In vivo labelling of RBC with 99mTc for blood pool imaging using different stannous radiopharmaceuticals.

The in vivo 99mTc-RBC labelling efficiency and stability of labelling was assessed after pretinning with a high-stannous content DTPA kit (Sn DTPA) in comparison with Sn-pyrophosphate (Sn PPi) and a low-stannous DTPA kit (DTPA). The distribution in Sprague Dawley rats showed that similar fractions of administered 99mTc remained within the blood pool after pretinning with Sn DTPA and Sn PPi when equal quantities of stannous ions (15 micrograms/kg) and equal time intervals (30 min) between successive IV injections of pretinning agent and 99mTc-pertechnetate were used. Significantly lower fractions were found when DTPA (1.9 micrograms Sn2+/kg) was used for pretinning. The rate of 99mTc elution emphasises the importance of the Sn2+ concentration used, not only for labelling efficiency but also for stability of the labelling. Satisfactory intravascular activity, exceeding 80% during the first hour post-injection, was demonstrated in three volunteers after 99mTc injection, when Sn DTPA was used for pretinning. Left ventricular ejection fractions (LVEF) measured by equilibrium radionuclide angiography after pretinning with Sn DTPA in 24 patients correlated well (r = 0.98) with those obtained by contrast angiographies over a broad spectrum of values (0.14-0.72). Four repeated LVEF measurements at 45-min intervals in six additional patients at rest showed excellent reproducibility in each patient: maximum variation was less than 6%.

Chromosome aberrations induced by occupational exposure to mercury.

The incidence of chromosome aberrations was studied by peripheral blood incubation (52 hr, the last 4 hr in the presence of Colcemid) using a modification of the Evans' technique in twenty-two men exposed to either vapors of metallic mercury (Group I) or organic mercury (Group II). Mercury concentrations of the work areas frequently exceeded the Maximum Allowable Concentrations in the past. During the year proceding the investigation, mercury values ranged between 0.15 and 0.44 mg/m3. None of the investigated men were poisoned, but all had had repeated increased mercury absorption with urinary eliminations reaching 890 microgram/l and 896 microgram/l for subjects in Groups I and II, respectively. The incidence of chromosome aberrations was significantly higher (P less than .001) in subjects exposed to mercury as compared with a control group (ten subjects) of a similar mean age. There was no statistical difference in the incidence of chromosome aberrations between men belonging to Groups I and II. Although an increase of both chromatid gaps and breaks was noticed in exposed men, the incidence did not significantly differ from controls. No chromatid interchanges were recorded and no difference between exposed and control subjects was noticed concerning the frequency of aneuploid or polyploid cells.

Reproductive ability of workmen occupationally exposed to lead.

The reproductive ability of 150 men occupationally exposed to lead were studied by clinical and toxicological analysis. Subjects were divided into four groups: lead-poisoned workmen (23) and those showing a moderate (42), slight (35), or physiologic absorption (50). Findings show that (1) Lead poisoning as well as moderate increased absorption of lead decrease the fertile ability of men. An increased frequency of asthenospermia, hypospermia, and teratospermia have objectified the decrease. (2) Slight increased or physiologic absorption of lead do not significantly influence the fertile ability of workmen. (3) Hypofertility induced by lead is due, perhaps, to its direct toxic effect on the gonads, as no interference with the hypothalamopituitary axis were evidenced.