Infection kinetics and developmental biology of Cryptosporidium muris (strain MCR) in Korean native kids and Corriedale lambs

A total of nine Korean native kids and two Corriedale lambs, 1-20 days old, were each inoculated per os with a single dose of 2 x 10(7) oocysts of Cryptosporidium muris (strain MCR) originated from mice to elucidate the kinetics and developmental stages of the coccidium in small ruminants. Irrespective of host's age, the prepatent period for both animals ranged from 19 to 35 days (28.1 days, on the average) and the patent period 16-85 days (47.8 days), and the total oocyst outputs showed enormous differences. Infection with greater numbers of oocyst outputs was not ordinarily established by transmission experiments. Oocysts discharged from the kids retained their infectivity by the mouse titration method. The immunogenicity of the coccidium and oocyst reproduction were proven by challenge infection and administration of prednisolone acetate, respectively. All the developmental stages of the coccidium in parasitophorous vacuoles were found by transmission electron microscopy in the pits of the gastric glands of a kid inoculated with oocysts and then necropsied on day 44 postinoculation. It indicated the full course of the host-parasite relationship in kids and lambs as well as mice.

Immunosuppressive effect of Cryptosporidium baileyi infection on vaccination against avian infectious bronchitis in chicks

Two-day-old commercial chicks were inoculated orally with 2 x 10(6) oocysts of Cryptosporidium baileyi and vaccinated with 10(3.5) EID50/head of a commercially available avian infectious bronchitis (IB) live virus vaccine at 4 and 14 days following inoculation. Chicks infected with C. baileyi were shown to have an immunosuppressive effect on IB virus. It is concluded that infection with the protozoon in early life may increase their susceptibility to IB.

Effect of erythrocytapheresis on arterial oxygen saturation and hemoglobin oxygen affinity in patients with sickle cell disease

An important purpose of blood transfusion in patients with sickle cell disease is to improve arterial oxygen saturation (SaO2) and thereby reduce red cell sickling. To investigate the degree of improvement in SaO2 by blood transfusion, we determined the hemoglobin oxygen affinity, transcutaneous oxygen saturation (Tc-SO2), and pulse rate before and after automated partial exchange transfusion (erythrocytapheresis). In 13 patients with sickle cell disease who underwent 24 erythrocytapheresis procedures, the mean oxygen tension at half saturation (P50) was significantly reduced from 30.4 +/- 2.2 to 26.0 +/- 1.6 mm Hg (P< 0.01) immediately after exchange transfusion. Mean Tc-SO2 values increased from 96.2 +/- 2.8 to 98.5 +/- 2.1% (P< 0.01). Approximately 50% of the increase in Tc-SO2 after erythrocytapheresis could be explained by the increase in hemoglobin oxygen affinity. An increase in arterial oxygen pressure (PaO2) following erythrocytapheresis, suggested by the calculated PaO2 in this study, may explain some of the increase in Tc-SO2. We conclude that improvement in Tc-SO2 in patients with sickle cell disease resulted from changes in hemoglobin oxygen affinity as well as blood oxygen pressure following erythrocytapheresis.

The potential role for CDC42 protein from rat brain cytosol in phospholipase D activation

Phospholipase D (PLD) has been extracted from rat brain membranes and chromatographically enriched 70-fold. From the rat brain cytosol, Cdc42 with a Mr of about 24,000 and ADP-ribosylation Factor (Arf) with a Mr of about 18,000 have been purified to near homogeneity. PLD was activated better by purified cytosolic Arf than by the other small G proteins tested. Cdc42 purified from rat brain cytosol showed 70% of PLD activation activity exerted by cytosolic Arf, suggesting that Cdc42 may be one of the major G proteins involved in the activation of membrane-associated PLD. While Cdc42 or RhoA exhibited synergistic activation of PLD when administered in conjunction with Arf, Cdc42 and RhoA showed an additive effect when used together. It is possible that Arf and Rho family proteins may have different interaction sites on PLD. These findings support a role for GTP-binding proteins of the Rho family as well as Arf in the activation of membrane-associated PLD and further suggest that Cdc42 may be a major G protein involved in the PLD activation in rat brain.

[Effects of 16-week dietary administration of 2-amino-3,8-dimethylimidazo[4, 5-f]quinoxaline in rats]

2-Amino-3,8-dimethylimidazo[4, 5-f]quinoxaline (MeIQx), a heterocyclic amine found in cooked meats, is carcinogenic in mice and rats at high doses. In order to examine the toxicity including preneoplastic changes at the lower doses, a total of 170 male Fischer 344 rats were administered MeIQx for 16 weeks at a dose of 100, 10, 1, 0.1, 0.01, 0.001 ppm or 0 ppm in the diet. The numbers of GST-P positive foci and BrdU-labeling indices in the liver were significantly increased by the dietary administration of 10 ppm and 1 ppm or more of MeIQx respectively, when compared with the basal diet-fed control rats. Aberrant cry p tfoci (ACF) were also significantly increased in the 100 ppm MeIQx group as compared to the control value. No histopathological changes indicating obvious toxicity of MeIQx were observed in the major organs other than the liver and large intestine. In conclusion, our results clearly indicate that MeIQx selectively targets the liver and large intestine of rats as organs for the toxicity, but dose not affect the other major organs at low doses.

Nitric oxide expression in airway epithelial cells in response to tubercle bacilli stimulation

In order to investigate the role of airway epithelial cells in pulmonary tuberculosis, inducible nitric oxide synthetase (iNOS) expression and nitric oxide (NO) production were studied in A549 cells. Peripheral blood mononuclear cells (PBMC) from normal volunteers were separated and cultured for 24 h with LPS or tubercle bacilli (H37Rv, H37Ra). Thereafter, A549 cells were stimulated for another 24 h with culture supernatant fluids of PBMC. iNOS messenger RNA (mRNA) expression was measured with Northern blot analysis and NO production was measured with the Griess reaction, which can measure nitrite concentration. iNOS mRNA expression and NO production were minimal in the control cells. iNOS mRNA expression and NO production were significantly increased with LPS (P < 0.05) or tubercle bacilli (P < 0.01) stimulation. However, there was no difference in iNOS mRNA expression and NO production between H37Rv and H37Ra stimulations. Interestingly, iNOS mRNA expression and NO production were greater in A549 cells stimulated with tubercle bacilli-conditioned media than in the cells stimulated with LPS-conditioned media. IL-1beta, tumour necrosis factor-alpha and interferon gamma concentrations were increased in culture supernatant fluids of PBMC stimulated with tubercle bacilli. These findings suggest that airway epithelial cells may play a certain role in the pathogenesis of pulmonary tuberculosis by producing NO. However, the role of airway epithelial cells, regarding the virulence of tubercle bacilli, was not clear in this study.

Immunosuppressive effect of Cryptosporidium baileyi infection on vaccination against Newcastle disease in chicks

Hemagglutination-inhibition titers (log2) to Newcastle disease (ND) virus were chronologically observed in chicks, which were orally inoculated with 5 x 10(5) oocysts of Cryptosporidium baileyi at 2 days of age and subsequently vaccinated with inactivated ND virus at 4 and 21 days postinoculation. In general, the titers were considerably lower in the infected chicks than those in the uninfected control throughout the experimental period (p < 0.01), and rapid negative seroconversions were observed in the infected chicks. The titers reached a peak on weeks 2 and 4 post-booster-vaccination in the control and infected chicks, respectively. Thus, C. baileyi infection was shown to have an immunosuppressive effect on ND vaccination when the agent was given to 2-day-old chicks. It is suggested that C. baileyi infection in chicks may increase the host susceptibility to ND virus.

Cloning and characterization of 4EHP, a novel mammalian eIF4E-related cap-binding protein

All eukaryotic mRNAs (except organellar) are capped at their 5' end. The cap structure (m7GpppN, where N is any nucleotide) is extremely important for the processing and translation of mRNA. Several cap-binding proteins that facilitate these processes have been characterized. Here we describe a novel human cytoplasmic protein that is 30% identical and 60% similar to the human translation initiation factor 4E (eIF4E). We demonstrate that this protein, named 4E Homologous Protein (4EHP), binds specifically to capped RNA in an ATP- and divalent ion-independent manner. The three-dimensional structure of 4EHP, as predicted by homology modeling, closely resembles that of eIF4E and site-directed mutagenesis analysis of 4EHP strongly suggests that it shares with eIF4E a common mechanism for cap binding. A putative function for 4EHP is discussed.

Ofuji papuloerythroderma associated with follicular mucinosis in mycosis fungoides

Ofuji papuloerythroderma is a distinctive clinical entity of unknown etiology, which may occasionally be associated with B cell and T cell lymphoma or visceral malignancy. We report a case of papuloerythroderma associated with follicular mucinosis in mycosis fungoides (MF) that raises the possibility of papuloerythroderma as a form of prelymphomatous skin eruption. This specific papuloerythroderma responded well to the Re-PUVA treatment, which is a combination of etretinate and PUVA photochemotherapy.

Effect of Cryptosporidium baileyi infection on antibody response to sRBC in chickens

Hemagglutinin (HA) titers to sRBC were chronologically observed in chickens orally inoculated at 2 days of age with 5 x 10(5) oocysts of Cryptosporidium baileyi. All the infected chickens exhibited negligible HA titers by 44 days postinoculation (PI). The titers were elevated as time progressed, and peaked on day 52 PI, declined gradually thereafter, and eventually reached to normal titers on day 92 PI. On the contrary, the titers in uninfected chickens were higher in comparison with infected chickens during the experiment. Chickens infected with the protozoa showed normal oocyst shedding profiles during this period. These data suggest that C. baileyi infection suppress development of humoral immunity to sRBC in chickens. It is possible that impairment of the bursa of Fabricius by cryptosporidiosis rendered chickens vulnerable to other pathogens.

Cerebral sparganosis with intracerebral hemorrhage: a case report

We describe the clinical case and radiologic findings in a woman with cerebral sparganosis in which intracerebral hemorrhage was the presenting feature with hemiparesis and dysarthria. CT demonstrated high-density lesions in the right frontoparietal area, suggesting a hematoma. With conservative management, hemiparesis improved and follow-up CT revealed what looked like a resolving hematoma. Two weeks later, she complained once again of aggravated left hemiparesis and facial weakness. Diagnosis of sparganosis was made on the basis of brain MRI and ELISA. Stereotactic surgery was performed, and a live larva of sparganum was successfully removed.

Phenidone blocks the increases of proenkephalin and prodynorphin gene expression induced by kainic acid in rat hippocampus: involvement of Fos-related antigene protein

To determine the possible role of cyclooxygenase/lipoxygenase pathway in the regulation of proenkephalin (proENK) and prodynorphin (proDYN) gene expression induced by kainic acid (KA) in rat hippocampus, the effects of esculetin, aspirin, or phenidone on the seizure activity, proENK and proDYN mRNA levels, and the level of fos-related antigene (Fra) protein induced by KA in rat hippocampus were studied. Esculetin (5 mg/kg), aspirin (15 mg/kg), or phenidone (50 mg/kg) was administered orally five times every 12 h before the injection of KA (10 mg/kg, i.p.). Seizure activity induced by KA was significantly attenuated by phenidone. However, neither esculetin nor aspirin affected KA-induced seizure activity. The proENK and proDYN mRNA levels were markedly increased 4 and 24 h after KA administration. The elevations of both proENK and proDYN mRNA levels induced by KA were inhibited by pre-administration with phenidone, but not with esculetin and aspirin. ProENK-like protein level increased by KA administration was also inhibited by pre-administration with phenidone, but not with esculetin and aspirin. The increases of proENK and proDYN mRNA levels induced by KA were well correlated with the increases of Fra protein level. Additionally, the induction of Fra protein was inhibited by pre-administration with phenidone, but not with esculetin and aspirin. The results suggest that blockade of both cyclooxygenase and lipoxygenase pathways appears to be responsible for increases of proENK and proDYN mRNA levels induced by KA via inhibiting the induction of Fra protein in rat hippocampus.

Blocking effect reduction of JPEG images by signal adaptive filtering

A postprocessing algorithm is proposed to reduce the blocking artifacts of Joint Photographic Experts Group (JPEG) decompressed images. The reconstructed images from JPEG compression produce noticeable image degradation near the block boundaries, in particular for highly compressed images, because each block is transformed and quantized independently. The blocking effects are classified into three types of noises in this paper: grid noise, staircase noise, and corner outlier. The proposed postprocessing algorithm, which consists of three stages, reduces these blocking artifacts efficiently. A comparison study between the proposed algorithm and other postprocessing algorithms is made by computer simulation with several JPEG images.

A model of chronic hypotony in the rabbit

BACKGROUND

Chronic hypotony is an important cause of functional failure after proliferative vitreoretinopathy (PVR) surgery even if the retina is successfully reattached. The purpose of this study was to create a relevant model of chronic hypotony in the rabbit.

METHODS

Eighteen pigmented rabbits weighing 3-4 kg were used in our experiment. We performed pars plana lensectomy on 14 eyes of 14 rabbits with a fragmatome and a vitreous cutter. At the end of surgery, we injected 0.2 ml of phosphate-buffered saline containing 1,00,000 cultured rabbit dermal fibroblasts over the epiciliary area. As a control, we performed pars plana lensectomy alone on four eyes of four rabbits. The intraocular pressure (IOP) was measured on days 7, 14, 21, 28. Two rabbits were killed on day 7 and prepared for histology. Two additional rabbits were killed on day 14, and the remaining ten rabbits were killed on day 28.

RESULTS

All 14 eyes following lensectomy and fibroblast injection had an IOP less than 5 mm Hg on each follow-up and a mean of 2.5 +/- 0.6 mm Hg (mean +/- SD) on day 28. Four control eyes with lensectomy alone had an IOP of 7.5 +/- 2.1 mm Hg on day 28 (P < 0.05). On gross examination, we identified a variety of pathologic changes, including the development of a fibrous translucent epiciliary membrane that caused distortion of ciliary processes, iridociliary adhesion and anterior displacement of the peripheral retina on day 28. Microscopic examination of eyes obtained on day 28 showed changes in the ciliary epithelium that included absence or atrophy of the non-pigmented ciliary epithelium, atrophy and cystic vacuolization of the pigmented ciliary epithelium, and interstitial edema of the ciliary body stroma.

CONCLUSION

We have created a model of chronic hypotony with epiciliary membrane using cultured fibroblasts in the rabbit. This model may be useful to help elucidate the pathophysiology of chronic hypotony and to investigate potential treatments.

Aspalatone, a new antiplatelet agent, attenuates the neurotoxicity induced by kainic acid in the rat

The antioxidant efficacy of aspalatone (APT; acetyl salicylic acid maltol ester), a new antiplatelet agent, has been characterized in vivo as well as in vitro, and several observations indicated that the antioxidant could prevent the neuroexcitation caused by oxidative stress. In this report, the effect of APT was evaluated on kainic acid (KA)-induced neurotoxicity, since the neurotoxicity induced by KA is, at least in part, mediated via the formation of free radicals. The results showed that pretreatments with APT or maltol (MAL) significantly attenuated seizure activity, oxidative stress (lipid peroxidation and protein oxidation) and the loss of hippocampal neurons induced by KA. On the other hand, the pretreatments with aspirin (ASP), ASP together with MAL or vitamin E failed to protect against the toxicity produced by KA suggesting that the mechanism of action for APT on the KA-induced neurotoxicity is different from that of ASP. These finding raise the possibility that salicylmaltol, a metabolite of APT, plays a role in preventing the neurotoxicity evoked by KA. Therefore, our results suggest that an APT-related antioxidant mechanism, which is linked to the MAL moiety, is involved in the neuroprotective effect against KA.

Mechanistic insights into chemopreventive effects of phenethyl isothiocyanate in N-nitrosobis(2-oxopropyl)amine-treated hamsters

The influence of phenethyl isothiocyanate (PEITC) on cell kinetics in the target organs of N-nitrosobis(2-oxopropyl)amine (BOP) tumorigenicity and on xenobiotic-metabolizing enzymes was investigated in hamsters. Female 5-week-old Syrian hamsters were given a single s.c. dose of 0, 20 or 50 mg/kg of BOP 2 h after receiving PEITC by gavage at a dose of 0, 100 or 250 mumol/animal (0, 16.3 or 40.8 mg/animal). Six and 22 h after the BOP administration, hamsters were killed and tissues were sampled. Proliferating cell nuclear antigen immunohistochemistry demonstrated significant reduction (P < 0.05-0.001) by PEITC of the labeling indices in the pancreatic acini and ducts, bronchioles, and renal tubules of the BOP-treated animals in a dose-dependent manner. In the lungs, the PEITC pretreatment significantly (P < 0.001) reduced the O6-methyldeoxyguanosine levels as compared to the BOP-alone value. Immunoblot analysis of liver cytochrome P450 isoenzymes showed CYP 2B1 to be mainly involved in the metabolic activation of BOP. PEITC significantly (P < 0.05) inhibited the induction of several isoenzymes, including CYP 2B1, while lowering the hepatic glutathione S-transferase activity as well as glutathione levels, regardless of BOP administration. Our results thus suggest that PEITC exerts its chemopreventive activity against BOP initiation of carcinogenesis in hamsters by decreasing cell turnover and DNA methylation in the target organs, and by influencing hepatic xenobiotic-metabolizing phase I enzymes, although the relationship, if any, of the latter with the former events remains to be investigated.

Effect of recombinant human erythropoietin on transfusion risk in coronary bypass patients

BACKGROUND

Patients having a cardiac operation frequently require allogeneic blood transfusions despite surgical blood-conservation techniques. Recombinant human erythropoietin (Epoetin alfa) may augment this conservation by stimulating erythropoiesis. The safety and efficacy of perioperative use of Epoetin alfa to reduce the need of allogeneic transfusion was studied.

METHODS

A multicenter double-blind, placebo-controlled, parallel-group study involved 182 patients having coronary artery bypass grafting and randomized to receive Epoetin alfa (300 or 150 IU/kg) or placebo subcutaneously for 5 days before, on the day of, and for 2 days after operation.

RESULTS

Perioperative Epoetin alfa resulted in greater increases in baseline to preoperative hemoglobin levels and hematocrit (300 IU/kg) and in presurgery to postsurgical day 1 reticulocyte counts versus placebo (p < or = 0.05). However, there was no significant difference in transfusion requirements. Incidences of adverse events were similar in all study groups.

CONCLUSIONS

Lower incidences of allogeneic blood exposure were observed in both Epoetin alfa-treated groups; however, the differences between all treatment groups were not significant. This was probably due to the relatively short 5-day preoperative course of Epoetin alfa therapy. There were no significant differences between the three groups relative to safety. Epoetin alfa was well tolerated in this population.

Sleep-disordered breathing and neuropsychological deficits. A population-based study

The relationship of sleep-disordered breathing (SOB) to neuropsychological deficits was investigated with cross-sectional data from the Wisconsin Sleep Cohort Study, a population-based study of the natural history of SDB. A sample of 841 employed men and women ages 30 to 60 yr was studied by overnight polysomnography to assess the frequency of apneas and hypopneas per hour of sleep (apnea-hypopnea index, AHI). Prior to overnight polysomnography, the participants were given a battery of neuropsychological tests for functionally important capacities including motor skills, attention, concentration, information processing, and memory. Principal factor analysis of all the neuro-psychological test data revealed a psychomotor efficiency and a memory factor. Multiple regression analysis showed a significant negative association between logarithmically transformed AHI (LogAHI) and psychomotor efficiency score independent of age, gender, and educational status (p = 0.017). The relationship was not explained by self-reported sleepiness. No significant relationship was seen between LogAHI and memory score. In assessing the clinical significance of mild SDB, we estimate that an AHI of 15 is equivalent to the decrement in psychomotor efficiency associated with 5 additional yr of age, or to 50% of the decrement associated with hypnosedative use.

Effects of Cryptosporidium muris (strain MCR) infection on gastric mucosal mast cells in mice

The responses of gastric mucosal mast cells (GMMCs) to infection with coccidian protozoa, Cryptosporidium muris, in mice were examined during primary and challenge infections. Each of three-week old ICR SPF mice was orally inoculated with a single dose of 2 x 10(6) oocysts of C. muris (strain MCR). After oocyst shedding ceased, the mice were orally challenged with a single dose of 2 x 10(6) oocysts of the same species. GMMCs reached a peak on days 20-30 postinoculation (PI) in number, and decreased thereafter. An increase on days 20-30 post-challenge-infection (PCI) was also observed. The mice showed, on the whole, normal profiles of oocyst shedding in droppings. The number of the cells of uninfected control mice remained constant. Judging from the above results, it is suggested that mastocytosis correlate with expulsion of C. muris in primary infection and the defense mechanism of challenge infection.

Dextromethorphan alters the reinforcing effect of cocaine in the rat

Dextromethorphan (DM) at supra-antitussive doses produces psychotomimetic effects in humans. In order to achieve a better understanding of the pharmacological mechanisms responsible for the behaviors induced by DM, we examined the effects of DM on the intravenous self-administration of cocaine in the rat. The effects of DM (40 mg/kg, p.o.) on responding for 0.5, 0.25, 0.125, 0.06 and 0.03 mg/kg/infusion of cocaine was assessed. DM decreased the rate of responding for higher doses of cocaine (0.5, 0.25 and 0.125 mg/kg/infusion), and increased the rate of responding for lower doses of cocaine (0.06 and 0.03 mg/kg/infusion), suggesting that DM shifted the dose-response curve for cocaine self-administration to the left. Therefore, our results indicate that the sensitivity to cocaine's behavioral effects appears to be enhanced by DM.