The microfilaments in the acinar cell of the exocrine pancreas are essentially located in the apical part of the cell: thin microfilaments (50 A), cytochalasin B (CB)-sensitive, form the axis of the microvilli and a network lying beneath the apical membrane; thicker filaments (100 A), at least partly CB-insensitive, form bundles parallel to the plasma cell membrane and the desmosomal links. CB interaction with the acinar cell of the exocrine pancreas involves at least two sites: a membrane site involved in the inhibitory effect of CB on the monosaccharide transport and a less sensitive site at the filamentous level at least partly responsible for the inhibitory effect of CB in the secretion of the exportable enzyme from the pancreatic cell. CB did not alter the energy balance of the acinar cell nor the exchanges of 45Ca between the extracellular medium and the pancreatic tissue. CB (2 x 10 -7 and 2 x 10 -6 M) has secretagogue properties whereas CB (2 • 10 -s M) has inhibitory effect on stimulated secretion and secretagogue properties. The mechanism of these secretory effects is not yet explained. The analysis presented in this investigation affords strong evidence for the involvement of the microfilamentous network in the last steps of the secretory cycle in the acinar cell of the exocrine pancreas.
The capacity of certain fatty acids at pH 7.5 to inactivate the virus of epidemic influenza has been demonstrated. Most effective of these are oleic, linolic, and linolenic acids.
Studies were made of such variables as pH, rate of inactivation, and ratios of reactant concentrations, using oleic acid as a prototype of the effective acids. Attempts to recover active virus from inactive mixtures by decrease in pH, dialysis, dilution, or addition of calcium chloride solution to inactivated virus have been unsuccessful.
The stability of virus at different hydrogen ion concentrations has been determined.
Quantitative comparisons have been made of the immunizing capacity of fully active virus and virus rendered non-infectious by treatment with oleic acid. It was found that while the infectious property of the virus is removed the immunogenic capacity is essentially unaltered.
The possible mechanism by which the soaps act upon influenza virus has been discussed.
The reliability of lipid‐bound sialic acid (LSA) as a marker in breast cancer was evaluated in 78 normal subjects, 106 patients with benign breast disease, 64 patients with primary operable breast cancer, and 61 patients with recurrent metastatic breast cancer. LSA levels were determined before and after mastectomy and during chemotherapy in selected patients to determine the value of LSA in monitoring therapy and predicting response. LSA levels greater than 20 mg/dl were not seen in normal subjects but were present in patients with benign breast disease (13%), primary breast cancer (47%) and recurrent metastatic breast cancer (62%). LSA levels decreased after initiation of chemotherapy and remained low in patients clinically disease‐free. Recurrences were associated with elevated LSA in patients failing chemotherapy or endocrine ablative surgery. LSA measurements appeared to be of limited value in the detection of breast cancer but serial measurements may be useful in assessing disease progression and identifying patients resistant to therapy. Cancer 50:1815‐1819, 1982.
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