Modulation of fear behavior and neuroimmune alterations in house dust mite exposed A/J mice, a model of severe asthma.

Fear-associated conditions such as posttraumatic stress disorder (PTSD) and panic disorder (PD) are highly prevalent. There is considerable interest in understanding contributory risk and vulnerability factors. Accumulating evidence suggests that chronically elevated inflammatory load may be a potential risk factor for these disorders. In this regard, an association of asthma, a chronic inflammatory condition, with PTSD and PD has been reported. Symptoms of PD and PTSD are more prevalent in severe asthmatics, compared to those with mild or moderate asthma suggesting that factors that influence the severity of asthma, may also influence susceptibility to the development of fear-related disorders. There has been relatively little progress in identifying contributory factors and underlying mechanisms, particularly, the translation of severe asthma-associated lung inflammation to central neuroimmune alterations and behavioral manifestations remains unclear. The current study investigated the expression of behaviors relevant to PD and PTSD (CO2 inhalation and fear conditioning/extinction) in A/J mice using a model of severe allergic asthma associated with a mixed T helper 2 (Th2) and Th17 immune response. We also investigated the accumulation of Th2- and Th17-cytokine expressing cells in lung and brain tissue, microglial alterations, as well as neuronal activation marker, delta FosB (ΔFosB)) in fear and panic regulatory brain areas. HDM-exposed mice elicited higher freezing during fear extinction. CO2-associated spontaneous and conditioned freezing, as well as anxiety or depression-relevant exploratory and coping behaviors were not altered by HDM treatment. A significant increase in brain Th17-associated inflammatory mediators was observed prior to behavioral testing, accompanied by microglial alterations in specialized blood brain barrier-compromised circumventricular area, subfornical organ. Post extinction measurements revealed increased ΔFosB staining within the medial prefrontal cortex and basolateral amygdala in HDM-treated mice. Collectively, our data show modulation of brain immune mechanisms and fear circuits by peripheral airway inflammation, and is relevant to understanding the risk and comorbidity of asthma with fear-associated disorders such as PTSD.

Rapid adaptive evolution in novel environments acts as an architect of population range expansion.

Colonization and expansion into novel landscapes determine the distribution and abundance of species in our rapidly changing ecosystems worldwide. Colonization events are crucibles for rapid evolution, but it is not known whether evolutionary changes arise mainly after successful colonization has occurred, or if evolution plays an immediate role, governing the growth and expansion speed of colonizing populations. There is evidence that spatial evolutionary processes can speed range expansion within a few generations because dispersal tendencies may evolve upwards at range edges. Additionally, rapid adaptation to a novel environment can increase population growth rates, which also promotes spread. However, the role of adaptive evolution and the relative contributions of spatial evolution and adaptation to expansion are unclear. Using a model system, red flour beetles (Tribolium castaneum), we either allowed or constrained evolution of populations colonizing a novel environment and measured population growth and spread. At the end of the experiment we assessed the fitness and dispersal tendency of individuals originating either from the core or edge of evolving populations or from nonevolving populations in a common garden. Within six generations, evolving populations grew three times larger and spread 46% faster than populations in which evolution was constrained. Increased size and expansion speed were strongly driven by adaptation, whereas spatial evolutionary processes acting on edge subpopulations contributed less. This experimental evidence demonstrates that rapid evolution drives both population growth and expansion speed and is thus crucial to consider for managing biological invasions and successfully introducing or reintroducing species for management and conservation.

Altered Fear Behavior in Aeroallergen House Dust Mite Exposed C57Bl/6 Mice: A Model of Th2-skewed Airway Inflammation.

There is a growing interest for studying the impact of chronic inflammation, particularly lung inflammation, on the brain and behavior. This includes asthma, a chronic inflammatory condition, that has been associated with psychiatric conditions such as posttraumatic stress disorder (PTSD). Although asthma is driven by elevated production of Th2 cytokines (IL-4, IL-5 and IL-13), which drive asthma symptomology, recent work demonstrates that concomitant Th1 or Th17 cytokine production can worsen asthma severity. We previously demonstrated a detrimental link between PTSD-relevant fear behavior and allergen-induced lung inflammation associated with a mixed Th2/Th17-inflammatory profile in mice. However, the behavioral effects of Th2-skewed airway inflammation, typical to mild/moderate asthma, are unknown. Therefore, we investigated fear conditioning/extinction in allergen house dust mite (HDM)-exposed C57Bl/6 mice, a model of Th2-skewed allergic asthma. Behaviors relevant to panic, anxiety, and depression were also assessed. Furthermore, we investigated the accumulation of Th2/Th17-cytokine-expressing cells in lung and brain, and the neuronal activation marker, ΔFosB, in fear regulatory brain areas. HDM-exposed mice elicited lower freezing during fear extinction with no effects on acquisition and conditioned fear. No HDM effect on panic, anxiety or depression-relevant behaviors was observed. While HDM evoked a Th2-skewed immune response in lung tissue, no significant alterations in brain Th cell subsets were observed. Significantly reduced ΔFosB+ cells in the basolateral amygdala of HDM mice were observed post extinction. Our data indicate that allergen-driven Th2-skewed responses may induce fear extinction promoting effects, highlighting beneficial interactions of Th2-associated immune mediators with fear regulatory circuits.

A randomized clinical trial of anticaries therapies targeted according to risk assessment (caries management by risk assessment).

This randomized parallel group clinical trial assessed whether combined antibacterial and fluoride therapy benefits the balance between caries pathological and protective factors. Eligible, enrolled adults (n = 231), with 1-7 baseline cavitated teeth, attending a dental school clinic were randomly assigned to a control or intervention group. Salivary mutans streptococci (MS), lactobacilli (LB), fluoride (F) level, and resulting caries risk status (low or high) assays were determined at baseline and every 6 months. After baseline, all cavitated teeth were restored. An examiner masked to group conducted caries exams at baseline and 2 years after completing restorations. The intervention group used fluoride dentifrice (1,100 ppm F as NaF), 0.12% chlorhexidine gluconate rinse based upon bacterial challenge (MS and LB), and 0.05% NaF rinse based upon salivary F. For the primary outcome, mean caries increment, no statistically significant difference was observed (24% difference between control and intervention groups, p = 0.101). However, the supplemental adjusted zero-inflated Poisson caries increment (change in DMFS) model showed the intervention group had a statistically significantly 24% lower mean than the control group (p = 0.020). Overall, caries risk reduced significantly in intervention versus control over 2 years (baseline adjusted generalized linear mixed models odds ratio, aOR = 3.45; 95% CI: 1.67, 7.13). Change in MS bacterial challenge differed significantly between groups (aOR = 6.70; 95% CI: 2.96, 15.13) but not for LB or F. Targeted antibacterial and fluoride therapy based on salivary microbial and fluoride levels favorably altered the balance between pathological and protective caries risk factors.

Molecular cloning and disease association of hepatitis G virus: a transfusion-transmissible agent.

An RNA virus, designated hepatitis G virus (HGV), was identified from the plasma of a patient with chronic hepatitis. Extension from an immunoreactive complementary DNA clone yielded the entire genome (9392 nucleotides) encoding a polyprotein of 2873 amino acids. The virus is closely related to GB virus C (GBV-C) and distantly related to hepatitis C virus, GBV-A, and GBV-B. HGV was associated with acute and chronic hepatitis. Persistent viremia was detected for up to 9 years in patients with hepatitis. The virus is transfusion-transmissible. It has a global distribution and is present within the volunteer blood donor population in the United States.

Nonlinear stresses and temperatures in transient adiabatic and shear flows via nonequilibrium molecular dynamics: Three definitions of temperature.

We compare nonlinear stresses and temperatures for adiabatic-shear flows, using up to 262, 144 particles, with those from corresponding homogeneous and inhomogeneous flows. Two varieties of kinetic temperature tensors are compared to the configurational temperatures. This comparison of temperatures led us to two findings beyond our original goal of analyzing shear algorithms. First, we found an improved form for local instantaneous velocity fluctuations, as calculated with smooth-particle weighting functions. Second, we came upon the previously unrecognized contribution of rotation to the configurational temperature.

Cell cycle-regulated association of E2F1 and Sp1 is related to their functional interaction.

Because of the large number of growth-regulated genes containing binding sites for the transcription factors Sp1 and E2F and the reported ability of E2F to mediate cell cycle (growth) regulation, we studied interactions between E2F1 and Sp1. In transient transfection assays using Drosophila melanogaster SL2 cells, transfection with both Sp1 and E2F1 expression vectors resulted in greater than 85-fold activation of transcription from a hamster dihydrofolate reductase reporter construct, whereas cotransfection with either the Sp1 or E2F1 expression vector resulted in 30- or <2-fold activation, respectively. Therefore, these transcription factors act synergistically in activation of dihydrofolate reductase transcription. Transient transfection studies demonstrated that E2F1 could superactivate Sp1-dependent transcription in a promoter containing only Sp1 sites and that Sp1 could superactivate transcription of promoters through E2F sites, further demonstrating that these physically associated in Drosophila cells transfected with Sp1 and E2F1 expression vectors and in human cells, with maximal interaction detected in mid- to late G1. Additionally, E2F1 and Sp1 interact in vitro through specific domains of each protein, and the physical interaction and functional synergism appear to require the same regions. Taken together, these data demonstrate that E2F1 and Sp1 both functionally and physically interact; therefore this interaction, Sp1 and E2F1 may regulate transcription of genes containing binding sites for either or both factors.

Fluoride varnish efficacy in preventing early childhood caries.

To determine the efficacy of fluoride varnish (5% NaF, Duraphat, Colgate) added to caregiver counseling to prevent early childhood caries, we conducted a two-year randomized, dental-examiner-masked clinical trial. Initially, 376 caries-free children, from low-income Chinese or Hispanic San Francisco families, were enrolled (mean age +/- standard deviation, 1.8 +/- 0.6 yrs). All families received counseling, and children were randomized to the following groups: no fluoride varnish, fluoride varnish once/year, or fluoride varnish twice/year. An unexpected protocol deviation resulted in some children receiving less active fluoride varnish than assigned. Intent-to-treat analyses showed a fluoride varnish protective effect in caries incidence, p < 0.01. Analyzing the number of actual, active fluoride varnish applications received resulted in a dose-response effect, p < 0.01. Caries incidence was higher for 'counseling only' vs. 'counseling + fluoride varnish assigned once/year' (OR = 2.20, 95% CI 1.19-4.08) and 'twice/year' (OR = 3.77, 95% CI 1.88-7.58). No related adverse events were reported. Fluoride varnish added to caregiver counseling is efficacious in reducing early childhood caries incidence.

Inhibition of spleen cell cytotoxic capacity toward tumor by elevated prostaglandin E2 levels in mice bearing Lewis lung carcinoma.

The capacity to generate cytotoxic cells toward Lewis lung carcinoma (LLC) in mixed cultures of stimulator LLC and responder spleen cells of LLC-bearing C57BL/6 mice was monitored during the course of tumor growth. The cytotoxic response of mice bearing tumors that were not yet palpable was enhanced. However, as palpable tumors developed and tumor growth progressed, their cytotoxic capacity became suppressed. Concurrent with this decline in cytotoxic capacity, there was an increase in systemic immunoreactive prostaglandin E2 (PGE2) concentrations in tumor-bearing mice. Administration of indomethacin, a prostaglandin synthesis inhibitor, to LLC-bearing mice prevented the rise in PGE2 concentrations and the suppression in cytotoxic capacity toward LLC. A relationship between the elevated immunoreactive PGE2 levels, suppression in cytotoxic capacity, and progressive tumor growth was indicated when administration of indomethacin to tumor-bearing mice also reduced the rate of tumor development.

Characterization of oral streptococci that activate the dietary glycoside rutin to a mutagen.

Oral streptococci are described that hydrolyze the dietary glycoside rutin (CAS: 153-18-4), resulting in mutagenic activity. Bacteria that hydrolyze rutin were isolated from the mouth of each of 10 healthy volunteers. The activity was inducible, and the product was mutagenic in the Salmonella mutagenicity assay. These bacteria were present in the greatest proportion on the dorsum of the tongue where they formed 1.5% of the total cultivable microflora. The appearance of the colonies, cell morphology, and biochemical characteristics were those of Streptococcus milleri. However, rutin hydrolysis did not occur with any of 30 isolates of this species from blood of patients with bacteremia, with any of 4 stock strains, or with any of 14 strains of streptococci from the other 4 major oral species. Therefore, activation of rutin to a mutagen is not a universal function of the normal oral flora, but it can be accomplished by some strains of S. milleri.

Evidence of an agrin receptor in cortical neurons.

Agrin plays a key role in directing the differentiation of the vertebrate neuromuscular junction. Understanding agrin function at the neuromuscular junction has come via molecular genetic analyses of agrin as well as identification of its receptor and associated signal transduction pathways. Agrin is also expressed by many populations of neurons in brain, but its role remains unknown. Here we show, in cultured cortical neurons, that agrin induces expression of the immediate early gene c-fos in a concentration-dependent and saturable manner, as expected for a signal transduction pathway activated by a cell surface receptor. Agrin is active in cortical neurons at picomolar concentrations, is Ca(2+) dependent, and is inhibited by heparin and staurosporine. Despite marked differences in acetylcholine receptor (AChR)-clustering activity, all alternatively spliced forms of agrin are equally potent inducers of c-fos in cortical neurons. A similar, isoform-independent response to agrin was also observed in cultures prepared from the hippocampus and cerebellum. Only agrin with high AChR-clustering activity was effective in cultured muscle, whereas non-neuronal cells were agrin insensitive. Although consistent with a receptor tyrosine kinase model similar to the muscle-specific kinase-myotube-associated specificity component complex in muscle, our data suggest that CNS neurons express a unique agrin receptor. Evidence that neuronal signal transduction is mediated via an increase in intracellular Ca(2+) means that agrin is well situated to influence important Ca(2+)-dependent functions in brain, including neuronal growth, differentiation, and adaptive changes in gene expression associated with synaptic remodeling.

Repeat coronary angioplasty: efficacy of a third angioplasty for a second restenosis.

To determine the efficacy of repeat percutaneous transluminal coronary angioplasty, 74 patients were studied who underwent a third angioplasty for a second restenosis of one coronary artery segment. The procedure was successful in 93% of patients. Procedural complications included emergency bypass surgery (three patients) and in-hospital death (two patients). At late follow-up (mean 18 months, range 7 to 49), 30 patients (43%) had a third restenosis treated with either a fourth angioplasty (16 patients), coronary bypass surgery (11 patients) or medical management (1 patient). Thirty-nine patients (57%) had no restenosis on the basis of follow-up angiography or absence of symptoms previously attributed to restenosis. Factors associated with a third restenosis included a shorter time interval (less than 3 months) between previous angioplasty procedures and dilation of the left anterior descending coronary artery. Among the 16 patients undergoing a fourth angioplasty for a third restenosis, the procedural success rate was 94%. One patient required emergency bypass surgery. At late follow-up (mean 16 months, range 7 to 38), eight patients (53%) had a fourth restenosis treated with either a fifth angioplasty (one patient), bypass surgery (five patients) or medical management (two patients). Considering all 74 patients undergoing a third angioplasty for a second restenosis, 27% had bypass surgery, 5% died, 4% were managed medically and 64% were free of angina at late follow-up after either a third, fourth or fifth angioplasty. Restenosis rates after a third or fourth angioplasty procedure for recurrent restenosis are higher than those for the initial procedures.(ABSTRACT TRUNCATED AT 250 WORDS)

Marital conflict of manic-depressive patients.

Forty-two manic-depressive inpatients and their spouses, as well as 30 "normal" pairs from the community, reported on marital dissension through the Conflict in Marriage Scale (CIMS), an agree-disagree card sort. The marriages of manic-depressives were significantly higher in acknowledged conflict then those of community pairs, and the patients reported significantly more conflict then their spouses did. There was no correlation between levels of conflict reported by patients compared with their spouses though conflict levels of community pairs were significantly correlated with each other. This leads to the speculation that manic-depressive marriages may be characterized by more complementarity than similarity of partners.

Accuracy of perceiving blood glucose in IDDM.

Type I (insulin-dependent) diabetic individuals and health professionals often assume that the symptoms of extremely low or high blood glucose (BG) levels can be recognized and, consequently, appropriate treatment decisions can be based on symptom perception. Because no research has documented the validity of these assumptions, this study tested the ability to perceive BG concentration. Nineteen type I adults, experienced in self-monitoring of BG (SMBG), estimated their BG 40-54 times just before measurement of actual BG. This procedure was repeated under two conditions: (1) in the hospital (hospital condition) while connected to an insulin/glucose infusion system that artificially manipulated BG, leaving subjects only symptomatic, or internal, cues and (2) in the natural environment (home condition), where both internal and external cues, e.g., food and insulin consumption, were available. Estimates significantly correlated with actual BG for 7 of 16 subjects in the hospital condition and for 18 of 19 subjects in the home condition. Believed ability to estimate BG did not predict documented ability in either condition. An evaluation of the treatment significance of estimation errors showed that the majority of errors were relatively benign. The most common error affecting clinical outcome was estimated euglycemia when actual BG was hypoglycemic or hyperglycemic.

Effects of endothelial and inducible nitric oxide synthases inhibition on circulatory function in rats after myocardial infarction.

OBJECTIVES: To examine the relative roles of eNOS and iNOS (endothelial and inducible nitric oxide synthases) on basal and beta-adrenergic receptor (beta-AR)-stimulated arterial hemodynamic responses after myocardial infarction (MI). METHODS: Left ventricular (LV) pressures and steady-state and pulsatile arterial hemodynamics were measured at baseline, and after acute NOS inhibition with either NG-nitro-L-arginine methyl ester (L-NAME, 100 mg/kg) or iNOS inhibition with aminoguanidine (AG, 75 mg/kg) in sham-operated and MI Sprague-Dawley rats. RESULTS: In sham rats, L-NAME decreased (P < 0.05) peak positive LV dP/dt and aortic blood velocity by 19% and 53%, respectively, and increased (P < 0.05) mean arterial pressure (MAP); systemic vascular resistance, and LV end-diastolic pressure (EDP) by 20, 189 and 89%, respectively. The frequency-dependent components of hemodynamics including aortic input impedance modulus, characteristic impedance, and phase shift were increased (P < 0.05) with L-NAME, while pulsatile power was decreased (P < 0.05). AG increased (P < 0.05) aortic input impedance modulus and characteristic impedance but had no effect on any other hemodynamic variable. In MI rats, L-NAME decreased (P < 0.05) LV dP/dt and aortic blood velocity by 22 and 55%, respectively, and increased (P < 0.05) SVR by 108%. There was no effect of L-NAME on MAP or LV EDP in MI rats. After MI, AG increased (P < 0.05) heart rate and LV dP/dt but had no effect on other LV or pulsatile hemodynamic variables. Compared to sham rats, heart rate, LV dP/dt, and blood velocity-isoproterenol dose responses were shifted downward (P < 0.05), while SVR-isoproterenol dose response was shifted upward (P < 0.05) in MI rats. In sham rats, L-NAME potentiated (P < 0.05, at > 10(-2) micrograms/kg) the isoproterenol-induced increase in LV dP/dt and aortic blood velocity, and potentiated (P < 0.05) the isoproterenol-induced decline in SVR. As expected, AG had no effects on isoproterenol-stimulated hemodynamics in sham rats. After MI, there was no effect of L-NAME or AG on isoproterenol-stimulated hemodynamics. CONCLUSIONS: (1) Circulatory and cardiac responses to inhibition of NO by L-NAME suggest that eNOS, but not iNOS, is the principal regulator of integrated arterial hemodynamic function in rats. (2) Both basal and beta-AR-stimulated NO regulation of hemodynamic are attenuated after MI. (3) The attenuation of arterial hemodynamic effects after isoproterenol is mediated, in part, by alterations in the beta-AR-activation of eNOS system after MI.

Variation in ECT use in the United States.

OBJECTIVE: The authors measured the variation in ECT utilization rates across 317 metropolitan statistical areas of the United States and determined to what degree this variation is associated with health care system characteristics, demographic factors, and the stringency of state regulation of ECT. METHOD: Data from APA's 1988-1989 Professional Activities Survey were used to estimate ECT utilization rates for the metropolitan statistical areas. Multiple regression analysis was used to determine the relative influence of provider, demographic, and regulatory factors on variation in ECT use across areas. RESULTS: Among the psychiatrists surveyed, 17,729 reported treating 4,398 patients with ECT during the study period. No ECT use was reported in 115 metropolitan statistical areas. Among the remaining 202 metropolitan statistical areas, annual ECT use varied from 0.4 to 81.2 patients per 10,000 population. The strongest predictors of variation in ECT use across metropolitan statistical areas were the number of psychiatrists, number of primary care physicians, number of private hospital beds per capita, and stringency of state regulation of ECT. CONCLUSIONS: Rates of ECT use were highly variable, higher than for most medical and surgical procedures. In some urban areas, access to ECT appears limited. Predictors of variation in ECT rates have implications for expanding access to the procedure. The extent of variation suggests psychiatrists continue to lack consensus regarding the use of ECT. Better data on the effectiveness of psychiatric treatments may lead to a broader professional consensus and may narrow variations in clinical practices.

A national study of psychiatric hospital care.

BACKGROUND: The delivery system for psychiatric inpatient services in the United States has changed dramatically over the past 30 years, undergoing a marked privatization. METHOD: To assess the effect of changes in ownership and types of inpatient settings on the structure of the mental health services system, the authors surveyed a national sample of nonfederal mental health facilities in 1988. RESULTS: Comparing their data to those of earlier surveys, they found that a decline in the number of patients per staff occurred in most settings over the last decade, suggesting that this aspect of quality of care may have improved. They observed important ownership-related differences in 1988 in diagnostic mix (e.g., more schizophrenia treated in public facilities than in private ones) and in payer source (e.g., more third-party revenues in public facilities than occurred in the past). CONCLUSIONS: There was a significant interaction between ownership form and type of facility, suggesting that the type of inpatient setting, ownership, and the relation between the two should be considered in assessing the impact of privatization on the accessibility of health care available for the mentally ill. The authors found that the increase in private psychiatric hospitals has widened the availability and choice of treatment facilities for those with private funding sources (especially children and adolescents) but has not had a similar effect in increasing sources of care for the seriously mentally ill dependent upon public financing.

Characteristics of psychiatrists who perform ECT.

OBJECTIVE: Use of ECT is highly variable, and previous study has linked its availability to the geographic concentration of psychiatrists. However, less than 8% of all U.S. psychiatrists provide ECT. The authors analyzed the characteristics of psychiatrists who use ECT to understand more fully the variation in its use and how changes in the psychiatric workforce may affect its availability. METHOD: Data from the 1988-1989 Professional Activities Survey were examined to investigate the influence of demographic, training, clinical practice, and geographic characteristics on whether psychiatrists use ECT. RESULTS: Psychiatrists who provided ECT were more likely to be male, to have graduated from a medical school outside the United States, and to have been trained in the 1960s or 1980s rather than the 1970s. They were more likely to provide medications than psychotherapy, to practice at private rather than state and county public hospitals, to treat patients with affective and organic disorders, and to practice in a county containing an academic medical center. CONCLUSIONS: Demographic and training characteristics significantly influence whether a psychiatrist uses ECT. Opposing trends in the U.S. psychiatric workforce could affect the availability of the procedure. Expanding training opportunities for ECT and making education, training, and testing more consistent nationwide could improve clinicians' consensus about ECT and narrow variation in its use.

Antibody production and growth of mouse hybridoma cells in Nutridoma media supplements.

Traditionally, cell culturists have relied upon the addition of serum to culture medium for the growth and maintenance of cell lines. However, many aspects of the use of serum in tissue culture are problematic. Cell culture supplements that circumvent the need for serum are readily available and provide a consistent protein composition. This defined environment allows the antibody to be more easily purified from culture supernatants. Nutridoma media supplements were formulated to support the growth of lymphoblastoid cells in a defined culture environment. In this study, Nutridoma media supplements were tested in parallel with serum-containing cultures to determine if Nutridoma supplemented medium is effective in supporting hybridoma cell growth and antibody production in three hybridoma cell lines. Data, based on cell growth and antibody production, show the importance of basal media selection when serum is replaced with Nutridoma media supplements. SDS-PAGE results show that cell supernatants from Nutridoma supplemented cultures contain very few contaminating proteins.

A highly sensitive, nonradioactive DNA labeling and detection system.

A highly sensitive method for detecting specific nucleotide sequences was recently developed. The method uses digoxigenin-labeled nucleic acid probes for hybridization to immobilized target nucleic acids. Probes can be labeled by the random-primed method, nick translation, oligonucleotide tailing, cDNA synthesis, photodigoxigenin or SP6/T7/T3 polymerase-mediated transcription. Hybrids are detected by an enzyme-linked immunoassay using an anti-digoxigenin antibody conjugate. Visualization of the bound antibody is accomplished by an enzymatic color reaction, enzymatic chemiluminescent reaction or immunofluorescence, depending on the antibody conjugate and enzymatic substrate used. Here we report the successful application of this technology in the detection of specific cloned DNA in colony and plaque hybridizations, specific detection of a single mRNA species in Northern blots and single-copy gene detection in genomic Southern blots.