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Biomedical subjects

A Tejeda

Publications and source records attributed to A Tejeda.

5 recordsLinked to original sources

Modeling column regeneration effects on ion-exchange chromatography.

The effect of in-place regeneration on equilibrium and kinetic characteristics of the adsorption of bovine serum albumin to a DEAE-cellulose anion exchanger has been determined. Regeneration with sodium hydroxide and time of exposure showed no effect on equilibrium behavior. Breakthrough curves were measured for protein adsorption on fixed-bed columns and analyzed by a simple model to determine the relevant rate constants for the adsorption process. It was found that forward adsorption rate constant decreased exponentially with the chemical treatment exposure time. The implications of the results on the design and optimization of ion-exchange chromatographic processes are discussed.

Adsorption↗

Hypophosphatemia in end stage renal disease.

A case of hypophosphatemia in a 55-year-old black female on maintenance hemodialysis is described. She developed multiple bone fractures and congestive heart failure during her 10-year period on hemodialysis. Iliac crest bone biopsy revealed osteomalacia with absent aluminium stores. Management was difficult due to her noncompliance secondary to severe depression. Though osteomalacia and cardiomyopathy due to hypophosphatemia are described in patients with end stage renal disease on dialysis, it is an uncommon entity.

Bone and Bones↗

[Articular and extraarticular involvement in inflammatory bowel diseases].

Idiopathic inflammatory bowel disease include basically two disorders: ulcerative colitis and Crohn's disease. Both diseases are chronic and of unknown etiology and extraintestinal manifestations are seen in a high number of these patients. We studied 18 patients (7 female, 11 male) with previous diagnosis of inflammatory bowel disease (14 ulcerative colitis, 2 Crohn's disease, 1 pancolitis, 1 ulcerative proctitis) in order to search for extraintestinal manifestations with emphasis on osteoarticular and ocular involvement. The mean age at the time of diagnosis of the inflammatory bowel disease was 44 years (range 20 to 71 years). Mean time duration of the inflammatory bowel disease was 7 years (range 1 to 24 years) and of the articular manifestations 3.2 years (range 1 to 8 years). The osteoarticular manifestations developed after the diagnosis of the bowel disease in all but one patient (simultaneously) 17/18 patients had artralgias, 7/18 lumbalgia, 3/18 talalgia, 1/18 knee arthritis. (table I) Only six of the 17 patients with orteoarticular involvement has simultaneous activity of the underlying bowel disease. All the 18 patients were taking 2 g/day of sulfasalazine. Radiographic screening in all patients revealed sacroiliitis in 10. (table II) Of the 10 radiographic sacroiliitis 4 were grade I (confirmed by technetium phosphate scans, 2 were grade II and 4 grade III-IV. Three of the ten patients with radiographic sacroiliitis were asymptomatic (table II). Axial computed tomography was performed done in two patients: a) in one case to exclude osteitis condensens ilii, and b) in the other case to exclude septic arthritis. The severity of the sacroiliac damage was related with a longer duration of the inflammatory bowel disease.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

Complex segregation analysis of diabetes mellitus.

Complex segregation analysis was applied to a sample of 12,293 nuclear families each with at least 1 diabetic patient. The families were divided into two groups depending on the proband's treatment: insulin-dependent (IDG) and insulin-independent (IIG). Heterogeneity analysis has revealed a highly significant difference in the IIG group when families were divided into different mating types. The higher recurrence risk was found in the group with affected mothers. Also evidence for a major recessive gene was found in the IGG group, while it was not possible to distinguish between the hypothesis for absence of a major locus and absence of polygenic inheritance in the IDG group. Risks to develop the disease were calculated for a few typical situations.

Adolescent↗

Dye affinity adsorbent replacement optimization.

A method to determine the optimal replacement time for dye affinity adsorbents used in protein purification processes that are subjected to severe regeneration conditions has been developed. To demonstrate the utility of the method, an experimental fixed-bed decay model was employed to determine the optimum number of cycles for the adsorbent replacement. This number is a function of the column regeneration frequency and of the capital and operation costs. The implications of the results on the design and operation of dye-ligand chromatographic processes are discussed.

Adsorption↗