Graph-based analysis of kinetics on multidimensional potential-energy surfaces.

The aim of this paper is twofold: one is to give a detailed description of an alternative graph-based analysis method, which we call saddle connectivity graph, for analyzing the global topography and the dynamical properties of many-dimensional potential-energy landscapes and the other is to give examples of applications of this method in the analysis of the kinetics of realistic systems. A Dijkstra-type shortest path algorithm is proposed to extract dynamically dominant transition pathways by kinetically defining transition costs. The applicability of this approach is first confirmed by an illustrative example of a low-dimensional random potential. We then show that a coarse-graining procedure tailored for saddle connectivity graphs can be used to obtain the kinetic properties of 13- and 38-atom Lennard-Jones clusters. The coarse-graining method not only reduces the complexity of the graphs, but also, with iterative use, reveals a self-similar hierarchical structure in these clusters. We also propose that the self-similarity is common to many-atom Lennard-Jones clusters.

Connectivity graph: multiple connectivity on potential energy surface does affect the dynamics.

A mapping called a connectivity graph is proposed to visualize the complicated networks between local minima via saddles on many-dimensional potential energy surfaces. With this mapping, the effect of the topography of a complex potential energy surface on the dynamics is studied in model funnel potentials and a Lennard-Jones cluster. We present strong evidence that energetically expensive but dynamically relevant saddles are indispensable for kinetic dynamics. The results show that the connectivity graphs provide a sound basis for understanding nonequilibrium dynamics.

Computational method for multidimensional quantal dynamics of polynomially interacting oscillator systems.

We propose a numerical algorithm for computing quantal dynamics, which is tailored for a generic multidimensional model of low-energy dynamics, i.e., polynomially interacting oscillator system. This algorithm evaluates symplectic integrators effectively, by using block tridiagonality of the interaction operator, and thus accurately preserves unitarity with time. A practical advantage of this method is that high-order integrators are easily implemented even for time-dependent parameter systems. We demonstrate the accuracy and usefulness by applying it to a phi(4) model.

New method for computing finite-time Lyapunov exponents.

We present a novel method for computing finite-time Lyapunov exponents and vectors, via generalizing a correction given by Goldhirsch, Sulem, and Orszag [Physica (Amsterdam) 27D, 311 (1987)]] into higher-order corrections. This method is a generalized LR method, which is, in contrast to the existing methods, applicable to multidimensional systems with degenerate spectra. The efficiency and accuracy is demonstrated by applying it to multidimensional dynamical systems. Without these corrections, we could not accurately detect, as an example, the coexistence of qualitatively different Lyapunov instabilities along a trajectory for a multidimensional oscillator system.

[A case of clinically diagnosed corticobasal degeneration with unilateral cortical reflex myoclonus showing so-called giant SEP].

We report a 66-year-old woman clinically diagnosed as having a corticobasal degeneration (CBD), who showed electrophysiologically cortical reflex myoclonus. She developed a clumsiness and action myoclonus on the right extremities, and aphasia. The extrapyramidal signs such as dystonia and rigidity were also noted on the right side. Sequential MR images showed a progressive brain atrophy in the left frontoparietal area, where a blood perfusion was reduced on single photon emission computed tomography (SPECT). The median nerve stimulation on the affected right side, but not left side, elicited an enhanced long-loop reflex. The onset latency of the long-loop reflex (43.8msec) was similar to that of the reported cases of CBD (Thompson et al, 1994); but, significantly shorter than that reported in the patients with typical cortical reflex myoclonus. The right median nerve stimulation also elicited so-called giant somatosensory evoked potentials (SEPs). On the basis of the scalp topography of the giant SEPs, we found the high amplitude central P22-N30 components to reflect a radial dipole. We also recorded the myoclonus-related cortical spike by jerk-locked back averaging. Both the giant SEP and myoclonus-related cortical spike were recorded only on the left scalp. We therefore suggest that these two cortical activities are similar in terms of wave form, scalp topography and time relationship to either the long-loop reflex or myoclonus and may be located in the precentral area. This is the first report of a patient with CBD presenting both the giant SEP and myoclonus-related cortical spike.

Surface-rendering imaging of gastrointestinal lesions by three-dimensional endoscopic ultrasonography.

BACKGROUND AND STUDY AIMS: In three-dimensional endoscopic ultrasonography (3D-EUS), a surface-rendering method can provide both a surface image and a cross-sectional ultrasonographic image. We evaluated the usefulness of this imaging method for digestive tract lesions. PATIENTS AND METHODS: A total of 30 patients underwent 3D-EUS with surface-rendering using a 3D probe system which arranged individual radial scanning images into 128 points on a computer monitor to outline the surface of a lesion. A complete surface image of the lesion was displayed on the computer monitor using lines obtained from 40 radial scanning images. RESULTS: Surface-rendering images of lesions were similar to endoscopic images. The surface-rendering method permitted precise correlation of two-dimensional images depicting a slice of a lesion with the corresponding surface of the lesion. Unlike conventional endoscopy, this approach permitted observations of lesions at any desired angle. Complete images of lesions were achieved in 14 patients and were half-completed in another five, but could not be obtained in 11 patients: in six the distance between the lesion and the 3D probe was too short to avoid artifacts, while in five the lesion was larger than the longitudinal scanning length of 4 cm or greater than 90 in extent in radial scanning images. Artifacts caused by heartbeat led to irregular images in four patients, including three with esophageal cancer and one with gastric cancer. CONCLUSIONS: Despite some problems, surface-rendering imaging should prove useful for diagnosis, and the method will improve as software is perfected.

"Pseudo" hypertrophic neuropathy of childhood.

A 9 year old boy had chronic progressive motor-sensory neuropathy that started in early infancy. He had enlarged nerves and pes cavus deformity. Motor conduction studies showed very dispersed, polyphasic compound muscle action potentials with conduction velocities around 2 m/s. A sural nerve biopsy showed severe loss of myelinated fibres. Two months of treatment with corticosteroids restored muscle power. During this time the enlarged nerves became normal and electrophysiological recovery was achieved. Chronically acquired neuropathy in infancy is strikingly similar to genetically determined neuropathy.

Acute sensory neuropathy: 2 year follow-up of sensory conduction.

Following flu-like illness a 75 year old man developed pure sensory neuropathy that reached a peak at 3 weeks. Cerebrospinal fluid protein was elevated with no increase in cell count The sensory deficits started to improve 4 months later, and were completely resolved 12 months later. Compound sensory nerve action potential, which had been absent initially, became detectable 8 months after the onset The revived sensory potentials progressively increased their size during the 2 year period. A variant of acute inflammatory demyelinating polyneuropathy may be part of a syndrome of acute sensory neuropathy.

[Chronic inflammatory demyelinating polyneuropathy in childhood--a case with markedly hypertrophic nerves and pes cavus].

We describe a 9-year-old boy with chronic inflammatory demyelinating polyneuropathy (CIDP), whose distal dominant, slowly progressive motor sensory involvement developed since infancy. Thickened peripheral nerves were visible in his neck and palpable in the extremities. The hand muscles were atrophic and both feet showed pes cavus deformity. He was unable to walk. Nerve conduction study revealed no sensory potentials. Compound muscle potential (CMP) was absent in the legs. In the arms, CMP showed markedly low amplitude and temporal dispersion. Motor conduction velocities were 1.7 to 2.7 m/sec, showing extremely high threshold to electrical stimuli. Conduction block was not convincing, nevertheless the asymmetric conduction abnormalities strongly suggested multifocality of the lesion. In the biopsied sural nerve no myelinated fibers were found. Considerable improvements in muscle power and electrophysiological findings were brought about by corticosteroid therapy. CIDP in childhood may masquerade hereditary neuropathies presenting hypertrophic peripheral nerves and pes cavus deformity. A careful nerve conduction study is thus desirable to find out electrophysiological multifocality.

[High-dose intravenous immunoglobulin treatment in chronic inflammatory demyelinating polyneuropathy].

We treated two patients with chronic inflammatory demyelinating polyneuropathy (CIDP) with high-dose intravenous immunoglobulin (HIG). The patients received 400 mg/kg of immunoglobulin a day for five days. One patient, who had failed to respond to prednisolone before, was treated with HIG, 18 months after the onset. His motor symptoms resolved immediately after the commencement of HIG. Electrophysiologically, the compound muscle action potentials increased in amplitude in all nerves examined and F wave reappeared in the left median nerve. The electrophysiological changes were compatible with improvement of conduction blocks. This patient had headache and exanthema during the HIG therapy, but they settled after cessation of the infusion. The other patient was administered HIG as an initial treatment, four months after the onset. HIG was of no effect in this case, but he showed remarkable recovery during the following prednisolone therapy. Although corticosteroid therapy is the first choice for CIDP, there are CIDP patients who do not respond to steroid or can not complete the steroid therapy because of adverse effects. HIG is an expectative and recommendable treatment for the steroid resistant CIDP patients.

Coexisting acromegaly and a unilateral cortisol-producing adrenal adenoma: a possible variant of multiple endocrine neoplasia type I.

An unusual case of coexisting acromegaly and Cushing's syndrome is reported in a 34-yr-old female. There was no biochemical or morphological evidence to suggest the presence of other endocrinopathies. She did not have any family history to suggest a hereditary tendency to endocrine disorders. Her acromegaly and Cushing's syndrome were proven to be due to a pituitary somatotroph adenoma and a cortisol-producing adenoma in the right adrenocortex, respectively. Surgical removal of both tumors led to a marked biochemical improvement of the two endocrinopathies. To account for the simultaneous occurrence of the two endocrine tumors, at least two endocrine syndromes may be considered. One of them is Carney's complex. However, Cushing's syndrome in this complex is unexceptionally due to primary pigmented nodular adrenocortical disease, differing from the adrenal pathology of our patient. In addition, a lack in this case of any other characteristic suggestive of this syndrome appears to speak against this possibility. A second possibility is multiple endocrine neoplasia type 1. The absence of a parathyroid or pancreatic islet cell tumor does not strongly support this possibility, but adrenocortical lesions are not rare in this syndrome although they are only rarely functional. However, existence of similar case reports, although very few, in the literature leaves the possibility that she represents another rare variant of sporadic multiple endocrine neoplasia type I syndrome.

A null cell adenoma of the pituitary detected seven years after removal of a prolactinoma. Recurrence or de novo tumourigenesis?

We report an extremely unusual case of prolactinoma which emerged at recurrence as a null cell adenoma. A 53-year-old woman sought medical attention for progressive visual loss and headache. A pituitary tumour was detected by a computed tomographic scan, and hyperprolactinemia was noted. The tumour, removed by a transfrontal surgery, was a chromophobe adenoma, and immunohistochemically the adenoma cells were selectively positive for PRL, which indicated a prolactinoma. Postoperatively, her plasma PRL level was normalized. Seven years later, she noted blurred vision and again sought medical attention. A CT scan demonstrated recurrence of a pituitary tumour. On this occasion, however, she was not hyperprolactinemic. She underwent again a transfrontal resection of the pituitary tumour. Its histology was again a chromophobe adenoma, but the adenoma cells showed no positive immunostaining for any anterior pituitary hormone including PRL, which indicated a null cell adenoma. We have no clear explanation of the pathogenesis underlying her very unusual course. However, null cells (assuming that the original tumour was a mixed adenoma) left behind at the first surgery, or unidentified hypothalamic and/or pituitary derangements might possibly have been responsible for the recurrence. We learned from this patient that recurrent pituitary adenomas may not necessarily have the same endocrine features as did the original tumours. This information appears to make a valid clinical point, because if hormone levels alone are followed after pituitary surgery, recurrent pituitary tumours may be overlooked.

Evaluating marine traffic safety at channels.

An approach for measuring effects of policy schemes for improving marine traffic safety at channels is presented. Operational models involving traffic, channel, and ship characteristics are provided, and both collision and channel deviation risks of actual channels are quantified using them. Moreover, traffic control, speed regulation, and center line indication are considered as channel safety policies, and their effects are also measured using the models. The results suggest that the speed regulation scheme is effective in reducing accident risk in channels. It is concluded that methodology demonstrated and knowledge obtained in this study are useful for planning and safe operation of channels.

[A comparative study between cefodizime (CDZM) and cefotaxime (CTX) in respiratory tract infections].

The clinical efficacy and safety of Cefodizime (CDZM), a new cephem antibiotic, was objectively compared with that of Cefotaxime (CTX) in patients with respiratory infections under a well-controlled comparative study. Patients were administered CDZM or CTX by drip infusion b.i.d. for 14 days in principle at a daily dose of two grams. The parameters assessed were clinical efficacy, safety and clinical usefulness. The following results were obtained: 1. On the basis of committee judgement the clinical efficacy rate was 78.1% (125/160) for the CDZM group, 82.7% (124/150) for the CTX group, and no significant difference was observed between the two drug groups. On the other hand, on the basis of judgement by physicians in charge, the clinical efficacy rate was 83.1% (133/160) for the CDZM group, 83.9% (125/149) for the CTX group, and no significant difference was observed between the two groups. 2. The corresponding figures for patients with pneumonia and pulmonary suppuration were 82.4% (70/85) for the CDZM group, 79.7% (59/74) for the CTX group and no significant difference was observed according to the committee judgement. The judgement by physicians in charge also revealed 83.5% (71/85) for the CDZM group and 82.2% (60/73) for the CTX group. No significant difference was noted between the two groups. While, the committee judgement for the clinical efficacy in patients with chronic respiratory tract infections showed 73.3% (55/75) for the CDZM group, 85.5% (65/76) for the CTX group, and no significant difference was observed between the two drug groups. The corresponding figures were 82.7% (62/75) for the CDZM group, 85.5% (65/76) for the CTX group, and no significant difference was observed between the two drug groups on the judgement by physicians in charge. Furthermore, the clinical efficacy of both drugs on chronic respiratory tract infections was assessed according to "Criteria for Evaluation of Clinical Efficacy of Chemotherapeutics on Chronic Respiratory Tract Infection". It was 76.8% (53/69) for the CDZM group, 76.3% (58/76) for the CTX group, and no significant difference was observed between the two groups. 3. The bacteriological eradication rate of causative pathogens was 92.4% out of 66 patients treated with CDZM and 95.5% out of 67 patients treated with CTX in whom judgement was possible. No significant difference was observed between the two drug groups. 4. The adverse reactions occurred in 4 (2.2%) patients for the CDZM group and 8 (4.5%) patients for the CTX group respectively, with no significant inter-group difference in frequency of these reactions for all cases.(ABSTRACT TRUNCATED AT 400 WORDS)

A malignant pheochromocytoma with ileus, polyuria and hypercalcemia: a case of recurrence 17 years after the initial operation.

A case of malignant pheochromocytoma, with a recurrence 17 years after the initial diagnosis of benign pheochromocytoma, was presented. The autopsy revealed multiple metastases of pheochromocytoma to the bone marrow of the thoracic and lumbar vertebrae. Of particular note is the fact that the patient was associated with paralytic ileus, polyuria and hypercalcemia and that he died of hypercalcemia crisis. Cases like this appear to be very rare.