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R J Nauta

Publications and source records attributed to R J Nauta.

49 records · Page 3Linked to original sources
PubMed1989

Selective vs routine use of intraoperative cholangiography. An argument.

We reviewed the course of 314 patients who underwent cholecystectomy at a University Hospital in 1985. Two hundred eighty-five patients underwent cholecystectomy for cholelithiasis. Preoperatively elevated liver function test results, history of jaundice or pancreatitis, or operative findings of palpable common bile duct stone or dilated extrahepatic ducts were criteria for indicated cholangiography. Of 142 patients who had cholangiography with negative results, only 31 were indicated by these criteria. In 93 patients not having cholangiography performed, the criteria were met in only 8 patients. Of 38 patients who underwent common bile duct exploration, only 29 had stones. As operative time, morbidity, and cost were demonstrably increased in patients undergoing cholangiography, a selective approach is advocated. The number of unnecessary common bile duct explorations might be cut by almost half, while the incidence of finding clinically unsuspected yet significant common bile duct stones is negligible.

Cholangiography↗
PubMed1988

Intraoperative interstitial radiation therapy for hepatic metastases from colorectal carcinomas.

Liver metastases from colorectal carcinomas occur frequently. While surgical resection offers the only hope for long-term cure, unsuspected bilobar metastases or extrahepatic metastatic disease may be found at laparotomy, precluding hepatic resection for cure. In this setting intraoperative interstitial hepatic irradiation using the Gamma Med II (Mick Radio-Nuclear Instruments, Bronx, New York) remote afterloading irradiator and an Iridium-192 source permits delivery of a tumoricidal dose to liver tumor(s) with a limited radiation dose to adjacent normal liver. Six patients underwent laparotomy for potential resection of hepatic metastases in a shielded operating room equipped with remote anesthesia monitoring capability and were found to be unresectable. An upper hand retractor facilitated liver exposure during the exploratory and subsequent radiation phases of the procedure. Intraoperative interstitial radiation therapy was performed in each patient. No significant complications occurred on follow-up from 2 to 9 months. Hepatic tumor regression or stabilization occurred on sonography and/or CT scan in each case with a median follow-up of 5 months. The technique offers the potential to ablate discrete tumor nodules within the liver. Ongoing clinical trials will determine the role of intraoperative interstitial radiation in the treatment of hepatic metastases.

Adenocarcinoma↗
PubMed1987

Intraoperative single-dose radiotherapy. Observations on staging and interstitial treatment of unresectable liver metastases.

Fourteen patients with a history of colonic cancer were evaluated for metastatic disease and were thought to have unresectable disease confined to the liver. Exploratory surgery revealed that two patients had extensive extrahepatic disease, and the procedure was terminated. In 12 patients, closed-end needles (diameter, 2.1 mm) were introduced into each nodule and connected to a 370-MBq (10-Ci) afterloading iridium source. Radiation doses were dependent on nodule size, providing minimum doses of 20 Gy (2000 rad) to the lesion's periphery with rapid radiation falloff avoiding toxic effects to adjacent normal tissue. The maximum number of nodules treated in one patient was 11. The largest nodule treated measured 9 x 6.5 x 6 cm. Cholecystectomy in four patients allowed precise implantation and obviated biliary fistula. Preoperative computed tomography underestimated the number of hepatic metastases in all cases but one, and treatment-induced computed tomographic alterations further limited its utility. Radiation treatment was well tolerated, and the median hospitalization was eight days. Of ten patients whose preoperative carcinoembryonic antigen values exceeded 10 ng/dL, the values in six patients decreased postoperatively.

Adult↗
PubMed1987

The effects of liver directed radiotherapy and chemotherapy on liver function tests and hematological parameters in patients with surgically resected colon cancer: findings from the Gastrointestinal Tumor Study Group.

The effects on liver function tests of liver-directed radiation (RT) and systemic chemotherapy (CT) were examined at 6 months after initiation of treatment on two Gastrointestinal Tumor Study Group protocols. Data from patients on protocol GI 6175 (adjuvant CT or no adjuvant therapy) were used to evaluate the effect of CT alone, and data from patients on protocol GI 6179 (adjuvant CT plus liver directed RT or no adjuvant therapy) were used to evaluate the combined effects of CT and RT. Finally, data from patients on GI 6179 who received less than protocol specified RT doses were used to determine whether minor differences in dose are detectable via liver function tests. In 40 patients receiving CT, the serum level of alkaline phosphatase was not significantly increased (p = 0.14) compared to that of control patients whereas the level of serum glutamate oxoloacetate transaminase was significantly elevated (p = 0.03). In 31 patients receiving both CT and RT, both alkaline phosphatase and SGOT were significantly elevated (both p = 0.03). In addition, in 19 patients who received less than full RT doses, the changes in dose were not detectable from those patients who received full dose (all p greater than 0.10). In summary, CT alone may elevate hepatocellular enzymes, whereas a combination of CT and liver-directed RT is associated with a significant increase in both SGOT and alkaline phosphatase. Small alterations in the dose of volume of RT are not detectable by liver function test variations.

Alkaline Phosphatase↗
PubMed1986

Crohn's appendicitis in an incarcerated spigelian hernia.

A patient with incarcerated Crohn's appendicitis and a spigelian hernia is presented, representing the challenge in diagnosis, incision choice, and choice of definitive surgical procedure. While it is unlikely that the report of such a patient's course will make prospective recognition of this rare entity more likely, a systematic approach to this patient has allowed a satisfactory result with minimal complications.

Adult↗
PubMed1986

Observation versus operation for abdominal pain in the right lower quadrant. Roles of the clinical examination and the leukocyte count.

In-hospital observation of patients with abdominal pain in the right lower quadrant has been suggested as a means of improving diagnostic accuracy and of decreasing the incidence of negative laparotomy. An analysis of 97 patients brought to the operating room over a 12 month period in a university hospital suggests that patients with the classic pattern of migratory pain, rebound tenderness, and an increased number of metamyelocytes in the peripheral blood smear most likely require operation. Leukocytosis alone was not predictive of a surgically remediable disease, which suggests that a period of observation in patients with atypical patterns of pain and no peritoneal signs is a sound treatment plan.

Abdomen, Acute↗
PubMed1982

Clinical staging and the tendency of malignant pleural mesotheliomas to remain localized.

Thirty-two patients who had been treated for diffuse, malignant pleural mesotheliomas were retrospectively staged according to the system of Butchart. Nineteen of the 26 patients who were seen with disease confined to one hemithorax have died. Twelve patients died without progression to a higher clinical stage, and only 1 patient died of systemic metastases. Nineteen of the 32 patients died of local tumor invasion. Regimens containing Adriamycin (doxorubicin hydrochloride) appeared to prolong the survival of patients with epithelial-type tumors. Combination chemotherapy, designed to treat soft-tissue sarcomas, produced partial responses in a small number of patients.

Doxorubicin↗
PubMedDate not supplied

Dynamic CT vs 0.5 T MR imaging in the detection of surgically proven hepatic metastases.

Seventeen patients with 52 surgically proven hepatic metastases were studied preoperatively with dynamic CT and 0.5 T magnetic resonance (MR). Dynamic CT detected 38 metastases (73%), and the combination of short echo time (T1-weighted) and T2-weighted pulse sequences detected 46 lesions (88%). Magnetic resonance was also superior at assessing potential resectability. This study suggests that MR excels in detecting and anatomically localizing individual hepatic metastases.

Humans↗
PubMedDate not supplied

In vitro effect of 5-fluorouracil, verapamil and hyperthermia on the human pancreatic adenocarcinoma cell line ASPC-1.

The purpose of this study was to assess the efficacy of verapamil (20 microM) and hyperthermia (42 degrees C) as modifiers of 5-fluorouracil (5-FU) used at different concentrations, in inhibiting the growth of human pancreatic adenocarcinoma cells. Combined verapamil and hyperthermia treatment significantly decreased cell count by 63.8% when compared to the control. Verapamil drastically enhanced the growth inhibitory effect of 5-FU at all concentrations. At high-concentration 5-FU (50 micrograms/ml), verapamil and hyperthermia had a synergistic growth-inhibitory effect and caused a significant decrease in cell count by 81.4% in comparison to the control. The modalities analyzed in this study require further investigation and have potential for clinical applicability to pancreatic cancer therapy in the future.

Adenocarcinoma↗
PubMedDate not supplied

Apoptosis induced by hyperthermia and verapamil in vitro in a human colon cancer cell line.

The aim of this study was to determine the mechanisms responsible for the growth inhibitory effect of hyperthermia and verapamil in human colon cancer cell line HT-29. Apoptotic cell death was verified by flow cytometry analysis. The effect of treatment with hyperthermia and verapamil on the expression of apoptosis-associated proteins including Bcl-2, p53, bax, and c-Myc was studied by Western blot analysis. Changes in intracellular calcium homeostasis was analysed by fluorescence microscopy. The combination of 42 degrees C hyperthermia and verapamil caused a significant delay of human colon cancer cell proliferation as a result of apoptosis. Administration of these agents alone did not cause any cell inhibitory effect. Our experiments have shown that HT-29 cells constitutively express apoptosis-promoting proteins, such as Bax and c-Myc, while they fail to produce Bcl-2. Therefore, we hypothesize that HT-29 cells must have Bcl-2 independent pathways to protect cells against death-inducing signals. Also, apoptosis of HT-29 cells produced by hyperthermia in the presence of verapamil is a p53-independent process. Verapamil, when it did not act as a calcium channel blocker or inhibitor of release from intracellular storages under hyperthermic conditions, accelerated the increase of [Ca2+]i in HT-29 cells which resulted in programmed cell death (apoptosis).

Apoptosis↗
PubMedDate not supplied

Apoptosis of human primary and metastatic colon adenocarcinoma cell lines in vitro induced by 5-fluorouracil, verapamil, and hyperthermia.

Combined verapamil(V) and hyperthermia(HT) showed a significant decrease in HT29 and SW-620 cell counts by 61.5% and 77.6%, respectively, when compared to control. V in conjunction with 5-FU significantly reduced HT-29 count by 37% in comparison to 5-FU alone, and did not enhance the growth inhibitory effect of 5-FU on SW-620. HT did not enhance the growth inhibition seen with 5-FU treatment alone on HT-29, while this combination significantly decreased SW-620 cell count by 28.9% in comparison to administration of 5-FU alone. Joint administration of V and HT with 5-FU appeared to have a possible synergistic effect and reduced HT-29 count by 90% when compared to control. 5-FU alone or in different combinations with V and HT, as well as combination V+HT, results in apoptosis.

Adenocarcinoma↗