Loss of heterozygosity and microsatellite instability in de novo versus ex-adenoma carcinomas of the colorectum

Small adenocarcinomas of the colorectum showing no evidence of origin from an adenoma have been called de novo carcinomas, a name that implies an origin via a different molecular genetic mechanism than the usual colorectal carcinoma which develops from an adenoma. Using microsatellite analysis, 35 early (pT1) de novo and 36 pT1 ex-adenoma carcinomas were compared using 8 microsatellite loci at 6 different chromosomal loci (1p, 2p, 8p, 5q, 17p, and 18q) known or hypothesized to be important for colorectal carcinogenesis. The rate of loss of heterozygosity (LOH) at the 17p locus (near the p53 gene) was significantly higher in the de novo than in the ex-adenoma group (73 vs. 37%, P = 0.004). The rates of LOH at the other loci (including the APC and DCC genes) and the rate of MSI were not significantly different in the two groups. These results indicate that de novo carcinomas of the colorectum develop via a similar carcinogenetic pathway as conventional ex-adenoma carcinomas; however, their higher rate of LOH at 17p is evidence for a biologically more advanced lesion with more frequent p53 mutations, consistent with clinicopathological data indicating that de novo carcinomas are more aggressive than ex-adenoma carcinomas.

CDKN2a/p16INK4a mutations and lack of p19ARF involvement in familial melanoma kindreds

Germline mutations in the cyclin-dependent kinase inhibitor 2a (CDKN2a) gene, which maps to the 9p21 chromosomal region and encodes the cyclin-dependent kinase inhibitor p16INK4a, have been detected in a proportion of familial melanoma kindreds, suggesting that it is the putative 9p21-linked melanoma susceptibility gene. The p19ARF transcript, an alternative spliced form of the CDKN2a gene, has recently been shown to inhibit, like the p16INK4a protein, cell cycle progression, raising the possibility that it might constitute an additional melanoma tumor suppressor gene at the 9p21 locus. To determine the contribution of these candidate genes to familial melanoma genetic predisposition, we screened 10 such kindreds for germline mutations in the p16INK4a and p19ARF genes. Four independent germline missense mutations, mapping in exon 1alpha (Gly23Asp; Arg24Pro) and exon 2 (Asn71Ileu; Pro114Leu) of the CDKN2a gene, were identified. Two previously described polymorphisms were also detected, Ala148Thr in exon 2 and a base change in the 3' untranslated region of exon 3. No disease-associated mutations in exon 1beta of the p19ARF gene were found. Our data support the hypothesis that the CDKN2a is a melanoma susceptibility gene in familial melanoma, whereas the p19ARF gene does not seem to play a significant role.

Identification of a fetal hematopoietic precursor with B cell, T cell, and macrophage potential

Despite years of investigation, precursor-progeny relationships within the developing lymphoid lineages of the hematopoietic system remain poorly defined. We have characterized the potential of precursors found within a subpopulation of fetal liver defined by AA4.1 and Fc gammaRII/III expression and predominantly restricted to lymphoid and macrophage development. When cultured in methylcellulose with appropriate cytokines, AA4.1+/Fc gammaR+ precursors generate colonies consisting of various lineages, including the combination of B cell, T cell, and macrophage. Retroviral marking studies showed that the lymphoid cells and macrophages within these colonies arise from a common precursor. These results demonstrate the presence of a common precursor with B cell-, T cell-, and macrophage-restricted potential and as such define an early restriction point within the fetal lymphoid system.

The beta-globin LCR is not necessary for an open chromatin structure or developmentally regulated transcription of the native mouse beta-globin locus

The murine beta-globin locus control region (LCR) was deleted from its native chromosomal location. The approximately 25 kb deletion eliminates all sequences and structures homologous to those defined as the human LCR. In differentiated ES cells and erythroleukemia cells containing the LCR-deleted chromosome, DNasel sensitivity of the beta-globin domain is established and maintained, developmental regulation of the locus is intact, and beta-like globin RNA levels are reduced 5%-25% of normal. Thus, in the native murine beta-globin locus, the LCR is necessary for normal levels of transcription, but other elements are sufficient to establish the open chromatin structure, transcription, and developmental specificity of the locus. These findings suggest a contributory rather than dominant function for the LCR in its native location.

Overexpression of HOX11 leads to the immortalization of embryonic precursors with both primitive and definitive hematopoietic potential

Primitive and definitive erythropoiesis represent distinct hematopoietic programs that differ with respect to stage of development, transcriptional control, and growth regulation. Although these differences have been recognized for some time, the relationship of the two erythroid lineages to each other is not well established. We have used a model system based on the hematopoietic development of embryonic stem (ES) cells in culture to investigate the origins of the earliest hematopoietic populations. Using ES cells transduced with a retrovirus that overexpresses the HOX11 gene, we have established factor-dependent hematopoietic cell lines that represent novel stages of embryonic hematopoiesis. Analysis of three of these cell lines indicates that they differ with respect to cytokine responsiveness, cell surface markers, and developmental potential. Two of the cell lines, EBHX1 and EBHX11, display the unique capacity to generate both primitive and definitive erythroid progeny as defined by morphology and expression of betaH1 and betamajor globin. The third line, EBHX14, has definitive erythroid and myeloid potential, but is unable to generate cells of the primitive erythroid lineage. Analysis of the cytokine responsiveness of the two lines with primitive erythroid potential has indicated that exposure to leukemia inhibitory factor (LIF) results in the upregulation of betaH1 and a change in cellular morphology to that of primitive erythrocytes. These findings are the first demonstration of a clonal cell line with primitive and definitive hematopoietic potential and support the interpretation that these lineages may arise from a common precursor in embryonic life. In addition, they suggest that LIF could play a role in the regulation of primitive erythropoiesis.

Microsatellite instability and loss of heterozygosity in gastric carcinoma in comparison to family history

We compared 29 gastric carcinomas from patients with a variably strong family history for gastric cancer (group 1) with 36 gastric carcinomas from patients without a family history of this disease (group 2) for microsatellite instability (MSI) and loss of heterozygosity (LOH) with 12 microsatellite markers. Both study groups had similar proportions of histological types and tumor locations. Widespread MSI (alterations at > or = 6 loci) was seen in 5 of 29 (17%) of the tumors belonging to group 1 and in 4 of 36 (11%) group 2 tumors. MSI at a low level (alterations at 1 to 3 loci) was observed in 12 of 29 (41%) of tumors in group 1 and in 10 of 36 (28%) of tumors in group 2, differences that were not statistically significant. A significant difference with respect to low level MSI was observed between the two groups when considering the overall mutation rate of microsatellites. Seventeen of 281 (6%) analyzed microsatellite loci showed alterations in group 1 and 11 of 381 (2.9%) in group 2 (P = 0.046). Comparison of both types of MSI to the clinicopathological parameters in both groups revealed a significant association of low level MSI with advanced tumor stages (P = 0.046) in the group 2, whereas no such association was observed in group 1. In respect to LOH, a significant difference between the two groups was observed at chromosome 17p12, as 13 of 22 (59%) informative cases of group 1 showed LOH in comparison with 7 of 26 (27%) (P = 0.024) in group 2. No correlation of LOH at chromosome 17p12 to the pathological or clinical data was observed either in the two groups or in the study as a whole. Our data show that gastric carcinomas of patients with a positive family history of gastric cancer in group 1 are characterized by a higher mutation rate in respect to low level MSI, particularly at dinucleotide repeats, and by a higher frequency of LOH at chromosome 17p12, indicating that different genetic pathways are involved in the pathogenesis of gastric carcinomas arising in patients with and without a familial background of this disease.

A common precursor for hematopoietic and endothelial cells

Embryonic stem cell-derived embryoid bodies contain a unique precursor population which, in response to vascular endothelial growth factor, gives rise to blast colonies in semi-solid medium. Upon transfer to liquid culture with appropriate cytokines, these blast colonies generate both hematopoietic and adherent, stromal-type cells. Cells within the adherent population display characteristics of endothelial lineage including the expression of CD31, flk-1, flt-1, tie-2, the capacity to take up acetylated LDL and the presence of cytoplasmic Weibel-Palade bodies. Mixing studies demonstrated that the hematopoietic and endothelial precursors within the blast colonies develop from the same cell, the blast colony-forming cell. Kinetic analysis showed that the blast colony-forming cell represents a transient cell population that develops early and is lost quickly during embryoid body development. These findings provide strong evidence that the blast colony-forming cell represents the long-hypothesized hemangioblast, the common precursor of the hematopoietic and endothelial lineages.

Frequent loss of heterozygosity at chromosome 13q12-13 with BRCA2 markers in sporadic male breast cancer

Molecular genetic analysis indicates that the BRCA2 gene plays an important role in familial male breast cancer. To determine a possible involvement of this tumor suppressor gene in sporadic male breast cancer, we examined 30 sporadic male breast carcinomas for loss of heterozygosity (LOH) at two loci on chromosome 13q12-13, a region that spans the BRCA2 locus. Sixteen of 24 (67%) informative cases showed LOH in at least one marker on chromosome 13q12-13. The affected cases included both invasive ductal carcinomas and other types of invasive breast carcinoma and were detected preferentially in patients who were 50 years or older, in patients with lymph node metastasis, and in progesterone receptor-negative cases. We report, for the first time, a high frequency of LOH at chromosome 13q12-13 in sporadic male breast cancer and its association with factors indicating a poor prognosis for this tumor (e.g., lymph node metastasis and negative progesterone receptor status). These findings suggest an important role for BRCA2 in the development and progression of sporadic male breast cancer.

Multilineage engraftment in NOD/LtSz-scid/scid mice from mobilized human CD34+ peripheral blood progenitor cells

Peripheral blood progenitor cells (PBPCs) are now the most widely used source for hematopoietic support of patients in the autologous transplant setting and are increasingly being used for allogeneic transplantation. A reliable model to characterize the in vivo potential of various PBPC subpopulations could be valuable as a preclinical assay to predict the hematopoietic performance in humans of these populations and of products resulting from their manipulations ex vivo. We have used immunocompromised nonobese diabetic/LtSz-scid/scid (NOD/SCID) mice to engraft human CD34+ PBPCs and to study the repopulation characteristics of this progenitor cell fraction. Following myeloablation, intravenous infusion of CD34+ cells consistently produced engraftment and development in mice. Multilineage development occurred in all mice with CD34+ cells, erythroid precursors, and the most immature populations of myeloid cells and B lymphocytes restricted to the mouse bone marrow (BM). More mature populations of myeloid cells and B lymphocytes were peripheralized to the spleen and blood of the animals. This finding suggests that human hematopoiesis in the mice may recapitulate hematopoietic recovery in humans. The provision of human growth factors was not necessary for either engraftment or development of CD34+ cells. When mice were supplemented with growth factors, engraftment levels were unaffected but development was biased toward myeloid production. These findings indicate that providing nonphysiological levels of human growth factors may obscure or enhance the developmental potential of particular progenitor cell populations in this model. Cells capable of initiating colony formation in vitro were maintained in BM during the engraftment period (up to 17 weeks), suggesting that continuous production of myeloid and erythroid precursors occurred from more primitive hematopoietic cells subsequent to engraftment. In comparing results from this study with previous results, it was found that in this model the engraftment potential of CD34+ umbilical cord blood cells is greater than that described here for CD34+ PBPCs. In summary, this model may provide a reliable assay to predict the hematopoietic potential of progenitor cell populations in humans if a correlation for engraftment of identical cell fractions can be established between the two species.

Identification of allelic losses in benign, borderline, and invasive epithelial ovarian tumors and correlation with clinical outcome

BACKGROUND

The somatogenetic alterations that lead to the development of benign adenomas, borderline tumors, and invasive ovarian carcinomas are not well understood. This study investigated allelic losses in these three types of ovarian tumors.

METHODS

Twelve genetic regions on chromosomes 2q, 5q, 6p, 6q, 9p, 11q, 17p, 17q, 18q, and 22q were analyzed by polymerase chain reaction for loss of heterozygosity (LOH). The study was performed on formalin fixed, paraffin embedded tissue samples from 72 invasive ovarian carcinomas, 35 ovarian tumors of borderline malignancy, and 25 benign ovarian adenomas.

RESULTS

LOH was found in only 8% of the analyzed adenomas (at 2q21 and 17p13) and 11% of the borderline tumors (at 2q21, 5q21, 6p21, 17p13, and 17q21). Allelic losses were noted for 77.7% of all of the invasive carcinomas analyzed. The frequency of LOH was 56% at a locus near 17p13 (TP53) and 40.5% at 17q21 (BRCA1). LOH was observed in 30.4% of informative cases at 5q21 and in 21.4% at chromosome 18q21. The chromosomal regions 2q21-22 and 9p21 had deletions at frequencies of 32.4% and 25%, respectively. International Federation of Gynecology and Obstetrics stage and the presence of LOH correlated significantly with survival but were not independent predictors of survival. Serous subtypes of invasive carcinoma were significantly more prone to deletions than nonserous tumors.

CONCLUSIONS

The results of this study suggest that LOH occurs only occasionally in adenomas and borderline tumors, whereas it is frequently observed in invasive ovarian carcinomas. Therefore, other genetic events seem to be involved in early ovarian tumor development. However, the presence of multiple allelic losses is an indicator of higher stages of invasive carcinoma.

Widespread microsatellite instability in sebaceous tumours of patients with the Muir-Torre syndrome

Muir-Torre syndrome (MTS) is an autosomal dominant disorder characterized by the presence of at least one sebaceous gland tumour and a minimum of one visceral malignant tumour. Recently, microsatellite instability (MSI) has been detected in the tumours of patients with MTS and germline mutations of the hMSH2 and hMLH1 mismatch repair genes have been detected in some patients with this syndrome. To determine if the tumours of patients with MTS have widespread genomic instability and whether loss of heterozygosity (LOH) in the chromosomal regions containing hMSH2 and hMLH1 is detectable, MSI and LOH were examined at 10 dinucleotide repeats on chromosomes 2p, 3p, 5q, 9p, 17p and 18q. Data were obtained from six sebaceous gland tumours and two adenocarcinomas of the colon from three patients of two Muir-Torre families. MSI was detected at more than half of the loci tested in all sebaceous tumours examined. In addition, there was LOH at D2S119 in one sebaceoma and one sebaceous carcinoma from one patient. The colon carcinomas from two patients showed MSI at five of the 10 loci analysed. These results show that widespread MSI is a feature of tumours in patients with MTS. In addition, the finding of LOH at D2S119, a marker located in the vicinity of hMSH2, in sebaceous tumours of one patient indicates that this gene may have a pathogenetic role in this patient.

The CCK-B agonist, BC264, increases dopamine in the nucleus accumbens and facilitates motivation and attention after intraperitoneal injection in rats

Although it is known that panic attacks are triggered by the cholecystokinin fragment CCK4, the specific involvement of peripheral or central cholecystokinin CCK receptors in various adaptive processes such as emotion, memory and anxiety has yet to be demonstrated. With this aim, we have investigated the biochemical and pharmacological effects resulting from the administration of BC264, a highly potent and selective CCK-B agonist able to cross the blood-brain barrier. Very low doses of BC264 (microg/kg i.p.), increased the exploration of animals submitted to an unknown territory but were devoid of anxiogenic properties in the elevated plus maze. BC264 increased locomotion and rearings of rats newly placed in an open field and improved their spontaneous alternation in a Y-maze. The use of vagotomized animals showed that the increased alternation induced by BC264 did not require an intact vagus nerve, unlike the locomotor activation. These behavioural effects, prevented by the prior i.p. administration of the CCK-B antagonist L-365,260 but not by the CCK-A antagonist L-364,718, were shown to depend on dopaminergic systems, since they were blocked by D1 (SCH23390, 25 microg/kg i.p.) or D2 (sulpiride, 50 or 100 mg/kg i.p.) antagonists. In addition, bilateral perfusion in freely moving rats of BC264 at pharmacologically active doses, using a newly designed microdialysis system, was found to increase the extracellular levels of DA, DOPAC and HVA in the anterior part of the nucleus accumbens. These results show that activation of CCK-B receptors by BC264 does not produce anxiogenic-like effects but appears to improve motivation and attention, whereas other CCK-B agonists such as BocCCK4 induce anxiogenic responses. Several explanations, including the existence of different sub-sites of the CCK-B receptor, could account for these differential effects.

Engraftment and development of human CD34(+)-enriched cells from umbilical cord blood in NOD/LtSz-scid/scid mice

Understanding the repopulating characteristics of human hematopoietic stem/progenitor cell fractions is crucial for predicting their performance after transplant into high-risk patients following high-dose therapy. We report that human umbilical cord blood cells, 78% to 100% of which express the hematopoietic progenitor cell surface marker CD34, can consistently engraft, develop, and proliferate in the hematopoietic tissues of sublethally irradiated NOD/LtSz-scid/scid mice. Engraftment and development of CD34+ cells is not dependent on human growth factor support. CD34+ cells home to the mouse bone marrow (BM) that becomes the primary site of human hematopoietic development containing myeloid, lymphoid, erythroid, and CD34+ progenitor populations. Myeloid, and in particular lymphoid cells possessing more mature cell surface markers, comprise the human component of mouse spleen and peripheral blood, indicating that development proceeds from primary hematopoietic sites to the periphery. Repopulation of secondary recipients with human cells by BM from primary recipients demonstrates the maintenance of substantial proliferation capacity of the input precursor population. These data suggest that the cells capable of initiating human cell engraftment (SCID-repopulating cells) are contained in the CD34+ cell fraction, and that this mouse model will be useful for assaying the developmental potential of other rare human hematopoietic cell fractions in vivo.

Flk-1 expression defines a population of early embryonic hematopoietic precursors

We have investigated the expression pattern of the Flk-1 receptor tyrosine kinase in mouse embryonic and fetal hematopoietic tissues as well as on hematopoietic precursor cells derived from these tissues. RNA analysis indicated that flk-1 was expressed in the yolk sac at day 10 of gestation, in the whole embryo at day 10 and 12 of gestation, in the liver throughout fetal life and in embryoid bodies (EBs) generated from ES cells differentiated in culture. Flk-1 message was also detected in erythroid and macrophage colonies generated from precursors of yolk sac, fetal liver, adult marrow and EB origin. Using an antibody directed against the extracellular portion of the molecule we have found that up to 50% of cells from EBs differentiated for 4 days express Flk-1. Following the development of this early Flk-1+ population the number of receptor-positive cells declines progressively to represent less than 5% of the EBs by day 12 of differentiation. Kinetic analysis revealed that the establishment of the EB Flk-1+ population precedes the development of cells which express CD34, Ly6A (Sca-1) and AA4.1. Cell sorting experiments demonstrated that all day-4 EB-derived hematopoietic precursors are Flk-1+ whereas greater than 95% of those found within the day-12 EBs are Flk-1-, suggesting that the precursor population which expresses this receptor represents an early but transient wave of hematopoietic development. Analysis of yolk sac and whole embryos at day 8.5 of gestation revealed a small but distinct Flk-1+ population that contained hematopoietic precursors. Day-12.5 fetal liver contained few Flk-1+ cells that showed little hematopoietic potential. Together these findings indicate that Flk-1 is expressed on an early population of hematopoietic precursors that may represent the onset of embryonic hematopoiesis.

A common precursor for primitive erythropoiesis and definitive haematopoiesis

The generation of blood cells, haematopoiesis, in the mouse embryo begins with the development of primitive nucleated erythroid cells in the yolk sac followed by the appearance of precursors for multiple definitive haematopoietic lineages. The later developing lineages arise from multipotential stem cells, but the relationship of primitive erythroid cells to these other haematopoietic populations is unknown. Using an in vitro embryonic stem (ES) cell differentiation system, we show that primitive erythrocytes and other haematopoietic lineages arise from a common multipotential precursor that develops within embryoid bodies generated from differentiated ES cells. In response to vascular endothelial growth factor and c-kit ligand these precursors give rise to colonies containing immature cells (blasts) expressing marker genes characteristic of haematopoietic precursors. Many blast colonies also expressed betaH1 and beta major globins but not Brachyury, a mesodermal marker. Kinetic analysis demonstrated that the blast colony-forming cells represent a transient population, preceding the establishment of the primitive erythroid and other lineage-restricted precursors. This precursor population may represent the earliest stage of embryonic haematopoietic commitment.

Leptin stimulates fetal and adult erythroid and myeloid development

The ob gene product, leptin, has been shown in several studies to be involved in weight control and recombinant leptin recently has entered clinical trials to treat obesity. The leptin receptor (OB-R/B219) is expressed in a variety of protein isoforms not only in the central nervous system, but also in reproductive, and hematopoietic tissues. We reported recently that the OB-R/B219 was associated with a variety of hematopoietic lineages as well as the small fraction of cells containing the long-term reconstituting hematopoietic stem cells. Herein we report that leptin significantly stimulates the proliferation and differentiation of yolk sac cells and fetal liver cells and stimulates directly hematopoietic precursors. Leptin alone can increase the number of macrophage and granulocyte colonies, and leptin plus erythropoietin act synergistically to increase erythroid development. These data show that leptin has a significant, direct effect on early hematopoietic development and can stimulate the differentiation of lineage-restricted precursors of the erythrocytic and myelopoietic lineages. These observations along with a recent report strongly support our previous hypothesis that leptin has an unanticipated important role in hematopoietic and immune system development.

Analysis of microsatellite instability and loss of heterozygosity in keratoacanthoma

We analyzed microsatellite instability (MSI) and loss of heterozygosity (LOH) at 17 microsatellite markers located on chromosomes 2p, 3p, 5q, 6q, 9p, 9q, 17p and 18q in 19 randomly selected keratoacantomas (KAS), in one cutaneous lesion that histologically could not unequivocally be differentiated from squamous cell carcinoma, and in one patient with multiple KAs of longstanding duration. The goals of our study were to determine whether, in a similar manner to some visceral carcinomas, genomic instability could be detected in KAs and to clarify whether molecular analysis might be useful to further characterize KA. MSI was observed in 2 of 21 cases (9.5%) at 5 of 17 loci examined. In one patient with a solitary KA, the presence of MSI and a family history of visceral malignant tumours suggested that the patient might have belonged to a family with Muir-Torre syndrome. In one other MSI+ KA, a definite differential diagnosis in relation to squamous cell carcinoma could not be established. In addition, one sample displayed LOH at 2 of 17 loci analysed whereas in the patient with multiple KAs, LOH at one locus was the only alteration found. In conclusion, the low frequency of MSI and LOH detected in our study suggests that these genetic events are uncommon in KA unless it is associated with a familial disease (e.g. Muir-Torre syndrome) or it has more aggressive histological features.

Analysis for microsatellite instability and mutations of the DNA mismatch repair gene hMLH1 in familial gastric cancer

We examined 30 gastric-cancer patients with a varying degree of family history of stomach cancer and/or synchronous gastric tumors for microsatellite instability. We observed microsatellite instability at at least 1 of 8 loci tested in tumors of 14/30 patients; of these 14, 8 had single locus alterations and 6 had alterations at at least half of the 8 loci. Among the patients with microsatellite instability at > or = 4 loci, 3 patients showed a strong familial clustering of gastric cancer. Mutation analysis of the DNA mismatch repair gene hMLHl on paired non-tumorous and tumor DNA from 10 patients, 6 with microsatellite instability at > or = 4 loci and 4 with an alteration at one locus, revealed a novel missense mutation, present in the normal and tumor DNA of one patient with microsatellite instability at multiple loci in his tumor. His family history of cancer included one second-degree relative affected with gastric cancer. These data suggest that germline mutations in the hMLHl gene occur in some gastric-cancer patients and that in the majority of cases microsatellite instability in gastric tumors may be due to defects in other genes responsible for DNA replication fidelity than the hMLHl.

Analysis for microsatellite instability and mutations of the DNA mismatch repair gene hMLH1 in familial gastric cancer

We examined 30 gastric-cancer patients with a varying degree of family history of stomach cancer and/or synchronous gastric tumors for microsatellite instability. We observed microsatellite instability at at least 1 of 8 loci tested in tumors of 14/30 patients; of these 14, 8 had single locus alterations and 6 had alterations at at least half of the 8 loci. Among the patients with microsatellite instability at > or = 4 loci, 3 patients showed a strong familial clustering of gastric cancer. Mutation analysis of the DNA mismatch repair gene hMLHl on paired non-tumorous and tumor DNA from 10 patients, 6 with microsatellite instability at > or = 4 loci and 4 with an alteration at one locus, revealed a novel missense mutation, present in the normal and tumor DNA of one patient with microsatellite instability at multiple loci in his tumor. His family history of cancer included one second-degree relative affected with gastric cancer. These data suggest that germline mutations in the hMLHl gene occur in some gastric-cancer patients and that in the majority of cases microsatellite instability in gastric tumors may be due to defects in other genes responsible for DNA replication fidelity than the hMLHl.

Metabolic pathway engineering in cotton: biosynthesis of polyhydroxybutyrate in fiber cells

Alcaligenes eutrophus genes encoding the enzymes, beta-ketothiolase (phaA), acetoacetyl-CoA reductase (phaB), and polyhydroxyalkanoate synthase (phaC) catalyze the production of aliphatic polyester poly-d-(-)-3-hydroxybutyrate (PHB) from acetyl-CoA. PHB is a thermoplastic polymer that may modify fiber properties when synthesized in cotton. Endogenous beta-ketothiolase activity is present in cotton fibers. Hence cotton was transformed with engineered phaB and phaC genes by particle bombardment, and transgenic plants were selected based on marker gene, beta-glucuronidase (GUS), expression. Fibers of 10 transgenic plants expressed phaB gene, while eight plants expressed both phaB and phaC genes. Electron microscopy examination of fibers expressing both genes indicated the presence of electron-lucent granules in the cytoplasm. High pressure liquid chromatography, gas chromatography, and mass spectrometry evidence suggested that the new polymer produced in transgenic fibers is PHB. Sixty-six percent of the PHB in fibers is in the molecular mass range of 0.6 x 10(6) to 1.8 x 10(6) Da. The presence of PHB granules in transgenic fibers resulted in measurable changes of thermal properties. The fibers exhibited better insulating characteristics. The rate of heat uptake and cooling was slower in transgenic fibers, resulting in higher heat capacity. These data show that metabolic pathway engineering in cotton may enhance fiber properties by incorporating new traits from other genetic sources. This is an important step toward producing new generation fibers for the textile industry.

Safety of adenovirus-mediated transfer of the human cystic fibrosis transmembrane conductance regulator cDNA to the lungs of nonhuman primates

To define the toxicity of cystic fibrosis transmembrane conductance regulator gene (CFTR) gene therapy with a replication-deficient recombinant adenovirus (Av1Cf2) in a nonhuman primate model, 10(10) plaque forming units (pfu) were instilled directly through a bronchoscope into the right lung of 5 macaques, and a lower dose of 4 x 10(6) pfu was administered to the right lung of 1 macaque. One sham-treated control received phosphate-buffered saline (PBS). The macaques were evaluated sequentially by clinical examination, vital signs, weight, hematology, blood chemistry, chest radiography, pulse oximetry, and bronchoalveolar lavage (BAL) at baseline and 3-28 days post-treatment. After the period of observation, macaques were sacrificed for autopsy and histological examination. The macaques tolerated the experimental therapy clinically with no changes in body temperature, oxygen saturation, heart rate, body weight, or blood pressure. However, 1 macaque with visible evidence of aspiration at the time of initial bronchoscopy developed tachypnea with right lower lobe (RLL) pneumonia on chest radiograph and by histology. There were no changes in Hgb, Wbc, BUN, plasma electrolytes, bilirubin, or hepatic transaminases. In the macaques that received 10(10) pfu, there was a progressive increase in the number of CD8+ lymphocytes in BAL that was maximal at 28 days. Histological examination of the treated lungs of the high-dose macaques at 3 days showed marked peribronchial and perivascular cuffing by inflammatory cells and alveolar accumulation of neutrophils and macrophages. The alveolitis appeared to be resolving at 28 days, although the perivascular and peribronchial aggregates of mononuclear cells were still present. In the high-dose macaques, BAL interleukin-8 (IL-8) was increased at all time points (256-388 pg/ml versus 1-84 pg/ml at baseline and in control), whereas IL-1 beta was increased only at days 21 and 28 (341-852 pg/ml versus 30-92 pg/ml at baseline and in control). There were no increases in BAL cell counts, IL-1 beta or IL-8, and histological changes were mild in the macaque that received 4 x 10(6) pfu. Evaluation for Av1Cf2-derived human CFTR expression using RS-PCR demonstrated expression at 3, 10, and 21, but not 28 days in macaques treated with 10(10) pfu of Av1Cf2. In situ hybridization analysis demonstrated human CFTR mRNA in the alveolar regions of the lobes that received the vector at 10 and 21 days. There was no evidence of expression after treatment with 4 x 10(6) pfu. This study showed that high-dose adenoviral vector administration to the lung achieved CFTR gene transfer and expression but was associated with increased concentrations of cytokines in BAL and alveolar inflammation. A low dose, equivalent to the maximum clinical dose currently proposed for phase I trials in human subjects, was not associated with cellular or cytokine evidence of inflammation, and histological abnormalities were mild.

Prognostic value of TP53 and K-ras-2 mutational analysis in stage III carcinoma of the colon

BACKGROUND

Genetic mutations involving oncogenes and tumor-suppressor genes occur in carcinogenesis, and may affect biologic behavior of neoplasms. In this study, we analyzed the prognostic value of mutational analysis in colon carcinoma.

PATIENTS AND METHODS

Archival pathology specimens from 70 consecutive patients, resected for stage III colon carcinoma, were analyzed for point mutations by amplification and direct sequencing of exons from the K-ras-2 and the TP53 genes (topographic genotyping). Mutations were compared with adverse histopathologic features (poor differentiation, vascular and lymphatic invasion, mucin production) as prognostic markers.

RESULTS

Five-year survival was 75% in patients with nonmutated lesions, significantly lower (21%) with TP53 mutations (P = 0.01), and intermediate with K-ras-2 only (45%) or both K-ras-2 and TP53 mutations (36%). A TP53 mutation carried the highest relative risk of death (2.39; 95% confidence interval, 1.29 to 4.42; P = 0.006). There was an additive effect on the risk of death between TP53 mutations and adverse histopathologic features.

CONCLUSIONS

The information derived from mutational analysis is creating new prognostic variables that may play a role in the choice of therapy for colorectal carcinoma.

Laser skin resurfacing with the SilkTouch flashscanner for facial rhytides

BACKGROUND

Effective treatment of facial rhytides has been reported using carbon dioxide (CO2) lasers with high peak power and short exposure time which creates char-free ablation. Char-free ablation can also be created using a Silktouch flashscanner attached to a conventional CO2 laser.

OBJECTIVE

The purpose of this study is to evaluate the effectiveness of the SilkTouch flashscanner in skin resurfacing.

METHODS

The SilkTouch flashscanner attached to one of two continuous wave CO2 lasers was used to treat facial rhytides on 40 patients. Histopathology to evaluate the depth of penetration of the scanner on both CO2 lasers was performed on preauricular skin prior to excision during facelift surgery. Silicone surface replicas were obtained pre- and 2 months post-laser treatment on two patients and evaluated by optical micrometry. Clinical evaluation of all patients pre- and post-laser treatment was performed.

RESULTS

Clinical evaluation showed significant improvement of facial rhytides. Optical micrometry revealed a decrease in rhytide volume, indicating rhytide improvement.

CONCLUSION

The Silktouch flashscanner is effective for the treatment of facial rhytides.

Microsatellite instability and loss of heterozygosity in melanoma

Alterations in the repeat length of microsatellites have been identified recently in tumors arising in patients with hereditary nonpolyposis colon cancer and in several human sporadic tumors. We examined 40 sporadic melanomas and their corresponding nontumorous skin for microsatellite instability (MSI) and loss of heterozygosity (LOH) at chromosomes 2q, 3p25-26, 5q11.2-13.3, 5q21, 6q27, 9p21, 9p22-pter, 17p12, 17p12-p11.1, and 18q23. Specific loci were amplified by polymerase chain reaction, electrophoresed on polyacrylamide gels, transferred onto nylon membranes, and hybridized with 33P-end-labeled oligonucleotides. MSI was observed in eight of 40 (20%) melanomas at one of 10 loci examined. LOH was found at chromosome region 9p21 in 40%, at 9p22 in 22%, and at 17p in 13% of the informative cases. Comparison between clinicopathologic features of patients with and without MSI revealed no obvious differences. LOH at 9p21 was observed only in lesions greater than 1.5 mm in depth, suggesting that it does not represent an early event in sporadic melanoma. Our results indicate that 1) MSI is a genetic alteration in a proportion of sporadic melanoma, which may reflect a defect in genes involved in DNA replication fidelity; and 2) LOH at chromosome region 9p21 is a significant event in sporadic melanoma. The latter finding further supports the hypothesis that the 9p21 region may contain one or more tumor suppressor genes (e.g., MTS1/CDNK2) involved in the pathogenesis of melanoma.

Microsatellite instability in adenocarcinomas of the upper gastrointestinal tract. Relation to clinicopathological data and family history

We analyzed 66 adenocarcinomas arising in the upper gastrointestinal tract for microsatellite instability at eight microsatellite loci to investigate the role of these genetic alterations in the etiology of these tumors. We identified alterations in at least one locus in 11/46 adenocarcinomas of the stomach, in 2/15 adenocarcinomas arising in Barrett's esophagus, and in 1/5 adenocarcinomas of the duodenum and jejunum. Microsatellite instability in gastric tumors was found in 5/22 of intestinal, 1/3 of mixed, and 5/21 of diffuse type tumors. No relationship to the tumor stage (TNM), age, and survival time of the patients was observed. One patient had two synchronous gastric tumors both exhibiting microsatellite instability at multiple loci. His family history revealed four individuals in the maternal line afflicted with gastric carcinoma in three generations. Our data show that microsatellite instability is a genetic event in 11 to 24% of tumors of the upper gastrointestinal tract. The observation of microsatellite instability and a familial clustering of gastric tumors may suggest a genetic predisposition for a subset of gastric tumors, which may be identified by microsatellite analysis.

Expression of Fc gamma RIII defines distinct subpopulations of fetal liver B cell and myeloid precursors

We have isolated four distinct fetal liver (FL) populations based on the expression of AA4.1 and the low-affinity Fc gamma receptors type II and III (Fc gamma RII/III), and characterized them with respect to B cell, T cell, and myeloid precursor content. Polymerase chain reaction analysis revealed that the prevalent Fc gamma R isoform at this stage of FL development (day 12 of gestation) was Fc gamma RIII. Two of the four populations, one which expressed AA4.1 but little if any Fc gamma RII/III (AA4.1+), and one which expressed abundant levels of both markers (AA4.1+/FcR+), contained B cell precursors that grew and differentiated to generate VHDJH-rearranged B-lineage cells on S-17 stromal cells in the presence of IL-7. When cultured on FLST2 stromal cells only the AA4.1+ cells generated VHDJH-rearranged B-lineage cells. T cell precursors as assayed by their ability to repopulate fetal thymi in organ culture were found only in the AA4.1+ fraction. In contrast to the lymphoid precursors, myeloid precursors able to generate colonies in methyl cellulose cultures were found in all four fractions including the one which expressed Fc gamma RII/III but no AA4.1 (FcR+) and the one which expressed neither marker (AA4.1-/FcR-). The AA4.1+ population which contained both B cell and T cell precursors was enriched for precursors from many myeloid lineages including the most immature ones which generated multilineage colonies. In contrast, the AA4.1+/FcR+ population, which also contained B cell precursors, was almost devoid of myeloid precursors and the few that were detected were committed to the macrophage lineage. The population defined as FcR+ was also enriched for precursors; however, the majority of these were committed to the erythroid, the macrophage and the mast cell lineage. The fourth population which expressed neither marker (AA4.1-/FcR-) was enriched for relatively mature erythroid precursors which were not present in any of the other fractions. Together, these findings demonstrate that fractionation of FL cells on the basis of AA4.1 and Fc gamma RII/III expression distinguishes subpopulations of B cell and myeloid precursors and suggests that the low-affinity Fc gamma RIII could play a role in the development of early hematopoietic cells at this stage of ontogeny.

Neurotrophin-3 reverses experimental cisplatin-induced peripheral sensory neuropathy

Cisplatin, a widely used chemotherapeutic agent, induces a sensory neuropathy with selective loss of vibration sense and proprioception. Here we demonstrate that neurotrophin-3 (NT-3), a member of the nerve growth factor family of neurotrophic factors, restored to normal levels the reduced H-reflex-related sensory nerve conduction velocity induced by cisplatin in rats. NT-3 treatment corrected an abnormal cytoplasmic distribution of neurofilament protein in large sensory neurons in dorsal root ganglia and the reduction in the numbers of myelinated fibers in sural nerves caused by cisplatin. The NT-3-dependent reversal of cisplatin neurotoxicity thus suggests the possible use of NT-3 in the treatment of peripheral sensory neuropathy.

Characterization of mRNA for a proline-rich protein of cotton fiber

Cotton (Gossypium hirsutum L.) mRNA (H6) is expressed predominantly in fiber cells and is present during early primary cell wall formation. However, H6 protein is found to accumulate during later stages, when active secondary cell wall formation occurs, indicating possible regulation at the translational level and function in the secondary cell wall assembly. The nucleotide-derived amino acid sequence of pCK-H6 is proline rich (35 mol %) with a calculated molecular mass of 21 kD. Cotton protein H6 contains a repetitive pentameric motif (17) of alanine (serine)-threonine (serine)-proline-proline-proline. Its amino acid composition and solubility indicate that it may belong to the group of arabinogalactan proteins. Both sodium dodecyl sulfate-polyacrylamide gel electrophoresis (55 kD) and size-exclusion chromatography (77-83 kD) overestimated the size of in vitro synthesized H6 protein compared to the molecular mass derived from the nucleotide sequence (21 kD). The conformation of the molecule determined by its unusual primary structure may be the cause of its anomalous mobility. The presence of a proline-rich, arabinogalactan-type protein in cotton fiber raises the interesting possibility that it may be an integral part of the plasmalemma taking part in the development and architecture of the secondary wall of cotton fiber.

An early haematopoietic defect in mice lacking the transcription factor GATA-2

Blood cell development relies on the expansion and maintenance of haematopoietic stem and progenitor cells in the embryo. By gene targeting in mouse embryonic stem cells, we demonstrate that the transcription factor GATA-2 plays a critical role in haematopoiesis, particularly of an adult type. We propose that GATA-2 regulates genes controlling growth factor responsiveness or the proliferative capacity of early haematopoietic cells.

Inducible expression and cellular localization of insulin-degrading enzyme in a stably transfected cell line

Insulin degrading enzyme (IDE) is an evolutionarily conserved, nonlysosomal metalloprotease that has been implicated in the cellular degradation and processing of insulin. However, the site and the mode of the action of this enzyme are unclear. We have addressed these questions by establishing several Ltk- cell lines that can overexpress human insulin-degrading enzyme (hIDE) upon glucocorticoid induction. The level of overexpression of hIDE protein and transcripts in these lines correlates well with an increase in insulin degradation in both cell lysates and intact cells. Comparison of the deduced amino acid sequences of mammalian and Drosophila IDEs reveals a conserved carboxyl-terminal peroxisomal targeting sequence (A/S-K-L), suggesting that IDE may be localized in peroxisomes. To test this possibility, we determined the cellular location of the stably transfected hIDE by both immunofluorescence and immunocryoelectron microscopy. The overexpressed hIDE predominantly colocalized with catalase in peroxisomes, although IDE was also found in the cytosol at a much lower concentration. These results demonstrate that stably transfected IDE catalyzes a rate-limiting step in cellular insulin degradation and is localized predominantly in peroxisomes.

Unusually high indoor radon concentrations from a giant rock slide

In a village in western Tyrol, Austria (Umhausen, approximately 2600 inhabitants) unusually high indoor radon concentrations were measured. The medians were found to be 3750 Bq/m3 (basements) and 1160 Bq/m3 (ground floors) in winter, and 361 Bq/m3 (basements) and 210 Bq/m3 (ground floors) in summer. Maximum radon concentrations of up to 274,000 Bq/m3 were registered. The unusually high radon concentrations are due to the geology of the locality. The part of Umhausen with the highest radon concentrations is built on an alluvial fan of a giant rock slide (granitic gneiss). Measurements of the radon exhalation rate from soil showed a median of 0.4 Bq/m2/s, measurements of the radium content of rock samples yielded a median of 125 Bq/kg. The material of the rock slide is heavily fractured so that an elevated emanating power and an increased diffusion coefficient for radon in soil must be assumed. Given a diffusion coefficient of 8 x 10(-6) m2/s and an emanating power of 0.3, the median exhalation rate of 0.4 Bq/m2/s is obtained at a radium concentration of 125 Bq/kg. The rock slide is therefore considered to be the main source of radon. The abnormally high radon concentrations in Umhausen coincide with a statistically significant increase in lung cancer mortality (age and sex standardized mortality rate = 3.9, 95% C.I.: 2.9-5.1); the control population is the population of the entire Tyrol (630,000 inhabitants).

Novel insights into erythroid development revealed through in vitro differentiation of GATA-1 embryonic stem cells

Mouse embryonic stem (ES) cells lacking the transcription factor GATA-1 do not produce mature red blood cells either in vivo or in vitro. To define the consequences of GATA-1 loss more precisely, we used an in vitro ES cell differentiation assay that permits enumeration of primitive (EryP) and definitive (EryD) erythroid precursors and recovery of pure erythroid colonies. In contrast to normal ES cells, GATA-1- ES cells fail to generate EryP precursors. EryD precursors, however, are normal in number but undergo developmental arrest and death at the proerythroblast stage. Contrary to initial expectations, arrested GATA-1(-)-definitive proerythroblasts express GATA target genes at normal levels. Transcripts of the related factor GATA-2 are remarkably elevated in GATA-1- proerythroblasts. These findings imply substantial interchangeability of GATA factors in vivo and suggest that GATA-1 normally serves to repress GATA-2 during erythropoiesis. The approach used here is a paradigm for the phenotypic analysis of targeted mutations affecting hematopoietic development.

Molecular cloning of cDNAs and genes coding for beta-methylcrotonyl-CoA carboxylase of tomato

Tomato cDNA and genomic clones were isolated by using as a probe a cDNA clone that had originally been identified by its ability to direct the synthesis of a biotin-containing polypeptide in Escherichia coli. The nucleotide sequences of the newly isolated cDNAs indicate that they are clones of a single mRNA molecule. However, one of the cDNA clones contains an insertion of a sequence which we identified as an unspliced intron. The amino acid sequence deduced from the nucleotide sequence of the cDNAs showed similarity to regions of previously sequenced biotin enzymes, indicating that the isolated cDNAs code for a biotin-containing protein. Portions of the cDNAs were expressed in E. coli as glutathione S-transferase or beta-galactosidase fusion proteins. Each fusion protein was purified and used to immunize rabbits. The resulting antisera recognized a 78-kDa biotin-containing polypeptide in tomato leaf extracts. In addition, both antisera specifically inhibited beta-methylcrotonyl-CoA carboxylase activity in extracts from tomato leaves. These characterizations have identified the isolated tomato cDNAs and genes as coding for the 78-kDa biotin subunit of beta-methylcrotonyl-CoA carboxylase. Comparison of the deduced amino acid sequence of the biotin subunit of beta-methylcrotonyl-CoA carboxylase with other biotin enzymes suggest that this subunit contains the biotin carboxylase and biotin carboxyl-carrier domains.

K-ras-2 topographic genotyping of pancreatic adenocarcinoma

OBJECTIVE

To determine the frequency distribution of K-ras-2 point mutation genotypes in pancreatic adenocarcinoma and to evaluate the effectiveness of K-ras-2 genotyping as a means to predict localized disease and potential long-term survival.

DESIGN

Topographic genotyping from archival formalin-fixed, paraffin-embedded large- and biopsy-sized tissue specimens as well as cytologic fluid using polymerase chain reaction products and direct sequencing together with clinicopathologic and statistical analysis.

SETTING

Tertiary care medical center with molecular diagnostics pathology laboratory.

PATIENTS

Patients treated between 1988 and 1993 at Rhode Island Hospital, Providence, yielding 55 primary and 56 metastatic specimens of pancreatic adenocarcinoma.

RESULTS

Each primary pancreatic adenocarcinoma was found to contain one of eight specific genotypes that was maintained in all metastatic deposits of that individual tumor. Primary adenocarcinomas confined to the pancreatic bed at diagnosis were predominantly of a normal genotype (56% [14/25]). Pancreatic adenocarcinomas progressing to distant hematogenous metastasis were almost exclusively mutated (88% [7/8]; P < .005). Patients undergoing pancreatic resection (Whipple's operation) and having a normal K-ras-2-genotype (58% [11/19]) had a significantly longer survival (21.3 months) than similar patients with mutated tumors (8.2 months).

CONCLUSIONS

The findings support the feasibility of K-ras-2 topographic genotyping to identify potentially indolent disease and suggest a potentially useful role in the preoperative evaluation of pancreatic adenocarcinoma.

Isolation of a gene encoding a novel receptor tyrosine kinase from differentiated embryonic stem cells

A mouse gene encoding a receptor tyrosine kinase, designated Embryonic receptor kinase (EmRK2), was isolated from embryoid bodies (EBs) generated by differentiating embryonic stem (ES) cells in culture for 6 days. Sequence analysis of EmRK2 cDNA clones predicts a receptor with a 755 amino acid extracellular region with seven immunoglobulin-like domains, a transmembrane region, and a 552 amino acid cytoplasmic region containing the kinase domain. The kinase domain is interrupted by a stretch of hydrophilic amino acids, the kinase insert. EmRK2 is expressed in embryoid bodies, in whole embryos at day 10 and 12 of gestation, and in the embryonic yolk sac and the fetal liver. On the basis of sequence homology, EmRK2 is likely to be the mouse homologue of human flt, a receptor for vascular endothelial growth factor, and as such, could encode an endothelial cell specific receptor tyrosine kinase.

Effects of CCK8 and of the CCKB-selective agonist BC264 on extracellular dopamine content in the anterior and posterior nucleus accumbens: a microdialysis study in freely moving rats

The effects of the local administration of cholecystokinin octapeptide (CCK8) in the posterior nucleus accumbens (N. Acc.) and of BC264 (a selective CCKB agonist) in the anterior N. Acc. on dopamine (DA) neurotransmission were studied in awake rats. Microdialysis was used to quantify the extracellular contents of DA and its two metabolites, 3,4-dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA). In the posterior N. Acc., a perfusion of 10(-5) M CCK8 for 40 min (i.e. 25 pmol) increased the extracellular levels of DA, DOPAC and HVA. In contrast, 10(-4) M BC264 perfused for 40 min (i.e. 350 pmol) into the anterior N. Acc. reduced extracellular DA but did not modify DOPAC and HVA levels. These findings suggest that the CCK-DA interactions are different in various regions of the N. Acc. and emphasize the functional heterogeneity of the N. Acc., issuing in part from its particular DA innervation (mixed CCK-DA terminals only in the posterior region) but also from the distribution of the CCK fibers and binding sites in this nucleus. This microdialysis study, using perfusions of CCK compounds in the N. Acc. of freely moving rats, shows that the CCK system might play an important regulatory role in limbic DA function.

Human relaxin decreases collagen accumulation in vivo in two rodent models of fibrosis

The reproductive hormone, relaxin, inhibits collagen synthesis in vitro by normal human dermal fibroblast. In the present study, recombinant human relaxin is shown to modulate collagen accumulation and organization by mesenchymal cells in vivo in two rodent models of fibrosis: 1) fibrotic infiltration of polyvinyl alcohol sponge implants in rats, and 2) capsule formation around implanted osmotic pumps in mice. In the sponge, relaxin inhibits collagen accumulation, a measured by hydroxyproline content, in a dose-responsive manner by up to 25-29% in animals receiving 30 ng/ml relaxin, a finding supported by a decrease in collagen-specific trichrome staining in sections of sponges from relaxin-treated animals. In mice, the capsules surrounding relaxin-containing pumps are thinner and less dense than are capsules from control pumps. Ultrastructurally, control capsules are composed of densely packed parallel arrays of collagen fibrils, whereas fibrils more frequently are not packed in parallel arrays and are less abundant in treated capsules.

Expression of a gene encoding a unique protein-tyrosine kinase within specific fetal- and adult-derived hematopoietic lineages

A gene encoding a unique protein-tyrosine kinase was isolated by PCR from undifferentiated embryonic stem (ES) cells. The gene, Emsk (embryonic stem cell kinase), is expressed in a number of different lymphoid and myeloid hematopoietic lineages and has been shown to be identical to the recently isolated focal adhesion-associated kinase gene (Fadk). Within the nonlymphoid lineages analyzed, Emsk/Fadk was found to be expressed in primitive and definitive erythroid cells but not in mast cells or macrophages. All CD5+ (B-1a) B cells tested, as well as freshly isolated conventional (B-2) B cells, expressed readily detectable levels of Emsk/Fadk. Within the T-cell lineage, Emsk/Fadk was expressed in V gamma 5 gamma/delta cells as well as in immature alpha/beta cells found within the thymus. As the alpha/beta T-cell population matures and exits the thymus, expression of Emsk/Fadk appears to be down regulated. The expression pattern outlined here suggests a role for Emsk/Fadk in multiple stages of hematopoietic development and raises the possibility that the kinase encoded by this gene has a broader spectrum of activities than was initially suggested.

Fish predation and offspring survival in the prosobranch snail Viviparus ater

In this study we identified some of the predators of the freshwater snail Viviparus ater and estimated offspring survival to the end of the first summer in a natural population. Newborn V. ater were eaten by the fish Barbus barbus, Rutilus rutilus, Scardinius erythrophtalmus and Tinca tinca. Out of 137 guts of Abramis brama caught in Lake Zürich 1 contained shell fragments and an operculum of a newborn V. ater. On a 40×40 m grid near Goldbach, Lake Zürich, we counted 678 adult females of V. ater in June 1988, which together gave birth to approximately 13 300 offspring throughout the summer. In October we found 1348 V. ater of age class 0 on the grid, i.e. approximately 10% of the year's young had survived to the end of their first summer. The grid had been divided into two sections, A and B. In section A, 72 carthenware tiles had been placed as shelters for V. ater. Offspring survival was slightly but significantly higher here (10.9%) than in section B (9.6%). The observation that offspring survival in the natural habitat was 1 order of magnitude lower than in cages suggests that predation is an important cause of mortality of newborn V. ater. Average population density was 2 individuals m^-2 There was a migration from shallow (1-4 m) to deeper water (5-9 m) in September. The average distance between weekly recordings of tagged V. ater was 4.7 m in males and 3.0 m in females.

Nuclear type II estradiol binding sites and type I estrogen receptors in human endometrial cancer: a 5-year follow-up study

Type II nuclear-estrogen binding sites (type II EBS) have been postulated to play a crucial regulatory role in estrogen-stimulated uterine growth. The pathogenesis of endometrial cancer is known to be connected to estrogens. However, there are no data on type II EBS in human endometrial cancer. Therefore, we investigated the presence of nuclear type II EBS and nuclear type I estrogen receptors (ER) by radioligand-binding assays in endometrial tumorous tissues (n = 135). Determination of cytoplasmic ER and progesterone receptor (PR) concentrations were also included in the study. Estradiol (E2) and progesterone (P) hormone levels in sera of patients were determined by RIAs. In addition, all data were analyzed on 5-year survival rates. Saturation analyses of 3H-E2 binding in crude nuclear pellets (n = 5) showed two types of estradiol binding: type I ER having high affinity and low capacity and type II EBS binding estradiol with lower affinity and high capacity in a positive cooperative fashion. The nuclear type II EBS and type I ER concentrations were significantly higher in cancers of increasing grade. In contrast, a significant decrease of cytoplasmic 3H-E2 binding was detected. Cytoplasmic PR binding capacities were high in G1 and G2, but low in G3 tumors. The 5-year survival data showed nuclear type I ER to have the best correlation for prognostic value (cut-off, 0.5 pmol/mg DNA), while type II EBS had no significant impact on it. Serum E2 concentrations decreased with tumors of higher grade, but were generally still higher than the control values. The serum P levels did not alter. None of the parameters investigated here differed from control values in adenoacanthoma (n = 6), suggesting a separate pathomechanism. As type II EBS are known to be stimulated by E2 under conditions that cause uterine hyperplasia, we concluded that the higher "runaway" nuclear type II EBS levels, in contrast with the lower serum estradiol concentrations, might be connected with the strong proliferative and invasive character of higher grade endometrial adenocarcinomas. This is the first demonstration of the presence of nuclear type II EBS and their possible pathological role in human endometrial cancer, and of the high prognostic significance of nuclear type I ER to identify a subgroup having a fatal form of the disease in a 5-year survival study.

Hematopoietic commitment during embryonic stem cell differentiation in culture

We report that embryonic stem cells efficiently undergo differentiation in vitro to mesoderm and hematopoietic cells and that this in vitro system recapitulates days 6.5 to 7.5 of mouse hematopoietic development. Embryonic stem cells differentiated as embryoid bodies (EBs) develop erythroid precursors by day 4 of differentiation, and by day 6, more than 85% of EBs contain such cells. A comparative reverse transcriptase-mediated polymerase chain reaction profile of marker genes for primitive endoderm (collagen alpha IV) and mesoderm (Brachyury) indicates that both cell types are present in the developing EBs as well in normal embryos prior to the onset of hematopoiesis. GATA-1, GATA-3, and vav are expressed in both the EBs and embryos just prior to and/or during the early onset of hematopoiesis, indicating that they could play a role in the early stages of hematopoietic development both in vivo and in vitro. The initial stages of hematopoietic development within the EBs occur in the absence of added growth factors and are not significantly influenced by the addition of a broad spectrum of factors, including interleukin-3 (IL-3), IL-1, IL-6, IL-11, erythropoietin, and Kit ligand. At days 10 and 14 of differentiation, EB hematopoiesis is significantly enhanced by the addition of both Kit ligand and IL-11 to the cultures. Kinetic analysis indicates that hematopoietic precursors develop within the EBs in an ordered pattern. Precursors of the primitive erythroid lineage appear first, approximately 24 h before precursors of the macrophage and definitive erythroid lineages. Bipotential neutrophil/macrophage and multilineage precursors appear next, and precursors of the mast cell lineage develop last. The kinetics of precursor development, as well as the growth factor responsiveness of these early cells, is similar to that found in the yolk sac and early fetal liver, indicating that the onset of hematopoiesis within the EBs parallels that found in the embryo.