In vivo radiosensitizing effect of nitroimidazole derivative KIN-804

PURPOSE

In vivo characteristics of 2-nitroimidazole-1-methylacetohydroxamate (KIN-804), which is a newly developed hypoxic cell radiosensitizer, are presented.

METHODS AND MATERIALS

The toxicity, pharmacokinetics, and radiosensitizing effect of KIN-804 were studied by in vivo experiments using C3H/He mice bearing the SCC-VII tumor. Results were compared with misonidazole (MISO).

RESULTS

LD50(7) of KIN-804 and MISO were 3200 mg/kg and 2000 mg/kg, respectively. The peak of concentrations of KIN-804 in the tumor occurred 20 min after intraperitoneal injection and reached about 62% of the maximum concentration in the blood. The concentrations in brain and sciatic nerve were very low and clearance from sciatic nerve was rapid. Enhancement ratios of KIN-804 calculated using the growth delay method were 1.22, 1.50 and 1.71 at doses of 50, 100, and 200 mg/kg, respectively, compared with 1.36 for MISO at a dose of 100 mg/kg. In the TCD50 assay, enhancement ratios at a dose of 200 mg/kg were 1.69 for KIN-804 and 1.52 for MISO, respectively.

CONCLUSION

KIN-804 is a promising radiosensitizer since it shows less toxicity and higher radiosensitizing activity than MISO.

Serotonin depletion by p-chlorophenylalanine decreases VIP mRNA in the suprachiasmatic nucleus

The influence of serotonergic inputs on the levels of vasoactive intestinal peptide (VIP) mRNA in the rat suprachiasmatic nucleus (SCN) was examined by in situ hybridization combined with morphometrical analysis. Depletion of serotonin by p-chlorophenylalanine methyl ester (300 mg/kg i.p. daily for 3 days) caused a marked decrease in VIP mRNA signal levels in the ventrolateral part of the SCN. This finding suggests that serotonergic input controls VIP production at the mRNA level.

Malignant melanoma within an intradermal nevus

We describe a case of malignant "dermal" melanoma that arose within a preexisting intradermal nevus. Clinically, the lesion had recently enlarged. Histologically, two patterns were noted. One was an intradermal nevus in the upper portion of the dermis; the other was a deeper nodule composed of malignant neoplastic cells that extended into the reticular dermis. No melanocytic epidermal junctional activity was noted. Despite careful clinical investigation, no alternative primary source was found. Neoplastic transformation of the intradermal nevus without junctional activity is our proposed interpretation of the lesion's histology. Immunohistochemical stains demonstrated that the deeper dermal neoplastic cells were positive for both HMB-45 and PCNA, whereas the superficial nevoid-appearing cells were negative; these findings support our postulate that this melanoma arose within an intradermal nevus. It is important to distinguish this neoplasm from other diagnostic possibilities, including a metastatic lesion originating from another site.

Autoradiographic distribution of [3H]YM-09151-2, a high-affinity and selective antagonist ligand for the dopamine D2 receptor group, in the rat brain and spinal cord

We determined the regional distribution of the dopamine D2 receptor group in the rat central nervous system by quantitative receptor autoradiography with a high-affinity and selective antagonist, [3H]YM-09151-2. Saturation and competition experiments demonstrated that the binding of [3H]YM-09151-2 to striatal sections was saturable (Bmax = 37.3 fmol/section), of high affinity (Kd = 0.315 nM), and was inhibited selectively by prototypic D2 ligands. The anatomical localization of binding sites was determined by comparison of autoradiograms and the original 3H-ligand-exposed sections stained with cresyl violet. Very high levels of [3H]YM-09151-2 binding were found in the caudate-putamen, nucleus accumbens, tuberculum olfactorium and the insula of Calleja, to each of which midbrain dopaminergic neurons project densely. High levels of binding were also observed in other regions rich in dopaminergic neurons and fibers including the glomerular layer of the olfactory bulb, the intermediate lobe of the pituitary, lateral septum, substantia nigra pars compacta, interfascicular nucleus, dorsal raphe nucleus, locus coeruleus, and nucleus of the solitary tract. Some regions poor in dopaminergic innervation, however, had high levels of [3H]YM-09151-2 binding including the molecular layer of gyrus dentatus, all layers of CA1 and the nonpyramidal layer of CA4 of hippocampus, and the deeper layer of medial entorhinal cortex. Motor neurons present in brainstem motor nuclei and spinal ventral horn were also strongly labeled. Neocortical, cerebellar, and thalamic regions had low levels of binding, except lobules 9-10 of the cerebellum, the olivary pretectal nucleus, zona incerta and lateral mammillary nucleus, in which moderate to high levels of binding were detected. Our findings concerning the widespread but region-specific localization of [3H]YM-09151-2 binding sites in the brain and spinal cord may prove useful for analyzing various dopaminergic functions in the central nervous system.

Better grading systems for evaluating the degree of lymph node invasion in cancer of the thoracic esophagus

To evaluate the quality of various grading systems for lymph node invasion in cancer of the thoracic esophagus, the surgical results of 142 patients who underwent systematic lymph node dissection with curative intent were analyzed. The survival probability of patients in the same grade was modeled using a Weibull distribution and the parameters were estimated by the maximum likelihood principle. The quality of each grading system was measured by the Akaike Information Criterion (AIC) of the estimated statistical model, by which the smaller the AIC of a grading system, the smaller the loss of information for predicting outcomes. The AIC of the TNM grading of the International Union Against Cancer, the grading of the Japanese Society for Esophageal Diseases, and the grading designed according to the total number of positive lymph nodes became substantially smaller in that order. The AIC of grading systems variously designed on rather simple criteria were examined with the aim of creating a better grading system. It was concluded that a grading system based on the total number of positive nodes and the state of the paratracheal and/or middle mediastinal node groups was better than the other systems examined.

[A study of bone mineral density in postmenopausal and senile osteoporosis with vertebral fractures in female]

Bone mineral density of the lumbar vertebrae (L2-4BMD) in involutional osteoporosis was measured by dual photon absorptiometry to investigate its relationship with the incidence of osteoporotic vertebral fractures of the thoracic and lumbar spine. In addition to monitor L2-4BMD, the author also examined the progress of vertebral fractures during drug treatments by means of radiographs. L2-4BMD at the antero-posterior projection was measured in 287 female subjects with involutional osteoporosis ranging from 45 to 91 years of age. Fracture of the vertebrae was determined from lateral radiographs. Low BMD is the most important risk factor in vertebrae fractures. There was a significant difference in L2-4BMD with and without fractures of the vertebrae. L2-4BMD for threshold was 0.633 g/cm2 for 90th percentile with vertebral fractures, and that for breakpoint was 0.532 g/cm2 for 65th percentile with vertebral fractures. The incidence of vertebral fractures with BMD above the threshold was 17.5%, however that between the threshold and the breakpoint was 30.6%. Furthermore that below the breakpoint was 48.9%. Although the incidence of vertebral fractures was affected to some extent by age, height, and weight, the number of vertebral fractures increased with the decrease of L2-4BMD. The progress of vertebral fractures under drug treatments with 1,25-dihydroxyvitamin D3, ipriflavone, and calcitonin was affected by pre-existing vertebral fractures and L2-4BMD at the first visit. Estimation of L2-4BMD and the existence of vertebral fractures is important in predicting new vertebral fractures and the further collapse of pre-existing vertebral fractures.

[The diagnosis of a mutation of the insulin receptor by non-radioisotropical RT-PCR-SSCP analysis]

We evaluated a 24 years old diabetes woman with type A insulin resistant (patient "Yakushima") who had some typical symptoms as acanthosis nigricans, hirsutism and virilization. Insulin binding to the patient's erythrocytes was significantly decreased to about 30% of the normal control. In order to determine the mutation of the insulin receptor, we used for reverse transcript-polymerase chain reaction-single strand conformation polymorphism (RT-PCR-SSCP) analysis without using radiolabeled materials. We also analysed the nucleotide sequence with non-isotropical probe. Our results suggested that the mutation was heterozygous, and the patient had a new missense mutation substituted Asn461 for Thr461 in the alpha-subunit.

Serum pepsinogen as a new marker for gastric carcinoma among young adults. Research Group on Prevention of Gastric Carcinoma among Young Adults

BACKGROUND

Gastric carcinoma is relatively uncommon in Japan among persons younger than 40 years of age, but its prognosis is not favorable and it affects young adults in their most productive years. This study was performed to evaluate the validity of serum pepsinogen as a new marker for gastric carcinoma among Japanese younger than 40 years of age.

METHODS

Data and sera were collected from the patients (108 patients younger than 40 years of age with gastric carcinoma from nine hospitals in the Kanto-Shin'etsu area in Japan) and from the control subjects (108 hospital control subjects and 108 screening control subjects) whose sex and age (within 4 years) were matched. Pepsinogen I and pepsinogen II values were measured and compared between patients and control subjects by paired t test. Sensitivities and specificities when criteria were defined by pepsinogen I, pepsinogen II, and pepsinogen I/II ratio were calculated.

RESULTS

The pepsinogen I and pepsinogen II levels among patients were higher and the pepsinogen I/II ratio among patients was lower than among control subjects. When a pepsinogen II level higher than 14.8 ng/ml was considered positive, the test showed high sensitivity (83.3% for total gastric carcinoma and 85.0% for early gastric carcinoma) and high specificity (76.9% for hospital control subjects and 75.0% for screening control subjects). Similar degrees of sensitivity and specificity were obtained with the pepsinogen I/II ratio.

CONCLUSIONS

These results suggest that a high pepsinogen II level combined with a low pepsinogen I/II ratio may be a useful screening test for gastric carcinoma in a young population at high risk for gastric carcinoma. This impression should be confirmed by a more extensive field trial to determine whether performance of these assays promotes early diagnosis of gastric carcinoma.

Cortical control of saccade in normal and schizophrenic subjects: a PET study using a task-evoked rCBF paradigm

In this study, positron emission tomography (PET) was used to evaluate cortical control of saccades. Regional cerebral blood flow (rCBF) patterns demonstrated by 15O water PET during saccadic task performance were tested in 13 normal volunteers and 20 ICD-9 schizo phrenics (10 unmedicated and 10 medicated). The following 3 saccadic tasks, which were controlled for sensory input and oculomotor output, were applied: (1) reflexive saccade = visually guided saccade, (2) volitional saccade = visually guided saccade with distracting stimuli, and (3) memory guided saccade. Schizophrenics lacked the frontal eye field (FEF) activation during every saccadic task. The left dorsolateral prefrontal cortex (DLPFC) was activated during volitional saccade only in normal controls. The rCBF of posterior parietal cortex increased in parallel with that in the DLPFC. These findings suggest functional hypofrontality in schizophrenia and the left DLPFC-PPC's crucial role in saccade against distracting stimuli and its dysfunction in the disease.

Effects of oxygen free radical scavengers on uranium-induced acute renal failure in rats

Study was made to determine whether oxygen free radicals mediate uranium-induced acute renal failure (ARF). Superoxide dismutase (SOD), a superoxide anion scavenger, did not prevent uranium acetate (UA) (5 mg/kg, i.v.)-induced renal injury 48 h after injection. In contrast, dimethylthiourea (DMTU), a hydroxyl radical scavenger, significantly attenuated UA-induced rise in serum creatinine concentration (1.11 +/- 0.05 (DMTU) vs. 1.40 +/- 0.06 mg/dl (control), p < .05), and tubular necrosis. Dimethyl sulfoxide (DMSO), a hydroxyl radical scavenger, decreased UA-induced tubular damage. UA injection caused no increase in renal cortical malondialdehyde (MDA) content. DMTU and DMSO did not modify intrarenal MDA content. UA administration brought about significant increase in plasma renin activity but not in renal cortical renin content. Treatment with DMTU and DMSO had no effect on plasma renin activity or intrarenal renin content. It follows from these findings that DMTU and DMSO may attenuate UA-induced renal injury. Such a protective effect would not be mediated through modulation of lipid peroxidation or renin activity.

[Effects of estrogen and progestin on platelet-activating factor acetylhydrolase]

Platelet-activating factor (PAF) is one of the potent proinflammatory agents and is associated with a number of human diseases, including asthma, endotoxin shock and cardiovascular diseases. Additionally, plasma PAF acetylhydrolase (PAF-AH) activity to inactivate PAF is regulated by hormones. In this study, we elucidated the effects of estrogen and progestin on plasma PAF-AH and also the effects of PAF on rat tissues to investigate the mechanisms involved in the thrombotic episode. Plasma PAF-AH activity in female adult rats treated with 17 alpha-ethynylestradiol (50 micrograms/kg, 5 days) was decreased by 50%. However, medroxyprogesterone (50 mg/kg, 5 days) increased the enzyme activity by 50%. When PAF (5 to 60 nmol/kg) was injected intravenously into non-treated female adult rats, 80% of the animals died at 20 nmol/kg of PAF. Macroscopic findings showed hemorrhage, hyperemia and congestion in the lungs and heart, and necrosis-like change in the gastrointestines. Microscopically, thrombus was observed in the lungs and heart. When PAF was administered to female adult rats pretreated with sex steroid hormones, the mortality of the rats with low plasma PAF-AH activity caused by estrogen was increased, but decreased in the animals with high enzyme activity caused by progestin. These findings suggest that the imbalance between PAF and plasma PAF-AH is one of the mechanisms involved in the thrombotic episode, and estrogen and progestin are related to the event by regulating the plasma PAF-AH activity.

A 3-Mb physical map of the chromosome region 8p21.3-p22, including a 600-kb region commonly deleted in human hepatocellular carcinoma, colorectal cancer, and non-small cell lung cancer

To isolate a putative tumor suppressor gene(s), we have constructed a physical map and a detailed deletion map of chromosome region 8p21.3-p22, where loss of heterozygosity (LOH) has been frequently seen in human hepatocellular carcinomas (HCC), colorectal cancers (CRC), and non-small cell lung cancers (NSCLC). The smallest commonly deleted region at 8p21.3-p22 in HCC and CRC was between the loci defined by C18-245 and C18-2644; in NSCLC, a region between C18-1051 and C18-2644 was commonly deleted. A contiguous physical map of 12 cosmid markers in the 8p21.3-p22 region was constructed by means of multi-color fluorescence in situ hybridization (FISH) and pulsed-field gel electrophoresis (PFGE). On the basis of this physical map, which spans roughly 3.1 Mb, the estimated sizes of the commonly deleted regions were at most 1.2 Mb in HCC and CRC and 0.6 Mb in NSCLC. As four of the 12 physically ordered markers are located within the 0.6 Mb region commonly deleted in all three tumor types, nearly one fourth to one fifth of the target region has already been covered with cosmid inserts.

Rod-like intracytoplasmic inclusions in large neurons of the caudate nucleus: frequent appearance in myotonic dystrophy

Brain autopsy materials from 5 patients diagnosed clinicopathologically as having myotonic dystrophy (MyD) were studied. All of the cases showed many rod-like intracytoplasmic inclusions, which have never been reported in the disease, in the large neurons of the caudate nucleus. The rod-like inclusions were observed in the cytoplasm near the nucleus, and showed eosinophilic staining with HE, blue with PTAH, red with Masson's trichrome, and blue with toluidine blue. Electron microscopically, the inclusions had an internal structure composed of parallel beaded dark filaments and clear spaces. In transverse section, the inclusions showed tetragonal arrays of filaments. These histological characteristics of the inclusions were similar to those of inclusions reported previously in the same location in various disorders, showing increasing incidence with aging. Quantitative investigation on the 5 patients and 24 control subjects revealed that the number of neurons containing the inclusion in the caudate nucleus of MyD patients was about twice as many as the control subjects, and that the occurrence rate of the inclusion body to the large neurons in the caudate nucleus in MyD was far higher than that of the controls. The finding indicates that the inclusion body is important for the diagnosis of the disease, and may have a close relationship with the neurological symptoms and pathogenesis of the disease.

[Distribution and frequency of gastric cancer at the para-cardiac region and fornix]

To clarify the distribution and frequency of gastric cancer in the upper third of the stomach, especially in the para-cardiac region and fornix, we reviewed 634 lesions of all gastric cancers in any location in the University Hospital of Tsukuba University from April 1985 to March 1992. The para-cardiac region was defined as a circular area of 6 cm in diameter around the cardia. We found 56 lesions (8.8%) in the para-cardiac region, almost all of which were concentrated in the distal half of the para-cardiac region, and only three of which (0.47%) were in the fornix. Cancer in the upper third of the stomach tended to occur predominantly in aged male patients, and histologically most of them were classified as having differentiated adenocarcinoma. Since the percentage of advanced cancer at the para-cardiac region was much higher than at any other location, we should be careful to obtain double-contrast images of sufficient quality during the upper gastrointestinal examinations and not to overlook subtle changes in this region during the interpretation of films.

Glutamate release in the gerbil hippocampus after middle cerebral artery occlusion

In a modified version of the unilateral middle cerebral artery occlusion (MCAO) model in gerbils, both sides of hippocampus are spared from direct ischaemic insult. Using this newly employed left MCAO model in gerbils, we investigated the concentrations of extracellular amino acids in the left hippocampus by microdialysis and histological changes in both sides of hippocampus one month after ischaemia. The concentrations of glutamate and aspartate were significantly increased by more than 3.5 times basal levels after MCAO. Glutamate maintained this peak level for 40 to 120 min after the onset of ischaemia. However, hippocampal neurones were well preserved one month after MCAO. While the exact mechanism of the survival of hippocampal neurones remains to be elucidated, we suggest it may be crucial that the hippocampus be protected from ischaemic insult.

Molecular mechanism of cibenzoline-induced anticholinergic action in single atrial myocytes: comparison with effect of disopyramide

The anticholinergic effects of cibenzoline were examined and compared with those of disopyramide in atrial myocytes isolated from guinea pig heart. The tight-seal whole-cell voltage clamp technique was performed with a patch pipette filled with guanosine-5'-triphosphate (GTP) or guanosine-5'-O-(3-thiotriphosphate) (GTP gamma S). In GTP-loaded cells, both acetylcholine (ACh) and adenosine (Ado) induced a specific K channel current through GTP-binding proteins by binding to the muscarinic and Ado receptors, respectively. Both cibenzoline and disopyramide suppressed the ACh-induced K current effectively in a concentration-dependent manner. The concentrations for half-maximal inhibition of the current (EC50) caused by cibenzoline and disopyramide were 8 and 3 microM, respectively. In GTP gamma S-loaded cells, the K current was irreversibly activated because GTP binding proteins were directly elicited by GTP gamma S. Cibenzoline effectively caused a decrease in the GTP gamma S-induced K current, whereas the extent of disopyramide action on the GTP gamma S-induced K current was much less. Cibenzoline also caused significant inhibition of Ado-induced K current in GTP-loaded cells. However, the action of disopyramide was less effective in inhibiting Ado-induced K current. These results indicate that cibenzoline has less potent anticholinergic effects than disopyramide in atrial myocytes. In addition, cibenzoline effectively inhibits the muscarinic K channel itself and/or GTP-binding proteins coupled to the channel, whereas the effect of disopyramide is attributed mainly to blockade of muscarinic receptors. These findings provide novel understanding of the molecular mechanism of anticholinergic action of cibenzoline.

The recognition of cancer-associated fucosylated antigens in colorectal cancer by a novel monoclonal antibody, YB-2

A monoclonal antibody, YB-2, which has a novel epitope for fucosylated antigens and shows cross-reactivity with Y/Leb/H type 2 antigens, was used in an immunohistochemical study of human neoplastic and normal colorectal tissues. Of 64 colorectal cancers, 59 (92.2%) were stained by the YB-2 antibody; however, only 3 (12.0%) of 25 samples of normal colon mucosa and 13 (50.0%) of 26 adenomas expressed the antigens recognized by YB-2. Clinicopathologically, the YB-2-negative colon cancers were exclusively in Dukes stage A. These results indicate that the monoclonal antibody, YB-2, could detect cancer-associated antigens, and the degree of YB-2-reacted antigen expression might be correlated with the progression of colorectal carcinogenesis.

[A case of mediastinal neurilemmoma originating from the intrathoracic vagal nerve]

A case of neurilemmoma originating from the intrathoracic vagal nerve was reported. An asymptomatic 51-year-old man was admitted because of a mass shadow on chest roentgenograms. Under the possible diagnosis of benign bronchogenic cyst, right thoracotomy was carried out. An encapsulated solid tumor originating from the right vagal nerve was found in the site distal to the branching point of recurrent nerve. The tumor was removed by transection of the vagal nerve. Postoperative clinical course was uneventful except the transient sinus tachycardia. The pathological diagnosis was neurilemmoma. Mediastinal neurilemmoma originating from the vagal nerve is rare. To our knowledge, only 29 cases are reported in the Japanese literatures.

Evaluation of malignant grade of salivary gland tumors: studies by cytofluorometric nuclear DNA analysis, histochemistry for nucleolar organizer regions and immunohistochemistry for p53

Investigations were carried out in 109 surgically resected salivary gland tumors, 46 adenomas and 63 carcinomas for nuclear DNA content by cytofluorometry, nucleolar organizer regions (AgNOR) by histochemistry and nuclear p53 accumulation by immunohistochemistry. The mean nuclear DNA content and the incidence of aneuploidy as well as the mean number of the AgNOR in carcinomas were significantly higher than those in adenomas. In the DNA histogram pattern, the aneuploidy frequently appeared in high grade carcinoma groups (adenocarcinoma, salivary duct carcinoma, carcinoma in pleomorphic adenoma and oncocytic carcinoma). Immunohistochemical nuclear p53 accumulation was observed in 15 tumors, of which ten showed DNA aneuploidy. In high grade carcinomas, DNA aneuploidy was closely related to p53 immunoreactivity. This study revealed that combined cytofluorometric nuclear DNA analysis, histochemical AgNOR count and immunoreactivity for p53 might be quite useful for evaluating the malignant grade of salivary gland tumors.

Nephrogenic diabetes insipidus associated with bilateral ureteral obstruction

Nephrogenic diabetes insipidus associated with ureteral obstruction is rare. We report a case of nephrogenic diabetes insipidus associated with ureteral obstruction caused by ileal leiomyosarcoma in a 32-year-old man. The treatment with trichlorothiazide and diclofenac sodium reduced urine output from 8 L/day to 4 L/day. Six months after nephrostomy, urine output decreased to 2.5 L/day without any drug administration. This case suggests that ureteral obstruction may cause an increase in urine output to 8 L/day and that surgical treatment for ureteral obstruction is effective in reducing urine output in nephrogenic diabetes insipidus patients with ureteral obstruction.

[Suppressive effect of oxatomide on the induction of IL2 responsiveness by DF-stimulated lymphocytes from patients with bronchial asthma]

Oxatomide is an anti-allergic agent having an anti-histamine effect, and has been widely used for clinical purposes. The effect of oxatomide-treatment on the induction of IL2 responsiveness by Df-stimulated lymphocytes was studied in patients with bronchial asthma. Oxatomide alone has almost no effect on lymphocyte activation. Patient's lymphocytes pretreated with 2 to 2000 ng/ml doses of oxatomides for 24 to 48 hours failed to produce Df-induced IL2 responsiveness in a dose-dependent manner. The target cells for oxatomide's suppressive effect were antigen-presenting cells such as macrophages and dendritic cells rather than responder T cells. PPD-induced IL2 responsiveness was also suppressed by the treatment, but the Con A-induced response was not. The results suggest that oxatomide has a slight immunosuppressive capability to block the induction of IL2 responsiveness by Df-stimulated patient's lymphocytes, resulting in the decreased production of such lymphokines as IL2, IL3, IL4, IL5, in a lymphokine cascade of allergic responses, in addition to inhibition of the degranulation and activation of inflammatory cells such as mast cells/basophils and eosinophils.

Expression of proliferating cell nuclear antigen in invasive ductal carcinoma of the breast

Formalin-fixed, paraffin-embedded sections from 92 breast cancers (invasive ductal carcinomas) were immunostained with a monoclonal antibody against proliferating cell nuclear antigen (PCNA). The labeling index of PCNA ranged widely from 2 to 76 (mean 24.8)%. The labeling index was classified into three groups: low (< 25%), intermediate (25-50%), high proliferation (> 50%). Younger patients seemed to have a higher labeling index than older ones. The labeling index for tumors < or = 2 cm was lower than that of tumors larger than 2 cm. The labeling index in patients with high estrogen receptor (ER) levels (> 100 fmol/mg cytosol protein) was significantly lower than that in patients with low ER levels (< 10 fmol/mg cytosol protein). In relation to histological type, the labeling index of scirrhous carcinoma was significantly lower than that of papillotubular carcinoma or solid-tubular carcinoma. The high proliferating group had a significantly worse overall survival rate than the low proliferating group. Labeling index was shown to be a possible prognostic indicator.

How extensive should lymph node dissection be for cancer of the thoracic esophagus?

From 1985 to 1992, 171 patients with cancer of the thoracic esophagus underwent esophagectomy with systematic dissection of regional lymph nodes including cervical nodes. The hospital mortality rate was 5.3%. The dissected nodes were classified into four groups: the deep cervical (C), upper mediastinal and cervical paratracheal (U), middle and lower mediastinal (L), and upper perigastric (G) groups. The U group mainly consisted of nodes beside the recurrent laryngeal nerves. The phase of cancer infiltration of lymph nodes was evaluated by the total number and the distribution of involved nodes. Of cases with nodal involvement, only 37% were in the late phase, in which more than seven nodes or in which the U, L, and G groups were all involved. Of cases in the earliest phase in which only one node was involved, 93% had either the U or G group involved. The C group of nodes was infrequently involved until the late phase. Cancer had metastasized to the U and G groups across a considerable anatomic distance even in earlier phases. Outcomes of the cases with nodal involvement not in the late phase were satisfactory; the cumulative survival was 60% at 3 years and 54% at 5 years. Systematic nodal dissection would benefit even cases with nodal involvement, unless the disease is in the late phase. Nodes beside the recurrent nerves and upper perigastric nodes should be dissected with higher priority, though they are located anatomically distant.