Magnesium, zinc and copper in plasma and blood cellular components in children with IDDM.

The levels of magnesium (Mg), zinc (Zn) and copper (Cu) in the plasma, erythrocytes (RBC) and polymorphonuclear (PMN) and lymphocyte (L), leukocytes (WBC) of 45 diabetic children were compared to those of 12 normal children and were related to the diabetic control via HbA1 and fasting blood sugar (FBS) assessments. Mineral levels were determined via Zeeman-effect atomic absorption spectrophotometry following separation of plasma, RBC, and WBC fractions (PMN vs. M). ANOVA (four-way, blood components, by two-way, diabetic vs. normal children) was significant for Mg only (F = 4.60, P < 0.004). Plasma Mg and M-WBC Mg were significantly lower in children with diabetes (780 +/- 16 vs. 860 +/- 29 mumol/l and 519 +/- 33 vs. 866 +/- 86 micrograms/10(10) cells, respectively). RBC Zn was significantly lower in diabetic youngsters by t-test (0.48 +/- 0.012 vs. 0.57 +/- 0.046 per mumol/g Hgb, t = 2.79, P < 0.004), but the ANOVA for Zn was not significant. Cu level differences were not significant. HbA1 was predicted only by PMN-WBC Mg (F = 8.78, P < 0.04) and FBS by none. In conclusion, the mineral status of these diabetic children was altered in regard to Mg, but was mainly independent of diabetic control.

Change in hen sciatic nerve calcium after a single oral dose of tri-o-tolyl phosphate.

Six trace elements were monitored in neural tissue homogenates from White Leghorn hens orally dosed with tri-o-tolyl phosphate (TOTP) or tri-m-tolyl phosphate (TMTP) (200 mg/kg). Treated birds were monitored daily for development of delayed neurotoxicity, and concentrations of calcium, copper, iron, magnesium, manganese, and zinc were measured with atomic absorption spectroscopy at the time of maximal locomotor impairment (27-35 days postdosing). TOTP-treated birds manifested motor deficit by 15 days postdosing, while hens administered TMTP exhibited no signs of delayed neurotoxicity. Total calcium content in the sciatic nerve homogenates from TOTP-dosed hens was significantly less (P < 0.05) at the time of maximal locomotor impairment, while no shifts in the other trace elements were found. Therefore, the ortho isomer of tritolylphosphate elicited symptoms of delayed neurotoxicity in the hen (i.e., organophosphorus ester-induced delayed neurotoxicity or OPIDN) and caused a decrease in total calcium content in the sciatic nerve homogenates, in contrast to effects of the meta isomer. Analysis of neural homogenates at time of maximal locomotor impairment reflected secondary events in the degradative processes, since the initial assault of TOTP happens early after administration. Therefore, at fully developed OPIDN alteration of calcium balance in sciatic nerves is an indicator of axonopathy in a degenerated nerve following chemical injury.

Residential exposure to chromium waste--urine biological monitoring in conjunction with environmental exposure monitoring.

To determine whether a population living on or adjacent to four sites of chromate production waste was measurably exposed to environmental chromium, spot samples of urine were collected along with wipe samples of household dust and lifestyle/activity interview data. Findings were compared to those from a control population in two communities with no significant chromium use or waste sites. Urine samples were collected and analyzed, employing measures to minimize background chromium contamination. The average Cr mass in dust was 3.7 times that in control houses. The mean creatinine-corrected urine Cr (Cr/c) level of the exposed subgroup residing in households in the 75th percentile of Cr mass in wipe samples was significantly greater than that of the control population. This subgroup was primarily located at a single exposure location. Using lifestyle/activity data, significantly elevated Cr/c urine levels were identified in other exposed subgroups defined by employment location and by outside play time. These data show an association between elevated exposure to chromium in household dust and elevated urine levels of chromium, consistent with residential exposure to chromate production waste. These data also suggest an association between chromium exposure and activities outside the home which are consistent with exposure to chromate production waste.

Effect of lactose on mineral absorption in preterm infants.

To determine whether a reduction of dietary lactose affects mineral absorption in preterm infants, a controlled, randomized, 72-hour balance study was conducted with very low birth weight infants (birth weights less than 1400 gm) fed Similac Special Care formula with a 50:50 carbohydrate blend of glucose polymers and lactose (n = 8) or a nearly identical formula with 100% carbohydrate as lactose (n = 10). The studies were conducted after at least 3 consecutive days of full oral feeds at a mean age of approximately 23 days. There was no difference between groups in percentage of apparent absorption of calcium, phosphorus, magnesium, zinc, copper, or manganese. Retention of these nutrients was similar to or greater than that which occurs in utero. Calcium absorption was 75% of intake. These results indicate that reducing the lactose content of premature-infant formulas to 50% of the carbohydrate does not impair mineral absorption.

Studies with nonradioisotopic sodium chromate. I. Development of a technique for measuring red cell volume.

A nonradioisotopic method for measuring red cell volume that involves the use of 52Cr-sodium chromate as the red cell label and of graphite furnace atomic absorption analysis of chromium is described. The technique allows the labelling of 20 mL of packed red cells with 40 to 50 micrograms of sodium chromate (Na2CrO4) in 30 minutes at 22 degrees C with 94 +/- 6 percent uptake. Approximately 40 micrograms of Na2CrO4 was injected for in vivo studies. This results in posttransfusion in vivo red cell chromium levels after sample processing in the range of 1 to 7 micrograms per L, which could be quantitated accurately (coefficient of variation = 4.7%) by Zeeman electrothermal atomic absorption spectrophotometry. The labeling concentration of chromium did not cause increased hemolysis, and the labeled cells exhibited an osmotic fragility curve similar to that of unlabeled, fresh ACD red cells. Red cell glutathione peroxidase was unaffected by labeling, although glutathione reductase was reduced by approximately 13 percent (p less than 0.05). The 52Cr red cell volume-measuring method was evaluated by concurrent in vivo studies with the standard 51Cr and 125I-albumin methods for that procedure. Simultaneous measurement of red cell volumes in seven volunteers by the 51Cr, 52Cr, and 125I-albumin techniques correlated highly with each other (r greater than 0.76), with mean values of 2294 +/- 199, 2191 +/- 180, and 2243 +/- 291 mL, respectively. The standard deviations of the differences were small: 134 mL for 52Cr versus 51Cr and 183 mL for 52Cr versus 125I.(ABSTRACT TRUNCATED AT 250 WORDS)

Studies with nonradioisotopic sodium chromate. II. Single- and double-label 52Cr/51Cr posttransfusion recovery estimations.

A recently developed nonradioisotopic 52Cr technique was used to measure either red cell volume or posttransfusion recovery of stored red cells. The experimental method uses Zeeman electrothermal atomic absorption spectrophotometry to measure red cell chromium. Results from the 52Cr method were compared with those from 51Cr single-label and 125I-albumin/51Cr double-label procedures using 49-day AS-1 red cell concentrates drawn and prepared according to standard procedures. In the first group of five donors, red cell volume was estimated concurrently with both 52Cr-labeled fresh red cells and 125I-albumin. The latter measured plasma volume from which red cell volume was estimated on the basis of the hematocrit (125I red cell volume). 51Cr-labeled stored red cells were transfused to measure posttransfusion recoveries. The correlation between 52Cr and 125I red cell volumes was significant (r = 0.68, p less than 0.01), and, in this group, the differences were not significant (p less than 0.05). Twenty-four-hour posttransfusion recoveries of 51Cr-labeled stored red cells averaged 66 +/- 5 percent when measured with the 125I/51Cr technique and 69 +/- 8 percent when measured with the 52Cr/51Cr method. In the second group of five donors, red cell volume was estimated by the 125I-albumin technique, and the posttransfusion recovery of stored red cells was quantitated by 51Cr- and 52Cr-labeled stored cells simultaneously. In this group, posttransfusion recoveries with 125I/51Cr averaged 73 +/- 7 percent; with 125I/52Cr, they averaged 75 +/- 10 percent. Using the single-label method of calculation, recoveries averaged 76 +/- 7 and 75 +/- 10 percent for the 51Cr and 52Cr methods, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Correlation between sperm morphology, acrosin, and fertilization in an IVF program.

Acrosin, a neutral proteinase, is located within the acrosome. The aim of this study was to evaluate acrosin concentrations in patients with severe damage of the sperm head and to determine whether acrosin concentration could predict the chances of fertilization in an IVF program. Sixty patients were accepted into this study, prospectively. The patients were divided into two groups, those with a normal morphology of less than 14% (group I, n = 33) and those with normal morphology less than 14% (group II, n = 27). All patients had a sperm concentration of less than 20 million sperm/ml and less than 30% progressively motile sperm. The acrosin assays were performed on the semen sample obtained on the day of IVF. Routine IVF insemination procedures were used, and only mature oocytes were considered. The only factor that showed a significant correlation of fertilization was normal morphology (p less that 0.01). The mean acrosin level was 73.4 /+- 38.6 mED/10 million sperm in group I and 70.9 /+- 42.7 mIU/10 million sperm in group II (no significant difference). The fertilization rate in group I was 45.4% and in group II, 77.7% p less than 0.002). Acrosin levels were not significantly different in patients with and without fertilization (72.0 /+- 42.1 and 73.6 /+- mIU/10 million sperm, respectively).

Effect of acute tri-o-tolyl phosphate exposure on 2', 3'-cyclic nucleotide 3'-phosphohydrolase activity in hen neural tissues.

The activity of 2', 3'-cyclic nucleotide 3'-phosphohydrolase (CNP, EC 3.1.4.37), a myelin-associated enzyme, was monitored in brain, spinal cord, and sciatic nerve homogenates from tri-o-tolyl phosphate (TOTP) and tri-m-tolyl phosphate (TMTP) treated hens. Atropinized adult White Leghorn hens were orally dosed with TOTP (200 mg/kg) or with TMTP (200 mg/kg). The treated birds were monitored daily for development of delayed neurotoxicity, and CNP activity was measured via spectrophotometry at the time of maximal locomotor impairment (27-35 days post dosing). The TOTP-treated birds manifested locomotor deficit by 15 days postdosing and exhibited T2-T4 ataxia at maximal locomotor impairment. The hens administered TMTP exhibited no signs of delayed neurotoxicity. CNP activity of sciatic nerve preparations from TOTP-dosed hens was significantly inhibited (p less than 0.05) at the time of maximal locomotor impairment. There was also a significant correlation between decreased CNP activity and the degree of ataxia at the time of maximal locomotor impairment. This decrease in sciatic nerve CNP activity was most likely associated with nerve fiber degeneration. The level of CNP activity in spinal cord and brain homogenates from TOTP-dosed birds was not markedly altered. TMTP-treated birds exhibited no change in neural tissue CNP activity. The results suggest that the criterion of decreased CNP activity may serve as a useful biochemical adjunct to established clinical, biochemical, and morphological methods in the assessment of chemically-induced neuropathies.

Kinetic immunonephelometric determination of protein concentrations in follicular fluid.

Nonsteroidal biochemical markers of oocyte maturity could presumably aid in oocyte selection and in the timing of insemination for in vitro fertilization. We assessed the usefulness of six potential markers found in follicular fluid. We used kinetic immunonephelometry to measure concentrations of alpha 1-antitrypsin, alpha 2-macroglobulin, antithrombin III, ceruloplasmin, fibrinogen, and plasminogen in 53 fluids and the corresponding plasma from 20 women undergoing in vitro fertilization. Specimens were obtained from both mature and immature follicles from each woman. The respective protein concentrations in follicular fluid could be assayed with a between-assay CV of 1.5% to 3.2%. Analytical-recovery studies indicated that only fibrinogen and antithrombin III concentrations were altered (by 120% and 75%, respectively) during aspiration of the follicle into saline. All protein concentrations were significantly increased in mature follicles, as were the follicular fluid:plasma concentration ratios for alpha 1-antitrypsin, antithrombin III, and ceruloplasmin.

Trace element metabolism in the fetus and neonate.

The effects of trace metal nutrition on the fetus and neonate have been described. Since very little research has been done with the human fetus and neonate, much of our knowledge must be extrapolated from animal studies. In addition, most of the work centres around the effects of copper and zinc nutrition. Nutritional requirements (when known) for both enteral and total parenteral feeding of certain trace metals, as well as the bioavailability, have been discussed. Finally, methods of assessment of trace metal nutritional status have been discussed. These include direct measurement of metal concentrations and determination of biochemical indicators, such as metal-dependent enzyme activities--both of which are static indicators of nutritional status, and functional assessment of nutritional status which is a dynamic measure of trace metal nutrition and includes tests measuring the effects of metal nutrition on the function of cells, tissues, organs, and the host in general.

Selective disturbances of serum mineral profiles by electroconvulsive therapy.

In nine patients with severe affective illness, the serum profiles of Mn, Zn, Cu, Mg, and Ca before and following successful bitemporal electroconvulsive therapy (ECT) were investigated. No elemental baseline abnormalities were detected before ECT. Both high and low level electric stimulation failed to produce changes in the serum concentrations of Mg as a function of time after ECT. Group mean concentrations of Zn, Cu, and Ca decreased after ECT, but values did not reach statistical significance. In contrast high level, but not low level, stimulation was accompanied by significant brief elevation of Mn (65%, p less than .02) followed by a progressive drop below basal levels (67%, p less than .001) 2 hours post-ECT. Similar patterns were observed during the middle and last ECT. Pre-ECT baseline Mn concentrations declined by about 44% (p less than .01) after the last ECT administration. The time course of these changes, in conjunction with evidence obtained from animal experimentation, suggests that high level ECT, irrespective of the onset of antidepressant effects, may alter extracellular Mn and consequently its normal intracellular composition as a result of the sudden increase in energy expenditure imposed by convulsive activity. Possible interactions between this element and other metabolic pathways are discussed. These changes may originate from elemental participation in restorative homeostatic metabolic processes during and after ECT.

Kinetic nephelometric determination of transthyretin and retinol-binding protein in neonatal serum.

We have developed a kinetic immunonephelometric method for the determination of retinol-binding protein and modified the method of Jacob et al (Clin Chem 1983; 29: 564) for the determination of transthyretin (prealbumin) in neonatal serum specimens from small, premature infants. The methodologies allow detection of 17.5 mg/l transthyretin and 1.7 mg/l retinol-binding protein in 25 microliter of serum. Between-run precision studies using pooled neonatal serum gave CV values of 3% and 5-6% for transthyretin and retinol-binding protein, respectively. Results obtained for neonatal specimens using this method agreed well with those obtained for the same specimens using radial immunodiffusion. Mean (SD) serum concentrations for 39 neonatal specimens were 100.4 (46.6) and 26.3 (10.8) mg/l for transthyretin and retinol-binding protein, respectively.

Trace elements in human seminal plasma and spermatozoa.

Methodologies for the analysis of cadmium, copper, iron, lead, selenium and zinc in human seminal plasma and spermatozoa have been developed. Analyses were made directly in a dilution of seminal plasma or nitric acid digest of lyophilized cells using Zeeman-effect atomic absorption spectroscopy. Within-run coefficients of variation (CV's) for pooled specimens ranged from 0.5% to 9%. Between-run CV's ranged from 4% to 13%. Analysis of a seminal plasma specimen at 1/2, 1, 1 1/2, 3 1/2 and 5 hours post emission indicated that no change in seminal plasma trace element concentrations occurred on standing in contact with spermatozoa. Trace element concentrations were determined in specimens from patients undergoing infertility studies.

Determination of selenium concentration and glutathione peroxidase activity in plasma and erythrocytes.

We determined selenium concentrations and activities of the selenoenzyme, glutathione peroxidase (EC 1.11.1.9), in the plasma and erythrocytes of 38 apparently healthy women. We determined selenium concentrations directly by polarized Zeeman-effect flameless atomic absorption spectroscopy. Within-run precision studies for the assays gave CVs of 5.6% for a mean erythrocyte selenium concentration of 149.9 (SD 8.3) microgram/L (n = 10) and 6.4% for a mean plasma selenium concentration of 97.3 (SD 6.2) microgram/L (n = 12). For the women, mean selenium concentrations were 141.4 (SD 14.3) microgram/L of erythrocytes [0.49 (SD 0.07) microgram/g of hemoglobin and 96.3 (SD 14.2) microgram/L of plasma. Glutathione peroxidase activities were measured by a modification of the method of Paglia and Valentine (J. Lab. Clin. Med. 70: 158--169, 1967). Within-run precision studies for the glutathione peroxidase assays gave CVs of 12.8% for mean erythrocyte glutathione peroxidase activity of 77.2 (SD 9.9) U/g of hemoglobin (n = 13), and 8.1% for mean plasma activity of 312.5 (SD 25.2) U/L (n = 11). Mean enzyme activity was 78.7 (SD 12.9) U/g of hemoglobin for erythrocytes and 424 (SD 40) U/L for plasma. Erythrocyte selenium concentrations and glutathione peroxidase activities were positively, but poorly, correlated (r = 0.41, p less than 0.01).

Polarized Zeeman-effect flameless atomic absorption spectrometry of cadmium, copper, lead, and manganese in human kidney cortex.

We used polarized Zeeman-effect flameless atomic absorption spectroscopy to quantitatively measure cadmium, copper, lead, and manganese in a nitric acid digest of lyophilized human kidney cortex. Within-run coefficients of variation for cadmium, copper, lead, and manganese, 15.3, 177.2, 84.2, and 56.3 microgram/L, respectively, were 4.1, 6.3, 3.7, and 5.6%, respectively. Between-run coefficients of variation were 6.9, 5.5, 5.9, and 6.3%, respectively, for cadmium, copper, lead, and manganese concentrations of 135.1, 12.8, 2.72, and 3.80 microgram/g, respectively. For cadmium, copper, lead, and manganese digest concentrations (mean +/- SE) of 15.3 +/- 0.6, 41.4 +/- 2.6, 9.4 +/- 0.6, and 20.9 +/- 0.4 microgram/L, respectively, the detection limits were 5.2 microgram/L for copper, 1.2 microgram/L for both cadmium and lead, and 0.8 microgram/L for manganese. Assays were linear to 75 microgram/L for cadmium, 100 microgram/L for manganese, and 200 microgram/L for copper and lead. Average analytical recoveries for the four metals ranged between 95 and 101%. Because these metals were quantitated in the same digest of kidney cortex, the values for each digest gave a trace-metal profile for each autopsy specimen.

Determination of cadmium in whole blood and urine by Zeeman atomic absorption spectroscopy.

Direct determination of cadmium in whole blood and urine can be achieved using Zeeman effect flameless atomic absorption spectroscopy. Within-run precision studies for whole blood cadmium determinations gave relative standard deviations of 11.3% and 6.3% for 0.53 micrograms/l and 3.16 micrograms/l, respectively. Within-run precision studies for the urine analyses yielded relative standard deviations of 11.3% and 5.2% for 0.62 micrograms/l and 2.48 micrograms/l, respectively. The detection limit is 0.12 micrograms/l in the diluted specimens. Thus, this methodology may be used to quantitate normal and toxic cadmium levels in whole blood and urine.

Determination of manganese in whole blood and serum.

We describe methods for determination of manganese in whole blood and serum with Zeeman-effect flameless atomic absorption spectroscopy. These analyses are performed on a twofold or fourfold dilution of the specimen in Triton X-100, 1 g/L. No predigestion or extraction procedures are required. The method of standard additions was used for quantitation. Within-run coefficients of variation for whole-blood manganese were 7.0 and 5.5% for 2.29 and 5.67 micrograms/L, respectively. For determination of serum manganese, coefficients of variation were 10.3 and 5.3% for 0.97 and 3.01 micrograms/L, respectively. Manganese detection limits for the assays were 3.0 pg. Whole-blood manganese concentrations, determined for 60 subjects, yielded a mean (+/- SD) of 9.03 (+/- 2.25) micrograms/L. Mean serum manganese concentration, determined for 20 subjects, was 1.82 (+/- 0.64) microgram/L. No correlation was found between blood manganese concentrations and age, sex, or smoking status.