IFN-gamma and LPS-mediated IL-10-dependent suppression of retinal microglial activation

PURPOSE

Human retinal microglia (MG) express constitutively major histocompatability complex (MHC) class II molecules and have thus been highlighted as potential immunocompetent antigen-presenting cells (APCs). This study was undertaken to characterize microglial expression of coaccessory molecules and the functional changes in antigen expression, cytokine production, migration, and phagocytosis after proinflammatory stimulation.

METHODS

Fresh donor retinal MG were obtained and isolated using a percoll density gradient technique. Phenotypic characteristics used for isolating rodent microglia were applied and modified. Coaccessory molecule expression and intracellular cytokine production were assessed using three-color flow cytometric analysis in both freshly isolated and interferon (IFN)gamma-lipopolysaccharide (LPS)-stimulated MG. Using five-millimeter retinal explants in culture, microglial migratory behavior, changes in cell surface antigen expression and phagocytic activity were documented.

RESULTS

MG could be clearly defined by the flow cytometric phenotype CD45low CD11b+ MHC class II+ CD86low CD40low. Freshly isolated MG showed mannose receptor-mediated uptake of dextran-FITC. MG migrated from explants, were adherent, and upregulated MHC class II expression. After IFNgamma-LPS stimulation of single-cell suspension of MG isolates, MHC class II expression was reduced, with an increase occurring in MG intracellular interleukin (IL)-10 and IL-10 production. Microglial migration from explants was reduced after IFNgamma-LPS stimulation.

CONCLUSIONS

These results highlight both phenotypic and behavioral characteristics that support an antigen-processing and -presenting capability of freshly isolated MG. However, proinflammatory stimulation with IFNgamma-LPS induces an IL-10-mediated downregulation of cell surface antigen expression and loss of migratory and phagocytic activity. Therefore, although equipped to act as APCs, MG are able to rapidly modulate their own function and behavior and as a result may have the potential to limit inflammation.

A randomized placebo-controlled double-blind trial of lipid-lowering strategies in patients with renal insufficiency: diet modification with or without fenofibrate

BACKGROUND

Renal insufficiency is characterized by lipoprotein abnormalities including elevated triglyceride levels.

PATIENTS AND METHODS

The safety and efficacy of micronized fenofibrate as a treatment for dyslipidemia in patients with progressive renal insufficiency was evaluated in a randomized, placebo-controlled double-blind study comparing fenofibrate and dietary modification to dietary modification alone. Patients were evaluated following a 3-month pre-randomization period of dietary counseling. Twenty-eight patients with moderate renal insufficiency and triglyceride levels 2.3 mmol/l or LDL/HDL ratio 5 were randomized to placebo (n = 12) or fenofibrate (n = 16) therapy. Treatment and dietary counseling continued for 6 months.

RESULTS

Ten of 16 patients (63%) treated with fenofibrate achieved a 30% reduction in triglyceride levels or LDL/HDL ratio reduction < 5 compared to 2 of 17% in the placebo group (p = 0.015). Triglyceride levels were significantly reduced in the fenofibrate group (-31%) versus placebo (+1.3%, p = 0.003). In compliant patients (n = 25) there was also a significantly greater increase in HDL cholesterol levels in the fenofibrate group (+19.9%) compared to placebo (-4.7%, p = 0.001). Changes in measured creatinine clearance were not significantly different between the groups and there were no serious adverse effects of treatment.

CONCLUSION

Fenofibrate therapy combined with dietary modification effectively reduced triglyceride levels in renal insufficiency patients without serious adverse effects.

Randomized, double-blind, placebo-controlled trial to evaluate the hematopoietic growth factor PIXY321 after moderate-dose fluorouracil, doxorubicin, and cyclophosphamide in stage II and III breast cancer

PURPOSE

To measure the effect of PIXY321 (granulocyte-macrophage colony-stimulating factor/interleukin-3 S. cerevisiae fusion protein) on the incidence, duration, and complications of neutropenia and thrombocytopenia after moderate-dose fluorouracil 600 mg/m(2), doxorubicin 60 mg/m(2), and cyclophosphamide 750 mg/m(2) (FAC) chemotherapy in patients with stage II and III breast cancer.

PATIENTS AND METHODS

In this multicenter, randomized, double-blind placebo-controlled trial, 71 women were to receive four 21-day cycles of treatment with moderate-dose FAC chemotherapy by short intravenous infusion on day 1, followed by either placebo or PIXY321 (375 microg/m(2) subcutaneously twice a day) on days 3 to 15. All patients were to receive prophylactic oral ciprofloxacin when the absolute neutrophil count was less than 1,000/microL.

RESULTS

PIXY321 significantly reduced the incidence and duration of grade 3 and grade 4 neutropenia in cycles 1 and 2 and the duration of grade 3 neutropenia in cycles 1 through 4. In cycles 3 and 4, grade 3 thrombocytopenia was significantly more common with PIXY321 (P <.05). Two patients, both in the PIXY321 group, required platelet transfusions. Fever and hospitalization for intravenous antibiotics were significantly more common in the PIXY321 group during cycle 1 only. More patients in the PIXY321 group achieved hematologic recovery by day 22 in cycles 1 through 3, and time to recovery was significantly shorter with PIXY321 in all cycles. FAC dose intensity was roughly 2% higher in the PIXY321 group (P = NS). Nonhematologic events of any intensity occurring with significantly greater overall frequency in the PIXY321 group included injection-site reactions, fever, chills, abdominal pain, and arthralgia. No patient died on study or within 30 days of her last dose of study drug.

CONCLUSION

PIXY321 decreased the incidence and duration of FAC-induced grade 3 and 4 neutropenia in cycles 1 and 2 and significantly shortened the time to hematologic recovery in all cycles. However, it produced more systemic toxicity as well as thrombocytopenia in cycles 3 and 4.

Fas-Fas ligand-mediated apoptosis within aqueous during idiopathic acute anterior uveitis

PURPOSE

Despite ocular immune privilege, (auto)immune-mediated acute anterior uveitis (AAU) is relatively common. However, although relapses of AAU are usually self-limiting, possible regulatory mechanisms remain undefined in humans. Experimentally, Fas-Ligand (FasL)-mediated apoptosis of Fas+ inflammatory cells contributes to the immune privilege within the anterior chamber and provides an explanation for the success of corneal allograft transplantation. Therefore, whether such mechanisms regulate the immune response in AAU was investigated.

METHODS

Aqueous and peripheral blood samples from consecutive patients presenting with idiopathic AAU were obtained with consent. Leukocytic phenotype was analyzed by flow cytometry, and apoptosis was determined by both flow cytometry and TdT-dUTP terminal nick-end labeling analysis. Presence of soluble Fas and FasL was determined by western blot analysis and enzyme-linked immunosorbent assay and compared with control aqueous from patients undergoing cataract surgery. The ability of the aqueous to induce apoptosis in a Fas+ Jurkat cell line was also determined.

RESULTS

During AAU aqueous-infiltrating Fas+ cells included CD3+ T cells and granulocytes, whereas FasL+ cells comprised predominantly of non-CD3+ T cells. Higher levels of functional soluble FasL were found in aqueous of AAU patients than in normal aqueous, capable of inducing apoptosis in 68.9% +/- 7.6% of Fas+ lymphoid cells. Compared with peripheral blood, the CD4+ T cells infiltrate within aqueous showed significantly increased CD69 and CD25(IL-2r) expression. Flow cytometric analysis of aqueous showed that 9.32% +/- 1.2% of infiltrating non-granulocyte CD45+ cells were apoptotic, confirmed as T cells on subsequent three-color flow cytometric analysis.

CONCLUSIONS

Taken together with published experimental data, the present study provides evidence for FasL-mediated apoptotic cell death contributing to the local immune regulation of ocular inflammatory disease and provides a mechanism to account for the self-limiting clinical course of AAU.

Regional differences in the sympathetic innervation of the guinea pig large intestine by neuropeptide Y- and tyrosine hydroxylase-immunoreactive nerves of divergent extrinsic origin

Region-specific patterns of nerves with immunoreactivity to neuropeptide Y (NPY) have been described previously in the submucous plexus of guinea pig large intestine. Because these may have functional significance, the possibility of similar, characteristic variations of NPY-like immunoreactivity (NPY-ir) in the myenteric plexus was explored. Regional differences were found in the occurrence and pattern of distribution of NPY-ir in the myenteric plexus of the guinea pig large intestine. NPY-ir was present rarely within neuron somata in any region of the large intestine, and NPY-ir nerve fibers were present only within the distal large intestine, increasing progressively in density from the distal spiral to the rectum. Lesion of the colonic nerves, but not the hypogastric, intermesenteric, or lumbar splanchnic nerves, resulted in a loss of NPY-ir in the distal spiral and transverse colon but not in the descending colon or rectum. Ring myotomies in the descending colon resulted in a loss of NPY-ir proximal to the lesion. Dual-labeling immunohistochemical studies revealed that the NPY-ir nerve fibers rarely contained immunoreactivity for tyrosine hydroxylase (TH). Extrinsic nerve lesions resulted in an unequivocal reduction in NPY-ir in intraganglionic fibers of the submucosal plexuses of the transverse colon and a partial loss in the distal spiral and descending colon: the rectum was unaffected; in only a minority of guinea pigs, however, was any decrease in the NPY-ir innervation of submucosal blood vessels detected. The principal projections of NPY-ir nerves were from and through the inferior mesenteric ganglion; however, NPY-ir was not colocalized with TH-ir. It is proposed that nonnoradrenergic, NPY-containing neurons located in the inferior mesenteric ganglion project through the colonic nerves and that these proximally directed fibers innervate the transverse colon and the distal spiral. Nonnoradrenergic, NPY-ir neurons lying in the pelvic ganglia or sacral sympathetic chain may make an important contribution to the innervation of the myenteric plexus of the rectum and the descending colon.

Intranasal administration of retinal antigens induces transient T cell activation and apoptosis within drainage lymph nodes but not spleen

Mechanisms of mucosal tolerance induction, including anergy/deletion and active suppression are frequently described as mutually exclusive; dependent upon nature, dose and route of antigen administration. We have previously described induction of low-dose tolerance with administration of retinal autoantigens via the nasorespiratory tract which is antigen-specific, suppresses both cell mediated immunity and ultimately tissue destruction in experimental autoimmune uveoretinitis (EAU) and is mediated by splenic-derived regulatory cells. The present data further shows that splenocytes or fractionated splenic T cells, which secrete IL-4 and IL-10 when stimulated with retinal antigen in vitro, and not regional drainage lymph node cells transfer tolerance to naïve animals. Analysis of apparent mechanistic differences shows that during intranasal antigen administration, the proportion of CD4(+)T cells within drainage lymph nodes increases, concurrent with a burst of IFN-gamma. Following subsequent antigen challenge, T cells downregulate alphabetaTCR expression and undergo apoptosis in regional drainage lymph nodes. An increase in functional Th2 cytokine activity was noted in both Con-A and retinal antigen stimulated lymph node cultures in tolerized animals. T cells from tolerized animals secreted IL-4, whereas IL-10 was secreted predominantly by the non-T cell population present equally in control and tolerized animals. Therefore, spleen derived regulatory cells which suppress Th1 responses and T cell deletion/apoptosis in regional drainage lymph nodes are mechanisms which co-exist in tolerant rats. Th2 cytokine production after immunization appears consequential to tolerance-induced Th1 suppression.

Sexual behaviour, STDs and drug use in a crack house population

We aimed to investigate the prevalence of ulcerative sexually transmissible diseases (STDs) and hepatitis in crack users. We interviewed 435 crack users on site in crack houses in Houston, Texas and took blood for laboratory analysis. There was evidence of syphilis infection in 13%, herpes simplex virus-2 (HSV-2) in 61%, HIV in 12%, hepatitis B in 52%, and hepatitis C in 41% of cases. On DSM-III-R criteria, 12% were crack abusers and 84% crack dependent: over half reported previous treatment. Forty per cent reported also injecting. Sexual behaviour indicated a mean of 2.4 partners in the past month for men, 3.7 for women. Sexual behaviour was largely vaginal, although women also reported more than twice the level of oral sex of men. Significant multivariate predictors for HIV and hepatitis B and C were previous reported STD and injecting drug use (including sharing needles), while female gender for syphilis and HSV-2, and additionally condom use for HSV-2, were significant risks. These data confirm high rates of STDs in a crack house population as inferred from previous clinic-based and community studies, and the link between STDs, injecting and HIV. The high rates of STDs found should lead to considering STDs and substance abuse to be dual diagnoses in crack users and the integration of STD diagnosis and treatment into crack outreach and treatment programmes.

Homocyst(e)ine and vascular access complications in haemodialysis patients: insights into a complex metabolic relationship

BACKGROUND

As elevated total homocyst(e)ine (tHcy) is associated with increased risk of vascular thrombosis, we hypothesized that the elevated levels of tHcy seen in patients on haemodialysis may be associated with an increased risk of thrombosis of native arteriovenous fistulae (vascular access failure). Our study was designed to investigate the relationship between tHcy and vascular access failure. The relationship between tHcy and mortality was explored as a secondary analysis.

METHODS

The study comprised a cross-sectional analysis of 96 haemodialysis patients at a single university-affiliated hospital and a subsequent 9-month prospective follow-up of 88 of the 96 patients.

RESULTS

Levels of tHcy (median 30 micromol/l) were elevated. In the initial cross-sectional sample, there was an inverse relationship between tHcy and history of vascular access failure which was not observed in the prospective study. Variables influencing the risk of vascular access failure in the prospective study included history of previous vascular access failure (RR=2.93, P=0.03), use of antiplatelet agents (RR=0.13, P=0.01), increased urea reduction ratio (RR=0.55 for a 5% increase, P=0.01) and increased weight (RR=0.61 for a 10 kg increase, P=0.02). Secondary analysis showed an unexpected inverse relationship between tHcy and mortality (RR=0.033 for 1 log increase in tHcy, P=0.006), such that the lower levels of tHcy were associated with an increased risk of death in short-term follow-up.

CONCLUSION

We did not demonstrate a relationship between tHcy and risk of vascular access failure. Patients with the lowest levels of tHcy appeared to be at increased risk of death in this short-term follow-up. The relationship of tHcy to vascular access complications and death in haemodialysis patients appears complex and requires further study.

Evidence for common sites of contact between the antisigma factor SpoIIAB and its partners SpoIIAA and the developmental transcription factor sigmaF in Bacillus subtilis

The activity of the developmental transcription factor sigmaF in Bacillus subtilis is governed by a switch involving the dual function protein SpoIIAB. SpoIIAB is an antisigma factor that forms complexes with sigmaF and with an alternative partner protein SpoIIAA. SpoIIAB is also a protein kinase that can inactivate SpoIIAA by phosphorylating it on a serine residue. We sought to identify amino acids in SpoIIAB that are involved in the formation of the SpoIIAB-SpoIIAA complex by screening for mutants that were defective in the activation of sigmaF. This genetic screen, in combination with biochemical analysis and the construction of loss-of-side-chain (alanine substitution) mutants, led to the identification of amino acid side-chains in the N-terminal region of SpoIIAB that could contact SpoIIAA. Unexpectedly, the same amino acid side-chains (R20 and N50) that appear to touch SpoIIAA are required for binding to, and may represent sites of contact with, sigmaF. We propose that the N-terminal region of SpoIIAB forms a binding surface that is responsible for the formation of both the SpoIIAB-SpoIIAA and the SpoIIAB-sigmaF complexes, and that in some cases the same amino acid side-chains contact both partner proteins. N50 is also the defining residue of a region of amino acid sequence homology known as the N-box that is shared by SpoIIAB and related serine protein kinases, as well as by members of a mechanistically dissimilar family of protein kinases that undergo autophosphorylation at a histidine residue. We discuss the implications of this finding for the mechanism of histidine autophosphorylation.

The kinase activity of the antisigma factor SpoIIAB is required for activation as well as inhibition of transcription factor sigmaF during sporulation in Bacillus subtilis

The activity of the developmental transcription factor sigmaF in the spore-forming bacterium Bacillus subtilis is controlled by SpoIIAB, which sequesters sigmaF in an inactive complex. sigmaF is released from the SpoIIAB-sigmaF complex by the action of SpoIIAA, which triggers the dissociation of the complex. SpoIIAB is also a protein kinase that phosphorylates SpoIIAA on serine residue 58 (S58). This phosphorylation inactivates SpoIIAA and thus indirectly prevents the activation of sigmaF. Here, we report the identification of a patch of amino acid residues located in the vicinity of the adenosine nucleotide binding pocket of SpoIIAB that is required for the phosphorylation of SpoIIAA. A lysine substitution (E104K) at one of these residues (Glu104) markedly impaired the capacity of SpoIIAB to phosphorylate SpoIIAA in vitro as well as during sporulation. Kinetic analysis and evidence from the construction of alanine substitution mutants indicates that the side-chains of these amino acids could be contact sites for the SpoIIAA substrate during the phosphorylation reaction. Importantly, E104K and other kinase mutants blocked the activation of sigmaF during sporulation. This is paradoxical, because a mutant of SpoIIAA (S58A) that cannot be phosphorylated is known to cause higher than normal levels of sigmaF activity during sporulation. In resolution of this paradox, we present biochemical evidence indicating that SpoIIAA directly attacks the SpoIIAB-sigmaF complex and that SpoIIAA is phosphorylated as a result of this reaction. Consistent with this idea, mutations impairing kinase function of SpoIIAB were found to be epistatic to a mutation causing the S58A substitution in SpoIIAA; that is, cells producing mutant forms of both proteins were blocked in the activation of sigmaF. We conclude that phosphorylation of SpoIIAA plays a dual role in the sigmaF pathway, and that the kinase function of SpoIIAB is required for the activation as well as the inhibition of sigmaF during sporulation.

Neutralizing TNF-alpha activity modulates T-cell phenotype and function in experimental autoimmune uveoretinitis

Inhibiting TNF-alpha activity prevents tissue destruction without inhibiting retinal T cell infiltration in experimental autoimmune uveoretinitis (EAU) in Lewis rats. To further determine the role of TNF-alpha in autoimmune uveitis we characterized T cells isolated from retinae after treatment with a TNF-alpha antagonist. TNF-alpha activity was neutralized in vivo with a p55 TNF-alpha receptor-Ig fusion protein (sTNFr-Ig), administered 8 and 10 days after induction of EAU with heterologous retinal antigens. Retinal T-cell phenotype expression was examined by flow cytometry with respect to OX22 status (CD45RBlow or CD45RBhigh), activation (OX40 and CD25 expression) and rate of T-cell apoptosis (Annexin V+PI- expression). Lymphocyte reactivity was assessed by proliferation responses and cytokine production to retinal antigens. Despite greater than 40% of CD4+ T cells being activated at the height of disease, the proportion of OX22low expression was reduced and T cells exhibited reduced IFN-gamma and elevated IL-4 production. Retinal T cells maintained antigen-specific proliferation and demonstrated a low apoptotic rate. Although in both animal groups, comparable numbers of T cells were isolated, neutralizing TNF activity suppressed Th1 effector mechanisms protecting against target organ damage.

Squamous cell carcinoma in a patient with chronic lymphocytic leukemia. An intraoperative diagnostic challenge for the Mohs surgeon

BACKGROUND

Chronic lymphocytic leukemia (CLL) is the most common form of chronic leukemia in the US. CLL patients have an increased risk of developing other malignant neoplasms, especially skin cancer. Lymphoma-associated squamous cell carcinomas (SCCs) tend to behave more aggressively and therefore are often treated with Mohs micrographic surgery (MMS).

OBJECTIVE

To elucidate the potential difficulty of distinguishing perineural infiltrates as leukemic infiltrates versus inflammatory infiltrates associated with SCC on frozen tissue sections during MMS.

METHODS

This is a case report illustrating a patient with CLL who develops a SCC on the posterior ear. MMS was employed to treat the patient. Special immunohistochemical stains were performed to help distinguish the type of perineural infiltrate present.

RESULTS

The perineural infiltrate was shown by immunohistochemistry to be leukemic in origin. Special stains for keratin revealed no residual SCC hidden in the infiltrate.

CONCLUSION

CLL is a malignancy that primarily effects the elderly population and markedly increases their risk of developing skin cancers, especially SCC. An intense infiltrate may be present surrounding the tumor. This case report demonstrates one of the potential challenges the Mohs surgeon may face in interpreting histologic frozen section. Immunohistochemistry may be helpful in providing a more definitive answer to this problem.

Combining tabular, rule-based, and procedural knowledge in computer-based guidelines for childhood immunization

IMM/Serve is a computer program which implements the clinical guidelines for childhood immunization. IMM/Serve accepts as input a child's immunization history. It then indicates which vaccinations are due and which vaccinations should be scheduled next. The clinical guidelines for immunization are quite complex and are modified quite frequently. As a result, it is important that IMM/Serve's knowledge be represented in a format that facilitates the maintenance of that knowledge as the field evolves over time. To achieve this goal, IMM/Serve uses four representations for different parts of its knowledge base: (1) Immunization forecasting parameters that specify the minimum ages and wait-intervals for each dose are stored in tabular form. (2) The clinical logic that determines which set of forecasting parameters applies for a particular patient in each vaccine series is represented using if-then rules. (3) The temporal logic that combines dates, ages, and intervals to calculate recommended dates, is expressed procedurally. (4) The screening logic that checks each previous dose for validity is performed using a decision table that combines minimum ages and wait intervals with a small amount of clinical logic. A knowledge maintenance tool, IMM/Def, has been developed to help maintain the rule-based logic. The paper describes the design of IMM/Serve and the rationale and role of the different forms of knowledge used.

Role of adenosine nucleotides in the regulation of a stress-response transcription factor in Bacillus subtilis

The RNA polymerase sigma factor sigma B is a stress-response regulatory protein in Bacillus subtilis. The activity of sigma B is controlled in part by RsbW, a protein that inhibits sigma B, and RsbV, a protein that counteracts this inhibition. We now demonstrate that purified RsbW is capable of forming alternative complexes with either sigma B or RsbV. Sigma B in the RsbW. sigma B complex was transcriptionally inactive. RsbV reversed this inhibition by sequestering RsbW in a RsbW-RsbV complex, thereby allowing sigma B to remain free and active. In contrast to interactions among the components of the homologous regulatory system for the sporulation transcription factor sigma F, the binding of RsbW to RsbV and sigma B did not require adenosine nucleotides. Experiments involving the exchange of proteins between the two regulatory systems demonstrated that RsbW and its homolog in the sigma F system, SpoIIAB, exhibit strong preference in binding to RsbV and sigma B, and SpoIIAA and sigma F, respectively, and that the difference in nucleotide-dependence of binding between these two systems is attributable to a difference between RsbW and SpoIIAB. In confirmation and extension of previous results, we show that RsbW is also a protein kinase that uses ATP to phosphorylate RsbV, thereby blocking the capacity of RsbV to bind to RsbW and activate transcription. A close correlation was observed between the concentration of ATP required for efficient RsbW-mediated phosphorylation of RsbV, inhibition of RsbW.RsbV comlex formation, and inhibition of sigma B-directed transcription. These results are consistent with the hypothesis that activation of sigma B under certain stress condition is due to a decrease in cellular ATP levels.

SpoIIAA governs the release of the cell-type specific transcription factor sigma F from its anti-sigma factor SpoIIAB

The Bacillus subtilis transcription factor sigma F is a cell-type specific regulatory protein whose activity is governed by SpoIIAB and SpoIIAA and the nucleotides ATP and ADP. SpoIIAB is an anti-sigma factor that binds to sigma F in a manner that is stimulated by ATP, thereby trapping sigma F in an inactive complex. Alternatively, SpoIIAB binds to SpoIIAA in a manner that is stimulated by ADP to form a SpoIIAB.SpoIIAA complex in which SpoIIAB is sequestered from sigma F. SpoIIAB is also a protein kinase that uses ATP to phosphorylate, and thereby inactivate, SpoIIAA. Thus, ATP inhibits sigma F activity both by promoting formation of the SpoIIAB.sigma F complex and by phosphorylation of SpoIIAA. In extension of previous results, we use affinity chromatography to show that SpoIIAB is capable of forming long-lived complexes with sigma F and SpoIIAA and that the formation of these complexes is dependent on ATP and ADP, respectively. Using a DNA template lacking adenosine residues on the non-transcribed strand, we demonstrate that ATP is required for SpoIIAB-mediated inhibition of sigma F-directed RNA synthesis and that this inhibition is prevented by SpoIIAA in a manner that is stimulated by ADP. We show that ADP acts by protecting SpoIIAA from phosphorylation by SpoIIAB and that a mutant protein bearing an amino acid substitution at the site of phosphorylation in SpoIIAA is capable of preventing the inhibition of sigma F in a manner that does not depend on ADP. A principal finding from the investigation is that SpoIIAA restores activity to sigma F that had previously been inhibited by SpoIIAB. This is demonstrated both by the capacity of SpoIIAA to reverse SpoIIAB-mediated inhibition of sigma F-directed RNA synthesis and by its capacity to interact with and disrupt the SpoIIAB. sigma F complex. The results are consistent with a model in which sigma F is controlled by the cellular concentration of unphosphorylated SpoIIAA.

Health practices among Russian and Ukrainian immigrants

Since 1990, due to political and legislative changes, immigration from the former Soviet Union to the United States has increased significantly. Population reports from 1988 indicate that there were approximately 406,000 Soviet immigrants in the United States at that time. This number is expected to increase due to the Immigration Reform Act of 1990, which raised the Soviet refugee ceiling to 50,000 per year. Currently, very little is known about the health status and health practices of this population, although some published data indicate that life expectancy and infant mortality rates compare poorly with those of the general population in the United States. Although the former Soviet republics experienced universal health care coverage, there was little emphasis on promoting a healthy lifestyle. Heavy cigarette use, high alcohol intake, poor dietary intake, little attention to physical fitness, and crowded living conditions have been described. Environmental pollution and poor occupational safety are common and have contributed to the health problems of the population. As the influx of immigrants continues, the consequences of these health conditions will impose a burden on health care services in this country. As with any immigrant group, an understanding of the potential health conditions and cultural values can facilitate appropriate medical care. This research was conducted to explore these issues. Interviews and a physical assessment were conducted with 30 adults from the former Soviet Union. The major health problems identified included various dental conditions requiring treatment, obesity, and the absence of basic health screening measures such as cholesterol testing, high blood pressure screening, Pap smears, and mammograms. The authors also identified a need for translators and for education regarding preventative self-care, such as breast self-examinations.

SpoIIE governs the phosphorylation state of a protein regulating transcription factor sigma F during sporulation in Bacillus subtilis

Cell-specific activation of the transcription factor sigma F during sporulation in Bacillus subtilis is controlled by a regulatory pathway involving the proteins SpoIIE, SpoIIAA, and SpoIIAB. SpoIIAB is an antagonist of sigma F, and SpoIIAA, which is capable of overcoming SpoIIAB-mediated inhibition of sigma F, is an antagonist of SpoIIAB. SpoIIAA is, in turn, negatively regulated by SpoIIAB, which phosphorylates SpoIIAA on serine 58. SpoIIAA is also positively regulated by SpoIIE, which dephosphorylates SpoIIAA-P, the phosphorylated form of SpoIIAA. Here, isoelectric focusing and Western blot analysis were used to examine the phosphorylation state of SpoIIAA in vivo. SpoIIAA was found to be largely in the phosphorylated state during sporulation in wild-type cells but a significant portion of the protein that was unphosphorylated could also be detected. Consistent with the idea that SpoIIE governs dephosphorylation of SpoIIAA-P, SpoIIAA was entirely in the phosphorylated state in spoIIE mutant cells. Conversely, overexpression of spoIIE led to an increase in the ratio of unphosphorylated SpoIIAA to SpoIIAA-P and caused inappropriate activation of sigma F in the predivisional sporangium. We also show that a mutant form of SpoIIAA (SpoIIAA-S58T) in which serine 58 was replaced with threonine was present exclusively as SpoIIAA-P, a finding that confirms previous biochemical evidence that the mutant protein is an effective substrate for the SpoIIAB kinase but that SpoIIAA-S58T-P cannot be dephosphorylated by SpoIIE. We conclude that SpoIIE plays a crucial role in controlling the phosphorylation state of SpoIIAA during sporulation and thus in governing the cell-specific activation of sigma F.

IMM/Serve: a rule-based program for childhood immunization

A rule-based program, IMM/Serve, is being developed to help guide childhood immunization for initial use, within Oregon. The program is designed primarily for automated use with an online immunization registry, but can also be used interactively by a single user. The paper describes IMM/Serve and discusses 1) the sources of complexity in immunization logic, 2) the potential advantages of a rule-based approach for representing that logic, and 3) the potential advantage of such a program evolving to become the standard of care. Related projects include 1) a computer-based tool to help verify the completeness of the logic, 2) a tool that allows a central part of the logic to be generated automatically, and 3) an approach that allows visualization of the logic graphically.