Bortezomib (VELCADE®) in metastatic breast cancer: pharmacodynamics, biological effects, and prediction of clinical benefits

BACKGROUND

Bortezomib (VELCADE) is a potent inhibitor of the 26S proteasome with broad antitumor activity. We performed a phase II study of bortezomib to evaluate its clinical effects in patients with metastatic breast cancer.

PATIENTS AND METHODS

Twelve patients with metastatic breast cancer were treated with bortezomib (VELCADE) at a dosage of 1.5 mg/m(2) administered biweekly for 2 weeks with 1 week of rest in a 21-day cycle. The primary objective was clinical response rate. Toxicity and pharmacodynamics data were also obtained.

RESULTS

No objective responses were observed. One patient had stable disease, and 11 others experienced disease progression. The median survival time was 4.3 months (range, 0.9-37 months). The most common grade 3 or 4 toxicities included fatigue (58%; n = 7) and skin rash (33%; n = 4). The mean inhibition of specific chymotryptic activity was 53.1% (+/- 13.33%). A statistically significant reduction in the plasma interleukin-6 level was seen (P = 0.0354).

CONCLUSION

Bortezomib was well tolerated but showed limited clinical activity against metastatic breast cancer when used as a single agent. The future development of this agent for the treatment of breast cancer should be guided by in vivo models that optimize activity in combination with other antitumor agents.

Detrusor mitochondrial lipid peroxidation and superoxide dismutase activity in partial bladder outlet obstruction of rabbits

OBJECTIVES

Bladder outlet obstruction has shown to damage detrusor mitochondria with impaired detrusor contractility. One likely cause for mitochondrial injury is reactive oxygen species (ROS)-induced damages, including lipid peroxidation injury. We designed this study to examine this hypothesis.

MATERIALS AND METHODS

Placing a silicon ring around the bladder neck of male New Zealand rabbits induced bladder outlet obstruction. The bladders were removed 3 (N = 6), 7 (N = 6), and 14 days (N = 8) later. Sham operated animals (N = 6 for each time period) served as the controls. Contractile function of the bladder was assessed by the response of the detrusor strips to bethanechol and field stimulation. Detrusor mitochondrial superoxide dismutase (SOD) activity and mitochondrial content of malondialdehyde (MDA) were determined. Detrusor contents of phosphocreatine and adenine triphosphate (ATP) were assayed.

RESULTS

(1) Outlet obstruction induced an increase in the bladder weight and a decrease in the contractile function; (2) mitochondrial SOD activity significantly elevated in every time period of the obstruction, indicating a persistently increased ROS generation; (3) detrusor MDA level increased in 3-day obstruction animals. It returned to the control level in 7- and 14-day groups; (4) phosphocreatine content was significantly reduced in every time period of the obstruction; (5) ATP content was significantly decreased in 3- and 7-day groups; while 14-day obstruction group contained similar level as the sham-operated group.

CONCLUSIONS

This study shows that bladder outlet obstruction increases generation of ROS and enhances lipid peroxidation of detrusor mitochondria. The resulted mitochondrial damages might sustain, leading to persistently depressed energy production and impaired detrusor contractility.

Phase II study of weekly vinorelbine and 24-h infusion of high-dose 5-fluorouracil plus leucovorin as first-line treatment of advanced breast cancer

We prospectively investigated the efficacy and safety of combining weekly vinorelbine (VNB) with weekly 24-h infusion of high-dose 5-fluorouracil (5-FU) and leucovorin (LV) in the treatment of patients with advanced breast cancer (ABC). Vinorelbine 25 mg m⁻² 30-min intravenous infusion, and high-dose 5-FU 2600 mg m⁻² plus LV 300 mg m⁻² 24-h intravenous infusion (HDFL regimen) were given on days 1 and 8 every 3 weeks. Between June 1999 and April 2003, 40 patients with histologically confirmed recurrent or metastatic breast cancer were enrolled with a median age of 49 years (range: 36–68). A total of 25 patients had recurrent ABC, and 15 patients had primary metastatic diseases. The overall response rate for the intent-to-treat group was 70.0% (95% CI: 54–84%) with eight complete responses and 20 partial responses. All 40 patients were evaluated for survival and toxicities. Among a total of 316 cycles of VNB–HDFL given (average: 7.9: range: 4–14 cycles per patient), the main toxicity was Gr3/4 leucopenia and Gr3/4 neutropenia in 57 (18.0%) and 120 (38.0%) cycles, respectively. Gr1/2 infection and Gr1/2 stomatitis were noted in five (1.6%) and 59 (18.7%) cycles, respectively. None of the patients developed Gr3/4 stomatitis or Gr3/4 infection. Gr2/3 and Gr1 hand–foot syndrome was noted in two (5.0%) and 23 (57.5%) patients, respectively. Gr1 sensory neuropathy developed in three patients. The median time to progression was 8.0 months (range: 3–25.5 months), and the median overall survival was 25.0 months with a follow-up of 5.5 to 45+ months. This VNB–HDFL regimen is a highly active yet well-tolerated first-line treatment for ABC.

Non-steroidal anti-inflammatory drug activated gene (NAG-1) expression is closely related to death receptor-4 and -5 induction, which may explain sulindac sulfide induced gastric cancer cell apoptosis

Non-steroidal anti-inflammatory drugs (NSAIDs) are powerful chemopreventive agents in various cancers. They act by inhibiting cyclooxygenase (COX) activity, or through other mechanisms. NSAID-activated gene (NAG-1) has antitumorigenic and pro-apoptotic activities, but the mechanisms of NAG-1-induced apoptosis are poorly understood. Here we examined whether NAG-1 expression is induced in gastric cancer cells treated with NSAIDs, and the effect of NAG-1 expression on cell death. NAG-1 cDNA was transfected into SNU601 cells, and the relation between the ectopic expression of NAG-1 and death receptor-4 (DR-4) and DR-5 levels was studied. We found that NAG-1 expression was strongly induced in SNU601 cells, which lack endogenous COX-2, by sulindac sulfide, and that this was closely related with increased apoptosis and decreased cell viability. Moreover, temporal expressions of DR-4 and DR-5 induced by sulindac sulfide were similar to that of NAG-1. Most SNU601 cells transfected with NAG-1 cDNA did not survive during expansion. Forced NAG-1 expression significantly induced apoptosis and DR-4 and DR-5 expression. We conclude that NAG-1 expression is closely related to DR-4 and DR-5 induction, which could provide a mechanistic basis for the apoptotic effect of COX inhibitors in gastric cancer cells.

Differential effects of carboxyfullerene on MPP+/MPTP-induced neurotoxicity

The effects of carboxyfullerene on a well-known neurotoxin, 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) and its active metabolite 1-methyl-4-phenyl-pyridinium (MPP+) were investigated. In chloral hydrate-anesthetized rats, cytosolic cytochrome c was elevated in the infused substantia nigra 4 h after an intranigral infusion of MPP+. Five days after local application of MPP+, lipid peroxidation (LP) was elevated in the infused substantia nigra. Furthermore, dopamine content and tyrosine hydroxylase (TH)-positive axons were reduced in the ipsilateral striatum. Concomitant intranigral infusion of carboxyfullerene abolished the elevation in cytochrome c and oxidative injuries induced by MPP+. In contrast, systemic application of carboxyfullerene did not prevent neurotoxicity induced by intraperitoneal injection of MPTP. In mice, systemic administration of MPTP induced a dose-dependent depletion in striatal dopamine content. Simultaneous injection of carboxyfullerene (10 mg/kg) actually potentiated MPTP-induced reduction in striatal dopamine content. Furthermore, systemic administration of carboxyfullerene (30 mg/kg) caused death in the MPTP-treated mice. An increase in the striatal MPP+ level and reduction in hepatic P450 level were observed in the carboxyfullerene co-treated mice. These data showed that systemic application of carboxyfullerene appears to potentiate MPTP-induced neurotoxicity while local carboxyfullerene has been suggested as a neuroprotective agent. Furthermore, an increase in striatal MPP+ level may contribute to the potentiation by carboxyfullerene of MPTP-induced neurotoxicity.

Carditis is associated with Helicobacter pylori-induced gastritis and not reflux esophagitis

Pathogenesis of chronic inflammation at the gastric cardia is not yet clear. It is controversial whether cardiac-type mucosa is normal structure at the cardiac region. Therefore, we studied the existence of correlations between carditis, infection, and gastroesophageal reflux disease, and determined the prevalence of cardiac mucosa at the endoscopically defined cardiac region. Gastric biopsy specimens were analyzed from 27 patients with reflux esophagitis and 30 subjects without reflux esophagitis. Carditis was not associated with reflux esophagitis, but with infection. Moreover, the degree of gastritis and atrophy at the cardia were closely related to those of the antrum and body. Cardiac mucosa was not always present in the endoscopically defined cardiac region, and its prevalence was positively correlated with gastritis and atrophy grade of the cardia and age. In conclusion, -induced pangastritis may lead to the development of carditis, which is associated with occurrence of cardiac-type mucosa at the cardiac region.

Interaction between radiation effects, gravity and other environmental factors in Tribolium confusum

Multicellular organisms possess homeostatic control systems, which, in responding to changes of the external environment, modify the internal milieu of the organism accordingly, in order to make survival and normal physiological processes possible. This group has studied effects on physiological processes of single and combined environmental factors in the flour beetle, Tribolium confusum. Studies included low- and high-LET radiation, gravity compensation, near-weightlessness in space flight, ambient temperature, atmospheric composition, and magnetic field effects on the growth and development of Tribolium. For somatic effects, there appears to be a "normal physiological range" for each of these environmental variables; moreover, their effects seem independent of each other. When one of the listed environmental factors is near the limits of normal physiological tolerance, however, marked synergism has been observed between the effects of this factor and other environmental stresses. Fertilized Tribolium eggs showed a differential radiosensitivity to external irradiation, and a linear, dose-effect relationship was obtained, as accelerated heavy nitrogen and oxygen ions were used. Synergism was found when Tribolium were irradiated with ionizing radiation and subsequently exposed to temperature either below or above their normal physiological range. Gravity compensation or near-weightlessness in space flight have adverse effects on the development of Tribolium when an ambient temperature is near the higher or lower limit of tolerance. Similar results were observed when pupae were exposed to a combination of oxygen, temperature and magnetic field stresses.

Biophysical considerations concerning gravity receptors and effectors including experimental studies on Phycomyces blakesleeanus

Part I. Migration and Diffusion of Graviceptors: The physical action of gravitational and inertial forces on graviceptors is considered. The motion of graviceptors as influenced by physical dimensions, density, electric charge, composition of the suspending medium and flow variables is demonstrated. Part II. Observations on Geotropism in Phycomyces blakesleeanus: Mutants of Phycomyces blakesleeanus exhibit strikingly different rates of geotropic response. It is shown that Phycomyces grown in the dark lack normal geotropic responses: pre-exposure to light is necessary for the synthesis of structures responsible for geotropism. A physical model is presented that may account for some of the geotropic phenomena observed in Phycomyces.

Effect of hormone replacement therapy on uterine fibroids in postmenopausal women—a 3-year study

OBJECTIVE

The aim of this prospective 3-year clinical study was to examine the effect of hormone replacement therapy (HRT) on uterine fibroid growth among postmenopausal women.

METHODS

Thirty-seven postmenopausal women with uterine solitary fibroids were recruited randomly for HRT in a 3-year program. All participants received 0.625 mg conjugated equine estrogen (CEE) and 5 mg medroxyprogesterone (MPA) daily. Fibroid volume was measured by transvaginal ultrasonography at baseline and then at 12-month intervals for 3 times. Clinically, significant fibroid growth was defined as an increase in volume of more than 25% compared with baseline. Also, 35 postmenopausal women with uterine fibroid were studied as control who did not receive HRT during the study period.

RESULTS

Fibroid volume had increased significantly after 1 year both in HRT users and non-users. These increases continued to the second year significantly in HRT users but not in non-users. However, the volumes declined significantly at the third year to similar levels as those measured at baseline in control. In HRT users, fibroid volume though significantly increased at the third year (vs. baseline) but declined insignificantly in comparison with the second year. Clinically, at end of the third year study, one of 34 and three of 34 women increased fibroid volume over 25% compared with baseline in HRT non-users and users, respectively.

CONCLUSIONS

HRT does increase uterine fibroid volume statistically. However, its effect appears in the first 2 years of use. The increased fibroid volume begins to decline at the third year both in HRT users and non-users. Clinically, the increased effect of HRT on uterine fibroid of postmenopausal women should be not over-emphasized at least for 3 years of usage.

Reflux esophagitis facilitates low Helicobacter pylori infection rate and gastric inflammation

BACKGROUND

Helicobacter pylori is regarded as an important pathogen in upper gastrointestinal diseases. However, little is known about the relationship between H. pylori infection and reflux esophagitis. Therefore, an investigation was undertaken in Korean subjects regarding the incidence of H. pylori infection, and a histopathological study of reflux esophagitis was also carried out.

METHODS

Analysis of gastric biopsy specimens was conducted for 73 patients with reflux esophagitis and 132 control subjects without reflux esophagitis. The H. pylori infection was assessed by using rapid urease test and the immunohistochemical method, and gastric mucosal morphologic change was analyzed according to the updated Sydney system.

RESULTS

The prevalence of H. pylori infection was significantly lower in patients with reflux esophagitis than in the non-reflux group. Grade of inflammation and glandular atrophy in the antrum and body were higher in patients in the non-reflux group compared with those in the reflux esophagitis group.

CONCLUSIONS

It is suggested that H. pylori infection decreases the risk of reflux esophagitis by inducing atrophic gastritis.

Modulation of calcium balance in tilapia larvae (Oreochromis mossambicus) acclimated to low-calcium environments

This study examined how developing fish larvae regulate their Ca2+ balance for acclimation to low ambient Ca2+. Calcium balance in newly hatched larvae was examined individually. Developing larvae not only increased Ca2+ influx but also decreased Ca2+ efflux when they were acclimated to low-Ca2+ environments. After acclimation for 8 days, the influx and efflux of the low-Ca2+ (0.02 mM) group were about 106% and 43%, respectively, compared to those of the high-Ca2+ (1.0 mM) group. Sensitivity and response to low-Ca2+ environments are age-dependent. Upon acute exposure to low Ca2+. newly hatched (H0) larvae increased both Ca2+ influx (from 24% to 67% of high-Ca2+) and net uptake (from 5% to 69%) within 64 h, while 3-day-posthatching (H3) larvae managed to reach the levels of the control within 38 h. Declining Ca2+ efflux in H3 larvae occurred 14 h after exposure, much faster than those in H0 larvae (38 h). It is suggested that modulation of Ca2+-balance mechanisms in developing larvae is dependent upon the levels of Ca2+ in the larval body.

Gemcitabine and cisplatin in a multimodality treatment for locally advanced non-small cell lung cancer

The role of new cytotoxic agents like gemcitabine has not yet been proven in the neoadjuvant settings. We designed a phase II study to test the feasibility of using gemcitabine and cisplatin before local treatment for stage III non-small cell lung cancer patients. Patients received three cycles of induction chemotherapy of gemcitabine (1000 mg m(-2), days 1, 8, 15) and cisplatin (90 mg m(-2), day 15) every 4 weeks before evaluation for operability. Operable patients underwent radical resection. Inoperable patients and patients who had incomplete resection received concurrent chemoradiotherapy with daily low dose cisplatin. All patients who did not progress after local treatment received three more cycles of adjuvant chemotherapy of gemcitabine and cisplatin. Fifty-two patients received induction treatment. Two patients had complete response and 31 patients had partial response (response rate 63.5%) after induction chemotherapy. Thirty-six patients (69%) were operable. Eighteen patients (35%) had their tumours completely resected. Two patients had pathological complete response. Median overall survival was 19.1 months, projected 1-year survival was 66% and 2-year survival was 34%. Three cycles of gemcitabine and cisplatin is effective and can be used as induction treatment before surgery for locally advanced non-small cell lung cancer patients.

Polyamine depletion induces rapid NF-kappa B activation in IEC-6 cells

The proliferation of the rat intestinal mucosal IEC-6 cell line requires polyamines, whose synthesis is catalyzed by the enzyme ornithine decarboxylase (ODC). ODC inhibition leads to polyamine depletion, as well as inhibition of both cell proliferation and apoptosis by regulating gene expression. The NF-kappa B transcription factor regulates genes involved in apoptotic, immune, and inflammatory responses. In the present study we tested the hypothesis that NF-kappa B is activated following ODC inhibition. We found that the inhibition of ODC by alpha-difluoromethylornithine (DFMO) resulted in a approximately 50% decrease in intracellular putrescine levels within 1 h. NF-kappa B is activated by DFMO through the degradation of the inhibitory protein I kappa B alpha that sequesters NF-kappa B in the cytoplasm. The DFMO-induced NF-kappa B complexes contain the p65 and p50 members of the Rel protein family. DFMO-induced NF-kappa B activation was accompanied by the translocation of p65 from the cytoplasm into the nucleus. DFMO selectively inhibited a gene reporter construct dependent on the kappa B site present in the HLA-B7 gene. In contrast, DFMO had no effect on a gene reporter construct dependent on the kappa B site present in the interleukin-8 gene. Thus, we report that ODC inhibition activates the NF-kappa B transcription factor, which may mediate the altered physiological state of intestinal cells that occurs following polyamine depletion.

The efficacy and safety of risperidone for the treatment of geriatric psychosis

Risperidone is an atypical antipsychotic drug which has been suggested to be beneficial for the treatment of elderly patients with psychotic symptoms. In this study, we assessed the short-term efficacy and the safety of risperidone in geropsychiatric inpatients with psychotic symptoms. The sample population included 110 elderly inpatients with psychotic disorders. Assessment for drug efficacy using the Brief Psychiatric Rating Scale, Sandoz Clinical Assessment-Geriatric scale, and Clinical Global Impression scale was conducted at baseline and also at 4 weeks subsequent to risperidone treatment commencement. Subsequent to commencing risperidone treatment, 80 patients completed a 4-week therapeutic evaluation. Seventy (87.5%) of the 80 patients experienced mild to substantial improvement using the Clinical Global Impression scale. Adverse effects were monitored in all 110 patients. The most commonly detected adverse effects were weakness of legs or walking problems (43/110; 39.1%) and dizziness (32/110; 29.1%). Peripheral edema was noted in 18 (16.4%) patients. Risperidone, in low doses, appeared to have been effective in this sample of patients older than 65 years with psychotic symptoms. The mean dose (2.1 +/- SD 1.4 mg/day) applied was lower then that suggested for young patients and was related to the each specific patient diagnosis. Peripheral edema and walking problems were commonly observed adverse effects for these elderly patients, such problems having not been seen to the same extent in previous studies of young patients.

Characteristics of Chinese suicide attempters admitted to a geropsychiatric unit

PURPOSE

To investigate the characteristics for elderly Chinese suicide attempters in Taiwan and make comparisons with Western reports.

METHODS

During a six-year period, patients admitted to a geropsychiatric unit as a result of a suicide attempt were investigated for factors related to the suicide attempt.

RESULTS

Of the 722 admissions during this period, 55 (7.6%) were patients who had been admitted due to suicide attempt. The sex and age distributions for the suicide attempters were similar to those for other patients. The most common diagnoses were depressive disorders (56.4%), followed by delusional disorders (20.0%). A total of 121 suicide motives were cited for the 55 attempters, an average of 2.2 per person, with depressive symptoms commonly found on admission. During the first week of hospitalization, 53 attempters (96.4%) still exhibited suicidal ideation and six patients made a further suicide attempt, however, only three patients retained suicidal ideation on discharge.

CONCLUSIONS

Our study confirms previous Western reports that depressive disorders are commonly manifested in elderly suicide attempters. There were differences in the motives and methods employed for the suicides, possibly due to cultural difference and/or sample source. Most of the suicide attempters exhibited a favourable response with hospitalization.

Identification of a 70-kDa gastrin-binding protein on DLD-1 human colorectal carcinoma cells

Gastrin17gly acts as a growth factor for the colonic mucosa. Studies of the receptor involved have generally been restricted to its binding properties, and no investigation of the structure of gastrin17gly receptors on human colorectal carcinoma cell lines has yet been reported. The aim of this study was to optimise the conditions for binding of gastrin17gly to the human colorectal carcinoma cell line DLD-1, and to investigate the structure of the receptor responsible. Binding of 125I[Met15]gastrin17gly to DLD-1 cells was measured in competition experiments with increasing concentrations of either gastrin17gly or gastrin17, or with single concentrations of gastrin receptor antagonists. The molecular weights of the gastrin17gly binding proteins were determined by gel electrophoresis and autoradiography after covalent cross-linking of 125I[Nle15]gastrin2,17gly to cells or membranes with disuccinimidyl suberate. The IC50 value for binding of gastrin17gly to DLD-1 cells was 2.1+/-0.4 microM. Binding was inhibited by the non-selective gastrin/cholecystokinin receptor antagonists proglumide and benzotript, but not by the cholecystokinin-A receptor antagonist L364,718, or the gastrin/cholecystokinin-B receptor antagonist L365,260. The molecular weight of the major gastrin binding protein on DLD-1 cells or membranes was 70,000. We conclude that the major gastrin17gly binding site on the human colorectal carcinoma cell line DLD-1 is clearly distinct from the cholecystokinin-A and gastrin/cholecystokinin-B receptors, but is similar in some respects to the gastrin/cholecystokinin-C receptor.

Gemcitabine-induced acute lipodermatosclerosis-like reaction

Gemcitabine is considered to be a well-tolerated and safe cytostatic drug because of the relative lack of side effects. Cutaneous reactions due to gemcitabine treatment, including alopecia and maculopapular eruption, are well known. We report one patient with squamous cell carcinoma of the lung who developed a gemcitabine-induced cutaneous reaction mimicking acute lipodermatosclerosis. This case has never been reported in the literature before.

Assembly of the human signal recognition particle (SRP): overlap of regions required for binding of protein SRP54 and assembly control

Assembly of the human signal recognition particle (SRP) entails the incorporation of protein SRP54, mediated by a protein SRP1 9-induced conformational change in SRP RNA. To localize the region that controls this crucial step in the assembly of human SRP RNA, four chimeras, Ch-1 to Ch-4, composed of portions of human and Methanococcus jannashii SRP RNAs, were generated by PCR site-directed mutagenesis from a larger precursor. Protein-binding activities of the hybrid RNAs were determined using purified human SRP19 and a polypeptide (SRP54M) that corresponded to the methionine-rich domain of human SRP54. Mutant Ch-1 containing the large domain of M. jannashii SRP RNA, as well as mutant Ch-2 RNA in which helices 6 and 8 were replaced, bound SRP54M independently of SRP19. Mutant Ch-3 RNA, which contained M. jannashii helix 6, required SRP19 for binding of SRP54M, but mutant Ch-4 RNA, which possessed M. jannashii helix 8, bound SRP54M without SRP19. We concluded that the formation of a stable ternary complex did not rely on extensive conformational changes that might take place throughout the large domain of SRP, but was controlled by a smaller region encompassing certain RNA residues at positions 177 to 221. Five chimeric RNAs altered within helix 8 were used to investigate the potential role of a significant AA-to-U change and to determine the boundaries of the assembly control region. Reduced protein-binding activities of these chimeras demonstrated a considerable overlap of regions required for SRP54 binding and assembly control.

A MADS box gene from lily (Lilium Longiflorum) is sufficient to generate dominant negative mutation by interacting with PISTILLATA (PI) in Arabidopsis thaliana

Lily MADS box gene 1 (LMADS1), with sequence homology to the AP3 family of genes, was cloned and characterized from lily (Lilium longiflorum). LMADS1 protein contains almost complete consensus sequence of the PISTILLATA (PI)-derived motif (YEFRVQPSQPNLH) found in the AP3 family of genes and paleoAP3 motif (YGSHDLRLA) found in the AP3 family of genes from the low eudicot, magnolid dicot and monocot species. LMADS1 mRNA was expressed in all four whorls of the flower and absent in the vegetative leaves. The LMADS1 protein was only detected in the petals and stamens, indicating that LMADS1 is possibly post-transcriptionally regulated in lily. Arabidopsis plants transformed with 35S::LMADS1 produced flowers with short petals and stamens, however, no floral organ conversion was observed. Ectopic expression of LMADS1 cDNA truncated with the MADS box domain in Arabidopsis generated the ap3-like dominant negative mutation in which the petals were converted into sepal-like structures and the stamens were converted into carpel-like structures. Yeast two-hybrid analysis indicated that LMADS1 truncated with the MADS box domain is able to sufficiently interact with the Arabidopsis PI protein. This result supports that LMADS1 is the functional counterpart of the AP3 gene in lily. Interestingly, in contrast to other B functional genes, LMADS1 truncated with the MADS box domain is able to strongly form homodimers. LMADS1 may represent an ancestral form of the B function gene, which retains the ability to form homodimers in regulating petal and stamen development in lily.

Reversible infra-Hisian atrioventricular block in acute myocarditis

Symptomatic second- or third-degree atrioventricular (AV) block at any anatomical level is a class I indication for permanent pacemaker implantation. We describe a 44-year-old male with acute viral myocarditis who suffered from syncope followed by a seizure attack associated with AV conduction disturbance. His initial electrocardiogram in our emergency room revealed sinus tachycardia with 2:1 AV conduction and a right bundle branch block QRS morphology with a ventricular rate of 60 beats/min. Because of episodic slowing of the heart rate below 40 beats/min, he received 1 mg atropine intravenously which increased the atrial rate but further worsened the AV conduction, resulting in ventricular asystole for more than 30 seconds associated with loss of consciousness and seizure-like activity. He was immediately paced transcutaneously and transferred to the catheterization laboratory to receive temporary transvenous cardiac pacing. The cardiac catheterization study showed a normal coronary angiogram and very mild diffuse hypokinesis. Electrophysiological studies revealed advanced infra-Hisian AV block. The infra-Hisian AV block, however, resolved rapidly in 2 days. The patient did not receive a permanent pacemaker and remained asymptomatic with normal electrocardiogram over 1 year of follow-up. We suggest that symptomatic infra-Hisian AV block due to viral myocarditis can be reversible, and implantation of a permanent pacemaker may not be necessary.

Microcosm enrichment of 1,3-dichloropropene-degrading soil microbial communities in a compost-amended soil

AIMS

A microcosm-enrichment approach was used to investigate bacterial populations that may represent 1,3-dichloropropene (1,3-D)-degrading micro-organisms in compost-amended soil.

METHODS AND RESULTS

After 8 weeks of incubation, with repeated application of 1,3-D, volatilization fluxes were much lower for compost-amended soil (CM) than with the unamended soils, indicating accelerated degradation due to addition of compost, or development of new microbial populations with enhanced degradation capacity. Denaturing gradient gel electrophoresis (DGGE) profiles of the PCR-amplified region of 16S rDNA genes were used to identify dominant bacterial populations in the fumigant-degrading soil. The DGGE results indicated that specific bacterial types had been enriched, and a more diverse fingerprint was observed in the community derived from the compost-amended soil compared with the unamended soil. Fragments from 16 different DGGE bands were cloned, sequenced and compared with published 16S rDNA sequences. Two clones, designated E1 and E4, were unique to all soils to which compost was added, and corresponded to strains of Pseudomonas and Actinomadura, respectively.

CONCLUSIONS

The results show that the addition of compost to soil increases specific microbial populations and results in the accelerated degradation of fumigants.

SIGNIFICANCE AND IMPACT OF THE STUDY

Application of compost manure to soil can help degrade soil fumigants at a faster rate.

Extraction of human DNA for PCR from chewed residues of betel quid using a novel "PVP/CTAB" method

Residues of chewed betel quid (BQ) are often found on crime scenes in Taiwan and possibly some of the Southeast Asian countries. Although these residues are important biological evidences relating to the suspects, the forensic analysis of BQ evidence has been hindered by failures in extraction of human DNA for PCR analysis. Therefore, it is a prerequisite for relevant forensic casework to establish a reliable method for extracting DNA from chewed BQ residues. Three conventional methods (salt/chloroform, 5% Chelex-100 resin, and QIAamp) were first tested for extraction of human DNA from 33 mock BQ samples, which had been stored for less than two months, and 50 four-year-old forensic BQ samples. PCR amplifications from the HLA-DQA1&PM and the STR loci were then used to test the quality of the extracted DNA. For the mock samples, three observations were made. First, PCR amplification of DNA extracted by using these conventional methods had low success rate. Second, the addition of extra Taq DNA polymerase could compensate the lost enzyme activities due to putative inhibitors and, thus, increase the yield. Third, using the Centricon-100 column to remove putative inhibitors substantially improved the efficiency of PCR. However, for the four-year-old forensic BQ samples, none of the attempts for PCR were successful. In order to solve the problem in PCR analysis of DNA from old BQ samples, we developed a DNA extraction method based on the use of polyvinyl pyrrolidone (PVP) and cetyltrimethylammonium bromide (CTAB), which bind to two common classes of PCR inhibitors in plants, polyphenols, and polysaccharides, respectively. The result showed that this "PVP/CTAB" method is completely successful for the mock BQ samples, and 92% (46 out of 50) successful for the four-year-old forensic BQ samples. To our best knowledge, this is the first report of a reliable method for the extraction of human DNA for PCR from chewed BQ residues. This method should provide a useful means for forensic identification in countries where betel chewing is common.