Studies of pituitary function in lactating ewes.

The release of LH from the pituitary of lactating ewes was studied. In Exp. 1, ewes were injected with 50 microng oestradiol benzoate (OB), 2-0 mg testosterone propionate (TP) or oil only (control) on days 5, 10, or 20 after lambing. LH was measured in peripheral plasma samples obtained 20-38 h after treatment, and the ovulations were recorded. The number of ewes in which an LH release was detected, and the amount released, declined between Day 5 and 20 after OB treatment but increased after TP treatment. The releases of LH were not always accompanied by ovulation and the incidence of ovulation was higher in ewes treated with TP. In Exp. 2, lactating ewes were injected with 1 or 5 (at 2-h intervals) doses of 50 microng Gn-RH, on Days 12 or 25 after lambing. LH was measured in peripheral plasma samples collected every 2 h for 10 h and every 3 h for a further 70 h. Release of LH occurred in all ewes, the amount being greater in ewes receiving multiple injections and in ewes treated on Day 25. The incidence of ovulation was higher after treatment on Day 25. Multiple injections of Gn-RH appeared to reduce the incidence of abnormal corpora lutea.     

Changed control of cervical secretion from infertile ewes previously exposed to oestrogenic clover pasture

The amount of cervical mucus recovered from control ovariectomized ewes increased with increasing doses of oestradiol benzoate (OB), while the maximum Spinnbarkeit of mucus occurred at an intermediate dose of OB. Neither the amount nor the Spinnbarkeit of mucus varied with the dose of OB in ewes with permanent infertility caused by grazing oestrogenic pasture (clover-affected ewes). Furthermore, the increase in Spinnbarkeit of cervical mucus seen in normal ewes treated over a 3-day period with OB or with implants containing oestradiol did not occur in affected ewes. In control ewes treated repeatedly with OB, production of mucus declined within 5 days, but no change in secretion was detectable in clover-affected ewes. Therefore, neither the amount nor the duration of oestrogenic stimulation affected the cervical mucus in ewes with clover disease. Affected ewes produced more mucus than did controls in the absence of oestrogenic stimulation. It is concluded that the relatively normal volume of mucus in affected ewes treated with OB results largely from autonomous production. The Spinnbarkeit does not increase in these ewes because the ability of the cervix to respond to oestrogen is impaired.     

Receptivity in Mongolian gerbils: dose and temporal parameters of ovarian hormone administration

The dose and temporal effects of oestrogen and progesterone treatment on the induction of receptivity in female Mongolian gerbils were investigated. One group of animals was primed with 10 micrograms oestradiol benzoate (OB) 48 and 24 h prior to testing and received 500 micrograms progesterone (Pr) 0, 1, 2, 3, 6, 9, 12, 15, 18, 21 or 24 h prior to testing. These subjects were found to exhibit high levels of receptivity from hour 2 to hour 18. This is similar to the reported duration of heat during natural oestrus. A second group of animals were primed with 10 micrograms OB and were then given either 0, 10, 50, 100, 250 or 500 micrograms Pr 3 h prior to testing. Results indicated that the administration of 100 micrograms Pr could elicit high levels of receptivity. A final group of animals were given either 0.5, 1.0, 5.0 or 10.0 micrograms OB 48 and 24 h before testing and then 100 micrograms Pr 3 h prior to testing. It was found that only the 10 micrograms dose of OB elicited high levels of receptivity in these animals.     

Placental changes due to administration of diethylstilbestrol (DES)

Pregnant mice were injected with 12.5 micrograms DES/kg body weight or 25 micrograms DES/kg body weight daily from gestation day 9 through day 12 or 16 and sacrificed on day 13 or 17. Placentas of DES treated animals were smaller than controls, the effect being dose dependent. Histologic changes in 13 gestation day placentas regional thinning of the labyrinth associated with an apparent inhibition of trophoblast maturation and development of fetal blood vessels. Knots of mononuclear cells form in the labyrinthine region of 13 day placentas exposed to the higher dose of DES. By 17 days gestation, coagulative necrosis is common in the decidua basalis, being most severe in those animals receiving 25 micrograms DES/kg. In many placentas the labyrinthine region is absent. The only remaining elements are trophoblast cells, giant cells and glycogen-containing cells. Fetal deaths associated with the lower dose of DES increased with time whereas 100% fetal mortality was associated with the higher dose.     

Evaluation of the possible direct effects of gonadotrophin-releasing hormone analogues on the monkey (Macaca mulatta) testis

In Exp. 1, the effect of treatment with a GnRH agonist on basal concentrations of serum testosterone and peak values of serum testosterone after administration of hCG was determined. One group of adult male monkeys was treated with a low dose (5-10 micrograms/day) and a second group with a high dose (25 micrograms/day) of a GnRH agonist for 44 weeks. Basal and peak testosterone concentrations were both significantly reduced by GnRH agonist treatment in all groups compared to untreated control animals, but the % rise in serum testosterone above basal values in response to hCG administration was unchanged by agonist treatment. In Exp. 2, the GnRH agonist (100 or 400 ng) or a GnRH antagonist (4 micrograms) was infused into the testicular arteries of adult monkeys. The agonist did not alter testosterone concentrations in the testicular vein or testosterone and LH values in the femoral vein. In Exp. 3, testicular interstitial cells from monkeys were incubated with three concentrations (10(-9), 10(-7) and 10(-5)M) of the GnRH agonist or a GnRH antagonist with and without hCG. After 24 h, neither basal nor hCG-stimulated testosterone production was affected by the presence of the GnRH agonist or antagonist. The results from all 3 experiments clearly suggest that GnRH agonist treatment does not directly alter steroid production by the monkey testis.     

Induction of persistent diestrus followed by persistent estrus is indicative of delayed maturation of tonic gonadotropin-releasing systems in rats

The relationship between the amount and duration of administration of estradiol benzoate (EB) to newborn female rats and the induction of sterility was examined in 407 animals. Vaginal smear patterns were classified into 3 types according to the incidence of vaginal proestrus and estrus over a 10-day period: persistent estrous (PE), persistent diestrus (PD), and intermediate (INT), so that the changes in vaginal smear patterns could be analyzed quantitatively. Incidence of the PE pattern was most frequent in the rats that received a single injection of 10 micrograms EB on the day of birth (Day 1). Almost all of the animals receiving 10 daily injections of 10 micrograms EB from Day 1 showed persistent diestrus until at least 100 days of age. In the rats that were given 5 daily injections of 10 micrograms EB Day 1 through Day 5, or a single injection of 100 micrograms EB on Day 3, the incidence of the PD pattern was high at 41-60 days of age, but later the PD-type was replaced by the PE pattern of vaginal smears. In the rats that were treated with 5 daily injections of 10 micrograms EB from Day 1 through Day 5 and were ovariectomized on Day 22, a slight but significant increase in the level of luteinizing hormone in plasma was noted after administration of EB and progesterone on Day 100 but not on Day 50. These results indicated that neonatal injections of EB induce sterility, but the effect is dependent on the amount of EB injected and length of time over which the injections are given.(ABSTRACT TRUNCATED AT 250 WORDS)     

Regulatory mechanisms to control tissue alpha-tocopherol

To test the hypothesis that hepatic regulation of alpha-tocopherol metabolism would be sufficient to prevent overaccumulation of alpha-tocopherol in extrahepatic tissues and that administration of high doses of alpha-tocopherol would up-regulate extrahepatic xenobiotic pathways, rats received daily subcutaneous injections of either vehicle or 0.5, 1, 2, or 10 mg alpha-tocopherol/100 g body wt for 9 days. Liver alpha-tocopherol increased 15-fold in rats given 10 mg alpha-tocopherol/100 g body wt (mg/100 g) compared with controls. Hepatic alpha-tocopherol metabolites increased with increasing alpha-tocopherol doses, reaching 40-fold in rats given the highest dose. In rats injected with 10 mg/100 g, lung and duodenum alpha-tocopherol concentrations increased 3-fold, whereas alpha-tocopherol concentrations of other extrahepatic tissues increased 2-fold or less. With the exception of muscle, daily administration of less than 2 mg/100 g failed to increase alpha-tocopherol concentrations in extrahepatic tissues. Lung cytochrome P450 3A and 1A levels were unchanged by administration of alpha-tocopherol at any dose. In contrast, lung P-glycoprotein (MDR1) levels increased dose dependently and expression of this xenobiotic transport protein was correlated with lung alpha-tocopherol concentrations (R(2)=0.88, p<0.05). Increased lung MDR1 may provide protection from exposure to environmental toxins by increasing alveolar space alpha-tocopherol.     

Effect of non-aromatizable androgens on testicular and accessory gland functions in rhesus monkeys (Macaca mulatta)

Adult male rhesus monkeys were injected intramuscularly 100 micrograms, 1000 micrograms 5 alpha-androstane-3 alpha, 17 beta-diol or 100 micrograms dihydrotestosterone (DHT) per day for 70 days. A decrease in seminiferous tubular diameter was seen in treated animals. Androstanediol treatment disrupted spermatogenesis in most tubules. Sperm motility decreased within 40 days and by Day 70 non-motile spermatozoa were seen in 2 animals of each group treated with androstanediol. DHT treatment also decreased sperm motility progressively from Day 40. Both androgens caused retention of the cytoplasmic droplet and an increase in coiling of the tail of spermatozoa. Seminal fructose was decreased by Day 40 (1000 micrograms androstanediol) or Day 70 (100 micrograms androstanediol and 100 micrograms DHT). Seminal glycerophosphocholine (GPC) and acid phosphatase levels decreased by Day 70 in all treatment groups. Both steroids decreased circulating concentrations of testosterone without altering FSH or oestradiol values.     

Effects of steroid administration on pituitary luteinizing hormone and follicle-stimulating hormone in ovariectomized pony mares in the early spring: pituitary responsiveness to gonadotropin-releasing hormone and pituitary gonadotropin content

These experiments tested the hypothesis that administration of steroid hormones to ovariectomized (OVX) mares during the vernal transition to the breeding season would influence LH and FSH secretion. Circulating gonadotropin concentrations, response to exogenous GnRH, and pituitary gonadotropin content were monitored. Experiments 1 and 2 were conducted, beginning 10 March, and 3 February, respectively, utilizing a total of 30 long-term OVX pony mares. In experiment 1, mares were administered vehicle (n = 5) or estradiol-17 beta (E2, n = 5, 5 mg/3 ml sesame oil), twice daily for 16 days. Blood samples were collected daily for assessment of circulating LH and FSH concentrations. On Day 10 of treatment, 400 micrograms GnRH were administered to all mares. LH increased significantly over days of treatment in the estradiol-treated group, but pituitary response to GnRH tended to be less than in control mares. Circulating FSH tended to decline over days of treatment in estradiol-treated mares, and the pituitary response to GnRH was significantly reduced. Pituitary LH, but not FSH, was increased on Day 16 of treatment with estradiol. In experiment 2, 20 OVX mares received, twice daily, vehicle (n = 5), E2, n = 5; 5 mg), progesterone (P4, n = 5; 100 mg), or progesterone plus estradiol (P4/E2, n = 5; 100 + 5 mg). Treatment continued for 14 days. GnRH (100 micrograms) challenges were administered on Days 6 and 13 of treatment.(ABSTRACT TRUNCATED AT 250 WORDS)     

Comparative study of blocking effects of various retinoids on the occurrence of permanent proliferation of vaginal epithelium in mice treated neonatally with estrogen

Neonatal injections of 20 micrograms 17 beta-estradiol (E2) induced persistent proliferation and cornification of the vaginal epithelium in adult ovariectomized C57 Black/Tw mice. However, permanent vaginal changes were prevented by various retinoids when, simultaneously with E2 treatment, the animals were given injections of 100 micrograms daily dose of retinol, retinol acetate, retinal or of 200 micrograms daily dose of retinol palmitate (RoP). Neonatal injections of a 100 micrograms daily dose of RoP had no preventive effect on the occurrence of E2-induced permanent vaginal changes. This finding suggests that the preventive effect of RoP is weaker than that of other retinoids showing approximately the same degree of prevention. Combined treatment with E2 plus retinoic acid (even a small dose of 20 micrograms) had such a toxic effect on newborn mice that they died within 7 days after birth, while the animals given neonatal injections of 20 micrograms retinoic acid alone survived until the termination of the experiment.     

Hormone responses to low-dose GnRH treatment in post-partum beef cows

Acyclic beef cows received 1.0, 2.5 or 5.0 micrograms GnRH/2 h for 48 h as 24 X 2 h repeated i.v. injections or by continuous i.v. infusion. Preovulatory-type LH surges were detected in 9/18 injected and 8/15 infused cows and occurred 30.6 +/- 5.1 h and 3.3 +/- 0.7 h after the start of treatment respectively. Cows receiving the lowest infusion dose did not exhibit gonadotrophin surges. The LH response to individual injections increased with dose but the proportion of injected cows showing preovulatory-type surges at each dose level did not change. A total of 20 cows (10 injected and 10 infused) showed evidence of luteal activity within 7 days of the end of GnRH treatment, although this was transitory in most animals. Cows which exhibited preovulatory-type LH surges in response to treatment had significantly higher plasma oestradiol-17 beta concentrations and lower FSH concentrations before treatment than those which did not. The results suggest that the LH response to GnRH treatment is dependent on follicular status in the immediate pretreatment period.     

Age and thyroid hormone as factors in the responses of BHE rats to starvation-refeeding

The interacting effects of thyroid hormone, age, and duration of starvation on the enzyme and liver lipid responses of BHE rats to starvation-refeeding were studied. Rats were starved for 2, 4, or 7 days and refed a 65% glucose diet for 2 days. The rats were either 150 or 420 days of age and injected daily with either saline or 10 micrograms thyroxine/100 g body weight. Neither age nor duration of starvation affected the glucose-6-phosphate dehydrogenase or malic enzyme activity or liver lipid response to starvation-refeeding. However, thyroxine treatment potentiated the response to starvation-refeeding in the 420-day-old rats when the duration of starvation increased from 2 to 7 days.     

Two daily melatonin injections differentially induce nonshivering thermogenesis and gonadal regression in the mouse (Peromyscus leucopus)

Female white-footed mice (Peromyscus leucopus) were injected twice daily with 5, 10, 50, 100 micrograms melatonin (MEL) or saline. Injections were given for 7 weeks at 2 and 12 hours after lights-on under a long day (LD 16:8) photoperiod. Afternoon administration of MEL induced gonadal regression, although a dose of 50 micrograms or more was necessary to obtain a maximal response. A 5 micrograms MEL injection in the afternoon resulted in intermediate reproductive tract weights. In white-footed mice a morning MEL injection did not abolish the reproductive regression induced by an afternoon injection. Mice receiving 10, 50 or 100 micrograms MEL daily exhibited increased nonshivering thermogenesis (NST), irrespective of the timing of the injection. Daily injections of 5 micrograms MEL had little effect on NST. These observations suggest that "up and down regulation" of MEL receptors may not be important in P. leucopus. Further, the mechanism by which MEL controls reproduction is different from that for NST.     

Effect of ovine trophoblast protein-1, oestrogen and progesterone on oxytocin-induced phosphatidylinositol turnover in endometrium of sheep

In Exp. 1, endometrium was collected from Day-15 cyclic ewes and effects of oTP-1, oxytocin and oTP-1 + oxytocin, in various temporal relationships, on phosphatidylinositol (PI) turnover were determined. Co-treatment of endometrium with oTP-1 and oxytocin inhibited stimulatory effects of oxytocin, while treatment with oTP-1 before and during oxytocin administration had no effect. Turnover of PI was unaffected by oTP-1 alone. In Exp. 2, ovariectomized ewes were treated with progesterone (50 mg/day) for 10 days and then oestrogen (100 micrograms/day) for 2 days and endometrium was collected. Oxytocin stimulated PI turnover in endometrium, but oTP-1 had no effect alone or in combination with oxytocin. In Exp. 3, ovariectomized ewes were treated with corn oil (1 ml/day), oestrogen (50 micrograms/day), progesterone (50 mg/day) or progesterone + oestrogen for 10 days and endometrium was collected. Oxytocin stimulated PI turnover only in ewes that received progesterone. oTP-1 alone had no effect on PI turnover, while co-treatment of endometrium with oxytocin and oTP-1 stimulated PI turnover in ewes treated with progesterone, but not progesterone and oestrogen. Pretreatment of endometrium with oTP-1 stimulated PI turnover when ewes were treated with progesterone or progesterone + oestrogen. Pretreatment of endometrium with oxytocin and then treatment with oTP-1 inhibited PI turnover compared to treatment with oxytocin alone. In Exp. 4, ovariectomized ewes were treated as in Exp. 2. Catheters were placed into the uterine horns and ewes received oTP-1 into one horn and serum into the other twice daily on Days 10-12 of steroid treatment. Endometrium collected on Day 13 was used to measure PI turnover and received either no treatment or oxytocin. Oxytocin stimulated PI turnover in endometrium of these ewes and in-vivo treatment of the ewes with oTP-1 had no effect on PI turnover. These results indicate that antiluteolytic effects of oTP-1 are not mediated by inhibiting effects of oxytocin on phosphatidylinositol turnover if oxytocin receptors are present and that uterine responsiveness to oxytocin is progesterone dependent.     

Gonadotropins and sex hormones modulate interrenal function in soft-shelled turtle

The aim of the current work was to investigate the role of gonadotropins and female sex hormones on interrenal activity in soft-shelled turtles, Lissemys punctata punctata. 1) FSH treatment (3 microg/100 g body wt daily for 10 days) caused interrenal hypertrophy with increased nuclear diameter, raises of acid phosphatase and alkaline phosphatase concentrations, and depletions of cholesterol (except the free fraction) and ascorbic acid levels from the interrenal gland. However, LH treatment (3 microg/100 g body wt daily for 10 days) failed to produce any perceptible change in the interrenal activity. The combined treatments of FSH and LH (3 microg each/100 gm body wt daily for 10 days) produced no further change beyond that of FSH alone. 2) Estrogen treatment with the low dose (25 microg/100 g body wt daily for 10 days) had no effect, but with higher doses (50 microg or 100 microg/100 gm body wt daily for 10 days) is caused interrenal stimulation by inducing the same manifestations to those of FSH. The degree of manifestations was higher with the higher dose (100 microg daily) than that of the moderate dose (50 microg daily). Progesterone treatment with the low dose (25 microg /100 g body wt daily for 10 days) had no significant effect, but with the moderate (50 microg daily) and higher (100 microg daily) doses suppressed interrenal activity by showing the reverse changes to those of estrogen. The degree of manifestations was higher with the higher dose than that of the moderate one. The combined treatments of estrogen and progesterone (100 microg each/100 g body wt daily for 10 days) caused interrenal stimulation but to a lesser extent than that of estrogen alone. The findings are briefly discussed.     

Plasma concentrations of gonadotrophins, preovulatory follicular development and luteal function associated with bovine follicular fluid-induced delay of oestrus in heifers

In Exp. 1, injections of 10 ml bovine follicular fluid (bFF, i.v. or s.c.), given twice daily for 3 days after injection of a luteolytic dose of PGF-2 alpha, delayed the onset of oestrus in 3 of 6 heifers to 8 or 9 days after PGF-2 alpha, as compared with 2 or 3 days after PGF-2 alpha in control heifers. Mean plasma concentrations of FSH and LH during the injection period were not different from those in saline-injected heifers. In Exp. 2, i.v. injections of 20 ml bFF twice daily for 3 days uniformly delayed oestrus to 8 days after PGF-2 alpha (N = 4) and injections of 20 ml bFF i.v. every 6 h for 24h on the day of PGF-2 alpha injection delayed oestrus to 5.0 +/- 0.6 days after PGF-2 alpha as compared with 2.8 +/- 0.3 days for control heifers. In both treatment groups, plasma concentrations of FSH were suppressed during the injection period and increased transiently after treatment, but plasma concentrations of LH during the injection period were not different from those of control heifers. Plasma levels of oestradiol in heifers given bFF remained basal for 2 or 3 days after treatment, then increased several days before the delayed oestrus, in a manner similar to that in control heifers, and elicited normal preovulatory surges of LH and FSH. Plasma concentrations of progesterone and the length of the next oestrous cycle were normal, indicating formation of functional corpora lutea. Therefore, bFF treatments appear to delay oestrus by selectively suppressing plasma FSH, without affecting LH, and delaying the development of the preovulatory follicle. These results suggest that FSH may be critical to support the growth and development of the preovulatory follicle after luteolysis in cows.     

Action of PGI2 analogs on the pulmonary and systemic circulations in the conscious newborn lamb

Previous work (Lock et al., J. Pharm . Exp. Ther. 215:156, 1980) has shown that conventional screening procedures for vasoactive PGI2 analogs were little value in predicting pulmonary vasodilator activity in the newborn lamb. To gain a better insight into the structural requirements for pulmonary vasoactivity and possibly identify useful compounds for the management of neonatal pulmonary hypertensive disorders, we have tested the following PGI2 analogs in normoxic and hypoxic newborn lambs: 15(S)-9-deoxy-15-methyl-9 alpha,6- nitrilo -PGF1 (analog I); 9-deoxy-9 alpha,5- nitrilo -PGF1 (analog II); (6S, 15S)-15-methyl-PGI2 (analog III); and ( 6R , 15S)-15-methyl-PGI1 (analog IV). A prostaglandin analog mimicking PGI2 (compound BW245C ; (+/-)-5-(6- carboxyhexyl )-1-(3-cyclohexyl-3-hydroxypropyl)hydantoin ) was tested as well. Compounds were injected into a branch pulmonary artery and any local pulmonary effect could be assessed from the change in the ratio of blood flow to the injected lung over total flow. None of the analogs tested proved to be a selective pulmonary dilator. BW245C was a potent peripheral vasodilator (threshold around 0.5 microgram/kg) and indirectly lowered pulmonary vascular resistance through its systemic effects. Analog I also dilated the systemic circulation, but only at the highest dose tested (100 micrograms/kg). The latter finding is surprising because it was previously shown that the parent, non-methylated compound is a fairly potent and selective pulmonary vasodilator. Analog II and IV were inactive at a dose up to, respectively, 30 and 20 micrograms/kg. Analog III, on the other hand, weakly constricted the systemic circulation at a dose of 10 micrograms/kg.(ABSTRACT TRUNCATED AT 250 WORDS)     

Differences in potential and content of the mucus in the stomach of the rat with avitaminosis A

Vitamin A (vit. A) acts in the synthesis of glycoproteins and in cell surface phenomena of epithelia. Since the glycoproteins of gastric mucus and the integrity of gastric cell membranes are components of gastric barrier (GB), vit. A could play a role in GB. Five groups of rats were used: I) rats fed on vit. A deficient diet; II) rats pair-fed plus a daily oral dose of 45 micrograms vit. A; III) normal rats; IV) rats recovered from avitaminosis A (avit. A) after 20 days of daily oral dose of 300 micrograms vit. A; V) rats pair-fed plus a daily oral dose of 45 micrograms vit. A. We measured: 1) transparietal gastric potential difference (PD) in vivo (by means of agar-KCl electrodes); 2) mucus (by binding of Alcian blue): in gastric mucosa; adherent to gastric mucosa; in gastric lumen; 3) dry weight of the stomach. Avit. A induced: i) a decrease of PD and mucus in mucosa and lumen; ii) an increase of mucus adherent to mucosa; iii) an increase of the percentage of dry weight on wet weight. All parameters were normal after recovery from avit. A. Results suggest that avit. A could reduce either mucus synthesis or its erosion. Moreover avit. A might modify mucus structure and sterical configuration of mucosal cells. The alteration of mucosal cell membranes could decrease PD. In conclusion the modifications of some components of rat GB seem specifically caused by avit. A and suggest a protective role of vit. A.     

Treatment of experimental disseminated Mycobacterium avium complex infection in mice with recombinant IL-2 and tumor necrosis factor

Mycobacterium avium complex (MAC) is the most common bloodstream pathogen isolated from patients with AIDS. We have previously shown that TNF alone or in combination with IL-2 can activate human and murine macrophages in vitro to kill MAC strains isolated from disseminated infections. To determine whether treatment with TNF and IL-2 could effect the course of disseminated MAC infections in a murine model of disseminated MAC infection, we infected C57BL mice with 3 x 10(8) bacteria i.v. and 1 wk later administered: 1) IL-2, 100 micrograms/kg; 2) TNF, 25 micrograms/kg; 3) IL-2, 50 micrograms/kg, and TNF, 12.5 micrograms/kg; and 4) saline. IL-2 was injected i.p. daily with TNF being administered in cycles of 3 out of 4 consecutive days. Fourteen days after starting therapy, blood was cultured and mice were sacrificed for quantitative cultures of liver and spleen homogenates. IL-2, TNF, and IL-2/TNF treated groups showed an 87 +/- 5%, 57 +/- 9%, 88 +/- 6% decrease in bacteremia (p = 0.05 for TNF-treated animals and less than 0.04 for the other two groups, compared with control). The combination IL-2/TNF was the only treatment that showed a trend toward an absolute decrease in the number of bacteria in the blood. Reduction in colony counts of liver and spleen were 77 +/- 4% and 87 +/- 6%, respectively, for treatment with IL-2, 58 +/- 7% and 87 +/- 5% for TNF, and 60 +/- 10% and 82 +/- 6% for IL-2/TNF, respectively. These results suggest that both cytokines may play a role in the control of Mycobacterium avium infection and that the combination of a half-dose of IL-2 and TNF, despite not showing any greater efficacy, can be less toxic than TNF or IL-2 alone and might be useful for the therapy of disseminated infection.     

Relationship between insecticide-induced short and wry neck and cervical defects visible histologically shortly after treatment of chick embryos

In order to clarify the anatomical precursor of short and wry neck, 48-hr chick embryos were injected with 6.25-200 micrograms of the organophosphate (OP) insecticide diazinon and recovered either at 96 hr for histological evaluation or at 19 days for gross observation. Among embryos recovered at 96 hr, all receiving a dose of 25-200 micrograms showed, in serial cross sections, the cervical notochord severely folded in the vertical, horizontal, and diagonal planes and the adjacent neural tube variously folded (often with branching of its canal), deformed by the notochord, rotated, and/or displaced from the midline. Virtually all embryos injected with 6.25 or 12.5 micrograms were fully free of such abnormalities. The coinjection of 2-pyridinealdoxime methochloride (2-PAM, which protects the embryo from certain OP insecticide-induced teratisms) along with 200 micrograms of diazinon markedly reduced the notochord and neural wry neck at 19 days paralleled the 96-hr cervical histology: pronounced in all embryos receiving greater than or equal to 25 micrograms, virtually nonexistent in those receiving 6.25 or 12.5 micrograms. Though more marked at higher doses, wry neck occurred to varying extents at all doses, 6.25-100 micrograms. We conclude that 1) the primary insecticide effect is upon the notochord rather than the neural tube, 2) short neck is a direct consequence of notochord folding, 3) wry neck is apparently not linked with notochord folding, and 4) vertebral fusion is not the consequence solely of muscle paralysis as argued elsewhere. We propose that the notochord folds because diazinon disrupts normal formation of its sheath.