PROCEEDINGS OF THE LATVIAN ACADEMY OF SCIENCES

SECTION B: NATURAL, EXACT AND APPLIED SCIENCES
(ISSN 1407-009X, Language: English)

Volume 60 (2006) Number 2/3

IMMUNOLOGICAL ASPECTS IN THE PATHOGENESIS OF ROSACEA

Inese Kolontaja*, Ināra Ančupāne**, Ingmārs Mikažāns*, Helēna Mikažāne***, and Evita Niedrīte*
* Department of Dermatovenerology, Rīga Stradiņš University, Dzirciema iela 16, Rīga LV-1007, Latvia
** Children Clinical University Hospital, Vienības gatve 45, Rīga, LV-1004, Latvia
*** Department of Internal Diseases, Rīga Stradiņš University, Dzirciema iela 16, Rīga, LV-1007, Latvia
Proc. Latvian Acad. Sci., Section B, Vol. 60 (2006), No. 2/3, pp. 45–50.

Rosacea is a relatively common skin disease mostly affecting women at the ages of 40–50. Rosacea accounts for up to 1% of all cases seen in dermatological departments. Presently in Latvia we are facing a problem of increasing numbers of severe forms of rosacea. The disease affects the aesthetic function of the skin causing psychological burden that in due course reduces the life quality. The clinical signs of rosacea divide into five stages: erythematous, papulous, pustulous, nodulo-cystic, and infiltrative. Clinical signs vary widely from few symptoms to heavy destructive manifestations, which require surgical treatment. Therefore, a timely diagnostics and treatment really matter, paying special attention to increased quality of patient’s life. A successful treatment combines the aethiological, pathogenetical and symptomatical therapy. The target of this publication is to summarise the latest literature entries on the pathogenesis of rosacea and to provide an insight into applying the well-founded therapy in clinical practice.

Key words: rosacea, pathogenesis, immunology.

EFFECT OF ANNEALING ON VARIOUS DIELECTRIC FUNCTIONS AND REFRACTIVE INDEX OF LEAD IODIDE SINGLE CRYSTALS

Mahmoud Hassan* and Marie Matuchova**
* Electronics Engineering Department, Princess Sumaya University, P.O. Box 1438, Al-Jubaiha, 11941, Amman, Jordan; E-mail: m.hassan@psut.edu.jo
** Institute of Radio Engineering and Electronics, Czech Academy of Science, Praha, Czech Republic
Proc. Latvian Acad. Sci., Section B, Vol. 60 (2006), No. 2/3, pp. 51–54.

The effects of annealing on AC conductivity, dielectric constants, loss tangent, and impedance and refractive index of lead iodide (PbI₂) single crystals were investigated. The annealing temperature range was between room temperature and 110 °C at different frequencies between 100 Hz –100 kHz. The purpose of measurements was to study structural defects, impurities, and surface conditions of lead iodide single crystals.

Key words: lead iodide, dielectric constant, loss tangent, refractive index, trapping centres, structural defects.

EXISTENCE OF TOLL EQUILIBRIUM IN TRAFFIC NETWORK WITH DRIVERS HAVING DIFFERENT TIME VALUES

Leonid Engelson
Centre for Traffic Research, The Royal institute of Technology, Stockholm, SWEDEN
Proc. Latvian Acad. Sci., Section B, Vol. 60 (2006), No. 2/3, pp. 55–57.

In this paper, the purpose of traffic management is formulated as a set of constraints imposed on traffic flows along some links in the road network. The discussed problem is: what charges one has to inflict the drivers on the links so that the traffic volumes on these links satisfy certain upper bounds. While well investigated in the situation when all drivers have the same time value, the problem with drivers having different time values, although more realistic, did not receive much attention. The paper presents a proof that a solution to this problem exists under a natural condition that the whole travel demand can be served by the road network within the imposed constraints.

Key words: optimisation, multi-class traffic equilibrium, congestion pricing, variational inequalities, side constraints.

ASSESSMENT OF ROAD BUILDING WORKER PHYSICAL WORKLOAD USING QUALITATIVE AND QUANTITATIVE ERGONOMICAL RISK ANALYSIS METHODS

Ženija Roja^*, Maija Eglīte^**, Valdis Kaļķis^*, and Henrijs Kaļķis^***
* Faculty of Chemistry, University of Latvia, K. Valdemāra ielā 48, Rīga, LV-1013, LATVIA; E-mail: Valdis.Kalkis@lu.lv
^**Institute of Occupational and Environmental Health, Rīga Stradiņš University, Dzirciema ielā 16, Rīga, LV-1007, LATVIA
^*** Faculty of Economics and Management, University of Latvia, Aspazijas bulv. 5, Rīga, LV-1050, LATVIA
Proc. Latvian Acad. Sci., Section B, Vol. 60 (2006), No. 2/3, pp. 58–64.

The present work is focused on occupational health problems caused by ergonomic risks in the road building industry, where workers are employed in the building of concrete pavement coverings, profiling and levelling of gravel covering and asphalt-concrete spreading. Applying worldwide approved qualitative ergonomic analyses (QEC, OWAS, NIOSH a.o.) and experiments to determine consumed metabolic energy using heart rate monitoring, the following work risk degree and work hardness categories were used: road workers – risk degree IV, category III (hard work, 7,5 ± 1,5 kcal/min); pavers – risk degree IV, category II (moderate work, 6,5 ± 1,0 kcal/min). It was proved that the metabolic energy consumption determined via experiments is not in line with calculated energy consumption applying qualitative analysis methods. The real energy consumption is smaller than the calculated consumption, showing that in mathematical calculations rest breaks characteristics are not considered. The necessary frequency of rest breaks for workers working with metabolic energy consumption 7- 8 kcal/min was 18- 20 minutes of rest after each work hour. If the work is performed with short 3–5 min breaks, the result is an ability to work much longer and perform a much greater amount of work. Job rotation in the work shift for road repair workers is one of the ways to decrease energy consumption and muscle fatigue. Recommendations for job rotation times of road workers are: road repairing four hours, working with road roller four hours.

Key words: building industry, workload, energy consumption, muscular and skeletal system, heart rate

CUTANEOUS VASOMOTOR DYSFUNCTION IN CHERNOBYL CLEAN-UP WORKERS

Pēteris Tretjakovs^*+, Sandra Vestermane^*, Anda Rozenbaha^*, Ojārs Rubens^*, Antra Jurka^*+, Ināra Logina^*++, and Michael Donaghy^***
* Pauls Stradiņš Clinical University Hospital, Pilsoņu iela 13, Rīga, LV-1002, LATVIA; E-mail: tretjako@latnet.lv
⁺ Institute of Experimental and Clinical Medicine, University of Latvia, O. Vācieša iela 4, Rīga, LV-1004, LATVIA
⁺⁺ Rīga Stradiņš University, Dzirciema iela 16, Rīga, LV-1007, LATVIA
^*** Department of Clinical Neurology, University of Oxford, Oxford OX2 6HE, UK
Proc. Latvian Acad. Sci., Section B, Vol. 60 (2006), No. 2/3, pp. 65–69.

Nuclear spill clean-up workers from the 1986 Chernobyl accident frequently report pain, sensory disturbances, discolouration, and sweating of hands and feet. Twenty-three Latvian former clean-up workers with such symptoms were investigated for peripheral and autonomic neuropathy, lead intoxication, and skin blood flow. Nerve conduction studies and cardiovascular autonomic testing showed no large fibre peripheral or autonomic neuropathy, and blood lead levels lay below the toxic range. Laser Doppler fluximetry, compared to age-matched controls, showed no significant differences in basal microvascular skin perfusion at the great toe (107 ± 105 in patients (P) vs. 77% ± 55 PU in controls (C)). The inspiration-induced decrease of basal laser Doppler flux was significantly impaired (21.6 ± 15.4 (P) vs. 39.2 ± 14.5% (C) P < 0.001). Postocclusion hyperaemia was also decreased (205 ± 138 (P) vs. 270 ± 85 PU (C) P < 0.05) as was heat-induced hyperaemia (11 ± 63 (P) vs. 185 ± 75 PU (C), P < 0.001). These findings show that Chernobyl clean-up workers have significant persisting cutaneous microvascular regulatory dysfunction without evidence of generalized peripheral or cardiovascular autonomic peripheral neuropathy.

Key words: Chernobyl clean-up workers, sensory complaints, cutaneous vasomotor response, laser Doppler flowmetry.

TREATMENT OF FAILED BACK SURGERY SYNDROME: EPIDURAL STEROID INJECTION

Iveta Golubovska*, Juris Stīpiņš*, Rolands Gibners*, and Indulis Vanags**
* Hospital of Traumatology and Orthopaedics, Duntes iela 12/22, Rīga, LV-1005, LATVIA; E-mail: iveta.golubovska@tos.lv
** Rīga Stradiņš University, Department of Anaesthesiology and Reanimatology, Dzirciema iela 16, Rīga, LV-1007, LATVIA
Proc. Latvian Acad. Sci., Section B, Vol. 60 (2006), No. 2/3, pp. 70–76.

Chronic low back pain after failed low back surgery is a major health-care and social problem. To assess the therapeutic benefits of repeated epidural steroid injections in patients suffering from chronic low back pain, 30 ASA (American Society of Anaesthesiologists) physical status I and II patients, who had previously undergone spine surgery and received extensive conservative treatment, were enrolled in the study. All patients received Depomedrol (Farmacia-Upjohn) 80 mg with Naropin 0.75% 1 ml and Fentanyl 0.05 mg, in 8 ml 0.9% NaCl, epidurally. Epidural injections were performed three times with two-week interval. The results were compared after conservative treatment, before the first injection, two weeks after the first injection, not earlier than two months after the first injection. All 30 patients completed the study. The study results show marked initial relief in 90% (27 male / 30 female), with excellent and good relief in 50% (15 / 30) of all injected patients, compared to 30% of patients with good and excellent relief after prolonged previous treatment that did not have long-lasting results. Although this is a preliminary study, the fact that the pre-injection treatment period was prolonged with no significant clinical improvement suggests the technique as a valid therapeutic intervention, useful in quick control of pain.

Key words: failed back surgery syndrome, epidural steroid injections.

SECONDARY STRUCTURE OF STURGEON GONADOTROPIN b SUBUNIT ISOFORMS

Henriks Zenkevičs^*, Vija Vose^*, Ilze Vosekalna^**, and Ausma Būcena^*
* Institute of Biology, University of Latvia, Mierā iela 3, Salaspils, LV-2169, Latvia
^** Latvian Institute of Organic Synthesis, Aizkraukles iela 21, Rīga, LV-1006, Latvia
Proc. Latvian Acad. Sci., Section B, Vol. 60 (2006), No. 2/3, pp. 77–80.

Three separate isoforms were isolated from the sturgeon Acipenser güldenstädti Br. gonadotropic hormone b subunit. The individual isoforms differed by molecular charge but demonstrated immunologic identity with the standard b subunit. Comparative analysis of circular dichroism (CD) spectra for the first time showed that the individual b subunit isoforms differed from each other and from the standard b subunit by the secondary structure. Reassociation of the individual isoforms b1–3 with the native a subunit produced three types of different a–b dimeric molecules, immunologically identical with each other and with the standard gonadotropic hormone, while the gonadotropic activity of the dimers, comprising b isoforms, was different and considerably lower than that of the standard hormone. The conclusion was made that the b subunit isoforms with altered conformation and molecular charge may interact with native a subunit to form different a–b heterodimers with modified hormonal activity serving as subtle bioregulators at some specific stages of fish gametogenesis.

Key words: gonadotropic hormone, b subunit, isoforms, reassociated a–b subunits, CD spectra, activity.

ROSEOFUNGIN-INDUCED CATION EFFLUXES IN FROG SKELETAL MUSCLE

Nora Švinka
Institute of Experimental and Clinical Medicine, O. Vācieša iela 4, Rīga, LV-1004, LATVIA
Proc. Latvian Acad. Sci., Section B, Vol. 60 (2006), No. 2/3, pp. 81–84.

Cation efflux induced by polyene antibiotic roseofungin (5x10^–6–10^–4 mol·l^–1) in frog whole sartorius muscles was investigated and compared with that of levorin (10^–6 mol·l^–1). Cation efflux was studied using flame emission photometry. The K⁺ and Rb⁺ effluxes induced by roseofungin were much lower than those induced by levorin. The kinetics of release of polyenes from muscles was studied by removing of the antibiotics from solution. The efflux induced by roseofungin was almost completely reversible whereas levorin-induced efflux was irreversible. Our results indicate low sensitivity of the cholesterol-containing muscle membrane to roseofungin in comparison to levorin. The reversibility of the roseofungin-induced efflux suggests its potential as a medical preparation. The large irreversible levorin effect in the muscle membrane is probably due to a toxic side effect of this antibiotic when used in antifungal therapy.

Key words: cation effluxes, roseofungin, levorin, muscle fibre membrane, antifungal therapy.

LONG-TERM CHANGES OF SNOW COVER IN LATVIA AS INDICATOR OF CLIMATE VARIABILITY

Anita Draveniece, Agrita Briede, Valērijs Rodinovs, and Māris Kļaviņš
Faculty of Geographical and Earth Sciences, University of Latvia, Raiņa bulv. 19, LV-1586, Rīga, Latvia; E-mail: maris.klavins@lu.lv
Proc. Latvian Acad. Sci., Section B, Vol. 60 (2006), No. 2/3, pp. 85–91.

Long-term changes (1945–2004) of snow cover in Latvia were studied using the data from 28 observation sites. Over the territory there are wide spatial differences in snow cover duration: from 70 days in the western part up to 136 days in the uplands of eastern Latvia. A general decrease in snow cover over Latvia has been observed, including an overall decrease of snow cover duration. Both the snow cover depth and duration exhibit not only regional variability, but also a well-pronounced oscillatory pattern. The snow cover, the temperature regime, and the amount of precipitation is very much influenced by large scale atmospheric oscillation over the North Atlantic.

Key words: snow cover, long-term changes, Latvia, NAO index, Baltic winter climate index.

BIRD’S-FOOT-TREIFOIL Lotus L. IN THE FLORA OF LATVIA

Ieva Roze
Institute of Biology, University of Latvia, Miera iela 3, Salaspils, LV-2169, LATVIA; E-mail: iroze@email.lubi.edu.lv
Proc. Latvian Acad. Sci., Section B, Vol. 60 (2006), No. 2/3, pp. 92–97.

This paper provides a revised and detailed nomenclature of the Lotus L. species found in Latvia, describes the most characteristic identifying features of the species, as well as gives species distribution in Latvia (provided with maps). An identification key for the species found in Latvia was developed. In Latvia there are six Lotus species: L. ambiguous Besser ex Spreng, L. arvensis Pers., L. balticus Miniaev, L. callunetorum (Juxip) Miniaev, L. corniculatus L., L. uliginosus Schkuhr.

Key words: Lotus, taxonomy, morphology, habitat, distribution.

CDKN2A MUTATIONS AND LOSS OF HETEROZYGOSITY IN PRIMARY MELANOMAS

Dace Pjanova, Olita Heisele, Ludmila Eņģele* , and Vita Ignatoviča
Latvian Biomedical Research and Study Centre, Rātsupītes ielā 1, Rīga, LV-1067, LATVIA; E-mail: dace@biomed.lu.lv
^* Latvian Oncological Centre, Hipokrāta ielā 4, Rīga, LV-1079, LATVIA
Proc. Latvian Acad. Sci., Section B, Vol. 60 (2006), No. 2/3, pp. 98–100.

Malignant cells from tissue specimens of familial and sporadic melanomas have frequent chromosomal breaks and deletions on chromosome 9p21, a region that includes a tumour suppressor gene CDKN2A. Germline mutations within this gene have been observed in melanoma kindreds. Somatic mutations in sporadic primary melanoma are less frequent. Twenty-seven primary cutaneous malignant melanomas were analysed for mutations in the CDKN2A gene using sequencing and loss of heterozygosity (LOH) of four microsatellite markers on 9p21 was assessed in ten tumours. No CDKN2A mutations were revealed. LOH for at least one microsatellite marker was found in three melanomas (3/10, 30%). These results indicate that intragenic mutations are an infrequent mechanism of CDKN2A inactivation in primary melanomas and suggest that another tumour suppressor gene involved in melanoma is located at 9p21.

Key words: CDKN2A, primary melanoma, mutations, loss of heterozygosity (LOH), polymorphisms.

DIVISION OF PHYSICAL AND TECHNICAL SCIENCES OF THE LATVIAN ACADEMY OF SCIENCES: ACTIVITIES IN 2005

DIVISION OF CHEMICAL, BIOLOGICAL, AND MEDICAL SCIENCES OF THE LATVIAN ACADEMY OF SCIENCES: ACTIVITIES IN 2005

DIVISION OF AGRICULTURE AND FORESTRY SCIENCES OF THE LATVIAN ACADEMY OF SCIENCES: ACTIVITIES IN 2005

JĀNIS SKUJIŅŠ (1926–2005), A LATVIAN SOIL SCIENTIST

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