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M Deen

Publications and source records attributed to M Deen.

9 recordsLinked to original sources
PubMed1999

The destabilization of IL-2 mRNA by a premature stop codon and its differential stabilization by trans-acting inhibitors of protein synthesis do not support a role for active translation in mRNA stability.

To investigate the role that translation plays in the stabilization of the IL-2 mRNA, we inhibited protein synthesis in both cis and trans. To block translation in trans, we utilized the inhibitors puromycin (PUR) and cycloheximide (CHX), which differentially effect polysome structure. We found that CHX enhances the stability of IL-2 mRNA in cells stimulated with anti-TCR Ab alone, but it inhibits CD28-induced message stabilization in costimulated cells. In contrast, PUR had a minimal effect on IL-2 mRNA stability in either the presence or absence of costimulation. The differential effects of these two inhibitors suggest that: 1) CHX is unlikely to stabilize the IL-2 mRNA by inhibiting the expression of a labile RNase; 2) CD28-mediated IL-2 mRNA stabilization does not require translation; and 3) IL-2 mRNA decay is not coupled to translation. To block translation in cis, we generated sequence-tagged IL-2 genomic reporters that contain a premature termination codon (PTC). In both the presence and absence of costimulation, these PTC-containing mRNAs exhibit drastically diminished stability. Interestingly, the addition of CHX but not PUR completely restored CD28-mediated stabilization, suggesting that CHX can block the enhanced decay induced by a PTC. Finally, CHX was able to superinduce IL-2 mRNA levels in anti-TCR Ab-stimulated cells but not in CD28-costimulated cells, suggesting that CHX may also act by other mechanisms.

Animals↗
PubMed1999

CD28-Mediated regulation of mRNA stability requires sequences within the coding region of the IL-2 mRNA.

Using sequence-tagged genomic reporter constructs, we investigated the contribution of IL-2 sequences to CD28-mediated regulation of mRNA stability. We find that CD28 signaling acts transiently to stabilize the IL-2 mRNA following T cell activation. Such stabilization requires sequences within both exon 2 and the coding region of exon 4. Unexpectedly, CD28 signaling at later times enhances the decay of the IL-2 mRNA. This CD28-dependent decay of IL-2 mRNA requires sequences localized between exon 3 and the stop codon. Our findings demonstrate that the coding region of the IL-2 mRNA contains previously undefined CD28-responsive sequence elements that are critical for the regulation of mRNA stability.

3' Untranslated Regions↗
PubMed1991

[Pelvic lipomatosis. A case with ureteral and venous obstruction].

The authors report a case of pelvic lipomatosis in a 62 year old man associated with venous obstruction (third case reported in the literature), diagnosed after bilateral ureteric obstruction, and review of the literature on this subject. The diagnosis was suggested by the radiological triad of hyperlucency of the pelvis on plain abdominal X-ray, "hot air balloon" appearance of the bladder on IVU and a rigid and ascended rectosigmoid on barium enema, and was confirmed by CT and MRI. Treatment combining corticosteroids and urinary tract disinfection was partially effective. A double J ureteric stent resolved the problem of persistent right ureteric obstruction.

Cystoscopy↗
PubMed1990

[Contusions of the liver in adults. Initial non-operative management with computerized tomography follow-up is a reasonable therapeutic option. Report of 16 cases].

Nonoperative management of blunt liver injury in adults still remains controversial. From February 1985 through September 1989, 27 patients were treated for blunt hepatic trauma: 11 required immediate operation and 16 (59%) were initially managed nonoperatively after evaluation of intraabdominal injury by computerized tomography. All of these 16 patients were hemodynamically stable and had no significant peritoneal signs. CT criteria for nonoperative management included subcapsular and intrahepatic hematoma, capsular tear or unilobar fracture, absence of large hemoperitoneum, absence of large devitalized liver and absence of other intraabdominal organ injuries. Clinical follow-up, repeated radiologic examinations and surgery confirmed the accuracy of CT. Only 2 patients required delayed operation (12.5%). Serial abdominal CT studies are an integral part of the conservative treatment of blunt hepatic injuries and showed complete resolution of hepatic injuries in the fourteen nonoperated patients in less than six months. No death and no delayed septic or biliary complications were noted. Mean hospital stay was seventeen days for all of the patients (multiple injuries or not) and only ten days for isolated blunt liver injury. These good results depend on identification of candidates for nonoperative management on strict clinical and CT criteria. Nonoperative management of adult blunt liver injury based on these findings is a useful alternative in a selected group of hemodynamically stable patients and decreases the rate of non-therapeutic coeliotomy.

Adult↗
PubMed1988

Pulmonary endocrine cells in various species in the Himalaya.

The numbers, morphology and distribution of pulmonary endocrine cells in goats, sheep and the yak and its interbreeds with cattle, dzos and stols, were studied after their demonstration by means of the peroxidase-antiperoxidase technique with a polyclonal antiserum raised in the rabbit to human neuron-specific enolase, a marker for neuroendocrine cells. The numbers, morphology and distribution were related to species and not to residence at high altitude. Pulmonary endocrine cells were common and mainly distributed as solitary cells in the epithelium of the bronchial tree in sheep. They were much less common and found mainly as clusters in the alveolar capillary walls in goats and in the yak and its interbreeds with cattle.

Altitude↗