A second cytotoxic proteolytic peptide derived from amyloid beta-protein precursor

The amyloid beta-protein precursor gives rise to the amyloid beta-protein, the principal constituent of senile plaques and a cytotoxic fragment involved in the pathogenesis of Alzheimer disease. Here we show that amyloid beta-protein precursor was proteolytically cleaved by caspases in the C terminus to generate a second unrelated peptide, called C31. The resultant C31 peptide was a potent inducer of apoptosis. Both caspase-cleaved amyloid beta-protein precursor and activated caspase-9 were present in brains of Alzheimer disease patients but not in control brains. These findings indicate the possibility that caspase cleavage of amyloid beta-protein precursor with the generation of C31 may be involved in the neuronal death associated with Alzheimer disease.

Invasive aspergillosis presenting as a cavernous sinus mass in immuno competent individuals; report of 3 cases

Aspergillosis of the cavernous sinus is rare, especially in immuno competent individuals. We report three such cases secondary to paranasal sinus aspergillosis, with imaging findings.

Optic nerve cysticercosis: imaging findings

We present the imaging findings of retrobulbar optic nerve cysticercosis in a 50-year-old woman with a 6-month history of vision loss. Contrast-enhanced CT revealed an approximately 7-mm ring-enhancing cyst with a mural nodule located in the anterior portion of the left optic nerve. A contrast-enhanced MR imaging study revealed a cystic lesion with peripheral enhancement of the mural nodule. Sonography showed a cystic mass with a focal area of increased echogenicity corresponding to the mural nodule.

Complementary role of two fragments of domain V of 23 S ribosomal RNA in protein folding

We have shown that the domain V of bacterial 23 S rRNA could fold denatured proteins to their active state. This segment of 23 S rRNA could further be split into two parts. One part containing mainly the central loop of domain V could bind denatured human carbonic anhydrase I stably. This association could be reversed by adding the other part of domain V. The released enzyme was directed in such a way by the central loop of domain V that it could now fold by itself to active form. This agrees with our earlier observation that proteins fold within the cell posttranslationally, a process that is completed after release of the newly synthesized polypeptide from the ribosome (Chattopadhyay, S., Pal, S., Chandra, S., Sarkar, D., and DasGupta, C. (1999) Biochim. Biophys. Acta 1429, 293-298).

Three-dimensional segmentation of luminal and adventitial borders in serial intravascular ultrasound images

Intravascular ultrasound (IVUS) provides exact anatomy of arteries, allowing accurate quantitative analysis. Automated segmentation of IVUS images is a prerequisite for routine quantitative analyses. We present a new three-dimensional (3D) segmentation technique, called active surface segmentation, which detects luminal and adventitial borders in IVUS pullback examinations of coronary arteries. The technique was validated against expert tracings by computing correlation coefficients (range 0.83-0.97) and William's index values (range 0.37-0.66). The technique was statistically accurate, robust to image artifacts, and capable of segmenting a large number of images rapidly. Active surface segmentation enabled geometrically accurate 3D reconstruction and visualization of coronary arteries and volumetric measurements.

Heme binding and polymerization by Plasmodium falciparum histidine rich protein II: influence of pH on activity and conformation

The histidine rich protein II (HRPII) from Plasmodium falciparum has been implicated as a heme polymerase which detoxifies free heme by its polymerization to inactive hemozoin. Histidine-iron center coordination is the dominant mechanism of interaction between the amino acid and heme. The protein also contains aspartate allowing for ionic/coordination interactions between the carboxylate side chain and the heme metal center. The pH profile of heme binding and polymerization shows the possibility of these two types of binding sites being differentiated by pH. Circular dichroism studies of the protein show that pH and heme binding cause a change in conformation above pH 6 implying the involvement of His-His+ transitions. Heme binding at pHs above 6 perturbs HRPII conformation, causing an increase in helicity.

Effect of endodontic smear layer and various solvents on the calcium ion diffusion through radicular dentin--an in vitro study

External root resorption and ankylosis remains the major cause of failure of replanted teeth. This study was conducted to explore the different ways to increase the pH of periradicular area in order to overcome the problem of root resorption and ankylosis. 60 freshly extracted permanent anteriors were used after removing the crown at CEJ. After biomechanical preparation Ca (OH)2 was injected and assays were done using EDTA, Citric and tannic acid Assays were repeated. Calcium diffusion and pH in the root exterior was measured using spectrophotometer. Results showed that dentin is permeable to calcium & hydroxyl ions and placement of Ca (OH)2 in the canal resulted in its increased recovery and alkaline pH periradicularly. Smear layer removal did not result in significant increase in Ca++ recovery or alkaline pH however combination of EDTA & NaOCl was found best than the other two.

Metal chelators/antioxidants: approaches to protect erythrocytic oxidative stress injury during Plasmodium berghei infection in Mastomys coucha

Desferal, N-acetyl penicillamine (metal chelators) and propylgallate, catechin, and reduced glutathione (antioxidants) suppressed the erythrocytic oxidative damage generated during Plasmodium berghei infection in Mastomys coucha. Superoxide anion and lipid peroxide levels were increased and on the contrary, superoxide dismutase activity was noticeably decreased in the infected erythrocytes. Metal chelators/antioxidant treatment to infected animals resulted in restoration of O(2)(-), LPO and SOD to near normal levels. Furthermore, treatment of the above mentioned agents displayed a controlled mortality/survival time and parasitaemia. In conclusion, metal chelators/antioxidants were found to be effective against oxidative stress injury and parasite growth resulting in prolonged survival time of the host during experimental malaria.

Solitary nodular goiter. Review of cytomorphologic features in 441 cases

OBJECTIVE

To study the cytomorphologic features of solitary nodular goiters (SNG).

STUDY DESIGN

May-Grünwald-Giemsa-stained smears in 441 SNG diagnosed by ultrasonography and fine needle aspiration (FNA) and found to have optimum cellular material at review were subjected to detailed cytologic assessment. The age of the patients ranged from 11 to 75 years, with a median of 35. Male: female ratio was 69:372. The parameters for cytologic assessment included cellularity, colloid content, acinar formation, papillary formation, intranuclear cytoplasmic inclusions, nuclear grooves, marginal vacuoles, Hürthle cells and various inflammatory cells. Histopathology reports on thyroidectomy specimens were available in 27 cases from two Delhi hospitals.

RESULTS

Hyperplastic nodules (68 cases) differed significantly from colloid goiters (269 cases) by having more cases with excessive cellularity, acinar formation and marginal vacuoles (P < .001). There was also a significant difference with respect to papillary formation and moderate-to-excessive colloid content (P < .001). As compared to hyperplastic nodules, neoplasms (60 cases) had a significantly higher number of cases with papillary formation, intranuclear inclusions and nuclear grooves but lower number of cases with marginal vacuoles (P < .01-.001). Among neoplasms, usual papillary carcinoma (19 cases) differed from follicular neoplasms (20 cases) with respect to acinar formation, papillary formation and nuclear grooves (P < .001). A significant difference was also observed with respect to colloid content and nuclear inclusions. Follicular variant of papillary carcinomas (FVPC) (10 cases) emerged as a distinct cytologic entity following review and differed from usual papillary carcinomas in having a higher number of cases with acinar formation, tubular formation and marginal vacuoles (P < .01-.001) and lower number of cases with nuclear grooves (P = .05). FVPC also differed from follicular neoplasms with respect to papillary formation, tubular formation, intranuclear inclusions and nuclear grooves (P < .01-.001). Overall cytohistologic agreement was achieved in 24 of 27 (88.9%) cases.

CONCLUSION

Detailed cytologic assessment of FNA smears-in SNG was helpful in highlighting parameters that differentiate between various types of goiters.

Magnetic resonance imaging and ultrasonography in the diagnosis of a malignant peripheral nerve sheath tumor in a dog

A 9-year-old male neutered mixed breed dog had a two-month history of progressive left thoracic limb lameness. There was electromyographic evidence of denervation potentials in all muscles of this limb. In magnetic resonance images a multilobulated, hyperintense mass was visible caudal to the middiaphysis of the left humerus on T-2 weighted images. The mass, which was isointense with surrounding tissue on T1 weighted images, extended proximally towards the brachial plexus. The mass was also visible as a fusiform structure of mixed echogenicity sonographically, although fine-needle aspiration performed at this time was nondiagnostic. A malignant peripheral nerve sheath tumor was diagnosed histopathologically.

Imaging of total calcium in urediospore germlings of Uromyces by ion microscopy

Calcium has been implicated in growth and appressorium formation of urediospore germlings of the bean rust fungus, Uromyces appendiculatus. Using ion microscopy, a mass spectrometry-based imaging technique, intracellular stores of calcium were analyzed by direct imaging of total calcium in frozen freeze-dried germlings. Calcium concentration was calculated by ratioing and spatially registering (40)Ca to (12)C signals. Intracellular distributions of total potassium, sodium, magnesium, and carbon were similarly imaged in the same germlings for a direct comparison of their localizations to total calcium. Calcium was remarkably heterogeneous with highest concentrations (2 to 10 mM) in the mid-region of the germling between the nuclei and the apex. A similar distribution of Ca(2+) (assessed using Fluo-3) was also noted sequestered in organelles in live germlings. Distributions of remaining elements (K, Na, Mg, and C) were mostly homogeneous throughout the cytoplasm and nuclei of the fungal cell. The K/Na ratio ranged from 17 to 31.

Splenic tuberculosis: an unusual sonographic presentation

Tuberculosis (TB) of the spleen is rare, especially in the immunocompetent. Recently there has been an increase in the incidence of splenic TB, primarily attributable to the raging HIV epidemic. Almost all cases of splenic TB present as multiple hypoechoic foci (< 2 cm) on ultrasonography. We present a case of a large solitary splenic tuberculoma in a middle-aged, non-immunosuppressed female, an employee at the local TB hospital. To the best of our knowledge, only two such cases have been described on ultrasound before. We suggest that, regardless of immune status, splenic TB should be considered as a diagnostic possibility when dealing with the solitary nodules of the spleen, especially when there is a history of exposure to or evidence of tuberculous foci elsewhere in the body.

Use of diffusion-weighted MRI and neurological deficit scores to demonstrate beneficial effects of isradipine in a rat model of focal ischemia

The neuroprotective effects of isradipine, a 2,4-dihydropyridine calcium channel blocker, has been well studied in the rat model of focal ischemia (induced by middle cerebral artery occlusion, MCAO). The present study was designed to evaluate whether isradipine pretreatment caused early (0-3 h after stroke) ischemic changes in diffusion- weighted magnetic resonance imaging (DWI) and if such changes were predictive of previously documented protection in brain infarction. An initial dose-response study using neurological deficit scores and estimates of protection from brain infarction (by histology) showed that isradipine reduced cortical infarctions compared to vehicle-treated animals at most doses (between 1.25 and 5 mg/kg/day s.c. for 6 days) with the best results obtained at 5 mg/kg/day, where a 78.5% reduction was observed. This dose was utilized to perform the DWI study. Early quantitative estimates of infarct size, as measured by DWI at 1, 2 and 3 h after MCAO, were similar to those obtained with late histology at 24 h. These data indicate that in pretreatment protocols, DWI can be used to quantitatively predict areas at risk of permanent damage. This work also demonstrates that neurological deficits, developing from the damaged forebrain following focal stroke, may provide an index of isradipine's neuroprotective activity.

An evaluation of plaster of Paris barriers used under various materials to repair furcation perforations (in vitro study)

The present study was undertaken to evaluate the effect of plaster of Paris barriers on the sealing ability of various materials when used to repair furcation perforations. The study was conducted on 90 human permanent molars with well developed, nonfused roots. Access openings and furcation perforations were prepared in the pulp chamber floor. The teeth were divided into one control and five experimental groups of 15 teeth each. In the experimental group, plaster of Paris barriers were created in the perforations and then sealed with silver amalgam, glass ionomer (GI), self-cured composite resin, IRM, or AH26. Access openings were filled with composite resin. The teeth were submerged in a solution of 2% methylene blue dye for 2 wk. Finally, the samples were sectioned and evaluated for linear dye leakage and analyzed statistically. Maximum dye penetration was observed in amalgam followed in a decreasing order by GI, composite, IRM, and AH26. AH26 showed the best sealing ability in the presence of plaster of Paris barriers followed by IRM, composite resin, and GI. Amalgam showed the poorest sealing ability when used to repair furcation perforations.

Virus reduction in the preparation of intravenous immune globulin: in vitro experiments

BACKGROUND

While immune globulins for intravenous administration (IGIV) have an excellent record with respect to virus safety, concern regarding these preparations has been raised by reports of transmission of hepatitis C virus (HCV) to patients treated with IGIV and the presence of genetic material for HCV in IGIV preparations.

STUDY DESIGN AND METHODS

This in vitro study evaluated the effectiveness of several manufacturing steps, including ethanol precipitation and pasteurization, in reducing HIV and model viruses including encephalomyocarditis (EMC) virus, pseudorabies virus (PRV), bovine viral diarrhea virus (BVDV), Sindbis virus, vaccinia virus, and vesicular stomatitis virus (VSV), as well as HCV RNA, in IGIV.

RESULTS

Ethanol precipitation carried out after pasteurization resulted in virus reductions (log10) of >3.97 for HIV, 1.95 for EMC virus, >5.39 for PRV, and 3.52 for BVDV. Pasteurization inactivated EMC virus by 4.52 log10 and resulted in a log10 reduction of >6.54 for HIV, >5.39 for PRV, >6.64 for BVDV, >7.78 for Sindbis virus, >5.84 for vaccinia virus, and >6.99 for VSV. All viruses except EMC virus were reduced below the limit of detection within 6 hours of the beginning of pasteurization. Cohn processing of Fraction II + III paste and the 4.5-percent alcohol precipitation step prior to pasteurization provided additional virus removal. Studies using the polymerase chain reaction technique found that HCV RNA was detectable in the starting fraction of Cohn Fraction II paste, but not in the final IGIV preparation.

CONCLUSION

These findings strongly support the viral safety of IGIV prepared by this method and show a significant added measure of virus safety associated with pasteurization of this preparation.

Protein folding in Escherichia coli: role of 23S ribosomal RNA

Post-translational control of Escherichia coli ribosome on newly synthesised polypeptide leading to its active conformation (protein folding) has been shown in the case of the enzyme beta-galactosidase. As expected, antibiotics chloramphenicol and lincomycin, which bind to 23S rRNA/50S subunit and kasugamycin and streptomycin which interact with the 30S subunit instantaneously inhibited protein synthesis when they were added to the growing cells. The increase in beta-galactosidase activity, though stopped immediately after the addition of chloramphenicol and lincomycin, went on considerably in the presence of streptomycin and kasugamycin even after the stoppage of protein synthesis.

A generic mixing system for achieving conditions suitable for single point representative effluent air sampling

The U.S. EPA has approved Alternate Reference Methodologies for sampling radionuclide aerosol particles from stacks and ducts of U.S. DOE facilities. The approach allows use of single point sampling with shrouded probes from locations where both fluid momentum and contaminant concentration are well mixed across the flow cross section. For existing stacks and ducts that do not have locations where there is adequate mixing, we have developed a generic mixing system that will generate conditions suitable for single point sampling. The coefficients of variation of the velocity, tracer gas, and 10 microm aerodynamic diameter aerosol particles profiles are all less than 10%, which are well within the EPA limit of 20%. Mixing is affected neither by size of the system nor by flow rate, provided the flow is turbulent.

Crosswire for recanalization of total occlusive coronary arteries

Coronary angioplasty of total occlusions is technically difficult and is associated with limited success rates. The procedural outcome is mainly determined by the underlying pathological process. Recanalization of total occlusions is aimed at finding the passage with least resistance, without causing dissection or perforation. Several techniques have been advocated to improve the overall success rate. Recently, a new 0.014" Nitinol wire (Crosswire, Terumo) has been introduced as a tool, to achieve higher success rates for total occlusion angioplasty. The wire consists of an extremely flexible Nitinol-core, a platinum/iridium coil at the distal tip, and a hydrophilic polymer coating. Balloon angioplasty was attempted in 30 totally occluded coronary arteries with mean age of occlusion being 5 +/- 4 months (range 2-14 months). The initial five procedures were performed following failure of the conventional angioplasty guidewires. Subsequently, Cross-wire was used electively in all the cases. The lesion was crossed successfully in 90% (27/30) cases. Dissection of the coronary artery with subintimal entry was seen in two (7%) cases, and the rest (three cases) could not be crossed. Balloon angioplasty and stenting (n = 21) were performed with good immediate angiographic results. There were no myocardial infarctions or deaths. Fourteen of 16 patients, who had completed 6 months follow-up, were asymptomatic. Angiographic evidence of in-stent restenosis was demonstrable in one case. Successful recanalization of total coronary occlusions by using Cross-wire can be expected in 83% cases, with reasonable safety.