Xenofon Giannakopoulos

Penetration of Antimicrobial Agents into the Prostate

In the present review article, the penetration of antimicrobial agents into prostatic fluid and tissue was examined. Three major factors determining the diffusion and concentration of antimicrobial agents in prostatic fluid and tissue are the lipid solubility, dissociation constant (pKa) and protein binding. The normal pH of human prostatic fluid is 6.5–6.7, and it increases in chronic prostatitis, ranging from 7.0 to 8.3. A greater concentration of antimicrobial agents in the prostatic fluid occurs in the presence of a pH gradient across the membrane separating plasma from prostatic fluid. Of the available antimicrobial agents, β-lactam drugs have a low pKa and poor lipid solubility, and thus penetrate poorly into prostatic fluid, expect for some cephalosporins, which achieve greater than or equal to the inhibitory concentration. Good to excellent penetration into prostatic fluid and tissue has been demonstrated with many antimicrobial agents, including tobramycin, netilmicin, tetracyclines, macrolides, quinolones, sulfonamides and nitrofurantoin.

MRI in the Histologic Characterization of Testicular Neoplasms

OBJECTIVE The purpose of our study was to investigate the potential role of MRI in the preoperative characterization of the histologic type of testicular tumors and, more specifically, to differentiate seminomatous from nonseminomatous testicular neoplasms. MATERIALS AND METHODS Twenty-one patients with histologically proven germ cell testicular tumors underwent MRI of the scrotum on a 1.5-T unit. T2- and T1-weighted sequences before and after i.v. administration of gadolinium chelate were performed. MRI studies were retrospectively reviewed by two radiologists and findings were correlated with the histopathologic diagnosis. An attempt was made to differentiate seminomatous from nonseminomatous testicular tumors on the basis of signal intensity and homogeneity of the lesions, presence of fibrovascular septa, tumor encapsulation, and patterns of contrast enhancement. Interobserver agreement was assessed using weighted kappa statistics. RESULTS MRI findings correctly characterized 19 (91%) of 21 testicular neoplasms (nine seminomatous and 10 nonseminomatous testicular tumors), with excellent interobserver agreement. The presence of an intratesticular lesion of predominantly low signal intensity on T2-weighted images, with septa enhancing more than tumor tissue after contrast material administration, was more suggestive for the diagnosis of a seminoma. Tumors that were markedly heterogeneous both on unenhanced and contrast-enhanced images were indicative of a nonseminomatous neoplasm. CONCLUSION Our study shows that MRI provides a credible preoperative differentiation of seminomatous from nonseminomatous testicular tumors, with excellent interobserver agreement.

Orbital Metastasis from Prostatic Carcinoma

A rare case of orbital metastasis from carcinoma of the prostate in a 76-year-old man who presented with pain in his left eye, mild proptosis and reduced visual acuity is reported. Cranial CT scanning demonstrated large bone metastases in the left orbit. The patient underwent orbital evisceration. The histopathological studies that were based on the morphological and immunohistochemical findings confirmed the histological diagnosis of orbital metastasis arising from prostatic carcinoma with neuroendocrine features.

Inhibition of benzo(a)pyrene-induced carcinogenesis by vitamin C alone and by vitamin C/vitamin E and selenium/glutathione

The reduction on peroxidation caused by benzopyrenes by some naturally occurring antineoplastic agents was studied in this experimental work. Inhibition/reduction of experimental carcinogenesis induced by benzo(a)pyrene by vitamin C alone and by vitamin C/vitamin E and selenium/glutathione was attempted in 224 female Wistar rats divided in four groups. Injected with 10.08 mL benzo(a)pyrene, the animals were treated with some naturally occurring substances like vitamin C alone and a combination of anticarcinogens. By calculating the carcinogenic potency of benzo(a)pyrene and the anticarcinogenic potency of substances used as well as histological examination of developed tumors and survival time of treated animals, it was found that vitamin C exerts a significant anticarcinogenic effect of 8.3 units and that the combination of the two anticarcinogens used produced a significant prolongation of the animals survival time with anticarcinogenic potency of 22.1 and 22.2 units, respectively. This is considered a potent anticarcinogenic effect. The question of an additional supportive administration of such agents complementary to the conventional cancer chemotherapy in humans is raised. Of course, further studies are needed.

Giant simple renal cyst complicated with hypertension.

Solitary renal cysts are a common and usually asymptomatic occurrence in older patients. They may be associated with hypertension or abdominal disturbances, as they can be responsible for compression of surrounding tissues and distortion of renal vessels. This report presents an interesting case of a hypertensive patient with a solitary renal cyst of a marked size. Owing to the high risk of performing a surgical procedure in such a patient, a distinct therapeutic solution was opted for. Successful management of this case was achieved by a combination of percutaneous fluid aspiration and injection of alcohol and Vibramycin inside the cystic cavity. Percutaneous fluid evacuation combined with the administration of a sclerosing agent is suggested as a safe and effective alternative for cyst decompression and blood pressure normalisation.

An Update on Sexual Transmission of Zika Virus

Zika virus (ZIKV) is a single-stranded RNA virus belonging to the arthropod-borne flaviviruses (arboviruses) which are mainly transmitted by blood-sucking mosquitoes of the genus Aedes. ZIKV infection has been known to be rather asymptomatic or presented as febrile self-limited disease; however, during the last decade the manifestation of ZIKV infection has been associated with a variety of neuroimmunological disorders including Guillain–Barré syndrome, microcephaly and other central nervous system abnormalities. More recently, there is accumulating evidence about sexual transmission of ZIKV, a trait that has never been observed in any other mosquito-borne flavivirus before. This article reviews the latest information regarding the latter and emerging role of ZIKV, focusing on the consequences of ZIKV infection on the male reproductive system and the epidemiology of human-to-human sexual transmission.