Intraretinal study of cat electroretinogram during retinal ischemia-reperfusion with extracellular K+ concentration microelectrodes

PURPOSE

Intraretinal electroretinograms (ERG) during retinal ischemia-reperfusion were analyzed to clarify which cells are affected in the cat dark-adapted eye.

METHODS

Ischemia was induced by raising the intraocular pressure above arterial systolic pressure in vivo. Double-barreled microelectrodes were used to record the intraretinal ERGs and the light-evoked [K+]o decrease in the subretinal space. Vitreal ERGs, the standing potential and the transepithelial resistance were also recorded.

RESULTS

After 10 minutes of ischemia, vitreal ERG b- and c-waves had recovered fully in 2 hours, and after 30 minutes of ischemia, recovered approximately 85% and 77% of their control amplitudes in 4 hours, respectively. At the early period of reperfusion after 10 minutes of ischemia we observed the supernormal c-wave (124% of its control amplitude, n = 10) with an elevated standing potential. The transepithelial potential (TEP) c-wave increased without changes of slow PIII and transepithelial resistance when the supernormal amplitudes occurred. The light-evoked [K+]o decrease in the subretinal space (90% retinal depth) in the area centralis recovered to about 90% of the control amplitude in 2 hours, and after 30 minutes of ischemia recovered to about 70% of the control amplitudes in 4 hours. The recovery courses of the slow PIII and TEP c-wave were almost the same as that of the light-evoked [K+]o decrease.

CONCLUSIONS

The temporary supernormal amplitude of the ERG c-wave was originated from the retinal pigment epithelium (RPE) during the early period of reperfusion after 10 minutes of ischemia. The photoreceptors, Muller cell and RPE are responsible for the changes in the light-evoked [K+]o decrease, a slow PIII and TEP c-wave, respectively. Intraretinal recordings suggested that after ischemia of 10 to 30 minutes duration, the responses of photoreceptors, Muller cells and the RPE recovered with a similar time course. These findings suggest that in all cases, primarily photoreceptors were damaged.

Differences in the response of genioglossal muscle activity to sustained hypoxia between healthy subjects and patients with obstructive sleep apnea

The depression of EMG activity in upper airway muscles during sleep is known to be a predisposing factor causing upper airway obstruction in patients with obstructive sleep apnea syndrome (OSAS). To clarify whether or not the selective depression of upper airway muscles could be associated with the hypoxic ventilatory depression, we performed sustained hypercapnic hypoxia tests during wakefulness in 11 control subjects and 10 patients with OSAS. Isocapnic sustained hypoxia around SaO2 80% with mild hypercapnia [PETO2: 45.8 +/- 1.6 (SD) and 46.7 +/- 2.8 mm Hg and PETCO2: 44.2 +/- 4.7 and 43.1 +/- 5.0 mm Hg in control and OSAS groups, respectively] was applied for 20 min. Electromyogram activities were recorded from the genioglossal muscle (EMGGG) and diaphragm (EMGDIA) with ventilatory variables. The magnitudes of hypoxic depression in terms of minute ventilation (VI) and minute EMGDIA (EMGDIA/min) were compared in percentage between peak value and the value at the late period. These values were not significantly different between two groups (VI: 79.2 +/- 10.7 and 66.9 +/- 12.8% and EMGDIA/min: 63.2 +/- 17.1 and 60.4 +/- 24.0% in control and OSAS, respectively). On the contrary, the depression in EMGGG was not consistently observed in control (86.1 +/- 38.6% of the peak value) whereas EMGGG was markedly depressed in OSAS (38.6 +/- 15.7% of the peak value; p < 0.01). It is concluded that sustained hypoxia attenuates the activity in genioglossal muscle in patients with OSAS, but not in control subjects.(ABSTRACT TRUNCATED AT 250 WORDS)

Soluble intercellular adhesion molecule-1 (ICAM-1) in sera and bronchoalveolar lavage fluid of patients with idiopathic pulmonary fibrosis and pulmonary sarcoidosis

ICAM-1 plays an important role in inflammatory diseases. To assess level of soluble ICAM-1 in the circulation and inflamed lesions, we measured levels of soluble ICAM-1 in the circulation and bronchoalveolar lavage fluid (BALF) of patients with idiopathic pulmonary fibrosis (IPF) and with pulmonary sarcoidosis (PS) and of healthy volunteers (HV), and we also analysed ICAM-1 expression of BALF cells in some patients and HV. IPF patients had significantly higher levels of circulating ICAM-1 than HV, while PS patients did not. By contrast, significantly increased levels of BALF soluble ICAM-1 were found in PS patients compared with those of HV, but not in IPF patients. There were no significant differences in the proportions of ICAM-1+ BALF lymphocytes in IPF patients, PS patients and HV, whereas significantly increased proportions of ICAM-1+ pulmonary alveolar macrophages were found in PS patients compared with those of HV, but not in IPF patients. There was a significant positive correlation of BALF soluble ICAM-1 levels to BALF lymphocyte proportions in PS patients. Although the source of BALF soluble ICAM-1 is unclear, BALF soluble ICAM-1 appears to reflect the grade of local activity of sarcoidosis. An interesting discrepancy between soluble ICAM-1 levels in the circulation and BALF was found in IPF patients, and this might be an important clue to an understanding of this disorder.

A seroepidemiological study of hepatitis C virus (HCV) in an area with a high prevalence of chronic liver disease in the Kyushu district of Japan

The incidence of hepatitis virus type C (HCV) in an area, Futase, of Iizuka city in Chikuho province in the northeastern part of Fukuoka prefecture in Kyushu, Japan, was estimated by screening sera for anti-HCV antibodies. Titers of anti human T-lymphotropic virus type I (HTLV-I) antibodies and hepatitis virus type B surface antigens (HBs) were also determined. The area of the present study is known to have a particularly high prevalence of chronic liver diseases, because coal mining was the key industry until a few decades ago. Also, in the old days it was rather isolated from the neighboring vicinities by surrounding mountains. The subjects of the present survey were 310 patients (117 males and 193 females) with various chronic diseases who visited Futase Social Insurance Hospital during a two year period from 1991 to 1992. Anti-HCV antibodies were detected in the sera of 55 patients, which is an overall positive rate of 18% (26% in male and 14% in female patients). This is extremely high compared to an estimated nationwide average positive rate of 1.6%. Even in 270 patients with normal liver function, the incidence was as high as 10%. The incidences were particularly high in groups of patients aged 40 through 49, 50 through 59 and 60 through 69, ranging from 20 to 23%, while they were as low as 13 and 17% in those aged 70 through 79 and 80 through 89 years, respectively. A high incidence, 57% was estimated for the patients with impaired liver function due to chronic liver diseases, especially in those concomitantly having diabetes mellitus (DM), 91%. The incidence of anti-HCV antibodies was the highest, 100%, in patients having both liver cirrhosis (LC) and DM. This was followed by those having chronic hepatitis (CH) and DM concomitantly and by those with LC alone, 86% each, and by those with CH alone 44%. Furthermore, the genotypes of the HCV in the sera of nine randomly selected carrier patients who had anti-HCV antibodies, even though they had diseases other than hepatic diseases and their liver functions were normal, were examined by the polymerase chain reaction method employing type-specific primers for DNA amplification. As a result, all the HCV strains were type II. On the other hand, there were no apparent differences in the incidences of HTLV-I in the area of the present study and in neighboring provinces of the same prefecture, Fukuoka.(ABSTRACT TRUNCATED AT 400 WORDS)

Phagocytic ability of polymorphonuclear cells and macrophage is not decreased in aged bed ridden patients

The phagocytic ability of polymorphonuclear cells and macrophages from aged, bed ridden patients was investigated. Phagocytosis of carbon in aged bed ridden patients did not differ from that of young controls, and extent of upregulation of granulocytes phagocytosis in response to elevation of incubation temperature was also similar between the two groups. Morphological changes of macrophages in response to ingestion of colloidal carbon was more prominent in young controls. These data suggest that a depressed phagocytosis is not an important factor in the increased susceptibility to infections of aged bed ridden patients, although the reactivity of macrophages may be more closely related to the infection defence.

Effects of intravenous superoxide dismutase and catalase on electroretinogram in the cat postischemic retina

We examined the effects of the antioxidant enzymes, 10,000 U/kg of superoxide dismutase (SOD) and 50,000 U/kg of catalase (CAT) on cat electroretinograms during the reperfusion after retinal ischemia. The intravenous administrations of SOD and CAT promoted the recovery of the c-wave after 30 min of ischemia but not the b-wave. At 5 min after onset of reperfusion, SOD- and CAT-treated eyes showed 90 and 110% recovery of the c-wave amplitude respectively, against 50% recovery in the untreated eyes. These results suggested that the oxygen-derived free radicals affected the retinal pigment epithelium at the early period of reperfusion.

Poly(vinyl alcohol) hydrogels as soft contact lens material

A new type of soft contact lens was developed from the poly(vinyl alcohol) (PVA) hydrogel prepared by a low temperature crystallization technique using a water-dimethyl sulfoxide mixed solvent. The PVA contact lens materials had a water content of 78% and a tensile strength of 50 kg/cm2, five times as strong as that of commercial poly(2-hydroxyethyl methacrylate) soft contact lens. The amount of proteins adsorbed to the PVA soft hydrogel material was half to one thirtieth of that of conventional soft contact lenses. Histological and scanning electron microscopic observation of rabbit eyes which had worn the PVA soft contact lens for 12 weeks showed no difference in corneal epithelium and cell arrangement in the corneal epithelium from the non-wearing eyes.

Acute myelopathy and cerebellar signs associated with uveitis with positive serum and cerebrospinal fluid antibodies to HTLV-I

A 55-year-old man was admitted because of weakness in the legs of a few days duration. Neurological examination revealed paraparesis, ataxia of the left limbs, superficial hypoesthesia below the T-10 dermatome level and urinary retention. The antibody titers to human T-lymphotropic virus type I (HTLV-I) were x640 in the serum and x16 in the cerebrospinal fluid (CSF). The HTLV-I gag proteins, p19, p24, p46 and p53 were identified by Western blotting analysis of the serum and CSF. The CSF contained 691 white cells/c.mm; protein, 260 mg/dl; IgG, 84 mg/dl; and IgG index, 2.49. Although the paraparesis and urinary retention disappeared within 10 days, he developed right uveitis which responded well to corticosteroid treatment. With improvement of the sensory impairment, cerebellar signs and CSF pleocytosis as well as uveitis, he was discharged eight weeks after admission. HTLV-I uveitis is a recently established disease entity. The case emphasizes the need to test blood and CSF for HTLV-I antibodies if patients developed myelopathy and cerebellar signs of acute onset, especially when associated with uveitis.

Vector analysis of corneal astigmatism after scleral buckling surgery

We conducted a short-term prospective study of 125 eyes with retinal detachment to examine changes of corneal astigmatism about 2 weeks after scleral buckling surgery, using a vector method on 2-fold-angle rectangular coordinates. Segmental buckles of one to less than two quadrants produced significantly greater changes in astigmatism (1.65 +/- 0.97 dptr) than those of less than one quadrant (0.88 +/- 0.75 dptr) and those spanning two quadrants or more (1.09 +/- 0.38 dptr) (p = 0.0005, Kruskal-wallis test; n = 73). The amplitude of differential vectors after explant buckling surgery (1.33 +/- 0.89 dptr, n = 24) was significantly greater than after implant buckling surgery (0.65 +/- 0.45 dptr, n = 15) (p = 0.009, Mann-Whitney U-test) with buckles of one quadrant or less. Differential vectors tended to direct toward the buckles. There was no obvious directional tendency in the case of encircling procedures (n = 52).

Effects of the new calcium antagonist monatepil on cardiac function and myocardial oxygen supply and demand in animals

The effects of monatepil ([(+/-)-N-(6,11-dihydrodibenzo[b,e]thiepin-11-yl)-4-(p-fluor ophenyl)-1- piperazinebutyramide]maleate, AJ-2615, CAS 103377-41-9), a new calcium antagonist, on cardiac function and myocardial oxygen supply and demand were examined. 1. Monatepil reduced the spontaneous beats of isolated rabbit atria at the concentration of 3 x 10(-6) and 10(-5) mol/l. Monatepil decreased the contractile force of papillary muscles in a concentration-dependent manner (3 x 10(-8)-10(-5) mol/l). 2. Monatepil (0.3 mg/kg i.v.) slightly decreased heart rate in anesthetized open-chest dogs. This drug (0.1, 0.3 mg/kg i.v.) increased cardiac output and decreased blood pressure and total peripheral resistance. Monatepil decreased left ventricular dP/dtmax and slightly increased left ventricular end-diastolic pressure. 3. Monatepil (0.1-1.0 mg/kg i.v.) did not affect the PR interval, QRS duration and QTc interval of electrocardiograms in anesthetized dogs, whereas diltiazem (0.3 and 1.0 mg/kg i.v.) markedly prolonged the PR interval. 4. Monatepil (0.1-0.3 mg/kg i.v.) increased coronary blood flow (CoBF) and decreased myocardial oxygen consumption (MOC) and extraction. 5. Monatepil and diltiazem showed almost the same effects on cardiac function and myocardial oxygen supply and demand, but the negative chronotropic and negative dromotropic effects of monatepil were less potent than those of diltiazem.

Wegener's granulomatosis with rapidly progressive retinitis and anterior uveitis

A case of a Wegener's granulomatosis with severe retinitis and anterior uveitis is presented. The diagnosis of Wegener's granulomatosis was based on the clinical features and on histologic findings of multiple lesions. Anterior uveitis and severe retinitis developed in both eyes, resulting in decreased visual acuity. This case indicates that thorough examinations of the ocular fundus should be performed routinely during the follow-up of patients with Wegener's granulomatosis.

The effect of hypoxic depression on genioglossal muscle activity in healthy subjects and obstructive sleep apnea patients

We investigated whether selective depression of the genioglossus muscle (GG) activity could be associated with hypoxic ventilatory depression, which is developed in the late phase of the biphasic ventilatory response during sustained hypoxia. Eleven control subjects and 10 patients with obstructive sleep apnea syndrome (OSAS) were examined by an isocapnic sustained hypoxia test for 20 minutes. Ventilatory parameters and electromyographic (EMG) activities were recorded from GG (EMGGG) and diaphragm (EMGDIA). Hypoxic depression in minute ventilation (V1) and EMGDIA occurred when compared between the peak value and the value at late period in both groups. On the contrary, depression in EMGGG was not observed in controls (86% of the peak value), whereas EMGGG was strikingly depressed in OSAS (39% of the peak value). We conclude that sustained hypoxia reduces the activity of GG in OSAS, but not in control subjects. These data suggest that the lack of a compensatory response of GG to sustained hypoxia is possibly responsible for the pathogenesis of OSA.

Effects of 100% O2 exposure on hypoxic ventilatory response

Comparison of the slope of progressive isocapnic hypoxia obtained with and without prior O2 exposure (termed + and -O2 runs, respectively) placed our subjects into two groups. Positive responders had a significantly lower slope in -O2 runs compared with similar runs in negative responders, but they also improved hypoxic ventilatory response (HVR) significantly after O2 exposure. Negative responders had a high -O2 slope that did not alter significantly after O2 exposure. We conclude that ambient air hypoxic depression is active in positive responders who are O2 sensitive.

Variability of integrin alpha 2 beta 1 activity on human platelets

The activity and surface antigenicity of alpha 2 beta 1 on platelets from 27 normal subjects were found to vary significantly. A fourfold range of surface antigen correlates with a 20-fold variation in the ability of nonactivated, washed platelets to adhere to type I collagen and a fivefold variation in the adhesion of platelets to type III collagen. These differences in surface receptor are reflected in significant variation in the lag time required for type I collagen-induced platelet aggregation in platelet-rich plasma. Among the same individuals, no difference was observed in surface levels or activities of two other platelet integrins, the fibronectin receptor alpha 5 beta 1 and the fibrinogen receptor alpha IIb beta 3. In all cases studied, we observed complimentary differences in the incorporation of 125I into surface alpha 2 beta 1, in quantity of surface alpha 2 beta 1 antigens, and in alpha 2 beta 1 collagen receptor activity. Despite variations in these parameters, there was no difference in the electrophoretic mobility or isoelectric point of either integrin subunit among the individuals studied. The wide range of activity and antigenicity of this platelet collagen receptor may result from polymorphism(s) in the alpha 2 beta 1 genes, or the activity of alpha 2 beta 1 may be variably regulated by another gene product. The heterogeneity of platelet alpha 2 beta 1 that we describe in this report certainly explains previous discrepancies concerning the contributions of this integrin to platelet adhesion to collagens. Most importantly, differences in surface collagen receptor activity may correlate with a long-term risk toward thrombosis, impaired hemostasis, and/or cardiovascular disease.

A base-paired hairpin structure essential for the functional priming signal for DNA replication of the broad host range plasmid RSF1010

The two single-strand DNA initiation signals, ssiA(RSF1010) and ssiB(RSF1010) of the broad host-range plasmid RSF1010 contain proposed stem-loop structures. Nine single base-change mutations in the stem of the ssiA structure, each of which destroyed a relevant base pairing, damaged the ssiA activity. A second single-base change was introduced into each of the nine ssiA mutants in such a way that the base pairing was restored. Only three out of nine second base changes that restored the base pairing restored the ssiA activity up to the wild-type level. Thus, the three are intramolecular suppressors. The results strongly suggested that, in the area of the stem of ssiA where the suppressor mutations fell, base pairing was the most important structural parameter for the ssiA activity. By contrast, it is most probable that, in the other part of the stem of ssiA, both base-pairing and the intrinsic base sequence were the major determinants of the ssiA activity.

Mortality patterns among men in the motor vehicle manufacturing industry

This retrospective follow-up study evaluates the mortality experience of 123,232 male hourly workers employed at a motor vehicle manufacturing company in 1973. Company computerized personnel records were used to identify subjects and to obtain their employment history. Follow-up through December 31, 1985 was conducted using company, state, and national data sources. The mortality rates of the cohort were compared with the rates of the United States (U.S.) general population of white or black men, adjusting for age and calendar time, and using the standardized mortality ratio (SMR) as the measure of association. The overall mortality rate of cohort members is lower than the U.S. rate by 11% among whites (11,060 observed/12,427 expected deaths; SMR = 89) and by 24% among blacks (3,744/4,926 deaths; SMR = 76). These low mortality rates reflect deficits of diseases other than cancer. Cancer SMRs are 99 for whites and 90 for blacks. There are slight excesses of stomach cancer (SMR = 113) and of lung cancer (SMR = 108) among whites and of cancer of the large intestine and rectum (SMR = 114) and of the lymphopoietic tissue (SMR = 111) among blacks. Both whites and blacks have a large deficit of buccal cancer and pharynx cancer, and blacks also have a deficit of esophagus cancer. The cohort's overall deficit of deaths is due largely to the favorable mortality experience of active workers. In contrast, white subjects who have left active employment have an 11% mortality excess, and inactive black subjects have a mortality rate that is similar to the general population rate. The increased mortality among inactive whites is not limited to any one particular disease category. This pattern may reflect illness-related employment termination and generalized confounding by socioeconomic status, although the study does not rule out a relationship between workplace exposures and specific diseases.

Retrospective follow-up study of foundry and engine plant workers

A retrospective follow-up study of 21,013 workers employed at a foundry and two engine manufacturing plants was conducted to determine if these workers had an unusual mortality experience. A total of 2,235 deaths occurred during the follow-up period of 1970-1987. Mortality from all causes was lower than expected. Men experienced a 6-13% excess of lung cancer deaths, depending on the choice of the comparison group. The data displayed evidence of a positive trend between lung cancer mortality and increasing duration of employment (p = 0.008). White men experienced a statistically significant excess of deaths from stomach cancer (standardized mortality ratio [SMR] = 158; 95% confidence interval [CI] = 101-234). Black men had increased mortality from pancreatic cancer, especially among engine plant workers (SMR = 303; CI = 121-624), and an excess of prostate cancer, concentrated among foundry workers (SMR = 234; CI = 112-430).

[Clinical features of measles pneumonia in adults: usefulness of computed tomography]

The clinical features, chest radiographs and computed tomographic (CT) images were evaluated in 11 cases with serologically proved adult measles complicated with pneumonia (10 were previously healthy and one had sarcoidosis). Pneumonia appeared during the rash period in all cases. Respiratory symptoms were cough (9/11), dyspnea (3/11), and hypoxemia (10/11). Pneumonia manifestations were detected in only 4 cases by chest radiograph; on the other hand, they were seen in all cases by CT scan and consisted of ground-glass opacities (73%), nodular opacities (64%) and consolidation (27%). CT seems to be a useful method to detect measles pneumonia if it is suspected. Measles pneumonia in previously healthy patients had a good prognosis, as the hypoxemia disappeared within 6 days in all cases. The sarcoidosis patient showed prolonged pneumonic shadows and period of hypoxemia. Measles pneumonia occurring in a host with cellular immunodeficiency may have a severe clinical course.

[The long term results of hyperbaric oxygen treatment for macular edema with retinal vein occlusion]

We retrospectively evaluated the effect of hyperbaric oxygen treatment on seventy-nine eyes of seventy cases with cystoid macular edema secondary to retinal vein occlusion. Twenty-three eyes had central retinal vein occlusion (CRVO), and fifty-six eyes had branch retinal vein occlusion (BRVO). Visual acuity improved by two lines or more in 40 eyes (17%) with BRVO, and in 10 eyes (44%) with CRVO immediately after the therapy. Six months or more after treatment, visual improvement persisted in 14 of 30 BRVO eyes (47%), and in only one of 11 CRVO eyes (9%). CRVO showed poor prognosis in the long term compared with BRVO. We speculated that activation of aerobic metabolism might be more important than reduction of vascular hyperpermeability as the therapeutic effect of hyperbaric oxygen, and that hyperbaric oxygen might mainly affect the retinal cells in the marginal zone of the ischemic retina in the macular region.

Management problems in continuous care of male patients with mild hypertension with special reference to alcohol-intake

Forty two male patients with borderline and mild hypertension were followed up for 3.9 years without medication. During this period, all subjects had nonpharmacological interventions including salt restriction, weight reduction, anti-smoking or anti-alcohol instruction, and physical exercise after the established protocol. Comparisons of biomedical data between pre- and post-observation revealed no significant improvements. Although the smoking habit decreased during this period, the drinking habit rarely changed and even significant increase of the total amount of alcohol ingestion was observed. These data indicate great limitation of nonpharmacological intervention in the care of these asymptomatic hypertensive patients for a lifelong base.

Identification of the alpha-subunits of rod and cone transducin in chicken photoreceptor cells

The chicken retina has several types of cone photoreceptor cells, each of which contains a visual pigment, chicken red (iodopsin), green, blue or violet. Although biochemical and photochemical properties of these cone pigments have been well characterized, no information is available about the chicken photoreceptor G-protein, transducin, which couples with the visual pigment to convert a photon signal into a cellular response. To identify alpha-subunits of chicken rod and cone transducins (Tr alpha and Tc alpha, respectively), we produced two site-directed antibodies which discriminate between bovine Tr alpha and Tc alpha. Immunohistochemical studies on chicken retinas revealed that the antibody against bovine Tr alpha specifically stained the rod outer segments. On the other hand, the antibody against bovine Tc alpha uniformly stained the outer segments of the double cones and all types of single cones, while the single cones were immunohistochemically classified into three types by using a combination of antibodies against bovine rhodopsin and chicken iodopsin. Immuno-blot analyses demonstrated that the antibody against Tc alpha recognized a single band of chicken photoreceptor protein, whose molecular weight (42,000) was in good agreement with that of bovine Tc alpha (41,000). The antibody against Tr alpha recognized a protein having the same molecular weight as that of bovine Tr alpha (39,000). These observations strongly suggested that all types of chicken cone cells have a single common Tc alpha (42 kDa) structurally related to bovine Tc alpha, though each cone cell type has a distinct visual pigment.

Evaluation of idiopathic epiretinal membranes by a scanning laser ophthalmoscope

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