Transfer of cultured bovine embryos

A total of 126 bovine embryos were surgically collected from 16 superovulated donor heifers 5 days after estrus and randomly selected for either immediate transfer to synchronized recipients or $\text{in}$$\text{vitro}$ culture at 37°C for 24 hours and subsequent transfer. Twenty-four of 56 (42.8%) embryos maintained for 24 hours in Ham's F10 medium supplemented with 10% heat treated fetal calf serum (HTFCS) and transferred to 32 recipients produced live calves. Survival of 70 noncultured embryos transferred to 35 recipients was 55.7% (39 calves). The percentages of recipients that were diagnosed pregnant at 42 days with cultured and control embryos were 59.4% ($\text{19}\text{32}$) and 74.3% ($\text{26}\text{35}$), respectively. No statistical difference was observed between the $\text{in}$$\text{vitro}$ cultured and control embryos for viability following transfer to recipient females.In a second study, Day 7 embryos maintained in Ham's F10 medium supplemented with 10% HTFC serum for various culture periods were tested for viability following nonsurgical transfer to recipient females. A total of $\text{1}\text{5}$, $\text{1}\text{3}$ and $\text{0}\text{4}$ embryos cultured for 24, 48 and 72 hours, respectively, resulted in pregnant recipients following transfer.     

Laparoscopic embryo transfer in domestic sheep: A preliminary study

An effective, minor-invasive technique for embryo transfer in sheep was developed using a laparoscopic transabdominal approach. Twelve recipient ewes received embryos either by conventional laparotomy or by laparoscopy. The estrous cycle of recipient ewes was synchronized using a progestagen-impregnated vaginal pessary/pregnant mares' serum gonadotropin treatment regimen. Donor ewes were superovulated with follicle stimulating hormone or human menopausal gonadotropin, bred with a ram of one breed and laparoscopically inseminated $\text{in}$$\text{utero}$ with semen from a different sheep breed. Five to six days after estrus, embryos were transferred laparoscopically into the terminal one-half of the recipient's uterine horn ipsilateral to the ovary with prominent corpus luteum development. Pregnancy was diagnosed by transrectal ultrasonic procedures, and by direct laparoscopic examination of the uterus. Of six laparoscopic transfers, three resulted in single births; one of six laparotomy transfers resulted in a live birth. Breed appearances of the four lambs born indicated that two of the offspring resulted from laparoscopic artificial insemination of the donor ewe. The results demonstrated that laparoscopic transfer of embryos was a rapid and safe procedure, easily applied to an ovine embryo transfer program and with potential for similiar studies in other species.     

Occurrence of proteinase a isoinhibitors in wild type yeast strains and commercial baker's yeast

The occurrence of the proteinase A inhibitors 2 and 3 was investigated in wild type strains of $\text{Saccharomyces}\text{cerevisiae}$ and $\text{Saccharomyces}\text{carlsbergensis}$ as well as in several strains of commercial baker's yeast. Haploid and diploid strains of $\text{Saccharomyces}\text{cerevisiae}$ contain only proteinase A inhibitor 3 whereas in $\text{Saccharomyces}\text{carlsbergensis}$ only proteinase A inhibitor 2 is found. Strains of commercial baker's yeast contain either proteinase A inhibitor 3 or both inhibitors in a constant ratio of 1:3. Single cell cultures isolated from a strain of commercial baker's yeast also contain a mixture of the two inhibitors. Therefore, baker's yeast is not a mixture of two different cell types but the genome for both inhibitors is present in each single cell. In general, the results indicate that the occurrence of the two proteinase A inhibitors is determined genetically and, therefore, they may be called “isoinhibitors”.     

The development of lactate and malate dehydrogenases in the C57BL-6 mouse kidney

The development of lactate dehydrogenase (LDH; EC 1.1.1.27) and malate dehydrogenase (MDH; EC 1.1.1.37) was measured in the kidney of male and female $\text{C57BL}\text{6}$ mice from ages prenatal 16 days to 80 days. Maximum reactions rates of the enzymes were measured in vitro by following the reduction of the nicotinamide-adenine dinucleotide spectrophotometrically.Analysis of variance showed no significant sex difference for LDH and MDH. There was a significant sex difference for the ratio LDH:MDH and a significant age difference for LDH, MDH, and the ratio LDH:MDH. In the male and female, LDH activity increased from prenatal 16 days to 30 days. Malate dehydrogenase activity reached adult values at 22 days in the male and at 30 days in the female. The ratio LDH:MDH in the male decreased from prenatal 16 days to 3 days, after which the ratio continued to decline to 20 days at a less rapid rate. This general pattern was also found in the female followed by a further decline in the ratio at 50 days.The development of LDH and MDH in the $\text{C57BL}\text{6}$ mouse is tissue specific and probably parallels the development of the tissue's function. In the case of the kidney, LDH and MDH development may reflect maturation of mitochondrial function and the kidney's ability to concentrate urine.     

Effect of heat on frog sciatic nerve determined by X-ray diffraction

Low-angle X-ray diffraction patterns have been recorded from frog sciatic nerves in Ringer's solution after heat treatment from 20 to 80°C. The X-ray patterns were obtained from the heat treated specimens after cooling to room temperature. The normal X-ray pattern of frog sciatic nerve in Ringer's solution with $\text{d=171}\text{A}\text{?}$ was maintained from 20 to 58°C. Above 58°C, a new high temperature pattern based on a repeat period of $\text{d?435}\text{A}\text{?}$ was recorded from the nerve in Ringer's solution. The physical state of nerve myelin after heat teratment at a temperature ?58°C has been identified as the anomalous swollen state. Anomalous swelling takes place in units of four membranes.     

Tyrosine's pressor effect in hypotensive rats is not mediated by tyramine

Tyrosine, the amino acid precursor of catecholamines, increases blood pressure (BP) in hemorrhaged hypotensive rats. Since tyrosine may also be decarboxylated to form $\text{tyramine}$^∞, which releases norepinephrine from sympathetic terminals, we tested the hypothesis that $\text{tyramine}$ formation might mediate tyrosine's ability to increase BP. Three lines of evidence indicate that tyrosine does not act via this mechanism: pretreatment with reserpine blocked $\text{tyramine's}$ but not tyrosine's pressor activity; pretreatment with hexamethonium left $\text{tyramine's}$ effect intact but blocked the pressor response to tyrosine; and plasma $\text{tyramine}$ did not increase after an hemodynamically-active dose of tyrosine (100 mg/kg).     

The estrogenic activity of DDT: Invivo and invitro induction of a specific estrogen inducible uterine protein by o,p'-DDT

The pesticide o,p'-DDT stimulates the production of a specific uterine protein, the so-called induced protein or IP, normally associated with an estrogenic response of the uterus. $\text{In}$$\text{vivo}$ stimulation of IP production is observed 1 hour after the administration of 250 mg/kg of o,p'-DDT to immature rats. $\text{In}$$\text{vitro}$ stimulation of IP production is observed after a 1 hour incubation of uteri with 100 μM o,p'-DDT. This $\text{in}$$\text{vitro}$ response is blocked by Actinomycin D. In contrast to o,p'-DDT, which binds to the cytoplasmic estrogen receptor and stimulates IP production, p,p'-DDT which does not bind well to the estrogen receptor does not stimulate IP production $\text{in}$$\text{vitro}$. These findings represent the first report of an estrogenic effect of o,p'-DDT in a completely $\text{in}$$\text{vitro}$ system.     

Effects of morphine on one-trial appetitive learning

Rats given intraventricular injections of morphine before and after a single training trial on a water-finding task performed significantly better on a retention test 24 hours later than rats given Ringer's injections instead of morphine either before $\text{or}$ after the training trial, and significantly better than rats given Ringer's before and after the training. Tial. The effect of morphine was interpreted as a retroactive strengthening of associations that the rats had formed during the training trial. The phenomenon suggests a possible model for understanding certain positively reinforcing actions of morphine.     

Comparison of the in vivo clearance of des-AA and des-AABB rat fibrin monomers prepared by different methods

Solubilization of fibrin monomers (Fm's) is usually performed with dilute acetic acid, urea or sodium bromide. These solvents can affect the biological properties of Fm's. Therefore we describe a new method to keep Fm's in solution, under milder conditions i.e. by generating them in Dcate solutions and avoiding non-physiological conditions. The in vivo behaviour of iodinated rat Fm's injected in rats and prepared by this new method was compared with that of Fm's dissolved in acetic acid, urea or sodium bromide.Fm's prepared in Dcate solutions accumulate rapidly, within 10 minutes after injection, in all organs tested, predominantly in kidney, liver and lung, probably by interaction with endothelial cells. The blood radioactivity remains nearly constant during the first 90 minutes and decreases thereafter exponentially. Fm's dissolved in sodium bromide behave similarly. However, Fm's dissolved in acetic acid or urea behave differently and do not accumulate in organs. This suggests that Fm's loose their capability to accumulate in organs and probably to interact with endothelial cells when they have been dissolved in acetic acid or urea.The slow exponential clearance phase does not differ significantly between the various Fm's and their $\text{T}\text{1}\text{2'S}$ are estimated to lie between 5 and 7 hours.     

Synchronization of estrus in cyclic beef heifers with the prostaglandin analog alfaprostol

Seventy-eight Hereford-Angus crossbred heifers were injected intramuscularly twice with 6 mg of alfaprostol^b in 6 ml of propylene glycol. On each representative day of a 20-day estrous cycle (estrus = Day 0), either three or four heifers received their first injection. The second injection was given 12 days after the first, regardless of the response to the first injection. Thirty-nine heifers were not treated. The first alfaprostol injection reduced serum progesterone to less than 1 ng/ml in all heifers injected after Day 4. A total of 79.5% ($\text{62}\text{78}$) of the heifers exhibited estrus by five days after the first injection. Average interval from injection to estrus was 63 hours. The second injection occurred on Days 6 through 16 for all but one heifer, with 75.6% ($\text{59}\text{78}$) falling on Days 8 through 11 of the estrous cycle. Estrus was detected in 93.6% ($\text{73}\text{78}$) of the heifers within five days after the second injection, with an average interval to estrus of 66 hours.Day of cycle at second injection did not affect the interval to estrus. Conception occurred in 79.4% ($\text{58}\text{73}$) of the heifers inseminated in the five days after the second injection. Occurrence of estrus and conception was no different in treated heifers after five days of the insemination period than in nontreated heifers after 21 days of the insemination period, where 94.9% ($\text{37}\text{39}$) were observed in estrus and 83.8% ($\text{31}\text{37}$) conceived. Overall percent conception for a 55-day insemination period was 89.7 ($\text{70}\text{78}$) for treated and 87.2 ($\text{34}\text{39}$) for nontreated heifers. Day of cycle at first or second injection did not affect conception after the second injection. Some signs of estrus were observed in 11 of the 16 heifers injected before Day 5.A second trial to determine if alfaprostol induced luteolysis early in the cycle was conducted. Twenty purebred Angus, Hereford, or Simmental heifers received either one or two injections of alfaprostol on either Day 1, 2, 3, or 4. Only five heifers showed any signs of estrus, and the three that were inseminated did not conceive. Subsequent cycle length indicated that luteolysis occurred in only one heifer.Data suggest that alfaprostol is an effective luteolytic agent in cyclic beef heifers after Day 4 and that two injections 12 days apart will effectively synchronize estrus in heifers when distributed throughout the cycle at the first injection without affecting conception rate.     

Characterizations and constructions of reverberating networks

Consider the family $\text{G}$_n of all n neuron networks whose dynamical behaviors are described by Caianiello's neuronic equations, and also its subfamily $\text{R}$_n of all reverberating networks each of whose neuronic equations have only periodic solution (states), i.e., without having any transient states. This paper is specifically concerned with characterizations of the subfamily $\text{R}$_n. First, we show that $\text{R}$_n is contained in a subfamily $\text{S}$_n of $\text{G}$_n consisting of all self-dual networks. We introduce Chow's matrix corresponding to each network of $\text{S}$_n, using Chow parameters and some algebraic operations {$\text{2}$_α} applied to the coefficient matrix of the network in $\text{S}$_n, such as interchanges of coefficients between two neurons or changes of their signs. Then we give some necessary conditions on Chow's matrix under which any network in $\text{S}$_n belong to $\text{R}$_n, and a necessary and sufficient condition on the coefficient matrix. We also discuss relations between Chow's matrix and the maximum period of reverberations. In particular, it is shown that Chow's matrix of a network in $\text{R}$_n is symmetric if and only if the maximum period of reverberations is less than three. By virtue of these results, we propose two methods of construction of networks in $\text{R}$_n. The first method is an inductive construction. The second is based on the algebraic operations.     

Interactions of chlorinated hydrocarbon pesticides with the 8S estrogen-binding protein in rat testes

The effect of certain DDT analogs on the binding of ³H-estradiol to the 8–9S estrogen binding protein of rat testicular cytosol was studied by sucrose sedimentation analysis. The binding of ³H-estradiol to testicular cytosol was inhibited by o,p'DDT, a DDT analog which is estrogenic in the intact female, but not by p,p'DDE which is a nonestrogen in the female. The pesticide methoxychlor, which is estrogenic $\text{in vivo}$ in the female, failed to inhibit ³H-estradiol binding, presumably requiring metabolic activation for binding to the testicular cytosol. In fact, its di-demethylated metabolite 2,2-bis(p-hydroxyphenyl)-1, 1,1-trichloroethane (HPTE), also estrogenic $\text{in vivo}$, caused $\text{marked}$ suppression of ³H-estradiol binding.     

Early identification of non-pregnant and pregnant ewes in the field using circulating progesterone concentration

A method for early indentification of non-pregnant and pregnant ewes is described. It is applicable to field research situations where mating data for individual ewes cannot be collected and requires three plasma progesterone measurements from each ewe over a 12-days period.Ewes were diagnosed non-pregnant according to whether their lowest progesterone concentration (p) was below or above a “discriminatory value”. This value was chosen after examining the overall frequency distribution of values of log₁₀p.In experiment 1, $\text{25}\text{27}$ non-pregnant ewes and $\text{64}\text{65}$ pregnant ewes (20 to 31 days post-mating) were diagnosed correctly (96.7% accuracy). In experiment 2, $\text{40}\text{41}$ non-pregnant ews and $\text{45}\text{48}$ pregnant ewes (21 to 34 days post-mating) were diagnosed correctly (95.5% accuracy).     

Inhibition of bovine adrenocortical cytochrome P-450scc by 3,3'-dimethoxybenzidine

The effect of 3,3'-dimethoxybenzidine ($\text{o}$-dianisidine) on the conversion of cholesterol to pregnenolone was investigated in a reconstituted side chain cleavage system using enzymes purified from bovine adrenal cortex; d-$\text{p}$-aminoglutethimide was also assayed under similar conditions for comparison. 3,3'-Dimethoxybenzidine was found to be a potent inhibitor of pregnenolone formation, causing 50% inhibition at a concentration of 1.5 μM when using 70 μM cholesterol — this dose is approximately one fourth that required of 3-methoxybenzidine and one twentieth that required of benzidine for equal inhibition. In the same system, d-$\text{p}$-aminoglutethimide exhibited an I₅₀ value of about 55 μM. No effects of 3,3'-dimetoxybenzidine on adrenodoxin reductase or adrenodoxin activities could be detected, and inhibition of side chain cleavage could be relieved by dilution suggesting that the inhibitor acts by reversibly binding to cytochrome P-450scc.     

Stereochemistry of dihydrofolate reductase inhibitor antitumor acents: Molecular structure of “Baker's antifol” (NSC 139105, triazinate) and “insoluble Baker's antifol” (NSC 113423)

The crystal and molecular structures of 1-[3-chloro-4-($\text{m}$-dimethylcarbamoylbenzyloxy)] phenyl-4,6-diamino-1,2-dihydro-2,2-dimethyl-$\text{s}$-triazine ethanesulfonate, (Baker's antifol), and 1-[4-(N-[3′-methyl-4′-fluorosulfonyl] phenyl) propanamide] phenyl-4,6-diamino-1,2-dihydro-2,2-dimethyl-$\text{s}$-triazine ethanesulfonate dihydrate (insoluble Baker's antifol) have been determined by X-ray crystallography. These compounds are, respectively, reversible and irreversible inhibitors of dihydrofolate reductase and show clinical promise for use in cancer chemotherapy. Both molecules adopt an extended conformation and are protonated at one of the triazine ring nitrogens.     

Onset of the receptive and proceptive components of feminine sexual behavior in rats following the intravenous administration of progesterone

The present study was carried out in order to assess the time course of action of progesterone (P) in the facilitation of complete feminine sexual behavior. Female rats (estrogen primed via 5% E₂ Silastic capsules) were given 200 μg of P either intravenously (iv) or subcutaneously (sc), and tested for estrous behavior at $\text{1}\text{4}$, $\text{1}\text{2}$, 1, 2, and 4 hr after treatment. Among iv-treated animals, significant amounts of lordosis behavior were seen as early as $\text{1}\text{2}$ hr, and a dramatic rise in solicitation behavior was observed at 2 hr. Although sc-treated animals displayed significant amounts of lordosis and solicitation behavior at 2 hr, the behavior was not maximal until 4 hr. Intravenous administration of 400 μg P was equipotent to 200 μg P, whereas 50 μg of iv P was relatively ineffective. A dual mechanism hypothesis pertaining to progesterone's actions in the facilitation of both the receptive and preceptive components of feminine sexual behavior in rats is discussed.     

Social play behaviours and insect predation in northern grasshopper mice (Onychomys leucogaster)

Play behaviours of northern grasshopper mice, $\text{Onychomys leucogaster}$, were observed from 27 to 61 days of age and after a brief period of social isolation. The mice were also observed during a simple test of cricket predation. With the exception of an active play-soliciting response, the play behaviours were quite similar to those described for other rodents. Play declined with increasing age and was strongly potentiated by social isolation. There was no discernable relationship between any of the play measures and efficiency of cricket predation. There were no detectable sex differences in either play or predation.     

Two tissue culture media for production of lepidopteran cells and nuclear polyhedrosis viruses

Two media supporting the growth of several established lepidopteran cell lines in monolayer and suspension culture are described. The medium designated $\text{BML-TC}\text{10}$ was developed specifically as an inexpensive medium for production of cells of Spodoptera frugiperda and the homologous nuclear polyhedrosis virus (NPV) of this species. Simultaneously, a second medium was formulated in which the amino acid requirements were provided by enzymatic protein hydrolysates, one of which was termed $\text{BML-TC}\text{7A}$. Several cell lines could be adapted easily to this medium. $\text{BML-TC}\text{10}$ supported growth of S. frugiperda cells and production of the NPV's of S. frugiperda and Autographa californica. $\text{BML-TC}\text{7A}$ supported the growth of cells of S. frugiperda. Carpocapsa pomonella, Heliothis zea, and Trichoplusia ni. Cells of the latter produced the polyhedra of T. ni and A. californica NPV's in this medium.     

Prostaglandin and the osmoregulatory role of prolactin in a teleost

Prolactin stimulates elevation of plasma chloride concentrations in $\text{Fundulus grandis}$. Treatment of fish with inhibitors of prostaglandin synthesis (indomethacin or aspirin) prevents elevation of plasma chloride following prolactin injection. Prostaglandin E₁ stimulates increased plasma chloride concentrations in either indomethacin- or aspirin-treated fish. We theorize from these results that at least some of prolactin's actions with regard to teleostean osmoregulation are mediated by stimulation of prostaglandin synthesis.