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Biomedical subjects

H Rice

Publications and source records attributed to H Rice.

13 recordsLinked to original sources

Management of cholelithiasis in pediatric patients who undergo bone marrow transplantation.

PURPOSE: The aim of this study was to determine the incidence, risk factors, and proper management for asymptomatic cholelithiasis in children undergoing bone marrow transplantation (BMT). METHODS: The authors reviewed retrospectively the records of 575 children who underwent bone marrow transplantation at a University bone marrow transplantation unit (BMT) unit between February 1991 and October 1999. Of these patients, 235 underwent abdominal ultrasonography for evaluation of jaundice, sepsis, abdominal pain, or metastasis. To identify risk factors for cholelithiasis, the authors stratified the patients based on their disease and treatment regimen. Finally, the authors analyzed the natural history and management of BMT children with cholelithiasis. RESULTS: The authors identified 20 cases of cholelithiasis (8.5%) in the 235 BMT patients who underwent ultrasonography. Children who underwent BMT to treat bone marrow failure showed a significantly increased risk of cholelithiasis compared with children treated for malignancy (27% v 7.4%; P<.01). Most children (85%) with gallstones did not require surgical intervention. Specifically, 9 (45%) died from their primary disease, 5 (25%) showed sonographic resolution of their gallstones, and 3 (15%) underwent follow-up nonoperatively with persistent cholelithiasis. Three of the 20 patients with gallstones (15%) had signs of acute cholecystitis and underwent surgery. There were no surgical complications or deaths in the operative group. CONCLUSIONS: Cholelithiasis occurs at a high incidence in pediatric bone marrow transplant patients. Children undergoing BMT for bone marrow failure are at higher risk of having gallstones than those being treated for malignancy. Finally, these data support a strategy of nonoperative management for asymptomatic cholelithiasis in this highly selected group of patients.

Bone Marrow Transplantation↗

Effects of canine donor heart preservation temperature on posttransplant left ventricular function and myocardial metabolism.

The generally accepted method of preserving donor heart integrity during transfer is to arrest it with cold cardioplegic solution, then store it in a plastic bag immersed in an iced electrolyte solution. Temperatures between 0 degree C and 4 degrees C are maintained by this method until the heart is transplanted. Although profound hyperthermia best inhibits metabolic processes, it may damage the myocardium. Higher myocardial temperatures may be more advantageous and may result in better preservation. The efficacy of this hypothesis has been investigated in a canine model. The hearts of 40 dogs were isolated, arrested with cold cardioplegia, removed from the animal, and stored at different temperature ranges from 0-3 degree C to 12-15 degrees C for 4 hr. After this time period, the hearts were transplanted into a recipient animal in the cervical heterotopic position. The degree and speed of myocardial functional recovery were monitored by measuring end-systolic elastance generated from pressure-diameter loops using sonomicrometry techniques. Myocardial metabolism was studied simultaneously by monitoring coronary flow, O2, glucose, lactate, pyruvate, and free fatty acid uptakes. The results were compared with those from a control group of hearts transplanted immediately after their removal. Our results indicate that donor heart function was significantly depressed 30 min after heterotopic transplantation, but returned to "control" levels after 2 hr when stored between 0 degrees C and 6 degrees C. Myocardial function remained significantly depressed throughout the 2-hr recovery period in hearts stored at higher (6-15 degrees C) temperatures. Hearts stored at all temperatures continued to extract glucose, lactate, and free fatty acids, but produced significantly higher levels of pyruvate at higher storage temperatures, which may be related to the favored use of free fatty acids. In conclusion, donor hearts stored at colder temperatures for 4 hr regain complete left ventricular function faster than hearts stored at higher temperatures. Our experiments support the presently applied methods of donor heart preservation for 4 hr.

Animals↗

Long-term repopulating ability of xenogeneic transplanted human fetal liver hematopoietic stem cells in sheep.

We previously reported on the successful engraftment and long-term multilineage expression (erythroid, myeloid, lymphoid) of human fetal liver hematopoietic stem cells in sheep after transplantation in utero. That the engraftment of long-term repopulating pluripotent stem cells occurred in these animals was shown here by the fact that transplantation of human CD45+ cells isolated from bone marrow of these chimeric animals into preimmune fetal sheep resulted in engraftment and expression of human cells. Marrow cells were obtained from three chimeric sheep at 3.2-3.6 yr after transplant. The relative percentage of human CD45+ cells present in these marrows was 3.3 +/- 0.32%. A total of 29 x 10(6) CD45+ cells were isolated by panning, pooled, and transplanted into six preimmune sheep fetuses (4.8 x 10(6) cells/fetus). All six recipients were born alive. Hematopoietic progenitors exhibiting human karyotype were detected in marrows of two lambs soon after birth. Cells expressing human CD45 antigen were also detected in blood and marrow of both lambs. Human cell expression has been multilineage and has persisted for > 1 yr. These results demonstrate that the expression of human cells in this large animal model resulted from engraftment of long-term repopulating pluripotent human stem cells.

Animals↗

Evaluation of Nissen fundoplication in neurologically impaired children.

The value of performing Nissen fundoplication in neurologically impaired children is a controversial issue. To evaluate the benefit of fundoplication in these children, hospital records were reviewed for 77 children who underwent fundoplication for gastroesophageal reflux (GER). Fifty-two children were neurologically impaired; 25 children had no neurological impairment. Impaired children had significantly fewer hospital admissions (1.8 v 0.7; P less than .005) and total days of hospitalization (36 v 14; P less than .005) during the first postoperative 6 months, compared with the immediate preoperative 6-month period. Normal children had fewer hospital admissions and days postoperatively, but the difference was not significant. Impaired children with preoperative failure to thrive (FTT had significantly increased average monthly weight gain over the first 6-month period postoperatively, compared with preoperative growth rate (3.0% v 0.9% of total body weight; P less than .05). Average monthly weight gain at 1 and 2 years postoperatively was not significantly different from preoperative values for impaired children. Growth rate of normal children with FTT did not change significantly postoperatively. Symptomatic relief was comparable in the normal and impaired children. Perioperative mortality was 0% in the normal children and 6% in the impaired children. This study demonstrates that Nissen fundoplication in neurologically impaired children with GER can be performed safely, reduces the frequency of hospitalization, and improves short-term weight gain.

Child↗

Enhancing the applicability and effectiveness of intraaortic balloon counterpulsation.

Severe maneuvers designed to enhance the applicability and effectiveness of intraaortic balloon pulsation are presented. (1) Insertion of balloon catheter directly into the ascending aorta. The technique uses an indwelling silastic snare that allows direct insertion of a balloon catheter into the ascending aorta in the course of open heart operations without the necessity of returning the patient to the operating room and reopening the chest at the time of balloon catheter removal. (2) Elimination of electric artifacts in the course of intraaortic balloon assist. A method is presented that utilizes optical rather than electric signals to operate the intraaortic balloon pump and eliminates pacer interference as well as other electrical artifacts. (3) Enhancing assist effectiveness by balloon positioning. In a series of clinical observations, it was found that the effectiveness of balloon assist may be enhanced by as much as 75% by appropriate positioning. The previously held concept that placing the balloon in a subclavian location is optimal is challenged and it is recommended that the proper position of the balloon catheter be determined by using appropriate hemodynamic measurements in different locations. (4) Control of bleeding following removal of percutaneously inserted transfemoral balloon catheter. The technique utilizes a balloon catheter which is introduced into the puncture hole of the femoral artery after minimal surgical dissection and allows direct suturing of the bleeding source.

Artifacts↗

To cure racism.

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Black or African American↗

Comparison of intermittent warm and cold blood perfusion during hypothermic myocardial preservation on functional and metabolic recovery.

Numerous techniques are used to maintain intraoperative heart viability. The studies presented here evaluated heart function and metabolism after various periods of preservation up to 4 hours with intermittent warm and cold blood perfusion. Using a heterotopic heart model cooled to 10 degrees C and maintained for 1, 2, 3, and 4 hours, various preservation techniques were compared. Changes in myocardial metabolism were determined from substrate uptakes and biopsy samples of the left ventricular muscle for high-energy phosphates. Preservation techniques included: (1) sustained hypothermia, (2) 1 or 2 hours of sustained warm blood perfusion with fibrillation, (3) intermittent cold blood perfusion during 2, 3, and 4 hours of preservation, (4) intermittent warm blood perfusion during 2, 3, and 4 hours of preservation and (5) a control group (no preservation). Normothermic fibrillation had no effect on postpreservation functional or metabolic parameters. Sustained hypothermia reduced functional recovery proportional to the length of ischemia. The cold intermittent procedures maintained function and metabolism better than sustained hypothermia, while warm intermittent preservation maintained function and metabolism at control levels throughout the recovery period for all preservation techniques. Changes in ATP mirrored the functional changes. Creatine phosphate (CP) was markedly reduced during heart isolation and preservation and exceeded the control by 100% during reperfusion. For operative procedures of 2 hours or less, functional and metabolic recovery was not affected by the various preservation methods applied. Warm intermittent perfusion during hypothermic preservation offered the best protection for the myocardium. The warming cycles during hypothermia may provide some degree of preconditioning and protect the myocardium during reperfusion.

Animals↗