Health hazards and electromagnetic fields

Biological rhythms, physical wellbeing and mental states are dependent on our electrical brainwave system interacting with the extremely weak electromagnetic fields generated by the Earth's telluric and Cosmic radiations. In a single generation, since the evolution of humankind over millions of years, we are exposed to a wide range of powerful, artificially generated electromagnetic radiation which adversely affects the subtle balance in nature's energy fields and has become the source of so-called 'diseases of civilization'. This also includes electromagnetic sensitivity. Generally, there is a lack of awareness and understanding of the impact electromagnetic fields can have upon health and wellbeing.Our ancestors were acutely aware that certain locations, were perceived to have a positive energy field which was beneficial to health and vitality. Over time, these areas are now referred to as sacred sites for spiritual ceremony and as healing centres. In contrast, there are other geographical locations that can have a negative effect upon health and these are known as geopathic stress zones. It is believed that such zones can interfere with the brain's normal function that inhibits the release of melatonin and other endocrine secretions needed to replenish the immune system. Geopathic stress can affect animals and plant life as well as human beings and significantly contributes to sick building syndrome (SBS). Whilst there is an increasing body of opinion amongst eminent researchers and scientists who are addressing these issues, the establishment professions are slow to change. However, very gradually, modern allopathic medicine and attitudes are beginning to recognise the extraordinary wisdom and efficacy of ancient traditions such as acupuncture, light, colour and other therapies based on the understanding and treatment of the interaction of a person's electromagnetic subtle body and the immediate environment. These and many other 'complementary' therapies may soon become mainstream medical practice. In the meantime, we can help ourselves by learning how to detect the hazards and daily practise prudent avoidance.

Protein expression of phospholipase C in pregnant and nonpregnant rat uterine tissue

OBJECTIVE

The phosphatidylinositol signaling pathway appears to play a significant role in the intracellular events leading to agonist-stimulated phasic myometrial contractions. The studies described in this report were performed to characterize phospholipase C isoform expression at the protein level and to confirm histologic localization of these proteins within the myometrial smooth muscle layers of the uterus.

METHODS

For these studies, uterine tissue was obtained from timed- pregnant and spontaneously cycling adult female Sprague-Dawley rats. After isolation of myometrial cell membranes and cytosolic proteins, Western blots were performed by using phospholipase C isoform-specific antibodies. Tissue cross-sections of near-term pregnant rat uterus were used with the phospholipase C isoform-specific antibodies for immunohistochemical studies.

RESULTS

The Western blot studies confirmed expression of the phospholipase C-beta3, -gamma1, -gamma2, and -delta1 proteins in both the membrane and cytosolic fractions of rat myometrium; in contrast, only trace amounts of the phospholipase C-beta1 protein was observed in this tissue. The immunohistochemical studies demonstrated localization of the phospholipase C-beta3, -gamma1, -gamma2, -delta1 and to a lesser degree phospholipase C-beta1 isoforms within the longitudinal and circular smooth muscle layers of the near-term pregnant rat uterus.

CONCLUSION

These studies have confirmed the simultaneous expression of several phospholipase C proteins within the smooth muscle cells of the pregnant and nonpregnant rat uterus, thereby providing support for the possible redundant role of these signal transduction enzymes during the generation of cytosolic calcium oscillations and phasic myometrial contractions.

Thrombin-stimulated uterine contractions in the pregnant and nonpregnant rat

OBJECTIVE

Thrombin generated during the active clotting of blood appears to be a potent uterotonic agonist; however, the mechanism underlying this effect on uterine smooth muscle is not well understood. We performed studies to confirm the uterotonic effects of thrombin and to determine whether prostaglandin production plays a role during the uterotonic effects of thrombin or clotting blood.

METHODS

Uterine contraction studies were performed using adult nonpregnant and near-term pregnant rats. The in vitro isometric contraction studies used uterine strips pretreated with indomethacin or vehicle (ethanol), which were then stimulated with thrombin. For the in vivo contraction studies, rats were pretreated with intraperitoneal injections of indomethacin or vehicle (ethanol) then stimulated by intraluminal injection of fresh rat blood or thrombin into the uterus. The contraction data were acquired using isometric force transducers, were computer digitized, normalized for spontaneous activity, and statistically analyzed. Prostaglandin (PG) F2alpha was measured using an enzyme-linked immunoassay.

RESULTS

The in vitro contraction studies demonstrated that both thrombin and actively clotting blood produce a significant increase in the frequency and intensity of uterine contractions. Thrombin stimulation was associated with a 54% increase in PGF2alpha concentration in vitro; indomethacin (1 microM) pretreatment completely inhibited that increase in PGF2alpha production. Despite the suppression of PGF2alpha production, pretreatment with indomethacin had no inhibitory effect on thrombin-stimulated contractile activity. In vivo contraction studies further confirmed that indomethacin (2 mg/kg) pretreatment had no effect on blood- or thrombin-stimulated contractile activity.

CONCLUSIONS

We confirmed that thrombin and thrombin produced by actively clotting blood had a robust uterotonic effect in the rat and that prostaglandin production did not play a significant role in thrombin-stimulated contractions.

Mediation of tubuloglomerular feedback by adenosine: evidence from mice lacking adenosine 1 receptors

Adenosine is a determinant of metabolic control of organ function increasing oxygen supply through the A2 class of adenosine receptors and reducing oxygen demand through A1 adenosine receptors (A1AR). In the kidney, activation of A1AR in afferent glomerular arterioles has been suggested to contribute to tubuloglomerular feedback (TGF), the vasoconstriction elicited by elevations in [NaCl] in the macula densa region of the nephron. To further elucidate the role of A1AR in TGF, we have generated mice in which the entire A1AR coding sequence was deleted by homologous recombination. Homozygous A1AR mutants that do not express A1AR mRNA transcripts and do not respond to A1AR agonists are viable and without gross anatomical abnormalities. Plasma and urinary electrolytes were not different between genotypes. Likewise, arterial blood pressure, heart rates, and glomerular filtration rates were indistinguishable between A1AR(+/+), A1AR(+/-), and A1AR(-/-) mice. TGF responses to an increase in loop of Henle flow rate from 0 to 30 nl/min, whether determined as change of stop flow pressure or early proximal flow rate, were completely abolished in A1AR(-/-) mice (stop flow pressure response, -6.8 +/- 0.55 mmHg and -0.4 +/- 0.2 in A1AR(+/+) and A1AR(-/-) mice; early proximal flow rate response, -3.4 +/- 0.4 nl/min and +0.02 +/- 0.3 nl/min in A1AR(+/+) and A1AR(-/-) mice). Absence of TGF responses in A1AR-deficient mice suggests that adenosine is a required constituent of the juxtaglomerular signaling pathway. A1AR null mutant mice are a promising tool to study the functional role of A1AR in different target tissues.

Translational control is required for the unfolded protein response and in vivo glucose homeostasis

The accumulation of unfolded protein in the endoplasmic reticulum (ER) attenuates protein synthesis initiation through phosphorylation of the alpha subunit of eukaryotic translation initiation factor 2 (eIF2alpha) at Ser51. Subsequently, transcription of genes encoding adaptive functions including the glucose-regulated proteins is induced. We show that eIF2alpha phosphorylation is required for translation attenuation, transcriptional induction, and survival in response to ER stress. Mice with a homozygous mutation at the eIF2alpha phosphorylation site (Ser51Ala) died within 18 hr after birth due to hypoglycemia associated with defective gluconeogenesis. In addition, homozygous mutant embryos and neonates displayed a deficiency in pancreatic beta cells. The results demonstrate that regulation of translation through eIF2alpha phosphorylation is essential for the ER stress response and in vivo glucose homeostasis.

Effects of thrombin on myometrial contractions in vitro and in vivo

OBJECTIVE

A previous report from our laboratory demonstrated that thrombin stimulates myometrial contractions by activating the phosphatidylinositol signaling pathway in a dose-dependent fashion. The studies described in this report sought to determine whether thrombin and blood stimulate myometrial contractions both in vivo and in vitro and whether these uterotonic effects could be suppressed or prevented with thrombin inhibitors.

STUDY DESIGN

In vitro contraction studies were performed with proestrus and estrus rat myometrial tissue. In vivo contraction studies were performed with nonpregnant and timed-pregnant Sprague-Dawley rats.

RESULTS

Pretreatment of thrombin with hirudin suppressed the uterotonic effects of thrombin in vitro. Fresh whole blood stimulated myometrial contractions in a dose-dependent fashion in vitro, and thrombin inhibitors decreased the myometrial response seen with blood alone. Thrombin increased the frequency, intensity, and tone of myometrial contractions in vivo in a dose-related manner. In pregnant animals increasing doses of whole blood increased the frequency and tone of myometrial contractions. In both pregnant and nonpregnant animals whole blood significantly stimulated myometrial contractions, whereas heparinization of the blood significantly suppressed this in vivo uterotonic effect.

CONCLUSION

Thrombin is a potent uterotonic agent both in vitro and in vivo; furthermore, the uterotonic effects of blood appeared to be related to thrombin production during coagulation. These studies provide a possible mechanistic explanation for the observed increase in myometrial contractions in the presence of intrauterine bleeding and may also provide an insight into preterm labor associated with vaginal bleeding.

The mechanisms underlying the stimulatory effects of thrombin on myometrial smooth muscle

OBJECTIVE

The mechanisms underlying the stimulation of uterine contractions in the presence of intrauterine hemorrhage have not been well defined. Thrombin, a blood coagulation factor, activates membrane receptors to result in the stimulation of the phosphatidylinositol signaling pathway and the mobilization of cytosolic calcium in platelets. Our studies sought to determine whether thrombin stimulates similar events in myometrial smooth muscle.

STUDY DESIGN

Cytosolic calcium imaging and in vitro contraction studies were performed with rat myometrial tissue.

RESULTS

At a concentration range of 1 to 100 U/mL thrombin produced phasic myometrial contractions, which were comparable in intensity to those produced by oxytocin and prostaglandin F(2)(alpha). Thrombin-induced cytosolic calcium concentration oscillations were similar to those produced by oxytocin. Contractions stimulated by thrombin were significantly suppressed in response to inhibitors of the phosphatidylinositol signaling pathway. These studies also confirmed that membrane receptor-Gq protein coupling events play a more important role than tyrosine kinase-mediated events during thrombin stimulation of myometrial smooth muscle.

CONCLUSION

Thrombin is a potent uterotonic agonist, and its effects in myometrium are mediated by intracellular signaling events comparable to those activated by classic uterotonic agents. The physiologic importance of thrombin appears to be related to its potential role in the stimulation of uterine contractions in the presence of intrauterine hemorrhage.

Effect of nonviable infants on the infant mortality rate in Philadelphia, 1992

OBJECTIVES

This report measured the effect of births at 22 weeks' gestation or earlier on infant mortality in Philadelphia, Pa.

METHODS

The proportion of live-born deliveries at 22 weeks or earlier was calculated. Overall and race-specific infant mortality was calculated after excluding live-born deliveries at 22 weeks' gestation or earlier.

RESULTS

Of all deliveries, 1.5% were at 22 weeks or earlier. Of these, 68% were stillborn and 32% were live-born. Large hospital-to-hospital variation in the proportion of live-born deliveries at 22 weeks' gestation or earlier was noted. When nonviable births were excluded, overall infant mortality decreased 40%.

CONCLUSIONS

The development of a standardized birth certificate policy is needed and will facilitate comparisons of infant mortality across spatial boundaries and racial/ethnic groups.

The role of diacylglycerol as a modulator of oxytocin-stimulated phasic contractions in myometrium from pregnant and nonpregnant rats

OBJECTIVE

The role of diacylglycerol in the phosphatidylinositol-signaling pathway is to activate protein kinase C. In the myometrium, protein kinase C activation leads to inhibition of phasic contractions. These studies are designed to determine why stimulation of the phosphatidylinositol-signaling pathway caused by oxytocin does not cause a paradoxical suppression of contractions through diacylglycerol production and protein kinase C activation. Specifically, these studies were performed to test the hypothesis that diacylglycerol catabolism is significant in myometrial tissue, thereby precluding its availability for the activation of protein kinase C.

STUDY DESIGN

For these studies, uterine tissue was obtained from Sprague-Dawley rats both nonpregnant and with timed gestations. In vitro contraction studies were performed with cumulative additions of oxytocin (8-64 nmol/L) with and without R59022 (a diacylglycerol kinase inhibitor) or RHC80267 (a diacylglycerol lipase inhibitor). The contraction data were computer-digitalized, analyzed for total contractile activity, normalized for tissue cross-sectional area, and reported as the percentage of spontaneous activity.

RESULTS

In myometrium from nonpregnant animals, inhibition of diacylglycerol lipase with RHC80267 had little effect on oxytocin-stimulated contractile activity, whereas inhibition of diacylglycerol kinase with R59022, although producing an increase in contractile frequency, markedly suppressed total oxytocin-stimulated contractile activity. In contrast, in myometrium from near-term pregnant animals both RHC80267 and R59022 produced marked suppression of oxytocin-stimulated contractile activity.

CONCLUSIONS

These studies have demonstrated that prevention of diacylglycerol degradation, especially in response to inhibition of myometrial diacylglycerol kinase, results in the paradoxic oxytocin-mediated suppression of total myometrial contractile activity. These observations support the hypothesis that, when its catabolism is prevented, diacylglycerol produced in response to stimulation of the phosphatidylinositol-signaling pathway by oxytocin becomes available for protein kinase C activation, resulting in inhibition of myometrial contractile activity.

The effects of 2-aminoethoxydiphenyl borate, a novel inositol 1,4, 5-trisphosphate receptor modulator on myometrial contractions

These studies were performed to evaluate the effect of 2-aminoethoxydiphenyl borate (2-APB), a novel membrane-permeable inositol 1,4,5-trisphosphate-receptor inhibitor on agonist-induced, spontaneous, and KCl-stimulated in vitro myometrial contractions. 2-APB significantly inhibited spontaneous myometrial contractions as well as phasic contractions induced by various uterotonic agonists. Confiriming its effects on intracellular calcium release, 2-APB inhibited phasic contractions in the absence of extracellular calcium. 2-APB had little effect on the tonic response to KCl stimulation, implicating its insignificant effect on voltage-gated calcium channels. The inhibitory effect of 2-APB on phasic contractions was completely reversed by washout. In summary, 2-APB effectively penetrated uterine tissue and significantly inhibited myometrial events previously shown to be mediated through activation of the PI-signaling pathway.

Tissue-specific protein kinase C isoform expression in rat uterine tissue

OBJECTIVE

Activation of the phosphatidylinositol signaling pathway plays a key role during the generation of agonist-stimulated phasic myometrial contractions. Protein kinase C (PKC), a component of this signaling pathway, has been previously shown to produce feedback inhibition of agonist-stimulated myometrial contractions. The studies described in this report were performed to survey the tissue-specific expression of several PKC isoforms in the rat uterus.

METHODS

Uterine tissue was obtained from timed pregnant and normally cycling adult female Sprague-Dawley rats. Immunohistochemical studies were performed using the Vectastain ABC immunostaining technique and PKC isoform-specific polyclonal antibodies. Western blot studies were performed using myometrial tissue separated into cytosol and membrane fractions by differential centrifugation.

RESULTS

These studies confirmed significant expression of the PKC-alpha, -beta 2, -delta, -eta, and -zeta isoforms in myometrium from pregnant and estrus rats, whereas only trace or no expression of the PKC-beta 1, -gamma, -epsilon, and -theta isoforms was observed. Expression of the PKC-alpha, -beta 2, and -eta isoforms decreased modestly during the latter days of gestation; in contrast, PKC-delta and -zeta remained stable during this period. The immunohistochemical studies confirmed expression of the PKC-alpha, -beta 2, -delta, -eta, and -zeta isoforms in both circular and longitudinal smooth-muscle layers of the near-term pregnant rat uterus.

CONCLUSION

In summary, these studies have confirmed significant levels of expression of several isoforms of PKC in estrus and near-term pregnant rat uterine tissue, which was most prominent in the smooth-muscle cells of the myometrium.

Intrauterine gene transfer: gestational stage-specific gene delivery in mice

Intrauterine gene transfer in mice by intraplacental microinjection of recombinant adenoviral or retroviral vectors carrying beta-galactosidase (beta-gal) reporter gene was analyzed in relation to gestational stage, viral titer and promoters. After injections of viral vectors on days 9.5, 11.5 or 14.5 post coitum (p.c.), embryos, fetuses and adult animals were analyzed for beta-gal expression on days 13.5 p.c., 18.5 p.c. and at 2 months of age, respectively. Injection of adenoviral vectors on day 9.5 or day 11.5 p.c. resulted in high beta-gal expression in the heart or liver, respectively. Injection on either day also gave expression in other tissues including vasculature and hindbrain. This temporal pattern of adenoviral transduction correlated with the expression level of integrin beta3 subunit, which is known to be a component involved in adenoviral transduction. Adenovirus-mediated intrauterine gene transfer resulted in persistent beta-gal expression in multiple cell foci in the liver and hearts of 2-month-old adult animals treated in utero, indicating stable integration of the transgene into the host cell genome at a low frequency. Although at low efficiency, injection of retroviral vector on day 9.5 and 11.5 p.c. resulted in beta-gal expression in embryonic liver, while day 9.5 p.c. injection resulted in persistent beta-gal expression in 2-month-old adult heart. This is the first study to show gestational stage-specific gene transfer via intraplacental microinjection of adenoviral vectors.

Tyrosine kinase-mediated activation of cytosolic calcium oscillations and phasic myometrial contractions

These studies sought to test the hypothesis that tyrosine kinase-stimulated phasic myometrial contractions are mediated by activation of the phosphatidylinositol (PI)-signaling pathway and the generation of cytosolic calcium oscillations. For these studies, uterine tissue was obtained from adult female Sprague-Dawley white rats during the proestrus/estrus phase of the cycle. In vitro contraction studies were performed using pervanadate (a tyrosine phosphatase inhibitor) with and without inhibitors of the PI-signaling pathway, including 2-nitro-4-carboxyphenyl-N,N-diphenylcarbamate (a phospholipase C inhibitor), thimerosal (an inositol-trisphosphate receptor/channel inhibitor), and Ruthenium red (a ryanodine receptor inhibitor), and with oxytocin or prostaglandin F2 alpha (two classic uterotonic agonists). Cytosolic calcium studies were performed using Fura-2-loaded myometrial strips. During these studies, pervanadate was observed to produce cytosolic calcium oscillations and phasic contractions in myometrial tissue comparable to those produced in response to oxytocin and prostaglandin F2 alpha. The pervanadate-stimulated phasic contractions were significantly suppressed in response to inhibition of phospholipase C, the inositol-trisphosphate receptor, and the ryanodine receptor, thereby confirming the importance of the PI-signaling pathway during tyrosine kinase-associated myometrial activity. Further confirming the important and shared role for the PI-signaling pathway during pervanadate-stimulated myometrial contractions, no significant additive effects were observed when classic uterotonic agonists such as oxytocin or prostaglandin F2 alpha were combined with pervanadate.

5-fluoro-2-methyl-N-[5-(5H-pyrrolo[2,1-c][1,4]benzodiazepine-10(11H)-yl carbonyl)-2-pyridinyl]benzamide (CL-385004) and analogs as orally active arginine vasopressin receptor antagonists

Synthesis and structure-activity relationships (SAR) of orally active arginine vasopressin (AVP) receptor antagonists are discussed. Potent and orally active AVP receptor antagonists are produced when ring A of VPA-985 (1) is replaced with a 3-pyridinyl unit (2b).

4,10-dihydro-5H-thieno[3,2-c][1]benzazepine derivatives and 9,10-dihydro-4H-thieno[2,3-c][1]benzazepine derivatives as orally active arginine vasopressin receptor antagonists

Synthesis and structure-activity relationships (SAR) of arginine vasopressin receptor (AVP) antagonists are described. Potent and orally active compounds are prepared when tricyclic 10,11-dihydro-5H-pyrrolo[2,1-c][1,4]benzodiazepine moiety in VPA-985 1 is replaced with a compound 7 or 12.

Lowering the language barrier in an acute psychiatric setting

OBJECTIVES

The aim of this paper is to investigate the effectiveness of a training and policy strategy to improve communication opportunities in an acute inpatient unit for patients of non-English-speaking background (NESB) with low English proficiency.

METHOD

A pre- and post-intervention design involved: (i) a survey of the multilingual skills of 80 clinical staff; (ii) recording of patients' ethnic background and proficiency; (iii) pre- and post-intervention data collection of the main outcome measure (communications with patients in a language other than English [LOTE]); and (iv) staff training, and active encouragement, in interpreter use. English proficiency was assessed using the population census proficiency question.

RESULTS

Of 257 admissions, 33% were of NESB and 19% preferred to speak a LOTE. The staff survey yielded a 49% return rate and showed that, of 11 LOTEs spoken by patients, seven were also spoken by 17 of the staff. Twenty-nine percent of staff were not clinically proficient in these languages. Compared to the NESB population, a higher proportion of NESB patients rated low on proficiency. Following the intervention, interpreter bookings and booking duration increased significantly.

CONCLUSIONS

A standard training package and a policy promoting interpreter use improved communication opportunities in an acute setting where language needs are typically poorly met. Failure to ensure effective communicate raises risks of misdiagnosis and inappropriate treatment. By measuring patients' proficiency directly, the present study identified a higher level of need for interpreter services than estimated by past reports.

The effect of stress inoculation training on anxiety and performance

Stress inoculation training is an intervention that has shown considerable promise; however, many questions arise regarding the application of this clinically based approach to more applied workplace settings. A meta-analysis was conducted to determine the overall effectiveness of stress inoculation training and to identify conditions that may moderate the effectiveness of this approach. The analysis was based on a total of 37 studies with 70 separate hypothesis tests, representing the behavior of 1,837 participants. Results indicated that stress inoculation training was an effective means for reducing performance anxiety, reducing state anxiety, and enhancing performance under stress. Furthermore, the examination of moderators such as the experience of the trainer, the type of setting in which training was implemented, and the type of trainee population revealed no significant limitations on the application of stress inoculation training to applied training environments.

Intracellular mechanisms underlying prostaglandin F2alpha-stimulated phasic myometrial contractions

These studies sought to test the hypothesis that prostaglandin F2alpha (PGF2alpha)-stimulated phasic myometrial contractions are characterized by the activation of the phosphatidylinositol-signaling pathway resulting in the generation of cytosolic calcium oscillations. For the experiments described in this report rat myometrial tissue was used, after the tissue was loaded with fura 2, to perform cytosolic calcium imaging studies and to perform computer-digitalized in vitro isometric contraction studies. Consistent with the above hypothesis, the cytosolic calcium-imaging studies demonstrated PGF2alpha-stimulated cytosolic calcium oscillations occurring simultaneously with phasic contractions. The in vitro isometric contraction studies confirmed that previously reported inhibitors of the phosphatidylinositol-signaling pathway and cytosolic calcium oscillation mechanisms resulted in significant inhibition of PGF2alpha-stimulated phasic myometrial contractions. In summary, these studies have provided substantial support for the hypothesis that PGF2alpha-stimulated phasic myometrial contractions are generated by intracellular signaling mechanisms involving activation of the phosphatidylinositol-signaling pathway and the production of cytosolic calcium oscillation-like phenomena.

Gq-protein alpha subunit expression and distribution in pregnant rat myometrial tissues

OBJECTIVE

Multiple G-protein isoforms play an integral role in signal transduction; the Gq subtype of G-protein alpha subunits is involved in the activation of the phosphatidylinositol signaling pathway. The studies described herein evaluate the expression of Gq, along with Gs and Gi, in pregnant and nonpregnant rat myometrial tissues.

METHODS

Myometrium and other tissues were obtained from nonpregnant and timed-pregnant Sprague-Dawley rats. Western blot studies were performed using polyclonal G-protein isoform-specific antibodies. Immunohistochemical studies were performed using the same antibodies with specimens of myometrium, intestine, and skeletal muscle.

RESULTS

The Western blot studies confirmed differential expression of all types of G-protein alpha subunit subtypes in rat myometrial tissues. In pregnant rat myometrium, the expression of Gq and Gs was sustained through day 22, whereas, Gi expression decreased on day 20 and remained low through the remainder of gestation. The immunohistochemical studies revealed significant staining for Gq and Gs in the myometrial layers of the pregnant and nonpregnant rat uterus; in contrast, immunostaining for Gi was minimal in nonpregnant myometrium, and even lower in myometrium from pregnant uteri.

CONCLUSIONS

These studies have confirmed expression of the Gq, Gi, and Gs alpha subunits in rat myometrial tissue. Immunohistochemistry confirmed that Gq was expressed at high levels in the myometrial layer of the pregnant and nonpregnant uterus. These observations support the hypothesis that Gq expression is critically important for the transduction of hormone signals, such as those responsible for the generation of phasic myometrial contractions.

Beta-adrenergic receptor subtype gene expression in timed-pregnant rat myometrium

OBJECTIVE

Classic radioligand binding techniques have suggested that beta 1- and beta 2-adrenergic receptor subtype proteins are expressed in myometrial tissue; however, to date these observations have not been confirmed at the level of the messenger ribonucleic acid for these clinically important membrane receptors. The studies described in this report sought to use quantitative reverse transcriptase-polymerase chain reaction techniques to confirm expression of messenger ribonucleic acid for the beta 1- and beta 2-adrenergic receptors in myometrial tissue and to determine whether messenger ribonucleic acid expression for these two adrenergic receptors is modulated during pregnancy.

STUDY DESIGN

For these studies total cellular ribonucleic acid was isolated from myometrial tissue obtained from timed-pregnant Sprague-Dawley rats by the guanidium thiocyanate-phenol-chloroform extraction technique; formaldehyde-agarose gels then confirmed isolation of intact ribonucleic acid. Random hexamers and reverse transcriptase were used to synthesize complementary deoxyribonucleic acid. Subsequently, polymerase chain reaction was performed with subtype specific 20-mer sense and antisense oligonucleotide primers specific for the rat beta 1- and beta 2-adrenergic receptors. Inclusion of internal standard deoxyribonucleic acid sequences allowed quantification of the reverse transcriptase-polymerase chain reaction results.

RESULTS

By use of total cellular ribonucleic acid isolated from myometrial tissue, reverse transcriptase-polymerase chain reaction generated the expected 328 bp product for the beta 1-receptor and the expected 559 bp product for the beta 2-receptor along with internal standard deoxyribonucleic acid sequences for both. The identity of the beta 1- and beta 2-adrenergic receptor polymerase chain reaction products was confirmed on the basis of restriction endonuclease digestions producing the expected deoxyribonucleic acid fragments and by Southern blots using beta 1- and beta 2-adrenergic receptor-specific complementary deoxyribonucleic acid probes. The reverse transcriptase-polymerase chain reaction studies confirmed a gradual decline in beta 1-receptor messenger ribonucleic acid and stable expression of beta 2-receptor messenger ribonucleic acid during the second half of gestation in pregnant rat myometrial tissue.

CONCLUSIONS

In summary, these studies have confirmed, at the messenger ribonucleic acid level, expression of the beta 1- and beta 2-adrenergic receptor subtypes in timed-pregnant rat myometrial tissue.

The mechanisms underlying Bay K 8644-stimulated phasic myometrial contractions

OBJECTIVE

Phasic myometrial contractions appear to be produced by calcium transients resulting from the activation of the phosphatidylinositol-signaling pathway. Bay K 8644, an L-type calcium channel activator, produces an increase in frequency and intensity of phasic myometrial contractions. These studies were performed to test the hypothesis that Bay K 8644-stimulated contractions were mediated through mechanisms involving phosphoinositide-specific phospholipase C activation and cytosolic calcium oscillation-like mechanisms.

METHODS

In vitro contraction studies and intracellular calcium imaging were performed on longitudinal strips of uterine tissue obtained from mature virgin Sprague-Dawley rats. Isometric contraction data were computer digitized, analyzed for contraction area, and normalized for cross-sectional area. Dose-response studies were performed using previously reported inhibitors of cytosolic calcium oscillation mechanisms. In addition, qualitative inositol-phosphate production studies were performed after prelabeling uterine tissue in vitro with 3H-inositol. Subsequently, the labeled inositol phosphates were separated and recovered using anion exchange chromatography.

RESULTS

Bay K 8644 produced periodic calcium transients or oscillations along with a dose-related increase in contractile activity and a significant increase in inositol-phosphate production. In contrast, neomycin (an inhibitor of phospholipase C), adenine (an inhibitor of calcium-induced calcium release), nifedipine (an L-type calcium channel blocker), and EGTA (a calcium chelator) significantly inhibited Bay K 8644-stimulated contractile activity.

CONCLUSIONS

These results are consistent with the hypothesis that Bay K 8644, through its facilitation of increased intracellular calcium, results in the activation of the phosphatidylinsitol-signaling pathway and cytosolic calcium oscillation-like phenomena, thereby resulting in the generation of phasic myometrial contractions.

The effect of stress inoculation training on anxiety and performance

Stress inoculation training is an intervention that has shown considerable promise; however, many questions arise regarding the application of this clinically based approach to more applied workplace settings. A meta-analysis was conducted to determine the overall effectiveness of stress inoculation training and to identify conditions that may moderate the effectiveness of this approach. The analysis was based on a total of 37 studies with 70 separate hypothesis tests, representing the behavior of 1,837 participants. Results indicated that stress inoculation training was an effective means for reducing performance anxiety, reducing state anxiety, and enhancing performance under stress. Furthermore, the examination of moderators such as the experience of the trainer, the type of setting in which training was implemented, and the type of trainee population revealed no significant limitations on the application of stress inoculation training to applied training environments.

Ionomycin-stimulated phasic myometrial contractions

Ionomycin, a calcium ionophore, facilitates the sustained entry of extracellular calcium; however, in myometrial tissue it stimulates phasic contractions. This study sought to define further this unanticipated effect of ionomycin and to begin to explore the possible mechanism(s) involved. Utilizing rat uterine strips, in vitro isometric contraction studies were performed to determine the effects of ionomycin with and without membrane-permeant inhibitors of cytosolic calcium oscillations. To determine the effects of ionomycin on phospholipase C, qualitative inositol phosphate production studies were performed. The in vitro contraction studies confirmed that ionomycin-stimulated phasic myometrial contractions were potentially dependent on stimulation of phospholipase C, calcium-induced calcium release, and additional calcium influx through dihydropyridine-sensitive membrane calcium channels. The inositol phosphate production studies confirmed that ionomycin stimulated phospholipase C in a dose-related fashion to levels comparable to oxytocin. In summary, these observations have confirmed the ability of ionomycin to generate dose-related phasic myometrial contractions through mechanisms potentially involving the phosphatidylinositol-signaling pathway.

Effects of 2,5-di(tert-butyl)-1,4-hydroquinone, an endoplasmic reticulum Ca(2+)-ATPase inhibitor, on agonist-stimulated phasic myometrial contractions

Phasic myometrial contractions utilize mechanisms involving the cycling of calcium into and out of intracellular calcium stores. These studies were performed to determine the effects of 2,5-di(tert-butyl)-1,4-hydroquinone (tBHQ), an endoplasmic reticulum Ca(2+)-ATPase inhibitor, on in vitro isometric myometrial contractions. These studies demonstrated that low concentrations of tBHQ (eg. 10 microM) appear to inhibit intracellular calcium cycling, whereas higher concentrations also inhibit extracellular calcium influx. These combined tBHQ effects markedly suppressed myometrial contractions stimulated in response to various agonists including oxytocin, PGF2 alpha, KCl, ionomycin, and Bay K 8644.

A rheumatoid factor transgenic mouse model of autoantibody regulation

To address whether B cells expressing a disease-associated autospecificity are regulated in normal mice, we have established a rheumatoid factor (RF) transgenic model of autoimmunity, using V genes derived from an IgA anti-IgG2a RF isolated from an autoimmune MRL/lpr mouse. As we wished to study induction of tolerance during B cell development, we cloned the VH gene into an IgM expression vector. The RF we chose binds only IgG2a of the 'a' allotype (IgG2a) but not IgG2ab allowing us to produce transgenic animals on IgHa and IgHb backgrounds, which either express or lack the self-antigen. Two transgenic lines were studied. Using mice which lack the self-antigen, we show by fluorescence activated cell sorting and hybridoma analysis that the H and L transgenes are expressed to the exclusion of endogenous genes in most splenic B cells. In spite of good allelic exclusion, transgenic mice which are genetically capable of expressing IgG2aa have reduced but significant (approximately 50 micrograms/ml) serum levels. Nonetheless, the frequency and numbers of transgene-expressing B cells in peripheral lymphoid organs of such mice which have the self-antigen are similar to those which lack it (IgHb mice). Thus, B cells expressing an anti-self IgG2a surface receptor can develop in this system. Whether such B cells are anergic or otherwise regulated in autoantigen-expressing mice is discussed.