Observations on Onchocerca volvulus in experimentally infected chimpanzees

The paper describes observations made on 32 chimpanzees experimentally infected with Onchocerca volvulus. The mean pre-patent intervals for the Cameroon forest and the Guatemalan strains of O. volvulus were 13-16 months and 12-15 months respectively. That for the Cameroon Sudan-savanna strain was much longer, i.e. 22-23 months. The numbers of microfilariae found in the skins of animals infected with the Cameroon Sudan-savanna strain were also much lower than in animals infected with the other two strains. Long-term observations on infected animals showed that microfilarial infections had virtually died out 6.5-9 years after the last inoculation with infective larvae. Those animals which were inoculated with infective larvae in the head or above the waist tended to show a higher proportion of microfilariae in the upper parts of the body, than did those inoculated with infective larvae below the waist. In animals which showed adult worm-bundles on only one side of the body, the concentration of microfilariae was usually greater on that side of the body. Worm-bundles in the chimpanzee varied in size from 8 x 5 x 2 mm to 4 x 3 x 2 cm. Out of 47 worm-bundles found, only two were subcutaneous. The remainder lay deep in the tissues, most commonly adjacent to the posterior surface of the capsule of the hip joint. No onchocerciasis eye lesions were seen in any of the infected animals.     

Polymerase chain reaction-based diagnosis of Onchocerca volvulus infection: improved detection of patients with onchocerciasis

Definitive diagnosis of Onchocerca volvulus (Ov) infection requires the identification of the parasite in either the skin or subcutaneous nodules. These parasitologic approaches suffer from poor sensitivity. To assess the efficacy and utility of a polymerase chain reaction (PCR)-based diagnosis for Ov infection, skin snips were examined from 94 persons in an Ov-endemic region of Ecuador, and results were compared in a blinded fashion with those of a PCR assay based on the Onchocerca-specific repetitive DNA sequence, O-150. All 60 patients microfilaria-positive on skin snip examination were positive in the PCR-based assay. In addition, 13 of 34 who were microfilaria-negative by skin snips were positive in the PCR assay. This suggests that the PCR-based assay is significantly more sensitive than current methods and overcomes many deficiencies of parasitologic and serologic methodologies in diagnosing active onchocerciasis.     

Adult Onchocerca volvulus from east and west Africa exhibit similar antigenicity with pooled sera from onchocerciasis patients

Gonorrhea is still a major sexually transmitted disease (STD) worldwide. Its etiologic diagnosis is based on identification of the causative agent, Neisseria gonorrhoeae, by culture of genital secretions, which is often hampered by difficulties of sample collection and transport. Alternatively, nucleic acid hybridization techniques for routine diagnosis of N. gonorrhoeae appear to be useful by eliminating problems associated with bacterial viability, particularly for surveillance of low-prevalence populations. Our study among 1,508 outpatients undergoing routine examination for common STDs used RNA/DNA hybridization with a DNA probe specific for N. gonorrhoeae (Gen Probe Pace 2) and classical culture. Of the 1,750 specimens tested, 12 were positive by DNA probe and culture. In 8 cases, only DNA probe was positive while culture was negative. In 3 of these discrepant cases clinical and epidemiological data suggested true N. gonorrhoeae infection. Thus, DNA probe assay for N. gonorrhoeae may greatly improve screening of N. gonorrhoeae among low-prevalence populations. However, culture remains mandatory for testing antimicrobial resistance of these highly communicable infectious agents.     

T cell responses in coinfection with Onchocerca volvulus and the human immunodeficiency virus type 1

Onchocerca volvulus and the human immunodeficiency virus (HIV) are two immunocompromising infectious agents of major public health concern in Uganda. To examine the effect of coinfection with O. volvulus and HIV on cellular immune responses, lymphocyte proliferative responses and cytokine production of peripheral blood mononuclear cells (PBMC) from persons infected with O. volvulus with and without HIV type 1 infection were compared. Proliferation of PBMC to PHA and tuberculin (PPD) in coinfection was less (P = 0.08, P < 0.01) than in O. volvulus infection. O. volvulus extract stimulated lymphocyte proliferation in microfilaria-negative and HIV-negative O. volvulus infection while only an inconspicuous response was observed in microfilaria-negative coinfection. After stimulation of PBMC with PPD, the production of interferon-gamma (IFN-gamma), interleukin (IL)-4 and IL-5-demonstrated in O. volvulus infection-were reduced in coinfection with HIV (P < 0.01). While both groups failed to produce IFN-gamma in response to O. volvulus extract, only O. volvulus infected persons generated pronounced IL-5 and low IL-4 levels (0.01 > P = 0.02). The cellular immune responses in coinfection suggested an HIV-related lack of specific reactivity to O. volvulus antigen and impairment of IL-4 and IL-5 production in addition to the lack of IFN-gamma response on antigenic stimulation.     

Seasonal variation in the concentration of Onchocerca volvulus microfilariae in the skin?

Repeated multiple skin snips in 18 persons with onchocerciasis from the Sudan-savanna of West Africa suggested the possibility of a seasonal variation in microfilarial concentrations. This variation may be an evolutionary adaptation of the parasite to the climate conditions that affect the seasonal distribution of the vector, but a migration of the microfilariae in the skin layers caused by the Simulium bites cannot be excluded.     

The ''in vitro'' effect of diethylcarbamazine on the motility and survival of Onchocerca volvulus microfilariae

This paper presents a tested approach to a systematic progression of learning from the classroom to the clinical internship. The approach uses workbooks to integrate all facets of the training continuum. The basic model is training continuum. The basic model is called TAR. T refers to theory or teaching; A to application, which occurs during the clinical component; and R to reinforcement provided through seminars scheduled concurrently with fieldwork. The entire concept is introduced to students during a required weekly fieldwork preparation component scheduled prior to the first theory course. Clinicians and academicians participated in all phases of the three-year, HEW-funded project, which included development of interrelated performance objectives for the teaching, application and reinforcement components. Analysis of data from clinicians, students and faculty indicated that the TAR model provides a needed integrating structure.     

Characterization of a recombinant Onchocerca volvulus antigen (Ov33) produced in yeast

A yeast (Saccharomyces cerevisiae) expression system has been adapted to produce reagent quantities of a major Onchocerca antigen, Ov33. Using a pool of monoclonal antibodies produced against third-stage larvae, a cDNA library constructed from adult O. volvulus worms was screened. Twenty-seven cDNAs were isolated, two of which had sequence homology to Ov33, a putative aspartyl protease inhibitor, which is the immunodominant antigen of O. volvulus. These cDNAs were expressed at high levels intracellularly or through the secretory pathway of S. cerevisiae. Localization studies using antisera produced against purified recombinant protein demonstrated that Ov33 is a very abundant parasite protein present in the hypodermis, muscle, and uterus of female worms, as well as in embryonic microfilariae. The soluble recombinant protein secreted by yeast (C71) demonstrated inhibitory activity against the aspartyl protease pepsin. Antibodies to the recombinant protein-mediated leukocyte adherence to and killing of skin microfilariae. The sensitivity of a diagnostic test using recombinant Ov33 was evaluated using sera from 441 patients. The mean sensitivities for the two recombinant constructs, C27 and C71, were 82.2% and 85.4%, respectively. The combined sensitivity using both recombinant proteins was 94%.     

PCR and DNA hybridization indicate the absence of animal filariae from vectors of Onchocerca volvulus in Uganda

In order to identify Onchocerca volvulus larvae from vectors, DNA of filaria larvae from dissected blackflies was isolated, and a 150-bp long tandemly repeated DNA sequence (0-150), which occurs in many Onchocerca species, was amplified using polymerase chain reaction (PCR). Subsequently, the PCR product was blotted onto a nylon membrane and hybridized with DNA probes specific for O. volvulus or Onchocerca ochengi. Filaria larvae from 395 infected Simulium neavei were examined and 259 samples produced detectable PCR products. Among these samples, 239 (92%) reacted with an O. volvulus-specific oligonucleotide. A sample of 69 PCR products was tested using an O. ochengi DNA probe, but all failed to hybridize. Filaria larvae from 64 infected Simulium damnosum, presumably of the cytotypes "Nyamagasani" and "Nkusi" were studied and 0-150 was amplified from 38 samples. From these samples, 35 (92%) hybridized specifically with an O. volvulus probe but none with the O. ochengi-specific DNA sequence. Nonamplified samples were obtained mainly from blackflies that contained only 1 or 2 filaria larvae, and therefore, an insufficient DNA extraction was assumed. It can be concluded that few, if any, filaria species of animal origin were transmitted by S. neavei and S. damnosum s.l. in Kabarole and Kasese districts in Uganda.     

The peroxidoxin 2 protein of the human parasite Onchocerca volvulus: recombinant expression, immunolocalization, and demonstration of homologous molecules in other species

The peroxidoxin protein of the filarial parasite Onchocerca volvulus (OvPXN-2) belongs to a group of highly conserved antioxidant molecules. For a more detailed characterization of this protein and for determination of its expression pattern the OvPXN-2 protein was recombinantly expressed as a His-tagged protein. Under reducing conditions the recombinant protein had an apparent molecular mass of 28 kDa. Considering the size of the His-tag and the FLAG epitope introduced to the recombinant protein, this size is in agreement with that of the native protein identified in O. volvulus extract. Antiserum raised against the recombinant protein was used for immunolocalization. In O. volvulus the antigen is predominantly expressed in the hypodermis and particularly the lateral and median chords show high levels of expression. The protein is also expressed strongly in the hypodermis of infective larvae and more weakly in microfilariae. Related cross-reacting proteins were detected in several Onchocerca species and other filariae. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis in combination with Western blotting revealed proteins with almost identical mobility in extracts prepared from O. ochengi, O. gibsoni, and Dirofilaria immitis.     

Studies on Bancroftian filariasis in Liberia, West Africa. IV. Notes on side effects observed during a diethylcarbamazine treatment campaign in a rural area endemic for Wuchereria bancrofti and Onchocerca volvulus

464 persons of whom 189 proved to be infected with microfilariae of Wuchereria bancrofti and/or Onchocerca volvulus were examined for adverse reactions due to diethylcarbamazine, which was administered during a filariasis control campaign. Persons older than 20 years of age were significantly more affected than younger persons and men showed distinctly more side effects than women. The most frequent complaints were skin reactions followed by gastrointestinal complications. The significantly highest rate of adverse reactions was observed in persons being infected with microfilariae of O. volvulus, whereas no significant difference was registered between side effect rates of bancroftian microfilaria carriers and non-infected persons. It is concluded that in areas where both filarial species are endemic, infections with O. volvulus are a limiting factor for the control of bancroftian filariasis by means of mass treatment with diethylcarbamazine.     

Effect of pravastatin treatment on glucose, insulin, and lipoprotein metabolism in patients with hypercholesterolemia

Treatment of patients with type IIA hyperlipoproteinemia (HLP) with pravastatin for 3 months led to significant decreases (p < 0.001) in total cholesterol (7.18 +/- 0.30 to 5.75 +/- 0.30 mmol/L), LDL cholesterol (5.56 +/- 0.33 to 4.02 +/- 0.32 mmol/L), and ratio of total cholesterol to HDL cholesterol (6.5 +/- 0.4 to 4.6 +/- 0.4). Decreases of a similar magnitude were also seen in patients with type IIB HLP. Plasma glucose and insulin concentrations after an oral glucose load and from 8 AM to 4PM in response to meals were higher in patients with Type IIB HLP, who also had higher steady-state plasma glucose concentrations after an infusion of somatostatin, insulin, and glucose (12.4 +/- 1 vs 5.5 +/- 0.8 mmol/L, p < 0.001). Because steady-state plasma insulin concentrations were similar in both groups, patients with type IIB HLP were relatively insulin resistant. Furthermore, day-long plasma glucose concentrations and insulin resistance were modestly, but significantly (p < 0.01), greater after treatment in both groups. In conclusion, LDL cholesterol metabolism improved in hypercholesterolemic subjects treated with pravastatin, but the hypertriglyceridemia, insulin resistance, relative glucose intolerance, and hyperinsulinemia present in patients with type IIB HLP either did not improve with treatment or was somewhat worse.     

Localization and functional analysis of the cytosolic and extracellular CuZn superoxide dismutases in the human parasitic nematode Onchocerca volvulus

This study describes the histological localization of two CuZn superoxide dismutases (SOD1 and SOD2) in the parasitic nematode Onchocerca volvulus, and a functional characterization of the 'extracellular' form of this enzyme (SOD2) which provides evidence that it is involved in the defense against environmental superoxide anion radicals. These essential enzymes are detected in larval and adult stages of the parasite, determined at the mRNA and protein levels by in situ hybridization and immunolocalization studies. These proteins are distributed throughout the worm, at various concentrations with particularly high levels produced in the hypodermis. In vitro maintenance of parasites indicated that SOD2 was secreted outside the parasite into the medium. Baculovirus constructs designed to test the ability of the SOD2 hydrophobic N-terminal region to function in processing and secretion confirmed the ability of this polypeptide sequence to direct the secretion of a marker protein, as well as of the mature SOD2 enzyme. Analyses of the native, mature SOD2 enzyme molecular mass, and the primary and quaternary structure, indicate that unlike other extracellular SODs, the SOD2 is active as a non-glycosylated dimer, rather than as a tetrameric glycoprotein. The detection of SOD2 outside of the parasite maintained in vitro, and the confirmation that the SOD2 is a secreted enzyme, indicate that this enzyme plays a role in the interactive biology of parasitic nematodes with their hosts.     

pOVEX vector: prokaryotic expression and purification of onchocerciasis vaccine candidate antigens as fusion proteins with the 24 kD Onchocerca volvulus glutathione S-transferase

We describe a 42-year-old male patient with a primitive peripheral neuroectodermal tumor (PPNET) arising from the kidney. The patient was treated sequentially with surgery, radiotherapy, experimental cytokine treatment (rhIL-6), combination chemotherapy and consolidated in complete remission with high-dose chemotherapy, supported by autologous stem cells (AST) and hematopoietic growth factors. The patient remains in complete remission at 34+ months after AST and is surviving disease-free for five years after initial presentation. The case presented here is unusual because of the renal origin and the long remission duration and survival when compared with the usual outcome of adult metastatic PPNET. High-dose chemotherapy may have favorably influenced the outcome in this patient. The case is discussed in the context of the general treatment of metastatic PPNET.     

Effect of chemoprophylaxis with an ivermectin sustained-release bolus on acquired resistance to gastrointestinal parasites in cattle

The influence of chemoprophylaxis with an ivermectin sustained-release bolus in the first grazing season on the resistance of cattle to gastrointestinal nematodes during the following grazing season was investigated. In 1993 and 1994 dairy replacement calves were either given one bolus at the start of their first grazing season or left untreated. The two groups were grazed separately on a pasture that was divided into two similar sized paddocks. Faecal egg counts, serum pepsinogen and antibody levels were measured to evaluate host-parasite contact. Pasture infection levels were estimated by pasture larval counts and worm counts in tracer calves. After winter housing the animals were monitored during their second grazing season on a pasture that was also divided into two similar sized paddocks. Acquired resistance to gastrointestinal nematodes was evaluated by faecal egg counts and weight gains. Again, pasture infection levels were determined and pepsinogen and antibody levels were measured. During the first grazing seasons gastrointestinal nematode infections were controlled very effectively by the bolus, as shown by the greater weight gains, the negligible faecal egg counts and the low serum pepsinogen and antibody levels in the treated calves. In contrast, all parameters showed extensive parasite-host contact in the untreated animals. The efficient prophylaxis in the treated groups resulted in low levels of larval contamination on the paddocks grazed by the treated animals, compared to moderate infection levels at the end of both first grazing seasons on the paddocks grazed by the untreated animals. During the second grazing seasons (1994 and 1995) the faecal egg output was low in all groups. Although in the previously treated animals faecal egg counts were consistently higher, the differences were minimal, resulting in comparable levels of larval contamination on both paddocks. Serum pepsinogen and antibody levels were not significantly different between the groups and indicated a similar level of larval uptake on both paddocks. No negative effect of the previous chemoprophylaxis on the clinical condition and the weight gain of the second season grazing animals was observed.     

Immunoelectron microscopic evidence for release of eosinophil granule matrix protein onto microfilariae of Onchocerca volvulus in the skin after exposure to amocarzine

The involvement of eosinophils in the host reaction to microfilariae (mf) of Onchocerca volvulus was studied by immunohistochemistry and immunoelectron microscopy. Skin biopsies were obtained from patients after transepidermal administration of the microfilaricide amocarzine. At 20-28 h after the application of amocarzine, mf were degenerated or dead and a marked eosinophil-parasite adherence (EPA) reaction was seen, with intense staining for intra- and extracellular eosinophil granule proteins such as eosinophil cationic protein (ECP) surrounding the mf. Immunoelectron microscopically the eosinophil granule matrix in intact and necrotic eosinophils was specifically labeled, whereas granules whose matrix had dissolved showed no specific gold particle binding. As specific labeling was seen on lowly electron-dense material adjacent to matrix-depleted granules, the material was regarded as released eosinophil granule matrix material. Intact and necrotic eosinophils, matrix-containing as well as matrix-depleted eosinophil granules, and released eosinophil granule matrix material were observed on the surface of damaged mf and between collagen fibers. The coincidence of mf degeneration, EPA reaction, and release of eosinophil granule matrix material on damaged mf and collagen fibers indicated a role of eosinophils and eosinophil granule matrix protein in the host reaction to mf after amocarzine application.     

Effect of intensive treatment on diabetic nephropathy in patients with type I diabetes

We evaluated the long-term effect of an intensive treatment of diabetic nephropathy (anti-hypertensive drugs, low protein diet, multiple insulin injections to achieve a good metabolic control) on glomerular filtration rate (GFR) and albumin excretion rate (AER). Fourteen type I diabetic patients (mean age 45 +/- 9.5 years, mean duration of diabetes 23.5 +/- 7.3 years, 8 males/6 females) with glomerular filtration rate < 70 ml/min-1/1.73 m2 and albumin excretion rate > 30 micrograms/min were treated intensively for 36 months. This intensive treatment consisted of multiple insulin injections, antihypertensive therapy with ACE inhibitors and a low-protein diet (0.8 g/kg body wt/day.) Renal function was evaluated as GFR and AER. HbA1c mean value decreased significantly from 8.7 +/- 0.8% to 6.5 +/- 0.5% (P < 0.0002). GFR rose from 58 +/- 12 ml/min-1/1.73 m2 to 84 +/- 11 ml/min-1/1.73 m2 (P < 0.0008). AER decreased from 208 micrograms/min (range: 73 to 500) to 63.8 micrograms/min (range 15 to 180; P < 0.05). Systolic and diastolic blood pressure decreased respectively from 144 +/- 26 mm Hg to 120 +/- 15 mm Hg and from 89 +/- 9 mm Hg to 75 +/- 8 mm Hg (P < 0.01). We obtained a rise of GFR and a reduction of proteinuria after three years of this treatment. We suggest that this intensive treatment in all patients with early stage diabetic nephropathy may be effective in slowing the progression to renal failure.     

Effect of the treatment with amlodipine on left ventricular hypertrophy in hypertensive patients

BACKGROUND: Left ventricular hypertrophy (LVH) is one of the physiopathological effects of hypertension and one of the main risk factors for sudden death, myocardial infarction and congestive heart failure. Drugs to treat hypertension must not only reduce blood pressure, but also modify the facts which lead to ventricular hypertrophy. This study has been designed to assess the effect of amlodipine, a calcium-antagonist, on LVH in hypertensive patients. METHODS: 20 hypertensive patients (mild to moderate, both sexes, mean age 45.0 yr) were included in a single-blind study. After an initial, four weeks placebo period, active treatment was given (amlodipine 5 mg a day). Dose titration was made after 4-8 weeks to 10 mg a day if necessary and continued until the end of the study. Systolic (SBP) and diastolic blood pressure (DBP), as well as pulse rate (PR) and adverse events were recorded at every visit. Blood and urine analysis, catecholamine, plasmatic renin activity and Mode M echocardiography were made at the beginning and the end of the study. RESULTS: Only one patient was excluded. SBP and DBP showed a significantly fall (p < 0.001). In 80% of patients DBP fell under 90 mm Hg. Every echocardiographic parameter, but left ventricular diastolic dimension, showed significantly reductions at the end of the study: septum thickness (p = 0.001), posterior wall thickness (p = 0.001), left ventricular systolic dimension (p = 0.014), wall relative thickness (p = 0.015), shortening fraction (p = 0.009), left ventricular mass (p = 0.001) and corrected left ventricular mass (p = 0.001). Blood parameters did not modify. CONCLUSIONS: Amlodipine has a beneficial effect on LVH and also is an effective and safe drug to treat mild to moderate hypertension.     

Surgical treatment of paraesophageal hiatal hernia with total intrathoracic volvulus of the stomach

From 1971 to 1993, we operated 44 patients, 34 females and 10 males with a paraoesophageal hernia in which the entire stomach entered the thorax. Mean age of the patients was 70 years. Seventeen patients underwent emergency surgery for strangulated hernia leading to complete ghastric occlusion, gastric bleeding or necrosis (3 cases). Only 2 patients had a past history of gastro-oesophageal reflux. The following techniques were used: abdominal access in all cases, saccular resection, closure of the widened hiatus or of a left sided hernial hiatus, anterior gastropexy suturing the greater curvature to the abdominal on the left. Several patients were in precarious clinical situations and had to be treated under local or regional anaesthesia alone. Two patients had partial necrosis of the stomach and were treated by partial gastropexy. There were no deaths or major complications. Incomplete recurrence was noted in one patient 2 years after the initial procedure. In conclusion: 1) abdominal access is much preferable; 2) an antireflux procedure is only indicated when the patients have signs of gastro-oesophageal reflux; 3) most complications are not due to the hernia itself but to gastric volvulus. Consequently, simple reduction of the hernia followed by anterior gastroplexy under local anaesthesia can give excellent results in patients in precarious clinical situations and argues against major operation with general anaesthesia; 4) due to the gravity of paraesophageal hernia, a surgical solution is required as soon as diagnosis has been confirmed.     

Effects of cognitive load on semantic priming in patients with schizophrenia.

Schizophrenic and control participants received 2 blocks of trials in each experiment. In 1 block they were exposed to regular priming trials (doctor–nurse), and in another block a nonlexical probe was presented at prime onset for 40 ms. Regardless of stimulus onset asynchrony (SOA), the schizophrenic patients showed hyperpriming when no distractor was present. Paying attention to the distracting stimulus reduced priming in the patient group irrespective of SOA. Under certain situations, the reduction in priming appeared even when participants were asked to ignore the distracting stimulus. Thus, even a nonsemantic distractor may be detrimental to schizophrenic patients' language processing. That SOA did not modulate the reduction in priming effect is consistent with the suggestion that attentional resources are required even with short prime–target intervals. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effect of diabetes, insulin, and glucose load on lipid peroxidation in the rat

Lipid peroxidative activity in rats made diabetic with streptozocin and rats made acutely hyperglycemic by intraperitoneal dextrose administration was determined by measurement of exhaled ethane during exposure in vivo to ethane-free air (EFA). Diabetic rats demonstrated increased ethane in the expired breath while breathing EFA (5.82 +/- 0.56 pmol/min/100 g) compared with control rats (4.02 +/- 0.23 pmol/min/100 g). Insulin treatment of diabetic rats attenuated the ethane produced (4.88 +/- 0.23 pmol/min/100 g). Acute hyperglycemia increased exhaled ethane to levels higher than those seen in diabetic rats (9.87 +/- 0.98 pmol/min/100 g). Saline injected intraperitoneally to control rats produced ethane levels similar to those of untreated nondiabetic controls (4.11 +/- 0.52 pmol/min/100 g). Chronic uncontrolled hyperglycemia and acute hyperglycemia are associated with increased in vivo ethane production.