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Biomedical subjects

B M Potter

Publications and source records attributed to B M Potter.

At least 19 recordsLinked to original sources
PubMed1992

Posttraumatic shock in children: CT findings associated with hemodynamic instability.

Twenty-seven of 1,018 children evaluated with contrast material-enhanced computed tomography (CT) after blunt trauma demonstrated a characteristic hypoperfusion complex. This complex was usually seen in young children (median age, 2 years). CT findings in all 27 patients included a dilated, fluid-filled bowel and abnormally intense enhancement of the bowel wall, mesentery, kidneys, aorta, and inferior vena cava. Twenty-four percent of all children with a Trauma Score of 10 or less and 20% with a Glasgow Coma Score of 6 or less had the hypoperfusion complex. All 27 patients had a normal blood pressure immediately before CT, but five (19%) became hypotensive within 10 minutes of intravenous contrast material administration. Twenty-three children (85%) died. Of 16 children who survived 24 hours, four (25%) developed renal insufficiency. The intense multiorgan enhancement pattern seen in the hypoperfusion complex indicates tenuous hemodynamic stability. Recognition that the constellation of CT findings is due to hypovolemic shock and not to injured viscera helps avoid unnecessary laparotomy.

Abdominal Injuries↗
PubMed1991

Infant rats depleted of brain dopamine as neonates exhibit normal independent ingestion.

Weanling or adult rats that have sustained near-total depletions of striatal dopamine (DA) on postnatal Day 3 do not exhibit the severe ingestive deficits seen in comparably depleted adults. The present experiments demonstrated that these animals are capable of ingesting independently, via an intraoral cannula, as early as three days after the depletion. Both activational and ingestive responses to maternal deprivation and intracellular dehydration were virtually identical to the responses of control pups. However, these responses may not be entirely dopaminergically mediated at Day 6 since administration of haloperidol failed to attenuate these behaviors in normal pups. When tested on Day 12, DA-depleted pups continued to exhibit normal ingestive and activational behaviors, despite the fact that haloperidol now suppressed these behaviors in both groups of 12-day-old pups. These findings demonstrate that there is a developmental progression of dopaminergic involvement in the control of independent ingestion and the associated activational responses, yet a near-total depletion of striatal DA is not sufficient to impair the expression of these behaviors.

Age Factors↗
PubMed1989

Food intake of rats depleted of dopamine as neonates is impaired by inhibition of catecholamine biosynthesis.

The food intake of rats depleted of brain dopamine (DA) as neonates was markedly reduced by doses of the catecholamine synthesis inhibitor. alpha-methyl-p-tyrosine (AMT), that had little effect on control animals. In contrast, rats depleted of DA as neonates were subsensitive to doses of the DA antagonist, haloperidol, that greatly inhibited food intake in controls. Unexpectedly, low doses of haloperidol potentiated the effects of AMT in both control and DA-depleted animals. These results suggest that activity within residual DA neurons may remain important for the expression of ingestive behavior in rats depleted of DA as neonates although the precise mechanisms may differ from those operating in normal animals.

Animals↗
PubMed1989

Renovascular hypertension in children: current concepts in evaluation and treatment.

Since 1981, we have evaluated and treated 22 children with renovascular hypertension (RVH). Seventeen patients had stenosis of their native renal arteries, and five had stenosis of the artery in a transplanted kidney. RVH was caused by fibromuscular dysplasia in 13 patients, by trauma in 2 patients, and by arteritis in 2 patients. Among the patients who had transplanted kidneys, three had technical causes for stenosis and two had stenosis due to rejection. The disease was unilateral in 10 patients, bilateral in 5, and present in a solitary kidney in 7, including the five renal transplants. Diagnostic studies that strongly suggested the presence of renovascular disease were an initial diastolic blood pressure greater than 100 mm Hg, an elevated peripheral vein renin activity level, and an abnormal renal scan if the patient's hypertension was being controlled with an angiotensin-converting enzyme inhibitor (ACEI). Only the renal arteriogram was 100% accurate in confirming the presence of RVH. Percutaneous angiographic correction was attempted in 13 patients and resulted in lasting improvement of the hypertension in five (38%). Surgical revascularization was attempted in 17 children, including the 8 with failed angioplasty, with improvement or cure of the hypertension in 15 patients (88%). Combining percutaneous transluminal angioplasty (PTA) and surgical results gave 20 of 22 patients (91%) with cure or improvement of their hypertension. Four of 27 affected kidneys (15%) could not be revascularized and were removed. We conclude from this series of patients that despite improvements in noninvasive studies, renal arteriogram remains the only study that is 100% accurate in evaluating children for RVH.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1988

Hematuria. A marker of abdominal injury in children after blunt trauma.

The clinical significance of hematuria after blunt trauma was studied in 378 consecutive children evaluated by computed tomography (CT) of the abdomen. Clinical and demographic data, as well as indications for CT (such as hematuria, abdominal tenderness, distention, contusions, and abrasions) were recorded prospectively at the time of CT examination. Hematuria was present in 256 children (68%). Of these, 168 (66%) had microscopic blood (greater than or equal to 10 RBC/HPF), 52 (20%) had a positive dip-stick (less than 10 RBC/HPF), and 36 (14%) had gross hematuria. Both the presence and increasing amount of blood in the urine were associated with significantly higher risk for abdominal injury, multiple organ trauma, and renal injury. Yet when asymptomatic hematuria was the only indication for CT examination, the risk of any abdominal injury was negligible (0 of 41 patients). The presence and severity of hematuria can be useful markers of underlying abdominal injury only in association with other suggestive clinical signs and symptoms. Asymptomatic hematuria is a low-yield indication for abdominal CT in children with blunt abdominal trauma.

Abdominal Injuries↗
PubMed1988

The role of computed tomography in blunt abdominal trauma in children.

This study was performed in order to test the hypothesis that abdominal computed tomography (CT) can assist in the decision to perform laparotomy in children following blunt trauma to the abdomen. Three hundred forty children with blunt abdominal trauma underwent evaluation with CT. Abdominal injuries were detected in 84 children (25%). These included: 75 injuries to solid viscera in 60 patients (30 splenic, 29 hepatic, 13 renal, and three pancreatic); four injuries to hollow viscera (three small bowel transections, and one rupture of the urinary bladder); and 23 skeletal injuries (21 fractures of the pelvis, and two lumbar spine subluxations). Injury to solid viscera was categorized as minor in 32 (43%), moderate in 18 (24%), or severe in 25 (33%) according to an assessment of the percentage of parenchyma involved. Hemoperitoneum was detected in 42 patients, and characterized as small in 18 (43%), moderate in nine (21%), and large in 15 (36%). CT was useful in establishing the location and extent of injuries, and in detecting the presence of blood or air in the peritoneal cavity. However, the extent of injury to solid viscera detected on CT did not correlate with the need for laparotomy. Of 46 moderate to severe anatomic injuries of the liver, spleen or kidney, only five (9%) required surgical intervention because of persistent bleeding or infection. Although laparotomy occurred more frequently in the presence of a large hemoperitoneum, only 6/24 (25%) with moderate to large hemoperitoneum required surgical exploration. This analysis confirms the usefulness of CT for detection of location and extent of injury in pediatric blunt abdominal trauma.(ABSTRACT TRUNCATED AT 250 WORDS)

Abdominal Injuries↗
PubMed1987

Hepatic and splenic injury in children: role of CT in the decision for laparotomy.

Clinical and radiographic records of 274 children who were examined with abdominal computed tomography (CT) after blunt abdominal trauma were retrospectively evaluated to test the hypothesis that CT can assist in decisions to perform laparotomy in children with hepatic or splenic injury. CT demonstrated parenchymal injuries in 36 patients (13%) or 20 livers and 21 spleens. Injury to these organs was categorized as minor (39%), moderate (39%), and severe (21%) according to an assessment of the percentage of parenchymal involvement. Hemoperitoneum was detected in 27 of 36 patients (75%). One of 13 (4.7%) with a moderate to large splenic injury underwent splenorrhaphy because of persistent bleeding. One of 12 (5%) with a moderate to large hepatic injury required late operative intervention due to a large necrotic segment. Both children had a large amount of peritoneal fluid. Two of 16 patients (13%) with moderate to large hemoperitoneum required surgery for liver or splenic injury. The decision for laparotomy should not be based on the extent of injury as shown at CT but on the physiologic condition of the child.

Abdominal Injuries↗
PubMed1986

A comparative evaluation of rare earth screen-film systems. Free-response operating characteristic analysis and anatomic criteria analysis.

Diagnostic accuracy was evaluated in a signal detection experiment that used low-contrast acute lesions in a living dog model. At the high levels of certainty normally used by radiologists, rare earth screen-film systems provided accuracy comparable to that of a reference calcium tungstate screen-film system. Additionally subjective image quality evaluation for a given imaging task (clinical pediatric anterior-posterior chest films) based on visualization of anatomic landmarks and physical parameters has been conducted for several rare earth and one calcium tungstate screen-film system. The correspondence of subjective physical ranking with physical and psychophysical measurements was investigated. Evaluating the visualization of anatomic parameters can provide a clear and objective distinction among systems with comparable physical and psychophysical properties.

Animals↗
PubMed1986

A comparative evaluation of rare-earth screen-film systems. System speed, contrast, sensitometry, RMS noise, square-wave response function, and contrast-dose-detail analysis.

We evaluated the physical characteristics and contrast-dose-detail performance of 11 rare-earth and three calcium tungstate screen-film systems. Measurements included system speed, contrast, sensitometry, RMS noise, square-wave response function, and contrast-dose-detail analysis. The major differences in physical characteristics among systems were system speed and RMS noise. Square-wave response differences were more subtle. For contrast-dose-detail analysis, the rare-earth screen-film systems and the calcium tungstate system responses were significant over a limited subject contrast range as a function of detail diameter. Relative dose efficiency in the noise-limited region is a function of the properties of the screen only and is independent of the film.

Calcium Compounds↗
PubMed1983

Reconstruction of the renal artery after unsuccessful percutaneous transluminal angioplasty in children.

The use of percutaneous transluminal angioplasty as the primary treatment of renovascular stenosis in adults has recently been described. Previously, only three children have been reported to have undergone transluminal angioplasty for stenosis of the renal artery and hypertension. At our hospital, transluminal angioplasty was attempted in four children with renal artery stenosis; one attempt was successful and three were unsuccessful. The three patients who required surgical repair of the renal artery after unsuccessful transluminal angioplasty have been described in detail. The histopathology of the stenotic vessels is also discussed. Based on the analysis of the three children, certain criteria have been derived to select pediatric patients with renovascular hypertension either for attempted transluminal angioplasty or for primary surgical revascularization.

Angioplasty, Balloon↗
PubMed1983

Partial splenic ablation in preparation for renal transplantation in children.

Patients with end-stage renal disease who develop hypersplenism, patients with mild neutropenia, and those patients whose WBC fails to increase in response to cortisol administration will develop significant neutropenia following transplantation with routine doses of azathioprine. This "intolerance" of azathioprine mandates a reduction in the dose of azathioprine often resulting in allograft rejection. Splenectomy will prevent azathioprine-induced neutropenia, but the hazards of splenectomy in these immunosuppressed patients have led to attempts to salvage at least part of the spleen. Partial splenic ablation by embolization has been utilized in adults prior to transplantation to prevent azathioprine-induced neutropenia while preserving the spleen's protective mechanisms against infection. Eight children in our series of transplant candidates required a reduction of splenic function to prevent azathioprine induced neutropenia. One child had a functioning renal allograft but had recurrent neutropenia limiting the azathioprine dose. Partial splenic embolization was attempted in four children and was initially successful in two. Both patients later developed recurrent neutropenia and needed partial splenectomy. The two patients in whom partial splenic embolization was unsuccessful and five further patients in whom embolization was not attempted also underwent partial splenectomy. Approximately 75% to 80% of the spleen was resected. Six children have since undergone renal transplantation and one child had a transplant with chronic rejection at the time of partial splenectomy. Routine doses of azathioprine have been used in these children with no episodes of neutropenia or sepsis observed. We recommend partial splenectomy in those children requiring renal transplantation who are at risk for development of azathioprine induced neutropenia.

Azathioprine↗
PubMed1978

Portal decompression in infants and children with the interposition mesocaval shunt.

The mesocaval graft for portal decompression is applicable in infants and children with portal hypertension secondary to extrahepatic or intrahepatic causes. It is recommended in patients in whom extensive previous surgery in the portahepatis (Kasai procedure) would make dissection of the portal vein difficult and endanger the integrity of the functioning biliary conduit. It can be performed in patients who have had previous splenectomy or in whom portacaval or splenorenal shunts have failed. Autogenous jugular vein is favored for creation of the shunt.

Adult↗