We report the results of an expanded trial of 5-fluorouracil (5-FU) combined with high-dose folinic acid for treatment of patients with advanced colorectal or advanced gastric adenocarcinoma. In each treatment course, the patients received both 5-FU (340 to 400 mg/m2/d by intravenous (IV) infusion for a period of 15 minutes) and folinic acid (200 mg/m2/d by IV bolus) for 5 consecutive days, with a 21-day interval between courses. Eighty-six patients with colorectal carcinoma were evaluated. The combined complete and partial response rates were 39% for 54 patients who did not receive prior chemotherapy and 22% for 32 patients who had previously received chemotherapy. Four patients who were previously resistant to 5-FU attained objective responses. The median time to disease progression for the 28 responders was 10 months. The median survival time of responders was 19.5 months, and the probability of their being alive at 2 years was 40%. Of 27 patients with gastric adenocarcinoma, 13 (48%) responded to therapy. Their median time to disease progression was 5.5 months. The median survival time of responders was 11 months, and their probability of being alive at 15 months was 30%. Toxicity was within acceptable limits. Toxic effects included stomatitis, diarrhea, conjunctivitis, skin rash, and mild myeloid hypoplasia. In a separate study, plasma concentrations of L-folates greater than 10(-5) mol/L were achieved after a rapid single IV injection of 200 mg/m2 of folinic acid. Comparisons of our results with those reported in previous studies on 5-FU administered as a single agent suggest that, in advanced colorectal and gastric adenocarcinoma, folinic acid administered in high doses enhances the effectiveness of 5-FU administered concomitantly. Furthermore, some colorectal tumors that were previously resistant to 5-FU become sensitive to this drug. The survival of the patients who responded to therapy was markedly improved over that observed in reported series of untreated patients with advanced colorectal and gastric adenocarcinomas.

The main remethylation defects include disorders which all have defective methionine synthesis in common. Methylenetetrahydrofolate reductase deficiency impairs methyltetrahydrofolate synthesis, defects in cytosolic reduction of hydroxocobalamin (CblC/D) impair the synthesis of both methyl- and adenosyl cobalamin and deficiencies of methionine synthase (CblE/G) are associated with defective methyl cobalamin synthesis. The clinical presentation is characterized by acute neurological distress in early infancy. In childhood, patients present with progressive encephalopathy with an end-stage which has many signs in common with the adult onset form. In fact, both have more or less severe signs of subacute degeneration of the cord. Cobalamin defective patients must be treated with parenteral supplementation of hydroxocobalamin (1-2 mg per dose). Some methylenetetrahydrofolate patients could be folate responsive and must have a high-dosage folate trial. In addition, oral betaine supplementation (2-9 g per day depending on age) appears an effective means to prevent further neurological deterioration.

Altitude hypoxia induces an increase in erythropoiesis. Some of the factors involved in the control of altitude polycythemia were studied. Ten subjects (4 women, 6 men) were exposed for 3 wk to extreme altitude (6,542 m). Blood was withdrawn in normoxia (N) and after 1 wk (H1), 2 wk (H2), or 3 wk (H3) at 6,542 m for the measurement of serum erythropoietin (EPO), blood hemoglobin (Hb), hematocrit (Hct), intraerythrocyte folate (Fol), and plasma ferritin (Fer) concentrations. Renal blood flow (RBF) and absolute proximal reabsorption rate (APR) were measured by the p-aminohippuric acid and lithium clearance, respectively, in N and H2 conditions. O2 supply to the kidneys was calculated using RBF and arterial O2 content (CaO2). After an initial sharp increase in EPO, it decreased at H2 and H3. Hct and Hb increased from N to H1 and H2 and then unexpectedly decreased from H2 to H3. Mean corpuscular Hb content (MCHC = Hb/Hct) was lower in all H than in N conditions. Increase in EPO at H1 varied from 3- to 134-fold among individuals. Women showed a smaller increase in Hct and Hb and a greater decrease in MCHC. Two women showed a large increase in EPO without increase in Hb. Fol was not modified by altitude hypoxia. Fer showed a marked decrease in H1 and H3 compared with N. Hb was positively related to Fer in hypoxia. Iron intake in food was markedly decreased during the 2-wk ascent to 6,542 m. EPO was inversely related to CaO2 and positively related to APR.(ABSTRACT TRUNCATED AT 250 WORDS)

Three patients from a single family of six siblings had homocystinemia and homocystinuria due to 5,10-methylenetetrahydrofolate reductase deficiency and had severe recurrent strokes in adult life. Two of the patients died 1 year after clinical onset.

Although complementation studies have not been conducted, it is most likely these patients had cobalamin C disease. This study emphasizes the possibility of late-onset disease with purely neurological manifestations. Left untreated, this treatable condition can lead to death or irreversible damage to the nervous system. Screening for intracellular vitamin B12 dysmetabolism should, therefore, be considered in the investigation of adults with unexplained neurological disease, particularly when they are initially seen with a clinical picture suggestive of vitamin B12 deficiency.