Histopathology of paracoccidioidomycotic infection in athymic and euthymic mice: a sequential study

We report the comparative and sequential histologic analysis of lesions developed by Paracoccidioides brasiliensis-infected athymic and euthymic BALB/c mice, using conventional and specific stain to characterize the morphology of fungi and inflammatory cells as well as the extracellular matrix patterns. In both groups, neutrophils and macrophages were the predominant cells; macrophage transition to giant and epithelioid cells was observed. Degenerated fungi and fungal dust were associated with local neutropil infiltration and the presence of pseudoxantomatous macrophages. Paracoccidioides brasiliensis are always found within an extracellular matrix microenvironment. The main differences between lesions developed by nu/+ and nude (nu/nu) mice resided in the more pronounced encapsulating tendency in the former ones. In both groups of animals, lesions in several organs were associated with extensive hemopoiesis. At the first week of infection, there was evidence of fungal destruction and control of its proliferation in both mouse groups. At the fourth and seventh weeks, nu/+ mice maintained the control of the infection, as shown by the scarce numbers of budding yeast cells, while experimental nu/nu mice showed a tumor-like progression of the disease with a striking increase in fungal load in many organs (e.g., omental and mesenteric milky spots, lymph nodes, spleen), some of which present their structure replaced by granulomatous lesions.

Single application extracorporeal shock wave lithotripsy is the first choice for patients with pancreatic duct stones

OBJECTIVES

We performed extracorporeal shock wave lithotripsy (ESWL) as the treatment of first choice on 32 chronic pancreatitis patients with main pancreatic duct (MPD) stones prospectively to establish more convenient and safer treatment.

METHODS

All patients were treated in a prone position, and shock waves were discharged from the ventral side. ESWL was performed once or twice a week, and no other treatments before ESWL had been applied.

RESULTS

Disintegration of all MPD stones to 3 mm or less in diameter could be achieved in all treated patients. Complete clearance of the stones was obtained in 24 patients (75%) without the necessity of endoscopic extraction of fragments. Reduction of MPD diameters after ESWL was statistically significant (p < 0.01). Epigastric and/or back pain complaints before ESWL were completely alleviated in 79% (periods of follow-up: 16-63 months, mean 44), and the pancreatic exocrine function also improved in 61%. No severe complications occurred in any of the patients.

CONCLUSIONS

ESWL, which is comparatively easy to perform, is a safe and efficient approach that changes endoscopy's status as an indispensable pretreatment. Therefore, ESWL can be recommended as the first choice treatment for patients with chronic pancreatitis accompanied by MPD stones that should be tried before consideration of either surgical or endoscopic procedures.

[A case of advanced gastric cancer with liver metastasis with no recurrence and long survival]

A 61-year-old male was admitted after detecting gastric lesion by gastrography in a medical health examination. The patient was diagnosed as Borrmann 2 advanced gastric cancer with remarkable intraperitoneal lymph node metastasis and liver tumor of lateral segment. Relative non-curative gastrectomy was performed with combined partial hepatectomy. The liver tumor measured 1.5 x 1.5 cm and was intraoperatively diagnosed as metastasis of gastric cancer. Mitomycin C 26 mg was given intravenously on the day of operation and 5-fluorouracil (5-FU) 150 mg/day orally since postoperative 14th day as adjuvant chemotherapy. The administration of 5-FU was continued for 5 years. As a result of such combination therapy, the patient still has had no recurrence 8 years following operation.

Phylogeny of Epidermophyton floccosum and other dermatophytes

Eleven strains of Epidermophyton floccosum were compared with 5 Microsporum and 5 Trichophyton species with respect to the restriction fragment length polymorphism (RFLP) of the mitochondrial DNA to reveal their phylogenetic relationships. The phylogeny of 11 species showed that the three dermatophyte genera could not be separated from each other and could be considered to be congeneric. This result is not inconsistent with the results from ribosomal RNA sequences.

Bile secretion in rats with indomethacin-induced intestinal inflammation

The objective of this study was to characterize the bile secretion, including the composition of biliary bile acids, bile salt pool size, and transcytotic vesicle transport, in a rat model of subacute intestinal inflammation induced by indomethacin. Indomethacin treatment significantly decreased bile acid-independent bile flow and biliary secretion of bile acid and cholesterol, while increasing biliary phospholipid output in vivo. Although indomethacin treatment did not change the bile salt pool size in vivo, alpha- and beta-muricholic acids were significantly deceased and hyodeoxycholic and deoxycholic acids were increased in bile. Bile flow and the transport maximum of taurocholate did not decrease, and biliary horseradish peroxidase output was significantly enhanced in isolated perfused livers from indomethacin-treated rats. Endotoxin in the portal blood was significantly increased in rats treated with indomethacin. Clindamycin slightly reduced intestinal inflammation but significantly prevented decreases in bile flow, bile acid output, and transport maximum of taurocholate. We conclude that, although biliary secretory function was apparently decreased in vivo, that of hepatocyte function was maintained in this model.

A new type of growth exhibited by Trimmatostroma abietis

Trimmatostroma abietis initially grew as hyphae when grown in various media containing yeast extract or bactopeptone. It grew as segmented elements (lumbricoid elements) characterized by bidirectional growth, when grown in Czapek-Dox broth or yeast nitrogen base supplemented with 1% glucose. A lumbricoid element usually was 10-70 microns in length, with transverse septation only and contained 3 to 15 cells. Growth and propagation, as revealed by time-lapse photomicrography occurred as follows. Elements usually grew by apical elongation without widening; after simple apical elongation adjacent parts of two central cells eventually started to grow, resulting in the separation of the element into two.

Mitochondrial DNA analysis of Sporothrix schenckii in Costa Rica

Mitochondrial DNA (mtDNA) types using restriction patterns with HaeIII were investigated in 21 clinical isolates of Sporothrix schenckii in Costa Rica. Nineteen isolates were found to be a new mtDNA type (Type 14), while the remaining two were Type 3 and Type 6. Based on the phylogeny of 14 mtDNA types constructed by estimating sequence divergences of mtDNA, S. schenckii were clustered into two main groups: Group A and Group B, with Type 14 and Type 3 included in Group A, and Type 6 in Group B. The results suggest that isolates of Group A may exist mainly in Central America including Costa Rica.

Different rifampicin inactivation mechanisms in Nocardia and related taxa

Mycolic acid-containing bacteria inactivate rifampicin in a variety of ways such as glucosylation, ribosylation, phosphorylation and decolorization. These inactivations were found to be a species-specific phenomena in Nocardia and related taxa. Gordona, Tsukamurella and fast-growing Mycobacterium modified rifampicin by ribosylation of the 23-OH group of the antibiotic. Such ribosylation was not observed in Rhodococcus and Corynebacterium, but phosphorylation of the 21-OH group of rifampicin was observed in one strain of Rhodococcus. Nocardia modified the antibiotic by glucosylation (23-OH group) and phosphorylation, but ribosylation was not observed.

Effect of methyl linoleate hydroperoxides on murine natural killer cell-mediated cytotoxicity

Methyl linoleate hydroperoxides (MLHPO), a model for lipid hydroperoxides, suppressed murine natural killer (NK) cell-mediated cytotoxicity to YAC-1 cells. When NK cells were cultured with MLHPO, the conjugation of NK cells could not lyse YAC-1 cells. These findings suggest that NK cell-mediated cytotoxicity can be suppressed by lipid hydroperoxides.

Cell-surface hydrophobicity and lipolysis as essential factors in human tinea nigra

Hydrophobic adhesion of cells of the black yeast Hortaea werneckii (Horta) Nishimura & Miyaji, causative agent of human tinea nigra, was established by microbial adhesion to hexadecane (MATH) and adhesion to polystyrene, and compared with adhesion of other species of black yeasts. Additional ecophysiological tests were performed. Hortaea werneckii cells proved to have a high degree of hydrophobicity (98.5% MATH). The species is unable to degrade keratin, but shows significant lipolytic activity. It is concluded that H. werneckii is a commensal, that shows lipophilic adhesion to human skin and survives by the assimilation of excretion products.

A human isolate of Exophiala (Wangiella) dermatitidis forming a catenate synanamorph that links the genera Exophiala and Cladophialophora

A strain of the black yeast Exophiala dermatitidis displayed a hydrophobic synanamorph consisting of acropetal chains of lemon-shaped conidia, morphologically similar to those of Cladophialophora bantiana. The occurrence of the two conidial types in a single strain suggests a taxonomic affinity between Exophiala and Cladophialophora and provides support to the supposition that Cladophialophora, a possible anamorph genus of Herpotrichiellaceae, is related to black yeasts rather than to Cladosporium, which has teleomorphs in the Mycosphaerellaceae.

Mitochondrial DNA analysis of Exophiala spinifera

Restriction fragment length polymorphism (RFLP) of mitochondrial DNA (mtDNA) was examined in 36 isolates of Exophiala spinifera (8 isolates from Brazil, 9 from China, 15 from Columbia, 1 from the United States and 2 from Venezuela). E. spinifera isolates displayed a high degree of mtDNA diversity in RFLP patterns and were clustered into six genetically heterogeneous groups (Group 1 through Group 6). Isolates of Group 2 including the type strain seemed to have a worldwide distribution. RFLP patterns of E. spinifera were also distinct from those of other dematiaceous fungi, such as E. jeanselmei, E. moniliae, E. dermatitidis, Fonsecaea pedrosoi, Cladosporium carrionii and Phialophora verrucosa. These results indicate that E. spinifera may be a taxonomic complex and that RFLP patterns will be useful in the identification, typing and epidemiology of the E. spinifera variants.

Rifampicin inactivation by Bacillus species

The ability of strains of Bacillus, Staphylococcus, Pseudomonas, and Escherichia coli to inactivate rifampicin was tested. Most Bacillus strains were found to inactivate rifampicin. Two modes of inactivation were identified; one was phosphorylation and the other involved decolorization. Presence or absence of either mechanism appeared unrelated to the phylogenetic relatedness of strains. None of the other organisms could inactivate this antibiotic.

Conidial surface ultrastructure of human-pathogenic and saprobic Cladosporium species

Freeze-fracturing of outer wall layers of Cladosporium conidia revealed two types of ultrastructure, coinciding with taxonomic characteristics. The outer conidial layers were essentially smooth in the human pathogenic species, C. bantianum, C. carrionii, and C. trichoides. In contrast, mosaic arrays of rodlets on conidia were observed with freeze-fracturing in the saprobic species, C. cladosporioides, C. coralloides, C. herbarum, C. sphaerospermum, and C. variabile. Conidia of C. elatum were an exception among the saprobic species as they had smooth surfaces. The present study supports the suggestion that the human pathogenic Cladosporium species should be transferred to another genus.

Unbudded G2 as well as G1 arrest in the stationary phase of the basidiomycetous yeast Cryptococcus neoformans

Stationary-phase cells of Cryptococcus neoformans displayed two morphological characteristics: virtually all the cells were unbudded even in the early stationary phase and even when grown in rich media, and average cell size increased from that of exponential-phase cells. DNA contents for small and large stationary-phase cells were determined by quantitative fluorescence microscopy after DNA staining with propidium iodide or DAPI. Small cells contained G1 DNA, whereas large unbudded cells had either a G2 or G1 DNA content, indicating that Cr. neoformans can enter into the stationary phase from either the G1 or G2 period.

[An outbreak of acute pulmonary histoplasmosis among travelers to a bat-inhabited cave in Brazil]

Histoplasmosis is known to be endemic in various parts of the world, especially in North and Latin America. In Japan, Histoplasma capsulatum has rarely been isolated from the natural environment. To date, only seven cases of histoplasmosis have been reported in Japan including some that were contracted in foreign countries. Herein, we report the occurrence of acute histoplasmosis among Japanese travelers who were exposed to bat guano in a cave near Manaus, Brazil. A group of 8 Japanese travelers entered a cave for a total of 2 hours in March, 1993. All the visitors had been healthy and had no history of abnormal chest roentgenograms. From 10 to 20 days after the exposure, 7 (87.5%) of the 8 individuals developed abnormal symptoms including fever, malaise, loss of appetite, myalgia, arthralgia, chest pain and dry cough. Five (62.5%) had nodular infiltrative shadows with or without hilar lymphadenopathy in the chest roentgenograms. Eight (100%) of the individuals showed serologic evidence of histoplasmosis. Despite the small number of subjects, this high rate of infection may be related to the fact that the subjects stayed in an enclosed area where air exchange was minimal, at the end of a deep cave infested with numerous bats. The cave involved has never been documented as being endemic for histoplasmosis. The threat of H. capsulatum infection in bat-inhabited caves should be emphasized to travelers and also to physicians.

Ribosylation by mycobacterial strains as a new mechanism of rifampin inactivation

Several fast-growing Mycobacterium strains were found to inactivate rifampin. Two inactivated compounds (RIP-Ma and RIP-Mb) produced by these organisms were different from previously reported derivatives, i.e., phosphorylated or glucosylated derivatives, of the antibiotic. The structures of RIP-Ma and RIP-Mb were determined to be those of 3-formyl-23-[O-(alpha-D-ribofuranosyl)]rifamycin SV and 23-[O-(alpha-D-ribofuranosyl)]rifampin, respectively. To our knowledge, this is the first known example of ribosylation as a mechanism of antibiotic inactivation.

Comparative studies on bile flow and biliary lipid excretion after bile-acid loading in normal and partially hepatectomized rats

This study was performed to investigate sequential changes in bile secretion and biliary lipids after taurocholic acid (TCA) loading of regenerating rat liver. TCA was administered intravenously at stepwise-increasing doses to groups of non-operated control and partially hepatectomized rats, 24, 72 and 168 h after surgery. Bile flow, bile-acid output (BAO) and phospholipid output (PLO) (expressed per gram of liver) in partially hepatectomized rats increased more than in the controls. Using an isolated perfusion rat-liver system, TCA infusion was also carried out on groups of non-operated control and hepatectomized rats 72 h after operation. Again bile flow, BAO and PLO (expressed per gram of liver) were significantly higher in the partial hepatectomy case, mirroring the results obtained in vivo. When horseradish peroxidase (HRP) was pulse-loaded in isolated perfusion preparations, the second peak of biliary HRP secretion in hepatectomized rats was significantly higher than in controls. We conclude that increased bile-acid flow in partially hepatectomized rats is dependent upon acceleration of vesicular transport accompanying or following proliferation in regenerating livers.

[Two cases of thymic cyst]

Thymic cysts were diagnosed by thoracotomy in two women with leprosy, both 64 years old, within 12 months. Both were asymptomatic and an abnormal mediastinal shadow on an annual screening chest radiograph was a clue to the diagnosis in both cases. According to retrospective studies it took at least six or seven years for the thymic cysts to become large enough to be detected. Real-time echography was effective in the diagnosis of a cystic lesion in one case. Thymic cysts are important cystic lesions rarely found in the anterior mediastinum. A resective operation is thought to be indispensable to differentiate them from thymomas accompanied by large cystic degeneration and from thymic cysts accompanied by malignancies.