Structure of a conformationally constrained Arg-Gly-Asp sequence inserted into human lysozyme

To examine the effect of a conformational constraint introduced into the Arg-Gly-Asp (RGD) sequence on cell adhesion activity, we constructed a mutant protein by inserting an RGD-containing sequence flanked by two Cys residues between Val74 and Asn75 of human lysozyme. The CRGDSC-inserted lysozyme was expressed in yeast, purified, and designated as Cys-RGD4. Using baby hamster kidney cells, Cys-RGD4 was shown to possess even higher cell adhesion activity than that of the RGDS-inserted lysozyme, RGD4. The Cys-RGD4 protein was co-crystallized with a lysozyme inhibitor, tri-N-acetylchitotriose, and the three-dimensional structure was determined at 1.6-A resolution by x-ray crystallography. In contrast to RGD4, the inserted RGD-containing region of Cys-RGD4 was well defined. The structural analysis revealed that the two inserted Cys residues form a new disulfide bond in Cys-RGD4, as expected, and that the RGD region assumes a type II' beta-turn conformation of Gly-Asp with a hydrogen bond between the C = O of Arg and the H-N of Ser. In addition, it was confirmed that two more hydrogen bonds are present in the RGD region of the Cys-RGD4 lysozyme. These results suggest that the conformation of the RGD-containing region is rigid and stable in the Cys-RGD4 molecule and that the type II' beta-turn structure of RGD is essential for binding to integrins with high affinity.

Localization of an isoform of carboxylesterase in rat brain differs from that in human brain

Liver carboxylesterase (CE) is an enzyme capable of metabolizing drugs, and may also function as a regulator of lipid metabolism. We examined two isoforms of CE (RH1 and RL1) by immunohistochemistry in rat brain. The anti-RL1 antibody did not stain any brain structures. The anti-RH1 antibody, however, stained oligodendrocytes in all brain tissues and tanycytes, as well as some neurons in the deep cingulate gyrus, various hypothalamic nuclei and the spinal trigeminal nucleus. In the central nervous system, rat CE may function as a protective factor against foreign chemicals in these glial and neuronal cells. The distribution differed from that of the homologous human isoform which has been previously found only in endothelial cells in human brain. A possible relation between RH1 positive neurons and the medial pain system is discussed.

Apolipoprotein E mRNA in the brains of patients with Alzheimer's disease

To clarify the role of apolipoprotein E (apoE) in the pathophysiology of Alzheimer's disease (AD), we used an RT-PCR method to investigate apoE and glial fibrillary acidic protein (GFAP) mRNA expression in the brain. ApoE mRNA was significantly more abundant in AD (0.379 +/- 0.191, mean +/- SD) than in control (0.125 +/- 0.073, p < 0.05) brain tissue, but in AD it was decreased in relation to the apoE-epsilon 4 gene dosage. The GFAP mRNA content also was greater in AD (5.96 +/- 2.94) than in control (3.80 +/- 2.78) tissue, and in AD showed an increase relative to the apoE-epsilon 4 gene dosage. AD patients who had long survival times showed high expression of apoE and low expression of GFAP. These results suggest that apoE suppresses the progression of AD, including gliosis, in the brain.

Determination and confirmation of methyl p-hydroxybenzoate in royal jelly and other foods produced by the honey bee

Methyl p-hydroxybenzoate (methyl paraben) in foods produced by the Honey Bee was determined by HPLC and confirmed by GC-MS. The compound was detected at a mean concentration of 22.3 +/- 6.8 mg/kg (between 14.2 and 31.9 mg/kg) in commercial royal jelly, but was not detected in honey, propolis or pollen lumps at the detection limit of 1 mg/kg. Fresh royal jelly collected from apiaries contained methyl p-hydroxybenzoate at a concentration of 20.3 +/- 4.7 mg/kg (between 12.5 and 31.7 mg/kg). These results indicate that the methyl p-hydroxybenzoate in royal jelly is not added but is a natural component.

Cloning and sequencing of a unique antigen MPT70 from Mycobacterium tuberculosis H37Rv and expression in BCG using E. coli-mycobacteria shuttle vector

MPB70 is known to be an immunogenic mycobacterial protein secreted in large amounts from Mycobacterium bovis BCG (BCG) Tokyo. The analogous gene for MPT70 was cloned from Mycobacterium tuberculosis H37Rv which produces this protein in only a small amount. The gene encoding 193 amino acid residues including 30 amino acids for the signal peptide, the promoter-like sequence, and the ribosome-binding site, was completely identical to that of BCG Tokyo. Computer analysis revealed that the carboxy-terminal half of MPT70 was homologous to amino acid sequences of fasciclin I, osteoblast-specific factor 2 (OSF-2), and human transforming growth factor-beta induced gene product (beta IG-H3). Escherichia coli (E. coli) -mycobacteria shuttle vectors containing mpt70 or mpb70 genes 0.7kbp upstream of the 5' end of them were able to be expressed in BCG Pasteur which is a MPB70 low-producer, but the extent of the expression was not that of a high-producer.

Construction of a novel bifunctional biogenic amine receptor by two point mutations of the H2-histamine receptor

BACKGROUND

H2-histamine receptors mediate a wide range of physiological functions extending from stimulation of gastric acid secretion to induction of human promyelocyte differentiation. We have previously cloned the H2-histamine receptor gene and noted that only three amino acids on the receptor were sufficient to define its specificity and selectivity. Despite only modest overall amino acid homology (34% amino acid identity and 57.5% similarity) between the H2-histamine receptor and the receptor for another monoamine, the beta 2-adrenergic receptor, there is remarkable similarity at their critical ligand binding sites. We hypothesized that, if the specificity and selectivity of both receptors are invested in just three amino acids, it should be possible to convert one of the receptors into one that recognizes the ligand of the other by simple mutations at only one or two sites.

MATERIAL AND METHODS

We explored the effect of two single mutations in the fifth transmembrane domain of the H2-histamine receptor, which encompasses the sites that determine H2 selectivity. The canine H2 receptor gene was mutated at Asp186 and Gly187 (Asp186 to Ala186 and Gly187 to Ser187) by oligonuceotide directed mutagenesis. The coding region of both the wild-type and mutated H2 receptors was subcloned into the eukaryotic expression vector, CMVneo, and stably transfected into Hepa cells and L cells. The biological activity of histamine and epinephrine on the expressed receptor was examined by measurement of cellular cAMP production and inositol trisphosphate formation.

RESULTS

Hepa cells transfected with the Ala186-Ser187 mutant H2 receptor demonstrated a biphasic rise in cAMP in response to epinephrine with an early phase (ED50 approximately 10(-11) M) that could be inhibited by both propranolol and cimetidine. Epinephrine also induced IP3 generation in the same cells, a biological response that is characteristic of activation of the wild-type H2 but not of the beta-adrenergic receptor. L cells transfected with the Ala186-Ser187 mutant H2 receptor also responded to epinephrine in a cimetidine and propranolol inhibitable manner.

CONCLUSIONS

We converted the H2-histamine receptor into a bifunctional one that has characteristics of both histamine and adrenergic receptors by two simple mutations. These results support the hypothesis that ligand specificity is determined by only a few key points on a receptor regardless of the structure of the remainder of the molecule. Our studies have important implications on the design of pharmacological agents targeted for action at physiological receptors.

Monitoring of venous blood flow velocity during interhemispheric approach for deep seated lesions

No precise intra-operative monitoring of venous blood flow has yet been developed for neurosurgical procedures. Preservation of the bridging veins is an important issue in order to minimize complications due to disturbances of venous blood flow during an interhemispheric approach. In the present study, venous blood flow velocity was measured in 11 anterior circulation aneurysms. The measurement was performed before brain retraction, during brain retraction and after completion of the procedure without brain retraction. In 6 cases, a bridging vein was dissected completely free from the dura up to its entry into the superior sagittal sinus (SSS group). In 5 cases, dura was cut parallel to the bridging vein so that the vein remained covered by the dura (dura group). Venous blood flow velocity was measured by microvascular Doppler sonography. The results show that venous blood flow can be better preserved during the retraction when the bridging vein remains covered with the dura than if the vein is dissected completely free from the dura.

[Clinical features and factors related to the functional prognosis in Meige's syndrome]

To clarify the factors determining the amelioration of Meige's syndrome, changes of involuntary movements (IVMs) and functional disability, we examined 60 patients with Meige's syndrome during 5 years after the onset. On average, they showed gradual worsening of IVMs for approximately 2.1 years, then the IVMs ameliorated slowly. In many patients, blepharospasm appeared as the first symptom. Subsequent IVMs were seen in vicinity of the muscles of orbicularis oculi. Phasic involuntary contractions changed to tonic ones in some patients. Asynchrony of the IVMs in various facial or neck muscles may be originated from extensive pathological changes and high excitability in the brainstem. The factors determining the amelioration of functional disability are: (1) younger onset, (2) shorter duration from the onset to the period showing the worst symptoms, (3) mild IVMs when the symptoms were the worst, (4) shorter duration from the onset to the beginning of therapy, (5) synchrony of the IVMs between the muscles of orbicularis oculi and other muscles. Methylphenidate, trihexyphenidyl, and ceruletide showed a higher efficiency for IVMs than the other drugs. The drug therapy in Meige's syndrome should be started as early as possible.

Direct approach to intracranial vertebral arteriovenous fistula. Case report

A case of intracranial vertebral arteriovenous fistula is reported. The treatment of choice for this particular vascular malformation is controversial because of the difficulty of management of the intracranial portion of the lesion. We here report a case treated successfully by direct surgery. Its anatomical delineation and operative approach are discussed.

The diversity of T-cell receptor repertoire of peripheral CD4+ lymphocytes in LEC mutant rats

A novel mutant strain of rats, LEC, exhibits an arrest of T-cell maturation from CD4+CD8+ to CD4+CD8- but not the CD4-CD8+ cells in the thymus. Nevertheless, CD4+T cells arise in lymph nodes of LEC rats, implying extrathymic T-cell maturation. We analyzed the variable (V) and junctional region diversity of T-cell receptor (TCR) beta- chains in this population, since several reports have provided evidence that extrathymically matured T cells exhibit a biased expression of the TCR repertoire. CD4+ T cells in LEC rat lymph nodes exhibited a polymorphic V beta gene expression pattern. However, biased V beta gene expression was not identified in peripheral CD4+ T cells of LEC rats when compared with V beta gene expression in their thymocytes. Furthermore, junctional regions of TCR beta chains exhibited a vast diversity created by non-germline- encoded nucleotide (N nucleotide) additions. These results indicate that peripheral CD4+ T cells in LEC rats possess a vast diversity in the TCR repertoire as do thymocytes of the same rat, suggesting that they derive from the thymus.

Antibody responses to Four Corners hantavirus infections in the deer mouse (Peromyscus maniculatus): identification of an immunodominant region of the viral nucleocapsid protein

Antibody responses to Four Corners hantavirus (FCV) infections in the deer mouse (Peromyscus maniculatus) were characterized by using FCV nucleocapsid protein (N), glycoprotein 1 (G1), and glycoprotein 2 (G2) recombinant polypeptides in Western immunoblot assays. Strong immunoglobulin G reactivities to FCV N were observed among FCV-infected wild P. maniculatus mice (n = 34) and in laboratory-infected P. maniculatus mice (n = 11). No immunoglobulin G antibody reactivities to FCV G1 or G2 linear determinants were detected. The strongest N responses were mapped to an amino-proximal segment between amino acids 17 and 59 (QLVTARQKLKDAERAVELDPDDVNKSTLQSRRAAVSALETKLG). FCV N antibodies cross-reacted with recombinant N proteins encoded by Puumala, Seoul, and Hantaan viruses.

Selective localization of gelatinase A, an enzyme degrading beta-amyloid protein, in white matter microglia and in Schwann cells

Gelatinase A is an enzyme capable of cleaving soluble beta-amyloid protein (beta AP), and may function as an alpha-secretase to produce secretory forms of amyloid precursor protein. We examined gelatinase A immunoreactivity in the brains and posterior roots of neurologically normal, lacunar stroke, Alzheimer disease (AD), amyotrophic lateral sclerosis, progressive supranuclear palsy and myasthenia gravis cases. The gelatinase A antibody stained only microglial cells in the white matter in all the brain tissues. In AD brain, the reactive microglia located in the center of classical senile plaques, as well as in other microglial cells in the gray matter, showed no immunoreactivity. Gelatinase A in white matter microglial cells may play a role in preventing local deposition of beta AP. In the posterior root, Schwann cells had positive immunoreactivity. As with other metalloproteases, gelatinase A in Schwann cells may play an antiproliferative role.

Semiquantitative analysis by scanning electron microscopy of cochlear hair cell damage by ototoxic drugs

The ototoxicity of cisplatin and carboplatin in the organ of Corti of the guinea pig was evaluated semiquantitatively. Damage of the stereocilia of outer hair cells (OHCs) observed by scanning electron microscopy (SEM) was classified into normal, grade 1 (10-50% loss of stereocilia), grade 2 (less than 50% remaining stereocilia), or grade 3 (missing stereocilia). The OHCs observed by light microscopy (LM) were classified as remaining or missing cells. Fifty OHCs of each row in the middle part of each turn of the cochlea were counted (a total of 150 cells per turn). Guinea pigs were administered 5 mg/kg of cisplatin or 50 mg/kg of carboplatin intraperitoneally for three consecutive days. In groups 1 and 2, in which both cochlea were fixed in 2.5% glutaraldehyde and 1% osmium tetroxide (OsO4) and observed by SEM, the percentages of damage of the OHC stereocilia were similar in each cochlear turn bilaterally. In group 3, the right cochleae were fixed in OsO4 and observed by phase contrast microscopy as surface preparations. Left cochleae were submitted for SEM observation. Missing and grade 3 cells were observed at similar percentages in each row of each turn. In group 4, succinate dehydrogenase staining was performed in the right cochleae and observed by LM. The degree of damage in the right cochleae was compared with that of the left cochleae which was observed by SEM. On average, the mean numbers of missing cells and cells showing grade 3 damage were similar in each row of each turn. From these similarities of evaluation of ototoxicity at LM and SEM levels, it was concluded that semiquantitative analysis by SEM only is appropriate for the assessment of ototoxicity.

Endoscopic ultrasonographic abnormalities and lower esophageal sphincter function in reflux esophagitis

Endoscopic ultrasonography of the lower esophagus was performed in 25 patients with reflux esophagitis and 13 age-matched controls. Thickening of the esophageal wall and abnormalities of its architecture were detected. As these morphological changes became more extensive, the lower esophageal sphincter pressure and the decrease of sphincter pressure on relaxation were both progressively reduced. There was a significant correlation between morphological abnormalities and lower esophageal function. Our results suggest that inflammatory damage to the muscle layer of the lower esophagus may impair lower esophageal sphincter function further, especially in patients with advanced esophagitis.

Acute onset of diabetic pathological changes in transgenic mice with human aldose reductase cDNA

To investigate the role of human aldose reductase (hAR) in the pathogenesis of diabetic complications, we generated transgenic mice carrying hAR cDNA driven by the murine MHC class I molecule promoter (hAR-Tg). Northern and Western blot analyses and immunoassay of hAR revealed that both hAR mRNA and the protein were expressed in all tissues tested. Thrombosis in renal vessels and fibrinous deposits in Bowman's capsule were observed in 6-week-old hAR-Tg mice fed a normal diet. Ingestion of a 30% glucose diet for 5 days caused sorbitol concentrations in the liver, kidney, and muscle of hAR-Tg mice to be elevated significantly. Seven-week-old hAR-Tg mice fed a 20% galactose diet for 7 days developed cataracts and occlusion of the retinochoroidal vessels, in addition to pathological changes in the kidney. Despite an elevated aldose reductase level in hAR-Tg mice and their intake of an aldose diet, no histopathological changes were found in other tissues, including the brain, lungs, heart, thymus, spleen, intestine, liver, muscle, spinal cord, or sciatic nerve. Results suggest that target organs of diabetic complications, such as the kidney, lens, and retina are sensitive to damage associated with a high level of AR expression, but other organs are not; the susceptibility of each organ to diabetic complications is determined by not only hAR but also other factors.

Violent sleep-related behavior leading to subdural hemorrhage

OBJECTIVE

To polysomnographically determine, using split-screen electroencephalographic-video analysis, the cause of violent sleep-related activity in a patient whose differential diagnosis includes sleep walking (somnambulism), pavor incubus (adult night terrors), nocturnal seizures, psychogenic wandering, and rapid eye movement sleep behavior disorder.

SETTING

The patient was referred to the University of Iowa, Department of Neurology Sleep Disorders Center, Iowa City, from the local community to evaluate a history of violent dreams associated with injury. The subject presented with a subdural hemorrhage that was discovered with magnetic resonance imaging.

OUTCOME

The diagnosis of rapid eye movement sleep behavior disorder was confirmed after a characteristic spell of violent behavior, with an associated dream, was captured polysomnographically.

Molecular cloning of a cell-surface glycoprotein that can potentially discriminate mesothelium from epithelium: its identification as vascular cell adhesion molecule 1

It has long been a practical problem for surgical pathologists to distinguish mesothelium from epithelium in order to make a positive diagnosis of mesothelioma. In this study, we developed a new monoclonal antibody, designated MS-2761 (IgG1, k), against cultured non-neoplastic mesothelial cells. Immunohistochemistry and slot-blot analysis revealed that this monoclonal antibody reacted with 100% (12/12) of benign and malignant mesothelioma tissues and a mesothelioma cell line, but not with 99% (77/78) of epithelial tumour tissues and 97% (33/34) of epithelial tumour cell lines. A gene encoding the cell-surface antigen defined by this monoclonal antibody was isolated from a mesothelial cell cDNA library constructed with a mammalian cell expression vector through transfection of Cos-7 cells and immunoselection by panning. DNA sequencing and a database search revealed that the gene was identical to vascular cell adhesion molecule 1 (VCAM1, also referred to as INCAM110). The prominent VCAM1 transcript in mesothelium was 3.2 kb in size with seven Ig-like domains, in addition to a minor transcripts with six Ig-like domains. This monoclonal antibody potentially discriminates mesothelium from epithelium and may become a tool for differential diagnosis of mesothelioma.

High dose rate brachytherapy for carcinoma of the uterine cervix: comparison of two different fractionation regimens

PURPOSE

There is no consensus as to the best dose-fractionation regimen in high dose rate (HDR) brachytherapy for cervix cancer. Since 1983, two fractionation regimens have been used in different time periods at National Cancer Center Hospital, and their treatment results have been compared in terms of 5-year survival, local control, and complication rate to find the better therapeutic regimen.

METHODS AND MATERIALS

From November 1983 to October 1990, 130 patients with uterine cervix carcinoma were treated with HDR intracavitary brachytherapy using a remote afterloading system. There were 21 Stage Ib patients, 5 Stage IIa, 29 Stage IIb, 2 Stage IIIa, 68 Stage IIIb, and 5 Stage IVa. The median age was 64 years. The median follow-up time was 50 months. Radiotherapy consisted of external beam irradiation to the pelvis (mean dose of 50 Gy), combined with HDR brachytherapy (mean dose of 20 Gy to point A) given 5 Gy per session twice weekly (group A: 54 patients) or 6 Gy once weekly (group B: 76 patients).

RESULTS

The overall 5-year survival was 52% in group A and 72% in group B. Local recurrence rate was 11%, and distant failure rate was 21%, with no difference between the two groups. The complication rate was significantly lower in group B (37%) than in group A (55%). Multivariate analysis has shown that factors affecting survival were stage, brachytherapy dose, and local control status. No factor was predictive of local control, but the external beam radiation dose significantly influenced the risk of complications.

CONCLUSION

The once-weekly HDR intracavitary applications combined with properly adjusted external beam pelvic irradiation is a safe and effective treatment for patients with uterine cervix cancer.

Sequence analysis of the rat jun-D gene

A rat jun-D genomic clone was isolated from a rat liver lambda EMBL3 library. Sequence analysis revealed a high sequence similarity with mouse jun-D, and relatively low similarity with human and chicken jun-D. In both the trans-activation and DNA-binding domains, however, the amino-acid sequences were well conserved among rat, mouse, human and chicken.

Enhanced expression of catalytic subunit isoform PP1 gamma 1 of protein phosphatase type 1 associated with malignancy of osteogenic tumor

The expressions of the three catalytic subunits of protein phosphatase (PP) type 1 and 2A, PP1 alpha, PP1 gamma 1, and PP2AC, were examined in 14 cases of three types of osteogenic tumor using immunohistochemical analysis. The percentage of tumor cells stained positively with antiserum against PP1 catalytic subunit-isoform PP1 gamma 1 was significantly higher in malignant osteogenic tumors than in benign osteogenic tumors. Furthermore, malignant osteogenic tumor showed markedly high S-phase fraction in the cell cycle of tumor cells, as compared to benign osteogenic tumors. These results suggest that PP1 gamma 1 is involved in the accelerated growth of malignant cells in osteogenic tumors.

Hantavirus infection among Rattus norvegicus in Japan

Seroepizootiological study of hantavirus infection among 393 urban rats (Rattus norvegicus) captured in six regions in Japan during the period from 1990 to 1994 was carried out by the indirect fluorescent antibody (IFA) test and Western blot (WB). Fifteen out of 393 (3.8%) rat sera were antibody-positive by IFA, i.e., Tokyo Port (12.8%, 6/47), Shimizu Port (5.7%, 2/35), Otaru Port (1.5%, 1/65) and Nagoya City (3.6%, 6/167). In two other regions, i.e., Kasai Seaside Park and Haneda Airport, rat sera were antibody-negative. One serum with a lower IFA titer, 1:64, from Otaru Port was confirmed to be antibody-positive by WB, while two sera from Shimizu Port (IFA titer, 1:32 and 1:64) were not. In Nagoya City, one out of four sera (IFA titer, 1:32) and one of two sera (IFA titer, 1:64) were also confirmed to be antibody-positive by WB. Continuous hantavirus infection among rats in Tokyo Port, Shimizu Port and Nagoya City and the existence of hantavirus among rats in Otaru Port were demonstrated.

Mapping of the genes for rat endothelin receptor type A (ETAR) and type B (ETBR) to chromosomes 19 and 15 respectively

Chromosomal assignments of the genes for rat endothelin receptor type A (ETAR) and type B (ETBR) were performed by analysing somatic cell hybrid DNAs with the polymerase chain reaction (PCR) using primers specific for rat ETAR and ETBR genes. The genes for ETAR and ETBR were assigned to rat chromosomes 19 and 15 respectively.

Biologic activity of human papillomavirus type 16 E6/E7 cDNA clones isolated from SiHa cervical carcinoma cell line

Three species of E6/E7 cDNAs of human papillomavirus type 16 (HPV16) for the full-length E6/E7 and spliced E6*I/E7 and E6*II/E7 mRNAs were synthesized by reverse transcriptase-(RT-)PCR from RNA of the cervical carcinoma cell line SiHa. Two cDNA mutants carrying point mutations in either a splice donor site or acceptor site within the E6 open reading frame were also constructed. These HPV16 E6/E7 cDNAs were cloned under the SV40 enhancer/promoter and the MMTV LTR to examine the activities of ras-collaborative transformation and induction of cellular DNA synthesis, both of which depend on the E7 gene product. The E6*II/E7 cDNA and two mutated cDNAs deficient in the spliced mRNA transcription showed lower levels of both activities than the full-length E6/E7 and the E6*I/E7 cDNA. The rat cell lines carrying each of the E6/E7 cDNAs contained the E6/E7 mRNA species expected. A small amount of E6*I/E7-sized mRNA was transcribed from a splice-donor site mutant of the E6/E7 cDNA, which turned out to be a transcript derived from a cryptic splice donor site six bases upstream from the conventional site. Among NIH3T3 cells carrying one of the above-mentioned E6/E7 cDNAs, the cells expressing E6*I/E7 mRNA [cells carrying cF(wt) and c*I] produced an amount of E7 protein comparable with those carrying the E7 or E6E7 region. These results suggest that the E6*I/E7 is the mRNA that is important for the efficient expression of E7 product from the HPV16 E6/E7 region.

[Spatial distribution of atrial late potentials on body surface mapping in patients with paroxysmal atrial fibrillation]

We investigated the spatial distribution of atrial late potentials (ALP) in patients with paroxysmal atrial fibrillation (Paf) by use of body surface signal-averaged ECG. The P wave-triggered signal-averaged ECG was recorded in 20 patients with Paf and 34 control patients from precordial 16 unipolar leads (standard V1-V6 and two intercostal spaces below and above V1, V2, V4-V6). The duration (Ad) and number of fragmented deflection (Nf) of filtered P wave were measured on each lead. % Area was also calculated by dividing the area for the last 20 msec by the total area of filtered P wave. The lead having any of a significantly longer Ad, larger Nf and smaller % Area in patients with Paf than the controls was designated as ALP positive lead. ALPs were observed in all other than two intercostal spaces above V5 and V6. This finding suggests that the electrophysiological disparity in the whole atrial muscle might be involved in patients with Paf.

Hyperuricemia in patients with hyperthyroidism due to Graves' disease

The effects of hyperthyroidism on uric acid metabolism were investigated. First, the serum uric acid level was measured in 92 patients with hyperthyroidism due to Graves' disease, eight patients with subacute thyroiditis, six patients with hypothyroidism, and 70 sex- and age-matched controls. Second, the correlation between serum thyroxine (T4) and serum uric acid was obtained in hyperthyroid Graves' disease patients before and during antithyroid drug therapy. Finally, uric acid clearance (CUA) was determined in untreated patients with hyperthyroidism due to Graves' disease. Serum uric acid was significantly elevated in patients with hyperthyroidism, and the elevation correlated well with serum T4 before treatment as a group and during treatment in each patient. A significant elevation of serum uric acid was not present in patients with a transient mild thyrotoxicosis due to subacute thyroiditis. Serum uric acid was significantly decreased in patients with hypothyroidism. Renal excretion of uric acid clearly increased in hyperthyroid patients, and CUA also increased. The increase in CUA corresponded to the increase in renal plasma flow (RPF), which was measured by p-aminohippuric acid clearance. The fractional excretion of uric acid as determined by CUA/glomerular filtration rate (GFR) was similar and within the normal range in hyperthyroid patients and normal controls. A significant inverse correlation between CUA and serum uric acid concentration was present in hyperthyroid patients as in normal controls, indicating that the renal handling of uric acid in the tubule affected uric acid excretion.(ABSTRACT TRUNCATED AT 250 WORDS)