Showing papers by "University of Maryland, Baltimore published in 1978"

Trabecular carcinoma of the skin. An ultrastructural study

Abstract: We report the electron microscopic studies of three trabecular carcinomas of the skin. The presence of neurosecretory granules in all three tumors suggests that trabecular carcinoma originates from one of the neurocrest derivatives, most probably, Merkel cells. The ultrastructural findings confirm Toker's original concept that trabecular carcinomas comprise a distinct group of skin tumor. The recognition of these tumors would enable one to make such a diagnosis on frozen section, which, in turn, might provide an opportunity for more specific cytochemical and immunofluorescent characterization.

Reciprocal regulation of glucose and glutamine utilization by cultured human diploid fibroblasts

Abstract: Human diploid fibroblasts utilize both glucose and glutamine as energy sources. The utilization of glutamine by fibroblasts is regulated by glucose, and vice versa. This conclusion is supported by the following observations: (1) essentially identical growth rates were observed in Eagle's minimum essential medium (MEM)3 in which the glucose concentration was either 5.5 mM or was maintained between 25 and 40 micrometer, (2) the total glutamine utilization by fibroblasts increase at least 30% in medium with 25 micrometer to 70 micrometer glucose compared to medium with 5.5 mM glucose, while the rate of glutamine-1 or 5-14C oxidation to CO2 increased 5-fold as the glucose concentration was decreased to zero, (3) 2 mM glutamine inhibited glucose-6-14C oxidation by 88% and stimulated glucose-1-14C by 77% in log phase cells and (4) glutamine oxidation in normal medium contributed approximately 30% of the energy requirement of human diploid fibroblasts.

The respiratory epithelium. IV. Histogenesis of epidermoid metaplasia and carcinoma in situ in the hamster.

Abstract: The histogenesis of epidermoid metaplasia and carcinoma in situ was analyzed in human bronchial epithelium The conclusion is that epidermoid metaplasia and carcinoma in situ can result from conversion of mucous cells This implies the direct transformation of one type of fully differentiated cell to another The study therefore emphasizes the differentiation potentialities of the mucous cells that can divide and undergo goblet cell hyperplasia and epidermoid metaplasia Epidermoid metaplasia is a common reaction to injury in the bronchus In our series of cases it was especially frequent in patients without neoplastic disease who had undergone intratracheal intubation or tracheostomy and who had been maintained on a respirator in the Shock Trauma Unit, University of Maryland Future studies will be required to distinguish the difference, if any, between epidermoid metaplasia destined to become malignant carcinoma and that which is not One difference noted in this study was the absence of overt cornification in epidermoid metaplasia in patients without neoplastic disease

Diagnostic value of the Widal test in areas endemic for typhoid fever.

Abstract: The usefulness of a single Widal test to diagnose typhoid fever in endemic areas was investigated. Reciprocal Salmonella typhi O and H titers greater than or equal to 40 and greater than or equal to 80, respectively, occurred in approximately 90% of 42 Mexican patients with bacteriologically-confirmed typhoid fever at the time of presentation to hospital and, by day 4 to 5 of clinical illness, in 70% of U.S. adult volunteers who developed typhoid fever in the course of vaccine efficacy trials but in only 0.7% (O) to 3% (H) of 275 healthy individuals from a non-endemic area. Healthy Peruvians from areas endemic for typhoid fever commonly had antibody which was age-related. Peak prevalence was found in 15- to 19-yr-olds in whom 29% had O titers greater than or equal to 40 and 76% had H titers greater than or equal to 80. A single Widal test in an unvaccinated individual showing elevated O and H titers is strongly suggestive of typhoid fever if the person comes from a non-endemic area or is a child less than 10 yr of age in an endemic area. Because of the high prevalence of antibody amongst healthy invididuals over 10 yr of age in endemic, areas, a single Widal test offers virtually no diagnostic assistance in adolescents and adults.

Endoplasmic reticulum sequesters calcium in the squid giant axon.

Abstract: Axons were loaded with calcium, rapidly frozen, and freeze-substituted. The endoplasmic reticulum, in addition to mitochondria, contained calcium deposits, as indicated by electron probe x-ray microanalysis. Oxalate injected into living axons helped to preserve calcium-containing deposits during preparation for microscopy. It is concluded that the endoplasmic reticulum is a calcium-sequestering compartment in the squid giant axon.

The respiratory epithelium. I. Human bronchus.

Abstract: Six morphologic cell types comprise the human bronchial epithelium: basal cells that do not reach the bronchial lumen, neurosecretory cells (Kulchitsky's cells, K-cells, or small granule cells) that rarely reach the lumen, and indifferent cells, mucous cells [small mucous granule cells (SMGC) and mucous goblet cells], ciliated cells, and ciliated-mucous cells that do reach the lumen. Ciliated-mucous cells bearing fully developed cilia and containing mucous granules are seen only occasionally. Three of the cell types that reach the lumen are microvillus covered and do not bear cilia. The microvillus-covered nonciliated cells are: 1) neurosecretory cells, 2) indifferent cells, and 3) mucous cells. Neurosecretory cells contain characteristic dense core granules. Such cells rarely reach the lumen. Indifferent cells are rarely seen. They have a pale cytoplasm and show no evidence of either ciliary or mucous differentiation. Similar cells are observed showing early signs of either ciliary or mucous differentiation or even both types of differentiation in the same cell. Mucous cells comprise the vast majority of microvillus-covered cells. They present either as SMGC with a few small mucous granules or as goblet cells, filled with mucus. These columnar cells are characterized ultrastructurally by dense cytoplasm and a well-developed endoplasmic reticulum and Golgi apparatus. The microvilli are coated with a glycocalyx that binds colloidal iron more avidly than that of either cilia or microvilli of ciliated cells. Possible interrelationships between the different cell types in normal epithelium are discussed.

The Respiratory Epithelium. V. Histogenesis of Lung Carcinomas in the Human

Abstract: One hundred human primary lung carcinomas were studied by light and electron microscopy and by light microscopic histochemistry to demonstrate mucosubstances. The tumors were classified histogenetically and were grouped into three major categories depending on their cell of origin: 1) tumors from basal and/or mucous cells; 2) tumors from neurosecretory cells; and 3) tumors from Clara cells. Most carcinomas (88%) arose from basal and/or mucous cells. These were subdivided into epidermoid carcinomas (21%), combined epidermoid and adenocarcinomas (46%), and adenocarcinomas (21%). The criteria for epidermoid differentiation included the presence of tonofilament bundles, poorly developed endoplasmic reticulum and Golgi apparatus, and well-developed desmosomes. The criteria for adeno differentiation included well-developed endoplasmic reticulum and Golgi apparatus, poorly developed desmosomes, the presence of extracellular and/or intracellular alveoli, and/or other evidence of cellular secretion such as secretory granules. In adenocarcinomas with extracellular alveoli, typical junctional complexes were also present at the luminal aspect where the cell apexes bordered the alveolus. With these criteria, combined epidermoid and adenocarcinomas were the most common type of lung carcinoma. We anticipate that the new data will clarify categories such as small cell anaplastic carcinoma and large cell carcinoma of the World Health Organization classification. In addition, the histogenetic classification of lung tumors may be of value in the future in studies of risk factors, prognosis, prevention, and treatment of lung cancer.

Commercial ATP containing traces of vanadate alters the response of (Na+ + K+) ATPase to external potassium.

Abstract: WE have reported that the puzzling inhibition of (Na+ + K+)ATPase preparations by K+ ions, at concentrations insufficient to displace Na+ ions from the intracellular Na+-loading sites, was observed only when Sigma ‘Sigma-grade’ ATP was used as a substrate1. The effect was attributed to a contaminant of the ATP, which bound to the enzyme reversibly but with a high affinity; and because ‘Sigma-grade’ ATP is unique in being prepared from muscle, we suggested that the inhibitor might have a physiological role. Similar conclusions were reached independently by Cantley and Josephson2,3, and they and their colleagues have now identified the contaminant as ortho-vanadate4. The inhibition of (Na+ + K+)ATPase by vanadate plus K+ ions is of interest both for its possible physiological significance—traces of vanadate occur widely in animal tissues5—and for its possible use in elucidating the mechanism of the sodium pump. From both points of view it is desirable to know whether the K+ ions act at the intracellular or extracellular surface of the membrane, and we report here experiments on resealed red cell ghosts showing that the action of K+ ions is at the extracellular surface. In the following paper, Cantley et al.6 describe experiments with intact red cells suggesting that the vanadate ions act at the intracellular surface.

Prevalence, location, and patency of accessory canals in the furcation region of permanent molars.

Abstract: One hundred and two extracted permanent molars were debrided in 3% H2O2, sealed at the apex, and placed in a vacuum chamber. Safranin dye was introduced into the teeth that were placed in a vacuum of 525 mm of Hg. Observations were made of the external root surface to determine any staining due to patent accessory canals. Accessory canals were demonstrated in the "furcation region" in 28.4% of the total sample; 29.4% in mandibular molars, and 27.4% in maxillary molars. Of the total sample 25.5% exhibited canals in the "furcation" only, while 10.2% exhibited canals on the lateral root surface. Communication between the pulp chamber and the external surface was noted via dentinal tubules, especially when the cementum was denuded. The salient biologic and pathologic ramification of these aberrant canals were discussed along with the need to establish a differential diagnosis in order to determine the proper sequence of treatment should pulpal-periodontal disease exist.

Neuronal ischemic injury: Light microscopy, ultrastructure and biochemistry

Abstract: A uniform, predictable pattern of cellular abnormalities is seen after complete, irreversible ischemic injury to the central nervous system. This is in contrast to the heterogeneous, multifocal picture which characterizes incomplete ischemia. The range of abnormalities in neuronal soma after an arterial occlusion changes considerably as a function of time and site. There is no single pattern of neuronal alteration that can be ascribed exclusively to ischemia. Red neurons are a relatively late (about 18 h) indicator of ischemia and are seen only in areas where blood supply is marginal. In addition to depletion of high-energyphosphate reserves, brain ischemia results in characteristic alterations of amino acid concentrations in the ischemic tissue. Glutamate, glutamine, and aspartate either decrease or remain constant while alanine increases. Proportional decreases in the former three amino acids may be explained by simple dilution due to edema. Increases in alanine relative to glutamate and aspartate may be utilized as a biochemical index of perfusion to various brain regions.

Human pulmonary alveolar macrophages metabolise benzo(a)pyrene to proximate and ultimate mutagens

Abstract: PULMONARY alveolar macrophages (PAM) phagocytose inhaled foreign particulates that reach the peripheral airways. Particulates engulfed by PAM are then transported by the mucociliary system up the respiratory tract past the bronchial epithelium to be expectorated and/or swallowed. Since these particulates may contain adsorbed chemical carcinogens, for example, those in tobacco smoke, and PAM have been shown to metabolise chemical carcinogens1–3, PAM may interact with the bronchial epithelium in the metabolic activation of respiratory carcinogens. We report here the metabo-lic activation of benzo(a)pyrene (B(a)P) by PAM into both a promutagen ( ± )r7,t8-dihydroxy-7,8-dihydrobenzo(a)pyrene; (7,8-diol; 50% ( + )) and an ultimate mutagen(s).

Lysine metabolism in the rat brain: the pipecolic acid-forming pathway.

Abstract: — Employing both the intraventricular and intraperitoneal injection techniques, 14C-l-lysine at non-overloading concentrations was found to be metabolized to l-14C-pipecolic acid at significantly high levels in the rat. Labeled pipecolic acid in the brain and liver was only found at rather low levels 24 h after intraperitoneal administration of 14C-l-lysine regardless of non-labeled lysine metabolite overload. A marked enhancement of pipecolic acid labeling was only found in the brain when 14C-l-lysine was intraventricularly administered to animals under various lysine metabolite overloads. While overloading doses of non-labeled saccharopine or α-aminoadipate did not significantly alter the labeling patterns of pipecolic acid in the brain, liver or urine when 14C-l-lysine was intraperitoneally administered, pipecolate overloading markedly reduced labeled pipecolic acid levels in the brain, liver and urine. These results indicate: pipecolic acid formation is subject to product inhibition, and saccharopine is not in the pathway of pipecolic acid synthesis from l-lysine. The labeling pattern of lysine metabolites was not significantly affected by the overloading injection of pipecolic acid when 14C-l-lysine was intraventricularly administered suggesting a blood-brain barrier for pipecolate. Besides 14C-pipecolic acid, labeled α-aminoadipic acid was also found at significant levels mostly in the brain. Labeled saccharopine was not detected in any tissues or urine samples analyzed. The 14C-l-lysine metabolic pattern of the newborn rats did not seem to be any different from the adult rats, i.e. labeled pipecolic acid was also detected in substantial quantities in the brain, liver and urine 5 h after injection. 14C-d-Lysine was mainly metabolized to l-14C-pipecolic acid through either route of administration. These experimental evidences indicate that the pipecolic acid-forming pathway is a significant route for lysine metabolism in the rat, and that the rat brain probably utilizes this pathway mainly for lysine metabolism. The present study also discusses the potential neurological significance of the pipecolic acid pathway in relation to the major lysine metabolic pathway (the saccharopine pathway).

Studies on the pathogenesis of ischemic cell injury

Abstract: In summary, we have described the time course of changes of mitochondria following ischemia of the kidney proximal tubule. The sequence of morphological changes of matrix as well as inner membrane corresponds well with certain functional or physical parameters such as swelling, respiration, substrate metabolism, acceptor control and P/O ratio. This indicates that morphological parameters can be utilized to predict the functional alterations of mitochondria following ischemia in cells. The significant mitochondrial changes are early loss of granules (15–30 min) and condensation (15 min), swelling (30 min), appearance of fluffy densities (30 min) and flocculent densities (after 60 min), degeneration of cristal structure (240 min) and disintegration of mitochondria as structural units (24 h).

The Respiratory Epithelium. II. Hamster Trachea, Bronchus, and Bronchioles

Abstract: The normal female hamster respiratory epithelium at five airway levels was characterized with the use of coordinated morphologic and histochemical techniques. Five morphologic cell types were recognized in the trachea, stem bronchi, and primary bronchl: basal cells and neurosecretory cells that were basally located and did not reach the lumen and mucous cells [mucous goblet cells and small mucous granule cells (SMGC)], indifferent cells showing mucous-ciliary differentiation, and ciliated cells that reached the lumen. Two epithelial cell types were observed in the bronchioles, ciliated cells and nonciliated Clara cells, both of which reached the lumen. Mucous cells presented as either SMGC with a few small periodic acid-Schiff-positive granules (diastase-resistant neutral mucosubstances) or as goblet cells, filled with the same material. Mucous cells were columnar, and the cytoplasm was electron-dense and contained a well-developed endoplasmic reticulum and Golgi complex. The microvilli of the mucous cells were coated more thickly with colloidal iron than either the cilia or microvilli of ciliated cells. Approximately one-half the cells in the trachea, bronchi, and bronchioles were ciliated. Ciliated cells containing intracellular ciliated cysts with normal cilia projecting into a closed space or ciliated cells bearing compound cilia were observed infrequently. Neurosecretory cells were rarely observed. These cells contained characteristic dense-core granules.

Inhibitor of Oocyte Maturation from Porcine Follicular Fluid: Further Purification and Evidence for Reversible Action

Abstract: The. its vitro culture of porcine oocytes was used as a bioassay for inhibitory fractions from PM-b membrane filtration. Sephadex G-25 column chromatography and paper electrophoresis of porcine follicular fluid (FF1). A 100-fold purification ofthe inhibitor of oocyte meiosis from the PM-I Oconcensratc was achieved. The major inhibitory fraction had a molecular weight of less than 2,000. Freshly collected. unfractionased FF1 also contained inhibitory activity, with significant inhibition exhibited by fluids from small and medium sized follicles. The inhibition of maturation by unfractionased FF1. the PM-b filtrate and the inhibitory peak from the Sephadex column could be reversed when the inhibitory fraction was removed from oocyte cultures by 20-24 h after the initiation of culture. The modifications from previously reported purifications of the inhibitor from FF1 and the finding of a reversible arrest of porcine oocyte maturation are discussed.

Experimental gram-negative bacterial sepsis: reevaluation of the ability of rough mutant antisera to protect mice.

Abstract: SummaryRabbit antisera to three rough Enterobacteriaceae mutants, the Rc chemotype of Escherichia coli J5, the Rd chemotype of Salmonella typhimurium SL 1032, and the Re chemotype of Salmonella minnesota 595, were administered iv or ip to outbred Swiss albino mice. Control animals were injected concomitantly with normal serum from the same donors obtained prior to immunization. One hour later, challenge was performed ip or iv with LD95-100 doses of viable Escherichia coli 018, Proteus mirabilis, or Klebsiella pneumoniae. Normal pre-immune rabbit sera, lacking detectable antibodies to the specific challenge bacterial strains or to Ra, Rc, Rd, or Re rough mutants of Enterobacteriaceae, exhibited definite abilities to reduce septic mortality when compared with physiologic sterile saline. Analysis of preimmune sera from individual rabbit donors revealed a wide spectrum of protective activity. Post-immune sera against the rough bacterial mutants, possessing high titers of Rc, Rd, or Re antibodies, conferred no...

An experimental analysis of interlamellar tight junctions in amphibian and mammalian C.N.S. myelin.

Abstract: The distribution of interlamellar tight junctions was examined in myelin sheaths ofXenopus tadpole optic nerve and rabbit epiretinal tissue fixed with aldehydes, postfixed with osmium ferrocyanide and embedded in a water-soluble medium, Durcupan. Intramyelinic zonulae occludentes were clearly formed by fusion of adjacent intraperipd lines which corresponded to the external leaflets of oligodendrocytes. These occurred in register with other tight junctions present within successive lamellae and appeared as a series of radial lines extending either partially or totally across the thickness of the myelin sheath. This distribution of zonulae occludentes corresponded with that of tight junctional particle strands observed in freeze-fracture replicas. Analysis of intramyelinic vacuolation induced by hexachlorophene (HCP) intoxication indicated that lamellar splitting was frequently limited by the tight junctions. The intramyelinic zonulae occludentes also restricted the diffusion of colloidal lanthanum which had penetrated the myelin intraperiod gap followingin vivo perineural injection. The results of this study provide evidence favouring a correspondence between interlamellar tight junctions and the ‘radial component’ of myelin described earlier by other investigators. Furthermore, observations of swollen myelin sheaths, resulting from HCP intoxication, suggest that these junctions may play a major role in maintaining myelin sheath integrity and limiting the extent of breakdown during certain pathological conditions.

Kinetic analysis of end plate currents altered by atropine and scopolamine.

Abstract: The decay phase of end plate currents in voltage-clamped frog sartorius muscle follows a single exponential function whose rate varies with membrane potential. Atropine increased the end plate current decay rate and reduced its voltage sensitivity, but did not alter its exponential nature. Scopolamine transformed the end plate current decay into a biphasic waveform consisting of a rapid initial current, followed by a slow terminal current. Two kinetic models were examined for their ability to simulate these drug-induced alterations of the end plate current. The models were formulated on the assumption that the drug molecules bind to the activated transmitter-receptor complex and induce sequential conversion of the end plate channel from a transient state of high conductance to a prolonged state of low or zero conductance. Drug binding was irreversible according to model I, and the complex of drug with the end plate channel was partially conducting. In model II the binding step was made reversible, and the resulting drug-channel complex was considered to be nonconducting. The predictions from these kinetic models were compared with data from voltage-clamped end plates. The theoretical end plate currents from model II agreed closely with experimental values, while those from model I were in conflict with the data. ACKNOWLEDGMENTS The authors thank Ms. Mabel Alice Zelle for technical assistance, and Mrs. Margaret Shimkaveg for help in preparation of the manuscript.

Lysine metabolism in the rat brain: blood—brain barrier transport, formation of pipecolic acid and human hyperpipecolatemia

Abstract: — Through the use of intravenous pulse injection of L-[U-14C] lysine, the blood-brain barrier transport of L-lysine was studied. The uptake of L-lysine plus metabolites in the brain remained essentially unchanged at approx 0.002–0.005 nmol/g in the low dose (3μg per kg body weight) injection, and 20–40 nmol/g in the high dose (30 mg/kg) injection throughout the time intervals of up to 60 min. The uptake of L-lysine plus metabolites in the heart, however, decreased substantially from 0.03 to 0.003 nmol/g in the low dose injection and from 320 to 62 nmol/g in the high dose injection. The plasma to heart uptake ratio only decreased slightly through the 60 min period: from 6 to 2 in either the low or high dose L-lysine injection. The plasma to brain uptake ratio, however, decreased rapidly from a high of 62 to a low of about 4 in either the low or high dose injection throughout the 60-min time course. Study of labeled L-pipecolate formation in the plasma and individual organs indicates that this compound was formed only in the brain to a significant level within 0.5 min of 14C-L-lysine intravenous pulse injection. Labeled pipecolate was recovered from heart, liver, kidney and plasma in significant quantities only at 2 min or later after pulse-injection. It is concluded that the blood-brain barrier of L-lysine in the rat is not particularly strong and that the rat brain may be primarily responsible for L-pipecolate synthesis from L-lysine. The possible etiology of human hyperpipecolatemia is also discussed in light of the current findings.