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Biomedical subjects

J H Johnson

Publications and source records attributed to J H Johnson.

At least 127 records · Page 7Linked to original sources
PubMed1985

An autoradiographic study of rabbit ovarian surface epithelium before and after ovulation.

Morphologic studies suggest that the proliferative activity of the ovarian surface epithelium (OSE) may vary during the reproductive life cycle. To further investigate this phenomenon, rabbit ovaries obtained before and after induction of ovulation with human chorionic gonadotropin (hCG) were incubated in medium containing 3H-methylthymidine and processed for autoradiography. Before ovulation, the labeling index (LI) of OSE cells varied from 0.04% to 0.22%. Twelve hours after hCG, the maximal LI (9.02 +/- 0.38%) was seen in OSE cells adjacent to the ovulatory stigma. The LI remained elevated at Days 1 and 5 post-hCG in OSE cells overlying corpora lutea. At Day 12, numerous papillary processes were observed at the apex of each corpus luteum. The maximal LI (16.44 +/- 1.31%) had now shifted to the OSE cells covering these processes. Eighteen days after hCG stimulation, the LI of OSE cells near the corpora lutea had returned to preovulatory levels. A slight increase in the LI of OSE cells not associated with ovulatory sites was also observed after ovulation. This study shows that a significant fraction of OSE cells undergoes DNA synthesis throughout most of the postovulatory period.

Animals↗
PubMed1985

The harmful effects of ethanol on ion transport and cellular respiration.

The deleterious effects of ethanol on a variety of tissues may result largely from altered ion permeabilities and transport. Clinically relevant ethanol concentrations in blood increase the sodium permeability of the plasma membrane and depress active sodium transport by suppressing Na, K-ATPase activity. As a result, intracellular sodium concentration increases. The total tissue content of calcium increases. Important transport mechanisms deranged by ethanol probably include those regulating calcium-sodium and hydrogen-sodium exchange at the plasma membrane and calcium uptake by the sarcoplasmic reticulum. A modest decline in magnesium content of muscle occurs after chronic exposure to ethanol. This also has been associated with accumulation of calcium. After days to weeks of sustained ethanol intake, sodium pump activity, active sodium transport and tissue oxygen consumption increase. The cell membrane potential, initially lowered by alcohol, increases to supraphysiological levels. This is likely an electrogenic effect of increased sodium transport in response to a sodium leak. Eventually the earlier derangements in tissue composition, including retention of sodium, chloride, and calcium, and reductions in magnesium, potassium, and phosphate, slowly undergo correction. This biphasic response of injury and adaptation appears to depend upon adequate nutrition and the absence of other factors that can adversely affect cell function. That the Na, K-ATPase activity and oxygen consumption remain elevated suggests an ongoing sodium leak of the sarcolemmal membrane. Chronic ethanol-induced cell necrosis may be related to the increased intracellular calcium that accompanies the increase in sodium permeability. Conceivably, critically elevated concentrations of calcium in the cytoplasm may activate autolytic enzymes that in turn may be responsible for structural damage to the cell.

Animals↗
PubMed1985

Growth characteristics of rabbit ovarian mesothelial (surface epithelial) cells.

This study analyzes the morphology and growth characteristics of rabbit ovarian mesothelial (surface epithelial) cells explanted in vitro. Best cell growth and expression of differentiation were obtained using a polystyrene substrate, 100% air, and a nutrient composed of 85% medium 199 and 15% fetal bovine serum. Surface epithelia gave rise to cell outgrowths within 36 h of explantation and formed confluent epithelial monolayers after 1 week. Cells exhibited a marked proliferative activity as indicated by: (a) a labeling index of 80% at day 4, and of 40% at days 10 and 38; (b) a cell doubling time of 30-36 h during the logarithmic phase of growth; and (c) an estimated 24 cell population doublings during 6 weeks. Confluent cultures contained cells complexed by desmosomes and tight junctions and displaying numerous microvilli, intracellular lumina, and focal cilia. Cells organized often into nests and gland-like spaces and developed occasional hemicysts. High-density cultures developed also a multilayered configuration, villous processes, epithelial invaginations or crypts, and focal cytological features suggestive of steroidogenesis. This study shows that rabbit ovarian surface epithelial cells can be maintained in vitro with a high degree of differentiation. This model is being used to investigate the pathobiology of ovarian surface epithelium.

Animals↗
PubMed1985

Muscle cell electrical hyperpolarization and reduced exercise hyperkalemia in physically conditioned dogs.

Contracting muscle cells release K ions into their surrounding interstitial fluid, and some of these ions, in turn, enter venous plasma. Thereby, intense or exhaustive exercise may result in hyperkalemia and potentially dangerous cardiotoxicity. Training not only reduces hyperkalemia produced by exercise but in addition, highly conditioned, long-distance runners may show resting hypokalemia that is not caused by K deficiency. To examine the factors underlying these changes, dogs were studied before and after 6 wk of training induced by running on the treadmill. Resting serum [K] fell from 4.2 +/- 0.2 to 3.9 +/- 0.3 meq/liter (P less than 0.001), muscle intracellular [K] rose from 139 +/- 7 to 148 +/- 14 meq/liter (P less than 0.001), and directly measured muscle cell membrane potential (Em) in vivo rose from -92 +/- 5 to -103 +/- 5 mV (P less than 0.001). Before training, resting Em of isolated intercostal muscle in vitro was -87 +/- 5 mV, and after incubation in 10(-4) M ouabain, Em fell to -78 +/- 5 mV. After training, resting Em of intercostal muscle rose to -95 +/- 4, but fell to -62 +/- 4 mV during incubation in 10(-4) M ouabain. The measured value for the Em was not completely explained by the increased ratio of intracellular to extracellular [K] or by the potassium diffusion potential. Skeletal muscle sarcolemmal Na,K-ATPase activity (microM inorganic phosphate mg-1 protein h-1) increased from 0.189 +/- 0.028 to 0.500 +/- 0.076 (P less than 0.05) after training, whereas activities of Mg2+ -dependent ATPase and 5'nucleotidase did not change. In untrained dogs, exercise to the point of exhaustion elevated serum [K] from 4.4 +/- 0.5 to 6.0 +/- 1.0 meq/liter (P less than 0.05). In trained dogs, exhaustive exercise was associated with elevation of serum [K] from 3.8 +/- 0.3 to 4.2 +/- 0.4 (NS). The different response of serum [K] to exercise after training was not explainable by blood pH. Basal insulin levels rose from 7.0 +/- 0.7 microU/ml in the untrained dogs to 9.9 +/- 1.0 microU/ml (P less than 0.05) after training. Although insulin might have played a role in the acquired electrical hyperpolarization, the reduced exercise-produced hyperkalemia after training was not reversed by blockade of insulin release with somatostatin. Although the fundamental mechanisms underlying the cellular hyperpolarization were not resolved, our observations suggest that increased Na-K exchange across the sarcolemmal membrane, the increase of Na,K-ATPase activity and possibly increased electrogenicity of the sodium pump may all play a role in the changes induced by training.

Animals↗
PubMed1985

Catacandins, novel anticandidal antibiotics of bacterial origin.

Two novel antibiotics, catacandin A and catacandin B, were isolated from the fermentation broth of the bacterium, Lysobacter gummosus, by extraction and adsorption, reverse-phase and gel filtration chromatography. On the basis of their physico-chemical properties, they are acyltetramic acids that are easily distinguishable from others in this class. Catacandin A and catacandin B possess good anticandidal activity.

Anti-Bacterial Agents↗
PubMed1985

Two new inhibitors of phospholipase A2 produced by Penicillium chermesinum. Taxonomy, fermentation, isolation, structure determination and biological properties.

Plastatin and the known fungal metabolite, luteosporin, have been isolated from fermentations of Penicillium chermesinum as inhibitors of porcine pancreatic phospholipase A2 (PLA2). Structure 1 for plastatin was deduced from its spectroscopic properties. Plastatin and luteosporin inhibited pancreatic PLA2 competitively with Ki values of 0.89 microM and 12.8 microM, respectively. PLA2 preparations from Naja naja and Crotalus adamanteus were not significantly inhibited by plastatin and luteosporin.

Chemical Phenomena↗
PubMed1985

A followup study of ibuprofen users.

We followed up 13,230 members of the Group Health Cooperative of Puget Sound under the age of 65 years who were presumed to have taken ibuprofen as out patients. All hospitalizations that occurred within 3 months after a prescription for ibuprofen was filled were reviewed. We found no instances of serious uncommon illness which could be attributed to this drug with any reasonable degree of certainty. In particular, there were no cases of acute liver or kidney disease noted within 3 months of exposure to ibuprofen.

Adult↗
PubMed1984

Replicated item level factor analysis of the full MMPI.

We completed a comprehensive factor analysis of the full MMPI item pool by using recent advances in computational facilities. Nearly 20,000 MMPI protocols were collected for the analysis, however, we discarded invalid records and protocols with more than 50 missing items. Analyses were computed on a developmental sample of 5,506 subjects and a cross-validation sample of 5,632. Twenty-one replicated factors were found by using an orthogonal varimax solution. The rotated factors were submitted to several experts on MMPI for factor naming. The consensus obtained on the item factors suggests that this analysis provides an unambiguous picture of the major content dimensions in the MMPI item pool.

Adolescent↗
PubMed1984

Surface morphology of ovarian mesothelium (surface epithelium) and of other pelvic and extrapelvic mesothelial sites in the rabbit.

The morphology of the ovarian mesothelium (surface epithelium) and of other pelvic and extrapelvic mesothelia was investigated in the rabbit by use of scanning electron microscopy. Villous processes of varied architectural complexity and surface epithelial crypts were found in the ovary but not in the mesothelial linings of the oviduct, uterus, liver, or pelvic and abdominal walls. Both ovarian and extraovarian mesothelial cells possessed abundant microvilli. Fully developed individual cilia and ciliary tufts were seen exclusively in ovarian mesothelia, while abortive or blunted cilia were rarely seen in pelvic but not in extrapelvic mesothelia. A distinct transition in surface configuration was present in contiguous mesothelia. In fact, ovarian mesothelia containing numerous villous processes, crypts, and cuboidal to low columnar cells merged with oviduct and fat mesothelia displaying only flat or low cuboidal cells. Villous processes were often lined by a stratified or pseudostratified epithelium and this histology resembled that of ovarian surface papillomas. Processes were more numerous in smaller ovaries than in larger ovaries where interstitial tissue and corpora lutea were prominent. This study underscores the unique architecture and morphogenetic behavior of the ovarian mesothelium. It also suggests that local factors and/or reproductive patterns may have a role in regulating the growth and development of this important ovarian component.

Animals↗
PubMed1984

Muraceins--muramyl peptides produced by Nocardia orientalis as angiotensin-converting enzyme inhibitors. II. Isolation and structure determination.

Three new muramyl peptides ( muraceins A, B and C) have been isolated from fermentations of Nocardia orientalis as inhibitors of angiotensin-converting enzyme (ACE). Structures 1 and 2, for muraceins A and B respectively, were deduced from their spectroscopic properties. Muracein C, 3, was shown to be a muramyl pentapeptide containing N-acetylmuramic acid, alanine, glutamic acid, serine and diaminopimelic acid in a 1:2:1:1:1 ratio based on the 1H NMR integration.

Acetylmuramyl-Alanyl-Isoglutamine↗
PubMed1984

Effects of two international union against cancer standard reference samples of asbestos on cultured rabbit ovarian surface epithelial cells.

To evaluate their interaction with asbestos, rabbit ovarian surface epithelial cells were exposed in vitro to amosite or Rhodesian chrysotile fibers (5.0 micrograms/ml). The morphology of these cells was studied by phase-contrast, scanning and transmission electron microscopy. Amosite fibers up to 10 micron in length were phagocytized by surface cells within 24 hours. Internalization of amosite fibers occurred prevalently over microvilli-rich regions of the cell surface and, after 4 days, the intracytoplasmic localization of these fibers was most often perinuclear. In contrast with amosite, chrysotile fibers were less frequently phagocytized. Instead, they caused focal cell membrane damage, intracytoplasmic vacuolization and cell clumping. A different effect of the two asbestos fibers was also observed when estimates of cell growth were obtained in replicate cultures exposed to fibers before cell confluence. In contrast with asbestos-free cultures which underwent a 4.3 fold increase in cell number, cells exposed to amosite displayed nearly a 7-fold numerical increase (ca. 160% of controls; P less than 0.05). Cells maintained in presence of chrysotile grew 3.5 fold (approximately 80% of controls). When administered at the time of cell plating, both mineral fibers (chrysotile greater than amosite) significantly depressed cell growth. These data indicate that amosite and chrysotile asbestos can have cytotoxic or proliferative effects on ovarian surface epithelial cells. Further investigation is required to ascertain if susceptibility of these cells to mineral fiber injury may play a role in the genesis of proliferative ovarian surface lesions.

Animals↗
PubMed1984

Isolation and ultrastructure of rabbit ovarian mesothelium (surface epithelium).

This study evaluated the efficacy of various dissociating procedures for isolating mesothelial or surface epithelial cells from rabbit ovaries. The procedure which provided the highest and most homogenous cell yield involved the following sequence: (a) incubation of whole ovaries for 60 min in Clostridium histolyticum collagenase, type I (300 U/ml); (b) vortexing of ovaries at 30 rpm for 60 s in medium 199; (c) removal of partially detached surface epithelium by gentle scraping with a microdissecting blade; and (d) unit gravity enrichment of isolated epithelial organoids (surface layers and villous processes). As shown by light and ultrastructural microscopy, this procedure cleaved the surface epithelium from over two-thirds of the underlying basement membrane and tunica albuginea. As estimated by further dispersal of epithelial organoids with trypsin-EDTA, 0.8 to 1.5 X 10(6) surface cells were routinely obtained from a single ovary. This isolation procedure is simple and provides an experimental tool for investigating in vitro the regulation and developmental behavior of ovarian surface epithelium.

Animals↗
PubMed1984

Morphology of rabbit endocervical mucosa after mating.

The distribution and morphology of rabbit endocervical mucous cells before and after mating were studied histochemically with Alcian blue, pH 2.5, and periodic acid-Schiff (AB-PAS) and by scanning and transmission electron microscopy. Before mating, the lower and upper segments of the endocervical canal contained approximately 75% and 93% of cells engorged with AB-PAS positive granules. Two hours after mating, the percentage of histochemically positive cells decreased to less than 46% and 85%, respectively. Before insemination, mucous cells were prominent among ciliated cells and contained numerous secretory granules some of which appeared to be undergoing release through exocytosis. Granule-engorged apices of mucous cells were rarely seen after insemination. Instead, cells displayed a markedly reduced complement of mucous granules and their apical surface contained numerous exocytotic pits. In many areas, a blanket of mucous material covered mucous and ciliated cells. As for the observed variation in mucous cell distribution, these changes were predominant in the endocervical mucosa of the lower cervix. We have previously shown that both native and isolated mucous cells respond to serum with rapid and massive granule release. Degranulation of endocervical mucous cells in response to semen may play an important role in regulating sperm access to the upper reproductive tract under physiologic and pathologic conditions.

Animals↗
PubMed1983

The role of ATPase in glycolysis of Ehrlich ascites tumor cells.

Glycolysis in Ehrlich ascites tumor cells suspended in buffer containing 5 mM Pi was 50% inhibited by ouabain. In the absence of Pi the inhibition was less striking. Permeabilization of the cells with filipin abolished glycolysis, but glycolysis was restored by addition of Pi and AMP. Neither ouabain nor quercetin inhibited glycolysis in these permeabilized cells. We conclude that quercetin did not inhibit hexokinase sufficiently to affect glycolysis. An extract of Ehrlich ascites tumor cells glycolyzed weakly unless either Pi or an ATPase (e.g. (Na+K+)-ATPase) was added. The low rate of glycolysis of the extract was even further reduced when an endogenous ATPase was removed by precipitation with CaATP. The glycolytic activity of this ATPase-deficient extract was restored by addition of purified (Na+K+)-ATPase or of CaATP-precipitable ATPase. Addition of hexokinase without Pi did not restore glycolytic activity to the extract. An explanation for the contradictory conclusions by Bustamante, E., Morris, H.P., and Pedersen, P.L. (J. Biol. Chem. (1981) 265, 8699-8704) is presented.

Adenosine Triphosphatases↗
PubMed1983

Validity of a computerized on-line MMPI interpretive system.

Three independent, experienced clinicians trained at the University of Minnesota were asked to rate the quality and accuracy of codetype interpretations and associated rules used in the Psych Systems' automated MMPI program. Results showed that this system is rated highly by clinicians. The authors discuss how this approach can be used in validating other automated test interpretation systems and suggest that feedback by expert judges can be used to improve such systems.

Computers↗
PubMed1983

MMPI clinical and content norms for a mixed psychiatric adolescent population.

Presented a set of MMPI norms for a mixed psychiatric group of adolescents (N = 1022). Normative information is stratified according to five age categories and includes means and standard deviations for the validity, clinical, and 48 content scales. The usefulness of these norms for clinicians is discussed.

Adolescent↗