Change of the degree of septal hypertrophy in hypertrophic obstructive cardiomyopathy under procainamide treatment. A case report

The authors describe a patient with hypertrophic obstructive cardiomyopathy (HOCM) with decrease in septum thickness following procainamide treatment.

Acute effects of summer air pollution on respiratory symptom reporting in children

A daily diary of respiratory symptoms was collected from the parents of 1,844 school children in six U.S. cities to study the association between ambient air pollution exposures and respiratory illness. A cohort of approximately 300 elementary school children in each of six communities were asked to keep a daily log of the study child's respiratory symptoms for one year. Daily measurements of ambient sulfur dioxide, nitrogen dioxide, ozone, inhalable particles (PM10), respirable particles (PM2.5), light scattering, and sulfate particles were made, along with integrated 24-h measures of aerosol strong acidity. The analyses were limited to the five warm season months between April and August. Significant associations were found between incidence of coughing symptoms and incidence of lower respiratory symptoms and PM10, and a marginally significant association between upper respiratory symptoms and PM10. There was no evidence that other measures of particulate pollution including aerosol acidity were preferable to PM10 in predicting incidence of respiratory symptoms. Significant associations in single pollutant models were also found between sulfur dioxide or ozone and incidence of cough, and between sulfur dioxide and incidence of lower respiratory symptoms.(ABSTRACT TRUNCATED AT 250 WORDS)

Passive smoking exposure in adults and chronic respiratory symptoms (SAPALDIA Study). Swiss Study on Air Pollution and Lung Diseases in Adults, SAPALDIA Team

The association between passive exposure to tobacco smoke and respiratory symptoms was examined in a sample of 4,197 never-smoking adults. They constituted the never-smoking subsample of a random sample of 9,651 adults (age, 18 to 60 yr) in eight areas in Switzerland. Information on passive smoking exposure and standardized questions on respiratory symptoms were obtained via a questionnaire administered by trained examiners. After controlling for age, sex, body mass index (BMI), study area, atopy, and parental and sibling history, passive smoking exposure was associated with an elevated risk of wheezing apart from colds (odds ratio [OR] = 1.94, 95% CI = 1.39 to 2.70), an elevated risk of bronchitis symptoms (OR = 1.59, 95% CI = 1.17 to 2.15), an elevated risk of symptoms of chronic bronchitis (OR = 1.65, 95% CI = 1.28 to 2.16), an elevated risk of dyspnea (OR = 1.45, 95% CI = 1.20 to 1.76), and an elevated risk of physician diagnosed asthma (OR = 1.39, 95% CI = 1.04 to 1.86). It was not associated with any increased risk of allergic rhinitis including hayfever. Adding a variable for low educational level, excluding subjects whose mother ever smoked or subjects with end-expiratory CO levels > or = 7 ppm, and controlling for paternal smoking during childhood or occupational exposure had little impact on the association. The association of passive smoking exposure with dyspnea, wheeze, and asthma showed evidence of a dose-dependent increase with hours per day of exposure, whereas association with symptoms of bronchitis was stronger with years of exposure.(ABSTRACT TRUNCATED AT 250 WORDS)

The relationship of dietary fish intake to level of pulmonary function in the first National Health and Nutrition Survey (NHANES I)

Eicosapentaenoic acid (EPA), which predominates in marine fish, tends to counteract and inhibit the uptake and incorporation of arachidonic acid and membrane phospholipids and dilute arachidonic acid as a potential substrate for oxidation. Thus, fish intake may be protective for the occurrence of asthma and other pulmonary diseases. We wanted to examine the relationship between the effect of chronic dietary intake to fish and its relationship to level of pulmonary function. We performed this analysis using data from the First National Health and Nutritional Examination Survey (NHANES I). A detailed subsample of 2,526 adults had a medical history questionnaire, that included a 24-hour dietary recall, and performed spirometric examination. Log of forced expiratory volume in one second (FEV1) served as a dependent variable in regression analysis which included an adjustment for height, age, cigarette smoking and gender. When added to the regression model including the above variables dietary fish intake showed a protective association with FEV1 (beta = 0.008 +/- 0.004, p = 0.028). When smokers were excluded from the analysis, the effect of fish intake on pulmonary function appeared to increase slightly (beta = 0.0108 +/- 0.006, p = 0.61). These data suggest that chronic dietary intake of fish is associated with higher levels of pulmonary function and is consistent with the hypothesis of an effect of fish oil on arachidonic acid metabolism.

Varicella hepatitis: a fatal case in a previously healthy, immunocompetent adult. Report of a case, autopsy, and review of the literature

Varicella, usually a benign infection of childhood, is known to be associated with more serious complications, especially in adults and immunocompromised patients. Of these, varicella pneumonitis is the most common. Primary varicella hepatitis has been described, though rarely, in immunocompromised patients. We present a case of a previously healthy human immunodeficiency virus-negative 26-year-old immigrant from El Salvador in whom primary varicella developed that rapidly progressed to fulminant hepatic failure, disseminated intravascular coagulation, and death. Autopsy revealed evidence of varicella in the liver, adrenal glands, and myometrium. To our knowledge, this is the first report of a fatal case of varicella hepatitis in a previously healthy, immunocompetent patient.

Air pollution and hospital admissions for the elderly in Detroit, Michigan

Several studies in recent years have suggested that exposure to airborne particles and to ozone are associated with increases in respiratory hospital admissions. Few of those studies have used inhalable particles as their measure of exposure, and the studies did not always examine both particle and ozone exposure. This study examined the association between both PM10 and ozone and respiratory hospital admissions for persons 65 yr of age and older in the Detroit, Michigan, metropolitan area during the years 1986 to 1989. After controlling for seasonal and other long-term temporal trends, temperature, and dew point temperature, both PM10 (RR = 1.012, 95% CI = 1.019-1.004) and 24-h ozone concentrations (RR = 1.026, 95% CI = 1.040-1.013) were associated with daily admissions for pneumonia. The relative risks are for a 10-microgram/m3 increase in PM10 and a 5-ppb increase in 24-h ozone concentration and from models including both pollutants. Admissions for COPD other than asthma were associated with PM10 (RR = 1.020, 95% CI = 1.032-1.009) and ozone (RR = 1.028, 95% CI = 1.049-1.007) as well. Asthma admissions were not associated with either pollutant. Controlling for one pollutant did not effect the magnitude of the association with the other pollutant. The magnitude of these relative risks are very similar to those recently reported in Birmingham, Alabama, Ontario, and New York State. This suggests that the associations with both pollutants are likely to be causal.

Somatization in patients with dissociative disorders

OBJECTIVE

This study attempted to determine the prevalence of somatic symptoms, somatization disorder, and medical interventions in patients with dissociative disorders.

METHOD

Fourteen psychiatric inpatients with a DSM-III dissociative disorder were matched for age and gender with a comparison group of inpatients who reported few dissociative symptoms. All subjects were interviewed in a blind manner with the Dissociative Disorders Interview Schedule (this semistructured interview schedule includes a section on somatization disorder), and their hospital charts were reviewed to determine somatic symptoms and medical histories.

RESULTS

Sixty-four percent of the patients with dissociative disorders met DSM-III criteria for somatization disorder and reported an average of 12.4 somatic symptoms. None of the comparison patients met DSM-III criteria for somatization disorder, and these patients reported an average of 3.1 somatic symptoms. These differences between the two groups were significant. Significant differences were also found in the number of medical hospitalizations and consultations between the two groups. A significant correlation was found between the degree of dissociation and degree of somatization in patients with dissociative disorders.

CONCLUSIONS

The authors conclude that somatization disorder is a frequent and serious comorbid disorder among patients with dissociative disorders.

PM10, ozone, and hospital admissions for the elderly in Minneapolis-St. Paul, Minnesota

Several recent studies have reported associations between airborne particles and/or ozone and hospital admissions for respiratory disease. PM10 has rarely been used as the particle exposure measure, however. This study examined whether such an association could be seen in Minneapolis-St. Paul, Minnesota, which has daily monitoring data for PM10. Data on hospital admissions in persons aged 65 y and older were obtained from Medicare records for the years 1986 through 1989. Daily counts of admissions, by admit date, were computed for pneumonia (ICD9 480-487) and chronic obstructive pulmonary disease (COPD) (ICD9 490-496). Classification was by discharge diagnosis. Daily air pollution data from all monitoring stations for ozone and PM10 in Minneapolis-St. Paul were obtained, and the daily average for each pollutant was computed. An average of approximately six pneumonia admissions and two admissions for chronic obstructive pulmonary disease occurred each day. Poisson regression analysis was used to control for time trends, seasonal fluctuations, and weather. PM10 was a risk factor for pneumonia admissions (relative risk [RR] = 1.17, 95% confidence interval [CI] = 1.33-1.02) and COPD admissions (RR = 1.57, 95% CI = 2.06-1.20). Ozone was also associated with pneumonia admissions (RR = 1.15, 95% CI = 1.36-0.97). The relative risks are for an increase of 100 micrograms/m3 in daily PM10 and 50 ppb in daily ozone concentration. Several alternative methods for controlling for seasonal patterns and weather were used, including nonparametric regression techniques. The results were not sensitive to the methods. When days exceeding the National Ambient Air Quality Standard for either pollutant were excluded, the association remained for both pneumonia (RR = 1.18, 95% CI = 1.34-1.03 for PM10, and RR = 1.18, 95% CI = 1.41-0.99 for ozone) and COPD (RR = 1.54, 95% CI = 2.06-1.16 for PM10).

Accuracy of viscera slide detection of abdominal wall adhesions by ultrasound

Viscera slide is the normal, longitudinal movement of the intraabdominal viscera caused by respiratory excursions of the diaphragm. By detecting areas of restricted viscera slide, ultrasonic imaging was used to identify anterior abdominal wall adhesions prior to laparotomy or laparoscopy. Transcutaneous ultrasound examination was performed on 110 patients. A prediction of adhesions was made for each patient and then compared to the findings during subsequent laparotomy or laparoscopy. Only patients with previous abdominal surgery or history of peritonitis demonstrated adhesions. Sensitivity and specificity of viscera slide ultrasound in predicting adhesions were 90% and 92%. Nine out of 10 false results involved misinterpretation of ultrasound images of the lower one-third of the abdomen. Ultrasonic imaging of viscera slide is highly accurate in detecting abdominal wall adhesions. This technique is most useful in guiding the insertion of trocar in laparoscopic surgery, and as a noninvasive method in studying the formation of adhesions.

Phosphorylation of Thr642 is an early event in the processing of newly synthesized protein kinase C beta 1 and is essential for its activation

Earlier studies of a site-specific mutant of protein kinase C beta 1 (PKC beta 1) altered at Thr635 and Thr642 indicated that these phosphorylation sites are critical for enzymatic function (Zhang, J., Wang, L., Petrin, J., Bishop, W. R., and Bond, R. W. (1993) Proc. Natl. Acad. Sci. U.S.A. 90,6130-6134). To determine the contribution of the individual threonines, we report here on two site-specific mutants in which either Thr635 or Thr642 was changed to alanine. When transiently overexpressed in Cos cells wild-type PKC beta 1 exists in two forms: a Triton-insoluble form with high electrophoretic mobility and a slower migrating Triton-soluble form. Mutation at Thr642 (but not Thr635) results in production of only the fast-migrating form. [35S]Methionine pulse-chase labeling indicates that wild-type PKC beta 1 is synthesized as the fast-migrating form and is subsequently converted to the slow-migrating form. 32P labeling shows that only the slow-migrating form is a phosphoprotein. Mutation of Thr642 abolishes this phosphorylation. Finally, the Thr642 mutant PKC beta 1 lacks enzymatic activity and, when expressed in NIH 3T3 cells, reduces phorbol ester-induced c-fos promoter activity. These results indicate that Thr642 phosphorylation is an early event in the processing of newly synthesized PKC beta 1 and is required for enzymatic function. These results support a role for a PKC kinase in PKC processing and activation.

Societal benefits of reducing lead exposure

While sophistication in public health research has been increasing substantially in the past few decades, sophistication in decision making about public health and environmental issues has not been increasing in parallel. Measures that are inexpensive tend to be implemented and measures that are expensive tend not to be implemented by makers of public policy. That is often independent of the degree of public health protection afforded by the measures. Understanding and addressing this pattern is crucial to the control of lead exposure of critical populations. People are still exposed to lead in our society not because anyone believes that exposure is good, but because reducing exposure costs money. Maintaining exposure also has its costs, however. It is more difficult to measure them, and they are often ignored in decision making--but they are not small, and attempts to measure them have been made. The high cost of reducing lead exposure of critical populations is the reason that progress in reducing lead-paint exposure has been minimal in the 18 years since the passage of the Lead-Based Paint Poisoning Prevention Act and that it took from the time of the initial proposal in 1973 until 1986 before lead was substantially eliminated from gasoline. In its 1986 rule making, the EPA estimated that the elimination of lead from gasoline would cost more than $500 million per year. Removing leaded paint is estimated to cost billions of dollars. The difference is that the EPA promulgated its rule of removing lead from gasoline, whereas HUD has had little success in removing leaded paint from housing. One reason that the EPA was successful in implementing such an expensive regulation was that it provided detailed estimates of the health and welfare benefits that would accrue and the monetary value of some of the benefits. The EPA cost-benefit analysis demonstrated that the monetary benefits of its regulation far exceeded the costs. That neutralized the cost issue and focused the debate over the regulation on questions of timing. A detailed benefit analysis of reducing lead in drinking water has caused the EPA to consider tighter water lead standards than initially envisioned. Despite years of concern about the consequences of leaded paint poisoning, children continue to be poisoned by leaded paint because it will cost billions of dollars to abate the hazard, and demand for these dollars has lost out to competing needs.(ABSTRACT TRUNCATED AT 400 WORDS)

Complicated Marfan's syndrome with unusual longevity. A case history

The authors present a complicated case of Marfan's syndrome in an elderly woman with unusual longevity.

Using POSTDOC to recognize biomedical concepts in medical school curricular documents

Recognition of the biomedical concepts in a document is prerequisite to further processing of the document: medical educators examine curricular documents to discover the coverage of certain topics, detect unwanted redundancies, integrate new content, and delete old content; and clinicians are concerned with terms in patient medical records for purposes ranging from creation of an electronic medical record to identification of medical literature relevant to a particular case. POSTDOC (POSTprocessor of DOCuments) is a computer application that (1) accepts as input a free-text, ASCII-formatted document and uses the Unified Medical Language System (UMLS) Metathesaurus to recognize relevant main concept terms; (2) provides term co-occurrence data and thus is able to identify potentially increasing correlations among concepts within the document; and (3) retrieves references from MEDLINE files based on user identification of relevant subjects. This paper describes a formative evaluation of POSTDOC's ability to recognize UMLS Metathesaurus biomedical concepts in medical school lecture outlines. The "precision" and "recall" varied over a wide range and were deemed not yet acceptable for automated creation of a database of concepts from curricular documents. However, results were good enough to warrant further study and continued system development.

Metabolic disposition and elimination studies of a radiolabelled biodegradable polymeric implant in the rat brain

The metabolic disposition and elimination process of the anhydride co-polymer poly[1,3-bis(p-carboxy-phenoxypropane):sebacic acid] 20:80 [P(CPP:Sa)20:80] implanted in the rat brain was studied. Two polymers were prepared, one with [14C]SA and unlabelled CPP, and the other co-polymer with [14C]CPP and unlabelled SA. With these two polymers we were able to study the metabolic disposition of each monomer after polymer degradation. Polymer wafers loaded with N,N-bis(2-chloroethyl)-N-nitrosourea or without the drug were implanted in the rat brain. For the rats implanted with the [14C]SA-labelled polymer, approximately 40% of the radioactivity was found in the expired CO2, 10% in the urine, about 2% in the faeces and about 10% remained in the device 7 d after implantation. On the other hand, only 4% of the [14C]CPP monomer was eliminated by urine and faeces during this period. The drug-loaded polymer degraded faster than the blank polymer. This study supports the theory that the polymer is a biodegradable material that can be used for the direct and specific delivery of drugs into a targeted organ and can provide continued release of drugs over a period of time.

The behavioral effects of the stereoisomers of 4-methylaminorex, a psychostimulant, in the rat

In this study, we examined the effect of the isomers of the psychostimulant 2-amino-4-methyl-5-phenyl-delta 2-oxazoline (4-methylaminorex or 4-MAX) on behavior in rats. The s.c. administration of the stereoisomers of 4-MAX, trans-4S,5S, cis-4R,5S, cis-4S,5R and trans-4R,5R (0.3-3 mg/kg), produced a dose-dependent increase in locomotor activity. However, at a dose of 10 mg/kg, the isomers of 4-MAX produced an initial increase in locomotor activity followed by the appearance of stereotyped behaviors (continuous sniffing, chewing, head bobbing, etc.) then a subsequent phase of rebound-enhanced locomotor activity all over a time course of 4 hr. The rank order of potency for the stereoisomers of 4-MAX was: 4S,5S > 4R,5S =4S,5R < 4R,5R. To determine what neurotransmitter systems may mediate the action of 4-MAX, the ability of various receptor antagonists to block or attenuate the effect of trans-4S,5S-4-MAX (3 mg/kg s.c.) on locomotor activity was examined. The selective dopamine (DA) D1 antagonist (-)-trans-6,7,7a,8,9,13b-hexahydro-3-chloro-2-hydroxy-N-methyl-5H- benzo- [d]naph-thio[2,1b]azepine (SCH 39166) and the D2 receptor antagonist (-)-eticlopride significantly, attenuated the behavioral action of trans-4S,5S-4-MAX, whereas antagonists to serotonergic and adrenergic receptors were ineffective. These results suggest that the ability of 4S,5S-4-MAX to induce locomotor hyperactivity and stereotypical behaviors and to increase rearing durations is primarily mediated by DA receptors. To determine whether the action of 4-MAX is dependent upon 5-hydroxytryptamine or DA concentrations in nerve terminals, rats were pretreated with either reserpine, alpha-methyl-p-tyrosine or d,l-p-chlorophenylalanine. Both reserpine and alpha-methyl-p-tyrosine pretreatment markedly attenuated the locomotor activity produced by trans-4S,5S-4-MAX. Moreover, L-dopa partially reversed the inhibitory action of alpha-methyl-p-tyrosine on 4S,5S-4-MAX-induced behavioral activation. In contrast, the administration of d,l-p-chlorophenylalanine did not alter the behavioral responses produced by trans-4S,5S-4-MAX. Taken together, our results suggest that 4-MAX may increase several locomotor behaviors by inducing neuronal DA release, which subsequently interacts with dopaminergic receptors.

Experience with Endopap endometrial sampling in the cytodiagnosis of endometrial carcinoma and its precursor lesions. I. A correlative cytologic-histologic-hysteroscopic diagnostic pilot study

From June 1 through December 3, 1991, 146 women were referred to the Gynecology Outpatient Clinic of Nahariyya Medical Center for uterine bleeding and pathologic conditions. Their ages ranged from < 40 (26 patients) to > or = 60 (18 patients), with 60 (41%) in the 40-49 age group. An Endopap endometrial sampling pilot study was undertaken to find a correlative index between cytologic, histologic and hysteroscopic sampling methods as well as to investigate the possibility that Endopap sampling could avoid excessive use of nontherapeutic dilation and curettage. In 118 patients for whom concomitant cytologic and histologic specimens were available there was no statistically significant difference between the number of correct cytologic and histologic diagnoses of intrauterine pathology. Cytodiagnostic accuracy of the Endopap samples was expressed in terms of sensitivity (68.2%), specificity (80.7%), predictive value of a malignant test result (100%) and predictive value (PV) of an abnormal (hyperplasia) test result (73.2%). The lower values for sensitivity, specificity and PV in this study as compared with those in the literature were probably due to three attenuating factors: the relatively small number of patients (146), the fact that the cytodiagnostic accuracy for hyperplasia and precursor lesions of endometrial carcinoma is significantly lower than for histologic diagnosis, and the presence of 15 (10.3%) inadequate cytologic specimens. The results did tend to concur with the range of reported results. It is recommended that Endopap sampling be employed in cases of medically and anatomically contraindicated dilation and curettage--e.g., cervical canal stenosis and intrauterine adhesions (Asherman's syndrome)--in monitoring perimenopausal and postmenopausal patients on estrogen replacement therapy and in obese women, diabetics and hypertensives at risk of developing endometrial hyperplasia. The study also showed that the combined hysteroscopic and Endopap techniques could result in increased rates of sensitivity and specificity.

Cigarette smoking and peripheral blood leukocyte differentials

Cigarette smoking increases the total peripheral blood leukocyte count but its effect on the differential cell count in peripheral blood is largely unexplored. We studied 6138 subjects between the ages of 30 and 74 years who were seen as part of the First National Health and Nutrition Examination Survey in 1971 to 1974 to assess the relationship of current smoking status, number of cigarettes smoked per day, pack-years of smoking, and years since quitting, to the absolute and percent count of neutrophils, eosinophils, lymphocytes, and monocytes in peripheral blood. The relationship of cigarette smoking to the differential cell counts was adjusted for age, race, sex, and obesity by multiple regression. Pack-years smoked, years since quitting, and current number of cigarettes smoked per day were all independent predictors of the absolute neutrophil count and of the absolute lymphocyte count. Number of cigarettes smoked per day was the only smoking variable predictive of the absolute monocyte count and the absolute eosinophil count. When differential cell counts were considered as a percent of total leukocytes, the results were somewhat different. Neutrophils were disproportionately increased by current number of cigarettes smoked per day. Increased cigarette smoking decreased the proportion of white blood cells that were lymphocytes or eosinophils. Other smoking variables had no influence on percent counts for the specific white cell types in peripheral blood. These data suggest that the effect of cigarette smoking on differential cell counts is not uniform and is primarily influenced by current smoking behavior, although long-lasting effects of past smoking are also evident.

Low-level lead exposure and children's IQ: a meta-analysis and search for a threshold

To assess the strength of the association between blood lead and children's IQ, a meta-analysis of the studies examining the relationship in school age children was performed. Emphasis was given to the size of the effect, since that allows comparisons that are informative about potential confounding and effect modifiers. Sensitivity analyses were also performed. A highly significant association was found between lead exposure and children's IQ (P < 0.001). An increase in blood lead from 10 to 20 micrograms/dl was associated with a decrease of 2.6 IQ points in the meta-analysis. This result was robust to inclusion or exclusion of the strongest individual studies and to relaxing the age requirements (school age children) of the meta-analysis. Adding eight studies with effect estimates of 0 would still leave a significant association with blood lead (P < 0.01). There was no evidence that the effect was limited to disadvantaged children and there was a suggestion of the opposite. The studies with mean blood lead levels of 15 micrograms/dl or lower in their sample had higher estimated blood lead slopes, suggesting that a threshold at 10 micrograms/dl is implausible. The study with the lowest mean blood lead level was examined using nonparametric smoothing. It showed no evidence of a threshold down to blood lead concentrations of 1 microgram/dl. Lead interferes with GABAergic and dopaminergic neurotransmission. It has been shown to bind to the NMDA receptor and inhibit long-term potentiation in the hippocampal region of the brain. Moreover, experimental studies have demonstrated that blood levels of 10 micrograms/dl interfere with a broad range of cognitive function in primates. Given this support, these associations in humans should be considered causal.

Air pollution and hospital admissions for the elderly in Birmingham, Alabama

Several studies have reported associations between airborne particles and/or ozone and hospital admissions for respiratory disease. This study examined whether such an association could be seen in Birmingham, Alabama, one of the few cities in the United States with daily monitoring of inhalable particles. Daily counts of hospital admissions were computed by date of admission from Medicare records for pneumonia and chronic obstructive pulmonary disease for the years 1986-1989. Classification was by discharge diagnosis. The daily average of ozone and particulate matter with an aerodiameter of < or = 10 microns (PM10) from all monitoring stations in Birmingham was computed. Approximately six admissions for pneumonia and two for chronic obstructive pulmonary disease were observed each day. In Poisson regression analysis controlling for time trends, seasonal fluctuations, and weather, inhalable particles were a risk factor for admission for pneumonia (for an increase of 100 micrograms/m3 in daily concentration, relative risk (RR) = 1.19, 95% confidence interval (CI) 1.07-1.32) and chronic obstructive pulmonary disease (RR = 1.27, 95% CI 1.08-1.50). The results were not sensitive to alternative methods for controlling for seasonal patterns and weather, nor to the exclusion of very hot or cold days. Ozone was more weakly associated with admissions for pneumonia, with a 2-day lag (RR = 1.14, 95% CI 0.94-1.38), and for chronic obstructive pulmonary disease, with a 1-day lag (RR = 1.17, 95% CI 0.86-1.60). The risks are for an increase in ozone exposure of 50 parts per billion. Tests for nonlinearity in the relation between inhalable particles and admissions were not significant, and nonparametric smoothing found no evidence of a threshold in the relation.

Growth hormone induces a DNA binding factor related to the interferon-stimulated 91-kDa transcription factor

Signaling mechanisms leading to regulation of gene transcription by growth hormone (GH) and other molecules that signal via the cytokine receptor family have been elusive. Based upon recent findings that GH and interferons activate JAK family tyrosine kinases, we have identified a novel signaling pathway leading from the GH receptor to the nucleus. We report that in 3T3-F442A fibroblasts, GH stimulates tyrosyl phosphorylation of a protein recognized by antibody to p91, a component of DNA-binding complexes that are activated by tyrosyl phosphorylation in response to interferons alpha and gamma. In addition, a GH-inducible DNA binding factor (GHIF) is identified that binds to the c-sis-inducible element of the c-fos promoter. GHIF contains a protein antigenically related to p91 and is tyrosyl-phosphorylated. These findings indicate that in signaling between their receptors and the nucleus, GH and interferons utilize related or identical components, including JAK family tyrosine kinases and proteins in the p91 family. When combined with recent findings that many members of the cytokine receptor family activate JAK kinases, including some cytokines that activate p91-related proteins, these findings suggest that signaling pathways involving JAK kinases and p91 family members may be broadly distributed.