Carbonic anhydrase II and IV mRNA in rabbit nephron segments: stimulation during metabolic acidosis.

Carbonic anhydrase (CA) facilitates renal bicarbonate reabsorption and acid excretion. Cytosolic CA II catalyzes the buffering of intracellular hydroxyl ions by CO2, whereas membrane-bound CA IV catalyzes the dehydration of carbonic acid generated from the secretion of protons. Although CA II and IV are expressed in rabbit kidney, it is not entirely clear which segments express which isoforms.

Regulation of surfactant proteins A and B by TNF-alpha and phorbol ester independent of NF-kappa B.

Acute lung inflammation is complicated by altered pulmonary surfactant phospholipid and protein composition. The proinflammatory cytokine tumor necrosis factor-alpha (TNF-alpha) and the phorbol ester 12-O-tetradecanoyl phorbol-13-acetate (TPA) inhibit expression of surfactant-associated proteins A and B (SP-A and SP-B), both important for normal surfactant function. The transcription factor nuclear factor-kappa B (NF-kappa B) frequently mediates regulation of gene expression by TPA and TNF-alpha.

Ventricular-vascular uncoupling by acute conotruncal occlusion in the stage 21 chick embryo.

Embryonic ventricular diastolic and systolic function was evaluated during normal ejection (coupled) and during acute ventricular outflow tract occlusion (uncoupled) in the stage 21 chick embryo. We simultaneously measured ventricular pressure with a servo-null system and ventricular dimensions using video microscopy. Experimental protocols included 1) baseline recording followed by acute conotruncal (CT) ligation (n = 15) and 2) baseline recording, preload increase using Krebs-Henseleit buffer (3 microliters), preload reduction via venous hemorrhage, and then CT occlusion (n = 20).

Developmental changes in flow-wave propagation velocity in embryonic chick vascular system.

We analyzed flow-wave propagation velocity in the early embryonic vascular system and its responses to acute alterations in circulating blood volume. Two 20-MHz pulsed Doppler velocimeters were positioned along the arterial system in stage 18 (n = 12), 21 (n = 10), and 24 (n = 11) chick embryos. Distance between the two measurement sites was measured by video-microscopy.

Hyperoxic injury decreases alveolar epithelial cell expression of vascular endothelial growth factor (VEGF) in neonatal rabbit lung.

Normal neonatal lung growth requires a substantial increase in microvascular endothelial cells. Oxygen injury to neonatal lung destroys endothelial cells and alters the normal process of alveolarization, including development of the microvasculature. The mechanisms that regulate lung alveolar capillary growth and development are not known.

Changes in surfactant protein gene expression in a neonatal rabbit model of hyperoxia-induced fibrosis.

Lung injuries, including bronchopulmonary dysplasia, alter the surfactant system. We developed a newborn rabbit model of acute, followed by chronic, hyperoxic injury to study surfactant protein (SP) gene expression. Initial litters were exposed to >95% O2 until 50% died (LD50; 7-11 days old).

Outcome for patients with bulimia and breast hypertrophy after reduction mammaplasty.

Objectives: To determine the outcome of patients with bulimia nervosa and symptomatic breast hypertrophy (macromastia) who had reduction mammaplasty and to identify factors that were associated with positive outcomes.

Design: Case series with semistructured, retrospective, personal interviews performed an average of 4 years after the procedure.

Setting: University hospital-based adolescent eating disorder program.

Expression of fibronectin mRNA splice variants by rabbit lung in vivo and by alveolar type II cells in vitro.

Fibronectin (FN) is a multidomain glycoprotein with putative functions in tissue development and repair. In repair of alveolar injury, FN may promote the transition of type II epithelial cells to type I epithelial cells. Alternative splicing of FN mRNA, including the EIIIA and EIIIB exons, results in protein isoforms that have cell, tissue, and developmental specificity.

Strain-induced growth of the immature lung.

To investigate the relationship between strain and postnatal lung growth, two groups of weanling ferrets were tracheotomized: the study group was exposed for 2 wk to a continuous positive airway pressure (CPAP) of 6 cmH2O and the other group was exposed to atmospheric pressure (control). Total lung capacity after 2 wk was approximately 40% higher in the CPAP-exposed animals than in the control animals (n = 19 for the control group and 18 for the study group; P < 0.01).

Linearity of pulsatile pressure-flow relations in the embryonic chick vascular system.

The calculation and modeling of vascular input impedance are based on the assumption that pressure and flow are linearly related in the frequency domain. However, this assumption has not been proven for the embryonic circulation. Therefore, we investigated the linearity of pulsatile pressure flow relations in vivo with acute alterations in cycle length.

Nitroprusside selectively reduces ventricular preload in the stage 21 chick embryo.

Objective: Embryonic cardiovascular function is dynamically regulated at the tissue level. Nitric oxide (NO) regulates vascular tone and influences cardiovascular function in neonatal and mature circulations. However, the role of NO in regulating embryonic cardiovascular function is undefined.

Distribution of blood flow between embryo and vitelline bed in the stage 18, 21 and 24 chick embryo.

Objective: We defined the distribution of blood flow between the embryo and the extraembryonic vascular bed as an initial step in understanding the control of flow distribution in the early developing heart.

Methods: Dorsal aortic blood flow of stage 18, 21, and 24 chick embryo (n > or = 7 at each stage) was measured with a 20 MHz pulsed-Doppler velocity meter. Analog waveforms were digitally sampled at 500 Hz.

Interleukin-8 and monocyte chemoattractant protein-1 mRNAs in oxygen-injured rabbit lung.

The chemokines interleukin-8 (IL-8) and monocyte chemoattractant protein-1 (MCP-1) are neutrophil and monocyte attractants, respectively. We hypothesized that IL-8 and MCP-1 mRNA expression in alveolar macrophages (AM) lavaged from rabbit lung would be increased by oxygen exposure, which is known to induce inflammation. Adult rabbits were exposed to > 95% oxygen for up to 64 h and allowed to recover in room air for up to 72 h before killing and pulmonary lavage.

Transforming growth factor-beta 1 modulates type II cell fibronectin and surfactant protein C expression.

Extracellular matrix (ECM) deposition by alveolar type II cells is important for repair of a damaged alveolar epithelium. Transforming growth factor-beta (TGF-beta) is abundant in injured lung and has profound effects on ECM production and cell differentiation. We determined the effects of TGF-beta 1 on type II cell expression of fibronectin and surfactant protein C (SP-C) in vitro.

Tyrosine kinase activity is necessary for growth factor-stimulated rabbit type II pneumocyte proliferation.

Tyrosine kinases are important in the signal transduction of a number of growth factors. As shown previously, transforming growth factor (TGF)-alpha stimulated proliferation of type II cells in vitro. The mitogenic effect of TGF-alpha could be blocked by the addition of the tyrosine kinase inhibitors genistein or tyrphostin.

Transforming growth factor-beta induces a chondroitin sulfate/dermatan sulfate proteoglycan in alveolar type II cells.

Alveolar type II cells can synthesize extracellular matrix (ECM) components in vitro, including proteoglycans. Transforming growth factor-beta (TGF-beta) profoundly influences ECM production and is found in areas of lung fibrosis. To determine whether type II cell proteoglycan synthesis is regulated by TGF-beta, we cultured adult rabbit type II cells with TGF-beta 1 and analyzed the synthesis of proteoglycans secreted into the culture medium.

Insulin-like growth factor-I induces cyclin-D1 expression in MG63 human osteosarcoma cells in vitro.

The insulin-like growth factors (IGFs) stimulate cell division by modulating events occurring during the prereplicative (G1) phase of the cell cycle, but identification of the critical events has proved difficult. Recent observations suggest that progression through the cell cycle is dependent on the activation of a group of serine-threonine-specific protein kinases whose activities are regulated by accessory proteins, termed cyclins. The identification of cyclin species expressed during G1 has led to the hypothesis that modulation of cyclin expression may be the critical event regulated by growth factors.

Human kidney proximal tubules are the main source of plasma glutathione peroxidase.

The sites of synthesis of extracellular (E) glutathione peroxidase (GPX), a unique selenoglycoprotein present in plasma, are not known. To investigate the possibility that the kidney is the main source for the plasma GPX, we examined GPX activities and selenium concentrations in the plasma of patients with renal failure on dialysis and nephrectomized patients before and after kidney transplantation. Plasma GPX activities in these patients were 42, 22, and 180% of normal EGPX activity, respectively, whereas plasma Se levels were within the normal range.

Increased expression of tissue inhibitor of metalloproteinases (TIMP-I) and metallothionein in murine lungs after hyperoxic exposure.

Acute exposure to hyperoxia results in well-described pathophysiologic responses in the lungs, beginning with subtle, subcellular changes and ending with severe pulmonary inflammation and edema. The biologic events that underlie or accompany this injury are not well understood. Our previous studies in rabbits have shown that hyperoxia induces large increases in the mRNAs encoding metallothionein (MT) and the tissue inhibitor of metalloproteinases (TIMP-I).

Growth factors alter neonatal type II alveolar epithelial cell proliferation.

The type II alveolar epithelial cell plays a critical role in the repair of lung injury by repopulating the entire damaged alveolar epithelium. We report our studies of the effects of known growth factors on the in vitro proliferation of isolated neonatal rabbit type II cells. Transforming growth factor-alpha (TGF-alpha) and epidermal growth factor (EGF) increased [3H]thymidine incorporation, cell number, and labeling index above control.

Comparative pharmacokinetic studies of three asparaginase preparations.

Purpose: As part of pharmacologic studies of asparaginase (ASNase), we determined the half-life of ASNase activity and protein, and the effect of dose, repeated doses, different drug preparations, and hypersensitivity reactions on the half-life (t1/2) of serum ASNase activity.

Patients And Methods: We measured ASNase activity (spectrophotometric assay) in serum samples obtained from patients with acute lymphoblastic leukemia (ALL) at various times during their therapy with intramuscular ASNase. ASNase protein was measured by enzyme-linked immunoadsorbent assay (ELISA).

Meconium aspiration syndrome: physiological and inflammatory changes in a newborn piglet model.

In order to evaluate further the physiological and inflammatory changes of meconium aspiration syndrome (MAS), 25 newborn piglets (1-2 days old, 1.5 +/- 0.4 kg) were studied.

Effect of IL-1 on experimental bone/bone-marrow metastases.

Bone metastasis is a common event and a major cause of morbidity in cancer patients. The hematopoietic marrow of the bones, rather than the bone tissue per se, is the target organ in bone metastasis. In the bone marrow, IL-1 induces the release of hematopoietic growth factors that may affect tumor-cell growth.

Cellular and molecular responses to lung injury in relation to induction of tissue repair and fibrosis.

Those factors that determine whether tissue injury is followed by regeneration and repair or irreversible destruction and fibrosis are only now being elucidated. This article examines the lung's response to injury, the prominent role of polypeptide growth factors and cytokines in directing tissue responses, and the effects of injury on cell-specific expression of a number of genes.

Alveolar type II cells synthesize hydrophobic cell-associated proteoglycans with multiple core proteins.

Type II alveolar epithelial cells interact with the extracellular matrix via cell surface receptors for matrix ligands. Cell surface proteoglycans, which are hydrophobic due to their membrane insertion domains, are one of several classes of molecules that may be receptors for matrix ligands. To analyze the hydrophobic proteoglycans synthesized by adult alveolar type II cells, we labeled these cells with 35SO4 and [3H]leucine in short-term primary cultures.