Naringenin inhibits migration of lung cancer cells via the inhibition of matrix metalloproteinases-2 and -9

Lung cancer is among the most common causes of cancer-related mortality. It has a high mortality rate and resistance to chemotherapy due to its high metastatic potential. Naringenin, a bioactive compound identified in several fruits, displays anti-inflammatory and antitumor effects. Furthermore, naringenin mitigates the migration of several human cancer cell types. However, the effects of naringenin on lung cancer remain unclear. The current study investigated the mechanisms of naringenin on the migration of lung cancer A549 cells. The results indicate that significant alteration in A549 cell proliferation was observed in response to naringenin (0-300 µM) treatment for 24 and 48 h. Furthermore, a dose-dependent migration inhibition of A549 in the presence of naringenin was observed by healing and transwell migration assays. In addition, a zymography assay revealed that naringenin exhibited a concentration-dependent inhibition of matrix metalloproteinase (MMP)-2 and -9 activities. Furthermore, naringenin also inhibited the activities of AKT in a dose-dependent manner. These observations indicated that naringenin inhibited the migration of lung cancer A549 cells through several mechanisms, including the inhibition of AKT activities and reduction of MMP-2 and -9 activities.

The extract of Rhodobacter sphaeroides inhibits melanogenesis through the MEK/ERK signaling pathway

Reducing hyperpigmentation has been a big issue for years. Even though pigmentation is a normal mechanism protecting skin from UV-causing DNA damage and oxidative stress, it is still an aesthetic problem for many people. Bacteria can produce some compounds in response to their environment. These compounds are widely used in cosmetic and pharmaceutical applications. Some probiotics have immunomodulatory activities and modulate the symptoms of several diseases. Previously, we found that the extracts of Rhodobacter sphaeroides (Lycogen™) inhibited nitric oxide production and inducible nitric-oxide synthase expression in activated macrophages. In this study, we sought to investigate an anti-melanogenic signaling pathway in α-melanocyte stimulating hormone (α-MSH)-treated B16F10 melanoma cells and zebrafish. Treatment with Lycogen™ inhibited the cellular melanin contents and expression of melanogenesis-related protein, including microphthalmia-associated transcription factor (MITF) and tyrosinase in B16F10 cells. Moreover, Lycogen™ reduced phosphorylation of MEK/ERK without affecting phosphorylation of p38. Meanwhile, Lycogen™ decreased zebrafish melanin expression in a dose-dependent manner. These findings establish Lycogen™ as a new target in melanogenesis and suggest a mechanism of action through the ERK signaling pathway. Our results suggested that Lycogen™ may have potential cosmetic usage in the future.

The -308G/A of Tumor Necrosis Factor (TNF)-α and 825C/T of Guanidine Nucleotide Binding Protein 3 (GNB3) are associated with the onset of acute myocardial infarction and obesity in Taiwan

Acute myocardial infarction is a highly prevalent cardiovascular disease in Taiwan. Among several etiological risk factors, obesity and inflammation are strongly associated with the frequency of hypertension, cardiovascular disease, diabetes, and myocardial infarction. To discriminate obesity- and inflammation-related genes and the onset of acute myocardial infarction (AMI), a case-control study was conducted to investigate the association of the -308G/A polymorphisms of tumor necrosis factor (TNF)-α and the C825T polymorphism of guanidine nucleotide binding protein 3 (GNB3) with the onset of AMI among Taiwanese cohorts. A total of 103 AMI patients and 163 matched normal control samples were enrolled in the present study. The genomic DNA was extracted and subjected into polymerase chain reaction-based restriction fragment length polymorphism (PCR-RFLP) analysis. An association between the A homozygosity of the TNF-α-308G/A polymorphism and the onset of AMI was observed among the male subjects (p = 0.026; Spearman index = 0.200, p = 0.008). An association between the T homozygosity of GNB3 C825T polymorphism and obesity was also observed (Fisher’s exact, p = 0.009). The TT genotype has a protective effect against acquiring AMI among the obese female population in Taiwan (Fisher’s exact, p = 0.032). In conclusion, TNF-α-308G/A and the GNB3 C825T polymorphisms are associated with obesity and AMI in the Taiwanese population.

Association of estrogen receptor α gene PvuII and XbaI polymorphisms with non-small cell lung cancer

Single nucleotide polymorphisms (SNPs) of the estrogen receptor (ER)-α have been found to be associated with various diseases at significantly different frequencies. However, whether any relationship exists between ER-α polymorphisms and lung cancer remains to be determined. In this study, 84 non-smoking, female, non-small cell lung cancer patients with various stages of disease and 234 cancer-free reference controls were enrolled to examine the association of ER-α polymorphisms in lung cancer. Two restriction SNP sites, PvuII and XbaI, in the first intron of the ER-α gene were genotyped by polymerase chain reaction-restriction fragment length polymorphism. The frequencies of the PvuII-XbaI haplotypes and genotypes in a Taiwanese population were revealed for the first time. Although the genotypic frequencies of two polymorphic sites of ER- α were in linkage disequilibrium for the lung cancer group (χ(2)=50.013, d.f.=4) and reference controls (χ(2)=60.797, d.f.=4); and 7 and 8 combined genotypes were present, respectively, the distribution and the major genotypes are different in the two groups (p<0.0001). The p-values for PvuII and XbaI genotypes were significantly different between the lung cancer and reference controls. The PP genotype presence was found to be significantly lower in the lung cancer group (P=0.005), whereas presence of the xx genotype was significantly higher (P=0.042). These findings suggested that the PP genotype had a lower risk of lung cancer; whereas the xx genotype had a higher risk. In comparison with other studies conducted in various populations, it is of note that the pX haplotype frequency of this study was higher than that of other studies, whereas the px haplotype was lower. Moreover, the Xx genotypic frequency of XbaI polymorphisms in the ER-α gene of the reference control group was found to be extremely high, whereas the xx genotypic frequency was extremely low. In conclusion, PvuII-XbaI polymorphisms of the ER-α gene were found to be associated with the risk, but not cancer severity, of non-small cell lung cancer in a Taiwanese population.

p53 codon 72 polymorphism and susceptibility malignancy of colorectal cancer in Taiwan

PURPOSE

The p53 tumor suppressor gene plays two important roles in genomic stability: blocking cell proliferation after DNA damage until it has been repaired, and starting apoptosis if the damage is too critical. A recent report suggests that a polymorphism of the p53 tumor suppressor gene that results in the substitution of a proline residue with an arginine residue at position 72 of the p53 protein might act as a risk factor in the malignant transformation of colorectal adenoma to cancer.

METHODS

In our study, the samples consisted of 150 patients were analyzed for the mutation in the p53 gene. The age of 150 patients (46 women and 104 men) ranged from 30 to 91 years (mean age 68.46 years).

RESULTS

The polymorphism showed 52.04% mutant in the codon 72 of exon 4 in the Taiwanese population. Both of the chi-square for trend test (chi-square = 4.97, p = 0.034) and logistic regression (p = 0.037, odds ratio = 1.699) showed significant differences in the distribution of polymorphism of codon 72 in the p53 gene and Dukes classification of colorectal cancer.

CONCLUSIONS

There were significant relationship between the polymorphism of codon 72 and the malignancy of colorectal cancer in Taiwanese population. There is 1.70 times in each grade change (Dukes A-D) more risk of CCC polymorphism than that of CCG polymorphism of codon 72 of exon 4.

Mutations in the p53 tumor suppressor gene in colorectal cancer in Taiwan

Mutations in the tumor suppressor gene p53 have been reported as occurring prevalently in a wide range of human tumors. Detection of a mutated p53 is thought to provide useful information for the clinical management of colorectal neoplasm. In this study, we used polymerase chain reaction/single-strand conformation polymorphism (PCR/SSCP) and sequencing analysis to rapidly screen for mutations in p53 in colorectal cancer in Taiwan. Genomic DNA was purified from colorectal cancer specimens obtained from 80 patients at a teaching hospital in southern Taiwan. Primer sets were designed to amplify fragments within exons 4-8 of p53. We found p53 mutations in 38 of 80 patients. This is the first identification of a mutation at codon 143 of p53 in colorectal cancer in Taiwan. In addition, we found two insertions in exon 5 of p53. The p53 mutation rate among colorectal tumors in Taiwan, found in this study, is 43%. The results indicate that p53 mutation is not significantly associated with tumor grade, age, or gender (p > 0.05). We found that two-fifths of colorectal cancer patients in Taiwan have a p53 mutation, which could be used as a marker of colorectal cancer.

Effects of methanol-containing additive on emission characteristics from a heavy-duty diesel engine

This study was aimed to investigate the effect of methanol-containing additive (MCA) on the regulated emissions of hydrocarbons (HC), carbon monoxide (CO), nitrogen oxides (NOx), particulate matter (PM), as well as the unregulated carbon dioxide (CO2) and polycyclic aromatic hydrocarbons (PAHs) from a diesel engine. The engine was tested on a series of diesel fuels blended with five additive levels (0, 5, 8, 10 and 15% of MCA by volume). Emissions tests were performed under both cold- and hot-start transient heavy-duty federal test procedure (HD-FTP) cycles and two selected steady-state modes. Results show that MCA addition slightly decreases PM emissions but generally increases both THC and CO emissions. Decrease in NOx emissions was found common in all MCA blends. As for unregulated emissions, CO2 emissions did not change significantly for all MCA blends, while vapor-phase and particle-associated PAHs emissions in high load and transient cycle tests were relatively low compared to the base diesel when either 5 or 8% MCA was used. This may be attributed to the lower PAHs levels in MCA blends. Finally, the particle-associated PAHs emissions also showed trends quite similar to that of the PM emissions in this study.

Expression of functional type 1 protease-activated thrombin receptors by mouse primary palatal mesenchymal cells in vitro

Development of the primary palate involves a series of processes including cell growth, differentiation, and morphogenesis. To study the molecular and cellular processes during mouse primary palatogenesis, mesenchymal cells were isolated from the primary palate of BALB/cBy embryos (day-11, hour 20). Most of the primary palatal mesenchymal (PPM) cells were morphologically similar to fibroblasts. The population doubling time was about 36 h. At concentrations of 5 and 10 unit/ml, alpha-thrombin significantly stimulated the proliferation of these palatal cells by 2- to 2. 4-fold compared to untreated controls over a 72 hour incubation period. Reverse transcriptase-polymerase chain reaction using primers based on the mouse type 1 protease-activated thrombin receptor (PAR1) detected PAR1 mRNA in the PPM cells, the authenticity of which was confirmed by partial DNA sequencing. Blocking of the alpha-thrombin proteolytic site with the highly specific inhibitor D-phenylalanyl-prolyl-arginyl chloromethyl ketone significantly suppressed the mitogenic effect of thrombin on the PPM cells by 71%. These results suggest that PAR1 is present on PPM cells in the mouse embryo and that serine protease activity is important for the receptor activation.

Effect of methanol-containing additive on the emission of carbonyl compounds from a heavy-duty diesel engine

This study was aimed at determining the effect of methanol-containing additive (MCA) on the emission of carbonyl compounds (CBCs) generated from the diesel engine. For this experiment, a heavy-duty diesel engine was connected with a full flow critical flow ventri (CFV) type dilution tunnel, a Schenck GS-350 DC dynamometer, and a DC-IV control system in series. The operating conditions of the heavy-duty diesel engine for both cold-start and hot-start Transient Cycle tests and for both low-load and high-load steady-state tests were ascertained. The exhaust of CBCs collected from a 2,4-dinitrophenylhydrazine (2,4-DNPH)-coated cartridge were first converted to corresponding hydrazone derivatives, which were then solvent-eluted and analyzed by a High Performance Liquid Chromatograph (HPLC) with an ultraviolet-visible (UV) detector. When either 10% or 15% MCA was used, the emission factors of the CBCs acrolein and isovaleraldehyde increased by at least 91%. Accordingly, future studies must be done to cut down the emission of CBCs when MCA and methanol alternative fuels are used.

Pegylated liposomal doxorubicin in treating a case of advanced hepatocellular carcinoma with severe hepatic dysfunction and pharmacokinetic study

BACKGROUND

There is lack of effective and safe chemotherapy for advanced hepatocellular carcinoma. Polyethylene glycol-coated (pegylated) liposomal doxorubicin (PLD) has long circulation time and enhanced drug accumulation in the tumor tissues. It has significant activity in Kaposi's sarcoma, breast and ovarian cancers and the acute adverse effects of free drug are reduced.

PATIENTS AND METHODS

A patient with advanced hepatocellular carcinoma was treated with PLD and a pharmacokinetic study was performed. Initial serum total and direct bilirubin were 3.6 and 6.8 folds of upper normal, respectively, and an indocyanine green clearance test at 15 minutes was 26.3% (normal < 15%).

RESULTS

Compared to cases with normal liver function, increased volume of distribution of doxorubicin correlated with a large amount of ascites (P < 0.05). The clearance of drug was unexpectedly higher than in cases with normal liver function (P < 0.05). According to the pharmacokinetic studies, the disposition of PLD in this case has not been retarded even in the presence of severe liver dysfunction. Only minimal toxicities including grade 2 stomatitis and moderate leukopenia were observed. The tumor had a partial remission and the patient survived nine months after PLD treatment.

CONCLUSION

PLD could serve as a safe and effective treatment for hepatocellular carcinoma even in the presence of impaired liver function. Its role in treating advanced hepatocellular carcinoma is worthy of further study.

Emission characteristics of VOCs from athletic tracks

Dynamic and flow-through flux chambers are convenient tools for field measurements of gas or VOC emission flux from solid surfaces in the field. This study was undertaken to collect on site and quantify the emissions of volatile organic compounds (VOCs) released from athletic running tracks. Three typical types of tracks, one synthetic rubber and two tracks (types I and II) consisting mainly of polyurethane, were studied. They were all installed with adhesives and backings, both of which contributed significant amount of VOCs. VOCs released from the track surface were collected with a flux chamber and subsequently analyzed by a gas chromatograph/mass spectrometer (GC/MS). Also, for each track and at each selected time the emission flux and mass emission were measured on site under outdoor conditions over a period of 40 min. GC/MS analyses show that the VOCs emitted include 2-methyl furan, butanal, methyl ethyl ketone, benzene, heptane, methyl isobutyl ketone, toluene+octane, hexanal, nonane+ethylbenzene, xylenes+styrene, propyl benzene, decane, 1,3,5-trimethyl benzene, 1,2,4-trimethyl benzene, 1,2, 3-trimethyl benzene and undecane. Of these, hexanal was the common and principal compound for all three types of tracks. 2-Methyl furan and methyl isobutyl ketone were the characteristic compounds for the synthetic rubber and the type II of polyurethane tracks, respectively. In the field studies, no unique compounds were found in the type I of polyurethane tracks. For each of these three types of tracks the total-VOCs emission flux was correlated to the track age and track surface temperature. The results of multiple regression analysis showed good correlation. The type II polyurethane track had the highest decay rate, while the synthetic rubber track had the lowest decay rate. Two years after the track installation, the VOC concentrations measured at 1.5 m above the track, the breathing height of school children, were not significantly higher than the background levels.

Direct comparison of liposomal doxorubicin with or without polyethylene glycol coating in C-26 tumor-bearing mice: is surface coating with polyethylene glycol beneficial?

Sterically stabilized liposome is characterized by a surface coating of polyethylene glycol (PEG) or other polymers that can reduce opsonization of the liposome by plasma proteins. It has a higher plasma area under the concentration-time curve (AUC), which is believed to correlate with better therapeutic efficacy. However, the presence of large molecules on the liposomal surface may reduce the interactions of liposomes with cells and hinder entry of liposomes into the tumor tissue. Using a stable liposomal system composed of distearoyl phosphatidylcholine/cholesterol, we examined the effect of PEG (Mr 2000) on the pharmacokinetics and on the efficacy of liposomal doxorubicin with C-26 syngeneic tumor model in BALB/c mice. The plasma AUC of liposomal doxorubicin with 6 mol-% PEG-modified distearoyl phosphatidylethanolamine (PEG-DSPE) was approximately twice that of liposomal doxorubicin without PEG at various dosages, regardless of whether the mice were tumor-bearing. Paradoxically, the group of mice treated with liposomal doxorubicin without PEG had higher tumor doxorubicin concentrations. The 72-h tumor AUC was 1.44 times that of liposomal doxorubicin with 6% PEG-DSPE. The tumor-accumulation efficiency (AUC(Tumor)/AUC(Plasma)) of liposomal doxorubicin without PEG was 0.87, and this was more than twice that of the liposomal doxorubicin with 6% PEG-DSPE (0.31). At a dose of 10 mg/kg, although both liposomal groups were better than the free drug group in terms of clinically relevant parameters, including toxicity, tumor shrinkage, and survival, there was no difference between the two liposomal drug groups. In this stable liposome system, surface coating with PEG offered no benefit for liposomal doxorubicin in the C-26 tumor model. To enhance the therapeutic index of liposomal doxorubicin, simply increasing plasma AUC by surface coating with PEG may not be satisfactory.

The rescue effect of 15-deoxyspergualin on intraperitoneal microencapsulated xenoislets

Because the development of surface neogrowth composed mainly of macrophages and fibroblasts precedes the recurrence of hyperglycemia in treated diabetic animals, the pericapsular macrophages may adversely affect the graft function of i.p. alginate-poly-L-lysine-alginate (A-P-A) microencapsulated islets. In order to clarify the role of pericapsular macrophages on late islet xenograft dysfunction, we investigated whether 15-deoxyspergualin (15-DSG), a macrophage inhibitor, has a rescue effect on the recurrent hyperglycemia in streptozotocin-induced diabetic mice that had been treated with i.p. transplantation of A-P-A microencapsulated rat islets. The mean duration of normoglycemia (whole blood glucose level below 8.3 mmol/l) in streptozotocin-induced diabetic mice treated with implantation of about 2200-2400 of A-P-A microencapsulated rat islets was 75 days. When the blood glucose levels were higher than 11.1 mmol/l for two consecutive determinations, 15-DSG at a dose of 0.625 mg/kg body weight or isotonic sodium chloride solution (control group) was given daily s.c.. The blood glucose levels decreased significantly from 13.9 +/- 0.5 mmol/l to 11.0 +/- 1.3 mmol/l (n = 18, p < 0.05) at the fourth day and to 7.6 +/- 1.0 mmol/l (n = 18) at the 14th day of 15-DSG administration. That was not significantly different from the mean glycemic level during the normoglycemic period (7.6 +/- 1.0 vs. 7.0 +/- 1.7 mmol/l, n = 18, p = NS). Isotonic sodium chloride solution injections did not reduce glycemic levels of mice in the control group. As another control, 10 streptozotocin-induced diabetic mice were given the same daily doses of 15-DSG for 14 days. 15-DSG did not decrease the blood glucose levels of diabetic mice in the control group. We further studied the effect of 15-DSG on the expression of interleukin-1beta (IL-1beta) in peritoneal exudate mononuclear cells (PEMCs) using reverse transcription-polymerase chain reaction. It was found that the mRNA of IL-1beta was undetectable in PEMCs of 15-DSG-treated diabetic mice even after those cells were stimulated by lipopolysaccharides in vitro. Administration of 15-DSG at a daily dose of 0.625 mg/kg body weight from the 22nd to the 28th day after transplantation and 7 consecutive days every 3 weeks thereafter did not prolong graft survival of i.p. microencapsulated rat islets. Our data suggest that 15-DSG has a rescue effect when A-P-A microencapsulated islets have induced cellular overgrowth that threatens the survival of the graft. It is possible that the surface overgrowth composed of macrophages is involved in the pathophysiology of late failure of A-P-A microencapsulated xenogeneic islets.

Effect of liposomes on mineralization in rat osteoblast-enriched cultures

Liposomes, artificial membranous lipid vesicles, have been used as model structures for biological calcification processes. However, there is no definite conclusion that liposomes can be like matrix vesicles for inducing bone calcification and bone-like tissue formation on primary cultured cells. To determine whether liposomes can promote bone cell growth and mineralization by inducing crystal nucleation, liposomes composed of egg phosphatidylcholine, cholesterol, and bovine brain phosphatidylserine were added to 21-day-old Sprague-Dawley fetal rat calvarial cell cultures from day 1. The aims were to observe proliferation and the phenotype of osteoblasts by measuring cell numbers and alkaline phosphatase (ALP) activity and, when added at confluence, to observe calcification. The data were analyzed with two-way ANOVA. During the 16-day culture period, cell numbers were not significantly affected by liposomes (100 mumol/L). However, ALP activity was significantly inhibited by liposomes (p < 0.05) at day 16 and thereafter. Calcified particles were detected by von Kossa's method, and were larger and more abundant (p < 0.05) in the liposomes groups than in the control from days 12-24. This response depended on liposomes dose. These findings suggest that liposomes promote calcification and accelerate the formation of bone-like tissue. Liposomes slightly reduce the expression of the osteoblast phenotype and do not affect cell growth in primary rat osteoblast-enriched cultures.

Sterically stabilized anti-idiotype immunoliposomes improve the therapeutic efficacy of doxorubicin in a murine B-cell lymphoma model

A liposome containing diverse synthetic lipid derivatives of polyethylene glycol (PEG) results in smaller distribution volume and longer circulation time in blood and, thus, may improve drug targeting. The characteristics and therapeutic efficacy of immunoliposomes with similar liposomal formulation have never been studied in lymphoma models. We have developed immunoliposomes conjugated with S5A8 monoclonal antibody, an anti-idiotype antibody to 38C13 murine B-cell lymphoma, and loaded them with doxorubicin using an ammonium sulfate gradient. Purified antibodies were covalently coupled to the termini of PEG on the surface of small unilamellar liposomes. Cell binding and internalization ability of these immunoliposomes were estimated by a fluorescence assay using a pH-sensitive fluorescent dye (HPTS). The in vitro cytotoxicity of doxorubicin encapsulated in immunoliposomes was greater for idiotype-positive 38C13 cells than for the idiotype-negative variant of this cell line. In syngeneic C3H/HeN mice, doxorubicin encapsulated in immunoliposomes exhibited a long circulation time and was more effective at prolonging survival of mice bearing 38C13 tumor than non-targeted liposomal doxorubicin or free doxorubicin plus empty immunoliposomes. Our results demonstrate the superiority of targeted therapy with these immunoliposomes and its potential in lymphoma treatment.

Temporal and spatial expression of erbB4 in ectodermal and mesenchymal cells during primary palatogenesis in noncleft and cleft strains of mice

Primary palatogenesis in mice is similar to that in humans, and spontaneous cleft lip appears to be multifactorially determined in both. Binding of a ligand to erbB4 has been shown to stimulate the receptor's protein kinase activity, which subsequently stimulates a signal-transduction cascade leading to cell growth and differentiation, and to morphogenesis during development. In this study, an immunohistochemical technique was used to investigate the temporal and spatial expression of erbB4 in the primary palate of cleft (A/WySn) and noncleft strains of mice (BALB/cBy). Positive staining of erbB4 was found in ectodermal and mesenchymal cells of facial prominences before the primary palate formation stage (day 10, hour 20) in both strains. During the primary palate formation stage (day 11, hour 20), positive staining of erbB4 was found in the ectodermal and mesenchymal cells of the facial prominences of the noncleft strain, but not in those of the cleft strain. These results suggest erbB4 expression may be associated with normal primary palatogenesis of mice and, conversely, cleft lip may be associated with a deficiency of erbB4 expression during primary palate formation in mice.

Obstetrical hysterectomy and placenta previa/accreta: three bladder injury case reports

Pregnancies complicated with placenta previa and a history of cesarean section are well known to be at increased risk for placenta accreta. Bladder injury is occasionally encountered in these patients during operation. From January 1992 to December 1995, 25 obstetrical hysterectomy were performed at Chang Gung Memorial Hospital, Linkou Medical Center. Of these 25 patients three had bladder injury. Ultrasonography is a unique way to screen and detect prenatally the abnormal placentation and intraplacental lacunae. Color Doppler ultrasonic scanning further discloses that the lacunae are mainly venous spaces. Elevated mid-trimester maternal serum x-fetoprotein (MSAFP) frequently leads to a suspicion of the abnormal placentation, and magnetic resonance imaging (MRI) can clearly identify the placenta accreta/increta. Uncontrollable bleeding frequently occurs in these patients during cesarean section, warranting emergency hysterectomy. Emergency obstetrical hysterectomy should be decided upon and performed by an experienced obstetrician. Massive hemorrhage and bladder injury are the major complications encountered in such operations. We review the literature and propose a protocol of management. As the incidence of cesarean section continues to rise world-wide, the problem of placenta previa/accreta is likely to become more common. Obstetricians should be ready to face the late sequelae of today's decision for cesarean section.

Toxin production of Alexandrium minutum (Dinophyceae) from the Bay of Plenty, New Zealand

Paralytic shellfish toxins of two clonal cultures of Alexandrium minutum isolated during the 1993 toxic shellfish events in the Bay of Plenty, New Zealand, were analyzed using high-performance liquid chromatography. Toxin composition profiles of both cultures showed neosaxitoxin (> 65 mole%) as the principal toxin, with saxitoxin and gonyautoxins (GTX1-4) as minor components. Neither C-toxins (C1-4) nor GTX5-6 were detectable in the two isolates. Bay of Plenty isolates of A. minutum have a unique toxin profile not found in any other isolates of this species that have been characterized. This weakens the hypothesis that A. minutum was recently introduced to New Zealand waters by ballast water or other long-distance transport mechanisms, and argues instead that the species was endemic to the area, but not noticed in the past. The average toxicity of the cultures was 8.8 and 11.0 pg saxitoxin equiv. cell-1 with acetic acid or HCl extraction, respectively. These are at the high end of the range of toxicity reported for A. minutum strains from around the world, and on a cell volume basis are comparable to the most toxic strains of the Alexandrium tamarense group. The toxin profile of A. minutum most closely matches that of mussels and to a lesser degree tuatua harvested from the Bay during the 1993 outbreak, but is quite different from the profile measured in scallops and pipi. Plausible mechanisms for bioconversion of the ingested algal toxins within the latter two shellfish species can be proposed, but it seems more likely that either other strains of A. minutum or other saxitoxin-producing dinoflagellates were ingested by those shellfish. This study established that A. minutum from the Bay of Plenty contains saxitoxins, has a unique toxin composition compared to all other isolates of this species, and was responsible for at least part of the PSP toxicity measured in shellfish during the 1993 outbreak.

Color Doppler energy in prenatal diagnosis of meconium peritonitis: a case report

Meconium peritonitis is an uncommon chemical peritonitis of a fetus resulting from antenatal bowel perforation. We reported a case of meconium peritonitis with pseudocystic formation diagnosed by color Doppler energy (CDE) at 34 gestational weeks. An echogenic substance inside a fetal abdominal mass was detected using ultrasound. By conventional color Doppler, there was minimal blood flow in the cystic wall or septums of the mass. Using CDE, bowel hyperperistalsis was observed in multiple small bowel loops and the region of intestinal loops into the mass was easily detected. Therefore, the angle independent nature of CDE will play a significant role in the early and accurate diagnosis of meconium peritonitis before birth.

Life table analysis of pregnancy rates in women with moderate or severe endometriosis comparing danazol therapy after carbon dioxide laser laparoscopy plus electrocoagulation or laparotomy plus electrocoagulation versus danazol therapy only

STUDY OBJECTIVE

To assess the effectiveness, in terms of pregnancy rates, of isotopic 13CO2 laser laparoscopy versus traditional laparoscopy or laparotomy in the treatment of infertile women with moderate or severe endometriosis.

DESIGN

Prospective 5-year study.

SETTING

Medical school-affiliated hospital.

PATIENTS

Three hundred nine infertile women with moderate to severe endometriosis.

INTERVENTIONS

The patients were treated with one of four options: operative laparoscopy with the 13carbon dioxide (13CO2) laser vaporization and/or resection, operative laparoscopy with simple electrocoagulation and sharp dissection, laparotomy with electrocoagulation and sharp dissection, and medical treatment with danazol. Estimated cumulative pregnancy rates using life table analyses were indicators of treatment of success and compared among treatments. A subgroup of 192 women considered to have endometriosis as the only infertility factor was also evaluated.

MEASUREMENTS AND MAIN RESULTS

Pregnancy rates in the laparoscopy group were equal to or higher than those of the laparotomy group, for both the entire population and the endometriosis-only subset. When the CO2 laser was used as an adjuvant option, the rates were better, especially in patients with advanced disease and with endometriosis as the only infertility factor.

CONCLUSION

In women with endometriosis as the only infertility factor, laparoscopic surgery with the 13CO2 laser was more effective than nonlaser treatment.

Efficacy of isotopic 13CO2 laser laparoscopic evaporation in the treatment of infertile patients with minimal and mild endometriosis: a life table cumulative pregnancy rates study

STUDY OBJECTIVE

To assess the efficacy of 13CO2 laser laparoscopy in treating infertile women with minimal to mild endometriosis according the American Fertility Society classification in terms of pregnancy rates.

DESIGN

Prospective study.

SETTING

Medical school-affiliated hospital.

PATIENTS

One hundred seventy-six women whose infertility was associated with minimal or mild endometriosis diagnosed by laparoscopy.

INTERVENTIONS

The patients were treated with one of four methods: 49 underwent operative laparoscopy with newly developed 13CO2 laser vaporization and/or resection; 45 were treated by operative laparoscopy with simple monopolar electrocoagulation; 43 who had undergone only diagnostic laparoscopy did not receive any treatment; and 39 received danazol 800 mg/day for 3 months after diagnostic laparoscopy.

MEASUREMENTS AND MAIN RESULTS

Estimated cumulative pregnancy rates using life table analyses were indicators of treatment of success and compared among the treatments. A subgroup of 111 patients considered to have endometriosis as the only major infertility factor were also evaluated and compared among treatment options. Pregnancy rates in the CO2 laser laparoscopy group were significantly higher than in the other three groups and in endometriosis-only subset.

CONCLUSIONS

Advanced laparoscopic surgery with the CO2 laser can be more efficient than other modalities in treating infertile women with minimal to mild endometriosis in terms of pregnancy rates. It appears that in experienced hands, laser laparoscopy has more favorable results than the other treatments.

The importance of determination of jaw position in orthodontic diagnosis and treatment planning for adult patients

The basic data needed for orthodontic diagnosis and treatment planning include color prints of soft tissue facial profile, intraoral dental arches, and occlusion; cephalometric and panoramic radiographs; and dental casts. Hand-wrist and TMJ radiographs are also necessary in some circumstances. If orthodontic diagnosis and treatment plans are made only from the dental alignments and occlusion from the static or hand-assembled dental casts, the diagnosis and treatment planning made may be wrong in some cases. Clinically, it is necessary to find the centric relation of the lower jaw and to transfer the jaw relationship to the articulator. Correct diagnosis and orthodontic treatment planning may then be made from the findings of the occlusal relationship from the articulator accompanied with the information on skeletal age and craniofacial characteristics from the hand-wrist and cephalometric radiographs. Four clinical cases have been presented to demonstrate the importance of determination of jaw position in orthodontic diagnosis and treatment planning in adult patients.

The effects of Vero cell co-culture on human zygotes resulting from in vitro fertilization and oocytes following subzonal insemination

A variety of co-culture systems have been devised to enhance the human embryo development in vitro. Vero cells were selected because they can be highly controlled and are easy to handle. To evaluate the embryotrophic effects of Vero cell monolayers, when they were co-cultured with human in vitro fertilized zygotes or subzonal inseminated oocytes. Total 1695 two-pronuclear embryos resulting from in vitro fertilization were cultured with Vero cells or medium alone for 24 hours. Similarly, sixty-six two-pronuclear embryos resulted from subzonal insertion of sperm (SUZI) with co-culture starting immediately following SUZI were compared with fifty-two two-pronuclear embryos resulted from SUZI, without co-culture. The numbers of blastomere and morphology of embryos were compared between the co-culture group and control group using student's t-test. Cell numbers in each embryo were greater in the IVF/co-culture group than in the control group (4.01 +/- 1.32 vs. 3.86 +/- 1.45, p < 0.05). The rates of poor quality embryo with major fragmentation were lower in the co-culture group than in the control group(11.5% vs. 19.9%, p < 0.001, for IVF embryos; 9% vs. 27%, p < 0.005, for SUZI oocytes). Co-culture SUZI oocytes on Vero cells prior to fertilization did not positively influence embryo cleavage, but improved embryo quality. We conclude that Vero cells can enhance human embryo development; however, the period for one-day or two-day co-culture is too short to provide a maximal support. Short term co-culture did not increase implantation rates. Immediate co-culture following SUZI might somewhat rescue the microinseminated oocytes. However, a longer duration of co-culture is necessary to exert the maximal effects on embryo development and implantation.

Laparoscopic Removal of a Large Leiomyoma Using Airlift Gasless Laparoscopy

Some discrepancies still exist with regard to the efficacy of laparoscopic removal of large symptomatic leiomyomas. In our experience, when performing myomectomy, airlift gasless laparoscopy has several advantages. First, a small incision can be made, through which conventional surgical instruments (endoscopic equipment is not required) are inserted and the myomectomy is efficiently performed. Second, the large excised leiomyoma can be cut into strips easily with a conventional long knife and removed through a small abdominal incision. Third, sutures can be placed easily, and the surgeon can place fingers through a small surgical wound to palpate the organ and tie the knot directly. Fourth, high-pressure irrigation and large-volume suction devices can be used without fear of decompressing the pneumoperitoneum. Finally, the potential risks of metabolic and hemodynamic instability due to carbon dioxide insufflation to establish pneumoperitoneum are avoided.

Laparoscopic myomectomy of large symptomatic leiomyoma using airlift gasless laparoscopy: a preliminary report

Despite the expanding role of laparoscopic surgery in many gynaecological fields, some discrepancies still exist regarding the efficacy of laparoscopic myomectomy in treating patients with large symptomatic leiomyoma. In this report, a better operative procedure and the results of treatment are evaluated. Patients (n = 14) presenting with infertility, menorrhagia, pressure symptoms or pelvic mass associated with a large leiomyoma were managed with laparoscopic myomectomy using airlift gasless laparoscopy. Uterine size ranged from 14 to 24 weeks gestational age and the weight of the myoma ranged from 246 to 669 g (mean 454); operative time ranged from 78 to 165 min (mean 104) and blood loss from 90 to 580 ml (mean 201). No major complication occurred during the operation or follow-up. All except one patient were discharged within 72 h of the operation and resumed normal activity within 1 week. When myomectomy is indicated, the airlift gasless laparoscopic approach appears to offer a better alternative to abdominal or pneumoperitoneum laparoscopic surgery in selected cases. Airlift gasless laparoscopy has several advantages: (i) small abdominal incisions and minimal endoscopic equipment are required; (ii) the excised leiomyomata mass can be easily cut into strips and removed through the small abdominal incision; (iii) the uterine defect can be more efficiently repaired using easily performed suture techniques; (iv) high-pressure irrigation and large-volume suction devices can be used without fear of decompressing the pneumoperitoneum; and (v) the potential risk of metabolic and haemodynamic derangements during pneumoperitoneum laparoscopy are obviated. Gasless laparoscopy also has some disadvantages. The exposure obtained with gasless laparoscopy is not as good, under some circumstances, as that achieved by pneumoperitoneum. For patients who are thin, and even those with moderate obesity, the exposure obtained with airlift mechanical suspension is adequate; however, morbidly obese patients with previous abdominal surgery with suspected pelvic adhesions can incur some problems during the operation because of a poor operative field.

Insulin-like growth factor-binding proteins produced by Vero cells, human oviductal cells and human endometrial cells, and the role of insulin-like growth factor-binding protein-3 in mouse embryo co-culture systems

Co-culturing embryos on helper cells can mimic the in-vivo environment, thereby enhancing embryo development in vitro. Insulin-like growth factors (IGF) and their binding proteins (IGFBP) also enhance embryo development. To investigate the kinds of IGFBP produced by various cell monolayers and the effects of IGFBP-3 on mouse embryo co-culture systems, 2-cell ICR mouse embryos were cultured in either human tubal fluid medium alone or in the presence of Vero cells, human oviductal cells or endometrial cells. The helper cells were analysed immunohistochemically to investigate the types of IGFBP produced by various cell monolayers. The concentrations of IGF-I and IGFBP-3 in media obtained from the culture of embryos alone, cells alone or cells plus embryos were determined by radioimmunoassays. On day 7, more blastocysts hatched in the co-culture groups (73% in the Vero cell group, 76% in the endometrial cell group and 74% in the oviductal cell group) than in the control group (43%) (P < 0.0001). The results of immunohistochemistry revealed that (i) all three cell groups produced a lot of IGFBP-1, -2 and -3, but only a little of IGFBP-4 and -5; and (ii) IGFBP-1, -2, and -3 were present in blastocysts in either the presence or absence of helper cells. The IGF-I secreted by cell monolayers or embryos was undetectable (detection limit 0.83 microg/l). The IGFBP-3 concentrations in media obtained from co-cultured embryos and cells were significantly higher than in media without embryos (median values in oviductal cell culture medium, 165 versus 127 microg/l, P = 0.04; median values in endometrial cell culture medium, 277.5 versus 183.5 microg/1, P = 0. 0002; median values in Vero cell culture medium, 219 versus 120 microg/l, P = 0.011). Although IGFBP-3 concentration in the medium that contained embryos alone was undetectable by radioimmunoassay (detection limit 1.1 microg/l), immunohistochemistry demonstrated the presence of IGFBP-3 in the embryos. Co-culture in systems in which there was an increased production of IGFBP-3 led to an improved development of mouse embryos. IGFBP can improve the binding of IGF to cell surface receptors of target tissue, and thus enhance the effect of limited IGF concentrations in promoting embryo development in a co-culture system. We conclude that Vero cells, human endometrial cells and oviductal cells produce IGFBP-1, -2, -3, -4 and -5. IGFBP-3 may play a role in embryotrophic potential by either regulating the action of IGF or directly enhancing embryo development.

Coculture of human spermatozoa with reproductive tract cell monolayers can enhance sperm functions better than coculture with Vero cell monolayers

PURPOSE

In order to develop a better system for support of human sperm function in vitro, we conducted studies to evaluate whether reproductive tract cells are better than non-reproductive tract cells as an adjunt in that regard.

METHODS

Human spermatozoa were cocultured with Vero cells, with human oviduct cells and endometrial cells, and without cells (control) for either 1, 4, or 24 hr. Sperm motility was then analyzed with a computer-aided sperm analyzer (CASA-Hamiliton Thron, HTM IVOS Motility Analyzer). Aliquots of spermatozoa incubated for 24 hr were also stained with Hoechst 33258 and FITC-PNA to evaluate the status of acrosome in live cells.

RESULTS

Significant differences (P < 0.05) between the oviduct cell and the control groups after 24 hr were evident in the curvilinear velocity (VCL) (81.4 +/- 13.4 vs 60.0 +/- 14.1 microns/sec) and amplitude of lateral head displacement (ALH) (5.2 +/- 0.6 vs 4.1 +/- 0.5 microns). The incidence of acrosome reaction of live sperm was significantly higher in the endometrial cell group than in the controls (25.4 +/- 9.9 vs 6.6 +/- 2.4%; P < 0.001).

CONCLUSIONS

Coculture with human reproductive tract cells seems to improve some functional parameters of human spermatozoa. Coincubation with such cell lines, especially oviduct cells, might be a feasible approach to optimization of human spermatozoa for assisted fertilization using subfertile or frozen-thawed samples. We think coincubating human spermatozoa with a human reproductive tract cell line, especially oviduct cells, might be a feasible approach in preparing human spermatozoa for assisted fertilizatioin in subfertile and frozen-thawed semen samples.

Results of modified laparoscopically assisted neovaginoplasty in 18 patients with congenital absence of vagina

Construction of a neovagina using pelvic peritoneum via a laparoscopically assisted approach was used in 18 patients with congenital absence of the vagina. A better operative procedure is reported, which was modified from our preliminary technique, and the results of treatment are evaluated. Pelvic peritoneum was used for construction of a vagina, replacing a laparotomy by a minimally invasive laparoscopic approach. During follow-up, the advantages of our procedures are: (i) minimal likelihood of 'poor take' or later contraction because an autograft peritoneal epithelial line is used; (ii) minimal short and long term care is required; (iii) the technique is simple in experienced hands and has all the well-recognized benefits of minimal invasive surgery; (iv) the average length of neovagina is adequate and patency and depth can be maintained with minimal dilatation; (v) the neovagina, with epithelial lining resembling that of a normal vagina, facilitates comfortable sexual intercourse; (vi) the procedure is unaccompanied by dyspareunia or scarring, which are frequently associated with other techniques; (vii) less emotional stress and better cosmetic and economic benefits are noted.

Laparoscopic repair of bowel herniation through previous cannula insertion sites

Operative laparoscopy frequently requires large cannulas below or above the umbilicus, which may result in unusual complications such as small bowel herniation through these insertion sites. Three women experienced small bowel herniation through cannula incision sites, either extraumbilically or paraumbilically, after major laparoscopic surgery. Two patients who had undergone laparoscopic myomectomy developed small bowel herniation through the 12-mm extraumbilical cannula site on postoperative days 7 and 8, respectively. In the first woman, the nontender, palpable, and reducible herniation healed spontaneously, with no episode of herniation during follow-up. The second patient required laparoscopic reduction of the herniated loop and repair of the fascial defect. The last woman had undergone laparoscopic-assisted vaginal hysterectomy and developed small bowel herniation through an unrecognized fascial defect paraumbilically 3 days postoperatively. Intended repair by laparoscopy was changed to laparotomy due to extensive and incarcerated bowel herniation.

Extraumbilical insertion of the operative laparoscope in patients with extensive intraabdominal adhesions

In 12 patients who had known or suspected intraabdominal adhesions, we evaluated the benefit of using Palmer's point for inserting the Veress needle and primary cannula during laparoscopic adhesiolysis to prevent direct intestinal injury. After inserting the laparoscope through this point, four women were found to have extreme intestinal adhesions around the umbilical area, and intestinal or severe omental injury might occur if the cannulas were inserted directly through the umbilical fossa. The other eight patients had omentum, partial to severe, adherent to the anterior abdominal wall. No complication occurred during insertion of the Veress needle and primary cannula through Palmer's point. Nine patients had successful laparoscopic adhesiolysis and were discharged within 2 days. In the other three women the procedure was converted to laparotomy because of extensive intestinal adhesions (2 patients) and small bowel injury during laparoscopic adhesiolysis (1). Palmer's point can be considered a safe and good alternative site for inserting the Veress needle and primary cannula to lyse dense intestinal and extensive omental adhesions. This technique should provide the surgeon with wider visual angel and surgical field, thus making adhesiolysis much easier to perform.

Combined laparoscopic hysterectomy and cholecystectomy--a case report

We present the first recorded case which received a combined laparoscopic hysterectomy, right salpingo-oophorectomy and cholecystectomy during one anesthetic period in Taiwan. This procedure was done to treat the coexisting benign lesions of the uterus, ovary, and the gall bladder. Postoperative pathological diagnoses was myoma, an ovarian hemorrhagic corpus leutum cyst, cholelithiasis, and cholecystitis. Estimated blood loss was less than 150 ml for the combined procedure. With the total operation time being 135 minutes. The patient recovered soon and could take a regular diet and walk without assistance 20 hours after operation. She discharged 4 days later and returned to work 5 days after discharge. We think for well trained laparoscopists, a cross-specialty cooperation between a gynecologist and a general surgeon to treat coexisting lesions of the uterus and the gall bladder is a safe, feasible, and beneficial procedure.

Use of Palmer's Point for Insertion of the Operative Laparoscope in Patients with Severe Pelvic Adhesions: Experience of Seventeen Cases

Seventeen patients who had known or suspected intra-abdominal adhesions underwent laparoscopic surgery with the use of Palmer's Point for insertion of the operative laparoscope. Five of them were found to have extensive periumbilical adhesions. Intestinal or omental injury can occur if the trocar is inserted directly through the umbilical fossa. Though the incidence of direct trauma is reportedly low, there were still mild to moderate omental adhesions to the anterior abdominal wall, as we expected, in the remaining 12 patients. Possible inadequate aspiration and irrigation during laparoscopic removal of a dermoid cyst in one woman had resulted in severe postsurgical intraabdominal adhesions. More than two 10 mm incisions were used in our patients for insertion of the laparoscope interchangeablely to facilitate the procedure of laparoscopic adhesiolysis. The operative field can be expanded greatly. Fourteen patients completed the laparoscopic surgery, and the other 3 had alternative procedures eventually. No complications occurred during the laparoscopic procedure. The postoperative courses were uneventful in all 17 patients. Our experience suggests that Palmer's Point is a good alternative for insertion of the Veress needle and laparoscope in patients with previous laparotomies and suspected severe pelvic adhesions.

Treatment of malignant germ cell tumors of the ovary

Thirty-five patients with ovarian germ cell malignancies presenting from 1982 to 1992 were studied. The pathologic diagnoses were immature teratoma in 11 patients, endodermal sinus tumor in eight, dysgerminoma in 12, and mixed germ cell tumor in four. The median age at presentation was 20 years. Postoperative multiple-agent chemotherapy was given to 28 patients. Five out of 35 (14%) patients died of malignancy, three with endodermal sinus tumors with stage Ia, Ic, and IIIc, respectively, one with stage IIIc dysgerminoma, and one with stage IIIc mixed germ cell tumor. The other 30 patients were alive without evidence of disease from 14 to 124 months, with a median follow-up of 52 months. All eleven patients with immature teratoma were alive with no evidence of disease at 20 to 104 months of follow-up. Four patients with stage I, grade 1 immature teratoma were successfully treated with surgery alone. The other seven patients were treated with adjuvant chemotherapy and were disease-free. One patient with stage IIIc dysgerminoma was treated with surgery and radiotherapy but died of disease. The other eleven patients were safely treated with surgery and adjuvant chemotherapy with vincristine, actinomycin-D and cyclophosphamide (VAC) or platinum-based chemotherapy. For the more virulent tumors such as endodermal sinus tumor and mixed germ cell tumor, platinum-based chemotherapy should be used exclusively in view of the high failure rate of the VAC regimen. Preservation of fertility for young patients with malignant ovarian germ cell tumors is possible in the early stages of disease and in selected cases of advanced disease.

Expression of a human cDNA encoding a protein containing GAR synthetase, AIR synthetase, and GAR transformylase corrects the defects in mutant Chinese hamster ovary cells lacking these activities

The isolation of a human cDNA encoding the multifunctional protein containing GAR synthetase, AIR synthetase, and GAR transformylase by functional complementation of purine auxotrophy in yeast has been reported. Chinese hamster ovary (CHO) cell mutant purine auxotrophs deficient in GAR synthetase (Ade-C) or AIR synthetase plus GAR transformylase (Ade-G) activities were transfected with this human GART cDNA subcloned into a mammalian expression vector. This restored 49-140% of the activities of GAR synthetase, AIR synthetase, and GAR transformylase in transfected cells when compared to wild-type CHO K1 parental cells. Study of one stably expressing transfectant, AdeC2, revealed that the human GART cDNA was incorporated into the CHO genome. The enzyme activities appear to be associated with an expressed protein of 110 kDa, very similar to that of purified human GART trifunctional enzyme. The Ade-C mutant shows reduced amounts of GART mRNA compared to CHO K1 and a protein of apparently reduced size, results consistent with the purine requirement and enzyme deficiency observed in the mutant. These experiments provide definitive evidence that the human GART cDNA encodes and can direct the production of active human GART trifunctional protein in mammalian cells. They also provide important evidence that the Ade-C and Ade-G mutants of CHO cells are defective in this gene.

Mutations in the GTP-binding site of GS alpha alter stimulation of adenylyl cyclase

Mutational replacements of specific residues in the GTP-binding pocket of the 21-kDa ras proteins (p21ras) reduce their GTPase activity. To test the possibility that the cognate regions of G protein alpha chains participate in GTP binding and hydrolysis, we compared signaling functions of normal and mutated alpha chains (termed alpha s) of Gs, the stimulatory regulator of adenylyl cyclase. alpha s chains were expressed in an alpha s-deficient S49 mouse lymphoma cell line, cyc-. alpha s in which leucine replaces glutamine 227 (corresponding to glutamine 61 of p21ras) constitutively activates adenylyl cyclase and reduces the kcat for GTP hydrolysis more than 100-fold. There is a smaller reduction in GTPase activity in another mutant in which valine replaces glycine 49 (corresponding to glycine 12 of p21ras). This mutant alpha s is a poor activator of adenylyl cyclase. Moreover, the glycine 49 protein, unlike normal alpha s, is not protected against tryptic cleavage by hydrolysis resistant GTP analogs; this finding suggests impairment of the mutant protein's ability to attain the active (GTP-bound) conformation. We conclude that alpha s residues near glutamine 227 and glycine 49 participate in binding and hydrolysis of GTP, although the GTP binding regions of alpha s and p21ras are not identical.

Cholera toxin induces cAMP-independent degradation of Gs

Cholera toxin stimulates adenylyl cyclase by catalyzing ADP-ribosylation of the alpha chain (alpha s) of Gs, a guanine nucleotide binding regulatory protein. In a rat pituitary cell line, GH3, the toxin-induced increase in GTP-dependent adenylyl cyclase activity is maximal at 1 h; adenylyl cyclase remains elevated for at least 32 h. Surprisingly, cholera toxin also induces a 74-95% decrease in the amount of immunoreactive alpha s in the same cells, as assessed on immunoblots probed with either of two antisera directed against separate alpha s peptide sequences. The decrease in immunoreactive alpha s, which begins after 1 h of toxin treatment and is complete by 8 h, is accompanied by a comparable decrease in the amount of biochemically active alpha s, as assessed by its ability to complement the biochemical defect of alpha s-deficient S49 cyc- membranes. Cholera toxin induces similar decreases in alpha s in wild type S49 lymphoma cells, in S49 kin- mutants, which lack cAMP-dependent protein kinase, and in S49 H21 a mutants, in which alpha s is unable to assume an active conformation upon binding GTP. The toxin-induced decrease in alpha s is somewhat temperature-dependent, but is not blocked by agents that increase lysosomal pH or by colchicine, which promotes breakdown of microtubules. alpha s in detergent-solubilized GH3 membranes is susceptible to proteolysis by an endogenous protease; this susceptibility is markedly increased in membranes from cells previously exposed to cholera toxin for 1 h. Taken together, these results suggest that cholera toxin-induced covalent modification of alpha s marks the protein for accelerated degradation. In addition, the persistence of elevated GTP-dependent adenylyl cyclase activity despite loss of a substantial fraction of alpha s suggests that the amount of alpha s membranes is greater than the amount necessary for maximal activation of cAMP synthesis by cholera toxin.

Differentiation of human neuroblastoma cells: marked potentiation of prostaglandin E-stimulated accumulation of cyclic AMP by retinoic acid

Neuroblastoma cells in culture contain low levels of cyclic AMP, a second messenger which plays a major role in neuronal maturation. In this study, human neuroblastoma cells, SK-N-SH-SY5Y, were induced to differentiate by treatment with either nerve growth factor (50 ng/ml), retinoic acid (10 microM), dibutyryl cyclic AMP (1 mM), or 12-O-tetradecanoylphorbol-13-acetate (0.1 microM), and the ability of several neurotransmitters or hormones to stimulate adenylyl cyclase was tested. Although all four differentiation factors caused morphological changes towards a neuronal phenotype, only retinoic acid dramatically enhanced cyclic AMP accumulation, specifically upon stimulation with prostaglandin E1 (PGE1). PGE2 was also active, but less potent, than PGE1, whereas the other cyclic AMP-stimulating agents tested were largely unaffected. Further, the rapid desensitization of the PGE1-cyclic AMP response observed in control cells after 20 min of PGE1 exposure did not occur in retinoic acid-treated cells, and the EC50 values for PGE1 were reduced from approximately 240 to 14 nM after retinoic acid treatment. The increased sensitivity to PGE was associated with an increase of high-affinity PGE1 binding sites, whereas the Gs coupling proteins and adenylyl cyclase were not measurably affected. A similar enhancement of the PGE1-cyclic AMP response by retinoic acid was also observed in two additional human neuroblastoma cell lines tested, Kelly and IMR-32, suggesting that up-regulation of the prostaglandin response by retinoic acid is common among neuroblastoma cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Chronic ethanol causes heterologous desensitization of receptors by reducing alpha s messenger RNA

One of the biochemical results of ethanol exposure is a change in the amount of the intracellular second messenger cyclic AMP (cAMP) produced in response to receptor stimulation. In general, acute ethanol exposure increases the amount of cAMP produced on stimulation of receptors coupled to the enzyme adenylyl cyclase via the GTP-binding protein Gs, whereas chronic ethanol exposure has the opposite effect (results for receptors coupled via Gi have been more variable). We previously reported that adaptation to continuous ethanol exposure reduces receptor-stimulated cAMP production by 25-35% in a neuroblastoma cell line (NG108-15), and an even greater reduction of 75% was observed in lymphocytes taken from actively-drinking alcoholics. This reduction in receptor-stimulated cAMP levels was recently confirmed in platelets from alcoholics. None of these studies, however, determined whether more than one receptor coupled to adenylyl cyclase activity was affected in the same cell. Here we report that chronic ethanol exposure causes desensitization of heterologous receptors coupled to Gs as cAMP production mediated by prostaglandin E1 as well as by adenosine is reduced by approximately 30% in NG108-15 cells. We show that, after chronic ethanol exposure, the activity of the alpha subunit of Gs is decreased by 29%, the amount of alpha s protein is decreased by 38.5%, and alpha s messenger RNA is decreased by 30%. Thus, cellular adaptation to ethanol involves a reduction in alpha s mRNA and, as a consequence, reduced cAMP production by heterologous receptors coupled to Gs. Such changes in cAMP production may account for the tolerance and physical dependence on ethanol in alcoholism.

Dexamethasone increases adenylyl cyclase activity and expression of the alpha-subunit of Gs in GH3 cells

Glucocorticoids regulate responsiveness of many different cells and tissues to hormones that act by stimulating adenylyl cyclase. In a rat pituitary cell line, GH3, exposure to dexamethasone (150 mM for 72 h) doubled the specific activity of adenylyl cyclase in membrane extracts, whether the enzyme was stimulated by guanine nucleotides, vasoactive intestinal peptide, or forskolin. Dexamethasone treatment of GH3 cells also caused a 5-fold increase in RNA encoding the alpha-chain of Gs (alpha s) as well as a 2-fold increase in membrane-bound alpha s-polypeptide, measured by either of two assays: 1) Biochemical complementation of the alpha s deficiency of S49 lymphoma cyc- membranes in vitro; 2) Cholera toxin-catalyzed ADP ribosylation of 45- and 52-kilodalton alpha s-polypeptides. These observations suggest that glucocorticoid-induced enhancement of adenylyl cyclase activity in GH3 cells is mediated, at least in part, by increased expression of alpha s.

Inhibitory and stimulatory G proteins of adenylate cyclase: cDNA and amino acid sequences of the alpha chains

The G protein family of signal transducers includes five heterotrimers, which are most clearly distinguished by their different alpha chains. The family includes Gs and Gi, the stimulatory and inhibitory GTP-binding regulators of adenylate cyclase; Go, a protein of unknown function abundant in brain; and transducin 1 and transducin 2, proteins involved in retinal phototransduction. Using a bovine alpha t1 cDNA as a hybridization probe, we have isolated mouse cDNAs that encode alpha chains of two G proteins. One encodes a polypeptide of 377 amino acids (Mr 43,856), identified as alpha s because it specifically fails to hybridize with any transcript in an alpha s-deficient S49 mouse lymphoma mutant, cyc-; the other encodes a polypeptide of 355 amino acids (Mr 40,482), presumed to be alpha i. These alpha chains and those of the retinal transducins exhibit impressive sequence homology. Of the four, alpha t1 and alpha t2 are most alike (81% identical amino acid residues), whereas the presumptive alpha i is more similar than alpha s to alpha t1 (63% vs. 38% identical residues). Sequence homologies with p21ras and elongation factor Tu identify regions of the alpha chains that form the site for GTP binding and hydrolysis. Further comparison of the alpha-chain sequences suggests additional regions that may contribute to interactions with beta gamma subunits and the receptor and effector components of different signal transduction systems.

Pertussis toxin inhibition of chemotactic factor-induced calcium mobilization and function in human polymorphonuclear leukocytes

Chemotactic factors stimulate a rapid increase in the cytosolic concentration of intracellular calcium ions ([Ca2+]in) in human polymorphonuclear leukocytes (PMNL), which may be an event that is critical to the expression of chemotaxis and other PMNL functions. Treatment of PMNL with pertussis toxin catalyzes ADP-ribosylation of a protein similar or identical to the inhibiting regulatory protein of adenylate cyclase, Gi, and suppresses the increase in [Ca2+]in elicited by leukotriene B4(LTB4) and formyl-methionyl-leucyl-phenylalanine. Chemotactic migration and lysosomal enzyme release elicited by chemotactic factors were inhibited by pertussis toxin with a concentration-dependence similar to that for inhibition of the increase in [Ca2+]in, without an effect on lysosomal enzyme release induced by the ionophore A23187 and phorbol myristate acetate. Activated pertussis toxin catalyzed the [32P]ADP-ribosylation of a 41 kD protein in homogenates of PMNL. The extent of [32P]ADP-ribosylation of this protein was reduced 59% by pretreatment of intact PMNL with pertussis toxin. Pertussis toxin selectively decreased the number of high-affinity receptors for LTB4 on PMNL by 60% without altering the number or binding properties of the low-affinity subset of receptors. Pertussis toxin modification of a membrane protein of PMNL analogous to Gi thus simultaneously alters chemotactic receptors and attenuates the changes in cytosolic calcium concentration and PMNL function caused by chemotactic factors.

Effects of Some Environmental Factors on Growth Characteristics of Candida utilis on Peat Hydrolysates

Samples of peat from Pine Island and Brookston bogs in Minnesota were hydrolyzed with various concentrations of HCl or H 2 SO 4 solutions, before or after debituminization (an extraction process used to remove waxy materials, bitumens, from peat), to produce peak hydrolysates as growth substrates for Candida utilis. Hydrolysates were neutralized with concentrated NaOH solution to pH 3.5, 4.5, 5.0, 5.5, 6.0, and 7.0. The precipitated humates were removed by filtration. The resulting peat hydrolysates were amended with reagent-grade K 2 HPO 4 , K 2 SO 4 , and MgSO 4 , 200, 100, and 50 mg per liter of peat hydrolysate, respectively. The debituminized peat produced more total nitrogen (TN) and reducing substances (RS) than the nondebituminized peat. Peat hydrolysates produced by HCl solutions contained slightly higher RS and TN than those produced by H 2 SO 4 solutions; however, the latter were better growth substrates than the former. The yield coefficients in both H 2 SO 4 and HCl hydrolysates initially decreased at 12 to 24 h and then increased gradually over the remaining incubation period (24 to 96 h). As TN and RS were increased, an increase in cell density, biomass, and productivity was observed. In contrast, a decrease in specific growth rate occurred as the RS and TN were increased. The generation time of C. utilis was affected by the concentrations of RS and TN. A peak substrate yield coefficient was found at pH 5.0 in HCl hydrolysates and at pH 6.0 to 6.5 in H 2 SO 4 hydrolysates. Good linear correlation coefficients were found between RS and biomass of C. utilis. The coefficients of correlation increased as the TN level in hydrolysates was increased.

Protein kinases derived from the conditioned media of human peripheral blood mononuclear cells

Two classes of cyclic nucleotide-independent protein kinase from the conditioned media of human peripheral blood mononuclear cells were detected. The first one was specific for histone, and was not retained by the remazol blue-agarose column. The second one was specific for casein and phosvitin, and was retained by the remazol blue-agarose column. Histone kinase activity was elevated in Con A-conditioned media. These peripheral blood mononuclear cells were subsequently fractionated into adherent and nonadherent cell populations. It was clear that histone kinase was secreted by adherent cells while casein and phosvitin kinases were secreted by nonadherent cells.