency and a low platelet count at the time of discharge. In a patient with history of recent cocaine use presenting with these manifestations, cocaine itself should be considered as a likely cause.

No abstract

No abstract