Indium-111-white blood cell detection of postradiation vesicocutaneous fistulas.

We present a case of urinary bladder fistulization which occurred approximately 25 yr after successful radiation therapy for uterine carcinoma. The extensive fistulas were detected with 111In-oxine-labeled white blood cell scintigraphy and were confirmed with a fistulogram, computed tomography and surgery. Scintigraphy was valuable for both initial detection as well as staging the extent of inflammation for subsequent diagnostic studies and surgical resection.

Hyperbaric hyperoxia reversibly inhibits erythrocyte phospholipid fatty acid turnover.

The present study is one component of a comprehensive investigation of oxygen tolerance of tissues and organs in normal human subjects. The focus of this study was the acylation of membrane phospholipid in situ by erythrocytes. Activation of exogenous [9,10-3H]oleic acid to acyl thioester and transesterification of the acyl thioester into phospholipid by intact human erythrocytes incubated in vitro decreased 30% after exposure of 10 human subjects to hyperbaric hyperoxia (100% O2, 3 ATA, 3.5 h). Partial recovery of activity could be detected when additional cells were obtained from these subjects and assayed in vitro 24 h after cessation of exposure. No significant change in membrane phospholipid fatty acid composition was detected under these conditions. The reduced glutathione content of intact erythrocytes increased by 15% after hyperbaric hyperoxia and remained elevated 24 h after exposure. In isolated membranes prepared from the same cells activation of [9,10-3H]oleic acid to acyl thioester and its transesterification into phospholipid did not change after hyperoxia. Since the ability of intact cells to replace oxidized fatty acids in membrane phospholipids via deacylation and reacylation in situ may be necessary for the maintenance of membrane integrity during exposure to oxidative stress, the decrease in [9,10-3H]oleic acid incorporation by human erythrocytes detected in vitro after hyperbaric hyperoxia in vivo may reflect an early event in the pathogenesis of oxygen-induced cellular injury and may be a useful index for assessment of the tolerance of tissues to hyperoxia.

Placental changes in fetal triploidy syndrome.

The sonographic findings in fetal triploidy syndrome include intrauterine growth retardation, hydrocephalus, oligohydramnios, and hydropic changes of the placenta. Ultrasonography can establish the diagnosis only when placental findings coexist with a fetus. Although the majority of triploid conceptions abort spontaneously in the first trimester, occasionally they will progress further, but rarely to term. Six cases are presented in which the diagnosis was suspected by early ultrasound examinations, including one case in which there was an unusually large trophoblastic cyst. Determination of the karyotype is important for the management of a pregnancy with a live fetus, and has implications for genetic counseling of subsequent pregnancies.

t-Butyl hydroperoxide alters fatty acid incorporation into erythrocyte membrane phospholipid.

Because the ability of cells to replace oxidized fatty acids in membrane phospholipids via deacylation and reacylation in situ may be an important determinant of the ability of cells to tolerate oxidative stress, incorporation of exogenous fatty acid into phospholipid by human erythrocytes has been examined following exposure of the cells to t-butyl hydroperoxide. Exposure of human erythrocytes to t-butyl hydroperoxide (0.5-1.0 mM) results in oxidation of glutathione, formation of malonyldialdehyde, and oxidation of hemoglobin to methemoglobin. Under these conditions, incorporation of exogenous [9,10-3H]oleic acid into phosphatidylethanolamine is enhanced while incorporation of [9,10-3H]oleic acid into phosphatidylcholine is decreased. These effects of t-butyl hydroperoxide on [9,10-3H]oleic acid incorporation are not affected by dissipating transmembrane gradients for calcium and potassium. When malonyldialdehyde production is inhibited by addition of ascorbic acid, t-butyl hydroperoxide still decreases [9,10-3H]oleic acid incorporation into phosphatidylcholine but no stimulation of [9,10-3H]oleic acid incorporation into phosphatidylethanolamine occurs. In cells pre-treated with NaNO2 to convert hemoglobin to methemoglobin, t-butyl hydroperoxide reduces [9,10-3H]oleic acid incorporation into phosphatidylcholine by erythrocytes but does not stimulate [9,10-3H]oleic acid incorporation into phosphatidylethanolamine. Under these conditions oxidation of erythrocyte glutathione and formation of malonyldialdehyde still occur. These results indicate that membrane phospholipid fatty acid turnover is altered under conditions where peroxidation of membrane phospholipid fatty acids occurs and suggest that the oxidation state of hemoglobin influences this response.

Diagnosis of pulmonary amyloidosis by transbronchial biopsy.

Previously reported cases of pulmonary parenchymal amyloidosis were diagnosed by open lung biopsy or postmortem examination. We describe 3 patients who were found to have amyloid deposits within the lung parenchyma by flexible fiberoptic bronchoscopy. In each case, the diagnosis was suspected when a waxy eosinophilic substance was observed within the alveolar walls of transbronchial biopsy specimens stained with hematoxylin-eosin. When stained with Congo red and examined under polarized light, this amorphous material exhibited the apple-green birefringence characteristic of amyloid fibrils. We suggest that a diagnosis of pulmonary amyloidosis can be made by transbronchial biopsy provided the appropriate histologic stains are employed. Special stains for amyloid should be obtained whenever histologic sections from transbronchial biopsy specimens reveal amorphous eosinophilic material within the alveolar septa or within the walls of small vessels.

Preparation of inside-out vesicles from erythrocyte membranes inactivates the pathway for oleic acid incorporation into phospholipid.

The pathway for membrane phospholipid fatty acid turnover in situ may be important in the regulation of the composition and turnover of the lipid microenvironment of membrane proteins. This pathway has been characterized further by studying the activation and incorporation of [9,10(n)-3H]oleic acid and transesterification of [1-14C]oleoyl-CoA into membrane phospholipids by isolated erythrocyte membrane ghosts and inside-out vesicles derived from these ghosts. Erythrocyte ghosts and sealed vesicles of defined orientation prepared from them have been widely employed in studies of the function of membrane proteins, particularly those which mediate the transport of ions and sugars. Preparation of inside-out vesicles from ghosts by exposure to alkaline hypotonic conditions results in elution of some membrane proteins but no loss of membrane phospholipid. Compared to ghosts, the ability of inside-out vesicles to activate and incorporate [9,10(n)-3H]oleic acid into phospholipid is diminished by over 90% and the ability of inside-out vesicles to transesterify [1-14C]oleoyl-CoA to phospholipid is diminished by over 50%. These findings indicate that exposure of erythrocyte membranes to the alkaline hypotonic conditions required for inside-out vesicle preparation results in loss or inactivation of both acyl-CoA ligase and acyl-CoA-lysophospholipid acyltransferase activities. This lability of the enzymes for in situ phospholipid fatty acid turnover should be considered in the design and interpretation of studies concerned with elucidation of the relationship between phospholipid fatty acid turnover and the regulation of membrane protein function in this membrane preparation.

The relationship between valinomycin-induced alterations in membrane phospholipid fatty acid turnover, membrane potential, and cell volume in the human erythrocyte.

The relationship between alterations in transmembrane potential, cell volume, and phospholipid fatty acid turnover has been examined in human erythrocytes by treating the cells with the monovalent cation ionophore valinomycin. Valinomycin increases the cellular uptake of tetra[3H]phenylphosphonium ion by erythrocytes, indicating membrane hyperpolarization, and causes net loss of potassium chloride and water from the cells leading to a decrease in cell volume. Treatment of erythrocytes with valinomycin also enhances incorporation of [9, 10-(3)H]oleic acid into phospholipids, primarily diacylphosphatidylethanolamine. After replacing intracellular chloride with sulfate and treating cells with the anion transport inhibitor 4,4'-diisothiocyanostilbene-2,2'-disulfonate, exposure to valinomycin results in uptake of tetra[3H]phenylphosphonium ion and stimulation of [9, 10-(3)H]oleic acid incorporation, but, because anion efflux is prevented, no decrease in cell volume occurs. When tetra[3H]phenylphosphonium ion uptake is also prevented by suspending these cells in 125 mM KCl to dissipate the transmembrane potassium gradient, valinomycin still enhances [9, 10-(3)H] oleic acid incorporation into phospholipid. These results suggest that the presence of valinomycin in the membrane directly alters phospholipid fatty acid turnover and that some of the effects of this ionophore on cellular function previously attributed to alterations in transmembrane potential or cellular potassium content may instead be due to altered phospholipid turnover. Since it is possible that valinomycin may directly perturb phospholipid fatty acid turnover in other cells, the possibility that valinomycin-induced alterations in cellular function are due to altered phospholipid turnover rather than membrane hyperpolarization or altered potassium content should be considered in the interpretation of studies employing this ionophore.

Normobaric hyperoxia in vivo inhibits fatty acid incorporation into sheep erythrocyte phospholipid in vitro.

Oxygen toxicity is a major complication of normobaric hyperoxia in therapeutic settings. Because alterations in membrane function occurring as a consequence of peroxidation of membrane phospholipid fatty acids may be an early event in the pathogenesis of oxygen-induced injury, we studied the effects of hyperoxia on the ability of the membrane to repair itself by incorporating fatty acid via the pathway for deacylation and reacylation in situ. Although the lung is the major site of clinically significant injury, the erythrocyte is also directly exposed to elevated PO2 in vivo. In this study, incorporation of [9,10(-3)H]-oleic acid into phospholipid has been measured in sheep erythrocytes in vitro after exposure of four animals to normobaric hyperoxia in vivo. [9,10(-3)H]-Oleic acid incorporation into erythrocyte phospholipid decreased within 24 hours and reached 50% of pre-exposure levels after 70 hours of exposure to 100% O2. No significant change in the fatty acid composition of membrane phospholipid was detected under these conditions. In contrast to the results with intact cells, incorporation of [9,10(-3)H]-oleic acid into phospholipid by isolated erythrocyte membranes prepared from the cells of two animals increased after 70 hours of exposure to 100% O2, indicating that the inhibition of fatty acid incorporation in intact erythrocytes does not result from irreversible inactivation of the enzymes involved in acylation of endogenous lysophospholipid. Because the ability of cells to replace membrane phospholipid fatty acids via deacylation and reacylation in situ could be important in the maintenance of membrane integrity during oxidative stress, the decrease in fatty acid incorporation by erythrocytes in vitro may reflect an early event in the pathogenesis of oxygen-induced cellular injury.

Melanin production in a medullary thyroid carcinoma.

Melanin production by a medullary thyroid carcinoma (MTC) is reported and discussed. Immunohistochemically, the tumor cells contained calcitonin; by electron microscopy, they bore numerous, heterogeneous granules similar to those described previously in MTCs. One small focus of tumor was pigmented. Here, melanosomes in different stages of maturation were found in dendritic cells that ramified among granule-bearing cells. The remarkable phenotypic divergence in this solitary, nongerm cell neoplasm is unusual but not so surprising in light of the APUD nature and neural crest origin of both the melanocyte and the thyroid C cell, which gives rise to MTC. The authors view the calcitonin and melanosome phenotypes as closely related tumor clones evolving from a common precursor neoplastic cell. This unique "experiment of nature" adds to the set of rare human tumors that make melanin "ectopically."

Direct interaction of mepacrine with erythrocyte and platelet membrane phospholipid.

Mepacrine has been used as an inhibitor of the activation of endogenous phospholipases in many systems. These endogenous phospholipases are important in the modification of the lipid environment of membrane proteins and in the release of locally active oxygenated arachidonic acid metabolites. In both human platelets and erythrocytes, mepacrine blocks the release of fatty acid from phospholipid by endogenous phospholipases. However, mepacrine also interacts directly with membrane phospholipids, primarily phosphatidylethanolamine, to form less polar derivatives. This interaction occurs rapidly and is maximal at concentrations of mepacrine greater than 0.2 mM. Such drug-phospholipid interaction may perturb membrane architecture and function and be responsible for the inhibitory effects of mepacrine on cellular responses observed in many systems. Since the alteration in membrane phospholipid composition occurs under the same conditions as phospholipase inhibition, it is not possible to be certain that the inhibition of cellular responses by mepacrine is due to inhibition of phospholipases rather than to direct perturbation of the membrane. It is also possible that inhibition of phospholipase action by mepacrine is in part a consequence of the change in phospholipid composition. These results indicate that caution should be exercised in the interpretation of results obtained using mepacrine and that the usefulness of this compound for the investigation of the biological importance of phospholipase activation is limited.

Elastofibroma dorsi: an immunochemical study of collagen content.

The types of collagen present in a case of elastofibroma dorsi were determined using type specific, characterized collagen antibodies. The presence of type II collagen (normally present only in articular cartilage and in selected ocular structures) is discussed with regard to the pathogenesis of this lesion, and the use of collagen antibodies is discussed with regard to their potential value in better characterizing and classifying mesenchymal tumors.

Selective stimulation of erythrocyte membrane phospholipid fatty acid turnover associated with decreased cell volume.

Treatment of erythrocytes with the divalent cation ionophore A23187 results in net uptake of calcium and a calcium-dependent decrease in cellular potassium content and cell volume. These changes in membrane properties are associated with a selective stimulation of fatty acid incorporation into membrane phosphatidylethanolamine (PE). In this study the relationship between this selective stimulation of phospholipid fatty acid turnover and changes in calcium uptake, cellular potassium content, and cell volume has been examined by 1) preventing the calcium-dependent loss of potassium without abolishing calcium uptake and 2) altering cellular potassium content and cell volume without increasing net uptake of calcium by utilizing the monovalent cation inonophore nigericin or increasing the osmolarity of the buffer. It has been shown that treatment of erythrocytes with A23187, nigericin, or hypertonic buffer results in a selective stimulation of fatty acid incorporation into PE. These results suggest that a mechanical or conformational change in the membrane is associated with a selective stimulation of fatty acid turnover in phosphatidylethanolamine.

Definition of the pathway for membrane phospholipid fatty acid turnover in human erythrocytes.

Techniques have been developed to permit detection of acyl thioesters derived from exogenous fatty acids in erythrocytes. These acyl thioesters have been shown to act as intermediates in the acylation of endogenous lysophospholipid. Release of fatty acids from erythrocyte phospholipids has also been detected. Such release reflect the activity of an endogenous phospholipase that utilizes endogenous phospholipid as substrate. These observations permit further definition of the biochemical pathway for erythrocyte phospholipid fatty acid turnover.

Calcium-dependent stimulation of erythrocyte membrane phospholipid fatty acid incorporation by the ionophore A23187.

Treatment of human erythrocytes with A23187, a divalent cation ionophore, results in a calcium-dependent increase in the rate of incorporation of palmitic, oleic, and linoleic acids into phosphatidylethanolamine. Incorporation of fatty acids into phosphatidylcholine is unaffected by A23187. This calcium-dependent stimulation of membrane phosphatidylethanolamine fatty acid turnover by A23187 may be related to the changes in erythrocyte membrane function induced by A23187 that have been observed previously.