Numerical modelling and experimental verification of thermal effects in living cells exposed to high-power pulses of THz radiation.

Exposure of cells or biological tissues to high-power pulses of terahertz (THz) radiation leads to changes in a variety of intracellular processes. However, the role of heating effects due to strong absorption of THz radiation by water molecules still stays unclear. In this study, we performed numerical modelling in order to estimate the thermal impact on water of a single THz pulse as well as a series of THz pulses. A finite-element (FE) model that provides numerical solutions for the heat conduction equation is employed to compute the temperature increase. A simple expression for temperature estimation in the center of the spot of THz radiation is presented for given frequency and fluence of the THz pulse. It has been demonstrated that thermal effect is determined by either the average power of radiation or by the fluence of a single THz pulse depending on pulse repetition rate. Human dermal fibroblasts have been exposed to THz pulses (with an energy of [Formula: see text] and repetition rate of 100 Hz) to estimate the thermal effect. Analysis of heat shock proteins expression has demonstrated no statistically significant difference ([Formula: see text]) between control and experimental groups after 3 h of irradiation.

High Resistance of Potato to Early Blight Is Achieved by Expression of the Pro-SmAMP1 Gene for Hevein-Like Antimicrobial Peptides from Common Chickweed (Stellaria media).

In the common chickweed Stellaria media, two antimicrobial peptides (AMPs), SmAMP1.1a and SmAMP1.2a, have been shown to be proteolytically released as products of the expression of a single gene, proSmAMP1. In this study, the gene proSmAMP1 was introduced into two potato varieties, Zhukovsky ranny and Udacha. These early-maturing varieties were shown to be susceptible to early blight caused by Alternaria spp. Most transgenic lines of either variety having strong expression of the target gene demonstrated high levels of resistance to Alternaria spp. during three years of cultivation, but did not otherwise differ from the initial varieties. Disease severity index (DSI) was introduced as a complex measure of plant susceptibility to early blight, taking into account the diameter of lesions caused by the Alternaria spp., the fungus sporulation intensity and its incubation period duration. Across all transgenic lines, the DSI inversely correlated both with the target gene expression and the copy number in the plant genome. Our results are promising for improving the resistance of potato and other crops to early blight by expression of AMPs from wild plants.

Brain Proteome of Drosophila melanogaster Is Enriched with Nuclear Proteins.

The brain proteome of Drosophila melanogaster was characterized by liquid chromatography/high-resolution mass spectrometry and compared to the earlier characterized Drosophila whole-body and head proteomes. Raw data for all the proteomes were processed in a similar manner. Approximately 4000 proteins were identified in the brain proteome that represented, as expected, the subsets of the head and body proteomes. However, after thorough data curation, we reliably identified 24 proteins unique for the brain proteome; 13 of them have never been detected before at the protein level. Fourteen of 24 identified proteins have been annotated as nuclear proteins. Comparison of three used datasets by label-free quantitation showed statistically significant enrichment of the brain proteome with nuclear proteins. Therefore, we recommend the use of isolated brain preparations in the studies of Drosophila nuclear proteins.

[Cellular Model Based on Laser Microsurgery of Cell Spheroids to Study the Repair Process].

In this study, modern techniques of laser microsurgery of cell spheroids have been used to develop a new simple, reproducible model for studying the mechanisms of repair and regeneration in vitro. Nanosecond laser pulses were applied to perform a microdissection of the outer and the inner zones of the spheroids from dermal fibroblasts. To achieve effective dissection and preservation of spheroid viability, the optimal parameters were chosen: 355 nm wavelength, 100 Hz frequency, 2 ns pulse duration, laser pulses in the range of 7­9 µ J. After microdissection, we observed injury of the spheroids : the edges of the wound surface opened and the angular opening reached a value of more than 180°. As early as during the first hour after spheroid microdissection with laser radiation, the surviving cells changed their shape: cells on the spheroid surface and directly in the damaged area became rounded. One day after microdissection, the structure of the spheroids began to partially recover, the cells in the surface layers began to take the original flattened shape; debris of dead damaged cells and their fragments was gradually cleared from the spheroid composition. In the proposed model, the first data on stimulation of structure recovery of injured spheroids from dermal fibroblasts with a P199 synthetic polypeptide, which is used in cosmetology for the initiation of antiaging and regenerative effects in the skin, were received. After microdissection, recovery of the spheroids structure with a few surface layers of flattened imbricated arranged cells and polygonal cells of the inner zone in the presence of P199 peptide was faster than in the control group, and was completed within 7 days, presumably due to the remodeling of the survived cells.

Laser-based technique for controlled damage of mesenchymal cell spheroids: a first step in studying reparation in vitro.

Modern techniques of laser microsurgery of cell spheroids were used to develop a new simple reproducible model for studying repair and regeneration in vitro Nanosecond laser pulses (wavelength 355 nm, frequency 100 Hz, pulse duration 2 ns) were applied to perform a microdissection of the outer and the inner zones of human bone marrow multipotent mesenchymal stromal cells (BM MMSC) spheroids. To achieve effective dissection and preservation of spheroid viability, the energy of laser pulses was optimized and adjusted in the range 7-9 µJ. After microdissection, the edges of the wound surface opened and the angular opening reached a value of more than 180°. The destruction of the initial spheroid structure was observed in the wound area, with surviving cells changing their shape into a round one. Partial restoration of a spheroid form took place in the first six hours. The complete structure restoration accompanying the reparative processes occurred gradually over seven days due to remodelling of surviving cells.

Parental refusal to diphtheria vaccine: a fatal outcome.

We present a case of a four-year-old boy who succumbed to diphtheria following incomplete course of immunisation, which included diphtheria vaccine. This case report focuses on the issues of parental refusal to vaccines and the development of "halal" vaccines for the prevention of infectious diseases.

Parental refusal to diphtheria vaccine: a fatal outcome

We present a case of a four-year-old boy who succumbed to diphtheria following incomplete course of immunisation, which included diphtheria vaccine. This case report focuses on the issues of parental refusal to vaccines and the development of "halal" vaccines for the prevention of infectious diseases.

Preliminary evaluation of various rapid influenza diagnostic test methods for the detection of the novel influenza A (H1N1) in Universiti Kebangsaan Malaysia Medical Centre.

We evaluated the performance of four rapid influenza diagnostic test methods (RIDT) compared to real-time reverse-transcription polymerase chain reaction (rRT-PCR), for the detection of the novel swine-origin influenza A (H1N1) virus (S-OIV) in August 2009. A total of 270 respiratory specimens were tested with rRT-PCR, where 74 of these were tested by BinaxNow (Inverness), 80 by QuickVue (Quidel), 37 by Influenza A Antigen Rapid Test (Rockeby Biomed) and 79 by Directigen (BD). The sensitivities ranged from 4.4% to 37.0%, specificities 90.9% to 100.0%, positive predictive values 75.0% to 100.0% and negative predictive values 32.3% to 75.0%. RIDT were able to detect S-OIV but the sensitivities were low. The limitations of RIDT must be considered when interpreting results for clinical management.

Risk of blood-borne infection among health care workers in two Kuala Lumpur hospitals.

Health care workers (HCW) are at high risk of acquiring blood-borne diseases. This study compared the risk of infection among HCW in different hospital units and also between HCW and students in medical fields. This cross-sectional study involved pre-tested questionnaires that were completed by 625 HCW and undergraduate students undergoing clinical attachments from February to August 2001. The respondents were separated into two groups: i) HCW from Hospital Kuala Lumpur, HKL (n=241) and Hospital Universiti Kebangsaan Malaysia, HUKM (n=153) ii) Medical students from Universiti Kebangsaan Malaysia, UKM (n=171) and HUKM student nurses (n=60). The results obtained showed that the risk of transmission of blood-borne infections varied significantly according to professional ranks (p<0.05) and to hospital units (p<0.05). The medical intensive care (ICU), haemodialysis, and nephrology and urology units had the highest scores for the risk of infection while the diagnostic laboratory had the lowest risk of infection (p<0.05). Preventive measures taken by the subjects in this study were not satisfactory especially with reference to the use of personal protective equipment and the practice of universal precautions.

Rubella vaccination programme in Malaysia: analysis of a seroprevalence study in an antenatal clinic.

In many developed countries, the incidence of rubella and congenital rubella syndrome (CRS) is considered to be negligible due to the availability of an effective vaccine. However, in Malaysia, several CRS cases are seen every year. This casts doubt on the effectiveness of the rubella vaccination programme. Very few seroprevalence studies were done over the years, making it difficult to discuss the effectiveness of the vaccination programme. The objective of this study is to determine the prevalence of rubella immunity among pregnant women attending antenatal clinics in a local teaching hospital. The hospital database on rubella immunity was assessed retrospectively from August 2001 to June 2002. A cross-sectional study of interviewed method as well as determination of rubella immunity by laboratory tests were carried out in July 2002. A total of 414 women were included, of whom 134 women were interviewed. The rubella immunity status was 92.3%. Based on this figure, rubella vaccination programme in Malaysia is a success despite the presence of CRS cases. Malaysia must ensure rubella vaccine coverage among target groups is high in order to minimise CRS cases.

Hepatitis B immunisation status among health care workers in two Kuala Lumpur hospitals.

Health care workers (HCW) are at higher risk of acquiring blood borne infections such as hepatitis B virus, hepatitis C virus and human immunodeficiency virus from patients. To minimise exposure, Universal Precautions Policy guidelines were introduced. This study looked into one of the aspects of hepatitis B prevention among HCW in the Malaysian context. The objective of this study was to assess hepatitis B vaccine coverage among HCW. A cross sectional study involving pre-tested questionnaires was undertaken from February 2001 to August 2001. Hospital staff in Hospital Kuala Lumpur and Hospital Universiti Kebangsaan Malaysia as well as undergraduate students undergoing clinical attachments were randomly chosen. A total of 625 subjects were enrolled. Only 58.4% had taken a complete hepatitis B vaccination. However, 82.2% have taken at least one dose of the hepatitis B vaccine and were supposed to complete the schedule in due course. Not all HCW were protected against hepatitis B. Preventing hepatitis B in HCW should be one of the priorities of the hospital management as it is definitely cheaper than managing chronic hepatitis B cases.

Respiratory viruses detected in hospitalised paediatric patients with respiratory infections.

Over 200 strains of respiratory viruses cause a variety of human infections ranging from common cold to life-threatening pneumonia. Respiratory viruses implicated in this study are respiratory syncytial viruses (RSV), adenovirus, influenza viruses and parainfluenza viruses. The objective of this study is to determine the epidemiology of respiratory viruses in paediatric patients with lower respiratory tract infection. The methods used were direct antigen detection method, shell vial culture method and conventional tube culture method. The samples included in this study are paediatric patients seen in Universiti Kebangsaan Malaysia Hospital, Kuala Lumpur with suspected acute viral respiratory infection, presenting with acute laryngotracheobronchitis (croup), bronchiolitis and pneumonia. Nasopharyngeal aspirates were collected and processed almost immediately. A total of 222 specimens were received during February 1999 to January 2000 showing a dual peak pattern in the months of April and December. The mean age of the patients was 13 months. Pneumonia (77.9%) was the most common clinical diagnosis in children with lower respiratory tract infection. This was followed by bronchiolitis (19.4%) and croup (27%). Viral aetiologies were confirmed in 23.4% of the patients. The most common respiratory virus isolated or detected was RSV, followed by parainfluenza viruses, influenza viruses and adenovirus.

[Structure of the nucleosome chain. I. Role of histone H1 in oligonucleosome compaction]. / Struktura nukleosomnoi tsepi. I. Rol' gistona H1 v kompaktizatsii oligonukleosom.

The method of sedimentation velocity has been used to study the changes of the oligonucleosome compact state under the influence of various NaCl concentrations and to investigate the role of histone H1 in compaction of nucleosomes. Analysis of dependencies of the sedimentation coefficients on the number of nucleosomes in the chain has demonstrated that histone H1 stabilizes the compact structure of oligonucleosomes in the solution of low ionic strength (mu = 0.01). Removal of histone H1 leads to partial unfolding of the chains of oligonucleosomes. In 0.15 M NaCl solution H1-depleted oligonucleosomes are folded into the compact structure, which is similar to that of oligonucleosomes with histone H1 in solutions of low ionic strength. Further compaction of H1-containing oligonucleosomes in 0.15 M NaCl solution leads to formation of supercoiled structure, stabilized by cooperative interaction of at least five nucleosomes.

[Principles of differential immunodiagnostics in tuberculosis and other pulmonary diseases (author's transl)]. / Prinzipien einer Immundifferentialdiagnostik der Tuberkulose und anderer Lungenkrankheiten.

When differential diagnostics between tuberculosis, sarcoidosis, bronchial carcinoma and non-specific pulmonary diseases is not possible with clinical and laboratory methods, diagnosis may be often put by the aid of immunological methods. Differential diagnostics, usually, has not to delimit all these diseases one from another. In most cases it is necessary to differ only between two of these diseases, tuberculosis versus sarcoidosis, tuberculosis or bronchial carcinoma, tuberculosis or non-specific lung disease. By the aid of antibody determination (against streptococci, staphylococci, and pneumococci), determination of Ig and of immunological tests patterns of values for differential diagnostics between these groups of diseases can be elaborated and are shown in this paper.