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Biomedical subjects

C Hendrickson

Publications and source records attributed to C Hendrickson.

12 recordsLinked to original sources

Elective liver transplantation for the treatment of classical maple syrup urine disease.

An 8.5-year-old girl with classical maple syrup urine disease (MSUD) required liver transplantation for hypervitaminosis A and was effectively cured of MSUD over an 8-year clinical follow-up period. We developed a collaborative multidisciplinary effort to evaluate the effects of elective liver transplantation in 10 additional children (age range 1.9-20.5 years) with classical MSUD. Patients were transplanted with whole cadaveric livers under a protocol designed to optimize safe pre- and post-transplant management of MSUD. All patients are alive and well with normal allograft function after 106 months of follow-up in the index patient and a median follow-up period of 14 months (range 4-18 months) in the 10 remaining patients. Leucine, isoleucine and valine levels stabilized within 6 hours post-transplant and remained so on an unrestricted protein intake in all patients. Metabolic cure was documented as a sustained increase in weight-adjusted leucine tolerance, normalization of plasma concentration relationships among branched-chain and other essential and nonessential amino acids, and metabolic and clinical stability during protein loading and intercurrent illnesses. Costs and risks associated with surgery and immune suppression were similar to other pediatric liver transplant populations.

Adolescent↗

The KEN box regulates Clb2 proteolysis in G1 and at the metaphase-to-anaphase transition.

Clb2 mitotic cyclin inhibits cell cycle progression by preventing mitotic exit and DNA synthesis. To allow cell cycle progression, Clb2 proteolysis is triggered by Cdc20 during the metaphase-to-anaphase (M-A) transition and by Hct1 during mitotic exit and G1 [1-6]. A cis element called the destruction box is required for this proteolysis [7-11]. Recently, an additional cis element called the "KEN box" was also shown to be required for proteolysis of human CDC20 and Securin [3,12]. Using a novel color assay, we show that a Clb2 KEN box is required to target a fusion protein containing the first 124 amino acids of Clb2 for proteolysis. We further show that full-length Clb2 bearing mutations in the KEN box is degraded efficiently during the M-A transition, but poorly during G1. If the destruction box of Clb2 is mutated in combination with mutation of the KEN box, then this form of Clb2 is more stable than Clb2 bearing either mutation by itself during both M-A and G1. Our results show that the KEN box and the destruction box act together during both M-A and G1 to regulate Clb2 proteolysis.

Anaphase↗

Characteristics of flow-mediated brachial artery vasodilation in human subjects.

In an effort to determine whether arterial conductance vessels dilate in response to increased blood flow stimuli, brachial artery area (cm2) and diameter (cm) were derived by simultaneous measurement of forearm blood flow (ml/min.100 ml) and brachial artery blood flow velocity (cm/sec) following the release of arterial occlusion. Measurements were made at rest and at the time of maximal flow after the release of graded periods of forearm arterial occlusion (20 seconds to 10 minutes). These studies showed a graded large vessel dilation following occlusions of up to 1 minute (baseline diameter, 0.33 +/- 0.01; after 1 minute occlusion, 0.45 +/- 0.02 cm; p less than 0.05) after which time diameter plateaued (after 10 minutes of occlusion, 0.48 +/- 0.02 cm). In addition, the time course of diameter and flow changes after 3 minutes of arterial occlusion were examined. Flow was maximal at 5 seconds but diameter was maximal at 15-30 seconds after release. Furthermore, the half time for the return of diameter to baseline was longer than that for blood flow. We also measured the diameter after forearm heating (42 degrees C) and noted a substantial increase in diameter (before heating, 0.32 +/- 0.01; after heating, 0.39 +/- 0.02 cm; p less than 0.05). Finally, we applied pressure to the venous side of arteriovenous fistulae in five hemodialysis patients. This maneuver was associated with large reductions in forearm blood flow (baseline flow, 63.3 +/- 10.6; venous compression flow, 36.0 +/- 4.4 ml/min.100 ml; p less than 0.05) and a decrease in brachial artery size (baseline diameter, 0.63 +/- 0.07; venous compression diameter, 0.58 +/- 0.06 cm; p less than 0.05). We conclude that 1) the human brachial artery size changes in response to changes in blood flow, and 2) the maximal dilation occurs after maximal flow is noted. Although alternate explanations are possible for each of our observations, our results are most consistent with a flow-mediated, localized vasodilating process.

Adult↗

A Northern California Oncology Group randomized trial of leucovorin plus 5-fluorouracil versus sequential methotrexate, 5-fluorouracil, and leucovorin in patients with advanced colorectal cancer who failed treatment with 5-fluorouracil or 5-fluorodeoxyuridine alone.

The current study was initiated to confirm preliminary reports that 20% or more of patients with colorectal cancer who fail treatment with 5-fluorouracil (FUra) will respond to treatment with either leucovorin plus FUra or with sequential methotrexate, FUra, leucovorin. One hundred two patients with advanced, measureable colorectal cancer who failed treatment with FUra and/or 5-fluorodeoxyuridine (FUdR) were randomized to treatment with either high-dose leucovorin plus FUra (Arm B) or sequential methotrexate, FUra, leucovorin (Arm C). In this interim report, 92 patients were evaluable for toxicity and 89 patients were evaluable for response. Grade 3 or 4 nonhematologic toxicity which was primarily gastrointestinal was experienced by 25% of patients on both treatment arms during at least 1 treatment cycle. Hematologic toxicity was minimal. Among 43 evaluable patients on Arm B, there were 2 complete responses (5%) and 1 minor response (3%). Among 46 evaluable patients on Arm C, there was 1 complete response (2%), 1 partial response (2%), and 6 minor responses (14%). The median time to treatment failure was 2.2 months on Arm B and 3.5 months on Arm C. The median survival was 8.3 months on Arm B and 8.7 months on Arm C. Colorectal cancers that are resistant to FUra are cross-resistant to both experimental combinations.

Antineoplastic Combined Chemotherapy Protocols↗

A randomized phase III study of cisplatin with or without methotrexate for recurrent squamous cell carcinoma of the head and neck. A Northern California Oncology Group study.

Eighty patients with recurrent squamous cell cancer of the head and neck were randomized to cisplatin (80 mg/m2) every 3 weeks or cisplatin plus weekly methotrexate (250 mg/m2) with leucovorin. The overall response rate to cisplatin was 18%, with 10% complete responses. The overall response to the combination was 33% with 18% complete responses (P = 0.11). There was no difference in response duration, time to progression, or survival. There was no difference in renal toxicity between the 2 arms (creatinine greater than 2 mg/dl in 6% of the patients). There was significantly more leukopenia (64%), thrombocytopenia (18%), anemia (18%), and mucositis (33%) in the combination arm. This combination of two of the best agents for head and neck cancer did not improve response, but resulted in added toxicity.

Antineoplastic Combined Chemotherapy Protocols↗

Stabilization of human breast cancer progesterone (5020) receptor by sodium molybdate.

Inclusion of the salt, sodium molybdate, at 20 mmol/l concentration during the determination of progesterone receptor in human breast cancer cytosols was associated in a number of samples with marked stabilization of binding by the radioactive ligand, 5020, to 8S and 4S receptors. Both the percent of positive patients and the absolute amount of PR were increased, with the appearance of 8S peaks where none had been evident in controls without the salt, and increased amounts of 8S and 4S binding in other samples. In addition, results from some dextran-coated charcoal assays were altered, and positive samples incubated in the presence of the salt frequently yielded higher values of PR. Finally, estrogen receptor values determined by SDG assays have been increased in the presence of the salt. Routine addition of sodium molybdate to samples analyzed for PR by centrifugation overnight can be expected to yield an increased percent of receptor-positive patients with higher average concentration of receptor, compared with results of previous methodology. Its presence during the dextran-coated charcoal assay can also alter the measured binding. Although the stability of ER during overnight centrifugation is greater, in some patients additional receptor can be detected when buffers include this salt.

Breast Neoplasms↗

Sodium molybdate increases the amount of progesterone and estrogen receptor detected in certain human breast cancer cytosols.

When sodium molybdate is added at a final concentration of 20 mM, additional 8S and 4S progesterone (3H-R5020) receptor can be detected in the cytosols from a number of human breast cancers. Additional estrogen receptor also could be measured in some cytosols, and a quantitative temperature-dependent conversion of 8S to 4S binding molecules achieved. Sodium molybdate also prevented the loss of binding activity that occurred when cytosols were incubated at 30 degrees in the absence of added estradiol. In addition to increasing the amount of progesterone receptor, and to a lesser extent estrogen receptor that may be detected, elicidation of the mechanism by which this salt stabilized receptors should contribute to further understanding of how cytosol steroid receptor content and function is regulated.

Breast Neoplasms↗

A reversed PRE.

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Animals↗