Evaluation of environmental support in group homes for persons with mental retardation.

Types of environmental support provided to adults with mental retardation in group homes after transfer from a large state institution were compared. Substantial differences in the functioning of the group homes were found even though the service structure was held constant. Community adjustment was compared for matched groups of residents of the group homes. Differences in community adjustment occurred for residents in group homes with significantly different functional features. The findings indicate that resident outcome was generated by the interaction of several factors in combination. Both structural and functional features of facilities must be considered in any evaluation of the effectiveness of community programs.

Role of endogenous opiates in the modulation of gonadotropin secretion in infant monkeys (Macaca mulatta): effects of naltrexone.

A potential inhibitory role of endogenous opioids in the gonadotropin decline from infancy to the prepubertal period in primates was assessed by examining the effect of the specific opioid antagonist naltrexone on gonadotropin levels in infant rhesus monkeys. Paradoxically, both chronic administration of naltrexone to neonatally castrate males as well as acute administration of graded doses to intact infant females resulted in gonadotropin suppression compared to appropriate vehicle-treated controls. Thus, naltrexone behaves as a gonadotropin secretory antagonist in infant monkeys and cannot be used to unmask a putative inhibitory mechanism involving endogenous opiates.

Gonadotropin responsiveness to estrogens and low-level progesterone in the ovariectomized rhesus monkey.

When estrogen is administered to gonadectomized rhesus monkeys in sufficient quantity, luteinizing hormone (LH) and follicle-stimulating hormone (FSH) levels are initially suppressed and gonadotropin secretion is subsequently augmented. This study was designed to examine the ability of various orally administered estrogens to elicit biphasic pituitary responses in adult castrate rhesus monkeys and to investigate the role of low-level progesterone in altering these responses. In an incomplete block design, 13 treatments were constructed: (E2): 0.5, 5.0, 50 micrograms/kg; (DES): 0.05, 0.5, 5.0 micrograms/kg; zearalenone (Z): 10, 100, 1000 micrograms/kg; or oil vehicle, each combined with progesterone. The remaining treatments (5.0, 0.5, and 100 micrograms/kg of E2, DES, and Z, respectively) did not include progesterone. During six intervals, E2, DES, or Z was administered orally on Days 1, 2, and 3 and blood was sampled on Days 0, 3, and 8 of each period. A main effect of estrogen treatment was observed for LH and FSH secretion on Day 3 but not Day 8. There was no main effect of progesterone alone on release of either LH or FSH on days 3 or 8, nor were significant carry-over effects of progesterone, E2, DES, or Z on LH or FSH concentration apparent by Day 8 of any treatment. However, progesterone synergized with E2 to suppress Day 3 LH levels. Conversely, DES and Z interacted with progesterone to facilitate LH secretion at this time.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of zearalenone on various components of rabbit uterine tubal fluid.

A study was conducted to determine whether an orally administered mycotoxin, zearalenone (11.5 mg/kg of body weight/day), enters the uterine tubal fluid (UTF) of rabbits and to evaluate its influence on certain constituents of UTF. Using high-performance liquid chromatography, the concentration of zearalenone in UTF was maximal on day 1 of initial exposure to the compound, then decreased rapidly to half the peak concentration by day 5. The disappearance curve for zearalenone in UTF was linear throughout the treatment period (10 days) and was not detectable within 3 days after the last administration of zearalenone and the initiation of pregnancy (does were bred on day 10 of the zearalenone treatment). Zearalenone increased the volume of UTF (P less than 0.05) in estrous does, but decreased the pH (P less than 0.05) and the total free amino acid concentration (P less than 0.05) of UTF, compared with pretreatment values. The concentrations of several trace elements and amino acids known to be of critical importance in early embryonic development were altered by zearalenone treatment and/or pregnancy. Gross developmental anomalies were not evidenced when fetuses were examined on days 28 to 30 of gestation. It was concluded that zearalenone or associated metabolites affect factors that influence fertility during the early preimplantation period. Furthermore, the analysis of UTF appears to be an effective screening method for assessing certain potential reproductive toxicants.

The postweaning rise of tonic luteinizing hormone secretion in anestrous cows is not prevented by chronic milking or the physical presence of the calf.

The objective of the following study was to examine the ability of frequent milking, the physical presence of the calf, and their combination to prevent a postweaning rise in tonic luteinizing hormone (LH) secretion, estrus, and ovulation. Thirty Hereford cows were allowed to suckle their calves ad libitum until 17-21 days post partum and confirmed as anestrus. They were then assigned alternately by order of calving to 1 of 5 treatment groups: (1) Suckled (S) ad libitum; (2) Nonsuckled (NS)--calf removed for 102 h; (3) Nonsuckled--calf present (NSC)--calf remained with cow, but muzzled to prevent suckling for 102 h; (4) Nonsuckled--milked 8 times a day (NSM)--calf removed for 102 h and cow hand-milked for 10 min every 2 h from 0700 to 2100 h; (5) Nonsuckled--calf present--milked 8 times a day (NSMC)--combination of 3 and 4. Luteinizing hormone secretion patterns, estrous activity, and ovulation were monitored throughout the experiment. Prior to treatment (Day 0), mean pulse frequency (pulses/6 h), mean concentrations (ng/ml), and median concentrations (ng/ml) of LH did not differ (p greater than 0.45) between groups, and were 0.7 +/- 0.15, 2.8 +/- 0.14, and 2.6 +/- 0.11, respectively. Marked rises (p less than 0.01--p less than 0.03) in LH pulse frequency were observed in all groups except S between 48 and 54 h after onset of treatment. Mean and median concentrations of LH were lower (p less than 0.02) in S cows than in all other groups at 48-54 h.(ABSTRACT TRUNCATED AT 250 WORDS)

A preliminary communication. Isolation and positive confirmation of chlordecone in rabbit oviductal fluid.

Chlordecone (10 mg/kg, sc in corn oil) was administered to mature female rabbits once daily for five days. Analysis of oviductal fluid collected from these rabbits over the course of this experiment confirmed the presence of chlordecone. It is reasonable to suggest that chlordecone may reduce mammalian fertility during the preimplantation period by producing deleterious effects on respective gametes and/or the embryo. The mechanisms by which chlordecone may interfere with fertilization and reproduction is discussed.