Intraocular CNTF reduces vision in normal rats in a dose-dependent manner

PURPOSE: CNTF is a neuroprotective agent for retinal degenerations that can cause reduced electroretinogram (ERG) amplitudes. The goal of the present study was to determine the effects of intraocular delivery of CNTF on normal rat visual function. METHODS: Full-field scotopic and photopic ERG amplitudes and spatial frequency thresholds of the optokinetic response (OKR) of adult Long-Evans rats were measured before and after intravitreous injection of CNTF or subretinal delivery of adenoassociated virus-vectored CNTF (AAV-CNTF) into one eye. Visual acuity was also measured by using the Visual Water Task in AAV-CNTF-injected animals. Multiunit luminance thresholds were recorded in the superior colliculus after CNTF injection, and the eyes were examined histologically. RESULTS: In eyes injected with a high dose of CNTF, ERG amplitudes and OKR thresholds measured through CNTF-injected eyes were decreased by 45% to 70% within 6 days after injection. ERG amplitudes had begun to recover by 21 days, whereas OKR thresholds only began to recover after 56 days. Neither OKR thresholds nor ERG amplitudes fully recovered until 90 to 100 days. When measured in the superior colliculus at 2 weeks after CNTF injection, luminance thresholds were elevated by 0.35 log units. In AAV-CNTF-injected eyes, OKR thresholds, and visual acuity were reduced by approximately 50% for at least 6 months, and scotopic and photopic ERG b-waves were reduced by 30% to 50%. Photoreceptor loss occurred in the injected regions in some of the eyes. By contrast, comparison of dose-response analysis with a dose-response study of light damage strongly suggests that therapeutic doses of CNTF exist that do not suppress ERG responses. CONCLUSIONS: Intraocular delivery of CNTF, which preserves photoreceptors in animal models of retinal degeneration, impairs visual function in normal rats at very high doses, but not at lower doses that still provide protection from constant light damage.     

CD4+ CD8+ (thymocyte-like) T lymphocytes present in blood and skin from patients with atopic dermatitis suggest immune dysregulation

BACKGROUND: Atopic dermatitis (AD) is a chronic inflammatory skin disease expressed early in life. Disease development is primarily determined by as yet unknown genetic factors, leading to the accumulation of activated T lymphocytes in the skin. OBJECTIVES: To investigate the nature of these T cells. METHODS: T-cell lines could be established from AD skin biopsies, but not from normal skin or AD peripheral blood, when placed in RPMI 1640 medium with 10% human AB serum, antibiotics, and the T-lymphocyte growth factors interleukins 2 and 4. The cell lines were subjected to phenotypic analysis using a fluorescence-activated cell sorter and compared with lymphocytes from AD and normal control peripheral blood. RESULTS: T-cell lines from 22 of 24 consecutive skin biopsies taken from 24 adult patients with AD were established. All cells were T lymphocytes expressing several activation markers. A significant proportion of the lymphocytes had stable expression of a CD4+ CD8+ phenotype (26% +/- 6%; mean +/- SEM). Such double-positive T lymphocytes are normally only seen in the thymus and not in the peripheral immune system. CD4+ CD8+ cells in peripheral blood of the patients (12.5% +/- 3.3%) were also detected. CONCLUSIONS: We suggest that a basic pathophysiological change in AD may be a faulty maturation of the T-lymphocyte system, leading to skin inflammation with CD4+ CD8+ T lymphocytes resembling immature T cells. This is likely to lead to skewing of many immune reactions in the patients.     

Cancer cell expression of urokinase-type plasminogen activator receptor mRNA in squamous cell carcinomas of the skin

In this study we have used in situ hybridization with radiolabeled antisense RNA probes to examine the expression of mRNA for urokinase-type plasminogen activator and its receptor in histologic samples of squamous cell (n = 7) and basal cell (n = 7) carcinomas of the skin. Messenger RNA for both urokinase-type plasminogen activator and its receptor were expressed in all of the squamous cell carcinomas, but could not be detected in the basal cell carcinomas. In all of the seven squamous cell carcinomas a signal for urokinase-type plasminogen activator receptor mRNA was detected focally in well-differentiated cancer cells surrounding keratinized pearls, and in four specimens urokinase-type plasminogen activator receptor mRNA was in addition expressed by cancer cells at the edge of invasively growing strands of tumor. Urokinase-type plasminogen activator mRNA expression was found in virtually all the cancer cells of the squamous cell carcinomas, and importantly we found, by hybridizations for urokinase-type plasminogen activator and its receptor mRNA on adjacent sections of squamous cell carcinomas, that it was exactly the invading cancer cells that simultaneously expressed both these components required for plasmin-mediated proteolysis at the cell surface. We have previously shown that both urokinase-type plasminogen activator and its receptor mRNA are expressed by the leading-edge keratinocytes in regenerating epidermis during mouse skin wound healing, and that wound healing is impaired in mice made deficient in plasminogen by targeted gene disruption. We propose that there are similarities between the mechanisms of generation and regulation of extracellular proteolysis during skin re-epithelialization and squamous cell carcinoma invasion. The ability of the squamous carcinoma cells to mimic the "invasive" phenotype of re-epithelializing keratinocytes may be one of the factors that make squamous cell carcinomas more aggressive tumors than basal cell carcinomas.     

Left ventricular remodeling after infarction: sequential MR imaging with oral nicorandil therapy in rat model

PURPOSE: To use magnetic resonance (MR) imaging in quantification of the short- and long-term effects of therapy with orally administered nicorandil on left ventricular (LV) geometry and function independent of infarction size. MATERIALS AND METHODS: Forty-six rats were subjected to reperfused infarction and randomly divided into two groups. Group 1 rats (n = 21) were treated with nicorandil (3 mg/kg/day in drinking water) for 4 days before infarction and 8 weeks after infarction (hereafter, the nicorandil group). Group 2 rats (n = 25) received tap water for the same period and served as the control group. Mesoporphyrin- (as a necrosis-specific agent) enhanced MR imaging was used to define necrotic myocardium on day 2 after infarction in all 46 animals. Contrast material-enhanced MR images showed large but identical infarction size in 11 control and 11 nicorandil rats. Only these 22 rats underwent repeat MR imaging at 8 weeks after infarction. The following variables were measured: LV volumes, ejection fraction, mass, wall thickness, and infarction size. Student t test and analysis of variance for repeated measurements were used for statistical analysis. RESULTS: The size of the necrotic region on mesoporphyrin-enhanced MR images was 39% +/- 3 of the size of the left ventricle in the control group and 41% +/- 2 in the nicorandil group (difference not significant, unpaired Student t test). Pretreatment with nicorandil for 6 days before imaging did not reduce LV dilation or improve function compared with those in control animals with identical infarction size. Eight weeks after infarction, control animals showed deterioration in LV function, wall thinning, and gradient in regional dysfunction (analysis of variance test). Nicorandil produced significant salutary effects on LV ejection fraction (37% +/- 3 in the nicorandil group vs 24% +/- 3 in the control group), end-diastolic volume (0.53 mL +/- 0.03 vs 0.65 mL +/- 0.04), end-systolic volume (0.36 mL +/- 0.03 vs 0.49 mL +/- 0.05), LV wall thickening in remote noninfarcted myocardium (28% +/- 2 vs 19% +/- 1), and a rim of infarction (16% +/- 2 vs 8% +/- 1) (P <.05 for all parameters). The increase in LV mass was reduced in the nicorandil group (0.73 g +/- 0.03) compared with that in the control group (0.89 g +/- 0.04) (P <.05). CONCLUSION: In animals studied longitudinally, MR imaging demonstrated the deleterious changes in LV geometry and function in the period after infarction and the salutary effects of medical therapy.     

The SF-36 health status questionnaire in assessing patients with epistaxis secondary to hereditary hemorrhagic telangiectasia

BACKGROUND: This study assesses the ability of the short form 36 (SF-36), a validated health status survey, to measure the health of patients with epistaxis due to hereditary hemorrhagic telangiectasia (HHT). METHODS: Thirty-eight patients completed the SF-36 and symptom-specific questionnaires. They were asked to rate their epistaxis as severe, moderate, or mild. The SF-36 data are compared with a reference population and analyzed with respect to the subgroups. RESULTS: The scores for each dimension of health were significantly reduced (p < 0.05) when compared with the reference population for all dimensions except pain. When compared with the patients' ratings of severity, a significant correlation was detected in five dimensions (p < 0.05). CONCLUSION: The SF-36 reflects the reduced health status of patients with epistaxis due to HHT. Changes in the SF-36 score could be used as an outcome measure in assessing efficacy of treatment of this condition.     

Urokinase- and tissue-type plasminogen activators in keratinocytes during wound reepithelialization in vivo

Urokinase- and tissue-type plasminogen activators (u-PA and t-PA) were identified immunohistochemically during reepithelialization of mouse and human skin wounds, by means of polyclonal and monoclonal antibodies. In incised mouse skin wounds u-PA immunoreactivity was found in keratinocytes at the edge of the wound after 12 h, and at days 2 to 10 after wounding it was found in virtually all keratinocytes of the epithelial outgrowth that gradually covered the wound. At day 14, the epidermis appeared normal and no u-PA immunoreactivity was detected. t-PA immunoreactivity was found from day 5 to day 10 in some keratinocytes located superficially in the epidermal outgrowths near the edge of the mouse wounds. In 3- and 5-day old human skin wounds, u-PA immunoreactivity was found in keratinocytes in the epithelial outgrowths, whereas no t-PA immunoreactivity was detected. No u-PA and no t-PA immunoreactivity was found in normal mouse and human epidermis. The specificity of the staining was supported by a variety of controls, including absorption of the polyclonal antibodies with highly purified u-PA and t-PA preparations and zymographic analysis of extracts of wound tissue. The function of the plasminogen activators during reepithelialization is discussed and it is suggested that the keratinocytes use plasmin activated by u-PA for dissecting their way through the provisional matrix in the upper part of the granulation tissue.     

Acute gastric mucosal lesions, haemodynamic and microcirculatory changes in the thermally injured rat

Early postburn changes in central haemodynamics, organ blood flow distribution and morphology of the gastric mucosa were studied using a standarized thermal skin injury model. Organ blood flow and cardiac output were determined using radioactive microspheres. In the control animals no marked changes in cardiac output or organ blood flow were observed, and the gastric mucosa remained essentially undamaged. After burn injury and no fluid resuscitation, cardiac output decreased by 78 per cent, and blood flow to the stomach, pancreas, spleen, muscle, skin and kidneys also decreased markedly and to about the same degree as the cardiac output, however the adrenal flow remained roughly unchanged at the baseline level. Gross and microscopic lesions developed in the stomach, especially in the corpus. In animals given fluid resuscitation after burn injury cardiac output decreased by 38 per cent during the experiment, but blood flow in the stomach, brain, kidneys and spleen remained fairly constant, while pancreatic and muscle blood flow decreased and adrenal blood flow increased markedly. The gastric mucosa showed only minor microscopic, but no macroscopic lesions at the end of the experiment.

The results indicate that acute thermal skin injury induces profound changes in central haemodynamics and organ blood flow which can, however, largely be overcome by adequate fluid resuscitation. The data also suggest that, as in other examples of 'stress ulceration', impaired mucosal blood flow may underlie the stress ulceration which complicates severe burns.