Pre-eclampsia screening in Denmark (PRESIDE): national validation study

OBJECTIVES

To investigate the predictive performance of the Fetal Medicine Foundation (FMF) first-trimester screening algorithm for pre-eclampsia in a Danish population and compare screening performance with that of the current Danish strategy, which is based on maternal risk factors.

METHODS

This was a prospective study of women with a singleton pregnancy attending for their first-trimester ultrasound scan and screening for aneuploidies at six Danish university hospitals between May 2019 and December 2020. Prenatal data on maternal characteristics and medical history were recorded, and measurements of mean arterial pressure (MAP), uterine artery pulsatility index (UtA-PI), serum pregnancy-associated plasma protein-A (PAPP-A) and serum placental growth factor (PlGF) were collected without performing a risk assessment for pre-eclampsia. Information on acetylsalicylic acid use was recorded. After delivery, pregnancy outcome, including gestational age at delivery and pre-eclampsia diagnosis, was recorded. Pre-eclampsia risk assessment for each woman was calculated blinded to outcome using the FMF screening algorithm following adjustment to the Danish population. Detection rates (DRs) of the FMF algorithm were calculated for a fixed screen-positive rate (SPR) of 10% and for the SPR achieved in the current Danish screening.

RESULTS

A total of 8783 pregnant women were included, with a median age of 30.8 (interquartile range (IQR), 28.1-33.9) years. The majority were white (95%), naturally conceiving (90%), non-smokers (97%) and had no family history of pre-eclampsia (96%). The median body mass index was 23.4 (IQR, 21.2-26.6) kg/m2 . A complete risk assessment including maternal characteristics, MAP, UtA-PI, PlGF and PAPP-A was available for 8156 women (92.9%). In these women, UtA-PI was measured bilaterally with a median value of 1.58 (IQR, 1.27-1.94) and the median resting MAP of 80.5 (IQR, 76.1-85.4) mmHg in two consecutive measurements. Among these, 303 (3.7%) developed pre-eclampsia, including 55 (0.7%) cases of pre-eclampsia with delivery < 37 weeks of gestation and 16 (0.2%) cases of pre-eclampsia with delivery < 34 weeks. At a SPR of 10%, combined screening using the FMF algorithm based on maternal characteristics, MAP, UtA-PI, PlGF and PAPP-A had a DR of 77.4% (95% CI, 57.6-97.2%) for pre-eclampsia with delivery < 34 weeks, 66.8% (95% CI, 54.4-79.1%) for pre-eclampsia with delivery < 37 weeks and 44.1% (95% CI, 38.5-49.7%) for pre-eclampsia with delivery at any gestational age. The current Danish screening strategy using maternal risk factors detected 25.0% of women with pre-eclampsia with delivery < 34 weeks and 19.6% of women with pre-eclampsia with delivery < 37 weeks at a SPR of 3.4%. When applying the FMF algorithm including maternal characteristics, MAP, UtA-PI and PlGF at the fixed SPR of 3.4%, the DRs were 60.5% (95% CI, 36.9-84.1%) for PE with delivery < 34 weeks and 45.2% (95% CI, 32.0-58.5%) for PE with delivery < 37 weeks.

CONCLUSION

In this large Danish multicenter study, the FMF algorithm based on maternal characteristics, MAP, UtA-PI, PlGF and PAPP-A predicted 77.4% of cases with pre-eclampsia with delivery < 34 weeks and 66.8% of cases with pre-eclampsia with delivery < 37 weeks of gestation at a SPR of 10%, suggesting that the performance of the algorithm in a Danish cohort matches that in other populations. © 2023 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Maternal exposure to UV filters: associations with maternal thyroid hormones, IGF-I/IGFBP3 and birth outcomes

BACKGROUND

Several chemical UV filters/absorbers ('UV filters' hereafter) have endocrine-disrupting properties in vitro and in vivo. Exposure to these chemicals, especially during prenatal development, is of concern.

OBJECTIVES

To examine maternal exposure to UV filters, associations with maternal thyroid hormone, with growth factor concentrations as well as to birth outcomes.

METHODS

Prospective study of 183 pregnant women with 2nd trimester serum and urine samples available. Maternal concentrations of the chemical UV filters benzophenone-1 (BP-1) and benzophenone-3 (BP-3) in urine and 4-hydroxy-benzophenone (4-HBP) in serum were measured by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The relationships between 2nd trimester maternal concentrations of the three chemical UV filters and maternal serum concentrations of thyroid hormones and growth factors, as well as birth outcomes (weight, height, and head and abdominal circumferences) were examined.

RESULTS

Positive associations between maternal serum concentrations of 4-HBP and triiodothyronine (T₃), thyroxine (T₄), insulin-like growth factor I (IGF-I) and its binding protein IGFBP3 were observed in mothers carrying male fetuses. Male infants of mothers in the middle 4-HBP exposure group had statistically significantly lower weight and shorter head and abdominal circumferences at birth compared to the low exposure group.

CONCLUSIONS

Widespread exposure of pregnant women to chemical UV filters and the possible impact on maternal thyroid hormones and growth factors, and on fetal growth, calls for further studies on possible long-term consequences of the exposure to UV filters on fetal development and children's health.

Presence of benzophenones commonly used as UV filters and absorbers in paired maternal and fetal samples

BACKGROUND

Previous studies have demonstrated widespread exposure of humans to certain benzophenones commonly used as UV filters or UV absorbers; some of which have been demonstrated to have endocrine disrupting abilities.

OBJECTIVES

To examine whether benzophenones present in pregnant women pass through the placental barrier to amniotic fluid and further to the fetal blood circulation.

METHODS

A prospective study of 200 pregnant women with simultaneously collected paired samples of amniotic fluid and maternal serum and urine. In addition, unique samples of human fetal blood (n=4) obtained during cordocentesis: and cord blood (n=23) obtained at delivery, both with paired maternal samples of serum and urine collected simultaneously, were used. All biological samples were analyzed by TurboFlow-liquid chromatography - tandem mass spectrometry for seven different benzophenones.

RESULTS

Benzophenone-1 (BP-1), benzophenone-3 (BP-3), 4-methyl-benzophenone (4-MBP), and 4-hydroxy-benzophenone (4-HBP) were all detectable in amniotic fluid and cord blood samples and except 4-HBP also in fetal blood; albeit at a low frequency. BP-1 and BP-3 were measured at ~10-times lower concentrations in fetal and cord blood compared to maternal serum and 1000-times lower concentration compared to maternal urine levels. Therefore BP-1 and BP-3 were only detectable in the fetal circulation in cases of high maternal exposure indicating some protection by the placental barrier. 4-MBP seems to pass into fetal and cord blood more freely with a median 1:3 ratio between cord blood and maternal serum levels. Only for BP-3, which the women seemed to be most exposed to, did the measured concentrations in maternal urine and serum correlate to concentrations measured in amniotic fluid. Thus, for BP-3, but not for the other tested benzophenones, maternal urinary levels seem to be a valid proxy for fetal exposure.

CONCLUSIONS

Detectable levels of several of the investigated benzophenones in human amniotic fluid as well as in fetal and cord blood calls for further investigations of the toxicokinetic and potential endocrine disrupting properties of these compounds in order for better assessment of the risk to the developing fetus.

Effects of forage neutral detergent fibre and time after feeding on medial and ventral rumen pH and volatile fatty acids concentration in heifers fed highly digestible grass/clover silages

The major microbial fermentation of forages and production of volatile fatty acids (VFA) takes place in the medial part of the rumen, whereas the absorption of VFA occurs through the rumen epithelium, for example the ventral sac. The objective was to study effects of forage neutral detergent fibre (NDF) content and time after feeding on the medial to ventral VFA and pH gradient as well as rumen motility in the rumen of heifers fed grass/clover silages. Four silages were harvested at different growth stages with NDF contents of 31–45% of DM and in vitro organic matter digestibilities of 75–82% and fed to four rumen-fistulated Jersey heifers at 90% of ad libitum level in a Latin square design, with half the ration fed at 0800 hours and 1530 hours. Rumen fluid was sampled hourly from 0730 hours to 1530 hours in the medial and ventral rumen, and analysed for pH and concentrations of VFA, L-lactic acid, and ammonia to assess ruminal chemical gradient. Reticular contractions were continuously recorded by a pressure transducer. Time relative to feeding affected rumen parameters as pH was generally lower and VFA content greater in medial compared with ventral rumen fluid. Greater NDF content of the silage caused lower VFA concentration and higher pH in the rumen mat, and therefore the gradient diminished at greater NDF content in the silages; an effect probably caused by reduced organic matter digestibility rather than digesta NDF properties. This study therefore suggests that VFA production decreased with greater NDF content of forages, whereas intra-ruminal equilibration increased.

Recording rumination time by a rumination monitoring system in Jersey heifers fed grass/clover silage and hay at three feeding levels

This study was conducted with the objective to validate a rumination monitoring system (RMS). The RMS was developed by SCR Engineers Ltd. (Netanya, Israel) to record individual rumination times in commercial dairy herds. Four heifers were fed 4 forage types at 3 feeding levels in 4 periods in a Latin square design. The forage types were spring growth of grass/clover harvested early (May 9) and late (May 25) conserved as silage and hay, creating 4 forage types: early harvest silage (ES), early harvest hay (EH), late harvest silage (LS), and late harvest hay (LH). Feeding levels were ad libitum, 90% of ad libitum, and 60% of ad libitum. Data were collected for 24 h at ad libitum feeding level, for 96 h at 90% of ad libitum, and for 24 h at 60% of ad libitum. Rumination time was recorded by the RMS in minutes per 2-h interval (RT(RMS2_i)) and per 24-h interval (RT(RMS24)). As a reference method, rumination time was recorded by chewing halters identifying rumination time by jaw movements (JM) and was accumulated into minutes per 2-h interval (RT(JM2_i)) and per 24-h interval (RT(JM24)) over the same time intervals as RT(RMS2_i) and RT(RMS24). Differences between RT(RMS2_i) and RT(JM2_i) were observed for EH, LS, and LH, with differences of 3.4 (P < 0.001), 1.1 (P = 0.03), and 3.3 (P < 0.001) min per 2-h interval. In addition, feeding restrictively at 90% and 60% of ad libitum resulted in greater rumination time recorded by the RMS compared to JM, with differences of 2.6 min per 2-h interval (P < 0.001) for 90% of ad libitum and 1.6 min per 2-h interval (P = 0.01) for 60% of ad libitum. Further, the differences between rumination times recorded by the RMS compared to JM were different among the 4 heifers. Despite these effects, rumination time recorded by the RMS correlated well with rumination time recorded by JM with correlation between RT(RMS2_i) and RT(JM2_i) of r = 0.91 (P < 0.001) and between RT(RMS24) and RT(JM24) of r = 0.79 (P < 0.001).

Temporal effects of maternal and pregnancy characteristics on serum pregnancy-associated plasma protein-A and free β-human chorionic gonadotropin at 7-14 weeks' gestation

OBJECTIVE

The aim of this study was to investigate gestational age-dependent effects of racial origin, smoking status and mode of conception on maternal serum levels of free β-human chorionic gonadotropin (β-hCG) and pregnancy-associated plasma protein-A (PAPP-A) at 7-14 weeks' gestation.

METHODS

This was an analysis of data from prospective first-trimester combined screening for aneuploidies in singleton pregnancies, with β-hCG and PAPP-A measured at 7 + 1 to 14 + 3 weeks' gestation. We included 27,908 pregnancies from three centers in the U.K. and 125,461 pregnancies from 22 centers in Denmark, all with known normal fetal karyotype or resulting in the birth of a phenotypically normal neonate. Multiple regression modelling of log10 -transformed marker concentrations was used to produce log10 multiple of the median (MoM) values for free β-hCG and PAPP-A and to examine pregnancy characteristics that have significant effects on marker concentrations.

RESULTS

Serum free β-hCG and PAPP-A concentrations were significantly affected by gestational age, maternal weight, racial origin, parity, smoking and mode of conception. There were significant gestational age-dependent effects attributed to Afro-Caribbean race, smoking and conception through in-vitro fertilization (IVF) on PAPP-A and free β-hCG levels. In women of Afro-Caribbean race there was a weekly increase in PAPP-A of 5.3% and in free β-hCG of 1.8%. In smokers there was a weekly decrease in PAPP-A of 2.4% and in free β-hCG of 1.6%. In cases of IVF conceptions there was a weekly increase in PAPP-A of 4.5% and in free β-hCG of 4.6%.

CONCLUSIONS

Serum free β-hCG and PAPP-A concentrations at 7-14 weeks' gestation are affected by several pregnancy characteristics. The effects of Afro-Caribbean race, smoking and IVF conception change with gestational age.

Prospective study evaluating performance of first-trimester combined screening for trisomy 21 using repeat sampling of maternal serum markers PAPP-A and free β-hCG

OBJECTIVE

To prospectively evaluate the performance of first-trimester combined screening for trisomy 21 using the biochemical markers pregnancy-associated plasma protein-A (PAPP-A) and free beta-human chorionic gonadotropin (free β-hCG) obtained before and at the time of the nuchal translucency (NT) scan.

METHODS

Three fetal medicine departments in Denmark participated in the study. Screening for trisomy 21 was set up as a two-step approach with blood sampling performed before the NT scan (early sample) and again at the time of the NT scan (late sample). PAPP-A and free β-hCG were measured on both the early and late samples. Age-standardized detection and false-positive rates for different screening protocols were calculated.

RESULTS

We collected two blood samples in 27 pregnancies affected by trisomy 21 and in 3891 control pregnancies. The early samples were taken between gestational ages 8 + 0 and 13 + 6 weeks, and the late samples between 11 + 3 and 14 + 6 weeks. The median interval between the samples was 17 (range, 1-40) days. We found a significantly better estimated screening performance when using early sampling vs late sampling (P < 0.05). With a risk cut-off of 1 in 100, at the time of the risk assessment the estimated detection and false-positive rates when using the early sample were 91% (95% CI, 81-98%) and 1.6% (95% CI, 1.3-2.0%), respectively. For fixed false-positive rates the highest detection rates were achieved using both blood samples. When comparing early sampling vs double sampling there was no significant difference in screening performance.

CONCLUSION

In combined first-trimester screening for trisomy 21, use of early sampling with measurement of PAPP-A and free β-hCG before the time of the NT scan can optimize screening performance. Using maternal serum markers obtained both before and at the time of the NT scan has the potential to further improve performance, but larger studies are needed to confirm this potential.

Glucocorticoids and histone deacetylase inhibitors cooperate to block the invasiveness of basal-like breast cancer cells through novel mechanisms

Aggressive cancers often express E-cadherin in cytoplasmic vesicles rather than on the plasma membrane and this may contribute to the invasive phenotype of these tumors. Therapeutic strategies are not currently available that restore the anti-invasive function of E-cadherin in cancers. MDA-MB-231 cells are a frequently used model of invasive triple-negative breast cancer, and these cells express low levels of E-cadherin that is mislocalized to cytoplasmic vesicles. MDA-MB-231 cell lines stably expressing wild-type E-cadherin or E-cadherin fused to glutathione S-transferase or green fluorescent protein were used as experimental systems to probe the mechanisms responsible for cytoplasmic E-cadherin localization in invasive cancers. Although E-cadherin expression partly reduced cell invasion in vitro, E-cadherin was largely localized to the cytoplasm and did not block the invasiveness of the corresponding orthotopic xenograft tumors. Further studies indicated that the glucocorticoid dexamethasone and the highly potent class I histone deacetylase (HDAC) inhibitor largazole cooperated to induce E-cadherin localization to the plasma membrane in triple-negative breast cancers, and to suppress cellular invasion in vitro. Dexamethasone blocked the production of the cleaved form of the CDCP1 (that is, CUB domain-containing protein 1) protein (cCDCP1) previously implicated in the pro-invasive activities of CDCP1 by upregulating the serine protease inhibitor plasminogen activator inhibitor-1. E-cadherin preferentially associated with cCDCP1 compared with the full-length form. In contrast, largazole did not influence CDCP1 cleavage, but increased the association of E-cadherin with γ-catenin. This effect on E-cadherin/γ-catenin complexes was shared with the nonisoform selective HDAC inhibitors trichostatin A (TSA) and vorinostat (suberoylanilide hydroxamic acid, SAHA), although largazole upregulated endogenous E-cadherin levels more strongly than TSA. These results demonstrate that glucocorticoids and HDAC inhibitors, both of which are currently in clinical use, cooperate to suppress the invasiveness of breast cancer cells through novel, complementary mechanisms that converge on E-cadherin.

Skin temperature measured by infrared thermography after specific ultrasound-guided blocking of the musculocutaneous, radial, ulnar, and median nerves in the upper extremity

BACKGROUND

Sympathetic block causes vasodilatation and increases in skin temperature (T(s)). However, the T(s) response after specific nerve blocking is unknown. In this study, we hypothesized that T(s) would increase after specific blocking of the nerve innervating that area.

METHODS

Forty-six patients undergoing hand surgery were included. We performed ultrasound-guided, specific nerve blocking of either the musculocutaneous, radial, ulnar, or median nerve in each patient and analysed T(s) in the forearm and hand at 2 min intervals in the following 22 min by the use of infrared thermography. Areas of interest corresponding to the cutaneous innervation area of each of the four nerves were defined and the mean T(s) in each area was analysed.

RESULTS

Specific blocking of the ulnar and median nerves caused a substantial increase in mean (sd) T(s) in the areas innervated by these nerves [5.2 (3.2)°C and 5.1 (2.5)°C, respectively; both P<0.0001]. The increase was even larger at the fingertips. Median nerve blocking also increased T(s) in the area of the hand innervated by the radial nerve (P<0.0001). However, T(s) did not increase in any area after either musculocutaneous or radial nerve blocking.

CONCLUSIONS

Specific blocking of the ulnar and median nerve causes substantial increases in T(s) in specific areas of the hand. In contrast, the specific blocking of the musculocutaneous or radial nerve does not increase T(s). Further studies are needed to clarify if these findings can be used to objectively evaluate brachial plexus block success.

Visceral leishmaniasis diagnosed in a patient with MALT lymphoma

We report a case of visceral leishmaniasis in a 66-year-old female with a history of MALT lymphoma in the gastrointestinal tract. The patient presented with major hemorrhage per rectum and perforation of the small intestine. Due to unexplained decreasing platelets, lymphoma bone marrow involvement was suspected and bone marrow examination was performed. Surprisingly, Leishman-Donovan bodies were detected. The low platelet count, caused by the combination of MALT lymphoma and visceral leishmaniasis, appears to have aggravated the symptoms of the intestinal lymphoma. Leishmaniasis should be suspected even among asymptomatic patients with immune compromising illnesses and a travel history to areas where leishmaniasis is endemic.

The effect of subclinical hypocalcaemia induced by Na2EDTA on the feed intake and chewing activity of dairy cows

The effects of induced subclinical hypocalcaemia (SCHC) on feed intake and chewing activity during eating and rumination were studied in dairy cows. Two non-lactating and non-pregnant cows were subjected to three different treatments, with one test per day, such that the plasma free (ionized) calcium (FCa) concentration was maintained at the eucalcaemic level or at one of two constant SCHC levels. The cows and test days followed a 2 x 3 crossover design. SCHC was maintained for 7 h by repeatedly infusing 5% Na2EDTA so that constant FCa concentrations of 0.8 mmol/L or 0.6 mmol/L in plasma were achieved. Control conditions were achieved by infusing isotonic saline. Feed intake and the number of the rumination periods were recorded during test days. The proportion of feed eaten during each test meal (EatPro) was related to the mean plasma FCa. An almost linear decrease in EatPro was observed when the plasma FCa was 0.6-0.9 mmol/L. The cows showed no other clinical signs of hypocalcaemia during Na2EDTA-infusion. The time spent chewing during eating and rumination, and the number of rumination periods during a test day, decreased with a decline in plasma FCa concentration. It was concluded that induced SCHC depresses the feed intake and ruminative activity of dairy cows.

Mutation of yeast Eug1p CXXS active sites to CXXC results in a dramatic increase in protein disulphide isomerase activity

Protein disulphide isomerase (PDI) is an essential protein which is localized to the endoplasmic reticulum of eukaryotic cells. It catalyses the formation and isomerization of disulphide bonds during the folding of secretory proteins. PDI is composed of domains with structural homology to thioredoxin and with CXXC catalytic motifs. EUG1 encodes a yeast protein, Eug1p, that is highly homologous to PDI. However, Eug1p contains CXXS motifs instead of CXXC. In the current model for PDI function both cysteines in this motif are required for PDI-catalysed oxidase activity. To gain more insight into the biochemical properties of this unusual variant of PDI we have purified and characterized the protein. We have furthermore generated a number of mutant forms of Eug1p in which either or both of the active sites have been mutated to a CXXC sequence. To determine the catalytic capacity of the wild-type and mutant forms we assayed activity in oxidative refolding of reduced and denatured procarboxypeptidase Y as well as refolding of bovine pancreatic trypsin inhibitor. The wild-type protein showed very little activity, not only in oxidative refolding but also in assays where only isomerase activity was required. This was surprising, in particular since mutant forms of Eug1p containing a CXXC motif displayed activity close to that of genuine PDI. These results lead us to propose that general disulphide isomerization is not the main function of Eug1p in vivo.

[Uncomplicated gallstone disease and pregnancy]

Pregnancy is associated with an increased incidence of gallstones. However, most gallstones disappear spontaneously after pregnancy without having given any symptoms. New knowledge regarding the pathophysiology confirms changes in the motility of the gallbladder and the flow dynamics and lithogenicity of the bile. The studies have also shown, that these changes resolve completely after labour, which might explain the disappearance of most of the gallstones. These conditions support a conservative attitude towards treatment of gallstone disease during pregnancy. In case cholecystectomy is indicated, laparoscopic intervention seems safe during pregnancy and most optimal during the second trimester where the organogenesis of the fetus is completed and where the size of the uterus does not interfere with the operation technically. Laparoscopic cholecystectomy should under all circumstances be done in departments with routine in laparoscopic operations and with the possibility of gynaecological assistance, in case it is needed.

Salicylate-induced growth arrest is associated with inhibition of p70s6k and down-regulation of c-myc, cyclin D1, cyclin A, and proliferating cell nuclear antigen

Salicylate and its pro-drug form aspirin are widely used medicinally for their analgesic and anti-inflammatory properties, and more recently for their ability to protect against colon cancer and cardiovascular disease. Despite the wide use of salicylate, the mechanisms underlying its biological activities are largely unknown. Recent reports suggest that salicylate may produce some of its effects by modulating the activities of protein kinases. Since we have previously shown that the farnesyltransferase inhibitor l-744, 832 inhibits cell proliferation and p70(s6k) activity, and salicylate inhibits cell proliferation, we examined whether salicylate affects p70(s6k) activity. We find that salicylate potently inhibits p70(s6k) activation and phosphorylation in a p38 MAPK-independent manner. Interestingly, low salicylate concentrations (</=250 microm) inhibit p70(s6k) activation by phorbol myristate acetate, while higher salicylate concentrations (>/=5 mm) are required to block p70(s6k) activation by epidermal growth factor + insulin-like growth factor-1. These data suggest that salicylate may selectively inhibit p70(s6k) activation in response to specific stimuli. Inhibition of p70(s6k) by salicylate occurs within 5 min, is independent of the phosphatidylinositol 3-kinase pathway, and is associated with dephosphorylation of p70(s6k) on its major rapamycin-sensitive site, Thr(389). A rapamycin-resistant mutant of p70(s6k) is resistant to salicylate-induced Thr(389) dephosphorylation.

Optimised extraction of folic acid from multivitamin-mineral preparations for liquid chromatographic analysis

Degradation of folic acid may occur during extraction of multivitamin-mineral preparations. The degradation may be caused by presence of ions such as Fe3+ and Cu2+, however, the buffer composition may also be critical. This study presents an optimised extraction procedure tested on 24 different products of multivitamin-mineral tablets. The present method yielded mean recoveries of 97% (n = 20) for folic acid and prevented degradation of folic acid in at least 24 h in extracts from multivitamin-mineral tablets.

Post-exercise facilitation of compound muscle action potentials evoked by transcranial magnetic stimulation in healthy subjects

Post-exercise facilitation (PEF) of motor evoked potentials (MEPs) was studied by transcranial magnetic stimulation in 15 healthy subjects following standardized and controlled isometric contraction of the biceps brachii muscle. PEF was highly dependent on the time delay (TD) from muscle relaxation to delivery of the magnetic stimulus and only to a minor degree on the duration of the maintained muscular contraction of 2, 4, and 6 s. In addition, PEF was unaffected by the contraction levels of 25%, 50%, and 100% of maximal voluntary contraction (MVC). There was a linear relationship between the log amplitude of the post-exercise MEPs and the TD. The time point at which PEF had vanished was calculated to be 15.2 s. In order to challenge the question whether segmental and/or suprasegmental mechanisms are primarily responsible for PEF, MEPs and H-reflexes were recorded from the soleus muscle following a sustained plantar flexion at the ankle joint in three healthy subjects. PEF of MEPs was present at a TD of 1000 ms following a sustained contraction of 6 s at a level of 50% of MVC. It was accompanied by a pronounced decrease in the soleus H-reflex amplitude at a TD of 1000 ms.

Inactivation of the transforming growth factor beta type II receptor in human small cell lung cancer cell lines

Transforming growth factor beta (TGF-beta) exerts a growth inhibitory effect on many cell types through binding to two types of receptors, the type I and II receptors. Resistance to TGF-beta due to lack of type II receptor (RII) has been described in some cancer types including small cell lung cancer (SCLC). The purpose of this study was to examine the cause of absent RII expression in SCLC cell lines. Northern blot analysis showed that RII RNA expression was very weak in 16 of 21 cell lines. To investigate if the absence of RII transcript was due to mutations, we screened the poly-A tract for mutations, but no mutations were detected. Additional screening for mutations of the RII gene revealed a GG to TT base substitution in one cell line, which did not express RII. This mutation generates a stop codon resulting in predicted synthesis of a truncated RII of 219 amino acids. The nature of the mutation, which has not previously been observed in RII, has been linked to exposure to benzo[a]-pyrene, a component of cigarette smoke. Since RII has been mapped to chromosome 3p22 and nearby loci are often hypermethylated in SCLC, it was examined whether the lack of RII expression was due to hypermethylation. Southern blot analysis of the RII promoter did not show altered methylation patterns. The restriction endonuclease pattern of the RII gene was altered in two SCLC cell lines when digested with Smal. However, treatment with 5-aza-2'-deoxycytidine did not induce expression of RII mRNA. Our results indicate that in SCLC lack of RII mRNA is not commonly due to mutations and inactivation of RII transcription was not due to hypermethylation of the RII promoter or gene. Thus, these data show that in most cases of the SCLC cell lines, the RII gene and promoter is intact in spite of absent RII expression. However, the nature of the mutation found could suggest that it was caused by cigarette smoking.

Inhibition of DNA synthesis by a farnesyltransferase inhibitor involves inhibition of the p70(s6k) pathway

Previously, the protein farnesyltransferase inhibitor (FTI), L-744, 832, has been shown to inhibit the proliferation of a number of tumor cell lines in vitro in a manner that correlated with the inhibition of the mitogen-activated protein kinase cascade. Here we show that FTI inhibits p70(s6k) phosphorylation in mammary tumors in vivo in transgenic mice. Furthermore, in a mouse keratinocyte cell line, FTI inhibits p70(s6k) phosphorylation and activity and inhibits PHAS-1 phosphorylation in vitro in both rapidly growing cells and in growth factor-stimulated quiescent cells. Dominant-negative Ras expression inhibits p70(s6k) stimulation by epidermal growth factor, demonstrating a requirement for Ras activity during p70(s6k) activation. FTI does not inhibit protein kinase B phosphorylation on Ser473, indicating that FTI does not act by inhibiting phosphatidylinositol 3-kinase. FTI also inhibits DNA synthesis in keratinocytes, and inhibition of DNA synthesis correlates closely with p70(s6k) inhibition. Rapamycin, an inhibitor of p70(s6k) and PHAS-1 phosphorylation, causes a 30-45% reduction in DNA synthesis in keratinocytes, while FTI induces an 80-90% reduction in DNA synthesis. These observations suggest that alteration of p70(s6k) and PHAS-1 function by FTI are responsible for a substantial portion of the growth-inhibitory properties of FTI. Together, these data demonstrate that p70(s6k) and PHAS-1 are novel downstream targets of FTI and suggest that the anti-tumor properties of FTI are probably due to the inhibition of multiple mitogenic pathways.

Treatment with farnesyl-protein transferase inhibitor induces regression of mammary tumors in transforming growth factor (TGF) alpha and TGF alpha/neu transgenic mice by inhibition of mitogenic activity and induction of apoptosis

Mouse mammary tumor virus-transforming growth factor alpha (MMTV-TGF alpha) and MMTV-TGF alpha/neu transgenic mice develop mammary tumors after a long latency and therefore provide useful model systems for breast cancer with its recognized activation of receptor tyrosine kinase signaling. We used these mice to study the antitumor effect of L-744,832 (FTI), a potent and selective inhibitor of farnesyl-protein transferase, and hence of Ras function. A total of 55 mice were assigned randomly to treatment with FTI or vehicle, and one-half of the mice were crossed over after initial treatment to the opposite group. L-744,832 induced reversible regression of mammary tumors that was paralleled by a decrease in serum levels of TGF alpha secreted by the tumor cells. There was no difference in response to treatment with FTI between MMTV-TGF alpha mice, in which tumorigenesis was accelerated by multiparity or the chemical carcinogen 7,12-dimethylbenzanthracene, and MMTV-TGF alpha/neu mice. The tumor histological type had no impact on FTI sensitivity. For mechanistic analyses, tumor excision biopsies were obtained from 12 mice before and after treatment with L-744,832. In these samples, tumor regression was paralleled biochemically by inhibition of mitogen-activated protein kinase activity and biologically by an increase in G1-phase and decrease in S-phase fractions, as well as induction of apoptosis. These results suggest that the potential clinical use of FTI could be expanded to include cancers harboring activated receptor tyrosine kinases as well as those containing activated Ras.

Fibrolytic enzyme treatment of barley grain and source of forage in high-grain diets fed to growing cattle

We conducted a study to determine the effects of treating barley grain with a fibrolytic enzyme mixture on chewing activities, ruminal fermentation, and total tract digestibility in cattle. We also investigated the potential benefits of using barley straw rather than barley silage as a roughage source in high-grain diets for feedlot cattle. Steers were given ad libitum access to one of four diets that consisted of 95% barley-based concentrate and 5% forage (DM basis). The concentrate was either control or enzyme-treated, and the forage was either barley silage or barley straw. Applying the enzyme mixture onto the barley lowered the concentrations of dietary ADF and NDF. However, it is not certain when this fiber hydrolysis occurred relative to feed consumption because the fiber analyses were conducted after the study was completed. Enzyme treatment of barley increased total tract dietary ADF digestibility by 28% (P<.05). Acetate-to-propionate ratio tended to decrease, which suggests that enzymes may have increased ruminal starch digestion as a result of enhanced digestion of barley hulls. Replacing silage with straw increased ADF intake (P<.05) and resulted in 1-h/d increase in rumination time (P<.05). Even though there was no effect of diet on ruminal pH, replacing silage with straw increased ruminal acetate, as a percentage of total VFA, and total tract ADF digestion (P<.01). This study demonstrates that using a fibrolytic enzyme mixture in high-grain diets that contain mainly barley grain can improve fiber digestion and grain utilization, but the mode of action is unclear. Straw can be used rather than silage to increase the effective fiber content of a high-grain feedlot diet.

High value of the radiobiological parameter Dq correlates to expression of the transforming growth factor beta type II receptor in a panel of small cell lung cancer cell lines

Our panel of SCLC cell lines have previously been examined for their radiobiological characteristics and sensitivity to treatment with TGF beta 1. In this study we examined the possible correlations between radiobiological parameters and the expression of the TGF beta type II receptor (TGF beta-rII). We have, in other studies, shown that the presence of TGF beta-rII was mandatory for transmitting the growth inhibitory effect of TGF beta. The results showed a statistically significant difference in Dq, i.e. the shoulder width of the survival curve, between cell lines expressing TGF beta-rII and cell lines which did not express the receptor (P = 0.01). Cell lines expressing TGF beta-rII had a high Dq-value. TGF beta-rII expression did not correlate with any other radiobiological parameters. We suggest that an intact growth inhibitory pathway mediated by the TGF beta-rII may have a significant role for the repair of radiation induced DNA damage in SCLC.

Technical note: reversible re-entrant cannulation of the parotid duct in cattle using a new injection anesthesia regimen

A new method for reversible reentrant cannulation of the parotid duct in cattle by use of an injectable anesthetic regimen is described. Ruminal contents were removed before anesthesia instead of food deprivation. The parotid duct was dilated by means of a long hemostatic forceps: its jaws were encased in a piece of plastic tube, and the tip was extended by a piece of flexible wire. A polyethylene parotid catheter was inserted into the dilated duct and passed through the cheek. The saliva was re-directed back into the mouth via a silicone tube through another fistula in the cheek. The cannulations were maintained for 3 to 11 wk and two cows were recannulated three to five times in both parotid ducts without problems. No pathological changes of the mouth epithelium were found at slaughter. The rate of flow from the ducts during rest, ruminating, and eating were 5 to 20, 25 to 50, and 40 to 75 mL/min, respectively.

Expression and autoregulation of transforming growth factor beta receptor mRNA in small-cell lung cancer cell lines

In small-cell lung cancer cell lines resistance to growth inhibition by transforming growth factor (TGF)-beta 1, was previously shown to correlate with lack of TGF-beta receptor I (RI) and II (RII) proteins. To further investigate the role of these receptors, the expression of mRNA for RI, RII and beta-glycan (RIII) was examined. The results showed that loss of RII mRNA correlated with TGF-beta 1 resistance. In contrast, RI-and beta-glycan mRNA was expressed by all cell lines, including those lacking expression of these proteins. According to Southern blot analysis, the loss of type II mRNA was not due to gross structural changes in the gene. The effect of TGF-beta 1 on expression of TGF-beta receptor mRNA (receptor autoregulation) was examined by quantitative Northern blotting in four cell lines with different expression of TGF-beta receptor proteins. In two cell lines expressing all three TGF-beta receptor proteins beta-glycan mRNA was rapidly down-regulated and this effect was sustained throughout the 24 h observation period. RI and RII mRNAs were slightly increased 24 h after treatment. In one cell line sensitive to growth inhibition by TGF-beta, 1 but lacking beta-glycan expression, and one cell line expressing only beta-glycan and thus TGF-beta 1 -resistant, no autoregulation of mRNA of either TGF-beta receptor was demonstrated. The results suggest that TGF-beta 1 regulates the expression of its receptors, in particular beta-glycan, and that this effect is dependent on co-expression of beta-glycan, RI and RII.

Acquired TGF beta 1 sensitivity and TGF beta 1 expression in cell lines established from a single small cell lung cancer patient during clinical progression

Three small cell lung cancer cell lines established from a single patient during longitudinal follow-up were examined for in vitro expression of TGF beta and TGF beta receptors, i.e. the components of an autocrine loop. GLC 14 was established prior to treatment, GLC 16 on relapse after chemotherapy and GLC 19 on recurrence after radiotherapy. TGF beta was detected by ELISA and TGF beta receptors by chemical crosslinking to radiolabelled TGF beta 1. Furthermore, TGF beta and TGF beta receptor mRNAs were detected by northern blot analysis. Expression of type II TGF beta receptor mRNA and protein was found in GLC 16 and GLC 19. These cell lines were also growth inhibited by exogenously administrated TGF beta 1. TGF beta 1 mRNA and protein in its latent form was only expressed in the radiotherapy-resistant cell line, GLC 19. The results indicate that disease progression in this patient was paralleled by a gain in sensitivity to the growth inhibition by TGF beta 1 due to type II TGF beta receptor, and a gain of latent TGF beta 1 protein. Lack of type II receptor expression in GLC 14, which was also resistant to growth inhibition by exogenous TGF beta 1, was not due to gross structural changes in the type II receptor gene, as examined by Southern blotting. Also, the type I receptor could not be detected by ligand binding assay in this cell line, despite expression of mRNA for this receptor. This agrees with previous findings that type I receptor cannot bind TGF beta 1 without co-expression of the type II receptor.

Growth suppression by transforming growth factor beta 1 of human small-cell lung cancer cell lines is associated with expression of the type II receptor

Nine human small-cell lung cancer cell lines were treated with transforming growth factor beta 1 (TGF-beta 1). Seven of the cell lines expressed receptors for transforming growth factor beta (TGF-beta-r) in different combinations between the three human subtypes I, II and III, and two were receptor negative. Growth suppression was induced by TGF-beta 1 exclusively in the five cell lines expressing the type II receptor. For the first time growth suppression by TGF-beta 1 of a cell line expressing the type II receptor without coexpression of the type I receptor is reported. No effect on growth was observed in two cell lines expressing only type III receptor and in TGF-beta-r negative cell lines. In two cell lines expressing all three receptor types, growth suppression was accompanied by morphological changes. To evaluate the possible involvement of the retinoblastoma protein (pRb) in mediating the growth-suppressive effect of TGF-beta 1, the expression of functional pRb, as characterised by nuclear localisation, was examined by immunocytochemistry. Nuclear association of pRb was only seen in two of the five TGF-beta 1-responsive cell lines. These results indicate that in SCLC pRb is not required for mediation of TGF-beta 1-induced growth suppression.

Tetrahymena gene encodes a protein that is homologous with the liver-specific F-antigen and associated with membranes of the Golgi apparatus and transport vesicles

The F-antigen is a prominent liver protein which has been extensively used in studies on natural and induced immunological tolerance. However, its intracellular localization and biological function have remained elusive. It has generally been assumed that the F-antigen is confined phylogenetically to vertebrates. Now we have cloned and characterized a gene from the ciliated protozoan Tetrahymena thermophila encoding a protein which clearly is homologous with the rat F-antigen. The coding region of the Tetrahymena F-antigen (TF-ag) gene specifies a 46,051 M(r) protein and is interrupted by three introns. In accordance with the predicted molecular mass of the TF-ag protein, antibodies raised against a cro-lacZ'-TF-ag fusion protein specifically recognized a 45,000 M(r) protein in Western blots of total T. thermophila protein. Immunoelectron microscopy demonstrated that the TF-ag is associated with membranes of the Golgi apparatus and transport vesicles pointing to a role of TF-ag in membrane trafficking. Transcription of the TF-ag gene, as determined by run-on analyses, was only detectable in growing cells, and following transfer to starvation condition pre-existing TF-ag mRNA was rapidly degraded. The abundance of the TF-ag protein, however, declined only moderately during prolonged periods of starvation demonstrating that extensive release of the TF-ag did not take place. In combination these results suggest that the TF-ag protein is a recycled constituent of the intracellular membrane network in T. thermophila.

Chromatin structure and conserved sequence elements in genes encoding ribosomal proteins in Tetrahymena thermophila

The chromatin structure of the macronuclear genes encoding ribosomal proteins S25 and L1 in the ciliated protozoan Tetrahymena thermophila was analyzed. Using the indirect end-labelling technique, DNase-I-hypersensitive regions were located in the promoter regions as well as in the 3' regions of the genes. The DNase-I-hypersensitive regions were present in chromatin of exponentially growing cells, where the rate of ribosomal-protein gene transcription is high, and in chromatin from starved cells, where transcription of ribosomal-protein genes is severely depressed. Micrococcalnuclease-digestion experiments revealed that the promoter regions of the S25 gene and the L1 gene are devoid of nucleosomes in exponentially growing cells. In starved cells, no nucleosomal organisation of the promoter region of the L1 gene could be detected, whereas nucleosomal structures were discernible in the promoter region of the S25 gene. A conspicuous polypurine sequence motif, AARGGGAAA, is present within or adjacent to the DNase-I-hypersensitive regions in the promoter of the S25 and the L1 gene, and interestingly, the same motif is found also in the promoter regions of the genes encoding ribosomal proteins L21 and L37.

[Transforming growth factor beta. A potent multifunctional growth factor for normal and malignant cells]

The polypeptide growth factor transforming growth factor-beta (TGF-beta) is a multifunctional regulator of basic cellular functions: proliferation, differentiation, cell adhesion and interactions with the extracellular matrix. TGF-beta is part of a regulatory network of which our knowledge is still incomplete, together with other substances such as steroid hormones, oncogene products and integrins. Five isoforms for TGF-beta and five different TGF-beta receptors have been described. TGF-beta exhibits an antiproliferative effect in vitro and in vivo on many cells of epthelial, myeloid, lymphoid and mesenchymal origin together with a growth-stimulating effect on various cells like endothelial cells and epidermal keratinocytes. Production of TGF-beta and receptors for TGF-beta has been found in many cell types, both normal and malignant. Nevertheless the amount of in vivo data is too limited to identify possibilities for therapeutic intervention in the physiological and patophysiological functions of TGF-beta.