XR3054, structurally related to limonene, is a novel inhibitor of farnesyl protein transferase.

In this report, a novel inhibitor of farnesyl protein transferase (FPTase) is described. The compound, XR3054, is structurally similar to farnesol, a component of the reaction in which FPTase catalyses transfer of farnesol pyrophosphate to the CAAX recognition motif on proteins. The compound was selected initially because of its ability to inhibit in vitro farnesylation of CAAX recognition peptides with an IC50 of 50 microM. The farnesylation of p21 ras was reduced in a dose-dependent manner in the presence of XR3054. Similarly XR3054 was able to reduce the anchorage-independent growth of V12 H-ras transformed NIH 3T3 cells in a focus formation assay in soft agar, with an IC50 value of 30 microM, whilst not affecting the anchorage-independent growth of v-raf transformed cells. XR3054 reduced the phosphorylation of p42 mitogen activated protein (MAP) kinase in parental NIH 3T3 cells and V12 H-ras transformed NIH 3T3 cells, but constitutively active v-raf transformed cells showed no reduction in phosphorylation of ERK2 in the presence of XR3054. XR3054 inhibited the proliferation of the prostatic cancer cell lines LnCAP and PC3 and the colon carcinoma SW480 and HT1080 (IC50 values of 12.4, 12.2, 21.4 and 8.8 microM, respectively) but was relatively inactive when tested against a panel of breast carcinoma cell lines. The activity did not relate to the presence of mutant or wild-type ras in the cell lines tested. In conclusion XR3054 inhibits ras farnesylation, MAP kinase activation and anchorage-independent growth in NIH 3T3 transformed with v12 H-ras. Since the antiproliferative effect of the compound is not related to the ras phenotype, XR3054 may also have effects on other cell signalling mechanisms.

Pulmonary hypertension and right heart failure in patients with beta-thalassemia intermedia.

We analyzed seven patients with beta-thalassemia intermedia presenting with congestive heart failure secondary to pulmonary hypertension. This condition has been recognized only recently as part of the clinical spectrum of beta-thalassemia. Our group of patients included two men and five women with the clinical picture and laboratory data typical of beta-thalassemia intermedia. The mean age was 37.7 +/- 11.4 years, mean hematocrit value was 28.5 +/- 1.8%, mean number of transfused blood units was 171 +/- 153, and mean serum ferritin levels were 4,428 +/- 2,006 ng/mL. All but one of these patients had undergone splenectomy. Common findings of the investigative procedures include the following: dilation of the main pulmonary artery and cardiac enlargement in the chest radiograph; signs of right ventricular hypertrophy in the ECG; and dilated right ventricle with good left ventricular function in the echo study. Right heart catheterization showed the pulmonary systolic pressure to range from 55 to 90 mm Hg (74.1 +/- 10.3), pulmonary diastolic pressure from 25 to 50 mm Hg (37.7 +/- 8.7), mean pressure from 35 to 60 mm Hg (49.7 +/- 7.9), and pulmonary vascular resistance from 267 to 667 dynes.s.cm-5. Pulmonary capillary wedge pressure was within the normal range of values. The pathophysiologic condition of pulmonary hypertension in these patients is most probably associated with beta-thalassemia. There are mechanisms that increase cardiac output and at the same time restrict the pulmonary vascular bed. The results of this study imply that treatment decisions should be reconsidered for such patients.

[Kawasaki's disease in a young adult]. / Maladie de Kawasaki chez un adulte jeune.

The authors describe a 29-year-old white male who fulfilled the diagnostic criteria for Kawasaki disease. Apart from the patient's age, this case is unusual in that there were a large number of manifestations including liver complications, epistaxis, Baker's cyst, and circulating anti-neutrophil cytoplasmic antibodies.