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Biomedical subjects

T E MacGillivray

Publications and source records attributed to T E MacGillivray.

9 recordsLinked to original sources
PubMed2001

Long-term results and determinants of mortality after surgery for native and prosthetic valve endocarditis.

BACKGROUND AND AIM OF THE STUDY: The study aim was to describe the long-term results and determinants of mortality after operative treatment of native and prosthetic valve endocarditis at a single institution. METHODS: Between March 1985 and October 1999, 171 patients underwent surgery for native (NVE) or prosthetic valve endocarditis (PVE). NVE was present in 98 patients (57%), and PVE in 73 patients (43%). Mean follow up was 5.6+/-3.9 years (range: 0 to 15 years). RESULTS: Overall hospital mortality was 9.9% (n = 17). Hospital mortality was higher among patients with PVE (15.1%) than those with NVE (6.1%; p = 0.05). Overall survival at 10 years was 46+/-5%. Patients with NVE had a higher 10-year survival rate (53+/-7%) than those with PVE (37+/-7%; p = 0.02). At 10 years, overall freedom from any late complication was 47+/-6% and from residual or recurrent endocarditis was 78+/-5%. Predictors of hospital death were emergency surgery (p <0.003) and preoperative renal insufficiency (p <0.008). Predictors of late death were age >70 years (p <0.002), renal failure (p <0.03) and fungal endocarditis (p <0.04). CONCLUSION: These findings demonstrate the increased perioperative, as well as postoperative, risks associated with PVE versus NVE. Cardiac and extracardiac manifestations of the disease, as well as fungal organisms, but not the activity of the endocarditis, were significant adverse determinants of late outcome.

Endocarditis↗
PubMed1995

An adult-fetal skin interface heals without scar formation in sheep.

BACKGROUND: Fetal skin heals by regeneration rather than by adult-type scarring. Prior studies indicate that scarless healing is an intrinsic property of fetal tissue. METHODS: To answer the question of whether fetal tissue could influence the healing of adjacent adult tissue, adult sheepskin was transplanted on the backs of 60-days' gestation fetal lambs (term, 145 days). At time points 1, 3, 7, 14, 21, 28, 42, 56, and 63 days after transplantation, the grafts were harvested and the interfaces between adult and fetal skin were analyzed. RESULTS: The adult-fetal interface healed without scar formation. Control fetal sheep autograft (fetal-fetal) interfaces healed without scar, and adult sheep autograft (adult-adult) interfaces healed with scar. CONCLUSIONS: These results suggest that the juxtaposed fetal tissue prevented scar formation at the adult-fetal interface. We hypothesize that fetal cellular and matrix factors permit adjacent wounded adult tissue to heal without scar. These factors, once characterized, might be used clinically to induce scarless healing in children and adults.

Adult↗
PubMed1994

Vascular changes with in utero correction of diaphragmatic hernia.

In utero surgical correction of fetal diaphragmatic hernia is a new therapeutic alternative for selected prenatally diagnosed patients. With increasing experience, the authors have found that fetuses with herniation of the liver through the diaphragmatic defect have a high incidence of perioperative death. The hypothesis was that reduction of the liver during fetal diaphragmatic hernia repair caused distortion of fetal vascular anatomy resulting in fetal demise. To study this, the authors performed angiograms through the umbilical vein in fetal and neonatal cadavers, with and without diaphragmatic hernias, and simulated in utero repair. Large fetal congenital diaphragmatic hernias can be associated with dramatic changes in the vascular anatomy of the liver. The liver does not simply rotate up into the chest through a diaphragmatic defect; instead, the liver more likely develops in the chest, with its vascular anatomy situated accordingly. Attempts to reduce a herniated liver can result in significant distortion of the fetal vasculature, leading to fetal death. Techniques to prevent vascular compromise during hepatic manipulation may improve the outcome for fetuses during in utero repair of diaphragmatic hernias.

Angiography, Digital Subtraction↗
PubMed1994

Phenotypic and functional features of myofibroblasts in sheep fetal wounds.

The myofibroblast is a mesenchymal cell with functional and structural characteristics in common with fibroblasts and smooth muscle cells. These cells play a critical role in wound closure and in the pathologic sequelae of healing. It has been shown in adult humans and experimental animals that the myofibroblast expresses alpha -smooth muscle actin (ASMA) temporarily during wound contraction and more persistently during fibrocontractive diseases; however, it is unclear whether this cell makes any contribution to tissue repair in utero. Experimental work in fetal animal models has demonstrated that wound repair in fetal skin occurs by reconstitution of epidermal appendages and organized restoration of the dermal collagen network. Fetal lamb wound healing studies have shown that a transition from scarless tissue repair to healing with scar formation occurs late in gestation. In this study we examined the ontogeny of myofibroblasts in fetal lamb wounds at early through late gestation, using transmission electron microscopy (TEM) and ASMA immunohistochemistry. Dramatic differences were observed in ASMA content of early as compared to late gestation fetal wound granulation tissue: ASMA was absent in wounds made at 75 days gestation but was present in progressively greater amounts in wounds made at 100 and 120 days gestation (term = 145 days). TEM studies also demonstrated progressive development and organization of microfilament bundles. Early in development microfilament bundles were sparse and disorganized, but as gestation progressed the bundles became more prevalent and formed tightly parallel arrangements. The organization of microfilament bundles was also accompanied by fibronexus formation.(ABSTRACT TRUNCATED AT 250 WORDS)

Actins↗
PubMed1993

Chronic fetal vascular access.

Intensive management of the fetus is limited by our inability to achieve access to the fetal circulation. Using laparoscopic surgery, we can maintain long-term access to the fetal circulation by extra-amniotic catheterisation of chorionic vessels in third-trimester monkeys and early-gestation sheep. We can sample fetal blood, continuously measure blood pressure, and infuse drugs without complications. Safe vascular access will permit assessment of fetal status during fetal surgical procedures and improve postoperative monitoring.

Animals↗
PubMed1993

Disappearing fetal lung lesions.

Cystic adenomatoid malformations and sequestrations of the lung are uncommon but potentially devastating problems of the fetus and neonate. We have followed over 50 cases of fetal lung masses from the time of prenatal diagnosis. Serial prenatal ultrasonography demonstrated that 9 large pulmonary lesions dramatically decreased in size or disappeared completely. We conclude that the natural history of prenatally diagnosed fetal lung masses is highly variable. A huge mass associated with fetal hydrops has a dismal outcome. If hydrops is not present, then the initial impression concerning prognosis may not accurately predict outcome, because there may be marked improvement during fetal life.

Adult↗
PubMed1993

Correction of congenital diaphragmatic hernia in utero: VI. Hard-earned lessons.

Extensive experimental work suggests that repair of congenital diaphragmatic hernia (CDH) in utero may salvage severely affected fetuses who otherwise have a high expected mortality despite optimal postnatal care including extracorporeal membrane oxygenation (ECMO). We have reported that repair of CDH in utero is physiologically sound and safe for the mother, but technically difficult especially when the liver is herniated into the fetal chest. In the 3 years since our last report (1989 to 1991), 61 additional patients were referred for consideration of in utero repair. Fetal repair was attempted in 14 with severe isolated left CDH diagnosed before 24 weeks gestation. Five fetuses died intraoperatively, from technical problems related to reduction of incarcerated liver and uterine contractions--problems which have subsequently been surmounted. Nine patients were successfully repaired. Four babies survived, two delivered prematurely and died, and three died in utero within 48 hours of repair. Intraoperative technical problems have been overcome; the factors limiting successful outcome are postoperative physiologic management of the maternal-fetal unit and effective tocolysis to control preterm labor.

Fetal Death↗
PubMed1992

Fetoscopic surgery for the treatment of congenital anomalies.

Fetoscopic techniques may broaden the indications for prenatal surgical intervention by obviating the risks of hysterotomy. For example, congenital obstructive uropathy has been treated by open vesicostomy and percutaneous catheter placement. The open approach is appropriate only for highly selected fetuses because of the inherent risks, whereas catheter drainage, though a safer procedure, is only useful for short-term therapy late in gestation due to frequent catheter obstruction and migration. The natural history of congenital obstructive uropathy mandates the need for improved therapy earlier in gestation, in order to salvage fetuses who would otherwise die of renal failure and pulmonary hypoplasia. We have developed a potential solution to this problem in which surgery is performed on the fetus without the risks of hysterotomy. Endoscopic fetal surgery uses a telescopic lens and operating instruments that are passed through small "ports" in the uterus. A bubble of CO2 is used to displace amniotic fluid and provides excellent visualization in a magnified field. This approach is considerably less invasive than open fetal surgery and, therefore, is less likely to provoke preterm labor. In this study we corrected obstructive uropathy in midgestation fetal lambs using a new, expandable wire mesh stent that is placed endoscopically and should provide more reliable bladder drainage than existing catheters. The fetoscopic surgical approach can potentially expand the indications for in utero surgery by decreasing fetal risks, facilitating intervention earlier in gestation, and reducing preterm labor. As a consequence, the potential now exists to correct non-life-threatening malformations in utero.

Animals↗