Vaginal bacterial load in the second trimester is associated with early preterm birth recurrence: a nested case-control study.

OBJECTIVE: To assess the association between vaginal microbiome (VMB) composition and recurrent early spontaneous preterm birth (sPTB)/preterm prelabour rupture of membranes (PPROM). DESIGN: Nested case-control study. SETTING: UK tertiary referral hospital. SAMPLE: High-risk women with previous sPTB/PPROM <34+0 weeks' gestation who had a recurrence (n = 22) or delivered at ≥37+0 weeks without PPROM (n = 87). METHODS: Vaginal swabs collected between 15 and 22 weeks' gestation were analysed by 16S rRNA gene sequencing and 16S quantitative PCR. MAIN OUTCOME MEASURE: Recurrent early sPTB/PPROM. RESULTS: Of the 109 high-risk women, 28 had anaerobic vaginal dysbiosis, with the remainder dominated by lactobacilli (Lactobacillus iners 36/109, Lactobacillus crispatus 23/109, or other 22/109). VMB type and diversity were not associated with recurrence. Women with a recurrence, compared to those without, had a higher median vaginal bacterial load (8.64 versus 7.89 log10 cells/mcl, adjusted odds ratio [aOR] 1.90, 95% CI 1.01-3.56, P = 0.047) and estimated Lactobacillus concentration (8.59 versus 7.48 log10 cells/mcl, aOR 2.35, (95% CI 1.20-4.61, P = 0.013). A higher recurrence risk was associated with higher median bacterial loads for each VMB type after stratification, although statistical significance was reached only for L. iners domination (aOR 3.44, 95% CI 1.06-11.15, P = 0.040). Women with anaerobic dysbiosis or L. iners domination had a higher median vaginal bacterial load than women with a VMB dominated by L. crispatus or other lactobacilli (8.54, 7.96, 7.63, and 7.53 log10 cells/mcl, respectively). CONCLUSIONS: Vaginal bacterial load is associated with early sPTB/PPROM recurrence. Domination by lactobacilli other than L. iners may protect women from developing high bacterial loads. Future PTB studies should quantify vaginal bacteria and yeasts. TWEETABLE ABSTRACT: Increased vaginal bacterial load in the second trimester may be associated with recurrent early spontaneous preterm birth.

Accuracy of the combination of commercially available biomarkers and cervical length measurement to predict preterm birth in symptomatic women: A systematic review.

An accurate prognostic method for preterm birth (PTB) could avoid unnecessary treatment(s) with potentially negative effects. The objective was to explore the prognostic accuracy of commercially available bedside cervicovaginal biomarker tests in combination with cervical length (CL) compared to CL measurement alone and/or a biomarker test alone, for PTB within 7 days after testing symptomatic women at 22-34 weeks. The MEDLINE, Cochrane, Embase and Web of Science databases were searched from inception to August 28th, 2019. Seven hundred and eight articles were identified and screened using Rayyan. Studies reporting on the predictive accuracy of combined tests compared to CL or biomarker alone for the prediction of PTB within 7 days of testing in symptomatic women with intact membranes were included. A piloted data extraction form was used. Direct comparisons of the prognostic accuracy of the combination test with CL measurement or a biomarker alone were done, as well as comparisons of prognostic accuracy of the included combination tests (indirect comparisons). Twelve articles were included (seven on fetal fibronectin, four on phosphorylated insulin-like growth factor binding protein-1, one comparing both). A variety of CL cut-offs was reported. The results could not demonstrate superiority of a combination method compared to single methods. Due to data scarcity and quality, the superiority of either predictive test for PTB, either combination or single, cannot be demonstrated with this systematic review. We recommend further research to compare available biomarkers.

Cervical cerclage, pessary, or vaginal progesterone in high-risk pregnant women with short cervix: a randomized feasibility study.

Objective: To assess feasibility for a definitive randomized controlled trial (RCT) comparing three treatments for short cervix in a population at high risk for spontaneous preterm birth (sPTB) over a 1-year period.Design: Three arm, open label feasibility randomized clinical study.Methods: Women with singleton pregnancy with risk factors for sPTB (history of sPTB or prelabor premature rupture of membranes (PPROM) <34 weeks or significant cervical surgery), and short cervix on transvaginal ultrasound scan detected between 16+0 and 24+6 weeks gestation were randomized to receive either cervical cerclage, vaginal pessary, or vaginal progesterone 200 mg nocte. Pregnancy outcomes and treatment costs were collected from hospital records, NHS Reference costs, and British National Formulary costs.Main outcome measures: Feasibility targets were defined as (i) at least 55% of eligible women randomized; (ii) maximum 5% failure to adhere to the protocol per arm; (iii) maximum 5% loss to short-term follow-up.Results: Of 417 women screened between October 2015 and 2016, 25 (6%) were eligible for trial inclusion, of whom 18 (72%) agreed to participate at the rate 0.75 participants/site/month. Adherence to protocol was 100% in pessary and cerclage arms and 80% in vaginal progesterone arm (95% CI 24-100%). No participants were lost to follow up. Cost of interventions accounted for 6% (95% CI 2-10%) of overall health care expenditure.Conclusions: A definitive clinical trial comparing treatments for prevention of sPTB in high-risk women with short cervix is feasible but will be challenging due to small numbers of eligible participants.

Effect of QUiPP prediction algorithm on treatment decisions in women with a previous preterm birth: a prospective cohort study.

OBJECTIVE: The QUiPP algorithm combines cervical length, quantitative fetal fibronectin (qfFN) and medical history to quantify risk of preterm birth. We assessed the utility of QUiPP to inform preterm birth prevention treatment decisions. DESIGN: A prospective cohort study with a subsequent impact assessment using the QUiPP risk of birth before 34 weeks' gestation. SETTING: A UK tertiary referral hospital. SAMPLE: In all, 119 women with previous spontaneous preterm birth (sPTB) or preterm premature rupture of membranes (PPROM) before 34 weeks' gestation. METHODS: Cervical length and qfFN were measured at 19+0 to 23+0  weeks' gestation. Clinical management was based on history and cervical length. After birth, clinicians were unblinded to qfFN results and QUiPP analysis was undertaken. MAIN OUTCOME MEASURES: Predictive statistics of QUiPP algorithm using 10% risk of sPTB before 34+0  weeks as treatment threshold. RESULTS: Fifteen of 119 women (13%) had PPROM or sPTB before 34 weeks. Of these, 53% (8/15) had QUiPP risk of sPTB before 34+0  weeks above 10%. Applying this treatment threshold in practice would have doubled our treatment rate (20 versus 42%). QUIPP threshold of 10% had positive likelihood ratio (LR) of 1.3 (95% CI 0.76-2.18), and negative LR of 0.8 (95% CI 0.45-1.40) for predicting sPTB before 34+0  weeks. CONCLUSIONS: Use of the QUiPP algorithm in this population may lead to substantial increase in interventions without evidence that currently available treatment options are beneficial for this particular group. TWEETABLE ABSTRACT: Independent study finds that the QUiPP algorithm could lead to substantial increases in treatment without evidence of benefit.

Should phenotype of previous preterm birth influence management of women with short cervix in subsequent pregnancy? Comparison of vaginal progesterone and Arabin pessary.

OBJECTIVE: To investigate whether the classification of a previous spontaneous preterm birth (sPTB) as preterm labor (PTL) with intact membranes (IM) or as preterm prelabor rupture of membranes (PPROM) impacts the efficacy of cervical pessary or vaginal progesterone for prevention of sPTB in pregnant women with short cervix on transvaginal ultrasound. METHODS: This was a retrospective cohort study of asymptomatic high-risk singleton pregnancies with a short cervix and history of sPTB, treated using Arabin pessary or vaginal progesterone for primary PTB prevention, conducted at four European hospitals. A log-rank test on Kaplan-Meier curves was used to assess the difference in performance of pessary and progesterone, according to history of PTL-IM or PPROM. Linear regression analysis was used to evaluate significant predictors of gestational age at delivery. RESULTS: Between 2008 and 2015, 170 women were treated with a pessary and 88 with vaginal progesterone. In women treated with a pessary, rate of sPTB < 34 weeks was 16% in those with a history of PTL-IM and 55% in those with a history of PPROM. In women treated with progesterone, rate of sPTB < 34 weeks was 13% in those with a history of PTL-IM and 21% in those with a history of PPROM. Treatment with a pessary resulted in earlier delivery in women with previous PPROM than in any other subgroup (P < 0.0001). Linear regression analysis showed a clear effect of PPROM history (P < 0.0001), combination of PPROM history and treatment (P = 0.0003) and cervical length (P = 0.0004) on gestational age at birth. CONCLUSIONS: Cervical pessary may be a less efficacious treatment option for women with previous PPROM; however, these results require prospective validation before change in practice is recommended. Phenotype of previous preterm birth may be an important risk predictor and treatment effect modifier; this information should be reported in future clinical trials. © 2018 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of the International Society of Ultrasound in Obstetrics and Gynecology.

The influence of the introduction of national guidelines on preterm birth prevention practice: UK experience.

OBJECTIVE: To identify the current status of specialist preterm labour (PTL) clinics and identify changes in management trends over the last 5 years following release of the NICE preterm birth (PTB) guidance. DESIGN: Postal Survey of Clinical Practice. SETTING: UK. POPULATION: All consultant-led obstetric units. METHODS: A questionnaire was sent by post to all 187 NHS consultant-led obstetric units. Units with a specialist PTL clinic were asked to answer a further six questions defining their protocol for risk stratification and management. MAIN OUTCOME MEASURES: Current practice in specialist PTL clinics. Changes in treatment trends over 5 years. RESULTS: Thirty-three PTL prevention clinics were identified, with 73% running weekly. NHS staff (84%) have replaced university staff as the lead clinicians (from 69% in 2012 to 21% in 2017), suggesting this clinic has become increasingly integrated with standard care for women at the highest risk of PTB. There has been a large shift from nearly half of clinics offering cerclage as primary treatment for short cervix to offering more choice (30%) between at least two of cerclage, vaginal progesterone or pessary and combinations of primary treatments (18%), demonstrating more equipoise among clinicians regarding therapies for short cervix. CONCLUSIONS: Over 5 years, there has been a 44% increase in the number of specialist PTL clinics in the UK. Although there is a better consensus over the target high-risk population, there is increasing heterogeneity among first-line treatments for short cervix. TWEETABLE ABSTRACT: UK PTB prevention clinics have increased by 44% over 5 years, with increasing clinical equipoise to best Rx for short cervix.

Severe primary autoimmune thrombocytopenia in pregnancy: a national cohort study.

OBJECTIVE: To quantify the incidence of severe autoimmune thrombocytopenia (ITP) in pregnancy in the UK, determine current treatment strategies, and establish maternal and neonatal morbidity and mortality associated with severe ITP in pregnancy. DESIGN: A prospective national cohort study. SETTING: UK. POPULATION: Women with severe ITP, defined as platelets <50 × 109 /L in pregnancy or antenatal treatment of isolated low platelets. METHODS: Data collected via the UK Obstetric Surveillance System (UKOSS) between 1 June 2013 and 31 January 2015 from all UK consultant-led obstetric units. MAIN OUTCOME MEASURE: Incidence of severe ITP in pregnancy. RESULTS: The estimated incidence of severe ITP in pregnancy is 0.83 per 10 000 maternities (95% CI 0.68-1.00). A total of 22 pregnant women (21%) did not receive any antenatal therapy, and 85 pregnant women (79%) received therapy. There was no difference between asymptomatic treated and untreated cohorts in severity of disease or outcome. Postpartum haemorrhage (51%) and severe postpartum haemorrhage (21%) was reported more frequently than the rate reported in the general pregnant population (5-10%). No neonates required treatment for thrombocytopenia and there were no cases of neonatal intracranial bleeding. CONCLUSIONS: Current UK management of severe ITP in pregnancy results in an exceptionally low morbidity and mortality for the neonate. Mothers with ITP remain at increased risk of severe postpartum haemorrhage, and should be delivered at units that have the capacity to manage severe PPH effectively. Whilst balancing the risks for pregnancy from prophylactic antenatal treatment in asymptomatic women against observed low disease morbidity, we may be over treating asymptomatic patients. TWEETABLE ABSTRACT: UKOSS study of severe ITP in pregnancy shows exceptionally low neonatal morbidity with current UK management.

AP2α controls the dynamic balance between miR-126&126* and miR-221&222 during melanoma progression.

Accumulating evidences have shown the association between aberrantly expressed microRNAs (miRs) and cancer, where these small regulatory RNAs appear to dictate the cell fate by regulating all the main biological processes. We demonstrated the responsibility of the circuitry connecting the oncomiR-221&222 with the tumor suppressors miR-126&126* in melanoma development and progression. According to the inverse correlation between endogenous miR-221&222 and miR-126&126*, respectively increasing or decreasing with malignancy, their enforced expression or silencing was sufficient for a reciprocal regulation. In line with the opposite roles of these miRs, protein analyses confirmed the reverse expression pattern of miR-126&126*-targeted genes that were induced by miR-221&222. Looking for a central player in this complex network, we revealed the dual regulation of AP2α, on one side directly targeted by miR-221&222 and on the other a transcriptional activator of miR-126&126*. We showed the chance of restoring miR-126&126* expression in metastatic melanoma to reduce the amount of mature intracellular heparin-binding EGF like growth factor, thus preventing promyelocytic leukemia zinc finger delocalization and maintaining its repression on miR-221&222 promoter. Thus, the low-residual quantity of these two miRs assures the release of AP2α expression, which in turn binds to and induces miR-126&126* transcription. All together these results point to an unbalanced ratio functional to melanoma malignancy between these two couples of miRs. During progression this balance gradually moves from miR-126&126* toward miR-221&222. This circuitry, besides confirming the central role of AP2α in orchestrating melanoma development and/or progression, further displays the significance of these miRs in cancer and the option of utilizing them for novel therapeutics.

CD99 regulates neural differentiation of Ewing sarcoma cells through miR-34a-Notch-mediated control of NF-κB signaling.

Sarcomas are mesenchymal tumors characterized by blocked differentiation process. In Ewing sarcoma (EWS) both CD99 and EWS-FLI1 concur to oncogenesis and inhibition of differentiation. Here, we demonstrate that uncoupling CD99 from EWS-FLI1 by silencing the former, nuclear factor-κB (NF-κB) signaling is inhibited and the neural differentiation program is re-established. NF-κB inhibition passes through miR-34a-mediated repression of Notch pathway. CD99 counteracts EWS-FLI1 in controlling NF-κB signaling through the miR-34a, which is increased and secreted into exosomes released by CD99-silenced EWS cells. Delivery of exosomes from CD99-silenced cells was sufficient to induce neural differentiation in recipient EWS cells through miR-34a inhibition of Notch-NF-κB signaling. Notably, even the partial delivery of CD99 small interfering RNA may have a broad effect on the entire tumor cell population owing to the spread operated by their miR-34a-enriched exosomes, a feature opening to a new therapeutic option.

Predicting preterm birth in women with previous preterm birth and cervical length ≥ 25 mm.

OBJECTIVE: To identify risk factors predicting subsequent spontaneous preterm birth or preterm prelabor rupture of membranes (PPROM) in a cohort of women with a history of spontaneous preterm birth and a cervical length of ≥ 25 mm at 20-24 weeks' gestation. METHODS: We identified all pregnant women who attended our preterm labor clinic between January 2010 and December 2012 because of previous spontaneous preterm birth or PPROM before 34 weeks. Women with a normal cervical length (defined as ≥ 25 mm) between 20 and 24 weeks' gestation were identified and included in the analysis. Maternal characteristics, obstetric history, shortest cervical length and gestational age at shortest cervical length of women who delivered preterm (before 37 weeks) were compared with those who delivered at or after 37 weeks in the index pregnancy. Multiple regression analysis was planned to examine the relationship between significant clinical and cervical-length variables to identify significant clinical predictors of spontaneous preterm birth among high-risk patients with a normal cervix between 20 and 24 weeks' gestation. RESULTS: Of 134 women with a normal cervix at 20-24 weeks, 28 (20.9%) delivered spontaneously or had PPROM before 37 weeks; of these 12 (9.0%) delivered before 34 weeks. None of the selected explanatory variables was predictive of recurrent preterm birth in this cohort. No correlation between absolute cervical length and gestational age at delivery was found (R = 0.01). CONCLUSION: In high-risk women with a cervical length of ≥ 25 mm at 20-24 weeks' gestation, demographic characteristics and absolute cervical length are not useful in predicting subsequent spontaneous preterm birth.

Oncogenic HoxB7 requires TALE cofactors and is inactivated by a dominant-negative Pbx1 mutant in a cell-specific manner.

The homeobox containing gene HoxB7 is functionally associated with melanoma growth promotion through the direct transactivation of bFGF. Accordingly, the introduction of HoxB7 in the breast cancer line SkBr3 (SkBr3/B7), strongly increases its tumorigenic properties. Here we show that in SkBr3/B7 cells, HoxB7 regulates the expression of TALE Hox cofactors by increasing Pbx2 and Prep1 and decreasing Pbx1. The functional requirement of Hox cofactors in the oncogenic activity of HoxB7 was proven with a dominant-negative Pbx1 mutant, Pbx1NT, which sequesters Prep1 in the cytoplasm. The less aggressive phenotype of the SkBr3/B7/PbxNT cells, evaluated in vitro as well as in vivo, correlated well with increased apoptosis, decreased cycling and up-regulation of p16 and p53. Tumor cell-type specific functional effects of Pbx1NT were observed, possibly related to the presence of different Hox genes in melanoma or breast adenocarcinoma DNA-protein ternary complexes.

Unilineage monocytopoiesis in hematopoietic progenitor culture: switching cytokine treatment at all Mo developmental stages induces differentiation into dendritic cells.

We have developed a new culture system whereby human hematopoietic progenitors purified from adult peripheral blood extensively proliferate and gradually differentiate into >95% pure monocytic (Mo) cells. At all developmental stages treatment with interleukin (IL)-4+granulocyte-macrophage colony-stimulating factor or IL-4+c-Kit-ligand+FLT-3 ligand switched the Mo precursors into dendritic cells (DCs). The switching capacity decreased only at the end of the culture, when most Mo cells matured to macrophages. Moreover, the Mo precursors were highly susceptible to transduction with lentiviral vectors: once switched to DCs, they maintained the transgene expression, as well as the phenotype and function of the DC lineage. Our results provide new insight into the potential role of the Mo lineage as a reservoir of DCs in vivo. Furthermore, the methodology for transduction of Mo precursors provides a tool to generate genetically modified, normally functioning DCs potentially useful for immunotherapy.

Relationship between intrafollicular concentrations of parathyroid hormone-related peptide (PTHrP) and steroid hormones in oestrogenic and non-oestrogenic ovarian follicles in the mare.

The objective of the present study was to determine whether parathyroid hormone-related peptide (PTHrP) is present in the equine follicular fluid and if so, how it is related to the follicular development in the horse. For this purpose, ovaries were collected from 40 Thoroughbred and Thoroughbred Cross mares at slaughter during the period from February to May. Normal growing follicles were dissected from the ovaries of each mare and their diameters measured. A total of 174 follicles was used in this study. The follicular fluid was aspirated from each follicle and assayed for PTHrP, oestradiol (E), testosterone (T) and progesterone (P). The follicles were classified as either oestrogenic or non-oestrogenic if the follicular fluid content of oestradiol was >40 or <40 ng/ml, respectively. PTHrP concentrations were significantly (P<0.05) higher in oestrogenic follicles, but T and P concentrations did not differ. Furthermore, E:T ratio was significantly (P<0.05) greater in oestrogenic follicles compared to the non-oestrogenic ones. The mean diameter of oestrogenic follicles was significantly (P<0.05) greater than that of non-oestrogenic ones. The higher concentrations of PTHrP observed in the follicular fluid of healthy oestrogenic follicles suggest that it may have a role in the control of ovarian function.

Parathyroid hormone-related peptide (38-94) amide stimulates ATP-dependent calcium transport in the Basal plasma membrane of the human syncytiotrophoblast.

The final step in the maternal-fetal transfer of calcium in the placenta involves transport against a concentration gradient across the syncytiotrophoblast basal plasma membrane (BM). Based on animal studies, it has been proposed that parathyroid hormone-related peptide (PTHrP) plays a major role in maintaining the maternal-fetal concentration gradient of calcium. In this study, we tested the hypothesis that a highly conserved mid-region fragment (38-94) of PTHrP directly affects the ATP-dependent calcium transport across BM isolated from full-term human placentas. PTHrP (38-94) stimulated ATP-dependent calcium transport at a concentration within the physiological range (5 pg/ml) and the effect (10-38% increase) was concentration dependent over the range 5 pg/ml to 5 ng/ml (n=8; P<0.05). In contrast, PTH, PTHrP (1-34), PTHrP (67-86) and calcitonin increased BM calcium transport only at concentrations much higher than physiological. The increased calcium uptake was inhibited by the protein kinase C (PKC) inhibitor chelerythrine (n=6; P<0.05). In addition, PTHrP (38-94) increased inositol trisphosphate (IP(3)) production and PKC phosphorylation in human placental BM (n=12; P<0.05). Our data indicate that PTHrP (38-94) stimulates Ca(2+)ATPase in the human syncytiotrophoblast BM vesicles by activating the IP(3)-DAG-PKC pathway. We suggest that PTHrP (38-94) is important in maintaining the calcium concentration gradient across the placental barrier in the human.

The absorption of phosphate ions from the ovine reticulorumen.

The reticulorumen is now recognised to be an important site of net absorption of phosphate ions from ruminal fluid containing phosphate concentrations appropriate to those found in normal farming practice. These rates of absorption were measured in vivo from solutions placed in the washed reticulorumen, isolated in situ, in conscious, trained sheep. Reducing the ruminal sodium concentration led to reduced absorption of phosphate, suggestive that phosphate and sodium fluxes across the apical wall of the ruminal epithelial cell are linked, as they are in the kidney. Increased absorption of short chain fatty acids led to enhanced absorption of phosphate ions. Conversely, inhibition of carbonic anhydrase activity, by the addition of 1 mM acetazolamide to the ruminal fluid, led to a reduction in phosphate absorption. An increase in the acidity of the ruminal fluid also increased the absorption of phosphate, as did an increase in the ruminal Ca(2+) concentration over the range 1-4 mmol per litre. It is suggested that these effects can be accounted for by a Na(+)/H(+) antiporter coupled with a phosphate/proton symporter in the apical membrane of the ruminal epithelial cell.

HOXB7: a key factor for tumor-associated angiogenic switch.

We had demonstrated previously a functional bridge between altered homebox (HOX) gene expression and tumor progression through HOXB7 transactivation of basic fibroblast growth factor. Here, we have studied whether HOXB7, in addition to basic fibroblast growth factor, may induce other genes directly or indirectly related to neoangiogenesis and tumor invasion. Parental, beta-galactosidase-transduced, and HOXB7-transduced SkBr3 cell lines were examined for the expression of several growth factors and growth factor receptors involved in the proliferative and angiogenic processes. Vascular endothelial growth factor, melanoma growth-stimulatory activity/growth-related oncogenene alpha, interleukin-8, and angiopoietin-2 were up-regulated by HOXB7 transduction. The exception was angiopoietin-1 expression that was abrogated. Additional analyses included the expression levels of enzymes such as matrix metalloprotease (MMP)-2 and MMP-9 and heparanase, capable of proteolytic degradation of extracellular matrix and basement membranes. Results showed an induction of only MMP-9. The functional implication of such a finding was tested using an in vitro coculture assay in a three-dimensional matrix. A delay of differentiation with persistent nests of proliferating cells was found in endothelial cells cocultured with HOXB7-transduced SkBr3 cells. Tumorigenicity of these cells has been evaluated in vivo. Xenograft into athymic nude mice showed that SkBr3/HOXB7 cells developed tumors in mice, either irradiated or not, whereas parental SkBr3 cells did not show any tumor take unless mice were sublethally irradiated. Comparison of tumor nodules for vascularization by CD-31 and CD-34 immunostaining revealed an increased number of blood vessels in tumors expressing HOXB7. Together, the results indicate HOXB7 as a key factor up-regulating a variety of proangiogenic stimuli. Thus, HOXB7 gene or protein is a target to aim at to inhibit tumor-associated neoangiogenesis, considering the number and the redundancy of proangiogenic molecules that should be targeted one by one to theoretically achieve the same effect.

Polyclonal expansion of CD3(+)/CD4(+)/CD56(+) large granular lymphocytes and autoimmunity associated with dysregulation of Fas/FasL apoptotic pathway.

Evidence is accumulating regarding CD95/CD95 ligand (Fas/FasL) pathway dysregulation in clonal diseases of the lymphohaemopoietic lineages. According to these observations, it has been proposed that this defect may represent one of the mechanisms of tumour progression. In large granular lymphocyte (LGL) leukaemia, dysregulated apoptosis may represent a key event in the development of malignancy and autoimmunity. This case report describes dysregulation of the Fas/FasL pathway in a chronic polyclonal expansion of CD3(+) LGLs associated with numerous serological immune abnormalities.

Effects of strontium on the absorption of calcium, magnesium and phosphate ions from the ovine reticulo-rumen.

The net absorption rates of strontium ions from the ovine reticulo-rumen, isolated in situ in trained conscious animals, were measured under controlled conditions. A linear positive response was obtained from the addition of Sr2+ ions to the artificial rumen fluid. This increase in the absorption of Sr was reflected in an increase in the plasma Sr concentration. In contrast to the discrimination observed elsewhere in favour of the absorption of Ca relative to Sr, the absorption rate of Sr from the reticulo-rumen was significantly greater than that of Ca, from solutions containing the same molar concentration. A graded increase in the Sr concentration in the ruminal fluid from 1 mmol/l to 4 mmol/l led to a corresponding reduction in the absorption rate of Ca but an increase in that of phosphate. The latter result is similar to that observed when the intra-ruminal concentration of Ca2+ ions is increased. It is suggested that Ca and Sr share a common pathway for absorption from the reticulo-rumen and that this may involve coupling with the absorption of phosphate ions.

The absorption of calcium ions from the ovine reticulo-rumen.

Net Ca2+ and Mg2+ absorption rates were measured in vivo from buffer solutions placed in the washed reticulo-rumen, isolated in situ in 30 conscious, trained sheep. An increase in concentration of short chain fatty acids (SCFA) in the buffer, over the range 0-50 mM, was shown to stimulate the net rates of absorption of Ca2+ and Mg2+ ions from the rumen. Similarly, the results of in vitro experiments, carried out with ovine rumen epithelium mounted in short-circuited Ussing chambers, showed that the absence of SCFA from the chamber fluid resulted in a reduction in Jnet Ca2+ caused by reduced flux of Ca2+ ions in the mucosal to serosal direction (Jms Ca2+). The addition of 1 mM acetazolamide, an inhibitor of carbonic anhydrase, to the ruminal buffer used in the in vivo experiments led to significant reductions in the net absorption rates of Ca2+ and Mg2+ ions in the presence of SCFA (50 mmol x l(-1)) but not in the absence of SCFA. However, in the in vitro experiments, the addition of 60 microM ethoxyzolamide had no significant effect on Jnet Ca2+. A reduction in pH of the intraruminal buffer in vivo from 6.8 to 5.4 led to significant increases in the net absorption rates of Ca2+ and Mg2+ ions, an effect which was duplicated for Ca2+ in preliminary in vitro experiments in which the pH of the mucosal buffer was reduced from 7.4 to 5.4. This stimulatory effect was confined to Jms Ca2+ and Jnet Ca2+. Ussing chambers were also used to demonstrate that Jnet Ca2+ was reduced by a high transmural potential difference (PD), caused by voltage clamping, independently of the mucosal K+ concentration. Both unidirectional Ca2+ fluxes consisted of a PD-dependent and a K+-insensitive PD-independent component. The latter may be represented by a Ca2+/ 2H+ antiporter. It is postulated that SCFA, and to a lesser extent H2CO3, can stimulate Jms Ca2+ by activation of an apical Ca2+/2H+ antiporter through the provision of protons within the ruminal epithelial cell. A mild reduction in ruminal pH may also lead to a similar stimulation of this putative electroneutral exchange.

The relaxant effects of parathyroid hormone(1-34) and parathyroid hormone-related protein(1-34) on ovine reticulo-ruminal smooth muscle in vivo.

The motility of the reticulo-rumen has been measured in trained, conscious sheep using inflated balloons temporarily introduced to selected regions of that forestomach. The frequency and amplitude of the contractions of the reticulum and both the A and B waves of contraction of the rumen were measured under the same conditions before, during and after the administration of an i.v. bolus of either parathyroid hormone (PTH(1-34)) or PTH-related protein (PTHrP(1-34)) followed by its i.v. infusion. These two peptides are known to share a common receptor in other organs, e.g. the kidney. In this study they both showed an inhibitory effect on reticulo-ruminal motility. The effect of PTHrP(1-34) on the rate of ruminal blood flow was also examined and a significant reduction observed, after a transient increase. The secretion of endogenous PTH(1-34) was stimulated by a 32% reduction in the plasma calcium ion concentration induced by an i.v. infusion of sodium citrate. Associated with this were significant reductions in reticulo-ruminal motility, e.g. the reduction in the mean amplitude of the reticular contractions reflected the reduction in plasma calcium ion concentration. When the PTH(1-34)/PTHrP(1-34) receptor was blocked with [Asn10,Leu11,D-Trp12]PTHrP(7-34) before and during the induction of hypocalcaemia, all but one of the parameters of reticulo-ruminal motility were normalized. Indeed, by the day following the administration of this blocking agent, all these parameters had returned to their normal range. It is concluded that stimulation of the PTH(1-34)/PTHrP(1-34) receptor in reticulo-ruminal smooth muscle reduces the motility of this tissue and may play a role in the depression of motility of the digestive tract which is characteristic of clinical milk fever in the dairy cow.