Biomedical subjects

S Corvin

Publications and source records attributed to S Corvin.

26 records · Page 2Linked to original sources

PubMed1999

Cryptorchidism, open processus vaginalis, and associated hernia: laparoscopic approach to the internal inguinal ring.

OBJECTIVES: A nonpalpable testis was the first indication for laparoscopy in urology. This primarily diagnostic procedure has evolved to complete laparoscopic orchidopexy. An associated inguinal hernia due to an open processus vaginalis is reported in 26% of cryptorchidism cases. Simultaneous laparoscopic orchidopexy and herniorrhaphy are therefore the next logical step. METHODS: Between 1992 and 1998, 61 children underwent laparoscopy for pathology of the internal inguinal ring. In 48 boys the operation was performed for a nonpalpable testis and in 13 boys laparoscopic transection of the processus vaginalis was performed because of clinical hydrocele. RESULTS: In 25 of the 48 cases an intra-abdominal location was found with 18 existing and 7 vanishing testicles. Laparoscopic orchidopexy was performed either as a two-stage Fowler-Stephens technique (n = 6) or as a direct one-stage repair (n = 12). In 6 boys with cryptorchidism a direct inguinal hernia was associated, which received simultaneous laparoscopic herniorrhaphy. In 23 cases of cryptorchidism with an inguinal location of the testis, 3 vanishing testicles were found. In 20 cases with normal testicular vessels, an inguinal exploration followed. In 4 of the hydrocele cases additional herniorrhaphy had to be performed. In all cases the operation could be performed as planned without complications. After orchidopexy all testicles were in the normal position and well perfused as revealed by flow Doppler sonography. All hydroceles disappeared within several days. There was no inguinal hernia recurrence. CONCLUSIONS: Laparoscopic dissection of the internal inguinal ring allows perfect delineation of the anatomic structures and their relationship. Transection of the processus vaginalis can be performed without disturbance of the inguinal canal. Hernias can be closed with essentially the same technique as used in open surgery. Morbidity was minimal in all patients.

Child, Preschool↗

PubMed1998

Videoimaging of prostatic stromal-cell contraction: an in vitro model for studying drug effects.

BACKGROUND: Stromal-cell contractility is known to play an important role in the development of bladder outlet obstruction secondary to benign prostatic hyperplasia (BPH). An in vitro model of single-cell contraction was developed to investigate the effect of alpha1-adrenoceptor agonists and antagonists. METHODS: Human prostatic stromal cells were isolated from prostatectomy and cystoprostatectomy specimens. The cells were cultured in a selective medium supplemented with growth factors and steroid hormones. The culture flasks were coated with a viscous agent to allow cell contraction. Contractions were visualized by means of a cell-culture microscope fitted with a time-lapse video system. For quantitative analysis, the percentage of contracting cells was evaluated. RESULTS: Nineteen percent of the cells were found to contract without stimulation. Following incubation with doxazosin (10 nM, 100 nM, and 1 mM), there was a slight dose-dependent decrease in the number of spontaneously contracting cells, whereas adrenergic stimulation using 10 microM of phenylephrine led to a significant increase in the percentage of contracting cells (55%). Following incubation with 100 nM of doxazosin, the phenylephrine-induced effect was significantly reduced. CONCLUSIONS: This simple in vitro model of cell contraction in the prostate provides a useful means of investigating drug effects on prostatic stromal cells.

Adrenergic alpha-Agonists↗

PubMed1998

Analysis of a mutant androgen receptor offers a treatment modality in a patient with partial androgen insensitivity syndrome.

OBJECTIVES: In male pseudohermaphroditism patients, we have detected androgen receptor (AR) gene mutations as the underlying molecular defect. The properties of these mutant receptors regarding hormone binding and transactivation were characterized. In a newborn patient with partial androgen insensitivity syndrome caused by an AR gene point mutation, the functional analysis of the mutated AR offers a possible treatment modality. METHODS: Specific binding of dihydrotestosterone in the patient's genital skin fibroblasts, thermostability, and 5 alpha-reductase activity were evaluated. Furthermore, an AR gene mutation was detected by direct sequencing. The ability of the mutant receptor to activate androgen-responsive elements in the DNA was determined by recreating an AR expression vector and cotransfection experiments. RESULTS: The newborn patient with partial androgen insensitivity showed a qualitative and quantitative binding defect. A point mutation in the ligand binding domain was identified as the underlying cause. Transactivation assays demonstrated that increasing androgen concentration can restore the function of the mutated receptor completely. Therefore, the patient received androgen stimulation which resulted in good growth of his external genitalia and underwent surgical correction in the male direction. CONCLUSIONS: Diagnosis and therapy in affected patients will be improved identifying the molecular mechanisms that cause the various forms of sex ambiguity. Exact characterization of AR activation and function may offer a possible treatment modality in patients with the androgen insensitivity syndrome. Our results led to a surgical correction of our newborn patient in the male direction.

3-Oxo-5-alpha-Steroid 4-Dehydrogenase↗

PubMed1995

[A retroperitoneal hydatid cyst--a rare manifestation of Echinococcus granulosus].

A rare case of a retroperitoneal cyst of Echinococcus granulosus in a male adult is presented. Due to its extension and infiltration of important anatomical structures the hydatid cyst could not be completely removed by operation. Therefore the patient was treated with albendazole for 10 months after surgery. The efficiency of this combined therapy was documented by CT-scan, specific blood tests and histopathological findings.

Albendazole↗

PubMed1994

Leukocyte/endothelial interactions and blood-brain barrier permeability in rats during cerebral superfusion with LTB4.

The experimental study analyses the vasomotor response (change of diameter of pial arterioles and venules), and blood-brain barrier function of the pia-arachnoidea at the rat brain surface before, during and after cerebral superfusion with 1.5 or 15.0 nM LTB4 in mock CSF. Leukocyte dynamics were studied by assessment of their centerline velocity, of rolling along ("roller") and attachment to ("sticker") the venular wall of white blood cells intravitally stained by Rhodamin 6G. Superfusion of the brain with LTB4 at both dose levels led to dilation of arterioles to 130% (p < 0.001), while of venules to 117% (p < 0.001) of control. The centerline velocity of leukocytes increased from 0.7 to 0.9 mm/s, however, only after superfusion with LTB4 at the high dose level. LTB4 induced a dose-dependent rolling (p < 0.01) and sticking of leukocytes (p < 0.001). Yet, a delay of about 60 min between cerebral administration of LTB4 and the maximal response of leukocyte rolling and sticking was observed. Whereas the blood-brain barrier was not opened by cerebral superfusion with 1.5 or 15.0 nM LTB4, for i.v. Na(+)-fluorescein, barrier leakage was promptly induced by 30.0 nM. The present findings demonstrate that cerebral administration of LTB4 by superfusion of the exposed brain surface is eliciting a pronounced vasomotor response, whereas the induction of leukocyte/endothelial interactions is less impressive.

Animals↗

PubMed1990

Effect of stimulation of leukocyte chemotaxis by fMLP on white blood cell behaviour in the microcirculation of rat brain.

The role of white blood cells in acute cerebral disorders such as ischemia or stroke is still unclear. Therefore, in the present study we investigated the effects of the leukotaxin n-formyl-methionyl-leucyl-phenylalanine (fMLP) on white blood cell endothelial-cell interactions in the rat brain surface microcirculation. An improved closed cranial window technique was applied. Superfusion of fMLP in rising concentrations (10(-8) - 10(-5) M) was seen to induce rolling and adherence of leukocytes to teh endothelium of small venules. Rolling was more effectively stimulated than firm attachment. fMLP-induced vasodilation was more pronounced in arterioles than in venules. In this study it has been shown that the hydrophilic fMLP is effectively stimulating neutrophil chemotaxis across the blood-brain barrier. Further, the closed cranial window preparation is useful to analyze quantitatively properties of activated leukocytes, which may be pertinent in injury to the blood-brain barrier and induction of microcirculatory disturbances.

Animals↗

PubMedDate not supplied

Adjuvant interferon alpha therapy in renal cell carcinoma (RCC): prognostic value of DNA cytophotometry.

BACKGROUND: Adjuvant immunotherapy with interferon alpha in non-metastatic RCC is still controversial. It was the aim of the present study to investigate whether tumor ploidy can help to isolate a group of patients profitting from this treatment. MATERIALS AND METHODS: Survival data of 119 patients undergoing tumor nephrectomy because of a non-metastatic RCC were analyzed retrospectively. Ploidy was measured in every tumor by means of DNA-cytophotometry. 24 patients received an adjuvant therapy with interferon alpha for one year. Statistical evaluation was performed by the Kaplan-Meier-Method with the logrank-test. RESULTS: Ploidy could be measured in all tumors. 56 (47%) tumors showed a diploid, 63 (53%) an aneuploid DNA-distribution. Ploidy was seen to be a good prognostic factor in RCC with significantly better survival in patients with diploid than those with aneuploid tumors. The adjuvant interferon therapy provided a marginal however not significant better survival in diploid tumors. Patients with aneuploid RCC had no benefit from this treatment. CONCLUSIONS: The data show that an interferon treatment in non-metastatic RCC might improve survival in patients with the prognostic better diploid tumors. However further investigations are necessary to give a general recommendation for this therapy in this group of patients. Additional molecular tumor factors like S-phase analysis and others might also improve patient selection.

Aneuploidy↗

PubMedDate not supplied

Adjuvant immunotherapy in renal cell carcinoma--comparison of interferon alpha treatment with an untreated control.

BACKGROUND: Adjuvant immunotherapy of RCC with interferon alpha is still controversial. It was the aim of this study to investigate, whether a selected group of patients with a non-metastatic RCC can profit from this therapy. MATERIALS AND METHODS: Survival data of 125 patients with a non-metastatic RCC, who underwent a tumor-nephrectomy were analyzed retrospectively, 33 of these patients received an adjuvant immunotherapy with interferon alpha for 1 year. All tumors were classified by the TNM-system. Statistical evaluation was performed by the Kaplan-Meier-Method and the logrank-test. RESULTS: Tumor stage was seen to be an important prognostic factor in RCC with a significantly better outcome in pT2- as compared to pT3-tumors. Tumor grading was without any prognostic relevance. Adjuvant interferon alpha therapy had no effect on overall survival. After separation of the patients into pT2- and pT3/4-tumors again interferon alpha showed no significant benefit for one of the 2 groups. CONCLUSIONS: The adjuvant therapy with interferon alpha shows no significant benefit in the treatment of non-metastatic RCC. Tumor stage is no suitable factor to select a group of patients, who might profit from an interferon alpha therapy. Further studies are necessary to isolate better selection factors.

Carcinoma, Renal Cell↗