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121.
Severe freezing injury was produced in the hind foot of 26 mongrel dogs. All dogs were given daily whirlpool treatment and protective bandaging for 14 days following injury. In addition, certain dogs received a vasodilator, fasciotomy, or both vasodilator and fasciotomy following injury. Deep foot temperatures, foot volumes, tissue pressures, and 14 day tissue loss-salvage scores were compared. Significant differences between fasciotomy and nonfasciotomy dogs were seen in foot temperature, volume, and tissue pressure immediately following fasciotomy. Though there was no significant difference in 14 day tissue loss, there was clinically apparent prolongation of integrity of the local vascular system for 2 to 5 days following fasciotomy, and total foot salvage in several dogs receiving fasciotomy.  相似文献   
122.
Four biochemical mechanisms have been shown to operate in the oocytes of amphibians and teleosts: (1) amplification of the 28 S and 18 S genes, (2) noncoordinate accumulation of 5 S RNA and 28 S + 18 S RNA, (3) storage of 5 S and transfer RNA made in excess by small oocytes within nucleoprotein particles, (4) expression of different 5 S genes in oocytes and somatic cells. We have tried to extend these observations to another group of vertebrates, i.e., selacians (Chondrichthya). Our data suggest that ribosomal gene amplification is low or absent in the oocytes of the dogfish Scyliorhinus caniculus. However, previtellogenic oocytes of this species accumulate more 5 S RNA than needed for ribosome assembly. Transfer and 5 S RNA present in small oocytes are probably not free in the cell sap. A substantial fraction of these RNAs sediments at 10 S when homogenates of immature ovaries are centrifuged in sucrose density gradients. In contrast to what we observed in amphibians and teleosts, 5 S RNA from ovaries of S. caniculus is identical in sequence to 5 S RNA from liver. Among the four mechanisms mentioned above, the second and probably the third one are used by the oocytes of S. caniculus. Mechanism (4) is absent in this species. No definitive conclusion can be drawn concerning mechanism (1), i.e., ribosomal gene amplification.  相似文献   
123.
Heterosexual interactions of pairs of stumptail macaques (Macaca arctoides) were studied in relation to the female menstrual cycle and after ovariectomy. Five intact male and 10 tubal-ligated female macaques were observed in laboratory pair tests of 20-mins duration, and data were obtained on various male and female behaviors. Each male was tested with the same two females during four 40-day observation periods. Males were tested daily and females were tested every other day. After two 40-day testing periods, one female partner of each male was ovariectomized and the other was sham-operated. Blood was collected regularly from the females during the course of observation and serum levels of estradiol and progesterone were determined by radioimmunoassay. The midcycle peak of estradiol was observed to occur approximately 18 days prior to menses. A distinct secondary peak in estradiol was observed to occur during the luteal phase of all cycles examined. Of 28 different male and female behaviors studied only female presentation to male sexual contact showed a significant midcycle peak related to the endogenous estradiol surge. After ovariectomy a significant decrease in the frequency of several male copulatory behaviors was observed, but most males continued to copulate regularly with their spayed partners throughout the period of this study. Thus, the pattern of copulatory behavior observed in stumptail macaques over the cycle of the female partner and subsequent to ovariectomy differs from that observed in other macaque species studied in the laboratory. It is concluded that cyclical fluctuations in the level of ovarian hormones are not significantly related to measures of sexual interactions in laboratory tests of this species, although the maintenance of copulation and associated behaviors at high levels depends to some degree upon the ovary.  相似文献   
124.
We have previously reported that lymphocytes from W/Fu rats immunized with syngeneic (C58NT)D tumor cells were cytotoxic against these cells in a 4-hr 51Cr release assay. We have investigated the feasibility of cryopreserving lymphocytes and target cells and have selected freezing conditions which provide good yields of viable cells and functional activity. Lymphocytes from different animals had a recovery of 60–80% viability which resulted in a corresponding 55–75% recovery of cytotoxic activity. Repeated testing of lymphocyte cytotoxicity from a pool of frozen spleen cells against either fresh or frozen (C58NT)D cells gave reproducible cytotoxicity. In addition, recovery of high levels of lymphocyte function was also demonstrated when cryopreserved cells were employed in long-term cytotoxic assays, i.e., 3H-proline and 125IUdR release assays, in the lymphoproliferative response to mitogens (PHA and Con A)3 or tumor cells (MLTI) as measured by 3H-thymidine incorporation, and in the in vitro generation of secondary cytotoxicity.By employing these cryoprotective techniques it is possible to have: 1) a population of lymphoid cells with known functional activity and 2) a pool of target cells with known susceptibility to lysis and antigenic content. Furthermore, the use of frozen cells as internal standards in each test also permits the analysis of assay variation as well as the study of variation in various cell types.  相似文献   
125.
The influence of suckling stimulation upon postpartum aggression was studied by removing the nipples (thelectomy) of female mice at various times during pregnancy and lactation. Prepartum thelectomy, regardless of whether it was performed prior to mating or shortly before parturition, in combination with the fostering of young, prevented the exhibition of aggression. The aggressive behavior of females thelectomized following either 2 or 5 days of suckling experience was similar to that of normal lactating females. However, only 25% of animals thelectomized following 24 hr of suckling experience exhibited aggressive behavior. The results demonstrate that suckling stimulation is important for the initiation of postpartum aggression but is not essential in animals that have had at least 48 hr of suckling experience.  相似文献   
126.
Two enantiomeric cuparene-type sesquiterpenoids, (R)-(−)-cuparene (1) and (R)-(−)-δ-cuparenol (2), have been isolated from the liverwort, Bazzania pompeana. The structures and absolute configurations of the two compounds have been determined.  相似文献   
127.
A radioimmunoassay for plasma estradiol-17β was developed using polyethylene glycol to separate free from antibody-bound hormone. Specificity for estradiol-17β was achieved by a modified celite microcolunm procedure in which estradiol was.separated from interfering estrogens, including estrone. Using trace 3H-estradiol to monitor procedural losses, the method was shown to be sensitive and accurate. Intra- and inter-assay coefficient of variation of the method was 8.7 and 10.6%, respectively. Polyethylene glycol used for antibody precipitation appears to be a generally applicable method for steroid hormone radioimmunoassays. The simplicity, precision and rapid analysis, coupled with its lack of time dependence and ease in automation, makes this a convenient and practical method.  相似文献   
128.
129.
The removal of cobalt from cobalt(II) bovine carbonic anhydrase by pyridine-2-carboxylate, pyridine-2,6-dicarboxylate and 5-methyl-1,10-phenanthroline occurs via formation of an intermediate. This is presumed to be a ternary adduct of cobalt(II) enzyme with the ligand. In this, metal-protein bonds are loosened, probably via distortion of the normal geometry, resulting in accelerated breakdown of the adduct to apoprotein, compared with the behavior of the cobalt(II) enzyme alone. With 2-carboxy-1,10-phenanthroline, removal of metal is very rapid but no adduct is observed. Values of stability constants of the adducts and rate constants for their decomposition to apoprotein and their formation from apoprotein and cobalt(II) complex were measured at pH 5.5 and 25°C. Formation and dissociation rate constants for the adduct of cobalt carbonic anhydrase with pyridine-2,6-dicarboxylate could be measured from pH 5 to 7 and 10° to 25°C by stopped flow. Values of thermodynamic parameters for the various reactions agreed well with those estimated from the kinetic data.  相似文献   
130.
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