Reciprocal modulation of somatosensory evoked N20m primary response and high-frequency oscillations by interference stimulation

OBJECTIVES

We examined whether the inverse relation between somatic evoked N20m primary response and high-frequency oscillations during a wake-sleep cycle (Hashimoto, I., Mashiko, T., Imada, T., Somatic evoked high-frequency magnetic oscillations reflect activity of inhibitory interneurons in the human somatosensory cortex, Electroenceph clin Neurophysiol 1996;100:189-203) holds for interference stimulation.

METHODS

Somatosensory evoked fields (SEFs) from 14 subjects were measured following electric median nerve stimulation at the wrist with, and without, concurrent brushing of the palm and fingers. SEFs were recorded with a wide bandpass (0.1-1200 Hz) and then N20m and high-frequency oscillations were separated by subsequent low-pass (< 300 Hz) and high-pass (> 300 Hz) filtering.

RESULTS

The N20m decreased dramatically in amplitude during interference stimulation. In contrast, the high-frequency oscillations moderately increased in number of peaks.

CONCLUSIONS

These results demonstrate the presence of an inverse relation between N20m and high-frequency oscillations for interference stimulation. We speculate that the high-frequency oscillations represent a localized activity of GABAergic inhibitory interneurons of layer 4, characterized by a high-frequency spike burst (200-1000 Hz) without adaptation, and that the continuous interference stimulation induces tonic excitation of the interneurons, leading to a facilitation of responses to the coherent afferent volley elicited by the median nerve stimulation (bottom-up mechanism). On the other hand, refractoriness of the pyramidal neurons caused directly by interference stimulation along with an enhanced feed-forward inhibition from the interneurons will lead to a decrease of N20m amplitude.

[Renal angiomyolipoma with a tumor thrombus extending into the right atrium--a case report]

We present a case of spontaneous rupture of renal angiomyolipoma with a tumor thrombus extending from the right renal vein and inferior vena cava to the right atrium. A 41-year-old woman, previously in good health, was referred to our hospital with right flank pain. Computed tomography showed fat densities in both tumor and thrombus. Other imaging examinations also demonstrated a large right renal mass (18 cm in diameter), a long tumor thrombus (13 cm in length) and a small left renal tumor (1.5 cm in diameter). Right nephrectomy and en-bloc removal of the intra caval and intracardiac tumor thrombus were performed on cardiopulmonary bypass. It was pathologically diagnosed as an angiomyolipoma without tuberous sclerosis. At present, three years after surgery the patient is doing well, showing neither metastasis nor increase of the left renal angiomyolipoma. To our knowledge, our case seems to be the 3rd case report of renal angiomyolipoma with a tumor thrombus extending to the right atrium. We conclude that renal angiomyolipoma even with an intra cardiac tumor thrombus can be resected safely and successfully.

Frequency representation in the human hand somatosensory cortex: a reappraisal

Frequency organization in the human primary somatosensory cortex (SI) was re-examined. Somatosensory evoked magnetic fields (SEFs) were measured with a 37 channel first-order axial gradiometer system. Sensory stimuli comprising a 20ms vibration at frequencies of 50, 100, 200 and 400 Hz were delivered to the volar surface of the tip of the right index finger. Using a single dipole model, the sources of the first main peak (M50) of SEFs were estimated. All of the sources were located in the 3b area. There were no statistically significant differences between the locations of the dipoles evoked by different frequency stimulations. These results support our previous study using a 122 channel whole head planar gradiometer system that systematic frequency organization at the hand area of SI cortex may not be present in humans.

Distribution of two types of mast cells in the nasal mucosa after chemosurgical treatment of allergic rhinitis using trichloroacetic acid

To evaluate the efficacy of chemosurgery using trichloroacetic acid (TCA) for allergic rhinitis, two types of tissue mast cells [tryptase-positive, chymase-negative mast cells (MCT) and tryptase-positive, chymase-positive mast cells (MCTC)] in the nasal turbinate mucosa were immunohistochemically identified and their distribution was assessed in clinical cases of patients who underwent unilateral TCA treatment. A comparison of the number of MCT and MCTC between the treated and nontreated sides indicates that both types of mast cells are significantly decreased in number in the treated side both in epithelial and lamina propria layers. The results indicate that TCA treatment was effective in suppressing MCT infiltration, regarded as a major cause of antigen-dependent allergy.

Effects of triphenyltin on growth and viability of K562 leukemia cells

The effects of triphenyltin on growth and viability of K562 human leukemia cells were examined using a flow cytometer with fluorescent dyes, ethidium bromide, fluo-3-AM, and propidium iodide. Triphenyltin at concentrations ranging from 30 nM to 1 μM inhibited the growth of K562 cells in a dose-dependent manner when the cells were incubated with triphenyltin at respective concentrations for 72 h. Triphenyltin at 100 nM slowed the rate of growth without affecting the viability. Triphenyltin at 300 nM or higher greatly decreased the viability of K562 cells. Triphenyltin at 300 nM increased the concentration of intracellular Ca(2+) and induced cell cycle arrest in G2/M phase and apoptosis in K562 cells. The concentration of triphenyltin inducing 50% inhibition of growth of K562 cells was lower than those of cisplatin, diphenyltin, monophenyltin, triethyltin and trimethyltin. However, tributyltin was equally toxic. Results suggest that there are several types of mechanisms for the inhibitory action of triphenyltin on the growth of K562 cells, being dependent on its concentration.

Autotransfusion supported by erythropoietin therapy in transurethral resection of the prostate

We investigated the collection and transfusion of autologous blood after treatment with EPO in 68 BPH patients (including 10 controls) who were scheduled to undergo TUR-P. All patients received oral and/or intravenous iron supplements. Assessments were made based on the preoperative increase in blood hemoglobin levels including autologous blood predonation (deltaHb). The deltaHb in patients undergoing collection of 600 ml of blood were as follows: control group: -0.36 +/- 0.57 g/dl; EPO group, 9 x 3000 units intravenously: 1.15 +/- 0.83 g/dl; EPO group, 6 x 6000 units intravenously: 0.79 +/- 0.80 g/dl; EPO group, 3 x 12,000 units subcutaneously: 1.47 +/- 0.62 g/dl. In patients undergoing collection of 800 ml of blood, the results were as follows: EPO group, 3 x 12,000 units subcutaneously: 1.80 +/- 0.69 g/dl; EPO group, 3 x 24,000 units subcutaneously: 2.03 +/- 0.77 g/dl. All EPO-treated patients successfully underwent surgery using their own blood, and none of them required homologous transfusion. The increase of Hb was greater in the patients treated with EPO than in controls, allowing safe preoperative blood collection even in elderly patients. In patients with relatively severe BPH, homologous transfusion could be avoided and surgery was performed safely.

[Clinical and histopathological features of hemangiopericytoma-like tumor of the nasal cavity]

A 65-year-old woman consulted our hospital complaining of left nasal obstruction. On nasal examination, a reddish half round tumor arising from the left nasal septum was found. We removed the tumor together with normal septal mucosa. Histologically, the tumor was diagnosed as a hemangiopericytoma-like tumor. It has been reported that a hemangiopericytoma-like tumor is microscopically distinguished from similar type tumors arising from other sites of the body. The most notable microscopic features of intranasal hemangiopericytoma-like tumors are their uniformity of cells and the absence of nuclear or cytoplasmic pleomorphism with a sheetlike arrangement, and no evidence of varying growth phases or necrosis. This is the second case report of this type of tumor in Japan.

Benzodiazepine effects on human sleep EEG spectra: a comparison of triazolam and flunitrazepam

The effects of 0.5 mg triazolam (TRI) and 4 mg flunitrazepam (FNZ) on the sleep electroencephalogram (EEG) were studied in eleven (six for TRI, and five for FNZ) healthy young male subjects. C3 EEG channel data of one baseline night, three drug nights and two withdrawal nights were recorded and their analyzed using a fast Fourier transformation (FFT) method. Changes in the 0.5 Hz to 40 Hz power spectrum showed that: 1) both TRI and FNZ increased higher frequency activity and reduced lower frequency activity on the drug nights; 2) on drug nights, NREM sigma frequency power was more strongly enhanced by TRI than FNZ, while the beta power of both NREM and REM was more strongly enhanced by FNZ than TRI; 3) NREM alpha power increased on the second night of withdrawal from both TRI and FNZ; 4) the power spectra for both NREM and REM sleep returned to baseline levels by the fourth night of withdrawal from either TRI or FNZ. These findings suggest that 0.5 mg TRI and 4 mg FNZ have both common and differing pharmacological effects on the central nervous system. Such differences could be caused by differences in the dose, half-life or systemic distribution of these two drugs.

[The reaction of the nasal mucosa in allergic rhinitis to cold saline stimulus]

To clarify the nature of the reaction pattern of the nasal mucosa in allergic rhinitis, nasal lavage using a cold saline solution of 4 degrees C and a warm saline solution was attempted in 8 patients with nasal allergy to the pollen of the Japanese cedar and cypress in a non-scatter season, and the concentration of protein contents in the nasal washings was determined. The concentrations of total protein, albumin and 26 kD protein were higher in cold saline than in the warm saline lavage. In particular, the concentration of 26 kD protein was 5.3 times higher. However, the concentration was not very high compared with the value obtained by warm saline lavage in the scatter season. These findings indicate that the nasal mucosa of patients with allergic rhinitis is reactive to cold saline stimuli even in the non-scatter season.

[Percutaneous ethanol and acetic acid injection for liver metastasis from colon cancer--two case reports]

Two cases of liver metastasis from colon cancer were treated by percutaneous ethanol (PEI) and acetic acid (PAI) injection for the recurrent lesion after surgery. Case 1 was a 60-year-old female who received sigmoidectomy with partial hepatectomy, and intraarterial 5-FU infusion was done after surgery. One year later, recurrence of liver tumor was detected, and PEI and PAI were performed for the metastatic lesions of the liver. Tumor regression and histopathological examination revealed coagulative necrosis. The patient died of lung metastasis 2 years and 10 months after treatment. Case 2 was a 58-year-old-male with ascending colon cancer and liver metastasis, who received surgery, and chemotherapy with intraarterial 5-FU infusion was continued. Four months later, recurrence of liver metastasis with elevation of serum CEA was noted. The patient received PEI three times and CEA decreased. Re-operation of hepatectomy revealed complete necrosis at the site of PEI. The patient has been alive for 1 year and 6 months with a new recurrence in the liver and is receiving repeated PEI therapy. PEI and PAI seem to be useful for the treatment of unresectable liver metastasis.

Long-term outcome of renal transplantation in hepatitis B surface antigen-positive patients in cyclosporin era

The impact of hepatitis B virus (HBV) infection on the outcome of renal transplantation (Tx) has been controversial. To determine the indication of renal Tx in patients infected by HBV, we investigated the long-term outcome of renal transplant patients with hepatitis B surface antigen (HBsAg). We analyzed 980 patients, including 18 HBsAg carriers, who underwent renal Tx and were immunosuppressed with cyclosporin in our institute. Fourteen out of 18 patients (77.8%) showed hepatic dysfunction after an average period of 17.8 months (range 1-65) after Tx. Four out of 14 patients (28.5%) with hepatic dysfunction died of liver failure due to fulminant hepatitis with functioning grafts between 15 and 71 months after Tx. The remaining 10 patients with hepatic dysfunction are alive up to the time of last follow-up; however, 5 of them lost their grafts because of rejection between 44 and 92 months after Tx. Their liver function improved after withdrawal of cyclosporin. Only 4 patients did not develop chronic liver disease and have had functioning grafts for between 44 and 147 months. One patient died of subarachnoid hemorrhage 22 months after Tx. HBe antigen, antibody and HCV antibody status were not related to the occurrence of liver dysfunction after Tx. Four HBV-DNA-positive patients showed deteriorated liver function. Three patients with chronic active hepatitis confirmed by the biopsy were treated with interferon. Interferon improved liver function in 2 patients, however, 1 patient died of liver failure despite interferon therapy. Our data suggested that the presence of HBsAg is often associated with chronic liver disease leading to liver failure regardless of HBe and HCV status after Tx. The indication of renal Tx in patients with HBsAg should be determined carefully giving consideration to these results.

[A preliminary study on transurethral electrovaporization of the prostate (TVP) using VaporTrode]

BACKGROUND

Surgical therapy for Benign Prostatic Hypertrophy (B.P.H.) has mainly depended upon Transurethral Resection of the Prostate (TUR-P) using a cutting loop electrode. Recently, a new technique TVP was reported using the VaporTrode apparatus. We assessed the safety and efficacy of the VaporTrode in a preliminary study.

METHODS

Histological changes of the muscle and liver of pigs were examined after vaporization using the VaporTrode and a cutting loop electrode. First, histological changes were investigated following vaporization after one stroke at a slow hand speed. Next, histological changes were assessed following vaporization at fixed stroke speed in an experimental model.

RESULTS

At an electrical output of less than 275 W, the depth of the vaporized layer increased as the stroke speed became slower (4.0 cm/s-2.5 cm/s). When the electrical output was 300 W, the depth of vaporized layer increased even at a faster stroke speed (2.5 cm/s-3.0 cm/s.) The depth of the desiccated layer increased as the stroke speed became slower at any electrical output. However, when the stroke speed was 4.0 cm/s, the depth of this layer was less than 2.0 mm. With the cutting loop electrode, the depth of the desiccated layer increased at a higher electrical power, but the change was very small.

CONCLUSION

To achieve deep enough vaporized and desiccated layers safely, the VaporTrode should be used at a stroke speed slower than 3.0 cm/s and a high electrical power of about 275 W.

Solitary cystic dilatation of the intrahepatic bile duct

A 31 year old man was hospitalised with general fatigue and epigastric pain. Abdominal ultrasonography, computed tomography, and magnetic resonance imaging showed a cystic lesion in the left lobe of the liver. Endoscopic retrograde cholangio-pancreatography and percutaneous trans-hepatic cholangiography revealed a localised dilatation of the intrahepatic bile duct without any obstruction. However, a large mass of mucinous material was noted in the saccular intrahepatic duct and the common bile duct. There was no evidence of a choledochal cyst, anomalous pancreaticobiliary ductal union, or congenital cystic change of the kidneys. A possible diagnosis of mucinous cystic neoplasm of the intrahepatic bile duct was made and a left hepatectomy performed. Cholangiography of the resected specimen showed a non-obstructive solitary cystic dilatation of the left hepatic duct. Histologically, the dilated duct was lined with columnar biliary epithelium without any papillary proliferation and/or atypia. Neither malignancy nor hepatic fibrosis was observed; the term "solitary cystic dilatation of the intrahepatic bile duct" perhaps is more descriptive and the concept easier to understand.

Plasmapheresis for prevention of recurrent focal segmental glomerulosclerosis of kidney allograft in adult recipients

Nephrotic syndrome due to focal segmental glomerulosclerosis (FGS) frequently recurs even after renal transplantation and may cause renal allograft failure. From January 1983 though April 1995, 11 adult recipients with primary FGS received 11 kidney transplants at our institution, and 3 of them were treated with pretransplant plasma exchange (PE). Other patients did not receive any preoperative PE, and 4 patients lost their grafts due to recurrent FGS (50%). PE was completed 3 times before the transplantation to prevent posttransplant recurrence of FGS. Two recipients did not have any proteinuria or graft dysfunction without posttransplant PE. One patient had mild proteinuria immediately after transplantation, and histological examination showed recurrent FGS. The patient has been undergoing PE once a month (2 years posttransplant). Her renal function is excellent (sCr 1.2 mg/dl), and her FGS is being well controlled by PE. PE seems to be effective for the prevention of the recurrence of FGS following renal transplantation.

Prevalence of urinary tract infection during outpatient follow-up after renal transplantation

Seven hundred and twenty-seven renal transplant patients are reviewed with respect to the occurrence of urinary tract infection (UTI) after renal transplantation. UTI was defined as the detection of both bacteriuria (10(5) CFU/ml) and pyuria (10 leukocytes/hpf). UTI developed in 11 of the inpatients (20.8%) and in 30 (4.2%) of the outpatients during a one-year period. Among outpatients, 12 had symptomatic infections, comprising seven with acute pyelonephritis and five with acute cystitis. Asymptomatic UTI was detected in 18 patients. In addition, asymptomatic bacteriuria without pyuria was observed in ten (1.4%) patients. UTI was more common in patients with diabetes, and underlying urinary tract complications were present in some patients. Administration of trimethoprim-sulfamethoxazole for about 4 months is suggested to reduce the frequency of UTI in the early period after renal transplantation.

[Utility of prostate specific antigen (PSA) density in detecting prostate cancer in men showing gray zone serum PSA levels]

The efficacy of prostate specific antigen density (PSAD) in diagnosing prostate cancer was assessed in 98 patients with serum prostate specific antigen (PSA) levels between 2 and 10 ng/ml who had a pathological diagnosis made by prostate biopsy or transurethral resection of the prostate. Of the 98 patients, 22 (22%) had prostate cancer. The PSA (based on a cut-off value of 4.5 ng/ml) had a sensitivity and positive predictive value (PPV) of 82% and 38%, respectively, for diagnosing prostate cancer, while the results for PSAD (based on a cut-off value of 0.13) were 91% and 61%. The PSAD was more efficient than the PSA levels and was also superior to digital rectal examination (DRE) combined with transrectal ultrasonography (TRUS), for which the sensitivity and PPV were 73% and 39%, respectively. Six (11%) out of 57 patients who were normal on DRE and TRUS had prostate cancer. In these 57 patients, the PSA (cut-off value: 4.5 ng/ml) had a sensitivity of 50% and PPV while the values for PSAD (cut-off value: 0.13) were 83% and 36% respectively. The PSAD could effectively detect even impalpable prostate cancer not visible on TRUS.

[Retroperitoneal malignant mesothelioma. A case report]

A case of primary malignant mesothelioma grew from retroperitoneal space is reported. A 39-year-old man was admitted to our hospital with the right non-functioning kidney on April, 1993. He had felt the right lumbal dull pain and scrotal pain about 6 month ago, the pain became stronger gradually. He consulted the other clinic, and there, he was pointed out of the loss of function of his right Kidney by the IVP. Examination of cystoscopy, retrograde pyelography, percutaneous antegrade pyelography, CT scan and ultrasonography suggested retroperitoneal tumor with unknown origin. His right ureter was totally obstructed by this tumor, and the right kidney had lost the function. The right nephrectomy and partial ureterectomy were done but this tumor was hard to be resected because of its sever invasion to the surrounding muscles and bones. The pathology of this tumor resulted in a Malignant Mesothelioma. After the operation several chemotherapy was done but any effectiveness was not gained. The tumor made rapid progress and he died of multiple organ failure in 8 months after the first operation. Malignant Mesothelioma generally arises from serous membrane, so almost of this tumor are found in the peritoneum and pleura. But in this case, the tumor developed in the retroperitoneum. I have given this case a great deal of consideration and due to its unusual nature I make this report.

Determination of bradykinin-(1-5) in inflammatory exudate by a new ELISA as a reliable indicator of bradykinin generation

We have developed an ELISA for BK-(1-5) (Arg1-Pro2-Pro3-Gly4-Phe5). In rat carrageenin-induced pleurisy, in which a plasma exudation peak was observed 5 h after carrageenin, BK levels in the exudates were negligible (< 60 pg/rat). BK-(1-7) (des-Phe8-Arg9-BK) was detectable (900-400 pg/rat) over the entire course of the inflammation. However, a larger amount of BK-(1-5) was detectable in association with the increase in plasma exudation, showing a peak (8800 +/- 1200 pg/rat) 3 h after carrageenin. Bromelain (10 mg/kg, i.v.) and soy bean trypsin inhibitor (0.3 mg/rat, intra-pleural) significantly reduced BK-(1-5) levels (by 60-93%, 3, 7 and 19 h after carrageenin) and plasma exudation rates (by 61-74%, 3 and 7 h after carrageenin). Dexamethasone (0.3 mg/kg, i.p.) reduced BK-(1-5) levels (by 78%) and decreased plasma exudation (by 70%) 3 h after carrageenin. In nasal allergy patients, antigen challenge of nasal mucosa elevated BK-(1-5) levels and active kallikrein levels in nasal washes. These results verify that BK-(1-5) determined by ELISA is a good indicator for release of kinins in vivo.

Flunitrazepam effects on human sleep EEG spectra. II: Sigma and beta alterations during NREM sleep

Flunitrazepam (FNZ) is known to enhance the higher EEG frequencies, including sigma (10-15 Hz) and beta (20-28 Hz). Both sigma and beta frequency bands show an inverse relationship with delta (0.3-3 Hz) during NREM periods, as we have previously reported. It is not known whether generation of these two EEG frequencies is mediated by the same or different neuronal mechanisms. In this report, we compare alterations of delta, sigma and beta EEG induced by FNZ (4 mg) orally administered to five healthy male subjects for seven consecutive nights. Sleep EEG on the baseline night (BLN), and the fourth and seventh drug nights (4DN, 7DN) was subjected to fast Fourier transform (FFT) analysis. On drug nights, sigma was enhanced without regard to delta amount, but beta was enhanced only during epochs containing low delta. Thus, sigma and beta EEG were altered differently by the same pharmacological agent. These results suggest that sigma and beta EEG are mediated by different neuronal mechanisms.

Reduction by a kallikrein inhibitor of the increased nasal airway resistance of allergic patients after antigen challenge

Kallikrein activity in nasal lavage fluid, which was measured with a synthetic substrate, Pro-Phe-Arg-methylcoumarilamide, was increased in accordance with the severity of the symptoms of house-dust-mite allergic rhinitis. Antigen challenge was applied to patients with allergic rhinitis by placing a disk containing allergen on the nasal mucosa of the right inferior turbinate. Kallikrein activities and kinin levels in the nasal lavage fluid had increased significantly 15 min after the antigen challenge. These increases were accompanied by a marked increase in nasal airway resistance 15 min after antigen challenge. Pretreatment of the patients with camostat mesilate (60 mg/kg, p.o), a non-peptide serine proteinase inhibitor clinically used in Japan, inhibited the kallikrein activity in the nasal lavage fluid. The increase in nasal airway resistance after antigen challenge was also markedly reduced by oral administration of the inhibitor, indicating involvement of the kallikrein-kinin system in induction of the nasal symptoms.

Flunitrazepam effects on human sleep EEG spectra: Differences in NREM, REM and individual responses

Flunitrazepam (FNZ) (4mg), an intermediate type benzodiazepine (BDZ) hypnotic, was administered orally to five healthy male subjects (Ss) for seven consecutive nights. Sleep EEG from the baseline night (BLN), the initial drug night (IDN), the fourth and the seventh drug nights (4DN, 7DN) was subjected to fast Fourier transform (FFT) analysis. During NREM sleep of 4DN and 7DN the sigma band (11.0-12.5 Hz) activity was similarly enhanced in every S. In REM of 4DN and 7DN beta band (23.0-29.0 Hz) was enhanced, but with larger variations among Ss. High intra-individual consistency of the relative EEG power patterns on 4DN and 7DN was observed. These results suggest that 1) EEG responses to FNZ are different in sleep states; explorations of these differences may provide better understandings of sleep mechanisms, and 2) individual variations in EEG responses may reflect individual variations of the BDZ receptor system. These methods may be useful for exploring receptor changes in neuropsychiatric disorders.