Principal component analysis of three-dimensional face shape: Identifying shape features that change with age.

BACKGROUND: The types of shape feature that constitutes a face have not been comprehensively established, and most previous studies of age-related changes in facial shape have focused on individual characteristics, such as wrinkle, sagging skin, etc. In this study, we quantitatively measured differences in face shape between individuals and investigated how shape features changed with age. METHODS: We analyzed three-dimensionally the faces of 280 Japanese women aged 20-69 years and used principal component analysis to establish the shape features that characterized individual differences. We also evaluated the relationships between each feature and age, clarifying the shape features characteristic of different age groups. RESULTS: Changes in facial shape in middle age were a decreased volume of the upper face and increased volume of the whole cheeks and around the chin. Changes in older people were an increased volume of the lower cheeks and around the chin, sagging skin, and jaw distortion. CONCLUSION: Principal component analysis was effective for identifying facial shape features that represent individual and age-related differences. This method allowed straightforward measurements, such as the increase or decrease in cheeks caused by soft tissue changes or skeletal-based changes to the forehead or jaw, simply by acquiring three-dimensional facial images.

Relationship between the retinacula cutis and sagging facial skin.

BACKGROUND: Sagging skin is one of the most concerning esthetic issues for elderly individuals. Although reduced skin elasticity has been reported as the cause of sagging skin, a loss of skin elasticity alone is insufficient to explain sagging facial skin. This study investigated the mechanisms underlying sagging skin, with a focus on the subcutaneous network of collagenous fibers known as the retinacula cutis (RC). METHODS: To evaluate the structure of the RC noninvasively, tomographic images of the face were obtained using magnetic resonance imaging (MRI). The RC was identified by comparing MRI results with histological specimens of human skin. A descriptive scale was used to evaluate the degree of sagging, and a device equipped with a 6-mm-diameter probe was used to measure the elasticity of deeper skin layers and evaluate the physical properties of the skin. RESULTS: The density of RC in subcutaneous tissue correlated negatively with sagging scores and positively with elasticity. CONCLUSION: These results imply that a sparse RC structure contributes to a reduction in the elasticity of subcutaneous tissue, resulting in a greater degree of sagging facial skin. These findings are expected to contribute to the understanding of the mechanisms underlying sagging skin.

Age-related changes in dermal fiber-like structures in facial cheeks.

BACKGROUND/PURPOSE: Despite recent progress in non-invasive measurement methods, such as in vivo laser confocal microscopy (CLSM), it is difficult to quantitatively measure age-related changes in dermal fibrous structures in the face using these methods and qualitative characteristics. We used characteristics extracted from the analysis of CLSM images to quantitatively investigate the effects of aging on dermal fibrous structures in the face. METHODS: CLSM images of dermal fibrous structures were obtained from 90 Japanese females, ranging in age from 20 to 60 years. The feature values of CLSM images were extracted using image analysis methods, such as short-line segment-matching processing and spatial frequency analysis. The qualitative characteristics of the dermal fibrous structures in the CLSM images were obtained by principal component analysis (PCA) of these feature values. The fibrous structures were scored on the basis of qualitative characteristics and then age-related changes in the scores among the subjects were quantitatively evaluated. RESULTS AND CONCLUSION: The PCA results showed that there were two characteristics in the images of fibrous structures: clearness and directionality. The clearness of fibrous structures decreased and directionality isotropy increased with age.

The relationship between dermal papillary structure and skin surface properties, color, and elasticity.

BACKGROUND/PURPOSE: The skin contains an undulating structure called the dermal papillary structure between the border of the epidermis and dermis. The physiological importance of the dermal papillary structures has been discussed, however, the dermal papillary structures have never been evaluated for their contribution to skin appearance. In this study, we investigated the correlation between the dermal papillary structure and skin color and elasticity. In addition, the relationship was validated with skin model experiments. METHODS: The dermal papillary structures in the skin of the female cheek were quantitatively measured by in vivo confocal laser scanning microscopy images. In addition, the skin color and elasticity were measured at the same site. A skin model with dermal papilla-like structures was created by referring to the optical and shape properties of the skin using agar gel and a scattering sheet. RESULTS: Correlations were found between the dermal papillary structures and skin color irregularity and skin elasticity. These relationships were verified by the experiments employing a skin model. CONCLUSION: The results of this study indicated that the dermal papillary structure is also an important factor for skin appearance such as color and elasticity.

Changes in dermal papilla structures due to aging in the facial cheek region.

BACKGROUND/PURPOSE: In the past, it has been possible to measure the dermal papilla structures which are undulations between the epidermis and dermis by noninvasive method. However, almost all of previous studies were not intended to measure facial skin but another site of body. Here, we investigated age-dependent alterations for dermal papilla structures in the facial cheek region after elucidating the difference of characteristics between the body site. METHODS: The surface of the dermis was observed under scanning electron microscope (SEM) using face and abdominal skin biopsy samples. A total of 90 Japanese women were investigated by in vivo confocal laser microscope (CLSM). The number and the shape in the horizontal cross-sectional images of the dermal papilla were analyzed. RESULTS: The facial skin had different characteristics in comparison to the abdominal skin by SEM observation. Under CLSM observation, we found abnormal dermal papilla structures which were accompanied by spots or enlarged pore areas and eliminated these structures from our analysis. We revealed a decrease in the number of normal dermal papilla structures with age and large individual differences at younger ages. CONCLUSION: We found abnormal dermal papilla structures and differences in the dermal papilla structures between face and other body site. With these taken into consideration, we could precisely investigate the aging alteration of normal dermal papilla structures in the face.

Fundamental study of osteoclast chemotaxis toward chemoattractants expressed in periodontitis.

BACKGROUND AND OBJECTIVE: Periodontitis is a chronic inflammatory disease that leads to bone resorption by osteoclasts (OCs). Several factors contribute to the differentiation of OCs from hematopoietic precursors. Cellular chemotactic factors are expressed in periodontitis tissue, but the effects of these chemoattractants on OCs are not well understood. Here we examined the effects of chemoattractants produced in inflamed periodontal tissue on OC chemotaxis. MATERIAL AND METHODS: Rat bone-marrow OCs were cultured in OC culture medium for 3 or 6 d. Using EZ-TAXIScan™, the chemotactic response of these OCs to several chemoattractants [monocyte chemotactic protein-1; macrophage inflammatory protein 1α; regulated on activation, normal T-cell expressed and secreted; stromal cell-derived factor-1α; and complement activation product 5a (C5a)] was measured. In addition, we measured the effect of C5a-specific inhibitors on chemotactic responses toward C5a. The recorded chemotactic responses were quantitatively analysed using ImageJ software. RESULTS: Chemoattractants associated with periodontal disease significantly increased the chemotactic activity of differentiated rat OCs in a concentration-dependent manner, with C5a inducing the highest chemotactic activity of OCs cultured for 3 or 6 d. The C5a-specific inhibitor significantly inhibited chemotaxis toward C5a in a concentration-dependent manner. CONCLUSION: We suggest that C5a plays an important role in pathologic bone resorption in periodontal disease by stimulating the chemotaxis of OCs. Therefore, C5a is a potential target for the treatment of periodontal disease.

Impact of an ultrasound-guided radiofrequency ablation training program on the outcomes in patients with hepatocellular carcinoma.

PURPOSE: The aim of this study was to retrospectively evaluate the impact of a training program on the safety and efficacy of percutaneous ultrasound-guided radiofrequency ablation (RFA) for the treatment of hepatocellular carcinoma (HCC). MATERIALS AND METHODS: A total of 227 patients with 296 HCC nodules who underwent percutaneous RFA with or without transcatheter arterial chemoembolization at our institution were included. There were 163 men and 64 women with a mean age of 74.2±8.3 (SD) years (range: 41-89 years). Percutaneous ultrasound-guided RFA was performed by three trainees (205 HCC nodules in 157 patients) or a mentor (91 HCC nodules in 70 patients) after preprocedural preparation including planning ultrasonography. We compared background-related, tumor-related, and treatment-related factors, and local recurrence and complication rates between the trainee group and the mentor group. Similarly, we compared these variables among the years 2015, 2016, and 2017 for trainee group. RESULTS: The proportion of easy-to-treat tumors in the trainee group (109/205; 53.2%) was greater than that in the mentor group (33/91; 36.3%) (P=0.020). No significant differences were observed in procedure difficulty among the years 2015, 2016, and 2017 for trainee group (easy-to-treat HCC nodules: 25/47; 53.2% vs. 39/79; 49.4% vs. 45/79; 57.0%. P=0.775). The local recurrence rate in the trainee group was 8.8% (18/205 HCC nodules) which was equivalent to 7.7% in the mentor group (7/91 HCC nodules). No significant differences were observed in local recurrence rate (8.8% vs. 7.7%, respectively; P=0.621) and major complication rate (1.3% vs. 1.4%, respectively; P=0.999) between the trainee group and the mentor group. No significant differences were observed in local recurrence rates ([5/47; 10.6%] vs. [11/79; 13.9%] vs. [2/79; 2.5%]) (P=0.109) and major complication rates ([1/36; 2.8%] vs. [1/62; 1.6%] vs. [0/59; 0%]) (P=0.701) between the years 2015, 2016, and 2017 for trainee group. CONCLUSION: A well supervised training program that includes planning ultrasonography fosters the efficacy and treatment quality of RFA for HCC.

Failure of fixation suppression of caloric nystagmus and ocular motor abnormalities.

Caloric nystagmus is substantially suppressed by visual fixation. The degree of suppression of caloric nystagmus is influenced by the condition of visual fixation. We studied the percent reduction in slow-phase velocity of caloric nystagmus by visual fixation and certain abnormalities in optokinetic nystagmus, smooth pursuit, and maintenance of ocular position of gaze in 38 patients with disorders of the CNS. The inability to suppress caloric nystagmus by visual fixation correlated with reduction in optokinetic nystagmus, deficit in smooth pursuit eye movements, and presence of gaze nystagmus. It seems probable that modulation of the vestibulo-ocular reflex is influenced by the same mechanisms that are concerned with optokinetic nystagmus, maintenance of ocular position of gaze, and smooth pursuit eye movements.

Relationship between urinary cadmium and mortality among inhabitants living in a cadmium polluted area in Japan.

A 15 year follow-up study of 3119 inhabitants living in a cadmium polluted area was conducted to investigate the influence of environmental cadmium exposure on the mortality. The cumulative survival curves of the subjects with urinary cadmium concentration > or = 10 microg/g creatinine was lower than that of the subjects with < 10 microg/g creatinine in the men aged 50-59 and 60-69 years and in the women aged 60-69 and 70-79 years. In the men aged 50-69 years and the all aged women, the cumulative survival curves became lower in proportion to the increase of urinary cadmium concentration, when the subjects were divided into four groups according to the amount of urinary cadmium concentration (< 5, 5-9.9, 10.1-19.9, > or = 20 microg/g creatinine). These results suggested a dose response relationship between cadmium exposure and mortality.

Glycoconjugates in the vestibular organs as revealed by the silver methenamine method.

The glycoconjugates in the vestibular organs of the guinea pig were studied after staining by the silver methenamine method and by the periodic acid-Schiff (PAS) reaction. The organic matrix of otoconia, otolithic membranes and cupulae were stained to the same degree by the PAS reaction. In contrast, the mineralizing and non-mineralizing matrices were clearly distinguished by the silver methenamine method. The otoconia were surrounded by an intensely stained organic matrix, while the otolithic membranes and cupulae were moderately stained. This histochemical difference suggests that the positively stained organic matrix of otoconia is not identical to the otolithic membranes and cupulae in terms of its biochemical composition. The strongly stained material may play an important role in turnover of calcium in otoconia. The contact areas between type I hair cell and nerve calyx were contained silver methenamine-positive material which is probably involved in adhesion of these cell membranes.

Cerebral autoregulation in patients with orthostatic hypotension.

The present study was conducted to determine the relationship between autonomic nervous function and cerebral autoregulation in 17 patients with vertigo or dizziness. Autonomic nervous function was examined by measuring systolic blood pressure response and dynamic electrocardiogram R-peak to R-peak response upon standing up. Regional cerebral autoregulation was examined by comparing cerebral blood flow in both supine and standing positions with single photon emission computed tomography. Moreover, the relationship of each of these three measures to postural provocation of symptoms was studied. The findings indicated that autonomic nervous dysfunction does not influence cerebral autoregulation, but autonomic nervous dysfunction was related to postural provocation of symptoms. This might indicate that impaired autoregulation in the brain stem or the peripheral vestibule, which could not be detected by the single photon emission computed tomography, played a role in inducing vertigo or dizziness in patients with orthostatic hypotension.

Initiation of sinusoidal tracking eye movements in man.

Smooth pursuit eye movement was recorded with a DC amplifier during horizontal sinusoidal target motion at 0.3, 0.6, 0.8, 1.0 and 1.2 Hz and a peak-to-peak amplitude of 20 degrees. Eye movement was digitalized at 100 Hz and 12 bits. From the digitalized eye movements, the maximum position error, the correlation coefficient and regression coefficients between stimulus and eye position were calculated in each half cycle. The A/D conversion and calculation were performed using a 16 bit microcomputer (NEC PC 98). Thirteen healthy volunteers with normal smooth pursuit patterns were examined. The correlation coefficient increased, but the maximum position error and the two regression coefficients decreased as the target moved. However, all four stabilized from about the 3rd half cycle regardless of the target frequency. These findings indicate that the smooth pursuit of a sinusoidally moving target reaches the maintenance at about the 3rd half cycle after initiation of two half cycles from the beginning of the target motion. This might be due to a prediction (or learning) of periodicity.

A clinical study of electrocochleography in Menière's disease.

Electrocochleography (ECochG) of 168 ears with definite Meniere's disease was studied. The results were compared with recordings from 29 normal ears and 444 ears with other types of sensorineural hearing loss. It is shown that the SP/AP ratio is much more useful than SP amplitude for detecting endolymphatic hydrops. There was little difference in the mean values of SP/AP from those proposed by many other investigators; the mean values all being near 0.25. From 0.30 to 0.40 of SP/AP was considered adequate as the upper limit. Following intravenous administration of glycerol, a significant decrease in SP/AP was found in 21 Meniere's ears. However, there was no change of SP/AP after oral administration of glycerol and isosorbide. This difference may be due to the fact that a larger oral than intravenous administration is necessary to affect SP/AP. Although a postoperative decrease of 10% or more in SP/AP was observed in 5 patients, 10 patients followed up for 2 years or more after surgery did not show a statistically significant change of SP/AP and pure tone threshold. ECochG should be repeatedly recorded to be useful as a monitor for the presence of hydrops. It is discussed whether biochemical or mechanical changes in endolymph may cause a decrease in SP/AP after the use of dehydrating agents and endolymphatic sac surgery.

Prediction in smooth pursuit.

A quantitative analysis of prediction in smooth pursuit was made in 23 normal subjects. The target wave (random sinusoidal wave), which contains a predictive portion and a nonpredictive portion, was developed by the authors, using a microcomputer. Five parameters were established quantitatively after microcomputer A/D conversion of the eye movements every 10 ms. There was no significant difference in amplitude gain, retinal error velocity, velocity gain or acceleration gain between the predictive and the non-predictive portions. However, a significant difference between the predictive portion and the nonpredictive portion was found in phase lag. We therefore concluded that the predictive function in smooth pursuit, in normal subjects, is the most important factor in the phase relationship between target wave and eye movements.

Optokinetic test comprising both acceleration and constant velocity stimulation (ACV-OKN test).

Normal subjects were exposed to two kinds of optokinetic stimulation, viz. at speeds of 60 degrees/s and 90 degrees/s preceded by acceleration at 6 degrees/s2 and 4.5 degrees/s2, respectively. In most subjects the speed of the eye in the slow nystagmus phase equalled the speed of the rotating device during the acceleration at velocities up to about 60 degrees/s. The eye then lagged behind the speed of the optokinetic stimulus. The upper limit for linear increase in the eye speed of the slow nystagmus phase has been named the "optokinetic fatigue threshold". A new clinical test permitting quantitative assessment of the optokinetic response has been introduced. The maximum eye speed in the slow nystagmus phase has been found to be the most appropriate parameter. Presentation of the results in the form of special charts, named optokinograms, is recommended. Optokinetic disturbances of varying kinds were noted mostly in patients with CNS disorders, but also in patients with diseases of the inner ear.

Involvement of the VIIIth cranial nerve and the brainstem in patients with hemifacial spasm.

Twenty-seven patients with hemifacial spasm underwent neurotological (auditory and equilibrium) examinations to evaluate the VIIIth cranial nerve and/or brainstem involvement. Radiological examinations were performed to evaluate the underlying abnormalities. Twenty patients had abnormal neurotological findings, with the VIIIth cranial nerve involvement being suggested in 10 and brainstem involvement in the other 10. Radiological examinations indicated that vascular abnormalities could be detected more often in the patients with brainstem involvement than in those with VIIIth cranial nerve involvement.

Quantitative comparison between saccadic and ataxic pursuits.

Smooth pursuit has been determined by the examiners' visualization as 'smooth pursuit', 'saccadic pursuit', or 'ataxic pursuit' according to the shapes of the eye movements on the ENG (electronystagmography) recording paper. Even since the introduction of computers for the measurement of smooth pursuit, however, no trial to compare quantitatively between smooth pursuit, saccadic pursuit and ataxic pursuit had been made up to the present. In the present work we analysed 10 smooth (normal) pursuits, 23 saccadic pursuits and 7 ataxic pursuits quantitatively with a microcomputer and found that the phase relationship between target movements and eye movements was the most prominent factor for distinguishing smooth pursuit pattern differences.

Loss of visual suppression of caloric nystagmus in cats.

Loss of visual suppression (VS) of caloric nystagmus was produced after creating flocculus lesions. The flocculus receives visual signals through a climbing fiber pathway via the inferior olive (IO) and through a mossy fiber pathway (MF) presumably via the superior colliculus (SC). In order to elucidate the prefloccular nuclei responsible for VS of caloric nystagmus, VS of caloric nystagmus was investigated after making lesions in such nuclei as the SC and the IO in 42 cats. After the IO lesion, VS of caloric nystagmus was revealed in all IO-lesioned cats throughout the whole experimental course. After the SC lesion, loss of VS was constantly observed and persisted in 7 out of 9 cats. Hence, the MF pathway via the SC is believed to be the most likely candidate for the immediate modification of the vestibuloocular reflex by visual stimuli.

Visual suppression of caloric nystagmus in normal individuals.

The effects of opening of the eyes and of ocular fixation upon caloric nystagmus were investigated during the period of maximum intensity of caloric nystagmus in a series of 32 normal individuals. The percentage reduction in slow-phase velocity induced depended upon the test conditions, but, on the other hand, did not depend upon the temperature of the water applied as caloric stimulus. This latter fact favors the theory of visual suppression of the caloric test. Another striking finding was that a clear correlation definitely existed between the percentage reduction of suppression in slow-phase velocity and that in the multiplication product of amplitude by nystagmus frequency (P.A.F.) during the period of eye opening and ocular fixation. The percentage of suppression in slow-phase velocity is interchangeable with that in P.A.F., which broadens the practical scope of the routine test.