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Vitamin a solubility in micellar solutions
50
T H E ROYAL COLLEGE OF PATHOLOGISTS O F AUSTRALIA
prepared for light microscopy and stained by the following methods : H & E, PAS, PAS-diatase, PTAH, Masson’s trichrome, Connor’s crystal violet-acid fuchsin, Puchler’s PAS-tannic acid-phosphomolybdic acid-levanol fast cynanine 5RN, Lie’s haematoxylin-basic fuchsin-picric acid. Following 40 min-2 h of arterial occlusion or autolysis, affected tissue showed a loss of glycogen which was recognizable in PASor Puchtler-stained sections. From 2 h onward the myofibres of infarcted tissue showed structural alterations detectable with H & E but were more clearly shown by PTAH, Connor’s, Putchtler’s and Masson’s stains. After 6 or more h of arterial Qcclusion the infarcted tissue was clearly defined in all preparations by neutrophil infiltration. Lie’s stain, which is said to produce a specific general colour reaction in infarcted tissue, gave inconsistent results and the differentiation time was extremely critical. Thus, although staining by Puchtler’s technique appears to be the most valuable method for determining the presence and age of early experimental infarcts, its application to human autopsy material is limited by the glycogen depletion which occurs during autolysis. TOXOPLASMOSIS IN DASYURID MARSUPIALS : A FINAL CHAPTER
ATTWOOD,H. D. and WOOLLEY, P. A,, Department of Pathology, University of Melbourne, Deparrment of Zoology, La Trobe University, Victoria
The presence of T o x o p l m a gondii in dasyurid marsupials has now been proven morphologically, serologically and by animal passage, Of the 240 animals examined (12 Antechinomys spenceri, 9 Antechinus apicalis, 14 Anrechinus macdonnellensis, 21 Antechinus stuartii, 51 Dasycercus cristicauda, 107 Dasyuroides bymei, 7 Sminrhopsis crassicaudata, 2 Sminthopsis Iarapinta and 17 Sminthopsis leucopus) a preponderance of involvement of brain, spinal cord and heart has been shown. Endemic infection in Dasyuroides byrnei has been proved, but there is good evidence for infection within the laboratory which is probably caused by their diet of raw sheeps’ heart, brain and liver. Infection has never been demonstrated in animals less than 6 mth of age. The 21 Antechinus stuarrii examined have remained entirely free from infection despite a lengthy stay in the laboratory and a similar diet. This freedom from infection may be indicative of a specific resistance to infection by this one species of the Dasyuridae. STANDARDIZATION AND METHODS FOR PROFICIENCY TESTING I N HISTOPATHOLOGY AND CYTOLOGY
BARGER, J. D. Sunrise Hospital, L a Vegas, Nevada, U S A The origins and development of an investigational programme inquiring into the feasibility of developing proficiency testing in histopathology and cytopathology similar to programmes in clinical pathology i s presented. Problems of semantics, design of the surveys and their evaluation present difficult problems which have been partially solved. VITAMIN A SOLUBILITY I N MICELLAR SOLUTIONS
BARKER, A. N. Department of Clinical Chemistry, Auckland Hospital, New Zealand
Absorption of vitamin A is impaired in pancreatic insufficiency. It has been suggested that absorption of vitamin A is dependent on its solubility in the aqueous micellar phase of the duodenal contents. Vitamin A is said to be virtually insoluble in pure bile salt micelles, but readily soluble in mixed micelles which have been expanded by the incorporation of monoglycerides and fatty acids. In pancreatic insufficiency these products of fat hydrolysis are present in low concentration, and so mixed micelle formation is greatly reduced. Vitamin A solubility is possibly further reduced by the partitioning effect between the aqueous micellar phase and the increased oil phase present in this condition. Experiments were performed to demonstrate the solubility of vitamin A in both pure and mixed micellar solutions, and the effect of the presence of an oil phase. It was shown that vitamin A is significantly soluble in pure micellar solutions, and that the expansion of the micelle by monoolein or oleic acid has only a limited effect on solubility. It was also shown that the addition of an oil phase has a dramatic effect on lowering the micellar solubility of vitamin A. I t is proposed that the partitioning of vitamin A into the excessive oil phase present in pancreatic insufficiency is a more important mechanism for the malabsorption of vitamin A than the absence of a mixed micellar phase.
T H E ROYAL COLLEGE OF PATHOLOGISTS O F AUSTRALIA
prepared for light microscopy and stained by the following methods : H & E, PAS, PAS-diatase, PTAH, Masson’s trichrome, Connor’s crystal violet-acid fuchsin, Puchler’s PAS-tannic acid-phosphomolybdic acid-levanol fast cynanine 5RN, Lie’s haematoxylin-basic fuchsin-picric acid. Following 40 min-2 h of arterial occlusion or autolysis, affected tissue showed a loss of glycogen which was recognizable in PASor Puchtler-stained sections. From 2 h onward the myofibres of infarcted tissue showed structural alterations detectable with H & E but were more clearly shown by PTAH, Connor’s, Putchtler’s and Masson’s stains. After 6 or more h of arterial Qcclusion the infarcted tissue was clearly defined in all preparations by neutrophil infiltration. Lie’s stain, which is said to produce a specific general colour reaction in infarcted tissue, gave inconsistent results and the differentiation time was extremely critical. Thus, although staining by Puchtler’s technique appears to be the most valuable method for determining the presence and age of early experimental infarcts, its application to human autopsy material is limited by the glycogen depletion which occurs during autolysis. TOXOPLASMOSIS IN DASYURID MARSUPIALS : A FINAL CHAPTER
ATTWOOD,H. D. and WOOLLEY, P. A,, Department of Pathology, University of Melbourne, Deparrment of Zoology, La Trobe University, Victoria
The presence of T o x o p l m a gondii in dasyurid marsupials has now been proven morphologically, serologically and by animal passage, Of the 240 animals examined (12 Antechinomys spenceri, 9 Antechinus apicalis, 14 Anrechinus macdonnellensis, 21 Antechinus stuartii, 51 Dasycercus cristicauda, 107 Dasyuroides bymei, 7 Sminrhopsis crassicaudata, 2 Sminthopsis Iarapinta and 17 Sminthopsis leucopus) a preponderance of involvement of brain, spinal cord and heart has been shown. Endemic infection in Dasyuroides byrnei has been proved, but there is good evidence for infection within the laboratory which is probably caused by their diet of raw sheeps’ heart, brain and liver. Infection has never been demonstrated in animals less than 6 mth of age. The 21 Antechinus stuarrii examined have remained entirely free from infection despite a lengthy stay in the laboratory and a similar diet. This freedom from infection may be indicative of a specific resistance to infection by this one species of the Dasyuridae. STANDARDIZATION AND METHODS FOR PROFICIENCY TESTING I N HISTOPATHOLOGY AND CYTOLOGY
BARGER, J. D. Sunrise Hospital, L a Vegas, Nevada, U S A The origins and development of an investigational programme inquiring into the feasibility of developing proficiency testing in histopathology and cytopathology similar to programmes in clinical pathology i s presented. Problems of semantics, design of the surveys and their evaluation present difficult problems which have been partially solved. VITAMIN A SOLUBILITY I N MICELLAR SOLUTIONS
BARKER, A. N. Department of Clinical Chemistry, Auckland Hospital, New Zealand
Absorption of vitamin A is impaired in pancreatic insufficiency. It has been suggested that absorption of vitamin A is dependent on its solubility in the aqueous micellar phase of the duodenal contents. Vitamin A is said to be virtually insoluble in pure bile salt micelles, but readily soluble in mixed micelles which have been expanded by the incorporation of monoglycerides and fatty acids. In pancreatic insufficiency these products of fat hydrolysis are present in low concentration, and so mixed micelle formation is greatly reduced. Vitamin A solubility is possibly further reduced by the partitioning effect between the aqueous micellar phase and the increased oil phase present in this condition. Experiments were performed to demonstrate the solubility of vitamin A in both pure and mixed micellar solutions, and the effect of the presence of an oil phase. It was shown that vitamin A is significantly soluble in pure micellar solutions, and that the expansion of the micelle by monoolein or oleic acid has only a limited effect on solubility. It was also shown that the addition of an oil phase has a dramatic effect on lowering the micellar solubility of vitamin A. I t is proposed that the partitioning of vitamin A into the excessive oil phase present in pancreatic insufficiency is a more important mechanism for the malabsorption of vitamin A than the absence of a mixed micellar phase.