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Yellow head virus (YHV) is known as a major pathogen in the black tiger shrimp, Penaeus (Penaeus) monodon. It can also cause serious mortality in farmed whiteleg shrimp, Penaeus (Litopenaeus) vannamei. However, there is no published information on the economic and/or production impact of the disease in P. vannamei. Shrimp with gross signs of YHV disease (faded body colour and 60-70% mortality) were observed in 20 study farms rearing P. vannamei in the central part of Thailand from the end of 2007 through early 2008. The estimated economic loss for these farms according to the Thai Animal Aquaculture Association was approximately US$3 million. Detailed sequence analysis of RT-PCR amplicons from shrimp in all the study ponds revealed the presence of YHV Type 1b (YHV-1b) alone (characterized by a 162-bp deletion in the ORF3 region encoding the structural gene for gp116) and the absence of YHV Type 1a (YHV-1a), the original YHV type reported from Thailand. Despite the large 162-bp deletion (= 54 deduced amino acids) in the gp116 structural gene, histopathology of YHV-1b infections was identical to that of YHV-1a infections, and electron microscopy revealed that YHV-1b virions were morphologically indistinguishable from those previously reported for YHV-1a. In addition, an existing commercial RT-PCR detection kit and an immunochromatographic test strip for the detection of YHV were proven to have been valid tests for both YHV-1b and YHV-1a. The source of the virus for these outbreaks was unlikely to have been the post-larvae used to stock the ponds, as they were derived from domesticated specific pathogen-free stocks free of YHV. Thus, it is possible that they originated from an unknown, natural reservoir.

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This was a case of an intrauterine parvoviral B19 infection resulting in hydrops fetalis and enlarged placenta. Histologically, the virus was found to be in nucleated red cells of the fetus which was confirmed by electron microscopy. Careful placental examination at the gross and microscopic levels yielded the correct diagnosis.

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Phaeohyphomycosis caused by Phialophora parasitica is rare and it has never been documented in Thailand. The first two Thai cases of phaeohyphomycosis caused by P. parasitica were recognized in early 1990 at Ramathibodi Hospital, Bangkok, Thailand. Both patients had underlying diseases. The fungus developed in abscesses with pigmented mycelium at the lower extremity. Cultures from pus and tissue biopsies were positive for dematiaceous fungi. Light microscopic features suggested P. parasitica and which was illustrated by both scanning and transmission electron microscope. The first case was treated with itraconazole with a satisfactory initial response. The second case was successfully treated by surgical removal of the entire lesion.

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Hepatopancreatic parvovirus (HPV) causes disease in several species of penaeid shrimp. Heavy infections may result in poor growth and reduced production for shrimp farmers. From one southern Thai shrimp pond with a high prevalence of HPV infection, 790 shrimp were sampled randomly and the hepatopancreas (HP) removed. Most HP were preserved in liquid nitrogen. However, every 10th HP (79 total) was divided into 2 parts appropriately fixed for examination by transmission electron microscopy (TEM) and light microscopy. Based on light microscopy, the prevalence of HPV infection in the pond was approximately 30% and its presence was confirmed by TEM of parallel samples. The virus was subsequently purified from hepatopancreatic homogenates of the samples preserved in liquid nitrogen. Negative staining of the purified viral preparation revealed unenveloped, icosahedral viral particles 22 to 24 nm in diameter. Agarose gel electrophoresis of nucleic acid extracts revealed the presence of 2 fragments, one very intense (5.8 kb) and the other weak (4.2 kb). The larger fragment was degraded by DNase I and S1 nuclease, indicating single-stranded DNA (ssDNA) characteristic of the viral family Parvoviridae. The smaller fragment was degraded by DNase I but not by S1 nuclease, indicating that it comprised double-stranded DNA. A genomic DNA library of the 5.8 kb ssDNA was constructed in pUC18 and a clone containing a 659 bp fragment specific and sensitive for HPV was selected for sequencing. Based on this sequence, an HPV-specific primer set was designed to yield a 156 bp amplicon by polymerase chain reaction (PCR) amplification. The expected 156 bp amplicon was obtained only in the presence of HPV DNA template (at as little as 1 fg purified DNA) and not with nucleic acid templates extracted from healthy shrimp tissue or other shrimp pathogens. It is hoped that this PCR assay will be useful to shrimp aquaculturists for early detection and screening of shrimp larvae, parental broodstock or other possible carriers of HPV in the shrimp cultivation system.

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Various concentrations of isopropyl beta-D-thiogalactopyranoside (IPTG) were used to induce production of the enzyme penicillin G acylase by recombinant Escherichia coli harboring plasmid pQEA11. The plasmid pQEA11 carries a wild-type pga gene, which is under the control of the tac promoter and lacIq. At low IPTG concentrations (0.025-0.1 mM), enzyme activity increased with increasing IPTG concentrations. At higher IPTG concentrations (0.2 and 0.5 mM), enzyme activity declined progressively. Examination of induced recombinant E. coli cells by transmission electron microscopy showed the presence of only periplasmic inclusion bodies at low IPTG concentrations (up to 0.1 mM) and both periplasmic and cytoplasmic inclusion bodies at high IPTG concentrations (0.2 mM and 0.5 mM). Results from sodium dodecyl sulfate/polyacrylamide gel electrophoresis and immunoblots of whole-cell proteins, membrane proteins and inclusion body proteins in these cells indicated that cytoplasmic inclusion bodies constituted an accumulation of preproenzyme (i.e., precursor polypeptide containing a signal peptide) and that periplasmic inclusion bodies constituted an accumulation of proenzyme (i.e., precursor polypeptide lacking a signal peptide).

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A direct comparison of skin Langerhans cell (LC) morphologic change following in vivo and in vitro exposure to dengue-2 (DEN-2) virus (16681) was performed in the monkey to investigate any differences in functional activity profiles. Time-lapse study of skin biopsy at the intradermal (id) virus injection sites, and thin skin sheets removed from the monkey with exposure to virus in culture medium, revealed a highly active migration of epidermal LCs in both sets of experimental specimens. The migration led to a relatively higher number of dendritic cells (DC) which appeared in active migrational profiles, in the superficial dermis. Moreover, obvious cytoplasmic structural changes, corresponding to their immunologic function, were observed in these superficial dermal DCs 2 hours after exposure. Despite their similar changes, early and late endosomes with degraded virus-like particles could be seen in the skin sheets owing to lagging in cellular physiological process in vitro, but none in the skin biopsies. Existence of these endosomes, which was extremely difficult to visualize in vivo, highlighted the mode of antigen processing by the endocytic pathway. The present study showed that the epidermal LC was a potent antigen-presenting cell for eliciting the success of id immunization and carried out the immunological activity in vivo or in vitro in the like manner, in respect to the physiological conditions.

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Using morphology and cytochemical reaction, we could subclassify-according to FAB classification, 51 of our 56 cases of acute nonlymphoblastic leukemia (ANLL) as M1-M5. Five cases were undifferentiated. Using the immunophenotypic method, we could subclassify 51 of these patients as M1-M4. In addition, 3 cases of undifferentiated leukemia by the prior method were each classified as M1, M3, and myelo-megakaryoblastic leukemia. Correlation of ANLL subtype classification according to each method was not good. However, combination of both methods, using immunophenotypic analysis as a supplement would better subclassify the disease. One of the remaining 2 cases of undifferentiated leukemia was also shown to be myelo-megakaryoblastic leukemia by a positive platelet peroxidase reaction by ultrastructural cytochemistry. Thus, combination of these 3 methods could diagnose and subclassify 55 of the 56 cases (98%) of our ANLL patients.

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After the introduction of the dengue-2 (16681) virus by intradermal (i.d.) injection into the footpads of mice, Langerhans cells (LCs) increased in numbers within 24 h at the site of injection and neutralising antibody developed. On comparing the i.d. and intramuscular (i.m.) routes, antibody was produced more rapidly and at higher levels when the virus was injected by the i.d. route. Subsequent re-challenge by the i.d. route produced an even more rapid serological response with all mice producing significant neutralising titres within 12 h. Numbers of ATPase-positive LCs varied with time. A significant sharp drop in LC densities in the early post-injection phase directly correlated with the increased numbers of dendritic cells in the superficial dermis and interfollicular sinuses of draining lymph nodes (LN). Immunofluorescence showed the presence of viral antigen in the footpad epidermis and draining LN within minutes or within 2 h of challenge, respectively.

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The ultrastructure of a cholangiocarcinoma cell line (HuCCA-l) originally established from an intrahepatic bile duct tumor of a patient seropositive for a liver fluke infection was studied by scanning (SEM) and transmission (TEM) electron miscroscopy. With the SEM, the surface of HuCCA-1 cells were found to be covered with microvilli. The size of these microvilli varied from cell to cell and they were irregularly distributed. The TEM clearly revealed the presence of cytokeratin filaments, an intracytoplasmic lumen, tight junctions at the apices and desmosomes at the lateral surfaces of neighboring cells, all of which are characteristics of adenocarcinoma cell origin. However, the tumor mass that developed in a nude mouse following subcutaneous injection of these cells was found to exhibit some morphological changes. Specifically, about 20-30% of the tumor cells, particularly those lining the base of the tumor tubules, exhibited electron dense tonofilaments typical of squamous cells. However, this alteration was reversible as the cell line (HuCCA-1Nu) derived from this nude mouse-passage did not exhibit any characteristics reminiscent of squamous cells. These observations are consistent with those occasionally found in human cases reported previously by other investigators. Altogether, the data showed that squamous transformation of adenocarcinoma cells can occur under appropriate conditions. It further showed that reversion to adenocarcinoma cells can occur when the microenvironment is changed.

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In a study of twenty-seven patients with partial thickness burn wound, they were treated with aloe vera gel compared with vaseline gauze. It revealed the aloe vera gel treated lesion healed faster than the vaseline gauze area. The average time of healing in the aloe gel area was 11.89 days and 18.19 days for the vaseline gauze treated wound. Statistical analysis by using t-test and the value of P < 0.002 was statistically significant. In histologic study, it showed early epithelialization in the treated aloe vera gel area. Only some minor adverse effects, such as discomfort and pain were encountered in the 27 cases. This study showed the effectiveness of aloe vera gel on a partial thickness burn wound, and it might be beneficial to do further trials on burn wounds.

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Cholangiocarcinoma (CCA) is a relatively rare tumor that occurs primarily in tropical countries and particularly in those with a high incidence of liver fluke infection. A hamster model for a liver fluke-associated CCA has been described previously. In the present study, hamster cholangiocarcinoma cell lines were established and characterized in order to obtain information regarding diagnostically useful tumor marker which could shed light for a future investigation for human cholangiocarcinoma. Two related cell lines, one from the original intrahepatic bile duct tumor and one from an allotransplanted tumor, were established. The established cell lines were found to have population doubling times of 31 and 26 hours respectively, and were maintained in Ham's F12 medium supplemented with 10% fetal bovine serum for over 80 passages. The cell monolayers were subjected to scanning and transmission electron microscopic study and found to have ultrastructural characteristics, including cytoplasmic lumens, consistent with those of adenocarcinoma cells of epithelial origin. An immunoperoxidase study using monoclonal antibodies (MAbs) specific for tumor antigens showed the cytoplasm and membrane of both cell lines to be positive. These antigens were also secreted in soluble form into the culture medium, judging from polyacrylamide gel electrophoresis in the presence of SDS and from immunoblot analyses. Different lines of evidence presented suggested that a 200 kDa glycoprotein produced and secreted by the tumor cell lines could be considered a cholangiocarcinoma-associated marker which has diagnostic potential.

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Platelets from patients with beta-thalassemia/hemoglobin E, both splenectomized and nonsplenectomized cases, were examined in comparison to those from normal subjects by scanning electron microscopy. In normal subjects, the majority of platelets were discoid (mean +/- SD, 81.0 +/- 3.9%) with 17.3 +/- 3.5% type I spherical shapes (platelet with long axis/short axis greater than 1.1) and 1.3 +/- 1.0% type II (long axis/short axis = 1.0-1.1). The thalassemic patients had significant lower percentage of discoid platelets (60.9 +/- 8.1% in nonsplenectomized patients, 49.2 +/- 9.1% in splenectomized patients) and increase in spherical platelets (nonsplenectomized patients had 36.6 +/- 8.3% type I, 4.0 +/- 1.5% type II; splenectomized patients had 43.4 +/- 7.9% type I, 8.3 +/- 4.5% type II). Study of platelet reversibility from pseudopods to smooth surface showed that thalassemic platelets had poorer reversibility than normal platelets. Splenectomized patients had lower platelet pseudopod reversibility than nonsplenectomized cases. The shape changes and impaired reversibility of platelet pseudopods may be associated with the high tendency of pulmonary thrombus in beta-thal/HbE patients.

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We could identify, via bronchoalveolar lavage, crystals in the lavage fluid and in the alveolar macrophages. Thus, BAL could be another method for diagnosing silicosis patients.

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Cytochalasin E increased the vascular permeability in the dermis of one-day-old mouse. It simultaneously induced edema and erythema as resulted from the leakage of plasma and red blood cells through the intercellular gaps of endothelial cells in both capillaries and venules. Meanwhile, there was a markedly decrease in plasma protein transport via pinocytotic vesicles.

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