Biomedical subjects
Publications and source records attributed to M Kulaylat.
Using a previously developed method (Ambrus, et al., 1991), we found that pentoxifylline and thalidomide potentiate each others antiangiogenic effect induced by human malignant melanoma cells in the cornea of Macaca arctoides monkeys.
Neutropenic enterocolitis (NE) is an unusual complication of neutropenia. Its presentation is dramatic, treatment is controversial, and the outcome may be devastating. The available literature about this entity is mainly case reports and autopsy studies. We have recently performed a celiotomy on a patient who developed sepsis and an acute surgical abdomen three days following chemotherapy and radiotherapy for a metastatic adenocarcinoma with no known primary tumor. At surgery he was found to have a boggy right and recto-sigmoid colon with a grossly normal transverse colon. Intraoperative colonoscopy revealed mucosal ulceration and necrosis extending from the dentate line to the cecum. A total abdominal colectomy, closure of the rectal stump, and an ileostomy was performed. Postoperatively, the patient recovered from the abdominal septic process only to succumb to multiple system organ failure secondary to pulmonary sepsis. Upon review of the literature, we found 65 cases of NE that were suspected or diagnosed in the antemortem state and confirmed at surgery or autopsy. In this review, we intend to analyze these case reports, summarize the salient features of the disease and outline the optimal therapeutic approach.
A series of pyrimido-pyrimidine derivatives were tested for their effect on membrane fluidity-deformability of human red blood cells and on human platelet aggregation. These agents were also tested for their intracellular cAMP increasing activity and proliferation inhibitory activity in neoplastic cells. The order of activity was established and clinical implications discussed. Several derivatives are under study as antineoplastic agents.
Pentoxifylline (Trental) is metabolized by red blood cells and the liver into seven metabolites. Metabolites I and V have significant hemorrheologic effects. They are both similar to pentoxifylline in their activity on red blood cell membrane fluidity. Metabolite I is more active than pentoxifylline in inhibiting ADP-induced platelet aggregation. Metabolite V is more active than pentoxifylline in inhibiting epinephrine-induced platelet aggregation.
Leucine (LEU) kinetics were assessed using a primed-continuous infusion of L-[1-14C]LEU in normal overnight-fasted male volunteers during a basal period and an experimental period where insulin (INS) was infused at either 0.6, 1.2, 2.5, 5.0, 10, or 20 mU.kg-1.min-1 with euglycemia maintained. Two protocols were used: 1) subjects were allowed to develop hypoaminoacidemia or 2) plasma essential amino acids (AA) were maintained near basal levels by frequently monitoring plasma LEU in conjunction with variable infusions of an AA solution (LEU infused = 0.41, 0.72, 0.93, 1.03, 1.31, and 1.35 mumol.kg-1.min-1 at escalating INS doses, respectively). Basal rates of LEU appearance (Ra), nonoxidative disappearance (NORd) and oxidative disappearance (OXRd) were similar in both protocols (means = 1.74, 1.40, and 0.36 mumol.kg-1.min-1, respectively). INS infusions without AA resulted in a progressive decrement in LEU Ra (14 to 45%), NORd (16-41%), and OXRd (3-56%) compared with basal values. The infusion of AA resulted in an additional reduction in endogenous Ra (P less than 0.01; approximately 100% suppression achieved at plasma INS greater than 1,000 microU/ml) and a blunting of NORd reduction (P less than 0.05) at each dose of INS. Observed differences in INS's suppression of LEU Ra between the two protocols suggests the existence of a component of whole body proteolysis that is highly dependent on circulating plasma AA. Therefore, hypoaminoacidemia associated with INS treatment would appear to blunt the responsiveness of INS's suppression of protein breakdown and in the presence of near basal plasma AA, proteolytic suppression by INS is enhanced.
Colonic perforation during flexible colonoscopy is a rare but recognized complication. We reviewed 4,593 colonoscopies performed from 1984 to 1989. The perforation rate for diagnostic colonoscopy was 0.17% (6/3,538) and for therapeutic colonoscopy it was 2% (21/1,055). Four perforations of the right colon occurred at a site proximal to the level of the impacted colonoscope. The lesions being evaluated were obstructive in nature: two diverticular strictures (sigmoid colon), one ischemic stricture (descending colon), and one annular carcinoma (descending colon). The four perforations occurred in the right colon and manifested as distension with pneumoperitoneum or retroperitoneal emphysema. Operative management included total abdominal colectomy in two patients (ileoproctostomy in one and ileostomy in one) and right colectomy in two. Outcome was favorable in all cases.
The role that amino acids play in regulating exogenous glucose infusion during hyperinsulinemia was examined in overnight-fasted volunteers. Each study consisted of both a 30-minute basal period and a 4-hour experimental period during which insulin was infused at either 0.6, 1.2, 2.5, 5.0, 10, or 20 mU/kg/min with euglycemia maintained. Two protocols were used. In the first (I), subjects were allowed to develop hypoaminoacidemia, and in the second (II), plasma amino acid levels were maintained near basal by frequently monitoring plasma leucine levels in conjunction with exogenous infusion of an L-amino acid solution. The amount of amino acids infused were 0.85 +/- 0.11, 1.53 +/- 0.17, 1.97 +/- 0.13, 2.18 +/- 0.50, 2.78 +/- 0.61, and 2.83 +/- 0.44 mg/kg/min at escalating insulin doses, respectively. When amino acids were infused, the amount of glucose required to maintain euglycemia was lower at each insulin dose used (4.5 +/- 0.3 vs 3.6 +/- 0.4, 7.6 +/- 0.5 vs 6.9 +/- 0.3, 10.4 +/- 1.0 vs 8.7 +/- 0.5, 13.3 +/- 0.8 vs 10.2 +/- 0.4, 14.7 +/- 0.8 vs 11.7 +/- 0.6, and 14.9 +/- 0.6 vs 11.8 +/- 0.8 mg/kg/min at escalating insulin doses, respectively; p less than 0.05). The calculated maximal infusion rates were 15.8 +/- 0.6 vs 12.6 +/- 0.4 mg/kg/min (protocol I vs II, p less than 0.001), while the concentrations required to achieve half-maximal rates were 153 +/- 22 and 134 +/- 22 microU/ml (p = ns), respectively.(ABSTRACT TRUNCATED AT 250 WORDS)
Seven patients with gastric leiomyosarcoma (LMS) and leiomyoblastoma (LMB) were seen at the American University of Beirut Medical Center in the period 1970-1983. The natural history, clinical presentation, radiologic findings, histopathologic features and treatment modalities of these patients are discussed. The anatomic location of the tumor had no relation to the occurrence and number of mucosal ulcers. Ulcerations were more frequent with endogastric than exogastric tumors. Histologic pattern, cell shape and number of mitotic figures were the basic morphological criteria for differentiating between LMS and LMB. Maintenance of a reasonable gastric reservoir and avoidance of total or near total gastrectomy are important factors affecting long term morbidity following surgical resection.