Early introduction of exercise prevents insulin resistance in postnatal overfed rats

Early childhood obesity increases the risk of developing metabolic diseases. We examined the early introduction of exercise in small-litter obese-induced rats (SL) on glucose metabolism in the epididymal adipose tissue (AT) and soleus muscle (SM). On day 3 post-birth, pups were divided into groups of ten or three (SL). On day 22, rats were split into sedentary (S and SLS) and exercise (E and SLE) groups. The rats swam three times/week carrying a load for 30 min. In the first week, they swam without a load; in the 2nd week, they carried a load equivalent to 2% of their body weight; from the 3rd week to the final week, they carried a 5% body load. At 85 days of age, an insulin tolerance test was performed in some rats. At 90 days of age, rats were killed, and blood was harvested for plasma glucose, cholesterol, and triacylglycerol measurements. Mesenteric, epididymal, retroperitoneal, and brown adipose tissues were removed and weighed. SM and AT were incubated in the Krebs-Ringer bicarbonate buffer, 5.5 mM glucose for 1 h with or without 10 mU/mL insulin. Comparison between the groups was performed by 3-way ANOVA followed by the Tukey post-hoc test. Sedentary, overfed rats had greater body mass, more visceral fat, lower lactate production, and insulin resistance. Early introduction of exercise reduced plasma cholesterol and contained the deposition of white adipose tissue and insulin resistance. In conclusion, the early introduction of exercise prevents the effects of obesity on glucose metabolism in adulthood in this rat model.

Magnetic materials: a journey from finding north to an exciting printed future

The potential implications/applications of printing technologies are being recognized worldwide across different disciplines and industries. Printed magnetoactive smart materials, whose physical properties can be changed by the application of external magnetic fields, are an exclusive class of smart materials that are highly valuable due to their magnetically activated smart and/or multifunctional response. Such smart behavior allows, among others, high speed and low-cost wireless activation, fast response, and high controllability with no relevant limitations in design, shape, or dimensions. Nevertheless, the printing of magnetoactive materials is still in its infancy, and the design apparatus, the material set, and the fabrication procedures are far from their optimum features. Thus, this review presents the main concepts that allow interconnecting printing technologies with magnetoactive materials by discussing the advantages and disadvantages of this joint field, trying to highlight the scientific obstacles that still limit a wider application of these materials nowadays. Additionally, it discusses how these limitations could be overcome, together with an outlook of the remaining challenges in the emerging digitalization, Internet of Things, and Industry 4.0 paradigms. Finally, as magnetoactive materials will play a leading role in energy generation and management, the magnetic-based Green Deal is also addressed.

Frontal sinus as an identity and sex indicator

The present study explores the variability of frontal sinuses volume in modern Greeks and their potential use in the forensic identification process.

METHODS

The sample consisted of 102 CT scan images from a modern Greek population. 50 (49%) were male and 52 (51%) were female. Ages ranged from 19 to 101 (mean age 70.6 for males and 69.6 for females). 3D models of the skull were constructed, and volume calculations of the frontal sinus were done with the software Amira 5.4. 10 CT scans were used to extract 2D frontal and lateral images that were used as proxies of antemortem X-rays which were matched to the CT scans using manual craniofacial superimposition.

RESULTS

The average of frontal sinus volume of male was 9,220 mm³ (±SD) and female was 5,880 mm³ (±SD). Mann-Witney test confirmed that mean values were significantly different (P<0.05) between them. Pearson's correlation coefficient showed no evident correlation between the volumes and ages of the skulls in both groups. Using the lateral and anterior oriented radiographs for matching the sinuses, the method produced 60% sensitivity / 99.32% specificity and 80% sensitivity / 99.97% specificity, respectively.

CONCLUSIONS

Even though there are statistically significant differences in the shape and volume between sexes, these are not sufficient to be used as an indicator of sex in worldwide populations. The results indicate that using the anterior view of the frontal sinuses is more consistent in human identification, and that the method proves to be reliable, as long as the sinus is adequately observed on the radiograph.

Exposure to paraquat associated with periodontal disease causes motor damage and neurochemical changes in rats

Exposure to paraquat is possibly involved with the development of several conditions, including neurodegenerative diseases, such as Parkinson's disease (PD). This condition is mainly characterized by the loss of dopaminergic neurons in the nigrostriatal pathway and the development of classical motor symptoms. Etiology includes exposure to environmental factors, such as the paraquat exposure, and inflammatory diseases may exacerbate paraquat neurotoxicity. The aim of the study was to investigate whether the exposure to paraquat associated with the presence of periodontal disease is able to induce motor and biochemical changes in rats similar to that observed in PD. Adult male Wistar rats were sent to ligature. After 48 h, they were sent to daily treatment paraquat (1 mg/kg/day; 2 mL/kg; intragastric) or vehicle for 4 weeks. Twenty-four hours after the last administration, the open field test was performed. The rats were euthanized and the left hemimandibles and striatum were dissected for the analysis of dopaminergic and inflammatory markers. Only the combination of periodontal disease model plus paraquat exposure induced motor impairments. Remarkably, the paraquat exposure increased the ligature-induced alveolar bone loss in hemimandibles. Moreover, only the combination of periodontal disease and paraquat exposure induced the loss of dopaminergic neurons and astrocyte activation in the striatum.

Assessment of the Value of Preoperative Serum Levels of CA 242 and CEA in the Staging and Postoperative Survival of Colorectal Adenocarcinoma Patients

Introduction

CEA is the most frequently used tumor marker in colorectal cancer. There may be an improvement in its efficacy when used in association with CA 242.

Aim

The purpose of this study was to evaluate the efficacy of preoperative serum levels of the tumor markers CA 242 and CEA in the staging and postoperative follow-up of colorectal adenocarcinoma patients.

Patients and Methods

Of a series of 134 patients with colorectal adenocarcinomas 90 underwent radical surgery and 44 palliative surgery. The control group consisted of 22 organ donors. The cutoff serum levels utilized were 5 ng/mL for CEA and 20 U/mL for CA 242. The mortality during follow-up was recorded in order to determine the duration of survival. The data were submitted to statistical analysis using diagnostic tests, the chi-square test, survival analysis (Kaplan and Meier) and ROC curves. A significance level of p ≤ 0.05 was applied.

Results

The sensitivity of CEA in Dukes’ stages A, B, C and D was 27.8%, 32.4%, 32.1% and 66.7%, respectively. The sensitivity of CA 242 was 11.1%, 16.2%, 30.8% and 50%. When both markers were combined, the sensitivity was 33.3%, 48.6%, 40.7% and 72.5%. In the group of patients who underwent radical surgery the mean survival was 60.47 months for those with high preoperative CEA levels, 52.22 months for those with high preoperative CA 242 levels, and 44.80 months for those with elevated levels of both markers. There was a statistically significant difference in survival between patients undergoing radical surgery with elevated CA 242 levels, especially when CEA was also elevated, and patients without elevated CA 242.

Conclusion

Preoperative serum levels of CA 242 showed less efficacy than CEA levels for the staging of colorectal adenocarcinoma patients. Elevated preoperative serum levels of CA 242 alone were related to poor survival, especially in association with high levels of CEA.

Tumor growth reduction is regulated at the gene level in Walker 256 tumor-bearing rats supplemented with fish oil rich in EPA and DHA

We investigated the effect of fish oil (FO) supplementation on tumor growth, cyclooxygenase 2 (COX-2), peroxisome proliferator-activated receptor gamma (PPARγ), and RelA gene and protein expression in Walker 256 tumor-bearing rats. Male Wistar rats (70 days old) were fed with regular chow (group W) or chow supplemented with 1 g/kg body weight FO daily (group WFO) until they reached 100 days of age. Both groups were then inoculated with a suspension of Walker 256 ascitic tumor cells (3×10⁷ cells/mL). After 14 days the rats were killed, total RNA was isolated from the tumor tissue, and relative mRNA expression was measured using the 2^-ΔΔCT method. FO significantly decreased tumor growth (W=13.18±1.58 vs WFO=5.40±0.88 g, P<0.05). FO supplementation also resulted in a significant decrease in COX-2 (W=100.1±1.62 vs WFO=59.39±5.53, P<0.001) and PPARγ (W=100.4±1.04 vs WFO=88.22±1.46, P<0.05) protein expression. Relative mRNA expression was W=1.06±0.022 vs WFO=0.31±0.04 (P<0.001) for COX-2, W=1.08±0.02 vs WFO=0.52±0.08 (P<0.001) for PPARγ, and W=1.04±0.02 vs WFO=0.82±0.04 (P<0.05) for RelA. FO reduced tumor growth by attenuating inflammatory gene expression associated with carcinogenesis.

An e-mail and telephone helpline for sexual problems - results of a 2-year survey of men's sexual concerns

INTRODUCTION

Sexual problems are relatively common in the community. The under-reporting of such problems calls for alternative ways of getting a true perspective of the prevalence of sexual dysfunction.

AIM

To assess and investigate the concerns, ages and nationality of male users of a electronic helpline using it over 2 years (2009-2010).

METHODS

Detailed records were kept of all emails and telephone calls to the helpline which included administrative and clinical queries. The clinical calls and some of the emails were answered by the administrator, while the majority of the emails were answered by a physician. This presentation will deal with the users who emailed for assistance with male sexual dysfunction. (n = 673).

RESULTS

The helpline received a total of 6142 calls over the period of investigation, including administrative and press calls. Men accounted for 88% of the callers about sexual dysfunction. Erectile dysfunction accounted for 68% of the complaints by men who used the e-mail service. Premature ejaculation, loss of sex drive, genital problems and masturbation worries were other concerns that were received. A large number of men from the Middle East and the Indian sub-continent used the email service, mostly for premature ejaculation and masturbation worries, related to their arranged marriage.

CONCLUSIONS

We found confirmation that the commonest sexual complaints in men were of erectile dysfunction and loss of sex drive. Significant correlations were identified between the types of sexual dysfunction and the age and ethnicity of the men who presented with them.

The effect of dietary supplementation with 9-cis:12-trans and 10-trans:12-cis conjugated linoleic acid (CLA) for nine months on serum cholesterol, lymphocyte proliferation and polymorphonuclear cells function in Beagle dogs

Conjugated linoleic acids (CLA), 9-cis:11-trans and 10-trans:12-cis, have been shown to be able to modify some immune cells parameters and plasma lipids in a variety of experiment models. Since lymphocytes and polymorphonuclear cells (PMNC) have a large spectrum functions in the immune response, the knowledge in this field has to be expanded. Beagle dogs were fed a control diet or a CLA supplemented diet for nine months. Blood was collected for biochemical analysis and lymphocyte and PMNC isolation. PMNC were assayed for lysosome content, phagocytic activity and superoxide anion production. A lymphocyte proliferation capacity assay was done. The CLA fed dogs had a 34% reduction in total cholesterol (P < 0.05), 28% in LDL (P < 0.05) and 28% non-HDL-cholesterol (P < 0.05). Neither of the PMNC parameters evaluated demonstrated significant alteration. Lymphocytes from CLA group increased by 45% their mitotic capacity (P < 0.05). Our study demonstrates that CLA can successfully modify the lipid profile of dogs (monogastrics) when fed at reasonable levels, but did not significantly alter inflammatory function as would generally predicted. Further, we had some indication that CLA modulated T cell responsiveness.

The effects of peroxovanadate and peroxovanadyl on glucose metabolism in vivo and identification of signal transduction proteins involved in the mechanism of action in isolated soleus muscle

The insulin-like effects of peroxovanate (POV) and peroxovanadyl (PSV) on rates of lactate formation and glycogen synthesis were measured in isolated incubated soleus muscle preparations. In another experiment rats were made insulin deficient by streptozotocin injection and treated with POV and PSV (0.25 mM) administered in the drinking water and in the course of 7 days glycemia were determined. Also, signal transduction proteins ERK 1 and ERK 2 involved in the insulin signaling were measured in soleus muscle of diabetic rats treated with POV and PSV. Peroxides of vanadate and vanadyl significantly stimulated glucose utilization in soleus muscle preparations in vitro. The stimulation of glycogen synthesis and lactate formation by POV and PSV was similar to insulin stimuli. Rats treated with POV or PSV presented reduction of glycemia, food and fluid intake with amelioration of the diabetic state during the short period of treatment (7 days). POV and PSV modulated ERK1/2 phosphorilation and the insulin administration in these rats caused an addictive effect on phosphorilation state of these proteins.

Effect of chronic fish oil supplementation on renal function of normal and cachectic rats

In the present study we determined the effect of chronic diet supplementation with n-3 PUFA on renal function of healthy and cachectic subjects by providing fish oil (1 g/kg body weight) to female rats throughout pregnancy and lactation and then to their offspring post-weaning and examined its effect on renal function parameters during their adulthood. The animals were divided into four groups of 5-10 rats in each group: control, control supplemented with fish oil (P), cachectic Walker 256 tumor-bearing (W), and W supplemented with fish oil (WP). Food intake was significantly lower in the W group compared to control (12.66 +/- 4.24 vs 25.30 +/- 1.07 g/day). Treatment with fish oil significantly reversed this reduction (22.70 +/- 2.94 g/day). Tumor growth rate was markedly reduced in the P group (16.41 +/- 2.09 for WP vs 24.06 +/- 2.64 g for W). WP group showed a significant increase in mean glomerular filtration rate compared to P and control (1.520 +/- 0.214 ml min-1 kg body weight-1; P < 0.05). Tumor-bearing groups had low urine osmolality compared to control rats. The fractional sodium excretion decreased in the W group compared to control (0.43 +/- 0.16 vs 2.99 +/- 0.87%; P < 0.05), and partially recovered in the WP group (0.90 +/- 0.20%). In summary, the chronic supplementation with fish oil used in this study increased the amount of fat in the diet by only 0.1%, but caused remarkable changes in tumor growth rate and cachexia, also showing a renoprotective function.

Effects of fish oil on the central nervous system: a new potential antidepressant?

In the last 100 years major depression has increased worldwide. In this study we provided coconut fat (CF, rich in saturated fatty acids) or fish oil (FO, rich in n-3 polyunsaturated fatty acids) to female rats throughout pregnancy and lactation and then to their offspring post-weaning and examined lipid brain profile and the possible effect of FO as antidepressant agent in the offspring in adulthood (F1). Rats were submitted to forced swimming test, elevated plus maze, Morris water maze and open field. Peroxidation rate in the cerebral cortex and hippocampus were measured. Docosahexaenoic acid (DHA) concentration in dam's milk, eicosapentaenoic acid (EPA) and DHA concentration in hippocampus and cerebral cortex from F1 rats FO supplemented increased significantly when compared to control (C) and CF rats. Arachidonic acid/EPA ratio in the cerebral cortex and hippocampus decreased in rats submitted to forced swimming test. Peroxidation rate were not different between the groups. Immobility time in the forced swimming test in FO group was reduced (p < 0.01) when compared to C and CF rats. We conclude that lifelong intake of FO was able to induce an antidepressant effect with EPA and DHA concentration increased in the cerebral cortex and hippocampus.

Estudo comparativo de anastomoses colorretais com anel biofragmentável e com grampeador em cães submetidos à irradiação gama pré-operatória

OBJETIVO: Comparar os resultados precoces entre anastomoses colorretais realizadas com anel biofragmentável e com grampeador circular após irradiação pélvica. MÉTODOS: Foram utilizados 40 cães beagle, em dois grupos de 20 animais, submetidos ou não à irradiação gama pré-operatória, com dose única de 500 cGy. Cada grupo foi dividido em dois subgrupos de dez animais, sendo denominado A o grupo em que se utilizou o anel biofragmentável e B aquele em que se empregou o grampeador. Os animais foram submetidos à secção completa do intestino grosso ao nível da junção retossigmóide, com reconstrução do trânsito sendo efetuada por uma das técnicas, após sorteio. Os animais foram sacrificados no sétimo dia de período pós-operatório. RESULTADOS: Houve dois óbitos antes da reoperação: um em animal do grupo teste, por ruptura da anastomose realizada com anel biofragmentável; outro por peritonite generalizada em animal do grupo controle com anastomose efetuada por grampeador. Aderências e infecções de parede ocorreram de forma similar. A análise histológica convencional e a análise morfométrica realizada por computador das áreas de cicatrização anastomótica identificaram comportamento análogo entre os grupos e subgrupos estudados. CONCLUSÃO: Os resultados precoces das técnicas empregadas para anastomose intestinal foram semelhantes nas condições de risco estudadas.

Naproxen, clenbuterol and insulin administration ameliorates cancer cachexia and reduce tumor growth in Walker 256 tumor-bearing rats

Cancer cachexia is characterized by anorexia and intense peripheral catabolism. We examine the potential benefits of combination of different anabolic agents such as insulin and clenbuterol associated to prostaglandin synthesis inhibitor (naproxen) on tumor growth, cachexia and renal function in Walker 256 tumor-bearing rats (WK). Groups were separated into WK, and WK with naproxen (WK N) or naproxen plus clenbuterol (WK NCb) or naproxen plus clenbuterol plus insulin (WK NCbI). Treatment begins at the 4th day after tumor inoculation, at the 14th day they were killed, glycemia, lacticidemia, glycogen content from liver, soleus and gastrocnemius muscles, tumor mass, body weight and kidney function were determined. Glycemia and glycogen content were reduced and lacticidemia increased in WK (p<0.05) as compared to control rats. The glycogen content recovered in all treated groups. Tumor weight was significantly reduced by the different treatments. At the 14th weight change (carcass-initial body weight) in the control increased by 38% and in the WK -2%. Naproxen treatment (WK N) induced an increased by 14%. The inclusion of clenbuterol (WK NCb) and insulin (WK NCbI) by 38 and 41%, respectively. Mean glomerular filtration rate (GFR) increased in the WK (p<0.05) as compared to control, but in the WK NCb the GFR was similar to control. Our results suggest that naproxen is able to reduce tumor growth and its association with insulin and clenbuterol induce mass weight gain and recovery energy fuel.

Indirect costs of migraine in a public Brazilian hospital

OBJECTIVES

To evaluate the indirect costs of migraine affecting employees of a public Brazilian hospital.

BACKGROUND

Migraine is a common primary headache which has a negative influence on the well-being and quality of life, as well as the professional life, of affected individuals.

METHODS

Our series consisted of 846 employees with migraine. The Lost Hours Equivalence Index, which considers both the hours lost due to the absence from work and reduction in productivity, was used to estimate the number of working hours lost due to migraine.

RESULTS

Of the employees with migraine studied, 91% presented a mean 56.9% loss of productivity. The mean number of total lost working hours per month due to migraine was 6.5. The estimated total indirect cost of migraine was R $986 903.77 (US $815 622.54), implicating costs of R $241.30 (US $199.42) per employee per year.

CONCLUSIONS

Based on its impact on life and the resulting costs, migraine should be considered a public health problem and thus measures should be adopted to reduce its impact on the individual and on society.

[Hospital costs of acute headaches in a Brazilian public emergency room unit]

Headache is one of the most frequent complain in the medical practice and a very common cause of medical assistance searching in emergency rooms, leading to considerable high costs. The headache cases assisted during the year of 1996 of an emergency room unit (UE - USP) at Ribeirão Preto, SP, Brazil, had been retrospectively studied. During that year a number of 1254 patients searched the UE - USP with major complain of acute headache, among which 64 needed hospitalization. The estimated costs due to consultation, investigation and clinical treatment of the acute headaches was in the order of R$ 138 573.31 (US$ 76 985.17). The expenses related only to laboratorial exams were R$ 23 801.54 (US$ 13 223.07). The surgical expenses were R$ 5 817.90 (US$ 3 232.17). The total cost was R$ 144 391.21 (US$ 80 217.34) which corresponds to R$ 115.14 (US$ 63.97) per patient. This calculus instigates an additional discussion about the costs and effectiveness of the current public health policy, where the financial resources are less abundant than the State dependant population's needs.

[Migraine prevalence and impact in employees of the clinical hospital of the medical school of Ribeirão Preto-USP]

Headache is a common symptom in the population, with a life prevalence around 90%. It results in an important impact in the life quality of sufferers. The aim of this study is to evaluate the prevalence of migraine among employees of an university hospital (HC), as well as to measure the headache intensity, interference and impact in the daily activities. A total of 1890 employees had answered to a questionnaire which made possible to carry out diagnosis of migraine. Life prevalence of this headache type was 30. 4%. Pain was considered intense, most of the time, by 86% of the migraneurs. It was verified an important impact in the daily life aspects as much during as between the headache attacks. It can be concluded that migraine represents a public health problem among the HC employees. Because migraine brings about an important impact in the life quality of those workers, it is possible that a reduction of working capacity with considerable economic burden exists. This problem deserves, thus, special attention, through a better diagnostic and treatment.

[Comparative study of intestinal anastomosis with manual suture and biofragmentable ring in dogs under corticosteroid administration]

BACKGROUND

This study analyzed intestinal anastomoses by manual suture and by compression with biofragmentable ring under delay of cicatrization administering parenteral corticoids.

MATERIAL AND METHODS

Twenty dogs were divided into two groups: control and test, the latter submitted to intramuscular administration of hydrocortisone hemisuccinate, 25 to 33 mg/kg/day, on the 30th preoperative and 7th postoperative days. During surgery, each animal underwent two colon sections with anastomosis by manual suture in a single extramucous plane and compression with biofragmentable ring. The animals were sacrificed 7 days after the procedure to evaluate the anastomoses.

RESULTS

In the postoperative period, one death occurred in the test group and two in the control group, caused by nonblocked fistula in the anastomoses by ring compression. Statistically, there was a similar incidence of adherences, fistulas, afferent dilatation and obstruction using comparison methods. On microscopy, deficiency in mucous regeneration of the anastomoses by compression was observed. Computerized histological analysis evidenced in the anastomoses by compression, a greater inflammatory reaction, greater edema of the submucous membrane and enlarged scars.

CONCLUSIONS

It was concluded that, with the biofragmentable ring, in colonic anastomosis under delay of cicatrization induced by corticoids, similar results to manual suture regarding to postoperative complications incidence were obtained; ring, however, determined worse mucous regeneration and greater cicatricial inflammatory reaction.

The effect of melatonin chronic treatment upon macrophage and lymphocyte metabolism and function in Walker-256 tumour-bearing rats

Melatonin is the main hormone involved in the neuroendocrine-immune axis. It also presents antitumour activity. To evaluate the role of melatonin on the progression of Walker-256 tumour in rats we determined the effect of the hormone on some biochemical and functional aspects of macrophage and lymphocytes from cachectic rats. An important finding observed in immune cells from tumour-bearing (TB) rats is the impairment on glutamine and glucose metabolism in such cells. These changes are very similar to those observed in pinealectomized rats (PNX). The increased production of lactate and the flux of glucose through the Krebs cycle and the reduction in glutamine consumption seems to be involved in the immunosuppression presented in the TB and PNX animals. Melatonin treatment restored the changes observed in the metabolism of glucose and glutamine and stimulated the proliferation of lymphocytes from tumour-bearing rats. The results indicate that the effect of melatonin upon tumour growth involves the stimulation of the immune system by the hormone.

Glucose metabolism in the erythrocytes of the buffalo (Bubalus bubalis)

14CO2 production from [1-14C] glucose, the rate of glycolysis measured by the value of lactate production and the activities of various enzymes were determined in buffalo erythrocytes. Buffalo red cell glycolytic metabolites were estimated and used for the calculation of the mass action ratios of reactions catalyzed by the glycolytic enzymes of Bubalus bubalis. A comparison of the values of the mass action ratios with the equilibrium constants of the various glycolytic reactions indicate that hexokinase, phosphofructokinase, phosphoglycerate kinase and pyruvate kinase reactions are displaced from equilibrium, suggesting a regulatory role for each of these enzymes in buffalo erythrocyte glycolysis.

Insulin treatment can abolish changes in glucose and glutamine metabolism of lymphocytes and macrophages caused by the implantation of the Walker 256 tumour

Activation of lymphocytes and macrophages by the implantation of tumour cells (10(7) cells per rat) into the left flank of rats increased the conversion of glucose to lactate and of glutamine to glutamate and aspartate and the decarboxylation of [U-14C]-glucose and [U-14C]-glutamine in incubated cells. In addition, the amount of GLUT1 was increased in macrophages. The effect of insulin treatment on glucose and glutamine metabolism of lymphocytes and macrophages activated by Walker 256 tumour implantation was also examined. For this purpose, insulin was injected subcutaneously (4 U/100 g b.w. daily) after the fourth day of tumour implantation and the rats were killed 10 days afterwards. Insulin treatment fully reverted the changes due to tumour implantation in the metabolism of glucose and glutamine in lymphocytes and of glucose in macrophages.

Insulin and prostaglandins as signals between tumor and the host immune system

The development of malignant tissue in vivo is partially favored by the immunosuppression that occurs in cancer patients. However, the signals between tumor and immune tissues remain to be identified. We present evidence that prostaglandins may act as one of these signals by a direct action on cells of the immune system, or by inhibition of insulin secretion which in turn suppresses immune function, or both.

Metabolism of glucose, glutamine and pyruvate in lymphocytes from Walker 256 tumor-bearing rats

This study examined the effect of Walker 256 tumor growth in vivo on the metabolism of glucose, glutamine and pyruvate in lymphocytes. A comparison between the metabolism of Walker 256 tumor cells obtained in vivo with that of lymphocytes was also carried out. Lymphocytes and tumor cells were isolated and incubated for 1 h for the following measurements: lactate production from glucose (5.6 mM) and pyruvate (3 mM), glutamate and aspartate formation from glutamine (3 mM) and decarboxylation of [U-14C]-glucose, [U-14C]-glutamine, [1-14C]-pyruvate and [3-14C]-pyruvate. The presence of the tumor increased lactate production (2.7-fold from glucose and 2-fold from pyruvate), decarboxylation of [U-14C]-glucose (3.7-fold) and [1-14C]-pyruvate (4.4-fold) and the formation of aspartate (6.3-fold) and glutamate (4.6-fold) from glutamine. The conversion of glucose to lactate and CO2 was higher in tumor cells as compared to lymphocytes. Tumor cells also showed a higher production of glutamate and an 8-fold increased decarboxylation rate of [U-14C]-glutamine in tumor cells, which was more active than that of lymphocytes even from tumor-bearing rats. Tumor growth stimulated glucose and glutamine metabolism in lymphocytes; however, the importance of this fact for the function of these cells remains to be elucidated.

Metabolism of a chylomicron-like emulsion in rats with Walker 256 tumor: influence of a polyunsaturated (n-6) compared with a saturated fatty acid-rich diet

OBJECTIVE

Defects in lipid metabolism secondary to development of cancer are frequently observed and, in experimental animals, manipulation of the lipid content of the diet can significantly influence tumor growth. The effects of a high polyunsaturated fat vs a high saturated fat diet upon the chylomicron metabolism of rats bearing Walker 256 tumor were examined.

METHODS

Chylomicron-like emulsions labeled with radioactive lipids were injected into rats bearing the tumor and control rats. The two groups were previously given a high polyunsaturated (n-6) (15% fat) or a high saturated fat diet (15% fat) for 6 weeks. Following injection, plasma samples were collected at 8 time intervals in 60 minutes and tissue fragments were excised after the animals were killed, for determination of the plasma fractional clearance rate (FCR, min-1) and organ uptake of radioactive lipids.

RESULTS

FCR of the emulsion triacylglycerols (TG) and cholesteryl oleate ether (CE) decreased in the tumor-bearing rats fed the polyunsaturated fat-rich diet (FCR-TG control = 0.26 +/- 0.09, tumor = 0.11 +/- 0.04; FCR-CE controls = 0.18 +/- 0.05, tumor = 0.10 +/- 0.02), as did activity of the lipoprotein and hepatic lipases (p < 0.05). This indicates that in this group, the presence of the tumor elicited defective lipolysis and delayed removal of the emulsion from the plasma. In the group fed the saturated fatty acid-rich diet, however, these alterations were not observed (FCR-TG control = 0.21 +/- 0.11, tumor = 0.20 +/- 0.08; FCR-CE control = 0.13 +/- 0.06, tumor = 0.10 +/- 0.05). The uptake by several tissues of the emulsion CE was similar in all rat groups.

CONCLUSION

The saturated fat-rich diet avoids the deficiency in chylomicron lipolysis elicited by the implanted Walker 256 tumor.

The effects of orthovanadate, vanadyl and peroxides of vanadate on glucose metabolism in skeletal muscle preparations in vitro

The insulin-like effects of various vanadium compounds (orthovanadate, vanadyl and peroxides of vanadate) on rates of glucose oxidation, lactate formation and glycogen synthesis were measured in isolated incubated epitrochlearis (mainly type II fibres) and soleus (mainly type I fibres) muscle preparations. There was a small stimulation of the rate of glucose utilisation in soleus muscle preparations in vitro by orthovanadate (1 mM). Orthovanadate or vanadyl, at 1 mM, had little effect on the rates of lactate formation or glycogen synthesis in isolated incubated epitrochlearis muscle preparations. In contrast, peroxides of vanadate (peroxovanadates, at 1 mM) significantly stimulated glucose utilisation in both soleus and epitrochlearis muscle preparations in vitro. The stimulation of the rate of glycogen synthesis was associated with an increase in the percentage of glycogen synthase in the I (or a) form. Peroxovanadates were administered in the drinking water to rats made insulin deficient by streptozotocin treatment. There was no decrease in the elevated level of blood glucose over an 8 day administration period.

Metabolic changes of several adipose depots as caused by aging

In this study, metabolic changes of several adipose depots as caused by aging were investigated. Key enzyme activity of glutaminolysis, pentose-phosphate pathway and Krebs cycle were measured. The rates of lipogenesis from 3H2O, lipoprotein lipase (LPL) activity and rate of lipolysis in vitro were also determined. The results obtained indicate a reduced capacity for lipogenesis in several adipose depots by aging. The authors concluded that hypertrophy of adipose tissue reported during aging is possible due to increased LPL activity and reduced rate of lipolysis.

[Effects of food restriction on the protein and electrolyte composition in the liver and muscles of rats]

Protein and electrolyte disturbances in hepatic and muscle tissues are related to trauma, sepsis, or short term starvation or semistarvation. The consequences of a prolonged semistarvation are poorly understood. For five weeks, male adult rats were offered 50% of the diet until they had a weight loss of 40%, after which protein and electrolyte (Ca++, Mg++, Zn++, Na+, K+) changes in the liver and soleus and extensorum digitorum longus muscles were analyzed. There was a significant weight loss after 5 weeks of semistarvation. Hepatic protein and serum albumin were not changed, but the authors observed a significant muscle protein depletion. A fall in Zn++ levels in the blood was accompanied by a rise in muscle and liver concentrations. The rise in Ca++ and Mg++ concentration in blood and in the muscles might be related to the enhanced proteolysis. Results suggest that the early changes of protein and electrolyte metabolism at tissue level with semistarvation impair muscular and hepatic functions as they delay adequate response to trauma and infection.

Insulin secretion in Walker 256 tumor cachexia

The effect of cachexia on insulin secretion was examined in adult male rats. Isolated islets of Langerhans from Walker 256 tumor-bearing rats secreted less insulin by glucose stimuli as compared with the control group; this was accompanied by significant change in 45Ca2+ outflow rate. Reduced insulin secretion to glucose stimuli in tumor-bearing rats probably led to low insulinemia (one-third). These findings indicate that reduced insulin secretion is probably an important factor for the development of cachexia in Walker 256 tumor-bearing rats.