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Biomedical subjects

J R Buck

Publications and source records attributed to J R Buck.

36 records · Page 2Linked to original sources
PubMed1987

The efficacy of computed tomography in evaluating abdominal injuries in children with major head trauma.

Physical examination may be unreliable in the evaluation of children with blunt abdominal trauma particularly in those with associated major head injuries. In the absence of obvious clinical signs or physical findings of intraabdominal injury, the usefulness of abdominal computed tomography in children is controversial. To test the efficacy of CT scans, a 12-month prospective study of computed tomography for the initial assessment of children with blunt abdominal trauma and major head injuries was carried out. Of 320 pediatric trauma admissions to our regional trauma center, 65 consecutive patients with Glasgow Coma Scores less than ten were managed with sequential head and abdominal computed tomography in the emergency room for (1) closed head injury and (2) suspected abdominal trauma. Fifteen patients (23%) were found to have significant intraabdominal injury. Only two required operative intervention. No patients died as a result of the abdominal injuries. In children with significant head trauma and suspected abdominal trauma, combined head and abdominal CT proved to be reliable.

Abdominal Injuries↗
PubMed1986

Hydroperoxide-dependent epoxidation of 3,4-dihydroxy-3,4-dihydrobenzo[a]anthracene by ram seminal vesicle microsomes and by hematin.

Addition of arachidonic acid to ram seminal vesicle microsomes oxidizes 3,4-dihydroxy-3,4-dihydrobenzo[a]anthracene (BA-3,4-diol) to five more polar products. Four of the products are identified by chromatographic and spectroscopic analysis as tetrahydrotetraols, which are solvolysis products of dihydrodiolepoxides. The fifth product is a 10-methyl ether formed by methanolysis of the anti-diolepoxide. Quantitation of the individual products indicates that anti-diolepoxides predominate over syn-diolepoxides by approximately 2:1. Identical product profiles are detected from the reaction of BA-3,4-diol with hematin and 13-hydroperoxy-octadecadienoic acid in the presence of Tween 20. No other products are detected in either system, which indicates that peroxyl radicals oxidize BA-3,4-diol exclusively by epoxidation of the 1,2-double bond. The stereochemical and regiochemical differences between oxidation of BA-3,4-diol by peroxyl radicals and cytochrome P-450 are dramatic and suggest that BA-3,4-diol is uniquely suited as a probe to quantitate peroxyl radical-dependent epoxidation in vitro and in vivo.

Animals↗
PubMed1985

A therapeutic trial of amniotic epithelial cell implantation in patients with lysosomal storage diseases.

To determine whether allografts of normal amniotic epithelium might provide a nonimmunogenic cellular source of exogenous lysosomal enzymes, subcutaneous implants of amniotic epithelium were performed in six children with clinically advanced storage diseases. The clinical and the biochemical status of each patient was observed for several weeks after amniotic epithelial cell implantation (AECI). Serial studies of blood samples from each patient in the post-AECI period did not demonstrate any increase in levels of deficient lysosomal hydrolase. In two patients, quantitative urinary excretion of substrate was also studied and did not show consistent alterations after AECI. No patient had objective improvement in clinical or neurodevelopmental status following AECI. Two patients died with progressive disease at 2 1/2 and 3 1/2 mo after AECI; no residual amniotic epithelium was found at postmortem examination. Four patients are alive with progressive disease at 6-14 mo after AECI. We conclude that allografts of normal human amnion do not provide sufficient replacement hydrolases for clinical or biochemical improvement in lysosomal storage diseases.

Amidohydrolases↗
PubMed1985

Life-threatening airway obstruction as a complication to the management of mediastinal masses in children.

Life-threatening airway obstruction from large mediastinal masses in children poses a difficult diagnostic and therapeutic dilemma, requiring the close coordination of a pediatric surgeon, anesthesiologist, radiologist, and oncologist. To focus on this problem, the anesthetic and surgical management of 50 consecutive children with mediastinal masses treated between 1978 and 1984 were reviewed. Thirty children presented with respiratory symptoms; nine had life-threatening respiratory compromise with dyspnea, orthopnea, and stridor. Thirteen of these symptomatic children had marked compression of the trachea and/or mainstem bronchi on radiographic studies. The tracheal cross-sectional area which was measured by computed tomography was decreased by 35% to 93% of the normal tracheal dimensions in these children. Nonresectable malignant neoplasms including lymphoma, Hodgkin's disease, rhabdomyosarcoma, and neuroblastoma were the eventual diagnoses in 10 of these patients. The other 3 patients were less than 4 years old and had benign lesions. General anesthesia was judged to be prohibitively risky in 5 of 13 patients. The diagnosis was established by node or needle biopsy under local anesthesia, and general anesthesia was deferred until the compromised airway was alleviated by radiation and chemotherapy. General anesthesia with endotracheal intubation was administered to 8 patients, 5 of whom developed total airway obstruction. Using a variety of maneuvers, ventilation was reestablished in all 5 patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Disease↗
PubMed1985

One-year experience in a regional pediatric trauma center.

During 1982, 267 children with life-threatening injuries were admitted to the Maryland Regional Pediatric Trauma Center at the Johns Hopkins Hospital. Seventy-three percent of patients arrived directly from the injury scene by helicopter (46%), ambulance (50%), or other (4%). Mechanisms of injury included motor vehicle accidents (MVA; 55%), falls (27%), assaults (8%), and sports and other injuries (10%). In 75% of MVA the child was a pedestrian. Fifty-one percent of injuries were single organ system, 29% involved two systems, and 20% involved three or more systems. Remarkably, the mortality of 6.7% was not affected by the number of organ systems involved, but was directly related to the presence or absence of head injury. Fourteen of seventeen deaths resulted from head injury. Eighty percent of documented liver and spleen injuries were managed nonoperatively. This nonoperative plan of management simplified the optimal treatment of head injury. The high frequency of head injury has mandated a more aggressive approach to the management of brain trauma including intracranial monitoring to facilitate control of cerebral edema. Our data demonstrate that an excellent quality of life may be anticipated even in children with severe head injury.

Adolescent↗
PubMed1984

Neonatal necrotizing enterocolitis: an update.

We reviewed 91 cases of neonatal necrotizing enterocolitis (NNEC), which continues to be a devastating disease occurring in 2% to 4% of all newborn intensive care unit admissions. Onset now occurs in older infants (11.9 days). The morbidity is significant (22%), with strictures (8%) and recurrences (8%) the primary problems. Recurrences are more likely to require surgical intervention and result in a high mortality. Early diagnosis of necrotic bowel before perforation, peritoneal contamination, and sepsis is difficult and contributes to the still high, but improved, overall mortality of 36%.

Enterocolitis, Pseudomembranous↗
PubMed1983

Open lung biopsy in the immunocompromised pediatric patient.

Rapidly progressive pulmonary distress occurs as a secondary complication in immunocompromised pediatric patients. These patients usually develop a pattern of diffuse alveolar and/or interstitial infiltrates on chest x-ray and pursue a rapidly downhill course despite intensive respiratory support with the use of multiple and varied antimicrobial regimens. These patients are subjected to diagnostic open lung biopsies to establish a diagnosis. The diagnostic value of open lung biopsy and its current impact on therapy is not clearly established. This retrospective study attempts to determine the impact of open lung biopsy on diagnosis and therapeutic outcome. Between November, 1974, and October, 1982, 40 diagnostic open lung biopsies were performed on immunocompromised patients with clinically progressive respiratory disease. Adequate follow-up for complete evaluation was possible in 34 of these patients. Most of these patients had hematologic malignancies and all were on chemotherapeutic drugs at time of open lung biopsy. Open lung biopsy was considered helpful, ie, resulted in a change in antimicrobial therapy or substantiated preoperative therapy, in 17 of our 34 patients (50%). A "treatable" condition, amenable to antimicrobial therapy, was diagnosed in 16 of our patients (47%). Pneumocystis carinii pneumonitis (PCP) was the most common diagnosis in 11 (69%) of our "treatable" patients. The remaining five "treatable" patients had sarcoidosis (1), histiocytosis X (1), bacterial pneumonitis (1) and fungal pneumonitis (2). No diagnosis was achieved by open lung biopsy in ten (30%) of our patients. There were two complications attributable to open lung biopsy (6%), including one death. All PCP patients treated with trimethoprim sulfamethoxazole (T/S) survived.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1983

New techniques in the diagnosis and operative management of Siamese twins.

New techniques of 2-D sonography and radionucleotide Disofenin scanning allowed noninvasive evaluation of thoracoomphalopagus Siamese twins and successful separation at four days of age. Twin girls joined at the lower sternum and upper abdomen and weighing 15 lbs, were transferred at five hours of age after caesarian-section delivery. Scout films revealed high intestinal obstruction in twin A. 2-D sonography showed separate and normal hearts with different rates and attached pericardial sacs. Labeled Disofenin given intravenously to twin A was excreted exclusively in her gallbladder and bile ducts; vice versa for twin B. Because operation was necessary to correct jejunal atresia in twin A, further growth and development was not an option and the parents agreed to total correction. Sternal and pericardial separation and division of common midline-liver was followed by primary diaphragmatic defect repair and Dacron-cloth fascial reconstruction to upper abdominal wall and complete soft-tissue and skin closure in a ten-hour operation. Segmental jejunal resection and anastomosis with gastrostomy was added in baby A. The new tests greatly simplified definition of the anatomical relationships and implemented rapid correction in these newborn conjoint twins.

Electrocardiography↗
PubMed1982

Rational use of antibiotics for perforated appendicitis in childhood.

Gangrenous and perforated appendicitis was reviewed in 300 pediatric patients. Those with only gangrene generally had a benign course regardless of whether antibiotic therapy was used. However, patients with local perforation or generalized peritonitis had a high incidence of infective complications if they were not treated with antibiotics. Children treated with ampicillin, gentamicin, and clindamycin had markedly fewer wound infections and abscesses and were able to tolerate a diet and go home sooner than those receiving ampicillin and/or gentamicin.

Abscess↗
PubMed1982

Treatment of segmental tracheomalacia and bronchomalacia by implantation of an airway splint.

A silastic reinforced marlex mesh splint was inserted surgically to support a collapsing airway in 3 children with tracheomalacia and 1 with bronchomalacia. The operation was well tolerated and no complications occurred. The splint successfully eliminated symptoms of airway collapse in all children. Its effect on airway growth is not yet certain. This method is applicable to patients with tracheomalacia in whom vascular suspension does not eliminate collapse and for those with bronchomalacia in whom pulmonary resection might otherwise be necessary.

Bronchi↗
PubMed1982

THe significance of fever following operations in children.

To determine the incidence and clinical significance of early postoperative fever, all children (n = 256) undergoing surgery in the main operating theatres during a 4 wk period were studied. Admission and operating room data were reviewed and the clinical record was monitored at 12 hourly intervals for the first 3 postoperative days. The patients were followed for 1 mo for the development of recognizable complications. Seventy-three children (28.5%) developed fever greater than 38 degrees C but in only four (1.6%) did this represent a septic process. Physical examination led to the proper diagnosis in all. Risk factors that correlated statistically with postoperative fever were operation of greater than 2 hr (p less than .001), intraoperative transfusion (p less than .001), preexisting infection (p less than .01) and the use of preoperative antibiotics (p less than .001). Anatomic site of operation, age and sex were not significant factors. We conclude that many factors other than infection are responsible for post-operative fever. Further, only a very small proportion of children with early postoperative fever develop significant septic complications. In the assessment of postoperative fever a protocol which indiscriminately includes lab investigations and X-rays is costly and usually not diagnostic. Laboratory tests are indicated mainly to confirm diagnoses suspected by clinical evaluation.

Adolescent↗
PubMed1980

Cost evaluation of alternative pharmaceutical tableting processes by simulation.

A simulation model and a subsequent computer program were developed as experimentation methods for evaluating tableting processes with respect to cost. These methods also allow estimation of the various times involved in a tableting operation (e.g., the processing time). The model was programmed in FORTRAN using the GASP IV simulation language. After verification of the program, experiments were run that involved comparing different levels of specific input variables to determine which variable had an effect on the cost-time relationships of a particular processing method. Among the possible input variables chosen for evaluation were the drying method, the type of tableting machine, the batch size, the labor rate, and the operation of the equipment in the process. An analysis of variance was made, and three separate regression equations were developed that described the relationship between the input variables and the dependent variables of processing cost and time. Graphs were developed from the regression equations by manipulating them through series of different independent variables. These graphs then were used in determining minimum costs and times, breakeven points, and rates of change, as well as in simple evaluation of processes through graphic representation. By using the simulation program to run experiments and then by analyzing them, results can be obtained to help in making intelligent decisions about the cost-time relationships of a particular tableting procedure before it is implemented.

Chemistry, Pharmaceutical↗
PubMed1977

Fiberoptic transillumination: a new tool for the pediatric surgeon.

Transillumination (TI) is a safe and reliable technique for evaluating masses or the presence of free air in the thorax or abdomen. TI can also be of help in the accurate placement of catheters or needles in the chest, abdomen, bladder, or vessels. Its use in several hundred cases has been documented by this report.

Emphysema↗
PubMedDate not supplied

Multipurpose central venous access in the immunocompromised pediatric patient.

During a 21-month period, 50 consecutive pediatric oncology patients undergoing bone marrow transplantation and/or cytoreductive chemotherapy had 61 silastic central venous catheters placed to facilitate their therapy. All catheters were used for medications, routine blood sampling, and transfusions, with 45% also used for hyperalimentation and 57% used for bone marrow transplantation. Catheters were utilized during both inpatient and outpatient therapy periods. Total catheter days numbered 8455, an average of 139 days per catheter. Forty-seven catheters (77%) were removed electively or were in place at time of patient death. Seven were removed for mechanical complications (1/1409 catheter days). Four additional episodes of presumed catheter sepsis were managed with antibiotics and did not require catheter removal (40% of septic episodes). One catheter is still in place after 585 days. Complication rates were not influenced by this multiple use protocol. With standardized catheter care and surveillance, multipurpose, long-term central venous access can be safely utilized in the immunosuppressed pediatric patient.

Adolescent↗