Functional heterogeneity of lymphocytic choriomeningitis virus-specfic T lymphocytes. I. Identification of effector amd memory subsets.

At varying intervals after immunizing infections of adult BALB/c mice with lymphocytic choriomeningitis (LCM) virus, splenic lymphocytes were tested for their ability to either elicit acute LCM or protect against lethal intracerebral LCM virus challenge when transferred to syngeneic recipients that were, respectively, virus carriers induced by cyclophosphamide-induced immunosuppression and normal susceptible mice. These lymphocytes were also assayed for their capacity to lyse, in vitro, LCM virus-infected BALB 3T3 cells labeled with 51Cr. Only lymphocytes obtained from donor mice between 6 and 8 days postimmunization significantly protected normal recipients from the development of lethal central nervous system (CNS) disease when transferred 18-24 h before virus challenge. At 10 days they were not protective even though their cytolytic activity in vitro either exceeded or approximated that of protective lymphocytes. The capacity to protect more closely corresponded with a period of virus-induced DNA synthesis in donor spleens as measured by the incorporation of [5--125I]-2'-DEOXYURIDINe. However, none of these cytolytically active lymphocyte populations were effective in mediating acute CNS disease when transferred to virus-carrier mice. In contrast, lymphocytes obtained 18 days or later after primary immunization, although having no protective capacity and exhibiting minimal cytolytic activity in vitro, were able to regularly produce acute disease in virus-carrier mice. The ablation by anti-theta-serum treatment of these in vivo and in vitro virus-specific immune functions established that the relevant lymphoid cells were T lymphocytes. Similarly, reconstitution of C3H times C57BL F1 adult mice, depleted of lymphocytes by thymectomy and lethal irradiation, with syngeneic day 8 immune donor lymphocytes rendered them resistant to the development of the carrier state after intracerebral virus challenge; reconstitution of such animals with nonimmune lymphocytes restored their ability to develop typical LCM. Collectively, these data indicate that immunogenic stimulation with LCM virus leads to the development of at least two different virus-specific T-lymphocyte subsets: (a) an early appearing transient effector population of cells and, perhaps, their immediate precursors whose generation requires the presence of virus, and (b) a stable memory population that appears well after virus clearance and which has little or not no cytolytic activity. The possible mechanism by which these functionally different subsets can influence the outcome of acute or chronic LCM virus infections is discussed.

Ia antigens are the stimulating determinants in the syngeneic mixed lymphocyte reaction.

The murine syngeneic mixed lymphocyte reaction (sMLR) is a T cell proliferative response to self-antigens on non-T stimulator cells. The nature and specificity of the stimulating antigens was investigated using secondary MLR. Lymph node cells were stimulated in vitro by syngeneic spleen cells. After optimal proliferation occurred, the responding cell population was recovered and restimulated with spleen cells from mice of various haplotypes. The secondary response was found to be specific for the haplotype of the primary stimulator (a self-restricted response). The use of recombinant mice in the secondary stimulation localized the determinant to the I-A and/or I-E subregions of the major histocompatibility complex (MHC). This result was confirmed by the ability of monoclonal antibodies directed to the I-A or I-E subregion products to significantly inhibit the response while alloantiserum directed to products of the K or D regions had no effect.

Characterization of a new Marburg virus isolated from a 1987 fatal case in Kenya.

In 1987, an isolated case of fatal Marburg disease was recognized during routine clinical haemorrhagic fever virus surveillance conducted in Kenya. This report describes the isolation and partial characterization of the new Marburg virus (strain Ravn) isolated from this case. The Ravn isolate was indistinguishable from reference Marburg virus strains by cross-neutralization testing. Virus particles and aggregates of Marburg nucleocapsid matrix in Ravn-infected vero cells, were visualized by immunoelectron microscopic techniques, and also in tissues obtained from the patient and from inoculated monkeys. The cell culture isolate produced a haemorrhagic disease typical of Marburg virus infection when inoculated into rhesus monkeys. Disease was characterized by the sudden appearance of fever and anorexia within 4 to 7 days, and death by day 11. Comparison of nucleotide sequences for portions of the glycoprotein genes of Marburg-Ravn were compared with Marburg reference strains Musoki (MUS) and Popp (POP). Nucleotide identity in this alignment between RAV and MUS is 72.3%, RAV and POP is 71%, and MUS and POP is 91.7%. Amino acid identity between RAV and MUS is 72%, RAV and POP is 67%, and MUS and POP is 93%. These data suggest that Ravn is another subtype of Marburg virus, analogous to the emerging picture of a spectrum of Ebola geographic isolates and subtypes.

Filovirus activity among selected ethnic groups inhabiting the tropical forest of equatorial Africa.

Seroepidemiological surveys were conducted to determine the frequency and distribution of filovirus activity among selected ethnic groups inhabiting the tropical forests of the Central African Republic. 427 serum specimens were collected from hunter-gatherers and subsistence farmers living in forest environs in the Lobaye District south of the river Lobaye and west of the river Oubangui. Striking serological evidence for filovirus activity was found in both populations. Ebola virus appears to be the most active filovirus; 17.6% (75/427) of the Lobaye survey population were seropositive for Ebola virus reactive antibody while 1.2% (5/427) were seroreactive with Marburg viral antigens. Ethnic background appeared to be an important risk factor influencing filovirus exposure in the forest communities. The filovirus antibody prevalence among 21-40 years old male Aka Pygmy hunter-gatherers was significantly (P = 0.03) 3 times higher (37.5%) than that in similarly aged male Monzombo and Mbati subsistence farmers (13.2%). Continued epidemiological investigations are needed to define ethnic-related events influencing human filovirus activity in the Congo basin of equatorial Africa.

Haemorrhagic fever virus activity in equatorial Africa: distribution and prevalence of filovirus reactive antibody in the Central African Republic.

Seroepidemiological surveys were conducted to determine the frequency and distribution of haemorrhagic fever virus (HFV) activity in the Central African Republic. Human serum specimens (4295) were collected from 5 ecologically distinct zones. Serological evidence of HFV activity was found in all the zones. The filovirus antibody prevalence (24.4%, 1051/4295) was greater than the combined prevalence for Lassa virus, Rift Valley fever virus and Crimean-Congo HFV antibody (1.1%, 45/4295; P < 0.01). Evidence of filovirus activity was found in all zones: 21.3% (914/4295) of the population were seropositive for Ebola virus antibody while only 3.2% (137/4295) were seroreactive with Marburg viral antigens. Age and sex were important host-related factors influencing filovirus activity, particularly in dry grassland and moist forest communities. These communities shared many factors, but differences, such as agricultural practices and ethnic backgrounds, may also affect the risk of infection. Filovirus infections appear to occur without apparent disease. Continued investigations are needed to evaluate the true pathogenicity of the African filoviruses and the likelihood that unidentified serologically cross-reacting and non-pathogenic members of the filovirus family are active in equatorial Africa.

Some benchmark searches for testing search capabilities and medical coverage of internet discovery tools.

The past few years have seen a proliferation of search engines for the World Wide Web (WWW), as well as a growing number of specialized subject directories geared to the needs of health care professionals. Yet documentation on scope, coverage, and search features is often uneven at best; and even documented search features may not perform as advertised. This paper will present a group of sample searches to assist users in gauging database size, determining default search operators, and testing for the presence of advanced search features such as case sensitivity, stemming, and concept mapping for medical topics on English-language web sites.

Chemiluminescent detection of RFLP patterns in forensic DNA analysis.

DNA testing by restriction fragment length polymorphism (RFLP) analysis is an extremely important technique used in forensic science laboratories. While RFLP testing is a highly informative method, it traditionally has had several disadvantages. It is time consuming and involves work with radioactive phosphorous. A detection method that is faster and safer than isotopic detection is presented. Various membranes, fixation methods and transfer procedures were evaluated for DNA retention and sensitivity using alkaline phosphatase conjugated oligonucleotide probes and a chemiluminescent substrate. Blood samples and evidentiary material from forensic casework were analyzed by both chemiluminescent and isotopic detection. Results of each method were compared for pattern appearance, band size, and composite profile frequency. The chemiluminescent system had very good sensitivity, detecting 3-25 ng K562 DNA. Most patterns developed by both methods appeared the same. The variation observed between band sizes and frequency estimates generated by each method was as expected for an inter-gel comparison. The chemiluminescent detection procedure described here is suitable for use in forensic casework.

Detection of prostate specific antigen by ELISA.

A method for the detection of prostate specific antigen (PSA or P30) by enzyme linked immunosorbent assay (ELISA) has been developed. The method was evaluated for sensitivity and specificity and compared to other methods of semen identification on numerous casework samples. A sensitivity of less than 1 ng/mL PSA is routinely achieved. Numerous domestic contaminants and body fluids were tested and none were found to give a false-positive result. However, false-negative results did occur in samples contaminated with detergents. Additionally, some poorly preserved items of evidence did not give positive results where expected. In spite of these minor limitations, this method was found to be highly sensitive and specific and an efficient method for identifying semen in forensic casework.

Differences among families coping with serious mental illness: a qualitative analysis.

Families of 180 people with serious mental illness, representing various socioeconomic and ethnic groups, were interviewed about their understanding of their family member's illness, coping with problems caused by the illness, sources of support, effects of medication and substance abuse, and dealing with mental health professionals. Several significant areas of concern emerged, and are explored with attention to differences based on gender, ethnic group, socioeconomic status, and role of the family member.

Key roles for GRB2-associated-binding protein 1, phosphatidylinositol-3-kinase, cyclooxygenase 2, prostaglandin E2 and transforming growth factor alpha in linoleic acid-induced upregulation of lung and breast cancer cell growth.

The distribution of omega-6 and omega-3 polyunsaturated fatty acid (PUFA) intake in Western diets is disproportionate, containing an overabundance of the omega-6 PUFA, linoleic acid (LA; C18:2). Increased enrichment with LA has been shown to contribute to the enhancement of tumorigenesis in several cancer models. Previous work has indicated that phosphatidylinositol 3-kinase (PI3K) may play a key role in LA-induced tumorigenesis. However, the modes by which LA affects carcinogenesis have not been fully elucidated. In this study, a mechanism for LA-induced upregulation of cancer cell growth is defined. LA treatment enhanced cellular proliferation in BT-474 human breast ductal carcinoma and A549 human lung adenocarcinoma cell lines. Enrichment of LA increased cyclooxygenase (COX) activity and led to increases in prostaglandin E2 (PGE2), followed by increases in matrix metalloproteinase (MMP) and transforming growth factor alpha (TGF-α) levels, which are all key elements involved in the enhancement of cancer cell growth. Further investigation revealed that LA supplementation in both BT-474 breast and A549 lung cancer cell lines greatly increased the association between the scaffolding protein GRB2-associated-binding protein 1 (Gab1) and epidermal growth factor receptor (EGFR), although Gab1 protein levels were significantly decreased. These LA-induced changes were associated with increases in activated Akt (pAkt), a downstream signaling component in the PI3K pathway. Treatment with inhibitors of EGFR, PI3K and Gab1-specific siRNAs reversed the upregulation of pAkt, as well as the observed increases in cell proliferation by LA in both cell lines. A549 xenograft assessment in athymic nude mice fed high levels of LA exhibited similar increases in EGFR-Gab1 association and increased levels of pAkt, while mice fed with high levels of the omega-3 PUFA, docosahexaenoic acid (DHA; C22:6), demonstrated an opposite response. The involvement of Gab1 in LA-induced tumorigenesis was further defined utilizing murine cell lines that express high levels of Gab1. Significant increases in cell proliferation were observed with the addition of increasing concentrations of LA. However, no changes in cell proliferation were detected in the murine paired cell lines expressing little or no Gab1 protein, establishing Gab1 as major target in LA-induced enhancement of tumorigenesis.

Astrophysical reaction rate for the neutron-generator reaction 13C(alpha,n)16O in asymptotic giant branch stars.

The reaction 13C(alpha,n) is considered to be the main source of neutrons for the s process in asymptotic giant branch stars. At low energies, the cross section is dominated by the 1/2+ 6.356 MeV subthreshold resonance in (17)O whose contribution at stellar temperatures is uncertain by a factor of 10. In this work, we performed the most precise determination of the low-energy astrophysical S factor using the indirect asymptotic normalization (ANC) technique. The alpha-particle ANC for the subthreshold state has been measured using the sub-Coulomb alpha-transfer reaction ((6)Li,d). Using the determined ANC, we calculated S(0), which turns out to be an order of magnitude smaller than in the nuclear astrophysics compilation of reaction rates.

In search of applications of nursing theories: the Nursing Citation Index.

Cited author searches were conducted in Nursing Citation Index to determine its utility in locating clinical studies that apply the conceptual frameworks of Dorothea Orem, Callista Roy, Martha Rogers, Betty Neuman, and Dorothy Johnson. Fully 75 percent of the relevant papers would have been missed by a conventional subject/textword search in the MEDLINE or CINAHL databases. Had Nursing Citation Index not been available, only 22 percent of relevant papers could have been retrieved by cited author searches of Social Science Citation Index. In summary, Nursing Citation Index provides an important indexing link between nursing theory and nursing research.

Immune responses to LCM virus infection in vivo and in vitro. Mechanisms of immune-mediated disease.

Both recovery and death of mice following acute infections with lymphocytic choriomeningitis virus appear to be mediated by a population of virus-specific thymus-derived (T) effector lymphocytes that possess lytic activity in vitro against virus-infected syngeneic fibroblasts. Whether recovery or death occurs is determined by the balance between two interdependent factors: (1) the extent of virus-induced modifications in the surfaces of cells comprising "target" tissues, and (2) the efficiency of the immune inductive process leading to the generation of effector T lymphocytes that recognize and destroy these modified cells.

Thumb-sucking: literature review.

A multidisciplinary literature review of nonnutritive-sucking habits is presented. The causes, prevalence, and risks of these habits are discussed, and factors that contribute to the severity of the habit are identified.

Thumb-sucking: classification and treatment.

A new classification and treatment scheme is described that allows practitioners easy classification and appropriate treatment of a wide variety of nonnutritive-sucking habits. Summary classification and treatment reference tables are provided for convenient clinical reference.

Techniques of Online Citation Verification in NLM Databases.

This article is an exploration of techniques for identifying items in the health related literature using NLM system databases. Examples used are derived from reference desk and interlibrary loan files, but the techniques should be useful to any medical librarian who needs to verify a citation. A knowledge of NLM indexing practices and system commands is assumcd. Because of mace limitations the TOXLINE. TOXBACK74, TOXBACK65,AVLINE files have been omitted, but other bibliographic files and SERLINE are included. Tables designed for at-terminal use are presented.