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Biomedical subjects

J V Sitzmann

Publications and source records attributed to J V Sitzmann.

116 records · Page 7Linked to original sources
PubMedDate not supplied

Vascular abnormalities following radio- and chemotherapy of hepatic neoplasms: CT angiographic findings.

Four patients (three with hepatocellular carcinoma and one with colorectal carcinoma metastatic to the liver) previously treated with chemotherapy or radiotherapy or both in an attempt to reduce tumor bulk prior to surgical resection were examined by CT angiography (CTA). Areas of abnormal enhancement and irregular vessels simulating tumor involvement proved to be free of neoplasm at surgery. Perfusion abnormalities and vascular irregularity on CTA following radiotherapy or chemotherapy should not be automatically considered as neoplastic. Tissue confirmation in such cases should be obtained to rule out treatment related hepatic parenchymal changes.

Adolescent↗
PubMedDate not supplied

Flow-mediated regulation of endothelin receptors in cocultured vascular smooth muscle cells: an endothelium-dependent effect.

The objective of this study was to determine the effect of pulsatile flow on endothelin (ET) receptor expression in vascular smooth muscle cells (VSMC) cocultured with endothelial cells (EC). Using a perfused transcapillary coculture system which permits the chronic exposure of cultured EC and VSMC to physiological shear stresses, cocultures were exposed to stepwise increases in flow up to (1) 2 ml/min (low flow: 0.5 dyn/cm2) or (2) 44 ml/min (high flow: 15 dyn/cm2) and maintained for 72 h before SMC and EC were harvested separately. There was a significant increase in [125I]-ET-1 binding in cocultured VSMC exposed to high flow as compared to low flow (Bmax: 75 +/- 22 vs. 152 +/- 10 fmol [125I]ET-1 bound/mg protein) in the absence of any change in the affinity (KD) of ET-1 for its receptor. ET-1 peptide mRNA levels were significantly decreased in EC exposed to high flow. The increase in [125I]ET-1 binding was associated with an increase in ET-A and ET-B receptor mRNA levels and was EC dependent as [125I]ET-1 binding in monocultured VSMC was the same, regardless of flow conditions. However, the amount of [125I]ET-1 binding on VSMC cultured in the absence of EC was significantly greater than that on cocultured VSMC. High flow caused a significant increase in endothelial nitric oxide synthase (NOS) activity in EC and prostacyclin levels in the perfusing medium. Flow-mediated upregulation of ET receptors was diminished by treatment with NG-nitro-L-arginine-methyl ester, a NOS inhibitor, whereas indomethacin, a cyclooxygenase inhibitor, had no significant effect. Collectively, these data suggest that flow-induced changes in ET receptor expression in VSMC are endothelium dependent and are in part mediated by nitric oxide. Modulation of ET receptor expression by EC may thus represent an important mechanism whereby hemodynamic forces regulate vessel wall function.

6-Ketoprostaglandin F1 alpha↗
PubMedDate not supplied

Nutritional support of the dysphagic patient: methods, risks, and complications of therapy.

The indications, methods, and complications of nutritional support of 90 patients admitted with a primary complaint of dysphagia were reviewed. Patients were divided into two groups based on etiology of dysphagia (central neurologic vs local mechanical dysfunction). All patients on admission exhibited marked malnutrition with an average weight loss of 12 +/- 9.8% body weight, serum transferrin 165 +/- 60.1 mg/dl, and albumin 3.2 +/- 0.85 mg/dl. All patients were placed on either enteral (63%) or parenteral (37%) nutrition. Twenty-seven percent of all patients suffered a complication of nutritional therapy. Patients with nasoenteric tubes had a 10% complication incidence (aspiration or endotracheal placement of tube) resulting in a 30% mortality rate; significantly higher (p less than 0.05) than seen with other modalities. Any form of upper enteric feeding (nasoenteric or gastrostomy) was associated with significantly increased (p less than 0.01) risk of aspiration pneumonia. It is concluded that patients admitted to hospital with dysphagia as the major complaint suffer from severe malnutrition, and that upper gastrointestinal intubation should not be employed for feeding until the dysphagia has resolved.

Adult↗
PubMedDate not supplied

Risk factors for central venous catheter-related vascular erosions.

Risk factors for superior vena cava perforations following central venous catheterization for total parenteral nutrition were identified in a retrospective study of 1058 catheters in 853 patients; 540 of these catheters were size 16-gauge (51%) and 518 size 14-gauge (49%). Of the size 14-gauge catheters, 274 (53%) were right-sided and 244 (47%) were left-sided subclavian catheters. Four patients (0.4%) had superior vena cava perforation. All had left-sided large bore 14-gauge catheters. All patients experienced acute symptoms and all had pleural effusions. There was no mortality directly related to vascular erosions. Two risk factors were identified for this complication: (1) catheters originating from the left side (p less than 0.05), or (2) large catheters (size 14-gauge or larger) (p less than 0.01). We conclude that large bore or left-sided central venous catheter placement represents an increased risk of superior vena cava perforation.

Adult↗
PubMedDate not supplied

Long-term central venous access vs other home therapies: complications in patients with acquired immunodeficiency syndrome.

One hundred and forty silicone catheters were inserted in 127 patients for long-term intravenous access with a cumulative follow-up time of 21,125 catheter-days (58 patient-years). Fifty-six patients had acquired immunodeficiency syndrome (AIDS); 44 were not AIDS patients and were receiving ambulatory home parenteral nutrition, whereas the remaining 27 did not have AIDS and were receiving home antibiotic therapy. Patients had a mean of 1.1 catheters inserted, and the rate of Hickman catheter-related sepsis was 0.18 per 100 catheter days or 0.6 septic episodes per patient year of treatment. Catheter-related sepsis was higher in AIDS patients (p < .01) and in patients receiving parenteral nutrition (p < .05) compared with those receiving antibiotic therapy. Prior catheter infection and AIDS were the most significant predictors of catheter infection (p < .01). Staphylococcus aureus was the most commonly isolated pathogen (61%) in AIDS patients. Fever (p < .001) and relative leukocytosis (p < .02) were the most common signs of infection. Only 14 infected catheters (37.8%) were salvaged by antibiotic therapy after the initial infection episode, and 6 of these catheters (42.9%) had recurrent multiple infections. In addition, inflammatory bowel disease was found to be a risk factor for venous thrombosis (p = .018). We conclude that because immunocompromised patients have a high risk of infection, catheter-related sepsis in these patients should be treated by catheter removal and antibiotics.

Acquired Immunodeficiency Syndrome↗
PubMedDate not supplied

Elemental diets may accelerate recovery from total parenteral nutrition-induced gut atrophy.

Prolonged bowel rest and total parenteral nutrition lead to gastrointestinal mucosal atrophy. The possibility that enteral diets of varying composition could have a beneficial effect in reversing total parenteral nutrition-associated gut atrophy was investigated. A group of male Sprague-Dawley rats were randomized to receive TPN for 10 days, followed by 10 days of elemental or regular food. The effects of these diets on body mass, gastro-intestinal index (intestinal weight divided by body weight), mucosal incorporation of titrated thymidine, and intestinal villi length were compared. Significant gut villi atrophy and use of gut weight occurred in rats receiving TPN and bowel rest compared with the fed control group. These changes were significantly reversed by elemental diets, but not by rat food diets. We conclude that elemental diets may enhance gut recovery after prolonged TPN and bowel rest in a rat model.

Animals↗
PubMedDate not supplied

Intensive chemoradiation followed by esophagectomy for squamous cell and adenocarcinoma of the esophagus.

PURPOSE: To determine the pathologic complete response rate, toxicity, and survival of patients with resectable squamous cell or adenocarcinoma of the esophagus treated with a 30-day preoperative chemoradiation regimen and surgical resection. PATIENTS AND METHODS: Fifty patients (16 squamous, 33 adeno, one undifferentiated) who had carcinoma of the esophagus (limited to the primary tumor and regional or celiac nodes) were treated with cisplatin 26 mg/m2/day continuous infusion days 1 through 5 and 26 through 30, 5-fluorouracil (5-FU) 300 mg/m2/day continuous infusion days 1 through 30, and radiation 44 Gy, 2 Gy/fx in 22 daily fractions, days 1 through 30, followed by esophagectomy. RESULTS: Forty-seven patients underwent esophagectomy (94% operability rate), and 45 had total gross removal of disease and negative margins of resection (90% resectability rate). Nineteen patients (40%) had a pathologic complete response (CR). Forty (80%) received 100% of the planned cisplatin dose, 29 (58%) received 100% of the planned 5-FU dose, and 40 (80%) received > or = 80% of the planned 5-FU dose. Forty-five (90%) received the planned 44-Gy radiation dose. Grade 3 or 4 neutropenia occurred in 60% of patients. The incidence of febrile neutropenia was 34%. There was one septic death during chemoradiation and no operative deaths. Weight loss requiring nutritional support occurred in 50% of patients, secondary to anorexia, dysphagia, and/or esophagitis. The survival of all registered patients at a median follow-up of 43 months was 2-year survival 58%, median 31.3 months. Survival analysis by histology showed no difference between the two histologic types (squamous vs adenocarcinoma). However, survival by pathologic response was significantly different: pathologic CR, 19 patients, 2-year survival 78%, median survival 58 months; and pathology positive, 28 patients, 2-year survival 46%, median survival 22.4 months. A Cox proportional hazards model and logistic regression analysis demonstrated a significant survival advantage for pathologic CRs and stage I disease versus higher-stage disease and a correlation between chemotherapy dose received and pathologic staging. DISCUSSION: This 30-day chemoradiation regimen followed by surgery resulted in a high pathologic complete response rate, 40%, and apparent survival advantage for this group. The median survival rate of 31.3 months and 2-year survival rate of 58% suggest that this regimen may improve survival over surgical treatment alone. Randomized trials with large accrual and statistical power are necessary to confirm our results and to determine optimal treatment.

Adenocarcinoma↗