Reversible Diels-Alder and Michael Addition Reactions Enable the Facile Postsynthetic Modification of Metal-Organic Frameworks.

Functionalization of metal-organic frameworks (MOFs) is critical in exploring their structural and chemical diversity for numerous potential applications. Herein, we report multiple approaches for the tandem postsynthetic modification (PSM) of various MOFs derived from Zr(IV), Al(III), and Zn(II). Our current work is based on our efforts to develop a wide range of MOF platforms with a dynamic functional nature that can be chemically switched via thermally triggered reversible Diels-Alder (DA) and hetero-Diels-Alder (HDA) ligations. Furan-tagged MOFs (furan-UiO-66-Zr) were conjugated with maleimide groups bearing dienophiles to prepare MOFs with a chemically switchable nature. As HDA pairs, phosphoryl dithioester-based moieties and cyclopentadiene (Cp)-grafted MOF (Cp-MIL-53-Al) were utilized to demonstrate the cleavage and rebonding of the linkages as a function of temperature. In addition to these strategies, the Michael addition reaction was also applied for the tandem PSM of IRMOF-3-Zn. Maleimide groups were postsynthetically introduced in the MOF lattice, which were further ligated with cysteine-based biomolecules via the thiol-maleimide Michael addition reaction. On the basis of the versatility of the herein presented chemistry, we expect that these approaches will help in designing a variety of sophisticated functional MOF materials addressing diverse applications.

Orbital mass secondary to acute lymphoblastic leukaemia in a child: a rare presentation.

We report the case of a 3-year-old child, who presented with lid swelling which progressed to proptosis of the left eye. He also had systemic symptoms of fatigue and weight loss. An examination revealed hepatosplenomegaly and lymph node enlargement. Investigations showed a peripheral smear with blast cells, which were also revealed through a bone marrow biopsy. A CT scan showed a mass lesion in the left orbit that had infiltrated into the surrounding tissues. He was diagnosed with acute lymphoblastic leukaemia (ALL) with left-sided orbital mass secondary to it. Haematogenous masses in the orbit are commonly due to granulocytic sarcomas, which are usually associated with acute myelogenous leukaemia (AML), not ALL, and are rare especially when they precede systemic disease.

A phase II randomized placebo-controlled trial of omega-3 fatty acids for the treatment of acute lung injury.

OBJECTIVES: Administration of eicosapentaenoic acid and docosahexanoic acid, omega-3 fatty acids in fish oil, has been associated with improved patient outcomes in acute lung injury when studied in a commercial enteral formula. However, fish oil has not been tested independently in acute lung injury. We therefore sought to determine whether enteral fish oil alone would reduce pulmonary and systemic inflammation in patients with acute lung injury. DESIGN: Phase II randomized controlled trial. SETTING: Five North American medical centers. PATIENTS: Mechanically ventilated patients with acute lung injury ≥18 yrs of age. INTERVENTIONS: Subjects were randomized to receive enteral fish oil (9.75 g eicosapentaenoic acid and 6.75 g docosahexanoic acid daily) or saline placebo for up to 14 days. MEASUREMENTS AND MAIN RESULTS: Bronchoalveolar lavage fluid and blood were collected at baseline (day 0), day 4 ± 1, and day 8 ± 1. The primary end point was bronchoalveolar lavage fluid interleukin-8 levels. Forty-one participants received fish oil and 49 received placebo. Enteral fish oil administration was associated with increased serum eicosapentaenoic acid concentration (p < .0001). However, there was no significant difference in the change in bronchoalveolar lavage fluid interleukin-8 from baseline to day 4 (p = .37) or day 8 (p = .55) between treatment arms. There were no appreciable improvements in other bronchoalveolar lavage fluid or plasma biomarkers in the fish oil group compared with the control group. Similarly, organ failure score, ventilator-free days, intensive care unit-free days, and 60-day mortality did not differ between the groups. CONCLUSIONS: Fish oil did not reduce biomarkers of pulmonary or systemic inflammation in patients with acute lung injury, and the results do not support the conduct of a larger clinical trial in this population with this agent. This experimental approach is feasible for proof-of-concept studies evaluating new treatments for acute lung injury.

The ArtAssist Device in chronic lower limb ischemia. A pilot study.

BACKGROUND: Patients with chronic critical limb ischemia following a failed bypass graft or with non-reconstructable distal disease diagnosed angiographically, have a very poor prognosis. This is a prospective pilot study to assess the influence of the ArtAssist Device on pedal blood flow and amputation rate. METHODS: Thirty-three legs in 25 patients were evaluated. Ten legs presented with rest pain, and 23 legs with tissue loss. Nine legs had previously undergone bypass surgery. RESULTS: At a mean follow-up of 3 months, 14 (42%) legs were amputated, and 19 (58%) were saved. Eleven of the amputated legs were in patients with chronic renal failure, a known risk factor. The amputation rate, excluding this group, was 13.6% (3/22). Toe pressures measured initially and after 3 months on the pump showed a significant improvement (p=0.03). Forty percent of patients presenting with rest pain improved, while 26% of foot ulcers healed on the pump. Mortality rate was 12%. CONCLUSIONS: The results from this prospective study are encouraging but need to be validated in a larger prospective randomized study.

Gunshot injuries of the extrahepatic biliary ducts.

OBJECTIVE: To assess our management of gunshot injuries of the extrahepatic biliary ducts. DESIGN: Retrospective study. SETTING: Urban teaching hospital, South Africa. SUBJECTS: 17 patients who were found to have gunshot injuries of the extrahepatic bile ducts, January 1993-June 1998. INTERVENTIONS: Packing and damage control, staged repair, or definitive repair. MAIN OUTCOME MEASURES: Morbidity and mortality: Three of the 17 died intraoperatively or postoperatively from causes unrelated to the biliary injury. Of the 14 survivors, 3 were managed initially with packing and damage control, 7 by staged repair, and 4 by definitive biliary repair. Eleven patients had a Roux-en-Y biliary jejunostomy, of whom 1 developed a late biliary stricture related to a postoperative anastomotic leak. End-to-end anastomosis of the bile duct was done for 2 patients and they both developed late biliary strictures. Ligation of the injured duct and cholecystojejunostomy was done for I patient. CONCLUSION: Roux-en-Y biliary-jejunal anastomosis is appropriate in the treatment of gunshot injuries of the extrahepatic biliary ducts as there is always a degree of tissue loss and some debridement is required, making it difficult to do a tension-free anastomosis.

Débridement of gunshot wounds: semantics and surgery.

Débridement is a well established modality for management of gunshot wounds. The word "débridement" is originally French. It was used for the first time during the eighteenth century in the surgical context and meant "wound incision." For French surgeons, it has retained to this day its original meaning. In medical English, though, the use of the term has been marred by persisting confusion about its definition. Two quite different surgical procedures still compete for the definition of débridement: wound incision and wound excision. These procedures are also at the center of a modern controversy about the management of gunshot wounds. The orthodox doctrine, inherited from military surgeons, consists of aggressive tissue excision around the bullet track. This radical policy is being challenged by advocates of a more conservative approach. Minimal tissue excision is sufficient and safe in many cases provided careful monitoring of the wound is instituted. Wound incision alone to relieve tension and allow drainage is possible in certain cases. The tug-of-war between excision and incision is outlined herein with reference to the semantic tribulations of the word "débridement" and the implications for patient care.

Transmediastinal gunshot injuries.

BACKGROUND: Transmediastinal gunshot injuries are a rarely reported injury. Until recently, assessment of the thoracic aorta by angiography preceded the investigation of the esophagus. This order has been recently debated. METHODS: There were 118 patients with potential transmediastinal injuries included in this retrospective study. Unstable patients who were unresponsive to resuscitation were taken to the operating room without previous investigation. Stable patients were routinely investigated initially for injury of the aorta and then for injury of the esophagus. RESULTS: There were 51 patients who underwent urgent thoracotomy/sternotomy. In 27, the hemorrhage was of mediastinal origin; 17 of these patients died of intraoperative bleeding. Eight of the patients had aortic injury, and only one of this group survived. There were 57 stable patients who were investigated initially for injury of the aorta by angiography. It was positive in only one patient who underwent an operation with good results. An investigation of the esophagus followed and revealed esophageal injury in 17 patients. All of them were treated operatively, 15 of them with satisfactory outcome. CONCLUSIONS: Angiography should at present precede esophageal investigations. There is a need for shortening the time between admission and operation. Other modalities that could expedite the investigation of the thoracic aorta and the esophagus should be prospectively evaluated in multi-center studies.

Non-operative treatment of abdominal gunshot injuries.

BACKGROUND: Non-operative treatment is a management option that challenges the traditional mandatory laparotomy for abdominal gunshot injuries. METHODS: All published relevant clinical reports were retrieved by searching through the Medline database and manually. The theoretical arguments in favour of non-operative management as well as the results of the reviewed reports are analysed and evaluated. RESULTS AND CONCLUSION: Patients with proven non-penetration of the abdominal cavity can be offered conservative treatment with a satisfactory outcome. Greater caution should be exercised in the presence of a documented visceral injury until the safety of this option has been established by further clinical trials.

Controversies in management of penetrating injuries of the pancreas.

The management of penetrating pancreatic injuries is still beset by controversy, especially with regard to the role of pancreatography, the most appropriate operation, the type of drainage and the adjunctive role of ocreotide. The recommendations of various experts are outlined and evaluated in the light of the authors' personal experience. Consensus is easily achieved for very minor and very severe injuries. Most management discussions center around those injuries resulting in parenchymal disruption of a degree of severity sufficient to raise doubts about the integrity of the main pancreatic duct.

Organisation of hospital responses for the trauma epidemic.

The caseload of the Department of Surgery (Baragwanath Hospital, Johannesburg, South Africa) is characterised by a singularly heavy trauma component. Penetrating injuries account for the majority of cases. The management of penetrating trauma is not as demanding as that of blunt trauma, yet the sheer number of cases, over the past four decades, has imposed a clinical burden that has never been met by commensurate resources. The organisation of the hospital and departmental responses has manifested itself on two different levels. The first one is the structural and functional deployment of insufficient staff, facilities and equipment to cope as flexibly as possible with the trauma epidemic. The second one is the gradual adaptation of the clinical management philosophy to ensure that the best possible quality of care is provided to the majority of trauma victims, with the full knowledge that better resources would sometimes have elicited a different clinical approach.

Laparoscopic inguinal hernia repair by an intraperitoneal onlay mesh technique using expanded PTFE: a prospective study.

This prospective trial was initiated to assess laparoscopic inguinal hernia repairs by an intraabdominal intraperitoneal onlay mesh (IPOM) technique. An IPOM method utilizing 10 x 7.5-cm expanded polytef (PTFE) patches was used to repair 52 inguinal hernias in 50 patients. There were two patients with bilateral defects. Fourteen were direct and 38 were indirect hernias. There was one patient with bladder perforation, one with strangulation of the small bowel that entered the sac of a recurrent defect, and five patients with other minor complications. There were two recurrences. The follow-up period ranged from 7 to 31 months. The operating time ranged from 35 to 180 min and was 35-60 min in 40 patients. The postoperative pain was minimal in 40 patients. Our conclusions are as follows: This IPOM method was less time consuming in theater time than other laparoscopic methods. There was minimal postoperative pain in the majority of cases. The hospital stay was shorter in comparison with the standardized stay for conventional methods. The case with recurrence and strangulation raises some questions as to the safety of this method. Hospital costs of conventional herniorrhaphies were lower (63%) than those of this laparoscopic method.

Selective surgical management of zone II gunshot injuries of the neck: a prospective study.

BACKGROUND: The management of penetrating neck trauma remains controversial, with many studies supporting either mandatory exploration or selective conservatism. METHODS AND RESULTS: This is a prospective study of 75 patients with gunshot injuries to zone II of the neck. Forty patients (53.3%) underwent immediate exploration because of clinical indications or positive initial investigations. A 7.5% incidence of unnecessary explorations, a 5% mortality rate, and average hospital stay of 10.5 days were noted. Thirty-five patients with negative clinical or investigational findings underwent observation with constant monitoring. A 5.7% incidence of missed injuries, no mortality, and an average hospital stay of 3.5 days were noted for these patients. CONCLUSIONS: We suggest that conservative management in gunshot injuries confined to zone II of the neck selectively supplemented by appropriate investigations is a viable proposition in this type of injury. Further contemporary studies reporting specifically on this injury will enable us to reach statistically significant conclusions.

Perforation of the gastro-intestinal tract by a foreign body. A case report.

Most ingested foreign bodies pass through the gastro-intestinal tract without giving rise to complications. If they become lodged in a narrow segment of the gastro-intestinal tract, perforation may occur. The resulting morbidity depends on the further route of the penetrating object and whether septic sequelae ensue. This article describes an unusual case of foreign body perforation with a protracted clinical course. It emphasises that there are no insurmountable barriers in the pathway of foreign bodies.

Penetrating injuries of the iliac arteries: a South African experience.

BACKGROUND: We did a retrospective study of 62 patients with penetrating injuries of the iliac arteries. METHODS: The cause of injury was gunshot wound in 85.5% and stabbing in 14.5%. The arterial repair was achieved by various means: lateral arteriorrhaphy, end-to-end anastomosis, and polytetrafluoroethylene interposition grafts. RESULTS: There was a 42% mortality rate from exsanguination or secondary coagulopathy directly related to the arterial injury. Persistent shock, resuscitative thoracotomy, free intraperitoneal hemorrhage, and the number of vascular injuries were directly related to mortality. CONCLUSIONS: A high index of suspicion, aggressive resuscitation, and prompt surgery are necessary to improve the chances of surviving this ominous injury.

Volvulus of the sigmoid colon at Baragwanath Hospital.

Fifty-six patients treated for sigmoid volvulus over a period of 5 years are reviewed. The purpose of this study is to evaluate our management policy and to compare it with other studies, particularly from other parts of Africa. The patients were evaluated by retrospective allocation into one of three treatment modalities. Patients with clinical evidence of ischaemia underwent a Hartmann's procedure. There was a 33% mortality rate in this group. In those patients who had sigmoidoscopic reduction, a second-stage sigmoidectomy and primary anastomosis were performed. The results in this group were excellent. In the group of patients with failed sigmoidoscopic resection the majority underwent a Hartmann's procedure with a mortality rate of 15%.

Chondroid syringoma of the abdominal wall. A case report and review of the literature.

A case of an unusually large chondroid syringoma of the abdominal wall is described. Chondroid syringomas are rare neoplasms believed to be of sweat gland origin. They are often slow-growing and benign. Local recurrence and distal spread characterise the malignant form.

Gunshot injuries of the head of the pancreas: conservative approach.

This study is comprised of 48 patients with gunshot injuries of the head of the pancreas, many of which were high velocity injuries. The purpose of this study was to evaluate our management policy for these injuries based on our recent wide experience. Patients with grade II and III injuries underwent conservative surgery, with 0% and 21% postoperative mortality, respectively, directly related to the pancreatic injury. For patients in whom the duodenum was involved, pyloric exclusion was applied depending on the grade of the duodenal injury. We concluded that moderate gunshot injuries of the head of the pancreas (grade II) can be safely treated by débridement and suture repair, with or without drainage. Severe (grade IV) injuries warrant a pancreaticoduodenectomy. Most grade III injuries can be treated by débridement and drainage unless an associated severe duodenal injury is present, in which case resection may be indicated.