Elevated environmental lead levels in a day care setting.

OBJECTIVE: To determine the risk of lead poisoning among children enrolled in day care centers with elevated environmental lead burdens. DESIGN: Survey. SETTING: Six day care centers on properties owned by a major state-supported university. PATIENTS AND OTHER PARTICIPANTS: One hundred fifty-five of 234 eligible children (mean age, 4.8 years) enrolled in these centers were screened by questionnaire for risk factors of lead exposures. Blood samples for lead levels were also obtained. Observations of day care activities relative to lead exposure risks were recorded. Analyses of lead levels in paint, dust, and/or soil samples at the six centers were obtained. MAIN OUTCOME MEASURES: Prevalence of elevated blood lead levels and associated behavioral risk factors for lead exposure in children attending day care centers. RESULTS: Elevated levels of lead in paint (2.4% to 40% lead) were present in all day care facilities. Three day care centers had elevated lead levels in windowsill dust (62,000 to 180,000 micrograms [corrected] of lead per square meter) or soil (530 to 1100 mg of lead per kilogram): Questionnaires documented low risk for lead exposure to children in the home environments. Direct observations in the day care setting revealed optimal supervision and hygiene of the children. Blood lead levels were less than 0.5 mumol/L (10 micrograms/dL) in all but one of the 155 children screened. CONCLUSIONS: Children attending day care centers with high environmental lead burdens need further documentation of blood lead levels, at-risk behaviors, and lead exposure risks in the home environments as an adjunct to the instigation of lead abatement procedures at the day care centers.

Immune thrombocytopenia and elemental mercury poisoning.

Three cases of severe mercury toxicity occurring within a family are reported. Two cases of thrombocytopenia occurred in this family and represent the second such report in the literature of an association between elemental mercury toxicity and thrombocytopenia. Three of the children presented with a combination of dermatologic and neurologic manifestations reminiscent of acrodynia or pink disease. Each of the four children in this family were treated with dimercaptosuccinic acid. The hazard of vacuuming spilled mercury and appropriate clean-up procedures are described.

Cutaneous vasculitis in the newborn of a mother with cutaneous polyarteritis nodosa.

Vasculitis in an infant of a woman who had a long history of cutaneous polyarteritis nodosa is reported. During the neonatal period the child developed cutaneous vasculitis manifested by livedo reticularis, cutaneous nodules, and acral necrosis. The infant's vasculitis remitted by age 7 months. This is the third such report and strongly suggests the presence of a circulating factor that is capable of crossing the placenta and inducing cutaneous polyarteritis nodosa.

Fluid requirements in the preterm infant.

Fluid requirements in the newborn are related to net fluid expenditures, normal changes in body water composition, and the integrity of renal regulatory functions. A variety of clinical conditions and therapeutic modalities also have an important effect on fluid requirements. Fluid therapy must be individualized to meet the specific needs of the infant. Appropriate fluid therapy will facilitate physiologic changes of body water composition and decrease neonatal morbidity.

Renal hemodynamic responses to hypoxemia during development: relationships to circulating vasoactive substances.

Chronically catheterized fetal lambs (n = 11, gestational age 111-139 days) and neonatal lambs (n = 20, postnatal age 4-30 days) were studied to explore during development the relationship of renal hemodynamic responses during hypoxemia to plasma epinephrine concentration (E), plasma norepinephrine concentration (NE), plasma arginine vasopressin concentration (AVP), and plasma renin activity (PRA). A low oxygen gas mixture (11.1 +/- 0.1% O2) was administered for 30 min to the pregnant ewe or neonatal lamb to induce hypoxemia with maintenance of normal arterial pCO2 and pH. Arterial blood pressure was recorded continuously and renal blood flow (RBF) was determined by the radiolabeled microsphere technique. Moderate hypoxemia (pO2 16 +/- 2 torr and 33 +/- 6 torr in fetus and neonate, respectively) induced increases in E, NE (measured by radioenzymatic assay), and AVP (measured by radioimmunoassay) in both fetus and neonate. PRA (measured by radioimmunoassay) also increased in response to hypoxemia in neonatal lambs. The change in mean arterial pressure with hypoxemia (delta MAP) was significant in fetuses (delta MAP 8 +/- 14%, p less than 0.05) but not in lambs (delta MAP 1 +/- 10%, p greater than 0.5). Similarly, the change in renal blood flow with hypoxemia (delta RBF) was significant (delta RBF -51 +/- 24%, p less than 0.001) in fetuses but not in neonatal lambs (delta RBF -9 +/- 38%, p greater than 0.1). These results reflected a change in renal vascular resistance with hypoxemia (delta RVR) that was significant in fetal lambs (delta RVR 169 +/- 168%, p less than 0.01) but not in neonatal lambs (delta RVR 51 +/- 180%, p greater than 0.2).(ABSTRACT TRUNCATED AT 250 WORDS)

Renal and adrenal responses to converting-enzyme inhibition in fetal and newborn life.

The renal and adrenal responses to a continuous infusion of the angiotensin-converting enzyme (ACE) inhibitor captopril were studied in 27 chronically catheterized sheep fetuses (less than 120 days gestation, n = 15, and greater than 130 days gestation, n = 12; term being 145 days) and in 12 newborn lambs between 8 and 21 days of age. Total renal blood flow did not change during ACE inhibition. However, the renal vascular resistance decreased significantly in newborn lambs (-21.8 +/- 5.7%) and in fetuses greater than 130 days (-21.7 +/- 4.7%) but not in fetuses less than 120 days. A significant decrease in filtration fraction (-19.2 +/- 6.5%) was observed in newborn lambs. No changes in urinary kallikrein and prostaglandin excretion rate were observed during ACE inhibition in any group of animals. ACE inhibition produced similar declines in blood pressure in both groups of fetuses (-10.2 +/- 3% in fetuses less than 120 days and -9.5 +/- 4.6% in fetuses greater than 130 days) and in newborn lambs (-13.4 +/- 2.1%). The percent changes in plasma renin activity were similar in all groups of animals. However, a significant decline in plasma aldosterone concentration was observed only in newborn lambs (from 130 +/- 31 to 64 +/- 9 pg/ml). These results suggest that the renin-angiotensin system might have physiological significance during maturation, but that this role seems to be more important in near-term fetuses (greater than 130 days) and postnatally than early in gestation.

Developmental aspects of the renal kallikrein-like activity in fetal and newborn lambs.

The ontogeny of the renal kallikrein-like activity and the interrelationships between this enzyme and the renin-angiotensin-aldosterone and prostaglandin systems were studied in 43 chronically catheterized sheep fetuses between 104 and 142 days of gestation (term, 145 days) and in 8 chronically catheterized newborn lambs between 5 and 23 days of age. Urinary kallikrein (UKall) excretion rate expressed in absolute values (mEU/hr) or corrected for kidney weight (mEU X hr-1 X gKW-1) or glomerular filtration (mEU X hr-1 X ml GFR-1) increased significantly during fetal maturation and after birth. The rise in UKall during fetal and newborn life was not dependent on an increase in urinary flow rate (r = 0.06). The increase in fetal UKall (mEU X hr-1 X gKW-1) correlated closely with the rise in plasma aldosterone concentration for values above 35 pg/ml (r = 0.72, P less than 0.001). A significant negative correlation was found between UKall (mEU X hr-1 X gKW-1) and log of individual urinary sodium excretion values (r = -0.78, P less than 0.001). No correlation was found between UKall and urinary prostaglandins (PGE, PGF2 alpha) excretion during fetal and newborn life, but UKall correlated closely with the rise in renal blood flow during maturation (r = 0.87, P less than 0.001). The present data suggest that aldosterone is an important regulator of UKall release early during development. It is also suggested that conceptional age is an important factor which may modulate the renal sensitivity to aldosterone-stimulated UKall excretion.

Tissue oxygen delivery in lambs: effect of postnatal age and acute hypoxemia.

Organ tissue arterial oxygen delivery in relation to postnatal age and acute hypoxemia (arterial pO2 34 +/- 5 Torr for 30 min) was studied in chronically catheterized, non anesthetized lambs 2-38 days of age. Baseline tissue oxygen delivery to heart and skeletal muscle correlated significantly with postnatal age. Acute hypoxemia induced significantly decreased oxygen delivery to kidney, spleen, ileum, jejunum and skeletal muscle without significant relation to postnatal age. Hypoxemia also induced increased arterial oxygen capacity and hemoglobin concentration which correlated significantly with postnatal age. These results suggest that baseline organ tissue oxygen delivery and response to hypoxemia remain constant during early postnatal maturation. Furthermore, hypoxemia may induce an apparent shift of fluid from the intravascular compartment which is greater in older lambs.

Postnatal age-related renal responses to hypoxemia in lambs.

The role of normocapnic hypoxemia (arterial PO2 33 +/- 7 torr for 30 minutes) in asphyxial renal failure and its modification by maturation of renal function was studied in 50 chronically catheterized, unanesthetized lambs of 2-38 days postnatal age. Arterial pH and PCO2 did not change significantly in response to hypoxemia in these lambs. Normocapnic hypoxemia was associated with (1) significant percent increases in arterial serum osmolality (1.82 +/- 2.96%, P = 0.0001), arterial blood lactate concentration (1009 +/- 2092%, P = 0.0018), arterial blood hematocrit (6 +/- 12%, P = 0.0016), arterial hemoglobin concentration (4.6 +/- 6.5%, P = 0.0004), arterial plasma vasopressin (2370 +/- 3340%, P = 0.0001), arterial plasma renin activity (153 +/- 230%, P = 0.0001), arterial plasma aldosterone (91.3 +/- 143%, P = 0.0001), and fractional sodium excretion rate (120 +/- 240%, P = 0.007); and (2) significant percent decline in glomerular filtration rate (-22.6 +/- 32.6%, P = 0.0003). Several responses to hypoxemia correlated significantly with postnatal age, including (1) positive correlation of postnatal age with percent change in blood osmolality (r = 0.36, P = 0.010), hematocrit (r = 0.48, P = 0.0005), hemoglobin (r = 0.59, P = 0.0004), and lactate (r = 0.72, P = 0.0001), suggesting greater water movement from the intravascular compartment in response to hypoxemia in more mature lambs; and (2) positive correlation of postnatal age with change in urinary flow rate (r = 0.66, P = 0.0001), urinary sodium excretion rate (r = 0.65, P = 0.0001), and osmolar clearance rate (r = 0.60, P = 0.0002), suggesting a greater effect of hypoxemia on the renal tubules to decrease sodium reabsorption in more mature kidneys. Thus, normocapnic hypoxemia may play a role in asphyxial renal failure, and the immature kidney does not have increased susceptibility to this condition.