Component Engineering for an Implantable System

Wang, Qingtian; Yambe, Tomoyuki; Shiraishi, Yasuyuki; Esashi, Masayoshi; Haga, Youichi; Yoshizawa, Makoto; Sato, F.; Matsuki, H.; Imachi, Kou; Abe, Yusuke; Sasada, Hiroshi; Nitta, Shin Ichi

doi:10.1111/j.1525-1594.2004.07383.x

Cited by 7 publications

(4 citation statements)

References 10 publications

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“…These functional studies could be combined usefully with further studies of differentiation by electron microscopy to determine the maturity of the air-blood barrier. Last, the use of exteriorized fetal catheters is not applicable to humans and significant technologic development is required to create a system comprising a detachable balloon (78) and a miniaturized remotely activated implantable pump (79), which could be used in human gestations.…”

Section: Discussionmentioning

confidence: 99%

Rescue of the Hypoplastic Lung by Prenatal Cyclical Strain

Nelson

Hajivassiliou

Haddock

et al. 2005

Am J Respir Crit Care Med

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We determined the effects of sustained and cyclical prenatal mechanical strain on the hypoplastic lung of the ovine model of congenital diaphragmatic hernia. Over a period of 4 weeks in late gestation, repeated cyclical tracheal occlusion for 23 hours with 1-hour release stimulated minimal growth, but promoted maturation with the development of a saccular lung. In contrast, a cycle consisting of 47 hours with 1-hour release induced optimal lung growth and morphologic maturation of the hypoplastic lung parenchyma. Sustained occlusion resulted in exaggerated lung growth, exceeding that of unaffected controls, and abnormal alveolar development. The extent of induction of lung growth by mechanical strain was inversely proportional to the number of alveolar type II cells remaining in the lung epithelium. These studies show that, although mechanical strain is capable of inducing lung growth and differentiation, cyclical strain is a prerequisite for normal development and that mechanically induced growth occurs at the expense of the alveolar type II cell. We conclude that cyclical strain may allow optimal alveolar development while maintaining a population of alveolar type II cells and may thus facilitate an improvement in postnatal lung function in infants with congenital diaphragmatic hernia.

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Section: Discussionmentioning

confidence: 99%

Rescue of the Hypoplastic Lung by Prenatal Cyclical Strain

Nelson

Hajivassiliou

Haddock

et al. 2005

Am J Respir Crit Care Med

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“…Wang et al. (17), for example, have designed a preliminary‐stage implantable artificial heart with modular architecture. Each of the modules—such as a mechanical assistance device pumping unit, a sensory system that detects information in the body, an automatic control system performing the drive control, a transcutaneous energy transmission system, and a secondary implantable battery—was designed to perform a particular and independent function from other modules.…”

Section: Problems Arising From the Integral Architecture Of Bioartifimentioning

confidence: 99%

Modularity in Developmental Biology and Artificial Organs: A Missing Concept in Tissue Engineering

et al. 2011

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Tissue engineering is reviving itself, adopting the concept of biomimetics of in vivo tissue development. A basic concept of developmental biology is the modularity of the tissue architecture according to which intermediates in tissue development constitute semiautonomous entities. Both engineering and nature have chosen the modular architecture to optimize the product or organism development and evolution. Bioartificial tissues do not have a modular architecture. On the contrary, artificial organs of modular architecture have been already developed in the field of artificial organs. Therefore the conceptual support of tissue engineering by the field of artificial organs becomes critical in its new endeavor of recapitulating in vitro the in vivo tissue development.

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“…We have recently shown that prenatal cyclical occlusion for a repeated regimen of 47 hour occlusion with 1 hour release performed between 110 and 138 days gestation induces optimal lung growth and differentiation in the ovine model of CDH (Figure 2). 168 At present the cellular mechanisms whereby increased fetal lung expansion leads to increased rates of lung tissue growth and differentiation are unknown. At present this system is however not applicable to humans as exteriorized fetal catheters were used.…”

Section: Cdh Lung Response To Tracheal Occlusionmentioning

confidence: 99%

Fetoscopic Surgery for in-Utero Management of Congenital Diaphragmatic Hernia

Nelson

Cameron

Deprest³

2006

Fet. Matern. Med. Rev.

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INTRODUCTIONUntil recently two possibilities were available to the expectant parents of a fetus diagnosed with a congenital diaphragmatic hernia: termination of pregnancy or continuation of the pregnancy until term with a potential change in the place of delivery. Open fetal surgery has been used to treat a growing number of congenital malformations with life-threatening or highly morbid consequences including congenital diaphragmatic hernia. 1 However, its effectiveness is limited by the occurrence of preterm labour, chorioamniotic membrane separation, preterm prelabour rupture of the membranes and altered fetal homeostasis. 2 These problems were the impetus for the development of minimal access fetal surgery. Developments in endoscopic surgical technology over the past three decades have provided the opportunity to develop techniques adapted for prenatal fetal intervention. 3 RATIONALE FOR FETOSCOPIC SURGERYExperimental studies on the effect of minimal access fetal surgery suggest that it reduces preterm labour and achieves better maintenance of fetal and maternal homeostasis. 4 With respect to preterm labour fetoscopic access in mid-trimester Rhesus monkeys did not result in any significant uterine contractions by 24 hours post-operatively. 5 Subsequent recordings of myometrial activity were repeated during the third trimester, and no premature contractions were noted. In contrast, Luks and colleagues studying third trimester sheep found that uterine contractions were present 52% of the time after maternal laparotomy irrespective of whether a hysterotomy or fetoscopic access using three ports was performed. 6 These myometrial contractions were noted in response to access only, as no fetal manipulation was undertaken. The primate uterus resembles the human uterus much more closely than the ovine and is generally accepted as a good model for studies into human parturition, questioning the application of ovine myometrial activity studies to the human situation.With respect to maternal-fetal homeostasis, Luks demonstrated in the same study a significant 27% reduction in uterine blood flow and utero-placental oxygen delivery with hysterotomy creation, whereas endoscopic access had no effect. 6 When uterine artery flow and thus oxygen delivery is reduced to 70% of control, there is a shift in fetal blood flow distribution, a decrease in fetal pH and an increase in serum lactate. 7 It is likely that oxygen delivery would be further impaired during open fetal surgery, by manipulation of the uterus, active pressure on uterine vessels and traction or compression of the umbilical cord. Therefore the endoscopic approach, which does not alter uteroplacental oxygen delivery, would be preferable. Clinical experience with human fetoscopic surgery reflects this experimental work. Fetoscopic intervention produces less preterm labour with less use of tocolytics, decreased maternal hospital stay and decreased maternal complications related to tocolysis. 8

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Component Engineering for an Implantable System

Cited by 7 publications

References 10 publications

Rescue of the Hypoplastic Lung by Prenatal Cyclical Strain

Rescue of the Hypoplastic Lung by Prenatal Cyclical Strain

Modularity in Developmental Biology and Artificial Organs: A Missing Concept in Tissue Engineering

Fetoscopic Surgery for in-Utero Management of Congenital Diaphragmatic Hernia

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