Resting membrane state as an interplay of electrogenic transporters with various pumps.

In this study, a new idea that electrogenic transporters determine cell resting state is presented. The previous assumption was that pumps, especially the sodium one, determine it. The latter meets difficulties, because it violates the law of conservation of energy; also a significant deficit of pump activity is reported. The amount of energy carried by a single ATP molecule reflects the potential of the inner mitochondrial membrane, which is about -200 mV. If pumps enforce a resting membrane potential that is more than twice smaller, then the majority of energy stored in ATP would be dissipated by each pump turning. However, this problem could be solved if control is transferred from pumps to something else, e.g., electrogenic transporters. Then pumps would transfer the energy to the ionic gradient without losses, while the cell surface membrane potential would be associated with the reversal potential of some electrogenic transporters. A minimal scheme of this type would include a sodium-calcium exchanger as well as sodium and calcium pumps. However, note that calcium channels and pumps are positioned along both intracellular organelles and the surface membrane. Therefore, the above-mentioned scheme would involve them as well as possible intercellular communications. Such schemes where various kinds of pumps are assumed to work in parallel may explain, to a great extent, the slow turning rate of the individual members. Interaction of pumps and transporters positioned at distant biological membranes with various forms of energy transfer between them may thus result in hypoxic/reperfusion injury, different kinds of muscle fatigue, and nerve-glia interactions.

An approach to expand description of the pump and co-transporter steady-state current.

The membrane transporters (pumps and co-transporters) are the main players in maintaining the cell homeostasis. Models of various types, each with their own drawbacks, describe transporter behavior. The aim of this study is to find the link between the biophysically based and empirical models to face and solve their specific problems. Instead of decreasing the number of states and using few complex rate constants as is usually done, we use the number of states as great as possible. Then, each transition in the cycle can represent an elementary process and we can apply the mass action law, according to which if rate constants depend on concentrations the dependence is linear. Thus, the expression for the steady state transporter current can be transformed from a function of rate constants into a function of concentrations. When transporter states form a single cycle, it can be characterized by two modes of action - forward and backward ones. Specific mode is realized depending on the available free energy. Each mode of action is characterized by a set of transporter affinities together with a parameter that describes the maximal turning rate. Except standard affinities corresponding to the substances that are binding to the transporter, affinities for the substances that are released are also defined. Such scheme provides great possibilities to construct approximations as each individual affinity could be estimated from experiments as precisely as possible. The approximations may be used for not only description and study of the transporter current but also in cellular models that attempt to describe wide variety of processes in excitable cells.

Adaptive optics in spinning disk microscopy: improved contrast and brightness by a simple and fast method.

Multiconfocal microscopy gives a good compromise between fast imaging and reasonable resolution. However, the low intensity of live fluorescent emitters is a major limitation to this technique. Aberrations induced by the optical setup, especially the mismatch of the refractive index and the biological sample itself, distort the point spread function and further reduce the amount of detected photons. Altogether, this leads to impaired image quality, preventing accurate analysis of molecular processes in biological samples and imaging deep in the sample. The amount of detected fluorescence can be improved with adaptive optics. Here, we used a compact adaptive optics module (adaptive optics box for sectioning optical microscopy), which was specifically designed for spinning disk confocal microscopy. The module overcomes undesired anomalies by correcting for most of the aberrations in confocal imaging. Existing aberration detection methods require prior illumination, which bleaches the sample. To avoid multiple exposures of the sample, we established an experimental model describing the depth dependence of major aberrations. This model allows us to correct for those aberrations when performing a z-stack, gradually increasing the amplitude of the correction with depth. It does not require illumination of the sample for aberration detection, thus minimizing photobleaching and phototoxicity. With this model, we improved both signal-to-background ratio and image contrast. Here, we present comparative studies on a variety of biological samples.

[MANAGEMENT OF PLACENTA ACCRETA, DIAGNOSED BEFORE BIRTH].

The optimal management of placenta accreta and until now remains unclear. The reasons for this are a rarity of this condition and the considerable heterogeneity of the group under the term "placenta accreta." Total hysterectomy during caesarean section is the most common approach to a known placenta accreta. Planned or emergency perinatal hysterectomy is associated with several complications--damage to the urinary tract, relaparotomiya, massive blood transfusions and stay in ICU. The average blood loss is about 3000 ml. To reduce blood loss in perinatal hysterectomy contribute: preliminary uterine artery occlusion, istmus-coporal longitudinal hysterectomy for extraction of the fetus, placental extraction along with the uterus. To save the woman's uterus at placenta accreta are using the following methods: cutting the uterine wall on which is located the placenta, imposing single stitches covering 2-3 cm in 1 cm, around the placental area; removal of the maximum possible part of the placenta; using longitudinal hysterectomy. So far, there are no comparative studies of the efficacy of different surgical techniques to preserve the uterus cases of placenta accreta. Extraction of the placenta to be done after the administration of uterotonics and devascularization the uterus. To reduce bleeding from the uterus after removal of parts of the placenta and according to the situation can be used: x-back hemostatic sutures from internal side of the uterus, tamponade with gauze roll, balloon catheters or haemostatic mushrooms. Conservative surgical treatment of placenta accreta is not always possible. In hospital Maternity Hospital-Sofia for the period 1986-2000 there were 17 cases of placenta accreta diagnosed only at birth. Maintaining the uterus was successful in 35% of these cases.

[Macroscopic and histopathological changes in the fetal appendages as a factor in the pathogenesis of intrauterine fetal death ].

BACKGROUND: Intrauterine fetal death is an agonizing, often unpredictable event. Autopsies of stillborn fetuses, including placentas, umbilical cord and fetal membranes, are performed to clarify the cause of death. Autopsy results are not always easily understood by the patients and difficult to clarify by the specialists. OBJECTIVE: To evaluate the macroscopic pathological and histopathological changes in placenta, umbilical cord and fetal membranes as a factor in the pathogenesis of intrauterine fetal death. MATERIALS AND METHODS: Retrospective review of 129 autopsy reports of singleton stillborn fetuses and placentas from 23 to 41 weeks of gestation. RESULTS: Macroscopic and histopathological findings in the placenta, often in combination with inflammatory changes prevailing in premature cases, while macroscopic and histopathological findings in umbilical cord predominate in term stillborn. In 11% of cases there were no specific pathological findings. CONCLUSIONS: Pathological analysis of the placenta is essential for clarifying the pathogenesis of stillbirths. Simplifying the classification of pathological results of fetal appendages at autopsy categories--changes in the placenta, changes in the umbilical cord and inflammatory changes may contribute to easier interpretation and allows for comparison of results.

[PROLONGED RETAINED PLACENTA ACCRETA IN THE UTERUS AFTER VAGINAL DELIVERY (A CASE REPORT AND REVIEW OF LITERATURE)].

A case of prolonged retention in the uterus of placenta accreta after vaginal delivery is reported in the paper. The patient was 20 years old G3, P0 with two pregnancy terminations on request. She was admitted to the obstetric department of a regional hospital one day after the EDD with irregular contractions and non reassuring CTG. A few hours later intrauterine fetal demise occurred. Spontaneous labor commenced and a stillborn growth retarded fetus was delivered. Methergin was administered during the third stage of labor, but the placenta was not separated even after repeated Crede maneuvers, the last one under anesthesia. Since cervical spasm was present, the attempts for manual or instrumental separation of the placenta were unsuccessful. There was no genital bleeding, so further conservative approach was followed including continuous IV infusion of uterotonics, combined antibiotic therapy, close observation of the vital signs and the laboratory indicators. Three days after delivery the patient was transferred to a University Hospital because of subfebrile temperature. Her general condition on admission, although subfebrile, was good, there was no genital bleeding, the cervix was closed. The subfebrile temperatrure persisted despite antibiotic treatment; CRP was elevated (51,9 mg/l.). Because of suspicion for endomyometritis, on day 8th after delivery instrumental extraction of the placenta was undertaken with preparedness for hysterectomy in case of need. Although the procedure was difficult, with the placenta being extracted in parts, bleeding was scarce. The post operative period was uneventful and the patient was discharged from hospital five days after the intervention. A review of literature on the obstetric management of cases with retained placenta accreta after vaginal delivery is presented. The existing therapeutic options are discussed including their advantages and complications.

[Case of intrauterine retardation and fetal death during labor].

The case concerns to a 37 years old pregnant woman with a history of three miscarriages. Ultrasound biometry in early pregnancy corresponds to the term calculated according the last menstrual period (LMP). At 37 week of gestation was determined retardation of 5 weeks. Doppler velocimetry and quantity of amniotic fluid were in normal ranges and the pregnant refused hospitalization. She was admitted to the hospital three days after the appointed term without uterine contractions. The fetal ultrasound biometry meets 33 weeks and the Doppler examination of a. umbilicalis found resistance index (RI) of the upper limit of normal. The cardiotocography record shows: baseline fetal heart rate--143 beats/min, good variability and reactivity. There was one deceleration for 3 minutes, and then the recording returns to normal. Re-monitoring after 30 minutes establishes of a periodic decelerations and a tendency to bradycardia with reserved variability. At the start of the emergency Cesarean Section fetal heart beats are single. The delivered babe was with Apgar O. The reanimation was not successful and the fetus died. From the autopsy signs of severe asphyxia. In conclusion, it can be assumed that in strongly retarded fetuses, cardiotocography recording and Doppler velosimetry are not sufficiently reliable methods for continued monitoring. In late-onset and severe intrauterine growth retardation (IUGR) desirable delivery time is after reaching biological maturity at 36-37 week.

[Causes of stillbirths according to the period of pregnancy].

INTRODUCTION: Stillbirths represent 50% of all perinatal mortality and remain significant and unanswered problem. OBJECTIVE: To investigate the causes of stillbirths in term and preterm fetuses and place of intrauterine growth retardation in the pathogenesis of antenatal death. MATERIALS AND METHODS: The study was retrospective for the period 2008 to 2013, covers 217 cases of stillbirths in University Hospital "Maichin dom" Sofia. Gestational age was from 23 to 41 weeks. Inclusion criteria for the study were: antenatal occurred dead and singleton pregnancy. Exclusion criteria: fetal malformations and multiple pregnancies. Thus number of enrolled cases was 153. RESULTS: The causes of stillbirths are different in different groups according gestational age. The cases of unknown cause, abruption of placenta and preeclampsia prevail in preterm group. The term stillborns headed with pathology of the umbilical cord, followed by cases of unknown cause, diabetes and infection. Overall, preterm group stillborn with mass below 10 percentile for the gestational age - 53 % predominate, compared with those born at term - 39%. CONCLUSIONS: The incidence of stillbirths is higher in preterm than term born fetuses. The causes of antenatal death in preterm is mainly abruption of placenta and preeclampsia, whereas in term - pathology of the umbilical cord. In premature stillborn intrauterine growth retardation is more common in comparison with those on term. Unexplained antenatal fetal death is more common in preterm fetuses.

[Fetal growth curve based on gestational age and fetal maturity].

Most of the fetal growth charts available in the literature were created too long ago, based on various populations and using various eligibility criteria. The purpose of our study was to develop a nomogram of fetal weights based on the gestational age and neonatal maturity. The study is prospective and retrospective in nature. 1,748 fetuses of 20 to 40 gestational weeks were assessed directly after birth, and all cases were classified based on the number of weeks of pregnancy completed, but fetuses were not classified based on their gender. The mean weekly weight gain of fetuses was 100 g until the 30 gestation week, and 200 g thereafter. The results we obtained for the 50th percentile for fetus weight were weights meanly 200 g lower than those per Babson's chart (Fenton's scale). The weights in the 10th percentile were also 50-100 g lower until the 31 gestation week, with increasing difference to 150 g thereafter. For 2011, the incidence of growth-retarded fetuses at Maichin Dom Hospital was 7.09% per Babson's chart, and 5.1% according to our data of the 10th percentile. The study demonstrated that nomograms for relevant populations should be used to assess normal growth of fetuses.

[Intraamniotic infection--cause and satellite of preterm birth].

Intraamniotic infection (IAI), most commonly presented as chorioamniotitis, plays a major role in the pathogenesis of preterm birth (PTB). In this study, we sought for signs of IAI through clinical and laboratory parameters (leukocyte count, CRP concentration and IL-6 in maternal blood), and compared those to the newborns' infectious condition. Using cervical and vaginal secretion cultures, we determined the probable causing agents of IAI. We also followed up the therapeutic effect from the use of corticosteroids, tocolitics and antibiotics for the treatment of PTB. The results demonstrated that over 46% of the pregnant women with PTB presented with evidence of IAI. The best diagnostic option to detect an IAI provides maternal blood IL-6, and the combination between leukocyte count and CRP is a must for routine examinations. We did not isolate a single vaginal pathogen but a combination of harmful microbes which provided evidence of a vaginal ecosystem disorder. The combination therapy in over 50% of women had a positive effect on PTB for the period of corticosteroid prophylaxis (72 hrs). From hour 84, antibiotic therapy can no longer control IAI development.

[A case of cervical myoma and pregnancy].

We are presenting a case of women in 31 gestational week of her pregnancy with prematurely ruptured membranes and 10.5 cm myoma in the vagina. The cervix was elevated with well-defined external orifice, dilated to 10.5 cm. C-section with myomectomy was performed. The myoma had penetrated in the vagina with a lot of adhesions to the rectum and cavum Douglais. The vaginal vault and the posterior cervical wall were restored with single sutures. Smooth postoperative period.

[Role of IL-6 for the diagnosis of preterm birth].

The preterm birth (PTB) is still a problem for the modern obstetrics, with certainly unsolved questions. Mainly this is associated with the lack of chance to decrease its frequency but also due to the tendency of definite change of its structure--high level of extreme premature state. Intra uterus infection (IUI) is one of the major etiologic reasons for PTB. The early detection of IUI and the determination of the level of fetus damage are the leading therapeutic approach to PTB. The present study includes the test reliability of interleukin-6 (IL-6) to diagnose IUI and early neonatal infectivity. The groups of patients are (A) pregnant women with regular term and (B) pregnant women with PTB, both, with ruptured amniotic membrane or with intact ones. The results of their infectious parameters are determined and analyzed: Leu number, CRP and IL-6 in mother's blood and newborn's blood. It is obvious that the highest percent of IUI is detected by using the blood level of IL-6, followed by CRP and Leu number. The most significant correlation is established between PTB and pathologic levels of IL-6 in cord blood (> or = 30 pg/ml, OR-40.09). In conclusion, we could summarize that IL-6 is a reliable parameter and sign for IUI in cases with PTB. It opens the door to a potential application of its laboratory testing, thus allowing a crucial decision with problematic therapeutic cases, when discussing the PTB.

[The very low birth weight and very low gestational age neonates--survival, prognosis and perspectives].

The advances in perinatal medicine during the last decades lead to a reduction in neonatal mortality rates in risk newborns and a gradual lowering of the gestational age when survival is possible to 22 weeks of gestation. In the present survey we are making a review of the studies about the survival and the prognosis in neonates with very low birth weight and gestational age (VLBW, VLGA). Infants weighting more than 1000 g and with gestational age above 28 g.w. are with a good prognosis: low neonatal mortality and morbidity rates. In newborns with gestational age between 26 and 28 g.w. the neonatal mortality rates are relatively low, however the trend of further lowering has not changed during the last 15 years; morbidity rates varies between different centers and are relatively high. The greatest medical, social and ethical dilemmas represent the newborns with gestational age less than 25 g.w. In this group with an overall high neonatal mortality (with big variations between different centers), there is a significant high morbidity rate among survived babies. These are the infants at the border of perinatal viability, the "grey zone" of the neonatology, where further discussions are going on about the activity of the obstetric management, the intensity and the amount of neonatal resuscitation.

[Indications for vaginal delivery with forceps application].

UNLABELLED: The aim of the study was to establish indications for operative vaginal delivery by extraction of the fetus with forceps in modern obstetrics. MATERIAL AND METHODS: This is a retro- and prospective study which includes 672 forceps deliveries in the period of 1994-2008 in Maternity hospital Sofia. Simpson and Kielland were used for extractions subject to appropriate indications and conditions, regardless of the gestational week of pregnancy. RESULTS: The most frequent indication for forceps application is fetal asphyxia (78.1%) and considering the frequency for 15 years it is the permanent, leading indication for forceps in modern obstetrics. Arrest of the head in the same plane of the pelvis was the indication in 23.6% of the cases it varies and is rarely primary through the 15 year period. Ineffective uterine contractions and/or pushes (16.7%) tends to decrease its frequency. Avoiding maternal efforts in the second stage of labor (8.5%) and in 50% of the cases was indicated for women with cardiovascular diseases. Malpositions (7.7%) increases through the years probably secondary to epidural analgesia. Indication preeclampsia-eclampsia is described in 1.3% of cases, followed by genital bleeding by 1.9% and prolapse of the umbilical cord by 0.6% and they are more incidentally reasons for application of forceps. CONCLUSION: Asphyxia of the fetus is the most common and a leading indication for extraction of the fetus with forceps. Ineffective uterine contractions and the arrest of the head in the same plane of the pelvis are consistent in their occurrence and lead to prolonged labor. In certain critical conditions (genital bleeding, prolapse of the umbilical cord and eclampsia) extraction of the fetus with forceps remains the only way for fast vaginal delivery.

[Susceptibility to antibiotics of microorganisms related with recurrent bacterial vaginosis].

There are presented data of sensitivity to a range of antibiotics of the main microorganisms related with the problem "recurrent bacterial vaginosis". G. vaginalis are sensitive in 34% to metronidazole, and 82% to clindamycin. Atopobium spp. and HP/+/Lactobacillus spp. are resistant to metronidazole and sensitive to clindamycin.

[Frequency and characteristics for forceps delivery].

AIM: To establish the incidence of vaginal operative deliveries by extraction of the fetus with forceps and the degree of prematurity of newborns in which it is applied, to specify the type of forceps which is imposed. MATERIAL AND METHODS: The study included 672 births, completed by extraction of the fetus with forceps in the period 1994-2008 year in University hospital "Maichin dom" Sofia. The total number of births was 47,130, of which 32,924 have become per vias naturalis. Age of birth was from 13 to 42 years. The study was done prospectively and retrospectively. RESULTS: The incidence of forceps extraction of the total number of births for the period is 1.43%, as seen following the trend - in the first years of the period 1994 - 1995 is more than 2% of total births, in the period 1996 to 2003 years and then fluctuated between 1 and 2%, and after 2004 has decreased below 1%. There could be noticed slight and gradual reduction in the incidence of operative vaginal delivery by forceps. The general incidence of forceps extraction compared to vaginal births was 2.04% for the entire period, at the beginning is 3.5% and then fell between 2.5 and 2% for the period 1995 to 2003 years, then in 2004 was between 1 and 2%. In 94.8% of cases forceps was applied to term fetuses and 5.2% of cases in preterm fetuses (respectively 3.78% in premature fetuses 1-st degree, 1.10 percent premature fetuses II-nd degree and 0.31% in premature fetuses III-grade). In 74.65% of the cases was outlet forceps and 25.35% was low forceps. CONCLUSIONS: Forceps remains an irreplaceable tool for operative vaginal birth, but there is a tendency to reduce its use. In preterm fetuses forceps is the only method for vaginal operative delivery. Today only outlet and low forceps have their role in modern obstetrics, but there is a trend to reduce the incidence of the rotational forceps in comparison to increase of the use of outlet forceps.

[Some aspects of maternal mortality in Bulgaria].

The author discusses the world and bulgarian maternal mortality rates and suggests the creation of obligatory diagnostical and therapeutical guidelines in urgent obstetrical cases.

[Neonatal dead and method of delivery < or = 32 weeks of gestation].

UNLABELLED: The purpose of this study is to determine the dependence of neonatal dead by method of delivery at prematurity. MATERIAL AND METHODS: Prospective study on 238 single births from 25-32 g.w. According to the method of delivery and fetal presentation newborns are divided into the following groups: vertex presentation - vaginal birth (PN) and Cesarean section (SC) and breech presentation - PN and SC. RESULTS: For the period, in the first 28 days after birth died 42 (17,7%) infants and 196 (82,3%) were survivors. Depending on the mode of birth statistically significant difference in the incidence of death after birth is not found in vertex presenting newborns (25% CS vs. 16,5% PN; p > 0.05). Unlike in breech presenting fetuses, vaginal birth < or = 32 weeks increases more than twofold neonatal dead compared with CS (20% vs. 7,7%; p < 0.05). Unfavourable outcome in CS is strongly associated with fetal presentation - three times higher neonatal dead in vertex presenting group (25% vs. 7, 7%; p < 0.05), as a result of higher incidence of absolute fetal indications (68,1% vs. 43,2%; p< 0.05). CONCLUSION: The way of birth doesn't affect the frequency of dead within the first 28 days of life in vertex presenting fetuses. Vaginal breech delivery is a risk factor for unfavourable neonatal outcome < or = 32 w.g. Survival in CS is dependent on both fetal presentation and obstetric complications, requiring operation.

[Short term outcome after active obstetric management of very low birthweight infants].

UNLABELLED: Increased survival in infants weighing less than 1500g (VLBW) in recent decades is largely due to active perinatal management and intensive neonatal care. AIMS: To analyze the relationship between antenatal corticosteroid (ACS) administration, mode of delivery and the short term outcome in VLBW infants. METHODS: A total of 563 neonates weighing < 1500 g was studied between 01.01.2008 and 30.06.2010, distributed according the outcome into 3 groups: 330 healthy, 150 with chronic morbidities (bronchopulmonary dysplasia - supplemental O2 at 28 days, intraventricular hemorrhage gr.Ill-IV or cystic periventricular leucomalacia, retinopathy of prematurity gr.llI-V), 83 died. Mode of delivery, ACS and their influence on the outcome were evaluated by multinomial logistic regression analysis and the relative risk was calculated for each of them (OR). The ACS course was taken for completed if applicated in the 7 days before delivery. RESULTS: Lack of ACS significantly increased the risk of severe morbidities or death compared to the complete course: OR 2.6 and 4.9 respectively (p < 0.001). A higher risk was found comparing incomplete to complete course too: morbidities OR 2,3 (p = 0.01), death OR 3,1 (p = 0.01). Incomplete ACS did not improved outcome significantly. Mode of delivery didn't affected significantly the risk of morbidities. The relative risk of death was lower in neonates delivered by cesarean section compared with vaginal breech delivery (OR 0.2, p = 0.005) but higher compared with vaginal vertex delivery (OR 2.1, p = 0,004). In this study we didn't analyze the indications for cesarean section, some of which were due to fetal distress and could influence the outcome. CONCLUSION: The active obstetric management for VLBW infants reduces the risk of death and survival with morbidities. The main protective factor is the complete ACS course.

[Method of delivery and condition of newborn at 25-30 weeks of gestation].

SUMMARY: The aim of this study is to assess the impact of method of delivery--per vias naturales and by CS on condition of preterm newborn < or =30 w.g. MATERIALS AND METHODS: Survey is on a prospective basis for the period 01.2008-12.2009. Total of 95 pregnancies are included meeting the following criteria: pregnancy with a single fetus in occiput position with birthweight appropriate for gestational age 25-30 w.g. 63 of all pregnancies completed by birth per vias naturals and 32 through CS (22 emergency CS and 10 in the planned order). The condition of newborns is found immediately after birth by Apgar score at 1st and 5th minute and the values of pH, BE and blood gases in the blood sample from a.umbilicalis. RESULTS: Comparison of the average values of Apgar 1 st and 5th min, pH, BE, pO2 and pCO2 in preterm born per vias naturals and by CS showed statistically significant difference in three indicators pH, BE and pCO2 and highest frequency of acidosis in an emergency operative abdominal delivery. Juxtapositioning the groups vaginal birth and CS planning in order not found statistically significant differences in BE (p = 0.616), pH (p = 0.399) and pCO2 (p = 0.448). This led to the initial conclusion that the state of newborns in both groups is the same irrespective of birth. After interpretation of the ABS in each case it has been established substantial difference in frequency of uncompensated (0% vs. 19.4%) and compensated metabolic acidosis (50% vs. 36.8%) in premature born through CS in planning orderliness and per vias naturales. CONCLUSION: The method of delivery is a factor which influences the adjacent state of prematurity after birth. The highest incidence of hypoxia is associated with CS in terms of urgency. In comparison with vaginal birth, planned CS in order seems to be a favorable method of delivery for preterm fetus.