Pulmonary effects of welding fumes: review of worker and experimental animal studies

BACKGROUND: Approximately one million workers worldwide perform welding as part of their work duties. Electric arc welding processes produce metal fumes and gases which may be harmful to exposed workers. METHODS: This review summarizes human and animals studies which have examined the effect of welding fume exposure on respiratory health. An extensive search of the scientific and occupational health literature was performed, acquiring published articles which examined the effects of welding on all aspects of worker and laboratory animal health. The databases accessed included PubMed, Ovid, NIOSHTIC, and TOXNET. RESULTS: Pulmonary effects observed in full-time welders have included metal fume fever, airway irritation, lung function changes, susceptibility to pulmonary infection, and a possible increase in the incidence of lung cancer. Although limited in most cases, animal studies have tended to support the findings from epidemiologic studies. CONCLUSIONS: Despite the numerous studies on welding fumes, incomplete information still exists regarding the causality and possible underlying mechanisms associated with welding fume inhalation and pulmonary disease. The use of animal models and the ability to control the welding fume exposure in toxicology studies could be utilized in an attempt to develop a better understanding of how welding fumes affect pulmonary health.     

Body fat deposition: effects of dietary fat and two exercise protocols.

We evaluated the effects of two levels of dietary fat (0 and 20g beef tallow/100g diet) and two treadmill exercise protocols (low-intensity, high-intensity) on fat deposition in rats.

Male Wistar rats (n = 50) remained sedentary or were forced to run 840 meters/day, 5 days/week, on a rodent treadmill. Those on the high-intensity protocol covered this distance in less time (38 min) than those on the low-intensity program (60 min). Responses to high-fat (HF) and low-fat (LF) diets were compared within each exercise group for this 8-week study.

High fat feeding, as a single factor, did not affect energy intake, carcass fat, intramuscular fat, or fat associated with any tissue studied. The HF diet also did not affect responses to either exercise protocol. The high-intensity-exercised animals had less carcass fat (LF: 21% less; HF: 33% less), smaller omental fat pads (LF: 20% less; HF: 37% less), and retroperitoneal fat pads (LF: 19% less; HF: 38% less), and lower serum triglyceride levels (LF: 26% less; HF: 41% less) than sedentary rats. Those differences were less marked for the low-intensity-exercise rat. Neither mode of exercise or diet affected lipid concentrations in hindlimb muscles, livers, hearts, or kidneys.

Exercised animals generally had less fat deposition than sedentary rats but this was more pronounced for high-intensity than low-intensity-exercised rats, and was not affected by feeding a 20% beef tallow diet.     

Adverse effects of social pressure to be thin on young women: an experimental investigation of the effects of "fat talk"

OBJECTIVE: Experiments have found that pressure to be thin from the media promotes body dissatisfaction and negative affect, but the effects of social pressure to be thin have not been examined experimentally. Thus, this study tested whether social pressure to be thin fosters body dissatisfaction and negative affect. METHOD: Young women (N = 120) were randomly assigned to a condition wherein an ultra-thin confederate complained about how fat she felt and voiced intentions to lose weight or a control condition wherein she discussed a neutral topic. RESULTS: Exposure to social pressure to be thin resulted in increased body dissatisfaction but not negative affect. The effects were not moderated by initial thin-ideal internalization, body dissatisfaction, or social support. DISCUSSION: Results support the assertion that peer pressure to be thin promotes body dissatisfaction but suggest that this factor may not contribute to negative affect.     

Effect of intravenous fat emulsion on experimental acute pancreatitis

The known relationship of hyperlipidemia and pancreatitis raises the question whether intravenous fat emulsion is detrimental in acute pancreatitis. Pancreatitis was induced in 52 male Sprague-Dawley rats followed by placement of a jugular catheter which was anchored to the back with a Teflon button. The animals were placed NPO in metabolic cages and continuously infused, initially with normal saline. The 37 animals surviving 24 hr were randomly assigned to group I (mean iv intake: glucose 222 kcal/kg/day; amino acids 13.1 g/kg/day) or group II (glucose 191 kcal/kg/day; intravenous fat emulsion 10% 47 kcal/kg/day; amino acids 12.9 g/kg/day). Nine animals were eliminated from the study because of mechanical problems leaving 14 in each group for analysis. Per cent survival on days 3, 5, and 7 was 64, 50 and 36 in group I, and 50, 36 and 36 in group II. Mean urinary amylase excretion was 244 +/- 185 units/day in group I and 262 +/- 127 units/day in group II. There was no significant difference in survival or urine amylase excretion nor in pancreatic histology or gross appearance of the animals between the two groups. In this model of acute pancreatitis, intravenous fat emulsion was not detrimental as measured by survival, urinary amylase excretion, and pancreatic histology.     

In vivo lipogenesis of genetically lean and fat chickens: effects of nutritional state and dietary fat

In vivo lipogenesis was estimated in liver and carcass of male chickens selected for leanness (LL) or fatness (FL) by use of tritiated water. Effects of nutritional state and of a high fat diet (90 g/kg) were examined. Different classes of liver lipids were also measured. Fed birds exhibited enhanced hepatic lipogenesis, which was more pronounced in FL than in LL birds (+73%, mean of three experiments). Extrahepatic lipogenesis was poorly influenced by nutritional state in LL birds and not modified in FL ones. The high fat diet induced a fall in liver triacylglycerol and reduced de novo lipogenesis more drastically in liver than in carcass of both lines. Reduction of carcass lipogenesis was less pronounced in FL than in LL. Starvation led to a fall in liver triacylglycerols, nonesterified fatty acids and free cholesterol. The fat diet had similar but less pronounced effects. In most circumstances FL chickens exhibited a higher liver triacylglycerol content than LL ones. Comparison of fed and refed birds 100 min after the beginning of refeeding showed that de novo lipogenesis did not reach a plateau and differences between lines were still not significant.     

Quantitative review of studies of dietary fat and rat colon carcinoma

A quantitative overview of 14 studies of rat colon carcinogenesis was undertaken to examine the relationship between fat intake, and fat intake by degree of saturation, on the incidence of colon carcinoma while controlling for calorie consumption. Calorie consumption was not recorded in 11 of the 14 studies. Hence, two types of analyses were conducted. The first examines carcinoma incidence as a function of percent fat (by weight), with calories controlled for by including weight gain per week in the analysis. The second estimates calories per day, for studies not providing such information, using weight gain per week and age at death, followed by a joint analysis of estimated fat calories and estimated total calories. With either approach, a rather strong positive relationship between colon carcinoma incidence and fat intake is indicated for Fischer 344 rats, but no association is apparent for Sprague‐Dawley rats. This situation is somewhat clarified when the degree of saturation is taken into account: both strains gave results that suggest a negative relationship between colon cancer incidence and omega‐3 fatty acids intake and a positive relationship with non‐omega‐3 polyunsaturated fat intake among Fischer 344 rats. These analyses suggest an important and specific role for dietary fat in the promotion of rat colon carcinoma.     

Quantitative review of studies of dietary fat and rat colon carcinoma

A quantitative overview of 14 studies of rat colon carcinogenesis was undertaken to examine the relationship between fat intake, and fat intake by degree of saturation, on the incidence of colon carcinoma while controlling for calorie consumption. Calorie consumption was not recorded in 11 of the 14 studies. Hence, two types of analyses were conducted. The first examines carcinoma incidence as a function of percent fat (by weight), with calories controlled for by including weight gain per week in the analysis. The second estimates calories per day, for studies not providing such information, using weight gain per week and age at death, followed by a joint analysis of estimated fat calories and estimated total calories. With either approach, a rather strong positive relationship between colon carcinoma incidence and fat intake is indicated for Fischer 344 rats, but no association is apparent for Sprague-Dawley rats. This situation is somewhat clarified when the degree of saturation is taken into account: both strains gave results that suggest a negative relationship between colon cancer incidence and omega-3 fatty acids intake and a positive relationship with non-omega-3 polyunsaturated fat intake among Fischer 344 rats. These analyses suggest an important and specific role for dietary fat in the promotion of rat colon carcinoma.     

Severe fat embolism: a review of 24 cases

Twenty-four patients suffering from fat embolism syndrome, severe enough to warrant transfer to an artificial ventilation unit, are reviewed. All developed the condition following trauma. Five patients were managed with oxygen therapy and sedation, but the other 19 needed intubation and ventilation to achieve adequate arterial oxygenation. In spite of intensive supportive therapy, 6 patients (who had all required ventilation) died, one due to heparin therapy, the others from progression of the syndrome. A poor prognosis seemed to be associated with young age, a rapidly progressive condition and a continued need for 100 per cent oxygen after institution of artificial ventilation. There seemed to be no relationship between outcome and severity of injury, type of surgical management and time of onset after injury. The clinical features of these patients are discussed with reference to the many unanswered questions that surround this condition.     

Adaptive response of rat pancreatic lipase to dietary fat: effects of amount and type of fat

Pancreatic lipase adapts to changes in dietary fat by parallel changes in synthesis. The adaptation to changes in type of dietary fat (saturation or chain length) is unclear. The effects of changes in amount and type of dietary fat were examined in weanling rats fed for 1 wk diets low in fat (LF) with 10% kcal as corn oil, moderate in fat (MF) with 40% kcal as fat (corn oil, lard, safflower oil, butter, olive oil or coconut oil), or high in fat (HF) with 67% kcal as fat (as for MF). Growth was comparable among rats fed these diets. Pancreatic lipase activity increased in all HF diets (180%) compared to the LF diet. In MF diets, only the highly unsaturated safflower oil increased pancreatic lipase (162%) compared to the LF diet. Food consumption varied, but was not related to the response of pancreatic lipase. When weanling rats were fed diets with 11, 40, 47, 54, 67 and 75% kcal as corn oil, pancreatic lipase activity was not stimulated at or below 47% kcal fat, but was maximally stimulated (twofold) by 54 or 67% fat. These findings suggest that pancreatic lipase activity adapts primarily to the amount of dietary fat and responds to the type of fat only below the threshold level of dietary fat (47% kcal).     

脂肪饮食与相关疾病关系的调查分析

通过对荤食组与素食组(和尚)临床对比分析,发现两组在相关疾病如胆石症、冠心病、高脂血症、高血压、肥胖症、癌症、糖尿病的发病率有非常显著性差异(P<0.005,P<0.001).两组的血脂水平亦有着显著性差别(P<0.005)、P<0.001).结果表明不同饮食结构的人群的相关疾病的发病率有着显著的不同.证明早期限制脂肪饮食的摄入是预防相关疾病的最重要措施.     

The putative effects of green tea on body fat: an evaluation of the evidence and a review of the potential mechanisms

The increase in the prevalence of obesity in recent years has prompted research into alternative methods of modulating body weight and body fat. The last decade has reflected this with a surge in studies investigating the potential of green tea as a natural agent of weight loss, with a view to confirming and elucidating the mechanisms underlying its effect on the body. Currently, it is widely believed that the polyphenolic components present in green tea have an anti-obesogenic effect on fat homeostasis, by increasing thermogenesis or reducing fat absorption among other ways. The data published to date, however, are inconsistent, with numerous putative modes of action suggested therein. While several unimodal mechanisms have been postulated, a more plausible explanation of the observed results might involve a multimodal approach. Such a mechanism is suggested here, involving simultaneous inhibition of the enzymes catechol-O-methyltransferase, acetyl-CoA carboxylase, fatty acid synthase and impeding absorption of fat via the gut. An evaluation of the available evidence supports a role of green tea in weight loss; however the extent of the effects obtained is still subject to debate, and requires more objective quantification in future research.     

Beef patty composition: effects of fat content and cooking method

Patties from ground round, ground chuck , and regular ground beef containing 14%, 19%, and 24% fat, respectively, were cooked by six different methods and analyzed for compositional differences. Cooking methods were electric broiling , charbroiling , roasting, convection heating, frying, and microwave heating. Percent yield, fat, and moisture of cooked patties were significantly affected (p less than .05) by the interaction of fat level and cooking method. Except for patties cooked by broiling or convection heating, patty yields decreased with increasing fat levels. Leaner formulations of ground beef increased in fat percentage with cooking, while patties processed to contain more fat initially decreased in fat percentage following cooking. Microwave cooking always produced patties containing the least fat and caloric content in comparison with other methods. Increasing levels of fat in the raw patty formulation did not appear to affect substantially the total caloric value of the patties following cooking. Cooked patties processed to have 14% fat contained slightly more water and less fat than patties having 24% fat. At current retail prices, cooked patties made to have 14% fat cost +0.20 more per patty than patties produced to contain 24% fat, regardless of the method of cooking.