Evaluating the impact of CPAP weaning procedures on total days on nasal CPAP: A retrospective chart review.

BACKGROUND: There is no consensus on how to wean infants from Nasal Continuous Positive Airway Pressure (NCPAP). We hypothesized that ceasing NCPAP abruptly would decrease the duration required, compared with a gradual wean. METHODS: This retrospective chart review included preterm infants requiring NCPAP for over 48 hours. Cohort1 weaned NCPAP by cycling on and off, while cohort 2 ceased NCPAP abruptly. The primary outcome was total days on NCPAP. Secondary outcomes included rate of bronchopulmonary dysplasia, weight gain, duration of hospital stay, and compliance with the use of stability criteria. RESULTS: 81 infants met inclusion criteria in cohort one, and 89 in cohort two. Median days on NCPAP were 17.0 and 11.0 days, respectively, not significant. There was no significant difference in secondary outcomes. CONCLUSIONS: There was no significant association between the two NCPAP weaning protocols and the outcomes studied.

Chitotriosidase and gene therapy for fungal infections.

Chitotriosidase secreted by activated human macrophages has been implicated in the defence against chitin-bearing pathogens. The antifungal properties of human chitotriosidase were investigated here following retroviral vector-mediated gene transfer of the open reading frame of the chitotriosidase gene into Chinese hamster ovary cells. A chitinase assay confirmed that the engineered cells secreted recombinant chitotriosidase constitutively. Two dimensional gel electrophoresis and western blotting indicated that the recombinant protein is the major, chitin-binding, fifty kilodalton isoform. Culture medium conditioned by the transduced cells inhibited growth of isolates of Aspergillus niger, Candida albicans and Cryptococcus neoformans. Furthermore, longevity was significantly increased in a mouse model of cryptococcosis when cells transduced with the chitotriosidase gene and encapsulated in alginate microspheres were implanted subcutaneously in the animals. Engraftment of microcapsules containing cells transduced with the chitotriosidase gene has the potential to combat infections caused by chitinous pathogens through the prolonged delivery of recombinant chitotriosidase.

RNA synthesis in the mouse oocyte.

RNA synthesis in the oocyte and granulosa cell nuclei of growing follicles has been studied in the mouse ovary. The RNA precursor [(3)H]uridine was administered intraperitoneally to adult mice and the amount of label incorporated into ovarian RNA was quantitated autoradiographically using grain-counting procedures. Uridine incorporation into the nucleus is low in oocytes of small, resting follicles but increases during follicle growth and reaches a peak prior to the beginning of antrum formation. Thereafter uptake rapidly declines and is very low in the oocytes of maturing follicles. Uridine incorporation into granulosa cell nuclei, in contrast to that found in the oocyte, increases gradually during most of the period of follicle growth. Qualitative studies of the activity of endogenous, DNA-dependent RNA polymerases have also been made in fixed oocytes isolated from follicles at different stages of growth. Polymerase activity is demonstrable in the nucleolus and nucleoplasm of oocytes from growing follicles, but is absent from maturing oocytes of large follicles.

Evolutionary conservation of repetitive sequence expression in sea urchin egg RNA's.

Cloned repetitive DNA sequences were used to determine the number of homologous RNA transcripts in the eggs of two sea urchin species, Strongylocentrotus purpuratus and S. franciscanus. The eggs of these species contain different amounts of RNA, and their genomes contain different numbers of copies of the cloned repeats. The specific pattern of repetitive sequence representation in the two egg RNA's is nonetheless quantitatively similar. The evolutionary conservation of this pattern suggests the functional importance of repeat sequence expression.

Worsening anemia associated with volvulus in a stable neonate with intestinal obstruction.

Intrauterine intestinal obstruction complicated by midgut volvulus is a serious life-threatening diagnosis. Immediate surgical intervention is generally the course of action upon diagnosis to prevent morbidity and mortality. We report a case of intrauterine intestinal obstruction where the neonate then presented with an unusual onset of volvulus within the first 12 hours of life. The patient was born with generalized edema, a distended abdomen, and pallor. Unlike many cases, the patient did not present with typical signs of volvulus. Diagnostic imaging preceding delivery and the stable postnatal clinical course did not offer a justification for immediate laparotomy. Less than 24 hours later, the patient's hemoglobin significantly dropped leading to an emergent laparotomy. Findings included a volvulus of the terminal ileum and large amounts of intraluminal blood. Our case report includes an analysis of clinical observations that should be considered so that patients presenting with similar signs receive earlier surgical intervention.

Organization and evolution of the actin gene family in sea urchins.

Genomic libraries of the sea urchins Strongylocentrotus franciscanus and Lytechinus pictus were screened with an actin cDNA clone from Strongylocentrotus purpuratus. Four nonoverlapping clones were isolated and characterized from the S. franciscanus library; three were isolated and characterized from the L. pictus library. Linked genes having the same transcriptional orientation were found on all S. franciscanus clones. Three clones contained two actin genes each; the other clone contained three. In contrast, the L. pictus clones contained only one actin gene. Comparison of actin genomic clones from these three species indicated a difference in the genomic organization of sea urchin actin genes in that the genes appear to be more highly clustered in S. franciscanus than in S. purpuratus and L. pictus. Genomic dot blots and reassociation kinetics demonstrated that the copy number of actin genes in all three species is 15 to 20. Nucleotide sequence homology of actin genes within and among the species was measured by thermal elution. These experiments indicated that there is a high degree of interspecies actin gene sequence homology but that, within each species, actin gene sequences may differ by as much as 30%. Sequencing of two S. franciscanus actin genes revealed introns at the same amino acid positions, 121 and 204, reported for S. purpuratus actin genes. These data demonstrated that the genomic copy number, the transcriptional orientation of linked genes, and, to the extent studied, the intron position of actin genes have evolved similarly in these three species. In contrast, significant change has occurred in the chromosomal arrangement of sea urchin actin genes.

Field testing of decision coaching with a decision aid for parents facing extreme prematurity.

OBJECTIVE: The objective of this study is to assess and modify an existing decision aid and field-test decision coaching with the modified aid during consultations with parents facing potential delivery at 23 to 24 weeks gestation. STUDY DESIGN: International Patient Decision Aid Standards instrument (IPDASi) scoring deficits, multi-stakeholder group feedback and α-testing guided modifications. Feasibility/acceptability were assessed. The Decisional Conflict Scale was used to measure participants' decisional conflict before (T1) and immediately after (T2) the consultation. RESULTS: IPDASi assessment of the existing aid (score 11/35) indicated it required updated data, more information and a palliative care description. Following modification, IPDASi score increased to 26/35. Twenty subjects (12 pregnancies) participated in field-testing; 15 completed all questionnaires. Most participants (89%) would definitely recommend this form of consultation. Decisional conflict scores decreased (P<0.001) between T1 (52±25) and T2 (10±16). CONCLUSION: Field testing demonstrated that consultations using the aid with decision coaching were feasible, reduced decisional conflict and may facilitate shared decision-making.

Tumor-specific genetically engineered murine/human chimeric monoclonal antibody.

Murine variable and human constant region exons were fused to produce "chimeric" immunoglobulin gamma and kappa genes. These constructs were cotransfected into murine myeloma cells which then produced and secreted intact, functional antibody. Cells secreting the chimeric antibody were introduced into mice. The engineered immunoglobulin was subsequently harvested from ascites fluid and was purified by affinity chromatography. Its immunological properties were compared to those of the parental murine monoclonal (B6.2), which exhibits specificity for human breast, lung, and colon carcinoma cells. Competitive binding, immunofluorescent cell staining, and analysis of immunoprecipitated antigen gave similar results for the chimeric and murine B6.2. The biodistribution of chimeric and murine B6.2 after injection into mice bearing human tumors was found to be identical. These results suggest that murine/human chimeric antibodies may be viable clinical replacements for murine monoclonals with the potential for better immunological tolerance and pharmacological efficacy.

Shared decision making for infants born at the threshold of viability: a prognosis-based guideline.

OBJECTIVE: Making prenatal decisions regarding resuscitation of extremely premature infants, based on gestational age alone is inadequate. We developed a prognosis-based guideline. STUDY DESIGN: We followed a five step approach and used the AGREE II framework: (1) systematic review and critical appraisal of published guidelines; (2) identification of key medical factors for decision making; (3) systematic reviews; (4) creation of a multi-disciplinary working group and (5) external consultation and appraisal. RESULT: No published guideline met high-quality appraisal criteria. Survival, neurodevelopmental disability, quality of life of child and parents, and maternal mortality and risk of long-term morbidity were identified as key for quality decision-making. Eighteen stakeholders (including parents) advocated for the incorporation of parents' values and preferences in the process. CONCLUSION: A novel framework, based on prognosis, was generated to guide when early intensive and palliative care may both be offered to expectant parents. Pre-implementation assessment is underway to identify barriers and facilitators to putting in practice.

The characterization of multiple forms of kynurenine formidase in Drosophila melanogaster.

Two enzymic forms of kynurenine formamidase (EC 3.5.1.9) from Drosophila melanogaster were separated and partially purified by pH fractionation, (NH4) 2SO4 fractionation and Sephadex G-75 gel filtration. The enzymes were also separated by DEAE-cellulose ion-exchange chromatography and distinguished by their different rates of thermal inactivation. The multiple forms are termed formamidase I and formamidase II. The molecular weight of formamidase I as measured by Sephadex G-75 chromatography is 60 000 and that of formamidase II is 31 000. The pH optima are broad, ranging between 6.7 and 7.8 for formamidase I and 6.5 and 8.0 for formamidase II. The apparent Km values are 5-10(-3) and 0.83-10(-3) M, resepctively. The possibility that formamidase II is an active subunit of formamidase I is discussed, although neither enzyme will convert to the other when separated and rechromatographed. Eight organisms were tested for the presence or absence of multiple forms of formamidase. Drosophila melanogaster and Drosophila virilis have both enzymes; cow, chicken, yeast and housefly have formamidase I only, and mouse and frog have formamidase II only.

Characterization of five members of the actin gene family in the sea urchin.

Hybridization of an actin cDNA clone (pSA38) to restriction enzyme digests of Strongylocentrotus purpuratus DNA indicates that the sea urchin genome contains at least five different actin genes. A sea urchin genomic clone library was screened for recombinants which hydridize to pSA38 and four genomic clones were isolated. Restriction maps were generated which indicate that three of these recombinants contain different actin genes, and that the fourth may be an allele to one of these. The restriction maps suggest that one clone contains two linked actin genes. This fact, which was confirmed by heteroduplex analysis, indicates that the actin gene family may be clustered. The linked genes are oriented in the same direction and spaced about 8.0 kilobases apart. In heteroduplexes between genomic clones two intervening sequences were seen. Significant homology is confined to the actin coding region and does not include any flanking sequence. Southern blot analysis reveals that repetitive DNA sequences are found in the region of the actin genes.

Construction, expression and characterization of a murine/human chimeric antibody with specificity for hepatitis B surface antigen.

A murine/human chimeric antibody with specificity for Hepatitis B surface antigen has been produced by genetic engineering. The light and heavy chain variable region exons encoding the murine monoclonal antibody 2H1 were isolated and inserted into mammalian expression vectors containing the human kappa and gamma 1 constant region exons. The chimeric genes were transfected into murine Sp2/0 hybridoma cells by electroporation and transfectomas secreting chimeric antibody were isolated. Secretion levels ranged from 1-7 pg/cell/24 hr. The chimeric antibody bound specifically to Hepatitis B surface antigen and competed effectively with the parental murine monoclonal antibody for binding to these sites. Chimeric 2H1 is the first clinically relevant, genetically engineered anti-viral antibody and may represent an improved agent for the prevention of hepatitis B virus transmission.

Localization of epidermal growth factor immunoreactivity in sheep skin during wool follicle development.

Interactions among the cells and matrices of the epidermis and mesenchyme of skin are essential for hair follicle initiation and development. The identification of receptors for epidermal growth factor (EGF) on epithelial components of the follicle during growth has suggested that the ligand participates in some of these events. We have used affinity-purified antibodies together with an alkaline phosphatase detection procedure to investigate the distribution of EGF in the skin of the sheep during wool follicle formation. Immunoreactivity was restricted to the periderm and intermediate layers of fetal epidermis at 55 d of gestation, when the first wave of wool follicles are initiated. This particular distribution persisted during subsequent development but never became associated with the basal cells of the epidermis. The activity was lost around 118 d, coinciding with sloughing of the periderm. No immunoreactivity was found in the plugs or the dermal condensations of the developing follicles. At approximately 105 d of gestation, however, reactions were detected in the outer root sheath as the follicles matured and in the differentiating cells of the sebaceous glands. A similar distribution pattern was also noted at 140 d, just prior to birth, and in adult animals, indicating that EGF was sequestered and perhaps synthesized within the follicle. The presence of immunoreactive material was also associated with the pilary canals and the skin surface, suggesting that this may have had its origin in the sebaceous glands. We examined this using a radioreceptor assay for EGF. Material washed from the skin surface and sebaceous gland extracts were found to displace 125I-EGF from rat liver membranes, in parallel with mouse EGF.

Epidermal hyperplasia and wool follicle regression in sheep infused with epidermal growth factor.

The proliferative activities of germinative cells of the wool follicles and the epidermis have been determined in sheep treated with epidermal growth factor (EGF). Infusions of 0.17-0.72 mg EGF/kg metabolic body weight (MBW) for 28 h resulted in marked declines in the mitotic indices (MI) of the follicle bulb cell populations 24 h after the beginning of treatment, the lowest values being recorded at 48 h. Follicular activity subsequently recovered and the MI returned to preinfusion levels after 3-8 days. The inhibition of fiber production resulting from the decline in bulb cell division caused the development of a break in the fleece. By contrast, the MI of the peripheral cells of the sebaceous gland acini and the basal cells of the epidermis increased after EGF treatment, reaching peaks 48-72 h after the beginning of infusion. The degree to which all of these responses were observed appeared to be approximately correlated with the amount of EGF administered.

Changes in the proteins of wool following treatment of sheep with epidermal growth factor.

Administration of epidermal growth factor (EGF) extracted from mouse submaxillary gland to Merino sheep resulted in a temporary inhibition of the activity of the wool follicles. Subsequently, either complete discontinuities appeared in the fibers resulting in shedding of the entire fleece, or incomplete, in which case the fleece was retained but bore a zone of weakness. The protein composition of the first sample of wool harvested from 1 sheep following infusion for 66 hr with 27.5 mg EGF (0-2 weeks posttreatment) was similar to pretreatment wool. This represented wool fibers which were already present in the follicles at the beginning of infusion. Thereafter, the composition of the wool changed progressively, reaching a maximum divergence from the control in the 3-4 week regrowth period followed by a return to normal by about 10 weeks. Over this period the content of high-sulfur proteins first rose from an initial 19% to a maximum of 30%, then returned to 19%, while the high-tyrosine protein content initially decreased from 12% to 5% and then slowly increased to 12%. In addition to changes in overall protein composition, two-dimensional electrophoresis revealed alterations in the proportions of some individual protein components. These changes were similar to those observed with many other wool growth inhibitors. Smaller doses of EGF (5.8 and 2.9 mg but not 1 mg) had similar effects on wool composition but these were of lower magnitude and there was a delay in reaching a maximum response. Even after 16-18 weeks the wool from these treated sheep differed slightly in composition from the pretreatment samples.

Epidermal growth factor causes hypocalcemia in sheep.

During iv infusions of epidermal growth factor into sheep, serum calcium concentrations fell, whereas serum magnesium and serum immunoreactive PTH levels increased. Urinary calcium and magnesium decreased significantly. The role of epidermal growth factor in calcium homeostasis is discussed.

Epidermal growth factor alters milk composition and fluid balance of lactating ewes.

Lactating ewes were treated with murine epidermal growth factor (EGF) and its effects on concomitant milk production and composition were observed. Six ewes were infused via the jugular vein with 200 ml saline/day over 4 days (days 9-12 of lactation) followed by EGF at a dose rate of 0.5 mg/day in 200 ml saline over 4 days (days 13-16). All ewes then received a further infusion of 200 ml saline/day over 4 days (days 17-20). During the experiment a maintenance (lactation) diet was offered and ewes were machine-milked twice daily. An EGF-immunoreactive material was detected in mammary secretions and urine throughout the experiment, but only in plasma (1-9 micrograms/l) during the period of EGF infusion. The amount of EGF appearing in milk and urine increased from 37 micrograms and 10 micrograms respectively (day 1 of EGF infusion) to 56 micrograms and 17 micrograms respectively (day 4). EGF treatment resulted in lower milk yield and reduced concentration of lactose and protein; milk fat concentration fell after EGF infusion had ceased. Water intake increased markedly during EGF infusion and was 60% (4 kg) greater on day 4 than that measured during the first saline infusion. Urine volume also increased and was 164% (3.6 kg) greater by day 4 of EGF infusion compared with that recorded in the first saline infusion. Water retention (intake minus output in milk, urine and faeces) was significantly higher on the day after EGF infusion ceased than that found during the first saline infusion. The possibilities that the increased water intake was primary, or secondary, to a diuretic effect of EGF are discussed.

Effects of epidermal growth factor on hair growth in the mouse.

The growth of the first hair coat in male mice was studied during administration of epidermal growth factor (EGF). Injections of 1 or 4 micrograms EGF/g body weight for 14 consecutive days from birth resulted in the development of curved overhairs (monotrichs), caused a retardation in rate of growth in length of hair and a reduction in hair diameter and length of follicle bulb. Growth rate partially recovered after cessation of EGF treatment. However, some of the effects produced by injections of EGF during the formation of the first coat were detected in the second and third generations of hair. Since EGF also retarded rate of body growth, we compared the effect of EGF on hair growth with that of restricting food intake in neonatal mice during the development of the first coat. Hair growth was slowed in underfed animals but the effects were less marked than those found in EGF-treated mice of similar body weights.

Fluid balance, electrolyte profiles and plasma parathyroid hormone concentrations in ewes treated with epidermal growth factor.

The infusion of low doses of epidermal growth factor (EGF) into lactating ewes stimulates water intake and urine volume. The plasma concentrations and daily output of various electrolytes in milk and urine are also affected. We have investigated this further by recording the effects of EGF infusion on fluid balance, electrolyte profiles and plasma concentrations of glucose and parathyroid hormone (PTH) in non-pregnant, non-lactating ewes. Twenty-four animals (n = 8 per group) received infusions of 100 ml saline/day into the jugular vein for 10 days (days 1-10) followed by EGF at a dose rate of either 1 (low dose), 5 (medium dose) or 10 (high dose) micrograms/kg liveweight per day in 100 ml saline for 5 days (days 11-15). All ewes then received an infusion of 100 ml saline/day for 10 days (days 16-25). Most plasma and urine samples had undetectable concentrations of EGF-immunoreactive material during the periods of saline infusion. During EGF infusion, the highest amounts of EGF infusate excreted in urine were 1.6, 5.9 and 5.6% for ewes in low, medium and high dose groups respectively. Water intake increased by 17% (0.5 kg), 88% (2.5 kg) and 89% (2.3 kg) and urine volume increased by 29% (0.5 kg), 108% (2.2 kg) and 134% (2.1 kg) for the three groups respectively. Fluid balance and feed intake were not affected by EGF infusion, but the output of faecal dry matter was reduced in ewes receiving the two higher doses of EGF. All levels of EGF resulted in hypocalcaemia, increased plasma PTH concentrations and hypermagnesaemia. There was no effect of EGF on plasma concentrations of K+ and glucose or on daily urinary excretion of K+ and Mg2+. The only response to the low dose was a reduced plasma concentration of Na+ and an increased daily urinary urate excretion. The two higher doses increased the daily urinary excretion of Na+, PO4(3-) and urate, but had no effect on the respective concentrations in plasma. Urinary Ca2+ excretion was reduced only during infusion of the medium dose of EGF. The responses of most variables were similar during infusion of the medium and high doses of EGF. All three doses of EGF induced polydipsic and diuretic responses in ewes, and infusions of 5-10 micrograms EGF/kg liveweight per day affected renal excretion of Ca2+, Na+ and PO4(3-). We interpret the responses of the kidney and plasma PTH concentrations as a means of maintaining the homeostasis of plasma profiles of electrolytes.

Inhibition of DNA synthesis in dermal tissue of merino sheep treated with depilatory doses of mouse epidermal growth factor.

Two groups of three Merino wethers were infused intravenously with either 0.12 mg mouse epidermal growth factor (mEGF)/kg fleece-free body weight or 0.9% (w/v) NaCl over 24 h. Sheep treated with mEGF rejected food during treatment but feed intake was kept equal for both groups. Wool growth and plasma concentrations of mEGF were measured during the experiment. Pieces of skin taken from the wool-growing regions of the body were incubated with radioactive thymidine in order to measure its rate of incorporation into DNA. The skin was then divided at about the level of the sebaceous glands into sections that contained the upper dermis and epidermis (E sections) and those containing the generative wool-follicle bulbs (D sections). No mEGF was detected in the controls whereas mean levels of about 35 micrograms mEGF/1 plasma were detected during the last 4 h of infusion in the protein-treated group. After infusion, wool growth was reduced by about 20% of the mean pretreatment level in the controls and no shedding of wool fibre was evident. In the mEGF-treated sheep, on the other hand, wool growth was depressed by 75-95% of the mean pretreatment level and the fleeces were almost completely cast in all three of the animals, leaving them nude on the wool-growing regions of the body. Wool growth was restored to its pretreatment level in this group about 1 month after infusion. The D sections of skin contributed 50-60% of skin wet weight in controls throughout the experiment.(ABSTRACT TRUNCATED AT 250 WORDS)