Lactiplantibacillus plantarum 299v (LP299V®): three decades of research

This review aims to provide a comprehensive overview of the in vitro, animal, and clinical studies with the bacterial strain Lactiplantibacillus plantarum 299v (L. plantarum 299v; formerly named Lactobacillus plantarum 299v) published up until June 30, 2020. L. plantarum 299v is the most documented L. plantarum strain in the world, described in over 170 scientific publications out of which more than 60 are human clinical studies. The genome sequence of L. plantarum 299v has been determined and is available in the public domain (GenBank Accession number: NZ_LEAV01000004). The probiotic strain L. plantarum 299v was isolated from healthy human intestinal mucosa three decades ago by scientists at Lund University, Sweden. Thirty years later, a wealth of data coming from in vitro, animal, and clinical studies exist, showing benefits primarily for gastrointestinal health, such as reduced flatulence and abdominal pain in patients with irritable bowel syndrome (IBS). Moreover, several clinical studies have shown positive effects of L. plantarum 299v on iron absorption and more recently also on iron status. L. plantarum 299v is safe for human consumption and does not confer antibiotic resistance. It survives the harsh conditions of the human gastrointestinal tract, adheres to mannose residues on the intestinal epithelial cells and has in some cases been re-isolated more than ten days after administration ceased. Besides studying health benefits, research groups around the globe have investigated L. plantarum 299v in a range of applications and processes. L. plantarum 299v is used in many different food applications as well as in various dietary supplements. In a freeze-dried format, L. plantarum 299v is robust and stable at room temperature, enabling long shelf-lives of consumer healthcare products such as capsules, tablets, or powder sachets. The strain is patent protected for a wide range of indications and applications worldwide as well as trademarked as LP299V^®.

Heparin-binding protein in ventilator-induced lung injury

Background

Although mechanical ventilation is often lifesaving, it can also cause injury to the lungs. The lung injury is caused by not only high pressure and mechanical forces but also by inflammatory processes that are not fully understood. Heparin-binding protein (HBP), released by activated granulocytes, has been indicated as a possible mediator of increased vascular permeability in the lung injury associated with trauma and sepsis. We investigated if HBP levels were increased in the bronchoalveolar lavage fluid (BALF) or plasma in a pig model of ventilator-induced lung injury (VILI). We also investigated if HBP was present in BALF from healthy volunteers and in intubated patients in the intensive care unit (ICU).

Methods

Anaesthetized pigs were randomized to receive ventilation with either tidal volumes of 8 ml/kg (controls, n = 6) or 20 ml/kg (VILI group, n = 6). Plasma and BALF samples were taken at 0, 1, 2, 4, and 6 h. In humans, HBP levels in BALF were sampled from 16 healthy volunteers and from 10 intubated patients being cared for in the ICU.

Results

Plasma levels of HBP did not differ between pigs in the control and VILI groups. The median HBP levels in BALF were higher in the VILI group after 6 h of ventilation compared to those in the controls (1144 ng/ml (IQR 359–1636 ng/ml) versus 89 ng/ml (IQR 33–191 ng/ml) ng/ml, respectively, p = 0.02).

The median HBP level in BALF from healthy volunteers was 0.90 ng/ml (IQR 0.79–1.01 ng/ml) as compared to 1959 ng/ml (IQR 612–3306 ng/ml) from intubated ICU patients (p < 0.001).

Conclusions

In a model of VILI in pigs, levels of HBP in BALF increased over time compared to controls, while plasma levels did not differ between the two groups.

HBP in BALF was high in intubated ICU patients in spite of the seemingly non-harmful ventilation, suggesting that inflammation from other causes might increase HBP levels.

Electronic supplementary material

The online version of this article (10.1186/s40635-018-0198-x) contains supplementary material, which is available to authorized users.

Percutaneously inserted long-term central venous catheters in pigs of different sizes

Pigs are used for long-term biomedical experiments requiring repeated injections, infusions and collections of blood samples. Thus, it is necessary for vascular catheters to be indwelling to avoid undue stress to the animals and the use of restraints. We propose a refined model of percutaneous insertion of long-term central venous catheters to minimize the surgical trauma and postoperative complications associated with catheter insertion. Different sizes of needles (18 Ga versus 21 Ga) for initial puncture of the veins were compared. In conventional pigs weighing less than 30 kg, catheter insertion may be facilitated by using a microintroducer set with a 21 Ga needle. In pigs weighing 50 kg, a standard 18 Ga needle may be preferable.

The orphan receptor GPR55 is a novel cannabinoid receptor

BACKGROUND

The endocannabinoid system functions through two well characterized receptor systems, the CB1 and CB2 receptors. Work by a number of groups in recent years has provided evidence that the system is more complicated and additional receptor types should exist to explain ligand activity in a number of physiological processes.

EXPERIMENTAL APPROACH

Cells transfected with the human cDNA for GPR55 were tested for their ability to bind and to mediate GTPgammaS binding by cannabinoid ligands. Using an antibody and peptide blocking approach, the nature of the G-protein coupling was determined and further demonstrated by measuring activity of downstream signalling pathways.

KEY RESULTS

We demonstrate that GPR55 binds to and is activated by the cannabinoid ligand CP55940. In addition endocannabinoids including anandamide and virodhamine activate GTPgammaS binding via GPR55 with nM potencies. Ligands such as cannabidiol and abnormal cannabidiol which exhibit no CB1 or CB2 activity and are believed to function at a novel cannabinoid receptor, also showed activity at GPR55. GPR55 couples to Galpha13 and can mediate activation of rhoA, cdc42 and rac1.

CONCLUSIONS

These data suggest that GPR55 is a novel cannabinoid receptor, and its ligand profile with respect to CB1 and CB2 described here will permit delineation of its physiological function(s).

Germline E-cadherin mutations in familial lobular breast cancer

BACKGROUND

The cell surface glycoprotein E-cadherin (CDH1) is a key regulator of adhesive properties in epithelial cells. Germline mutations in CDH1 are well established as the defects underlying hereditary diffuse gastric cancer (HDGC) syndrome, and an increased risk of lobular breast cancer (LBC) has been described in HDGC kindreds. However, germline CDH1 mutations have not been described in patients with LBC in non-HDGC families. This study aimed to investigate the frequency of germline CDH1 mutations in patients with LBC with early onset disease or family histories of breast cancer without DGC.

METHODS

Germline DNA was analysed in 23 women with invasive lobular or mixed ductal and lobular breast cancers who had at least one close relative with breast cancer or had themselves been diagnosed before the age of 45 years, had tested negative for a germline BRCA1 or BRCA2 mutation, and reported no personal or family history of diffuse gastric cancer. The full coding sequence of CDH1 including splice junctions was amplified using PCR and screened for mutations using DHPLC and sequencing.

RESULTS

A novel germline CDH1 truncating mutation in the extracellular portion of the protein (517insA) was identified in one woman who had LBC at the age of 42 years and a first degree relative with invasive LBC.

CONCLUSIONS

Germline CDH1 mutations can be associated with invasive LBC in the absence of diffuse gastric cancer. The finding, if confirmed, may have implications for management of individuals at risk for this breast cancer subtype. Clarification of the cancer risks in the syndrome is essential.

Adenosine is not a direct GHSR agonist--artificial cross-talk between GHSR and adenosine receptor pathways

AIM

To assess if adenosine is a direct growth hormone secretagogue receptor (GHSR) agonist by investigating the mechanism behind adenosine induced calcium release in human embryonic kidney 293s (HEK) cells expressing GHSR.

METHODS

Calcium mobilization, cyclic adenosine monophosphate (cAMP) and IP(3) experiments were performed using HEK cells stably expressing GHSR and/or adenosine A(2B) receptor (A(2B)R).

RESULTS

Adenosine has been widely reported as a GHSR agonist. In our hands, adenosine and forskolin stimulated calcium release from IP(3) controlled stores in HEK-GHSR cells but not in non-transfected HEK cells. This release was not accompanied by increased IP(3) levels. The calcium release was both cholera toxin and U73122 sensitive, indicating the involvement of both Galpha(s)/adenylyl cyclase and Galpha(q/11)/phospholipase C pathways. Importantly, the GHSR inverse agonist [D-Arg(1) D-Phe(5) D-Trp(7,9) Leu(11)]-Substance P (SP-analogue) blocked the adenosine stimulated calcium release, demonstrating that GHSR is involved. Assessment of the GHSR-dependent calcium release using adenosine receptor agonists and antagonists resulted in a rank order of potencies resembling the profile of A(2B)R. A(2B)R over-expression in HEK-GHSR cells enhanced potency and efficacy of the adenosine induced calcium release without increasing IP(3) production. Moreover, A(2B)R over-expression in HEK cells potentiated NECA-induced cAMP production. However, GHSR expression had no effect on intracellular cAMP production.

CONCLUSION

In HEK-GHSR cells adenosine activates endogenously expressed A(2B)R resulting in calcium mobilization. We hypothesize that the responsible mechanism is cAMP-dependent sensitization of IP(3) receptors for the high basal level of IP(3) caused by GHSR constitutive activity. Altogether, our results demonstrate that adenosine is not a direct GHSR agonist.

Proliferation of primitive myeloid progenitors can be reversibly induced by HOXA10

Recent studies show that several Hox transcription factors are important for regulation of proliferation and differentiation in hematopoiesis. Among these is H0XA10, which is selectively expressed at high levels in the most primitive subpopulation of human CD34(+) bone marrow cells. When overexpressed, H0XA10 increases the proliferation of early progenitor cells and can lead to the development of myeloid leukemia. To study the effects of H0XA10 on primitive hematopoietic progenitors in more detail, transgenic mice were generated with regulatable H0XA10 expression. The transgenic mouse model, referred to as tetO-HOXA10, contains the H0XA10 gene controlled by a tetracycline-responsive element and a minimal promoter. Thus, the expression of H0XA10 is inducible and reversible depending on the absence or presence of tetracycline or its analog, doxycycline. A retroviral vector containing the tetracycline transactivator gene (tTA) was used to induce expression of the H0XA10 gene in bone marrow cells from the transgenic mice. Reverse transcription-polymerase chain reaction analysis confirmed regulatable H0XA10 expression in several transgenic lines. H0XA10 induction led to the formation of hematopoietic colonies containing blastlike cells and megakaryocytes. Moreover, the induction of H0XA10 resulted in significant proliferative advantage of primitive hematopoietic progenitors (spleen colony-forming units [CFU-S(12)]), which was reversible on withdrawal of induction. Activation of H0XA10 expression in tet0-H0XA10 mice will therefore govern proliferation of primitive myeloid progenitors in a regulated fashion. This novel animal model can be used to identify the target genes of HOXA10 and better clarify the specific role of HOXA10 in normal and malignant hematopoiesis.

Liquid chromatographic determination of total and beta-N-oxalyl-L-alpha,beta-diaminopropionic acid in lathyrus sativus seeds using both refractive index and bioelectrochemical detection

A further improved chromatographic method for the simultaneous determination of the total amount of ODAP, selectively the amount of its neurotoxic form, beta-ODAP, and free L-glutamate in raw Lathyrus sativus (grass pea) seed samples is described using post-column refractive index in combination with bioelectrochemical detection. The biosensor is based on crosslinking horseradish peroxidase (HRP) and an Os-containing mediating polymer with poly(ethyleneglycol)(400) diglycidyl ether (PEGDGE), forming an inner hydrogel layer and then immobilising L-glutamate oxidase (GlOx) as an outer layer on top of a graphite electrode. Addition of polyethylenimine (PEI) to the hydrogel is believed to have sensitivity and stability enhancing effect on the biosensor. The double-layer approach in the biosensor construction avoided direct electrical wiring of GlOx and resulted in a higher sensitivity of 4.6 mA/M cm2 with respect to beta-ODAP and a wider linear range (1-250 microM) for both L-glutamate and beta-ODAP when compared with a single-layer approach where GlOx, HRP, and Os-polymer are crosslinked together. The limit of detection for the chromatographic-biosensor system was found to be 2 microM with respect to beta-ODAP and 0.7 microM with respect to L-glutamate. The refractive index detection on-line with the biosensor enabled full control of the chromatographic system for the determination of the total amount of ODAP, selectively the amount of beta-ODAP and L-glutamate. Ten grass pea samples have been collected from Lathyrism prone areas of Ethiopia to test the applicability of the presently developed analytical system for real sample analysis. The toxin levels of grass pea collections were determined in an aqueous extracts and ranged from 0.52 to 0.76%, dry mass basis. Comparison of results of an established spectrophotometric assay and that of the present system has shown an extraordinary degree of agreement as revealed by parallel "t" test (90% confidence limit). The present system has operational stability of more than 50 h. Analysis time per sample is 10 min after extraction for 90 min.

The catastrophe-promoting activity of ectopic Op18/stathmin is required for disruption of mitotic spindles but not interphase microtubules

Oncoprotein18/stathmin (Op18) is a microtubule (MT) destabilizing protein that is inactivated during mitosis by phosphorylation at four Ser-residues. Op18 has at least two functions; the N-terminal region is required for catastrophe-promotion (i.e., transition from elongation to shortening), while the C-terminal region is required to inhibit MT-polymerization rate in vitro. We show here that a "pseudophosphorylation" derivative of Op18 (i.e., four Ser- to Glu-substitutions at phosphorylation sites) exhibits a selective loss of catastrophe-promoting activity. This is contrasted to authentic phosphorylation, which efficiently attenuates all activities except tubulin binding. In intact cells, overexpression of pseudophosphorylated Op18, which is not phosphorylated by endogenous kinases, is shown to destabilize interphase MTs but to leave spindle formation untouched. To test if the mitotic spindle is sensitive only to the catastrophe-promoting activity of Op18 and resistant to C-terminally associated activities, N- and C-terminal truncations with defined activity-profiles were employed. The cell-cycle phenotypes of nonphosphorylatable mutants (i.e., four Ser- to Ala-substitutions) of these truncation derivatives demonstrated that catastrophe promotion is required for interference with the mitotic spindle, while the C-terminally associated activities are sufficient to destabilize interphase MTs. These results demonstrate that specific Op18 derivatives with defined activity-profiles can be used as probes to distinguish interphase and mitotic MTs.

Mutational analysis of op18/stathmin-tubulin-interacting surfaces. Binding cooperativity controls tubulin GTP hydrolysis in the ternary complex

Oncoprotein 18 (Op18) is a microtubule regulator that forms a ternary complex with two tubulin heterodimers. Dispersed regions of Op18 are involved in two-site cooperative binding and subsequent modulation of tubulin GTPase activity. Here we have analyzed specific determinants of Op18 that govern both stoichiometry and positive cooperativity in tubulin binding and consequent stimulatory and inhibitory effects on tubulin GTPase activity. The data revealed that the central and C-terminal regions of Op18 contain overlapping binding-motifs contacting both tubulin heterodimers, suggesting that these regions of Op18 are wedged into the previously noted 1-nm gap between the two longitudinally arranged tubulin heterodimers. Both the N- and C-terminal flanks adjacent to the central region are involved in stabilizing the ternary complex, but only the C-terminal flank does so by imposing positive binding cooperativity. Within the C-terminal flank, deletion of a 7-amino acid region attenuated positive binding cooperativity and resulted in a switch from stimulation to inhibition of tubulin GTP hydrolysis. This switch can be explained by attenuated binding cooperativity, because Op18 under these conditions may block longitudinal contact surfaces of single tubulins with consequent interference of tubulin-tubulin interaction-dependent GTP hydrolysis. Together, our results suggest that Op18 links two tubulin heterodimers via longitudinal contact surfaces to form a ternary GTPase productive complex.

User charges for antenatal care and ultrasound--an unwillingness to pay

OBJECTIVE

The aim of this study was to evaluate attitudes towards user charges in specialized antenatal care, as well as if ultrasound for dating and antenatal care provided by a midwife or family doctor had been charged.

SUBJECTS AND METHODS

Participants included all women delivering and registered for antenatal care at the Umeå University Hospital from September 15th-December 20th, 1995. Questionnaires, used to measure attitudes towards specialist fees, and the influence these user charges have on the utilization of services, were mailed two weeks post partum.

RESULTS

Few mothers, 4%, actually hesitated or refrained from charged care, while 19%-50% would have hesitated or refrained from care if being charged. Bad economy was the significant risk factor for unwillingness to pay for care by midwife OR 2.7 (95% CI 1.4-5.6) and family doctor OR 2.5 (95% CI 1.3-5.0), referral charged for specialist care OR 4.2 (95% CI 0.5-38) and if charged early ultrasound OR 4.6 (95% CI 2.4-9.2). When adjusted for economy neither young maternal age, father's unemployment or low birth weight were significantly associated to a unwillingness to pay.

CONCLUSIONS

The attitudes expressed implied that user charges could lower attendance of pregnancy ultrasound and antenatal care. This could add a substantial negative impact on perinatal outcome to an already affected group of infants with an increased risk of a low birth weight and preterm delivery, and interfere with the benefits of early dating by ultrasound.

Mutations of oncoprotein 18/stathmin identify tubulin-directed regulatory activities distinct from tubulin association

Oncoprotein 18/stathmin (Op18) is a recently identified phosphorylation-responsive regulator of the microtubule (MT) system. It was originally proposed that Op18 specifically regulates dynamic properties of MTs by associating with tubulin, but it has subsequently been proposed that Op18 acts simply by sequestering of tubulin heterodimers. We have dissected the mechanistic action of Op18 by generation of two distinct classes of mutants. One class has interruptions of the heptad repeats of a potential coiled-coil region of Op18, and the other involves substitution at all four phosphorylation sites with negatively charged Glu residues. Both types of mutation result in Op18 proteins with a limited decrease in tubulin complex formation. However, the MT-destabilizing activities of the coiled-coil mutants are more severely reduced in transfected leukemia cells than those of the Glu-substituted Op18 derivative, providing evidence for tubulin-directed regulatory activities distinct from tubulin complex formation. Analysis of Op18-mediated regulation of tubulin GTPase activity and taxol-promoted tubulin polymerization showed that while wild-type and Glu-substituted Op18 derivatives are active, the coiled-coil mutants are essentially inactive. This suggests that Op18-tubulin contact involves structural motifs that deliver a signal of regulatory importance to the MT system.

Dissociation of the tubulin-sequestering and microtubule catastrophe-promoting activities of oncoprotein 18/stathmin

Oncoprotein 18/stathmin (Op18) has been identified recently as a protein that destabilizes microtubules, but the mechanism of destabilization is currently controversial. Based on in vitro microtubule assembly assays, evidence has been presented supporting conflicting destabilization models of either tubulin sequestration or promotion of microtubule catastrophes. We found that Op18 can destabilize microtubules by both of these mechanisms and that these activities can be dissociated by changing pH. At pH 6.8, Op18 slowed microtubule elongation and increased catastrophes at both plus and minus ends, consistent with a tubulin-sequestering activity. In contrast, at pH 7.5, Op18 promoted microtubule catastrophes, particularly at plus ends, with little effect on elongation rates at either microtubule end. Dissociation of tubulin-sequestering and catastrophe-promoting activities of Op18 was further demonstrated by analysis of truncated Op18 derivatives. Lack of a C-terminal region of Op18 (aa 100-147) resulted in a truncated protein that lost sequestering activity at pH 6.8 but retained catastrophe-promoting activity. In contrast, lack of an N-terminal region of Op18 (aa 5-25) resulted in a truncated protein that still sequestered tubulin at pH 6.8 but was unable to promote catastrophes at pH 7.5. At pH 6. 8, both the full length and the N-terminal-truncated Op18 bound tubulin, whereas truncation at the C-terminus resulted in a pronounced decrease in tubulin binding. Based on these results, and a previous study documenting a pH-dependent change in binding affinity between Op18 and tubulin, it is likely that tubulin sequestering observed at lower pH resulted from the relatively tight interaction between Op18 and tubulin and that this tight binding requires the C-terminus of Op18; however, under conditions in which Op18 binds weakly to tubulin (pH 7.5), Op18 stimulated catastrophes without altering tubulin subunit association or dissociation rates, and Op18 did not depolymerize microtubules capped with guanylyl (alpha, beta)-methylene diphosphonate-tubulin subunits. We hypothesize that weak binding between Op18 and tubulin results in free Op18, which is available to interact with microtubule ends and thereby promote catastrophes by a mechanism that likely involves GTP hydrolysis.

Regulation of microtubule dynamics by extracellular signals: cAMP-dependent protein kinase switches off the activity of oncoprotein 18 in intact cells

Oncoprotein 18 (Op18, also termed p19, 19K, metablastin, stathmin, and prosolin) is a recently identified regulator of microtubule (MT) dynamics. Op18 is a target for both cell cycle and cell surface receptor-coupled kinase systems, and phosphorylation of Op18 on specific combinations of sites has been shown to switch off its MT-destabilizing activity. Here we show that induced expression of the catalytic subunit of cAMP-dependent protein kinase (PKA) results in a dramatic increase in cellular MT polymer content concomitant with phosphorylation and partial degradation of Op18. That PKA may regulate the MT system by downregulation of Op18 activity was evaluated by a genetic system allowing conditional co-expression of PKA and a series of kinase target site-deficient mutants of Op18. The results show that phosphorylation of Op18 on two specific sites, Ser-16 and Ser-63, is necessary and sufficient for PKA to switch off Op18 activity in intact cells. The regulatory importance of dual phosphorylation on Ser-16 and Ser-63 of Op18 was reproduced by in vitro assays. These results suggest a simple model where PKA phosphorylation downregulates the MT-destabilizing activity of Op18, which in turn promotes increased tubulin polymerization. Hence, the present study shows that Op18 has the potential to regulate the MT system in response to external signals such as cAMP-linked agonists.

Early dating by ultrasound and perinatal outcome. A cohort study

BACKGROUND

This study aims to evaluate the impact of routine ultrasound in early pregnancy on pregnancy outcome and perinatal mortality.

METHODS

Using the Swedish Medical Birth Registry, a two-stage study was designed. First, an ecological study that included data from 45 hospitals, with 1,280,746 children born during the years 1974-1991, was designed by differentiating hospitals on the basis of ultrasound usage. Second, a historical cohort study (n = 60,864) was designed for the years 1982-84, including a treatment group (having had routine ultrasound in early pregnancy) and a reference group (having had no routine ultrasound).

RESULTS

In hospitals practicing early dating by ultrasound, post-term births were reduced from 13.3% to 7.4%, while pre-term births were increased from 5.7% to 6.8%. For the treatment group, the cohort study showed: 1) fewer post-term births, RR 0.7 (95% CL 0.7-0.8), 2) lower post-term perinatal mortality, RR 0.3 (95% CL 0.1-1.0), 3) fewer twin births post-term, RR 0.1 (95% CL 0.1-0.7), 4) fewer acute growth retarded among term, RR 0.7 (95% CL 0.6-0.9) and post-term, RR 0.3 (95% CL 0.1-1.1), and 5) a tendency towards less asphyxia among post-term births.

CONCLUSION

The study shows that early dating with ultrasound increases the possibilities of clinical judgment at the end of the pregnancy and also indicates that the procedure could contribute to a positive perinatal outcome.

Control of microtubule dynamics by oncoprotein 18: dissection of the regulatory role of multisite phosphorylation during mitosis

Oncoprotein 18 (Op18; also termed p19, 19K, metablastin, stathmin, and prosolin) is a conserved protein that regulates microtubule (MT) dynamics. Op18 is multisite phosphorylated on four Ser residues during mitosis; two of these Ser residues, Ser-25 and Ser-38, are targets for cyclin-dependent protein kinases (CDKs), and the other two Ser residues, Ser-16 and Ser-63, are targets for an unidentified protein kinase. Mutations of the two CDK sites have recently been shown to result in a mitotic block caused by destabilization of MTs. To understand the role of Op18 in regulation of MT dynamics during mitosis, in this study we dissected the functions of all four phosphorylation sites of Op18 by combining genetic, morphological, and biochemical analyses. The data show that all four phosphorylation sites are involved in switching off Op18 activity during mitosis, an event that appears to be essential for formation of the spindle during metaphase. However, the mechanisms by which specific sites down-regulate Op18 activity differ. Hence, dual phosphorylation on the CDK sites Ser-25 and Ser-38 appears to be required for phosphorylation of Ser-16 and Ser-63; however, by themselves, the CDK sites are of only minor importance in direct regulation of Op18 activity. Subsequent phosphorylation of either Ser-16, Ser-63, or both efficiently switches off Op18 activity.

Regulation of microtubule dynamics by Ca2+/calmodulin-dependent kinase IV/Gr-dependent phosphorylation of oncoprotein 18

Oncoprotein 18 (Op18; also termed p19, 19K, p18, prosolin, and stathmin) is a regulator of microtubule (MT) dynamics and is phosphorylated by multiple kinase systems on four Ser residues. In addition to cell cycle-regulated phosphorylation, external signals induce phosphorylation of Op18 on Ser-25 by the mitogen-activated protein kinase and on Ser-16 by the Ca2+/calmodulin-dependent kinase IV/Gr (CaMK IV/Gr). Here we show that induced expression of a constitutively active mutant of CaMK IV/Gr results in phosphorylation of Op18 on Ser-16. In parallel, we also observed partial degradation of Op18 and a rapid increase of total cellular MTs. These results suggest a link between CaMK IV/Gr, Op18, and MT dynamics. To explore such a putative link, we optimized a genetic system that allowed conditional coexpression of a series of CaMK IV/Gr and Op18 derivatives. The result shows that CaMK IV/Gr can suppress the MT-regulating activity of Op18 by phosphorylation on Ser-16. In line with these results, by employing a chemical cross-linking protocol, it was shown that phosphorylation of Ser-16 is involved in weakening of the interactions between Op18 and tubulin. Taken together, these data suggest that the mechanism of CaMK IV/Gr-mediated suppression of Op18 activity involves both partial degradation of Op18 and direct modulation of the MT-destabilizing activity of this protein. These results show that Op18 phosphorylation by CaMK IV/Gr may couple alterations of MT dynamics in response to external signals that involve Ca2+.

Oncoprotein 18 is a phosphorylation-responsive regulator of microtubule dynamics

Oncoprotein 18 (Op18, also termed p19, p18, prosolin or stathmin) is a cytosolic protein of previously unknown function. Phosphorylation of Op18 is cell cycle regulated by cyclin-dependent kinases (CDKs), and expression of a 'CDK target site-deficient mutant' results in a phenotype indicative of a role for Op18 during mitosis. This phenotype is compatible with the idea that Op18 is a phosphorylation-responsive regulator of microtubule (MT) dynamics. Therefore, in this study, we analyzed MTs in cells induced to express either wild-type or mutated Op18. The results showed that wild-type Op18 and a CDK target site mutant both efficiently elicited rapid depolymerization of MTs. This result contrasts with clear-cut differences in their cell cycle phenotypes. Morphological analysis of MTs explained this apparent discrepancy: while interphase MTs were depolymerized in cells expressing either Op18 derivative, apparently normal mitotic spindles were formed only in cells overexpressing wild-type Op18. This result correlates with our finding that only mutated Op18 causes a block during mitosis. Hence, we conclude that Op18 decreases MT stability and that this activity of Op18 is subject to cell cycle regulation by CDKs.

G2/M transition requires multisite phosphorylation of oncoprotein 18 by two distinct protein kinase systems

Oncoprotein 18 (Op18) is a conserved cytosolic protein that is a target for both cell cycle and cell surface receptor-regulated phosphorylation events. The four residues Ser16, Ser25, Ser38, and Ser63 are all subject to cell cycle-regulated phosphorylation. Ser25 and Ser38 are targets for cyclin dependent kinases (CDKs), while Ser16 and Ser63 are phosphorylated by an unidentified protein kinase. We have recently shown that induced expression of a CDK target site-deficient mutant, Op18-S25A,S38A, blocks human cell lines during G2/M transition. In the present report we show that mitosis is associated with complete phosphorylation of the two Op18 CDK target sites Ser25 and Ser38 and that Ser16 and Ser63 are also phosphorylated to a high stoichiometry. To evaluate the function of multisite phosphorylation of Op18, we expressed and analyzed the cell cycle phenotype of different kinase target site-deficient mutants. The data showed that induced expression of the S16A,S63A, S25A,S38A, and S16A,S25A,S38A,S63A mutants all resulted in an indistinguishable phenotype, i.e. immediate G2/M block and subsequent endoreduplication, a given fraction of G2 versus M-phase blocked cells, and a characteristic nuclear morphology of M-blocked cells. This result was unexpected; however, a likely explanation was provided by analysis of Op18 phosphoisomers, which revealed that mutations of the CDK sites interfere with phosphorylation of Ser16 and Ser63. The simplest interpretation of our results is that phosphorylation of Ser16 and Ser63 is essential during G2/M transition and that the phenotype of the S25A,S38A mutant is mediated by the observed block of Ser16/Ser63 phosphorylation.

Serine 16 of oncoprotein 18 is a major cytosolic target for the Ca2+/calmodulin-dependent kinase-Gr

Oncoprotein 18 (Op18) is a cytosolic protein that was initially identified due to its up-regulated expression in acute leukemia and its complex pattern of phosphorylation in response to diverse extracellular signals. We have previously identified in vivo phosphorylation sites and some of the protein kinase systems involved. Two distinct proline-directed kinase families phosphorylate Ser25 and Ser38 of Op18 with overlapping but distinct site preference. These two kinase families, mitogen-activated protein (MAP) kinases and cyclin-dependent cdc2 kinases, are involved in receptor-regulated and cell-cycle-regulated phosphorylation events, respectively. During analysis of Op18 phosphorylation in the Jurkat T-cell line, we also found that Ser16 of Op18 is phosphorylated in response to a Ca2+ signal generated by T-cell receptor stimulation or the Ca2+ ionophore ionomycin. As suggested by a previous study, T-cell-receptor-induced phosphorylation events may be mediated by the Ca2+/CaM-dependent protein kinase type Gr (CaM kinase-Gr). The present study shows that activation of this protein kinase correlates with phosphorylation of Ser16 of Op18, and in vitro experiments reveal efficient and selective phosphorylation of this residue. The CaM kinase-Gr is only expressed in certain lymphoid cell lines, and the present study shows that ionomycin-induced phosphorylation of Op18 Ser16 is restricted to cells expressing this protein kinase. Finally, CaM kinase-Gr-dependent in vitro phosphorylation of a crude cellular extract reveals a striking preference of this protein kinase for Op18 compared to other cellular substrates. In conclusion, the results suggest that Ser16 of Op18 is a major cytosolic target for activated CaM kinase-Gr.

Penetration forces in cannulation of the dorsal veins of the hand: I. A comparison between polyurethane (Insyte) and polytetrafluoroethylene (Venflon) cannulae. Results of a study in volunteers compared with those from an in vitro study

The functional tip tapering design of peripheral venous cannulae (introducer steel needle + catheter) made of polyurethane (PUR-Instye) and polytetrafluoroethylene (PTFE-Venflon) was studied with 3 techniques: A) Scanning electron microscopy (SEM). B) Measurement of penetration forces in vitro through latex membranes and lamb skins with a tensile-compression apparatus (Instron-1122) at 1) the introducer steel-needle point, 2) the needle heel (the spot marking the passage from the point of the needle to its shaft). 3) the catheter top (i.e. the beginning of the plastic sheath), 4) the catheter tip, i.e. the beginning of the largest diameter of the plastic sheath, and 5) between the catheter tip and its hub (catheter friction). C) Two cannulae (one of each type for every subject were inserted at random into the dorsal veins of the left and right hand in 37 volunteers, and the penetration forces were measured with a force transducer.

RESULTS

A) The PUR-cannulae had a lancet-like appearance and a smoother transition at the catheter top, whilst the PTFE cannulae were arrow-like, cut back and had a less accentuated conical design. B) Penetration forces in vitro through latex membranes were 9-41 times lower (P less than 0.0001) than those through the large skins. The highest forces (mean +/- s.d.) registered in vitro (lamb skins) were 4.1 +/- 0.2 Newtons (N) with PUR-cannulae at the catheter tip, and 3.4 +/- 0.6 with the PTFE-cannulae at the catheter top (P less than 0.05). C).(ABSTRACT TRUNCATED AT 250 WORDS)

Disturbances of blood-flow velocity in the dorsal veins of the hand after vein cannulation and cannula fixation in the anaesthetised patient

Modifications of the mean blood-flow velocity in the dorsal veins of the hand were assessed semi-quantitatively with continuous wave (CW) Doppler equipment in 32 anaesthetised patients (17 men and 15 women), 23-78 (median = 56) years of age, before and after venous catheterisation with cannula fixation to the skin. Cannulation of the vein caused a 48% reduction in the mean blood-flow velocity and made it impossible to detect any flow with the equipment used in 22% of the patients. A 10% further reduction in the mean blood-flow velocity and in the number of subjects with undetectable blood flow was observed after fixation of the cannulae. Age, small vein diameter, and hyperventilation (end-tidal carbon dioxide less than or equal to 3.5 volume % appeared to be significant factors reducing blood-flow velocities in the cannulated veins. It is concluded that venous catheterisation and fixation of the cannula induce a significant reduction in the blood-flow velocity.

Cannula thrombophlebitis: a study in volunteers comparing polytetrafluoroethylene, polyurethane, and polyamide-ether-elastomer cannulae

Cannulae made of polytetrafluoroethylene (PTFE: n = 11), thermoplastic polyether-urethane (TPEU: n = 11), and a new test material, polyamide-ether-elastomer (XLON: n = 10) were inserted into the veins of the dorsum of the hand in 32 healthy volunteers (10 women and 22 men), 21-50 years old. The cannulae were intended to be left in place for 5 days. No infusion was given and the dressings were not exchanged. The resulting thrombophlebitis, defined as two or more of the symptoms pain, redness, oedema and hardness, was estimated on a scale which took into account the incidence, location, intensity, and duration of the symptoms. Except for one volunteer in the XLON group, all the volunteers developed thrombophlebitis, generally observed on the third day of cannulation, and being more frequent and intense over the cannulae (P less than 0.001) and at the tip (P less than 0.01) than at the insertion sites. Pain and oedema were, on the whole, the most frequent and severe symptoms during the period of indwelling. After withdrawal, hardness was the most intense, and together with pain, the most long-lasting (up to 10 days) symptom. The differences between the materials in thrombophlebitis incidence and intensity were statistically significant only when each symptom was analysed separately. Thus, the PTFE cannulae caused more pain and hardness (probably because of greater platelet adhesion and a relatively greater stiffness), while the TPEU and XLON cannulae produced more periphlebitis (redness and oedema), probably because of potentially irritant and antigenic substances leaking from them (polyurethane oligomers and polyamide/polyethyleneglycol oligomers).

High-performance liquid chromatographic separation and extraction investigation for the simultaneous determination of mefloquine and its carboxylic acid metabolite

Distribution ratios of mefloquine ion pairs with perchlorate and heptanesulphonate as counter-ions, the base distribution for mefloquine, the acid distribution for the carboxylic acid metabolite and the ion-pair distribution with quaternary ammonium ions as counter ions have been determined. Differences in retention characteristics with several commercially available supports bearing the same octadecyl label were found. The effect on the retention time of the pH, the percentage acetonitrile and the addition of an amine to the mobile phase were studied. Other antimalarial drugs present concurrently in the sample showed no chromatographic interference with mefloquine and its metabolite. A suitable internal standard for use in the analytical method was also tested.