Germline mutations of the fumarate hydratase (FH, fumarase) gene are found in the recessive FH deficiency syndrome and in dominantly inherited susceptibility to multiple cutaneous and uterine leiomyomatosis (MCUL). We have previously reported a number of germline FH mutations from MCUL patients. In this study, we report additional FH mutations in MCUL and FH deficiency patients. Mutations can readily be found in about 75% of MCUL cases and most cases of FH deficiency. Some of the more common FH mutations are probably derived from founding individuals. Protein-truncating FH mutations are functionally null alleles. Disease-associated missense FH changes map to highly conserved residues, mostly in or around the enzyme's active site or activation site; we predict that these mutations severely compromise enzyme function. The mutation spectra in FH deficiency and MCUL are similar, although in the latter mutations tend to occur earlier in the gene and, perhaps, are more likely to result in a truncated or absent protein. We have found that not all mutation-carrier parents of FH deficiency children have a strong predisposition to leiomyomata. We have confirmed that renal carcinoma is sometimes part of MCUL, as part of the variant hereditary leiomyomatosis and renal cancer (HLRCC) syndrome, and have shown that these cancers may have either type II papillary or collecting duct morphology. We have found no association between the type or site of FH mutation and any aspect of the MCUL phenotype. Biochemical assay for reduced FH functional activity in the germline of MCUL patients can indicate carriers of FH mutations with high sensitivity and specificity, and can detect reduced FH activity in some patients without detectable FH mutations. We conclude that MCUL is probably a genetically homogeneous tumour predisposition syndrome, primarily resulting from absent or severely reduced fumarase activity, with currently unknown functional consequences for the smooth muscle or kidney cell.

Seliciclib (CYC202; R-roscovitine) is the first selective, orally bioavailable inhibitor of cyclin-dependent kinases 1, 2, 7 and 9 to enter clinical trial. Preclinical studies showed antitumour activity in a broad range of human tumour xenografts. A phase I trial was performed with a 7-day b.i.d. p.o. schedule. Twenty-one patients (median age 62 years, range: 39 -73 years) were treated with doses of 100, 200 and 800 b.i.d. Dose-limiting toxicities were seen at 800 mg b.i.d.; grade 3 fatigue, grade 3 skin rash, grade 3 hyponatraemia and grade 4 hypokalaemia. Other toxicities included reversible raised creatinine (grade 2), reversible grade 3 abnormal liver function and grade 2 emesis. An 800 mg portion was investigated further in 12 patients, three of whom had MAG3 renograms. One patient with a rapid increase in creatinine on day 3 had a reversible fall in renal perfusion, with full recovery by day 14, and no changes suggestive of renal tubular damage. Further dose escalation was precluded by hypokalaemia. Seliciclib reached peak plasma concentrations between 1 and 4 h and elimination half-life was 2 -5 h. Inhibition of retinoblastoma protein phosphorylation was not demonstrated in peripheral blood mononuclear cells. No objective tumour responses were noted, but disease stabilisation was recorded in eight patients; this lasted for a total of six courses (18 weeks) in a patient with ovarian cancer.

Past studies have demonstrated that single nucleotide polymorphisms (SNPs) of the sodium-bicarbonate co-transporter gene (SLC4A5) are associated with hypertension. We tested the hypothesis that SNPs in SLC4A5 are associated with salt-sensitivity of blood pressure (BP) in 185 Caucasians consuming an isocaloric constant diet with a randomized order of 7 days low Na+ (10 mmol/d) and 7 days high Na+ (300 mmol/d) intake. Salt-sensitivity was defined as a ≥7mm Hg increase in mean arterial pressure (MAP) during a randomized transition between high and low Na+ diet. A total of 35 polymorphisms in 17 candidate genes were assayed, 25 of which were tested for association. Association analyses with salt-sensitivity revealed three variants that associated with salt-sensitivity, two in SLC4A5 (P <0.001), and one in GRK4 (P = 0.020). Of these, two SNPs in SLC4A5 (rs7571842 and rs10177833) demonstrated highly significant results and large effects sizes, using logistic regression. These two SNPs had P values of 1.0×10−4 and 3.1×10−4 with odds ratios of 0.221 and 0.221 in unadjusted regression models, respectively, with the G allele at both sites conferring protection. These SNPs remained significant after adjusting for BMI and age, (P = 8.9×10−5 and 2.6×10−4 and odds ratios 0.210 and 0.286, respectively). Further, the association of these SNPS with salt-sensitivity was replicated in a second hypertensive population. Meta-analysis demonstrated significant associations of both SNPs with salt-sensitivity [rs7571842 (P=1.2×10−5); rs1017783 (P=1.1×10−4)]. In conclusion, SLC4A5 variants are strongly associated with salt-sensitivity of BP in two separate Caucasian populations.

Purpose: A major mechanism of resistance to temozolomide involves the DNA repair protein O 6 -alkylguanine-DNA-alkyltransferase (ATase). The main aims of this phase I trial were to determine an ATase-depleting dose (ADD) of lomeguatrib, a potent pseudosubstrate inhibitor, and to define a suitable dose of temozolomide to be used in combination with lomeguatrib in patients with advanced cancer. Experimental Design: Lomeguatrib was administered at dose levels of 10 to 40 mg/m 2 days 1to 5, as a single agent, and also in combination with temozolomide. Once theADD of lomeguatrib was identified, the dose of temozolomide in combination was increased, in successive patient cohorts, from 50 to 175 mg/m 2 on days 1to 5 of a 28-day cycle to define the maximal tolerated dose and dose-limiting toxicity of the combination. Results: Thirty-eight patients with advanced solid tumors were enrolled. More than 95% ATase depletion within 4 hours of the first dose was achieved in peripheral blood mononuclear cells at lomeguatrib doses of z10 mg/m 2 /d i.v. or z20 mg/m 2 /d orally, and tumor biopsies showed z92% ATase depletion. At the ADD of lomeguatrib i.v., the maximal tolerated dose of temozolomide in combination was 150 mg/m 2 days 1to 5. The dose limiting toxicity of the combination of lomeguatrib and temozolomide was myelosuppression. The toxicity of lomeguatrib alone was minimal. In 23 patients with measurable disease, one complete response was seen and12 patients had stable disease for at least 3 months. Conclusion:This first administration of lomeguatrib to man successfully established an oral ADD of lomeguatrib and identified a combination regimen with temozolomide suitable for future clinical evaluation.

Abstract-We explored the effects of direct renal interstitial stimulation of dopamine D 1 -like receptors with fenoldopam, a selective D 1 -like receptor agonist, on renal sodium excretion and angiotensin type-2 (AT 2 ) receptor expression and cellular distribution in rats on a high-sodium intake. In contrast to vehicle-infused rats, sodium excretion increased in fenoldopam-infused rats during each of three 1-hour experimental periods (Ͻ0.001 Key Words: angiotensin Ⅲ dopamine Ⅲ receptors Ⅲ sodium excretion Ⅲ natriuresis Ⅲ receptor trafficking Ⅲ kidney T he kidney is endowed with 2 local hormonal systems that play a major role in the regulation of sodium (Na ϩ ) transport across the renal proximal tubule (RPT): the reninangiotensin system and the dopaminergic system. In vitro studies show that angiotensin II (Ang II), the major effector peptide of the renin-angiotensin system, acts at angiotensin type-1 (AT 1 ) receptors on RPT cell membranes to increase Na ϩ transport across the cell from the lumen into the interstitial space and peritubular capillaries by stimulating Na ϩ -hydrogen (H ϩ ) exchanger-3 (NHE-3) and Na ϩ ,K ϩ -ATPase activities, respectively. 1 On the other hand, dopamine (DA), synthesized in and secreted from RPT cells, activates D 1 -like receptors (D 1 and D 5 receptor subtypes) on RPT cells to inhibit Na ϩ reabsorption by inhibiting NHE-3 and Na ϩ ,K ϩ -ATPase activities. 2,3 Although these 2 hormonal systems act in opposite directions on RPT Na ϩ transport in vitro, little is known regarding the physiological interactions of intrarenal Ang II and DA in the control of Na ϩ excretion in vivo. Approximately 50% of basal Na ϩ excretion is mediated by the paracrine action of renal DA on RPT D 1 -like receptors. 4,5 However, the mechanisms of receptor interaction that govern DA-induced natriuresis are incompletely understood. DA downregulates AT 1 receptors (AT 1 Rs) in the RPT. 6 However, Ang II binds to angiotensin type-2 (AT 2 ) receptors (AT 2 Rs), as well as AT 1 Rs, and the effects of DA on AT 2 Rs are unknown.AT 2 Rs are expressed in the RPT but have a low degree of renal expression compared with that of AT 1 Rs. 7 The present study explores the direct renal interstitial (RI) stimulation of D 1 receptors with fenoldopam, a selective D 1 -like receptor agonist, and its effects on renal Na ϩ excretion and AT 2 R expression in the rat. We demonstrate that natriuresis induced by stimulation of renal D 1 -like receptors requires AT 2 R expression and recruitment to the RPT plasma membrane. In the presence of AT 2 R inhibition, D 1 -like receptor stimulation is not able to induce renal Na ϩ excretion.