Comparison of pneumococcal immunogenicity elicited by the PCV13 and PCV15 vaccines in adults 18 through 49 years of age

AIM

Pneumococcal conjugate vaccines (PCV13, PCV15, PCV20) effectively target the capsular polysaccharides of the most common disease-causing Streptococcus pneumoniae serotypes. In this short communication, we analyzed healthy participants who received PCV13 and PCV15 vaccines as part of a recently concluded exploratory clinical trial and report antibody responses to the 13 shared serotypes (1, 3, 4, 5, 6A, 6B, 7F, 9V, 14, 18C, 19A, 19F, and 23F) as well as functional OPA responses to serotype 3.

METHODS

Sera from 87 adult participants (18 through 49 years of age) randomized to receive either PCV13 or PCV15 were collected (n = 46 or n = 41, respectively), from 17 study centers in the US. IgG concentrations of the 13 shared serotypes and serotype 3-specific OPA titers were analyzed before and 1 month after vaccination using internally validated assays.

RESULTS

At 1 month after vaccination, IgG GMCs of the 13 shared serotypes in PCV13 were similar to those for PCV15. Specifically, serotype 3 OPA GMTs and 95% CIs were similar 1 month after vaccination for PCV13 (62.9 [48.9, 80.9]) and PCV15 (71.1 [50.9, 99.2]).

CONCLUSION

In healthy participants who received either PCV13 or PCV15, similar serotype-specific responses were observed between all shared serotypes when a uniform validated internal assay was used. Of note, data from this study suggest that both vaccines induce similar functional antibody responses against pneumococcal serotype 3.

Innate Immune Responses to Chimpanzee Adenovirus Vector 155 Vaccination in Mice and Monkeys

Replication-deficient chimpanzee adenovirus (ChAd) vectors represent an attractive vaccine platform and are thus employed as vaccine candidates against several infectious diseases. Since inducing effective immunity depends on the interplay between innate and adaptive immunity, a deeper understanding of innate immune responses elicited by intramuscularly injected ChAd vectors in tissues can advance the platform’s development. Using different candidate vaccines based on the Group C ChAd type 155 (ChAd155) vector, we characterized early immune responses in injected muscles and draining lymph nodes (dLNs) from mice, and complemented these analyses by evaluating cytokine responses and gene expression patterns in peripheral blood from ChAd155-injected macaques. In mice, vector DNA levels gradually decreased post-immunization, but local transgene mRNA expression exhibited two transient peaks [at 6 h and Day (D)5], which were most obvious in dLNs. This dynamic pattern was mirrored by the innate responses in tissues, which developed as early as 1–3 h (cytokines/chemokines) or D1 (immune cells) post-vaccination. They were characterized by a CCL2- and CXCL9/10-dominated chemokine profile, peaking at 6 h (with CXCL10/CCL2 signals also detectable in serum) and D7, and clear immune-cell infiltration peaks at D1/D2 and D6/D7. Experiments with a green fluorescent protein-expressing ChAd155 vector revealed infiltrating hematopoietic cell subsets at the injection site. Cell infiltrates comprised mostly monocytes in muscles, and NK cells, T cells, dendritic cells, monocytes, and B cells in dLNs. Similar bimodal dynamics were observed in whole-blood gene signatures in macaques: most of the 17 enriched immune/innate signaling pathways were significantly upregulated at D1 and D7 and downregulated at D3, and clustering analysis revealed stronger similarities between D1 and D7 signatures versus the D3 signature. Serum cytokine responses (CXCL10, IL1Ra, and low-level IFN-α) in macaques were predominantly observed at D1. Altogether, the early immune responses exhibited bimodal kinetics with transient peaks at D1/D2 and D6/D7, mostly with an IFN-associated signature, and these features were remarkably consistent across most analyzed parameters in murine tissues and macaque blood. These compelling observations reveal a novel aspect of the dynamics of innate immunity induced by ChAd155-vectored vaccines, and contribute to ongoing research to better understand how adenovectors can promote vaccine-induced immunity.

Role of structures in the masticator space in selecting patients with resectable T4b oral cancer: findings from a survival analysis

Oral squamous cell cancers involving the masticatory space are staged as unresectable cancers and their treatment is difficult. Curative treatment with extensive surgery followed by adjuvant therapy is one of the treatment options. In this retrospective study, the survival of 123 patients (93 with T4a cancers, 30 with T4b cancers), treated during the period August 2009 to August 2015, was evaluated. The majority had bucco-alveolar cancers (62.6%), were male (61.8%), and were tobacco users (76.4%). The select group of T4b oral cancer patients were treated with surgery, which included infratemporal fossa clearance in all 30 patients, followed by adjuvant therapy. The masseter was the most commonly involved masticatory muscle, and 24 patients had fewer than three involved structures. Free margins were obtained in 90.2% of cases; 41.5% of cases were node-positive. One hundred and four patients (84.6%) completed adjuvant treatment. The median follow-up was 42 months. For node-negative patients with T4a and T4b cancers, the 5-year overall survival was 59% and 50.2%, respectively (P= 0.62), and 5-year disease-free survival was 64.6% and 53.5%, respectively (P= 0.01). In conclusion, the select group of patients with T4b oral cancers and less than three masticatory space structures involved had comparable outcomes to those with T4a cancers after treatment with surgery and adjuvant radiotherapy.

Genetically detoxified pertussis toxin induces superior antigen specific CD4 T cell responses compared to chemically detoxified pertussis toxin

Pertussis is resurgent worldwide. Currently available acellular pertussis vaccines contain chemically detoxified pertussis toxin (PTc); a highly immunogenic genetically detoxified pertussis toxin (PTg) vaccine has been off the market for over a decade. We compared CD4⁺ T cell and B cell responses induced by genetically detoxified pertussis toxin (PTg) and chemically detoxified pertussis toxin (PTc) using naive human neonatal cells. Responses to novel adjuvants were also assessed. PTg induced significant antigen-specific CD4⁺ T cell activation and IL17 secretion than PTc. TLR agonist combinations improved PTg induced T cell-CD69 expression and IL17 secretion.

TLR agonist combinations that stimulate Th type I polarizing responses from human neonates

Each year millions of neonates die due to vaccine preventable infectious diseases. Our study seeks to develop novel neonatal vaccines and improve immunogenicity of early childhood vaccines by incorporating TLR agonist-adjuvant combinations that overcome the inherent neonatal Th2 bias and stimulate Th1 polarizing response from neonatal APCs. We systematically stimulated cord blood mononuclear cells with single and multiple combinations of TLR agonists and measured levels of IL-12p70, IFN-γ, IFN-α, IL-10, IL-13, TNF-α, IL-6 and IL-1β from cell culture supernatants. APC-specific surface expression levels of costimulatory markers CD40, CD83 and PD-L1 were assessed by flow cytometry. Whole blood assays were included to account for the effect of plasma inhibitory factors and APC intracellular TNF-α and IL-12p40 secretions were measured. We found robust Th1 polarizing IL-12p70, IFN-γ and IFN-α responses when cord blood APCs were stimulated with TLR agonist combinations that contained Poly I:C, Monophosphoryl Lipid A (MPLA) or R848. Addition of class A CpG oligonucleotide (ODN) to Th1 polarizing TLR agonist combinations significantly reduced cord blood IL-12p70 and IFN-γ levels and addition of a TLR2 agonist induced significantly high Th2 polarizing IL-13. Multi-TLR agonist combinations that included R848 induced lower inhibitory PD-L1 expression on cord blood classical dendritic cells than CpG ODN-containing combinations. Incorporation of combination adjuvants containing TLR3, TLR4 and TLR7/8 agonists to neonatal vaccines may be an effective strategy to overcome neonatal Th2 bias.

Prospective study of the innate cellular immune response in low vaccine responder children

We recently reported our findings from a longitudinal, prospective study where we identified 10% infants who were low vaccine responders (LVR) at age 9-12 mo following routine primary series vaccine schedule. We found multiple cellular deficiencies in LVR children, including low number of memory B cells, reduced polyclonal stimulation of naïve/memory T cell response and suboptimal APC response. These children outgrew their poor vaccine response by the time they received booster doses of vaccine. Studies in human infant innate immunity are rare because of the unique challenges in specimen collection. As innate immunity instructs adaptive immunity, we hypothesized that the primary immune defect lies with innate immunity and in this study we sought to determine the ontogeny of innate immune response in LVR children between 6 and 36 mo of age. Interestingly, suboptimal APC response observed in LVR children at 6-9 mo of age characterized by significantly ( P < 0.05) low basal MHC II expression, low R848 induced IRF7 fold change, as well as low IFN-α, IL-12p70 and IL-1β levels, came to parity with normal vaccine responders by 12-15 mo of age, suggesting that the observed immune deficiency in LVR children may be the result of delayed maturation of immune system.

Infants with low vaccine antibody responses have altered innate cytokine response

We recently identified a population of 10% of infants who respond with sub-protective antibody levels to most routine primary pediatric vaccinations due to altered innate and adaptive immune responses. We term these infants as low vaccine responders (LVRs). Here we report new data showing that TLR7/8 agonist - R848 stimulation of PBMCs of LVR infants elicit significantly lower IFN-α, IL-12p70 and IL-1β, while inducing higher levels of CCL5 (RANTES) compared to normal vaccine responder (NVR) infants.

Functional Immune Cell Differences Associated With Low Vaccine Responses in Infants

BACKGROUND

We sought to understand why some children respond poorly to vaccinations in the first year of life.

METHODS

A total of 499 children (6-36 months old) provided serum and peripheral blood mononuclear cell samples after their primary and booster vaccination. Vaccine antigen-specific antibody levels were analyzed with enzyme-linked immunosorbent assay, and frequency of memory B cells, functional T-cell responses, and antigen-presenting cell responses were assessed in peripheral blood mononuclear cell samples with flow cytometric analysis.

RESULTS

Eleven percent of children were low vaccine responders, defined a priori as those with subprotective immunoglobulin G antibody levels to ≥66% of vaccines tested. Low vaccine responders generated fewer memory B cells, had reduced activation by CD4(+) and CD8(+) T cells on polyclonal stimulation, and displayed lower major histocompatibility complex II expression by antigen-presenting cells.

CONCLUSIONS

We conclude that subprotective vaccine responses in infants are associated with a distinct immunologic profile.

Neonatal Vaccination: Challenges and Intervention Strategies

BACKGROUND

While vaccines have been tremendously successful in reducing the incidence of serious infectious diseases, newborns remain particularly vulnerable in the first few months of their life to life-threatening infections. A number of challenges exist to neonatal vaccination. However, recent advances in the understanding of neonatal immunology offer insights to overcome many of those challenges.

OBJECTIVE

This review will present an overview of the features of neonatal immunity which make vaccination difficult, survey the mechanisms of action of available vaccine adjuvants with respect to the unique features of neonatal immunity, and propose a possible mechanism contributing to the inability of neonates to generate protective immune responses to vaccines.

METHODS

We surveyed recent published findings on the challenges to neonatal vaccination and possible intervention strategies including the use of novel vaccine adjuvants to develop efficacious neonatal vaccines.

RESULTS

Challenges in the vaccination of neonates include interference from maternal antibody and excessive skewing towards Th2 immunity, which can be counteracted by the use of proper adjuvants.

CONCLUSION

Synergistic stimulation of multiple Toll-like receptors by incorporating well-defined agonist-adjuvant combinations to vaccines is a promising strategy to ensure a protective vaccine response in neonates.

Peripheral blood antigen presenting cell responses in otitis-prone and non-otitis-prone infants

Stringently defined otitis-prone (sOP) children represent a new classification of the otitis-prone condition. Previous studies showed dysfunction in Ab, B-cell memory and T-cell memory responses. We sought to determine whether there are defects in numbers, phenotype and/or function of professional APC in the peripheral blood of sOP infants. APC phenotypic counts, MHC II expression and intracellular cytokine levels were determined in response to TLR7/8 (R848) stimulation by flow cytometry. Innate immune mRNA expression was measured using RT-PCR and cytokines were measured using Luminex technology. Significant (P < 0.05) increases in the phenotypic counts of monocytes and conventional dendritic cells but not plasmacytoid DCs were observed in sOP compared with non-otitis-prone (NOP) age-matched infants. No significant differences in APC activation or function were observed. Expression of various TLRs, intracellular signaling molecules and downstream cytokines was also not found to be significantly different between sOP and NOP infants. Higher numbers of APCs in sOP infants suggest the possibility of a persistent mucosal inflammatory status. Transcriptional and cytokine profiles of PBMCs among sOP infants suggest their systemic innate responses are not different compared to NOP infants.

Dual orientation of the outer membrane lipoprotein Pal in Escherichia coli

Peptidoglycan associated lipoprotein (Pal) of Escherichia coli (E. coli) is a characteristic bacterial lipoprotein, with an N-terminal lipid moiety anchoring it to the outer membrane. Since its discovery over three decades ago, Pal has been well studied for its participation in the Tol-Pal complex which spans the periplasm and has been proposed to play important roles in bacterial survival, pathogenesis and virulence. Previous studies of Pal place the lipoprotein in the periplasm of E. coli, allowing it to interact with Tol proteins and the peptidoglycan layer. Here, we describe for the first time, a subpopulation of Pal which is present on the cell surface of E. coli. Flow cytometry and confocal microscopy detect anti-Pal antibodies on the surface of intact E. coli cells. Interestingly, Pal is surface exposed in an 'all or nothing' manner, such that most of the cells contain only internal Pal, with fewer cells ( < 20  %) exhibiting surface Pal.

Vγ2Vδ2 T cell Costimulation Increases NK cell Killing of Monocyte-derived Dendritic Cells

Interactions between NK and dendritic cells (DC) affect maturation and function of both cell populations, including NK killing of DC (editing) that is important for controlling the quality of immune responses. We also know that antigen-stimulated Vγ2Vδ2 T cells costimulate NK cells via 4-1BB to enhance killing of tumor cell lines but we do not know what regulates 4-1BB expression or whether other NK effector functions including DC killing, might also be influenced by NK:γδ T cell cross talk. Here we show that antigen-stimulated γδ T cells costimulate NK through ICOS:ICOSL and this signal increases NK killing of autologous DC. Effects of NK:γδ T cell co-culture, which could be reproduced with soluble ICOS-Fc fusion protein, included increased CD69 and 4-1BB expression, IFN-γ, TNF-α, MIP-1β, I-309, RANTES and sFasL production, as well as elevated mRNA levels for costimulatory receptors OX40 (TNFRSF4) and GITR (TNFRSF18). Thus, ICOS/ICOSL costimulation of NK by Vγ2Vδ2 T cells had broad effects on NK phenotype and effector functions. The NK γδ T cell cross talk links innate and antigen-specific lymphocyte responses in the control of cytotoxic effector function and dendritic cell killing. This article is protected by copyright. All rights reserved.

Immune responses in neonates

Neonates have little immunological memory and a developing immune system, which increases their vulnerability to infectious agents. Recent advances in the understanding of neonatal immunity indicate that both innate and adaptive responses are dependent on precursor frequency of lymphocytes, antigenic dose and mode of exposure. Studies in neonatal mouse models and human umbilical cord blood cells demonstrate the capability of neonatal immune cells to produce immune responses similar to adults in some aspects but not others. This review focuses mainly on the developmental and functional mechanisms of the human neonatal immune system. In particular, the mechanism of innate and adaptive immunity and the role of neutrophils, antigen presenting cells, differences in subclasses of T lymphocytes (Th1, Th2, Tregs) and B cells are discussed. In addition, we have included the recent developments in the neonatal mouse immune system. Understanding neonatal immunity is essential to development of therapeutic vaccines to combat newly emerging infectious agents.

Protection to respiratory challenge of Brucella abortus strain 2308 in the lung

Brucella is amongst the top 5 causes of zoonotic disease worldwide. Infection is through ingestion, inhalation or contact exposure. Brucella is characterized as a class B pathogen by Centers of Disease Control and Prevention (CDC). Currently, there are no efficacious vaccines available in people. Currently available USDA approved vaccines for animals include B. abortus strain RB51 and B. melitensis Rev1. Protection is mediated by a strong innate and CD4 Th1, CD8 Tc1 immune response. If protective vaccines can be developed, disease in people and animals can be controlled. While strain RB51 protects in cattle, and against intraperitoneal challenge in mice, it does not protect against respiratory challenge. Therefore, we assessed the efficacy of strain RB51 combined with different TLR agonists, and O-side chain from LPS, to enhance protection against respiratory challenge with strain 2308. We hypothesized that TLR agonists and O-side chain would enhance protection. Strains RB51 with TLR2 agonist, RB51 with TLR4 agonist and strain 19 provided significant protection in the lung. Protection using strain RB51 with TLR agonists was associated with increased IgG2a and IgG1 in the (bronchoalveolar lavage) BAL and serum, and increased IgA (serum). Splenocytes from strain RB51 with TLR2 vaccinated mice up-regulated antigen specific interferon-gamma and TNF-alpha production. Vaccination and challenge resulted in significant increases in activated dendritic cells (DCs), and increased CD4 and CD8 cells in the BAL. Overall, this study demonstrates the ability of TLR agonists 2 and 4 to up-regulate strain RB51 mediated protection in the lung to respiratory challenge against strain 2308.

Efficacy of vaccination strategies against intranasal challenge with Brucella abortus in BALB/c mice

Brucellosis is a zoonotic disease affecting 500,000 people worldwide annually. Inhalation of aerosol containing a pathogen is one of the major routes of disease transmission in humans. Currently there are no licensed human vaccines available. Brucella abortus strain RB51 is a USDA approved live attenuated vaccine against cattle brucellosis. In a mouse model, strain RB51 over-expressing superoxide dismutase (SOD) administered intraperitoneally (IP) has been shown to be more protective than strain RB51 against an IP challenge with B. abortus pathogenic strain 2308. However, there is lack of information on the ability of these vaccine strains to protect against intranasal challenge. With the long-term goal of developing a protective vaccine for animals and people against respiratory challenge of Brucella spp., we tested a number of different vaccination strategies against intranasal infection with strain 2308. We employed strains RB51 and RB51SOD to assess the efficacy of route, dose, and prime-boost strategies against strain 2308 challenge. Despite using multiple protocols to enhance mucosal and systemic protection, neither rough RB51 vaccine strains provided respiratory protection against intranasal pathogenic Brucella infection. However, intranasal (IN) administration of B. abortus vaccine strain 19 induced significant (p≤0.05) pulmonary clearance of strain 2308 upon IN challenge infection compared to saline. Further studies are necessary to address host-pathogen interaction in the lung microenvironment and elucidate immune mechanisms to enhance protection against aerosol infection.

Heat-killed and γ-irradiated Brucella strain RB51 stimulates enhanced dendritic cell activation, but not function compared with the virulent smooth strain 2308

Brucella spp. are Gram-negative, facultative intracellular bacterial pathogens that cause abortion in livestock and undulant fever in humans worldwide. Brucella abortus strain 2308 is a pathogenic strain that affects cattle and humans. Currently, there are no efficacious human vaccines available. However, B. abortus strain RB51, which is approved by the USDA, is a live-attenuated rough vaccine against bovine brucellosis. Live strain RB51 induces protection via CD4(+) and CD8(+) T-cell-mediated immunity. To generate an optimal T-cell response, strong innate immune responses by dendritic cells (DCs) are crucial. Because of safety concerns, the use of live vaccine strain RB51 in humans is limited. Therefore, in this study, we analyzed the differential ability of the same doses of live, heat-killed (HK) and γ-irradiated (IR) strain RB51 in inducing DC activation and function. Smooth strain 2308, live strain RB51 and lipopolysaccharide were used as controls. Studies using mouse bone marrow-derived DCs revealed that, irrespective of viability, strain RB51 induced greater DC activation than smooth strain 2308. Live strain RB51 induced significantly (P≤0.05) higher DC maturation than HK and IR strains, and only live strain RB51-infected DCs (at multiplicity of infection 1:100) induced significant (P≤0.05) tumor necrosis factor-α and interleukin-12 secretion.

The significance of TLRs in Brucella mediated dendritic cell activation in vitro and pulmonary clearance in vivo (42.16)

Brucellosis is a worldwide zoonoses affecting 500,000 people annually with no approved human vaccines available. Live attenuated B. abortus vaccine strain RB51 protects cattle through CD4 and CD8 T-cell mediated responses. However, there are concerns regarding its efficacy and use as a live vaccine in people. Therefore, identifying how Brucella vaccines stimulate innate and adaptive immunity is critical to enhancing vaccine efficacy. Brucella stimulate dendritic cells (DCs) through Toll-Like Receptors (TLRs) 2, 4 and 9. In this study, to identify how rough vaccine strains stimulate DC activation and function in vitro, we used vaccine strain RB51 versus pathogenic strain 2308 to stimulate bone marrow derived dendritic cells (BMDCs) from TLR2, 4 or 9 knockout (KO) and wild type BALB/c mice. Since inhalation of infected aerosols is one of the most common routes of exposure, in vivo clearance of strain RB51 compared to strain 2308 from intranasally (IN) infected TLR KO vs. control BALB/c mice was assessed. We determined that strain RB51 induced significant (p≤0.05) DC activation compared to strain 2308 which was TLR independent. However, strain RB51 induced TNF - α production was TLR2 and TLR9 dependent and IL-12 production was TLR2 and TLR4 dependent. TLR4 KO mice had significantly (p≤0.05) delayed pulmonary clearance of strain RB51 in vivo at day 14 post infection. Based on these data, future studies will focus on enhancing the protective ability of strain RB51.

Left over bowels: an unique complication in a surviving twin

Conjoint twins have always been a surgical challenge. The authors report an unusual finding in a surviving epigastric heteropagus twin. A 17 year old boy who underwent laparotomy for acute intestinal obstruction revealed a blind ending but complete duplication of the large bowel and an accessory liver in the falciform ligament, along with a separate gall bladder but with fused bile ducts. The findings suggest that the duplicated bowel loop and the accessory liver were remnants of the incomplete parasite twin, assimilated into the body of the autosite, which remained asymptomatic for 17 years. This case is being reported because of the uniqueness of the finding.

Evidence for overlapping substrate specificity between large neutral amino acid (LNAA) and dipeptide (hPEPT1) transporters for PD 158473, an NMDA antagonist

PURPOSE

The objective of this research was to investigate the substrate specificity of large neutral amino acid carrier (LNAA) and di/tripeptide (hPEPT1) transporters with respect to PD 158473, an NMDA antagonist.

METHODS

Cellular uptake studies were carried out using two types of Chinese Hamster Ovary (CHO). CHO-K1 cells represent the wild type with inherent large neutral amino acid (LNAA) activity. CHO-PEPT1 cells were generated by stable transfection of hPEPT1 gene into CHO cells. Therefore, these cells possess both LNAA activity and di/tripeptide transporter activities as a result of the transfection. Cellular uptake of PD 158473 was quantified using a HPLC method previously developed in our laboratory.

RESULTS

The utility of the CHO-PEPT1 cell model was demonstrated by determining the uptake kinetics of Gly-Sar, a prototypical dipeptide transporter substrate. Uptake kinetics of PD 158473 displayed two carrier-mediated transport components in CHO-PEPT1 cells, while in CHO-K1 cells the relationship was consistent with classic one component Michaelis-Menten kinetics. These results confirmed the affinity of PD 158473 for both LNAA and di/tripeptide transporters. Further, results from inhibition experiments using these two cell types indicate that the high affinity-low capacity system was the LNAA carrier and the low affinity-high capacity carrier was the di/tripeptide transporter.

CONCLUSIONS

This study demonstrates overlapping substrate specificity between LNAA carrier and di/tripeptide transporter (hPEPT1) for PD 158473, an amino acid analog. Establishing Structure Transport Relationship (STR) for this overlap will aid in a design strategy for increasing oral absorption or targeting specific drugs to selected tissues.

Automated sample preparation for drugs in plasma using a solid-phase extraction workstation

An automated solid-phase extraction workstation was used to develop, characterize and validate two separate HPLC methods for quantifying drugs in plasma. Method development was facilitated by workstation functions which allowed wash solvents of varying organic composition to be mixed and tested automatically. The precision estimates for the two methods were within 6.0 and 2.0% RSD across their respective calibration ranges. Accuracies for replicate determinations of quality controls were between -1.2 and +4.8 RE over ng ml-1 calibration ranges, respectively. Optimized recoveries were quantitative and were generally greater than 90% for the four analytes tested, and depended to a great extent, as expected, on the composition of the wash solvent. Sample throughput benchmarks for the two methods ranged from 3 to 10 min per sample, depending on the extent of air drying used. Because of parallel sample processing, 60 samples could be extracted in as little as 17 min.

Development and validation of an ion-pair reversed-phase high-performance liquid chromatographic method for the separation of phosphonodipeptides

The objective of this research was to develop a rapid, sensitive and reliable method for the separation of phosphonodipeptide prodrugs and parent compounds to facilitate the evaluation of cell permeation using in vitro cell culture models. Separation was accomplished isocratically within 10.0 min using a C18 (150x4.6 mm I.D., 3 microm) reversed-phase column. The mobile phase consisted of 5 mM tetrahexyl ammonium (ion-pair reagent) in 0.02 M phosphate buffer pH 6.5-acetonitrile (48.5:51.5, v/v). The flow-rate was 1.1 ml/min with detection at 221 nm. The standard curves were linear (r2>0.999) over the concentration range 1-100 microM. The method was reliable and reproducible, with the limit of quantitation being 1 microM (25 ng on column).

High-performance liquid chromatographic assay for Melanotan-1 ([Nle4-DPhe7]alpha-melanocyte-stimulating hormone) in biological matrices

The overall objective of this research was to develop a sensitive, specific, and stability-indicating HPLC assay for the determination of the [Nle4-DPhe7]alpha-melanocyte-stimulating hormone analog known as Melanotan-1 (MT-1) in biological matrices, i.e., cell culture transport media and human plasma. Separation was accomplished isocratically within 8.0 min using a C8 reversed-phase column. The mobile phase consisted of 0.1 M phosphate buffer-acetonitrile (80:20, v/v) with 18 microliters/l triethylamine at pH 2.50. The flow-rate was 1 ml/min with detection at 214 nm. Standard curves (n = 5) were linear over the concentration range 100-1000 ng/ml. The precision, accuracy, intra- and inter-day variations were good with C.V.s typically within 8.7% for concentrations greater than 100 ng/ml. This method was applied to a study of the transport of MT-1 in the Caco-2 cell monolayer model.

Enhancement of calcium transport in the Caco-2 cell monolayer model

The overall objective of this research was to identify enhancers of calcium transport using an in-vitro Caco-2 cell monolayer model. The enhancers studied were medium-chain triglycerides (MCT) and acylcarnitines (AC). The extent of cell damage associated with the use of these enhancers was determined by monitoring the release of cellular lactate dehydrogenase (LDH). The effect of chain-length and concentration dependence of these agents on enhancement were also determined. The effects of ACs were found to be superior to those of MCTs. However, the ACs elicited a greater release of LDH than the MCTs. The possible mechanisms of enhancer-mediated increase in calcium transport and the potential significance of this study with regard to the prevention of osteoporosis are discussed.

Mechanisms of acylcarnitine-mediated enhancement of calcium transport in the Caco-2 cell monolayer model

The overall objective of this study was to determine the mechanisms of acylcarnitine-mediated enhancement of calcium transport across Caco-2 cells. The different mechanisms of enhancement postulated are (a) loosening of tight junctions, thereby promoting paracellular transport; (b) opening of calcium channels, thus increasing calcium entry; and (c) stimulation of the basolateral Ca-ATPase pump, thereby aiding calcium extrusion. Although the existence of calcium channels and the reversal of verapamil-mediated inhibition of calcium uptake by acylcarnitines were demonstrated for the first time in Caco-2 cells, the channels do not appear to be a major contributing factor to the enhancement of calcium transport by acylcarnitines. Calmidazolium, a potent Ca-ATPase pump inhibitor in tissues such as rat intestinal segments, failed to inhibit this pump in Caco-2 cells. Thus, the predominant mechanism of enhancement of calcium transport by acylcarnitines in the Caco-2 model appears to be via promotion of paracellular transport.

Neuroblastoma with testicular metastasis. Review of literature and report of a case

Eventhough neuroblastoma presents with wide spread tumour dissemination, metastasis to testes had rarely been reported. We report a case of Stage IV neuroblastoma who developed metastasis to both testes. He had massive infra-diaphragmatic disease with involvement of left supraclavicular lymph node at presentation. Treatment received by him was not adequate and five months later he developed metastasis to both testes. Hematogenous spread might have been the possibility in this case.

Midline cleft of lower lip with cleft of the mandible and midline dermoid in the neck

A female infant presented with a midline cleft of the mandible and a midline dermoid in the neck. Midline clefts are rare craniofacial clefts. Midline mandibular clefts can be associated with midline cleft of upper lip and a dermoid of nose. But a midline mandibular cleft with a midline dermoid in the neck has not been reported before.

Hepatoblastoma in siblings

Two infants, a brother and sister, with hepatoblastoma of the right lobe of the liver were treated and are alive and lead normal lives. Only three other familial occurrences of this tumor have so far been documented.

Unusual presentation of patent vitello intestinal duct with round worms emerging from the umbilicus

Patient vitello intestinal duct (VID) is not an uncommon anomaly in children. It usually presents with fecal discharge from the umbilicus. Round worm infestation is very common in Indian children, but an association of patent VID and ascariasis, presenting as round worms emerging from the umbilicus, is unique and has not been previously reported in the literature. We present such a case in a 2-year-old boy who presented with a history of round worms coming out through the umbilicus. It was provisionally diagnosed to be a case of patent VID, which was proven correct on laparotomy.

Intestinal complications of round worms in children

One hundred forty-two patients with surgical complications of Ascaris lumbricoides were treated in our hospital over a period of 5 years. Included were 120 patients with subacute intestinal obstruction that were treated conservatively, and 22 patients with acute intestinal obstruction that required surgical intervention. Four of the 22 patients that were operated on died following various postoperative complications. However, there were no deaths among those presenting with subacute obstruction. In our experience, early recognition of the condition avoided serious complications and morbidity.

An unusual case of caudal duplication

A male infant presented with two well-formed lower limbs and pelvis with external male genitalia attached to the thorax at the xiphisternum. The infant also had exomphalos major and talipes equinovarus deformity of the right foot. Surgical correction was done without any difficulty. The case is unusual, and such an abnormality has not been reported before.

Surgical Repair in Aplasia Cutis Congenita

A 20 day old child had aplasia cutis congenita manifesting as a linear-buua since birth on the scalp, involving the skin, subcutaneous tissue and the underlying bone. lle bulla contained CSF. A prompt surgical repair of the case was undertaken.