A single-tube technique for serum total iron and total iron binding capacity

A longitudinal study of unsaturated iron-binding capacity and lactoferrin in unstimulated parotid saliva

Availability of iron is one important nutritional parameter for microbial growth in saliva. This longitudinal study measured the diurnal and day-to-day variations in the total iron (TI), total iron-binding capacity (TIBC), unsaturated iron-binding capacity (UIBC), and lactoferrin (LF) in unstimulated human parotid saliva. Saliva was collected from 15 young male subjects in the morning and afternoon hours each day for five consecutive days. The TI and TIBC were determined by flameless atomic absorption spectroscopy, and UIBC was determined by subtraction of TI from TIBC. The LF was determined by "sandwich" enzyme-linked immunosorbent assay (ELISA). One peripheral blood sample of each subject was also analyzed for TI, TIBC, and ferritin. The results showed no significant diurnal or day-to-day variation of TI, TIBC, UIBC, or LF in saliva for most subjects. However, significant between-subject variations were observed for most parameters. Variations ranged from subjects with constantly positive UIBC values to subjects with constantly negative UIBC values. The relationship between the LF values and the TI and TIBC values suggests that other iron-binding protein(s) are present in saliva. Also, saliva had significantly lower TIBC values than serum. This finding indicated that iron may be easily available in saliva. However, further studies are required to determine the relationship between UIBC value of saliva and oral and dental diseases, and also to detect the presence of other iron-binding proteins in saliva.

Effects of in utero and postnatal sodium saccharin exposure on the nutritional status of the young rat. II. Dose response and reversibility

A previous study in our laboratory demonstrated that 30-day-old Sprague-Dawley rats exposed to 7.5% sodium saccharin (NaS) since conception differ from untreated rats in several physiological parameters. In the present study, to determine the dose response of the changes associated with NaS treatment, animals were evaluated at 30 days post-birth, after treatment with dietary levels of 0, 1, 3 or 7.5% NaS since conception. Most physiological consequences of NaS treatment in the weanling rat, including anaemia and reductions in serum folate and vitamin A concentrations, were dose dependent. Serum vitamin E, cholesterol and triglyceride concentrations were decreased at the two lower doses of NaS but were significantly increased with 7.5% NaS. The no-effect level (NOEL) was similar for physiological effects and for bladder tumour production in two-generation studies (1% NaS in the diet). The reversibility of the effects of 7.5% NaS was examined in 90-day-old rats. The increases in lipids and vitamin E were reversible. Although values for haematological parameters and serum vitamin A remained significantly reduced at 90 days, changes were less severe than at 30 days. Histological examinations revealed that the effects of 7.5% dietary NaS on the bladder were negligible, indicating that the physiological changes observed in the young rat are probably not directly related to the production of bladder tumours.

The rise in the total iron-binding capacity after iron overdose

STUDY OBJECTIVES

To determine if and to what extent the total iron-binding capacity (TIBC) would increase following an iron overload, and to identify specific iron-binding proteins that might be responsible for the increased TIBC.

DESIGN

A prospective laboratory investigation.

SETTING

A certified regional poison control center.

PARTICIPANTS

Six healthy adult male volunteers.

MEASUREMENTS AND MAIN RESULTS

All volunteers ingested 20 mg/kg of elemental iron. Blood samples were drawn at hourly intervals for eight hours and analyzed for serum iron, TIBC, transferrin, ferritin, lactoferrin, glucose, bicarbonate, and WBC. Within two hours of ingestion, subjects developed symptoms of toxicity, including nausea, lightheadedness, vomiting, severe crampy abdominal pain, and voluminous diarrhea. The TIBC was statistically significantly increased at all points measured from one to six hours. Despite rising above 300 micrograms/dL in five of six subjects, the serum iron never exceeded the TIBC in any subject. Transferrin and ferritin did not increase to account for the increased TIBC. The lactoferrin levels did increase, but they did not correlate with significant increases in the TIBC.

CONCLUSIONS

Twenty mg/kg of elemental iron caused clinical toxicity in this study, and after iron overload the colorimetric TIBC increased by unknown mechanisms.

Iron absorption in the thalassemia syndromes and its inhibition by tea

To determine the hemoglobin concentration at which iron absorption is minimal, five subjects with thalassemia major and one with thalassemia intermedia underwent a series of iron-absorption studies. The effect of tea as an inhibitor of non-heme iron absorption was also tested. Iron absorption increased as the hemoglobin concentration decreased, although iron absorption was much higher at any given hemoglobin level in the subject with thalassemia intermedia. In the subjects with thalassemia major, iron absorption averaged 10 per cent at hemoglobin concentrations between 9 and 10 and 2.7 per cent between 11 and 13 g per deciliter. The percentage of iron absorbed could be accurately predicted from the nucleated red-cell count (r = 0.91, P less than 0.001). Tea produced a 41 to 95 per cent inhibition of iron absorption. Since patients with thalassemia intermedia may absorb a large percentage of dietary iron, inhibitors of iron absorption, such as tea, may be useful in their management.