Network


Latest external collaboration on country level. Dive into details by clicking on the dots.

Hotspot


Dive into the research topics where Walter Jose Koff is active.

Publication


Featured researches published by Walter Jose Koff.


The Journal of Urology | 1990

Malformations of the Epididymis in Undescended Testis

Walter Jose Koff; Renato Scaletscky

Epididymal abnormalities in undescended testes are probably more common than suggested in the literature but only sporadic reports are found on this subject. For many years discussions have centered around the ideal age to operate on patients with undescended testes and consequently increase chances for future fertility. We analyzed 66 patients (82 testes) treated for undescended testis in our department, with special distinction between ectopia and cryptorchidism. Abnormalities ranged from simple epididymal elongation to more complex forms, such as complete disruption between the testis and epididymis. Among 49 ectopic testes the epididymides of 19 (38.8%) displayed more severe abnormalities in addition to elongation, while 16 (32.6%) showed only an elongated epididymis and 14 (28.6%) were normal. Among the 33 cryptorchid testes 29 (87.9%) showed the more complex anomalies and elongation, 3 (9.1%) were normal and only 1 (3%) was elongated. Our results demonstrate a much higher incidence of complex epididymal abnormalities in cryptorchidism (p less than 0.001). Elongated epididymis may present problems for sperm maturation and transportation, although with no other associated abnormality most can be regarded as patent. In our theory cases of elongation plus other major abnormalities probably are associated with severe impairment in sperm maturation and hindered transportation, with the future intrascrotal or extrascrotal position of the testis or early surgical repair being of little importance in terms of fertility.


Cancer Investigation | 2008

Polymorphic CAG and GGC Repeat Lengths in the Androgen Receptor Gene and Prostate Cancer Risk : Analysis of a Brazilian Population

Brasil Silva Neto; Walter Jose Koff; Vanderlei Biolchi; Cleber Brenner; Karlo D. Biolo; Poli Mara Spritzer; Ilma Simoni Brum

Variations in transcriptional activity of the androgen receptor (AR) are related to polymorphic CAG and GGC repeats in exon 1 of the AR gene. We investigated the association between CAG and GGC repeat length and the risk of prostate cancer in a case-control study from a Brazilian population. We evaluated 49 patients and 51 healthy controls. DNA was extracted from peripheral leukocytes and the AR gene was analyzed by fragment analysis (GeneMapper software, Applied Biosystems, Foster City, California, USA). CAG and GGC mean lengths were not different between cases and controls. The risk for prostate cancer was higher for CAG repeats ≤ 21 (OR = 2.44 [95% CI 1.03–5.81]) as well as for total repeat lengths (CAG + GGC) ≤37 (OR = 2.46 [95% CI 0.98–6.18]). GGC repeats (≤17 and > 17) were not associated with risk for prostate cancer (OR = 1.13 [95% CI 0.47–2.75]). In conclusion, fewer number of CAG repeats and total repeats (CAG + GGC) in the AR gene may be associated with increased risk for prostate cancer.


Radiology | 2011

Prostate cancer: prediction of biochemical failure after external-beam radiation therapy--Kattan nomogram and endorectal MR imaging estimation of tumor volume.

Antonio C. Westphalen; Walter Jose Koff; Fergus V. Coakley; Valdair Francisco Muglia; John Neuhaus; Ralph T. Marcus; John Kurhanewicz; Rebecca Smith-Bindman

PURPOSE To determine whether magnetic resonance (MR) imaging and MR spectroscopic imaging findings can improve predictions made with the Kattan nomogram for radiation therapy. MATERIALS AND METHODS The institutional review board approved this retrospective HIPAA-compliant study. Ninety-nine men who underwent endorectal MR and MR spectroscopy before external-beam radiation therapy for prostate cancer (January 1998 to June 2007) were included. Linear predictors were calculated with input variables from the study sample and the Kattan original coefficients. The linear predictor is a single weighted value that combines information of all predictor variables in a model, where the weight of each value is its association with the outcome. Two radiologists independently reviewed all MR images to determine extent of disease; a third independent reader resolved discrepancies. Biochemical failure was defined as a serum prostate-specific antigen level of 2 ng/mL (2 μg/L) or more above nadir. Cox proportional hazard models were used to determine the probabilities of treatment failure (biochemical failure) in 5 years. One model included only the Kattan nomogram data; the other also incorporated imaging findings. The discrimination performance of all models was determined with receiver operating characteristics (ROC) curve analyses. These analyses were followed by an assessment of net risk reclassification. RESULTS The areas under the ROC curve for the Kattan nomogram and the model incorporating MR imaging findings were 61.1% (95% confidence interval: 58.1%, 64.0%) and 78.0% (95% confidence interval: 75.7%, 80.4%), respectively. Comparison of performance showed that the model with imaging findings performed significantly better than did the model with clinical variables alone (P < .001). Overall, the addition of imaging findings led to an improvement in risk classification of about 28%, ranging from approximately a minimum of 16% to a maximum of 39%, depending on the risk change considered important. CONCLUSION MR imaging data improve the prediction of biochemical failure with the Kattan nomogram after external-beam radiation therapy for prostate cancer. The number needed to image to improve the prediction of biochemical failure in one patient ranged from three to six.


International Journal of Transgenderism | 2007

Clinical Characteristics, Psychiatric Comorbidities and Sociodemographic Profile of Transsexual Patients from an Outpatient Clinic in Brazil

Maria Inês Rodrigues Lobato; Walter Jose Koff; Sidnei Schestatsky; Camila Chaves; Analídia Rodolpho Petry; Tiago Crestana; Juliana Trindade Amaral; Fernanda de Quadros Onófrio; Jaqueline Salvador; Esalba Silveira; Alexandre Annes Henriques

ABSTRACT Objective: To provide a description of our transsexual population. Method: This descriptive observational study included 138 patients with a diagnosis of Trans-sexualism in Brazil, between March 1998 and September 2005. Demographic, clinical and psychiatry data were collected. Results: Age ranged from 16 to 54 years; 88.4% were male. The prevalence of sexually transmitted diseases was 19.5%, and 17.6% were HIV-positive. Hormone therapy was reported by 91.2%, and 47.4% referred drug and alcohol use; 14.2%, attempted suicide; and 12.5%, history of sexual abuse. Self-mutilation was reported by 5.2%s. Fifty-nine patients (42.7%) had at least one currently psychiatric comorbidity (axis I or II). Conclusions: Mental health professionals have a central role in coordinating the multidisciplinary care of transsexuals.


Journal of Psychiatric Research | 2013

Serum concentrations of brain-derived neurotrophic factor in patients with gender identity disorder

Anna-Martha V. Fontanari; Tahiana Andreazza; Ângelo Brandelli Costa; Jaqueline Salvador; Walter Jose Koff; Bianca Wollenhaupt de Aguiar; Pamela Ferrari; Raffael Massuda; Mariana Pedrini; Esalba Silveira; Paulo Silva Belmonte-de-Abreu; Clarissa Severino Gama; Márcia Kauer-Sant'Anna; Flávio Kapczinski; Maria Inês Rodrigues Lobato

Gender Identity Disorder (GID) is characterized by a strong and persistent cross-gender identification that affects different aspects of behavior. Brain-derived neurotrophic factor (BDNF) plays a critical role in neurodevelopment and neuroplasticity. Altered BDNF-signaling is thought to contribute to the pathogenesis of psychiatric disordersand is related to traumatic life events. To examine serum BDNF levels, we compared one group of DSM-IV GID patients (n = 45) and one healthy control group (n = 66). Serum BDNF levels were significantly decreased in GID patients (p = 0.013). This data support the hypothesis that the reduction found in serum BDNF levels in GID patients may be related to the psychological abuse that transsexuals are exposed during their life.


Acta Cirurgica Brasileira | 2013

Oxidative stress evaluation of ischemia and reperfusion in kidneys under various degrees of hypothermia in rats

Emanuel Burck dos Santos; Walter Jose Koff; Tomáz de Jesus Maria Grezzana Filho; Samanta Daiana de Rossi; Lisiane Treis; Silvia Bona; Karla Lais Pêgas; Betina Stifelman Katz; Fabiola Schons Meyer; Norma Anair Possa Marroni; Carlos Otavio Corso

PURPOSE To design an animal model of ischemia-reperfusion (I/R) in kidneys and evaluate the role that predetermined ranges of local hypothermia plays on markers of stress-oxydative as well as on histologic sections. METHODS Twenty eight male rats Wistar, under general anesthesia, undergone right nephrectomy (G0, control group) followed by left kidney ischemia during 40 min. Four temperatures groups were designed, with seven animals randomized for each group: normothermic (G1, ±37ºC), mild hypothermia (G2, 26ºC), moderate hypothermia (G3, 15ºC) and deep hypothermia (G4, 4ºC). Left kidney temperature was assessed with an intraparenchymal probe. Left nephrectomy was performed after 240 min of reperfusion. After I/R a blood sample was obtained for f2-IP. Half of each kidney was sent to pathological evaluation and half to analyze CAT, SOD, TBARS, NO3, NO2. RESULTS Histopathology showed that all kidneys under I/R were significantly more injured than the G0 (p<0.001). TBARS had increased levels in all I/R groups compared with the G0 (p<0.001). CAT had a significant difference (p<0.03) between G1 and G4. Finally, no difference was found on SOD, NO3, NO2 nor on f2-IP. CONCLUSION This model of I/R was efficient to produce oxidative-stress in the kidney, showing that 4ºC offered significant decrease in free radicals production, although tissue protection was not observed.


Psychiatry and Clinical Neurosciences | 2012

Minimum 2-year follow up of sex reassignment surgery in Brazilian male-to-female transsexuals.

Jaqueline Salvador; Raffael Massuda; Tahiana Andreazza; Walter Jose Koff; Esalba Silveira; Fernanda Kreische; Lívia de Souza; Maria Helena de Oliveira; Tiago Elias Rosito; Brisa Simoes Fernandes; Maria Inês Rodrigues Lobato

general fatigue were resolved after a switch to blonanserin. Hypoglycemia was not detected on Day 167 following a 75-g OGTT. Her auditory hallucinations and persecutory delusions were improved (BPRS score: 21), therefore she was discharged on Day 180. Because complaints of hypoglycemia are similar to the sedative effect of SGA, clinicians may overlook hypoglycemia in patients with schizophrenia. We previously reported another case of hypoglycemia induced by quetiapine. In that case, replacement of quetiapine with perospirone improved the symptoms of hypoglycemia but asymptomatic hypoglycemia was still present upon repeat OGTT. In the current case, a switch to blonanserin improved not only the symptoms of hypoglycemia but also hypoglycemia itself upon repeat OGTT. Because blonanserin is a new antipsychotic, its effect on glucose metabolism has not been established. However, this report suggests that a switch to blonanserin may be useful when hypoglycemia induced by SGA occurs.


The Aging Male | 2014

Performance of Massachusetts Male Aging Study (MMAS) and androgen deficiency in the aging male (ADAM) questionnaires in the prediction of free testosterone in patients aged 40 years or older treated in outpatient regimen

Renan Desimon Cabral; Luciane Busin; Tiago Elias Rosito; Walter Jose Koff

Abstract Objective: At present, calculated free testosterone assessment is considered as the gold standard in diagnosing male hypogonadism. However, this assessment is not available for all the individuals diagnosed with decreased testicular function. The investigators of this study were, thus, prompted to evaluate whether the androgen deficiency in the aging male (ADAM) and the Massachusetts Male Ageing Study (MMAS) questionnaires could be used to replace biochemical parameters in the diagnosis for hypogonadism in men aged 40 years and above. Methods: We evaluated 460 men, aged 40 years and above, all volunteers of a screening program for prostate cancer based at the Hospital de Clínicas of Porto Alegre. In this study, we assessed the efficiency of the ADAM and MMAS questionnaires in diagnosing Brazilian men with low levels of total, calculated free and bioavailable testosterone. Results: The sensitivity of the ADAM questionnaire in diagnosing the calculated free testosterone was 73.6%, whereas specificity was 31.9%. ADAM could be used to properly classify our cohort into normal or hypogonadal individuals in 52.75% of the cases. The sensitivity of the MMAS questionnaire was 59.9%, whereas the specificity was 42.9%, resulting in a successful classification of 51.4% of the patients. Conclusion: The ADAM and MMAS questionnaires showed adequate sensitivity in diagnosing male patients with low levels of free testosterone. However, because of the lack of specificity, these tools cannot replace calculated free testosterone assessments in men aged 40 years and above.


International Braz J Urol | 2004

Adenomatoid tumor of supra-renal gland

Nancy Tamara Denicol; Fabrício Rodrigues Lemos; Walter Jose Koff

Adenomatoid tumors of adrenal gland are rare, asymptomatic neoplasias, with benign behavior, and usually are diagnosed incidentally. We report a case of a voluminous adenomatoid tumor of left adrenal gland in a 42-year old man who sought evaluation because of renal colic due to left nephrolithiasis. During the investigation, a tumor localized in left adrenal gland was identified by ultrasonography (14.3 x 10.5 x 19.0). The patient underwent adrenalectomy and pyelolithotomy with histopathological and immunohistochemical diagnosis of adenomatoid tumor of adrenal gland, being the largest one described in the literature to the moment. The patient does not present any signs of recurring lesion after a 3-year follow-up.


International Journal of Clinical Practice | 2006

A randomised, double‐blind study comparing the efficacy and tolerability of controlled‐release doxazosin and tamsulosin in the treatment of benign prostatic hyperplasia in Brazil

Antonio Carlos Lima Pompeo; Charles Rosenblatt; Eduardo B. Bertero; C. T. Da Ros; Carlos Eurico Dornelles Cairoli; R. Damião; Eric Roger Wroclawski; Walter Jose Koff; F. Mesquita; G. E. Pinheiro

Brazilian patients with benign prostatic hyperplasia were randomised in a 12‐week, double‐blind, double‐dummy study to receive doxazosin gastrointestinal therapeutic system (GITS) 4 mg q.i.d. (n = 82) or tamsulosin 0.4 q.i.d. (n = 83). Primary endpoints were the absolute and percentage change from baseline in symptoms measured by International Prostate Symptom Score (IPSS). Secondary endpoints included IPSS, quality‐of‐life (QOL) question from the IPSS, and questions 6 and 7 of the Sexual Function Abbreviated Questionnaire (SFAQ) at weeks 4 and 12. Doxazosin GITS and tamsulosin improved IPSS with no significant differences between groups at week 12. During weeks 4–8, tamsulosin‐treated patients demonstrated a slower improvement (p < 0.001) in IPSS than doxazosin GITS‐treated patients. The proportion of satisfied patients was observed earlier with doxazosin GITS (p = 0.006) vs. tamsulosin. At week 12, the proportion of patients with little or no difficulty at ejaculation (Q6 of SFAQ) was higher in the doxazosin GITS group (p = 0.019). Both treatments were well tolerated.

Collaboration


Dive into the Walter Jose Koff's collaboration.

Top Co-Authors

Avatar

Milton Berger

Universidade Federal do Rio Grande do Sul

View shared research outputs
Top Co-Authors

Avatar

Brasil Silva Neto

Universidade Federal do Rio Grande do Sul

View shared research outputs
Top Co-Authors

Avatar

Jaqueline Salvador

Universidade Federal do Rio Grande do Sul

View shared research outputs
Top Co-Authors

Avatar

Esalba Silveira

Universidade Federal do Rio Grande do Sul

View shared research outputs
Top Co-Authors

Avatar

Ilma Simoni Brum

Universidade Federal do Rio Grande do Sul

View shared research outputs
Top Co-Authors

Avatar

Maria Inês Rodrigues Lobato

Universidade Federal do Rio Grande do Sul

View shared research outputs
Top Co-Authors

Avatar

Tiago Elias Rosito

Universidade Federal do Rio Grande do Sul

View shared research outputs
Top Co-Authors

Avatar

Vanderlei Biolchi

Universidade Federal do Rio Grande do Sul

View shared research outputs
Top Co-Authors

Avatar

Eduardo Terra Lucas

Universidade Federal do Rio Grande do Sul

View shared research outputs
Top Co-Authors

Avatar

Raffael Massuda

Universidade Federal do Rio Grande do Sul

View shared research outputs
Researchain Logo
Decentralizing Knowledge