Bcl-3 expression and nuclear translocation are induced by granulocyte-macrophage colony-stimulating factor and erythropoietin in proliferating human erythroid precursors

Bcl-3 is a proto-oncogene involved in the chromosomal translocation t(14;19) found in some patients with chronic lymphocytic leukemia. It shares structural similarities with and is a member of the IkappaB family of proteins. In this report, involvement of Bcl-3 in hematopoietic growth factor-stimulated erythroid proliferation and differentiation was examined. In TF-1 cells, an erythroleukemia cell line, granulocyte-macrophage colony-stimulating factor (GM-CSF) and erythropoietin (Epo) greatly enhanced Bcl-3 expression at both the protein and mRNA levels in association with stimulation of proliferation. Bcl-3 protein was also highly expressed in early burst-forming unit-erythroid (BFU-E)-derived erythroid precursors (day 7) and decreased during maturation (days 10 and 14), suggesting that Bcl-3 is involved in normal erythroid proliferation. In these hematopoietic cells, Bcl-3 was hyperphosphorylated. GM-CSF and Epo modulated the subcellular localization of Bcl-3. Upon stimulation of TF-1 cells with GM-CSF or Epo, the nuclear translocation of Bcl-3 was dramatically enhanced. Overexpression of Bcl-3 in TF-1 cells by transient transfection along with the NF-kappaB factors p50 or p52 resulted in significant induction of an human immunodeficiency virus-type 1 (HIV-1) kappaB-TATA-luceriferase reporter plasmid, demonstrating that Bcl-3 has a positive role in transactivation of kappaB-containing genes in erythroid cells. Stimulation with GM-CSF enhanced c-myb mRNA expression in these cells. Bcl-3 in nuclear extracts of TF-1 cells bound to a kappaB enhancer in the c-myb promoter together with NF-kappaB2/p52 and this binding activity was enhanced by GM-CSF stimulation. Furthermore, cotransfection of Bcl-3 with p52 or p50 in TF-1 cells resulted in significant activation of a c-myb kappaB-TATA-luceriferase reporter plasmid. These findings suggest that Bcl-3 may participate in the transcriptional regulation of certain kappaB-containing genes involved in hematopoiesis, including c-myb.

NF-kappaB transcription factors are involved in normal erythropoiesis

NF-kappaB/Rel designates a widely distributed family of transcription factors involved in immune and acute phase responses. Here, the expression and function of NF-kappaB factors in erythroid proliferation and differentiation were explored. In an erythroleukemia cell line, TF-1, high levels of p105/p50, p100/p52, p65, and IkappaBalpha were detected 24 hours after growth factor deprivation. In response to granulocyte-macrophage colony-stimulating factor (GM-CSF) stimulation, significant induction of p52 expression was observed. GM-CSF also induced nuclear translocation of both p52 and p65. No induction of NF-kappaB factors was observed with erythropoietin stimulation of TF-1 cells. Overexpression of p52 and p65 in TF-1 cells by transient transfection resulted in significant induction of a kappaB-TATA-luciferase reporter plasmid, showing that these factors are functional in vivo in erythroid cells. To determine whether NF-kappaB factors may play a role in normal erythropoiesis, levels of these factors were determined in burst-forming unit-erythroid (BFU-E)-derived cells at different stages of differentiation. The NF-kappaB factors p105/p50, p100/p52, and p65 were highly expressed in early BFU-E-derived precursors, which are rapidly proliferating, and declined during maturation. Furthermore, nuclear levels of NF-kappaB factors p50, p52, and p65 were higher in less mature precursors (day 10 BFU-E-derived cells) compared with more differentiated (day 14) erythroblasts. In nuclear extracts from day 10 BFU-E-derived cells, p50, p52, and p65 were able to form complexes, which bound to kappaB sites in the promoters of both the c-myb and c-myc genes, suggesting that c-myb and c-myc may be among the kappaB-containing genes regulated by NF-kappaB factors in normal erythroid cells. Taken together, these data show that NF-kappaB factors are modulated by GM-CSF and suggest they function to regulate specific kappaB containing genes involved in erythropoiesis.

Boyer's model of scholarship applied to a career ladder for nontenured nursing faculty

This article presents a career ladder for the reappointment and promotion of nontenured clinical faculty, based on Boyer's model of the scholarship of teaching, application, discovery, and integration and on his four principles and six standards. Titles, lengths of appointments, criteria, obligations, and professional development are defined for four levels of clinical faculty. Guide questions modeled on Boyer's dimensions of scholarship, principles, and standards that were used to guide the development of the career ladder are included.

Increased incidence of cancer in infants in the U.S.: 1980-1990

BACKGROUND

During the decade between 1980-1990, the rate of cancer in children in the U.S. increased. It is unknown whether cancer in infancy, which is biologically and clinically different from cancer in older children, also increased.

METHODS

To evaluate changes in cancer incidence in infants in the U.S. age < 1 year, data from the Surveillance, Epidemiology, and End Results (SEER) program and the U.S. Bureau of the Census were used to construct age specific, population-based cancer incidence rates.

RESULTS

Overall, the annual cancer rate in infants increased from 189 cases per million infants between 1979-1981 to 220 between 1989-1991. At both timepoints, female infants had higher cancer rates than male infants. Although the rates for female infants remained stable at 223 between 1979-1981 versus 236 between 1989-1991, rates for male infants increased from 158 to 205 during the same timepoints. Male infants had increased rates of central nervous system (CNS) tumors (P < 0.05), neuroblastoma, and retinoblastoma; female infants had increased rates of teratomas (P < 0.01) and hepatoblastomas. Between 1979-1981, the three most common types of cancer in infants were neuroblastoma, leukemia, and renal tumors (27%, 15%, and 14%, respectively), and were neuroblastoma, CNS tumors, and leukemia between 1989-1991 (27%, 15%, and 13%, respectively).

CONCLUSIONS

This study shows that the rate of certain types of cancer in infants in the U.S. is increasing. Studies of both genetic and environmental factors are needed to explain these increased rates and the changing distribution of cancer in the first year of life.

Use of competing conceptions of risk in animal agriculture

This study considers a theory of risk as a means of coping with risk and uncertainty that have become a growing reality for animal agriculture. Microbial contaminations of food, waste management, animal products in the human diet, and transmissible spongiform encephalopathies (TSE) incorporate different conceptions of risk and require different approaches to handling the uncertainty involved. A dichotomous schema is suggested to assist understanding risk that may be adapted to recognizing and handling risk. The polar aspects of the proposal are the probabilistic approach at one end and the contextual understanding at the other. Probabilist conceptions of risk presume that risk is determined by probability and consequence. Contextual conceptions presume that management, law, regulation, media, and public perceptions, as well as the severity of the consequence, will figure prominently in decision making in the face of uncertainty. Relative emphasis on probabilistic characteristics shapes distinct understandings of risk that can be plotted between the poles. We are proposing that these conceptualizations need not be issues only for debate but also for recognition of the probabilistic or contextual nature of the risk. Specific actions and policy may be constructed on the basis of the conceptualization. The bovine spongiform encephalopathy/new variant Creutzfeldt-Jakob disease complex is examined philosophically and methodologically as a contextual challenge to animal agriculture and associated industries. As such, the TSE serve as a case study of effective application of risk theory to risks in animal agriculture.

Relationships between experiences of parental violence during childhood and women's self-esteem

The interrelationships between experience of parental verbal aggression and physical violence during childhood and the development of low self-esteem during adulthood were explored separately for the father-daughter and mother-daughter relationships. Data were collected from 472 women between the ages of 18 and 45 during in-depth interviews drawn from five sources: outpatient alcoholism treatment, DWI (Driving While Intoxicated) education programs, shelter for battered women, outpatient mental health treatment, and randomly from the community. Control variables included respondents' alcohol problems and help-seeking behavior, parental alcohol problems, number of changes in childhood family (e.g., divorce), and respondents' race and social class. Controlling for these variables, experiences of father-to-daughter verbal aggression, moderate violence, and severe violence were found related to lower self-esteem in adulthood for women. Conversely, controlling for these variables, experiences of mother-to-daughter verbal aggression, moderate violence, and severe violence were not found related to lower self-esteem in adulthood for women.

Outbreaks of influenza A and B in a highly immunized nursing home population

BACKGROUND

Large outbreaks of influenza A and B may occur in nursing homes despite high resident vaccination rates, even when the vaccine strain is matched to the circulating strain. This study reports the occurrence of separate influenza A and B outbreaks in a nursing home where more than 85% of residents were vaccinated.

METHODS

Prospective surveillance was used to identify symptomatic residents in a rural Wisconsin nursing home with 680 residents. Viral cultures were obtained from all consenting residents identified with new respiratory symptoms even in the absence of temperature elevation. A "case" refers to a resident with a respiratory illness and an influenza isolate.

RESULTS

During the 1992-93 season, 86% of 670 total residents were vaccinated, 104 (15.5%) were cases with influenza B. During the 1993-94 season, 89% of 690 total residents were vaccinated, 68 (9.8%) were cases with influenza A. The antigenic matches between vaccine and epidemic strains were characterized as "identical or minimal difference" by the Centers for Disease Control and Prevention.

CONCLUSIONS

There is still a need to protect residents from infectious secretions and for contingency plans to permit the rapid use of antiviral agents. Future efforts are needed to develop vaccines that provide greater protection and to improve staff vaccination rates.

Expression of SCL is normal in transfusion-dependent Diamond-Blackfan anemia but other bHLH proteins are deficient

Basic helix-loop-helix proteins, which are tissue specific (SCL) or broadly expressed (E proteins), interact positively to regulate erythroid specific genes. Here, expression of SCL and two broadly expressed E proteins, E47 and HEB, was high early in erythroid differentiation and declined during maturation. Stimulation of erythroid progenitors/precursors with stem cell factor (SCF) enhanced SCL and E protein levels, one mechanism by which SCF may increase erythroid proliferation. Interactions between SCL and E proteins are competed by Id2, which binds and sequesters E proteins. Upregulation of Id2, demonstrated here late in erythroid differentiation, may downregulate genes involved in erythroid proliferation/differentiation. We examined expression of bHLH proteins in transfusion-dependent patients with Diamond-Blackfan anemia (DBA) to determine if these interactions are disrupted. In erythroblasts from patients, expression of SCL protein and mRNA was normal and SCL increased in response to SCF. However, E47 and HEB protein levels were significantly decreased. Id2 was strongly expressed in patients. Through reduction of SCL/E protein heterodimer formation, abnormal levels of bHLH transcription factors may affect expression of erythroid specific genes, such as beta globin. Stimulation of Diamond-Blackfan cells with SCF partially compensated for this defect, enhancing expression of E47, HEB, and SCL. SCF may function to increase SCL/E protein heterodimer formation, which may be one of the mechanisms through which SCF stimulates erythroid proliferation/differentiation in DBA.

Breast cancer clusters in the northeast United States: a geographic analysis

High breast cancer mortality rates have been reported in the northeastern part of the United States, with recent attention focused on Long Island, New York. In this study, the authors investigate whether the high breast cancer mortality is evenly spread over the Northeast, in the sense that any observed clusters of deaths can be explained by chance alone, or whether there are clusters of statistical significance. Demographic data and age-specific breast cancer mortality rates for women were obtained for all 244 counties in 11 northeastern states and for the District of Columbia for 1988-1992. A recently developed spatial scan statistic is used, which searches for clusters of cases without specifying their size or location ahead of time, and which tests for their statistical significance while adjusting for the multiple testing inherent in such a procedure. The basic analysis is adjusted for age, with further analyses examining how the results are affected by incorporating race, urbanicity, and parity as confounding variables. There is a statistically significant and geographically broad cluster of breast cancer deaths in the New York City-Philadelphia, Pennsylvania, metropolitan area (p = 0.0001), which has a 7.4% higher mortality rate than the rest of the Northeast. The cluster remains significant when race, urbanicity, and/or parity are included as confounding variables. Four smaller subclusters within this area are also significant on their own strength: Philadelphia with suburbs (p = 0.0001), Long Island (p = 0.0001), central New Jersey (p = 0.0001), and northeastern New Jersey (p = 0.0001). The elevated breast cancer mortality on Long Island might be viewed less as a unique local phenomenon and more as part of a more general situation involving large parts of the New York City-Philadelphia metropolitan area. The several known and hypothesized risk factors for which we could not adjust and that may explain the detected cluster are most notably age at first birth, age at menarche, age at menopause, breastfeeding, genetic mutations, and environmental factors.

Human papillomavirus type 16 DNA in esophageal carcinomas from Alaska Natives

The possible etiological role of human papillomavirus (HPV) in esophageal carcinogenesis was evaluated in Alaska Natives in whom the incidence of esophageal cancer is 1.3 and 3.8 times higher than in US Caucasian men and women, respectively. Fixed paraffin-embedded esophageal tissues from 32 cases of squamous-cell carcinoma (SCC) and 3 cases of adenocarcinoma (AC) diagnosed between 1957 and 1988 were analyzed by polymerase chain reaction (PCR) and in situ hybridization for HPV DNA sequences. Detection of the human beta-globin gene by PCR was used as a control for sufficiency of DNA and its potential for amplification in the tissue samples. Twenty-five of the tumor tissues were considered adequate for PCR analyses; HPV DNA was detected in 10 of 22 SCCs and was not found in 3 ACs. Seven of the 10 HPV-positive tissues contained sequences from the E6 gene of HPV type 16. Koilocytosis, an epithelial change consistent with HPV infection, was found in 80% of the esophageal squamous-cell tumors with HPV DNA and in 75% of those without HPV DNA. The detection of amplifiable cellular DNA was related to recentness of diagnosis; however, the detection of HPV DNA within amplifiable specimens was not related to recentness of diagnosis. A 413-bp sequence from the L1 open reading frame of HPV 16 from esophageal tissue of 2 patients was identical to sequences previously identified in cervical cells from other Alaska Natives. Our results provide molecular evidence of HPV infection, especially type 16, in archival esophageal cancer tissues from 45% of those patients whose specimens contain adequate DNA for PCR analysis.

Human papillomavirus types 52 and 58 are prevalent in cervical cancers from Chinese women

A substantial body of evidence has confirmed human papillomavirus (HPV) infection as an etiologic agent in human cervical cancer. To evaluate the association between HPV and cervical cancer in Chinese women, we examined tumor specimens from women who lived in Shanghai, People's Republic of China. Biopsies from 40 women, diagnosed with either squamous-cell carcinoma (n = 35) or adenocarcinoma (n = 5) were tested for HPV DNA by PCR. The HPV types present in tumors were determined either by hybridization of PCR products with HPV type-specific probes or by PCR-based sequencing. A total of 35 of the 40 cervical cancer specimens (87.5%) contained HPV DNA. The following distribution and types were detected: 7.5% HPV 16, 10% HPV 18, 20% HPVs 16 and 18, 15% HPV 52, 15% HPV 58, 12.5% HPVs 52 and 58 and 7.5% unclassified HPVs. In this population of Chinese women with cervical cancer, HPV 52 and 58 were as prevalent as the "high-risk" (for cervical cancer) viruses HPVs 16 and 18.

Alcohol feeding impedes early atherosclerosis in low-density lipoprotein receptor knockout mice: factors in addition to high-density lipoprotein-apolipoprotein A1 are involved

The effect of alcohol feeding on the development of atherosclerosis was investigated in low-density lipoprotein receptor gene-knockout (LDLR-/-) mice. Eight-week-old male mice were pair-fed atherogenic liquid diets containing ethanol at different levels (w/v; group A, 5%; group B, 2.5%; and group C, 0%). Tissue sections of the heart were stained with Oil Red O to examine for fatty lesions in proximal aorta. Results showed that the lesion size of group A was 70% smaller than group C after 6 weeks. By contrast, the lesion size of group B was not significantly different from that of group C. Serum high-density lipoprotein-apolipoprotein A1 (apo A1) A1 in LDLR-/- mice was suppressed by feeding the atherogenic diet, but the decrease was negated by alcohol (both groups A and B). The effectiveness of 5% alcohol to protect against atherosclerosis waned with time, but was still noticeable at 12 weeks, even though serum apo A1 remained high. Serum apolipoprotein E was increased by the high fat diet, but not altered by alcohol in the diet. Our data, therefore, show that: (1) alcohol-feeding impedes early atherosclerosis in LDLR-/- mice (this effect of alcohol is dose-dependent); (2) the protective effect of alcohol is not entirely attributable to an elevated serum high-density lipoprotein-apo A1; and (3) severe impairment of lipoprotein metabolism due to a lack of low-density lipoprotein receptors can eventually overwhelm the protective effect of alcohol against atherosclerosis.

Modulation of calcium channels in human erythroblasts by erythropoietin

Erythropoietin (Epo) induces a dose-dependent increase in intracellular free Ca2+ ([Ca2+]i) in human erythroblasts, which is dependent on extracellular Ca2+ and blocked by high doses of nifedipine or Ni2+. In addition, pretreatment of human erythroblasts with mouse antihuman erythropoietin receptor antibody but not mouse immunopure IgG blocked the Epo-induced [Ca2+]i increase, indicating the specificity of the Ca2+ response to Epo stimulation. In this study, the erythropoietin-regulated calcium channel was identified by single channel recordings. Use of conventional whole cell patch-clamp failed to detect Epo-induced whole cell Ca2+ current. To minimize washout of cytosolic constituents, we next used nystatin perforated patch, but did not find any Epo-induced whole cell Ca2+ current. Using Ba2+ (30 mmol/L) as charge carrier in cell-attached patches, we detected single channels with unitary conductance of 3.2 pS, reversal potential of +72 mV, and whose unitary current (at +10 mV) increased monotonically with increasing Ba2+ concentrations. Channel open probability did not appreciably change over the voltage range (-50 to +30 mV) tested. Epo (2 U/mL) increased both mean open time (from 4.27 +/- 0.75 to 11.15 +/- 1.80 ms) and open probability (from 0.26 +/- 0.06 to 2.56 +/- 0.59%) of this Ba(2+)-permeable channel. Our data strongly support the conclusion that the Epo-induced [Ca2+]i increase in human erythroblasts is mediated via Ca2+ entry through a voltage-independent Ca2+ channel.

Alcohol, drugs, and violence in children's lives

This chapter reviews the current state of knowledge concerning the interrelationship between the cycle of alcohol and other drugs (AOD) use and the cycle of violence. This issue is framed in terms of two questions. The first is the extent to which AOD use by the perpetrator is related to the perpetration of violence toward children, defined here as including both physical and sexual abuse. The second question is whether the experience of abuse during childhood is related to the subsequent development of the abuse of alcohol and other drugs. The review indicates that parental AOD abuse is related to physical and sexual abuse. However, because most perpetrators are not parents, the relationship is not yet clear. The data do support the link between experiencing childhood violence and the development of later AOD abuse. Theoretical explanations for each link are reviewed and mediating variables are identified. The review concludes with a presentation of methodological issues and the directions for future research.

Recent trends in U.S. breast cancer incidence, survival, and mortality rates

BACKGROUND

Clinical trials have demonstrated that use of mammographic screening and advances in therapy can improve prognosis for women with breast cancer.

PURPOSE

We determined the trends in breast cancer mortality rates, as well as incidence and survival rates by extent of disease at diagnosis, for white women in the United States and considered whether these trends are consistent with widespread use of such beneficial medical interventions.

METHODS

We examined mortality data from the National Center for Health Statistics and incidence and survival data by extent of disease from the Surveillance, Epidemiology, and End Results Program of the National Cancer Institute, all stratified by patient age, using statistical-regression techniques to determine changes in the slope of trends over time.

RESULTS

The age-adjusted breast cancer mortality rate for U.S. white females dropped 6.8% from 1989 through 1993. A significant decrease in the slope of the mortality trend of approximately 2% per year was observed in every decade of age from 40 to 79 years of age. Trends in incidence rates were also similar among these age groups: localized disease rates increased rapidly from 1982 through 1987 and stabilized or increased more slowly thereafter; regional disease rates decreased after 1987; and distant disease rates have remained level over the past 20 years. Three-year relative survival rates increased steadily and significantly for both localized and regional disease from 1980 through 1989 in all ages, with no evidence of an increase in slope in the late 1980s.

IMPLICATIONS

The decrease in the diagnosis of regional disease in the late 1980s in women over the age of 40 years likely reflects the increased use of mammography earlier in the 1980s. The increase in survival rates, particularly for regional disease, likely reflects improvements in systemic adjuvant therapy. Statistical modeling indicates that the recent drop in breast cancer mortality is too rapid to be explained only by the increased use of mammography; likewise, there has been no equivalent dramatic increase in survival rates that would implicate therapy alone. Thus, indications are that both are involved in the recent rapid decline in breast cancer mortality rates in the United States.

G-protein alpha subunit Gi(alpha)2 mediates erythropoietin signal transduction in human erythroid precursors

Erythropoietin induces a dose-dependent increase in cytosolic calcium in human erythroblasts that is mediated by a voltage-independent Ca2+ channel. Inhibition of this response to erythropoietin by pertussis toxin suggests involvement of guanine nucleotide-binding regulatory proteins (G-proteins). The role of G-proteins in regulation of the erythropoietin-modulated Ca2+ channel was delineated here by microinjection of G-protein modulators or subunits into human erythroid precursors. This is the first report on the use of microinjection to study erythropoietin signal transduction in normal precursor cells. Fura-2 loaded day-10 burst-forming units-erythroid-derived erythroblasts were used for microinjection and free intracellular calcium concentration ([Ca(i)]) was measured with digital video imaging. BCECF (1,2',7'-bis(2-carboxyethyl)-5-(and -6-)-carboxyfluorescein) was included in microinjectate, and an increase in BCECF fluorescence was evidence of successful microinjection. Cells were microinjected with nonhydrolyzable analogues of GTP, GTPgammaS or GDPbetaS, which maintain the alpha subunit in an activated or inactivated state, respectively. [Ca(i)] increased significantly in a dose-dependent manner after microinjection of GTPgammaS. However, injection of GDPbetaS blocked the erythropoietin-induced calcium increase, providing direct evidence that activation of a G-protein is required. To delineate which G-protein subunits are involved, alpha or betagamma transducin subunits were purified and microinjected as a sink for betagamma or alpha subunits in the erythroblast, respectively. Transducin betagamma, but not alpha, subunits eliminated the calcium response to erythropoietin, demonstrating the primary role of the alpha subunit. Microinjected antibodies to Gi(alpha)2, but not Gi(alpha)1 or Gi(alpha)3, blocked the erythropoietin-stimulated [Ca(i)] rise, identifying Gi(alpha)2 as the subunit involved. This was confirmed by the ability of microinjected recombinant myristoylated Gi(alpha)2, but not Gi(alpha)1 or Gi(alpha)3 subunits, to reconstitute the response of pertussis toxin-treated erythroblasts to erythropoietin. These data directly demonstrate a physiologic function of G-proteins in hematopoietic cells and show that Gi(alpha)2 is required in erythropoietin modulation of [Ca(i)] via influx through calcium channels.

Glutamate-mediated slow synaptic currents in neonatal rat deep dorsal horn neurons in vitro

1. The role of glutamate in slow excitatory synaptic transmission between small-diameter primary afferents and deep dorsal horn neurons was examined in neonatal rat spinal cord in vitro with the use of the whole cell voltage-clamp technique. 2. Single-shock electrical stimulation of large-diameter A beta-fibers evoked a short-latency (< 10 ms) fast (< 500 ms) excitatory postsynaptic current (EPSC). Stimulation of small-diameter A delta- and C fibers resulted, in addition, in a slowly rising and decaying EPSC (lasting up to 14 s) following the fast EPSC. The slow EPSC was never observed with stimulation of A beta-fibers. 3. Two patterns of EPSCs were observed, "type 1" and "type 2," which differed in their time course (lasting up to 1 and 14 s, respectively). The type 1 response was biphasic, with a fast monosynaptic component followed by an invariant, presumably monosynaptic, late slow component. The type 2 response was multiphasic, with a fast monosynaptic component followed by a slow component composed of fast polysynaptic currents superimposed on a slow current. 4. The fast monosynaptic component had a linear conductance, whereas the late slower component of the A beta-fiber-evoked response had a negative slope conductance at holding potentials more negative than -23 mV. Both currents reversed at a membrane potential of -1.2 +/- 2.8 (SE) mV. 5. With the use of selective non-N-methyl-D-aspartate (non-NMDA) and NMDA receptor antagonists [6-cyano-7-nitroquinox-aline-2,3-dione (CNQX) or 2,3-dihydroxy-6-nitro-7-sulphamoyl-benzo (F) quinoxaline and D(-)-2-amino-5-phosphonopentanoic acid (D-AP5), respectively] we showed that both the early fast (A beta-fiber evoked) and the late slow (A delta- and C fiber evoked) components were mediated by non-NMDA and NMDA receptors. CNQX suppressed both the early fast and late slow components of the compound EPSC, whereas D-AP5 suppressed the polysynaptic currents of the early fast component and the late slow component without significantly affecting the early fast monosynaptic component. 6. Slow EPSCs summated on low-frequency (1 or 10 Hz), repetitive stimulation and produced long-duration "tail" currents on cessation of the stimulus. The amount of temporal summation was proportional to the duration of the slow EPSC and the frequency of stimulation. 7. Our results suggest that slow ionotropic-glutamate-receptor-mediated EPSCs produced by the stimulation of small-diameter primary afferents play an important role in activity-dependent synaptic plasticity in the dorsal horn.

Potassium channels of adult locust (Schistocerca gregaria) muscle

Two types of K+ channels have been identified in patches of plasma membrane of metathoracic extensor tibiae muscle fibres of adult locust, Schistocerca gregaria. One channel had a maximum conductance of 170 pS, fast open-closed kinetics, and a linear current/ voltage relationship. In inside-out patches it was activated by "internally applied" Ca2+, but at unexpectedly low levels (between 10(-10) and 10(-9)M). The other channel had a maximum conductance of 35 pS, slower open-closed kinetics, and was not activated by Ca2+. In cell-attached patches, its channel conductance measured in symmetrical salines was about three times greater for hyperpolarisations than for depolarisations. This inward rectification was proved to be due to block by intracellular Mg2+. For both channels, open probability (Po) and mean open time increased during depolarisations and decreased during hyperpolarisations, resulting in outward rectifications in terms of net current (I n, product of the single-channel current and Po). For both channels, the K+ conductance was 10 times greater than that for Na+. Internally applied tetraethylammonium or tetramethylammonium ions blocked both channels.

Report of an outbreak: nursing home architecture and influenza-A attack rates

OBJECTIVE

To determine factors that might account for a significantly lower attack rate in a newly constructed nursing building during an epidemic of type A influenza.

SETTING

A four-building, long-term care facility for veterans and their spouses, with an average daily census of 690.

DESIGN

Prospective surveillance with retrospective analysis.

PARTICIPANTS

Symptomatic residents submitting to viral culture.

MEASUREMENTS

Number of respiratory illnesses and influenza cultures in consenting symptomatic residents. Building characteristics.

RESULTS

An influenza A (H3N2) outbreak was culture-confirmed in 68 nursing home residents. Influenza A was isolated in 3/184 (2%) residents in Building A, 31/196 (16%) in Building B, 18/194 (9%) in Building C, and 16/116 (14%) in Building D. Denominators are average daily census during the outbreak. Building A had significantly fewer culture-confirmed cases than the other buildings (P < .001). Fewer residents in Building A, 47% compared with 61% in Buildings B, C, and D, were participants in a formal study of influenza. Eight of 15 respiratory illnesses identified during the outbreak that were not cultured occurred in Building A. These factors could not account for the difference in attack rates. Building A has a unique ventilation system, more square feet of public space per resident, and does not contain office space that serves the entire four-building facility.

CONCLUSION

Our retrospective observation suggests that architectural design may influence the attack rate of influenza A in nursing homes.

Assessing alcohol problems in female DWI offenders

The severity of alcohol problems in a sample of 812 women driving while intoxicated (DWI) offenders enrolled in a Drinking Driver Program in New York State was assessed through the use of multiple measures. These women voluntarily provided information through a self-administered questionnaire completed at the beginning of the program. Classification of alcohol problems based on DSM-III-R criteria was compared with classification based on the use of alcohol-specific and nonalcohol-specific measures of alcohol-related problems. Greater hostility and a larger number of drinks ever consumed accounted for nearly 12% of the variance between no diagnosis and alcohol abuse women, whereas these two variables plus age, race, depression, and having a relative with alcohol problems accounted for nearly 41% of the variance between alcohol abuse and dependent women. A subsample of women within each DSM-III-R diagnostic group showed high risk for later, more severe alcohol problems. Multiple measures of alcohol problems help to elucidate subtle differences in alcohol problems within each of the broad categories specified by the DSM, and should facilitate more appropriate intervention and treatment plans for women DWI offenders with alcohol-related problems.

The impact of stage and histology on the long-term clinical course of 163,808 patients with breast carcinoma

BACKGROUND

Stage and histologic type have a significant impact on the long term clinical course of breast carcinoma. Clinical course is governed by two components: likelihood of cure and medial tumor-related survival time among uncured patients. Estimates of these components can be derived only by using survival models that incorporate cured fraction as a specific parameter.

METHODS

The prognostic value of stage and histologic type was determined for 163,808 patients with breast carcinoma using the log normal and log logit cure-based survival models. Follow-up ranged from 1 month to 19 years and was obtained from the SEER Program.

RESULTS

In approximate terms, ductal carcinoma was diagnosed in 70% of the patients, with estimate cured fractions of 2/3 and 1/3 for local and regional disease, respectively. Estimates of medial survival times for uncured patients were 10 and 5 years. Findings were similar for patients with tumor of miscellaneous histologic types. For patients with medullary carcinoma were 82% and 50%, with median survival times of 6 and 4 years. For patients with mucinous, lobular, and ductolobular carcinomas, parametric analysis gave inconsistent estimates of cured fraction, but findings suggested unusually long tumor-related survival times.

CONCLUSIONS

Cured-based parametric survival models offer valuable insight into the impact of stage and histology on the clinical course of breast cancer.

Validation of an inclusive model of sexual minority identity formation on a sample of gay men

This article outlines the preliminary validation of a new, inclusive model of sexual minority identity formation (McCarn & Fassinger, 1996) on a sample of gay men. The model hypothesizes two separate but reciprocal processes of individual sexual identity development and group membership identity development in a four-phase developmental sequence. The model was developed and successfully validated on a sample of lesbians (briefly described here), and the present study replicates and extends this work, using a modified Q-sort methodology, on a sample of 34 diverse gay men. Results indicated support for the model, in terms of both individual and group processes as well as phases, and suggested that the model is applicable to gay men. Implications of the study for theory, research, and practice are discussed.