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Biomedical subjects

P Metz

Publications and source records attributed to P Metz.

At least 37 records · Page 2Linked to original sources

Tn916-induced mutations in the hemolysin determinant affecting virulence of Listeria monocytogenes.

A genetic determinant essential for hemolysin production by Listeria monocytogenes has been inactivated by insertion of transposon Tn916 into L. monocytogenes DNA. The transposon was transferred by means of conjugation of a streptomycin-resistant L. monocytogenes recipient strain with Streptococcus faecalis CG110 on membrane filters. Among the tetracycline-resistant transconjugants, mutants were detected which had lost hemolytic activity. When tested in a mouse model, these mutants appeared to have lost the virulence that characterizes the parental strain. An extracellular protein of 58,000 apparent molecular weight was eliminated in the nonhemolytic mutants. In some of the mutants, the decrease in the production of the 58,000-dalton protein was accompanied by the production of a new protein of 49,000 apparent molecular weight. Hemolytic revertants regained the hemolytic phenotype and virulence and produced the extracellular protein that characterizes the recipient strain. Hybridization studies with Tn916 DNA indicated that the transposon is present in EcoRI and HindIII fragments of the nonhemolytic mutants. Single copies of Tn916 were detected in the chromosomal DNA of two of the three nonhemolytic mutants that were studied in detail. In hemolytic, tetracycline-sensitive revertants Tn916 appeared to be completely excised from the chromosome.

DNA Transposable Elements↗

Arteriogenic erectile impotence.

Organic causes of erectile impotence, including penile arterial insufficiency, is far more frequent than previously assumed. The aim of this review (based on the literature and previous works of the author) is to define arteriogenic erectile impotence, and to describe its pathophysiological and clinical features, the diagnostic approach, differential diagnostic aspects and possible treatment of this type of impotence. Erectile impotence is inability to react to relevant sexual stimulation, with a change in pelvic and penile hemodynamics that will increase the pressure in the cavernous bodies thus enabling vaginal intromission without special precautions; as well as inability to maintain this pressure ordinarily until ejaculation occurs. Arteriogenic erectile impotence is erectile impotence caused by insufficient arterial blood supply to the cavernous bodies regardless of the arterial disease or abnormality responsible for the insufficiency. The normal mechanism of erection is not fully understood. Accumulation of blood under pressure in the cavernous body is brought about by dilation of the arteries to the cavernous spaces and closure of the drainage from the cavernous body. The drainage blockade is active and located just inside the tunica albuginea at the origin of the emissary veins. The mechanism is probably related to the smooth muscles of the cavernous body which become relaxed at the start of erection. Furthermore, passive out-flow restriction probably supporting the active closure when the cavernous body is distended. The autonomic nerves regulating the erection come from Th10-L2 and S2-S4 and pass the pelvic plexus. The target organ neurotransmitters are probably vasoactive intestinal polypeptide and catecholamines. Penile arterial insufficiency can be demonstrated by penile blood pressure measurement either as a simple measurement, or, better, as pelvic steal test and hyperemic stress test. Ultrasonic Doppler pulse curve analysis is another way of demonstrating penile arterial insufficiency. Visualization of the arterial disease causing penile arterial insufficiency requires bilateral selective internal iliac arteriography.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗

New operation for "krummerik" (penile curvature).

A corrective operation for penile curvature using plication of the tunica albuginea on the opposite side of the angulation is described. The operation is fast, easy to perform, and complications are rare.

Humans↗

Peyronie's disease and erectile failure.

A total of 20 patients with Peyronie's disease, including 15 with erectile failure and 5 with normal potency, underwent evaluation with dynamic xenon washout and infusion cavernosography. Abnormal drainage from the cavernous body was found in 13 of the 15 patients with erectile failure and in none of the 5 potent patients (p less than 0.01), indicating that this condition seems to be the underlying pathological mechanism leading to erectile impotence in patients with Peyronie's disease.

Adult↗

Epigastrico-cavernous anastomosis in the treatment of arteriogenic impotence.

During the period August 1980--January 1982 nine patients were treated for erectile impotence due to arterial insufficiency in the penis, with epigastrico-cavernous anastomosis. Two patients had no effect of the operation. Two patients developed priapism postoperatively and one of these lost his potency probably because of delayed treatment, while the other remained potent. Of the remaining five patients three lost the regained potency within one year, and two are still potent 21 and 24 months after the operation. It is concluded that the long term results of the epigastrico-cavernous anastomosis is unsatisfactory and that new approaches for revascularization of the cavernous bodies in arteriogenic impotence are required.

Adult↗

Erectile function before and after reconstructive arterial surgery in men with occlusive arterial leg disease.

Erectile impotence is a well-known complication of vascular surgery in the aorto-iliac area. So far the pathogenesis has not quite been understood, but peroperative damage to the autonomous nerves has been suggested. Ninety-eight men with arterial insufficiency in their legs underwent an additional sexual evaluation including penile blood pressure measurement and cystometric examination. The arterial insufficiency necessitated arterial reconstruction involving aorta or the common iliac arteries in 28 patients. When possible, improvement of the penile blood supply was aimed at during the operation, but no nerve-sparing techniques were employed. The seven potent patients remained potent, while nine patients became potent after the operation. The cases remaining impotent after the operation could all be explained considering the arteriography, the operation and the changes in penile blood pressure. The erectile function is related to the condition of the penile blood supply and it may be possible to reduce the rate of postoperative impotence by considering the penile blood supply when planning the operative strategy.

Adult↗

Radioimmunoassay of bile acids in tissue, bile, and urine.

Two commercially available (Abbott Labs.) radioimmunoassays for determination of conjugated cholic acid and sulfoglycolithocholic acid in serum have been modified for bile acid measurements in alcoholic tissue extracts, bile, and urine. The specificity of both radioimmunoassays has been determined with regard to 27 free and conjugated bile acids. After filtration, bile acids can be measured in urine and bile without prior extraction. Tissue is homogenized and the bile acids are extracted into methanol. Urinary excretion by 64 healthy humans was 2.09 (SD 1.09) mumol of conjugated cholic acid and 8.44 (SD 8.03) mumol of sulfated glycolithocholic acid per 24 h. In liver from 10 patients with various noncholestatic liver disease, the mean concentration of conjugated cholic acid was 32.4 (SD 15.9) nmol/g wet weight. In the liver of 27 male Wistar rats, the concentration of conjugated cholic acid was 41.3 (SD 11.7) nmol/g of tissue, of sulfoglycolithocholic acid 5.1 (SD 2.3) nmol/g of tissue.

Adult↗

Use of the rhomboid flap after partial vulvectomy.

Primary closure of vulvar excisions is usually satisfactory in the anterior vulva, where the skin is mobile. In the posterior and posterolateral areas, however, closure often must be accomplished under tension with resulting wound breakdown and scar formation that can be disfiguring and cause dyspareunia. The rhomboid skin flap was described as early as 1946. Initially described for closure of facial defects, the technique has found application in the closure of a variety of traumatic and surgical defects. The authors present eight patients who underwent closure of vulvar defects using single or multiple rhomboid flaps. The applicability of the procedure to vulvar surgery is discussed and the technique is described.

Female↗