EVOLUTION DE L''INCORPORATION IN VIVO DE L''ACIDE [14C]OROTIQUE DANS L''ARN ET L''ADN DU CERVELET DE JEUNES RATS HYPO- ET HYPERTHYROIDIENS: EFFETS COMPARATIFS DE L''HYPO- ET L''HYPERTHYROIDIE SUR LES MULTIPLICATIONS CELLULAIRES

The change in the body and cerebellar weights, together with the quantity of RNA, DNA and proteins in the cerebellum were studied for the first 10 days and on the 12th, 14th, and 17th days of postnatal life in normal, hypo- and hyperthyroid rats. In the normal animals: (1) The average cellular protein content decreases from the first to the second day, increases to a maximum at 4 days, then decreases. (2) The specific radioactivity of the RNA, 14 h after an intravenous injection of [6-¹⁴C]orotic acid, varies distinctly from birth to 9 days and reaches two maxima at 4 and 6 days. After 9 days it decreases markedly. (3) Mitotic activity (number of replicating cells) increases, reaches a maximum at 9 days, then decreases. (4) The specific radioactivity of the DNA (used as a measure of the percentage of the cellular population in division) reaches a maximum at 6 days. (5) Mitotic efficiency (number of replicating cells in mitotic activity) decreases from 2 to 7 days, and subsequently increases. In the hypothyroid animals: (1) The average cellular protein content increases from the first to the second day and then decreases. (2) The specific radioactivity of the RNA, always significantly higher than that of normal animals, varies from birth to 9 days, reaches two maxima at 4 and 6 days, then decreases after 9 days. (3) Mitotic activity, always significantly lower than that of normal animals, increases from birth, reaches a maximum at 9 days, then decreases. (4) The specific radioactivity of the DNA reaches a maximum at 6 days and the mitotic efficiency a minimum at 7 days. Neither are significantly different from that of normal animals. In the hyperthyroid animals: (1) The average cellular protein content, is maximal at 2 days, then decreases. (2) The specific radioactivity of the RNA, always significantly lower from that of normal animals, decreases from birth. (3) Mitotic activity is similar to that of normal animals, increases from birth up to 6 days, then decreases. (4) The specific radioactivity of the DNA increases from birth up to 5 days, then decreases. It is significantly lower than that of normal animals. (5) Mitotic efficiency is significantly higher than that of normal animals. In the different groups, the maximum of the average cell size, always precedes the maximum of the cellular division. In the hypothyroid animals, the rate of cell death is higher than that of normal animals, and the average cell size is higher during the first fourteen days. In the hyperthyroid animals, the rate of cell death is lower than that of normal animals, and the average cell size is higher at 14 and 17 days.     

Influence of a CIDR prior to bull breeding on pregnancy rates and subsequent calving distribution

We determined whether insertion of a CIDR for 7 days prior to the breeding season enhanced pregnancy rates and altered the date of conception in suckled beef cows mated naturally. Suckled beef cows (n=2033) from 15 locations were randomly assigned to one of two treatments: (1) cows received a CIDR 7 days prior to the breeding season for 7 days (CIDR; n=999); (2) cows received no treatment (Control; n=1034). On the first day of the breeding season bulls were introduced to herds at a rate of 15-25 cows per yearling bull or 20-30 cows per mature bull. Pregnancy status and the date of conception were determined via transrectal ultrasonography at 56 and 120 days after initiation of the breeding season. Overall pregnancy rates ranged from 59.3 to 98.9% among the 15 locations. The percentage of cows becoming pregnant during the first 30 days of the breeding season was similar between CIDR (68.2%) and Control (66.7%) cows, and overall pregnancy rates were similar between CIDR (88.9%) and Control (88.6%) cows. The average day of conception after initiation of the breeding season was shorter (P<0.01) for CIDR (20.1+/-0.8 days) compared to Control cows (23.2+/-0.8 days). Of cows conceiving during the breeding season, more (P<0.05) CIDR cows (35.9%) conceived during the first 10 days of the breeding season than Control cows (30.8%). Neither body condition score and nor parity affected pregnancy rates or days to conception, whereas pregnancy rates and days to conception were affected (P<0.01) by location and days postpartum. Days to conception were greater for cows that calved within 40 days (31.6+/-1.2 days) of initiation of the breeding season compared to cows calving between 40 and 50 days (25.3+/-1.2 days) prior to initiation of the breeding season, which were greater than those cows calving between 50-60 days (20.0+/-0.8 days) and 60-70 days (21.3+/-1.0 days) prior to initiation of the breeding season. Cows calving greater than 70 days (17.3+/-1.5 days) from initiation of the breeding season had the shortest interval to conception. We concluded that insertion of a CIDR prior to the breeding season failed to increase overall pregnancy rates, but did influence the average day of conception.     

Effects of photoperiod and social variables on reproduction and growth in the male musk shrew (Suncus murinus)

In Exp. 1, the time course for the photoperiodic response in juvenile male musk shrews was examined by exposing animals to short (10L:14D) or long (14L:10D or 18L:6D) daylengths for 10, 20, 40 or 56 days. When compared with the response of animals maintained in long days, those exposed to short days showed an inhibition of reproductive maturation by 40 days of treatment. In Exp. 2, the combined effects of photoperiod and social cues were investigated in juvenile males that were either housed in short days (with or without a female) or in long days (with or without a female) for 40 days. The short photoperiod was generally inhibitory to sexual maturation, while the presence of an adult female was generally stimulatory, i.e. animals living with a female in long days had the greatest level of sexual maturity, while those living alone in short days had the lowest level of maturity. Animals that received opposing signals, i.e. short days in the presence of a female, had an intermediate response which was equivalent to the response seen in males living alone in long days. These results suggest that the presence of a female can partly reverse inhibitory effects of short days. In Exp. 3, the effects of photoperiod and social cues on the reproductive physiology of the adult male (same design as in Exp. 2) were investigated. The results show that the adult male musk shrew is responsive to both photoperiodic and social cues, in a manner similar to that of juvenile animals.(ABSTRACT TRUNCATED AT 250 WORDS)     

Intrauterine infusion of prostaglandin E2 and subsequent luteal function in cattle.

The objective was to evaluate the effect of intrauterine infusion of prostaglandin E2 (PGE2) on luteal function in cattle. Heifers and cows were randomly assigned after two normal estrous cycles to either PGE2 or control treatment groups. Females in Treatment A were infused with 1 mg of PGE2 once daily into the uterine horn ipsilateral to the corpus luteum between days 7-10 of the estrous cycle with a 0.25 ml plastic semen straw and an artificial insemination pipette. Females in Treatment B were similarly infused with 1 mg of PGE2 once daily in 20 ml of a carrier vehicle via a catheter on days 10 and 11 of the estrous cycle. Control animals were infused with the carrier vehicle using either a semen straw (Treatment C) or via a catheter (Treatment D) on the same days of the estrous cycle. Blood samples were collected daily to monitor plasma progesterone concentrations during the treatment period. Females infused with PGE2 on days 7-10 of the estrous cycle returned to estrus in a mean of 23.5 days (range 22-25 days) and were similar (P > 0.05) to those infused on days 10 and 11 which returned to estrus in 23.5 days (range 22-25 days). Animals similarly infused with carrier vehicle on the same days of the estrous cycle returned to standing estrus in 20.2 days (range 17-23 days). Plasma progesterone concentrations indicated an extended period of elevated progesterone concentrations in PGE2-treated animals compared with control animals. These results indicate that short term administration of PGE2 early in the estrous cycle may result in extended luteal maintenance.     

Regulation of estrus and ovulation in mares with progesterone or progesterone and estradiol biodegradable microspheres with or without PGF2alpha

A single injection of a microsphere preparation, designed to deliver 1.25 gm progesterone and 100 mg estradiol-17beta at a controlled rate, for a duration of 12 to 14 days, produces accurate control of estrus and fertile ovulations in mares. Theatment is followed by PGF(2)alpha injection 14 days after steroid injection. The objectives of the present study were to determine whether estradiol added to the progesterone treatment or PGF(2)alpha administered at the end of the steroid treatment regimen, would improve synchronization of estrus and ovulation. A total of 45 cyclic horse mares was randomly assigned to 1 of 5 treatment groups as follows: Group 1 (control, n=9) sterile microsphere vehicle + sterile PGF(2)alpha vehicle 14 days after treatment with microsphere vehicle; Group 2 (n=9) progesterone and estradiol microspheres + PGF(2)alpha 14 days after treatment with microspheres; Group 3 (n=9) progesterone and estradiol microspheres + PGF(2)alpha vehicle 14 days after treatment with microspheres; Group 4 (n=9) progesterone + PGF(2)alpha 14 days after treatment with microspheres; and Group 5 (n=9) progesterone + PGF(2)alpha vehicle 14 days after treatment with microspheres. Addition of estradiol (P<0.05) or PGF(2)alpha (P<0.05) to the treatment regimen increased synchronization efficary by reducing variation in days to ovulation. All treatments significantly reduced variation in days to estrus compared with that of the controls; however, mares in the progesterone groups had an increased incidence of silent or shortened estrous behavior (<- 2 days) following treatment. Estradiol added to the treatment regimen increased (P<0.05) the number of mares with post treatment estrus > 2 days in duration compared with mares treated with progesterone (78 vs 33%, respectively). Therefore, estradiol and PGF(2)alpha each appear to reduce variation in days to ovulation while estradiol seems to promote better expression of posttreatment estrous behavior.     

Susceptibility dynamics in neonatal BALB/c mice infected with Cryptosporidium parvum.

BALB/c Mice were infected as neonates and at different ages to study the susceptibility dynamics in this animal model to Cryptosporidium parvum. When 4-day-old animals were infected with 10(5) C. parvum oocysts, parasites were detected in the terminal ileum when the mice became 14-25 days old (10-21 days post-infection [PI]). The percentage of animals positive for parasites was 100% up to the age of 19 days (15 days PI) but decreased immediately thereafter until no parasites were detected in 26-day-old (22 days PI) or older mice. Parasite load also decreased in these animals from 184.7 parasites per high power field in 14-day-old animals (10 days PI) to 0.22 in 25-day-old (21 days PI) mice. In a second study, some neonatal mice became resistant to C. parvum when infection was attempted at day-10 of age (day-15 of age at sacrifice). The susceptibility to C. parvum decreased until 14 days of age (19 days of age at sacrifice) when mice could no longer be infected. Parasite load also decreased in infected mice from 235.6 parasites per high power field (9 days of age at sacrifice) to 0.25 (18 days of age at sacrifice).     

Developmental expression of bovine adrenocortical steroid hydroxylases. Regulation of P-450(17 alpha) expression leads to episodic fetal cortisol production

The developmental expression of adrenocortical steroid hydroxylases was studied in bovine fetuses from 40 to 280 days gestational age. The expression of P-450(17 alpha) is first detected at a gestational age of 50 days and reaches a maximum at 60-70 days. The expression of P-450(17 alpha) then declines and is nondetectable at a gestational age of 100 days. P-450(17 alpha) is not expressed again until about 240 days, i.e. shortly before birth (approximately 280 days). P-450scc, P-450c21, P-450(11 beta) and adrenodoxin were present in fetal adrenals throughout gestation. This "on-off-on" pattern of P-450(17 alpha) expression during fetal development was associated with a corresponding episodic production of cortisol. Immunoreactive corticotropin (ACTH) levels in fetal plasma were elevated in small fetuses (corresponding to less than or equal to 100 days) and in near-term fetuses (corresponding to greater than 250 days) compared with those in mid-gestation fetuses. In primary culture, adrenal cells from mid-gestation fetuses contained no detectable P-450(17 alpha) but rapidly responded to ACTH with an increase in P-450(17 alpha) protein and mRNA. The tissue specificity of the developmental patterns is emphasized by the fact that both P-450(17 alpha) and P-450scc were detectable throughout the development of the fetal testes, whereas only P-450scc was detectable in fetal bovine ovary prior to 200 days. Thus, in fetal bovine adrenal it appears that ACTH is the major regulatory factor effecting the intermittent presence of P-450(17 alpha), whereas the presence of the other steroid hydroxylases is either regulated by additional factors or shows a much different sensitivity to ACTH.     

齐口裂腹鱼幼鱼疲劳后游泳特性恢复状况研究

以中国地质公园（神农架）野生动物繁育基地提供的齐口裂腹鱼（Schizothorax prenanti）幼鱼（体长为14.017.5 cm,体重为39.665.6 g）为研究对象,利用自制鱼类游泳特性（Swimming performance）研究装置,运用递增流速法（Stepped velocity test）,研究了鱼类疲劳后20d和40d的游泳特性恢复状况。结果表明:（1）在20d内齐口裂腹鱼临界游泳速度（Critical swimming speed,Ucrit）相比于初次测试（20d前）有所降低,20d内的恢复状况较差;而在40d后,临界游泳速度已经基本恢复到最初状况,40d内的恢复状况较好。（2）疲劳后鱼类游泳效率显著下降,并且在40d后无法恢复正常。虽然40d后速度指数低于20d后速度指数,40d后游泳效率高于20d后游泳效率,但是相对于初次测试,40d后游泳效率恢复效果并不明显。（3）齐口裂腹鱼在疲劳后40d内,恢复能力（Recovery capability）无法恢复到正常状况,但由于3次测试中疲劳后过量耗氧（Excess post-exercise oxygen cost,EPOC） 波动并不大,说明疲劳对其恢复能力影响并不大。（4）20d后和40d后无氧呼吸时间均较第一次测试时提前,说明疲劳损伤对其有氧呼吸能力产生了持续影响。（5）疲劳对鱼类生态行为（Ecological behavior）影响不明显。研究有利于为鱼道建设提供基础资料,对生物多样性保护具有深远意义。       

Influence of hypergravity on hypothalamic vasopressin and oxytocin neurons in rats

This study was aimed to evaluate the reaction of the vasopressin (VP) and oxytocin (OT) neurons of the supraoptic nucleus (SON) in rats to single or repeated hypergravity (HG). Special attention was paid to the tyrosine hydroxylase (TH) expression in VP neurons as a marker of the neuron activation. Rats were revolved in a centrifuge with overloading 2G for 5 days or 34 days as well as for 34 days plus 5 days with an interval of 39 days between two rotations. Control rats were kept in a centrifuge room. Radioimmununoassay, quantitative and semi-quantitative immunocytochemistry and in situ hybridization were used to evaluate: a) VP concentration in the pituitary posterior lobe (PL) and in plasma; b) the number of VP-, OT- and TH-immunoreactive neurons in the SON; c) the optic density of VP-, OT- and TH-immunoreactive materials in cell bodies (SON) and distal axons (PL), d) the optic density of VP and OT mRNAs signals (S35) in the whole SON on microfilms. According to our data, VP neurons were strongly activated during HG (5 days or 34 days) that was manifested in the functional hypertrophy of the neurons, greatly increased concentrations of VP mRNA in the SON and VP in plasma, the onset of the TH expression. The neurons showed initially (5 days) the functional insufficiency (VP release > VP synthesis) followed by their adaptation (subsequent 29 days) to the increased need in VP (VP release < VP synthesis). No reaction of VP neurons was observed to repeated HG. In contrast to VP neurons, OT neurons did not react to short-term HG or showed functional depression after the long-term treatment.     

Chronic leptin infusion advances, and immunoneutralization of leptin postpones puberty onset in normally fed and feed restricted female rats

Does leptin play a vital role in initiating puberty in female rats and can it overrule a nutrionally imposed (i.e. a 30% feed restriction, FR) delay in puberty onset? Prepubertal female rats were chronically infused for 14 days with leptin (icv or sc) or leptin-antiserum (icv) while puberty onset was monitored by means of scoring the moment of vaginal opening (VO). Median VO age was higher (35 days versus 27 days) in FR animals but leptin levels at VO were significantly decreased (1.44 +/- 0.17 ng/ml versus 2.79 +/- 0.31 ng/ml). Centrally (icv) and peripherally (sc) infused leptin (1 microg/day) advanced VO age compared to FR controls (30 days versus 35 days and 31 days versus 41 days, respectively). Congruently, centrally (icv) administered leptin-antiserum (0.6 microg/day) delayed puberty onset. In normally fed rats median VO age was only marginally advanced (26 days versus 27 days) but only if leptin was applied centrally. The effects of FR on puberty onset are counteracted or even normalized by the infusion of leptin, whereas immunoneutralization of central leptin postpones puberty onset. We therefore conclude that central leptin is crucial for initiating puberty in female rats.     

Changes in the estrous cycle and number of ovulated and fertilized ova in aging female IVCS mice

IV CS mice (ddN origin) aged 90 days (control) and 180, 210, 240, 270, 300, 330, 360 and 420 days were used for observation of the length of the estrous cycle, and the numbers of ovulated and fertilized ova. The estrous cycle between the ages of 90 and 330 days presented a regular 4-day pattern. Thereafter, regularity of the cycle declined steadily between the ages of 360 and 420 days. All mice over 420 days old exhibited cessation of cyclicity and ultimately persistent diestrus. The average number of ova ovulated in mice aged between 90 and 240 days was consistent (11.8 to 11.4 ova), whereas a steady decline was observed for mice between 270 days old (10.5 ova) and 360 days old (4.8 ova). Ova were not recovered from oviducts of mice aged about 420 days. The average number of fertilized ova (2-cell stage) in mice between 90 and 210 days old showed no significant change (11.5 to 10.3), whereas the number began to decrease in mice aged between 240 days (8.7 fertilized ova) and 330 days (2.5 fertilized ova). No fertilized ova were recovered from the oviducts of mice around 360 days old. These findings demonstrate that the decline of reproductive activity is initially observed in the number of fertilized ova, followed by a decline in the number of ovulations and finally by loss of the estrous cycle.     

Dynamic Reduction of Plasma Decorin Following Ischemic Stroke: A Pilot Study

The aim of this study was to investigate the dynamic changes in plasma decorin concentration after acute ischemic stroke and to study its relationship with clinical stroke subtypes. We collected three plasma samples from patients with acute ischemic stroke (n?=?35) and controls (n?=?30): upon admission (1-3?days) between 3?days and 1?week (3-7?days), and between 7?days and 2?weeks (7-14?days). The relationship between Decorin concentration and Trial of ORG10172 in Acute Stroke Treatment (TOAST) subtypes and outcomes were evaluated. The concentration of decorin gradually decreased following the onset of stroke at all different time-points (<3?days, p?相似文献   

Role of endogenous nitric oxide (NO) and NO synthases in healing of indomethacin-induced intestinal ulcers in rats

We examined the roles of nitric oxide (NO) and NO synthase (NOS) isozymes in the healing of indomethacin-induced small intestinal ulcers in rats. Animals were given indomethacin (10 mg/kg, s.c.) and killed 1, 4 and 7 days after the administration. Indomethacin (2 mg/kg), N(G)-nitro-L-arginine methyl ester (L-NAME: a nonselective NOS inhibitor: 10 mg/kg) and aminoguanine (a relatively selective iNOS inhibitor: 20 mg/kg) were given s.c. once daily for 6 days, the first 3 days or the last 3 days during a 7-day experimental period. Both indomethacin and L-NAME significantly impaired healing of these lesions, irrespective of whether they were given for 6 days, first 3 days or last 3 days. The healing was also impaired by aminoguanine given for the first 3 days but not for the last 3 days. Expression of iNOS mRNA in the intestine was up-regulated after ulceration, persisting for 2 days thereafter, and the Ca(2+)-independent iNOS activity also markedly increased with a peak response during 1-2 days after ulceration. Vascular content in the ulcerated mucosa as measured by carmine incorporation was decreased when the healing was impaired by indomethacin and L-NAME given for either the first or last 3 days as well as aminoguanidine given for the first 3 days. These results suggest that endogenous NO plays a role in healing of intestinal lesions, in addition to prostaglandins, yet the NOS isozyme mainly responsible for NO production differs depending on the stage of healing: iNOS in the early stage and cNOS in the late stage.     

Biochemical changes in progressive muscular dystrophy. XII. Cyclic nucleotides in lymphoid and nonlymphoid organs of dystrophic mice

Concentrations of cAMP and cGMP were measured (per milligram DNA) in the lymphoid (thymus, spleen) and nonlymphoid organs (liver, brain, kidney, lungs, heart, pancreas, skeletal muscle, lens) of normal (+/+) and dystrophic (dy/dy) 129 ReJ mice aged 30, 60, and 90 days. The cAMP concentrations in the thymus did not reveal any significant differences at 30 and 60 days of dystrophy, but were considerably higher (2-fold) at 90 days. cGMP concentrations were decreased in the thymus at 30 days (0.20-fold) and markedly elevated at 60 (2-fold) and 90 days (3-fold) of the disease. The [cAMP]/[cGMP] ratio was increased (1.30-fold) at 30 days of dystrophy, and this was followed by a sharp decline at 60 days (2-fold), with a lesser decrease at 90 days (0.34-fold). In the spleen, the cAMP concentrations were augmented significantly in all stages of dystrophy (1.5- to 2.6-fold). cGMP (per milligram DNA) did not show any significant variation at 30 and 60 days of the disease but was increased (3-fold) at 90 days. The [cAMP]/[cGMP] ratio, which was enhanced in the spleen at 30 (2-fold) and 60 days (1.5-fold), demonstrated no change at 90 days of dystrophy. These results indicated significant differences in the concentration of cyclic nucleotides and their ratios in the thymus and spleen of 129 ReJ dy/dy mice. The modifications were not limited to lymphoid organs alone, having been noted in the nonlymphoid organs as well. These changes could, in turn, influence immune responsiveness and could cause immunodepression in dystrophic mice.     

Body condition during pregnancy and lactation and reproductive efficiency of mares

In Experiment I, 32 mares were equally allotted to the following treatments: mares fed to A) high body condition from 90 days prepartum to foaling and maintained in high body condition to 90 days postpartum, B) high body condition from 90 days prepartum to foaling and allowed to lose body condition to 90 days postpartum, C) lose body condition from 90 days prepartum to foaling and maintained in low body condition to 90 days postpartum, and D) lose body condition from 90 days prepartum to foaling and allowed to gain weight after foaling to attain a high level of body condition by 90 days postpartum. After three cycles, pregnancy rate at 30 days postovulation was lower (P<0.05) in C mares (50%) than in those in the other three groups (100%). Maintenance of pregnancy to 90 days was also reduced (P<0.05) in C mares (25%) when compared with A, D (both 100%) and B mares (88%). Foal growth to 90 days of age was similar in all treatments. In Experiment II, 927 mares were evaluated for body condition and monitored for reproductive performance. Pregnancy rate was lower (P<0.05) and number of cycles/conception was higher (P<0.05) for barren and maiden mares entering the breeding season in thin condition and for pregnant mares foaling in thin condition (condition score less than 5.0) when compared with mares with a higher level of condition. Also, onset of estrus and ovulation appeared to be delayed in barren and maiden mares entering the breeding season in thin condition. Breeding efficiency was enhanced in mares entering the breeding season or foaling at a condition of 5.0 or above. Initial excess stores of body fat enhanced fertility. There were no detrimental effects of excess body fat stored in late gestation.     

阴天和晴天对黄河三角洲芦苇湿地净生态系统CO2交换的影响

云量以及大气气溶胶含量变化引起的阴天和晴天会对局地的微气候环境产生综合效应, 影响地面接收的太阳辐射强度, 同时引起环境因子的变化, 最终对净生态系统CO₂交换(NEE)产生影响。该文通过涡度相关系统以及微气象梯度观测系统, 对黄河三角洲芦苇(Phragmites australis)湿地NEE以及环境要素进行了观测。在自然条件下选择12对相邻阴天和晴天数据, 在生物要素(生物量、叶面积指数)、土壤水分以及养分特征保持不变的前提下, 揭示了阴天和晴天变化对湿地生态系统NEE的光响应和温度响应的影响。结果表明: 12对阴天和晴天生态系统NEE的日平均动态均呈“U”型曲线, 但阴天NEE的变幅较小。晴天条件下湿地生态系统NEE的日均值显著高于阴天(p < 0.01)。阴天和晴天湿地生态系统NEE与光合有效辐射(PAR)之间均呈直角双曲线关系, 但晴天条件下, 最大光合速率(A_max)显著大于阴天(p < 0.01), 同时白天生态系统呼吸(R_eco,daytime)也显著大于阴天(p < 0.01)。不论阴天还是晴天, R_eco,daytime与气温均呈显著的指数关系。晴天湿地生态系统呼吸的温度敏感系数Q₁₀ (5.5)远大于阴天(1.9)。阴天和晴天昼间PAR差值以及气温差值对NEE差值的协同影响达到63%。     

Use of dibunol in pharmacological correction of post-vagotomy hypoxia of digestive organs in rats

1, 7, 14, 30 and 60 days after bilateral sub-diaphragmatic truncal vagotomy tension of oxygen (pO2) in liver, stomach and small intestine (jejunum) was determined. It was demonstrated that vagotomy leads to a decrease of pO2 in all investigated organs 1 day after the operation (such changes were observed in sham-operated rats) and 30 days, in jejunum--after 7 days, in liver--after 14 days, in stomach--after 60 days. Dibunol introduction in vagotomized rats during 29 days (starting from the second day after operation) results in pO2 normalization in all investigated organs.     

Development of isoproterenol-induced cardiac hypertrophy

The development of cardiac hypertrophy was studied in adult female Wistar rats following daily subcutaneous injections of isoproterenol (ISO) (0.3 mg/kg body weight). A time course was established for the change in tissue mass, RNA and DNA content, as well as hydroxyproline content. Heart weight increased 44% after 8 days of treatment with a half time of 3.4 days. Ventricular RNA content was elevated 26% after 24 h of a single injection and reached a maximal level following 8 days of therapy. The half time for RNA accumulation was 2.0 days. The total content of hydroxyproline remained stable during the first 2 days of treatment but increased 46% after 4 days of therapy. Ventricular DNA content was unchanged during the early stage (1-4 days) of hypertrophic growth but increased to a new steady-state level 19% above the controls after 8 days of treatment. Intraventricular pressures and coronary flow measures were similar for control and experimental animals following 4 days of developed hypertrophy. However, dP/dt in the ISO-treated hearts was slightly but significantly (P less than 0.05) elevated. These data indicate that the adaptive response to ISO shows an early hypertrophic phase (1-4 days) characterized by a substantial increase in RNA content and cardiac mass in the absence of changes in DNA. However, prolonged stimulation (8-12 days) appears to represent a complex integration of both cellular hypertrophy and hyperplasia within the heart.     

Effect of dietary oils enriched with n-3 fatty acids on survival of mice

Female mice were fed a conventional diet, shifted at 119 days of age to a diet supplemented with 10 wt % lard (Lar), high-linoleic (n-6) safflower oil (Saf), rapeseed oil (low-erucic, Rap), high-alpha-linolenic (n-3) perilla oil (Per) or a mixture (1:9) of ethyl docosahexaenoate (n-3) and soybean oil (DHA/Soy). Weight gain was less in the Per group than in the other groups at 497 days of age. In the Rap group, proteinuria was more severe than in the Saf, Per and DHA/Soy group, and hepatic triacylglycerol accumulation was greater than in the other groups. The mean survival time of the DHA/Soy group (753 days) was significantly longer than in the Lar group (672 days) and Saf group (689 days); the differences among other groups (e.g., 701 days in the Per group and 712 days in the Rap group) were not statistically significant. Although DHA is more susceptible to auto-oxidation than other major fatty acids in the air, an oil containing DHA was found to increase the survival of mice. Rapeseed oil that decreases the survival time of SHRSP rats was found to be safe in the mouse strain used in this study when survival was an end point.     

Effect of thirty days of creatine supplementation with phosphate salts on anaerobic working capacity and body weight in men

The purpose of this study was to determine the effect of 30 days of single-dose creatine supplementation with phosphate salts (CPS) on body weight (BW) and anaerobic working capacity (AWC) in men. Using a double-blind design, 32 men randomly received 1 serving of either CPS (5 g Cr + 4 g phosphate) (n = 17) or 20 g of dextrose as placebo (PL) (n = 15) for 30 days. AWC determined from the Critical Power Test and BW were measured at baseline, 10 days, 20 days, 30 days, and 10 days post-supplementation. Results (2 x 5 ANOVA) showed no significant differences between groups for AWC at any time point; however, BW was significantly increased at 10 days in the CPS group (1.0 kg) vs. PL (0.0 kg), and remained elevated for the duration of the study. These findings suggest that a single 5 g x d(-1) dose of CPS for 30 days increases BW but is not effective for increasing AWC in men.