Safety and potential cost savings of same-setting electrophysiologic testing and placement of transvenous implantable cardioverter-defibrillators

BACKGROUND

Separately, electrophysiologic study (EPS) and placement of a transvenous implantable cardioverter-defibrillator (ICD) can be performed safely in the majority of patients. The safety and potential cost savings of same-setting procedures have not been evaluated.

HYPOTHESIS

Electrophysiologic study and placement of transvenous ICDs can be performed safely in the same setting at reduced cost.

METHODS

In all. 160 (mean age 65 +/- 10 years, 75% men) and 41 (mean age 66 +/- 11 years, 73% men) consecutive patients who underwent same- versus separate-setting procedures, respectively, were prospectively evaluated.

RESULTS

The two groups had similar clinical characteristics and indications for EPS and ICD therapy. Complications occurred in eight patients (5.0%, 95% confidence interval [CI] 2.3-10.3) who had same-setting procedures (one hypotension during ICD testing, one pocket hematoma, two lead dislodgments, two pneumothoraces, one stroke, and one infection) and in two (4.9%, CI 0.60-16.5) who had separate-setting procedures (one pocket hematoma and one infection). There were no procedure-related deaths or long-term ICD-related complications in either group. The mean time from ICD implantation to hospital discharge was similar in the two groups (2.5 +/- 2.4 vs. 2.7 +/- 2.2 days, p = NS). The combined procedure cost was higher in patients who had separate-setting procedures ($12,403 +/- 1,386 vs. $10,242 +/- 2.256, p = < 0.001). who incurred an additional hospital cost of $2,121 +/- $2,125 for the waiting period (1.7 +/- 1.6 days) between EPS and ICD implantation.

CONCLUSIONS

In patients deemed candidates for ICD therapy based on EPS results, placement of transvenous defibrillators in the same setting as EPS is as safe as separate-setting procedures and, if adopted, could further reduce the cost of providing ICD therapy.

The utility of IS6110 sequence based polymerase chain reaction in comparison to conventional methods in the diagnosis of extra-pulmonary tuberculosis

IS6110 sequence based polymerase chain reaction (PCR) was compared with conventional bacteriological techniques in the laboratory diagnosis of extra-pulmonary tuberculosis (EPTB). One hundred and ninety one non-repeated clinical samples of EPTB and 17 samples from non-tuberculous cases as controls were included. All the samples were processed for Ziehl-Neelsen staining for acid fast bacilli (AFB) and 143 samples were processed by culture for M. tuberculosis . All the samples were processed for PCR amplification with primers targeting 123 bp fragment of insertion element IS6110 of M. tuberculosis complex. Of the total 191 samples processed, 34 (18%) were positive by smear for AFB. Culture for AFB was positive in 31(22%) samples among the 143 samples processed. Either smear or culture for AFB was found positive in 51(27%) samples. Of the total 191 samples processed 120 (63%) were positive by PCR. In 140 samples, wherein both the conventional techniques were found negative, 74 (53%) samples were positive by PCR alone. Among 51 samples positive by conventional techniques, 46 (90%) were found positive by PCR. PCR assay targeting IS6110 is useful in establishing the diagnosis of EPTB, where there is strong clinical suspicion, especially when the conventional techniques are negative.

Computer-aided applications of nanoscale smart materials for biomedical applications

Nanotechnology has the potential to impact the treatment of many diseases that currently plague society: cancer, AIDS, dementia of various kinds and so on. Nanoscale smart materials, such as carbon nanotubes, C60, dendrimers and cyclodextrins, hold great promise for use in the development of better diagnostics, drug delivery and the alteration of biological function. Although experimentation is being used to explore the potential offered by these materials, it is by its very nature expensive in terms of time, resources and expertise. Insight with respect to the behavior of these materials in the presence of biological entities can be obtained much more rapidly by molecular dynamics simulation. Furthermore, the results of simulation may be used to guide experimentation so that it is much more productive than it might be in the absence of such information. The interactions of several nanoscale structures with biological macromolecules can already be probed effectively using molecular dynamics simulation. The results obtained should form the basis for significant new developments in the treatment of disease.

Chemical constituents from Clerodendron serratum

A new compound, serratin, was isolated from the essential oil of Clerodendron serratum along with lupeol. The structure of the compound has been elucidated on the basis of chemical analysis and spectroscopic methods including IR, MS, and NMR techniques.

Ferromagnetic insulating and spin glass behavior in Cr substituted La(0.85)Ag(0.15)MnO(3) compounds

Single phase samples of polycrystalline La(0.85)Ag(0.15)Mn(1-y)Cr(y)O(3) (y = 0, 0.05, 0.10, 0.15, 0.20) were prepared by the solid-state route. These samples were studied by recording x-ray diffraction patterns to investigate their crystal structure, by measuring temperature and frequency variations of ac susceptibility and high temperature magnetization to investigate their magnetic properties and by measuring magneto-resistivity. X-ray diffraction patterns could be refined by using the [Formula: see text] space group. The lattice parameters and Mn-O bond lengths were found to decrease with Cr doping. Paramagnetic to ferromagnetic transitions followed by low temperature spin glass like behavior have been observed from ac susceptibility results. The above transitions could be understood on the basis of double exchange ferromagnetic interaction in Mn(3+)-O(2-)-Mn(4+), super-exchange ferromagnetic interaction in Cr(3+)-O(2-)-Mn(3+) and super-exchange antiferromagnetic interaction in Mn(4+)-O(2-)-Mn(4+) networks. Even though a strong ferromagnetic signal was observed in all the Cr doped samples, no metal-insulator transition has been observed. Thus Cr doping gives rise to a ferromagnetic insulating state and the Cr might take part in super-exchange ferromagnetic interactions. Colossal magneto-resistivity has been observed up to 20% of Cr doping in a wide temperature range down to low temperatures.

Development and characterization of polymeric microspheres for controlled release protein loaded drug delivery system

The aim of the present work was to investigate the preparation of microspheres as potential drug carriers for proteins, intended for controlled release formulation. The hydrophilic bovine serum albumin was chosen as a model protein to be encapsulated within poly(D,L-lactide-co-glycolide) (50:50) microspheres using a w/o/w double emulsion solvent evaporation method. Different parameters influencing the particle size, entrapment efficiency and in vitro release profiles were investigated. The microspheres prepared with different molecular weight and hydrophilicity of poly(D,L-lactide-co-glycolide) polymers were non porous, smooth surfaced and spherical in structure under scanning electron microscope with a mean particle size ranging from 3.98 to 8.74 mum. The protein loading efficiency varied from 40 to 71% of the theoretical amount incorporated. The in vitro release profile of bovine serum albumin from microspheres presented two phases, initial burst release phase due to the protein adsorbed on the microsphere surface, followed by slower and continuous release phase corresponding to the protein entrapped in polymer matrix. The release rate was fairly constant after an initial burst release. Consequently, these microspheres can be proposed as new controlled release protein delivery system.

Thymidine block does not synchronize L1210 mouse leukaemic cells: implications for cell cycle control, cell cycle analysis and whole-culture synchronization

It has been predicted that whole-culture methods of synchronization cannot synchronize cells. We have tested whether thymidine block, one type of whole-culture synchronization, can synchronize L1210 cells. We demonstrate experimentally that the thymidine block method cannot produce a synchronized culture. Although thymidine-treated cells are arrested primarily with an S-phase amount of DNA, there is no narrowing of the cell size distribution and there is no synchronized division pattern following release from the thymidine block. In contrast to a whole-culture synchronization method, cells produced by a selective (i.e. non-whole-culture) method not only have a specific DNA content, but also have a narrow size distribution and divide synchronously. Generalizing the results to other cell lines, we suggest that these conclusions call into question experimental measurements of gene expression during the division cycle based on thymidine inhibition synchronization.

Electron paramagnetic resonance study on manganese doped tetrathioureacopper(I) chloride single crystal

Electron paramagnetic resonance (EPR) spectrum of a NLO material, manganese doped tetrathioureacopper(I) chloride single crystal was investigated at room temperature. The spectra reveal that manganese exists in tetravalent state in the host lattice in interstitial position and the crystal becomes NLO material whereas the pure crystal does not show NLO property. The spin Hamiltonian parameters are evaluated as g=1.9872 and A=157G. The transmission spectrum and the second harmonic generation efficiency confirm that the manganese doped single crystal exhibit NLO property.

A selective approach to histopathology of the gallbladder is justifiable

BACKGROUND

Recent changes in the NHS have led to a considerably increased workload for histopathologists prompting the publication of guidelines from the Royal College of Pathologists regarding specimen analysis. In most hospitals, cholecystectomy specimens are routinely sent for histology regardless of whether or not there is any visible macroscopic abnormality suggestive of malignancy. Our aim was to assess whether it would be safe to adopt a policy of processing only suspicious gallbladders without compromising patient management and outcome.

METHODS

A retrospective analysis of all cholecystectomies performed between 1995 and 1999 was conducted using computerised histopathology records and patient notes. The histopathology department has a standardised procedure for the evaluation of cholecystectomy specimens and all gallbladders had been processed in this manner.

RESULTS

1308 patients had undergone cholecystectomy (mean 262/year). All specimens had been sent for histology: 1249 of the specimens showed chronic cholecystitis, 38 acute cholecystitis or empyema and 16 were removed as part of another procedure. In five gallbladders there was evidence of primary carcinoma. In all cases the gallbladder was opened at the time of surgery (as commented upon in the operation notes) and all showed macroscopic evidence suggestive of carcinoma. Pre-operative ultrasound scanning identified probable carcinoma in three of the five cases.

CONCLUSIONS

All cases of gallbladder carcinoma were diagnosed pre-operatively or intra-operatively and a histological diagnosis did not alter the management or outcome of any of these patients. Selective histopathology of the gallbladder is safe and may be a more measured approach saving histolopathology departments time and money.

Some properties of two families of classes of life distributions

We study the closure properties of the family ℒ(α) of classes of life distributions introduced by Lin (1998) under general compounding. We define a discrete analogue of this family and study some properties.

Neck mestastasis from unknown origin-results of planned primary surgery and post-operative radiation therapy

Ninety-two patients with metastasis of unknown origin were studied between 1986 and 1997 at Kidwai Memorial Institute of Oncology, India. Treatment included planned primary radical neck dissection followed by radiotherapy. Sixty-seven patients completed our multimodal therapy. Thirty-eight of these patients had a median follow-up pf 35.7 months. Nine patients had a median follow-up of 8.3 months. Twenty patients were lost in follow-up after completing the above protocol. Twenty-five patients did not comply with prescribed therapy. Of the followed up patients 78.9% were disease free. The failure rate was 21%, which comprised of regional failure in 16% and liver metastasis in 5%. Primary manifested at base of tongue in 2 patients. In a third world cancer center like ours, advanced neck disease and unreliable follow-up mandate multimodal therapy to be instituted at the first instance. Manifest primaries should be treated on individual basis.

Comparison of event rates and survival in patients with unexplained syncope without documented ventricular tachyarrhythmias versus patients with documented sustained ventricular tachyarrhythmias both treated with implantable cardioverter-defibrillators

Patients with unexplained syncope and inducible ventricular tachyarrhythmias during electrophysiologic testing have an increased cardiac mortality rate. We compared event rates and survival of 178 patients with unexplained syncope and no documented ventricular arrhythmias (syncope group) versus 568 patients with documented sustained ventricular tachycardia (VT or fibrillation (VF) (VT/VF group) treated, as part of a lead (Ventritex TVL) investigation, with similar implantable cardioverter-defibrillators (ICDs) capable of extensive data storage. The 2 groups shared similar clinical characteristics. The mean follow-up was 11 months for the syncope group and 14 months for the VT/VF group. The mean time from device implantation to first appropriate therapy was similar in the 2 groups (109 +/- 140 vs 93 +/- 131 days, p = 0.40). Actuarial probability of appropriate ICD therapy was 49% and 55% at 1 and 2 years, respectively, in syncope group and 49% and 58% in VT/VF group (p = 0.57). Recurrent syncope was associated with ventricular tachyarrhythmias in 85% and 92% of the syncope group and VT/VF group, respectively (p = 0.54). At 2 years, actuarial survival was 91% in the syncope group and 93% in VT/VF group (p = 0.85). We conclude that patients treated with ICD with unexplained syncope and induced VT/VF have an equally high incidence of appropriate ICD therapy and low mortality compared with similar patients with documented VT/VF. These findings, plus the high association between recurrent syncope and ventricular arrhythmias, indicate that VT/VF are likely etiologies in selected patients with unexplained syncope and support ICD therapy in such cases.

Dose-rate effects of ethylene oxide exposure on developmental toxicity

In risk assessment, evaluating a health effect at a duration of exposure that is untested involves assuming that equivalent multiples of concentration (C) and duration (T) of exposure have the same effect. The limitations of this approach (attributed to F. Haber, Zur Geschichte des Gaskrieges [On the history of gas warfare], in Funf Vortrage aus den Jahren 1920-1923 [Five lectures from the years 1920-1923], 1924, Springer, Berlin, pp. 76-92), have been noted in several studies. The study presented in this paper was designed to specifically look at dose-rate (C x T) effects, and it forms an ideal case study to implement statistical models and to examine the statistical issues in risk assessment. Pregnant female C57BL/6J mice were exposed, on gestational day 7, to ethylene oxide (EtO) via inhalation for 1.5, 3, or 6 h at exposures that result in C x T multiples of 2100 or 2700 ppm-h. EtO was selected because of its short half-life, documented developmental toxicity, and relevance to exposures that occur in occupational settings. Concurrent experiments were run with animals exposed to air for similar periods. Statistical analysis using models developed to assess dose-rate effects revealed significant effects with respect to fetal death and resorptions, malformations, crown-to-rump length, and fetal weight. Animals exposed to short, high exposures of EtO on day 7 of gestation were found to have more adverse effects than animals exposed to the same C x T multiple but at longer, lower exposures. The implication for risk assessment is that applying Haber's Law could potentially lead to an underestimation of risk at a shorter duration of exposure and an overestimation of risk at a longer duration of exposure. Further research, toxicological and statistical, are required to understand the mechanism of the dose-rate effects, and how to incorporate the mechanistic information into the risk assessment decision process.

Abnormal estrous cyclicity after disruption of endothelial and inducible nitric oxide synthase in mice

The roles of nitric oxide (NO) and nitric oxide synthase (NOS) in reproduction were studied by examining the estrous cycle of wild-type (WT) mice, inducible NOS (iNOS)-, and endothelial NOS (eNOS)-knockout mice. We observed an average estrous cycle of 4.8 +/- 0.2 days in WT mice. While we observed no significant influence of iNOS deficiency on cycle length, eNOS-knockout females showed a significantly longer estrous cycle (6.6 +/- 0.6 days; p < 0.03) than WT females, due to an extension of diestrus (p < 0.03). There was no influence of iNOS deficiency on ovulation rate compared with that in WT females; however, eNOS-knockout mice showed a significant reduction (p < 0.05) in ovulatory efficiency relative to WT or iNOS-knockout females. In contrast to WT females, in which the highest level of estradiol (E2) was observed at 1500 h of proestrus, iNOS-knockout females reached a peak of E2 at 1830 h of proestrus. In eNOS-knockout females, the peak of E2 occurred at 1830 h, as in iNOS-knockout mice; however, E2 levels were 5-fold and 3-fold higher (p < 0.05) than levels observed in WT and iNOS-knockout females, respectively. There was no effect of genotype on the plasma LH concentrations at proestrus. On the first day of diestrus, eNOS-knockout females showed significantly higher plasma E2 and progesterone levels (p < 0.05) relative to WT and iNOS-knockout females. The dysfunction in cyclicity, ovulation rate, ovarian morphology, and steroidogenesis in eNOS-knockout female mice strongly supports the concept that eNOS/NO plays critical roles in ovulation and follicular development.

Protein Z in healthy human individuals and in patients with a bleeding tendency

Protein Z is a vitamin-K-dependent plasma glycoprotein; its physiological function is not clear. Low protein Z levels were found in patients with otherwise unexplained bleeding disorders. It was therefore suggested that low protein Z levels might be associated with a bleeding diathesis. In the present study we measured protein Z levels in plasma samples of 48 patients with a suspected bleeding disorder and in plasma samples of 200 healthy adult individuals. We found protein Z to have a wide normal range in healthy men and women. Significantly lower protein Z levels were observed in women compared to men, whereas no correlation was found with age or other vitamin-K-dependent coagulation proteins. None of the 48 patients with a bleeding disorder had a protein Z level below the normal range. However, protein Z was significantly lower in the group of male patients with a bleeding history as compared to healthy men. In conclusion, our data indicate that low-normal protein Z levels are not associated with a bleeding tendency. However, it remains to be determined whether a low protein Z level is a weak cofactor associated with an increased bleeding tendency and whether decreased or absent protein Z (conditions not detected in our patients) might constitute a haemorrhagic diathesis.

Cardiac metastasis from carcinoma breast--a case report

Secondary neoplasms of the heart are more common than primary tumours. Metastasis occurs most commonly from bronchogenic carcinoma followed by lymphoma and carcinoma breast. Most often cardiac metastasis go undetected as they are asymptomatic and occurs as a terminal event. A 51 year old lady who developed cardiac metastasis from carcinoma breast diagnosed during life is reported with brief review of the literature.

Relation between impedance and temperature during radiofrequency ablation of accessory pathways

Temperature monitoring is a useful tool for radiofrequency ablation of accessory pathways. Impedance monitoring is also helpful, and an impedance fall of 20 ohm may predict coagulum formation. Therefore the purpose of this study was to prospectively quantitate the correlation between impedance and temperature during radiofrequency ablation. Thirty-three consecutive patients underwent radiofrequency ablation with a thermistor ablation catheter with continuous temperature and impedance monitoring during each energy application. The initial and final impedance and temperature measurements for 319 applications of radiofrequency energy were 109 +/- 17 ohm and 102 +/- 17 ohm (p < 0.0001), respectively, and 37 +/- 1 degree C and 57 degrees +/- 11 degrees C (p < 0.0001), respectively. Among the 319 applications of radiofrequency energy, 158 were associated with > or = 20 degrees C increase in tissue temperature, and 10 were associated with coagulum formation. A > or = 20 degrees C increase in tissue temperature was observed in 84 of 104 applications associated with a 5 to 10 ohm decrease in impedance (81% positive predictive value and 93% negative predictive value). The mean change in impedance for applications associated with and without coagulum formation was -19 +/- 7 ohm and -6 +/- 6 ohm (p < 0.0001), respectively, and coagulum formation never occurred with less than a 12 ohm decrease. In conclusions successful tissue heating without coagulum formation can be achieved by titrating the power to achieve a 5 to 10 ohm decrement in impedance. Impedance decrements beyond 10 ohm increase the likelihood of coagulum formation.

Muscarinic regulation of Alzheimer's disease amyloid precursor protein secretion and amyloid beta-protein production in human neuronal NT2N cells

The Alzheimer amyloid precursor protein (APP) undergoes complex processing resulting in the production of a 4-kDa amyloid peptide (A beta) which has been implicated in the pathogenesis of Alzheimer's disease. Recent studies have shown that cells can secrete carboxyl terminus truncated APP derivatives (APP-S) in response to physiological stimulus. We have used human central nervous system neurons (NT2N) derived from a teratocarcinoma cell line (NT2) to study the signal transduction pathways involved in APP-S secretion and A beta production. Muscarinic receptors (m2 and m3) as well as the heterotrimeric GTP-binding protein Gq and the beta 1 isoform of phospholipase C were present in NT2N neurons. Stimulation of the muscarinic receptor with carbachol resulted in phospholipase C activation as shown by a transient increase in the second messengers 1,2-diacyl-sn-glycerol and inositol 1,4,5-trisphosphate. Carbachol also caused an increase in intracellular Ca2+ levels measured in single NT2N neurons. Under these conditions, carbachol caused a time-dependent 2-fold increase in APP-S secretion into the medium. In contrast, prolonged treatment with carbachol caused a decrease in A beta production into the medium. These results suggest that APP-S secretion and A beta production in NT2N neurons are regulated by the muscarinic/phospholipase C signal transduction pathway. Furthermore, activation of this pathway results in dissociation of APP-S secretion and A beta production.

Ofloxacin-containing combined drug regimens in the treatment of lepromatous leprosy

A total of 26 clinically diagnosed adult patients, with active untreated lepromatous leprosy, with a Bacteriological Index of 4+ or more, were admitted to the hospital of the Central Leprosy Teaching and Research institute, Chengalpattu, India, between 1989 and 1991. After prescribed investigations, the patients were randomly allocated in groups of 3 to 3 treatment regimens, namely: 1, clofazimine 50 mg daily and 300 mg once in 4 weeks + dapsone 100 mg daily (AA); 2, (AA)+ofloxacin 400 mg daily (BB); and 3, (AA)+ofloxacin 800 mg daily (CC). The drugs were administered for 56 days continuously under supervision. Sequential biopsy results on day 0, 7, 14, 28 and 56 in normal mouse footpad revealed no growth by day 28 and 56 in all patients treated with CC and BB regimens, respectively. Calculation of the proportion of viable Mycobacterium leprae through analysis of median infectious dose (ID50) showed significant differences on day 7 in the percentage of kill between the ofloxacin-containing regimens and the other. Moderate to marked clinical improvement has been observed in a significantly higher proportion of patients treated with ofloxacin-containing regimens. All the 3 regimens were well tolerated. No severe complications or side-effects to the drugs were noticed with any of the regimens that required any suspension of treatment or the administration of steroids. Addition of ofloxacin to the standard WHO recommended MDT regimen for multibacillary patients may reduce the present duration of therapy. Ofloxacin may also be considered as an alternative drug in rifampicin-resistant cases or where rifampicin is contraindicated.

Quantitative angioscopy: a novel method of measurement of luminal dimensions during angioscopy with the use of a "lightwire"

PURPOSE

To determine the accuracy and reproducibility of luminal dimension measurements of a newly developed method of quantitative angioscopy.

METHODS

A method was developed for quantitation of luminal dimensions during angioscopy, as variation in magnification with lens-object distance and ambiguity associated with identification of corresponding points about the circumference of a given discrete cross-section render subjective estimates unreliable. A transverse ring of fiberoptically transmitted light was emitted from a guidewire or its housing at a known distance from the distal end of an angioscope and discrete cross-sections of interest were observed as the ring of light was reflected from the luminal surface. Caliper measurement of the diameter of the light ring image (< 50 mW at 488/515 nm), obtained on angioscopic video recordings of cylindrical phantom vessels of known dimensions, was performed by three observers on five occasions.

RESULTS

The mean absolute difference between measured and known luminal diameter (n = 405 observations) was 65 microns +/- 35 microns and the mean coefficient of variation was 4.2%, and the mean difference between measured and known areas (n = 195 observations) was 0.4 mm2, with a mean coefficient of variation of 6.5%.

CONCLUSION

By use of this new lightwire method, luminal dimensions can now be measured in vitro with a high degree of accuracy and reproducibility during angioscopy.