Diagnostic yield and optimal duration of continuous-loop event monitoring for the diagnosis of palpitations. A cost-effectiveness analysis

BACKGROUND

Continuous-loop event recorders are widely used for the evaluation of palpitations, but the optimal duration of monitoring is unknown.

OBJECTIVE

To determine the yield, timing, and incremental cost-effectiveness of each week of event monitoring for palpitations.

DESIGN

Prospective cohort study.

PATIENTS

105 consecutive outpatients referred for the placement of a continuous-loop event recorder for the evaluation of palpitations.

MEASUREMENTS

Diagnostic yield, incremental cost, and cost-effectiveness for each week of monitoring.

RESULTS

The diagnostic yield of continuous-loop event recorders was 1.04 diagnoses per patient in week 1, 0.15 diagnoses per patient in week 2, and 0.01 diagnoses per patient in week 3 and beyond. Over time, the cost-effectiveness ratio increased from $98 per new diagnosis in week 1 to $576 per new diagnosis in week 2 and $5832 per new diagnosis in week 3.

CONCLUSIONS

In patients referred for evaluation of palpitations, the diagnostic yield of continuous-loop event recording decreases rapidly after 2 weeks of monitoring. A 2-week monitoring period is reasonably cost-effective for most patients and should be the standard period for continuous-loop event recording for the evaluation of palpitations.

Cloning and expression of a novel gene encoding a new antibacterial peptide from silkworm, Bombyx mori

We differentially screened a novel gene encoding a new antibacterial peptide from the immunized Bombyx mori cDNA library. The gene showed a similar structure to that of cecropin-family, encoding 59 amino acids including a putative leader peptide and mature peptide. The deduced peptide, named Enbocin, had conserved amino acid residues which have been known to play an important role in the antibacterial activities. Enbocin genomic sequence revealed that the transcription unit of Enbocin gene was about 1.2 kb, and the coding sequence was interrupted by an intron of 660 bases. Recombinant Enbocin, expressed under the control of the baculovirus polyhedrin promoter, demonstrated a broad range of antibacterial activities against gram positive and gram negative bacteria.

Double-labeling techniques demonstrate that rod bipolar cells are under GABAergic control in the inner plexiform layer of the rat retina

The synaptic connectivity between rod bipolar cells and GABAergic neurons in the inner plexiform layer (IPL) of the rat retina was studied using two immunocytochemical markers. Rod bipolar cells were stained with an antibody specific for protein kinase C (PKC, alpha isoenzyme), and GABAergic neurons were stained with an antiserum specific for glutamic-acid decarboxylase (GAD). Some amacrine cells were also labeled with the anti-PKC antiserum. All PKC-labeled amacrine cells examined showed GABA immunoreactivity, indicating that PKC-labeled amacrine cells constitute a subpopulation of GABAergic amacrine cells in the rat retina. A total of 150 ribbon synapses established by rod bipolar cells were observed in the IPL. One member of the postsynaptic dyads was always an unlabeled AII amacrine cell process, and the other belonged to an amacrine-cell process showing GAD immunoreactivity. The majority (n=92) (61.3%) of these processes made reciprocal synapses back to the axon terminals of rod bipolar cells. In addition, 78 conventional synapses onto rod bipolar axons were observed, and among them 52 (66.7%) were GAD-immunoreactive. Thus GABA provides the major inhibitory input to rod bipolar cells.

Expression of genes from Rahnella aquatilis that are necessary for mineral phosphate solubilization in Escherichia coli

Rahnella aquatilis is a Gram-negative bacterium that can fix atmospheric nitrogen and also has the ability to solubilize mineral phosphate. We have cloned the genes that confer the mineral phosphate solubilizing (Mps) trait from this organism by mobilizing a cosmid library of R. aquatilis into Escherichia coli HB101. A 7.0-kb EcoRI fragment from a cosmid, when transferred into E. coli strains HB101 and DH5 alpha, conferred the ability to solubilize hydroxyapatite and the production of gluconic acid to E. coli. The relative amounts of soluble phosphate and gluconic acid produced by the cloned 7.0-kb EcoRI fragment in E. coli were significantly higher than those of R. aquatilis. Nucleotide sequence analysis revealed two complete open reading frames (ORF1 and ORF2) and a partial ORF, ORF1 and ORF2 encoded proteins of molecular mass 10 kDa and 44 kDa. The 44-kDa protein showed extensive sequence similarity to pqqE of Erwinia herbicola, Klebsiella pneumoniae and A. Acinetobacter calcoaceticus. The 10-kDa protein revealed strong similarity to the pqqD of K. pneumoniae and A. calcoaceticus.

Topographical relationship of the facial and vestibulocochlear nerves in the subarachnoid space and internal auditory canal

PURPOSE

Our purpose was to investigate the topographical relationship of the facial and vestibulocochlear nerves from the brain stem through the internal auditory canal.

METHODS

We dissected 15 formalin-fixed cadaveric heads and performed MR examinations in 35 healthy subjects in order to examine the topographical relationship of the facial and vestibulocochlear nerves. The cadaveric dissections and the in vivo MR imaging findings were compared indirectly.

RESULTS

The relationship between the facial and vestibulocochlear nerves showed some variation among individuals and according to the location of the nerves within the cisterns or canal. Near the brain stem, 53% of the vestibulocochlear nerves were partially segmented on MR images. The vestibulocochlear nerve was completely divided into separate nerves only in the most lateral portion of the canal, except in three cadaveric dissections, in which separation of the superior vestibular nerve was seen near the brain stem. The facial and cochlear nerves were of similar size on 36% of the MR images. The superior vestibular nerve was larger than the inferior vestibular nerve on 81% of the MR images.

CONCLUSION

The appearance of the facial and vestibulocochlear nerves was variable but followed certain consistent patterns.

Effects of chronic ethanol on the mobilization of arachidonate and docosahexaenoate stimulated by the type 2A serotonin receptor agonist (+/-)-2,5-dimethoxy-4-iodoamphetamine hydrochloride in C6 glioma cells

We studied the effects of chronic ethanol exposure on the mobilization of polyunsaturated fatty acids stimulated by activation of the type 2A serotonin receptor in C6 glioma cells. In our in vitro model, we prelabeled cells with [3H]arachidonate and [14C]docosahexaenonate and subsequently stimulated with the type 2A serotonin receptor agonist (+/-)-2,5-dimethoxy-4-iodoamphetamine hydrochloride. In as early as 10 days of exposure to 20 or 50 mM ethanol, the (+/-)-2,5-dimethoxy-4-iodoamphetamine hydrochloride-simulated mobilization of [3H]arachidonic acid [[3H]AA) and [14C]docosahexaenoic acid ([14C]DHA) was significantly inhibited, and this inhibition was accompanied by decreased mobilization of intracellular [Ca2+]i. Exposure to ethanol did not alter significantly the release of [3H]AA and [14C]DHA stimulated by the calcium ionophore A23187 nor the incorporation of [3H]AA and [14C]DHA into cellular lipids. Decreased mobilization of polyunsaturated fatty acids and calcium in astroglia may contribute to neurotoxicity caused by chronic ethanol exposure.

Isolation of ALU1-P gene encoding a protein with aluminum tolerance activity from Arthrobacter viscosus

We isolated a DNA fragment (ALU1-P) encoding a protein with an activity of aluminum tolerance from an Al tolerant soil microorganism, Arthrobacter viscosus. This microorganism was isolated from acidic tea field soils. The cloned DNA is composed of 1090 nucleotides, which has one open-reading frame without any stop codon. However, when the DNA fragment was transferred into Escherichia coli, a microorganism susceptible to Al toxicity, it endowed E. coli with Al tolerance. The deduced amino acid sequence of the DNA showed 65% identity with the protein of YbaX gene in Escherichia coli, and 51.1% identity with YB91 Haein hypothetical protein of HI1191 gene in Haemophilus influenzae. The ALU1-P gene in the expression vector produced a protein of 192 amino acids deriving a molecular weight of 21.3 kDa by using the stop codon in vector. The ALU1-P gene is a new one that has the characteristic of Al tolerance.

EBV-elicited familial hemophagocytic lymphohistiocytosis

Familial hemophagocytic lymphohistiocytosis (FHL) is a rapidly fatal illness, usually encountered in infancy, characterized by fever, hepatosplenomegaly, pancytopenia, and central nervous system involvement. Microscopic examination of tissue shows a non-malignant lymphohistiocytic infiltrate, with prominent erythrophagocytosis. FHL is an autosomal recessive hereditary disorder but may develop secondarily to other conditions such as immunosuppression, malignancies, fat overload and certain infections. We recently experienced a case of siblings developing FHL, which may be associated with EBV infection.

Determination of esterase-catalyzed cocaine metabolite formation by high-performance liquid chromatography with ultraviolet detection

A reversed-phase high-performance liquid chromatographic (HPLC) method for the determination of cocaine metabolites produced in vitro by serum and liver esterases is described. Hydrolysis of cocaine at the methyl ester bond produces benzoylecgonine and methanol, whereas hydrolysis at the benzoyl ester bond produces ecgonine methyl ester and benzoic acid. This method quantitates benzoic acid (as a measure of ecgonine methyl ester formation) and benzoylecgonine, which can be determined simultaneously and with great sensitivity by HPLC and ultraviolet detection. Cocaine is found to be hydrolyzed to both ecgonine methyl ester and benzoylecgonine; hepatic microsomes exhibit the highest specific activity.

The anticariogenic effect of fluoride in primer, bonding agent, and composite resin in the cavosurface enamel area

The role of fluoride in the prevention of initial caries is well known in dentistry. This study was designed to evaluate the anticariogenic effect of fluoride in primers, bonding agents, composite resins, and glass-ionomer cements in enamel. Twenty-five extracted teeth that had no cracks, white spots, or enamel defects were selected. A 2 x 3 x 1.5 mm cavity was prepared on either the buccal or the lingual surface of each tooth. After pumicing, tooth enamel was etched with 37% phosphoric acid gel for 30 seconds, and the samples were divided into five groups. The samples were primed, bonded, and filled using ART Bond and Brilliant Enamel in group A, OptiBond and Herculite XRV in group B, Syntac and Tetric in group C, Scotchbond Multi-Purpose and Z100 in group D, and a resin-modified glass ionomer (Fuji II LC) in group E. All surfaces except a 2 mm zone adjacent to the cavosurface margin of each sample was protected with nail varnish, and samples were then placed into a buffered solution for 3 days to develop the initial caries. The samples were then sectioned through the restoration faciolingually into wafers that were approximately 300 microns in thickness then thinned to 150 microns. These thin samples were then examined with a polarizing microscope under water imbibition. The fluoride in primer, bonding agent, and composite filling material did not prevent the initial caries in the enamel area adjacent to the restoration, whereas the fluoride in the glass ionomer did prevent the initial-stage caries.

Utility of patient-activated cardiac event recorders in general clinical practice

A retrospective study of 729 consecutive patient-activated continuous loop recorders shows that these devices provide useful diagnostic information about the presence or absence of transient arrhythmias in carefully selected patients with certain specific complaints.

A case of carpal tunnel syndrome due to dialysis-related amyloidosis in a patient undergoing long-term hemodialysis

Carpal tunnel syndrome (CTS) is characterized by burning pain, numbness and tingling sensation in the thumb, index and middle fingers and the lateral half of the palm and progressive atrophy of the thenar muscles by compression of the median nerve within the carpal tunnel due to a variety of etiologic factors. Surgical intervention usually successfully relieves symptoms of CTS. Recently CTS has been regarded as one of the major clinical manifestations of dialysis-related amyloidosis due to beta 2-microglobulin deposition and recognized with increasing frequency in patients undergoing long-term hemodialysis. We report a case of carpal tunnel syndrome due to dialysis-related amyloidosis in patients undergoing long-term hemodialysis, confirmed by electromyography and biopsy in transverse carpal ligament and median nerve.

A case of biliary cystadenocarcinoma

Biliary cystadenocarcinoma is a very rare cystic tumor that arises in the liver or, less frequently, in the extrahepatic biliary system. It has been shown to arise in congenital liver cysts, bile ducts, biliary cystadenoma, in the context of fibropolycystic disease and in the hepatoduodenal ligament. Common presenting symptoms include an abdominal mass, local pain, nausea, jaundice, fever or occasional ascites. Some patients are asymptomatic, the lesion being an incidental finding at autopsy or surgery. Approximately 50 cases have been reported in the literature. We report a case of biliary cystadenocarcinoma in a 63-year-old man with a review of the literature.

Biostatic activity of Coix lacryma seed extract on Toxoplasma gondii in macrophages

Water extract of Coix lacryma seeds (Co-Ex) was separated into several components; dissolved with Tris-Cl buffer and the supernatant (WC1), ammonium sulfate treatment supernatant (WC2) and the pellet (WC3), QAE column chromatography of WC1 and the peak portions; WC4, WC5 and WC6. Murine peritoneal macrophages in DMEM containing 10% heat-inactivated FCS were infected with tachyzoites of Toxoplasma gondii, RH strain, in vitro. By adding modulators such as Co-Ex, WC1,2,3,4,5,6 and LPS or IFN-gamma for 24 hrs, toxoplasmastatic activity of macrophages was examined in relation to nitrite production. Nitrite production of macrophages was enhanced especially in the series of WC2, WC1 and the combination sample (WC1+WC2+WC3) by order, than other components or fractions (WC4, WC5, WC6) tested. Toxoplasmastatic actions such as percentage of the macrophages infected by T. gondii and fold increase of T. gondii in macrophages showed retroverse relations with the amount of nitrite production; i.e., as nitric oxide (NO) increased the phagocytic index of macrophages and the fold increase of tachyzoites in macrophages decreased. Nitrite (NO2) production was increased by adding IFN-gamma in all cases together with enhancement of biostatic effects. Through the results obtained, it is speculated that some components other than the non-proteinous and defatted components in Coix lacryma seeds may contribute to activate macrophages through induction of NO for the biostatic activity.

Cardiomyopathy associated with clozapine

OBJECTIVE

To report a case of symptomatic cardiomyopathy induced during treatment with clozapine, an antipsychotic of the dibenzodiazepine class.

CASE SUMMARY

A patient with a long psychiatric history significant for schizophrenia and no prior cardiac history developed dyspnea, malaise, and edema with a low ventricular ejection fraction during clozapine therapy.

DISCUSSION

The literature concerning cardiorespiratory complications with clozapine therapy is reviewed.

CONCLUSIONS

Cardiorespiratory complications associated with clozapine use are rare. Caution may be warranted in patients treated with other medications, such as benzodiazepines, and in patients with underlying cardiac disease.

Three-dimensional visualization of Salmonella attachment to poultry skin using confocal scanning laser microscopy

The objective of this study was to locate the position of attached or entrapped Salmonella cells in poultry skin. Confocal scanning laser microscopy (CSLM) was used to obtain optical sections of intact poultry skin without artefacts associated with dehydration and other sample preparation techniques. A technique was developed to prevent compression of the poultry skin during CSLM operation. Images of bacteria and poultry skin were obtained after staining with Pyronin-Y. Data indicated that Salmonella cells were mostly located in the cervices and feather follicles. Salmonella in feather follicle floated freely in surrounding liquid even after the skin was thoroughly rinsed.

Control of scarring in adult wounds using antisense transforming growth factor-beta 1 oligodeoxynucleotides

Adult wounds heal with scar formation, whereas fetal wounds heal without scarring and with a lesser inflammatory and cytokine response. We reasoned that a strategy employing antisense oligodeoxynucleotides (ODN) complementary to transforming growth factor (TGF)-beta-1 mRNA might decrease the scarring of dermal wounds in the mouse. To evaluate this concept, we tested the effects of antisense ODN targeted to TGF-beta 1 mRNA by topical application of the ODN on the skin wound. Phosphorothioation of ODN to retard their degradation. When antisense TGF-beta 1 ODN were applied on the wound site, there was marked reduction of scarring compared with a control wound site. This effect of antisense TGF-beta 1 ODN on scar formation was associated with decreased expression of the TGF-B1 gene. However, sense TGF-beta 1 ODN had no effect on the expression of the TGF-beta 1 gene. In addition, control wounds healed with excessive fibrosis compared with the antisense-treated wounds. In conclusion, our results indicate that antisense TGF-beta 1 ODN could be used for ameliorating scar formation during wound healing.

The effect of cimetidine and ranitidine on cognitive function in postoperative cardiac surgical patients

OBJECTIVE

To compare the incidence of delirium in postoperative cardiac surgical patients treated with either cimetidine or ranitidine.

METHOD

Cardiac surgery patients were randomized to receive either cimetidine or ranitidine postoperatively. Each patient underwent three Mini-Mental Status Examinations (MMSE) and the medical record was reviewed for pertinent past medical history, laboratory data, and evidence of delirium on three occasions: one day preoperatively (before H-2 blocker was given), in the early postoperative period (while receiving the H-2 blocker); usually two days postoperatively on the day of hospital discharge (several days after the H2 blocker had been discontinued).

RESULTS

Overall, both groups in the early postoperative period showed a significant decrease in the MMSE score (27.11 +/- 4.44 to 25.38 +/-2.87, mean +/- SD; t = 5.16, p < .0005), which resolved by the time of hospital discharge. There was no significant difference between cimetidine and ranitidine. Both age and preoperative MMSE score were strongly associated with the development of delirium.

CONCLUSIONS

We found no significant difference between cimetidine's versus ranitidine's effect upon cognitive functioning in the postoperative cardiac surgical patient. This was true even when controlling for age and length of stay.

Huge Langerhans cell histiocytosis granuloma of choroid plexus in a child with Hand-Schüller-Christian disease. Case report

In the literature, only two previous cases of presumed Langerhans cell histiocytosis (LCH) granuloma involving choroid plexus have been reported in patients with Hand-Schüller-Christian (HSC) disease, but those cases were not verified by immunohistochemistry or electron microscopy. The authors report a case of LCH granuloma of the choroid plexuses of bilateral lateral ventricles and the fourth ventricle in a child affected by HSC disease. This disease was confirmed by the presence of Birbeck granules on electron microscopy and positive reactivity to S-100 protein. Clinical, radiographic, and histological features are discussed. This case illustrates that LCH granuloma should be considered in the differential diagnosis of intraventricular masses.

[Detection of Toxoplasma antigens and antibodies in mice infected with different strains of Toxoplasma gondii]

This study aims to assess the possible strain-dependent variations in detection of Toxoplasma antigens and antibodies. The virulent RH strain or avirulent Beverley strain of T. gondii were injected into mice, intraperitoneally, and their antigens, antibodies and parasites were identified from the blood or tissues; liver, brain and spleen by ELISA, Western blot and PCR. In mice infected with RH strain, circulating antigens and parasitemia were first detected from 2 days after infection, and Toxoplasma DNA were found in the blood, liver, brain and spleen from 3 days after infection. It was impossible to detect specific IgM and IgG antibodies to T. gondii, and any specific band was not found by Western blot. In mice infected with Beverley strain, circulating antigens were detected between day 10 and day 35. The Toxoplasma DNA was found in the blood and liver from day 15 until day 60, and in the brain from day 20. But Toxoplasma DNA in the spleen were mainly detected between day 10 and day 30. The IgM antibodies were first appeared on day 10 post-infection, and were noted obviously increased between day 15 and 25. The IgG antibodies were first detected on day 15, and showed progressively increased titers. The antibody binding bands were specific according to infection period. Sera from mice infected with Beverley strain reacted mainly with the antigen of 27.5-kDa and 32.5-kDa. In conclusion, mice infected with RH strain revealed Toxoplasma antigens strongly, but not antibodies. However, mice infected with Beverley strain revealed both the Toxoplasma antigens and antibodies. The present results showed that immune responses are different between avirulent and virulent T. gondii.

Microsomal cytochrome P450-mediated liver and brain anandamide metabolism

Anandamide (AN) is an arachidonic acid congener, found in the brain, that binds to the cannabinoid receptor and elicits cannabinoid-like pharmacological activity. Cytochromes P450 (P450s) are known to oxidize arachidonic acid to a wide variety of metabolites, yielding many physiologically potent compounds. To determine if AN could be similarly oxidized by P450s, its metabolism by mouse liver and brain microsomes was examined. Mouse hepatic microsomal incubation of AN with NADPH resulted in the generation of at least 20 metabolites, determined after HPLC separation by increased UV-absorbance at 205 nm. Pretreatment of mice with various P450 inducers resulted in increased hepatic microsomal formation of several AN metabolites, with dexamethasone being the most effective inducer. Phenobarbital pretreatment resulted in a metabolic profile similar to that observed after dexamethasone pretreatment, whereas 3-methylcholanthrene pretreatment selectively increased the formation of several other metabolites. Clofibrate pretreatment had no effect on hepatic AN metabolism. Polyclonal antibodies prepared against mouse hepatic P450 3A inhibited the formation of several AN metabolites by hepatic microsomes from untreated mice as well as the formation of those metabolites found to be increased after dexamethasone pretreatment. AN metabolism by brain microsomes resulted in the formation of two NADPH- and protein-dependent metabolites. Hepatic P450 3A antibody partially inhibited the formation of only one of these metabolites. Thus, P450 3A is a major contributor to AN metabolism in the liver but not in the brain. The physiological consequences of P450-mediated AN metabolism remain to be determined.