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Biomedical subjects

C J Mitchell

Publications and source records attributed to C J Mitchell.

At least 127 records · Page 7Linked to original sources
PubMed1981

Clinical value of serum immunoreactive trypsin concentration.

The clinical value of estimation of serum concentrations of immunoreactive trypsin was evaluated by studying 46 healthy controls, 23 controls in hospital, 44 patients with chronic pancreatic disease, and 184 patients with non-pancreatic conditions in which pancreatic disease commonly enters into the differential diagnosis. Serum trypsin concentration had a log normal distribution in the controls, and the calculated normal range was considerably wider than that previously reported. The concentration was abnormal in only 13 out of 27 patients with chronic pancreatitis and was extremely variable in patients with pancreatic cancer. Abnormal results occurred in 11% of the patients with non-pancreatic disease. Eighteen patients had a subnormal trypsin concentration, of whom six did not have pancreatic disease and 12 had either chronic pancreatitis or pancreatic cancer. There was no correlation between serum trypsin concentration and mean tryptic activity as measured by the Lundh test. Of 11 patients with pancreatic steatorrhoea, only seven had subnormal trypsin concentrations. There results suggest that the serum concentrations of immunoreactive trypsin has a low specificity and sensitivity for pancreatic disease and does no reflect the degree exocrine insufficiency in patients with proved chronic pancreatitis.

Celiac Disease↗
PubMed1981

Preliminary evaluation of a single-day tubeless test of pancreatic function.

The test for pancreatic exocrine function using N-benzoyl-L-tyrosyl-p-aminobenzoic acid (BTP test) does not require duodenal intubation, but misleadingly abnormal results often occur in patients with liver or bowel disease because the p-aminobenzoic acid (PABA) released by chymotrypsin hydrolysis of the peptide either is not conjugated or is malabsorbed. This study evaluated a modified BTP test, using a tracer dose of 14C-PABA to eliminate misleading results, to assess exocrine function from a single six-hour collection of urine. The test clearly distinguished all patients with pancreatic steatorrhoea from normal subjects and identified patients with less severe pancreatitis as often as did the Lundh test. Furthermore, in patients with bowel or liver disease the misleadingly abnormal results of the unmodified BTP test were eliminated by the modified test in all but one case. These findings suggest that the modified BTP test provides a practical alternative to conventional tests of pancreatic function that entail duodenal intubation.

4-Aminobenzoic Acid↗
PubMed1981

Studies on the absorption of the pancreatic function test peptide, N-benzoyl-L-tyrosyl-p-aminobenzoic acid, and related compounds by isolated rat small intestine.

The peptide, N-benzoyl-L-tyrosyl-p-aminobenzoic acid, which is used in an oral test of pancreatic function, has been perfused through isolated rat small intestine in order to determine whether it can be absorbed across the intestine in intact form, and whether it is hydrolysed appreciably by intestinal enzymes. For comparison, transport of N-benzoyl-DL-tyrosine, L-tyrosine, L-tyrosyl-L-leucine and p-aminobenzoic acid has also been studied. Very small amounts of bound tyrosine (probably mainly intact peptide plus some benzoyl-tyrosine) and of free p-aminobenzoic acid crossed the intestine during perfusion with N-benzoyl-L-tyrosyl-p-aminobenzoic acid. Adsorbed pancreatic enzymes were possibly responsible for the very small amount of hydrolysis of the peptide. However, no detectable free tyrosine crossed the intestine during perfusion with N-benzoyl-L-tyrosyl-p-aminobenzoic acid or with N-benzoyl-DL-tyrosine. In contrast, substantial quantities of free tyrosine crossed the intestine during perfusion with L-tyrosine or with L-tyrosyl-L-leucine. Net transport of tyrosine from L-tyrosyl-L-leucine was less than that from equimolar free L-tyrosine; no detectable intact L-tyrosyl-L-leucine crossed the intestine. During perfusion with free p-aminobenzoic acid the concentration in the serosal secretion apparently exceeded that in the lumen by a factor of 1.7; this suggests active transport of p-aminobenzoic acid.

4-Aminobenzoic Acid↗
PubMed1980

Variation in virulence for mice and rhesus monkeys among St. Louis encephalitis virus strains of different origin.

The virulence characteristics of 67 strains of St. Louis encephalitis (SLE) virus isolated from various sources in North, Middle, and South America were compared in mice and rhesus monkeys. Each virus strain was titrated in mice exactly 21 days old and virulence was expressed as the ratio of intracerebral (ic)/intraperitoneal (ip) LD50. Virus strains fell into three groups: 1) high virulence (ic/ip LD50 ratio approximately 1.0); 2) intermediate virulence (variable mortality over a wide dose range); and 3) low virulence (ic/ip LD50 less than or equal to 0.00002). Virus strains isolated during Culex pipiens and Cx. nigripalpus--borne epidemics in the eastern United States were highly virulent for mice, whereas a high proportion of the endemic virus strains isolated from Cx. tarsalis in the western United States were attenuated. Virus strains isolated from birds (the usual host for SLE virus) were highly virulent, in contrast to strains from rodents and carnivores, which were attenuated. Isolates from humans exhibited variable virulence characteristics. In experimentally-infected mice, virulence correlated with high viremia, replication in extraneural tissues, and earlier neuroinvasion. Mouse virulence correlated with clinical and histopathologic markers of pathogenicity for ic inoculated rhesus monkeys. Monkeys immunized with nonpathogenic strains by subcutaneous inoculation were partially protected against ic challenge with a virulent virus strain. The virulence classification of SLE virus strains is discussed in terms of epidemiologic correlations. This classification provides a framework for future studies on the antigenic, genetic, and biochemical bases for SLE virus strain variation.

Animals↗
PubMed1979

Clinical relevance of an unfused pancreatic duct system.

In man, the main pancreatic duct is normally derived from ventral and dorsal embryological buds of the pancreas. In a minority of people, failure of fusion of the two buds results in separate drainage of the dorsal and ventral pancreas, so that the accessory duct provides the main drainage for the gland. Patients with this anomaly demonstrated at endoscopic retrograde pancreatography (ERP) have been investigated to assess whether non-fusion of the main pancreatic duct predisposes to the development of pancreatitis. A failure of fusion of the pancreatic ducts was seen in 21 out of 449 (4.7%) successful pancreatograms; four of these 21 patients had definite clinical evidence of pancreatitis and two patients had possible pancreatic disease, but in the remainder the anomaly was not considered to be clinically relevant. An abnormal pancreatogram suggesting pancreatitis was present in 116 out of the 428 patients (27.1%) with a normally fused duct system. The anomaly was found as frequently in the whole series as it was seen in patients with pancreatitis. These findings suggest that embryological failure of pancreatic duct fusion does not predispose to the development of pancreatitis. However, the presence of this anomaly may lead to misinterpretation of ultrasonographic and CT scan findings.

Adolescent↗
PubMed1979

Gastric function and histology in chronic renal failure.

Gastric function and histology were investigated in 24 patients with untreated chronic renal failure. At endoscopy nine patients had oesophagitis, 12 patients were considered to have gastritis, and the duodenum appeared inflamed in 20 patients. Endoscopic biopsies were taken at standard sites in the stomach and duodenum; gastritis was found in all patients, and 17 patients had duodenitis. Stimulated acid secretion was impaired in seven out of 20 patients and acid hypersecretion was found in a further two patients. Pepsin output correlated well with acid output in these patients. Fasting serum gastrin levels were elevated in 12 of the 19 patients tested. Patients with atrophic gastritis had low acid outputs and hypergastrinaemia, and when extensive gastritis was present, the patients tended to have more severe renal failure and hyposecretion of acid. Three patients were studied again after regular haemodialysis or renal transplantation and were found to show marked endoscopic and histological improvement.

Adult↗
PubMed1979

Radiation pancreatitis: a clinical entity?

2 cases of pancreatic disease in patients with malabsorption following small bowel radiation injury are reported. It is suggested that the pancreatic disease present in these patients occurred as a result of previous radiotherapy.

Humans↗
PubMed1979

The diagnostic value of the oral pancreatic function test.

An oral pancreatic function test (PFT) using the synthetic peptide N-benzoyl-L-tyrosyl-p-aminobenzoic acid can assess pancreatic exocrine function, since urinary recovery of the ingested dose is an indirect index of chymotryptic activity. We have studied 34 subjects using this oral PFT, which correctly distinguished the control group (8 subjects) from the pancreatitis group (10 patients), results correlating well with Lundh test findings. However, the test was falsely abnormal on 9 out of 16 occasions in patients with bowel or liver disease. We therefore conclude that the present test cannot distinguish small-bowel disease from pancreatic disease, which is often the diagnostic problem, and is also frequently falsely abnormal in the presence of chronic liver disease.

4-Aminobenzoic Acid↗
PubMed1979

Improved diagnostic accuracy of a modified oral pancreatic function test.

The oral pancreatic function test (PFT) depends upon urinary recovery of p-aminobenzoic acid (PABA) released by chymotrypsin hydrolysis of orally administered N-benzoyl-L-tyrosyl-p-aminobenzoid acid. The diagnostic value of the test is limited because falsely abnormal results frequently occur in patients with bowel or liver disease in whom PABA recovery is impaired by abnormal absorption or hepatic conjugation, even though pancreatic function is normal. To overcome this problem, we have modified the oral PFT to correct for impaired PABA absorption and conjugation. Results of the oral PFT have been compared with urinary recovery of an equivalent dose of free PABA in order to derive a PABA excretion index (PEI). When the modified oral PFT is used, the PEI clearly distinguished patients with pancreatic disease from normal subjects. In patients with small-bowel or liver disease and normal exocrine pancreatic function, the PEI results were similar to those of normal subjects, although a previous oral PFT had been falsey abnormal. The modified test can therefore distinguish abnormal results due to pancreatic disease from the falsely abnormal results found in liver and small-bowel disease.

4-Aminobenzoic Acid↗
PubMed1978

Streptococcus suis type II (group R) as a cause of endophthalmitis.

A case is reported of a patient with bilateral endophthalmitis, meningitis, sensorineural deafness, labyrinthitis, and septicaemia due to Streptococcus suis type II (group R). The organism is known to produce epidemic meningitis, septicaemia, and purulent arthritis in piglets, but human infection is rare, and no other case reports of ocular infection are known. The organism was sensitive to penicillin at a minimum inhibitory concentration of 0.03 mg/1.

Deafness↗