Induced luteolysis in the primate: rapid loss of luteinizing hormone receptors

The molecular mechanisms involved in luteolysis are still unclear in the primate. This study aimed to investigate the effect of induced luteolysis on the ovarian luteinizing hormone (LH) receptor and the steroidogenic enzyme, 3beta-hydroxysteroid dehydrogenase (3beta-HSD) in the marmoset monkey. Luteolysis was induced in the mid-luteal phase either directly by systemic prostaglandin F2alpha (PGF2alpha), or indirectly by LH withdrawal using systemic gonadotrophin releasing hormone antagonist (GnRHant) treatment. The LH receptor was studied by isotopic mRNA in-situ hybridization and in-situ ligand binding and 3beta-HSD expression was studied using isotopic mRNA in-situ hybridization and immunohistochemistry. Induced luteolysis was associated with a reduction in the expression of LH receptor (P < 0.0001) and 3beta-HSD mRNA, closely followed by a reduction in the LH receptor (P < 0.05) and 3beta-HSD protein concentrations within 24 h. There were no differences in the findings whether luteolysis was induced with PGF2alpha or GnRHant. This study shows that disparate mechanisms to induce luteolysis in the primate result in an identical rapid loss of the LH receptor and 3beta-HSD. In conclusion, induced luteolysis leads to rapid loss of the steroidogenic pathway in luteal cells.      

Semen parameters and testicular pathology in men with testicular cancer and contralateral carcinoma in situ or bilateral testicular malignancies

We evaluated 14 patients with bilateral testicular tumour, one-sided tumour and contralateral carcinoma in situ (CIS) of the testis or testis tumour in single testis with respect to their fertility. We analysed semen parameters, serum hormones [follicle-stimulating hormone (FSH), luteinizing hormone (LH) and testosterone], testicular sonography, testicular volumes and testicular histology prior to further anti-cancer treatment. Ten out of 14 patients showed normal or reduced sperm concentrations, while 4/14 patients were azoospermic. Serum FSH levels showed a significant negative correlation with sperm concentrations in patients with testicular malignancies (r = -0.64, P = 0.025). Testicular volumes revealed a significant positive correlation with semen parameters in patients with testes that were affected by CIS (r = 0.733, P = 0.038). We conclude that even bilateral testicular cancer and/or CIS do not preclude fertility and, therefore, patients should be offered andrological investigation and therapy, including possibly surveillance strategy or the chance for cryopreservation of the semen prior to further treatment in order to preserve their chances for paternity.      

Hyperexcitability and reduced low threshold potassium currents in auditory neurons of mice lacking the channel subunit Kv1.1

A low voltage-activated potassium current, I _KL, is found in auditory neuron types that have low excitability and precisely preserve the temporal pattern of activity present in their presynaptic inputs. The gene Kcna1 codes for Kv1.1 potassium channel subunits, which combine in expression systems to produce channel tetramers with properties similar to those of I _KL, including sensitivity to dendrotoxin (DTX). Kv1.1 is strongly expressed in neurons with I _KL, including auditory neurons of the medial nucleus of the trapezoid body (MNTB). We therefore decided to investigate how the absence of Kv1.1 affected channel properties and function in MNTB neurons from mice lacking Kcna1 . We used the whole cell version of the patch clamp technique to record from MNTB neurons in brainstem slices from Kcna1 -null (−/−) mice and their wild-type (+/+) and heterozygous (+/−) littermates. There was an I _KL in voltage-clamped −/− MNTB neurons, but it was about half the amplitude of the I _KL in +/+ neurons, with otherwise similar properties. Consistent with this, −/− MNTB neurons were more excitable than their +/+ counterparts; they fired more than twice as many action potentials (APs) during current steps, and the threshold current amplitude required to generate an AP was roughly halved. +/− MNTB neurons had excitability and I _KL amplitudes identical to the +/+ neurons. The I _KL remaining in −/− neurons was blocked by DTX, suggesting the underlying channels contained subunits Kv1.2 and/or Kv1.6 (also DTX-sensitive). DTX increased excitability further in the already hyperexcitable −/− MNTB neurons, suggesting that −/− I _KL limited excitability despite its reduced amplitude in the absence of Kv1.1 subunits.     

Myositis associated with a newly described microsporidian, Trachipleistophora hominis, in a patient with AIDS.

Microsporidia are zoonotic protozoa which were rare human pathogens prior to 1985, when Enterocytozoon bieneusi was described in human immunodeficiency virus-infected patients with chronic diarrhea. Another species, Encephalitozoon (Septata) intestinalis, is associated with diarrhea and chronic sinusitis, and approximately 25 cases have been reported in the literature. However, other microsporidial infections in human immunodeficiency virus-infected patients remain extremely rare. We report the first case of a Pleistophora sp.-like microsporidian infection presenting as a progressive severe myosotis associated with fever and weight loss. The organism was demonstrated by light microscopy and electron microscopy in corneal scrapings, skeletal muscle, and nasal discharge. Electron microscopy showed an electron-dense surface coat with "sunflare"-like projections surrounding all stages of development of meronts (two to four nuclei, dividing by binary fission), sporonts, and sporoblasts. Division of sporonts, in which sporonts separate from the thick outer coat, creating a sporophorous vesicle, is by binary fission, differentiating this organism from Pleistophora sp. The spore measures 4.0 by 2.5 microns and has a rugose exospore. A new genus and species, Trachipleistophora hominis, has been established for this parasite. The patient was treated with albendazole, sulfadiazine, and pyrimethamine, and the clinical symptoms resolved.