Laparoscopic gastrectomy with regional lymph node dissection for upper gastric cancer

BACKGROUND

The technique and results of laparoscopic gastrectomy in 110 patients with gastric cancer located in the upper third of the stomach are presented.

METHODS

Proximal gastrectomy was performed for lesions in the upper third of the stomach, and total gastrectomy for those that spread over both the upper and middle third. D1 and D2 lymph node dissection was undertaken in patients with T1 or T2 lesions. Anastomosis of the oesophagus was performed intracorporeally using a conventional circular stapling device or a laparoscopic linear stapler.

RESULTS

Median operating time was 247 min for proximal gastrectomy and 285 min for total gastrectomy; median blood loss was 207 and 334 ml respectively. A median of 23 lymph nodes was harvested from patients in the proximal gastrectomy group and 34 from those having a total gastrectomy. There was minimal morbidity and fast recovery after surgery. Postoperative recurrence occurred in only one patient, giving a recurrence rate of 0.9 per cent.

CONCLUSION

Laparoscopic gastrectomy for upper gastric cancer appears to be a safe and curative procedure.

Continuous infusion of 5-fluorouracil with versus without low-dose, consecutive administration of cisplatin in advanced colorectal cancer. A prospective randomized phase II study

Recently, the treatment of advanced gastric cancer by continuous infusion of 5-fluorouracil (5-FU) with low-dose cisplatin (CDDP) has improved efficacy without severe toxicities. The possible effectiveness of 5-FU+low-dose CDDP for colorectal cancer (CRC) is intriguing. One hundred fifty-five patients with far-advanced CRC including at least one measurable lesion were enrolled in a prospective randomized clinical trial funded by the Japanese Foundation for Multidisciplinary Treatment of Cancer. These patients were assigned to the two arms to assess the value of low-dose CDDP when added to a continuous intravenous infusion of 5-FU at a dose of 300 mg/m(2)/24 hrs in a one-week cycle consisting of 5 days of treatment and 2 days of rest for at least 12 weeks. CD-DP was given intravenously at a dose of 3 mg/m(2) on days 1-5 and days 8-12, and then at a dose of 7 mg/m(2) twice a week. Three patients were excluded from the trial. The response rate in the 5-FU+low-dose CDDP arm (n=75) was significantly higher than that in the 5-FU arm (n=77) (25.3% vs. 11.7%; P = 0.037). There was no significant difference in the median overall survival time between the 5-FU+low-dose CDDP arm and the 5-FU arm (479 and 491 days, respectively). Grades 3/4 toxicities occurred infrequently in both arms. The quality of life was almost the same between the arms. Low-dose CDDP improved the response rate while keeping toxicities within clinically acceptable limits. However, this combined treatment did not confer a survival advantage over treatment with continuous infusion of 5-FU alone for patients with far-advanced CRC; that might be attributable to the short CDDP administration setting of 12 weeks.

Triangulating stapling technique for reconstruction after colectomy

BACKGROUND/AIMS

To retrospectively compare the triangulating stapling technique for colocolonic anastomosis with hand-sewn anastomosis and functional end-to-end anastomosis.

METHODOLOGY

Data from 646 patients who underwent colectomy for cancer from 1993 to 2004 were extracted by chart review. Patients were divided into three groups based on the type of anastomosis: handsewn (n=233), functional end-to-end (n=71), and the triangulating stapling method (n=346). Demographic data and clinical characteristics of the three groups were similar.

RESULTS

Anastomotic leakage was significantly more common in the hand-sewn group than the triangular stapling group (hand-sewn; 3.0%, functional end-to-end; 2.8%, triangulating, 0.6%) (P < 0.05). No patient developed bleeding or stenosis at the anastomosis, and the incidence of wound infection was equivalent among the three groups. One death due to anastomotic failure occurred in each of the functional end-to-end and triangulating stapling groups. The cost of triangulating stapling was approximately Yen 36,000 lower than the cost of the functional end-to-end anastomosis.

CONCLUSIONS

The triangulating stapling technique is an attractive alternative to other methods for creating a colocolonic anastomosis.

Laparoscopic distal gastrectomy with regional lymph node dissection for gastric cancer

BACKGROUND

Recent advances in surgical techniques have led to widespread acceptance of laparoscopic gastrectomy for gastric cancer. We performed distal gastrectomy with regional lymph node dissection in 235 patients with gastric cancer located in the middle and lower third of the stomach.

METHODS

In 171 cases, reconstruction was done using the Billroth I method intracorporeally and the aid of laparoscopic linear stapling devices. The Billroth II and Roux-en-Y methods were used in the remaining 56 and eight patients, respectively,

RESULTS

Patients who underwent laparoscopic distal gastrectomy had a more rapid postoperative recovery than those treated via the open approach. Postoperative complications with this technique were within a permissible range. In terms of the survival curve, there was no statistical difference between the laparoscopic group diagnosed as clinical T2N0 (c T2N0) Preoperatively and the open group.

CONCLUSION

The laparoscopic technique is not only less invasive, but is also similarly safe and curative compared to open gastrectomy.

Altered expression of topoisomerase IIalpha contributes to cross-resistant to etoposide K562/MX2 cell line by aberrant methylation

KRN 8602 (MX2) is a novel morpholino anthracycline derivative having the chemical structure 3′-deamino-3′-morpholino-13-deoxo-10-hydroxycarminomycin hydrochloride. To investigate the mechanisms of resistance to MX2, we established an MX2-resistant phenotype (K562/MX2) of the human myelogeneous leukaemia cell line (K562/P), by continuously exposing a suspension culture to increasing concentrations of MX2. K562/MX2 cells were more resistant to MX2 than the parent cells, and also showed cross-resistance to etoposide and doxorubicin. Topoisomerase (Topo) IIα protein levels in K562/MX2 cells were lower of those in K562/P cells on immunoblot analysis and decreased expression of Topo IIα mRNA was seen in K562/MX2 cells. Topoisomerase II catalytic activity was also reduced in the nuclear extracts from K562/MX2 cells when compared with K562/P cells. Aberrant methylated CpG of Topo IIα gene was observed in K562/MX2 cells when compared with the parent line on methylation-specific restriction enzyme analysis. To overcome the drug resistance to MX2 and etoposide, we investigated treatment with 5-Aza-2′-deoxycytidine (5AZ), which is a demethylating agent, in K562/MX2 cells. 5-Aza-2′-deoxycytidine treatment increased Topo IIα mRNA expression in K562/MX2 cells, but not in K562/P cells, and increased the cytotoxicity of MX2 and etoposide. Methylated CpG was decreased in K562/MX2 cells after 5AZ treatment. We concluded that the mechanism of drug resistance to MX2 and etoposide in K562/MX2 cells might be the combination of decreased expression of Topo IIα gene and increased methylation, and that 5AZ could prove to be a novel treatment for etoposide-resistant cell lines, such as K562/MX2.

Electron microscopic studies on the occurrence of activated neutrophils in peripheral blood of children with acute leukemias

Peripheral blood (PB) cells are examined to assess cellular maturity and the degree of bone marrow abnormality in children with acute leukemias. During the ultrastructural assessments of PB cells in these children, we noted a frequent occurrence of activated neutrophils. This phenomenon had not been reported previously. We here report for the first time the identification of activated neutrophils in PB of children with acute leukemias. To examine the impact of activated neutrophils, we compared two groups of children including 18 with acute lymphoblastic leukemia (ALL) and 7 with acute myelogenous leukemia (AML) by an ultrastructural leukocyte count method. Many cases (50%) showed more than 30% activated neutrophils per total neutrophil count in PB. Activated neutrophils were elongated or amoeboid-shaped cells ranging from 13-18 microns in greater diameter with a decreased number of granules in the cytoplasm. A significantly higher rate of activated neutrophils was observed in ALL as compared with AML (median: 42.97% vs. 10.64%). Non-leukemic hospitalized (n =3) and healthy (n = 3) control cases showed a median rate of 3.32% activated neutrophils in PB. These findings reveal that a significantly high rate of activated neutrophils occurs in PB of children with ALL which may be exploited in the diagnostic assessment of children with acute leukemias.

A novel laparoscopic technique for stapled colon and rectal anastomosis

BACKGROUND

We present new techniques of stapling anastomosis at laparoscopic colorectal surgery with retrospective review of data.

METHODS

A triangulating stapling technique (T method) was performed in 101 laparoscopic colectomies. Adouble stapling technique (DST) with rectal division by a conventional linear stapler (Abd method) was used in 5 cases of upper/middle rectal cancers and subsequent eversion of the distal rectum from the anus (Ev method) was used for 4 low rectal cancers. Four hundred ninety-six colectomies and 280 rectal surgeries were reviewed.

RESULTS

Leakage was lower in the T group (0.5%, n=196) than in the hand-sewn group (3.0%, n=233). Leakage of the DST using a laparoscopic linear stapler (12.1%, n=91) was significantly higher than with conventional DST (2.1%, n=189). There was no leakage with either Abd method or Ev method. The T-method is acceptable after laparoscopic colectomy.

CONCLUSION

New methods of rectal division using conventional devices are expected to yield reliable anastomosis at laparoscopic rectal surgery.

Laparoscopic distal gastrectomy with regional lymph node dissection for gastric cancer

Recently, a minimally invasive operation for gastric malignancies has been advocated, and the laparoscopic operation is noted as a technique that increases the quality of life. We performed distal gastrectomy with regional lymph node dissection on 160 cases of gastric cancer located in the middle or lower third of the stomach. In 123 cases, Billroth I reconstruction was performed intracorporeally using the quadrilateral (square) stapling technique with a laparoscopic linear stapling device to prevent postoperative anastomotic bleeding and stenosis. In the remaining 37 cases, the Billroth II method was performed with a linear stapling device [1]. This technique is not only less invasive but also as safe as open gastrectomy, which was performed on 100 gastric cancer cases of similar staging.

Extrasynaptic NMDARs oppose synaptic NMDARs by triggering CREB shut-off and cell death pathways

Here we report that synaptic and extrasynaptic NMDA (N-methyl-D-aspartate) receptors have opposite effects on CREB (cAMP response element binding protein) function, gene regulation and neuron survival. Calcium entry through synaptic NMDA receptors induced CREB activity and brain-derived neurotrophic factor (BDNF) gene expression as strongly as did stimulation of L-type calcium channels. In contrast, calcium entry through extrasynaptic NMDA receptors, triggered by bath glutamate exposure or hypoxic/ischemic conditions, activated a general and dominant CREB shut-off pathway that blocked induction of BDNF expression. Synaptic NMDA receptors have anti-apoptotic activity, whereas stimulation of extrasynaptic NMDA receptors caused loss of mitochondrial membrane potential (an early marker for glutamate-induced neuronal damage) and cell death. Specific blockade of extrasynaptic NMDA receptors may effectively prevent neuron loss following stroke and other neuropathological conditions associated with glutamate toxicity.

Accelerated reendothelialization with suppressed thrombogenic property and neointimal hyperplasia of rabbit jugular vein grafts by adenovirus-mediated gene transfer of C-type natriuretic peptide

BACKGROUND

Vein graft disease limits the late results of coronary revascularization. C-type natriuretic peptide (CNP) inhibits the growth of vascular smooth muscle cells. Given the effects of CNP on cGMP cascade, we hypothesized that transfected CNP genes modulate endothelial repair and thrombogenicity in the vein graft.

METHODS AND RESULTS

Autologous rabbit jugular vein grafts were incubated ex vivo in a solution of adenovirus vectors containing CNP gene (Ad.CNP) or Escherichia coli lac Z gene (Ad.LacZ) and then interposed in the carotid artery. Reendothelialization, mural thrombi formation, and intima/media ratio were evaluated on the 14th and 28th postoperative days. More reendothelialization was seen in Ad.CNP-infected grafts than in Ad.LacZ-infected grafts both at 14 days (0.81+/-0.05 versus 0.30+/-0.14, P<0.01) and at 28 days (0.96+/-0.01 versus 0.45+/-0.08, P<0.001). The mural thrombus area was smaller in Ad.CNP-infected grafts than in Ad.LacZ-infected grafts. Neointimal thickening was significantly suppressed in the Ad.CNP group. The in vitro wound assay with human coronary artery endothelial cells revealed significant potentiation of the wound repair process by CNP and atrial natriuretic peptide administration.

CONCLUSIONS

Infected Ad.CNP accelerated reendothelialization and suppressed thrombosis and neointimal hyperplasia. The method may potentially prevent vein graft disease in patients undergoing coronary artery revascularization.

Coordinate regulation of endothelin and adrenomedullin secretion by oxidative stress in endothelial cells

To elucidate the significance of oxidative stress in the modulation of endothelial functions, we examined the effects of H(2)O(2) on the expression of two endothelium-derived vasoactive peptides, endothelin (ET) and adrenomedullin (Am), and their interaction. H(2)O(2) dose dependently suppressed ET secretion and ET-1 mRNA expression in bovine carotid endothelial cells (ECs). Menadion sodium bisulfate, a redox cycling drug, also decreased ET secretion in a dose-dependent manner. Catalase, a H(2)O(2) reductase, and dl-alpha-tocopherol (vitamin E) significantly inhibited H(2)O(2)-induced suppression of ET secretion. Downregulation of ET-1 mRNA under oxidative stress was regulated at the transcriptional level. In contrast, H(2)O(2) increased Am secretion (and its mRNA expression) accompanied by the augmentation of cAMP production. Am, as well as 8-bromo-cAMP and forskolin decreased ET secretion in a dose-dependent fashion. Furthermore, an anti-Am monoclonal antibody that we developed abolished H(2)O(2)-induced suppression of ET secretion at 6-24 h after the addition of H(2)O(2). H(2)O(2) increased the intracellular Ca(2+) concentration ([Ca(2+)](i)). Moreover, treatment with ionomycin, a Ca(2+) ionophore, and thapsigargin, an inhibitor of endoplasmic reticulum ATPase, decreased ET secretion dose dependently for 3 h. These results suggest that the production of ET was decreased via activation of the Am-cAMP pathway and by the elevation of [Ca(2+)](i) under oxidative stress. These findings elucidate the coordinate expression of two local vascular hormones, ET and Am, under oxidative stress, which may protect against vascular diseases.

Thiazolidinediones, peroxisome proliferator-activated receptor gamma agonists, regulate endothelial cell growth and secretion of vasoactive peptides

Insulin resistance has been highlighted as a common causal factor for glucose intolerance, hypertension and dyslipidemia, all of which are cardiovascular risk factors. A new class of antidiabetic agents, thiazolidinediones (TZDs), has been developed and demonstrated to improve insulin sensitivity. TZDs are high affinity ligands for peroxisome proliferator-activated receptor gamma (PPARgamma), the crucial transcription factor for adipocytes. Recent studies showed that PPARgamma is also expressed in monocytes/macrophages and is suggested to be involved in atherosclerosis. We could detect PPARgamma gene transcript in several cultured endothelial cells (human aortic endothelial cells (HAoECs), human coronary artery endothelial cells (HCAECs), human umbilical vein endothelial cells (HUVECs) and bovine carotid artery endothelial cells (BAECs)) as well as human coronary arteries we examined. Since endothelial dysfunction is critical for atherosclerosis, we investigated the effects of TZDs, troglitazone (TRO) and pioglitazone (PIO), on endothelial cell growth and secretion of C-type natriuretic peptide (CNP), which we demonstrated as a novel endothelium-derived relaxing peptide, and endothelin (ET), a potent vasoconstrictor, using HAoECs, HCAECs, HUVECs and BAECs. When all these cultured endothelial cells were daily treated with TRO and PIO for 5 days, both TRO and PIO (10(-8)M) significantly stimulated (3)H-thymidine incorporation of all these endothelial cells. In contrast, higher dose of TRO and PIO (10(-5)M) significantly suppressed DNA synthesis. TRO and PIO also exerted the compatible effect on the increase of cell numbers. TRO and PIO significantly enhanced CNP secretion from BAECs. In contrast, ET secretion from BAECs was suppressed by both TRO and PIO in a dose-dependent manner. The results of the present study suggest that TZDs modulate endothelial functions, including regulation of endothelial cell growth and secretion of endothelium-derived vasoactive substances, which affect vascular tone and remodeling in the process of atherosclerosis.

Usefulness of bronchoalveolar lavage for the diagnosis and treatment of refractory pneumonia in a patient with Kostmann syndrome, a severe congenital neutropenia

An 11-year-old girl with Kostmann syndrome developed refractory pneumonia. Culture of oral discharge, throat-swab specimens, and blood could not identity the causative organism, and systemic antimicrobial therapy failed to achieve improvement. We then performed diagnostic bronchoalveolar lavage (BAL) and culture of BAL fluid (BALF) yielded Pseudomonas aeruginosa. Therapeutic BAL using gentamicin produced a striking improvement of her pneumonia.

CONCLUSION

In immunocompromised children with pneumonia, BAL helps to identify the causative organism. If the patient is unresponsive to systemic antimicrobial therapy, BAL using antimicrobial agents is also worth trying.

Laparoscopy-assisted resection for jejunal carcinoma

Laparoscopic surgery has been applied in small bowel resections for various diseases, such as obstruction including intussusception, diverticula, and tumors. We report a case of successful resection of a jejunal carcinoma that was diagnosed before surgery by using a laparoscopy-assisted technique.

Expression of carcinoembryonic antigen in peripheral- or central-located small cell lung cancer: its clinical significance

BACKGROUND

Small cell lung cancer (SCLC) has a higher percentage of hilar masses than other histological types of lung cancer. The primary site is usually adjacent to the hilum, but we often observe primary sites in the peripheral lung field. In this study, our objectives were to elucidate whether peripheral-located small cell lung cancer (PSCLC) is an independent entity and whether it differs clinically from central-located small cell lung cancer (CSCLC).

METHODS

We reviewed the clinical and pathological features of 52 patients treated at Kagawa Medical University Hospital between 1987 and 1996 with a diagnosis of SCLC. We defined CSCLC as a tumor whose primary site is located in the segmental bronchi or more proximally and PSCLC as a tumor located distal to the subsegmental bronchi. Twenty-one PSCLC patients and 31 CSCLC patients were identified. Kaplan-Meier survival curves were constructed and comparisons were made between PSCLC and CSCLC by the log-rank test. The carcinoembryonic antigen (CEA) level was also evaluated in each group.

RESULTS

Although the percentage of limited disease (LD) in the patients with PSCLC was higher than that in the patients with CSCLC, the 3-year survival rate of PSCLC tended to be worse than that of CSCLC (9% for patients with PSCLC and 29% for those with CSCLC). Survival curves of patients with PSCLC also tended to be worse than those of patients with CSCLC, not only in the limited disease group but also in the extensive disease (ED) group. In addition, the mean CEA value in patients with PSCLC was higher than that in patients with CSCLC (p < 0.001), whereas the neuron specific enolase (NSE) level was not significantly different between PSCLC and CSCLC. The median survival of patients with pretherapeutic CEA titers of > or =5 ng/ml was significantly shorter than that in patients with CEA levels <5 ng/ml.

CONCLUSION

These findings suggest that the survival of SCLC patients with a high CEA level was significantly shorter than that of patients with a low CEA level. In addition, CEA levels in PSCLC patients were significantly higher than those in CSCLC patients. However, the survivals of LD or ED patients with PSCLC and CSCLC were not statistically different.

Hand-assisted laparoscopic distal gastrectomy with regional lymph node dissection for gastric cancer

Recently, a minimally invasive operation for gastric malignancies has been advocated, and the laparoscopic operation is noted as a technique that raises the quality of life. We performed distal gastrectomy with regional lymph node dissection by hand-assisted laparoscopic surgery for 60 cases of gastric cancer located in the middle or lower third of the stomach. Billroth I reconstruction was applied intracorporeally to the first 30 cases by using the double stapling method with a conventional circular stapling device, and in the final 30 cases, the quadrilateral (square) stapling technique with a laparoscopic linear stapling device was used to prevent postoperative anastomotic bleeding. This technique not only is less invasive, but also is similarly curative compared with open gastrectomy that was performed for 60 gastric cancer cases of similar staging before the beginning of this procedure.

C-type natriuretic peptide induces redifferentiation of vascular smooth muscle cells with accelerated reendothelialization

We recently reported that C-type natriuretic peptide (CNP) occurs in vascular endothelial cells and acts as a vascular-type natriuretic peptide. In the present study, we stimulated the cGMP cascade in proliferating smooth muscle cells (SMCs), in which particulate guanylate cyclase-B, the specific receptor for CNP, is predominantly expressed, by use of an adenovirus encoding rat CNP cDNA (Ad.CNP). In the Ad.CNP-treated cultured SMCs, CNP caused the growth inhibition of SMCs at G(1) phase with an early increase of p21(CIP1/WAF1) expression and subsequent upregulation of p16(INK4a). The expression of smooth muscle myosin heavy chain-2, which is the molecular marker of highly differentiated SMCs, was reinduced in the Ad.CNP-treated SMCs. The Ad.CNP-treated SMCs also reexpressed particulate guanylate cyclase-A, which shows high affinity to atrial and brain natriuretic peptide and is exclusively expressed in well-differentiated SMCs. CNP, which was overexpressed in rabbit femoral arteries in vivo at the time of balloon injury, significantly suppressed neointimal formation. Furthermore, an enhancement of the expression of smooth muscle myosin heavy chain-2 occurred in the residual neointima. In addition, early regeneration of endothelial cells was observed in the Ad.CNP-infected group. Thus, stimulation of cGMP cascade in proliferating dedifferentiated SMCs can induce growth inhibition and redifferentiation of SMCs with accelerated reendothelialization.

A neonate with Löffler syndrome

We report a neonate-boy with pulmonary infiltrates and peripheral blood eosinophilia. He was noted to have abnormal pulmonary infiltrates on a chest X-ray film taken on day 8 after birth when he had vomiting. He had not such symptoms as cough or dyspnea. In routine laboratory studies, eosinophilia was noted. Radiographic changes were transient and disappeared by day 25. Eosinophilia was also transient and gradually returned to normal level by 2 months. Löffler syndrome is very rare in neonates and its diagnosis is often made fortuitously likely in this case.

Oxidized LDL regulates vascular endothelial growth factor expression in human macrophages and endothelial cells through activation of peroxisome proliferator-activated receptor-gamma

Vascular endothelial growth factor (VEGF) has been recognized as an angiogenic factor that induces endothelial proliferation and vascular permeability. Recent studies have also suggested that VEGF can promote macrophage migration, which is critical for atherosclerosis. We have reported that VEGF is remarkably expressed in activated macrophages, endothelial cells, and smooth muscle cells within human coronary atherosclerotic lesions, and we have proposed the significance of VEGF in the progression of atherosclerosis. To clarify the mechanism of VEGF expression in atherosclerotic lesions, we examined the regulation of VEGF expression by oxidized low density lipoprotein (Ox-LDL), which is abundant in atherosclerotic arterial walls. A recent report has revealed that peroxisome proliferator-activated receptor-gamma (PPARgamma) is expressed not only in adipocytes but also in monocytes/macrophages and has suggested that PPARgamma may have a role in the differentiation of monocytes/macrophages. Furthermore, 9- and 13-hydroxy-(S)-10,12-octadecadienoic acid (9- and 13-HODE, respectively), the components of Ox-LDL, may be PPARgamma ligands. Therefore, we investigated the involvement of PPARgamma in the regulation of VEGF by Ox-LDL. PPARgamma expression was detected in human monocyte/macrophage cell lines, human acute monocytic leukemia (THP-1) cells, and human coronary artery endothelial cells (HCAECs). Ox-LDL (10 to 50 microg/mL) upregulated VEGF secretion from THP-1 dose-dependently. VEGF mRNA expression in HCAECs was also upregulated by Ox-LDL. The mRNA expression of VEGF in THP-1 cells and HCAECs was also augmented by PPARgamma activators, troglitazone (TRO), and 15-deoxy-(12,14)-prostaglandin J(2) (PGJ2). In contrast, VEGF expression in another monocyte/macrophage cell line, human histiocytic lymphoma cells (U937), which lacks PPARgamma expression, was not augmented by TRO or PGJ2. We established the U937 cell line, which permanently expresses PPARgamma (U937T). TRO and Ox-LDL augmented VEGF expression in U937T. In addition, VEGF production by THP-1 cells was significantly increased by exposure to 9-HODE and 13-HODE. In conclusion, Ox-LDL upregulates VEGF expression in macrophages and endothelial cells, at least in part, through the activation of PPARgamma.

[Trial manufacture of a plunger to reduce finger exposure]

According to the results of to a survey conducted by the Japanese Society of Nuclear Medicine Technology in 1995, the mean monthly exposure dose to the trunk of nuclear medicine technicians was less than 0.2 mSv at more than 75% of the institutions, whereas the exposure dose to the fingers exceeded 0.5 mSv at 30% of the institutions. Many recent radiopharmaceuticals are being supplied as the syringe type, and while the syringe is surrounded by a tungsten or lead-glass shield, there is no shielding of the syringe needle or the plungers. The plastic plunger provides little shielding effect, and even when a tungsten plunger is used, calculating back from the leakage rate, the shielding effect for 99mTc is approximately 75%. We therefore trial-manufactured a plunger devised in such a manner as to considerably reduce exposure of the fingers and evaluated its shielding effect from leakage rate obtained with a dual-detector scintillation camera when the radionuclides 99mTc, 67Ga, 201Tl, and 123I were used. Its performance was satisfactory, with shielding effects (99mTc, 99%; 67Ga, 95%, 201Tl, 95%; 123I, 73%) about the same or better than back-calculated from the leakage rates.