Gene-CYP11B2 expression in rat liver in hepatic fibrogenesis induced by CCl4

OBJECTIVE

To identify aldosterone synthase gene-CYP11B2 mRNA expression in normal and fibrotic liver in rats and evaluate the curative effect of antisterone.

METHODS

160 Wistar rats weighing about 250 g were divided into 4 groups. In the model group (n = 40), the rats were injected with 40% CCl4 (0.25 ml/100 g) subcutaneously three times a week. In the antisterone group (n = 40), the rats were injected with 40% CCl4 (0.25 ml/100 g) subcutaneously three times a week. Antisterone equivalent to 20 mg.kg-1.d-1 was given intragastrically (ig). In the malotilate group (n = 40), the rats were injected with 40% CCl4 (0.25 ml/100 g) subcutaneously three times a week. Malotilate equivalent to 50 mg/kg-1.d-1 was given ig. In the control group (n = 40), the rats were injected with olive oil only. After 2, 4, 6, 8 and 10 weeks, animals were sacrificed, and morphological examination was carried out. The area of collagen was examined with an Image Analyse System. Expression of the aldosterone synthase gene, CYP11B2 mRNA, in fibrotic and normal liver was detected by means of reverse transcriptase polymerase chain reaction (RT-PCR) and in situ hybridization.

RESULTS

In situ hybridization and RT-PCR showed that the expression of CYP11B2 mRNA, which localized in the endoplasm of hepatic stellate cells (HSCs), was up regulated when fibrogenesis occurred. Histological observation indicated that the grade of fibrosis and the area of collagen in the antisterone group were less than those in model group before 6 weeks (P < 0.05). There was no significant difference between the antisterone and malotilate groups (P > 0.05). After that, however, the grade of fibrosis and the area of collagen in the antisterone group were higher than those in the malotilate group (P < 0.05). There was no significant difference between the antisterone and model groups (P > 0.05).

CONCLUSIONS

The expression of CYP11B2 mRNA is up regulated in fibrotic liver. Antisterone can have a partial fibrogenesis-inhibiting effect in the early stages.

[Preliminary study on the methods of systematizing the data of ancient epidemic situations]

Taking the data of ancient epidemic situations in the south of the Five Ridges, as an example, the systematization materials of ancient epidemic situation guided by epidemiological methods are explored by defining the material of epidemic situation, selected compilation of relevant factors, decision of the severity, location, and its occasion etc. It is attempted to solve some problems in modernization and datalization of the collation of ancient literatures of Traditional Chinese Medicine.

Induction of IkappaBalpha mRNA expression in the brain by glucocorticoids: a negative feedback mechanism for immune-to-brain signaling

Peripheral injection of bacterial endotoxin lipopolysaccharide (LPS) induces brain mRNA expression of the proinflammatory cytokines interleukin-1beta (IL-1beta) and tumor necrosis factor-alpha and the cytokine-responsive immediate-early gene IkappaBalpha. Peripheral LPS also increases levels of plasma glucocorticoids. Whether the induction of IkappaBalpha mRNA in the brain after peripheral LPS injection is caused by the feedback action of glucocorticoids has not been determined. In this study, we examined the mRNA expression of IkappaBalpha and IL-1beta in the rat brain by in situ hybridization histochemistry. Injection of the glucocorticoid agonist dexamethasone induced IkappaBalpha mRNA expression in the brain in a pattern identical to that of LPS injection. LPS but not dexamethasone also induced IL-1beta mRNA expression. Pretreatment with dexamethasone 30 min before LPS injection enhanced the expression of IkappaBalpha mRNA in the brain in a dose-dependent manner. Immobilization of rats for 2 hr (which raises glucocorticoid levels) also induced IkappaBalpha mRNA expression without inducing the expression of IL-1beta. Brain IkappaBalpha expression induced by peripheral LPS injection was attenuated by pretreatment of rats with the glucocorticoid antagonist RU-486. Finally, increased expression of IL-1beta mRNA in the brain was observed at 4 hr after peripheral LPS injection in adrenalectomized rats compared with sham-operated rats. These results reveal that in the brain glucocorticoids selectively induce IkappaBalpha mRNA expression, which serves as a negative feedback mechanism for peripheral LPS-induced synthesis of proinflammatory cytokines. Such an inhibitory control mechanism may be important for preventing prolonged expression of proinflammatory cytokines in the brain after peripheral immune challenge.

Aldosterone overproduction and CYP11B2 mRNA overexpression in vessels of spontaneously hypertensive rats

Aldosterone is synthesized in extra-adrenal tissues such as blood vessels and brain. Damage to blood vessels could play a crucial role in perpetuating hypertension. In this study, we determined both aldosterone production and aldosterone synthase gene-CYP11B2 mRNA expression in vessels of spontaneously hypertensive rats (SHR). The results showed that aldosterone was overproduced in the vasculature of SHR, by means of ex vivo mesenteric artery perfusion, HPLC, and RIA, and that CYP11B2 mRNA expression was upregulated in aortas of SHR, confirmed by RT-PCR and Southern blot.

Suppression of cytokine production and cell adhesion molecule expression in human monocytic cell line THP-1 by Tripterygium wilfordii polysaccharide moiety

Extracts of the vine-like plant Tripterygium wilfordii (TW) have been widely used in China as an immunosuppressant and anti-inflammatory drug for the treatments of rheumatoid arthritis, lupus erythematosus and other inflammatory disorders. In this study the molecular mechanisms of action of three TW extracts (ethanol, aqueous, polysaccharide) on the expression of inflammatory cytokines and adhesion molecules were investigated by RT-PCR and immunofluorescence binding techniques. The lipopolysaccharide (LPS)-mediated stimulatory effects of tumor necrosis factor-alpha (TNF-alpha) cytokine production and cell adhesion molecule (CD11c, CD18, CD14, CD54) expression in human monocytic THP-1 cells were modulated by treatments of the TW extracts or tacrolimus (FK506). The TW polysaccharide moiety exhibited more profound immunosuppressive properties than the aqueous and ethanol extracts. Biochemical characterization of the polysaccharide moiety revealed a major molecular weight of 22 kDa (viz. PSP22). The PSP22 was found to be a potential immunosuppressant that manifests the necessary immunomodulating properties.

[Application of studies on popular words in the systematization of ancient medical books]

Based on the arrangement of Renho Temple edition of Taisu (Extremely Plain), as an example, it can be seen that by correcting the wrong popular words in ancient medical books, the causes of mistakes of ancient editions and solution for annotations of difficult terms of ancient words in the medical books are of significance.

[Toxicity of anti-herbicide gene (BAR) transgenic rice]

In order to evaluate the safety of anti-herbicide gene(BAR) transgenic rice, acute toxicity experiments, mutation experiments and a 30-day feeding test were conducted. The results were as follows: The oral LD50 for mice and rats was larger than 21.5 g/kg BW and no mutation was found. The rats consuming 16.32 and 64 g/kg BW were in good growth and development at the 30-day feeding test. The body weight, food utilization, routine blood tests, the ratio of organ weight to body weight, and patho-histological observations had no obvious change. The none effect dosage for the transgene rice was 64 g/kg.

[The effect of combined treatment of recombinant human growth hormone and insulin-like growth factor-1 on wound healing and protein catabolism in burned rats]

OBJECTIVE

To investigate the effect of combined treatment of recombinant human growth hormone (rhGH) and insulin-like growth factor-1 (IGF-1) on wound healing and protein catabolism in burned rats.

METHODS

Forty Wistar rats with deep II degree scald injury were divided randomly into four groups and received rhGH (0.1 U/kg.d), rhGH (0.1 U/kg.d) plus IGF-1 (2.0 mg/kg.d), IGF-1 (2.0 mg/kg.d) and Ringer's solution (2 ml/kg.d, as control group) respectively. The wound healing time and protein catabolism levels of every groups were compared after 2 weeks.

RESULTS

Total body weight began to increase after 2 weeks in rhGH group and rhGH plus IGF-1 group, but in control group, it was occurred after 4-5 weeks. The body weight of rhGH plus IGF-1 group was 1.65 times than that of rhGH group. The wound healing time in rhGH plus IGF-1 group (17.1 +/- 4.4) days was significantly lower than that of rhGH (20.5 +/- 4.8) days and control group (29.7 +/- 6.3) days. The protein level of rhGH plus IGF-1 group was significantly higher than that of control group and rhGH group.

CONCLUSION

It suggests that rhGH plus IGF-1 with synergism is more effective in promoting wound healing and increasing the protein catabolism.

[Research on the plague epidemic in Guangzhou (Canton) in 1894]

Early in the end of the 1870s, there were signs of local epidemic that occurred in the region of the end of Pearl River valley, most probably spread from the Beihai epidemic region through sea route. A severe epidemic of plague occurred in 1894 under the unusal dry and warm weather. However, the weather had nothing to do with the epidemic after the outbreak of the epidemic. Reports on the victims inside the city were focused in April to July, especially in May, first appeared in the regions inhabited by Muslin and Manchu centered in the whole area of western city and southern old city, where cases showed a tendency to distribute along the circular river around the city. The manifestations included swollen nodules, fever, chilliness, and coma. The death toll numbered to 0.1 million. TCM treatment includes cooling, dispersing, detoxification and blood activation, as well as acupuncture and rubbing with cold water, etc.

Effects of glycyrrhizin on production of vascular aldosterone and corticosterone

This study is to confirm the role of glycyrrhizin on blood pressure and to test the effects of glycyrrhizin on production of vascular aldosterone and corticosterone in rats. Male Wistar rats received glycyrrhizin (Sigma) 200 mg/kg/day p.o. for 5 weeks, and blood pressure was monitored by a pressure transducer. Systolic blood pressure significantly increased in Wistar rats treated with glycyrrhizin compared to that without glycyrrhizin. Mesenteric artery perfusion ex vivo and pressor responses to norepinephrine were performed. The pressor responses to norepinephrine in mesenteric arteries treated with glycyrrhizin were significantly increased. The perfusate from the mesenteric arteries was collected and applied to a Sep-Pak C 18 cartridge column, used for reverse-phase high-performance liquid chromatography, and measured for both aldosterone and corticosterone by radioimmunoassay. Levels of aldosterone were decreased but those of corticosterone increased in perfusate from arteries treated with glycyrrhizin. RT-PCR showed that glycyrrhizin inhibited the expression of 11beta- HSD2 and CYP11B2 mRNA in mesenteric arteries. These results confirm that glycyrrhizin is able to induce hypertension, and provide evidence that it inhibits the transcriptions of both 11beta-HSD2 and CYP11B2 in the vasculature, leading to lower aldosterone and higher corticosterone production in vessels, and increased vasoconstrictor responses to norepinephrine.

[An eight-factor analysis of early skeletal Class II malocclusion using Fränkel appliance]

OBJECTIVE

To investigate the change of eight-factor after Fränkel appliance treatment in skeletal class II malocclusions.

METHODS

X-ray cephalometric film.

RESULTS

Fränkel appliance can be used to enhance the growth of ramus (Factor 2) and body (Factor 1) of the mandible, decrease the angle of cranial base (Factor 8) and made the maxilla rotate (Factor 4) anteriorly, which were benefit to the treatment of class II malocclusion. However, neither the vertical (Factor 5) and sagittal (Factor 3) growth of maxilla nor the height of posterior alveolar bone (Factor 6) can be inhibited by use of Fränkel appliance.

CONCLUSION

Fränkel appliance is suitable to the treatment of class II patients with deficient mandible and almost normal maxilla, while Fränkel appliance would rather not be used for patients with overgrown maxilla or vertical growth pattern.

[The study of growth hormone on wound healing rate in adult burns]

OBJECTIVE

To determine the effects of rhGH on wound healing in adult burn patients.

METHODS

42 patients with burn wounds covering over 83% of total body surface area were enrolled in this placebo controlled prospective study. They were comparable in nutrient intake, TBSA, and full thickness burn area. For rhGH group patients rhGH subcutaneously was given in the dose of 0.2 U.kg-1 at 8 a.m. each morning for 14 days. The control group patients were given normal saline as placebo. Protein catabolism, immunocompetence, healing time of burn wounds and donor sites were assayed.

RESULTS

1. The patients in rhGH group had higher serum levels in albumin, transferrin, prealbumin and CD4 T-cells (P < 0.01). 2. The healing time of autologous skin grafting and donor site and the length of hospital stay were significantly shorter in rhGH group patients compared with control group.

CONCLUSION

rhGH could enhance the wound healing rate, improve protein anabolism and reduce the length of hospital stay in severe burn patients.

Aldosterone biosynthesis in extraadrenal tissues

OBJECTIVE

To determine whether extraadrenal tissues synthesize aldosterone in addition to vascular tissue and brain.

METHODS

Ex vivo kidney perfusion was performed in normal Wistar rats, ACEI pretreated and adrenalectomized rats prior to the perfusion experiment. After equilibration for 30 minutes, 120 ml of perfusate was collected and subjected to reverse-phase HPLC and then aldosterone was measured by RIA. By RT-PCR and Southern blot the expression of aldosterone synthase gene-CYP11B2 mRNA was studied in both kidney tissue and cultured renal tubular epithelial cell, lung and liver tissues. In situ hybridization was used to identify the cell types of liver and lung expressing CYP11B2 mRNA.

RESULTS

Production of aldosterone in the kidney perfusate was not changed in adrenalectomized rats although it was decreased in the group pretreated with ACEI perindopril. By RT-PCR and Southern blot the expression of CYP11B2 mRNA was demonstrated in both kidney tissue and cultured renal tubular epithelial cell. We have also identified CYP11B2 mRNA expression in liver and lung of rats. In situ hybridization showed that CYP11B2 mRNA was localized in the endoplasm of liver fat-storing cell (Ito cells) and type II alveolar cells of lung.

CONCLUSIONS

These studies prove that kidney, liver and lung are able to produce aldosterone.

[Effects of glycyrrhizin on blood pressure and its mechanisms]

OBJECTIVE

To confirm the action of glycyrrhizin on blood pressure by inhibiting the activity of 11beta-hydroxysteroid dehydrogenase type II (11betaHSD 2) and to test its mechanism.

METHODS

Male Wistar rats and SHRs (weighing 150 - 220 g) were given glycyrrhizin (Sigma) 200 mg/kg/day, orally for 5 weeks and 3 months. The blood pressure was monitored by means of a pressure transducer connected to a polygraph and recorded. Histological pathological changes of the nutrient arteries of the heart and aorta were studied with light microscope. Mesenteric artery perfusion ex vivo and pressor responses to norepinephrine were performed. The perfusate from the mesenteric arteries was collected and used for reverse phase high performance liquid chromatography to measure aldosterone and corticosterone level. RT-PCR was used to measure the expression of 11betaHSD 2 and aldosterone synthase (CYP11B2) mRNA.

RESULTS

The results showed that the systolic blood pressure was significantly increased in Wistar rats treated with glycyrrhizin compared with those not treated. Hyperplasia of smooth muscle cells and hypertrophy in arterioles were observed under microscope. The pressor responses to norepinephrine in mesenteric arteries treated with glycyrrhizin were significantly increased. The level of aldosterone was decreased but that of corticosterone was increased in perfusate treated with glycyrrhizin. RT-PCR showed that glycyrrhizin inhibited the expression of 11beta-HSD2and CYP11B2 mRNA in aorta.

CONCLUSION

These results confirm that glycyrrhizin is able to induce hypertension. There is evidence that it inhibits the enzymes of both 11beta-HSD2 and CYP11B2 in vasculature and leads to higher corticosterone and lower aldosterone production in vessels as well as an increase in vascular responses to norepinephrine.

The role and significance of Luo Zhiyuan's Shu yi hui bian in the history of plague in Lingnan (south of the five ridges)

Being the earliest monograph on plague in China, Luo Zhiyuan's Shu yi hui bian, not included in the National Catalogue of TCM Books, include the following contents: personal idea on the etiology of plague; Luo's friend Wu Xuanchang' unpublished Shu yu zhi fa on the treatment and manifestations of plague; Luo's specific recipe for plague based on medified Wang Qingren's Jie du huo xue decoction based on Wang Qingrens yi lin gai cuo; therapy for critical cases; many therapies applied on Lingnan, including experimental recipes, external therapy, preventive methods, and preventing recurrence methods; Luo's special administrating methods, including persisting day-and-night method, immediate persisting method, single-dose persisting method, and double-dose persisting method. He also gave several cured case records. His book, featuring unique idea with good effect, was repeatedly printed and extensively distributed, exerting influence, more or less, on the plague monographs of later ages, and occupying important position in the history of plague on Lingnan and the whole country as well. His idea of "that poisons and static blood" in pathogenesis and therapeutic principle of antitoxicity and activating blood is coincided with the results of present day clinical and laboratory studies. His administration of medicines is heuristic to the therapy of critical cases with Chinese medicaments and to the recognition of pathogenesis, etiology, and treatment of modern plague as well as other diseases of similar etiology and pathognesis and is worth of further study.

Effects of cholic acid on blood pressure and production of vascular aldosterone and corticosterone

The aims of this study were to search for the role of cholic acid in the regulation blood pressure of humans and rats and to investigate the effects of cholic acid on the production of vascular aldosterone and corticosterone in rats. Levels of serum total bile acids were measured by an enzymic spectrophotometeric method in normal controls, patients with essential hypertension, and in Wistar and spontaneously hypertensive rats. Levels in essential hypertension (7.3+/-3.4 micromol/l, n = 88) were higher than those of normal subjects (4.9+/-3.3 micromol/l, n = 86), and levels in SHR (13.9+/-3.8 micromol/l, n = 11) were slightly increased, but not significantly different from Wistar rats (10.4+/-5.1 micromol/l, n = 12). Male Wistar rats received cholic acid 80 mg/kg/day, orally, for 30 days, and blood pressure was monitored by a pressure transducer. Systolic blood pressure increased in Wistar rats treated with cholic acid compared to control rats. Mesenteric artery perfusion ex vivo was performed, and pressor responses to norepinephrine were determined in Wistar rats. The pressor responses to norepinephrine in mesenteric arteries treated with cholic acid were significantly increased. The perfusate from the mesenteric arteries was collected and applied to a Sep-Pak C 18 cartridge column for reverse phase high performance liquid chromatography, and levels of both aldosterone and corticosterone were determined by radioimmunoassay. Levels of aldosterone were decreased but those of corticosterone increased in the perfusate from arteries treated with cholic acid. Reverse transcriptase polymerase chain reaction showed that cholic acid inhibited the expression of 11beta-HSD2 and CYP11B2 mRNA in mesenteric arteries. These results reveal that cholic acid is able to induce hypertension and provide evidence that cholic acid inhibits the transcription of both 11beta-HSD2 and CYP11B2 in vasculature, leading to lower aldosterone and higher corticosterone production in vessels and increased vasoconstrictor responses to norepinephrine.

PTR3, a novel gene mediating amino acid-inducible regulation of peptide transport in Saccharomyces cerevisiae

We have isolated and characterized the Saccharomyces cerevisiae PTR3 gene by functional complementation of a mutant deficient for amino acid-inducible peptide transport. PTR3 is predicted to encode a protein of 678 amino acids that exhibits no similarity to any other protein in the database. Deletion of the PTR3 open reading frame pleiotropically reduced the sensitivity to toxic peptides and amino acid analogues. Initial rates of radiolabelled dipeptide uptake demonstrated that elimination of PTR3 resulted in the loss of amino acid-induced levels of peptide transport. PTR3 was required for amino acid-induced expression of PTR2, the gene encoding the dipeptide/tripeptide transport protein, but was not necessary for nitrogen catabolite repression of peptide import or PTR2 expression. It was determined that PTR3 also modulates expression of BAP2, the gene encoding the branched-amino acid permease. Furthermore, we present genetic evidence that suggests that PTR3 functions within a novel regulatory pathway that facilitates amino acid induction of the PTR system.

Recipient to donor conduction of atrial tachycardia following orthotopic heart transplantation

We report a case of atrial tachycardia in a 60-year-old male 8 years postorthotopic heart transplantation. At electrophysiology study, the clinical rhythm was found to arise from the remnant of the recipient atrium and was successfully terminated by delivery of radiofrequency energy. Surgical scars formed at the anastomosis of the recipient and donor atrium during the time of orthotopic heart transplantation are thought to electrically isolate the two areas. Although rarely recognized, dysrhythmias originating from the recipient atrial remnant may occur more often than previously thought.

[The treatment and rehabilitation of high-voltage electric burns]

High-voltage electric burns is refractory with high rate of amputation (46%) in early stage and unfavorable functional recovery in later stage. Little breakthrough has so far been made in this respect. From Jan. 1985 to Jan. 1996, ninety-six cases with high-voltage burns were treated in our department. Seventy-one cases of various tissue flap grafting were applied to treat early electric burns, among which sixty-four cases were successful. The amputation rate was reduced to 30%. Postoperatively, a long-term rehabilitation training at home was carried out. Most of them achieved a good appearance of the wounded sites and limbs and satisfactory ability to work or self-care. It was suggested that early thorough debridement of necrosis tissue, careful reservation of living tissue, appropriate choice of tissue flap and postoperative rehabilitation training were of great importance to achieve a good prognosis.

[Experimental research on the distribution of insulin in condyle during mandibular functional protrusion in growing rats]

The purpose of this study is to evaluate insulin change in condylar cartilage during functional advancement of rat mandible by immunohistochemical technique (ABC method) in order to provide further information about the role of insulin in orthopedics and the relationship between insulin and proliferation of condylar cartilage. Staining gradient of insulin is observed in condylar cartilage, with the stain deepest in the geriminal layer, medial in the transitional, least in the maturational layer. The posterior region of condylar cartilage in the experimental groups is shown to have thickened significantly as compared with the control groups, especially the germinal layer. Stained-positive cells exhibit deeper stain and higher percentage. The stain in the other layers is also more obvious than that in the control groups. The results suggest: Insulin level in condyle changes with the different cartilage layers. Insulin distribution appears higher when condylar chondrocytes proliferate rapidly and lower when they differentiate actively. Functional orthopedics may stimulate the growth of condylar cartilage and raise the insulin level. The demonstrates that insulin correlates with hyperplasia of conylar chondrocytes.

Correlated biochemical and radioautographic studies of protein turnover in developing rat incisor enamel following pulse-chase labeling with L-[35S]- and L-[methyl-3H]-methionine

The movement of proteins into and out of enamel was followed over time using a highly sensitive microprecipitation technique to quantify the amount of TCA-insoluble radioactivity present within small pieces of freeze-dried enamel and cells (enamel organ) dissected from the mandibular incisors of rats injected with L-[35S]-methionine. Conventional image processing techniques were also used to estimate the number of silver grains over enamel and cells in radioautographs of mandibular incisors from rats similarly injected with L-[methyl-3H]-methionine. Data from both techniques indicated that the average half-life for labeled proteins secreted into enamel was about 8.9 days. Typically, radioactive proteins accumulated in increasing amounts for 8 hours after which they were lost slowly up to 4 days and more rapidly thereafter when enamel formed during the secretory stage underwent maturation. The half-life for radioactive proteins in cells was only about 20.7 hours. No significant accumulation of radioactivity could be detected in the TCA-soluble or TCA-insoluble fractions of cells as enamel development proceeded. Results from this study suggest that radioautographs provide an accurate estimate of changes occurring to proteins in enamel and cells except at early time intervals (less than 1 hour) when a high percentage of total radioactivity is present within the TCA-soluble fraction of cells.

Benzo(a)pyrene inhibits epidermal growth factor binding and receptor autophosphorylation in human placental cell cultures

Studies investigated the effects of benzo(a)pyrene (BP) treatment on epidermal growth factor (EGF) receptor binding and kinase activity in human placental cell cultures. Specific binding of 125I-EGF to cells from early gestation placentae was significantly decreased by 37 and 60% following exposure to 1 and 10 microM BP, respectively, for 24 hr. In contrast, cells cultured from term placentae showed no inhibitory effect of either concentration of BP. Specific binding of 125I-labeled insulin and insulin-like growth factors-I and -II to early gestation cells was decreased only 15-18% at 10 microM BP, which indicates that loss of membrane receptors appears to be selective for EGF. Scatchard analysis of early gestation cells revealed that BP was associated with a dose-dependent loss in the number of high affinity EGF binding sites. Evidence from cross-linking and autophosphorylation experiments confirmed that the Mr 170,000 binding protein was decreased in a dose-dependent manner following BP treatment. In comparison, term placental cells exhibit a 26% loss of EGF receptor autophosphorylation without alteration in binding following exposure to 10 microM BP. Thus, early gestation cells exhibit a BP-related down-regulation of EGF receptors, whereas term placental cells show receptor desensitization. No adverse effect of BP treatment was observed on the incorporation of [35S] methionine into proteins secreted by early gestation cells. Further experiments compared the effects of BP with the related poly-cyclic compounds beta-naphthoflavone, alpha-naphthoflavone, and 3-methylcholanthrene. In early gestation cells, EGF binding and receptor autophosphorylation were measurably decreased at 10 microM concentrations of these polycyclic compounds, but to a lesser extent than observed with BP. In term placental cells, however, EGF binding was unchanged or increased, whereas receptor autophosphorylation was decreased 10-26%. Thus, exposure of term placental cells to these polycyclic compounds leads to a dissociation between EGF binding and receptor protein kinase activity. Finally, aryl hydrocarbon hydroxylase activity was induced 20- to 200-fold in early placental cells exposed to BP, beta-naphthoflavone, and 3-methylcholanthrene. In summary, the direct effects of BP and related compounds observed on placental EGF receptors may indicate altered function of EGF in the regulation of cell growth and differentiation in the human placenta.

A statistics-based system for treatment plant operation

This paper describes work toward development of a convenient computer system to improve everyday operation and control of the wastewater treatment process. The goal is to help the operator detect the problems in the process and to select appropriate control actions. The system comprises subsystems for a data base management, data analysis including several statistical methods, and an expert advisory system. The statistical methods investigated include construction of external reference distributions, computation of moving averages, graphical methods, discriminant functions for early detection of upsets, and several kinds of control charts. The latter two methods are still under development and are not built into the system. Reference distributions are used to help define the fuzzy terms such as high and low for the conditions of the variables involved in the expert system control rules. The system is written in dBase-III and Lotus-123 and has a user-friendly interface for the communication between the user and the system.

The effect of suboptimal concentrations of mitogens on the immunosuppressive action of azathioprine and prednisolone on human lymphocytes in vitro

The interaction of two commonly used immunosuppressive agents, azathioprine (AZA) and prednisolone sodium succinate (PSS), with three mitogens, Concanavalin A (Con A), phytohemagglutinin (PHA), and pokeweed mitogen (PWM) was studied. Using the endpoint of 50% inhibition of 3H-thymidine incorporation (ID50) as an indicator of cellular replication, the affect of suboptimal and optimal concentrations of mitogen on the immunosuppressive action of AZA or PSS on human lymphocyte replication in vitro was determined by isobolic analysis. The AZA ID50 for optimal concentrations of Con A (60 mcm/cc) was 242 +/- 21 ngm/cc (mean +/- SEM, n = 8), and at a suboptimal concentration of Con A (20 mcg/cc) it was 233 +/- 42, i.e., the AZA ID50 was independent of the concentration of Con A. This same independent interaction was found for PHA and PWM. However, at the optimal concentration of Con A (60 mcg/cc) the PSS ID50 of 523 +/- 55 ngm/cc was significantly higher (p less than 0.001) than the PSS ID at the suboptimal concentration of Con A (20 mcg/cc) which was 234 +/- 24 ngm/cc. A similar antagonistic interaction was found between PSS and either PHA or PWM. These findings emphasize the importance of accurately defining the testing parameters when assessing a drug's effect on lymphocyte proliferation. The data, along with other studies, support the hypothesis that drugs which directly interfere with DNA synthesis will not be affected by the strength of the signal for cellular replication, whereas those that modulate cellular replication are affected by the strength for lymphocyte replication.