Thyrotropin binding specificity for the thyrotropin receptor

Recently, highly purified bovine thyrotropin (bTSH) of pituitary origin, as well as recombinant human (h) TSH free of lutropin (LH) contamination, has been reported to activate the LH/choriogonadotropin receptor (LH/CGR). These data challenge the concept of TSH specificity for its own receptor. We, therefore, re-evaluated these data using, as targets, the recombinant hTSH and rat LH/CGRs stably expressed in Chinese hamster ovary (CHO) cells. Partially purified bTSH (2 IU/mg protein) and, to a lesser degree, highly purified bTSH (30 IU/mg protein) increased intracellular cAMP levels in CHO-LH/CGR cells (an EC50 of 0.2 and > 20 mIU/ml, respectively). In contrast, recombinant hTSH (up to 1 IU/ml) did not. All three TSH preparations increased cAMP levels to the same extent in CHO-TSHR cells (an EC50 of 0.3 mIU/ml). Furthermore, we observed only nonspecific, low affinity TSH binding for CHO-LH/CGR cells and also for CHO cells transfected with the expression vector alone (a Kd of 100 nM), although both high and low affinity TSH binding was demonstrated in CHOT-SHR cells (a Kd of 0.3 and 100 nM, respectively). These data indicate that even highly purified bTSH of pituitary origin contains significant amounts of LH, and that TSH itself does not appear to activate the LH/CGR.

Pick's disease immunohistochemistry: new alterations and Alzheimer's disease comparisons

Pick's disease (PD) brains were examined immunohistochemically for the expression of antigens known to be associated with Alzheimer's disease (AD) lesions. Most antibodies which label intracellular neurofibrillary tangles (NFTs) in AD were found to stain Pick bodies (PBs). Among them was the monoclonal antibody A2B5, which is known to recognize neuronal surface gangliosides. This result indicates that membrane proteins are probably incorporated into PBs as into NFTs. However, PBs, in contrast to NFTs, showed a paucity of staining for heparan sulfate glycosaminoglycan and basic fibroblast growth factor (bFGF). Staining for midkine, seen in senile plaques in AD, was not seen in PD. The relative lack of staining for these two neurotrophic factors in PD brain may reflect underlying mechanisms which are distinct from those in AD. We also describe two glial abnormalities in PD: glial fibrillary tangles and clusters of granules positive for the complement protein C4d in the hippocampal dentate fascia. These are presumably related to complement-activated oligodendroglia, and both pathological structures are more abundant in advanced cases, suggesting that they may be hallmarks of the disease progression.

Amyloid peptides are toxic via a common oxidative mechanism

beta-Amyloid protein (A beta) is a member of a small group of proteins that accumulate as amyloid deposits in various tissues. It has recently been demonstrated that the toxicity of A beta toward some neural cells is caused by oxidative damage. Since all of the amyloid diseases are characterized by protein deposited in the antiparallel beta-sheet conformation, it was asked whether there is a common toxic mechanism. It is shown here that the protein components of other human amyloidoses, including amylin, calcitonin, and atrial natriuretic peptide, are all toxic to clonal and primary cells. The toxicity is mediated via a free radical pathway indistinguishable from that of A beta. Experiments with synthetic peptides suggest that it is the amphiphilic nature of the peptides generated by their beta structure rather than their beta structure per se that causes toxicity. These results tend to rule out the alternative that amyloid toxicity is exclusively mediated via specific cell surface receptors.

A new fluorescent imaging procedure in vivo for evaluation of the retinal microcirculation in rats

We investigated a new method for in vivo evaluation of the retinal microcirculation in rats using a cell-permeant fluorescent dye, acridine orange (AO), which stains cell nuclei and cytoplasm, and a scanning laser ophthalmoscope (SLO). AO, which binds and interacts with DNA and RNA, and thus stains cell nuclei and cytoplasm, was administered intravenously to rats. Fluorescein angiography was performed after administration of the AO, and fundus images were recorded on S-VHS videotape by means of an SLO. Argon laser was used as an exciter of the dye. The retinal vessels were stained with the dye, rendering the retinal microvasculature clearly visible. Cell nuclei and vessel walls were observed as greater fluorescence and lesser fluorescence, respectively. Leukocytes were also observed as highly fluorescent dots moving through the vessels. The results suggest that SLO visualization of AO uptake by cells may be a useful procedure for the evaluation of retinal microcirculation in vivo in rats.

Regional myocardial sympathetic dysinnervation in patients with coronary vasospasm

The purpose of this study was to assess the presence and location of impaired myocardial sympathetic innervation by using 123I metaiodobenzylguanidine (123I MIBG) in 15 patients with coronary vasospasm induced by intracoronary acetylcholine. The results were compared with those using thallium-201 (Tl-201). We also examined 14 patients with severe coronary stenosis (> 90%) and 8 control subjects without significant coronary stenosis (< 50%) and provokable coronary vasospasm. Regional myocardial sympathetic dysinnervation was detected by 123I MIBG single-photon emission computed tomography (SPECT) in all patients with coronary vasospasm, despite normal uptake during Tl-201 SPECT. This regional uptake-mismatch between 123I MIBG and Tl-201 Spect occurred specifically in the vasospasm group (p < 0.001 vs stenosis and control groups). Moreover, regional myocardial sympathetic dysinnervation was located in the distribution of perfusion in 25 of the 27 vasospasm-induced vessels. Normal uptake of 123I MIBG was observed in the perfused areas in 16 of the 18 non-vasospasm-induced vessels. The sensitivity ans specificity of 123I MIBG for detection of coronary vasospasm were 92% and 88% respectively. In patients with coronary vasospasm, we found regional myocardial sympathetic dysinnervation to be present. Furthermore, we were able to distinguish these patients from patients with critical coronary stenosis by 123I MIBG and Tl-201 SPECT.

Three cases of chemotherapy-induced acral erythema

Three cases of chemotherapy-induced acral erythema are reported. All the patients had received cyclophosphamide, vincristine, adriamycin, prednisolone, and granulocyte-colony stimulating factor (G-CSF) for the treatment of leukemia or malignant lymphoma. From 35 to 45 days after the start of chemotherapy, painful erythematous lesions developed on their palms, soles, fingers, and toes, resulting in blister formation and desquamation. The recent higher incidence of chemotherapy-induced acral erythema may be correlated with the popularity of G-CSF, which allows the use of higher doses of chemotherapeutic drugs.

Evolution of Mirizzi syndrome with biliobiliary fistula

The mechanisms of fistula formation were analyzed in eight patients with Mirizzi syndrome with biliobiliary fistula. The fistula was type 1 in three patients and type 2 in five, according to the Corlette-Bismuth classification. The apparent mechanisms of fistula formation include inflammation of the gallbladder, its subsequent fusion to the bile duct, and increase in the internal pressure due to either contraction of the gallbladder or multiple stones. However, no predisposing conditions other than a longstanding history of cholelithiasis have been suggested. Differences in the type of fistula are considered to be due to the mode of fusion of the gallbladder to the bile duct, and the size of the perforation, which is apparently determined by the area in contact with the stone.

Suppressive doses of thyroxine do not accelerate age-related bone loss in late postmenopausal women

To examine whether suppressive doses of thyroxine have any adverse effects on bone, we evaluated various bone metabolic markers (lectin-precipitated alkaline phosphatase, osteocalcin, carboxyl-terminal region of type I collagen propeptide, tartrate-resistant alkaline phosphatase, and urinary excretion of hydroxyproline and pyridinium crosslinks), incidence of vertebral deformity, total body and regional (lumbar spine and radius) bone mineral densities (BMDs), and rates of bone loss in 24 late postmenopausal (more than 5 years after menopause) women who were treated with levothyroxine (L-T4) after total thyroidectomy for differentiated carcinoma. Depending on the clinical records, including serum TSH levels measured by immunoradiometric assay, these patients were divided into two groups. One group of patients was given suppressive doses of L-T4 (TSH < 0.1 mU/L, n = 12) and the other group was given nonsuppressive doses of L-T4 (TSH > 0.1 mU/L, n = 12). There was no difference in bone metabolic markers and incidence of vertebral deformity between the groups. In patients with TSH suppression, Z-scores of BMDs calculated from age-matched healthy women (n = 179, aged 55 to 80) were nearly in the zero range of values (0.077 at total body, 0.228 at lumbar spine, and -0.117 at trabecular region of lumbar spine). The rate of bone loss in TSH-suppressed patients (-0.849 +/- 0.605%/year) was not significantly different from that of nonsuppressed patients (-0.669 +/- 0.659). These prospective and cross-sectional data suggest that long-term levothyroxine therapy using suppressive doses has no significant adverse effects on bone.

Metabolic alterations in the neonate and infant brain during development: evaluation with proton MR spectroscopy

PURPOSE

To evaluate the usefulness of hydrogen-1 magnetic resonance (MR) spectroscopy in the evaluation of the developing brain.

MATERIALS AND METHODS

Localized MR spectra were obtained with an echo time of 272 msec from the brain of 78 neonates and infants aged 1 week to 100 months. All patients were retrospectively classified into three groups on the basis of neurologic development: abnormal (group 2, n = 21), normal despite minor neurologic signs (group 1, n = 23), and normal (group 0, n = 34).

RESULTS

Seventeen patients in group 2 and eight patients in group 1 revealed abnormally low N-acetylaspartate (NAA)/choline or NAA/creatine ratios compared with those obtained in group 0. MR spectroscopy was slightly more useful in the differentiation of patients in groups 2 and 1 (chi 2 test, P < .005) than MR imaging (P < .01).

CONCLUSION

H-1 MR spectroscopy provides prognostic information about the brain in healthy and neurologically damaged infants and augments the value of MR imaging.

Case report of a patient with multiple lesions of the stomach, including multiple cancers and an adenomatous polyp

This paper describes an unusual case of an 80-year-old man followed up for multifocal gastric cancers. There were three separate polypoid carcinomas and one adenomatous polyp with no sign of malignancy. We measured the DNA content of the gastric cancer and adenomatous cells obtained from endoscopically biopsied specimens. The adenomatous polyp and one of the cancerous lesions showed DNA diploidy. The other two cancerous lesions showed DNA aneuploidy, with different DNA index (DI) values (1.12 and 1.64, respectively). It is considered that the three cancers arose from different stem lines. However, an operation was not performed because the patient refused gastrectomy, and therefore only conservative follow up has been continued. Presentation of this case is followed by a detailed discussion focusing on the possible development of carcinoma in gastric adenomatous polyps in view of the data from the literature.

Intussusception of the cecum with calcified fecaliths

We treated a patient with a complete invagination of the cecum that contained two large laminated calcified fecaliths. Colonofiberscopy showed a dimpling submucosal tumor that was palpated as a bony hard tumor at laparotomy. This finding suggested that the fecaliths caused intussusception of the cecum and that such an intussusception should be suspected when a bony hard, dimpling submucosal tumor is found in the cecum. To our knowledge, this is the first reported case of a cecal invagination accompanied by calcified fecaliths without an appendical intussusception.

Structural and functional significance of cysteine residues of glutathione-independent prostaglandin D synthase. Identification of Cys65 as an essential thiol

Glutathione-independent prostaglandin D synthase in rat brain is composed of 189 amino acid residues and catalyzes the isomerization of prostaglandin H2 to prostaglandin D2, an endogenous sleep-promoting substance. This enzyme is the only enzyme among members of the lipocalin superfamily composed of various secretory lipophilic ligand-carrier proteins and is recently identified to be a beta-trace protein, a major constituent of human cerebrospinal fluid. We expressed the active enzyme in Escherichia coli and then systematically substituted all cysteine residues of the delta 1-29 enzyme at positions of 65, 89, and 186 with alanine or serine. The parent and mutant enzymes were purified to apparent homogeneity with a recovery of approximately 30% by chromatography with Sephadex G-50 and S-Sepharose, by which all the enzymes showed identical elution profiles. The purified enzymes, irrespective of the mutation, showed almost the same circular dichroism spectral characteristics as displayed by a highly ordered beta-structure. The recombinant enzymes containing Cys65 showed the activity comparable with that of the enzyme purified from rat brain (approximately 3 mumol/min/mg of protein) in the presence, but not in the absence, of sulfhydryl compounds. However, all of the single, double, and triple mutants without Cys65 lost the enzyme activity. The purified delta 1-29 Ala89,186 enzyme was inactivated reversibly by conjugation with glutathione at Cys65 and irreversibly by the stoichiometric chemical modification with N-ethylmaleimide. These results indicate that Cys65 is an essential thiol of the enzyme and that both the intrinsic and extrinsic sulfhydryl groups are necessary for nonoxidative rearrangement of 9,11-endoperoxide of prostaglandin H2 to produce prostaglandin D2 catalyzed by the enzyme.

Anterior ischemic optic neuropathy associated with pulseless disease

A 41-year-old man with pulseless disease presented with a sudden onset of visual loss in the right eye. The right fundus showed moderate optic disk swelling with mild pallor. Aortography demonstrated bilateral obstruction of the common carotid arteries and left subclavian artery, and only collateral vessels supplied the upper portion. Temporal artery biopsy revealed no inflammation. In addition, the patient originally had relatively small disks. This anatomical factor and marked hypoperfusion of the posterior ciliary artery presumably caused nonarteritic anterior ischemic neuropathy in this patient.

Quantitative evaluation of leukocyte dynamics in retinal microcirculation

PURPOSE

Leukocyte rheology may play a key role in microcirculation because leukocytes have unique properties, such as large cell volume, high cytoplasmic rigidity, and low deformability. However, only a few methods are available to study the dynamic behavior of leukocytes in retinal microcirculation. The authors developed a new method to analyze directly movements of leukocytes in the retinal vessels of primates.

METHODS

Acridine orange, which has been used as a nuclear stain in histochemistry and cytochemistry, was injected intravenously into cynomolgus monkeys for a vital staining of leukocytes. The fundus image was generated with the argon blue laser and a scanning laser ophthalmoscope. The images were recorded on a magnetic tape and evaluated with a personal computer-based image analysis system.

RESULTS

Each leukocyte was recognized as a single fluorescent dot moving in the retinal vessels. It was possible to analyze the spatial and temporal dynamics of individual leukocytes in the capillaries. Some leukocytes passed through the capillaries, plugging transiently under the physiological condition. Leukocytes that stayed in the same position for a few minutes may have stuck to the endothelium as a result of leukocyte-endothelial interactions. In the postcapillary vessels, leukocytes tended to be displaced from the center stream toward the vessel walls. The mean flow velocity of leukocytes in the perifoveal capillary was 0.92 +/- 0.32 mm/sec.

CONCLUSIONS

This study clearly demonstrated that rheologic behaviors of leukocytes in the retinal microcirculation can be studied through the vital staining with acridine orange in vivo. The authors' results suggest a potential role of leukocytes in retinal vascular flow disturbances. This study may open the door to the investigation of leukocyte hemodynamics in the retinal microcirculation in vivo.

Maternal plasma endothelin levels and fetal status in normal and preeclamptic pregnancies

Endothelin (ET) is a potent vasoconstrictor peptide. In this study, we investigated maternal venous plasma ET levels measured by Sandwich-enzyme immunoassay within a week before the onset of labor, and measured plasma renin activity and plasma aldosterone concentration by radioimmunoassay in normal and severely preeclamptic pregnancies. Also, we determined umbilical cord blood pH and gas concentrations after spontaneous vaginal deliveries and cesarean sections. There was a significant (p < 0.01) negative correlation between maternal ET levels within 1 week before the onset of labor and birth weights. There was no significant correlation between maternal ET levels and umbilical gas concentrations. These data suggest that the correlation is the result of decreasing uteroplacental blood flow. We speculate that increased maternal ET expresses not only maternal renal vascular endothelial injury but also other vascular endothelial injuries. These vascular injuries may occur at least 1 week before the clinical manifestation in the preeclamptic mothers and their fetuses.

[Does nocturnal hypoxia relate to acute exacerbation of chronic respiratory failure with right heart failure in late sequelae of pulmonary tuberculosis?]

Thirty-eight patients with late sequelae of pulmonary tuberculosis (TB seq.) were studied to clarify whether or not nocturnal oxyhemoglobin desaturation (NOD) could relate to acute exacerbation of chronic respiratory failure (AE). All patients had been untreated with home oxygen therapy, because they were not severely hypoxic. We performed sleep studies, pulmonary function tests and arterial blood gas analysis and investigated past history about AE in each patient. Twelve patients had experienced AE with right heart failure and they were classified as CHF (congestive heart failure) group. The rest was classified as Non-CHF group. These two groups were compared as for each variables examined. There was no difference between the two groups in age, body weight, %VC, FEV1.0%, and awake PaO2. Awake PaCO2 was significantly higher in CHF group. Although no difference was observed in baseline SaO2, the degree of NOD was significantly greater in CHF group when evaluated by lowest SaO2 during sleep and 85% desaturation time (total time spent with SaO2 less than 85%). Moreover, 21 of Non-CHF and 6 of CHF were studied for cardiac parameters using right side cardiac catherization. While the differences of mean pulmonary arterial pressure and cardiac output between the two groups were not significant, pulmonary arteriolar resistance was higher in CHF group. We concluded that NOD in TB seq. had a major role in AE with right heart failure. We speculated that AE might be caused, at least partly, by pulmonary vasopressor response to recurrent NOD.