Neurophysiological basis of sympathetic nerve-preserving surgery for lower rectal cancer--a canine model

BACKGROUND/AIMS

The relative contribution and interrelated compensation of sympathetic signals among sympathetic components in pelvic plexus remain undefined. This study was designed to investigate the genitourinary function in response to autonomic nerve preservation and severance using a canine model.

METHODOLOGY

Eighteen mongrel dogs were randomly divided into 3 groups which received severance of the hypogastric nerves on either the right side, left side, or on both sides. The hypogastric nerves and sacral sympathetic trunks were electrically stimulated and the contraction pressure of the internal urethral orifice was measured immediately, at 1- and 3-month intervals. The ejaculation function and the length of time required to reach sexual orgasm were evaluated by manual penis-stimulation.

RESULTS

The difference between the left and right sides of the normal hypogastric nerve in contribution to sympathetic signals was insignificant. Compared with the hypogastric nerve, the bilateral sacral sympathetic trunks were functionally trivial in controlling the closure of the internal urethral orifice. The preserved side of the hypogastric nerve compensated for the loss of sympathetic signals of the severed side within 1 month and, thereafter, remained stationary. In contrast, the functional compensation of bilateral sacral sympathetic trunks for the severed bilateral hypogastric nerves was insignificant. When the hypogastric nerve was preserved in one or both sides, all dogs maintained normal antegrade ejaculation. If bilateral hypogastric nerves were severed, 50.0% (3/6) of the dogs lost both emission and ejaculation function; 33.3% (2/6) presented with retrograde ejaculation; and, 16.7% (1/6) presented with combined retrograde ejaculation and reduced antegrade ejaculation. The time required to reach sexual orgasm was not affected by the severance of the hypogastric nerve.

CONCLUSIONS

The normal genitourinary function could be maintained only when at least one side of the hypogastric nerve was preserved.

Electrophysiological mechanisms for the antiarrhythmic activities of naloxone on cardiac tissues

It has been reported that naloxone, an opioid antagonist, has antiarrhythmic activity in vivo. In Langendorff perfused rat hearts, we found that ischemia-reperfusion-induced ventricular tachyarrhythmia reverted to normal sinus rhythm after the treatment with naloxone (3 approximately 10 microM). The method of voltage and current clamp were used to study the underlying mechanism of its antiarrhythmic activity on isolated cardiac myocytes. In isolated rat ventricular and in guinea-pig and human atrial myocytes, naloxone prolonged the action potential duration reversibly. In rat ventricular myocytes, naloxone (1 approximately 30 microM) inhibited sodium current (I(Na)), transient outward potassium current (I(to)), and calcium current (I(Ca)). On the contrary, the addition of naloxone significantly increased inward rectifier potassium current (I(K1)). For the effect on I(Na), naloxone did not shift the inactivation curve of I(Na) but retarded the I(Na) recovery rate from inactivation state. Naloxone suppressed I(to) with a significant left-shift of the inactivation curve, however, the time course of I(to) recovery from inactivation was not affected. In guinea pig atrial myocytes, naloxone (10 microM) decreased the delayed rectifier K+ current (IK). These results show that naloxone exert various extent of inhibition on I(Na), I(to), IK and I(Ca). The prolongation of cardiac action potential is related to the inhibition of I(to) and IK. The antiarrhythmic activity of naloxone is more closely related to the inhibition of Na+ and K+ currents rather than the blockade of myocardial opioid receptors.

Adrenal hemangioma: two cases report

Adrenal hemangiomas are rare, nonfunctioning benign tumors. They are well circumscribed and comprise of closely adjacent vascular channels of varying sizes that are lined with a single layer of endothelium. When they occur, they are frequently located in the skin and liver. There are no characteristic symptoms of adrenal hemangioma unless the tumor reaches a size large enough to exert pressure. To our knowledge, there have been 14 clinical cases of adrenal hemangiomas reported, all with similar pathologic features. We present 2 additional cases, which were identified incidentally after non-urologic complaints (epigastric fullness and low back pain in patient 1 and patient 2, respectively). In these 2 patients, the tumors were surgically removed and diagnosed postoperatively as adrenal hemangiomas. Preoperative radiologic findings on plain film and abdominal computerized tomography showed the characteristic round calcifications with translucent centers, typical of phleboliths, to be pathognomonic of adrenal gland hemangiomas. Unfortunately, this characteristic feature of adrenal hemangioma existed in only one case report. In conclusion, the preoperative diagnosis of adrenal hemangioma is difficult but should be kept in mind as being part of the differential diagnosis of adrenal tumors.

Adrenal extramedullary hematopoietic tumor in a patient with beta-thalassemia

We report a case of adrenal extramedullary hematopoiesis in a 27-year-old woman with beta-thalassemia. She underwent cholecystectomy for gallstones and splenectomy for splenomegaly at the age of 20 years. In January 1996, she was admitted to our hospital because of a palpable nontender mass in the right subcostal area. Ultrasound, computed tomography, and magnetic resonance imaging disclosed a right suprarenal mass 7.5 x 5.8 cm in size. Surgical exploration and biopsy confirmed the diagnosis of extramedullary hematopoietic (EMH) tumor. The tumor was left in situ. Subsequent follow-up showed no increase in the size of the tumor and no progression of anemia. The patient remained asymptomatic, and no additional EMH tumor developed. Surgery or radiotherapy should be performed only when EMH tumors cause symptoms, such as during spinal cord compression. Adrenal EMH tumors should be considered in thalassemia patients with an adrenal mass, to avoid unnecessary surgical procedures.

Phase I clinical and pharmacological studies of benzylacyclouridine, a uridine phosphorylase inhibitor

Benzylacyclouridine (BAU, IND 039655) is a potent and specific inhibitor of uridine phosphorylase (UrdPase; EC 2.4.2.3). This enzyme plays a major role in regulating uridine homeostasis and also catalyzes the conversion of fluoropyrimidine nucleosides to their respective bases. Inhibition of UrdPase enzyme activity 18-24 h after 5-fluorouracil (5-FU) administration increased plasma levels of uridine and enhanced the therapeutic index of 5-FU by rescuing normal tissues. Moreover, in vitro preclinical studies have also shown that inhibiting UrdPase enzyme activity by BAU prior to administration of 5-FU increased cytotoxicity in a number of human cancer cell lines. A series of preclinical studies was performed in dogs and pigs to evaluate the pharmacological and pharmacodynamic properties of BAU. These data showed a sustained elevation in plasma uridine concentration in both animal models. The rapid degradation of a tracer dose of uridine into uracil was virtually arrested by BAU administered both p.o. or i.v. The t1/2 of BAU was 1.8-3.6 h in dogs, with bioavailability levels of 85% (30 mg/kg) and 42.5% (120 mg/kg). In pigs, the half-life varied from 1.6 to 2.3 h, with a bioavailability of 40% at 120 mg/kg. The drug was distributed into most tissues with a tissue: plasma ratio of approximately 0.7. On the basis of these preclinical studies, we performed a Phase I clinical trial of BAU in patients with advanced cancer. Patients received 200, 400, 800, and 1600 mg/m2 BAU as a single oral dose. Toxicities included grade 2 anemia, grade 1 fever, grade 1 fatigue, grade 1 constipation, and grade 1 elevation in alkaline phosphatase; none of these toxicities were observed to be dose dependent. The maximum tolerated dose and dose-limiting toxicity were not reached at the doses given. BAU plasma concentrations and area under the curve correlated linearly with the oral dose level. The pharmacokinetics of BAU were consistent with a first-order clearance, with average peak concentrations ranging from 19 microM (200 mg/m2) to 99 microM (1600 mg/m2) and tbeta1/2 ranging from 3.0 to 3.9 h at the four dose levels. Compared with baseline plasma uridine, treatment of patients with 200, 400, 800, and 1600 mg/m2 BAU increased peak uridine concentrations by 120, 150, 250, and 175%, respectively. On the basis of this clinical study, the suggested Phase II starting dose of BAU in combination with 5-FU is 800 mg/m2. Studies combining BAU with 5-FU and incorporating appropriate molecular and biochemical end points to assess the effects of this drug combination on tumor and/or surrogate tumor tissue are under way.

The impact of a clinical pathway for transurethral resection of the prostate on costs and clinical outcomes

The purpose of this study was to evaluate the effects of implementing a clinical pathway for transurethral resection of the prostate on hospital costs and procedures, outcomes, and complications. Consecutive patients who underwent transurethral resection of the prostate for benign prostate hyperplasia in our hospital before (February-August 1996) and after (October 1996-March 1997) implementation of the clinical pathway were included. Statistical analyses included Student's t-test to test the impact of the clinical pathway on resource consumption and medical care processes, and multiple linear regression to control for patient characteristics such as age, severity of disease, and comorbidity. The major findings of this study were that implementation of the clinical pathway 1) decreased resource consumption and controlled medical care expenditure; 2) influenced physicians' patterns of practice and decreased the number of procedures performed; and 3) did not affect clinical outcomes or complication rates. In conclusion, our results support the hypothesis that the clinical pathway is an effective medical management tool to contain costs, which does not adversely affect quality of care. We suggest health policy makers promote clinical pathways in more hospitals to encourage appropriate resource consumption.

Extracorporeal membrane oxygenation support for single lung transplantation in a patient with primary pulmonary hypertension

Left single lung transplantation was performed under perioperative extracorporeal membrane oxygenation (ECMO) support for a patient of primary pulmonary hypertension. Continuous ECMO in this patient for one day after the transplantation decreased the pulmonary blood flow and probably served to minimize the potential complication of reperfusion edema of the graft. During this period, the ECMO was gradually weaned so that the grafted lung could adapt itself to the gradually increased blood flow through it. The patient was extubated without difficulty 2 days alter the removal of ECMO and made a smooth recovery.

Congenital renal arteriovenous malformations: two cases report

Congenital arteriovenous malformation (AVM) of the kidney is a rare condition. Rupture of an AVM in the kidney may cause hematuria, flank pain, and urinary retention due to clots. We report 2 cases of congenital renal AVM. Both were treated with transcatheter renal arterial embolization. The signs and symptoms disappeared after embolization. On follow-up, renal function testing with a DMSA scan revealed only focal loss of renal cortical function. The clinical courses of 2 cases are reported and the literature is reviewed.

Benzylacyclouridine enhances 5-fluorouracil cytotoxicity against human prostate cancer cell lines

At a nontoxic growth inhibitory concentration benzyloxyacyclouridine (BAU), a potent and specific inhibitor of uridine phosphorylase (UrdPase), enhanced 5-fluorouracil (5-FU) cytotoxic activity against human prostate cancer PC-3 and DU-145 cell lines. The BAU/5-FU combination exhibited greater antitumor activity in vivo using PC-3 human xenografts compared to 5-FU alone, with no associated increase in animal host toxicity. The mechanism(s) responsible for the enhanced in vitro and in vivo activity of this combination may involve enhanced formation of the 5-FU nucleotide metabolites FdUMP, FdUTP, and FUTP resulting in enhanced inhibition of thymidylate synthase (TS) and increased incorporation of fluoropyrimidine metabolites into tumoral RNA and DNA.

Postpartum myocardial infarction rescued with an intraaortic balloon pump and extracorporeal membrane oxygenator

A 37-year-old woman had postpartum myocardial infarction complicated with cardiogenic shock. The infarction was attributed to diffuse coronary artery spasm caused by methylergonovine, which had been used to treat the postpartum haemorrhage due to placenta increta. The haemodynamics could not be maintained with catecholamine infusion and intraaortic balloon counterpulsation. At last, an extracorporeal membrane oxygenator was used to save her life, and the patient was successfully weaned from the machine 100 h later; she made an uneventful recovery thereafter.

Cytotoxicity and mitogenicity of adenosine triphosphate in the cochlea

Evidence is accumulating to indicate that extracellular adenosine 5'-triphosphate (ATP) may function as a neurotransmitter, neuromodulator, cytotoxin and mitogen. Many of the cells in the cochlea have ATP receptors, however, their function is unknown. The purpose of the present study was to test whether ATP may act as a cytotoxin in the cochlea. ATP was applied to acutely isolated outer hair cells (OHCs) and their shape changes monitored. In addition, ATP was applied into the cochlea by perfusion of the perilymph compartment for 2 h and the animals allowed to survive 3-4 weeks post drug application. At this time, sound-evoked cochlear potentials and distortion product otoacoustic emissions (DPOAEs) were monitored and the cochleas evaluated histologically. Results indicate that when applied to isolated OHCs, ATP (3-30 mM) induced a bleb formation in the infracuticular region of the cell that burst within a few minutes. Short OHCs were more sensitive to this effect of ATP than long OHCs. 3-4 weeks after the perilymph perfusion of ATP (60 mM; 2 h) cochlear potentials and DPOAEs were abolished, and histologically, cells in the organ of Corti and the stria vascularis were found to have been destroyed. In addition, there was loss of spiral ganglion cells and proliferating connective tissue filled varying proportions of the scala tympani and vestibuli. Application of sodium gluconate, a control, at the same concentrations had no effect either on the isolated OHCs or when applied in vivo. Results suggest that extracellular ATP or a metabolic product may act as a cytotoxin to some epithelial and neural elements in the cochlea and possibly as a mitogen to mesenchymal cells or fibrocytes.

Effects of 8-oxoberberine on sodium current in rat ventricular and human atrial myocytes

8-Oxoberberine (JKL1073A), a derivative of berberine, has been reported to exert positive inotropic action and antiarrhythmic activity, much like a class III antiarrhythmic agent. In addition to prolongation of cardiac action potential duration, JKL1073A also decreases the maximal rate of action potential upstroke. To characterize the mode of inhibition of action potential upstroke, the effects of JKL1073A on the sodium inward current (INa) of rat and human cardiac myocytes were examined by voltage clamp in a whole cell configuration. In rat ventricular myocytes, JKL1073A and quinidine inhibited INa with an average 50% inhibitory concentration (IC50) of 3.3 +/- 0.2 microM (n = 9) and 2.1 +/- 0.1 microM (n = 6), respectively. Voltage-dependent steady state inactivation curves of INa were shifted slightly by 10 microM JKL1073A but more significantly by 3 microM quinidine to negative potential. Though steady state inactivation of INa was not significantly changed by 3 microM JKL1073A, the time constant of INa recovery from inactivation state was partially prolonged from 51.7 +/- 18.5 ms to 74.1 +/- 23.8 ms. Quinidine (3 microM) prolonged the time course of INa recovery from inactivation with an associated increase of slow recovery component. Inhibition of INa by JKL1073A and quinidine was increased when cells were stimulated at higher frequency. The maximal INa obtained in cells held at -140 mV was significantly decreased by 10 microM quinidine to 45.3 +/- 2.5% of control but only partially suppressed by 10 microM JKL1073A to 85.9 +/- 8.6% of control. In human atrial myocytes, JKL1073A and quinidine suppressed INa with an average IC50 of 2.4 +/- 0.6 microM and 1.4 +/- 0.3 microM, respectively. Both JKL1073A and quinidine increased the time constant of INa recovery from inactivation. In conclusion, JKL1073A at concentrations of 3 microM and 10 microM may inhibit INa mainly by binding to open and inactivated channels. Quinidine 3 microM may inhibit INa by binding to resting, open and inactivated channels. Inhibition of INa by JKL1073A may explain the inhibition of the action potential upstroke and contribute partially to its antiarrhythmic activity.

Application of cryoablation in the management of prostate cancer

BACKGROUND

Radical prostatectomy is the most common and effective therapy for localized prostate cancer. But in addition to its surgical complications, even highly selected series carry a positive margin rate of 35 to 50%. Radiotherapy is another alternative for prostate cancer, but following radiotherapy there have been high positive biopsies reported. Cryosurgery, defined as in situ freezing and hence, devitalization of neoplastic tissues, has currently raised the interest of urologists in the management of localized prostate cancer or failed radiotherapy.

MATERIAL

Five patients underwent transperineal cryosurgery of prostate in Chang Gung Memorial Hospital. Among them, three cases were stage D, one stage B and another failed radiotherapy of stage C prostate cancer. All patients received hormone therapy too.

RESULTS

PSA declined in 3 patients and biopsies showed intraductal neoplasia. All 5 patients suffered from urine incontinence and one persisted. No mortality has been reported.

CONCLUSION

Cryoablation of the prostate is an alternative for treatment of prostate cancer.

Effects of dobutamine on aortic valve indexes in asymptomatic patients with bileaflet mechanical prostheses in the aortic valve position

We investigated the effects of alternating transvalvular flow rate on Doppler-derived aortic valve resistance and valve area in asymptomatic patients with mechanical aortic valve replacement under dobutamine infusion. The Gorlin-derived aortic valve area and continuity equation-derived aortic valve area seem to be less flow dependent; valve resistance tends to be flow dependent.

Turning points of recovery from cardiac surgery during the intensive care unit transition

OBJECTIVE

To explore the turning points of recovery from cardiac surgery of patients during the intensive care unit recovery transition.

DESIGN

A descriptive qualitative design.

SETTING

Three hospitals in northern Taiwan, Republic of China.

PATIENTS

A convenience sample consisting of 30 adult patients (15 men and 15 women) who had undergone cardiac surgery. Age range was 20 to 67 years (mean, 46.6 years).

OUTCOME MEASURES

The component, context, type, and positive or negative impact of turning points on patients' health.

INTERVENTION

Data were collected through semistructured interviews and then analyzed by using qualitative content analysis.

RESULTS

Turning points, which included events, nursing actions, and time, were examined in terms of the preceding conditions and the positive or negative health outcomes. Participants in this study fell into four main groups with regard to turning point experiences during the intensive care unit transition: those having experiences of turning points with both positive and negative outcomes (57%); those having experiences of turning points with a positive outcome only (33%); those having no experience of a turning point with either a positive or negative outcome (7%); and those having experiences of turning points with a negative outcome only (3%). Four classes of turning point experiences identified from the data encompassed "precedingness," inclusiveness, comparativeness, and multiplicity.

CONCLUSIONS

We delineated the components, context, types, and positive or negative impact of turning points on patients' health after cardiac surgery during the intensive care unit transition. We also drew information on the nature, definition, and conceptual frameworks from data analysis to describe this phenomenon.

Extracorporeal membrane oxygenation in the perioperative period of heart transplantation

Mechanical circulatory support is occasionally needed in the perioperative period of heart transplantation. Between February and May 1995, three recipients of cardiac transplant at the National Taiwan University Hospital required the use of extracorporeal membrane oxygenation (ECMO) for temporary mechanical circulatory support in the perioperative period of heart transplantation. All three patients received ECMO through the percutaneous femoral veno-arterial route. The ECMO device has a heparin-bound Carmeda Bioactive surface and centrifugal pump. Patient 1 needed ECMO for treatment of a postoperative pulmonary hypertensive crisis. Patient 2 needed ECMO for early cardiac allograft failure, possibly due to ischemia. Patient 3 needed ECMO as a bridge to his first heart transplant after acute myocardial infarction complicated with cardiogenic shock, and again as a bridge to retransplantation because of acute failure of the first cardiac transplant and finally for a temporary circulatory support during rescue treatment for acute vascular rejection of the second cardiac transplant. All three patients were successfully treated with ECMO without major complications. In conclusion, ECMO provides excellent mechanical circulatory support for some situations in the perioperative period of heart transplantation.

Emergency use of extracorporeal membrane oxygenation in a patient with post-cardiotomy myocardial stunning

Myocardial stunning refers to reversible postischemic myocardial dysfunction persisting after reperfusion. We report a patient who presented with biventricular failure, but exhibited neither definite electrocardiographic change nor elevation of serum cardiac enzyme levels in the post-cardiotomy period. The presentation was indicative of myocardial stunning. The patient's hemodynamics could not be maintained even with infusion of high doses of catecholamines. Extracorporeal membrane oxygenation successfully restored myocardial function. In conclusion, when the hemodynamic status of a patient with myocardial stunning cannot be maintained with inotropic agents, extracorporeal membrane oxygenation should be considered.

Extracorporeal membrane oxygenation support for postcardiotomy cardiogenic shock

Extracorporeal membrane oxygenation (ECMO) has had promising results in life-threatening respiratory failure and postcardiotomy cardiogenic failure. From October 1994 to October 1995, 18 patients received 19 ECMOs at National Taiwan University Hospital for severe cardiogenic shock after cardiac surgery. They included patients receiving cardiac massage or repeated bolus injections of norepinephrine to maintain blood pressure (n = 10), patients who could not be weaned off cardiopulmonary bypass after several attempts despite intraaortic balloon pumping and maximal doses of catecholamine (n = 7), and patients with progressive intractable cardiogenic shock after cardiac surgery. Venoarterial ECMO was set up via femoral artery (17 or 19 Fr cannula) and vein (19 or 21 Fr) in all patients except 2 infants. No left heart drainage was performed in any of the patients. The heparin-coated circuit (with Carmeda Bio-active Surface) was used in the last 13 patients to reduce bleeding. Ten (52.6%) of the 19 cases could be smoothly weaned off ECMO, and 6 (33.3%) of the 18 patients were discharged from the hospital in good condition. Four (80%) of the 5 patients after valvular surgery and all 3 heart transplant patients could be weaned off ECMO successfully with the survival rate being 60% and 67%, respectively. Complications included leg ischemia (n = 3), bleeding (n = 4), renal failure (n = 3), and tube rupture (n = 1). The inability to wean off ECMO was caused by multiple organ failure (n = 5), sepsis (n = 2), tube rupture (n = 1), and dysfunction of the ECMO system (n = 1). The major cause of multiple organ failure was hesitation to set up ECMO. Our preliminary results confirmed the effect of ECMO in postoperative cardiogenic shock.