POSTNATAL DEVELOPMENT OF RENAL FUNCTION IN PRE-TERM AND FULL-TERM INFANTS

ABSTRACT. Aperia, A., Broberger, B., Klinder, G., Herin, P. and Zetterström, R. (Department of Paediatrics, Karolinska Institute, St. Göran's Children's Hospital, Stockholm and Huddinge Hospital, Huddinge, Sweden). Postnatal deveopment of renal function in preterm and full-term infants. Acta Paediatr Scand, 70:183, 1981. –This study has been designed to examine the effect of gestational age (GA) on the postnatal development of renal function and has been performed in pre-term (PT) infants (GA=30–34 weeks) and in full-term (FT) infants (GA=39–41 weeks). Postnatal age has ranged from 1–35 days. From 8 hour urine samples collected after spontaneous voiding and a capillary blood sample, determinations have been made of the clearance of creatinine (C_Cr), the fractional excretion of β₂-microglobulin (FE_β2) and the fractional excretion of sodium (FE_Na). In some infants receiving fluid parenterally, simultaneous determinations were made of the clearance of creatinine and inulin. As judged from this study, C_Cr is a reliable indicator of the glomerular filtration rate (GFR). GFR was almost the same in newborn PT and FT, but from 0.3–1 week of age GFR increased significantly more rapidly in FT than in PT. From 1–5 weeks of age GFR increased at approximately the same rate in PT and FT infants. The absolute value for GFR in 3–5 weeks old infants was lower in PT than in FT. FE_β2 was higher in PT than in FT infants during the entire first month of life and FE_Na was higher in PT than in FT infants during the first week of life, suggesting a glomerular tubular imbalance at least at the level of the proximal tubule in PT infants. It is concluded that different stages of maturation will alter the preconditions for the renal adaptation to extrauterine life during at least the first month of life. Therefore special attention must be paid to the limited renal function in PT during their entire first month of life.     

Diverticular complications of renal failure

Ten patients with chronic renal failure presented with complications of colonic diverticula. Five had acute diverticulitis, 4 perforated diverticula, and 1 lower gastrointestinal hemorrhage. Symptoms were less severe than expected. In 3 the diagnosis was first suspected when free intra-abdominal air was detected. Seven patients had laparotomy, 5 emergently. Radiologists should be aware of the potential for diverticular complication in patients with renal failure, even with minimal or absent symptoms. Suspicion of colonic pathology either clinically or radiographically should be evaluated promptly so that aggressive therapy can begin.     

Beneficial effects of coronary venous retroinfusion of superoxide dismutase and catalase on reperfusion arrhythmias, myocardial function, and infarct size in dogs

The efficacy of coronary venous retroinfusion of superoxide dismutase and catalase was studied in anesthetized closed chest dogs with 90-min left anterior descending coronary artery (LAD) occlusion followed by 3-h reperfusion. In group A, superoxide dismutase (2.5 mg/kg) and catalase (2.5 mg/kg) were administered by a 30-min continuous right atrial infusion beginning 15 min before reperfusion and supplemented by a bolus injection of superoxide dismutase (2.5 mg/kg) and catalase (2.5 mg/kg) through the great cardiac vein immediately before reperfusion. The treatment in group B was similar to that in group A, except that the bolus injection was into the right atrium. In the control group (group C), saline was administered in the same manner as in group A. Infarct size, expressed as a percentage of the risk area, was significantly smaller in group A (11.3 +/- 8.9%) than in groups B (31.3 +/- 21.1%) and C (43.0 +/- 16.9%; p less than 0.05). Regional function of the ischemic zone measured by two-dimensional echocardiography exhibited significantly (p less than 0.05) greater recovery after 3-h reperfusion in group A (30.3 +/- 8.4%) versus groups B (12.5 +/- 13.7%) and C (12.1 +/- 11.7%). Moreover, there were significantly fewer postreperfusion ventricular arrhythmias in group A as compared with groups B and C. The results of this study indicate that coronary venous retroinfusion is an effective method for delivery of superoxide dismutase and catalase.     

Oral bioavailability and pharmacokinetics of PAT-5A, a new insulin sensitizer in rats.

Pharmacokinetics of PAT-5A (a new thiazolidinedione derivative), a potent insulin sensitizing and lipid-lowering compound was studied in rats. A single dose of 3, 10, 30 and 100 mg/kg PAT-5A was given orally to Wistar rats for investigating the dose linearity in pharmacokinetics. In another study, a single intravenous bolus dose of PAT-5A was given to rats at 10 mg/kg dose following administration through the tail vein in order to obtain the absolute oral bioavailability and clearance parameters. Blood samples were drawn at predetermined intervals and concentration of PAT-5A in plasma was determined by a validated HPLC method. Plasma concentration versus time data was generated following oral and i.v. dosing and subjected to noncompartment pharmacokinetic analysis to obtain the values for the parameters. Both Cmax and AUC0-infinity appeared to increase proportionally to the administered oral doses. While the doses increased in the ratio of 1.0:3.3:10.0:33.3, the mean Cmax and AUC0-infinity increased in the ratio of 1.0:3.3:8.0:16.7 and 1:4.4:12.0:32.1, respectively. The systemic clearance and volume of distribution of PAT-5A in rats were 83.1 mL/h and 177.1 mL respectively after i.v. administration. Plasma concentrations declined monoexponentially following oral as well as intravenous administration and terminal half-life was about 1.4 h. There was no significant change in half-life with increase in oral doses. Absolute oral bioavailability of PAT-5A across the doses tested was in the range of 73-100% and this indicates that PAT-5A is neither a candidate for pre-systemic metabolism nor prone to absorption-related issues.     

Prostatic evaluation by transrectal sonography with histopathologic correlation: the echopenic appearance of early carcinoma

Fifty-two patients with clinical stage A and B carcinomas of the prostate were imaged by ultrasound (US) transrectally with a 5-MHz linear array transducer and transabdominally with a 3-MHz sector scanner prior to radical prostatectomy. The fresh specimens of 44 prostate glands were scanned in a water bath with a 5-MHz linear array transducer in multiple planes. In all cases, histopathologic correlation was obtained. Prostatic carcinoma presented as an echopenic lesion in 54% of the specimens, as a slightly hypoechoic area in 22%, and could not be identified in 24% because of its isoechoic characteristics. In contrast to many previous reports, no instance of echogenic cancer was observed.     

Tuberculosis in long-term-care facilities.

The geriatric population represents the largest reservoir of Mycobacterium tuberculosis infection in developed nations, including the United States. Tuberculosis (TB) case rates in the United States are highest for this age group compared with other age categories. The subtle clinical manifestations of TB in the elderly often can pose potential diagnostic dilemmas and therapeutic challenges, resulting in increased morbidity and mortality in this age group; this treatable infection unfortunately often is detected only at autopsy. Compared with their community-dwelling counterparts, the institutionalized elderly are at a greater risk both for reactivation of latent TB and for the acquisition of new TB infection. Prevention and control of TB in facilities providing long-term care to the elderly thus cannot be overemphasized.     

Particulate matter,air pollution,and blood pressure

A short-term increase in fine particulate matter air pollution (PM_2.5) concentration increases the risk for myocardial infarctions, strokes, and heart failure exacerbations. An important mechanism likely contributing to these associations is an elevation in arterial blood pressure (BP). Exposure to ambient PM_2.5 even at present-day concentrations can increase BP within a period of a few days while long-term exposure might also promote the development of chronic hypertension. Controlled human and animal experiments have corroborated the veracity of these findings and elucidated plausible biological mechanisms. PM_2.5 deposition within the pulmonary tree is capable of rapidly triggering autonomic nervous system imbalance, thereby increasing BP within minutes of inhalation. In addition, fine particles can instigate a systemic pro-inflammatory response over a more prolonged period of exposure. Higher circulating levels of activated immune cells and inflammatory cytokines could consequently cause vascular endothelial dysfunction leading to an imbalance in vascular homeostatic responses. Indeed, chronic PM_2.5 exposure augments pro-vasoconstrictive pathways while blunting vasodilator capacity. Finally, certain particle constituents (e.g., metals, organic compounds, and ultra-fine particles) might also be capable of reaching the systemic circulation upon inhalation and thereafter directly impair vascular function. At the molecular level, the generation of oxidative stress with the consequent up-regulation of redox sensitive pathways appears to be a common and fundamental mechanism involved in the instigation of these pro-hypertensive responses. Due to the ubiquitous, continuous and often involuntary nature of exposure, PM_2.5 may be an important and under-appreciated worldwide environmental risk factor for increased arterial BP.     

Decision analysis computer program for use in the labor room

A decision analytic model (a decision tree) was constructed for use in the labor room. Probabilities and (dis)utilities were estimated by obstetricians and computerized. A sensitivity analysis on six branches of the decision tree uses estimates of four obstetricians and proves that the decisions resulting from the model are stable and insensitive to differences in probability estimates within reasonable limits. Therefore it is concluded that we can construct a decision tree that is a practical, valuable, and stable tool for consistent decision making.