Zebrafish mdk2, a novel secreted midkine, participates in posterior neurogenesis

Patterning the neural plate in vertebrates depends on complex interactions between a variety of secreted growth factors. Here we describe a novel secreted factor in zebrafish, named mdk2, related to the midkine family of heparin-binding growth factors that is involved in posterior neural development. mdk2 is expressed shortly after the onset of gastrulation in the presumptive neural plate cells of the epiblast, and this expression is enhanced by exogenous retinoic acid. Ectopic expression of mdk2 enhances neural crest cell fates at the lateral edges of the caudal neural plate, concomitant with a repression of anterior structures and mesendodermal and ectodermal markers. Reciprocally, ectopic expression of a dominant negative mdk2 results in severe deficiencies of structures posterior to the midbrain-hindbrain boundary, with negligible effects on anterior structures. In these embryos, the expression of hindbrain and neural crest markers is strongly reduced, and the formation of posterior primary moto- and sensory neurons is blocked. Analyses in mutant zebrafish embryos shows that expression of mdk2 is independent of FGF8 and nodal-related-1 signaling, but is under negative control of BMP signaling. These data support the hypothesis that mdk2 participates in posterior neural development in zebrafish.

Genetic restriction of HIV-1 pathogenesis to AIDS by promoter alleles of IL10

IL10 is a powerful TH-2 cell cytokine produced by lymphoid cells that limits HIV-1 replication in vivo, ostensibly by inhibiting macrophage/monocyte and T-cell lymphocyte replication and secretion of inflammatory cytokines (IL1, TNFalpha, IL6, IL8, and IL12). A genetic epidemiological scan of patients enrolled in AIDS cohorts for candidate gene-linked short tandem repeat polymorphisms revealed significant genotype associations for HIV-1 infection and progression to AIDS with markers adjacent to and tracking (by linkage disequilibrium) common single nucleotide polymorphic variants in the IL10 promoter region. Individuals carrying the IL10-5'-592A (IL10-5'A) promoter allele possibly were at increased risk for HIV-1 infection, and once infected they progressed to AIDS more rapidly than homozygotes for the alternative IL10-5'-592 C/C (IL10-+/+) genotype, particularly in the later stages of HIV-1 infection. An estimated 25-30% of long-term nonprogressors (who avoid clinical AIDS for 10 or more years after HIV-1 infection) can be attributed to their IL10-+/+ promoter genotype. Alternative IL10 promoter alleles are functionally distinct in relative IL10 production, in retention of an avian erythroblastosis virus transcription factor recognition sequence and in binding to specific putative nuclear transcription factors, suggesting a potential mechanism whereby IL10-5'A down-regulation of inhibitory IL10 facilitates HIV-1 replication in vivo, accelerating the onset of AIDS.

[Doxycycline--the forgotten antibiotic]

BACKGROUND

Doxycycline is an broad-spectrum antimicrobial agent, it remains an inexpensive alternative for the treatment of community-acquired respiratory infections and urinary tract infections. Despite these clinical data the use of doxycycline has decreased during the last years.

PHARMACOLOGY

Adverse effects and resistance to therapy are infrequent and not different to fluoroquinolones and macrolide antibiotics. Gastrointestinal and phototoxic side effects are of importance. After oral administration 75% will be absorbed and largely eliminated by the hepatic and intestinal way. Contraindications are severe liver dysfunction and treatment in childhood.

CLINICAL INDICATIONS

Bacterial resistance to doxycycline has a low incidence in Germany. A therapeutic success can be expected in respiratory and urinary tract infections in about 80%. Doxycycline is the drug of choice for treating infections caused by Rickettsia, Borrelia, Ehrlichia. It shows good activity against Plasmodium falciparum as one part in a combination therapy. Daily costs of therapy are low, in oral administration DM 0.80 per day, in i.v. administration DM 22,-per day.

CONCLUSION

Despite competition from new antibiotics, doxycycline can retain an important place in the treatment of many infectious diseases.

Genetic heterogeneity and molecular epidemiology of GB virus C/hepatitis G virus in China

OBJECTIVE

The inter- and intrapatient genetic variation of GB virus C (GBV-C)/hepatitis G virus (HGV) was investigated to characterize the molecular epidemiologic profile of GBV-C/ HGV infection in China, an area endemic for viral hepatitis. The intrapatient variation of hepatitis C virus (HCV) from the same patients was compared to that of GBV-C/HGV.

STUDY DESIGN/METHODS

GB virus C/HGV RNA was amplified by polymerase chain reaction in 88 patients with hepatitis C, hepatitis B or presumed non-A-E hepatitis from three cities in China. Five clones of the GBV-C/HGV NS3 region were sequenced from each GBV-C/HGV RNA-positive patient. The corresponding region of HCV was also sequenced from patients co-infected with HCV. Representative sequences of the GBV-C/HGV NS3 region from each patient and those of isolates from other continents were subjected to phylogenetic analyses.

RESULTS

GB virus C/HGV was detected in 22 (25.25%) of 88 patients: 9 (21.4%) of 42 patients with presumed non-A-E hepatitis, 10 (27.7%) of 36 patients with hepatitis C, 3 (30.0%) in 10 patients with hepatitis B and C, and in none of 60 volunteer blood donors. The extent of nucleotide variation was less between Chinese isolates (2.4-17%; median, 10.4%) than between Chinese isolates and seven isolates from outside China (10.5-19.5%; median, 15.3%). Intrapatient sequence variation ranged from 0 to 1.75%, with a mean of 0.57 +/- 0.51%. Phylogenetic analysis grouped most Chinese isolates into four geographically specific clusters with a divergence of 10% to 16% from each other. The ratio of nonsynonymous to synonymous substitutions of GBV-C/HGV (Ka/Ks 0.019) was much lower than for HCV (0.071) in the same patients.

CONCLUSION

Chinese isolates of GBV-C/HGV are genetically distinct. There are local strains as well as shared strains between different locales. The extent of amino acid sequence conservation suggests strong selection against nonsynonymous substitutions in the GBV-C/HGV genome.

EGF infusion stimulates the proliferation and migration of embryonic progenitor cells transplanted in the adult rat striatum

Immature progenitor cells (generated by in vitro propagation) may provide a useful alternative to primary cells (from dissected embryonic tissue) for transplantation if their migratory and proliferative and differentiation properties can be controlled and directed in vivo. In this study E15 murine EGF-responsive progenitor cells were transplanted to the striatum of adult rats. Simultaneously, these animals received continuous infusion of either epidermal growth factor (EGF) or vehicle, to the lateral ventricle, for 8 days. In animals that received EGF, the transplanted progenitors migrated toward the lateral ventricle and proliferated, as evidenced by bromodeoxyuridine incorporation. Progenitor cells transplanted to rats that received vehicle infusions showed neither of these responses. In all animals, transplanted progenitors expressed an immature astrocyte or oligodendrocyte phenotype, the majority of cells being astrocytes. We conclude that EGF stimulates the migration and proliferation of murine progenitor cells in vivo, either directly or indirectly, but does not influence their phenotypic differentiation.

Primary structure and expression of the xiphophorus DNA-(cytosine-5)-methyltransferase XDNMT-1

Small aquarium fishes become increasingly important in the study of normal vertebrate development and disease. Differential DNA methylation might play a role in these processes. In the teleost Xiphophorus, a well-established animal model for melanoma formation, tumour-specific hypomethylation of the melanoma-inducing gene ONC-Xmrk has been observed. We have isolated a cDNA for the DNA-(cytosine-5)-methyltransferase XDNMT-1 from this organism, which encodes the first full-length protein from a fish species. Linkage analysis showed that Xdnmt-1 is different from the Xiphophorus tumour suppressor R, which is involved in the transcriptional repression of the ONC-Xmrk melanoma oncogene in healthy fish. As methylation has been implicated in the regulation of ONC-Xmrk expression, XDNMT-1 might play a role by acting up- or downstream of R. Expression analysis demonstrated that the Xdnmt-1 transcript is present in all adult tissues and cell lines tested. However, developing embryos show a spatially and temporally regulated expression pattern suggesting that the enzyme might play a role during development in fish.

Complex sensorimotor behavioral changes after terminal striatal 6-OHDA lesion and transplantation of dopaminergic embryonic micrografts

In this study sensorimotor behavioral changes were monitored in rats following bilateral 6-hydroxydopamine (6-OHDA) axon terminal lesion and uni- or bilateral implantation of embryonic dopaminergic (DA) micrografts. A total of 28 microg of 6-OHDA was distributed over four injection tracts in the dorsolateral part of the caudate-putamen (CPU) bilaterally followed 4 months later by the implantation of DA micrografts spread over seven implantation tracts placed within the denervated area. Bilaterally 6-OHDA-lesioned animals exhibited significantly reduced behavioral performance scores in tests of explorational and stepping behavior as well as in skilled forelimb use. However, in contrast to the established medial forebrain bundle (MFB) lesion model of PD, these animals showed a spontaneous recovery in the side falling and skilled forelimb behavior and no deficits in overnight locomotor activity at 6 months after the lesion. Unilateral DA micrografts elicited a substantial amphetamine-induced rotational bias contralateral to the graft, but led to a significant impairment of contralateral skilled forelimb use and reduced scores in overnight locomotor activity. Bilateral DA micrografts caused a significant, though partial, increase in explorational and backhand stepping behavior, but resulted also in a significant decrease in performance levels in overnight locomotor activity and skilled forelimb use on both paws. In conclusion, DA grafts placed ectopically in the CPU in the partial lesion model of PD result in a double innervation of the GABAergic striatal neurons, arising from the residual nigrostriatal DA projections of the host and from the graft-derived DA efferent fibers. These two DA fiber systems may indeed function in a cooperative and competitive manner depending on their respective and different afferent and efferent connections, which, in turn, may lead to positive or negative influences on basal ganglia function and behavioral performances. The different patterns of 6-OHDA lesion and transplant-induced behavioral changes demonstrated in the present study compared to the "classical" MFB lesion model of PD may thus provide further insights in the complex functional organization of the basal ganglia and, thereby, may help to further optimize restorative strategies for neurodegenerative diseases, such as Parkinson's disease.

Effects of plasma HIV RNA, CD4+ T lymphocytes, and the chemokine receptors CCR5 and CCR2b on HIV disease progression in hemophiliacs. Hemophilia Growth and Development Study

We have investigated the effects of plasma HIV RNA, CD4+ T lymphocytes and chemokine receptors CCR5 and CCR2b on HIV disease progression in hemophiliacs. We prospectively observed during follow-up 207 HIV-infected hemophiliacs in the Hemophilia Growth and Development Study. Plasma HIV RNA was measured on cryopreserved plasma from enrollment using the Chiron Corporation bDNA (version 2.0) assay. Genoytpe variants CCR2b-641 and CCR5-delta32 were detected using standard molecular techniques. Those with the mutant allele for CCR2b, and to a lesser extent CCR5, had lower plasma HIV RNA, and higher CD4+ T lymphocytes than did those without these genetic variants. After controlling for the effects of plasma HIV RNA and CD4+ T lymphocytes, those with the CCR2b mutant allele compared with those wild-type, had a trend toward a lower risk of progression to AIDS, adjusted relative hazard of 1.94 (95% confidence interval [CI], 0.9-4.18; p = .092), and AIDS-related death, relative hazard 1.97 (95% CI, 0.98-4.00; p = .059). We conclude that plasma HIV RNA, CD4+ T lymphocytes, and CCR genotypes are correlated, and the protective affect of CCR2b against HIV disease progression is not completely explained by plasma HIV RNA or CD4+ T-lymphocyte number.

Site-specific migration and neuronal differentiation of human neural progenitor cells after transplantation in the adult rat brain

Neural progenitor cells obtained from the embryonic human forebrain were expanded up to 10(7)-fold in culture in the presence of epidermal growth factor, basic fibroblast growth factor, and leukemia inhibitory growth factor. When transplanted into neurogenic regions in the adult rat brain, the subventricular zone, and hippocampus, the in vitro propagated cells migrated specifically along the routes normally taken by the endogenous neuronal precursors: along the rostral migratory stream to the olfactory bulb and within the subgranular zone in the dentate gyrus, and exhibited site-specific neuronal differentiation in the granular and periglomerular layers of the bulb and in the dentate granular cell layer. The cells exhibited substantial migration also within the non-neurogenic region, the striatum, in a seemingly nondirected manner up to approximately 1-1.5 mm from the graft core, and showed differentiation into both neuronal and glial phenotypes. Only cells with glial-like features migrated over longer distances within the mature striatum, whereas the cells expressing neuronal phenotypes remained close to the implantation site. The ability of the human neural progenitors to respond in vivo to guidance cues and signals that can direct their differentiation along multiple phenotypic pathways suggests that they can provide a powerful and virtually unlimited source of cells for experimental and clinical transplantation.

New class I and II HLA alleles strongly associated with opposite patterns of progression to AIDS

The genetics of resistance to infection by HIV-1 cohort consists of 200 slow and 75 rapid progressors to AIDS corresponding to the extremes of HIV disease outcome of 20,000 Caucasians of European descent. A comprehensive analysis of HLA class I and class II genes in this highly informative cohort has identified HLA alleles associated with fast or slow progression, including several not described previously. A quantitative analysis shows an overall HLA influence independent of and equal in magnitude (for the protective effect) to the effect of the CCR5-Delta32 mutation. Among HLA class I genes, A29 (p = 0.001) and B22 (p < 0.0001) are significantly associated with rapid progression, whereas B14 (p = 0.001) and C8 (p = 0.004) are significantly associated with nonprogression. The class I alleles B27, B57, C14 (protective), and C16, as well as B35 (susceptible), are also influential, but their effects are less robust. Influence of class II alleles was only observed for DR11. These results confirm the influence of the immune system on disease progression and may have implications on peptide-based vaccine development.

Intranigral transplants of GABA-rich striatal tissue induce behavioral recovery in the rat Parkinson model and promote the effects obtained by intrastriatal dopaminergic transplants

Intrastriatal transplantation of fetal ventral mesencephalon (VM) is currently explored as a potential clinical therapy in Parkinson's disease (PD). Although providing substantial benefit for the patient, behavioral recovery so far obtained with intrastriatal VM grafts is not complete. Using the 6-hydroxydopamine lesion model of PD, we show here that near-complete restoration of the striatal dopamine (DA) innervation can be achieved by multiple intrastriatal microtransplants of fetal DA cells; nevertheless, complete recovery in complex sensorimotor behaviors was not obtained in these animals. In line with the current model of basal ganglia function, this suggests that the lesion-induced overactivity of the basal ganglia output structures, i.e., the substantia nigra (SN) and the entopeduncular nucleus, may not be completely reversed by intrastriatal VM grafts. In the present study, we have transplanted fetal VM tissue or fetal striatal tissue, as a source of DA and GABA neurons, respectively, into the SN of DA-depleted rats. Intranigral VM grafts induced behavioral recovery in some sensorimotor behaviors (forelimb akinesia and balance tests), but the effect did not exceed the recovery observed after intrastriatal VM grafts. Intranigral grafts of striatal tissue induced a pattern of functional recovery which was distinctly different from that observed after intranigral VM grafts, and recovery in coordinated forelimb use in the paw-reaching test was even more pronounced than after intrastriatal transplantation of VM cells. Combined transplantation of DA neurons into the striatum and GABA-rich striatal neurons into the SN induced additive effects of behavioral recovery observed in the forelimb akinesia test. We propose that intranigral striatal transplants, by a GABA-mediated inhibitory action, can reduce the overactivity of the host SN projection neurons and can induce significant recovery in complex motor behavior in the rat PD model and that such grafts may be used to increase the overall functional efficacy of intrastriatal VM grafts.

Relation of plasma leptin to lipoproteins in overweight children undergoing weight reduction

BACKGROUND

In obese children, plasma leptin is elevated and correlates with the body mass index (BMI). In obese adults, plasma leptin decreases during weight reduction. Since the leptin system changes dynamically in puberty, we asked whether weight reduction in obese adolescents has similar consequences for plasma leptin as in overweight adults. In plasma, a portion of leptin is bound to several as yet uncharacterised proteins. We therefore studied the possible association of leptin with plasma lipoproteins.

SUBJECTS AND METHODS

We measured plasma leptin, lipoprotein cholesterol and apolipoproteins (apo) A-I and B in 34 obese children (age 12.5+/-1.9 y, relative BMI 165.0+/-28.1%) before and after three weeks of weight reduction in a dietary camp. Lipoprotein binding of endogenous and exogenously radiolabelled leptin was studied by preparative ultracentrifugation.

RESULTS

Plasma leptin was higher in obese children than in normal weight controls and fell from 16.5+/-9.8 ng/ml to 10.0+/-8.6 ng/ml after weight reduction (P < 0.001). In multivariate regression, relative BMI and apoA-I were significant predictors of baseline leptin and accounted for 38% (P = 0.003) and 15% (P = 0.006) of the variance of baseline leptin concentrations in obese children. Only the difference in plasma high-density lipoprotein (HDL)-cholesterol independently predicted the change of plasma leptin that was associated with weight reduction, explaining 29% of the variance of leptin changes (P = 0.0032). A substantial portion of both endogenous and exogenously labelled leptin was recovered with HDL isolated by ultracentrifugation.

CONCLUSIONS

We conclude that plasma leptin decreases in overweight children undergoing short term weight reduction. In obese children, plasma apoA-I and HDL-cholesterol are independent predictors of leptin concentrations during weight loss, respectively. In addition, HDLs transport a variable portion of leptin in the circulation.

Genetic acceleration of AIDS progression by a promoter variant of CCR5

The CCR5 gene encodes a cell surface chemokine receptor molecule that serves as the principal coreceptor, with CD4, for macrophage-tropic (R5) strains of human immunodeficiency virus-type 1 (HIV-1). Genetic association analysis of five cohorts of people with acquired immunodeficiency syndrome (AIDS) revealed that infected individuals homozygous for a multisite haplotype of the CCR5 regulatory region containing the promoter allele, CCR5P1, progress to AIDS more rapidly than those with other CCR5 promoter genotypes, particularly in the early years after infection. Composite genetic epidemiologic analyses of genotypes bearing CCR5P1, CCR5-Delta32, CCR2-64I, and SDF1-3'A affirmed distinct regulatory influences for each gene on AIDS progression. An estimated 10 to 17 percent of patients who develop AIDS within 3.5 years of HIV-1 infection do so because they are homozygous for CCR5P1/P1, and 7 to 13 percent of all people carry this susceptible genotype. The cumulative and interactive influence of these AIDS restriction genes illustrates the multigenic nature of host factors limiting AIDS disease progression.

Efficiency of cell culture derivation from blastula embryos and of chimera formation in the medaka (Oryzias latipes) depends on donor genotype and passage number

Embryonic stem (ES) cells from early vertebrate embryos only rarely retain their full developmental potential under in vitro culture conditions, but undergo differentiation and lose their ability for chimeric embryogenesis. This is reflected by the fact that the ES cell technology to date could only be fully developed in mice. In the fish Oryzias latipes, the medaka, one ES-like cell line, MES1, has been established which gives rise to a high frequency of somatic chimeras but a low degree of chimerism. Here we have tested the effect of donor genotype and cultivation time on the efficiency of cell culture derivation and on chimera formation. The HB12A, HB32C and HNI strains of medaka most efficiently and reproducibly give rise to blastula-derived cell cultures that produce pigmented chimeras in albino hosts. Seven chimeras grew to male or female adults with normal fertility, although none of them showed obvious donor germline contribution. During prolonged in vitro propagation the frequency of chimeras and the degree of chimerism dropped to a value retained in the long-term cultured MES1 cells. Obviously, genetic factors in host/donor compatibility and physiological changes during prolonged in vitro culture may compromise, but do not abolish, the developmental potential of medaka ES-like cells. Thus, elucidation of conditions that will expand the developmental potential of medaka blastula cell cultures should lead to a further improvement towards establishment of the ES cell technology in medaka.

[The results of radiotherapy in meningiomas with a high risk of recurrence. A retrospective analysis]

AIM

Retrospective assessment of the efficacy of radiation therapy for meningiomas with high risk for local recurrence.

PATIENTS AND METHODS

Records of 67 patients with meningiomas treated from 1974 to 1995 at 2 centres were analyzed. Follow-up time ranged from 0.8 to 213 months (median: 61 months). Radiation therapy was given either after local failure or after biopsy or subtotal resection. The ratio between malignant (n = 20) and benign (n = 47) meningioma was 1:2.4. Median age of the patients was 55 years (7 to 77 years). Radiation treatment was given at 1.5 to 2 Gy per fraction to 36 to 79.5 Gy. Survival rates were calculated by the Kaplan-Meier method. Statistical comparisons were performed with the log-rank test and the Cox proportional hazards model. The Bonferroni method was used to correct for multiple comparisons.

RESULTS

Five- and 10-year disease-free survival rates were 82% +/- 5% (standard error) and 70% +/- 9%. Local control rates at 5 and 10 years were 78% +/- 5% and 68% +/- 9%. In uni- and multivariate analysis histology, sex, total dose and center showed no significant influence on the results. Patients age was significant for local control (univariate p = 0.02; multivariate p = 0.03) and disease-free survival (univariate/multivariate p = 0.04). The postoperative tumor burden had a significant influence of disease-free survival (multivariate p = 0.04). After Bonferroni correction no significant influence was observed. We did not observe late side effects, especially brain necrosis.

CONCLUSIONS

Despite of the negative selection of our patients we observed high survival- and local control rates after radiation therapy. This underscores the role of radiation therapy in the treatment of meningiomas with high risk of local failure.

Plasma leptin levels: interaction of obesity with a common variant of insulin receptor substrate-1

Obesity is associated with insulin resistance and other major cardiovascular risk factors. A common amino acid polymorphism at codon 972 of the insulin receptor substrate-1 (IRS-1) has been shown to interact with obesity in the expression of insulin resistance. The plasma concentration of the adipocyte-specific hormone leptin is increased in obesity and is correlated with adipose tissue mass. Because in vitro studies demonstrated inhibitory effects of leptin on insulin signaling, leptin may be involved in obesity-associated insulin resistance. To gain insight into the relationship between insulin and leptin in obesity, we studied plasma leptin levels and several cardiovascular risk factors, as well as their modification by the IRS-1 codon 972 genotype, in 156 obese individuals and 131 lean control subjects. In both groups, 10% of the subjects were heterozygous for the IRS-1 codon 972 variant. Obese individuals harboring the IRS-1 variant displayed significantly lower plasma concentrations of leptin than obese subjects without the polymorphism (means, 26.7 versus 37.8 ng/mL, P<0.0293). In a subgroup of obese patients, leptin mRNA abundance was measured in the adipose tissue and was significantly lower in carriers of the IRS-1 variant than in subjects with the wild-type variant (P<0.0291). Our data suggest that insulin signaling influences plasma leptin concentrations at the mRNA expression level and argue against leptin as a major causative factor of insulin resistance.

Incorporation and glial differentiation of mouse EGF-responsive neural progenitor cells after transplantation into the embryonic rat brain

In vitro, epidermal growth factor (EGF)-responsive neural progenitor cells exhibit multipotent properties and can differentiate into both neurons and glia. Using an in utero xenotransplantation approach we examined the developmental potential of EGF-responsive cells derived from E14 mouse ganglionic eminences, cortical primordium, and ventral mesencephalon, after injection into the E15 rat forebrain ventricle. Cell cultures were established from control mice or from mice carrying the lacZ transgene under control of the promoters for nestin, glial fibrillary acidic protein (GFAP), or myelin basic protein (MBP). The grafted cells, visualized with mouse-specific markers or staining for the reporter gene product, displayed widespread incorporation into distinct forebrain and midbrain structures and differentiated predominantly into glial cells. The patterns of incorporation of cells from all three regions were very similar without preference for the homotopic brain areas. These results suggest that EGF-responsive progenitor cells can respond to host derived environmental cues, differentiate into cells with glial-like features, and become integrated in the developing recipient brain.

Dating the origin of the CCR5-Delta32 AIDS-resistance allele by the coalescence of haplotypes

The CCR5-Delta32 deletion obliterates the CCR5 chemokine and the human immunodeficiency virus (HIV)-1 coreceptor on lymphoid cells, leading to strong resistance against HIV-1 infection and AIDS. A genotype survey of 4,166 individuals revealed a cline of CCR5-Delta32 allele frequencies of 0%-14% across Eurasia, whereas the variant is absent among native African, American Indian, and East Asian ethnic groups. Haplotype analysis of 192 Caucasian chromosomes revealed strong linkage disequilibrium between CCR5 and two microsatellite loci. By use of coalescence theory to interpret modern haplotype genealogy, we estimate the origin of the CCR5-Delta32-containing ancestral haplotype to be approximately 700 years ago, with an estimated range of 275-1,875 years. The geographic cline of CCR5-Delta32 frequencies and its recent emergence are consistent with a historic strong selective event (e.g. , an epidemic of a pathogen that, like HIV-1, utilizes CCR5), driving its frequency upward in ancestral Caucasian populations.

Activation of the Xmrk proto-oncogene of Xiphophorus by overexpression and mutational alterations

Xmrk is a receptor tyrosine kinase closely related to the human EGF receptor. In the teleost fish Xiphophorus two versions of the Xmrk gene exist, an oncogene (ONC) and a proto-oncogene (INV). While ONC-Xmrk is the melanoma-inducing gene, INV-Xmrk appears not to be involved in transformation of pigment cells. To elucidate the mechanism that converts the proto-oncogene into a transforming oncogene a comparative analysis of the structure, expression and function of both versions of the gene was performed. In contrast to ONC-Xmrk which is expressed at high levels in melanoma cells, the proto-oncogene INV-Xmrk is ubiquitously expressed at very low levels indicating overexpression as one possible reason for tumorigenicity by ONC-Xmrk. As sequence comparison of the proto-oncogene and the oncogene revealed a number of amino acid changes, a possible effect of these mutations on the activation of the ONC-Xmrk receptor was determined. A constitutive activation of the oncogenic receptor was found and ectopic expression of INV-Xmrk after microinjection into medakafish embryos did not lead to the high tumour rate in transgenic fish as observed for the oncogene. Our data therefore suggest that overexpression of the receptor alone is not sufficient for melanoma induction, but that in addition activating mutations in ONC-Xmrk are responsible for its full tumorigenic potential.

Production of medakafish chimeras from a stable embryonic stem cell line

Embryonic stem (ES) cell lines provide a unique tool for introducing targeted or random genetic alterations through gene replacement, insertional mutagenesis, and gene addition because they offer the possibility for in vitro selection for the desired, but extremely rare, recombinant genotypes. So far only mouse blastocyst embryos are known to have the competence to give rise to such ES cell lines. We recently have established a stable cell line (Mes1) from blastulae of the medakafish (Oryzias latipes) that shows all characteristics of mouse ES cells in vitro. Here, we demonstrate that Mes1 cells also have the competence for chimera formation; 90% of host blastulae transplanted with Mes1 cells developed into chimeric fry. This high frequency was not compromised by cryostorage or DNA transfection of the donor cells. The Mes1 cells contributed to numerous organs derived from all three germ layers and differentiated into various types of functional cells, most readily observable in pigmented chimeras. These features suggest the possibility that Mes1 cells may be a fish equivalent of mouse ES cells and that medaka can be used as another system for the application of the ES cell technology.

Genetic restriction of AIDS pathogenesis by an SDF-1 chemokine gene variant. ALIVE Study, Hemophilia Growth and Development Study (HGDS), Multicenter AIDS Cohort Study (MACS), Multicenter Hemophilia Cohort Study (MHCS), San Francisco City Cohort (SFCC)

Stromal-derived factor (SDF-1) is the principal ligand for CXCR4, a coreceptor with CD4 for T lymphocyte cell line-tropic human immunodeficiency virus-type 1 (HIV-1). A common polymorphism, SDF1-3'A, was identified in an evolutionarily conserved segment of the 3' untranslated region of the SDF-1 structural gene transcript. In the homozygous state, SDF1-3'A/3'A delays the onset of acquired immunodeficiency syndrome (AIDS), according to a genetic association analysis of 2857 patients enrolled in five AIDS cohort studies. The recessive protective effect of SDF1-3'A was increasingly pronounced in individuals infected with HIV-1 for longer periods, was twice as strong as the dominant genetic restriction of AIDS conferred by CCR5 and CCR2 chemokine receptor variants in these populations, and was complementary with these mutations in delaying the onset of AIDS.

Incorporation of mouse neural progenitors transplanted into the rat embryonic forebrain is developmentally regulated and dependent on regional and adhesive properties

During development, telencephalic neural progenitors acquire positional specification and give rise to distinct structures such as the striatum and cortex. Here, we examine, in vivo, the influence of developmental stage, cell-surface molecules and regional differences along the dorso-ventral and antero-posterior axes on the selective incorporation of neural progenitors derived from different regions of the developing brain, utilizing a cross-species in utero transplantation paradigm. Striatal progenitors derived from the embryonic day (E) 12-14 mouse lateral ganglionic eminence (LGE) were observed consistently to incorporate into the developing striatum as early as 24-48 h following intraventricular injection into the E15-17 rat host. By removing cell-surface molecules from the LGE progenitors, the pattern of incorporation was remarkably different with no preferential striatal incorporation. Cortical progenitors with intact cell-surface molecules, by contrast, displayed little telencephalic (including striatal) incorporation as compared with precursors from the LGE. However, both progenitors from cortex and LGE incorporated widely into diencephalic and mesencephalic structures. The capacity for integration of precursors derived from the LGE and cortex gradually decreased during development of the host and was minimal in the postnatal day (P) 1 host. Unlike the telencephalic precursors, the vast majority of progenitors derived from the midbrain and cerebellar primordium (with cell-surface molecules intact) incorporated into diencephalic and midbrain nuclei with only a few cells observed in the telencephalon. These results demonstrate that incorporation of neural progenitors across the ventricular wall in the embryonic host is strictly developmentally regulated, dependent on their position along the antero-posterior axes and in the case of progenitors from the LGE is mediated by cell-surface molecules expressed on the transplanted cells.

Digital imagery/telecytology. International Academy of Cytology Task Force summary. Diagnostic Cytology Towards the 21st Century: An International Expert Conference and Tutorial

ISSUES

Optical digital imaging and its related technologies have applications in cytopathology that encompass training and education, image analysis, diagnosis, report documentation and archiving, and telecommunications. Telecytology involves the use of telecommunications to transmit cytology images for the purposes of diagnosis, consultation or education. This working paper provides a mainly informational overview of optical digital imaging and summarizes current technologic resources and applications and some of the ethical and legal implications of the use of these new technologies in cytopathology.

CONSENSUS POSITION

Computer hardware standards for optical digital imagery will continue to be driven mainly by commercial interests and nonmedical imperatives, but professional organizations can play a valuable role in developing recommendations or standards for digital image sampling, documentation, archiving, authenticity safeguards and teleconsultation protocols; in addressing patient confidentiality and ethical, legal and informed consent issues; and in providing support for quality assurance and standardization of digital image-based testing. There is some evidence that high levels of accuracy for telepathology diagnosis can be achieved using existing dynamic systems, which may also be applicable to telecytology consultation. Static systems for both telepathology and telecytology, which have the advantage of considerably lower cost, appear to have lower levels of accuracy. Laboratories that maintain digital image databases should adopt practices and protocols that ensure patient confidentiality. Individuals participating in telecommunication of digital images for diagnosis should be properly qualified, meet licensing requirements and use procedures that protect patient confidentiality. Such individuals should be cognizant of the limitations of the technology and employ quality assurance practices that ensure the validity and accuracy of each consultation. Even in an informal teleconsultation setting one should define the extent of participation and be mindful of potential malpractice liability.

ONGOING ISSUES

Digital imagery applications will continue to present new opportunities and challenges. Position papers such as this are directed toward assisting the profession to stay informed and in control of these applications in the laboratory. Telecytology is an area in particular need of studies of good quality to provide data on factors affecting accuracy. New technologic approaches to addressing the issue of selective sampling in static image consultation are needed. The use of artificial intelligence software as an adjunct to enhance the accuracy and reproducibility of cytologic diagnosis of digital images in routine and consultation settings deserves to be pursued. Other telecytology-related issues that require clarification and the adoption of workable guidelines include interstate licensure and protocols to define malpractice liability.

Studies on neuroprotective and regenerative effects of GDNF in a partial lesion model of Parkinson's disease

Intrastriatal 6-hydroxydopamine injections in rats induce partial lesions of the nigrostriatal dopamine (DA) system which are accompanied by a delayed and protracted degeneration of DA neurons within the substantia nigra. By careful selection of the dose and placement of the toxin it is possible to obtain reproducible and regionally defined partial lesions which are well correlated with stable functional deficits, not only in drug-induced behaviors but also in spontaneous motoric and sensorimotoric function, which are analogous to the symptoms seen in patients during early stages of Parkinson's disease. The intrastriatal partial lesion model has proved to be particularly useful for studies on the mechanisms of action of neurotrophic factors since it offers opportunities to investigate both protection of degenerating DA neurons during the acute phases after the lesion and stimulation of regeneration and functional recovery during the chronic phase of the postlesion period when a subset of the spared nigral DA neurons persist in an atrophic and dysfunctional state. In the in vivo experiments performed in this model glial cell line-derived neurotrophic factor (GDNF) has been shown to exert neurotrophic effects both at the level of the cell bodies in the substantia nigra and at the level of the axon terminals in the striatum. Intrastriatal administration of GDNF appears to be a particularly effective site for induction of axonal sprouting and regeneration accompanied by recovery of spontaneous sensorimotor behaviors in the chronically lesioned nigrostriatal dopamine system.

Phenotypic rescue of the albino mutation in the medakafish (Oryzias latipes) by a mouse tyrosinase transgene

Mutations of the tyrosinase gene are one common cause of a similar phenotype in all vertebrates, known as albinism. In an attempt to contribute to an understanding of the genetic hierarchy governing the development of pigmentation, we have used a mouse tyrosinase minigene under the control of its 5.2 kb upstream promoter region to rescue two different albino mutations in the medakafish, Oryzias latipes. Around hatching stages an almost perfect phenocopy of the wildtype pigmentation was obtained. Subsequent ectopic melanin overproduction indicated a possible incompatibility of the heterologous mouse promoter for stable expression during the entire ontogenesis. Like in some tyrosinase transgenic mouse lines a strong variegation effect was observed. The transgene-mediated pigmentation phenotype was obtained up to the eighth offspring generation. The phenotypic effects of the tyrosinase transgene in different albino mutant strains places the i3-locus upstream and the b-locus downstream of the tyrosinase locus i1 in the genetic hierarchy leading to wildtype pigmentation.

Generation and transplantation of EGF-responsive neural stem cells derived from GFAP-hNGF transgenic mice

EGF-responsive neural stem cells isolated from murine striatum have the capacity to differentiate into both neurons and glia in vitro. Genetic modification of these cells is hindered by a number of problems such as gene stability and transfection efficiency. To circumvent these problems we generated transgenic mice in which the human GFAP promoter directs the expression of human NGF. Neural stem cells isolated from the forebrain of these transgenic animals proliferate and form clusters, which appear identical to stem cells generated from control animals. Upon differentiation in vitro, the transgenic stem cell-derived astrocytes express and secrete bioactive hNGF. Undifferentiated GFAP-hNGF or control stem cells were transplanted into the striatum of adult rats. One and 3 weeks after transplantation, hNGF was detected immunocytochemically in an halo around the transplant sites. In GFAP-hNGF-grafted animals, intrinsic striatal neurons proximal to the graft appear to have taken up hNGF secreted by the grafted cells. Ipsilateral to implants of GFAP-hNGF-secreting cells, choline acetyltransferase-immunoreactive neurons within the striatum were hypertrophied relative to the contralateral side or control-grafted animals. Further, GFAP-hNGF-grafted rats displayed a robust sprouting of p75 neurotrophin receptor-positive fibers emanating from the underlying basal forebrain. These studies indicate that EGF-responsive stem cells which secrete hNGF under the direction of the GFAP promoter display in vitro and in vivo properties similar to that seen following other methods of NGF delivery and this source of cells may provide an excellent avenue for delivery of neurotrophins such as NGF to the central nervous system.

Grafts of EGF-responsive neural stem cells derived from GFAP-hNGF transgenic mice: trophic and tropic effects in a rodent model of Huntington's disease

The present study examined whether implants of epidermal growth factor (EGF)-responsive stems cells derived from transgenic mice in which the glial fibrillary acid protein (GFAP) promoter directs the expression of human nerve growth factor (hNGF) could prevent the degeneration of striatal neurons in a rodent model of Huntington's disease (HD). Rats received intrastriatal transplants of GFAP-hNGF stem cells or control stem cells followed 9 days later by an intrastriatal injection of quinolinic acid (QA). Nissl stains revealed large striatal lesions in rats receiving control grafts, which, on average, encompassed 12.78 mm3. The size of the lesion was significantly reduced (1.92 mm3) in rats receiving lesions and GFAP-hNGF transplants. Rats receiving QA lesions and GFAP-hNGF-secreting grafts stem cell grafts displayed a sparing of striatal neurons immunoreactive (ir) for glutamic acid decarboxylase, choline acetyltransferase, and neurons histochemically positive for nicotinamide adenosine diphosphate. Intrastriatal GFAP-hNGF-secreting implants also induced a robust sprouting of cholinergic fibers from subjacent basal forebrain neurons. The lesioned striatum in control-grafted animals displayed numerous p75 neurotrophin-ir (p75NTR) astrocytes, which enveloped host vasculature. In rats receiving GFAP-hNGF-secreting stem cell grafts, the astroglial staining pattern was absent. By using a mouse-specific probe, stem cells were identified in all animals. These data indicate that cellular delivery of hNGF by genetic modification of stem cells can prevent the degeneration of vulnerable striatal neural populations, including those destined to die in a rodent model of HD, and supports the emerging concept that this technology may be a valuable therapeutic strategy for patients suffering from this disease.

Evolutionary analysis of the 5'-terminal region of hepatitis G virus isolated from different regions in China

We have determined the nucleotide sequence of the 5'-terminal region of the hepatitis G virus (HGV) genome in 11 hepatitis patients from three cities in China. Phylogenetic analyses revealed that the Chinese isolates were genetically distinct from previously described West African isolates (type 1) and American, European and East African isolates (type 2), with a mean sequence divergence of approximately 10%. The mean divergence between isolates from Lanzhou, in the northwest of China, and those from Shanghai and Nanjing, on the east coast of China, was 5% (range 3-7%). The isolates from Shanghai and Nanjing were closely related to a common strain in Japan, while some of those from Lanzhou were closely related to a southeast Asian type 3 isolate. Thus, the Chinese isolates belong to the type 3 variant of HGV.

Eating disorders in adolescence in a Swiss epidemiological study

OBJECTIVE

This is a study of prevalence rates for anorexia nervosa (AN) and bulimia nervosa (BN) in an epidemiological sample of Swiss adolescents.

METHOD

A two-stage approach was used which involved the screening of a large sample of adolescents aged 14-17 and subsequent interviews of screen-positive and control subjects.

RESULTS

The prevalence rates for adolescent girls were 0.7% for AN and 0.5% for BN.

DISCUSSION

Full clinical syndromes of AN and BN in adolescents are by far less frequent than individual symptoms of eating disorders. There is more cross-cultural variation for prevalence rates in BN than in AN.

Radiotherapy in stage IIA and IIB testicular seminoma with reduced portals: a prospective multicenter study

PURPOSE

A prospective multicenter study was carried out to estimate the treatment outcome of radiotherapy in Stage II seminoma after the application of modern staging and radiotherapy techniques. The lower margin of the iliac field was positioned on the upper rim of the acetabulum to reduce the amount of scattered irradiation to the remaining testicle.

METHODS AND MATERIALS

The study was carried out in 25 centers in Germany. Patients with pure seminoma, negative AFP-values, and retroperitoneal lymph node metastases of less than 5 cm in diameter were entered into the study. All patients received a ventrodorsal opposed field irradiation of the para-aortic and the ipsilateral iliac lymph nodes. The fields extended from the top of the 11th thoracic vertebra to the top of the acetabulum. Patients in Stage IIA (lymph nodes <2 cm ) received 30 Gy, and patients with Stage IIB (lymph nodes between 2 and 5 cm) 36 Gy total dose.

RESULTS

39 patients in Stage IIA and 19 patients in Stage IIB were evaluated. After a median observation time of 37 months all patients are alive and disease free. Recurrence free survival in stage IIA was 100%. Two patients in Stage IIB experienced a recurrence 10 and 17 months after the end of radiotherapy. The actuarial recurrence free survival estimate in Stage IIB was 94.1% for 1 year and 87.4% for 2 years. One recurrence in Stage IIB occurred in the mediastinum, one in the mediastinum, and one the lung. Both patients could be salvaged by chemotherapy. There were no pelvic recurrences. The treatment was well tolerated, with nausea being the most common side effect (56.9% Grade 1, 15.5% Grade 2, and 8.6% Grade 3). Diarrhea occurred in 15.5% (Grade 1), 15.5% (Grade 2), and 5.2% (Grade 3) of the patients.

CONCLUSIONS

The outcome of para-aortic and ipsilateral iliac irradiation in Stage IIA/B testicular seminoma is excellent with the currently available staging methods and treatment facilities. The treatment is well tolerated. The lower margin of the iliacal field can be placed at the acetabulum.

Contrasting genetic influence of CCR2 and CCR5 variants on HIV-1 infection and disease progression. Hemophilia Growth and Development Study (HGDS), Multicenter AIDS Cohort Study (MACS), Multicenter Hemophilia Cohort Study (MHCS), San Francisco City Cohort (SFCC), ALIVE Study

The critical role of chemokine receptors (CCR5 and CXCR4) in human immunodeficiency virus-type 1 (HIV-1) infection and pathogenesis prompted a search for polymorphisms in other chemokine receptor genes that mediate HIV-1 disease progression. A mutation (CCR2-64I) within the first transmembrane region of the CCR2 chemokine and HIV-1 receptor gene is described that occurred at an allele frequency of 10 to 15 percent among Caucasians and African Americans. Genetic association analysis of five acquired immunodeficiency syndrome (AIDS) cohorts (3003 patients) revealed that although CCR2-64I exerts no influence on the incidence of HIV-1 infection, HIV-1-infected individuals carrying the CCR2-64I allele progressed to AIDS 2 to 4 years later than individuals homozygous for the common allele. Because CCR2-64I occurs invariably on a CCR5-+-bearing chromosomal haplotype, the independent effects of CCR5-Delta32 (which also delays AIDS onset) and CCR2-64I were determined. An estimated 38 to 45 percent of AIDS patients whose disease progresses rapidly (less than 3 years until onset of AIDS symptoms after HIV-1 exposure) can be attributed to their CCR2-+/+ or CCR5-+/+ genotype, whereas the survival of 28 to 29 percent of long-term survivors, who avoid AIDS for 16 years or more, can be explained by a mutant genotype for CCR2 or CCR5.

Activation of transcription of the melanoma inducing Xmrk oncogene by a GC box element

Melanoma formation in Xiphophorus is caused by overexpression of the Xmrk gene. The promoter region of the Xmrk oncogene differs strikingly from the corresponding proto-oncogenic sequences and was acquired in the course of a nonhomologous recombination with another gene locus, D. In order to identify regulatory elements leading to the strong transcriptional activation of Xmrk in melanoma tissue and to contribute to an understanding of the role the regulatory locus R might play in suppressing the tumor phenotype in wild-type Xiphophorus, we performed functional analysis of the Xmrk oncogene promoter. Transient transfections in melanoma and nonmelanoma cells revealed the existence of a potent positive regulatory element positioned close to the transcriptional start site. Contained within this promoter segment is a GC-rich sequence identical to the binding site described for human Sp1. In vitro binding studies and biochemical characterizations demonstrated the existence of GC-binding proteins in fish that share immunological properties with members of the human Sp family of transcription factors and appear to be involved in the high transcriptional activation of the Xmrk oncogene. Since the identified cis element is functional in both melanoma and nonmelanoma cells, additional silencer elements suppressing Xmrk expression in nonpigment cells must exist, thereby suggesting a negative regulatory function for the genetically defined R locus.

[Frozen section diagnosis using telepathology]

DEFINITION

Since 1992 we transfer digitalized frozen section images by means of videomicroscope and a personal computer through the public telephone network (ISDN) to the Institut of Pathology at the University Hospital in Basel. The aim of this study is to determine whether the quality of frozen section diagnosis obtained by telepathology is comparable to the conventional one.

METHOD

The frozen section diagnoses by telepathology from Oct. 1992 to May 1996 (n = 94) are compared to the paraffin sections performed in each case after the primary examination. The result is then compared to the well documented data of conventional frozen section diagnosis in the literature.

RESULTS

From Oct. 1992 to May 1996 we performed 94 frozen sections. In 84 cases the diagnosis was correct compared to the paraffin section (89%). The sensitivity to detect a malignant tumor was 92%, the specifity 100%. Four examinations were not conclusive and one examination had to be canceled because of technical problems.

DISCUSSION

In the literature, 92% of malignancy is diagnosed by conventional frozen section [1]. Telepathology gives the same result.

Who should be screened to reduce the endoscopy workload in Mulago Hospital?

A retrospective study of 330 patients who had been endoscoped in Mulago hospital was done. It was found that of these 119 (36.1%) were normal endoscopically. Normal endoscopy was significantly associated with patients presenting with dyspepsia. Dyspepsia was commoner in the age group 13-45 years compared to the age group 46-85 years. The older age group, 46-85 years, had a significantly higher prevalence of serious disease. It is concluded that it is the younger patients with dyspepsia who should be screened to reduce the endoscopy workload. Published guidelines should be used to assist in the screening process.

[The efficacy of radiotherapy in vertebral hemangiomas]

AIM

Assessment of the efficacy of radiation therapy for symptomatic vertebral hemangiomas.

PATIENTS AND METHODS

Records of 19 patients who were treated from 1969 to 1988 were retrospectively analyzed. Radiation treatment was given at 2 Gy per fraction to 20 Gy (n = 2), 30 Gy (n = 11), or 40 Gy (n = 6). Improvement of symptoms was chosen to determine the efficacy of the treatment. In addition the lesions were controlled radiographically.

RESULTS

Symptomatic improvement was achieved in 17 of 19 patients, remission was complete in 7 patients. No dose-response relationship was observed. The median time to improvement of symptoms was 3 months. The radiographic controls did not correlate with the clinical course.

CONCLUSIONS

Radiation therapy is an effective treatment for symptomatic vertebral hemangiomas. The aim of the treatment is to ameliorate clinical symptoms, radiographic improvement is of minor importance.

Short-term GDNF treatment provides long-term rescue of lesioned nigral dopaminergic neurons in a rat model of Parkinson's disease

Glial cell line-derived neurotrophic factor (GDNF) has been shown to exert neuroprotective effects on dopamine (DA) neurons in vivo. Here we report long-term rescue of nigral DA neurons after delayed short-term GDNF administration in a rat lesion model that reproduces the slowly progressing degenerative process seen in Parkinson's disease. GDNF injected close to the substantia nigra provided near-complete protection and persistent survival of the lesioned nigral neurons for at least 4 months after discontinuation of GDNF treatment. Long-term rescue of the nigral cells, however, was not accompanied by any significant reinnervation of the lesioned striatal target or any signs of functional recovery in either drug-induced or spontaneous motor behaviors. We conclude that not only preservation of the nigral DA neurons but also restoration of striatal DA function is necessary for functional recovery in the rat Parkinson model.

Pluripotency and differentiation of embryonic stem cell lines from the medakafish (Oryzias latipes)

Small aquarium fish, like the medaka and zebrafish, offer an excellent opportunity to combine embryological, genetic and molecular analyses of vertebrate development. Pluripotent embryonic stem (ES) cells have enormous potential to study the totipotency and differentiation of cells and provide s bridge linking in vitro manipulations of the genome. In this report we describe the establishment, pluripotency and differentiation of medaka ES-like cell lines (MES). The MES cells exhibit stable growth over 18 months of culture with 100 passages using defined culture conditions in the absence of feeder layer cells. They have a normal karyotype and form colonies of densely packed, alkaline phosphatase-positive cells resembling undifferentiated mouse ES cells. In suspension culture they form embryoid bodies, and under appropriate conditions, differentiate into a variety of cell types.

Genetic restriction of HIV-1 infection and progression to AIDS by a deletion allele of the CKR5 structural gene. Hemophilia Growth and Development Study, Multicenter AIDS Cohort Study, Multicenter Hemophilia Cohort Study, San Francisco City Cohort, ALIVE Study

The chemokine receptor 5 (CKR5) protein serves as a secondary receptor on CD4(+) T lymphocytes for certain strains of human immunodeficiency virus-type 1 (HIV-1). The CKR5 structural gene was mapped to human chromosome 3p21, and a 32-base pair deletion allele (CKR5Delta32) was identified that is present at a frequency of approximately0.10 in the Caucasian population of the United States. An examination of 1955 patients included among six well-characterized acquired immunodeficiency syndrome (AIDS) cohort studies revealed that 17 deletion homozygotes occurred exclusively among 612 exposed HIV-1 antibody-negative individuals (2.8 percent) and not at all in 1343 HIV-1-infected individuals. The frequency of CKR5 deletion heterozygotes was significantly elevated in groups of individuals that had survived HIV-1 infection for more than 10 years, and, in some risk groups, twice as frequent as their occurrence in rapid progressors to AIDS. Survival analysis clearly shows that disease progression is slower in CKR5 deletion heterozygotes than in individuals homozygous for the normal CKR5 gene. The CKR5Delta32 deletion may act as a recessive restriction gene against HIV-1 infection and may exert a dominant phenotype of delaying progression to AIDS among infected individuals.

Intraoperative autotransfusion in aortic surgery: comparison of whole blood autotransfusion versus cell separation

OBJECTIVE

Differences concerning alteration of hemostatic, hemolysis, and hematologic parameters after transfusion of blood from a cell-separation (CS) device or whole blood autotransfusion (WBA) were prospectively evaluated during major aortic surgery.

METHOD

Thirty-two patients were randomly selected to receive autologous retransfusion by using either WBA or a CS device. Coagulation and hematologic parameters and levels of hemolytic degradation products (HDP) were assessed in the retransfused blood and in the patients' plasma preoperatively and until 24 hours after autologous retransfusion, respectively.

RESULTS

Mean volume of retransfused blood was 1072 +/- 473 ml in the WBA group and 556 +/- 504 in the CS group. Level of HDP (bilirubin, free hemoglobin [free HB], and lactic dehydrogenase [LDH] and hemostatic disturbances (d-dimer value, fibrin degradation products) were significantly higher in the WBA device compared with the CS blood. Blood samples taken from the WBA group revealed significantly higher level of HDP (free HB, LDH) and of d-dimer values after autotransfusion compared with the CS group.

CONCLUSION

Levels of HDP and the degree of hemostatic disturbances were significantly higher in retransfused whole blood compared with CS blood. Hemostatic disturbances and levels of HDP were significantly pronounced in the patients' plasma after WBA compared with CS. CS retransfused blood seems to be of superior quality compared with WBA and the degree of hemolysis and hemostatic disturbances is minor after CS retransfusion.

Influence of combinations of human major histocompatibility complex genes on the course of HIV-1 infection

Major histocompatibility complex (MHC) genes (HLA in humans) regulate the immune response to foreign antigens. Molecular and serologic techniques were used to identify products of HLA class I, class II and transporter (TAP) genes (also part of the MHC) in homosexual seroconverters to human immunodeficiency virus type 1 (HIV-1). Comprehensive statistical analysis produced an HLA profile that predicted time from HIV-1 infection to the onset of AIDS. The profile was developed in a cohort of 139 men and evaluated in a second unrelated cohort of 102 men. In the evaluation cohort, the profile discriminated a sixfold difference between groups with the shortest and longest times to AIDS (P = 0.001). These findings support current theory about control of antigen processing by HLA genes and have implications for immunopathogenesis of HIV-1 and other infections.

Conditionally immortalized neural progenitor cells grafted to the striatum exhibit site-specific neuronal differentiation and establish connections with the host globus pallidus

The cell line RN33B has been reported to differentiate into neurons in a site-specific manner when grafted to the cortex and hippocampus of adult rats. To investigate the fate of RN33B cells in a subcortical structure, we grafted RN33B cells into the intact or excitoxically lesioned striatum of adult or neonatal rats. The total number and phenotypic characteristics of the [3H]thymidine-labeled grafted cells were analyzed at different time points after transplantation. Transplanted RN33B cells were found to survive, integrate, and differentiate into both neurons and astrocytes, and a significant proportion of the cells (approx. 10%) were found to differentiate into cells with morphological and phenotypic characteristics of medium-sized striatal projection neurons. Retrograde tracing showed that at least some of the graft-derived neurons were capable of establishing connections with one of the primary striatal targets, the globus pallidus. These findings demonstrate a remarkable capacity of the RN33B cells for site-specific neuronal differentiation in both the adult and the developing striatum and suggest that the same differentiating factors that are operating during normal neurogenesis in brain development are retained, at least to some extent, also in the adult CNS.