To examine possible racial differences in the relationship between urinary sodium excretion (UNaV) and blood pressure in whites and blacks, and to characterize cardiovascular, renal and humoral responses, we studied 14 normotensive men (seven white and seven black) at six levels of sodium intake from 10-1500 mEq/24 hrs. Systolic and diastolic pressure increased from 113 ± 2/69 ± 2 mm Hg (SEM) at the 10 mEq/24 hr level of sodium intake to 131 ± 4/85 ± 3 mm Hg at the 1500 mEq/24 hr level of sodium intake (p < 0.001). Cardiac index increased concomitantly from 2.6 ± 0.1 to 3.6 ± 0.3 I/min/M2 (p < 0.001). Linear and quadratic regression analysis of the relationship of UNaV and blood pressure revealed that blacks had higher blood pressures with sodium loading than whites. Sodium loading caused a significant kaliuresis that was greater in whites than blacks. Six subjects were restudied while receiving potassium replacement. Compared with initial responses, blood pressure was elevated to a lesser degree (p < 0.02) and a greater natriuresis appeared at a level of 1500 mEq/24 hr of sodium intake (p < 0.02). The data suggest that blacks have an intrinsic reduction in the ability to excrete sodium compared with whites. The increases in blood pressure with acute sodium loading can be attributed to an increase in cardiac index. Potassium balance appears to influence the responses in blood pressure that occur with sodium loading.

Open surgery for removal of upper urinary tract stones has long been associated with a high morbidity and mortality. So when shock wave (SW) lithotripsy (SWL) was introduced in the early 1980s, the climate was right for acceptance of a noninvasive method for stone comminution. The growth in popularity of SWL was extremely rapid, based in part on the perception that it was entirely safe [1]. Now, after a decade of clinical SWL, experience tells us differently. SWL may be very effective at breaking kidney stones, but it can also cause severe renal trauma that can lead to irreversible long-term complications [2, 3].

Both the dorsomedial hypothalamic nucleus (DMH) and the paraventricular hypothalamic nucleus (PVN) have been implicated in the neural control of the cardiovascular response to stress. We used the GABAA agonist muscimol to inhibit neuronal activation and attempted to identify hypothalamic nuclei required for the cardiovascular response to air stress. Chronically instrumented rats received bilateral injections of either 80 pmol of muscimol or 100 nl of saline vehicle into the DMH, the PVN, or an intermediate area (including the rostral edge of the DMH and the region between the two nuclei) and were placed immediately in a restraining tube and subjected to 20 min of air stress. In all rats, air stress after vehicle injections caused marked increases in heart rate (137 +/- 6 beats/min) and blood pressure (26 +/- 2 mmHg). Microinjection of muscimol into the DMH suppressed the heart rate and blood pressure response by 85 and 68%, respectively. Identical microinjection of muscimol into the intermediate area between the DMH and the PVN attenuated the increases in heart rate by only 46% and in blood pressure by 52%. In contrast, similar injections into the vicinity of the PVN failed to alter the cardiovascular response to air stress. These findings demonstrate that muscimol-induced inhibition of neuronal activity in the region of the DMH blocks air stress-induced increases in heart rate and arterial pressure, whereas similar treatment in the area of the PVN has no effect.

This article considers the recent trends in the palm oil market balance and the future prospects for palm oil fundamentals. The article finds that there exists potential for the demand for palm oil and its products to increase quite steeply, partly due to emerging demand as a relatively cheap biofuel (whether as palm biodiesel or for direct burning), and partly due to its price advantages in edible applications. In terms of supply, as long as there is willingness to plant more area with oil palm in environmentally sensitive areas, there will be continued growth in the oil palm industry. This development is likely to be led primarily by Indonesia with increasing areas planted with oil palm, notably in Kalimantan, and by continued yield improvements in Malaysia.

Lithotripsy shock waves (SW) to one renal pole damage that pole but protect the opposite pole from the damage inflicted by another, immediate application of SW. This study investigated whether the protection (1) occurs when the first treatment causes no injury, (2) is caused by SW or injury, (3) exhibits a threshold, and (4) occurs when the same pole receives both treatments. Six-to 7-wk-old anesthetized female pigs were studied. The following groups were studied: group 1 (n ‫؍‬ 4), 2000 SW at 12 kV to one pole and 2000 SW at 24 kV (standard) to the opposite pole; group 2 (n ‫؍‬ 6), same as group 1 except 500 12-kV SW pretreatment; group 3 (n ‫؍‬ 8), 500 12-kV, 2000 standard SW, all to the same pole; and group 4 (n ‫؍‬ 8), same as group 3 except 100 12-kV SW pretreatment. Mean ؎ SD lesion size in group 1, first pole treated, was 0.66 ؎ 0.82% of functional renal volume (FRV; P < 0.05 versus 5.22 ؎ 3.6% FRV with no pretreatment [NP]; 95% confidence interval [CI] ؊7.0 to ؊2.1) and 0.50 ؎ 0.68% FRV in the opposite pole after 2000 standard SW (P < 0.05 versus NP; 95% CI ؊9.4 to ؊0.08). Mean lesion size (first pole) in group 2 was 0.020 ؎ 0.028% FRV (P < 0.01 versus NP; 95% CI ؊9.2 to ؊1.2) and 0.43 ؎ 0.54% FRV in the opposite pole after 2000 standard SW (P < 0.05 versus NP; 95% CI ؊8.8 to ؊0.82). Same-pole SW (groups 3 and 4) also protected. Mean lesion sizes were 0.28 ؎ 0.33% (P < 0.01 versus NP; 95% CI ؊8.0 to ؊1.9) in group 3 and 0.39 ؎ 0.48% FRV (P < 0.01 versus NP; 95% CI ؊8.2 to ؊1.7) in group 4. It is concluded that the pretreatment protocol substantially limits the renal injury that normally is caused by SWL and occurs when the pretreatment and standard SW are applied to the same pole. The threshold for the protection may be <100 SW.