Insulin-like growth factor 1 receptors are increased in estrogen-induced kidney tumors

We have previously demonstrated that membrane receptor protein tyrosine kinase(s) activities are higher in estrogen-induced kidney tumors in comparison with such activities in the normal kidney. In the present work we have investigated the growth factor binding sites in estrogen-induced kidney tumor and in normal kidney membranes in an attempt to understand the mechanism of activation of membrane protein tyrosine kinase(s) and their possible relationship to the induction of estrogen-induced tumors. The characteristics of the normal hamster kidney membrane insulin-like growth factor 1 (IGF-1) receptor are similar to those reported for kidney and extrarenal tissues of other rodents. The binding of 125I-IGF-1 to the normal kidney or tumor membranes was saturable and dependent on time, protein, pH, and temperature. The binding of 125I-IGF-1 to the tumor membranes was significantly higher when compared to the binding activity of the membranes obtained from age-matched normal kidney. The Scatchard analysis of the binding data of both tumor and normal kidney revealed a single class binding site for IGF-1 with Kd of 1.7 and 1.8 nM and maximum binding capacities of 4150 and 2050 fmol/mg protein, respectively. Therefore, the difference observed in 125I-IGF-1 binding between tumor and normal kidney membranes was due to an increase in the number of IGF-1 binding sites with no change in the affinity of receptors for IGF-1. An enhanced level of IGF-1 receptors in tumor membranes also was visualized by autoradiography following affinity labeling of membrane proteins subjected to sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Under reducing conditions of electrophoresis, two molecular bands of M(r) 240,000 and M(r) 130,000 were evident. The M(r) 130,000 band represents the alpha subunit of IGF-1 receptors, and the M(r) 240,000 band may represent the aggregates of the receptor subunits which were not reduced completely. IGF-1 stimulated normal kidney or tumor membrane protein tyrosine kinase(s) (wheat germ lectin agarose-purified membrane proteins) in a dose-dependent fashion. Therefore, the alteration of IGF-1 binding activity of the tumor membrane receptors and stimulation of IGF-1-mediated membrane protein tyrosine kinase activity in tumor tissues suggest that events coupled to this membrane receptor may play a role in estrogen stimulation of renal carcinoma.

Detection of [U-13C]eicosapentaenoic acid in rat liver lipids using 13C nuclear magnetic resonance spectroscopy

Fatty acid carbons are well-resolved in 13C nuclear magnetic resonance (NMR) spectra of lipid extracts, but application of this methodology to the metabolism of 13C-labelled fatty acids has not yet been reported. In the present study, 13C NMR was used to monitor the presence of 98% [U-13C]eicosapentaenoic acid (EPA) in liver and carcass lipids 24 h after it had been injected into the stomach of a rat. Natural abundance 13C NMR spectra of liver total fatty acid extracts were obtained from four control rats for comparison. At 24 h post-injection, quantitative high resolution 13C NMR showed 13C enrichment in liver fatty acid extracts was present mainly at olefinic and at the n-1 to n-4 carbons, but 13C signal intensities for C-1 to C-4 of [U-13C]EPA were markedly reduced or absent. Small 13C resonances, possibly indicative of some 13C incorporation into docosahexaenoic acid and saturated or monounsaturated fatty acids, were present in spectra of liver fatty acids. Liver and carcass fatty acid composition was similar in both the controls and the EPA-injected rat, suggesting little accumulation of the injected [U-13C]EPA after 24 h. We conclude that the carbon-specific data provided by 13C NMR of lipid extracts may be useful in monitoring the fate of individual carbons during tracer studies using 13C-labelled fatty acids.

Animated visualization of a high resolution color three dimensional digital computer model of the whole human head

The interactive visualization of animated images through a computerized three dimensional (3D) full color model of an unstained cadaveric human head is presented. Serial full color images were taken of the blockface of a cryomicrotomed frozen human head every 200 microns. From this series of images a three dimensional digital model with a resultant pixel resolution of 200 microns3 was created on a UNIX workstation. Using this database, resampled images were computed along orthogonal axes and written sequentially to a write-once-read-many times (WORM) videodisc unit. Playback of this customized videodisc dataset provides animations of the digitally reconstructed slices and 3D reconstructed surface models. An interactive interface to the animated sequences is provided through a PC based tutorial package. This tutorial program is able to access videodisc frames to display animations and labeled still images in a software window to illustrate various neuroanatomic topics. The technique of animation as applied to this high resolution 3D model provides insight into complex spatial relationships and has great potential in research and as a teaching tool in the neurosciences.

Estradiol is trophic for colon cancer in mice: effect on ornithine decarboxylase and c-myc messenger RNA

The mitogenic role of estradiol on the growth of colon cancer was examined in mice. Sham-operated or ovariectomized mice were injected with cancer cells and received estradiol treatment. Tumor growth was noted: tumor weights were higher in female than male mice. The growth of the tumors was least in ovariectomized mice and highest in estradiol-treated ovariectomized mice. Tumor messenger RNA (mRNA) levels for ornithine decarboxylase (ODC) and proto-oncogenes c-myc, c-fos, and H-ras were examined. Two transcripts (2.2 and 2.7 kilobase pairs) of ODC were observed. The steady-state mRNA levels for ODC paralleled the changes observed in the weight of the tumors in all groups of animals. Less dramatic changes were observed in c-myc mRNA levels. No significant differences were observed in the mRNA levels for H-ras and c-fos. It thus appears likely that an increase in the ODC mRNA levels and, to a lesser extent, an increase in c-myc mRNA levels may be some of the important mechanisms by which estradiol mediates its growth effects on colon cancer cells in vivo.

Enhanced expression of membrane phosphoproteins tyrosine phosphorylation in estrogen-induced kidney tumors

We demonstrate for the first time that the expression of tyrosine containing membrane phosphoproteins is elevated in estrogen-induced kidney tumors, which is evident from both the types of experiments, i.e., alkali-resistant phosphorylation of membrane proteins and immunoprecipitation of tyrosine containing phosphoproteins. Tyrosine phosphorylation of proteins or peptides was modulated by the growth factors (EGF, IGF-I) and by the inhibitors of tyrosine protein kinase(s). The kinetic analyses revealed that tumor membranes have high affinity and catalytically more efficient tyrosine phosphorylating kinase enzyme(s) compared to that of normal membranes which have low affinity and catalytically less efficient kinase enzyme(s). It is proposed that overexpression of tyrosine containing membranal phosphoproteins may be involved in the induction and growth of estrogen-induced renal neoplasm.

Hemostatic profile in septicemic neonates with and without bleeding

Hemostatic profile was studied in 25 full term, non-asphyxiated neonates with blood culture-proven septicemia. Nine (36%) of these neonates manifested bleeding. Detailed coagulation tests and platelet studies were deranged in 24 (96%) of neonates with septicemia. Abnormalities in coagulation tests did not differ in those with and without bleeding. Only platelet aggregation with ADP was deranged to a significantly greater extent in those with bleeding as compared with those without bleeding.

Characterization of gastrin binding to colonic mucosal membranes of guinea pigs

Gastrin has significant growth and metabolic effects on colonic mucosal cells. It is, however, not known if gastrin receptors are present on colonic mucosal cells that may directly mediate the reported biological effects of gastrin. In the present studies, the presence of specific gastrin binding sites on colonic mucosal membranes was investigated and the binding sites were further characterized. Crude membranes from colonic mucosa of guinea pigs were analyzed for specific binding to gastrin by our published procedures. A significant number (14.7 +/- 1.8 fmoles/mg protein) of high affinity gastrin binding sites (Kd = 0.49 +/- 0.05 mM) were measured, that were specific for binding gastrin/CCK related peptides and demonstrated negligible binding affinity for all other unrelated peptides examined. In addition a large number of low-affinity (Kd = approximately 1 microM) binding sites were present. In order to further characterize the molecular size of gastrin binding proteins, we used the chemical cross-linking methods, and observed at least four bands of gastrin binding proteins (GBPs) (approximately 33, 45, 80 and 250 KDa), both under reducing and non-reducing conditions, indicating that these proteins were not sub-units of forms linked by disulfide bonds. Interestingly, majority of the specific gastrin binding sites (approximately 70%) were present on the 45 KDa protein, unlike other target cells of gastrin. The presence of N- and O-linked glycosylated moieties were indicated on the 45 KDa protein, based on enzymatic de-glycosylation studies.(ABSTRACT TRUNCATED AT 250 WORDS)

Characterization of insulinlike growth factor I receptors in human colon cancer

A possible role of insulinlike growth factor I (IGF-I) and IGF-I receptors in the proliferation of human colon cancer has, to the best of the authors' knowledge, not been examined as yet. To determine a role of IGF-I in colon cancer, several human colon cancer cell lines and colon cancers were screened for specific binding to 125I-IGF-I. Almost all the human colon cancer cells examined were variably positive for specifically binding 125I-IGF-I. Almost half the colon cancer cell lines examined showed significant growth response to 6.6 nmol/L IGF-I. Dose-dependent growth effects of exogenously added IGF-I (0.05-3.3 nmol/L) were shown in a representative human colon cancer cell line (Colo-205). To determine if IGF-I binding sites on colon cancer cells were similar or different from that described on other cells, the binding affinity, binding specificity, and molecular size of the IGF-I binding sites were characterized in representative human colon cancer cell lines (HCT-116 and Colo-205). The optimal binding assay conditions for measuring maximum number of 125I-IGF-I binding sites on the cells, in vitro, were determined and found to be similar to that described on other cells. Scatchard analysis of the specific binding data showed the presence of a single class of high-affinity binding sites [disassociation constant (Kd) = approximately 1.0-2.0 nmol/L], with a binding capacity of 1.0-2.0 x 10(5) sites per cell. The molecular weight of IGF-I receptors on cell membranes was determined by gel electrophoresis of the affinity cross-linked proteins, followed by autoradiography. A single band of binding proteins with a molecular mass of approximately 300 kilodaltons was evident under nonreducing conditions and separated out into two bands of approximately 240 and approximately 130 kilodaltons under reducing conditions. The 130-kilodalton band represents the alpha subunit of IGF-I receptors, and the 240-kilodalton band may represent aggregates of the receptor subunits that were not reduced completely. The widespread existence of high-affinity binding sites for IGF-I in established human colon cancer cell lines and freshly resected human colon cancers and the proliferative effect of IGF-I in several colon cancer cell lines, in vitro, reflect that IGF-I may be an important endocrine/paracrine/autocrine factor in the growth regulation of colon cancers in situ.

Acute leukaemic cell infiltration of the nose

Leukaemic cell infiltration of the nose as a first manifestation of the disease is extremely rare. We report a case of a three-year-old child who had presented with a swelling at the root of the nose for one month and proptosis of the right eye for one week. CT scan revealed a mass infiltrating the nose and nasal cavity along with infiltration of the retro-orbital region. Biopsy showed it to be myeloid cell deposits. Patient was put on antileukaemic chemotherapy but died two months after the first appearance of the symptoms.

Hemostatic profile in neonatal septicemia

Hemostatic profile was studied in 25 full term non-asphyxiated neonates with blood culture-proven septicemia. Observations were compared with that of 25 healthy, non-asphyxiated, full term, birth weight and age-matched controls. Detailed coagulation tests & platelet studies were done in each of the 50 neonates by standard techniques. Hemostatic defects occurred in 96% of the septicemic neonates and none in the control group irrespective of the occurrence of clinical bleeding. The coagulation tests were deranged in 805 and platelet function tests in 92% of patients. These tests were significantly deranged in septicemic neonates as compared to control group.

A potent bombesin receptor antagonist inhibits bombesin-stimulated growth of mouse colon cancer cells in vitro: absence of autocrine effects

Bombesin (BBS) exerts significant effects on the growth of a mouse colon cancer cell line (MC-26) in vitro. The presence of specific binding sites on MC-26 cells for gastrin-releasing peptide (GRP)/BBS-related peptides was recently reported by us. In the present study, we determined that the transcript size of the mRNA species that codes for GRP receptors is 9 kilobase pairs, which is similar to that reported for mouse Swiss 3T3 cells, using the complementary DNA probe for the GRP receptor gene from mouse Swiss 3T3 cells. We next examined the effects of potent GRP receptor antagonists, D-Phe6, bombesin(6-13)-propylamide (D-Phe6,BN(6-13)PA) and Leu13-psi-(CH2NH)Leu14-bombesin (LL-BBS), on BBS-stimulated growth of MC-26 cells in vitro. A possible autocrine role of GRP in the growth of MC-26 cells was also investigated. MC-26 cells were inoculated s.c. into male BALB/c mice, and tumors were harvested 21-28 days postinoculation. Both D-Phe6,BN(6-13)PA and LL-BBS significantly inhibited the binding of 125I-GRP to MC-26 tumor membranes in a dose-dependent manner, with 50% inhibitory concentrations of 4.5 +/- 0.52 nM and 87 +/- 6 nM, respectively. D-Phe6,BN(6-13)PA similarly inhibited the specific binding of 125I-GRP, cross-linked to a approximately 80 kilodalton binding protein on the MC-26 tumor membranes. In order to determine whether the BBS receptor antagonist, D-Phe6,BN(6-13)PA, functioned as an antagonist or an agonist of biological functions, we measured the bioefficacy of D-Phe6,BN(6-13)PA.(ABSTRACT TRUNCATED AT 250 WORDS)

Changes in protein and nonprotein thiol contents in bladder, kidney and liver of mice by the pesticide sodium-o-phenylphenol and their possible role in cellular toxicity

Acute treatment of mice with Na-o-phenylphenol or phenylbenzoquinone, an electrophilic metabolite of o-phenylphenol, resulted in differential depletion of contents of protein and nonprotein thiols in bladder, kidney and liver. Maximum decrease in the levels of protein and nonprotein reduced thiols was observed in bladder (by both agents) and was followed by kidney (by both agents) and liver (phenylbenzoquinone only). The reason for this differential changes in reduced thiol contents remains to be understood. The content of protein and nonprotein disulfides was higher in bladder of mice treated with Na-o-phenylphenol compared to that observed in untreated mice bladder. Phenyl 2,5'-p-benzoquinone mediated in vivo depletion of nonprotein and protein thiols suggests that Na-o-phenylphenol treatment may decrease in vivo thiols via the formation of phenylbenzoquinone. Increased disulfide formation is considered to represent an index of oxidative stress produced by chemical. Increases in the level of protein and nonprotein disulfides in bladder suggest as observed in this study that administration of Na-o-phenylphenol to mice produced oxidative stress in bladder. Products of redox cycling of xenobiotics are known to cause cellular toxicity via altering the homeostasis of thiol status. Therefore, it is concluded that decreases in protein thiol contents either via alkylation and/or oxidation of sulfhydryl groups of proteins and increases in disulfide contents presumably by products of redox cycling of Na-o-phenylphenol may play a role in Na-o-phenylphenol-induced cellular toxicity.

High-affinity binding sites for bombesin on mouse colonic mucosal membranes

Bombesin (BBS) has specific biological effects on colonic mucosal cells, but the presence of BBS receptors on colonic mucosa have not been described to-date. In the present study we examined the mouse colonic mucosal membranes for the presence of specific binding sites for BBS/gastrin releasing peptides (GRP), and characterized the binding kinetics and molecular weight of the specific binding proteins. The radiolabeled ligand (125I-Tyr4-BBS), in the absence or presence of a 1000-fold excess of BBS, was used to establish the optimal binding assay conditions of time, pH and temperature for measuring the maximum number of specific binding sites for BBS related peptides. Under the optimal binding assay conditions, BBS displaced the binding of 125I-Tyr4-BBS in a dose-related manner. A single class of high-affinity binding sites (Kd = 0.23 +/- 0.02 nM) for BBS were measured, with a binding capacity of 27.3 +/- 4.6 fmoles/mg membrane protein. The binding sites were specific for binding BBS/GRP related peptides, since all structurally related peptides inhibited the binding of 125I-Tyr4-BBS in a dose-dependent manner, while structurally unrelated peptides did not compete for the 125I-Tyr4-BBS binding sites. The relative binding affinity (RBA) of BBS/GRP related peptides was determined to be in the order of GRP (14-27) = GRP (18-27) greater than GRP (1-27) greater than neuromedin B greater than BBS. The BBS-receptor antagonists, [Leu13-psi-(CH2NH) Leu14]-BBS (LL-BBS) and D-Phe6, BN(6-13) propylamide (D-Phe6, BN(6-13)-PA), inhibited the specific binding of 125I-Tyr4-BBS to colonic mucosal membranes in a dose-dependent manner.(ABSTRACT TRUNCATED AT 250 WORDS)

Receptors for insulin-like growth factor II in the rat uterus: characterization and variation throughout the estrus cycle

This study was undertaken to identify uterine insulin-like growth factor II receptors and examine the regulation of these receptor levels throughout the estrus cycle. We have demonstrated IGF-II receptors in crude uterine membranes by binding and cross-linking experiments. IGF-II binding to the rat uterine membranes displayed time and temperature dependence and maximum binding was achieved by 2 h at 22 degrees C. Uterine IGF-II binding sites were specific for binding IGF-II peptide and demonstrated negligible binding affinity for IGF-I and no affinity for insulin. The specific anti-IGF-II receptor antibody, R-II-PAB1, blocked the specific [125I]IGF-II binding to uterine membranes in a dose-dependent manner. The characteristics of uterine IGF-II receptor are similar to those reported for other tissues, with a single class of high-affinity binding sites with an apparent dissociation constant of 1.2 +/- 0.5 nmol/l and Beta max of 2.65 +/- 0.41 pmol/mg protein. Affinity cross-linking experiments indicated that the specific binding of [125I]IGF-II in the uterus is associated with a single band of protein with a mol wt of 250 kD. In mature cycling rats, the proestrus uterus had the lowest level of [125I]IGF-II binding per mg membrane protein, without changes in receptor affinity. However, because of greater yield of protein from proestrus uteri, the total [125I]IGF-II binding capacity of the uterus was similar to the other stages of the estrus cycle. These studies demonstrate the presence of authentic IGF-II receptors in the rat uterus and illustrate variations in the concentration of these receptors in the uterus throughout the estrus cycle.

Family characteristics of autistic children: a further report

The personality features of parents of a group of 21 well-functioning autistic children have been described previously. The main characteristics of these parents were social gaucheness and a tendency towards the single-minded pursuit of special, often intellectual, interests. We now present the agreement between research interviewers and clinician in the diagnosis of these parents as schizoid, together with clinical details of those parents rated by both as having definite schizoid traits. The educational functioning of the siblings of the autistic children compared with that of siblings of a matched control group is also reported.

Specific binding and growth effects of bombesin-related peptides on mouse colon cancer cells in vitro

In the present study, we characterized specific binding of bombesin (BBS)/gastrin-releasing peptide (GRP) to mouse colon cancer (MC-26) cells. MC-26 cells were inoculated into male BALB/c mice subdermally, and tumors were harvested from mice 21-28 days postinoculation. Tumor membranes were analyzed for binding to GRP-related peptides, using either 125I-GRP or 125I-tyrosine4-BBS. Under optimal binding assay conditions, BBS displaced specific binding of both 125I-GRP and 125I-tyrosine4-BBS in a dose-dependent manner, and a curvilinear displacement resulted. Specific binding data, analyzed by either a Scatchard or a Lineweaver-Burk plot, demonstrated presence of 2 classes of specific binding sites, arbitrarily named type I and type II sites. Type I sites had a high binding affinity [Kd 0.45 +/- 0.05 nM (SE)] and a relatively low capacity (226 +/- 27 fmol/mg membrane protein), whereas type II sites had a 10-20-fold lower binding affinity and approximately 6-7-fold higher capacity. BBS/GRP binding sites were specific for GRP-related peptides and demonstrated no significant binding affinity for all other unrelated peptides tested. Relative binding affinity of GRP analogues was in the order of GRP (14-27) greater than neuromedin C greater than or equal to BBS greater than or equal to GRP (1-27) greater than neuromedin B (for the later, P greater than 0.05 versus other peptides). Two BBS receptor antagonists, [D-Arg1,D-trp7,9,Leu11]-substance P (spantide) and [Leu13-psi-(CH2NH)Leu14]BBS also inhibited specific binding of 125I-GRP in a dose-dependent manner. Molecular weight of GRP/BBS binding proteins on tumor membranes was determined by cross-linking methods. A major molecular form (greater than 80-90%) (Mr approximately 75,000) and a minor Mr approximately 180,000 band were evident, both under reducing and nonreducing conditions. BBS (0.5-50 nM) demonstrated a significant dose-dependent growth effect on MC-26 cells in vitro, in terms of [3H]thymidine and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide uptake; these studies indicate that the BBS/GRP binding sites on MC-26 cells may serve as functional receptors and mediate the growth effects of BBS on MC-26 cells.

Binding of insulin-like growth factor-I to rat uterus; variations during sensitization and decidualization

IGF-I receptors have been identified and characterized in a variety of tissues. In this study receptors for IGF-I in the rat uterine tissue were identified and characterized. We have demonstrated IGF-I receptors in crude uterine membranes by binding and cross-linking experiments. IGF-I binding to the rat uterine membranes displayed time, temperature and pH dependance, and optimal binding conditions were achieved by 20 h of incubation at 4 degrees C, at a pH of 7.8. Uterine IGF-I binding sites were specific for binding IGF-I peptide and demonstrated less than 100 x lower affinity for insulin. The binding was reversible and Scatchard analysis indicated presence of a single class of binding sites with an apparent dissociation constant of 1.68 +/- 0.24 nmol/l and Bmax of 0.82 +/- 0.1 pmol/mg protein. During estrogen treatment, sensitization and decidualization there was an overall increase of membrane proteins in the uterus and a relative decrease of IGF-I receptors per unit of protein. When expressed on a per uterus basis, there was a progressive increment in total IGF-I binding in estradiol-treated, sensitized, and decidualized uterus compared with controls. These data indicate a possible role for IGF-I in uterine cell multiplication and further differentiation to decidual cells in response to deciduogenic stimuli.

Changes in lipid profiles of liver microsomes of rats following intratracheal administration of DDT or endosulfan

The effect of intratracheal administration of DDT (5 mg/100 g body weight) or endosulfan (1 mg/100 g body weight) to rats for three consecutive days, has been studied on liver lipid metabolism. The administration of DDT but not endosulfan significantly increased the liver weight and the microsomal protein contents. Both DDT and endosulfan treatments significantly increased the contents of microsomal phosphatidylcholine (PC), total-free- and esterified cholesterol. The distribution of unsaturated fatty acids of microsomal PC and PE was increased by DDT treatment. The intratracheal administration of DDT caused fatty infiltration of liver which was probably due to increased synthesis of triglycerides (TG). This is supported by the increased incorporation of radioactive palmitate-1-14C into microsomal TG. However, the increased incorporation of palmitate-1-14C into microsomal PC and phosphatidylethanolamine (PE) after the DDT treatment, was due to the increased transacylation reaction supported by the decreased activity of microsomal phospholipase A. The intratracheal administration of endosulfan did not have pronounced effect on liver fatty infiltration, or transacylation reaction in microsomal PC and PE. However, the results have shown that the treatments of DDT or endosulfan increased the PC contents and the incorporation of radioactive [methyl-3H]choline into PC of microsomes, resulting the increased synthesis of PC via CDPcholine pathway. Thus, the intratracheally administered DDT or endosulfan to rats showed that both the insecticides cause manifestations in the biochemistry of microsomal membrane lipids, although the effects of DDT being more pronounced. Therefore, the translocation effects of these insecticides or metabolites from lung to liver is established.

Profiles of ethanol-induced microsomal alkoxyresorufin (alkoxyphenoxazone) O-dealkylation: comparison with phenobarbital- and Aroclor 1254-induced systems

The O-dealkylation of various substituted alkoxyphenoxazones by liver microsomes from rats chronically fed ethanol is compared with that from pair-fed controls to determine whether there is any catalytic selectivity which could serve as an indicator for induction of cytochrome P-450j. Microsomes derived from animals pretreated with the better characterized inducers phenobarbital and Aroclor 1254 were also studied as positive controls. The specific activities (units/mg microsomal protein) but not the turnover numbers (units/nmol cytochrome P-450) were significantly increased by ethanol ingestion compared to pair-fed controls for methoxy-, ethoxy-, and pentoxy-resorufin O-dealkylation. Ethanol ingestion produced a significant increase in both specific activity and turnover number for the O-dealkylation of benzyloxy-resorufin. The degrees of induction of alkoxyresorufin-O-dealkylation activity measured for EtOH-induced microsomes range from 1.7 for methoxyresorufin to 4.8 for benzyloxyresorufin and are small in comparison to the values for phenobarbital and Aroclor 1254. This pattern of induction suggests that the minor isoforms induced by phenobarbital may be propagated by chronic ethanol ingestion.

Bimodal operation of the ryanodine-sensitive transducer calcium channel

Ryanodine binds to the transducer calcium channel complex that links depolarization of the transverse tubule to calcium release from the terminal cisternae during excitation-contraction coupling of skeletal muscle. Ryanodine exerts a bimodal action on the transducer calcium channel complex depending upon membrane potential and concentration. When the transmembrane potential is at resting level (-90 mV inside cell vs outside), low concentrations of ryanodine 10(-10) M to 10(-8) M favor calcium influx from outside which in turn causes calcium release from the terminal cisternae via calcium operated calcium channels. The leak from the terminal cisternae is insufficient to cause contraction but does cause a large increase in aerobic energy utilization by the Ca-ATPase of the sarcoplasmic reticulum. When the transmembrane potential is made more positive (-40 mV) the transducer channel is opened to the terminal cisternae of sarcoplasmic reticulum and is maintained in an open state by ryanodine allowing calcium efflux from the terminal cisternae to the sarcoplasm. At higher concentrations of ryanodine the transducer-calcium channel becomes open to the terminal cisternae and its store of ionized calcium leaks from the terminal cisternae in sufficient quantities to cause a contracture. The ryanodine-sensitive calcium transducer calcium channel operates in a bimodal manner. At low concentrations less than 10(-4) M the ryanodine-sensitive transducer calcium channel is open to the lumen of the T-tubule and allows calcium to flow in and trigger further calcium release. At higher concentrations the ryanodine-sensitive transducer channel opens to allow a calcium efflux from the terminal cisternae in sufficient quantities to cause contracture.

Differential induction of peroxygenase-dependent microsomal aniline hydroxylase by chronic ethanol ingestion

The liver microsomal-mediated hydroxylation of aniline, which is selectively induced by chronic (EtOH) ingestion, has been studied as a function of NADPH plus dioxygen (O2)- or hydroperoxide-dependent reactions. Consistent with the well-documented induction of aniline hydroxylase following chronic ethanol -ingestion, the results showed selectivity towards aniline hydroxylase by the NADPH plus O2- and tert-butyl hydroperoxide (t-BuOOH)-dependent reactions with microsomes from EtOH-fed rats. On the other hand, the cumene hydroperoxide (CumOOH)-dependent aniline hydroxylase activity was not discriminated between microsomes from EtOH- and pair-fed rats. In parallel experiments with positive controls, CumOOH did show selectivity for phenobarbital (PB)-induced microsomal aniline hydroxylase compared to chow-fed rats. The Kcat/KM values, which indicate the efficiency of enzyme catalysis, for NADPH plus O2-, t-BuOOH, and CumOOH-dependent aniline hydroxylase from EtOH-fed rats were 102, 37, and 5 and from pair-fed rats were 68, 4, and 4 (nmol p-aminophenol/min/nmol cytochrome P-450)/mM aniline, respectively. The relative Kcat/KM ratio for EtOH-fed to that of pair-fed microsomal aniline hydroxylase from NADPH plus O2-, t-BuOOH-, and CumOOH-dependent reactions were 1.5, 7.4, and 1.2, respectively. The present preliminary studies indicate that the catalytic efficiency of EtOH-induced aniline hydroxylase is significantly greater for the t-BuOOH-dependent reaction.

The presence of a 33-40 KDa gastrin binding protein on human and mouse colon cancer

Human and mouse colon cancers have specific binding sites for gastrin and demonstrate a trophic response to gastrin. In the present study we used radiolabeled gastrin (2-17), to determine the molecular weight of gastrin binding proteins (receptors) on mouse and human colon cancers, by cross-linking methods. Crude membrane aliquots prepared from the tumors were radiolabeled with [125I]gastrin (2-17) +/- 1000 fold excess of unlabeled gastrin and cross-linked with 1 mM disuccinimidyl suberate. The cross-linked radiolabeled binding protein complexes were solubilized and subjected to sodium dodecyl sulfate polyacrylamide gel electrophoresis. The autoradiographs of the gels demonstrated the presence of a predominant band of approximately 33-40 KDa gastrin binding protein, that was specific for gastrin analogs. Our present findings thus indicate that specific gastrin binding proteins/gastrin receptors on colon cancers are primarily present as one band with a molecular mass of approximately 33-40 KDa and are specific for gastrin-like peptides.

Efficacy of oral water soluble vitamin K in neonates

Effect of oral water soluble synthetic Vitamin K on prothrombin time was evaluated in 120 full term exclusively breast fed babies. Group A (n = 30) received 1 mg vitamin K (menadione sodium disulphite) intramuscularly at birth, Group B (n = 30) received 0.5 mg intramuscularly, Group C (n = 30) 1 mg orally and Group D (n = 30) did not receive any vitamin K. Prothrombin time (PT) was measured in all between 36-72 hours of age. The PT values in the four Groups A, B, C and D were 17.1 +/- 2.68 seconds, 17.2 +/- 4.42 seconds, 17.0 +/- 2.86 seconds, and 33.1 +/- 12.2 seconds, respectively; the control being 17.0 seconds. The differences between Groups A, B and C were insignificant. Group D babies had a significant prolongation of prothrombin time (p less than 0.001) as compared to the other groups. It is concluded that oral water soluble vitamin K at birth is as good as injectable vitamin K. It is a much simpler form of prophylaxis and avoids intramuscular injection.

Myocardial collagen and mechanics after preventing hypertrophy in hypertensive rats

To determine if a remodeling of the collagen matrix would occur in the absence of hypertrophy and cell necrosis and if such a remodeling could alter active and passive stiffness of the intact myocardium, five rats with genetic hypertension (SHR) were treated (SHRT) with hydralazine for 32 weeks, beginning at four weeks of age, and compared to six age- and sex-matched SHR and seven Wistar-Kyoto genetic control rats (WKY). Left ventricular (LV) weight of SHRT was 17% lower (P less than .001) than that of SHR and 19% higher (P less than .01) than that of WKY. Collagen volume fraction of SHR (13.7 +/- 3.2%) and SHRT (9.9 +/- 1.8%) were greater (P less than .01) than WKY (5.0 +/- 1.9%). Diastolic and systolic stress-strain relations were determined in the isolated heart. A comparison of these relations revealed: 1) a 24% increase in passive stiffness for SHR and SHRT; and 2) a reduced zero-strain intercept (41% to 54%) and slope (36% to 48%) of the developed stress-strain relation for the SHRT. Thus, in SHR, collagen remodeling occurred in the absence of hypertrophy which suggests that the muscular and collagenous compartments of the myocardium are under separate controls. The excess accumulation of collagen in SHR and SHRT leads to abnormal passive stiffness, and the prevention of hypertrophy with hydralazine reduces active stiffness.

Induction of phosphatidylcholine biosynthesis via CDPcholine pathway in lung and liver of rats following intratracheal administration of DDT and endosulfan

The induction of phosphatidylcholine (PC) biosynthesis via the CDPcholine pathway in lung and liver of rats has been shown following the intratracheal administration of 1,1,1-trichloro-2m2-bis(p-chlorophenyl) ethane (DDT) (5 mg/100 g body weight) and endosulfan (1 mg/100 g body weight) for 3 days. Controls received only the vehicle solution (groundnut oil, 0.1 m1/100 g body weight). The treatment of DDT and endosulfan significantly increased the PC contents and the incorporation of radioactive [methyl-3H]choline into PC of lung and liver microsomes. The incorporation of radioactive [methyl-14C]methionine into microsomal PC of lung and liver was not affected significantly by treatment with either of the insecticides. 1,4,5,6,7-hexachloro-5-norbornene-2,3-dimethano cyclic sulfite (endosulfan) administration significantly increased the activity of choline kinase and phosphocholine cytidylyltransferase (both cytosolic and microsomal) of lung, whereas DDT increased the activity of only latter. In liver, both DDT and endosulfan administration significantly increased the activity of choline kinase and phosphocholine cytidylyltransferase (both cytosolic and microsomal). However, the activity of phosphocholinetransferase was not affected in both lung and liver microsomes of rats treated with these insecticides. The PC precursor pool sizes, choline and phosphorylcholine, of lung and liver tissues were not altered by DDT and endosulfan treatments. The present results suggest that the increased level of PC and incorporation of radioactive [methyl-3H]choline into microsomal PC could be the result of increased activity of choline kinase and phosphocholine cytidylyltransferase of lung and liver of rats following intratracheal administration of DDT and endosulfan.

"Thinking aloud" as a strategy to improve clinical decision making

Although "thinking aloud" has been used as a research method to collect data about nurses' knowledge and cognitive processes, it has not been used widely for instruction. We suggest that thinking aloud can be an effective teaching strategy for staff development. Two techniques are described for incorporating thinking aloud into dialogue among experienced nurses and into mentoring activities between experts and novices. An excerpt from a transcript of one nurse's thinking aloud while making a triage decision is presented to illustrate the types of knowledge and cognitive processes that can be elicited and revealed by using this strategy. Potential educational benefits are identified, along with suggestions for implementing thinking aloud as an instructional method.

Personality characteristics of parents of autistic children: a controlled study

Parents of 21 autistic children and of 21 children with other handicaps, matched for sex, age, IQ and father's occupation, were interviewed with a schedule known to discriminate between schizoid and non-schizoid people. Ratings were reliable and the interviewers remained "blind". Parents of autistic children, especially fathers, were significantly more often rated as having schizoid traits. They were also more intellectual.

Alteration of liver microsomal monooxygenases and substrate competition with aniline hydroxylase from rats chronically fed low-fat and high-fat-containing alcohol diets

Male Sprague-Dawley rats fed ethanol (EtOH) 36% of total calories for four weeks in a liquid diet containing either 34% (HF) or 12% (LF) of calories as fat were studied with respect to induction of microsomal monooxygenases (MFO) and substrate competition with EtOH-inducible aniline hydroxylase. The specific activity and turnover of aniline hydroxylase were induced to similar extents by HF-EtOH and LF-EtOH diets. Whereas, both LF-EtOH and HF-EtOH caused a decrease in the turnover of arylhydrocarbon (benzo[a]pyrene) hydroxylase (AHH) and aldrin epoxidase compared to pair-fed (PF) controls, LF-EtOH but not HF-EtOH increased the turnover of ethoxycoumarin and ethoxyresorufin O-deethylase (ECOD and EROD). The increase in ECOD and EROD and the decrease in AHH by EtOH is contrary to the parallel induction of these activities by 3-methylcholanthrene (3-MC) and Aroclor 1254 (Aroclor). Benzo(a)pyrene (BaP) stimulated aniline hydroxylase in the HF-EtOH and PF systems, whereas with LF diet, stimulation was seen only in the EtOH group. Ethoxycoumarin (EC) inhibited aniline hydroxylase by microsomes from EtOH- and pyrazole-treated rats, whereas it stimulated aniline hydroxylase by control microsomes, suggesting that the EC effects were associated with EtOH-inducible cytochrome P-450. Ethoxyresorufin (ER) inhibited aniline hydroxylase in EtOH and PF groups, thus the differential effects of EC were not nonspecific O-deethylase effects. The effects of EtOH feeding on ECOD, EROD, and AHH (ie, substrates for 3-MC-inducible cytochrome P-450) displayed a greater differential between the experimental and control group with the LF- than with the HF-containing diet. The findings suggest that the alteration of certain MFO activities by chronic EtOH ingestion can be modified by the content of dietary fat. Moreover, the competition dynamics of MFO substrates toward EtOH-inducible aniline hydroxylase are altered by EtOH feeding and, in turn, modified by dietary fat.

Trends in rural out-migration at micro level

This study examines the trends in rural out-migration at the household level for various household size groups using the model developed by Singh et al (1982), using data from the 1969 Demographic Survey of Varanisi (Rural) of 2200 households. Section 2 includes the model, while section 3 deals with its applications as well as a short description of data. Section 4 contains 2 migration tables for 2 survey points.

Effect of decapitation and stress on some plasma electrolyte levels in rats

Male Sprague-Dawley rats carrying indwelling jugular catheters were used to compare two methods of blood collection, catheterization or decapitation, for obtaining the plasma levels of several electrolytes. Decapitation resulted in higher levels of Ca2+, Mg2+, and K+ (18%, 23%, and 35% respectively) compared to catheter values. In a second experiment, catheterized rats were used to examine the effect of immobilization and footshock on plasma electrolytes. Both forms of stress elevated Mg2+, whereas only immobilization elevated Ca2+. Post-stress K+ levels were significantly different than control values. These experiments demonstrate that catheterization must be used to obtain true plasma electrolyte levels, and that electrolytes may be selectively altered depending on the nature of the stressor.

Possible role of the transverse tubules in accumulating calcium released from the terminal cisternae by stimulation and drugs

The size of the rapidly exchanging and slowly exchanging Ca2+ pools were estimated in frog sartorius muscles. A new technique using Sr2+ to extract the rapidly exchanging pool was used. The method avoids problems of kinetic analysis. The results showed that stimulation causes Ca2+ to be translocated from a compartment which exchanges with a time constant of 800 min to a compartment that can be washed out in 15 min. This is likely a transfer from the terminal cisternae to the transverse tubule. Calculations show that this would represent 0.9% of the Ca2+ released in each twitch. After 300 twitches produced by a 1-Hz stimulation, this accumulation could have increased the Ca concentration in the transverse tubules to 70 mM. A marked increase of Ca2+ concentration of this magnitude in the transverse tubules would raise the mechanical threshold for excitation--contraction coupling and would decrease the efficiency of coupling between contraction and excitation. This could be the explanation of the fatigue observed during this kind of stimulation.

The effect of diazepam on tension and electrolyte distribution in frog muscle

The effect of diazepam on sartorius muscles of the frog was evaluated. Resting tension in sartorius muscle was not affected by diazepam (5 x 10(-5)M) but twitch tension was increased and tetanus tension decreased. The kinetics of 45Ca efflux were altered by diazepam. The calcium content of the intermediate pool was increased by diazepam (5 x 10(-6)M). When the diazepam concentration was increased (5 x 10(-5)M), the time constant of the slow pool decreased and the 45Ca content of the intermediate pool increased further. It is suggested that diazepam interferes with the calcium sequestering system of the sarcoplasmic reticulum (slow pool) and causes an increase of the calcium content of the myofibrillar space (intermediate pool).

Influence of verapamil on cellular integrity and electrolyte concentrations of ischemic myocardial tissue in the cat

Verapamil, at a dose of 1 mg/kg, was given intravenously to anesthetized cats one hour after coronary artery occlusion. Verapamil significantly reduced mean arterial blood pressure, but produced an increase in heart rate, partially offsetting the reduction in myocardial oxygen demand resulting from the reduction in pressure. Verapamil failed to prevent the elevations in the S-T segment of the electrocardiogram observed in cats subjected to myocardial ischemia (MI) and given only the vehicle for verapamil (i.e., 0.9% NaCl). Moreover, verapamil also did not prevent the accumulation of creatine phosphokinase (CPK) activity in the circulating blood after MI. Nevertheless, verapamil significantly prevented the loss in CPK and in amino-nitrogen observed in the ischemic region of the myocardium, indicating some protective effect on myocardial integrity. The major effects of verapamil on electrolyte content of ischemic myocardial tissue were a decrease in sodium and an increase in potassium. However, calcium gain by the heart was not prevented by verapamil. Verapamil, therefore, exerts a partial degree of protection of the ischemic myocardium but exerts some other effects which do not help prevent the spread of ischemic damage in the myocardium.

A comparative study of fine-needle aspiration cytology and histopathology in salivary gland lesions

Background: A wide variety of benign and malignant tumours originate in the salivary glands and insufficient tumour cells make their diagnosis difficult in some patients. The aim of this study was to evaluate the efficacy of fine-needle aspiration cytology in the diagnosis of salivary gland lesions and to correlate cytological findings with histopathology. Materials and Methods: This was a prospective study done from September 2002 to May 2004. Fine needle aspiration cytology was performed in 58 patients with clinically significant salivary gland masses. Results: Fine needle aspiration cytology categorized 67.24% of the salivary gland lesions as neoplastic and 32.76% as non-neoplastic lesions. Amongst the neoplastic lesions, 76.9% were benign and 23.1% were malignant cases. Histopathological examination revealed that 81.05% of the cases were benign and 18.95% were malignant. Fine needle aspiration cytology had a sensitivity, specificity and diagnostic accuracy of 81.82%, 100% and 96.55%, respectively. The positive predictive value and negative predictive value was 100% and 95.9%, respectively. Conclusion: Fine needle aspiration of the salivary gland is a safe and reliable technique in the primary diagnosis of salivary gland lesions. Although, limitations are encountered while predicting specific lesions on cytology, especially when dealing with cystic and some malignant lesions, this study has shown that fine needle aspiration cytology has a high sensitivity, specificity and diagnostic accuracy in diagnosing salivary gland lesions. Keywords: Salivary glands; Fine needle aspiration cytology; Histopathology DOI: http://dx.doi.org/10.3126/jpn.v1i2.5403 JPN 2011; 1(2): 108-113

Skin follicle types, ratios, and population densities in Rajasthan sheep breeds

Observations are reported of skin follicle types, ratios, population densities, and percentages of medullated fibres in four Rajasthan sheep breeds – Chokla, Marware, Jaisalmere, and Malpura. Data from three body regions – shoulder, side, and breech – were available for a total of 21 sheep, and for 12 more there were observations for at least one of the three regions. The Chokla breed had the highest total and highest primary follicle population density (9.4 and 3.1 per mm2 respectively), as well as the highest ratio of secondary to primary follicles (2.1) and the lowest percentage medullation (24 per cent. of all fibres, 2 per cent. of secondary fibres). The Malpura breed had the lowest total and lowest primary follicle population density (5.6 and 2.5 per mm2), and was equal with the Marware breed for the lowest ratio (1.3). The Malpura breed had the highest percentage medullation (77 per cent. of all fibres, 60 per cent. of secondary fibres). Of the three body regions studied, the side had the highest ratio of secondary to primary follicles in all four breeds, while the breech had the highest percentage of medullated secondary fibres. The percentage of medullated primary fibres in the breech was equal to or greater than that in either of the other regions.