Consolidation and maintenance therapy with lenalidomide, bortezomib and dexamethasone (RVD) in high-risk myeloma patients.

Prior studies have shown that myeloma patients exhibiting either genetically defined high-risk disease or plasma cell leukemia have a poor outcome with a median overall survival (OS) of ≤3 years. Results of IFM 2005-01 and 02 suggest that relatively limited bortezomib-containing induction regimens did not produce a major survival benefit among these patients. However, results of recent studies suggest that combination therapy may benefit these patients when given early and again later in the treatment. We evaluated a combination maintenance/consolidation regimen (RVD) following autologous stem cell transplant (ASCT) for high-risk patients to evaluate the impact of this approach on outcome. Following initiation of RVD maintenance, 51% of patients achieved stringent complete response (sCR), with 96% achieving at least VGPR as best response. Median progression free survival (PFS) for all patients is 32 months with a 3-year OS of 93%. The regimen was well tolerated with no grade 3/4 neuropathy. Early ASCT followed by RVD maintenance is a promising strategy for high-risk myeloma patients and delivered excellent response rates, and promising PFS and OS.

Stimulation of mitotic recombination events by high levels of RNA polymerase II transcription in yeast.

The impact of high levels of RNA polymerase II transcription on mitotic recombination was examined using lys2 recombination substrates positioned on nonhomologous chromosomes. Substrates were used that could produce Lys(+) recombinants by either a simple (noncrossover) gene conversion event or a crossover-associated recombination event, by only a simple gene conversion event, or by only a crossover event. Transcription of the lys2 substrates was regulated by the highly inducible GAL1-10 promoter or the low-level LYS2 promoter, with GAL1-10 promoter activity being controlled by the presence or absence of the Gal80p negative regulatory protein. Transcription was found to stimulate recombination in all assays used, but the level of stimulation varied depending on whether only one or both substrates were highly transcribed. In addition, there was an asymmetry in the types of recombination events observed when one substrate versus the other was highly transcribed. Finally, the lys2 substrates were positioned as direct repeats on the same chromosome and were found to exhibit a different recombinational response to high levels of transcription from that exhibited by the repeats on nonhomologous chromosomes. The relevance of these results to the mechanisms of transcription-associated recombination are discussed.

Detection of mosaicism in amniotic fluid cultures: a CYTO2000 collaborative study.

PURPOSE: To evaluate the assumptions on which the American College of Medical Genetics (ACMG) Standards and Guidelines for detecting mosaicism in amniotic fluid cultures are based. METHODS: Data from 653 cases of amniotic fluid mosaicism were collected from 26 laboratories. A chi-square goodness-of-fit test was used to compare the observed number of mosaic cases with the expected number based on binomial distribution theory. RESULTS: Comparison of observed data from the in situ colony cases with the expected distribution of cases detected based on the binomial distribution did not reveal a significant difference (P = 0.525). CONCLUSIONS: The empirical data fit the binomial distribution. Therefore, binomial theory can be used as an initial discussion point for determining whether ACMG Standards and Guidelines are adequate for detecting mosaicism.

Neural-tube defects are associated with low concentrations of cobalamin (vitamin B12) in amniotic fluid.

While folate supplementation reduces the risk of recurrent neural-tube defects (NTD), both folate and cobalamin deficiencies may be independent risk-factors for neural-tube defects. Folate-dependence and impaired remethylation of homocysteine are implicated as mechanisms for NTD. There are few references reported for folate, cobalamin, homocysteine and methionine in the fetal compartment. This case-controlled pilot study of amniotic fluid (AF) samples derived from 16 NTD pregnancies and 64 age-matched controls quantities total homocysteine (tHcy), total cysteine (tCys), folate, cobalamin (B12), and methionine. Only decreased AF B12 concentrations were found (150 pg/ml versus 540 pg/ml, P < 0.02). Since cobalamin, folate and homocysteine participate in the remethylation of homocysteine, via methyl transfer from 5-methyltetrahydrofolate to B12, to methionine, we compared ratios of these methionine synthase (EC 2.1.1.13)-related intermediates. The ratio of B12/folate for NTD versus controls was 48 (34-90) versus 126 (123-182), P < 0.001. The ratio of methionine/(folate x tHcy) was 1.4 (1.2-2.2) versus 2.7 (2.4-3.3), P < 0.001. We conclude that AF from pregnancies with NTD have lower B12 concentrations, and that ratios of product to substrate(s) of homocysteine remethylation suggest impaired methionine synthase in the fetal compartment through the early second trimester.

Unique mosaicism of tetraploidy and trisomy 8: clinical, cytogenetic, and molecular findings in a live-born infant.

We report on a live-born infant with mosaicism of tetraploidy and trisomy 8 who had craniofacial abnormalities, cardiac and genitourinary defects, agenesis of the corpus callosum, and anomalies of limbs. The infant died at age 14 weeks. Molecular studies were done on peripheral blood lymphocytes and cultured amniocytes to determine the origin of the cytogenetic abnormalities. On the basis of the results, we describe a possible mechanism to explain these abnormalities. To our knowledge, this infant represents the first reported case of mosaic trisomy 8 with a tetraploid cell line.

Incidence and significance of chromosome mosaicism involving an autosomal structural abnormality diagnosed prenatally through amniocentesis: a collaborative study.

Among 179,663 prenatal diagnosis cases collected from ten institutions and two publications, 555 (0.3 per cent) were diagnosed as having chromosome mosaicism. Of these, 57 (10.3 per cent) were mosaic for an autosomal structural abnormality, 28 (5 per cent) for a sex chromosome structural abnormality, and 85 (15.3 per cent) were mosaic for a marker chromosome. Ninety-five cases of prenatally diagnosed mosaicism with a structural abnormality in an autosome and a normal cell line, and with a known phenotypic outcome, were collected for karyotype-phenotype correlations through our collaboration (40 cases), a prior survey (26 cases), and published reports (29 cases). They included 13 balanced reciprocal translocations, one unbalanced reciprocal translocation, four balanced Robertsonian translocations, four unbalanced Robertsonian translocations, four inversions, 17 deletions, three ring chromosomes, 19 i(20q), seven +i(12p), six other isochromosomes, and 17 partial trisomies resulting from a duplication or other rearrangement. All cases mosaic for a balanced structural rearrangement resulted in a normal phenotype. All cases of 46/46,i(20q) resulted in normal liveborns. Five of seven cases with 46/47,+i(12p) had an abnormal phenotype compatible with Killian-Pallister syndrome. The overall risk for an abnormal outcome for a mosaic case with an unbalanced structural abnormality, excluding 46/46,i(20q) and 46/47,+i(12p), is 40.4 per cent. In the same category, the study also suggested a correlation between the percentage of abnormal cells and an abnormal phenotype. For mosaicism involving a terminal deletion, the possibility of a familial fragile site should be considered.

DNA methylation represses FMR-1 transcription in fragile X syndrome.

Fragile X syndrome is the most frequent form of inherited mental retardation and segregates as an X-linked dominant with reduced penetrance. Recently, we have identified the FMR-1 gene at the fragile X locus. Two molecular differences of the FMR-1 gene have been found in fragile X patients: a size increase of an FMR-1 exon containing a CGG repeat and abnormal methylation of a CpG island 250 bp proximal to this repeat. Penetrant fragile X males who exhibit these changes typically show repression of FMR-1 transcription and the presumptive absence of FMR-1 protein is believed to contribute to the fragile X phenotype. It is unclear, however, if either or both molecular differences in FMR-1 gene is responsible for transcriptional silencing. We report here the prenatal diagnosis of a male fetus with fragile X syndrome by utilizing these molecular differences and show that while the expanded CGG-repeat mutation is observed in both the chorionic villi and fetus, the methylation of the CpG island is limited to the fetal DNA (as assessed by BssHII digestion). We further demonstrate that FMR-1 gene expression is repressed in the fetal tissue, as is characteristic of penetrant males, while the undermethylated chorionic villi expressed FMR-1. Since the genetic background of the tissues studied is identical, including the fragile X chromosome, these data indicate that the abnormal methylation of the FMR-1 CpG-island is responsible for the absence of FMR-1 transcription and suggests that the methylation may be acquired early in embryogenesis.

The diagnostic value of upper gastrointestinal radiography.

We reviewed the indications for and results of 788 consecutive upper gastrointestinal radiographs (UGIs) performed for ambulatory patients. Sixty-three percent of tests were ordered for the evaluation of abdominal pain, dyspepsia, or esophageal reflux. Of these tests, only 4.8% yielded results of major clinical importance to patient management. The yield for patients greater than 50 years of age was greater than for patients less than 50, 6.9 versus 3.0% (p = 0.04). There was a significant increase in yield with increasing age (chi trend = 11.6, p less than 0.001). Among patients with an indication of esophageal reflux alone (n = 62), there were no patients younger than age 60 with a test result that would significantly affect therapy or outcome. Among patients evaluated for fecal occult blood or weight loss (n = 120), 11.7% of tests ordered showed a finding of major clinical importance. In this group, the yield was higher in those greater than or equal to 50 years of age than in those less than 50, 14.7 versus 6.7%, (p = 0.2). These results indicate that UGIs ordered to evaluate pain or symptoms of esophageal reflux in the absence of bleeding or weight loss rarely yield results that significantly influence therapy. Such patients may be best served by an initial trial of empiric therapy or some other test. The UGI has greatest value when indications for it include bleeding or weight loss.

Mapping and gene order of U1 small nuclear RNA, endogenous viral env sequence, amylase, and alcohol dehydrogenase-3 on mouse chromosome 3.

Linkage was established between a number of genes that map on chromosome 3 by studying the distribution patterns of DNA polymorphisms and protein electrophoretic mobility polymorphisms in recombinant inbred (RI) strains of mice. This analysis resulted in the following suggested gene order between the newly assigned genes and previously mapped genes: gamma-fibrinogen (Fgg), Xmmv-22 of mink cell focus-inducing (MCF) virus, U1b small nuclear RNA gene cluster (Rnu-1b), amylase (Amy-1,2), cadmium resistance (cdm), alcohol dehydrogenase-3 (Adh-3), alcohol dehydrogenase-1 (Adh-1). In situ hybridization to chromosome spreads confirmed the assignment of the Ulb small nuclear RNA (snRNA) gene cluster and the gamma-fibrinogen gene to the center of chromosome 3.

Assignment of the Ly-6--Ril-1--Sis--H-30--Pol-5/Xmmv-72--Ins-3--Krt-1--Int-1 --Gdc-1 region to mouse chromosome 15.

Previous work has demonstrated linkage between Ly-6, H-30, and a locus, Ril-1, that affects susceptibility to radiation-induced leukemia. Results or preliminary linkage analyses suggested further that the cluster might be linked to Ly-11 on the proximal portion of mouse chromosome 2. Using molecular probes to examine somatic cell lines and recombinant inbred and congenic strains of mice, we have re-evaluated these linkage relationships. A cloned genomic DNA fragment derived from a retroviral site has been used to define a novel locus, Pol-5, that is tightly linked to both H-30 and Ril-1 as shown by analysis of the B6.C-H-30c congenic mouse strain. Following the segregation of the Pol-5 mouse-specific DNA fragment in a series of somatic cell hybrids carrying various combinations of mouse chromosomes on a rat or Chinese hamster background mapped Pol-5 to mouse chromosome 15. During the course of these studies, restriction fragment length polymorphisms were defined associated with several loci, including Pol-5, Ly-6, Sis, Ins-3, Krt-1, Int-1, and Gdc-1. Three of these loci, Sis, Int-1, and Gdc-1, have been previously mapped to chromosome 15 by others using somatic cell hybrids or isoenzyme analyses. Following the inheritance of these eight loci in recombinant inbred strains of mice allowed the definition of a linkage group on the chromosome with the order Ly-6--Ril-1--Sis--H-30--Pol-5--Ins-3--Krt-1--Int-1--Gdc-1. Analyses of alleles inherited as passengers in B6.C-H-30c, C3H.B-Ly-6b, and C57BL/6By-Eh/+ congenic mouse strains and in situ hybridization experiments support the above gene order and indicate further that the cluster is located on distal chromosome 15, with Ly-6 and Sis near Eh.

Aniridia and Wilms' tumor in a child constitutionally mosaic for 11p-;12q+: a new chromosomal change also present in Wilms' tumor cells of the blastema type.

A child with congenital aniridia was assessed closely, by repeated abdominal ultrasound examinations, beginning at birth. The Wilms' tumor subsequently discovered and removed was analyzed karyotypically and found to have some cells with a terminal deletion of chromosome 11; in other cells this deletion was associated with a duplication in the long arm of chromosome 12. These findings were identical to those observed in the patient's peripheral blood mononuclear cells. This case further substantiates the association between changes in chromosome 11 and Wilms' tumor and demonstrates how chromosomal abnormalities in early infancy may lead to the development of Wilms' tumor.

Effect of rabbit antimouse brain serum on marrow cells capable of curing W/Wv mice.

The W/Wv mouse has a recessively inherited defect in hematopoietic stem cells (HSC) but can be cured of its hematopoietic abnormalities by infusion of marrow from a co-isogeneic, +/+ mouse. The "curative" cell for the W/Wv is thought to be a subcompartment of the HSC that is capable of forming hematopoietic spleen colonies (CFU-S) in irradiated mice. The curative HSC must have a very high proliferative potential and it is known that HSC with variable degrees of proliferative potential are found within the CFU-S compartment. Rabbit antimouse brain serum (RAMBS) was used to treat +/+ marrow and its effect upon CFU-S and upon curative cells was compared with the effect of normal rabbit serum (NRS) or of sham treatment. CFU-S were reduced to 70%-79% of control by NRS and to 8%-9% by RAMBS. Curative cells for the W/Wv were not detectably reduced by NRS; they were reduced by RAMBS, but to only approximately 20%-30% of control. Thus, it appeared to a certain degree that RAMBS spared HSC with a high proliferative potential when compared with its effect on the entire CFU-S compartment.

Lactate infusion in anxiety research: its evolution and practice.

The unpredictability of spontaneous unexpected panic attacks has inhibited the controlled study of this phenomenon. Previous studies demonstrated that an increase in blood lactic acid occurred concomitant with symptoms of anxiety in anxiety-prone patients who underwent standard physical exercise. The question of whether these patients had an excessive sensitivity to lactate led to the development of the lactate infusion model, in which anxiety is induced in a controlled environment. The history and current application of the lactate infusion model in the study of neurochemical correlates of panic are described, and a methodology for lactate infusion procedures is outlined.

Evolution and organization of the fibrinogen locus on chromosome 4: gene duplication accompanied by transposition and inversion.

Human fibrinogen cDNA probes for the alpha-, beta-, and gamma-polypeptide chains have been used to isolate the corresponding genes from human genomic libraries. There is a single copy of each gene. Restriction endonuclease analysis of isolated genomic clones and human genomic DNA indicates that the human alpha-, beta-, and gamma-fibrinogen genes are closely linked in a 50-kilobase region of a single human chromosome: the alpha-gene in the middle flanked by the beta-gene on one side and the gamma-gene on the other. The alpha- and gamma-chain genes are oriented in tandem and transcribed toward the beta-chain gene. The beta-chain gene is transcribed from the opposite DNA strand toward the gamma- and alpha-chain genes. The three genes have been localized to the distal third of the long arm of chromosome 4, bands q23-q32, by in situ hybridization with fibrinogen cDNAs and by examination of DNA from multiple rodent-human somatic cell hybrids. Alternative explanations for the present arrangement of the three fibrinogen genes involve either a three-step mechanism with inversion of the alpha/gamma-region or a two-step mechanism involving remote transposition and inversion. The second more simple mechanism has a precedent in the origin of repeated regions of the fibrinogen and immunoglobulin genes.

Localization of the human myelin basic protein gene (MBP) to region 18q22----qter by in situ hybridization.

A restriction endonuclease fragment derived from a cloned portion of human genomic DNA corresponding to the myelin basic protein gene has been used to map the position of this gene by in situ hybridization to human metaphase chromosomes. Ten percent of the radioactively labeled sites observed were on chromosome 18. Eighty-four percent of the grains on chromosome 18 were located within the region corresponding to 18q22----qter. This represents a greater than 10-fold increase in labeling at this position over the background grain distribution found along all of the other chromosomes.

The T cell receptor beta chain genes are located on chromosome 6 in mice and chromosome 7 in humans.

Homologous clones that encode the beta chain of the T cell antigen receptor have been isolated recently from both murine and human cDNA libraries. These cDNA clones have been used in connection with interspecies hybrid cell lines to determine that the murine T cell receptor gene is located on chromosome 6 and the human gene on chromosome 7. In situ hybridization confirms these data and further localizes these genes to band B of chromosome 6 in the mouse and bands 7p13-21 in the human genome. The organization of the T cell antigen receptor J beta gene segments and C beta genes appears to be conserved, since very few intraspecies polymorphisms of restriction fragment length have been detected in either mouse or human DNA.

Transplantation of chromosomally marked syngeneic marrow cells into mice not subjected to hematopoietic stem cell depletion.

The percentage of donor-host chimerism was determined 4-6 weeks or six months after injection of normal bone marrow cells into normal syngeneic or coisogeneic recipient mice. Donor-recipient pairs had chromosome markers that provided easy identification of metaphase cells. The percentage of donor cells in marrow or spleen ranged from 0 to 16% and this percentage was independent of the age of recipient or attempts to stimulate hematopoiesis in donor and/or host mice. In adult C57BL/6 mice there was a roughly linear dose-response relationship between cell dose and percentage of chimerism. There was no apparent dose-response relationship for AKR mice. The percentage of donor cells in the spleen was correlated to that seen in the marrow of recipients. Neonatal mice given the same intraperitoneal marrow cell dose as weanlings, but a larger number of cells relative to their own marrow mass, did not show a larger percentage of chimerism than weanlings. Similarly, weanlings given the same intravenous dose as adults showed no greater degree of chimerism than adults. Temporary anemia, induced by bleeding donors prior to cell collection, or more chronic hemopoietic stimulus (produced by injecting recipients with phenylhydrazine prior to cell injection with subsequent bleeding at intervals) did not result in an increased percentage of chimerism. These results indicate that there are "empty" sites in bone marrow of normal mice in which injected hematopoietic stem cells can lodge and grow.

Aging and hematopoiesis. II. The ability of bone marrow cells from young and aged mice to cure and maintain cure in W/Wv.

The proliferative ability of hematopoietic stem cells (HSC) was compared in young and aged mice. Infusion of coisogeneic marrow cures the hematopoietic defect of the W/Wv, a mouse with a recessively inherited defect in stem cells, including HSC. W/Wv were cured with equal frequency by relatively small doses of marrow (5 X 10(4) nucleated cells, an average of 2-3 "curative" HSC per aliquot) from 3-month-old or 27-month-old +/+ donors. After functioning in the originally cured W/Wv for 26 months, the marrow was used to cure other W/Wv. After functioning in secondary recipients for 16 months, it was, in turn, used to cure still other W/Wv. There was no difference between "old" and "young" bone marrow with respect to the frequency of cure in W/Wv, the duration of cure--or, in regard to marrow from cured W/Wv, the number of nucleated and peroxidase-positive cells per humerus and the number of cells capable of producing spleen colonies in irradiated recipients. Thus, these studies fail to disclose any evidence for a proliferative limitation for old as compared to young HSC.