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Biomedical subjects

K C Conlon

Publications and source records attributed to K C Conlon.

67 records · Page 4Linked to original sources
PubMed1990

Exacerbation of symptoms of autoimmune disease in patients receiving alpha-interferon therapy.

The occurrence of autoimmune disease in patients receiving alpha-interferon (alpha-IFN) therapy has been reported in several studies; these include autoimmune thyroiditis, thrombocytopenia, anemia, exacerbation of psoriasis, and the occurrence of sarcoidosis. The primary mechanism presumably is the emergence of autoantibodies to various structural proteins or receptors. Two studies have recently shown that a significant percentage of patients treated with recombinant alpha-interferon (r alpha-IFN) do form autoantibodies. The authors report six additional cases of development or exacerbation of autoimmune phenomena in patients receiving alpha-IFN therapy. Five of these patients developed symmetric polyarthropathies and the sixth had thyroiditis. The presence of a history of underlying autoimmune disease or baseline serologic abnormalities in five of these patients, including the patient who developed thyroiditis, suggests that alpha-IFN treatment can lead to the exacerbation of an underlying subclinical autoimmune process.

Adult↗
PubMed1989

Validation of transport measurements in skeletal muscle with N-13 amino acids using a rabbit isolated hindlimb model.

We are studying the transport of C-11 and N-13 labeled amino acids in tumor-bearing rabbits to determine the role of amino acid transport in the pathogenesis of muscle wasting in cancer. To validate a new, in vivo, method for measuring transport in skeletal muscle with these compounds, an isolated hindlimb model was developed in rabbits. The limb was perfused with a non-recirculating, normothermic, constant pressure system and a cell-free perfusate. Hemodynamic and metabolic parameters were measured during the first 75 min. of perfusion and found to remain normal and stable. Flow varied directly with perfusion pressure over the normal range of resting flows in the intact rabbit hindlimb. Time-activity curves (TAC's) were recorded from the medial thigh following bolus co-injection of L-[amide N-13] glutamine or N-13 L-glutamate with Tc-99m human serum albumin (HSA) into the femoral artery. Regional plasma flow was determined from the Tc-99m data. The N-13 TAC's consistently manifested a three-phased washout with half times of approximately 30 sec., 5 min. and 2 hr. Capillary and cellular transport parameters were computed from the N-13 data using a double barrier, single capillary model of capillary and cellular transport and assuming that the three washout components result, respectively, from tracer throughput, extraction into the interstitial space and extraction into the intracellular space. This interpretation was validated and the sensitivity of the technique to transport processes demonstrated by examining the effects on the N-13 TAC's and computed transport parameters of several factors known to influence cellular transport of amino acids, viz., the insulin concentration, amino acid concentration and pH of the perfusate. Time-activity curves and transport parameters for N-13 L-glutamine in the isolated limb were very similar to those observed in the intact rabbit hindlimb, suggesting that studies in the perfused model are indicative of amino acid transport in vivo. The methodology described here is especially well suited for studying the specific effects on transport of factors which influence amino acid metabolism in skeletal muscle (e.g., hormones and monokines).

Amino Acids↗
PubMedDate not supplied

Laparoscopic evaluation in pancreatic cancer.

Pancreatic cancer continues to carry a poor overall prognosis. The majority of patients have advanced disease at the time of presentation. Dynamic, contrast-enhanced computed tomography (CT) has become the radiographic study of choice in the pre-operative staging of patients with pancreatic cancer. While it has been shown to be highly sensitive in determining unresectability of peri-ampullary tumors, the ability of CT to predict accurately which tumors can be safely resected is still limited. Laparoscopic staging of peri-ampullary tumors is superior to dynamic CT in visualizing small liver and peritoneal metastases. The addition of laparoscopic ultrasound during laparoscopic staging enhances the ability of laparoscopy to determine resectability of these tumors and approaches the accuracy of open exploration without increasing significant morbidity or mortality. Patients who are deemed unresectable at the time of laparoscopy can undergo palliative biliary and/or gastric bypass procedures laparoscopically and further minimize the morbidity of laparotomy.

Algorithms↗
PubMedDate not supplied

Peritoneal lavage cytology in gastric cancer: an independent predictor of outcome.

BACKGROUND: The prevalence and significance of free cancer cells in the peritoneal cavity of clinically M0 gastric cancer patients is unknown. We reviewed our results with peritoneal washings to determine (1) the prevalence of positive cytology in M0 and M1 disease and (2) the influence of positive cytology on the pattern of failure and survival. METHODS: Laparoscopic washings were obtained from 127 patients with gastric cancer at Memorial Sloan-Kettering Cancer Center from December 1, 1990 to August 1, 1996. Cytology was performed by the Papanicolau technique. RESULTS: The prevalence of positive cytology was as follows: 0% (0/45) in T1/T2 M0 disease; 10% (3/31) in T3/T4 M0 disease; and 59% in M1 disease. The three M0 patients with positive cytology recurred intra-abdominally (median follow up of 8.5 months). Survival was significantly less compared with stage-matched controls with negative cytology resected for cure (P <.03), and the same as those patients with stage IV disease. CONCLUSION: Patients with positive lavage cytology are stage IV, even in the absence of macroscopic peritoneal disease. Laparoscopic lavage cytology is a rapid technique for identifying the subset of M0 patients who are unlikely to benefit from resection alone. Such patients require additional treatment strategies to improve survival.

Adenocarcinoma↗
PubMedDate not supplied

Splenic preserving distal pancreatectomy of a solid pseudopapillary pancreatic tumour.

BACKGROUND: Solid pseudopapillary tumours are rare primary lesions of the pancreas. They occur most commonly in young female patients. They are traditionally regarded as benign tumours with malignant potential. AIM: We describe the incidental finding of this rare pancreatic lesion in a healthy 37-year-old female which was treated with splenic preserving distal pancreatectomy. RESULTS: The patient underwent curative resection with an uncomplicated postoperative course. Histology revealed the tumour origin with clear resection margins. The patient did not require adjunct therapy. Follow-up computed tomography (CT) scanning has demonstrated no evidence of local recurrence. CONCLUSION: The authors conclude that splenic preservation is safe and desirable where no compromise in oncological principles exists. Despite improvements in histological characteristics of solid pseudopapillary tumours, no prognostic features exist and each case must be followed-up on an individual basis.

Adult↗
PubMedDate not supplied

An unusual case of appendicitis.

BACKGROUND: Acute appendicitis in elderly patients often presents late and atypically. Presentation as an incarcerated femoral hernia is rare. AIM: To describe the management of an elderly patient presenting with acute appendicitis in an incarcerated femoral hernia. METHODS: The femoral canal was explored and the hernia repaired. Formal appendicectomy was performed via a midline laparotomy incision. RESULTS: Histological examination confirmed the diagnosis of acute appendicitis. CONCLUSION: Unusual clinical presentations of acute appendicitis represent an interesting diagnostic challenge.

Acute Disease↗
PubMedDate not supplied

Role of laparoscopy in the initial multimodality management of patients with near-obstructing rectal cancer.

The purpose of this study was to investigate the role of diagnostic laparoscopy in the multimodality management of locally advanced, near-obstructing rectal cancer. Fourteen patients with near-obstructing adenocarcinoma of the rectum (8 men and 6 women; mean age 49 years) underwent staging laparoscopy and formation of a sigmoid loop colostomy (n = 7), transverse colostomy (n = 4), or ileostomy (n = 3). The mean operative time was 78 minutes (range 67 to 94 minutes). All patients began a regular diet on postoperative day 1 and the median time to discharge was 4 days (range 2 to 8 days). Four patients were found to have diffuse peritoneal carcinomatosis not defined on preoperative CT scan. These patients died of disease within 6 months. Ten patients with advanced, localized pelvic disease began preoperative combined-modality treatment (5040 cGy external-beam radiation therapy in conjunction with 5-fluorouracil/leucovorin) between 8 and 13 days (median 9 days) following laparoscopy, and all underwent successful resection with clear margins in a median time of 12 weeks following laparoscopy. In the initial management of patients with near-obstructing advanced rectal cancer, laparoscopy can be both therapeutic and diagnostic by clarifying the site of the primary tumor, identifying patients with unsuspected peritoneal disease, and facilitating the formation of a defunctioning stoma with minimal morbidity. This leads to the early commencement of preoperative combined-modality treatment and does not compromise the prospects of subsequent tumor resection.

Adenocarcinoma↗
PubMedDate not supplied

Preoperative biliary drainage: impact on intraoperative bile cultures and infectious morbidity and mortality after pancreaticoduodenectomy.

Whether it is necessary to perform biliary drainage for obstructive jaundice before performing pancreaticoduodenectomy remains controversial. Our aim was to determine the impact of preoperative biliary drainage on intraoperative bile cultures and postoperative infectious morbidity and mortality following pancreaticoduodenectomy. We retrospectively analyzed 161 consecutive patients undergoing pancreaticoduodenectomy in whom intraoperative bile cultures were performed. Microorganisms were isolated from 58% of these intraoperative bile cultures, with 70% of them being polymicrobial. Postoperative morbidity was 47% and mortality was 5%. Postoperative infectious complications occurred in 29%, most commonly wound infection (14%) and intra-abdominal abscess (12%). Eighty-nine percent of patients with intra-abdominal abscess (P = 0.003) and 87% with wound infection (P = 0.003) had positive intraoperative bile cultures. Microorganisms in the bile were predictive of microorganisms in intraabdominal abscess (100%) and wound infection (69%). Multivariate analysis of preoperative and intraoperative variables demonstrated that preoperative biliary drainage was associated with positive intraoperative bile cultures (P <0.001), postoperative infectious complications (P = 0.022), intra-abdominal abscess (P = 0.061), wound infection (P = 0.045), and death (P = 0. 021). Preoperative biliary drainage increases the risk of positive intraoperative bile cultures, postoperative infectious morbidity, and death. Positive intraoperative bile cultures are associated with postoperative infectious complications and have similar microorganism profiles. These data suggest that preoperative biliary drainage should be avoided in candidates for pancreaticoduodenectomy.

Abdominal Abscess↗
PubMedDate not supplied

Fiberglass limb phantoms: fabrication and use for quantitative scintigraphy.

Quantitative radionuclide scintigraphy often requires empirical calibration factors derived from phantoms which simulate the radioactivity distribution, tissue geometry and tissue composition of the region of interest. This paper describes a method in which casts made with fiberglass tape of the region of interest. This paper describes a method in which casts made with fiberglass tape are used to form realistic, water-fillable phantoms of the limbs. Phantoms were constructed for the hind legs of the dog and rabbit, species frequently used in developing new radioscintigraphic techniques. Leg bones removed from euthanized animals were mounted anatomically within the casts. The dimensions of the phantom cavities were determined by x-ray computed tomography. A procedure was developed for orienting the phantoms to match the hind leg geometry of a given experimental setup. Use of the phantoms for image activity calibration is illustrated for a geometric-mean counting technique used to determine 99mTc activity densities in soft-tissue regions of the dog thigh. Generalization of the calibration technique to planar and tomographic imaging is straightforward. In situ measurements of 99mTc activity density obtained by external counting were compared with in vitro radioassays of excised tissue. For 22 tissue samples obtained from four dogs, the in situ and in vitro data were linearly correlated (r = 0.98, p much less than or equal to 0.001) over a 50-fold range of activity density. The mean and standard deviation of the observed percent discrepancies [% discrepancy = 100 (in situ - in vitro)/in vitro] were (7.8 +/- 2.9) and (13.7 +/- 2.1), respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMedDate not supplied

Staging laparoscopy for gastric cancer.

The growing role of multimodal treatment plans for advanced gastric cancer has contributed to the development of more accurate preoperative staging strategies. The high diagnostic efficacy of video-laparoscopy as regards the M factor has been reported by many; preoperative laparoscopy therefore permits to avoid unhelpful surgical exploration in case of peritoneal dissemination of tumor or liver metastases undetected by conventional staging. At Memorial Sloan Kattering Cancer Center preoperative staging laparoscopy is currently included in the diagnostic algorithm for gastric cancer. Data from a consecutive series of 103 patients demonstrated metastatic disease in 24 patients (37%) who were considered to have localized cancer by computed tomography (CT) or endoscopic ultrasonography (EUS), with an accuracy of 94% with respect to the M factor. These patients did not require open surgery. Laparoscopic washings were obtained from 127 patients with gastric cancer and a positive correlation between the extent of disease and prevalence of positive cytology was noted (T1/T2: 0%, T3/T4: 10%, M+: 59%). Our experience suggests that laparoscopy has added value in staging patients with gastric carcinoma. It appears to be a safe and effective staging modality, avoiding unnecessary explorations and providing new means of directing appropriate treatment strategy.

Algorithms↗
PubMedDate not supplied

Advances in the surgical management of pancreatic cancer.

Pancreatic cancer continues to pose a major public health concern and clinical challenge. The incidence of the disease is nearly equivalent to the death rate associated with the diagnosis of pancreatic cancer. Thus, there exists a need for continued improvement in the diagnostic, therapeutic and palliative care of these patients. Surgeons play an integral role in the management of pancreatic cancer patients, with surgery providing the only potentially curative intervention for the disease. Specialized centers have reported improved hospital morbidity, mortality and survival after pancreaticoduodenectomy; however, disease-specific survival after surgical resection remains dismal. An emphasis therefore has been placed upon the accurate preoperative staging of patients in order to identify those patients who would benefit from a complete surgical resection. Surgical staging that incorporates the use of laparoscopic techniques now complements non-surgical methods of staging, including helical CT scans. While there is no defined preoperative staging approach, it is imperative that centers identify areas of expertise and experience with available modalities in any combination to effect accurate staging. Once patients have been accurately staged and deemed resectable, there exist various methods for resection of pancreas lesions, which include the standard "Whipple procedure," pylorus-preserving pancreaticoduodenectomy, regional pancreatectomy, total pancreatectomy, and en bloc vascular resection, where appropriate. Reconstructive techniques have been explored and include methods of pancreaticojejunostomy and pancreaticogastrostomy with or without pancreatic ductal stents and intraoperatively placed closed suction drains. Perioperative mortality following pancreaticoduodenectomy for cancer has a general reported incidence of 1% to 4% at high volume centers experienced with the operation. Morbidity however still remains high with that of delayed gastric emptying, pancreatic anastomotic leak or fistula, intraabdominal abscess, and hemorrhage as the leading reported complications. Researchers have investigated several agents and strategies to decrease or prevent the potential morbidity of these complications including the use of octreotide, drainage of the pancreatic bed and institution of early enteral feeding. Unfortunately, the majority of patients with pancreatic cancer present with either locally advanced or metastatic disease that precludes operative cure. The expected survival for these patients is usually less than six months from diagnosis. Therefore, a goal of therapy should be adequate palliation of symptoms of pain, biliary or duodenal obstruction and improvement of remaining quality of life with the least degree of morbidity possible.

Algorithms↗