The Iowa Perinatal Letter, October-November-December 2007, Vol. 28, no. 4

This newsletter from The Department of Public Health about perinatal health care and statistics.

The Iowa Perinatal Letter, January-February-March 2008, Vol. 29, no. 1

This newsletter from The Department of Public Health about perinatal health care and statistics.

The Iowa Perinatal Letter, April-May-June 2008, Vol. 29, no. 2

This newsletter from The Department of Public Health about perinatal health care and statistics.

The Iowa Perinatal Letter, July-August-September 2008, Vol. 29, no. 3

This newsletter from The Department of Public Health about perinatal health care and statistics.

The Iowa Perinatal Letter, October-November-December 2008, Vol. 29, no. 4

This newsletter from The Department of Public Health about perinatal health care and statistics.

The Iowa Perinatal Letter, January-February-March 2009, Vol. 30, no. 1

This newsletter from The Department of Public Health about perinatal health care and statistics.

The Iowa Perinatal Letter, April-May-June 2009, Vol. 30, no. 2

This newsletter from The Department of Public Health about perinatal health care and statistics.

The Iowa Perinatal Letter, July-August-September 2009, Vol. 30, no. 3

This newsletter from The Department of Public Health about perinatal health care and statistics.

The Iowa Perinatal Letter, October-November-December 2009, Vol. 30, no. 4

This newsletter from The Department of Public Health about perinatal health care and statistics.

The Iowa Perinatal Letter, January-February-March 2010, Vol. 31, no. 1

This newsletter from The Department of Public Health about perinatal health care and statistics.

The Iowa Perinatal Letter, April-May-June 2010, Vol. 31, no. 2

This newsletter from The Department of Public Health about perinatal health care and statistics.

Circadian and circaseptan patterns of natality and perinatal mortality of infants with different birth weights

OBJECTIVE. Data on human natality, stillbirth and perinatal mortality from Switzerland (1979-1987), available in four birthweight categories, are reexamined to assess any about-weekly (circaseptan) and changes in about-daily (circadian) patterns in central Europe over a century and a halfDESIGN. Retrospective analyses on archived data.SETTING. Federal Office of Statistics for Switzerland.RESULTS. In addition to prominent circadians, weekly patterns are also documented.CONCLUSION. Exogenous variations, prominent in early extrauterine life, such as changes of scheduling in obstetrics, may contribute to circadian and cireaseptan natality patterns. Information on these patterns serves in the optimization of neonatal care. Partly endogenous, partly physical environmental aspects, at least of about-weekly patterns, remain to be elucidated in series consisting exclusively of spontaneous parturitions.

The Iowa Perinatal Letter, July, August, September 2010, Vol. 31, no. 3

This newsletter from The Department of Public Health about perinatal health care and statistics.

Studies of the renal effects of angiotensin II receptor blockade: the confounding factor of acute water loading on the action of vasoactive systems.

The acute renal tubular effects of two pharmacologically distinct angiotensin II receptor antagonists have been evaluated in normotensive volunteers on various salt diets. In the first study, the renal response to a single oral dose of losartan (100 mg) was assessed in subjects on a low (50 mmol Na/d) and on a high (200 mmol Na/d) salt intake. In a second protocol, the renal effects of 50 mg irbesartan were investigated in subjects receiving a 100 mmol Na/d diet. Both angiotensin II antagonists induced a significant increase in urinary sodium excretion. With losartan, a modest, transient increase in urinary potassium and a significant increase in uric acid excretion were found. In contrast, no change in potassium and uric acid excretions were observed with irbesartan, suggesting that the effects of losartan on potassium and uric acid are due to the intrinsic pharmacologic properties of losartan rather than to the specific blockade of renal angiotensin II receptors. Assessment of segmental sodium reabsorption using lithium as a marker of proximal tubular reabsorption demonstrated a decreased distal reabsorption of sodium with both antagonists. A direct proximal tubular natriuretic effect of the angiotensin II antagonist could be demonstrated only with irbesartan. This apparent discrepancy allowed us to reveal the importance of acute water loading as a possible confounding factor in renal studies. The results of the present analysis show that acute water loading per se may enhance renal sodium excretion and hence modify the level of activity of the renin-angiotensin system expected from a given sodium diet. Since acute water loading is a common practice in clinical renal studies, this confounding factor should be taken into account when investigating the renal effects of vasoactive systems.

Short-term and sustained renal effects of angiotensin II receptor blockade in healthy subjects.

We investigated the short-term and sustained hormonal and renal effects of angiotensin II (Ang II) receptor blockade in normotensive healthy volunteers. Twenty-four subjects maintained on a fixed sodium diet were randomized to receive for 8 days a placebo or 10 or 50 mg doses of the Ang II antagonist irbesartan (SR 47436, BMS 186295) according to a double-blind, parallel group design. Plasma renin activity, plasma immunoreactive Ang II and aldosterone levels, blood pressure, renal hemodynamics, and urinary electrolyte excretion were measured for 8 hours after the first and eighth administration of each dose of irbesartan or placebo. Ang II receptor blockade with irbesartan induced a dose-dependent compensatory increase in plasma renin activity and plasma angiotensin levels and a significant decrease in plasma aldosterone levels. The compensatory rise in plasma renin activity and Ang II levels was more pronounced on day 8, reflecting a long duration of the blocking effect of irbesartan. Irbesartan induced small changes in blood pressure and did not significantly modify renal blood flow and glomerular filtration rate. However, a significant decrease in filtration fraction was observed during receptor blockade on days 1 and 8. The tubular effects of irbesartan were characterized by a dose-dependent increase in sodium and chloride excretions. Interestingly, the cumulative natriuretic response to Ang II receptor blockade was similar on days 1 and 8, suggesting that in these subjects, renal Ang II receptors are not blocked over 24 hours during repeated administration even though this antagonist has a long duration of action (t1/2 of 15 to 17 hours).(ABSTRACT TRUNCATED AT 250 WORDS)