Pretargeting strategies for radio-immunoguided tumour localisation and therapy.

The selective recognition of tumour cells by monoclonal antibodies, labelled with radioactive isotopes, for use in diagnosis and treatment, forms the basis of immunoscintigraphy, radio-immunoguided surgery and radio-immunotherapy. Research into the application of these systems has encountered multiple difficulties, most notably a low tumour to non-tumour ratio of radioactivity. The development of pretargeting systems, separating the individual steps of tumour cell targeting and the introduction of the radioactive label, have led to significant increments in tumour to non-tumour ratios and an improvement in diagnostic accuracy. Before pretargeting strategies are applied clinically, a thorough understanding of these systems is required and forms the backbone of this report. Clinical examples of early trials have already confirmed many of the theoretical advantages of pretargeting systems and new protocols are already being investigated.

Sentinel node localisation: A new prospective in the treatment of nodal melanoma metastases.

Sentinel node (SN) mapping and biopsy is a procedure that accurately stages the regional lymph node (LN) basin. Defined patterns of lymphatic drainage allow intraoperative determination of the first (sentinel) lymph node in the regional basin, and the absence of metastatic disease in the SN accurately reflects the absence of melanoma in the remaining regional nodes. The use of radiocolloid and a hand-held gamma detecting probe (GDP) together with a vital blue dye provides optimal results, and allows for the successful identification of the SN in over 99% of the procedures. Close collaboration between surgeons, nuclear radiologists and pathologists is required to ensure optimal results. Examination of serially sectioned SNs by hematoxylin-eosin staining (H&E), immunohistochemical staining and perhaps in the near future RT-PCR should reduce the number of patients with missed microscopic melanoma in the regional lymph nodes. Furthermore, the survival benefit recently reported in patients with melanoma metastatic to regional nodes using high dose of interferon alpha-2b signals that the surgeons should aggressively examine patients for the presence of occult regional melanoma metastases. Intraoperative SN mapping and SN biopsy are cost-effective procedures that allows accurate identification of regional lymph nodes that contain metastatic melanoma.

Sentinel node localization in primary melanoma: preoperative dynamic lymphoscintigraphy, intraoperative gamma probe, and vital dye guidance.

BACKGROUND: Sentinel node (SN) biopsy can be used to select patients with primary melanoma for therapeutic lymphadenectomy. The aim of the study was to assess the efficacy of 3 methods to locate the SN: preoperative dynamic lymphoscintigraphy, intraoperative patent blue dye (PBD), and gamma-detecting probe (GDP). METHODS: We studied 133 patients with cutaneous melanoma and clinically negative lymph nodes. Within 24 hours before surgery, colloid labeled with technetium 99m was injected intradermally around the site of the primary melanoma. The patients were studied before their operations by using dynamic lymphoscintigraphy. A total of 208 SNs were found in 164 lymph node basins. In addition, all the patients had PBD injected immediately before the surgical procedure. When the blue-stained node was identified intraoperatively, its radioactivity level was measured with the GDP. In the absence of blue coloration, the GDP was used to trace the SN. RESULTS: Of 208 SNs, 168 (80.8%) were identified in the regional draining basin during intraoperative lymphatic mapping by using PBD. By using the GDP method, 202 (97.1%) of 208 were identified (GDP vs PBD; P < .01). By combining the 2 methods, 206 (99%) of 208 SNs were detected. Of the 133 patients, 29 (21.8%) had pathologically positive SNs, and were subsequently subjected to regional lymphadenectomy. In 26 (89.7%) of 29 patients, the SN was the only node with metastasis. Three cases (10.3%) of recurrence in patients with microscopic SN metastasis and 7 cases (6.7%) of recurrence in patients without SN metastasis were found during a median follow-up of 566 days. CONCLUSIONS: Preoperative dynamic lymphoscintigraphy and intraoperative mapping with PBD and GDP offer simple and reliable methods of staging regional lymph nodes without subjecting every patient to a regional lymphadenectomy.

Five risk factors identify patients with gastroesophageal intussusception.

HYPOTHESIS: Risk factors in patients with gastroesophageal intussusception who have noncardiac chest pain need to be identified and analyzed. DESIGN: Prospective consecutive series of 43 patients with gastroesophageal intussusception. SETTING: Outpatient gastrointestinal endoscopy suite for 42 patients; 1 patient sustained gastroesophageal intussusception during labor and delivery and underwent an emergency laparotomy. INTERVENTION: Upper gastrointestinal tract endoscopy under intravenous sedation with appropriate monitoring of vital signs and photographic documentation in most patients. RESULTS: Gastroesophageal intussusception was documented endoscopically in 42 of 43 patients and was found to occur equally in men and women. Five risk factors have been identified: eating disorders or alcohol abuse, sudden sustained exertion, small-bowel obstruction, acid bile peptic disease, and pregnancy. Fifteen (70%) of 22 men were younger than 35 years; precipitating factors included sustained athletic effort and binge eating and drinking episodes. Fifteen (70%) of the 21 women were older than 35 years and had binge eating, peptic disease, and complications of pregnancy as risk factors. CONCLUSIONS: Five risk factors identify patients with severe vomiting or retching who are most likely to develop gastroesophageal intussusception, the precursor of a Mallory-Weiss tear. Upper gastrointestinal tract endoscopy with photographic documentation is the most accurate method of diagnosis. For most patients, medical management can reverse the cause of the vomiting. If vomiting is caused by mechanical obstruction or massive hemorrhage, surgical intervention may be necessary.

Radioimmunoguided surgery and colorectal cancer.

Radioimmunoguided surgery is a technique that aims to delineate the extent of epithelial neoplasms (primary/recurrent) and their spread (local, regional, and distant) which are not adequately visualized by conventional imaging techniques. The target lesion binds radiolabelled, tumour-associated monoclonal antibodies which are administered in the days before surgery and which bind to the target lesion. The radiotracer is detected intraoperatively using a hand-held gamma detecting probe. This identifies the extent of the tumour, involvement of lymph nodes or other organs and may allow a more complete surgical clearance of the tumour. This article provides a basic understanding of the RIGS (radioimmunoguided surgery) technique, the monoclonal antibodies which are used and outlines the advantages and limitations of this technique.

Hemodialysis access operations performed upon patients with human immunodeficiency virus.

Hemodialysis in known patients infected with human immunodeficiency virus (HIV) has been a subject of controversy. During a 60 month period, 28 hemodialysis access operations were performed upon 22 HIV infected patients. The indication for all procedures was need of dialysis access secondary to end-stage renal failure (ESRF). Operations included 24 arteriovenous dialysis grafts and four Cimino arteriovenous fistulas. All patients had a diagnosis of acquired immunodeficiency syndrome (AIDS) (five), AIDS related complex (six) or were HIV-positive (11) at the time of the operations. All of these patients were intravenous drug abusers. Follow-up study ranged from nine days to 13 months. During the course of this study, two patients died of the progression of AIDS for a mortality rate of 9 per cent. There were nine perioperative complications for a rate of 32 per cent. These results led us to conclude that hemodialysis access operations have application in HIV infected patients with ESRF, and hemodialysis should be considered an appropriate modality in those patients requiring long term dialysis.

Small bowel obstruction following endoscopic extraperitoneal-preperitoneal herniorrhaphy.

Laparoscopic hernia repair has a number of unique potential complications. These include complications of pneumoperitoneum, general anesthesia, trocar injuries and complications of small bowel obstruction related to trocar site fascial defects, intraabdominal adhesions, and reaction with the synthetic mesh. A totally extraperitoneal approach should, in theory, eliminate postoperative small bowel obstruction in that the peritoneal space is never entered. A case of small bowel obstruction following totally extraperitoneal-preperitoneal herniorrhaphy is presented.