Biomedical subjects

M Horiguchi

Publications and source records attributed to M Horiguchi.

At least 55 records · Page 3Linked to original sources

PubMed1998

Parameters of lymphocyte Na+-Ca2+ regulation and blood pressure: the gender effect.

Alterations in cellular Ca2+ and Na+ regulation play a role in the pathogenesis of essential hypertension. Using peripheral lymphocytes from 68 normal persons, we observed the following relationships for major cellular Ca2+ regulatory parameters. Among men and women, Na+-Ca2+ exchanger activity was positively correlated with the resting cytosolic free Ca2+ ([Ca2+]c) (r=0.43, P=0.0003), and the resting [Ca2+]c was positively correlated with cytosolic Na+ ([Na+]c) (r=0.50, P=0.0001). For men only, store-operated Ca2+ entry was positively correlated with Na+-Ca2+ exchanger activity (r=0.63, P=0.0001). In addition, systolic and diastolic blood pressures were positively correlated with [Na+]c in men (r=0.53, P=0.001, and r=0. 41, P=0.017, respectively) but not in women (r=0.30, P=0.088, and r=0.24, P=0.17, respectively). Some of the relationships between cellular and blood pressure parameters were confounded by serum triglycerides. These observations indicate a gender effect on cellular Ca2+-Na+ regulation and its relationship with blood pressure.

Adult↗

PubMed1998

Recording multifocal electroretinogram on and off responses in humans.

PURPOSE: To record the on and off responses of the multifocal photopic electroretinogram (ERG) from the human retina and to explore how each ERG component (a-, b-, and d-waves) changes at different retinal eccentricities. METHODS: Multifocal ERGs were recorded with the visual evoked response imaging system. Sixty-one densely packed stimulus elements were square wave-modulated between stimulus on and stimulus off, according to a binary m-sequence at a rate of 4.7 Hz under a constant background illumination. The ERGs were recorded with a bipolar Burian-Allen bipolar contact lens electrode from five normal subjects. Response densities (amplitude per retinal area) were calculated for five different eccentric rings. RESULTS: The response densities for all components (a-, b-, and d-waves) decreased with increasing retinal eccentricities. The ratio of the d-wave to b-wave amplitudes was minimal in the central retina and increased toward the periphery. The ratio of a-wave to b-wave amplitudes also increased toward the peripheral retina. CONCLUSIONS: These results demonstrate that the on and off responses of the human cone ERGs have different spatial distributions across the human retina, and they suggest a change in the photopic retinal circuitry with increasing retinal eccentricities.

Adult↗

PubMed1998

[A case of the double mitral valve orifices].

In 1996 student course of gross anatomy dissection at Iwate Medical University School of Medicine, a case of the double mitral valve orifices was found in a heart of a 73-year-old male cadaver who died of acute pneumonia. No other congenital anomalies were detected in this heart. There was no prior history of heart disease. The left atrioventricular ostium was an oval with a long axis of 4 cm and a short axis of 2.5 cm. There were double mitral valve orifices, main and accessory (Fig. 1). The main orifice situated left ventrally with a long axis of 2.5 cm and a short axis of 1.7 cm, had a larger cleft. The accessory orifice situated right dorsally with a long axis of 2.5 cm and a short axis of 1.2 cm, had a smaller cleft. There was a bridge-like valvular leaflet between the two clefts (Fig. 1). Disregarding small incisions, both the main and the accessory mitral valves had two cusps, anterior and posterior. The anterior and posterior cusps of the main and accessory valves were continuous and considered to be homologous with the anterior and posterior cusps of the normal mitral valve. In other wards, this double mitral valve orifices was appeared to be formed by bridging the cleft between the anterior and posterior cusps of the normal mitral valve. The valvular cusps of the main or the accessory mitral valve had proper chordae tendineae and papillary muscles. The papillary muscles were classified into four groups, anterior (A), anterolateral (AL), posterior (P) and posterolateral (PL) according to Taniya (1974). The anterior papillary muscles group had a base at the anterior wall of the left ventricle, the anterolateral papillary muscles group had at the whole lateral wall, the posterior papillary muscles group had at the boundary between the interventricular septum and the posterior wall, and the posterolateral papillary muscles group had at the posterior part of the lateral wall (Fig. 3). The anterior and anterolateral papillary muscles groups, and the posterior and posterolateral papillary muscles groups of Taniya (1974) constituted the anterior and the posterior papillary muscles respectively in the general use of the anatomical term. The chordae tendineae attached to the cusps of the main orifice arose from the anterior, anterolateral and posterior papillary muscles groups (Fig. 2a). And those attached to the cusps of the accessory orifice arose from the posterolateral papillary muscles group (Fig. 2b). The chordae tendineae were also classified into three types after Taniya (1974). The A type chordae tendineae were thick and attached to the base of the cusps, the type B were moderately thick and attached to the midway between the base and the margin of the cusps, and the C type were thin and attached to the margin of the cusps. The main mitral valve had 6 type A, 8 type B and 40 type C chordae. The accessory mitral valve had 0, 6 and 30 chordae respectively (Fig. 2). This case of the double mitral valve orifices is considered to be included in the central type of Cascos et al. (1967) and the bridge type of Elfenbein et al. (1967). A morphogenetic mechanism of this type of the double mitral valve orifices is explained by an abnormal adhesion between the dorsal endocardial cushion and the left lateral endocardial cushion like mass in early developmental stage according to Wimsatt and Lewis (1948). But a possibility of an abnormal orifice in the posterior cusp which is produced in the process of formation of cusps, chordae tendineae and papillary muscles in later stage, still remains to be discussed.

Aged↗

PubMed1998

[Re-evaluation of the human brachialis muscle by fiber analysis of supply nerves].

The nerve supply to the human brachialis muscle has been investigated by many researchers with gross anatomical and/or microdissectional methods. It has been made clear that the brachialis muscle is innervated by two groups of nerve branches, that is, branches from the musculocutaneous nerve innervating most of the muscle and those from the radial nerve innervating the small inferolateral part. However, the constancy of the radial nerve supply is controversial. Furthermore, some researchers have reported a median nerve supply. On the other hand, the morphological meaning of the double nerve supply by the musculocutaneous nerve from the anterior division of the brachial plexus and by the radial nerve from the posterior division has been generally explained to be a result of the fusion of two muscular primordia, one from the ventral (flexor) premuscular mass and the other from the dorsal (extensor) premuscular mass. The inferolateral part of the brachialis muscle has been considered as a detached portion of the brachioradialis muscle. In contrast with this view, there also has been another view that the brachialis muscle has only one origin from the ventral premuscular mass. The branch from the radial nerve derives from the anterior division of the brachial plexus and uses the radial nerve only as a route to the brachialis muscle by unknown mechanisms. However, the latter view has shown no reliable evidence. Therefore, the purposes of this study are 1) to obtain reliable evidence concerning the anterior derivation of nerve fibers of the branch from the radial nerve (by teasing fibers), 2) to make clear the topographical relationship between the nerve fibers from the musculocutaneous nerve and those from the radial nerve in the brachial plexus (by teasing fibers) and in the brachialis muscle (by an investigation of intramuscular nerve supply) and 3) the topographical relationship between nerve fibers to the brachialis muscle and those to the brachioradialis muscle (by teasing fibers), and 4) to investigate the constancy or the incidence of the radial and median nerve supply. Materials used were sixteen human arms of ten cadavers from the 1996 student course of dissection at Iwate Medical University School of Medicine. Two groups of nerve branches innervating the brachialis muscle, one from the musculocutaneous and the other from the radial nerves, were dissected by a gross anatomical method. The best dissected three specimens were used for the fiber analysis (teasing fibers) of the branches to the brachialis and brachioradialis muscles from the branching points to the nerve roots of the brachial plexus and the investigation of the intramuscular nerve supply in the brachialis muscle. The fiber analysis and investigation of the intramuscular nerve supply were done using an operational microscope (Zeiss, 6-H). The results were as follows: 1) The radial nerve supply to the brachialis muscle was constantly observed (the incidence was 16/16), but no median nerve supply was seen. 2) The branch from the musculocutaneous nerve supplied most part of the brachialis muscle except for the small inferolateral part of the muscle supplied by the radial nerve branch. 3) Communications between the two nerve sources were observed in the brachialis muscle in all three cases. 4) Nerve fibers composing the branch from the musculocutaneous nerve derived from the anterior divisions of the ventral rami of the fifth and sixth cervical nerves. 5) Nerve fibers composing the branch from the radial nerve derived from the anterior divisions of the ventral rami of the sixth and seventh cervical nerves, and were situated in the same bundle of fibers with those from the musculocutaneous nerve at the sixth cervical nerve in the first and third cases (right side of the first and second bodies). 6) Nerve fibers composing the branch to the brachioradialis muscle ran in the same bundles with those to the brachialis muscle in the radial nerve, but were situated in the

Forearm↗

PubMed1998

Effect of glutamate analogues and inhibitory neurotransmitters on the electroretinograms elicited by random sequence stimuli in rabbits.

OBJECTIVE: To study the origin of the different components of the electroretinogram (ERG) elicited by a random binary m-sequence stimulus. METHODS: Electroretinograms were recorded from pigmented rabbits before and after the injection of glutamate analogues (2-amino-4-phosphono-butyric acid [APB; DL form] and cis-2,3-piperidine-dicarboxylic acid [PDA]) and inhibitory neurotransmitters (glycine and gamma-aminobutyric acid [GABA]) to abolish the contribution of different cell types to the ERG. Two types of stimuli were used: conventional full-field stimulation with short- and long-duration flashes and a random binary m-sequence of flashes designed to mimic the pseudorandom binary m-sequence stimulation used in the multifocal ERG technique. RESULTS: The effects of APB and PDA on the first-order kernel of the random ERGs were similar to those on the photopic short-flash ERG. Glycine and GABA minimized the oscillatory potentials (OPs) of the photopic ERGs, and also reduced the amplitude of the positive wave of the first-order kernel slightly but caused a large reduction in the amplitude of the second-order kernel. CONCLUSIONS: The data suggest that the ON and OFF bipolar cells contribute significantly to the photopic short-flash ERG, as previously shown, and to the first-order kernel of the responses elicited by the pseudorandom binary sequence stimuli. The second-order kernel and the OPs receive a strong contribution from the cells of the inner retinal layers.

Aminobutyrates↗

PubMed1998

The human gemelli muscles and their nerve supplies.

The superior and inferior gemellus muscles were examined as to their forms and the patterns of nerve supply in 13 human cadavers (20 specimens). The superior gemellus muscle (Gs) was absent in 3 specimens, but showed no accessory slip or fusion with the internal obturator muscle (Oi). The nerve to the Gs originated from the nerve to the Oi (OiN) in 7, the nerve to the quadratus femoris muscle (QfN) in 4, or both in 6 specimens. The inferior gemellus muscle (Gi) was present in all, but fused with the Oi in 3 specimens. In one specimen, an accessory muscle bundle was observed between the Gi and Oi. The Gi always received branches from the QfN at its anterior surface, but received an additional nerve supply at its posterior surface from the OiN or the pudendal nerve in one specimen each, and the accessory bundle was supplied by a branch from the OiN at its posterior surface. In a well preserved specimen, a branch to the Gi from the QfN entered the Oi and communicated with the OiN after supplying and leaving the Gi. The frequency of the dual innervation of Gs by the OiN and QfN was 29.3%, but that of the Gi and Oi could not be determined, because of the occurrence of the fused part, the accessory bundle and nerve communication. There existed some gross anatomical differences between both gemelli muscles; they are considered to be parts of the internal obturator muscle in a broad sense.

Humans↗

PubMed1997

Species differences between chickens and rats in chemical properties of adipose tissue lipoprotein lipase.

Chemical characterization of chicken and rat lipoprotein lipase (LPL) was carried out following purification of LPL. Molecular weight and isoelectric point of both purified enzymes were determined to be 60 KDa and pH 4, while optimum temperature and pH to yield the maximal activity were about 37 degrees C and pH 8.5. Metallic ions, NaCl and protamine sulfate reduced, and heparin increased, both LPL activities. Michaelis constants for LPLs determined with triolein emulsion as the substrate were 0.98 and 1.57, and those of Vmax were 379.2 and 181.3, in chickens and rats, respectively. Triton WR-1339 caused mixed-type inhibition in rat, but inhibited chicken LPL noncompetitively. In LPLs of chickens and rats, values of Ki were 66.7 and 36.4 with triolein emulsion as the substrate, and 832.4 and 66.0 with respective VLDL as the substrate. These results show species difference between chickens and rats in the affinity to lipoproteins of LPL and inhibition of LPL by Triton WR-1339.

Adipose Tissue↗

PubMed1997

Persistent primitive sciatic artery associated with other various anomalies of vessels.

A left persistent primitive sciatic artery was observed in a Japanese male cadaver. The sciatic artery arose from the internal iliac artery and perforated the ventral division of the sacral plexus. The sciatic artery did not anastomose with the perforating arteries nor the popliteal artery. The left femoral artery was incompletely developed, attenuating and terminating as the saphenous artery. Instead of the femoral artery, direct continuation of the profunda femoris artery, which probably corresponded to the fourth perforating artery, became the popliteal artery. Other vessel anomalies were observed in various regions. They included; (1) the retroesophageal right subclavian artery; (2) the left vertebral artery entering the transverse foramen of the 4th cervical vertebra; (3) bilateral occurrence of the superficial brachial artery; (4) the left gastric artery independently arising from the abdominal aorta; (5) a hepatolienomesenteric trunk; (6) three accessory renal arteries; (7) double testicular arteries; (8) the arteria intermesenterica; (9) a venous ring termed the 'renal collar', and (10) paired thoracic ducts. The present cadaver was considered to be a very rare case in which many primitive vascular systems had extensively persisted in various parts of the body.

Abnormalities, Multiple↗

PubMed1997

Recording multifocal electroretinograms with fundus monitoring.

PURPOSE: To record multifocal electroretinograms (ERGs) with simultaneous fundus monitoring. METHODS: An infrared television fundus camera was used to monitor the fundus. A tightly packed array of 19 yellow light-emitting diodes (LEDs) was used as the stimulus source and LEDs were alternated between on and off according to a binary m-sequence at a rate of 75 Hz. The stimulus array subtended approximately 25 degrees of the visual angle. Multifocal ERGs were recorded with a Burian-Allen bipolar contact lens electrode from two normal subjects and a patient with macular dystrophy. RESULTS: When the center of the stimulus was positioned on the fovea, the amplitude of the response was largest at the fovea and decreased toward the peripheral retina; the response pattern corresponded to the spatial distribution of cone cells. When the center of the stimulus was positioned on the optic disc, the response at the optic disc was undetectable. A reliable multifocal ERG was obtained from a patient with macular dystrophy. CONCLUSIONS: This system made it possible to monitor the stimulus on the fundus and to adjust the stimulus to the correct retinal locations with exact focusing. The authors' findings indicate that this method especially can be useful in patients with poor fixation. In addition, the authors' results suggests that the stray light effect in the multifocal stimulus system is minimal if any.

Adult↗

PubMed1997

[Indocyanine green angiography in Stargardt's disease].

We performed indocyanine green angiography (ICG angiography) and fluorescein angiography in order to investigate the choroidal circulation in patients with Stargardt's flavimaculatus. Eight eyes of 4 patients in Groups 2 approximately 3 (Noble classification) were included in this study. In the area with "dark choroid" in fluorescein angiography, ICG angiography revealed large choroidal vessels in all eyes, but some fluorescent choroidal vessels were dark around the atrophic macula and in the peripapillary area, which indicated a greater storage of lipofuscin within the retinal pigment epithelium in those areas. In the atrophic macula area, irregular hypofluorescence was observed in ICG angiography, which might be caused by filling defect and/or block. Many flecks revealed hyperfluorescence in fluorescein angiography and hypofluorescence in ICG angiography, suggesting that focal circulatory disturbances in the choriocapillaries exist beneath the flecks.

Adolescent↗

PubMed1997

[Aging and the focal macular electroretinogram].

Focal macular electroretinograms (MERGs) were recorded with a fundus monitor through an infrared television fundus camera in 112 eyes of 112 normal subjects (68 males, 44 females), using three stimulus spots 5 degrees, 10 degrees, and 15 degrees in diameter. The amplitude and the implicit time of the a-wave, h-wave, and oscillatory potentials (OPs), and the ratio of amplitude of the b-wave to the a-wave (b/a ratio) at each stimulus spot were compared in terms of aging and sex. The amplitude of all components decreased significantly (p < 0.01-0.05) after the fifth decade, and there was a tendency for OPs to decrease more than the a-wave and b-wave. There was no significant effect of age on the h/a ratio and the implicit time of each component. The ratio of increase of amplitude to the enlargement of stimulus spot showed no significant changes with age. There was no significant difference in each component in terms of amplitude and implicit time with sex. The decrease of amplitude of all components after the fifth decade suggests aging of the macular cones. The tendency toward decreasing OPs also suggests aging of the inner retina in the macular region. The proportional changes of amplitude recorded with three different sizes of stimulus spots indicate that there is no significant effect of aging on the fovea, parafovea, or perifovea.

Adult↗

PubMed1997

[The effect of age on short-wavelength sensitive cone electroretinograms and long-and middle-wavelength sensitive cone electroretinograms].

We studied the effect of age on short-wavelength sensitive cone electroretinogram (S-cone ERG) and long-and middle-wavelength sensitive cone ERG (LM-cone ERG) using a contact lens electrode with a built-in light-emitting diode. We recorded ERGs in 31 pseudophakic subjects to avoid the effect of yellowing in human crystalline lens. The intensities of our stimuli were on the asymptote of the intensity-response curve. We performed linear regression analysis against age on the S-cone ERG b-wave (S-b), and the LM-cone ERG a-, b- and d-waves (LM-a, LM-b, LM-d). We found significant age-dependent reduction in the amplitude of S-b, LM-a, and LM-d, significant prolongation in the peak time of LM-b and LM-d, and significant increase in the b/a ratio of the LM-cone ERG, but no significant age correlation between the peak time of S-b and LM-a and the amplitude of the b-wave. Our results provide evidence that age-related changes in S- and LM-cone systems begin in the twenties in humans. Furthermore, a significant increase of the b/a ratio suggests that off-bipolar cells are more vulnerable to aging than on-bipolar cells.

Adult↗

PubMed1997

[Binocular functions in amblyopia and strabismus].

Regarding the changing trends in the concept, definition, etiological classification, and criteria for diagnosis of amblyopia, we reviewed a total of 4,693 cases of amblyopia seen during the past 37 years. The amblyopia was divided into four types: strabismic, anisometropic, ametropic, and form vision deprivative. There was a definite trend for the incidence to decrease and for the diagnosis to be made during earlier age in recent years. Although favorable recovery of visual acuity is obtained after treatment of amblyopia and strabismus, there are difficulties in obtaining good binocular functions in early-onset amblyopia and strabismus. This feature was evaluated in regard to motion perception asymmetry (MPA) and binocular depth from motion (DFM). Many cases of early-onset amblyopia and strabismus showed no disparity stereopsis, or position stereopsis, in spite of the presence of DFM. The MPA appeared to be closely related to early-onset esotropia regardless of age, while it disappeared and motion perception became symmetric 4 to 5 months after birth in normal infants. The DFM seemed to play an important role in maintaining good motor alignment for several years after surgery. I developed a checkerboard pattern stimulator in 1978. This method proved to be useful in developing binocular functions and motor alignment by applying simultaneous bifoveolar stimulation and anti-suppression. Extensive exposure to the stimulation was essential for therapeutic success.

Adolescent↗

PubMed1997

[Two cases of the retroaortic left renal vein and a morphogenetic consideration of the anomalous vein].

The left renal vein rarely passing behind the abdominal aorta is called "the retroaortic left renal vein". We encountered two cases of the retroaortic left renal vein during the student course of dissection at Iwate Medical University School of Medicine in the years 1986-1997. The incidence of the retroaortic left renal vein was calculated at 2/266 or 0.75%. We observed and recorded the two cases of the retroaortic left renal vein by photographs and line drawings. Then, to consider the morphogenesis of the anomalous vein, we studied 16 cases of the renal collar (the circumaortic renal venous ring) from 149 bodies. Moreover, we observed and recorded the relations between the left renal vein and the lumbar veins in 19 bodies dissected in 1996. Results were compared with those of the reports by some different authors and conclusions were as follows. 1. The incidence of the retroaortic left renal vein is estimated approximately at 0.75%. 2. The retroaortic left renal vein is derived from the renal collar (circumaortic renal venous ring) at an embryonic stage and is completed by the regression and disappearance of the ventral (preaortic) limb and the persistence of the dorsal (postaortic) limb at a later stage. The ventral limb originates from the anastomosis between the subcardinal veins and the dorsal limb originates from the anastomosis between the supracardinal veins (external vertebral venous plexus). The left lumbar veins drain into the inferior vena cava by using the intersupracardinal anastomosis (external vertebral venous plexus). The dorsal limb and the left lumbar veins are considered to use a same venous route passing dorsal to the abdominal aorta. Indeed, in the 16 cases of the renal collar studied, the dorsal limb use the left second lumbar vein in 7 cases, the third lumbar vein in 6 cases, the fourth lumbar vein in 1 case, both the second and the third lumbar veins in 1 case and unknown lumbar vein in 1 case. Moreover, in the two cases of the retroaortic left renal vein the dorsal limb use the third lumbar vein. 3. The retroaortic left renal vein of our cases leaves the renal hilus behind the renal artery (usually in front of the artery) at the level of the intervertebral disc between the second and the third lumbar vertebrae (just one verteral body lower than usual) and flows into the inferior vena cava by using the left third lumbar vein. The reason why ventral (normal) route of the left renal vein disappear may be that the vein leaves the renal hilus at the lower level and the more dorsal position than usual.

Aged↗

PubMed1996

Occult macular dystrophy.

PURPOSE: Occult macular dystrophy is a hereditary macular dystrophy without any visible abnormality of the fundus or abnormality indicated by fluorescein angiography even when visual acuity is decreased. Normal full-field electroretinogram in both cone and rod components with abnormal focal macular cone electroretinogram is the key to diagnosing this disorder. The purpose of this study was to identify the function of the macular rods and to provide detailed clinical findings in occult macular dystrophy. METHODS: Thirteen patients from eight families were examined. The fundi of 12 patients were essentially normal (occult macular dystrophy), and the oldest patient in one family disclosed bull's eye maculopathy. In the 12 patients, including the patient with bull's eye maculopathy, the profiles of cone and rod absolute thresholds were performed across the 60-degree horizontal meridian of the posterior pole. RESULTS: All 12 patients showed cone sensitivity loss only in the macular area. Six relatively young patients revealed normal rod sensitivity, whereas six older patients showed borderline rod sensitivity or abnormal rod sensitivity in the macular area. CONCLUSIONS: The pathology of occult dystrophy involves either only the macular cone system or macular cone and rod systems without any visible abnormality. This difference of the pathology suggests a different clinical entity or a different stage of occult macular dystrophy.

Adolescent↗

PubMed1996

Differences between store-dependent Ca2+ fluxes in lymphocytes from African Americans and whites.

OBJECTIVE: To investigate differences between store-dependent Ca2+ in African American and white men. METHOD: Thapsigargin, a potent and specific inhibitor of the sarco(endo)plasmic reticulum Ca(2+)-ATPase, was used as a probe to elicit store-dependent Ca2+ fluxes. Treatment with this agent caused a rise in the cytosolic free Ca2+ due to the egress of Ca2+ from thapsigargin-sensitive Ca2+ stores and the acceleration of external Ca2+ influx through store-dependent Ca2+ channels. DESIGN: Lymphocytes were obtained from 22 African Americans and 23 whites. These cells were subjected to thapsigargin treatment and changes in the cellular Ca2+ profiles were monitored. RESULTS: Both in Ca(2+)-free and in Ca(2+)-containing media the increases in cytosolic free Ca2+ concentrations after thapsigargin treatment were greater in lymphocytes from African Americans than they were in those from whites. The greater levels of cytosolic Ca2+ concentration were coupled with higher rates of Ca2+ extrusion in thapsigargin-treated lymphocytes from African Americans. CONCLUSIONS: These findings suggest that store-dependent Ca2+ fluxes are greater in lymphocytes from African Americans than they are in those from whites. This phenomenon increases the Ca2+ turnover rate and might augment the sensitivity to agonists acting through Ca2+ signaling systems, thereby predisposing African Americans to essential hypertension.

Adult↗

PubMed1996

[Foveal cone densitometry in high myopia].

We performed foveal cone densitometry using a modified fundus camera in 17 eyes of 17 normal subjects (age range, 20 to 47 yr, refractive error, +2.0 to -2.5 D) and 15 eyes of 15 high myopia subjects with normal visual acuity (age range, 18 to 46 yr, refractive error, -9.0 to -14.5 D). After fully bleaching, the density of photopigment was measured for 7 minutes by a test spot of 562 nm in wavelength and 1 degree in diameter, focussed on the fovea. Two-way density and the time constant of pigment regeneration were calculated. No significant difference was found in two-way density between the two groups. The time constant in high myopia (161.6 +/- 36.6 sec), however, was significantly increased (p < 0.01), compared with normals (124.0 +/- 28.7 sec). To study the correlation of psychophysical visual function, we performed a photostress recovery test, which revealed a significant delay of the recovery time in high myopia (p < 0.01). These results suggest that a delay in foveal cone pigment kinetics precedes loss of cone cells or chorioretinal degeneration in high myopia.

Adolescent↗

PubMed1996

[Normal values of retinal response densities in multifocal electroretinogram].

Multifocal electroretinograms (ERG) were recorded from 21 normal eyes to investigate the spatial distribution and inter-individual variation of local cone responses. To compensate for the effect of refractive lenses, test distances were adjusted to obtain a constant magnification on the retina. Significant nasal-temporal asymmetry was observed near the fovea with higher response densities in the temporal retina along the horizontal meridian. No significant supero-inferior asymmetry was observed along the vertical meridian. The average coefficient variation (standard deviation/average) of retinal response density for all areas was 0.35. In the clinical application of the multifocal ERG these results must be taken into consideration.

Adult↗