Temporal macrodynamics and microdynamics of the postoperative impedance at the tissue-electrode interface in deep brain stimulation patients.

OBJECTIVE: To study the temporal dynamics of tissue impedance after deep brain stimulation (DBS). BACKGROUND: DBS therapy commonly employs a constant voltage approach, and current delivery to the tissue is a function of electrode-tissue impedance. It is presumed that impedance fluctuates early postimplantation, with implications for variations in current delivery and therapeutic efficacy. We hypothesised that the largest variation will be recorded early after surgery, followed by stabilisation. METHODS: Review of impedance checks of implanted DBS systems at standard parameters during the first five months postimplantation. All measurement time points were binned into 1-week periods, and we used repeated measures analysis of variance with Tukey pairwise multiple comparisons correction. The analysis was repeated after normalising impedance values for each subject to that patient's baseline value. RESULTS: There was an initial (non-significant) drop in impedance at week 1, followed by significant increase at week 3 (p=0.0002). There were no further significant differences in impedance values at subsequent time points. Analysis of normalised data showed a significant difference between the initial measurement in postoperative week 1 (normalised value 1) and week 3 (normalised value 1.73, p<0.0001), with no further difference among the subsequent weekly points during the 5-month follow-up. No significant hourly variations were found at any time points. CONCLUSIONS: We found major changes in impedance within the first month postimplantation, with no further variation. This is an important confirmation in patients of this temporal dynamics of the impedance of implanted DBS hardware, with potential therapeutic implications.

Outcome of the Lima periurethral constrictor in children and adolescents: a European perspective.

PURPOSE: The Lima constrictor was described in 1996 as a less complex and less expensive alternative to the artificial urinary sphincter for use in cases of pediatric neuropathic sphincter incontinence. The device provides a fixed periurethral resistance which creates continence, yet allows urethral catheterization without the need to deflate the cuff. We report our multicenter experience, and continence, revision and erosion rates. MATERIALS AND METHODS: We performed a retrospective review of 14 consecutive patients who underwent insertion of the periurethral constrictor (Silimed, Rio de Janeiro, Brazil) between 2005 and 2011. Data are presented as medians (range). RESULTS: A total of 14 patients (13 male, 1 female) with spina bifida (10), sacral agenesis (3) and Hirschsprung disease (1) underwent insertion of the constrictor at a median age of 12 years (range 8 to 20). All patients were wet despite clean intermittent catheterization, medical therapy and/or previous surgery. Eleven patients underwent simultaneous bladder augmentation and/or Mitrofanoff formation. The constrictor was activated a median of 8 weeks (range 2 to 99) after the procedure in 11 patients whereas 3 became dry without activation. Complications occurred in 4 patients (29%), including spontaneous bladder perforation and constrictor erosion (1), tubing disconnection requiring revision (2) and wound infection (1). At a median of 23 months of followup (range 7 to 77) 13 patients were dry and 1 was damp. All patients performed urethral or Mitrofanoff clean intermittent catheterization. The continence rate with the device in situ was 92%. CONCLUSIONS: At a median followup of 23 months the Lima constrictor provided a 92% continence rate with erosion and revision rates of 7% and 14%, respectively. Interim results suggest that the constrictor provides a safe and effective surgical option, particularly in patients who are unable to void to completion.

Injury patterns of patients with upper limb and hand trauma sustained during the COVID-19 pandemic lockdown in the UK: a retrospective cohort study.

This work aimed to identify the lead causes of upper limb injury presenting to a busy hand and major trauma unit during the UK COVID-19 domestic lockdown period, in comparison to a cohort from the same period one year previously. Hand and upper limb injuries presenting to the host organization during a pre-lockdown period (23rd March 2019-11th May 2019) and the formal UK lockdown period (23rd March 2020-11th May 2020) were compared, using data collated from the host institution's hand surgery database. The UK lockdown period was associated with a 52% fall in the number of patients presenting to the service with hand and upper limb injuries (589 pre-lockdown vs. 284 during lockdown). There was a significant increase in the proportion of injuries due to machinery use during lockdown (38, 6.5% pre-lockdown vs. 33, 11.6% during lockdown, P = 0.009), other etiologies were consistent. The proportion requiring surgical management were similar (n = 272, 46.2% pre-lockdown vs. n = 138, 48.6% during lockdown, P = 0.50). The proportion requiring overnight admission fell (n = 94, 16.0% pre-lockdown vs. 29, 10.2% during lockdown, P = 0.022). COVID-19 related lockdown in the UK resulted in a reduction in the presenting numbers of hand related injuries; however almost half of these patients still required surgery. These data may be of use to other hand surgery centers for resource planning during future lockdown periods, and for injury prevention strategies in the post-COVID-19 world.

Diet as prophylaxis and treatment for venous thromboembolism?

BACKGROUND: Both prophylaxis and treatment of venous thromboembolism (VTE: deep venous thrombosis (DVT) and pulmonary emboli (PE)) with anticoagulants are associated with significant risks of major and fatal hemorrhage. Anticoagulation treatment of VTE has been the standard of care in the USA since before 1962 when the U.S. Food and Drug Administration began requiring randomized controlled clinical trials (RCTs) showing efficacy, so efficacy trials were never required for FDA approval. In clinical trials of 'high VTE risk' surgical patients before the 1980s, anticoagulant prophylaxis was clearly beneficial (fatal pulmonary emboli (FPE) without anticoagulants = 0.99%, FPE with anticoagulants = 0.31%). However, observational studies and RCTs of 'high VTE risk' surgical patients from the 1980s until 2010 show that FPE deaths without anticoagulants are about one-fourth the rate that occurs during prophylaxis with anticoagulants (FPE without anticoagulants = 0.023%, FPE while receiving anticoagulant prophylaxis = 0.10%). Additionally, an FPE rate of about 0.012% (35/28,400) in patients receiving prophylactic anticoagulants can be attributed to 'rebound hypercoagulation' in the two months after stopping anticoagulants. Alternatives to anticoagulant prophylaxis should be explored. METHODS AND FINDINGS: The literature concerning dietary influences on VTE incidence was reviewed. Hypotheses concerning the etiology of VTE were critiqued in relationship to the rationale for dietary versus anticoagulant approaches to prophylaxis and treatment.Epidemiological evidence suggests that a diet with ample fruits and vegetables and little meat may substantially reduce the risk of VTE; vegetarian, vegan, or Mediterranean diets favorably affect serum markers of hemostasis and inflammation. The valve cusp hypoxia hypothesis of DVT/VTE etiology is consistent with the development of VTE being affected directly or indirectly by diet. However, it is less consistent with the rationale of using anticoagulants as VTE prophylaxis. For both prophylaxis and treatment of VTE, we propose RCTs comparing standard anticoagulation with low VTE risk diets, and we discuss the statistical considerations for an example of such a trial. CONCLUSIONS: Because of (a) the risks of biochemical anticoagulation as anti-VTE prophylaxis or treatment, (b) the lack of placebo-controlled efficacy data supporting anticoagulant treatment of VTE, (c) dramatically reduced hospital-acquired FPE incidence in surgical patients without anticoagulant prophylaxis from 1980 - 2010 relative to the 1960s and 1970s, and (d) evidence that VTE incidence and outcomes may be influenced by diet, randomized controlled non-inferiority clinical trials are proposed to compare standard anticoagulant treatment with potentially low VTE risk diets. We call upon the U. S. National Institutes of Health and the U.K. National Institute for Health and Clinical Excellence to design and fund those trials.

The diagnostic value of abdominal ultrasound, urine cytology and prostate-specific antigen testing in the lower urinary tract symptoms clinic.

INTRODUCTION: Lower urinary tract symptoms (LUTS) affect 18-26% of men aged 40-79 years, many of whom present with a fear of having cancer. Current guidelines for the assessment of LUTS focus mainly upon benign prostatic hypertrophy. It has been our practice to perform an abdominal ultrasound scan (USS), a prostate-specific antigen (PSA) blood test and urine cytology during the assessment of males presenting with LUTS to investigate the alternative potentially life-threatening causes for LUTS. We report on the added value of these tests during the assessment of men with LUTS. RESULTS: A total of 263/3976 (6.6%) patients investigated for LUTS were found to have incidental urological malignancies, urinary tract calculi or abdominal aortic aneurysms (AAA). Abdominal USSs resulted in the incidental diagnosis of four renal carcinomas (0.1%), 45 AAAs (incidence = 1.1%) and 44 urinary tract calculi (1.1%). Urine cytology testing and bladder USSs helped diagnose 17 new bladder cancers (0.4%), five of which did not present with haematuria. Patients found to have an elevated age-specific PSA had a 23.6% chance of being diagnosed with prostate cancer (3.8%). CONCLUSION: The addition of abdominal ultrasound scanning, urine cytology and PSA testing as part of an LUTS assessment protocol can help to diagnose significant, potentially life-threatening conditions in up to 6.6% of patients. While the pick up rate of each individual condition is not higher in the LUTS patient than in the general population, the combined pick up rate may justify these additional investigations.

To what extent might deep venous thrombosis and chronic venous insufficiency share a common etiology?

According to the valve cusp hypoxia hypothesis (VCHH), deep venous thrombosis is caused by sustained non-pulsatile (streamline) venous blood flow. This leads to hypoxemia in the valve pockets; hypoxic injury to the inner (parietalis) endothelium of the cusp leaflets activates the elk-1/egr-1 pathway, leading to leukocyte and platelet swarming at the site of injury and, potentially, blood coagulation. Here, we propose an extension of the VCHH to account for chronic venous insufficiency. First, should the foregoing events not proceed to frank thrombogenesis, the valves may nevertheless be chronically injured and become incompetent. Serial incompetence in lower limb valves may then generate ''passive'' venous hypertension. Second, should ostial valve thrombosis obstruct venous return from muscles via tributaries draining into the femoral vein, as Virchow illustrated, ''active'' venous hypertension may supervene: muscle contraction would force the blood in the vessels behind the blocked ostial valves to re-route. Passive or active venous hypertension opposes return flow, leading to luminal hypoxemia and vein wall distension, which in turn may impair vasa venarum perfusion; the resulting mural endothelial hypoxia would lead to leukocyte invasion of the wall and remodelling of the media. We propose that varicose veins result if gross active hypertension stretches the valve ''rings'', rendering attached valves incompetent caudad to obstructed sites, replacing normal centripetal flow in perforating veins with centrifugal flow and over-distending those vessels. We also discuss how hypoxemia-related venous/capillary wall lesions may lead to accumulation of leukocytes, progressive blockage of capillary blood flow, lipodermosclerosis and skin ulceration.

Malignant transformation of murine fibroblasts by a human c-Ha-ras-1 oncogene does not require a functional epidermal growth factor receptor.

Although mutations in ras genes are thought to be important for the development of about 20% of human tumors, almost nothing is known about the way in which these mutations lead to cellular transformation. The known biochemical properties of the 21-kilodalton ras proteins suggest that they may behave as G proteins, regulating the proliferation of cells in response to growth factor stimulation of a receptor. Although the putative receptor(s) has not been identified, several lines of evidence, in particular the fact that rodent cell lines containing ras oncogenes produce transforming growth factor alpha, have suggested that the epidermal growth factor (EGF) receptor is involved in ras transformation. Here we show that murine fibroblasts with no EGF receptors can be transformed to a completely malignant phenotype with a mutated ras gene. It appears, therefore, that the EGF receptor is not required for ras-mediated transformation of these cells.

Myogenic expression of an injectable protease-resistant growth hormone-releasing hormone augments long-term growth in pigs.

Ectopic expression of a new serum protease-resistant porcine growth hormone-releasing hormone, directed by an injectable muscle-specific synthetic promoter plasmid vector (pSP-HV-GHRH), elicits growth in pigs. A single 10 mg intramuscular injection of pSP-HV-GHRH DNA followed by electroporation in three-week-old piglets elevated serum GHRH levels by twofold to fourfold, enhanced growth hormone secretion, and increased serum insulin-like growth factor-I by threefold to sixfold over control pigs. After 65 days the average body weight of the pigs injected with pSP-HV-GHRH was approximately 37% greater than the placebo-injected controls and resulted in a significant reduction in serum urea concentration, indicating a decrease in amino acid catabolism. Evaluation of body composition indicated a uniform increase in mass, with no organomegaly or associated pathology.

[Patio repair for urethrocutaneous fistulae : Results of a multicentre retrospective study]. / PATIO-Repair zum Harnröhrenfistelverschluss : Ergebnisse einer multizentrischen, retrospektiven Studie.

BACKGROUND: Urethrocutaneous (UC) fistulae are common complications after hypospadias surgery and they have been a serious problem for surgeons since the repair was first attempted. We present the results of our multicentre retrospective study for repairing UC fistulae using the Patio ("preserve the tract and turn it inside out") repair described by Malone. MATERIALS AND METHODS: A total of 16 boys (Eschweiler 2, Lingen 4, Reading 10) at the ages of 1-10 years were treated for UC fistulae. Instead of excising the fistula tract, it is preserved and turned inside out, this creates a flap valve inside the urethral lumen. After a circumferential incision around the skin and meticulous dissection of the fistula tract, a 2/0 nylon suture is passed down the tract and brought out through the external urinary meatus. As a result, the fistula tract is inserted into the urethral lumen. In order to keep the fistula tract inverted, it is sutured to the tip of the external urinary meatus, or fixed by an angler lead (modification from Lingen). Due to the narrow base, the excess tissue atrophies postoperatively and leads to an appealing cosmetic result. RESULTS: A total of 9 fistula repairs were performed on an outpatient basis without using a transurethral catheter; 7 boys were treated on an inpatient basis with an average length of stay in the hospital for 1-2 days with/without catheterization. During a mean follow-up of up to 4.5 years, only one fistula recurrence occurred; no other complications were observed. CONCLUSION: The Patio repair for urethrocutaneous fistula is an outpatient, simply reproducible surgical technique without the necessity of transurethral catheterization. The short-term results are impressive; long-term results of a larger patient cohort will follow.

[Urethral centralization and pseudo-glans formation after partial penectomy]. / Zentralisierung der Harnröhre und Pseudoglansbildung nach partieller Penektomie.

The management of penile cancer has altered dramatically over the last decade. Confidence to excise lesions safely with smaller margins has led to the adoption of penile-preserving techniques and in turn improved the functional and cosmetic results. Patients undergoing partial penectomy (PP) find that the urethral meatus is located in an abnormal ventral position. In addition, there is a high risk of meatal stenosis. We describe our novel technique that allows the urethral meatus to be centralised after PP and creation of a pseudo-glans and wide meatus and therefore maintain the cosmetic appearance of the penis after split thickness skin grafting. The UCAPP technique allows the restoration of the normal meatal location and creation of a pseudo-glans in case of partial penectomy and therefore can improve the overall cosmetic appearance and reduce the psychological morbidity.

The aetiology of deep venous thrombosis.

Most ideas about the pathogenesis of deep venous thrombosis (DVT) are dominated by a 'consensus model' first articulated around 1962. This model invokes 'Virchow's triad' and attributes thrombogenesis in veins to some combination of 'hypercoagulability', 'stasis' and 'intimal injury'. This arose as a by-product of studies on the mechanisms of haemostasis and bleeding diatheses that were at best only indirectly relevant to thrombosis, and there are reasons for doubting the causal significance of 'hypercoagulability' and 'stasis' in the aetiology of DVT. Proponents of the consensus model make little reference to a substantial literature, mostly historical, that: (a) emphasizes the significance of the venous valve pockets (VVP) and blood rheology in DVT pathogenesis; and (b) describes morphological features specific to venous thrombi that a valid aetiological model must explain. This literature provides the basis for an alternative hypothesis of DVT aetiology, published some 30 years ago, which has been experimentally corroborated and is compatible with recent cell and molecular biological studies of the venous endothelium. We review this alternative hypothesis, considering its potential value for future research on DVT and embolism, and its significance for clinical practice.

Tumor destruction and kinetics of tumor cell death in two experimental mouse tumors following photodynamic therapy.

The effect of photodynamic therapy (PDT) on tumor growth as well as on tumor cell survival in vitro and in vivo was studied in the EMT-6 and RIF experimental mouse tumor systems. In vitro, RIF cells were more sensitive towards PDT than were EMT-6 cells when incubated with porphyrin (25 micrograms/ml, dihematoporphyrin ether) and subsequently given graded doses of light. In vivo, both tumor types responded to PDT (EMT-6, dihematoporphyrin ether, 7.5 mg/kg; RIF, dihematoporphyrin ether, 10 mg/kg; both followed 24 hr later by 135 J of light at 630 nm/sq cm) with severe vascular disruption and subsequent disappearance of tumor bulk. However, whereas the cure rate for EMT-6 tumors was 90%, it was 0% for RIF tumors. Raising the light dose to 200 J/sq cm resulted in 100% cures for EMT-6 tumors accompanied by damage to the surrounding tissues and 13% cures for RIF tumors. Tumor cell clonogenicity following PDT in vivo was assessed using the in vitro colony formation assay. In both tumors, it was found to be nearly unaffected by PDT if the tumor tissue was excised and explanted immediately following completion of treatment. This indicates that the effect of PDT on tumor cells directly was not sufficient to decrease tumor clonogenicity even at doses which led to total macroscopic tumor destruction. Where the tumors remained in situ following PDT and explantation was delayed for varying lengths of time (1 to 24 hr), tumor cell death occurred rapidly and progressively, indicating that tumor cell damage was expressed only if the cells remained exposed to the in situ environment after treatment. The kinetics and extent of tumor cell death were very similar for both tumor types despite their difference in cure rates. The reduction in tumor clonogenicity at 4 hr post-PDT closely matched that of tumor deprived of oxygen for the same period of time, implying that one of the major factors contributing to tumor destruction may be damage of the tumor circulation and the consequences of treatment-induced changes in tumor physiology.

Deep venous thrombosis: The valve cusp hypoxia thesis and its incompatibility with modern orthodoxy.

The valve cusp hypoxia thesis (VCHT) of the aetiology of deep venous thrombosis (DVT) was adumbrated in this journal in 1977 and fully articulated in 2008, the original hypothesis having been strongly corroborated by experiments published in 1981 and 1984. It presents a unitary account of the pathogenesis of venous thrombosis and embolism that is rooted in the pathophysiological tradition of Hunter, Virchow, Lister, Welch and Aschoff, a tradition traceable back to Harvey. In this paper we summarise the thesis in its mature form, consider its compatibility with recent advances in the DVT field, and ask why it has not yet been assimilated into the mainstream literature, which during the past half century has been dominated by a haematology-orientated 'consensus model'. We identify and discuss seven ways in which the VCHT is incompatible with these mainstream beliefs about the aetiology of venous thrombosis, drawing attention to: (1) the spurious nature of 'Virchow's triad'; (2) the crucial differences between 'venous thrombus' and 'clot'; the facts that (3) venous thrombi form in the valve pockets (VVPs), (4) DVT is not a primarily haematological condition, (5) the so-called 'thrombophilias' are not thrombogenic per se; (6) the conflict between the single unitary aetiology of DVT and the tacit assumption that the condition is 'multicausal'; (7) the inability of anticoagulants to prevent the initiation of venous thrombogenesis, though they do prevent the growth of thrombi to clinically significant size. In discussing point (7), we show that the VCHT indicates new approaches to mechanical prophylaxis against DVT. These approaches are then formulated as experimentally testable hypotheses, and we suggest methods for testing them preclinically using animal trials.

Testicular atrophy following paediatric primary orchidopexy: A prospective study.

BACKGROUND: With the Nordic consensus statement advocating orchidopexy at an earlier age, the present study sought to investigate the outcomes of primary paediatric orchidopexy at a tertiary UK centre. OBJECTIVE: To prospectively assess testicular atrophy following primary orchidopexy for undescended testes in a paediatric population. Secondary outcomes were complication rates and whether outcomes were dependent on grade of operating surgeon. STUDY DESIGN: Prospective data regarding age at operation, classification of the undescended testis, length of follow-up, and subjective comparison of intraoperative and postoperative testicular volumes compared with the contralateral testis were collected. Testicular atrophy was defined as >50% loss of testicular volume or a postoperative testicular volume <25% of the volume of the contralateral testis. Patients were excluded for incomplete data and follow-up <6 months. RESULTS: Data for 234 patients were analysed. Testicular atrophy occurred in 2.6% of cases. There was no reported testicular re-ascent. All secondary acquired cases underwent a previous ipsilateral hernia repair. There was no significant difference in outcomes comparing the grade of surgeon (consultant n = 8, trainee/staff-grade surgeon n = 7-8). There was a trend towards postoperative catch-up growth in approximately one fifth of cases. DISCUSSION: Previous studies have reported a testicular atrophy rate of 5%. The present study reported a similar rate of 2.6%. In agreement with a previous publication, it was also found that testicular atrophy was not dependent on the grade of operating surgeon. The mechanism for testicular catch-up growth is not well understood. Animal studies have supported the hypothesis that increased temperature has a detrimental effect on testicular volume. However, follow-up in the present cohort was short (median 6.9 months), making interpretation of this finding difficult. It is acknowledged that clinical palpation alone to determine testicular volume potentially introduces intra-observer and inter-observer error. However, prospective studies using ultrasound to determine testicular volumes following orchidopexy have reported catch-up growth. CONCLUSION: This study represented one of the larger collections of prospective assessments of outcomes following primary orchidopexy. It was acknowledged that subjectively assessing testicular volume is not ideal; however, the data correlated with similar studies.

Peptides related to thyrotrophin-releasing hormone (TRH) in human prostate and semen.

The TRH-related peptide, pGlu-Glu-ProNH2, which was first identified in rabbit prostate has recently been named fertilization-promoting peptide (FPP) because of its ability to enhance the in vitro fertilizing potential of mouse epididymal spermatozoa. This study set out to examine the nature of the TRH-related peptides in human prostate and semen but, first, the optimal conditions for collection of semen samples were investigated. FPP was degraded slowly (t1/2 = 163 min, S.E. +/- 51.3, n = 6) in seminal plasma which has allowed us to measure accurately the concentrations of FPP, after extraction of the peptide in acidified acetone precisely 5 min after ejaculation. In this way, high levels of FPP (mean: 49.5 nmol/l) were detected in normal human semen, from young men, although other TRH-related peptides did not appear to be present. We have also examined the TRH-related peptides present in prostate samples from clinical patients both with and without evidence of benign prostatic hyperplasia (BPH), by ion-exchange chromatography followed by radioimmunoassay. Substantial concentrations of FPP were observed in normal (4.10 pmol/g tissue, S.E. +/- 1.46) and BPH prostate (6.27 pmol/g tissue, S.E. +/- 1.65). In addition, a second, neutral TRH-immunoreactive peptide was always detected in BPH tissue (7.40 pmol/g tissue, S.E. +/- 1.98) with only low levels generally present in normal prostate. The possibility that the presence of high levels of the neutral peptide in prostate may be used as an indicator of the onset of BPH deserves further scrutiny.

Use of intravenous amiodarone for emergency treatment of life-threatening ventricular arrhythmias.

Efficacy, side effects and predictors of response for intravenous amiodarone were evaluated in 46 patients with recurrent drug-refractory sustained ventricular tachycardia or ventricular fibrillation, or both, who were treated with intravenous amiodarone. Of the 46 patients, 27 (58.5%) responded early to intravenous amiodarone and 6 (13%) showed a late response to amiodarone. The majority of patients who responded to intravenous amiodarone did so within the first 2 h of therapy, and all responded within 84 h. Patients with an ejection fraction greater than 25% were more likely to respond (p less than 0.05). Major side effects occurred in 13% of patients. The cumulative 2 year mortality rate due to arrhythmia recurrence or sudden death for responders discharged from the hospital was 23% and the cumulative overall 2 year mortality rate was 46%. In conclusion, intravenous amiodarone is rapidly effective in the majority of patients with recurrent ventricular tachycardia or ventricular fibrillation refractory to other drugs. The poor long-term outcome of patients who require this therapy, respond to it and are discharged on long-term oral amiodarone therapy warrants consideration of other long-term treatment of these patients. Use of intravenous amiodarone is an important new modality in the treatment of drug-refractory malignant ventricular arrhythmias.

Long-term results of amiodarone therapy in patients with recurrent sustained ventricular tachycardia or ventricular fibrillation.

Four hundred sixty-two patients, all with either documented spontaneous sustained ventricular tachycardia or cardiac arrest unresponsive to other antiarrhythmic drugs (2.6/patient), were treated with amiodarone. Thirty-five patients (7.6%) failed to respond or died during the initial oral or intravenous loading phase. The remaining 427 patients were discharged on treatment with oral amiodarone and followed up for up to 98 months. Recurrence of ventricular tachycardia or sudden cardiac death at 1, 3 and 5 years by life-table analysis was 19%, 33% and 43%, respectively, for patients discharged on amiodarone therapy. The sudden cardiac death rate was 9%, 15% and 21%, respectively, at 1, 3 and 5 years. Side effects were reported by 45% of patients after 1 year, by 61% after 2 years and by 86% after 5 years. Amiodarone was discontinued because of side effects in 14%, 26% and 37% of patients after 1, 3 and 5 years, respectively. Incidence rates of recurrence of arrhythmia, sudden cardiac death and side effects were highest in the early months and then decreased. By multivariate analysis, advanced age, low ejection fraction and a history of cardiac arrest were independent risk factors for sudden cardiac death during amiodarone therapy.

High-efficiency growth hormone-releasing hormone plasmid vector administration into skeletal muscle mediated by electroporation in pigs.

We report here a very efficient method for the in vivo transfer of therapeutic plasmid DNA into porcine muscle fibers by using electric pulses of low field intensity. We evaluated delivery of 0.1-3 mg of plasmid vectors that encode reporter secreted-embryonic alkaline phosphatase (SEAP) or therapeutic growth hormone releasing hormone (GHRH). Reporter gene studies showed that internal needle electrodes give a 25-fold increase in expression levels compared with caliper electrodes in skeletal muscle in swine. Dose and time courses were performed. Pigs injected with 0.1 mg plasmid had significantly greater weight gain than controls over 53 days (22.4 +/- 0.8 kg vs. 19.7 +/- 0.03 kg, respectively; P<0.01). The group treated with GHRH-expressing plasmid at 14 days of age demonstrated greater weight gain than controls at every time point (25.8 +/- 1.5 kg vs. 19.7 +/- 0.03 kg; P<0.01). Body composition studies by dual X-ray absorbitometry showed a 22% decrease in fat deposition (P<0.05) and a 10% increase in bone mineral density (P<0.004). Our studies demonstrate that by optimizing the electroporation method, favorable physiological changes, such as enhanced weight gain and improved body composition, can be obtained at extremely low plasmid doses in a large mammal.

Enhanced animal growth via ligand-regulated GHRH myogenic-injectable vectors.

Regulated animal growth occurred following a single electroporated injection of a mixture of two plasmids (10 microg of DNA), one expressing the GeneSwitch regulator protein, the other an inducible growth hormone releasing hormone (GHRH) gene, into the tibialis anterior muscles of adult SCID mice. Administration of the ligand mifepristone (MFP) up-regulated GHRH expression, as shown by elevations of IGF-I levels, and when MFP dosing was withdrawn, IGF-I returned to baseline levels. Five cycles of IGF-I induction were observed during a five-month period. Chronic MFP dosing for 25 days increased lean body mass, weight gain, and bone mineral density significantly compared with non-MFP treated controls. In summary, long-term drug-regulated GHRH expression was achieved following plasmid-based gene therapy, and chronic induction of GHRH expression in adult animals led to improvements in weight gain and body composition.