High failure rate of the dissolution tests for 500-mg amoxicillin capsules sold in Cambodia: is it because of the product or the test method?

OBJECTIVES: During the survey of substandard medicines in Cambodia in 2007, it was found that more than 90% of 500-mg amoxicillin (AMPC) capsules failed the United States Pharmacopeia (USP) 30 TEST 1 dissolution test. In the USP, several monographs provide multiple methods for performing the dissolution test. By using the 500-mg AMPC capsule as an example, we aimed to identify the problems and implications of the USP methods adopted for the dissolution test as a global standard. METHODS: All AMPC samples were collected from the Cambodian market in 2007. For the quantitative test, we referred to USP 30. We performed the USP 28 and USP 30 TEST 2 dissolution tests and compared these results with those of the USP 30 TEST 1. RESULTS: All 500-mg AMPC capsules used for the comparison passed the quantitative test. Samples that passed the USP 28 and USP 30 TEST 2 dissolution tests were identical, and the pass rate was 97.1% (34/35), whereas the pass rate with the USP 30 TEST 1 was 8.6% (3/35). The difference in the dissolution results between the three methods was significant (P<0.0001). CONCLUSION: This study revealed that many users would select the most stringent method when multiple methods exist in the USP. This may lead to a high failure rate of the tests. Because USP is a global standard, we recommend that it take into consideration the developing countries and create a more detailed user-friendly manual for selection for appropriate methods.

Effects of regular and low-fluoride dentifrices on plaque fluoride.

Previous studies have indicated that the use of low-fluoride dentifrices could lead to proportionally higher plaque fluoride levels when compared with conventional dentifrices. This double-blind, randomized, crossover study determined the effects of placebo, low-fluoride, and conventional dentifrices on plaque fluoride concentrations ([F]) in children living in communities with 0.04, 0.72, and 3.36 ppm F in the drinking water. Children used the toothpastes twice daily, for 1 wk. Samples were collected 1 and 12 hrs after the last use of dentifrices and were analyzed for fluoride and calcium. Similar increases were found 1 hr after the children brushed with low-fluoride (ca. 1.9 mmol F/kg) and conventional (ca. 2.4 mmol F/kg) dentifrices in the 0.04- and 0.72-ppm-F communities. Despite the fact that the increases were less pronounced in the 3.36-ppm-F community, our results indicate that the use of a low-fluoride dentifrice promotes a proportionally higher increase in plaque [F] when compared with that achieved with a conventional dentifrice, based on dose-response considerations.

The supernumerary chromosome of Nectria haematococca that carries pea-pathogenicity-related genes also carries a trait for pea rhizosphere competitiveness.

Fungi are found in a wide range of environments, and the ecological and host diversity of the fungus Nectria haematococca has been shown to be due in part to unique genes on different supernumerary chromosomes. These chromosomes have been called "conditionally dispensable" (CD) since they are not needed for axenic growth but are important for expanding the host range of individual isolates. From a biological perspective, the CD chromosomes can be compared to bacterial plasmids that carry unique genes that can define the habits of these microorganisms. The current study establishes that the N. haematococca PDA1-CD chromosome, which contains the genes for pea pathogenicity (PEP cluster) on pea roots, also carries a gene(s) for the utilization of homoserine, a compound found in large amounts in pea root exudates. Competition studies demonstrate that an isolate that lacks the PEP cluster but carries a portion of the CD chromosome which includes the homoserine utilization (HUT) gene(s) is more competitive in the pea rhizosphere than an isolate without the CD chromosome.

p21 provides stage specific DNA damage control to preimplantation embryos.

The early stage embryogenesis of higher eukaryotes lacks some of the damage response pathways such as G1/S checkpoint, G2/M checkpoint and apoptosis. We examined here the damage response of preimplantation stage embryos after fertilization with 6 Gy irradiated sperm. Sperm-irradiated embryos developed normally for the first 2.5 days, but started to exhibit a developmental delay at day 3.5. p21 was activated in the delayed embryos, which carried numerous micronuclei owing to delayed chromosome instability. Apoptosis was observed predominantly in the inner cell mass of the day 4.0 embryos. Sperm-irradiated p21-/- embryos lacked the delay, but chromosome instability and apoptosis were more pronounced than the corresponding p21 wild-type embryos. We conclude from the result that damage responses come in a stage-specific manner during preimplantation stage development; p53-dependent S checkpoint at the zygote stage, p21-mediated cell cycle arrest at the morula/blastocyst stages and apoptosis after the blastocyst stage in the inner cell mass.

Chromosome complement of the fungal plant pathogen Fusarium graminearum based on genetic and physical mapping and cytological observations.

A genetic map of the filamentous fungus Fusarium graminearum (teleomorph: Gibberella zeae) was constructed to both validate and augment the draft whole-genome sequence assembly of strain PH-1. A mapping population was created from a cross between mutants of the sequenced strain (PH-1, NRRL 31084, originally isolated from Michigan) and a field strain from Minnesota (00-676, NRRL 34097). A total of 111 ascospore progeny were analyzed for segregation at 235 loci. Genetic markers consisted of sequence-tagged sites, primarily detected as dCAPS or CAPS (n = 131) and VNTRs (n = 31), in addition to AFLPs (n = 66) and 7 other markers. While most markers exhibited Mendelian inheritance, segregation distortion was observed for 25 predominantly clustered markers. A linkage map was generated using the Kosambi mapping function, using a LOD threshold value of 3.5. Nine linkage groups were detected, covering 1234 cM and anchoring 99.83% of the draft sequence assembly. The nine linkage groups and the 22 anchored scaffolds from the sequence assembly could be assembled into four chromosomes, leaving only five smaller scaffolds (59,630 bp total) of the nuclear DNA unanchored. A chromosome number of four was confirmed by cytological karyotyping. Further analysis of the genetic map data identified variation in recombination rate in different genomic regions that often spanned several hundred kilobases.

Strict red blood cell transfusion guideline reduces the need for transfusions in very-low-birthweight infants in the first 4 weeks of life: a multicentre trial.

BACKGROUND AND OBJECTIVES: Very-low-birthweight infants are among the most heavily transfused patients. The objective of this study was to verify if the introduction of a strict guideline would reduce the need for red blood cell transfusions in the first 4 weeks of life in these neonates. MATERIALS AND METHODS: This was a multicentre prospective study of two cohorts of very-low-birthweight infants transfused in accordance with the recommendations of a neonatologist (Phase 1) or according to previously published guidelines (Phase 2). RESULTS: In the first 28 days of life, 102 patients (68.5%) in Phase 1 and 117 (59.7%) in Phase 2 were transfused. The number of transfusions was 1.9 +/- 2.0 in Phase 1 and 1.4 +/- 1.6 in Phase 2 (P = 0.01). After adjusting for gestational age, blood loss and the presence of respiratory distress syndrome, the strict guideline reduced the number of transfusions in 17.6% (IC 95%-30.5% to -2.6%). CONCLUSIONS: The strict guideline was effective in reducing erythrocyte transfusions in very-low-birthweight infants.

Meiotic behavior of a supernumerary chromosome in Magnaporthe oryzae.

A 1.2-Mb DNA band from an isolate of Magnaporthe oryzae was detected in a pulsed-field gel. A chromosomal entity corresponding to this band was observed at the mitotic metaphase stage. This minichromosome, carrying many transposable elements and two telomeres, was transmitted to ascosporic F(1) cultures in a non-Mendelian manner with frequent changes in its size and number. Segregation analysis with RFLP markers indicated that the minichromosome underwent structural rearrangements, such as deletion and duplication, not only during meiosis but also after meiosis. An ectopic sister chromatid recombination may cause the size variation of the minichromosomes.

The LuxS-dependent autoinducer AI-2 controls the expression of an ABC transporter that functions in AI-2 uptake in Salmonella typhimurium.

In a process called quorum sensing, bacteria communicate with one another using secreted chemical signalling molecules termed autoinducers. A novel autoinducer called AI-2, originally discovered in the quorum-sensing bacterium Vibrio harveyi, is made by many species of Gram-negative and Gram-positive bacteria. In every case, production of AI-2 is dependent on the LuxS autoinducer synthase. The genes regulated by AI-2 in most of these luxS-containing species of bacteria are not known. Here, we describe the identification and characterization of AI-2-regulated genes in Salmonella typhimurium. We find that LuxS and AI-2 regulate the expression of a previously unidentified operon encoding an ATP binding cassette (ABC)-type transporter. We have named this operon the lsr (luxS regulated) operon. The Lsr transporter has homology to the ribose transporter of Escherichia coli and S. typhimurium. A gene encoding a DNA-binding protein that is located adjacent to the Lsr transporter structural operon is required to link AI-2 detection to operon expression. This gene, which we have named lsrR, encodes a protein that represses lsr operon expression in the absence of AI-2. Mutations in the lsr operon render S. typhimurium unable to eliminate AI-2 from the extracellular environment, suggesting that the role of the Lsr apparatus is to transport AI-2 into the cells. It is intriguing that an operon regulated by AI-2 encodes functions resembling the ribose transporter, given recent findings that AI-2 is derived from the ribosyl moiety of S-ribosylhomocysteine.

[Case of protein-losing gastroenteropathy associated with scleroderma in which central serous chorioretinopathy developed].

A 44-year-old woman noticed edema of the lower limbs in May 1999 and visited our hospital in September 1999 to undergo further examination. On admission, severe hypoalbuminemia (1.9 g/dl) was detected with a negative urinary protein level. Protein leakage into the gastrointestinal tract and deposition of immune complex in the colonic mucosa were shown by the fluorescent antibody method. In addition, anti-centromere antibody, sclerodactyly, and findings indicative of histological sclerotic changes on a skin biopsy were observed. These findings supported a diagnosis of protein-losing gastroenteropathy complicated by scleroderma. Administration of oral corticosteroids was begun one month after admission and the patient experienced diminished visual acuity immediately after steroid pulse therapy in November. Central serous chorioretinopathy (CSC) was diagnosed at the Department of Ophthalmology of our hospital, and the administration of corticosteroids was suspected as a possible cause of CSC. Considering the severity of hypoproteinemia, the corticosteroid treatment was continued despite corticosteroids being strogly suspected as the primary cause of CSC. A complete disappearance of CSC was achieved in 30 days after the onset of symptoms despite continuation of the steroid therapy, and her serum albumin and complement levels both normalized. We concluded that damage to the retinal pigment epithelium secondary to the vascular lesion at the choroidal level plays a causative role in CSC. In the present case, the findings suggested that the deposition of immune complex in choroidal tissues as well as the gastrointestinal tract caused hyperpermeability of choroidal vessels and led to the development of CSC.

Cytological Karyotyping of Three Cochliobolus spp. by the Germ Tube Burst Method.

ABSTRACT Cytological karyotypes with mitotic metaphase chromosomes were analyzed for Cochliobolus heterostrophus, C. carbonum, and C. sativus by the germ tube burst method (GTBM). Prior to karyotyping, procedures of GTBM suitable to Cochliobolus were established by examining several crucial conditions such as incubation period of conidia. The estimated chromosome numbers of C. heterostrophus and C. carbonum were n = 15 or 16 and n = 13 or 15 depending on the strains, respectively. In C. sativus, n = 15 was estimated. Morphological information of chromosomes including chromosome size and a threadlike-specific structure representing the nucleolar organizing region was also obtained. Our results for some standard strains are in agreement with previous estimates by pulsed field gel electrophoresis (PFGE) or PFGE coupled with restriction fragment length polymorphism genetic linkage analysis, but inconsistent with the previous estimates for other strains by conventional light microscopic cytology. Additionally, PFGE analysis of C. heterostro-phus strains indicated that chromosome number was not determinable solely by PFGE, which is hampered by comigration and clumping of DNA bands.

Increased frequencies of gene and chromosome mutations after X-irradiation in mouse embryonal carcinoma cells transfected with the bcl-2 gene.

Preimplantation stage mouse embryos are known to be highly sensitive to the killing effect of DNA-damaging agents such as radiation. Interestingly, however, this stage of development is well protected from radiation induction of malformation and carcinogenesis in postnatal life. In recent years, it has become clear that the stem cells of preimplantation stage embryos undergo extensive apoptosis after DNA damage. It has been postulated that this apoptosis is likely to be responsible for the resistance to malformation, by excluding cells carrying deleterious DNA damage. We have tested the possible role of apoptosis in elimination of gene and chromosome mutations in undifferentiated mouse embryonal carcinoma cell line, F9, transfected with human bcl-2 cDNA. The colony radiosensitivity of F9 cells was not affected by overexpression of the bcl-2 gene, but the apoptotic cell death was suppressed, as examined by DNA ladder assay and Hoechst staining. This suppression was accompanied by an increase in the frequencies of hprt mutation and micronucleus formation after X-irradiation. These results support the idea that maintenance of genomic integrity during early development is likely to be executed by apoptotic elimination of cells at risk.

Biological action of keratinocyte growth factor in BeWo cells, a human choriocarcinoma cell line.

Previously, we reported that the expression of keratinocyte growth factor (KGF) is enhanced in secretory phase endometrial and decidual cells in early pregnancy as compared with the expression of KGF in proliferative phase endometrial cells, in humans. In order to clarify the role of KGF in embryo-endometrial interaction, we analyzed the in vitro effect of KGF on the human chorionic gonadotropin (hCG) secretion and on DNA synthesis in chorionic villi which are in close contact with the endometrium/decidua in the early stage of pregnancy. In this study, we used the BeWo cell line, a human choriocarcinoma cell line that possesses the biological features of secreting various placental hormones including hCG. Furthermore, we investigated the expression of KGF receptor (KGF-R) in these cells. KGF significantly stimulated hCG secretion in cultured BeWo cells but did not affect [3H]-thymidine incorporation. KGF-R mRNA was detected in BeWo cells by reverse transcriptase-polymerase chain reaction. These results suggest that the expression of KGF, which is induced in endometrial/decidual cells by progesterone, plays an important role in the embryo-endometrial/ decidual interaction by stimulating hCG secretion rather than affecting cell proliferation.

Role of the cAMP signaling pathway in the regulation of gonadotropin-releasing hormone secretion in GT1 cells.

We studied the signaling pathways coupling gonadotropin-releasing hormone (GnRH) secretion to elevations in cAMP levels in the GT1 GnRH-secreting neuronal cell line. We hypothesized that increased cAMP could be acting directly by means of cyclic nucleotide-gated (CNG) cation channels or indirectly by means of activation of cAMP-dependent protein kinase (PKA). We showed that GT1 cells express the three CNG subunits present in olfactory neurons (CNG2, -4.3, and -5) and exhibit functional cAMP-gated cation channels. Activation of PKA does not appear to be necessary for the stimulation of GnRH release by increased levels of cAMP. In fact, pharmacological inhibition of PKA activity caused an increase in the basal secretion of GnRH. Consistent with this observation activation PKA inhibited adenylyl cyclase activity, presumably by inhibiting adenylyl cyclase V expressed in the cells. Therefore, the stimulation of GnRH release by elevations in cAMP appears to be the result of depolarization of the neurons initiated by increased cation conductance by cAMP-gated cation channels. Activation of PKA may constitute a negative-feedback mechanisms for lowering cAMP levels. We hypothesize that these mechanisms could result in oscillations in cAMP levels, providing a biochemical basis for timing the pulsatile release of GnRH.

A case of postpregnancy osteoporosis.

A puerperant woman, who was previously healthy and had no disease known to affect bone metabolism, experienced lower back pain and lumbar vertebral fractures during lactation. Both bone formation markers and resorption markers were markedly elevated. Bone mineral density of the lumbar spine as measured by dual energy X-ray absorptiometry was extremely low. She stopped lactation through the use of bromocriptine because of the large volume of milk secretion. After treatment with calcitonin injections and the use of a corset, her back pain gradually disappeared. This case appears to be postpregnancy osteoporosis.

[Polyarthralgia as the initial manifestation of isolated ACTH deficiency].

A 57-year-old man, employed as a taxi driver, noticed arthralgia of his fingers beginning in May 1999. He was unable to work due to the arthralgia and the accompanying general malaise and anorexia, and was thus admitted to a local hospital in July 1999. Since a diagnosis of rheumatic disease was suspected due to elevated inflammatory reactions and joint symptoms, he was referred to our hospital in September 1999. Although no joint swelling was observed, severe tenderness was present in both the fingers and wrists. His grasping power had decreased markedly and fever was intermittently observed. All autoantibodies aside from antinuclear antibody were negative. Given that hyponatremia (126 mEq/l) and fasting hypoglycemia were demonstrated, an endocrinological examination, in particular for hypopituitary-adrenal function, was performed. Both plasma and urinary cortisol concentrations were very low, and an associated low concentration of plasma ACTH (6.0 pg/ml) was noted. The ACTH circadian rhythm was absent and there was no response to the administration of corticotropin releasing hormone. All other pituitary hormones were secreted at normal levels and brain MRI revealed a normal appearance of a pituitary gland. Based on these findings, the patient was diagnosed as having isolated ACTH deficiency. Arthralgia and general malaise both improved soon after replacement of glucocorticoid, and CRP levels were normalized. Isolated ACTH deficiency should be considered in the differential diagnosis of patients suffering from polyarthralgia, given that fever and increased inflammatory reactions occasionally develop and that rheumatic symptoms are also present, as in the present case.

The effect of caffeine on p53-dependent radioresponses in undifferentiated mouse embryonal carcinoma cells after X-ray and UV-irradiations.

The effect of caffeine was studied on the radioresponses of undifferentiated mouse embryonal carcinoma cells (EC cells) with or without the functional p53. The radioresponses studied included radiosensitivity, the activation of p53, apoptosis with characteristic DNA ladder formation and cell cycle progression. An undifferentiated mouse EC cell line, ECA2, and a newly established p53-deficient EC cell line, p53 delta, were used in the present study. The status of the p53 gene did not significantly affect the colony survivals of undifferentiated EC cells to X-rays and UV. Although a post-irradiation treatment with caffeine sensitized both lines to X-rays marginally, the sensitization was prominent for UV regardless of the p53 status of the cells. The activation of a p53 responsible lacZ reporter construct was observed in stably transfected ECA2 cells after X-ray and UV irradiations. Caffeine suppressed the X-ray induced activation of the lacZ reporter, while it drastically enhanced the activation after UV irradiation. X-rays and UV readily triggered the apoptosis of ECA2 cells with the characteristic DNA ladder. Although UV-induced DNA ladder formation was enhanced by caffeine, that induced by X-rays was unaffected. Therefore, the effects of caffeine on the p53-dependent radioresponses were found to be agent specific: suppression for the X-ray induced and augmentation for the UV induced. In contrast to p53-proficient ECA2 cells, smear-like DNA degradation was observed for irradiated p53 delta cells, suggesting the presence of a mode of cell death without DNA ladder formation. UV induction of the smear-like DNA degradation was enhanced in the presence of caffeine. Regardless of the state of the p53 gene, G1/S arrest was not observed in X-ray and UV irradiated EC cells. X-ray induced G2/M arrest in both lines, which was abrogated by caffeine, while G2/M arrest after UV was unaffected by a caffeine treatment. These results indicate that the radioresponses of undifferentiated EC cells differ considerably from those of somatic cells, and that these radioresponses were modulated by a post-irradiation treatment with caffeine.

A double-masked multicenter comparative study between alendronate and alfacalcidol in Japanese patients with osteoporosis. The Alendronate Phase III Osteoporosis Treatment Research Group.

To evaluate the efficacy and safety of alendronate, a double-masked, active (alfacalcidol) controlled comparative study for 48 weeks was carried out in a total of 210 Japanese patients with osteoporosis. The doses of alendronate and alfacalcidol were 5 mg/day and 1 microgram/day, respectively. The lumbar bone mineral density (LBMD) values observed at 12, 24, 36 and 48 weeks after the initiation of alendronate treatment were 3.53 +/- 0.53%, 5.37 +/- 0.62%, 5.87 +/- 0.74% and 6.21 +/- 0.59% (mean +/- SE), respectively, higher than the baseline value. Corresponding values in the alfacalcidol group were 1.50 +/- 0.43%, 0.69 +/- 0.63%, 1.12 +/- 0.60% and 1.36 +/- 0. 63%, respectively. There was a significant difference between the two groups at each time point (p<0.05 or p<0.001). The bone turnover markers were depressed during treatment in the alendronate group: -32.2% for alkaline phosphatase, -53.7% for N-terminal osteocalcin and -45.0% for urinary deoxypyridinoline compared with the corresponding baseline values. On the contrary, no notable changes in these parameters were observed in the alfacalcidol group. Treatment with alendronate caused a transient decrease in serum calcium concentrations associated with an increase in the serum level of intact parathyroid hormone. In contrast, treatment with alfacalcidol resulted in a tendency of these parameters to change in the opposite direction. No difference in fracture incidence between the two groups was observed. The overall safety of alendronate was comparable to that of alfacalcidol. In conclusion, although it was a relatively short-term study of 48 weeks, the results of the present study indicate that alendronate at the daily dose of 5 mg was effective in increasing LBMD and that no serious drug-related adverse events were observed in the alendronate-treated patients. Alendronate is more efficacious than alfacalcidol in increasing bone mineral density, although the mechanisms of the actions of the two drugs are apparently different.

Molecular karyotypes for Alternaria plant pathogens known to produce host-specific toxins.

There are at least ten plant diseases caused by Alternaria species in which host-specific toxins (HSTs) are responsible for fungal pathogenicity. Of these HST-producers, seven are considered distinct pathotypes of the species Alternaria alternata, and the remaining three are among other species of pathogenic Alternaria. Inter- and intra-specific variation among Alternaria taxa, including HST-producers, was determined by electrophoretic karyotyping using pulsed-field gel electrophoresis. A. alternata including seven pathotypes of A. alternata and eight non-pathogenic strains had 9-11 chromosomal bands with estimated sizes ranging from 0.4 to 5.7 Mb. In contrast, Alternaria species that are morphologically distinct from A. alternata had 8-10 bands with sizes between 0.9 and 5.7 Mb. Estimated genome sizes of A. alternata and other Alternaria species ranged from 28.8 to 33.6 Mb and 25.1 to 30.7 Mb, respectively. Other species of pathogenic Alternaria were difficult to differentiate from A. alternata on the basis of chromosome-size polymorphisms alone, but Southern analysis using rDNA as a probe could, in some cases, differentiate between them. These results were cytologically confirmed by 4',6-diamidino-2-phenylindole (DAPI) staining and fluorescence in situ hybridization with a rDNA probe for mitotic metaphase chromosomes prepared by the germ-tube burst method.

Visualization of a conditionally dispensable chromosome in the filamentous ascomycete Nectria haematococca by fluorescence in situ hybridization.

Supernumerary chromosomes, termed "conditionally dispensable" (CD) chromosomes, are known in Nectria haematococca. Because these CD chromosomes had been revealed solely by pulsed-field gel electrophoresis, their morphological properties were unknown. In this study, we visualized a 1.6-Mb CD chromosome of this fungus by three different types of fluorescence in situ hybridization. The CD chromosome at mitotic metaphase was similar in its appearance to the other chromosomes in the genome. Heterochromatic condensation was not distinct in the CD chromosome, suggesting that it is primarily euchromatic. It was also evident that the CD chromosome is unique and not a duplicate of other chromosomes in the genome. At interphase and prophase, the CD chromosome was not dispersed throughout the nucleus, but occupied a limited domain. Occasionally, occurrence of two distinct unattached copies of the CD chromosome were observed during interphase and metaphase.