Ultrastructure of spermatogenesis and sperm development in Saccocoelioides godoyi Kohn & Froes, 1986 (Digenea, Haploporidae)

Ultrastructural observations of spermatogenesis and sperm development of Saccocoelioides godoyi, an intestinal parasite of Leporinus friderici (Bloch, 1794) are described. The irregular-shaped spermatogonia form a peripheral layer, and show a prominent nucleus. Spermatocytes are larger than spermatogonia, and in the early stage present synaptonemal complex. Spermatids show nuclei smaller than the spermatocytes. Spermiogenesis is characterized by outgrowth of the zone of differentiation, presenting basal bodies, separated by an intercentriolar body. At the end of this process, the spermatozoa are released into the residual cytoplasmic mass. The spermatozoa of S. godoyi are elongate, similar to the pattern described for other Digenea, showing nuclei, mitochondria and two axonemes with the 9+1 configuration. The peripheral cortical microtubules on the dorsal and ventral faces are laterally interrupted.

Leukocyte integrin expression in patients undergoing cardiopulmonary bypass

BACKGROUND

The recruitment of leukocytes to vascular endothelium is controlled by adhesion events mediated through the beta2 integrins, whereas the response of extravasated leukocytes within the tissues is controlled through the beta1 integrins. Although cardiopulmonary bypass (CPB) has been shown to be associated with a systemic inflammatory response and elevated levels of beta2 integrins on leukocytes, its effect on the beta1 integrins is not known. This study investigated the effect of the protease inhibitor aprotinin on the expression of the beta1 and beta2 integrins on circulating leukocytes in patients undergoing CPB.

METHODS

Patients undergoing primary elective coronary artery bypass grafting were randomized into full-dose aprotinin or placebo groups. Blood samples were obtained at nine time points preoperatively, intraoperatively, and up to 6 days postoperatively. The surface expression of the beta1 integrins VLA-1, -3, -4, -5, and -6 and of the beta2 integrins CD11a/CD18, CD11b/CD18, and CD11c/CD18 was measured by flow cytometry on gated neutrophil and monocyte subpopulations in whole blood.

RESULTS

Expression of the beta1 integrins was not significantly altered during the study period and, therefore, aprotinin had no effect on the expression of these molecules. Of the beta2 integrins, CD11b/CD18 expression was significantly increased on neutrophils at 15 minutes after onset of CPB in the placebo group (p < 0.01) but not in the aprotinin group.

CONCLUSIONS

This study showed that expression of the beta1 integrins on neutrophils and monocytes did not alter during the first 6 days after CPB. Expression of the beta2 integrin CD11b/CD18 increased significantly on neutrophils during CPB in control patients but not in patients treated with full-dose aprotinin.

[Treatment of perianal Crohn's disease]

Perianal Crohn's disease (PACD) is defined as the presence of persistent lesions in the anal canal and perianal region in patients with Crohn's disease. The relative incidence of PACD in Crohn's disease patients ranges from 15 to 80% in the literature, depending on the accuracy of the clinical investigations and the clinical importance attributed to the lesions in the various study populations. The incidence is significantly higher if the intestinal disease is located in the colon-rectum rather than in the small bowel. We reviewed our experience in 105 patients with PACD, 32 of whom presenting rectal localisation of the primary disease. We observed 2 stenoses, 3 perirectal abscesses, 3 rectal ulcerations, 5 skin tags, 10 fissures and 77 fistulas. Two dilatations under narcosis, 2 intrarectal drainages of abscesses, 19 fistulotomies, 7 partial fistulotomies and insertion of loose setons, 47 loose setons and 4 anoperineal diversions were performed. The remaining patients received medical and topical treatments. After a median follow-up of 30 months, 90 patients (86%) showed a good response with improvement in functional scores, while 15 (14%) showed no improvement or a worsening requiring proctectomy in 13 cases. All patients submitted to proctectomy had rectal localization of the disease.

Functional neocortical microcircuitry demonstrated with intrinsic signal optical imaging in vitro

Intrinsic signal optical imaging was used to record the changes in light transmittance evoked by electrical stimulation in slices prepared from sensorimotor cortex of young adult rats. The spatial characteristics of the optical signal evoked by stimulation of layer II/III, IV, V, or VI were clearly different. Layer IV and V stimulation elicited a radially-oriented region of increased light transmittance which was "hourglass" shaped: its tangential extent was greatest in layers II/III and layer V, and least in layer IV. Layer VI stimulation also elicited a radially-oriented signal but the tangential extent of this signal was the same across layers II-VI--that is, it was column-shaped. Upper layer stimulation produced a signal whose tangential extent was much greater in the upper layers than its radial extent to the deeper layers. The spatial form of the stimulus-evoked intrinsic signal was not dependent on the cytoarchitectonic area in which it was elicited. The tangential and radial distribution of the signal evoked by stimulation of different layers appears to reflect the connectivity of cortex, particularly the horizontal connectivity present in layers II/III, V, and VI, and the interlaminar connections that exist between layers II/III and V and from layers VI to IV. The spatial characteristics of the intrinsic signal were independent of the strength of stimulation used. The idea that inhibitory mechanisms restrict the tangential extent of the signal was evaluated in experiments in which the intrinsic signal was recorded before and after the addition of 10 microM bicuculline methiodide. In all slices studied in this way (n = 12), bicuculline methiodide drastically increased the tangential extent of the signal. In 4/12 slices, the tangential spread of the signal was asymmetric with respect to the stimulus site. Asymmetric spread of the signal occurred for both layer V and layer VI stimulation and, in 2/4 of those cases, could be attributed to a cytoarchitectonic border whose presence appeared to restrict the spread of the signal across the border. Although increasing stimulation strength did not change the spatial characteristics of the radially-oriented signal evoked by layer V or VI stimulation, at maximal stimulus intensity the signal evoked from these layers was often accompanied by a band of decreased light transmittance in the most superficial layers (layers I and II). It is concluded that in vitro intrinsic optical signal imaging allows one to image a response attributable to activation of local subsets of cortical connections. In addition, the opposite effects of high-intensity deep layer stimulation on the superficial layers vs layers III-VI of the same column raise the possibility that the most superficial layers may respond differently to repetitive input drive than the rest of the cortical column.

Chalcinotrema thatcheri n. sp. (Digenea: Haploporidae) from Brazilian freshwater fishes, a redescription of C. ruedasueltensis Thatcher, 1978 and comments on the validity of the genus

Chalcinotrema thatcheri n. sp. from the intestine of Schizodon knerii is described. It is most closely related in general morphology to C. salobrensis Freitas, 1947 and C. ruedasueltensis Thatcher, 1978, from which it differs, respectively, in: testis-size, the distribution of the vitelline follicles and the distance between the gonads; and body-size, egg-size, the extent of the caeca and the shape of the seminal vesicle. The holotype of C. ruedasueltensis is redescribed with original figures. Chalcinotrema Freitas, 1947, is considered a good genus distinct from Carassotrema Park, 1938, on the basis of the presence of uterine loops between the ovary and testis and its totally different geographical distribution. Carassotrema tilapiae Nasir & Gomez, 1976 is transferred to the former genus as Chalcinotrema tilapiae (Nasir & Gomez, 1976) n. comb.

Spermatogenesis and spermiogenesis in Microcotyle sp. (Microcotylidae, Monogenea)

Ultrastructural observations of spermatogenesis and spermiogenesis in Microcotyle sp. a microcotylid monogenean parasite from the gills of Hypostomus sp., are described. The spermatogonia were irregularly shaped, forming a peripheral layer of cells; spermatocytes were larger than spermatogonia and a nuclear synaptonemal complex was observed; young spermatids were joined by a central cytophore forming rosettes. Spermiogenesis was characterized by the outgrowth of a cytoplasmic protuberance, the zone of differentiation, containing the basal bodies, separated by an intercentriolar body, from which flagella grow out and fuse posteriorly with the median process. Cross sections of the anterior and the middle regions of spermatozoa revealed nuclei, mitochondria, peripheral microtubules, and paired axonemes each with a 9+1 pattern.

Prospective evaluation of transabdominal bowel sonography in the diagnosis of intestinal obstruction in Crohn's disease: comparison with plain abdominal film and small bowel enteroclysis

Transabdominal ultrasonography is a noninvasive, radiation-free method that is well tolerated by patients with acute abdominal symptoms. The aim of this study was to investigate the validity of transabdominal ultrasonography, compared with plain abdominal film and small bowel enteroclysis in the diagnosis of small bowel obstruction in patients with Crohn's disease (CD). Forty-four patients with CD ileitis or ileocolitis and acute obstructive symptoms who received ultrasonography and plain abdominal film at hospital admission were evaluated by small bowel enema before dismissal or surgery and were considered for statistical analysis. Small bowel obstruction was diagnosed by ultrasonography in 23 of 44 patients (52%), by plain abdominal film in 26 of 44 patients (59%), and by small bowel enema in 28 of 44 patients (64%); the diagnostic accuracy of plain abdominal film and ultrasonography compared with small bowel enema was 73% and 89%, respectively. Ultrasonography proved to be highly specific (100%) with no false positive results. Surgery performed in 25 of 44 patients for symptoms refractory to medical treatment confirmed the high diagnostic value of ultrasonography. The result of this study indicates that transabdominal ultrasonography is accurate and highly specific in the diagnosis of small bowel obstruction and can be considered a valuable first choice examination in CD patients with obstructive symptoms.

New data on Oncophora melanocephala (Nematoda: Camallanidae), a little-known parasite of scombrid fishes

The camallanid nematode Oncophora melanocephala (Rudolphi, 1819) is redescribed from specimens collected in tunas, Thunnus thynnus (L.), T. albacares (Bonnaterre), T. atlanticus (Lesson) and Auxis thazard (Lacépède) from the Atlantic littoral of Rio de Janeiro, Brazil. In addition to a specific structure of the buccal capsule, the species is characterized by the presence of seven pairs of preanal and five pairs of postanal subventral papillae in the male and by an unusual shape of body in the adult female; deirids are described for the first time in O. melanocephala. The structure of the buccal capsule of O. melanocephala, particularly the presence of a large posterior portion of capsule and a colourless connecting ring between buccal capsule and oesophagus, shows close affinities of Oncophora Diesing, 1851 with Paracamallanus Yorke et Maplestone, 1928. The findings of O. melanocephala in T. atlanticus and A thazard represent new host records.

Molecular studies define the primary structure of alpha1-antichymotrypsin (ACT) protease inhibitor in Alzheimer's disease brains. Comparison of act in hippocampus and liver

An alpha1-antichymotrypsin-like serpin has been implicated in Alzheimer's disease (AD) based on immunochemical detection of alpha1-antichymotrypsin (ACT) in amyloid plaques from the hippocampus of AD brains. The presence of neuroendocrine isoforms of ACTs and reported variations in human liver ACT cDNA sequences raise the question of the molecular identity of ACT in brain. In this study, direct reverse transcription-polymerase chain reaction and cDNA sequencing indicate that the hippocampus ACT possesses the reactive site loop that is characteristic of serpins, with Leu as the predicted P1 residue interacting with putative chymotrypsin-like target proteases. The deduced primary sequence of the human hippocampus ACT possesses more than 90% homology with reported primary sequences for the human liver ACT. Moreover, identical ACT primary sequences deduced from the cDNAs were demonstrated in the hippocampus of control and AD brains. Northern blots showed that ACT mRNA expression in hippocampus was 900 times lower than that in liver. Also, hippocampus and liver ACT proteins demonstrated differential sensitivities to deglycosylation. Overall, reverse transcription-polymerase chain reaction combined with cDNA and primary sequence analyses have defined the molecular identity of human hippocampus ACT in control and AD brains. The determined reactive site loop domain of hippocampus ACT will allow prediction of potential target proteases inhibited by ACT in AD.

[Therapeutic evaluation of artesunate in experimental Schistosoma mansoni infection]

Mice experimentally infected with Schistosoma mansoni were treated orally with artesunate (Lactab) in a single dose of 300 or 500 mg/kg or over a period of five consecutive days. The animals were sacrificed 7, 30, 60 or 90 days after treatment. Statistically significant differences were found in the distribution and mortality of the worms and in the alterations of the oogram in the treated group when compared to control in all of the tested schemes when the animals were sacrificed 30 days after treatment. Morphological analysis of female worms showed a reduction of ovarian volume and rarefaction of the vitelline follicles. These modifications were more marked after treatment with the higher dose, explaining the alteration of the oogram which reached 100%. However, when the animals were sacrificed 60 or 90 days after treatment, the differences and alterations were smaller, showing that the surviving worms recovered and restarted oviposition.

South American Monogenea--list of species, hosts and geographical distribution

Five-hundred and twenty-three species of monogeneans have been recorded in South America: 43 from Argentina, one from Bolivia, 252 from Brazil, 29 from Chile, 15 from Colombia, eight from Ecuador, 26 from Falkland and Patagonian regions, four from French Guyana, 11 from Galapagos, two from Guiana, four from Paraguay, 92 from Peru, 16 from Uruguay and 20 from Venezuela. A list of these species with hosts and geographical distribution is presented.

Didactic and experiential education in substance abuse programs

Medical model and social model programs both include client education as part of their service mandate, although the two models may define and accomplish the task of education differently. The role of education in substance abuse recovery has not been clear in either the treatment or recovery models. This paper therefore begins with a debate of the value of "educating" substance abuse clients, using several possible definitions of education and drawing upon a variety of theories from health education and community psychology. We divide these types of education into two broad definitional categories: knowledge acquisition and life skills development. Using data collected during a process evaluation at one medical and two social model programs, we provide examples of how knowledge acquisition and life skills development are accomplished at these sites. Analysis of the observational data pointed to two approaches to education, one didactic, the other experiential. All three sites used a didactic approach to knowledge about addiction. Only the social model sites used an experiential approach to convey knowledge and skills about recovery, and the development of life skills.

Optical imaging in vitro provides evidence for the minicolumnar nature of cortical response

The response of rat neocortical slices to electrical stimulation at the layer VI/white matter border was recorded using intrinsic signal optical imaging. The optical response of the slice is column-shaped, extends from layer VI to the pial surface, and is strongly correlated with the amplitude of simultaneously recorded evoked potentials. Spectral analysis revealed radially oriented spatial variations in the intensity of the optical signal with a period of 30-60 microm/cycle. Nissl-stained sections of slices also exhibited a radially oriented periodicity in optical density with the same period. We conclude that the periodic variations in the intrinsic optical signal correspond to stimulus-activated minicolumns.

New observations on seuratoid nematodes parasitic in fishes of the Paraná River, Brasil

The present paper comprises a systematic survey of nematodes of the superfamily Seuratoidea collected from fishes of the Paraná River, southern Brazil, in 1992-1995. The following species were recorded: Neoparaseuratum travassosi Moravec, Kohn et Fernandes, 1992, Spectatus sp., Seuratoidea gen. sp. larvae, Cucullanus brevispiculus Moravec, Kohn et Fernandes, 1993, C. pinnai pinnai Travassos, Artigas et Pereira, 1928, C. pinnai pterodorasi subsp. n., C. rhamphichthydis sp. n., C. zungaro Vaz et Pereira, 1934, and Dichelyne pimelodi sp. n. C. pinnai pterodorasi (type host Pterodoras granulosus) differs from C. p. pinnai in the shape of the oesophagus and in the position of the nerve ring. C. rhamphichthydis (only females) (type host Rhamphichthys rostratus) is characterized mainly by the postoesophageal position of the excretory pore and deirids, complex structure of the cuticular lining of oesophastome and by markedly narrow body, whereas D. pimelodi (one male) (type host Pimelodus sp.) by the length of spicules (1.46 mm), postoesophageal position of the excretory pore and deirids and by the arrangement of genital papillae. Most species are briefly described (females of C. brevispiculus and Seuratoidea gen. sp. larvae for the first time) and illustrated and some problems concerning their taxonomy, hosts and geographical distribution are discussed.

High-level expression of the prohormones proenkephalin, pro-neuropeptide Y, proopiomelanocortin, and beta-protachykinin for in vitro prohormone processing

Prohormone substrates are required for investigation of the proteolytic processing of prohormones and proproteins into active peptide hormones and neurotransmitters. However, the lack of prohormone proteins has been a limiting factor in elucidating proteolytic mechanisms for conversion of prohormones into active peptides. Therefore, in this study, cloned cDNAs encoding the prohormones proenkephalin (PE), pro-neuropeptide Y (pro-NPY), pro-opiomelanocortin (POMC), and beta-protachykinin (beta-PT) were utilized to express recombinant prohormones in Escherichia coli. High-level expression of milligrams of prohormones was achieved with the pET3c expression vector utilizing the T7 promoter for production of PE, pro-NPY, and POMC, as demonstrated by SDS-PAGE gel electrophoresis, Western blots, and 35S-methionine labeling. In addition, beta-PT was expressed at high levels as fusion proteins with the maltose-binding protein and glutathione S-transferase by the pMAL-c and pGEX-2T expression vectors, respectively. Relative rates of processing by the established processing proteases "prohormone thiol protease" (PTP), 70-kDa aspartyl protease, and PC1/ 3 and PC2 (PC, prohormone convertase) were examined with purified PE, pro-NPY, and POMC. Distinct preferences of processing enzymes for different prohormones was demonstrated. PTP preferred PE and pro-NPY substrates, whereas little processing of POMC was detected. In contrast, the 70-kDa aspartyl protease cleaved POMC more readily than pro-NPY or PE. However, PC1/3 and PC2 prefer POMC as substrate. Demonstration of selectivity of processing enzymes for prohormone substrates illustrates the importance of expressing recombinant prohormones for in vitro processing studies.

An antibiotic regimen for the treatment of active Crohn's disease: a randomized, controlled clinical trial of metronidazole plus ciprofloxacin

OBJECTIVES

Bacteria in the gut lumen may play a role in the etiology and/or the symptoms of Crohn's disease (CD). Although various antibacterial drugs have been employed in clinical practice, few controlled trials have been conducted, and those had conflicting results. The aim of this study was to investigate the efficacy and the safety of a combination of metronidazole and ciprofloxacin, compared with methylprednisolone, in treating 41 consecutive patients with active CD.

METHODS

Eligible patients, 13 men and 28 women, mean age 38 yr, were randomly allocated to receive, for 12 wk, ciprofloxacin 500 mg twice daily plus metronidazole 250 mg four times daily or methylprednisolone 0.7-l mg/kg/day, with variable tapering to 40 mg, followed by tapering of 4 mg weekly.

RESULTS

Ten of the 22 antibiotic patients (45.5%) and 12 of the 19 steroid patients (63%) obtained clinical remission (Crohn's Disease Activity Index < or = 150) at the end of the 12-wk study (p = NS). Five patients on antibiotics (22.7%) and five patients on steroids (26.3%) were considered treatment failures because of deterioration or persistent symptoms. Six patients receiving antibiotics (27.3%) and two on steroids (10.6%) were withdrawn from the trial because of side effects. One patient on antibiotics was not compliant.

CONCLUSIONS

metronidazole and ciprofloxacin could be an alternative to steroids in treating the acute phase of CD.

Ultrastructural aspects of spermatogenesis in Metamicrocotyla macracantha (Alexander, 1954) Koratha, 1955 (Monogenea; Microcotylidae)

Ultrastructural aspects of spermatogenesis, spermiogenesis and of the mature spermatozoon of a microcotylid monogenean Metamicrocotyla macracantha parasite from Mugil liza, are described. The irregularly-shaped spermatogonia divides by successive mitoses, forming the primary spermatocytes, identified by the presence of synaptonemal complexes in their nuclei. The spermatids formed by meiotic cell divisions of the secondary spermatocytes, differentiate into a mature spermatozoon. Cross sections of the head and the middle region of mature spermatozoa show the nucleus with strong condensed chromatin, the mitochondria with short cristae, peripheral microtubules and two axonemes with a 9 + 1 pattern, confirming the characteristics of this genus.

Scanning electron microscopic study of Prosorhynchoides arcuatus (Linton, 1990) (Bucephalidae: Digenea)

Prosorhynchoides arcuatus (Linton, 1900) from the intestine of Pomatomus saltator (L.) from the Atlantic coast of the State of Rio de Janeiro is studied by scanning electron microscopy, with detailed description of tegumental spines. Comments on the synonymy of this species with Bucephalopsis callicotyle Kohn, 1962 are made. The tegument of adult P. arcuatus presents scale like and serrated spines and uniciliated sensory papillae, distributed over the body surface and is compared with other digenetic trematodes.

Structure of the cephalic end of two little-known oxyuroid genera, Travnema Pereira, 1938 and Cosmoxynemoides Travassos, 1949, parasites of fishes, as revealed by SEM

The cephalic end of the type species of pharyngodonid genera Travnema and Cosmoxynemoides, T. travnema Pereira, 1938 and C. aguirrei Travassos, 1949, parasites of Brazilian freshwater fishes, was studied by scanning electron microscopy. The mouth aperture of Travnema was found to be circular, surrounded by four cephalic papillae and two lateral amphids and the cuticle of the cephalic end had a conspicuous dense sculpture. On the other hand, the mouth aperture of Cosmoxynemoides was triangular, surrounded by three lip-like elevations covering the whole surface of the relatively flat cephalic extremity, each with two inner lobes separated one from another by a short groove; the lip-like elevations bore four medium-sized, kidney-shaped cephalic papillae and two minute amphids (two papillae on the dorsal elevation and one papilla and one amphid on each of two ventrolateral elevations); the cuticle of the cephalic end was smooth. Both species were noted for the absence of oral lamellae and the presence of lateral alae. Both genera are listed in the family Pharyngodonidae but Travnema (and also Hakynema), due to its morphological peculiarities, is considered to represent a distinct subfamily Travnematinae within the Pharyngodonidae. The finding of both T. travnema and C. aguirrei in the characid fish Astyanax bimaculatus lacustris represents new host records.

Antimycobacterial therapy in Crohn's disease: results of a controlled, double-blind trial with a multiple antibiotic regimen

Several recent reports have suggested an association of atypical mycobacteria with Crohn's disease.

OBJECTIVES

The goal of this double-blind, placebo-controlled trial was to determine the efficacy of treatment with antimycobacterial drugs in maintaining clinical remission and in reducing active inflammatory lesions.

METHODS

Forty patients (15 male) with refractory, steroid-dependent Crohn's disease were randomized to receive 2 months of tapering steroids plus either a 9-month regimen of ethambutol, clofazimine, dapsone and 1-day dose only of rifampicin (n = 22), or identical placebo.

RESULTS

Three patients (two on active drug) were unable to discontinue steroids, and one patient on active drug was withdrawn for side effects during the first 2 months. Three of the remaining 19 patients on active drug relapsed during the study period, compared with 11 of 17 on placebo (log likelihood ratio = 4.6; p = 0.03). Another patient was withdrawn in remission at 5 months for anemia related to dapsone. Nine patients whose disease relapsed or persisted on placebo were crossed over to active drug; five achieved sustained remission, two failed, and two were withdrawn for side effects. Substantial endoscopic or radiologic healing did not occur.

CONCLUSION

This study suggests that the treatment regimen with rifampicin, ethambutol, clofazimine, and dapsone is effective in relief of symptoms and maintenance of remission in some Crohn's disease patients.