Upgrading of solid recovered fuel (SRF) by dechlorination and catalytic pyrolysis over nanocrystalline ZSM-5 zeolite

Globally increasing concern related to municipal solid waste generation is encouraging research efforts on developing alternative routes to valorize mixed refused wastes. In this way, catalytic pyrolysis is emerging as an interesting and efficient technology due to its great flexibility in terms of feedstock. In the current work, upgrading of a Solid Recovered Fuel (SRF) has been investigated by catalytic pyrolysis over nanocrystalline ZSM-5 zeolite (n-ZSM-5), paying special attention to dechlorination effects due to the high Cl content of the raw waste. Thus, pretreatment of the SRF by water washing and mild thermal processing allows for a significant reduction of the Cl concentration. Regarding the catalytic pyrolysis step, the best conditions correspond with a temperature of 400 °C in the catalyst bed and 0.50 catalyst/SRF mass ratio, which lead to ca. 30 wt% oil yield (rich in aromatic hydrocarbons) together with about 40 wt% gas yield (rich in C3-C4 olefins). Accordingly, these products could find use as raw chemicals or for the production of advanced fuels. In addition, zeolite reutilization has been tested for several cycles, denoting a progressive modification of the products distribution because of coke deposition. However, an almost total recovery of the n-ZSM-5 zeolite catalytic performance is achieved after regeneration by air calcination, affording the production of an oil fraction with a Cl content as low as 40 ppm.

In vitro bactericidal activity of a carbohydrate polymer with zinc oxide for the treatment of chronic wounds

Introduction. Biological adhesives and effective topical therapeutic agents that improve wound healing are urgently required for the treatment of chronic ulcers. A biodegradable adhesive based on a carbohydrate polymer with zinc oxide (CPZO) was shown to possess anti-inflammatory activity and enhance wound healing, but its bactericidal activity was unknown.Aim. To investigate the bactericidal activity of CPZO against bacteria commonly present as infectious agents in chronic wounds.Methodology. We examined the bactericidal activity of CPZO against three biofilm-producing bacteria (Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa) through three strategies: bacterial suspension, biofilm disruption and in vitro wound biofilm model.Results. In suspension cultures, CPZO had direct, potent bactericidal action against S. aureus within 24 h, whereas E. coli took 7 days to be eliminated. By contrast, P. aeruginosa survived up to 14 days with CPZO. CPZO had biofilm disruption activity against clinical isolates of S. aureus in the anti-biofilm test. Finally, in the in vitro wound biofilm model, CPZO dramatically reduced the bacterial viability of S. aureus and P. aeruginosa.Conclusions. Together with its previously shown anti-inflammatory properties, the bactericidal activity of CPZO gives it the potential to be a first-line therapeutic option for chronic various ulcers and, possibly, other chronic ulcers, preventing or controlling microbial infections, and leading to the healing of such complicated chronic ulcers.

A new biodegradable adhesive for protection of intestinal anastomoses. Preliminary communication

BACKGROUND AND AIMS

Anastomotic leaks continue to be a devastating complication for patients and surgeons worldwide. The few surgical adhesives available to date have not achieved the desired clinical results. The purpose of this experimental study was to determine if Pebisut® applied to intestinal suture lines provides increased resistance and protection during the critical days of healing.

METHODS

Intestinal lesions were caused in rats and dogs and a new biodegradable adhesive (Pebisut®) (patent granted in the European Union 07808494.4-1219, 01.12.2010, in Mexico P.C.T./MX/a/2009/001737, 16.02.2009, pending in the U.S.P.T.O. 60/762,136, 26.01.2006) was applied to compare the resistance of suture lines using bursting pressures and histologically.

RESULTS

Under acute and chronic conditions, Pebisut® strengthened and made the suture lines more resistant, while histologically penetrating and sealing them. The adhesive disappears within 2-3 weeks and is well tolerated by the intestinal tissues.

CONCLUSIONS

This biodegradable adhesive provides greater resistance, temporarily protects suture lines and may prevent anastomotic leaks.

Morbidity of laparoscopic surgery for complicated appendicitis: an international study

BACKGROUND

Although laparoscopic appendectomy has some advantages over open appendectomy, some reports do show more postoperative intraabdominal abscesses.

METHODS

A retrospective review of complicated appendicitis managed surgically by eight surgical groups from six countries was undertaken. Among 3,433 patients with appendicitis, 1,017 (29.5%) had complicated appendicitis, which included perforated or gangrenous appendicitis with or without localized or disseminated peritonitis. There were 74 preoperative abscesses (7.4%) and 5 small bowel obstructions.

RESULTS

One patient died. There were 29 postoperative intraabdominal abscesses (2.8%) and 112 mostly minor complications. Conversion to laparotomy was necessary for 28 patients (2.7%). The surgical time ranged from 32 to 132 min (mean, 62 min), and the hospital stay ranged from 1 to 18 days (mean, 3.5 days).

CONCLUSIONS

The morbidity rates, particularly for intraabdominal abscesses, were less for laparoscopic appendectomy in complicated appendicitis than those reported in the literature for open appendectomy, whereas operating times and hospital stays were similar.

Large duodenal villous adenoma requiring head of the pancreas and pylorus-preserving total duodenectomy

Villous adenomas of the duodenum (VAD) are infrequent lesions of the gastrointestinal tract but have a high risk of recurrence and malignancy. For these reasons and its specific topographic location, the surgical treatment of VAD is still controversial. Herein we present a case of large VAD located in the second duodenal portion that was successfully treated with a head of the pancreas, pylorus-preserving total duodenectomy (PPTD). PPTD should be an excellent option in patients with large adenomas because it allows preservation of the pancreas, gastrointestinal function is maintained, the possibility of a recurrence and of an invasive carcinoma of the ampulla is eliminated, and finally because it permits an adequate endoscopic follow-up. PPTD should not be used in the presence of malignancy and/or high-grade dysplasia.

Laparoscopic repair of traumatic diaphragmatic hernia

Posttraumatic diaphragmatic rupture or eventration is still a challenging problem. Herein five cases of patients with such a diaphragmatic lesion treated successfully by laparoscopy are reported with a discussion of the advantages of this mini-invasive surgical approach.

Technical modifications for laparoscopic appendetomy and other pelvic procedures using microinstruments

Reusable microinstruments are used in a modification of the three-port technique for laparoscopic appendectomy and other pelvic procedures; the method is described herein. Fifty-seven consecutive patients were operated upon using this technique. There was no mortality; there were two minor complications and no conversions to laparotomy. Pain medication needs were minimal in all patients, and the cosmetic results were excellent. The use of microinstruments for pelvic laparoscopic procedures is safe and cost-effective using the technical modifications described.

Laparoscopic diagnosis and treatment of an acute epiploic appendagitis with torsion and necrosis causing an acute abdomen

Acute epiploic appendagitis is not as rare as previously thought; but, since the presenting signs and symptoms are not specific, preoperative diagnosis has been rarely made. At the present time, a laparoscopic exploration of the peritoneal cavity will establish the correct diagnosis, and the treatment can be provided during the same procedure. Herein, a case of a 63-year-old female patient with acute abdominal syndrome caused by a necrotic epiploic appendix that was successfully diagnosed and treated laparoscopically is described. A review of the literature is made, as well.

[Critical vision in the treatment of invasive vesical cancer with ionizing radiation]

OBJECTIVE

To review the treatment of invasive bladder cancer with ionizing radiation.

METHODS

Patient selection criteria, prognostic factors, treatment of different tumor types with radiation using different strategies alone or in combination with chemotherapy are analyzed in the literature.

RESULTS/CONCLUSIONS

The role of radiotherapy in the treatment of invasive carcinoma of the bladder is crucial: 1) preoperative radiotherapy in combination with radical surgery achieves results comparable with those of cystectomy in terms of survival and a higher local control rate; 2) used in combination with cisplatin post-TUR, irradiation is highly effective for local control of the tumor and bladder preservation, with complete remission rates ranging from 60-70%, which are higher than those of radical cystectomy; 3) in this latter therapeutic modality the effect of radiotherapy is dose-related and is influenced by factors such as tumor size, presence or absence of urinary obstruction, presence of multiple lesions on the bladder wall and extravesical spread. Over the last few years, a number of therapeutic procedures have been developed, which can improve the previously mentioned results when used appropriately. Among these are hyperfractionation, accelerated irradiation and concomitant radio and chemotherapy. Studies to determine tumor radiosensitivity (Fs2/a) and the use of gene therapy could enhance the tumor control rate in the future, although a system for the selection on patients for conservative or multilating treatment based on clinical, clinicopathological and scientific criteria will have to be developed. Finally, the use of special techniques, particularly brachytherapy and intraoperative irradiation, in combination with external radiotherapy has achieved excellent results (high local control and survival rates) in certain situations, basically in single/small-sized tumours.

Laparoscopic repair of pleural laceration produced during truncal vagotomy: case report

A partial pneumothorax developed in a patient undergoing laparoscopic truncal vagotomy when a small pleural laceration was accidentally produced. Changes in oxygen saturation and PETCO2 were immediately detected by the anesthesiologist and measures were taken to maintain the patient's ventilatory stability. The pleural laceration was repaired laparoscopically, and the pneumothorax was corrected by ventilatory manipulation, avoiding the placement of a chest tube. The procedure was completed uneventfully. Literature about the causes of pneumothorax during laparoscopic procedures as well as preventive and therapy viewed.

Laparoscopic-assisted resection of a bleeding gastrointestinal stromal tumor

The authors report a case of a 29-year-old male patient with a severe lower gastrointestinal hemorrhage in whom a successful laparoscopic diagnosis and resection (assisted) of an ileal gastrointestinal stromal tumor (GIST) was performed. Laparoscopy can be very useful in the diagnosis and treatment of selected cases of lower gastrointestinal bleeding.

Stoppa-type laparoscopic repair of complex groin defects

With the laparoscopic approach, bilateral and complex groin defects can be corrected simultaneously by applying a preperitoneal mesh that covers the entire posterior wall of the groin, using a technique similar to the one described by Stoppa. We present our series of hernias repaired by the transabdominal preperitoneal laparoscopic approach with the Stoppa-type technique. The report consists of 78 cases of bilateral defects, of which 60% were indirect bilateral hernias, 23% direct bilateral, and 17% combined defects; 28.5% were recurrent hernias. Only minor complications were observed (hematomas and urinary retention) in some patients, but all resolved spontaneously. Three recurrences (0.7%) have been seen to this date. This method is recommended as the method of choice for complex groin defects.

Retrieval of specimens in laparoscopy using reclosable zipper-type plastic bags: a simple, cheap, and useful method

Surgical specimens must often be extracted during laparoscopic surgery. Although the technologic advances in this field are amazing, simple measures may sometimes work even better than very sophisticated instruments. This is true of the reclosable plastic bags with zipper-type closure that we use for retrieving surgical specimens from the abdominal cavity in order to protect it as well as the abdominal wall. The bags are cheap, offer no problems for sterilization, are easy to obtain, and are available in many sizes. They are very simple to handle, making it easy to slip in the specimen and then extract it from the abdominal cavity. We describe our experience with these bags and a technique for manipulating them.

Bowel obstruction in the postoperative period of laparoscopic inguinal hernia repair (TAPP): review of the literature

A case is presented of a male patient that presented with intestinal obstruction in the early postoperative period of a transabdominal preperitoneal inguinal repair (TAPP) that was diagnosed and repaired successfully using laparoscopy. Whenever a total extraperitoneal procedure (TEP) cannot be performed, the peritoneal closure of the TAPP should be done water-tight using interrupted stitches of absorbable monofilament sutures.

The efficacy of laparoscopic surgery in the diagnosis and treatment of peritonitis. Experience with 107 cases in Mexico City

BACKGROUND

Peritonitis continues to be an important cause of morbidity and mortality and often an etiologic diagnosis is unclear. To evaluate the efficacy and safety of laparoscopy the authors analyzed their 5-year experience with this modality of treatment.

METHODS

A review was made of 107 consecutive nonselected laparoscopic procedures performed between October 1990 and November 1995. The diagnosis was established by clinical, laboratory, and imaging findings and confirmed by laparoscopy and/or laparotomy.

RESULTS

An etiologic diagnosis was unclear in 35% of the cases and was established in all by laparoscopy; 94 patients (87.9%) were successfully treated by laparoscopy while 13 (12.1%) required conversion. Mortality was 4.6%; 14% had postoperative complications and 7.4% had reoperations.

CONCLUSIONS

Laparoscopic surgery is safe and very efficient in the diagnosis and treatment of patients with peritonitis. In most instances a definitive treatment can be carried out without conversion and has the additional and well-known advantages of minimally invasive surgery.

Use of subdiaphragmatic bupivacaine instillation to control postoperative pain after laparoscopic surgery

Although postoperative pain has been reduced significantly since the advent of laparoscopic surgery, many patients still complain of moderate abdominal and shoulder pain during the first 48 to 72 h after surgery. In this study, the effect of subdiaphragmatic instillation of bupivacaine after laparoscopic cholecystectomy was investigated. The evaluation of postoperative pain was done according to a numerical verbal scale and the dose of analgesia required. The results showed a considerable reduction of postoperative pain during the first 48 h after surgery in patients who received bupivacaine instillation. Although the literature shows certain controversy as to the effects of similar methods, our study concludes that instillation of a long-acting anesthetic, such as bupivacaine, into the subdiaphragmatic space after laparoscopic procedures is effective in postoperative pain reduction.

Cirugía Laparoscoópica para reflujo gastroesofágico

La funduplicación de Nissen es una de las operaciones pava reflujo gastroesofágico de mayor aceptación; sin embargo, es una operación con importante morbilidad para una patología benigna. Esta operación, se ha venido haciendo en los últimos años mediante cirugía laparoscópica con menores problemas que la cirugía clásica abierta. Presentamos una experiencia preliminar de 44 casos resueltos con este abordaje en el que tenemos un 94,8% de pacientes con alivio de los síntomas y mínimas complicaciones. Solo 2 pacientes requirieron una segunda cirugía. La presión final del esfinter fue de 25mmH y la longitud de la funduplicatura fue de 3.06 cms.

Laparoscopic treatment of perforated duodenal ulcer

We present a case of a perforated duodenal ulcer in an elderly malnourished, septic, diabetic patient with abnormal renal function. This patient was treated successfully with laparoscopic surgery. We suggest that similar cases can be treated by this method.

Experimental liver injury in the rhesus monkey. I. Effects of cirrhogenic diet and ethanol

Images

Cannulation of the thoracic duct and umbilical vein in patients with portal hypertension

Images

Vectorcardiographic studies in acquired valvular disease with reference to the diagnosis of left ventricular hypertrophy

A vectorcardiographic study using the Schmitt-Simonsen (SVEC-III) method was done in 92 patients with mitral and aortic acquired valvular disease in which left ventricular hypertrophy and the valvular lesions were proven by means of right and left heart catheterization, operation, or autopsy, or by all methods. Significant differences were found among groups with aortic insufficiency, aortic stenosis, and mitral insufficiency. The magnitude of the 0.01 and 0.02-sec and maximal spatial vectors and the voltages of the Q x , R x , as well as R z waves were greatest in the group with aortic insufficiency. The greatest voltages of the 0.03-sec and 0.04-sec vectors were found in patients with aortic stenosis. In this study the smaller voltages after the 0.03-sec vector were found in the group with mitral insufficiency, and these voltages were significantly increased when aortic insufficiency complicated the picture. Groups with aortic insufficiency and mitral insufficiency, or aortic stenosis or insufficiency and mitral stenosis showed abnormal inferior orientation of the middle and terminal forces, which were explained upon the basis of the concomitant right ventricular hypertrophy. The authors believe that with the aid of the corrected orthogonal system of Schmitt and Simonsen (SVEC-III) the clinician will be able not only to make a more accurate evaluation of left ventricular hypertrophy, but also in many instances will find considerable assistance in arriving at a specific clinical diagnosis.

Vectorcardiographic studies in acquired valvular disease with reference to the diagnosis of right ventricular hypertrophy

The orthogonal vectorcardiogram described by Schmitt and Simonson has been studied in 37 patients with "pure" mitral stenosis.

The diagnosis of right ventricular hypertrophy (RVH) could be established from changes in the magnitude, azimuth, and elevations of the initial, middle, and terminal forces, which could not be detected by the routine 12-lead electrocardiogram. This type of [see figure in the PDF file] recording has proved to be of great value in the diagnosis of right ventricular hypertrophy, particularly when the hypertrophy is of mild or moderate degree. Analysis of the instantaneous vectors has proved to be the single most important criterion in the electrocardiographic diagnosis of right ventricular hypertrophy.