AML-1 gene rearrangement and AML-1-ETO gene expression as molecular markers of acute myeloblastic leukemia with t(8;21)

Rearrangements of the AML-1 gene on chromosome 21 as well as transcriptional expression of AML-1-ETO fusion gene were studied in 35 leukemic patients with t(8;21)(q22;q22). A panel of probes generated from the AML-1 gene regions flanking the breakpoint on chromosome 21 allowed us to detect the rearrangement in 24 out of 29 patients. A specific nested reverse transcriptase/polymerase chain reaction (RT/PCR) was developed to detect the t(8;21), either at diagnosis or as minimal residual disease. PCR amplification products were obtained in ten out of 11 patients investigated, and the sensitivity of the reaction was estimated to be between 1 x 10(4) and 1 x 10(-5) cell. An AML-1 rearrangement was also detected in one patient with 8q- and only one chromosome 21, but without 21q+. This indicated that the molecular rearrangement of the der(8) chromosome is more important than the reciprocal one in the malignant process.

No structural mutation in the dopamine D2 receptor gene in alcoholism or schizophrenia. Analysis using denaturing gradient gel electrophoresis

OBJECTIVE

To examine the dopamine D2 receptor (DRD2) gene coding sequences for abnormalities associated with schizophrenia or alcoholism and thereby help to resolve the controversy surrounding the reported association of alcoholism with a restriction fragment length polymorphism located close to the DRD2 gene.

DESIGN

Mutational analysis of complete DRD2 gene coding sequences by denaturing gradient gel electrophoresis followed by direct nucleotide sequencing of detected variants.

SETTING

Patients and controls from clinical and epidemiologic collections in the United States and Europe.

PATIENTS

A total of 253 unrelated individuals, including 106 patients with schizophrenia, 113 with alcoholism, and 34 controls. For alcoholism we included patients from previously published series in which an association of illness with allele A1 was reported (Taql site 3' to the DRD2 gene) and from other published series in which nonconfirmations of this association were reported. Nearly all persons examined were white.

MAIN OUTCOME MEASURES

Frequency of nonsilent variations in DRD2 gene DNA sequences in the different diagnostic groups.

RESULTS

We found three infrequent DNA variants that predict altered amino acid sequence of the receptor. None of these is associated with either alcoholism or schizophrenia.

CONCLUSION

No structural coding abnormalities in the DRD2 gene are present in alcoholism or schizophrenia.

Acute promyelocytic leukemia: clinical relevance of two major PML-RAR alpha isoforms and detection of minimal residual disease by retrotranscriptase/polymerase chain reaction to predict relapse

Recent data have shown that the PML-RAR alpha fusion gene resulting from translocation t(15;17) is a highly reliable molecular marker of acute promyelocytic leukemia (APL). In this study performed on 97 Chinese patients with APL, the retrotranscriptase/polymerase chain reaction (RT/PCR) was used to evaluate the clinical relevance of the long (L) or short (S) PML-RAR alpha fusion mRNA isoforms and to study minimal residual disease during clinical remission (CR). There were more early deaths during the all-trans retinoic acid (ATRA) induction treatment and more relapses within 2 years of CR in the S-type (6 of 19 cases) than in the L-type group (2 of 33 cases) (P < .025). Among 12 cases analyzed before and after the ATRA-induced CR, 9 cases (75%) showed positive RT/PCR, whereas only 3 cases showed a negative result, justifying the need for chemotherapy after ATRA-induced CR. Eleven of 62 APL patients in CR, after ATRA-induced CR and chemotherapy consolidation (follow-up, from 3 to 72 months), showed positive RT/PCR. Five of them relapsed within 1 to 6 months after the positive test; one converted to negative after further chemotherapy; and 5 remained in CR status without further PCR data. However, the latter 5 cases all received further intensive consolidation therapy after the PCR positivity. These results show that a positive RT/PCR of PML-RAR alpha is a sensitive predictor of relapse in APL.

Linkage analysis of fifty-seven microsatellite loci to bipolar disorder

The authors' goal was to screen for genetic linkage with highly informative deoxyribonucleic acid (DNA) microsatellite markers on a series of moderately sized North American bipolar disorder (BP) pedigrees. These BP pedigrees were genotyped with 57 short tandem-repeat polymorphic systems (microsatellites) that were enzymatically amplified from genomic DNA. We did not find significant evidence for genetic linkage. We found isolated LOD scores greater than 2 on chromosome 1 at two loci in individual pedigrees. Simulation studies for multiple analyses under the assumptions of linkage and nonlinkage were performed. The simulations show that LOD scores greater than 2 could be expected even when linkage is absent. Significance levels need to be considered carefully in systematic linkage studies.

Change of thyroid function in 50 patients with aplastic anemia

The serum thyroid hormones were measured in 50 patients with aplastic anemia (AA). Serum T3 and T4 levels were significantly lower, especially in the elderly and in those in chronic AA, while they were normal in acute AA. There was no obvious difference with thyroid-stimulating hormone (TSH). It was suggested that the result may be caused by euthyroid sick syndrome, a protective adaptation that helps in classifying and evaluating the prognosis of the disease.

Role of amygdaloid nucleus in the correlation between the heart and the acupoint neiguan in rabbits

Amygdaloid nucleus (AMYG) could converge and integrate the signals from electroacupuncture (EA) at Neiguan (P 6) and acute myocardial ischemia (AMI) in rabbits. And EA could regulate the changes in the discharge of single units in AMYG caused by AMI, that is, EA inhibited the increased frequency, and reversed the decreased frequency. This suggested that AMYG is an important link in correlation between the heart and the acupoint Neiguan, providing an experimental basis for the Theory of Channel--Viscera Correlation.

Noise-reduced prostatic MR imaging. Work in progress

Measurement-dependent filtering, a nonlinear noise-reduction technique, was used to improve the signal-to-noise ratio of in vivo T2-weighted magnetic resonance images of the prostate gland. In both normal and abnormal prostates, the technique considerably reduced noise in T2-weighted images. The technique may provide more accurate depiction of regions of benign prostatic hyperplasia and carcinoma in the prostate.

Four categories of gamma-globin gene triplications: DNA sequence comparison of low G gamma and high G gamma triplications

The human fetal gamma chains are produced by closely linked G gamma and A gamma genes, and unequal crossing over between them leads to gamma gene deletions and triplications. Nine gamma gene triplications from seven ethnic groups were analyzed for G gamma and hemoglobin F (Hb F) values of heterozygotes and for the presence of polymorphic XmnI restriction sites 5' to the gamma genes. Four categories of triplication were found: I had low G gamma and low Hb F values and lacked XmnI sites 5' to the three gamma genes [---]. II had high G gamma and slightly elevated Hb F values but was also [---]. III was similar to II, except that XmnI was [+--]. IV had very high G gamma and slightly elevated Hb F values, and XmnI was [++-]. One case each of triplications I and IV were cloned into Charon 35. For both, the two 5' gamma gene code for G gamma chain, while the 3' gamma gene codes for A gamma chain. DNA sequencing showed that the unequal crossover occurred between 472 and 398 base pairs (bp) 5' to the gamma gene Cap sites (-472 and -398) for the type IV triplication and between -271 and codon 136 for the type I triplication. In addition, type I had a 4-bp deletion of AGCA from -225 to -222. The high G gamma values of the type IV triplication are explained by its -G gamma-G gamma-A gamma-gene arrangement and the XmnI sites 5' to the G gamma genes. We hypothesize that the low G gamma value of the type I triplication, which is also -G gamma-G gamma-A gamma-, is due to inactivation of the middle G gamma gene by the AGCA deletion at -225 to -222.

Least squares approach in measurement-dependent filtering for selective medical images

An image-processing method called measurement-dependent filtering has been introduced to improve the SNR (signal-to-noise ratio) of selective images produced by various medical imaging systems. The basic algorithm involves the combination of the low-frequency information of the selective image with the high-frequency information of a nonselective image. A spatially variant control function modulates the amount of high frequency to be added at each point. A least-mean-square (LMS) control function formed from two basis images, namely the high-passed versions of the nonselective image (M(b)) and the selective image (S(b)), is introduced. The original algorithm is now viewed as a two-stage filtering method, including the low-pass filtering noise reduction and least squares filtering for the edge restoration. An appropriate linear transformation is used to convert the original basis images M(b) and S(b) into a new pair with orthogonal noise. This allows the implementation of the LMS and control function with practically obtainable a priori knowledge.