Enhanced cardiac clearance of iodine-123-MIBG in chronic renal failure

We studied myocardial accumulation and clearance of [123I]metaiodobenzylguanidine (MIBG) along with measurements of plasma norepinephrine concentrations.

METHODS

Myocardial imaging with MIBG and plasma norepinephrine concentration measurements were performed in 21 patients with chronic renal failure on dialysis and 11 control subjects. Dynamic acquisitions, begun immediately after MIBG injection, and planar images 15 and 150 min after injection were used to measure early and late myocardial uptake and clearance rates of MIBG from the heart.

RESULTS

Early and late MIBG uptake was not significantly different from that in controls but MIBG clearance was significantly more rapid in controls. Based on echocardiographic findings, the patients were divided into three subgroups: those without left ventricular hypertrophy and dysfunction (n = 10), with hypertrophy (n = 4) and with dysfunction (n = 7). Among controls and the three patient subgroups, MIBG clearance was significantly higher in all the subgroups and also was significantly higher in patients with dysfunction than in those without hypertrophy and dysfunction. Plasma norepinephrine levels were significantly higher in patients than in controls and correlated significantly with the clearance rate.

CONCLUSION

MIBG clearance from the heart was rapid in patients with chronic renal failure on dialysis, particularly those with left ventricular dysfunction or hypertrophy, suggesting cardiac sympathetic overactivity in these patients.

PCDD, PCDF, planar and other PCB levels in human milk in Japan. off

26 human milk samples in Japan were individually analyzed for PCDDs, planar and other PCB. Mean total concentrations of PCDDs planar and other PCBs were 8.5 pg/g, 8.8 pg/g and 5.5 ng/g of whole milk, respectively. TEQs were calculated using International-TEFs(I-TEFs) for PCDDs/Fs and TEFs proposed by the WHO for planar PCBs. Mean total TEQs of PCDDs and planar PCBs were 0.48, 0.63 and 0.39 pg/g of whole milk, respectively. These values were similar to those of other industrialized countries.

Modification of alpha-chymotrypsin using a water-soluble photo-Fenton reagent

Modification of an enzyme, alpha-chymotrypsin, was examined by using a water-soluble photo-Fenton reagent. By photoirradiation of the enzyme with the reagent, which can occupy a binding site of the enzyme, a tryptophan residue in the vicinity of the active site was oxidized to N-formylkynurenine. Concurrently, the catalytic properties of the enzyme were largely changed: the Km was increased and the kcat was decreased. The decrease in kcat for a specific amide substrate was the most significant among the esters and amides examined. The water-soluble photo-Fenton reagent would be useful to chemically modify relatively limited regions in biomolecules.

The protein tyrosine kinase Fyn activates transcription from the HIV promoter via activation of NF kappa B-like DNA-binding proteins

Protein tyrosine kinase p59fyn (Fyn) associates with the TCR-CD3 complex, which suggests that Fyn plays a significant role in the signal transduction involving TCR complex. In addition to cellular genes, viral promoters such as the HIV long terminal repeat (LTR) are also activated upon T cell activation. To elucidate the functional significance of Fyn in the expression of viral promoters, we transfected a Fyn-expression vector together with a reporter plasmid containing the chloramphenicol acetyltransferase gene driven by HIV LTR into a human T cell line, Jurkat. In this assay, Fyn stimulated the promoter in HIV LTR when the transfected cells were treated with both concanavalin A and PMA as an antigen-mimic stimulation. This activation required the intact SH2 domain of Fyn. Mutational analysis of HIV LTR showed that the NF kappa B binding sites were responsible for this effect. Electrophoretic mobility shift assays and UV cross-linking experiments showed that activation of T cells by anti-CD3 antibody induced four kappa B-binding proteins (50, 60, 65 and 100 kDa) in Fyn-overexpressing cells more efficiently than in the parental cells. Our results suggested that Fyn was able to regulate expression of a subset of genes via kappa B-binding proteins upon T cell activation.

Suppression of a nonselective cation conductance by substance P in cochlear outer hair cells

Substance P (SP) hyperpolarizes outer hair cells (OHCs) of guinea pig cochlea. The cellular mechanisms of the SP response were investigated with the whole cell patch-clamp technique. SP induced outward currents in a dose-dependent manner at a holding potential of -60 mV in a concentration range between 3 x 10(-6) and 10(-4) M. SP decreased slope conductance between -60 and +20 mV. Ion substitutions in the external medium revealed that SP suppresses nonselective cation conductance with high permeability for Ca2+. The relative ion permeability of the channel modulated by SP was as follows: Ca2+ > Li+ approximately Cs+ approximately Na+ > Tris+. The potency of the agonist action was as follows: SP >> neurokinin A > neurokinin B. Peptide antagonists induced currents similar to those of SP. CP-96345, a selective nonpeptide antagonist for the neurokinin type 1 receptor, did not inhibit the SP-induced current. Intracellular dialysis of guanosine 5'-O-(2-thiodiphosphate) and pertussis toxin (PTX) suggests that a PTX-insensitive G protein is involved in the SP response. Neither the Ca2+ chelator 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid nor staurosporine (10(-6) M) affects the SP response. Local application of SP by a puffer pipette indicates that the SP receptors are distributed along the side of the OHC. These results suggest the possibility that the action of SP on the OHCs may not be mediated by the tachykinin receptors but rather by a tachykinin receptor-independent pathway. It is proposed that SP suppresses the nonselective cation conductance in the lateral wall of OHCs via a PTX-insensitive G protein.

Beta-adrenergic stimulation induces ST-segment elevation in dogs with healing myocardial infarction

There is controversy with regard to the mechanism of the exercise-induced ST-segment elevation in myocardial infarction. The purpose of the present study was to investigate the mechanism of ST-segment elevation through pharmacologic interventions. Transmural anterior myocardial infarction was produced by gelatin sponge embolization of the left anterior descending artery in seven closed-chest dogs. One and four weeks after myocardial infarction, the dogs underwent the following three interventions: right atrial pacing, norepinephrine infusion (3.75, 7.5, and 15 micrograms/min) with the pacing, and methoxamine injection (2.5 and 5.0 mg) with the pacing. All dogs had transmural infarction with a mean infarct size of 12.0 +/- 4.2% of the left ventricular weight. Right atrial pacing did not induce significant changes in ST-segment. Norepinephrine induced a marked elevation of ST-segment at leads V1 to V4, while methoxamine did not. Norepinephrine induced a significant increase in left ventricular ejection fraction, while methoxamine produced a marked decrease in the ejection fraction and an increase in ventricular volume. The mean percent radial shortening of the non-infarct ventricular wall showed a significant increase with norepinephrine, but a decrease with methoxamine. In conclusion, myocardial ischemia and wall motion abnormality may be excluded as possible mechanisms of ST-segment elevation and an enhanced beta-adrenergic mechanism in the non-infarct myocardium is suggested to be responsible for ST-segment elevation.

Cleansing efficacy of commercial denture cleansers: ability to reduce Candida albicans biofilm activity

A simple method to measure Candidal biofilm activity using pH change of Stomastat was developed and used to evaluate the efficacy of 11 commercial denture cleansers on Candida albicans biofilm. The initial number of yeasts inoculated correlated with the pH value of Stomastat after both 24- and 30-hour incubation periods (r=0.992; r=0.988, respectively; P<.01), which supported the method's validity. The ability of the cleansing agents to decrease fungal biofilm activity varied depending upon the components of the agents. In general, peroxide denture cleansers, a disinfectant, and one enzyme cleanser were more efficacious than the other types tested in this study.

Psoriasis and hepatitis C virus

We have analyzed 8 patients (6 men and 2 women, aged 52 to 70 years) with psoriasis associated with hepatitis C virus (HCV) infection among 79 psoriatic patients. Psoriasis preceded in 6 cases. One patient had generalized pustular psoriasis (GPP), and the others had psoriasis vulgaris (PV). The psoriasis area and severity index (PASI) score ranged from 2.7 to 32.4. Two of the patients were treated with interferon-gamma. Anti-HCV antibodies were detected in all cases by second generation enzyme-linked immunosorbent and recombinant immunoblot assay. HCV messenger RNA was demonstrated by reverse transcriptase polymerase chain reaction in the tissue sections of the lesions of 1 of the patients with PV and the patient with GPP, providing evidence for active viral replication in the skin lesion. HCV-related chronic active hepatitis might cause several immunological abnormalities. It is suggested that this infection might be one of the triggering factors of psoriasis.

Inflammatory involvement of the hypophysis in Tolosa-Hunt syndrome

We report a case of painful ophthalmoplegia (Tolosa-Hunt syndrome), which was complicated with diabetes insipidus (DI) and pituitary-adrenal axis hypofunction. A 42-year-old man hospitalized for left orbital pain and impairment of left cranial nerves III, IV, V, VI, developed diabetes insipidus during the corticosteroid treatment. Neuroimaging studies disclosed a thickened, highly contrast-enhanced pituitary stalk, swollen pituitary gland and widened left cavernous sinus up to the superior orbital fissure, which were accompanied by diabetes insipidus and hypofunction of the pituitary-adrenal axis. These were indicative of an extension of granulomatous inflammation of the cavernous sinus to the pituitary portal system and the gland itself.

[Taste disturbance as an initial manifestation of Guillain-Barré syndrome in a 14-year-old girl]

We reported a 14-year-old girl who showed taste disturbance as an initial manifestation of Guillain-Barré syndrome (GBS). After an upper respiratory infection, she initially complained of taste disturbance, diplopia and salivation, followed by weakness in the legs and numbness in the extremities. On admission, she showed taste deficiency for sweet and sour sense, and a decline of salty and bitter taste. Weakness in the legs and disappearance of deep tendon reflexes were also noticed. We considered that the findings of electrophysiological examinations would conform to demyelinating features. Laboratory examinations revealed an increase of memory T cells in the peripheral blood and an elevated level of myelin basic protein in the cerebrospinal fluid. Based on clinical features and laboratory data, the diagnosis of GBS was made. We should keep taste disturbance in mind as one of the signs of GBS.

[Multiple perifollicular fibroma]

Perifollicular fibroma (PF) is a cutaneous hamartomatous proliferation of the pilar connective tissue sheath. It occurs predominantly on the face or neck in a solitary or multiple form. Histologically, it is characterized by a concentric arrangement of collagen fibers surrounding hair follicles. Other related proliferations include fibrofolliculoma and trichodiscoma, which are often complicated or have histological overlapping features, so they may represent the same spectrum of pilar mesodermal proliferation. Some individuals with multiple PFs have colonic polyposis, some of which develop into carcinomas, and there are suggestions of autosomal dominant inheritance. It appears that patients with multiple PFs and/or other connective tissue hamartomas may be at risk for colonic polyposis. Cutaneous signs may lead to an early discovery of digestive diseases.

Impaired proliferation of peripheral B cells and indication of autoimmune disease in lyn-deficient mice

The Src family protein-tyrosine kinase Lyn associates physically with the BCR and has been suggested to play an important role in BCR-mediated signaling. Studies with lyn-/- mice showed that the number of B cells decreased by half in their peripheral tissues. In addition, these B cells do not respond normally to a number of stimuli, including BCR cross-linking and CD40 ligand. Induction of tyrosine phosphorylation on a variety of cellular proteins, such as Vav, Cbl, and HS1, upon BCR cross-linking was also abolished in these B cells. Despite the impaired BCR-mediated signaling, concentrations of IgM and IgA in sera were remarkably elevated, and production of autoantibodies was detected in lyn-/- mice. Histological study showed splenomegaly and enlargement of lymph nodes that became evident with age in the mutant mice. The spleen contained significant number of plasma cells as well as unusual lymphoblast-like cells carrying Mac1 antigen and cytoplasmic IgM. These cells spontaneously secreted a large amount of IgM in vitro. Finally, significant number of lyn-/- mice show glomerulonephritis, an indication of autoimmune disease. From these data, we conclude that Lyn plays a role in signal transduction for not only clonal expansion and terminal differentiation of peripheral B cells but also elimination of autoreactive B cells.

Leukemic erythroderma with elevated plasma IL-3 and hyperhistaminemia: in situ expression of IL-3 mRNA in leukemic cells

We report a case of chronic myelogenous leukemia (CML) with pruritic erythroderma. Hyperhistaminemia, elevated level of plasma interleukin-3 (IL-3), and moderate basophilia were noted in this case. His skin manifestation was resistant to topical corticosteroid therapy and exacerbated in parallel with leukocyte count, plasma histamine and IL-3 levels. To identify localization and production of IL-3 in our case, we performed in situ hybridization on peripheral blood cells and skin biopsy specimen, and detected IL-3 mRNA in myelogenic cells in both specimens.

Effect of components of resilient denture-lining materials on the growth, acid production and colonization of Candida albicans

Variation in the components of soft lining materials, i.e. the size of polymer particles, the ethyl alcohol content of the liquids and the type of plasticizer, were investigated with respect to their effects on the growth and colonization of Candida albicans. Inhibitory effects on fungal growth and/or acid production were found to vary depending upon the components of soft lining materials. In particular, two plasticizers, benzyl benzoate (BB) and benzyl salicylate (BS), significantly decreased the growth rate, whereas the size of polymer particle had little effect on fungal growth. Ethyl alcohol content of liquid significantly affected the fungal growth and/or acid production depending upon the plasticizer used. For instance, in the case of BS, the antifungal effect was related to ethyl alcohol contents, whereas a reverse effect was observed with benzyl n-butyl phthalate (BBP). Further examination using scanning electron microscopy revealed that Candida blastospores colonized lining materials in the following two ways depending on the plasticizers used. On the BS and dibutyl phthalate (DBP) specimen, the blastospore of this yeast associated loosely, whereas, in the case of BB, BBP and butyl phthalyl butyl glycorate (BPBG), fungal blastospore tightly and invasively colonized onto the specimens. These results clearly demonstrated a relationship between components of soft lining materials and fungal growth and colonization.

[Chorea with prominent spasticity associated with an expansion of the CAG trinucleotide repeat in the IT15 gene: a case report]

A 60-year-old female, who had been noted to have slowly progressive mental changes since the age of 40, subsequently developed irregular, abrupt, jerking movements of her limbs, and coordination and walking difficulty after 15 years. Her father, aunt and sister had also been suffering from similar involuntary movements and changes of personality. Neurological examination revealed slight dementia, choreic movements and the evidence of pyramidal tract signs; i.e., she showed general hyperreflexia of extremities, bilateral ankle clonus, and extensor plantar responses of lower extremities. laboratory data were all within normal ranges except iron deficiency anemia. Axial MRI showed moderate cortical atrophy, however, without dilatation of the frontal hours of lateral ventricles and the caudate head appeared normal. Our initial impression was dentatorubropallidoluysian atrophy (DRPLA). However, the genetic analysis of her peripheral leukocytes disclosed an expansion of the CAG repeats (43 copies) in the IT15 gene in chromosome 4p, indicating the diagnosis of Huntington's disease (HD). CAG repeats in chromosome 12, known to link with DRPLA, was not expanded. Thus, this case is unique in that the classical symptomatologies of HD was betrayed by the presence of prominent pyramidal tract signs. This patient may be of importance in demonstrating the diversity of neurological symptoms and neuropathologies caused by CAG trinucleotide repeats in HD.

External radiation therapy of prostatic carcinoma and its relationship to hormonal therapy

From 1980 to 1990, a total of 54 patients with prostatic carcinoma were treated with external radiation therapy at the Kumamoto National Hospital. Ten patients were classified as Stage B, 22 as Stage C, and another 22 as Stage D according to the American Urological Association Clinical Staging System. The 5-year survival for all 54 patients was 30%. The 5-year disease-specific survival was 67% for Stage B, 47% for Stage C, and 26% for Stage D. The 5-year survival was 43% for patients in whom radiation therapy was initiated immediately after the first diagnosis or with less than one year of hormonal therapy, while it was 0% for patients in whom radiation therapy was initiated after more than one year of hormonal therapy (p = 0.01). The cause of intercurrent death was acute myocardial infarction in four patients and acute cardiac failure in one. Four of these patients received hormonal therapy for more than one year. The incidence of radiation-induced proctitis was not severe. This study suggests that long-term hormonal therapy prior to radiation therapy worsens the prognosis of patients with prostatic carcinoma.

Developmental changes in the electrophysiological properties of neonatal rat oculomotor neurons studied in vitro

The electrophysiological properties of oculomotor neurons were studied in neonatal rats aged 1-15 days. Action potentials were recorded from brainstem slices (frontal section) using the intracellular recording method at 35 degrees C. No significant age-dependent differences were detected in the resting potential (around -55 mV) and in the amplitude of the action potential (approximately 60 mV). However, the input resistance of oculomotor neurons declined with age from a mean of 60.8 M omega for rats 1-3 days old to 17.0 M omega for rats 14-15 days old. In addition, the duration of the action potential measured at the half-amplitude gradually decreased from 0.74 ms to 0.34 ms with increasing age. Increases were detected in the maximum rate of rise (from 117 V/s to 181 V/s) and the maximum rate of fall (from -67 V/s to -103 V/s) of the action potential. When long-lasting (500 ms) depolarizing current pulses were applied to oculomotor neurons, some neurons exhibited continuous repetitive discharge (i.e. tonic firing) while others showed transient discharge (phasic firing). The proportion of tonic-type neurons increased with age: the value was 9% for rats 1-5 days old, 37% for rats 6-10 days old and 54% for rats 11-15 days old. Concomitantly, the number of neurons showing a time-dependent inward rectification increased and the average maximum frequency of the discharge rose from 150 to 420 Hz, approximately, with age. Furthermore, it was found that the electrophysiological properties of oculomotor neurons of rats 14-15 days old were similar to those in adult rats. It is concluded that oculomotor neurons in neonatal rats show rapid alterations in their electrophysiological properties and that the ratio of tonic-type to phasic-type neurons changes during the early stages of development.

Purification and properties of a plant beta-D-glucuronidase form Scutellaria root

beta-D-Glucuronidase (baicalinase, GUS [EC 3.2.1.31]) activity in the crude drug, Scutellaria root, was assayed in line with the quality control standards of Kampo (Japanese Herbal) medicines. GUS was purified to homogeneity in the purification steps including DEAE-Sepharose Fast Flow and chromatofocusing used PBETM94 and Polybuffer 74. These results suggest that the Scutellaria GUS is composed of 55kDa active subunits and that the isoelectric point of this enzyme is pH 5.4. Optimal catalytic activity was found at pH 4.7 in the pH range 3.6--6.2 in 50 mM Na-citrate buffer. The purified enzyme hydrolyzed baicalin and wogonin glucuronide, but did not hydrolyze glycyrrhizin or some beta-glucosides found in other crude drugs. GUS activity in several crude drugs is also described.

The effects of selective serotonin reuptake inhibitors and their metabolites on S-mephenytoin 4'-hydroxylase activity in human liver microsomes

The inhibitory effects of four selective serotonin reuptake inhibitors (SSRIs), fluoxetine, sertraline, paroxetine and citalopram, and three metabolites (norfluoxetine, demethylcitalopram and didemethylcitalopram), on S-mephenytoin 4'-hydroxylation activities in human liver microsomes were studied. The 4'-hydroxylation of S-mephenytoin, a representative substrate toward CYP2C19, was competitively inhibited by all the SSRIs and their metabolites studied. The mean Ki values of fluoxetine, norfluoxetine, sertraline, paroxetine, citalopram, demethylcitalopram and didemethylcitalopram were 5.2, 1.1, 2.0, 7.5, 87.3, 55.8 and 7.7 microM, respectively. The findings suggest that some SSRIs and their metabolites with a low Ki value (e.g., fluoxetine, norfluoxetine) may reduce the clearance of drugs metabolized by this isoform of P450, thereby resulting in a possible drug-drug interaction, when administered simultaneously. In addition, SSRIs and their metabolites examined herein may be substrates toward CYP2C19.

Transplatin blocks voltage-dependent calcium current in isolated cochlear outer hair cells but is not ototoxic in vivo

The effects of cisplatin (cis-DDP) and transplatin (trans-DDP) on the voltage-dependent calcium current (ICa) of outer hair cells isolated from the guinea pig cochlea were compared using the whole-cell patch-clamp technique. Both cis-DDP and trans-DDP blocked ICa in a concentration-dependent manner. Trans-DDP did not show ototoxicity or nephrotoxicity in vivo. From these results, it was suggested that the effect of cis-DDP on ICa does not directly lead to cell death.

Increase of solubility of foreign proteins in Escherichia coli by coproduction of the bacterial thioredoxin

Eukaryotic proteins are frequently produced in Escherichia coli as insoluble aggregates. This is one of the barriers to studies of macromolecular structure. We have examined the effect of coproduction of the E. coli thioredoxin (Trx) or E. coli chaperones GroESL on the solubility of various foreign proteins. The solubilities of all eight vertebrate proteins examined including transcription factors and kinases were increased dramatically by coproduction of Trx. Overproduction of E. coli chaperones GroESL increased the solubilities of four out of eight proteins examined. Although the tyrosine kinase Lck that was produced as an insoluble form and solubilized by urea treatment had a very low autophosphorylating activity, Lck produced in soluble form by coproduction of Trx had an efficient activity. These results suggest that the proteins produced in soluble form by coproduction of Trx have the native protein conformation. The mechanism by which coproduction of Trx increases the solubility of the foreign proteins is discussed.

MIDA1, a protein associated with Id, regulates cell growth

We have isolated cDNA clone encoding a protein that can associate with Id, a helix-loop-helix (HLH) protein. This protein is named MIDA1 (Mouse Id Associate 1), and its predicted amino acid sequence consists of Zuotin (a putative Z-DNA binding protein in yeast) homology region and tryptophan-mediated repeats similar to c-Myb oncoprotein. MIDA1 associates with the HLH region of Id with the conserved region adjacent to eukaryotic DnaJ conserved motif within the Zuotin homology region, although it does not have any canonical HLH motif. The addition of antisense oligonucleotide of MIDA1 inhibited growth of murine erythroleukemia cells without interfering with erythroid differentiation, indicating that it regulates cell growth.

Integrin stimulation decreases tyrosine phosphorylation and activity of focal adhesion kinase in thymocytes

FAK, focal adhesion kinase, is expressed in a variety of cell types and has been suggested to transduce signals brought about by integrin-extracellular matrix (ECM) interactions. Integrin stimulation increases tyrosine phosphorylation and activity of FAK in all the cells examined to date. In contrast, in thymocytes stimulation of VLA-4 (alpha 4 beta 1) and LFA-1 (alpha L beta 2) resulted in a marked decrease in tyrosine phosphorylation and activity of FAK.

Maturation of static sensitivity is related to expansion of the capsular space in rat buccal stretch receptors

The developmental relationship between static sensitivity and structure of the buccal stretch receptor (BSR) in rats was investigated. When responses to ramp-and-hold stretches were recorded from isolated BSRs, their static sensitivities suddenly increased between 2 and 4 weeks after birth. However, no apparent change was observed throughout other developmental stages examined. Electron microscopic examination revealed a conspicuous expansion of the fluid-filled capsular space caused by completion of the outer capsule during the same postnatal period. These findings suggest that an increase in the capsular space of BSR may be involved in increasing the static sensitivity of this receptor.

Reduced cell motility and enhanced focal adhesion contact formation in cells from FAK-deficient mice

The intracellular protein tyrosine kinase FAK (focal adhesion kinase) was originally identified gy its high level of tyrosine phosphorylation in v-src-transformed cells. FAK is also highly phosphorylated during early development. In cultured cells it is localized to focal adhesion contacts and becomes phosphorylated and activated in response to integrin-mediated binding of cells to the extracellular matrix, suggesting an important role in cell adhesion and/or migration. We have generated FAK-deficient mice by gene targeting to examine the role of FAK during development. Mutant embryos displayed a general defect of mesoderm development, and cells from these embryos had reduced mobility in vitro. Surprisingly, the number of focal adhesions was increased in FAK-deficient cells, suggesting that FAK may be involved in the turnover of focal adhesion contacts during cell migration.