La incontinencia de orina post-prostatectomía radical / Urinary incontinence post-radical prostatectomy

La incontinencia de orina post-prosatectomía radical es una complicacion que se manifiesta en el 0,5 al 11 por ciento de los casos. Su frecuencia ha ido disminuyendo a medida que se fueron perfeccionando las tecnicas quirurgicas. Se presenta nuestra experiencia en 85 prostatectomias radicales realizadas desde 1988 hasta 1999 evaluando los casos de incontinencia de orina producidos, su relación con el estadío clínico, tecnica quirurgica, edad del paciente y tipo de anastomosis. Se describen los procedimientos llevados a cabo para su resolución. Se realiza un repaso de la anatomía y fisiología del mecanismo de la continencia, la fisiopatología de la I.O. post-prostatectomía radical, los factores que aumentan la incidencia de I.O. post-prostatectomía radical y las variantes de tratamiento. Se efectúa una comparación entre los datos recogidos en la bibliografía internacional y nuestra experiencia(AU)

La incontinencia de orina post-prostatectomía radical / Urinary incontinence post-radical prostatectomy

La incontinencia de orina post-prosatectomía radical es una complicacion que se manifiesta en el 0,5 al 11 por ciento de los casos. Su frecuencia ha ido disminuyendo a medida que se fueron perfeccionando las tecnicas quirurgicas. Se presenta nuestra experiencia en 85 prostatectomias radicales realizadas desde 1988 hasta 1999 evaluando los casos de incontinencia de orina producidos, su relación con el estadío clínico, tecnica quirurgica, edad del paciente y tipo de anastomosis. Se describen los procedimientos llevados a cabo para su resolución. Se realiza un repaso de la anatomía y fisiología del mecanismo de la continencia, la fisiopatología de la I.O. post-prostatectomía radical, los factores que aumentan la incidencia de I.O. post-prostatectomía radical y las variantes de tratamiento. Se efectúa una comparación entre los datos recogidos en la bibliografía internacional y nuestra experiencia

Malanoma maligno de pene / malignant melanoma of the penis

Se presenta aquí un paciente de 62 años de sexo masculino con diágnostico de melanoma maligno de pene. Se realizó tratamiento quirúrgico mediante penectomía parcial. El melanoma maligno de pene es una lesión de comportamiento agresivo y presentación poco frecuente. La base del tratamiento es quirúrgica, si bien esta opción no se halla estandarizada. La radioterapia y la quimioterapia actúan como adyuvantes. El pronóstico es pobre y el diagnóstico temprano es el único factor de mejora en los rangos de supervivencia(AU)

Malanoma maligno de pene / malignant melanoma of the penis

Se presenta aquí un paciente de 62 años de sexo masculino con diágnostico de melanoma maligno de pene. Se realizó tratamiento quirúrgico mediante penectomía parcial. El melanoma maligno de pene es una lesión de comportamiento agresivo y presentación poco frecuente. La base del tratamiento es quirúrgica, si bien esta opción no se halla estandarizada. La radioterapia y la quimioterapia actúan como adyuvantes. El pronóstico es pobre y el diagnóstico temprano es el único factor de mejora en los rangos de supervivencia

Nucleic acid in situ probing. Hybridization to human chromosomes of an alkaline phosphatase labeled centromeric probe.

The main principles that underly the use of nucleic acid probes for in situ hybridization are summarized. These include probe design, target preparation, hybridization formats and conditions, and signal generating systems. These principles underly the specific protocol that is described, namely the use of an akaline phosphatase-labeled cloned sequence of the alphoid repeated DNA family as a centomere probe for human chromosomes.

Gene-specific modulation of RNA synthesis and degradation by extremely low frequency electromagnetic fields.

Pulse-labeling studies from our laboratory and others have shown that extremely low frequency (ELF) electromagnetic fields can produce a transient increase in gene transcription. In this study, the synthesis, degradation and processing, and steady state levels of specific RNA species during exposure to ELF radiation were determined in human leukemia HL-60 cells. The overall steady state RNA levels, assessed by continuous and equilibrium labeling with 3H-uridine, were not affected by ELF exposure. Northern blot analysis using probes specific for c-myc, beta-actin, and 45S ribosomal RNA gene products revealed that ELF did not alter the steady state levels of these RNAs. Examination of gene-specific transcription by a novel nuclease protection assay revealed that while ELF did not substantially alter the transcription rates for c-myc and beta-actin, transcription of the 45S ribosomal RNA gene was increased by 40-50%. To explain the observed increase in the synthesis of 45S ribosomal RNA without an associated increase in its steady state level, the degradation and processing of the ribosomal gene transcript in the presence and absence of an ELF field were followed by pulse-chase 3H-uridine labeling. This revealed that ELF radiation accelerated both the processing and degradation of the ribosomal RNA transcript. During ELF exposure, the half-life of the 45S ribosomal RNA was decreased from 115 min. to 85 min. These results show that ELF can selectively affect RNA levels by modulating either the transcription rate and/or RNA post-transcriptional processing and turnover.

Microwave exposure alters the expression of 2-5A-dependent RNase.

The effects of 2.45-GHz continuous-wave microwaves (SAR = 130 mW/g) on the expression of the interferon-regulated enzymes 2'-5'-oligoadenylate (2-5A) synthetase(s) and 2-5A-dependent endoribonuclease (RNase L) were studied in murine L929 cells. Cells growing as monolayers were removed from the substratum and placed in suspension culture for a 4-h sham or microwave exposure. The cells were returned to monolayer growth for 18 h, and then harvested and assayed to determine the amount of RNase L protein (via [32P]2-5A binding) and the specific activities of RNase L and 2-5A synthetase. Binding of radioactive 2-5A to RNase L for sham- and microwave-exposed samples was 14.5 and 36.4% above control, respectively (the microwave-exposed bound 19.0% more probe than the sham-exposed). The increases in 2-5A binding were accompanied by corresponding elevations of RNase L specific activity. In contrast, sham or microwave irradiation produced no alterations in 2-5A synthetase specific activity. No detectable differences were noted in the postexposure cell viability, plating efficiency, or proliferation rate. Also, there were no detectable differences in cell viability or plating efficiency between controls and cultures irradiated for 2 h when the temperature was simultaneously increased to above normal physiological limits (39 to 45 degrees C). The SAR (130 mW/g) and the power density (95 mW/cm2) used for the greater part of this study were nearly 20 times higher than the ANSI limit of 8 mW/g and 5 mW/cm2 for any 1 g of exposed human tissue.

Delineation of electric and magnetic field effects of extremely low frequency electromagnetic radiation on transcription.

The relative effects of the electric and magnetic field components of extremely low frequency electromagnetic radiation (ELF) on transcription were examined in human leukemia HL-60 cells. Delineation of the individual field contributions was achieved by irradiating cells in separate concentric compartments of a culture dish within a solenoid chamber. This exposure system produced a homogeneous magnetic field with a coincident electric field whose strength varied directly with distance from the center of the culture dish. Irradiation of HL-60 cells with sine wave ELF at 60 Hz and a field strength of 10 Gauss produced a transient increase in the transcriptional rates which reached a maximum of 50-60% enhancement at 30-120 minutes of irradiation and declined to near basal levels by 18 hours. Comparison of transcription responses to ELF of cells in different concentric compartments revealed that the transcriptional effects were primarily the result of the electric field component with little or no contribution from the magnetic field.

Differential modulation of human chorionic gonadotropin production by methotrexate in normal and malignant placental cultures and its increase by dibutyryl cyclic adenosine monophosphate and/or actinomycin D in normal cultures.

The influence of methotrexate (MTX), dibutyryl cyclic AMP, and actinomycin D on production of human chorionic gonadotropin (HCG) in normal first trimester human placental organ cultures was compared. Actinomycin D (10(-8) to 10(-6) M) elevated HCG production by as much as 3.5-fold in normal placenta, and a 2-fold increase in HCG levels was obtained by treatment with dibutyryl cyclic AMP (1 mM) and theophylline (1 mM). The combination of dibutyryl cyclic AMP (1 mM) plus theophylline (1 mM) and actinomycin D (10(-8) M) additively enhanced HCG production by 4.5-fold. In contrast, HCG levels in normal placental organ cultures were unaffected by MTX (10(-8) to 10(-5) M) despite several differing treatment regimens. The JAr line of human choriocarcinoma cells, on the other hand, exhibited an 8-fold increase in HCG levels following MTX exposure (10(-7) M). Incorporation of selected radiolabeled precursors of the de novo and salvage pathways of DNA synthesis was evaluated to assess potential metabolic alterations underlying the differential HCG response of these cultures to MTX. Deoxyuridine incorporation into DNA was decreased similarly in both normal and malignant placenta following MTX exposure. However, deoxycytidine incorporation was inhibited by MTX in normal placental cultures but was elevated by as much as 4-fold in JAr cultures exposed to MTX. Thymidine incorporation into DNA was increased in both groups in the presence of MTX; however, thymidine incorporation was more profoundly stimulated (5-fold) in normal placenta than in JAr cultures (2.5-fold). These data indicate dissimilar utilization of the de novo and salvage pathways of DNA synthesis by these cultures which may explain their differential responsiveness to MTX.

The function of gamma-glutamyl transpeptidase as a determinant in cell sensitivity to azaserine toxicity.

The enzyme gamma-glutamyl transpeptidase (GGT) is characteristically present at high levels in mammalian cells that are vulnerable in vivo to the selectively toxic and carcinogenic effects of the naturally occurring diazo amino acid L-azaserine. The possible role of GGT as a determinant of cellular sensitivity to azaserine toxicity was investigated. No correlation was found between GGT activity and the abilities of different cell lines or GGT-deficient cell strains of TuWi, a human nephroblastoma-derived line high in GGT, to accumulate azaserine. However, the thiols glutathione and cysteine were found to inhibit the toxicity of azaserine in cultures of TuWi. In addition, maleate lowered both intracellular and extracellular glutathione levels and enhanced sensitivity of TuWi cells to azaserine, while serine-borate, a potent inhibitor of GGT, increased extracellular glutathione levels and inhibited azaserine toxicity. Since extracellular glutathione accumulation, which may reflect the rate of cellular glutathione turnover, is increased in cultures of azaserine-resistant, GGT-deficient strains of TuWi, we propose that GGT enhances cellular sensitivity to azaserine primarily by increasing the rate of glutathione turnover, thus removing the glutathione from detoxification pathways.

The LD50 test and in vitro toxicology strategies.

In order for in vitro alternatives for acute toxicity testing to emerge, it will be necessary to stage a clearly-defined strategy. The strategy, with its intermediate objectives and proximal decision points, could serve as the basis for validation of the in vitro tests to be used as components of a test battery for assessment of general cytotoxicity and for the evaluation of impairment of differentiated function. An approach for the evaluation of potential neurotoxic agents is presented and could serve as a model for the evaluation of potential ocular, hepatic, and other toxins.

Differential modulation of human chorionic gonadotropin secretion by epidermal growth factor in normal and malignant placental cultures.

The ability of epidermal growth factor (EGF) to modulate the secretion of human chorionic gonadotropin (hCG) in both normal and malignant placental cells was compared. Receptors for EGF were present on the JAr line of choriocarcinoma cells and were localized to the trophoblast cells of normal placental organ cultures as detected by immunofluorescence. Despite the presence of EGF receptors, the normal placenta did not respond to EGF by significantly increasing its levels of hCG production. The JAr line of choriocarcinoma exhibited a 2-fold increase in hCG secretion after the addition of EGF. EGF stimulated growth in the JAr cells, as measured by the protein content of the cultures, but did not elevate the incorporation of [methyl-3H]thymidine in either the JAr cells or placental organ cultures.

The interface of toxicology and tissue culture and reflections on the carnation test.

The convergence of an imperative for expanded testing of chemicals before they are released into the environment and the maturation of tissue culture as an important tool for biomedical research, has led to the development of in vitro methods for toxicological evaluation. Of the several facets of the interface -- screening, mechanisms, personnel monitoring, and risk assessment -- screening has the broadest interface. The success which has been achieved to date stems from a recognition of the limitations as well as the attributes of in vitro research, extensive validation of specific tests (especially for mutagenesis and carcinogenesis), and the use of test batteries rather than single tests.