Reverse transcriptase pancreatic

RNA to initiate cDNA synthesis. All cellular mRNA contains multiple repeats of adenine bases (poly-A tails). Therefore the complementary thymine bases (oligo-dT) can be used as a primer that binds to the mRNA template required for the reverse transcriptase to synthesize the cDNA. In the case of pancreatic mRNAs (Figure 4.2), the signihcantly higher mRNA for insulin compared with other proteins allowed success in isolating the insulin-specihc cDNA. Subsequent insertion of cDNA into a bacterial expression vector allowed the production of functional insulin that is now marketed as a successful therapeutic product (Figure 4.2). 

Recently, lamivudine [LAM ih vue deen] or (-)-2 -deoxy-3 -thiacyti-dine (3TC) has been approved for treatment of HIV in combination with zidovudine. This dideoxynucleoside terminates the synthesis of the proviral DNA chain and also inhibits reverse-transcriptase of both HIV and hepatitis B virus (HBV). However, it does not affect mitochondrial DNA synthesis or bone marrow precursor cells. Resistance to zidovudine develops more slowly with the combination. Lamivudine has good bioavailability on oral administration and depends on the kidney for excretion. Though generally well tolerated, pancreatitis develops in a significant number of pediatric... 

NUCLEOSIDE REVERSE TRANSCRIPTASE INHIBITORS RIBAVIRIN 1. t side-effects, risk of lactic acidosis, peripheral neuropathy, pancreatitis, hepatic decompensation, mitochondrial toxicity and anaemia with didanosine and stavudine 2.1 efficacy of lamivudine 1. Additive side-effects t intracellular activation of didanosine and stavudine 2. J intracellular activation of lamivudine 1. Not recommended. Use with extreme caution monitor lactate, LFTs and amylase closely. Stop co-administration if peripheral neuropathy occurs. Stavudine and didanosine carry a higher risk 2. Monitor HIV RNA levels if they T, review treatment combination... 

Lamivudine (3TC) is a reverse transcriptase inhibitor with a relatively long intracellular half-life (14 h plasma t 6 h). In combination with zidovudine, lamivudine appears to reduce viral load effectively and to be well tolerated, although bone marrow suppression may be produced. Rarely, pancreatitis may occur. Lamivudine has also been used for treatment of chronic hepatitis B infection, but resistant strains of virus have been reported. 

Table 5. Inhibition of reverse-transcriptase activity of FL-virions by distamycin derivatives in the absence of exogenous template. Virions containing Triton were preincubated at room temp, for 25 min with 50 jUg/ml of pancreatic RNase Chandra et al.6 ...

Papotti M, Bongiovanni M, Volante M, et al. Expression of somatostatin receptor types 1-5 in 81 cases of gastrointestinal and pancreatic endocrine tumors. A correlative immunohistochemical and reverse-transcriptase polymerase chain reaction analysis. Virchows Arch. 2002 440 461-475. 

Pancreatic dysfunction, heralded by large increases in serum amylase and lipase, is associated with the use of several reverse-transcriptase inhibitors (RTIs). Didanosine appears to be the worst offender, and pancreatitis is the most characteristic adverse effect of this particular NRTI. Conditions enhancing susceptibility to drug-induced pancreatic dysfunction include hypertriglyceridemia, hypercalcemia, and history of excessive ethanol use. Liver dysfunction including hepatitis may occur with the antitu-bercular drugs, isoniazid, and pyrazinamide. Cholestasis is associated with the estolate form of erythromycin. 

In the initial management of this patient, two nucleoside reverse transcriptase inhibitors (NRTIs) were administered. Hematologic suppression is a major adverse effect of zidovudine, while peripheral neuropathy and pancreatitis are important toxicities of didanosine. The gastrointestinal symptoms, together with the elevated amylase levels, were the reasons for discontinuance of didanosine and the substitution of another nucleoside reverse transcriptase inhibitor (lamivudine) in the drug regimen. See answer to question 3, above. 

Antiviral nucleoside inhibitor of HIV reverse transcriptase (NRTI). Used in combination regimens. Tox peripheral neuropathy, pancreatitis. Other NRTIs latnivudine (3TC), stavudine (d4T), zalcitabine (ddC), and the prototype, zidovudine (see below). 

PACAP is the newest member of the vasoactive intestinal peptide (VIP)/glucagon/secretin family. It is released from nerves, although their location in the gastrointestinal tract is not known. The PACAP receptor exists as several splice variants, and PACAP stimulates Ca signaling in pancreatic adnar cells, showing that this receptor is coupled to both adenylate cyclase and phospholipase C. PACAP stimulates caldum signals and histamine release from the ECL cell. Several variants of this receptor have been shown to be present by reverse transcriptase-polymerase chain reaction (RT-PCR) of an ECL cell cDNA library. 

---