Novel alternative splicing predicts a secreted extracellular isoform of the human receptor-like protein tyrosine phosphatase LAR.

RT-PCR was used to examine the expression of LAR (encoding the leukocyte-common antigen-related protein tyrosine phosphatase) in normal human colon mucosa, and colon polyps and tumors. Although the LAR protein was not detected in the colon in a previous immunohistochemical study, amplification of a region of LAR between the most membrane proximal (eighth) fibronectin type-III (FN-III) repeat and the transmembrane domain demonstrated LAR expression in all samples, but showed no difference in expression within matched samples from each patient examined. An additional minor fragment amplified in all reactions was consistently observed in colon and various cell line samples using this and two other LAR-specific sets of primers. Cloning and sequencing of the fragment identified it as deriving from a novel alternatively spliced form of LAR containing a retained intron of 85 bp. This intron encodes an additional 13 amino acids followed by an in-frame stop codon, thus its retention is predicted to give rise to a secreted LAR extracellular region isoform(s). LAR transcripts containing the intron were detected by RNase protection assay of colon samples and were present in most human tissues examined by Northern analysis. A protein in colon tumor extract was recognized by antiserum raised to the intron-encoded sequence. Soluble isoforms of the LAR extracellular immunoglobulin (Ig)-like/FN-III repeat-containing region could have a biological function distinct from those isoforms localized at the cell surface and/or coupled to intracellular phosphatase activity.

Single-blind comparative analgesic and safety study of single doses of intramuscularly administered ketorolac tromethamine and pethidine hydrochloride in patients with pain following orthopaedic surgery.

Ketorolac tromethamine, a potent non-narcotic prostaglandin synthetase inhibiting analgesic was compared with pethidine for relief of moderate to severe postoperative pain. Forty-eight patients received Ketorolac 0.5 mg/kg and 52 received pethidine 1.25 mg/kg. The degree of pain prior to the administration of the drug and pain relief that followed were quantified using a vertical visual analogue scale (VAS) and monitored at hourly intervals. The safety profile was also studied by recording all adverse events noted. The mean pain (VAS) score at medication for Ketorolac was 7.04 and for pethidine 7.09. The pain relief obtained in the first four hours following administration of the drugs was similar for pethidine and Ketorolac. Although Ketorolac showed a longer sustained pain relief, time to peak analgesia after administration of this drug was slower than that after pethidine. It took 30 to 50 min for pethidine compared to 75 to 150 min for Ketorolac to achieve peak analgesia. The latter is therefore inappropriate if rapid pain relief is required. The incidence of side effects was significantly greater with pethidine (40.4%) as compared to Ketorolac (10.4%). The similar analgesic efficacy to pethidine makes Ketorolac an appropriate drug for the relief of postoperative pain especially in day surgery settings where observation following administration of the drug as in the case of pethidine can be dispensed with and patients sent home earlier because of the minimal side effects associated with its use. Caution must be exercised with the use of large doses of Ketorolac especially if the drug is used for more than 5 days to avoid serious complications like renal failure and gastrointestinal bleeding.