YB-1 DNA-binding protein represses interferon gamma activation of class II major histocompatibility complex genes.

Interferon gamma (IFN-gamma) is the most potent inducer of class II major histocompatibility complex (MHC) genes. This induction is uniquely mediated by three DNA elements in the promoter region of class II MHC genes. One of these DNA elements, Y, contains an inverted CCAAT box. Previously, we have screened a lambda gt11 library for Y-binding proteins and identified the YB-1 gene. Here we provide evidence that YB-1 can repress the IFN-gamma induction of class II MHC promoter as well as the Invariant chain (Ii) gene which also contains a Y element in its promoter. This was demonstrated by cotransfecting a YB-1 expression vector with promoter-reporter gene constructs. As an alternate approach, an efficient transient transfection system was developed which resulted in a > 70% transfection efficiency. Transfection of YB-1 by this procedure resulted in the near abrogation of IFN-gamma induced HLA-DR antigen and mRNA expression. These findings show the functional suppression of class II MHC gene induction by the YB-1 protein.

Phosphorylation coupled to the transfer of electrons from glutathione to cytochrome c.

Formation of adenosine diphosphate from adenosine monophosphate and inorganic phosphate can be coupled to the oxidation of reduced glutathione by cytochrome c in a reaction which requires oxidized glutathione as a catalyst. The reaction occurs with purified materials in tris(hydroxymethyl)aminomethane buffer and may represent the type reaction for one or more oxidative phosphorylations.

Irreversible block of the mycelial-to-yeast phase transition of Histoplasma capsulatum.

p-Chloromercuriphenylsulfonic acid (PCMS), a sulfhydryl inhibitor, prevented the mycelial-to-yeast transition of the dimorphic fungal pathogen, Histoplasma capsulatum. The effect of PCMS was specific for the mycelial-to-yeast transformation; it had no effect on growth of either the yeast or mycelial forms or on the yeast-to-mycelial transition. The failure of PCMS-treated mycelia to transform to yeast was permanent and irreversible. PCMS-treated mycelia could not infect mice but could stimulate resistance to infection by a pathogenic strain of Histoplasma capsulatum. These results suggest a new general strategy for vaccine development in diseases caused by dimorphic pathogens.

Correlation between pathogenicity and temperature sensitivity in different strains of Histoplasma capsulatum.

We compared the mycelial to yeast transitions of the Downs strain of Histoplasma capsulatum (low level of virulence) with those of G184A and G222B, two more virulent strains having different levels of pathogenicity for mice. When the morphological transitions are initiated by a temperature shift from 25 degrees to 37 degrees C, all three strains undergo similar physiological changes, but these are less severe in G184A and G222B than in the Downs strain. The transitions from mycelial to yeast morphology in both of the more virulent strains are also one-third more rapid than in Downs. We also find that the differences in temperature sensitivity of the three strains can be correlated with the temperature required for complete uncoupling of oxidative phosphorylation. The differences in sensitivity to elevated temperatures extend to the growth of yeast cells of all three strains. Considered together, our results suggest that sensitivity to elevated temperatures may be a key factor accounting for differences in virulence and that uncoupling of oxidative phosphorylation may be the primary event in the morphological transition in all three strains.

Radioimmunoassay for canine creatine kinase isoenzymes.

Antibodies specific for the B and M subunits of creatine kinase (ATP: creatine N-phosphotransferase, EC 2.7.3.2) isoenzymes were obtained by immunization of rabbits with canine BB and MM creatine kinase. A radioimmunoassay capable of measuring picomolar amounts of creatine kinase isoenzymes has been developed which measures concentrations of intact isoenzymes rather than activity. It should aid in elucidating the metabolism and breakdown of creatine kinase isoenzymes.

Effects of geriatric education on the attitudes of medical students.

This study investigated the effects of an educational program in geriatrics on the attitudes of a group of third-year medical students. A survey designed to measure attitudes toward geriatric patient care, aging, and older people was administered to all students before and after their participation in a 25-hour geriatrics education component of a Family Practice Clerkship. Results showed the students' attitudes were significantly improved following the geriatrics training program. Prior training in geriatrics and their specialty preference were also found to have an impact on attitude. The implications of the study for medical education and research are discussed.

Potential influences of residencies' health risk policies on their rankings by Ohio applicants.

Residents' health risks constitute an area of increasing concern for hospitals and residencies. This study examined the importance of health risk policies in the context of students' selection of residencies. In 1991, all 836 fourth-year students in six Ohio medical schools were surveyed about their attitudes regarding residencies' policies on drug screening, HIV (human immunodeficiency virus) testing, and smoke-free workplaces. Of 763 surveys able to be delivered, 341 (45%) were returned. Substantial subsets of the students indicated that they would rank lower or not at all a program that required pre-residency drug screening (22%) or HIV testing (31%). Conversely, almost half the students (48%) responded that they would rank a program higher whose institution has a smoke-free policy. A discussion of potential factors affecting these findings is presented, with recommendations for hospitals, residencies, and residency applicants.

Attributes conducive to learning in psychotherapy supervision.

Characteristics of future physicians and psychiatrists that are conductive to superior professional competency are possibly comparable to attributes that facilitate the learning of psychotherapy skills. For supervisors and supervisees, this article considers the usefulness of a list of ideal supervisee characteristics developed from a sampling of supervisor responses. Characteristics important in negotiating professional development stages are also discussed.

Protein expression profiling of normal and neoplastic canine prostate and bladder tissue.

Prostatic carcinoma is an important cancer in both men and dogs. Dogs have been a valuable animal model for investigating prostate cancer, but their relevance is unclear as the origin of canine prostatic carcinomas is unknown. We hypothesized that a proteomic approach for diagnosis of these neoplasms might provide quantitative data useful for more complete characterization of their origin. Protein expression profiles were prepared from normal canine prostate glands and bladders. The normal protein profiles were then compared with protein expression profiles of three canine prostatic carcinomas. Two-dimensional differential in-gel electrophoresis (2-D DIGE) was used to analyse an average of approximately 1000 proteins per carcinoma. When compared with normal prostate tissue, the carcinomas exhibited greater than 2.5-fold difference in expression for an average of 230 proteins. Similar proteomic comparisons between the carcinomas and the normal bladder revealed a greater than 2.5-fold difference in expression for an average of 208 proteins. Mass spectrometry and protein database homology were used to identify nine proteins (alpha-enolase, vimentin, GRP78, endoplasmin (GRP94), albumin, keratins 7 and 8, haptoglobin, and transferrin) overexpressed by the carcinomas. Statistical testing demonstrated that keratin 7, GRP78, and endoplasmin were significantly overexpressed in the carcinomas compared with normal prostate or bladder. Principal components analysis revealed that the carcinomas formed a unique cluster distinct from either the normal prostate or normal bladder. In conclusion, proteomic analysis revealed that whereas the majority of proteins expressed by canine prostatic carcinomas are also expressed by normal and neoplastic bladder and prostate tissue, the carcinomas contained unique protein components that allowed their segregation as a distinct group separate from normal canine prostate and bladder. Additionally, several proteins uniquely expressed by canine prostatic carcinomas were also identified.

Health visitor identification of postnatal depression.

Evaluation of a health visitor project in Sevenoaks demonstrated both the value of the Edinburgh postnatal depression scale (EPDS) in the identification of postnatal depression, and the positive benefit of health visitor intervention in its early stages. But, as Angela Painter reports, the project also underlined the need for a ten-week home visit and the obstacles presented by large caseloads, poor liaison with other services and purchaser reluctance.

Physician life-style management: a selective for first-year medical students.

A two-week selective is offered to medical students at the end of their first medical school year on physician life-style management. The primary objective of the selective is to enhance the quality of physician life-planning and to prevent physician disability. The course focuses on various aspects of physicians' life-styles, including practice management, health maintenance, marriage and the family, and physician disability and exposes students to actual physician practices and nonprofessional aspects of physician life-styles, for example, home life, hobbies, and civic involvement. The selective received high ratings from the students participating in the course and is believed to be helpful in the socialization of medical students into satisfying physician life roles.

Mycelial- to yeast-phase transitions of the dimorphic fungi Blastomyces dermatitidis and Paracoccidioides brasiliensis.

The physiological changes that occur during the mycelial- to yeast-phase transitions induced by a temperature shift from 25 to 37 degrees C of cultures of Blastomyces dermatitidis and Paracoccidioides brasiliensis can be divided into three stages. The triggering event is a heat-related insult induced by the temperature shift which results in partial uncoupling of oxidative phosphorylation and declines in cellular ATP levels, respiration rates, and concentrations of electron transport components (stage 1). The cells then enter a stage in which spontaneous respiration ceases (stage 2), and finally, there is a shift into a recovery phase during which transformation to yeast morphology occurs (stage 3). Cysteine is required during stage 2 for the operation of shunt pathways which permit electron transport to bypass blocked portions of the cytochrome system. The mycelial- to yeast-phase transitions of these two fungi are very similar to that of Histoplasma capsulatum. Therefore, these three dimorphic fungal pathogens have evolved parallel mechanisms to adjust to the temperature shifts which induce these mycelial- to yeast-phase transitions.

Morphogenesis and pathogenicity of Histoplasma capsulatum.

The sulfhydryl blocking agent p-chloromercuriphenylsulfonic acid (PCMS) irreversibly inhibited the mycelium-to-yeast transitions of two virulent strains of Histoplasma capsulatum, G184A and G222B, when the temperature of incubation was raised to 37 degrees C, and the block persisted even after the cultures were washed free of PCMS. Instead of transforming to yeast cells, PCMS-treated mycelia continued to grow as mycelia at the elevated temperatures. A less virulent strain (Downs) was more temperature sensitive, but it showed a similar irreversible effect at 34 degrees C. Therefore, the mycelium-to-yeast transition of H. capsulatum is not required for the adaptation of mycelia to elevated temperatures but probably results from the temperature-dependent activation of yeast-specific genes. The transition to yeast is inferred to be obligate for pathogenicity in mice because PCMS-treated mycelia failed to cause infection, and no fungi were seen in tissues after PCMS-treated mycelia were injected into mice.

Binding of phosphorylated Sp1 protein to tandem Sp1 binding sites regulates alpha2 integrin gene core promoter activity.

The alpha2beta1 integrin, a collagen/laminin receptor, is expressed by a variety of cell types, including epithelial cells, mesenchymal cells, and hematopoietic cells. To understand the molecular mechanisms that regulate expression of the alpha2beta1, integrin in cells with megakaryocytic differentiation, we characterized the 5' flanking region of the alpha2 integrin gene and identified three distinct regulatory regions, including a core promoter, a silencer, and megakaryocyte enhancers in the distal 5' flank (Zutter et al, Blood 96:3006, 1995 and Zutter et al, J Biol Chem 269:463, 1994). We now focus on the core promoter of the alpha2 integrin gene located between bp -30 and -92 that is required for transcriptional activity of the alpha2 integrin gene. Sequence analysis identified two Sp1 consensus sites and a potential AP2 site. Gel retardation assays showed that nuclear proteins from uninduced K562 cells and K562 cells induced to become megakaryocytic bound specifically to the core promoter region (bp -30 to bp -92) producing two DNA-protein complexes. In addition, nuclear extracts from cells induced along the megakaryocyte lineage produced a selective increase in the slower migrating complex. Site-directed mutagenesis of the 5', the 3', or both Sp1 binding sites suggested that both Sp1 binding sites are required for full promoter activity and for DNA-protein complex formation. DNA footprinting also showed specific protection of the 5' Sp1 site by nuclear extracts from uninduced K562 cells and protection of both the 5' and the 3' Sp1 sites by nuclear extracts from induced K562 cells. Sp1 protein-DNA complex formation was dependent on Sp1 phosphorylation. The faster migrating DNA-protein complex was enhanced by dephosphorylation; the slower migrating DNA-protein complex was diminished or lost.

Family practice undergraduate education.

A survey conducted by the Wright State University School of Medicine indicates that family practice has become a fully integrated curriculum component in the majority of US medical schools. Results indicate that family practice courses are offered most often as outpatient experiences and are taught by both full-time and volunteer faculty.

The Megakaryocyte/Platelet-specific enhancer of the alpha2beta1 integrin gene: two tandem AP1 sites and the mitogen-activated protein kinase signaling cascade.

The alpha2beta1 integrin, a collagen receptor on platelets and megakaryocytes, is required for normal platelet function. Transcriptional regulation of the alpha2 integrin gene in cells undergoing megakaryocytic differentiation requires a core promoter between bp -30 and -92, a silencer between bp -92 and -351, and megakaryocytic enhancers in the distal 5' flank. We have now identified a 229-bp region of the distal 5' flank of the alpha2 integrin gene required for high-level enhancer activity in cells with megakaryocytic features. Two tandem AP1 binding sites with dyad symmetry are required for enhancer activity and for DNA-protein complex formation with members of the c-fos/c-jun family. The requirement for AP1 activation suggested a role for the mitogen-activated protein kinase (MAPK) signaling pathway in regulating alpha2 integrin gene expression. Inhibition of the MAP kinase cascade with PD98059, a specific inhibitor of MAPK kinase 1, prevented the expression of the alpha2 integrin subunit in cells induced to become megakaryocytic. We provide a model of megakaryocytic differentiation in which expression of the alpha2 integrin gene requires signaling via the MAP kinase pathway to activate two tandem AP1 binding sites in the alpha2 integrin enhancer.

Regulation of alpha 2 integrin gene expression in cells with megakaryocytic features: a common theme of three necessary elements.

The alpha 2 beta 1 integrin mediates interactions between cells and the extracellular matrix molecules, collagen and/or laminin. The alpha 2 beta 1 integrin is expressed in a variety of cell types, but in cells of hematopoietic lineage, expression is restricted to megakaryocytes and platelets. Increased expression of the alpha 2 beta 1 integrin during megakaryocytic differentiation is a consequence of transcriptional activation of the alpha 2 gene. We have begun to characterize the role of the 5' flanking region of the alpha 2 integrin gene in regulating expression during megakaryocyte differentiation. A 5-kb fragment of the 5' region directs both cell type and differentiation-dependent expression of a reporter gene in the pluripotent hematopoietic K562 cells upon megakaryocytic differentiation and in the megakaryocytic cell line, Dami. Analysis of a series of 5' deletion mutants indicates that expression of the alpha 2 integrin gene in cells with megakaryocytic features requires a core promoter region, a silencer region, and megakaryocytic enhancers in the distal 5' end. The organization of these three distinct regulatory regions of the alpha 2 promoter/enhancer suggests a common theme for megakaryocytic gene regulation shared with other megakaryocyte-specific proteins, including alpha IIb integrin subunit and platelet factor 4.

Variable expression of a yeast-phase-specific gene in Histoplasma capsulatum strains differing in thermotolerance and virulence.

By means of differential hybridization techniques, several yeast-phase-specific DNA sequences were identified in the dimorphic pathogenic fungus Histoplasma capsulatum. A 1.85-kilobase (kb) HindIII fragment from one genomic clone, yps-3, hybridized to at least three distinct yeast poly(A)+ RNAs of 1.3, 1.05, and 0.95 kb from the virulent strain G217B. These mRNAs were not detected in mycelia. When mycelia from G217B were induced to become yeast by transfer from 25 to 37 degrees C, a process requiring approximately 9 days, expression of yps-3 was detected within 24 h, although not in the initial 2 h following the temperature shift. In contrast, a low-virulence strain (Downs) which completes the transition in approximately 2 weeks failed to express the yps-3 gene during phase transitions. A third isolate, G186B, intermediate in its virulence properties and in the time required for the transition (11 days), expressed a single 1.25-kb mRNA but only at low levels in the yeast phase and only after 3 days following the 25-to-37 degrees C temperature shift. Although yps-3 expression does not appear to be essential for the transformation to the yeast phase, it may facilitate the early adaptive processes which permit the mycelium-to-yeast transition and survival of the yeast phase of H. capsulatum at elevated host temperatures. The phase-specific yps-3 nuclear gene is carried on highly polymorphic restriction fragments in all three strains, suggesting that this probe may provide a sensitive diagnostic tool for the classification of H. capsulatum isolates.

Possible relationship of morphogenesis in pathogenic fungus, Histoplasma capsulatum, to heat shock response.

Histoplasma capsulatum, like many other fungal pathogens, is dimorphic: it exists as mycelia in the soil and yeast in animal hosts. Because only the yeast phase is parasitic, factors which affect morphogenesis have been of interest for understanding and controlling pathogenicity. In culture, the mycelial to yeast transition of H. capsulatum is induced by a temperature shift from 25 to 37 degrees C (ref. 1). The transition occurs over several days and is accompanied by marked changes in metabolic processes, including respiration and cysteine metabolism. Here, we show that the triggering event for these morphological and biochemical changes is a rapid decline in intracellular ATP levels that follows uncoupling of oxidative phosphorylation when mycelia are shifted from 25 to 37 degrees C. We also show that respiration in the yeast phase is coupled at 37 degrees C and thus that the morphological transition may be viewed as a heat shock followed by cellular adaptation to higher temperature.

Family physicians and referral for psychotherapy.

This study examines the factors influencing family physicians' patient referrals for psychotherapy. A questionnaire designed from a pilot study of the full-time family practice faculty at Wright State University was mailed to all members (154) of the voluntary family practice faculty at Wright State University with a 63 percent return rate. Results indicated the most important factors in determining whether a patient is referred for psychotherapy include the severity of the problem, the threat of suicide, and the need for specialized treatment. The most important therapist characteristics looked for by a family physician are ability, availability, appreciation of the person as a whole, interaction skills, and experience. The article also discusses the ways in which family physicians find a psychotherapist, the feedback desired by the family physician from a psychotherapist, and type of psychotherapist discipline preferred by the family physician for handling various patient situations.