Awareness about a national immunization day programme in the Sunsari district of Nepal

The initiative to eradicate poliomyelitis globally by the year 2000 was launched at the Forty-first World Health Assembly in May 1988, when all WHO Member States were challenged to help eradicate poliomyelitis from the world, a gift to the children of the twenty-first century. In Nepal, 100-250 children per year become disabled due to poliomyelitis. The government of Nepal is determined to eradicate the disease from the country by the year 2000 through the National Immunization Day (NID) Programme. Since 1996, about 3.3 million children under 5 years of age have been immunized each year in Nepal. In the present study, we analysed the impact of the campaign in the Sunsari district of Nepal. The study was carried out during the first NID (6 December 1996) to evaluate the local population's awareness of the programme and the impact of the media on such awareness. A total of 843 respondents were interviewed, 39% of whom were illiterate. Two important aspects of the mass campaign (whether a child previously immunized should be immunized again in the NID, and whether children should be brought to the next NID) were clearly understood by the majority of the people (93.1% and 98.8% of the respondents, respectively), although only a small proportion (24.4%) of individuals understood the purpose of the programme. Radio was the single most effective means of providing information, education, and communication about NIDs. The encouraging response, especially from a poor, illiterate rural population, augurs well for the goal of eradicating poliomyelitis from the world.

In vivo crushing of an aortic stent enables endovascular repair of a large infrarenal aortic pseudoaneurysm

PURPOSE

To report an unusual approach to endovascular exclusion of a large aortic pseudoaneurysm.

METHODS AND RESULTS

A 63-year-old male had an unsuccessful endovascular repair of an aortic anastomotic pseudoaneurysm that left an expanded, uncovered Palmaz stent lying obliquely within the aorta. After nearly 3 years, the pseudoaneurysm enlarged to 7 cm, and the patient became symptomatic. Repair of the pseudoaneurysm was accomplished by crushing the indwelling stent to allow placement of a stent-graft.

CONCLUSIONS

Malpositioned stents that are hindering an endoluminal procedure may be crushed against the arterial wall in vivo to facilitate passage of endovascular instruments or devices.

Coexpression of mRNA for the full-length neurotrophin receptor trk-C and trk-A in favourable neuroblastoma

Neuroblastoma, a childhood tumour of the sympathetic nervous system, may sometimes regress spontaneously in infants, or progress to a poor clinical outcome despite intensive therapy. Neuroblastomas express neurotrophin receptors and high levels of mRNA for trk-A correlates with favourable outcome, whereas trk-B mRNA is expressed by more unfavourable tumours. Using a sensitive RNase protection assay, mRNA expression for the neurotrophin receptor trk-C was investigated in 50 tumour samples from 45 children at different stages including metastatic and relapsing tumour tissue, out of which 22 were also investigated for trk-A mRNA. Thirty-seven of 43 primary tumours (86%) showed trk-C mRNA with more than 300-fold difference between the highest and the lowest values. A higher trk-C index (trk-C mRNA/GAPDH mRNA) was associated with favourable features such as younger age (P = 0.009-0.003), favourable tumour stage (1, 2 or 4S; P < 0.001) and favourable prognosis (P = 0.044). Better survival probability was shown in children with intermediate or high trk-C index compared with patients with low or undetectable levels (P = 0.031). All localised tumours co-expressed mRNA for trk-A and trk-C receptors. RT-PCR analysis detected mRNA encoding the cytoplasmic trk-C tyrosine kinase region only in favourable neuroblastomas. We conclude that favourable neuroblastoma may express the full-length trk-C receptor while unfavourable tumours, especially those with MYCN amplification, seem to either express no trk-C or truncated trk-C receptors with unknown biological function. Trk-C and possibly its preferred ligand NT-3 may be involved in the biology of favourable neuroblastomas showing apoptosis or differentiation.

Expression of mRNA for the neurotrophin receptor trkC in neuroblastomas with favourable tumour stage and good prognosis

Childhood neuroblastoma tumours of the sympathetic nervous system show a remarkable clinical heterogeneity ranging from spontaneous regression to unfavourable outcome despite intensive therapy. Favourable neuroblastomas often express high levels of trkA mRNA, encoding the tyrosine kinase receptor for nerve growth factor. We have investigated mRNA expression for the neurotrophin receptor trkC in 23 primary neuroblastomas using a sensitive RNAase protection assay. TrkC expression was detected in 19 of these tumours at highly variable levels with a 300-fold difference between the highest and lowest values. Significantly higher levels of trkC mRNA were found in tumours from patients with favourable features such as low age (P < 0.012), favourable tumour stage (P < 0.012) and favourable prognosis (P < 0.05). Children with intermediate or high trkC mRNA expression had better prognosis compared with those with low or undetectable levels (83.3% vs 20%, P = 0.005). Further characterisation of trkC mRNA expression by reverse transcriptase-polymerase chain reaction (RT-PCR) showed that mRNA encoding the full-length cytoplasmic tyrosine kinase domain of the receptor was only expressed in a subset of favourable tumours. These data show that favourable neuroblastomas may express the full trkC receptor while advanced tumours, in particular MYCN-amplified neuroblastoma, seem to either express no trkC or truncated trkC receptors of as yet unknown biological function. These data are suggestive of a role for trkC and its preferred ligand neutotrophin-3, NT-3, in neuroblastoma differentiation and/or regression.

Identification of a 148-kDa surface lectin from Giardia lamblia with specificity for alpha-methyl-D-mannoside

A lectin specific for alpha-methyl-D-mannoside was purified from the membrane extract of Giardia lamblia by a combination of gel filtration chromatography on Sephadex G-75 and Superose 6-HR 10/30. The homogeneity of the lectin was established by sodium dodecyl sulfate polyacrylamide gel electrophoresis. The molecular mass of the native protein was 148 kDa. The lectin agglutinated rabbit erythrocytes in the presence of Ca2+ at 37 degrees C and pH 7.0. The maximum activity of the lectin was obtained after trypsin treatment. The inhibition study clearly suggests that the binding site of the lectin recognizes alpha-methyl-D-mannoside as the immunodominant sugar.

Feasibility of exercise stress echocardiography for the follow-up of children with coronary involvement secondary to Kawasaki disease

BACKGROUND

The development of coronary aneurysms as sequelae of Kawasaki disease can result in myocardial ischemia, infarction, and sudden death. Traditionally, these patients have undergone coronary angiography and nuclear stress imaging for risk stratification and follow-up. However, angiography is invasive, and both modalities expose the patient to repeated radiation, which is an important issue in children. The purpose of this study was to determine the feasibility of performing exercise stress echocardiography in children diagnosed with coronary abnormalities secondary to Kawasaki disease.

METHODS AND RESULTS

Treadmill exercise stress echocardiographic studies were performed in 28 children ages 6 to 16 years. All had acute Kawasaki disease 1 to 10 years before study, and coronary artery abnormalities were identified during previous echocardiographic imaging. Patients were exercised using a standard Bruce protocol. Transthoracic echocardiographic images, obtained in the parasternal long, short, apical two- and four-chamber views immediately before and after exercise, were digitized for review and analysis. In baseline studies before exercise, wall motion abnormalities were identified in 2 patients; these segments became normal with exercise. Two patients developed new exercise-induced wall motion abnormalities that corresponded to angiographically defined critical stenosis of the left anterior descending coronary artery. No patients had resting or exercise-induced ECG evidence of ischemia. There were no adverse reactions, and 26 of 28 patients had normal exercise tolerance.

CONCLUSIONS

Among patients with coronary artery involvement resulting from Kawasaki disease, exercise stress echocardiography is a safe, noninvasive procedure and may identify children with myocardial ischemia that was not detected with ECG stress test alone.

Stimulation of macrophage oxygen free radical production and lymphocyte blastogenic response by immunization with porins

Porins were prepared from smooth strain of Salmonella typhi 0-901 and chemotype rough mutant of S. typhimurium Ra-30. Porins could significantly stimulate the immune systems of mice. Immunization of mice with the porins provoked synthesis of anti-porin antibodies. Macrophages from the immunized mice showed increased capacity to generate oxygen free radicals, and lymphocytes from these mice showed proliferative response to the porins. Thus porins may play a role in providing protection from salmonellosis by stimulating the antibody production and increasing the capacity of macrophages to generate oxygen free radicals along with stimulation of lymphocytes.

Evaluation of Salmonella porins as a broad spectrum vaccine candidate

Porins were prepared from smooth strain of Salmonella typhi 0-901 and chemotype of rough mutant of S. typhimurium Ra-30. Mice were immunized with both the porin preparations in different groups and challenged with S. typhimurium LT2-71 and S. enteritidis SH-1269. Porin immunized mice showed significant protection (P < 0.01) against challenge with homologous as well as heterologous strains. Hence, the use of porins may be attempted in future to protect against salmonellosis.

A cholera-coli related enterotoxin production by different Shigella species

A cholera-coli related enterotoxin production was studied in 50 different Shigella isolates from cases of childhood diarrhoea. Four out of 6 Sh. dysenteriae, 18/37 Sh. flexneri and 2/4 Sh. sonnei were found to be enterotoxin producers by RIL test. All strong RIL positive strains were isolated from cases of severe diarrhoea, indicating the association of enterotoxin production and severity of acute diarrhoea. Two major protein bands were observed in SDS-PAGE and W.B. EIA assay in all positive RIL extracts. These immuno-reactive bands were at 31 kDa and 14 kDa positions resembling A-B subunit structure of cholera-coli family of enterotoxins.

Macrophage-mediated enterocyte damage in BALB/c mice infected with different strains of Giardia lamblia

The mechanism of mucosal injury in Giardia lamblia-infected animals and humans is not well understood, although the role of gut macrophages in killing the trophozoites is well known. It is speculated, however, that macrophage products have a role in tissue injury and inflammatory response during infection, as in other inflammatory diseases. Therefore, in the present study an attempt was made to examine the mechanism involved in enterocyte damage during giardiasis. This was achieved using co-culture of enterocytes and gut macrophages obtained from infected BALB/c mice. The extent of tissue damage was assessed by measuring the marker enzyme of enterocyte damage, lactate dehydrogenase. To investigate the role of the various proteases and free oxygen radicals released by activated macrophages on enterocyte damage, inhibitors of various proteases and free oxygen radicals were used. Superoxide radical and certain proteases were found to have important roles in bringing about enterocyte damage during this infection in mice. Parasite load, lactate dehydrogenase release, and extent of lipid peroxidation were more pronounced in mice infected with symptomatic strains than in asymptomatic ones. The theory of inflammatory cell-mediated enterocyte damage in Giardia lamblia infection is proposed.

Use of hepatitis B vaccine alone or in combination with hepatitis B immunoglobulin for immunoprophylaxis of perinatal hepatitis B infection

The efficacy of hepatitis B vaccine alone or in combination with immunoglobulin in neonates born to HBsAG positive mothers was investigated. Twenty-four infants were given three doses (at 0, 1, 2 months) of the vaccine alone, while 27 infants were given hepatitis B immunoglobulin (HBIG) and three doses of the vaccine. Fifty-eight infants born to HBsAg positive mothers who did not agree for vaccination or could not come for follow-up constituted the control group. The overall seroprotection rates (anti-HBS levels > or = 10 IU/l) were almost similar in both the groups at 6 months (81 and 76 per cent, respectively). However, the seroprotection rates in babies born to HBeAg positive mothers were better with combination of HBIG and vaccine (71 v. 57 per cent, respectively). It was also observed that seroprotection rates in babies born to anti-HBe positive mothers were even better (100 and 90 per cent in vaccine alone and combination group, respectively). No chronic carrier was detected in babies born to anti-HBe positive mothers.

Hepatitis B vaccine alone or in combination with anti-HBs immunoglobulin in the perinatal prophylaxis of babies born to HBsAg carrier mothers

The efficacy of hepatitis B virus (HBV) vaccine alone (group I) or in combination with hepatitis B immunoglobulin (HBIG) (group II) for prevention of perinatal transmission of the virus was assessed in 21 and 24 neonates, respectively. 58 infants who could not be vaccinated constituted the control group. It was observed that in the unvaccinated group approximately 70% of the infants became infected. In both the vaccinated groups, the seroconversion and seroprotection rates (anti-HBs > or = 10 IU/1) were almost similar at 6 months of follow up, but, at 12 months, infants given HBIG and vaccine showed better seroprotection rate (85%) than those given vaccine alone (58.8%). Immune response to the vaccine was also better in both the groups if the mothers were anti-HBe positive. Despite immunization, 14.2% and 25% infants in group I and II, respectively, became chronic carriers if their mothers were HBeAG positive.

An experimental model of ameboma in guinea pig

Among the wide variety of clinicopathological manifestations of intestinal amebiasis, amebomas occur rarely and their pathogenesis is not well understood. When cholesterol-fed, 2- to 4-week-old guinea pigs were infected intracecally with a virulent, monoaxenic strain of Entamoeba histolytica, gross and histologically characteristic amebomas developed in 85% of the animals by the 3rd day, in 94% by the 9th day, and in 96% by the 12th day postinfection, by which time most of them had died. Amebomas were confirmed by histopathology. Thus, a model of consistent production of amebomas was documented.

ELISA for detection of heat stable enterotoxin producing Escherichia coli strains

Among 557 strains of Esch. coli isolated from patients with acute diarrhoea, 392 (70.4%) isolates demonstrated ST production by ELISA. Predominant ST producing serogroups were 020 (45), 078 (40), 0128 (21), 061 (19), 0149 (9), 04, 055, 0106 and 0114 (8 each). The inhibition ELISA range was between 10.5 and 40.5 per cent. Visual difference between a negative and a positive ELISA test was distinct. A comparison of ELISA with classical suckling mouse assay for 100 strains showed 88 and 80 positive strains respectively for ST. ELISA proved a more specific, rapid and sensitive assay which may be useful for screening large number of isolates in epidemiological studies.

Epidemiological study of parasitic infestations in lower socio-economic group in Chandigarh (north India)

When stool samples from 970 subjects belonging to lower socio-economic groups were examined for parasites, a total of 121 subjects (12.5%) i.e., 57 (12.1%) males and 64 (12.9%) females showed positive results. The overall prevalence of parasitic infestation did not correlate with sex, caste or religion and living conditions. However, the prevalence was higher in hospital employees residing in well sanitated area. Giardia lamblia (69.5%), Entamoeba, histolytica (15.7%), Hymenolepis nana (12.4%), Ancylostoma duodenale (10.7%), Ascaris lumbricoides (8.3%) and Taenia (0.8%) were the parasites seen. Mixed infections were seen in 9 subjects. Twenty families of the 196 studied had more than one family member positive for parasites. Asymptomatic positivity was high amongst all groups of subjects, and with all parasites.

A cadherin-like protein in eggs and cleaving embryos of Xenopus laevis is expressed in oocytes in response to progesterone

A new cadherin-like protein (CLP) was identified in oocytes, eggs, and cleavage stage embryos of Xenopus laevis. As a probe for detecting new cadherin proteins, an antiserum was raised to a 17 amino acid peptide derived from a highly conserved region in the cytoplasmic domain of all cadherins which have been sequenced to date. This antipeptide antibody recognized Xenopus E-cadherin and a polypeptide in Xenopus brain extracts similar to N-cadherin, which were independently identified by specific mAbs. In extracts of eggs and midblastula stage embryos the antipeptide antibody recognized specifically a 120-kD glycoprotein that migrated faster on SDS gels than the 140-kD E- and N-cadherin polypeptides. This 120-kD polypeptide was not recognized by the mAbs specific to E- and N-cadherin. In fact, E- and N-cadherin were not detectable in eggs or midblastula stage embryos. The possible relationship of CLP to P-cadherin, which has been identified in mouse tissues, has not yet been determined. CLP was synthesized by large, late stage oocytes. When oocytes were induced to mature in vitro with progesterone it accumulated to the same level found in normally laid eggs. It did not accumulate further to any significant extent during the early cleavage stages. CLP was detected on the surface of stage 8 blastomeres by cell surface biotinylation, but only after the tight junctions of the blastula epithelium were opened by removal of Ca2+. We conclude that CLP is a maternally encoded protein that is the major, if not only, cadherin-related protein present in the earliest stages of Xenopus development, and we propose that it may play a role in the Ca2(+)-dependent adhesion and junction formation between cleavage stage blastomeres.

Enzyme immunoassay (ELISA) for the detection of anticarbohydrate antibodies in rheumatic fever and rheumatic heart disease

Antibodies to group A streptococcal polysaccharide were estimated in the following groups of patients: (I) Patients with uncomplicated streptococcal pharyngitis: 10 patients, followed up for 3 months. (II) Patients with acute rheumatic fever: 8 patients with first attack followed up for one year. (III) Patients with reactivated rheumatic heart disease: 10 patients, followed up for one year. (IV) Patients with chronic rheumatic heart disease: followed up for one year. (V) normal controls without any history of sore throat/fever/vaccination/rheumatic disease: 10 patients followed up for one year. Group (I) patients did not show any significant elevation in anticarbohydrate antibodies by both ELISA and RIA. In the case of (III) and (IV), antibody levels were significantly higher as compared to group (V) and remained so till one year of follow up. In group (II) patients there was no significant rise in antibody levels. There was a good correlation between the ELISA and RIA used to detect the antibody levels. These findings suggest that the use of ELISA to detect anticarbohydrate antibody can be of help in diagnosing cases of rheumatic heart disease (both acute and chronic RHD).

Specific immunoglobulin response in mice immunized with porins and challenged with Salmonella typhi

Specific antiporin antibody (IgG, IgM, and IgA) response was studied in control, infected, immunized-infected, and immunized mice. The activity of specific IgG immunoglobulins was found to be the highest in immunized and immunized-infected groups in which 87.5% protection had been observed by laboratory potency test in mice; the next-highest activities were those of IgM and IgA immunoglobulins. However, in the infected group the activity of specific IgM and IgG immunoglobulins was almost similar.

Cryptosporidiosis and related diseases

Cryptosporidium, is a parasite classified as a member of the class Sporozoea and Subclass Coccidia. The other parasites which are grouped under the Coccidia Subclass are Isospora, Sarcocystis, Plasmodium, Piroplasmia and Microspora. Cryptosporidium, Isospora, Sarocystis and recently some of the Microspora have been observed to cause infections of the gastrointestinal tract. This review summarizes the recent developments in our knowledge about these parasites especially those which are of medical importance.

Humoral and cell mediated immune responses to porins of Salmonella typhi

Humoral and cell mediated immune responses were studied in control, infected and immunized-infected mice at different time intervals. The levels of antiporin antibodies were found to be higher throughout the study period in immunized-infected group in which 87.5% protection was observed by mouse potency test. A significant increase in stimulation index of lymphocyte blast transformation as well as delayed type hypersensitivity response was observed in the same group as compared to infected and control group when porins were used as antigens. Using nonspecific mitogens like PHA and Con A the lymphocyte proliferation was maximum in control group whereas a significant depression was observed in infected mice. It is indicated from this study that porins are excellent antigens interacting efficiently with both arms of the host immune systems which could play a role in providing protection against the disease.

Dot enzyme linked immunosorbent assay for immunodiagnosis of amoebiasis

Dot-enzyme linked immunosorbent assay (Dot-ELISA) used for the serodiagnosis of both intestinal and extraintestinal amoebiasis, showed positivity in 94 per cent patients of amoebic liver abscess and 87.5 per cent of intestinal amoebiasis. Only one of the 18 normal controls was positive by Dot-ELISA test. This test showed good correlation with indirect haemagglutination test. As it is simple and easy to perform, the test appears to have great potential for the specific diagnosis of amoebiasis in peripheral hospitals and also at the field level where sophisticated immunodiagnostic facilities are not available.

Mechanism of innate immunity to amoebic infection in guineapigs

The direct lymphocyte cytotoxicity and antibody dependent cell mediated cytotoxicity against Entamoeba histolytica was studied in 3-4 wk old and 8-10 wk old guineapigs. Both these parameters were significantly increased in splenic cells in the older animals. This might be due to maturation of the immune system or to natural infection by related parasite, leading to immunity.

Cryptosporidium causing chronic diarrhea

The authors report a case of a child with chronic diarrhea due to Cryptosporidium. The child had also hemolytic uraemic syndrome. Cryptosporidium oocysts were identified by the modified Ziehl-Neelsen technique.

Role of immune complexes in cerebral malaria

To investigate the involvement of immune complexes in the pathogenesis of cerebral malaria, a comparative study between Plasmodium berghei infected Swiss albino mice and BALB/c mice was conducted. Rise in parasitemia was found to be same with differences in manifestation of disease and mortality, level of immune complexes and histopathology. Increased parasitized red cells with swelling of endothelial cells in the brain capillaries along with increased levels of circulating immune complexes were observed in the BALB/c mice.

Enzyme-linked immunosorbent assay using excretory/secretory and somatic antigens as a diagnostic test for human hookworm infection

Excretory/secretory (E/S) and somatic antigens prepared from third stage infective larvae of Ancylostoma duodenale were evaluated for the diagnosis of human hookworm infection by enzyme-linked immunosorbent assay (ELISA). Taking the mean absorbance plus 2 standard deviations (SD) of normal serum as the cut-off value, the positivity rates in 30 hookworm cases were 97% and 93% respectively. False positivity with E/S antigen was 8-20% in 61 control subjects; with somatic antigen it was slightly lower. In contrast, when the mean absorbance value plus 2 SD of control groups with other parasitic infections was taken as cut-off point, the positivity was 93% with E/S antigen and 43% with somatic antigen, indicating the superiority of E/S antigen. Percentage positivity declined after treatment of hookworm cases. No relationship was found between ELISA reactivity and severity of infection.