Bioactivity of thyrotropin (TSH) in patients with central hypothyroidism: comparison between in vivo 3,5,3'-triiodothyronine response to TSH and in vitro bioactivity of TSH

To investigate the cause(s) of central hypothyroidism with normal or elevated TSH concentrations, we evaluated the bioactivity of serum TSH as well as pituitary and thyroid function. Seven hypothyroid patients had documented deficiencies of anterior pituitary hormones other than TSH. Basal TSH concentrations ranged from 2.2-14.8 microU/mL. Six patients had low T4 and free T4 concentrations; the remaining patient had a low free T4 and a low normal T4 level with an elevated TSH concentration of 14.4 microU/mL. The mean increment in TSH 30, 60, and 90 min after TRH administration (mean delta TSH) in these patients was 13.5 +/- 9.1 microU/mL (mean +/- SD), which was not significantly different from the value in controls (9.2 +/- 3.5 microU/mL). However, the ratio of the T3 increment at 120 min (delta T3) to mean delta TSH (delta T3/mean delta TSH) in patients was 53.9 +/- 29.3 ng/microU, significantly lower than the control value of 239.5 +/- 97.5 ng/microU (P < 0.01), suggesting that the thyroid response to endogenous TSH was blunted. The serum T4 concentration correlated with the mean delta TSH in these patients (r = 0.78; P < 0.05), suggesting that hypothyroidism is dependent on conserved pituitary function. The mean bioactivity to immunoreactivity ratio of basal TSH in patients was 0.97 +/- 0.27 and was not significantly different from the normal value of 1.05 +/- 0.22. One of the two patients with high basal TSH (> 10 microU/mL) had a ratio of 0.59, which is just below the mean +/- SD of normal subjects (0.61), suggesting that most patients had normal TSH bioactivity in vitro. Our findings suggest that in vivo bioactivity of TSH is decreased because of a pituitary disorder, but in vitro bioactivity of TSH is variable in patients with central hypothyroidism.

Monoclonal thyroglobulin autoantibodies: variable region analysis and epitope recognition

A panel of human monoclonal thyroglobulin (Tg) autoantibodies (TgAAb) has been used to analyze autoantigenic determinants on human Tg and to investigate the relationship between variable (V) region gene sequences and epitope specificity. Two monoclonal TgAAb bound to the same (or closely related) epitope on Tg, and these were defined as type I TgAAb. Three other monoclonals bound to a different site and were defined as type II TgAAb. Inhibition studies with mixtures of type I and type II monoclonal TgAAb (Fab)2 preparations indicated that a mixture of the (Fab)2s almost completely inhibited (> 75%) labeled Tg binding to intact TgAAb in the sera of apparently healthy blood donors and patients with autoimmune thyroid disease (AITD). Type I TgAAb predominated in apparently healthy blood donors' sera, whereas type II TgAAb predominated in AITD sera. Analysis of V region gene sequences of the TgAAb indicated that a range of light chain and heavy chain genes from different gene families was used. Furthermore, the same germline genes that are used by TgAAb are also well represented in the genes coding for other self- and nonself-reactive antibodies. No homology in terms of light chain and heavy chain gene families, germline gene usage, or complementarity determining region sequences was observed in TgAAb directed to the same or closely related epitopes. Our studies show that TgAAb are directed to two major conformational epitopes on the Tg molecule and that the proportion of TgAAb directed to these epitopes in apparently healthy blood donors and that in patients with AITD appear to be different. TgAAb derived from different germline genes and with different complementarity determining region sequences can display similar epitope specificity, and this indicates that AAb directed to the same or a closely related epitope show considerable heterogeneity at the molecular level.

Characterization of signaling pathways to Na+/H+ exchanger activation with epidermal growth factor in hepatocytes

To investigate the signaling pathways to Na+/H+ exchanger activation with epidermal growth factor in hepatocytes, we measured changes in cytosolic free calcium and intracellular pH levels at the single-cell level using digital imaging fluorescence microscopy of fura-2- or BCECF-loaded hepatocytes in primary culture. Epidermal growth factor induced cytosolic free calcium oscillations consisting of periodic trains of spikes with a latency period of up to several minutes. These calcium responses were inhibited by tyrosine kinase inhibitor genistein (100 mumol/L) and abolished by emptying of intracellular Ca2+ pools with 3 mumol/L thapsigargin, an inhibitor of Ca(2+)-ATPase on the endoplasmic reticulum. Epidermal growth factor (1 nmol/L) induced an intracellular pH increase of 0.12 +/- 0.07 units from the basal level of 7.25 +/- 0.09 units after several minutes of latency. This effect was completely abolished by 1 mmol/L amiloride, an inhibitor of the Na+/H+ exchanger. The epidermal growth factor-induced intracellular pH increase was inhibited by pretreatment of hepatocytes with genistein (100 mumol/L), thapsigargin (3 mumol/L) or calmodulin inhibitor W-7 (25 mumol/L), but not with protein kinase C inhibitor H-7 (50 mumol/L) or with cyclic AMP-dependent kinase inhibitor H-8 (60 mumol/L). Phorbol ester PMA (phorbol 12-myristate 13-acetate), a potent activator of protein kinase C, induced a slight intracellular pH increase significantly smaller than that with epidermal growth factor, whereas this effect was completely blocked by pretreatment with H-7, indicating that PMA-induced intracellular pH increase is mediated by protein kinase C pathways, unlike epidermal growth factor.(ABSTRACT TRUNCATED AT 250 WORDS)

Close correlation between the dephosphorylation of p53 and growth suppression by transforming growth factor-beta 1 in nasopharyngeal carcinoma cells transduced with adenovirus early region genes

The mechanism of growth inhibition by transforming growth factor (TGF)-beta 1 was investigated. We examined the growth inhibitory effects of TGF-beta 1 on human nasopharyngeal carcinoma (KB) cells which constitutively expressed p53. TGF-beta 1 suppressed the DNA synthesis of KB cells in a dose-dependent manner. It had minimal effect on adenovirus-2-transduced KB cells expressing either adenovirus early region 1B (E1B) or 1A (E1A) product, which respectively binds to p53 or Rb product and inhibits its function, and no growth inhibition at all was observed with KB cells expressing both E1B and E1A products. Dephosphorylation of the p53 was promoted by TGF-beta 1 stimulation in KB cells, but not in E1B-producing KB cells, which sequestrate the function of p53. The growth inhibition of KB cells by TGF-beta 1 was significantly reduced by treatment with okadaic acid. These results suggest that p53 transduces the antiproliferative signal of TGF-beta 1 possibly through its dephosphorylation.

Increased expression of c-met messenger RNA following acute gastric injury in rats

The aim of the present study was to evaluate messenger RNA expression of c-met, a hepatocyte growth factor receptor gene, after gastric mucosal injury in rats. Male Sprague-Dawley rats were fasted for 24 hours, received 0.6 N hydrochloric acid (HCl), and served for polyadenylated RNA extraction from the oxyntic gastric mucosa. The transcripts of rat c-met gene were analyzed by reverse-transcript polymerase chain reaction and Northern blotting. Although it was detected even before the HCl administration, the c-met expression increased 6, 24 and 48 hours after the HCl administration. Thereafter, gastric mucosal injury diminished and the c-met expression declined. Hepatocyte growth factor reportedly plays an important role in gastric cell proliferation. The increased c-met expression indicates that this gene may participate in the healing process of gastric mucosa after injury.

Transforming growth factor beta 1 secreted from scirrhous gastric cancer cells is associated with excess collagen deposition in the tissue

To explore the mechanism of increased collagen deposition in scirrhous carcinoma of the stomach, an attempt was made to define the role of transforming growth factor beta 1 (TGF-beta 1), secreted from tumour cells, as a possible humoral factor which functions in a paracrine manner to stimulate the production of collagen in regional fibroblasts. Immunohistochemical staining revealed that tumour cells in scirrhous carcinomas were generally stained more intensively than those in other types of carcinomas. On Northern blot analysis the tumour cells established from scirrhous carcinoma (KATO-III, OCUM-1 and HSC-39) exhibited relatively strong signals compared with those from non-scirrhous carcinoma (MKN-28 and MKN-45). In the culture media of scirrhous carcinoma cells, the active form of TGF-beta 1 was detected, while in those of the non-scirrhous carcinoma cells the latent form was demonstrated by both colony and radioreceptor assays. The culture medium from KATO-III showed strong stimulating activity of collagen synthesis in fibroblasts, and this activity was partially neutralised by an anti-TGF-beta 1 antibody. These results suggest that tumour cells in scirrhous carcinoma produce more active-form TGF-beta 1 than does non-scirrhous carcinoma and thus is partially responsible for the observed enhanced collagen deposition in the region.

Origin of the right pulmonary artery from the ascending aorta. Longest survivor without receiving surgical repair

We report a case of origin of the right pulmonary artery from the ascending aorta. Pulmonary arteriography showed an opacification of the enlarged left pulmonary artery without filling of the right pulmonary artery. Pressure study showed that the pulmonary systolic pressure was almost equal to the systemic pressure. The present case is characterized as the longest-term survivor in the literature with aortic origin of right pulmonary artery without receiving surgical repair.

Familial unresponsiveness to thyrotropin by autosomal recessive inheritance

Unresponsiveness to TSH has been identified and sufficiently studied in only three patients. We report siblings with this defect as the first documentation of familial occurrence. A 26-yr-old woman was diagnosed with congenital hypothyroidism during infancy. The thyroid was atrophic, and thyroid function tests without T4 replacement showed serum free T4 levels below 3 pmol/L, serum TSH of 125 mU/L, and serum thyroglobulin below 5 mg/L. 123I scintigram showed decreased uptake (5% at 24 h), but normal shape at the correct position in the neck. Autoantibodies against thyroglobulin, thyroid peroxidase, and TSH receptor in serum were not detected. The amount of cAMP released into FRTL-5 cell culture in the presence of TSH from the patient was not different from that released by the same amount of TSH from normal subjects, suggesting that TSH bioactivity in our patient was normal. The brother of the patient also had congenital hypothyroidism, and the data on his thyroid function was similar to that for his sister. There was a consanguineous marriage in the parents of the siblings, and the mother of the patients had a normal serum free T4 level, but slightly increased serum TSH and thyroglobulin levels, indicating subclinical hypothyroidism. The possible pathogenesis of TSH unresponsiveness in our patients includes a mutation in the TSH receptor gene, abnormality in transcription-regulating factor, abnormality in GTP-binding protein, and/or inhibition of the action of cAMP. The family history of the patients suggests that the mode of inheritance in TSH unresponsiveness is autosomal recessive.

Coronary spasm as a cause of coronary thrombosis and myocardial infarction

A 63-year-old man with an acute anterior myocardial infarction demonstrated an intracoronary nonocclusive thrombus distal to the organic stenosis of the left anterior descending coronary artery. One month after the infarction the thrombus was completely dissolved, and spontaneous and provoked spasm occurred overlying the organic stenosis of the coronary artery. Thus coronary spasm superimposed on the atherosclerotic stenosis was suggested as a cause of the thrombus formation that led to myocardial infarction.

[Vitreous surgery for mycotic endophthalmitis]

We treated eight eyes of five patients with mycotic endophthalmitis. Intraocular inflammatory changes in one of these eyes improved only by antifungal therapy with 21-day administration of miconazole and fluconazole. The other seven eyes underwent vitrectomy, and the preoperative periods between the onset of ocular complications and the operation ranged from one and a half months to three months, during which time fungi were isolated only in one case. Dense vitreous opacities caused by the colonies of the fungi were found in the all vitrectomized eyes. Vitrectomy in the three cases showing no retinal detachment was effective for the improvement of either visual acuity or ophthalmoscopic findings, whereas vitrectomy was not effective in the other two cases with the occurrence of the pre-retinal membrane causing traction retinal detachment. The present investigations suggest that persistent endophthalmitis and the appearance of total retinal detachment made the improvement of retinal changes difficult because of the inflammatory and fibrotic processes between the retina and the vitreous body. It, therefore, is shown that anti-fungal therapy should be initiated when mycotic endophthalmitis is suspected, but in cases without response to the drug, vitrectomy should be performed before retinal detachment occurs.

Expression of the c-met/hepatocyte growth factor receptor gene during rat liver regeneration induced by carbon tetrachloride

The hepatocyte growth factor is closely related to liver regeneration. And the c-met protooncogene is reported to encode a hepatocyte growth factor receptor. Little is known, however, about how the c-met gene is activated during liver regeneration. In this study, we demonstrated that expression of the c-met gene/hepatocyte growth factor gene was enhanced, with a distinct peak, following carbon tetrachloride administration, i.e., the gene expression was activated at 6 hours after the treatment, then decreased, and again increased. The present study suggested that this gene could be responding to liver regeneration and that the hepatocyte growth factor receptor plays an important role in regulating cell cycle progression prior to elevation of deoxynucleic acid synthesis during liver regeneration.

[Expression of the protein kinase C genes during liver regeneration]

Protein kinase C (PKC) plays an important role in intracellular signaling. PKC consists of a family of at least eight distinct enzymes. How PKC can be responded to liver regeneration and growth is largely unknown. In an in vivo experiment, regenerating liver after partial hepatectomy (Hx) and carbon tetrachloride (CCl4) administration, expression of the PKC alpha-type was increased, with a single peak, after Hx and CCl4 administration. On the other hand, the PKC epsilon-type gene was activated with biphasic peaks following Hx but was elevated with a single peak after the CCl4 administration. In an in vitro experiment using primary cultured hepatocytes, both of the PKC alpha-type and epsilon-type genes could be induced only by combination of insulin and serum. These results demonstrate that both isoforms of PKC are identically regulated by extra- and intracellular stimuli, thereby influencing growth control of hepatocytes.

Measurement of erythrocyte Na,K-ATPase activity in normal pregnant women

To investigate the peripheral metabolic status during normal pregnancy, we measured the number of erythrocyte Na,K-ATPase units as well as the cation transport activity of the pump from 32 normal pregnant women and 12 normal controls. The number of pump units determined by maximal ouabain binding to erythrocyte in normal pregnancy was significantly higher than that in normal controls (mean +/- SEM: 0.52 +/- 0.03 vs. 0.39 +/- 0.04 pmol/10(9)RBC, P < 0.05). The total cation transport activity of the pump measured by 86Rb uptake also significantly increased during pregnancy (98.9 +/- 6.4 vs. 73.1 +/- 5.4 nmol/10(9) RBC, P < 0.01). However, the mean cation transport activity per pump unit, which was presumed to be an indicator of the peripheral metabolic status, was unchanged in any of three trimesters when compared with that in normal controls. Serum FT4 levels measured by two different methods were significantly lower in the third trimester than in the first trimester (P < 0.01). In conclusion, erythrocyte Na, K-ATPase activity per pump unit is normal in pregnant women, suggesting that the peripheral metabolic status in pregnancy seems to be normal. Increases in both the number and function of the pump may be influenced by factors other than thyroid function.

Anomalous origin of the left anterior descending coronary artery from the right sinus of Valsalva associated with effort angina pectoris

A 54-year-old man suffering from effort angina pectoris had an anomalous origin of the left anterior descending coronary artery (LAD) from the right sinus of Valsalva (RSV). The anomalous LAD with a small ostium and without other significant narrowing initially ran into the interventricular septum and subsequently the anterior interventricular groove. Coronary angiography during the anginal attack induced by ergometer exercise testing revealed neither an enhanced narrowing of the LAD ostium, nor myocardial squeezing of the LAD at the interventricular septum level, nor coronary vasospasm. Myocardial ischaemia associated with an anomalous aortic origin of the LAD from the RSV is extremely rare, especially when the vessel runs a septal course. In the present case, the ostial stenosis of the anomalous LAD, probably due to developed atherosclerosis, seemed to be the most likely cause of the exertional angina.

Production and characterisation of a human monoclonal thyroid peroxidase autoantibody

A human-mouse hybridoma has been produced by fusion of Hashimoto thyroid lymphocytes with the mouse myeloma line X63-Ag8.653. The cloned hybridoma secreted 2.5 micrograms per 10(6) cells per day of an IgG kappa thyroid peroxidase (TPO) autoantibody (2G4) with high affinity (2.5 x 10(9) molar-1) and specificity for human TPO. 2G4 did not react with lactoperoxidase, horseradish peroxidase or human myeloperoxidase or with porcine TPO or with human thyroglobulin. Plastic tubes coated with 2G4 bound about 50% of 125I-labelled human TPO added and the binding was inhibited by IgGs prepared from 18/18 TPO autoantibody-positive sera. This indicated that all 18 sera contained autoantibodies which recognised the same (or closely related) epitope as 2G4. Plastic tubes coated with IgGs from different TPO autoantibody-positive patient sera also bound 125I-labelled TPO but inhibition by 2G4 in this system was not complete. This suggested that the sera contained at least 2 types of TPO autoantibodies, with only one type of autoantibody reactive with the same epitope as 2G4.

[A case of hypereosinophilic syndrome exhibiting left ventricular systolic dysfunction]

A 16-year-old woman suffering from bronchial asthma since 2 years previously was admitted to the hospital because of high grade fever, dyspnea, skin eruption and arthralgia. Laboratory data revealed pronounced eosinophilia with elevated immunoglobulin E value. A chest X-ray film showed cardiomegaly with pulmonary congestion. Left ventriculograms showed diffusely reduced motion of the left ventricle (LV). Various clinical symptoms and laboratory data were resolved shortly after the administration of corticosteroids, but the LV dysfunction persisted for at least three months. Left ventriculograms 2 years later disclosed a marked improvement of the LV wall motion. In both the acute and the chronic phase, endomyocardial biopsy of both ventricles revealed non-specific histological findings comprising disarrangement of myocytes and interstitial fibrosis, suggesting post-myocarditis. This case was characterized by LV dysfunction possibly due to eosinophilic myocarditis associated with hypereosinophilic syndrome, and by its functional improvement with long-term corticosteroid therapy.

Microvascular geometry of the rat heart. Arteriolar and venular capillary regions

The importance of realistic data regarding microvascular geometry for the understanding of oxygen transport to tissue cannot be underestimated. The purpose of the present investigation was therefore to determine the pattern of capillarization in rat myocardium. The histochemical method used in this study was novel in that it allowed for the discrimination of arteriolar capillary (AC) and venular capillary (VC) regions on the basis of color. Our preeminent finding was that systematic differences exist in microvascular geometry from arteriolar to venular capillary regions in normal rat myocardium. Specifically, VC regions are characterized by greater capillary density; more uniform capillary spacing; shorter segment lengths; and increased capillary diameter. These differences translate to significantly greater capillary length, surface and volume densities on the venular side of the capillary bed. In the face of lower PO2 values towards venules, this distinctive geometry would serve to provide advantageous geometric conditions for oxygen diffusion.

[A case of painless myocardial injury probably caused by coronary artery spasm]

A 53-year-old male was admitted to the hospital due to electrocardiographic ST-segment elevation in V1-4 with ST-segment depression in the inferior leads, which suggested acute myocardial infarction. He had a cough and a slight fever without chest pain. Serum creatine kinase and its myocardial band were slightly elevated but creatine kinase value did not exceed twice the normal upper limit. Emergent coronary arteriography (CAG) revealed intact coronary arteries. The CAG in a chronic stage again revealed intact coronary arteries. Intracoronary administration of acetylcholine of 100 micrograms to the left coronary artery and 50 micrograms to the right coronary artery provoked diffuse spasm in the right and left coronary arteries. The electrocardiogram (ECG) during the right coronary artery spasm revealed ST-segment depression in the inferior leads with ST-segment elevation in V2 and V3, which resembled the ECG finding at the time of the patient's admission. With intracoronary isosorbide dinitrate, the spasm and ST-segment elevation were resolved. These findings strongly suggest that coronary spasm can cause myocardial injury indicated by a slight elevation of serum creatine kinase value.

[Coronary spasm-induced acute myocardial infarction associated with intracoronary thrombosis]

A 63-year-old man was admitted with an acute anteroseptal myocardial infarction. Coronary angiography performed 3 hours after the onset of chest pain revealed 99% stenosis of the proximal left anterior descending coronary artery (LAD) with delayed filling and intraluminal thrombus distal to the stenosis. After the intracoronary injection of isosorbide dinitrate, the delayed filling disappeared and a subsequent intracoronary urokinase partially dissolved the thrombus. Repeat coronary angiography in the chronic phase disclosed 75% stenosis of the LAD and disappearance of the thrombus. Intracoronary acetylcholine provoked a coronary spasm at the stenotic site of the LAD, concomitantly with chest pain and ST-segment elevation in the anterior leads. The present case demonstrated that coronary spasm plays an important role in thrombus formation and acute myocardial infarction. To date, the concept has been postulated that a dynamic interaction between atherosclerosis, platelet aggregation and spasm may work to cause coronary thrombosis and subsequently lead to acute myocardial infarction. Our report shed light on the importance of coronary spasm in the pathogenesis of myocardial infarction.