Further delineation of the rare GDACCF (global developmental delay, absent or hypoplastic corpus callosum, dysmorphic facies syndrome): genotype and phenotype of 22 patients with ZNF148 mutations

BACKGROUND

Pathogenic variants in the zinc finger protein coding genes are rare causes of intellectual disability and congenital malformations. Mutations in the ZNF148 gene causing GDACCF syndrome (global developmental delay, absent or hypoplastic corpus callosum, dysmorphic facies; MIM #617260) have been reported in five individuals so far.

METHODS

As a result of an international collaboration using GeneMatcher Phenome Central Repository and personal communications, here we describe the clinical and molecular genetic characteristics of 22 previously unreported individuals.

RESULTS

The core clinical phenotype is characterised by developmental delay particularly in the domain of speech development, postnatal growth retardation, microcephaly and facial dysmorphism. Corpus callosum abnormalities appear less frequently than suggested by previous observations. The identified mutations concerned nonsense or frameshift variants that were mainly located in the last exon of the ZNF148 gene. Heterozygous deletion including the entire ZNF148 gene was found in only one case. Most mutations occurred de novo, but were inherited from an affected parent in two families.

CONCLUSION

The GDACCF syndrome is clinically diverse, and a genotype-first approach, that is, exome sequencing is recommended for establishing a genetic diagnosis rather than a phenotype-first approach. However, the syndrome may be suspected based on some recurrent, recognisable features. Corpus callosum anomalies were not as constant as previously suggested, we therefore recommend to replace the term 'GDACCF syndrome' with 'ZNF148-related neurodevelopmental disorder'.

Variants in the WDR44 WD40-repeat domain cause a spectrum of ciliopathy by impairing ciliogenesis initiation

WDR44 prevents ciliogenesis initiation by regulating RAB11-dependent vesicle trafficking. Here, we describe male patients with missense and nonsense variants within the WD40 repeats (WDR) of WDR44, an X-linked gene product, who display ciliopathy-related developmental phenotypes that we can model in zebrafish. The patient phenotypic spectrum includes developmental delay/intellectual disability, hypotonia, distinct craniofacial features and variable presence of brain, renal, cardiac and musculoskeletal abnormalities. We demonstrate that WDR44 variants associated with more severe disease impair ciliogenesis initiation and ciliary signaling. Because WDR44 negatively regulates ciliogenesis, it was surprising that pathogenic missense variants showed reduced abundance, which we link to misfolding of WDR autonomous repeats and degradation by the proteasome. We discover that disease severity correlates with increased RAB11 binding, which we propose drives ciliogenesis initiation dysregulation. Finally, we discover interdomain interactions between the WDR and NH2-terminal region that contains the RAB11 binding domain (RBD) and show patient variants disrupt this association. This study provides new insights into WDR44 WDR structure and characterizes a new syndrome that could result from impaired ciliogenesis.

Spliceosome malfunction causes neurodevelopmental disorders with overlapping features

Pre-mRNA splicing is a highly coordinated process. While its dysregulation has been linked to neurological deficits, our understanding of the underlying molecular and cellular mechanisms remains limited. We implicated pathogenic variants in U2AF2 and PRPF19, encoding spliceosome subunits in neurodevelopmental disorders (NDDs), by identifying 46 unrelated individuals with 23 de novo U2AF2 missense variants (including 7 recurrent variants in 30 individuals) and 6 individuals with de novo PRPF19 variants. Eight U2AF2 variants dysregulated splicing of a model substrate. Neuritogenesis was reduced in human neurons differentiated from human pluripotent stem cells carrying two U2AF2 hyper-recurrent variants. Neural loss of function (LoF) of the Drosophila orthologs U2af50 and Prp19 led to lethality, abnormal mushroom body (MB) patterning, and social deficits, which were differentially rescued by wild-type and mutant U2AF2 or PRPF19. Transcriptome profiling revealed splicing substrates or effectors (including Rbfox1, a third splicing factor), which rescued MB defects in U2af50-deficient flies. Upon reanalysis of negative clinical exomes followed by data sharing, we further identified 6 patients with NDD who carried RBFOX1 missense variants which, by in vitro testing, showed LoF. Our study implicates 3 splicing factors as NDD-causative genes and establishes a genetic network with hierarchy underlying human brain development and function.

Chimeric Antigen Receptor T Cell Therapy Targeting Epithelial Cell Adhesion Molecule in Gastric Cancer: Mechanisms of Tumor Resistance

Epithelial cell adhesion molecule (EpCAM) is a tumor-associated antigen that is frequently overexpressed in various carcinomas. We have developed chimeric antigen receptor (CAR) T cells specifically targeting EpCAM for the treatment of gastric cancer. This study sought to unravel the precise mechanisms by which tumors evade immune surveillance and develop resistance to CAR T cell therapy. Through a combination of whole-body CAR T cell imaging and single-cell multiomic analyses, we uncovered intricate interactions between tumors and tumor-infiltrating lymphocytes (TILs). In a gastric cancer model, tumor-infiltrating CD8 T cells exhibited both cytotoxic and exhausted phenotypes, while CD4 T cells were mainly regulatory T cells. A T cell receptor (TCR) clonal analysis provided evidence of CAR T cell proliferation and clonal expansion within resistant tumors, which was substantiated by whole-body CAR T cell imaging. Furthermore, single-cell transcriptomics showed that tumor cells in mice with refractory or relapsing outcomes were enriched for genes involved in major histocompatibility complex (MHC) and antigen presentation pathways, interferon-γ and interferon-α responses, mitochondrial activities, and a set of genes (e.g., CD74, IDO1, IFI27) linked to tumor progression and unfavorable disease prognoses. This research highlights an approach that combines imaging and multiomic methodologies to concurrently characterize the evolution of tumors and the differentiation of CAR T cells.

Mechanisms of mRNA processing defects in inherited THOC6 intellectual disability syndrome

THOC6 is the genetic basis of autosomal recessive THOC6 Intellectual Disability Syndrome (TIDS). THOC6 facilitates the formation of the Transcription Export complex (TREX) tetramer, composed of four THO monomers. The TREX tetramer supports mammalian mRNA processing that is distinct from yeast TREX dimer functions. Human and mouse TIDS model systems allow novel THOC6-dependent TREX tetramer functions to be investigated. Biallelic loss-of-functon(LOF) THOC6 variants do not influence the expression and localization of TREX members in human cells, but our data suggests reduced binding affinity of ALYREF. Impairment of TREX nuclear export functions were not detected in cells with biallelic THOC6 LOF. Instead, mRNA mis-splicing was observed in human and mouse neural tissue, revealing novel insights into THOC6-mediated TREX coordination of mRNA processing. We demonstrate that THOC6 is required for regulation of key signaling pathways in human corticogenesis that dictate the transition from proliferative to neurogenic divisions that may inform TIDS neuropathology.

Mosaicism of common pathogenic MECP2 variants identified in two males with a clinical diagnosis of Rett syndrome

Rett (RTT) syndrome, a neurodevelopmental disorder caused by pathogenic variation in the MECP2 gene, is characterized by developmental regression, loss of purposeful hand movements, stereotypic hand movements, abnormal gait, and loss of spoken language. Due to the X-linked inheritance pattern, RTT is typically limited to females. Recent studies revealed somatic mosaicism in MECP2 in male patients with RTT-like phenotypes. While detecting mosaic variation using Sanger sequencing is theoretically possible for mosaicism over ~15%-20%, several variables, including efficiency of PCR, background noise, and/or human error, contribute to a low detection rate using this technology. Mosaic variants in two males were detected by next generation sequencing (NGS; Case 1) and by Sanger re-sequencing (Case 2). Both had targeted digital PCR (dPCR) to confirm the variants. In this report, we present two males with classic RTT syndrome in whom we identified pathogenic variation in the MECP2 gene in the mosaic state (c.730C > T (p.Gln244*) in Patient 1 and c.397C > T (p.Arg133Cys) in Patient 2). In addition, estimates and measures of mosaic variant fraction were surprisingly similar between Sanger sequencing, NGS, and dPCR. The mosaic state of these variants contributed to a lengthy diagnostic odyssey for these patients. While NGS and even Sanger sequencing may be viable methods of detecting mosaic variation in DNA or RNA samples, applying targeted dPCR to supplement these sequencing technologies would provide confirmation of somatic mosaicism and mosaic fraction.

FC044: Heterozygous Variants in Kinase Domain of NEK8 cause an Autosomal-Dominant Ciliopathy

BACKGROUND AND AIMS

NEK8/NPHP9 encodes a protein that localizes to the primary cilium. Biallelic NEK8 variants are known to cause multiorgan developmental defects, including kidney cystic dysplasia and extensive extra-renal defects, with heterozygous carrier parents being asymptomatic [1]. This autosomal recessive inheritance is the most common inheritance mode for ciliopathies. Complementary to this, we now propose a dominant negative effect for specific heterozygous NEK8 missense variants in the kinase domain resulting in an autosomal-dominant ciliopathy.

METHOD

We performed genetic testing in patients from several medical centers. To explore the consequences of the identified NEK8 variants, we are performing cilia staining assays in patients' skin fibroblast and kidney cells, as well as in mIMCD3 cells overexpressing the identified variants. Furthermore, we are examining the impact of the NEK8 variants on replication stress response.

RESULTS

We identified three distinct heterozygous NEK8 variants in 12 families (Table 1), all leading to missense alterations in the kinase domain. Interestingly the p.Arg45Trp variant is a recurrent variant we detected in 10 unrelated families. All patients have a kidney phenotype that varies from mild focal segmental glomerulosclerosis to prenatal presentation with polycystic kidneys. Most patients have kidney failure needing kidney replacement therapy at varying ages of onset. In all patients, we thoroughly checked whether a second variant could be found. Furthermore, the large symptomatic family and de novo occurrences favor a dominant inheritance mode. Our preliminary results from functional studies show abnormal primary cilia formation in serum-starved cells as well as increased replication stress.

CONCLUSION

We present the first evidence for a pathogenic effect of heterozygous NEK8 variants. Remarkably our patients present with a kidney limited phenotype as compared to the multiorgan defects found in patients with biallelic variants. This reveals a new mode of inheritance for NEK8 variants and expands genotype-phenotype correlations for this gene.

Characterization of glycosylphosphatidylinositol biosynthesis defects by clinical features, flow cytometry, and automated image analysis

Background

Glycosylphosphatidylinositol biosynthesis defects (GPIBDs) cause a group of phenotypically overlapping recessive syndromes with intellectual disability, for which pathogenic mutations have been described in 16 genes of the corresponding molecular pathway. An elevated serum activity of alkaline phosphatase (AP), a GPI-linked enzyme, has been used to assign GPIBDs to the phenotypic series of hyperphosphatasia with mental retardation syndrome (HPMRS) and to distinguish them from another subset of GPIBDs, termed multiple congenital anomalies hypotonia seizures syndrome (MCAHS). However, the increasing number of individuals with a GPIBD shows that hyperphosphatasia is a variable feature that is not ideal for a clinical classification.

Methods

We studied the discriminatory power of multiple GPI-linked substrates that were assessed by flow cytometry in blood cells and fibroblasts of 39 and 14 individuals with a GPIBD, respectively. On the phenotypic level, we evaluated the frequency of occurrence of clinical symptoms and analyzed the performance of computer-assisted image analysis of the facial gestalt in 91 individuals.

Results

We found that certain malformations such as Morbus Hirschsprung and diaphragmatic defects are more likely to be associated with particular gene defects (PIGV, PGAP3, PIGN). However, especially at the severe end of the clinical spectrum of HPMRS, there is a high phenotypic overlap with MCAHS. Elevation of AP has also been documented in some of the individuals with MCAHS, namely those with PIGA mutations. Although the impairment of GPI-linked substrates is supposed to play the key role in the pathophysiology of GPIBDs, we could not observe gene-specific profiles for flow cytometric markers or a correlation between their cell surface levels and the severity of the phenotype. In contrast, it was facial recognition software that achieved the highest accuracy in predicting the disease-causing gene in a GPIBD.

Conclusions

Due to the overlapping clinical spectrum of both HPMRS and MCAHS in the majority of affected individuals, the elevation of AP and the reduced surface levels of GPI-linked markers in both groups, a common classification as GPIBDs is recommended. The effectiveness of computer-assisted gestalt analysis for the correct gene inference in a GPIBD and probably beyond is remarkable and illustrates how the information contained in human faces is pivotal in the delineation of genetic entities.

Electronic supplementary material

The online version of this article (doi:10.1186/s13073-017-0510-5) contains supplementary material, which is available to authorized users.

The Mdm1 Locus and Maize Resistance to Maize dwarf mosaic virus

Previously, Mdm1, a gene controlling resistance to Maize dwarf mosaic virus (MDMV), was identified in the inbred line Pa405. The gene was tightly linked to the restriction fragment length polymorphism marker umc85 on the short arm of chromosome 6. This chromosomal region is also the location of resistance genes to two other viruses in the family Potyviridae, Sugarcane mosaic virus (SCMV) and Wheat streak mosaic virus (WSMV). A diverse collection of 115 maize inbred lines was evaluated for resistance to MDMV and SCMV, and for MDMV resistance loci on chromosome 6S. Forty-six resistant inbred lines were crossed to three MDMVsusceptible inbred lines to develop F2 populations. The F2 populations were inoculated with MDMV and scored for infection and symptom type. Environmental factors influenced both the rate and type of symptom development. Bulked segregant analysis of each F2 population indicated that, in 42 of 43 MDMV-resistant lines, chromosome 6S markers found in the resistant parent also were present in the bulked resistant but not the susceptible tissue. Markers previously associated with resistance to both SCMV and WSMV on chromosome 3 and to WSMV on chromosome 10 were associated with resistance in nine and seven of the F2 populations, respectively. These data suggest that Mdm1 or closely linked genes on chromosome 6S are associated with MDMV resistance in most germplasm, but that other loci also may affect resistance.

Isolation, transmission and purification of the High Plains virus

The wheat curl mite (Aceria tosichella Keifer) often simultaneously transmits the High Plains virus and Wheat streak mosaic virus under field conditions, resulting in doubly infected plants. In this study, a pure culture of the High Plains virus (isolate HPV95ID), which was infected with both High Plains virus and Wheat streak mosaic virus, was mechanically transmitted from barley (Hordeum vulgáre L.) to maize (Zea mays L.) by vascular puncture inoculation. Different water temperatures and durations for soaking kernels at pre-inoculation and different incubation temperatures and durations at post-inoculation on transmission of High Plains virus were studied. Transmissions of the High Plains virus were significantly different for post-inoculation incubations at 11, 21, or 30 degrees C after a 2 h pre-inoculation soaking at 30 degrees C and post-inoculation incubations of kernels for 1 day versus 2 days. Use of Cs2SO4 in a partial purification protocol resulted in infectious final fractions. Bioassays, serological assays, analyses by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and examinations by electron microscopy confirmed isolation of a pure culture of High Plains virus from infectious final partially purified fractions. We demonstrate infectivity of the final fractions and associate it with the High Plains disease symptoms, the 32 kDa protein and double membrane bodies and discuss this evidence to support the viral nature of High Plains virus.

Identification of quantitative trait loci controlling resistance to maize chlorotic dwarf virus

Ineffective screening methods and low levels of disease resistance have hampered genetic analysis of maize (Zea mays L.) resistance to disease caused by maize chlorotic dwarf virus (MCDV). Progeny from a cross between the highly resistant maize inbred line Oh1VI and the susceptible inbred line Va35 were evaluated for MCDV symptoms after multiple virus inoculations, using the viral vector Graminella nigrifrons. Symptom severity scores from three rating dates were used to calculate area under the disease progress curve (AUDPC) scores for vein banding, leaf twist and tear, and whorl chlorosis. AUDPC scores for the F(2) population indicated that MCDV resistance was quantitatively inherited. Genotypic and phenotypic analyses of 314 F(2) individuals were compared using composite interval mapping (CIM) and analysis of variance. CIM identified two major quantitative trait loci (QTL) on chromosomes 3 and 10 and two minor QTL on chromosomes 4 and 6. Resistance was additive, with alleles from Oh1VI at the loci on chromosomes 3 and 10 contributing equally to resistance.

Biological and Molecular Variability Among High Plains virus Isolates

The High Plains virus (HPV), vectored by the wheat curl mite (WCM) (Aceria tosichella), causes a severe disease of maize (Zea mays) in the U. S. High Plains. In the present study, five HPV isolates from five states were separated from co-infecting Wheat streak mosaic virus and their molecular and biological variability studied. Molecular studies involved time-of-flight mass spectrometry (TOFMS) to determine amino acid sequence variability of the 32-kDa nucleoprotein (32 np) of the isolates. Biological studies involved testing the ability of the five HPV isolates to infect a maize line previously shown to have resistance. Inoculations of the HPV isolates were conducted using vascular puncture inoculation (VPI) and viruliferous WCM. TOFMS analyses demonstrated an 18-amino acid sequence in the isolates at the N-terminus of the 32 np, the presence of amino acid sequence differences among the isolates, and variability among amino acid sequences of the 32 np of some isolates. Three of the five HPV isolates infected the resistant maize inbred, B73, using VPI, and two of the same three HPV isolates infected this line using WCM inoculation, albeit low numbers of plants were infected by each technique.

The use of continuous infusion topotecan in persistent and recurrent ovarian cancer

We retrospectively review our experience with continuous infusion topotecan for the treatment of persistent or recurrent ovarian cancer in this paper. Nine patients were identified who were treated at the University of California Los Angeles Medical Center between January 1997 and December 1999 using a 14-21 day continuous infusion schedule (0.3-0.7 mg/m2/d). Dose adjustments were performed for grade 3-4 toxicities and treatment was discontinued for persistent severe toxicity or progressive disease. Response to treatment was analyzed and stratified by platinum refractory, resistant, and sensitive disease. A total of 41 treatment cycles were given to nine patients with a median of five per patient (range 1-11). Median follow-up was 8 months. There were two partial responses (22%) and four patients had stable disease (44%), which included two patients with platinum-refractory tumors. No grade 3 or 4 hematologic toxicities were observed. However, two patients suffered grade 3 gastrointestinal toxicity during the first cycle leading to discontinuation of topotecan administration. There was no cumulative toxicity. Topotecan administered by continuous infusion demonstrated response rates comparable to other dosing schedules with minimal hematologic toxicity. Treatment of patients with persistent or recurrent ovarian cancer with continuous infusion topotecan warrants further investigation.

The use of continuous infusion topotecan in persistent and recurrent ovarian cancer

We retrospectively review our experience with continuous infusion topotecan for the treatment of persistent or recurrent ovarian cancer in this paper. Nine patients were identified who were treated at the University of California Los Angeles Medical Center between January 1997 and December 1999 using a 14–21 day continuous infusion schedule (0.3–0.7 mg/m2/d). Dose adjustments were performed for grade 3–4 toxicities and treatment was discontinued for persistent severe toxicity or progressive disease. Response to treatment was analyzed and stratified by platinum refractory, resistant, and sensitive disease. A total of 41 treatment cycles were given to nine patients with a median of five per patient (range 1–11). Median follow-up was 8 months. There were two partial responses (22%) and four patients had stable disease (44%), which included two patients with platinum-refractory tumors. No grade 3 or 4 hematologic toxicities were observed. However, two patients suffered grade 3 gastrointestinal toxicity during the first cycle leading to discontinuation of topotecan administration. There was no cumulative toxicity. Topotecan administered by continuous infusion demonstrated response rates comparable to other dosing schedules with minimal hematologic toxicity. Treatment of patients with persistent or recurrent ovarian cancer with continuous infusion topotecan warrants further investigation.

Differential Transmission of Isolates of the High Plains virus by Different Sources of Wheat Curl Mites

High Plains virus (HPV) isolates from Colorado, Idaho, Kansas, Texas, and Utah were serologically related, had similar relative molecular masses (sodium dodecyl sulfate-polyacrylamide gel electrophoresis) for the 32-kDa diagnostic HPV protein, and were transmissible and maintained free of Wheat streak mosaic virus (WSMV) by vascular puncture inoculation. Collections of wheat curl mites (Aceria tosichella Keifer; WCM) from Kansas, Montana, Nebraska, South Dakota, and Texas differentially transmitted these isolates. For collections from South Dakota and Texas, little or no HPV transmission occurred, whereas WCM from Nebraska and Montana transmitted all five isolates. The collection from Kansas mostly transmitted only one HPV isolate. Aviruliferous or viruliferous WSMV Nebraska WCM transmitted HPV at similar rates and aviruliferous Montana WCM transmitted HPV at lower levels than viruliferous Montana WCM.

Transmission of viral RNA and DNA to maize kernels by vascular puncture inoculation

Vascular puncture inoculation (VPI) is an effective technique for transmission of maize viruses without using arthropods or other biological vectors. It involves using a jeweler's engraving tool to push minuten pins through a droplet of virus inoculum toward the major vascular bundle in the scutellum of germinating kernels. Here, VPI is shown to be useful for introducing RNA and DNA viral genomes into maize. Maize dwarf mosaic potyvirus (MDMV) virions, MDMV genomic RNA, foxtail mosaic potexvirus (FoMV) genomic RNA and maize streak geminivirus (MSV) DNA were introduced into kernels by VPI, and infection rates determined. At high concentrations, both MDMV virion and genomic RNA preparations produced 100% infection of susceptible maize. However, MDMV genomic RNA was transmitted with about 100-fold lower efficiency than virions. FoMV genomic RNA and MSV DNA were transmitted at lower efficiency than the MDMV RNA, and the highest transmission rates were about 50%. Ribonuclease A pretreatment prevented genomic MDMV and FoMV RNA transmission, but not MDMV virion transmission indicating the viral RNA was the infectious entity. Proteinase K (ProK) pretreatment reduced transmission of MDMV RNA suggesting that integrity of the viral genomic protein bound covalently to the viral RNA may be important for efficient transmission.

Maize necrotic streak virus, a New Maize Virus with Similarity to Species of the Family Tombusviridae

A new virus was isolated from maize (Zea mays L.) leaves showing mild mosaic symptoms and coinfected with Maize dwarf mosaic virus. The virus was readily transmitted by vascular puncture inoculation (VPI) but not leaf-rub inoculation. Virus symptoms on susceptible maize included pale green, yellow, or cream-colored spots and streaks measuring 1 to 2 mm on emerging leaves 5 to 7 days post-VPI. As leaves developed, the spots and streaks became spindle-shaped, then coalesced into long, chlorotic bands. These bands became translucent and necrotic around the edges. There was a distinctive chlorosis on the stalks that became necrotic. Based on these distinctive symptoms, the new virus was named Maize necrotic streak virus (MNeSV). The virus was not transmitted by Aphis maidis-radicus, Myzus persicae, Macrosiphum euphorbiae, Rhopalosiphum padi, Dalbulus maidis, Graminella nigrifrons, Perigrinus maidis, or Diabrotica virgifera virgifera under persistent or nonpersistent conditions. Both susceptible and resistant maize genotypes were identified following VPI with MNeSV. The isolated virus had isometric (32 nm) virions and a single 29.5-kDa coat protein. MNeSV was serologically distinct from morphologically similar maize viruses. The 4.3-kb single-stranded RNA genome had 25 to 53% sequence identity with species in the family Tombusviridae.

Quality of care for patients with rheumatoid arthritis

CONTEXT

Patients with rheumatoid arthritis are at risk for substantial morbidity because of their arthritis and premature mortality due to comorbid diseases. However, little is known about the quality of the health care that these patients receive.

OBJECTIVE

To assess the quality of the health care that rheumatoid arthritis patients receive for their arthritis, comorbid diseases, and health care maintenance and to determine the effect of patterns of specialty care on quality.

DESIGN, SETTING, AND PARTICIPANTS

Historical cohort study of 1355 adult rheumatoid arthritis patients enrolled in the fee-for-service or discounted fee-for-service plans of a nationwide US insurance company. Patients were identified and followed up through administrative data between 1991 and 1995.

MAIN OUTCOME MEASURES

Quality scores for arthritis, comorbid disease, and health care maintenance were developed from performance on explicit process measures that related to each of these domains and described the percentage of indicated health care processes performed within each domain during each person-year of the study.

RESULTS

During 4598 person-years of follow-up, quality scores were 62% (95% confidence interval [CI], 61%-64%) for arthritis care, 52% (95% CI, 49%-55%) for comorbid disease care, and 42% (95% CI, 40%-43%) for health care maintenance. Across domains, care patterns including relevant specialists yielded performance scores 30% to 187% higher than those that did not (P<.001) and 45% to 67% of person-years were associated with patterns of care that did not include a relevant specialist. Presence of primary care without specialty care yielded health care maintenance scores that were 43% higher than those for patterns that included neither primary nor relevant specialty care (P<.001).

CONCLUSIONS

In this population, health care quality appears to be suboptimal for arthritis, comorbid disease, and health care maintenance. Patterns of care that included relevant specialists were associated with substantially higher quality across all domains. Patterns that included generalists were associated with substantially higher quality health care maintenance than patterns that included neither a generalist nor a relevant specialist. The optimal roles of primary care physicians and specialists in the care of patients with complex conditions should be reassessed. JAMA. 2000;284:984-992

Tumor necrosis factor-alpha inhibits leptin production in subcutaneous and omental adipocytes from morbidly obese humans

This study was undertaken to examine the regulation of leptin production from human adipocytes by tumor necrosis factor-alpha (TNFalpha). Adipocytes were isolated from adipose tissue obtained during bariatric surgical procedures (17 women and 3 men; body mass index, 52.5 +/- 2.4 kg/m2; age, 40 +/- 3 yr) and cultured in suspension. Leptin release from sc adipocytes was inhibited 17.7 +/- 5.2% (P < 0.01), 21.6 +/- 4.3% (P < 0.005), and 37.1 +/- 7.2% (P < 0.05) by 1, 10, and 100 ng/mL TNFalpha, respectively, after 48 h in culture. At 100 ng/mL, significant inhibition of leptin release (25.8 +/- 9.7%; P < 0.05) was detected by 24 h. TNFalpha (10 ng/mL) had no effect on dexamethasone (0.1 micromol/L)-stimulated leptin production in sc adipocytes. In omental adipocytes TNFalpha inhibited leptin release 21.0 +/- 9.6% and 40.8 +/- 6.3% at 10 and 100 ng/mL by 48 h (P < 0.05). Significant inhibition ofleptin release from omental adipocytes was observed at 24 h with 100 ng/mL TNFalpha (P < 0.05). Anti-TNFalpha antibody completely blocked TNFalpha inhibition of leptin release. The ob messenger ribonucleic acid was significantly reduced (23.6 +/- 5.9%) after 48 h of TNFalpha (100 ng/mL) treatment (P < 0.025). TNFalpha had no effect on glucose uptake or lactate production in sc and omental adipocytes. The data suggest that the direct paracrine effect of adipose-derived TNFalpha is inhibition of leptin production.

Vietnamese-speaking injecting drug users in Melbourne: the need for harm reduction programs

While research on aspects of injecting drug use (IDU), including injecting and sexual risks for HIV transmission, has been progressing in 'mainstream' Australian populations, there has been little among non-English speaking background (NESB) communities in Australia, particularly the South-East Asian communities, of which the Vietnamese is the largest. This exploratory study employed and trained peer workers to recruit and interview IDUs of Vietnamese origin in Melbourne on a wide range of subjects related to risks associated with their drug using, as an initial assessment of risk-taking behaviours for blood-borne viruses among Vietnamese-speaking IDUs. A finger-prick blood sample was taken where possible to measure antibody status to HIV, HBV and HCV. The profile which emerged was not dissimilar to that of their English-speaking counterparts prior to the benefit of currently available harm-reduction programs. A relatively isolated group whose social world often related only to other Vietnamese-speaking drug users, they were engaging in unsafe sex and unsafe injecting and were unfamiliar with procedures for cleaning injecting equipment and where they could seek out information and services, including needle exchanges. This study has identified an urgent need not only to promote currently available information and services to this group, but also to provide culturally relevant education and other harm-reduction measures needed to prevent transmission of HIV, other BBVs and STDs. The study has highlighted the lack of responsiveness of mainstream health services to the needs of Vietnamese-speaking IDUs.

Preliminary Identification of Maize Stripe Tenuivirus in Thailand

Maize stripe tenuivirus (MStV) and its planthopper vector, Peregrinus maidis, occur in many tropical and subtropical regions worldwide (2). However, MStV has not been reported from the southeastern Asia continent. In January 1990, five of 200 Sorghum bicolor plants growing in Hat Yai, Thailand, showed symptoms typical of MStV, i.e., chlorotic spots, streaks, and wide bands on the younger leaves. Colonies of P. maidis also were present in leaf whorls of both symptomatic and asymptomatic sorghum plants. In December 1991, two sweet corn plants (Zea mays cv. Thai Super Sweet Composite 1 DMR) growing in the same area showed similar symptoms and were infested with P. maidis. When examined by phase-contrast microscopy, sap from chlorotic leaf tissue of one sweet corn plant had needle-shaped crystals typical of MStV infection (1). Sap from asymptomatic sweet corn plants had no crystals. In April 1996. maize cv. Chieng Mai 90 with MSt-like symptoms and also infested by P. maidis was collected from Hat Yai. Leaves were freeze dried, sent to Ohio, and tested by F(ab')2 enzyme-linked immunosorbent assay (ELISA). Positive control samples were fresh or freeze-dried leaves of sweet corn infected with MStV from Australia, Costa Rica, Malawi, Mauritius. and the U.S. Leaves of asymptomatic glasshouse-grown sweet corn seedlings were negative controls. In the ELISAs, the OD values at A ₄₀₅ of the Thailand sample with MStV symptoms was 1.00, compared with 0.33 to 1.52 for the positive control samples and 0.00 to 0.02 for fresh or freeze-dried negative controls. The microscopic and serological results indicate the occurrence of MStV in Thailand. References: (1) O. E. Bradfute and J. H. Tsai. Phytopathology 80:715, 1990. (2) R. E. Gingery et al. J. Gen. Virol. 64:1765, 1983.

The first hit: circumstances surrounding initiation into injecting

Initiation into injecting is a crucial event for continued reproduction of an injecting drug using (IDU) population and for exposure to blood-borne viruses, but little is known about how this happens. Three hundred young injectors were interviewed in Melbourne by peer workers within the first few years of beginning to inject, about the circumstances surrounding their initiation. Most had indications of social disruption, including having left school early, unemployment, family disruption, homelessness and incarceration. First drug injected was most often amphetamines (average age 16 years), most having already used amphetamines by a different route of administration, but with a steady movement thereafter to heroin as the drug of choice. The most common scenario was one in which injecting was unplanned but the person was active in bringing about the initiation. Most identified a significant other who initiated them (few of whom were dealers), and over half had subsequently initiated others into injecting, on average 0.6 per year; after 5 years 237 young injectors had initiated at least 420 others. Those who initiated multiple others were more likely to be unemployed, to inject multiple drugs and to have dealt. Modelling injecting as a communicable phenomenon, where appropriate, may help estimate population dynamics among IDUs. Peer education programmes are likely to be the most effective harm reduction approach among new injectors.

An epidemiologic study of episodes of back pain care

STUDY DESIGN

This was a prospective community-based, observational design.

OBJECTIVE

To describe the epidemiology and risk/prognostic factors for back pain episodes of care in a population representing the nonelderly in the United States.

SUMMARY OF BACKGROUND DATA

Previous United States studies of the epidemiology of back pain care have used defined industrial populations or have relied on the patient's recall of symptoms and care.

METHODS

Claims forms from the RAND Health Insurance Experiment, a randomized controlled trial of the use of health services, were analyzed. Claims forms were selected if one of the patient-designated reasons for the visit was back pain. Visits were grouped into episodes of care. Descriptive statistics were calculated for episodes. Multivariate logistic regression was used to calculate adjusted odds ratios for independent explanatory sociodemographic and health status variables associated with back pain episodes of care.

RESULTS

The 3105 adults in the Health Insurance Experiment had a combined 11,171 person-years of exposure. Six-hundred-eighty-six persons (22%) had a total 1020 episodes of back pain care, representing 8825 visits. Seventy-one percent of persons had a single episode during the Health Insurance Experiment, and 40% of these episodes consisted of a single visit. There were 9.1 episodes per 100 person-years. Insurance status, geographic site, white race, lesser education, poorer physical functioning, and greater pain at base-line all were independently associated with having a back pain episode of care.

CONCLUSIONS

Back pain episodes of care occur commonly in the adult U.S. population, but usually are brief and recur infrequently.

Complex replication error causes p53 mutation in a Li-Fraumeni family

We demonstrated a germline p53 replication error in two generations of a Li-Fraumeni family affected with liposarcoma, adrenocortical carcinoma, and osteosarcoma. The trinucleotide repeat mutation changed 5'-AGT GTG GTG GTG-3' at codons 215-218 to 5'-AGT TGG TTG GTG GTG-3'. The predicted protein would be elongated by one amino acid (val216-->trp leu) without a change in charge. Detection of p53 in the adrenal tumor by immunostaining suggested that the mutant protein was expressed. Persistence of the mutation in the germline may suggest a defect in DNA repair in the family member first affected. This is the first report where germline transmission of replication-damaged p53 trinucleotide repeats is associated with the Li-Fraumeni syndrome.

Factors associated with choosing a chiropractor for episodes of back pain care

Back pain is a common illness and chiropractors provide a large proportion of back pain care in the United States. This is the first study to systematically compare chiropractic patients with those who saw other providers for back pain. The authors analyzed data from the RAND Health Insurance Experiment, a community-based study of the use of health services. Insurance claims forms were examined for all visits specified by the patient as occurring for back pain. Visits were grouped into episodes using decision rules and clinical judgment. The primary provider of back pain care was defined as the provider who delivered most of the services. Sociodemographic and health status and attitudes variables of patients were examined for association with the choice of chiropractor. Multivariate logistic regression models were constructed to calculate adjusted odds ratios for independent predictors. There were 1020 episodes of back pain care made by 686 different persons and encompassing 8825 visits. Results indicated that chiropractors were the primary provider for 40% of episodes, and retained as primary provider a greater percentage of their patients (92%) who had a second episode of back pain care than did medical doctors. Health insurance experiment site, white race, male sex, and high school education were independent predictors of choosing a chiropractor. Conclusions suggested that chiropractors were the choice of one third of all patients who sought back pain care, and provided care for 40% of all episodes of care. Geographic site, education, gender, and income were independent patient factors predicting chiropractic use.

Co-segregation of the maize dwarf mosaic virus resistance gene, Mdm1, with the nucleolus organizer region in maize

The mdm1 locus on the short arm of chromosome six confers resistance in maize to five strains of the maize dwarf mosaic virus (MDMV), an aphid transmitted potyvirus. The location of mdm1 in relation to RFLP and morphological loci on the short arm of chromosome six was determined using BC1 and F2 mapping populations. The following map order and distance in cM was obtained from the F2 population; jc1270-2.5-npi245-1.6-umc85/po1-0.5-mdm1/nor-0.5-bnl6.29A-0.5-npi235-0.8-npi101A-4.3-numc59. No recombination between mdm1 and the nucleolus organizer region (nor) was detected, as determined using a probe from the intergenic spacer region of the rDNA repeat. In order to resolve the relationship between mdm1 and the nor, and to recover recombinants around mdm1, a highresolution map within the polymitotic1 (po1) yellow kernel1 (y1) interval was generated using [po1 y1 tester (po1 mdm1 y1) x Pa405 (Po1 Mdm1 Y1)] F2 plants. The recessive po1 allele imparts a male-sterile phenotype when homozygous and since po1 and y1 are closely linked, the majority of fertile plants from white endosperm (y1/y1) F2 kernels will arise though a recombination event between the Pa405 Po1 allele and the y1 allele of the po1 y1 tester. Plants from 7,650 white (y1/y1) F2 kernels were examined (15,300 chromosomes) and a total of 626 F2∶3 recombinant families was recovered. Analysis of these recombinants revealed that mdm1 cosegregates with the nor. This lack of recombination between mdm1 and the nor suggests that: either (1) mdm1 is located in the region flanking the nor and recombination is suppressed within that region, or (2) mdm1 is located within the nor.

Comparing the costs between provider types of episodes of back pain care

STUDY DESIGN

This study was a prospective, community-based, observational design.

OBJECTIVES

The authors compared the costs of episodes of back pain care between different provider types in a population representative of the U.S.

SUMMARY OF BACKGROUND DATA

Previous comparisons between provider types of the costs for back pain care have been restricted to the worker's compensation population or have used something other than the episode as the unit of analysis.

METHODS

Data from the RAND Health Insurance Experiment (HIE) were analyzed. Insurance claims forms were examined for all visits specified by the patient as occurring for back pain. Visits were grouped into episodes using decision rules and clinical judgment. The primary provider was defined as the provider who delivered most of the care. Comparisons of costs between provider types were made.

RESULTS

There were 1020 episodes of back pain care made by 686 different persons and encompassing 8825 visits. Chiropractors and general practitioners were the primary providers for 40% and 26% of episodes, respectively. Chiropractors had a significantly greater mean number of visits per episode (10.4) than did other practitioners. Orthopedic physicians and "other" physicians were significantly more costly on a per visit basis. Orthopedists had the highest mean total cost per episode, and general practitioners the lowest. Chiropractors had the highest, and general practitioners the lowest mean outpatient cost per episode.

CONCLUSIONS

These are economically significant differences in the costs of back pain care of persons seeing chiropractors, general practitioners, internists, and orthopedists.

Occupation and lung cancer risk among women in northern China

Lifetime occupational histories were obtained in a case-control study of 965 female lung cancer patients and 959 controls selected from the general population in Shenyang and Harbin, People's Republic of China, where most women have worked outside the home. After adjusting for smoking, we found a significantly increased risk of lung cancer associated with employment involving the manufacture of transportation equipment (OR = 1.6, 95% CI = 1.0, 2.6), in particular the manufacturing of automobiles (OR = 3.0, 95% CI = 1.4, 6.4). Metal smelting and treatment workers were at an increased risk of lung cancer (OR = 1.5, 95% CI = 1.0, 2.1); the highest risks were observed among metal surfacers (OR = 3.1, 95% CI = 1.1, 9.0) and currently employed foundry workers (OR = 13.0, 95% CI = 1.7, 99.4). On the other hand, about a 50% decreased risk of lung cancer was observed among those employed in textile industries or as leaders of state and party organizations. Based on self-reports, exposures to coal dust and smoke from burning fuel at the workplace were also significant risk factors. The findings were similar when the analyses were confined to nonsmokers and were comparable across the major cell types of lung cancer.

The effect of amphotericin B, aztreonam, imipenem and cephalosporins on the bone marrow progenitor cell activity

The effects of certain antibiotics on the colony forming activity of human bone marrow cells in semisolid methylcellulose medium in vitro and on murine BM cells in spleen colony forming units (cfu-s) in vivo were evaluated. Amikacin, gentamicin, piperacillin, co-trimoxazole and pentamidine had little or no effect on human bone marrow progenitor cell function; amphotericin B, aztreonam, ceftazidime and imipenem caused significant suppression of human colony forming unit-erythroid (cfu-e), burst forming unit-erythroid (bfu-e) and colony forming unit-granulocyte macrophage (cfu-gm) at both peak and trough serum concentrations. At molar equivalent concentrations ceftazidime, cefotaxime and cefoperazone caused significant decreases in human cfu-e, bfu-e and cfu-gm in vitro (P less than 0.01) and murine cfu-s in vivo (P less than 0.05); cefoxitin, cefuroxime, ceftizoxime and ceftriaxone did not suppress human bone marrow progenitor cell activity. Gentamicin, piperacillin and ceftriaxone had no effect on murine cfu-s formation. Further studies to evaluate the effect of these antibiotics on human bone marrow in vivo are suggested.

Caries prevalence in Head Start children, 1986-87

Since the early 1970s, caries prevalence among school-aged children in the United States has declined. It appears that a small percentage of the children experience most of the caries increment. In addition, a large proportion of children in the US who need dental care receive it. An important factor in the amount of treatment received by children is the socioeconomic status of the family. Data on caries prevalence among preschool populations are limited. The Head Start program serves low-income families in the US and offers a unique opportunity to look at individuals who may be at greater risk of health problems and may experience less access to health services. A survey of 1,796 three- to five-year old Head Start children from low-income families was conducted in 1986-87. Caries prevalence, baby bottle tooth decay prevalence and relative need for dental care are reported for fluoridated and non fluoridated communities in California, Hawaii, and Micronesia. The data reveal scores that are higher in the sample population than in five-year-olds in national surveys and among Head Start children in previous surveys.

Preventive dentistry. II. Periodontal diseases, malocclusion, trauma, and oral cancer

This is the second of two articles reviewing the recommendations of the US Preventive Services Task Force for interventions by physicians, nurses, and other clinicians to prevent the major oral diseases and conditions. Physicians and other health professionals should be aware of their many opportunities to assist in preventive oral health care and should take appropriate action in collaboration with the patient's dentist.

Preventive dentistry. I. Dental caries

Primary care physicians and nurses have numerous opportunities to assist in the prevention of dental caries, periodontal diseases, malocclusion, trauma to the mouth and teeth, and oral cancer. This is the first of two articles that provide background for the US Preventive Services Task Force recommendations for interventions by physicians, nurses, and other clinicians to prevent these oral diseases and conditions. Physicians and other health professionals are urged to be aware of these opportunities and to take appropriate action in collaboration with the patient's dentist.

Malignant nerve sheath tumor containing endocrine cells

A malignant nerve sheath tumor occurred in the thigh of a 29-year-old man who had the stigmata of von Recklinghausen's neurofibromatosis. Chondroid foci, rhabdomyoblasts, and mucus-containing acini were identified in the tumor. Argyrophil cells and somatostatin-immunoreactive cells were present in acinar epithelium. Endocrine type granules were found in epithelial cells on ultrastructural examination. This is an example of a so-called "glandular schwannoma" and is unique in that it contained somatostatin-immunoreactive cells. A neural crest derivation is suggested for this complex tumor.

Dental care in the People's Republic of China

In comparison to the living conditions that existed before 1949, the People's Republic of China (PRC) represents a remarkable story of achievement. Western knowledge about the PRC has recently increased by leaps and bounds as detente with the United States has allowed many Americans to witness the "awakening of the dragon." Many of the achievements have been in the development of a health care delivery system that uniquely addresses the needs of the most populous country. There are numerous reports on the advancements made in manpower development and deployment, infectious disease control, family planning and acupuncture anesthesia and therapy. Yet there is little information about dental care in China. Dental disease being an essentially preventable disease has an interesting status in the Chinese health care system which relies on prevention rather than cure. In September and October 1974, the author visited five cities in China, Kwangchou (Canton), Peking, Tientsin, Suchou, and Shanghai and the respective countrysides except for Tientsin. Though any account or description is certain to be but a glimpse of Hsin Hua (the New China), the story is worth being told even if it must be accomplished by small chapters contributed by many individuals. In this light, the author explores the following areas: dental manpower training, which in China has produced stomatologists, dental technicians and dental nurses; the oral health status of school age children, dental care delivery and facilities, and probably the most remarkable while at the same time provocative areas, acupuncture analgesia and therapy.