Biomedical subjects

D H Kruse

Publications and source records attributed to D H Kruse.

13 recordsLinked to original sources

PubMed2002

An enzyme histochemical and biochemical study of the activity of three oxidative enzymes in the developing rat parotid gland.

Information on ductal differentiation in the developing rat parotid gland is sparse. One of the main functions of the striated and excretory ducts in this gland is the selective exchange of electrolytes from the primary fluid secreted by the acini. These ducts are rich in a number of enzymes involved in this task, suggesting that they might be useful as markers of ductal differentiation. The objective of this investigation was to delineate the developmental changes in activity of three of these, cytochrome C oxidase (CCO), succinate dehydrogenase (SDH), nicotinamide adenine phosphate dinucleotide (reduced form)-dehydrogenase (NADPH-DH). Histochemical localization of all three enzymes in fresh frozen sections was complemented by biochemical assays of CCO and SDH and cytochemical localization of CCO. Biochemically, CCO- and SDH-specific activity in gland homogenates increased progressively after birth, reaching adult levels at 21-28 days. Histochemically, deposits of reaction products of all three enzymes increased more in the striated and excretory ducts, especially in their basal cytoplasm, than in other glandular structures between 19 days in utero and 28 days after birth. During the same age span, the mitochondria in the striated and excretory ducts increased markedly in both number and size, migrated to a mostly basal location, and increased from many to virtually all showing strong cytochemical CCO reactions. These histochemical and cytochemical patterns of changes in enzyme activity at the cellular level accounted for the overall increases in CCO and SDH seen in the biochemical assays. Only the SDH histochemical reaction was consistently weak in the acini and intercalated ducts, and thus provided the most contrast with the progressively stronger reactions in the larger ducts. We conclude that of the three enzymes evaluated in these experiments, SDH is the best marker of the functional differentiation of the striated and excretory ducts in the developing rat parotid gland.

Animals↗

PubMed2001

Immunohistochemical localization and mRNA detection of Rab3D and/or Rab3B in rat von Ebner's glands, parotid gland, pancreas, and liver.

In examining the secretory mechanism of exocrine glands, we focused on the small GTP-binding proteins, Rab3D and Rab3B, which function in the final steps of exocytosis in non-neuronal tissues. These proteins were observed in von Ebner's glands by 32P-GTP overlay. mRNA isolated from von Ebner's glands, the pancreas, parotid glands, and liver was subjected to reverse transcription PCR and probed with primers and nested primers for Rab3D and Rab3B. Rab3D was found in all three exocrine glands and the liver, while Rab3B was found in the liver. Utilizing immunofluorescence histochemistry, Rab3D was localized to hepatocytes of the liver and to secretory granules of the exocrine glands, and Rab3B to liver and pancreatic islets. Isoproterenol evoked decreases in alpha-amylase- and Rab3D-labelled parotid secretory granules, and pilocarpine stimulated decreases in secretory granules labelled for lingual lipase and Rab3D from von Ebner's glands, and amylase and Rab3D from pancreas. Neither secretagogue affected Rab3B in pancreatic islets. These observed parallel decreases in response to beta-adrenergic (parotid) or cholinergic (von Ebner's and pancreas) secretagogues indicate that the function of Rab3D in exocytosis in these exocrine organs is similar and that the type of secretagogue does not determine the function.

Animals↗

PubMed1998

Enzyme histochemical and immunohistochemical localization of carbonic anhydrase as a marker of ductal differentiation in the developing rat parotid gland.

BACKGROUND: Carbonic anhydrase has been localized to the acini and ducts of mature rat parotid glands. This enzyme has been associated with ion transport, a prominent function of striated and excretory ducts in salivary glands, suggesting that it might be used as a marker of ductal differentiation. The purpose of this study was histochemically to document developmental changes in carbonic anhydrase in the ducts of the rat parotid gland. METHODS: Parotid glands were excised from rats at representative developmental ages. Enzyme histochemistry was done on frozen sections fixed in acetone, and immunohistochemistry was performed with antibodies to human carbonic anhydrase isoenzymes I, II, and VI on paraffin sections of glands fixed in Helly's fluid. RESULTS: Carbonic anhydrase activity was weak until age 21 days after birth, when it had increased slightly in the acini and intercalated ducts and moderately in striated and excretory ducts. The adult pattern was attained by 28 days, in which reactions were moderate to strong in the striated and excretory ducts and modest in the acini and intercalated ducts. Immunohistochemical reactions were weak until 14 days, then increased rapidly, and by 28 days approached the adult pattern of virtually none in the acini and modest to moderately strong in the striated and excretory ducts. The order of reaction intensity of the antibodies was II > I > VI. CONCLUSIONS: Carbonic anhydrase is a useful marker of the functional differentiation of the striated and excretory ducts of the developing rat parotid gland.

Animals↗

PubMed1998