[Prone position favors motor development of infants]. / Buikligging gunstig voor motorische ontwikkeling van zuigelingen.

OBJECTIVE: To determine the motor development in infants sleeping in the supine position compared to infants sleeping in the prone position, and to compare the levels of motor development of infants playing only in the supine position and of infants playing in the prone position as well. DESIGN: Prospective blinded comparing study. SETTING: Department of Physical Therapy, Maasziekenhuis, Boxmeer, the Netherlands. METHODS: Various measuring instruments were used in the home environment to determine the levels of motor development at the age of 5 months of 21 healthy infants born at term selected from a group of 160 infants attending the infant welfare clinic. RESULTS: Infants sleeping in the prone position (n = 8) showed a higher motor development than infants sleeping in the supine position (n = 13). Infants playing in the prone and supine position (n = 5) had a higher motor development than infants who played exclusively in the supine position (n = 15). CONCLUSION: Sleeping and playing in the prone position was accompanied by a higher motor development in healthy mature-born infants at the age of 5 months.

Human and rat lung biotransformation of cyclosporin A and its derivatives using slices and bronchial epithelial cells.

Lung biotransformation of the immunosuppressants, cyclosporin A (CSA), the hydroxyethyl derivative SDZ IMM 125 (IMM), and the methylcarbonate derivative SDZ SCP 764 (SCP), was demonstrated in slices from human and rat. The major biotransformation pathway for CSA and IMM (0.1-10 microM) was hydroxylation at amino acid 1 to form AM1 or IMM1, while for SCP it was an esterase cleavage of the methylcarbonate group to form AM1 in both species. The initial rate (0-1 hr) of human total metabolite formation increased proportionally with substrate concentration. AM1 formation was five times greater from SCP, an esterase pathway, than CSA, an oxidative pathway which was inhibited (50%) by ketoconazole. At 24 hr human lung CSA metabolite formation was greater than IMM (3-fold) or SCP (2-fold), whereas rat lung and liver and human bronchial epithelial cell SCP metabolite formation generally exceeded CSA or IMM metabolism. CSA biotransformation is expected to occur throughout the human lung as demonstrated by the similar metabolite profile and extent of metabolism by slices derived from five different regions. The scaling of slice total metabolism to organ metabolism revealed that initially lung CSA metabolite formation would be equal to liver but with time liver metabolism would exceed lung for human and rat. This study has demonstrated that human and rat lung are metabolically active, exhibiting oxidative and esterase pathways toward cyclosporin derivatives. The lung will play an important role in this metabolism, particularly when administered via inhalation; however, the liver will also be a major organ involved in the total clearance of these compounds.

Nucleoside phosphatase activities on pig pancreas zymogen granule membranes analyzed by non-denaturing polyacrylamide gel electrophoresis.

The membrane of the pancreatic zymogen granule plays an important part in the sequence of storage, transport and exocytosis of digestive enzymes. While much is known on stimulus-secretion coupling, very little is understood about how the storage organelles move in the cytoplasm to the luminal plasma membrane and why and how they fuse with it to release the contents. It is assumed that nucleoside phosphatases are involved in these energy consuming processes. Pancreatic zymogen granule membranes contain one major glycoprotein, GP-2, and a few minor proteins all with unknown functions. In order to identify functions we have purified zymogen granule membranes from pig pancreas, solubilized the proteins under non-denaturing conditions with the detergent CHAPS and characterized the extracted proteins by polyacrylamide gel electrophoresis, histochemistry and lectins. Three major protein bands, often fused in one broad band, revealed enzymatic activity for adenosine-, cytidine-, inositol- and guanidine- di- and triphosphates by the precipitation of liberated phosphate by Pb(NO3)2. This activity was sensitive to known ATP diphosphohydrolase inhibitors. The band with activity arises from a 92 kDa glycoprotein. A different narrow band showed monophosphatase activity for AMP, GMP, IMP and CMP. Some of the activities were inhibited by different lectins, indicating glycosyl groups near the active site. Electron microscopical cytochemistry confirmed a nucleoside phosphatase activity on granule membranes. Our results show for the first time that the nucleoside phosphatase activity of the zymogen granule membranes is carried by a 92 kDa glycoprotein, probably the known self-associating form of GP-2. The hydrolysis of tri- and diphosphate nucleotides could provide the energy required by exocytosis.

Separation and analysis of pig pancreatic zymogen granules with free flow electrophoresis and lectins.

Purified pig pancreatic zymogen granules were subjected to free flow electrophoresis (FFE) in an acetate buffer system (acetic acid/NaOH, pH 5.5) to detect the presence or absence of more than one population or zymogen granules. Pig pancreatic zymogen granules were purified by differential and density gradient centrifugation and subjected to FFE. Fractions were analyzed for protein, alpha-amylase (EC 3.2.1.1) and 5'-nucleotidase (EC 3.1.3.5) as marker enzymes for zymogen granule content and membranes, respectively. Only one distinct peak, with coincident alpha-amylase and 5'-nucleotidase activity, and most protein was detected, which reflects the presence of a single population of intact zymogen granules. This was confirmed by electron microscopy. When the granules were incubated with different lectins before FFE, the one distinct peak representing intact zymogen granules was shifted towards the cathode in the case of concanavalin A (Con A) and Ricinus communis agglutinin 120 (RCA 120). No splitting of the peak occurred. Our results do not support the hypothesis of a coexistence of more than one distinct population of zymogen granules.