Resolution improvements in in vivo 1H NMR spectra with increased magnetic field strength.

The measurement of cerebral metabolites using highly homologous localization techniques and similar shimming methods was performed in the human brain at 1.5 and 4 T as well as in the dog and rat brain at 9.4 T. In rat brain, improved resolution was achieved by shimming all first- and second-order shim coils using a fully adiabatic FASTMAP sequence. The spectra showed a clear improvement in spectral resolution for all metabolite resonances with increased field strength. Changes in cerebral glutamine content were clearly observed at 4 T compared to 1.5 T in patients with hepatic encephalopathy. At 9.4 T, glutamine H4 at 2.46 ppm was fully resolved from glutamate H4 at 2.37 ppm, as was the potential resonance from gamma-amino-butyric acid at 2.30 ppm and N-acetyl-aspartyl-glutamate at 2.05 ppm. Singlet linewidths were found to be as low as 6 Hz (0.015 ppm) at 9.4 T, indicating a substantial decrease in ppm linewidth with field strength. Furthermore, the methylene peak of creatine was partially resolved from phosphocreatine, indicating a close to 1:1 relationship in gray matter. We conclude that increasing the magnetic field strength increases spectral resolution also for 1H NMR, which can lead to more than linear sensitivity gains.

Cystic fibrosis-associated colitis and fibrosing colonopathy.

OBJECTIVE: To describe our experience with cystic fibrosis (CF)-associated colitis and fibrosing colonopathy, and to assess treatment strategies. STUDY DESIGN: We reviewed hospital charts and autopsy reports of all University of Minnesota patients with CF between 1975 and August 1994. We identified six patients with colonopathy and compared them with a cohort of 79 patients with CF in the same age range and seen during the same period. RESULTS: All patients with colonopathy had bloody diarrhea; five of the six had abdominal pain. Stool frequency and related symptoms distinguished the patients with colonopathy from the cohort population. All took a higher median dose of pancreatic enzymes than the cohort population during the 3 months preceding the onset of symptoms (p < 0.002). For all six patients, barium studies revealed loss of haustration, and shortening and diffuse narrowing of the colonic lumen with relative rectal sparing. The distal ileal mucosa was irregular in four patients. A histopathologic study reveal fibrosis of the submucosa or lamina propria, and focal acute cryptitis in all six patients. Other features included ascites (2/6) and nodular regenerative hyperplasia of the liver (1/6). One patient continues to have symptoms, three had subtotal colectomy, and the condition of two improved after a regimen including a low-fat diet, withholding of pancreatic enzymes, and supplemental parenteral nutrition was initiated. CONCLUSIONS: Fibrosing colonopathy represents a newly recognized gastrointestinal complication of cystic fibrosis. Affected persons have taken larger doses of pancreatic enzymes than similar patients with cystic fibrosis, and have bloody diarrhea. We developed a medical protocol that may avoid surgical resection of the colon in some of these patients.

Increased dietary branched-chain amino acids do not improve growth in developing rats with chronic biliary obstruction.

We studied dietary branched-chain amino acid enrichment in cholestatic weanling rats. Growth was assessed with body weight, muscle weight and nitrogen balance. Systemic metabolic measurements that reflect liver function were evaluated, including plasma ammonia, albumin, amino acids, glucose, triglyceride and branched-chain ketoacids, as well as urinary carnitine excretion. Twenty-two rats underwent bile-duct ligation at 14 d of age. At weaning, 11 rats were fed a control diet and 11 an isoenergetic, isonitrogenous branched-chain amino acid-enriched diet for 3 wk, each with a sham-operated, pair-fed control. Body weights were similar in all four groups. Changes due to bile-duct ligation and not affected by the diet manipulation included lower plasma glucose, nitrogen balance and muscle weight, and higher triglyceride concentration, carnitine excretion and liver weight. Changes due to ligation that were normalized by dietary manipulation included plasma albumin, ammonia and total amino acid concentrations. The ratio of branched-chain to aromatic amino acids was decreased in ligated animals fed both diets; however, branched-chain amino acids were lower in the two groups fed more branched-chain amino acids.

Inflammatory cells in graft-versus-host disease on the rectum: immunopathologic analysis.

The inflammatory infiltrate of acute rectal graft-versus-host disease (GVHD) was investigated by indirect immunofluorescence. Twenty biopsies from 11 allogeneic bone marrow transplant recipients were studied in four groups: biopsies before transplantation; biopsies after transplantation without GVHD; biopsies from patients with extra-intestinal GVHD only; and biopsies from patients with intestinal GVHD. Total T cell numbers (CD2+, CD3+) in the lamina propria differed little in the four groups. CD4+ lymphocytes appeared to be decreased in GVHD while CD8+ lymphocytes were significantly increased (p less than 0.01), thus significantly lowering the CD4/CD8 ratio. In pre-transplant patients and in those without GVHD this ratio resembled that in normal peripheral blood (1.44 +/- 0.5 and 2.46 +/- 1.3, respectively) but was significantly lower in both extraintestinal (0.71 +/- 0.08) and intestinal GVHD (0.56 +/- 0.08) (p less than 0.05). Acute intestinal GVHD was marked by a fourfold increase in CD57+ lymphoid cells within the epithelium and the lamina propria (p less than 0.05). The recognition of CD57+ cells, which may include natural killer-like cells, within rectal lymphoid infiltrates suggests a possible role for non-HLA restricted effector cells in GVHD of the rectum.

Plasma amino acids in long-term models for obstructive versus toxic liver injury in developing rats.

We evaluated plasma amino acid (AA) concentrations associated with a histologically defined lesion caused by bile duct ligation (BDL) in developing rats. Nineteen rats that underwent BDL at 14 days of age had marked bile duct proliferation with bridging fibrosis, multifocal lobular necrosis, and minimal polymorphonuclear periportal infiltrate in their livers at sacrifice (11-31 days after ligation). These were compared to two age-matched control groups: 21 nonoperated rats and 22 sham-operated rats; and eight rats with cirrhosis caused by carbon tetrachloride. Signs of liver damage including jaundice, growth failure, bleeding, and ascites were accompanied by elevated bilirubin, ammonia, aspartate aminotransferase (AST), and alkaline phosphatase levels in BDL rats compared to controls. They had higher concentrations of total AAs, phenylalanine, tyrosine, and cyst(c)ine when compared to controls and to CCl4-treated rats. Micronodular cirrhosis was present in CCL4-treated rats with elevated AST and alkaline phosphatase levels. Glutamine and glutamate levels were higher in them than in BDL rats or controls, and branched chain AA levels were lower. These two chronic lesions, one obstructive and one hepatotoxic, both result in fibrotic change, but their metabolic abnormalities as reflected in plasma AA levels are distinct. We found that BDL is an appropriate model with which to study metabolic changes and growth failure due to chronic biliary stasis during its progression to frank cirrhosis.

Growth failure in cholestatic rats: the effect of malnutrition on insulin-like growth factor I.

Low IGF-I levels are found in patients with chronic liver disease, but it is not known whether these reductions in IGF-I are secondary to hepatic dysfunction or to malnutrition. To determine whether malnutrition associated with hepatic dysfunction causes the decrease in these levels, serum and liver IGF-I concentrations and liver IGF-I mRNA content were compared in three groups of Sprague-Dawley rats: 15 rats underwent bile duct obstruction; 10 rats were sham-operated and pair-fed with operated rats to control for nutritional status; and 12 rats were sham-operated controls fed ad libitum. In addition, IGF-I peptide and mRNA were compared with food intake, crude nitrogen balance, total wt gain, tail length increase and leg muscle wt. All the parameters were lower in cholestatic and nutritionally deprived animals than in control animals (p less than 0.001). There was no difference in serum and hepatic IGF-I and liver IGF-I mRNA values between the 10 cholestatic and pair-fed animals, despite lower crude nitrogen balance, tail length gains, and leg muscle wt in the bile duct-obstructed animals. These studies suggest that in chronic bile duct obstruction, the low serum and hepatic IGF-I levels are primarily due to decreased food intake and appear unrelated to cholestatic liver disease itself. However, factors in addition to suboptimal nutrition and decreased IGF-I levels must also contribute to cholestasis-induced growth failure.

Pyrochemiluminescence: real-time, cost-effective method for determining total urinary nitrogen in clinical nitrogen-balance studies.

Total urinary nitrogen (TUN) determinations for nitrogen-balance studies were traditionally performed by the Kjeldahl method, but this method is laborious, hazardous, prone to error, and no longer widely available in most clinical laboratories. During the last several decades, urinary urea nitrogen (UUN) determinations have replaced TUN as an index of urinary nitrogen excretion in many clinical laboratories, owing to its ease of determination, decreased cost, and wide availability. However, the validity of using UUN for estimating nitrogen loss has been questioned in many disease states, owing to wide variations in the proportional amount of urea found in TUN. Chemiluminescence has been proposed as an alternative to the Kjeldahl method for TUN. TUN values obtained from 24-h urine collections measured by both micro-Kjeldahl (x) and Pyrochemiluminescence (y) (Antek Instruments, Inc.) techniques were comparable by linear regression analysis: n = 97; r = 0.996; r2 = 0.992; y = 1.048x - 0.606; P less than 0.001. Automated induction of samples and calculation of results allows up to 42 samples to be run unattended. This dramatically reduces labor and overall costs for TUN determinations, while providing a more accurate and economical assessment of nitrogen excretion than UUN in a clinical setting.

Amino acid abnormalities in infants with extrahepatic biliary atresia and cirrhosis.

We measured fasting plasma amino acids in 26 children aged 6 months to 5 years with extrahepatic biliary atresia and cirrhosis and compared them with fasting values in 95 normal control children aged 4 months to 12 years. We found that the cirrhotic children had elevations of total free plasma amino acids implying reduced hepatic metabolism of amino acids and that the molar ratio of the branched chain amino acids (isoleucine, leucine, and valine) to the aromatic amino acids (phenylalanine and tyrosine) was significantly depressed. Methionine was also markedly elevated, and taurine concentrations were significantly decreased. Manipulation of the amino acid distribution in dietary protein to normalize plasma amino acids prior to orthotopic hepatic transplantation may be helpful in improving amino acid utilization.

Cord transferrin and ferritin values in newborn infants at risk for prenatal uteroplacental insufficiency and chronic hypoxia.

We measured cord transferrin and ferritin levels in 50 newborn infants with fetal conditions associated with either uteroplacental vascular insufficiency or chronic hypoxia. Sixteen small for gestational age infants, 21 infants of mothers with preeclampsia, and 13 symptomatic infants of diabetic mothers had significantly higher transferrin levels and lower ferritin levels and calculated iron stores than did asymptomatic gestational age-matched control infants without these conditions. Cord ferritin levels and calculated iron stores were significantly lower in the infants of diabetic mothers than in any other group of infants. Cord transferrin levels were inversely correlated with ferritin levels (r = -0.59, P less than 0.001) and were unrelated to transthyretin levels and birth weight in the high-risk infants, but were positively correlated with ferritin levels (r = 0.50, P less than 0.001), transthyretin levels (r = 0.65, P less than 0.001), and birth weight (r = 0.75, P less than 0.001) in the control infants. We conclude that cord transferrin levels do not reflect protein-energy status in newborn infants with prenatal histories suggesting uteroplacental insufficiency or chronic hypoxia, and that when associated with decreased cord ferritin levels, indicate possible impaired iron stores in these infants.

Positive effect of prophylactic total parenteral nutrition on long-term outcome of bone marrow transplantation.

In a randomized trial we studied the impact of providing total parenteral nutrition (TPN) to bone marrow transplant (BMT) patients during their cytoreductive therapy, and for 4 weeks following BMT, on 8 parameters of outcome. A total of 137 patients over 1 year of age and with normal nutritional status were randomized either to receive TPN starting one week prior to transplant or to receive hydration with a 5% dextrose solution containing electrolytes, minerals, trace elements, and vitamins. TPN was ultimately required by 40 of the 66 control patients when nutritional depletion was documented. Average total calorie and protein intake was significantly higher for the TPN group than for the control group. Minimum follow-up was 1 year and median was 2 years. Overall survival, time to relapse, and disease-free survival were significantly improved in the TPN group. Engraftment, duration of hospitalization, and incidences of acute and chronic graft-vs.-host disease and bacteremia were not different. Thus TPN during BMT had a positive effect on long-term outcome. Prophylactic nutritional therapy appears to be indicated even for well-nourished individuals during cytoreduction and BMT.

The plain abdominal radiograph in acute gastrointestinal graft-vs.-host disease.

The plain abdominal radiographs of 28 patients with acute gastrointestinal graft-vs.-host disease (GVHD) were examined to determine the plain radiographic findings associated with this disorder. These findings, in order of decreasing frequency, included air-fluid levels, bowel wall/mucosal fold thickening, gasless abdomen, bowel dilatation, pneumatosis intestinalis, and ascites. When a number of these findings are present, the plain abdominal radiographs may be sufficiently characteristic to suggest gastrointestinal GVHD. Differentiating acute gastrointestinal GVHD from small-bowel obstruction is often of major clinical importance. Fortunately, the bowel gas pattern in acute gastrointestinal GVHD rarely suggests obstruction and, thus, bowel obstruction can usually be excluded on the basis of plain radiographs alone.

A histopathologic study of gastric and small intestinal graft-versus-host disease following allogeneic bone marrow transplantation.

Twenty-two stomach and 14 small intestinal biopsy specimens from 24 allogeneic bone marrow transplant recipients were reviewed to evaluate the histopathologic changes of graft-versus-host disease (GVHD) in these organs. Associations between these results and clinical symptoms and other biopsy results were sought. In both organs, single epithelial cell necrosis was found to correlate with GVHD. Gastric GVHD was diagnosed in eight patients and small intestinal GVHD in four. Gastric GVHD was characterized by nausea, vomiting, and upper abdominal pain without diarrhea (the latter being present in only two patients), while all four of the patients with small intestinal GVHD had upper gastrointestinal symptoms and diarrhea. These symptoms correlated with concurrent rectal biopsy findings; pathologic alterations were seen in only one of six specimens from patients with gastric GVHD but in three of four with small intestinal GVHD. These findings suggest that stomach biopsy may be necessary to diagnose GVHD in patients with upper gastrointestinal symptoms but no diarrhea and normal rectal biopsy specimens. Diagnostic problems may arise in the early posttransplantation period, when the effects of cytoreductive therapy may simulate GVHD, and in patients with gastrointestinal cytomegalovirus infection, which may also produce changes identical to those of GVHD.

Hepatic graft versus host disease: a study of the predictive value of liver biopsy in diagnosis.

Ninety-six liver biopsies [32 bone marrow transplant (BMT), 7 pre-BMT, and 57 non-BMT] are reviewed for histological evidence of graft versus host disease (GVHD), based on bile duct atypia and related inflammatory changes. In addition, the presence of cholestasis, piecemeal necrosis, and attachment of lymphocytes to vascular endothelium (endothelialitis) are evaluated. The 57 non-BMT biopsies include examples of viral hepatitis (acute and chronic), nonviral chronic hepatitis, extrahepatic biliary obstruction, cytomegalovirus hepatitis, primary biliary cirrhosis, and orthotopic liver transplant rejection. Although the sensitivity of bile duct damage as an indicator of GVHD appears high (only one probable false negative was noted), there is considerable overlap between the changes of GVHD and occasional cases of acute and chronic hepatitis and extrahepatic biliary obstruction. Nine of the 57 non-BMT biopsies (15%) were felt to be consistent with GVHD and represent "false positives". Despite this relative lack of specificity, analysis of several features in combination provided clues to improve accuracy of diagnosis. The findings of extensive bile duct damage with minimal inflammatory changes is characteristic of GVHD. Possibly more predictive is the presence of endothelialitis of portal or central veins, which was seen in only three non-BMT biopsies, being present in eight cases of GVHD.

Graft-versus-host disease of the intestine: a protein losing enteropathy characterized by fecal alpha 1-antitrypsin.

Severe hypoproteinemia often accompanies the development of graft-versus-host disease of the intestine in allogeneic bone marrow transplant patients. To determine whether or not protein loss occurs across the intestinal mucosa in this severe diarrheal illness, we measured fecal alpha 1-antitrypsin once per week in 24-h stool specimens from 25 consecutive patients during hospitalization for bone marrow transplantation. The mean alpha 1-antitrypsin concentration and serum clearance for these patients before transplantation were below 2.6 mg/g stool and 13.0 ml/day (upper limits for normals). Values for all patients increased moderately after pretransplant conditioning. Values for patients who did not develop graft-versus-host disease of the intestine returned to baseline levels; however, those for patients with graft-versus-host disease of the intestine became markedly and persistently elevated (concentration ranged from 16.6 to 51.1 mg/g, clearance from 66.6 to 384.5 ml/day). We conclude that mucosal protein exudation contributes to the hypoproteinemia of graft-versus-host disease of the intestine and that measurement of fecal alpha 1-antitrypsin can be used as a marker for this disease.