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Biomedical subjects

B M Newman

Publications and source records attributed to B M Newman.

At least 37 records · Page 2Linked to original sources
PubMed1986

Advances in the management of infected urachal cysts.

Persistent urachal remnants are uncommon congenital anomalies. Unless an umbilical fistula exists, infection may be the first indication of this abnormality. Five children received initial treatment for this problem at the Children's Hospital of Buffalo during a 20-year period, 1964 to 1984, and a sixth was seen secondarily. There were four boys and two girls; their ages ranged from 8 months to 9 years. Lower abdominal mass with fever and local tenderness were the most common presenting signs. Ultrasound was the most accurate study, correctly diagnosing the cyst in both patients so examined. Incision and drainage alone was performed in one patient. The other five were managed with antibiotic therapy and complete excision as the primary procedure. Cultures were obtained in five patients and were positive in four, growing Staphylococcus aureus in three and Escherichia coli in one. Significant genitourinary abnormalities were discovered in four of the five patients evaluated. It is concluded that the previously recommended therapy of incision and drainage followed by delayed resection was developed in the preantibiotic era to minimize the mortality from sepsis and the morbidity from recurrence. Our experience indicates that the use of appropriate antibiotics followed promptly by complete cyst excision as a primary procedure is both possible and safe in most cases. Furthermore, the large number of associated genitourinary abnormalities suggests that a complete work-up for these conditions should be performed.

Bacterial Infections↗
PubMed1986

Computed tomography of traumatic lung cyst: case report.

Blunt trauma to the chest may result in the formation of a traumatic lung cyst. The lesion itself is innocuous and requires no special treatment. Though it is important that traumatic lung cyst not be mistaken for a more serious complication of trauma requiring aggressive management, this distinction may be difficult to make on plain chest radiographs. However, in the setting of blunt chest trauma, the computed tomography appearance of a thin-walled cystic cavity completely surrounded by lung parenchyma is diagnostic of traumatic lung cyst.

Adolescent↗
PubMed1986

Percutaneous central venous catheterization in children: first line choice for venous access.

Percutaneous central venous (CV) catheters using the jugular and subclavian veins have been widely used for hemodynamic monitoring and for venous access in difficult clinical situations. However, peripheral venous cutdowns (PVC) still remain the primary mode of short-term venous access in children. To evaluate percutaneous CV line insertion as a routine procedure, a prospective study of 115 patients (75 CV and 40 PVC) was performed. Ages ranged from 1 day to 17 years; age and weight were similar in both groups. Eighty-three CV lines were attempted, with a success rate of 93%, while 82% of 49 PVC insertions were successful. Complications occurred in 11 (14%) patients with CV access and 31 (78%) with PVC lines. In the latter group, poor flow was a problem in 65%, infiltration in 37.5%, and phlebitis in 27.5%. In the CV group, arterial puncture occurred during insertion in 2 (3%) patients with no adverse sequelae, catheter slippage occurred in 4 (5%), and poor flow in 2 (3%). A large majority (79.2%) of CV lines functioned successfully until no longer needed, as compared with 15% of PVC catheters. The latter were removed before completion of treatment because of poor flow (40%), phlebitis (20%), or catheter problems (10%). Catheter sepsis was documented in only one CV line. Two cutdowns had major local infections. The average catheter longevity was 10.2 days for CV lines, 4.1 days for PVC.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1986

Pediatric trauma associated with all-terrain vehicles.

The frequency of injuries secondary to use of all-terrain vehicles (ATV) is increasing at an alarming rate, and these injuries are usually multiple and severe. Between January 1, 1983, and February 28, 1985, 415 pediatric patients were admitted to the University of Virginia Hospital for care of injuries secondary to trauma; 66 of these patients required intensive care. Of the 415 patients, 12 were injured secondary to ATV use, and four of these required intensive care. The average age was 12 years (range 2 to 16 years), and the average hospital stay was 20 days. Injuries included five closed head injuries, two associated with a basilar skull fracture requiring intracranial pressure monitoring; five long bone fractures, two requiring open reduction and internal fixation; two small bone fractures; two splenic ruptures; two liver lacerations, one of them requiring laparotomy; and one renal hematoma. One patient has required long-term rehabilitation for neurologic deficits. Physicians and the public should be aware of the injury potential of these vehicles and should advocate legislation promoting helmet laws and high safety standards for ATV users.

Abdominal Injuries↗
PubMed1986

Pancreaticobiliary factors in the modulation of small intestinal enterokinase in the rat.

Chronic pancreaticobiliary diversion was employed to study the modulation of enterokinase in the small intestine of adult rats. Diversion resulted in apparent trophic changes of the proximal bypassed portion of the intestinal mucosa. An almost complete loss of mucosal enterokinase activity in the proximal duodenum but no increase of enterokinase in the segments distal to reentry of the common duct was found in the pancreaticobiliary-diverted rats. The effect on the enterokinase activity in the proximal segment was specific in that no other brush-border enzymes measured in that segment were decreased. The decrease in enterokinase was partially prevented by dietary supplementation with pancreatic trypsinogen and completely avoided with the addition of a combination of bile acids and trypsinogen. Supplementation with bile acid alone did not preserve the enterokinase levels in the bypassed rats. The results suggested that trypsinogen is the primary factor responsible for modulating enterokinase levels in the proximal small intestine, with bile acids acting as a modifier.

Animals↗
PubMed1986

Enteral feedback control of pancreatic hypertrophy: the role of pancreatic biliary secretions.

Chronic diversion of pancreatic and biliary secretions away from the proximal small intestine resulted in rapid increases in pancreatic size and protein content in adult rats. The effect was detectable as early as 10 days postsurgery. Differential changes in pancreatic enzymes were evident after bypass. The concentration of trypsinogen remained stable while amylase concentrations showed a marked decrease. Total pancreatic trypsinogen content, however, was increased, while amylase content remained similar to controls. Feeding bypassed rats with chows containing various pancreatic and biliary supplements had no effect on the hyperplastic response of their pancreata. Trypsinogen and amylase levels in supplemented groups remained similar to the bypassed group fed nonsupplemented chow, with the exception of increases in trypsinogen concentration and content in the groups supplemented with bile and cotazyme plus bile acids. The adequacy of oral refeeding of pancreatic biliary components was supported by its effectiveness in restoring mucosal enterokinase activity and trypsin levels in segment 1. However, there was no correlation between tryptic activity in the contents of the bypassed segment and the eventual pancreatic weight. These results indicate that factors other than those supplemented in this study are required in maintaining the steady state of pancreatic growth in normal rats.

Ampulla of Vater↗
PubMed1986

Cholecystokinin: a factor responsible for the enteral feedback control of pancreatic hypertrophyphy.

Chronic diversion of pancreatic and biliary secretions away from the proximal small intestine results in pancreatic hypertrophy in adult rats. Serum levels of cholecystokinin (CCK) were measured in age-matched control and surgically diverted rats at various times after operation by a radioimmunoassay method that was specific for the sulfated form of CCK. The concentration of CCK was markedly increased in bypassed rats as compared with controls. The increases in circulating CCK in bypassed rats was substantiated by a bioassay method that measured physiologically active CCK. The degree of pancreatic hypertrophy and the increase in CCK levels both progressed with time up to 23 days after surgery. Linear regression analysis showed an apparent direct correlation between pancreatic weights and serum CCK levels (r = 0.99). Feeding bypassed rats with diets containing various pancreatic and biliary supplements did not abolish the hyperplastic response of their pancreata. However, feeding with diets supplemented with bile partially suppressed the increase in serum CCK levels, while a diet containing Cotazyme and bile completely suppressed this increase. The discrepancy between serum CCK levels and the degree of pancreatic hypertrophy in the supplemented bypassed rats was further demonstrated by the lack of correlation using linear regression analysis (r = 0.33). The observed pancreatic hypertrophy in the absence of high serum levels of CCK in the bypassed rats fed bile and Cotazyme supplements suggests that serum hypertrophic factors other than CCK may also be involved in the enteral feedback regulation of pancreatic growth.

Animals↗
PubMed1985

Prosthetic materials and muscle flaps in the repair of extensive diaphragmatic defects: an experimental study.

Relative merits of three methods of diaphragmatic hernia repair were evaluated in growing animals. Twenty-five puppies underwent laparotomy. In four controls, the left hemidiaphragm was incised and sutured primarily. In the remaining dogs, it was partially resected sparing the phrenic nerve. The defects were repaired in six with silastic sheeting, in eight with polytetrafluoroethylene (PTFE; trademark, Gore-Tex), and in seven with a thoracoabdominal muscle flap. Dogs were killed at 1, 4, and 7 months for gross and microscopic evaluation of the repair. Diaphragmatic function was evaluated by inspiratory force against a closed airway and by selective phrenic nerve stimulation (PNS). Serial fluoroscopy was used to evaluate diaphragmatic motion. Grossly the diaphragms in all groups showed compensatory growth. Microscopically the silastic was encapsulated without adherence, while PTFE showed tissue ingrowth. Maximal inspiratory force was equivalent in all groups but selective PNS revealed left-sided impairment in all experimental groups. Fluoroscopy showed paradoxical motion of the diaphragm in the muscle flap group for 1 to 2 months, and in the silastic repair group for 2 to 3 weeks, with near normal motion in the PTFE group for the entire postoperative period. These differences disappeared by 6 months. Prosthetic materials or muscle flaps are all safe for repair of large diaphragmatic hernias. Diaphragmatic growth occurs and the prosthesis remains in place. Physiologic impairment is minimal and not of clinical importance. Use of PTFE may be the preferred method as it develops better tissue incorporation and results in more normal diaphragmatic motion in the critical early postoperative period.

Animals↗
PubMed1983

The intercostal vein: an alternate route for central venous alimentation.

During the course of parenteral nutrition in infants, access to the central venous system may become limited due to thrombotic occlusion of the superior and inferior caval venous systems. When this problem arises, central venous access via the intercostal vein into the azygos system can provide a safe, relatively easy solution. A new technique utilizing this approach has been developed at our institution using silicone elastomer tubing joined with a Broviac catheter for long-term use. Thus far, six catheters have successfully been inserted with a mean duration of 52 days; one catheter was in place for as long as 110 days.

Azygos Vein↗
PubMed1983

The nonoperative management of pediatric hepatic trauma.

Although nonoperative therapy is well-accepted for renal and splenic injuries in children, this mode of treatment has not been widely advocated for children with blunt hepatic injury. Surgical repair or excision of the traumatized tissue has been the generally accepted standard of care. In the present series, 17 consecutive children between 2 and 13 years of age with liver trauma were managed by nonoperative means. Patients were carefully selected for treatment based on clinical criteria and initial computed tomography (CT) scan findings. The 17 patients with hepatic trauma identified by CT scan all responded to initial resuscitative measures. The children clinically remained stable and required only a limited number of transfusions. No immediate surgical intervention was necessary for isolated hepatic injuries. However, one patient required exploration due to an associated renal pedicle avulsion. One child required exploration on the fourth post-injury day because of a suspected infected hematoma. The remaining 15 injuries resolved without operation. Healing was documented on follow-up CT scans. The mean time required for resolution of the injury was 4 months. One child developed a late subhepatic hematoma which resolved without drainage. The progression of healing of hepatic parenchymal injuries was observed by serial CT scans. The liver injury progressed through stages of coalescence, resorption, and remodeling prior to final healing. Utilizing proper patient selection, many blunt liver injuries can be managed nonoperatively.

Adolescent↗
PubMed1980

Effect of dextran and ammonium sulphate on the reaction catalysed by a glucosyltransferase complex from Streptococcus mutans.

The highly aggregated proteins precipitated by (NH4)2SO4 from the culture fluid of three strains of Streptococcus mutans gradually released less aggregated glucosyltransferase activities - dextransucrase and mutansucrase - which catalysed the synthesis of water-soluble and insoluble glucans from sucrose. Mutansucrase was eluted from a column of Sepharose 6B before dextransucrase. This activity was lost during subsequent dialysis and gel filtration, but there was a corresponding increase in dextransucrase activity which catalysed the formation of soluble glucan when incubated with sucrose alone, and insoluble glucan when incubated with sucrose and 1.55 M-(NH4)2SO4. Relative rates of synthesis of soluble and insoluble glucan in the presence of 1.55 M-(MH4)2SO4 were dependent upon the enzyme concentration: high concentrations favoured insoluble glucan synthesis. Insoluble glucans synthesized by mutansucrase or by dextransucrase in the presence of 1.55 M-(NH4)2SO4 were more sensitive to hydrolysis by mutanase than by dextranse, but soluble glucans were more extensively hydrolysed by dextranase than by mutanase. Partially purified dextransucrase sedimented through glycerol density gradients as a single symmetrical peak with an apparent molecular weight in the range 100000 to 110000. In the presence of 1.55 M-(NH4)2SO4, part of the activity sedimented rapidly as a high molecular weight aggregate. The results strongly suggest that soluble and insoluble glucans are synthesized by interconvertible forms of the same glucosyltransferase. The aggregated form, mutansucrase, preferentially catalyses (1 leads to 3)-alpha bond formation but dissociates during gel filtration to the dextransucrase form which catalyses (1 leads to 6)-alpha bond formation.

Ammonium Sulfate↗
PubMed1980

Biochemical and genetic characterization of nirB mutants of Escherichia coli K 12 pleiotropically defective in nitrite and sulphite reduction.

Mutants of Escherichia coli K12 defective in the nirB gene lack NADH-dependent nitrite reductase activity and reduce nitrite slowly during anaerobic growth. With one exception these mutants require cysteine for growth. Cytochrome C552 synthesis and the assimilation of ammonia are unaffected by the nirB mutation. The defective gene is located between the crp and aroB genes at minute 73 on the E. coli chromosome. Mapping and reversion studies indicate the nirB is identical to the previously described cysG gene. It is suggested that the product of the cysG+ (nirB+)¿gene is an enzyme required for the synthesis of sirohaem, a prosthetic group of enzymes which catalyse the six-electron reduction of nitrite to ammonia and sulphite to sulphide.

Chromosome Mapping↗
PubMed1978

The chromosomal location and pleiotropic effects of mutations of the nirA+ gene of Escherichia coli K12: the essential role of nirA+ in nitrite reduction and in other anaerobic redox reactions.

Cytochrome c552, which has been implicated as an electron carrier for nitrite reduction by Escherichia coli, has been separated from NADH-nitrite oxidoreductase activity. The cytochrome is therefore not required for the reduction of nitrite by NADH in vitro. Nevertheless, some mutants which were selected by their inability to use nitrite as a nitrogen source during anaerobic growth synthesize neither NADH-nitrite oxidoreductase nor cytochrome c552. The defects in these mutants are due to mutations in a single gene, nirA, which is located at about minute 29 on the recalibrated linkage map. Experiments with an F' plasmid which carries a nirA+ allele established that nirA+ is dominant to the defective allele. Other mutants, defective in nitrate reductase activity because of mutations in the chlA or chlB genes, synthesized nitrite reductase and cytochrome c552 in the absence of nitrate or nitrite. A mutant with a defective fnr gene was also NirA- and, conversely, nirA mutants were Fnr-. In a series of transduction experiments, attempts to separate the nirA and fnr defects were unsuccessful. Furthermore, no complementation was observed when an F' plasmid carrying a defective nirA allele was transferred into the fnr strain. It is concluded that the fnr gene described by Lambden & Guest (1976) is identical to the nirA gene and that its product affects the synthesis or assembly of a variety of anaerobic redox enzymes which include nitrite reductase, cytochrome c552, nitrate reductase, fumarate reductase and formate hydrogenlyase.

Chromosome Mapping↗
PubMed1978

The concept of identity: research and theory.

The concept of identity is one of the few themes of psychosocial theory that has been researched directly. The dichotomy between identity achievement and role diffusion can be more accurately understood as two potential statuses among a number of resolutions to the identity crisis. Identity status appears to be related to significant childrearing experiences, particularly to dimensions of warmth, limit setting, values of autonomy, and achievement orientation. The pattern of identity achievement is different for males and females. Successful achievement of identity reflects different parental child-rearing practices for males and females.

Achievement↗