Regulation of oviduct function in pigs by local transfer of ovarian steroids and prostaglandins: a mechanism to influence sperm transport

Blood was collected from a prominent ear vein and from the arterioles supplying the caudal portion of each oviduct in 5 estrous animals. Sampling was arranged at 4 preovulatory intervals, and just after ovulation in the fifth animal. Steroid hormones and prostaglandins were determined by radioimmunoassay of plasma. Whereas the concentration of cortisol did not differ between peripheral and oviduct blood samples, the overall values for progesterone, androstenedione and estradiol were significantly higher in oviduct samples (P less than 0.001) - frequently by 5- to 10-fold or more. The concentration of these three hormones in oviduct blood corresponded, in most instances, with the number of preovulatory follicles or recent ovulations in the adjacent ovary but suitable statistical correlations could not be performed. Prostaglandin F2 alpha was also present in higher concentrations in oviduct compared with peripheral plasma (P less than 0.005), although pulmonary clearance of prostaglandins would have influenced the peripheral values. Differences in the concentration of prostaglandin E2 were not significant. A local transfer of follicular hormones from the ovarian vein to the ovarian and utero-tubal arteries is proposed as a means of regulating oviduct function. Elevated concentrations of steroids and prostaglandins transferred in this way would permit incisive changes in the patency and contractile activity of the isthmus, thereby facilitating the periovulatory phase of sperm transport from the caudal portion of the oviduct to the site of fertilization.

Use of serum theophylline determinations during acute asthma therapy in children

Analyses of 90 admissions to the Cincinnati Children's Hospital Center, Cincinnati, Ohio, were used to assess the effects of the routine availability of serum theophylline determinations (STD) in treating acute in-hospital asthma over three one-year review periods coinciding with the relative availability of STD. Significant differences were found between the first and third periods for the mean outpatient theophylline dose used on admission, the mean initial in-hospital intravenous dose, the mean initial oral dose during admission and the mean oral discharge dose. No statistical differences were noted in the length of hospital stay, duration of intravenous therapy or report of theophylline toxicity (despite the use of larger theophylline doses). Utilization of STD must be guided by cost-effective pharmacokinetic principles.

Uterine secretion of prostaglandin F2 alpha in anaesthetized pigs during the oestrous cycle and early pregnancy

Uterine blood was sampled by venepuncture or an indwelling catheter in a total of 33 cyclic gilts and 26 mated animals subsequently confirmed to contain embryos; jugular blood was obtained simultaneously from catheterised animals. Prostaglandin F2 alpha and progesterone were determined by radioimmunoassay of the plasma. The concentration of PGF2 alpha in uterine venous blood of cyclic animals remained below 1.0 ng/ml until the corpora lutea were 12 days old. Highest PGF2 alpha values were associated with 15-17 day corpora lutea, with a mean of 5.9 ng/ml for six samples on Day 17. Likewise, the PGF2 alpha concentration in the uterine blood of mated animals did not exceed 1.0 ng/ml until the corpora lutea were older than 12 days, and a mean value of 6.0 ng/ml was found by acute sampling with 15-day corpora lutea. The highest mean concentrations of PGF2 alpha in uterine blood from a series of 14 catheterised pregnant animals were 2.8 and 2.3 ng/ml, respectively, with 15- and 16-day corpora lutea. Values for PGF2 alpha on the 17th, 18th and 19th days of pregnancy showed a downward trend. There was considerable day to day variation in the mean uterine and peripheral concentrations of progesterone in mated animals, but there was no sustained depression in response to elevated PGF2 alpha concentrations. The results suggest that exocrine secretion of PGF2 alpha into the uterine lumen of pigs under the influence of trophoblastic oestrogens does not provide a sufficient explanation for the establishment of the corpora lutea of pregnancy. Further attention should be devoted to the luteotrophic--as distinct from anti-luteolytic--rôle of pig conceptuses at the time of maternal recognition of pregnancy. Circumstantial evidence for luteal sensitivity to chorionic gonadotrophins is included.

Morphology, histology and steroid hormones of the gonads in intersex pigs

Studies of 3 genetically female, intersex pigs revealed that only one showed oestrous cycles and lordosis, the other 2 exhibited various components of male sexual behaviour. Each uterus was a patent bicornuate structure, but 5 of the oviducts were incompletely formed. Two of the animals had bilateral ovotestes, whilst the third had a functional ovary on the right and an ovotestis on the left. The small ovarian portion of each ovotestis contained Graafian follicles which did not respond to a systemic injection of PMSG. The major portion of each ovotestis consisted of extensive interstitial tissue and seminiferous tubules devoid of germ cells. A structure closely resembling an epididymis adjoined the ovotestes. Concentrations of oestradiol and progesterone in plasma corresponded with those expected in the follicular phase of an oestrous cycle, but concentrations of testosterone represented approximately one-tenth of the values found in mature boars.

Sperm transport and reservoirs in the pig oviduct in relation to the time of ovulation

The rate of establishment of a population of viable spermatozoa in the oviducts was studied using a technique of post-coital transection in conjunction with subsequent examination of the proportion of eggs fertilized. Gilts were mated early in oestrus (before ovulation) or on the 2nd day of oestrus (after ovulation), and 30, 45 or 60 min later the reproductive tract was sectioned just above or below the utero-tubal junction in a total of 48 animals; these were slaughtered 1 or 2 days after the operation. Some fertilized eggs were recovered from 40 animals, and 72.3% of the 679 eggs examined were fertilized. Mean percentage fertilization increased overall (a) with the time elapsing from mating to transection, (b) with transection below the utero-tubal junction compared with in the caudal isthmus, and (c) with a post-ovulatory versus pre-ovulatory mating. In a further 6 gilts, the results of transection in the lower third of the oviduct 3 h after mating at the onset of oestrus indicated that spermatozoa were initially sequestered in the caudal portion of the isthmus. It is concluded that a population of spermatozoa sufficient to give maximum fertilization is established in the oviducts within 1--2 h of mating, thereby affording protection from the uterine invasion of polymorphonuclear leucocytes.

Distribution of spermatozoa in the utero-tubal junction and isthmus of pigs, and their relationship with the luminal epithelium after mating: a scanning electron microscope study

The epithelial cell morphology and distribution in the utero-tubal junction and isthmus of pigs was documented by scanning electron microscopy around ovulation. In animals mated at different times before slaughter, our observations confirmed that the utero-tubal junction and posterior part of the isthmus regulate the transport of spermatozoa. The utero-tubal junction appears clearly as a form of mechanical valve strongly limiting the number of sperm cells penetrating the oviduct. The isthmus, and especially its posterior part poor in ciliated cells, is a storage place for spermatozoa which appear as though trapped in the epithelial folds. It remains to be demonstrated if they stay in such reservoirs due to the constriction of the lumen by the thick muscular wall of the duct, or to some chemotactic attraction by tubal secretions, or simply due to adhesion on the epithelium. Our study supports the hypothesis that transport of spermatozoa in the isthmus towards the site of fertilization depends in part on ciliary motion. The instant direction of propagation appears random for spermatozoa escaping from the reservoirs. Other factors such as tubal contractions probably ensure that the resultant movement is a progressive ascent.

Transport of spermatozoa in the ewe: timing of the establishment of a functional population in the oviduct

The technique of post-coital transection of the oviducts from the uterus at various intervals after mating has been used to establish how soon a population of spermatozoa competent to fertilize the egg(s) first appears in the oviduct of the ewe. Fertilised eggs were not found as a sequel to transection at 4 or 6 hrs after mating, whereas the incidence of fertilization in a small series of ewes was 30 p. 100 following transection at 8 hrs and 100 p. 100 at 10 hrs. The mean number of spermatozoa associated with the zona pellucida at these later times increased from 2 to 13.4. The results are interpreted as indicating only a gradual progression of viable spermatozoa from the cervix to the oviduct, although the possible contribution of a rapid phase of sperm transport to the events of fertilisation is discussed. Finally, the isthmus rather than the cervix is reasoned to act as the functional sperm reservoir at the time of ovulation, with some form of peri-ovulatory programming of sperm release from this region of the tract.

Comparison of five information services as sources for bioavailability data

The usefulness of five drug information services in obtaining bioavailability data from journal literature is compared. The deHAEN Drugs in Use system, the Iowa Drug Information Service (IDIS), Index Medicus, MEDLINE and International Pharmaceutical Abstracts (IPA), each for a 10-year period, were searched for citations on bioavailability studies on the oral dosage forms of acetaminophen, lithium carbonate, phenytoin, nitrofurantoin and theophylline. Both quantity of references indexed and quality of data were considered. No significant difference was found in the mean value scores for the five services. Index Medicus provided 79 citations but required 7.7 hours of search time. MEDLINE yielded 62 citations but required only 1.1 hours to search. IPA, IDIS and deHaen had lower numbers of citations and intermediate search times. IPA, deHaen and Index Medicus all cited unique articles, with 11%, 7% and 3%, respectively. Index Medicus had the lowest percent of articles duplicated by two or more services (49%). The most comprehensive serch with the fewest duplicate citations would be obtained from searching deHaen's Drugs in Use, IPA and Index Medicus.

Effect of obtrusive measures on antibiotic compliance

The influence of compliance measurement activities on patient behavior was studied. The project measured the relationship among physical capsule counts, patient interviews, and the amounts of excreted ampicillin. The capsule counts and patient interviews were conducted in a manner that disguised their intent. Sixty college-age patients were assigned to one of three experimental groups: a telephone interview, a personal interview and capsule count, or a control group. Stimulation (interviews) occurred on the 2nd day of the prescribed regimen, and urine was collected on random days thereafter. Results indicated that both stimulation types were associated with more positive compliance rates. The influence diminished rapidly. The reactive influence of experimentor intervention associated with personal and phone communication was demonstrated.

The nature and occurrence of the acrosome reaction in spermatozoa of the domestic pig, Sus scrofa

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Steroid-binding proteins in follicular fluid and peripheral plasma from pigs, cows and sheep

No unusual steroid-binding proteins that might react with the oocyte or its investments could be detected in follicular fluid. Corticosteroid-binding globulin occurred in follicular fluid from pigs, sheep and cows, and sex hormone-binding globulin occurred in follicular fluid from sheep and cows. The bulk of the steroid in follicular fluid is bound to albumin with low affinity, indicating that steroid molecules can readily be released, and oestrogen can react with the oocyte and granulosa cells in a manner analogous to that demonstrated for target cells bathed with interstitial fluid. Pigs lack a sex-hormone binding globulin in blood plasma and, hence, in follicular fluid. Because no proteins exist in follicular fluid that would compete with antibodies to bind steroids, direct radioimmunoassay of follicular steroids appears to be a valid technique.

Sperm-egg interactions in the pig: monospermy, extensive polyspermy, and the formation of chromatin aggregates

The process of incorporation and metamorphosis of the sperm head within the vitellus has been examined by phase-contrast microscopy in a large series of pig eggs exhibiting either normal monospermic fertilization or extensive polyspermy. This latter condition was induced in vivo after increasing the numbers of capacitated spermatozoa in the Fallopian tubes by pre-ovulatory surgical insemination. Attention was drawn in monospermic eggs to the initial fusion between the spermatozoon and vitelline surface which produced a characteristic constriction in the equatorial region of the head. Immediately following cytoplasmic contact with the sperm nucleus, an increase in size was detectable in this structure, remnants of the inner acrosomal membrane having apparently been displaced during incorporation. In fixed preparations of activated eggs, there was some evidence that the morphologically transformed sperm nucleus underwent a brief period of shrinkage before commencing pronuclear formation. The most striking feature of the polyspermic condition was the number of spermatozoa that had entered the vitellus (2 to greater than 80), and the formation of aggregates of sperm head chromatin in eggs penetrated by more than 20-30 spermatozoa; the heads of at least 8 or 9 spermatozoa could participate in the formation of such an aggregate. Various unusual configurations were noted during breakdown of the midpiece in polyspermic eggs, and degeneration was also a general feature of the cytoplasm in situations of excessive polyspermy. Aspects of the block to polyspermy are discussed, and it is inferred that highly polyspermic pig eggs can still exhibit a zona reaction.

Post-partum oestrus in the sow in relation to the concentration of plasma oestrogens

Ten sows, three entire and seven which had been ovariectomized at different stages of late gestation, were observed for post-partum oestrus. Serial blood samples were collected from six sows during the pre-and post-partum periods, and plasma oestrogen concentrations determined by radioimmunoassay. Morphological aspects of ovarian activity in the entire sows were examined at laparotomy and at autopsy. Although peak values of oestrogen concentration in the plasma varied from 3-9 to 8-0 ng/ml between individuals, the pattern of oestrogen levels was similar for control and ovariectomized sows. Peak concentrations occurred just before parturition, and the timing of ovariectomy did not affect the incidence of the oestrogen peak. Oestrus was detected in one control and one ovariectomized sow at 46 and 40 hr post partum respectively, there being no evidence of ovarian activity in the entire sows. The occurrence of post-partum oestrus in a sow ovariectomized at Day 108 of gestation indicates that this phenomenon is not directly connected with ovarian secretion of oestrogens. The post-partum oestrus is apparently a result of the peak of feto-placental oestrogens that occurs at parturition.