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Biomedical subjects

C Roberts

Publications and source records attributed to C Roberts.

At least 415 records · Page 23Linked to original sources
PubMed1979

Emergency kit.

Explore the source record for details and available documents.

Emergencies↗
PubMed1979

The pancreatic duct mucosal barrier.

The main pancreatic duct in cats possesses a relatively strong barrier to the diffusion of bicarbonate ions (HCO3-). We studied some of the characteristics of this barrier by perfusing the duct with a solution similar in composition to pancreatic juice before and after exposing the duct mucosa to various test agents. The difference in net flux of HCO3- across the duct before and after exposure to the test agent reflected damage to the barrier. The barrier was damaged by infected bile, aspirin (pH 2.3), hydrochloric acid (pH 2.3), ethanol (5 to 10 per cent), and secondary bile acids. It was not damged by sterile bile, aspirin (pH 6.5), and primary bile acids. These data indicate that the barrier to back diffusion in the pancreatic duct has unique properties, different in some respects from the properties of the gastric mucosal barrier. Furthermore, the barrier is vulnerable to some agents thought possibly to have a role in the pathogenesis of pancreatitis and pancreatic cancer.

Animals↗
PubMed1979

Bacteriological monitoring of unheated human milk.

To assess the bacteriological quality of unpooled expressed breast milk, a pilot bottle sample of each donation was examined before the milk was given to the neonate. Provided the milk did not contain greater than 2500 organisms/ml or potential pathogens it was used unheated. Milk containing between 2500 and 5000 organisms/ml and no potential pathogens was used after pasteurisation. Using these criteria, 67% of 460 donations were acceptable. However, because the bacteriological quality varied, 45% of domiciliary donations were discarded compared with only 29% of those from hospital.

Bacteriological Techniques↗
PubMed1979

Grouping of streptococci by Streptex.

Streptex was compared to routine laboratory identification methods available. The results from Streptex sometimes required several attempts before final identification could be achieved. In the main, group D streptococci other than Strep. faecalis failed to group with the Streptex antisera, and this method cannot therefore be used exclusively as a means of identifying this group of streptococci.

Immune Sera↗
PubMed1978

Management of external gastrointestinal fistulas.

We analyzed the course of 186 patients with external gastrointestinal fistulas treated at the University of California Medical Center, San Francisco from 1968 to 1977. There were 82 patients in the earlier group (1968-1971) and 104 patients in the later group (1972-1977). The groups differed in that 35% of patients in the earlier group received TPN, but 71% of patients in the later group received TPN. Of the patients who did not receive TPN, 93% had been adequately nourished using tube feeding methods. The two groups were otherwise similar. The fistula-related mortality (11%) and the spontaneous closure rate of the fistulas (32%) was unchanged over the ten year period. Thus, the principal impact of TPN was to simplify the nutritional management rather than to alter the outcome. When malignancy, previous abdominal irradiation, Crohn's disease, or a short (<2 cm) fistula tract were present, spontaneous closure was less likely than when none of these factors were present (20% versus 47%). Sixty-eight per cent of the deaths occurred in patients with uncontrolled sepsis. Fifty per cent of the deaths were due to the primary disease and were unrelated to the fistula. Spontaneous closure could not be expected to start until sepsis was controlled. Because over 90% of patients whose fistulas closed spontaneously did so within one month after infection was eradicated, we recommend operative closure for most fistulas that persist beyond that time. The most reliable operation is excision of the bowel from which the fistula arises with end-to-end anastomosis. Fistulas not amenable to excision should be managed by bypass.

Adolescent↗
PubMed1977

Influence of probenecid and spironolactone on furosemide kinetics and dynamics in man.

The pharmacokinetics and pharmacodynamics following administration of furosemide (40 mg intravenously) have been studied before and after treatment with probenecid (0.5 gm orally every 6 hr for 3 days) and spironolactone (200-mg initial oral dose followed by 50 mg every 6 hr for 3 days) in 6 normal male subjects. Urine losses during each study period were replaced with saline-dextrose-KCl intravenously. The study was performed with the use of a Latin-square design. Probenecid pretreatment induced significant reductions in renal clearance of furosemide by 78%, the extrarenal clearance by 56%, and the volume of distribution by 52%. As a consequence, furosemide half-life was increased by 54%. Probenecid significantly reduced the rate of sodium excretion at all plasma concentrations of furosemide, but the ratio between urinary furosemide concentration and urinary sodium concentration was not altered. Since the proportion of furosemide excreted unchanged in the urine was not markedly changed, total diuretic response was not influenced by probenecid. There was no evidence of any pharmacokinetic interaction between spironolactone and furosemide. The relationship of furosemide kinetics to dynamics observed in these studies confirms that, in man, the diuretic response is determined by drug that reaches the renal tubule rather than the drug level in plasma.

Adult↗
PubMed1976

Ultrasound in the assessment of vascular function.

The study of circulatory function is fundamental to the understanding of many physiological processes and pathological conditions, and has been greatly advanced by developments in the use of ultrasound. Transcutaneous measurement of blood velocity has been made possible by the use of Doppler shift methods, and many methods of spectral analysis have been developed. Blood volumetric and flow profiles can be achieved through the use of range-gated pulsed Doppler systems. A combination of Doppler velocimetry, pressure measurements and volumetric visualisations provide a powerful alternative to more conventional investigations like arteriography. Current developments indicate that the use of ultrasound in investigating vascular function is cost effective.

Blood Flow Velocity↗