Characteristics of perceived parenting styles in Japan using the EMBU scale

OBJECTIVE

The EMBU (Egna Minnen av Barndoms Uppfostran) is a self-report questionnaire for the assessment of one's memory of parental rearing experiences. We are interested in using this scale to determine the characteristics of perceived parenting styles in Japan.

METHOD

The study subjects consisted of 1320 healthy Japanese volunteers, comprising 687 males (52%) and 633 females (48%). We investigated the relationship between demographics and the EMBU scale.

RESULTS

ANCOVA revealed that the subject's gender had a significant effect on paternal rejection scores (male > female), and both gender and birth-order position had significant effects on emotional warmth scores for both parents (female > male, and only-child > middle or last-born child). Birth-order position had significant effects on maternal over-protection, with the highest score being that of only children, and on the aspect of favouritism (favouring subjects), scores for both parents were highest from the last-born children. Rejection scores for the mother were significantly higher than those for the father from female subjects. Among both male and female subjects, emotional warmth scores and overprotection scores for the mother were significantly higher than those for the father. Among male subjects, scores for the mother on favouritism of the subject were significantly higher than those for the father. On the other hand, among female subjects, scores for the father on favouritism of the subject were higher than scores for the mother.

CONCLUSION

Our results suggest that parenting styles have significant interrelationships with the gender and birth-order position of the subject.

Morphological relationship between serotonergic neurons and nitrergic neurons for electrolytes secretion in the submucous plexus of the guinea pig distal colon

In the submucous plexus, double immunocytochemistry revealed that nitric oxide synthase (NOS)-immunoreactivity was found in both numerous nerve fibers and some nerve cell bodies, while 5-hydroxytryptamine (5-HT)-immunoreactivity was limited to many nerve fibers, but not any nerve cell bodies. About 30% of the total NOS positive neurons (978) had close or some contact with 5-HT positive nerve fiber, suggesting that NO may participate in the 5-HT-evoked chloride secretion.

Autolysosomal membrane-associated betaine homocysteine methyltransferase. Limited degradation fragment of a sequestered cytosolic enzyme monitoring autophagy

We compared the membrane proteins of autolysosomes isolated from leupeptin-administered rat liver with those of lysosomes. In addition to many polypeptides common to the two membranes, the autolysosomal membranes were found to be more enriched in endoplasmic reticulum lumenal proteins (protein-disulfide isomerase, calreticulin, ER60, BiP) and endosome/Golgi markers (cation-independent mannose 6-phosphate receptor, transferrin receptor, Golgi 58-kDa protein) than lysosomal membranes. The autolysosomal membrane proteins include three polypeptides (44, 35, and 32 kDa) whose amino-terminal sequences have not yet been reported. Combining immunoblotting and reverse transcriptase-polymerase chain reaction analyses, we identified the 44-kDa peptide as the intact subunit of betaine homocysteine methyltransferase and the 35- and 32-kDa peptides as two proteolytic fragments. Pronase digestion of autolysosomes revealed that the 44-kDa and 32-kDa peptides are present in the lumen, whereas the 35-kDa peptide is not. In primary hepatocyte cultures, the starvation-induced accumulation of the 32-kDa peptide occurs in the presence of E64d, showing that the 32-kDa peptide is formed from the sequestered 44-kDa peptide during autophagy. The accumulation is induced by rapamycin but completely inhibited by wortmannin, 3-methyladenine, and bafilomycin. Thus, detection of the 32-kDa peptide by immunoblotting can be used as a streamlined assay for monitoring autophagy.

Identification of autolysosomes directly associated with proteolysis on the density gradients in isolated rat hepatocytes

Autophagy-related vacuoles, i.e., autophagosomes (AVi), autolysosomes (AVd) and dense bodies (DB), are intracellular organelles within which macroautophagy and bulk proteolysis set out and progress. Separation of these particles in freshly isolated rat hepatocytes, monitored by beta-hexosaminidase, a lysosomal marker enzyme, was established by density gradient centrifugation. Percoll density gradients were modified and improved by adding free polyvinylpyrrolidone (PVP, 0.75%) to 60% Percoll, which made it possible to separate AVd (buoyant peak, d = 1.090) and DB (dense peak, d = 1.131) effectively. Addition of graded levels of a regulatory amino acid mixture (Reg AA) to hepatocyte incubation not only suppressed proteolysis, but also lead to a shift of vacuolar profiles on the density gradients from the buoyant to the dense region. Alterations in the vacuolar shift and proteolysis were highly proportional over a full range of regulation by Reg AA. Morphometric analysis of autophagic vacuoles by electron microscopy revealed changes in the aggregate volumes of both AVi and AVd by Reg AA, which enabled us to estimate autophagic subpopulation of the buoyant peak on the gradient profile. All the results demonstrate that AVd shifts on the density gradients in proportion to alterations in proteolysis regulated by amino acids, and thus the gradient profile can be used as a measure of macroautophagy; and in addition that AVd actively involved in proteolysis occupies only a part of the buoyant peak on the gradients.

5-HT activates nitric oxide-generating neurons to stimulate chloride secretion in guinea pig distal colon

The participation of nitric oxide (NO) in serotonin (5-hydroxytryptamine; 5-HT)-evoked chloride secretion in guinea pig distal colon was examined. Submucosal/mucosal segments were mounted in Ussing flux chambers, and an increase in short-circuit current (Isc) was used as an index of secretion. Addition of 5-HT to the serosal side produced a concentration-dependent (10(-7)-10(-5) M) increase in Isc caused by chloride secretion. NG-nitro-L-arginine (L-NNA) significantly reduced the 5-HT-evoked early (P-1) and late (P-2) responses to 61.1 and 70.6% of control, respectively. Neurally evoked response was also inhibited by L-NNA. The NO donor sodium nitroprusside (SNP, 10(-4) M) increased basal Isc mainly because of chloride secretion. The SNP-evoked response was significantly reduced by tetrodotoxin but was unchanged by atropine or indomethacin. These results suggest that the 5-HT-evoked increase in Isc is associated with an NO-generating mechanism. Atropine significantly reduced the 5-HT (10(-5) M)-evoked P-1 and P-2 responses to 71.8 and 19.7% of control, respectively. Simultaneous application of atropine and L-NNA further decreased the 5-HT-evoked responses more than either drug alone; application of L-NNA and atropine decreased the 5-HT-evoked P-1 and P-2 responses to 68.5 and 39.2% of atropine-treated tissues, respectively. These results suggest that noncholinergic components of P-1 and P-2 responses are 71.8 and 19.7% of control, respectively, and that NO components of P-1 and P-2 responses are 32 and 61%, respectively, of the noncholinergic component of the 5-HT-evoked responses. The results provide evidence that NO may participate as a noncholinergic mediator of 5-HT-evoked chloride secretion in guinea pig distal colon.

Combined blockade of 5-HT3- and 5-HT4-serotonin receptors inhibits colonic functions in conscious rats and mice

We have already reported that 5-hydroxytryptamine3 (5-HT3) receptor antagonists failed to modify 5-HT-accelerated colonic transit in conscious rats, but the 5-HT3 and 5-HT4 receptor dual antagonist FK1052 prevented the enhancement. In this study, the inhibitory effect on the stimulated colonic transit was not also observed with 5-HT4 receptor antagonists (SDZ205-557 and SB204070) in freely moving rats with chronic cannulas implanted into the proximal colon. In contrast, combined antagonism by simultaneous administration of ondansetron and the 5-HT4 receptor antagonist exerted a drastic inhibitory effect on the propulsive motility. Furthermore, we examined the effect of 5-HT receptor antagonists on 5-HT-induced fluid secretion in mice. Although none of these selective 5-HT receptor antagonists (YM060 and ondansetron as 5-HT3 receptor antagonist, SB204070 as 5-HT4 receptor antagonist) by itself produced a great inhibition of the 5-HT-induced diarrhea, the combination of a 5-HT3 receptor antagonist and a 5-HT4 receptor antagonist markedly reduced the diarrhea. These data suggest that 5-HT-accelerated colonic motility and 5-HT-evoked fluid secretion are mediated by both 5-HT3 and 5-HT4 receptors and that the pathways activated by these receptors may collaborate.

Participation of 5-HT3, 5-HT4, and nicotinic receptors in the peristaltic reflex of guinea pig distal colon

The roles of 5-hydroxytryptamine3 (5-HT3), 5-HT4, and nicotinic receptors in the peristaltic reflex were investigated in isolated segments of guinea pig distal colon. The reflex assessed by measuring the propulsion of solid pellets, was affected neither by 5-HT3-selective antagonists (ondansetron granisetron) nor by 5-HT4-selective antagonists (SDZ-205-557, GR-113808A, SB-204070) applied individually (1.0 microM); nevertheless, the reflex was inhibited by combining these antagonists or by applying a 5-HT3/5-HT4 dual antagonist (FK-1052). Hexamethonium abolished the peristaltic reflex at 100 microM, but not at 10-32 microM. In contrast, the peristaltic reflex was inhibited when hexamethonium (32 microM was combined with either a 5-HT3- or 5-HT4-selective antagonist (1.0 microM). These observations suggest that 5-HT3, 5-HT4, and nicotinic receptors participate in the initiation and/or propagation of the peristaltic reflex. The data are consistent with the idea that these receptors are arranged in parallel in the neural pathways that mediate the peristaltic reflex in the distal colon.

Acute effect of epinephrine on muscle proteolysis in perfused rat hindquarters

An acute and direct effect of epinephrine (Epi) on muscle proteolysis was investigated using a single-pass mode of rat hindquarter perfusion. The rate of tyrosine (Tyr) release at > 30 min with cycloheximide was regarded as the muscle proteolytic rate. Infusion of Epi (500 nM) to the hindquarters of fed rats led to a sharp decrease in the Tyr release to 50% within 5 min, accompanied by an increase in perfusion pressure and edema around the perfused tissues. To clarify the mechanism, alpha- and beta-antagonists were used together with Epi. A mixture of 10 microM prazosin and 10 microM yohimbine (alpha-adrenergic blockade) before or after Epi infusion completely prevented the edema development and resulted in a new steady state to 80% of the initial rate. On the contrary, 100 microM propranolol (a beta-antagonist) with Epi did not abolish the edema and caused fluctuation in Tyr release. Whether the above results are affected by changes in Tyr transport at the plasma membrane was tested by measuring Tyr efflux from the perfused muscle. Only a beta-adrenergic blockade significantly reduced the rate constant of Tyr efflux from the intracellular pool by 13%. These results suggested that the suppression of Tyr release by alpha-adrenergic activity was mainly due to the effect on Tyr efflux, whereas that by beta-adrenergic activity was not at the Tyr transport level but at the proteolysis level, demonstrating that Epi directly inhibits proteolysis of skeletal muscle via the beta-adrenoceptor.

In situ identification of messenger RNA of endothelial type nitric oxide synthase in rat cardiac myocytes

The endothelial type nitric oxide synthase (NOS) termed as NOS-III has been demonstrated in various nonendothelial cells. Although NOS-III was recently found in the cardiac tissues, identification of the cells expressing NOS-III gene in the heart remains unknown. In this study, we compared the expression of NOS-III mRNA in various tissues of rats by Northern blot analysis using a homologous cDNA probe and identified the cell type by in situ hybridization histochemistry with a cRNA probe. NOS-III mRNA was found more abundantly in atria and ventricle than in other various tissues examined. NOS-III mRNA was intensely and specifically visualized in the cardiac myocytes as well as in the endothelial cells of the heart. No staining was seen with a sense cRNA probe. These results provide the first in vivo evidence for NOS-III mRNA in the cardiac myocytes and suggest its role in the regulation of cardiac functions.

Is nitric oxide involved in 5-HT-induced fluid secretion in the gut?

The present study was undertaken to test the hypothesis that 5-HT stimulates nitric oxide (NO) generating neurons, and that these neurons participate in the mediation of 5-HT-induced fluid secretion. 5-HT induced electrogenic Cl- secretion in guinea-pig distal colon. This response was abolished by tetrodotoxin but not by atropine. The maximum response to 5-HT (10(-5) M) was inhibited by approximately 65% (P < 0.05, n = 6) by the NO synthase inhibitor, NG-nitro-L-arginine (L-NNA, 10(-4) M). The substrate of NO synthase, L-Arg (10(-3) M) reversed the inhibition of 5-HT-induced secretions by L-NNA. 5-HT-induced diarrhea in fasted mice was reduced by atropine in vivo. NG-Nitro-L-Arg methyl ester (L-NAME, 1-32 mg/kg, i.p.) dose-dependently inhibited 5-HT (1 mg/kg)-induced diarrhea. The inhibitory effect of L-NAME was reversed by L-Arg, but not D-Arg (600 mg/kg, i.p., respectively). Taken together, these data suggest that 5-HT-induced fluid secretion in the gut is partly due to the activation of neurons that generate NO.

Leucine-specific binding of photoreactive Leu7-MAP to a high molecular weight protein on the plasma membrane of the isolated rat hepatocyte

Leu8-MAP (Multiple Antigen Peptide) is an effective inhibitor of macroautophagy and proteolysis in the isolated rat hepatocyte, having an apparent Km (0.1 mM) equaling leucine. Since it is not transported into the cytosolic compartment, it very likely mediates its effect through a plasma membrane site. In an attempt to identify the site we photoreacted intact cells with a biologically active, iodinatable azide derivative of Leu7-MAP. A approximately 340,000 M(r) protein whose labeling was protected 83% with 20 mM Leu was found in plasma membrane fractions when electrophoresed in 7.5-20% gradient gels under nonreducing conditions; addition of 20 mM dithiothreitol generated smaller m.w. products, possibly subunits, of consistent size. No specific labeling was observed with photoreactive derivatives of Ile7-MAP or Val7-MAP.

De novo autophagic vacuole formation in hepatocytes permeabilized by Staphylococcus aureus alpha-toxin. Inhibition by nonhydrolyzable GTP analogs

The role of GTP-binding proteins in autophagic vacuole formation was investigated in isolated rat hepatocytes permeabilized by alpha-toxin from Staphylococcus aureus, an agent which creates stable plasma membrane channels allowing exchange of small (< or = 1000 Da) molecules. Vacuole formation was monitored from the uptake of 125I-tyramine-cellobiitol (125ITC) into osmotically sensitive vacuoles isolated on colloidal silica density gradients. Separation was based on an established observation that autophagic vacuoles are retained in a heavy midgradient band when samples are layered, but are selectively shifted to dense fractions when they are previously dispersed in the gradient material. The vacuolar uptake of 125ITC was concentration-dependent and required exogenous ATP: 94% was directly mediated by sequestration; 6% was acquired by fluid-phase endocytosis as monitored by [carboxyl-14C]dextran-carboxyl. Although the amino acid control of proteolysis was lost, addition of the nonhydrolyzable GTP analog GTP gamma S (as well as GMP-PNP) decreased fractional rates of direct vacuolar 125ITC uptake and long-lived proteolysis by similar amounts (1.02-1.03% h-1), substantiating the notion that the effects were the direct result of autophagic inhibition. These and associated findings, supported by quantitative electron microscopy, indicate the presence of ongoing macro- and microautophagy in alpha-toxin-permeabilized cells and suggest that one or more GTP-binding proteins is required in macroautophagic vacuole formation.

Pharmacological profile of FK480, a novel cholecystokinin type-A receptor antagonist: comparison to loxiglumide

The pharmacological profile of FK480[(S)-(+)-N-<1-(2)-fluorophenyl)-3,4,6,7-tetra hydro-4-oxo-pyrrolo(3,2,1-jk) (1,4)benzodiaze-pine-3-yl>-1H-indole-2- carboxamide], a novel cholecystokinin type-A (CCK-A) receptor antagonist, was compared with that of the CCK-A receptor antagonist, loxiglumide. Both FK480 and loxiglumide inhibited 125I-labeled CCK-8 (125I-CCK-8) binding to rat pancreatic and guinea-pig gallbladder membranes with IC50 values of 0.40 +/- 0.04 and 0.06 +/- 0.02 nM for FK480 and 330 +/- 66 and 66 +/- 10 nM for loxiglumide, respectively. These two agents also inhibited 125I-CCK-8 binding to guinea-pig brain (cerebral cortex) receptors with respective IC50 values of 72 +/- 11 nM and > 10 microM, indicating less affinity to central receptors. Intravenous administration of FK480 (ED50 = 18 micrograms/kg) was 2800 times more potent than that of loxiglumide (ED50 = 50 mg/kg) in inhibiting CCK-8-induced pancreatic amylase secretion in rats. Furthermore, FK480 had ED50 values of 10 and 8.4 micrograms/kg, respectively, in antagonizing CCK-8-induced inhibition of charcoal meal gastric emptying in mice when administered orally 1 or 5 hr before the CCK-8. Loxiglumide (ED50 = 23.5 mg/kg, when administered orally 1 hr before the CCK-8) also antagonized it, but its activity was 2400 times less than that of FK480. We conclude that FK480 is a potent, orally effective CCK-A receptor antagonist with long duration of action.

Multiphasic control of proteolysis by leucine and alanine in the isolated rat hepatocyte

Autophagically mediated proteolysis in the perfused rat liver is under complex multiphasic control by a small group of amino acids dominated by leucine. Because there have been no prior reports of such regulation in the isolated hepatocyte, our goal was to determine whether it is a manifestation of interactions between diverse cells in the intact liver or, alternatively, the expression of a unique control mechanism within a single population of cells. Hepatocytes were isolated from livers of ad libitum-fed rats and incubated with cycloheximide at low density (approximately 10(6) cells/ml) for the determination of valine release. As in perfusion experiments with synchronously fed rats, proteolytic responses to leucine in cells from fed rats were mediated through two inhibitory mechanisms that alternated randomly on a day-to-day basis. The first (L) represented a typical multiphasic dose-response with low- and high-concentration inhibition separated by a sharp zonal loss of inhibition that could be abolished by alanine. The second (H) mediated inhibition only at high concentrations. It disappeared after 24 h of starvation, leaving L as the prevailing mode. The findings indicate that both macroautophagy and the multiphasic mechanism for regulating it coexist in a single population of hepatocytes, making the cells suitable for studies aimed at defining the putative plasma membrane site of leucine recognition.

A decreased number of primordial germ cells and the small numbers and reduced sizes of germinal granules in the periodic albino mutant of Xenopus laevis

Light and electron microscopy were used to examine the cause of the small number of primordial germ cells (PGCs) that were unexpectedly found in periodic albino (a(p)/a(p)) tadpoles of Xenopus laevis. The observations revealed that the volumes of germ plasm were not significantly different between a(p)/a(p) and wild-type eggs and that the germ plasm of ap/ap eggs contained a smaller number of germinal granules than are present in wild-type eggs and the granules were also smaller than in the wild-type eggs. It was concluded that the number of PGCs might be primarily determined by the number and size of germinal granules.

Effect of FK1052, a potent 5-hydroxytryptamine3 and 5-hydroxytryptamine4 receptor dual antagonist, on colonic function in vivo

5-Hydroxytryptamine (5-HT) is an important neurotransmitter and hormone/paracrine agent mediating various enteric functions. Its precise physiological and pathophysiological role remains unclear. This study investigated the effects of 5-HT on colonic function and the effects of the newly developed 5-HT3 and 5-HT4 receptor antagonist, FK1052, on colonic responses to 5-HT or stress stimulus in vivo. In conscious rats, both 5-HT and 5-methoxytryptamine significantly increased fecal pellet output and accelerated colonic transit. In contrast, the effect of 2-methyl-5-HT was slight. Although ondansetron and granisetron slightly reduced 5-HT (1 mg/kg s.c.) stimulated colonic transit, FK1052 [(+)-8,9-dihydro-10-methyl-7-[(5-methyl-4-imidazolyl)methyl]pyrido- [1,2-a]-indole-6(7H)-one hydrochloride], at 0.1 mg/kg p.o., inhibited completely the increases in the colonic transit. Furthermore, FK1052, ondansetron and granisetron significantly depressed the increase in fecal pellet output caused by wrap-restraint stress, with ED50 values of 0.21, 3.0 and 1.1 mg/kg p.o., respectively. Intraperitoneal administration of 5-HT and 5-methoxytryptamine, but not 2-methyl-5-HT, produced a dose-related increase in the incidence of diarrhea in fasted mice. 5-HT (0.32 mg/kg i.p.)-induced diarrhea was also inhibited by FK1052, ondansetron and granisetron, with ED50 values of 0.09, 2.3 and 0.88 mg/kg p.o., respectively. These findings suggest that 5-HT3 and 5-HT4 receptors may have an important role in colonic function and FK1052 may have therapeutic potential in the treatment of gastrointestinal dysfunction such as irritable bowel syndrome.

Pharmacological characterization of FK1052, a dihydropyridoindole derivative, as a new serotonin 3 and 4 dual receptor antagonist

(+)-8,9-Dihydro-10-dihydro-10-methyl-7-[(5-methyl-4-imidazolyl) methyl]pyrido-[1,2-a]indol-6(7H)-one hydrochloride (FK1052) is a newly designed and synthesized 5-hydroxytryptamine (5-HT)3 receptor antagonist with 5-HT4 receptor antagonistic activity. This compound, as well as ondansetron and granisetron, dose-dependently inhibited the von Bezold-Jarish reflex, a 5-HT3 receptor-mediated response, after intravenous (i.v.) and intraduodenal (i.d.) dosing to rats. The ID50 values showed FK1052 (0.28 microgram/kg, i.v., 5.23 micrograms/kg, i.d.) to be more potent than ondansetron (5.23 micrograms/kg, i.v., 170 micrograms/kg, i.d.) and granisetron (0.70 micrograms/kg, i.v., 66 micrograms/kg, i.d.). Furthermore, bioavailabilities of the test drugs by ID50 ratio (i.d./i.v.) showed that FK1052(17) was better absorbed than ondansetron(33) and granisetron(94) and possessed a similar duration of action to that of ondansetron and granisetron. We also examined the effects on 2-methyl-5-HT-, 5-HT- and 5-methoxytryptamine-induced contractions of guinea pig isolated ileum. FK1052, ondansetron and granisetron concentration-dependently inhibited 2-methyl-5-HT, a 5-HT3 agonist-induced contraction. The pA2 values for the 5-HT3 receptor indicated that FK1052 (8.36) was 40 times and three times more potent than ondansetron (6.79) and granisetron (7.86), respectively. FK1052, unlike ondansetron and granisetron, inhibited the 5-HT4-mediated component of concentration-response curve to 5-HT. Furthermore, FK1052 suppressed 5-methoxytryptamine, a 5-HT4 agonist-induced contraction in a concentration-dependent but insurmountable manner.(ABSTRACT TRUNCATED AT 250 WORDS)

Parallel control of hepatic proteolysis by phenylalanine and phenylpyruvate through independent inhibitory sites at the plasma membrane

Intracellular protein degradation in the rat hepatocyte is regulated by 7 amino acids of which Leu, Gln, and Tyr play major roles. Although Phe is known to inhibit proteolysis as effectively as Tyr at high concentrations, it has not been regarded as an active regulator because of its rapid hydroxylation to Tyr. We now show that proteolytic responses to Phe during liver perfusion differ strikingly from effects of the multiphasic regulators Leu, Gln, and Tyr in eliciting mirror image responses at half-normal and normal plasma concentrations. Since response curves to phenylpyruvate and Phe were identical, we considered the possibility that phenylpyruvate mediated its anomalous inhibition intracellularly. However, when phenylpyruvate was produced from phenyllactate intracellularly at a rate providing the same rate of transamination (and intracellular concentration) as that derived from the uptake of phenylpyruvate, no response was obtained. Hence, the effect of phenylpyruvate was not initiated within the cell but more likely from the plasma membrane. Comparable evidence for Phe is less direct. Recent findings indicate that recognition sites for Leu and Gln are located at the plasma membrane. Since Phe augments the concerted inhibition by Leu and Gln at 4-fold normal levels, Phe is probably recognized in close proximity to them. However, the failure of phenylpyruvate to substitute for Phe in this interaction suggests that proteolytic inhibition by phenylpyruvate and Phe is mediated through similar, although independent, plasma membrane sites.

4-Amino-6-methylhept-2-enoic acid: a leucine analogue and potential probe for localizing sites of proteolytic control in the hepatocyte

A recent analysis of leucine analogues has suggested that the carboxyl group is not required for mediating low concentration proteolytic inhibition in liver cells. In designing a probe to localize the regulatory site(s), we tested this hypothesis by synthesizing an analogue with a 2-carbon insert between the carboxyl and alpha-carbon. The Wittig product, a trans olefin, was fully active. Surprisingly, low concentration activity was lost when the double bond was eliminated by hydrogenation although some inhibitory effectiveness at high concentrations was evident. Since the double bond extends the carboxyl group away from the alpha-carbon, the results support the above hypothesis as well as the feasibility of adding functional groups to the carboxyl end of leucine.

Differential regulation of the degradation of myofibrillar and total proteins in skeletal muscle of rats: effects of streptozotocin-induced diabetes, dietary protein and starvation

In order to examine the effects of streptozotocin-induced diabetes, dietary protein, and starvation on protein degradation in skeletal muscle of perfused rat hindquarters, rates of myofibrillar and total protein degradation were estimated from the release of 3-methylhistidine (N tau-methylhistidine, 3-MH) and tyrosine, respectively. In rats fed a 20% protein diet (controls), the fractional degradation rate of myofibrillar protein was approximately 56% of the total muscle protein. In streptozotocin-induced diabetic rats, 3-MH release by perfused muscle increased significantly on d 1 of treatment and sustained a high level thereafter. By contrast, tyrosine release did not change. Feeding a 50% protein diet for 1 wk altered neither 3-MH nor tyrosine release. Protein-free feeding, though, suppressed tyrosine release to 49% of controls, but did not affect 3-MH release. Starvation for 3 d did not affect tyrosine release, but did increase 3-MH release to 203% of controls. These results indicate that in diabetic and starved rats myofibrillar protein is preferentially degraded, while in protein-deficient rats, non-myofibrillar protein degradation is selectively suppressed. From these observations, we conclude that the degradation of myofibrillar and non-myofibrillar proteins in skeletal muscle can be differentially regulated.

A pulsatile pump for cardiopulmonary bypass and its clinical use

A pulsatile pump driven by a coil spring, which was designed and constructed by us, is described in this report. It consists of two main parts, a disposable blood chamber and a driving section. The blood chamber has two leaflet valves and a piston, which is covered with two bellofram rolling diaphragms and moves into the housing to draw in and eject the blood. The driving section consists of three cams, an electric motor and a coil spring. The ejection force is wholly produced by the compressed coil spring and is transmitted to the piston in the blood chamber by a rod. This pump allows the ejection pressure, the beat rates, and the stroke volume all to be changed independently. The performance of the pump was tested by using a circulation model where the beat rate was adjusted from 30 to 250 bpm. The output subsequently increased from 0.8 l/min to 5.7 l/min and the stroke volume, from 20.4 ml to 36.7 ml. This new pump has been used for clinical cardiopulmonary bypasses in 24 patients of open heart surgery and the pressure traces during perfusion resembled those of the patients' own hearts.