Behavioral temperature regulation in the obese Zucker rat.

The behavioral thermoregulatory capability of lean (Fa/?) and obese (fa/fa) Zucker rats was investigated in an operant conditioning apparatus. Obese rats exposed to –9°C leverpressed for heat significantly more than lean rats, and consequently received more exogenous heat. Despite this increased heat intake, obese and lean animals demonstrated equivalent increases in core temperature. These results suggest that the obese (fa/fa) Zucker rat is not acting on a lowered thermoregulatory set point and is capable of behaviorally thermoregulating to compensate for poor heat absorption and/or a defect in metabolic heat production. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effect of nutrition on combined hyperlipidemia

Academic education for nursing has made a major impact on the development of nursing science, on the quality of nursing practice, and on the image of nursing. This was possible because of the close cooperation between education and nurses working in the various health services. Examples from several countries illustrate the process and outcomes of such mutual collaboration.     

Circadian rhythms in the Zucker obese rat: assessment and intervention

The proximate determinants of fertility framework, developed in its current form by Bongaarts, has been used extensively by researchers for the past 20 years. Since the initial framework was developed, a wealth of new survey data on the proximate determinants has become available. This article reviews the new data and past experiences and suggests modifications to the framework that would take advantage of this experience. The major modifications suggested are (1) the use of sexual activity rather than marriage to indicate exposure to pregnancy; (2) a revision of the sterility index to measure infecundity from all causes; (3) a revised index of contraception that accounts for the fact that users of sterilization may become infecund before age 49; and (4) a revised definition and estimate of total fecundity.     

Role of nerve growth factor in the development of rat sympathetic neurons in vitro. III. Effect on acetylcholine production

The effect of nerve growth factor (NGF) on the development of cholinergic sympathetic neurons was studied in cultures grown either on monolayers of dissociated rat heart cells or in medium conditioned by them. In the presence of rat heart cells the absolute requirement of neurons for exogenous NGF was partially spared. The ability of heart cells to support neuronal survival was due at least in part to production of a diffusable NGF-like substance into the medium. Although some neurons survived on the heart cell monolayer without added NGF, increased levels of exogenous NGF increased neuronal survival until saturation was achieved at 0.5 microgram/ml 7S NGF. The ability of neurons to produce acetylcholine (ACh) from choline was also dependent on the level of exogenous NGF. In mixed neuron-heart cell cultures, NGF increased both ACh and catecholamine (CA) production per neuron to the same extent; saturation occurred at 1 microgram/ml 7S NGF. As cholinergic neurons developed in culture, they became less dependent on NGF for survival and ACh production, but even in older cultures approximately 40% of the neurons died when NGF was withdrawn. Thus, NGF is as necessary for survival, growth, and differentiation of sympathetic neurons when the neurons express cholinergic functions as when the neurons express adrenergic functions (4, 5).     

Effect of chronic growth hormone administration on diabetic nephropathy in the rat

Indirect data exist which implicate elevated growth hormone (GH) as a factor in the development of diabetic nephropathy. The administration of somatostatin (SRIH) has been shown to reverse many of the changes found in early diabetic nephropathy; however, it is unknown whether SRIH causes these effects by the suppression of GH or by other unspecified factors. To study directly the possible effect of excess GH in the development of diabetic nephropathy, either ovine growth hormone (0.2 mg oGH) or diluent buffer was administered IM daily for 19 weeks to diabetic rats and to controls. Severity of nephropathy was assessed by 24 hour urine albumin excretion (UAE), relative kidney weight, and kidney histology. Results showed that diabetic rats overall had elevated UAE and kidney weight vs non-diabetic rats (46.2 +/- 8.6 vs 5.4 +/- 1.3 mg per day and 5.7 +/- 0.2 vs 2.7 +/- 0.1 mg per g of body weight, respectively, p < 0.001). However, no differences were detected between diabetic rats treated with GH compared to control diabetic rats. Additionally, diabetic rats had histopathologic changes consistent with early diabetic nephropathy, but no difference in severity scores was found between diabetic groups. These data provide evidence against GH as an etiologic factor in the development of diabetic nephropathy and it is speculated by the authors that SRIH exerts its protective renal effects in diabetes by mechanisms other than GH suppression.     

Effect of aluminium on the development of hyperparathyroidism and bone disease in the azotaemic rat

Natural (molybdenite) and synthesized molybdenum disulfide crystals have been studied by high-resolution transmission electron microscopy. The image simulation demonstrates that the [0001] and [0110] HRTEM images of hexagonal and rhombohedral MoS2 crystals hardly disclose their stacking sequences, and that the [2110] images can distinguish the Mo and S columns along the incident electron beam and enable one to determine not only the crystal structure but also the fault structure. Observed [0001] images of cleaved molybdenite and synthesized MoS2 crystals, however, reveal the strain field around partial dislocations limiting an extended dislocation. A cross-sectional image of a single molecular (S-Mo-S) layer cleaved from molybdenite has been observed. Synthesized MoS2 flakes which were prepared by grinding have been found to be rhombohedral crystals containing many stacking faults caused by glides between S/S layers.     

Effects of the glucocorticoid agonist, RU28362, and the antagonist RU486 on lung phosphatidylcholine and antioxidant enzyme development in the genetically obese Zucker rat

The biochemical maturation of the lung in late gestation and in the young animal is regulated by glucocorticoids. The present study was aimed at dissociating the different glucocorticoid receptor sites involved in these regulatory functions. The obese Zucker rat was selected as a model for this study as it exhibits hypersensitivity to glucocorticoid hormone action by virtue of its elevated receptor numbers and activity. Two synthetic steroid analogues were administered to obese animals; RU28362, a specific type II receptor agonist, and the type II antagonist RU486. RU28362 promoted a strong catabolic effect, which was associated with reduced food intake and the abolition of growth in the rats. The agonist, RU28362, attenuated developmental increases in antioxidant enzyme activities, and altered the growth of the tissue. At the age studied, development of the lung phosphatidylcholine (PC) system was almost complete, but RU28362 increased disaturated PC 16:0/16:0 concentrations by almost 2-fold, and altered the molecular composition of total pulmonary PC. RU486 attenuated the growth of the rats and reduced their food intake. Treatment with the type II antagonist attenuated lung growth and increased the activities of pulmonary copper zinc (Cu/Zn) and manganese (Mn) superoxide dismutases. RU486 had no effect on lung PC concentrations and molecular composition. The data suggest a role for type I glucocorticoid receptors in the regulation of the antioxidant enzyme system in the lung, as type II antagonism will channel endogenous glucocorticoid binding to the type I site. Type II receptor binding would appear to play a role in regulating the lung PC content.     

Combined effect of obesity and aging on feeding-induced monoamine release in the rostromedial hypothalamus of the Zucker rat

OBJECTIVE: The obesity of the Zucker rat is associated with numerous metabolic and neurochemical disturbances involving the central transmitters regulating feeding behaviour. Among them, the release of satiety-related monoamines from the median hypothalamus in response to a meal is enhanced in obese, as compared to normal, rats as though larger amounts of these amines were necessary to bring about satiety in obese rats. Besides, the obese Zucker rat has often been described as shorter-living than its lean congener. One of the reasons for the shorter longevity of the obese rat was investigated in this study: it could be an aggravation of its obesity-related central disturbances with age. METHODS: We assessed the response to a meal of the hypothalamic monoamines, dopamine and serotonin, in young (four month old) and old (twelve month old) lean (Fa-Fa) and obese (fa-fa) Zucker rats. The in vivo technique of microdialysis was used to combine behavioural recordings and continuous neurochemical assays. RESULTS: The exacerbation of monoamine release observed in young obese rats in response to a meal was no longer found in old obese rats. Serotonin increase during a meal weakened with aging, especially in obese rats. Dopamine (DA) response to a meal was completely reversed in old obese rats, with a decrease instead of the increase observed in the three other groups. CONCLUSION: The decrease of monoaminergic response to a meal with age is apparently the opposite to the enhanced release related to obesity. However, this does not correspond to an amelioration of the hyperphagia of the obese rats with age, as we could observe in parallel behavioural experiments, but rather to a decrease in neurotransmitter metabolism and thus in neuronal functioning.     

Effect of visual deprivation on development of depth perception in the rat.

Compared the behavior of light- and dark-reared Long-Evans hooded rats (N = 1,786) at 20-160 days of age in 3 experiments using a visual cliff apparatus in which the depth of the deep side could be varied. Differential depth thresholds obtained revealed no significant difference at 20 days in perceptual ability due to rearing condition. Both groups showed improvement in depth perception over the next 40-60 days. Dark-reared Ss did not improve at the same rate nor acquire the same degree of discriminative ability as did light-reared Ss. The performance of light-reared Ss leveled off after 100 days, but dark-reared Ss' ability deteriorated. Results are discussed in terms of further specification of the effects of visual deprivation on perceptual capacities. (32 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Suction lipectomy of the ankle area

This article discusses the basic concepts of the aesthetics of the ankle area, emphasizing the lower limb's proportions, and looking for the greatest proportional fineness in this area. The normal ankle is schematized as if it were a rhomboid prism whose major axis is anteroposterior, and circumferential liposuction is discussed in order to avoid reproduction of the same ankle's lipodystrophic shapes. To do so, the roundness of the ankle is divided as if it consisted of the rectangular faces of a rhomboid prism to get the anatomic and aesthetic shapes of this area. The article also discusses the details of the anesthesic infiltration, the surgical technique, and ways to avoid any damage in the noble structures when liposuction is performed in the ankle area. This technique may be applied when the orthostatic axis of the lower limbs is deflected; it can be optically corrected in the leg or aligned through exaggerated liposuction of the convex lipodystrophic areas.     

Investigation of oxidant stress and vasodepression to glyceryl trinitrate in the obese Zucker rat in vivo

OBJECTIVE: To describe risk factors and explore mechanisms of ischemic strokes after general surgery. BACKGROUND: Strokes follow general surgery in about 0.08% to 2.9% of cases. Patients with previous cerebrovascular disease, atrial fibrillation, hypertension, advanced age, or atherosclerosis were found to have an increased risk. Knowledge of factors involved may guide physicians in determining the overall risk of surgery. METHODS: This case-control study was performed in a referral center. A total of 61 patients identified through a computerized database with ischemic strokes after surgical procedures-excluding heart, brain, vessels, or neck-between July 1986 and July 1996 were studied. Procedures included 11 urogenital, 16 gastrointestinal, 17 orthopedic, 12 pulmonary, and 5 other. A total of 122 randomly selected controls were matched for age, sex, procedure, and year of procedure. Main outcome measures included arterial territory, timing, risk factors, and perioperative events. Differences were expressed as adjusted odds ratios (AOR) with 95% confidence limits (CL), using multivariate conditional logistic analyses for matched case-control design. RESULTS: Arterial territory included 37 middle cerebral artery, 11 posterior circulation, 7 borderzone, and 6 multiple. Median procedure to stroke interval was 2 days (range, 0 to 16); 10 patients had intraoperative strokes. Three major risk factors emerged: previous cerebrovascular disease (AOR 12.57, 95% CL 2.14/73.70), chronic obstructive pulmonary disease (COPD) (7.51, 1.87/30.12), and peripheral vascular disease (PVD) (5.35, 1.25/22.94). After adding stroke-related factors, PVD (14.70, 2.01/107.71) and COPD (10.04, 1.90/53.14) remained the strongest variables; blood pressure (1.05, 1.01/1.10) and urea (1.04, 1.01/1.07) contributed slightly. Hypotension did not contribute. Four patients (6.6%) and no controls had diffuse intravascular coagulation (p = 0.01). Four stroke patients had myocardial infarction (6.6% versus 0%; p = 0.01). CONCLUSIONS: Ischemic strokes after general surgery most commonly occur after an asymptomatic interval. Previous cerebrovascular disease, COPD, and PVD greatly increase the risk. Hypotension rarely accounts for postoperative strokes. Major comorbidity of the patient at risk seems more important than complicating events during surgery.     

Effect of yohimbine on nerve growth factor mRNA and protein levels in rat hippocampus

Activation of noradrenergic receptors has been shown to increase expression of nerve growth factor (NGF) gene in brain cells in vitro. The present studies were undertaken to determine if this stimulation was effective in vivo as well. Rats were administered the norepinephrine-releasing drug, yohimbine (YOH), and had their hippocampi assayed for NGF mRNA and protein at various times after the injection. It was found that yohimbine caused a 3-fold increase of NGF mRNA levels at 24 h. Protein levels, however, were unaltered at this time. Thus norepinephrine release in vivo appears to be sufficient for increasing mRNA level but not for translation to protein.     

Leptin receptor of Zucker fatty rat performs reduced signal transduction

Arthroscopy of the first carpometacarpal joint has been developed as a reliable surgical procedure offering an opportunity for direct evaluation of the joint's intra-articular status, with minimal morbidity to the joint capsule. The procedure uses a 1.9-mm short barrel arthroscope with standard supportive electronic equipment. After adequate anesthesia is established, approximately 5 lb. of longitudinal traction is applied to the thumb. Arthroscopic portals are located on the radial side of the abductor pollicis longus tendon (1-R portal) and the ulnar side of the extensor pollicis brevis tendon (1-U portal). Care must be exercised in establishing these portals so that injury to the radial artery and branches of the superficial radial nerve can be avoided.     

Effect of subchronic metformin treatment on macronutrient selection in genetically obese Zucker rats

Metformin has been particularly recommended to be used in obese type 2 diabetic patients because of its weight decreasing and serum lipid profile normalizing effects. In the present study the effects of subchronic metformin treatment on macronutrient selection, weight gain and plasma insulin and glucose were investigated in 20 genetically obese male Zucker rats which were maintained on a free-feeding self-selection paradigm with three pure macronutrient diets of carbohydrate, fat and protein. Half of the rats were given metformin hydrochloride 320 mg/kg/day up to 18 days in drinking water. The other half of the animals received normal drinking water as a control. Metformin treatment significantly reduced 24 hr carbohydrate (P < 0.01), fat (P < 0.001) and protein (P < 0.01) intake. The proportion of fat of the total consumed energy was significantly increased by metformin (P < 0.01) while the proportion of protein was decreased (P < 0.05). In hunger stimulated feeding experiment metformin decreased selectively protein intake (P < 0.01). Changes in macronutrient selection were associated with reduced body weight gain in metformin treated rats (P < 0.001). Metformin markedly reduced the hyperinsulinaemia (P < 0.01) and plasma glucose levels (P < 0.05), which suggests improved glucose tolerance after metformin treatment. It is concluded that subchronic metformin treatment can modify the composition of energy intake in a macronutrient selective manner.