Biomedical subjects

A M Patel

Publications and source records attributed to A M Patel.

13 recordsLinked to original sources

PubMed1992

Analysis of prostatic tumor cultures using fluorescence in-situ hybridization (FISH).

Analysis of ten primary prostatic tumor cultures using fluorescence in-situ hybridization (FISH) with pericentromeric probes for chromosomes 7, 8, 10, 16, 17, and 18 revealed aneusomies in nine of these specimens. Classical cytogenetics by G-banding indicated that only four of those same ten specimens had any (but not consistent) clonal abnormalities. This preliminary study suggests that aneusomy is a common event in early-stage prostatic tumors, and also supports the notion that multiple chromosomes are involved. In combination with routine cytogenetic analysis, FISH is thus likely to be a powerful tool in the evaluation of prostatic cancer.

Chromosome Aberrations↗

PubMed1992

RNase E-dependent cleavages in the 5' and 3' regions of the Escherichia coli unc mRNA.

The endonucleolytic processing of the unc mRNA encoding the eight subunits of the Escherichia coli F1F0-ATPase was studied. Northern (RNA) blots of mRNA expressed from a plasmid which contained the 3'-terminal portion of the operon including the uncDC sequences revealed, in addition to the expected 2-kb mRNA, a 0.5-kb RNA species which hybridized to an uncC antisense RNA probe. An uncD antisense RNA probe hybridized to only the 2-kb mRNA, implying that the upstream 1.5-kb fragment is rapidly degraded. The 5' end of the 0.5-kb fragment was determined by primer extension analysis to be 11 bases into the coding region of the uncC gene. In RNase E-deficient strains, the amount of the 0.5-kb product was strongly reduced while the levels of the precursor uncDC transcript remained high. Similar RNase E-dependent processing was found in the chromosomally encoded unc mRNA. As this RNase E-dependent cleavage directly inactivates uncC and appears to leave uncD susceptible to degradation, it seems unlikely to play a role in differential expression of the gene products but may be an important event in unc mRNA degradation. RNase E mutants also showed altered processing of the chromosomally encoded unc mRNA in the uncB region near the 5' end. The expected full-length (7-kb) transcript was recognized when RNA from the RNase E-deficient strain was subjected to Northern blot analysis with uncB- and uncC-specific probes. RNA from strains with functional RNase E lacked the 7-kb transcript but had a 6.2-kb mRNA detectable with the uncC but not the uncB probe. RNase E is therefore implicated in multiple cleavages of the unc mRNA.

Base Sequence↗

PubMed1992

Characterization of 10 marker chromosomes in a prostatic cancer cell line by in situ hybridization.

Marker chromosomes contain potentially valuable information about breakpoints in cancer. However, routine banding procedures, by themselves, provide only limited information about the identity of marker chromosomes. In this study, the use of fluorescence in situ hybridization (FISH) with chromosome-specific centromeric probes and whole-chromosome-specific DNA libraries greatly enhanced the identification of 10 marker chromosomes in the primary prostatic cancer cell line PPC-1. Centromeric probes for chromosomes 1, 2, 3, 4, 10, 12, and 17 and whole-chromosome paint libraries for chromosomes 1, 2, 3, 4, 8, and 12, in conjunction with analysis of G-banded metaphases, allowed the major portion(s) of these 10 PPC-1 marker chromosomes to be defined. The results increase the number of identifiable chromosomal breakpoints in this cell line from 9 to 28 sites.

Centromere↗

PubMed1991

Cytogenetic evaluation of 20 cultured primary prostatic tumors.

We report the cytogenetic evaluation of 20 cultured cell strains derived from primary prostatic adenocarcinomas obtained from radical prostatectomies. The majority of the strains contained cells with only normal male karyotypes (46,XY), but cytogenetically abnormal clonal populations were found in five strains. Two of those strains contained aberrations involving the Y chromosome, one with a -Y and one with a +Y. Three strains (one of which also had the XYY karyotype) exhibited cells with double-minute chromosomes and four strains contained near tetraploid cells.

Adenocarcinoma↗

PubMed1991

Nocturnal nasal ventilation for treatment of patients with hypercapnic respiratory failure.

We reviewed the Mayo Clinic experience with nocturnal nasal ventilation (NNV) and retrospectively assessed the clinical benefits, patient compliance, and complications. NNV had been instituted in 26 patients with daytime hypercapnia and nocturnal hypoventilation due to neuromuscular diseases or chronic obstructive pulmonary disease. After initiation of NNV, 21 of 26 patients continued to use this treatment regularly (81% compliance rate) and considered their life-style improved. In this subset of patients, the arterial partial pressure of carbon dioxide during unassisted breathing decreased from 64 +/- 13 to 51 +/- 7 mm Hg, and the arterial partial pressure of oxygen increased from 58 +/- 12 to 68 +/- 8 mm Hg. No significant change was noted in the forced vital capacity or maximal respiratory pressures. Four of the five patients in whom NNV had been discontinued cited discomfort related to the mask or severity and poor prognosis of the underlying illness as reasons for cessation of treatment. We conclude that NNV is well tolerated by most patients and may improve alveolar ventilation and arterial oxygenation in patients with chronic respiratory failure.

Adolescent↗

PubMed1990

Frequency and pattern of karyotypic abnormalities in human prostate cancer.

The cytogenetic evaluation of 30 cultured primary prostatic cancer specimens obtained during radical prostatectomies of patients with relatively early stage disease is reported. The majority of specimens examined showed a normal male karyotype, 46,XY. Nine samples contained clonally abnormal populations including five specimens which were hyperdiploid (modal range, 65-92 chromosomes), one specimen containing double minute chromosomes, and three containing structural aberrations. Loss of the Y chromosome and a partial trisomy for chromosome 4 was observed in a sample from one patient. Another sample showed a translocation between the long arms of chromosomes 5 and 7. The only tumor obtained from a previously irradiated patient contained no normal cells, a modal chromosome number of 45, loss of chromosomes 2 and Y, and multiple structural rearrangements. The appearance of any clonal cytogenetic abnormality correlated in general with a poorly differentiated state of cancer. A survey of all available previous cytogenetic data on human prostate adenocarcinoma indicated that the loss of chromosomes 1, 2, 5, and Y, the gain of chromosomes 7, 14, 20, and 22, and rearrangements involving chromosome arms 2p, 7q, and 10q are the most common changes observed. This suggests that, although the assignment of a single chromosomal aberration as a marker for early stage prostatic cancer is unlikely, several consistent "hotspots" might be of significance in the etiology of this disease.

Chromosome Aberrations↗

PubMed1990

The Escherichia coli unc transcription terminator enhances expression of uncC, encoding the epsilon subunit of F1-ATPase, from plasmids by stabilizing the transcript.

The effect of the unc transcription terminator on expression of uncC, encoding the epsilon subunit of Escherichia coli F1-ATPase, from plasmids was studied. The cloned sequence in pTK1 included the uncC ribosome binding site, the uncC structural gene, and the unc transcription terminator. The cloned region in pSD37 was similar, but lacked the unc transcription terminator. Transformants carrying pTK1 produced the epsilon subunit of F1-ATPase, encoded by uncC, in 10-fold greater abundance than transformants carrying pSD37. Northern blots revealed similar differences in the steady-state uncC mRNA levels. The half-life of the message transcribed from pTK1 was 90-100 seconds, while that from pSD37 was 25-30 seconds. These studies indicate the importance of message stabilization through features at the 3' end of the transcript in ensuring adequate production of epsilon. We have exploited this stabilization to develop a simple, efficient, and gentle method of purifying the overproduced epsilon subunit.

Blotting, Northern↗

PubMed1989