Alan Lefor

Prof. Alan Lefor

Department of Surgery, Jichi Medical University, Tochigi, Japan
orcid

Research Focus & Metrics

Academic Career Length

48Years (1979-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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1 January 2014 in World Journal of Gastroenterology
Verified
Journal Article
Open access
SKShigeyoshi Kijima
Shigeyoshi Kijima
TSTakahiro Sasaki
Takahiro Sasaki
KNKoichi Nagata
Koichi Nagata
KUKenichi Utano
Kenichi Utano
Alan LeforAlan Lefor
Alan Lefor
HSHideharu Sugimoto
Hideharu Sugimoto
Imaging studies are a major component in the evaluation of patients for the screening, staging and surveillance of colorectal cancer. This review presents commonly encountered findings in the diagnosis and staging of patients with colorectal cancer using computed tomography (CT) colonography, magnetic resonance imaging (MRI), and positron emission tomography (PET)/CT colonography. CT colonography provides important information for the preoperative assessment of T staging. Wall deformities are associated with muscular or subserosal invasion. Lymph node metastases from colorectal cancer often present with calcifications. CT is superior to detect calcified metastases. Three-dimensional CT to image the vascular anatomy facilitates laparoscopic surgery. T staging of rectal cancer by MRI is an established modality because MRI can diagnose rectal wall laminar structure. N staging in patients with colorectal cancer is still challenging using any imaging modality. MRI is more accurate than CT for the evaluation of liver metastases. PET/CT colonography is valuable in the evaluation of extra-colonic and hepatic disease. PET/CT colonography is useful for obstructing colorectal cancers that cannot be traversed colonoscopically. PET/CT colonography is able to localize synchronous colon cancers proximal to the obstruction precisely. However, there is no definite evidence to support the routine clinical use of PET/CT colonography.

1 December 2008 in Diseases of the Colon & Rectum
Verified
Journal Article
Closed access
STShingo Tsujinaka
Shingo Tsujinaka
FKFumio Konishi
Fumio Konishi
YKYutaka J. Kawamura
Yutaka J. Kawamura
MSMasaaki Saito
Masaaki Saito
NTNaoshi Tajima
Naoshi Tajima
Alan LeforAlan Lefor
Alan Lefor
Er between April 2001 and April 2007 were included. Obesity was defined by visceral fat area ≥130 cm2 or body mass index ≥25 kg/m2, and the variables were compared for obese and nonobese patients. Results: There were 68 (51.1 percent) obese patients according to visceral fat area and 27 (20.3 percent) according to body mass index. Using either definition, obese patients had a significantly longer operative time compared with nonobese patients. Patients classified as obese by visceral fat area had a significantly higher incidence of wound infection (20.6vs.4.6 percent;P= 0.006) and overall complication rates (32.4vs.12.3 percent,P= 0.006) compared with nonobese patients, whereas there was no significant difference when classified by body mass index. Postoperative hospital stay was significantly longer in obese patients compared with nonobese patients classified by visceral fat area (median 10.5vs.9 days;P= 0.007), whereas it was not statistically different when classified by body mass index. Conclusion: Visceral fat area is a more useful parameter than body mass index in predicting surgical outcomes after laparoscopic colectomy for sigmoid colon cancer. Presented at the Biennial Congress of International Society of University Colon and Rectal Surgeons, Istanbul, Turkey, June 25 to 28, 2006. © The ASCRS 2008...

1 January 1995 in Journal of Clinical Oncology
Verified
Journal Article
Closed access
BEB J Eastridge
B J Eastridge
Alan LeforAlan Lefor
Alan Lefor
PURPOSE: We undertook this study to review our experience with indwelling vascular access devices in cancer patients to identify factors associated with complications. PATIENTS AND METHODS: A total of 322 indwelling devices were placed in 274 cancer patients by a single surgeon. Devices were placed via percutaneous insertion in 72% (231 of 322) and via venous cutdown in 28% (91 of 322). We placed external catheters in 209 of 322 patients (65%) and subcutaneous infusion ports in 113 of 322 (35%). RESULTS: Pneumothorax occurred in four of 231 (1.7%) of the percutaneously placed devices. Postoperative complications included sepsis and thrombosis, which necessitated premature removal of the devices. Device related sepsis occurred in 28 of 209 patients (13%) with catheters and six of 113 patients (5%) with subcutaneous ports. Thrombosis occurred in 21 of 209 patients (10%) with catheters and seven of 113 (6%) with subcutaneous ports. In 15 of 19 devices removed for thrombosis, the tip was above the T3 level. Seventeen devices were placed in the saphenous vein, with a complication rate similar to that observed in upper-body devices. CONCLUSION: We found a significantly (P < .05, chi 2 analysis) increased incidence of thrombotic complications in patients with triple-lumen catheters (10 of 48) compared with double-lumen catheters (11 of 160), as well as a significantly (P < .05) decreased mean time until catheter failure (40 v 146 days). We also observed a significant increase in the rate of thrombosis in patients with a catheter tip above the T3 level. We therefore recommend the use of fluoroscopy at the time of placement to assure adequate catheter length and tip position and the use of triple-lumen catheters only when necessary for concurrent drug administration.

16 August 2012 in Transplantation Research
Verified
Journal Article
Open access
PDF file
EKEiji Kobayashi
Eiji Kobayashi
SHShuji Hishikawa
Shuji Hishikawa
TTTakumi Teratani
Takumi Teratani
Alan LeforAlan Lefor
Alan Lefor
To improve the welfare of experimental animals, investigators seek to respect the 3R principle (Replacement, Reduction, and Refinement). Even when large animal studies are essential before moving to clinical trials, it is important to look for ways to reduce the number of experimental animals used. At the Center for the Development of Advanced Medical Technology, we consider ‘medical’ pigs to be ideal preclinical model systems. We have been using both wild-type and genetically modified pigs. We began using this approach about 10 years ago with a ‘total pig system’ to model human health and disease for the purposes of both medical skill education and the development of new devices and therapeutic strategies. At our Center, medical students and residents use pigs to gain experience with surgical skills and train for emergency procedures after appropriate simulation training. Senior clinicians have also used these models to advance the development of innovative tools for endo- and laparoscopic procedures. The Center focuses on translational research for organ transplantation and stem cell therapy. Several pig models have been established for liver, intestine, kidney, pancreas, and lung transplantation. Mesenchymal stromal cells have been established in green fluorescent protein- and red fluorescent protein-transgenic pigs and tested to trans-differentiate organogenesis. A program to establish induced pluripotent stem cells in the pig is ongoing at our Center. Here, we review our 10 years of activity in this field. Based on our experience in surgical education and research, experimental pigs are valuable models in translational research.

1 January 2009 in Journal of Nutritional Science and Vitaminology
Verified
Journal Article
Closed access
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KSKuniyasu Soda
Kuniyasu Soda
YKYoshihiko Kano
Yoshihiko Kano
MSMasako Sakuragi
Masako Sakuragi
KTKoichi Takao
Koichi Takao
Alan LeforAlan Lefor
Alan Lefor
FKFumio Konishi
Fumio Konishi
Although the intracellular de novo synthesis of the polyamines decreases with age, there is no similar trend in blood polyamine levels, but rather there is wide individual variability. We hypothesized that dietary polyamines attenuate a decrease in blood polyamine levels with age and augment the previously observed individual variability. The effect of a polyamine rich diet, in both mice and humans, on blood polyamine concentrations was examined in this study. Jc1:ICR male mice were fed test diets containing 3 different polyamine concentrations. Healthy human male volunteers added 50 to 100 g of the polyamine-rich fermented soybean product, natto, to their daily intake. After 26 wk, the mean blood spermine concentration in mice receiving the test diet with high polyamine concentrations was 10.1±2.4 μmol/L, while the mean concentrations found in mice fed with a diet with normal or low polyamine concentrations were 5.2±0.9 and 4.7±0.5 μmol/L, respectively (p<0.05). A mean daily intake of 66.4±3.7 g (range=46.4-89.3 g) of natto for 2 mo by human volunteers increased the mean blood spermine concentration by a factor of 1.39 (n=10) (p<0.01), while in control volunteers (n=7), asked to exclude polyamine-rich foods from their diet, blood spermine concentration remained unchanged. The individual variability of blood polyamine levels was enhanced after polyamine intake in mice and, to a lesser extent, in humans. The long-term oral intake of enhanced polyamine diets increases blood polyamine levels in both mice and humans.

20 March 2021 in Diagnostics
Verified
Journal Article
Open access
PDF file
JUJun Ushio
Jun Ushio
AKAtsushi Kanno
Atsushi Kanno
EIEriko Ikeda
Eriko Ikeda
KAKozue Ando
Kozue Ando
HNHiroki Nagai
Hiroki Nagai
HYHironori Yamamoto
Hironori Yamamoto
The number of new cases of pancreatic ductal adenocarcinoma is increasing with a cumulative total of 495,773 cases worldwide, making it the fourteenth most common malignancy. However, it accounts for 466,003 deaths per year and is the seventh leading cause of cancer deaths. Regional differences in the number of patients with pancreatic ductal adenocarcinoma appear to reflect differences in medical care, as well as racial differences. Compared to the prevalence of other organ cancers in Japan, pancreatic ductal adenocarcinoma ranks seventh based on the number of patients, eighth based on morbidity, and fourth based on the number of deaths, with a continuing increase in the mortality rate. Risk factors for developing pancreatic ductal adenocarcinoma include family history, genetic disorders, diabetes, chronic pancreatitis, and intraductal papillary mucinous neoplasms. An issue that hinders improvement in the prognosis of patients with pancreatic ductal adenocarcinoma is the development of a strategy to identify patients with these risk factors to facilitate detection of the disease at a stage when intervention will improve survival.