Dietary fat, ketosis, and seizure resistance in rats on the ketogenic diet

PURPOSE: Fat is the major component of the ketogenic diet (KD), yet no studies have examined whether the type of fat used in the diet can be optimized to provide additional benefits. The purpose of the present experiments was to compare the efficiency of different fats in inducing ketosis and affording seizure resistance. METHODS: The effects of KDs that incorporate lard, butter, medium-chain triglycerides (MCT), or flaxseed oil or a mixture of the latter three fats were examined in rats fed KD for up to 98 days. The maximal electroshock (MES) or pentylenetetrazole (PTZ) threshold tests were used to assess seizure susceptibility in two separate experiments. RESULTS: The rank order of induced ketosis was MCT > mixture > or = flaxseed oil > or = lard = butter > or = control. MES failed to reveal anticonvulsant effects, but the PTZ test indicated that up to 50% of rats fed the KD were seizure protected (p < 0.05). The measures of seizure protection, seizure incidence and score, did not correlate, however, with the level of ketosis in the range of 0. 7-5.2 mmol/L for beta-hydroxybutyrate. In the long-term study, flaxseed oil KD maintained stable ketosis throughout 98 days, whereas ketones declined with lard and butter KD to the control level. CONCLUSIONS: Seizure protection with the versions of the KD did not improve with the higher level of ketosis. The focus of the KD improvement, therefore, is not the achievement of higher ketosis per se but rather designing a diet that provides steady ketosis, exploits advantages of certain fats for neurological development or seizure protection via a nonketogenic mechanism, and is nutritionally balanced.     

Dose-dependent autonomic dysfunction in chronic L-NAME-hypertensive diabetic rats

This study investigated the effects of varying doses of L-NAME on arterial pressure (AP), baroreflex control, and heart rate (HR)/AP variability in the STZ-diabetic rat. Fifty-two male Wistar rats were injected with 50 mg/kg IV STZ (diabetes, D, n = 24) or citrate (controls, C, n = 28) 30 days before recordings. After 16 days, they received 14 days of oral L-NAME, 10 (H10) or 30 (H30) mg/kg, or water. Catheters were implanted into the femoral artery and vein (PE-10) for measurements in conscious rats; recorded data were analyzed on a beat-to-beat basis. Mean AP was higher in CH30 versus C and in DH10 and DH30 versus D rats. Reflex tachycardia was blunted in CH30 and DH30 rats (b = -1.81, -1.41, -0.48 in C, CH10, and CH30, respectively, P < 0.05 and b = -1.45, -1.19, -0.28 in D, DH10, and DH30, respectively, P < 0.05). Although HR and AP variability were reduced in CH30 and DH30 rats versus C and D rats, the DH30 rat had more accentuated dysfunction. All doses of L-NAME produced similar AP responses in experimental versus control groups, independent of the disease state (diabetes). Thus, autonomic dysfunction is more related to the L-NAME dose used and to the association of diabetes and hypertension than to AP values.     

Antihypertensive response to prolonged tempol in the spontaneously hypertensive rat

INTRODUCTION: Tempol is a permeant nitroxide superoxide dismutase (SOD) mimetic that lowers mean arterial pressure (MAP) in spontaneously hypertensive rats (SHRs). We investigated the hypothesis that the antihypertensive response entails a negative salt balance, blunting of plasma renin activity (PRA), endothelin-1 (ET-1), or catecholamines or correction of oxidative stress as indexed by 8-isoprostane prostaglandin F(2alpha) (PGF(2alpha)) (8-Iso). METHODS: Groups (N= 6 to 8) of SHRs were infused for 2 weeks with vehicle or tempol (200 nmol/kg/min) or given tempol (2 mmol/L) in drinking water. RESULTS: Tempol infusion reduced the MAP of anesthetized SHRs (150 +/- 5 vs. 126 +/- 6 mm Hg) (P < 0.005). Oral tempol did not change the heart rate but reduced the MAP of conscious SHRs (-23 +/- 6 mm Hg) (P < 0.01) but not Wistar-Kyoto (WKY) rats. Tempol infusion increased the PRA (2.2 +/- 0.2 vs. 5.0 +/- 0.9 ng/mL/hour) (P < 0.005), did not change excretion of nitric oxide (NO) [NO(2)+ NO(3) (NOx)], ET-1, or catecholamines but reduced excretion of 8-Iso (13.2 +/- 1.4 vs. 9.6 +/- 0.9 ng/24 hours; P < 0.01). Cumulative Na(+) balance and gain in body weight were unaltered by tempol infusion. Tempol prevented a rise in MAP with high salt intake. CONCLUSION: Tempol corrects hypertension without a compensatory sympathoadrenal activation or salt retention. The response is independent of nitric oxide, endothelin, or catecholamines and occurs despite increased PRA. It is accompanied by a reduction in oxidative stress and is maintained during increased salt intake.     

The laparoscopic management of intersex patients: the preferred approach

In the world's largest series of patients with intersex treated by laparoscopy, authors from Sao Paulo found that this technique allowed easy identification and removal of gonads. They also found that other organs could be removed and genitoplasty performed. OBJECTIVE: To present possibly the largest series of the use of laparoscopy for treating intersex patients. PATIENTS AND METHODS: Fifty intersex patients (34 with male and two with female pseudohermaphroditism, nine with gonadal dysgenesis, four with true hermaphroditism, and one with complex hypospadias), aged 0.5-46 years (mean 18.3), underwent laparoscopy to remove gonads and/or ductal structures incompatible with the social gender, or for gonadal tumour or a potential risk for malignancy. When necessary, genitoplasty was performed concomitantly. RESULTS: At the laparoscopic evaluation, 10 gonads of six patients were absent, while four were identified as 'vanishing'; 72 gonads (46 dysgenetic, 17 normal testes, one normal ovary, one ovotestis, seven gonadoblastomas or dysgerminomas) were removed; two ovotestes were replaced in the scrotum after removing the ovarian segment, as was one normal testis. Twelve patients with a urogenital sinus had its vaginal component removed, 11 including a hysterectomy. Three of these patients had a combined perineal approach to complete its removal, together with masculinizing genitoplasty. There were no intraoperative complications or conversions; two patients had complications after surgery. CONCLUSIONS: Laparoscopy allows the straightforward identification and removal of gonads. All abnormal ductal structures must be removed, as this increases the chance of resecting unidentified gonads. Removing the uterus and vaginal component of the urogenital sinus in patients with male social sex is feasible, with low morbidity. Genitoplasty, according to the social sex, can be performed in the same procedure.     

Characterization of the spontaneous and gripping-induced immobility episodes on taiep rats

In 1989, we described a new autosomic-recessive myelin-mutant rat that develops a progressive motor syndrome characterized by tremor, ataxia, immobility episodes (IEs), epilepsy, and paralysis. taiep is the acronym of these symptoms. The rat developed a hypomyelination, followed by demyelination. At an age of 7-8 months, taiep rats developed IEs, characterized electroencephalographically by REM sleep-like cortical activity. In our study, we analyzed the ontogeny of gripping-induced IEs between 5 and 18 months, their dependence to light-dark changes, sexual dimorphism, and susceptibility to mild stress. Our results showed that IEs start at an age of 6.5 months, with a peak frequency between 8.5 and 9.5 months. IEs have two peaks, one in the morning (0800-1000 h) and a second peak in the middle of the night (2300-0100 h). Spontaneous IEs showed an even distribution with a mean of 3 IEs every 2 h. IEs are sexually dimorphic being more common in male rats. The IEs can be induced by gripping the rat by the tail or the thorax, but most of the IEs were produced by gripping the tail. Mild stress produced by i.p. injection of physiological saline significantly decreased IEs.These results suggested that IEs are dependent on several biological variables, which are caused by hypomyelination, followed by demyelization, which causes alterations in the brainstem and hypothalamic mechanisms responsible for the sleep-wake cycle regulation, producing emergence of REM sleep-like behavior during awake periods.     

Aneural culture of rat myoblasts for myocardial transplant

Due to the peculiar characteristics of skeletal muscle, myoblast transplants have emerged as a therapy for cardiomyopathy, particularly after myocardial infarction. The objectives of this study were to define the mean time of cultivation necessary to obtain a cellular concentration of 10(6) to expand the mass for transplant, and to identify the proliferation phase of myoblasts. Ten myoblast cultures were performed using newborn Wistar rats. The isolation method used enzymatic dissociation in culture medium (HAM-F12 and 199) supplement with basic-fibroblast growth factor (b-FGF) and insulin growth factor (IGF-I). The mean cultivation time to obtain the desired concentration of 10(6) was 7 days, with expansion of up to 10(8)/g. When b-FGF was used, the cellular yield was approximately 10(7), with IGF-I the cellular yield was approximately 10(8), independent of the medium. We concluded that IGF-I is the better option for mass cellular expansion of myoblasts for application in myocardial transplants.     

Involvement of bradykinin, cytokines, sympathetic amines and prostaglandins in formalin-induced orofacial nociception in rats

1. This study characterises some of the mechanisms and mediators involved in the orofacial nociception triggered by injection of formalin into the upper lip of the rat, by assessing the influence of various treatments on behavioural nociceptive responses (duration of facial rubbing) elicited either by a low subthreshold (i.e. non-nociceptive; 0.63%) or a higher concentration of the algogen (2.5%). 2. The kininase II inhibitor captopril (5 mg kg(-1), s.c.) and prostaglandin(PG) E(2) (100 ng lip(-1)) potentiated both phases of the response to 0.63% formalin, whereas tumour necrosis factor (TNF alpha; 5 pg lip(-1)), interleukin(IL)-1 beta (0.5 pg lip(-1)), IL-6 (2 ng lip(-1)) and IL-8 (200 pg lip(-1)), or the indirectly acting sympathomimetic drug tyramine (200 microg lip(-1)), each augmented only the second phase of nociception. 3. Conversely, both phases of nociception induced by 2.5% formalin were inhibited by the bradykinin (BK) B(2) receptor antagonist HOE140 (5 microg lip(-1)) or the selective beta(1)-adrenoceptor antagonist atenolol (100 microg lip(-1)). However, the BK B(1) receptor antagonist des-Arg(9)-Leu(8)-BK (1 and 2 microg lip(-1)), antibody and/or antiserum against each of the cytokines, the adrenergic neurone blocker guanethidine (30 mg kg(-1) day(-1), s.c., for 3 days) and the cyclooxygenase(COX)-2 inhibitor celecoxib (50 and 200 microg lip(-1), s.c.; or 1 and 3 mg kg(-1), i.p.) reduced only the second phase of the response. The nonselective COX inhibitor indomethacin and the 5-lipoxygenase activating protein inhibitor MK886 did not change formalin-induced nociception. 4. Our results indicate that BK, TNF-alpha, IL-1 beta, IL-6, IL-8, sympathetic amines and PGs (but not leukotrienes) contribute significantly to formalin-induced orofacial nociception in the rat and the response seems to be more susceptible to inhibition by B(2) receptor antagonist and selective COX-2 inhibitor than by B(1) receptor antagonist or nonselective COX inhibitor.