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M B Thompson

Publications and source records attributed to M B Thompson.

69 records · Page 4Linked to original sources
PubMed1986

Magnetic resonance microscopy in neurologic models.

Magnetic resonance imaging techniques have been developed to permit imaging with slice thickness less than 1 mm and pixels of 50 x 50 microns. Special purpose gradient and radiofrequency coils and three-dimensional imaging techniques enable acquisition of images with sufficient signal to noise to utilize these microscopic picture elements. Live 200 g rats were imaged enabling clear definition of gray and white matter structures. Examples include the Sylvian aqueduct and the substantia nigra. Three-dimensional microscopic images of live chick embryos enabled definition of ventricles and brain parenchyma as well as measurement of T1 over the set of 16 contiguous 1.2 mm slices.

Animals↗
PubMed1984

Polyethylene glycol-6000 as a clearing agent for lipemic serum samples from dogs and the effects on 13 serum assays.

Polyethylene glycol-6000 (PEG) was evaluated as a clearing agent for lipemic serum from dogs. Effects of PEG-treatment in lipemic and non-lipemic samples were determined for 13 chemical and enzymatic assays (glucose, BUN, alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, amylase, total protein, albumin, sodium, potassium, chloride, phosphorus, and calcium). Control samples for lipemic sera were prepared by ultracentrifugation. Treatment with PEG cleared all lipemic samples. Regression lines for all lipemic samples were highly significant (P less than 0.0001) and the SD of the control values around the regression lines were small compared with the mean value for an assay. The technique was simple, quick, and inexpensive. With proper validation, reliable predictions of true serum values could be calculated for lipemic serum samples for all assays studied.

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PubMedDate not supplied

Nutrient uptake by embryos of the Australian viviparous lizard Eulamprus tympanum.

Eulamprus tympanum is a high-altitude viviparous lizard that was probably used to help define a Type I chorioallantoic placenta. In this article, we (1) describe the net transport of nutrients across the placenta of E. tympanum, and (2) compare placental uptake in E. tympanum with a previous study of Eulamprus quoyii, which occurs in warmer environments, to assess the potential importance of thermal regime on placentotrophy. Freshly ovulated eggs are 387.3+/-19.7 mg. There is a significant net uptake of water and a net loss of dry matter during development, so the dry neonate is only 84% the size of the dry egg. There is no significant change in the total ash or nitrogen in eggs during embryonic development, with the entire loss of dry matter being lipid. Almost the entire loss of lipid occurs in the triacylglycerol fraction, with no net change in phospholipids. A net increase in total cholesterol suggests that cholesterol is synthesised by the developing embryo. The lipid profile of eggs of E. tympanum reflects that of other species with simple placentae in having a relatively high proportion of triacylglycerol and little cholesterol. The fatty acid composition of eggs reflects that expected in the diet of E. tympanum. There is a preservation and some synthesis of arachidonic (20:4n-6) and docosahexaenoic (22:6n-3) acids in the phospholipid fraction during embryonic development. Despite there being no net uptake of ash, there is a net increase in calcium, potassium, sodium, and magnesium in the neonate compared with the egg. We conclude that E. tympanum, like E. quoyii, is predominantly lecithotrophic with little, if any, uptake of organic molecules but with significant uptake of some inorganic ions and water. In addition, there is no difference in placentotrophy correlated with differences in the environments inhabited by each species.

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PubMedDate not supplied

Use of ursodeoxycholic acids in a dog with chronic hepatitis: effects on serum hepatic tests and endogenous bile acid composition.

A dog with severe cholestasis secondary to chronic hepatitis was treated with ursodeoxycholic acid (UDCA) PO. After 2 weeks of daily treatment, the dog was more active and had an improved appetite. Monthly serum biochemical determinations and analysis of individual bile acid profiles documented improvement in hepatobiliary tests and a marked reduction in the concentrations of potentially hepatotoxic endogenous bile acids. These effects were maintained for approximately 6 months. The findings in this dog are similar to those reported for human patients treated with UDCA and provide preliminary evidence in support of its continued evaluation in the treatment of cholestatic liver disease in the dog.

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PubMedDate not supplied

Paracoccidioides brasiliensis in a postpartum Pap smear. A case report.

BACKGROUND: There are several reported cases that describe female genital tract infections with opportunistic fungi, such as Blastomyces dermatitidis, Coccidioides immitis, Aspergillus flavus, Cryptococcus neoformans and Mucor. We describe a case of paracoccidiodomycosis limited to the uterine cervix. To the best of our knowledge, no such case has been described before in the English-language literature. CASE: A 27-year-old, healthy female, gravida 3, para 2, abortion 1, presented for a routine gynecologic examination at six weeks' postpartum. Her past medical history was unremarkable. A routine cervical/endocervical smear revealed the presence of multiple fungal forms at different stages of development with a characteristic "pilot's wheel" appearance consistent with Paracoccidioides brasiliensis. Detailed medical examination of the patient did not reveal the presence of the primary infection in any other system. Cultures of the endometrium revealed no growth of the fungal organisms. The patient was asymptomatic, and therefore no therapy was initiated. Repeat Papanicolaou smears were negative for organisms. CONCLUSION: Paracoccidioidomycosis can present as a limited form, involving the cervix only. Identification and recognition of the infection are important in cytopathology.

Adult↗
PubMedDate not supplied

Bile acids in the assessment of hepatocellular function.

Bile acids, which are synthesized in the liver from cholesterol, are important in the production of bile flow, excretion of cholesterol, and intestinal digestion and absorption of fats and fat-soluble vitamins. Increases and/or alterations in concentrations of bile acids in serum are specific and sensitive indicators of hepatobiliary disorders. Synthesis of bile acids in hepatocytes involves steps in endoplasmic reticulum, cytosol, mitochondria, and peroxisomes. Other important hepatocellular processes involving bile acids include active uptake by the basolateral membrane, intracellular transport, P-450-mediated conjugations and hydroxylations, and canalicular secretion. Hydrophobic bile acids produce hepatotoxicity in vivo and in vitro. In experimental and epidemiologic studies, some of these forms have been identified as causative agents in the development of colon and liver (experimental only) cancer. Conversely, several hydrophilic forms, primarily ursodeoxycholic acid, have demonstrated cytoprotective properties in a variety of clinical and experimental hepatobiliary diseases and disorders. Because bile acids can have dramatically different properties and effects, determination of mechanisms of action of these compounds has become an active area of research. Primary isolated hepatocytes provide an opportunity to investigate bile acid-related functions and effects in well-designed, carefully controlled studies. Short-term cultures have been used to study a variety of issues related to bile acids, including cytotoxicity, synthesis, and hepatocellular processing. With these systems, however, many functions of mature hepatocytes, including those pertaining to bile acids, can be lost when cultures are maintained for more than several days. Recent developments in culture techniques permit long-term maintenance of functionally stable, differentiated cells. Pertaining to bile acid research, these systems remain to be fully characterized but, in appropriate situations, they should provide important alternatives to in vivo studies and short-term in vitro assays.

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PubMedDate not supplied

Fine needle aspiration cytology of lymphoepitheliomalike carcinoma of the parotid gland. A case report.

Lymphoepitheliomalike carcinoma is a rare primary neoplasm of the salivary gland that has also been reported to occur in other primary sites. In this report we document the clinical, cytomorphologic and histologic findings of a case affecting the parotid gland. The patient was a 48-year-old, white woman with a two-month history of a swelling on the left side of the face and associated pain. Physical examination and computed tomography revealed a left parotid mass with spread to the superior cervical lymph nodes. Fine needle aspiration (FNA) of the parotid and upper cervical nodes revealed multiple, irregular aggregates of epithelial cells with a high nuclear/cytoplasmic ratio and finely granular chromatin. Prominent, single, round nucleoli were present. Multiple chromocenters were also noted. These aggregates were found in a background of abundant, benign, small and large lymphocytes. The patient underwent parotidectomy with radical neck dissection. Histopathologic examination of the parotid showed a poorly differentiated carcinoma in a benign lymphoid background consistent with lymphoepitheliomalike carcinoma, with metastatic tumor involving two lymph nodes of the parotid compartment. To our knowledge, this is the first reported case of FNA biopsy of this unusual entity. The cytomorphologic features of these neoplasms when aspirated from the salivary gland are sufficiently distinctive to allow a specific diagnosis of lymphoepitheliomalike carcinoma.

Biopsy, Needle↗
PubMedDate not supplied

Placental ontogeny of the Australian scincid lizards Niveoscincus coventryi and Pseudemoia spenceri.

Models for the evolution of placentation among squamate reptiles have been strongly influenced by early work on one lineage of Australian scincid lizards: one of three lineages that include species with specialized allantoplacentation. The discovery of two types of complex allantoplacentae among species currently assigned to the Eugongylus species group led Weekes ([1935] Proc. Zool. Soc. Lond., 2:625-645) to propose that a graded evolutionary sequence was exemplified by the morphological series of allantoplacental types that existed among Australian skinks. One of the model's strengths is the incorporation of testable inferences of the relationship between placental structure and function. However, descriptions of placental structure for some species are incomplete and subsequent taxonomic revisions have resulted in confusion concerning the species studied. One of the ambiguities is the identity of Lygosoma weekesae (Kinghorn [1929] Proc. Linn. Soc. N.S.W., 54:32-33), one of two species for which the most specialized type of allantoplacenta was defined. The distinguishing characteristic of this placental type is the presence of a structure known as a placentome. Subsequent to the original species description, Lygosoma weekesae was named a synonym for Pseudemoia spenceri (Rawlinson [1974] Mem. Natn. Mus. Vict., 35:87-96), yet the placental description (Weekes [1929] Proc. Linn. Soc. N.S.W., 54:34-60) is thought to be of Niveoscincus coventryi (Rawlinson [1975] Mem. Natn. Mus. Vic., 36:1-16). We describe placental ontogeny of N. coventryi and P. spenceri as a contribution to study of comparative placentation among lygosomatine skinks. We conclude that the placental description for L. weekesae could not have been N. coventryi, because a placentome is not a component of the allantoplacenta of N. coventryi. Further, the allantoplacenta of this species does not conform to previously defined categories for Eugongylus group skinks. The allantoplacenta of P. spenceri contains a placentome that is structurally congruous with the original description of placentation for L. weekesae (Weekes [1929] Proc. Linn. Soc. N.S.W., 54:34-60). Comparison of extraembryonic membrane and placental structure among the four viviparous and one oviparous species of Eugongylus group skinks for which data are available shows that each species exhibits characters that distinguish it from other species, while additional characters are shared among all, or some, species. Based on a recent phylogenetic hypothesis, the distribution of allantoplacental types among these species does not support Weekes' ([1935] Proc. Zool. Soc. Lond., 2:625-645) model of a graded sequence for the evolution of squamate placentation.

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