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Eating disorders
Published in Judy Bothamley, Maureen Boyle, Medical Conditions Affecting Pregnancy and Childbirth, 2020
Obesity is characterised by an increase in the number and/or size of fat cells (adipocytes). Extra calories from carbohydrates, protein and fat are converted into fat stores in adipose (fat) tissue. Thus energy storage is the primary function of adipose tissue but it also has a role in regulating blood sugar, thermal insulation, and the protection of organs as well as metabolic and immune functions. There are two types of adipose tissue: brown adipose tissue (mostly in newborns) and white adipose tissue (WAT), the main type of human fat. Women typically store more fat than men, which is partly influenced by oestrogen. The different deposits of WAT fat, that is, whether it is central or subcutaneous, have different functions and while an increase in total body fat is associated with an increase in morbidity and mortality generally, it is excess fat located around the abdomen that makes the obese individual more at risk of heart disease and diabetes (Ogston, 2006). Fats in these different locations differ in the substances they secrete, which may explain the different morbidity (Powell, 2007).
The Acute Unwanted Effects of Beta2 Receptor Agonist Therapy
Published in Richard Beasley, Neil E. Pearce, The Role of Beta Receptor Agonist Therapy in Asthma Mortality, 2020
Martin J. Kendall, Christine A. Haffner
Free fatty acids (FFAs) provide energy during exercise and stress, and lipolysis, the process of their release from adipose tissue, is stimulated by catecholamines. This action is mediated by beta adrenoceptor activation, although which subtype is involved remains undecided. Lipolysis was originally considered to be under beta1 receptor control.41-43 However, beta1 blockers have less impact on lipolysis than on the heart. Furthermore, beta2 agonist drugs promote lipolysis. Additional support for lipolysis being a beta2-me-diated process is derived from the increase in FFA induced by infusion of dilevalol, a beta blocker with beta2-stimulant properties,44 and a comparison of xamoterol, a partial beta1 agonist, and terbutaline, which demonstrated a far greater lipolytic response to terbutaline.45 Both these studies used normal volunteers. Alternatives are that human fat cell lipolysis is mediated through a mixed pool of receptors or that the receptors are different and called beta3.41 IV salbutamol produced a marked increase in plasma FFAs in normal volunteers46 and pregnant women14 as did nebulized salbutamol.15 Once again, however, asthmatics behave differently; neither inhaled26 nor IV salbutamol16 elevated plasma FFAs. This observation was confirmed by Kallenbach et al.41 and may be explained by the development of tolerance.28
Origins of obesity in human evolution
Published in Anna Bellisari, The Anthropology Of Obesity in the United States, 2016
For humans, the primate legacy is a preference for sweet, carbohydrate-rich fruits and highly prized but rare, nutrient-dense animal flesh, and a herbivore digestive system modified to accommodate much high-quality, fat- and protein-rich food. Like other animals, humans store body fat, but have the unique ability to do so beginning in fetal life and to accumulate virtually unlimited amounts of adipose tissue after birth. Human fat depots are unique in their size and distribution, especially among females whose breast, hip, and thigh adipose tissue deposits are greater than the abdominal fat predominant in males. Thus humans in general and females in particular have evolved a selective advantage over other primates – the superior ability to store, retain, and use energy reserves for body maintenance, activity, and especially reproduction. The highly endangered status of wild ape populations today is in part due to low fertility related to limited energy resources, while human fertility is enhanced by greater energy storage to support reproduction and extended child care.
A New Procedure in Bone Engineering Using Induced Adipose Tissue
Published in Journal of Investigative Surgery, 2021
Randa Alfotawi, Mona Elsafadi, Manikandan Muthurangan, Abdul-Aziz Siyal, Musaad Alfayez, Amer A. Mahmmod
Adipose tissue as a whole (cells and extracellular matrix) has been engineered and used as a graft for soft tissue replacement, and has been used to replace soft tissue volume, particularly breast tissues.11 Adipose tissue engineering techniques provide three-dimensional environments that not only provide an extracellular matrix that mimics physiological microenvironments but also enhance and facilitate cell-cell and cell-matrix interactions.12 Moreover, subcutaneous fat tissue has been tested for bone characteristics in vitro in a study that aimed to explore the osteogenic potency of dedifferentiated fat cells obtained from patients with osteoporosis.13 The transdifferentiation of human fat into osteogenic tissues is possible under suitable conditions.9,13 Adipose tissue can be used as an autologous soft tissue graft, but does have some disadvantages, including having a lower volume than native tissue, fibrous tissue capsule formation, and rapid resorption over time, all of which can lead to poor esthetic results.12
Circadian rhythm abnormalities in patients with inflammatory bowel disease – association with adipokine profile
Published in Scandinavian Journal of Gastroenterology, 2020
Aleksandra Sobolewska-Włodarczyk, Marcin Włodarczyk, Anna Zielińska, Paweł Siwiński, Maria Wiśniewska-Jarosińska, Anita Gąsiorowska, Jakub Fichna
Until today, there are practically no studies on the relationship between sleep disturbances and the course of IBD, as well as macronutrient absorption in humans. Circadian alignment is crucial for body-weight management, and for metabolic health. Consequently, there is already some evidence for a relationship between the disturbances in the circadian rhythm, body weight and dietary habits. For example, effects of changes in sleep duration during a dietary intervention for body-weight loss were assessed by Nedeltcheva and Scheer [14]. They showed that sleep restriction to 5.5 h compared with 8.5 h sleep compromised the efficacy of a dietary intervention for weight loss. Moreover, the combination of energy and sleep restriction in overweight adults resulted in decreased loss of fat and considerably increased loss of fat-free body mass. These results suggest that sleep plays an important role in the preservation of human fat-free body mass during periods of reduced energy intake. Chaput et al. [15] observed that short duration sleepers who maintained their short sleep duration habits experienced a greater increase in BMI and fat mass over a 6-year follow-up period compared with short-duration sleepers who increased their sleep duration, suggesting that shifting sleep duration from a short length to a healthier length is associated with lower adiposity gain. Moreover, they showed that both sleep duration and sleep quality were significantly related to fat mass loss during dietary interventions in overweight and obese adults. Despite these significant correlations it is not possible to determine any direction of causation.
Effectiveness of the combination of fat grafting and injection on radiation ulcer healing
Published in Journal of Plastic Surgery and Hand Surgery, 2020
Michiko Fukuba, Hiroshi Uozaki, Yuzo Komuro
The effects of fat grafting on radiation-induced skin damage have been reported by many authors and include the attenuation of radiation-induced fibrosis [1] and the alleviation of skin damage [2,3]. Fat tissue contains adipose-derived stem cells (ASCs), which are reported to secrete multiple cytokines, including angiogenic and antiapoptotic factors [4]. Fat grafts can deliver these substances to damaged tissue to improve skin quality following irradiation. The most commonly used fat-grafting technique is the injection method. While a few studies have examined the topical application of stem cells to chronic ulcers [5], none have investigated the application of purified fat grafts to the surfaces of radiation-induced ulcers. We hypothesized that the application of purified fat grafts directly onto radiation-induced ulcer surfaces might have a curative effect via facilitation of the direct contact between the growth factors released from fat tissue and the surfaces of the ulcers. In most of the previous studies of fat grafting, human fat was used as a graft material in immunocompromised animals; however, these conditions do not match with those found in the clinical setting. In the present study, we used a model involving fat from inbred rats that was designed to reproduce clinical conditions and obtain more clinically relevant results, with a specific aim to investigate whether the application of fat grafts to the surfaces of ulcers would be effective at promoting the epithelization of radiation-induced ulcers.