A description of Lecithocladium invasor n.sp. (Digenea: Hemiuridae) and the pathology associated with two species of Hemiuridae in acanthurid fish.

Lecithocladium invasor n.sp. is described from the oesophagus of Naso annulatus, N. tuberosus and N. vlamingii on the Great Barrier Reef, Australia. The worms penetrate the oesophageal mucosa and induce chronic transmural nodular granulomas, which expand the full thickness of the oesophageal wall and protrude both into the oesophageal lumen and from the serosal surface. We observed two major types of lesions: large ulcerated, active granulomas, consisting of a central cavity containing a single or multiple live worms; and many smaller chronic fibrous submucosal nodules. Small, identifiable but attenuated, worms and degenerate worm fragments were identified within some chronic nodules. Co-infection of the posterior oesophagus of the same Naso species with Lecithocladium chingi was common. L. chingi is redescribed from N. annulatus, N. brevirostris, N. tuberosus and N. vlamingii. Unlike L. invasor n.sp., L. chingi was not associated with significant lesions. The different pathenogenicity of the two species in acanthurid fish is discussed.

Alternative splicing of amino-terminal Tau mRNA in rat spinal cord during development and following axonal injury.

Tau is a family of microtubule-associated phosphoproteins in which isoform variation is produced by alternative splicing of a single gene and posttranslational modifications. Tau isoforms that include exon 10 are overexpressed in frontotemporal dementia and progressive supranuclear palsy. Therefore, we examined the expression of tau mRNA splice variants during axonal regeneration and abortive regeneration. Previous work in our laboratory demonstrated that expression of exon 10 tau isoforms during regeneration and abortive regeneration was altered and partially recapitulated the developmental patterns of tau isoform expression. Using RT-PCR, we examined the alternative splicing of exons 2 and 3 in tau during early postnatal development and regeneration in the rat spinal cord. The levels of tau lacking exons 2 and 3 were high on the day of birth and rapidly declined. Conversely, tau isoforms containing exon 2 or exons 2 and 3 first appeared at low levels and steadily increased. During axonal regeneration, the levels of all three tau mRNA isoforms were significantly lower 7 days after injury. In a model of abortive regeneration, all of the tau isoforms were elevated 14 and 42 days postinjury. The relative levels of exon 2 and 3 tau splice variants were not altered during regeneration or abortive regeneration as occurred during development. These results suggest that tau isoform expression following neuronal injury does not recapitulate the developmental pattern and is not independently regulated as in development. Our previous results together with these data suggest that alterations in tau mRNA isoform expression that occur in neurodegeneration are not secondary to axonal injury but may be a more primary event underlying cytoskeletal derangement.

Spatiotemporal selectivity of response to Notch1 signals in mammalian forebrain precursors.

The olfactory bulb, neocortex and archicortex arise from a common pool of progenitors in the dorsal telencephalon. We studied the consequences of supplying excess Notch1 signal in vivo on the cellular and regional destinies of telencephalic precursors using bicistronic replication defective retroviruses. After ventricular injections mid-neurogenesis (E14.5), activated Notch1 retrovirus markedly inhibited the generation of neurons from telencephalic precursors, delayed the emergence of cells from the subventricular zone (SVZ), and produced an augmentation of glial progeny in the neo- and archicortex. However, activated Notch1 had a distinct effect on the progenitors of the olfactory bulb, markedly reducing the numbers of cells of any type that migrated there. To elucidate the mechanism of the cell fate changes elicited by Notch1 signals in the cortical regions, short- and long-term cultures of E14.5 telencephalic progenitors were examined. These studies reveal that activated Notch1 elicits a cessation of proliferation that coincides with an inhibition of the generation of neurons. Later, during gliogenesis, activated Notch1 triggers a rapid cellular proliferation with a significant increase in the generation of cells expressing GFAP. To examine the generation of cells destined for the olfactory bulb, we used stereotaxic injections into the early postnatal anterior subventricular zone (SVZa). We observed that precursors of the olfactory bulb responded to Notch signals by remaining quiescent and failing to give rise to differentiated progeny of any type, unlike cortical precursor cells, which generated glia instead of neurons. These data show that forebrain precursors vary in their response to Notch signals according to spatial and temporal cues, and that Notch signals influence the composition of forebrain regions by modulating the rate of proliferation of neural precursor cells.

A new macradeninine, Zebrasomatrema pichelinae n. g., n. sp. (Digenea: Lecithasteridae), from tangs (Perciformes: Acanthuridae) off the southern Great Barrier Reef, Queensland, Australia.

A new genus, Zebrasomatrema, with the type-species Z. pichelinae n. sp., is described from Zebrasoma veliferum at Heron and Lizard Islands, Queensland, Australia, and Z. scopas, Acanthurus lineatus and A. triostegus at Heron Island. The new genus shares with Acanthurotrema an anterior flange, 14 subglobular vitelline lobes, a divided seminal vesicle and a long aglandular duct joining the seminal vesicle and the short pars prostatica, but differs in its quadripartite seminal vesicle, single vitelline field, lack of a sinus-sac and excretory arms which unite in the forebody. This report constitutes the first record of a macradeninine lecithasterid in Australian waters. A key to the Macradenininae is presented.

Amyloid-beta injection in rat amygdala alters tau protein but not mRNA expression.

Previously we demonstrated local and distant changes in tau protein immunoreactivity reminiscent of those seen in Alzheimer's disease (AD) following a unilateral injection of amyloid-beta (Abeta)(25-35) into the rat amygdala. To explore the relevance of these findings to AD, we compared the effects of Abeta(1-42) to those of Abeta(25-35). Injections of both Abeta(1-42) and Abeta(25-35) into rat amygdala resulted in increased tau-2 immunolabeling in neurons. To determine whether these alterations were due to changes in the expression of tau, we measured tau protein expression by Western blotting and tau mRNA isoform expression by the reverse transcription-polymerase chain reaction in the amygdala, hippocampus, and cerebellum following a unilateral injection of Abeta(25-35) or vehicle into the amygdala. The levels of tau proteins were increased bilaterally in the amygdala of Abeta(25-35)- compared to vehicle-treated animals 8 and 16 days following treatment. The molecular weights of tau proteins were decreased in the Abeta(25-35)-treated (59-69 kDa) compared to the vehicle-treated (67-72 kDa) animals 8 days following treatment. There were no changes in tau mRNA expression in any brain region examined. In this model, just as in AD, there is an increase in tau protein levels without a change in tau mRNA expression, suggesting that Abeta peptides may influence tau protein stability in both the rat and the human brain.

Tetraphyllidean metacestodes of teleosts of the Great Barrier Reef, and the use of in vitro cultivation to identify them.

The tetraphyllidean metacestode diversity of 310 teleost fishes, including 87 species from 31 families, was examined from Heron Island, The Great Barrier Reef, Australia. Eleven metacestode 'types' were identified with the use of light microscopy. Host-specificity varied greatly among metacestode types. Incorporation of in vitro cultivation allowed generic identification for some types. Types 1 and 2 belong to Uncibilocularis Southwell, 1925, and have triloculate bothridia and one pair of forked hooks with unequal prongs; Type 3 has quadriloculate bothridia. Hook development was insufficient to determine in which genus, Acanthobothrium van Beneden, 1849 or Calliobothrium van Beneden, 1850, this type may belong. Type 4 has unilocular bothridia with simple edges and belongs to Anthobothrium van Beneden, 1850. Type 5 has multiloculated bothridia which are invaginated within pouches. This type belongs to the Rhinebothriinae although its generic identity cannot be determined. The bothridia of Type 5 everted within 24 hours of in vitro cultivation and revealed the presence of two forms, one having 48 loculi per bothridium, the other 72 per bothridium. In vitro studies provide additional support for existing theories of onchobothriid scolex development.

Autonomous and non-autonomous regulation of mammalian neurite development by Notch1 and Delta1.

BACKGROUND: On the basis of experiments suggesting that Notch and Delta have a role in axonal development in Drosophila neurons, we studied the ability of components of the Notch signaling pathway to modulate neurite formation in mammalian neuroblastoma cells in vitro. RESULTS: We observed that N2a neuroblastoma cells expressing an activated form of Notch, Notch1(IC), produced shorter neurites compared with controls, whereas N2a cell lines expressing a dominant-negative Notch1 or a dominant-negative Delta1 construct extended longer neurites with a greater number of primary neurites. We then compared the effects on neurites of contacting Delta1 on another cell and of overexpression of Delta1 in the neurite-extending cell itself. We found that N2a cells co-cultured with Delta1-expressing quail cells produced fewer and shorter neuritic processes. On the other hand, high levels of Delta1 expressed in the N2a cells themselves stimulated neurite extension, increased numbers of primary neurites and induced expression of Jagged1 and Notch1. CONCLUSIONS: These studies show that Notch signals can antagonize neurite outgrowth and that repressing endogenous Notch signals enhances neurite outgrowth in neuroblastoma cells. Notch signals therefore act as regulators of neuritic extension in neuroblastoma cells. The response of neuritic processes to Delta1 expressed in the neurite was opposite to that to Delta1 contacted on another cell, however. These results suggest a model in which developing neurons determine their extent of process outgrowth on the basis of the opposing influences on Notch signals of ligands contacted on another cell and ligands expressed in the same cell.

Lung deposition and clearance of inhaled (99m)Tc-heparin in healthy volunteers.

The purpose of this study was to quantify the lower respiratory tract (LRT) dose delivered by a single nebulization of (99m)technetium-labeled sodium heparin as well as its airway distribution, and kinetics of aerosol clearance, since inhaled heparin may be useful in the treatment of asthma. Fifteen healthy subjects (5 male, 10 female) inhaled heparin from a jet nebulizer loaded with 90,000 IU of (99m)Tc-heparin, driving flow rate 10 L/min. Lung scintigrams and blood samples were taken immediately and at several time points up to 24 h after inhalation. 15 +/- 3% (mean +/- SD) (mean 13,300 IU) of the heparin nebulizer charge reached the mouth, and 8 +/- 2% (mean 7,000 IU) was found in the LRT. Jet nebulizer residual was 48 +/- 6% (mean 43,000 IU), 32 +/- 4% (mean 29,000) was found on exhalation filters, and 5 +/- 2% in the tubing. (99m)Tc-heparin was distributed uniformly in the lungs, and clearance was biphasic. 39 +/- 8% of the LRT dose of (99m)Tc-heparin remained in the lungs 24 h after inhalation. 10.00 +/- 3.40% (687 +/- 310 IU) of the LRT dose or 0.76 +/- 0.35% of the nebulizer charge was found in the blood. Peak concentration in the blood was found 61 +/- 25 min after conclusion of inhalation, which took 15 min. We conclude that a small but significant fraction of nebulized heparin reaches the LRT. The inhaled heparin distributes uniformly in the lungs from which it clears slowly, making it suitable for local administration without induction of measurable changes in coagulation assays. Administration of the present single dose of heparin thus appears to be safe.

Overexpression of four-repeat tau mRNA isoforms in progressive supranuclear palsy but not in Alzheimer's disease.

Perturbations in the microtubule-associated protein tau occur in several human neurodegenerative diseases. In Alzheimer's disease and progressive supranuclear palsy (PSP), tau proteins assemble into straight and paired helical filaments that form intraneuronal deposits of neurofibrillary tangles (NFTs). The mechanisms underlying the aberrant assembly of tau into NFTs is unknown. To determine whether alterations in the expression of the carboxyl-terminal variants of tau contribute to NFT formation, we analyzed tau mRNA isoform expression in select regions of control, Alzheimer's disease, and PSP brains. In Alzheimer's disease, there were no alterations in tau mRNA isoform expression. However, in PSP, the levels of tau mRNA isoforms containing four microtubule binding domains were increased in the brainstem but not the frontal cortex or cerebellum. The brainstem in PSP has extensive NFT pathology, whereas the frontal cortex and cerebellum are relatively spared, suggesting that alterations in tau mRNA isoform expression occur in NFT-vulnerable regions in this disease. An increase in the four-repeat tau mRNA may lead to an increase in four-repeat tau protein isoforms and may contribute to the formation of NFTs in PSP. A similar increase in four-repeat tau mRNA has been reported for mutations associated with frontotemporal dementia and parkinsonism linked to chromosome 17.

Clickhaler (a novel dry powder inhaler) provides similar bronchodilation to pressurized metered-dose inhaler, even at low flow rates.

STUDY OBJECTIVE: Comparison of the bronchodilator response to an albuterol novel dry powder inhaler (DPI) (Clickhaler [CH]; ML Laboratories PLC; St. Albans, UK) activated at various inspiratory flow rates and to an albuterol pressurized metered-dose inhaler (pMDI) by patients with moderate to moderately severe stable asthma. DESIGN: Randomized, double-blind, placebo-controlled comparison of the bronchodilator response to albuterol DPI (200 microg) at inspiratory flow rates of approximately 15, 30, and 60 L/min in patients with stable asthma with demonstrated reversibility to albuterol. Active (albuterol via pMDI inhaled at 30 L/min) and placebo controls were included. SETTING: Single center study at the chest/allergy unit of a teaching hospital in Canada. PATIENTS: Sixteen patients with moderate to moderately severe stable asthma. MEASUREMENTS AND RESULTS: Efficacy end points were FEV1, FVC, FEV1/FVC, maximum expiratory flow, and forced expiratory flow between 25% and 75% of vital capacity. Safety end points included heart rate, BP, and tremor. There was no significant difference between the bronchodilator response to albuterol via the CH at 15, 30, and 60 L/min inspiratory flow rate and, at all flow rates, no significant difference was found comparing albuterol CH with the pMDI. All of the techniques for delivering albuterol provided significantly better bronchodilatation than placebo. Adverse events were minimal and did not differ between CH and pMDI or between the various flow rates inhaled through the CH. CONCLUSION: A novel passive albuterol DPI (CH) provides a similar bronchodilator response at 15, 30, and 60 L/min inspiratory flow rates compared with a pMDI used optimally.

Tau mRNA isoforms following sciatic nerve axotomy with and without regeneration.

The microtubule-associated protein tau promotes the polymerization and stabilization of microtubules in normal neurons and is the main component of paired helical filaments, one of the pathological structures characteristic of Alzheimer's disease (AD). In adult neurons alternative splicing generates tau isoforms with 4 microtubule binding domains (4R tau) while tau in developing neurons contains only 3 such domains (3R tau). The extra microtubule binding domain confers adult tau with an increased ability to interact with and stabilize microtubules. We hypothesized that tau gene expression would revert to the developmental pattern following nerve injury. The sciatic nerve of adult rats was unilaterally crushed or transected and tau mRNA isoform expression in the spinal cord was examined by reverse transcriptase-polymerase chain reaction. At 2 and 3 days post-crush, both the 3R and 4R tau mRNA isoform levels on the injured side had decreased compared to the contralateral side. However, the ratio of 4R to 3R tau mRNA was not significantly different between the two sides at any post-crush time point examined. Following nerve transection, a significant increase in the 3R tau mRNA isoform on the transected compared to the contralateral side occurred at 14 days; the ratio of 4R to 3R tau mRNA was significantly decreased on the transected compared to the contralateral side at 7, 14 and 42 days. These results suggest that a recapitulation of the developmental pattern of 3R tau gene expression occurs following nerve transection but not nerve crush. Our results combined with the recent findings that the 3R tau protein isoform preferentially forms paired helical filament-like structures in vitro suggests that an increased expression of the 3R tau mRNA isoform may also occur in AD.

Tau in aluminum-induced neurofibrillary tangles.

Aluminum is a neurotoxin and in susceptible species induces a neurofibrillary pathology characterized by argentophilic masses in neuronal perikarya and in axonal spheroids. These inclusions are known to contain neurofilament proteins. Using immunocytochemistry and immunoblotting, we demonstrate that tau is a component of these aluminum-induced neurofibrillary tangles (Al-NFTs) in rabbits. Double-label immunocytochemistry experiments reveal co-localization of phosphorylated neurofilaments (using SMI31) and tau (using tau-1, tau-5, AT8, and PHF-1) in the perikaryal Al-NFTs. Non-phosphorylated tau (detected using tau-1) occupies a smaller area of the Al-NFT than the total pool of tau proteins (detected using tau-5). The area of total tau and non-phosphorylated tau immunolabeling in the Al-NFT increases as the size of the Al-NFT (i.e., the proportion of cell area occupied by the Al-NFT) increases. The proportion of cell area (outside of the Al-NFT) occupied by tau (as indicated by tau-5) decreases as the area of tau in the Al-NFT increases and as the size of the Al-NFT in the cell increases. Immunoblotting experiments demonstrate 1) the specificity of the tau antibody labeling and verify a lack of cross-reactivity of the tau-5 antibody to neurofilament proteins in rabbit tissue; and 2) no alterations in the levels of tau resulting from aluminum-treatment. These data suggest that as the size of the Al-NFT in a cell increases there is less tau in the neuronal perikarya. Therefore, there may be less tau in the perikarya available to perform normal functions such as microtubule polymerization and stabilization. Tau and neurofilament proteins are perturbed in a number of neurodegenerative disorders such as Alzheimer's disease, diffuse Lewy body disease, and Parkinson's disease. Aluminum-induced neurofibrillary pathology may provide a model to study perturbation in tau and neurofilaments, their phosphorylation and deposition into pathological inclusions.

Neuronal gene expression in aluminum-induced neurofibrillary pathology: an in situ hybridization study.

Alterations in cytoskeletal proteins such as the perikaryal accumulation of neurofilaments (NFs) occur in a number of human neurodegenerative diseases including Alzheimer's disease, Parkinson's disease, and amyotrophic lateral sclerosis and may contribute to their debilitating effects. The administration of aluminum salts to rabbits induces the aberrant accumulation of NFs within the proximal axons and perikarya of vulnerable neurons and is one animal model which has been extensively studied in an attempt to gain insight into the mechanism(s) of NF perturbations in human disease. Previous studies using Northern blotting techniques to examine mRNA levels in the aluminum-induced neuropathy model have led to seemingly contradictory results. We have used in situ hybridization which provides the cellular resolution needed to: 1) determine whether there are generalized decreases in the levels of mRNA expression or decreases in mRNA encoding specific proteins; 2) determine whether alterations in mRNA levels occur specifically in neurons with NF accumulations; and 3) begin to resolve some of the apparent contradictions in the literature. A moderate dose of aluminum lactate administered on two consecutive days produced neurofibrillary tangles in spinal cord neurons seven days after the first dose. Polyadenylated mRNA levels were not altered in spinal cord neurons in aluminum-treated compared to saline-treated control animals or in tangle-bearing compared to non tangle-bearing neurons in aluminum-treated animals. Middle and high NF subunit (NFH) mRNA levels were not significantly different from polyadenylated mRNA levels in spinal cord neurons in aluminum-treated/control animals. NFH mRNA levels were decreased in neurons containing aluminum-induced NF accumulations. These results suggest that NFH gene expression may be down regulated by an inhibitory feedback mechanism induced by perikaryal accumulations of NFs. This inhibitory feedback regulation for NFH may have implications for neurodegenerative diseases in which NFs accumulate in neuronal perikarya.

Ultrasonographic evidence of uterine malignancy in the postmenopausal uterus.

The sonographically enlarged uterine cavity in the postmenopausal woman has been described as indicative of uterine malignancy. In this study, in 10 of 15 cases of proven uterine malignancy with prior pelvic sonographic studies there was evidence predicting the diagnosis. In 10 of 12 cases with positive sonographic findings, uterine malignancy was found at operation. This reveals a 67% rate of success as to the value of negative sonographic findings and an 83% rate of success with positive findings. Pelvic sonography is not a screening test for uterine malignancy, but if positive findings are present, surgical investigation is indicated.