Investigations on the activity concentrations of 238U, 226RA, 228RA, 210PB and 40K in Jordan phosphogypsum and fertilizers.

The activity concentrations of naturally occurring radionuclides ((238)U, (226)Ra, (228)Ra, (210)Pb and (40)K) in Jordanian phosphate ore, fertilizer material and phosphogypsum piles were investigated. The results show the partitioning of radionuclides in fertilizer products and phosphogypsum piles. The outcome of this study will enrich the Jordanian radiological map database, and will be useful for an estimation of the radiological impact of this industrial complex on the immediate environment. The activity concentration of (210)Pb was found to vary from 95 +/- 8 to 129 +/- 8 Bq kg(-1) with a mean value of 111 +/- 14 Bq kg(-1) in fertilizer samples, and from 364 +/- 8 to 428 +/- 10 Bq kg(-1) with a mean value of 391 +/- 30 Bq kg(-1) in phosphogypsum samples; while in phosphate wet rock samples, it was found to vary between 621 +/- 9 and 637 +/- 10 Bq kg(-1), with a mean value of 628 +/- 7 Bq kg(-1). The activity concentration of (226)Ra in fertilizer samples (between 31 +/- 4 and 42 +/- 5 Bq kg(-1) with a mean value of 37 +/- 6 Bq kg(-1)) was found to be much smaller than the activity concentration of (226)Ra in phosphogypsum samples (between 302 +/- 8 and 442 +/- 8 Bq kg(-1) with a mean value of 376 +/- 62 Bq kg(-1)). In contrast, the activity concentration of (238)U in fertilizer samples (between 1011 +/- 13 and 1061 +/- 14 Bq kg(-1) with a mean value of 1033 +/- 22 Bq kg(-1)) was found to be much higher than the activity concentration of (238)U in phosphogypsum samples (between 14 +/- 5 and 37 +/- 7 Bq kg(-1) with a mean value of 22 +/- 11 Bq kg(-1)). This indicates that (210)Pb and (226)Ra show similar behaviour, and are concentrated in phosphogypsum piles. In addition, both isotopes enhanced the activity concentration in phosphogypsum piles, while (238)U enhanced the activity concentration in the fertilizer. Due to the radioactivity released from the phosphate rock processing plants into the environment, the highest collective dose commitment for the lungs was found to be 1.02 person nGy t(-1). Lung tissue also shows the highest effect due the presence of (226)Ra in the radioactive cloud (0.087 person nGy t(-1)).

Oxytocin release and lactation performance in Syrian Shami cattle milked with and without suckling.

Oxytocin (OT) release and lactation performance in primiparous Syrian Shami cows were evaluated in response to two different machine milking regimes. Six cows were milked in the presence of the calves (PC) and subsequently suckled, whereas six cows were exclusively machine milked without the presence of their calves (WC) until day 91 post partum. Milk yield and milk constituents were determined weekly. The degree of udder evacuation was determined by the succeeding removal of residual milk. PC released OT during the milking process, whereas in WC no OT release was detected throughout the milking process. Consequently, the residual milk fraction was much lower in PC than in WC (11% v. 58%, P<0.05) and daily milk yield until day 91 post partum was higher in PC than in WC (12.6+/-0.3 v. 7.1+/-0.4 kg, P<0.05). In conclusion, Syrian Shami cattle are not suitable to be exclusively machine milked without the presence of their calves.

Failure of captopril to prevent nitrate tolerance in congestive heart failure secondary to coronary artery disease.

The possible role of angiotensin-converting enzyme inhibition in preventing or minimizing tolerance to intravenous nitroglycerin in severe congestive heart failure (CHF) was studied by quantitating the degree of tolerance in 12 patients receiving nitroglycerin (group 1) and in 9 patients (group 2) receiving nitroglycerin and concurrent treatment with captopril (60 +/- 29 mg/day). At peak effect, nitroglycerin produced almost identical hemodynamic changes in both groups, with significant decreases in right atrial and pulmonary arterial wedge pressure, systolic blood pressure and systemic and pulmonary vascular resistances. Cardiac index increased. The extent of nitrate tolerance was calculated for each hemodynamic parameter as the percentage loss of the peak effect achieved by the drug. At 24 hours, 98 +/- 80% of the benefit achieved with respect to right atrial pressure was lost in group 1 and 61 +/- 74% in group 2 (group 1 vs 2, difference not significant). For pulmonary arterial wedge pressure, 51 +/- 31% (group 1) and 85 +/- 53% (group 2) (difference not significant) of the effect was lost, and for cardiac index, 53 +/- 58% (group 1) and 54 +/- 44% (group 2) (difference not significant). Tolerance was also almost identical regarding systolic blood pressure and systemic and pulmonary vascular resistance. Thus, the extent of tolerance to high-dose intravenous nitroglycerin in CHF was unaltered by administration of captopril, indicating that in clinical dosage, counter-regulatory neurohumoral mechanisms involving the renin-angiotensin system appear to be unimportant in its development.

[Percutaneous transluminal coronary angioplasty after coronary artery bypass].

Anginal syndrome may recur early of several years after coronary artery bypass surgery (CABS), and may be due to narrowing of a bypass graft, progression of pre-existing coronary artery lesions, or the appearance of new lesions. Repeat CABS is associated with considerable morbidity and mortality. We therefore performed percutaneous transluminal angioplasty (PTCA) in saphenous or internal mammary bypass grafts or native coronary arteries in 23 patients after CABS. We successfully dilated 35 of 37 lesions (95%) present in 33 of 35 vessels (94%) of 21 of 23 patients (91%). The mean vessel narrowing decreased from 86 +/- 22% to 13 +/- 19% (p less than 0.001) and in all 21 patients with angiographic evidence of success functional capacity improved. Single vein grafts were successfully dilated in 9 patients. None developed acute myocardial infarction or needed emergency surgery, but 1 had a cerebral embolism. PTCA is effective therapy for recurrent angina after CABS, and in many patients is preferable to another operation.

Short- and long-term results of angioplasty for multiple coronary stenoses.

Sixty-eight patients underwent percutaneous transluminal coronary angioplasty (PTCA) for multiple coronary stenoses. Lesions involved one coronary vessel in 24 patients, two in 34, and three or more vessels in 10 patients. The primary patient success rate was 96%, and we successfully dilated 162 (91%) of 179 significant (i.e., greater than 70% obstructive) coronary lesions, mean 2.4 lesions/patient. Complete coronary revascularization was achieved in 24 patients (Group 1), while major narrowings were not dilated either by intention or due to failure of dilation in 42 others (Group 2). The clinical state of the patients improved markedly after successful PTCA, and 44 (72%) of 61 were in the New York Heart Association Functional Class I or II 3 to 24 months later. In keeping with the clinical results, there was a significant improvement in treadmill exercise performance, in both groups. Patients with complete revascularization, however, tended to exercise longer (NS) to a greater heart rate (P less than 0.004) with less or no ischemic ST depression on ECG (P less than 0.04). Complications were few and limited to patients undergoing PTCA for unstable angina pectoris or following acute myocardial infarction. One patient (1%) died, two (3%) had Q-wave infarction and one patient sustained a cerebral embolus during catheterization. Restenosis was observed in 6 (29%) of 21 consecutive patients recatheterized 6 to 12 months (or sooner for symptoms) after successful PTCA. Four patients underwent a repeat PTCA, one was referred for coronary artery bypass grafting (CABG), and in one restenosis was minor and symptoms were mild. PTCA should be considered in patients with multiple coronary stenoses in whom all or most of the significant lesions can be dilated. Partial revascularization by PTCA is clinically useful and may be preferable to CABG in patients in whom the surgical risk is increased.