[A case of multiple sclerosis with hypothalamic amenorrhea]

We present a 31-year-old woman of multiple sclerosis. At age 28, she was admitted with complaints of echolalia and a gradual onset of weakness affecting the right upper and bilateral lower limbs. Brain MRI showed high intensity areas in the bilateral frontal gyri, lobuli paracentralis, and left anterior thalamus. Although she had been in remission for 3 years, she developed dysesthesia of left upper and lower limbs. Cervical T2 weighted MRI showed a new high signal intensity lesion in the spinal cord from the C2 to C3 level. The combination of the cerebral, thalamic and spinal cord lesions with remission and excerbations allowed the diagnosis of clinically MS to be made. She suffered amenorrhea from the onset of her illness. Serum prolactin was within the normal range. The LH and FSH basal secretions were decreased and there were low delayed secretions of LH and FSH after intravenous injection of 100 micrograms LHRH. We consider that her amenorrhea was caused by the hypothalamic lesion, supported by MR findings of dilatation of the third ventricle.

Angiographically demonstrated coronary collaterals predict residual viable myocardium in patients with chronic myocardial infarction: a regional metabolic study

Angiographical demonstration of coronary collateral circulation may suggest the presence of residual viable myocardium. The development of coronary collaterals was judged according to Rentrop's classification in 37 patients with old anteroseptal myocardial infarction and 13 control patients with chest pain syndrome. The subjects with myocardial infarction were divided into 2 groups: 17 patients with the main branch of the left coronary artery clearly identified by collateral blood flow from the contralateral coronary artery [Coll(+)group, male/female 10/7, mean age 56.6 years]and 20 patients with obscure coronary trunk [Coll(-)group, male/female 16/4, mean age 54.9 years]. Thallium-201 myocardial scintigraphy and examination of local myocardial metabolism were carried out by measuring the flux of lactic acid under dipyridamole infusion load. Coronary stenosis of 99% or total occlusion was found in only 5 of 20 patients (25%)in the Coll(-)group but in 16 of 17 patients(94%)in the Coll(+)group(p < 0.001). Redistribution of myocardial scintigraphy was found in 11 of 15 patients(73%)in the Coll(+)group, but only 3 of 18 patients (17%)in the Coll(-)group(p < 0.01). The myocardial lactic acid extraction rate was--13.2 +/- 17.0% in the Coll(+)group, but 9.1 +/- 13.2% in the Coll(-)group(p < 0.001). These results suggest that coronary collateral may contribute to minimizing the infarct area and to prediction of the presence of viable myocardium.

Aneurysm of persistent primitive hypoglossal artery

A patient with a ruptured intracranial aneurysm of the right persistent primitive hypoglossal artery is described. Clipping of the aneurysmal neck was achieved by a far lateral approach together with drilling of the jugular tubercle, and it was concluded that this approach should be followed for safe and complete clipping.

Intraoperative evoked facial muscle responses and recovery process of the facial nerve in acoustic neuroma surgery

The prognostic value of intraoperative evoked facial muscle responses (EFMR) was studied and correlated with the recovery process of the facial nerve during a follow-up period of 18 months. The patients were classified into four groups according to EFMR amplitudes, group A (150 microV or greater, 190.8, SD28.9 microV, n = 24), group B (100-149 microV, 125.7, SD14.3 microV, n = 14), group C (50-99 microV, 79.0, SD17.0 microV, n = 13) and group D (less than 50 microV, 22.1, SD13.3 microV, n = 15). Significant improved facial function appeared at 3 months after the operation in group A, at 6 months in group B, at 9 months in group C and at 12 months in group D. The early postoperative facial function and facial outcome of groups A and B were significantly better than those of groups C and D. Our data revealed that the intraoperative EFMR amplitudes have more prognostic value in predicting the recovery process of the nerve than functional outcome.

Characterization of the LolA-LolB system as the general lipoprotein localization mechanism of Escherichia coli

The major outer membrane lipoprotein (Lpp) of Escherichia coli requires LolA for its release from the cytoplasmic membrane, and LolB for its localization to the outer membrane. We examined the significance of the LolA-LolB system as to the outer membrane localization of other lipoproteins. All lipoproteins possessing an outer membrane-directed signal at the N-terminal second position were efficiently released from the inner membrane in the presence of LolA. Some lipoproteins were released in the absence of externally added LolA, albeit at a slower rate and to a lesser extent. This LolA-independent release was also strictly dependent on the outer membrane sorting signal. A lipoprotein-LolA complex was formed when the release took place in the presence of LolA, whereas lipoproteins released in the absence of LolA existed as heterogeneous complexes, suggesting that the release and the formation of a complex with LolA are distinct events. The release of LolB, an outer membrane lipoprotein functioning as the receptor for a lipoprotein-LolA complex, occurred with a trace amount of LolA, and therefore was extremely efficient. The LolA-dependent release of lipoproteins was found to be crucial for the specific incorporation of lipoproteins into the outer membrane, whereas lipoproteins released in the absence of LolA were nonspecifically and inefficiently incorporated into the membrane. The outer membrane incorporation of lipoproteins including LolB per se was dependent on LolB in the outer membrane. From these results, we conclude that lipoproteins in E. coli generally utilize the LolA-LolB system for efficient release from the inner membrane and specific localization to the outer membrane.

Facial nerve schwannoma in the cerebellopontine cistern. Findings on high resolution CT and MR cisternography

We report a case of facial nerve schwannoma originating in the cerebellopontine cistern, diagnosed by cochlear sensorineural hearing loss, and involvement in the facial nerve canal and the anterior epitympanic recess. Precise analyses of neuro-otological and neuroradiological studies are crucial to obtain an accurate preoperative diagnosis.

What can predict postoperative "endocrinological cure" in Cushing's disease?

OBJECTIVE

The goal of surgical treatment for Cushing's disease is "endocrinological cure." The purpose of this study was to determine predictors for postoperative endocrinological cure in Cushing's disease.

METHODS

Postoperative endocrinological studies were evaluated in 18 patients with Cushing's disease who underwent transsphenoidal surgery for selective adenomectomy. Serum adrenocorticotropic hormone (ACTH) levels were measured by radioimmunoassay during the first week after surgery. One week after surgery, a test using corticotropin-releasing hormone (CRH) was performed on each patient to check the reserve function of normal ACTH-secreting cells.

RESULTS

In eight patients, postoperative ACTH levels were below the measurable level for 1 week, and ACTH showed no response to the CRH test. In these patients, serum ACTH and cortisol levels were kept in the normal range with a normal diurnal variation during long-term follow-up. These patients can be defined as endocrinologically cured. In seven patients, the ACTH level returned to within normal range on the day after surgery, but ACTH was provoked by the CRH test. Five of these seven patients showed subsequent re-elevation of ACTH above the normal range. ACTH levels were never normalized in the remaining three patients, and medical treatments were unavoidable.

CONCLUSION

The most reliable indicators for predicting endocrinological cure in Cushing's disease are no response of ACTH to the CRH test in the early postoperative stage and an unmeasurably low ACTH level in the week after surgery. Obtaining a normal range of ACTH level postoperatively is insufficient to define endocrinological cure.

Increased plasma levels of mature form of adrenomedullin in patients with chronic renal failure

BACKGROUND

Adrenomedullin (AM), a novel vasodilator peptide, is produced by C-terminal amidation reaction of AM-glycine. AM-glycine, an intermediate form of AM (iAM), is processed from pro AM. AM circulating in the human blood stream was found to consist of an amidated mature form (mAM) and iAM. Biological activity is exerted only by mAM.

METHODS

To investigate the pathophysiological role of mAM in renal disease, we measured plasma concentrations of mAM as well as total AM (tAM), representing both mAM and iAM, in patients with various renal diseases. In addition, plasma ANP level was measured in all patients.

RESULTS

The concentrations of plasma mAM in renal failure with dialysis (2.1 +/- 0.2 fmol/ml, mean +/- SEM) and without dialysis (1.2 +/- 0.2) were significantly (p < 0.05) higher than those in control group (0.5 +/- 0.1). However, the plasma ANP level was increased only in renal failure patients with dialysis. Plasma mAM levels were significantly correlated positively with serum creatinine levels and negatively with hematocrit. No significant difference was noted in the ratio of mAM/tAM between renal failure patients and healthy subjects.

CONCLUSION

These results suggest that plasma mAM is increased in renal failure in relation to deterioration of renal function, while the amidation process of AM seems to be unaffected in patients with renal failure.

Plasma and urine levels of adrenomedullin and proadrenomedullin N-terminal 20 peptide in chronic glomerulonephritis

Proadrenomedullin N-terminal 20 peptide (PAMP) is a novel hypotensive peptide present in the precursor of adrenomedullin (AM), a vasodilative and natriuretic peptide. We examined the plasma and urinary levels of these peptides in patients with chronic glomerulonephritis (CGN). The mean plasma AM concentration of the patients with CGN did not differ from that of control subjects (4.17 +/- 0.17 v 3.87 +/- 0.21 fmol/mL, respectively), whereas urinary AM excretion was significantly less in the patients with CGN (5.96 +/- 0.95 v control, 8.93 +/- 1.02 fmol/mg of creatinine; P < 0.05). Plasma concentrations and urinary excretion of PAMP were significantly less for the patients with CGN compared with control subjects (0.91 +/- 0.08 v 1.23 +/- 0.20 fmol/mL; P < 0.05 and 25.0 +/- 3.0 v 35.0 +/- 3.6 fmol/mg of creatinine, respectively; P < 0. 05). The plasma AM concentration was negatively correlated with plasma renin activity (r = -0.58; P < 0.01) and aldosterone concentration (r = -0.40; P < 0.05). Urinary excretions of AM and PAMP showed significant correlations with urine excretion of sodium (r = 0.39; P < 0.05 and r = 0.49; P < 0.01, respectively). These findings suggest that AM and PAMP may have roles in the regulation of sodium in patients with CGN.

Subthalamic nucleus stimulation for gait disturbance in Parkinson's disease

OBJECTIVE

A preliminary study of subthalamic nucleus (STN) stimulation was performed to determine its applicability for the treatment of gait and postural disturbances in Parkinson's disease.

METHODS

Five Parkinson's disease patients with freezing gait and postural instability were selected for this study. Their ages ranged from 60 to 73 years (mean+/-standard deviation, 65.6+/-4.8 years). Semi-microelectrode recording was used to identify the STN and to place a chronic electrical stimulation electrode within the right STN in all patients. The Unified Parkinson's Disease Rating Scale and the modified Hoehn and Yahr Staging Scale were used to assess patients in on- and off-drug conditions before surgery and 3 months after surgery.

RESULTS

The scores on the Hoehn and Yahr Staging Scale and the total Unified Parkinson's Disease Rating Scale for akinesia (P < 0.05), gait (P < 0.05), and gait and posture (P < 0.01) in off-drug on-stimulation conditions significantly improved over the preoperative and postoperative off-drug off-stimulation conditions (analysis of variance [ANOVA], P < 0.01). Improvement over the preoperative scores was 24% on the Hoehn and Yahr Staging Scale, 43.6% on the total Unified Parkinson's Disease Rating Scale, 33.4% for akinesia, 36.6% for gait, and 38.7% for gait and posture. However, stimulation in the on-drug phase did not show a significant difference compared with pre- and postoperative conditions (ANOVA, P > 0.05). Comparisons between preoperative on-drug and postoperative off-drug on-stimulation conditions revealed that there were no significant differences in the scores, except for gait (ANOVA, P < 0.05). The scores on subscales for falling, freezing, walking, and gait in off-drug on-stimulation conditions were significantly improved over the scores for preoperative and postoperative off-stimulation (ANOVA, P < 0.05), but the score for postural stability remained unchanged.

CONCLUSION

Our findings showed that STN stimulation effectively alleviates freezing gait and improves walking to its status during the preoperative on-drug phase and can be applied for treatment of Parkinson's disease patients with these symptoms.

Conservation treatment intensified with tamoxifen and CAF chemotherapy without axillary dissection for early breast cancer patients with clinically-negative axillary nodes

Axillary node dissection has been a routine part of breast cancer treatment for more than 100 years. As so few patients have been shown to have positive nodes, more consideration should be given to eliminating axillary node dissection for duct carcinoma in situ (DCIS) and T1a lesions. And for patients with a T1/2N0M0 cancer of the breast, lumpectomy alone without axillary dissection followed by radiation therapy to the intact breast and regional lymph nodes should be a reasonable treatment method that avoids arm morbidity. Between September 1989 and December 1998, we treated 79 breast cancer patients with this method intensified with tamoxifen and CAF chemotherapy. Before the start of the therapy, we performed a thorough evaluation using helical CT and doppler ultrasonography to exclude patients with significant swelling of axillary lymph nodes (more than 5 mm in short diameter). Through the end of December 1998, the mean follow-up period was 52.6 months. Up to this date, only one patient of the 79 showed local recurrence within 5 years after the start of the treatment. This patient received a second lumpectomy. She then experienced lung metastases 6 months later. She is currently receiving combined chemotherapy with docetaxel and cisplatin. The cause-specific survival rate of these 79 patients maintained 100% at 6 years, and no axillary failure has been experienced so far. The cosmetic results in 50 (65.8%) of the 76 patients who were alive at the end of December 1998 were rated as excellent, 26 (34.2%) as good, and none as fair or poor. Therefore, we have concluded that this method of treatment for early breast cancer could eliminate surgical damage and allow good cosmetic results, and that survival rates with this treatment are excellent.

Visual evoked oscillatory responses of the human optic tract

Optic tract oscillatory responses directly recorded during posteroventral pallidotomy were investigated to reveal their features with respect to extracranially recorded visual oscillations and to clarify their contributions to scalp-recorded or far-field visual evoked potentials. Oscillatory responses of the optic tract consisting of early and subsequent late oscillations were recorded in all patients. Early oscillations consist of five negative and positive peaks, and late oscillations consist of two to four negative and positive peaks. The frequency of the first peak of early oscillations (103.0+/-9.2 Hz, n = 14) was significantly lower than that of others (t test, P<0.006), but there were no significant differences among other peaks (t test, P>0.4). This difference was not observed among peaks of late oscillations (t test, P>0.3). As a whole, the frequency of early oscillations (123.9+/-16.7 Hz, n = 70) was significantly higher than that of late oscillations (66.3+/-13.7 Hz, n = 41) (t test, P = 0.0001). Intracerebral recording of the optic responses with the same band filter of scalp-recorded visual evoked potentials (10 Hz to 1 KHz) showed prominent negative (No) and positive (Po) waves, whereas responses obtained over the scalp at Oz and Cz consisted of negative (NI), positive (PI), negative (NII), and positive (PII) waves. Comparisons between No and PI and Po and NII showed overall phase reversal relations between them, but there were significantly different peak latencies between them (t test, P<0.001) except that between Po (116.7+/-11.7 msec, n = 5) and NII of Cz recording (118.4+/-9.4 msec, n = 5) (t test, P<0.3). Our study in conjunction with other studies on visual oscillations revealed that a relatively constant frequency of oscillations is traveling in the subcortical visual system and is probably playing an important role in generating stationary or fixed peaks of the far-field potentials of visual evoked potentials.

Effect of simvastatin on proliferative nephritis and cell-cycle protein expression

BACKGROUND

Mesangial cell proliferation is important in subsequent mesangial matrix expansion in glomerular injury. Therefore, the regulation of mesangial cell proliferation may be critical in the treatment of glomerulonephritis. Inhibition of 3-hydro-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibits the production of mevalonate and has been shown to suppress proliferation in many cell types, including mesangial cells in vitro. It is expected that HMG-CoA reductase inhibitor may suppress mesangial cell proliferation and subsequent progression of glomerulonephritis. Recently, the tight relationship between cell-cycle regulatory protein expression and mesangial cell proliferation in experimental glomerulonephritis was demonstrated. The aim of the present study is to examine the effect of simvastatin, one of the HMG-CoA reductase inhibitors, on the glomerular cell proliferation and on the expression of CDK2 or p27Kip1 in mesangial cells in experimental glomerulonephritis in vivo.

METHODS

The effect of simvastatin on a rat mesangial proliferative glomerulonephritis induced by antithymocyte antibody (anti-Thy 1.1 GN) was studied. Administration of simvastatin or vehicle (for control GN) were started from two days before disease induction, and was continued to the day of nephrectomy. Nephrectomy was done at days 0, 2, 4, 7, 12 and 20 after disease induction. Immunohistochemistry for proliferating cells, macrophages, alpha-smooth muscle actin, type IV collagen and PDGF-B chain was performed, respectively, in addition to conventional periodic-acid Schiff staining. Double immunostaining for CDK2/OX-7 or p27Kip1/OX-7 was also done, respectively.

RESULTS

There was no difference in the degree of the initial injuries between simvastatin-treated and control GN rats. The most pronounced feature of simvastatin-treated GN was the suppression of the early glomerular cell proliferation (about 70% of proliferation was suppressed at day 4). At day 4, alpha-smooth muscle actin expression was also decreased in simvastatin-treated GN rats. Inhibition of macrophage recruitment into glomeruli by simvastatin was also a prominent feature (about 30% decrease in the number of glomerular macrophages at day 2). Simvastatin significantly suppressed subsequent mesangial matrix expansion and type IV collagen accumulation in glomeruli. Although it might simply reflect the reduction in mesangial cells, glomerular PDGF-B chain expression was reduced. There was no significant difference in plasma lipids levels at day 2 and day 4. In vehicle-treated GN rats, the number of CDK2+/OX-7+ cells (CDK2-expressed mesangial cells) in glomeruli increased significantly from day 4 to day 7. Although simvastatin suppressed mesangial cell proliferation, the increase in the number of glomerular CDK2+/OX-7+ cells was also attenuated by simvastatin treatment. There was no difference in the number of p27Kip1+/OX-7+ cells (p27Kip1-expressed mesangial cells) in the glomerulus between vehicle-treated and simvastatin-treated GN rats.

CONCLUSION

Simvastatin suppressed mesangial cell proliferation and subsequent matrix expansion, and macrophage infiltration into glomeruli in anti-Thy 1.1 GN rats. The antiproliferative effect of simvastatin in this model was also associated with the reduction of CDK2 expression in mesangial cells.

Prefrontal dysfunction following unilateral posteroventral pallidotomy in Parkinson's disease

OBJECT

Pre- and postoperative cognitive function was evaluated in 25 patients with Parkinson's disease (PD) who underwent unilateral posteroventral pallidotomy (PVP) to clarify the effects of this operation on cognitive function.

METHODS

Cognitive function was assessed before surgery and 1 month and 3 months afterward by using a battery of neuropsychological tests consisting of orientation, digit span (forward and backward), digit learning, 5-minute memory of five words, similarities, serial sevens, animal name listing, and the kana pick-out test, as well as the Japanese version of the Mini-Mental State. Preoperative evaluation revealed that patients experienced difficulties in performing the neuropsychological tasks of reasoning and abstraction, working memory of numerals, word fluency, and concept formation compared with 36 healthy volunteers (p < 0.05). A simple regression analysis showed strong relationships in a negative fashion between preoperative (r = 0.81, p = 0.002) and 1-month (r = 0.79, p = 0.0059) and 3-month (r = 0.85, p = 0.0016) postoperative gross-total scores and Hoehn and Yahr staging. Preoperative and postoperative scores at 1 month and 3 months were analyzed by analysis of variance, but only the Fisher's post hoc test revealed the source of difference. All tasks except orientation (p = 0.0292) were unchanged in the 10 patients who underwent surgery on the right side. The scores for this task at 1 month postsurgery were significantly lower (p = 0.0203) but improved to preoperative values by 3 months. In the 15 patients who underwent surgery on the left side significant differences among tasks were revealed for serial sevens (p = 0.0471) and animal naming (p = 0.0425). The scores for these tasks were significantly lower at 1 month postoperatively (p = 0.0431 for serial sevens and p = 0.0408 for animal naming), but improved by 3 months after the operation.

CONCLUSIONS

The present data revealed that cognitive dysfunction in patients with PD relates to advancement of Hoehn and Yahr stage, but PVP is not associated with significant long-lasting cognitive deficits.

[Exercise-induced acute renal failure associated with renal vasoconstriction]

Exercise-induced acute renal failure without rhabdomyolysis is not a rare condition. We experienced 6 cases (5 men and a woman) during last the 8 years. All cases complained of severe loin pain and nausea after mild to moderate exercises (for example, a track race in an athletic meeting). The elevation of serum and urinary myoglobin was undetected. In 4 of 5 patients with abdominal CT, renal patchy vasoconstriction (wedge-shaped low-density lesion) was observed. This was diagnosed as exercise-induced acute renal failure with loin pain (serum creatinine levels: 1.7-8.6 mg/dl). The renal function in 5 of the 6 cases normalized in about three weeks by fluid replacement therapy and hemodialysis support, which one patient received for 3 days. One patient required a long time for improvement of renal function and renal insufficiency persisted (serum creatinine 1.8 mg/dl). In 2 patients, the concentration of serum uric acid became very low after the recovery of renal function. These two patients were diagnosed as an isolated hyperuricosuric hypouricemia. More than half of the 6 patients had previously experienced the same episodes (loin pain and nausea) after exercise. Exercise-induced acute renal failure, probably due to renal patchy vasoconstriction, seems to be not a rare disease. The etiology of renal patchy vasoconstriction after exercises remains to be elucidated. The occurrence of acute renal failure must be taken into consideration when the youngster, especially with renal hypouricemia, complains of severe loin pain and nausea after exercise such as a track race.

High cervical disc lesions in elderly patients--presentation and surgical approach

The incidence of high cervical disc lesions is extremely rare, and the mechanism of their development is unclear. We report these three cases, and discuss the possible mechanisms. We also describe surgical strategies for these lesions. The first and second cases were an 82-year-old male and an 84-year-old male with retro-odontoid disc hernia. The third was an 83-year-old female with a herniated disc at C2/C3. To investigate Aetiological mechanisms of these lesions, we examined the findings on cervical images in extension and flexion, and compared the results in a younger than 80-year-old group and an older than 80-year-old group. The patients underwent surgery via a posterolateral intradural approach. Wide laminectomy and incision of the dentate ligaments enabled access to the ventral space of the upper cervical spinal canal and sufficient decompression. All patients became ambulatory postoperatively without special fixation of the cervical spine. In the younger group, the level mostly loaded during cervical movement was C5/6, however, the levels in the older group were C2/3 and C3/4. In elderly patients, less mobilization of the middle and/or lower cervical spine due to spondylotic change causes overloading at higher levels resulting in high cervical disc lesions. Retro-odontoid disc lesions can be caused by a herniated disc at C2/C3, which migrates upward. Regarding surgical strategy, the posterolateral intradural approach is less invasive and more advantageous for these lesions.

Disappearance of rhythmic involuntary movements during sleep in a case of olivopontocerebellar atrophy

We report on a 54-year-old woman with an 8 or so year history of olivopontocerebellar atrophy associated with the rhythmic involuntary movements of the left upper and lower limbs, and cervical region. Surface electromyogram of the left upper limb revealed rhythmicity (about 3 Hz) and reciprocity between antagonistic muscles, which disappeared on polysomnography at all sleep stages including rapid eye movement sleep without atonia. These were characterized by the co-existence of rhythmic skeletal myoclonus and parkinsonian tremor. These findings suggest that a disturbance of the striatonigral system as well as the dentato-rubro-olivary circuit may be involved in these movements. It also seems that their fate is dependent on the level of wakefulness and that the ascending reticular activating system also plays a role in the development of these movements.

A case of nocturnal polyuria in olivopontocerebellar atrophy

We report a case of olivopontocerebellar atrophy without sleep apnea syndrome who presented nocturnal polyuria. It is considered that a disturbance in the circadian rhythm for arginine vasopressin secretion due to degeneration of suprachiasmatic nuclei and marked increase in the secretion of atrial natriuretic peptide due to abnormal diurnal variation in blood pressure may be involved in the mechanism of nocturnal polyuria.

Visual evoked potentials during posteroventral pallidotomy for Parkinson's disease

OBJECTIVE

To examine the efficacy of intracerebral recording of visual evoked potentials (VEPs) during posteroventral pallidotomy comparing macro- and microelectrode stimulation.

MATERIALS AND METHODS

The optic tract was identified by intracerebral recording of VEPs in 16 patients. Electrical stimulation through a lesioning electrode (macroelectrode stimulation: biphasic wave, 50 Hz, 0.2 ms, 0-6 V) and a microelectrode (microelectrode stimulation: impedance of 1 M(omega) at 300 Hz, biphasic pulse, 300 Hz, 0.2 ms, 10-50 microA) was delivered to assess visual responses.

RESULTS

VEPs were recorded in every patient from 18.0+/-3.3 mm (n = 14) to 22.8+/-3.4 mm (n = 14) in the mediolateral direction. The mean amplitude at this midpoint (57.7+/-15.4 microV, n = 35) was significantly higher than other amplitudes (t test, P < 0.05). Significant increment of amplitudes appeared at 4 mm (64.3+/-18.5 microV, n = 16) below the initial target along trajectories that pass close to the midpoint of the optic tract. The distance from the initial target to the dorsal surface of the optic tract along these trajectories ranged from 3 to 6 mm, with a mean of 5.0+/-0.7 mm (n = 16), whereas adjusted distances perpendicular to the intercommissural plane ranged from 1.3 to 4.1 mm, with a mean of 3.0+/-0.7 mm (n = 16) below, and the distance from the optic tract to the intercommissural plane ranged from 6.3 to 8.7 mm, with a mean of 7.5+/-0.7 mm (n = 16). Macroelectrode stimulation evoked visual responses at various sites in the pallidal region, totaling 27 sites in 11 of 16 patients (68.7%). Microelectrode stimulation evoked responses at only five sites in 3 of 13 patients (23.1 %), within a very limited area 4 to 7 mm below the target where the electrode was very close to the optic tract. Physiological targeting of VEPs necessitated change of the initial target in 13 of 16 patients (81.2%).

CONCLUSION

VEPs of prominent oscillatory potentials with high amplitudes indicate the location of the optic tract, which allows easy identification of the optic tract and facilitates neurophysiological targeting of the globus pallidus internus in conjunction with microelectrode recording.

Neurovascular decompression for trigeminal neuralgia in elderly patients

The operative findings and outcomes of neurovascular decompression for trigeminal neuralgia were compared between patients aged 75 years and older (elderly group, 17 patients) and patients aged under 75 years (nonelderly group, 115 patients). There were no statistically significant differences in the operative findings or outcomes between the two groups, except in the percentage of patients who had been treated with carbamazepine. Neurovascular decompression for trigeminal neuralgia can be performed in elderly patients with the same operative results as in nonelderly patients. If other treatments (especially carbamazepine treatment) prove ineffective, neurovascular decompression should be considered in elderly patients before they become too old to undergo surgery. However, neurovascular decompression in elderly patients requires great care, as the venous system, including the superior petrosal vein, should be preserved and retraction of the cerebellum should be avoided whenever possible to maintain correct blood circulation in the cerebellum and brainstem.

Expression of bcl-2 and bax in glomerular disease

Bcl-2 may account in part for the maintenance of hypercellularity in human glomerular diseases through preventing cell death and by counteracting bax which may be expressed to regulate excessive proliferation. This process is associated with the effect of PDGF B-chain expression. Bax expression may be important in the cell loss leading to glomerulosclerosis and TGF-beta1 participates in this process by increasing bax expression. Thus, the balance of bcl-2/bax expression may be critical in the course of human glomerular diseases.

Neural activity of the subthalamic nucleus in Parkinson's disease patients

The neural activity pattern of the subthalmic nucleus (STN) was investigated in five patients with Parkinson's disease who were scheduled for electrode implantation for chronic stimulation of the STN. The initial target was placed 8 mm or 10 mm lateral to the midline, 3 mm to 4 mm posterior to the midcommissural point, and 5 mm to 6 mm below the intercommissural (AC-PC) line. The STN was identified by semi-microelectrode recordings with a trajectory moving laterally in 2-mm steps. The amplitudes of multi-unit activities were relatively low at depths from 8 mm to 5 mm above and from 1 mm to 4 mm below the target, while those 4 mm to 0 mm above the target were significantly higher than at the other sites (ANOVA, Fisher's test, p < 0.05), with the highest amplitude at 2 mm above the target (91.0 +/- 23.3 mu v, n = 15). In the mediolateral direction, amplitudes were relatively higher in the lateral portion, and amplitudes at 14 mm lateral to the midline were significantly higher than at the other sites (ANOVA, Fisher's test, p < 0.05). The target for chronic electrical stimulation was determined to be at the midpoint of the hyperactive STN, i.e., 12 mm lateral to the midline in three patients and 13 mm lateral in two patients. Movement-related neural activity was observed at 5 sites, i.e., 3 sites responded to passive movement of the contralateral wrist and 2 sites to passive knee and/or ankle movement. In conclusion, our data show that the lateral part of the STN is hyperactive in PD, and recordings of neural activities contributed greatly to identifying the STN and determining the target for chronic stimulation within it.

Plasma and urine levels of uroguanylin, a new natriuretic peptide, in nephrotic syndrome

Uroguanylin, a new natriuretic peptide originally isolated from urine, stimulates the membrane guanylate cyclase C receptor. No information, however, is available on the plasma and urine levels of uroguanylin in nephrotic syndrome (NS), the state associated with sodium and water retention. Using a sensitive radioimmunoassay, we measured the plasma and urine concentrations of immunoreactive (ir-)uroguanylin in NS patients and compared them with those of patients with non-nephrotic glomerulonephritis. Plasma ir-uroguanylin, blood pressure and the cardiothoracic ratio were higher, and urine excretion of ir-uroguanylin was lower in the NS patients. Plasma ir-uroguanylin in the NS patients significantly decreased during remission as compared with findings on admission. There was a significant inverse correlation between the concentration of plasma ir-uroguanylin and that of serum total protein or albumin. Moreover, fluid retention in the NS patients was correlated with the changes in plasma ir-uroguanylin between admission and remission, indicative that the plasma concentration increases with the severity of the nephrotic state. Taking into account its potent natriuretic effect, these findings suggest that uroguanylin may function in the pathophysiological mechanism in NS.