Pharmacological and ablative hybrid therapy of atrial fibrillation

The pharmacological and ablative hybrid therapy of atrial fibrillation (AF) consists of radiofrequency catheter ablation of antiarrhythmic drug-induced typical atrial flutter (AFl) and continuation of drug therapy. The purpose of this study was to determine the effect of this therapy on AF symptoms and quality of life (QoL). Forty-six patients were monitored after isthmus-ablation of drug-induced typical AFl and continuation of their antiarrhythmic drug treatment over a mean follow-up of 22.4+/-11.6 months. AF characteristics, symptoms and QoL before and after ablation were evaluated by the SF-36 question- naire, the Symptoms Checklist-Frequency and Severity Scale and the analysis of ECG recordings. 63% of patients demonstrated recurrences of AF. However, the frequency and duration of symptomatic episodes significantly decreased in 82.6 and 76% of patients. All categories of the SF-36 improved significantly and the AF symptomatology showed a relevant attenuation in 65.8% of the study population.

CONCLUSION

The pharmacological and ablative hybrid therapy significantly reduced the mean number and the duration of symptomatic AF episodes as well as AF-correlated symptoms and was associated with significant QoL improvement.

Influence of obstructive sleep apnea on heart rate turbulence

BACKGROUND

Patients with obstructive sleep apnea (OSA) are at increased risk for cardiovascular disease. Increased sympathetic drive is considered as one of the underlying mechanisms. Both heart rate turbulence (HRT) and heart rate variability (HRV) are parameters to describe autonomic regulation. We investigated the influence of sleep-disordered breathing (SDB) on HRT and HRV in patients with OSA.

METHODS

Sixty-five patients underwent overnight polysomnography for clinically suspected SDB and simultaneous Holter monitoring (11 p.m.-6 a.m.). Patients with diabetes mellitus, a history of cardiac disease, left ventricular dysfunction, periodic breathing pattern, and those on beta-blockers or theophylline were excluded. According to the apnea-hypopnea index (AHI), the patients were assigned to group A (AHI <20, n = 31) or group B (AHI > or =20, n = 34). HRV (time domain, frequency domain) and HRT (onset, slope) were then related to the severity of SDB.

RESULTS

Nighttime turbulence slope (TS) correlated inversely with the AHI (r = -0.45, p = 0.01) and was significantly lower in group B (8.9 +/- 1.6 ms/R-R interval) compared with that in group A (19.8 +/- 4.0 ms/R-R interval, P = 0.01). This relationship remained stable after adjusting TS for the number of ventricular premature contractions. No significant differences in turbulence onset or parameters of nighttime HRV were observed.

CONCLUSIONS

Alterations in nighttime HRT correlate with the severity of SDB, indicating abnormalities in cardiac autonomic activity in moderate-to-severe OSA even in the absence of overt cardiac disease. These changes may be associated with the subsequent development of cardiovascular disease.

[Magnetic resonance imaging of the brain in patients with cardiac pacemakers. Experimental and clinical investigations at 1.5 Tesla]

PURPOSE

In-vitro and In-vivo evaluation of feasibility and safety of MRI of the brain at 1.5 T in patients with implanted pacemakers (PM).

MATERIALS AND METHODS

24 PM models and 45 PM electrodes were tested In-vitro with respect to translational forces, heating of PM leads, behaviour of reed switch (activated vs. deactivated) and function at a 1.5 T MRI-system (actively shielded, maximum field gradient: 30 mT/m; rise time: 150 T/m/s). Based on these results, 63 MRI examinations in 45 patients with implanted PM were performed. Prior to MRI the PM were re-programmed in an asynchronous mode. The maximum SAR of MRI-sequences was limited to 1.2 W/kg. Continuous monitoring of ECG and pulse oximetry was performed during MRI. PM inquiry was performed prior to MRI, immediately after MRI and -- to assess long-term damages -- three months after the MRI exams, including determination of stimulation thresholds to assess potential thermal myocardial injuries at the lead tips.

RESULTS

Translational forces (F (max) < or = 560 mN) and temperature increase (DeltaT (max) < or = 2.98 degrees C) were in a range which does not represent a safety concern from a biophysical point of view. No changes to the programmed parameters of the PM or damage of PM components were observed neither In-vitro (n = 0/24) nor In-vivo (n = 0/63). Despite the strong magnetic field, the reed switch remained deactivated in 54 % (13/24) of the cases during In-vitro simulated MRI exams of the brain. All patient studies (n = 63/63) could be completed without any complications. Atrial and ventricular stimulation thresholds (expressed as pulse duration at 2-fold rheobase) did not change significantly immediately post-MRI nor in the 3 months follow-up (pre-MRI: 0.17 ms +/- 0.13 ms, post-MRI: 0.18 ms +/- 0.14 ms, 3 months follow-up: 0.17 ms +/- 0.12 ms).

CONCLUSION

MRI of the brain at 1.5 Tesla can be safely performed in carefully selected clinical circumstances when appropriate strategies are used (re-programming the PM to an asynchronous mode, continuous monitoring of ECG and pulse oximetry, limiting the SAR value of the MRI sequences, cardiological stand-by). Based on these studies, implanted PM should not longer be regarded as an absolute contraindication for MRI at 1.5 T.

Atrial fibrillation: profit from cardiac pacing?

The impact of cardiac pacing on the prevention of atrial fibrillation is under scientific investigation. Several prospective randomised clinical trials have reported that atrial-based "physiologic" AAI(R)- or DDD(R)-pacing is associated with a lower incidence of paroxysmal and permanent atrial fibrillation than single-chamber ventricular pacing in patients with a conventional pacemaker indication. However, it is still uncertain whether atrial pacing itself has independent antiarrhythmic properties. In contrast, right ventricular pacing is considered to promote atrial fibrillation, even in preserved AV synchrony during dual-chamber pacing. The electrical secondary prevention of atrial fibrillation is mainly based on variations of the atrial pacing site and sophisticated preventive pacing algorithms incorporated in the pacemaker software. Dual-site right atrial and biatrial pacing were reported to exhibit modest to no benefit for the prevention of atrial fibrillation, whereas septal pacing and specific preventive pacing algorithms have been demonstrated to reduce the incidence of atrial fibrillation in a number of clinical trials. However, the role of septal pacing and preventive pacing algorithms still has to be clarified since, overall, study results have been inconsistent so far. One of the main goals of future investigations should be the identification of responder groups of preventive pacing concepts. In clinical practice, the efficacy of pacing algorithms and septal pacing has to be determined in the individual case. These options should be taken into account in patients with symptomatic bradycardia as the indication for cardiac pacing and, in addition, symptomatic atrial fibrillation.

3D Motion Adapted Gating: Eine neue Navigatortechnik zur Verkürzung der Messzeit bei der MR-Koronarangiographie

PURPOSE

A major problem of free breathing coronary MR angiography (MRA) with respiratory navigator gating is low navigator efficiency and prolonged scan time due to irregular breathing patterns. 3D motion adapted gating (MAG) is a new adaptive navigator technique, which adapts in real time to changes of the end-expiratory position of diaphragm. This study evaluates the influence of 3D MAG on coronary MRA.

METHODS AND MATERIALS

In 3D MAG, two additional gating windows are grouped around the conventional window. Additionally, each gating window is divided into three bands assigned to different portions of the k-space. The scan is terminated when three consecutive bands are filled and one complete image data set is collected. Free breathing navigator-gated coronary MRA was performed on 48 patients with suspected coronary artery disease. In random order, each patient underwent an ECG-gated, a 3D segmented k-space gradient echo sequence using 3D MAG and a conventional navigator technique. The coronary MRA was evaluated and compared using the following parameters: 1. navigator efficiency and scan time; 2. visualized coronary artery length; 3. qualitative assessment of image quality; and 4. detection of stenoses > 50 % in comparison with catheter angiography.

RESULTS

Coronary MRA with 3D MAG had a significant increase in the average navigator efficiency (46 % +/- 12 % vs. 38 % +/- 12 %, p < 0.05), resulting in a significantly shorter scan time (mean: 18 % +/- 4 %, p < 0.05) for coronary MRA with 3D MAG compared to conventional navigator technique. Scans with and without 3D MAG had no significant differences in the continuously visualized vessel lengths, in the assessed image quality and in the sensitivity and specificity (83 % and 89 % vs. 83 % and 88 %, p > 0.05) of detecting coronary artery stenoses > 50 %.

CONCLUSION

The 3D MAG technique improves the navigator efficiency and significantly (p < 0.05) shortens the scan time of navigator gated coronary MRA while maintaining image quality and diagnostic accuracy in the detection of coronary artery stenoses.

Amiodarone-associated "torsade de pointes". Relevance of concomitant cardiovascular medication in a patient with atrial fibrillation and structural heart disease

A 69 year old female with history of coronary heart disease, myocardial infarction and paroxysmal atrial fibrillation suffered from occipital apoplexy. Under treatment with amiodarone 600 mg daily and concomitant medication with beta-acetyldigoxine (0.1 mg daily) and bisoprolole (1.25 mg daily), significant QT-prolongation (max. 700 ms; QTc: 614 ms) could be documented. Out of normofrequent sinus rhythm but as well out of bradycardia, the patient developed repetitive short-lasting "torsade de pointes" tachycardias (320 bpm) which terminated spontaneously. Serum electrolytes, plasma levels of digoxine (1.76 ng/ml) and amiodarone (1.9 mcg/ml) were within therapeutic range. This case report is the first to describe induction of amiodarone-associated "torsade de pointes" tachycardia during concomitant beta-blocker and digitalis medication in a patient with atrial fibrillation and structural heart disease. This points towards an elevated risk for proarrhythmia under this triple therapy.

Heart rate variability in patients suffering from structural heart disease and decreased AV-nodal conduction capacity

METHODS

Time and frequency domain analysis were conducted during a period of 600 s each. We performed a special protocol consisting of five different "pacing" periods: 1) recording of normal sinus rhythm (SR1); 2) atrial pacing with a rate 15% higher than the intrinsic heart rate; 3) ventricular pacing triggered by atrial activation (VAT, with a short AV-delay of 80 ms); 4) AV-sequential pacing with an atrial rate 15% higher than the intrinsic heart rate and a very short AV delay of 80 ms (DDD); 5) normal sinus rhythm (SR2). Only patients with normal AV-nodal conduction or with AV-block I degrees were included. The influence of a structural heart disease as well as a non-sustained VT on Holter ECG and a depressed EF on HRV parameters were analyzed using a multivariate analysis. All patients were lying in a supine position. Blood pressure was measured continuously and the frequency of breathing was controlled.

RESULTS

No differences in HRV between the two sinus rhythm periods SR1 versus SR2 could be detected. Neither SR1 vs VAT showed a significant difference for SDNN and r-MSSD. In contrast, HRV during SR1 compared to AAI, and HRV during VAT compared to AAI were significantly different (p < 0.001). When comparing HRV during DDD, which should be zero, and AAI, we found a significantly lower SDNN and r-MSSD (1.2 ms vs 4 ms, p < 0.04). The presence of structural heart disease, a non-sustained ventricular tachycardia, a depressed ejection fraction of less than 0.50 did not reveal a significant influence on the HRV parameters (multivariate analysis). The mean Wenckebach in patients with structural heart disease tended to be greater (437 ms vs 350 ms, p = 0.05); an increase in the Wenckebach was not correlated to a change in HRV parameters (p = ns).

CONCLUSION

Heart rate variability derived from consecutive RR-intervals is predominantly caused by periodicity in sinus-node impulse formation. A conduction variability of the AV-node exists, but is very low. The presence of a structural heart disease, a non-sustained ventricular tachycardia on Holter ECG, as well as a depressed ejection fraction of less than 0.50 showed no significant influence on the HRV parameters. Therefore, one can apply the calculation of heart rate variability for risk stratification in patients suffering from structural heart disease and moderate AV-nodal conduction disturbances. Attenuation of the oscillation of the heart rate, i. e. heart rate variability (HRV), is associated with an increased risk for mortality in patients with structural heart disease. Many of these patients also suffer from conduction disturbances, e. g. AV-nodal conduction delays. Whether the calculation of HRV in those patients is recommendable has not been investigated yet. Therefore, we conducted a study consisting of 20 consecutive patients in order to determine the formation of HRV, the influence of structural heart disease, the presence of a nonsustained ventricular tachycardia (VT), and a reduced ejection fraction (EF) on the HRV parameters during an elective electrophysiologic study.

In vitro cytotoxicity testing with fluorescence-based assays in cultured human lung and dermal cells

An in vitro study using human cultured cells was conducted to determine the reliability of fluorescence-based cell viability indicators with traditional in vitro cytotoxicity testing methods. Human lung epithelial carcinoma (A549) cells, and human embryonic skin (WS1) and lung (HFLI) fibroblasts were studied in culture to evaluate their potential to screen for cytotoxicity and to compare to previous protocols conducted in our laboratory. Confluent monolayers were incubated in the absence or presence of increasing concentrations of test chemicals for 24 h, and fluorescent-labeled probes were used to assess toxicity. Eight chemicals, including mercuric chloride, copper sulfate, sodium fluoride, thioridazine HCl, paraquat, amitriptyline-HCl, verapamil-HCl and chloroquine sulfate, were tested with each cell line using calcein-AM and Sytox. The data suggest that fluorescent probes are sensitive indicators of cytotoxicity and contribute to understanding the mechanisms for each chemical. In combination with previously published reports, the similarity of results among cell lines may be explained by the origin of the cell lines rather than by the diversity of the methods and indicators employed.

[Cardiac resynchronization therapy by biventricular pacing. How many patients with left ventricular dysfunction are eligible?]

BACKGROUND AND OBJECTIVE

Cardiac resynchronization therapy by multisite biventricular pacing presents an additive therapeutic option in the treatment of severe congestive heart failure. The objective of the study was to evaluate how many patients with left ventricular dysfunction may potentially benefit from this therapy.

METHODS

A total of 975 patients were screened for the prevalence of left ventricular dysfunction. Patients with a left ventricular ejection fraction (LVEF) <45 % were included into the investigation. Potential benefit of biventricular pacing was presumed in the presence of: LVEF < 35 %, severe heart failure (NHYA class III or IV), intrinsic left bundle branch block pattern with QRS interval > 150 ms and the absence of atrial fibrillation in the last 3 months before study inclusion.

RESULTS

In 203 patients (168 male, 35 female, mean age: 64 +/- 11) an LVEF <45 % was found. A total of 12 of these patients (6 %) or 12 of 113 patients (11 %) with an LVEF <35 % were identified as appropiate candidates for biventricular resynchronization therapy.

CONCLUSIONS

Cardiac biventricular pacing currently serves as a therapeutic option for a relatively small subgroup of patients with left ventricular dysfunction. Focusing on estimations that the incidence of heart failure in Germany amounts to more than 100.000 cases per year our results suggest that after all more than 6.000 patients per year may potentially benefit from electric resynchronization therapy. This number may increase substantially if prospective studies can prove that patients with heart failure and atrial fibrillation or left ventricular conduction delay due to univentricular pacing also benefit from cardiac resynchronization therapy.

Decremental intravenous pulse propagation during extrastimulus pacing: relevance for catheter ablation of focal atrial fibrillation

We report a case study demonstrating delayed circumferential intrapulmonary-venous conduction characteristics during coronary sinus extrastimulus pacing. This phenomenon allowed the unmasking and discrimination of a localized left atrial to PV breakthrough from secondarily activated PV muscle in a common left-sided PV ostium. Thus, this pacing manoeuvre may serve to guide RF delivery in the treatment of focal AF.

Stress incontinence observed with real time sonography and dynamic fastscan magnetic resonance imaging--insights into pathophysiology

Our concepts of pathophysiology of stress urinary continence have been greatly shaped by developments in radiographic imaging. Simple radiographs with and without contrast initially revealed the importance of urethral descent in pathogenesis. More recently, magnetic resonance imaging (MRI) and real time ultrasonography are showing soft tissue detail within both a global pelvic and a local urethral context. Careful examination of these studies can extend our concepts of pathophysiology and lead us beyond existing paradigms. We propose a unified theory of stress incontinence based on our dynamic fastscan MRI and real time ultrasonograms of stress incontinence, incorporating known details of pelvic anatomy, sphincteric location and function. The hypothesis introduces the concept of a continence threshold at which the urethra is subjected simultaneously to both shearing and explusive forces. If these forces are sufficient to overcome urethral coaptation at threshold, leakage results. The model proposes an anatomical sequence of changes through which the incontinent urethra cycles between periods of rest and increased abdominal pressure, and suggests a way in which repeated episodes of prolpase and urethral traction by shearing forces exerted by the vagina on the urethra may contribute to the development of intrinsic sphincteric deficiency.

Subacute cytotoxicity testing with cultured human lung cells

This study was designed to evaluate the potential of an in vitro cell culture method for its ability to determine subacute cytotoxicity and to compare the cytotoxic concentrations with rodent LD(50)s and clinical human toxicity data. Human fetal lung fibroblasts (HFL1) were incubated in the absence or presence of increasing concentrations of test chemicals for 72 h, and cell proliferation was used as a marker for toxicity. Inhibitory concentrations were extrapolated from concentration-effect curves after linear regression analysis. Comparison of the cytotoxicity data from testing 50 chemicals, with available human lethal concentrations for the same chemicals, revealed that the 72-h experimental IC(50)s are as accurate predictors of human toxicity as equivalent toxic blood concentrations derived from rodent LD(50)s. In addition, our results demonstrate that subacute 72-h exposure of HFL1 cells more accurately predicts cytotoxicity than a 24-h mitochondrial assay previously conducted in our laboratory, although the experimental IC(50) values were not statistically different in the two assays. It is anticipated that this procedure, together with a related battery of tests, may supplement or replace currently used animal protocols to screen chemicals for human risk assessment.

Expression of p53-related protein p63 in the gastrointestinal tract and in esophageal metaplastic and neoplastic disorders

p63 is a p53-related DNA-binding protein that helps regulate differentiation and proliferation in epithelial progenitor cells. Its expression has never been evaluated in the human gastrointestinal tract. The aim of this study was to evaluate the expression of p63 in the esophagus and related metaplastic and neoplastic disorders to gain insight into the pathogenesis of these processes. Of particular interest was the expression of p63 in Barrett esophagus (BE) and in BE-associated multilayered epithelium. Multilayered epithelium has been postulated to represent an early precursor to the development of BE primarily because it shares morphologic and immunophenotypic features of both squamous and columnar epithelium, and has been shown prospectively to be highly associated with BE. Routinely processed mucosal biopsy or resection specimens that contained normal esophageal squamous epithelium (n = 20), squamous dysplasia (n = 4), squamous cell carcinoma (n = 7), BE (n = 10), BE-associated multilayered epithelium (n = 13), esophageal mucosal gland ducts (n = 10), BE-associated dysplasia (n = 12), and BE-associated adenocarcinoma (n = 7) were immunostained for p63 to determine the extent and location of staining. p63 staining was compared with the staining patterns observed for p53, Ki 67 (proliferation marker), and cytokeratins (CKs) 13 (squamous marker), 14 (basal squamous marker), 8/18 (columnar marker), and 19 (basal/columnar marker). Expression of p63 messenger RNA (mRNA) isoforms was also analyzed by reverse-transcription polymerase chain reaction of freshly isolated tissues. In the normal esophagus, p63 was expressed in the basal and suprabasal layers of the squamous epithelium and in basal cells that line the mucosal gland ducts but was negative in all other epithelia of the gastrointestinal tract, including the stomach, small intestine, and colon. Similarly, p63 was not expressed in BE, but it, was present in the basal layer of multilayered epithelium in 9 of 13 cases (69%). p63-positive cells in multilayered epithelium and in the mucosal gland duct epithelium were positive for CK8/18 (100%) and CK13 (67% and 30%, respectively) and negative for CK14 (0%), in contrast to p63-positive cells in squamous epithelium, which were positive for CK14 and CK13 (100%) but negative for CK8/18. In neoplastic tissues, p63 was diffusely expressed in all cases of esophageal squamous cell dysplasia and carcinoma but was negative in all cases of esophageal and colorectal adenocarcinoma. The DeltaN isoform of p63 mRNA predominated in all benign and neoplastic squamous tissues examined. p63 may represent a marker of 2 distinct epithelial progenitor cells (basal squamous epithelium and gland duct epithelium) in the esophagus. P63 is upregulated in squamous neoplastic conditions and in this manner may play a role in squamous carcinogenesis. These data also indicate that multilayered epithelium is phenotypically similar to, and may share a lineage relationship with, mucosal gland duct epithelium.

[Surgery of substernal goiter]

OBJECTIVE

To study the surgical approaches and operative techniques for substernal goiter.

METHOD

A retrospective study of 27 cases with substernal thyroid nodules was made in our hospital.

RESULT

The operations on 27 patients with substernal nodules have been successfully carried out. Among them, 10 were goiters, 9 adenomas, 4 malignancy and 4 were thyroid cancer metastasizing to paratracheal or substernal nodes. Resection via cervical collar incision was adequate in 23 cases. Three thyroid cancers with paratracheal node metastasis were completely resected by sternotomy and only one thyroid cancer with paratracheal and substernal nodes metastasis was resected by combined thoracotomy and cervical collar incision.

CONCLUSION

Resection via cervical collar incision for all retrosternal thyroid nodules were advised. The preliminary experience with this procedure suggests that it has some advantages in the management of substernal goiter, including: 1. ease of operation compared to both sternotomy and thoracotomy; 2. relatively low morbidity; 3. safe and reliable.

In vitro and in vivo evaluations of biodegradable implants for hormone replacement therapy: effect of system design and PK-PD relationship

This investigation evaluated the feasibility of using subdermally implantable devices fabricated by nonconventional 3-dimensional printing technology for controlled delivery of ethinyl estradiol (EE2). In vitro release kinetics of EE2 and in vivo pharmacokinetics/pharmacodynamics in ovariectomized New Zealand White rabbits were carried out to study 3 implant prototypes: implant I (single-channel EE2 distribution in polycaprolactone polymer core), implant II (homogeneous EE2 distribution in polycaprolactone polymer matrix), and implant III (concentration-gradient EE2 distribution in polycaprolactone and poly(dl-lactide-co-glycolide) (50:50 matrix). EE2 was found to be released from all the implants in a nonlinear pattern with an order of implant III > implant II > implant I. The noncompartmental pharmacokinetic analysis of plasma EE2 profiles in rabbits indicated a significant difference (p < .05) in Cmax, tmax, and mean residence time between implant I and implants II and III, but no difference in the area under the plasma concentration time curves calculated by trapezoidal rule (AUC) among the implants. For pharmacodynamic studies, endogenous follicle-stimulating hormone (FSH) and luteinizing hormone (LH) levels were observed to be suppressed following implantation of all implants, which demonstrated that a therapeutically effective dose of EE2 had been delivered. Furthermore, the noncompartmental analysis of plasma FSH and LH profiles in rabbits showed a significant difference (p < .05) in AUC and the mean residence time between implant III and implants I and II. A good in vivo/in vitro relationship was observed between daily amounts of EE2 released and plasma profiles of EE2 for all implants. This relationship suggests that plasma profiles of EE2 could be predicted from in vitro measurement of daily amount of EE2 released. Therefore, performing in vitro drug release studies may aid in the development of an EE2 implant with the desired in vivo release rate.

Histologic and immunophenotypic classification of cervical carcinomas by expression of the p53 homologue p63: a study of 250 cases

Recent studies of the p53 homologue p63 indicate that this gene is preferentially expressed in basal and immature cervical squamous epithelium. This study correlated p63 expression with morphologic phenotype and human papillomavirus (HPV) type in a wide range of cervical neoplasms. Two hundred fifty cases of cervical carcinoma, including squamous cell carcinoma (SCCA; n = 178), adenocarcinoma (ADCA; n = 28), adenosquamous carcinoma (ASCA; n = 8), neuroendocrine carcinoma (NECA; n = 15), and other variant or mixed types (n = 21) were studied. Ninety-seven percent of SCCA, 0% of ADCA, and 0% of SCUC showed strong (>75% v <30%) positivity for p63 (P<.001). p63 sharply distinguished SCCA (p63+) from ADCA (p63-), Large-cell, poorly differentiated carcinomas were distinguished as putative glandular (glassy cell) or squamous (lymphoepithelial-like or spindle cell) types based on p63 staining. Eight (73%) of 11 neuroendocrine tumors tested were chromogranin positive; all showed no or low (<30%) levels of p63 immunostaining. Absence of p63 was also associated with a subset of nonneuroendocrine undifferentiated carcinomas. Transitions from squamous to columnar or undifferentiated morphology coincided with loss of p63 expression. A strong association between HPV 16 and p63 positivity was identified because of the colocalization of both within tumors of squamous phenotype. p63 is a powerful marker for squamous differentiation and, when diffusely expressed, excludes a glandular or neuroendocrine differentiation. p63 may be useful for differentiating pure squamous or glandular from adenosquamous carcinomas, tracking shifts in differentiation within tumors, supporting (by its absence) the diagnosis of neuroendocrine carcinomas, and clarifying the spectrum of poorly differentiated carcinomas lacking either squamous or neuroendocrine differentiation.

Hay-Wells syndrome is caused by heterozygous missense mutations in the SAM domain of p63

Hay-Wells syndrome, also known as ankyloblepharon-ectodermal dysplasia-clefting (AEC) syndrome (OMIM 106260), is a rare autosomal dominant disorder characterized by congenital ectodermal dysplasia, including alopecia, scalp infections, dystrophic nails, hypodontia, ankyloblepharon and cleft lip and/or cleft palate. This constellation of clinical signs is unique, but some overlap can be recognized with other ectodermal dysplasia syndromes, for example ectrodactyly--ectodermal dysplasia--cleft lip/palate (EEC; OMIM 604292), limb--mammary syndrome (LMS; OMIM 603543), acro-dermato-ungual-lacrimal-tooth syndrome (ADULT; OMIM 103285) and recessive cleft lip/palate--ectodermal dysplasia (CLPED1; OMIM 225060). We have recently demonstrated that heterozygous mutations in the p63 gene are the major cause of EEC syndrome. Linkage studies suggest that the related LMS and ADULT syndromes are also caused by mutations in the p63 gene. Thus, it appears that p63 gene mutations have highly pleiotropic effects. We have analysed p63 in AEC syndrome patients and identified missense mutations in eight families. All mutations give rise to amino acid substitutions in the sterile alpha motif (SAM) domain, and are predicted to affect protein--protein interactions. In contrast, the vast majority of the mutations found in EEC syndrome are amino acid substitutions in the DNA-binding domain. Thus, a clear genotype--phenotype correlation can be recognized for EEC and AEC syndromes.

Biomechanical modeling of penetrating traumatic head injuries: a finite element approach

Due to advances in emergency medical care and modern techniques, treatment of gunshot wounds to the brain have improved and saved many lives. These advances were largely achieved using retrospective analysis of patients with recommendations for treatment. Biomechanical quantification of intracranial deformation/stress distribution associated with the type of weapon (e.g., projectile geometry) will advance clinical understanding of the mechanics of penetrating trauma. The present study was designed to delineate the biomechanical behavior of the human head under penetrating impact of two different projectile geometry using a nonlinear, three-dimensional finite element model. The human head model included the skull and brain. The qualitative comparison of the model output with each type of projectile during various time steps indicated that the deformation/stress progressed as the projectile penetrated the tissues. There is also a distinct difference in the patterns of displacement for each type of projectile. This observation matches our previous study using a physical gelatin model of delineate the penetrating wound profiles for different projectile types. The present study is a first step in the study of biomechanical modeling of penetrating traumatic brain injuries.

Expression of the p53 homologue p63 in early cervical neoplasia

BACKGROUND

p63, a homologue of the tumor suppressor gene p53, is expressed in embryonic, adult murine, and human basal squamous epithelium and encodes both transactivating and dominant negative transcript isoforms. Mouse embryos functionally deficient in p63 fail to replenish basal squamous epithelial cells, resulting in multiple defects that include absent genital squamous epithelium. This study investigated the expression of p63 in the human cervical transformation zone and early cervical neoplasia.

METHODS

Tissue localization of p63 was determined by immunohistochemistry in a wide range of epithelia. A correlation was also made between p63 expression and squamous basal cell (keratin 14), endocervical columnar cell (mucicarmine), and cell-cycle specific (Ki-67) markers.

RESULTS

p63 expression by immunostaining delineated basal and parabasal cells of maturing ectocervical squamous mucosa, squamous metaplasia in the cervix, and basal and subcolumnar cells of the cervical transformation zone. In atrophic epithelia immunostaining for p63 was present in all cell strata. In early cervical neoplasia, p63 expression was inversely correlated with both squamous cell maturation and nonsquamous differentiation in CIN. This biomarker also identified basal cells in a subset of preinvasive cervical neoplasms with endocervical cell differentiation that were bcl-2 and keratin 14 negative.

CONCLUSIONS

In the lower female genital tract, p63 is preferentially expressed in immature cells of squamous lineage and is not linked to cell proliferation. The broader range of p63 expression relevant to keratin 14 and bcl-2 indicates that p63 may identify additional subsets of benign and neoplastic epithelial basal cells in the cervical transformation zone and may be useful in studying cell differentiation in the early stages of neoplastic change in this region.

Identification of a basal/reserve cell immunophenotype in benign and neoplastic endometrium: a study with the p53 homologue p63

BACKGROUND

Metaplastic differentiation, including squamous, mucinous, and tubal (ciliated), is common in both benign and neoplastic endometrium, and the cell of origin for this pathway is poorly understood. In this study, expression of a marker for basal and reserve cells in cervical squamous mucosa, designated p63, was investigated in a spectrum of endometrial alterations.

METHODS

One hundred ninety different endometria from 132 patients were examined, including fetal (6), premenarchal (3), benign cyclic (29) and noncyclic (54), hyperplastic (14), and neoplastic (93) endometrial glandular epithelia. The latter included conventional endometrioid carcinomas with and without mucinous, ciliated, and squamous metaplasia, and uterine papillary serous carcinoma (UPSC).

RESULTS

p63 expression was identified in basal/subcolumnar cells in the fetal endometrium in a distribution similar to that in basal/reserve cells of the cervix. Staining was confined to individual scattered basal and suprabasal cells in cycling endometrium. In polyps and postmenopausal endometria, focal clusters of p63-positive cells were identified in inactive glands or surface epithelium. Metaplastic (squamous or mucinous) epithelia, either alone or in conjunction with hyperplasias or carcinomas, exhibited the most intense staining, primarily in basal or subcolumnar cells. In some cases, immediately adjacent nonmetaplastic columnar epithelium also stained positive. UPSCs contained only rare scattered p63-positive cells.

CONCLUSIONS

Cells with a basal or reserve cell phenotype exist in the endometrium during fetal life, are not conspicuous during the reproductive years, but may emerge during shifts in differentiation. Whether these cells signify specialized multipotential endometrial cells is not clear, but the similarity of these cells to basal/reserve cells of the cervix and their association with neoplasia merit further study.

p63 is a prostate basal cell marker and is required for prostate development

The p53 homologue p63 encodes for different isotypes able to either transactivate p53 reporter genes (TAp63) or act as p53-dominant-negatives (DeltaNp63). p63 is expressed in the basal cells of many epithelial organs and its germline inactivation in the mouse results in agenesis of organs such as skin appendages and the breast. Here, we show that prostate basal cells, but not secretory or neuroendocrine cells, express p63. In addition, prostate basal cells in culture predominantly express the DeltaNp63alpha isotype. In contrast, p63 protein is not detected in human prostate adenocarcinomas. Finally, and most importantly, p63(-/-) mice do not develop the prostate. These results indicate that p63 is required for prostate development and support the hypothesis that basal cells represent and/or include prostate stem cells. Furthermore, our results show that p63 immunohistochemistry may be a valuable tool in the differential diagnosis of benign versus malignant prostatic lesions.

P63 and P73: P53 mimics, menaces and more

Inactivation of the tumour suppressor p53 is the most common defect in cancer cells. The discovery of its two close relatives, p63 and p73, was therefore both provocative and confounding. Were these new genes tumour suppressors, p53 regulators, or evolutionary spin-offs? Both oncogenic and tumour-suppressor properties have now been attributed to the p53 homologues, perhaps reflecting the complex, often contradictory, protein products encoded by these genes. p63 and p73 are further implicated in many p53-independent pathways, including stem-cell regeneration, neurogenesis and sensory processes.

[Construction and nucleotide sequence assay of human anti-HBs variable region single-chain antibody gene]

The VH and Vk gene which were acquired using phage display technology have been combined by a linker encoding a flexible peptide (Gly4 Ser)3 to form a single-chain. Its nucleotide sequence was assayed after cloning the scFv gene into middle plasmid. The successful construction of single-chain gene lays the foundations for the subsequent expression and production of double functional antibody.

Carboxyl-terminal fragments of Alzheimer beta-amyloid precursor protein accumulate in restricted and unpredicted intracellular compartments in presenilin 1-deficient cells

Absence of functional presenilin 1 (PS1) protein leads to loss of gamma-secretase cleavage of the amyloid precursor protein (betaAPP), resulting in a dramatic reduction in amyloid beta peptide (Abeta) production and accumulation of alpha- or beta-secretase-cleaved COOH-terminal fragments of betaAPP (alpha- or beta-CTFs). The major COOH-terminal fragment (CTF) in brain was identified as betaAPP-CTF-(11-98), which is consistent with the observation that cultured neurons generate primarily Abeta-(11-40). In PS1(-/-) murine neurons and fibroblasts expressing the loss-of-function PS1(D385A) mutant, CTFs accumulated in the endoplasmic reticulum, Golgi, and lysosomes, but not late endosomes. There were some subtle differences in the subcellular distribution of CTFs in PS1(-/-) neurons as compared with PS1(D385A) mutant fibroblasts. However, there was no obvious redistribution of full-length betaAPP or of markers of other organelles in either mutant. Blockade of endoplasmic reticulum-to-Golgi trafficking indicated that in PS1(-/-) neurons (as in normal cells) trafficking of betaAPP to the Golgi compartment is necessary before alpha- and beta-secretase cleavages occur. Thus, although we cannot exclude a specific role for PS1 in trafficking of CTFs, these data argue against a major role in general protein trafficking. These results are more compatible with a role for PS1 either as the actual gamma-secretase catalytic activity or in other functions indirectly related to gamma-secretase catalysis (e.g. an activator of gamma-secretase, a substrate adaptor for gamma-secretase, or delivery of gamma-secretase to betaAPP-containing compartments).

Bifunctional adsorbents for hydrophobic displacement chromatography of proteins

The separation of pancreatic trypsinogen and alpha-chymochypsinogen A by displacement chromatography was tested on a bifunctional adsorbent containing both butyl and carboxymethyl groups. Methacrylic triblock copolymer was synthesized and used as the displacer. Compared to the displacement results on commercial Butyl-Sepharose, it was found that both the separation and recovery of trypsinogen and alpha-chymochypsinogen A were improved. Adsorption isotherms of proteins were measured on both the commercial Butyl-Sepharose and the synthesized bifunctional adsorbents. It was found that the improvement of protein separation on bifunctional adsorbents was attributed to the alteration of the adsorption of trypsinogen. Charge repulsion between trypsinogen and the negatively charged carboxymethyl groups may account for the alteration. In addition, taking advantage of the effect of charge repulsion, the column regeneration became much easier on the column packed with bifunctional adsorbents.

Stratified mucin-producing intraepithelial lesions of the cervix: adenosquamous or columnar cell neoplasia?

BACKGROUND

Squamous (CIN) and glandular (ACIS) intraepithelial lesions often coexist in the same cervical specimen. However, a less common and little studied variant consists of a stratified epithelium resembling CIN in which conspicuous mucin production is present (Stratified Mucin-producing Intraepithelial LEsions (SMILE). This report describes the phenotypic characteristics of the SMILE, its associated lesions, and its immunophenotype.

METHODS

Eighteen SMILEs were identified by the presence of conspicuous cytoplasmic clearing or vacuoles in lesions otherwise resembling CIN. The morphologic spectrum of SMILEs was detailed; including associated intraepithelial and invasive cervical neoplasms. In addition, selected cases were stained for mucicarmine, markers of squamous cell/reserve cell differentiation (keratin-14 and p63), and proliferative activity (Mib-1).

RESULTS

Stratified neoplastic epithelial cells with a high Mib-1 index and a rounded or lobular contour at the epithelialstromal interface characterized SMILEs. In contrast to CIN, in which mucin droplets are confined to surface cells, mucin was present throughout the epithelium, varying from indistinct cytoplasmic clearing to discrete vacuoles. SMILEs were distinguished from benign metaplasia by nuclear hyperchromasia and a high Mib-1 index. All but three coexisted with either a squamous (CIN) or glandular (ACIS) precursor lesion. Nine of nine coexisting invasive carcinomas contained glandular, adenosquamous differentiation, or both. SMILEs stained negative for keratin-14 and variably for p63. When present, staining with p63 was confined to basal areas of SMILEs and was absent in areas of columnar differentiation.

CONCLUSIONS

SMILEs are unusual cervical intraepithelial lesions best classified as variants of endocervical columnar cell neoplasia based on immunophenotype. The distribution and immunophenotype of SMILEs are consistent with a neoplasm arising in reserve cells in the transformation zone. The coexistence of a wide spectrum of intraepithelial and invasive cell phenotypes suggests that SMILEs are a marker for phenotypic instability, emphasizing the importance of identifying SMILEs and ensuring a complete examination of specimens containing this unusual precursor lesion.

[Studies on Legionella-contamination to the air-conditioning cooling towers in big hotels and on its seroprevalence in the related populations in Beijing]

OBJECTIVE

To understand the situation of Legionella-contamination at cooling towers of big hotel and the level of Legionella-infection among related populations in Beijing.

METHODS

Thirty-eight cooling towers of hotels were chosen for detection of Legionella. Four hundred and fourteen staff members from the hotels were selected as exposure group, with another 414 from general population as controls, for the detection of Legionella antibodies.

RESULTS

Sixteen strains of Legionella pneumophila (Lp) were isolated from 21 of the 38 cooling towers, and the predominant strain was Lp serum group 1 (50%, 8/16). The seroprevalence of Lp antibodies for the exposure group was 9.9% (41/414), comparing to 3.5% (14/414) from the control group. The difference was statistically significant (chi(2) = 14.2, P < 0.01).

CONCLUSION

Legionella was discovered in air-conditioning cooling tower of the hotels, which threatened the health to the population exposed to it.

Down-regulation of p63 is required for epidermal UV-B-induced apoptosis

In the epidermis, p53 plays an important role in UV-B protection that led us to examine the role, if any, that p63, a p53 homologue highly expressed in the basal layer of the epidermis, might play in the epidermal UV-B response. One p63 isoform, deltaNp63alpha, decreased dramatically in normal keratinocytes or newborn epidermis at both the protein and RNA levels after UV-B irradiation. In an attempt to further investigate the significance of the UV-B-induced decrease of this p63 isoform as well as further delineate the function of p63 in the epidermis, we generated transgenic mice that constitutively express deltaNp63alpha in the mouse epidermis using the loricrin promoter (ML.deltaNp63alpha). The ML.deltaNp63alpha mouse epidermis developed normally, with no overt phenotype and an unaltered proliferation rate. When challenged by UV-B exposure, the ML.deltaNp63alpha mice exhibited a 40-45% decrease in the number of apoptotic cells in the epidermis as compared with nontransgenic littermates. These results suggest that aberrant expression of deltaNp63alpha altered the UV-B-induced apoptotic pathway in the transgenic epidermis, proving that down-regulation of deltaNp63alpha in response to UV-B is important to epidermal apoptosis. The forced overexpression of deltaNp63alpha may act via a dominant negative effect on the endogenous p53 transcriptional activity required for UV-B-induced apoptosis.

An anti-apoptotic role for the p53 family member, p73, during developmental neuron death

p53 plays an essential pro-apoptotic role, a function thought to be shared with its family members p73 and p63. Here, we show that p73 is primarily present in developing neurons as a truncated isoform whose levels are dramatically decreased when sympathetic neurons apoptose after nerve growth factor (NGF) withdrawal. Increased expression of truncated p73 rescues these neurons from apoptosis induced by NGF withdrawal or p53 overexpression. In p73-/- mice, all isoforms of p73 are deleted and the apoptosis of developing sympathetic neurons is greatly enhanced. Thus, truncated p73 is an essential anti-apoptotic protein in neurons, serving to counteract the pro-apoptotic function of p53.

The interaction of lead exposure and arylsulfatase A genotype affects sulfatide catabolism in human fibroblasts

Lead exposure causes cognitive and behavioral deficits in some affected children. We propose that a contributing mechanism for the neurological damage is that lead induces critically low levels of arylsulfatase A (ASA) at sensitive stages of nervous system development. It is hypothesized that the combined effects of a single nucleotide polymorphism (SNP) in human ASA which results in reduced levels of the enzyme, and lead concentrations which decrease ASA activity culminate in cellular enzymic activity that is below a critical threshold required for the maintenance of normal nervous system function. Human fibroblasts grown in the presence of 20 microM lead acetate exhibit a more than 60% decrease of cellular ASA enzyme protein. Lead treatment of cells from individuals with the SNP(s) of pseudodeficient ASA, but not those from subjects with the normal gene, results in a significant decrease in ability of the cells to desulfate sulfatide, the substrate of ASA. The decrease in the degree of sulfatide catabolism is consistent with possible enhanced lead-induced neurobehavioral effects in individuals homozygous for the pseudodeficiency polymorphism(s) of ASA.

Adenoid basal carcinomas of the cervix: a unique morphological evolution with cell cycle correlates

Adenoid basal carcinoma (ABC) is a rare cervical carcinoma of postmenopausal women composed of small basal-type (basaloid) cells with focal endocervical ("adenoid") differentiation. ABCs are associated with high-grade squamous intraepithelial lesions (HSIL) and contain integrated human papillomavirus type 16 DNA. However, ABCs have a favorable prognosis and do not metastasize. Five (5) ABCs were analyzed histologically for a marker distinguishing basal/ squamous from columnar (adenoid) differentiation (p63) and cell cycle activity (Ki-67), and compared with 20 cervical (CC) carcinomas. In contrast to other CCs, ABCs contained 4 distinct components, including (1) a classic HSIL; (2) a limited invasive component with squamoid maturation, often with a discrete layer of peripheral basal cells; (3) outgrowth of small basal cells from either HSIL or squamoid areas; (4) focal endocervical (adenoid) differentiation. ABCs showed distinct differences in cell cycle activity relative to CCs. Ki-67 positivity was high in associated HSILs but remained high and concentrated in the suprabasal cells of the invasive squamoid component of ABC. Moreover, proliferative index was variable to sharply reduced in areas of basaloid and adenoid differentiation, in contrast to conventional CCs. ABC is a unique neoplasm, not only by its transition through multiple phenotypes during invasion, but also by a proliferative index that is high in more mature neoplastic cells during the infiltrative process and reduced with progressive basal differentiation. The precise mechanism underlying this unique process of tumor evolution is unclear. However, the postmenopausal status of these patients suggests that host factors related to aging may influence tumor evolution and morphology after HPV 16 infection.

Large degree of racemization observed in the amide bond forming reaction on silica gel

A systematic study of racemization from the coupling of DNB-L-Leu and 3-aminopropyl silica gel with several amide coupling reagents was investigated. Significant amounts of racemization were observed from all except one coupling reagent. In comparison, similar reactions completed in homogeneous solution can be accomplished with much lower racemization and in much higher yields.

Nicotine reverses GABAergic inhibition of long-term potentiation induction in the hippocampal CA1 region

Nicotine is known to enhance cognitive function but the mechanism is unknown. The present study examined the modulatory effect of nicotine on the induction of long-term potentiation (LTP), a synaptic model of learning and memory. A weak tetanic stimulation consisting of 20 pulses at 100 Hz induced stable LTP in the hippocampal CA1. The induction of LTP was completely blocked if the tetanus was delivered in the presence of muscimol (2.5 microM), a gamma-aminobutyric acid (GABA) receptor agonist. This inhibition was sensitive to, and reversed by, not only nicotinic acetylcholine receptor (nAChR) agonists (nicotine and epibatidine), but also the alpha7 nAChR-selective antagonist methyllycaconitine (MLA). Furthermore, ACh-puff activation of alpha7 nAChRs on feedforward interneurons induced inhibitory postsynaptic currents in pyramidal cells that were blocked by nicotine or MLA. In addition, nicotine reduced field monosynaptic inhibitory postsynaptic potentials in the presence of MLA. These results suggest not only two pathways of nicotine-induced disinhibition of pyramidal cells, one involving desensitization of alpha7 nAChRs and the other involving non-alpha7 nAChRs, but also two potential mechanisms underlying the modulatory effect of nicotine on LTP induction, both reducing GABAergic inhibition, thereby indirectly increasing the excitability of pyramidal cells.

Molecular characterization of pncA gene mutations in Mycobacterium tuberculosis clinical isolates from China

A sample of 35 pyrazinamide (PZA)-resistant and 30 PZA-susceptible clinical isolates recovered from Beijing and Taiyuan City, China were characterized by SSCP and sequence analysis for mutations in the pncA gene that encodes the Mycobacterium tuberculosis PZase. The purpose of this study was to understand the molecular basis and the characteristics of pncA gene mutations and its relation to PZA resistance in M. tuberculosis strains from China. Several mutations with base changes leading to amino acid substitutions were found in the PZA-resistant isolates. No mutations were seen in the 243 PZA-susceptible isolates. Among the 35 PZA-resistant isolates, 32 isolates (91.4%) had nucleotide substitutions, insertions and deletions that resulted in amino-acid substitution; or frameshifts in some strains. Other previously uncharacterized mutations were found as follows: Asn118->Thr, CG insertion at position 501; CC insertion at nucleotide position 403; a 8 base-pair deletion at start codon; Pro54->Thr; AG insertion at 368; Tyr41->His, Ser88->stop, and A insertion at nucleotide position 301. IS6110 subtyping revealed that each strain was unique; indicative of the epidemiologic independence of the isolates.