Anomalous relative intensity noise transfer in ultralong random fiber lasers

We present, for the first time, an experimental demonstration of RIN noise transfer dampening at low frequencies in random distributed feedback ultralong Raman fibre lasers based on conventional telecommunication fibres. Furthermore, we present a thorough theoretical description of the phenomenon and demonstrate how our model can be used to predict the observed behaviour, identifying the general requirements for system improvement through RIN transfer reduction.

All-optical sampling and magnification based on XPM-induced focusing

We theoretically and experimentally investigate the design of an all-optical magnification and sampling function free from any active gain medium or additional amplified spontaneous noise emission. The proposed technique is based on the co-propagation of an arbitrary shaped signal together with an orthogonally polarized intense fast sinusoidal beating within a normally dispersive optical fiber. This process allows us to experimentally demonstrate a 40-GHz sampling operation as well as an 8-dB magnification of an arbitrary shaped nanosecond signal around 1550 nm in a 5-km long optical fiber. The experimental observations are in good agreement with numerical and theoretical analysis.

Portal vein arterialization in liver transplantation: an option to restore arterial flow: a case report

We report a 66-year-old woman who underwent emergency orthotopic liver transplantation due to acute liver failure. The donor's liver graft displayed extensive arteriosclerosis, involving the celiac trunk and hepatic artery. Arterial revascularization of the graft could not be achieved, requiring an arterioportal shunt between the gastroduodenal artery and the portal vein of the recipient. During the early postoperative period, the patient's clinical condition and liver function tests improved rapidly; the patient was discharged on postoperative day 30. Two months later, she developed acute cholangitis. Ischemic-type stenosis of the intrahepatic biliary tree was present, so successful elective retransplantation was undertaken at the ninth postoperative month. In our experience, portal vein arterialization may be useful as a bridging therapy in extreme situations.

[Hepatic hydatidosis. Radical vs. conservative surgery: 22 years of experience]

OBJECTIVES

the incidence of hepatic hydatidosis has remarkably decreased in the last years due to the preventive measures adopted to stop the transmission of the parasite. However, surgery carries on being the treatment of choice, although the surgical procedure is still a matter of controversy. The aim of the study was to evaluate the results obtained with the treatment of this condition after two decades according to surgical procedure type.

MATERIAL AND METHODS

from 1983 to 2005, 372 patients were operated on for hepatic hydatidic cyst in Hospital Ramón y Cajal. Radical surgery was performed for 162 (43.5%) and conservative surgery for 210 (56.5%).

RESULTS

average postoperative hospital stay (8.65 vs. 14.9 days), morbidity (13.3 vs. 31.4%, p < 0.001), and mortality (0 vs. 3.8%, p < 0.01) were lower in the radical surgery group. Recurrence rate was 1.85% after radical surgery versus 11.9% in the conservative surgery group (p < 0.0001).

CONCLUSION

radical surgery is associated with lower morbidity, mortality, postoperative hospital stay, and recurrence rates, and represents the treatment of choice for hepatic hydatidosis. However, its indication must depend on the patient characteristics, cyst anatomy, and surgical team experience.

Accuracy of magnetic resonance cholangiography in the evaluation of late biliary complications after orthotopic liver transplantation

INTRODUCTION

The aim of our study was to evaluate the role of magnetic resonance cholangiography (MRC) in the diagnosis of late biliary complications after orthotopic liver transplantation (OLT) and to assess the diagnostic accuracy of this imaging technique.

MATERIALS AND METHODS

Seventy-one MRC were performed in 46 OLT patients with suspected biliary complication after T-tube removal. We used a fat-suppressed three-dimensional turbo spin-echo sequence (TR/TE 1800/700, ETL 100) with a 1.5-T magnet. The images and maximum intensity projections were evaluated by two radiologists. Diagnostic confirmation was obtained with percutaneous transhepatic cholangiography (PTC) (n = 10), endoscopic retrograde cholangiography (ERC) (n = 24), surgery (n = 5), and clinical and ultrasound follow-up (n = 30).

RESULTS

The MRC studies were considered diagnostic by the two radiologists in 69 cases (97.2%). MRC had a sensitivity of 93%, a specificity of 97.6%, a positive predictive value of 96.3%, a negative predictive value of 95.2%, and a global diagnostic accuracy of 95.6% to detect late biliary complications in OLT patients. The interobserver agreement was excellent (kappa = .92).

CONCLUSION

MRC is a reliable technique to detect and exclude late biliary complications after OLT.

Variability of MELD Score During the Year Before Liver Transplantation

Model for end-stage liver disease (MELD) score is a good parameter to establish the patient survival before liver transplantation and give priority to the sickest patients. The aim of this study was to evaluate the variability and potential regression of MELD score during the months before liver transplant. From the 350 patients waitlisted for transplantation, we evaluated the 124 patients who had enough blood tests during 12 months before the final event (transplantation, death, removal from list due to improvement or worsening). We considered month 12 as the final event and blood tests from 0, 3, 6, and 12 months were analyzed. MELD score was calculated and compared using ANOVA for repeated measures test. To determine variability of MELD and its components, intraclass correlation coefficient (ICC) was calculated for 0, 3, and 6 months. The degree of constancy was defined by proximity of ICC to 1. Two groups by initial MELD (< or =17 or >17) were considered. Patient data are: mean age, 53 +/- 9 years; sex: 70% men, etiology, 28% hepatitis C, 11% alcohol and hepatitis C, 16% alcohol, 28% hepatocellular carcinoma, 6% hepatitis B, 11% others; Initial Child-score, 8.5 +/- 2.0; Initial MELD score, 15.2 +/- 4.9; mean time on waiting list, 8.1 +/- 5.7 months. MELD score from 6 and 12 months was significantly higher than the initial one. The most constant parameter was creatinine (ICC:0.89); bilirubin (ICC:0.58) and INR (ICC:0.59) were the most variable ones. MELD score ICC was 0.79. In only one patient did MELD score decrease 5 points below the initial one. For initial MELD < or = 17 and >17, variability was lower in the former. In conclusion, MELD became significantly higher 6 months after the basal determination. This score is reliable as it does not tend to decrease in time. In high MELD scores (>17), 3-month survival was lower and variability greater so that more careful follow-up and prioritizing are needed.

[Results of an intestinal transplantation program in Spain. Five years later]

BACKGROUND

More than two thirds of all intestinal transplantations (ITx) performed around the world correspondent to recipients younger than 18.

OBJECTIVE

To analyze our 5-year experience in pediatric ITx.

PATIENTS

We assessed the outcome of the 19 children included in list out of 41 patients considered for ITx from 1997. The main cause of intestinal failure was short bowel syndrome (14) followed by intestinal motility disorders (3) and congenit disorders of intestinal epithelium (CDIE) (2). The median of age, at the moment of including in the list, was 0.9 years (range 0.4-17) and median of weight was 6.4kg (range 0.4-29.3). Ten children were included for liver and small bowel transplantation (LSBTx), 7 to isolated small bowel (SBTx), and 2 for multivisceral transplantation (MVTx). Indications for SBx were hepatic fibrosis/cirrhosis (10), hepatic fibrosis in evolution (5) (to avoid later LSBTx), intractable diarrhoea (1), recurrent line infections (1), lost of central vein access (1), and bad quality of life in one.

RESULTS

Five children died in the waiting list, after a median time of 325 days (range 19-581). Seven remain in the waiting list (median 139 days, range 30-778). In 3 of these the indication changed from SBTx to LSBTx because of progression to end stage liver disease. Six children recieved seven grafts (1 MVTx, 4 LSBTx, 2 SBx) after a median time in the waiting list of 352 days (range 66-732). Six out of seven grafts achieved normal function and all survivals reached full digestive autonomy after Tx. We had to rejection episodes, one with good response to medical treatment and one that required removal of intestinal allograft and later LSBTx. Two children died 1 because of problem not related to the procedure (hemorrage following liver biopsy) and one girl died 29 months after transplant due to post-transplantation lymphoproliferative disease.

CONCLUSIONS

ITx is a realistic alternative in our country for children with intestinal failure. The main problems are immunologic (rejection, lynphoproliferative and disease) Shortage of small weight donors is a dramatic limitation that prompts the discussion of surgical alternatives.

Pediatric living donor liver transplantation

AIM

The aim of this study was to analyze the results of living donor in a pediatric liver transplantation program.

PATIENTS

Twenty-six living donor liver transplantations were performed in children from 0.5 to 14.8 years of age. The main indication was biliary atresia (72%) followed by tumors (2 hepatoblastomas and 1 hepatocarcinoma). Left lateral segments were used in 23 (1 transformed into a monosegment), 1 left lobe was used in 1, and right lobes were used in 2. Arterial reconstruction employed saphenous venous grafts in the first 3 cases and end-to-end anastomoses with a microsurgical technique in the following 22 cases.

RESULTS

There has been no major morbidity in the donors, with a median hospitalization of 6 days. Four grafts have been lost; 2 in the first 3 cases. In only 1 case, the graft loss was related to the procedure saphenous venous graft thrombosis). Early biliary complications were frequent (23%). Six month, 1 year, and 5 year graft and patient survival rates were 91%, 85%, and 85% and 100%, 96%, and 96%, respectively.

CONCLUSIONS

Living donor liver transplantation is an excellent option for transplantation in children.

[Activity of a pediatric intestinal transplantation program in Spain]

AIM

To analyze the outcome of children with intestinal failure (IF) included as candidates for intestinal transplantation (IT). Patients, Eight out of 23 children with IF assessed since July 1997 met criteria for IT and were included on the waiting list. The causes of IT were Short Bowel Syndrome (SBS) in 6 and Microvillus Inclusion Disease (MID) in 2. The indication of IT were end stage liver disease (ESLD) in 5 (related to total parenteral nutrition administration, TPN), progressive hepatic fibrosis in 2 and loss of venous access in 1. The patients with ESLD were included for combined liver-small bowel transplantation (LSBT) and the remaining for isolated intestinal transplantation (IIT).

RESULTS

Two children died waiting for LSBT, 4 patients are on the waiting list, 2 for LSBT and 2 for IIT (length of stay: 4-11 months). Two children were transplanted, one with IIT in a 2.5 years old boy with MID, and one with LSBT in a 22 months girl with SBS and ESLD. Both patients recovered intestinal function after transplantation and are a live (follow-up of 19 and 10 months respectively). The LSBT's patient is under treatment for postransplant lymphoproliferative disease (PTLD).

CONCLUSIONS

The lack of suitable donors for the small children candidate to IT explains the long period of stay on the waiting list and the high pretransplant mortality. Two strategies are possible; early referral of children with IF to a transplant center and surgical techniques like ex vivi-hepatic reductions of the LSB graft.

Management of biliary duct confluence injuries produced by hepatic hydatidosis

From 1978 to 1999 a total of 850 patients underwent surgical treatment for hydatid disease of the liver at our surgical department. Biliary duct confluence injuries produced by hepatic hydatidosis (HH) were founded in six patients (0.7%). Surgical intervention was undertaken to relieve the obstructive jaundice and clinical manifestations of cholangitis and to treat the hydatid cyst. A partially open cystopericystectomy technique was used in three patients with a double bilioenteric Roux-en-Y reconstruction. The remaining three patients (two with prehepatic portal hypertension and one with triple hepatic duct confluence) were subjected to a cystojejunostomy. There were no hospital deaths. Two cases of anastomotic leakage following a high bilioenteric anastomosis occurred but did not require surgical treatment. During the follow-up (5-19 years) one patient suffered local recurrence of the hydatid disease 7 years after cystojejunostomy. The site of intrahepatic biliary and vascular involvement, the presence of biliary duct anomalies, and the presence of portal hypertension are decisive factors when choosing the "ideal" procedure for reconstruction. Conservative surgical approaches (partial cystectomy and cystojejunostomy) are the treatments of choice. Radical surgery is often a serious matter.

Preservation of the recipient inferior vena cava in liver transplantation

Twenty piggy-back (PB) liver transplantations (LT) were compared with 20 LT performed by the standard technique in order to evaluate whether or not the theoretical haemodynamic advantages of the preservation of the inferior vena cava (IVC) have any impact on the final results of the LT. Statistically significant differences were observed in the duration of the hepatectomy, which was longer for PB LT (192 min vs. 146 min), and in the duration of the anhepatic phase, which was shorter in that group (52 min vs. 76 min). There were no differences in the duration of the complete surgical procedure, consumption of blood products, incidence of postoperative acute renal failure, number of reoperations or survival.

Aspergillus antigenemia sandwich-enzyme immunoassay test as a serodiagnostic method for invasive aspergillosis in liver transplant recipients

BACKGROUND

Invasive aspergillosis (IA) is an important cause of mortality in liver transplant patients. Clinical and microbiological diagnosis is difficult, and it is frequently achieved only after autopsy. Early diagnosis and antifungal therapy could improve the survival of these patients.

METHODS

A retrospective case-control study of IA in liver transplant recipients (OLT) was performed to determine the value of the detection of galactomannan Aspergillus antigen in serum using a sandwich-ELISA test (Platelia, Sanofi Diagnostic Pasteur). Stored frozen serum specimens obtained during the posttransplantation period were used.

RESULTS

Fourteen cases of IA were diagnosed in 240 OLT recipients (IA incidence: 5.8%) during 5 years with 13 deaths (mortality: 93%). Nine case patients and 33 control patients met the criteria required for being considered "valid" for antigenemia analysis. In five of the nine case patients, a serum sample was positive for Aspergillus antigenemia detection. The median value was 5.7 ng/ml (range: 1.6-6.6). Sensitivity of the test was 55.6%, specificity was 93.9%, the positive predictive value was 71.4%, and the negative predictive value was 88.6%. The likelihood ratio of a positive test was 9.2.

CONCLUSIONS

Galactomannan detection in serum could be useful for an early diagnosis of IA in OLT recipients.

[Intestinal transplantation. First experience in Spain]

We present the first case of intestinal transplant (IT) performed in Spacin.

CASE REPORT

28 months old boy with secretory diarrhea since the first month of life, diagnosed of microvillous inclusion disease (MID). He is on total parenteral nutrition (TPN) and had suffered of multiple episodes of catheter related sepsis with lost of standard venous access. An isolated small bowel transplant from a cadaveric donor was performed at the age of 3 years. The native ileocaecal valve and colon were not removed.

RESULTS

Enteral feeding was started in the 2nd. week after the IT. On the 25th day he was off TPN. Since the 77th day, he eats regular foods by mouth. At the 6th month post IT the ileostomy was closed. Among the complications, he suffered a rotavirus infection on the 38th post IT day and an episode of mild rejection responsive to methil-prednisolone bolus.

CONCLUSIONS

The IT is a therapeutic option that can be already offered with possibilities of success in our country. Although the colonic enterocytes express MVD, the recipient ileocaecal valve and colon can be preserved.

Vaccination against hepatitis B virus in cirrhotic patients on liver transplant waiting list

Patients with cirrhosis may fail to respond to anti-hepatitis B vaccine. An adequate response would be especially interesting when patients are on a liver transplant waiting list. Posttransplantation de novo hepatitis B has been well documented. One possible source is the grafting of organs from hepatitis B surface antigen (HBsAg)-negative, antibody to HBsAg (anti-HBs)-positive, antibody to hepatitis B core antigen-positive donors. The achievement of high titers of anti-HBs could be protective in this setting. We studied prospectively the response rate to recombinant hepatitis B vaccine (3 40-microg doses administered at 0, 1, and 2 months) in 62 patients with end-stage liver disease awaiting liver transplantation. Twenty-two patients showed antibody response (44%). A further 3 doses were administered in 15 of 28 nonresponders and were effective in 9 patients. Thus, the response rate reached 62% (31 of 50 patients completing 1 or 2 vaccination schedules before liver transplantation). Classic hepatitis B vaccination studies of patients with cirrhosis yield lower response rates. Vaccination with this double-dose schedule should be considered in such patients before liver transplantation.

The role of multimodality therapy for resectable esophageal cancer

BACKGROUND

There is an increasing interest in the role of combined therapy to achieve long-term survival for patients with resectable esophageal neoplasms. Surgery provides excellent palliation with relatively low morbidity and mortality rates, but cure remains elusive.

MATERIAL AND METHODS

From January 1988 to January 1998, a total of 137 patients met eligibility criteria for a combined multimodal therapy, prospective, nonrandomized protocol of induction chemoradiation therapy followed by surgical resection, based on radiological and endoscopic assessment of the extension (all patients were initially considered to be at clinical stages I to III, locoregional). Consequently, patients with high grade Barrett's dysplasia or any squamous carcinoma in situ (stage 0) and those with distant metastatic disease (stage IV) were excluded. Among this group, 48 operable patients with biopsy-proven esophageal cancer finally entered and completed the protocol and are the sample of the present study. Multivariate logistic regression models were used to identify risk factors for death or recurrence. Actuarial survival was calculated since the beginning of the induction protocol by the Kaplan-Meier method, and comparisons between groups were made by the log-rank test.

RESULTS

Mean age was 61.6 (range 45 to 71), and 72.9% were male. The majority of the tumors (70.8%) were located at the lower third/cardia and as many as 18.8% were adenocarcinoma. After a mean of 7.5 weeks (range 5 to 12) after the completion of the induction phase, 68.7% underwent a transthoracic esophagectomy and 31.3% a transhiatal esophagectomy. The in-hospital mortality rate was 10.4% (5 patients). A complete response (no evidence of tumor within the specimen: pT0) was achieved in 25% (12 patients). After a mean follow-up of 20.2 months, mean survival for the entire group was 18.2 months (95% confidence interval 14 to 22). At the end of the study, 25% (12) remained alive. Actuarial survival rates at 12, 23, and 37 months were 56.2%, 36.9%, and 21.9%, respectively.

CONCLUSIONS

Esophageal resection after induction therapy seems to be related to a slightly higher mortality rate compared with historical series, and for this reason, neoadjuvant therapy must be considered still experimental. However, no statistical significant difference in survival is showed in those cases with complete pathological response (pT0). Factors influencing survival are recurrence and age. Surgery alone remains the standard therapy for esophageal cancer.

Bilateral gluteoplasty for fecal incontinence

PURPOSE

This study describes our clinical experience with adynamic bilateral gluteoplasty in 20 patients with total fecal incontinence, in whom a sphincter repair had failed (n = 17) or was nonviable.

METHODS

Between 1986 and 1995, 12 women and 8 men ranging in age from 15 to 58 (mean, 37) years underwent different techniques of adynamic gluteoplasty. The indications for the operation were congenital anomalies, denervation, or sphincter destruction. Postoperative evaluation was clinical (Pescatori grading; self-evaluation) and manometric.

RESULTS

Morbidity was only related to wound infection (n = 7) requiring late reoperations for neosphincter repair (n = 5), anal stenosis (n = 2), and incisional hernia after colostomy closure (n = 1). Two other patients with no complications also had further surgery for tightening of the neosphincter; they had a successful outcome. Of the 17 evaluable patients, 9 (53 percent) achieved normal control or were graded as Pescatori A-1, A-2, B-1, or C-1, 1 (6 percent) as Pescatori C-2, and 7 (41 percent) as Pescatori C-3. Six patients (35 percent) judged their results as excellent, three (18 percent) as good, one (6 percent) as fair, and seven (41 percent) as bad. Eight patients are able to retain 200 ml of water instilled into the rectum for between five minutes and two hours. For the nine patients with better results, the mean +/- standard deviation of the differences between postgluteoplasty and pregluteoplasty anal pressures were 40 +/- 25 mmHg (resting pressure) and 122 +/- 85 mmHg (squeeze pressure). These findings demonstrate a tonic and voluntary activity of the plasty. The author's technique has less morbidity, and excellent or good results were achieved in 67 percent of the patients. Failures were attributable to suture disruption (n = 4), poor muscular contraction (n = 2), and intractable constipation (n = 1).

CONCLUSIONS

Adynamic gluteoplasty is efficient for achieving good or very good continence status in a higher proportion of patients than with other adynamic muscle transfer procedures.

Selection of Candida glabrata strains with reduced susceptibility to azoles in four liver transplant patients with invasive candidiasis

The cases of four liver transplant recipients who developed invasive candidiasis (2 cholangitis, 1 perihepatic abscess, 1 candidemia) due to azole-resistant, Candida glabrata are reported. Three patients were receiving azolic compounds (2 itraconazole, 1 fluconazole) when the infection was diagnosed. All four patients received fluconazole as intestinal decontamination during the first three weeks post transplantation. The infections occurred two months after transplantation in all patients, and in one patient Candida infection was the direct cause of death. Infection of the biliary tree was the origin of candidiasis in three patients; the fourth patient developed neutropenic-related candidemia. Fluconazole MICs exceeded 16 micrograms/ml in all cases; itraconazole MICs were 16, 2, 1, and 2 micrograms/ml, respectively. The potential role of Candida species other than albicans in these patients after administration of azole agents is discussed.

[The ultrashort bowel syndrome: the surgical treatment of an exceptional case]

An exceptional case of a 16-year-old boy who accidentally lost all of the small bowel (except the proximal 5 cm. of jejunum), and also 10 cm of transverse colon and a small part of the middle and upper rectum, is presented. After suffering severe medical complications derived from prolonged and uninterrupted total parenteral nutrition for more than one year, with no oral intake except fluids, the patient underwent intestinal lengthening of all the residual bowel up to the sigmoid colon, with antiperistaltic anastomosis and sigmoid J pouch with myotomy. Several months after the operation the patient returned to his normal activities and is fed with a free-diet, complemented or not with nocturnal enteral and parenteral feeding, depending on the circumstances and weight variations. Lengthening of the large bowel together with the rest of surgical gestures here performed has not been published previously.

[Ileoanal anastomosis with a J reservoir. The evolution of the technic and the results]

Beginning 1982, our group has been performing the technique of ileal pouch-anal anastomosis, changing the procedure for achieving better functional results, less morbidity and making it easier. Fifty patients operated on for ulcerative colitis and "polyposis coli" were grouped as follows: Group I (28): proctocolectomy, mucosectomy, handsewn anastomosis and temporary ileostomy; Group II (13): proctocolectomy without mucosectomy, leaving a rectal stump up to just the level of the puborectalis, instrumental anastomosis and no-ileostomy; Group III (9): Same as Group II but with the implant of an endoluminal prosthesis to defunction the pouch. From our results it is concluded that, provided an adequate selection of patients is done, the best technique is the one performed in Group III due to its simplicity, no morbidity related to the ileostomy, no risk of fistula and probably better functional results than in Group II.

Effects of long-term monounsaturated- vs polyunsaturated-enriched diets on lipoproteins in healthy men and women

The effect of dietary-fat saturation on plasma lipoprotein concentrations was assessed in 46 men and 32 women placed on a diet enriched in polyunsaturated fatty acids (sunflower oil) for 12 wk and, under isocaloric conditions, on a diet enriched in monounsaturated fatty acids (olive oil) for the next 16 wk in men and 28 wk in women. Fat comprised 37% of the total energy intake in men and 36% in women. At the end of the monounsaturated fatty acid diet no change occurred in total cholesterol (TC) in men but it increased by 9% in women. High-density-lipoprotein (HDL) cholesterol increased by 17% in men and by 30% in women. The atherogenic index (TC:HDL cholesterol) fell significantly in both sexes. No significant changes occurred in plasma low-density-lipoprotein cholesterol or in total triglycerides values. These data show that when compared with polyunsaturates, monounsaturates increased HDL cholesterol and reduced the atherogenic risk profile in both sexes.

Total fecal incontinence--a new method of gluteus maximus transposition: preliminary results and report of previous experience with similar procedures

Since 1986, different procedures of gluteus maximus transposition have been performed, by one of the authors, in 10 patients with total anal incontinence not amenable to sphincter repair, due to congenital anomalies (four), sphincteric denervation (three) or after severe trauma (three). Variable degrees of long-lasting fecal control were obtained in all but one patient, with great improvement in six. Difficulties for achieving a closed anus without muscular tension of the neosphincter, together with the morbidity associated with anal wound infection, determined the reasons for the successive use of different techniques (Biström, Hentz, Schoamaker) until the authors, in 1990, designed a new procedure (Devesa). Although the reported experience with this technique described here is limited to only four patients, our impression is that the method is easier, has less morbidity, and achieves better short-term functional results, derived from a thick, tension-free neosphincter.