Recyclable cyclic bio-based acrylic polymer via pairwise monomer enchainment by a trifunctional Lewis pair.

The existing catalyst/initiator systems and methodologies used for the synthesis of polymers can access only a few cyclic polymers composed entirely of a single monomer type, and the synthesis of such authentic cyclic polar vinyl polymers (acrylics) devoid of any foreign motifs remains a challenge. Here we report that a tethered B-P-B trifunctional, intramolecular frustrated Lewis pair catalyst enables the synthesis of an authentic cyclic acrylic polymer, cyclic poly(γ-methyl-α-methylene-γ-butyrolactone) (c-PMMBL), from the bio-based monomer MMBL. Detailed studies have revealed an initiation and propagation mechanism through pairwise monomer enchainment enabled by the cooperative and synergistic initiator/catalyst sites of the trifunctional catalyst.

Hands and water as vectors of diarrheal pathogens in Bagamoyo, Tanzania.

Diarrheal disease is a leading cause of under-five childhood mortality worldwide, with at least half of these deaths occurring in sub-Saharan Africa. Transmission of diarrheal pathogens occurs through several exposure routes including drinking water and hands, but the relative importance of each route is not well understood. Using molecular methods, this study examines the relative importance of different exposure routes by measuring enteric bacteria (pathogenic Escherichia coli) and viruses (rotavirus, enterovirus, adenovirus) in hand rinses, stored water, and source waters in Bagamoyo, Tanzania.

A method for radiologic-assisted gastrostomy when percutaneous endoscopic gastrostomy is contraindicated.

Background: Percutaneous endoscopic gastrostomy (PEG) has been established as a faster and safer procedure than open surgical gastrostomy. It cannot be done, however, for many patients with partially obstructing pharyngeal or esophageal carcinoma, previous gastrectomy, upper abdominal surgery, or bowel distension from distal obstruction.

Patients And Methods: We attempted percutaneous radiologic-assisted gastrostomy (RAG) in 231 patients referred for gastrostomy, 38 of whom had a relative contraindication for PEG.

Single-mode fiber coupling efficiency with graded-index rod lenses.

Losses are calculated for the single-mode graded-index- (GRIN-) lens coupler. The main advantage of this coupling system is large separation between fibers with small power loss. The excess loss of the GRIN-lens coupler is due primarily to the misalignments of the GRIN lenses and is most sensitive to angular tilt rather than lateral offset or end separation.

Effect of the mode of lipid administration on parenteral nutrition-related infections.

Objective: To determine if total nutrient admixtures (TNAs) influence the rate of infection in clinical practice.

Design: Prospective, randomized trial.

Setting: Department of Veterans Affairs Medical Center.

Uncontrollable intraabdominal hemorrhage treated with packing and use of a MAST suit. A case report.

Uncontrollable hemorrhage can occur during any surgical procedure, and only an organized approach to its control will minimize morbidity and mortality. When routine hemostatic measures fail, extraordinary methods must be used. The use of intraabdominal packs with a MAST (medical antishock trousers) suit successfully controlled a life-threatening hemorrhage in one such patient.

Systemic appearance of nutrients placed into the peritoneal cavity.

The use of the peritoneal cavity as a route for delivery of nutrients in patients on continuous ambulatory peritoneal dialysis as well as patients not in renal failure has been proposed. In earlier studies we found dogs could be maintained for 30 days through continuous peritoneal infusion of a solution of amino acids, glucose, and lipids. We then conducted experiments to observe the rate of absorption of nutrients from the gut compared to the peritoneal cavity, the relative rate absorption of amino acids, sugars, and fats, and the absorption of of glucose polymers from the peritoneal cavity.

Total nutritional support through the peritoneal cavity.

We prepared ten dogs with intraperitoneal catheters to allow total nutritional support for 30 days by constant infusion of a solution containing 1.5% amino acid, 10% glucose, and 1% lipids at a rate of 4 ml/kg/hr. Seven dogs survived in apparent good health but with a 13.

Percutaneous needle pharyngostomy.

Pharyngostomy is a technique of proven usefulness in patients requiring extra oral enteric access. Techniques to perform this have required an operating room, general anesthesia, and the associated risks. We have developed a technique for needle pharyngostomy that can be performed at the bedside of an awake patient.

Creating a continent tubeless gastrostomy.

Standard tube feeding gastrostomy is associated with a myriad of problems among which leakage of gastric contents is the most serious. Over the years many methods of creating tubeless gastrostomy have been unsuccessful because of the extent of surgery required and the persistent leakage of gastric fluids. By using gastrointestinal staplers to create a gastric tube and by incorporating a reverse intussusception valve at its base, we created a continent tubeless feeding gastrostomy in 23 patients aged 10 to 81 years.

Spontaneous resolution of intestinal obstruction while receiving home parenteral nutrition.

Six patients with intestinal obstruction secondary to benign adhesions so dense and vascular that the operating surgeon could not free them, were placed on a home total parenteral nutrition program. Four patients had enterocutaneous fistulas, and two had their bowels divided and stomas created to divert intestinal contents from distal enterotomies made during the attempt to free the intestine. The enterocutaneous fistulas closed in four patients within 2 weeks to 5 months and the obstructions spontaneously resolved in 2 to 3.

A tube for enteral nutrition of patients with aphagopraxia and patients with ventilator assistance.

A new feeding tube was designed for use in patients who cannot swallow. A comparison of our ability to pass a commercially available, mercury weighted, small feeding tube or the new, nonweighted feeding tube was made. Forty-one consecutive patients who had endotracheal intubation and who had mechanical ventilation assistance or who had suffered injuries to the central nervous system, producing aphagopraxia were compared.

Routine versus selective drainage of the gallbladder bed after cholecystectomy.

A review of 367 cases of patients undergoing cholecystectomy was made to compare the complication rates and the duration of hospital stay in the patients in whom the surgeon used routine drainage of the gallbladder bed and those in whom the surgeon used drainage selectively (only in those with severe inflammatory reaction, persistent leakage or injury to the liver bed). The patients in whom selective drainage was used had a significantly lower complication rate and a shorter hospital stay. It is concluded that routine drainage adds to the morbidity of simple cholecystectomy and should not be practiced.

Early postoperative nutritional support using the serosal tunnel jejunostomy.

A silicone rubber serosal tunnel jejunostomy for postoperative nutritional therapy was placed in 38 patients who had major operations. A dilute, chemically defined diet was begun within 48 hours of surgery and an attempt made to advance it slowly to full strength by the fifth day. No catheter-related complications occurred.

Protein-calorie malnutrition in a community hospital.

An assessment of protein-calorie status was performed on 200 consecutive adult nonobstetric admissions to a private hospital from two group family practices. Anthropometric measurements, serum albumin level, and total lymphocyte count were determined at admission and weekly if the patient remained in the hospital. Nonnutritional factors affecting muscle protein stores and serum albumin level were taken into account.

Cholecystosonography for the decision to operate when acute cholecystitis is suspected.

Forty-four patients admitted with a diagnosis of acute cholecystitis underwent immediate cholecystosonography, and if the findings were interpreted as showing gallstones, surgery was performed. The accuracy was 91 per cent. The routine use of cholecystosonography in acutely ill patients is recommended.

Management of enterocutaneous fistulas and problem stomas with silicone casting of the abdominal wall defect.

Silicone casting of abdominal wall defects around enteric fistulas in six patients and problem stomas in three patients proved to be an effective means of controlling the output of the fistulas, reducing wound care time, and reducing or eliminating parenteral nutrition needs. Outpatient management was possible in seven of the nine patients. It is observed that the wounds healed rapidly with this method of fistula control.

The management of infected abdominal aortic grafts and graft-enteric fistulas.

Seven cases of infected aortic grafts or aorto-enteric fistulas following resection of an abdominal aortic aneurysm are reviewed. All cases were treated with axillo-femoral bypass and graft removal. Patients had recurrent fever, chills, and abdominal pain (5 patients), or massive gastrointestinal hemorrhage (2 patients).

Repair of massive septic abdominal wall defects with Marlex mesh.

Marlex mesh was used to close the abdominal wall defect in six patients with septic wound dehiscence and intra-abdominal infection. The mesh was implanted under local anesthesia and served as a protective covering for the bowel and allowed early ambulation, including prone positioning of the patient for easier wound care. In four surviving patients, the Marlex mesh was covered by full thickness skin flaps after granulation tissue had covered the material.

Diagnostic peritoneal lavage in evaluating acute abdominal pain.

A study was performed to determine the value of peritoneal lavage in the acute abdomen not related to trauma. Lavage was performed in 33 patients in the evaluation of abdominal pain of sufficient degree to warrant consideration for surgical intervention. Peritoneal lavage was truly positive or truly negative in 64% of the cases.

Results of routine preoperative sigmoidoscopy and barium enema on patients with inguinal hernia.

The diagnostic findings of history, physical examination, rectal examination, barium enema, and sigmoidoscopy in 684 patients with the initial complaint of inguinal hernia were examined. History and physical examination led to the diagnosis of four cancers of the colon and one villous adenoma. No significant new findings were made by sigmoidoscopy when symptoms elicited by history did not indicate some abnormality.