Change in Geographic Accessibility to Dental Clinics Affects Access to Care

Access to dental clinics is a feature of the neighborhood service environment that may influence oral health care utilization. However, residential selection poses a challenge to causal inference. By studying the involuntary relocation of survivors of the 2011 Great East Japan Earthquake and Tsunami (GEJE), we examined the association between changes in geographic distance to dental clinics and dental visits. Longitudinal data from a cohort of older residents in Iwanuma City directly impacted by the GEJE were analyzed in this study. The baseline survey was conducted in 2010, 7 mo before the occurrence of GEJE, and a follow-up was conducted in 2016. Using Poisson regression models, we estimated the incidence rate ratios (IRR) and 95% confidence intervals (CIs) for the uptake of denture use (as a proxy for dental visits) according to changes in distance from the nearest dental clinic to their house. Age at baseline, housing damage by the disaster, deteriorating economic conditions, and worsened physical activity were used as confounders. Among the 1,098 participants who had not worn dentures before the GEJE, 495 were men (45.1%), with a mean ± SD age at baseline of 74.0 ± 6.9 y. During the 6-year follow-up, 372 (33.9%) participants initiated denture use. Compared to those who experienced a large increase in distance to dental clinics (>370.0-6,299.1 m), a large decrease in distance to dental clinics (>429.0-5,382.6 m) was associated with a marginally significantly higher initiation of denture use among disaster survivors (IRR = 1.28; 95% CI, 0.99-1.66). The experience of major housing damage was independently associated with higher initiation of denture use (IRR = 1.77; 95% CI, 1.47-2.14). Improved geographic access to dental clinics may increase dental visits of disaster survivors. Further studies in non-disaster-affected areas are needed to generalize these findings.

Post-Disaster Mental Health and Dietary Patterns among Older Survivors of an Earthquake and Tsunami

OBJECTIVES

Research suggests that cardiometabolic disease risks are elevated among survivors of natural disasters, possibly mediated by changes in diet. Using the Brief Dietary History Questionnaire, we examined (1) dietary patterns among older survivors of the 2011 Great East Japan Earthquake and Tsunami, and (2) the contribution of posttraumatic stress symptoms (PTSS)/depressive symptoms, as well as relocation to temporary housing on dietary patterns and (3) gender differences in the associations.

DESIGN, SETTING AND PARTICIPANTS

Data came from a prospective cohort study of 1,375 survivors aged 65-89 years (44.6% male).

MEASUREMENTS

PTSS/depression onset was evaluated in 2013, 2.5 years after the disaster. Dietary data was collected with a self-administered brief-type diet history questionnaire in 2020. A principal component analysis identified three posterior dietary patterns.

RESULTS

Diet 1 consisted of high intake of vegetables, soy products, and fruits; Diet 2 consisted of carbohydrate-rich foods and snacks/sweets; Diet 3 consisted of high intake of alcoholic beverages, meat, and seafood. Least-squares linear regression revealed that individuals with PTSS/depression were less likely to exhibit Diet 1, while individuals with PTSS were more likely to exhibit Diet 2 and 3. Especially, males who had depression showed an unhealthy dietary pattern. Those who have lived in a trailer-style temporary housing reported less consumption of Diet 3.

CONCLUSION

Survivors of disaster with symptoms of mental illness tended to exhibit less healthy dietary patterns after 9 years. Diet varied by type of post-disaster mental illness, gender, and current social circumstances. We lacked pre-disaster BDHQ data, which is a limitation.

0004 TS-142: A Novel and Potent Dual Orexin Receptor Antagonist with Sleep-Promoting Effects in Rats

Introduction

The orexin system plays a pivotal role in regulating sleep and wakefulness, thus, orexin receptors (OX1 and OX2 receptors) have gained much attention as promising therapeutic targets for the treatment of insomnia. We synthesized a novel and potent dual orexin receptor antagonist (DORA), ORN0829 (investigation code name as TS-142), which was designed to have short-acting effects. Here we report pharmacological and pharmacokinetic profiles of ORN0829 in rats.

Methods

The antagonistic activities of ORN0829 were assessed using calcium mobilization assays. Ala-orexin A-induced [Ca2+]i response was measured with CHO-K1 cells stably expressing human/rat orexin receptor. Rats implanted the EEG/EMG electrodes were orally administrated ORN0829 at doses of 1, 3 or 10 mg/kg at the dark onset and sleep-wake stages were inspected visually. In addition, pharmacokinetic profiles of ORN0829 were investigated in rats.

Results

ORN0829 inhibited Ala-orexin A-increased [Ca2+]i response with a Kb of 0.67/0.44 nmol/L (for human/rat OX1 receptor), and with a Kb of 0.84/0.80 nmol/L (for human/rat OX2 receptor), respectively, indicating that ORN0829 is a potent DORA with no species differences. ORN0829 dose-dependently increased total sleep time and reduced sleep onset latency at doses of 1, 3 and 10 mg/kg. Importantly, the ORN0829 levels in plasma and cerebrospinal fluid rapidly reached a maximum concentration, and decreased with an elimination half-life of less than 1 h.

Conclusion

The present study indicates that ORN0829 is a novel and potent DORA with sleep-promoting effects, and that it exhibits ideal pharmacokinetic profiles (rapid absorption and short half-life) in rats. A phase 2a study of TS-142 using patients with insomnia has been completed, which is presented in a separate poster.

Support

Taisho Pharmaceutical. Co., Ltd.

Subacute Sensory Ataxic Neuronopathy With Thymoma Presenting Marked Improvement After Steroid Therapy

Subacute sensory ataxic neuronopathy is a well-known form of paraneoplastic syndrome. Most sensory neuronopathies are associated with small cell lung cancer and anti-Hu antibodies, and usually show only slight improvement with immunotherapy. To date, there have been few reports of neuropathy associated with thymoma and no treatment strategy has been established for thymoma-related neuropathy. Here, we provide the first report of a case of sensory ataxic neuronopathy with thymoma that showed marked improvement after steroid therapy, even though preceding intravenous immunoglobulin treatments and tumor resection were less effective. A 57-year-old Japanese man was referred to our hospital with a 6-week history of distal paresthesia in his four limbs and an unsteady gait. He presented with left-dominant ataxia in his four limbs due to reduced sensation in his extremities. He also complained of constipation, difficulty urinating, and erectile dysfunction. Upon investigation, including electrodiagnostic studies, the patient was diagnosed as having sensory ataxic neuronopathy with invasive thymoma. A first round of intravenous immunoglobulin therapy, a following thymectomy, and a second round of intravenous immunoglobulin therapy after the surgery were not effective in treating his neurological symptoms. Subsequently, oral steroid therapy was started, which brought about a remarkable improvement; 6 weeks after the beginning of the steroid therapy, his neurological symptoms were resolved, except for slight distal paresthesia in his feet. Although rarely reported, thymoma can underlie sensory neuronopathy, and the response of thymoma-associated sensory neuronopathy to immunotherapy might be better than that of anti-Hu antibody-related neuropathies. Even if the first immunotherapy is not effective in treating neuropathy with thymoma, further immunomodulatory treatment should be tried after treating the tumor.

Residential relocation and obesity after a natural disaster: A natural experiment from the 2011 Japan Earthquake and Tsunami

Natural disasters are often associated with forced residential relocation, thereby affected people experience a change of food environment that results in the increased body mass index. However, there are a few studies that examined whether a change in food environment caused risk of obesity after a natural disaster. To address this question, we leveraged a natural experiment of residential relocation in the aftermath of the 2011 Japan Earthquake and Tsunami. Our baseline data came from a nationwide cohort study of older community-dwelling adults conducted 7 months prior to the disaster. By chance, one of the field sites (Iwanuma City, Miyagi Prefecture) was directly in the line of the tsunami. Approximately 2.5 years after the disaster, we ascertained the residential addresses and health status of 3,594 survivors aged 65 years or older (82.1% follow-up rate). Fixed effects multinomial logistic regression showed that shortened distances to food outlets/bars increased the risks of transitioning from BMI in the normal range (18.5–22.9) to obesity (≥25.0) (Odds ratios: 1.46 for supermarkets; 1.43 for bars; 1.44 times for fast food outlets). Radically changed food access after a natural disaster may raise the risk of obesity among older survivors.

Association of survival and hyperthermia after rt-PA for ischemic stroke

BACKGROUND

Hyperthermia in patients with acute ischemic stroke is associated with poor outcome. Although previous studies have shown a negative effect on functional outcome, even in patients treated with intravenous recombinant tissue plasminogen activator (rt-PA), the effect on survival remains unclear.

AIMS OF THE STUDY

The aim of this study was to evaluate the association between the functional and survival prognosis and hyperthermia in patients with acute ischemic stroke treated with rt-PA.

METHODS

We studied 120 patients treated with rt-PA from 2306 consecutive Japanese patients with acute cerebral infarction at Aomori Prefectural Central Hospital between December 2009 and March 2017. We defined hyperthermia as ≥38°C within 72 hours after rt-PA administration. Propensity score matching was used to compare 34 non-hyperthermia and hyperthermia patient pairs.

RESULTS

Final modified Rankin Scale scores were higher in the hyperthermia group than in the non-hyperthermia group. In addition, the Kaplan-Meier model showed that the non-hyperthermia group had significantly better survival rates than the hyperthermia group (hazard ratio, 5.3; 95% confidence intervals, 1.2-24.8).

CONCLUSIONS

Hyperthermia within 3 days after rt-PA is associated with poor functional prognosis and survival outcome in patients with acute cerebral infarction.

Myelin Oligodendrocyte Glycoprotein-IgG-positive Recurrent Bilateral Optic Papillitis with Serous Retinal Detachment

Autoantibodies against myelin oligodendrocyte glycoprotein (MOG-IgG) have been detected in inflammatory demyelinating central nervous system diseases. A 30-year-old woman had blurred vision, marked optic nerve disc swelling, serous retinal detachment at the macular on optic coherence tomography, and MOG-IgG seropositivity. The patient was thought to have optic papillitis associated with MOG-IgG. Her symptoms rapidly improved after high-dose methylprednisolone therapy. We hypothesize that serous retinal detachment was secondary, arising from optic papillitis. This is the first report of the concurrence of optic papillitis with MOG-IgG and serous retinal detachment. MOG-IgG should be tested in patients with marked optic disc swelling.

Role of endogenous PACAP in catecholamine secretion from the rat adrenal gland

We elucidated the contribution of endogenous pituitary adenylate cyclase-activating polypeptide (PACAP) to neurally evoked catecholamine secretion from the isolated perfused rat adrenal gland. Infusion of PACAP (100 nM) increased adrenal epinephrine and norepinephrine output. The PACAP-induced catecholamine output responses were inhibited by the PACAP type I receptor antagonist PACAP- (6-38) (30-3,000 nM) but were resistant to the PACAP type II receptor antagonist [Lys1,Pro2,5,Ara3,4,Tyr6]-vasoactive intestinal peptide (LPAT-VIP; 30-3,000 nM). Transmural electrical stimulation (ES; 1-10 Hz) or infusion of ACh (6-200 nM) increased adrenal epinephrine and norepinephrine output. PACAP-(6-38) (3,000 nM), but not LPAT-VIP, also inhibited the ES-induced catecholamine output responses. However, PACAP-(6-38) did not affect the ACh-induced catecholamine output responses. PACAP at low concentrations (0.3-3 nM), which had no influence on catecholamine output, enhanced the ACh-induced catecholamine output responses, but not the ES-induced catecholamine output responses. These results suggest that PACAP is released from the nerve endings to facilitate the neurally evoked catecholamine secretion through PACAP type I receptors in the rat adrenal gland.

Role of calcium channels and adenylate cyclase in the PACAP-induced adrenal catecholamine secretion

We elucidated the functional contribution of voltage-dependent calcium channels (VDCCs) and adenylate cyclase to epinephrine (Epi) and norepinephrine (NE) secretion induced by pituitary adenylate cyclase-activating polypeptide (PACAP) in the isolated perfused rat adrenal gland. PACAP increased Epi and NE output, which was inhibited by perfusion with calcium-free solution or by nifedipine, an L-type VDCC blocker. However, the PACAP-induced responses were resistant to omega-conotoxin GVIA, an N-type VDCC blocker, or omega-conotoxin MVIIC, a P/Q-type VDCC blocker. MDL-12330A, an adenylate cyclase inhibitor, inhibited the PACAP-induced increase in Epi, but not NE, output. Treatment with nifedipine and MDL-12330A caused additive inhibition of the PACAP-induced catecholamine responses. These results suggest that opening of L-type VDCCs is responsible for adrenal catecholamine secretion induced by PACAP and that activation of adenylate cyclase is involved in the PACAP-induced Epi, but not NE, secretion. These pathways may act independently of each other.

Interaction of SK(Ca) channels and L-type Ca(2+) channels in catecholamine secretion in the rat adrenal gland

We elucidated the interaction of small-conductance Ca(2+)-activated K(+) (SK(Ca)) channels and L-type Ca(2+) channels in muscarinic receptor-mediated control of catecholamine secretion in the isolated perfused rat adrenal gland. The muscarinic agonist methacholine (10-300 microM) produced concentration-dependent increases in adrenal output of epinephrine and norepinephrine. The SK(Ca) channel blocker apamin (1 microM) enhanced the methacholine-induced catecholamine responses. The facilitatory effect of apamin on the methacholine-induced catecholamine responses was not observed during treatment with the L-type Ca(2+) channel blocker nifedipine (3 microM) or Ca(2+)-free solution. Nifedipine did not affect the methacholine-induced catecholamine responses, but it inhibited the responses during treatment with apamin. The L-type Ca(2+) channel activator Bay k 8644 (1 microM) enhanced the methacholine-induced catecholamine responses, whereas the enhancement of the methacholine-induced epinephrine and norepinephrine responses were prevented and attenuated by apamin, respectively. These results suggest that SK(Ca) channels are activated by muscarinic receptor stimulation, which inhibits the opening of L-type Ca(2+) channels and thereby attenuates adrenal catecholamine secretion.

Evaluation of hemolysis in a pulsatile assist device for centrifugal pump

To evaluate the blood trauma caused by a new device for producing a pulsatile flow of the centrifugal pump, the pulsatile assist device for the centrifugal pump (PAD-CP) that we have developed, a hemolysis study was performed in vitro and in animal experimentation. For the in vitro testing, 2 identical sets of hemolysis test circuits were prepared with 2,400 ml of bovine blood. The 2 circuits were pumped simultaneously. Plasma total hemoglobin levels were less than 40 mg/dl after 3 h, under a pump flow of 2 L/min. Hemolysis increased to a severe level after 4 h of 4 L/min pump flow. The cause of this hemolysis was thought to be a vibration of the circuit because of incomplete compression of the polyurethane tube in the PAD-CP. Five adult sheep (average body weight, 47 kg) were used for in vivo evaluation of hemolysis. Hemolysis was less than 30 mg/dl of plasma hemoglobin after 4 h of open chest extracorporeal circulation with 3.0-3.6 L/min of flow rate using the PAD-CP. Other hematologic changes after PAD-CP driving were within normal limits. We conclude that the PAD-CP has proven to have possible clinical applications.

In vitro evaluation of a pulsatile assist device for a centrifugal pump using a new principle

To induce a pulsatile flow in a centrifugal pump, we developed a new device (pulsatile assist device for centrifugal pump: PADCP) using a new concept. This device consists of a flexible polyurethane tube with an air chamber which is connected to the arterial side of the centrifugal pump circuit directly. A mock circulation system was used for evaluation of this PADCP. Thirty to 40 mm Hg of pulse pressure was obtained under 3-6 L/min of flow rate. By increasing the driving pressure of the PADCP from 200 to 600 mm Hg in a mock system, 4-48 mm Hg of pulse pressure was gained accompanied by a decrease in pump flow and increased left atrial pressure. The decreased pump flow and increased left atrial pressure were recovered easily by increasing the flow rate of the centrifugal pump. Pressures at the proximal site of the PADCP were less than 500 mm Hg. The PADCP was useful to induce a pulsatile flow in a centrifugal pump.

Kinetic Analysis: Benzo(a) pyrene in Southeastern Ohio

Kinetic Analysis has been successful for metallic elements in relatively isolated areas. In this study it is applied to a complex organic compound in a geographical area with a large urban component. Ten media compartments are included, with man as the ultimate receptor. Field data were collected for only 6 of the media and were not used in the analysis but were compared to the calculated steady state concentrations. The greatest differences between calculated and observed values were 4.8-fold for soil and 5.4-fold for sediment. The field sampling regime for soils was biased towards areas of industrialization and probably explains the higher observed value. The lower observed value for sediment is likely due to unknown variables necessary for the estimation of the compartment size and/or the associated transfer rate constants. This study indicated that the Kinetic Analysis technique can be applied successfully to the pre-sampling estimation of the distribution of organic pollutants in environmental systems.

Chemical form of cadmium (and other heavy metals) in rice and wheat plants

Chemical forms of heavy metals such as Cd, Cu, Ni, and Pb in rice and wheat plants grown in nutrient solution containing a heavy metal were investigated. Fractionation of an extract of Cd-treated rice plants on Sephadex G-75 showed cadmium to be associated with organic compounds of high (fraction A), intermediary (fraction B), and low molecular weight (fraction C). Material A, whose molecular weight was greater than 440,000, is probably nonspecific binding of Cd to normal cell components. Materials B and C can be classified as types of metallothionein. The molecular weight of B was 33,100. This material contains 12 mg Cd/g protein. The UV-absorption spectrum of B showed absorptions at 280 and 250 nm. Material B was not eluted even at a very high ionic strength from the DEAE-cellulose column, but it was eluted at a very low ionic strength from a CM-cellulose column, indicating a highly anionic molecule which differs from metallothionein in animals. Fraction C contains two materials: one a Cd-containing material whose molecular weight was estimated to be approximately 7000 and the other an inorganic Cd salt. In addition to cadmium, copper, lead, and nickel in rice and wheat have been studied. As a result, heavy metal-containing materials whose molecular weights were estimated to be approximately 16,000 and 8900 (Ni-treated rice plants), 7000 (Pb-treated rice plants), 5000 (Cd-treated wheat plants), and 21,000 (Cu-treated wheat plants) were isolated.

[Transthoracic catheterization under monitoring by ultrasono-cardiotomography and its clinical usefulness]

When serious postoperative complications such as mechanical malfunction of the implanted valve occur in patients with multiple valvular replacements, it is very urgent to evaluate the function of the valve and heart and to establish an accurate diagnosis as to the damaged prosthetic valve, while giving intensive life-saving bed-side care. Under such circumstances, transvascular heart catheterization necessary for obtaining hemodynamic data or for angiocardiography can not be applied because it is almost impossible for a catheter to pass through a prosthetic valve without potential danger. Then, the present authors have introduced a method of cardiac catheterization by a direct transthoracic route during which cardiac structures are monitored by ultrasono-cardiotomography. This method is called "transthoracic catheterization monitored by ultrasono-cardiotomography," and was applied to cases of double (aortic and mitral) valve replacements. The immobile adhesive area in the vicinity the right ventricular wall is detected from the longitudinal or horizontal cross-section pictures, through which a polyethylene catheter with stylet was introduced from the subxiphoid region and was advanced toward the left ventricle. After introduction of the catheter into the right ventricle, the catheter tip was advanced to the midportion of the ventricular septum, which was selected to avoid the penetration of the tricuspid valve and coronary arteries. Then, the catheter was passed into the left ventricle on the ultrasonic scanning plane along the direction of the short axis of the heart. After placing the catheter into the left ventricle, a small amount of contrast material was injected to confirm the precise positioning of the catheter tip in the left ventricle. Thus, the hemodynamic measurement and angiocardiograpy were performed easily. By utilizing contrast cardiotomography, valvular function was evaluated easily without any side effects as in case of angiocardiography. Furthermore, ultrasono-cardiotomography was sensitive in detecting cardiac tamponade if appeared during direct heart catheterization, making immediate treatment possible. Thus, transthoracic catheterization monitored by ultrasono-cardiotomography was useful for the evaluation of the function of the prosthetic valve, especially in cases with double valve prostheses.

Detection of left ventricular asynergy in myocardial infarction by means of ultrasono-cardiotomography and M-mode echocardiography

The movements of the left ventricular wall in cases of myocardial infarction were studied by ultrasono-cardiotomography and M-mode echo-cardiography. Ultrasono-cardiotomographic and echocardiographic data were collected from 15 consecutive patients with transmural myocardial infarction ranging in age from 28 to 60 years (4 with antero-septal infarction, 5 with postero-inferior infarction, and 6 with infarction of other areas) and also from healthy control subjects. In myocardial infarction, a delay in timing and a decrement in amplitude of the excursion of the infarcted area were observed. As the result, compensatory movement occurred in the non-infarcted area. This compensatory movement was a major contributing factor for the maintenance of the function of the left ventricle. In antero-septal infarction, the pump function was compensated for by the movement of the left ventricular posterior wall (LVPW) and by that of the non-infarcted area of the interventricular septum (IVS). On the other hand, in postero-inferior infarction, the pump function was mainly compensated for by an increment in movement of IVS. This compensatory movement, which was very strong in the acute stage of myocardial infarction, decreased with time after infarction. On the other hand, in the hypokinetic infarcted area, there was a gradual increment of the amplitude of excursion with time after infarction. These findings reflected the degree of the development of collateral circulation. It was found that the degree of asynergy could be determined by the evaluation of the delay in timing and amplitude of the excursion, and of mVCF at basal, middle, and apical portions of the left ventricle.

Ultrasono-cardiotomographic evaluation of histological changes in myocardial infarction

The echo patterns on ultrasono-cardiotomogram were evaluated in relation to the histological changes of the myocardium. The ultrasono-cardiotomographic data were collected from 9 consecutive patients with transmural infarction (3 patients with antero-septal, 5 with postero-in-ferior, 1 with antero-lateral infarction) and also from 11 dogs with experimental myocardial infarction. Analyses of data obtained led to the following conclusion. 1) A decrement of the thickness and deformity of the wall echo: They were detected by a series of azimuthal angle and level ultrasono-cardiotomograms which were obtained by changing the direction and level of the ultrasonic beam through the heart along the long axis of the left ventricle. 2) An increment of echo-intensity of infarcted area: The intensity of abnormal echo of the infarcted area, when evaluated by using the intensity of the echo of normal pericardium as a reference of OdB, was + 10 to +15bB more intense than that of the normal myocardium. 3) The study of the echo patterns in comparison with the histology of myocardium indicated that the echoes related to scar could be classified into 4 types: i) cord-like echo, ii) scattered large nodular echoes, iii) narrow band-like echo, and iv) scattered small nodular echoes. Types i), ii), and iii) indicated the formation of a transmural scar. Thus a possibility was suggested that histological characteristics of myocardial tissue could be estimated by a non-invasive method.

[On deffect of cobalt-chromium-nickel alloy for dental castings (author's transl)]

We studied about castability and microporosity of cobalt-chromium-nickel alloy for dental casting in various methods of fusion and casting. The combinations of fusion and casting were induction fusion and centrifugal casting, arc discharge fusion and argon gas pressure casting and oxy-acetylene flame fusion and centrifugal casting. The following results were obtained. 1. The amount of microposity was smaller, when only mold temperature was low, and as mold temperature and casting temperature were high, castability was better. 2. The arc discharge fusion and argon gas pressure casting was the best method about castability and microporosity in three methods. Second method was the induction fusion and centrifugal casting. 3. In the induction fusion and centrifugal casting, blowing arong gas of 1 l/min to molten metal to protect the metal from oxidization improved the castability the best, but amount of microporosity was large, so that it was needed to lower the mold temperature in this condition. 4. The oxyacetylene flame fusion and centrifugal casting was not suitable for the casting of Co-Cr alloy "Regalloy No. 3", for the alloy was made for the induction fusion casting.

[Studies on the contract of the casting. (II) Influence of core inside the cast (author's transl)]

A alloy has its constant coefficient of casting shrinkage, but its value is changed by casting conditions. This time, we studied with effect of core which exist inside the cast. The results obtained were as follows: 1. The more the strength of core material increases, the smaller the coefficient of casting shrinkage becomes. 2. The smaller the thermal expansion coefficient of core material in solid state, the smaller the casting shrinkage. 3. In case of Silver-Palladium-Gold casting alloy, its actual casting shrinkage (y) has a multiple correlation with the compressive strength (x1) of core material in high temperature, and with the difference (x2) of the original casting shrinkage of the alloy from the casting shrinkage of core material, that is, y = -0.0023x1 + 0.0087x2 + 1.4927 4. Silver-Indium casting alloy is hard to be influenced by the quality of core material, for the alloy has a small shrinkage force.

[Studies on the contract of the casting. (I). Influence of casting condition (author's transl)]

A study was made of the contraction of the Silver-Indium alloy due to the difference of the casting condition, by mean of the quartz pipe, whose thermal-expansion coefficient was very small. The results were as follows. 1) The higher the mold temperature, the smaller the casting shrinkage. 2) When the casting pressure was extremely low the casting shrinkage was great. But if the casting pressure was over 0.16 kg/cm2, the casting shrinkage didn't change. 3) The bigger the sprue size, the smaller the casting shrinkage. 4) The casting temperature of the alloy, the cooling system, the amount of the metal and the form of the wax pattern showed that the casting shrinkage remain the same.