Archive of Medical Research

Functional involvement of Annexin-2 in cAMP induced AQP2 trafficking.

Annexin-2 is required for the apical transport in epithelial cells. In this study, we investigated the involvement of annexin-2 in cAMP-induced aquaporin-2 (AQP2) translocation to the apical membrane in renal cells. We found that the cAMP-elevating agent forskolin increased annexin-2 abundance in the plasma membrane enriched fraction with a parallel decrease in the soluble fraction. Interestingly, forskolin stimulation resulted in annexin-2 enrichment in lipid rafts, suggesting that hormonal stimulation might be responsible for a new configuration of membrane interacting proteins involved in the fusion of AQP2 vesicles to the apical plasma membrane. To investigate the functional involvement of annexin-2 in AQP2 exocytosis, the fusion process between purified AQP2 membrane vesicles and plasma membranes was reconstructed in vitro and monitored by a fluorescence assay. An N-terminal peptide that comprises 14 residues of annexin-2 and that includes the binding site for the calcium binding protein p11 strongly inhibited the fusion process. Preincubation of cells with this annexin-2 peptide also failed to increase the osmotic water permeability in the presence of forskolin in intact cells. Altogether, these data demonstrate that annexin-2 is required for cAMP-induced AQP2 exocytosis in renal cells.

Tamma G, Procino G, Mola MG, Svelto M, Valenti G.

Department of General and Environmental Physiology, University of Bari, Via Amendola 165/A, 70126, Bari, Italy.

Quadriceps muscle function characteristics in severely obese and nonobese adolescents.

The purpose of this cross-sectional study was to compare quadriceps muscle strength and fatigue between severely obese (body mass index 34 kg/m(2)) and nonobese adolescents. Maximal isokinetic torque and angle of peak torque as well as isometric torque at short (40 degrees of knee flexion) and long (80 degrees of knee flexion) muscle length were measured using an isokinetic dynamometer. Muscle fatigue was quantified as the percent torque loss during an isokinetic voluntary protocol and an electrical stimulation isometric protocol. Obese adolescents produced greater absolute isokinetic (+16%; P < 0.05) and isometric torque at short (+25%; P < 0.01) but not at long muscle length (P > 0.05) compared to their lean counterparts. The angle of peak torque was significantly lower in obese than in nonobese subjects (-11%; P < 0.05), i.e., obese produced their maximal strength at shorter muscle length. Isokinetic and isometric torque normalized to the fat-free mass were not significantly different between the two groups. No significant difference in voluntary and stimulated torque loss was observed between groups. Muscle strength per unit of fat-free mass and muscle fatigue were similar in the obese and nonobese adolescents tested in this study, therefore suggesting that obesity has little or no effect on quadriceps muscle function characteristics. On the other hand, it remains to be confirmed whether the observed quadriceps muscle length specificity contributes to the reduced functional capacity of obese adolescents during complex motor tasks involving deep knee flexion (squatting, kneeling).

Maffiuletti NA, Jubeau M, Agosti F, De Col A, Sartorio A.

Neuromuscular Research Laboratory, Schulthess Klinik, Lengghalde 2, 8008, Zurich, Switzerland, Nicola.Maffiuletti@kws.ch.

Flap suture - a simple technique for the revision of hypotony maculopathy following trabeculectomy with mitomycin C.

BACKGROUND: A serious complication following trabeculectomy with mitomycin C (MMC) is intraocular hypotony with hypotony maculopathy, papilledema, flattening of the anterior chamber, corneal decompensation and a decrease in visual acuity. We describe a new simple surgical technique for the treatment of hypotony maculopathy following trabeculectomy with MMC. METHODS: In a prospective consecutive case study, 16 patients with hypotony maculopathy following trabeculectomy with MMC were included. Through the intact conjunctiva, additional 10.0 nylon sutures were placed through the scleral flaps into the adjacent sclera. Assessment of visual acuity, intraocular pressure (IOP) measurement and fundoscopy were performed on the 1st and 7th day postoperatively and 1, 3 and 6 months postoperatively. Photography of the bleb and the posterior pole and optical coherence tomography imaging of the posterior pole were performed. RESULTS: Before surgery (flap suture), the mean IOP was 2.8 mmHg (+/-1.1; range from 1 to 4 mmHg). It was 24.9 +/- 11.7 mmHg (range; 9-48 mmHg) on the 1st postoperative day, 15.7 +/-8.1 mmHg (range; 5-35 mmHg) on day 7, 11.1 +/-4.1 mmHg (range; 5-20 mmHg) 1 month after surgery, 9.3 +/-3.9 mmHg (range; 2-20 mmHg) after 3 months, and 9.6 +/-4.2 mmHg (range; 2-20 mmHg) after 6 months. The best corrected mean visual acuity was 20/50 before trabeculectomy and 20/160 before flap suture. It improved to 20/63 at 6 months postoperatively. Clinical signs of hypotony maculopathy disappeared in all patients. No bleb leakage was observed in any patient during follow-up. CONCLUSION: Resuturing the scleral flap through the intact conjunctiva is an effective and minimally invasive method to treat hypotony maculopathy following trabeculectomy with MMC. Thus, opening the conjunctiva can be avoided.

Eha J, Hoffmann EM, Wahl J, Pfeiffer N.

Department of Ophthalmology, Johannes Gutenberg-University, Langenbeckstr. 1, 55101, Mainz, Germany, Eha@augen.klinik.uni-mainz.de.

Prevalence of crowded optic discs in adult Chinese. The Beijing Eye Study.

BACKGROUND: To determine the prevalence of crowded optic discs and their associations with ocular and general parameters. METHODS: The Beijing Eye Study included 4,439 subjects out of 5,324 subjects invited to participate (response rate 83.4%) with an age of 40+ years. The present investigation consisted of 8,594 eyes (96.8%) of 4,324 subjects (97.4%) for whom readable fundus photographs of at least one eye were available. The main outcome parameter was the presence of crowded optic discs, defined as small discs with an unsharp and slightly prominent disc border without signs of pathology. RESULTS: Crowded optic discs were detected in 265 (3.1 +/- 0.2%) eyes of 168 subjects (84 women). The prevalence rate was 3.8% +/- 0.3% (95% confidence interval: 3.2%, 4.4%) per subject. Crowded optic discs were significantly associated with age (P < 0.05%) and disc size (P < 0.001). They were statistically not associated with gender (P = 0.08), intraocular pressure (P = 0.06), refractive error (P = 0.17), visual field defects (P = 0.53), and best corrected visual acuity (P = 0.57). CONCLUSIONS: Crowded optic discs are present in about 38 out of 1000 adult Chinese in Northern China, with small optic discs as the main associated factor. These data may be helpful for the assessment of a risk for nonarteritic anterior ischemic optic neuropathy.

You QS, Xu L, Jonas JB.

Beijing Institute of Ophthalmology, Beijing Tongren Hospital, Capital University of Medical Sciences, Beijing, China.

Refractive properties of the healthy human eye during acute hyperglycemia.

PURPOSE: To measure the refractive properties of the healthy human eye during acute hyperglycemia by means of Scheimpflug imaging and Hartmann-Shack aberrometry. METHODS: Acute hyperglycemia was induced in five healthy subjects (two males, three females, mean age +/-SD 24.8 years +/- 4.6) by means of an oral glucose tolerance test (OGTT) after subcutaneous somatostatin injection. Before and every 30 minutes after the OGTT, measurements with Scheimpflug imaging and Hartmann-Shack aberrometry were performed. The main outcome measures were the thickness and shape of the lens, and the ocular refractive error and higher order aberrations. The equivalent refractive index of the lens was calculated from these parameters. Measurements at baseline and during hyperglycemia were analyzed by means of Wilcoxon signed rank sum tests. RESULTS: During hyperglycemia (mean blood glucose level at baseline: 4.0 mmol/l; mean maximal blood glucose level: 18.4 mmol/l) no changes could be found in the refractive properties within the group. In one subject, a hyperopic shift (0.4 D) was observed, together with a more convex shape of the anterior lens surface and a decrease in the equivalent refractive index of the lens. CONCLUSIONS: This study shows that hyperglycemia generally does not cause changes in the refractive properties of the healthy eye. Nevertheless, in one subject a hyperopic shift accompanied by a change in shape and refractive index of the lens was measured. This finding could provide an explanation for the mechanism underlying the refractive changes that are often observed during hyperglycemia.

Wiemer NG, Eekhoff EM, Simsek S, Heine RJ, Ringens PJ, Polak BC, Dubbelman M.

Department of Ophthalmology, VU University Medical Center, P.O. Box 7057, 1007 MB, Amsterdam, The Netherlands, ngm.wiemer@vumc.nl.

An X-STR meiosis study in Kurds and Germans: allele frequencies and mutation rates.

X-linked short tandem repeats (X-STRs) play an important supplementary role in the field of forensic genetics, especially in deficiency cases. This paper presents population genetic data for the microsatellite markers DXS8378, DXS6800, DXS101, HPRTB, and DXS8377 in a German and a Kurdish population sample. Buccal swabs were obtained from 217 unrelated healthy German individuals (107 women and 110 men) from the area of Münster and 208 unrelated Kurdish individuals (103 women and 105 men), immigrants mainly from Northern Iraq. Additionally, more than 1,200 meiotic transfers (419 paternal and 819 maternal meioses) were investigated in the systems DXS6800, DXS101, and DXS8377. Five mutations were found in the system DXS8377. With the power of discrimination in females [PD(F)] ranging from 0.81 (DXS8378 in Kurds) to 0.99 (DXS8377 in Germans), the investigated X-STRs systems turned out to be highly informative in the two populations.

Fracasso T, Schürenkamp M, Brinkmann B, Hohoff C.

Institute of Legal Medicine, Münster University, Röntgenstr. 23, 48149, Münster, Germany, tony.fracasso@ukmuenster.de.

Intercomparison study on (152)Eu gamma ray and (36)Cl AMS measurements for development of the new Hiroshima-Nagasaki Atomic Bomb Dosimetry System 2002 (DS02).

In the process of developing a new dosimetry system for atomic bomb survivors in Hiroshima and Nagasaki (DS02), an intercomparison study between (152)Eu and (36)Cl measurements was proposed, to reconcile the discrepancy previously observed in the Hiroshima data between measurements and calculations of thermal neutron activation products. Nine granite samples, exposed to the atomic-bomb radiation in Hiroshima within 1,200 m of the hypocenter, as well as mixed standard solutions containing known amounts of europium and chlorine that were neutron-activated by a (252)Cf source, were used for the intercomparison. Gamma-ray spectrometry for (152)Eu was carried out with ultra low-background Ge detectors at the Ogoya Underground Laboratory, Kanazawa University, while three laboratories participated in the (36)Cl measurement using accelerator mass spectrometry (AMS): The Technical University of Munich, Germany, the Lawrence Livermore National Laboratory, USA and the University of Tsukuba, Japan. Measured values for the mixed standard solutions showed good agreement among the participant laboratories. They also agreed well with activation calculations, using the neutron fluences monitored during the (252)Cf irradiation, and the corresponding activation cross-sections taken from the JENDL-3.3 library. The measured-to-calculated ratios obtained were 1.02 for (152)Eu and 0.91-1.02 for (36)Cl, respectively. Similarly, the results of the granite intercomparison indicated good agreement with the DS02 calculation for these samples. An average measured-to-calculated ratio of 0.98 was obtained for all granite intercomparison measurements. The so-called neutron discrepancy that was previously observed and that which included increasing measured-to-calculated ratios for thermal neutron activation products for increasing distances beyond 1,000 m from the hypocenter was not seen in the results of the intercomparison study. The previously claimed discrepancy could be explained by insufficient understanding of the measured data.

Hoshi M, Endo S, Tanaka K, Ishikawa M, Straume T, Komura K, Rühm W, Nolte E, Huber T, Nagashima Y, Seki R, Sasa K, Sueki K, Fukushima H, Egbert SD, Imanaka T.

Research Institute for Radiation Biology and Medicine, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima, 734-8553, Japan, mhoshi@hiroshima-u.ac.jp.

Microvascular decompression of cochleovestibular nerve.

The role of microvascular decompression (MVD) in the management of trigeminal neuralgia, hemifacial spasms and glossopharyngeal neuralgia is well-established. However, controversy persisted as to the use of MVD in cochleovestibular neurovascular compression syndrome. This report provides a review of all the published studies on MVD of the eighth (8th) nerve in alleviating cochleovestibular symptoms and presents three additional patients who underwent MVD of the eighth nerve for tinnitus or vertigo. Nineteen studies were identified. Five were case reports. The remaining have sample sizes ranging from 4 to 207 patients. Quantitative and qualitative reviews of all studies were performed, focusing on the selection criteria for surgery, efficacy and safety of the procedure. Selection criteria for surgery were variable. No standardised outcome measures were used and all studies rely on patient subjective assessment of surgical outcome. Nonetheless, the results suggest that MVD of the eighth nerve produces good outcome with low morbidity in selected cases.

Yap L, Pothula VB, Lesser T.

The Walton Centre for Neurology and Neurosurgery, Liverpool, UK, leesien@tiscali.co.uk.

Secretion of mouse growth hormone by transduced primary human keratinocytes: prospects for an animal model of cutaneous gene therapy

BACKGROUND: Keratinocytes are a very attractive vehicle for ex vivo gene transfer and systemic delivery because proteins secreted by these cells may reach the circulation via a mechanism that mimics the natural process. METHODS: An efficient retroviral vector (LXSN) encoding the mouse growth hormone gene (mGH) was used to transduce primary human keratinocytes. Organotypic raft cultures were prepared with these genetically modified keratinocytes and were grafted onto immunodeficient dwarf mice (lit/scid). RESULTS: Transduced keratinocytes presented a high and stable in vitro secretion level of up to 11 microg mGH/10(6)cells/day. Conventional epidermal sheets made with these genetically modified keratinocytes, however, showed a drop in secretion rates of > 80% due to detachment of the epithelium from its substratum. Substitution of conventional grafting methodologies with organotypic raft cultures completely overcame this problem. The stable long-term grafting of such cultures onto lit/scid mice could be followed for more than 4 months, and a significant weight increase over the control group was observed in the first 40 days. Circulating mGH levels revealed a peak of 21 ng/ml just 1 h after grafting but, unfortunately, these levels rapidly fell to baseline values. CONCLUSIONS: mGH-secreting primary human keratinocytes presented the highest in vitro expression and peak circulatory levels reported to date for a form of GH with this type of cells. Together with previous data showing that excised implants can recover a remarkable fraction of their original in vitro mGH secretion efficiency in culture, the factors that might still hamper the success of this promising model of cutaneous gene therapy are discussed. Copyright (c) 2008 John Wiley & Sons, Ltd.

J Gene Med. 2008 Apr 3

.Peroni CN, Cecchi CR, Rosauro CW, Nonogaki S, Boccardo E, Bartolini P.
Biotechnology Department, National Nuclear Energy Commission (IPEN?CNEN), Cidade Universitária, São Paulo, Brazil.

Cytotoxic-Antineoplastic Derivatives of Prenyl-1,2-naphthohydroquinone.

Several new prenyl-1,2-naphthohydroquinone derivatives have been prepared by chemical modifications of Diels-Alder products which were obtained from cycloaddition of alpha-myrcene to 1,2-benzoquinone and then evaluated in vitro for their cytotoxic activity against A-549 lung carcinoma, HT-29 colon carcinoma, and MB-231 breast adeno-carcinoma culture cells. Most of them exhibited GI(50) values in the muM-concentration level.

Molinari A, Oliva A, Ojeda C, Del Corral JM, Castro MA, Cuevas C, San Feliciano A.

Instituto de Química, Pontificia Universidad Católica de Valparaíso, Valparaíso, Chile. Fax: +56 32 2273-422.