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Biomedical subjects

R S Verma

Publications and source records attributed to R S Verma.

At least 127 records · Page 7Linked to original sources
PubMed1992

Disappearance of a highly unusual clone, 46,XY,del(7)(p12),t(9;22)(q34;q11) in chronic myeloid leukemia after treatment with recombinant interferon and cytosine arabinoside.

A patient with the typical features of the stable phase of chronic myeloid leukemia (CML) displayed two karyotypically related subclones. In addition to the t(9;22), cells from one clone contained a deletion of the short arm of chromosome 7, del(7)(p12), [46,XY,del(7)(p12),t(9;22)(q34;q11)]; the other contained only the standard translocation [46,XY,t(9;22)(q34;q11)]. Cells with a deletion of the short arm of chromosome 7 at band p12 as the only additional abnormality have not been observed previously in CML. Conventional chemotherapy with hydroxyurea and then with recombinant interferon-alpha (rIFN-alpha) did not reduce the population of either subclone. However, after treatment with a combination of rIFN-alpha and low-dose cytosine arabinoside (LoDac) continuously infused subcutaneously (s.c.), cells from the clone with the deleted chromosome 7 disappeared and normal metaphases were demonstrable.

Adult↗
PubMed1992

Localization of the gene coding for ventricular myosin regulatory light chain (MYL2) to human chromosome 12q23-q24.3.

Human myosin light chain-2 (MYL2) is an important protein involved in the regulation of myosin ATPase activity in smooth muscle. In cardiac muscle, the precise role of MYL2 is not well understood; however, an increase in ventricular MYL2 is observed during myocardial hypertrophy in cardiac patients with valve stenosis. The chromosomal location of the gene coding for MYL2 was identified using a cloned cDNA for human MYL2. Southern blot analysis of DNA from a human/rodent somatic cell hybrid mapping panel showed that the BamHI fragment that hybridized with this cDNA probe was concordant with chromosome 12. The 768-bp cDNA was hybridized to human metaphase chromosomes. The results revealed a significant clustering of silver grains over chromosome 12 bands q23-q24.3, indicating that the gene coding for MYL2 is located in this region.

Cardiomegaly↗
PubMed1992

Variations in alphoid DNA sequences escape detection of aneuploidy at interphase by FISH technique.

The advent of a new staining technique, termed fluorescence in situ hybridization (FISH), allows the rapid identification of the genomic constitution of an individual with aneuploidy even in interphase nuclei through the use of a series of chromosome-specific DNA probes, an approach termed "interphase cytogenetics." However, alphoid DNA sequences of every centromere are polymorphic (heteromorphic), and the number of targeted sequences may be below the detection level of a specific DNA probe, thus escaping detection and resulting in the imprecise identification of the chromosomal constitution at interphase. The limitations associated with the FISH technique have dire consequences which are emphasized here with an example in which the presence of an additional chromosome 21 in two siblings born consecutively with trisomy 21 (Down syndrome) was not detected by "interphase cytogenetics." The copy number of alphoid DNA sequences of one of the paternal chromosomes 21 was low and resulted in discordance between domain numbers at interphase and actual chromosome numbers at metaphase in both children. This is an isolated incident that could have led to a misdiagnosis if FISH were the only test employed. Although the advantages of this technology are undeniably enormous, the present finding has made it apparent that precise standards and reliability of the procedure must be established prior to its routine application.

DNA Probes↗
PubMed1992

Deciphering the fluorescent variability of human genomic heterochromatin by DA/DAPI technique.

A number of selective staining techniques have been utilized to decipher the variability of pericentromeric heterochromatin. One such technique is called DA/DAPI and it is believed to be stain specific. However, we demonstrate otherwise and suggest that pericentromeric regions of all human chromosomes stain positive by DA/DAPI-technique. It must be emphasized that the incidence of DA/DAPI positive stained chromosomes, other than 1, 9, 15, 16 and Y, is a rare occurrence and only a small portion of the pericentromeric region is DA/DAPI positive, as reported here using 50 normal individuals.

Distamycins↗
PubMed1992

The interstitial deletion of bands q33-35 of long arm of chromosome 7: a review with a new case report.

Interstitial or terminal deletion resulting in partial monosomy of various segments of the long arm of chromosome 7 was first recorded over two decades ago. Since then, a number of reports have correlated the severity of clinical manifestations with the length of the deletion involved. However, difficulty remains in defining a so-called "distinct syndrome". We present a new case with the shortest interstitial deletion of the long arm of chromosome 7 bands q33-35, i.e. 46,XX,del(7)(pter----q33::q35----qter). A 4-year-old black female was referred for cytogenetic evaluation due to neurodevelopmental delay. Pertinent physical examination at birth was cleft lip and cleft palate which required corrective surgery. At 2 years of age, a myringotomy tube was inserted for repeated ear infection and a hearing aid was required for conductive deafness. Neurological examination revealed poor eye contact, and severe mental and motor retardation. We reviewed 21 cases of a partial interstitial deletion of varied segments of the long arm of chromosome 7, but we were unable to establish a definite relationship with the deletion of various 7q segments with any specific clinical manifestations.

Adult↗
PubMed1992

Pericentric inversion of chromosome 7 (inv(7) (p22q11.2)) and ring chromosome 8 (r(8) (p23q24.3)) in a girl with minor anomalies.

A 13 year old girl was referred with congenital microcephaly, developmental delay, a prominent nose, highly arched palate, and an apparently low set left ear. She was found to have a pericentric inversion of one chromosome 7 and a ring chromosome 8, 46,XX,inv(7) (pter----p22::q11.23----p22::q11.23----qter), r(8) (p23q24.3). The concurrence of these two abnormalities is a rare event and has not been reported previously.

Abnormalities, Multiple↗
PubMed1992

Tandem duplication of the terminal band of the long arm of chromosome 7 (dir dup (7)(q36----qter)).

We report on a new case of a single band duplication of the long arm of chromosome 7, dir dup (7)(q36----qter). The major manifestations are developmental delay (particularly speech), frontal bossing, macrocrania, and constant drooling. When compared with other cases involving a 7q duplication of various segments, our patient has a few minor anomalies. This case illustrates the genotype/phenotype correlation in a child with a single band duplication which has resulted in duplication of 7q36----qter. A tabulation of reported cases with duplication of various segments of 7q is provided, which may serve as an aid for clinicians.

Abnormalities, Multiple↗
PubMed1992

New dysmorphic features in Rubinstein-Taybi syndrome.

We report a new case of Rubinstein-Taybi syndrome with a hypoplastic right kidney, persistent pulmonary hypertension, and mitral valve regurgitation. Other pertinent features included broad thumbs, broad big toes, syndactyly of the third and fourth fingers bilaterally, beaked nose, broad columella of the nose, patent ductus arteriosus, and motor and mental retardation. The testes were descended. The 3 month old patient had delayed motor and mental development corresponding to a 1 month old infant.

Humans↗
PubMed1992

Cytogenetic evidence for extramedullary blast crisis with t(8;13)(q11;p11) in chronic myelomonocytic leukemia.

A 27-year-old male developed massive generalized lymphadenopathy with chronic myelomonocytic leukemia (CMML) presenting as extramedullary blast crisis mimicking a lymphocytic lymphoma. On presentation, a consistent chromosomal abnormality involving chromosomes 8 and 13, i.e. 46,XY,t(8;13) (q11;p11), was present in lymph node tissue, bone marrow and unstimulated peripheral blood. The appearance of trisomy 21 in addition to the presence of the original cytogenetic abnormality is simply regarded as clonal evolution, i.e. 47,XY,t(8;13)(q11;p11),+21. The importance of the cytogenetics lies in finding the same abnormality in bone marrow and lymph node, adding evidence that the immunologically similar cells in the two sites have arisen from a common progenitor cell. To our knowledge, this novel chromosomal abnormality has not been reported in association with a unique case.

Adult↗
PubMed1992

Prenatal cytogenetic diagnosis of 1,400 consecutive amniocenteses.

We report on the incidence of chromosomal abnormalities in 1,400 amniocenteses. Thirty-one cases (2.21%) were found to have various types of chromosomal abnormality. The majority of abnormal cases (54.84%) were trisomies. All individuals with trisomic fetuses chose to terminate the pregnancy with the exception of one who gave birth to a Down's syndrome child. However, fetuses with apparently balanced translocations were phenotypically normal at birth.

Amniocentesis↗
PubMed1992

Molecular characterization of the secondary constriction region (qh) of human chromosome 9 with pericentric inversion.

Pericentric inversion of the secondary constriction region (qh) of human chromosome 9 is a frequent occurrence. This structural alteration is regarded as a normal familial variant, termed heteromorphism, and is inherited in a Mendelian fashion without any apparent phenotypic consequences. We characterized the qh region of chromosome 9 from five individuals using a series of molecular cytogenetic techniques. Four out of the five individuals have an additional area composed of alphoid DNA sequences on the inverted chromosome 9 while one case was found to have an apparently intact alphoid DNA sequence. Although the direct function(s) of alphoid DNA sequences remain unclear, the centromeric breakage involving these sequences in inverted chromosome 9 raises a series of questions pertaining to the monocentric, dicentric and pseudodicentric nature of pericentric inversions. Nevertheless, these findings have prompted us to suggest that the structural organization of alphoid DNA sequences of the centromeric region of chromosome 9 are apparently "breakage prone" and may be associated with a higher incidence of pericentric inversions. Furthermore, the hierarchical organization of various satellite DNA families (alpha-satellite, beta-satellite and satellite III) within the primary and secondary constriction regions of chromosomes 9 are elucidated here.

Adult↗
PubMed1992

The T cell receptor gene and its association with human diseases.

The genetic organization and protein structure of the T cell receptor (TCR)/CD3 complex are currently under investigation, and recent work has provided information about its assembly, expression and function. This article reviews what is currently known about the structure and assembly of the TCR/CD3 complex. The TCR chains are members of the immunoglobulin gene superfamily and are generated by combinatorial associations of V, J, D, and C genes. The presence of certain gene rearrangements within these chains has been associated with lymphoproliferative disorders, autoimmune disease and immunodeficiencies. TCR rearrangements can be useful in the diagnosis of lymphoproliferative disorders and in the identification of patients who will subsequently relapse, once in remission. With respect to autoimmune disease, the possibility now exists of immunotherapy with TCR designer polypeptides to prevent disease. In patients with primary immunodeficiencies secondary to defects in expression of the TCR, the possibility of somatic gene therapy now exists. As more information unfolds about the role that TCR gene rearrangements have in various diseases, new insights are gained into better diagnosis and treatment.

Autoimmune Diseases↗
PubMed1992

An apparent balanced translocation [t(9;11)(p21.2;p14.2)] in a neonate with dysmorphic features.

The role of so called balanced translocations in human morphogenesis remains puzzling. An eleven month old hispanic female was referred for neurological evaluation. The major dysmorphic features include: epicanthal folds, flat nasal bridge, small mouth, micrognathia, low set ears and cleft-palate. The cytogenetic findings by multiple banding techniques revealed an apparent balanced translocation involving chromosomes 9p and 11p i.e. 46,XX,t(9;11)(p21.2;p14.2) which, according to the authors, has not been previously reported.

Abnormalities, Multiple↗
PubMed1992

A new case of monosomy for 17q25----qter due to a maternal translocation [t(3;17)(p12;q24)].

An 18-month-old girl was found to have monosomy for 17q25----qter which resulted from an unequal crossing-over in the mother carrying an apparently balanced translocation 46, XX, t(3;17) (p12;q24). Clinical features of the proband included: cleft palate, micrognathia and glossoptosis. It seems to be the first reported case where a single band deletion in the long arm of chromosome 17 has ever been noted.

Chromosomes, Human, Pair 17↗
PubMed1991

Complex chromosomal abnormalities in a patient with refractory anemia with excess blasts (RAEB).

We report a new case of refractory anemia with excess blasts (RAEB) having complex chromosomal abnormalities. The 5q- associated with RAEB and other preleukemic syndromes was present in 100% of the cells; however, 60% of the cells had a highly unusual derivative chromosome involving the short arm of chromosome 1 and the long arm of chromosome 5, i.e., t(1;5)(p36;q14). Although the patient presented with highly complex chromosomal abnormalities, his initial clinical presentation was that of typical refractory anemia with excess blasts. Shortly after diagnosis (7 months), the patient developed acute leukemia.

Anemia, Refractory, with Excess of Blasts↗
PubMed1991

Kinetic analysis, isolation, and characterization of hydrophilic folate-binding proteins released from chorionic villi cultured under serum-free conditions.

Full term placental chorionic villi cultured for 7 days in serum-free medium released hydrophilic folate-binding proteins (S-FBP(PCM) into the conditioned medium; in contrast, hydrophobic FBPs were the only form recovered from chorionic villi. Kinetic studies revealed that (i) S-FBP(PCM) was maximally released by the 3rd day, and this was associated with a proportionate decrease in hydrophobic FBPs; (ii) although cycloheximide inhibited de novo synthesis of [35S]methionine-labeled hydrophobic FBPs and S-FBP(PCM) by greater than 90%, unlabeled net S-FBP(PCM) release was only inhibited by 50%; (iii) EDTA markedly inhibited release of S-FBP(PCM) which was accompanied by a proportionate increase in hydrophobic FBPs; (iv) EDTA effects were completely reversed by 5-fold molar excesses of Mg2+ which led to a 50-fold greater release of S-FBP(PCM) compared to EDTA alone; (v) whereas Mg2+ alone stimulated S-FBP(PCM) release 4-fold greater than basal conditions, addition of cycloheximide to Mg2+ suppressed (by 4-fold) the expected increase observed with Mg2+ alone. Biochemical analyses of isolated S-FBP(PCM) revealed similarities to hydrophobic FBPs with respect to the ligand-binding domain and epitopes but differed in detergent-binding characteristics; furthermore, amino acid and carbohydrate analysis revealed a lower Mr = 25,500 with 12% carbohydrate. Based on kinetic analysis of S-FBP(PCM) release from chorionic villi-associated hydrophobic FBPs as well as structural analysis of S-FBP(PCM), these data continue to support the hypothesis that (a) a significant amount of maternal and probably fetal serum hydrophilic FBPs originate from placental hydrophobic FBPs, and (b) the endogenous hydrophobic FBP-directed Mg(2+)-dependent placental protease plays a major role in their release.

Carrier Proteins↗
PubMed1991

Inversion-duplication of bands q13----q21 of human chromosome 9.

Structural abnormalities involving heterochromatic regions of the human genome are difficult to characterize because these segments are G-band negative by GTG technique, a routinely used procedure in clinical cytogenetic laboratories. Chromosome abnormalities of such cases have gone undetected or were incorrectly characterized because these regions are so-called heteromorphisms or variants. Consequently, much anxiety has been aroused by the confusion between a chromosome abnormality and a normal heteromorphic variant. We report the first documented case with a so-called highly unusual h region of chromosome 9 which is not a variation but a structural rearrangement involving a paracentric inversion and a duplication. The major clinical features were psychomotor retardation, microcephaly, narrow palpebral fissures, renal and genital anomalies, vertebral anomalies, protruding tongue, and learning and behavioral problems. A concise review of variable duplicated segments of 9q is also provided.

Abnormalities, Multiple↗