Immune responses in normal Indian langur monkeys (Presbytis entellus)--a primate model for visceral leishmaniasis

The Indian langur monkey (Presbytis entellus) is an experimental host for a range of human diseases and for the assessment of vaccine candidate antigens to some common parasitic infections. This experimental host is particularly suitable for the follow-up of immunological responses. To understand some of the mechanism that underlies the defense against experimental pathogens there is a need of the basic knowledge on antibody and cell mediated immune responses. In the present study 25 naïve monkeys were subjected to for assessment of their antibody responses to various human parasitic antigens as well as mitogen induced cellular responses. Only few monkeys were found to have low titer of antiparasitic antibodies. There was compressive dose dependent proliferative response of peripheral blood mononuclear cells. Unlike humans, the blastogenic as well as cytokine responses (IFN-gamma, IL-2 and IL-4) to Con A was considerably higher as compared to PHA. These findings are similar to what have been reported in other non-human primates, confirming the appropriateness of Indian langurs for pre-clinical trials.

A serological study of intrafamilial spread from patients with sporadic hepatitis E virus infection

Intrafamilial transmission is rare in epidemic hepatitis E; its frequency in sporadic hepatitis E is not known. We followed up 86 household contacts (age range 4-75 years, mean +/- SD 32.4 +/- 15.8; 49 males), who were family members of patients with acute sporadic hepatitis E. Of the 86 contacts, 68 (79%) tested negative for IgG anti-hepatitis E virus antibodies. Four (4.7%) had IgM anti-hepatitis E virus antibodies at the time of diagnosis of hepatitis E in the index case; two of these contacts possibly had hepatitis E virus infection acquired simultaneously with that in the index case, and two could have had intrafamilial transmission. None developed serological evidence of hepatitis E virus infection over a period of 49 +/- 18 days after the diagnosis of index case, although a majority lacked IgG antibodies to hepatitis E virus and were likely to be susceptible. This suggests that person-to-person transmission is uncommon in sporadic hepatitis E.

Prophylactic potential of autoclaved Leishmania donovani with BCG against experimental visceral leishmaniasis

The prophylactic efficacy of autoclaved Leishmania donovani (ALD) and autoclaved L. major (ALM)--a heterologous vaccine developed against cutaneous leishmaniasis (used as a reference vaccine), along with BCG--was evaluated against L. donovani in hamsters (Mesocricetus auratus). Animals were immunized with triple doses (21 days apart) of either ALD or ALM (1.0 mg) with or without BCG (0.1 mg) and challenged 21 days later with 1 x 10(6) L. donovani amastigotes intracardially. Animals immunized with ALM + BCG and ALD + BCG yielded 94.3% and 86.1% parasite inhibition respectively in comparison to the BCG only and unvaccinated controls. Fifty and 33.3% of the vaccinated animals (ALM + BCG and ALD + BCG respectively) were completely devoid of parasites when tested on day 45 post-challenge (p.c.) and survived till the experiment was terminated. The mean survival of ALM + BCG and ALD + BCG groups (animals harbouring parasites) was longest (168 and 139 days respectively). No significant increase in anti-leishmanial antibody level (ELISA) was noticed in ALD + BCG and ALM + BCG groups whereas it increased progressively in the rest of the experimental groups. The lymphoproliferative responses to PHA and Con A, of the 2 vaccinated groups were comparable to that of normal controls on day 45 p.c. The study suggests that ALD along with BCG can offer substantial protection against visceral leishmaniasis in hamsters.

High frequency of hepatitis B virus infection in patients with beta-thalassemia receiving multiple transfusions

BACKGROUND AND OBJECTIVES

Hepatitis B virus (HBV) may occasionally be transmitted through transfusion of blood units that are hepatitis B surface antigen (HBsAg) negative but HBV DNA positive. Children with beta-thalassemia are particularly susceptible to HBV because they receive multiple blood transfusions. These children have high infection rates despite vaccination against HBV. Post-vaccination infections may be a result of viruses harbouring surface (S)-gene mutations (e.g. G587A) in a region critical for reactivity to antibody to hepatitis B surface antigen (anti-HBs). The true prevalence of HBV in individuals with beta-thalassemia has not been studied previously.

PATIENTS AND METHODS

Seventy patients with beta-thalassemia (median age 6 years; range 8 months to 22 years; 49 male), who had received seven to 623 (median 61) units of blood each and three doses (10/20 micro g) of HBV vaccine (Engerix B) before presentation to us, were included in the study; 50 of the 70 patients had received transfusions prior to vaccination. Enzyme-linked immunoassay for serological markers [HBsAg, antibody to hepatitis B core antigen (anti-HBc) and quantitative anti-HBs] and polymerase chain reaction (PCR) followed by Southern hybridization for molecular detection of hepatitis B, was performed on all samples. The PCR-amplified product was cloned, sequenced and the nucleotide and deduced amino acid sequences for the HBV S and polymerase (P) genes were analysed for mutations.

RESULTS

Four of 70 (5.7%) individuals with beta-thalassemia were HBsAg positive and 14 (20%) were anti-HBc positive. The prevalence of serological markers increased with number of transfusions (P < 0.01). Of 70 patients, 53 (75.7%) had an anti-HBs titre of > 10 IU/l following vaccination and 17 (24.3%) were non-responders (< 10 IU/l); 22 (31.4%) of the 70 were DNA positive. The frequency of HBV infection in beta-thalassemia was similar in vaccine responders and non-responders. The virus was of subtype ayw (genotype D) in the five DNA-positive samples in which a 388-nucleotide region of the S gene was sequenced. Mutations occurred at 13 positions in the S gene and at 10 positions in the P gene. Hydrophobicity plots revealed differences in amino acid regions 117-165 and 195-211. Some of these amino acid substitutions coincided with the putative cytotoxic T-lymphocyte epitopes of both S and P proteins.

CONCLUSIONS

A high frequency of HBV infection was seen using molecular methods in thalassemic patients. The frequency of infection was similar in vaccine responders and non-responders. A number of mutations were observed in the S gene, which could have implications for viral replication as well as virus-host cell interaction.

Establishment of asymptomatic Leishmania donovani infection in Indian langurs (Presbytis entellus) through intradermal route

Indian langurs, which were previously reported to be highly susceptible, were infected intradermally using variable numbers of promastigotes along with different doses, 1/2 pair, 5 pairs and 10 pairs respectively of salivary gland lysate (SGL). Although, all the monkeys developed mild infection and remained subclinically infected throughout the observation period, which later resolved, none of them could develop the classical disease. No marked antigen specific antibody or lymphoproliferative response was noticed throughout the experimental period. However, a late IFN-gamma response (by day 90 pi.) was demonstrated in monkeys infected with 2 x 10(6) promastigotes +10 pairs SGL. It seems that a single intradermal dose of promastigotes with or without SGLs had a vaccines like effect. Perhaps, multiple frequent inoculations, as happens in the natural situation, may be necessary for the development of full-blown disease.

Successful vaccination against Leishmania donovani infection in Indian langur using alum-precipitated autoclaved Leishmania major with BCG

Autoclaved Leishmania major (ALM) along with BCG, presently undergoing phase II clinical trial by WHO for its vaccine potential against cutaneous leishmaniasis, has been successfully evaluated in single and triple dose schedules against L. donovani in Indian langurs (Presbytis entellus). Encouraged with the results, another formulation alum-precipitated ALM (provided by WHO) along with BCG has been evaluated in this system. Eight monkeys were vaccinated with alum-precipitated ALM + BCG (1 mg of each per animal) while four were kept as unvaccinated controls. All were challenged with 100 x 10(6) amastigotes i.v. on day 60 post vaccination. Parasitic assessment in splenic tissue was performed on day 45, 90 and 180 p.c. Initially, seven of the eight vaccinated monkeys developed infection (two to six amastigotes per 1000 cell nuclei), which resolved by day 180 p.c., while the eighth monkey had a parasite burden of 14 amastigotes per 1000 cell nuclei on day 45 p.c. and died on day 130 p.c. On the other hand, there was progressive infection in unvaccinated control animals and three out of four died between days 110 and 120 p.c., and one monkey, which had low parasite burden, died on day 178 p.c. Prior to challenge, there was an initial rise in antileishmanaial antibodies in the vaccinated group compared to the unvaccinated control group, which later came down to normal level, while it remained higher in the unvaccinated control group. An increasing pattern of antigen-specific proliferative responses and interferon-gamma level to the two antigens--autoclaved L. donovani (ALD) and ALM--was observed in vaccinated monkeys throughout the experiment. There was a good correlation between parasite burden and IFN-gamma level on days 90 and 180 p.c., indicating IFN-gamma response as a sensitive parameter of immune status. The findings suggest alum-precipitated ALM+BCG as a potential vaccine against visceral leishmaniasis and warrants clinical trials.

Recombinant hemagglutinin protein of rinderpest virus expressed in insect cells induces humoral and cell mediated immune responses in cattle

Rinderpest virus causes a highly contagious and often fatal disease in domestic and wild ruminants. The surface glycoproteins, hemagglutinin (H) and fusion (F) proteins of this enveloped virus are known to confer protective immunity in cattle. We have reported the generation of a recombinant baculovirus expressing H protein and studied its protective properties in cattle. In this report, we demonstrate that the recombinant baculovirus encoded H protein expressed in insect cells gets incorporated into extracellular baculovirus. Single administration of low doses of purified recombinant extracellular virus with or without adjuvant induces virus neutralizing antibody responses and bovine leukocyte antigen (BoLA) class II restricted helper T cell responses in cattle.

Mechanism of action of disease modifying anti-rheumatic agent, gold sodium thiomalate (GSTM)

GSTM has been used for long in the treatment of rheumatoid arthritis (RA). However, its mechanism of action is still poorly understood. In the last decade, tumor necrosis factor-alpha (TNF-alpha) has emerged as the major pro-inflammatory cytokine in the pathogenesis of RA. We studied the effect of GSTM on spontaneous and LPS-stimulated TNF-alpha production by human peripheral blood mononuclear cells (PBMCs) of normal volunteers. PBMCs were isolated from 20 normal volunteers and cultured in the presence of absence of lipopolysaccharide (LPS 10 ng/ml) and GSTM (1 microgram/ml). TNF-alpha level was measured using commercial enzyme-linked immunosorbent assay (ELISA) and reverse transcription-polymerase chain reaction (RT-PCR). The TNF-alpha response to LPS was heterogeneous. PBMCs of 24 subjects showed high LPS-stimulated TNF-alpha production (LPS-responsive group), whereas that of six individuals had low LPS-stimulated TNF-alpha production (LPS-non-responsive group). GSTM-stimulated spontaneous TNF-alpha production and inhibited LPS-stimulated TNF-alpha production in 16 of 24 (75%) individuals of LPS-responsive group and one of six individuals (17%) of LPS-non-responsive group. The suppression of TNF-alpha by GSTM was also demonstrated at the mRNA level. We conclude that there is a heterogeneity among normal population for TNF-alpha production in response to LPS, and GSTM inhibits LPS-stimulated TNF-alpha production, primarily in LPS responders. Further study is needed to establish the relationship between LPS responsiveness and GSTM suppression.

Simultaneous amplification of DNA and RNA virus using multiplex PCR system

A large number of disease-causing bacteria and viruses are being sequenced and PCR is increasingly used for the diagnosis of the diseases. We have designed a multiplex PCR system for hepatitis B virus (HBV), a DNA virus, and hepatitis E virus (HEV), an RNA virus. A modified technique has been standardized for simultaneous extraction of DNA and RNA, followed by a one-step RT-PCR/PCR.

Absence of Toll-like receptor 4 explains endotoxin hyporesponsiveness in human intestinal epithelium

BACKGROUND

The Toll protein in Drosophila regulates dorsal ventral patterning during embryogenesis, and participates in antibacterial and antifungal host defense. Mammalian homologues are termed Toll-like receptors and, to date, nine have been cloned (TLRI-9) in humans. They are characterized by extracellular leucine-rich repeats and a cytoplasmic domain similar to the interleukin 1 receptor. Both TLR2 and TLR4 recognize various bacterial cell wall components including lipopolysaccharide (LPS). This results in the activation of the NFkappaB pathway. Peripheral blood mononuclear cells (PBMCs) express both TLR2 and TLR4. The authors hypothesized that the expression of TLR 2 and TLR4 in human intestinal epithelial cells differs from PBMCs because of the abundance of LPS in the intestinal lumen.

METHODS

Epithelial cells were isolated from Caco-2 cells, fetal gut explants, and small bowel resection specimens using Hanks/ethylenediamine tetraacetic acid solution. PBMCs were used as positive controls. Ribonucleic acid (RNA) was isolated using the TRIzol method. Standard reverse transcription-polymerase chain reaction examined TLR2 and TLR4 messenger RNA (mRNA) expression. NFkappaB expression was determined using a luciferase reporter assay.

RESULTS

TLR2 mRNA was highly expressed in PBMCs and was present in all human intestinal epithelial cells. TLR4 mRNA was detected only in PBMCs. TLR4 is not present in epithelium from children with inflammatory bowel disease. In Caco-2 cells, significant NFkappaB activation in response to LPS occurred only in the presence of TLR4 introduced by complementary deoxyribonucleic acid transfection.

CONCLUSION

Absence of TLR4 is associated with endotoxin hyporesponsiveness of intestinal epithelial cells. TLR4 is not directly involved in inflammation of the intestinal epithelium. Although TLR2 is normally present in the epithelial cell, it plays a limited role in inflammation. It may be activated during conditions in which bacterial cell wall concentrations within the intestine are pathologically high.

Dietary regulation of intestinal gene expression

We are becoming increasingly aware of inherited genetic abnormalities as causes of disease. However, alterations in gene expression can also contribute to other disease processes. Recently it has been suggested that our environment may alter such genes and thus be a direct influence on disease. Diet is a potent mechanism for altering the environment of cells of most organs, particularly the gastrointestinal tract. This review addresses the influence of nutritional factors on intestinal gene regulation. These influences include insulin, which is not a dietary component but responds to dietary changes, and butyrate, a short chain fatty acid produced by normal intestinal flora. Manipulation of diet may be a means of treating intestinal disorders. Nutritional treatment therefore is also discussed in the light of its effect on gene expression.

Is immunoproliferative small intestinal disease uncommon in India?

Till date only three series of immunoproliferative small intestinal disease (IPSID) describing 22 patients have been reported from India. Seven patients with IPSID in two tertiary referral centers in India are included in the study. Diagnosis was based on typical clinical features [diarrhoea (7/7), weight loss (7/7), clubbing (6/7), fever (3/7), abdominal pain and lump (3/7)], biochemical evidence of malabsorption and duodenal biopsy findings. All patients were young males (mean age 29.8 +/- 11.8 years, range 17-53). Atypical features included gastric involvement (1/7), colonic involvement (1/7) and appearance of pigmented nails following anti-cancer chemotherapy (1/7) which disappeared six months after omitting doxorubin from chemotherapy regimen. Parasitic infestation was common. Ascaris lumbricoides (1/7), Giardia lamblia and hookworm (1/7), Strongyloides stercoralis and Trichuris trichura (1/7). In the latter patient S. stercoralis became disseminated after anti-malignant chemotherapy. One patient had gastric H. pylori infection. Four of the seven patients who were misdiagnosed as tropical sprue were treated with tetracycline. This raises doubt on efficacy of tetracycline alone in treatment of IPSID. One other patient was misdiagnosed and treated as intestinal tuberculosis. Early diagnosis and administration of chemotherapy may improve survival in this disease.

Cutting edge: C-C chemokine receptor 6 is essential for arrest of a subset of memory T cells on activated dermal microvascular endothelial cells under physiologic flow conditions in vitro

Memory T cells (mTC) express multiple chemokine receptors (including CCR4 and CCR6) that may potentially be involved in their arrest on inflamed endothelia. Herein, we specifically addressed whether CCR6 is required for mTC to arrest on TNF-alpha-activated human dermal microvascular endothelial cells (HDMEC) in vitro under shear stress conditions. Recombinant liver and activation-regulated chemokine (LARC)/CCL20 (a CCR6 ligand) induced firm arrest of cutaneous lymphocyte Ag(+) mTC in a flow chamber system using purified substrates. Strikingly, desensitization of CCR6 with LARC, but not thymus and activation-regulated chemokine/CCL17 or secondary lymphoid tissue chemokine/CCL21, caused a 50-75% decrease (p < 0. 001) in arrest of mTC on HDMEC, which was indistinguishable from the reduction observed when total mTC were treated with pertussis toxin (p > 0.5). CCR6-depleted mTC also had a markedly reduced ability to arrest on HDMEC. Our results suggest that LARC production by activated endothelial cells and CCR6 expression by mTC may be critical components in the pertussis toxin-sensitive arrest of mTC on activated HDMEC.

Phosphorothioate backbone modification modulates macrophage activation by CpG DNA

Macrophages respond to unmethylated CpG motifs present in nonmammalian DNA. Stabilized phosphorothioate-modified oligodeoxynucleotides (PS-ODN) containing CpG motifs form the basis of immunotherapeutic agents. In this study, we show that PS-ODN do not perfectly mimic native DNA in activation of macrophages. CpG-containing PS-ODN were active at 10- to 100-fold lower concentrations than corresponding phosphodiester ODN in maintenance of cell viability in the absence of CSF-1, in induction of NO production, and in activation of the IL-12 promoter. These enhancing effects are attributable to both increased stability and rate of uptake of the PS-ODN. By contrast, PS-ODN were almost inactive in down-modulation of the CSF-1R from primary macrophages and activation of the HIV-1 LTR. Delayed or poor activation of signaling components may contribute to this, as PS-ODN were slower and less effective at inducing phosphorylation of the extracellular signal-related kinases 1 and 2. In addition, at high concentrations, non-CpG PS-ODN specifically inhibited responses to CpG DNA, whereas nonstimulatory phosphodiester ODN had no such effect. Although nonstimulatory PS-ODN caused some inhibition of ODN uptake, this did not adequately explain the levels of inhibition of activity. The results demonstrate that the phosphorothioate backbone has both enhancing and inhibitory effects on macrophage responses to CpG DNA.

Metastatic extragonadal seminoma associated with cardiac transplantation

A 37-year-old man who had successfully undergone cardiac transplantation for dilated cardiomyopathy presented with a history of severe pain over his left shoulder, rib cage and thoracic spine. Clinical examination revealed the presence of bony tenderness over these sites, but there was no other clinical evidence of malignancy. Further investigations suggested the presence of multiple bony metastases. Bone biopsy revealed extensive bone marrow infiltration by large undifferentiated cells showing pronounced cytoplasmic vacuolation with a striking granulomatous reaction. Immunocytochemistry revealed these anaplastic cells to be cytokeratin and placenta-like alkaline phosphatase positive but S100, CD30 and lymphoid marker negative. Analyses by in situ hybridisation of these cells revealed no evidence of Epstein-Barr virus infection. Overall the pathology suggested a diagnosis of metastatic seminoma. Confirmation of this diagnosis was obtained by the analysis of serum human chorionic gonadotrophin which was elevated at 90 IU/l. In the absence of testicular or retroperitoneal disease, it is very likely that this unusual case of metastatic seminoma was related to the patient's immunosuppressive therapy, which at diagnosis included cyclosporin and prednisolone. The patient was successfully treated with cisplatin based chemotherapy and decreased immunosuppression and remains in complete remission one year after completion of chemotherapy. Seminoma is an uncommon complication of prolonged immunosuppression with very few cases being described in the literature post-organ transplantation. This case shows that the clinical presentation of this treatable tumour in this patient population can be unusual and difficult to diagnose.

Complement degradation product C3d in urine: marker of lupus nephritis

OBJECTIVE

To examine whether serum and urine C3d, a degradation product of C3, correlate with renal and extrarenal lupus activity.

METHODS

Serum and urinary C3d levels were measured by ELISA in 15 healthy individuals and 24 patients with systemic lupus erythematosus (SLE) (8 with inactive disease, 7 with active but nonrenal disease, 9 with active lupus nephritis). Disease activity variables like serum C3, C4, and anti-dsDNA antibodies were also measured.

RESULTS

The median serum C3d levels were significantly higher (p < 0.01) in patients with active (26 arbitrary units/ml; AU/ml) and inactive SLE (27 AU/ml) compared to healthy controls (11.25 AU/ml); levels were comparable in patients with active renal and extrarenal SLE. On the other hand, urine C3d was elevated only in patients with active SLE; its level was highest in patients with active lupus nephritis (0.87 AU/ml) compared to patients with active extrarenal diseases (0.31 AU/ml; p < 0.05), to patients with inactive lupus nephritis (0.06 AU/ml; p < 0.001), or to levels in healthy individuals (0.06; p < 0.001). Urine C3d showed stronger correlation with disease activity score (SLE Disease Activity Index) than serum C3, C4, anti-dsDNA antibodies, and serum C3d.

CONCLUSION

Urine C3d is a good index of active lupus, particularly lupus nephritis.

Leishmania donovani: cellular and humoral immune responses in Indian langur monkeys, Presbytis entellus

We have previously reported that disease mimicking human visceral leishmaniasis can be established in Presbytis entellus, the Indian langur monkey, following a single intravenous challenge of 10(8) Leishmania donovani amastigotes. In the present report, infection was assessed in monkeys infected intravenously with a single dose of 10(8) amastigotes (HDA group), three weekly doses of 10(7) amastigotes (LDA group) and three weekly doses of 5 x 10(7) promastigotes (HDP group). Typical clinical infection was established in all three groups with significant parasite load. There was a gradual and sustained rise in anti-leishmania specific immunoglobulin G response, and a severe fall in the lymphoproliferative response to the T cell mitogens PHA and Con A by day 80 post infection (p.i.). The antibody level remained elevated until death in monkeys of the HDA and HDP groups; the T-cell responses showed a recovery prior to death. T-cell responses to leishmania antigen, however, could not be demonstrated in any of these monkeys prior to death. One monkey of the LDA group survived for 155 days and two monkeys spontaneously eradicated the infection. Surprisingly, one monkey of the HDA group also achieved spontaneous cure. In the three monkeys which eradicated infection spontaneously, the antibody level declined to baseline levels on day 180 p.i. with a well demonstrable antigen specific lymphoproliferative response; no parasites could be demonstrated in splenic aspirates by direct examination of culture. These data demonstrate that disease severity may be the function of the total inoculum dose rather than the stage of the parasite and that the immunological responses in the Indian langur model parallel the reported changes in human visceral leishmaniasis. This makes the langur a potentially useful model for the evaluation of candidate anti-leishmanial drugs and vaccines.

Characterization and evaluation of detoxification functions of a nontumorigenic immortalized porcine hepatocyte cell line (HepLiu)

Primary porcine hepatocytes (PPH) are currently used in research and therapeutic applications as the biological component of extracorporeal liver assist devices to overcome the shortage of human hepatocytes. However, their finite life span and typically rapid loss of functions limit their utility. An immortalized, nontumorigenic, highly differentiated porcine hepatocyte cell line was developed in our laboratory to resolve these disadvantages. PPH were transfected with simian virus 40 (SV40) T antigen under the control of the SV40 early promoter. From the established 69 clones, 23 clones displaying hepatocyte-like morphology were screened for diazepam metabolism. One clone, HepLiu D63, has been maintained in culture for > 2 years, through more than 60 passages and 240 divisions. Albumin protein, present in early passages, was lost at later passages, but albumin transcript still was detectable in later passages. Carbamoyl phosphate synthetase, a gateway enzyme of the urea cycle, was consistently detectable in HepLiu cells. Cytokeratin 18, a characteristic marker of primary hepatocytes, was detected by both immunofluorescent staining and Western blot in HepLiu cells. Furthermore, maintenance of P450 functions in HepLiu cells was evidenced by diazepam and 7-ethoxycoumarin metabolites measured by HPLC. Phase II conjugative function was measured as acetaminophen glucuronidation. P450 dealkylase was demonstrated microscopically by the conversion of a nonfluorescent substrate to a fluorescent product. Both Northern blot analysis and immunofluorescent staining showed SV40 T antigen expression in the nuclei of HepLiu cells. No tumor formation occurred when HepLiu cells were injected into severe combined immunodeficient (SCID) mice nor was the TAI (a tumor marker) mRNA expressed, even in later passages. This immortalized, nontumorigenic, highly functional cell line may provide a valuable tool for drug/toxicological studies, liver biologic regulation studies, and artificial liver support systems.

Prediction of prolonged ventilator dependence in children by respiratory function measurements

Complications of ventilatory support are more common if this assistance is prolonged. Our aim was to determine if results of respiratory function measurement on the first day of ventilation identified children who would develop prolonged ventilatory dependence (> or = 4 days) and whether such results were a more accurate predictor than readily available clinical data. Thirty three children, median age 2 years (range 0.1-13.6), who were supported by a constant flow ventilator and hence had measurements of compliance of the respiratory system (CRS) and resistance of the respiratory system (RRS) on the first day of ventilatory support, were retrospectively identified. Those who needed prolonged ventilatory support had a lower CRS on day one (p < 0.01) and required at any time during their ventilatory career both a higher maximum inspired oxygen concentration (p < 0.01) and peak inspiratory pressure (PIP) (p < 0.01). Logistic regression analysis demonstrated that only a low CRS and high maximum PIP were significantly correlated with prolonged ventilator dependence. A low CRS (<0.4 (ml/cmH2O) kg(-1)) and a high maximum PIP (>27 cmH2O) had similar sensitivities (83%) and specificities (71% and 67% respectively) in predicting prolonged ventilatory dependence. The CRS results, unlike the maximum PIP results, however, were always available on the first day of ventilatory support. We therefore conclude that respiratory function measurements have a role in identifying children who would benefit from strategies to prevent prolonged ventilator dependence.

Vaccine potential of 56-66 kDa protease secreted by Entamoeba histolytica

Excretory/secretory (ES) antigens and sub-cellular fractions of E. histolytica (HM1:IMSS strain) were tested for the presence of common proteases using substrate gel electrophoresis. We obtained two E. histolytica proteases (56-66 kDa and 29 kDa) from ES material, soluble components and plasma membrane. Protease 56-66 kDa from ES antigen was selected for immunizing hamsters because it gave a consistent broad band. We observed 62.5 per cent protection in immunized animals, compared to 0 per cent in unimmunized controls. Although all vaccinated golden hamsters showed high antibody response, there was no correlation between antibody titres and protection. 56-66 kDa ES protease could thus prevent disease and could be a candidate molecular vaccine against amoebiasis.

Pigmented nails and Strongyloides stercoralis infestation causing clinical worsening in a patient treated for immunoproliferative small intestinal disease: two unusual observations

Immunoproliferative small intestinal disease (IPSID) is commonly reported from developing countries with poor socioeconomic conditions, hygiene, and high frequency of gastrointestinal infections and infestations. The disease requires anti-malignant chemotherapy in lymphomatous stage. Reported here is a 20-year old man with IPSID lymphoma who responded to anti-malignant chemotherapy initially, but later deteriorated due to Strongyloides stercoralis infestation, which was treated successfully with mebendazole. Importance of an early recognition and adequate treatment for gastrointestinal infections and infestations before anti-malignant chemotherapy for this disease is highlighted considering the occurrence of this disease in the developing world. The patient developed alternate brown black and white lines in the finger nails after combination chemotherapy, which has not been reported earlier in this disease; the nail changes disappeared 6 months after the withdrawal of doxorubicin suggesting this drug as the cause for such nail changes during anti-malignant combination chemotherapy.

Effect of passively transferred anti-poliovirus antibodies on seroconversion

A prospective study enrolling 50 mother-infant pairs was undertaken to determine the effect of maternal antibodies on poliovirus antibody titres and seroconversion rates in infants and to determine the difference in titres and seroconversion rates following three and five doses of oral poliovaccine (OPV). Cord blood samples and samples collected 4 weeks after 3rd and 5th doses of trivalent oral poliovaccine were processed for estimation of anti-poliovirus antibody titres. These were expressed as geometric mean titres (GMT). Significance was analyzed using unpaired 't' test. The relationship between maternal antibody titres and seroconversion was determined by correlation coefficient test. Post OPV5 titres were significantly higher than post OPV3 titres for type 1 and type 2 polioviruses. Seroconversion rates against type 1, 2 and 3 polioviruses were 92.9%, 100.0% and 92.9% following OPV3 and 100.0%, 100.0% and 93.2% following OPV5. The cord blood titres did not have any relation to post-OPV3 or post-OPV5 titres. Although there is significant passive transfer of poliovirus antibodies across the placenta, this does not affect titres achieved after immunization. Post-OPV5 titres against type 1 and type 2 viruses are significantly higher than post-OPV3 titres. The seroconversion rates following OPV5 are higher than those obtained post-OPV3 but this difference is not statistically significant.

Isoenzyme and molecular characterization of Entamoeba histolytica and Entamoeba dispar isolates from symptomatic and asymptomatic subjects

AIM

To correlate the clinical features of amebic infections with the characteristics of Entamoeba culture isolates of stools.

METHODS

Isolates from seven irritable bowel syndrome (IBS) patients, four asymptomatic cyst passers (ACP) and five patients with invasive amebic disease were subjected to hexokinase polyacrylamide electrophoresis (HK-PAGE) and their DNA subjected to restriction fragment (RF) analysis of amplified polymerase chain reaction (PCR) products. These findings were correlated with anti-amebic serology. Two axenic pathogenic strains (HM1:IMSS, NIH:200) and one xenic nonpathogenic strain (SAW1734) were used as standards.

RESULTS

All isolates from IBS patients as well as ACP had slow-moving (nonpathogenic) band pattern, whereas those from patients with invasive disease had fast-moving (pathogenic) band pattern on HK-PAGE. Serological data using EIA and RF patterns of PCR-amplified genome corroborated these results.

CONCLUSIONS

Our results support the view that there are two species of Entamoeba infecting humans--E. histolytica(pathogenic) and E. dispar (nonpathogenic), and HK-PAGE of culture isolates can differentiate between them.

Sparfloxacin in the treatment of purulent sinusitis-a multicentric study in Indian patients

Sparfloxacin, a new quinolone antibacterial was used to treat one hundred and thirty two patients with acute purulent sinusitis, at a dosage of 400 mg on the first day followed by 200 mg once daily for a further four days. A clinically successful outcome (defined as disappearance of nasal discharge, fever, pain, tenderness over the sinuses and headache) was recorded in 122 ( 95.3%) patients. Sparfloxacin was well tolerated. Fourteen adverse experiences were reported in 7 patients ( 5.3%); they were mainly gastrointestinal and mild. No phototoxic or cardiological adverse events occurred. An unusual feature was that Staphylococcus aureus and Pseudomonas spp. were the most common bacterial species isolated from middle meatal was of patients in this study.

Effect of bacterial association on virulence of Entamoeba histolytica to baby hamster kidney cell monolayers

Axenic E. histolytica trophozoite strain NIH:200 and HMI:IMSS when co-associated with aerobic bacteria Escherichia coli strain K12 and serotype 056 showed marked increase in virulence as observed by destruction of baby hamster kidney (BHK) monolayers. However, when incubated with anaerobic bacterial strains Clostridium perfringens and Bacteroides fragilis virulence remained unaltered. Further, adherence of E. histolytica to BHK monolayer was found to be mediated by N-acetyl-D-galactosamine.

Lack of in vitro lymphoproliferative response to hepatitis B surface antigen in healthy vaccine recipients

A majority of HBsAg vaccine recipients show good anti-HBs antibody responses but poor antigen specific lymphoproliferative responses. We investigated the basis for this poor in vitro antigen specific proliferative responsiveness in vaccinees who had received the standard three dose schedule (0, 1 and 6 months) of plasma derived HBsAg vaccine. Peripheral blood mononuclear cells (PBMC) from 26 of 29 (89.7%) vaccinees failed to show lymphoproliferative responses to HBsAg in spite of having a very good anti-HBs antibody response (geometric mean titre 3154 IU/1). The mitogen (phytohaemagglutinin, PHA) and antigen (purified protein derivative, PPD) driven lymphoproliferative responses in these individuals were normal. Addition of exogenous recombinant interleukin-2 (rIL-2) along with HBsAg had no effect in the response to HBsAg in six of nine vaccinees, who were tested six months after the third vaccine dose or in four unvaccinated controls. However, in three vaccinees who did not have lymphoproliferative response to HBsAg alone, addition of exogenous rIL-2 resulted in a synergistic response. These data suggest that HBsAg reactive cells are few in the peripheral circulation of a majority of individuals following the standard three dose schedule of vaccination and addition of exogenous rIL-2 induces a response only in a subgroup of individuals. The inability of HBsAg to induce a T cell proliferative response may have implications for the maintenance of protective immunity and immunological memory following vaccination.

Perinatal lung function measurements and prediction of respiratory problems in infancy

The aim of this study was to determine which lung function test employed in the perinatal period gave the results most significantly associated with respiratory problems in infancy. The ratio of the proportion of time to reach peak tidal expiratory flow to total expiratory time (tPTEF:tE), thoracic gas volume (TGV) and airway resistance (R(aw)) (from which specific conductance (SG(aw)) was calculated) measurements were examined from 85 infants born at or near term. The infants were followed until at least one year of age and described as symptomatic if they wheezed for at least 24 hours. Twenty-three infants were symptomatic in the first year. The symptomatic group, compared to the asymptomatic, had a higher median FRC (p < 0.01) and R(aw) (p < 0.001); their median SG(aw) was lower (p < 0.001). It was possible to obtain tPTEF:tE results from only 61 infants; the median tPTEF:tE did not differ significantly between symptomatic and asymptomatic infants. Logistic regression analysis demonstrated a high R(aw) and FRC, but not a low tPTEF:tE, independently related to positive symptom status. A high R(aw) (>26 cm H2O (1 s(-1))(-1)) was the most sensitive (83%) predictor of subsequent respiratory problems, but all the tests examined had low positive predictive values.

Chronic hepatitis B virus carriers have low lymphoproliferative responses to HBsAg and reduced interleukin-2 synthesis

BACKGROUND

Chronic carriers of hepatitis B virus (HBV) have impairment of lymphoproliferative responses. Recently HBV infection of peripheral blood mononuclear cells (PBMC) has been reported. The defect in the proliferative capacity of carrier PBMC has not been correlated to the presence of HBV in these cells.

METHODS

PBMC of fourteen HBV carriers and 14 healthy individuals were stimulated with phytohemagglutinin (PHA), pokeweed mitogen (PWM) or anti-CD3 for 3 days and with HBsAg and purified protein derivative (PPD) for 6 days. The supernatants of unstimulated and PHA-stimulated PBMC cultures were bioassayed for interleukin-2 (IL-2); the supernatants of unstimulated and lipopolysaccharide (LPS)-stimulated cultures were bioassayed for IL-1. DNA extracted from PBMC was hybridized with a 32P-labeled HBV probe to look for HBV DNA.

RESULTS

HBV carriers' PBMC showed impaired responses to PHA, PWM and anti-CD3. No carrier demonstrated lymphoproliferative response to hepatitis B surface antigen (HBsAg). Seven of eight carriers with impaired HBsAg-specific proliferative responses who were tested for their response to an unrelated antigen showed a positive response to PPD. PBMC from HBV carriers produced similar amounts of IL-1 as normal PBMC on LPS stimulation; however, they produced significantly lower amounts of IL-2 as compared to normal PBMC under both spontaneous and PHA-stimulated conditions. HBV DNA was demonstrable in the PBMC of all fourteen carriers.

CONCLUSIONS

The abnormal immune function found in chronic HBV carriers may be a consequence of replicative viral infection of the mononuclear cells.

Proteinase activity & virulence of Entamoeba histolytica on passage through hamster liver

This study was undertaken to determine the enzymatic differences in the process of increasing the degree of virulence in E. histolytica successively passaged in hamster liver. Substrate gel electrophoresis was used to compare proteinase banding patterns under reducing conditions from whole cell lysates of one axenic E. histolytica (strain HM1:IMSS) and five xenic isolates of the same strain of E. histolytica passaged five times through hamster liver. Trophozoites successively passaged in hamster liver showed in supernatants, major bands in the 56-97 kDa region whereas only the axenic strain produced additional band at 34 KDa. Inoculation of amoebic trophozoites into hamster led to progressive increase in proteinase activity of supernatants as well as increased virulence of amoebae; proteinase activity of amoebae showed an excellent correlation with their virulence. All the infected animals died when activity of proteinase was 0.152 mg of protein.

Manoeuvres to elevate mean airway pressure, effects on blood gases and lung function in children with and without pulmonary pathology

During mechanical ventilation, mean airway pressure (MAP) can be increased by a variety of manoeuvres, for example increasing inspiratory time or elevating the positive end expiratory pressure (PEEP). It seemed likely that the effect on blood gases and lung function of a particular manoeuvre to increase MAP would be influenced by the presence of respiratory pathology and thus the manoeuvre best at improving respiratory status in children with an abnormal chest radiograph appearance would differ from that most efficacious in children without such a problem. The aim of this study was to test that hypothesis. Twenty-two children, median age 15 months (range 2.5 weeks-10 years) were examined. Group 1 (n = 10) had no chest radiograph abnormalities and group 2 (n = 12) lobar collapse and/or consolidation. The patients were studied at baseline settings and at an elevated MAP resulting from (in random order) an increase in inspiratory time (T1), pressure PEEP or peak inspiratory pressure (PIP). In group 1, elevating PIP improved oxygenation and carbon dioxide elimination (P < 0.01) and prolonging T1 improved oxygenation (P < 0.05). In group 2, only raising PEEP significantly improved oxygenation (P < 0.01), but this was associated with carbon dioxide retention (P < 0.01).

CONCLUSION

The presence of lung pathology does influence which manoeuvre should be used to elevate MAP to improve blood gases in the paediatric population.

RNase L dimerization in a mammalian two-hybrid system in response to 2',5'-oligoadenylates

RNase L, a key enzyme in the anti-viral activity of interferons, requires activation by 2',5'-linked oligoadenylates (2-5A) to cleave viral and cellular single-stranded RNA. Here we demonstrate that 2-5A causes formation of stable dimers of RNase L in intact human cells as measured with a mammalian two-hybrid system. Hybrid proteins consisting of the GAL4 DNA binding domain fused to RNase L and the VP16 transactivation domain fused to RNase L were able to associate and drive transcription of a reporter gene, but only after cells were transfected with 2-5A. Several functional forms of 2-5A, such as p3A2'p5'A2'p5'A, were capable of activating transcription in human HeLa cells. In contrast, p3A2'p5'A, which can neither activate nor dimerize RNase L, did not induce gene expression. Evidence for the involvement of the C-terminal region of RNase L in dimerization was obtained by expressing truncated forms of RNase L. These findings describe a convenient, high-throughput screening method for RNase L activators which could lead to the discovery of novel anti-viral and anti-cancer agents.

Vaccination of langur monkeys (Presbytis entellus) against Leishmania donovani with autoclaved L. major plus BCG

The protective potential of killed Leishmania major (ALM) along with BCG was evaluated against L. donovani in Indian langur monkeys in single and triple dose schedules. A delayed protection was observed in monkeys after a single dose schedule of ALM (3 mg)+BCG (3 mg) given intradermally 2 months before intravenous challenge with L. donovani. Triple dose schedule each of 1 mg ALM + 1 mg BCG was more effective. The status remained unchanged until the end of the experiment (approximately 8 months). The study indicates that a combination of ALM + BCG may be a good candidate vaccine for exploiting against human Kala-azar.

Prospective study of lung volumes in young asthmatic children

In a 9-y prospective study, the occurrence and duration of lung volume abnormalities in 21 young asthmatic children (median age at recruitment 4 y, range 3-8 y) was determined. The median functional residual capacity (FRC) at recruitment was 135% of that predicted for height (range 79-187%) and 13 children were hyperinflated. The median FRC decreased significantly after 3 y of follow-up and by 9 y only one child remained hyperinflated. We conclude that persistent elevation of lung volume in young asthmatic children appears to be uncommon.

First trimester invasive procedures: effects on symptom status and lung volume in very young children

First trimester procedures have been associated with perinatal lung function abnormalities that may suggest subsequent respiratory problems. Our aim was, therefore, to assess the impact of first trimester invasive procedures [early amniocentesis (EA) and chorion villus sampling (CVS)] on respiratory morbidity in very young children. A questionnaire was issued to parents of 439 EA and 453 CVS (subjects), and 435 controls (their mothers had undergone no invasive procedures) when their children were one year old. Data were also obtained from diary cards issued to a subset of 278 of the EA, 262 of the CVS, and 264 of the control infants followed prospectively. Functional residual capacity (FRC) was measured at a median age of 5 months (range: 0.25-24) in 159 children whose mothers had undergone EA, 168 following CVS and in 165 controls. Analysis of the one-year questionnaire demonstrated an excess of symptomatic infants in the EA group (31%) compared to the CVS (22%; P < 0.01) and control groups (17%; P < 0.01). Findings from the prospective follow-up study confirmed those results and also demonstrated an increase in chest-related hospital admissions in the EA group (3%) compared to the controls (0.4%; P < 0.05). Logistic regression analysis revealed that positive symptom status related significantly to EA and CVS interventions (P < 0.0001), bottle feeding (P < 0.001), parental smoking (P < 0.01), a family history of atopy (P < 0.01), and immaturity (P < 0.01). In the control group, FRC correlated best with weight (r = 0.92). The mean FRC of the EA and CVS groups was higher than that of the controls (P < 0.01). A higher proportion of children had an FRC two standard deviations above the controls' mean in the EA group (n = 14) compared to the CVS group (n = 3; P < 0.01). The symptomatic infants tended to have higher FRCs than the asymptomatic children. We conclude that first trimester procedures are associated with increased respiratory morbidity in very young children.

Interferon action and apoptosis are defective in mice devoid of 2',5'-oligoadenylate-dependent RNase L

2',5'-Oligoadenylate-dependent RNase L functions in the interferon-inducible, RNA decay pathway known as the 2-5A system. To determine the physiological roles of the 2-5A system, mice were generated with a targeted disruption of the RNase L gene. The antiviral effect of interferon alpha was impaired in RNase L-/- mice providing the first evidence that the 2-5A system functions as an antiviral pathway in animals. In addition, remarkably enlarged thymuses in the RNase L-/- mice resulted from a suppression of apoptosis. There was a 2-fold decrease in apoptosis in vivo in the thymuses and spleens of RNase L-/- mice. Furthermore, apoptosis was substantially suppressed in RNase L-/- thymocytes and fibroblasts treated with different apoptotic agents. These results suggest that both interferon action and apoptosis can be controlled at the level of RNA stability by RNase L. Another implication is that the 2-5A system is likely to contribute to the antiviral activity of interferon by inducing apoptosis of infected cells.

Transcriptional activation of the intercellular adhesion molecule 1 (CD54) gene by human T lymphotropic virus types I and II Tax is mediated through a palindromic response element

In vitro infection of T cells with human T lymphotropic virus types I and II (HTLV-I and HTLV-II) resulted in constitutive expression of ICAM-1. Higher levels of ICAM-1 mRNA were expressed in HTLV-transformed cell lines (MT-2, MoT, C8166) when compared with uninfected T cell lines (A301). We demonstrate that this activation is conferred through a site on the ICAM-1 promoter that is activated in trans by the Tax protein of HTLV-I and HTLV-II. Enhanced promoter activity was detected when the ICAM-1 construct (-1162/+1) was transfected into HTLV-I-infected (MT-2), HTLV-II-infected (MoT, AI 1050), or an HTLV-I Tax-only-expressing (C8166) cell line as compared to the uninfected T cell line (A3.01). Cotransfection of the uninfected T cell line A3.01 with the ICAM construct along with Tax-I and Tax-II expression plasmid also resulted in increased promoter activity. Furthermore, experiments with deletion constructs of the ICAM-1 promoter region indicated that a region between -88 and -53 bp relative to the transcription start site is sufficient for Tax-inducible CAT expression. This segment includes an 11-bp palindromic segment (TTTCCGGGAAA) that has homology with the IFN-gamma and IL-6 response element. An 11-bp segment containing this regulatory region proved to be sufficient to confer Tax-I and Tax-II inducibility on a heterologous promoter (TK-CAT). Taken together these findings indicate that constitutive expression of ICAM-1 by HTLV-infected cells is influenced by the viral trans-activator protein Tax. This increased expression of ICAM-1 in response to the Tax protein may play an important role in the lymphoproliferation associated with HTLV infection.

First-trimester invasive procedures and congenital abnormalities

A prospective study was undertaken to determine whether first-trimester amniocentesis or chorion villus sampling was associated with an increased incidence of congenital anomalies. The infants of mothers who had undergone first-trimester amniocentesis (EA) (n = 352), chorion villus sampling (CVS) (n = 348) or no invasive antenatal procedure (controls) (n = 264) were examined at a median age of 5 months. Both the EA and CVS groups had a higher proportion of infants with congenital anomalies (n = 18 and n = 22, respectively) than the control group (n = 4) (p < 0.01). Certain of the abnormalities, however, affected only single infants. Compression abnormalities were more common in the EA group than in the controls (p < 0.05), but not in the CVS group. The isolated limb abnormalities which occurred were minor anomalies affecting the digits and were seen in both the CVS (n = 6) and EA (n = 3) groups. First-trimester invasive procedures are thus associated with an excess of congenital anomalies.

Does Entamoeba histolytica cause irritable bowel syndrome?

BACKGROUND

Symptoms of patients with irritable bowel syndrome (IBS) closely mimic those of patients with non-dysenteric amebic colitis.

AIM

To examine the clinical relevance of presence and types of Entamoeba histolytica in stools of patients with IBS.

METHODS

IBS was diagnosed by Manning's criteria. Stool examination was done 4-weekly for 48 weeks to detect E. histolytica cysts or trophozoites. Patients underwent initial sigmoidoscopy. Sera of 22 IBS patients, 23 asymptomatic cyst passers and 36 healthy volunteers whose stools were also examined were tested for presence of antiamebic antibodies. Stools were cultured for amebae; positive cultures were subjected to polyacrylamide-gel electrophoresis (PAGE) using hexokinase (HK) isoenzyme to distinguish between pathogenic (fast-moving band) E. histolytica infection and nonpathogenic (slow band) species of Entamoeba dispar.

RESULTS

E. histolytica cultured from stool samples of four IBS patients had slow-moving band of HK on PAGE. All patients spontaneously eradicated the infection during the next eight to 24 weeks; all had negative serology for antiamebic antibodies, and normal rectal mucosa on sigmoidoscopy. No change in symptom score occurred on follow up in IBS patients, although all of them cleared the infection. Three additional E. histolytica isolates from IBS patients obtained from another laboratory also showed nonpathogenic isoenzyme pattern.

CONCLUSION

Bowel symptoms in IBS patients were not related to E. histolytica infection. The term non-dysenteric amebic colitis thus appears to be inappropriate, since it may be used erroneously for patients with IBS with nonpathogenic ameba, leading to injudicious treatment with antiamebic drugs.

Functional recovery of porcine hepatocytes after hypothermic or cryogenic preservation for liver support systems

The provision of an immediate supply of isolated porcine hepatocytes for artificial liver support requires preservation techniques that will allow maintenance of cell viability and detoxification functions. By means of a simple and cost-effective cryopreservation system, porcine hepatocytes can be available for both local and distant medical treatment facilities. Additionally, cryopreservation provides an adequate period for quality control testing to be completed prior to use of any specific cell lot. We are reporting a dual approach, namely the preservation of porcine hepatocytes, at 4 degrees C and at -196 degrees C in liquid nitrogen (LN2). Using a combination of cryoprotectant agents with Chee's modified Eagle's culture media (CEM), collagenase isolated hepatocytes stored at 4 degrees C for 24 h maintained 80% of the initial diazepam metabolism measured in freshly isolated cells and nearly 100% of initial function was preserved in hepatocytes stored up to 6 mo at -196 degrees C. University of Wisconsin solution (UW) was also tested and while adequate for 4 degrees C storage, it certainly did not match the performance of the CEM formulations for preservation of metabolic function of cells stored in liquid nitrogen. Based on our results of viability and detoxification function the combination of CEM with DMSO, polyethylene glycol and serum provided optimal protection for LN2 frozen cells. Other findings in these studies underlined the importance of the gradual introduction of DMSO in the prefreezing process, the period of osmotic equilibration, and the rapid postthaw withdrawal of this agent to minimize cytotoxic effects at these critical stages. Our freezing methodology provides the foundation for further technological developments in the cryopreservation of the large numbers of cells (billions) that are necessary for extracorporeal liver assist devices.

Functional implications of hepatitis B surface antigen (HBsAg) in the T cells of chronic HBV carriers

This study was undertaken to investigate the role of T-lymphocyte-derived soluble factors in the maintenance of the hepatitis B virus (HBV) chronic carrier state. Cell-free supernatants from the peripheral blood T lymphocytes of chronic HBV carriers were produced by incubating them for 48 h in tissue culture medium. These supernatants were added to in vitro hepatitis B s antibody (HBsAb)-producing cultures of peripheral blood mononuclear cells from hepatitis B surface antigen (HBsAg) vaccinees stimulated with HBsAg or pokeweed mitogen. T-cell supernatants from chronic carriers suppressed in vitro HBsAb antibody synthesis, whereas those from control subjects did not. This suppression was antigen specific as the supernatants did not suppress synthesis of total IgG or IgM. HBV viral sequences were demonstrable, by Southern and dot-blot hybridization, in the T cells secreting this factor. We also demonstrated the presence of HBsAg in T-cell supernatants derived from these cells. These results show that HBsAg of T-cell origin may have a role in suppressing HBsAb production. Our observations point to the role of HBsAg-specific cellular and humoral responses in favouring persistence of the chronic HBV carrier state.

Invasive antenatal procedures and requirement for neonatal intensive care unit admission

Neonatal respiratory difficulties are increased following second trimester amniocentesis. In preterm, prolonged rupture of the membranes, respiratory outcome is particularly poor when rupture occurs in the first trimester. It therefore seems likely that first trimester/ early amniocentesis (EA) would be associated with severe respiratory problems necessitating a high neonatal intensive care unit (NICU) admission rate. To test that hypothesis, the requirement for admission to the NICU of 278 infants whose mothers had undergone EA, 262 whose mothers had undergone chorion villus sampling (CVS group) and 264 controls whose mothers had undergone no invasive procedures were reviewed as were their diagnoses if they needed admission. There was no significant difference in the mode of delivery, gestational age or gender distribution of the three groups and the median maternal age of the EA and CVS groups was similar. Nineteen EA, eight CVS and five control infants required admission to the NICU (EA versus controls, P < 0.01; EA versus CVS plus controls, P < 0.005). Nine EA, one CVS and four control infants had suffered respiratory problems (EA versus CVS P < 0.05). Logistic regression analysis demonstrated that immaturity and EA were significantly associated with a requirement for NICU admission. We conclude infants whose mothers have undergone EA may be at increased risk for NICU admission, this is partly due to respiratory problems but the association is uncommon.

The effect of in vitro bacterial association on virulence of Entamoeba histolytica

When trophozoites of axenic E. histolytica strains NIH : 200 were associated in vitro with Escherichia coli K12 for three hours at 37 degrees C, the virulence was enhanced as shown by increased cytopathogenicity to baby hamster kidney (BHK) cell monolayer. Further, the trophozoites were observed to adhere to the polystyrene surface, a hitherto unreported phenomenon. The co-association of E. histolytica trophozoites with Bacteroides fragilis and Clostridium perfringens for three hours duration at 37 degrees C neither led to increase in cytotoxicity potential nor to adherence phenomenon; in contrast significant inhibition of cytotoxicity was observed. We have thus shown that while co-association of E. histolytica (NIH : 200) with E. coli K12 leads to enhanced amoebic virulence, that with anaerobic bacteric leads to its inhibition.

Immunogenic and protective properties of haemagglutinin protein (H) of rinderpest virus expressed by a recombinant baculovirus

The hemagglutinin (H) protein of Rinderpest virus expressed by a recombinant baculovirus used as a vaccine produced high titres of neutralizing antibody to Rinderpest virus in the vaccinated cattle, comparable to the levels produced by live attenuated vaccine. The immunized cattle were protected against a vaccine-virus challenge, as demonstrated by the failure of development of antibodies to N protein of the vaccine virus. The lack of replication of vaccine virus in the immunized cattle indicated that they are capable of showing a protective response if challenged with a virulent virus.