Photoreceptor death, trophic factor expression, retinal oxygen status, and photoreceptor function in the P23H rat

PURPOSE: To relate the oxygen environment of the retina to photoreceptor stability, protection, and function in the P23H rat. METHODS: Heterozygote P23H-3 (Line 3) rats were studied. Photoreceptor death rates were assessed with the TUNEL technique for detection of fragmenting DNA, in a developmental series from postnatal day (P)16 to P105 (adult). In adult retinas, trophic factor status was assessed with immunohistochemistry, intraretinal oxygen environment with O(2)-sensing electrodes, and photoreceptor function by the flash-evoked, dark-adapted electroretinogram (ERG), recorded in anesthetized animals. RESULTS: Photoreceptor death begins by P16; peaks at P25, when the frequency of TUNEL(+) profiles exceeds 70/mm of retina; and then declines to low (<5/mm) adult rates. Compared with that in nondegenerative Sprague-Dawley (SD) rats, the rate of photoreceptor death is abnormally high from P16 and remains several-fold higher than normal into young adulthood. In addition, the outer nuclear layer is reduced to approximately half of control thickness, and the levels of ciliary neurotrophic factor (CNTF), glial fibrillary acidic protein (GFAP), fibroblast growth factor (FGF)-2, and FGF-2/FGFR1 colocalization are markedly upregulated. O(2) tension and uptake are relatively normal in the inner retina, but uptake is considerably reduced, and O(2) tension is significantly raised in the outer retina. Surviving photoreceptors generate an a-wave with normal peak latency but sharply reduced amplitude. CONCLUSIONS: Excess photoreceptor degeneration in the P23H-3 retina begins just after eye opening, peaks in early postnatal life, and then slows, but persists into adulthood. In the adult retina, surviving photoreceptors operate in an environment that is chronically hyperoxic (and therefore toxic) and in which protective factors (CNTF, FGF-2) are chronically upregulated. The net result, slow degeneration and degraded function in an environment that is both toxic and protective, may be representative of adult photoreceptor status in a number of human retinal degenerations. Hyperoxia-induced photoreceptor death may be a self-reinforcing factor that increases oxidative stress in surviving photoreceptors.     

Selective sensory denervation by capsaicin aggravates adriamycin-induced cardiomyopathy in rats

Capsaicin-sensitive sensory nerves that contain calcitonin gene-related peptide (CGRP) contribute significantly to cardioprotective mechanisms. In this study, the possible role of capsaicin-sensitive afferent nerves in the development of congestive heart failure was examined in an established model of adriamycin-induced experimental cardiomyopathy in rats. Systemic treatment with capsaicin was utilized to deplete sensory neuropeptides from cardiac afferent nerves. Echocardiography was applied to assess the cardiac function in adriamycin-treated rats pretreated with capsaicin or its vehicle. In control rats, adriamycin treatment produced a reduction in the fractional shortening of the left ventricle and an increase in the ratio of the left atrial diameter and the aortic diameter, indicative of a decreased myocardial contractility and heart failure only at 3–4 weeks post-treatment. In contrast, in capsaicin-pretreated rats, a deterioration of the cardiac function was already evident 1 week after the cessation of adriamycin administration, while the clinical signs associated with cardiomyopathy were more severe and displayed a significantly more rapid progression. Immunohistochemistry revealed a complete depletion of calcitonin gene-related peptide from cardiac sensory nerves after systemic capsaicin treatment. This study has demonstrated that elimination of capsaicin-sensitive afferent nerves promotes the development and progression of adriamycin-induced myocardial dysfunction. The results suggest that interfering with capsaicin/vanilloid receptor function and/or perturbation of the myocardial CGRP metabolism may open up new perspectives concerning prevention and/or alleviation of the pathological changes that follow adriamycin treatment.     

Perinatal and intrafamily transmission of hepatitis B virus in three generations of a low-prevalence population

Family members of 47 hepatitis B virus (HBV)-carrier pregnant women were tested for the presence of hepatitis B surface antigen (HBsAg), other markers of HBV infection, and hepatitis A virus (HAV) antibodies. Eleven members of six families were found to be HBV DNA positive. Five of the anti-HBe-positive persons were found to be HBV DNA carriers, too. The mean age of the HBV DNA carriers was found to be lower than that of Hbe carriers; therefore, it is suggested that seroconversion to HBe occurs before the resolution of HBV DNA carrier state. Superinfection with hepatitis A virus was not found to influence the elimination of HBV-carrier state, as there was no correlation found between the hepatitis A exposure and the hepatitis B virus markers in the families. The low HBV prevalence in the population (0.3%) was in contrast to the high prevalence of the families of the HBV-carrier mothers (27.1%) and family members with HBV markers (50.4%). Significant positive correlation was found in the proportion of HBV-positive children, and the HBV history of their parents. When fathers were shown to be seronegative, the probability of HBV transmission was reduced by a factor of 6 (12.5% instead of 75%) probably due to reduced viral load and possibly by other factors. Several results indicate, that the noncytocidal hepatitis B virus clearing mechanism suggested by Guidotti et al. [1996, 1999] was effective also in the HBV-carrier human population.     

Luminol-dependent chemiluminescence is related to the extracellularly released reactive oxygen intermediates in the case of rat neutrophils activated by formyl-methionyl-leucyl-phenylalanine

Luminol is a non-radical-specific amplifying molecule which produces light upon interaction with various reactive oxygen intermediates (ROIs). ROI production of rat peritoneal polymorphonuclear leukocytes (PMNLs) elicited by 2.3 microM formyl-methionyl-leucyl-phenylalanine (fMLP) results in a biphasic luminol-dependent chemiluminescence (LDCL) signal. Whereas ROIs are also produced intracellularly, as judged by flow cytometry, addition of non-membrane-permeable catalase reduces the first and second phases of the LDCL signal to around 3% and less than 3%, respectively. This suggests that in the case of fMLP-stimulated rat PMNLs, the LDCL signal is related to the ROIs in the extracellular medium and hydrogen peroxide has a key role in the formation of the LDCL signal. In the presence of the non-specific myeloperoxidase inhibitor Na-azide, the first phase of the LDCL signal decreases slightly (87+/-8%), while the second phase almost disappears (< 3%), indicating the myeloperoxidase dependence of the second phase. The hydroxyl radical scavenger histidine results in an 84+/-4% and a 71+/-4% decrease in the intensity of the first and second phases, respectively. Based on these data, it is concluded that hydrogen peroxide might be the source of hydroxyl radicals directly oxidizing luminol in the first phase of the LDCL signal, while in the second phase it serves as a substrate of myeloperoxidase in the peroxidation reaction of the luminol.     

Successful idebenone therapy of hypertrophic cardiomyopathy in Friedreich ataxia

Severe hypertrophic cardiomyopathy in a 15 years old child with Friedreich ataxia was treated with idebenone on the basis of a preliminary study reported in the literature. After 3 months of treatment the muscle thickness and mass and idices of diastolic function on echocardiogram and ischaemic signs on ECG changed significantly. IN CONCLUSION: Our data proves the preliminary results, so idebenobe treatment is very effective in the disease, where a deficiency of frataxin is involved in the regulation of mitochondral iron content which is responsible for myocardial injury. We suggest the widespread use of idebenone to treat patients with Friedreich ataxia and hypertrophic cardiomyopathy to improve the fatal prognosis of this type of cardiomyopathy.     

Transfusion problems in surgery and anesthesiology. The causes, consequences, prevention and treatment of perioperative anemia

INTRODUCTION: The classical indication for blood transfusion is the correction of oxygen delivery failure, and the elimination of tissue ischaemia. Such indications in the surgical and anesthesiological practice are the acute haemorrhagic states (trauma, acute gastrointestinal bleeding, intraoperative hemorrhage), as well as diseases associated with chronic blood loss (occult bleeding caused by malignancies, and ulcerating processes etc.). The traditional surgical and anesthesiological viewpoint has adopted a remarkably liberal approach to the indication of blood transfusion, and a whole range of its subtle, medium-long term adverse effects has been taken into account only recently. The purpose of this review was to analyze the causes and pathophysiological consequences of perioperative anemia and blood loss, as well as to reconsider the proper indications of blood transfusion in the view of immunological sequela. The most recent data on the transfusion related immuno-depression and immunomodulation are summarized. The authors wish to provide clues for the definition of "transfusion trigger", in addition, methods available for the clinical practice to reduce blood demand and to restore oxygen transport capacity during surgical and anesthesiological interventions are revisited. Based on the review of the literature and the personal experience of the authors the practical recommendations concerning the administration of blood and blood products should be summarized as follows: 1. Blood transfusion is rarely indicated if the hemoglobin level is above 10 g/dl, and in fact always necessary if it is less than 6 g/dl, especially, if the anemia developed acutely. 2. The "transfusion trigger" is subject to continued debate, and whether a particular patient with intermediary (6-10 g/dl) Hb levels should be transfused or not must be assessed in the perspective of the potential complications initiated by the inadequate oxygenation. 3. If major co-morbidity (e.g. emphysema, ischaemic heart disease) is present, 10 g/dl Hb, in case of respirator dependency 12 g/dl Hb levels justify the administration of transfusion. If feasible, the beneficial effects of allogenous blood sparing methodologies should be utilized. CONCLUSIONS: Although the National Blood Supply Service is excellently organized in Hungary, the current clinical practice is not satisfactory. The use of up-to-date methods at the average surgical departments is suboptimal, and due to the lack of knowledge concerning the recent advances in immunology the clinicians are far too liberal in the indication of blood transfusion. The objective is to establish a modern surgical and anesthesiological transfusion practice based on the solid understanding of immunological facts, and to modernize the continued education, as well as to improve the financing of costly blood saving methodologies.     

Microbiological and serological diagnostic methods to detect intrauterine and perinatal infections

Due to the revolutional development in sampling devices, transport media, automated equipments, microvolume probes and molecular microbiological techniques in the last decade new possibilities have become available for diagnosing microbiologically congenital infections in both the mother and the foetus and the newborn. This minireview gives an insight into the diagnostic tuls of clinical microbiology and infection serology by showing laboratory diagnostic processes of most frequent protozoal, viral and bacterial infections step-by-step. It exhibit an almost complete list of transplacental, intrauterinal and connatal infections. Attention is also focused to the complexity of the interrelationship between the clinical microbiology and infection serology data concerning the infections of the mother and her offspring.     

Biological activity of persimmon (Diospyros kaki) peel extracts

Fractionated extracts of persimmon (Diospyros kaki) peels were studied for cytotoxic activity, multidrug resistance (MDR) reversal activity, anti-human immunodeficiency virus (HIV) activity and anti-Helicobacter pylori (H. pylori) activity. The potent cytotoxic activity against human oral squamous cell carcinoma cells (HSC-2) and human submandibular gland tumor (HSG) cells was found in the acetone fractions (A4 and A5) with IC(50) ranging from 21 to 59 micro g/mL. However, the cytotoxic activity was not correlated with the radical intensity of the fractions. Three 70% MeOH extract fractions (70M2-4) produced radical and efficiently scavenged the O(2)(-) produced by hypoxanthine and xanthine oxidase reaction. All of the fractions tested were not effective for anti-H. pylori and anti-HIV. Fractions H3 and H4 of hexane extract, and M2 and M3 of MeOH extract showed a remarkable MDR reversal activity comparable with that of (+/-)-verapamil (a positive control). These results indicate the therapeutic value of persimmon peel extracts as potential antitumor and MDR-reversing agents.     

A novel telomerase template antagonist (GRN163) as a potential anticancer agent

Telomerase, the enzyme responsible for proliferative immortality, is expressed in essentially all cancer cells, but not in most normal human cells. Thus, specific telomerase inhibition is potentially a universal anticancer therapy with few side effects. We designed N3'-->P5' thio-phosphoramidate (NPS) oligonucleotides as telomerase template antagonists and found that their ability to form stable duplexes with the telomerase RNA subunit was the key factor for antitelomerase activity. In biochemical assays 11-13-mer NPS oligonucleotides demonstrated sequence- and dose-dependent inhibition of telomerase with IC(50) values <1 nM. Optimization of the sequence, length, and bioavailability resulted in the selection of a 13-mer NPS oligonucleotide, GRN163, as a drug development candidate. GRN163 inhibited telomerase in a cell-free assay at 45 +/- 7 pM, and in various tumor cell lines at approximately 1 nM and approximately 0.3-1.0 micro M in the presence and absence of carriers, respectively. GRN163 was competitive with telomeric primer binding, primarily because of hybridization to human telomerase RNA (hTR) component. Tumor cells treated with GRN163 in culture underwent telomere shortening, followed by cellular senescence or apoptosis after a period of time that generally correlated with initial telomere length. In a flank DU145 (prostate cancer) xenograft model, parenterally administered GRN163 caused suppression of tumor growth in the absence of gross toxicity. These data demonstrate that GRN163 has significant potential for additional development as an anticancer agent.