Thyrotropin-releasing hormone: evidence for thyroid response to intravenous injection in man.

Administration of thyrotropin-releasing hormone to normal subjects causes a prompt rise in plasma thyrotropin concentration, followed by a significant increase in circulating plasma triiodothyronine. These observations may prove to be of value in simultaneously assessing the ability of the pituitary and thyroid glands to respond to their trophic hormones.

Scoring of reflux symptoms associated with scleroderma and the usefulness of rabeprazole.

OBJECTIVE: The high frequency of gastroesophageal reflux disease (GERD) as a complication of scleroderma (systemic sclerosis, SSc) calls for treatment with powerful acid suppressants such as proton pump inhibitors (PPI). The present study used a GERD-specific questionnaire to assess the symptoms of GERD in SSc patients, and examine the effectiveness of rabeprazole (RPZ) for treating the symptoms of GERD. METHODS: The Frequency Scale for the Symptoms of GERD (FSSG), a medical questionnaire developed in Japan for evaluating GERD, and the Visual Analogue Scale (VAS) were used to evaluate GERD symptoms and the degree of pain, respectively, in 151 SSc subjects. These tools were also used to assess the effect of 8 weeks' treatment with the PPI RPZ (10 mg/day). RESULTS: Data on age and gender, and FSSG and VAS scores before treatment and after 4 and 8 weeks' RPZ treatment, were available for 84 subjects. The mean FSSG score was 13.9+/-9.7 before treatment, 8.3+/-8.1 after 4 weeks of treatment, and 7.0+/-7.0 after 8 weeks of treatment; the score reduction was significant (p<0.001) indicating the effectiveness of RPZ in improving subjective GERD symptoms. The VAS scores revealed a significant improvement in pain after both 4 and 8 weeks compared with baseline scores. Six subjects experienced adverse effects and five discontinued the analysis during the period. CONCLUSION: Administration of RPZ 10 mg/day is effective for the control of the symptoms of GERD associated with SSc. In addition to assessing the symptoms of GERD, the FSSG questionnaire can be used to evaluate the therapeutic effect of drugs.

Modulation of pituitary responsiveness to thyrotropin-releasing hormone by triiodothyronine.

The relative roles of triiodothyronine (T(3)) and thyroxine (T(4)) in modulating pituitary responsiveness to thyrotropin-releasing hormone (TRH) have been assessed. (a) 10 hyperthyroid patients with elevated serum T(2) and T(4) levels showed no pituitary response to TRH. After 2 wk of propylthiouracil therapy T(4) levels had fallen to normal in only five patients while T(2) levels were normal in all. Pituitary responsiveness to TRH returned in all patients with normal or high T(4) concentrations. (b) Patients with isolated elevations of serum T(3) (T(3) toxicosis) failed to respond to TRH. TRH responsiveness was restored when T(3) levels fell to normal after propylthiouracil therapy. (c) When pituitary responsiveness to TRH was tested 60 min after a single oral dose of 50 mug of T(3), which increased serum T(3) levels to slightly above the normal range, no rise in thyrotropin (TSH) was seen in six subjects. These findings indicate that T(3) elevations alone can rapidly inhibit pituitary responsiveness to TRH.

Serum triiodothyronine: measurements in human serum by radioimmunoassay with corroboration by gas-liquid chromatography.

Serum triiodothyronine (T(3)) has been measured by radioimmunoassay and corroborated by analysis of the identical samples with a previously described gas-liquid chromatographic technique. Special features of the radioimmunoassay procedure which permit determinations in unextracted serum include the use of a T(3)-free serum preparation for the construction of the standard curve and of tetrachlorothyronine to inhibit binding of T(3) to thyroxine-binding globulin.T(3) values by radioimmunoassay were 138 +/-23 ng/100 ml (mean +/-SD) in 82 normal subjects, 62 +/-9 ng/100 ml in 45 hypothyroid patients, and 494 +/-265 ng/100 ml in 60 patients with toxic diffuse goiter. In the hypothyroid group, the range was similar in patients with both primary and secondary hypothyroidism. There was no overlap between the three thyroidal states. Elevated T(3) levels were seen in 40 cases that appeared clinically hyperthyroid but had normal serum thyroxine (T(3)) determinations, a syndrome we have called T(3) toxicosis. Values obtained with radioimmunoassay agreed closely with those we had previously found by gas-liquid chromatography which were 68 +/-2 ng/100 ml in hypothyroidism, 137 +/-23 ng/100 ml in normal subjects, and 510 +/-131 ng/100 ml in untreated toxic diffuse goiter. Since T(3) is very potent and its level varies in different clinical states, accurate T(3) measurements are required to assess a patient's thyroid status properly. The radioimmunoassay for T(3) appears to be sufficiently sensitive, precise, and simple to permit its routine clinical application for this purpose.

Tumor promoter 12-O-tetradecanoylphorbol 13-acetate: effect on complement and Epstein-Barr virus receptors in human lymphoblastoid cell lines.

The effect of the tumor promoter 12-O-tetradecanoylphorbol 13-acetate (TPA) on the C3 and Epstein-Barr virus (EBV) receptors in various human lymphoblastoid cells was investigated with the use of the erythrocyte-antibody-complement (EAC) rosette formation method and a quantitative bioassay for EBV receptors. TPA caused a significant decrease of C3 receptors in the cultures of both Raji and SB4 cells (by approximately 50% of the C3 receptors in untreated cultures at 10 ng/ml). Kinetic studies revealed that the rate of reduction was rather moderate but progressive, reaching a maximum 5 days after treatment with TPA. Kinetic studies showed that EBV receptors also decreased, similar to the reduction seen with C3 receptors after TPA treatment. The effect of TPA on the reduction of C3 receptors was observed not only in these cells but also in other EBV-positive B-cells, subclones of SB4 cells, and MOLT-4 cells. However, in an EBV-negative B-cell line, BJAB, EAC rosette formation was significantly enhanced.

Mutations in the peripheral myelin protein zero and connexin32 genes detected by non-isotopic RNase cleavage assay and their phenotypes in Japanese patients with Charcot-Marie-Tooth disease.

Mutations of myelin protein zero (MPZ) and connexin32 (Cx32) genes were examined in 70 unrelated Japanese patients with Charcot-Marie-Tooth disease (CMT) without PMP22 gene duplication. A new method, which could detect base pair mismatches with Rnase cleavage on agarose gel electrophoresis, identified 5 and 4 mutations of the MPZ and Cx32 genes, respectively, including one novel mutation (Ser128Ter) of Cx32. This non-isotopic RNase cleavage assay (NIRCA) employed in the present study is very suitable for exploring mutations of MPZ and Cx32 genes in a large number of CMT patients, as the phenotype of patients with CMT is greatly divergent from demyelinating to axonal pathology.

Pituitary resistance to thyroid hormone associated with a base mutation in the hormone-binding domain of the human 3,5,3'-triiodothyronine receptor-beta.

Point mutations in the human T3 receptor-beta (TR beta) gene causing single amino acid substitutions have been identified in several different kindreds with generalized resistance to thyroid hormone. Until now, no study has been reported on the TR gene in cases of pituitary resistance (PRTH). In the present study, we analyzed the TR beta gene in a 30-yr-old Japanese female with PRTH. She exhibited clinical features of hyperthyroidism, elevated serum thyroid hormone levels accompanied by inappropriately increased secretion of TSH, mildly elevated basal metabolic rate, and increased urinary excretion of hydroxyproline. No pituitary tumor was detected. DNA fragments of exons 3-8 of the genomic TR beta gene were generated by the polymerase chain reaction and analyzed by a single stranded conformation polymorphism method. Exon 7 of the patient's TR beta gene showed an abnormal band, suggesting the existence of mutation(s). By subcloning and sequencing the DNA, a point mutation was identified in one allele at nucleotide 1297 (C to T), which altered the 333rd amino acid, arginine, to tryptophan. Neither of her apparently normal parents had any mutations of the TR beta gene. In vitro translation products of the mutant TR beta gene showed remarkably decreased T3-binding activity (Ka, 2.1 x 10(8) M-1; normal TR beta Ka, 1.1 x 10(10) M-1). Since the molecular defect detected in a patient with PRTH is similar to that seen in subjects with generalized resistance to thyroid hormone, both types of the syndrome may represent a continuous spectrum of the same etiological defect with variable tissue resistance to thyroid hormone.

Increase in plasma thyrotropin-releasing hormone in normal human pregnancy.

Maternal thyroid regulation in pregnancy was examined by measuring the concentrations of TRH, T4, T3, free T4 (by RIA), T4-binding globulin, TSH, PRL, and hCG in the sera of 30 normal pregnant women, 10 puerperally lactating women, and 10 normal pregnant women, 10 puerperally lactating women, and 10 normal nonpregnant female controls. Results showed that serum T4, T3, T4-binding globulin, PRL, and hCG, but not free T4 (by RIA), increased significantly during pregnancy. The plasma level of TRH was significantly higher (P less than 0.01) in the second trimester and significantly lower (P less than 0.05 1 month post partum than those values in nonpregnant controls. No significant correlations, however, were observed between the serum level of TRH and those of the thyroid hormones TSH, PRL, and hCG in pregnancy. The TRH-degrading activity of the plasma in the second trimester was normal. These results indicate that TRH secretion may be increased in the second trimester of pregnancy.

Geometric response to nerve growth factor is preserved in aged rat sensory neurons: a single-neuron culture study.

We previously established a single-neuron culture system to analyze the primary effects of neurotrophic factors and reported that NGF promoted neurite extension in young adult (4- to 6-month-old) rat dorsal root ganglion (DRG) neurons by promoting neurite arborization. In this study, we demonstrated that the effects of NGF on neurite regeneration in DRG neurons was well preserved in aged rats (20- to 24-month-old and 33-month-old). NGF did not increase the percent process-bearing neurons in aged rats, which indicated that neuronal survival was not promoted by NGF, but it significantly enhanced the number of branching points, total neurite length, and soma size in aged neurons. These effects of NGF on neurite geometry tended to be reduced to some extent in aged neurons and the initiation of neurite-outgrowth in aged neurons was also delayed as compared with young adult neurons. NGF-responsive subpopulation of neurons, found in the entire range of neuronal size, were preserved in aged rats. These findings indicate that NGF could play an important role in regeneration of injured DRG neurons of aged animals.

Size-dependent myelinated fiber loss in the corticospinal tract in Shy-Drager syndrome and amyotrophic lateral sclerosis.

Morphometric evaluation was performed on myelinated fibers of the corticospinal tract at the seventh thoracic spinal cord segment from three patients with Shy-Drager syndrome (SDS), six patients with amyotrophic lateral sclerosis (ALS), and five patients with nonneurologic symptoms. In SDS, small-sized myelinated fibers were nearly completely depleted, while large-sized myelinated fibers were considerably well preserved. In ALS, on the contrary, large myelinated fibers were predominantly decreased. These results suggested that selective vulnerability of axonal loss depends on fiber size and should be considered in interpretation of pathology of corticospinal tracts.

Nerve growth factor receptor immunoreactivity in the neuronal perikarya of human sensory and sympathetic nerve ganglia.

We examined immunohistochemically the dorsal root ganglia, sympathetic ganglia, spinal cord, ventral and dorsal roots, and sciatic nerves obtained at autopsy from adult humans, using a monoclonal antibody against the human nerve growth factor receptor. We observed labelling in a granular pattern in the neuronal perikarya of dorsal root and sympathetic nerve ganglia. Ventral horn cells and axons were not labelled.

Segmental anhidrosis in the spinal dermatomes in Sjögren's syndrome-associated neuropathy.

We describe two women with primary Sjögren's syndrome and sensory neuropathy who had anhidrosis segmentally along the dermatomes of the spinal segment, along with sensory loss. Intradermal administration of cholinergic agents elicited no sweat response in the spinal segments with anhidrosis, whereas a normal response was present in the segments with obvious sweating. These features suggest segmental involvement of the postganglionic sympathetic ganglion cells.

Skin sympathetic nerve activity in acquired idiopathic generalized anhidrosis.

We recorded skin sympathetic nerve activity (SSNA) microneurographically from the right tibial nerve of a patient with acquired idiopathic generalized anhidrosis (AIGA). The patient did not show any spontaneous sweating or pilocarpine- and nicotine-induced sweat response. Histopathologic examination showed degenerated eccrine glands associated with surrounding inflammatory cellular infiltration. Electrical nerve stimulation produced a two-peak pattern of SSNA reflex discharge representing sudomotor and vasoconstrictor components. The frequency of spontaneous SSNA bursts (burst rate), presumably of a sudomotor nature, at the ambient temperature of 25 degrees C was significantly higher than in a healthy control subject and was further increased at a temperature of over 38 degrees C. Thus, sudomotor sympathetic nerve activity is well preserved or even increased in AIGA. We conclude that anhidrosis of AIGA results from the generalized sweat gland dysfunction rather than decreased sympathetic outflow to the skin.

Selective loss of small myelinated fibers in the lateral corticospinal tract due to midbrain infarction.

Small myelinated fibers in the lateral corticospinal tract (LCST) were selectively diminished as compared with large myelinated fibers in a patient with an old paramedian midbrain infarct involving the red nuclei, oculomotor nuclei, and inferior olivary pseudohypertrophy. Although the physiologic function of small myelinated fibers in the LCST is unknown in humans, we hypothesize that some of these fibers may include the rubrospinal tract.

Axonal pathology in Japanese Guillain-Barré syndrome: a study of 15 autopsied cases.

We assessed the frequency and extent of axonal involvement in the ventral spinal roots in 15 Japanese autopsied patients with Guillain-Barré syndrome (GBS). Teased-fiber preparation revealed that five had predominantly axonal pathology with minimal segmental demyelination, seven had predominantly segmental demyelination with minimal axonal changes, two patients showed a mixture of both conditions, and one patient did not show any particular pathologic changes. We confirmed axon loss by immunohistochemical analysis of high-molecular-weight neurofilament protein. Macrophage invasion was a prominent feature in nerves with predominantly axonal changes. Two patients with severe axonal involvement and prolonged clinical courses exhibited motor neuron loss with astrogliosis in the ventral horns. These results suggest that autopsy-verified axonal involvement is more frequent among Japanese GBS patients than in Caucasian populations but less frequent than that reported from northern China.

Nerve growth factor maintains regulation of intracellular calcium in neonatal sympathetic neurons but not in mature or aged neurons.

We examined the effects of nerve growth factor on the regulation of intracellular calcium levels of superior cervical ganglion neurons in terms of postnatal maturation and ageing. Rat superior cervical ganglion neurons from three age groups (neonatal: 0 to one-day-old, young adult: three to six-month-old, and aged: more than 24-month-old) were dissociated and cultured in the presence or absence of 100 ng/ml of nerve growth factor. Intracellular free calcium levels ([Ca2+]i) were measured using the fura-2 microfluorometry. Nerve growth factor treatment increased the resting [Ca2+]i of neonatal neurons, although it had no effect on those of mature and aged neurons. We further examined the effects of nerve growth factor on the transient increase of [Ca2+]i induced by methacholine (0.1 mM), caffeine (20 mM) or high-potassium medium (40 mM K+). Nerve growth factor pre-treatment significantly increased the population of neonatal superior cervical ganglion neurons which responded to methacholine, whereas almost all young adult and aged neurons responded to methacholine regardless of pre-treatment of nerve growth factor. Caffeine induced a cyclic alteration of [Ca2+]i (oscillation) in 45% of the neonatal superior cervical ganglion neurons when they were maintained without nerve growth factor, but nerve growth factor treatment suppressed the oscillation to 10% of neurons. In contrast to neonatal neurons, all of the young adult and aged neurons showed only a transient increase of [Ca2+]i in response to caffeine independent of nerve growth factor treatment. There was no significant effect of nerve growth factor on K+ depolarization-induced [Ca2+]i elevations at any of the ages studied. Nerve growth factor did not substantially alter the pattern of the transients induced by these three agents. Our results indicate that exogenous nerve growth factor is necessary to maintain normal acetylcholine receptor-mediated [Ca2+]i responses as well as Ca(2+)-induced Ca2+ release from intracellular calcium storage in neonatal superior cervical ganglion neurons. In mature superior cervical ganglion neurons, Ca2+ homeostasis becomes independent of exogenous nerve growth factor, and Ca2+ homeostasis and its independency are well preserved in aged neurons.

Concentrations of thyrotropin-releasing hormone and substance P are increased in several areas of the central nervous system of shambling mutant mice.

The concentrations of thyrotropin-releasing hormone (TRH) and substance P (SP) in the brain of shambling mouse, a mutant mouse which is neurologically defective showing trunk instability and hind limb incoordination, were measured by radioimmunoassay. The TRH concentrations were significantly higher in the pons, medulla oblongata and spinal cord. The SP concentrations were also significantly higher in the thalamus, pons, thoracic and lumbar spinal cord. The findings suggest that changes in TRH and SP concentration in the brain might be relevant to the motor dysfunction of shambling mouse.

Effects of histamine and related compounds on the release of immunoreactive thyrotropin-releasing hormone from the rat stomach in vitro.

Effects of histamine and related compounds on the release of immunoreactive thyrotropin-releasing hormone (ir-TRH) from the rat stomach in vitro were studied. The rat stomach was incubated in medium 199 with 1.0 mg/ml of bacitracin and 100 micrograms/ml of ascorbic acid (pH 7.4) for 20 min. The amount of TRH release into the medium was measured by radioimmunoassay. The ir-TRH release from the rat stomach was enhanced significantly in a dose-related manner with the addition of histamine and inhibited with the addition of famotidine, but not with mepyramine. The stimulatory effect of histamine on ir-TRH release from the stomach was partially blocked with the addition of famotidine, but not with mepyramine. The elution profile of acid-methanol-extracted rat stomach on Sephadex G-10 was identical to that of synthetic TRH. These findings suggest that histamine stimulated ir-TRH release from the rat stomach in vitro, and that histamine's effects may be mediated via a H2-receptor.

Gangliosides modulate Schwann cell proliferation and morphology.

We examined the effect of gangliosides on Schwann cell cultures isolated from neonatal rat sciatic nerves. Addition of gangliosides (GM1, GM3, and ganglioside mixture) at concentrations between 0.25 and 2 mg/ml significantly diminished both the baseline rate of proliferation of the Schwann cells and their response to two types of mitogens, the axolemmal fragments and derivatives of adenosine 3'-5'-monophosphate (cAMP). Gangliosides, the sialic acid residue of which had been removed, were highly toxic to the Schwann cells, which went to indicate that sialic acid is necessary to produce the inhibitory effects. Gangliosides also produced prominent changes in the morphological appearance of the Schwann cells. Most of the Schwann cells treated with gangliosides had an elongated shape with long processes and an alignment of end-to-end or side-by-side cell adhesion. These effects of gangliosides apparently were not mediated by cAMP, since intracellular cyclic adenosine monophosphate (cAMP) of Schwann cells at a basal- and forskolin-stimulated level was not altered by the exogenous gangliosides. These findings indicate that the direct effect of gangliosides on Schwann cells should also be considered as a background mechanism of ganglioside-induced facilitation of neuronal regeneration.

Differential signaling cascade of MAP kinase and S6 kinase depends on 3',5'-monophosphate concentration in schwann cells: correlation to cellular differentiation and proliferation.

Schwann cells produce myelin in the peripheral nervous system (PNS) and play an important role in the maintenance of the normal function of PNS. Our previous studies have shown that derivatives of adenosine 3',5'-monophosphate (cAMP) can regulate the cell-fate (i.e., proliferation and differentiation into cell surface galactocerebroside-positive cells) depending on its concentration in vitro. Higher concentration of cAMP can induce the expression of cell surface galactocerebroside, while proliferation can be induced by lower concentration of cAMP. However, the detailed molecular mechanism of how the same second messenger yields different phenotypes of Schwann cells depending on its concentration remains to be elucidated. Here we show that low concentration of 8-bromo cAMP, a cell-permeable derivative of cAMP, activates S6 kinase activity with a short-lived activation of mitogen-activated protein kinase (MAPK), whereas high dose of the reagent activates S6 kinase much less than that of low dose with a small and prolonged activation of MAPK in Schwann cells. These data clearly demonstrated that a rise in the intracellular cAMP uses the MAPK-S6 kinase pathway as an intracellular sinaling cascade and different magnitude and duration of the activation of this pathway might underlie the different cellular fate depending on the intensity of the stimulation.