Peroxisome proliferator enhances gene expression of cellular retinol-binding protein, type II in Caco-2 cells

Both the mRNA and protein of cellular retinol-binding protein, type two (CRBP(II)) are induced in rat intestine by high fat (corn oil) diet (Biochim. Biophys. Acta 1200, 34-40, 1994) as well as by dietary unsaturated long-chain fatty acids (J. Nutr. 125, 2039-2044, 1995). To gain an insight into the mechanism for this induction, we investigated whether CRBP(II) gene was activated by exposure of the human intestinal cell line, Caco-2 to a peroxisome proliferator (clofibric acid) and/or 9-cis retinoic acid. Northern blot hybridization revealed that Caco-2 cells endogenously expressed the mRNAs of peroxisome proliferator-activated receptor alpha (PPARalpha) and retinoid X receptor alpha (RXRalpha). The expression of the genes encoding CRBP(II), PPARalpha, and RXRalpha increased progressively during differentiation of Caco-2 cells. The cells exposed to 100 microM clofibric acid exhibited 70% greater CRBP(II) mRNA and the exposure of the cells to 100 microM clofibric acid in combination with 100 microM 9-cis retinoic acid exhibited 130% greater CRBP(II) mRNA level, indicating that the effect of the combination of them was additive. Neither PPARalpha mRNA nor RXRalpha mRNA level was enhanced by clofibric acid. In conclusion, our data suggested that the CRBP(II) gene expression may be enhanced by an activation of PPARalpha-RXRalpha heterodimer through some putative metabolite(s) formed via fatty acid-related metabolic pathway in the clofibrc acid-treated cells.

Cloning of chick cellular retinol-binding protein, type II and comparison to that of some mammals: expression of the gene at different developmental stages, and possible involvement of RXRs and PPAR

We cloned chick cellular retinol-binding protein, type two (CRBP II) cDNA and compared it with those of some mammals. The deduced amino acid sequence showed that chick CRBP II was one amino acid greater in size than those of mammals, and the nucleotide sequence of chick CRBP II shared 72%-75% similarity with those of mammals. RNA blot hybridization analysis showed that CRBP II transcript of 0.7 kb was first detected in the duodenum of day-18 embryonic chick, and exhibited a rapid increase during 24 hr around the hatching. Northern blot hybridization also revealed that the transcripts of two types of retinoid X receptors (RXR alpha and RXR gamma) and peroxisome proliferator-activated receptor (PPAR) were expressed in the chick duodenum at hatching. The organ culture of day 16 embryonic chick duodenum showed that the addition of 9-cis retinoic acid in the medium caused a significant increase in CRBP II mRNA levels. In addition, arachidonic acid, from which putative ligands for PPAR were supposed to be generated, was accumulated around hatching in the duodenum. The results may suggest that the abrupt increase of the CRBP II gene expression in the chick duodenum around hatching may be related with RXRs and/or PPAR.

A possible role of a nuclear factor NF-LPH1 in the regional expression of lactase-phlorizin hydrolase along the small intestine

Lactase-phlorizin hydrolase (LPH), an enterocyte-specific disaccharidase, displays not only a post weaning decline but also regional differences in the small intestine. To investigate the mechanisms of regional LPH expression along the small intestine, the correlation between LPH mRNA abundance, lactase activity and the amount of a nuclear factor (NF-LPH1) binding to a cis-element was determined in various intestinal segments of suckling and adult rats. In suckling rats, both LPH mRNA and lactase activity were expressed at maximum in the jejunum, but they were hardly detected in the colon. In adult rats, both LPH mRNA and lactase activity were the highest in the jejunum and virtually absent in the ileum. Lactase activity and LPH mRNA abundance in suckling rats were 2-3 times more than those of adult rats in all regions of the small intestine. An electromobility shift assays of nuclear proteins revealed that NF-LPH1 was present in rat small intestine as well as in Caco-2 cells. The amount of NF-LPH1 binding to the cis-element was also approximately 2-fold more in the intestinal nuclear extracts of suckling rats than that of adult rats. NF-LPH1 was detected in all regions of the small intestine in both suckling and adult rats. In both cases, the amounts of NF-LPH1 binding to the cis-element increased from the duodenum to upper jejunum, and decreased toward the ileum. The coordinate postnatal declines of LPH mRNA and NF-LPH1 expression in various regions of the small intestine suggest that NF-LPH1 might be involved not only in the regulation of postnatal LPH gene expression but in region-specific LPH gene expression as well.

Perilla oil prevents the excessive growth of visceral adipose tissue in rats by down-regulating adipocyte differentiation

We examined the effect of dietary oils with different fatty acid compositions on the growth of visceral adipose tissue in rats. Rats were fed for 4 mo starting at weaning a basal diet containing (12 g/100 g diet) perilla oil rich in (n-3) polyunsaturated fatty acids (PUFA), safflower oil rich in (n-6) PUFA, olive oil rich in monounsaturated fatty acid, or beef tallow rich in saturated fatty acids. The amount of food consumed and body weight gain did not differ among the four dietary groups. The weight of the epididymal fat pad and the serum triglyceride concentration in perilla oil-fed rats were significantly lower (P < 0.05) than those of olive oil- and beef tallow-fed groups. The product of [(volume of individual adipocytes) x (number of adipocytes in epididymal fat pad)], which presumably represents total adipocyte volume in the fat pad, was significantly lower (P < 0.05) in perilla oil-fed rats than in beef tallow- and olive oil-fed groups. Expression of the late genes of adipocyte differentiation, peroxisome proliferator-activated receptor alpha, adipocyte P2 and adipsin, was significantly (P < 0. 05) down-regulated in epididymal fat tissue of rats that had been fed perilla oil rather than beef tallow or olive oil, whereas expression of the early gene, lipoprotein lipase, was not significantly affected. Greater levels (P < 0.05) of (n-3) PUFA in the membrane phospholipid fraction of the fat tissue were observed in perilla oil-fed rats than in the other dietary groups. These results suggest that perilla oil or (n-3) PUFA prevents excessive growth of adipose tissue in rats at least in part by suppressing the late phase of adipocyte differentiation.

Establishment of a novel host, high-red yeast that stably expresses hamster NADPH-cytochrome P450 oxidoreductase: usefulness for examination of the function of mammalian cytochrome P450

A novel strain of Saccharomyces cerevisiae useful for expression studies of mammalian microsomal cytochrome P450s was established and named High-red yeast. Hamster NADPH-cytochrome P450 oxidoreductase (P450 reductase) cDNA to be introduced into yeast was isolated from a hamster liver cDNA library. The cDNA was 2421 bp long and contained an entire coding region for 667 amino acids. The NH2-terminal amino acid sequence deduced from the hamster P450 reductase cDNA was identical with that of the enzyme purified from hamster livers except for deletion of the initial methionine. A delta-sequence derived from yeast retrotransposon Ty was cloned and used as a sequence for homologous recombination in a yeast genome. S. cerevisiae YPH500 was transformed with a multi-integration cassette containing the expression unit of the hamster P450 reductase and the delta-sequence. The transformant showing the highest activity of the P450 reductase was named High-red yeast. High-red yeast carried more than six copies of the multi-integration cassettes in a single chromosome and retained the multi-integration cassettes over a period of 100 generations under nonselective culture conditions, indicating that this yeast was a mitotically stable transformant. The microsomes prepared from High-red yeast had 20 times the P450 reductase activity of the microsomes prepared from the parental yeast. Due to the high activity of the hamster P450 reductase, the 7-ethoxycoumarin deethylase activity of mouse CYP1A1 expressed in High-red yeast was 250 times higher than the activity of mouse CYP1A1 expressed in the parental yeast.

Maltitol increases transepithelial diffusional transfer of calcium in rat ileum

We explored the mechanism whereby maltitol causes an increase of calcium absorption in the lower small intestine using everted ileal segments of rats. Under the calcium concentrations tested (1-20mM), which enabled us to assess the diffusional calcium transfer, maltitol in the mucosal-side medium (100mM) caused a 155% greater transepithelial calcium transfer as compared with the segments incubated without sugars. The maltitol-induced increment of calcium transfer was significantly higher than those elicited by glucose, sorbitol and maltose, and this increase was completely inhibited by W7, a calmodulin antagonist. Thus, our results suggest that maltitol might modulate the permeability of calcium through paracellular path, which possibly involves the activation of calmodulin.

Lack of lecithin: retinol acyltransferase activity in chick lungs

Our previous study revealed that no retinyl esters were detectable in chick and hen lungs, suggesting that the retinol esterification system may be absent in these tissues. This possibility encouraged us to investigate whether chick lungs exhibit the activity of a retinol esterifying enzyme, i.e., lecithin: retinol acyltransferase (LRAT). The LRAT activity was assayed with dilauroyl phosphatidylcholine and either complex of retinol-cellular retinol-binding protein, type two or retinol-cellular retinol-binding protein in microsomal preparations of lung, duodenum and liver of 7-day-old chicks. Relatively high levels of LRAT activity were present in the duodenum and the liver of chicks as well as in the rat lung. However, the chick lung exhibited no LRAT activity. The lungs of both rat and chick showed similar and low levels of acyl-CoA: retinol acyltransferase (ARAT) activity, but only rat lung, but not chick lung, contained a detectable amount of retinyl esters. Thus, the retinyl ester storage in the lung seems to depend on the presence of LRAT activity in the lung, but it is independent of the presence of ARAT activity in the lung. The absence of LRAT activity and retinyl esters in the chick lung suggests that the retinol in the chick lung may not be provided from retinyl ester storage, and the retinol transferred directly from serum should be utilized to generate retinoic acid.

Relationship between perinatal appearance of cellular retinol-binding protein, type II and retinal reductase activity in chick liver

To explore a role of the transiently appearing cellular retinol-binding protein, type II (CRBP(II)) in perinatal chick liver, we have examined whether the relationships exist among the perinatal changes in hepatic CRBP(II) protein and mRNA levels, retinal reductase activity and beta-carotene levels in liver and serum. Northern blot analysis for hepatic CRBP(II) revealed a transient expression of CRBP(II) mRNA around hatching. The protein of CRBP(II) was also expressed transiently and the highest levels of CRBP(II) were found in the livers 1-3 days after birth. The retinal reductase activity was very low at embryonic age, but its activity rapidly rose at hatching, peaking at 1 day after birth, followed by a gradual decrease to a lower level in 7-day-old chicks. This perinatal pattern of the retinal reductase activities was similar to the pattern of transient appearance of the hepatic CRBP(II), and was also paralleled to the developmental changes in serum and liver beta-carotene concentrations. These findings suggest that hepatic CRBP(II) transiently appearing during the perinatal period may involve in metabolizing hepatic beta-carotene, directing the retinal to the retinal reductase and leading further to the subsequent esterification of the converted retinol.

Preoperative disseminated intravascular coagulation (DIC) associated with aortic aneurysm--does it need to be corrected before surgery?

Disseminated intravascular coagulation (DIC) is one of the complications accompanying aortic aneurysm. We herein report four patients with aortic aneurysm who had DIC preoperatively. In all four cases, DIC was corrected immediately after surgery; however, in two cases, DIC could not be corrected preoperatively. This prompted us to reconsider the importance of correcting DIC before surgery. Of the four cases reported in this paper, DIC existed even at the time of surgery in two cases, in spite of meticulous treatment with heparin and/or protease inhibitor; however, the DIC could be removed postoperatively even in these two cases. Surgeons should not waste time with intensive DIC treatment preoperatively. If the DIC cannot be corrected within more than 2 weeks of meticulous treatment, surgeons should then perform surgery on the patient. In addition, it is also essential to ensure that the DIC is due to the aneurysm itself and that no other disease processes have been overlooked.

Dietary maltitol increases calcium content and breaking force of femoral bone in ovariectomized rats

Maltitol is a disaccharide alcohol generated by hydrogenation of maltose and exhibiting resistance to intestinal disaccharidases. We demonstrated previously that maltitol stimulates transepithelial transport of calcium in the ileum, accompanied by an elevation of intestinal calcium absorption as well as calcium retention in the body. In this study, we examined whether the maltitol-induced increase in intestinal calcium absorption leads to an alteration of the physical properties of bones in rats subjected to ovariectomy. We used this study as a simulation model for postmenopausal females who are at risk for osteoporosis. Following the intake of a low-calcium diet for 28 d ovariectomized rats were fed diets containing either 10% maltose (control) or 10% maltitol, together with increased amounts of calcium (0.3% in Experiment 1 and 1.2% in Experiment 2) for 21 d. Balance studies performed during the final 5-d (Experiment 1) or 2-d (Experiment 2) period of the experiments showed that maltitol increased intestinal calcium absorption and retention. The breaking force of femoral bones was significantly elevated (by 5-7%) in animals fed the maltitol diet compared with that in rats fed the maltose diet. The calcium content in the femoral bones as well as the mineral bone density of the tibial metaphysis was also elevated in rats fed the maltitol diet. These results indicate that maltitol stimulates the intestinal absorption of dietary calcium leading to an increase in calcium content in the bone, and coinciding with the elevation of the breaking strength of the bone in ovariectomized rats.

Unsaturated fatty acids regulate gene expression of cellular retinol-binding protein, type II in rat jejunum

We have shown that cellular retinol-binding protein, type II (CRBP II) mRNA and its protein levels are elevated in the jejunum of rats fed a diet rich in long-chain triacylglycerols. In the present study, we explored which types of fatty acids modulate CRBP II gene expression. Rats previously fed a low fat, high starch diet were force-fed a basal fat-free diet or the diet supplemented with 0.21 mol/L of various fatty acids (i.e., caprylic, palmitic, stearic, oleic, linoleic and alpha-linolenic acids). Force-feeding a diet containing linoleic acid produced an elevation of CRBP II mRNA levels in rats in both a dose-dependent (0.053-0.21 mol/L) and time-dependent (up to 6 h) manner. Among fatty acids tested, all unsaturated fatty acids (oleic, linoleic and alpha-linolenic acids) were able to enhance CRBP II mRNA levels by 54-63% within 6 h, whereas a medium-chain fatty acid (caprylic acid) and a saturated fatty acid (stearic acid) elicited little effect on the CRBP II mRNA levels; palmitic acid produced only a small elevation (16%) of the CRBP II mRNA level. Transcripts of both retinoid X receptor alpha and peroxisome proliferator-activated receptor (PPAR), which are thought to interact as a heterodimer with the cis-element located in the CRBP II promoter and to be activated by 9-cis retinoic acid and long-chain fatty acids, respectively, were constitutively expressed in the rat jejunum.(ABSTRACT TRUNCATED AT 250 WORDS)

Consumption of excess vitamin A, but not excess beta-carotene, causes accumulation of retinol that exceeds the binding capacity of cellular retinol-binding protein, type II in rat intestine

We assessed the effects of excess dietary vitamin A or beta-carotene on the cellular retinol-binding protein, type II [CRBP(II)] level and activities of lecithin: retinol acyltransferase (LRAT) and acyl-CoA:retinol acyltransferase (ARAT) in rat intestine. Male rats were fed for 7 d diets containing amounts of retinyl acetate or beta-carotene that were 1 (control), 10, 100 and 1000 times the NRC recommended requirement. No responses of the jejunal CRBP(II) level to an intake of excess vitamin A or beta-carotene were observed. The unesterified retinol and retinyl palmitate concentrations in the jejunum were small in rats fed 10 times the vitamin A requirement but they were significantly greater in rats fed 100 and 1000 times the vitamin A requirement than in controls. The molar ratio of unesterified retinol/CRBP(II) was < 1 for the controls and the group fed 10 times the vitamin A requirement, but > 3 for the group fed 100 times the requirement and > 19 for the group fed 1000 times the requirement. The LRAT activity was significantly greater in rats fed 1000 times the vitamin A requirement compared with all other groups, but ARAT activity was unaffected. Consumption of excess beta-carotene did not alter LRAT or ARAT activity, and led to a very small deposition of unesterified retinol and retinyl palmitate in the jejunum. Because CRBP(II) may play an important role in preventing the toxic effect of unbound retinol in the small intestine, consumption of excess vitamin A in amounts < 10 times the NRC recommended requirement may not cause a disturbance of the absorptive cell function.(ABSTRACT TRUNCATED AT 250 WORDS)

Diet-induced changes in gene expression of lactase in rat jejunum

To explore the mechanisms by which jejunal lactase activity is modified by carbohydrate and/or fat intake, mRNA levels and the absolute synthesis rate of lactase-phlorizin hydrolase (LPH) were determined in 6-wk-old rats that were fed either low-starch diets containing long-chain triacylglycerol (LCT, 73% energy as corn oil) or medium-chain triacylglycerol (MCT, 66% energy as MCT, 7% energy as corn oil), or a high-starch diet (70% energy as cornstarch) for 7 days. LPH mRNA levels in the jejunum were similar between LCT-fed and MCT-fed rats, but animals fed the high-starch diet exhibited a greater (2x) LPH mRNA level than other groups. The absolute synthesis rate of LPH, estimated by the flooding dose technique using [3H]phenylalanine, was greater (2.4x) in rats fed the high-starch diet than in other groups. A short-term force-feeding experiment revealed that sucrose was able to evoke LPH mRNA levels within 12 h but that a nonmetabolizable sugar (alpha-methylglucoside) was unable to enhance it. By contrast, animals fed the high-LCT diet showed a lower (by 30%) lactase activity than rats fed the low-starch, high-MCT diet, which was accompanied by not only a reduction of immunoreactive LPH in brush-border membranes but also a reduction in lactase activity per unit weight of immunoreactive LPH. These results suggest that both gene expression and posttranslational events of LPH might be influenced by dietary manipulations; carbohydrate intake primarily increases LPH mRNA levels, and LCT accelerates inactivation and/or degradation of lactase.

Alterations in coagulation and fibrinolysis after surgery for aortic aneurysm

We investigated the alterations in the coagulation and fibrinolysis systems after aortic aneurysm surgery under cardiopulmonary bypass (CPB) while using newly developed "molecular markers". Fibrinogen and antithrombin III (AT-III) decreased after surgery but returned to normal values within three days. The thrombin-antithrombin III complex (TAT) and plasmin-alpha-2-plasmin inhibitor complex (PIC) both showed increased values even preoperatively, which indicated that coagulation and fibrinolysis were activated in some patients with an aortic aneurysm. Both markers maintained a high level for at least 14 days after surgery. The fibrin degradation product (FDP) also showed an increased value before and after surgery. These results apparently showed that coagulation/fibrinolysis had already been activated in some patients and maintained such a state for at least 14 days after surgery. The relation of activated system and postoperative organ dysfunction as well as the means to suppress such activation are also discussed.

Dietary regulation of sucrase-isomaltase gene expression in rat jejunum

We have previously demonstrated that intake of fat as well as carbohydrate affects the activity and immunoreactive amount of sucrase-isomaltase (S-I) in rat jejunum. To examine whether diet-related changes in sucrase and isomaltase activities are accompanied by the variations of sucrase-isomaltase mRNA levels, 7-week-old rats were fed either a high-long-chain triacylglycerols diet (73 energy% as corn oil), a high-medium-chain triacylglycerols (MCT) diet (66 energy% as MCT, 7 energy% as corn oil) or a high-carbohydrate diet (70 energy% as corn starch) for 7 days. Northern blot analysis revealed that S-I mRNA levels were abundant in the jejunum of rats fed the high-MCT diet; the levels were similar to those in the rats fed the high-carbohydrate diet. Force-feeding a high-sucrose diet (40 energy% as sucrose) brought about a parallel rise in both S-I mRNA and sodium/D-glucose cotransporter (SGLT1) mRNA levels within 12 h. Force-feeding the high-MCT diet also produced an elevation of S-I mRNA and SGLT1 mRNA. However, force-feeding a diet containing alpha-methylglucoside, a non-metabolizable but actively transported sugar, did not increase S-I mRNA or SGLT1 mRNA level; sucrase activity was nevertheless elevated by feeding alpha-methylglucoside diet. These results suggest that not only carbohydrate intake but also MCT intake might influence S-I mRNA and SGLT1 mRNA levels in the jejunum, presumably through common metabolite(s) of carbohydrates and MCT, and that carbohydrate may play another role in enhancement of the sucrase activity through modulation of translation and/or posttranslational modifications of the sucrase-isomaltase complex.

[A case of aortic valve replacement and aorto-coronary bypass with left lung collapse due to thoracoplasty]

A 64-year-old woman was attacked cardiac and respiratory failure in 3 times within a year. Aortic regurgitation (III degrees) and left anterior descending coronary artery 90% stenosis was recognized. %VC: 33% and %FEV1.0 75% were established. Aortic valve replacement (SJM 23 nm) and coronary arterial bypass grafting (SVG) were performed with cardiopulmonary bypass. Post operative course was no trouble and patient was discharged within 60 days.

Dietary carbohydrate and fat independently modulate disaccharidase activities in rat jejunum

The role of carbohydrate and fat in diet-induced modifications of jejunal disaccharidase activities was evaluated with an isoenergic diet containing a nonmetabolizable sugar, alpha-methylglucoside. Rats previously fed a high fat, low starch diet or a high starch low fat diet were force-fed three times over 12 h isoenergic high fat diets with or without alpha-methylglucoside, or a low fat diet containing alpha-methylglucoside. Regardless of the previous diet fed, force-feeding the high fat, alpha-methylglucoside diet produced significantly greater sucrase and lactase activities in the upper jejunum than force-feeding the high fat diet without alpha-methylglucoside; comparable or only slightly greater sucrase and lactase activities were seen in the lower jejunum. The animals fed the low fat, alpha-methylglucoside diet exhibited significantly greater sucrase and lactase activities in the lower jejunum than did the rats fed the high fat, alpha-methylglucoside diet; a less marked difference (< 30%) was observed between these two groups for disaccharidase activities in the upper jejunum. The lower sucrase and lactase activities observed in the jejunum of animals force-fed the high fat diet after consuming the high starch, low fat diet were accompanied by greater trypsin activity in the lumen of the upper and lower jejunum, suggesting that proteolytic degradation of sucrase and lactase might be stimulated in rats fed the high fat diets. These results suggest that both dietary carbohydrate and dietary fat independently and by different mechanisms modulate jejunal disaccharidase activities.

[Acute dissection of the interatrial septum after re-replacement of the mitral valve--a case report]

A 64-year-old man who had received a Carpentier-Edward mitral valve replacement seven years earlier was seen with dyspnea on exertion. After re-replacement of the mitral valve with SJM prosthesis, the patient developed acute left-sided heart failure on the third postoperative day. Transesophageal echocardiography revealed abnormal lumen posterior to the left atrium with regurgitant flow from the left ventricle. Right and left atriotomy revealed dissection of the interatrial septum and after removal of the prosthesis, communication between the left ventricle and the dissected lumen was recognized. After closing the communicating orifice, SJM prosthesis was again sutured on the mitral annulus with sub-annular pledgets to reinforce the annular attachment. Excessive debridement of the annular tissue was thought to be a causative factor to develop the dissection of the interatrial septum after mitral valve replacement.

[A case of perforated mitral valve aneurysm following aortic valve replacement associated with infective endocarditis]

A case of perforated mitral valve aneurysm following aortic valve replacement associated with infective endocarditis was reported. The patient was a 29-year-old man, who was suffering from high fever, Osler's nodules and headache. A brain abscess was recognized in a computed tomography and 3rd grade aortic regurgitation was recognized in echocardiogram and aortography. Hematological studies suggested the inflammation and gram-positive cocci was incubated from his arterial blood. Then infective endocarditis with aortic regurgitation was diagnosed. AVR was performed following 8 weeks treatment with antibiotics, when he had negative CRP and his blood culture. After the operation, he was received the intravenous antibiotic therapy for 6 weeks and oral antibiotic drugs was given following his hospital discharge. At 6 months after AVR, mitral valve aneurysm was recognized in his echocardiogram. At 30 months after AVR, the perforation of it was revealed and mitral valve replacement was performed with his negative blood culture. The patient was discharged 28th day after MVR. There has been no active inflammation from his first hospital discharge and following days, the mitral valve aneurysm and the perforation was caused by weakened tissue of the anterior mitral leaflet due to sibilant inflammatory change.

Dietary fat regulates cellular retinol-binding protein II gene expression in rat jejunum

Cellular retinol-binding protein II (CRBP II) is an abundant cytosolic protein of intestinal absorptive cells. In this study, we examined whether dietary fat modulates the expression of CRBP II in the small intestine. In the rats fed a diet rich in long-chain triacylglycerols (LCT), both CRBP II mRNA and CRBP II protein levels in the jejunum were more than two-fold greater than in the rats fed a low fat diet and a diet rich in medium-chain triacylglycerols (MCT). The mRNA abundance of a retinoid X receptor (RXR alpha), which is thought to interact with the cis-element located in the CRBP II promoter, was elevated in the jejunum of rats fed high-LCT and high-MCT diets as compared with that of animals fed a low-fat diet, but the levels of RXR alpha mRNA of the LCT diet group was similar to that of MCT diet group. These results suggest that the expression level of the CRBP II gene is not directly related to the RXR alpha expression, and that it might be modulated by long-chain fatty acids or their metabolites.

Effect of dietary fat content on microvillus in rat jejunum

To examine whether dietary manipulation of isoenergic diets might affect microvillar structure of small intestinal epithelial cells, morphological parameters of enterocytes and microvilli in the mid-villus portion of jejunum were determined in the rats fed either high-starch (70 energy %), low-fat (7 energy %) diet or high-fat (73 energy %), low-starch (5 energy %) diet for 7 days. Feeding the high-fat diet produced an increase in the height of villus, in accordance with the elevated jejunal mucosal weight and total protein contents as compared with the high-starch diet. No appreciable change in crypt depth occurred. Scanning electron microscopy of jejunal epithelial cells revealed that the morphometrical parameters of the villus cells were unchanged by the diets, but the microvillar structure of each villus cell was influenced by the diets; the animals fed the high-fat diet exhibited a reduced length (28%) of microvillus with a slight increase (12%) in diameter, showing a significantly reduced surface area of microvilli per enterocyte. The reduction in microvillar surface area of animals fed the high-fat diet was accompanied by the decrease in total proteins of the brush border membranes as well as the decrease in the activities of microvillar stalked disaccharidases, i.e., sucrase-isomaltase and lactase. These results provide an evidence that dietary manipulation, even when diets are "complete" in terms of the content of energy, protein, and other micronutrients, can modify the microvillar structure of small intestinal epithelial cells, leading to alterations in the digestive/absorptive surface area of villus cells.

Monostearoylglycerol-starch complex: its digestibility and effects on glycemic and lipogenic responses

We examined whether a modification of a starch into an alpha-amylase resistant form can lead to a reduction of postprandial glucose and insulin responses, and consequently to a change of lipid metabolism in liver and adipose tissue. For this purpose, a processed starch was prepared using a cornstarch (70% amylose and 30% amylopectin) and monoacylglycerol (monostearate; MS), forming monostearate-starch complex (MS-treated cornstarch). When we determined in vitro hydrolysis of MS-treated cornstarch using alpha-amylase and intestinal microvillar alpha-glucosidases, the glucose production rate of the MS-treated cornstarch was slower than the non-treated cornstarch. Measurement of a transmural potential difference (delta PD) evoked by the MS-treated cornstarch in everted rat jejunum showed that the absorption rate of glucose released from the MS-treated cornstarch was also remarkably slower than that from the non-treated cornstarch. The postprandial plasma insulin response to the MS-treated cornstarch was reduced, although plasma glucose response was unchanged. In a feeding study, two groups of five or six male Wistar-strain rats were fed defined diets containing 61.1% MS-treated cornstarch or 58.2% non-treated cornstarch ad libitum for 14 days. Food intakes during the period were similar between the two groups. Feeding the MS-treated cornstarch resulted in a significantly lower maltase activity in upper jejunum than did the non-treated cornstarch feeding. The activities of lipogenic enzymes--fatty acid synthetase (FAS), malic enzyme (ME), and glucose-6-phosphate dehydrogenase (G-6-PDH)--significantly decreased in epididymal adipose tissue of rats fed the MS-treated cornstarch. In the liver, FAS activity was lower in the MS-treated cornstarch group. The results indicated that MS-treated cornstarch was digested less rapidly, and lowered blood insulin response, consequently leading to a declined lipogenesis of adipose tissue and liver. This study suggests that the rate of intestinal hydrolysis of starch is an important determinant of metabolic responses such as glycemic and lipogenic responses to diets.

Maltitol-induced increase of transepithelial transport of calcium in rat small intestine

To gain an insight into a mechanism whereby maltitol increases intestinal absorption of calcium, we evaluated transepithelial calcium transport of everted segments of rat small intestine by comparing the values in the presence of maltitol with the values in the presence of maltose. In jejunal segments, no significant difference in the rate of calcium transport was seen between the incubations in the medium containing 100 mM maltitol and in the medium containing 100 mM maltose, regardless of the calcium concentrations in the mucosal-side medium. By contrast, the everted ileal segments incubated in the presence of maltitol exhibited two-fold greater transepithelial calcium transport than did the segments incubated in the presence of maltose at a high (10 mM) concentration of calcium, whereas at a low (0.5 mM) concentration of calcium, maltitol did not produce a significant effect. With the conditions in which intestinal alpha-glucosidases were inhibited using the medium containing Tris or acarbose, a slight (40%) but significant increase of calcium transport was again observed in the segments incubated in the medium containing maltitol as compared with the medium containing maltose. The results suggest that maltitol enhances the rate of transepithelial calcium transport in the lower part of small intestine by modulating the passive diffusion of calcium, and that not only the nature of low digestibility, but also some other nature(s) of maltitol might be responsible for the maltitol-induced increase of ileal calcium transport.

Immunoelectron microscopic localization of lactase-phlorizin hydrolase in rat small intestine

To provide insight into the intracellular translocation of lactase-phlorizin hydrolase, an immunoelectron microscopy was performed on rapidly embedded Lowicryl K4M sections of rat jejunum. Lactase-phlorizin hydrolase immunoreactivity was detected not only in the microvillous membranes and in the smooth apical vesicles, but also in the lateral membranes, suggesting an alternative route for intracellular transport of lactase-phlorizin hydrolase via the lateral membranes to the microvilli.

Dietary vitamin A modulates lecithin-retinol acyltransferase activity in developing chick intestine

Retinol absorbed and generated from beta-carotene requires to be esterified by lecithin-retinol acyltransferase (LRAT) in intestinal absorptive cells. To characterize developmental changes in retinol absorptive capability in intestine, we determined LRAT activity and the amount of its retinol donor, cellular retinol-binding protein, type two (CRBP(II)) in the duodenum of developing chicks. The LRAT activity in duodenal microsomes was very low at 18- and 20-day chick embryo, but exhibited a rapid (15-fold) increase during 48 h around hatching, which occurred in parallel with the abrupt elevation of the content of CRBP(II) in chick duodenum. To examine whether dietary vitamin A affects the developmental change in LRAT activity and CRBP(II) content, 1-day-old chicks were pair-fed vitamin A-depleted or vitamin A-supplemented diet for 14 days. The chicks fed vitamin A-depleted diet showed significantly reduced LRAT activity and CRBP(II) in duodenum as early as 3 days after the start of the vitamin A-depleted diet. Changing the diet from vitamin A-depleted to vitamin A-supplemented diet led to an increase in duodenal LRAT activity within 24 h, while serum retinol concentration remained unchanged. These results suggest that duodenal LRAT activity and CRBP(II) are modulated by dietary vitamin A during the perinatal period.

Feeding medium-chain triglycerides to rats decreases degradation of sucrase-isomaltase complex in the jejunum

We demonstrated previously that feeding a diet containing medium-chain triglycerides (MCT) to rats causes an increase in the sucrase activity in jejunum relative to diets containing long-chain triglycerides (LCT). To explore the mechanism whereby MCT affect jejunal sucrase activity, 7-wk-old rats were fed a high LCT diet for 7 d, and then they were force-fed either the high LCT diet, a high MCT diet or a high carbohydrate (alpha-methylglucoside) diet for the subsequent 12 h. Feeding the high carbohydrate diet produced significantly greater sucrase and isomaltase activities in both upper and lower jejunum than feeding the LCT diet. Feeding the high MCT diet led to significantly greater sucrase activity in the lower jejunum, but isomaltase activity was not elevated. Rocket immunoelectrophoresis revealed that in the lower jejunum of the rats fed the high MCT diet the proportion of sucrase-isomaltase complex to its degradation product (i.e., isomaltase monomer) was elevated, suggesting that dietary MCT affects sucrase activity by retardation of degradation of sucrase-isomaltase. Because the amounts of total bile acids in the upper jejunum were 50% lower in rats fed the high MCT diet relative to animals fed the high LCT diet, it is likely that MCT feeding decreases secretion of bile into the lumen, which in turn decreases degradation of the sucrase subunit of the sucrase-isomaltase complex.

Immunoelectron microscopic localization of sucrase-isomaltase in rat small intestine

The localization of rat small intestinal microvillous sucrase-isomaltase was studied by immunoelectron microscopy to investigate its intracellular transport to the microvillous membrane. At the same time, the usefulness of a rapid embedding method of tissues in Lowicryl K4M for immunocytochemistry of sucrase-isomaltase was examined. Sucrase-isomaltase was present not only in the microvillous membrane, but also in the apical vesicles and the apical plasma membrane invaginations. Negligible labeling was observed in the other portions of the absorptive cells. These findings suggest that the final step of intracellular transport of sucrase-isomaltase to the microvillous membrane is via smooth apical vesicles. The rapid immunoelectron microscopic method adopted in this study seemed to be a useful technique for the study of the intracellular localization of sucrase-isomaltase.

Adaptive changes of intestinal cellular retinol-binding protein, type II following jejunum-bypass operation in the rat

To examine whether the amount of intestinal cellular retinol-binding protein, type II (CRBP(II)) exhibits an adaptive change in a shortened jejunum, the distal end of 5-cm proximal-jejunal segment of 2-mth-old rats was joined to the proximal end of the ileum by an end-to-end anastomosis (jejunum-bypass operation). Three weeks after the operation, the amounts of CRBP(II) in proximal jejunum, proximal ileum and distal ileum were determined using a monospecific antiserum by enzyme-linked immunosorbent assay. The jejunum-bypass operation led to a 2-fold increase in the total amounts of CRBP(II) in proximal ileum where hyperplasia occurred; this elevation was in parallel to the increase of total proteins and DNA contents. in the proximal jejunum preceding the bypassed segment, the CRBP(II) level per unit DNA increased by 80%. The jejunum-bypass operation changed neither hepatic total retinol content, nor serum concentrations of retinol and retinol binding protein as compared with the sham-operation, suggesting that retinol absorption was elevated in the shortened small intestine. These results suggest that the increase in CRBP(II) content following jejunum-bypass might be an adaptive response to an enhancement of retinol absorption.

Induction and distribution of cellular retinol-binding protein, type two during villus-crypt development in the chick duodenum

Between day 18 of embryogenesis and 1 day posthatch, a rapid and remarkable (over 10-fold) increase in cellular retinol-binding protein, type two (CRBP(II)) levels occurred in the lower portion of duodenal villi of the chick. With further postnatal growth and concomitant with initiation of food intake, CRBP(II) levels increased over 2-fold in the mid-villus enterocytes. The results suggest that a first induction of CRBP(II) occurs in differentiating lower villus enterocytes during the perinatal period and is followed by marked increases in mid-villus cells. These quantitative change in the distribution and levels of CRBP(II) are probably related to the appearance of retinol in the duodenal lumen.

Molecular cloning and sequence analysis of guinea-pig NADPH-cytochrome P-450 oxidoreductase [corrected]

A cDNA clone coding for cytochrome P-450 oxidoreductase was isolated from a guinea-pig liver cDNA library. The cDNA, MSr2, contained a complete coding region of 678 amino acids. The amino acid sequence of the guinea-pig cytochrome P-450 oxidoreductase showed approx. 90% identities with those of rat, human, rabbit, pig enzymes indicating conservation of primary structure of the enzyme during evolutionary divergence of species. The high conservation of acidic residues of the enzyme sustained the importance of them to maintain its function [corrected].

Decrease of lactase activity in the small intestine of jejunum-bypassed rats

The effect of jejunum-bypass operation on lactase in rat small intestine was examined. Three groups of four or five rats were designated as jejunum-bypassed, sham-operated and normal rats. All animals including normal rats received by pair-feeding 5% glucose/1% NaCl for 5 days following the operation; thereafter they were fed ad libitum the laboratory chow diet. Three weeks after the jejunal bypass operation, the proximal ileum exhibited a hyperplasia as evidenced by a concomitant increase in mucosal contents of both total proteins and DNA. The specific activity of lactase in this segment was significantly lower in the operated rats than sham-operated controls, whereas the specific activity of sucrase in this segment was significantly elevated. The reduction of lactase activity was also evident in the proximal jejunal segment as well as in the distal jejunum which was deprived of luminal nutrition, suggesting that some hormonal factor(s) might be involved in the decrease of lactase activity in jejunum-bypassed animals. Electroimmunoassay revealed that the amount of immunoreactive lactase also declined in the operated rats relative to the sham-operated controls. Our results thus suggest that lactase activity in residual ileum is not only unable to compensate for the loss of digestive-absorptive surface of jejunum, but lactase activity even decreases following jejunum-bypass operation.

[Repair of two cases of partial anomalous pulmonary venous return by draining total right pulmonary venous blood to the left atrium through dilated atrial septal defect]

Two cases of partial anomalous pulmonary venous return were reported in whom right pulmonary veins were totally drained to the coronary sinus and to the right atrium respectively. Re-routing of pulmonary veins was done by dilated atrial septal defect and making intra-atrial tunnel using equine pericardial patch. Postoperative courses were uneventful. MRI was useful to identify the pathway from right pulmonary veins to the left atrium.

Effect of maltitol intake on intestinal calcium absorption in the rat

To examine whether sugar alcohol affects intestinal calcium absorption, 5-week-old male Wistar rats were fed a basal diet (66% starch) or the diets containing either 10% maltitol, 10% sorbitol or 10% lactose. At 2 and 6 weeks after the start of feeding, the animals were subjected to 5-day-period calcium balance study. Feeding maltitol diets as well as sorbitol diet led to a significantly elevated intestinal calcium absorption and calcium retention. Lactose diet did not produce an increased intestinal calcium absorption in the condition used in the present study. To explore whether maltitol can exert its effect in a short period of time, the rats were starved for 16h and were fed by a polyethylene tube the diet containing 0.44% calcium together with either 10% maltitol or 10% glucose. The total calcium remaining in the gastrointestinal tract at 6h after feeding was significantly decreased in the rats given maltitol diet as compared to the rats given glucose diet. When 10 microCi of 45CaCl2 was given orally with the diets containing maltitol or glucose, the amount of 45Ca remaining in the gastrointestinal tract at 6h after its administration was smaller in the rats fed maltitol diet than in the rats fed glucose diet. These results suggest that both di- and monosaccharide alcohols might affect intestinal epithelium, resulting in an enhanced intestinal calcium absorption.

[Effect of aortic valve replacement on left ventricular function in adult patients with aortic stenosis]

Echocardiographic and hemodynamic studies were obtained in 16 consecutive adult patients who underwent aortic valve replacement (AVR) with St. Jude Medical valve for aortic stenosis (AS). Three cases of congenital AS was included and two of them had undergone aortic valvotomy in childhood. One of 16 patients died due to late cardiac tamponade six weeks after AVR. Postoperative studies showed improved left ventricular (LV) functions. LV end diastolic and end systolic diameter (LVDs and LVDs) fell from 50.3 and 38.2 to 44.6 and 31.6 mm respectively (p less than 0.05). Fractional shortening (%FS) rose from 26.5 to 32.2% (p less than 0.05). End systolic wall stress (ESWS) fell from 126.2 to 69.6 k dynes/cm2 (p less than 0.01). Cardiac index and pulmonary arterial wedge pressure improved from 3.4 and 14.4 to 3.6 l/min/m2 and 10.5 mmHg respectively (ns). Preoperatively, six were functional class II, eight were class III and one was class IV (New York Heart Association classification). Postoperative improvement was as follows, eight: class I, seven: class II. In four cases, preoperative echocardiography revealed most depressed LV function in %FS (smaller than 21%) and ESWS (greater than 140). Postoperatively they improved from 18.3 and 164 to 26.0% and 72.8 k dynes/cm2 respectively. These results suggested that depressed LV function in the patients with longstanding AS was largely related to limited preload reserve due to LV enlargement and mechanical unloading of LV (correction of afterload mismatch) resulted in improvement of LV function. In conclusion, LV dysfunction owing to AS alone is reversible and AVR results in great clinical improvement.

Dietary-induced increases of disaccharidase activities in rat jejunum

A study was carried out to examine whether the responsiveness of small intestinal epithelial cells to dietary carbohydrate varied during the daily 24 h cycle. The effect of sucrose on disaccharidase activities was compared during a period of decreasing disaccharidase activities, i.e. between 22.00 and 10.00 hours, and increasing disaccharidase activities, i.e. between 10.00 and 22.00 hours, in the jejunum of 7-week-old-rats. Rats were fed on a low-starch, high-fat diet (Lst; starch 5 and fat 73% of gross energy), or a high-starch, low-fat diet (Hst; starch 70 and fat 7% of gross energy). Both dietary groups exhibited typical diurnal variations in jejunal sucrase (EC 3.2.1.48), maltase (EC 3.2.1.20) and lactase (EC 3.2.1.23) activities, exhibiting a peak around 22.00 hours and a trough at approximately 10.00 hours. When rats were fed on diet Lst for 7 d and then force-fed on an isoenergetic sucrose diet (S; sucrose 40 and fat 37% of gross energy) for 6 or 12 h they exhibited increased sucrase, maltase and lactase activities compared with rats fed on diet Lst. The absolute increase in disaccharidase activities was similar regardless of the time diet S was given or whether rats were killed at 10.00 hours or at 22.00 hours. Analyses of sucrase and lactase activities along the villus-crypt columns showed that the distribution of cell cohorts that responded to diet S was not influenced by the time of introduction of diet S. These findings suggest that small intestinal epithelial cells possess the ability to respond to dietary carbohydrate throughout the daily 24 h cycle.

Changes in vitamin A status following prolonged immobilization (simulated weightlessness)

A study was conducted to investigate the effects of a simulated weightlessness induced by chronic immobilization on vitamin A status. To simulate the stress condition of weightlessness, rats were suspended for 10 days in a special jacket to which metal chains were attached. Animals received a commercial stock diet. Control rats were pair-fed in reference to the suspended rats. As compared with the control, prolonged immobilization resulted in a decrease in body weight gain and an increase in adrenal weight occurred. In the suspended rats, serum concentrations of retinol and retinol-binding protein (RBP) declined. Hepatic retinyl palmitate content increased, and the hepatic retinol level was decreased. The prolonged immobilization led to significantly reduced retinyl palmitate levels in the testis and lung as well as lowered testicular retinol levels. The results suggest that the stress state induced by prolonged immobilization caused accumulation of hepatic retinyl palmitate, decreasing the serum retinol concentration and retinyl ester content in the extrahepatic tissues.

Changes in hepatic metabolism through simulated weightlessness: decrease of glycogen and increase of lipids following prolonged immobilization in the rat

The effect of simulated weightlessness on hepatic metabolisms of carbohydrates and lipids was investigated in rats that were chronically immobilized by means of a suspension harness. During the 10-day period of the suspension, the animals showed a substantial decrease in the hepatic glycogen content, whereas the content of hepatic total lipids was markedly elevated. Similar results were obtained when the "suspended" animals were provided with a regular amount of nutrients by a force-feeding procedure. In the suspended animals, hepatic parenchymal cells were filled with large fat droplets, and hepatic triglyceride contents were elevated. The prolonged immobilization led to a slight, but significant, increase in glucose-6-phosphatase activity in the liver, suggesting that an increased glycogen breakdown might have occurred in the suspended animals. However, it was unlikely that the increased amount of glucose produced by the glycogen breakdown was utilized as a substrate for the lipogenesis in the liver, because hepatic lipogenic enzyme activities were unaffected by the suspension. The results suggest that the hepatic lipids accumulate in animals exposed to a prolonged immobilization state, presumably due to a decreased lipolysis and/or a suppressed lipoprotein mobilization from the liver into the blood stream.

Effects of various dietary protein contents on vitamin A status of rats exposed to prolonged immobilization through suspension

The investigation was carried out to clarify the effects of various dietary protein contents on vitamin A status of rats exposed to prolonged immobilization through suspension. A rat wearing a special jacket to which metal chains were attached, was suspended for 10 days as an analogy of simulated weightlessness. Five groups of suspended rats were fed on the diets containing various amounts of casein (5, 10, 20, 40 and 60, w/w%), while control group received the 20% casein diet. Through suspending animals, a decrease in body weight gain and increase in adrenal weights occurred. Serum albumin concentration of the suspended rats fed on the 10, 20, 40 and 60% diets were the same as that of the control rats. The suspended rats showed lowered serum retinol concentrations and elevated hepatic retinyl palmitate contents without noticeable differences between the diets. The hepatic retinol levels were not clearly affected. In the suspended rats, testicular levels of retinyl palmitate and retinol significantly decreased as compared with the control. These parameters' alterations did not relate to serum albumin concentration and were independent of dietary protein levels. The results suggest that stress state may cause suppression of releasing hepatic vitamin A, resulting in a lowered serum retinol concentration, being independent of nutritional status of protein.

Degradation of sucrase-isomaltase in the ileum of jejunum-bypassed rats

At 3 weeks after jejunal-bypass operation in the rat, the proximal ileum exhibited a greater sucrase specific activity than did sham-operated controls, whereas isomaltase activity was unaffected. Electroimmunoassay of sucrase-isomaltase and a degradation product, isomaltase monomer, revealed an elevated molar ratio of sucrase subunit to isomaltase subunit in operated rats, suggesting a decrease in the extent of degradation of ileal sucrase-isomaltase after the jejunal-bypass operation.

Apparent response of subacute sclerosing panencephalitis to intrathecal interferon alpha

An 8-year-old boy with subacute sclerosing panencephalitis (SSPE) was treated with 1.0 to 3.0 x 10(6) IU human interferon alpha (IFN) by the intrathecal route weekly or fortnightly. Pronounced improvement of clinical and electroencephalographic findings were observed in a dose-dependent manner. Our patient raises hope that IFN can induce sustained remission in patients with SSPE.

Gastric acidity-dependent bioavailability of commercial sustained release preparations of indomethacin, evaluated by gastric acidity-controlled beagle dogs

The relationship between gastric acidity and the bioavailability of two kinds of sustained-release indomethacin (IM) formulations was investigated in gastric acidity-controlled beagle dogs, and compared with that of rapid-release IM formulations. All test dosage forms were more rapidly dissolved in simulated intestinal fluid than in simulated gastric fluid. Gastric acidity did not affect the bioavailability of IM from the rapid-release formulation. However, the bioavailability of IM from the two kinds of sustained-release formulations were markedly influenced by gastric acidity. The rates of IM bioavailability from both of the sustained-release formulations were faster under low acidity conditions than under high acidity conditions (p less than 0.01). In addition, Tmax and mean residence time (MRT) were approximately the same for the rapid-release and sustained-release formulations under low acidity conditions. These results suggest that the IM sustained-release formulations showed a rapid-release profile under low acidity conditions.

Effects of medium-chain triglycerides on brush border membrane-bound enzyme activity in rat small intestine

The effects of various types of dietary fat on brush border membrane-bound enzymes in rat intestinal mucosa were examined. Four groups of five rats were pair-fed defined diets for 10 d. The control group was fed a diet containing 57% sucrose and 2% corn oil as a fixed carbohydrate reference; the three experimental groups received diets containing 57% sucrose and 2% corn oil plus 13% fat in the form of medium-chain triglycerides (MCT) or long-chain triglycerides (LCT) (either lard as a highly saturated fat or corn oil as a highly unsaturated fat). Feeding LCT compared to the control diet, decreased sucrase activity in mucosal brush borders of the duodenum and jejunum. In these segments of MCT-fed rats, sucrase activity was similar to that in the control animals. In another experiment, measuring immunoreactive sucrase-isomaltase in jejunal brush border membranes revealed that feeding a high corn oil diet, but not a high MCT diet, led to a reduction in the sucrase catalytic activity per unit weight of enzyme protein, suggesting that the degradation status of sucrase-isomaltase might be altered by the different types of dietary fats. With MCT feeding, jejunal alkaline phosphatase activity was enhanced to a large extent compared to the activity in other groups. Feeding MCT, compared to lard or corn oil, also increased microvillus phospholipids of the jejunal mucosa. These results suggest that MCT, unlike LCT, do not suppress the activity of mucosal microvillus membrane enzymes in rat small intestine.

Age-related changes in sucrase and lactase activity in the small intestine of 3- and 10-week-old obese mice (C57BL/6Jobob)

The relationship between obesity and the digestion of carbohydrates is poorly understood. Data in humans have provided conflicting results. Studies using the obese mouse (C57BL/6Jobob) suggest that obesity is associated with increased activity of intestinal alpha-disaccharidases. To evaluate the developmental pattern of these enzyme activities in obesity, we determined the activity of sucrase and lactase in the small intestine of genetically obese mice (C57BL/6Jobob) and lean littermates at 3 and 10 weeks of age. Sucrase and lactase activities were measured on intestinal homogenates from segments of the small intestine in mice maintained on standard laboratory diets during the postweaning period. Results were expressed as specific activity and total activity per intestinal segment. Obese mice did not differ from lean littermates in body weight at 3 weeks of age, but exhibited increased protein content in the proximal small intestine. Sucrase specific activity was significantly higher in the obese mice at 3 weeks of age in all intestinal segments. Sucrase total activity showed a similar pattern. At 10 weeks of age, body weights of obese mice were substantially greater than the lean littermates. Sucrase specific and total activities were also greater in the obese mice at 10 weeks of age. Lactase specific activity, however, was similar in both obese and lean mice at both ages studied. Lactase total activity was greater in the obese mice, consistent with their greater intestinal mass. These observations demonstrate that changes in the intestinal sucrase activity of the obese mouse precede the development of excessive body weight.

[Application of gastric acidity-controlled beagle dog to bioavailability study of cinnarizine]

The relationship between gastric acidity and bioavailability of a weakly basic drug, cinnarizine (CN) was investigated in the gastric acidity-controlled beagle dogs. The dissolution of CN from capsules was very fast at pH 1.2 but it decreased with an increase in pH. The capsules containing CN were orally administered to the beagle dogs of the following three groups: 1) the dogs whose gastric acidity were not controlled; 2) the dogs whose gastric acidity were controlled to high levels (less than pH 2) with pentagastrin; 3) the dogs whose gastric acidity were controlled to low levels (more than pH 6) with omeprazole. The peak plasma concentration (Cmax) and the area under the plasma concentration-time curve (AUC0-8h) of CN were most variable in the first group. On the other hand, the variations of these parameters were small in the second and third groups. The Cmax and AUC0-8h of CN in the high acidity group were about 20 times larger than those in the low acidity group (p less than 0.01). The bioavailability of CN was markedly influenced by the gastric acidity. This finding was similar to that in human subjects. The gastric acidity-controlled beagle dogs are useful animal models to evaluate the bioavailability of weakly basic drugs such as CN, exhibiting pH-dependent dissolution behavior.

Developmental changes in vitamin A level and lack of retinyl palmitate in chick lungs

1. Developmental changes in retinol and retinyl palmitate contents in lungs of chick embryos and posthatch chicks were investigated. 2. Remarkable changes in the lung retinol levels were found during development of chicks. Embryonic lungs 5 days prior to hatching contained the highest content of retinol. The level then declined rapidly and was lowest on 1 day before hatching. 3. Its level then rose substantially within 7 days after hatching. 4. No retinyl palmitate in chick lungs was detectable at any of the developmental stages examined, nor even in adult hen. 5. Serum retinol level changed in parallel with the lung retinol. 6. The patterns of changes in liver retinol and retinyl palmitate were remarkably different from that occurring in the lung retinol. In chick embryonic livers, the levels of them were low, followed by a rapid increase after hatching. 7. The high level and its rapid decrease of lung retinol content during development of chick embryos may be functionally connected with retinol action in embryonic lungs for cellular differentiation and maturation.