PREVALENCE, IN-VITRO SECRETORY ACTIVITY, AND CYTOTOXICITY OF AEROMONAS SPECIES ASSOCIATED WITH CHILDHOOD GASTRO-ENTERITIS IN CHENNAI (MADRAS), INDIA

Autosomal dominant polycystic kidney disease (ADPKD) is characterized by progressive renal enlargement, culminating in renal insufficiency in over one half of affected individuals. The highly variable onset and clinical course of ADPKD may be due to factors extrinsic to the genetically defined renal cysts. In this study, cyst fluid samples from 12 nonazotemic and 18 azotemic ADPKD subjects were examined for in vitro biologic activity that promotes cellular proliferation and the secretion of fluid by renal epithelial monolayers, two pathogenetic mechanisms that have critical roles in the formation and the rate of expansion of renal cysts. Cyst fluid added to culture medium (final concentrations, 1 to 20%) caused Madin-Darby canine kidney cells and human kidney cortex (HKC) cells derived from primary cultures to form cysts in Type I collagen matrix. Cyst fluid stimulated the net transepithelial secretion of fluid by polarized monolayers composed of these same cells. Absolute levels of fluid secretory activity determined by MDCK bioassay were correlated directly with the rate of fluid secretion by HKC cell monolayers and with the extent of cyst formation by MDCK and HKC cells embedded in collagen matrix. The secretory activity of urine was negligible; secretory activity was detectable in the serum of normal and ADPKD subjects, but the levels were much lower than in cyst fluid. cAMP agonists prostaglandins E1 and E2, arginine vasopressin, and 8-Br-cAMP stimulated fluid secretion by MDCK and HKC monolayers, but these substances did not cause HKC cells to form cysts in collagen matrix, whereas cyst fluid did. Among other naturally occurring growth factors and autacoids, only epidermal growth factor and transforming growth factor alpha stimulated cyst formation by HKC cells; however, the capacity of cyst fluid to stimulate fluid secretion was not affected by treatment with antiserum to epidermal growth factor. It was concluded that potent, and possibly unique, substances in the cyst fluids of individuals with ADPKD support and augment biologic processes in renal epithelial cells that may be important in the promotion of progressive cyst expansion.

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N-Acetylcysteine and Sulodexide Reduce the Prothrombotic Effect of Uremic Serum on the Venous Endothelial Cells

Kidney & Blood Pressure Research ◽

10.1159/000499879 ◽

2019 ◽

Vol 44 (2) ◽

pp. 277-285

Author(s):

Patrycja Sosinska-Zawierucha ◽

Beata Mackowiak ◽

Andrzej Breborowicz

Keyword(s):

Gene Expression ◽

Renal Failure ◽

Endothelial Cells ◽

Ex Vivo ◽

Secretory Activity ◽

Serum Samples ◽

Uremic Serum ◽

Uremic Patients ◽

End Stage

Background/Aims: Thromboembolic episodes are a frequent problem in end stage renal failure patients. The pathomechanism of the disorder is complex, including bioincompatibility of renal replacement therapy, endothelial dysfunction, increased blood level of procoagulant factors and uremic toxins. We studied changes in the functional properties of venous endothelial cells (VEC) in the presence of uremic serum and evaluated their possible modulation by N-acetylcysteine (NAC) or sulodexide (SUL). Methods: Serum samples from 12 uremic patients treated with hemodialysis were studied ex vivo on in vitro cultured VEC. In separate experiments, NAC 1 mmol/L or SUL 0.5 LRU/mL were added to uremic serum samples. Both changes in the gene expression and secretory activity of VEC were studied. Results: Uremic serum increased the expression of the following genes: IL6 +97%, p < 0.002; VEGF +28%, p < 0.002; vWF +47%, p < 0.002; PECAM +76%, p < 0.002; ICAM-1 +275%, p < 0.002; t-PA +96%, p < 0.002. Changes in gene expression were reflected by the increased secretory activity of VEC treated with the uremic serum. Exposure of VEC to uremic serum supplemented with NAC or SUL resulted in weaker stimulation of the studied genes’ expression. Also, secretion of the studied solutes, with the exception of ICAM-1, was reduced in the presence of NAC: IL6 –34%, p < 0.01; VEGF –40%, p < 0.005; vWF –25%, p < 0.001; t-PA –47%, p < 0.01, and MMP9 –37%, p < 0.001. SUL reduced the uremic serum-induced secretion of all solutes: IL6 –24%, p < 0.05; ICAM-1 –43%, p < 0.01; VEGF –38%, p < 0.01; vWF –23%, p < 0.01; t-PA –49%, p < 0.01, and MMP9 –25%, p < 0.05. Conclusions: Uremic serum induces prothrombotic changes in VEC, which may cause a predisposition to thrombotic disorders in patients with renal failure. NAC and SUL reduce the effects of the uremic serum in VEC, which suggests their potential therapeutic application in uremic patients.

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“IN VIVO” AND “IN VITRO” EFFECT OF ASCORBIC ACID AND ACTH ON THE RAT ADRENAL CORTEX

Canadian Journal of Medical Sciences ◽

10.1139/cjms52-023 ◽

1952 ◽

Vol 30 (3) ◽

pp. 157-162

Author(s):

A. DesMarais ◽

J. Leblanc

Keyword(s):

Ascorbic Acid ◽

Adrenal Cortex ◽

Adrenal Glands ◽

Secretory Activity ◽

In Vitro Experiments ◽

Hypophysectomized Rats ◽

Vitro Effect ◽

Histochemical Examination

Histochemical examination of adrenal glands of hypophysectomized rats given both ascorbic acid and ACTH showed an enlargement of the cortex and a decrease of sudanophilic substances, as compared to adrenals of hypophysectomized rats receiving ACTH alone. “In vitro” experiments on incubated slices of adrenal glands have shown that ascorbic acid and ACTH have a synergistic effect on the secretory activity of the cells of the adrenal cortex.

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The in vitro secretion of human leptin is gender-dependent but independent of the body mass index of the donors

Acta Endocrinologica ◽

10.1530/eje.0.1430711 ◽

2000 ◽

pp. 711-714 ◽

Cited By ~ 14

Author(s):

C Menendez ◽

R Baldelli ◽

M Lage ◽

X Casabiell ◽

V Pinero ◽

...

Keyword(s):

Body Mass Index ◽

Adipose Tissue ◽

Body Mass ◽

Tissue Sample ◽

Secretory Activity ◽

The Body ◽

Secretory Rate ◽

Omental Adipose Tissue

OBJECTIVE: Leptin is an adipocyte-secreted hormone acting as a signal to the central nervous system, where it regulates energy homeostasis and neuroendocrine processes. Leptin plasma levels are mainly regulated by the percentage of body fat, but are also controlled by several metabolic and nutritional variables. Data regarding leptin secretion suggest that it is gender regulated, and higher levels are present in women than men; however, the biological basis for this sex-related difference is unknown. To clarify those points, a systematic study with tissue cultures from human omental adipose tissue was performed. DESIGN AND METHODS: Surgically obtained samples from 137 patients (68 women, 69 men) were evaluated. The assay was standardized in periods of 24 h ending at 96 h. Each adipose tissue sample from a single donor was incubated in triplicate and leptin results expressed as the mean of the integrated secretion into the medium (nanograms of leptin/g tissue per time). RESULTS: Tissue adipose cultures showed a steady leptin secretion throughout the 96 h studied, with the peak of secretory activity reached at 48 h; afterwards, the in vitro secretion reached a plateau state. Spontaneous leptin secretion in the 24 h and 48 h period, as well as the area under the curve analyzed in the 0-48 h period, showed a gender-based difference that was significantly (P<0. 05) higher in women than in men. When data of spontaneous leptin secretion were correlated with the body mass index (BMI) of the donors, no correlation was found. This suggests that in vivo leptin levels are dependent on the total amount of fat of the individual, but independent of the leptin secretory rate by the adipose tissue of the donor. CONCLUSIONS: Leptin secretion from omental adipose tissue in vitro is: (i) significantly higher in samples from women than in samples from men; and (ii) not correlated with the BMI, showing that in vitro leptin secretion is not related to the adiposity of the donor.

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Reversible effects of phenothiazines on frog gastric stimulation

AJP Gastrointestinal and Liver Physiology ◽

10.1152/ajpgi.1984.247.4.g366 ◽

1984 ◽

Vol 247 (4) ◽

pp. G366-G376

Author(s):

N. Raphael ◽

E. B. Ekblad ◽

T. E. Machen

Keyword(s):

Adenylate Cyclase ◽

Time Course ◽

Phosphodiesterase Inhibitor ◽

Secretory Activity ◽

Gastric Stimulation ◽

Camp Content ◽

Oxyntic Cell ◽

Camp Generation ◽

Stimulus Secretion Coupling

The calmodulin inhibitors trifluoperazine (TFP), chlorpromazine (CPZ), and promethazine (PZ) were tested for effects on stimulus-secretion coupling in in vitro bullfrog gastric mucosa. When added to histamine-stimulated tissues, the drugs caused H+ secretion to decrease and transepithelial resistance to increase over a 2-h time course. The potency sequence was TFP (IC50 = 40 microM) greater than CPZ (IC50 = 72 microM) congruent to PZ (IC50 = 72 microM). Anesthetics and other phenothiazines with weak anticalmodulin activity had no effect on secretory parameters. In the presence of histamine, further addition of isobutylmethylxanthine (IBMX, a phosphodiesterase inhibitor) plus dibutyryl cAMP (DBcAMP), IBMX alone, or forskolin (a specific activator of adenylate cyclase) to phenothiazine-inhibited tissues caused full resumption of secretory activity. If TFP (50 microM) was added before stimulation with histamine, the normal increases in tissue cAMP content (which occurs primarily in oxyntic cells), oxyntic cell apical membrane elaboration (morphometric analysis of electron micrographs), and H+ secretion were all blocked. Subsequent addition of IBMX or IBMX plus DBcAMP completely reversed the TFP effect. These results indicate that the histamine-sensitive adenylate cyclase may be the site of TFP inhibition and Ca2+-calmodulin regulation; since these drugs inhibited stimulation by DBcAMP plus IBMX, they may also be exerting additional effects distal to cAMP generation.

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Serum deprivation affects secretory activity of cultured porcine ovarian follicles and granulosa cells and their response to hormones

Veterinární Medicína ◽

10.17221/112/2009-vetmed ◽

2009 ◽

Vol 54 (No. 10) ◽

pp. 455-460

Author(s):

A.V. Sirotkin

Keyword(s):

Granulosa Cells ◽

Ovarian Follicle ◽

Secretory Activity ◽

Ovarian Follicles ◽

Serum Deprivation ◽

Ovarian Cells ◽

Igf I ◽

Granulose Cells ◽

Vitro Model

The aim of the present study is to understand the hormonal mechanisms of the effect of malnutrition on ovarian follicle functions. For this purpose, we examined the effect of malnutrition/serum deprivation, addition of metabolic hormones and gonadotropin (IGF-I, leptin and FSH) and their combination on the release of progesterone (P4), testosterone (T), estradiol (E2) and insulin-like growth factor I (IGF-I) by cultured whole ovarian follicles and on P4 and IGF-I output by cultured granulosa cells isolated from porcine ovaries. It was observed that in ovarian follicles cultured with nutrients/serum addition of IGF-I reduced release of P4, but not of T or E2. Exogenous leptin reduced output of E2, but not of P4 or T, and increased IGF-I output. No significant effect of FSH on release of steroid hormones by isolated follicles was found. Serum deprivation did not affect release of P4, but reduced output of T and E2, and promoted IGF-I release by cultured ovarian follicles. Addition of hormones failed to prevent the effect of malnutrition on the secretory activity of cultured ovarian follicles. In cultured granulose cells, all the tested hormones promoted release of both P4 and IGF-I. Food restriction/serum deprivation reduced both P4 and IGF-I output. Additions of either IGF-I, leptin and FSH prevented the inhibitory action of malnutrition on both P4 and IGF-I release. The present observations (1) confirm the involvement of the hormones IGF-I, leptin and FSH in the control of secretory activity of ovarian cells, (2) demonstrate, that both isolated ovarian granulosa cells and whole follicles cultured in the absence of serum nutrients could be an adequate in-vitro model for studying the effect of malnutrition on ovarian secretory functions, and (3) suggest, that malnutrition could affect ovarian functions through changes in the release of ovarian hormones.

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Membrane biogenesis during B cell differentiation: most endoplasmic reticulum proteins are expressed coordinately.

The Journal of Cell Biology ◽

10.1083/jcb.110.5.1501 ◽

1990 ◽

Vol 110 (5) ◽

pp. 1501-1511 ◽

Cited By ~ 149

Author(s):

D L Wiest ◽

J K Burkhardt ◽

S Hester ◽

M Hortsch ◽

D I Meyer ◽

...

Keyword(s):

B Cell ◽

Secretory Activity ◽

High Rate ◽

B Cell Differentiation ◽

Golgi Stack ◽

Membrane Bound ◽

Rough Er ◽

Secretory Apparatus ◽

Area And Volume

The induction of high-rate protein secretion entails increased biogenesis of secretory apparatus organelles. We examined the biogenesis of the secretory apparatus in the B cell line CH12 because it can be induced in vitro to secrete immunoglobulin (Ig). Upon stimulation with lipopolysaccharide (LPS), CH12 cells increased secretion of IgM 12-fold. This induced secretion was accompanied by preferential expansion of the ER and the Golgi complex. Three parameters of the rough ER changed: its area and volume increased 3.3- and 3.7-fold, respectively, and the density of membrane-bound ribosomes increased 3.5-fold. Similarly, the area of the Golgi stack increased 3.3-fold, and its volume increased 4.1-fold. These changes provide sufficient biosynthetic capacity to account for the increased secretory activity of CH12. Despite the large increase in IgM synthesis, and because of the expansion of the ER, the concentration of IgM within the ER changed less than twofold during the differentiation process. During the amplification of the rough ER, the expression of resident proteins changed according to one of two patterns. The majority (75%) of rough microsomal (RM) proteins increased in proportion to the increase in rough ER size. Included in this group were both lumenal proteins such as Ig binding protein (BiP), and membrane proteins such as ribophorins I and II. In addition, the expression of a minority (approximately 9%) of RM polypeptides increased preferentially, such that their abundance within the RM of secreting CH12 cells was increased. Thus, the expansion of ER during CH12 differentiation involves preferential increases in the abundance of a few resident proteins, superimposed upon proportional increases in most ER proteins.

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LIMITATIONS OF THE IN VITRO PITUITARY INCUBATION SYSTEM AS AN ASSAY FOR ACTH-RELEASING ACTIVITY

Canadian Journal of Biochemistry and Physiology ◽

10.1139/o58-014 ◽

1958 ◽

Vol 36 (1) ◽

pp. 111-118 ◽

Cited By ~ 6

Author(s):

Claude Fortier ◽

Darrell N. Ward

Keyword(s):

Blood Serum ◽

Physiological State ◽

In Vitro Release ◽

Secretory Activity ◽

Physiological Significance ◽

Incubation System ◽

Serum Fractions ◽

Apparent Relationship ◽

Vitro Release

The applicability of Saffran and Schally's in vitro pituitary incubation technique to the detection of the ACTH-releasing activity of blood serum fractions, obtained from intact, stressed, adrenalectomized, and stressed–adrenalectomized donor rats, was investigated. The various fractions assayed in this system were found to be markedly active. The activity, which bore no apparent relationship to the physiological state of the donors, was related in part to inhibition of ACTH inactivation, in part to enhanced release of ACTH by the incubated pituitaries. In view of the non-specificity of the observed responses, it is suggested that the increased in vitro release of ACTH may reflect passive leakage of the hormone, as opposed to true secretory activity, and the physiological significance of findings obtained with this method is seriously questioned.

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