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Biomedical subjects

M Lieber

Publications and source records attributed to M Lieber.

10 recordsLinked to original sources
PubMed1991

Incidence and outcome of surgery for benign prostatic hyperplasia among residents of Rochester, Minnesota: 1980-87. A population-based study.

The incidence and outcome of surgery for benign prostatic hyperplasia (BPH) was studied in Rochester, Minnesota, during the period 1980-1987. Three hundred thirty Rochester men without a diagnosis of prostate or bladder cancer underwent prostatectomy for BPH for the first time. Mean and median ages were both seventy (range: 46-95). The incidence of initial prostatectomy for BPH among men forty-five years of age and older age-adjusted to the 1980 U.S. white male population was 642 cases per 100,000 persons per year (py). Among the 330 men undergoing initial prostatectomy for BPH, 14 (4.2%) had serious intraoperative complications, 32 (9.7%) were rehospitalized for urologic complications within thirty days of surgery, and 13 (3.9%) had other serious complications within thirty days after surgery, including 1 death (surgical mortality 0.3%). Forty-five patients (14%) required blood transfusions within thirty days of surgery. The likelihood of reoperation within six years of the initial surgery was 15.1 percent (95% CI 9.7, 20.6). Short- and long-term postoperative mortality was not statistically significantly different than expected based on age- and sex-specific mortality statistics for Rochester, Minnesota.

Aged↗
PubMed1991

Benign prostatic hyperplasia: a population-based study.

To evaluate the incidence and outcome of initial surgery for benign prostatic hyperplasia (BPH) and to clarify the natural occurrence and progression of such urologic diseases, two studies have been conducted in a free-living population in Rochester, MN. The first followed 330 men who had not been diagnosed with prostate or bladder cancer at the time of prostatectomy. All surgery subjects were area residents and between 46 and 95 years of age (mean age 70 years). Among the operated subjects, 14 (4.2%) had serious intraoperative complications, 32 (9.7%) were rehospitalized for urologic complications within 30 days after surgery, and 13 (3.9%) experienced other serious complications in that same time period. Blood transfusions within 30 days of surgery were necessary in 45 patients (14%). The risk of reoperation within 6 years of the initial surgery was calculated at 15.1% (95% CI: 9.7, 20.6). On the basis of age- and sex-specific mortality statistics for Rochester, short- and long-term postoperative mortality was not statistically significantly different from that expected. Results of the second study are not yet available. This population-based evaluation of the natural history of urologic disease is expected to clarify the relative utility of various treatment options and provide a useful perspective on the management of BPH.

Aged↗
PubMed1990

Mutagenesis as viewed from another perspective.

Mutation has generally been considered a random process, not directed. Thus, a mechanism allowing for adaptively responsive mutagenesis has conceptually been precluded. However, an adaptively directed mutagenesis in response to environmental stress can be based upon genetic mutator systems. Such systems, known for years, have been seen as exceptional and not considered in terms of an adaptively responsive mutagenesis. Environmental stress which invokes this type of mutagenesis can thus be regarded as mutagenic itself, and our concept of what is mutagenic must therefore be broadened. Relevant matters are also discussed.

Adaptation, Physiological↗
PubMed1989

New developments on the generation of mutations in Escherichia coli lysogens.

Through the lytic process, P1 is a bacteriophage or virion capable at very low frequency of carrying out generalized transduction between strains of Escherichia coli. When P1 is not involved in lytic functions, it exists as a prophage in the form of circular DNA molecule, persisting in an extra-chromosomal or plasmid state, and not integrating into the host chromosome. E. coli carrying such plasmids have been referred to as lysogens. Earlier research dealt with P1 plasmids carrying drug-resistant factors. Up to the present study, P1 plasmids of any type were not known to have any mutagenic effect on the E. coli chromosome (genome), nor was it known that generalized transduction can be associated with mutagenicity. From P1 plasmids carrying a chloramphenicol resistance-factor, mutant plasmids of a particular type were isolated in the present study. P1 plasmids of this type carried a mutant factor which greatly impaired the capacity of phage derived from such plasmids, upon the completion of the lytic cycle, to lysogenize recA E. coli through phage promoted recombination. The plasmid of this mutant type is referred to as P1CMrec, and lysogens carrying such are referred to as P1CMrec lysogens. This paper describes the history of these P1CMrec lysogens and the genetic mutability within the E. coli chromosome of such P1CMrec lysogens, and the relationship of such genetic mutability (instability) to the incorporation of virion-DNA, following the absorption of P1 phage by these lysogens. As illustrated in the paper, a mutagenic effect was generated within the E. coli chromosome of P1CMrec lysogens by means of the P1CMrec plasmid. Furthermore, this mutagenic effect was found to be greatly, non-locally, and uniformly enhanced as a consequence of P1 virion incorporation by, or likely generalized transduction of, such lysogens. More specifically, the plasmid of this mutant type (P1CMrec) is responsible for the creation of a wide range of genetic mutabilities (instabilities) of differing degree within the E. coli genome (not carrying recA), some mutabilities being very high upon extended incubation. The P1CMrec plasmid was also involved in the creation of new mutant genes within the E. coli genome (not carrying recA), some mutabilities being very high upon extended incubation. The P1CMrec plasmid was also involved in the creation of new mutant genes within the E. coli chromosome, some of which manifested high mutability.(ABSTRACT TRUNCATED AT 400 WORDS)

Bacteriophages↗
PubMed1977

Latent adenocarcinoma in renal cysts.

A case is presented in which repeat examination of a benign cyst disclosed a latent adenocarcinoma near the cyst wall. Since statistically there is a greater incidence of tumor associated with cyst and since there is a 90% accuracy rate in the diagnosis of cystic lesions it appears that reinvestigation seems justified in some cases, especially if there is a change in or new development of symptoms.

Adenocarcinoma↗
PubMed1976

A continuous tumor-cell line from a human lung carcinoma with properties of type II alveolar epithelial cells.

The A549 tumor-cell line, initiated from a human alveolar cell carcinoma, has been continuously propagated in vitro for more than 3 years (more than 1,000 cell generations). These cells have a human karyotype and appear to have been derived from a single parent cell. All A549 cells examined by electron microscopy at both early and late passage levels contain multilamellar cytoplasmic inclusion bodies typical of those found in type II alveolar epithelial cells of the lung. At early and late passage levels, the cells synthesize lecithin with a high percentage of disaturated fatty acids utilizing the cytidine diphosphocholine pathway; such a pattern of phospholipid synthesis is expected for cells believed to be responsible for pulmonary surfactant synthesis. The A549 cell line should permit in vitro analysis of human surfactant synthesis and secretion and possibly provide a source of human surfactant for therapeutic intervention in pulmonary disease states characterized by surfactant deficiency.

Adenocarcinoma, Bronchiolo-Alveolar↗
PubMed1975

Establishment of a continuous tumor-cell line (panc-1) from a human carcinoma of the exocrine pancreas.

An epithelioid cell line, started from a human pancreatic carcinoma of ductal cell origin, has been maintained in culture for over 2 years and has been subcultured more than 40 times. The PANC-1 cell line has a doubling time of 52 h and G6PD activity of the slow mobility of B type. Chromosome studies show a modal number of 63 with three distinct marker chromosomes and a small ring chromosome. The malignant nature of the PANC-1 cell line was verified by: (1) the ready growth of PANC-1 cells in soft agar and on top of a fibroblast monolayer; and (2) the formation of a progressively growing anaplastic carcinoma after injection of a nude-athymic mouse with PANC-1 cells.

Carcinoma↗
PubMed1975

Isolation of type-C viruses from the Asian feral mouse Mus musculus molossinus.

N-tropic and xenotropic type-C viruses have been isolated from the wild Asian mouse subspecies M. musculus molossinus. By host range, morphologic and some immunologic criteria these viruses appear closely related to the previously studied murine type-C viruses isolated from highly inbred laboratory strains of mice.

Animals↗