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Biomedical subjects

R Fernandez

Publications and source records attributed to R Fernandez.

At least 145 records · Page 8Linked to original sources

Components of fiber bind iron in vitro.

Interactions among fiber, inorganic iron, and substances known to chelate iron were examined in vitro. Cellulose, neutral and acid fractions of lignin, psyllium mucilage, and pectin were incubated with 59Fe SO4 at various pH's, in various concentrations, and in the presence or absence of known chelators of iron including ascorbate, citrate, cysteine, fructose, and EDTA. Insoluble components of fiber were tested in a precipitation-centrifugation system, soluble components were tested by equilibrium dialysis. Lignins and psyllium mucilage had the greatest capacity to bind ferrous iron under conditions that approximated those of the proximal intestine postprandially; cellulose and pectin were less potent. Dissociation constants of binding were similar for several components, suggesting the existence of comparable binding sites in different components of fiber. Citrate and EDTA inhibited the binding of iron markedly but other chelators were much less effective. These reactions among fiber, inorganic iron, and other constituents of food may influence the bioavailability of dietary iron and the simple systems described here offer a means of dissecting interactions that are complex in vivo.

Cellulose↗

Components of fiber impair iron absorption in the dog.

We have demonstrated previously that semipurified components of fiber bind ferrous iron in vitro. The present studies examined the possibility that these same fibers would decrease absorption of iron by the canine small bowel. Healthy and anemic dogs were studied chronically. Two preparations were needed; soluble components of fiber were tested by continuous perfusion of a duodenojejunal segment of approximately 100 cm, insoluble components were tested in Thiry-Vella fistulae of jejunum (25 cm). The results confirm that, 1) anemic dogs absorb iron more efficiently than do healthy animals, and 2) that there is a slight, but significant, decrease in iron absorption during the 4 to 6 h of an acute experiment. To obviate problems of interpretation because of the latter point, all studies featured a control period, before and after, the test period. Lignin and psyllium mucilage were potent inhibitors of iron absorption, pectin less so, and cellulose was without effect in this system. The results in vivo correlate well with the binding of iron in vitro.

Anemia, Hypochromic↗

Ureteral diverticulosis in a case of dermatomyositis.

We present the third case of ureteral diverticulosis discovered by excretory urography alone and the twenty-sixth case reported in the world literature. Unlike previously reported cases our patient had dermatomyositis and is urologically asymptomatic.

Dermatomyositis↗

[Plea for better terminology in surgery of the profunda femoris artery (author's transl)].

Surgical publications on the profunda femoris artery rarely give information on the site of the operation and the technic used. Experience of 356 operations carried out from 1949 to 1978 by the authors and anatomical dissection of 100 profunda femoris arteries is reported. They suggest the elimination of all imprecise terms at present attached to these operations and their replacement by a more lengthy but more understandable vocabulary, together with an attempt to classify the profunda femoris artery in two groups and its nomenclature in 4 segments, more adaptable to surgery of this artery.

Aged↗

The significance of serial measurements of serum complement C3 and C4 components and DNA binding capacity in patients with lupus nephritis.

Eighteen patients with systemic lupus erythematosus (SLE) and proliferative glomerulonephritis, underwent serial serum determinations of C3, C4, and native DNA binding capacity, as well as repeat renal biopsy 7 to 48 months (median 25 months) following initial biopsy. Highly significant correlations were found between serum C3 levels and renal histologic changes (P less than 0.0001), and between serum C3 levels and DNA binding capacity (P less than 0.03). Histologic deterioration correlated with depressed C3 levels, while improvement was associated with normalization of C3 levels. No correlation between renal histologic changes and either serum C4 levels or DNA binding capacity was found. The data suggest that the serum level of C3 is the best index of activity of lupus nephritis.

Adolescent↗

[Growth and morphologic characteristics of normal human endometrial cells in primary culture].

Monolayer cultures of endometrium were established from 59 normal women after hysterectomy. The technical procedure is described, allowing cells in monolayer to grow satisfactorily for more than 60 days, showing a doubling-time of about 4-5 days. During early passages, two cell populations are characterized by microscopic examination : confluent areas of epithelial polygonal cells and scattered fusiform fibroblastic cells. After the 8th passage, epithelial cells are no longer recognized : the monolayer is homogeneous and all cells are fibroblast-like. These cells are an interesting model system for steroid sex hormone studies.

Cell Division↗

Effects of sulfuric acid aerosol on cardiopulmonary function of dogs, sheep, and humans.

Submicronic aerosol of sulfuric acid (H2SO4) originates from the burning of fossil fuels and discharge of vapor from the automobile engine equipped with the catalytic converter. This study was conducted to determine whether brief exposure to this aerosol in high concentrations adversely affects the cardiopulmonary system. In all studies, submicronic aerosol of sodium chloride was used as a control. Anesthetized dogs that breathed H2SO4 aerosol in concentrations up to 8 mg per m3 showed no effects on respiratory resistance, static lung compliance, and functional residual capacity. A 4-hour exposure to H2SO4 aerosol (4 mg per m3) produced no significant changes in mechanics of breathing, functional residual capacity, pulmonary and systemic arterial blood pressures, cardiac output, heart rate, and arterial blood gas tensions. Conscious sheep that breathed H2SO4 aerosol in concentrations up to 14 mg per m3 for 20 min had no alteration of tracheal mucous velocity in an immediate 3-hour follow-up period or 5 to 10 days later. Conscious sheep that breathed H2SO4 aerosol (4 mg per m3) for 4 hours had no significant alteration of tracheal mucous velocity immediately and 2 hours thereafter. Both normal and asthmatic adults breathing H2SO4 aerosol in concentrations up to 1 mg per m3 for 10 min showed no significant alteration of lung volumes, distribution of ventilation, ear oximetry, dynamic mechanics of breathing, oscillation mechanics of the chest-lung system, pulmonary capillary blood flow, diffusing capacity, O2 consumption, and pulmonary tissue volume. No delayed effects in pulmonary function nor exacerbation of bronchial asthma were observe during a follow-up period of a few weeks. The present study indicates that single exposure to submicronic H2SO4 aerosol does not produce an immediate or a delayed adverse effect on cardiopulmonary function in anesthetized dogs, conscious sheep, and normal and asthmatic adults.

Aerosols↗