Biomedical subjects

K Akazawa

Publications and source records attributed to K Akazawa.

At least 109 records · Page 6Linked to original sources

PubMed1994

Change in the three-dimensional shape of the stomach in the developing human fetus.

To reveal the developmental characteristics of the fetal stomach in utero, this study was made on 879 subjects from 20 to 40 weeks' gestation. By applying the system of 'Modeling a three-dimensional shape from a silhouette by detecting symmetry' which we devised, we reconstructed the three-dimensional shape, from the outline of the longitudinally transected fetal stomach, obtained from the real-time ultrasound image. Age-related changes in gastric volume and sphericality (parameters produced by the above mentioned method) were analyzed using piecewise linear regression. The fetal stomach volume increased linearly from 20 to 37 weeks' gestation and decreased thereafter to 40 weeks' gestation, with a critical point at 37 weeks' gestation. The sphericality of the fetal stomach shape was also seen to decrease linearly from 20 weeks' to the critical point at 27 weeks' gestation, thereafter remaining constant regardless of the advance in gestation to term. These findings indicate that at 20-27 weeks' gestation, the stomach is of a fusiform-like shape. From 27 weeks' gestation onwards, greater and lesser curvatures become apparent, clearly identifying the cardiac and pyloric regions. The decrease in stomach size after 37 weeks' gestation is also in good accord with the decrease in amniotic fluid volume. The analytical method presented here can help to understand the pathogenesis of gastrointestinal lesions in the developing fetus.

Embryonic and Fetal Development↗

PubMed1994

Unique change of pancreastatin-like immunoreactivity in cerebrospinal fluid by aging.

Using a specific antiserum for the C-terminal glycine amide region of human pancreastatin (PST), pancreastatin-like immunoreactivity (PST-LI) was measured in cerebrospinal fluid (CSF) from 447 subjects (368 +/- 10.8 pmol/l, mean +/- S.E.M.) free from endocrine diseases. The CSF contents of PST-LI showed a mountain-shape type change which peaked at 40 years of age. The highest concentration was found in the group of ages 40-49 years old (412 +/- 22.9 pmol/l) and the lowest concentration was found in the group of ages 80-89 years old (293.2 +/- 45.2 pmol/l) among various age groups. Gel chromatographic examination revealed the presence of two major forms (MW 13,500 and 5,400) of PST-LI in CSF. Because of the character of this antibody, the large molecular form is possibly an N-terminally elongated PST and the other may be PST-52. This may be the first report on the unique age-related change of PST concentration in CSF.

Adolescent↗

PubMed1994

Growth pattern and prognosis of gastric cancer invading the subserosa.

Gastric cancer invading the subserosa with infiltrative growth was classified as part of the serosal invasion group and named prognostic serosal invasion positive [ps(+)] histologically. We analyzed clinicopathological features and prognosis of 166 Japanese patients with gastric cancer invading the subserosa, according to the growth pattern. All patients were treated in the Department of Surgery II, Kyushu University. Patients with infiltrative growth (ss gamma) were younger and their tumors were frequently undifferentiated compared to findings in those with noninfiltrative growth: expansive (ss alpha) and intermediate growth (ss beta). There was no difference in any other clinicopathological characteristic between those with infiltrative and noninfiltrative growth tumors. The 10-year survival rate was 66.7% for the infiltrative type and 54.2% for the noninfiltrative type, with no statistically significant difference. Lymph node metastasis, curative resection, and extended lymph node dissection, but not growth pattern, proved to be independent prognostic factors, as determined by multivariate analysis. Our findings suggest that it is not the growth pattern which affects the prognosis of ss cancers. Extensive lymph node dissection should be done when lymph node metastasis is present.

Adult↗

PubMed1994

Postoperative chemotherapy including intraperitoneal and intradermal administration of the streptococcal preparation OK-432 for patients with gastric cancer and peritoneal dissemination: a prospective randomized study.

We studied the effects on survival time of postoperative immuno-chemotherapy, including the streptococcal preparation OK-432, in patients with gastric cancer and synchronous peritoneal dissemination. The patients were prospectively randomized and a valid statistical assessment could be made for 109. Patients randomized to group B received therapy that is widely used in Japan to treat patients with gastric cancer: mitomycin C (MMC) and UFT, a combination of tegafur and uracil in a molar ratio of 1:4, for 1 year. Patients randomized to group A received the same drugs as were given to group B patients plus OK-432 i.p. for 7 days, beginning on postoperative day 0, and OK-432 by intradermal injection for 1 year, at 2-week intervals. There were no differences between the two groups in any known prognostic factor or in the dose of any drug administered except for OK-432. There was no difference in the toxicity rate between the groups. In this negative trial, there was no improvement in survival time with the addition of OK-432 to MMC and UFT for patients with gastric cancer and peritoneal dissemination.

Aged↗

PubMed1994

Microsoft Excel Program for creating attractive survival curves.

This paper describes the design of a Microsoft Excel Program which interactively creates attractive and outstanding survival curves. This program enables medical researchers to easily create quality presentation graphs of survival curves and obtain high quality slides and prints, which can be inserted in papers or used directly at medical meetings. Through the use of vertical bars, this program can display the exact points where censored cases occur on survival curves, making it possible to monitor censoring patterns between groups. Furthermore, this program can also create survival curves based on the proportional hazards model for specific patterns of covariate values, given estimated regression coefficients and baseline survival function. This program may be a most useful and effective tool in creating medical research papers containing survival analysis.

Age Factors↗

PubMed1994

The organization of statistical activities at medical research institutions.

In this paper, we discuss the organizational structure for the conduct of statistical activities at medical Colleges and Universities. Here, we have particularly focused on two significant statistical activities, i.e., statistical consultation and research. The consulting service for medical researchers consists of practical statistical analysis, instruction on computer manipulation and software, response to reviewer's comments and statistical design of prospective studies. From our various experiences, we describe the actual implementation of statistical consultations for medical researchers. It has played an important role in supporting medical research. In addition, we also outline some research, with respect to new ways of applying statistics in medical science. This paper concludes that it may be practical for the existing computer center or department of medical informatics, in charge of the computing service, to conduct statistical activities until formal organizations are established at the academic institution. To realize the conduct of statistical activities by Department of Medical Informatics, it needs a team of biostatisticians, data analysts and computer personnel.

Computer Systems↗

PubMed1994

Outpatient follow-up system using a personal computer for patients with hepatocellular carcinoma after surgery.

A simple outpatient follow-up system was developed with a laptop personal computer to assist management of patients with hepatocellular carcinoma after hepatic resections. Since it is based on a non-relational database program and the graphical user interface of Macintosh operating system, those who are not a specialist of the computer operation can use it. It is helpful to promptly recognize current status and problems of the patients, to diagnose recurrences of the disease and to prevent lost from follow-up cases. A portability of the computer also facilitates utilization of these data everywhere, such as in clinical conferences and laboratories.

Carcinoma, Hepatocellular↗

PubMed1994

A flexible random allocation program for multi-institutional clinical trials.

This paper describes a flexible random allocation program that assigns treatments to patients according to their prognostic factors in multi-institutional clinical trials. The source lists are available in the appendix of this paper. This program is based on Pocock and Simon's minimization method and Zelen's method for institution balancing. The numbers of institutions, treatments, and prognostic factors can be set arbitrarily. The maximum number of institutions, treatments, or prognostic factors that can be accommodated by the program is limited only by the size of the main memory. For example, an IBM-PC with a 640KB main memory can run a program of 1500 institutions, 4 treatments and 20 prognostic factors.

Humans↗

PubMed1994

Estimation of risk of major complications after hepatic resection.

To identify the risk factors predicting major postoperative complications from among preoperative and intraoperative variables, an extensive retrospective analysis of 209 patients who underwent hepatic resections was performed using multivariate logistic regression. The major complications were defined as liver failure, intractable ascites and pleural effusion, intraperitoneal infection, intra-abdominal hemorrhage requiring reoperation, major bile leakage, and gastrointestinal tract bleeding. First, detailed pre- and intraoperative data including medical history, laboratory data, portion and extent of hepatectomy, operative time, and amount of blood loss were univariately analyzed. Next, any significant variables were multivariately analyzed using the logistic regression method. Diabetes, increased intraoperative blood loss, resection of segment 8, and an increased serum blood urea nitrogen level were independent and significant variables predicting major postoperative complications. A higher level of serum cholesterol and a procedure involving a portion of left lateral segment were found to decrease the risk. Both more careful operative procedures and intensive management of DM and renal dysfunction in the perioperative period could result in a better quality of life after hepatic resection.

Blood Loss, Surgical↗

PubMed1994

Computer program for the proportional hazards measurement error model.

The Cox-regression analysis based on the partial likelihood assumes that the covariates, or independent variables, are exactly measured without error. If the covariates are subject to measurement error and the error-prone observed values are used in the analysis by simply ignoring the measurement error, the results are generally biased and misleading; the bias does not diminish as the sample size is increased. The objective of the paper is to briefly describe a method searching for asymptotically unbiased estimates of the parameters correcting for the measurement error in the Cox-regression model and to present a FORTRAN program to perform the correction method; asymptotic standard errors of the corrected estimates are also obtained. The measurement error distribution, that is the conditional distribution of the observed values given the true value, must be specified. An advantage of the method described is that it does not require any assumption on the distribution of the true values; in other words, <--> values are treated as unknown fixed constants. It can accommodate tied failure times unless ties are very frequent, and any censorship or loss to follow-up are allowed as long as they are 'independent of survival'.

Likelihood Functions↗

PubMed1994

The relationship between age-related heart rate changes and developing brain function: a model of anencephalic human fetuses in utero.

We attempted to identify the brain segment which controls heart rate changes in human fetuses with advancing gestation. Twelve anencephalic and 165 normal fetuses (control-group fetuses) between 25-32 weeks' gestation were studied. The instantaneous fetal heart rate (FHR) data were obtained from each fetus for a continuous 90-120 min period, using an external cardiotocograph. Calculations included the 'individual probability distribution matrices' in which the FHRs at 1 beat/min intervals between 110 and 180 beats/min, the beat-to-beat differences (DFHRs) between +/- 5 beats/min and the probability values were arranged in rows, columns and the corresponding elements, respectively. Using 2-gestational-week intervals probability distribution matrices (age-group probability distribution matrices) obtained from 335 normal fetuses in our previous study as a reference, the difference between a given 'individual probability distribution matrix' and the corresponding age-group probability distribution matrix' was quantified as the 'difference rate' according to the formula in the text. From 25-26 to 27-28 weeks' gestation, the 'difference rates' in four anencephalic fetuses, with only the spinal cord preserved, were significantly higher in value than those of control-group fetuses, whereas the rates in four fetuses with both the spinal cord and medulla oblongata preserved, indicated no significant differences. From 29-30 to 31-32 weeks' gestation, the rates of the four fetuses with the spinal cord and medulla oblongata preserved, showed significant differences from the control-group fetuses. These findings suggest that there is a critical period between 27-28 and 29-30 weeks' gestation with regard to the developing brain function pertaining to FHR changes. In the early stage, the medulla oblongata plays a role in FHR changes, whereas, in the latter stage, the brain cephalad to the medulla also appears to take on the role of FHR regulator.

Anencephaly↗

PubMed1994

In vivo assessment of prevention of white-noise-induced seizure in magnesium-deficient rats by N-methyl-D-aspartate receptor blockers.

The behavioral changes associated with seizures induced by auditory stimulation in magnesium (Mg)-deficient rats originate in deep brain structures and secondarily project to neocortex. In the present study, we examined the roles of N-methyl-D-aspartate (NMDA) receptors in this seizure model. The intraperitoneal administration of the competitive NMDA receptor blocker DL-2-amino-7-phosphonoheptanoic acid (36 and 72 mg/kg) and the non-competitive NMDA receptor blocker MK-801 (1.35 and 2.7 mg/kg), completely prevented the induction of seizure and bradyarrhythmia or sudden death resulting from seizure. Therefore, the white-noise-induced seizures in Mg-deficient rats are linked to increased neuronal excitability via the NMDA receptor.

2-Amino-5-phosphonovalerate↗

PubMed1994

Long-term results of subtotal esophagectomy with three-field lymphadenectomy for carcinoma of the thoracic esophagus.

OBJECTIVE: This study evaluated the impact of aggressive surgery on survival in patients with carcinoma of the thoracic esophagus. SUMMARY BACKGROUND DATA: Prognostic value of lymph-node status for patients with esophageal carcinoma was emphasized, although it is currently under debate whether extensive lymph node dissection improves survival. METHODS: Two hundred ninety-five patients with thoracic esophageal carcinoma were admitted to Kagoshima University Hospital from December 1982 to December 1990. Esophagectomy was performed on 244 (82.7%) of these patients; 106 of whom underwent three-field lymphadenectomy (bilateral cervical, mediastinal, and abdominal regions) were analyzed regarding lymph-node status, tumor recurrence, and the effect of prognostic factors on survival using Cox's proportional hazards model. RESULTS: Hospital mortality and morbidity were 10.4% (11/106) and 65.1%, respectively. Seventy-eight patients (73.6%) had nodal involvement, including 49 patients with abdominal lymph-node metastases and 46 patients with recurrent nerve-node metastases. Five-year survival rates were 54.5% for 16 patients with a solitary nodal metastasis, 30.3% for stage III, 17.4% for stage IV, and 7.2% for 28 patients with six or more metastatic nodes. The most frequent sites of recurrence were the upper mediastinal region and the lung--its incidence increased significantly as the number of positive nodes increased. The most unfavorable prognostic factors included regional or recurrent nerve-node metastasis and patient age of more than 71 years. CONCLUSIONS: Three-field lymphadenectomy, including especially the removal of bilateral recurrent nerve nodes in the cervical region, is essential for improving the survival of patients with carcinoma of the upper two thirds of the thoracic esophagus.

Adult↗

PubMed1994

Serum erythropoietin levels in term and preterm infants during the first year of life.

PURPOSE: To evaluate the kinetics of erythropoietin (EPO) production and address the pathogenesis of anemia of prematurity, we measured EPO levels in infants during the first year of life. PATIENTS AND METHODS: Using a radioimmunoassay, serum EPO levels were measured in 97 infants classified into three groups according to weight: group A, n = 40, < 1,500 g; group B, n = 19, 1,500-2,499 g; and group C, n = 38, > or = 2,500 g. RESULTS: The serum EPO level ranged widely during the early neonatal period from days 0 to 6 (group A, < 5 to 307 mU/ml; group B, 10-340 mU/ml; and group C, 9-108 mU/ml). EPO reached its lowest level (< 20 mU/ml) between days 7 and 50 in all groups. The hemoglobin concentration reached its nadir between days 51 and 150 in all groups, with the lowest concentration observed in low birth weight infants. In contrast, the EPO level during the anemic phase was approximately 20 mU/ml and was independent of birth weight. A negative correlation between serum EPO level and hemoglobin concentration was observed only in group C (r = -0.54, p < 0.05). The negative slope of the regression equation in group C exceeded that of groups A and B (p < 0.05). When the relationship between EPO and Hb was evaluated over periods of 7-50 days, 51-100 days, and > 101 days, respectively, we noted a significant correlation between values on days 7 and 50 in group A (r = -0.53, p < 0.05) and between days 51 and 100 in group B (r = -0.76, p < 0.05). CONCLUSIONS: These data suggest the appreciable EPO production in premature infants, but its insufficient response to the depressed hemoglobin level, implying the need to administer exogenous EPO to infants with anemia of prematurity.

Anemia↗

PubMed1994

Risk factors related to liver metastasis in colorectal carcinoma: a multivariate analysis of clinicopathologic and immunohistochemical variables.

Specimens from 48 consecutive patients undergoing surgery for colorectal carcinoma and having synchronous or metachronous liver metastases (Group 1) and those from 52 consecutive patients who had no evidence of hepatic metastases within at least 5 year after colorectal resection (Group 2) were selected and compared using a multiple logistic regression analysis. A multivariate analysis using a stepwise logistic regression revealed six independent risk factors significantly related to hepatic metastases. In addition, the following logistic regression model was obtained from this analysis. P = exp a/(1 + exp a): a = 3.524(SM-V) + 2.731(Ex-V) + 2.718(E/M) + 2.562(Lo) + 1.858(p53) + 1.941(HIR) - 4.397, where P is the probability of hepatic metastasis given six independent risk factors (E/M, Ex/M ratio; Lo, location; HIR, host inflammatory cell reaction). When the estimated probability "P" in the above logistic regression model is more than 0.55 after an examination of surgical specimens, we must consider adjuvant chemotherapy and closely monitor the patient to ensure early detection of hepatic metastases.

Adenocarcinoma↗

PubMed1994

Corrected likelihood for proportional hazards measurement error model and its application.

Consider the case where the exact values of covariates in the proportional hazards model may not be observed but instead, only surrogates for them involving measurement errors are available. The maximum likelihood estimate based on the partial likelihood with the true covariate replaced by the observed surrogate is even asymptotically biased and may cause seriously misleading results in covariance analysis based on the partial likelihood. These facts are illustrated by Monte Carlo simulation. A correction to partial likelihood proposed by the first author is studied to gain insight into its merits and limitations in practical applications. The results indicate that when the "effective magnitude of the measurement error" as defined in this article is small, which is indeed the case for most applications, the method will be useful. Some other correction methods for the measurement error in censored survival models are also reviewed and discussed.

Adult↗

PubMed1994

Evaluation of estrogen treatment in female patients with dementia of the Alzheimer type.

This study was designed to investigate the therapeutic efficacy of estrogen in female patients with dementia of the Alzheimer type (DAT). Fifteen DAT patients with a mean age of (mean +/- SE) 71.9 +/- 2.4 years were treated with 0.625 mg of conjugated equine estrogens orally twice a day for 6 weeks. Of the 15 DAT patients, 4 were diagnosed as mild, 7 as moderate and 4 as severe. The effects of estrogen on DAT patients were evaluated by psychometric assessments, behavior rating scales, regional cerebral blood flow (rCBF) measurement and quantitative EEG analysis. Psychometric assessments consisted of Mini-Mental State Examination (MMSE) and Hasegawa Dementia Scale (HDS). Dementia syndromes were evaluated by the GBS-Scale (GBSS) and Hamilton Depression Rating Scale (HDRS). During estrogen replacement therapy (ERT), the mean MMSE score (mean +/- SE) increased significantly from 11.6 +/- 1.9 to 13.2 +/- 2.0 at 3 weeks (P < 0.01) and 13.8 +/- 2.0 at 6 weeks (P < 0.001). The mean HDS score increased significantly from 8.6 +/- 2.1 to 11.5 +/- 2.3 at 3 weeks (P < 0.001) and 11.6 +/- 2.6 at 6 weeks (P < 0.01). Significant improvements in the mean scores of the GBSS and HDRS were also observed in the estrogen-treated group, but not in the untreated control group with a mean age of 71.2 +/- 2.5 years (n = 15). The rCBF was measured by single photon emission computed tomography (SPECT). ERT increased the mean rCBF significantly in the lower frontal region (P < 0.01) and primary motor area (P < 0.02) of the right hemisphere. The mean absolute power delta band values in both left and right frontal EEG (Fp1 and Fp2) (P < 0.01) and theta, band values in Fp2 (P < 0.05) decreased significantly during ERT. It is inferred that ERT significantly improves cognitive functions, dementia symptoms, regional cerebral blood flow and EEG activity in female patients with DAT.

Administration, Oral↗

PubMed1994

[Analysis of computed X-ray tomography of the brain in incontinence patients with senile dementia. Relationship between circulatory defect of the brain, brain atrophy and urinary incontinence].

To evaluate the condition of incontinence in patients with senile dementia, we performed computed tomography X-rays to the brain and analyzed the relationship among the circulatory defect of the brain, the brain atrophy and the degree of incontinence. There were 92 patients subjected to this study who were hospitalised due to senile dementia; 74 patients had vascular dementia, 10 patients had senile dementia of Alzheimer type, and 8 patients had the mixed type. (age ranged: 54-95 years; mean: 80.3 years). The degree of incontinence in these patients varied as follows: 18 patients with continence, 16 patients with moderate incontinence, 58 patients with total incontinence. The diagnosis of circulatory defect of the brain was based on computed tomography observation of periventricular lucency (P.V.L.), and the degree of brain atrophy was evaluated based on 4 criteria: the Lateral body ratio, the Huckman number, the Evans ratio, and the enlargement of the subarachnoid space. Among the 92 patients, P.V.L. was present in 31 patients, among them 27 patients suffered from incontinence. There was a significant correlation between P.V.L. and incontinence (p < 0.001). As the incontinence progressively worsened (Continence, Moderate incontinence Total incontinence), the lateral body ratio increased to 24.8, 27.8, 28.6, (p < 0.05). The Huckman number also increased to 18.3, 19.3, 21.3, (p < 0.01), and the evans ratio likewise 29.9, 32.3, 33.7 (p < 0.01). The enlargement of the subarachnoid space was also correlated with the severity of incontinence. We conclude that urinary incontinence originating from senile dementia is connected to brain atrophy and is strongly influenced by the circulatory disorders of the brain.

Aged↗