Pulmonary cryptococcosis

Summary C. neoformans was isolated from the sputum of a patient admitted with signs and symptoms of bacterial pneumonia. This is the third reported isolation of the fungus from India. The significance of the finding is discussed.     

Pulmonary cryptococcosis: A rare but emerging disease

Pulmonary cryptococcosis occurs primarily in immunocompromised hosts as an isolated infection or as a precursor to disseminated disease. Recent studies indicate that patients with isolated pulmonary cryptococcosis may be asymptomatic or, if symptomatic, will often have very low serum cryptococcal antigen, distinguishing them from patients with disseminated disease. Amphotericin B plus flucytosine is the initial treatment for disseminated cryptococcosis or severe symptomatic pulmonary cryptococcosis, followed by fluconazole once symptoms have improved. Fluconazole is recommended for asymptomatic or mild disease. Targeted immunotherapies and vaccines are being studied and offer exciting new prevention and treatment strategies.     

Pulmonary cryptococcosis in late pregnancy and review of published literature

Naturally occurring maternal immunosuppression increases the risk of infection by a variety of pathogens during pregnancy and the postpartum period. Pulmonary cryptococcosis during pregnancy is relatively rare. Here, we report on two cases of pulmonary cryptococcosis during pregnancy and puerperium. Both cases were successfully treated using oral fluconazole after parturition to avoid fetal toxicity. For the two patients, the placentas were checked and found to be pathologically normal, and the cryptococcal serum antigen in both infants was negative. Pulmonary cryptococcosis should be considered during differential diagnosis as a possible cause of abnormal chest shadow in pregnant patients.     

Pulmonary cryptococcosis due to a capsule-deficient strain confused with metastatic lung cancer

A patient with hepatocellular cancer developed pulmonary cryptococcosis due to infection with a capsule-deficient Cryptococcus neoformans. Pulmonary lesions initially diagnosed as metastatic cancer by chest x-ray film and CT scan were subsequently found to be fungal granulomas by autopsy. Although morphologic studies of the fungi were insufficient to render a specific mycologic diagnosis because of the absence of encapsulated yeasts, fluorescent antibody studies confirmed the diagnosis of cryptococcosis. The use of various stains and electron microscopy for the pathological differential diagnosis of cryptococcosis caused by capsule-deficient yeasts is discussed. This revised version was published online in August 2006 with corrections to the Cover Date.     

Methyl jasmonate induces expression of a novel Brassica juncea chitinase with two chitin-binding domains

We have cloned a 1.3 kb Brassica juncea cDNA encoding BjCHI1, a novel acidic chitinase with two chitin-binding domains that shows 62% identity to Nicotiana tabacum Chia1 chitinase. BjCHI1 is structurally unlike Chia1 that has one chitin-binding domain, but resembles Chia5 chitinase UDA1, the precursor of Urtica dioica agglutinin; however there is only 36.9% identity between them. We propose that BjCHI1 should be classified under a new class, Chia7. The spacer and the hinge region of BjCHI1 are proline-rich, like that of Beta vulgaris Ch1, a Chia6 chitinase with half a chitin-binding domain. Northern blot analysis showed that the 1.3 kb BjCHI1 mRNA is induced by wounding and methyl jasmonate (MeJA) treatment but is unaffected by ethylene, salicylic acid (SA) or abscisic acid (ABA). This is the first report on MeJA induction of chitinase gene expression and further suggests that wound-related JA-mediated signal transduction is independent of that involving SA. Western blot analysis using polyclonal antibodies against BjCHI1 showed a cross-reacting band with an apparent molecular mass of 37 kDa in wounded tissues of B. juncea, revealing that, unlike UDA1, BjCHI1 is not cleaved post-translationally at the hinge. Expression of recombinant BjCHI1 in Escherichia coli BL21(DE3) inhibited its growth while crude extracts from E. coli JM109 expressing recombinant BjCHI1 showed chitinase activity. Results from polymerase chain reaction (PCR) suggest that genes encoding chitinases with single or double chitin-binding domains exist in B. juncea.     

Chronic hyperhomocysteinemia induces oxidative damage in the rat lung

Tissue accumulation of homocysteine occurs in classical homocystinuria, a metabolic disease characterized biochemically by cystathionine β-synthase deficiency. Vascular manifestations such as myocardial infarction, cerebral thrombosis, hepatic steatosis, and pulmonary embolism are common in this disease and poorly understood. In this study, we investigated the effect of chronic hyperhomocysteinemia on some parameters of oxidative stress (thiobarbituric acid-reactive substances, protein carbonyl content, 2',7'-dichlorofluorescein fluorescence assay, and total radical-trapping antioxidant potent) and activities of antioxidant enzymes (superoxide dismutase, catalase, and glutathione peroxidase) in the rat lung. Reduced glutathione content and glucose 6-phosphate dehydrogenase activity, as well as nitrite levels, were also evaluated. Wistar rats received daily subcutaneous injections of Hcy (0.3-0.6 μmol/g body weight) from the 6th to the 28th days-of-age and the control group received saline. One and 12 h after the last injection, rats were killed and the lungs collected. Hyperhomocysteinemia increased lipid peroxidation and oxidative damage to protein, and disrupted antioxidant defenses (enzymatic and non-enzymatic) in the lung of rats, characterizing a reliable oxidative stress. In contrast, this amino acid did not alter nitrite levels. Our findings showed a consistent profile of oxidative stress in the lung of rats, elicited by homocysteine, which could explain, at least in part, the mechanisms involved in the lung damage that is present in some homocystinuric patients.     

Pulmonary ischemia induces lung remodeling and angiogenesis.

Cellular remodeling during angiogenesis in the lung is poorly described. Furthermore, it is the systemic vasculature of the lung and surrounding the lung that is proangiogenic when the pulmonary circulation becomes impaired. In a mouse model of chronic pulmonary thromboembolism, after left pulmonary artery ligation (LPAL), the intercostal vasculature, in proximity to the ischemic lung, proliferates and invades the lung (12). In the present study, we performed a detailed investigation of the kinetics of remodeling using histological sections of the left lung of C57Bl/6J mice after LPAL (4 h to 20 days) or after sham surgery. New vessels were seen within the thickened visceral pleura 4 days after LPAL predominantly in the upper portion of the left lung. Connections between new vessels within the pleura and pulmonary capillaries were clearly discerned by 7 days after LPAL. The visceral pleura and the lung parenchyma showed intense tissue remodeling, as evidenced by markedly elevated levels of both proliferating cell nuclear antigen and terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling positive cells. Rapidly dividing cells were predominantly macrophages and type II pneumocytes. The increased apoptotic activity was further quantified by caspase-3 activity, which showed a sixfold increase relative to naive lungs, by 24 h after LPAL. Because sham surgeries had little effect on measured parameters, we conclude that both thoracic wound healing and pulmonary ischemia are required for systemic neovascularization.     

Renal failure induces telomere shortening in the rat heart

BackgroundRenal failure aggravates pathological cardiac remodelling induced by myocardial infarction (MI). Cardiac remodelling is associated with telomere shortening, a marker for biological ageing. We investigated whether mild and severe renal failure shorten cardiac telomeres and excessively shorten telomeres after MI. MethodsRats were subjected to sham, unilateral (UNX) or 5/6th nephrectomy (5/6NX) to induce none, mild or severe renal failure. MI was induced by left coronary artery ligation. Renal function parameters and blood pressure were measured. DNA was isolated from non-infarcted cardiac tissue. Telomere length was assessed by quantitative polymerase chain reaction (PCR). ResultsProteinuria was unchanged in UNX and MI compared with control, but strongly increased in 5/6NX, UNX+MI and 5/6NX+MI. Serum creatinine levels were increased fourfold in 5/6NX and tenfold in 5/6NX+MI. 5/6NX and groups with both renal failure and MI showed an approximate 20% reduction of telomere length, similar to the MI group. No excess telomere shortening was observed in hearts from rats with renal ablation after MI. ConclusionSevere renal failure, but not mild renal failure, leads to shortening of cardiac telomeres to a similar extent as found after MI. Renal failure did not induce excessive telomere shortening after MI. (Neth Heart J 2009;17:190–4.)     

Histamine induces ovulation in the isolated perfused rat ovary

Ovulatory effects of histamine and specific antagonists were studied in isolated perfused ovaries from immature rats treated with 10 i.u. PMSG to stimulate follicular growth and maturation. Histamine alone, like LH, induced ovulation in all ovaries tested, but the number of follicular ruptures was lower after histamine (7.0 and 2.2 ruptures, respectively, per ovary). The histamine-induced ovulations could be inhibited dose-dependently by the H1-receptor antagonist, pyrilamine, or the H2-antagonists, cimetidine and ranitidine. At the concentrations tested, these antagonists did not, when given separately, reduce the LH-induced ovulations significantly, but pyrilamine and cimetidine in combination lowered the ovulation frequency by 65%. The prostaglandin synthesis inhibitor, indomethacin, was not able to block the histamine-induced ovulations.     

Acetaminophen induces apoptosis in rat cortical neurons

Background

Acetaminophen (AAP) is widely prescribed for treatment of mild pain and fever in western countries. It is generally considered a safe drug and the most frequently reported adverse effect associated with acetaminophen is hepatotoxicity, which generally occurs after acute overdose. During AAP overdose, encephalopathy might develop and contribute to morbidity and mortality. Our hypothesis is that AAP causes direct neuronal toxicity contributing to the general AAP toxicity syndrome.

Methodology/Principal Findings

We report that AAP causes direct toxicity on rat cortical neurons both in vitro and in vivo as measured by LDH release. We have found that AAP causes concentration-dependent neuronal death in vitro at concentrations (1 and 2 mM) that are reached in human plasma during AAP overdose, and that are also reached in the cerebrospinal fluid of rats for 3 hours following i.p injection of AAP doses (250 and 500 mg/Kg) that are below those required to induce acute hepatic failure in rats. AAP also increases both neuronal cytochrome P450 isoform CYP2E1 enzymatic activity and protein levels as determined by Western blot, leading to neuronal death through mitochondrial–mediated mechanisms that involve cytochrome c release and caspase 3 activation. In addition, in vivo experiments show that i.p. AAP (250 and 500 mg/Kg) injection induces neuronal death in the rat cortex as measured by TUNEL, validating the in vitro data.

Conclusions/Significance

The data presented here establish, for the first time, a direct neurotoxic action by AAP both in vivo and in vitro in rats at doses below those required to produce hepatotoxicity and suggest that this neurotoxicity might be involved in the general toxic syndrome observed during patient APP overdose and, possibly, also when AAP doses in the upper dosing schedule are used, especially if other risk factors (moderate drinking, fasting, nutritional impairment) are present.     

Adrenaline induces mitochondrial biogenesis in rat liver

We studied the effects of adrenaline administration and depletion (induced by reserpine) on rat liver oxidative metabolism. We showed that adrenaline increases, and reserpine decreases aerobic capacity (inferred by cytochrome oxidase activity) in tissue modifying the hepatic content of mitochondrial proteins without changing mitochondrial aerobic capacity. The changes in tissue cytochrome oxidase activity, which agreed with the expression levels of factors involved in mitochondrial biogenesis, such as PGC-1, NRF-1, and NRF-2, were associated with similar changes in tissue and mitochondrial State 3 respiration. Adrenaline and reserpine induced extensive lipid and protein oxidative damage in tissue and mitochondria. The increase in H₂O₂ release by respiring mitochondria and the decrease in the activities of the antioxidant enzymes glutathione peroxidase and reductase contributed to the reserpine effect on oxidative damage. The adrenaline effect is more difficult to explain, since the hormone increased the antioxidant enzyme activities but, in respiring mitochondria, increased ROS release rate in the presence of succinate and decreased it in the presence of pyruvate/malate. These opposite changes were due to the increased content of the autoxidizable electron carrier located at complex III and decreased content of that located at complex I. Our data suggest that adrenaline can be involved in the mitochondrial population adaptation which verify in conditions in which an increased body energy expenditure verify such as cold exposure.     

Streptozotocin induces lipolysis in rat adipocytes in vitro

Streptozotocin (STZ) is used to induce experimental diabetes in animals and is also applied for the treatment of patients with insulinoma. The aim of the present work was to investigate the direct effect of STZ on lipolysis in isolated rat adipocytes. After the isolation, the cells were incubated in a Krebs-Ringer buffer of pH 7.4, at the temperature 37 degrees C for 90 min with different concentrations of STZ: 0.5, 1 or 2 mmol/l. STZ caused a significant rise in basal values (99%, 199%, and 377%, respectively) and epinephrine-stimulated (1 micromol/l) lipolysis (15%, 24% and 46%, respectively). Augmentation of basal lipolysis by STZ was neither restricted by insulin (1 nmol/l) nor by H-89 (an inhibitor of protein kinase A, 50 micromol/l). These results indicate the stimulatory influence of STZ on the action of hormone-sensitive lipase in isolated cells of white adipose tissue. The obtained outcomes suggest that in studies employing STZ, it is necessary to consider its direct effect upon lipolysis in adipocytes.     

Estrogen induces insulin-like growth factor-I expression in the rat uterus

The inability to convincingly demonstrate a mitogenic effect of estrogen on isolated uterine cells in culture suggests that autocrine or paracrine growth factors may be important in the estrogen-induced uterine proliferative response. Here we report that uterine expression of insulin-like growth factor-I (IGF-I), an important mediator of GH action, is increased after 17 beta-estradiol (5 micrograms/100 g bw, ip) administration to ovariectomized prepubertal rats. An increase in uterine IGF-I mRNA abundance, approximately 14-fold above untreated controls, was apparent 6 h after estrogen administration and the level achieved exceeded that seen in the uterus from intact mature rats during diestrus. In contrast to the increase in IGF-I expression in the uterus, no significant change in serum IGF-I concentration or hepatic or renal IGF-I mRNA abundance was demonstrable after 17 beta-estradiol injection of ovariectomized prepubertal rats. The increase in uterine IGF-I expression, was similar in both pituitary-intact and hypophysectomized, ovariectomized rats. We believe this is the first report of induction of IGF-I expression by estrogen in vivo. As such, the finding expands the role and significance of IGF-I as a mediator of growth beyond that related to GH.