Neuromyelitis optica and multiple sclerosis: Seeing differences through optical coherence tomography.

Neuromyelitis optica (NMO) is an inflammatory autoimmune disease of the central nervous system that preferentially targets the optic nerves and spinal cord. The clinical presentation may suggest multiple sclerosis (MS), but a highly specific serum autoantibody against the astrocytic water channel aquaporin-4 present in up to 80% of NMO patients enables distinction from MS. Optic neuritis may occur in either condition resulting in neuro-anatomical retinal changes. Optical coherence tomography (OCT) has become a useful tool for analyzing retinal damage both in MS and NMO. Numerous studies showed that optic neuritis in NMO typically results in more severe retinal nerve fiber layer (RNFL) and ganglion cell layer thinning and more frequent development of microcystic macular edema than in MS. Furthermore, while patients' RNFL thinning also occurs in the absence of optic neuritis in MS, subclinical damage seems to be rare in NMO. Thus, OCT might be useful in differentiating NMO from MS and serve as an outcome parameter in clinical studies.

Efficient site-specific cleavage by RNase MRP requires interaction with two evolutionarily conserved mitochondrial RNA sequences.

RNase MRP is a site-specific endonuclease that processes primer mitochondrial RNA from the leading-strand origin of mitochondrial DNA replication. Using deletional analysis and saturation mutagenesis, we have determined the substrate requirements for cleavage by mouse mitochondrial RNase MRP. Two regions of sequence homology among vertebrate mitochondrial RNA primers, conserved sequence blocks II and III, were found to be critical for both efficient and accurate cleavage; a third region of sequence homology, conserved sequence block I, was dispensable. Analysis of insertion and deletion mutations within conserved sequence block II demonstrated that the specificity of RNase MRP accommodates the natural sequence heterogeneity of conserved sequence block II in vivo. Heterologous assays with human RNase MRP and mutated mouse mitochondrial RNA substrates indicated that sequences essential for substrate recognition are conserved between mammalian species.

Expression of a retroposon-like sequence upstream of the putative Trypanosoma brucei variant surface glycoprotein gene expression site promoter.

We have cloned the region spanning the putative promoter from two variant surface glycoprotein gene expression sites that are at each end of chromosome M4 of Trypanosoma brucei IsTat 7. Both expression sites contain a retroposon-like sequence (ESR) pseudogene whose 3' end is approximately 30 bp upstream of the putative expression site promoter. The ESRs from both expression sites share considerable sequence homology and are related to LINE-like elements, especially the T. brucei ingi retroposon. Other ESRs are located on large, but not intermediate or mini-, chromosomes in the IsTaR 1 serodeme, and the total copy number is 10 to 20, similar to that estimated for variant surface glycoprotein expression sites. No DNA rearrangements in the vicinity of the ESR and putative expression site promoter were detected following antigenic switches in the IsTaR 1 serodeme. ESR transcripts are present in bloodstream, but not procyclic, forms. Variation in transcript size and sequence between bloodstream variant antigenic types implies that only the ESR from the active expression site is transcribed. This pattern of expression reflects that of sequences downstream of the putative expression site promoter, suggesting that the region of coordinately controlled expression extends upstream of this promoter.

Neurophysiology of adult male Schistosoma mansoni.

From the studies on the neurophysiology of schistosomes it appears that in spite of the unique hexilaminar arrangement of the tegument's outer membrane, it has biophysical properties not markedly different from those of a variety of other multi-dimensional syncytia. The close electrical coupling of the muscle and tegument must be taken into account when one attempts to define sites and modes of action of drugs which affect motor activity. Agents which disrupt muscle function in the schistosome may exert their action indirectly by way of an effect on the tegumental membrane. The syncytial nature of the musculature and the possibility that longitudinal contraction waves are myogenic suggests that neurotransmitters may simply function as modulators of muscle activity as is the case for many vertebrate visceral muscles. External recordings indicate the presence of a variety of electrically active tissues within the schistosomes. There is no clear correlation of this activity with longitudinal muscle activity or with active membrane responses in this muscle. From this it would appear the bulk of this activity may have its origins in tissues other than the longitudinal muscle such as other muscle groups, nerve trunks, or the peripheral nerve net.

Oltipraz concentrations in plasma, buccal mucosa cells, and lipids: pharmacological studies.

Oltipraz is considered one of the most potent cancer chemoprevention agents, as shown in preclinical studies. Its pharmacological effects in humans have been associated with unusual toxicity affecting the fingers and toes. This study was designed to test intermittent dosing schedules using two dosage levels: 500 mg as a single weekly dose and 200 mg as a biweekly dose, each for 30 days. Fifteen men and women were studied in each dosing group. All were heavy smokers considered to be at high risk for developing lung cancer. Plasma, buccal mucosa cell, and lipoprotein concentrations were measured at different intervals corresponding to the time period when most of the adverse effects occur. No serious toxicities were observed using these doses and schedules. The plasma and buccal mucosa cell concentrations of Oltipraz showed substantial interindividual variations at each sampling. Some subjects had no detectable plasma or buccal mucosal cell Oltipraz concentrations. The distribution of Oltipraz incorporation into the lipid fractions and albumin was changed by the administration of different schedules of Oltipraz. The results of this study suggest that the intermittent dosing is well tolerated and does not result in steady state in plasma or buccal mucosa cells. The variation and lack of detectable Oltipraz concentration in plasma, buccal mucosa cells, and lipids may affect both the toxicity and the pharmacological effects when these doses and schedules are used.

Neuro-ophthalmologic manifestations of a paraneoplastic syndrome and testicular carcinoma.

The authors report two patients with testicular cancer who exhibited supranuclear gaze disorders as a manifestation of a paraneoplastic brainstem encephalomyelitis. In the first patient, neuro-ophthalmic dysfunction was accompanied by a prominent limbic encephalitis whereas in the second patient, an unusual, mixed pendular and jerk nystagmus was manifested. Neuroimaging revealed an enhancing hypothalamic mass in the first patient and was negative in the second. Blood from both patients contained an antibody previously reported in a patient with limbic encephalitis and testicular cancer.

The schistosomicidal compound Ro 15-5458 causes a reduction in the RNA content of Schistosoma mansoni.

The effect of Ro 15-5458 (10-2-(diethylamino)ethyl-9-acridanone(2-thiazolin- 2-yl)hydrazone) on the steady-state RNA levels of Schistosoma mansoni was studied after dosing the host with 15 mg kg-1 and retrieving parasites. Total RNA content of parasites recovered from the host 12, 72 and 96 h after dosing was reduced by 14, 30 and 41%, respectively. Quantitative filter hybridization of blots of RNA extracted from treated and control parasites with specific probes indicated a decline in actin and superoxide dismutase mRNA as well as rRNA of treated parasites. The decline was observed 12 h after dosing, 48 h before parasites showed drug-induced changes in other vital biological processes. A prominent drug-induced reduction was seen on the 1.9 kb actin mRNA compared to the 1.4 kb. The same dose of the drug did not alter the actin mRNA content of the host liver. Similarly, the administration of the inactive structural analogue Ro 21-6787 (10-2-(diethylamino)ethyl-9-acridanone) was without any effect. We propose that the actions of Ro 15-5458 and/or its products are directed towards the inhibition of the expression of parasite genes.

A rab-related GTP-binding protein in Schistosoma mansoni.

Schistosomiasis is a parasitic disease initiated by the deposition of eggs in host tissues by the blood fluke Schistosoma. A gene encoding a low-molecular weight GTP-binding protein (LMWGP) was cloned from Schistosoma mansoni using a polymerase chain reaction (PCR)-based strategy. The gene was termed smrab (Schistosoma mansoni rab-related protein). Northern blot analysis hybridizes smrab cDNA with a 1.5-kb band of mRNA; this mRNA is abundantly expressed in male schistosomes, while only slightly in females. The deduced amino acid sequence of smrab shares ca. 70% homology with that of several rab-related LMWGPs. Smrab terminates in a CCXXX motif, which is one of several signals for post-translational isoprenoid modification by geranylgeranyl protein transferase (GGPT) type II. A GGPT assay with in vitro translation product confirms that smrab is geranylgeranylated. Recombinant expression of smrab in the pET3a expression vector yields insoluble protein which migrates as a 23-kDa band on SDS-PAGE. N-terminal sequence information of the recombinant protein matches the predicted amino acid sequence of smrab. GTP-binding analysis indicates that the recombinant protein binds GTP. Therefore, smrab meets the criteria recently established for acceptance into the ras superfamily of GTP-binding proteins (Kahn, R.A., Der, C.J. and Bokoch, G.M. (1992) The ras superfamily of GTP-binding proteins: guidelines on nomenclature. FASEB J. 6, 2512-2513, Ref. [21]).

Characterization of mevalonate-labeled lipids isolated from parasite proteins in Schistosoma mansoni.

Adult paired schistosomes incubated for 3 days in radiolabeled mevalonate can effectively label at least 2 major proteins with apparent sizes of 25 and 43 kDa. The 25-kDa mevalonate-labeled proteins comigrated with proteins that could be labeled with GTP. The lipids attached to these proteins were removed and resolved by HPLC and found to comigrate with known samples of farnesol and geranylgeraniol. Homogenates of the schistosome when incubated with labeled farnesol pyrophosphate effectively labeled a protein(s) with an apparent molecular weight of 43 kDa while homogenates incubated in the presence of labeled geranylgeranyl pyrophosphate-labeled schistosome proteins with an apparent molecular weight of 25 kDa. Our results demonstrate that Schistosoma mansoni has the ability to covalently attach farnesol and geranylgeranyl to low-molecular weight proteins.

Changes in glucose metabolism and cyanide sensitivity in Schistosoma mansoni during development.

Schistosoma mansoni was studied by biochemical and electrophysiological techniques to follow the physiological changes occurring during transformation in the mammalian host. Volume conducted electrical potentials and measurement of CO2 evolution indicate that 3 h post-transformational schistosomula are highly sensitive to cyanide. By 24 h after transformation, evolution of CO2 under control conditions is reduced by 77% from 3 h levels, while lactate excretion rises by 84%. Cyanide does not affect the frequency or magnitude of endogenous electrical transients, but does eliminate 83% of the already reduced levels of CO2 evolved in 24 schistosomula. Electrophysiological analyses indicate that the timecourse of metabolic changes in skin- and mechanically transformed schistosomula are similar, and incubation of schistosomula in 200 micrograms ml-1 puromycin does not alter the onset of cyanide insensitivity. The adult parasite evolves a low level of CO2 which is reduced by 88% in the presence of 1 mM cyanide. No significant Pasteur effect is detected, however, and endogenous electrical activity as well as mechanical responses of the adult musculature are unaffected by cyanide exposure. Our results indicate that schistosomula continue to rely on cyanide-sensitive respiratory components for at least 3 h after transformation; by 24 h, however, the parasites are metabolically similar to the adult stage, i.e., they depend on lactate fermentation for most of their energy requirements.

Patterned expression of BDNF and NT-3 in the retina and anterior segment of the developing mammalian eye.

PURPOSE: The neurotrophins brain-derived neurotrophic factor (BDNF) and neurotrophin-3 (NT-3) are hypothesized to play an important role in vertebrate eye development because of their patterned expression in the developing and adult neuroretina, their regulated response to retinal and optic nerve injury, and the effects of altered neurotrophin signaling on retinal development. To further characterize the role of these neurotrophins in mammalian eye development and maintenance, the pattern of expression of BDNF and NT-3 was analyzed in the developing and mature mouse eye. METHODS: Using mouse strains in which the reporter gene lacZ, encoding the enzyme beta-galactosidase, was targeted to either the BDNF or NT-3 locus, the expression of BDNF and NT-3 in the eyes of mice heterozygous for these mutations was analyzed by enzyme histochemistry during embryogenesis, postnatal development, and adulthood. RESULTS: BDNF and NT-3 expression were first observed in the inner and outer segments of the developing optic cup at embryonic days 10.5 to 11.5. As the retina matured, BDNF expression was restricted to retinal ganglion cells and a subset of cells in the inner nuclear layer (INL), whereas NT-3 expression was confined to a small subset of cells in the INL and ganglion cell layer. Both neurotrophins were expressed within the developing retinal pigment epithelium. In the anterior segment, BDNF and NT-3 were expressed at high levels in the developing and mature ciliary epithelium. In the lens and cornea, however, these neurotrophins displayed distinct patterns of expression during development and adulthood. BDNF expression was found in the lens epithelium, immature trabecular meshwork, corneal endothelium, and corneal epithelium, whereas NT-3 expression was confined to the corneal epithelium. CONCLUSIONS: BDNF and NT-3 exhibit different, yet overlapping, patterns of expression during the development and differentiation of the mouse eye. In addition to the neuroretina, the spatiotemporal expression of BDNF and NT-3 may play an important role in the development and maintenance of the lens, ciliary body, trabecular meshwork, and cornea.

Stability and reproductive fitness of Schistosoma mansoni isolates with decreased sensitivity to praziquantel.

These studies are focused on schistosomes derived from human infections not cured by three successive doses of praziquantel that also produced infections in mice that were significantly more difficult to cure than infections with control worms. Half (three of six) of these isolates retained their decreased response to praziquantel after multiple passages through the life-cycle in the absence of therapeutic pressure. Two of the isolates, including the one initially least sensitive to praziquantel; reverted, to a sensitivity not significantly different from controls. For example, the EE6 isolate initially required 680 mg/kg praziquantel to affect a 50% reduction in worm load in murine infections, but after only six passages through the life cycle over 5 years this was reduced to 113 mg/kg, not different from control infections. The stability of some of the isolates and the reversion of others indicates that the biological or genetic factors conferring decreased praziquantel response varies among the isolates. The three isolates that retained decreased sensitivity to praziquantel all showed compromises in reproductive fitness in the laboratory, expressed most frequently as a decreased cercarial production from snails infected with those isolates compared to controls. For example, the total cercarial production of snails infected with the EE10 isolate was only 57% that of controls. The reversion of some of the isolates to a praziquantel sensitive state and the decreased reproductive fitness of those that did not revert suggest that there is some biological cost associated with the relative praziquantel insensitivity of these worms, which could help limit the impact of such isolates in the field. Infections with the less sensitive isolates also produced significantly less circulating schistosomal antigen in mice, suggesting that a decrease in the host immune response elicited by these worms could be one of the factors contributing to the diminished praziquantel efficacy.

Hydrophilic polyphosphazenes as hydrogels: radiation cross-linking and hydrogel characteristics of poly[bis(methoxyethoxyethoxy)phosphazene].

The water-soluble polyphosphazene, [NP(OCH2CH2OCH2CH2OCH3)2]n, cross-links when exposed to gamma rays to form hydrophilic, water-swellable membranes and hydrogels. The degree of cross-linking increases with irradiation dose in a manner that can be utilized to change the properties. gamma irradiation studies of the small molecule model compound, [NP(OCH2CH2OCH2CH2OCH3)2]4, were also carried out to probe the relationship between irradiation dose and cross-link density.

Synthesis of 2-alkyl- and 2-carboxy-p-tert-butylcalix[4]arenes via the lithiation of tetramethoxy-p-tert-butylcalix[4]arene.

[reaction: see text]. Tetramethoxy-p-tert-butylcalix[4]arene reacts readily with n-butyllithium to give a putative monolithiated intermediate that is substituted with alkyl halides and carbon dioxide to give in 60-75% yield conformationally mobile calix[4]arenes monosubstituted at the methylene bridge (2-position). 2-Alkyl- and 2-benzyl-substituted tetramethoxycalix[4]arenes are converted in 62-68% overall yield to the corresponding tetrahydroxy-p-tert-butylcalix[4]arenes by treatment with boron tribromide. The tetrahydroxy-p-tert-butylcalix[4]arenes exist in the cone conformation at room temperature in CDCl3 as judged by NMR spectroscopy.

Acute sensorimotor polyneuropathy with tonic pupils and an abduction deficit: an unusual presentation of polyarteritis nodosa.

A tonic pupil may occur in isolation or as part of a systemic disorder. We report a patient who developed tonic pupils and an abduction deficit in the setting of polyarteritis nodosa. The combination of a tonic pupil and an abduction deficit should suggest the possibility of a vasculopathic disorder, because the ciliary ganglion and lateral rectus muscle are both supplied by the lateral muscular artery. Widespread small artery and arteriolar narrowing and occlusion are the hallmarks of polyarteritis nodosa. Unusual ischemic syndromes may occur, such as this rare combination of neuro-ophthalmic signs, by involvement of both the nutrient artery and its collaterals. We are unaware of other reports of neuropathic tonic pupils in association with polyarteritis nodosa.

Association of the therapeutic activity of praziquantel with the reversal of Symmers' fibrosis induced by Schistosoma mansoni.

The impact of antischistosomal chemotherapy on the most important complication of intestinal schistosomiasis, Symmers' periportal fibrosis, has not been determined. Since abdominal ultrasonography has proven to be an effective tool in assessing the extent of Symmers' fibrosis in patients, we monitored the effect of chemotherapy, which involved the annual administration of praziquantel, on 48 Sudanese villagers having varying degrees of Symmers' fibrosis. Results indicate no significant differences in the fibrotic status of the 48 patients between 1986 and 1987, but test statistics (both the Wilcoxon signed rank test and Friedman's block/treatment test), indicated a significant decrease between the fibrotic status of the patients in 1986 and their fibrotic status in 1988 and 1989. Thus, after three years of therapy, 12 of the 48 patients no longer had detectable Symmers' fibrosis, while another 16 patients experienced a reduction in the amount of fibrosis in their livers. When coupled with our previous study, which demonstrated that annual treatment of children with praziquantel prevents the appearance of Symmers' fibrosis, it now appears that praziquantel may reverse this schistosomal-induced pathology.

The effects of chronic disulfiram treatment on mice infected with Schistosoma mansoni.

Compounds which block the formation of the egg shell in female schistosomes are thought to have chemotherapeutic value. One of these compounds, disulfiram, when given chronically in the diet produced a 60% reduction in the mortality of mice carrying a heavy schistosome burden. This reduction in mortality was associated with an 80% decrease in granuloma formation. On the other hand, there was no decrease in the amount of periportal inflammation in drug-treated animals. While the use of this drug results in significant amelioration of schistosomal pathology, its effects are rapidly reversible, thus severely limiting its chemotherapeutic potential.

Morbidity associated with Schistosoma mansoni infection as determined by ultrasound: a study in Gezira, Sudan.

Previous studies demonstrated the usefulness of ultrasonography in diagnosing Symmers' periportal fibrosis. The prevalence and grade of Symmers' fibrosis was determined using ultrasonography in two villages in the Gezira region of Sudan and compared to standard clinical criteria. In El Dar 18% and Abu Jin 13% of the population had Symmers' fibrosis by ultrasonography. In contrast, only 6.3% in El Dar and 5.2% in Abu Jin with Symmers' fibrosis had splenomegaly, thus most of the population with Symmers' fibrosis would not have been diagnosed clinically. The degree of involvement was estimated by a set of previously defined criteria which ranged from mild (grade 1) to severe (grade 3). Involvement was greatest between 20-30 years and followed the age peak egg excretion rate by 5 years. The prevalence and degree of splenomegaly as well as the portal and splenic vein diameters increased with grade. The presence of hepatomegaly did not correlate with increasing grade. Ultrasonography is a much more sensitive technique than clinical evaluation in estimating the degree of Symmers' fibrosis in this population. A more accurate assessment of involvement will allow a more rational approach to the study of the pathophysiology of this complication and its eventual control.

Efficacy and tolerance of praziquantel in patients with Schistosoma mansoni infection and Symmers' fibrosis: a field study in the Sudan.

Ultrasonography was used in a village in the Gezira-Managil scheme in the Sudan to identify patients with Symmers' fibrosis. In a random sample from patients with active Schistosoma mansoni infection, 238 patients were found to have no liver involvement while 59 had Symmers' periportal fibrosis. Patients were treated with a single dose of 40 mg/kg body weight of praziquantel. Six months after dosing, 51% and 58% were cured of the infection with 81% and 84% reduction in egg burden in the Symmers' and non-Symmers' patients, respectively. The drug was equally well tolerated by the two groups. It is concluded that patients with Symmers' fibrosis respond to praziquantel and tolerate the drug in a similar manner to patients without Symmers'.