A Review of Red Yeast Rice, a Traditional Fermented Food in Japan and East Asia: Its Characteristic Ingredients and Application in the Maintenance and Improvement of Health in Lipid Metabolism and the Circulatory System

Red yeast rice has been used to produce alcoholic beverages and various fermented foods in China and Korea since ancient times; it has also been used to produce tofuyo (Okinawan-style fermented tofu) in Japan since the 18th century. Recently, monacolin K (lovastatin) which has cholesterol-lowering effects, was found in some strains of Monascus fungi. Since statins have been used world-wide as a cholesterol-lowering agent, processed foods containing natural statins are drawing attention as materials for primary prevention of life-style related diseases. In recent years, large-scale commercial production of red yeast rice using traditional solid-state fermentation has become possible, and various useful materials, including a variety of monascus pigments (polyketides) that spread as natural pigments, in addition to statins, are produced in the fermentation process. Red yeast rice has a lot of potential as a medicinal food. In this paper, we describe the history of red yeast rice as food, especially in Japan and East Asia, its production methods, use, and the ingredients with pharmacological activity. We then review evidence of the beneficial effects of red yeast rice in improving lipid metabolism and the circulatory system and its safety as a functional food.

Divergence of metabolites in three phylogenetically close Monascus species (M. pilosus, M. ruber, and M. purpureus) based on secondary metabolite biosynthetic gene clusters

BACKGROUND

Species of the genus Monascus are considered to be economically important and have been widely used in the production of yellow and red food colorants. In particular, three Monascus species, namely, M. pilosus, M. purpureus, and M. ruber, are used for food fermentation in the cuisine of East Asian countries such as China, Japan, and Korea. These species have also been utilized in the production of various kinds of natural pigments. However, there is a paucity of information on the genomes and secondary metabolites of these strains. Here, we report the genomic analysis and secondary metabolites produced by M. pilosus NBRC4520, M. purpureus NBRC4478 and M. ruber NBRC4483, which are NBRC standard strains. We believe that this report will lead to a better understanding of red yeast rice food.

RESULTS

We examined the diversity of secondary metabolite production in three Monascus species (M. pilosus, M. purpureus, and M. ruber) at both the metabolome level by LCMS analysis and at the genome level. Specifically, M. pilosus NBRC4520, M. purpureus NBRC4478 and M. ruber NBRC4483 strains were used in this study. Illumina MiSeq 300 bp paired-end sequencing generated 17 million high-quality short reads in each species, corresponding to 200 times the genome size. We measured the pigments and their related metabolites using LCMS analysis. The colors in the liquid media corresponding to the pigments and their related metabolites produced by the three species were very different from each other. The gene clusters for secondary metabolite biosynthesis of the three Monascus species also diverged, confirming that M. pilosus and M. purpureus are chemotaxonomically different. M. ruber has similar biosynthetic and secondary metabolite gene clusters to M. pilosus. The comparison of secondary metabolites produced also revealed divergence in the three species.

CONCLUSIONS

Our findings are important for improving the utilization of Monascus species in the food industry and industrial field. However, in view of food safety, we need to determine if the toxins produced by some Monascus strains exist in the genome or in the metabolome.

Geographical Distribution of Aedes aegypti aegypti and Aedes aegypti formosus (Diptera: Culicidae) in Kenya and Environmental Factors Related to Their Relative Abundance

The mosquito Aedes aegypti (L.) is the primary vector of various infectious viruses and is typified by a polymorphic color and abundance of white scales on the body. It has been conventionally separated into two subspecies, Ae. aeg. formosus (Walker) (Aaf) and Ae. aeg. aegypti (L.) (Aaa), with Aaf considered a 'sylvan' form and Aaa a 'domestic' form. Because the two subspecies show different susceptibilities to dengue viruses it is important to understand their distribution. In this study, we collected larvae from artificial and natural habitats in southern Kenya and reared them to adults to morphologically identify subspecies. We describe the geographical distribution and relative abundance of Aaa and Aaf in Kenya, and estimate the environmental factors associated with their distributions by GIS using climate and environment data. A total of 5,243 Ae. aegypti adults were collected from 249 sites, with Aaa accounting for 22% of the specimens. The relative abundance of Aaa was higher in coastal areas versus sites in western Kenya. Aaa abundance was also higher in urbanized than forested areas, which is consistent with known ecology. In contrast and inconsistent with previous studies, both Aaa and Aaf were sympatric in artificial and natural habitats. The high relative abundance of Aaa in coastal areas might derive from old populated cities, climate, and/or introduction from abroad.

[Planning of cardiothoracic surgery for chronic kidney disease patients]

Chronic renal failure (CRF) is related to cardiac diseases. Cardiac surgery is also related to postoperative acute kidney injury (AKI). It means heart and kidney have close relationship. We analyzed recent published data to understand how to manage CRF patients undergoing cardiovascular surgeries. We compared endovascular surgery and open procedure for aortic aneurysm, especially about contrast media-related renal damage, On or Off CABG or PCI for ischemic heart disease. We also discussed the relation between cardiopulmonary bypass and AKI and the risk factors causing AKI after CPB. Finally, we discussed prevention and treatment options of CPB related AKI, including furosemide, hANP mannitol, and statin. Published evidence in this area is still insufficient, but many studies are still carried out focusing on postoperative AKI. In the future we may be able to find the best answer for managing CRF patients undergoing cardiovascular surgeries.

Effects of temperature and diet on development and interspecies competition in Aedes aegypti and Aedes albopictus

We asked whether climate change might affect the geographic distributions of Aedes aegypti (L.) and Aedes albopictus (Skuse) (Diptera: Culicidae). We tested the effects of temperature, diet and the presence of congeneric species on the performance of immature stages of these two aedine species in the laboratory. Mosquitoes in three different species-density combinations were reared at four constant temperatures (20 °C, 25 °C, 30 °C, 35 °C) on low- or high-level diets. Of the four temperatures tested, mortality increased only at 35 °C in both species. Mortality was higher on the high-level diet than on the low-level diet at 35 °C, but not at other temperatures. The presence of congeneric species had a significant positive effect on mortality in Ae. albopictus, but not in Ae. aegypti. Both species developed more quickly at higher temperatures within the range of 20-30 °C; development was not enhanced at 35 °C. Population growth of Ae. albopictus was more stable, regardless of diet and temperature; that of Ae. aegypti varied more according to these two factors. These species-specific attributes may help to explain the latitudinal distribution of the mosquitoes and degree of species dominance where they are sympatric.

[History and current issues of anesthesia in Korea]

We report the history and current issues of anesthesia in Korea. Korean medical doctors have to take 1-year internship and 4-year residency to be qualified to take the national examination for a board-certified anesthesiologist. The national examination began in 1963, and there were 3,050 board-certified anesthesiologists as of 2006. The calculated patients who were managed by a board-certified anesthesiologist were 5.8 patients a day. The Korean government adopted nurse-anesthetists in 1973 because of shortage of board-certified anesthesiologists. The Korean Society of Anesthesiologists is now demanding its amendment.

[Complications of internal jugular vein cannulation under ultrasound guidance: report of three]

Internal jugular cannulation with ultrasound guidance has been advocated to decrease its complications. However, there can be serious complications by in-experienced physicians in even ultrasound-guided internal jugular vein cannulation. We report three cases of complications associated with ultrasound-guided internal jugular vein cannulation: puncture of the common carotid artery in two patients and pneumothorax in one.

A pediatric occurrence of crescentic glomerulonephritis associated with antineutrophil cytoplasmic antibodies and mesangial IgA deposits

Antineutrophil cytoplasmic antibody-(ANCA) associated glomerulonephritis usually shows histopathologic features of pauciimmune crescentic glomerulonephritis and occurs late in life. We report a 14-year-old Japanese girl presenting with proteinuria, hematuria and mildly elevated serum creatinine. A renal biopsy specimen demonstrated crescentic glomerulonephritis, immunofluorescence showed mesangial IgA staining. Electron microscopic examination disclosed paramesangial deposits. Serum ANCA against myeloperoxidase (MPO) were detected at high titers. Myeloperoxidase-ANCA-related nephritis accompanied by IgA nephropathy is considered rare in childhood and teen years. Yet, if ANCA assays and detailed electron microscopic examination of renal specimens were performed routinely in patients with rapidly progressive glomerulonephritis, the diagnosis might be more frequent in young patients.

Ambulatory monitoring of behavior in daily life by accelerometers set at both-near-sides of the joint

In this paper we examined a new joint motion monitoring method by use of accelerometers to monitor subjects' detailed motion in daily activities. In this method two accelerometers are set at as near points of both sides around the joint as possible. The difference between these two sensors' outputs mainly depend on the joint angle because the centrifugal and the turning acceleration occurred by the rotation around the joint can be neglected. In the experiments we tried to monitor various subject's behaviors of his upper and lower extremities and whole body motion, and could show this method is useful for the ambulatory monitoring of behavior in daily life.

Evidence for a new sibling species of Anopheles minimus from the Ryukyu Archipelago, Japan

The Anopheles minimus complex is known to comprise at least 2 sibling species (A and C) in Thailand and Vietnam. This study investigated the specific status of An. minimus on Ishigaki Island, the Ryukyu Archipelago, Japan using morphological and genetic analyses. Morphological studies revealed that almost all (99.5%) of the adult mosquitoes are characterized by the humeral pale spot on the costa of their wings, a character that partially differentiates species A and C elsewhere. A high frequency (81.4%) have a pale fringe spot at the tip of vein 1A, a character rarely observed in other An. minimus populations. Significant seasonal variation in the size of wild An. minimus mosquitoes on the island was observed, with the largest size in the winter. Scanning micrographs of the cibarial armature of females from Ishigaki Island revealed that over 90% had cone filaments clearly differing in shape from those of species A or C. The Giemsa-stained metaphase karyotypes of larval brain cells were somewhat similar to those of species A, with a few exceptions, but were very different from those reported for species C. Crossing experiments between species A (CM strain) from Thailand and the progeny of An. minimus from Ishigaki Island (ISG strain) revealed postzygotic genetic incompatibility, although no prezygotic isolation. Hybrid progeny were only obtained from CM female x ISG male. F2 hybrid progeny were not obtained, since the hybrid males were sterile or almost sterile with atrophied testes or abnormal spermatozoa, although the polytene chromosomes of hybrid larvae showed synapsis. The hybrid females backcrossed with either CM or ISG males laid eggs with significantly lowered fertility and viability. The sequence for the D3 region of the 28S gene of ribosomal DNA of the ISG strain differed from those of species A and C. In addition, sequence data from Vietnamese mosquitoes suggest that the An. minimus complex may contain additional species. The morphological, cytogenetic, molecular, and hybridization evidence together suggest the existence of another sibling species of the An. minimus complex on Ishigaki Island, which is provisionally designated An. minimus species E.

Studies on thyroid function in rats subjected to repeated oral administration with kojic acid

To elucidate the effects of kojic acid on thyroid function, the compound was given orally to male rats for 4 weeks at 0, 4, 15, 62.5, 250 and 1,000 mg/kg. In 1,000 mg/kg treatment of kojic acid, the rats showed a slight decrease in motility, inhibition of body weight gain, and a decrease in food consumption. An increase in thyroid weight and a morphological change, i.e., hypertrophy of epithelial cells of the thyroid gland follicles, were observed after 1 week of administration. In addition, the uptake of radioactive iodine from blood into the thyroid gland was enhanced and the TCA-precipitable radioactive iodine in the thyroid gland increased in those rats. However, the rates of the iodination in the thyroid gland did not change during the experiment period. Although serum T4 concentration was low in the rats treated with 1,000 mg/kg kojic acid, it was not observed in any changes in TSH concentration. None of these changes were found in the other groups. These observations suggest that massive administration of kojic acid may decrease blood T4 concentration and that thyroid function may be enhanced compensatorily. On the other hand, the absorption of kojic acid was rapid as manifested by the Tmax of blood concentrations of radioactivity, which was as short as 1.0 +/- 0.0 hr, and the t1/2 was 4.8 +/- 0.3 hr. Blood concentrations of radioactivity disappeared nearly completely at 24 hr after administration. This result indicates that the toxic effect observed on the thyroid gland treated with only the largest dosage of kojic acid may depend on a fast decrease following a transient increase of concentration of the compound in the blood.

[Positive seroconversion syphilis in a patient with acute lymphocytic leukemia after allogeneic bone marrow transplantation]

An acute lymphocytic leukemia patient underwent allogeneic bone marrow transplantation (BMT) from a sibling who was serologically positive for syphilis. After the donor was administered antibiotic therapy, the titration of treponema pallidum hemagglutination (TPHA) decreased from x1260 to x320. Thereafter, the graft consisting of mononuclear cells was transplanted. TPHA of the recipient turned positive on day +63, but became negative 1.5 years after BMT. Although the cause of the seroconversion of TPHA seemed to be the contamination of treponema to the graft, the adoptive transfer could not be ruled out as an another possible cause.

Aortic dissection after aortic valve replacement. Report of a case with an aortocameral fistula

A 58-year-old Japanese woman who had a history of aortic valve replacement for congenital bicuspid valve, was admitted for investigation of facial edema and of pulselessness of the right leg. Physical examination disclosed the patient suffering from a superior vena cava syndrome. On auscultation, a continuous murmur was heard at the left lower sternal border. Computed tomographic scans revealed aortic dissection extending from the ascending aorta to the bifurcation. Echocardiography showed an intimal flap in the dilated ascending aorta, but not abnormal blood flow from the aorta to the right atrium was detected. Cardiac catheterization and aortography, however, allowed a correct diagnosis of aortic dissection with fistula to the right atrium and with obstruction of the right common iliac artery. The patient received emergency aortic root replacement and reconstruction of the coronary arteries and then recovered uneventfully.

Total aortic replacement in a patient with mega aorta syndrome--a case report

A 64-year-old woman without manifestations of Marfan syndrome was referred for the close investigation of a pulsatile abdominal mass. Computed tomographic scans and magnetic resonance images revealed aneurysmal dilatation of the entire aorta, including the ascending aorta and extending to the bifurcation of the aorta, as well as tortuousness of the thoracoabdominal and abdominal aorta. Digital subtraction angiography also showed aneurysmal dilatation of the entire aorta and trivial aortic regurgitation. However, aortic annular dilatation was not found by echocardiography or aortography. The entire aorta was replaced in two stages. First, graft replacement of the ascending aorta, except for the sinus segment, and the aortic arch was performed using an elephant trunk technique under hypothermic cardiopulmonary bypass with selective cerebral perfusion. Twelve weeks later, the remaining aorta, including the descending aorta and extending to the common iliac artery on the right side, and to the common femoral artery on the left side, was replaced with a partial cardiopulmonary bypass using femoral artery and vein cannulation. We believe that patients with mega aorta syndrome are best treated by total aortic replacement. The results in the present case indicate that the elephant trunk technique is useful for extensive aortic replacement in stages, and greatly facilitates the second stage operative procedures.

Astrocytoma linked to familial ataxia-telangiectasia

A 7-year and 11 month-old girl with cerebellar astrocytoma linked to familial ataxia-telangiectasia (AT) is presented. She was born as the 7th girl of a woman with aortic arch syndrome. Two elder sisters of the patient have ataxia telangiectasia. She had immunodeficiency, and cerebellar ataxia, but had no oculocutaneous telangiectasia. The risk of cancer developing in AT patients is about 1,200 times greater than that in age-matched controls. With regard to central nervous system tumours, seven primary tumours have been reported, such as 3 cases of medulloblastoma and 4 cases of glioma. Members of AT families who were under the age of 45 had a risk of dying of a malignant neoplasm five times greater than in the general population. However, there were no reports of glioma in AT families. In this case, it is suggested that IgA deficiency linked to familial AT may have contributed to the development of astrocytoma.

Surgical treatment for acute aortic dissection and coexistent degenerative aortic aneurysm. Report of three cases

Acute aortic dissection occurring in an aorta previously afflicted with degenerative, atherosclerotic is unusual. We report three cases with acute aortic dissection (DeBakey type III-b) occurring in an aorta which had a preexistent degenerative aortic aneurysm. Two of the three patients had acute aortic dissection originating from the distal end of the degenerative aneurysm, and the remaining one had the acute aortic dissection and degenerative aneurysm at different segments of the aorta. Since the risk of rupture is likely to be much higher in the patients with coexistence of acute aortic dissection and degenerative aortic aneurysm, compared with patients with DeBakey type III acute aortic dissection alone, we believe that a prompt and aggressive surgical approach is essential to prevent rupture, and that digital subtraction angiography (DSA) is more helpful in making a correct diagnosis and in helping to decide surgical procedures and supportive methods than other noninvasive diagnostic procedures.

Obstruction of the St. Jude Medical valve--diagnostic and therapeutic values of cineradiography

Between 1984, and 1992, we observed 8 patients with an obstructed St. Jude Medical (SJM) valve. Of these, 1 had an obstructed SJM valve in the aortic position, 3 in the mitral position, and 4 in the tricuspid position. Diagnosis of obstruction of the SJM valve was made by cineradiography combined with echocardiography in all 8 patients. Restriction or absence of movement of the leaflet of the SJM valve was observed by cineradiography in all of the 8 patients. Normal range of leaflet mobility of the SJM valve was measured by conventional cineradiography in 70 patients with a normal SJM valve, and the results were compared with the leaflet mobility obtained from the 8 patients with an obstructed SJM valve. In this study, leaflet function in the obstructed SJM valve was strikingly abnormal, with both opening and closing angles, and leaflet motion clearly outside the normal range. Of the 8 patients, 4 underwent urgent prosthetic valve replacements after cineradiography and echocardiography were carried out. Thrombolysis using urokinase was performed in 4 patients, and this treatment was successful in 1 patient. Efficacy of thrombolytic therapy was evaluated by repeat cineradiography. Three of the 4 patients who received thrombolysis showed no significant improvement of leaflet mobility after at least 72 hours of thrombolytic therapy, and finally required surgical correction for the obstructed SJM valve. We believe that cineradiography combined with echocardiography is the optimal method for the diagnosis of obstruction of the SJM valve, and to follow the effect of thrombolytic therapy on prosthetic valve function.(ABSTRACT TRUNCATED AT 250 WORDS)

[Partial brachiocephalic perfusion in aortic arch replacement]

Twenty patients with aneurysm or dissection of the aortic arch underwent surgical treatment using partial brachiocephalic perfusion (PBP). The right subclavian artery (SA) and common femoral artery were separately cannulated and perfused by individual pump heads. The flow to SA was 4.5-11 (9.9 +/- 1.4) ml/min/kg. The mean distal stump pressure of the left superficial temporal arteries before beginning the CPB were 36-64 (50.6 +/- 8.3) mmHg. The rectal temperature during PBP was maintained at 20.1-25.0 degrees C. The PBP time ranged 32 to 157 min. We studied the oxygen saturation of left internal jugular vein (SjO2) and cerebral circulatory index (CCI) during the PBP. SjO2 ranged from 72.9 to 99.4% and CCI were maintained at more than twice the CCI measured before beginning the CPB. We applied this simplified method (PBP) to the 20 patients with aortic aneurysms. No neurological complication were seen in these 19 patients without one patient. These clinical studies suggest that the PBP under hypothermic CPB is a safe and reliable method of cerebral protection for replacement of the aortic arch.

Human recombinant interleukin-1 beta-mediated growth inhibition of cultured malignant glioma cells

The effect of human recombinant interleukin-1 beta (hrIL-1 beta) on tumor growth was studied in eight glioma cell lines. hrIL-1 beta inhibited growth in all cell lines, but to varying extents. Two cell lines were suppressed by 0.5 ng/ml hrIL-1 beta, and three cell lines required 20 ng/ml. hrIL-1 beta also induced morphological changes and increased F-actin contents. hrIL-1 beta-treated cells demonstrated multipolar shapes and numerous processes with a greater number of cell-cell contacts 24 hours after treatment. Fluorescence microscopy revealed that these processes contained a large amount of polymerized F-actin. These results suggest that hrIL-1 beta-mediated growth inhibition may be related to the differentiation of glioma cells.

Analysis of retained ventricular shunt catheters

To identify the causes of ventricular shunt catheter retention, 42 shunt removals in 28 patients in our neurosurgical clinic from 1982 to 1991 were analyzed. The mean patient age was 13.8 years (2 mos-78 yrs), and mean shunt duration was 20.1 months (0.5-94 mos). There were nine retained ventricular catheters, including five with obstruction of the ventricular catheter. Shunt duration was significantly longer compared with the unretained group. Three retained ventricular catheters were stained by HE for histological examination. Light microscopy showed the inner lumen of catheters filled with granulomatous connective tissue and reactive glial tissue, and giant cell reaction to silicone material. Scanning electron microscopy of two catheters found peeling on the inner surface of the catheter, evidence of aging of the material. Granulomatous connective tissue and glial tissue reaction to aged silicone are suggested as the cause of catheter retention.

[The motility of IL-2 activated lymphocytes into malignant glioma]

The effects of glioma culture supernatant (GCS) and interleukin-2(IL-2) on the motility of autologous stimulated lymphocytes (ASL) were studied by using collagen gel system, chemotaxic chamber system and flow cytometric analysis. GCS inhibited the migration of ASL into collagen gel. It enhanced the ASL motility and the expression of CD 26 antigen on the cell surface. IL-2 inhibited the migration of ASL into collagen gel and had no influence on the motility of ASL, but enhanced the expression of CD 26 antigen. On the other hand, a clinical glioma specimen showed limited depth of ASL migration when injected into the tumor cavity in addition to the formation of fibrin like membrane on its surface and a layer of degenerated ASL under it. To make ASL therapy more effective to malignant glioma, the following measures should be recommended; 1) inject adequate volume of IL-2 into tumor cavity, 2) reduce the frequency of ASL administration, 3) wash out of glioma secreting factors, degenerated ASL and glioma cells in addition to reduce the volume of tumor tissue.

Lymphocytic adenohypophysitis with sudden onset of diabetes insipidus in menopausal female--case report

A rare case of a postmenopausal (60-year-old) female with lymphocytic adenohypophysitis manifesting as a sudden onset of diabetes insipidus is reported. Magnetic resonance imaging with gadolinium-diethylene-triaminepentaacetic acid enhancement showed a spherical lesion, approximately 1 cm in diameter, in the sella turcica and a thickened, deviated pituitary stalk. The abnormal tissue was totally removed. Histological examination showed marked infiltration of lymphocytes and plasma cells. Postoperatively, the pituitary stalk became normal. Preoperative differentiation of lymphocytic adenohypophysitis from pituitary adenoma is extremely difficult, and biopsy is essential.

[Arterial to end-tidal carbon dioxide difference during laparoscopy]

Arterial as well as end-tidal PCO2 (PaCO2, PetCO2), and arterial to end-tidal PCO2 difference (P(a-ET)CO2) were studied in 16 ASA-I patients anesthetized for laparoscopy under controlled ventilation. Using constant ventilation throughout the procedure, PaCO2 and PetCO2 increased significantly (P less than 0.01) to the maximum level (about 10 mmHg above the control level) within 22 min after CO2 insufflation, along with significant increase in mean arterial pressure and heart rate. There was a statistically significant correlation between PaCO2 and PetCO2 at the time of control (before surgery), at the time of maximum PetCO2 and 30 to 60 min after CO2 insufflation (P less than 0.01). Although mean P(a-ET)CO2 remained relatively constant during the procedure, a statistically significant correlation between PaCO2 and P(a-ET)CO2 was found at the time of maximum PetCO2 after CO2 insufflation (r = 0.71, P less than 0.01). These results suggest that when PvCO2 is increasing by CO2 insufflation, P(a-ET)CO2 depend on relative ventilation efficacy.

Treatment of metastatic brain tumor from esophageal carcinoma--report of four cases

Metastasis to the brain from esophageal carcinoma is rare. Recently we had four cases, all treated by tumor removal. Three received postoperative whole or local brain irradiation. Anticancer pellets were implanted in two. The postoperative 1-year survival rate was 37.5%, which suggests the prognosis is not worse than for other metastatic brain tumors.

[Cerebrospinal fluid transfer of cefbuperazone in the blood-brain barrier lesions of neurosurgical patients]

Cefbuperazone (CBPZ) was given in 15 patients after surgery. There was no infections except for 1 case in which signs of infections were suspected. As side effects, slight elevations in hepatic transaminase levels were observed in 3 patients during the CBPZ chemotherapy. CBPZ concentrations in 7 patients were studied. The subjects were divided into 3 groups according to CT finding during the chemotherapy to correlate CBPZ concentrations to degrees of blood-brain barrier lesions; Group I: no enhancement, Group II: mild or focal enhancement, Group III: diffuse and marked enhancement. It was interesting to note that the more marked enhancement were obtained, the higher levels of CSF concentration of CBPZ.

In vitro studies on some parameters of the binding of the rat hemopexin--heme complex with the hepatic membrane receptor

The binding of [125I]Hpx--heme with the rat hepatic plasma membrane receptor was studied at 37 degrees C as well as different parameters such as plasma membrane concentration, calcium dependence, optimal pH and specific binding. A Scatchard plot revealed the existence of one binding for [125I]Hpx--heme on the isolated liver plasma membrane with a Kd = 3.2 X 10(-8) M.

Kinetic aspects of hemoglobin.haptoglobin-receptor interaction in rat liver plasma membranes, isolated liver cells, and liver cells in primary culture

125I-Hemoglobin.haptoglobin injected intravenously into rats was incorporated into liver parenchymal cells as evidenced by a cell separation technique. A mixture of freshly isolated liver parenchymal and nonparenchymal cells failed to internalize and degrade the 125I-hemoglobin.haptoglobin added, although it retained the ability to bind the molecule. The liver parenchymal cells in primary culture also lacked the ability to degrade 125I-hemoglobin.haptoglobin, although they bound the molecule more extensively as compared with the freshly isolated liver cells. It was confirmed that the 125I-hemoglobin.haptoglobin which was bound to the freshly isolated liver parenchymal cells localized on the outer surface of liver plasma membranes. Scatchard plots revealed the existence of two binding sites for 125I-hemoglobin-haptoglobin on the isolated liver plasma membrane: an apparent high affinity binding site (Kd = 1.3 X 10(-7) M) and an apparent low affinity binding site (Kd = 4.0 X 10(-6) M) at 37 degrees C. In contrast, freshly isolated liver parenchymal cells had only an apparent low affinity binding site (Kd = 1.4 X 10(-6) M) at 37 degrees C. Impairment of the apparent high affinity binding site during the isolation procedure with collagenase seemed to be related to loss of the ability to internalize and degrade the 125I-hemoglobin.haptoglobin molecules into the freshly isolated liver parenchymal cells or liver parenchymal cells in primary culture.

Catabolism of globin-haptoglobin in liver cells after intravenous administration of hemoglobin-haptoglobin to rats

The intracellular site of uptake and degradation of globin-haptoglobin, the protein moiety of hemoglobin-haptoglobin, in rat liver cells was investigated in vivo. Hemoglobin-haptoglobin, administered intravenously to rats, is cleared from circulation and incorporated exclusively into liver parenchymal cells through the receptor specific for the molecule (Kino, K., Tsunoo, H., Higa, Y., Takami, M., Hamaguchi, H., and Nakajima, H. (1980) J. Biol. Chem. 255, 9616-9620). Intrahepatocellular distribution of radioactivity was determined after intravenous administration of (125I-hemoglobin)-haptoglobin or hemoglobin-(125I-haptoglobin) to rats. The 125I-labeled hemoglobin-haptoglobin was incorporated first in organelles of low density (density range, 1.05-1.07 g/ml) recovered in Golgi subfractions of the liver cells in a substantially intact form. The organelles progressively acquired a higher density, presumably through fusion with primary lysosomes. In the resulting organelles of high density (density range, 1.07-1.15 g/ml), which are probably secondary lysosomes, hemoglobin-haptoglobin first dissociated symmetrically to yield two 82,000-dalton subunits by a limited proteolysis, and further digestion of the constituent polypeptide chains seemed to proceed thereafter in the organelles during the transport process across the cells.

Hemoglobin-haptoglobin receptor in rat liver plasma membrane

The presence of a receptor specific for the hemoglobin . haptoglobin complex is demonstrated in rat liver plasma membranes. Hemoglobin . haptoglobin complex, administered intravenously to rats, was cleared from the circulation at a constant rate with exclusive incorporation of the molecule into hepatocytes. This incorporation was unaffected by the simultaneous injection of asialoglycoprotein or heme . hemopexin complex. In vitro experiments with isolated liver plasma membranes indicated the absence of competitive binding of these molecules to the membrane and suggested that this receptor might recognize an altered conformation of the haptoglobin moiety of the complex resulting from the binding with hemoglobin. These observations suggest that the mechanism of recognition and binding of hemoglobin . haptoglobin complex by the receptor is different from that of the asialoglycoprotein receptor or heme . hemopexin receptor.