Biomedical subjects

Christopher B White

Publications and source records attributed to Christopher B White.

6 recordsLinked to original sources

PubMed2006

Sporadic intragenic inversion of the mitochondrial DNA MTND1 gene causing fatal infantile lactic acidosis.

Mutations of mitochondrial DNA (mtDNA) are an important cause of genetic disease, yet rarely present in the neonatal period. Here we report the clinical, biochemical, and molecular genetic findings of an infant who died at the age of 1 mo with marked biventricular hypertrophy, aortic coarctation, and severe lactic acidosis due to a previously described but unusual mtDNA mutation, a 7-bp intragenic inversion within the mitochondrial gene encoding ND1 protein of complex I (MTND1). In direct contrast to the previous case, an adult with exercise intolerance who only harbored the mutation in muscle, the MTND1 inversion in our patient was present at high levels in several tissues including the heart, muscle, liver, and cultured skin fibroblasts. There was no evidence of the mutation or respiratory complex I defect in a muscle biopsy from the patient's mother. Transmitochondrial cytoplasmic hybrids (cybrids) containing high mutant loads of the inversion expressed the biochemical defect but apparently normal levels of the assembled complex. Our report highlights the enormous phenotypic diversity that exists among pathogenic mtDNA mutations and reemphasizes the need for appropriate genetic counseling for families affected by mtDNA disease.

Acidosis, Lactic↗

PubMed2005

Multi-institutional development and utilization of a computer-assisted learning program for the pediatrics clerkship: the CLIPP Project.

Computer-assisted instruction (CAI) holds significant promise for meeting the current challenges of medical education by providing consistent and quality teaching materials regardless of training site. The Computer-assisted Learning in Pediatrics Project (CLIPP) was created over three years (2000-2003) to meet this potential through multi-institutional development of interactive Internet-based patient simulations that comprehensively teach the North American core pediatrics clerkship curriculum. Project development adhered to four objectives: (1) comprehensive coverage of the core curriculum; (2) uniform approach to CAI pedagogy; (3) multi-institutional development by educators; and (4) extensive evaluation by users. Pediatrics clerkship directors from 30 institutions worked in teams to develop a series of 31 patient case simulations. An iterative process of case content and pedagogy development, case authoring, peer review, and pilot-testing ensured that the needs of clerkship directors and medical students were met. Fifty medical schools in the United States and Canada are presently using CLIPP. More than 8,000 students have completed over 98,000 case sessions, with an average of 2,000 case sessions completed per week at this time. Each CLIPP case has been completed by more than 3,000 students. The current cost of CLIPP development is approximately $70 per student user, or $6 per case session. The project's success demonstrates that multi-institutional development and implementation of a peer-reviewed comprehensive CAI learning program by medical educators is feasible and provides a useful model for other organizations to develop similar programs. Although CAI development is both time-consuming and costly, the initial investment decreases significantly with broad use over time.

Adult↗

PubMed2004

Students assigned to community practices for their pediatric clerkship perform as well or better on written examinations as students assigned to academic medical centers.

BACKGROUND: Medical schools are increasingly using community practice sites (CPS) for clerkship training. PURPOSES: We compared the test performance of all students assigned to CPS with all students trained at an academic medical center (AMC) for their pediatric clerkship for the past 5 years. METHODS: Baseline comparability of both groups was established by the group mean scores on 1st and 2nd year medical school grade point average (GPA) and the United States Medical Licensing Examination (USMLE) Step 1 and Step 2. Performance outcome was compared by group mean scores on a written clerkship exam and the National Board of Medical Examiners Pediatric Subject Examination. RESULTS: There was no statistical difference between the two groups with regard to GPA or USMLE scores. Standardized test performance results: [table: see text] CONCLUSION: The CPS-trained students performed as well or better on standardized written tests compared with AMC-trained students. Community pediatric practices can provide a quality clerkship experience for junior medical students.

Academic Medical Centers↗

PubMed2003

Arterial-esophageal fistula: a complication of nasogastric tube placement after lumbar spine surgery: a case report.

STUDY DESIGN: A case of arterial-esophageal fistula related to nasogastric tube placement in a 13-year-old girl after surgical correction of her progressive congenital lumbar kyphosis is presented. OBJECTIVES: This case report illustrates the importance of early recognition of "sentinel" hematemesis before massive hemorrhage, as this may allow for timely surgical intervention to prevent fatal exsanguination. The proposed pathogenesis of the arterial-esophageal fistula in the reported patient is discussed. SUMMARY OF BACKGROUND DATA: Although arterial-esophageal fistula formation has been recognized as an unusual complication of prolonged nasogastric intubation, to the authors' knowledge, this is the only case that illustrates an association of this complication with short-term nasogastric tube placement. METHODS: A 13-year-old girl was evaluated for progressive congenital lumbar kyphosis. Failure of segmentation and an anterior bar at L4-L5 was diagnosed when the patient was 7 years of age. At that time, she showed 28 degrees of kyphosis from L3 to L5. Because of her cardiopulmonary status at the time, she was deemed not to be a candidate for a corrective surgical procedure and followed conservatively until the age of 13 years. At that time, her gibbus deformity was 56 degrees from L3 to L5. She had significant ventral sagittal imbalance, which in combination with her cardiopulmonary abnormalities created difficulty with ambulation. Her preoperative neurologic examination was within normal limits. The patient had an extensive history of congenital cyanotic cardiopulmonary disease. She was born with pulmonary atresia, right-sided aortic arch with mirror image branching, a large coronary sinus type atrial septal defect, and a large ventricular septal defect. She had history of multiple surgical procedures for correction of her congenital cardiopulmonary abnormalities. The patient underwent posterior L3 and L5 wedge pedicle reduction osteotomies with posterior instrumentation and fusion from L2 to S1 using pedicle screw segmental fixation. A nasogastric tube was placed after surgery. On postoperative day 7, profuse bleeding from the patient's mouth and nose developed, which subsequently ceased. Shortly afterward, she became hypotensive and tachycardic. Upper gastrointestinal endoscopy showed a large amount of blood in her stomach without an active source. Cardiac arrest then developed, and she could not be resuscitated. The autopsy findings were consistent with an arterial-esophageal fistula. RESULTS: In the reported patient, the anomalous aortic arch system provided direct contact between the aorta and the esophagus. Dense fibrous adhesions between the aorta and esophagus resulting from multiple previous thoracic surgeries also may have facilitated the development of the fistula by the nasogastric tube in this patient. CONCLUSIONS: Patients with congenital cardiac abnormalities frequently also have congenital spinal deformities. These patients may undergo spinal correction procedures requiring nasogastric intubation. Increased awareness of arterial-esophageal fistula among the spine surgery community may enhance early recognition and treatment of this potentially lethal condition.

Arteries↗

PubMed2003

Ninety-day mortality after shoulder arthroplasty.

Although mortality associated with knee and hip arthroplasty has been reported, there is no information about shoulder arthroplasty. The purpose of this study was to determine the incidence and risk factors associated with perioperative mortality after shoulder arthroplasty. Between 1970 and 2000, 2,953 patients underwent shoulder arthroplasty at our institution. A retrospective review identified all patients who died within 90 days of the procedure. The 90-day mortality incidence was 0.58% (17 of 2,953). Twelve hemiarthroplasties were performed for a pathologic fracture and one for rotator cuff arthropathy. Total shoulder arthroplasties were performed for the sequelae of trauma (2), rheumatoid arthritis (1), and avascular necrosis (1). Ninety-day mortality was closely associated with the underlying diagnosis. Perioperative mortality after shoulder arthroplasty for non-neoplastic conditions is low.

Aged↗

PubMed2003

Open ankle fractures in patients with diabetes mellitus.

Complications after surgical treatment of closed ankle fractures in patients with diabetes previously have been well documented. The purpose of this study was to evaluate the union rate, infection rate, and soft tissue complication rate in open ankle fractures in patients with diabetes. Between January 1, 1981 and December 31, 2000, 14 open ankle fractures in 13 patients with diabetes were treated. The mean followup was 19 months (range, 6-84 months). All patients were followed up until union, amputation, or for at least 6 months. Nine of 14 extremities (64%) had wound healing complications. Ultimately, five patients (six extremities; 42%) had below the knee amputation. Only three of 14 fractures in three patients healed without complications. Open ankle fractures in patients with diabetes are limb-threatening injuries with high amputation and infection rates despite contemporary techniques of open reduction and internal fixation, intravenous antibiotics, and emergent irrigation and debridement.

Adult↗