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Biomedical subjects

N Weiss

Publications and source records attributed to N Weiss.

At least 109 records · Page 6Linked to original sources
PubMed1991

Serological evaluation of the macrofilaricidal effects of diethylcarbamazine treatment in bancroftian filariasis.

An Mr 200,000 phosphorylcholine-containing antigen (PC-Ag) of predominantly adult worm origin was found in the sera of humans infected with Wuchereria bancrofti. This paper describes results of a longitudinal study of changes in levels of PC-Ag in response to diethylcarbamazine (DEC) therapy as measured by two-site immunoradiometric assay (IRMA) and Western blotting. One hundred thirty-two residents of a bancroftian filariasis-endemic area of Papua New Guinea (PNG) were treated with a 72 mg/kg dose of DEC. A macrofilaricidal effect was seen with this dose of DEC as 34% of the treated subjects had localized side effects and long-term decreases in microfilariae (mf) counts were observed 12 months after treatment. The PC-Ag levels were reduced to 72%, 52%, and 51% of pretreatment values at 21 days and at six and 12 months after treatment. These decreases, observed by IRMA, were specifically associated with loss of the Mr 200,000 PC-Ag detected by immunoadsorption and Western blotting. From drug treatment data, the maximum half-life of PC-Ag in circulation was calculated to be 50 days, assuming a first-order decay process. This maximum half-life indicates that persistent antigenemia observed in the majority of treated subjects could only result from the survival of adult worms. In the absence of methods to directly demonstrate W. bancrofti adult worms, detection of serum PC-Ag levels provides a sensitive indirect measure of the dynamics of adult worm populations. This serological measurement may be useful in optimizing the macrofilaricidal and therapeutic effects of DEC and in assessing the macrofilaricidal action of new antifilarial drugs and immunological interventions.

Adolescent↗
PubMed1991

Onchocerca volvulus: characterization of monoclonal antibodies reactive with surface components of third-stage larvae.

Five murine monoclonal antibodies (Mab's) have been produced which are reactive with the surface of the third-stage larvae (L3) of Onchocerca volvulus. These were produced from a fusion performed after intrasplenic injection of 10 live O. volvulus L3. Hybridomas were first screened by Elisa using a PBS extract of O. volvulus female adult worms. Elisa negative wells were screened by IFA on whole formalin-fixed L3. Five Mab's were isolated which were reactive with the surface of L3, all were found to be of the IgM isotype. All five Mab's were cross-reactive with the surface of O. lienalis L3, but not with the L3 of Brugia malayi, B. pahangi, Dirofilaria immitis, or Acanthocheilonema viteae. One of the Mab's, OV3-9, reacted with an antigen common to many species of helminths. The other four were genus specific reacting only with O. volvulus and O. lienalis. All 5 Mab's reacted with L2 of O. volvulus, but not with the L4 by IFA on whole fixed larvae. Only Mab's OV3-8 and OV3-9 reacted with cryosections of adult O. volvulus by IFA indicating that the other 3 Mab's are specific for the surface of L2/L3 of the genus Onchocerca. None of the Mab's reacted with detergent dissociated L3 proteins in Western Blot analysis. The ability of L3 to bind the Mab's was abolished by incubating larvae in either proteinase K or trypsin but was unaffected by incubation of larvae in detergents, or by treatment with periodate, indicating the proteinaceous nature of the Mab specific epitopes. Anti-phosphorylcholine Mab (Gib-13) did not react with the surface of L3.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Data-based interventions for cancer control in Texas.

The percentage of excess mortality based on the ratio of the race-ethnic-sex-specific regional rate to the state rate was used to identify regions with differing risks of lung, breast, and cervical cancer. Mortality maps show wide variation in mortality risks for these cancers not only by race and ethnicity but also by geographic region. Cancer-staging information from the State Cancer Registry indicated that excess mortality for breast and cervical cancers in black and Mexican-American women results largely from the later detection of these cancers. Together with geographic mapping of data on cancer mortality, data on the prevalence of tobacco use and on the use of Papanicolaou's tests and mammograms can be used to select and direct interventions to specific regions and to the highest risk populations. Evaluation of routinely collected cancer data, particularly in state health departments, is a primary step in implementing programs to control and prevent cancer in Texas.

Black or African American↗
PubMed1990

[Onchocerciasis in travelers to the tropics].

Two men, aged 54 and 31 years respectively, developed an itching skin rash 18 and 6 months respectively after returning from a trip to Africa, the former also recurrent conjunctivitis. Two years and 6 months, respectively, passed from the time of first symptoms until the diagnosis of onchocerciasis was made. Both patients had an eosinophilia (10.5 and 19%) and specific antibodies against Onchocerca volvulus. Microfilaria were demonstrated in the skin of the younger man. The other one had bilateral corneal infiltrates. Both patients were treated with a single dose of ivermectin, 150 micrograms/kg. Within several months, the clinical symptoms and eosinophilia disappeared and the antibody titres decreased.

Adult↗
PubMed1990

Interaction of monoclonal antibodies with cuticular antigens of filarial parasites, Brugia malayi and Wuchereria bancrofti.

Monoclonal antibodies (mAbs) have been prepared against excretory-secretory-metabolic (ESM) antigens of microfilariae (mf) of Wuchereria bancrofti (WbmfESM) and against third stage larvae (L3) of Brugia malayi (BmL3), and purified from ascites fluids with ammonium sulphate. Both antibodies were of the IgM type and did not react with phosphorycholine. The mAb against BmL3 (F46) reacted in ELISA with antigens of L3 of B. malayi, B. pahangi and W. bancrofti and of adults of B. malayi. The mAb raised against wbmfESM (F32) resembled F46 in this respect, though with a lower titer towards the antigens, and in addition reacted with the ESM-antigens of mf and of L3 of W. bancrofti. F46 was able to detect L3 antigens of filarial parasites in spiked serum samples with a detection limit of 8-16 ng in absolute amount. The antibody was found to label the cuticular portion of L3 and adults of the lymphatic parasites, and not the epicuticular surface, in immunoelectron microscopic studies. The antibody recognized a 36 kDa component of the beta-mercaptoethanol extracts of B. pahangi-adults in Western blot analysis.

Animals↗
PubMed1990

Identification of an Onchocerca volvulus cDNA encoding a low-molecular-weight antigen uniquely recognized by onchocerciasis patient sera.

The primary structure of an immunodominant antigen of the filarial parasite, Onchocerca volvulus was deduced from cDNA sequence analysis. Using affinity-purified antibody from onchocerciasis patients from West Africa, we have isolated a cDNA clone from a lambda gt11 cDNA expression library derived from microfilariae-producing female O. volvulus. The open reading frame encodes 152 amino acids, and the deduced sequence predicts a Mr of 16,850 (consistent with the apparent Mr of 18,000 of the immunoprecipitated in vitro translated product). The primary translation product contains a putative signal peptide of 16 amino acids. The mRNA coding for this antigen has an estimated size of 950 nucleotides. Furthermore, immunoelectron microscopy established that the antigen encoded by this clone is present in the hypodermis, the cuticle, and in the uterus of the filarial worms. Since this antigen is recognized exclusively by sera from onchocerciasis patients, and not by other sera from patients infected by other filarial parasites, it may prove to be an especially valuable tool for improving the specific diagnosis of onchocerciasis.

Amino Acid Sequence↗
PubMed1990

Influence of the shock wave application mode on the growth of A-Mel 3 and SSK2 tumors in vivo.

We examined the influence of different shock wave application modes with a Dornier XL1 electrohydraulic lithotripter on the growth of A-Mel 3 and SSK2 tumors implanted under the dorsal skin of hamsters or mice. In a basic protocol, 500 shock waves a day on 4 consecutive days were administered at a discharge rate of 100 waves per minute and focused to the tumor center. This did not affect A-Mel 3 growth. A similar result was obtained with the basic protocol modified to 1000 shock waves a day and a wave application rate of 100 shock waves per second. Growth of A-Mel 3 and SSK2 tumors was significantly delayed, when the basic protocol was used, but the 500 shock waves a day were distributed over four points at the tumor edges and the tumor center. With the same shock wave protocol, lowering the water level over the tumor from 10 cm to 1 cm induced temporary regressions of SSK2 tumors. This was not due to the higher energy applied to the tumor, since twice the number of shock waves (1000 a day instead of 500 a day) was applied at a high water level and did not induce regressions. Four consecutive treatments with intervals between treatments shortened to 3 h and an additional treatment 12 h later at a low water level completely controlled tumor growth in 8 out of 12 SSK2 tumors for more than 150 days. The result showed that addition of a reflected wave from the water surface was most important for the shock wave effect, and suggested that shock wave devices generating similar wave forms should be applied for tumor therapy.

Animals↗
PubMed1990

Taxonomic study of anaerobic, gram-negative, rod-shaped bacteria from breweries: emended description of Pectinatus cerevisiiphilus and description of Pectinatus frisingensis sp. nov., Selenomonas lacticifex sp. nov., Zymophilus raffinosivorans gen. nov., sp. nov., and Zymophilus paucivorans sp. nov.

A collection of 47 strains of obligately anaerobic, gram-negative, rod-shaped bacteria that were isolated mainly from spoiled beer and pitching yeast was studied to learn more about their taxonomic positions. A new species of the genus Pectinatus, Pectinatus frisingensis, a new species of the genus Selenomonas, Selenomonas lacticifex, and a new genus comprising two species, Zymophilus raffinosivorans and Zymophilus paucivorans, are described. All of the strains contained directly cross-linked meso-diaminopimelic acid-containing peptidoglycan and in addition the diamine cadaverine or (rarely) putrescine. The diamine was covalently linked to the alpha-carboxyl group of D-glutamic acid in the peptide subunit of peptidoglycan. Lipid F was also found as a characteristic cellular compound. The phylogenetic relationships of members of these new species were examined by reverse transcriptase sequencing of 16S rRNA or by DNA-DNA hybridization studies or both. All of the organisms belong to the subdivision containing species with gram-negative cell walls within the phylum of gram-positive bacteria. This finding is in good agreement with the presence of a peptidoglycan that contains diamine.

Anaerobiosis↗
PubMed1990

[Current trends in parasitological diagnosis].

During the past few years a number of modern techniques has found its way into the discipline of diagnostic parasitology. The scale of these new tool ranges from highly sensitive and low toxic fixatives for intestinal protozoa, to rapid detection methods for malarial parasites and to the techniques of modern biology, like hybridoma and DNA technology.

Animals↗
PubMed1990

[Fundamentals of immunodiagnosis exemplified by parasitic infections].

The rapid development in the fields of immunology, biochemistry and biotechnology had a strong impact for immunodiagnosis. The use of monoclonal antibodies, recombinant antigens and synthetic peptides has considerably improved many diagnostic techniques. However, considerations on the meaning of a test result (on the basis of the concept of predictive values) are of prime importance: false use and inappropriate knowledge of the limitations of a technique can lead to diagnostic errors.

Animals↗
PubMed1989

A technique for the treatment of mandibular body fractures in young children.

Mandibular body fractures in young children are uncommon, yet their treatment and management often present several difficulties. The presence of developing dental follicles may lead to irregular fracture lines and precludes the use of intraosseus wiring. In addition, treatment of fractures in children of this age requires a technique that limits the number of separate procedures that they are subjected to. The technique outlined below for the treatment of mandibular body fractures in young children, uses a plastic impression tray as a splint and provides a simple means for their reduction and fixation.

Child↗
PubMed1989

Evaluation of a specific enzyme immunoassay for onchocerciasis using a low molecular weight antigen fraction of Onchocerca volvulus.

A micro-ELISA technique has been developed for the diagnosis of onchocerciasis. With the use of a low molecular weight (LMW) fraction of a soluble, adult Onchocerca volvulus extract as an antigen, the problem of nonspecificity observed with the crude worm extract is negligible. Seventy-three sera from proven cases of other filarial infections were weakly reactive or nonreactive. From cross-sectional and longitudinal surveys in a West African village hyperendemic for onchocerciasis, we concluded that this assay detects antibodies elicited when female worms start to produce microfilariae. Thirty-two of 33 children aged less than or equal to 15 years with positive skin snips were seropositive. High antibody levels could also be found in children who only became parasitologically positive 1-4 years after seroconversion. This leads to the conclusion that serology is more sensitive than the 2-snip method. In individuals with chronic infection (exposed for greater than 15 years), antibody titers were consistently lower (independent of the density of skin microfilariae) than in the early phase of a patent infection. A comparative serological study in a mesoendemic village revealed that the assay can serve to assess onchocerciasis prevalence by testing individuals aged 5-15 years.

Adolescent↗
PubMed1989

Liver disease in rural Tanzania--a diagnostic approach.

In a prospective study on the aetiology of liver disease and its diagnostic approach in a District hospital in rural Tanzania, 48 consecutive patients with evidence of liver disorders were investigated by physical examination, biochemical tests, laparoscopy and histology. Liver cirrhosis (posthepatic, alcoholic) was found in 31%; non cirrhotic alcoholic liver disease in 15%; viral, bacterial and protozoal liver disorders in 33%, and neoplastic liver changes in 21% of all patients. Clinical impression alone coincided with the final diagnosis in 40% of all cases. This figure was increased to 46%, when haematological and biochemical results were included, and to 71%, when laparoscopy (without histology) was used in addition. Laparoscopy was particularly decisive in the diagnosis and further management of cirrhosis, liver abscess and neoplastic liver disorders. The additional information obtained from histology led to the final diagnosis. Histology was specially useful for the diagnosis of alcoholic liver disease, tropical splenomegaly syndrome and non specific reactive hepatitis. The usefulness of laparoscopy as a diagnostic tool in a district hospital is discussed.

Adolescent↗