Analysis of the feed-forward method for the referencing of a CW laser to a frequency comb.

We report on a comprehensive theoretical and experimental analysis of the feed-forward method for external frequency stabilization of a continuous wave laser against a frequency comb. Application of the method to a distributed feedback diode laser at 1.55 µm allows line narrowing from 800 to 10 kHz, with frequency noise reduction by more than 2 decades up to a Fourier frequency of 100 kHz and a maximum control bandwidth of 0.8 MHz. The results are consistent with a relative phase fluctuation of 1.4 rad rms, as limited by uncompensated high-frequency noise of the slave laser.

Wide-bandwidth phase lock between a CW laser and a frequency comb based on a feed-forward configuration.

Wide-bandwidth phase lock between the tooth of a frequency comb and a CW extended-cavity diode laser at 1.55 µm is achieved by the use of an acousto-optical frequency shifter in a feed-forward configuration. The coherence properties of the comb are efficiently transferred to the CW laser, whose linewidth is narrowed down to the ∼10 KHz comb level. A maximum control bandwidth of ∼0.6 MHz has been experimentally achieved, limited by the transit time of the acoustic wave inside the frequency shifter.

Variation among endoscopy units in the achievement of the standards of colonoscopic performance indicators.

BACKGROUND/AIMS: To assess the achievement of quality standards of colonoscopy at six endoscopy units. METHODOLOGY: Three indicators were used to assess the quality of 1056 colonoscopies performed at six hospitals: cecal intubation; adequate colon cleansing; and removal and recovery of all detected polyps. Analyses were performed on the total number of colonoscopies and on colonoscopies in which polyps were actually detected. The accomplishment of each indicator and a global compound index of all three indicators, named the Problem Rate, were analyzed. Results from each endoscopy unit were compared to previously established standards. RESULTS: Adequate colon cleansing was the most frequent problem for quality in all centers; adequate colon preparation was 67% (range 50 to 84%). The cecum was reached in 84% of all colonoscopies (range 76 to 90%). 75% of all patients (range 28. 79%) had all polyps excised and recovered. All centers had rates below standard for one or several indicators (p<0.01, all cases). Two of the participant hospitals had an overall problem rate above the estimated standard (p<0.01). CONCLUSIONS: There is a significant variation in the achievement of quality standards of colonoscopy between endoscopy units. Colon cleansing is the most frequent quality problem for colonoscopy.

Two metallocarboxypeptidase inhibitors are implicated in tomato fruit development and regulated by the Inner No Outer transcription factor.

The TCMP-1 and TCMP-2 genes of tomato code for metallocarboxypeptidase inhibitors and show sequential, tightly regulated expression patterns during flower and fruit development. In particular, TCMP-1 is highly expressed in flower buds before anthesis, while TCMP-2 in ripe fruits. Their expression pattern suggests that they might play a role in fruit development. Here, to investigate their function, we altered their endogenous levels by generating transgenic plants harbouring a chimeric gene expressing the TCMP-1 coding sequence under the control of the TCMP-2 promoter. The expression of the transgene caused an earlier fruit setting with no visible phenotypic effects on plant and fruit growth. The altered TCMP-1 regulation determines an increased level of TCMP-1 in the fruit and unexpected changes in the levels of both TCMPs in flower buds before anthesis, suggesting a mechanism of transcriptional cross-regulation. We in silico analysed TCMPs promoter regions for the presence of common cis acting elements related to ovary/fruit development and we found that both promoters contain putative binding sites for INNER NO OUTER (INO), a transcription factor implicated in ovule development. By chromatin immunoprecipitation, we proved that INO binds to TCMP-1 and TCMP-2 promoters, thereby representing a candidate regulatory factor for coordinated control of TCMPs.

[Revision of obstructive sleep apnea syndrome in the child]. / Revision del síndrome de apnea obstructiva del sueño en el niño.

The obstructive sleep apnea syndrome (OSAS) is frequent in infancy and childhood. It is caused by a prolonged upper respiratory airway obstructioon during sleep, and adenotonsillar hypertrophy is the most important cause. OSAS may have an impact on physical and cognitive development, but syntoms in children are subtle and may pass unrecognised. Polysomnography is the gold standard technique for OSAS diagnosis and surgical approach with adenotonsillectomy is the most frequently treatment indicated. Early diagnosis and treatment and adequate follow up are important to prevent physical disturbances secondary to chronic hypoxemia and to avoid cognitive deficits associated with disrupted sleep architecture.

Endoscopic sclerotherapy versus oesophageal transection in the prevention of variceal rebleeding.

OBJECTIVE: To compare sclerotherapy with oesophageal transection in the prevention of rebleeding in patients with oesophageal varices. DESIGN: A prospective trial. PATIENTS: Forty-one patients with cirrhosis and variceal bleeding. METHODS: After recovering from an acute episode of oesophageal variceal bleeding patients were randomized into two groups. One patient was excluded. Twenty-two patients were treated with sclerotherapy (group 1) and 18 underwent an oesophageal transection (group 2), with a shorter elapsed time from randomization to treatment in group 1. Both groups were similar with regard to clinical and biochemical features and variceal size. Failure, defined in group 1 as rebleeding or incomplete eradication after four sclerotherapy sessions, occurred in five (22.7%) patients; in group 2, rebleeding occurred in two (11.1%) patients (no statistically significant difference). CONCLUSION: Although the survival rate was similar in both groups, sclerotherapy is preferable to oesophageal transection because it requires a shorter duration of hospitalization and has fewer complications.

The colon as oesophageal substitute in non-malignant disease. Long-term clinical results and functional studies.

Between 1974 and 1987, we performed 18 left colonic interpositions for benign oesophageal disease: caustic lesions in 6 patients, undilatable reflux stenosis in 5, reoperative peptic strictures in 5, penetrating wound in 1 and iatrogenic stricture following oesophagogastric transection for bleeding in 1. Four patients were women. The mean age was 40 +/- 19 years. In 10 patients a left thoracotomy was used; in the other 8 a cervico-abdominal approach was employed. One patient died postoperatively from liver failure. The mean follow-up was 11 +/- 4 years. Clinical results were excellent or good in 12 of the remaining 17 patients (71%). These results varied according to the length of colon interposition; in patients with long colonic interposition, poorer results were achieved. The motor activity of the colonic transplant was evaluated by manometric studies. After intraluminal injection of 30 ml of liquid, the colon responded uniformly with sequential peristaltic waves. Transmission of the oesophageal waves through the oesophagocolic anastomosis was studied in 2 patients. After wet swallows, the oesophageal contractile waves were followed by colonic waves. Solid radionuclide colonic transit studies were carried out in 18 control subjects and in 18 patients with colon interposition. In subjects with a normal oesophagus, the general pattern was rapid emptying of the bolus through the oesophagus. Findings in patients with a short transplant were similar to those observed in normal oesophagi. In most patients with long transplants the transit was abnormal.(ABSTRACT TRUNCATED AT 250 WORDS)

Ischemic colitis attributable to a cleansing enema.

A 42-year-ole woman developed ischemic colitis shortly after the administration of a cleansing enema. As possible predisposing factor in out patient we assess treatment with contraceptives by parenteral route, started one year before her episode of bowel ischemia. To out knowledge, this is the first patient without underlying pathology with proven ischemic colitis secondary to a cleansing enema.

PIP: A 42-year-old woman was administered a cleansing enema to treat chronic constipation. Immediately after the procedure she developed intense pain in the abdominal region, nausea, vomiting, and rectal bleeding. The patient, who was in good general health, had been on contraceptive administration of Depo-Provera (150 mg each month) for 1 year. Radiological investigation, endoscopy and histopathological examinations revealed acute ischemic colitis. A left hemicolectomy was performed with colorectal anastomosis through laparotomy; the postoperative period was good and the patient was discharged in good health. The majority of cases of ischemic colitis occur in persons of advanced age, because of arteriosclerosis. In young female patients it is necessary to systematically investigate contraceptive use as a possible iatrogenic cause; surgery may be indicated in some cases.

Transtympanic gentamicin in the treatment of Meniére's disease.

Aminoglycosides enable a pharmacological approach, before resorting to surgery, to the treatment of Menière's disease (MD) proving unamenable to routine medical treatment. The staging of MD is an essential preliminary step in the implementation of a specific and personalized treatment with transtympanic gentamicin. The ideal condition is the presence of endolymphatic hydrops with little or no damage to the cochlear and vestibular hair cells. The technical aspects of the method are discussed. In 21 patients with unilateral Menière's disease in various stages, this treatment achieved the regression of vertigo in 86% of cases; hearing was better in 19% of cases, preserved in 62% and worse in 19%; tinnitus regressed totally or partially in 62% of cases; aural fullness also regressed totally or partially in 57% of cases.

[Endoscopic prosthesis insertion in the palliative treatment of malignant esophageal stenosis. (Endoscopic esophageal prosthesis)]. / Inserción endoscópica de prótesis en el tratamiento paliativo de las estenosis esofágicas malignas. (Endoprótesis esofágica endoscópica).

We report our experience with endoscopic esophageal prosthesis in the treatment of 82 patients with advanced malignant oesophageal stenosis. The cause of the stenosis was an esophageal or esophagogastric cancer in 75 cases and a bronchogenic cancer in 7 patients. In 18 cases a tracheobronchial fistula was also present. A silicone tube (Atkinson) was used in 58 patients, a polyvinyl tube (Wilson-Cook) in 22 cases and a self-expanding tube in the remaining 2 patients. There was no technical failure in the insertion of the prosthesis. A normal feeding was possible in 71 of the 82 patients (86%) within 48 after the intubation. Major complications occurred in 8 cases (9.7%), 4 patients with esophageal perforation and 4 cases with aspiration bronchopneumonia. Postoperative mortality rate was 7.3%, one patient with perforation, 3 cases with aspiration bronchopneumonia and 2 patients with sepsis. The prosthesis partially displaced in 9 cases, but could be endoscopically replaced in all of them. The displacement of the prosthesis was complete in 3 patients, one of which needed a surgical procedure to remove the tube. The prosthesis was bunged up by a solid meal bolus in 4 cases, but an endoscopic procedure was successful in removing the bolus. Therapy with laser was necessary in two cases with self-expanding prosthesis obstructed by tumoral growth. We conclude that, in malignant esophageal stenosis, the endoscopic implantation of esophageal endoprosthesis is an effective, cheap and relatively safe palliative therapeutic alternative with a low postoperative mortality rate.

[Carcinoma of the esophagus. Palliative treatment with endoscopic prosthesis]. / Carcinoma de esófago. Tratamiento paliativo con endoprótesis endoscópica.

The efficacy and safety of endoscopically inserted esophageal prosthesis was evaluated in 33 patients with non-operable carcinoma involving the esophagus. In 30 cases, the origin of the tumor was esophageal, and in 3 cases, bronchopulmonary. Esophago-pulmonary fistula was present in 9 patients. Histologic exam of the tumors revealed 11 adenocarcinomas and 22 epidermoid carcinomas. In every case, Atkinson prosthesis was used and previous esophageal dilatation was needed in 21 patients. Normal oral feeding was achieved in 29 patients. Mean hospital stay after insertion of the prosthesis was 5 days. Survival rate was 84.8% at one month, 63.6% at 4-6 months, 42.4% survived more than 6 months, and 21.2% were still alive one year after the procedure. Complications occurred in 3 patients (9%) -esophageal perforation in two cases, and pneumonia in one case. One patient died. In conclusion, in patients with advanced carcinoma involving the esophagus, palliative therapy with endoscopically inserted esophageal prosthesis is effective, relatively safe and cheap.

[Combined endoscopic treatment with extracorporeal lithotripsy in chronic calcifying pancreatitis]. / Tratamiento endoscópico combinado con litotricia extracorpórea en la pancreatitis crónica calcificante.

In the management of severe chronic pancreatitis, a variety of new endoscopic methods have been proposed as an alternative to traditional surgery. The main goal of these procedures is the remission of pain. They include pancreatic endoscopic sphincterotomy with subsequent endoscopic extraction, which can be associated to extracorporeal shock-wave lithotripsy for stone desintegration before removal of large calculi, and to the insertion of a pancreatic stent in case of a pancreatic duct stricture. We present two cases of severe chronic pancreatitis managed successfully with this endoscopic treatment.

[Results of endoscopic dilatation treatment of benign esophageal stenosis]. / Resultados del tratamiento dilatador endoscópico en las estenosis esofágicas benignas.

The management of benign esophageal stenoses is based on endoscopic dilatation of the tight segment for the remission of dysphagia. Five hundred and twenty sessions of dilatation with Savary-Guilliard bougies have been performed in one hundred and twenty-nine patients with benign esophageal stenoses. Patients with peptic stenoses (n = 59) needed a lesser number of sessions (mean: 2.47) than patients with postsurgical (n = 44; mean: 4.86) or caustic (n = 18; mean: 7.77) stenoses. The treatment failed in 4 patients (3.2%) and severe complications were observed in 3 patients (2.4%). These results support the efficacy and safety of this technique.

[Early complications of pneumatic dilatation in the treatment of primary motility disorders of the esophagus]. / Complicaciones precoces de la dilatación neumática en el tratamiento de los trastornos motores primarios del esófago.

We analyze the incidence and evolution of the early complications of 96 consecutive patients with primary esophagus motor disorders, treated with pneumatic dilatation under endoscopic control (1.4 sessions per patient). In 4 (0.042/patient, 0.029/dilatation) patients the esophagus was perforated; the diagnosis was made in the first 24 hours; pneumomediastinum was a constant finding in the radiological exploration. In three cases the complication was suspected because of the apparition of sustained thoracic pain after the dilatation maneuver and in one case the presentation symptom was bleeding of cardial mucosa, larger than usual, at the end of the dilatation. The four patients evolved favorably with conservative treatment (avoidance of oral food intake, gastroesophageal aspiration, antibiotic therapy and parenteral nutrition).

[Prevalence of gastroesophageal reflux in patients with primary motor disorder of the esophagus treated with endoscopic pneumatic dilatation]. / Prevalencia de reflujo gastroesofágico en pacientes con trastorno motor primario del esófago tratado mediante dilatación neumática endoscópica.

The prevalence of gastroesophageal reflux after successful pneumatic dilatation was investigated in 30 patients with primary esophageal motor disorder. After a median follow-up period of 377 days, three patients presented symptoms of acid reflux and five patients had endoscopic esophagitis (grade I, 3 patients; grade II, one patient; and grade III, one patient). Ambulatory 24 hr. esophageal pH monitoring was positive in 20% and 30% of the patients compared to our normal values and to those from other series from the literature, respectively. The concordance between pH results and symptoms and/or endoscopic esophagitis was very low. It is concluded that 24 hr. esophageal pH monitoring is frequently abnormal after pneumatic dilatation, but its clinical significance is low, because very few patients have symptoms and/or severe esophagitis.

Diagnostic value of symptoms in patients with suspected upper digestive tract disease.

OBJECTIVE: to develop a predictive model based on clinical data for patients with suspected upper digestive tract disease. PATIENTS AND METHODS: forty-seven clinical data were obtained before endoscopy from 283 patients with suspected upper digestive disease (153 men; mean age 55 years, limits 17-92 years). A clinical prediction of diagnosis was made before endoscopy. On the basis of the endoscopic findings, the patients were divided into three diagnostic groups: absence of significant disease (group I), significant benign disease (group II) and malignant disease (group III). The probability rate of belonging to each one of the three groups was obtained for each patient by using Bayes' theorem. RESULTS: the endoscopic findings were classified according to their clinical importance: 121 patients (43%) belonged to group I, 137 (48%) were included in group II; and 25 (9%) in group III. The clinical prediction correctly classified 61% of the patients (group I: 56%, group II: 62% and group III: 76%) The coincidence between prediction obtained using Bayes' theorem and the actual diagnosis was 61% (group I: 65%, group II: 51%, group III: 92%). The predictive model was useful to confirm or not the clinical prediction. CONCLUSION: objective analysis of clinical data can be useful to support clinical judgment, mainly in patients with neoplasia. However, the model is not adequate to improve indication of upper endoscopy since many patients are misclassified.

[Candida esophagitis and cytomegalovirus gastritis: optic and immunohistochemical diagnosis in an HIV+ patient]. / Esofagitis moniliásica y gastritis por citomegalovirus: diagnóstico óptico e inmunohistoquímico en paciente VIH+.

Esophageal candidiasis, along with gastritis caused by cytomegalovirus--CMV--, is a common opportunistic infection in immunodepressed patients. A clinico-pathological description is made of a human immunodeficiency virus-positive female (group IV-C-2) with a history of odynophagia and dysphagia resistant to treatment. The light microscopy and immunohistochemical study of an endoscopic esophago-gastric biopsy allowed the diagnosis of moniliasic esophagitis associated with CMV-induced gastritis. Emphasis is placed on the efficacy of immunohistochemical techniques over other methods in diagnosing CMV infection.

[Comparison of the efficacy of cleaning and disinfection of videoscopes: mechanized versus manual]. / Comparación de la eficacia en la limpieza y desinfección de videoendoscopios: mecanizada frente a manual.

AIM: a) To analyze the effectiveness of the automated cleaning and disinfection of endoscopies (Olympus miniETD, not previously tested) versus the manual method; b) To evaluate the drying and storage procedures used in our unit. MATERIAL AND METHODS: Prospective 10-day study. The endoscopies were randomized for automated or manual cleaning and disinfection. Endoscopic samples were collected for microbiology studies at three points during the process: a) after endoscopy (after manual cleaning with water), b) after cleaning with enzymatic detergent and disinfection (automated or manual) and c) at the first hour in the morning. RESULTS: Sixty-five samples were collected after endoscopy: 26 from gastroscopy, 26 from colonoscopy and 13 from duodenoscopy (positive cultures were found in 22, 25 and 10, respectively). The 35 samples collected after automated disinfection were negative, as were 29 of the 30 collected after manual disinfection (p = 0.46). Sixty-four of the 65 samples were negative for hepatitis B and hepatitis C. The only sample positive for hepatitis C became negative after manual disinfection. Positive culture was found in 15% of the samples collected before beginning the session. CONCLUSIONS: a) Automated cleaning and disinfection (Olympus miniETD) are as effective as manual cleaning. b) Drying and storage procedures should be improved and/or disinfection should be carried out again before the first endoscopy of each session.

[Endoscopic treatment combined with extracorporeal shock wave lithotripsy of difficult bile duct stones]. / Tratamiento endoscópico combinado con litotricia extracorpórea con ondas de choque de la coledocolitiasis de difícil manejo.

OBJECTIVES: The aim of this study was to determine the safety and effectiveness of extracorporeal shock wave lithotripsy (ESWL) in difficult bile duct stones resistant to endoscopic extraction. PATIENTS AND METHOD: From January 1997 to February 2002, combined treatment with endoscopy and ESWL was used in 19 patients who had undergone unsuccessful endoscopic bile duct stone extraction after sphincterotomy. The procedure was carried out using analgesic and sedative drugs or deep sedation, prophylactic antibiotic therapy, and monitoring of vital signs. Bile duct stone localization was performed by contrast injection through nasobiliary drainage and fluoroscopy. After each ESWL session, lavage was performed through drainage and stone fragments were extracted endoscopically. RESULTS: The 19 patients presented high surgical risk due to advanced aged and/or concomitant diseases. All presented jaundice and pain and nine (47.3%) presented associated cholangitis. Thirty ESWL sessions were performed (1.57 sessions per patient), with a mean of 2,120 shock waves per session. In 16 of the 19 patients (84.2%), combined treatment with ESWL and subsequent instrumental endoscopic extraction achieved complete clearance of the biliary tract. The treatment failed in 3 patients who were referred for surgical treatment. No early or late complications were observed, except in one patient who presented a self-limiting febrile syndrome. CONCLUSIONS: Therapeutic endoscopy combined with ESWL is safe and effective in patients with difficult bile duct stones. It represents a therapeutic alternative in patients at high surgical risk.

[Endoscopic treatment of pancreatitis and its complications]. / Tratamiento endoscópico de la pancreatitis y sus complicaciones.

OBJECTIVES: To study the long- and short-term safety and efficacy of endoscopic treatment of pancreatitis and its complications in our environment. PATIENTS AND METHODS: We performed a retrospective analysis of 43 patients with chronic pancreatitis, acute pancreatitis complicated with pseudocyst, and pancreatic fistula diagnosed by endoscopic retrograde cholangiopancreatography who were suitable for endoscopic treatment. RESULTS: Endoscopic treatment was attempted in 35 patients. The indication for treatment was pain in 17 patients (48.5%), jaundice in 7 (20%), pseudocyst in 10 (28.5%) and suspected external fistula in 1 (3%). The technique was successfully performed in 28 (80%). Of the patients with pain, pancreatic prosthesis was inserted in 13 and extracorporeal lithotripsy was applied in 6. Sixty-five percent of the patients improved. Of the 7 patients with jaundice, all had secondary stenosis of the biliary tract. Treatment was applied in 2, who showed partial improvement. Of the 15 patients with pseudocyst, endoscopic treatment was indicated in 10; the technique was successfully performed in 8 and complete resolution was achieved in 7 (87.5%). The patient with external fistula was treated with transpapillary prosthesis and complete resolution of disruption of Wirsung's duct was achieved. Overall improvement in successfully treated patients was: complete in 19 (68%), partial in 3 (18%), no improvement in 4 (14%) and 2 patients were lost to treatment. There were 4 short-term complications. There were 4 deaths and one was related to the technique. CONCLUSIONS: Endoscopic treatment of chronic pain in chronic pancreatitis, pseudocysts and fistulas was effective in our environment with a low rate of complications.