Pyridoxylated adult human hemoglobin (HbAo) was prepared using a one molar equivalent of pyridoxal 5-phosphate (PLP) per heme and reduced with either NaCNBH3 or NaBH4. A separate sample was pyridoxylated and passed through a mixed-bed ion exchange column without reduction. All three preparations had a P50 of 29 +/- 2 torr and a cooperativity of n = 2.4 +/- 0.1. These preparations, in both the oxy and deoxy forms, were then treated with 7 equivalents of glutaraldehyde per tetramer at pH 6.8 at 4 degrees C and at room temperature. The polymerization invariably reduced the P50 to 18 +/- 2 torr with Hill coefficients of less than 2. These solutions, with or without further reduction using NaCNBH3, all retained the PLP in differing amounts (2-3 moles/tetramer). Methemoglobin concentrations were increased during the polymerization reaction. The normal pyridoxylation procedure, using sodium borohydride reduction, resulted in a number of different molecular species. Polymerization with glutaraldehyde caused a further proliferation of molecular species that could not be separated by anion exchange chromatography or by isoelectric focusing. The extent of polymerization, estimated by gel exclusion chromatography and SDS polyacrylamide gel electrophoresis, was from 40 to 50%. Analysis of the reverse phase chromatograms, which separate the heme and the alpha- and beta-chains, showed extensive polymerization and distribution of the radioactively labeled PLP on the protein for all preparations. All of the polymerized and pyridoxylated samples were unstable, and showed different chromatographic patterns after storage at 4 degrees C for 1 month. Attempts to stabilize these preparations by further reduction with NaCNBH3 gave products with a lower P50 and lower cooperativity. When the reactions were conducted with a purified HbAo, heterogeneity was somewhat decreased compared to the normally used stroma-free hemoglobin, but a large number of molecular species were still formed.

Aldehydes↗

PubMedDate not supplied

Herbal therapies in rheumatology: the persistence of ancient medical practices.

OBJECTIVE: To determine how frequently herbal remedies are employed as alternative therapies in rheumatic diseases, and the historical justification for their use. METHODS: We conducted a survey in 250 outpatients in the rheumatology clinic of a teaching hospital in México. We registered general demographic information and the previous use of herbal remedies for rheumatic conditions, how effective they were, and the presence of adverse effects during their use. We identified the herbs employed, and cross-checked them with medical texts from the 16th through the 18th centuries on the use of herbal remedies. RESULTS: Of 250 surveyed patients, 126 (51%) had used herbal remedies for their rheumatic conditions. 63% of all users reported them to be effective for the purpose they had been prescribed. 12% reported adverse effects, none of them life-threatening. Being a user had no relation with the patients' formal education. Three patients did not answer the survey. We were able to identify 67 plants. One third of these are either prescribed for rheumatic conditions in the consulted bibliography, or else were used for the same purpose by ancient Mexican cultures. CONCLUSION: Herbal remedies are frequently used for rheumatic conditions. Some of them have an historical antecedent for their use in rheumatic conditions. They deserve a cautious evaluation as adjunctive therapies in rheumatic diseases.

Culture↗

PubMedDate not supplied

Recombinant human erythropoietin does not increase clotting in vascular accesses.

The incidence of vascular access clotting was evaluated over 5.25 years. The first 32 months served as a control period. During the second period of 31 months, recombinant human erythropoietin (epoetin) was used for an average duration of 13 months (range, 2-32 months) in 79 patients. The overall incidence of vascular access clotting decreased from a monthly rate of 0.06 to 0.03 events per patient-month over the 5 year period. Distribution of the number of events per patient did not differ between the two periods, with 55% to 60% of patients having no clotting episode. Patients with recurrent clotting (two or more events) accounted for 68% of episodes. During the second period, there were no differences in the incidence of vascular access clotting in epoetin treated patients vs untreated patients (0.38 events per patient-year vs. 0.46 events per patient-year, both slightly lower than in period 1 [0.52 events per patient-year]). It is concluded that epoetin does not increase vascular access clotting.

Anemia↗

PubMedDate not supplied