Zinc absorption from a low-phytic acid maize

BACKGROUND: Phytic acid reduction in cereal grains has been accomplished with plant genetic techniques. These low-phytic acid grains provide a strategy for improving the mineral (eg, zinc) status in populations that are dependent on grains, including maize (Zea mays L.), as major dietary staples. OBJECTIVE: The objective was to compare the fractional absorption of zinc from polenta prepared from maize low in phytic acid with that prepared from a wild-type isohybrid maize (control) after short-term consumption by adults whose habitual diet is low in phytic acid. DESIGN: Healthy adults served as their own control subjects in a crossover design. All meals on 1 d consisted of polenta prepared from a low-phytic acid maize homozygous for the recessive low phytic acid 1-1 (lpa1-1). On the preceding or following day, all meals consisted of polenta prepared from a sibling isohybrid homozygous wild-type maize with a "normal" phytic acid content. The low-phytic acid maize contained approximately 60% less phytic acid than did the wild-type maize. All test meals were extrinsically labeled with zinc stable-isotope tracers. The fractional absorption of zinc was determined on the basis of fecal enrichment. RESULTS: The molar ratios of phytic acid to zinc in the polenta prepared from lpa1-1 maize and the wild-type maize were 17:1 and 36:1, respectively. The corresponding fractional absorptions of zinc were 0.30 +/- 0.13 and 0.17 +/- 0.11, respectively (P < 0.005). CONCLUSION: Substitution of a low-phytic acid grain in a maize-based diet is associated with a substantial increase in zinc absorption.     

The Contraceptive Diaphragm Is it an Acceptable Method in the 1980s?

A prospective study of diaphragm users at the Family Planning Association of Victoria was undertaken. Despite the women being well motivated and instructed the pregnancy rate was high (24 per 100 woman years) and the continuation rate was only 35% at 12 months. Three-quarters of the women who became pregnant admitted that they did not use a diaphragm on every occasion. Therefore emphasis must be placed on the committed use of the diaphragm every time coitus occurs. Even so, the diaphragm does not appear to be a very safe method of contraception, and may be better suited to family spacing rather than as a method when high efficacy is required.     

Microbiological Profile of the Cervix in 1,000 Sexually Active Women

One thousand consecutive women who attended the Richmond Family Planning Association Clinic and who were to undergo a vaginal examination were asked to participate in a large prospective microbiological study. Participants were questioned about their sexual activity during the previous 12 months and any apparent signs of sexually transmitted disease. On examination the cervix was inspected for evidence of inflammation, ectopy or discharge and cervical swabs were taken microbiological assessment. Chlamydia trachomatis was isolated in 5.1% of women tested while Ureaplasma urealyticum and Mycoplasma hominis were found in 48.8% and 16.4% of women respectively. Significant associations were found between the number of sexual partners during the previous 12 months and the incidence of all 3 organisms. The carriage rate of the genital mycoplasmas was significantly affected by the type of contraception. In addition the association between the presence of the genital mycoplasmas and pelvic and cervical abnormalities was determined.     

Interrelationships between PGE1 and PGI2 binding and stimulation of adenylate cyclase

The effects of prostaglandin E1 (PGE1) and prostacyclin (PGI2) on hepatic adenylate cyclase were studied in plasma membranes isolated from Sprague-Dawley rat livers. Both PGE1 and PGI2 stimulated this enzyme complex to the same maximal levels and with approximately the same EC50 (10(-7) M). Maximally stimulating concentrations of PGE1 and PGI2 were examined alone and together; their effects were not additive, indicating that the same enzyme complex was shared. Although a receptor for PGE1 could be demonstrated with a dissociation constant of 1 X 10(-8) M, PGI2 was only 1/100 as effective in competing for PGE1 binding sites (KD, 1 X 10(-6) M), indicating that these two prostaglandins may act via separate membrane receptors. PGI2 is known to be unstable at neutral pH; however, we have determined its half-life during these assays by a sensitive bioassay and concluded that the degradation of PGI2 is not sufficient to account for its inability to dissociate [3H]PGE1 binding. Further evidence that PGI2 might act through a distinct receptor was found in animals whose PGE1 receptors were 40% downregulated with a corresponding 28% decrease in PGE1-sensitive adenylate cyclase activity. These membranes had no such decrease in PGI2-sensitive adenylate cyclase activity. We conclude that 1) hepatic adenylate cyclase is equally sensitive to PGE1 and PGI2; 2) the same adenylate cyclase complex responds to both prostaglandins; and 3) PGE1 and PGI2 interact with separate membrane receptors in rat liver.     

Alterations in eicosanoid production by rat alveolar type II cells isolated after silica-induced lung injury.

Although alveolar type II cells in primary culture have been shown to produce eicosanoids and exposure of type II cells to silica in vitro alters eicosanoid production, the production of eicosanoids by alveolar type II cells isolated after acute lung injury in vivo has not been evaluated. Therefore, we investigated the production of arachidonic acid (AA) metabolites by alveolar type II cells isolated after silica-induced lung injury. Alveolar type II cells were isolated from rats 14 days after intratracheal silica instillation and from untreated animals. Type II cells were separated into normotrophic and hypertrophic populations by centrifugal elutriation, and secreted eicosanoids were determined under basal and stimulated conditions by enzyme immunoassay on the day of isolation and after 1 day in culture. Under basal conditions, freshly isolated type II cells from silica-treated animals produced more prostaglandin (PG) E2 than 6-keto-PGF1 alpha or thromboxane B2 (TxB2). Production of all three prostanoids increased with increasing cell size. The calcium ionophore A23187 stimulated a less than 2-fold increase in PGE2 and 6-keto-PGF1 alpha production in all groups of cells. In contrast, this calcium ionophore greatly enhanced TxB2 and leukotriene C4 (LTC4) production by normotrophic type II cells from both untreated and silica-treated animals. Incubation with exogenous AA suggested that the increased capability of the hypertrophic cells to synthesize PGE2 and TxB2 was due primarily to an increase in arachidonate availability. The hypertrophic type II cells also appear to have increased prostacyclin synthase activity. There were no differences in the catabolism of PGE2 between the normotrophic and the hypertrophic type II cells.(ABSTRACT TRUNCATED AT 250 WORDS)     

Traction bronchiectasis in end-stage pulmonary fibrosis

Postmortem examination of the lungs of 12 patients with end-stage pulmonary fibrosis revealed the frequent (nine of 12) presence of bronchiectasis. The segmental and subsegmental bronchi were dilated, tortuous, and had a convoluted appearance that resembled a string of pearls. Bronchiectasis was confined to areas of advanced fibrosis. When fibrosis was mild or when it was combined with emphysema, bronchiectasis was absent or mild. Specimen radiographs revealed that bronchiectasis frequently contributed to the radiographic appearance of honeycombing. Retrospective analysis of the plain chest radiographs obtained from five of the patients revealed evidence suggestive of bronchiectasis, but bronchiectasis was difficult to detect unless the surrounding lung was radiopaque. In two living patients with end-stage pulmonary fibrosis, bronchiectasis was much better depicted on computed tomography scans than on plain chest radiographs. In patients with pulmonary fibrosis, the presence of bronchiectasis does not necessarily imply the presence of primary bronchial disease. Rather, bronchiectasis can be a direct result of the fibrotic process.     

Peripheral pulmonary lesions: ultrasonography and ultrasonically guided aspiration biopsy

Twenty-five patients, each of whom had peripheral intrathoracic lesions that were smaller than 5.0 X 5.0 cm in size and not diagnosed by conventional methods, underwent real-time sonography and ultrasonically guided aspiration biopsy. The lesions included 18 nodules, two infiltrates, and five cavitary lesions. Sonography showed homogeneous hypoechoic or isoechoic density with well-defined margins in 16 of the nodules, and heterogeneous echogenicity with irregular margins in infiltrates. The cavitary lesions showed a hyperechoic ring with a central sonolucent area. Biopsy specimens were successfully obtained by percutaneous aspiration under ultrasound guidance in 24 (96%) of the patients, and a positive diagnosis was established in 21 (84%) by cytology and/or histology. All 17 malignant lesions were diagnosed by aspiration biopsy, while only four of seven benign lesions were diagnosed by this method. Two patients (8%) experienced minimal pneumothorax after aspiration biopsy. We conclude that real-time sonography, including ultrasonically guided aspiration biopsy, is a useful and safe method for examination of peripheral intrathoracic lesions and has a high diagnostic yield.     

Depo Provera: A Profile of Current Users

This retrospective study reviewed the current users of Depo-Medroxy-Progesterone-Acetate (Depo-Provera) from April to June, 1987, within the Family Planning Association of Victoria's Richmond Clinic. The profile that emerged from the study showed the clients were of average intelligence, well informed, had tried other methods of contraception, had a high number of unplanned pregnancies and chose to use Depo-Provera as other methods of contraception were unsuitable.     

Absorption of calcium from tortilla meals prepared from low-phytate maize

BACKGROUND: Calcium fortification of maize has been achieved for millennia in Central America by the process of nixtamalization. Bioavailability of calcium is, however, compromised by phytate, which is present in large quantities in maize kernels and is only modestly reduced by nixtamalization. OBJECTIVE: The objective was to compare the absorption of calcium from tortilla meals prepared from low-phytate maize with that from meals prepared from maize with typical phytate content. DESIGN: At 1-mo intervals, 5 healthy adult women were fed 2 test meals of approximately 140 g tortillas in lieu of breakfast. On one occasion, the tortillas were prepared from maize with approximately 60% phytate reduction, and, on the other occasion, they were prepared from the matching isohybrid wild-type maize. Beginning midway through the test meal, (44)Ca (0.3 mg/kg body wt) was administered in water as an extrinsic label; (42)Ca (0.06 mg/kg body wt) was administered intravenously immediately after the test meal. Isotope ratios of (42)Ca to (43)Ca and of (44)Ca to (43)Ca were measured by inductively coupled plasma mass spectrometry in urine collected as an 8-h pool from the period 16-24 h after intravenous tracer administration and prepared by the oxalate precipitation method. Fractional absorption of calcium was determined by using a dual-isotope ratio technique. RESULTS: Mean fractional absorption of calcium from tortillas prepared from the low-phytate maize (0.50 +/- 0.03) was significantly (P = 0.003) greater than that from tortillas prepared from the control maize (0.35 +/- 0.07). CONCLUSION: The increase in the quantity of calcium absorbed could be of practical importance for calcium nutriture when the intake of dairy products is limited.