Adsorption of polyethylene glycol (PEG) from aqueous solution onto hydrophobic zeolite

In the present study, a hydrophobic zeolite was used as an adsorbent for the adsorption of polyethylene glycol (PEG) in water solution and electroplating solution at 25 degrees C. The adsorption capacities were determined through the adsorption isotherms in a thermostated shaker. The rate of adsorption, on the other hand, was investigated in a batch adsorber under controlled process parameters such as initial PEG concentration (30, 70, 110, 150, 200, and 300 mg x dm(-3)), agitation speed (200, 800, and 1000 rpm), and adsorbent particle size (0.72, 1.44, and 2.03 mm). A batch kinetic model, according to a pseudo-second-order mechanism, has been tested to predict the rate constant of adsorption, equilibrium adsorption capacity, time of half-adsorption, and equilibrium concentration by the fitting of the experimental data. The results of the adsorption isotherm and kinetic studies show that the adsorption process can well be described with the Langmuir and Freundlich models and the pseudo-second-order equation, respectively. Comparing the values of adsorption parameters of PEG in water solution and electroplating solution, there are no significant differences. In addition, the effective diffusion coefficient of the PEG molecule in the microporous adsorbent has been estimated at about 3.20 x 10(-8) cm(2)s(-1) based on the restrictive diffusion model.

Bone morphogenetic proteins are involved in fetal kidney tissue transplantation-induced neuroprotection in stroke rats

Both bone morphogenetic proteins (BMPs) and glial cell line-derived neurotrophic factor (GDNF) reduce ischemia-induced cerebral injury in rats. Intracerebral transplantation of fetal kidney tissue, which normally expresses BMPs and GDNF during development, reduces ischemic injury in cerebral cortex. In this study, we tested the hypothesis that BMP is involved in this neuroprotective response. Fetal kidney tissue was cut into small pieces and transplanted into cortical areas adjacent to the right middle cerebral artery (MCA) in adult rats. In situ hybridization of brain indicated that these fetal kidney transplants contained high levels of BMP-7 mRNA three days after grafting. Immunohistochemical analysis of grafted brain showed co-localization of BMP-7 and PAX-2 immunoreactivity in the graft, suggesting that these transplants contained BMP protein. Some animals were grafted with fetal kidney tissue after intraventricular administration (ICV) of the BMP antagonist noggin (1 micro g) or after vehicle, followed by MCA ligation for 60 min. Animals receiving fetal kidney tissue transplantation developed significantly less body asymmetry, as compared to stroke animals that either did not receive transplantation or received fetal kidney grafts and noggin pretreatment. Analysis of these brains after triphenyltetrazolium chloride staining showed that fetal kidney tissue transplantation reduced the volume of infarction in the cerebral cortex. Noggin pretreatment reduced the protection induced by fetal kidney grafting, although noggin itself did not cause increase in cerebral infarction. Eight hours after ischemia, brain homogenates were obtained from grafted and control animals to assay caspase-3 enzymatic activity. This analysis demonstrated that fetal kidney grafts significantly reduced ischemia-induced caspase-3 activity. Reduction of caspase-3 activity could also be antagonized by noggin pretreatment. In conclusion, our data suggest that fetal kidney transplantation reduces ischemia/reperfusion-induced cortical infarction and behavioral deficits in adult rats, which are, at least partially, mediated through the effect of BMPs from the transplants.

Protective effects of glial cell line-derived neurotrophic factor in ischemic brain injury

Glial cell line-derived neurotrophic factor (GDNF), a member of the transforming growth factor-beta (TGF-beta) superfamily, has been shown to have trophic activity on dopaminergic neurons. Recent studies indicate that GDNF can protect the cerebral hemispheres from damage induced by middle cerebral arterial ligation. We found that such neuroprotective effects are mediated through specific GDNF receptor alpha-1 (GFRalpha1). Animals with a deficiency in GFRalpha-1 have less GDNF-induced neuroprotection. Ischemia also enhances nitric oxide synthase (NOS) activity, which can be attenuated by GDNF. These.data suggest that GDNF can protect against ischemic injury through a GFRalpha-1/NOS mechanism. We also found that the receptor for GDNF, GFRalpha1, and its signaling moiety c-Ret were upregulated, starting immediately after ischemia. This upregulation suggests that activation of an endogenous neuroprotective mechanism occurs so that responsiveness of GDNF can be enhanced at very early stages during ischemia.

Sex change in the protandrous black porgy, Acanthopagrus schlegeli: a review in gonadal development, estradiol, estrogen receptor, aromatase activity and gonadotropin

Black porgy, Acanthopagrus schlegeli Bleeker, a marine protandrous hermaphrodite, is functional male for the first two years of life but begins to sexually change to female after the third year. Testicular tissue and ovarian tissue was separated by connective tissue in the bisexual gonad. This sex pattern provides a very good model to study the endocrine mechanism of sex change in fish. The annual profiles of plasma estradiol, vitellogenin and 11-ketotestosterone concentrations in males were significantly different from those in the three-year-old females. Significantly high levels of plasma estradiol during the prespawning/spawning season and low levels of plasma 11-ketotestosterone during the spawning season were observed in the inversing females. No difference of plasma testosterone levels was observed in males and females. Oral administration of estradiol stimulated high levels of gonadal aromatase activity, plasma gonadotropin II levels and sex change in the two-year-old fish. Exogenous estradiol administered for 5-6 months induced a reversible sex change in one- and two-year-old fish. The sensitive period for estradiol treatment of sex change is from early prespawning to spawning season. Implantation with testosterone for more than a year could not block the natural sex change in three-year-old fish. Exogenous aromatase inhibitors (1,4,6-androstatriene-3,17-dione or fadrozole) suppressed aromatase activity in the brain. Oral administration with aromatase inhibitors for a year further inhibited the natural sex change in three-year-old black porgy and all fish became functional male with spermiation. Estrogen receptor alpha gene in the ovarian tissue of bisexual gonad is significantly less expressed than that in the vitellogenic ovary of female on the basis of reverse-transcription polymerase-chain reaction. There was no difference in the annual profiles of the plasma gonadotropin II levels in the males and natural inversing females. Plasma gonadotropin II levels were significantly higher in estradiol-treated group than those in the control. It is concluded that estradiol, aromatase activity and estrogen receptor in the ovarian tissue play an important role in the natural and controlled sex change in black porgy. The association of gonadotropin and sex change in black porgy is not clear.

Signalling of GPI-anchored CD157 via focal adhesion kinase in MCA102 fibroblasts

CD157, a glycosylphosphatidylinositol-anchored protein, has previously been shown to mediate tyrosine phosphorylation of a 130 kDa protein (p130) in several cell lines. In this study, we have identified the p130 protein to be focal adhesion kinase (FAK or pp125(FAK)). FAK undergoes phosphorylation at Tyr-397 and Tyr-861 in intact MCA102 cells stably transfected with CD157 (MCA/CD157). MCA/CD157 cells, which displayed a rounded and compact cell morphology, exhibited a dispersed distribution, in contrast to a more closely associated and elongated spindle cell shape in the vector-transfected cells. MCA/CD157 cells proliferated at a rate 20-25% slower than the control cells. Our results demonstrate, for the first time, that FAK is a downstream signalling molecule of CD157.

Utilization of agricultural waste corn cob for the preparation of carbon adsorbent

In the present study, a series of activated carbons were prepared from agricultural waste corn cob by chemical and physical activations with potassium hydroxide (KOH)/potassium carbonate (K2CO3) and carbon dioxide (CO2). The effect of process variables such as impregnation ratio, impregnation time, activation temperature and soaking time of CO2 was studied in order to relate these preparation parameters with the physical properties of final carbon products. The resulting activated carbons were characterized by nitrogen adsorption-desorption isotherms at 77 K. The surface areas and pore volumes of carbons were estimated by the BET equation, the Langmuir equation and the t-plot method. Under the experimental conditions investigated, the main parameters in the activation of corn cob were found to be the impregnation ratio and activation temperature. The soaking time of CO2 is another important variable, which had a strong effect on the pore volume development. The BET surface area and total pore volume were as large as about 2000 m2/g and about 1.0 cm3/g, respectively. This study showed that the activation of agricultural waste corn cob with KOH/K2CO3 and CO2 was suitable for the preparation of large-surface-area activated carbons.

Bone morphogenetic protein-6 reduces ischemia-induced brain damage in rats

BACKGROUND AND PURPOSE

Bone morphogenetic protein-6 (BMP6) and its receptors are expressed in adult and fetal brain. Receptors for BMP6 are upregulated in adult brain after injury, leading to the suggestion that BMP6 is involved in the physiological response to neuronal injury. The purpose of this study was to determine whether there was a neuroprotective effect of BMP6 in vivo and in vitro.

METHODS

Lactate dehydrogenase and microtubule-associated protein-2 (MAP-2) activities were used to determine the protective effect of BMP6 against H(2)O(2) in primary cortical cultures. The neuroprotective effects of BMP6 were also studied in chloral hydrate-anesthetized rats. BMP6 or vehicle was injected into right cerebral cortex before transient right middle cerebral artery (MCA) ligation. Animals were killed for triphenyl-tetrazolium chloride staining, caspase-3 immunoreactivity and enzymatic assays, and TUNEL assay. A subgroup of animals were used for locomotor behavioral assays.

RESULTS

Application of H(2)O(2) increased lactate dehydrogenase activity and decreased the density of MAP-2(+) neurons in culture. Both responses were attenuated by BMP6 pretreatment. Complementary in vivo studies showed that pretreatment with BMP6 increased motor performance and generated less cerebral infarction induced by MCA ligation/reperfusion in rats. Pretreatment with BMP6 did not alter cerebral blood flow or physiological parameters. There was decreased ischemia-induced caspase-3 immunoreactivity, caspase-3 enzymatic activity, and density of TUNEL-positive cells in ischemic cortex in BMP6-treated animals.

CONCLUSIONS

BMP6 reduces ischemia/reperfusion injury, perhaps by attenuating molecular events underlying apoptosis.

Time course study of GFRalpha-1 expression in an animal model of stroke

Previous studies have shown that intracerebral administration of glial cell line-derived neurotrophic factor (GDNF) reduces ischemia-mediated cerebral infarction. The biological effects of GDNF are mediated by GDNF-family receptor alpha-1 (GFRalpha-1) and c-Ret. In this study, we examined the levels of expression of GFRalpha-1 and c-Ret in a rat model of stroke. Adult Sprague-Dawley rats were anesthetized with chloral hydrate. The right middle cerebral artery was ligated at its distal branch for 90 min. Animals were sacrificed at 0, 6, 12, and 24 h after reperfusion and levels of expression of GFRalpha-1 and c-Ret mRNA were determined by in situ hybridization histochemistry. We found that GFRalpha-1 mRNA was up-regulated in CA3, dentate gyrus (DG), cortex, and striatum. The peak of up-regulation in DG was 6 h after reperfusion. GFRalpha-1 mRNA levels in CA3 were gradually up-regulated over the 24-h reperfusion period. In cortex, GFRalpha-1 mRNA was up-regulated at all time points; however, the peak of up-regulation was observed at 0 and 24 h after reperfusion. In striatum, an initial up-regulation of GFRalpha-1 was found at 0 h after ischemia. In striatum, up-regulation of c-Ret mRNA was detected as early as 0 h after reperfusion. A gradual increase was found at 6, 12, and 24 h after reperfusion. In conclusion, our results indicate that there are both regional and temporal differences in up-regulation of GFRalpha-1 and c-Ret after ischemia. Since GDNF is neuroprotective, up-regulation of GFRalpha-1 and c-Ret could enhance the responsiveness to GDNF and reduce neuronal damage. The selective up-regulation of GFRalpha-1 and c-Ret in different brain areas suggests that there may be regional differences in GDNF-induced neuroprotection in stroke.

Access to prenatal, delivery, and newborn care among undocumented Hispanics in the Memphis area

The purpose of this study was to examine the prenatal, delivery, and newborn care received by undocumented Hispanics in the Memphis area. The focus was to sketch a demographic profile of this population, identify barriers encountered in obtaining prenatal, delivery and newborn care, and present a five-year projection of the demand for prenatal care for this population. Participants included 97 undocumented Hispanic women, who either were pregnant or had a baby within the past 12 months, and health care providers. Most women came from Mexico (90.7%). They tended to be young, to have low educational attainment, to be homemakers, to have a high number of members in their households, to be financially supported by their spouses, and to live at or below the poverty line. The average length of time that they had been in the United States and Memphis were 42 and 21 months respectively. With regard to access to health care, undocumented Hispanics who migrated to the Memphis area lacked adequate prenatal and delivery care, and we estimated that the demand for prenatal care in this population will increase over 60% in the next five years.

Use of dexamethasone on the prophylaxis of nausea and vomiting after tympanomastoid surgery

OBJECTIVE

The aim of this study was to evaluate the prophylactic effect of dexamethasone on postoperative nausea and vomiting (PONV) in patients undergoing tympanomastoid surgery.

STUDY DESIGN

Eighty patients (n = 40 in each of two groups) undergoing tympanomastoid surgery under general anesthesia were enrolled in this randomized, double-blind, placebo-controlled study.

METHODS

After tracheal intubation, group 1 received 10 mg dexamethasone intravenously, whereas group 2 received saline intravenously. Several parameters concerning with the occurrence of PONV were evaluated.

RESULTS

We found that dexamethasone reduced the total incidence of nausea and vomiting by 45%, with a 95% confidence interval of 26% to 64% (P <.001). Furthermore, dexamethasone reduced the incidence of vomiting episodes >4 times and the incidence of patients requiring rescue antiemetics (P <.05).

CONCLUSION

Dexamethasone at a dosage of 10 mg administered intravenously is effective in preventing PONV in patients undergoing tympanomastoid surgery.

Experimental induction of chronic borreliosis in adult dogs exposed to Borrelia burgdorferi-infected ticks and treated with dexamethasone

OBJECTIVE

To develop a method to experimentally induce Borrelia burgdorferi infection in young adult dogs.

ANIMALS

22 healthy Beagles.

PROCEDURE

All dogs were verified to be free of borreliosis. Twenty 6-month-old dogs were exposed to Borrelia burgdorferi-infected adult ticks and treated with dexamethasone for 5 consecutive days. Two dogs not exposed to ticks were treated with dexamethasone and served as negative-control dogs. Clinical signs, results of microbial culture and polymerase chain reaction (PCR) testing, immunologic responses, and gross and histologic lesions were evaluated 9 months after tick exposure.

RESULTS

Predominant clinical signs were episodic pyrexia and lameness in 12 of 20 dogs. Infection with B burgdorferi was detected in microbial cultures of skin biopsy specimens and various tissues obtained during necropsy in 19 of 20 dogs and in all 20 dogs by use of a PCR assay. All 20 exposed dogs seroconverted and developed chronic nonsuppurative arthritis. Three dogs also developed mild focal meningitis, 1 dog developed mild focal encephalitis, and 18 dogs developed perineuritis or rare neuritis. Control dogs were seronegative, had negative results for microbial culture and PCR testing, and did not develop lesions.

CONCLUSIONS AND CLINICAL RELEVANCE

Use of this technique successfully induced borreliosis in young dogs. Dogs with experimentally induced borreliosis may be useful in evaluating vaccines, chemotherapeutic agents, and the pathogenesis of borreliosis-induced arthritis.

Regulation of plasma gonadotropin II secretion by sex steroids, aromatase inhibitors, and antiestrogens in the protandrous black porgy, Acanthopagrus schlegeli Bleeker

Plasma gonadotropin II (GTH II) concentrations were significantly higher (approx. 15-20-fold) in estradiol-17beta (E(2)) treated (1.0 microg or 2.5 microg g(-1) body weight) female black porgy from days 4 to 12 compared with the control. E(2) (1 microg g(-1) wt.) had a stronger stimulation on plasma GTH II in early recrudescent phase (low GSI) males (11-fold) than in high GSI and late spermiating males (2.6-fold, P< 0.05). No effect of androgens (testosterone, T; 5alpha-dihydrotestosterone, DHT) on plasma GTH II levels was observed either sex. The levels of plasma GTH II were stimulated in 1,4,6-androstatriene-3,17-dione (ATD, 1 microg g(-1), 2 microg g(-1) body wt.) and fadrozole-treated (1 microg g(-1), 3 microg g(-1) body wt.) groups compared to control. Tamoxifen (1 microg g(-1), 3 microg g(-1) body wt.) but not enclomiphene could stimulate high GTH II levels in plasma. In another experiment of ATD in combination with T, T treatment further attenuated the ATD stimulation of plasma GTH II levels. We concluded that GTH II secretion is positively regulated by an estrogen-specific effect in female and male black porgy. Gonadal stage had significant effects on the responsiveness of GTH II to E(2) stimulation in males. A negative aromatase-dependent feedback control of plasma GTH II levels was also suggested in the protandrous black porgy, Acanthopagrus schlegeli.

Preparation of activated carbons from corn cob catalyzed by potassium salts and subsequent gasification with CO2

In the present study, granular activated carbons were prepared from agricultural waste corn cob by chemical activation with potassium salts and/or physical activation with CO2. Under the experimental conditions investigated, potassium hydroxide (KOH) and potassium carbonate (K2CO3) were effective activating agents for chemical activation during a ramping period of 10 degrees C/min and subsequent gasification (i.e., physical activation) at a soaking period of 800 degrees C. Large BET surface areas (>1,600 m2/g) of activated carbons were thus obtained by the combined activation. In addition, this study clearly showed that the porosity created in the acid-unwashed carbon products is substantially lower than that of acid-washed carbon products due to potassium salts left in the pore structure.

A critical review of the arguments for insurance coverage for smoking-cessation therapies

This article elucidates the reasons most insurance companies do not cover smoking-cessation therapies despite their obvious benefits. It critically reviews the arguments for and against using a universal mandate as a strategy to increase use of smoking-cessation programs to realize the associated health benefits and cost-savings. While convincing arguments exist to mandate insurance coverage for self-destructive health behaviors, their merit is tempered by several valid counter arguments. For example, insurance coverage for small, routine, and predictable events, such as smoking-cessation treatment, violates the "first principles" of what ought to be covered when considered from the traditional insurance perspective. An insurance solution to risky behaviors may be to make undesirable behaviors more undesirable to individuals by raising premiums rather than to make them less undesirable with subsidies.

The association of smoking and the cost of military training

OBJECTIVE

To determine if premature discharge from the US Air Force was associated with the smoking status of recruits.

DESIGN AND SETTING

A total of 29 044 US Air Force personnel recruited from August 1995 to August 1996 were administered baseline behavioural risk assessment surveys during basic military training. They were tracked over a 12 month period to determine those who were prematurely discharged.

MAIN OUTCOME MEASURES

Excess training costs as a result of premature discharge.

RESULTS

In this 12 month period, 14.0% of those entering the US Air Force were discharged at a one year follow up. In both univariate and multivariate models, the best single predictor of early discharge was smoking status. Overall, 11.8% of non-smokers versus 19.4% of smokers were prematurely discharged (relative risk 1.795).

CONCLUSIONS

Using US Department of Defense data on the cost of military training, recruits who smoke in the US Air Force are associated with $18 million per year in excess training costs. Applied to all service branches, smoking status, which represents a constellation of underlying behaviours and attitudes that can contribute to early discharge, is associated with over $130 million per year in excess training costs.

Hepatocellular carcinoma with Pancoast's syndrome as an initial symptom: a case report

Pancoast's syndrome refers to a condition consisting of Horner's syndrome and arm pain that is most commonly found in patients with a lung tumor of the superior sulcus invading the upper ribs or spine, lower brachial plexus and sympathetic chain. We report a 76-year-old female who had a thoracic inlet mass that presented as Pancoast's syndrome, showing profound pain, numbness and weakness of the left upper limb. Further evaluation revealed an increased level of serum alpha-fetoprotein (24278 ng/ml), cryptogenic liver cirrhosis and primary hepatocellular carcinoma with protruding T3 vertebra metastasis that resulted in Pancoast's syndrome. To our knowledge, it is a rare case and only one case has been reported previously.

Methamphetamine potentiates ischemia/reperfusion insults after transient middle cerebral artery ligation

BACKGROUND AND PURPOSE

Previous studies have indicated that both methamphetamine (MA) and ischemia/reperfusion injuries involve reactive oxygen species formation and activation of apoptotic mechanism. That MA could have a synergistic or additive effect with stroke-induced brain damage is possible. The purpose of the present study was to investigate whether administration of MA in vivo would potentiate ischemic brain injury.

METHODS

Adult CD-1 mice were pretreated with MA or saline. Each animal later was anesthetized with chloral hydrate and placed in a stereotaxic frame. A subset of animals received intracerebral administration of glial cell line-derived neurotrophic factor (GDNF). The right middle cerebral artery and bilateral carotids were transiently occluded for 45 minutes. Regional cerebral blood flow was measured by laser Doppler. Animals were sacrificed for triphenyltetrazolium chloride staining and p53 mRNA Northern blot assay after 24 hours of reperfusion. Cortical and striatal GDNF levels were assayed by ELISA.

RESULTS

We found that pretreatment with MA increased ischemia-induced cerebral infarction. Ischemia or MA alone enhanced p53 mRNA expression. Moreover, MA potentiated expression of p53 mRNA in the ischemic mouse brain. MA pretreatment decreased GDNF levels in ischemic striatum. Intracerebral administration of GDNF before ischemia reduced MA-facilitated infarction.

CONCLUSIONS

Our data indicate that MA exacerbates ischemic insults in brain, perhaps through the inhibition of GDNF-mediated pathways and suggest that MA may antagonize endogenous neuroprotective pathways as part of its mechanism of action.

Estradiol-17beta stimulates gonadotropin II expression and release in the protandrous male black porgy Acanthopagrus schlegeli Bleeker: a possible role in sex change

The objective of the present study was to investigate the in vivo effects of sex steroids (estradiol-17beta, E(2); testosterone, T) and the nonaromatizable androgen 5alpha-dihydrotestosterone (DHT) on the levels of gonadotropin II (GTH II) in plasma and pituitary and on aromatase activity in 2-year-old male black porgy, Acanthopagrus schlegeli, during the prereproductive season. Black porgy GTH II and GTH II beta subunits were purified and anti-GTH II beta serum was induced. A specific radioimmunoassay for black porgy GTH II was developed. cDNA GTH II beta was also cloned from a black porgy pituitary cDNA library for use as a probe for Northern analysis. Male fish were divided into eight groups (n = 64): control; E(2) (3 doses, 2.4 ng, 72 ng, and 2.2 microg/g body weight); T (2 doses, 72 ng and 2.2 microg/g body weight); and DHT (2 doses, 72 ng and 2.2 microg/g body weight). Fish were injected with the respective vehicle or different doses of material on days 0, 8, and 16. Plasma was collected at 4-day intervals from days 4 to 20. Plasma GTH II concentrations were significantly increased (up to 45-fold) in the E(2) group from days 4 to 20 in a dose-dependent manner. In a further experiment during the late reproductive season, plasma GTH II levels increased at 4 h and on days 1 and 2 following a single injection of 1.0 microg E(2)/g body weight (on day 0). Androgens (T or DHT) had little or no effect on plasma GTH II. Pituitary GTH II contents on day 20 were significantly lower in the 72-ng E(2) and 2.2-microg E(2) groups but not in the 2.4-ng E(2) group compared with the control group. Pituitary GTH II beta mRNA levels were significantly stimulated in the 72-ng and 2.2-microg E(2) groups on day 20. Gonadal aromatase activity was not significantly changed in any of the treated or control groups. It is concluded that GTH II secretion in black porgy is regulated by an estrogen-specific effect. Increased plasma GTH II levels or other factors in addition to E(2) might be involved in the regulation of gonadal aromatase activity and sex change in protandrous black porgy.

Differential in vitro suppressive effects of steroids on leukocyte phagocytosis in two teleosts, tilapia and common carp

The objectives of this study were to investigate the potential roles of cortisol and gonadal steroids in the phagocytic activity of peripheral blood leukocytes in two teleosts, tilapia (Oreochromis niloticus x O. aureus) and common carp (Cyprinus carpio). An in vitro microtiter plate assay, measuring incorporation of FITC-latex beads into peripheral blood leukocytes, was developed for the first time in teleosts. Peripheral blood leukocytes were cultured in AL medium with tested compounds in a microfluor black plate at 25 degrees C. FITC-latex beads were further incubated for phagocytosis and engulfed fluorescent intensity in phagocytes was detected fluorometrically. Cortisol suppressed leukocyte phagocytosis in a dose (10(-14) to 10(-4) M)- and time (0.5 to 8 h)-dependent manner in tilapia. The glucocorticoid agonist dexamethasone had a suppressive effect similar to that of cortisol, while cortisone and the mineralocorticoid aldosterone had only a weak effect in tilapia. High doses of estradiol and ethynylestradiol, but not of estrone, suppressed phagocytosis in tilapia. No suppressive effect on phagocytosis was observed with various concentrations of progesterone, testosterone, and 11-ketotestosterone. Triiodothyronine was also inactive on phagocytosis. A combination of estradiol and cortisol potentiatingly suppressed phagocytosis. Actinomycin D and cycloheximide blocked the suppressive effects of cortisol and estradiol. Cortisol had weaker suppressive effects on the phagocytosis of leukocytes in common carp than tilapia. Other steroids had no suppressive action on phagocytosis in common carp. It is concluded that the suppressive effects of cortisol and estradiol on phagocytosis in tilapia are mediated by specific glucocorticoid receptors and estrogen receptors, respectively. Cortisol would play a main and important role on the down-regulation of phagocytic activity. Sexual steroids, such as estradiol, also could interact with cortisol to further suppress immunity in tilapia. Differential responsiveness of the immune system to suppressive effects of steroids, among teleosts species, has been demonstrated.

Adsorption Equilibrium of Polyethylene Glycol in the Copper Electroplating Solution on Activated Carbon

Polyethylene glycol (PEG) used as a brightening and stabilization agent at the concentration of 30 mg dm(-3) is a major organic additive in the copper electroplating solution. Activated carbon, Calgon Filtrasob 400, is used as the adsorbent to remove the PEG from the used electroplating solution in order to broaden the appeal of recycling it. The equilibrium of adsorption is attained within 14 days. The effect of the temperature on the amount of PEG adsorbed on the activated carbon is insignificant for the temperatures ranged from 288 to 313 K. The adsorption isotherm of PEG conforms to the Langmuir isotherm, q(e)=Q(L)K(L)C(e)/(1+K(L)C(e)), with a high correlation coefficient of 0.9979. The large values of the monolayer adsorption capacity, Q(L), of 303 mg g(-1) and the equilibrium constant, K(L), of 0.273 dm(3) mg(-1) show a great adsorption potential of PEG on the activated carbon. A high removal efficiency would be expected at such a low original concentration of PEG. From the results mentioned above, it is feasible to use activated carbon for removing PEG from the electroplating solution, thereby achieving the appeal of recycling. Copyright 2000 Academic Press.

Effects of Burn-off and Activation Temperature on Preparation of Activated Carbon from Corn Cob Agrowaste by CO(2) and Steam

Previous studies have successfully demonstrated that corn cob is a suitable precursor for production of good activated carbon by chemical activation. However, respond to the need for cleaner production, this study focuses on the physical activation by gasifying agents such as CO(2) and steam. The activation temperatures under investigation are 1073 and 1173 K. Within the limit of 50 wt% burn-off, experimental results reveal that the BET surface area, pore volume, and average pore diameter of the resulting activated carbon generally increase with the extent of burn-off in both gasifying agents and at both temperatures. The higher activation temperature can overcome the drawbacks of a longer period of activation required to attain larger surface area and can offer higher potential to produce activated carbon of greater adsorption capacity from agriculture wastes such as corn cobs. Additionally, the BET surface areas of properly prepared activated carbons can satisfy commercial requirements, when compared with commercial activated carbon. The BET surface areas of the activated carbons after about 71 and 59 wt% burn-off of CO(2) and steam activations at 1173 K are 1705 and 1315 m(2)/g, respectively, indicating high adsorption capacities. Thus, it is feasible to produce high-quality microporous activated carbon from corn cob agrowaste using N(2) carbonization followed by physical activation with CO(2) or steam. Copyright 2000 Academic Press.

Hyperbaric oxygen therapy for treatment of postischemic stroke in adult rats

The efficacy of hyperbaric oxygen (HBO) therapy for treatment of stroke remains to be validated in the laboratory. We report here that adult rats subjected to occlusion of the middle cerebral artery and subsequently exposed to HBO (3 atm, 2 x 90 min at a 24-h intervals; animals terminated shortly after the second treatment) or hyperbaric pressure (HBP; 3 atm, 2 x 90 min at a 24-h interval; animals terminated shortly after the second treatment) immediately after the ischemia or after a 60-min delay generally displayed recovery from motor deficits at 2.5 and 24 h of reperfusion, as well as a reduction in cerebral infarction at 24 h of reperfusion compared to ischemic animals subjected to normal atmospheric pressure. While both HBO and HBP treatments promoted beneficial effects, HBO produced more consistent protection than HBP. Treatment with HBO immediately or 60 min after reperfusion equally produced significant attenuations of cerebral infarction and motor deficits. In contrast, protective effects of HBP treatment against ischemia were noted only when administered immediately after ischemia, which resulted in a significantly reduced infarction volume, but only produced a trend toward decreased behavioral deficits. The present results demonstrate that HBO and, to some extent, HBP reduced ischemic brain damage and behavioral dysfunctions.