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Query: UMLS:C0040822 (tremor)
 18,428 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Using 20 strains of Pseudomonas aeruginosa isolated from patients, production of protease, elastase, and collagenase was determined by shaking culture in either complex or semisynthetic medium. No collagenase was produced by any strain of P. aeruginosa. According to their production of protease and elastase in different media, the P. aeruginosa strains were divided into three groups: the first group can produce elastase in complex medium and both protease and elastase in semisynthetic medium; the second group cannot produce any proteolytic enzymes in complex medium but can produce any proteolytic enzymes in either medium; and the third group cannot produce any proteolytic enzymes in either medium. In spite of the differences in the ability of the strains to produce the enzymes, depending upon the origin of the strains, the protease or elastases produced in different broths were regarded as identical.
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PMID:Production of protease and elastase by Pseudomonas aeruginosa strains isolated from patients. 1 45

Suspensions of endocrine pancreas cells were prepared by shaking collagenase-isolated rat islets of Langerhans in calcium-free buffer. When incubated with 1.0 mM substrate at pH 7.4, the cells split Pi from 5'-AMP at a rate of 87 nmol/h per microgram DNA, and from beta-glycerophosphate at a rate of 25 nmol/h per microgram DNA. Km for 5'-AMP was about 54 microM. Adenosine or theophylline inhibited the 5'-AMP hydrolysis. Homogenization of the cells increased the activity toward 5'-AMP by 23% and that toward beta-glycerophosphate by 115%. Injecting rats with cortisone had no effect on the 5'-AMP hydrolysis by whole cells but significantly increased the activity in cell homogenates; the intracellular activity toward 5'-AMP was more than doubled by the cortisone treatment. Staining whole islet cells for 5'-AMP-splitting activity resulted in a demarcation of the cell periphery in control rats. Cells from cortisone-treated rats showed heavier deposits of reaction product, and their cell periphery did not stand out as clearly. It is suggested that 5'-nucleotidase is largely an ectoenzyme in normal rat islet cells. The cells also contain an as yet unidentified intracellular phosphatase that seems to be solely responsible for the increased hydrolysis of 5'-AMP in cortisone-treated rats.
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PMID:5'-AMP hydrolysis by suspensions and homogenates of pancreatic islet cells from normal and cortisone-treated rats. 38 76

To determine and compare the direct effects of prostaglandin F2a (PGF2a) and human chorionic gonadotropin (hCG) on luteal cell progesterone production in vitro, 9 human corpora lutea obtained at tubal ligation were minced and treated with collagenase to disaggregate luteal cells. Dispersed luteal cells (80% viable) were incubated in air at 37 degrees C in a shaking water bath for 3 h and total progesterone in the media and cells was determined by radioimmunoassay. Optimum progesterone production was obtained using 25,000 or more cells per incubate and an incubation time of 2-4 h. hCG-stimulated progesterone production increased significantly with 0.01 IU to as high as 100 IU. In the early luteal phase (days 1-5 post ovulation or days 15-20 of the luteal phase), PGF2a (10-1000 ng) significantly inhibited progesterone production but significantly stimulated progesterone production in the mid-luteal phase (days 21-25). PGF2a had no effect on luteal cell progesterone production in the late luteal phase (days 26-30). This age-dependent direct effect of PGF2a on human luteal cell progesterone production in vitro indicates a role for PGF2a in the total intragonadal regulation of progesterone output, possibly through a paracrine or autocrine manner directed towards synchronizing luteal progesterone secretion and endometrial preparation for nidation.
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PMID:Effect of human chorionic gonadotropin and prostaglandin F2a on progesterone production by human luteal cells. 260 39

A new method for preparation of viable islet cells from the normal pancreas is introduced. After total pancreatectomy, the pancreatic duct is cannulated and perfused with Hanks' balanced salt solution (HBSS) containing 0.2% collagenase at 37 degrees C for 30-45 minutes. The gland is then chopped and dissociated by shaking in a water bath. The cell suspension is filtered through steel mesh and washed with cold HBSS by centrifugation. By this method, collagenase is applied preferentially into the acinar tissue and the islet yield is greatly enhanced with decreased acinar contamination. Estimation of insulin and amylase in pancreatic tissue and islet rich cell suspension (graft) indicates a 57% islet recovery and a six-fold enrichment in islet concentration. Graft prepared by this method is autotransplanted into totally pancreatectomised dogs and normoglycemia is achieved in ten of 13 animals.
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PMID:[A new method for preparation of islet cells from dogs]. 298 34

The characteristics of the steroidogenic response of reaggregated rat interstitial cells were examined in a perifusion system. Interstitial cells were isolated from 19-day-old rat testes by digestion with collagenase. The cells were cultured for 3 days as monolayers and were resuspended by brief treatment with trypsin. Constant gyratory shaking of the dispersed cells resulted in the formation of round and compact aggregates of 70-140 microns. The functional characteristics of these aggregates were examined by studying the output of cAMP, C19 steroids (testosterone and androstenedione), and C21 steroids (progesterone, 17 alpha-hydroxyprogesterone, 20 alpha-hydroxypregn-4-en-3-one) in a perfusion system. It is demonstrated that reaggregated interstitial cells maintain their responsiveness to LH, LHRH, and Leydig cell stimulatory factor(s) produced by Sertoli cells for at least 12 days. When exposed to low concentrations of LH (1 ng/ml), either in a continuous or in a pulsatile fashion, perifused aggregates maintain a constant output of steroids for more than 20 h. Under these conditions, LH-dependent differentiation of the steroidogenic machinery can be observed in vitro. In fact, although the sum of the measured steroids remains constant, C21 steroids progressively decrease whereas C19 steroid output increases during perifusion. When perifused with high concentrations of LH (10 ng/ml), desensitization becomes the predominant phenomenon. It is demonstrated that the steroid output of reaggregated interstitial cells considerably exceeds that of similarly treated cells maintained as monolayers. Moreover, perifusion of aggregates results in a 6-fold increase in steroid output as compared to static incubation and in a selective increase in androgen output. It is concluded that prepubertal interstitial cells allowed to reaggregate in suspension culture form functional multicellular structures. Perifusion of these aggregates is a useful tool in the study of the dynamics of the regulation of steroidogenesis.
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PMID:The dynamics of steroid and adenosine 3',5'-cyclic monophosphate output in perifused interstitial cell aggregates derived from prepubertal rat testes. 301 35

Benzyl chloride (BCl) is used in the manufacture of basic and acidic dyes, pharmaceutical products, resins, and synthetic tannins. BCl is known to have caused liver malfunctions in some workers exposed to 2 ppm BCl vapors. This study was conducted to investigate the effect of BCl on isolated male rat hepatocytes using several toxicity parameters. The hepatocytes were isolated by a collagenase perfusion technique and were incubated in airtight tubes with 1.8 and 3.6 mM BCl in a shaking water bath at 37 degrees C for 10, 30, 60, and 120 min. Throughout the incubation period the cell viability was determined by trypan blue exclusion and leakage of cytosolic enzymes such as lactate dehydrogenase (LDH), aspartate transaminase (AST), and alanine transaminase (ALT). Exposure to BCl resulted in a significant decrease in cell viability as assessed by trypan blue and significant increase in leakage of these enzymes compared to the controls.
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PMID:Effect of benzyl chloride on rat hepatocytes. 319 58

Trout testes at various stages of maturation were dissociated by perfusion at 12 degrees C with collagenase plus pronase and then with collagenase alone, followed by slight shaking overnight in 1% bovine albumin. This step provided a suspension of isolated somatic and germ cells, clusters of interstitial cells, and either intact spermatogenetic cysts (meiotic testes) or clusters of Sertoli cells (other testes). Most of the spermatozoa were removed from the testis cell suspension by centrifugation in Percoll (density 1.065 g/ml). Sertoli and Leydig cells were prepared by a two-step separation method: 1) the testis cell suspension was separated by sedimentation at unit gravity into "isolated cell" and "cell cluster" populations; 2) these populations were fractionated by isopyknic centrifugation in Percoll gradients. In terms of somatic cell composition, a nearly pure Sertoli cell (clusters) population was obtained between 1.017 and 1.033 g/ml and a Leydig cell (clusters) enriched population of between 1.033 and 1.048 g/ml (testes resuming spermatogenesis) or 1.048 and 1.062 g/ml (other testes). These various cell populations were cultured in modified Leibovitz L15 medium for 10-15 days. When seeded, the Sertoli cells had a normal ultrastructure that remained unchanged for at least 10 days, and the steroidogenic activity of Leydig cells could be stimulated by salmon gonadotropin. Leydig cells remained 3 beta-HSD positive and produced progesterone and 17 alpha, 20 beta-OH progesterone for at least 11 days. This study points out that viable and differentiated trout somatic testicular cells can be prepared and cultured for several days.
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PMID:Trout Sertoli and Leydig cells: isolation, separation, and culture. 323 52

The objectives of this study were to establish a suitable and validated in vitro bioassay of piscine gonadotropins (GTHs) by using a carp testis androgen production system and to compare the androgenic responses in such an assay to gonadotropins from various vertebrate species. The testes from mature carp with gonadosomatic indices of 8-30% were used. Androgen production was first compared with respect to methods for preparation of the carp testis (sliced, minced, homogenized, and collagenase-dispersed testis preparations). The time course of androgen formation, the effects of xanthine and theophylline, and other factors on androgen production also were investigated. Theophylline was more effective than xanthine in potentiation of gonadotropin-evoked androgen formation by carp testis. The testis preparations were incubated in medium 199 (pH 7.40) containing 2 mM theophylline with shaking at 100 cycles/min at 25 degrees C for 4 hr. Homogenized testis preparations had limited ability for androgen production, while sliced, minced, and minced-collagenase-dispersed testis preparations were highly responsive to gonadotropins for androgen production. The minced testis preparation, utilizing 100 mg/ml incubation medium per vial, was chosen as the standard incubation procedure in this study. The minced testis androgen production assay was highly sensitive to gonadotropins from several piscine species (silver carp, common carp, and salmon), and all these GTHs produced parallel dose-related androgen production curves. Mammalian GTHs were also capable of promoting androgen formation by carp testis, but they were much less potent than were piscine GTHs. Pregnant mares' serum gonadotropin (PMSG) was more effective than human chorionic gonadotropin (hCG) in evoking carp testis androgen production.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Species variation of gonadotropic activity in an in vitro assay measuring androgen formation by carp (Cyprinus carpio) testis with special reference to bioassay of piscine gonadotropins. 377 Apr 34

1. A method for measuring the lipogenesis from [(14)C]glucose by single fat cells is described: (i) after incubation with ;carrier-free' [U-(14)C]glucose (0.55 mu-mole/ml.), collagenase-isolated fat cells were fixed with osmium tetroxide; (ii) similarly incubated pieces of epididymal fat pads were treated with osmium tetroxide for 90 sec, whereby only the superficial cells are fixed, and the tissue was then disintegrated by shaking with collagenase. The osmium-fixed free cells were washed, sucked into a micropipette, measured under a microscope and assayed individually for (14)C-activity.2. There was a quantitative recovery of (14)C-lipid activity from osmium-fixed single cells.3. Both collagenase-isolated cells and in situ fixed surface cells were normally distributed with respect to diameters (for both cell groups from ad lib. fed rats of ca. 110 g; mean diameter, about 55 mum; S.D. about 7 mum).4. Frequency distribution curves (number of fat cells versus (14)C-lipogenesis per cell) were asymmetric and very broad (coefficient of variation about 50%) for collagenase-isolated cells incubated with insulin (10(3) mu-u./ml.). Frequency distribution curves for surface cells obtained from similarly incubated pieces of epididymal fat pads showed a coefficient of variation of the same magnitude, whereas the mean lipogenesis of these cells was only about one third of that of the isolated cells.5. Collagenase-isolated cells incubated in the presence of insulin (10(3) mu-u./ml.) showed a weak but highly significant positive correlation between fat cell diameter and (14)C-lipogenesis (eight rats, r about 0.5 and P < 0.001 for each rat). Analysis of the relationship: lipogenesis = k x diameter to the exponent of beta showed that the estimates of beta varied significantly from rat to rat (range: 1.3-2.9). Similar correlations between cell size and lipogenesis were found both for cells incubated with insulin in various submaximal concentrations and for cells incubated without insulin.6. Small and large cells from the same rat were equally sensitive to insulin.7. Statistical analysis of frequency distribution curves (number of cells versus (14)C-lipogenesis per unit surface area) representing cells from the same rat incubated with insulin 0, 2.5, 5, 10, and 10(3) mu-u./ml., respectively, suggests that insulin exerts a graded influence on the lipogenesis of each fat cell.
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PMID:Lipogenesis and insulin sensitivity of single fat cells. 436 2

A new technique employing continuous recirculating perfusion of the rat liver in situ, shaking of the liver in buffer in vitro, and filtration of the tissue through nylon mesh, results in the conversion of about 50% of the liver into intact, isolated parenchymal cells. The perfusion media consist of: (a) calcium-free Hanks' solution containing 0.05% collagenase and 0.10% hyaluronidase, and (b) magnesium and calcium-free Hanks' solution containing 2 mM ethylenediaminetetraacetate. Biochemical and morphologic studies indicate that the isolated cells are viable. They respire in a medium containing calcium ions, synthesize glucose from lactate, are impermeable to inulin, do not stain with trypan blue, and retain their structural integrity. Electron microscopy of biopsies taken during and after perfusion reveals that desmosomes are quickly cleaved. Hemidesmosome-containing areas of the cell membrane invaginate and appear to pinch off and migrate centrally. Tight and gap junctions, however, persist on the intact, isolated cells, retaining small segments of cytoplasm from formerly apposing parenchymal cells. Cells which do not retain tight and gap junctions display swelling of Golgi vacuoles and vacuoles in the peripheral cytoplasm. Cytoplasmic vacuolization in a small percentage of cells and potassium loss are the only indications of cell injury detected. By other parameters measured, the isolated cells are comparable to normal hepatic parenchymal cells in situ in appearance and function.
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PMID:High-yield preparation of isolated rat liver parenchymal cells: a biochemical and fine structural study. 490 Jun 11


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