Increasing COVID-19 Vaccination in the United States: Projected Impact on Cases, Hospitalizations, and Deaths by Age and Racial Group

Objectives

Minority populations in the United States face a disproportionate burden of illness from COVID-19 infection and have lower vaccination rates compared with other groups. This study estimated the equity implications of increased COVID-19 vaccination in the United States, with a focus on the number of cases, hospitalizations, and deaths avoided.

Study design

This was an observational real-world modeling study.

Methods

Data from the Centers for Disease Control and Prevention (CDC) were used to identify the remaining unvaccinated US population by county, age, and race as of October 22, 2021. The number of COVID-19 cases, hospitalizations, and deaths avoided were calculated based on case incidence and death data from the CDC, along with data on race- and age-specific hospitalization multipliers, under a scenario in which half of the remaining unvaccinated population per county, race, and age group obtained a full vaccine regimen.

Results

Vaccinating half of the remaining unvaccinated population in each age and race subgroup within counties would result in an estimated 22.09 million COVID-19 cases avoided, 1.38 million hospitalizations avoided, and 150,000 deaths avoided over 12 months. Some minority groups, particularly Black and Hispanic/Latino populations, were projected to experience substantial benefits from increased vaccination rates as they face both lower vaccination rates and worse outcomes if infected with COVID-19.

Conclusions

Increasing COVID-19 vaccination in the United States not only benefits the population as a whole but also serves as a potentially useful lever to reduce the disproportionate burden of COVID-19 illness among minority populations.

Abstract PO-100: Association of B7-H3 expression with racial ancestry, immune cell density and AR activation in prostate cancer

Background: B7-H3 (CD276, PD-L3) is an immunomodulatory molecule highly expressed in prostate cancer and belonging to the B7 superfamily that also includes PD-L1 (B7-H1). Immunotherapies (antibodies, antibody-drug conjugates, and CAR-T cells) targeting B7-H3 are currently in clinical trials; thus elucidating the clinical, molecular and tumor immune microenvironment correlates of B7-H3 expression may help to guide trial design and interpretation. Methods: We developed an automated, clinical-grade immunohistochemistry assay to digitally quantify B7-H3 protein expression across two racially diverse cohorts of primary prostate cancer (including one with previously reported transcriptomic data), a set of prostatic neuroendocrine small cell carcinoma, and pre- and post-treatment tumor tissues from a trial of intensive neoadjuvant hormonal therapy. Results: B7-H3 protein expression is significantly lower in self-identified Black patients and inversely correlates with percent African ancestry by ancestry-informative markers. This association with race is independent of the significant association of B7-H3 expression with ERG/ETS and PTEN status. CD276 mRNA level, but not B7-H3 protein expression, is significantly correlated with regulatory (FOXP3+) T-cell density. Finally, androgen receptor activity (AR-A) scores are significantly correlated with CD276 mRNA expression, and neoadjuvant intensive hormonal therapy is associated with a significant decrease in B7-H3 protein expression. Conclusion: These data underscore the importance of studying racially and molecularly diverse prostate cancer cohorts in the era of immunotherapy. Our study is among the first to use genetic ancestry markers to add to emerging evidence that prostate tumors from men of African ancestry may have a distinct immune milieu associated with B7-H3 expression.

Citation Format: Adrianna A. Mendes, Jiayun Lu, Harsimar B Kaur, Siqun Zheng, Jianfeng Xu, Edward M. Schaeffer, Karen S. Sfanos, Janielle Maynard, Ashley E. Ross, Steven P. Balk, Mary-Ellen Taplin, Emmanuel S. Antonarakis, Corinne E. Joshu, Eugene Shenderov, Tamara L. Lotan. Association of B7-H3 expression with racial ancestry, immune cell density and AR activation in prostate cancer [abstract]. In: Proceedings of the AACR Virtual Conference: 14th AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2021 Oct 6-8. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2022;31(1 Suppl):Abstract nr PO-100.

Oxidative Stress and Cardiovascular Risk in Type 1 Diabetes Mellitus: Insights From the DCCT/EDIC Study

Background

Hyperglycemia leading to increased oxidative stress is implicated in the increased risk for the development of macrovascular and microvascular complications in patients with type 1 diabetes mellitus.

Methods and Results

A random subcohort of 349 participants was selected from the DCCT / EDIC (Diabetes Control and Complications Trial/Epidemiology of Diabetes Interventions and Complications) cohort. This included 320 controls and 29 cardiovascular disease cases that were augmented with 98 additional known cases to yield a case cohort of 447 participants (320 controls, 127 cases). Biosamples from DCCT baseline, year 1, and closeout of DCCT , and 1 to 2 years post‐ DCCT ( EDIC years 1 and 2) were measured for markers of oxidative stress, including plasma myeloperoxidase, paraoxonase activity, urinary F 2α isoprostanes, and its metabolite, 2,3 dinor‐8 iso prostaglandin F 2α . Following adjustment for glycated hemoblobin and weighting the observations inversely proportional to the sampling selection probabilities, higher paraoxonase activity, reflective of antioxidant activity, and 2,3 dinor‐8 iso prostaglandin F 2α , an oxidative marker, were significantly associated with lower risk of cardiovascular disease (−4.5% risk for 10% higher paraoxonase, P <0.003; −5.3% risk for 10% higher 2,3 dinor‐8 iso prostaglandin F 2α , P =0.0092). In contrast, the oxidative markers myeloperoxidase and F 2α isoprostanes were not significantly associated with cardiovascular disease after adjustment for glycated hemoblobin. There were no significant differences between DCCT intensive and conventional treatment groups in the change in all biomarkers across time segments.

Conclusions

Heightened antioxidant activity (rather than diminished oxidative stress markers) is associated with lower cardiovascular disease risk in type 1 diabetes mellitus, but these biomarkers did not change over time with intensification of glycemic control.

Clinical Trial Registration

URL : https://www.clinicaltrials.gov . Unique identifiers: NCT 00360815 and NCT 00360893.

Improving Immunization Coverage through Budgeted Microplans and Sub-national Performance Agreements: Early Experience from Cambodia

In recent years, Cambodia has demonstrated significant success in specific aspects of immunization with gains through campaign efforts in measles control and polio eradication. In contrast, routine immunization rates have failed to improve over the last five years. In response, the National Immunization Program of the Ministry of Health developed a coverage improvement planning (CIP) process. This paper describes the CIP process in Cambodia, including identified barriers to and strategies for improving coverage. Immunization coverage rose in 8 of 10 pilot districts in the year following the introduction of CIP in 2003. The mean increase in DPT3 coverage across pilot districts on an annual basis was 16%, which provides encouraging early evidence for the effectiveness of the intervention. Factors associated with success in coverage improvement included: (1) development of a needs-based micro-plan, (2) application of performance-based contracting between levels of management, (3) investment in social mobilization, (4) securing finance for health outreach programs and (5) strengthened monitoring systems. Lessons learned will guide program expansion to improve immunization coverage nationally.

Interictal psychosis following temporal lobe surgery: dentate gyrus pathology

BACKGROUND

De novo interictal psychosis, albeit uncommon, can develop in patients following temporal lobe surgery for epilepsy. Pathological alterations of the dentate gyrus, including cytoarchitectural changes, immaturity and axonal reorganization that occur in epilepsy, may also underpin co-morbid psychiatric disorders. Our aim was to study candidate pathways that may be associated with the development of interictal psychosis post-operatively in patients with hippocampal sclerosis (HS).

METHOD

A total of 11 patients with HS who developed interictal psychosis (HS-P) post-operatively were compared with a matched surgical HS group without psychosis (HS-NP). Resected tissues were investigated for the extent of granule cell dispersion, mossy fibre sprouting and calbindin expression in the granule cells. We quantified doublecortin, mini-chromosome maintenance protein 2 (MCM2) and reelin-expressing neuronal populations in the dentate gyrus as well as the distribution of cannabinoid type 1 receptor (CBR1).

RESULTS

The patterns of neuronal loss and gliosis were similar in both groups. HS-P patients demonstrated less mossy fibre sprouting and granule cell dispersion (p < 0.01) and more frequent reduction in calbindin expression in granule cells. There were no group differences in the densities of immature MCM2, doublecortin and reelin-positive cells. CBR1 labelling was significantly lower in Cornu ammonis area CA4 relative to other subfields (p < 0.01); although reduced staining in all hippocampal regions was noted in HS-P compared with HS-NP patients, the differences were not statistically significant.

CONCLUSIONS

The alterations in dentate gyrus pathology found in HS-P patients could indicate underlying differences in the cellular response to seizures. These mechanisms may predispose to the development of psychosis in epilepsy and warrant further investigation.

The role of symbiont genetic distance and potential adaptability in host preference towards Pseudonocardia symbionts in Acromyrmex leaf-cutting ants

Fungus-growing ants display symbiont preference in behavioral assays, both towards the fungus they cultivate for food and Actinobacteria they maintain on their cuticle for antibiotic production against parasites. These Actinobacteria, genus Pseudonocardia Henssen (Pseudonocardiacea: Actinomycetales), help defend the ants' fungal mutualist from specialized parasites. In Acromyrmex Mayr (Hymenoptera: Formicidae) leaf-cutting ants, individual colonies maintain either a single or a few strains of Pseudonocardia, and the symbiont is primarily vertically transmitted between generations by colony-founding queens. A recent report found that Acromyrmex workers are able to differentiate between their native Pseudonocardia strain and non-native strains isolated from sympatric or allopatric Acromyrmex species, and show preference for their native strain. Here we explore worker preference when presented with two non-native strains, elucidating the role of genetic distance on preference between strains and Pseudonocardia origin. Our findings suggest that ants tend to prefer bacteria more closely related to their native bacterium and that genetic similarity is probably more important than whether symbionts are ant-associated or free-living. Preliminary findings suggest that when continued exposure to a novel Pseudonocardia strain occurs, ant symbiont preference is potentially adaptable, with colonies apparently being able to alter symbiont preference over time. These findings are discussed in relation to the role of adaptive recognition, potential ecological flexibility in symbiont preference, and more broadly, in relation to self versus non-self recognition.

Vector prime protein boost vaccination in the setting of myeloablative-induced lymphopenia suppresses growth of leukemia and solid tumors

We have developed a vaccine, which is designed to induce tumor-associated antigen (TAA)-specific T cells and antibodies in the setting of profound lymphopenia induced by myeloablative therapy and T-cell-depleted bone marrow transplantation. Test mice were injected subcutaneously (sc) with the 32DP210Bcr-Abl cell line, which is positive for the p210Bcr-Abl protein (Group 1). In Group 2, 7 days after injection of the 32DP210Bcr-Abl positive cell line, the mice received 900 cGy total body irradiation (TBI) followed in 1 h by the intravenous infusion of 10 million T-cell-depleted syngeneic bone marrow cells (TCDBMT) (Group 2). The leukemia-bearing group received an intravenous injection of 10 million spleen cells (donor lymphocyte infusions) from unvaccinated (Group 3) and TAA/ecdCD40L-vaccinated (Group 4) syngeneic mice 3 days after completion of the TBI and TCDBMT. Groups 3 and 4 mice received three additional sc vaccinations at 7-day intervals with the TAA/ecdCD40L vaccine, in which the TAA was taken from the junctional peptide of the P210bcr-Abl protein. The survival of Groups 3 and 4 mice was significantly longer than that in Groups 1 and 2 mice. Vaccinated mice from Group 4, which developed complete responses, survived up to 350 days post-injection of the leukemia cells without any evidence of leukemia regrowth.

Targeting of chemotherapy to Tie-2-receptor positive angiogenic endothelial cells of tumor vasculature

Abstract #902

Background: There are at least three types of cells in tumor tissue which express the Tie2 receptor (Tie2R): dividing vascular endothelial cells (TVECs), Tie2R-expressing monocytes (TEMs) and Tie2R-expressing mesenchymal progenitor cells (TMPCs).&#x2028; &#x2028; We tested if the targeting of chemotherapy to these classes of Tie2R positive cells could suppress tumor cell growth.&#x2028; Material and Methods: We constructed replication incompetent adenoviral vectors carrying the cytosine deaminase (CD) suicide gene driven by the mouse Tie2R transcriptional promoter and enhancer sequences. In these viruses, we inserted an RGD-4C peptide into the HI loop of the fiber knob domain of the vector to increase its transduction efficiency in TVECs. At the same time, we added two mutations (S408E and P409A) in the AB loop of the fiber, which ablated the CAR-binding ability of the vector. The resulting vector was named AdTie2RCD(MRGD).&#x2028; Results: In vitro viral infection assays involving the human umbilical vein endothelial cells (HUVECs) showed that the RGD-modified vectors have a higher transduction efficiency as compared with their adenoviral vector counterparts which have a wild type fiber protein. Mice carrying the rat Her-2-Neu positive N202 mouse breast cancer cells and the mouse B16 melanoma cells were treated with intravenous injections of Hetastarch and the AdTie2RCD(MRGD) vector followed by intraperitoneal injections of 5-Fluorocytosine (5-FC). The Hetastarch was given before the intraveinous infusion of the adenoviral vector in order to reduce the uptake of the adenoviral vector by the reticuloendothelial cell system. The Tie2R targeted chemotherapy sensitization vectors induced greater degrees of suppression of tumor cell growth than did the control group, achieved the similar treatment effect to its CMV promoter counterpart, but with less side effect.&#x2028; &#x2028; Histological analysis showed that these vectors specifically targeted the TVECs, TEMs and TMPCs through which they may have exerted cytotoxic effects in the presence of 5-FC on the tumor cells.&#x2028; Discussion: Our results showed that N202 breast cancer cell line is more responsive to the Tie2R-targeting therapy compared to B16 mouse melanoma cell line and the Tie2R-directed anti-angiogenic therapy deserves further study, in combination with other types of therapy to pave the way for future clinic trails.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 902.

Inherited predisposition to colorectal adenomas caused by multiple rare alleles of MUTYH but not OGG1, NUDT1, NTH1 or NEIL 1, 2 or 3

BACKGROUND

MUTYH-associated polyposis (MAP) is a recessive trait characterised by multiple colorectal adenomas and a high risk of colorectal cancer. MUTYH functions in the DNA base excision repair pathway and has a key role in the repair of oxidative DNA damage.

OBJECTIVES

To assess the contribution of inherited variants in genes involved in base excision repair and oxidative DNA damage including MUTYH, OGG1, NEIL1, NEIL2, NEIL3, NUDT1 and NTH1 to the multiple colorectal adenoma phenotype.

METHODS

Inherited variants of MUTYH, OGG1, NEIL1, NEIL2, NEIL3, NUDT1 and NTH1 were sought in 167 unrelated patients with multiple colorectal adenomas whose family histories were consistent with recessive inheritance. These variants were also characterised in approximately 300 population controls.

RESULTS

Thirty-three patients (20%) and no controls were MUTYH homozygotes or compound heterozygotes (ie, carried two mutations) and therefore had MAP. Eight different pathogenic MUTYH mutations were identified, of which four were novel. MAP cases had significantly more adenomas than non-MAP cases (p = 0.0009; exact test for trends in proportions) and presented earlier (p = 0.013; analysis of variance). Twenty-four protein-altering variants were identified upon screening of OGG1, NEIL1, NEIL2, NEIL3, NUDT1 and NTH1. However, all combinations of two (or more) variants that were identified at an individual locus in patients were also seen in controls, and no variants were significantly over-represented (or under-represented) in cases.

CONCLUSION

Multiple rare alleles of MUTYH are associated with autosomal recessive MAP, while OGG1, NEIL1, NEIL2, NEIL3, NUDT1 and NTH1 do not contribute significantly to autosomal recessive polyposis.

Donor lymphocyte infusions from Ad-sig-TAA/ecdCD40L vector prime-TAA/ecdCD40L protein boost (VPP) vaccinated allodonors decrease tumor cell growth post allograft

3071

Background: Individuals of advanced chronological age exhibit an impaired immune response to vaccines. This may be due to a reduction in the ratio of antigen naïve/memory CD4 and CD8 T cells and acquisition of functional defects in activated “helper” CD4 T cells (eg diminished CD40 ligand (CD40L) expression) during the aging process. Methods: In order to circumvent this defective response to vaccines in individuals in the fifth and sixth decades of life, our laboratory has developed an adenoviral vector (Ad-sig- TAA/ecdCD40L) vaccine which is designed for the in vivo target associated antigen (TAA) loading and activation of dendritic cells (DCs), and to overcome the absence of CD40L expression in activated CD4 helper T cells in older individuals. Results: The subcutaneous (sc) injection of this vector leads to the release of a fusion protein composed of a TAA linked to the extracellular domain (ecd) of the CD40 ligand (CD40L), which binds to the CD40 receptor on DCs, activates the DCs, and leads to the presentation of TAA fragments on Class I MHC. Two sc injections of the TAA/ecdCD40L protein as a booster following the sc administration of the Ad-sig-TAA/ecdCD40L vector (VPP) expands the magnitude of the cellular and humoral immune response induced by the vector in 18 month old aged mice as well as in younger mice. This vaccine decreased levels of negative regulatory CD4 FOXP3 T cells in tumor nodules. We administered TBI and an allogeneic stem cell transplant 7 days post sc injection of the E7 positive TC-1 cells. DLI from an Ad-sig-E7/ecdCD40L vector prime-E7/ecdCD40L protein boost vaccinated donor were injected iv 3 days post transplant, and a single E7/ecdCD40L protein boost sc vaccination one week thereafter. We found that the growth rate of the E7 positive TC-1 tumor cells post allograft was less in the vaccinated than in the control (injection of tumor cells followed in 7 days by TBI), or the animals in which the allograft recipient was vaccinated without DLI. Conclusions: Thus, the use of DLI from VPP vaccinated allodonors decreased tumor cell growth post allograft.

No significant financial relationships to disclose.

Mapping of angiogenic markers for targeting of vectors to tumor vascular endothelial cells

The vasculature of mouse breast tumor spheroids grown on mammary fat pad tissue in an intravital microscopy (IVM) viewing chamber was shown to derive from infiltrating angiogenic mammary vessels. The receptors tissue factor (TF), alpha V beta 3 integrin and Tie-2 were expressed on the vascular endothelium in the periphery but not in the center of the tumor spheroids nor in the mammary tissue nor in smooth muscle tissue, whereas Tie-1 and PCAM-1 were expressed extensively in the entire tumor and in the vascular endothelium of the entire tumor nodule and in normal mammary tissue. TF is a specific target for adenoviral vector-mediated cancer immunotherapy. Subcutaneous injection of the AdfVII/IgG(1)Fc vector leads to the release into the system circulation of a fVII/IgG(1)Fc immunoconjugate molecule that binds specifically and tightly to TF on vascular endothelial cells and tumor cells, activating a cytolytic immune response against the targeted cells. We show that a single administration of the AdfVII/IgG(1)Fc vector destroys the peripheral but not the central vasculature of a tumor spheroid, causing partial tumor regression; additional administrations prevent regeneration of the peripheral vasculature and regrowth of the tumor. These findings indicate that a critical parameter for optimizing tumor damage is the schedule for successive administrations of the AdfVII/IgG(1)Fc, which should coincide with the regeneration of the peripheral vasculature and continue until the tumor is destroyed.

Vaccine for prevention of breast cancer

2580

Background: Women with high risk breast cancer still succumb to their disease despite existing programs of adjuvant therapy. Thus, new approaches for adjuvant therapy are needed. Her-2-Neu overexpression on a breast cancer cells correlates with recurrence, metastasis and resistance to chemotherapy and radiation therapy. The immune response is tolerant of tumor associated antigens (TAA) like Her-2-Neu since they have been present on epithelial cells since birth. The immune response to vaccines in women with breast cancer is limited by the diminished number of CD4 and CD8 T cells and qualitative defects of CD4 cells in individuals above the age of 50. Methods: The following strains of mice were vaccinated: 6–8 week old hMUC-1.Tg mice, and rH2N.Tg mice, as well as 18 month and 2 month old C57BL/6J mice, by injecting subcutaneously the Ad-sig-TAA/ecdCD40L vector prime followed by sc injections of the TAA/ecdCD40L protein boost. Results: Vaccination of 18 month old mice with the Ad-sig-TAA/ecdCD40L vector prime protein boost produce regressions of TAA positive sc tumor and a 5 fold increase in antigen specific spleen cells, a 10X increase in subcutaneous tumor nodules of antigen specific effector CD8 T cells by tetramers, and a 2X decrease of CD4+CD25+FOXP3+ cells. Vaccination of rH2N.Tg mice starting at 6 weeks with the Ad-sig-rH2N/ecdCD40L vector prime/protein boost prevented the development of breast cancer in 50% of the mice. The Ad-sig-hMUC-1/ecdCD40L vector prime/ hMUC-1/ecdCD40L protein boost induced hMUC-1 specific antibodies in hMUC-1.Tg mice which bound to human breast cancer specimens. The rH2N/ecdCD40L vector prime/protein boost vaccine suppressed growth of rH2N positive tumor cells and this effect was potentiated by concomitant administration of chemotherapy. Conclusions: These results suggest that the Ad-sig-TAA/ecdCD40L platform can be used to suppress the growth of existing breast cancer even in old mice and prevent the development of breast cancer. We are preparing a phase I clinical trial of this approach in the setting of breast cancer patients who have failed first line adjuvant therapy. In this trial, the vaccine will be added to established salvage therapy and both in vivo evaluations of tumor response, in vitro assays of immune response and toxicity will be measured.

No significant financial relationships to disclose.

Tumor-specific therapeutic effect induced by an oncolytic adenoviral vector containing heat shock protein 70 and prodrug activation genes

We constructed a melanoma-specific oncolytic adenoviral vector Ad.MCDIRESE1.71Hsp3, in which the cytosine deaminase and adenoviral E1A genes linked by the IRES sequence were under the control of a mouse tyrosinase enhancer/promoter transcriptional element in the E1 region of the vector. We also inserted the human heat shock protein 70 (Hsp70) gene driven by the cytomegalovirus promoter into the E3 region of this vector. The RGD-4C peptide was inserted into the HI loop of the fiber knob domain of the Ad.MCDIRESE1.71Hsp3 vector to increase the transduction efficiency of this vector to tumor cells. The Ad.MCDIRESE1.71Hsp3 vector replicates specifically in melanoma cells, and it has a melanoma-specific cytotoxic effect in the presence of 5-fluorocytosine in vitro and in vivo. Moreover, the in vivo killing of tumor cells associated with the overexpression of Hsp70 generated by the intratumoral injection of the Ad.MCDIRESE1.71Hsp3 vector into established subcutaneous tumors can lead to the suppression of tumor growth and potent melanoma-specific systemic immune responses.

Engineering conditionally replication-competent adenoviral vectors carrying the cytosine deaminase gene increases the infectivity and therapeutic effect for breast cancer gene therapy

We constructed a conditionally replication-competent adenoviral vector Ad.Lp-CD-IRES-E1A(control) in which the expression of both the prodrug-activating cytosine deaminase gene and the viral replication E1A gene were driven by the L-plastin tumor-specific promoter. In order to overcome the low infectivity of the adenoviral vectors for breast cancer cells, and to increase the safety and efficacy for cancer gene therapy, this vector was further modified on a transductional level by simultaneously ablating the native tropism of the vector to the primary CAR receptor and inserting a RGD-4C peptide into the HI loop of the fiber, which allows the vector to use the alphavbeta3 and alphavbeta5 receptors as alternative receptors. The resulting vector was named Ad.Lp-CD-IRES-E1A(MRGD). The transduction efficiency of the vector for breast cancer cell lines which have low expression level of CAR was increased both in vitro and in vivo. The Ad.Lp-CD-IRES-E1A(MRGD) vector produces a higher vector particle yield and a greater cytotoxic effect in tumor cells which have a low expression level of CAR, than did the Ad.Lp-CD-IRES-E1A(control) vector. Intratumoral injection of the Ad.Lp-CD-IRES-E1A(MRGD) vector following the intraperitoneal injection of 5FC into xenotransplanted human breast cancer cell lines which have low expression level of CAR led to greater degree of tumor regression in vivo than did the intratumoral injection of control adenoviral vectors not so modified.

Management systems response to improving immunization coverage in developing countries: a case study from Cambodia

INTRODUCTION

In contrast to the initial success following the establishment of the National Immunization Program (NIP) in Cambodia in 1986, infant vaccination coverage rates against the six expanded program immunization diseases have not improved since 1995. In response, the NIP of the Ministry of Health has undertaken a series of institutional initiatives to address the problem of static or declining rates of coverage. The aim of this paper is to describe and assess management strategies undertaken by the NIP in Cambodia in support of improved immunization coverage.

METHODS

Sources of information used in preparing this report include international literature, national coverage and surveillance data, government policy documentation, information generated by national strategic planning and health centre microplanning processes, a functional analysis of human resources, and data quality audits.

RESULTS

The NIP has implemented planning, organizational development and human resource development responses to the problem of low coverage. These have included: integration of the nip strategic and operational plans into the health sector plan; strengthening of needs-based microplanning; establishment of a national monitoring and management support strategy; and the introduction of performance-based agreements between levels of government for improved immunization coverage.

CONCLUSIONS

Our analysis of these findings, in particular of the international literature, suggests that NIP's responses have been appropriate, and that the development of NIP management systems and capacity will increase the likelihood for sustained immunization coverage gains within a reform environment of health system decentralization. In 2003, there are early signs that the reform processes undertaken by the NIP have resulted in improved immunization coverage in targeted areas, and this should place the national program in a stronger position to lift immunization coverage in 2004.

A technique for the determination of 18O/16O and 17O/16O isotopic ratios in water from small liquid and solid samples

We have developed a new technique in which a solid reagent, cobalt(III) fluoride, is used to prepare oxygen gas for isotope ratio measurement from water derived either from direct injection or from the pyrolysis of solid samples. The technique uses continuous flow, isotope ratio monitoring, gas chromatography/mass spectrometry (irmGC/MS) to measure the delta18O and delta17O of the oxygen gas. Water from appropriate samples is evolved by a procedure of stepped pyrolysis (0-1000 degrees C, typically in 50 degrees C increments) under a flowing stream of helium carrier gas. The method has considerable advantages over others used for water analysis in that it is quick; requires only small samples, typically 1-50 mg of whole rock samples (corresponding to approximately 0.2 micromol of H2O); and the reagent is easy and safe to handle. Reproducibility in isotope ratio measurement obtained from pyrolysis of samples of a terrestrial solid standard are delta18O +/- 0.54, delta17O +/- 0.33, and delta17O +/- 0.10/1000, 1sigma in all cases. The technique was developed primarily for the analysis of meteorites, and the efficiency of the method is illustrated herein by results from water standards, solid reference materials, and a sample of the Murchison CM2 meteorite.

Antibody engineering

Antibodies are unique in their high affinity and specificity for a binding partner, a quality that has made them one of the most useful molecules for biotechnology and biomedical applications. The field of antibody engineering has changed rapidly in the past 10 years, fueled by novel technologies for the in vitro isolation of antibodies from combinatorial libraries and their functional expression in bacteria. This review presents an overview of the methods available for the de novo generation of human antibodies, for engineering antibodies with increased antigen affinity, and for the production of antibody fragments. Select applications of recombinant antibodies are also presented.

Pathological mutations in TSC1 and TSC2 disrupt the interaction between hamartin and tuberin

Critical functions of hamartin and tuberin, encoded by the TSC1 and TSC2 genes, are likely to be closely linked. The proteins interact directly with one another and mutations affecting either gene result in the tuberous sclerosis phenotype. However, the regions of hamartin and tuberin that interact have not been well defined, and the relationship between their interaction and the pathogenesis of tuberous sclerosis has not been explored. To address these issues a series of hamartin and tuberin constructs were used to assay for interaction in the yeast two-hybrid system. Hamartin (amino acids 302-430) and tuberin (amino acids 1-418) interacted strongly with one another. A region of tuberin encoding a putative coiled-coil (amino acids 346-371) was necessary but not sufficient to mediate the interaction with hamartin, as more N-terminal residues were also required. A region of hamartin (amino acids 719-998) predicted to encode coiled-coils was capable of oligermerization but was not important for the interaction with tuberin. Subtle, non-truncating mutations identified in patients with tuberous sclerosis and located within the putative binding regions of hamartin (N198_F199delinsI;593-595delACT) or tuberin (G294E and I365del), abolished or dramatically reduced interaction of the proteins as assessed by yeast two-hybrid assays and by co-immunoprecipitation of the full-length proteins from Cos7 cells. In contrast, three non-pathogenic missense polymorphisms of tuberin (R261W, M286V, R367Q) in the same region as the disease-causing TSC2 mutations did not. These results indicate a requirement for interaction in critical growth suppressing functions of hamartin and tuberin.

LD-PCR coupled to long-read direct sequencing: an approach for mutation detection in genes with compact genomic structures

A number of techniques have been developed as primary screens to scan for DNA sequence variants, including denaturing gradient gel electrophoresis, denaturing high-performance liquid chromatography, single-strand conformation polymorphism and heteroduplex analysis. Variant alleles detected by these assays are subsequently characterised by DNA sequencing. Sequencing itself is rarely used as a primary screen because of labour intensity, cost, and, upon automation, occasional inaccuracy in identifying heterozygous sites. We have previously developed an approach based on coupling long-distance PCR (LD-PCR) to long-read direct sequencing to allow the detection of mutations in the approximately 1.1 kb exon 3 of MECP2. Our use of dye-labelled primers generated high-quality bi-directional sequence runs > 650 bp and allowed easy discrimination of heterozygous bases. We now describe the application of this approach to the detection of mutations in a considerably larger 6.35 kb LD-PCR fragment spanning 10 exons (exons 32-41) of the structurally complex, but genomically compact, TSC2 gene. In a blind analysis, 15/15 previously characterised mutations were successfully identified using seven overlapping bi-directional sequencing reactions. Our approach of long-read sequencing of long-distance PCR products may allow rapid sequencing of multiple exons of compact genes and may be appropriate as a highly sensitive primary screen for mutations.

Long-read sequence analysis of the MECP2 gene in Rett syndrome patients: correlation of disease severity with mutation type and location

Mutations in the methyl-CpG-binding protein gene MECP2 at Xq28 cause Rett syndrome (RTT), an X-linked dominant neurodevelopmental disorder characterized by a period of stagnation followed by regression in the development of young girls. Mutations were sought in MECP2 in 48 females with classical sporadic RTT, seven families with possible familial RTT and five sporadic females with features suggestive, but not diagnostic of RTT. Long distance PCR coupled with long-read direct sequencing was employed to sequence the entire MECP2 gene coding region in all cases. Mutations were identified in 44/55 (80%) unrelated classical sporadic and familial RTT patients, but only 1/5 (20%) sporadic cases with suggestive but non-diagnostic features of RTT. Twenty-one different mutations were identified (12 missense, four nonsense and five frame-shift mutations); 14 of these were novel. All missense mutations were located either in the methyl-CpG-binding domain or in the transcription repression domain. Nine recurrent mutations were characterized in a total of 33 unrelated cases (73% of all cases with MECP2 mutations). Significantly milder disease was noted in patients carrying missense mutations as compared with those with truncating mutations ( P = 0. 0023), and milder disease was associated with late as compared with early truncating mutations ( P = 0.0190).

Heterotopic pancreas as lead point in intussusception: new variant of vitellointestinal tract malformation

Two cases of intussusception are reported with heterotopic pancreatic tissue attached to and draining into the ileum. The first patient, a boy aged 16 months, presented with ileoileal intussusception. The diagnosis was confirmed on ultrasound scan. Laparotomy and resection were performed. A 12-mm nodule of heterotopic pancreatic tissue was identified in the ileal serosa at the apex of the intussusceptum, fully formed with acinar tissue, islets, and draining duct. The second patient, also a boy aged 16 months, presented with obstructed ileocolic intussusception in which the lead point at surgery resembled a Meckel's diverticulum. Histopathology revealed a similar 10-mm nodule of fully formed pancreatic tissue in the ileal serosal tissues, with some acinar tissue extending through the wall of the intestine alongside ductal structures. In both cases there was ectopic gastric mucosa either in the distal part of the draining duct or in the small intestine itself at the opening. Heterotopic pancreas is a rare cause of intussusception. We propose that this lesion is of vitellointestinal tract origin, conceptually similar to a Meckel's diverticulum but without a diverticulum as such. Heterotopic pancreatic tissue occurring alone is more common in the proximal small intestine, duodenum, and stomach than in the ileum, and it is often asymptomatic.

Comprehensive mutation analysis of TSC1 and TSC2-and phenotypic correlations in 150 families with tuberous sclerosis

Tuberous sclerosis (TSC [MIM 191090 and MIM 191100]) is an autosomal dominant disorder characterized by hamartomas in many organs. Two thirds of cases are sporadic and are thought to represent new mutations. TSC is caused by mutations affecting either of the presumed tumor-suppressor genes, TSC1 and TSC2. Both appear to function as tumor suppressors, because somatic loss or intragenic mutation of the corresponding wild-type allele is seen in the associated hamartomas. Here we report the first comprehensive mutation analysis of TSC1 and TSC2 in a cohort of 150 unrelated TSC patients and their families, using heteroduplex and SSCP analysis of all coding exons and using pulsed-field gel electrophoresis and conventional Southern blot analysis and long PCR to screen for large rearrangements. Mutations were characterized in 120 (80%) of the 150 cases, affecting TSC1 in 22 cases and TSC2 in 98 cases. TSC1 mutations were significantly underrepresented in sporadic cases (P=. 000185). Twenty-two patients had TSC2 missense mutations that were found predominantly in the GAP-related domain (eight cases) and in a small region encoded in exons 16 and 17, between nucleotides 1849 and 1859 (eight cases), consistent with the presence of residues performing key functions at these sites. In contrast, all TSC1 mutations were predicted to be truncating, consistent with a structural or adapter role for the encoded protein. Intellectual disability was significantly more frequent in TSC2 sporadic cases than in TSC1 sporadic cases (P=.0145). These data provide the first representative picture of the distribution and spectrum of mutations across the TSC1 and TSC2 loci in clinically ascertained TSC and support a difference in severity of TSC1- and TSC2-associated disease.

Gross deletions of the neurofibromatosis type 1 (NF1) gene are predominantly of maternal origin and commonly associated with a learning disability, dysmorphic features and developmental delay

Mutation screening in neurofibromatosis type 1 (NF1) families has long been hampered by the complexity of the NF1 gene. By using a novel multi-track screening strategy, 67 NF1 families (54 two-generation, 13 three-generation) with a de novo mutation in the germline of the first generation were studied with two extragenic and 11 intragenic markers. The pathological lesion was identified in 31 cases. Loss of heterozygosity (LOH) in the affected individual revealed a gross gene deletion in 15 of the two-generation families; in 12 (80%) of them, the deletion was maternally derived. Eleven patients with a gross deletion exhibited developmental delay, ten had dysmorphic features and six manifested a learning disability. No gross deletion was apparent in any of the 13 three-generation families, suggesting that such lesions are subject to more intense selection. In these families, the new mutation was of paternal origin in 11 kindreds and the underlying mutational event could be characterised in three of them.

Improved molecular diagnosis of facioscapulohumeral muscular dystrophy (FSHD): validation of the differential double digestion for FSHD

A major advance in the molecular diagnosis of facioscapulohumeral muscular dystrophy is the recently reported elimination of confounding DNA fragments arising from homologous sequences located at 10q26. In order to evaluate the specificity and sensitivity of this important diagnostic test, we have compared a group of 130 patients fulfilling the diagnostic criteria for FSHD with 200 control subjects not known to have an increased risk of having an FSHD mutation. Among the FSHD cases the smallest BlnI/EcoRI fragment sizes ranged from 10 to > 48 kb with 94.6% (95% CI 89.2-97.8%) of cases having fragment sizes of 34 kb or less. Among the 400 chromosomes from controls the smallest BlnI/EcoRI fragment observed with the EcoRI/BlnI double restriction enzyme digest was 38 kb +/- 2 kb, suggesting a test specificity at a fragment size < 34 kb of or very near to 100% (lower 95% CI 98.2%). Test sensitivity at < 34 kb is estimated at 94.6% (95% CI 89.2-97.8%), all outliers having fragments > 38 kb. The Southern blot analysis with DNA probe p13E-11 has created a valuable molecular diagnostic test for FSHD.

Characterization and significance of nine novel mutations in exon 16 of the neurofibromatosis type 1 (NF1) gene

Nine novel mutations have been characterized as the result of screening exon 16 of the human NF1 gene in 465 unrelated neurofibromatosis type 1 patients. These lesions include three nonsense and two missense mutations, two deletions, one duplication, and one mutation in the 5' splice site of intron 16. Although exon 16 is the largest NF1 exon, no mutations have so far been reported in this region. This apparent paucity of lesions may be due either to a reduced functional importance of exon 16 or a screening bias or both. However, consideration of the mutability of exon 16 in comparison with other exons suggests that, at least for single base pair substitutions, no such factors need be invoked. Any previous lack of exon 16 mutations in this category would be explicable in terms of a lower propensity to mutate for codons in this gene region.

Integration of hepatitis B vaccination into the expanded programme on immunization in Chonburi and Chiangmai provinces, Thailand

Hepatitis B (HB) immunization was introduced as part of the expanded programme on immunization (EPI) in two provinces in Thailand and evaluated over a four year period. Three doses of HB vaccine were offered to 60,980 newborns at birth, 2 and 6 months of age. The overall coverage for complete HB immunization was 90.4%. Serosurveys of randomly selected children under the age of 5 years were undertaken before and at the end of the project. Levels of HBsAg positivity were reduced by 85%, and there was a corresponding 70% increase in protective immunity. These findings demonstrate that HB immunization can be successfully integrated into EPI without adverse effect on coverage rates of other antigens, and results in a marked reduction in the rate of chronic carriage of HB virus in preschool age children.

Mutational and functional analysis of the neurofibromatosis type 1 (NF1) gene

Neurofibromatosis type 1 (NF1) is one of the most common autosomal dominant disorders. It is caused by mutations in the NF1 gene which comprises 60 exons and is located on chromosome 17q. The NF1 gene product, neurofibromin, displays partial homology to GTPase-activating protein (GAP). The GAP-related domain (GRD), encoded by exons 20-27a, is the only region of neurofibromin to which a biological function has been ascribed. A total of 320 unrelated NF1 patients were screened for mutations in the GRD-encoding region of the NF1 gene. Sixteen different lesions in the NF1 GRD region were identified in a total of 20 patients. Of these lesions, 14 are novel and together comprise three missense, two nonsense and three splice site mutations plus six deletions of between 1 and 4 bp. The effect of one of the missense mutations (R1391S) was studied by in vitro expression of a site-directed mutant and GAP activity assay. The mutant protein, R1391S, was found to be some 300-fold less active than wild-type NF1 GRD. The mutations reported in this study therefore provide further material for the functional analysis of neurofibromin as well as an insight into the mutational spectrum of the NF1 GRD.

Characterization of six mutations in exon 37 of neurofibromatosis type 1 gene

Neurofibromatosis type 1 (NF1) is one of the most common inherited disorders, with an incidence of 1 in 3,000. We screened a total of 320 unrelated NF1 patients for mutations in exon 37 of the NF1 gene. Six independent mutations were identified, of which three are novel, and these include a recurrent nonsense mutation identified in 2 unrelated patients at codon 2281 (G2281X), a 1-bp insertion (6791 ins A) resulting in a change of TAG (tyrosine) to a TAA (stop codon), and a 3-bp deletion (6839 del TAC) which generated a frameshift. Another recurrent nonsense mutation, Y2264X, which was detected in 2 unrelated patients in this study, was also previously reported in 2 NF1 individuals. All the mutations were identified within a contiguous 49-bp sequence. Further studies are warranted to support the notion that this region of the gene contains highly mutable sequences.

A cytogenetic deletion, del(17)(q11.22q21.1), in a patient with sporadic neurofibromatosis type 1 (NF1) associated with dysmorphism and developmental delay

We report the first visible cytogenetic deletion involving the NF1 gene in a patient with sporadic neurofibromatosis, dysmorphic features, and marked developmental delay. The combined evidence of molecular and cytogenetic techniques based on dosage reduction, hemizygosity for microsatellite markers, high resolution G banding, and FISH analysis, predicts this deletion to be approximately 7 Mb in size. Our findings highlight the importance of conducting a detailed cytogenetic and FISH analysis in patients with NF1 who have additional dysmorphic features or particularly severe learning difficulties.

Characterisation of germline mutations in the neurofibromatosis type 1 (NF1) gene

Neurofibromatosis type 1 is one of the most common inherited disorders with an incidence of 1 in 3000. The search for NF1 mutations has been hampered by the overall size of the gene, the large number of exons, and the high mutation rate. To date, fewer than 90 mutations have been reported to the NF1 mutation analysis consortium and the details on 76 mutations have been published. We have identified five new mutations using single strand conformation polymorphism (SSCP) and heteroduplex analysis (HA) and three intragenic deletions with the microsatellite markers. Of the five new mutations, two were in exon 27a, two in exon 45, and one in exon 49 and these include 4630delA, 4572delC, R7846X, T7828A, and one in the 3' untranslated region (3' UTR). The two nucleotide alterations in exon 27a and the one in exon 45 are predicted to produce a truncated protein.

Towards the finer mapping of facioscapulohumeral muscular dystrophy at 4q35: construction of a laser microdissection library

Facioscapulohumeral muscular dystrophy (FSHD) is an autosomal-dominant disorder which has been mapped to the 4q35 region. In order to saturate this distal 4q region with DNA markers, a laser-based chromosomal microdissection and microcloning procedure was used to construct a genomic library from the distal 20% of chromosome 4, derived from a single human metaphase spread. Of the 100 microclones analyzed from this library, 94 clones contained inserts sized from 80-800 bp, with an average size of 340 bp. Less than 20% of these clones hybridized to human repeat sequences. Seventy-two single-copy clones were further characterized by Southern blot hybridization against a DNA panel of somatic cell hybrids, containing various regions of chromosome 4. Forty-two clones mapped to chromosome 4, of which 8 clones mapped into the relevant 4q35 region. Twenty of these chromosome 4-specific clones were screened against "zoo-blots"; 11 clones, of which 3 mapped to 4q35, identified conserved sequences. This is the first report to describe the isolation of potential expressed sequences derived from the FSHD region. These chromosome region-specific microclones will be useful in the construction of the physical map of the region, the positional cloning of potential disease-associated genes, and the identification of additional polymorphic markers from within the distal 4q region.

Correlation between fragment size at D4F104S1 and age at onset or at wheelchair use, with a possible generational effect, accounts for much phenotypic variation in 4q35-facioscapulohumeral muscular dystrophy (FSHD)

In facioscapulohumeral muscular dystrophy (FSHD), the wide range of clinical severity observed both within and between families has obscured past attempts to identify any phenotypic differences between families from which phenotype-genotype correlation could proposed, although it is noted that age at onset is youngest and severity greatest in isolated cases. From 14/16 large 4q35-linked FSHD families, and 25/34 isolated cases exhibiting a de novo D4F104S1 DNA fragment, we find a significant correlation between proband age at onset and FSHD-associated D4F104S1 fragment size (r = 0.56; p < 0.001), with the smallest fragments occurring in isolated cases. A similar correlation (r = 0.70; p < 0.01) with fragment size is observed for age to loss of ambulation in 16 subjects using a wheelchair. We find also that age at onset appears younger with successive generations in the 4q35 families. We propose that fragment size at D4F104S1, together with a possible generational effect, accounts for a significant part of the wide phenotypic variation in FSHD. Our results predict a more limited range for severity within families, and in one family with a 4q35-linked 38kb fragment support scapulohumeral presentation without facial involvement as a late onset variant of FSHD. We propose that in FSHD, quantitative variation in a uniform mutation mechanism influences age at onset, but by deletion rather than expansion of DNA.

Germinal mosaicism in facioscapulohumeral muscular dystrophy (FSHD)

Facioscapulohumeral dystrophy (FSHD) is an autosomal-dominant neuromuscular disorder with a prevalence of 1 in 20,000. The DNA marker p13E-11 (D4F104S1) detects a de novo DNA rearrangement in the majority of sporadic and FSHD cases. These rearrangements consist of deletions of multiple copies of tandem repeat (D4Z4). We have studied 34 new mutation FSHD families of which 26 showed a de novo fragment with p13E-11. In three of the remaining eight families without a de novo fragment, germinal mosaicism was noted. In each case, the proband had inherited a small EcoR1 fragment from the clinically unaffected mother; however, the hybridization signal intensity of this fragment in the mother's DNA was significantly reduced in all three families. This is the first study to describe such mosaicism in FSHD families using DNA analysis and therefore has a considerable significance for genetic counseling and prenatal diagnosis.

Germinal mosaicism in facioscapulohumeral muscular dystrophy (FSHD)

Facioscapulohumeral dystrophy (FSHD) is an autosomal-dominant neuromuscular disorder with a prevalence of 1 in 20,000. The DNA marker p13E-11 (D4F104S1) detects a de novo DNA rearrangement in the majority of sporadic and FSHD cases. These rearrangements consist of deletions of multiple copies of tandem repeat (D4Z4). We have studied 34 new mutation FSHD families of which 26 showed a de novo fragment with p13E-11. In three of the remaining eight families without a de novo fragment, germinal mosaicism was noted. In each case, the proband had inherited a small EcoR1 fragment from the clinically unaffected mother; however, the hybridization signal intensity of this fragment in the mother's DNA was significantly reduced in all three families. This is the first study to describe such mosaicism in FSHD families using DNA analysis and therefore has a considerable significance for genetic counseling and prenatal diagnosis.

Phenotypic-genotypic correlation will assist genetic counseling in 4q35-facioscapulohumeral muscular dystrophy

The wide range of severity in facioscapulohumeral muscular dystrophy (FSHD) complicates genetic advice, although onset age is youngest and severity is greatest in isolated cases. From 14 of 16 large FSHD families which are 4q35 linked, and from 25 of 34 isolated cases exhibiting a de novo D4F104S1 DNA fragment, we find a correlation between proband age at onset and FSHD-associated D4F104S1 fragment size (r = 0.56; P < 0.001), with the smallest fragments occurring in isolated cases. A 4q35-linked 38-kb fragment in one family supports scapulohumeral presentation without facial involvement as a milder late-onset variant of FSHD, and with apparent "unaffected" recombinants in small families, suggests that nonpenetrance is more likely with large fragment sizes. Our results, predicting a more limited range for severity within families, and suggesting > 85% of FSHD maps to 4q35, will facilitate genetic counseling. We propose that quantitative variation in a uniform mutation mechanism influences age at onset, but by deletion rather than expansion of DNA.

A scapular onset muscular dystrophy without facial involvement: possible allelism with facioscapulohumeral muscular dystrophy

A dominantly inherited muscular dystrophy with onset in the shoulder girdle and later progression to the lower limbs is described. The disorder was clinically distinguishable from known facioscapulohumeral, scapulohumeral and limb girdle syndromes. A 38 kb allele detected by probe p13E-11 (D4F104S1) segregated with the disease. Linkage analysis gave a maximum lod score of z = 1.61 at theta = 0.01 with the 4q35 markers D4S184 (affected only analysis z = 1.20 at theta = 0.01) suggesting probable allelism with facioscapulohumeral muscular dystrophy.