Environmental education for all engineers.

Environmental engineering education at universities is a rapidly changing field globally. Traditionally it has resided in the civil engineering program addressing water and wastewater quality, treatment, design and regulatory issues. In recent years environmental engineering has become a much broader field encompassing water, wastewater, soil pollution, air pollution, risk assessment, ecosystems, human health, toxicology, sustainable development, regulatory aspects and much more. The need to introduce environmental engineering/green engineering/pollution prevention/design for the environment concepts to undergraduate engineering students has become recognized to be increasingly important. This need is being driven in part through the US Engineering Accreditation Commission Accreditation Board for Engineering and Technology criteria 2000. Thus there has been a major shift in environmental engineering education and it no longer resides only within the civil engineering discipline. This paper focuses on the development of innovative curricula for a brand new engineering program at Rowan University that integrates environmental education for all engineers. A common course known as "engineering clinic" was developed for all engineering students throughout their eight semesters of engineering education. One of the clinic goals is to integrate engineering design and the environment. The program, in its seventh year, indicates successful implementation of environmental education in all four engineering disciplines in their course work and clinics.

Neurobiology of reproduction in the female rat. A fifty-year perspective.

With respect to the ovarian status and the estrous cycle as expressed by the vaginal cytology, it was emphasized that there is only a rough correspondence between the vaginal stages and the days of the cycle. The 4-day cycle tends to be the most frequent, with the 5-day cycle a normal variant. Spontaneous persistent vaginal estrus (SPE), an acyclic state occurring in older adult rats, reflects the presence in the ovaries of large vesicular follicles failing to luteinize and, hence, the absence of corpora lutea once the condition becomes well established. Pseudocyclic fluctuations in the vaginal smear during SPE resemble those in ovariectomized rats treated chronically with estrogen. The age of onset of SPE varies among different rat strains, appearing as early as 5 or 6 months in the DA and CD strains, but rarely before 12 months in the O-M strain. O-M/DA hybrids were intermediate. In the DA strain there was also a marked influence of length of daily illumination on the occurrence of SPE: exposure to 10 hours or less of light per day restored cycling to rats that had already shown SPE while exposed to longer days. An hereditary influence of age was also apparent in the rapidity with which continuous illumination induced persistent estrus (LLPE). Young DA females rapidly entered LLPE within 10 days, while young O-M females remained cyclic for 5 weeks. Hybrids again were intermediate. At middle age. O-M rats became as responsive as young rats of the DA strain. Like SPE in DA rats. LLPE was reversible, for estrous cycles returned after daily exposure to light was reduced. The special sensitivity of DA rats to lighting may have been a trait acquired from outcrossing with wild gray rats in years past. Normal cycling could be restored in SPE rats by daily injection of progesterone at low dosage. The same effect followed isolated treatments with progesterone upon return of proestrus/estrus after interruption of SPE. This was the first demonstration of positive feed-back of progesterone, the first sign of its biphasic action, and an indication that progesterone facilitates the action of estrogen in promoting ovulation. When progesterone treatment was delayed after proestrus/estrus there was progressively lower effectiveness during the next 10 days. Indirect support of regular ovulatory cycles resulted from treating DA SPE rats with prolactin (PRL) daily at low doses, provided that an initial set of corpora lutea was first induced by other means.(ABSTRACT TRUNCATED AT 400 WORDS)

Further study of oestrous cycles that follow interruption of spontaneous persistent oestrus in middle-aged rats.

Spontaneous persistent oestrus in certain middle-aged rats, when interrupted by an injection of LH, is usually followed by one or more short ovulatory cycles. A previous study disclosed that brief treatment with bromocriptine early in dioestrus blocks completion of the initial cycle whereupon persistent oestrus promptly returns, indirect evidence that the cycles are sustained through low-grade activation of the corpora lutea by prolactin. Further evidence of this is now presented by demonstration that administration of extrinsic prolactin at the time of the bromocriptine injection overcomes the blockage, apparently rescuing the corpora lutea and allowing completion of the cycle with renewed luteinization. Whereas bromocriptine treatment shortens the current dioestrus, the added prolactin restores the duration to at least that shown by 'LH-only' controls. In a related experiment, when persistent oestrus was interrupted by an injection of phenobarbitone (without corpus luteum formation), most of the rats remained dioestrous for only 2 days. In a few rats, this was followed by spontaneous completion of an ovulatory 4-day cycle. Hence, in the 'LH-only' group the small number of 4-day cycles may actually have gone to completion without dependence on the original set of corpora lutea. In some of the 'LH-only' group, a possible relationship was examined between the prolactin level at the time of LH injection and the subsequent ability of the rat to sustain multiple cycles.(ABSTRACT TRUNCATED AT 250 WORDS)

Comparable surges of luteinizing hormone induced by preoptic or medial basal tuberal electrical stimulation in spontaneously persistent estrous or cyclic proestrous rats.

A previous report demonstrated in cyclic proestrous rats electrically stimulated in the medial preoptic area (MPOA) or the arcuate nucleus-median eminence (ARC/ME) region a close parallel in the progressive increase of serum LH with increasing stimulation time. The present report compares the LH surges induced in middle aged spontaneously persistent estrous (SPE) rats by electrical stimulation of the two regions. Electrical parameters were those previously used. In Series I, MPOA stimulation of SPE rats for 60 min or ARC/ME stimulation for 45 min produced serum LH concentrations 60 and 90 min after stimulation began that were essentially identical to those in proestrous rats similarly treated. In Series II, stimulations were prolonged to 120 min to determine whether LH would continue to rise with the longer stimulation. These rats were all chosen from one shipment and all were born on the same day. Sequential blood samples were taken before stimulation and 60, 90, 120, and 150 min after stimulation began. SPE rats were stimulated in either the MPOA or the ARC/ME and, for comparison, a few proestrous rats that had remained cyclic were stimulated in the MPOA. LH concentrations in these cyclic rats rose more abruptly than in the previous study to amounts significantly higher at both 60 and 90 min, but by 120 min the respective means were not significantly different. In the SPE rats, the 60-min LH levels resembled those in Series I. They continued to rise during the second hour, but only to average levels approximately half those attained in proestrous rats stimulated for 120 min. The comparative increments in MPOA-stimulated and ARC/ME-stimulated rats were similar, although all means in the latter were somewhat higher. The results agree with previous indications that stimulation of either the MPOA or the ARC/ME activates the rostral or caudal portions of a unitary preoptic-tuberal system. Although the tendency of SPE rats to release smaller amounts of LH may result from age-related lowered pituitary responsiveness to LHRH, only future study can determine whether a given degree of preoptic-tuberal stimulation releases equivalent amounts of LHRH in SPE and proestrous rats. Nevertheless, the absence of spontaneous LH surges in SPE points to a primary deficiency in control mechanisms impinging on the preoptic-tuberal system or in its responsiveness thereto.

Similarity of luteinizing hormone surges induced by medial preoptic stimulation in female rats blocked with pentobarbital, morphine, chlorpromazine, or atropine.

Adult proestrous rats were subjected to either electrochemical or electrical stimulation of the medial preoptic area after ovulation-blocking dosage with either pentobarbital (PTBL), morphine, chlorpromazine, or atropine. For electrochemical stimulation (ECS), 233 microA anodal DC for 30 sec (7000 mu coulombs) was delivered through a unipolar stainless steel electrode. For electrical stimulation (ES), 750 microA biphasic pulse pairs at 30 Hz, on and off each 15 sec, were delivered through a coaxial platinum electrode, in four 5-min bursts equally spaced during 60 min. In PTBL-blocked rats this stimulus produced LH surges equivalent to those after continuous stimulation for 60 min. Blood was collected 60 and 90 min after ECS or after the start of ES. Mean serum LH concentrations (RIA) maximal at 90 min after ECS, were similar under the four blocking agents (1270-1486 ng/ml serum in terms of NIAMDD LH RP-1). Like-wise, after ES there were no significant differences (P greater than 0.05) among the mean LH levels at 60 min (310-571 ng/ml serum). The 90-min values showed a downward, but not significant, trend in the case of PTBL, chlorpromazine, and atropine plus PTBL. Under morphine an apparent upward trend was due largely to an animal having an especially large increase. With rare exception, full ovulation was evident at terminal laparotomy on the morning after stimulation. Thus, whichever of the several drugs was used, medical preoptic area stimulation with given parameters induced section of comparable amounts of LH. None of the drugs appears to have primary suppressive action on the preoptic-tuberal system, on the availability of LHRH or its release into the portal vessels, on the ability of the pituitary to release LH, or on the ovarian response.

Comparison of luteinizing hormone surge responses to ovarian steroids in cyclic and spontaneously persistent estrous rats of middle age.

Female rats of the Charles River CD strain, when 6 to 12 months old, present spontaneous persistent estrus (SPE) in increasing numbers, while others remain cyclic. Apparently as a prelude to SPE, some rats still cycling will fail to ovulate early in response to estrogen or progesterone administration during diestrus. When estradiol benzoate (EB) was given on Day 2 of the 5-day cycle or when progesterone was given on Day 3, the luteinizing hormone (LH) surges, if they occurred at all, tended to be much smaller than the normal surge of proestrus. The normal surges could be equalled only when EB was given on Day 2 and followed by progesterone on Day 3. In SPE rats, progesterone treatment usually induces ovulation only after SPE has been interrupted for a few days and the rat has returned to proestrus-estrus. LH surges induced in that way by progesterone were usually substantial. Thus, the ability of the LH-release apparatus to function had returned within 1 week after interruption of the persistent estrogenic status. Comparison were made of LH surge responses to EB administration in cyclic and SPE rats during pseudopregnancies produced by cervical stimulation (after LH injection of SPE rats) or by daily injection of progesterone. In previously cyclic rats, proestrus-like surges of LH were registered consistently, while in previously SPE rats the levels attained were generally lower. Unexpectedly, if rats were castrated when daily progesterone treatment started, few produced large amounts of LH. This was especially true in the SPE group, 14 of 20 rats failing to show any LH surge. Hence, although capacity to produce the LH surge in response to estrogen + progesterone can return within a few days after SPE cases, some unknown ovarian activity plays an important role. Such activity may also take part in the normal cycle.

Delta 9-tetrahydrocannabinol suppression of prolactin secretion in the rat: lack of direct pituitary effect.

The effects of (--)trans-delta 9-tetrahydrocannabinol (THC) on tonic PRL secretion were investigated in long term ovariectomized or hypophysectomized/pituitary-autografted female rats and in flask incubations of anterior pituitary tissue. Intravenous injection of 0.25-8.0 mg THC/kg BW into ovariectomized rats markedly suppressed serum PRL 60 min later relative to control PRL levels. In a second experiment, ovariectomized rats bearing intraatrial cannulae were injected with 0.5 mg THC/kg BW, iv, and serial blood samples were drawn. PRL was significantly suppressed at 10 min, with persistence of the suppression for the duration of the 70-min sampling period in this time-course study. In contrast, the administration of 1.0 mg THC/kg BW, iv, to hypophysectomized/pituitary-autografted female rats failed to influence PRL secretion throughout a 120-min posttreatment sampling period. The apparent inability of THC to directly suppress PRL release from pituitary tissue was further studied by in vitro flask incubations of anterior pituitary tissue. Although a 1-h exposure of rat anterior pituitary tissue to bromocryptine (CB-154; 2.2 X 10(-4) M) suppressed subsequent PRL release, similar exposure to 10(-6) or 10(-4) M THC had no influence. The failure of THC to alter tonic PRL secretion in hypophysectomized/pituitary-autografted rts or PRL release from pituitary tissue in vitro strongly suggests that the central nervous system rather than the pituitary is the site of THC action in the acute suppression of tonic PRL secretion.

Luteinizing hormone requirements for ovulation in the pentobarbital-treated proestrous rat.

The LH requirements for ovulation in the pentobarbital-blocked proestrous CD rat have been studied by increasing serum gonadotropin levels through electrical stimulation of the brain and subsequently comparing the effects of timed hypophysectomy on ovulation and serum LH concentrations. The arcuate nucleus (ARC) or the medial preoptic area (POA) was stimulated unilaterally for 45 min with matched pairs of biphasic rectangular pulses through a coaxial platinum electrode. Serum LH was significantly elevated above basal values at the end of stimulation, but not in sham-stimulated controls. The results of both hormone measurement and hypophysectomy showed that the pituitary continued to release LH after extrinsic stimulation of the hypothalamus had ceased. Animals did not ovulate if they had been hypophysectomized at the end of the 45 min stimulation whereas nearly all ovulated if hypophysectomy was delayed for an additional 20 min. Some evidence suggested that the pituitary could be removed earlier without affecting ovulation if the rate of LH release was increased. The minimum peak LH concentration measured in rats that subsequently ovulated fully was 187 ng/ml, substantially lower than concentrations ordinarily attained in the spontaneous proestrous surge. When serum LH was insufficiently high to cause follicle rupture, there was nevertheless the resumption of meiosis and luteinization of the large ovarian follicles. Attempts were made to restore ovulability in animals presumed to have released a subovulatory quota of gonadotropin. Ovulation was obtained when such animals, prepared by hypophysectomy after the 45 min stimulation, had been bilaterally nephrectomized prior to stimulation. However, multiple injections of progesterone after hypophysectomy were without effect. The results are discussed in relation to variables that affect minimum requirements of LH for ovulation.

Comparative effectiveness of preoptic and tuberal stimulation for luteinizing hormone release and ovulation in two strains of rats.

Proestrous rats under pentobarbital anesthesia during the 'critical period' were electrically stimulated in either the medial preoptic area (mPOA) or the anterior basal tuber. In Osborne-Mendel (O-M) and Charles River CD rats, comparisons were made of the ovulatory responses to trains of matched biphasic pulse pairs of different microamperage, 30 sec on and 30 sec off for 45 min. In CD rats, comparisons were made of the relative efficiencies of stimulation through a coaxial platinum electrode near the midline and a pair of platinum electrodes spaced bilaterally 2 mm apart across either the mPOA or the tuber. Other comparisons, with either type of electrode in the basal tuber, were made between 4-day and 5-day cyclic CD rats with respect both to the ovulatory responses and to the serum concentrations of LH 90 min after the start of the 45-min stimulus. In both O-M and CD rats, tuberal stimulation was more effective for ovulation than mPOA stimulation. CD rats were much less responsive to mPOA stimulation (spaced electrodes) than O-M rats, but the responses of both strains to tuberal stimulation were essentially alike. In 4-day cyclic CD rats, the ovulatory responses to mPOA stimulation with the coaxial electrode were much superior to those from spaced-electrode stimulation. In contrast, tuberal stimulation with either type of electrode gave equivalent ovulation frequencies and equivalent tubal ovum numbers in both 4-day and 5-day cyclic rats. However, the serum LH concentrations disclosed somewhat better responses to stimulation with the coaxial electrode (coaxial/spaced=1.57). The advantage of stimulation with the coaxial electrode may be due to high current density or, at least in part, to its more medial location. The results are compatible with the concept of preoptic-tuberal neuronal system, diffuse rostrally and convergent upon the medial basal tuber, controlling the ovulatory surge of LH.

Intercellular communication in the rat anterior pituitary gland. An in vivo and in vitro study.

The concept of "stimulus-secretion coupling" suggested by Douglas and co-workers to explain the events related to monamine discharge by the adrenal medulla (5, 7) may be applied to other endocrine tissues, such as adrenal cortex (36), pancreatic islets (4), and magnocellular hypothalamic neurons (6), which exhibit a similar ion-dependent process of hormone elaboration. In addition, they share another feature, that of joining neighbor cells via membrane junctions (12, 26, and Fletcher, unpublished observation). Given this, and the reports that hormone secretion by the pars distalis also involves a secretagogue-induced decrease in membrane bioelectric potential accompanied by a rise in cellular [Ca++] (27, 34, 41), it was appropriate to test the possibility that cells of the anterior pituitary gland are united by junctions.

Serum prolactin and LH in early phases of delayed versus direct pseudopregnancy in the rat.

Delayed or direct pseudopregnancies were induced by electrical stimulation of the cervix at 1400 h on diestrus day 2 (D-2) or on estrus, respectively. Blood samples for measurement of prolactin and LH by radioimmunoassay were collected by rapid decapitation at 5, 15, 30, 45 or 60 min after cervical stimulation or thereafter at 3-h intervals throughout the first 6 days of leukocytic vaginal smears of pseudopregnancy (PSP L-1 to L-6). For comparison, untreated animals were decapitated at the same 3-h intervals throughout the 4-day cycle. Serum LH concentrations in all the experimental animals did not vary from those measured in the cyclic controls. Compared with the normal cycle, prolactin (PRL) levels were not different until 10 h after cervical stimulation during estrus. After stimulation on D-2, PRL secretion did not differ from that in the normal cycle until approximately 37 h later, when there was a short rise following the usual proestrus surge. In both direct and delayed pseudopregnancy, twice-daily PRL surges appeared on L-1 and, except for a missing nocturnal surge on L-2 in delayed PSP, continued regularly through L-6. The absence of any immediate increase of PRL following the D-2 stimulus strongly supports the view that information from the stimulus is retained in the central nervous system to be expressed later after a set of new, competent corpora lutea has been formed.