X-ray Sensitivity of HeLa S3 Cells in the G2 Phase: Comparison of Two Methods of Synchronization

The sensitivity of HeLa S3 cells to 220 kv X-rays was measured in terms of cell survival (colony development) during the G2 phase of the cell generation cycle, employing two procedures designed to free G2 cultures from contaminating cells from other phases of the cycle. Treatment of synchronous cultures (obtained initially by mitotic selection) with high specific activity tritiated thymidine (HSA-³HTdR) selectively eliminated S phase cells, while addition of vinblastine permitted removal of cells as they entered mitosis. It was found that HeLa S3 cells become increasingly sensitive as they progress through G2. The pattern of sensitivity fluctuations observed in synchronous HeLa S3 populations selected by the foregoing method was compared with that found in synchronous cultures prepared by the HSA-³HTdR method of Whitmore. The latter method had been used previously with mouse L cells, which were found to undergo a different pattern of sensitivity fluctuations. The two methods yield similar results for HeLa cells in the S and G2 phases of the cycle. It may be concluded, therefore, that the discrepancies between HeLa and mouse L cells do not arise from methodological factors, but represent fundamental differences between the cell types.     

Rhabditophanes schneideri (Rhabditida) phoretic on a cave pseudoscorpion

Information of phoretic nematode-pseudoscorpion associations and cases of parasitism on five European species of pseudoscorpions was summarized by Cur?ic et al. [Curci?, B.P.M., Dimitrijevi?, R.N., Makarov, S.E., Luci?, L.R., Curci?, S.B., 1996. Further report on nematode-pseudoscorpion associations. Acta arachnol. 45, 43-46; Curci?, B.P.M., Sudhaus, W., Dimitrijevi?, R.N., Tomi?, V.T., Curci?, S.B., 2004. Phoresy of Rhabditophanes schneideri (Bütschli) (Rhabditida: Alloionematidae) on pseudoscorpions (Arachnida: Pseudoscorpiones). Nematology 6 (3), 313-317]. An examination of a sample of the cavernicolous pseudoscorpion Neobisium rajkodimitrijevici (Curci? and Tomi?, 2006) (comprising a holotype male and a paratype tritonymph) from a cave in Eastern Serbia revealed this false scorpion to be a nematode carrier; the present paper reports this finding and extends our knowledge of phoresy of Rhabditophanes on pseudoscorpions. This is the first time that the rhabditid R. schneideri (Bütschli, 1873) has been noted in association with a cavernicolous pseudoscorpion. There must be some patchily distributed micro-habitats in caves where saprobiotic nematodes and small arthropods can complete their life-cycles, for example something like deposits of bat guano. The transportation of Rhabditophanes J3 by pseudoscorpions indicate that Neobisium specimens often visit these micro-habitats to find their prey.     

Tools for comparative protein structure modeling and analysis

The following resources for comparative protein structure modeling and analysis are described (http://salilab.org): MODELLER, a program for comparative modeling by satisfaction of spatial restraints; MODWEB, a web server for automated comparative modeling that relies on PSI-BLAST, IMPALA and MODELLER; MODLOOP, a web server for automated loop modeling that relies on MODELLER; MOULDER, a CPU intensive protocol of MODWEB for building comparative models based on distant known structures; MODBASE, a comprehensive database of annotated comparative models for all sequences detectably related to a known structure; MODVIEW, a Netscape plugin for Linux that integrates viewing of multiple sequences and structures; and SNPWEB, a web server for structure-based prediction of the functional impact of a single amino acid substitution.     

Ultraviolet sun radiation and incidence of age-related macular degeneration on Croatian Island Rab

This epidemiological study is completed on island Rab, located in North Adriatic Sea. For this study it is important that Adriatic Sea has one of the highest solar radiations in geographical area of Europe. The aim of this epidemiological study is to estimate correlation between incidence of Age-Related Macular Degeneration (AMD) and exposure of sunlight in two different populations on island Rab. In the first group of population of island Rab, agriculturists and fishermen (n = 1300), incidence of AMD was in 18%, but in urban population only 2.5%. It is very interesting that correlation exists between incidence of AMD and exfoliation syndrome. In the group of chronic exposure to sunlight (agriculturists and fishermen) exfoliation syndrome exists in 28%, but in urban population it has never been seen. The age in both populations was 45-65 years. We can conclude that there is a very significant correlation between chronic exposure to sunlight and appearance of AMD.     

Endoplasmic reticulum retention of the gamma-secretase complex component Pen2 by Rer1

gamma-Secretase is involved in the production of amyloid beta-peptide, which is the principal component of amyloid plaques in the brains of patients with Alzheimer disease. gamma-Secretase is a complex composed of presenilin (PS), nicastrin, anterior pharynx-defective phenotype 1 (Aph1) and PS enhancer 2 (Pen2). We previously proposed a mechanism of complex assembly by which unassembled subunits are retained in the endoplasmic reticulum (ER) and only the fully assembled complex is exported from the ER. We have now identified Retention in endoplasmic reticulum 1 (Rer1) as a protein that is involved in the retention/retrieval of unassembled Pen2 to the ER. Direct binding of unassembled Pen2 to Rer1 is mediated by the first transmembrane domain of Pen2, and a conserved asparagine in this domain is required. Downregulation of Rer1 leads to increased surface localization of Pen2, whereas overexpression of Rer1 stabilizes unassembled Pen2. To our knowledge, Rer1 is the first identified interaction partner of mammalian transmembrane-based retention/retrieval signals.     

Ecphylus silesiacus (Ratz.) (Hymenoptera, Braconidae), an important elm bark beetle parasitoid

1 Ecphylus silesiacus (Ratz.) (Hym. Braconidae) parasitizes larvae of elm bark beetles (Coleoptera: Scolytidae) occurring in thin bark. Pteleobius kraatzi (Eichh.), Scolytus pygmaeus (Fab.), Scolytus multistriatus (Marsh) and Scolytus ensifer (Eichh.) are the most suitable hosts. Scolytus scolytus (Fab.) occurring in thicker bark, is not such a suitable host for E. silesiacus. Ecphylus silesiacus only parasitized this species in bark forks. 2 Under experimental conditions, P. kraatzi produced the largest number of elm bark beetle adults per maternal gallery and had the longest development period, while S. scolytus produced the smallest number of adults and had the shortest development period. 3 Ecphylus silesiacus had the lowest reproduction, the shortest development period and the least favourable sexual ratio, on S. scolytus larvae, and the highest production, the longest developmental period and the most favourable sexual ratio on P. kraatzi and S. pygmaeus larvae. 4 Ecphylus silesiacus adults fed with Parker's diet and the nectar of the melliferous plant Daucus carota L. (Umbelliferae), lived longer, parasitized a greater percentage of S. pygmaeus larvae, and had a significant offspring production compared with adults without additional diet.     

Tacrolimus (FK506) Prevents Early Stages of Ethanol Induced Hepatic Fibrosis by Targeting LARP6 Dependent Mechanism of Collagen Synthesis

Tacrolimus (FK506) is a widely used immunosuppressive drug. Its effects on hepatic fibrosis have been controversial and attributed to immunosuppression. We show that in vitro FK506, inhibited synthesis of type I collagen polypeptides, without affecting expression of collagen mRNAs. In vivo, administration of FK506 at a dose of 4 mg/kg completely prevented development of alcohol/carbon tetrachloride induced liver fibrosis in rats. Activation of hepatic stellate cells (HSCs) was absent in the FK506 treated livers and expression of collagen α2(I) mRNA was at normal levels. Collagen α1(I) mRNA was increased in the FK506 treated livers, but this mRNA was not translated into α1(I) polypeptide. No significant inflammation was associated with the fibrosis model used. FK506 binding protein 3 (FKBP3) is one of cellular proteins which binds FK506 with high affinity. We discovered that FKBP3 interacts with LARP6 and LARP6 is the major regulator of translation and stability of collagen mRNAs. In the presence of FK506 the interaction between FKBP3 and LARP6 is weakened and so is the pull down of collagen mRNAs with FKBP3. We postulate that FK506 inactivates FKBP3 and that lack of interaction of LARP6 and FKBP3 results in aberrant translation of collagen mRNAs and prevention of fibrosis. This is the first report of such activity of FK506 and may renew the interest in using this drug to alleviate hepatic fibrosis.     

Database of sentences of Croatian language

The aim of this paper is to investigate morphological and syntactical levels of sentences of Croatian Language. Morphological grammatical level is represented by 16 categories and 47 features with theirs value. Syntactical level is represented with constituent structure trees of sentences. Database has 1001 grammatical sentences of Croatian literature. Database of sentences is the result of theoretical research in computational linguistics. This study extends the analysis of the linguistic data in anthropology in Croatian. Access to database is through the Internet on the address: http://infoz.ffzg.hr/tepes.     

Early cancer in congenital choledochal cyst

We report a case of 35-yr-old woman with early cancer in congenital choledochal cyst. She had a five-year history of intermittent right upper abdominal pain and intermittent jaundice. In this period she had a few abdominal ultrasonographies, but the cholelithiasis had not been found. Now, she was admitted to our hospital because she felt right upper abdominal pain with slight jaundice and subfebrile temperature four weeks ago. Abdominal ultrasonography showed enormous dilatation of the common bile duct, which was suspected as choledochal cyst. Computed tomography and endoscopic retrograde cholangiopancreatography revealed cystic dilatation of extrahepatic bile duct. An anomalous pancreaticobiliary junction was not found. The patient with congenital choledochal cyst was operated on. The excision of choledochal cyst was done with hepaticojejunostomy Roux-en-Y. There were no lymph nodes metastases. On the central part of choledochal cysts mucosa, it was shown a white plain area of thickness 0.3 cm and 0.8 cm in diameter. Histologically it was well-differentiated tubular adenocarcinoma, which was limited to the mucosa and which did not penetrate to other parts of the bile duct wall. From our knowledge, only small number cases of early cholangiocarcinoma in choledochal cyst were until now reported. Nearly eight years after the operation the patient feels very well, and has optimal working ability (Karnofsky 100%).     

Recurrent pleomorphic adenoma of epipharynx following irradiation therapy

We present a case of a 67-year-old female patient having a pleomorphic adenoma of epipharynx with intact fibrous capsula, which despite its benignity recurred and, moreover, responded quite well to irradiation therapy. The patient, at first, refused any therapy. Three years later, when the CT showed tumor enlargement she accepted only irradiation therapy, resulting in significant reduction of tumor size. Five years later the tumor recurred but without malignant transformation. She still refused surgery, but accepted re-irradiation therapy. After a three-year follow-up the patient has no symptoms of the tumor enlargement. This case shows that the irradiation therapy might be quite effective in the treatment of pleomorphic adenoma of epipharynx, but it is clear that much better results could be accomplished in combination with the surgery. In cases when the surgery is rejected or not possible because of the vicinity of the vital structures, we recommend the irradiation therapy as a therapy of the choice.