Investigation of an artificial intelligence technology—Model trees

This study has investigated an artificial intelligence technology - model trees - as a modelling tool applied to an immediate release tablet formulation database. The modelling performance was compared with artificial neural networks that have been well established and widely applied in the pharmaceutical product formulation fields. The predictability of generated models was validated on unseen data and judged by correlation coefficient R(2). Output from the model tree analyses produced multivariate linear equations which predicted tablet tensile strength, disintegration time, and drug dissolution profiles of similar quality to neural network models. However, additional and valuable knowledge hidden in the formulation database was extracted from these equations. It is concluded that, as a transparent technology, model trees are useful tools to formulators.

Comparison of neurofuzzy logic and decision trees in discovering knowledge from experimental data of an immediate release tablet formulation

Understanding of the cause-effect relationships between formulation ingredients, process conditions and product properties is essential for developing a quality product. However, the formulation knowledge is often hidden in experimental data and not easily interpretable. This study compares neurofuzzy logic and decision tree approaches in discovering hidden knowledge from an immediate release tablet formulation database relating formulation ingredients (silica aerogel, magnesium stearate, microcrystalline cellulose and sodium carboxymethylcellulose) and process variables (dwell time and compression force) to tablet properties (tensile strength, disintegration time, friability, capping and drug dissolution at various time intervals). Both approaches successfully generated useful knowledge in the form of either "if then" rules or decision trees. Although different strategies are employed by the two approaches in generating rules/trees, similar knowledge was discovered in most cases. However, as decision trees are not able to deal with continuous dependent variables, data discretisation procedures are generally required.

Role of tissue transglutaminase type 2 in calbindin-D28k interaction with ataxin-1

Spinocerebellar ataxia-1 (SCA1) is caused by the expansion of a polyglutamine repeats within the disease protein, ataxin-1. The mutant ataxin-1 precipitates as large intranuclear aggregates in the affected neurons. These aggregates may protect neurons from mutant protein and/or trigger neuronal degeneration by encouraging recruitment of other essential proteins. Our previous studies have shown that calcium binding protein calbindin-D28k (CaB) associated with SCAl pathogenesis is recruited to ataxin-l aggregates in Purkinje cells of SCAl mice. Since our recent findings suggest that tissue transglutaminase 2 (TG2) may be involved in crosslinking and aggregation of ataxin-l, the present study was initiated to determine if TG2 has any role in CaB-ataxin-l interaction. The guinea pig TG2 covalently crosslinked purified rat brain CaB. Time dependent progressive increase in aggregation produced large multimers, which stayed on top of the gel. CaB interaction with ataxin-l was studied using HeLa cell lysates expressing GFP and GFP tagged ataxin-l with normal and expanded polyglutamine repeats (Q2, Q30 and Q82). The reaction products were analyzed by Western blots using anti-polyglutamine, CaB or GFP antibodies. CaB interacted with ataxin-1 independent of TG2 as the protein-protein crosslinker DSS stabilized CaB-ataxin-l complex. TG2 crosslinked CaB preferentially with Q82 ataxin-1. The crosslinking was inhibited with EGTA or TG2 inhibitor cystamine. The present data indicate that CaB may be a TG2 substrate. In addition, aggregates of mutant ataxin-l may recruit CaB via TG2 mediated covalent crosslinking, further supporting the argument that ataxin-l aggregates may be toxic to neurons.

Tissue transglutaminase crosslinks ataxin-1: possible role in SCA1 pathogenesis

Transglutaminase type 2 (TG2) has recently been implicated in crosslinking of mutant huntingtin protein into aggregates. Here we show that TG2 also crosslinks spinocerebellar ataxia-1 (SCA1) gene product ataxin-1. HeLa cell lysates expressing GFP tagged ataxin-1 with 2, 30 or 82 glutamines showed covalent crosslinking of ataxin-1 when incubated with exogenously added TG2. This crosslinking was inhibited by TG2 inhibitor cystamine. SCA1 transgenic mice which overexpress the mutant ataxin-1 in cerebellar Purkinje cells showed elevated nuclear TG2 in the absence of ataxin-1 nuclear aggregates. The addition of purified TG2 to the nuclear extracts or addition of SCA1 nuclear TG2 to GFP-Q82 HeLa cell lysates resulted in the formation of insoluble aggregates. These data indicate that ataxin-1 is a substrate of TG2. Further, in SCA1 TG2 may translocate to the nucleus in response to nuclear accumulation of mutant ataxin-1 at early stages of the disease.

Stereoselectivity and interaction between the glucuronidation of S-(-)- and R-(+)-propranolol in rat hepatic microsomes pretreated with different inducers

Phase II glucuronidation metabolism of side-chain propranolol was studied using microsomes from rats treated with the inducers beta-naphthoflavone (BNF) or dexamethasone (Dex). The glucuronide concentrations of propranolol enantiomers were assayed by RP-HPLC. The kinetic constants of glucuronidation, Km, Vmax and Clint were determined. There are significant differences between the R- and S-enantiomeric glucuronide in Km, Vmax and Clint P < 0.05, P < 0.01 and P < 0.05 in control microsome. There are significant differences in Km and Clint (P < 0.01 or P < 0.001) but no significant differences in Vmax (P > 0.05) between R and S-enantiomeric glucuronide in the microsomes induced with Dex and BNF. The formation of S-(-)-propranolol glucuronide was inhibited by R-(+)-propranolol from the rat microsomes pretreated with BNF and Dex. The glucuronidation metabolism of propranolol enantiomers exhibited the stereoselectivity in rat hepatic microsomes induced with BNF or Dex. Multiple UGT1A and 2B may be involved in stereoselective O-glucuronidation of propranolol enantiomers in rat liver microsomes. The glucuronides produced were in favor of the R-enantiomer. There is an interaction between the glucuronidation of R- and S-enantiomer.

Attenuation of changes in G(i)-proteins and adenylyl cyclase in heart failure by an ACE inhibitor, imidapril

Cardiac dysfunction in animals with congestive heart failure due to myocardial infarction (MI) is known to be associated with a wide variety of defects in receptor and post-receptor mechanisms. Since the heart function have been shown to be improved by treatment with different angiotensin converting enzyme (ACE) inhibitors, we examined the effects of imidapril, an ACE inhibitor, on changes in post-receptor mechanisms involving adenylyl cyclase (AC) and G proteins in the failing heart. Heart failure in rats was induced by occluding the coronary artery and 3 weeks later the animals were treated daily with 1 mg/kg (orally) imidapril for 5 weeks. The animals were assessed for their left ventricular function and crude membranes were isolated from the viable left ventricle and examined for AC activities as well as G-protein activities and expression. Animals with heart failure exhibited depressions in ventricular function and AC activities in the absence or presence of forskolin, NaF and Gpp(NH)p. The AC activity in the presence of pertussis toxin was increased whereas that in the presence of cholera toxin was decreased in the failing heart. Protein contents and mRNA levels for G(i)-proteins were increased whereas those for G(s)-proteins were unaltered in the infarcted heart. All these changes due to MI were prevented by imidapril treatment. The results indicate that the depressed cardiac function in the failing heart may partly be due to the direct effects of changes in AC and G(i) proteins.

Statistical visualization for data exploration: a case study on Sydney Olympic Park

Due to the powerful graphic interface in modern computers, visualization techniques have become more and more popular for data exploration. As a preliminary investigation, visualization is a greatly useful tool to lead to further statistical analysis and modelling. It is likely that historical environmental data from a range of different studies may contain useful information that should be assessed for determining management actions. However, these historical data are collected from many different studies, which have different space and/or time scales making the visualization process complicated. In this paper we present several ways of visualizing historical data based on a study at Sydney Olympic Park. The tools include spatial coverage and variation for different spatial resolutions, temporal coverage and time series plots for different time scales, multi-panel scatterplots for a small number of variables and "one-to-all" scatterplots for a large number of variables.

Aggregated DsRed-tagged Cx43 and over-expressed Cx43 are targeted to lysosomes in human breast cancer cells

To investigate if either wild-type or aggregated Cx43 is abnormally targeted to lysosomes in human breast tumor cells, we examined the fate of DsRed-tagged Cx43 and over-expressed Cx43 in communication-deficient HBL-100 and MDA-MB-231 cells. DsRed-tagged Cx43 was assembled into gap junctions in control normal rat kidney cells that express endogenous Cx43 but not in Cx43-negative HBL-100 cells. However, when HBL-100 cells were engineered to coexpress wild-type Cx43 a population of DsRed-tagged Cx43 was rescued and assembled into gap junctions. Co-expression of wild-type Cx26 failed to rescue the assembly of DsRed-tagged Cx43 into gap junctions. Immunolocalization studies revealed that DsRed-tagged Cx43 was aggregated and partially localized to lysosomes. Interestingly, when human MDA-MB-231 breast tumor cells over-expressed wild-type Cx43, Cx43 protein primarily localized to lysosomes. Together, these studies provide evidence for Cx43 being targeted to lysosomes as a result of misfolding and aggregation, while in other cases, the delivery of wild-type Cx43 to lysosomes appears to be due to defects innate to the breast tumor cell type.

[Study on anticancer activity of Syngnathus in vitro]

OBJECTIVE

To study the anticancer activity of Syngnathus in vitro.

METHOD

Observing the influence of different extracts from Syngnathus on growth of different cancer cell strains by MTT method.

RESULT

It has been found out that the fat-soluble nonsaponified extract from Temminck et Schlegel and the alcoholic extract from Syngnathus acus have cytotoxic activities. The nonsaponified extract from Temminck et Schlegel can inhibit the growth of cancer cell strains KB, Hela, PAA, K562, and Bcap37, and the alcoholic extract from Syngnathus acus can inhibit the growth of cancer cell strin KB, But Bloch shows no apparent anticancer activity.

CONCLUSION

Syngnathus has promising prospects as an anticancer Chinese medicine.

Comparative analysis and application of fluorescent protein-tagged connexins

In order to examine connexin transport, assembly, and turnover in living cells, we tagged green fluorescent protein or its color variants to several members of the connexin family of proteins. When green fluorescent protein was tagged to the carboxyl terminal end of connexin43 (Cx43-GFP), the resulting fusion protein was transported and assembled into functional gap junctions. However, when GFP was tagged to the amino terminal end of Cx43 (GFP-Cx43), this chimera was biosynthesized, transported to the plasma membrane, but failed to form gap junction channels that could transfer Lucifer yellow. Single cells that expressed Cx43-GFP were capable of transporting this fusion protein to the cell surface in the absence of cell-cell contact. Imaging of Cx43-yellow (Y)FP (Cx43-YFP) was quite efficient; however, the low quantum yield Cx43-BFP and the requirement for ultraviolet excitation made this chimera less suitable for time-lapse imaging. Cx43-cyan C(FP) (Cx43-CFP) was more suitable for imaging than Cx43-blue (B)FP and could be effectively separated from Cx43-YFP. The versatility of tagging GFP to the carboxyl terminal end of other members of the connexin family was established when Cx32-GFP and Cx26-YFP were found to assemble into gap junctions capable of transferring Lucifer yellow. Finally, we are examining the effectiveness of using a new red fluorescent protein (DsRed) fused to connexins in combination with Cx-GFP to simultaneously examine the kinetics, transport and turnover of two connexins. Together, our studies suggest that tagging fluorescent proteins to the carboxyl terminal end of connexins is an effective and valuable approach for studying the life cycle and dynamics of connexins in living cells.

[Influence of free radical inducer on the level of oxidative stress in brain of rats with fluorosis]

OBJECTIVE

To study changes in content of lipid peroxide and composition of fatty acids in the brain of rats affiliated with chronic fluorosis after treatment with free radical inducer (ferric ion).

METHODS

Thirty-six Wistar rats were divided into three groups, fed with similar fodder and varied concentrations of fluoride in drinking water, and were killed five months after treatment. Lipid peroxidation was induced by ferric ions. Malondialdehyde content in brain was analysed by high-performance liquid chromatography; oxygen consumption was determined with an oxygen electrode and fatty acid composition was measured by gas chromatography in brain tissues of the rats.

RESULTS

In the brain tissues, content of malondialdehyde and oxygen consumption increased, composition of polyunsaturated fatty acids decreased and that of saturated fatty acids decreased after treatment with free radical inducer in the treated group, as compared with those in control group.

CONCLUSION

Over uptake of fluoride for a long term could cause potential increase in the level of oxidative stress in the brain tissue.

Immunolocalization of 5alpha-reductase isozymes in acne lesions and normal skin

BACKGROUND

Dihydrotestosterone mediates androgen-dependent diseases, such as acne, hirsutism, and androgenetic alopecia. This hormone is produced from testosterone by the 5alpha-reductase enzyme. There are 2 isozymes of 5alpha-reductase (types 1 and 2) that differ in their localization within the body and even within the skin. Activity of the type 1 isozyme predominates in sebaceous glands, where it may be involved in regulation of sebum production. Since specific inhibition of 5alpha-reductase type 1 may represent a novel therapeutic approach to acne, it is important to define the localization of these isozymes in normal sebaceous follicles and acne lesions.

OBSERVATIONS

Skin biopsy specimens were obtained from the backs of 11 subjects: 8 with acne and 3 without acne. Sections of normal follicles, open comedones, closed comedones, and inflammatory lesions were incubated with antibodies to types 1 and 2 5alpha-reductase. In all samples, the type 1 antibody localized specifically to sebaceous glands, and the type 2 antibody localized to the companion layer of the hair follicle (the innermost layer of the outer root sheath) and granular layer of the epidermis. Localization of the type 2 isozyme was also noted within the walls of open and closed comedones and in endothelial cells from sections of inflammatory lesions.

CONCLUSIONS

The immunolocalization of 5alpha-reductase isozymes in normal sebaceous follicles and acne follicles is similar to the pattern described in terminal hair follicles and corresponds with the findings of biochemical studies that have demonstrated predominance of type 1 activity in sebaceous glands. The function of type 2 5alpha-reductase in comedones or endothelial cells in inflammatory lesions is unknown.

[A preliminary study of PSA level in 646 healthy men in Beijing]

OBJECTIVE

To evaluate the levels of total PSA (tPSA), free PSA (fPSA) and fPSA/t PSA ratio in healthy men in Beijing and analyze the relationship between age and PSA indexes.

METHODS

Serum tPSA and fPSA were measured by electrochemi luminescence immune assay (ECLIA) and fPSA/t PSA ratio was calculated in 646 healthy men of 20 approximately 90 years old. The relationship between age and PSA indexes was analyzed by simple linear regression.

RESULTS

In 20 approximately 30 years old cases, t PSA was 0.9 ng/ml +/- 0.6 ng/ml, fPSA was 0.27 ng/ml +/- 0.19 ng/ml and fPSA/t PSA ratio was 0.36 +/- 0.20. In 31 approximately 40 years old group, tPSA was 0.8 ng/ml +/- 0.6 ng/ml, fPSA was 0.22 ng/ml +/- 0.15 ng/ml and fPSA/tPSA ratio was 0.34 +/- 0.25. In 41 approximately 50 years old group, tPSA was 0.8 ng/ml +/- 0.6 ng/ml, fPSA was 0.21 ng/ml +/- 0. 14 ng/ml and fPSA/tPSA ratio was 0.34 +/- 0.23. In 51 approximately 60 years old group, tPSA was 1.0 ng/ml +/- 0.6 ng/ml, fPSA was 0.25 ng/ml +/- 0.15 ng/ml and fPSA/tPSA ratio was 0.31 +/- 0.19. In 61 approximately 70 years old group, tPSA was 1.0 ng/ml +/- 0. 7 ng/ml, fPSA was 0.25 ng/ml +/- 0.18 ng/ml and fPSA/tPSA ratio was 0.27 +/- 0.18. In 71 approximately 80 years old group, tPSA was 1.1 ng/ml +/- 0.7 ng/ml, fPSA was 0.31 ng/ml +/- 0.23 ng/ml and fPSA/tPSA ratio was 0.29 +/- 0.14. In 81 approximately 90 years old group, tPSA was 1.3 ng/ml +/- 1.1 ng/ml, fPSA was 0.4 ng/ml +/- 0.4 ng/ml and fPSA/tPSA ratio was 0.36 +/- 0.17. By univariate analysis, no correlation was found between serum PSA indexes and ages.

CONCLUSIONS

The reference ranges of all PSA indexes in Chinese men may be lower than in that western men. There is no correlation between serum PSA indexes and ages. The reference range of 0 to 4 ng/ml used in the West may not be applicable to Chinese patients.

[Hygienic appraisal on apartment houses in the western district of Beijing]

A survey on the essential factors of building hygiene of 12 apartment houses in the Western District of Beijing was presented. The site environment layout of rooms, illumination, ventilation, microclimate, indoor air quality, floor area per person, necessary equipped facilities etc, in the apartment, and its hygienic appraisal were assessed. The results and appraisal of the study showed that almost all the essential factors of building hygiene complied with the requirements of the national hygienic standards for air pollutants in indoors and in hotels. On the other hand, there existed some shortcomings, such as the gas appliance for heating water produced large amount of pollutants in the kitchen it there was no proper ventilation for it. Suggestions for their improvements were put forward. The appraisal is useful for improving the living conditions in apartment houses and also useful for the design and construction.

Captopril treatment improves the sarcoplasmic reticular Ca(2+) transport in heart failure due to myocardial infarction

Although captopril, an angiotensin-converting enzyme (ACE) inhibitor, has been shown to exert a beneficial effect on cardiac function in heart failure, its effect on the status of sarcoplasmic reticulum (SR) Ca(2+) transport in the failing heart has not been examined previously. In order to determine whether captopril has a protective action on cardiac function, as well as cardiac SR Ca(2+)-pump activity and gene expression, a rat model of heart failure due to myocardial infarction was employed in this study. Sham operated and infarcted rats were given captopril (2 g/l) in drinking water; this treatment was started at either 3 or 21 days and was carried out until 8 weeks after the surgery. The untreated animals with myocardial infarction showed increased heart weight and elevated left ventricular end diastolic pressure, reduced rates of pressure development and pressure fall, as well as depressed SR Ca(2+) uptake and Ca(2+)-stimulated ATPase activities in comparison with the sham control group. These hemodynamic and biochemical changes in the failing hearts were prevented by treatment of the infarcted animals with captopril. Likewise, the observed reductions in the SR Ca(2+) pump and phospholamban protein contents, as well as in the mRNA levels for SR Ca(2+) pump ATPase and phospholamban, in the failing heart were attenuated by captopril treatment. These results suggest that heart failure is associated with a defect in the SR Ca(2+) handling and a depression in the gene expression of SR proteins; the beneficial effect of captopril in heart failure may be due to its ability to prevent remodeling of the cardiac SR membrane.

[Study on proteins of allele by using the microisoelectric focusing]

Clear protein electrophoresis pattern of single pollen grain from Cucurbita pepo L. was obtained with isoelectric focusing and supersensitive stain technique. The results showed that there were two special distributing protein bands near acidity pole. In species I, the two protein bands were a little near to acidity pole and in species II, that was a little far from acidity pole. In species III, the two protein bands distributed either like species I or like species II and the distributed ratio was 1:1. Moreover, we discuss how to identify relative purity of gene with the sorts of the special proteins.

Serotonin receptor subtypes that depolarize guinea pig inferior mesenteric ganglion neurons

Our previous studies indicated that serotonin (5-HT) depolarized a majority of guinea pig inferior mesenteric ganglion (IMG) neurons and may be another transmitter for the noncholinergic late slow excitatory postsynaptic potential (ls-EPSP) in the IMG. However, the subtypes of 5-HT receptor mediating these responses have not yet been identified. Using intracellular recording, we examined the effect of 5-HT receptor antagonists with specificity to various 5-HT receptor subtypes on the 5-HT-mediated depolarization and ls-EPSP in IMG neurons in vitro. Cyproheptadine, a 5-HT(1/2) receptor antagonist, reversibly inhibited the slow, but not the fast, depolarization and ls-EPSP in the 5-HT-sensitive neurons. Both mianserin and spiperone, 5-HT(2) and 5-HT(1A) receptor antagonists, did not significantly alter either the fast or slow depolarizing responses or the ls-EPSP. The 5-HT(3) receptor antagonist MDL 72222 (Bemesetron) completely inhibited the fast depolarization with little diminution of the slow depolarization and ls-EPSP. Superfusion of putative 5-HT(1P) receptor antagonist, BRL 24924 (Renzapride), reversibly attenuated both the depolarization and ls-EPSP. However, 5-HT-insensitive neurons with ls-EPSP were found to be insensitive to both cyproheptadine and BRL 24924. In most 5-HT-sensitive neurons, the 5-HT(3) receptor agonist, 2-methyl-5-HT, and the selective 5-HT(1P) agonist, MCPP or 5-OHIP, evoked a fast and a slow depolarization in 55.6 and 71.4% of the neurons, respectively, without a significant effect on the membrane potential in 85.7 and 100% of the 5-HT-insensitive neurons. In 5-HT-sensitive neurons, MDL 72222 reversibly abolished the fast depolarization induced by 2-methyl-5-HT; BRL 24924 significantly inhibited the slow depolarization induced by MCPP or 5-OHIP, but not by SP. Prolonged superfusion of 5-HT-sensitive neurons with MCPP abolished the evoked ls-EPSP without inhibition of action potential. These results suggest that the fast and slow depolarizations in these neurons are mediated by 5-HT(3) and 5-HT(1P) receptor subtypes, respectively. The latter may also mediate the ls-EPSP in 5-HT-sensitive neurons.

Effects of rat fetuin on stimulation of bone resorption in the presence of parathyroid hormone

Rat fetuin, which is the rat counterpart of human alpha 2-HS glycoprotein and bovine fetuin, is only detectable in calcified tissues such as bone matrices and dentin, and bone cells such as osteoblasts and osteocytes immunohistochemically. The effect of this protein on bone resorption was examined to study its physiological role in bone metabolism. Rat fetuin increased bone resorption in the presence of low concentrations of parathyroid hormone (PTH), but it had no activity on bone resorption without PTH. The increase in bone resorption by PTH and PTH plus rat fetuin was inhibited by the addition of chymostatin, an inhibitor for cathepsin L. Moreover, we found that when type I collagen from rat was preincubated with rat fetuin, the digestion of rat type I collagen by cathepsin L was increased. These findings suggest that rat fetuin present in bone matrix is important in bone resorption.

[Long-term efficacy of transurethral electrovaporization of the prostate for symptomatic benign prostatic hyperplasia]

OBJECTIVE

To observe long-term efficacy of transurethral electrovaporization of the prostate for symptomatic benign prostatic hyperplasia.

METHODS

Two types of electrode of transurethral electrovaporization of the prostate (TVP) were performed on 150 patients of symptomatic BPH (mean age 74.8 years). The patients were assessed at baseline for both efficacy and followup at 36 months. Efficacy parameters evaluated included operation time (minutes), I-PSS and quality of life score, digital rectal examination, transrectal ultrasound, urodynamics and postvoid residual urine.

RESULTS

36 months after operation, I-PSS was decreased from 24.8 to 5.4 and the quality of life score also was decreased from 4.9 to 2.1. The mean peak uroflow was increased from 9.8 to 18.5 ml/s and postvoid residual urine was decreased from 108 ml to 22 ml (P < 0.05). The mean operation time was 44.7 min. Urodynamic results of 139 cases (92.7%) showed no bladder outlet obstruction, the remaining 11 cases showed severe bladder outlet obstruction to mild obstruction after 36 months. Hematuria was the only complication of our procedure.

CONCLUSIONS

Significant clinical improvement is maintained with minimal morbidity. The long-term efficacy and safety of TVP is satisfactory. TVP is a potential useful procedure for transurethral resection of the prostate.

[A randomized multicentre clinical trial on different doses of mifepristone alone and in combination with anordrin as emergency contraception]

OBJECTIVES

To investigate the effectiveness and side-effects of different doses of mifepristone alone or in combination with anordrin given orally within 96 hours after unprotected intercourse as an emergency contraceptive.

METHODS

2,400 cases of healthy women were recruited and allocated randomly in 4 groups: single dose of 25 mg mifepristone, 25 mg mifepristone plus 7.5 mg anordrin, 10 mg mifepristone plus 5 mg anordrin and 10 mg mifepristone alone. The efficacy rates of contraception were estimated according to Dixon method.

RESULTS

The total expected number of pregnancy was 171.9 for 2,387 subjects enrolled in the study. The number of observed pregnancies related to method failure was 32 cases. The contraceptive effectiveness rates for the above 4 groups were 80.9%, 85.3%, 90.6% and 67.3%, respectively. For the group received 10 mg mifepristone plus 5 mg anordrin, pregnancy rate was 0.7% which was significantly lower than that in 10 mg mifepristone alone group (2.2%, P < 0.05). The incidences of withdrawal bleeding were 9.2%, 4.9%, 3.4% and 6.7% for the 4 group respectively. Two groups received mifepristone in combination with anordrin showed significant lower incidence of withdrawal bleeding than those in mifepristone alone groups.

CONCLUSION

Single oral administration of 25 mg mifepristone alone, and the combination of 10 mg mifepristone plus 5 mg anordrin were safe and effective treatment regimen for emergency contraception with no serious adverse reaction and disturbance on menstrual pattern.

[Serum levels of levonorgestrel during long-term use of Norplant]

OBJECTIVE

(1) Assessment of longest effective contraceptive duration of Norplant (containing levonorgestrel, LNG) by serum levonorgestrel levels. (2) To observe the possible relationships between the serum LNG levels of long-term use (5 years) and body weight.

METHODS

To determine serum LNG levels in 230 women among 1,356 cases at various intervals between 1 and 11 years after implantation using RIA kits provided by WHO.

RESULTS

The average serum levels of LNG in users of Norplant at the 1st, 3rd, 5th years were 1,273.5, 924.0 and 739.6 pmol/L respectively. From the 5th to 7th years average serum LNG levels showed almost a linear decline, and from the 7th through 10th year it did not show much changes. The average serum LNG level was (511.1 +/- 209) pmol/L. A significant negative correlation was found between serum LNG levels and body weight at the 5th years.

CONCLUSION

One set of Norplant implants may provide effective contraception for 8-10 years in women with body weights less than 60 kg.

[Observations on prostate histology in 50 young and middle aged men. Its implication on clinical pathological diagnosis]

OBJECTIVE

To investigate the morphology and the relationship between the prostate and the adjacent structures in order to clarify its significance in histopathological diagnosis.

METHODS

By means of light microscopy, and in part by electron microscopy and immunohistochemistry, the histology of 50 normal prostates were observed.

RESULTS

The parenchymal component can be divided into four zones, i.e. peripheral zone, central zone, transitional zone and periurethral gland region, each characterized by its own anatomical and histological features.

CONCLUSION

This 4 zone division of prostate has more clinical significance than the traditional division of the prostate. A good knowledge of the normal structure of the prostate has great practical significance in pathologic diagnosis.

[Study on standards for safe and health-protective zone in firework plant]

A retrospective investigation on technology and situation in the production of fireworks, the cause and hazard consequences of accidents in blossom firework enterprises was carried out. The risk factors and their origins, the potential effects on surrounding environments and residents, the manufacture processes producing special potential energy in these enterprises were summarized and assessed. In addition, the consequences of explosive fire accidents were assessed retrospectively by the principle of explosion mechanics and Hopkinson Scaling Law. The safe and health-protective zone of the blossom firework plant was suggested.

Thrombin receptor mediated signals induce expressions of interleukin 6 and granulocyte colony stimulating factor via NF-kappa B activation in synovial fibroblasts

OBJECTIVE

To clarify the mechanism of thrombin receptor mediated signal transduction and the induction of cytokines by thrombin stimulation in rheumatoid synovial fibroblasts.

METHODS

Cytokines were measured by enzyme linked immunosorbent assay (ELISA) in the supernatants of cultured rheumatoid synovial fibroblasts stimulated by thrombin. To assess the mechanism of thrombin receptor mediated signal transduction in the rheumatoid synovial fibroblasts, electrophoretic mobility gel shift assay (EMSA), immunoglobulin kappa-chloramphenicol acetyltransferase (CAT) assay, and immunostaining for NF-kappa B subunit molecule was performed.

RESULTS

Thrombin stimulation activated the inducible transcription factor NF-kappa B, and then induced subsequent expressions of interleukin 6 (IL6) and granulocyte colony stimulating factor (G-CSF) in the cells.

CONCLUSION

Thrombin receptor mediated signal transduction could induce the expressions of IL6 and G-CSF, and increase inflammatory events in the cavum articulare via NF-kappa B activation.

[An introductory clinical trial of three-monthly injectable contraceptive-depot medroxyprogesterone acetate]

OBJECTIVE

To evaluate contraceptive efficacy, continuative rate of use, side effects and acceptability of depot medroxyprogesterone acetate (DMPA) injectable contraception preparation in Chinese women.

METHOD

This was an open study. One thousand nine hundred and eighty-five women acquiring contraception received DMPA injection after obtaining informed consent and were followed-up every 3-month up to one year.

RESULTS

The total experience accumulated was 1,731.7 women-year with DMPA for 1,985 users. The one year continuation rate was 77.4%. Three subjects became pregnant, the one year accumulative life table failure rate was 0.2%. The accumulative discontinuation rates at one year for other reasons were amenorrhoea (4.8%), bleeding related (13.4%), other medical reasons (2.6%), other personal reasons (2.1%) and lost to follow-up (1.6%). The main complaints were irregular bleeding, amenorrhoea and prolonged bleeding. Lactating women had significantly lower rate of complaint.

CONCLUSION

DMPA is a highly effective long-acting contraceptive, it could have good acceptability, especially for lactating women, under the well consultation.

Mechanism of depression in cardiac sarcolemmal Na+-K+-ATPase by hypochlorous acid

Oxidative stress during pathological conditions such as ischemia-reperfusion is known to promote the formation of hypochlorous acid (HOCl) in the heart and to result in depression of cardiac sarcolemmal (SL) Na+-K+-ATPase activity. In this study, we examined the direct effects of HOCl on SL Na+-K+-ATPase from porcine heart. HOCl decreased SL Na+-K+-ATPase activity in a concentration- and time-dependent manner. Characterization of Na+-K+-ATPase activity in the presence of different concentrations of MgATP revealed a decrease in the maximal velocity (Vmax) value, without a change in affinity for MgATP on treatment of SL membranes with 0.1 mM HOCl. The Vmax value of Na+-K+-ATPase, when determined in the presence of different concentrations of Na+, was also decreased, but affinity for Na+ was increased when treated with HOCl. Formation of acylphosphate by SL Na+-K+-ATPase was not affected by HOCl. Scatchard plot analysis of [3H]ouabain binding data indicated no significant change in the affinity or maximum binding capacity value for ouabain binding following treatment of SL membranes with HOCl. Western blot analysis of Na+-K+-ATPase subunits in HOCl-treated SL membranes showed a decrease (34 +/- 9% of control) in the beta1-subunit without any change in the alpha1- or alpha2-subunits. These data suggest that the HOCl-induced decrease in SL Na+-K+-ATPase activity may be due to a depression in the beta1-subunit of the enzyme.

Ca2+ mobilization in adult rat cardiomyocytes by angiotensin type 1 and 2 receptors

The role of angiotensin II (AngII) in the regulation of heart function under normal and pathological conditions has been well documented. Although two types of AngII receptors (AT1 and AT2 receptors) are found in equal proportions in the rat heart, most studies have focused primarily on AT1 receptor-coupled events. In this study, the contribution of both types of AngII receptors to cardiac function was evaluated by measuring intracellular calcium ([Ca2+]i) levels at ambient temperature in freshly isolated adult rat ventricular cardiomyocytes. Exposure of cardiomyocytes to AngII (0.01 to 10 microM) resulted in an immediate and sustained increase in [Ca2+]i in a concentration-dependent manner. The increase in [Ca2+]i in cardiomyocytes by AngII was blocked by either losartan or compound PD123319 (1-[[4-(dimethylamino)-3-methylphenyl]methyl]-5-(diphenylacetyl)- 4,5,6,7-tetrahydro-1H-imidazo[4,5-c]pyridine-6-carboxylic acid), non-peptide antagonists of the AT1 and AT2 receptors, respectively. The specificity of the action of these antagonists was verified by their inability to alter the basal levels of [Ca2+]i as well as KCl- or ATP-induced increases in [Ca2+]i. AngII was also observed to initiate spontaneous beating activity in cardiomyocytes, which was prevented by both losartan and compound PD123319 in a concentration-dependent manner (0.01 to 10 microM). These data indicate that the activation of both AT1 and AT2 receptors may stimulate a signalling pathway that influences [Ca2+]i and spontaneous beating activity in cardiomyocytes.

Electrocardiographic Changes and Mortality Due to Myocardial Infarction in Rats With or Without Imidapril Treatment

BACKGROUND: Various angiotensin-converting enzyme inhibitors are known to improve heart function and prolong survival in patients and animals after myocardial infarction. Because myocardial infarction is known to induce arrhythmias, this study tested the hypothesis that early treatment with the angiotensin converting enzyme inhibitor imidapril reduces mortality during acute myocardial infarction because of protective effects against arrhythmogenesis. METHODS AND RESULTS: Rats were randomly divided into four groups: sham control, myocardial infarction, sham plus imidapril, and myocardial infarction plus imidapril. Myocardial infarction was produced by ligation of the left anterior descending coronary artery. Treated rats received imidapril (1 mg/kg/day) through a gastric tube beginning 1 hour after coronary occlusion; control rats received tap water. Electrocardiogram (ECGs) were recorded 1, 3, 7, and 21 days postocclusion. Infarct size and scar weight were determined at 21 days in the myocardial infarction groups with and without imidapril treatment. ECGs of untreated rats showed ST-segment changes, abnormal Q waves, premature ventricular complexes, and QT(c) prolongation 1-21 days after coronary occlusion. Total mortality in 21 days averaged 35% in untreated rats; mortality within 48 hours was 30%. On the other hand, imidapril-treated rats showed fewer ST-segment changes, fewer abnormal Q waves, and a decreased incidence of premature ventricular complexes after coronary occlusion; the ST-segment and QT(c) interval returned to basal values within 1 week after occlusion. Imidapril treatment did not affect the ECG pattern in sham-treated control animals. Total mortality in the imidapril-treated group in 21 days after infarction was 22.5%; mortality within 48 hours was 20% (P <.05 compared with the untreated infarction group). Infarct size and scar weight caused by coronary occlusion did not differ in the untreated and imidapril-treated groups. CONCLUSIONS: Early treatment with imidapril markedly decreases mortality in rats after acute myocardial infarction. The lower mortality is not associated with a decrease in infarct size but is consistent with a protective effect of the drug against arrhythmogenesis.

Fura-2 fluorescent technique for the assessment of Ca2+ homeostasis in cardiomyocytes

Ca2+ homeostasis plays a pivotal role in maintaining cell growth and function. Many heart diseases are related to the abnormalities in Ca2+ mobilization and extrusion. Ca2+-sensitive fluorescent dyes have been used successfully to estimate intracellular free Ca2+ ([Ca2+]i) level and the mechanisms of Ca2+ movements in living cells. This article is focused on the methodology involving the use of Fura-2/AM or free Fura-2 to measure agonist-induced Ca2+ mobilization as well as the mechanisms of changes in [Ca2+]i in cardiomyocytes. Methods involving Fura-2 technique for the measurement of Ca2+ extrusion from the cells and Ca2+ reuptake by sarcoplasmic reticulum (SR) are also described. The prevention of KCl-induced increase in the intracellular Ca2+ is shown by chelating the extracellular Ca2+ with EGTA or by the presence of Ca2+-channel inhibitors such as verapamil and diltiazem. The involvement of SR in the ATP-induced increase in intracellular Ca2+ is illustrated by the use of Ca2+-pump inhibitors, thapsigargin and cyclopiazonic acid as well as ryanodine which deplete the SR Ca2+ storage. The use of 2-nitro-4-carboxyphenyl N,N-diphenyl carbamate (NCDC), an inhibitor of inositol 1,4,5-trisphosphate (IP3) production, is described for the attenuation of phosphatidic acid (PA) induced increase in Ca2+-mobilization. The increase in intracellular Ca2+ in cardiomyocytes by PA, unlike that by KCl or ATP, was observed in diabetic myocardium. Thus, it appears that the Fura-2 method for the measurement of Ca2+ homeostasis in cardiomyocytes is useful in studying the pathophysiology and pharmacology of Ca2+ movements.

Differential changes in sympathetic activity in left and right ventricles in congestive heart failure after myocardial infarction

Although congestive heart failure subsequent to myocardial infarction is known to be associated with increased sympathetic activity, very little information regarding changes in the sympathetic nerves in the left and right ventricles at various stages after infarction is available. Male Sprague-Dawley rats were subjected to coronary artery ligation and studied 4 and 8 weeks later; these animals had mild and moderate stages of congestive heart failure. A sham group, without coronary ligation, was used as control. Four weeks after myocardial infarction, plasma and ventricular (left and right) epinephrine (EPI), unlike norepinephrine (NE), were markedly increased. Whereas plasma catecholamine (EPI and NE) levels were increased 8 weeks after infarction, NE concentration in the left ventricle was unchanged but EPI concentration was increased in comparison with sham control. The right ventricle showed an increased level of both NE and EPI 8 weeks after infarction. Measurement of the rate of change in the specific activity of NE (NE turnover) in the left and right ventricles 8 weeks after infarction revealed an increase in NE turnover in the left ventricle, without any changes in the right ventricle. The concentration of EPI, unlike NE, was increased in the kidney, spleen, and brain 8 weeks after coronary occlusion. These results are interpreted to mean that congestive heart failure caused by myocardial infarction is associated with differential changes in the status of sympathetic nerves in the left and right ventricles; sympathetic activity is increased only in the left ventricle, whereas the right ventricle may play an adaptive role by increasing catecholamine stores during the development of heart failure.

Adolescent dieting: healthy weight control or borderline eating disorder?

Dieting in adolescent girls is ubiquitous but its health significance is uncertain. On the one hand it might be seen as promoting healthy weight control and on the other it might be considered as a risk factor for eating disorders. Dieting levels were systematically assessed in a representative group of 2525 Australian teenagers and classified using item response theory. In this group, 38% of girls and 12% of boys were categorised as intermediate dieters; 7% of girls and 1% of boys fell into a group of extreme dieters. Body mass carried a strong positive association with intermediate dieting. Most female dieters, nevertheless, fell within a normal weight range. Psychiatric morbidity was the clearest factor associated with extreme dieting and 62% of extreme dieters reported high levels of depression and anxiety. Extreme dieting might reasonably be viewed as lying on a spectrum with clinical eating disorders. Most dieting is unjustified on the grounds of appropriate weight control and appears to reflect a widespread striving of teenage girls towards body shapes at the lower end of age-adjusted norms.

Menarche and the onset of depression and anxiety in Victoria, Australia

STUDY OBJECTIVE

Psychiatric disorder often begins at adolescence. This study aimed to examine the associations between puberty and social circumstances and the adolescent rise in depression and anxiety.

DESIGN

A two stage cluster sampling procedure was used to identify a representative group of Australian secondary school students in years 7 (age 12-13 years), 9 (14-15 years), and 11 (16-17 years) of 45 Victorian schools. The computerised clinical interview schedule (CIS) was used to evaluate psychiatric morbidity.

MAIN RESULTS

A total of 2525 subjects completed the survey - an overall participation rate of 83%. Levels of depression and anxiety increased with the secondary school years and girls had significantly higher rates at each school year level. For boys, the clearest independent associations with depression and anxiety were rising school year level and high parental educational achievement. For girls menarchal status emerged as the strongest predictor. Associations with age and school year level, evident on univariate analysis, did not persist when the recency of menarche was taken into account. After addition of measures of perceived social stress to a multivariate model, a significant association between depression/anxiety and parental divorce disappeared but the association with menarche persisted.

CONCLUSIONS

Menarche marks a transition in the risk of depression and anxiety in girls. The pattern of findings is consistent with a biological mediation of this association.

Phosphatidic acid increases intracellular free Ca2+ and cardiac contractile force

Although phosphatidic acid (PA) is mainly formed due to the hydrolysis of phosphatidylcholine by myocardial phospholipase D, its functional significance in the heart is not fully understood. The present study was designed to determine the effects of PA on intracellular free Ca2+ level ([Ca2+]i) in freshly isolated adult rat cardiomyocytes by using fura 2-acextoxmethylester and free fura 2 technique. Addition of PA at concentrations of 1-200 microM produced a concentration-dependent increase in [Ca2+]i from the basal level of 117 +/- 8 nM; maximal increase in [Ca2+]i was 233 +/- 50 nM, whereas median effective concentration (EC50) for PA was 45 +/- 1.2 microM. This increase in [Ca2+]i was abolished by the removal of extracellular Ca2+ with ethylene glycol-bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid and was partially attenuated by Ca2+ channel blockers, verapamil or diltiazem. Preincubation of cardiomyocytes with cyclopiazonic acid and thapsigargin or with ryanodine [to deplete sarcoplasmic reticulum (SR) Ca2+] attenuated the PA-induced increase in [Ca2+]i by 66, 37, and 43%, respectively. Furthermore, the response of [Ca2+]i to PA was blunted by 2-nitro-4 carboxyphenylcarbonate, an inhibitor of phospholipase C, but was unaffected by staurosporine, a protein kinase C inhibitor. PA was also observed to induce Ca2+ efflux from the myocytes. In addition, an injection of PA (0.34 microgram/100 g body wt i.v.) in rats produced a significant increase of the left ventricular developed pressure as well as the maximum rates of cardiac contraction and relaxation within 5 min. These data suggest that the PA-induced increase in [Ca2+]i in cardiomyocytes is a consequence of both Ca2+ influx from the extracellular source and Ca2+ release from the intracellular SR stores. Furthermore, these in vitro data suggest the possibility that PA may regulate [Ca2+]i and contractile parameters in the heart.

Neuropeptide Y modulation of sympathetic activity in myocardial infarction

OBJECTIVES

We examined the possible effect of neuropeptide Y in modulating central sympathetic activity after myocardial infarction in rats.

BACKGROUND

Previous studies have shown the coexistence of neuropeptide Y and norepinephrine in the brain and a possible functional interaction between the two. Neuropeptide Y inhibits the release of norepinephrine at the presynaptic level and can be considered to act as a neuromodulator.

METHODS

Two groups of rats were examined in this study-an experimental group, defined as those rats undergoing left coronary artery ligation, and a sham group without coronary artery ligation, serving as the control group. The animal in both groups underwent microdialysis in the paraventricular nucleus at 2, 4 and 8 weeks after operation. Microdialysis samples were collected with and without injecting neuropeptide Y in the paraventricular nucleus. The concentration of norepinephrine was determined by injecting purified microdialysate samples during high performance liquid chromatography. To explore the receptor's possible role, autoradiographic localization of neuropeptide Y receptors in the paraventricular nucleus was also carried out in the experimental and sham groups.

RESULTS

The concentration of norepinephrine measured in the samples was decreased by 50% with neuropeptide Y in 2- and 4-week old rats after infarction, but by only 20% (p < 0.05) in 8-week old rats after infraction. The diminished inhibitory effects of neuropeptide Y on norepinephrine release was associated with increased sympathetic activity, as reflected by plasma norepinephrine; 8-week old rats after infarction had almost a 100% (p < 0.05) increase in their plasma norepinephrine level compared with the sham group. Autoradiography revealed a significant decrease in density of neuropeptide Y receptors in the paraventricular nucleus in 8-week old rats after infarction (p < 0.05).

CONCLUSIONS

The data presented in this report suggest that the reduction of the inhibitory activation of neuropeptide Y on sympathetic release may contribute to elevated norepinephrine levels after myocardial infarction.

Effect of hepatocyte growth factor/scatter factor on lipogenesis in adult rat hepatocytes in primary culture

Hepatocyte growth factor (HGF)/scatter factor is known to be the most potent mitogen for hepatocytes. In this paper, we report that lipogenesis in primary cultured rat hepatocytes treated with 10 ng/ml of recombinant human HGF (rhHGF) for 24 h was stimulated, as measured by the incorporation of 3H2O into long-chain fatty acids, to more than twice as much as the control. Insulin (0.1 microM) was more effective than rhHGF but rhHGF did not show an additive or synergistic effect when added to insulin. We also showed that treatment with rhHGF increased the activities of glucose-6-phosphate dehydrogenase (G6PDH) and malic enzyme, key enzymes which supply NADPH for lipogenesis, and acetyl-CoA carboxylase, the rate-limiting enzyme of lipogenesis. The increase in G6PDH and acetyl-CoA carboxylase activities was accompanied by increases in the levels of mRNA for the enzymes. These results suggest that HGF is involved in liver regeneration not only by stimulation of cell proliferation but also by acceleration of differentiation of hepatocytes.

[A phase III multicentre study on medical termination of early pregnancy with two regimens of mifepristone followed by PG05]

OBJECTIVE

To compare use-effectiveness and side-effects of medical termination of early pregnancy by oral administration of separated doses of mifepristone 150 mg or single dose of mifepristone 200 mg followed by PG05 1 mg vaginally in 4500 healthy pregnant women with amenorrhea < or = 49 days in a phase I multicentre study.

METHODS

All subjects were recruited in 30 clinics after obtaining informed consents.

RESULTS

The complete, incomplete abortion and continuous pregnancy rates were 88.6%, 8.1%, 1.7% and 92.0%, 5.8%, 0.8% in single dose and separated doses groups, respectively. The efficacy of termination of early pregnancy by mifepristone 150 mg in separated doses was higher than that in single dose of mifepristone 200 mg when both in combination with PG05 1 mg (P < 0.01). One case of allergic rash was noted after administration of mifepristone. No severe side-effects were observed except bleeding problems. 65 cases received emergency vacuum aspiration and 7 of them received blood transfusion due to heavy bleeding. In addition, 2 cases of ectopic pregnancies required blood transfusion as heavy bleeding caused by exfetation disruption. There was no significant difference in to the time to start bleeding and the days of bleeding lasted between two treatment groups. However, there was a significant positive correlation (P < 0.001) between diameters of SAC and the days of bleeding lasted.

CONCLUSIONS

Logistic regression analysis suggested that subject's age, gravidity and days of amenorrhea have significant effects on abortion efficacy. 75.2% of subjects are satisfactory in self-assessment of the treatment, and 81.8% of subjects will choose medical abortion method in case they need to terminate undesired early pregnancy in the future.

Myosin light chain phosphorylation in cardiac hypertrophy and failure due to myocardial infarction

The regulatory myosin light chain (MLC) is phosphorylated in cardiac muscle by Ca2+/calmodulin dependent myosin light chain kinase (MLCK) and is considered to play a modulatory role in the process of force generation. In order to determine changes in MLC phosphorylation in cardiac hypertrophy and heart failure, the relative content of MLCK and MLC phosphorylation in the cardiac muscle from both sham control and experimental rats were assessed at 4 and 8 weeks following ligation of the left coronary artery. Changes in the relative MLCK content were measured by electrophoresis and immunoblot assay whereas phosphorylated and unphosphorylated MLC were separated by non-denaturing 10% acrylamide/urea gel and identified by Western blotting. The relative amount of MLCK was increased by 20-35% in the viable left ventricle, right ventricle and septum from the 8-week experimental rats in comparison to the respective control values. The MLC phosphorylation increased significantly in the right ventricle and septum but decreased markedly in the viable left ventricle from 8-week experimental rats in comparison to the control values. No appreciable changes in the relative amount of MLCK and MLC phosphorylation were seen between control and experimental rats at 4 weeks. These results suggest duration and region specific changes in the levels of MLCK and MLC phosphorylation in cardiac hypertrophy and heart failure subsequent to myocardial infarction.

Inhibition of cardiac sarcolemma Na(+)-K+ ATPase by oxyradical generating systems

The Na(+)-K+ ATPase activity and SH group content were decreased whereas malondialdehyde (MDA) content was increased upon treating the porcine cardiac sarcolemma with xanthine plus xanthine oxidase, which is known to generate superoxide and other oxyradicals. Superoxide dismutase either alone or in combination with catalase and mannitol fully prevented changes in SH group content but the xanthine plus xanthine oxidase-induced depression in Na(+)-K+ ATPase activity as well as increase in MDA content were prevented partially. The Lineweaver-Burk plot analysis of the data for Na(+)-K+ ATPase activity in the presence of different concentrations of MgATP or Na+ revealed that the xanthine plus xanthine oxidase-induced depression in the enzyme activity was associated with a decrease in Vmax and an increase in Km for MgATP; however, Ka value for Na+ was decreased. Treatment of sarcolemma with H2O2 plus Fe2+, an hydroxyl and other radical generating system, increased MDA content but decreased both Na(+)-K+ ATPase activity and SH group content; mannitol alone or in combination with catalase prevented changes in SH group content fully but the depression in Na(+)-K+ ATPase activity and increase in MDA content were prevented partially. The depression in the enzyme activity by H2O2 plus Fe2+ was associated with a decrease in Vmax and an increase in Km for MgATP. These results indicate that the depressant effect of xanthine plus xanthine oxidase on sarcolemmal Na(+)-K+ ATPase may be due to the formation of superoxide, hydroxyl and other radicals. Furthermore, the oxyradical-induced depression in Na(+)-K+ ATPase may be due to the formation of superoxide, hydroxyl and other radicals.(ABSTRACT TRUNCATED AT 250 WORDS)

A transmission model for a disease with some fatalities

A stochastic epidemic model which allows some infected individuals to die from the disease is considered. The model includes the general epidemic and the fatal disease model as particular cases. A set of iterative equations is derived from which the probability distribution of the final size of the epidemic can be computed. It is illustrated that the fatal disease model is distinct in that it results in nearly all or hardly anyone being infected in a large population. An easily computed estimator for a key parameter of the model is derived and it is illustrated that it has good efficiency relative to the maximum likelihood estimator, which is very tedious to compute.

Characterization of the translocation process of vitamin D3 from the skin into the circulation

The cutaneous synthesis of vitamin D3 and the subsequent translocation of vitamin D3 into the circulation are two key steps in the vitamin D endocrine system. To study the kinetic aspects of cutaneous synthesis and translocation of vitamin D3, both in vitro and in vivo chicken models have been developed. To assess the capacity of chicken skin to generate vitamin D3, the concentrations of 7-dehydrocholesterol (7-DHC) in different skin areas were determined. It was found that the highest concentration of 7-DHC was in the leg skin (3524 +/- 937 ng cm-2), which was about 30 times greater than that in the back (120 +/- 62 ng cm-2). Whole body exposure of chickens to UV-B radiation (0.5 J cm-2) resulted in the production of previtamin D3 (preD3) in the skin of the legs and feet (43 +/- 7 and 54 +/- 17 ng cm-2, respectively), whereas no preD3 was detected in the back skin. In vitro, at 40 C, the forward (k1) and reverse (k2) rate constants of the preD3<-->vitamin D3 reaction in the leg skin were greatly increased compared to those in n-hexane (k1, 0.367 vs. 0.0369 h-1; k2, 0.042 vs. 0.0059 h-1). In vivo, the determined rate constants k1, k2, and k3 for the consecutive reactions preD3<-->vitamin D3-->vitamin D3 were 0.257, 0.034, and 0.114 h-1, respectively. To evaluate the circulating concentration of vitamin D3 in response to UV-B radiation, chicken legs were irradiated. The time course revealed a 4-fold increase in the circulating concentration of vitamin D3, with a peak about 30 h postradiation. No appreciable amount of preD3 could be detected in the circulation in the early hours after UV-B radiation, suggesting the existence of a process responsible for the specific translocation of vitamin D3 from the skin into the circulation.

Growth of lactobacilli, Staphylococcus aureus and Escherichia coli in normal and mastitic milk and whey

The growth of three lactobacilli (Lactobacillus acidophilus, L. bulgaricus and L. casei), Staphylococcus aureus and Escherichia coli was followed in normal and mastitic milk and whey using the standard plate count method. L. acidophilus, L. bulgaricus 6032 and L. casei 6028 grew well in normal milk, but had decreased growth in mastitic milk if not pre-adapted in mastitic whey. S. aureus 26003 and E. coli 44102 showed enhanced growth in mastitic milk as compared with their growth in normal milk. These mastitis pathogens grew faster than the lactobacilli in both the normal milk and the mastitic milk. Among the lactobacilli, L. acidophilus and L. bulgaricus grew faster than L. casei in both types of milk samples. All the bacteria tested grew well in the normal and mastitic whey samples. However, they seemed to have enhanced growth in mastitic whey with the exception of L. casei. Pre-adaptation of the bacteria in mastitic whey in subculture markedly improved the growth of both pathogenic and non-pathogenic bacteria in mastitic milk. All the bacteria showed decreased replication in mastitic milk as compared with mastitic whey.

[A study of regenerating liver protects against carbon tetrachloride injury in rat]

In our previous study we had demonstrated that regenerating liver of rats had an ability to resist CCl4 injury. In this paper, the underlying mechanism was further investigated. Hepatic stimulator substance from regenerating liver (rHSS) at different time after partial (68%) hepatectomy was extracted and assayed for its biological activity by using 3H-thymidine. The activity is approximately seven-fold as compared with the control. Then, rHSS was given to rats to observe its effect against CCl4 injury both in vivo and in vitro. The results were as follows: rHSS decreases the mortality of CCl4 intoxicated rats and suppresses the elevation of serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) induced by CCl4 in vivo. Also rHSS increases the cell viability and decreases the leakage of intracellular ALT of hepatocytes poisoning by CCl4. The above mentioned results suggest rHSS is an important mechanism for regenerating liver to protect against CCl4 poisoning.