Growth inhibition of Blastomyces dermatitidis in alveolar and peripheral macrophages from patients with blastomycosis

Blastomyces dermatitidis evokes a pyogranulomatous disorder with organisms frequently found inside giant cells. Macrophages from bronchoalveolar lavage fluid and peripheral blood in monolayer cell cultures were challenged with live yeast organisms to examine phagocytosis and intracellular growth. A greater number of macrophages from patients recovering from blastomycosis had phagocytized Blastomyces compared with macrophages from healthy control donors. No differences were detected within the groups between alveolar and peripheral macrophages. Intracellular growth of the fungus was reduced in cultures of both cell types from patients compared with those from control subjects. Supernatants from specific Blastomyces antigen-stimulated lymphocyte cultures were collected, and treatment with the supernatant to control donors' macrophages resulted in increased phagocytosis and inhibition of intracellular growth. Antigen-induced lymphocyte stimulation as a correlate of cellular immunity is qualitatively related to alveolar or peripheral macrophage phagocytosis and growth inhibition of this fungus.     

Divergent patterns of pulmonary blastomycosis induced by conidia and yeasts in athymic and euthymic mice

Athymic nude (nu/nu) mice are uniformly more susceptible than euthymic nu/+ mice to lethal infection with intranasally inoculated Blastomyces dermatitidis, whether infection is initiated by yeasts or conidia. Conidial infection requires a high inoculum size; the disease produced is prolonged and disseminated. Yeasts are infective at a low inoculum size and produce a rapidly fatal pneumonia. Thymus transplantation is more protective for conidia-infected than yeast-infected nude mice, presumably because the disease course is long enough for an effect to become demonstrable. Yeast inocula multiply more rapidly in the lungs than do conidial inocula. This may relate to the greater susceptibility of conidia to heterophils evoked in the airways, and the fact that yeasts derived from conidial inocula must survive in the face of an established inflammatory reaction. When yeasts and conidia are inoculated simultaneously, the disease produced is less severe than when yeasts are inoculated alone, presumably because of a more intense and diffuse inflammatory response engendered by the conidia. Suppression of conidia-derived yeast replication is demonstrable for at least 1 wk in nu/nu mice and for 2 to 3 wk in nu/+ mice. The latter delay appears attributable to the intact immune system in nu/+ mice, and the probability that cellular immunity limits the subsequent replication of yeasts. Eventually, the immune response fails to control yeast replication, and the mice succumb. These studies provide further insights into the role of the thymus in host defense against B. dermatitidis and the basis for the differential pace of infection when mice are infected with yeasts or conidia.     

Characteristics of the pulmonary cellular immune response to two strains of Blastomyces dermatitidis in the mouse

In order to assess the cellular responses in the lung in murine pulmonary blastomycosis, serial lung lavages were performed in normal BALB/cByJ mice that had received an intranasal inoculation with 1 of 2 strains of Blastomyces dermatitidis of opposite virulence. The virulent strain, ATCC 26199, induced an increasing number of neutrophils recovered from the lung lavages. An early peak of incoming neutrophils was seen at 1 to 2 days, followed by a more rapid accumulation of intraalveolar neutrophils, until by the ninth day after infection, 80% of the cells recovered from the mice were neutrophils. In contrast, the avirulent strain, ATCC 26197, induced the same degree (20%) of neutrophil influx on Days 1 and 2. Thereafter, the percentage of neutrophils consistently declined, so that by Day 6 after inoculation, the differential counts were normal. The total number of cells recovered from the mice challenged with the virulent strain did not increase significantly until Day 4; then the total number of cells consistently increased until the experiment was terminated on Day 14. The total number of cells obtained from the mice challenged with the avirulent organism never exceeded the normal range. To assess the effects of nonviable inert particles, mice were given Sephadex G-25 beads by the intranasal route, and the total number of cells recovered from the lung lavage fluid and the differential counts were determined. The peak neutrophil influx occurred 6 h after aspiration of the beads, compared with 24 to 48 h with the fungi.(ABSTRACT TRUNCATED AT 250 WORDS)     

Two outbreaks of blastomycosis along rivers in Wisconsin. Isolation of Blastomyces dermatitidis from riverbank soil and evidence of its transmission along waterways

Blastomycosis cannot yet be prevented or controlled, in part because the natural habitat of the causative fungus, Blastomyces dermatitidis, remains ill defined. In investigating 2 outbreaks of blastomycosis that occurred in the summer of 1985 among persons engaged in activities along rivers in contiguous central Wisconsin counties, we isolated B. dermatitidis from soil at one of the riverbanks. Blastomycosis developed in 7 (58%) of 12 residents and guests who had gathered at a pheasant farm on the Tomorrow River in early May, and in 7 (88%) of 8 boys and 1 adult who had visited a site on the Crystal River in early June. Of the 14 patients, 13 (93%) were symptomatic. Two patients visiting the sites only once became ill 23 and 78 days after exposure, respectively. We traced one outbreak to fishing from the bank of the Tomorrow River, and the other to climbing into an underground timber fort along the Crystal River. A culture of soil and organic debris from the fishing site yielded B. dermatitidis. From these and other outbreaks, and studies of endemic disease, we conclude that riverbanks can be a natural habitat of B. dermatitidis, and that the environment around waterways represents the most important site yet identified for transmission of B. dermatitidis.     

Lectin-like attachment sites on murine pulmonary alveolar macrophages bind Aspergillus fumigatus conidia

Murine pulmonary alveolar macrophages bound Aspergillus fumigatus conidia in vitro at 4 C and 37 C in the absence of serum or opsonins. This attachment was dependent on calcium and was sensitive to mild trypsinization and paraformaldehyde pretreatment of the macrophage membrane. Chitotriose, N-acetylglucosamine, D-mannose, alpha-methyl-mannoside, and L-fucose, but not D-galactose, were effective inhibitors of conidial binding. This pattern of reduction of conidial binding was consistent with that for the mannosylfucosyl receptor. In addition, conidial binding may be mediated by another lectin on the macrophage membrane, one that recognizes chitin components, because N-acetylglucosamine and chitotriose exhibited greater inhibition than expected for the mannosyl-fucosyl lectin.     

Intracellular growth and phagocytosis of Blastomyces dermatitidis by monocyte-derived macrophages from previously infected and normal subjects

Blastomyces dermatitidis evokes responses of human cellular immunity typical of other intracellular fungal pathogens. Differences in growth rates of intracellular Blastomyces yeast and the differences in amounts of yeast phagocytized by macrophages were determined for macrophages derived from peripheral blood monocytes from 11 persons with treated blastomycosis and 11 normal, healthy persons. Cellular immunity was examined by lymphocyte uptake of [3H]thymidine in response to a specific antigen of Blastomyces yeast. Yeast were more readily phagocytized by macrophages from the previously treated donors when compared with those from the normal donors; the yeast were confirmed to be intracellular by transmission electron microscopy. Likewise, a decrease in growth rates of yeast was demonstrable in cultures of macrophages from previously treated donors as compared with normal donors. This greater efficiency of phagocytosis and growth inhibition of B. dermatitidis reflects another mechanism of human cellular immunity to this fungal infection.     

Peritonitis caused by Blastomyces dermatitidis in a kidney transplant recipient: case report and literature review

Blastomyces dermatitidis is a dimorphic fungus endemic to the midwestern, south‐central, and southeastern United States known to cause disseminated infection in immunocompromised individuals. We report a case of B. dermatitidis peritonitis in a renal allograft recipient with new‐onset ascites and cytomegalovirus encephalitis. Peritoneal blastomycosis is a rare clinical entity and, to our knowledge, this patient represents the first known case of peritoneal blastomycosis in a solid organ transplant recipient. We review the clinical characteristics of B. dermatitidis peritonitis as well as the literature on fungal peritonitis with emphasis on dimorphic fungal pathogens. Clinical features suggestive of fungal peritonitis include new‐onset ascites, abdominal pain, and fevers, especially with antecedent or concomitant pneumonia. A high index of clinical suspicion, along with the use of culture and non‐culture diagnostics, is needed for early diagnosis and prompt initiation of therapy.     

Macrophage- and oxidant-mediated inhibition of the ability of live Blastomyces dermatitidis conidia to transform to the pathogenic yeast phase: implications for the pathogenesis of dimorphic fungal infections

Conidia, produced by the mycelial phase of dimorphic fungi, are thought to represent the infectious form of the organism but must complete a transition to the tissue-invasive, yeast-like phase for infection to ensue. Preventing such transition should effectively eliminate pathogenicity. Using Blastomyces dermatitidis as a target, murine bronchoalveolar macrophages preferentially blocked phase transition after 4 h of incubation with conidia, relatively sparing the ability of conidia to produce hyphae. H2O2, in relatively high concentrations, demonstrated the same activity. The effects of H2O2 seem irreversible, since H2O2-treated conidia that germinated at 48 h at 25 degrees C were still unable to produce yeasts over the next 5 days when incubated at 37 degrees C. Catalase could not reverse the macrophage-induced inhibition of phase transition, suggesting that nonoxidative defense mechanisms may be operative in vivo. Since conidia do not form mycelia at temperatures found in mammalian hosts, these effects may represent a novel host defense mechanism against dimorphic fungal pathogens.     

Splenic abscess caused by Blastomyces dermatitidis in association with peritoneal involvement: case report and review.

We report a rare case of a patient with blastomycosis who presented with splenic abscess and peritoneal involvement. This case is unique in that no historical or radiographic evidence of antecedent pulmonary infection was apparent and therapy with orally administered ketoconazole was effective. We reviewed the English-language literature on blastomycotic splenic abscess and compared findings from other cases with findings from the current case.     

Interstitial pulmonary fibrosis induced in hamsters by intratracheally administered chrysotile asbestos. Histology, lung mechanics, and inflammatory events

The development of interstitial pulmonary fibrosis (IPF) is associated with persistent cellular infiltration and progressive connective tissue accumulation in the alveolar walls. To develop and characterize an animal model of IPF in which pulmonary fibrosis evolves slowly, as well as to develop an inexpensive, easily produced, model of asbestosis, Syrian golden hamsters received single intratracheal injections of either UICC chrysotile asbestos or saline. Animals were then examined at time points up to 180 days for pulmonary histologic and physiologic changes, cytologic characteristics of cells recovered by bronchoalveolar lavage, and spontaneous release of neutrophil chemoattractant activity by alveolar macrophages. Within days after asbestos treatment, hamsters developed a patchy bronchopneumonia centered around terminal airways, which progressed peripherally with time to involve the alveolar walls with persistent inflammation and the gradual development of interstitial and peribronchiolar fibrosis. These histologic changes were accompanied by physiologic findings of air-flow obstruction with air trapping. Bronchoalveolar lavage revealed a persistent neutrophilia that began within 24 h of asbestos treatment; this was associated with the spontaneous release of neutrophil chemotactic activity by cultured alveolar macrophages. In this animal model, pulmonary inflammation and fibrosis can be predictably produced by a single intratracheal instillation of chrysotile asbestos. It represents a useful tool for studying both asbestosis and pulmonary fibrosis in general.     

慢性阻塞性肺疾病合并肺血栓栓塞症

肺血栓栓塞症(pulmonary thromboembolism,PTE)是较常见的呼吸系统疾病,未经治疗时其病死率高达30%,得到及时诊断和正确治疗时则可降至8%[1]。呼吸困难是PTE的最常见临床表现,也是慢性阻塞性肺疾病(chronicobstructive pulmonary disease,COPD)的标志性症状,当COPD合并PTE时,临     

Chronic hepatitis induced by alcohol

Fifteen heavy drinkers with the histological features of chronic hepatitis were studied. Chronic hepatitis observed in heavy drinkers can be divided into two categories. One is caused by alcohol, and the other is not etiologically related to alcohol. Chronic hepatitis caused by alcohol showed a definite improvement of clinical features following abstinence, as well as significantly high serum GOT/GPT ratios and high glutamate dehydrogenase activities on admission. These clinical features are distinctly different from chronic hepatitis without etiological relation to alcohol and resemble the other types of alcoholic liver injury. The leukocyte migration inhibition test by ethanol was more frequently positive in chronic hepatitis induced by alcohol than in the other types of alcoholic liver injury except for alcoholic hepatitis. Histological characteristics of the liver in chronic hepatitis induced by alcohol included the coexistence of features of both chronic hepatitis and alcoholic fibrosis. Three of four cases of chronic hepatitis induced by alcohol developed cirrhosis during the follow-up period. These results suggest that chronic hepatitis induced by alcohol is a type of alcoholic liver disease with an immunopathological etiology. It is a step toward the development of liver cirrhosis.     

Chronic myeloproliferative disease induced by site-specific integration of Abelson murine leukemia virus-infected hemopoietic stem cells.

We recently showed that hemopoietic stem cells expressing the v-abl oncogene can cause leukemia when injected into lethally irradiated recipient mice. Progenitor cells expressing v-abl did not significantly contribute to disease development, and the leukemia was monoclonal in origin. By serially transplanting v-abl-transduced hemopoietic stem cells into normal, nonirradiated syngeneic recipients, we showed that multiple stem-cell clones do exist in some recipients. These cells fluctuated as normal stem cells do and could home to normal bone marrow. Based on the time course of disease, the recipients developed either an acute or a chronic phase of disorder. All recipients with the acute disease had stem-cell clones with random Abelson murine leukemia virus integration sites. All recipients with the chronic disorder had a specific Abelson murine leukemia virus integration site. We believe this abl-specific integration site, termed ASI, is important in abl-mediated stem-cell leukemogenesis.     

鼠巨细胞病毒感染BALB/c小鼠心肌炎模型的建立

目的:建立鼠巨细胞病毒(MCMV)感染心肌炎动物模型。方法:用巨细胞病毒经腹腔注射感染BALB/c小鼠。结果:MCMV感染小鼠心肌炎发病率为69.4%,死亡高峰在感染后7～14d,死亡率为11.11%;44.5%的感染鼠出现心外膜炎。MCMV感染的第7天,心肌细胞出现肿胀、变性,血管周围有大量炎症细胞灶性浸润;第14天,可见单个心肌细胞核固缩、溶解,心肌细胞小灶性坏死、崩解,周围见单核细胞、淋巴细胞浸润;病变于感染后7～14d达高峰,第14天后开始减轻。MCMV感染小鼠全部心肌病变积分均≤2分,属轻度心肌炎改变;心电图的改变率达50%。结论:该心肌炎动物模型为探讨病毒性心肌炎的发病机制、转归及抗病毒药物的筛选提供了有力的工具。     

Early-stage developmental abnormalities induced by murine cytomegalovirus

The onset of the effects of murine cytomegalovirus (MCMV) infection on an early stage of embryonic development (nine days) in a mouse model was studied with the aid of scanning electron microscopy. MCMV was injected into the endometrial lumina of pregnant mice at the time of implantation. The mice were later killed, and sites of embryonic implantation were examined. Compared with uninfected mice and mice inoculated with heat-inactivated virus, litter sizes were reduced, and the incidence of abnormal fetuses was significantly increased among MCMV-infected animals. Scanning electron microscopy also revealed maldeveloped cranial regions characterized by an unclosed neural tube and severely underdeveloped head. Ectodermal abnormalities, including poxlike formations and ballooning cells, were observed in several embryos. Thus, early cytomegalovirus infection may not only result in fetal loss, but may also interfere with the process of morphogenesis.