Biomedical subjects

N Yoshimura

Publications and source records attributed to N Yoshimura.

At least 145 records · Page 8Linked to original sources

PubMed1999

Role of nitric oxide during the initial phase of reperfusion after retinal ischemia in the rat.

The onset of reperfusion and the recovery of the ERG b-wave following retinal ischemia was examined among three groups of rats: group 1 (n = 12) and group 2 (n = 6) received pretreatment with NG-nitro-L-arginine (20 mg/kg, i.p., 2 h before ischemia) followed by intravenous injection of saline (group 1) or of 200 mg/kg L-arginine (group 2) 5 min before the end of ischemia; group 3 (n = 7) received saline pretreatment followed by intravenous injection of saline as a control. Group 1 showed delayed onset of reperfusion compared to the other two groups and a reduction in the rate of the b-wave recovery compared to the control on the 1st day after reperfusion (group 1 vs. group 3; p = 0.0357). The L-arginine posttreatment significantly increased the b-wave recovery (group 2 vs. group 1; p = 0.0005 on day 1 and p < 0.0006 on day 3). The rate of the b-wave recovery in group 1 was inversely proportional to the time to establish complete reperfusion. Inhibition of nitric oxide synthase during the initial phase of reperfusion may worsen the recovery of the b-wave following retinal ischemia, at least in part, by inhibiting establishment of reperfusion.

Animals↗

PubMed1999

Aromatase deficiency caused by a novel P450arom gene mutation: impact of absent estrogen production on serum gonadotropin concentration in a boy.

We identified a new point mutation in the CYP19 gene responsible for aromatase (P450arom) deficiency in a 46,XY male infant with unremarkable clinical findings at birth. This boy is homozygote for a 1-bp (C) deletion in exon 5 of the aromatase gene causing a frame-shift mutation. The frame-shift results in a prematurely terminated protein that is inactive due to the absence of the functional regions of the enzyme. Aromatase deficiency was suspected prenatally because of the severe virilization of the mother during the early pregnancy, and the diagnosis was confirmed shortly after birth. Four weeks after birth, the baby boy showed extremely low levels of serum estrogens, but had a normal level of serum free testosterone; in comparison with the high serum concentration of androstenedione at birth, a striking decrease occurred by 4 weeks postnatally. We previously reported elevated basal and stimulated FSH levels in a female infant with aromatase deficiency in the first year of life. In contrast, in the male infant, basal FSH and peak FSH levels after standard GnRH stimulation tests were normal. This finding suggests that the contribution of estrogen to the hypothalamic-pituitary gonadotropin-gonadal feedback mechanism is different in boys and girls during infancy and early childhood. In normal girls, serum estradiol concentrations strongly correlate with circulating inhibin levels, and thus, low inhibin levels may contribute to the striking elevation of FSH in young girls with aromatase deficiency. In contrast, estradiol levels are physiologically about a 7-fold lower in boys than in girls, and serum inhibin levels remain elevated even though levels of FSH, LH, and testosterone are decreased.

Androstenedione↗

PubMed1999

The effect of immunosuppressive agents (FK-506, rapamycin) on renal P450 systems in rat models.

It is well known that cyclosporin, rapamycin and FK-506 (tacrolimus) are metabolized by the liver microsomal cytochrome P450 enzyme system. Although there have been reports of interaction between these drugs and the renal P450 enzyme system, differences among these immunosuppressants has not been comprehensively demonstrated. We have studied the individual capacities of these immunosuppressants to induce renal microsomal P450 enzymes similar to CYP2B4 and CYP4A2 by examining renal function in treated rats, and have correlated the results by means of biochemical, immunological and immunohistochemical assays of renal P450 enzymes. Cyclosporin caused impairment of renal function with an increase in renal-specific P450 content, but FK-506 and rapamycin did not. Laurate omega- and (omega-1)-hydroxylase activity increased in rats treated with rapamycin but decreased in those treated with FK-506. Prostaglandin A1 (PGA1) omega-hydroxylase activity increased in rats treated with FK-506 but was reduced by treatment with cyclosporin. Aminopyrine N-demethylase activity increased in rats treated with cyclosporin or FK-506, but not in those treated with rapamycin. Western-blot analysis revealed significant induction of P450, (similar to CYP2B4 of the rabbit P450 isozyme) in kidneys from rats treated with cyclosporin but not in those from rats receiving FK-506 or rapamycin. Histochemical studies clearly demonstrated a form of P450 such as CYP4A2 in the proximal tubules of rats treated with cyclosporin, but not in those of rats treated with FK-506 or rapamycin. These results show that although cyclosporin has a strong effect on renal P450 systems and induces such a system in kidney cortex (microsomal P450), FK-506 and rapamycin have no substantial effect on the induction of renal P450. These findings might clarify the nephrotoxicity induced by these immunosuppressive drugs.

Aminopyrine N-Demethylase↗

PubMed1999

[Concomitant mitral valvuloplasty and fenestrated total cavopulmonary connection: a case report].

A seven-year-old boy with tricuspid atresia successfully underwent a fenestrated total cavopulmonary connection and mitral valvuloplasty. Preoperative cardiac catheterization showed a mean pulmonary artery pressure of 16 mmHg. Pulmonary arteriography showed poor development of the branches (PA index: 180). Echocardiography revealed mild to moderate mitral valve incompetence due to prolapse of anterior leaflet. Mitral valve was exposed through the trans-septal approach. The excess chorda length was tucked into a longitudinal split in the top of the posterior papillary muscle. Then wedge resection of the redundant segment of the anterior leaflet and bilateral annuloplasty were performed. Finally, a total extracardiac cavopulmonary anastomosis with a 6 mm fenestration was completed. Postoperative clinical course was uneventful, and he is doing well with no recurrence of mitral incompetence 1 year after the operation.

Child↗

PubMed1999

[A case of post-traumatic autobiographic amnesia].

A 23-year-old woman who was in the ninth month of pregnancy suffered a head injury by falling from the stairs. She regained consciousness in the ambulance car, however, could not recall anything about herself. The morning after, her neurological examination disclosed no abnormal findings. She was alert, spatially oriented, but unable to recall any personal information about herself, her work and family contexts. The results of WAIS-R and WMS were within normal range, and she showed a dissociation between a detailed knowledge of public events and famous people and a complete loss of autobiographic information. EEG and brain MRI were normal. Memory loss spontaneously recovered following several months, and 8 month later, the retrograde amnesia had almost resolved. Although it is well-known that autobiographic amnesia usually attributed to psychogenic etiology, the differential diagnosis of the similar selective retrograde amnesia by organic etiology is important.

Adult↗

PubMed1999

The effect of direct lidocaine injection into the clamped aortic segment on the spinal evoked potential: early diagnosis for spinal cord ischemia.

PURPOSE: The aim of this study was to identify a method to determine whether segmental artery reconstruction was indicated during aortic clamping. METHOD: Spinal cord evoked potential (SCEP) and regional spinal blood flow were studied in 24 adult dogs. Using the left heart bypass technique, aortic clamping divided the aorta into thoracic, abdominal, and terminal segments. After the occlusion of the descending aorta and discontinuation of the perfusion to the abdominal segment, animals were assigned to four groups: no treatment with perfusion to the terminal aorta (group IA), no treatment with cessation of bypass (group IB), 5% lidocaine administration (5 mg/kg) into the abdominal segment with perfusion to the terminal aorta (group IIA), and lidocaine administration with cessation of bypass (group IIB). RESULTS: Cessation of bypass reduced spinal blood flow and SCEP amplitude. Lidocaine injection allowed for a significant rapid decrease in SCEP amplitude in group IIB compared with group IB (24.2% +/- 13.4% versus 92.3% +/- 33.2%; p = 0.0039). The degree of spinal blood supply was reflected immediately in the magnitude of SCEP amplitude change by the direct lidocaine injection. (group IB versus group IIB; p = 0.023). CONCLUSION: The direct injection of lidocaine into the clamped aorta results in a rapidly change in SCEP in the threat of ischemia and can be used to make an early detection of the segmental arteries perfusing to the spinal cord.

Analysis of Variance↗

PubMed1999

Classic Blalock-Taussig shunt in neonates.

BACKGROUND: The choice of palliative procedure for neonates with congenital cyanotic heart defects remains controversial. Several reports have questioned whether the classic Blalock-Taussig shunt is adequate in neonates, because it shows a high rate of mortality and early shunt failure. The purpose of this study is to evaluate the early and late results of classic Blalock-Taussig shunt in neonates. METHODS: From December 1981 to December 1996, 31 neonates underwent a classic Blalock-Taussig shunt. Mean age at operation was 15.9 days (range, 2 to 28 days), and mean body weight was 3214 g (range, 2229 to 4468 g). The major diagnoses were pulmonary atresia with intact ventricular septum (6 patients) and with ventricular septal defect (4), univentricular heart (6), tricuspid atresia (5), tetralogy of Fallot (4), transposition of the great arteries (3), and double outlet right ventricle (3). RESULTS: There were no early deaths. There was one early shunt failure. The patient underwent a replacement of Blalock-Taussig shunt by vascular graft on the 1st postoperative day. Two patients with non-confluent central pulmonary artery underwent a contralateral modified Blalock-Taussig shunt on the 22nd and 42nd postoperative day, respectively. There were two late deaths before the definitive repair was performed. Twelve patients required an additional shunt operation. The mean interval between the initial and the second shunt procedure was 27.7 months (range, 6 to 67 months). Ten patients underwent definitive operation and the mean interval to that procedure was 55.5 months (range, 14 to 121 months). Shunt patency was 94.7+/-5.1% at 3 years. The freedom from cardiac event (cardiac deaths or repeat shunting procedure) was 80.5+/-7.1% at 1 year and 54.9+/-9.4% at 3 years. CONCLUSIONS: The classic Blalock-Taussig shunt has a low operative mortality and has provided excellent long-term palliation in the neonate. We conclude that a classic Blalock-Taussig shunt should be considered a reasonable choice in neonates requiring a palliative procedure for congenital cyanotic heart defects.

Heart Defects, Congenital↗

PubMed1999

[Midterm results of bilateral enlargement of the aortic valve ring for valve replacement].

From 1989, 4 patients underwent bilateral enlargement of the aortic valve ring for valve replacement. Age at the operation ranged from 2 to 8 (mean 6) years; body weight ranged from 14.9 to 25.4 (mean 19.0) kg. This procedure enabled us to implant a prosthesis 3 to 4 sizes larger (19 to 23 mm) than that measured with the native aortic annulus (13 to 17 mm). There was no late death and no cardiac event over a mean follow-up period of 6.2 years. Pressure gradient across the prosthesis measured by echocardiography was 40 mmHg in 1 patient who underwent aortic valve replacement with the use of 19 mm St. Jude Medical valve at 2 years of age. There was no significant pressure gradient in other 3 patients. All patients showed normal left ventricular function. We conclude that bilateral enlargement of the aortic valve ring for valve replacement has provided good midterm results with no mortality and no cardiac event.

Aortic Valve↗

PubMed1999

[A surgical case of right coronary artery-right atrial fistula complicated with postoperative myocardial infarction].

We report a 10-year-old girl with a right coronary artery-right atrial fistula and aneurysm formation. The proximal orifice was closed from the inside of the aneurysm, and the distal orifice through the right atrium under cardiopulmonary bypass. On the 9th postoperative day, myocardial infarction developed due to thrombosis in the fistula stump and the dilated coronary artery. Thrombosis may have been induced by postoperative dehydration and inadequate anticoagulant therapy. It is important to minimize a fistula stump and to strictly administer postoperative anticoagulant therapy.

Arterio-Arterial Fistula↗

PubMed1999

[Management under anesthesia of a patient with renal cell carcinoma extending into the retrohepatic inferior vena cava with the aid of partial cardiopulmonary bypass].

A 70-year-old male with renal cell carcinoma extending into the retrohepatic inferior vena cava was scheduled for radical nephrectomy with vena caval resection under general anesthesia. He had received partial gastrectomy for gastric cancer twelve years before. Computed tomography and inferior vena cavography confirmed that the vena cava was almost completely occluded and that a collateral venous network was well established. It was considered that the surgical approach to the retrohepatic cavals area was technically very difficult, and that there was a high possibility of a pulmonary embolus during the surgical manipulation. To prevent a pulmonary embolus and get good control of the vena cava above the tumor and below the hepatic vein, we decided to use a partial cardiopulmonary bypass (CPB) until the vena cava was clamping above the tumor. Anesthesia was induced with propofol and fentanyl, and maintained with fentanyl and isoflurane-N2O-O2. In the partial CPB blood from the hepatic vein was drained from the inferior vena cava cannula through right atrium, oxygenated by microporus membrane oxygenator, and returned to the left femoral artery. Cannulation to drain the venous circulation entering the vena cava below the tumor was abandoned because the extensive collateral venous network ultimately drains into the superior vena cava. The partial CPB time was 90 min, and the bladder temperature during the CPB was 35-36 degrees C. During the 7.3 hr procedure, the pulmonary embolus did not occur and the total blood loss was 5515 ml. The patient made an uncomplicated recovery and was discharged 30 days after the operation. This newly reported partial-CPB method may be safe and effective for the management under anesthesia of other patients.

Aged↗

PubMed1999

Inhibitory effect of TNP-470 on experimental choroidal neovascularization in a rat model.

PURPOSE: To determine whether an angiogenic inhibitor, TNP- 470 (TNP), an analogue of fumagillin, inhibits choroidal neovascularization (CNV) induced by diode laser photocoagulation in a rat experimental model. METHODS: Fundus laser photocoagulation was performed on Brown Norway rats to induce CNV. In the treatment group, TNP was administered intraperitoneally at the time of laser photocoagulation and on day 7 (50 mg/kg at each time). The incidence of CNV formation was evaluated by fluorescein angiography. The retina was collected from the rats on days 1, 3, 7, and 14 after laser photocoagulation, and semiquantitative polymerase chain reaction (PCR) analyses for the expression of mRNA of basic fibroblast growth factor (bFGF) and vascular endothelial growth factor (VEGF) were carried out. Localization of bFGF mRNA was studied by in situ reverse transcription-PCR (RT-PCR). The numbers of positively labeled cells for bFGF mRNA were compared between the TNP treatment and control groups. RESULTS: The incidence of CNV formation was 22.7% in the TNP-treated rats and that in the control rats was 61.4% (P < 0.001). The semiquantitative PCR analyses showed that bFGF mRNA was upregulated on days 3 and 7 in the control rats, but no significant changes were found in TNP-treated rats. There was no detectable difference in VEGF gene expression between the control and TNP-treated rats. bFGF mRNA was detected by in situ RT-PCR in the regenerated retinal pigment epithelial cells and cells of the outer and inner nuclear layers of the control rats. The number of positive cells for bFGF mRNA in the TNP treatment group was significantly smaller than that of the control group (P < 0.05) on days 3 and 14. CONCLUSIONS: TNP- 470 treatment reduced the incidence of laser-induced CNV formation in this experimental model. The expression of bFGF associated with CNV formation was also significantly reduced by the TNP treatment.

Animals↗

PubMed1999

Caspaselike proteases activated in apoptotic photoreceptors of Royal College of Surgeons rats.

PURPOSE: To study the role of caspase-like proteases, especially roles of more extensively characterized caspase-1 and caspase-2, in apoptotic photoreceptor cell degeneration in Royal College of Surgeons (RCS) rats. METHODS: Both RCS and Sprague-Dawley rats were used. Cryosections of the retinas at various postnatal times were immunostained with antibodies against caspase-1 (interleukin-1beta-converting enzyme, ICE) and caspase-2 (Nedd2/Ich-1). Double staining with TdT-dUTP terminal nick-end labeling (TUNEL), propidium iodide, and the antibodies was also performed. To evaluate the time course of protein expression, western blot analysis was carried out. The temporal profile of caspase-like protease activity was studied using a fluorogenic tetrapeptide substrate, acetyl-tyrosyl-valyl-alanyl-aspartic acid alpha (4-methyl-coumaryl-7-amide) (Ac-YVAD-MCA). Intravitreal injection of a caspase-1 inhibitor, acetyl-tyrosyl-valyl-alanyl-aspartic-aldehyde (Ac-YVAD-CHO), at postnatal days 21 (P21) and P26 was performed to see if this caused a decrease in apoptotic cell number at P28. RESULTS: TUNEL-positive photoreceptors of RCS rats stained strongly with antibodies against caspase-1 and caspase-2. Double staining studies revealed that caspase-1 and caspase-2 were coexpressed in apoptotic cells. Western blot analysis showed that active forms of caspase-1-like and caspase-2-like proteases were upregulated at P28, concurrent with the peak in TUNEL-positive cells. The enzymatic activity of caspase-1-like protease was elevated in RCS rat retinas at P28, and the inhibitor of caspase-1 transiently reduced the number of the apoptotic photoreceptors. CONCLUSIONS: Activation of caspase-like proteases plays an important role in photoreceptor apoptosis of RCS rats.

Animals↗

PubMed1999

[Pneumonitis induced by the drug ougon].

We report a case of drug-induced pneumonitis associated with the herbal medications Sho-saiko-to and Ouren-gedoku-to. A 62-year-old man experienced fever and dry cough after using Ouren-gedoku-to for 2 months. He was admitted to our hospital because a subsequent 5-day course of Sho-saiko-to for suspected bronchitis aggravated these symptoms and caused exertional dyspnea. Chest X-ray films revealed a ground-glass appearance in both lower lung fields. Cessation of these medications improved the patient's clinical and X-ray findings. Bronchoalveolar lavage showed an increase in lymphocytes with a decreased CD 4/CD 8 ratio. While drug-induced lymphocyte stimulation tests gave negative results, challenge tests for Ouren-gedoku-to and Sho-saiko-to were both positive. A diagnosis of drug-induced pneumonitis was made. Our findings suggested the involvement of Ougon, the only common ingredient in the two medications.

CD4-CD8 Ratio↗

PubMed1999

[Hypereosinophilic syndrome associated with antineutrophil cytoplasmic antibody].

A 68-year-old man was admitted to our hospital with complaints of fever, cough, and shortness of breath. He had several erythematous maculae on the trunk and experienced hypesthesia in his lower extremities. Laboratory data showed marked eosinophilia (20,235/mm3) and enhanced hepatobiliary enzymes. Chest X-ray films and computed tomographic scans revealed diffuse patchy infiltrative changes in the lungs. Histologic findings confirmed eosinophilic infiltration of the skin, liver, and lungs. A diagnosis of hypereosinophilic syndrome (HES) was made in accordance with clinical criteria proposed by Chusid et al. The patient was positive for antineutrophil cytoplasmic antibodies (a marker for vasculitis). This suggested a clinical picture resembling Churg-Strauss syndrome (CSS) despite the lack of bronchial asthma. The findings in this report could contribute to a better understanding of the diversity of HES cases, several of which are considered to represent a continuum of pathologies sharing an etiology similar to that of CSS.

Aged↗

PubMed1999

Apoptotic retinal neuronal death by ischemia-reperfusion is executed by two distinct caspase family proteases.

PURPOSE: To evaluate possible roles of caspase-1 and caspase-3 in retinal ischemia-reperfusion injury. METHODS: Retinal ischemia was induced in rats by increasing the intraocular pressure to 110 mm Hg for 60 minutes. Expression of caspase-1 and caspase-3 was studied at the mRNA and protein levels using immunohistochemical staining, western blot analysis, semiquantitative reverse transcription-polymerase chain reaction, and assay of the enzymatic activities. Apoptotic retinal neurons were detected by the TdT-dUTP terminal nick-end labeling (TUNEL) method. To study the roles of the caspases in retinal ischemia-reperfusion injury, an inhibitor of caspase-1, acetyl-tyrosyl-valyl-alanyl-aspart-1-al (Ac-YVAD-CHO; total dose, 10(-7) moles) and that of caspase-3, acetyl-aspartyl-glutamylvalyl-aspart-1-al (Ac-DEVD-CHO; total dose, 10(-7) moles) was injected intravitreally and the number of TUNEL-positive cells was compared with the number in sections not treated with the inhibitors. RESULTS: In the inner nuclear layer (INL), caspase-3-like immunoreactivity was predominantly detected, whereas caspase-1-like immunoreactivity was more predominant in the outer nuclear layer (ONL). Expression of caspase-1 and -3 was upregulated at the protein and gene levels 24 hours after reperfusion. Intravitreal injection of Ac-DEVD-CHO decreased the number of TUNEL-positive cells more significantly in the INL than in the ONL (P < 0.01) at 24 hours, whereas, intravitreal injection of Ac-YVAD-CHO was more effective in decreasing the number in the ONL (P < 0.05). CONCLUSIONS: These findings suggest a possibility that cell-type-specific activation of caspases takes place in retinal ischemia-reperfusion injury, and such caspase may induce retinal neuronal cell death.

Animals↗

PubMed1999

BDNF diminishes caspase-2 but not c-Jun immunoreactivity of neurons in retinal ganglion cell layer after transient ischemia.

PURPOSE: Retinal ischemia-reperfusion injury induces apoptosis of retinal neurons. The purpose of this study was to examine the association of c-Jun, caspase-1, -2, and -3 immunoreactivities and neuronal apoptosis in the retinal ganglion cell layer (GCL) and to study the effects of intravitreal brain-derived neurotrophic factor (BDNF) on the expression of these gene products in a rat model of retinal ischemia-reperfusion injury. METHODS: After 60 minutes of ischemia, eyes were enucleated after 3, 6, 12, 24, and 168 hours of reperfusion. The numbers of c-Jun-, caspase-1-, caspase-2-, caspase-3, and TdT-dUTP terminal nick-end labeling (TUNEL)-positive cells in the GCL were counted. Recombinant human BDNF (5 microg) or vehicle was injected intravitreally immediately after reperfusion. At 6, 24, and 168 hours, the numbers of immunoreactive cells in BDNF- and vehicle-treated groups were compared. RESULTS: Expression of c-Jun and caspase-2 was found in dying cells in flat-mounted retinas. The numbers of caspase-1- and caspase-3-positive cells were fewer than c-Jun- or caspase-2-positive cells. Cell death in the retinal GCL was suppressed by an intravitreal injection of BDNF. The numbers of TUNEL- and caspase-2-positive cells were lower in the BDNF-treated group at 6 hours after reperfusion (P<0.01). The number of c-Jun-positive cells in the treated retinas was not altered by the treatment. CONCLUSIONS: Expression of c-Jun and caspase-2 is associated with neuronal cell apoptosis in the GCL. Suppression of caspase-2 expression may explain the neuroprotective effects of BDNF.

Animals↗

PubMed1999

[New monitoring strategies during shock].

Disturbances in tissue perfusion and oxygenation are known to occur during shock. To treat shock properly, it is necessary to have a good understanding of its pathophysiological characteristics. By monitoring cardiac output and oxygen delivery, we can assess the systemic oxygen transport to the tissues, while mixed venous oxygen saturation provides an index of the systemic oxygen balance between oxygen delivery and consumption. However, because a redistribution of blood volume and flow occurs in shock, the use of systemic monitoring alone does not allow an assessment of regional oxygenation in the various organs. Monitoring of hepatic and jugular venous oxygen saturation enables us to assess the adequacy of regional tissue oxygenation in the liver and brain, respectively, while monitoring intramucosal pH (pHi) is useful not only to assess regional oxygenation in the splanchnic organs, but also to predict complications and to evaluate the clinical outcome. The use of near-infrared spectroscopy may allow simultaneous, noninvasive monitoring of regional tissue oxygenation and energy levels. There exists a wide variety of viable options for the monitoring of shock, both systemically and regionally. This increases the chances of successful treatment.

Brain↗

PubMed1999

Roles of constitutive nitric oxide synthase in postischemic rat retina.

PURPOSE: Nitric oxide is a reactive species that could be protective or destructive to the retina depending on the stage of the evolving ischemic process. This study was conducted to obtain a better understanding of the roles of constitutive nitric oxide synthase (cNOS) during reperfusion after ischemia in rat retina. METHODS: Retinal ischemia was induced for 60 minutes in Sprague-Dawley rats by ligating the optic nerve. Gene expression for endothelial and neuronal nitric oxide synthases (eNOS and nNOS) was studied by reverse transcription-polymerase chain reaction (RT-PCR). To inhibit cNOS, NG-nitro-L-arginine (L-NNA) was injected intraperitoneally four times (every 6 hours) beginning 2 hours after reperfusion, for a total dose of 80 mg/kg. Retinal damage was assessed by the rate of a- and b-wave recovery on electroretinograms and by the thickness of the retinal layers. Retinal circulation and vessel diameter were evaluated by the dye-dilution technique. RESULTS: After ischemia ended, eNOS mRNA initially decreased until 6 hours, then increased to a peak at 12 hours, and decreased progressively beyond 24 hours until the final measurement at 96 hours of reperfusion. nNOS mRNA decreased to nearly undetectable levels during the same measurement periods. L-NNA treatment enhanced reduction of a- and b-wave amplitudes and increased thinning of the inner retina in postischemic eyes. Retinal mean circulation time was markedly prolonged in L-NNA-treated postischemic eyes. Arterial mean transit times were 2.1-fold and 4.5-fold longer in L-NNA-treated postischemic eyes than in L-NNA-treated nonischemic eyes and in D-NNA-treated postischemic eyes, respectively. CONCLUSIONS: This study shows that postischemic inhibition of NOS worsens retinal damage after ischemia-reperfusion and alters postischemic retinal circulation. Nitric oxide may play an important role in protecting the retina from ischemic injury, possibly by preventing postischemic hypoperfusion.

Animals↗