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Biomedical subjects

M R Harrison

Publications and source records attributed to M R Harrison.

At least 37 records · Page 2Linked to original sources
PubMed2000

Intraoperative radiation therapy for high-risk pediatric neuroblastoma.

PURPOSE: To evaluate the efficacy of intraoperative radiation therapy (IORT) in the treatment of high-risk pediatric neuroblastoma. METHODS AND MATERIALS: Between 1986 and 1998, 23 children received IORT for pediatric neuroblastoma. Electron beam energies ranged from 4 MeV to 16 MeV and median dose was 10 Gy (7-16 Gy). RESULTS: Twenty-one of 23 patients were classified as high-risk. A gross total resection (GTR) was achieved in 18 patients, of whom 6 experienced disease recurrence, 2 of which included a locoregional relapse as a component of failure. Fourteen of 18 patients receiving IORT after a GTR are disease-free survivors. A second subset of 5 patients had a subtotal resection (STR), with gross residual disease remaining after surgery. All 5 patients recurred locally, and all died of their disease. IORT was extremely well-tolerated in our cohort. Surgical resection and IORT resulted in the narrowing of the abdominal aorta and an atrophic kidney in 1 patient. CONCLUSIONS: For high-risk neuroblastoma patients, IORT as the only radiotherapy to the primary, produced excellent local control after a GTR. However, IORT as the sole radiotherapy to the primary was inadequate for patients with extensive adenopathy or an STR. In this setting, we are exploring the use of IORT as a boost in conjunction with external beam radiation therapy.

Adolescent↗
PubMed2000

Slide tracheoplasty for congenital tracheal stenosis: a case report.

BACKGROUND/PURPOSE: A variety of techniques have been used to manage pediatric congenital tracheal stenosis. The authors report the technique of slide tracheoplasty for a child with long congenital tracheal stenosis. METHODS: A 2-year-old male presented with a history of stridor with feeding. Bronchoscopy findings showed 50% stenosis from complete cartilaginous rings, extending from 2.5 cm below the vocal cords to 2 cm above the carina. Through a neck incision, the trachea was exposed from the cricoid to both bronchi and transected at the midpoint of the stenosis. The upper trachea was split anteriorly to the area of stenosis just below the cricoid. The lower trachea was split posteriorly in the midline. Posterior dissection allowed sliding and anastomosis of both tracheal segments while the lateral vascular supply was left intact. A brace was placed to maintain cervical flexion, and the patient underwent extubation in the operating room. RESULTS: He recovered without complication and was dis charged on postoperative day 4. CONCLUSION: Slide tracheoplasty offers several advantages for tracheal reconstruction because it is performed with the native tracheal tissues, can be accomplished through a transverse collar incision, and can repair long stenoses without significant tracheal shortening.

Child, Preschool↗
PubMed2000

Sonographic prognostic factors in fetuses with sacrococcygeal teratoma.

BACKGROUND: A subset of fetuses with sacrococcygeal teratoma (SCT) develops hydrops caused by high-output heart failure. Identification of fetuses at risk for hydrops is important because fetal intervention may reverse the pathophysiology of the disease. To date, no reliable sonographic prognostic factors have been identified. METHODS: An experienced sonologist reviewed the sonographic records of 17 fetuses with SCT referred to the authors' institution. Size of the tumor was measured and corrected for fetal size. The appearance of the tumor (solid versus cystic) and its vascularity were graded on a subjective scale of 1 to 5. RESULTS: Only 4 of 12 fetuses that had hydrops survived; of the survivors, 3 had undergone fetal intervention. All nonhydropic fetuses survived. Fetuses with hydrops had tumors that were mainly solid and highly vascular, whereas nonhydropic fetuses had predominantly cystic tumors with comparatively less vascularity. There was no significant difference in tumor size between these 2 groups. CONCLUSIONS: Fetuses with SCT that are mainly solid in appearance and are highly vascularized have a higher risk of getting hydrops in utero. Tumor size is not an independent prognostic factor.

Coccyx↗
PubMed2000

Fetal bone marrow as a source of stem cells for in utero or postnatal transplantation.

We examined the potential of human fetal bone marrow (FBM) as a source of haematopoietic stem cells for transplantation. The median number of cells obtained between 20 and 24 weeks' gestation was 1.9 x 109 and a median 1.17 x 108 of these cells expressed CD34. Flow cytometry was also used to estimate the content of three different candidate stem cell populations in the tissues older than 20 weeks' gestation. A median 8.8 x 105 CD34++CD38- cells, 1.37 x 106 CD34++CD4+ cells and 2.20 x 106 CD34++CD90+ cells were detected. The content of colony-forming units culture (CFU-C) in the FBM ranged from 2.8 x 104 to 6.0 x 106 per fetus. The CFU-C content could be expanded 50-fold by culture for 1 week in serum-deprived medium and the growth factors kit ligand and granulocyte-macrophage colony-stimulating factor. Positive selection of FBM CD34+/++ cells was achieved using the Baxter Isolex 50 device. An average purity of 82% and yield of up to 19% of CD34+/++ cells was achieved. T cells were depleted by 99.84%. Analysis of candidate stem cell populations and primitive CFU-C suggested a preferential enrichment of these cells over the total population of CD34+/++ cells. All FBM samples were found to be free of microbial contamination at the time of harvest and after selection of CD34+/++ cells. Thus, FBM is a safe source of stem cells. The large number of progenitors and candidate stem cells that can be obtained from FBM makes it suitable for in utero and possibly postnatal transplantation.

Antigens, CD34↗
PubMed2000

Successful fetal sacrococcygeal teratoma resection in a hydropic fetus.

BACKGROUND/PURPOSE: The development of hydrops in a fetus with a sacroccocygeal teratoma (SCT) usually is a predictor of fetal demise; in utero resection may offer the only chance of survival. Although the authors had performed this procedure in 3 previous cases, they had no long-term patient survival. The authors report a successful case of in utero resection of a fetal sacrococcygeal teratoma. METHODS: The authors resected a fetal SCT from a 23-weeks-gestation hydropic fetus, using gradually tightening umbilical tapes at the tumor base, electrocautery, and careful sharp dissection. After a blood transfusion, the fetus suffered cardiac arrest but was resuscitated and returned to the uterus. RESULTS: Postoperatively, residual SCT growth ceased, and hydrops rapidly resolved. Five weeks after the procedure, the infant was delivered because of preterm labor, and, after resection of residual SCT, was discharged home at 3 months of age. She is now a healthy 3 year old. CONCLUSION: This case shows that successful fetal SCT resection and long-term patient survival is possible.

Electrocoagulation↗
PubMed2000

Tracheal stenosis: the long and the short of it.

PURPOSE: The aim of this study was to present slide tracheoplasty as the procedure of choice for tracheal stenosis. From 1990 through 1997, patients referred to University of California, San Francisco for tracheal stenosis were managed by resection and anastomosis. During this period, other centers reported successful use of slide tracheoplasty and, from 1998 to 1999, we performed 3 slide tracheoplasties in addition to 3 more resection and anastomosis procedures. METHODS: Between 1990 and 1999, 9 patients with tracheal stenosis of varying lengths underwent surgery at the University of California, San Francisco. They were treated surgically with either resection and anastomosis or with slide tracheoplasty. RESULTS: Two of the 6 patients treated by resection and anastomosis had an anastomotic breakdown; all 3 patients undergoing slide tracheoplasty did not have anastomotic problems. Technically, a slide tracheoplasty has only one half the tension distributed over an oblique anastomosis that is more than the circumferential length of a resection and anastomosis approach. CONCLUSION: Based on these results, a slide tracheoplasty may be the procedure of choice for tracheal stenosis, whether long or short.

Adolescent↗
PubMed2000

Successful resuscitation during fetal surgery.

After in utero resection of a sacrococcygeal teratoma coupled with a transfusion of packed red blood cells, a 23-week-gestation fetus had bradycardia. Chest compressions were begun and epinephrine, atropine, and sodium bicarbonate were given, while the fetus remained bathed in warm saline. After 3 rounds of drugs, and just before withdrawing support, the fetal heart resumed beating and normal cardiac function. Based on to this case, the authors developed a resuscitation protocol for fetal surgery.

Cardiopulmonary Resuscitation↗
PubMed2000

Hindbrain herniation develops in surgically created myelomeningocele but is absent after repair in fetal lambs.

OBJECTIVE: The purpose of our study was to determine whether prenatal repair of myelomeningocele prevents or reverses hindbrain herniation in the sheep model. STUDY DESIGN: A myelomeningocele was surgically created in fetal sheep. One group was repaired later in utero; the others were delivered without repair. After delivery, lambs were assessed for the presence of hindbrain herniation. RESULTS: In all lambs that had not undergone repair of the myelomeningocele, severe hindbrain herniation developed, whereas the brains of all lambs that had undergone fetal repair were normal. CONCLUSION: Prenatal repair of myelomeningocele prevents or reverses development of hindbrain herniation in the fetal lamb model.

Animals↗
PubMed2000

Normal and hypoplastic fetal lungs: volumetric assessment with prenatal single-shot rapid acquisition with relaxation enhancement MR imaging.

PURPOSE: To determine which parameters are most closely correlated with normal fetal total lung volume and to investigate the use of these parameters in the evaluation of fetal pulmonary hypoplasia. MATERIALS AND METHODS: Single-shot rapid acquisition with relaxation enhancement (RARE) magnetic resonance (MR) imaging was used to perform planimetric measurement of total lung volume in 46 fetuses at 18-32 weeks gestation. Total lung volume was correlated with gestational age, and biometric parameters in fetuses were correlated with normal chest findings at ultrasonography (US) (n = 24). This analysis was used to evaluate relative lung volume in fetuses suspected of having pulmonary hypoplasia (n = 22). RESULTS: Normal fetal total lung volume was strongly correlated with liver volume measured at MR imaging (r = 0.94), fetal weight estimated at US (r = 0.93), head circumference measured at US (r = 0.90), and gestational age (r = 0.87). In fetuses suspected of having pulmonary hypoplasia, the relative lung volume varied from 4.6% to 81.6% when the observed total lung volume was expressed as a percentage of the predicted total lung volume. CONCLUSION: Normal fetal total lung volume is strongly correlated with biometric measurements. Relative fetal lung volume can be calculated by expressing the observed volume as a percentage of the predicted volume calculated from biometric measurements; knowledge of the relative fetal lung volume assists in the confirmation and quantification of fetal pulmonary hypoplasia.

Adolescent↗
PubMed2000

Congenital diaphragmatic hernia without herniation of the liver: does the lung-to-head ratio predict survival?

The purpose of the present study was to determine the ability of lung-to-head ratio to predict survival and need for extracorporeal membrane oxygenation support in fetuses with left congenital diaphragmatic hernia without herniation of the liver into the chest. The perinatal records of 20 fetuses with isolated left congenital diaphragmatic hernia without herniation of the left lobe of the liver into the chest were reviewed. Fetuses were stratified into two groups depending on lung-to-head ratio: those with a ratio of less than 1.4 (historically a poor prognosis group) and those with a ratio of greater than 1.4. The outcome of both groups was compared with chi-square analysis. Eight of 11 fetuses with a lung-to-head ratio greater than 1.4 survived, whereas 8 of 9 fetuses with a ratio of less than 1.4 survived. No differences were noted in the need for extracorporeal membrane oxygenation support or survival between the two groups. Fetuses with a prenatally diagnosed left congenital diaphragmatic hernia without herniation of liver into the chest have a favorable prognosis even in the presence of a low lung-to-head ratio.

Female↗
PubMed1999

Fetal neurenteric cyst causing hydrops: case report and review of the literature.

Routine prenatal ultrasound revealed a unilocular cystic mass associated with upper thoracic hemivertebrae that grew to 6 cm at 28 weeks and was associated with hydrops. A thoraco-amniotic shunt decompressed the cyst and resolved the hydrops, but the shunt occluded 17 days later. Preterm labour led to vaginal delivery at 31 2/7 weeks. Postnatally, the cyst was decompressed by thoracentesis due to respiratory distress. It was resected on day four of life. Severe tracheobronchomalacia was present post-operatively, presumably due to prenatal mass effect of the cyst. At one year of age, the child has recovered completely without adverse respiratory or neurological sequelae.

Adult↗
PubMed1999

Effects of nitroglycerin and indomethacin on fetal-maternal circulation and on fetal cerebral blood flow and metabolism in sheep.

OBJECTIVE: Our purpose was to evaluate the effects of maternal administration of nitroglycerin and indomethacin on maternal and fetal hemodynamics and on fetal cerebral blood flow and metabolism in sheep. STUDY DESIGN: Invasive vascular and fetal carotid flow monitoring was established in 12 gravid ewes. Isotonic sodium chloride solution, nitroglycerin, and indomethacin were infused maternally, and maternal and fetal heart rate, blood pressure, blood gas values, fetal carotid blood flow, and flow variability were measured. Fetal cerebral uptake of oxygen, glucose, and lactate were calculated. RESULTS: Nitroglycerin infusion caused a significant increase in maternal and fetal heart rate and a significant decrease in maternal and fetal mean arterial pressure at a dosage of 10 microram/kg per minute, without a change in blood gas values. Neither drug had any effect on fetal carotid blood flow, flow variability, or cerebral substrate metabolism. CONCLUSION: Maternal administration of nitroglycerin and indomethacin caused no adverse maternal or fetal circulatory changes and did not alter fetal carotid blood flow or substrate metabolism.

Animals↗
PubMed1999

Esophageal lung with multiple congenital anomalies: conundrums in diagnosis and management.

BACKGROUND/PURPOSE: Communicating bronchopulmonary foregut malformations (CBPFM) are a diverse group of potentially devastating congenital anomalies with anatomy that may be difficult to delineate. The authors present a case that illustrates conundrums in the diagnosis and management of these complex disorders. METHODS: A term baby had esophageal atresia (EA), tracheoesophageal fistula (TEF), and tetralogy of Fallot. Initially, a gastrostomy was performed, and a balloon catheter was inserted through the endotracheal tube to occlude the fistula until the patient was hemodynamically stable. Subsequently, the fistula was ligated. Postoperatively, the left lung collapsed, and bronchoscopy showed an atretic left mainstem bronchus. Repeat thoracotomy showed that the fistula ligation was intact. Air was introduced through the gastrostomy tube, and, surprisingly, the left lung inflated, indicating the left mainstem bronchus arose from the esophagus distal to the ligated TEF. RESULTS: Despite reopening this fistula, ventilation remained poor, and support was withdrawn. Autopsy findings confirmed a unilobed left lung arising from the esophagus, EA, TEF, an atretic left mainstem bronchus, tetralogy of Fallot, and DiGeorge syndrome. CONCLUSIONS: This is the first report of a combination of EA and distal TEF with a second CBPFM involving the esophagus and the entire left lung. Successful correction of these anomalies will require extensive delineation of the anatomy to plan an operative strategy.

Abnormalities, Multiple↗
PubMed1999

A strategy for primary reconstruction of long gap esophageal atresia using neonatal colon esophagoplasty: a case report.

Treatment options for long gap esophageal atresia without tracheoesophageal fistula generally require several stages over many months. An early neonatal vascularized conduit would allow a tension-free anastomosis, but the precarious blood supply of the neonatal bowel makes mobilization and immediate interposition hazardous. This report describes the successful application of a strategy for primary reconstruction in the neonate using a short piece of colon mobilized into the mediastinum for subsequent delayed anastomosis.

Colon↗
PubMed1999

One-stage correction of high imperforate anus in the male neonate.

PURPOSE: The aim of this study was to examine the feasibility, safety, and short-term outcome of complete one-stage repair of high imperforate anus in the newborn boy. METHODS: A retrospective review was conducted of five full-term male infants who underwent posterior sagittal anorectoplasty without a colostomy within the first 48 hours of birth. Preoperative imaging was performed to assess associated anomalies. All infants underwent cystoscopy before the perineal operation to determine the level of the urinary tract fistula, if present. After completion of the anoplasty, all were turned supine and the colon irrigated free of meconium. Follow-up ranged from 10 to 24 months. RESULTS: Laparotomy was not required for any patient. Three patients had a rectoprostatic urethral fistula, one a rectovesical fistula, and one no fistula (common wall at level of prostate). Tapering rectoplasty was required for only the one patient with a rectovesical fistula. There were no intraoperative complications. All patients passed stool within 12 hours after operation and took full feeding by 48 hours. The average hospital stay was 7 days. Postoperative and stenosis occurred in one patient secondary to parental noncompliance with the postoperative dilation regimen. There were no perineal wound complications. All patients have a strong urinary stream and defecate spontaneously without the aid of oral medication or rectal stimulation or enemas. CONCLUSIONS: One-stage repair of high imperforate anus in the male neonate is feasible without short-term genitourinary or gastrointestinal morbidity. Whether it is preferable compared with a delayed (two or three stage) repair depends on ultimate long-term anorectal function, which cannot be assessed for several years.

Anal Canal↗
PubMed1999

Transabdominal oxygenation using perfluorocarbons.

PURPOSE: Evaluation of the intraabdominal (intraperitoneal and intraluminal) administration of oxygen-saturated perfluorocarbon on both portal and arterial blood oxygenation. METHODS: Eight male rabbits were divided into the test (n = 5) and control (n = 3) groups. Each underwent intrajejunal, intraperitoneal, and intravascular (artery, portal vein) catheter placements along with ligation of the duodenum and the terminal ileum under general anesthesia. The test group received oxygen-saturated perfluorotripropylamine (FTPA), and the control group received oxygen desaturated FTPA. The oxygen delivery was assessed by serial blood gas measurements before and after the administration of FTPA. RESULTS: The administration of oxygen-saturated FTPA significantly increased the partial pressure of oxygen within both the arterial and the portal venous blood (PaO2, PpVO2) without significant changes in PCO2 values. Oxygen desaturated FTPA failed to show any effects on blood gas values. Compared with oxygen desaturated FTPA, oxygen-saturated FTPA increased PaO2, PpVO2, and oxygen saturation (artery, portal vein) significantly at some, but not all of the time-points measured. CONCLUSIONS: The intraabdominal administration of saturated FTPA improved both the portal venous and the arterial oxygenation. This new mode of oxygenation may be helpful as an adjunct to conventional oxygen delivery systems.

Animals↗