Switch from fetal to adult hemoglobin is associated with a change in progenitor cell population.

To examine the switch from fetal to adult hemoglobin at the cellular level, erythroid progenitor cells from newborn infants and adults were cultured in methyl cellulose with erythropoietin. Individual erythroid colonies were labeled with [3H]leucine at various times, and globin synthesis patterns examined by gel electrophoresis and fluorography. The percent gamma- or beta-globin synthesis was determined from the total of gamma + beta, and the percent G gamma from the total of G gamma + A gamma. The nonparametric correlation coefficients of percent G gamma with percent gamma or beta were obtained. Each group of colonies at each time point was examined separately. In colonies from adult blood, the proportion of G gamma-synthesis did not correlate with the proportion of gamma-synthesis. Colonies from newborn blood fell into two groups. Those that developed from relatively mature progenitor cells, and were seen on day 14, showed a strong negative correlation of G gamma with beta-globin synthesis. However, those newborn colonies that developed from immature progenitors, and were seen later in culture (days 17 and 21), showed no correlation of G gamma with beta-synthesis. These findings are compatible with a clonal model for hemoglobin switching. Fetal progenitors, in which G gamma- and beta-syntheses are negatively correlated, are gradually replaced during ontogeny by adult progenitors. The adult progenitors produce more beta (less gamma), and the proportions of G gamma- and gamma- or beta-synthesis are not correlated.

Investigations of the simian ontogenic switch from fetal to adult hemoglobin at the progenitor cell level.

The ontogenic switch from fetal to adult hemoglobin could result from discontinuous events, such as replacement of fetal erythroid progenitor cells by adult ones, or gradual modulation of the hemoglobin program of a single progenitor cell pool. The former would result in progenitors at midswitch with skewed fractional beta-globin synthesis programs, the latter in a Gaussian distribution. For these studies, we obtained bone marrow from rhesus monkey fetuses at 141-153 d (midswitch). Mononuclear cells were cultured in methyl cellulose with erythropoietin, and single BFU-E-derived colonies were removed and incubated with [3H]leucine. Globin synthesis was examined by gel electrophoresis and fluorography. The beta-globin synthesis pattern of single fetal colonies was skewed, and did not fit a normal distribution. The fetal pattern resembled the pattern of an artificial mixture of fetal and adult progenitors, suggesting that the fetal progenitor pool could contain populations with different beta-globin programs. This non-Gaussian distribution in the progenitors of midswitch fetuses is consistent with a discontinuous model for hemoglobin switching during ontogeny.

Effects of treatment with 5-azacytidine on the in vivo and in vitro hematopoiesis in patients with myelodysplastic syndromes.

The myelodysplastic syndrome (MDS) comprises a group of clonal hematopoietic disorders derived from an abnormality affecting a multipotent hematopoietic stem cell. Despite trials testing numerous agents in patients with MDS, no single drug has yet emerged as the accepted standard of treatment. Observation and supportive care with blood products and antibiotics, when necessary, continue to be the mainstays of therapy. We administered 5-azacytidine, a cell-cycle specific ring analog of the pyrimidine nucleoside cytosine, as a continuous intravenous infusion, 75 mg/m2 per day for 7 days every 4 weeks. Patients had refractory anemia with excess blasts (RAEB) or refractory anemia with excess blasts in transformation (RAEB-T). Responses were seen in 21 (49%) of 43 evaluable patients: five (12%) in complete remission (CR, complete normalization of bone marrow and peripheral blood counts); 11 (25%) in partial remission (PR, > or = 50% restoration of the deficit from normal of all three peripheral blood cell lines, elimination of transfusion requirements, and a decrease in percentage bone marrow blasts by > or = 50% from prestudy values); five (12%) improved (> or = 50% restoration in the deficit from normal of one or more peripheral blood cell lines and/or a > or = 50% decrease in transfusion requirements). A trilineage improvement (CR and PR) occurred in 37% of the patients. The median survival for all patients was 13.3 months and the median duration of remission for those with CR and PR was 14.7 months. Mild to moderate nausea and/or vomiting was the most common side effect (63%). Myelosuppression, either bone marrow hypoplasia or drug related cytopenias requiring a reduction in the dose of azacitidine, occurred in only 33% of the patients. Prior to treatment, bone marrow erythroid progenitor cells were assayed in vitro. Colonies derived from erythroid burst-forming units (BFU-e) were undetectable in one patient and reduced in two. The number of colonies derived from erythroid colony-forming units (CFU-e)) were also reduced in two of the three patients. In the two patients with detectable colony growth prior to treatment, colony number decreased by day 8 of the first cycle, followed by a subsequent increase. Continued treatment with azacitidine led to normalization of the number of CFU-e derived colonies as well as an increase in the number of BFU-e derived colonies. This improvement in erythroid colony number correlated with the spontaneous rise in hemoglobin levels and red cell transfusion independence.(ABSTRACT TRUNCATED AT 400 WORDS)

In vitro erythropoiesis in polycythemia vera and other myeloproliferative disorders.

PV is a myeloproliferative disorder characterized by an elevated hematocrit and red blood cell mass. In vitro hematopoietic culture systems have been used extensively to characterize the cellular defect in PV. Erythroid progenitor cells from PV patients exhibit characteristic endogenous erythroid colony growth in serum-containing semisolid culture medium. These endogenous erythroid colonies can be used as a diagnostic tool to distinguish PV from other myeloproliferative disorders and secondary erythrocytosis. Both EPO independence and exquisite EPO sensitivity are mechanism which have been proposed to explain the growth of endogenous colonies. In contrast with normal erythroid progenitor cells which have both high and low affinity EPO-R, PV erythroid cells have only low affinity EPO-R, Molecular analyses did not reveal mutations in the PV EPO-R. These findings have failed to clarify the role of EPO in the etiology of PV. PV hematopoietic progenitor cells also exhibit increased sensitivity to the hematopoietic growth factors GM-CSF, IL-3, and SCF. As with EPO-R studies, examination of IL-3 and SCF receptors on PV erythroid cells has not identified mechanisms underlying the observed increased sensitivities to these hematopoietic growth factors. The recent development of a truly serum-free culture system has led to the observation that PV progenitor cells are more than 100-fold more sensitive to IGF-1 than are normal progenitor cells. In addition, the IGF-1 receptor on PV progenitor cells exhibits increased basal phosphorylation and a hypersensitivity and hyperresponsiveness to IGF-1 with respect to tyrosine phosphorylation. Thus in PV, hypersensitivity to several hematopoietic growth factors may result in hyperproliferation of hematopoietic cells. This hypersensitivity ma be due to a defective intracellular mechanism common to these hematopoietic growth factors.

Coryneform group A-4 endophthalmitis. An experimental animal model.

Diphtheroids, members of the coryneform family of bacteria, increasingly have been recognized as the cause of serious ocular diseases. After isolation of coryneform group A-4 from two patients with delayed endophthalmitis after cataract extraction and intraocular lens implantation, 10(7) organisms were injected into the vitreous of seven New Zealand white rabbits, producing endophthalmitis in all eyes inoculated. Coryneform group A-4 subsequently was isolated in six of seven eyes receiving 10(7) organisms, proving Koch's postulates. Five of these seven eyes were treated with a single dose of intravitreal gentamicin, and three eyes remained culture positive. Eyes inoculated with 10(5) or 10(2) coryneform group A-4 organisms had transient anterior chamber and vitreal inflammation; all vitreous cultures were negative. These studies demonstrate that coryneform group A-4 endophthalmitis can be reproduced in an animal model and that gentamicin may not sterilize an eye infected with this organism. Future studies are needed to determine the optimum antibiotic regimen for treatment of this type of endophthalmitis.

Comparison of erythroid progenitor cell growth in vitro in polycythemia vera and chronic myelogenous leukemia: only polycythemia vera has endogenous colonies.

The ability of erythroid cultures to distinguish among myeloproliferative disorders was examined. We studied 14 patients with polycythemia vera (PV), 11 with chronic myelogenous leukemia (CML), four with non-PV erythrocytosis, two with agnogenic myeloid metaplasia, as well as three normal fetuses and greater than 25 normal adults. Endogenous, i.e. grew without added erythropoietin, bone marrow CFU-E-derived colonies were observed in all but one PV patient. However, endogenous blood BFU-E-derived bursts were observed in only eight of 14 PV patients. Endogenous erythroid colonies were not seen in cultures from any normal adults or fetuses, or patients with CML, erythrocytosis, or myeloid metaplasia. In PV, relative HbF synthesis was always greater in cultures without erythropoietin, while in cultures from all other patients relative HbF synthesis was similar to that observed in cultures from normal individuals. We conclude that PV and CML are distinguishable in culture since CML patients do not have endogenous growth. Most important, endogenous bone marrow CFU-E-derived colonies are the only consistently unique observation in patients with PV, and endogenous CFU-E- and BFU-E-derived colonies and bursts are not uniformly observed in PV blood cultures. In-vitro studies of erythropoiesis to confirm the diagnosis of PV, therefore, require marrow when endogenous colonies and bursts are absent from blood cultures.

Stripping of Descemet's membrane associated with intraocular lens implantation.

Stripping of Descemet's membrane (DM) occurred during intraocular lens implantation in three patients. We repositioned and anchored DM with an intracameral air bubble and through-and-through No. 10-0 nylon sutures. The favorable visual results achieved in cases of large, scrolled, nonplanar detachments reinforce the advantage of surgical repositioning. Descemetopexy with reverse through-and-through sutures in a "closed system" is recommended.

Coryneform endophthalmitis. Two case reports.

Recent clinical studies have emphasized the importance of diphtheroids, previously regarded as nonpathogenic bacteria or contaminants, as causes of ocular disease. We encountered two patients with endophthalmitis following cataract extraction and anterior chamber intraocular lens implantation. Both patients had previously been treated with subconjunctival and/or oral corticosteroids for presumed sterile endophthalmitis. Vitreous cultures in each case yielded pure growth of a diphtheroid that was subsequently identified as coryneform group A-4. The clinical response to standard intraocular therapy with gentamicin and cefazolin was delayed, although both patients eventually had restoration of functional vision. A comparison of the antibiotic minimum inhibitory and minimum bactericidal concentrations of the isolates may help to explain the delayed response to therapy seen in these two patients.

Serum lysozyme in sarcoid uveitis.

In a study of 100 patients, the mean serum lysozyme value for patients with sarcoidosis and active uveitis was elevated, while the mean value for patients with inactive sarcoidosis and inactive uveitis was within the normal range. The mean value for patients with a clinical picture of sarcoid uveitis, but without an established diagnosis of sarcoidosis, was high. In patients with ophthalmologic findings compatible with sarcoidosis, but without radiologic, immunologic, or other clinical evidence of the disease, an elevated serum lysozyme level may be indicative of sytemic disease.

Keratopathy after oral administration of tilorone hydrochloride.

Two patients given tilorone HCl orally for varying periods of time had clinical and histopathologic ocular changes. Retrospective study of 14 cancer patients who were taking tilorone HCl orally revealed that three patients had similar ophthalmic findings accompanied by the appearance of blue halos around pinpoint light sources. Examination revealed a diffuse clouding of the epithelium sometimes associated with subepithelial infiltrates. Abnormalities seen histologically included cloudy swelling of the epithelium and cytoplasmic inclusions. By electron microscopy these were found to be myelinoid bodies. Gas chromatography and mass spectrophotometry showed that tilorone HCl was present in the cornea and conjuctiva. Visual acuity was not affected and these changes were slowly reversible with the cessation of therapy. Biomicroscopic and conjunctival cytologic examination may serve to indicate the drug's storage and potential damage in the body.

Bilateral cytomegalovirus panuveitis after high-dose corticosteroid therapy.

A 30-year-old previously healthy woman who recieved immunosuppressive doses of corticosteroids developed an unusual culture-proved cytomegalovirus panuveitis bilaterally. The atypical clinical course was marked by bilateral exudative detachements with minimal evidence of retinitis. Any patient receiving blood transfusions and immunosuppressive doses of corticosteroids is potentially at risk for developing ocular cytomegalovirus infection, and the clinical presentation of the ocular infection may be atypical.

The effectiveness of psychological interventions in competitive sport.

The use of psychological interventions in competitive sport to enhance performance has become increasingly popular. However, the effectiveness of these interventions has been questioned by some sports psychologists. In general, educationally-based psychological interventions have produced significant increases in performance. Specifically, it was found that 38 of the 45 studies examined (85%) had found positive performance effects, although causality could only be inferred in 20 of these studies. These interventions could be classified as relaxation-based, cognitive, cognitive-behavioural or behavioural in nature. Although general support was provided for the effectiveness of psychological interventions in competitive sports, a number of methodological shortcomings limit the application of the findings. For example, future intervention research in competitive sport should employ more detailed manipulation checks, include follow-up assessments beyond a mere post-test, include placebo-control groups to control for expectancy effects and include more diverse samples. In addition to the empirical intervention research, recent research employing qualitative methodologies has greatly added to our understanding of the types of interventions and what type of sport psychology consultants most positively affect performance enhancement, as well as the personal growth of athletes. Continued quantitative and qualitative research needs to be conducted so that a better understanding is gained of how to conduct psychological interventions with athletes that will enhance performance as well as personal growth.

Nocardial endophthalmitis: report of two cases studied histopathologically.

We report two cases of nocardial endophthalmitis. Case 1 is a 66-year-old man whose left eye was enucleated about one month after onset of decreased vision. Ophthalmoscopic examination disclosed multiple choroidal masses. Six weeks before the onset of ocular manifestations he had undergone a prolonged carotid endarterectomy with intraoperative complications. The source of the ocular infection was probably exogenous. Case 2 is a 49-year-old woman who had systemic sclerosis (scleroderma) with severe pulmonary insufficiency. She had received moderate doses of corticosteroids. Seventeen months after initiation of therapy she developed ocular manifestations leading to enucleation of the eye one month later. Histopathologically, the enucleated eyes in both cases showed numerous branching, Gram-positive, filamentous organisms involving mainly the plane of Bruch's membrane and the subretinal space. The nosological and microbiological aspects of nocardiosis are reviewed.

Goal setting and performance in sport and exercise settings: a synthesis and critique.

Although goal setting research in industrial and organizational settings has been proliferating rapidly over the past 20 yr, it is only recently that sport psychologists begun to systematically test its effects in sport and exercise settings. However, the recent empirical literature in sport and exercise examining the relationship between goals and performance has been equivocal. Thus, the purposes of the present review are fourfold: (a) briefly review the industrial/organizational literatures concerning the relationship between goals and task performance; (b) review the literature testing the relationship between goals and performance in sport and exercise settings; (c) discuss methodological and interpretive limitations including the impact of mediating variables; (d) offer future directions for research.

Effect of antiviral drugs and hematopoietic growth factors on in vitro erythropoiesis.

BACKGROUND: The purpose of these studies was to improve our understanding of nucleoside analog, antiviral, drug-induced anemia in HIV infection. METHODS: Peripheral blood erythroid progenitor cells (BFU-E) from HIV-positive (HIV+) patients and normal donors were compared in methylcellulose cultures with erythropoietin, with and without antiviral drugs, and with and without the hematopoietic growth factors, stem cell factor (SCF), hemin, and interleukin-3 (IL-3). RESULTS: Normal numbers of BFU-E-derived colonies were observed in cultures from HIV+ patients (mean +/- 1 SD BFU-E/10(5) cells plated: normal = 14.1 +/- 7.9, HIV+ = 17.2 +/- 14.2, p = 0.39). The antiviral drugs zidovudine (AZT), dideoxyinosine (ddI), and didehydrodideoxythymidine (d4T) all inhibited erythroid colonies in HIV+ and normal cultures. AZT was the most erythropoietically inhibitory drug (AZT ID50, mean +/- 1 SD for normal cultures = 2.64 +/- 4.15 microM, for HIV+ cultures = 6.28 +/- 10.79 microM, p = 0.24). Hematologic toxicity was less with ddI and d4T. However, doses of ddI and d4T < or = 10 microM inhibited colony growth in 9/14 and 8/12 cultures, respectively, from HIV+ patients. CONCLUSIONS: Stem cell factor (SCF), hemin, and interleukin-3 (IL-3) increased colony growth in HIV+ and normal cultures. In control cultures, hematopoietic growth factors added singly increased growth 1.3- to 8-fold. Hematopoietic growth factors increased growth even in cultures containing antiviral drugs. In some instances growth factors restored growth to control levels. SCF, hemin, and IL-3 were most effective when combined.

Effects of hemin on erythropoiesis.

It is clear that in vitro hemin increases the number of blood BFU-E derived colonies from normal donors. This occurs with sickle donors as well, despite the increased levels of hemin in vivo in these patients. The effect of hemin on relative gamma globin synthesis is inconsistent, however. In a few cases, delayed addition of hemin led to increased gamma globin synthesis. In time course studies of cultures from normal donors, hemin added on day 0 shifted the day of peak colony number from 13-14 to 16-20 days. The temporal decline in gamma globin synthesis was not altered. In cultures from sickle donors we found that the time for maximal colony number was later than in normals, occurring at 16-20 days even without hemin, and was not further delayed by hemin. The relative proportion of gamma globin synthesis was higher on day 14 in the sickle than the normal cultures, and the temporal decline was somewhat slowed in the sickle cultures by hemin. The elevated gamma synthesis and the later time for peak colony growth in the sickle cultures suggest that the erythroid progenitors in the blood of the sickle patients are less mature than those from normal individuals. There are several possible explanations for the detection of increased numbers of colonies in cultures containing hemin. Hemin may delay the final maturation of erythroblasts within erythroid colonies, thus shifting the time of maximal growth. It may also increase the extent of final maturation, leading to more complete hemoglobinization of the erythroblasts within the colonies, and thus increasing the number of colonies that are eventually recognized as erythroid.(ABSTRACT TRUNCATED AT 250 WORDS)

The effects of success and failure on the patterning of neuromuscular energy.

Weinberg and Hunt (1976) demonstrated that high- and low-anxious subjects differed in their patterning of neuromuscular energy in performance under failure feedback. The present study extends these findings to conditions that involve success feedback. The Sport Competition Anxiety Test and State-Trait Anxiety Inventory were administered to distinguish A-State and A-Trait subjects, while EMG indicated qualitative aspects of throwing. High-and low-trait anxiety subjects received either success, failure, or no feedback. High-anxious subjects performed best under success feedback, and low-anxious subjects performed best after failure feedback. High-anxious subjects used more EMG energy before, during, and after the throw in all conditions, and success feedback was beneficial for high-anxious subjects. The results are discussed in terms of the inter-relationships between efficiency of neuromuscular energy, motor performance, and state anxiety.

The interrelationships between anxiety, motor performance and electromyography.

Much confusion in the research on anxiety and motor behavior is due to the failure to distinguish between anxiety as a transitory state and as a relatively stable state. In addition, researchers have been focusing on the end result of a motor act (performance) instead of investigating the quality of movement (patterns of energy organization) that make up the motor act. The State-Trait Anxiety Inventory was administered in this study to distinguish A-State and A-Trait subjects, while electromyography was used to investigate qualitative differences in motor behavior. High-anxious subjects performed significantly poorer than low-anxious subjects, and they used more energy over a longer period of time before, during, and after the performance than low-anxious subjects. The results were discussed in terms of efficiency of neuromuscular energy expenditure.

Motor performance under three levels of trait anxiety and stress.

In general, the interactive effects of trait anxiety and stress on motor performance have been neglected in assessing the viability of the inverted-U hypothesis. The present investigation tested the inverted-U hypothesis using three levels of trait anxiety and psychological stress. Performance results produced an inverted-U curve for the three levels of stress, with subjects in the moderate-stress condition displaying the highest performance. In addition, a significant trait anxiety x stress interaction indicated that high trait-anxious subjects performed best in the low-stress condition, while low trait-anxious subjects performed best in the high-stressed condition. The discussion concerns theories attempting to explain the relationship between anxiety and motor performance.

Combined granular-lattice ('Avellino') corneal dystrophy.

BACKGROUND/PURPOSE: In 1988, a report was published describing the histopathologic examination of corneal buttons of 4 patients who had undergone unilateral keratoplasty because of decreased vision caused by what had been diagnosed clinically as granular dystrophy. But on pathologic examination, lesions characteristic of both granular dystrophy and lattice dystrophy were found in each of the 4 corneal buttons. The patients came from 3 different families, each of which traced its origin to the Italian province of Avellino. We studied the clinical and histopathological features of 4 corneas affected by combined granular-lattice dystrophy, adding thereby to the total of 12 other corneas that have been so-described in the literature. METHODS: Two women underwent bilateral penetrating keratoplasty for what was diagnosed clinically as Reis-Bücklers dystrophy in the first patient, and as granular dystrophy in the second patient. We studied all 4 corneas pathologically, using both conventional hematoxylin and eosin stains as well as special histochemical techniques. RESULTS: All 4 corneas contained lesions characteristic of both granular dystrophy and lattice dystrophy, a circumstance that has given rise to the name "combined granular-lattice dystrophy." The patients are not known to be of Italian ancestry. CONCLUSIONS: Three clinical signs characterize combined granular-lattice dystrophy: (1) anterior stromal discrete, grayish-white deposits; (2) lattice lesions located in mid-stroma to posterior stroma; and (3) anterior stromal haze. Both clinically and histopathologically, the lattice lesions are of greater diameter than are those that occur in lattice dystrophy type I. In the past few years, striking advances have been made in understanding the genetics of combined granular-lattice dystrophy. The most recent of these was published just 2 months before the 1997 meeting of the American Ophthalmological Society, and establishes a common molecular origin for granular dystrophy, lattice dystrophy type I, Avellino dystrophy, and Reis-Bücklers dystrophy.