A micropower electrocardiogram amplifier

We introduce an electrocardiogram (EKG) preamplifier with a power consumption of 2.8 muW, 8.1 muVrms input-referred noise, and a common-mode rejection ratio of 90 dB. Compared to previously reported work, this amplifier represents a significant reduction in power with little compromise in signal quality. The improvement in performance may be attributed to many optimizations throughout the design including the use of subthreshold transistor operation to improve noise efficiency, gain-setting capacitors versus resistors, half-rail operation wherever possible, optimal power allocations among amplifier blocks, and the sizing of devices to improve matching and reduce noise. We envision that the micropower amplifier can be used as part of a wireless EKG monitoring system powered by rectified radio-frequency energy or other forms of energy harvesting like body vibration and body heat.

Live Three-Dimensional Transthoracic Echocardiographic Assessment of Transcatheter Closure of Atrial Septal Defect and Patent Foramen Ovale

We report the usefulness of live three-dimensional transthoracic echocardiography in the accurate assessment of the morphology and efficacy of Amplatzer transcatheter devices used for closure of atrial septal defect and patent foramen ovale.

What is the evidence for rechallenging with anthracyclines or taxanes in metastatic breast cancer? A review of the data

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Background: Anthracyclines and taxanes are widely used in the adjuvant setting for high risk, early stage breast cancer. This raises the issue of what is the optimal therapy for those patients who relapse, and what the potential role, if any, there is for rechallenge with these agents. The current evidence base for rechallenging with anthracyclines/anthracediones and taxanes in metastatic breast cancer (MBC) is examined in this study. Methods: Medline/Pubmed database searches were performed upto October 2008 to identify studies in which patients (pts) were rechallenged with anthracyclines/anthracediones or taxanes in MBC. Results: The efficacy data, as well as the safety data relating to neurotoxicity and cardiotoxicity from these studies, are summarized in the Table. Twenty-seven studies were identified (20=anthracycline/anthracedione, 7= taxane) of which only two were prospective studies. Both were small (n= 74 & 51) and related to anthracycline rechallenging. Conclusions: Evidence exists to support rechallenging with anthracyclines and taxanes. However, there are few prospective data on reexposure to taxanes and no data comparing anthracyclines versus taxanes following adjuvant exposure to both agents, supporting the need for clinical trials in this area. Such trials should ideally incorporate a cross-over design at treatment failure, which would shed light on the optimal sequence in which these agents should be administered.

[Table: see text]

No significant financial relationships to disclose.

Genotoxicity of cadmium on root meristem cells of Allium cepa: cytogenetic and Comet assay approach

Cytogenetic and DNA damaging effects of cadmium (Cd) were examined through chromosome aberrations (CA) and Comet assay on the root meristem cells of Allium cepa. Root meristem cells were exposed to Cd (10, 20, and 40 μM) for 24h and also left in water for 24h recovery. Exposure of Cd revealed significant (P<0.001) inhibition of mitotic index (MI), induction of CA, mitotic aberrations (MA), and micronucleus (MN) formation. Similarly, at 40 μM significant increase in the tail length (85.70 ± 9.40 μm) and tail moment (58.75 ± 5.30 μm) was observed as compared to control 4.50 ± 0.76 and 0.86 ± 0.03 μm, respectively. However, cells examined at 24h post-exposure showed concentration-dependent decline in all the endpoints. Findings of this study confirms the root meristem cells of A. cepa are suitable model for detecting both the environmentally induced CA as well as DNA damage analyzed by Comet assay.

Vascular changes and black hole phenomenon after coronary brachytherapy: a pathologically distinct entity

Restenosis remains an important issue even after coronary brachytherapy despite its efficacy in the treatment for in-stent restenosis. The acute and chronic changes in vascular wall are unique following brachytherapy. The restenotic tissue post coronary brachytherapy is relatively acellular and appears echolucent in intravascular ultrasound examination. This is dubbed the "black hole" phenomenon. Despite the similarity in the mode of action of brachytherapy and drug eluting stent implantation, the black hole phenomenon seems to be uncommon after drug-eluting stent implantation except in those patients who have had prior brachytherapy, bare-metal placement and after treatment of saphenous venous graft stenosis. It is possible that not all neointima in stents are created equal. We should propose that neointima be considered primary neointima if it forms after bare metal stenting, secondary neointima if it forms after CBT or DES, and perhaps tertiary if after combined CBT and DES. This type of classification may prove useful for research or clinical purposes. Almost certainly black hole phenomenon results from a modified neointima. However, we do not know whether this is the same restenotic tissue that was present before CBT but just depleted of its cellular element secondary to autolysis or a newly formed tertiary neointima? It is also not clear whether the changes in vascular wall and restenosis are similar after CBT or drug-eluting stent placement. However, there are some unique vascular changes that seem to be common after both of these procedures.

Role of diffusion in excitation energy transfer and migration

Effect of diffusion on excitation energy transfer and migration in a dye pair sodium fluorescein (donor) and Rhodamine-6G (acceptor) has been studied for different viscosities by both steady state and time domain fluorescence spectroscopic measurements. The donor-donor interaction appears to be weaker as compared to donor-acceptor interaction and thus favors direct Forster-type energy transfer. Interestingly, at low viscosity (water in this case) transfer appears to be controlled by material diffusion/energy migration. Further, acceptor dynamics reveals the fact that direct Forster transfer dominates in viscous media.

Use of Tandem Heart as a temporary hemodynamic support option for severe pulmonary artery hypertension complicated by cardiogenic shock

The TandemHeart is a recently-introduced percutaneous ventricular assist device that may be used for short-term hemodynamic support. Its utility has been shown for assisting the left ventricle in a variety of high-risk percutaneous interventions, in helping the left ventricle recover from myocarditis, in cardiomyopathies and in cardiogenic shock following acute coronary syndromes. Limited data exist on its applications in patients with right ventricular failure. We report our experience, possibly the first human case description, of a patient in cardiogenic shock secondary to severe pulmonary artery hypertension where the TandemHeart was used as a short-term hemodynamic support tool.

First human case description of TandemHeart-assisted high-risk percutaneous balloon aortic valvuloplasty using bivalirudin anticoagulation

TandemHeart is a recently-introduced percutaneous left ventricular assist device that can be used for hemodynamic support during high-risk interventional procedures in severely compromised patients. Angioplasty and stent placement in patients with coronary artery disease and high-risk coronary anatomy including the left main coronary artery have been described using this device. We report the first human case description of a high-risk percutaneous balloon aortic valvuloplasty for critical bicuspid aortic stenosis using the TandemHeart for periprocedural hemodynamic support. Also not previously reported is the use of bivaluridin as the periprocedural antithrombin agent during and after high-risk aortic valvuloplasty.

Survival After Disseminated Invasive Aspergillosis in a Multivisceral Transplant Recipient

Disseminated invasive aspergillosis is a serious and potentially lethal infectious complication of immunosuppressed individuals, including transplant recipients. We report here a successfully treated case of disseminated Aspergillus fumigatus infection involving the lungs, brain, and endocardium in a multivisceral transplant recipient. In addition to supportive measures, the patient was aggressively treated with a combination of three antifungal agents, and all immunosuppression was significantly lowered with close observation for rejection. After 3 months of therapy, the patient cleared the fungal infection, made a full recovery of his cerebral function, and was discharged to a rehabilitation facility.

Ileoscopy in 39 hematochezia patients with normal colonoscopy

AIM: To assess the role of retrograde terminal ileoscopy in hematochezia patients with normal colonoscopy.

METHODS: Between January 1997 and March 2005, 39 hematochezia patients (males 36, females 3, mean age 44.7 years) with a reported normal colonoscopy underwent a repeat colonoscopy. After reaching the cecum, attempt was made to localize the ileocecal valve and intubate the terminal ileum. Any abnormality in the mucosa of the terminal ileum was carefully recorded and biopsies were obtained from suspicious-looking lesions.

RESULTS: During the study period there were 39 patients admitted for hematochezia in whom colonoscopy till cecum did not reveal any abnormality. Full-length colonoscopy till the cecum could be performed in all the patients. The terminal ileum could be intubated in 36 patients. No abnormality was noted in 31 patients. Ileal ulcers were noted in two patients. Nodularity along with ulceration of the ileal mucosa, a Dieulafoy’s lesion, and an angiomatous malformation were noted in one patient each. Histological examination of the biopsies obtained from the ulcers revealed typical tuberculous lesion in the patient with nodularity and ulceration. One of the patients had typhoid ulcers and another had non-specific ulcers.

CONCLUSION: Retrograde terminal ileoscopy gives limited but valuable information, in patients with hematochezia and should be attempted in all such patients.

Endoscopic band ligation as salvage therapy in patients with bleeding peptic ulcers not responding to injection therapy

BACKGROUND AND STUDY AIM

Endoscopic band ligation has recently been used to control bleeding from a variety of nonvariceal upper gastrointestinal sources. However, it has not been used as salvage therapy in patients with peptic ulcer in whom injection therapy has failed to control bleeding. The objective was to study the role of band ligation in patients with bleeding peptic ulcer where injection therapy had failed.

PATIENTS AND METHODS

Endoscopic band ligation was attempted in patients with upper gastrointestinal bleeding from peptic ulcers in whom at least two attempts to control bleeding by injection therapy failed. Anti- Helicobacter pylori therapy was given to patients who were infected with the bacteria.

RESULTS

Endoscopic band ligation could be performed in all the 11 patients in whom it was attempted. It was successful in controlling the bleeding in all patients. Over a mean (SD) follow-up of 23.1 (14.8) months none of the patients had recurrence of ulcer or bleeding.

CONCLUSIONS

Endoscopic band ligation is an effective means of controlling bleeding in patients with bleeding peptic ulcer in whom injection therapy is not successful. Band ligation followed by anti- H. pylori therapy is useful in preventing recurrence of ulcer and bleeding in such patients.

Colonic changes in patients with cirrhosis and in patients with extrahepatic portal vein obstruction

BACKGROUND AND STUDY AIMS

Figures for the prevalence of anorectal varices and portal hypertensive colopathy have varied considerably in the available studies of patients with cirrhosis, and few studies have observed these changes in patients with extrahepatic portal vein obstruction (EHPVO). Our aim was to investigate the colonic changes, if any, in patients with EHPVO and to compare them with those seen in patients with cirrhosis of the liver.

PATIENTS AND METHODS

A total of 50 patients with cirrhosis and 35 patients with EHPVO, all of whom had a history of at least one episode of bleeding from esophageal varices, underwent both upper gastrointestinal endoscopy and colonoscopy.

RESULTS

Anorectal varices were seen more commonly in patients with EHPVO than in patients with cirrhosis (63 % vs. 38 %, P < 0.03). Of the patients with anorectal varices, large anorectal varices were also more common in patients with EHPVO than in patients with cirrhosis (73 % vs. 32 %, P < 0.01). Colopathy was noted in 40 % of patients with EHPVO and in 62 % of patients with cirrhosis (P < 0.05). Of the patients with EHPVO, colopathy was noted in 27 % of patients who also had anorectal varices and in 61.5 % of patients without anorectal varices (P < 0.05). Similarly, patients with both cirrhosis and anorectal varices were found to have a lower prevalence of colopathy than cirrhotic patients without anorectal varices (42 % vs. 74 %, P < 0.03).

CONCLUSIONS

Anorectal varices are more common in patients with EHPVO, while portal hypertensive colopathy is more common in patients with cirrhosis. Large anorectal varices are also more common in patients with EHPVO than in patients with cirrhosis and there is an inverse relationship between anorectal varices and colopathy in both cirrhotic patients and patients with EHPVO.

Low grade B cell gastric mucosa associated lymphoma presenting as upper gastrointestinal bleeding from non-healing stomal ulcers

Primary gastric lymphoma is a rare tumour. It is thought that low grade gastric mucosa associated lymphoid tissue lymphoma has not been previously reported to occur in a patient with gastrojejunostomy. This report describes such a case. The patient presented with bleeding from non-healing stomal ulcers. The ulcers healed and there was regression of the tumour after eradication of Helicobacter pylori.

Tuberculous colonic strictures: impact of dilation on diagnosis

BACKGROUND AND STUDY AIM

Colonic strictures are commonly encountered in patients with colonic tuberculosis. If the colonoscope cannot be negotiated past the stricture the procedure is abandoned, the colonic mucosa proximal to the stricture cannot be inspected, and therefore lesions in these locations may be missed.

PATIENTS AND METHODS

130 patients with colonic tuberculosis were studied. Of these 22 (17 %) had impassable colonic strictures. These strictures were dilated, the colonic mucosa proximal to the strictures was then inspected, and biopsies were obtained from lesions of suspicious appearance.

RESULTS

All strictures could be dilated. No abnormality was found in 11 patients. In the other 11 patients one or more additional findings were noted on colonoscopy after dilation. A second stricture was found in three patients. Nodularity and/or ulceration was observed in the colon proximal to the site of the primary stricture in ten patients. Dilation of the strictures and histological examination of the biopsy from target lesions of the proximal colon contributed to making the definitive diagnosis in five patients. The diagnosis was not altered in the remaining six patients.

CONCLUSION

Dilation of colonic strictures facilitates inspection of the colonic mucosa proximal to the strictures, enabling biopsy of target lesions. This approach offers important diagnostic clues and confirmation of the diagnosis in several patients in whom lesions might be missed if strictures are not dilated.

Endoscopic biopsies from normal-appearing terminal ileum and cecum in patients with suspected colonic tuberculosis

BACKGROUND AND STUDY AIMS

Colonic tuberculosis is generally diagnosed by colonoscopy and targeted biopsy of lesions. However, the diagnostic yield of colonic biopsies is not very good. So far as we are aware, there have been no studies investigating the role of biopsies from endoscopically normal-appearing cecum and terminal ileum in diagnosing colonic or ileal tuberculosis, or both.

PATIENTS AND METHODS

Patients with a clinical suspicion of colonic tuberculosis, in whom no endoscopic abnormalities were found on colonoscopy or ileoscopy, were included in the study. Multiple biopsies were obtained from the cecum and ileum.

RESULTS

Fifty patients were studied. Intubation of the terminal ileum was possible in 43 patients (86 %). Histological examination of biopsies obtained from the cecum and terminal ileum showed noncaseating granuloma in two patients. Both of these biopsies were from the terminal ileum. In two other patients, collections of loosely arranged epithelioid cells were observed. This established the diagnosis in these four patients (8 %). In the remaining 46 patients, histology showed nonspecific inflammation in 18 patients (in the cecum in 15 and in the terminal ileum in seven). The other biopsies did not show any abnormalities (33 from the cecum, 34 from the terminal ileum).

CONCLUSIONS

Histological examination of biopsies from the normal-appearing cecum and terminal ileum is useful in a small but significant number of patients with colonic tuberculosis.