PubMed · 4705889
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U Haller. 1973-04-20. [Placenta insufficiency].. https://pubmed.ncbi.nlm.nih.gov/4705889/
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PURPOSE: Wound healing of the cryo-injured bladder can bring about organ remodeling because of incomplete reconstitution of depleted smooth muscle cells. Stem cell transplantation could be beneficial to improve smooth muscle cell regeneration and/or modulate the remodeling process. The repair of bladder injury using adult-type stem cells would be useful for adult urological patients but unsuited for neonatal patients, in whom major benefits are likely to derive from fetal-type stem cells. MATERIALS AND METHODS: The smooth muscle cell differentiation potential of fetal-type vs adult-type stem cells was evaluated by injecting green fluorescent protein labeled mesenchymal stem cells from rat amniotic fluid or bone marrow, respectively, in cryo-injured rat bladder walls. RESULTS: At 30 days after transplantation only a few fetal-type or adult-type mesenchymal stem cells gave rise to enteric or vascular smooth muscle cells, whereas most mesenchymal stem cells appeared incapable of specific differentiation. In vitro co-culture experiments of smooth muscle cells with fetal-type or adult-type mesenchymal stem cells selectively labeled with distinct fluorochromes showed the presence of hybrid cells, suggesting that some mesenchymal stem cells can undergo cell fusion. Surprisingly the major effect of rat bone marrow or amniotic fluid mesenchymal stem cell transplantation seemed to be preventing cryo-injury induced hypertrophy of surviving smooth muscle cells. CONCLUSIONS: In this model stem cell transplantation has a limited effect on smooth muscle cell regeneration. Instead it can regulate post-injury bladder remodeling, possibly via a paracrine mechanism.
OBJECTIVE: Feeding intolerance is a common problem in the neonatal intensive care unit (NICU) and some cases might be causally related to atrophic changes in the small bowel mucosa. We speculated that for such patients, feeding tolerance might improve after oral administration of enterocyte growth factors in a sterile, isotonic solution patterned after amniotic fluid. STUDY DESIGN: Twenty neonates meeting criteria for feeding intolerance were eligible for this trial. They were randomized to either Group 1 (test solution) or Group 2 (control). Group 1 received 2.5 ml of test solution/kg every 3 h by oral-gastric or nasal-gastric (OG/NG) tube. This was begun when the patient was NPO because of feeding intolerance and continued until 80 ml/k/day of milk feedings were tolerated, or for a maximum of 7 days. Group 2 received a sham OG/NG administration every 3 h, until 80 ml/k/day of milk feedings were tolerated, or for a maximum of 7 days. Only the bedside nurse and the NICU pharmacist were aware which patients received the test solution and which received the sham administrations. The volumes of milk feedings were increased by order of the attending neonatologist and nurse practitioner. The study outcome was enteral calories/kg/day during and for 7 days after the cessation of the treatments. RESULTS: Eleven patients were randomized to receive the test solution and nine to receive sham administrations. At study entry, the two groups were not different in gestational age, postnatal age, signs of feeding intolerance or cal/k/day taken enterally during the previous 3 days. The study doses were given for an average of just under 6 days (range, 2 to 7 days). During the week following the administrations, the test solution recipients trended toward more enteral calories. Specifically, they had an increase averaging 78+/-20.8 cal/k/day more than before the study, whereas the sham recipients had an increase averaging 55.9+/-33 cal/k/day more than before the study (P=0.05 for a one-sided test and P=0.10 for a two-sided test). The test solution recipients also had a trend toward fewer formula changes than did the sham recipients (P=0.10). In this small, randomized, controlled, masked trial, the administration of a sterile, non-caloric, growth factor containing solution patterned after human amniotic fluid was associated with trends that we interpret as reflecting better tolerance of milk feedings. On this basis, we suggest that a phase III efficacy trial should be accomplished, using the present data for sample size calculations.
In logistic regression analysis of small or sparse data sets, results obtained by classical maximum likelihood methods cannot be generally trusted. In such analyses it may even happen that the likelihood meets the convergence criteria while at least one parameter estimate diverges to +/-infinity. This situation has been termed 'separation', and it typically occurs whenever no events are observed in one of the two groups defined by a dichotomous covariate. More generally, separation is caused by a linear combination of continuous or dichotomous covariates that perfectly separates events from non-events. Separation implies infinite or zero maximum likelihood estimates of odds ratios, which are usually considered unrealistic. I provide some examples of separation and near-separation in clinical data sets and discuss some options to analyse such data, including exact logistic regression analysis and a penalized likelihood approach. Both methods supply finite point estimates in case of separation. Profile penalized likelihood confidence intervals for parameters show excellent behaviour in terms of coverage probability and provide higher power than exact confidence intervals. General advantages of the penalized likelihood approach are discussed.