1,25-Dihydroxyvitamin D resistance, rickets, and alopecia

Two unrelated kindreds with four affected children having 1,25-dihydroxyvitamin D resistance, rickets, and alopecia are described. The children exhibited early onset of severe rickets with hypocalcemia, hypophosphatemia, elevated serum alkaline phosphatase levels, and secondary hyperparathyroidism. Radiography showed diffuse demineralization and classic changes of rickets. All affected children had total-body alopecia. Serum levels of 1,25-dihydroxyvitamin D3 were elevated and rose to extremely high values during treatment, with no apparent change in the mineral disorder. However, secondary hyperparathyroidism and hypophosphatemia did remit during treatment despite persistently low calcium levels. Skin biopsy was performed in the parents and affected children in one kindred. Analysis of 1,25-dihydroxyvitamin D3 receptors in cultured fibroblasts indicated apparent normal receptors in the parents and undetectable receptors in both affected children. After long periods of treatment with vitamin D metabolites and mineral replacement, healing took place in the older child in each kindred. These data suggest that the healing occurred spontaneously as the children reached seven to nine years of age rather than as a result of the treatment. The biochemical lesion in these children appeared to be a genetically transmitted defect in the 1,25-dihydroxyvitamin D3 receptor. The mechanisms by which healing was initiated and maintained remain to be elucidated.

Characterization of insulin-like growth factor I receptors on cultured rat bone cells: regulation of receptor concentration by glucocorticoids

A specific receptor for insulin-like growth factor I (IGF-I) has been demonstrated in cultured fetal rat osteoblast-like bone cells. Specific binding of [125I]IGF-I to bone cells incubated at 15 C reached a steady state by 5 h. Half-maximal inhibition of [125I]IGF-I binding by unlabeled IGF-I was observed at 7 ng/ml. Multiplication-stimulating activity, insulin, and proinsulin were less effective than unlabeled IGF-I in competing for receptor occupancy. Scatchard analysis showed a curvilinear plot, with a Ka similar to that observed in human fibroblasts. Incubation of cell monolayers with glucocorticoids resulted in a concentration-dependent increase in [125I]IGF-I binding. This increase in [125I]IGF-I binding was dependent on cell density. After a 2-day exposure to dexamethasone, no increase in binding was observed in sparsely plated cells; however, an increase in binding was observed after 3 days in culture (log phase) and was maximal by 5 days (peak log phase). These data indicate that rat bone cells possess a specific receptor for IGF-I with binding characteristics similar to those reported in human fibroblasts, and that IGF-I receptor concentrations are increased by exposure to glucocorticoids. A role for glucocorticoids and IGF-I in rat bone proliferation is suggested by these findings.

Diminished biparietal diameter and abdominal circumference growth in twins

Forty-three women with uncomplicated twin pregnancies and reliable menstrual dates had serial ultrasonic measurements of the fetal biparietal diameter (BPD) and abdominal circumference. The 25th, 50th, and 75th fetal BPD and abdominal circumference growth percentiles were generated from this normal twin population and compared with those for singletons. A slowing of both BPD and abdominal circumference growth in twins was noted in the third trimester. However, newborn anthropometric data were collected that suggest that the head circumference of twins is comparable to that of singletons. This discrepancy between ultrasonic BPD and neonatal head circumference in predicting head size may possibly be explained by dolichocephaly attributed to uterine crowding. For the antenatal assessment of growth in twins the authors recommend the use of BPD and abdominal circumference charts derived specifically from such uncomplicated twin pregnancies. When the BPD growth is abnormal, the head circumference and abdominal circumference should be measured to assess whether or not fetal growth is normal.

Tryptic digestion of rabbit skeletal myofibrils: an enzymatic probe of myosin cross-bridges

Tryptic digestion of rabbit skeletal myofibrils under physiological ionic strength and pH conditions was used as a probe of cross-bridge interaction with actin in the presence of nucleotides and pyrophosphate. Under rigor conditions, digestion of myofibrils at 24 degrees C results in the formation of 25K, 110K [heavy meromyosin (HMM)], and light meromyosin (LMM) fragments as the main reaction products. Very little if any 50K peptide is generated in such digestions. In the presence of magnesium pyrophosphate, magnesium 5'-adenylyl imidodiphosphate (MgAMPPNP), and MgATP, the main cleavage proceeds at two positions, 25K and 75K from the N-terminal portion of myosin, yielding the 25K, 50K, and 150K species. The relative amounts of the 50K, 110K, and 150K peptides and the rates of myosin heavy-chain digestion in the presence of pyrophosphate and AMPPNP indicate partial dissociation of myosin from actin. Direct centrifugation measurements of the binding of HMM and subfragment 1 (S-1) to actin in myofibrils confirm that cross-bridges partition between attached and detached states in the presence of these ligands. In the presence of MgADP, HMM and S-1 remain attached to actin at 24 degrees C. However, tryptic digestion of myofibrils containing MgADP is consistent with the existence of a mixed population of attached and detached cross-bridges, suggesting that only one head on each myosin molecule is attached to actin. As shown by tryptic digestion of myofibrils and the measurements of HMM and S-1 binding to actin, nucleotide- and pyrophosphate-induced dissociation of cross-bridges is more pronounced at 4 than at 24 degrees C.(ABSTRACT TRUNCATED AT 250 WORDS)

Social status, gonadal state, and the adrenal stress response in the lizard, Anolis carolinensis

Adult males of the small arboreal iguanid lizard, Anolis carolinensis, form social dominance hierarchies when placed in habitats with limited resources. Skin color changes occur during hierarchy formation, most conspicuously in subordinates, who appear darker (more brown) than dominants (more green). Because skin color in this species is under the control of hormones frequently associated with physiological stress, radioimmunoassay of plasma levels of the principal reptilian adrenal steroid, corticosterone, was performed. To examine the influence of gonadal androgen, known to influence the aggression that attends hierarchy formation, lizard pairs were constituted in which one or both members were castrated. Corticosterone levels of intact subordinates were significantly elevated, whereas those of castrated subordinates or dominants showed levels comparable to those of isolates. No significant differences in spermatogenic stage could be detected between intact dominants or subordinates.

Effects of intensive induction chemotherapy for extensive-disease small cell bronchogenic carcinoma in protected environment-prophylactic antibiotic units

Fifty-five patients with extensive-disease small cell bronchogenic carcinoma received three courses of intensive, inpatient, remission induction chemotherapy in (25 patients) or out (30 patients) of protected environment-prophylactic antibiotic (PEPA) units. Chemotherapy consisted of ECHO induction (E = epipodophyllotoxin VP-16-213; C = cyclophosphamide; H = hydroxydaunorubicin; O = Oncovin) and PRIME maintenance (PR = procarbazine; I = ifosfamide; ME = methotrexate). All evaluable patients (22 in the protected environment group and 26 in the control group) had a complete (50 percent in the protected environment group and 54 percent in the control group) or partial (50 percent in the protected environment group and 46 percent in the control group) remission. Median response and survival durations for both treatment groups were similar. The median survival duration of patients with a complete remission favored the protected environment group (16.5 versus 12.67 months; p = 0.20). Two patients (one from each group) are alive and disease-free for more than four years. Myelosuppression was intense and more pronounced in the protected environment group (p less than or equal to 0.01). Infectious complications were less common in patients receiving intravenous prophylactic antibiotics and in those treated with intravenous antibiotics in PEPA units (p less than or equal to 0.04). There were no treatment-related deaths, although treatment might have contributed to the death of three patients in the protected environment group and four in the control group. The administration of intensive ECHO induction chemotherapy to patients with extensive small cell bronchogenic carcinoma produced a high complete remission rate, although there was no significant long-term survival advantage over a program of less intensity. The administration of intravenous prophylactic antibiotics and the use of PEPA units significantly reduced the infectious morbidity of chemotherapy.

Small cell bronchogenic carcinoma: factors associated with pneumonia during chemotherapy

Sixty-five patients with small cell bronchogenic carcinoma were treated with intensive induction chemotherapy and supportive treatment. The clinical course of 43 patients who had pretreatment spirometry and arterial blood gases was studied. Thirteen patients developed pneumonia. Moderate hypoxemia, advanced age, and a low forced expiratory flow 25%-75% were associated with the development of pneumonia. Endobronchial obstruction and neutropenia, other factors associated with infection in cancer patients, appeared to be less important in this patient population.

Synthesis of, and animal experiments with, N-isopropyl-p-123I-iodo-amphetamine (IMP) and 18F-3-deoxy-3-fluoro-D-glucose (3-FDG) as tracers in brain and heart diagnostic studies

For the investigation of brain functions 18F-3-deoxy-3-fluoro-D-glucose (3-FDG) and N-isopropyl-p-123I-iodo-amphetamine (IMP) were synthesized and the course of radioactivity measured in several organs of mice. The results can be summarized as follows: IMP is rapidly extracted from the blood and reaches a value of less than 1% g within the first 15 min; 123I-radioactivity in the lungs shows a maximum of 76%/g as soon as half a minute after injection and decreases with a concomitant increase in the liver and brain; The maximum 123I-uptake in the brain of 11%/g is reached after 30 min and levels off at a constant value of 10%/g; 30 min after injection the brain/blood ratio for IMP is about 14; The time course of 3-FDG in the brain has a maximum of 4.8%/g as soon as 5 min after injection and decreases to a constant value of 3%/g within 1 hr; and Accumulation of 18F- radioactivity in the heart reaches a maximum of 14%/g after 1 hr and is eliminated with a half-life of 300 min. Comparative clinical studies with 3-FDG and 3-0-11C-methyl-D-glucose (CMG) have shown that 3-FDG can be considered as a CMG-analogue and thus can be used for the in-vivo determination of local glucose perfusion and transport rates.

Impact of the timing of triple intrathecal therapy on remission induction in childhood acute lymphoblastic leukemia: a Pediatric Oncology Group study

Five weekly doses of triple intrathecal (IT) chemotherapy (methotrexate, hydrocortisone, cytosine arabinoside) starting on day 1 of treatment were added to systemic induction therapy in a regimen (Arm 3) that was compared to three other regimens (Arms 1, 2, and 4) in which central nervous system (CNS) prophylaxis was initiated after complete marrow remission (CR) was attained. The CR rate for Arm 3 was only 83% as compared to 91-92% for other Arms. The lower CR rate was the result of a significantly higher death rate during induction for patients receiving early CNS prophylaxis (10.6 vs 0.9-3.5%). These differences were only observed in high risk patients as defined in the study. The early death rate was especially high (30%) in Arm 3 for children who were less than 2 years of age. Infection was the primary cause of morbidity and mortality. Severe infection following the initiation of induction therapy was found in 16.7% of patients on Arm 3 vs 1.8-6% on other regimens. Immediate triple IT chemoprophylaxis during induction therapy of acute lymphoblastic leukemia as used in this study appears to be associated with increased susceptibility to infection and this form of CNS prophylaxis has increased hazards of morbidity and mortality in infants and other high risk patients.

Vitamin content of some normal human brain segments

Nicotinates, pantothenates, riboflavin, vitamins B6 and B12' free (acetyl) and total (free and bound) choline, biopterin, thiamin, biotin, methylated and nonmethylated folates in frontal, temporal, precentral, postcentral, and occipital cortex, thalamus, cerebellum, pons, basal ganglia, and substantia nigra were estimated. Nicotinates are significantly more concentrated in basal ganglia and thalamus than pons. Nonmethylated folate content is not significantly varied in brain segments; the pons contains more methylated folate. Riboflavin content is higher in the basal ganglia and temporal cortex than frontal cortex. Biotin is concentrated in pons and basal ganglia. Thiamin concentration is less in the postcentral cortex than the thalamus and substantia nigra. Biopterin is significantly higher in substantia nigra and basal ganglia than the other brain segments. Total choline content is high in substantia nigra, pons, and thalamus; free (acetyl) choline is significantly elevated in basal ganglia. B12 content is less concentrated in the cortex segments. B6 is highly concentrated in the basal ganglia. Pantothenate content is elevated in pons when compared to the various cortex segments and cerebellum.

Vitamin D resistant rickets with alopecia: cultured skin fibroblasts exhibit defective cytoplasmic receptors and unresponsiveness to 1,25(OH)2D3

A new case of vitamin D dependent rickets (Type II) with alopecia in a 5 yr old child is reported. Skin fibroblasts were propagated in culture and analyzed for cytoplasmic 1,25(OH)2D3 receptors. The rachitic cells failed to exhibit specific, high-affinity binding sites by either Scatchard analysis or sucrose density gradient. Furthermore, a rise in 24-hydroxylase activity could not be elicited following incubation of the rachitig cells with 1,25(OH)2D3. Fibroblasts from a non-rachitic child examined in parallel experiments demonstrated high affinity binding sites (Kd = 0.1 nM, Nmax = 33 fmol/100 micrograms DNA) and the induction of 24-hydroxylase activity. The molecular basis of the unresponsiveness of the cells from the rachitic child appears to be due to defective or absent 1,25(OH)2D3 receptors.

Influence of chest radiotherapy in frequency and patterns of chest relapse in disseminated small cell lung carcinoma. A Southwest Oncology Group Study

The value of radiotherapy to the chest (RC) in disseminated small cell lung carcinoma (SCLC) has been questioned. Two protocols for disseminated SCLC from the Southwest Oncology Group (SWOG) have been compared. They were developed four years apart. The first one included radiotherapy (RT), 3000 rad in two weeks, to the primary tumor, mediastinum and supraclavicular areas, while the second one deleted any RC. Multidrug chemotherapy (CT) and brain RT were used in both protocols. Nonresponders to CT were removed from the study. Our main findings are as follows: (1) Initial chest relapses (patients with no initial extrathoracic relapse) have increased from 24-55% when RC is not given (P = 0.0001). Overall chest relapse (adding those patients that relapsed simultaneously in the chest plus other sites) in the second protocol was 73%. (2) Amount of response to CT does not influence the chances for relapse. Even complete responders to CT have a high chance for chest relapse. (3) Sites of relapse without RC are mainly in the primary tumor, ipsilateral hilus and mediastinum. (4) With RC, relapses shift to the chest periphery, mostly to the lung outside the radiotherapy field and to the pleura. (5) The two very different CT regimens have produced similar percentages and duration of response. (6) CT schema with periodic reinductions prolongs duration of response and survival over schema with continuous maintenance. Hence, interruption of CT to allow RC does not seem to adversely influence CT efficacy. From our results and the review of the literature we conclude that: (1) patients with disseminated SCLC that respond to CT should be given RC to decrease chest relapses. (2) A dose of 3000 rad in two weeks seems to be enough to produce a low percentage of chest relapse in disseminated SCLC, as survival of these patients is short and many will die prior to developing chest relapse. However, according to the literature, 4000-4800 rad is probably a more effective dose. (3) More studies and guidelines are needed to outline proper boundaries of radiotherapy fields, to decrease chances of peripheral chest relapses. (4) Median survival might not be a good parameter to evaluate the impact of RC in disseminated SCLC. The study of long-term survivors seems to be more important.

Equivalence of intrathecal chemotherapy and radiotherapy as central nervous system prophylaxis in children with acute lymphatic leukemia: a pediatric oncology group study

The efficacy of intrathecal (i.t.) chemoprophylaxis was compared with cranial radiotherapy plus i.t. methotrexate (MTX) in a Southwest Oncology Group (SWOG) study accessing 408 patients from September 10, 1974, to October 29, 1976. Randomization was stratified by prognostic groups (PGs) based on age and white blood cell count at diagnosis. All received induction therapy with vincristine and prednisone (Pred); maintenance therapy consisted of daily 6-mercaptopurine and weekly MTX. Consolidation for arm 1 employed cyclophosphamide and L-asparaginase followed by biweekly 5-day courses of parenteral MTX. The first dose of each course of MTX was given i.t. in triple chemoprophylaxis (MTX, hydrocortisone, and cytosine arabinoside). During maintenance, i.t. chemoprophylaxis was bimonthly and 28-day Pred "pulses" were given every 3 mo. Arm 2 i.t. chemoprophylaxis was initiated on achievement of remission, and arm 3 i.t. on treatment day 1; both continued 1 yr. Arm 4 induction included two doses of L-asparaginase. On achievement of remission, CNS prophylaxis (radiotherapy, 2400 rad plus i.t. MTX) was given. For all, therapy was discontinued after 3 yr of continuous complete remission. Survival and the incidence of extramedullary relapse were similar for the treatments employing either i.t. chemoprophylaxis or radiotherapy plus i.t. MTX upon achievement of remission. Among poor prognosis patients, the duration of complete remission was significantly better with the regimen using i.t. chemoprophylaxis as a component of consolidation therapy than with the regimen employing i.t. chemoprophylaxis early in induction or with the treatment using radiotherapy plus i.t. MTX for CNS prophylaxis. In poor prognosis patients, the initiation of i.t. chemoprophylaxis during consolidation was also associated with hematologic remissions that were significantly better than those achieved with the treatment employing early CNS chemoprophylaxis or with the regimen using radiotherapy plus i.t. MTX. Among average prognosis patients, therapy with CNS chemoprophylaxis during consolidation, as well as the regimen employing radiotherapy and i.t. MTX for CNS prophylaxis, produced hematologic remissions that were significantly longer than those obtained with the regimen using early CNS chemoprophylaxis. Hematologic remissions of good prognosis patients who received treatment with the regimen employing i.t. chemoprophylaxis during consolidation were statistically superior when compared to the regimen employing CNS radiotherapy plus i.t. MTX. This study indicates that i.t. chemoprophylaxis may be substituted for cranial radiotherapy when utilizing effective systemic regimens. Additionally, chemoprophylaxis may be reduced from 3 to 1 yr in patients with good prognostic factors.

The influence of radiation therapy quality control on survival, response and sites of relapse in oat cell carcinoma of the lung: preliminary report of a Southwest Oncology Group study

Two hundred and ninety-eight patients with limited (confined to chest and supraclavicular area, encompassable by a single radiation portal) small cell carcinoma of the lung were entered on Southwest Oncology Group Protocol 7628. Patients were treated with multi-agent chemotherapy and radiation therapy with or without BCG. Radiation therapy quality control analysis, including dosimetric reconstruction and port film review was introduced after the protocol was activated and was retrospectively applied. Patients who were considered major protocol variations had statistically worse survival (40 weeks versus 60 weeks; P = .002), a lesser improvement in response rate after induction chemotherapy (27 versus 48%; P = .05) and a higher chest failure rate (77 versus 55%; P = .047) than evaluable patients. Five patients relapsed in the brain, all associated with chest failure. Quality control is essential in cooperative group studies.

Anesthesia for tracheal stenosis, tracheoesophageal fistula and status asthmaticus

A 26-year-old female patient who, in addition to tracheal stenosis, also suffered from status asthmaticus and an esophagotracheal fistula, underwent surgery for resection of the stenosed segment, reconstruction of tracheal continuity and fistula repair. The therapy for her asthma and the anesthetic management for bronchoscopy and, later, definitive surgery are described. Radiological photographs (before and after surgery) as well as results of respiratory function tests are shown.

Correction of perfusate concentration for sample removal

Repeated sampling of a drug solution that is recirculated through a perfused body increases the rate of drug disappearance from the perfusate. When the volume of the drug solution (VT) is maintained constant by addition of drug-free perfusate after sampling, the measured drug concentration (Ci) can be corrected for drug removed in previous samples by using the equation C'i = CiVTC'i-1/(VT - VS)Ci-1, where C'i is the corrected drug concentration in the ith sample, VS is the volume of the sample, and C'1 = C1. An error in an particular Ci is not transmitted to a subsequent C'i value. The method can be used when the time interval between samples and when VS vary from sample to sample, but return of the drug from the perfused body to the perfusate after sampling may cause C'i to be overestimated.

Stable isotope analysis by fast-atom bombardment labeling of UDP-glucuronic acid

Fast-atom bombardment mass spectrometry is found to provide a method for analysis of isotopes in the enzyme cofactor uridine-5'-diphosphoglucuronic acid, heretofore unsusceptible to mass-spectral characterization. This technique was used to determine optimal conditions for the introduction of 18O by acid-catalyzed exchange in H218O and to evaluate the loss of the isotope when labeled cofactor is used in enzymatic incubations. Fast-atom bombardment mass spectrometry provided a quantitative assessment of various isotopic species and also permitted the location of the isotopes in the molecule to be determined.

Combination chemotherapy, radiotherapy, and BCG immunotherapy in limited small-cell carcinoma of the lung: a Southwest Oncology Group Study

From November 1976 to March 1979 the Southwest Oncology Group treated 298 patients with limited (disease confined to the chest and encompassed by one radiotherapy port) small-cell carcinoma of the lung with combination chemotherapy and radiotherapy with or without BCG immunotherapy. Two induction chemotherapy programs were utilized: (1) cyclophosphamide, vincristine, methotrexate, fluorouracil; or (2) cyclophosphamide, doxorubicin, and vincristine. Patients received 4500 rads of radiation therapy to the bulk primary tumor and 3000 rads to whole brain followed by maintenance chemotherapy. One-half of all the patients were randomized to receive one vial (5 x 10(8)) of high viability Pasteur BCG by scarification technique given on days 8 and 15 of each 21--28 day treatment cycle. Increased granulocytopenia accompanied the addition of BCG immunotherapy. Patients receiving BCG achieved a response rate of 49% vs. those patients not receiving BCG of 44% (P = 0.579). Median response duration was 40 weeks for the BCG arms and 38 weeks for the arms without BCG; survival was no different, 42 weeks for the BCG arms vs. 50 weeks for the arms without BCG. In patients who responded to therapy and survived longer than one year, those who continued to receive BCG therapy demonstrated a slight, yet significant, survival benefit over those patients not receiving BCG (93 weeks vs. 81 weeks, P = 0.03). It appears that BCG immunotherapy has no beneficial effect on response rate, duration of response, or survival in programs using chemotherapy and radiotherapy for control of limited small-cell carcinoma of the lung except in this small group of long-term survivors.

Limited squamous cell carcinoma of the lung: a Southwest Oncology Group randomized study of radiation with or without doxorubicin chemotherapy and with or without levamisole immunotherapy

In 1976, the Southwest Oncology Group activated a four-arm randomized study of limited squamous cell carcinoma of the lung. The purpose of this study was to determine if doxorubicin and/or levamisole added to radiation therapy improved the local control rate and survival in patients with limited squamous cell carcinoma of the lung. Of the 107 eligible patients, 15 (14%) had complete responses and 20 (19%) had partial responses. When compared by chemotherapy, immunotherapy, and performance status, no statistically significant difference was found in response rates or in survival. Although not statistically significant, the survival and response rates of patients in the combined levamisole arms were shorter than those of patients in the combined arms not containing levamisole. Patients receiving radiation therapy alone had the best survival. The irradiated field was the site of failure in 68 (88%) of the 77 patients in whom the site of failure was specified. Fifty (65%) of the patients failed in the radiation therapy field only. Chemotherapy and/or immunotherapy as employed in this protocol were of no benefit.

Intergroup Hodgkin's disease in children study of stages I and II: a preliminary report

The intergroup study of involved-field (IF) radiotherapy, IF radiotherapy plus MOPP chemotherapy, and extended-field (EF) radiotherapy for treatment of Hodgkin's disease in children has assessed 305 patients. Of these, 279 were "not ineligible" (no mediate cause for disqualification). Among 223 randomized patients, 144 were evaluable, 131 had documentation of complete or partial remission, 20 of the remitters relapsed, and two died. Among 62 nonrandomized patients with favorable presentations (unilateral upper neck, unilateral inguinal, or massive mediastinal disease), 29 had documented remission, two relapsed, and none died. Length of initial disease control (LIDC) was used to measure duration of response. LIDC was best in patients given IF plus MOPP, and 95% are disease free. EF was better than IF radiotherapy (P = 0.004). Of the disease characteristics prognostic for response (stage, histologic subtype, and presence of symptoms), only the last factor had a statistically significant effect on LIDC (P = 0.004). Ninety-six percent of the patients survive. Using criteria developed by the committee, 23% of the staging procedures reviewed were nonevaluable and 28% of the radiotherapy treatments were nonevaluable. The necessity for criteria for evaluation of staging and treatment is certain. Length of followup is too short for correlations of treatment with significant late effects and for relevant therapeutic recommendations.

Phase II study of anguidine in gastrointestinal malignancies: a Southwest Oncology Group study

The Southwest Oncology Group conducted a phase II study of anguidine in 134 patients with gastrointestinal malignancies. Anguidine was administered as a 4-hour infusion at doses of 3.0 and 4.5 mg/m2 daily x 5. Response rates for patients with colon carcinoma were 22% (four of 18 patients without previous chemotherapy) and 6% (four of 63 patients with previous chemotherapy). There were no responses in patients with pancreatic cancer (four patients) or gastric cancer (six). Toxic effects included thrombocytopenia (19.8%), leukopenia (18.8%), nausea and vomiting (49%), hypotension (37%), and confusion (12%). Antitumor activity of anguidine in patients with colon cancer may be similar to that of 5-FU, but nonhematologic toxicity is substantial.