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Query: UMLS:C0017536 (giardiasis)
 1,714 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Infection with Giardia lamblia often causes only minor mucosal changes to the small intestine yet frank fat malabsorption may still occur. Some evidence suggests abnormal pancreatic exocrine function in subjects with giardiasis although the mechanism and significance of this is unclear. Studies were conducted in vitro to determine the effect of G. lamblia trophozoites or culture filtrates from the organism on lipolysis of triglyceride by porcine pancreatic lipase. Live trophozoites significantly inhibited lipolysis. The degree of inhibition increased with longer duration of lipase exposure to trophozoites. Total amounts of enzyme inhibited were proportional to enzyme concentration, while the percentage inhibition was greatest at lowest concentration. At a lipase concentration of 1.7 i.u./ml, enzyme activity was reduced by 89.7% compared to controls after incubation for 4 h with trophozoites. The effect was abolished using killed, intact trophozoites. Culture filtrates of G. lamblia did not inhibit lipolysis. Specificity of the effect was suggested by the failure of another flagellate protozoan, Trichomonas vaginalis, to inhibit lipase. In this assay system the inhibition of lipolysis was not dependent on the bile salt concentration present. The impact of this effect in vivo remains to be determined but it may contribute to fat malabsorption in giardiasis.
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PMID:The effect of Giardia lamblia trophozoites on lipolysis in vitro. 194 23

Giardia lamblia localize and multiply in the small intestine and may cause acute or chronic diarrhoea with malabsorption of fat, protein and other nutrients. Abnormal pancreatic function has been documented in giardiasis and trophozoites directly inhibit pancreatic lipase activity in vitro. The aim of this study was to examine the effect of Giardia trophozoites on pancreatic trypsin, chymotrypsin and amylase activity in vitro. Axenically cultured Giardia trophozoites (Portland-1 stock) were incubated with a range of concentrations of trypsin, chymotrypsin and amylase and enzyme activity assayed over time. Tryptic activity was decreased after incubation with Giardia trophozoites. This reduction was time dependent and linear over the incubation period of 2 h. At a trypsin concentration of 18 BAEE units/ml, there was a 35.5 +/- 4% reduction in enzyme activity after 2 h compared to controls. The total amount of activity lost was proportional to the initial trypsin concentration up to 185 BAEE units/ml. At this initial concentration, the activity was reduced by 46.5 +/- 3 units/ml after 2 h. Above this concentration, little further loss of enzyme activity was seen. To investigate the nature and specificity of this effect, similar experiments were conducted using killed trophozoites and with a related protozoan, Trichomonas vaginalis. No loss of enzyme activity was evident. Media previously incubated for 2 h with trophozoites did not diminish tryptic activity. Trophozoites had no effect on chymotrypsin or amylase activities over the range of concentrations tested.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:The effect of Giardia lamblia trophozoites on trypsin, chymotrypsin and amylase in vitro. 848 60