Biomedical subjects
Publications and source records attributed to Y Kominato.
Sequences homologous to the human histo-blood group ABO genes are present in the genomic DNA of various mammals. We have PCR-amplified, subcloned, and sequenced a portion of these genes from several species of primates and found high conservation of the nucleotide as well as the deduced amino acid sequences during evolution.
We conducted in-depth case studies of traffic accidents involving 118 pedestrians, who were struck by the fronts of bonnet-type cars. The data were reviewed in order to correlate injury severity with pedestrian age, and area of body contact, contact surface of vehicle or the local environment, and impact speed. It was found that head injuries caused by impacts against the top surface of car bonnets and leg injuries caused by front bumpers both showed high incidence rates. Both head and leg injuries caused by striking the vehicle were more severe than those caused by striking the road surface. In cases of impact between the head and the solid portion of the vehicle, such as the A-pillar, or in cases of secondary impact between the head and underhood solid structures such as shock tower, injuries tended to be more severe. The location of head impact varied according to the stature of the pedestrians.
Medical examiner's system has been authorized by the act of Autopsy and preservation of corpses and the government ordinance for medical examiner's system since 1949 in Japan, and introduced only in five large cities (Tokyo metropolis, Osaka, Kobe, Yokohama, Nagoya). Recently in Ibaraki Prefecture, new forensic medical service system (Tsukuba Medical Examiner's office) was instituted. This new system is not authorized by the government ordinance, but authorized by the regional ordinance of Ibaraki prefectural governor, therefore this system is enforce only in Ibaraki prefecture. In our new system, medical examiner does not have discretionary power to order an autopsy, and family have a right to reject it, therefore an autopsy rate is very low (about 2%). One hundred and forty four autopsies have been conducted under this system. Ninety four of 144 autopsy cases (67%) were dead from sickness or natural death, in remaining 50 cases manner of death was accidental, suicidal or undetermined. The medical examiner does not conduct autopsies for criminal investigation or homicide cases in Ibaraki prefecture. These autopsies are conducted at the department of legal medicine, University of Tsukuba.
Blood group substance was investigated in serum, cyst fluid and ascites of a patient with mucinous cystadenoma of the ovary. The patient's blood group was A, Le(a-b+), secretor. The serum contained so abnormally large amounts of A substance that it was difficult to determine the ABO blood of the patient's red cells. Using neutralization of anti-A, the ovarian cyst fluid was estimated to contain about 4,000 and 1,500 times as much substance as the serum before removal of the cyst and ascites, respectively. The A substance in serum reverted to a normal level 13 days after removal of the cyst. Gel infiltration analysis of the serum, ascites and ovarian cyst fluid showed the presence of similar A substance with a molecular weight ranging from one to several millions. These data indicate that A substance from the ovarian cyst entered the blood stream, and disappeared from it after the cyst was removed (half-life: 1 day).
A patient with chronic myeloid leukemia secreted an antibody to blood group glycosyltransferases after ABO-incompatible bone marrow transplantation (B recipient/O donor). Peripheral B lymphocytes from the recipient were transformed with Epstein-Barr virus, and then fused by polyethylene glycol with mouse myeloma cell line P3-X63/Ag8.653. After the cloning of the hybridoma cells, a cell line which produced human IgM antibody to blood group glycosyltransferases was established. The antibody completely neutralized B transferase activity at low concentration, while a larger amount of immunoglobulins was required to neutralize A transferase activity.
Craniocerebral angiography, injecting radiopaque contrast medium through the common carotid arteries under the normal blood pressure, was a very useful way to search the cerebral injuries, especially the location of arterial rupture. We think our post-mortem examination using angiography will open up a new way to investigate cerebral injuries.
In the plasma of a blood group B recipient who was transplanted with a blood group O bone marrow, we investigated an antibody to inhibit the activities of blood group A- and B-glycosyltransferases. When B lymphocytes from the patient were transformed with Epstein-Barr virus, a few clones producing antibodies to B-transferase were obtained.
To estimate postmortem interval (PMI), spontaneous cleavage of the third component of complement (C3) was studied in aged blood and cadaveric blood by crossed immunoelectrophoresis. Using the kinetics of C3 cleavage in vitro described as dC/dt = -kC, where C is the concentration of native C3 at time t and k is a first-order rate constant, Arrhenius' equation, and another equation which assumes a linear drop of body temperature after death, the percentages of C3 cleavage were calculated. There was a significant positive correlation between the calculated percentages and the measured percentages of up to 10% in cadaveric blood. We found that the comparison between the calculated percentage of C3 cleavage for each optional postmortem interval and the measured percentage of up to 10% in cadaveric blood leads to the estimation of PMI. This approach is one step towards the development of an accurate method for determining PMI based on C3 cleavage, that is, on a first-order reaction.
To estimate postmortem interval (PMI), the spontaneous conversion of the native third component of complement (C3) to its derived fragments in whole blood was studied by crossed immunoelectrophoresis. C3 cleavages in vitro at different temperatures showed that the incubation of whole blood at a higher temperature led to a faster conversion of beta 1C (native C3) to beta 1A (C3c). In cadaveric blood, we found a significant positive correlation between percentage of C3 cleavage and PMI. From these results, it is possible to estimate PMI from the ratios of C3 cleavage.
The human gastric cancer cell line MKN 45 was derived from the tumour of a blood group A individual, and was known to express large quantities of blood group A-antigen. Using immunofluorescence we found the MKN 45 cells, donated from the Japanese Cancer Research Resources Bank, consisted of A-antigen positive cells (18%) and A-antigen negative cells (82%). After limiting dilution, wild type and mutant cells were cloned with regard to the expression of a cell surface A-antigen. ELISA was used to detect A-antigen in the cell extract of the wild type cells, but none was evident in those of the mutant cells. However, blood group A-gene-specified transferase activity of the mutant cells was comparable to that of the wild type cells.