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Biomedical subjects

I M Roberts

Publications and source records attributed to I M Roberts.

At least 55 records · Page 3Linked to original sources
PubMed1987

Radioimmunoassay for human pancreatic lipase in acute pancreatitis.

We examined the utility of serum pancreatic lipase by radioimmunoassay as a diagnostic test for acute pancreatitis and its correlation with serum total amylase, pancreatic isoamylase, and lipase activity. Data were analyzed on 11 patients with documented acute pancreatitis, three groups of patients (N = 104) with nongastrointestinal, gastrointestinal, and renal diseases, and 30 healthy controls. Patients with acute pancreatitis had significantly (P less than 0.01) higher mean serum lipase by radioimmunoassay than all other groups. Using a serum lipase of 112 ng/ml as a cutoff point in all patients, the test was 91% sensitive and 96% specific for the diagnosis of acute pancreatitis. The correlation coefficients of serum lipase by radioimmunoassay with respect to total amylase, pancreatic isoamylase, and lipase activity were 0.86, 0.98, and 0.79, respectively.

Acute Disease↗
PubMed1987

Breast milk composition and bile salt-stimulated lipase in well-nourished and under-nourished Nigerian mothers.

Breast milk was analysed in 9 under-nourished Nigerian mothers and 23 well-nourished mothers who served as controls. Milk from the under-nourished mothers contained adequate amounts of lactose and total triglycerides, but had significantly lower bile salt-stimulated lipase activity (BSSL); their mean BSSL activity was only about 50% of the activity in milk from the control group. Total milk protein was also significantly lower than for the controls (1.45 vs. 1.09 g/dl, respectively; P less than 0.01). Our findings may have nutritional implications for breast-fed infants of under-nourished nursing mothers.

Adult↗
PubMed1987

Immunocytochemical localization of lingual lipase in serous cells of the developing rat tongue.

The ontogeny of the rat lingual serous and mucous glands was explored by light and electron immune microscopy using the peroxidase-antiperoxidase and streptavidin-gold techniques. Tissues from fetal and neonatal rats from day 18 of gestation through 4 wk after birth were fixed and embedded in paraffin or Epon for light and transmission electron microscopy, respectively. Electron microscopy revealed that the only cells containing lingual lipase were the developing serous cells; secretory granules containing lingual lipase of varying degrees of maturity were seen. Mucous cells did not show immunospecific staining in rats of any age. The neonatal "mixed" lingual glands secrete lingual lipase from serous components immediately after birth to aid in fat digestion.

Animals↗
PubMed1987

Modulation of low density lipoprotein receptor activity by bile acids: differential effects of chenodeoxycholic and ursodeoxycholic acids in the hamster.

Hamsters were fed chenodeoxycholic acid (CDC), ursodeoxycholic acid, (UDC), or no bile acid. [14C]Sucrose-labeled hamster low density lipoprotein (LDL) and methylated human LDL were infused intravenously to study LDL receptor-dependent and LDL receptor-independent organ uptake, respectively, of LDL. Biliary CDC increased during both CDC and UDC treatment. The UDC enrichment of bile after UDC feeding was relatively small. Bile acid synthesis was suppressed after both bile acid treatments. Under the condition of an acute bile fistula, the hamster LDL uptake increased in the liver, heart, and adrenals in the CDC-treated animals. During an intact enterohepatic circulation, the hepatic uptake of hamster LDL, which accounted for a major portion of the total uptake, was increased after UDC treatment. The hamster LDL uptake in the colon, which represented only a small fraction of the total uptake, increased after CDC treatment. When hamster LDL was infused at increasing concentrations, its uptake was significantly higher in the UDC-treated than in the control and CDC-treated animals. The methylated human LDL uptake showed no significant changes in the different treatment groups under either experimental condition. The study shows significantly different effects of CDC and UDC on LDL receptor activity. Since these differences are expressed in spite of a similar suppression of bile acid synthesis, UDC may directly influence LDL receptor activity.

Albumins↗
PubMed1987

Crohn's disease of the vulva.

Vulvar involvement is an uncommon extraintestinal manifestation of Crohn's disease. A case of "metastatic" vulvar Crohn's disease occurring in a 23-yr-old woman, status post-ileocolectomy, is described. The diagnosis was established by vulvar punch biopsy, and a therapeutic response was achieved with metronidazole and prednisone. The literature on vulvar involvement with Crohn's disease is reviewed and therapeutic options are discussed.

Adult↗
PubMed1987

Aeromonas hydrophila-associated colitis in a male homosexual.

A 37-year-old homosexual man was evaluated for a one-week history of hematochezia. Results of a physical examination were remarkable only for grossly bloody stool. Sigmoidoscopy to 30 cm showed a friable mucosa compatible with an acute colitis, and a rectal biopsy specimen demonstrated an increased plasma cell infiltrate. Stool cultures subsequently yielded Aeromonas hydrophila; serum human T-cell lymphotropic virus type III antibody titer was positive. The patient responded to a course of treatment with sulfamethoxazole and trimethoprim with resolution of his symptoms and restoration of the bowel to a normal sigmoidoscopic appearance. Aeromonas hydrophila infection should be considered in the differential diagnosis of acute proctocolitis, particularly in patients with underlying immunodeficiency states.

Acquired Immunodeficiency Syndrome↗
PubMed1986

Utility of fecal fat concentrations as screening test in pancreatic insufficiency.

We explored the utility of fecal fat concentration (gram fecal fat per 100 gram wet stool weight) as a screening test for pancreatic steatorrhea. Data were analyzed on 24 patients with pancreatic insufficiency and steatorrhea, six groups of patients (N = 70) with nonpancreatic causes of steatorrhea, and 31 controls without steatorrhea. Patients with pancreatic steatorrhea had significantly (P less than 0.05) higher mean fecal fat concentrations than all groups except for patients with hepatobiliary disease. Using a fecal fat concentration of greater than 9.5% as a cutoff point in all patients with steatorrhea, the test was 41.7% sensitive and 92.0% specific for the diagnosis of pancreatic insufficiency. For patients with fecal fat excretion greater than 20 g/day, the test increased in sensitivity to 61.5% but specificity dropped to 85.3%. Measurements of fecal fat concentrations are therefore only moderately helpful, and further evidence is required to secure a diagnosis of pancreatic steatorrhea.

Celiac Disease↗
PubMed1986

Lingual lipase: immunocytochemical localization in the rat von Ebner gland.

Rat lingual lipase was purified to homogeneity by solubilization in 1% octylglucoside, followed by centrifugation, affinity chromatography on hydroxylapatite, gel filtration, and chromatofocusing. Polyclonal antibodies to the enzyme were raised in rabbits, and monospecificity was established by immunoblotting. Tissues were embedded in either paraffin or Epon for light and transmission electron microscopy, respectively. Immunocytochemical localization of the enzyme was established using the peroxidase-antiperoxidase and streptavidin-gold techniques. Immunospecific staining was observed in all acinar cells of the serous von Ebner glands, but only in the demilunes of the lingual mucous glands. The secretory granules of the acinar cells of the von Ebner glands were stained with antilipase on electron microscopic examination. No staining was observed in the salivary glands, pancreas, esophagus, stomach, or duodenum. If a true gastric lipase exists in the rat, it is immunogenically distinct from lingual lipase.

Animals↗
PubMed1986

Celiac sprue complicated by lymphoma presenting with multiple gastric ulcers.

A 40-yr-old woman with celiac sprue, which had responded clinically and histologically to gluten elimination, subsequently developed gastrointestinal lymphoma. Although this has been described in the small intestine of patients with celiac sprue, the unique feature in this patient was her initial presentation with multiple gastric ulcers refractory to conventional medical therapy. This case demonstrates that lymphoma complicating celiac sprue may present with multiple refractory gastric ulcers in addition to those occurring in the small intestine.

Adult↗
PubMed1986

Gastroesophageal reflux and Barrett's esophagus in developmentally disabled patients.

Twenty-seven patients from an institution for the developmentally disabled underwent endoscopy for evaluation of vomiting, regurgitation, rumination, or upper gastrointestinal bleeding. The presence of gastroesophageal reflux and Barrett's esophagus was determined retrospectively. Twenty-three patients had an IQ less than 20, 19 were nonambulatory, and 14 were taking at least one neuroleptic drug daily. Seven patients (26%) had histologically documented Barrett's esophagus of the specialized-columnar type. Two patients with Barrett's esophagus had benign esophageal strictures, but no cases of adenocarcinoma were found. There were no significant differences (p greater than 0.05) between patients with or without Barrett's esophagus in regard to symptoms, age, sex, IQ, medications, or ambulatory status. The present data suggest that Barrett's esophagus may frequently occur in developmentally disabled patients with symptoms and signs of gastroesophageal reflux.

Adult↗
PubMed1985

Macrophage procoagulant activity as a measure of cell-mediated immunity to P2 protein of peripheral nerves in the Guillain-Barré syndrome.

Cell-mediated and humoral immunity to purified nerve proteins has been assessed in GBS patients and compared with that of patients with other neurological diseases and healthy controls. A strong and specific cell-mediated response to the neuritogenic basic protein P2 occurred in 13/16 GBS patients tested. Extremely low levels of P2 (0.01 micrograms/culture) induced monocyte/macrophage procoagulant activity (MPCA) on peripheral blood mononuclear cells (PBM) from GBS patients (P = 0.007) whereas higher concentrations (2 micrograms/culture) of myelin basic protein (MBP) and sciatic nerve myelin (SNM) were required to stimulate similar levels of activity. These concentrations of nerve antigens failed to induce significant MPCA on peripheral blood mononuclear cells of patients with other neuropathies or healthy controls. Lipopolysaccharide, a non-specific stimulant of macrophage procoagulant activity, induced similar procoagulant levels on PBM from each group. The MPCA assay was a sensitive, quantitative and specific indicator of cell-mediated immunity to the neuritogenic peptide, P2 in GBS patients. Serum antibodies to P2, P0 and SNM were detected by a sensitive solid-phase radioimmunoassay. Naturally occurring antibodies to peripheral nerve antigens were observed in sera of healthy subjects and these levels were not significantly different from patients with GBS or those with other neuropathies. Our results indicate that the autoimmune cell-mediated response to the neuritogenic peptide P2 plays a major role in the pathogenesis of GBS.

Adolescent↗
PubMed1985

Rat lingual lipase: effect of proteases, bile, and pH on enzyme stability.

In addition to initiating fat digestion in the stomach, lingual lipase may play a significant digestive role in the upper small intestine. By in vitro incubation techniques, the stability of rat lingual lipase at various physiological pH values, as well as the effects of pure proteases, rat gastric juice, bile, pancreatic juice, and mixed duodenal contents, on enzyme activity was explored. There were no changes in base-line activity of porcine pepsin, bovine carboxypeptidase-treated lipase, or heat-denatured proteases compared with controls after incubation at pH 2-6 at 37 degrees C for up to 1 h. In contrast, porcine trypsin-treated lipase demonstrated a significant loss from base-line activity to 59 +/- 12% (mean +/- SE) at pH 4, 34 +/- 11% at pH 6, and 41 +/- 4% at pH 8, and bovine chymotrypsin caused a loss in lipase activity to 11 +/- 7% at pH 8. Rat gastric juice containing 5,000 U pepsin reduced lipase activity to 17 +/- 5% of initial activity at pH 2 and to 45 +/- 3% at pH 4. Rat bile alone diminished activity only 35%, but rat pancreatic juice or mixed duodenal juice reduced lingual lipase activity to 1-12% of initial activity after 60 min at pH 6. Lingual lipase is particularly important in fat digestion in the stomach; however, its role in quantitative fat digestion under small intestinal conditions may be limited.

Animals↗
PubMed1984

Rat lingual lipase: partial purification, hydrolytic properties, and comparison with pancreatic lipase.

We have partially purified lingual lipase from the serous glands of rat tongue. With a combination of Triton X-100 extraction or Triton X-114 phase-separation techniques, Bio-Bead SM-2 treatment, dialysis, and gel filtration on Sephadex G-200 or Sephacryl S-300, we obtained a sparingly soluble lipid-free protein demonstrating hydrolytic activity against triglycerides and negligible phospholipase or cholesteryl esterase activities. Compared with homogenate, specific activities of the enzyme were enriched 3- to 5-fold prior to gel filtration and 10-fold after gel filtration. Analysis by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and gel filtration under denaturing conditions (6 M guanidine X HCl or 0.1% sodium dodecyl sulfate) revealed one major glycoprotein band with Mr approximately 50,000. Gel filtration of the active enzyme in 0.1% Triton X-100 gave an Mr approximately 270,000-300,000, suggesting extensive self-aggregation. With both tributyrin and triolein, the pH optimum of the purified enzyme was 4.0 and activity extended from pH 2.0 to 8.0. In contrast to purified human pancreatic lipase, lingual lipase hydrolyzed triglyceride emulsions and mixed micelles stabilized with both short-chain (dihexanoyl) and long-chain (egg) lecithin and were inhibited only slightly (18-25%) by micellar concentrations of two common bile salts, taurodeoxycholate and taurocholate. Our results suggest that the hydrolysis of dietary fat by lingual lipase may extend from the pharynx through the esophagus and stomach and into the upper small intestine.

Animals↗
PubMed1984

Susceptibility and resistance to experimental autoimmune encephalomyelitis and neuritis in the guinea pig correlate with the induction of procoagulant and anticoagulant activities.

Activation of macrophage procoagulant activity (MPCA) is involved in the manifestation of EAE and EAN in susceptible guinea pigs and provides a mechanism for the deposition of fibrin, which is a feature of histologic lesions of EAE. Peritoneal exudate cells (PEC) from susceptible (strain 13) guinea pigs immunized with either central or peripheral nervous tissue antigens produce procoagulant activity when incubated with the immunogen in vitro. The production of the procoagulant is quantitative and antigen-specific and is maximal at the time of clinical signs of the disease. After recovery, the production of procoagulant activity decreased. The MPCA test was able to discriminate the biochemical differences existing between chicken and mammalian peripheral nerve proteins, thus providing a quantitative and sensitive indicator of cell-mediated immunity in EAE and EAN. The autoimmune response to brain and nerve antigens in nonsusceptible (strain 2) guinea pigs was coincident with the antigen-specific production of a cell-bound anticoagulant activity by stimulated mononuclear cells. The production of anticoagulant activity followed the same sequence of time changes after immunization as that of the MPCA in susceptible guinea pigs, and high immunizing doses of nerve antigens induced high levels of anticoagulant activity. The same cells produced high levels of procoagulant when incubated with tuberculin or lipopolysaccharide. The recalcification time of normal plasma was prolonged by the anticoagulant, and the decreased clotting time of plasma induced by the procoagulant activity obtained by incubating sensitized strain 13 PEC with myelin basic protein was suppressed by the anticoagulant produced by culturing sensitized strain 2 PEC with myelin basic protein. Preliminary evidence indicates that the anticoagulant has properties similar to antithrombin III. The anticoagulant could play a role in the control of effector cell function, and therefore in recovery from clinical features of EAE and EAN in susceptible guinea pigs.

Animals↗
PubMed1982

Suggested terminology for virus/antibody interactions observed by electron microscopy.

Six terms are recommended to describe the techniques applied and the effects observed when antibody/virus particle interactions are examined in the electron microscope. These are: immunoelectron microscopy, immunosorbent electron microscopy, antiserum- (or antibody-)coated grids, trapping, clumping and antibody coating. These recommendations are intended to assist authors and editors alike, by decreasing the confusion resulting from the use of a wide variety of alternative terms.

Antibodies, Viral↗