Exceptional points and asymmetric mode conversion in quasi-guided dual-mode optical waveguides

Non-Hermitian systems host unconventional physical effects that be used to design new optical devices. We study a non-Hermitian system consisting of 1D planar optical waveguides with suitable amount of simultaneous gain and loss. The parameter space contains an exceptional point, which can be accessed by varying the transverse gain and loss profile. When light propagates through the waveguide structure, the output mode is independent of the choice of input mode. This "asymmetric mode conversion" phenomenon can be explained by the swapping of mode identities in the vicinity of the exceptional point, together with the failure of adiabatic evolution in non-Hermitian systems.

Thoracic intramedullary schwannoma: A case report and review of literature

Intramedullary schwannomas are rare spinal cord tumors. Most of these tumors have been reported as a single lesion in the spinal cord. Up until today approximately 50 cases of intramedullary shwannomas not related to neurofibromatosis have been described. We describe a rare case of thoracic intramedullary tumour in a 28 year old male patient who presented with progressive weakness of both the lower limbs and decreased sensation below D2 dermatomal level. Magnetic resonance imaging revealed an intramedullary lesion from D1 toD7. D1 to D7 laminoplasty and near total excision of the mass done. Total removal was difficult because of the infiltrative nature of the tumour. Histopathological report confirmed the diagnosis of the schwannoma. Possible site of origin and pathogenesis of intramedullary tumour have been discussed.

Bobbling head in a young subject

Bobble-head Doll Syndrome is a rare and unique movement disorder found in children. Clinically, it is characterized by a to and fro or side to side movement of the head at the frequency of 2 to 3 Hz. It is mostly associated with cystic lesions around the third ventricle, choroid plexus papilloma, aqueductal stenosis and other rare disorders. An eleven year old child presented in the outpatient department with continuous to and fro movement of the head and declining vision for the last one month. MRI Scan showed a large contrast-enhanced lesion in the region of the third ventricle along with gross hydrocephalus. Ventriculo-peritoneal shunt was inserted and the movements of the head disappeared completely. Bobble-head doll syndrome is a rare condition and therefore this case is presented and the literature reviewed.

Risk factors for cancer of cervix, status of screening and methods for its detection

INTRODUCTION

Cervical cancer is a major health problem of Indian women. It is the second most cancer after breast cancer. In India, every year many women suffer from this cancer because they are illiterate and ignored about cervix cancer severity. As India is a socio-economically backward country of the world, most of the women visiting doctor are from rural areas, they have poor hygienic conditions and many more cervical cancer risk factors.

RESULT

So this review is an attempt to discuss about all of the major risk factors for cervical cancer, screening factors and detection methods for cervical cancer.

CONCLUSION

It aims to keep women of India keeping aside in rural areas informed about cervical cancer severity and its method of detection.

A rare case of Hamartoma of nose and upper lip

Hamartoma though quite common in face and head-neck region, huge size of such a magnitude is not very common- hence the case is being reported.

Evaluation of improvement of hearing in type I tympanoplasty & its influencing factors

study included 40 patients treated for CSOM with central perforation. Only type I tympanoplasty was done in 30 patients with dry central perforation and simple mastoidectomy with type I tympanoplasty was performed in 10 patients with moist or discharging perforation. Type I tympanoplasty utilizing an underlay technique with TFG shows high probability of success (85%). Presence of bilateral perforations lowers the success rate (66.66%). Status of non-operated ear is a significant factor for success rate. An overall hearing gain of about 10db was achieved. Poor pre-operative hearing status of elderly adversely influences post-operative improvement of hearing. Typel tympanoplasty with simple mastoidectomy results excellent surgical success rate (100%) but gives less improvement of hearing (closure of A-B gap= 3.3db). In type I tympanoplasty alone surgical success rate drops to 80-75% but is offers more improvement of hearing (closure of A-B gap = 6.708 db).

Unusual case of coin in larynx (glottic chink) presenting as Dysphagia

Foreign body larynx is a rare condition in adults - inhalation of coin and impaction of the coin in the glottic chink is more rare finding. But this patient presented with difficulty in swallowing and speech, without any respiratory trouble - Hence the case is reported.

Growth retardation due to undiagnosed foreign body oesophagus

Foreign body oesophagus, specially, coin is not very uncommon in children. But an undiagnosed old foreign body (coin) presented with growth retardation and swallowing in a peculiar posture, which has to be removed by thoracotomy-a case report.

Cerebrospinal fluid and serum carcinoembryonic antigen in brain tumors

Carcinoembryonic antigen (CEA) has been indicated to be a marker for brain tumors. In this study CEA was measured in serum and cerebrospinal fluid (CSF) of 14 patients with benign brain lesions, 16 with primary brain tumors and 8 with metastatic brain tumors by radioimmuno assay. Tumor cyst fluid CEA of 6 patients having intracranial tumors was also measured. The control group (n=20) had no neurological disease. The mean CEA levels in CSF for the control group, patients with benign tumors, primary tumors and metastatic tumors were 0.22 ng/ml, 0.31 ng/ml, 0.92 ng/ml, and 6.3 ng/ml respectively. Corresponding serum CEA levels were 2.5, 2.7, 3.0 and 5.2 ng/ml. Results showed that CEA level in CSF may play an important role in differential diagnosis of primary and metastatic brain tumors and consequently management of the treatment. To our knowledge this is the first such study on brain tumors from India.

Reduced expression of the BRCA1 gene and increased chromosomal instability in MCF-7 cell line

Using clonal cell cultures, a significant increase in chromosomal aberrations (aneuplolidy, dicentrics and chromatid breaks) were observed in MCF-7 cells compared with HeLa. BRCA1 expression was lower in MCF-7 cells than in HeLa cells. Since BRCA1 is known to play a role in the maintenance of chromosomal integrity, the increase in chromosomal aberrations in MCF-7 clones suggests that downregulation of BRCA1 expression could be one of the possible mechanisms for increased chromosomal instability in this cell line.

Effect of omega-3 fatty acid (docosahexanoic acid) on BRCA1 gene expression and growth in MCF-7 cell line

Recently, we have demonstrated that omega-6 fatty acid linoleic acid (LA) in presence of estradiol (E2) enhances proliferation and anchorage independent growth with down regulation of BRCA1 mRNA expression in MCF-7 cell line. Since omega-3 fatty acid (docosahexanoic acid, DHA) is known to block the promoting effect of omega-6 polyunsaturated fatty acid (LA), we wanted to see whether addition of DHA can inhibit the growth of MCF-7 cells which are exposed to LA + E2 and any alteration of BRCA1 mRNA expression could be seen in DHA treated culture. Experiments on MCF-7 cells with DHA revealed both decrease in proliferation and anchorage independency as compared to controls; while no change of BRCA1 mRNA expression was observed. Further, when DHA was administered to cells along with LA + E2, no change in BRCA1 expression was observed, however, a marked decrease in proliferation and soft agar colony formation was evident, indicating inhibition of MCF-7 cells following DHA treatment. Flow cytometric analysis showed that DHA treated cells either alone or in combination with LA + E2 induced marked G1/S and G2/M arrest of the cells, suggesting the inhibitory effect of DHA at this phase of cell cycle. However, neither typical DNA ladder nor fragmented nuclei or apoptotic bodies were observed, ruling out presence of apoptosis following DHA treatment.

Implication of BRCA1 gene in breast cancer

Breast cancer susceptibility gene (BRCA1) is known to be responsible for hereditary breast and ovarian cancer. This gene is highly penetrant conferring a risk for 0.92 by the age of 70. Germline mutation in this gene leads to susceptibility to breast and ovarian cancer, with a genotype phenotype correlation. Frequency of mutations of this gene in normal population of breast cancer is low suggesting that the effort of primary screening for BRCA1 gene should be restricted to only familial cases with a strong history of breast and ovarian cancer. Recent studies indicate that BRCA1 is a tumor suppressor gene responsible for both normal development and carcinogenesis of the breast. Normal function elucidated so far, reveal BRCA1 to be a multifunctional protein involved in DNA repair, cell cycle regulation and transcription. There is circumstantial evidence that gene interacts with p53, a protein involved in cell cycle control, DNA repair and apoptosis.

Natural killer cell function and genetic instability in unaffected individuals from breast cancer families

Several recent reports highlight the importance of modifying factors in determining the risk for cancer of a person carrying a mutant allele of a tumour susceptibility gene. The study of two such risk modifying factors namely, natural killer (NK) cell function and constitutional cytogenetic anomalies in members of families with familial breast cancer is presented in this paper. We observed that, compared to healthy controls, a significant proportion of unaffected persons from breast cancer families not only display lower NK cell function or genetic instability alone, but also in conjunction. The significance of these observations is discussed. We propose that amongst the unaffected members, persons with lower NK cell function as well as constitutive cytogenetic anomalies may be at a higher risk for cancer. The need for a set of suitable biomarkers to identify individuals at high risk from familial breast cancer families has been recognized for many years. Constitutional cytogenetic anomalies, otherwise seen in breast tumours, have also been observed in lymphocyte cultures from unaffected persons from such families. Lowered NK cell function has previously been demonstrated in first degree relatives of cancer patients. Both these parameters have been implicated in determining the risk of developing malignancy. In the present study these aspects have been investigated simultaneously in order to assess their utility as potential biomarkers.

Reduced DNA repair capacity in breast cancer patients and unaffected individuals from breast cancer families

It has been suggested that increased fragile site expression in lymphocyte cultures can be used as a marker for genetic predisposition to cancer. We wished to determine whether aphidicolin (APC), an inhibitor of the DNA repair enzyme DNA polymerase alpha, could be used as a reliable biomarker in identification of DNA repair capacity in unaffected individuals at high risk from breast cancer families. PHA-stimulated lymphocyte cultures, with and without APC, were set up in 65 individuals, of whom 14 were breast cancer patients, 26 were unaffected individuals from breast cancer families, and 25 were controls. A significant proportion of breast cancer patients and unaffected individuals from familial breast cancer (FBC) families exhibited premature separation of centromeres (PSC) and aneuploidy in the untreated cultures. In the APC treated cultures, almost all such individuals exhibited a marked depression of mitotic index and increased aneuploidy, as compared to controls. Our results indicate that these individuals have defective DNA repair capacity. Such individuals could thus have a much higher risk of cancer as compared to persons exhibiting PSC and aneuploidy or DNA repair defects alone. We propose that APC may be a valuable biomarker in identifying individuals with genetic predisposition to cancer from FBC families.

Premature separation of centromere and aneuploidy: an indicator of high risk in unaffected individuals from familial breast cancer families?

It is estimated that one in every four women with a first-degree relative affected by breast cancer will develop the disease. Recent evidence suggests that susceptibility to breast cancer can be inherited. We have carried out cytogenetic analysis on PHA-stimulated lymphocyte cultures of breast cancer patients (familial and sporadic), patients with benign breast lesions, unaffected individuals from families with a history of breast cancer and healthy controls. A high incidence of premature separation of centromere (PSC) and aneuploidy was observed in a significant proportion of familial breast cancer patients and patients with fibrocystic disease as well as in some unaffected individuals from breast cancer families. These observations are also supported by cytogenetic analysis of EBV-transformed lymphoblastoid cell lines established from some of these individuals. No such aberrations were detected in the controls. Further, most of the affected and unaffected individuals with these two anomalies also exhibited structural chromosomal aberrations of 1q, 6q, 7q, 16q, 18q, or Xq. Based on these observations, we propose that the presence of both PSC and aneuploidy in lymphocyte cultures of unaffected individuals from breast cancer families can be used as an important predictive parameter to determine the risk of developing cancer.

A simple technique for improving chromosome spreads from clumped metaphases

A method has been described by which clumped metaphases either due to inadequate hypotonic KCl treatment or prolonged storage at 4 degrees C can be rescued. The cell pellet obtained from cell suspension following centrifugation was resuspended in freshly prepared Carnoy's fixative (1:3, acetic acid: methanol) at room temperature by vortexing. Twenty microliters of Triton X-100 at a concentration of 0.5% was added drop by drop while vortexing. Three changes with fixative containing 0.5% Triton X-100 were optimal for obtaining good metaphase spreads with complete removal of the cytoplasmic background. The advantage of this technique is that important patients' samples having clumped metaphases otherwise not useful for G-banding can be rescued and karyotyped by this method.

Implication of involvement of rat chromosome #2 in spontaneous transformation of the rat-2 cell line

Using an in vitro model for cell transformation, the relationship between specific chromosomal aberration and phenotypic changes was studied at different passages of Rat-2 cell line. A marker chromosome resulting from a translocation [t(2;7)] was found to be associated with focus formation in soft agar. Conversely, the loss of this marker chromosome was found to be associated with phenotypic reversion. These results suggest an association of this marker chromosome with phenotypic transformation for the Rat-cell line.

Analysis of computer-predicted antibody inducing epitope on Japanese encephalitis virus

Theoretical methods to delineate antibody inducing epitopes have been employed to predict antigenic determinants on envelope glycoprotein (gpE) of Japanese encephalitis (JE), West Nile (WN) and Dengue (DEN) I-IV viruses. A predicted region on JE virus gpE 74CPTTGEAHNEKRAD87 was synthesized, conjugated to KLH (KLH-peptide) and used in immunization of mice. A mouse monoclonal antibody (MoAb IVB4) reactive to the peptide was also found to react with native JE virus gpE. Characterization of the idiotypic (ID) determinants with the help of polyclonal domain-specific anti-ID antibodies revealed that polyclonal anti-KLH-peptide antibodies and MoAb IVB4 are flavivirus-cross-reactive to Hx and NHx domains, respectively. The region 74-87 in JE virus gpE has been mapped as a linking area between Hx and NHx domains. Reactivity of the peptide with sera from JE patients and vaccinees also indicated the feasibility of using predicted peptides for diagnostic and prophylastic purposes.

Immunofluorescence studies on the replication of some arboviruses in nucleated and enucleated cells

Porcine stable kidney (PS) or Vero cells infected with either flavi-(Japanese encephalitis--JE, West Nile--WN, and Dengue--DEN-2) or alphaviruses (Chikungunya--CHIK and Sindbis--SIN) were stained in indirect fluorescent antibody (FA) assay with anti-JE virus monoclonal (MoAb) Hx-3 (flavivirus cross-reactive) and polyclonal (immune PF) antibodies. By 48 hr post infection (p.i.), 15 to 20% of the three flaviviruses and CHIK virus infected cells, which revealed positive cytoplasmic immunofluorescence (IF), showed intranuclear IF. By 24 hr p.i., the intranuclear IF was not observed or became diminished. The enucleation of cells by cytochalasin B treatment prior to the infection with any of the three flaviviruses resulted in the loss of IF compared with the cells enucleated after the infection (18 hr p.i.) whereas SIN or CHIK virus-infected cells reacted similarly by the either method. These findings indicate an essential role of the nucleus in the replication of the flaviviruses only and while replicating in the infected cells, flaviviruses and CHIK virus might express viral specific proteins in the cell nuclei.

Detection of viral antigens on the surface of cells infected with Japanese encephalitis virus by modified immunofluorescent technique

A modified immunofluorescent method employing anti-Japanese encephalitis (JE) virus monoclonal (MoAbs) and polyclonal (immune PF) antibodies was evaluated for the detection of viral antigens expressed on the surface of porcine stable kidney cells infected with JE virus (733913, India). The infected cells showed granular immunofluorescence on the surface with both the MoAbs, Hs-1 and Hx-3 and immune PF 24 hr and 48 hr post virus infection. Interestingly, two strains of JE virus viz. Yoken (Japan) and 755468 (India) which did not react with the MoAb Hs-1 in the standard indirect fluorescent antibody (FA) technique, were positive for surface immunofluorescence (IF) with the same MoAb. Thus, the modified technique will be useful for the detection of more labile and conformational-dependent epitopes which might get lost or denatured by prior fixation of infected cells with acetone.

Monoclonal antibody to Japanese encephalitis virus cross-reacting with histones present in the cell nuclei

An immunoglobulin G (IgG2b) class of monoclonal antibody (MoAb, NHA-1) raised against Japanese encephalitis virus (JEV) E glycoprotein, reacted with the viral antigen expressed in cytoplasm of the infected cells and also with the cell nuclei, by an indirect fluorescent antibody technique (FA). The NHA-1 reactivity to nuclei was found to be due to its recognizing a JEV cross-reactive epitope present on the nuclear histones. Adsorption with calf thymus histones (type II-AS) showed a drop in NHA-1 reactivity to both JEV and histones by an enzyme-linked immunosorbent assay (ELISA) and indirect FA; the drop was higher against the histones. The MoAb recognized specifically the viral antigens expressed on the infected porcine kidney cell surface by a modified indirect FA. ELISA carried out with glutaraldehyde-fixed antigens showed an almost 2-fold increase in the reactivity over unfixed JEV antigen but none for the histones. Thus, the results indicate that histones share a sequential homology with E glycoprotein of JEV, which might lead to an autoimmune disorder induced due to the molecular mimicry between these two antigens.

Detection of virus specific IgG subclasses in Japanese encephalitis patients

During the Japanese encephalitis (JE) epidemic in 1988 at Gorakhpur, Uttar Pradesh, 34 cerebrospinal fluid (CSF) samples with 16 matching sera from 34 anti JEV IgM positive (confirmed JE) and 24 CSF samples with 4 matching sera from 24 anti JEV IgM negative (clinical encephalitis) patients were collected and tested for presence of JEV specific IgG by ELISA. Eighteen CSF samples and 8 matching sera from confirmed JE and 5 CSF samples and one matching serum from clinical encephalitis patients positive for JEV specific IgG were further assayed for subclass specificity using specific murine monoclonal antibodies. Almost all the samples exhibited IgG1 as the virus specific subclass. In addition to IgG1, one serum and one CSF sample each from two different confirmed JE patients showed the presence of virus specific IgG4 and IgG3 respectively. Half of the confirmed JE and clinical encephalitis patients exhibited intrathecal synthesis as evident from either elevated IgG index or CSF IgG/CSF albumin ratio. Most of the patients who recovered had predominantly virus specific IgG1 in CSF. It seems likely that IgG1 might have a protective role in clearance of virus from the central nervous system.

Circulating interferon-alpha in patients with Kyasanur forest disease

Endogenous interferon (IFN) levels were monitored in acute (51) and convalescent phase (19) sera collected from patients suffering from Kyasanur forest disease (KFD). Levels of circulating IFN in the acute samples (GM 216.3 +/- 8.7) collected between 4 to 7 post onset day (POD) were significantly higher (P less than 0.001) than the convalescent samples (GM 13.19 +/- 1.6) collected between 30th to 90th POD. Interferonemia was concomitant with the viraemic phase. Neutralization studies indicated that the endogenous (circulating) IFN was antigenically similar to acid stable form of IFN-alpha.

Characterization of & induction of immune response to anti-idiotypic antibodies for JE virus

Anti-idiotypic antibodies (anti-Ids, Ab2s) were prepared by immunizing rabbits with two murine monoclonal antibodies (Ab1) having specificities for two independent haemagglutinin (HA) epitopes on JE virus [viz., Hs-1, monoclonal antibody (MAb) specific for Japanese encephalitis virus (JEV) and Hx-1, MAb common to flaviviruses]. Anti-Hs-1 (S-Ab2) and Anti-Hx-1 (X-Ab2) reacted specifically with the immunizing Ab1. In addition, they could react with other MAbs whose reactivity was similar to their immunizing homologous Ab1. The paratope inhibition assay indicated that both anti-idiotypes recognized paratope related idiotopes on their respective Ab1 and could therefore be designated as Ab2 beta. Experimental animals (Swiss mice, Balb/c mice and guineapigs) immunized with S-Ab2 or X-Ab2 produced anti-JE virus antibodies (Ab3) which could be detected by enzyme linked immunosorbent assay, immunofluorescence, haemagglutination inhibition and neutralization tests. The anti-idiotypes were also found to stimulate a cellular immune response in vitro as assessed by 3H thymidine incorporation by lymphocytes from JE vaccinated individuals and experimentally immunized Balb/c mice. The findings of the present study suggest that both the anti-Id antibodies are homobodies which may act as surrogate antigens to manipulate the immune response against JEV.

Nuclear immunofluorescence in porcine kidney cells infected with Japanese encephalitis virus

Acetone-fixed porcine stable kidney (PS) cells infected with Japanese encephalitis (JE) virus were stained in indirect fluorescent antibody (FA) assay with anti-JE virus monoclonal (MoAb) and polyclonal (immune PF) antibodies. First positive immunofluorescence (IF) occurred in the cytoplasm with MoAb Hs-1 (anti-envelope, JE-specific) and immune PF after 7 hr post-infection (p. i.); it became prominent by 15 hr to 48 hr (maximum) when cells reacted strongly also with MoAb Hx-3 (flavivirus crossreactive epitope). In addition, 15 to 20% of the infected cells, which revealed positive cytoplasmic IF, showed intranuclear IF with Hs-1, Hx-3, and immune PF by 20 to 24 hr p.i. By 48 hr, the intranuclear IF was not observed or became diminished. These observations indicate that the JE virus specific epitope Hs-1 appeared first followed by the flavivirus cross-reactive epitope Hx-3. Nuclei of the infected cells seem to play some role in the replication of JE virus.

Recognition of helper T cell epitopes in envelope (E) glycoprotein of Japanese encephalitis, west Nile and Dengue viruses

Helper T (Th) cell antigenic sites were predicted from the primary amino acid sequence (approximately 500 in length) of the envelope (E) glycoprotein (gp) of Japanese encephalitis (JE), West Nile (WN) and Dengue (DEN) I-IV flaviviruses. Prediction of Th epitopes was done by analyzing the occurrence of amphipathic segments, Rothbard-Taylor tetra/pentamer motifs and presence of alpha helix-preferring amino acids. The simultaneous occurrence of all these parameters in segments of E gp were used as criteria for prediction as Th epitopes. Only one cross reactive epitope was predicted in the C-terminal region of the E gp predicted segments of all flaviviruses analyzed. This region is one of the longest amphipathic stretch (approximately from 420 to 455) and also has a fairly large amphipathic score. Based on the predicted findings three selected peptides were synthesized and analyzed for their ability to induce in vitro T cell proliferative response in different inbred strains of mice (Balb/c, C57BL6, C3H/HeJ). Synthetic peptide I and II prepared from C-terminal region gave a cross reactive response to JE, WN and Den-II in Balb/c and C3H/HeJ mice. Synthetic peptide III prepared from N-terminal region gave a proliferative response to DEN-II in Balb/c strain only, indicating differential antigen presentation.

Protective effect of 6-MFA, a fungal interferon inducer against Japanese encephalitis virus in bonnet macaques

6-MFA, an extract from the fungus Aspergillus ochraceus was administered to 8 bonnet macaques. An equal number of monkeys matched for age, sex and weight received placebo and served as controls. Twenty hours after the administration of the 6-MFA/placebo the monkeys were challenged with an Indian strain of Japanese encephalitis virus by the intranasal route. Signs and symptoms of the disease such as fever, tremors, loss of appetite, dehydration, flaccid paraplegia or quadriplegia were pronounced in all the control monkeys, while in the 6-MFA treated group only two developed symptoms. Virus could be isolated from only one of the 6-MFA treated monkeys on day 6, and from four control monkeys; one each from CSF, spinal cord, blood and from both nasal swab and blood of the fourth monkey. The appearance of HI and N antibodies in 6-MFA treated group was either delayed or completely suppressed. The results indicate that 6-MFA is a potential antiviral agent which can be used to reduce the morbidity and mortality in bonnet macaques (Macaca radiata) experimentally infected with Japanese encephalitis virus.

Selection of a neutralization-escape variant strain of Japanese encephalitis virus using monoclonal antibody

An Indian strain of Japanese encephalitis virus (JEV), 733913, a human isolate from Bankura, West Bengal in 1973, with all the functional epitopes designated by a panel of murine monoclonal antibodies (MAbs), was treated with one of the JEV specific HI reactive MAb(Hs-I). This led to selection of a neutralization-escape variant which showed loss of reaction to three different MAbs belonging to the same domain (Hs) and assumed similar characteristics to another JEV strain (755468) also isolated from Bankura in 1975 from mosquitoes. It is possible that selection of such variant might occur in presence of pre-existing JE antibody (Hs-I type) in pigs which are amplifying hosts of JEV. Subsequent dissemination of such variant virus could occur through mosquitoes.

Epitope analysis of strains of Japanese encephalitis virus by monoclonal antibodies

Twenty one strains of Japanese encephalitis (JE) virus, including 16 from India, were compared antigenically on the basis of their reactivity in immunofluorescence (IF), haemagglutination inhibition (HI), ELISA with captured antigen (ECA), and neutralization (N) tests with JE monoclonal antibodies (MAbs). These MAbs represented three domains of distinct epitopes on the envelope protein, designated as Hs-1 to 4 (JE specific in HI), Hx-1 to 5 (flavivirus cross reactive in HI) and NHs-1 to 2 (non-HI JE virus specific). Fifteen of the 21 strains studied were placed in group I. These reacted with MAbs representing the three domains in all the tests indicating presence of the three types of epitopes with full functional activity. The remaining six strains were placed in group II and showed loss in HI reactivity with Hs MAbs but not with Hx MAbs. All the group II strains also reacted in IF and ECA with NHs-1. Hs epitopes in three strains, G9473 (Tamil Nadu), 641686 (Tamil Nadu) and 822199 (Karnataka), appeared to have mutated partially, indicating loss in HI reactivity with Hs MAbs only, while there was retention of other reactivities, viz., IF, ECA and to some extent N test with G9473 and 641686. The remaining three strains, 691004 (Sri Lankan), 755468 (West Bengal) and Yoken (Japan) of group II showed almost complete loss of Hs-1 and Hs-2 epitopes as there was absence of reactivity in IF, ECA and N test in addition to HI. However, Hs-3 MAb showed reactivity in IF with these strains.(ABSTRACT TRUNCATED AT 250 WORDS)

Route-related variation in the immunogenicity of killed Salmonella enteritidis vaccine: role of antigen presenting cells

In order to assess the role of the route of immunization on the immunogenicity of killed Salmonella vaccine, mice were immunized with killed S. enteritidis by intraperitoneal (i.p.) and intradermal (i.d.) routes. Whereas the former was non-immunogenic, the i.d. immunization generated an excellent delayed-type hypersensitivity response; further, i.p. immunization could even suppress the subsequent i.d. immunization. Since the peritoneal macrophages (MO) are known to be particularly low in Ia or MHC-class II antigens, so essential for antigen presentation, the non-immunogenicity by i.p. route was thought to be due to their poor presentation efficiency. Poly I: poly C, an interferon inducer, is known to enhance the MHC-class II expression; hence effect of poly I: poly C treatment on the immunogenicity of the killed vaccine by i.p. route was tested and indeed the non-immunogenicity was corrected. Poor efficiency of presentation of S. enteritidis antigen by peritoneal cells and its improvement by prior poly I: poly C treatment was further confirmed by in vitro lymphocyte transformation test using primed T cells and peritoneal cells from normal and poly I: poly C treated mice. Poly I: poly C treatment also enhanced expression of Ia antigens on peritoneal cells.

Interferon producing capacity (IPCA) of peripheral mononuclear cell in oral cancer patients

Interferon producing capacity (IPCA) of peripheral blood mononuclear cells is ability of these cells to produce IFN with suitable IFN inducer. In Vitro IPCA of cryopreserved mononuclear cells (MNC) from peripheral blood of 46 oral cancer patients was studied and was compared to that of healthy, age matched donors. New castle disease virus (NDV) and staphylococcal enterotoxin A (SEA) were used as inducers for evaluating Type alpha IPCA (AIPCA) and Type gamma IPCA (GIPCA) respectively. Age of healthy donors did not influence the AIPCA or GIPCA. Oral cancer patients demonstrated significant low AIPCA (P less than 0.05) (Range Healthy donors 3.5 to 4.6 log 10Iu/ml Oral Cancer 2.0 to 4.6 log 10Iu/ml GIPCA was found to be further depressed (P less than 0.005) (Range Healthy donors 2.87 to 3.6 Log 10 U/ml, Oral cancer 1.7 to 3.6 log 10 U/ml. The depression in IPCA was found to be more pronounced in advanced stage of disease.

Epitope mapping of Japanese encephalitis virus envelope protein using monoclonal antibodies against an Indian strain

A panel of monoclonal antibodies (MAbs) raised against an Indian strain of Japanese encephalitis (JE) virus was used to map topographically the epitopes on the envelope protein. Two separate clusters of epitopes were revealed. On the basis of reactivity in haemagglutination inhibition (HI), neutralization (NT), passive protection and antibody-dependent plaque enhancement (ADPE) assays with the MAbs, five functional domains (A, B, C, D and E) were delineated. The flavivirus cross-reactive domain for HI (A) was distinct. The JE virus-specific domain for HI (B) was in continuum with those domains representing non-HI JE virus-specific MAbs (C) and flavivirus cross-reactive MAbs (D). Domain E, which mapped close to domain D was represented by two MAbs that reacted with both JE virus and uninfected cell nuclei. Four conclusions can be drawn. (i) Two distinct antigenic domains were associated with HI, (ii) HI and NT in vivo and in vitro were dissociated functions, (iii) ADPE activity was solely linked with the A domain and (iv) all MAbs reacting with epitopes in the B domain had HI/NT/protective activity but failed to show ADPE. The B domain might therefore be considered the most suitable for development of synthetic or genetically engineered vaccines.

Replication of Japanese encephalitis virus in monkey, pig and chick leucocyte cultures

Japanese encephalitis (JE) virus replicated in monkey, pig and day-old chick leucocyte cultures. The titres obtained on days 3 to 5 after infection in monkey, pig and chick leucocyte cultures were comparable. Treatment of monkey leucocyte cultures with the mitogens phytohaemagglutinin P, pokeweed mitogen (PWM), formalinized Staphylococcus aureus (Cowan I) or concanavalin A and pig leucocytes with PWM did not significantly affect their ability to support replication of JE virus. No relationship was observed between the amount of [3H]thymidine incorporated in untreated or mitogen treated monkey or pig leucocyte cultures and the titres of JE virus in such cultures. The ability of monkey, pig and chick leucocyte cultures to support JE virus replication was abrogated following silica treatment. These findings suggest that monocytes may serve as one of the important sites of JE virus replication.

Regulation of cell-mediated immunity in mice immunised with Salmonella enteritidis

The effects of diverse factors, such as route of immunisation, composition of immunogen and administration of interferon inducer, on the expression of cell-mediated immune responses against Salmonella enteritidis were investigated in BALB/c and Swiss white mice. Immunisation with live cells of S. enteritidis by the intraperitoneal route (ip) generated both delayed type hypersensitivity (DTH) and protective cell-mediated immunity (CMI). However, the two responses showed diametrically opposite time kinetics. The decline and disappearance by 9 weeks after ip immunisation of DTH and the rise of protective immunity in the same period suggested the possibility that the two responses were mediated by different subsets of T cells. Immunisation by the intradermal (id) route with a sonicate of S. enteritidis generated only DTH; id immunisation also suppressed the development of the protective response following ip immunisation with live S. enteritidis. Both responses were not seen when T cells were eliminated with anti-T cell serum. Oral immunisation with live cells of S. enteritidis induced excellent CMI expressing both DTH and protective responses. On the other hand, oral immunisation with the sonicate of S. enteritidis not only did not induce CMI, but also prevented the development of the DTH and protective response to ip immunisation with live S. enteritidis. Induction of interferon by the administration of poly I: poly C for four consecutive days after id immunisation with killed S. enteritidis suppressed the generation of DTH.

Expression of tumor cell properties in synovial cells in culture

The tumorigenic properties of human rheumatoid arthritis synovial cells in culture were investigated. The synovial cells developed good colonies and secreted plasminogen activator (PA) and collagenase in the cell cultures, as do Hela cells. Since PA and progesterone receptor (PgR) are considered to be end products of estradiol action in breast cancer cells, the estrogen receptor (ER) and PgR content in these cells was also assayed. Large amounts of ER and PgR were detected in the synovial cells in culture, even though these cells are not targets for sex steroids. Study of the cytomorphologic changes in the synovial cells in culture revealed many characteristics generally observed in neoplastic cells. Whether any or all of these observations have any implication in prognosis or therapy in this disease remains to be studied.