Hereditary leiomyomatosis and renal cell cancer (HLRCC) is an autosomal dominant disorder characterized by smooth-muscle tumors of the skin and uterus and/or renal cancer. Although the identification of germline mutations in the fumarate hydratase (FH) gene in European families supports it as the susceptibility gene for HLRCC, its role in families in North America has not been studied. We screened for germline mutations in FH in 35 families with cutaneous leiomyomas. Sequence analysis revealed mutations in FH in 31 families (89%). Twenty different mutations in FH were identified, of which 18 were novel. Of these 20 mutations, 2 were insertions, 5 were small deletions that caused frameshifts leading to premature truncation of the protein, and 13 were missense mutations. Eleven unrelated families shared a common mutation: R190H. Eighty-one individuals (47 women and 34 men) had cutaneous leiomyomas. Ninety-eight percent (46/47) of women with cutaneous leiomyomas also had uterine leiomyomas. Eighty-nine percent (41/46) of women with cutaneous and uterine leiomyomas had a total hysterectomy, 44% at age < or =30 years. We identified 13 individuals in 5 families with unilateral and solitary renal tumors. Seven individuals from four families had papillary type II renal cell carcinoma, and another individual from one of these families had collecting duct carcinoma of the kidney. The present study shows that mutations in FH are associated with HLRCC in North America. HLRCC is associated with clinically significant uterine fibroids and aggressive renal tumors. The present study also expands the histologic spectrum of renal tumors and FH mutations associated with HLRCC.

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We have measured, directly and simultaneously, changes in extracellular volume and intra- and extracellular pH during ischemia in the isolated rat heart using 31P NMR spectroscopy. Hearts were perfused with buffer containing 15 mM sodium phenylphosphonate at pH 7.4. Wash in and wash out experiments showed that phenylphosphonate entered only the extracellular (interstitial, vascular and chamber) space of the heart and had no adverse effects on myocardial energetics, contractile function or coronary flow rate. Hearts were subjected to 28 min of total, global ischemia, during which the phenylphosphonate resonance area in the 31P NMR spectra decreased by 83%, indicating that extracellular fluid had moved rapidly from the heart to the bath surrounding the heart, partly as a result of vascular collapse. A separate, morphological study confirmed that 95% of the vasculature had collapsed by 28 min ischemia. Intra- and extracellular pH were determined from the chemical shifts of the P(i) and the phenylphosphonate resonances, respectively. In the pre-ischemic rat heart, intracellular pH was 7.15 +/- 0.03 and extracellular pH was 7.39 +/- 0.03. By 4 min of ischemia, intra- and extracellular pH were the same and decreased concomitantly throughout the remainder of ischemia to final values of 6.09 +/- 0.19 and 6.16 +/- 0.23, respectively. On reperfusion, the extracellular volume and pH returned to pre-ischemic levels within 1 min, but restoration of intracellular pH took > 2.5 min. Thus, a large volume of extracellular fluid moves out of the rat heart to the surrounding bath and the intra- and extracellular pH become the same during total, global ischemia.