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Biomedical subjects

R A Cannon

Publications and source records attributed to R A Cannon.

At least 19 recordsLinked to original sources
PubMed1994

Glycogen storage disease in adults.

OBJECTIVE: To identify complications amenable to prevention in adults with glycogen storage disease (GSD) types Ia, Ib, and III and to determine the effect of the disease on social factors. DESIGN: Case series and clinical review. SETTING: Referral medical centers in the United States and Canada. PATIENTS: All patients with GSD-Ia (37 patients), GSD-Ib (5 patients), and GSD-III (9 patients) who were 18 years of age or older. MEASUREMENTS: Ultrasound or radiographic studies identified liver adenomas, nephrocalcinosis, or kidney stones. Radiographic studies identified osteopenia. Reports of the clinical examination, serum chemistry results, and social data were obtained. RESULTS: For patients with GSD-Ia, problems included short stature (90%), hepatomegaly (100%), hepatic adenomas (75%), anemia (81%), proteinuria or microalbuminuria (67%), kidney calcifications (65%), osteopenia or fractures or both (27%), increased alkaline phosphatase (61%) and gamma-glutamyltransferase (93%) activities, and increased serum cholesterol (76%) and triglyceride (100%) levels. Hyperuricemia was frequent (89%). Patients with GSD-Ib had severe recurrent bacterial infections and gingivitis. In patients with GSD-III, 67% (6 of 9) had increased creatinine kinase activity. Four of these patients had myopathy and cardiomyopathy. CONCLUSIONS: For GSD-Ia, hyperuricemia and pyelonephritis should be treated to prevent nephrocalcinosis and additional renal damage. For GSD-Ib, granulocyte-colony-stimulating factor may prevent bacterial infections. For GSD-III, more data are required to determine whether the myopathy and cardiomyopathy can be prevented. Most of the patients with GSD-I and GSD-III had 12 or more years of education and were either currently in school or employed.

Adult↗
PubMed1994

Effect of short-term infusion of recombinant human relaxin on blood pressure in the late-pregnant rhesus macaque (Macaca mulatta).

OBJECTIVE: To test a recombinant human relaxin preparation, developed for potential therapeutic application, for possible hypotensive actions in near-term pregnant rhesus monkeys. METHODS: Groups of four females received 1-hour intravenous infusions of 0, 0.1, or 2.0 mg recombinant human relaxin/kg on gestation day 147 (term = 165 days). Maternal heart rate, electrocardiogram, and diastolic, systolic, and mean arterial pressure; and fetal heart rate were monitored before, during, and after the infusion. After spontaneous delivery, physical, neurobehavioral, and physiologic examinations were conducted on the newborn. RESULTS: No effects of recombinant human relaxin were detected by statistical analysis or examination of data records. CONCLUSION: Intravenous infusion of up to 2.0 mg recombinant human relaxin/kg in conscious pregnant rhesus monkeys had no effect on maternal cardiovascular indices or fetal heart rate.

Animals↗
PubMed1993

Postprandial gastric motility in infants with gastroesophageal reflux and delayed gastric emptying.

Delayed gastric emptying of formula is observed in many infants with gastroesophageal reflux but the mechanisms responsible for this observation are not defined. Postprandial gastric motility was quantified using a perfused catheter placed into the distal stomach of five infants with gastroesophageal reflux and delayed gastric emptying of 99mTc-sulfur colloid-labeled formula. Five infants with reflux who exhibited normal emptying of formula served as the controls. Gastric motility indices were calculated for 60 min following a meal. Half the patients in each group were given metoclopramide following a 30-min recording period. In both groups, postprandial gastric motility was similar and characterized by minimal gastric contractions. Metoclopramide resulted in increased amplitude and duration of antral contractions, but no significant differences were noted between groups. The findings suggest that minimal delays in gastric emptying in infants with gastroesophageal reflux are not associated with significant alterations of postprandial gastric motility.

Bottle Feeding↗
PubMed1992

The role of expatriate advisers: effective teaching in Indonesian medical education.

The expatriate advisor or 'expert' working in Indonesian medical education will require a complex range of personal and professional qualities if he or she is to be effective. Personal qualities refer particularly to the nature of the relationships that are established. Professional qualities include expertise in the discipline as well as expertise in teaching and education more generally. None of the qualities identified in the study is simple or unidimensional. The qualities are complex and are also likely to vary among educators according to their own level of education and cross-cultural experience.

Attitude↗
PubMed1989

Development of methodology for recording colonic myoelectrical activity in the infant primate.

In order to study developmental aspects of colonic motility, we have developed a miniaturized electrophysiologic recording system for use in the infant primate rhesus (Macaca mulatta). Technical considerations including absence of rectal valves, decreased tissue thickness and small colonic diameter limit application of standard non-surgical recording methodology in this model. In-vivo testing with 4 different bipolar electrode probe configurations yielded satisfactory quality recordings only with silver chloride suction electrodes. Using this system, colonic slow waves and spike action potentials were studied in 6 infant primates (ages 1 to 7 months) both fasting and following a standard liquid meal of 10 cc/kg. In response to feeding, colonic spike potentials increased from 7.8 +/- 1.7 to 14.2 +/- 4.1 within 15 minutes (mean spikes +/- SEM/5 min interval). The observed response of the distal colon to a meal in this model is similar to the response reported in adult humans using intraluminal recording techniques. Utilizing the described methodology, the infant primate appears to be a suitable model for investigation of developmental aspects of gastrointestinal motility and electrophysiology. These techniques have important direct applications for investigation in the human infant.

Animals↗
PubMed1987

Orthotopic liver transplantation in patients with cystic fibrosis.

An 11-year-old boy who had cystic fibrosis underwent an orthotopic liver transplantation. His immediate postoperative course was not unusually complicated when compared with other liver transplant recipients. Transplantation did not correct abnormalities in the sweat test or the respiratory disease. Cholestasis due to obstruction of the recipient duct with tenacious bile was cleared by instilling N-acetylcysteine into the duct. On the 48th day after the transplantation, he died of an intraventricular and intracerebral hemorrhage caused by an Aspergillus brain abscess. We conclude that certain patients with cystic fibrosis may be appropriate candidates for liver transplantation, but their pre- and post-operative management may need to differ from other liver transplant recipients.

Aspergillosis↗
PubMed1986

3-Ketothiolase deficiency.

Two patients have been studied in whom the activity of the short chain-length-specific mitochondrial 3-ketothiolase was found to be deficient. Use of a range of 3-ketoacyl-CoA substrates showed that the other 3-ketothiolase isoenzymes were normal in each case. Both patients had episodic ketosis and metabolic acidosis. One patient had substantial evidence of damage to the central nervous system and two siblings who had died of the disease. The organic aciduria was characterized by the excretion of 2-methyl-3-hydroxybutyric acid and tiglyglycine. In one patient the organic aciduria was very subtle and was masked during the presence of ketosis, but it was clarified by an isoleucine load after recovery from ketosis.

3-Hydroxybutyric Acid↗
PubMed1985

Orthotopic liver transplantation in a patient with Amanita poisoning.

Orthotopic liver transplantation in patients with acute toxic hepatitis has not, to our knowledge, been reported. Our recent experience with orthotopic liver transplantation in a 3-year-old girl with acute hepatic failure secondary to Amanita poisoning is described. Aspects of Amanita toxin-induced pathophysiology pertinent to orthotopic liver transplantation are discussed. The results in this case provide important implications for patients with fulminant hepatic failure secondary to other hepatotoxic agents in whom liver transplantation is considered.

Acute Kidney Injury↗
PubMed1985

Gastrointestinal hemorrhage due to Mallory-Weiss syndrome in an infant.

A Mallory-Weiss tear of the gastroesophageal mucosa is reported as an unusual cause of upper gastrointestinal bleeding in a 3-week-old infant. The lesion, documented by endoscopy, appeared to follow hiccups. The bleeding responded to conservative medical management and resolved without surgical intervention.

Endoscopy↗
PubMed1985

Differential effect of botulinal toxin on esophageal motor function in infants.

The effect of Clostridium botulinum toxin on esophageal motor function was studied in four infants (ages 5-9 months) with confirmed infant botulism. Esophageal motility studies using a perfused catheter assembly were performed during the acute phase in all patients, and during the recovery phase in one patient. Motor function of the proximal esophagus and upper esophageal sphincter was abnormal in each, while motor function of the distal esophagus and lower esophageal sphincter was normal. Mean lower esophageal sphincter pressure was 24 mm Hg for the group (normal: 15-30 mm Hg). Sequential studies of proximal esophageal motility in one infant revealed a return of normal motor function which correlated with recovery of peripheral muscle strength and gag reflexes. C. botulinum toxin impairs proximal, but not distal, esophageal motor function in the infant botulism model. This effect appears to be consistent with the known action of the toxin on synaptic acetylcholine release and current concepts regarding distribution of cholinergic and noncholinergic neurotransmitter receptors in the esophagus.

Botulinum Toxins↗
PubMed1983

Biochemical and ultrasonic abnormalities of the pancreas in anorexia nervosa.

Seven of 10 patients with anorexia nervosa had ultrasonic and/or biochemical abnormalities of the pancreas. Seven patients had elevated amylase creatinine clearance ratios (greater than 4%), three patients had elevated serum amylase values (greater than 90 units/liter), and three patients had reduced echogenicity of the pancreas. There was no consistent association between presenting abdominal symptoms and abnormal ultrasonic and biochemical studies of the pancreas. After nutritional repletion, all studies reverted to normal. An eleventh patient, who was initially diagnosed as having anorexia nervosa but later found to have an astrocytoma of the medulla, had reduced echogenicity of the pancreas, suggesting malnutrition as the cause of these abnormal pancreatic studies. Pancreatic abnormalities due to protein-calorie malnutrition may be common in anorexia nervosa and must be differentiated from primary pancreatitis.

Adolescent↗
PubMed1983

Experience with home parenteral nutrition.

Twenty-nine patients underwent courses of home parenteral nutrition therapy ranging from 1.5 to 52 months (mean 14.5 months). The primary diagnoses responsible for the requirement of home parenteral nutrition were radiation enteritis in seven patients, short bowel syndrome secondary to resection in seven, Crohn's disease in two, malabsorption states in six, and other reasons in seven. Seventeen patients (57 percent) had at least one complication. Nine patients had intravenous catheter complications and nine had metabolic complications. Nine patients have died, 11 have been successfully weaned from home parenteral nutrition, and 9 continue to receive home parenteral nutrition. Home parenteral nutrition is useful in a variety of catastrophic clinical situations, including preparation for subsequent operative therapy, temporary malabsorption, and permanent disability of the gastrointestinal tract. Complications are frequent and may be life-threatening.

Adolescent↗
PubMed1982

Reversal of enterocolitis-associated combined immunodeficiency by plasma therapy.

Two 6-month-old male infants with diarrhea, malabsorption, and hypoproteinemia, who were initially diagnosed as having combined immunodeficiency syndrome, recovered with intensive plasma therapy. Prior to the onset of diarrhea, they had normal serum protein and lymphocyte values. Immunologic features of combined immunodeficiency included lymphopenia, diminished B and T cells, cutaneous anergy, low immunoglobulin levels, and poor lymphocyte proliferative responses in vitro. Prior to therapy, both children had rectal ulcerations by proctosigmoidoscopy, colitis by rectal biopsy, and moderate to severe intestinal villus abnormalities by small bowel biopsy; plasma cells were absent Both had generalized malabsorption of all nutrients. Both infants were given irradiated fresh-frozen plasma for one to two months at 11 to 20 ml/kg/day to replace intestinal protein losses. During this time, diarrhea slowed, biopsy morphology improved, and immunoglobulin levels and T-cell function became normal. After discontinuance of plasma therapy, normal immune function and a normal stool pattern with reversal of malabsorption continued. Since intensive plasma therapy may have contributed to the reversal of the immunodeficiency state, a trial of such therapy is recommended in similar patients.

B-Lymphocytes↗