Biomedical subjects

C L Wagner

Publications and source records attributed to C L Wagner.

36 records · Page 2Linked to original sources

PubMed1996

Chromatin reorganization in rat spermatids during the disappearance of testis-specific histone, H1t, and the appearance of transition proteins TP1 and TP2.

Transition proteins replace testis-specific histones and are finally replaced by protamines in the nucleus of germ cells during spermiogenesis. In this study, immunoperoxidase and immunogold localization were used to determine both qualitatively and quantitatively the intracellular distribution of testis-specific histone (H1t), transition protein 1(TP1), and transition protein 2 (TP2) during rat spermatogenesis. H1t labeling was concentrated over heterochromatin in the nucleus of late-pachytene spermatocytes and spermatids up to mid-steps 10. In step 9 spermatids, H1t was confined to the caudal end of the nucleus where heterochromatin was still present, while in early step 10 spermatids, only a few of the nuclei remained caudally labeled. In late step 10 spermatids, a fibrillar chromatin network was distributed throughout the nucleus coincident with the loss of H1t. A statistically significant rise in TP1 and TP2 labeling density over control values was first encountered in the nucleus of step 11 spermatids coincident with the initiation of condensation of the fibrillar chromatin. The TP1 and TP2 labeling density progressively increased in nucleus of step 11-13 spermatids with the apical to caudal condensation of the fibrillar chromatin, In step 13 spermatids, the chromatin was homogeneously condensed throughout the nucleus. In the case of TP1, the nuclear labeling density gradually declined after step 13 and disappeared by step 17. In the case of TP2, the nuclear labeling density disappeared by step 16. This study shows that, coincident with the loss of H1t, the chromatin of the spermatid is reorganized into a fibrillar network, whereas, coincident with the appearance and progressive increase of TP1 and TP2, the fibrillar chromatin condenses in an apical to caudal direction in the nucleus of the spermatid. Thus the remodeling of chromatin structure during spermiogenesis appears to be a two-step process that is sequentially influenced by the loss of spermatid-specific histones and the appearance of transition proteins.

Animals↗

PubMed1996

Special properties of human milk.

In this review, several nutritional and nonnutritive differences between mothers' milk and formula and their relationship to neonatal gastrointestinal and immune processes are discussed. The dynamic relationship of human milk as evidenced by its changing composition, unique bioactive and immunologic properties, and specialized cellular components is further delineated. The clinical significance and relevance of these findings to the clinician are then presented. Lastly, educational strategies, their effectiveness in promoting breastfeeding, and an approach that might be taken by the clinician to encourage breastfeeding are outlined.

Breast Feeding↗

PubMed1995

Comparative neonatal morbidity of abdominal and vaginal deliveries after uncomplicated pregnancies.

OBJECTIVE: To determine whether the risk of cesarean section following uncomplicated pregnancies has been reduced by current obstetric practices by comparing the neonatal risk of vaginal deliveries with the risk incurred following abdominal delivery in otherwise uncomplicated pregnancies. DESIGN: Observational, cohort study. A subpopulation of 11,702 women without complications of pregnancy was identified from a perinatal database, classified by subsequent mode of delivery, and compared for neonatal morbidity. This analysis was repeated after the cesarean section group was further narrowed to include only "repeated elective" deliveries. SETTING: Low-risk inborn setting. Tertiary care (level III nursery) referral center and a community (level II nursery) hospital. INTERVENTION: Cesarean section performed electively, for cephalopelvic disproportion, or for failure to progress. OUTCOME VARIABLES: Chosen prior to data analysis: neonatal mortality and morbidity. RESULTS: Groups differed with regard to ethnicity and sex. Infants who were delivered by cesarean section were more likely to have 1-minute Apgar scores less than 4, require intermediate or intensive nursery care at admission (6.3% vs 1.3% [P < .001]), and require greater respiratory support (mechanical ventilation, 1.6% vs 0.3%; oxygen therapy, 4.9% vs 1.4%; or room air, 93.5% vs 98.4% [P < .001]) than infants who were delivered vaginally. Similar results were found when patients who were delivered vaginally and by repeated elective cesarean section were compared. CONCLUSION: Although reports have recently emerged suggesting otherwise, abdominal delivery following an uncomplicated pregnancy remains a risk factor for adverse neonatal outcome despite current obstetric practices.

Apgar Score↗

PubMed1995

Variation in the biochemical forms of transforming growth factor-alpha present in human milk and secreted by human milk macrophages.

OBJECTIVE: Transforming growth factor-alpha (TGF-alpha), present in human milk, is thought to play a significant role in postnatal gut development. Macrophages, which abound in human milk, are known to secrete various isoforms of TGF-alpha in other areas of the body. It was hypothesized that human milk macrophages (HMM) secrete TGF-alpha, and HMM are a source of TGF-alpha isoforms present in human milk. We sought to measure in vitro HMM TGF-alpha secretion, and to compare the TGF-alpha isoform(s) present in human milk with those secreted by HMM. STUDY DESIGN: Colostrum and mature milk samples, obtained from mothers (n = 48) on postpartum days 3-30, were centrifuged. HMM were isolated, placed in culture for 24 h, and cell-free media collected. The biochemical forms of TGF-alpha in media in human milk supernatant samples were identified by Western blot analysis under reducing conditions. The concentration of the mature (6-kD) TGF-alpha isoform in those samples was quantified using a radioimmunoassay. RESULTS: Western blot analysis under reducing conditions identified a single 6-kD TGF-alpha isoform in all human milk supernatant samples tested, but variable (6- and 30- to 46-kD) TGF-alpha isoforms in HMM media. The mean (+/- SE) concentration of the 6-kD TGF-alpha isoform found in human milk supernatants was 706 +/- 88 pg/ml and 17.6 +/- 2.6 pg/ml in HMM media. CONCLUSION: These experiments show that HMM secrete TGF-alpha in biochemical forms both similar to and distinct from that found in human milk supernatant.

Blotting, Western↗

PubMed1995

Secretion of transforming growth factor-alpha (TGF alpha) by postnatal rabbit alveolar macrophages.

Transforming growth factor-alpha (TGF alpha) is a cytokine secreted by stimulated alveolar macrophages (AM) in vitro and after in vivo particulate or hyperoxia exposure and has been implicated in the processes of postnatal lung development. It is unknown if AM TGF alpha secretion changes during normal postnatal lung development. After sacrifice of New Zealand white rabbits on postnatal d 0-2, 5-7, 9-10, 14, 21, and 28 and > 4 mo (adult), AM were isolated by discontinuous density centrifugation and placed in culture in the presence or absence of concanavalin A (ConA) for 24 h. Media were collected, and the concentration and isoforms of TGF alpha in AM media samples were determined by an epidermal growth factor/TGF alpha radioreceptor assay and Western immunodetection, respectively. TGF alpha was present in media of AM from the 1.06 and 1.08 g/dL Percoll densities, but not in the 1.10 g/dL density. Statistically significant differences in TGF alpha secretion by unstimulated and ConA-stimulated AM at the various ages were not detected until d 14 (p < 0.02). Western blot analysis of unstimulated AM media samples from d 0-7 rabbits demonstrated the presence of TGF alpha isoforms at 46, 30, and 14.3 kD. At later postnatal ages (> or = d 9), a single 14.3-kD isoform was present. In contrast, analysis of ConA-stimulated AM media samples showed TGF alpha isoforms at 46, 30, and 14.3 kD for all ages; however, the 6-kD mature isoform was present only in juvenile (d 28) and adult media.(ABSTRACT TRUNCATED AT 250 WORDS)

Aging↗

PubMed1995

School-age follow-up of a single-dose prophylactic surfactant cohort.

This study reports the school-age developmental and health status of a preventilatory surfactant cohort. The sample consisted of 39 surviving subjects (21 experimental and 18 controls) born at 25 to 29 weeks gestation who were studied at 6 and 12 months and 5 to 7 years of age. At 6- and 12-month follow-ups, the cohort was functioning close to the population normative mean. Although cognitive and motor assessments at school age also showed no group differences, 8 of 19 (42%) in the surfactant group and 9 of 17 (53%) in the normal saline group attained a McCarthy General Cognitive Index score of < or = 84 (abnormal range). On the Connors' Parental Questionnaire, both groups scored high on the Learning Disability Subscale. The surviving cohort at 5 to 7 years had no identified long-term sequelae due to surfactant therapy, yet both groups were at risk for neurodevelopmental and educational morbidity.

Birth Weight↗

PubMed1994

Feeding premature infants while low umbilical artery catheters are in place: a prospective, randomized trial.

OBJECTIVE: The objective of this prospective, randomized clinical trial was to test the hypothesis that there is no difference in the frequency of feeding problems and necrotizing enterocolitis between a group of premature infants who received early enteral feedings while low umbilical artery catheters (LUACs) were in place, and a late group who were not fed until 24 hours after removal of LUACs. PATIENTS AND METHODS: Twenty-nine premature infants (born at 28.5 +/- 3.0 SD weeks of gestational age) who were in stable condition received early enteral feedings at a median of 2 days while a LUAC was in place; 31 infants (born at 28.6 +/- 2.7 SD weeks of gestational age) received late enteral feedings at a median of 5 days of age, 24 hours after the removal of the LUAC. Feeding complications and interventions and nutritional characteristics were recorded prospectively. RESULTS: There were no differences in the baseline perinatal characteristics of the two groups. The incidence of gastric residua and the incidence of abdominal distention were the same in both groups. The early feeding group had significantly fewer percutaneous central venous catheters, evaluations for sepsis, and episodes of receiving nothing by mouth while a gastric suction tube was in place. Infants in the early group received parenteral alimentation-lipid emulsion infusions for a median of 13 days versus 30 days for the late-fed group (p = 0.0028 by Wilcoxon test). There were two cases of necrotizing enterocolitis in the early group versus four cases in the late group. CONCLUSIONS: Premature infants in stable condition who receive enteral feedings while LUACs are in place do not have an increased incidence of feeding problems compared with infants who do not receive enteral feedings until 24 hours after removal of LUACs.

Catheterization, Peripheral↗

PubMed1994

Meconium analysis for improved identification of infants exposed to cocaine in utero.

We screened anonymously all mothers and infants born during a 3 1/2-month period to determine the prevalence of intrapartum cocaine use, test the maternal characteristics that are specific predictors of intrauterine cocaine exposure (IUCE), and compare the sensitivity of infant urine versus meconium samples for identification of IUCE. Of 1237 live births during the study period, a sample was obtained from 1201 mother-infant pairs. The overall prevalence of documented intrapartum cocaine exposure was 66 (5.5%) of 1201 pairs. Previously developed drug screening guidelines had a sensitivity of 89% for detecting IUCE in infants. Direct comparisons of samples from the same mother-infant pair revealed that there were no cases in which cocaine was found in infant urine but not in meconium; however, infant urine testing missed 25% of the infants who had positive findings in meconium. We conclude that (1) meconium testing was more likely than urine testing to identify an infant with IUCE, detecting an additional 33%; (2) there was significant maternal cocaine use (5.5%) in a teaching hospital with a mixed patient population; (3) maternal characteristics known to identify infants at risk of having IUCE were useful in our population; and (4) IUCE of neonates admitted to the neonatal intensive care unit was more common than that of infants admitted to the regular newborn nursery.

Cannabis↗

PubMed1994

The "88% saturation test": a simple lung function test for young children.

OBJECTIVE: The 88% saturation test (88%-SAT) was developed as an alternative to standard spirometry for those young children unable to perform standard forced expiratory maneuvers. In adults, this test revealed rapid desaturation in those persons with a history of asthma when compared with healthy control subjects. Similar findings in children were tested. SETTING: Tertiary care hospital. PATIENTS: Thirty-three former premature infants (28.3 +/- 2.3 weeks gestation), aged 5 to 7 years, who were participating in a follow-up study, were enrolled in this study. DESIGN: The study compared the 88%-SAT with standard spirometry and respiratory health characteristics ascertained through a parental questionnaire. The 88%-SAT consists of continuous measurement of hemoglobin saturation by pulse oximetry (SaO2) while the subject breathes a nonhumidified 12% oxygen and nitrogen mixture for 10 minutes or until SaO2 decreases to 88%, whichever occurs first. Abnormal 88%-SAT was defined as a decrease of SaO2 to 88% within the 10-minute period, and abnormal spirometry was defined using standardized values. RESULTS: Of the 20 children who successfully completed both spirometry and the 88%-SAT, 10 had normal spirometry results and did not desaturate to 88%, and 5 had abnormal spirometry and 88%-SAT results. Four children did not desaturate during the 88%-SAT, but had abnormal spirometry results, and one child had abnormal 88%-SAT results, but normal spirometry. Ten additional children completed the 88%-SAT, but not standard spirometry. Three children were unable to complete either test. Of those 30 children tested, 7 (23%) had a history of reactive airways disease, and all 7 had abnormal 88%-SAT results. The 88%-SAT had greater sensitivity (100% vs 75%) and specificity (87% vs 63%) than spirometry in identifying children with known reactive airways disease. The mean McCarthy general cognitive index (GCI) of the group performing both spirometry and the 88%-SAT (n = 20) achieved a mean (+/- SD) GCI of 96.2 +/- 16.7, and the group (n = 30) that completed the 88%-SAT had a mean (+/- SD) GCI of 75.2 +/- 26.3 (chi 2 P < .012). The 10 children able to perform only the 88%-SAT had a mean GCI (+/- SD) of 72.8 +/- 26.9, and the 3 children unable to perform either test had a mean GCI (+/- SD) of 63 +/- 11. CONCLUSIONS: Our data suggest that the 88%-SAT may be more effective than spirometry for identifying reactive airways disease in young, uncooperative, or developmentally delayed children. The dry air of the hypoxic inspired gas may function as an airway challenge, leading to decreased oxygenation in patients with reactive airways.

Child↗

PubMed1987

Analysis of the major large polypeptides of rat seminal vesicle secretion: SVS I, II, and III.

Rat seminal vesicle secretion (SVS) contains a variety of protein complexes that seem to be linked by interchain disulfide bonds. Upon reduction and analysis by sodium dodecyl sulfate (SDS) gel electrophoresis, this pattern resolves to 3 major high molecular weight (SVS I-100,000, SVS II-50,000, SVS III-37,000) and 3 major low molecular weight protein bands (SVS IV, V, and VI). A two-dimensional SDS gel (1st dimension unreduced, 2nd dimension reduced) permitted identification of the components of the cross-linked species. In the native secretion, SVS I forms a series of oligomers that include both SVS II and III. Essentially all of SVS III is involved in these complexes, while the bulk of SVS II occurs instead as an apparent homodimer. The smaller proteins (SVS IV-VI) are not involved in covalently crosslinked complexes. The reduced forms of the larger polypeptides were isolated by a variety of procedures involving agarose gel filtration in 6M guanidine hydrochloride, reversed-phase high pressure liquid chromatography, ammonium sulfate fractionation, and preparative polyacrylamide gel electrophoresis. Based on its size, solubility, and amino acid composition, SVS II was identified as the major clottable protein of the secretion.

Amino Acids↗

PubMed1975

An alternative to routine operative cholangiography.

The use of the Fogarty biliary balloon catheter has added to the safety of common duct exploration. Review of our own series seems to support this concept. With this adjunct adn a careful anatomic dissection of the biliary system, one can decide to do cholangiography or common duct exploration based on carefully considered clinical factors when stones are suspected. Perhaps neither need to be done in many instances. Without trying to question the virtures of operative cholangiography, we believe that it can be used selectively rather than routinely.

Catheterization↗

PubMed1969