Overexpression of a novel Xenopus rel mRNA gene induces tumors in early embryos.

The Rel family of transcriptional activators form a large diverse group of proteins that are involved in the activation of genes involved in immunity, development, apoptosis and cancer. So far, none of the rel genes cloned in mammals appear to be required for embryonic development. We have cloned and characterized a cDNA from an embryonic cDNA library that encodes a novel Xenopus Rel protein, called Xrel3. Xrel3 is a member of the cRel subfamily and is most closely related to but distinct from other Xenopus Rel members. The expression of Xrel3 mRNA was investigated using Northern analysis, RNase protection assay, reverse transcriptase-linked polymerase chain reaction and in situ hybridization. Messages are present maternally and are slightly enriched in the equatorial region of the blastula stage embryo. At gastrulation, the accumulation of Xrel3 messages declines to undetectable levels but then increases after neurulation. In situ RNA hybridization was used to determine the spatial location of Xrel3 messenger RNA in embryos. Messages are localized to the developing forebrain, dorsal mid-hindbrain region, the inner ear primordium, or otocyst, and in the notochord. Overexpression by microinjection of Xrel3 RNA induced tumors in the developing embryo that appeared after gastrulation. The location of the tumors depended on the location of the injection site. These results suggest that Xrel3 might have a generalized role in regulation of cell differentiation in the embryo.

Radiological features of a symptomatic splenic hamartoma.

Symptomatic splenic hamartomas are rare in the pediatric age group, with only four previous reports in the literature. Splenic hamartoma has been reported as a solid homogeneous mass without calcification on CT and ultrasound (US), and only one previous report of the findings on MRI has been published. We report a case of a large symptomatic splenic hamartoma in a 14-year-old girl who presented with splenomegaly, pancytopenia and growth retardation. A solid mass with multiple punctate foci resembling calcifications was seen on US. The mass was heterogeneous and better demarcated on enhanced CT. Radiocolloid scintigraphy demonstrated uptake within the lesion, but less than that of normal spleen. The mass was isointense relative to normal splenic tissue on T1-weighted MRI (0.5 T) and of increased intensity with T2 weighting. At splenectomy, a red pulp hamartoma was identified, which contained nodules of hyalinization and necrosis thought to account for the punctate foci seen on US.

Recovery of synergistic skeletal muscle function following ischemia.

This study tests the hypothesis that if the fast twitch muscles in a synergistic group were more susceptible to ischemia/reperfusion injury, then the slow twitch muscle would compensate functionally during recovery. Rat hindlimb fast twitch gastrocnemius and plantaris muscles and slow twitch soleus muscle were studied. In the experimental (E) group of rats, the right hindlimbs had 2 hr of pressure-controlled (300 mmHg) tourniquet ischemia. The masses and the maximal isometric tetanic forces of the three muscles were evaluated at 1, 3, 5, and 7 weeks in E (n = 24) and a control (C) group of rats (n = 24). Gastrocnemius mass and plantaris mass were both reduced (at 1, 3, and 5 weeks and at 1 and 3 weeks, respectively), whereas there were no significant changes in the mass of the soleus. The maximal isometric tetanic forces (N) measured at 1 week of recovery were reduced to 52, 53, and 67% of C values for the gastrocnemius, plantaris, and soleus, respectively. However, at 1 week the normalized isometric tetanic forces (N/g) for all three muscles were reduced to 66-69% of the C values. By Week 3, the tetanic forces (N or N/g) of all muscles had recovered to control values. On average, the gastrocnemius, plantaris, and soleus muscles of the C groups contributed 68, 24, and 8%, respectively, of the total synergistic tetanic force. These values were unaffected by ischemia. From this experiment, it is concluded that 2 hr of tourniquet ischemia resulted in a selective decrement in mass of the fast twitch muscles.(ABSTRACT TRUNCATED AT 250 WORDS)

Aerosol ventilation scintigraphy in the evaluation of bronchopleural fistula: a case report and literature review.

Radioaerosol scanning is simple to perform and is widely used in conjunction with perfusion imaging to detect pulmonary emboli. It may also be a valuable tool for the early diagnosis of postpneumonectomy bronchopleural fistula. The authors present an illustrative case in which radioactive aerosol imaging was used to confirm a bronchopleural fistula secondary to pneumonectomy for squamous cell carcinoma.

Treatment of canine embolic pulmonary hypertension with recombinant tissue plasminogen activator. Efficacy of dosing regimes.

We investigated effects of two dosing regimes of recombinant tissue plasminogen activator (rt-PA) and sodium heparin on pulmonary thrombolysis in a canine model of pulmonary hypertension, induced by injection of radioactive blood clots. By continuously counting over both lung fields with a mobile gamma camera, we correlated rate and extent of pulmonary thrombolysis with corresponding pulmonary hemodynamics. Treatment with heparin, over a 3-hour interval, did not result in significant thrombolysis or in a decrease in mean pulmonary artery pressure (PAP). In contrast, rt-PA caused marked pulmonary thrombolysis. While total clot lysis was similar when 1 mg/kg rt-PA was infused over 15 (rt-PA15) or 90 (rt-PA90) minutes (47% and 42%, respectively), rate of lysis during infusion was markedly increased with rt-PA15 (56% vs. 27%/hr, p less than 0.001). Corresponding to the increased rate of thrombolysis with rt-PA15, relative PAP decrease was greater at 15 and 30 minutes. At 4 hours, PAP decreased most with rt-PA90. However, two of the six dogs given rt-PA15 had an increase in PAP and lung radioactivity 1 hour after rt-PA. This was associated with dislodgment of a previously trapped clot. These results suggest that rt-PA may be appropriate therapy for pulmonary embolism and support further studies designed to optimize dosing regimes.