Calcitonin receptor gene polymorphism: a possible genetic marker for patients with calcium oxalate stones

OBJECTIVES

The formation of urinary stones is hypothesized to be associated with calcitonin receptors. The most commonly seen polymorphism is C/T at the 1377th nucleotide. Hence, these polymorphisms are being used as a genetic marker in the search for the cause of urolithiasis.

METHODS

A normal control group of 105 healthy people and 102 patients with recurrent calcium oxalate stones were examined. The polymorphism was detected following a polymerase chain reaction-based and restriction analysis by AluI. An uncuttable length is 228 bp (CC) whereas two fragments of 120 and 108 bp are shown as cuttable lengths (TT).

RESULTS

The results revealed significant differences between the normal individuals and the stone patients (p<0.01). The distribution of leucine (cuttable) homozygote in the stone group (2.0%) was higher than in the control group (0.0%). The odds ratio for the leucine allele of the calcitonin receptor gene in calcium oxalate stone disease is 5.634 (95% CI: 2.286--13.885).

CONCLUSIONS

Results show that the polymorphism in the calcitonin receptor gene could be a genetic marker for urinary stone disease and therefore it is worthwhile pursuing further studies of the leucine allele of calcitonin receptor gene due to it is strongly correlated with stone disease.

Synthesis and DNA nicking studies of a novel cyclic peptide: cyclo[Lys-Trp-Lys-Ahx-]

Two novel cyclic tetrapeptides: cyclo[Lys-Tyr-Lys-Ahx-] 7a and cyclo[Lys-Trp-Lys-Ahx-] 7b were synthesized by coupling protected amino acid in solution and the subsequent cyclization effected by the pentafluorophenyl ester method as described in previous papers. These cyclic peptides were designed and synthesized to study their interaction with DNA, based on previous reports that linear peptides Lys-Tyr-Lys and Lys-Trp-Lys could bind to various forms of DNA and cleaved supercoiled DNA at apurinic sites. Ethidium bromide displacement assay showed that the apparent DNA binding constant of linear Lys-Tyr-Lys and cyclic peptide 7a are far below 1 x 10(3) M(-1), whereas those of cyclic peptide 7b and linear Lys-Trp-Lys are 1.9 x 10(4) M(-1) and 9.5 x 10(3) M(-1), respectively. Kinetic studies using agarose gel electrophoresis showed that cyclic peptide 7b and Lys-Trp-Lys possessed DNA nicking activity on natural supercoiled phi X174 DNA with nicking rate of 50.7 and 75.6 pM min(-1) at 65 degrees C, respectively, whereas cyclic peptide 7a and linear Lys-Tyr-Lys were devoid of the corresponding activity. The DNA nicking rate increased significantly with increase in reaction temperature. At reaction temperatures lower than 65 degrees C, the DNA nicking rate of cyclic peptide 7b exceeded that of linear Lys-Trp-Lys. The addition of 1 microM ferrous ion did not give significant enhancement effect on the DNA nicking rate by the peptides. UV irradiation gave a marked rate enhancement on the DNA nicking rate of linear Lys-Trp-Lys and a moderate enhancement on the DNA nicking rate of cyclic peptide 7b.

A new "sandwich" method of combined endoscopic variceal ligation and sclerotherapy versus ligation alone in the treatment of esophageal variceal bleeding: a randomized trial

BACKGROUND

Variceal ligation is the optimum endoscopic method for treating esophageal variceal bleeding. However, both early and multiple recurrences of esophageal varices frequently follow ligation. The aim of this randomized study was to determine whether a new, combined endoscopic "sandwich" method (i.e., ligation-sclerotherapy-ligation) could achieve better results than ligation alone.

METHODS

Ninety-four patients with cirrhosis and acute or recent esophageal variceal bleeding were randomized to undergo either the "sandwich" method or ligation alone (47 patients in each group).

RESULTS

The sclerosant was retained in the varices for more than 30 minutes in 7 of 8 patients undergoing the "sandwich" method plus radiographic contrast medium. Active bleeding was controlled with this new method (9/9) as efficiently as ligation (12/12). The rate of recurrent bleeding was similar for both methods. Multivariate analysis showed the necessity for the use of antibiotics (odds ratio 3.95: 95% CI [1.60, 9.76]) to be an independent factor for recurrent bleeding. Two patients in the "sandwich" group developed strictures, but the frequency of other complications did not differ between the 2 groups. Kaplan-Meier analysis showed the cumulative probability of variceal recurrence was lower with the "sandwich" method (p = 0.0391). The survival rate and causes of death were similar in both groups.

CONCLUSIONS

The "sandwich" method leads to longer retention of sclerosant in varices. This method is superior to ligation alone in terms of lower variceal recurrence rate and comparable to ligation with respect to hemostasis. However, it is unknown whether the lower recurrence rate of varices will persist long-term.

AM-404 elevates renal intracellular Ca(2+), questioning its selectivity as a pharmacological tool for investigating the anandamide transporter

The effect of N-(4-hydroxyphenyl)-arachidonamide (AM-404), a drug commonly used to inhibit the anandamide transporter, on intracellular free Ca(2+) levels ([Ca(2+)](i)) was studied in Madin Darby canine kidney (MDCK) cells. [Ca(2+)](i) was measured using fura-2 as a Ca(2+) indicator. Between 2 and 40 microM, AM-404 increased [Ca(2+)](i) in a concentration-dependent fashion with an EC(50) value of 20 microM. Removal of extracellular Ca(2+) abolished the [Ca(2+)](i) signals. The [Ca(2+)](i) increase was nearly abrogated by 10 microM La(3+), but was insensitive to 50 microM Ni(2+) and 10 microM of nifedipine, nimodipine, nicardipine, and verapamil. At a concentration that did not increase [Ca(2+)](i), AM-404 (1 microM) did not alter the [Ca(2+)](i) increases induced by 10 microM ATP and 1 microM bradykinin. AM-404 (5 microM) also increased [Ca(2+)](i) in Chang liver cells, PC3 human prostate cancer cells, BFTC human bladder cancer cells, and MG63 human osteoblast-like cells. Together, this study shows for the first time that AM-404 at concentrations commonly used to inhibit the anandamide transporter in various systems induced an increase in [Ca(2+)](i) in different cell types. The [Ca(2+)](i) increase was solely due to extracellular Ca(2+) influx. Thus caution must be exercised in using AM-404 as a selective inhibitor of the anandamide transporter.

Repression of AIM-1 kinase mRNA as part of a program of genes regulated by Mpl ligand

Megakaryocytes give rise to platelets that are essential for thrombosis and hemostasis. During development, megakaryocytes undergo an endomitotic cell cycle by which they skip late anaphase and cytokinesis to yield high ploidy cells. This process is regulated by the c-Mpl receptor ligand. In the current study we used differential display PCR as well as degenerate cloning of kinases to identify part of the program of genes regulated during Mpl ligand-induced differentiation. Several of the induced genes were identified as encoding metabolic proteins as carnitine palmitolytransferase, while other altered genes were identified as encoding kinases. Of these, AIM-1 kinase mRNA was severely downregulated by Mpl ligand at the onset of polyploidy in megakaryocytes. This effect was not related to message stability, but rather to a change in transcriptional rate. These data point to the potential importance of the transcriptional regulation of the AIM-1 gene for promoting megakaryocyte polyploidization.

Arginine form of p21 gene codon 31 is less prominent in patients with calcium oxalate stone

The formation of urinary stones is associated with cell death in response to various injuries. P21 (WAF1/CIP1) is a downstream protein of P53 and can arrest the cell cycle at G1/S with resulting cell death. We aimed to investigate the polymorphism of p2 gene codon 31 as the genetic marker in searching for the association of urolithiasis. One hundred and nineteen healthy controls and 95 patients with calcium oxalate stone were examined in this study. The polymorphism was seen from the result of polymerase chain reaction-based restriction analysis. The result revealed significant differences between normal individuals and stone patients (P < 0.05) and the distribution of arginine homozygote in the control group (31.9%) was higher than in the patient group (16.8%). It is concluded that polymorphisms of p21 codon 31 can be a genetic marker for urinary stone disease. Individuals possessing arginine form of p21 codon 31 have less risk of developing calcium stone disease.

The reappraisal of nephrocalcin--its role in the inhibition of calcium oxalate crystal growth and interaction with divalent metal ions

Nephrocalcin (NC) is a potent crystal growth inhibitor of calcium oxalate monohydrate. However, the sequence is undefined owing to its multiple glycosylations. Although there have been many biochemical studies of the binding capacity of calcium, the study of the function of the domain is still deferred. By using S-200 gel filtration and Mono Q ion-exchange chromatographic procedures, NC can be purified without further treatment for the removal of urobilirubin. The kinetic study of crystal growth in calcium oxalate monohydrate is performed using a seed slurry system. NC was cut into two peptides through interaction with copper ion and ascorbic acid. The interaction site of the copper ion is presumed to be located between 8 and 6 kDa of molecular weight in NC. The data suggest that divalent metal ions may be involved in the calcium oxalate crystallization through interaction with NC. The role of ascorbic acid in the formation of urinary stones should be reappraised for its association in the redox reaction, with resultant protein digestion in the presence of copper ions.

Osteocalcin gene Hind III polymorphism is not correlated with calcium oxalate stone disease

The formation of urinary stones is presumed to be associated with polymorphism of the osteocalcin gene. The most frequently seen polymorphism is the Hind III type located at the promoter region. This polymorphism has been used as a genetic marker in the search for a correlation between urolithiasis and normal subjects. In our study, a normal control group of 105 healthy people and 102 patients with calcium oxalate stones were examined. The polymorphism was seen following polymerase chain reaction-based restriction analysis. The results revealed no significant differences between normal individuals and stone patients (P = 0.978), and distribution of the TT homozygote in the control group (42.9%) was similar to that in the patient group (42.2%). Further categorization of the stone patients into normocalciuric and hypercalciuric groups also revealed no statistical differences from controls. We conclude that Hind III polymorphism of the osteocalcin gene is not a suitable genetic marker of urinary stone disease. Further searches for other polymorphisms on this gene correlated with stone disease are suggested.

Stereocontrolled synthesis of acyclic 1,3-diols via condensation of tungsten-syn-pi-pentadienyl complexes with aldehydes. A new Prins reaction via s-trans-diene cationic intermediates

In the presence of BF(3).Et(2)O, condensation of CpW(CO)(2)(syn-pi-2-methoxycarbonylpentadienyl) with aldehydes generated tungsten-eta(4)-trans-diene cation in cold toluene, and hydrolysis of this salt afforded tungsten-pi-allyl-anti-1,3-diols in good yields. This new synthesis of anti-1,3-diols represents an atypical Prins reaction that is applicable to normal aldehydes. The anti/syn ratios of 1,3-diols increased with an increase in the size of the aldehydes. These anti-1,3-diols were transformed into various complex oxygen heterocycles based on two demetalations: (1) conversion to an allyl cation followed by nucleophilic attack and (2) condensation with aldehydes via its CpW(NO)Cl derivative, to give functionalized alpha-methylene butyrolactones. A semi-emperical calculation was performed to deduce the transition-state structure to rationalize the anti-stereoselectivity.

Paraneoplastic pemphigus in association with a retroperitoneal Castleman's disease presenting with a lichen planus pemphigoides-like eruption. A case report and review of literature

A 50-year-old man presented with severe mucosal erosions of the lips, oral cavity and perianal area, a lichen planus-like eruption on the trunk and extremities and scaly plaques of the palms and soles. The clinical impression was of Stevens--Johnson syndrome, or paraneoplastic pemphigus (PNP). Histopathology revealed vacuolar interface and lichenoid dermatitis with dyskeratosis and suprabasal acantholytic vesiculation. Direct immunofluorescence showed deposition of IgG in the intercellular space and linear deposition of C3 along the basal membrane zone. Indirect immunofluorescence revealed circulating IgG with intercellular staining of the epithelium of rat urinary bladder. Western blotting demonstrated bands of 250- and 230-kDa antigens. The clinical, histological and immunological features were consistent with the lichen planus pemphigoides variant of PNP. A retroperitoneal hyaline-vascular Castleman's disease was detected and excised. The skin lesions worsened initially after tumour resection but improved gradually, leaving extensive melanosis after cyclosporin and mycophenolate mofetil treatment.

Chronic health risks from aggregate exposures to ionizing radiation and chemicals: scientific basis for an assessment framework

Very little quantitative analysis is currently available on the cumulative effects of exposure to multiple hazardous agents that have either similar or different mechanisms of action. Over the past several years, efforts have been made to develop the methodologies for risk assessment of chemical mixtures, but mixed exposures to two or more dissimilar agents such as radiation and one or more chemical agents have not yet been addressed in any substantive way. This article reviews the current understanding of the health risks arising from mixed exposures to ionizing radiation and specific chemicals. Specifically discussed is how mixed radiation/chemical exposures, when evaluated in aggregation, were linked to chronic health endpoints such as cancer and intermediate health outcomes such as chromosomal aberrations. Also considered is the extent to which the current practices are consistent with the scientific understanding of the health risks associated with mixed-agent exposures. From this the discussion moves to the research needs for assessing the cumulative health risks from aggregate exposures to ionizing radiation and chemicals. The evaluation indicates that essentially no guidance has been provided for conducting risk assessment for two agents with different mechanisms of action (i.e., energy deposition from ionizing radiation versus DNA interactions with chemicals) but similar biological endpoints (i.e., chromosomal aberrations, mutations, and cancer). The literature review also reveals the problems caused by the absence of both the basic science and an appropriate evaluation framework for the combined effects of mixed-agent exposures. This makes it difficult to determine whether there is truly no interaction or somehow the interaction is masked by the scale of effect observation or inappropriate dose-response assumptions.

Association of the vitamin D receptor gene start codon Fok I polymorphism with calcium oxalate stone disease

OBJECTIVE

To assess the use of Fok I polymorphism (the most frequent polymorphism, at the start codon of the vitamin D receptor gene, VDR) as a convenient genetic marker in identifying the cause of urolithiasis.

PATIENTS, SUBJECTS AND METHODS

A normal control group of 90 healthy subjects and 146 patients with calcium oxalate stones were examined. Using polymerase chain reaction (PCR)-based restriction analysis, the relationship between Fok I polymorphism and urolithiasis was evaluated. An unexcisable length of 265 bp was identified (allele CC) and two fragments (169 bp and 96 bp) identified as excisable lengths (allele TT).

RESULTS

There was a statistically significant difference between the groups (chi-square test, P < 0.05) for the genotype of the VDR Fok I start codon polymorphism. The odds ratio (95% confidence interval) for the C allele in those at risk of stone disease was 1.672 (1.149-2.432).

CONCLUSIONS

These results suggest that the VDR Fok I start codon polymorphism may be a good candidate for a genetic marker in calcium oxalate stone disease.

Ticlopidine-induced hepatitis

Ticlopidine is a commonly prescribed drug in cerebrovascular or cardiovascular diseases. Since the first introduction in 1970's, ticlopidine was shown to be a relatively safe drug. The adverse effects of ticlopidine were mainly bone marrow toxicity and elevation of liver function tests. Ticlopidine-induced hepatitis is rare and only 33 cases were reported in previous English literature. The 33 cases were mostly categorized in cholestatic liver injury; only 2 cases were hepatocellular. In Taiwan, a case of ticlopidine-induced cholestatic hepatitis was ever reported. Herein, we present another rare case of ticlopidine-induced hepatitis in Taiwan with the nature of hepatocellular injury.

Food protein-induced enterocolitis syndrome: report of one case

We report a 76-day old infant who got diarrhea within the first week of life. He was treated as acute gastroenterocolitis and kept on feeding with regular infant formula. Because the symptoms persisted, the feeding formula was shifted to soy-based formula then to the highly-hydrolyzed formula and got improvement. But severe bloody diarrhea, vomiting, dehydration and fever developed after feeding with regular infant formula again. Based on the history and clinical presentations, cow's milk allergy was suspected. He received total parenteral nutrition for 5 days then fed with highly-hydrolyzed formula with slowly increasing amount. Thereafter tests for total eosinophil counts, total serum IgE, milk specific IgE antibodies and milk extract skin prick test were all unremarkable. Under the impression of food protein-induced enterocolitis syndrome (FPIES), a double-blind placebo-controlled food challenge (DBPCFC) with infant formula was performed. Regular infant formula induced severe vomiting, diarrhea, fever, acidosis and elevation of absolute neutrophil counts (ANC) of peripheral blood by 27,640/mm3. Based on the laboratory findings and challenge results, the patient fit the diagnostic criteria of food protein-induced enterocolitis syndrome.

Fluoxetine-induced Ca2+ signals in Madin-Darby canine kidney cells

The effect of fluoxetine on Ca2+ signaling in Madin-Darby canine kidney (MDCK) cells was investigated by using fura-2 as a Ca2+ probe. Fluoxetine increased [Ca2+]i concentration-dependently between 5 microM and 200 microM with an EC50 value of 40 microM. The response was reduced by external Ca2+ removal by 30%40%. In Ca2+-free medium pretreatment with 1 microM thapsigargin, an inhibitor of the endoplasmic reticulum Ca2+ pump, abolished 100 microM fluoxetine-induced Ca2+ release. Addition of 3 mM Ca2+ to Ca2+-free medium increased [Ca2+]i when cells were pretreated with 100 microM fluoxetine. Suppression of 1,4,5-trisphosphate (IP3) formation by 2 microM U73122 (a phospholipase C inhibitor) did not affect 100 microM fluoxetine-induced Ca2+ release. Fluoxetine (5-100 microM) also increased [Ca2+]i in neutrophils, prostate cancer cells and bladder cancer cells from human and rat glioma cells.

Prevalence and significance of hepatitis B virus (HBV) pre-S mutants in serum and liver at different replicative stages of chronic HBV infection

Several types of naturally occurring pre-S mutants in sera or liver tissues in patients with chronic hepatitis B virus (HBV) infection have been identified. To clarify the prevalence and significance of emergence of pre-S mutants, 140 sera and 18 resected livers from patients with HBV were studied. Replicative status was designated as high, intermediate, and low based on the HBV-DNA levels in serum or the expression of HBV antigens in liver. In vitro transfection and Western blot analysis were performed to characterize expression and secretion of HBsAg by the mutant constructs. Five major types (I to V) of pre-S deletion mutants in serum and liver and 2 types (VI and VII) in liver were identified. Pre-S mutant was 6.4% at high replicative phase, 13% at intermediate, and 37.5% at low or nonreplicative phases in serum. In livers, the same tendency existed: pre-S2 deletion mutants emerged and prevailed at a low replicative phase in hepatocytes that expressed a novel marginal pattern of HBsAg and usually clustered in groups. The deletion sequence of pre-S2 region coincides with human leukocyte antigen-restricted T- and B-cell epitopes. In vitro HBsAg was retained in the hepatocytes and synthesis and secretion of major surface antigen decreased for most of the pre-S mutants. Pre-S mutants prevailed with evolution of chronic HBV, probably under immune pressure. Emergence of pre-S mutants may account for the life-long persistence and discrepancy of HBsAg in serum and liver in HBV and may confer growth advantage in view of the clustering proliferation of hepatocytes harboring pre-S2 mutant.

Biological effects and metabolism of 9-cis-retinoic acid and its metabolite 9,13-di-cis-retinoic acid in HaCaT keratinocytes in vitro: comparison with all-trans-retinoic acid

9-cis-Retinoic acid (9cRA), a geometric isomer of all-trans-retinoic acid (atRA), is an endogenous high-affinity ligand for retinoid X receptors and retinoic acid receptors activating them with high potency. 9,13-di-cis-Retinoic acid (9,13dcRA) has been described as a major plasma metabolite of 9cRA. In this study, the biological activity and the metabolism of 9cRA and 9,13dcRA were investigated and compared with those of atRA in a retinol-free culture system of HaCaT keratinocytes. 9cRA exhibited a slightly weaker activity overall than atRA in inhibiting cell proliferation, inducing cellular retinoic acid binding protein II (CRABP II) mRNA levels and upregulating cytokeratin 19 expression. 9,13dcRA regulated HaCaT keratinocyte activity only at the highest concentration tested (10(-6) M). In cultures of HaCaT keratinocytes with atRA and 9cRA, rapid intracellular accumulation of atRA was observed within 2 h, and atRA levels were higher with atRA treatment than with 9cRA treatment. 9,13dcRA remained relatively stable in the medium with intracellular 9,13dcRA levels below the level of detection. Taken together, 9cRA seems to be slightly less potent than atRA in regulating the biological activity of HaCaT keratinocytes, while its metabolite 9,13dcRA is effectively inactive at biologically relevant concentrations. Our data suggest a prodrug/drug relationship between 9cRA and atRA in human keratinocytes. 9,13dcRA seems to be a weaker prodrug of atRA or an inactive metabolic derivative.

New jujubogenin glycosides from Colubrina asiatica

Three new jujubogenin glycosides, namely, 3' '-O-acetylcolubrin (1); 3' ',2' "-O-diacetylcolubrin (2), and 3' '-O-acetyl-6' '-O-trans-crotonylcolubrin (3), were isolated from the leaves of Colubrina asiatica, in addition to the known colubrin, rutin, and kaempferol 3-O-rutinoside. Compounds 1-3 were isolated and purified via a combination of chromatographic procedures, and determined structurally using spectroscopic methods.

Distributions of p53 codon 72 polymorphism in bladder cancer--proline form is prominent in invasive tumor

Abnormal function of p53 is commonly associated with various cancer formations. High-grade and late-stage bladder cancers have been reported to have mutated or become inactive p53 when using immunohistochemical stains. Recently, p53 codon 72 polymorphism was extensively studied to determine the risk factors responsible for cancer formation. There was a general population of codon 72 sequence polymorphism of the wild type p53. A single base change from G to C caused the alteration of amino acid residue 72 from arginine to proline. The arginine form is considered to be a significant risk factor in the development of cancer. However, various reports had indicated discrepancies with regard to this polymorphism; some showed no significant difference between the control and cancer groups, while other series were associated with high risks in the proline form homozygotes. To resolve the undefined distribution of this polymorphism in bladder cancers, 58 patients with bladder cancer were enrolled onto this study. When checked using the Chi-squared test (P = 0.952) there were no differences between the control subjects and bladder cancer patients in the distribution of polymorphism. However, proline form homozygotes were more frequently found in the invasive group than the non-invasive group by Fisher's exact test (25% and 2.9%, respectively, P < 0.001). More than 70% of the non-invasive bladder cancers were the arginine form homozygotes. This result is consistent with those reported for hepatocellular carcinoma that showed a history of chronic liver disease and proline form homozygotes in a report by Yu et al. Our data suggest that proline form homozygotes are associated with invasive bladder cancer.

Lindane (gamma-hexachlorocyclohexane) induces internal Ca2+ release and capacitative Ca2+ entry in Madin-Darby canine kidney cells

The effect of lindane (gamma-hexachlorocyclohexane), an organochlorine pesticide, on Ca2+ mobilization in Madin-Darby canine kidney cells was examined by fluorimetry using fura-2 as a Ca2+ indicator. Lindane (5-200 microM) increased [Ca2+]i concentration-dependently. The [Ca2+]i signal comprised an immediate initial rise followed by a persistent phase. Ca2+ removal inhibited the [Ca2+]i signal by reducing both the initial rise and the sustained phase. This implies lindane-triggered Ca2+ influx and Ca2+ release. In Ca2+ -free medium, 0.15 mM lindane increased [Ca2+]i after pretreatment with carbonylcyanide m-chlorophenylhydrazone (CCCP, 2 microM), a mitochondrial uncoupler, and two endoplasmic reticulum Ca2+ pump inhibitors, thapsigargin and cyclopiazonic acid. Conversely, pretreatment with lindane abolished CCCP- and thapsigargin-induced Ca2+ release. This suggests that 0.15 mM lindane released Ca2+ from the endoplasmic reticulum, mitochondria and other stores. La3+ (1 mM) partly inhibited 0.1 mM lindane-induced [Ca2+]i increase, confirming that lindane induced Ca2+ influx. Addition of 3 mM Ca2+ increased [Ca2+]i after pretreatment with 0.15 mM lindane for 750 sec. in Ca2+ -free medium, which indicates lindane-induced capacitative Ca2+ entry. Lindane (0.15 mM)-induced Ca2+ release was not reduced by inhibiting phospholipase C with 2 microM U73122, but was inhibited by 70% by the phospholipase A2 inhibitor aristolochic acid (40 microM).

Dual action of palmitoyl trifluoromethyl ketone (PACOCF3) on Ca2+ signaling: activation of extracellular Ca2+ influx and alteration of ATP- and bradykinin-induced Ca2+ responses in Madin Darby canine kidney cells

The effect of the phospholipase A2 inhibitor palmitoyl trifluoromethyl ketone (PACOCF3) on Ca2+ signaling in Madin Darby canine kidney (MDCK) cells was examined using fura-2 as the fluorescent Ca2+ indicator. At a concentration of 20 microM, PACOCF3 did not change basal cytosolic free calcium concentrations ([Ca2+]i), but at concentrations of 50-250 microM PACOCF3 induced an increase in [Ca2+]i by activating extracellular Ca2+ entry which was partly suppressed by 50 microM La3+. The effect of PACOCF3 was abolished by removal of extracellular Ca2+. PACOCF3 (10 microM) enhanced both the peak value and the area under the curve of the [Ca2+]i increase induced by 10 microM ATP and 1 microM bradykinin by potentiating extracellular Ca2+ influx without affecting internal Ca2+ release. Several other phospholipase A2 inhibitors had no effect on basal [Ca2+]i or agonist-induced [Ca2+]i increases. Collectively, the results suggest that PACOCF3 alters Ca2+ signaling in renal tubular cells in a manner independent of phospholipase A2 inhibition.

Does Ser364Pro mutation of connexin 43 exist in Taiwanese patients with Ivemark syndrome?

BACKGROUND

A previous study by Britz-Cunningham et al (N Engl J Med, 1995) indicated that a mutation of the connexin 43 (CX43) gap junction gene might be responsible for Ivemark syndrome. Ser364Pro substitution (TCA-->CCA) is the most common mutation located in the cytoplasmic tail domain of CX43. This domain may be an important part of the conductance channel of the gap junction. It may, therefore, result in heart anomalies and situs inversus during embryonic development, resulting in Ivemark syndrome.

METHODS

We investigated 10 patients with Ivemark syndrome, 10 healthy individuals, one patient with Kartagener syndrome and one with polysplenia and situs inversus but without heart anomaly for this mutation. Seminested polymerase chain reaction (PCR) was performed using a DNA template from DNA extracted from peripheral blood cells. Direct sequencing was done after purification of the second round of PCR products. Then, the sequence was compared with the last 402 bp of the cDNA-coding region of CX43.

RESULTS

No base changes were found in the patients with Ivemark syndrome or other patient groups at the previously reported CX43 residues of Thr326, Gln352, Ser364, Ser365 and Ser373.

CONCLUSIONS

The results indicate that Ser364Pro mutation of CX43 did not exist in the 10 Taiwanese patients with Ivemark syndrome. Other genes responsible for the Ivemark syndrome should be further investigated.

Mutation analysis of human LEFTY A and LEFTY B genes in children with Ivemark syndrome

The search for genes responsible for the abnormal development of the left-right (L/R) asymmetry has been conducted but no definite results have been reported. Recently, two human homologus mouse lefty1 genes, LEFTY A and LEFTY B, were analyzed for mutations in patients with the L/R anomalies. However, only two mutations were found in a survey of 126 patients. We collected genomic DNA from 10 children with Ivemark syndrome, a disease with anomalies in L/R asymmetry. Mutation analysis of LEFTY A and LEFTY B genes using single strand conformation polymorphism and direct sequencing was performed, but no mutations were found. This indicates that the L/R asymmetry anomaly in Ivemark syndrome may not be caused by the mutation of LEFTY A and LEFTY B genes. Other genes responsible for the anomalies of L/R asymmetry should be further investigated.

The effect of nodal status on determinants of initial treatment response and patterns of relapse-free survival in nasopharyngeal carcinoma

PURPOSE

To study the effect of regional nodal status on predictors of treatment response, failure patterns, and the time-dependent nature of the various pattern of relapse via a hazard function analysis.

METHODS AND MATERIALS

We reviews tumor control data of 496 patients with nasopharyngeal carcinoma (NPC) to whom a radical course of radiotherapy (RT) with or without induction chemotherapy (CT) was given. All alive patients had a median follow-up period of 131 months. Primary tumor (T) and nodal (N) status were staged according to the TNM system of the American Joint Committee. Remote after-loading brachytherapy may be added to teletherapy in T1-2 lesions while induction CT could be given for N3 and/or T4 lesions. Hazard function analysis over 1-year interval was carried out for locoregional or distant relapse.

RESULTS

T stage and brachytherapy were two independent predictors for complete response (CR) at the primary site irrespective of nodal status, whereas N stage and brachytherapy are major determinants for regional CR in node (+) patients. Multivariate analysis revealed that contributors to a relatively long disease-free interval in (1) node (-) patients were for locoregional relapse, induction CT(-) (p = 0.0062) or brachytherapy (+) (p = 0.0268) and for distant relapse, none; (2) node (+) patients were for locoregional relapse, early T stage (p = 0.0377) or regional CR (p = 0.0075) and for distant relapse, induction CT(-) (p = 0.0001) or regional CR (p = 0.0001). In node (-) or (+) patients, primary CR rate yield no independent prognostic value on various types of disease-free survival. Hazard function analysis for relapse revealed that hazard rates are in general negatively correlated with time, being highest at the first year post-treatment, decreasing from time to time, and approaching zero after a longer follow-up period in patients with locoregional CR than in patients without.

CONCLUSION

Nodal status had no significant impact on predictors of primary CR, whereas in node (+) patients regional CR rate had an independent value in predicting disease-free survival to locoregional and distant relapse. Hazard function analysis revealed a decreasing hazard rate over a protracted post-treatment time in primary and regional CR patients. This indicates the continued risk of late recurrence in this subset of patients for whom long-term observation is recommended.