Cathodic isozyme of serum creatine kinase in a case of stomach cancer complicated by disseminated intravascular coagulation

A rare isozyme of serum creatine kinase (CK) migrating cathodic to CK-MM on electrophoresis was found in a 30-year-old male with stomach cancer complicated by disseminated intravascular coagulation leading to massive upper gastrointestinal bleeding and marked anemia. Serum CK activity rose to a maximum of 374 U/l without detectable CK-MB isoenzyme. The patient was also characterized by a marked increase in serum lactate dehydrogenase (all isozymes elevated) and by preferential leakage of mitochondrial aspartate aminotransferase and glutamate dehydrogenase, indicating the presence of extensive tissue damage involving mitochondria. Skeletal muscle mitochondria were considered the most likely source of the additional CK isozyme.

Immunoreactive dog C-peptide level in the pancreatic vein

C-peptide immunoreactivity (CPR) levels were measured in dog superior pancreaticoduodenal vein using synthetic dog C-peptide and its antiserum. The basal CPR level was approximately twice as high as the basal immunoreactive insulin (IRI) level on a molar basis. Glucose (10 mg/kg/min) or arginine (250 mg/kg/min) infusion for 5 min into the superior pancreaticoduodenal artery caused a prompt, parallel increase in IRI and CPR. IRI and CPR were closely equimolar at peak secretions. One bolus administration of synthetic neurotensin (10 microgram/kg) into the same artery produced a mild hyperglycemic response and biphasic IRI and CPR responses at 30 min in the vein. The IRI and CPR increases were closely equimolar during the first phase of secretion, but during the second peak a larger increase was found in CPR than IRI. Upon infusion of synthetic substance P (50 ng/kg/min) for 30 min, IRI and CPR concentrations showed a parallel and closely equimolar fall. These results indicate that insulin and C-peptide were released from beta cells in equimolar concentrations.

Vibrational modes of flavin bound to riboflavin binding protein from egg white. Resonance Raman spectra of lumiflavin and 8-substituted riboflavin

The resonance Raman (RR) spectra of 8-halogenated-riboflavin, 8-demethyl-riboflavin(8-H-RF), 8-amino-riboflavin(8-NH2-RF), 8-methoxy-riboflavin(8-OCH3-RF), lumiflavin, and 3-methyl-lumiflavin were observed. The Raman lines with the highest frequency are at 1624, 1620, and 1615 cm-1 for 8-chloro-riboflavin, 8-bromo-riboflavin, and 8-iodo-riboflavin, respectively. This systematic shift confirms that the 1631 cm-1 line of riboflavin is derived from the benzene part of isoalloxazine. Substitution at the 8-position by an amino or methoxy group, which has a large influence on the electronic structure of isoalloxazine, changes the RR spectrum markedly in comparison with that of 8-halogenated riboflavin. The 1583 cm-1 line of riboflavin, which involves the vibrational displacement of N(5) and C(4a) atoms of isoalloxazine, is shifted to the low frequency side by substitution at the 8-position with an amino or methoxy group. The corresponding line of 8-H-RF, on the contrary, shifts to the high frequency side. The RR spectrum of lumiflavin is very different from that of riboflavin in the range from 1200 to 1300 cm-1. Although the pi-electronic structure is little affected by the substitution at the 10-position, the Raman spectrum of lumiflavin in this region is very sensitive.

Resonance Raman spectra of semiquinone forms of flavins bound to riboflavin binding protein

The resonance Raman (RR) spectra of semiquinones of complexes of riboflavin or 8-methoxyriboflavin (8-OCH3-RF) with riboflavin binding protein (RBP) were observed. The RR spectrum of neutral semiquinone of riboflavin-RBP complex in H2O solution has an intense line at 1617 cm-1, not observed for oxidized riboflavin bound to RBP. The line at 1617 cm-1 does not shift in D2O solution. The absorption spectrum of semiquinone of 8-OCH3-RF bound to RBP has maxima at 586, 396, and 344 nm, and the RR spectrum doublet lines at 1623 and 1615 cm-1. In D2O solution, the 1623 cm-1 line does not shift, but the 1615 cm-1 line shifts to 1604 cm-1. The line around 1620 cm-1 for the flavin semiquinone will be useful in the determination of the redox state of flavin.

Circular dichroism studies on flavoproteins containing covalently bound coenzymes

Absorption and circular dichroism spectra of cholesterol oxidase from Schizophyllum commune and choline oxidase from Alcaligenes sp. were measured and compared. The prosthetic group of cholesterol oxidase is 8 alpha-[N(1)-histidyl]-FAD (1, 2), while that of choline oxidase is 8 alpha-[N(3)-histidyl]-FAD (3). In the CD spectra of the two enzymes in either the oxidized or reduced state, the corresponding bands in the visible region are of approximately the same intensity and shape but of opposite sign. A notable feature in the CD spectra of the two enzymes after light irradiation is the appearance of a CD band in the longer wavelength region (550-650 nm) and the opposite signs of the CD band in this region in the two enzymes. The similarity of the shape and intensity of the CD spectra of the two enzymes suggests that the environments surrounding the flavin moieties are very similar, and the sign reversal of the CD bands suggests that the mutual orientations between the transition moment of flavin and that of its environment differ in the two enzymes.

A study of the absorption, circular dichroism and magnetic circular dichroism spectra of a flavin derivative. The pi-electronic structure of 8-amino-8-demethyl-D-riboflavin

The absorption, CD and MCD spectra of 8-amino-8-demethyl-D-riboflavin, which showed novel spectral properties, were measured in the spectral region from 220 nm to 540 nm and the spectra obtained were analyzed in terms of Gaussian wave number curves (from band I to band X). Semi-empirical calculations of the Pariser-Parr-Pople Hamiltonian were performed to investigate the novel spectral properties and the reactivity at the 5-position. The theoretical results as well as the experimental results showed that the novel spectral properties were a result of amino substitution at the 8-position.

Resonance Raman spectra of carbon-13- and nitrogen-15-labeled riboflavin bound to egg-white flavoprotein

The resonance Raman spectra of [2-13C]-, [4a-13C]-, [4-13C]-8 [10a-13C]-, [2,4,4a, 10a-13C]-, [5-15N]-, [1,3-15N]-, and [1,3,5-15N]riboflavin bound to egg-white proteins were observed for N(3)-H and N(3)-D forms with spontaneous Raman technique by using the 488.0-nm excitation line of an argon ion laser. The fluorescence of riboflavin was quenched by forming a complex with egg-white riboflavin binding protein. The in-plane displacements of the C(2), C(4a), N(1), N(3), and N(5) atoms during each Raman active vibration were calculated from the observed isotopic frequency shifts. The 1252-cm-1 mode of the N(3)-H form was found to involve large vibrational displacements of the C(2) and N(3) atoms and to be strongly coupled with the N(3)-H bending mode. This line can be used as an indicator for state of N(3)-H...protein interaction. The 1584-cm-1 mode, which is known to be resonance-enhanced upon excitation near the 370-nm absorption band, was accompanied by the displacement of the N(5) atom in particular. The 1355-cm-1 mode was most strongly resonance-enhanced by the 450-nm absorption band and involved the displacements of all carbon atoms of ring III. Both lines can be used as structure probes for elucidating the structure of electronically excited states of isoalloxazine.

A study of flavin-protein and flavoprotein-ligand interactions. Binding aspects and spectral properties of D-amino acid oxidase and riboflavin binding protein

To study flavin-protein and flavoprotein-ligand interaction, the absorption, CD and MCD spectra of riboflavin, FAD, roseoflavin, the complexes of riboflavin and roseoflavin with riboflavin binding protein(RBP),D-amino acid oxidase(D-AO) and its complexes with ligands were observed in the spectral region of 310-600 nm and the binding properties of D-AO with di-substituted benzoate derivatives and of RBP with roseoflavin were also measured. The dimer of D-amino acid oxidase has a higher affinity for di-substituted benzoate derivatives than the monomer. The change in the absorption of FAD in D-AO caused by the binding of the first ligand to the dimer, which can bind two ligands, was similar to that caused by the binding of the second ligand. Roseoflavin could bind to RBP in a 1 : 1 ratio and the dissociation constant was 3.8 x 10(-8)M. The protein fluorescence of RBP was quenched by about 86% due to complex formation with roseoflavin. The MCD spectra showed similar patterns for all molecular complexes of riboflavin and FAD, with two negative extrema of ellipticity which probably correspond to the Faraday B-term, but the Faraday A-term could not be observed, suggesting that there was no degeneracy in the excited state of flavins. It is also suggested, based on a comparison of the absorption, CD and MCD spectra, that the vibronic structure of flavin was modified differently by each flavin-protein or flavoprotein-ligand interaction. Comparison of the absorption, CD and MCD spectra(310-600 nm) for roseoflavin and the roseoflavin-RBP complex revealed that there were five spectral components around 320, 340, 400, 500, and 550 nm in roseoflavin.

Resonance Raman spectra of riboflavin and its derivatives in the bound state with egg riboflavin binding proteins

The resonance Raman spectra of riboflavin (RF) and its derivatives, including 3-deuterated (3-D RF), 3-methyl (3-CH3 RF), 3-carboxymethyl (3-CH2COOH RF), and 7,8-dichlororiboflavins (7,8-Cl RF), in H2O and D2O were observed in the 700-1700 cm-1 region. The fluorescence problem of riboflavin was overcome by complex formation of riboflavin with riboflavin binding proteins. The observed frequencies of Raman lines of RF are in good agreement with those of glucose oxidase obtained by Spiro et al. by the resonance CARS method, although the present spectral range is extended to much lower frequency with a higher signal-to-noise ratio than that for glucose oxidase. The observed Raman lines were assigned to the individual ring modes of isoalloxazine on the basis of the Raman spectra of appropriate model compounds such as uracil, pyrazine, and o-xylene. The 1253 cm-1 line of RF was shifted to ca. 1300 cm-1 for 3-D RF, 3-CH3 RF, and 3-CH2COOH RF, and accordingly can be assigned to the CN stretching mode of Ring III. The 1632 cm-1 line of RF was shifted for 7,8-Cl RF and was assigned to a Ring I mode. No Raman line mainly due to C = O stretching mode was observed in the present resonance Raman spectra.

Potential endocrine effects of hypothalamic peptide "neurotensin" on pancreas in dogs

Effects of synthetic neurotensin on the endocrine pancreas were studied in nine normal and six hypophysectomized (10th to 14th day post-hypophysectomy) dogs. Synthetic neurotensin was administered into the superior pancreaticoduodenal artery, and plasma insulin and glucagon concentrations were measured radioimmunologically. In normal dogs, ten microgram/kg neurotensin administration brought about a mild hyperglycemic response and sharp and rapid increase of plasma insulin and glucagon concentrations in the superior pancreaticoduodenal vein. A biphasic insulin response was noted in the pancreatic vein. The results suggest that a large dose of neurotensin acts directly on the endocrine pancreas causing secretion of these hormones. In hypophysectomized dogs, basal levels of plasma insulin and glucagon were decreased and neurotensin had little effect on the endocrine pancreas even with the administration of a large dose.

Lipoatrophic diabetes. Report of a case

The female patient initially showed the acquired type of total lipoatrophy at about 8 years of age. At 12 years of age, the onset of diabetes mellitus was speculated from advanced pyodermia and dedentition. At 29 years of age, glucosuria was found, and she developed proteinuria, ascites, and pretibial edema. The physical examination revealed: hepatosplenomegaly, complete absence of subcutanous fat, cutaneous xanthomas, and emaciated facies with pronounced zygomatic arches. Diabetic retinopathy was revealed in the ophthalmological examination, and nephropathy was evident in renal biopsy specimens. She also had peripheral diabetic neuropathy. No adipose tissue was found in the mesenterium under peritoneoscopy. The hepatic biopsy specimen revealed advanced portal liver cirrhosis. Laboratory findings included: hyperlipidemia, elevation of BMR without evidence of hyperthyroidism, impaired renal function, and undetected anti-insulin antibodies and anti-insulin antibodies. Endocrinological examinations revealed normal value, except for an impaired hGH response in the arginine test. C-peptide immunoreactivity was high. Her condition was fairly well controlled by 140 units of insulin injection daily.

The effects of xenopsin of endocrine pancreas and gastric antrum in dogs

Effects of synthetic xenopsin on endocrine pancreas and gastric antrum in anesthetized dogs were studied. Synthetic xenopsin was administered into the superior pancreaticoduodenal artery and plasma insulin, glucagon and gastrin in the superior pancreaticoduodenal vein and gastrin in the right gastroepiploic vein were measured radioimmunologically. Administration of 10 microgram of xenopsin per kg of body weight brought about a hyperglycemic response and rapid and sharp elevations of the hormones in the pancreatic vein. Plasma gastrin level in the gastric vein also showed an immediate and sharp increase following xenopsin administration. Xenopsin appeared more potent inducer of the glucagon. It is concluded that xenopsin acts directly on endocrine pancreas and gastric antrum to secrete their hormones.

A fluorescence study of egg white riboflavin-binding protein

1. Denaturation of riboflavin-binding protein (RBP) by guanidine hydrochloride (Gu-HCl) was investigated by measruing the fluorescence of the protein. The denaturation-renaturation processes of RBP by Gu-HCl were fully reversible. The apo-RBP fluorescence had an emission maximum at 343 nm in the absence of Gu-HCl, and at 350 nm in the presence of 4M Gu-HCl, which completely denatured the protein. The relative fluorescence yield of apo-RBP in the presence of 4 M Gu-HCl was about 170% of that in the absence of Gu-HCl. The affinity of native apo-RBP for riboflavin was very strong, while riboflavin was not bound to the denatured form. The equilibrium system of apo-RBP and riboflavin in solutions containing Gu-HCl at various concentrations was analyzed by measuring riboflavin fluorescence. 2. The quenching of apo-RBP fluorescence, probably the fluorescence of tryptophanyl residues, by iodide anions and cesium cations was measured. The fluorescence of apo-RBP in the presence of 4 M Gu-HCl was quenched considerably by iodide and cesium, and Stern-Volmer plots were linear. However, the fluorescence of native apo-RBP was scarcely quenched by iodide or cesium. This suggested that tryptophanyl residues buried inside apo-RBP were responsible for most of the tryptophanyl fluorescence of native apo-RBP.

Association-dissociation of the flavoprotein hog kidney D-amino acid oxidase. Determination of the monomer-dimer equilibrium constant and the energetics of subunit association

The enzyme concentration dependence of spectrophotometric titrations of hog kidney D-amino acid oxidase [EC 1.4.3.3] with p-aminobenzoate was studied. The monomer-dimer equilibrium constant of the oxidized holoenzyme at 25 degrees C was estimated to be 7 X 10(5)M-1 at pH 7.5 and 4X 10(6)M-1 at pH 8.3. The energetics of subunit association are discussed.

Effect of halide anions on the binding of FAD to D-amino acid oxidase and the tryptophanyl fluorescence of the apoenzyme

The quenching of tryptophanyl fluorescence of native and denatured D-amino acid oxidase from hog kidney was measured. About 60% of the tryptophanyl fluorescence of the native apoenzyme was quenched by iodide at pH 8.3, and 25 degrees C. All of the tryptophanyl fluorescence of the apoenzyme in 6 M guanidine hydrochloride was quenched. The tryptophanyl fluorescence quenching of the holoenzyme by 1-methyl nicotinamide chloride was low in comparison with that of the apoenzyme. These results of the quenching experiments are discussed based on the intermolecular collision quenching mechanism. By measuring the fluorescence intensities of the tryptophanyl residues and FAD of the holoenzyme solution, and the fluorescence polarization of the holoenzyme solution containing halide anions such as iodide, bromide, chloride, or fluoride, we found that FAD dissociates from the holoenzyme in the presence of iodide, bromide, or chloride, and the ability to dissociate FAD from the holoenzyme decreases in order iodide, bromide, and chloride. However, fluoride seems to enhance the association reaction of FAD with the apoenzyme. These results were consistent with the visible absorption spectra and derivative spectra of free FAD and the holoenzyme in the presence and absence of halide anions.

Successful immunosuppressive therapy in insulin resistant diabetes caused by anti-insulin receptor autoantibodies

A 45-year-old, non-obese female patient with no previous history of insulin administration was found to have extreme insulin resistance and abnormally high plasma immunoreactive insulin in the absence of anti-insulin antibodies in the serum. Clinically, there was no ketonuria. The patient also had evidence of Sjogren's syndrome with several immunologic features including hypergammaglobulinemia, positive antinuclear antibodies, accelerated erythrocyte sedimentation rate and leukopenia. Plasma pancreatic glucagon and C-peptide were elevated, but other endocrinologic abnormalties were not present. In this patient the insulin resistance appeared to be due to anti-insulin receptor antibodies which could be detected even in 1:500 dilution of serum. Immunosuppressive therapy with prednisolone and cyclophosphamide resulted in a decreased level of serum gamma globulin and a concomitant decrease of blood glucose level. After immunosuppressive therapy for eight months, the diabetic syndrome disappeared completely and anti-receptor antibodies in the serum were no longer detectable. Furthermore, insulin sensitivity returned to normal. However, the patient's glucose tolerance deteriorated after the temporary termination of cyclophosphamide treatment and the lowering of prednisolone dosage.

pH dependence of catalysis of the monomer of hog kidney D-amino acid oxidase

The role of aortic arch angiography in the evaluation of cerebral ischemic disease is not well defined. In an attempt to develop guidelines for its optimal use, a prospective study of 100 patients with carotid distribution ischemic events was undertaken. Each patient underwent bilateral selective carotid angiography followed by arch aortography. In only two of the cases did the arch examination affect patient management. In the other individuals, the arch study either added no clinically useful information (69), or demonstrated abnormalities that did not affect patient care (29). The findings of this study support the use of arch aortography only in those patients who have surgical lesions demonstrated by the selective carotid examinations.