Point prevalence of secretory otitis media in children in southern Vietnam

Few reliable data exist on the prevalence of secretory otitis media (SOM) in the Third World. A large epidemiologic cross-sectional study was undertaken in two communes in southern Vietnam to study an urban and a rural community during two different climatic conditions: the dry and rainy seasons. The participants included 3,300 children (6,598 ears) ages 6 months to 10 years. Otolaryngological and medical histories were obtained, and an otolaryngological examination was carried out on 1,669 children in April 1995 (the dry season) and on 1,631 children in December 1995 (the rainy season). Tympanograms were obtained (n = 6,055), 429 of which were type B curves. The overall prevalence of SOM was 7.1%, the highest incidence was at the age of 2 years (with a prevalence of 22%), and there was a significantly higher prevalence of SOM during the rainy season than during the dry season. No significant difference in incidence was found in the urban district as compared to the rural district.

The impact of the quantity of skeletal injury on mortality and pulmonary morbidity

OBJECTIVE

To determine if the quantity of skeletal injuries (and the timing to fixation) increases the mortality or pulmonary morbidity in patients with and without chest injuries.

DESIGN

Retrospective analysis of trauma registry. Statistical analysis with multiple logistic regression and chi(2) analysis.

METHODS

Looking specifically at adult patients (> 16 years), skeletal injury was quantified by determining the presence or absence of a fracture in specific body regions (humeri, forearm, femur, tibia, spine, and pelvis) for a maximum of 10 skeletal injuries. The timing of fixation for fractures was categorized as < 24 hours, < 48 hours, < 72 hours, < 5 days, > 5 days, or no fixation. Chest injuries and pulmonary morbidity were based on the accepted list of complications reported in the literature.

RESULTS

Three groups were analyzed according to the presence or absence of a chest or skeletal injury: those without skeletal injury (group NSI, n = 59), those without chest injuries (group NCI, n = 108), and those with both skeletal and chest injuries (group B, n = 59) Pulmonary Complications: When all patient groups (NCI, NSI, and B) were pooled, greater chest injury (p < 0.0008), greater skeletal injury (p < 0.02), and delayed fixation (p < 0.04) were associated with increased risk of developing a pulmonary complication. In the group of patients without a chest injury (NCI), this risk was associated with greater head injury (p < 0.005) and greater skeletal injury (p < 0.04), whereas in the group without a skeletal injury (NSI), only chest injury demonstrated significance (p < 0.05). When both skeletal and chest injuries were present, greater head injury (p < 0.03) and fixation time (p < 0.03) increased the risk of developing a pulmonary complication. Mortality: With all patients pooled (NCI, B, and NSI), head injury (p < 0.02), abdominal injury (p < 0.012), and fixation time (p < 0.01) were risk factors. In patients without a chest injury (NCI), none of the indexed variables were associated with mortality. In patients without a skeletal injury (NSI), greater head injury (p < 0.01), greater chest injury (p < 0.01), and greater abdominal injury (p < 0.04) were risk factors for mortality. When both chest and skeletal injuries were present (B), only head injury (p < 0.0003) was associated with mortality. The prevalence of mortality and pulmonary complications were compared between groups NCI, NSI, and B. Group NCI had fewer pulmonary complications (p < 0.004) than the other groups (difference not significant). When examining mortality, group NCI had less mortality than groups NSI and B.

CONCLUSION

The combination of skeletal and chest injuries does not seem to amplify the pulmonary morbidity and mortality compared with chest injury alone. The quantity of the skeletal injury and the time to fixation of structures affecting mobilization seem to have an effect on pulmonary morbidity and mortality. Better scientific studies on the effects of skeletal injury and timing to fixation in relation to pulmonary morbidity and mortality are required.

Semaphorin III can repulse and inhibit adult sensory afferents in vivo

During development, semaphorins (collapsin, fasciclin) mediate repulsive and inhibitory guidance of neurons. Semaphorin III, a secretable member of this family, is expressed by the ventral spinal cord at the time corresponding to projection of sensory afferents from the dorsal root ganglion (DRG) into the spinal cord. The inhibitory effect of E14 ventral cord is active only on nerve growth factor (NGF)-responsive sensory afferents (small-diameter A-delta and C fibers subserving sensations of temperature and pain). Similarly, COS cells secreting recombinant semaphorin III are able to selectively repel DRG afferents whose growth is stimulated by NGF and not NT-3. However, it is not known whether these molecules can exert a functional role in the fully developed adult peripheral nervous system. In this study, we demonstrated that gene gun transfection and production of semaphorin III in corneal epithelial cells in adult rabbits in vivo can cause repulsion of established A-delta and C fiber trigeminal sensory afferents. In addition, it is shown that, following epithelial wounding and denervation, semaphorin III is able to inhibit collateral nerve sprouts from innervating the reepithelialized tissue. These findings are significant in that they provide direct evidence that small-diameter adult sensory neurons retain the ability to respond to semaphorin III. In addition, the corneal gene gun technique may be generally used to study the in vivo effects of neural growth modulators by quantifying the amount of sensory nerve growth.

Does debulking surgery improve survival in biologically aggressive ovarian carcinoma?

Aggressive tumor reduction surgery has been widely used in patients with advanced stage epithelial ovarian carcinoma before initiation of cytotoxic chemotherapy. No randomized controlled trial has been carried out to confirm the benefits of such procedures. To examine the role of cytoreductive surgery in the management of stage 2 and 3 patients with epithelial ovarian carcinoma treated with postoperative adjuvant platinum-based chemotherapy, survival analysis was carried out on patients with initial microscopic disease documented on staging laparotomies, patients with large volume of disease at time of exploration and tumor reduced to microscopic residuals, and patients who were suboptimally debulked with more than 2-cm residual disease. Twenty-four, 81, and 191 patients were identified from a computerized data base, respectively. Kaplan-Meier survival estimates showed that 62% with initial microscopic residual are alive with no evidence of disease at 5 years and 56% of patients left with microscopic residuals after tumor reduction are alive and well at 5 years. There was no statistical significant difference between these two groups. The groups are equivalent with respect to known adverse prognostic factors. In contrast, 5-year survival in the suboptimal debulked group was significantly lower at 15%. Debulking surgery to achieve microscopic residual disease improved the prognosis in patients with initial large volume of disease. Survival was similar to survival in patients with microscopic disease at time of exploration. The beneficial effect may be attributed to the removal of chemoresistant clones in bulky tumors. Tumor reduction surgery remains important in the management of advanced stage epithelial ovarian carcinoma.

Utility of magnetic resonance imaging in a patient with anomalous origin of the right coronary artery, acute myocardial infarction, and near-sudden cardiac death

A 46-year-old female presented with an acute myocardial infarction and cardiac arrest. Coronary angiography revealed an anomalous origin of the right coronary artery coursing between the aorta and pulmonary artery. Magnetic resonance imaging confirmed the life-threatening nature of this anomaly and led to referral for surgical revascularization.

Controlled gene gun delivery and expression of DNA within the cornea

Selective delivery of genes to ocular tissues in vivo has been a long sought after goal for potential gene therapy of ocular disease. The gene gun was considered for this purpose because of its ability to focally transfer DNA to cells through gold microparticles coated with DNA. Through experimentation, we optimized a technique that allows focal delivery and expression of a plasmid encoding green fluorescent protein in the corneal epithelium 100% of the time. Though the corneal epithelium has a delicate structure, this introduction was not associated with any corneal or ocular damage and did not produce any apparent ocular irritation. These findings demonstrate the utility of gene gun delivery of DNA to selected ocular tissues for potential experimental and therapeutic purposes.

Effects of retinoid X receptor-selective ligands on proliferation of prostate cancer cells

BACKGROUND

Management of prostate cancer that either is detectable by prostate specific antigen (PSA) measurements after curative intent or has spread outside of its capsule is a serious problem. Innovative, nontoxic approaches to the disease are required. One approach might be therapy with retinoids. Retinoid activities are mediated by two distinct families of transcription factors: the retinoic acid receptors (RARs) and retinoid X receptors (RXRs), which can induce transcriptional activation through specific DNA sites or by inhibiting the transcription factor AP-1 that usually mediates cellular proliferative signals. The RARs require heterodimerization with RXRs. RXRs can form either heterodimers or homodimers; and the latter can bind to DNA response elements that are distinct from those bound by the RAR/RXR heterodimers.

METHODS

A series of novel synthetic retinoids that selectively interact with RXR/RXR homodimers or RAR/RXR heterodimers, or that selectively inhibit AP-1 activity without activating transcription were evaluated for their ability to inhibit clonal growth of three human prostate cancer cell lines (PC-3, DU-145, and LNCaP).

RESULTS

Several notable findings were: 1) RXR-selective retinoids, such as SR11246, were able to inhibit the clonal growth of prostate cancer cells. In contrast, SR11246 had little effect on clonal growth of myeloid leukemic cells. 2) RAR-selective retinoids also inhibited clonal growth of prostate cancer cells. 3) The retinoid (SR11238) with potent anti-AP-1 activity had no effect on the clonal growth of prostate cancer cells.

CONCLUSIONS

This study shows that both RXR- and RAR-selective retinoids are worthy of further study and may be candidates for future clinical trials in prostate cancer.

Regulation of interleukin-10 gene expression: possible mechanisms accounting for its upregulation and for maturational differences in its expression by blood mononuclear cells

Interleukin-10 (IL-10) downmodulates phagocytic immune responses and accentuates humoral responses. Human neonates exhibit broad immune deficits that parallel actions of IL-10. We postulated that IL-10 production would be diminished in neonatal blood cells. We found that IL-10 production by lipopolysaccharide-stimulated peripheral blood mononuclear cells (PBMNCs) in vitro was greater by adult cells than by term cells and preterm cells. Additional studies were undertaken to identify mechanisms responsible for the developmental differences in IL-10 gene expression. IL-10 transcription was present in freshly isolated adult and neonatal cells in the absence of detectable levels of transcript. Transcription rates were not different between adult and neonatal cells. IL-10 transcripts were approximately 40% more abundant in adult cells than in term cells and were consistent with differences in secreted protein; however, no differences were noted in mRNA stability. IL-10 half-life was 60 minutes for both adult and term PBMNCs. We conclude that up-regulation of IL-10 gene expression in PBMNCs is modulated at the post-transcriptional level, that IL-10 protein production and mRNA content are greater in activated cells from adults compared with those from neonates, and that maturational differences in IL-10 expression are not due to differences in transcription rate or mRNA stability. Maturational differences in IL-10 expression might be due to differences in subpopulations of cytokine-producing cells or differences in nucleo-cytoplasmic transport.

Malignant mixed mesodermal ovarian tumor treatment and prognosis: a 20-year experience

Mixed mesodermal sarcoma of the ovary is a rare clinical entity. To review the epidemiology, prognostic factors, and treatment results related to primary ovarian sarcoma at our center, a retrospective chart review of all patients referred for ovarian cancer was carried out from 1974 to 1994. Cases with confirmed pathologic diagnosis of primary mixed mesodermal ovarian sarcomas were selected, forming the present study group. Thirty-six charts were identified. The median age at presentation was 67.5 years. Findings at laparotomy demonstrated extraovarian metastasis in 33/35 patients. Total abdominal hysterectomy and bilateral salpingo-oophorectomy +/- omentectomy were performed in 34 patients, with 22 patients left with macroscopic residual disease after surgery. Follow-up adjuvant chemotherapy consisting of cisplatin and doxorubicin was administered to 29/36 patients. Follow-ups ranged from 1 to 11 years with a median of 2 years. As with epithelial ovarian cancer, residual disease after initial surgery is an important prognostic factor. Thirteen patients had a second-look laparotomy. Five patients were positive for disease. Eight patients, one of whom recurred, were histologically negative. The patients with positive second-look findings, as well as all those who recurred clinically, subsequently died within 12 months despite trials with different second-line chemotherapeutic agents. Survival analysis showed a median survival of 3 years among patients treated with combination cytotoxic chemotherapy. Primary ovarian sarcomas make up about 2-3% of all ovarian cancer cases seen in our center. These are often very aggressive tumors with widespread metastasis at the time of presentation, making optimal tumor debulking difficult. The combination of cisplatin and doxorubicin appears to have activity resulting in a survival of 35% at 5 years. Second-look surgery offers little helpful information on the management of these tumors.

Hypothalamic nitric oxide synthase is depressed in cholestatic rats

We examined hypothalamic nitric oxide synthase (NOS) levels and release as well as steady-state mRNA levels in rats with cholestasis due to bile duct resection (BDR) and in sham-resected control rats. BDR rats had a significant reduction in hypothalamic NOS-containing neurons in the hypothalamic paraventricular nucleus as determined by NADPH-diaphorase staining, compared with sham-resected controls. In addition, NOS activity, measured indirectly by determining nitrite release from hypothalamic explants, was significantly lower in BDR rats compared with sham-resected animals. Hypothalamic steady-state NOS mRNA levels [brain constitutive NOS (bNOS)] were determined by semiquantitative reverse transcription-polymerase chain reaction and were found to be increased 1.5-fold in BDR rats compared with sham rats. In summary, BDR rats have diminished hypothalamic NOS levels and activity coupled with enhanced steady-state bNOS mRNA levels, suggesting that depressed hypothalamic NOS protein levels are due to posttranscriptional defects.

Antigen presentation by autoreactive proteolipid protein peptide-specific T cell clones from chronic progressive multiple sclerosis patients: roles of co-stimulatory B7 molecules and IL-12

To assess the role of T cell antigen (Ag) presentation in multiple sclerosis (MS), proteolipid protein (PLP) peptide reactive CD4+ T cell clones (TCCs) from MS patients and normal subjects were studied. TCCs derived from chronic progressive (CP) MS patients were able to proliferate and secret cytokines in response to PLP peptide stimulation in the absence of professional antigen presenting cells (APCs), suggesting that these T cells can simultaneously present and respond to Ags. However, they did not respond to total PLP protein, suggesting that PLP-peptide TCCs were unable to process and present the whole PLP molecule. The ability of the different TCCs to act as APCs in response to Ag stimulation did not correlate with expression of HLA-class II molecules. However, the degree of expression of B7-1 and B7-2 co-stimulatory molecules showed a significant correlation with APC capacity. Furthermore, a combination of anti-B7-1 and anti-B7-2 mAbs effectively inhibited proliferative responses as well as secretion of IL-10, IFN gamma and TGF beta induced by antigen presenting T cells. By contrast, IL-4 secretion was not affected. Finally, IL-12 significantly enhanced the efficiency of T cell Ag presentation by a pathway independent of Ag processing, suggesting that IL-12 might act as an additional co-stimulatory signal for T cell activation during T-T cell interactions. Together, these observations suggest that Ag presentation by T cells might amplify and perpetuate an autoimmune response previously initiated by professional APCs. These properties may account for progression of MS into a CP phase.

Preferential radiosensitization of G1 checkpoint-deficient cells by methylxanthines

PURPOSE

To develop a checkpoint-based strategy for preferential radiosensitization of human tumors with deficient and/or mutant p53.

METHODS AND MATERIALS

A549 human lung adenocarcinoma cell lines differing in their expression of the p53 tumor suppressor gene were produced by transduction with the E6 oncogene from human papilloma virus type 16. The cells expressing E6 (E6+) lack a G1 arrest in response to ionizing radiation, are deficient in p53 and p21 expression, and exhibit a fivefold greater clonogenic survival following 10 Gy radiation.

RESULTS

Postirradiation incubation with millimolar concentrations of the methylxanthine pentoxifylline (PTX) results in preferential radiosensitization of the E6+ cells compared to the LXSN+ vector transduced controls. There is a threefold sensitization of the LXSN+ cells and a 15-fold sensitization of the E6+ cells, which results in equal clonogenic survival of the two lines. Flow cytometry reveals PTX abrogation of the radiation induced G2 arrest for both cell lines. PTX also prolongs G1 transit for both cell lines. Preliminary results are presented using a novel methylxanthine, lisofylline (LSF), which has similar cell cycle effects on G1 and G2 and achieves differential radiosensitization at micromolar concentrations that are sustainable in humans.

CONCLUSION

This checkpoint-based strategy is a promising approach for achieving preferential radiosensitization of p53- tumors relative to p53+ normal tissues.

An analysis of sampling errors for the Demographic Health Surveys

"Sampling errors and design effects from 48 nationally representative surveys conducted under the Demographic and Health Surveys Program for a large number of variables concerning fertility, family planning, fertility intentions, child health and mortality etc. are analysed for the total sample, and for urban-rural domains, sub-national regions and various demographic and socio-economic subclasses.... At the country level, overall design effect (the ratio of actual to simple random sampling standard error) averaged over all variables and countries is around 1.5. Variation among countries is high, but less so than among variables. Urban-rural and regional differentials in design effects are small, and can be attributed to the fact that similar sample designs and cluster sizes were used across those domains within each country. Design effects for estimates over other subclasses are smaller, and tend towards 1.0 for small subclasses and differences, apart from the effect of sample weights which tends to persist undiminished across variables and subclasses." (SUMMARY IN FRE)

Health care access and preventive care among Vietnamese immigrants: do traditional beliefs and practices pose barriers?

Some have speculated that underutilization of Western health services among non-Western populations can be explained by traditional health beliefs and practices rooted deep within cultures. These beliefs and practices may act as barriers to access to and utilization of services. Among Vietnamese, in particular, a number of traditional health beliefs and practices have been identified which are said to pose barriers to Western medical care. No studies to date, however, have examined this hypothesis empirically. To examine this hypothesis, we measured traditional health beliefs and practices among Vietnamese in the San Francisco Bay area and analyzed the relationships between these factors and access to health care and use of preventive health services. The results of this study show clearly that many Vietnamese possess traditional health beliefs and practices which differ from those of the general U.S. population. Yet, the data do not support the hypothesis that these traditional beliefs and practices act as barriers to access to Western medical care or to utilization of preventive services. Being married and poverty status were the most consistent predictors of health care access. Furthermore, the components of access to health care (having some form of health insurance or having a regular doctor, for example) were the strongest predictors of preventive health care services utilization. Importantly, the cultural attributes of individuals did not explain either lack of health care access or underutilization of preventive health care services.

Functional and physical interactions between the Epstein-Barr virus (EBV) proteins BZLF1 and BMRF1: Effects on EBV transcription and lytic replication

The Epstein-Barr virus (EBV) proteins BZLF1 and BMRF1 are both essential for lytic EBV replication. BZLF1 is a transcriptional activator which binds directly to the lytic origin of replication (oriLyt) and plays a critical role in the disruption of viral latency. The BMRF1 protein is required for viral polymerase processivity. Here we demonstrate that the BMRF1 gene product functions as a transcriptional activator and has direct (as well as indirect) interactions with the BZLF1 gene product. The BMRF1 gene product activates an essential oriLyt promoter, BHLF1, but does not activate two other early EBV promoters (BMRF1 and BHRF1). Direct interaction between the BMRF1 and BZLF1 gene products requires the first 45 amino acids of BMRF1 and the bZip domain of BZLF1. The effect of the BZLF1-BMRF1 interaction on early EBV transcription is complex and is promoter specific. The oriLyt BHLF1 promoter is activated by either the BZLF1 or BMRF1 gene product alone and is further activated by the combination of the BZLF1 and BMRF1 gene products. Enhanced activation of BHLF1 transcription by the BMRF1-BZLF1 combination does not require direct interaction between these proteins. In contrast, BZLF1-induced activation of the BMRF1 promoter is inhibited in the presence of the BMRF1 gene product. A point mutation in the BZLF1 protein (amino acid 200), which prevents in vitro interaction with the BMRF1 protein but which does not reduce BZLF1 transactivator function, allows the BZLF1 protein to activate the BMRF1 promoter equally well in the presence or absence of the BMRF1 gene product. Therefore, direct interaction between the BZLF1 and BMRF1 proteins may inhibit BZLF1-induced transcription of the BMRF1 promoter. BZLF1 mutated at amino acid 200 is as efficient as wild-type BZLF1 in promoting replication of an oriLyt plasmid. However, this mutation reduces the ability of BZLF1 to induce lytic replication of the endogenous viral genome in D98/HE-R-1 cells. Our results indicate that functional and physical interactions between the BMRF1 and BZLF1 proteins may modulate the efficiency of lytic EBV infection. The BMRF1 gene product clearly has a transcriptional, as well as replicative, role during lytic EBV infection.

Phylogenetic characterization of the epithelial Na+ channel (ENaC) family

Twenty-one sequenced protein members of the epithelial Na+ channel (ENaC) family have been identified and characterized in terms of their sizes, hydropathy profiles, sequence similarities and phylogenies. These proteins derive from mammals, the frog Xenopus laevis and the worm Caenorhabditis elegans. The eleven sequenced vertebrate proteins fall into four subfamilies designated alpha, beta, gamma and delta. The 10 C. elegans proteins do not cluster with the vertebrate proteins, and they all proved to be distantly related to each other. Nonetheless, the 21 ENaC proteins exhibit the same apparent topology, each with two transmembrane spanning segments separated by a large extracellular loop. All but two ENaC proteins possess highly conserved extracellular domains containing numerous conserved cysteine residues as well as adjacent C-terminal amphipathic transmembrane spanning segments, postulated to contribute to the formation of the hydrophillic pores of these oligomeric channel protein complexes. It is proposed that the well-conserved extracellular domains serve as receptors to control the activities of the channels. A topological model for the ENaC family proteins is presented.

Pattern of utilization of rifabutin for prophylaxis of Mycobacterium avium complex among patients with advanced human immunodeficiency virus disease in a community setting

OBJECTIVE

To characterize the pattern of utilization, effectiveness, and safety profile of rifabutin for Mycobacterium avium complex (MAC) prophylaxis among individuals with advanced human immunodeficiency virus disease in a community setting.

METHODS

Individuals who, while registered in the provincial drug distribution program, had at least one CD4 count below 100 cells/mm3 for the period 1 May 1993 to 31 March 1994 were included. MAC diagnoses were identified through a record linkage with the mycobacterial reference laboratory of the Provincial Centre for Disease Control. In order to determine the occurrence of adverse events, a survey was sent in March 1994 to the 98 primary care physicians prescribing rifabutin prophylaxis in the province. We achieved 100% response rate to the survey.

RESULTS

During the study period 515 patients in our drug treatment program were eligible to receive MAC prophylaxis. Of these, 340 (66%) were being prescribed rifabutin as recommended by current guidelines. Rifabutin prophylaxis use was significantly associated with use of antiretroviral therapy. The product limit estimate of the cumulative incidence of MAC at 10 months was 13.0% among those receiving rifabutin prophylaxis. Diagnosis of MAC was significantly associated with a lower baseline CD4 count (cumulative incidence 7.1% and 18.1% for CD4 > or = 50 and < 50 cells/mm3, respectively, P = 0.01). A total of four cases of uveitis, eight cases of pseudo-jaundice, and five cases of arthralgia in 16 patients were identified by our survey.

CONCLUSION

Our data demonstrates that rifabutin prophylaxis of MAC is being used by approximately 66% of eligible individuals. Rifabutin use was associated with antiretroviral use, which may reflect individuals' attitudes towards medications. Our intention-to-treat analysis, with a 10 month cumulative MAC incidence of 13.0% among those receiving rifabutin prophylaxis, is in keeping with break-through rates previously reported in the context of clinical trials. Our results also support previous observations that the risk of MAC infection greatly increases at CD4 counts < 50 cells/mm3. Rifabutin prophylaxis was generally well-tolerated in our program.

Radioiodinated (aminostyryl)pyridinium (ASP) dyes: new cell membrane probes for labeling mixed leukocytes and lymphocytes for diagnostic imaging

We prepared [125I/131I]iodo-(aminostyryl)pyridinium dyes from tributylstannyl precursors. ASP 7a and 7b labeled leukocytes ex vivo (70-94%) using saline with or without washing plasma from cells. Viability of peripheral blood lymphocytes (PBLs) (dogs, rats) and splenic lymphocytes (rats) labeled with 7a and 7b (71-82%) was unchanged after labeling (> or = 88%). Canine 7b-leukocytes showed higher uptake in inflammatory lesions than did 111In-oxine leukocytes. At 3 h, aspirates contained more radioiodine than 111In (1.65:1 to 22:1) and radioiodine was cell bound. ROI measurements (3 h) gave abscess to contralateral knee ratios of 12.3 and 10.6 for 131I-7b vs. 4.8 and 2.3 for 111In-oxine.

Bryostatin 1 acts synergistically with interleukin-1 alpha to induce secretion of G-CSF and other cytokines from marrow stromal cells

The protein kinase C (PKC) activator bryostatin 1 (bryo) has substantial antileukemic and hematopoietic actions. Bryo promotes the in vitro growth of normal hematopoietic progenitors by inducing the release of growth factors from accessory cells. We have examined the effects of bryo on the expression and release of certain myeloid growth factors from fibroblastlike marrow stromal cells (MSC). Substantial release of granulocyte colony-stimulating factor (G-CSF), granulocyte-macrophage colony-stimulating factor (GM-CSF). or interleukin-6 (IL-6) following bryo treatment was seen only in MSC cultures contaminated with macrophages. Bryo alone was ineffective in inducing release of the cytokines from MSC cultures containing only fibroblastlike stromal cells. When MSC were treated with IL-1alpha, substantial quantities of the cytokines (G-CSF, GM-CSF,IL-6) were released. Bryo acted synergistically with IL-1 alpha to significantly increase cytokine release to- to nine-fold compared to IL-1alpha alone (p < 0.016). Neither Il-1alpha nor bryo, alone or in combination, induced release of stem cell factor (scf) from MSC. The synergistic interaction between IL-1alpha and bryo was dose- and schedule-dependent, requiring simultaneous application of IL-1alpha and bryo for optimum effect. Bryo alone induced no G-CSF mRNA accumulation but increased the level seen with IL-1alpha treatment by 50%. The synergistic interaction of bryo and IL-1alpha required PKC, since it was antagonized by agents which depleted or inhibited PKC but not by a protein kinase A antagonist. The increase in G-CSF mRNA was associated with a marked increase in mRNA stability. Bryostatin may promote the release of cytokines from several accessory cell populations, including MSC, to accomplish its in vivo hematopoietic effects.

Identification of a putative steroidogenic factor-1 response element in the DAX-1 promoter

The nuclear hormone receptor, DAX-1, is responsible for X-linked adrenal hypoplasia congenita and hypogonadotrophic hypogonadism. We recently cloned the 5' flanking region of the human DAX-1 gene and in this report we describe the identification of a putative steroidogenic factor 1 (SF-1) response element approximately 110 bases upstream of the TATA box. Both DAX-1 and SF-1 are expressed in similar tissues including the adrenal cortex, gonads, hypothalamus, and the pituitary gland. Like DAX-1, SF-1 expression has been shown to be essential for the development of the adrenal cortex. We demonstrate that SF-1 is able to efficiently bind to the putative SF-1 response element found in the DAX-1 promoter in vitro. This suggests that SF-1 may directly regulate the expression of DAX-1 and that these two transcription factors may be components of a cascade required for development of steroidogenic tissues.

Use of pooling and outpatient laboratory specimens in an anonymous seroprevalence survey of HIV infection in British Columbia, Canada

OBJECTIVE

To conduct an anonymous HIV seroprevalence survey to establish a baseline estimate of HIV seroprevalence in a general population; to evaluate serum pooling and alternative testing strategies as cost-saving measures.

DESIGN

Prospective anonymous HIV seroprevalence study using outpatient laboratory specimens.

SETTING

Two large non-hospital-associated outpatient chemistry testing laboratories in the major population centers in British Columbia, Canada. PATIENTS AND SERA: Leftover sera received for chemistry screen testing in outpatient laboratories were provided to the study after chemistry testing was completed. Those from patients aged < 15 and > or = 55 years were excluded.

METHODS

Patient identifiers were erased from samples. Sera were pooled 10:1 and tested by viral lysate enzyme-linked immunosorbent assay (ELISA). Sera from HIV-positive pools were tested individually. All individual HIV-positive specimens were retested for verification of positivity using a recombinant protein ELISA.

MAIN OUTCOME MEASURES

HIV seroprevalence rates were stratified by sex, age group, and geographic area; and costs of pooling and alternative algorithm strategy were compared with those of conventional methods.

RESULTS

A total of 80,238 sera were collected from 66,658 individuals (53% women, 47% men). Of these, 276 men (88.3 per 10,000) and 24 women (6.8 per 10,000) were HIV-seropositive. The highest rates were in those aged 30-34 years, for both men and women. Using pooling and non-Western blot verification saved US$2.07 per specimen, or 80% of the cost for conventional testing.

CONCLUSIONS

The anonymous outpatient laboratory setting is practicable to obtain a reasonable estimate of HIV seroprevalence rates in a general population. Such studies can be made cost-effective by pooling sera and using alternative confirmatory strategies.

Hapten-induced chronic colitis in the rat: alternatives to trinitrobenzene sulfonic acid

Hapten-induced colitis is a widely used model for the study of the intestinal inflammation and for the testing of novel therapies. However, the hapten utilized in this model, trinitrobenzene sulfonic acid, is difficult to obtain in some countries. We therefore compared this hapten to two structurally related haptens to determine if they could be substituted for trinitrobenzene sulfonic acid in terms of inducing chronic colitis in the rat. Rats received one of the three haptens intracolonically, and the severity of colonic inflammation was assessed 3 and 14 days later. Dinitrobenzene sulfonic acid produced colonic inflammation and ulceration that was indistinguishable from that induced by trinitrobenzene sulfonic acid at both time points. On the other hand, dinitrochlorobenzene produced acute colitis (3 days postadministration), but by Day 14 this inflammation had subsided. Dinitrobenzene sulfonic acid and trinitrobenzene sulfonic acid produced comparable levels of granulocyte infiltration into the colon (as measured by tissue myeloperoxidase activity and histology) at both time points. These studies suggest that for studies of up to at least 2 weeks in duration, dinitrobenzene sulfonic acid and trinitrobenzene sulfonic acid produce comparable levels of colonic inflammation. Dinitrobenzene sulfonic acid therefore offers a useful and less expensive alternative to trinitrobenzene sulfonic acid.

Crystallization of the chaperone protein SecB

The secretory protein SecB found in Escherichia coli is a molecular chaperone that binds to precursor forms of a number of proteins targeted for export to the periplasmic space. SecB maintains these proteins in a translocation-competent conformation facilitating the translocation process. The material has been cloned and expressed in E. coli. Crystals have been grown from polyethylene glycol 8000 by vapor diffusion using the hanging drop technique. These crystals are monoclinic, belonging to space group C2 with unit cell dimensions a = 56.0 A, b = 111.1 A, c = 134.7 A, and beta = 104 degrees. The crystals diffract to 8 A resolution on a Rigaku imaging plate detector. Dynamic light scattering experiments suggest that SecB exhibits aggregation behavior with a number of different precipitating agents. These results may explain resistance of SecB to forming ordered crystals.

Isolation and characterization of autoreactive proteolipid protein-peptide specific T-cell clones from multiple sclerosis patients

During the course of multiple sclerosis (MS), myelin proteins are likely antigenic targets for autoreactive T cells. Although most studies have implicated myelin basic protein as a potent encephalitogenic myelin component, proteolipid protein (PLP) appears also to be a possible target antigen in the autoimmune response in MS. In this report, we investigated the human T-cell responses to PLP by using PLP104-117 and PLP142-153 synthetic peptides as target antigens in limiting dilution. One hundred twenty-five CD4+, T-cell receptor (TCR) alpha beta+ T-cell clones (TCCs) were established from the peripheral blood of seven MS patients and five control subjects. Despite the use of enriched cultures no gamma delta TCCs were obtained. Recognition of both PLP epitopes occurred in the context of multiple HLA-DR alleles. We found no differences in restriction element usage between MS patients and control subjects. TCR variable beta-region (V beta) usage was assessed by flow cytometry using a panel of monoclonal antibodies defining different V beta elements. In both MS patients and control subjects, there was a marked heterogeneity in the TCR V beta repertoire. Furthermore, sequential evaluation of MS patients during acute attacks and clinical remissions showed even more broadening of the TCR V beta repertoire. These data demonstrate that a heterogeneous T-cell response to PLP concerning HLA restriction and TCR usage is present in both MS patients and normal subjects.

Patterns of cytokine secretion by autoreactive proteolipid protein-specific T cell clones during the course of multiple sclerosis

To determine whether cytokine secretion patterns change with disease status in patients with multiple sclerosis (MS), we measured IFN-gamma, TNF-alpha beta, IL-4, IL-6, IL-10 and TGF-beta secretion in a panel of T cell clones (TCCs) specific for proteolipid protein (PLP) after stimulation with PLP peptides or polyclonal activators. During acute attack, the predominant pattern of cytokine secretion resembled that of murine Th1 cells; i.e, IFN-gamma and TNF-alpha beta, and appeared to be restricted to PLP-reactive TCCs. None of the TCCs isolated during acute attack produced TGF-beta in response to PLP, Con A, or anti-CD3 Ab. Half of these TCCs were, however, capable of TGF-beta secretion and mRNA expression upon stimulation with PMA and the calcium inonphore A23187, suggesting a possible defect in activation through the TCR/CD3 pathway. During remission in the same patients all but two PLP-TCCs showed patterns of cytokine secretion resembling that of murine Th0, Th1, and Th2 subsets. The levels of IL-10 secreted by these TCCs were significantly higher than those of TCCs isolated during acute attacks and those derived from normal subjects and patients with other noninflammatory neurologic diseases. Furthermore, 50% of these TCCs were capable of producing TGF-beta after Ag-specific or polyclonal stimulation. All TCCs isolated from control subjects exhibited a Th0 like secretion profile. These data indicate that different stages of disease in MS are characterized by different patterns of cytokine secretion by PLP-specific TCCs, suggesting a role for cytokines in clinical events during the course of MS.