Analytical performances of a novel point-of-care procalcitonin assay

Objectives

We report the analytical performances of a new point-of-care (POC) procalcitonin (PCT) fluorescence immunoassay that uses the AFIAS-6© system from Boditech and its concordance with results of the standard method Kryptor Compact plus from the central laboratory.

Design

and methods: Analytical performances including imprecision studies, limit of blank (LoB), limit of detection (LoD) and limit of quantification (LOQ) were determined. The method comparison was performed using plasma vs. whole blood for Kryptor CompactPlus© vs. AFIAS-6©, respectively.

Results

The total imprecision was far from the CV of 4.5% claimed by the manufacturer and close to 10%, for levels of PCT at 0.4 and 8.3 μg/L. The LoD of this novel PCT assay was found to close to the LoD provided by the manufacturer at 0.04 μg/L. The LOQ was higher than that claimed by the manufacturer (0.1 vs 0.002, respectively). The equation of linearity in the lower range was found to be y = 1.056x - 0.039 with r² = 0.993 with a mean recovery percentage of 86 ± 15%. Correlation studies showed a good correlation between PCT measurements using plasma on Kryptor system and on corresponding whole blood with POC reaching a bias of -0.04 in the range from 0.02 to 2 μg/L.

Conclusion

The novel PCT assay on AFIAS-6© is an acceptable POC alternative for the diagnosis and management of sepsis at EDs to improve the flow of patients, as results are consistent with those of the standard PCT Kryptor Compact Plus© assay, despite its higher imprecision.

Serum 25(OH)D and adipokines levels in people with abdominal obesity

Abdominal obesity is a risk factor for cardiovascular disease and diabetes mellitus and has been associated with vitamin D deficiency. Some studies have suggested an association between obesity and adipokine levels as well as low serum 25-hydroxyvitamin D (25(OH)D) level but the underlying mechanisms of the interlink between vitamin D status and serum leptin and adiponectin concentrations are still disputed. We included 435 residents (132 males) from St. Petersburg, Russia into this study. All subjects had physical examination and demographics noted. Blood was collected after an overnight fast and plasma glucose, insulin, serum lipids, 25(OH)D and adipokines (adiponectin and leptin) concentrations were determined at baseline in all participants. Abdominal obesity was diagnosed in 310 (71.3%) subjects (251 females and 59 males). Vitamin D insufficiency and deficiency were found in 314 (72.2%) subjects. Mean (95% CI) age, body mass index (BMI) and serum 25(OH)D for the cohort were 47.6±11.3years; 28.7±0.2kg/m² and 62.5±24.3nmol/l respectively. Serum 25(OH)D level inversely correlated with body weight, waist circumference (WC) and BMI in females but not in males, was lower in diabetic than non-diabetic subjects, and was not significantly different in subjects with and without MetS. WC was positively correlated with leptin and negatively correlated with adiponectin. We found correlation between leptin and serum 25(OH)D level (r=-0.15, p=0.01) but this finding was a characteristic seen only in women. Our study showed a high prevalence of abdominal obesity, vitamin D deficiency and insufficiency in residents from North-West region of Russia, close association between adipokine (leptin, adiponectin) concentrations as well as vitamin D status and body composition (WC, BMI). However in our study the interlink between leptin level and 25(OH)D was found only in females. Further investigations are required to study the relationship between serum 25(OH)D level, obesity and serum adipokine levels.

Prevalence of Vitamin D deficiency in the North-West region of Russia: A cross-sectional study

Russia is a country with geographic and economic preconditions for development of vitamin D deficiency. We analyzed serum 25(OH)D level in residents from North-West region (59-61° North latitude) of Russia to study the prevalence of vitamin D insufficiency and deficiency and its associations with gender, age, obesity and diet. The study population included 1664 residents (1544 adults 18-75 y.o. and 120 children/adolescents of 3-17 y.o.). Serum 25(OH)D was determined in 1226 participants by electrochemiluminescence immunoassay. We used a questionnaire to check the frequency of dairy and fish products intake as well as the use of vitamin supplements. The serum 25(OH)D level was 9.8-147.5nmol/L, mean level in adults population was 54.8±0.7nMol/L, in children/adolescents-46.8±1.6 nmol/L. We revealed that 16.8% of the study population had a 25(OH)D level more than 75nMol/L, 37.5% had insufficiency and 45.7% had vitamin D deficiency. Serum 25(OH)D level in women was lower than in men (53.9±0.8 and 67.2±2.2nmol/L; p<0.01). We did not find association between vitamin D status and age. Patients with normal BMI had higher 25(OH)D level than those with overweight and obesity (52.5±2.8 and 44.8±2.0 nmol/L, p<0.05). Negative correlations between 25(OH)D and BMI (r=-0.17, p=0.03) and WC (r=-0.15, p=0.02) were found. Questionnaire analyses showed that regular fish intake (minimum once per week) was associated with higher 25(OH)D level, while dairy products and vitamin supplements intake did not seem to have any effect on vitamin D status. This study showed high prevalence of vitamin D insufficiency and deficiency in adults and adolescent population from North-West region of Russia, and an association of low serum 25(OH)D level with female gender, obesity and low fish products diet.

[Preterm birth in Bulgaria--changes in aetiology and incidence in the last decade]

There is no decrease in the incidence of preterm birth in Bulgaria and in the world, despite of all the therapeutic and prophylactic efforts. The rate of prematurity in University Maternity Hospital 'Maichin dom' in the last decade has increased significantly- from 11.6% in 2003 to 17.5% in 2013. The numbers are higher than the national average due to the essence of the Hospital being a leading clinical and scientific center. Thorough analysis demonstrates significant increase in the first grade prematurity being 5.8% of all live births in 2003 and 10.2% of all live births in 2013. In fact 58% of all premature births result in first grade preterm newborn. There is no significant increase in the forth grade- severe prematurity in the last decade. We believe that this increase in preterm birth rate is due to several reasons: the success of assisted reproductive technologies, which in Bulgaria leads to a significant increase in the number of multiple pregnancies; destructive/ablative methods of treatment of cervical intraepithelial neoplasia, especially LLETZ (LEEP), postponing of first pregnancy, increase in the number of adult primiparous women and as a whole pregnancy at later age, pregnancy in puberty. All these impose changes in the protocol for pregnancy follow up. Furthermore, we believe it is high time to increase the effectiveness of this service, as lack of adequate follow up is a reason for preterm birth on its own.

[Induced abortion--clinical problems, regulatory gaps, chaos. How much longer?]

Induced abortion is becoming more and more frequent in the contemporary clinical practice. Usually these are pregnant women with diagnosed foetal malformations. Most of them reach a final diagnose in the late second trimester and hence need a pregnancy termination at this gestational age. They are treated in accordance with The Artificial Pregnancy Termination Regulations and put on N 142 clinical-care pathway. The presentation describes the patients' journey form the diagnose through the induced abortion and to the discharge. Analyses the regulations, the multiple inaccuracies and striking omissions with regards to the procedure. Stimulates a discussion on the clinical problems and offers reasonable and realistic solutions.

[Medical abortion 15-22g.w. first experience with mifepriston administration in Bulgaria]

Medical abortion by definition is termination of pregnancy by means of administration of abortifacient pharmaceutical drugs. The most widely spread abortifacients are Mifepriston and Misoprostol. This is the gold standard for induced abortion worldwide, for first trimester, as well as for second. In Bulgaria Mifepriston is available as of June 2014. We represent here our first experience in administering Mifepriston for induced abortion in second trimester. We share our first impressions and discuss the results.

[Mastodynia. Premenstrual syndrome]

Mastodynia is defined as breast tenderness and pain, also called mastalgia. There are several types of cyclic, noncyclic and extramammary. The cyclic mastodynia is the most common one, and represents a clinical symptom of the premenstrual syndrome and of the more severe premenstrual dysphoric disorder. The article outlines different types of mastalgia with their typical clinical features, including the relatively rear Tietze's syndrome and MONDOR'S disease, as well as the PMS and the PMDD. The authors also offer a diagnostic algorithm and specific diagnostic criteria. There is also a discussion on the main treatment alternatives being symptomatic treatment of the most troublesome symptoms or alteration of the menstrual cycle and a brief discussion on the pharmaceutical preparations used for treatment including the administration of selective serotonin reuptake inhibitors (SSRI).

[Pregnancy termination in Bulgaria – past, present and future perspectives. Drugs induced abortion – guidelines by WHO]

There are still too many unsafe abortions performed worldwide. Together with the efforts to reduce the abortion by choice, we note a rise in the need for mid trimester pregnancy termination for medical reasons. The article looks at the past present and future perspective of the abortion as a procedure in Bulgaria. States the fact that medical abortion is officially not widely performed. We reckon that with the existing guidelines by WHO and with Mifepriston and Misoprostol recently registered in Bulgaria, it is time for the medical abortion to become part of the clinical practice in Bulgaria. We believe that early medical abortion as well as mid trimester induced abortion is and adequate if not better alternative to the existing in Bulgaria procedures.

[Mid trimester pregnancy termination--review of the caseload for 2012 of Maternity University Hospital 'Maichin Dom', Sofia, Bulgaria]

Midtrimester pregnancy termination is yet an ongoing clinical issue in spite of the hard work on the matter in the recent years. There is a significant withdrawal from the surgical methods, absence of adequate drug preparations for medical termination and absence of guidelines for such form the Bulgarian Society of Obstetricians and Gynaecologists. In order to obtain a clear view on the current situation, we made a review on all the cases of midtrimester induced abortion in Maternity University Hospital 'Maichin dom' for the year of 2012. We found that the mid trimester abortions represent 11.7% of all abortions performed in the hospital in 2012. Most widely used are the following methods: vaginal application of prostaglandin E2 vag. tabl. 3 mg--33.5%, intrauterine balloon-catheter application after priming of the cervix with prostaglandin E2 3 mg--18%, prostaglandin F 2alpha as intrauterine extraamniotic continuous infusion through a balloon catheter, noweighton--9%, vaginal application of Prostaglandin E1--5.4%. Surgical termination was used in as little as 6% of the cases. The shortest interval for expulsion had been registered with the application of PG E1--19'55", compared with the most widely spread method of application of PG E2, which was more than twice longer--42'12". Application of balloon catheter, after priming of the cervix with 3 mg PG E2 vag. tabl. proved to be inefficient with mean interval for expulsion of 88'42". Surgical termination for midtrimester pregnancy is seen as the last alternative, it is rarely applied and mostly as anurgent procedure. In conclusion, the existing regimes for medical termination of midtrimester pregnancy are inefficient; application of 3 mg PG E2 is ineffective during the second trimester, insertion of balloon catheter attached to a weight is unacceptable. It is highly recommended that more attention is paid to the surgical termination with regards to residence training programmes and maintaining of qualification. This is needed as the procedure is usually performed to stop life threatening bleeding and is hence urgent. We underline the necessity of adequate guidelines for midtrimester medical termination. They should be based on Misoprostol as this is the gold standard for this gestational age. We believe there is enough clinical and scientific evidence for its safety and efficacy. Moreover, we are happy to announce that Misoprostol is already registered in Bulgaria.

[Nonspecific immunomodulation in obstetrics and gynecology with Ecomer preliminary report]

The article gives a brief description of "Ecomer", preparation containing shark liver oil. Main immunoactive ingredient of the shark liver oil are the alkylglycerols. The main characteristics of alkylglycerols are noted together with their mechanism of action. There is also a list of indications for Ecomer administration. There is a summary of the authors' experience with Ecomer, its efficacy in ObGyn being the main aim of this study.

METHODS AND MATERIALS

For the purpose of the study Ecomer is given to two main groups of patients: I-pregnant women between 27 and 36 weeks of gestation having two subgroups: 1--with 8 women with naso-pharyngeal complaints and 2--with 13 patients with urinary tract complaints, suggestive of cysto-pyelitic disorders and II main group of patients operated for cervical cancer in different stages with two subgroups--1 with 17 patients with Ecomer intake started at the beginning of the radiation therapy, and 2 with 6 patients who began taking Ecomer before the beginning of the radiation therapy, after having a histologically proved diagnose. The I group took two capsules of Ecomer three times a day for 15 days or less if asymptomatic earlier; in the II group Ecomer was taken two capsules three times a day for 2 months, then one capsule three times a day for a month, followed by a repetition of the scheme.

RESULTS

In the pregnant women group, improvement was noticed in 75% in the first subgroup and in 76% in the second subgroup. In the second main group the interpretation of results is hindered by the insufficient time interval. Nevertheless, fewer side effects of the radiation therapy was noticed in both groups. Improvement in the survival rate is yet to be followed up.

CONCLUSIONS

Administration of Ecomer in pregnant women with naso-pharyngeal problems led to improvement in their general condition and less frequent need to prescribe antibiotics. In pregnant women with urinary tract problems, Ecomer resulted in easing the pain faster and lowered the recurrence risk. In women with cervical cancer, the treatment is quite aggressive and the opportunity to diminish the side effects by administration of a natural and harmless preparation should not be omitted.

Temperature dependence of resonance Raman spectra of carotenoids

To understand the mechanism of the photoprotective and antioxidative functions of carotenoids, it is essential to have a profound knowledge of their excited electronic and vibronic states. In the present study we investigate the most powerful antioxidants: β-carotene and lutein by means of resonance Raman spectroscopy. The aim was to study in detail their Raman spectra in solution at room temperature and their changes as a function of temperature. To measure the spectra in their natural environment pyridine has been used as a solvent. It has been chosen because of its polarizability (n=1.5092) which is close to that of membrane lipids and proteins. The temperature dependence of the most intensive ν(1) band in the range from 77 K to 295 K at 514.5 nm excitation has been obtained. It was found that in pyridine the CC stretching frequency, its intensity, line shape, and line width are very sensitive to the temperature (the sensitivity being different for the two studied carotenoids). The observed linear temperature dependence of the CC stretching frequency is explained by a mechanism involving changes of the vibronic coupling and the extent of π-electron delocalization. The different behavior of the temperature-induced broadening of the ν(1) band and its intensity for the two studied carotenoids can be associated with the different nature of their solid matrices: glassy for β-carotene and crystalline-like for lutein, owing to their different chemical structures.

[Some aspects of prostaglandin administration in obstetrics: preliminary report]

Prostaglandin preparations are widely used in the OB-GYN practice today. This is due to their high efficiency and their potency to prevent a surgical intervention and serious complications. The aim of this study is to share our experience in the prevention of hypo- and atonic, itra- and postoperative hemorrhage after Caesarian Section on multiple pregnancy.

MATERIALS AND METHODS

31 patients with multiple pregnancy for the period of Jan 2010 to June 2011, delivered by Cesarean Section due to unfavorable fetus presentation. Time of delivery- 34 to 38 weeks of gestation. 13 of them represented our work group, amongst them 11 with twin pregnancy and 2 with triplets. They were administered, in theatre, prostaglandin F2alpha as 1 ampule of Prostin 15M (Carboprost tromethamole 0.25 mg) in the uterus wall, as a prophylaxis. The control group consisted of 18 multiple pregnancy patients, chosen randomly and delivered again by C.S., 14 of them with twin pregnancy and 4 with triplets.

RESULTS

In our work group the average maternal blood loss was 520 ml +/- 104 ml, compared to 760 +/- 80 ml in the control group. There were patients in the control group with average blood loss of 1500 ml leading to the need of urgent and lifesaving measures.

CONCLUSIONS

Nevertheless the small number of cases we had, we dare to say the administration of Carboprost tromethamole - Prostin 15M, intramurally in the uterus during Cesarean section on multiple pregnancy, diminishes the risk of severe hypo- and atonic hemorrhage in theatre and postpartum.

[Our experience with management of inherited thrombophilia during pregnancy. Preliminary report]

It has become clear in the recent years that inherited thrombophilias (IT) are associated with serious abnormalities during pregnancy. This includes miscarriage, still birth, placental abruption, praeclamcspia and intrauterine fetal growth restriction. The aim of this study is to share our experience in the field.

MATERIALS AND METHODS

38 patients with medical history of abnormal pregnancies (miscarriage, still birth, placental abruption, praeclamcspia and intrauterine fetal growth reastriction). They were all tested for the following gene alterations: V Laidon-R506Q/phiVL-R506Q/, protrombin G/A 20210 /Pi pG/A20210/, Plasminogen activator inhibitor- PAI- 4G/4G/PAI 4G/5G/). IT were diagnosed in 24 patients. They were all treated by: Aspirin 75 mg form prior to conception and low molecular Heparin after detection of fetal heart movement. Due to the observed NRDS in some of the newborns, the low molecular heparin intake was discontinued 30 days prior to expected delivery.

RESULTS

keeping up to the therapeutic scheme, 70% (17) of women with IT gave birth to a term baby, and 30% (7)-to a preterm one, all pregnancies were successful. Amongst the patients with medical history of miscarriage, 72% were diagnosed with IT and 87.5% of them gave birth to a term newborn as a result of the anticoagulant treatment.

CONCLUSIONS

Undiagnosed IT is a common cause of adverse pregnancy outcome. Uninterrupted anticoagulant treatment of these patients is very successful. The whole pregnancy should be followed up closely. Due to the higher risk of respiratory complications in the infants, delivery should be performed in a specialized hospital with neonatology department, capable of newborn resuscitation.

[Our experience with management of inherited thrombophilia during pregnancy. Preliminary report]

The physiologic mechanism that results in the occurrence of premenstrual syndrome (PMS) is not well understood.

OBJECTIVE

Effective treatment in premenstrual syndrome with vitex agnus castus--femicur N in adolescent girls. [corrected].

MATERIAL AND METHODS

We have investigated 45 adolescent girls 14-16 years old for a 3 years period from march 2009 to march 2011. The first group of 23 girls were prescribed Femicur N 4 mg once daily for 3 month--90 capsules per course. The second group of 22 girls were given 40 mg of the study drug (Femicur N) twice a day, from the 19th day of the first day of the cycle for 10 days 3 month as the dose is 60 capsules per course.

RESULTS

Our investigation showed that therapy with VAC-Femicur N in adolescents suffering from PMS was effective and the results were good. From 45 girls 20 girls (44.4%) were without any complaints and 13 girls (28.8%) had reduction of all premenstrual symptoms. In both groups premenstrual mastodynia in 13 girls (28.8%) has disappeard and with 4 girls (8.8%) complaints were redused.

[Our experience with management of inherited thrombophilia during pregnancy: preliminary report]

It has become clear in the recent years that inherited thrombophilias (IT) are associated with serious abnormalities during pregnancy. This includes miscarriage, still birth, placental abruption, praeclamcspia and intrauterine fetal growth restriction. The aim of this study is to share our experience in the field.

MATERIALS AND METHODS

38 patients with medical history of abnormal pregnancies (miscarriage, still birth, placental abruption, praeclamcspia and intrauterine fetal growth reastriction). They were all tested for the following gene alterations: V Laidon- R506Q/phiVL-R506Q/, protrombin G/A 20210/pG/A20210/, Plasminogen activator inhibitor- PAI- 4G/4G /PAI 4G/5G/). IT were diagnosed in 24 patients. They were all treated by: Aspirin 75mg form prior to conception and low molecular Heparin after detection of fetal heart movement. Due to the observed NRDS in some of the newborns, the low molecular heparin intake was discontinued 30 days prior to expected delivery.

RESULTS

keeping up to the therapeutic scheme, 70% (17) of women with IT gave birth to a term baby, and 30% (7)- to a preterm one, all pregnancies were successful. Amongst the patients with medical history of miscarriage, 72% were diagnosed with IT and 87.5% of them gave birth to a term newborn as a result of the anticoagulant treatment.

CONCLUSIONS

Undiagnosed IT is a common cause of adverse pregnancy outcome. Uninterrupted anticoagulant treatment of these patients is very successful. The whole pregnancy should be followed up closely. Due to the higher risk of respiratory complications in the infants, delivery should be performed in a specialized hospital with neonatology department, capable of newborn resuscitation.

[Antenatal ambroxol administration for prevention of respiratopry distress syndrome in preterm infants: preliminary report]

The rate of preterm births has remained unchanged for the recent years despite of the persistent attempts to diminish it. Preterm births are responsible for about 70% of neonatal morbidity and mortality. One of the main problems of preterm newborns is their lung immaturity. The aim of this study is to assess the effect of Ambroxol, given prenatally on the rate and severity of neonatal respiratory distress syndrome (NRDS) in preterm infants and its potential to replace the corticosteroid prophylaxis in cases where steroids are contraindicated or undesirable.

MATERIALS AND METHODS

The trial consisted of 33 pregnant women between 27 and 32 week of gestation. 17 of them represented our work group and were given Ambroxol syrup 15 mg/ml, per os 30 ml in three intakes, for 7 days. 16 were controls and were not given any kind of NRDS prophylaxis.

RESULTS

severe NRDS was diagnosed in 2.5 times more cases in the control group compared to the work group. All infants in the control group had clinical signs of NRDS, while 23.5% of the infants in the work group were asymptomatic. Bronchopulmonary dysplasia was diagnosed in 25% of the infants in the control group, compared to none diagnosed in the work group. Newborns with no antenatal NRDS prophylaxis had to be kept in intensive care units for an average period of time twice longer than the newborns to mothers who had received Ambroxol.

CONCLUSIONS

Antenatal Ambroxol administration diminishes the rate of NRDS, decreases the duration, scope and price of the intensive care, lessens the duration of assisted ventilation and oxygen needs and hence improves the long-term outcome. Ambroxol and steroids have cumulative effect on fetal lung maturation and therefore should both be a part of the preterm delivery therapeutic scheme.

[Midtrimester pregnancy termination--contemporary methods and techniques. Review]

The improvement in the diagnostic procedures for early detection of fetal abnormalities has led to an increase in the number of induced mid-trimester pregnancy terminations. Hence, the total number of pregnancies terminated in the second trimester comprises somewhere between 10 and 15% of all terminations, but they are responsible for 2/3 of the complications and half of the deaths. These simple facts draw our attention to the procedure. There are two main types of mid-trimester termination- surgical and medical. Surgical methods require special skills and qualification, while medical methods are considered safer and are more common. The latter group includes Oxytocin i.v., prostaglandin preparations Pg E2, Pg F2alpha, Pg E1 and their synthetic analogues, antiprogesteron drugs and etc. We have reviewed Bulgarian and foreign scientific resources and articles. We have outlined the recommendations of The Royal College of Obstetricians and Gynaecologists and William's Obstetrics. Also we have cited some relevant trials and we have made a short review of the available on the Bulgarian market prostaglandin preparations for mid-trimester pregnancy termination.

[Treatment of preterm delivery--therapeutic algorithm]

In the recent years the rate of preterm deliveries has not been brought down despite of the new therapeutic management and medications. The aim of this scientific report is to share our algorithm of preterm delivery prevention.

MATERIALS AND METHODS

Our trial consisted of 23 patients between 26 and 36 weeks of gestation diagnosed with preterm delivery, for a one year period - May 2010 to May 2011. The following therapeutic algorithm was applied: magnesium preparations, B2-mymetics, if no improvement was seen in 24 hour period we continued with Utrogestan, Calcium channel blockers, Indomethacin. Progesterone, who hasn't so far been administered in this gestational age, followed this algorithm: loading dose of three tablets, followed by therapeutic dose of 1 to 2 tablets 3 times a day, and a maintenance dose of 1 tablet 3 times a day. Pregnant wemen under 35 completed gestational weeks were also administered steroid i.m. for prevention of neonatal RDS, followed by Ambroxol per orally.

RESULTS

Our new algorithm prolonged pregnancy for more than 14 days in 82.6% of the cases. Delivery. was postponed with 7 days in 17.4% of the cases, with up to 14 days in 30.4%, with up to 21 days in 26.1% and with more than 21 days in 26.1% of the cases.

CONCLUSIONS

Including progesterone in our common therapeutic scheme we were able to prolong pregnancy significantly.

[HE4--a new tumor marker for ovarian cancer]

AIM

Ovarian cancer is the fourth most common cause of cancer-related death in women worldwide. In Europe, the mortality rate range is from 3.6 to 9.3 per 100 000 women; the symptoms are mostly unspecific. Compared to often used CA 125 HE4 is a tumor marker that provides more specific and earlier diagnostic of ovarian cancer.

MATERIAL AND METHODS

The HE4 is a solid-phase, non-competitive immunoassay. After the required incubation an enzyme-linked monoclonal antibody are added; followed by substrate solution, which develops color reaction in proportion to the amount of HE4 in serum.

RESULTS

For a period of seven months we investigate 55 patients for ovarian cancer. The age was between 25 and 60. In 17 cases the levels of HE4 and CA125 were both elevated. In 8 cases we found no deviation from the normal ranges. In the rest 30 cases the levels of He4 were high, in spite of low CA125 levels. The followed biopsies confirmed the diagnosis ovarian cancer.

CONCLUSION

HE4 is vastly more specific and early-phase diagnosed tumor marker in cases with ovarian cancer. Its common usual would reduce the mortality from this social disease.

[Current protease-antibody-based serodiagnostic tools and their use in the diagnosis of autoimmune thyroid diseases]

The purpose of the investigation was to comparatively study the possible clinicodiagnostic and clinicoprognostic value of thyroglobulin (TG) autoantibodies (anti-TG autoAB) and thyroid peroxidase (TPO) (anti-TPO autoAB) with proteolytic activity (protease-AB) and to develop additional clinicoimmunological criteria for working out a protease-AB-based laboratory serodiagnosis protocol. Sera from 240 patients with autoimmune thyroiditis (AIT), 124 with diffuse toxic goiter (DTG), and 172 with other thyroid diseases were studied. Serum from 40 clinically healthy donors served as a control. Sera were screened for anti-TG and anti-TPO autoAB by enzyme immunoassay and/or radioimmunoassay. Nonspecific proteolytic activity was determined, by incubating a highly purified AB IgG-isotype solution with nonspecific substrate (such as BSA-FITS or thyoredoxine/Trx), followed by the measurement of relative fluorescence shifts at a wavelength of 470 nm. The blood samples taken from patients with AIT or DTG and the highly purified anti-TG or anti-TRO autoAB of IgG isotype were incubated with appropriate human substrates to determine AG-specific proteolytic activity. Proteolysis products were detected by PAAG electrophoresis. An association was found between the rise in the frequency of protease AB, their catalytic activity, a tendency toward autoAB between themselves, and the degree of thyroid tissue degradation in AIT and DTG; some specific features of a serological pattern were noted in diferent dorms of AIT and DTG. For example, the prevailing autoABs have been shown to be TG-specific in AIT and TPO-specific proteases in DTG; also, the detectable catalytic activity of both autoAB in AIT is an order of magnitude higher than that in DTG. No protease ABs have been recorded in other forms of thyroid diseases in which antithyroid autoABs are also frequently detected. The screening procedure for protease AB may be considered as a highly sensitive and specific indicator test in the diagnosis and prediction of AIT and DTG, which allows one to diagnose not only within the framework of major thyroid nosological entities, but much broader, by covering a great variety of syndromal forms of pathology.

Spastin gene mutations in Bulgarian patients with hereditary spastic paraplegia

Hereditary spastic paraplegia (HSP) is an extremely heterogeneous group of neurodegenerative disorders affecting the longest axons in the central nervous system. The most common genetic form accounting for about 40% of the autosomal-dominant HSP (ADHSP) cases is spastin gene, SPG4. We performed mutation screening of the spastin gene on 36 unrelated HSP patients from three different ethnic groups (Bulgarian, Turks and Gypsies) and found four new mutations and one already reported. The phenotype-genotype correlations in Bulgarian SPG4 patients showed a great difference in the age at disease onset between patients with missense mutations and those harboring deletions and splice-site mutations. Our study is the first to present corroborative clinical data in favor of the general hypothesis that the clinical course of the disease is related to the type of the spastin mutation. The clinical and genealogical findings in Bulgarian SPG4 patients suggest that a positive family history for inheritance as an autosomal-dominant trait is a strong indication for spastin mutation screening.

Assessment of the CASP4 fold recognition category

We present the assessment of the CASP4 fold recognition category. The tasks we had to execute include the splitting of multidomain targets into single domains, the classification of target domains in terms of prediction categories, the numerical evaluation of predictions, the mapping of numerical scores to quality indices, the ranking of predictors, the selection of top-performing groups, and the analysis and critical discussion of the state of the art in this field. The 125 fold recognition groups were assessed by a total score that summarizes their performance over all targets and a quality score reflecting the average quality of the submitted models. Most of the top-performing groups achieved respectable results on both scores simultaneously. Several groups submitted models that were much closer to the respective target structures than any of the known folds in the Protein Data Bank. The CASP4 assessment included the automated servers of the parallel CAFASP experiment. For the total score, the highest rank achieved by a fully automated server is 12. Two thirds of the predictors have rather low scores.

Effect of modification of light-harvesting complex II on fluorescence properties of thylakoid membranes of Arabidopsis thaliana

The 77 K chlorophyll fluorescence spectra of Arabidopsis thaliana mutants deficient in lipid fatty acid desaturation have been used in order to further explore the influence of the modification of LHC II after mutation and proteolitic treatment on the energy transfer between the chlorophyll-protein complexes, as well as on the structure-function relationship in the supramolecular complex of Photosystem II. The gaussian decomposition and analysis of the fluorescence bands associated with PS II complex show the controversial action of the trypsin in the investigated thylakoid membranes. This reveals that the organization of PS II complexes is different in the wild type and both mutants indicating altered connection between the LHC II and the RC core complexes of PS II in both mutants. The results obtained demonstrate that different amounts of oligomer and monomer forms of LHC II in the mutants (LK3 and JB67), arising from lipid modification, are responsible for different proteolytic action in their thylakoid membranes.

Structure-based evaluation of sequence comparison and fold recognition alignment accuracy

The biological role, biochemical function, and structure of uncharacterized protein sequences is often inferred from their similarity to known proteins. A constant goal is to increase the reliability, sensitivity, and accuracy of alignment techniques to enable the detection of increasingly distant relationships. Development, tuning, and testing of these methods benefit from appropriate benchmarks for the assessment of alignment accuracy.Here, we describe a benchmark protocol to estimate sequence-to-sequence and sequence-to-structure alignment accuracy. The protocol consists of structurally related pairs of proteins and procedures to evaluate alignment accuracy over the whole set. The set of protein pairs covers all the currently known fold types. The benchmark is challenging in the sense that it consists of proteins lacking clear sequence similarity. Correct target alignments are derived from the three-dimensional structures of these pairs by rigid body superposition. An evaluation engine computes the accuracy of alignments obtained from a particular algorithm in terms of alignment shifts with respect to the structure derived alignments. Using this benchmark we estimate that the best results can be obtained from a combination of amino acid residue substitution matrices and knowledge-based potentials.

Restricted expression of G86R Cu/Zn superoxide dismutase in astrocytes results in astrocytosis but does not cause motoneuron degeneration

Evidence garnered from both human autopsy studies and genetic animal models has suggested a potential role for astrocytes in the pathogenesis of amyotrophic lateral sclerosis (ALS). Currently, mutations in the gene encoding Cu/Zn superoxide dismutase (SOD1) represent the only known cause of motoneuron loss in the disease, producing 21q linked familial ALS (FALS). To determine whether astrocytic dysfunction has a primary role in familial ALS, we have generated multiple lines of transgenic mice expressing G86R mutant SOD1 restricted to astrocytes. In GFAP-m SOD1 mice, astrocytes exhibit significant hypertrophy and increased GFAP reactivity as the animals mature. However, GFAP-mutant SOD1 transgenic mice develop normally and do not experience spontaneous motor deficits with increasing age. Histological examination of spinal cord in aged GFAP-mSOD1 mice reveals normal motoneuron and microglial morphology. These results indicate that 21q linked FALS is not a primary disorder of astrocytes, and that expression of mutant SOD1 restricted to astrocytes is not sufficient to cause motoneuron degeneration in vivo. Expression of mutant SOD1 in other cell types, most likely neurons, is critical for the initiation of disease.

Polarized fluorescence spectroscopy of oriented isolated spinach Photosystem I particles

The fluorescence anisotropy of Photosystem I (PS I) particles, isolated from spinach chloroplasts and containing approximately 200 chlorophyll molecules per reaction center, is investigated at low temperatures. The particles are oriented by squeezing in polyacrylamid gels with different macroscopic deformation parameters. Fluorescence anisotropy is measured upon steady state excitation with a laser line at 632.8 nm. A formula for the fluorescence anisotropy in oriented Photosystem I particles is applied for a different polarization of the linearly polarized exciting light. Our calculations are based on the consideration of the Photosystem I complex as a triple-chromophore complex: the absorbing chlorophyll molecules (chl), belonging to the light-harvesting complex of PS I (LHC), and two fluorophores, emitting at 720 nm (F720) and at 735 nm (F735), respectively. Using polarized fluorescence spectroscopy with a different polarization of the linearly polarized exciting light, the experimental dependence of the fluorescence anisotropy on this polarization is obtained. Based on this dependence and applying the derived formula, as a first approximation, both the orientation of the photosynthetic pigments with respect to the membrane and their mutual orientation are determined in PS I particles. As the most probable average orientational angles in PS I particles, we obtained the values 35 degrees / 50 degrees , 50 degrees / 60 degrees , and 65 degrees / 67 degrees for the absorbing dipoles of chl and for the emission dipoles of F720 and F735, respectively, with the normal of the plane of the membrane. For their mutual orientation, the following limits are determined: 10 degrees / 20 degrees , 40 +/- 2 degrees , 20 degrees / 30 degrees for the angles between chl and F720, chl and F735; and F720 and F735, correspondingly. Of course, the values of the angles estimated as a result of our study are an average value of all angles of the excited transitions and must be considered as their first approximation valid for the idealized case when all PS I particles are oriented in gel.

Regulation of rDNA transcription in chloroplasts: promoter exclusion by constitutive repression

Spinach chloroplasts contain two types of RNA polymerases. One is multimeric and Escherichia coli-like. The other one is not E. coli-like and might represent a monomeric enzyme of 110 kD. The quantitative relation of the two polymerases changes during plant development. This raises the question, how are plastid genes transcribed that contain E. coli-like and non-E. coli-like promoter elements during developmental phases when both enzymes are present? Transcription of the spinach plastid rrn operon promoter is initiated at three sites: P1, PC, and P2. P1 and P2 are preceded by E. coli-like promoter elements that are recognized by E. coli RNA polymerase in vitro. However, in vivo, transcription starts exclusively at PC. We analyzed different promoter constructions using in vitro transcription and gel mobility-shift studies to understand why P1 and P2 are not used in vivo. Our results suggest that the sequence-specific DNA-binding factor CDF2 functions as a repressor for transcription initiation of the E. coli-like enzyme at P1 and P2. We propose a mechanism of constitutive repression to keep the rrn operon in all developmental phases under the transcriptional control of the non-E. coli-like RNA polymerase.