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Biomedical subjects

N Sacchi

Publications and source records attributed to N Sacchi.

At least 55 records · Page 3Linked to original sources
PubMed1995

Interphase cytogenetics of the t(8;21)(q22;q22) associated with acute myelogenous leukemia by two-color fluorescence in situ hybridization.

In the translocation (8;21)(q22;q22) associated with acute myelogenous leukemia (AML), part of the long arm of chromosome 8 is reciprocally translocated onto chromosome 21. At the molecular level the translocation results in the fusion of the 5' region of the AML1 gene on chromosome 21 and almost the entire CDR gene (also ETO or MTG8) on chromosome 8. The translocation can be demonstrated by techniques such as Southern blot analysis of DNA and reverse transcription-polymerase chain reaction (RT-PCR) analysis of mRNA. Neither of these methods demonstrates the translocation in individual cells. To detect the translocation at the single cell level, we used two probes, a cosmid clone containing the first five exons of AML1 and a P1 clone containing the entire CDR gene. Hybridization of the two probes to the distal and proximal side of the translocation breakpoint on chromosome 8 was expected to highlight the 8q-derivative in an interphase cell. To demonstrate the ability to identify the translocation in interphase cells using two-color FISH, these two probes were hybridized simultaneously to the Kasumi-1 cell line containing the 8;21 translocation and to t(8;21)-positive leukemic cells from a patient. Each probe was detected with a different color so that their relationship in the sample could be determined within the same interphase cell. Simultaneous hybridization of the CDR and AML1 probes to interphase cells resulted in one red and one green hybridization signal randomly located in the cell, from the hybridization to the normal chromosomes (8, 21), and one red-green pair of signals from the close hybridization of the two probes to the fusion gene on the derivative 8q-chromosome, indicating the translocation. This technique may be a useful complement for the analysis of the t(8;21), since critical information can be obtained from samples not suited for RT-PCR and conventional cytogenetic techniques. In addition, it may be useful for the assessment of minimal residual disease where RT-PCR is of limited value.

Chromosomes, Human, Pair 21↗
PubMed1995

Gender, day-night blood pressure changes, and left ventricular mass in essential hypertension. Dippers and peakers.

The finding of increased left ventricular (LV) mass in hypertensive subjects with blunted nocturnal fall in blood pressure (BP) might be an artifact of matching patients for daytime BP, with resulting higher 24-h BP in nondippers. Therefore, we compared a large number (n = 1048) of hypertensive dippers and nondippers in their LV mass at echocardiography before and after adjustment for 24-h, daytime, and nighttime ambulatory BP. In men, the difference between dippers and nondippers was not significant before and after adjustment for 24-h BP, but after adjustment for nighttime BP LV mass was greater in dippers (more properly "peakers"). In women, LV mass was greater in nondippers than in dippers both before and after adjustment for 24-h BP, while the difference between the two groups disappeared after adjustment for nighttime BP. Thus, for any given level of mean 24-h BP, a flattened diurnal BP profile is associated with a greater LV mass in hypertensive women. Daytime hypertension, either associated or not with a blunted nocturnal fall in BP, may be a sufficient determinant of LV wall thickening in men.

Adolescent↗
PubMed1995

White coat hypertension and white coat effect. Similarities and differences.

The rise in blood pressure (BP) associated with clinical visit (white coat effect) may be one basic mechanism of white coat hypertension (persistently raised clinic BP together with a normal BP outside the clinic), but the relations between white coat hypertension, white coat effect, and target organ damage have not yet been assessed on large populations. Thus, we performed 24-h noninvasive ambulatory BP monitoring and 2D-guided M-mode echocardiography in 1,333 untreated subjects with essential hypertension and 178 control normotensive subjects. White coat hypertension was defined by an average daytime ambulatory BP < 131/86 mm Hg in women and < 136/87 mm Hg in men and its prevalence was 18.9% (n = 252). The white coat effect was calculated for systolic and diastolic BP as the difference between clinic BP and average daytime ambulatory BP. Echocardiographic left ventricular mass was slightly but not significantly greater in the group with white coat hypertension than in the normotensive group (93 v 87 g/m2, P = NS), and increased in the group with ambulatory hypertension (112 g/m2, P < .01). The prevalence of white coat hypertension markedly decreased from the first to the fourth Joint National Committee V (JNC V) stage of severity of hypertension (186/559 subjects (33%) in I; 59/501 (11%) in II; 7/230 (3%) in III; 0/43 (0%) in IV; P < .001).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

Cigarette smoking, ambulatory blood pressure and cardiac hypertrophy in essential hypertension.

OBJECTIVE: To assess the role of blood pressure in the association between cigarette smoking and left ventricular mass in male and female subjects with essential hypertension. DESIGN: A case-control study with matching ratio of 1:4. PATIENTS AND METHODS: We studied 115 heavy smokers (> or = 20 cigarettes/day; 91 men) and 460 non-smokers (364 men) with essential hypertension. Subjects were matched by sex, age (within 5 years) and clinic systolic and diastolic blood pressures (within 5 mmHg). All the subjects underwent 24 h off-therapy non-invasive ambulatory blood pressure monitoring and echocardiography. RESULTS: By matching, clinic blood pressure was nearly identical in smokers and non-smokers (158/99 versus 158/98 mmHg). Daytime ambulatory blood pressure was significantly higher in the smokers than in the non-smokers (150/97 versus 143/93 mmHg), whereas night-time blood pressure did not differ between the two groups (129/79 versus 126/78 mmHg). Smokers had a higher 24 h but not clinic heart rate. Variability of systolic and diastolic blood pressure was slightly greater in smokers when expressed in terms of the standard deviation of the 24 h average (15.9/13.0 versus 14.6/12.2 mmHg), but not after correction for average blood pressure. Left ventricular mass was greater in the smokers than in the non-smokers (119 versus 110 g/m2), and this difference remained after adjustment for clinic blood pressure and other related covariates. However, when clinic blood pressure was replaced by daytime ambulatory blood pressure in the equation, adjusted values of left ventricular mass did not differ between the smokers and the non-smokers (113 versus 112 g/m2). CONCLUSION: In patients with essential hypertension, heavy cigarette smoking (> or = 20 cigarettes/day) is associated with a definite increase in left ventricular mass through a rise in whole-day blood pressure. A pressor mechanism of that type may not be detected by the standard measurement of blood pressure in the clinic, which would make ambulatory blood pressure monitoring a valuable diagnostic tool in this setting.

Blood Pressure↗
PubMed1995

Identical fusion transcript associated with different breakpoints in the AML1 gene in simple and variant t(8;21) acute myeloid leukemia.

Fluorescence in situ hybridization (FISH) and/or RNA-based polymerase chain reaction (RT-PCR) were used to analyze the breakpoints within the AML1 gene and the AML1 fusion transcripts in t(8;21) acute myeloid leukemia (AML). Twenty-two patients presented with the simple t(8;21)(q22;q22) and one with a complex variant t(8;2;16;21). In eight cases we used FISH with AML1 cosmid probes on metaphase chromosomes as well as RT-PCR to detect the junctions of MAL1/CDR (ETO,MTG8). Five cases were analyzed by FISH alone and ten cases by RT-PCR alone. By FISH we could identify three groups according to the distribution of the fluorescent signal. Signals were found in group 1 on chromosomes 21 and 21q+, in group 2 on chromosomes 21, 21q+ and 8q- and in group 3 on chromosomes 21 and 8q-. In all groups we could detect an identical AML1/CDR fusion transcript. This transcript showed splicing of AML1 exon 5 onto CDR. Thus regardless of the heterogeneity suggested by FISH, all the breakpoints in the AML1 gene were clustered in the same intro between exons 5 and 6. Our results bring to over one hundred the number of t(8;21) cases in which an identical translocation could be detected at molecular level by RT-PCR. The high sensitivity of the technique makes it suitable for the diagnosis of this translocation in different stages of the disease. The impact of the molecular detection of t(8;21) cells in clinical remission as far as the treatment and the management of the disease are concerned deserves further discussion.

Acute Disease↗
PubMed1994

Cephem sulfones as inactivators of human leukocyte elastase. 5. 7 alpha-Methoxy- and 7 alpha-chloro-1,1-dioxocephem 4-ketones.

Studies on cephem sulfones as inhibitors of human leukocyte elastase (HLE) have been extended to the new class of cephem 4-ketones. tert-Butyl and phenyl ketones were prepared from 4-carboxycephem derivatives, at either the sulfide or sulfone oxidation level, by chemoselective Grignard reaction. Obtained products were functionalized with heterocyclothio and acyloxy substituents at C-3', C-2, or both positions. tert-Butyl ketones of the 7 alpha-chlorocephem series were in general at least as potent as the corresponding esters at inhibiting the enzyme, but improvements in hydrolytic stability were only marginal. On the other hand, tert-butyl ketones of the 7 alpha-methoxycephem series combined potent biochemical activity with acceptable hydrolytic stability, thus overstepping the esters, thiolesters, and amides reported previously. In particular, the tert-butyl ketones possessing a heterocyclothio group at C-3' or C-2 were at least as active as the corresponding tert-butyl esters but 1 order of magnitude more stable in physiologic buffers (pH 7.4, 37 degrees C). Introduction of acyloxy groups at C-2 delivered the most potent HLE inhibitors of the cephem class ever reported, with inhibition parameters often outside the determination limits of our standard protocol (second-order rate constant kon > 2,000,000 M-1 s-1; Ki at steady state < 2 nM). Keto-enol tautomerism was found to depress activity and boost hydrolytic stability. Thus, double substitution with heterocyclic thiols produced compounds with diverging properties, according to the extent of enolate formation at the investigated pH (7.4): the weakly acidic tert-butyl ketones (pKa > or = 5.8) proved to be potent inhibitors (kon over 10(4) M-1 s-1) with reasonable hydrolytic stability (t1/2 = 30-75 h), while the phenyl ketones (pKa < 4) were fair inhibitors (kon over 10(3) M-1 s-1; Ki at steady state approximately 50 nM) with hydrolytic half-lives exceeding 1000 h. Selected compounds efficiently inhibited the degradation of insoluble bovine neck elastin by HLE in a concentration-dependent manner. Intracellular HLE of polymorphonuclear leukocytes was in general unaffected; however, a lipophilic cephem sulfone apparently able to inactivate the enzyme in living cells was identified.

Cells, Cultured↗
PubMed1994

AML1 fusion transcripts in t(3;21) positive leukemia: evidence of molecular heterogeneity and usage of splicing sites frequently involved in the generation of normal AML1 transcripts.

The t(3;21)(q26;q22) is associated with chronic myelogenous leukemia in blast crisis (CML-BC), leukemia evolving from (therapy-related) myelodysplasia, and with leukemia following other hematopoietic proliferative diseases. Molecular cytogenetic analysis and cloning of a few t(3;21) cases indicate that the breakpoints are quite heterogeneous even within a specific clinical phenotype. Interestingly some of the (3;21) breakpoints involve the AML1 gene previously found rearranged in the t(8;21) associated with acute myelogenous leukemia. AML1 is related to the Drosophila gene runt and is the human counterpart of the gene for the alpha subunit of the nuclear polyoma enhancer binding protein (PEBP2) also known as the core binding factor (CBF). In the t(3;21) AML1 was found rearranged with EAP, a gene on chromosome 3 encoding a small ribosomal protein, as well as with EV11, another gene on chromosome 3. Here we report our study of six cases of t(3;21). By using fluorescence in situ hybridization (FISH) analysis and AML1 probes we could conclude that at least in two CML-BC cases the breakpoint occurred in the AML1 intron that is disrupted by the t(8;21). An AML1/EAP fusion transcript, different from the one described in a therapy-related myelodysplasia, was detected in both CML-BC cases. This transcript is expected to result in a predicted protein containing the AML1 nuclear binding domain with an attached stretch of 17 amino acids unrelated to the EAP small ribosomal protein. In the other t(3;21) patients we could not detect an AML1/EAP transcript or an AML1/EV11 transcript. This result suggests heterogeneity of the t(3;21) at the molecular level. The AML1 chimeric transcripts identified so far, both in the t(3;21) and in the t(8;21), diverge from the normal transcripts either after exon 5 or exon 6. Here we show that in normal AML1 transcripts different splicing events are seen to occur after AML1 exon 5 as well as exon 6.

Amino Acid Sequence↗
PubMed1993

Identification of the chromosome 14 origin of a C-negative marker associated with a 14q32 deletion by chromosome painting.

A constitutional chromosome 14 rearrangement was observed in a female with a psychodevelopmental disorder. Karyotype analysis using a variety of chromosome techniques, QFQ, GTG, CBG, Ag-NOR and DA-DAPI, showed a deletion of chromosome 14q32.1-qter region in association with a supernumerary marker chromosome. The marker, resembling a submetacentric, approximately half the size of a G group chromosome is C band and Ag-NOR negative. The heteromorphism of the satellites showed that the deleted chromosome 14 is paternal in origin. Chromosome painting using an Alu-PCR probe specific for the human chromosome 14 and fluorescent in situ hybridization (FISH) showed that the marker contains chromosome 14q32 sequences. It is likely that the marker was generated from the deleted chromosome 14 region through a complex rearrangement.

Abnormalities, Multiple↗
PubMed1992

Transcriptionally active chimeric gene derived from the fusion of the AML1 gene and a novel gene on chromosome 8 in t(8;21) leukemic cells.

In the t(8;21)(q22;q22) of acute myelogenous leukemia (AML), the breakpoint on chromosome 21 disrupts the AML1 gene, generally in the intron between exons 5 and 6. To isolate fusion transcripts of AML1, and an as yet unidentified gene on chromosome 8 involved in the rearrangement, we used rapid amplification of cDNA ends (RACE) and primers for AML1 exons 5 and 6. A fusion transcript was identified by 3' RACE in the RNA of t(8;21) leukemic cells that also express multiple normal AML1 transcripts. This result clearly indicates that at least one transcriptionally active chimeric gene is generated by the chromosome translocation. This gene on the 8q- derivative represents the fusion between the 5' portion of the AML1 gene with the 3' portion of a chromosome 8 gene that contains a region of sequence homology with the cyclin D2 gene, here referred to as the CDR gene (cyclin D-related gene). The chimeric gene is probably responsible for the pathogenesis of the 8;21 AML. This finding makes it possible to detect the translocation at the molecular level, thus improving the diagnosis and monitoring of the disease in leukemic patients.

Base Sequence↗
PubMed1991

DNA sequences of chromosome 21-specific YAC detect the t(8;21) breakpoint of acute myelogenous leukemia.

The t(8;21)(q22;q22) is a nonrandom translocation specifically marking blasts of acute myelogenous leukemia (AML) with undifferentiated phenotype. The breakpoint on chromosome 21 involved by this rearrangement has been precisely localized relative to cloned DNA markers by physical and genetic linkage analysis enabling the use of positional cloning for its isolation. Yeast artificial chromosome (YAC) clones for loci proximal (D21S65) and distal (ERG) to the (21q22) breakpoint have been developed and their chromosome 21 origin and location relative to the breakpoint has been established. By using in situ hybridization analysis, a 240 kb YAC clone for the D21S65 locus clearly identified both derivative chromosomes of the (8;21) translocation in metaphase spreads of leukemia blasts with the rearrangement. The characterization of the DNA sequences contained in this 240 kb YAC can reveal the functional consequences of their derangement in leukemia with abnormalities of the (21q22) region.

Base Sequence↗
PubMed1991

Single-cell detection of ets-1 transcripts in human neuroectodermal cells.

The genes of the ets family are thought to code for a novel class of transcriptional factors. These proteins have a specific DNA-binding domain different from the basic domain of both the helix-loop-helix and leucine zipper families of DNA-binding proteins. The ets-1 gene product has been shown to bind to the enhancer region of the human T-cell receptor alpha gene during thymocyte ontogeny. This finding explains the high expression of ets-1 observed in T cells and the correlation between ets-1 expression and the expression of the T-cell receptor gene during fetal development. The ets-1 gene is also possibly biologically active in neural cells. By using RNA in situ hybridization analysis, we demonstrate the presence of ets-1 transcripts in cells of peripheral embryonal neuroectodermal tumors, specifically neuroepithelioma and neuroblastoma. In addition, the gene is found transcribed in Ewing's sarcoma, postulated to be ontogenetically related to tumors derived from the neural crest.

Gene Expression↗
PubMed1990

ETS family of genes in leukemia and Down syndrome.

The human ETS2 and ERG genes are members of the ETS gene family, with sequence homology to the viral ets gene of the avian erythroblastosis retrovirus, E26. These genes are located on chromosome 21 and molecular genetic analysis of Down syndrome (DS) patients with partial trisomy 21 suggested that ETS2 may be a gene within the minimal DS genetic region. We have, in fact, been able to confirm the presence of the ETS2 gene dosage in triplicate occurring in occult human 21 chromosome abnormalities. It is known that ERG and ETS2 gene translocations occur in certain specific leukemias associated with defined chromosome rearrangements [e.g., t(8;21)]. Moreover, it is known that DS individuals are at greater risk for leukemic disease than their normal familial cohorts, implying that trisomy of that region of human chromosome 21 may play a role in the development of this type of neoplasia. The human ETS genes, first identified in our laboratory, are highly conserved, being found from lower organisms, like Drosophila and sea urchin, to humans. In mammals, the ETS genes are structurally distinct, located on separate chromosomes; they are transcriptionally active and differentially regulated. The ETS2 protein is phosphorylated and turns over with a half-life of approximately 20 min. After activation with the tumor promoter, TPA, the level of ETS2 elevates 5- to 20-fold. The properties of the ETS2 protein, such as nuclear localization, phosphorylation, rapid turnover, and response to protein kinase C, indicate that this protein belongs to a group of oncogene proteins thought to have regulatory functions in the nucleus. In the mouse thymus ets-1 and ets-2 are 8-10-fold higher, respectively, in the CD4+ subset than in other subsets examined, suggesting a role in T-cell development for these genes. Cells transfected with the cellular ets-2 gene, expressing higher levels of ets-2 products, showed a stimulated proliferation response, abolished their serum requirement and formed colonies in soft agar that could induce tumors in nude mice. Collectively, these data suggest that this family of genes might play a role in controlling specific steps of the signaling transduction pathway. Thus, the ETS genes, as other genes with homology to viral oncogenes, might be instrumental in regulating cellular growth and differentiation, as well as organismal development.

Animals↗
PubMed1990

Physical mapping of the human chromosome 11q23 region containing the ataxia-telangiectasia locus.

Two breakpoints within chromosome 11q23 were characterized with 29 DNA probes to establish a physical map of the region. This region is notable in that it contains at least 14 functional genes which are also syntenic in the mouse (chromosome 9). Chromosome 11q23 includes these markers: STMY, CLG, NCAM, DRD2, APOA1, APOC3, APOA4, CD3E, CD3D, CD3G, PBGD, THY1, ets-1, and cbl-2. The two breakpoints, herein called "X;11" and "4;11," defined a region of approximately 8 cM containing the APO and CD3 complexes as well as the polymorphic marker D11S29. DRD2 localized centromeric to the X;11 breakpoint despite evidence for close genetic linkage to D11S29, suggesting that DRD2 lies close to the X;11 breakpoint. THY1, PBGD, and cbl-2 localized telomeric to the 4;11 breakpoint and thus to the [D11S29--APO--CD3] grouping as well. The physical map helps to correlate the cytogenetic and linkage maps of this region. It also suggests that the human 11q23 syntenic grouping is inverted with respect to its murine counterpart. Based on this physical map and on our primary linkage map of the 11q23 region, we are able to confirm a preliminary localization of the gene for ataxia-telangiectasia group A (ATA) to a region centromeric to the interval defined by D11S144 (pYNB3.12) and THY1.

Animals↗