Vincristine saturation of cellular binding sites and its cytotoxic activity in human lymphoblastic leukemia cells: mechanism of inoculum effect

Vincristine (VCR) is an active agent in the treatment of acute lymphoblastic leukemia (ALL). We evaluated the relationship between the cytotoxic activity of VCR and the degree of VCR saturation of cellular drug binding sites, using the MOLT-3 ALL cell line. When MOLT-3 cells at a density of 1 x 10(6) or 1 x 10(8) cells/mL of pH-controlled medium were exposed to VCR for 1 hr, its cytotoxic activity on cells at high density was 10-fold less than on cells at low density (inoculum effect). The number of VCR binding sites measured by Scatchard analysis was 9.25 x 10(6)/cell. At high cell density, the saturation of VCR binding sites was one log order less than that at low density. Irrespective of cell density, curves of cell-kill versus the degree of VCR saturation of the cellular binding sites overlapped each other. Minimal cytotoxic activity was observed at 0.3% VCR saturation, and nearly maximal cytotoxic activity occurred at about 25% saturation, with the Ic50 at about 4% saturation. These data show that the VCR-induced cell-kill effect is dependent on the degree of saturation of VCR binding sites rather than on the extracellular VCR concentration. The lesser cell-kill on cells at high density can be explained by the lack of drug molecules to sufficiently saturate cellular binding sites. This phenomenon may be responsible, at least in part, for the poor chemotherapeutic outcome of ALL patients with high leukocyte counts at presentation.

Alterations in serum levels of 1 alpha,25(OH)2 D3 and osteocalcin in patients with early diabetic nephropathy

Serum levels of markers for bone remodeling and diabetic metabolic markers were measured in subjects with non-insulin-dependent diabetes mellitus (NIDDM) to investigate the relationship between early diabetic nephropathy and calcium/bone metabolism. 1 alpha,25(OH)2 D3 (Vit D), osteocalcin (OC), intact parathyroid hormone (PTH) and urine albumin excretion (UAE) were measured in all subjects. Serum levels of Vit D and OC were significantly decreased in diabetic subjects compared to age-matched, non-diabetic controls. In diabetic patients, a significant positive correlation was observed between intact PTH and OC. No significant correlation was found between levels of Vit D and OC. In early diabetic nephropathy without increased serum creatinine, Vit D decreased and OC increased with increasing UAE. Levels of hemoglobin Alc (HbAlc) and fructosamine (FRA) were not correlated with levels of Vit D or OC. Levels of Vit D were decreased and levels of OC were increased in diabetic subjects with proliferative retinopathy or with micro- or macro-albuminuria.

CONCLUSIONS

Results of the present study indicate that changes in bone remodeling markers such as Vit D and OC levels are present in the early stages of diabetic nephropathy, and that circulating intact PTH is important in restoring the reduced OC levels in diabetic patients, probably as a reflection of bone remodeling.

Noonan syndrome presenting growth hormone neurosecretory dysfunction

Noonan syndrome has been diagnosed by the characteristic physical stigmata for more than two decades. Recent studies of growth hormone secretory pattern provide a new category of growth hormone neurosecretory dysfunction to characterize short stature. We describe herein a case of growth hormone neurosecretory dysfunction in a 16-year-old boy with Noonan syndrome. Growth hormone neurosecretory dysfunction was diagnosed primarily based on the low amplitude and small numbers of the spontaneous bursts of growth hormone secretion during 12-hour nocturnal growth hormone sampling. Treatment with synthetic human growth hormone has markedly accelerated the growth velocity for one year and a half. This case notes the wide spectrum of short stature in Noonan syndrome and the effectiveness of treatment with human growth hormone.

The influence of tumor cell density on cellular accumulation of doxorubicin or cisplatin in vitro

The effect of tumor cell density on the cellular pharmacokinetics of doxorubicin (DXR) and cisplatin (CDDP) was studied using MOLT-3 human acute lymphoblastic leukemia cells. As determined by the MTT assay, the growth-inhibitory effect of DXR was approx. 40 times lower when cell density was increased from 10(6) to 10(8) cells/ml (positive inoculum effect), whereas little or no influence of cell density was observed in CDDP-induced cell-growth inhibition. As measured by high-performance liquid chromatography using a fluorescence detector, the cellular accumulation of DXR showed 6- and 18-fold decreases after 1 h incubation when the cells were concentrated from 10(6) to 10(7) and 10(8) cells/ml, respectively. Only at low cell density (10(6) cells/ml) did the amount of DXR in the cells increase with increasing exposure times of up to 6 h. The DXR concentration in the supernatant that was separated from a cell suspension showing a density of 10(8) cells/ml fell to 20% of that obtained at 10(6) cells/ml. The metabolites of DXR, including Adriamycinol and Adriamycinone, were not detectable in the cell extracts or supernatants at any cell density examined. In contrast, the cellular accumulation of CDDP calculated from the platinum concentration, which was measured with a flameless atomic absorption spectrophotometer, was essentially identical at all cell densities examined; moreover, extension of the exposure period resulted in a linear increase in the amount of CDDP in the cells. CDDP concentrations in the supernatants were equally retained, irrespective of cell densities. These observations indicate that the positive inoculum effect shown in DXR-induced cell-growth inhibition results from the decreased cellular accumulation of the drug at high cell densities. We found no influence for cell density on the cellular accumulation of CDDP that might be relevant to the therapeutic potentiation of this drug at high tumor-cell density.

Antitumor activities of new platinum compounds, DWA2114R, NK121 and 254-S, against human leukemia cells sensitive or resistant to cisplatin

(R)-(-)-1,1-(2-amino-methylpyrrorodine)-platinum(II) (DWA2114R), cis-1,1-cyclobutanedicarboxylato(2R)-2-methyl-1,4-butanediammin eplatinum(II) (NK121; CI-973) and glycolate-o,-o'-diammine platinum(II) (254-S; NSC375101D) are new platinum compounds developed in Japan. We studied the antitumor effects of these compounds on the cisplatin (cis-diamminedichloroplatinum, DDP)-resistant human leukemia cell line, K562/DDP. K562/DDP cells were 10-fold resistant to DDP, while the cells showed minimal cross-resistance to carboplatin (2.1-fold) and DWA2114R (3.3-fold), and were as sensitive to NK121 (1.6-fold) and 254-S (1.0-fold) as the parent cells. Increases in exposure time of K562 cells to DWA2114R resulted in progressive shifting of the dose-response curve to the left, or more effective cell growth inhibition of the cells. Time dependency indices (ID80 obtained from dose-response curve after 1 hr-exposure of K562 cells to drug followed by 72 hr-culture without drug/ID80 after 24 hr-exposure) of DDP, NK121 and 254-S were 10, 8 and 20, respectively. A multidrug resistant cell-line, MOLT-3/TMQ200, was as sensitive to platinum compounds as the parent MOLT-3 cells. Little or no influence of tumor cell density was observed in the growth inhibition of MOLT-3 or K562 cells induced by these new compounds even if cells were concentrated to a density of 10(8) cells/ml. These results indicate that NK121 and 254-S may overcome the drug resistance developed in the patients after treatment with DDP. The antitumor effect of DWA2114R is more dependent not only on drug-concentration but also on exposure time than that of DDP, suggesting that continuous infusion rather than bolus administration appears the favorable schedule in clinical trials.

Evaluation of skin vasomotor reflexes in response to deep inspiration in diabetic patients by laser Doppler flowmetry. A new approach to the diagnosis of diabetic peripheral autonomic neuropathy

OBJECTIVE

To evaluate the peripheral sympathetic function in feet of NIDDM patients by means of laser Doppler flowmetry.

RESEARCH DESIGN AND METHODS

After deep inspiration, we measured the vasoconstrictor response in the feet of 51 patients with NIDDM, as compared with those of 20 healthy control subjects, using laser Doppler flowmetry. Subjects whose skin temperature was < 32 degrees C were excluded from our study because a skin temperature of approximately 34 degrees C is the optimal temperature for the evaluation of skin vasomotor reflexes in response to a deep inspiration by laser Doppler flowmetry.

RESULTS

The vasoconstrictor response to deep inspiration in the big toe was significantly decreased in NIDDM patients compared with healthy subjects (26.8 +/- 2.0 vs. 48.3 +/- 18.5%, P < 0.0001). In NIDDM patients, the vasoconstrictor response was positively correlated with the duration of diabetes, the median motor and sensory nerve conduction velocities, the coefficient of variation of the R-R interval at rest, and the postural fall in systolic blood pressure. The vasoconstriction was inversely correlated with the vibratory perception threshold.

CONCLUSIONS

Vasomotor reflexes in the lower limbs were markedly impaired in NIDDM patients. The measurement of vasoconstrictor responses to deep inspiration by using laser Doppler flowmetry is a novel and useful method for detecting peripheral sympathetic failure in diabetic patients.

Relation between the serum level of C-peptide and risk factors for coronary heart disease and diabetic microangiopathy in patients with type-2 diabetes mellitus

Syndrome X is used to describe a constellation of factors that lead to coronary heart disease (CHD): hypertension, hyperinsulinemia, impaired glucose tolerance, and an abnormality in lipid metabolism. We investigated the relationship between serum levels of C-peptide immunoreactivity (CPR) and diabetic complications in 256 patients with type-2 diabetes mellitus. The serum level of CPR was measured by radioimmunoassay (RIA). Diabetic patients were divided into 3 groups according to the serum level of CPR as follows: low CPR (n = 19, <0.7 ng/ml), normal CPR (n = 174, 0.7 to 2.2 ng/ml) and high CPR (n = 63, >2.2 ng/ml). The body mass index (BMI) and the serum level of triglycerides were significantly higher in the high CPR group (P < 0.05, respectively) compared with normal CPR group. The prevalence of hypertension was significantly higher in the high CPR group than in the other 2 groups (low CPR: 16%, normal CPR: 28%, high CPR: 38%). The frequency of the number of patients receiving insulin therapy was greater in the low CPR group than in the other 2 groups, (low CPR: 58%, normal CPR: 15%, high CPR: 11%). The serum CPR level was significantly lower in patients with than without proliferative retinopathy or macroalbuminuria. Our conclusion is that the present data suggest that an increased serum level of CPR is associated with obesity, elevated serum triglycerides, and hypertension in patients with type-2 diabetes mellitus. A low CPR level leading to hyperglycemia is associated with the progression of diabetic microangiopathies, such as retinopathy and nephropathy.

Plasma interleukin-6 is associated with coagulation in poorly controlled patients with Type 2 diabetes

AIMS

We investigated the relationship between interleukin (IL)-6 and coagulation, i.e. whether changes in the plasma IL-6 are associated with those in coagulation markers (D dimer and fibrinogen) after glycaemic control with sulphonylurea or insulin in poorly controlled patients with Type 2 diabetes.

METHODS

We studied 42 patients with Type 2 diabetes, including 19 subsequently treated with sulphonylurea, 23 treated with insulin and 48 control subjects. All patients were in poor glycaemic control and were hospitalized for 3 weeks. At the beginning and end of treatment, we measured plasma concentrations of IL-6, fibrinogen, and D dimer.

RESULTS

Plasma concentrations of IL-6 and D dimer were significantly higher in diabetic patients than in controls (P<0.0001 for both). In all patients with diabetes, the plasma concentration of IL-6 decreased significantly (P<0.001) after treatment. Changes in the plasma IL-6 during hospitalization were positively correlated with those in plasma D dimer and fibrinogen (r=0.664, P<0.0001; r=0.472, P=0.0042, respectively). Treatment with sulphonylurea or insulin caused a similar fall in the plasma IL-6 concentration with a concomitant decrease in the BMI and an equal improvement in glycaemia.

CONCLUSIONS

In poorly controlled patients with Type 2 diabetes, plasma IL-6 concentrations were reduced significantly even by short-term metabolic control. As changes in the plasma concentrations of D dimer are related to plasma IL-6, plasma IL-6 may reflect a pro-coagulant as well as an inflammatory state in patients with Type 2 diabetes.

The antiproliferative effect of acridone alkaloids on several cancer cell lines

Fifteen acridone alkaloids were examined for their antiproliferative activity toward monolayers and suspension of several types of cancer and normal human cell lines. As a result, atalaphyllidine (9), 5-hydroxy-N-methylseverifoline (11), atalaphyllinine (12), and des-N-methylnoracronycine (13) showed potent antiproliferative activity against tumor cell lines, whereas they have weak cytotoxicity on normal human cell lines. The structure-activity relationship established from the results revealed that a secondary amine, hydroxyl groups at C-1 and C-5, and a prenyl group at C-2 played an important role for antiproliferative activities of the tetracyclic acridones.

Epidemiologic study of the relationship between schistosomiasis due to Schistosoma japonicum and liver cancer/cirrhosis

In Yamanashi Prefecture, one of the former areas in Japan endemic for Schistosoma japonicum, there have been no cases of schistosomiasis since 1978. We attempted to find out in this study whether there was still a chronic effect of schistosomiasis, e.g., liver cancer or liver cirrhosis present in this region. The subjects studied were the population in Yamanashi Prefecture from 1973 through 1992. We divided the population into residents in an area endemic for schistosomiasis and those in a nonendemic area. We calculated the standardized mortality ratios (SMRs) for liver cancer and liver cirrhosis in both areas. The schistosome egg-positive rate of liver cancer and liver cirrhosis specimens from the patients in these two endemic areas was also calculated. Male SMRs for liver cancer in the endemic area were 188.5% in 1985 and 188.0% in 1990. Even today, many years after the last case of schistosomiasis, schistosome eggs can be found in the livers of deceased liver cancer and cirrhosis patients. The chronic effect of S. japonicum could contribute to the current high mortality rate for liver cancer in the endemic area, although we need to consider the other etiologic factors of liver cancer, e.g., hepatitis B virus, hepatitis C virus, and alcohol intake.

Isolation and identification of two new flavanones and a chalcone from Citrus kinokuni

Two new flavanones and one chalcone were isolated from the peel of Citrus kinokuni Hort. ex Tanaka and identified as (2S)-5,6,7,8,4'-pentamethoxyflavanone (1), (2S)-5,6,7,3',4'-pentamethoxyflavanone (2) and 2'-hydroxy-3,4,3',4',6'-pentamethoxychalcone (3). The structures of new compounds were elucidated by spectroscopic analysis.

Hyperuricemia in patients with hyperthyroidism due to Graves' disease

The effects of hyperthyroidism on uric acid metabolism were investigated. First, the serum uric acid level was measured in 92 patients with hyperthyroidism due to Graves' disease, eight patients with subacute thyroiditis, six patients with hypothyroidism, and 70 sex- and age-matched controls. Second, the correlation between serum thyroxine (T4) and serum uric acid was obtained in hyperthyroid Graves' disease patients before and during antithyroid drug therapy. Finally, uric acid clearance (CUA) was determined in untreated patients with hyperthyroidism due to Graves' disease. Serum uric acid was significantly elevated in patients with hyperthyroidism, and the elevation correlated well with serum T4 before treatment as a group and during treatment in each patient. A significant elevation of serum uric acid was not present in patients with a transient mild thyrotoxicosis due to subacute thyroiditis. Serum uric acid was significantly decreased in patients with hypothyroidism. Renal excretion of uric acid clearly increased in hyperthyroid patients, and CUA also increased. The increase in CUA corresponded to the increase in renal plasma flow (RPF), which was measured by p-aminohippuric acid clearance. The fractional excretion of uric acid as determined by CUA/glomerular filtration rate (GFR) was similar and within the normal range in hyperthyroid patients and normal controls. A significant inverse correlation between CUA and serum uric acid concentration was present in hyperthyroid patients as in normal controls, indicating that the renal handling of uric acid in the tubule affected uric acid excretion.(ABSTRACT TRUNCATED AT 250 WORDS)

Mechanisms of elevation of serum and urinary concentrations of soluble thrombomodulin in diabetic patients: possible application as a marker for vascular endothelial injury

Serum and urinary levels of soluble thrombomodulin (TM) were measured in 71 patients with non-insulin-dependent diabetes mellitus (NIDDM) and 132 age-matched control subjects to elucidate the mechanisms involved in increased TM levels. We compared the TM level with urinary albumin excretion (UAE), creatinine (Cr) clearance, and indices of renal tubular damage such as urinary beta2-microglobulin. Serum TM was significantly higher in diabetic patients versus control subjects (P < .001) regardless of whether the patients had diabetic nephropathy. Urinary TM levels were also higher in diabetic patients than in control subjects (P < .001). Serum TM in diabetic patients was correlated positively with serum Cr and UAE and inversely with the Cr clearance rate (P < .001, respectively). The urinary level of TM in diabetic patients was significantly correlated with 24-hour glucose excretion and the serum level of 1,5-anhydroglucitol (1,5-AG) (P < .001). However, no correlations were found between urinary TM levels and renal function in diabetic patients. There was also no correlation between serum and urinary levels of TM in the patients. These results suggest that although the serum TM level is influenced by an impairment of the renal clearance of TM, this parameter may be a useful marker for vascular endothelial injury in diabetic patients. On the other hand, since the elevated urinary level of TM in the patients paralleled their urinary excretion of glucose, urinary TM levels do not correlate with vascular endothelial injury in diabetic patients.

The influence of drug-exposure conditions on the development of resistance to methotrexate or ZD1694 in cultured human leukaemia cells

The influence of drug exposure conditions on the development of resistance to methotrexate (MTX) or ZD1694 was studied by treating MOLT-3 human lymphoblastic-leukaemia cells in a continuous or a pulsatile (high-dose, short term) drug-exposure schedule. Continuous exposure of the cells to MTX with stepwise escalation of the drug concentrations resulted in a MTX-resistant sub-line (MOLT-3/MTX(10000)) with impaired reduced-folate carrier (RFC) and increased dihydro-folate-reductase (DHFR) activity. Conversely, a MTX-resistant clone (MOLT-3/MTX. P-9) with unaltered RFC and DHFR activity, but with decreased cellular accumulation of anti-folates, was selected by high-dose short-term treatment of the cells with MTX. MTX resistance in the latter cells was pronounced after short-term rather than continuous-exposure incubation with MTX, suggesting defective polyglutamation of the drug. On the other hand, 2 ZD1694-resistant sub-lines which were established by continuous (MOLT-3/ZD1694. C) or by pulsatile drug-exposure schedule (MOLT-3/ZD1694.P-9) demonstrated extremely low accumulation and poor retention of [3H]ZD1694, with no change in initial drug uptake and little or no increase of thymidylate-synthase (TS) activity irrespective of drug exposure conditions for their establishment. HPLC analysis displayed a virtual absence of ZD1694 polyglutamates in both ZD1694-resistant sub-lines and low accumulation in MOLT-3/MTX.p-9 as compared to the parent line. However, folylpolyglutamate-synthetase(FPGS) mRNA was only moderately decreased in the 2 ZD1694-resistant sub-lines and to an even lesser extent in MOLT-3/MTX.p-9. In addition, gamma-glutamyl-hydrolase(GGH) activity was not increased, but was slightly down-regulated in the polyglutamation-defective sub-lines. These results indicate that the mechanism(s) of the resistance developed may depend not only on drug-exposure conditions while raising resistance but also on the biochemical properties of the drug.

Power spectral analysis of variations in heart rate in patients with hyperthyroidism or hypothyroidism

Power spectral analysis (PSA) of the variation in heart rate is useful in determining the relative activity of the sympathetic and parasympathetic nerves. In this study, PSA was used to investigate the relationship between abnormalities in autonomic nerve function and the presence of thyroid disorders in patients with autoimmune thyroid diseases. The low frequency (LF) or high frequency (HF) components of R-R variations were determined by PSA. The coefficient of variation of the R-R time intervals (CV(R-R)) was positively correlated with HF in healthy subjects. In untreated hyperthyroid patients with Graves' disease, the CV(R-R) and HF values were significantly lower than in healthy controls. Moreover, the LF/HF ratio in patients with untreated Graves' disease was significantly higher, and the LF/HF ratio in hypothyroid patients with Hashimoto's thyroiditis was significantly lower than in healthy controls. A negative correlation was observed between serum levels of free thyroid hormones (FT4 and FT3) and HF in Graves' disease patients. In some hyperthyroid patients, antithyroid drug therapy or beta-blocker administration gradually restored reduced HF values. Present results suggest that relative vagal nerve activity is reduced in hyperthyroid patients and that this reduction is reversible according to the decrease in serum levels of thyroid hormones.

Four new furanone-coumarins from Clausena excavata

Four new furanone-coumarins, clauslactones-N (4), -O (5), -P (6) and -Q (7) were isolated from the leaves and twigs of Clausena excavata BURM. f. (Rutaceae) collected in Indonesia and their structures were elucidated by spectroscopic analysis.

Thermographic measurement of skin temperature recovery time of extremities in patients with type 2 diabetes mellitus

To elucidate the relationship between the recovery of skin temperature in an extremity after exposure to cold water and various factors associated with diabetes, we measured skin temperature in type2 diabetic patients (N=61) and control subjects (N=16). A thermo-tracer was used in thermographic measurements. The right third toe of each subject was immersed in cold water at 0 degrees C for 10 sec. Rt represents the recovery rate of skin temperature at t min after exposure. Rt was significantly reduced in the diabetic patients every 5 min in the 20 min period following exposure compared with control subjects. The diabetic patients group exhibited a significantly positive correlation between R20 and the ankle-brachial index. R20 in the diabetic patients showed a significantly positive correlation with the reduction in systolic blood pressure at the arm observed in Schellong's test. In addition, R20 showed a significantly negative correlation with plasma levels of fibrinogen and plasminogen activator inhibitor-1. However, the severity of diabetic retinopathy and nephropathy was not significantly related to R20 in the diabetic patients. The present data indicate that the recovery of skin temperature after immersion in cold water was markedly reduced in patients with type 2 diabetes mellitus as compared with healthy control subjects. Peripheral arteriosclerosis, impaired sympathetic nerve function and the activation of the blood coagulation system may all contribute to this reduced recovery of skin temperature.

A questionnaire for neurological symptoms in patients with diabetes--cross-sectional multicenter study in Saitama Prefecture, Japan

This study was designed to investigate the prevalence of neurological symptoms in diabetic patients living in Saitama Prefecture, Japan using 13-item questionnaire. A total of 6472 outpatients with diabetes (3417 men and 3055 women) were recruited from 100 centers. Mean age and mean disease duration were 60.9-year old and 10.4 years, respectively. The questionnaire for monitoring of neurological symptoms was completed at the clinic or hospital visited, and Achilles' tendon reflex, ophthalmologic, blood and urinary examinations were also performed. Of the 6472 patients, 84.8% suffered from a mean of 3.3+/-2.2 neurological symptoms. However, half of these symptoms were not considered to be those of diabetic neuropathy by attending physicians. "Feeling as if a piece of paper is attached to the sole of the foot," "stinging and prickling sensations in feet," and "pain in feet" were the most common symptoms of diabetic neuropathy. The prevalence of diabetic neuropathy as determined by attending physician increased with disease duration and worse control of diabetes. This study found that the majority of diabetics were suffered from neurological symptoms, although half of such symptoms were not considered to be those of diabetic neuropathy by physicians. Furthermore, it is important for diabetics to be diagnosed and treated earlier to prevent progression to severe neuropathic complications by means of optimal glycemic control and use of some chemicals such as aldose reductase inhibitor, and to develop this study to evaluate the efficacy of treatments.

Histopathologic characteristics of a saccular aneurysm arising in the non-branching segment of the distal middle cerebral artery

Currently, the characteristics of aneurysms arising in the distal middle cerebral artery (dMCA) are not well understood. Here, we report the case of a 56-year-old woman with a ruptured saccular aneurysm in the M2 segment of the middle cerebral artery (MCA). The patient presented with a disturbance of consciousness, and computed tomography revealed a subarachnoid hemorrhage that angiography disclosed as a result of a saccular-type aneurysmal dilatation in the M2 segment of the left MCA. We excluded infection, inflammation, trauma, and neoplasia as causes of the aneurysm. Pathologic examination confirmed a ruptured saccular aneurysm of the dMCA that was unrelated to a branching zone. The aneurysmal wall was composed primarily of alphaSMA-positive and calponin/desmin-negative spindle cells and lacked internal elastic lamina, which was completely disrupted at the neck of the aneurysm. There was a strong positive immunoreactivity for matrix metalloproteinases (MMPs) 1, 2, and 9 in the spindle cells of the aneurysmal wall. In contrast, tests for MMP-8 were negative. The parent artery showed thickening of both the intima and media, with preservation of the internal elastic lamina. Atherosclerosis was not detected in either the parent artery or aneurysm. These findings suggest that an overexpression of MMPs may contribute to the development of saccular aneurysms in regions of the arterial trunk unrelated to branching zones.

Parathyroid carcinoma with metastatic calcification identified by technetium-99m methylene diphosphonate scintigraphy

We describe herein a case of parathyroid carcinoma accompanied with metastatic calcification identified by technetium-99m methylene diphosphonate (Tc-99m MDP) scintigraphy in the lungs, kidneys and stomach. Parathyroid carcinoma remains a rare disorder despite the increased prevalence of primary hyperparathyroidism. Metastatic calcification is noted infrequently even in primary hyperparathyroidism and it may cause respiratory failure. Tc-99m MDP scintigraphy three months after surgery showed a complete disappearance of Tc-99m uptake in the stomach and an obvious reduction in the kidneys but no significant change in the lungs, indicating metastatic calcification can be reversibly reabsorbed. This case indicates that the adequate excision of parathyroid carcinoma as well as the early detection of metastatic calcification by Tc-99m MDP are obligatory.

Cellular and molecular mechanisms of resistance to antifolate drugs: new analogues and approaches to overcome the resistance

A number of antifolate drugs, which inhibit the key enzymes in the 'thymidylate cycle', dihydrofolate reductase (DHFR) and thymidylate synthase (TS), have been developed as part of the search for analogues with superior antitumor efficacy to a 'classical' antifolate, methotrexate (MTX), and those which are active against the MTX-resistant tumor cells. Recent development of newer classes of antifolate drugs is based on the extensive understanding of the relationship between chemical structures and biological properties and of analogue interactions with target enzymes, transport proteins and folate metabolizing enzyme, folylpolyglutamate synthetase (FPGS). Tumor cells may develop resistance to an antifolate drug by virtue of, (1) amplified activity in its target enzyme, (2) impaired function of drug transport protein, e.g. reduced folate carrier (RFC), (3) induction of mutated target enzyme with low affinity for antifolate(s), and (4) defective polyglutamation of drug(s) in the cells. Recent studies have elucidated in part the molecular events involved in the resistance to antifolates. These include amplification and/or mutation of the gene encoding a target enzyme, reduced or altered gene expression of the RFC, and mutated expression of the FPGS gene. To overcome or circumvent the resistance mechanisms, new antifolates with diverse structures and different biological properties have been designed and developed for clinical use. Trimetrexate (TMQ), a lipophilic DHFR inhibitor which is not a substrate for RFC and FPGS, could overcome the MTX-resistance through impaired RFC and diminished polyglutamation, and partially through amplified DHFR. Selective inhibitors of TS with a folate structure such as raltitrexed could circumvent the resistance by virtue of DHFR overproduction, and this class of compounds which have higher substrate activities for FPGS than MTX may be of value for the treatment of myeloid leukemias in addition to lymphocytic malignancies resistant to conventional chemotherapy. Several strategies to overcome antifolate resistance by using gene therapy are currently under investigation.

Peritoneal dissemination of pancreatic cancer caused by endoscopic ultrasound-guided fine needle aspiration: A case report and literature review

BACKGROUND

Endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) is a biopsy technique widely used to diagnose pancreatic tumors because of its high sensitivity and specificity. Although needle-tract seeding caused by EUS-FNA has been recently reported, dissemination of pancreatic cancer cells is generally considered to be a rare complication that does not affect patient prognosis. However, the frequency of dissemination and needle-tract seeding appears to have been underestimated. We present a case of peritoneal dissemination of pancreatic cancer due to preoperative EUS-FNA.

CASE SUMMARY

An 81-year-old man was referred to the Department of Surgery of our hospital in Japan owing to the detection of a pancreatic mass on computed tomography during medical screening. Trans-gastric EUS-FNA revealed that the mass was an adenocarcinoma; hence laparoscopic distal pancreatectomy with lympha-denectomy was performed. No intraoperative peritoneal dissemination and liver metastasis were visually detected, and pelvic lavage cytology was negative for carcinoma cells. The postoperative surgical specimen was negative for carcinoma cells at the dissected margin and the cut end margin; however, pathological findings revealed adenocarcinoma cells on the peritoneal surface proximal to the needle puncture site, and the cells were suspected to be disseminated via EUS- FNA. Hence, the patient received adjuvant therapy with S-1 (tegafur, gimeracil, and oteracil potassium); however, computed tomography performed 5 mo after surgery revealed liver metastasis and cancerous peritonitis. The patient received palliative therapy and died 8 mo after the operation.

CONCLUSION

The indications of EUS-FNA should be carefully considered to avoid iatrogenic dissemination, especially for cancers in the pancreatic body or tail.