Drug-resistance mutations in antiretroviral-naïve patients with established HIV-1 infection in Mexico.

OBJECTIVES: To describe the prevalence of baseline drug-resistance mutations, resistance to antiretroviral drugs, and the subsequent virological response to therapy in treatment-naïve patients from Mexico with established HIV-1 infection. METHODS: Resistance testing was performed on plasma samples from antiretroviral-naïve patients. Data on mutations associated with antiretroviral drug resistance were obtained using Stanford software (http://hivdb.stanford.edu). RESULTS: Ninety-six treatment-naïve individuals were enrolled in the study during 2002-2003. Of these, 83 patients (86%) had at least one resistance mutation and 15 (16%) had drug resistance. At baseline, the mean plasma viral load was 299 834 HIV-1 RNA copies/mL, and at follow-up it was 37 620 copies/mL (P<0.0001). Primary mutations in the reverse transcriptase region were observed in 15% of patients. For nucleoside inhibitors, mutations T215Y/C and F77L (3%) and D67N/S, T69N and M184V (2%), were detected. For nonnucleoside inhibitors, mutations K103N/R (6%), Y181C (3%) and G190A (2%) were detected. Overall, 6% of patients showed resistance to delavirdine and nevirapine, 4% to efavirenz, and 2% to lamivudine and nelfinavir. Twelve patients showed no response to treatment and three of these patients had antiretroviral drug resistance. CONCLUSIONS: The prevalence of baseline drug-resistance mutations found in this study was similar to that found in previous reports for newly HIV-infected individuals, although access to and management of antiretrovirals in Mexico are different.

[Metachronous contralateral Leydig cell tumor of the testis: conservative treatment]. / Tumor testicular de células de Leydig contralateral metacrónico: tratamiento conservador.

Leydig cell tumors are the primary nongerm cell tumors of the testis, comprising approximately 1 to 3% of all testicular neoplasms. These tumors are bilateral in 5 to 10% of cases. Hypoechoic testicular nodule associated to a child virilising syndrome or adult gynecomastia with negative testis tumor markers (AFP, B-HCG) show a high index suspicion for this entity. We report a case of metachronous contralateral Leydig cell tumor in a 32 years old man with a 9 year interval between presentations, in which we performed local excision of the lesion. Diagnostic an therapeutic aspects are reviewed in literature. Since preoperative diagnosis of Leydig cell tumors in difficult and clinical course unpredictible, radical orchiectomy has been the standard treatment. Emphasis is made on conservative management opportunity in patients with only one testis, small tumors (less than 2.5 cm) with biopsies from tumor bed negative and wishes to remain fertile and/or refuses androgen supplementation. Follow-up is mandatory by performing scrotal ultrasounds. CT scan, Chest X-Ray, tumor markers and hormone determinations (testosterone, estradiol, progesterone, LH and FSH).

[Large renal leiomyoma]. / Leiomioma renal voluminoso.

Renal leiomyomas are uncommon between renal tumors, and they have a benign mesenchymatous origin. Because of their low incidence, unspecific symptomatology an not well-defined iconographic semiology, they often raise problems with differential diagnosis from kidney masses, although they are often big size lessions. We report a patients with incidentally diagnosis of big solid left renal mass, who underwent radical nephrectomy resulting kidney pelvis leiomyoma. Diagnostic, histological and therapeutic aspects are briefly review in literature. Emphasis is made on the relevance of a high index suspicion considering big solid asymptomatic renal masses in middle-age women. Specially in renal tumors with well-defined limits and abscence of locoregional and systemic dissemination. We emphasized usefulness of Magnetic Angioresonance, immunohystochemical test and conservative surgery opportunity in small renal leiomyomas preoperatively confirmed.

[Synchronous association of Bellini collecting ducts and pyelic transitional cell carcinoma]. / Asociación sincrónica de carcinoma de los conductos colectores de Bellini y carcinoma transicional pielico.

Bellini's collecting ducts carcinoma represent a subgroup within renal carcinoma with an incidence of 0.4 to 2% of all renal tumours. The collecting ducts share their embryological origin in Wölf's duct with the calices, renal pelvis and ureter. This common embryological origin could justify the association of carcinoma originated in the collecting ducts with transitional urothelial carcinoma. This paper contributes two patients with Bellini's collecting ducts carcinoma associated to "in situ" carcinoma and transitional papillar carcinoma in the adjacent renal pelvis respectively. The authors review the diagnostic, pathoanatomical and therapeutical aspects found in the literature. A high index of suspicion is required to diagnose a case of Bellini's carcinoma in the face of predominantly central-medullar renal solid lesions, with infiltrating growth that causes morphological changes in the excretory system without deforming the external renal outline. The authors highlight the value of immunohistochemical studies to reach a diagnosis, considering the natural history and the sombre prognosis of this uncommon renal neoplasia.

Meningoencefalitis por Listeria monocytogenes (Informe de cinco casos). / Meningoencephalitis by Listeria monocytogenes (Report of 5 cases)

Se presentam cinco casos de meningoencefalitis por Listeria monocytogenes. Se senalan las caracteristicas clinicas epidemiologicas, serologicas y bacteriologicas del microrganismo asi como su escasa frecuencia en nuestro medio, y las dificultades en su diagnostico tanto desde el punto de vista clinico, como de laboratorio. Se hace una revision de la literatura mundial y nacional sobre el tema

[Hepatic abscess caused by Salmonella]. / Absceso hepático por Salmonella.

In Mexico liver abscesses are frequent and most of them are produced by amibas. Sometimes the ethiology is caused by bacterias and its ethiological diagnosis is difficult therefore the specifics treatment takes longer and this may increase mortality. In this issue, the clinical laboratory scand caracteristics are presented on six patients having liver abscess caused by Salmonella as well as its evolution and reaction to treatment.