High-temperature ferromagnetism in CaB2C2

We report a high Curie-temperature ferromagnet, CaB2C2. Although the compound has neither transition metal nor rare earth ions, the ferromagnetic transition temperature Tc is about 770 Kelvin. Despite this high T(c), the magnitude of the ordered moment at room temperatures is on the order of 10(-4) Bohr magneton per formula unit. These properties are rather similar to those of doped divalent hexaborides, such as Ca(1-x)La(x)B6. The calculated electronic states also show similarity near the Fermi level between CaB2C2 and divalent hexaborides. However, there is an important difference: CaB2C2 crystallizes in a tetragonal structure, and there are no equivalent pockets in the energy bands for electrons and holes-in contrast with CaB6. Thus, the disputed threefold degeneracy, specific to the cubic structure, in the energy bands of divalent hexaborides turns out not to be essential for high-temperature ferromagnetism. It is the peculiar molecular orbitals near the Fermi level that appear to be crucial to the high-Tc ferromagnetism.

Electron addition spectrum in the supersymmetric t-J model with inverse-square interaction

The electron addition spectrum A+(k,omega) is obtained analytically for the one-dimensional (1D) supersymmetric t-J model with 1/r2 interaction. The result is obtained first for a small-sized system and its validity is checked against the numerical calculation. Then the general expression is found which is valid for arbitrary size of the system. The thermodynamic limit of A+(k,omega) has a simple analytic form with contributions from one spinon, one holon, and one antiholon-all of which obey fractional statistics. The upper edge of A+(k,omega) in the (k,omega) plane includes a delta-function peak which reduces to that of the single-electron band in the low-density limit.

Slow switching in globally coupled oscillators: robustness and occurrence through delayed coupling

The phenomenon of slow switching in populations of globally coupled oscillators is discussed. This characteristic collective dynamics, which was first discovered in a particular class of the phase oscillator model, is a result of the formation of a heteroclinic loop connecting a pair of clustered states of the population. We argue that the same behavior can arise in a wider class of oscillator models with the amplitude degree of freedom. We also argue how such heteroclinic loops arise inevitably and persist robustly in a homogeneous population of globally coupled oscillators. Although a heteroclinic loop might seem to arise only exceptionally, we find that it appears rather easily by introducing time delay into a population which would otherwise exhibit perfect phase synchrony. We argue that the appearance of the heteroclinic loop induced by the delayed coupling is then characterized by transcritical and saddle-node bifurcations. Slow switching arises when a system with a heteroclinic loop is weakly perturbed. This will be demonstrated with a vector model by applying weak noises. Other types of weak symmetry-breaking perturbations can also cause slow switching.

Strong desynchronizing effects of weak noise in globally coupled systems

In assemblies of globally coupled dynamical units, weak noise perturbing independently the individual units can cause anomalous dispersion in the synchronized cloud of the units in the phase space. When the noise-free dynamics of the synchronized assembly is nonperiodic, various moments of the linear dimension of the cloud as a function of the noise strength exhibit multiscaling properties with parameter-dependent scaling exponents. Some numerical evidence of this peculiar behavior as well as its interpretation in terms of a multiplicative stochastic process with small additive noise is provided. Universality of the phenomenon is also discussed.

Identification and characterization of a novel follistatin-like protein as a binding protein for the TGF-beta family

Follistatin is an activin-binding protein that prevents activin from binding to its receptors and neutralizes its activity. Follistatin also binds bone morphogenetic proteins (BMPs). In this study, we report the identification of a novel follistatin-like protein from mouse. The mouse cDNA encodes a 256-residue precursor and most likely a mouse homologue of human FLRG, which was found at the breakpoint of the chromosomal rearrangement in a B-cell line. Whereas follistatin has three follistatin domains, which are presumed to be growth factor binding motifs, FLRG possesses only two follistatin domains. Northern blotting revealed that mRNAs for FLRG were abundantly expressed in heart, lung, kidney, and testis in mouse. The recombinant mouse FLRG proteins were found to have binding activity for both activin and bone morphogenetic protein-2. Like follistatin, FLRG has higher affinity for activin than for BMP-2. The FLRG protein inhibited activin-induced and BMP-2-induced transcriptional responses in a dose-dependent manner. Glutathione S-transferase fusion proteins encoding various regions of FLRG were produced and studied. Ligand blotting using (125)I-activin revealed that the COOH-terminal region containing the second follistatin domain was able to bind activin. Our finding implies that cellular signaling by activin and BMPs is tightly regulated by multiple members of the follistatin family.

Exact dynamical structure factor of the degenerate haldane-shastry model

The dynamical structure factor S(q,omega) of the K-component ( K = 2, 3, 4) spin chain with a 1/r(2) interaction is derived exactly at zero temperature for the arbitrary size of the system. The result is interpreted in terms of a free quasiparticle picture which is a generalization of the spinon picture in the SU(2) case. The excited states consist of K quasiparticles each of which is characterized by a set of K-1 quantum numbers. Divergent singularities of S(q,omega) at the spectral edges are derived analytically. The analytic result is checked numerically for finite systems.

A case of neuroleptic-induced unilateral akathisia with periodic limb movements in the opposite side during sleep

We report on a patient with schizoaffective disorder who developed unilateral akathisia. This is the first case report of a patient with neuroleptic-induced unilateral akathisia on whom an all-night polysomnogram was recorded. On the polysomnogram we observed right side periodic limb movements (PLM) with left side unilateral akathisia, and after her akathisia disappeared, the PLM also disappeared. Brain MRI findings and neurological findings were within normal limits. The pathogenetic lesion causing akathisia could not be elucidated.

[Recent progress in akathisia]

Neuroleptic-induced akathisia should be definitely diagnosed as acute, tardive, withdrawal, and chronic. The diagnostic assessment must be identified from the subjective report and objective features. Various assessments of measuring akathisia can be clinically used by instrumental methods and rating scales. The pharmacological basis of neuroleptic-induced akathisia is the inhibition of the dopamine receptors in the brain. The pathogenesis of neuroleptic-induced akathisia may involve GABAergic hypoactivity, noradrenergic hyperactivity, and serotonergic dysfunction in CNS. Iron deficiency and hyperglycemia may be risk factors of neuroleptic induced akathisia in relation to the dopamine function in the brain. Neurological disorders may be associated with the development of a syndrome resembling drug-induced akathisia. The lesion of the thalamic nuclei would originally produce the syndrome. The difference between acute and tardive akathisia on the strategy of the drug treatment should be sufficiently comprehended. In particular, the long-term use of anticholinergic drugs and benzodiazepines should not be prevailed.

Nocturnal eating/drinking syndrome and neuroleptic-induced restless legs syndrome

Nocturnal eating/drinking syndrome secondary to neuroleptic-induced restless legs syndrome (RLS) occurred under treatment with low-dose haloperidol in a 51-year-old female schizophrenic patient. Polysomnographic investigation showed a low level of sleep efficacy, periodic leg movements, and a strict relationship between nocturnal eating episodes and non-rapid eye movement sleep. Her nocturnal eating and RLS were completely inhibited by clonazepam treatment. To our knowledge, this is the first published case of nocturnal eating/drinking syndrome secondary to neuroleptic-induced RLS.

Generation of 0.66-TW pulses at 1 kHz by a Ti:sapphire laser

A 1-kHz, 0.66-TW Ti:sapphire laser has been developed. We obtained 21-fs, 14-mJ pulses with an extraction efficiency of 32% in the final amplifier. The dispersion through the system was successfully compensated for by insertion of a pair of prisms in a regenerative amplifier. The pulses were characterized by frequency-resolved optical gating and were in good agreement with dispersion calculated by three-dimensional ray tracing.

High-power sub-100-fs UV pulse generation from a spectrally controlled KrF laser

High-power sub-100-fs UV pulses were generated from a KrF excimer laser by spectral control and chirped-pulse amplification. The spectral width was broadened to 1.6 nm, resulting in 72-fs, nearly transform-limited pulses. The average output powers at 1 kHz were 0.6 and 1.2 W for pulse widths of 72 and 110 fs, respectively.

Dietary fibers modulate indices of intestinal immune function in rats

To explore the immunological roles of dietary fiber, male 4-wk-old Sprague-Dawley rats were fed for 2 wk cellulose (water-insoluble), konjak mannan (water-soluble), pectin (water-soluble) or chitosan (acid-soluble) at 5 g/100 g diet. Serum IgE concentrations in rats fed konjak mannan, pectin and chitosan were significantly lower than in those fed cellulose (mean +/- SEM: 5.0 +/- 1.1, 3.6 +/- 1.3, 3.0 +/- 1.2 and 9.6 +/- 1.9 microg/L, respectively). Rats fed pectin had significantly higher serum IgA and IgG concentrations (358 +/- 38 and 424 +/- 36 mg/L for IgA and IgG, respectively) than those fed cellulose (240 +/- 31 and 337 +/- 25 mg/L) or chitosan (176 +/- 22 and 379 +/- 23 mg/L), while the IgM concentration did not differ among the groups. Concentrations of IgA, IgG and IgM in mesenteric lymph node (MLN) lymphocytes generally were greater, while IgE concentration was lower, in rats fed pectin and chitosan than in those fed cellulose. The proportion of CD4+ T-cells in MLN lymphocytes was also dietary fiber-dependent, and the CD4+/CD8+ ratio was significantly higher in the pectin fed group than in all other groups. Under certain experimental conditions, MLN lymphocytes from rats fed pectin had markedly greater interferon-gamma concentration than cells from other groups, while the effect on tumor necrosis factor-alpha concentration was less marked. Thus, dietary fiber may have an immunoregulatory effect on the intestinal immune system of rats.

Stimulating effect of xanthene dyes on immunoglobulin produced in vitro by rat spleen lymphocytes

The effects of food additives on immunoglobulin produced in rat splenic lymphocytes were examined. The xanthene dye, Rose Bengal, enhanced IgE production, while inhibiting the production of IgG and IgM, at 50 microM. Among the xanthene dyes, Rose Bengal having 4 iodine and 4 chlorine atoms exerted the highest Ig production-regulating activity in splenocytes, and dihalogenated fluorescein, a diiodo compound, exerted similar activity, while the dichloro and dibromo compounds did not. These results suggest that halogen atoms, especially the iodine atom, in xanthene dyes play an important role in regulation of Ig production.

Effect of natural food colorings on immunoglobulin production in vitro by rat spleen lymphocytes

Water-soluble (cacao pigment, cochineal pigment, corn pigment, betanin, carthamus yellow, and monascus pigment) and water-insoluble (gardenia yellow, laccaic acid, bixin, and curcumin) natural colorings inhibited IgE production by rat spleen lymphocytes at 10 and microM, respectively. Although many of these colorings only inhibited the production of IgG and IgM at high concentrations, the water-insoluble colorings enhanced IgM production even at 1 microM. These results suggest that natural colorings have immunoglobulin production-regulating activity.

Solitary mastocytoma with massive eosinophilic infiltration

An 11-month-old girl had a yellowish brown nodule that histologically had an unexpectedly massive infiltrate of eosinophils in the dermis. This histologic feature made determining the correct diagnosis of cutaneous solitary mastocytoma difficult until we performed specific histochemical staining for mast cells.

Psychiatric liaison issues in cancer care in Japan

To clarify the psychiatric liaison issues in Japan, this paper briefly introduces a survey of physician attitudes and practices regarding cancer care in Japan and preliminarily reports on an "active" liaison program developed at one Japanese general hospital. The survey of physicians from 31 teaching hospitals, including all cancer centers, revealed that 56% of physicians do not inform patients of a diagnosis of cancer. Thus, actual psychiatric consultation referrals were very few due to the physician's fear of harming his relationship with the cancer patient. One medical unit, in which about one-quarter of the cancer patients were told their diagnoses by the unit chief physician, showed significantly higher rates of psychiatric consultation after the introduction of an "active" liaison program in that hospital. These results suggest that the liaison program can positively influence the rate of psychiatric consultation referrals for cancer patients when the physician discloses the diagnosis to the patient. Consultation-liaison psychiatry in cancer care is expected to develop in Japan, because most physicians report a trend toward informing patients of their cancer diagnosis.

Histoanalytical study of the cellular infiltrate in the tuberculin reaction

In contrast to the generally held view, in previous studies it has been found that the histopathological changes in delayed-type hypersensitivity reactions to intradermal purified protein derivative of tuberculin (PPD) in humans were not uniform. These were classified into three types based on their resemblance to features seen in other dermatoses, i.e.: (i) perivascular dermatitis type; (ii) basal spongiotic dermatitis type; and (iii) erythema multiforme type. These histopathological patterns correlated well with the clinical response seen in tuberculin hypersensitivity of tested subjects. In the present study, the immunohistopathological features in 44 skin biopsy specimens were assessed quantitatively by using multivariate analysis. The numbers of infiltrating cells in the epidermis and in the dermis which were immunohistologically positive to monoclonal antibodies against various mononuclear cells were counted separately to determine if there was any statistical correlation between the histopathological patterns and the phenotypes of infiltrating cells. As a result, a significant correlation was found between the histopathological patterns and the phenotypes of cells infiltrating the epidermis, such as CD8+ cells, CD4+ cells, CD11c+ cells and interleukin 2 receptor positive cells. All these cells showed a high correlation coefficient to the expression of HLA-DR antigen by keratinocytes. Next, factors that might regulate the inflammation and interaction among the infiltrating cells were assessed.(ABSTRACT TRUNCATED AT 250 WORDS)

A model for feature linking via collective oscillations in the primary visual cortex

A neural network model for explaining experimentally observed neuronal responses in cat primary visual cortex is proposed. In our model, the basic functional unit is an orientation column which is represented by a large homogeneous population of neurons modeled as integrate-and-fire type excitable elements. The orientation column exhibits spontaneous collective oscillations in activity in response to suitable visual stimuli. Such oscillations are caused by mutual synchronization among the neurons within the column. Numerical simulation for various stimulus patterns shows that as a result of activity correlations between different columns, the amplitude and the phase of the oscillation in each column depend strongly on the global feature of the stimulus pattern. These results satisfactorily account for experimental observations.

Acquired zinc deficiency in breast-fed infants

Zinc deficiency in breast-fed infants is a rare disease caused by a low level of zinc in their mother's milk. Premature infants are more vulnerable to develop zinc deficiency than full-term infants because, despite their high zinc requirements, they have insufficient body stores of zinc and a poor capability to absorb zinc from the gut. The clinical aspect of zinc deficiency is acrodermatitis enteropathica, in which the severity is proportional to the zinc level. The patients respond well to oral zinc supplements.

Generalized eruptive histiocytoma: a report of a variant case showing the presence of dermal indeterminate cells

We describe a 14-year-old Japanese girl with a variant of generalized eruptive histiocytoma. She presented with the characteristic features of classical generalized eruptive histiocytoma but with the following minor differences. Clinically, some of the papular eruptions tended to coalesce to form plaques. Histoligically, some of the histiocytic cells were S-100 protein- and OKT-6-positive; these were thought to be indeterminate cells because they lacked Birbeck granules. In addition, PAS-positive cells were few and there were some intermingled lymphocytes and a few eosinophils.

Tyrosinemia II: report of an incomplete case and studies on the hyperkeratotic stratum corneum

We report a case of tyrosinemia II in a 20-year-old man who had painful palmoplantar hyperkeratotic lesions and corneal erosion. His serum tyrosine level was more than 10 times above normal. Though dietary control failed to eliminate the skin lesions, etretinate cleared them temporarily and grafted skin from the buttock did not become hyperkeratotic during the observation period of 1 1/2 years. Amino acid analysis in the hyperkeratotic stratum corneum disclosed a moderate increase not only in soluble tyrosine but also in other amino acid contents. Turnover time of the hyperkeratotic stratum corneum was greatly elongated as compared with that of the grafted site.

Erythema induratum of Bazin as a type of tuberculid

We report three cases of patients with erythema induratum of Bazin who showed extreme tuberculin hypersensitivity reactions and a good therapeutic response to isoniazid. In the first patient satellite lesions with epithelioid granuloma formation developed 3 weeks after injection of purified protein derivative. In the second patient a high fever developed 1 day after injection of purified protein derivative, and the third patient blistered at the injection site; the histopathologic pattern was similar to erythema multiforme. Immunohistologic study of the epithelioid granulomas demonstrated a predominance of Leu-1--bearing, Leu-3a--bearing, and human lymphocyte antigen-DR-expressing cells. We conclude that erythema induratum of Bazin represents a tuberculid caused by heightened delayed-type hypersensitivity to components of tubercle bacilli released from latent foci of infection.

Primary adenoid cystic carcinoma masquerading as syringoma of the scalp

We report a case of primary adenoid cystic carcinoma of the scalp in a 72-year-old man. It consisted of syringomalike papules scattered on an erythematous plaque that showed a loss of hair. Histologically, the papular lesion at first showed numerous tadpole-like tubular structures similar to those found in syringoma. Subsequent histologic studies over 2 years revealed the presence of numerous cribriform tumor masses penetrating into the subcutis, reaching the galea aponeurotica. Immunohistochemically, the neoplastic cells showed no staining with either polyclonal (P) or monoclonal (M) antibodies to carcinoembryonic antigen. M-cytokeratin, M-vimentin, and P-S-100 protein antibodies were positive only focally as were other antibodies, including anti-actin, anti-human lactalbumin, anti-beta 2 microglobulin, and breast cancer--associated antigens. The neoplastic cells showed no binding to lectins that characteristically react with the sweat apparatus, except for concanavalin A (con A) and peanut agglutinin (PNA), although the striking histopathologic resemblance to syringoma suggested its histogenic relation to eccrine glands initially.

Chronic vulvar purpura

We described a 56-year-old Japanese woman with a long-standing asymptomatic vulvar purpuric lesion. Histological studies revealed massive hemorrhage, deposition of hemosiderin and a moderate lymphohistiocytic infiltration. We speculate that chronic intrapelvic congestion with increased venous pressure possibly due to abdominal ptosis played an important role in the pathomechanism for this persistent purpuric lesion of the vulva.

Histopathologic pattern analysis of human intracutaneous tuberculin reaction

The involvement of cellular immune reactions in the pathogenesis of many inflammatory dermatoses can be postulated from their histopathologic features, e.g., those dermatoses that show a perivascular lymphohistiocytic infiltration in the dermis in addition to their own characteristic epidermal changes. Several granulomatous dermatoses further show an additional infiltration of epithelioid cells. However, experimental production of similar changes is usually not feasible in animals. A human model is needed of delayed-hypersensitivity skin reaction induced by a definite antigen. After closely observing the histopathologic changes of the skin reactions to the purified protein derivative (PPD) of tuberculin, we noted that all patients did not show uniform histologic patterns at intradermal PPD injection sites. Therefore, we have tentatively analyzed histopathologically the pattern of tuberculin skin reactions at injection sites 48 h to 1 year after injection in eight healthy volunteers and 63 patients with various dermatoses. We classified the reactions at 48 h into three types, based on the extent of the tissue damage (i.e., their resemblance to features noted in corresponding inflammatory dermatoses): (a) the perivascular dermatitis type, (b) the basal spongiotic dermatitis type, and (c) the erythema multiforme type. There was a clear correlation between the magnitude of macroscopic skin reactions and these histopathologic patterns. Even those with clinically negative reactions showed a reaction pattern of perivascular dermatitis, whereas those who clinically developed prominent inflammatory reactions with blister formation always showed a erythema multiforme-like histologic pattern. Interestingly, in more than half of the cases, the dermal cellular infiltrate had a mixture of various numbers of neutrophils in addition to mononuclear cells.(ABSTRACT TRUNCATED AT 250 WORDS)

[Ultrasonic evaluation of two cases of primary lymphoma of the intestine]

Two cases of primary malignant lymphoma of the intestine were examined by ultrasonography. In the first case, the lymphoma originated from the terminal ileum and caused intussusception. The tumor was significantly hypoechoic. In the second case, the tumor showed pseudokidney sign. The echo level of the tumor was low and the size of the tumor was over 10 cm.

Multicentric reticulohistiocytosis in a child with sclerosing lesion of the leg. Immunohistopathologic studies and therapeutic trial with systemic cyclosporine

Multicentric reticulohistiocytosis affecting a 13-year-old boy induced a sclerosing change of the leg. The cellular infiltrate comprising activated T lymphocytes and macrophages and human lymphocyte antigen (HLA)-DR expression by keratinocytes in lesional skin all suggest the involvement of cellular immune reactions. We administered systemic cyclosporine but could not obtain a favorable effect without a concomitant low dosage of prednisone.

Subcutaneous sarcoidosis with extensive caseation necrosis

We report a 24-year-old male patient with sarcoidosis who developed subcutaneous nodules on his thighs and buttocks at the sites of repeated intramuscular injections. Histologically, there were extensive areas of caseation necrosis surrounded by typical sarcoidal granuloma. The nodules regressed spontaneously over a period of 4 months, concurrently, both his bilateral hilar adenopathy and the results of immunological tests, returned to normal. We think that these lesions developed at the sites of subcutaneous scar tissue induced by frequent injections in childhood. We believe the pathomechanism to be similar to that for scar sarcoidosis, and that the extensive caseation necrosis reflected a regressing stage of the disease.