Health-Seeking Behaviors in Mozambique: A Mini-Study of Ethnonursing

In settings where traditional medicine is a crucial part of the healthcare system, providing culturally competent healthcare services is vital to improving patient satisfaction and health outcomes. Therefore, this study sought to gain insight into how cultural beliefs influence health-seeking behaviors (HSBs) among Mozambicans. Participant observation and in-depth interviews (IDIs) were undertaken using the ethnonursing method to investigate beliefs and views that Mozambicans (living in Pemba City) often take into account to meet their health needs. Data were analyzed in accordance with Leininger’s ethnonursing guidelines. Twenty-seven IDIs were carried out with 12 informants from the Makonde and Makuwa tribes. The choice of health service was influenced by perceptions of health and illness through a spiritual lens, belief in supernatural forces, dissatisfaction with and dislike of the public medical system on grounds of having received poor-quality treatment, perceived poor communication skills of health professionals, and trust in the indigenous medical system. This study confirmed the need for health professionals to carefully take cultural influences into consideration when providing care for their patients. We recommend an educational intervention that emphasizes communication skills training for healthcare workers to ensure successful physician/nurse–patient relationships.

Can a sleep disorder intervention-embedded self-management programme contribute to improve management of diabetes? A pilot single-arm pretest and post-test study

OBJECTIVE

To investigate the efficacy and feasibility of a self-management programme incorporating a sleep intervention for improving diabetes outcomes.

DESIGN

A single-arm pre-test and post-test study was conducted within a community setting in Hiroshima, Japan.

PARTICIPANTS

Participants were aged 52-74 years and diagnosed with type 2 diabetic nephropathy stages 1-3.

INTERVENTIONS

Participants received self-management education from nurses for 6 months. First, the nurses assessed their sleep conditions using insomnia scales and a sleep metre. Then, the participants learnt self-management to increase their physical activity and improve their sleep condition. They also implemented diet therapy and medication adherence.

OUTCOME MEASURES

Physiological indicators, subjective and objective indicators of sleep quality, self-management indicators, quality of life (QOL) and feasibility were evaluated. To confirm the efficacy of intervention, Freidman tests, analysis of variance, Wilcoxon signed-rank test and t-test were performed. Pearson's correlations were analysed between activities and sleep condition.

RESULTS

Of the 26 enrolled participants, 24 completed the programme and were analysed. Among them, 15 participants (62.5%) had sleep disorders caused by multiple factors, such as an inappropriate lifestyle and physical factors that interfere with good sleep. Although insomnia scales did not change for the sleep disorders, their subjective health status improved. Regarding indicators related to diabetes management, lifestyles improved significantly. Haemoglobin A1c, body mass index, systolic blood pressure, non-high-density lipoprotein-cholesterol and QOL also improved. All participants except one were satisfied with the programme. However, use of the sleep metre and nurses' consultation about sleep disturbance were not well evaluated.

CONCLUSIONS

This programme was effective in improving diabetes status, lifestyle and behaviour changes. However, its effect on sleep condition was limited because of its complexity. A simple and novel approach is needed to strengthen the motivation for sleep behaviour change and to increase programme efficacy and feasibility.

TRIAL REGISTRATION NUMBER

UMIN000025906.

A Health Guidance App to Improve Motivation, Adherence to Lifestyle Changes and Indicators of Metabolic Disturbances among Japanese Civil Servants

We investigated whether an Information and Communication Technology (ICT) application (app) motivated to increase adherence to lifestyle changes, and to improve indicators of metabolic disturbances among Japanese civil servants. A non-randomized, open-label, parallel-group study was conducted with 102 participants aged 20–65 years undergoing a health check during 2016–2017, having overweight and/or elevated glucose concentration. Among them, 63 participants chose Specific Health Guidance (SHG) and ongoing support incorporating the use of an app (ICT group) and 39 individuals chose only SHG (control group). Fifty from the ICT group and 38 from the control group completed the study. After completing the 6-month program, the control group showed a significant decrease in body mass index (p = 0.008), male waist circumference (p < 0.001), systolic blood pressure (BP) (p = 0.005), diastolic BP (p < 0.001), and glycated hemoglobin (HbA1c) (p < 0.001), and increase in high-density lipoprotein (HDL) cholesterol (p = 0.008). However, the ICT group showed a significant decrease in male waist circumference (p < 0.001), diastolic BP (p = 0.003), and HbA1c (p < 0.001), and increase in HDL cholesterol (p = 0.032). The magnitude of change for most indicators tended to be highest for ICT participants (used the app ≥5 times/month). Both groups reported raised awareness on BP and weight. The app use program did not have a major impact after the observation period. Proper action requires frequent use of the app to enhance best results.

Pneumomediastinum and Subcutaneous Emphysema after High Pressure Air and Sand Injection Injury to the Upper Arm

We present a rare case of a 47-year-old man who developed pneumomediastinum and subcutaneous emphysema after a high pressure hose accidentally injected air and sand particles into his right upper arm. On presentation, he complained of dyspnoea and chest pain. He had palpable subcutaneous emphysema extending from the upper arm to his neck, face, and trunk. Plain X-ray films and computed tomography showed pneumomediastinum and subcutaneous emphysema, but no sand particles. Conservative treatment was done with close observation, and serial radiographs were obtained. There was complete resolution of the mediastinal and subcutaneous air after about two weeks with no evidence of infection. This was an extremely rare case of pneumomediastinum and severe subcutaneous emphysema occurring after accidental air injection injury to the upper arm. With regard to how air entered the mediastinal cavity, possible pathways are discussed. (Hong Kong j.emerg.med. 2014;21:51-54)

Cerebral CT angiography using a small volume of concentrated contrast material with a test injection method: optimal scan delay for quantitative and qualitative performance

OBJECTIVES

The objective of this study was to determine the optimal scan delay quantitatively and qualitatively in cerebral CT angiography (CTA) with a test injection method at the circle of Willis (cW).

METHODS

66 consecutive patients suspected of having unruptured intracranial aneurysms underwent CTA using 40 ml of 370 mg iodine ml(-1) contrast material (CM). After the time until CM arrival at the cW (T(cW)) was calculated, scan delay was divided into three groups according to T(cW) and scan duration (SD) between the second cervical vertebra and cW as follows: [(T(cW)+6)-SD] in 21 patients (Group A); [(T(cW)+8)-SD] in 23 patients (Group B); and [(T(cW)+10)-SD] in 22 patients (Group C). Arterial and venous attenuation in the intracranial vessels was measured. Mean attenuation values were compared quantitatively. The arterial enhancement and venous overlap at the cW and above the cW were qualitatively compared among the three groups.

RESULTS

Mean arterial attenuation in Groups B and C was significantly higher than that in Group A. Mean venous attenuation in Group C was significantly higher than those in Groups A and B. Arterial enhancement above the cW showed a significant difference between Groups A and C, and at the cW between Groups A and B, and Groups A and C. There was a significant difference in venous overlap among the three groups, except for that at the cW between Groups B and C.

CONCLUSIONS

Setting scan delay as [(T(cW)+8)-SD] s can produce the best performance both quantitatively and qualitatively.

Comparison of different volumes of saline flush in the assessment of perivenous artefacts in the subclavian vein during cervical CT angiography

OBJECTIVES

The aim of this study was to examine attenuation values in the central vein and perivenous artefacts at the subclavian vein in cervical CT angiography (CTA) when using 40 ml contrast material (CM) followed by different volumes (25 ml vs 40 ml) of saline flush (SF).

METHODS

61 patients underwent CTA between the aortic arch (AA) and distal to the circle of Willis (cW). After calculating test-bolus time to peak enhancement at the cW (Tc), scanning delay was represented as [(Tc + 4) - scan duration between AA and cW] s. 28 patients (Group A) received 40 ml of 370 mg iodine (I) ml(-1) CM followed by 25 ml of SF, and 33 patients (Group B) received the same CM followed by 40 ml of SF, both administered through the right antecubital vein. Arterial attenuation was measured at seven points in the aorto-carotid artery and at three points in the vertebrobasilar artery. Venous attenuation in the central vein was measured at four points. Mean attenuation values were analysed quantitatively. Axial and post-processing three-dimensional images were assessed qualitatively.

RESULTS

When Groups A and B were compared, there were no differences in the mean attenuation values in either the aorto-carotid artery (p=0.78) or the vertebrobasilar artery (p=0.82). Mean venous attenuation values were lower (p=0.002) in Group B than in Group A. Although the qualitative assessment of arterial images showed no differences between the two groups overall, perivenous artefacts at the subclavian vein were assessed as less prominent (p<0.01) in Group B.

CONCLUSIONS

When compared with CTA followed by 25 ml of SF, CTA followed by 40 ml of SF can reduce venous attenuation values and perivenous artefacts at the subclavian vein.

Comparison of 40 and 60 milliliters of contrast in assessment of the carotid artery by computed tomography angiography

BACKGROUND

Although fast acquisition of multidetector-row computed tomography (MDCT) can make it possible to acquire sufficient early vascular enhancement using small volumes and high concentrations of contrast material (CM), there are still some problems with nephrotoxicity and costs related to CM.

PURPOSE

To compare the qualitative and quantitative performance in cervicocranial CT angiography (CTA) using two different iodine volumes and concentrations of CM.

MATERIAL AND METHODS

CTA ranging from the aortic arch (AA) to distal to the circle of Willis (cW) was performed on a 32-MDCT system. Fifty-eight patients were randomly divided into two groups: group A (29 patients) received 60 ml of 300 mg I/ml CM, and group B (the other 29 patients) received 40 ml of 370 mg I/ml CM. Time to peak arterial enhancement at cW (T(c)) was calculated. As scan speed was 96.9 mm/s and injection rate was 4.0 ml/s, scanning delay was individually decided according to T(c) and scan duration between AA and cW. Arterial attenuation along the z-axis at eight points in the carotid-cerebral artery and venous attenuation of the internal jugular vein (IJV) at carotid bifurcation were measured. Mean attenuation values were then quantitatively analyzed. Postprocessing images were qualitatively assessed.

RESULTS

Arterial attenuation profiles revealed maximum attenuation at the distal common carotid artery in both groups. Although there were no significant differences in mean arterial attenuation in group A versus group B (402+/-70 HU vs. 407+/-67 HU; P=0.78), venous attenuation of the IJV was lower in group B than in group A (114+/-57 HU vs. 224+/-81 HU; P<0.001). Although arterial images demonstrated no difference qualitatively between the two groups, the venous contamination of IVC was less prominent in group B.

CONCLUSION

Although a different amount of CM was administered in both groups, quantitative and qualitative arterial images did not show significant differences between the two groups.

Selective expansion of the CD14(+)/CD16(bright) subpopulation of circulating monocytes in patients with hemophagocytic syndrome

Overproduction of proinflammatory cytokines is characteristic of hemophagocytic syndrome (HPS), a highly lethal inflammatory disease. Peripheral blood monocytes include two distinct subpopulations according to surface antigen expression: a major type, CD14(+)/CD16(-) (classical monocytes), and a minor type, CD14(+)/CD16(bright) (proinflammatory monocytes). Among peripheral blood monocytes from HPS patients, CD14(+)/CD16(bright) cells were increased, together with lipopolysaccharide-induced production of tumor necrosis factor (TNF)-alpha and interleukin (IL)-6. By three-color immunofluorescence, CD14(+)/CD16(bright) monocytes exhibited more intense human leukocytic antigen DR than CD14(+)/CD16(-) monocytes, consistent with greater maturity. Serum IL-6, TNF-alpha, and IL-8 were increased in HPS patients. A sensitive inflammatory marker, neutrophil CD64 expression, also was significantly elevated in HPS patients. In conclusion, expansion of proinflammatory monocytes and increased expression of neutrophil CD64 appeared to be important in the pathophysiology of HPS. Expansion of CD14(+)/CD16(bright) monocytes and neutrophil CD64 expression could serve as indicators of the inflammatory state in HPS.

Height, weight, and alcohol consumption in relation to the risk of colorectal cancer in Japan: a prospective study

Colorectal cancer incidence in relation to body size, smoking, and alcohol consumption was studied in a cohort of 29 051 city residents of Japan. In 1992, each participant completed a self-administered questionnaire on sociodemographic characteristics, drinking, cigarette smoking, diet, exercise, and reproductive and medical histories. The response rate was 92%. From 1993 to 2000, 161 men and 134 women were diagnosed with colorectal cancer at two major hospitals in the city. Relative risks and 95% confidence intervals were calculated by using Cox proportional hazard models. A positive relation between height and colorectal cancer was seen in both sexes, controlling for age, body mass index (BMI), smoking and drinking habits, and years of education. The findings were statistically significant only for men (relative risk 2.13 for the tallest compared with the shortest height tertile; 95% confidence interval=1.26-3.58). Body mass index was also associated positively with colon cancer risk for men, whereas the pattern for women was not clear. There was a positive association between pack-years of cigarette smoking and the risk of rectal cancer in men. A positive dose-response relation between alcohol consumption and colon cancer risk was observed for men and women.

Role of the mitochondrial permeability transition and cytochrome C release in hydrogen peroxide-induced apoptosis

We investigated the role of the mitochondrial inner membrane permeability transition and subsequent release of cytochrome c into the cytosol during oxidative stress-evoked apoptosis. Sublethal oxidative stress was applied by treating L929 cells with 0.5 mM H2O2 for 90 min. Then the cellular localization of cytochrome c was examined by immunofluorescent staining and Western blotting. H2O2 treatment caused the permeability transition and pore formation, resulting in membrane depolarization and translocation of cytochrome c from the mitochondria into the cytosol. Pretreatment with cyclosporin A and aristolochic acid (to inhibit pore formation) significantly attenuated a reduction of the mitochondrial membrane potential, as well as signs of apoptosis such as DNA fragmentation, increased plasma membrane permeability, and chromatin condensation. Therefore, exposure to H2O2 caused the opening of permeability transition pores in the inner mitochondrial membrane. An essential role of cytosolic cytochrome c in the execution of apoptosis was demonstrated by its direct microinjection into the cytosol, thus bypassing the need for cytochrome c release from the mitochondrial intermembrane space. Microinjection of cytochrome c caused caspase-dependent apoptosis.

Developmental expression and localization of IA-2 mRNA in mouse neuroendocrine tissues

Islet antigen (IA)-2 is a novel autoantigen of insulin-dependent diabetes mellitus (IDDM), and belongs to a new class within the receptor-type protein tyrosine phosphatase (PTP) family characterized by lack of PTP enzymatic activity with conventional substrates. Its expression is restricted primarily to the pancreas, pituitary, and brain with the highest level in the brain. IA-2 mRNA expressions in the brain, pituitary and pancreas of 1-, 4-, and 8-week-old mice were examined. In situ hybridization of the brain revealed that IA-2 mRNA was expressed in the cerebral cortex, hippocampus, thalamus, choroid plexus, hypothalamus, Purkinje cells, and granular layer of the cerebellum. In the pituitary, IA-2 mRNA was located in the anterior and posterior pituitary by in situ hybridization. The pattern of IA-2 mRNA expression in normal male mouse brain at 1, 4, and 8 weeks of age by the Northern blot analysis was similar to that in the pituitary by RT-PCR analysis. The expression level was higher at 4 weeks and lower at 1 week of age. In the pancreas, IA-2 mRNA expressions detected by RT-PCR were highest at 8 weeks of age. These results indicated that the amount of mRNA expression increased in accordance to development in brain, pituitary, and pancreas.

Anterior dislocation of the subtalar joint: a case report

We report a very rare case of anterior dislocation of the subtalar joint. Forceful supination of the foot and dorsiflexion of the ankle was considered the cause of the injury in this case. Closed reduction was successful for the talocalcaneal component of subtalar joint, although surgery was subsequently performed because of the residual subluxation of the midtarsal joint including the talonavicular component of subtalar joint and the associated fracture of the lateral process of the talus. Satisfactory results were shown at three-year follow-up.

Diet and colorectal adenoma in Japanese males and females

PURPOSE

The purpose of this study was to assess the relationship between risk of colorectal adenoma and dietary intake of nutrients and foods.

METHODS

In 1992, diet was assessed by a semiquantitative food-frequency questionnaire in a cohort of the Takayama Study in Japan. Patients were 181 male and 98 female cohort members who were newly histologically proved to have colorectal adenoma at colonoscopic examination between January 1, 1993, and December 31, 1995. Controls were 12,607 males and 15,754 females who had no history of colorectal polyp, adenoma, and cancer at baseline (1992) and were not diagnosed to have these diseases during the follow-up period.

RESULTS

In males, the risk of adenoma was significantly associated with intake of animal protein and vitamin A (relative risk, 1.42; 95 percent confidence interval, 1.00-2.04; and relative risk, 1.51; 95 percent confidence interval, 1.04-2.20, for the highest vs. lowest tertiles, respectively; P for trend = 0.048 and 0.03, respectively) after controlling for age, years of smoking, and alcohol intake. A significantly inverse association was observed for carbohydrate intake after controlling for the covariates (relative risk, 0.52; 95 percent confidence interval, 0.32-0.82, for the highest vs. lowest tertiles; P for trend = 0.02). Intakes of animal fat and cholesterol were marginally associated with risk of adenoma.

CONCLUSION

Some dietary components such as animal protein and carbohydrate, which have been associated with risk of colorectal adenoma or cancer in western populations, were also associated with risk of colorectal adenoma in the Japanese population.

Tumor necrosis factor-alpha plus actinomycin D-induced apoptosis of L929 cells is prevented by nitric oxide

Treatment with the nitric oxide-(NO)-generating compound S-nitroso-N-acetylpenicillamine protected cul-tured L929 cells from apoptosis induced by tumor necrosis factor-alpha (TNF-alpha) plus actinomycin D, as determined by the detection of DNA fragmentation and morphological changes. NO also prevented an enhancement of the production of reactive oxygen intermediates by TNF-alpha plus actinomycin D, as assessed by the oxidation of dihydrorhodamine 123 and hydroethidine. Because the inhibition of mitochondrial respiration by rotenone or antimycin A suppressed the increased oxidation of both dihydrorhodamine 123 and hydroethidine, it was suggested that TNF-alpha accelerated the leakage of reactive oxygen intermediates from the mitochondrial electron transport system. Polarography showed that NO reversibly inhibited mitochondrial respiration at either complexes I-III, II-III, or IV, thus suggesting the inhibition of cytochrome oxidase. Taken together, these findings indicate that the decreased mitochondrial formation of reactive oxygen intermediates in the presence of NO might have a protective effect against TNF-alpha plus actinomycin D-induced apoptosis.

Nitric oxide ameliorates actinomycin D/endotoxin-induced apoptotic liver failure in mice

Liver damage induced by lipopolysaccharide (LPS) in actinomycin D-sensitized mice was initiated by a Fas/CD95-independent apoptotic process that produced DNA fragmentation in hepatocytes followed by an increase of plasma ALT. The metabolic inhibitor actinomycin D blocked most of the LPS-induced increase of plasma nitrite/nitrate levels, as did administration of a nitric oxide synthase inhibitor, N(G)-monomethyl-l-arginine, which also promoted LPS-induced apoptotic liver damage. Administration of nitric oxide donors (hydroxylamine, S-nitroso-N-acetylpenicillamine or 2, 2'-(hydroxynitrosohydrazino)bis-ethanamine) resulted in elevation of the plasma nitrite/nitrate level and amelioration of actinomycin D/LPS-induced apoptotic liver damage. The protective effect of nitric oxide against apoptotic liver damage was partially reproduced by a membrane-permeable analog of cyclic GMP. On the other hand, treatment with the soluble guanylate cyclase inhibitor LY83583 overcame the protective effect of nitric oxide against apoptotic liver damage. These results suggest that nitric oxide may regulate programmed cell death in the mouse liver and that induction of genes, including inducible nitric oxide synthase, plays an important role in protecting the liver against LPS-induced apoptotic damage. This effect appears to be mediated, at least in part, via the soluble guanylate pathway.

Cigarette smoking, alcohol use, and colorectal adenoma in Japanese men and women

PURPOSE

The aim of this study was to examine the relationships between smoking and alcohol use and risk of colorectal adenoma.

METHODS

Information about smoking, alcohol use, and other lifestyle variables were obtained prospectively from 14,427 male and 17,125 female residents in a city of Gifu Prefecture, Japan, by a self-administered questionnaire in September, 1992. Colorectal adenomas were newly diagnosed in 181 men and 78 women in this cohort between January, 1993 and December, 1995 by colonoscopic examination at two major hospitals of the city. Gender-specific and site-specific relative risks and 95 percent confidence intervals adjusted for age and for age plus other potential confounding factors were calculated by using logistic regression models.

RESULTS

Thirty or more years of smoking was significantly associated with risk of adenoma in general compared with never having smoked in both men and women (relative risk, 1.60; 95 percent confidence interval, 1.02-2.62 and relative risk, 4.54; 95 percent confidence interval, 2.04-9.08, respectively). Effect of smoking was stronger in the proximal colon. After adjusting for age and carbohydrate intake, total alcohol intake was not associated with risk of adenoma in any site in the colon in men. Sake drinkers were at significantly increased risk of adenoma in general, but the dose-response relationship was not statistically significant. Risk of adenoma in the rectum was not significantly increased for those who consumed >30.3 g/day of ethanol (relative risk, 5.7).

CONCLUSION

These data suggest that smoking is a risk factor of adenoma in Japanese men and women. The role of alcohol, however, is less clear.

Glutathione monoethyl ester and inhibition of the oxyhemoglobin-induced increase in cytosolic calcium in cultured smooth-muscle cells

OBJECT

The mechanism of arterial vasoconstriction caused by oxyhemoglobin production after subarachnoid hemorrhage was investigated.

METHODS

Using a fluorescent Ca++ indicator (fura-2 acetoxymethyl ester), the change in the cytosolic intracellular Ca++ concentration, [Ca++]i. was measured in cultured rat vascular smooth-muscle cells exposed to oxyhemoglobin and other substances. Oxyhemoglobin induced transient elevation of smooth-muscle cell [Ca++]i in either the presence or absence of ethyleneglycol-bis (beta-aminoethylether)-N,N'-tetraacetic acid, indicating that Ca++ released by oxyhemoglobin was derived from [Ca++]i stores. In contrast, methemoglobin had no effect on the smooth-muscle cells. Exposure of the cells to reactive oxygen species generated by xanthine plus xanthine oxidase yielded the same results as with oxyhemoglobin, that is, transient elevation of smooth-muscle cell [Ca++]i. Procaine (a Ca++ channel blocker) failed to inhibit the oxyhemoglobin-induced elevation of [Ca++]i. Ryanodine (a Ca++ channel opener) plus oxyhemoglobin caused markedly greater elevation of [Ca++]i than ryanodine alone, whereas thapsigargin (an adenosine triphosphate [ATP]-dependent Ca++ pump inhibitor) plus oxyhemoglobin had no additional effect when compared with thapsigargin alone. The oxyhemoglobin-induced elevation of [Ca++]i could be blocked by an Fe++ chelator (ferene), but not by an Fe chelator (deferoxamine mesylate). Treatment with either dithiothreitol or glutathione monoethyl ester markedly inhibited the oxyhemoglobin-induced elevation of [Ca++]i.

CONCLUSIONS

These results indicate that Fe++-catalyzed hydroxyl radicals generated from oxyhemoglobin-derived free radicals induce the elevation of [Ca++]i by inhibiting the ATP-dependent Ca++ pump rather than the Ca++ channels in the sarcoplasmic reticulum and that thiols may prevent Ca++ pump inactivation by inhibiting the oxidation of membrane sulfhydryl groups.

Cigarette smoking, alcohol use, and colorectal adenoma in Japanese men and women

PURPOSE

The aim of this study was to examine the relationships between smoking and alcohol use and risk of colorectal adenoma.

METHODS

Information about smoking, alcohol use, and other lifestyle variables were obtained prospectively from 14,427 male and 17,125 female residents in a city of Gifu Prefecture, Japan, by a self-administered questionnaire in September, 1992. Colorectal adenomas were newly diagnosed in 181 men and 78 women in this cohort between January, 1993 and December, 1995 by colonoscopic examination at two major hospitals of the city. Gender-specific and site-specific relative risks and 95 percent confidence intervals adjusted for age and for age plus other potential confounding factors were calculated by using logistic regression models.

RESULTS

Thirty or more years of smoking was significantly associated with risk of adenoma in general compared with never having smoked in both men and women (relative risk, 1.60; 95 percent confidence interval, 1.02-2.62 and relative risk, 4.54; 95 percent confidence interval, 2.04-9.08, respectively). Effect of smoking was stronger in the proximal colon. After adjusting for age and carbohydrate intake, total alcohol intake was not associated with risk of adenoma in any site in the colon in men. Sake drinkers were at significantly increased risk of adenoma in general, but the dose-response relationship was not statistically significant. Risk of adenoma in the rectum was not significantly increased for those who consumed >30.3 g/day of ethanol (relative risk, 5.7).

CONCLUSION

These data suggest that smoking is a risk factor of adenoma in Japanese men and women. The role of alcohol, however, is less clear.

Blood cells with reduced mitochondrial membrane potential and cytosolic cytochrome C can survive and maintain clonogenicity given appropriate signals to suppress apoptosis

Reduction of mitochondrial membrane potential (Psim) and release of cytochrome c from mitochondria appear to be key events during apoptosis. Apoptosis was induced in IC.DP premast cells by the withdrawal of interleukin-3 (IL-3). Psim decreased by 12 hours and cytochrome c was detected in the cytosol at 18 hours. Despite these changes in the mitochondria after 18 hours of IL-3 deprivation, clonogenicity was unaffected when IL-3 was replenished at 18 hours. Activation of v-Abl tyrosine kinase (v-Abl TK) in IC.DP cells before IL-3 depletion led to increased levels of Bcl-XL, prevented reduction of Psim and the release of mitochondrial cytochrome c, and suppressed apoptosis. Activation of v-Abl TK 18 hours after withdrawal of IL-3 when </=10% of the cells had died restored Psim in the remaining cells. More than 40% of cells thus rescued by v-Abl TK between 18 and 42 hours could subsequently form colonies in the presence of IL-3. These data suggest that reduction in Psim precedes loss of mitochondrial cytochrome c in IC.DP cells; that v-Abl TK activation, probably via upregulation of Bcl-XL, prevents loss of Psim and blocks the release of cytochrome c from mitochondria; and that neither of these mitochondrial events is sufficient for commitment to apoptosis.

Hyperammonemia reduces water immersion--restraint stress gastric ulcers in rats

1. The influence of hyperammonemia (produced by the continuous intraperitoneal infusion of ammonium acetate for 6 days) on stress-induced gastric ulcer formation was investigated in conscious rats. 2. Continuous ammonium acetate infusion significantly reduced stress-induced gastric ulceration concomitant with an increase in gastric blood flow, as determined using radioactive microspheres. The serum levels of L-arginine as well as nitrite and nitrate (oxidative byproducts of nitric oxide) were increased by ammonium acetate infusion. 3. Prior administration of N omega-nitro-L-arginine methyl ester, a competitive nitric oxide synthase inhibitor, substantially attenuated the increase in gastric blood flow caused by ammonium acetate infusion and diminished the protective effect on gastric ulceration. 4. These findings suggest that the synthesis of endogenous nitric oxide from L-arginine is accelerated by continuous ammonium acetate infusion when the urea cycle remains intact and has a substantial cytoprotective effect on the stomach, probably through maintaining the gastric mucosal microcirculation.

Reoxygenation-induced mitochondrial damage is caused by the Ca2+-dependent mitochondrial inner membrane permeability transition

Anoxia/reoxygenation injury of isolated rat liver mitochondria was investigated. During anoxia of up to 60 min, the membrane potential was largely preserved and mitochondrial swelling was not observed. Reoxygenation of anoxic mitochondria rapidly caused swelling, cyclosporin A-sensitive Ca2+ efflux, [14C]sucrose trapping, and loss of the membrane potential along with increased generation of reactive oxygen intermediates (ROI). Although pretreatment with catalase and superoxide dismutase completely abolished reoxygenation-induced generation of ROI, mitochondrial damage was not prevented, as indicated by swelling, loss of the membrane potential, a decrease of the ATP content, and cyclosporin A-sensitive Ca2+ efflux. However, addition of the immunosuppressant cyclosporin A or addition of ADP completely prevented the mitochondrial damage induced by reoxygenation. The same protective effect was noted when Ca2+ cycling was prevented, either by chelating Ca2+ with EGTA or by inhibiting Ca2+ reuptake with ruthenium red. These findings indicate that mitochondrial anoxia/reoxygenation injury is caused by the cyclosporin A-sensitive and Ca2+-dependent membrane permeability transition. In contrast, reoxygenation injury does not appear to be triggered by the enhanced production of ROI.

Lipopolysaccharide-mediated hepatic glutathione depletion and progressive mitochondrial damage in mice: protective effect of glutathione monoethyl ester

Overproduction of reactive oxygen intermediates (ROI) may have an important role in the pathophysiology of lipopolysaccharide-mediated liver-injury. This study examined the role of cytosolic and mitochondrial glutathione in protecting hepatocytes from oxidative stress during exposure to lipopolysaccharide. In addition, the possible participation of changes of inner mitochondrial membrane permeability in lipopolysaccharide-induced hepatotoxicity was investigated. The changes of hepatic glutathione content following lipopolysaccharide challenge (2 mg/kg) were measured in mice by reverse-phase high-performance liquid chromatography. Glutathione depletion and a glutathione-rich state were produced by intraperitoneal administration of a specific inhibitor of gamma-glutamyl cysteine synthetase, buthionine sulfoximine (3 mmol/kg), and by administration of glutathione monoethyl ester (10 mmol/kg), respectively. Intracellular ROI generation and the mitochondrial membrane potential were quantified by flow cytometry. Changes of inner mitochondrial membrane permeability in hepatocytes were assessed by radioactive sucrose entrapment. There was increased production of ROI along with depletion of cellular and mitochondrial glutathione in the liver after lipopolysaccharide administration. There was also a change of inner mitochondrial membrane permeability in hepatocytes, with the loss of coupled functions. Buthionine sulfoximine decreased the hepatic antioxidant capacity, worsened mitochondrial function, and reduced the survival rate of the mice. In contrast, glutathione monoethyl ester improved all of these parameters. Glutathione may have an important role in cellular defenses against lipopolysaccharide-induced liver damage in mice, and excessive oxidative stress may precipitate the mitochondrial membrane permeability transition in hepatocytes and lead to cell death.

Activation of neutrophil function by recombinant human granulocyte colony-stimulating factor improves the survival of rats with peritonitis

We examined the effects of recombinant human granulocyte colony-stimulating factor (rhG-CSF) and cefmetazole sodium on survival, neutrophil count, and neutrophil function in rats with peritonitis produced by cecal ligation and puncture. Rats with peritonitis received either rhG-CSF (50 or 100 micrograms/kg) with or without cefmetazole (50 mg/kg) for 3 days, cefmetazole alone, or no treatment and were evaluated as controls. The mortality rate of all treated rats was significantly lower than that of the untreated rats. The survival rate was 57.1% for the rats given both rhG-CSF and cefmetazole, but there was no significant improvement of survival as compared with cefmetazole therapy alone. Treatment with rhG-CSF at 100 micrograms/kg caused the circulating neutrophil count to increase significantly. The phagocytic activity for latex beads and neutrophil H2O2 production showed a greater enhancement by phorbol myristate acetate (PMA) in the untreated rats, thus indicating that neutrophils from treated rats were more activated. These findings show that rhG-CSF can improve survival and neutrophil function in rats with peritonitis, while combined therapy with cefmetazole was also found to be beneficial.

Hyperammonemia inhibits platelet aggregation in rats

The effect of hyperammonemia on ex vivo platelet function and in vivo nitric oxide synthesis was evaluated in rats. In addition, mitochondrial energy production was assessed from the fluorescence intensity of tetramethylrhodamine ethyl ester (TMRE). Continuous ammonium acetate infusion significantly reduced ex vivo platelet aggregation concomitant with a decrease of the platelet cytoplasmic ATP level. The serum level of L-arginine, as well as the levels of nitrite and nitrate (oxidative by-products of nitric oxide), increased with ammonium infusion. Prior administration of N omega-nitro-L-arginine methyl ester, a competitive inhibitor of nitric oxide synthase, did not affect the ammonia-induced rise in L-arginine, but substantially attenuated the associated decrease of platelet ATP and TMRE fluorescence as well as diminishing the anti-aggregatory effect of ammonia infusion. These findings suggest that the synthesis of nitric oxide from L-arginine is accelerated by continuous ammonium infusion and inhibits ex vivo platelet aggregation in the rat, probably by reducing mitochondrial energy production.

Role of reactive oxygen intermediates in lipopolysaccharide-mediated hepatic injury in the rat

Because reactive oxygen intermediates derived from xanthine oxidase may have an important role in the pathophysiology of lipopolysaccharide-mediated tissue injury, we studied hydrogen peroxide generation using 3-amino-1,2,4-triazole inactivation of hepatic catalase and the ratio of xanthine oxidase to xanthine dehydrogenase activity in rat livers after in vivo lipopolysaccharide administration. We also studied the effect of tungsten, a potent inhibitor of xanthine oxidase, on the toxicity of lipopolysaccharide. There was increased hydrogen peroxide production and enhanced proteolytic conversion from xanthine dehydrogenase to xanthine oxidase in rat livers after lipopolysaccharide administration. Feeding rats a tungsten-rich diet for 4 weeks greatly diminished hepatic xanthine oxidase activity and lessened the rise in intracellular hydrogen peroxide production after lipopolysaccharide treatment. Liver damage, as assessed by the serum transaminase levels and mortality, was also ameliorated by the tungsten-rich diet. These findings suggest that hydrogen peroxide derived from xanthine oxidase contributes to the development of systemic toxicity and liver damage after lipopolysaccharide administration.

Valproic acid overdose and L-carnitine therapy

A healthy, nonepileptic 16-month-old child ingested a massive overdose (approximately 4000 mg) of valproic acid (VPA). Upon admission to the hospital, he was in a deep coma and had generalized hypotonicity and no response to pain. His serum and urinary concentrations of VPA were 1316.2 and 3289.5 micrograms/mL, respectively. Urinary concentrations of the beta-oxidation metabolites of VPA were low, whereas concentrations of omega- and omega 1-oxidation metabolites were high. Moreover, 4-en-valproate (a potential hepatotoxin) was detected in the urine. Gastric lavage and general supportive measures were undertaken, including intravenous infusion to increase urine output and oral L-carnitine to correct hypocarnitinemia. Subsequently, the beta-oxidation metabolites increased, the omega- and omega 1-oxidation metabolites decreased, and 4-en-valproate was no longer detected. The patient recovered completely and was discharged on the eighth hospital day without any sequelae. This case suggests that enhanced drug excretion and L-carnitine supplementation may prevent potentially fatal hepatic dysfunction after VPA overdose.

Xanthine oxidase mediates paraquat-induced toxicity on cultured endothelial cell

The role of xanthine oxidase in paraquat toxicity was investigated using cultured bovine pulmonary artery endothelial cells. Exposure to paraquat 0.1 mM was done for 24 hr with or without tungsten pretreatment and in the presence or absence of xanthine oxidase inhibitors. Exposure to paraquat significantly increased O2- production and relative xanthine oxidase activity (xanthine oxidase activity divided by total xanthine dehydrogenase plus xanthine oxidase) while depressing cell growth. In contrast, tungsten and allopurinol inhibited the increase of xanthine oxidase activity and decreased O2- release. Cell injury was assessed by leakage of lactate dehydrogenase and by fluorescein diacetate staining; it was found that oxidase inhibitors (both allopurinol and tungsten) reduced paraquat cytotoxicity. Thus the toxicity of paraquat was at least partly due to intracellular O2- production mediated by xanthine oxidase and the subsequent formation of other free radicals.

DNA damage induced by tumour necrosis factor-alpha in L929 cells is mediated by mitochondrial oxygen radical formation

Treatment of L929 cells with tumour necrosis factor-alpha (TNF-alpha) plus actinomycin D induced DNA damage (indicated by the appearance of a sub-G1 peak due to extracellular leakage of low molecular weight DNA following DNA fragmentation) before significant cell lysis occurred. The DNA damage occurred in parallel with a decrease of the intracellular total glutathione content and an increase of intracellular reactive oxygen intermediates (ROI), as indicated by increased dihydrorhodamine 123 oxidation. Because the inhibition of mitochondrial respiration suppressed the increase of dihydrorhodamine 123 oxidation and DNA damage as well as the decrease in the total glutathione content, it was suggested that increased mitochondrial formation of ROI was responsible for DNA damage after TNF treatment. Deferoxamine (a ferric iron chelator) and dithiothreitol (a sulfhydryl reagent) both prevented DNA damage and cell killing, indicate that hydroxyl radicals generated from O2- and H2O2 produced by the mitochondria in a process catalysed by iron contributed to DNA damage and that this pathway may be involved in TNF-alpha-induced cytotoxicity. An inhibitor of poly(ADP)-ribose polymerase (3-aminobenzamide), worsened DNA damage, but was protective against cell lysis, suggesting that DNA repair subsequent to injury was more important than DNA damage per se in development of TNF-alpha cytotoxicity.

Hypoxia alters the energy metabolism and aggregation of washed human platelets

Washed human platelets were incubated under hypoxic and normoxic conditions to investigate the influence of oxygen deprivation on energy metabolism and aggregation. The maximum aggregation rate, oxygen consumption, lactate production, and adenine nucleotide content were measured. Hypoxic incubation decreased the oxygen burst and maximum aggregation induced by thrombin, and accelerated anaerobic glycolysis. ATP and ADP levels were preserved, but the hypoxanthine level increased in the incubation medium and the platelet AMP level and adenylate energy charge decreased compared with normoxic incubation. Thus, anaerobic glycolysis failed to compensate for impaired oxidative phosphorylation during hypoxic incubation, suggesting that oxidative energy is essential for full platelet function.

Flow cytometric analysis of the direct toxic effects of paraquat on cultured MDCK cells

We used flow cytometry to assess the cell cycle kinetics of cultured Maden Darby canine kidney cells after exposure to paraquat. Fluorescein diacetate fluorescence was used as a marker of cell viability, while bromodeoxyuridine incorporation was detected with a monoclonal antibody and propidium iodide staining to assess DNA synthesis. Flow cytometry was performed immediately, 48 h and 96 h after exposure to paraquat for 24 h. Lactate dehydrogenase release was also measured to determine the extent of cytolysis. Flow cytometry of paraquat-treated cells showed a marked increase of the S phase population immediately after exposure, at a time when there was no increase of lactate dehydrogenase release. In contrast, the cell cycle profile returned towards normal at 48 and 96 h after paraquat exposure, but lactate dehydrogenase release increased. These findings indicate that paraquat arrested cells in the S phase and that inhibition of DNA synthesis by this agent appeared to influence cell viability because S phase block occurred before cytolysis. In addition, this method proved useful for assessing the effects of paraquat on DNA synthesis by cultured cells.

Oxidative damage to mitochondria is mediated by the Ca(2+)-dependent inner-membrane permeability transition

The ability of O2 metabolites derived from the xanthine-xanthine oxidase system to inhibit mitochondrial function was examined using freshly isolated rat liver mitochondria. Under 2,4-dinitrophenol-uncoupled conditions, mitochondria exposed to free radicals exhibited a significant decrease in O2 consumption supported by NAD(+)-linked substrates, but showed almost no change in O2 consumption in the presence of succinate and ascorbate. Oxidative stress caused the loss of intramitochondrial nicotinamide nucleotides, and addition of NAD+ fully prevented any fall in O2 consumption with NAD(+)-linked substrates. The activity of electron-transfer complex I (NADH oxidase and NADH-cytochrome c oxidoreductase) and the energy-dependent reduction of NAD+ by succinate were unaltered by oxidative stress. Exposure to free radicals also had an uncoupling effect at all three coupling sites. The degree of mitochondrial swelling was closely correlated with the inhibition of State-3 oxidation of site-I substrates and with the increase in State-4 oxidation of succinate. The immunosuppressive agent cyclosporin A completely prevented the mitochondrial damage induced by oxygen free radicals (swelling, Ca2+ release, sucrose trapping, uncoupling and selective inhibition of the mitochondrial respiration of site-I substrates). The same protective effect was found when Ca2+ cycling was prevented, either by chelating Ca2+ with EGTA or by inhibiting Ca2+ reuptake with Ruthenium Red. These findings suggest that the deleterious effect of free radicals on mitochondria in the present experimental system was triggered by the cyclosporin A-sensitive and Ca(2+)-dependent membrane transition, and not by direct impairment of the mitochondrial inner-membrane enzymes.

Increased platelet aggregation and fatty acid oxidation in diabetic rats

The effects of diabetes on fatty acid oxidation in platelets was determined in streptozotocin-induced diabetic rats. In platelets isolated from diabetes, the oxygen consumption which reflects mainly the degree of fatty acid oxidation and ADP- and thrombin-induced aggregation were increased as compared to non-diabetic rat platelets. Carnitine palmitoyltransferase I (CPT I), the rate-limiting enzyme for fatty acid oxidation, in platelets obtained from diabetes showed a higher Vmax for palmitoyl-CoA and an increased I50 (concentration giving 50% inhibition of CPT I activity) for malonyl-CoA inhibition. These changes observed in fatty acid oxidation in platelets derived from diabetes returned to the control levels after insulin therapy. When platelets were stimulated with thrombin, platelet CPT I activity increased over time in both diabetic and non-diabetic rats. From these findings, fatty acid oxidation in platelets, as in the liver, is likely to be regulated by insulin and both increased CPT I activity and decreased sensitivity to malonyl-CoA inhibition are attributable to enhanced platelet fatty acid oxidation in diabetic rats.

Accelerated hepatic lipid synthesis in fasted septic rats

We examined changes in the enzyme activities and metabolites related to hepatic fatty acid synthesis in fasted rats with sepsis produced by cecal ligation and puncture. Sepsis stimulated the in vivo incorporation of tritiated water into hepatic fatty acids and nonsaponifiable lipids. The activities of acetyl-CoA carboxylase, ATP-citrate lyase, and NADPH-generating enzymes (glucose-6-phosphate dehydrogenase and malic enzyme), the tissue levels of citrate and malonyl-CoA, and the dephosphorylation of carboxylase were increased in the livers of fasted septic rats compared with fasted sham-operated control rats. These results indicate that sepsis stimulated hepatic lipogenesis and sterologenesis in fasting rats. Furthermore, sepsis reduced the specific activity of hepatic mitochondrial carnitine palmitoyltransferase and raised that of glycerophosphate acyltransferase, suggesting an increased diversion of cytosolic acyl-CoA towards esterification. These intrahepatic metabolic changes strongly suggest that sepsis causes anabolic action on hepatic lipid metabolism.

Clinical evaluation of the effects of direct hemoperfusion on amino acid profiles

We observed significant changes in serial aminograms during direct hemoperfusion (DHP) in clinical cases and decided to evaluate the effects of the procedure on amino acid profiles. DHP at 100 ml/min was carried out for 6 h in patients with drug intoxications. Pre- and post-column aminograms were obtained 0.5, 1, 2, 3, 4, 5 and 6 h from the beginning of DHP. Nonmolecular-weight-dependent adsorption of some amino acids to the column was observed. Methionine (MET), isoleucine (ILE), leucine (LEU), tyrosine (TYR), phenylalanine (PHE) and arginine (ARG) had high adsorption rates. Blood concentrations of TRY, PHE, TRY and histidine (HIS) were significantly reduced. Although both branched-chain amino acids (BCAA) and aromatic amino acids (AAA) were initially adsorbed by the column, AAA recovery was slow.

Effects of 2-tetradecylglycidic acid on rat platelet energy metabolism and aggregation

We investigated the role of energy supplied by long-chain fatty acid oxidation in rat platelet function. Inhibition of the mitochondrial uptake of long-chain fatty acids was achieved by treating rats with 2-tetradecylglycidic acid (TDGA), a potent inhibitor of the overt form of carnitine palmitoyltransferase (CPT-I). The maximum aggregation rate (MAR), CPT-I activity, lactate production, oxygen consumption and adenine nucleotide content of isolated rat platelets were then studied in vitro. 4 h after the in vivo administration of TDGA, the CPT-I activity in saponin-permeabilized platelets was nearly completely inhibited along with a significant reduction in the MAR induced by ADP, thrombin and ionophore A23187. The ATP level, adenylate energy charge (ATP + 1/2 ADP)/(ATP + ADP + AMP) and ATP/ADP ratio in the platelet cytoplasmic pool were also reduced. Platelets from TDGA-treated rats showed lower oxygen consumption rates in both the basal respiratory and oxygen burst states. These results indicate that mitochondrial long-chain fatty acid oxidation coupled to oxidative phosphorylation is an important energy source in rat platelets and is probably involved in the maintenance of platelet function. Enhanced in vitro lactate production in platelets from TDGA-treated rats may have resulted from a compensatory increase in glycolysis which only partly compensated for impaired long-chain fatty acid oxidation.

Changes in brain ECF amino acids in rats with experimentally induced hyperammonemia

Using microdialysis, we studied brain extracellular fluid (ECF) amino acid metabolism in rats with experimentally induced hyperammonemia and regional elevation of brain ECF ammonia levels. The total brain ECF amino acid level was increased by an elevation of the blood ammonia level. Hyperammonemia elevated brain ECF aromatic amino acids and reduced arterial blood branched chain amino acids. When rats with hyperammonemia were intravenously administered norleucine, the brain ECF norleucine level rose markedly, suggesting increased permeability of the blood-brain barrier. When rats with hyperammonemia were infused with a branched chain amino acid-rich preparation, the elevated brain ECF aromatic amino acids level was not suppressed. Following local intracerebral ammonia infusion, only glutamate levels showed a marked elevation. These results suggest that impairment of the blood-brain barrier related to hyperammonemia increases the inflow of low molecular weight substances including amino acids. Furthermore, the ammonia-induced increase of glutamate in the cerebral ECF suggests that high ammonia levels may increase the excitability of the brain. Thus, ammonia may serve as a key factor in the onset of hepatic encephalopathy.

Changes of hepatic fatty acid metabolism produced by chronic thioacetamide administration in rats

Hepatic mitochondrial functions related to fatty acid metabolism, including the respiratory control ratio, fatty acid oxidative capacity and carnitine palmitoyltransferase I activity, were studied in vitro with mitochondria isolated from rats treated with thioacetamide for up to 12 wk. The levels of ketone bodies, carnitine, carnitine esters and malonyl-coenzyme A were also determined in liver extracts. Polarography of mitochondrial respiration from succinate or glutamate plus malate showed a lower respiratory control ratio in thioacetamide-treated rats, whereas uncoupled oxygen consumption was not altered. This suggests that the mitochondrial respiratory chain capacity remained intact in the thioacetamide-treated rats. The oxygen consumption associated with palmitoyl-coenzyme A and palmitoyl-L-carnitine oxidation by isolated liver mitochondria was increased by thioacetamide treatment on both a per-mitochondrial protein and a per-total liver basis. The carnitine palmitoyl-transferase I activity; the tissue levels of ketone bodies, carnitine and carnitine esters; and the beta-hydroxybutyrate/acetoacetate ratio were all higher in the livers of thioacetamide-treated animals than in control livers, whereas the hepatic malonyl-coenzyme A level was decreased by thioacetamide. These results indicate the increased diversion of cytosolic long-chain acyl-coenzyme As into the mitochondria for beta-oxidation rather than their esterification and use in lipogenesis. These intrahepatic metabolic changes induced by chronic thioacetamide administration may reflect the whole-body catabolic state and can be seen as adaptive for maintaining energy homeostasis under conditions of impaired glucose tolerance.

The role of xanthine oxidase in paraquat intoxication

The role of xanthine oxidase in the mechanism of paraquat toxicity was assessed by in vitro and in vivo experiments. Paraquat stimulated the reduction of cytochrome c by xanthine-xanthine oxidase system in vitro. Paraquat, when added in vitro, stimulated hypoxanthine-dependent superoxide production in the cytosol of rat lung. Tungsten-feeding inhibits xanthine oxidase activity in a variety of tissues in experimental animals. Its therapeutic effect on paraquat intoxication was studied in this paper. In rats fed a tungsten-enriched diet for 5 weeks prior to intraperitoneal injection of 50 mg/kg paraquat dichloride, the mortality decreased significantly compared with rats fed a standard diet. Pretreatment with oxypurinol (1000 mg/kg, s.c.) also ameliorated the paraquat toxicity in rats. We conclude that xanthine oxidase plays an important role in paraquat toxicity and that xanthine oxidase inhibitors may become antidotes for paraquat intoxication.

Characterization of overt carnitine palmitoyltransferase in rat platelets; involvement of insulin on its regulation

Saponin-permeabilization (30 micrograms/ml) of the platelet plasma membrane, which enables access of added compounds to mitochondrial overt carnitine palmitoyltransferase (CPT I), was applied to allow the rapid determination of CPT I activity in situ. The effects of diabetes and short-term incubation with insulin in vitro on the kinetic parameters and malonyl-CoA sensitivity of CPT I were also studied in rat platelets. CPT I exhibited ordinary Michaelis-Menten kinetics when platelets were incubated with palmitoyl-CoA. Malonyl-CoA showed an I50 (concentration giving 50% inhibition of CPT activity) of 0.92 +/- 0.11 microM in permeabilized platelets. Platelets obtained from diabetic rats (induced by streptozotocin injection) exhibited an increased Vmax and I50 for malonyl-CoA, and an unaltered Km for palmitoyl-CoA. In contrast, preincubation of platelets prepared from both fed control rats and diabetic rats with insulin (100 and 150 microU/ml) led to a decrease in enzyme activity when assayed with 75 microM palmitoyl-CoA and 0.5 mM L-carnitine as substrates. These in vivo and in vitro results suggested that insulin directly modulated rat platelet CPT I activity, as it does in the liver.