Arginine 485 of human serum albumin interacts with the benzophenone moiety of ketoprofen in the binding pocket of subdomain III A and III B

Arylpropionic acid nonsteroidal anti-inflammatory drusg (NSAIDs) primarily bind to subdomain III A (site II) of human serum albumin (HSA). Ketoprofen (KP), an arylpropionic acid that contains a photoreactive benzophenone moiety, was used to photolabel the binding region of site II. LC/Q-TOF mass spectrometry determination revealed that R485 was the amino acid residue that formed covalent adduct with the benzophenone moiety of KP. Point mutation of arginine 485 to alanine showed a slight decrease in the overall binding percentage of KP when compared to that of native HSA. The induced circular dichroism spectral data of KP with both R485A and native albumin confirmed the photolabeling findings. Interestingly, an increase in the extent of [14C]KP covalent adduct formation with the 11.6 kDa peptide derived from subdomain IIB-IIIA was observed for R485A. In contrast, mutation of arginine 410 caused a significant reduction of binding percentage, confirming the importance of this residue in high affinity binding of arylpropionic acid derivatives. This may indicate that while KP's carboxylate interacts electrostatically with arginine 410, the benzophenone moiety may have swung away from helix 6 in the absence of arginine 485. In this study, photolabeling of native and mutants albumins, R485A and R410C with [14C]KP confirmed that R485 involved in the non-electrostatic interaction with the benzophenone moiety of KP, but not vital to hold KP in the binding pocket of subdomain IIIA.

Distribution and species composition of juvenile and adult scombropids (Teleostei, Scombropidae) in Japanese coastal waters

Two scombropid fishes, Scombrops boops and Scombrops gilberti, are closely related and commercially important species in Japan. These species are often confused in commercial markets because of their morphological similarity. In this study, scombropid specimens collected from various Japanese coastal waters were subjected to polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis and phylogenetic analysis of the 16S rRNA gene in mitochondrial DNA. These analyses showed that all the scombropid specimens collected from localities in the Sea of Japan were identified as S. boops, whereas those from the Pacific Ocean included two species, S. boops and S. gilberti. Almost all juvenile (<200 mm standard body length, S(L)) S. gilberti originated from the Pacific coastal waters of the northern Japan, whereas adults (>400 mm S(L)) were found only in deep water off the Izu Peninsula to the Izu Islands. This suggests that S. gilberti might migrate extensively during its life cycle. In addition, differences in the number of specimens and the distribution between the two species suggest that S. gilberti is less abundant than S. boops in Japanese waters.

Nanoscale hydrophobic interaction and nanobubble nucleation

We report large-scale atomistic simulation of midrange nanoscale hydrophobic interaction, manifested by the nucleation of nanobubble between nanometer-sized hydrophobes at constrained equilibrium. When the length scale of the hydrophobes is greater than 2 nm, the nanobubble formation shows hysteresis behavior resembling the first-order transition. Calculation of the potential of mean force versus interhydrophobe distance provides a quantitative measure of the strength of the nanoscale hydrophobic interaction.

Homozygosity and linkage disequilibrium mapping of autosomal recessive distal myopathy (Nonaka distal myopathy)

Autosomal recessive distal myopathy or Nonaka distal myopathy (NM) is characterized by its unique distribution of muscular weakness and wasting. The patients present with spared quadriceps muscles even in a late stage of the disease. The hamstring and tibialis anterior muscles are affected severely in early adulthood. We have localized the NM gene to the region between markers D9S319 and D9S276 on chromosome 9 by linkage analysis. To further refine the localization of the NM gene, we conducted homozygosity and linkage disequilibrium analysis for 14 patients from 11 NM families using 18 polymorphic markers. All of the patients from consanguineous NM families were found to be homozygous for six markers located within the region between markers D9S2178 and D9S1859. We also provided evidence for significant allelic associations between the NM region and five marker loci. Examination of the haplotype analysis identified a predominant ancestral haplotype comprising the associated alleles 199-160-154-109 (marker order: D9S2179-D9S2180-D9S2181-D9S1804), present in 60% of NM chromosomes and in 0% of parent chromosomes. On the basis of the data obtained in this study, the majority of NM chromosomes were derived from a single ancestral founder, and the NM gene is probably located within the 1.5-Mb region between markers D9S2178 and D9S1791.

In vitro and in vivo properties of recombinant human serum albumin from Pichia pastoris purified by a method of short processing time

PURPOSE

Recombinant human serum albumin (rHSA), secreted by a Pichia pastoris expression system, was purified by a fast and efficient method, the essential feature of which is strong but reversible binding of the protein to Blue Sepharose. The structural characteristics, stability, and ligand-binding properties of the resulting protein were examined, and pre-clinical studies were performed.

METHODS

Protein structure was investigated by amino acid sequencing, sodium polyacrylamide gel electrophoresis, CD spectroscopy and chromatography. Stability was examined by denaturation by guanidine hydrochloride and by calorimetry, and ligand binding was studied by ultrafiltration. Rat experiments were performed with 125I-labeled albumin.

RESULTS

Far-ultraviolet and near-ultraviolet CD spectra of rHSA were identical to those of human serum albumin isolated from serum (HSA). Mercaptalbumin and non-mercaptalbumin were separated by high-performance liquid chromatography using an N-methylpyridinium polymer-based column. 60% of rHSA existed as mercaptalbumin, a content that is higher than that of a commercial preparation of HSA. Fatty acids, N-acetyl-L-tryptophan and pasteurization had similar effects on the conformational stability of rHSA and HSA. Stereoselective ligand-binding properties (warfarin, phenprocoumon, pranoprofen and ibuprofen) of rHSA were the same as those of HSA. The effect of the neutral to base transition on warfarin (site I-ligand) and dansylsarcosine (site II-ligand) binding to rHSA was also similar to HSA. In vivo studies showed comparable half-lives, excretion and tissue distributions of the two albumin preparations.

CONCLUSION

The present yeast expression system and purification procedure result in rHSA with structural and functional properties very similar to those of HSA.

Stability of a cisplatin-chondroitin sulfate A complex in plasma and kidney in terms of protein binding

To assess the stability of a cisplatin (CDDP) complex prepared with chondroitin sulfate A (CSA) relative to protein binding in the circulation and kidney, a trichloroacetic acid (TCA) precipitation method was developed to measure the protein-unbound species of CDDP and the CDDP-CSA complex in plasma and kidney homogenates. The total and unbound drug concentrations were determined up to 3 h following a 2 mg/kg bolus injection of CDDP or CDDP-CSA complex to rats. The stability against plasma binding was evaluated by a determination of the area under concentration-time curve from time 0 to infinite time (AUC(0-infinity)); the ratio of unbound drug AUC(0-infinity) to total drug AUC(0-infinity) was employed to estimate the availability of the unbound drug in the circulation. The results showed that a competitive reaction to platinum existed between plasma protein and the CDDP-CSA complex, but the complex accounted for more than 60% of the protein-unbound species for a dosage, compared to 30% obtained by an administration of uncomplexed CDDP. The tissue binding kinetics in kidney for CDDP and the CDDP-CSA complex was investigated by the use of homogenates. The binding rate constants of CDDP and CDDP-CSA in a kidney homogenate were 0.0040 min(-1) and 0.0014 min(-1), respectively. The results indicate that the CDDP-CSA complex could effectively retard the binding of CDDP to protein in the kidney. These data provide evidence that endogenous protein is able to compete for platinum from the CDDP-CSA complex, but the complex effectively retarded the protein binding reaction with CDDP in plasma and kidney as compared to native CDDP, which has the potential for reducing the accumulation of CDDP in plasma and kidney.

Mutations of the notch3 gene in non-caucasian patients with suspected CADASIL syndrome

The Notch3 gene has been recently identified as a causative gene for cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL). To investigate the genetic contribution of Notch mutations in familial cases with vascular leukoencephalopathy, we screened 13 patients from 11 unrelated families, which were selected on the basis of magnetic resonance imaging findings and positive family history. We identified three different missense mutations in 5 patients from 4 families. Two (Arg90Cys and Arg133Cys) are the same as previously reported in Caucasian patients, the other (Cys174Phe) is a novel mutation causing a loss of a cysteine in epidermal-growth-factor-like repeats of Notch3. These data indicate that the CADASIL Notch3 mutations were found in approximately 35% of familial cases with leukoencephalopathy, suggesting genetic heterogeneity of the disease.

Evidence for the presence of keratinocyte growth factor (KGF) in human ovarian follicles

The presence of keratinocyte growth factor (KGF) in human follicular fluid (FF) was investigated in a total of 145 FFs obtained during oocyte retrieval for in vitro fertilization (IVF) from 29 patients with no apparent endocrine disorders. The concentrations of KGF, estradiol, progesterone, testosterone and human chorionic gonadotropin (hCG) in FF were measured by enzyme-linked immunosorbent assay. FF samples contained relatively higher amounts of KGF (2194+/-87 pg/ml), whereas its concentrations in serum were below assay limit (<31.2 pg/ml). Concentrations of KGF in FF were positively correlated with both progesterone (r=0.311, p<0.0005) and testosterone (r=0.230, p<0.01) concentrations in FF. However, KGF concentrations were not significantly correlated with estradiol and hCG concentrations. KGF in FF was detected as a broad band (26-29 kD) by immunoblotting, the size being reduced by 7kD after N-glycosidase treatment. In an in vitro experiment, KGF suppressed the basal and hCG-stimulated progesterone production by cultured human luteinized granulosa cells. summary, we demonstrated the presence of KGF in human ovarian follicles, suggesting its possible role as a local factor in regulating human ovarian functions.

Interaction mechanism between indoxyl sulfate, a typical uremic toxin bound to site II, and ligands bound to site I of human serum albumin

PURPOSE

The study was performed for clarifying the mechanism of interaction between indoxyl sulfate (IS), a typical uremic toxin bound to site II, and site I-ligands when bound to human serum albumin (HSA). The effect of the N to B transition on the interactions was also examined.

METHODS

Quantitative investigation of the relations between ligands bound to HSA was performed by equilibrium dialysis, and the binding data were analyzed on the basis of a theoretical model for simultaneous binding of two ligands.

RESULTS

The high-affinity binding constants for the site I-ligands warfarin (WF) and dansyl-L-asparagine (DNSA) increased with increasing pH, whereas those for the site II-ligands IS and dansylsarcosine (DNSS) were hardly affected by pH. Mutual displacement experiments showed that even though IS binds to site II it influenced binding of DNSA at the azapropazone binding area in site I. By contrast, it is unlikely that IS affects the WF binding area of site I. Furthermore, pH-profiles showed that the interaction between IS and DNSA was very sensitive to the N to B transition: "competitive-like" strong allosteric regulation was observed for binding of the two ligands to the N conformer (pH 6.5), whereas in the B conformation (pH 8.5) binding of these molecules was nearly "independent".

CONCLUSIONS

The present data provide useful information for elucidating a potential mechanism of interaction between drugs and endogenous substances including uremic toxins.

[CADASIL: clinical analysis of CADASIL and CADASIL-like disorders in Japan]

To clarify the characteristics of CADASIL in Japan, we performed clinical and genetic investigations for six patients from 5 Japanese families diagnosed as CADASIL. We identified that the onset of focal neurologic deficits ranged from 38 to 63 years old (mean 49 +/- 9.4 yrs) and the occurrence rates of main neurologic symptoms and signs were 1/6 for migraine, 3/6 for recurrent stroke episodes, 6/6 for dementia, and 4/6 for pseudobulbar palsy. The marked narrowing of retinal arteries were observed in 3/6. The notch 3 mutations were all found in exon 4. Although other several families shared similar phenotype of CADASIL, there were no deposition of granular osmiophilic materials within the basal lamina of smooth muscle cells in the arterioles of biopsied muscle and no mutations in the cording regions of notch 3 gene. We investigated prospectively the incidence of CADASIL and CADASIL-like disease in Kumamoto district from 1999 to 2000. One thousand and thirty four patients with stroke were hospitalized in 6 hospitals which have stroke care unit. Among them, 7 patients fulfilled the criteria that were less than 60 years old, lacunar strokes and/or TIA, presence of a family history, and no risk factors such as hypertension, diabetes mellitus, and hyperlipidemia. One of seven patients was diagnosed as CADASIL by DNA analysis. It was suspected the incidences of CADASIL and CADASIL-like disease were not so rare in Japan.

Functional mapping against Escherichia coli for the broad-spectrum antimicrobial peptide, thanatin, based on an in vivo monitoring assay system

Previously, we established for the first time an in vivo monitoring assay system conjugated with random mutagenesis in order to study the structure-function relationship of the antimicrobial peptide, apidaecin [Taguchi et al. (1996) Appl. Environ. Microbiol. 62, 4652-4655]. In the present study, this methodology was used to carry out the functional mapping of a second target, thanatin, a 21-residue peptide that exhibits the broadest antimicrobial spectrum so far observed among insect defense peptides [Fehlbaum et al. (1996) Proc. Natl. Acad. Sci. USA 93, 1221-1225]. First, a synthetic gene encoding thanatin was expressed in a fused form with Streptomyces protease inhibitor protein, SSI, under the control of tac promoter in Escherichia coli JM109. Expression of the thanatin-fused protein was found to depend on the concentration of the transcriptional inducer, isopropyl-beta-D-thio-galactopyranoside (IPTG), and to parallel the degree of growth inhibition of the transformant cells. When a PCR random mutation was introduced into the structural gene for thanatin, diminished growth inhibition of the IPTG-induced transformed cells was mostly observed in variants as measured by colony size (plate assay) or optical density (liquid assay) in comparison with the wild-type peptide, possibly depending on the decreased antimicrobial activity of each variant. Next, wild-type thanatin and three variants screened by the in vivo assay, two singly mutated proteins (C11Y and M21R) and one doubly mutated protein (K17R/R20G), were stably overproduced with a fusion partner protein resulting in the efficient formation of inclusion bodies in E. coli BL21(DE3). The products were isolated in large amounts (yield 30%) from the fused protein by successive chemical and enzymatic digestions at the protein fusion linker site. Anti-E. coli JM109 activities, judged by minimum inhibitory concentration, of the purified peptides were in good agreement with those estimated semi-quantitatively by the in vivo assay. Based on the NMR solution structure and molecular dynamics, the structure-function relationship of thanatin is discussed by comparing the functional mapping data obtained here with the previous biochemical data. The functional mapping newly suggests the importance of a hydrogen bonding network formed within the C-terminal loop joining the beta-strands arranged antiparallel to one another that are supposed to be crutial for exhibiting anti-E. coli activity.

Evidence for the presence of angiogenin in human follicular fluid and the up-regulation of its production by human chorionic gonadotropin and hypoxia

Angiogenesis is an essential event during the development of the ovarian follicle and ensuing formation of the corpus luteum. We investigated the presence of angiogenin, a potent inducer of angiogenesis, and the regulatory mechanisms of its production in the human ovary. Follicular fluid (FF) and granulosa cells (GCs) were collected from women undergoing in vitro fertilization and embryo transfer. The presence of angiogenin in FF and GCs was demonstrated by Western blot analysis. The production of angiogenin by cultured GCs was stimulated with the addition of human CG or cAMP or under the hypoxic milieu. Concentrations of angiogenin in FF from an individual follicle were positively correlated with those of progesterone, but not estradiol and testosterone. Given the presence of angiogenin in FF and up-regulation of its production by human CG and hypoxia, it seems logical to assume that angiogenin may play a role as a local angiogenic factor in the human ovary.

Arg133Cys mutation of Notch3 in two unrelated Japanese families with CADASIL

OBJECTIVE

More than 80 unrelated, but all Caucasian, patients with cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL), originating from various communities around the world, have been molecularly identified. To clarify the occurrence of CADASIL in Orientals, we investigated Japanese families presenting as CADASIL.

METHODS

We performed the PCR-SSCP and sequence analyses using genomic DNA, isolated from venous blood of participants under informed consent.

PATIENTS

We identified two unrelated Japanese families with CADASIL, including 5 affected members through 2 generations.

RESULTS

Each of the affected individuals developed recurrent strokes without risk factors resulting in progressive dementia, pseudobulbar palsy, and gait disturbances which started after the fifth decade of life. Although affected individuals had no vascular risk factors, they showed various degrees of narrowing of retinal arteries. Their MRI/CTs showed characteristics of the disease; bilateral small infarcts in the thalamus, basal ganglia, brain stem, and deep white matter in addition to the findings of leukoaraiosis. On SPECT imaging, there was severe hypoperfusion in the cortex as well as in the white matter. Ultrastructural studies revealed an abnormal deposition of granular osmiophilic materials (GOM) within the basal lamina of pericytes in muscular capillaries. On PCR-SSCP and sequence analyses, a heterozygous Arg133Cys mutation was present, in the affected individuals, in the exon 4 of Notch3 gene which is the hot spot region for CADASIL mutations in Caucasian families. None of the non-affected members nor the 50 Japanese normal controls revealed this mutation.

CONCLUSION

Thus, our results confirm that CADASIL is a geographically widespread disorder caused by a Notch3 mutation.

Characterization of a binding site of UCN-01, a novel anticancer drug on alpha-acid glycoprotein

The binding site of 7-hydroxystaurosporine (UCN-01) on alpha-acid glycoprotein (AGP) was studied by fluorescence and ultracentrifugation experiments. Three ligands, propranolol, warfarin and progesterone were employed as marker ligands and quinaldine red was employed as a fluorescent probe. The presence of UCN-01, pro- pranolol, warfarin and progesterone resulted in a significant quenching of the fluorescence of quinaldine red, when bound to AGP, depending upon the potency of the binding to AGP. The construction of Klotz plots indicated that the displacement effects of propranolol, warfarin and progesterone on UCN-01-AGP binding were competitive in nature. These data suggest that the binding site of UCN-01 on the AGP partly overlaps the binding site for basic drugs, acidic drugs, as well as steroid hormones.

[A family of hereditary neuropathy with liability to pressure palsies with a proband who developed right and left foot drop successively following the left radial nerve palsy]

A 41-year-old man developed multifocal mononeuropathies manifesting right and left foot drop successively, following the left radial nerve palsy as an initial symptom. Based on the neurological findings and the results of the genetic study of peripheral myelin protein (PMP) 22 gene and the histological study of the sural nerve on biopsy, the diagnosis of hereditary neuropathy with liability to pressure palsies (HNPP) was made. Two asymptomatic carriers were found among his family members based on the genetic study. The diagnosis of HNPP can be definitely established by the genetic study and this disease is relatively rare. In this report it is important to note that there are a few patients who show radial nerve palsy as an initial symptom, that we should carefully study the family members to obtain the prevalence of HNPP because asymptomatic carriers may be present, and that the carriers should be advised to avoid strenuous exercises and works which may produce excessive extension or compression of nerve trunks with the subsequent development of clinical symptoms.

Evidence for the presence of hepatocyte growth factor expression in human ovarian follicles

The presence of hepatocyte growth factor (HGF) in follicular fluid (FF) relative to concentrations of sex steroid hormones and human chorionic gonadotrophin (HCG) was investigated. A total of 69 FF samples were obtained during oocyte retrieval for in-vitro fertilization (IVF) from 11 patients with no apparent endocrine disorders. The concentrations of HGF, oestradiol, progesterone, HCG and testosterone in FF samples were measured by enzyme-linked immunosorbent assay. Transcription of HGF and its receptor, c-met, was detected by reverse transcription-polymerase chain reaction (RT-PCR). Human FF samples contained approximately 90-fold higher amounts of HGF (24.2 +/- 1.2 ng/ml), compared with those of serum (0. 28 +/- 0.04 ng/ml). Concentrations of HGF in FF were positively correlated with those of progesterone (r = 0.649, P < 0.0001) and HCG (r = 0.264, P = 0.026) concentrations in FF. However, HGF concentrations were not significantly correlated with oestradiol and testosterone. HGF in FF was detected by Western blotting, as a single 90 kDa band, corresponding to a single chain form. Additionally, mRNA for both HGF and its receptor were detected in a crude granulosa cell preparation from the pre-ovulatory follicles. These findings suggest that HGF is produced locally in human ovarian follicles and may have a physiological role as an autocrine/paracrine factor.

Hepatocyte growth factor concentrations are elevated in peritoneal fluid of women with endometriosis

The concentrations of hepatocyte growth factor (HGF) in peritoneal fluid (PF) from women with endometriosis (n = 36) and without endometriosis (n = 40) were measured. All of the PF samples examined contained detectable concentrations of HGF. The HGF concentrations in PF from women with stage III/IV endometriosis (0.906 ng/ml, 0. 561-1.185; median, interquartile range) were significantly higher (P < 0.0001) than those from women without endometriosis (0.315 ng/ml, 0.251-0.472). The HGF concentrations from women with stage I/II endometriosis (0.417 ng/ml, 0.310-1.023) appeared to be intermediate. There were no apparent variations detected among the HGF concentrations in women in the follicular or luteal phases regardless of the presence of endometriosis. Interestingly, HGF concentrations in PF from women on gonadotrophin releasing hormone analogues, independent of the presence of endometriosis, were comparable with those from untreated women. Given the known mitogenic property of HGF in human endometrial cells, these results suggest that HGF might play a role in the progression of endometriosis.

[A case of hereditary ceruloplasmin deficiency with hemosiderosis]

We report a 49-year-old female with hereditary ceruloplasmin deficiency with hemosiderosis. There was a family history of the same symptoms; her brother showed hypoceruloplasminemia and decrease of the serum copper content. On physical examinations, dementia, dysarthria, downbeat nystagmus, sensorineural hearing disturbance, orthostatic hypotension, retinitis pigmentosa, diffuse goiter, and cerebellar ataxia were noted. Laboratory examinations disclosed leukopenia, diabetes mellitus, hypothyroidism, decrease of copper content in the serum and urine. Serum ferritin concentration was remarkably increased. Serum ceruloplasmin could not be detected. Biopsy of the liver showed that iron content in the liver was increased. On MRI study, dentate nucleus of the cerebellum, basal ganglia, and the liver showed low intensity in both T1 and T2 weighted images. A nonsense mutation in the ceruloplasmin gene was found in this patient. Systemic iron deposition and tissue damage were considered as caused by deficiency of function of ceruloplasmin as ferroxidase. To our knowledge, the characteristic combination of the clinical signs in this patient has not been reported.

Specificity of omega-conotoxin MVIIC-binding and -blocking calcium channel antibodies in Lambert-Eaton myasthenic syndrome

An immunoprecipitation assay was used to measure omega-conotoxin MVIIC (P/Q-type) binding and blocking calcium channel antibodies in 67 patients with Lambert-Eaton myasthenic syndrome (LEMS) and in a large control population. We first showed the presence of omega-conotoxin MVIIC-blocking antibody in LEMS patients. Binding antibodies were detected in 55 of 67 (82.1%) LEMS patients and in 2 of 296 (0.7%) controls. In contrast, blocking antibodies were positive in 14 of 67 (20.9%) LEMS patients and 8 of 171 (4.7%) controls. No LEMS patient had negative binding antibodies and positive blocking antibodies. The immunoprecipitation assay detected no antibodies against the whole P/Q-type calcium channel in either the paraneoplastic cerebellar degeneration or the amyotrophic lateral sclerosis sera. Neither the omega-conotoxin MVIIC-binding nor the -blocking calcium channel antibodies were correlated with clinical severity across the individuals, but longitudinal studies of some LEMS patients showed an inverse relation between binding antibody titre and disease severity. We concluded that the 125I-omega-conotoxin MVIIC assay for anti-P/Q-type voltage-gated calcium channel antibodies is highly specific for LEMS and that this sensitive binding antibody assay could be more valuable than the blocking antibody assay in the diagnosis of LEMS.

Differential effect of exogenous human chorionic gonadotrophin on progesterone production from normal or malfunctioning corpus luteum

To examine whether luteal phase defect is, in part, causally related to insufficient gonadotrophin stimulation, we compared the relation of the increment of serum progesterone concentrations in response to human chorionic gonadotrophin (HCG) with its basal level at mid-luteal phase. Thirty-eight naturally cycling infertile women aged between 27-41 years old were evaluated for hormonal responses to HCG injection at the mid-luteal phase. We measured luteinizing hormone (LH), follicle stimulating hormone (FSH), oestradiol and progesterone concentrations, before and 1, 2 and 3 h after the administration of HCG (5000 IU, i.m.) 7 days after ovulation verified by ultrasonography. Eleven out of 38 women exhibited progesterone concentrations below 10 ng/ml (low progesterone group), and those remaining showed progesterone concentrations of > or = 10 ng/ml (normal progesterone group). The basal LH, FSH and oestradiol concentrations were essentially the same in both groups. Progesterone concentrations rose significantly 1 h after the injection and levelled off thereafter. The increment of progesterone concentrations at 1 h in the normal progesterone group was 5.7 ng/ml on the average, whereas that in low progesterone group was 1.1 ng/ml. Furthermore, the percentage increase in progesterone concentrations at 1 h in the normal progesterone group was significantly greater than that in the low progesterone group. Both groups equally exhibited significant but marginal increases in oestradiol concentrations 1 h after the injection. LH and FSH concentrations at 3 h decreased significantly in both groups. In summary, HCG readily stimulates progesterone production in normally functioning corpus luteum whereas its stimulatory effect is minimal on malfunctioning corpus luteum. This suggests that luteal phase defect is not caused by inadequate gonadotrophin stimulation and, therefore, does not benefit from HCG administration.

An immunological method for the detection of captopril-protein conjugate

To clarify the mechanism of cytotoxicity induced by captopril (Cp), interactions between tissue protein and Cp were studied by the enzyme-linked immunosorbent assay (ELISA) method. The amide-linked adducts [hemocyanin from keyhole limpet-Cp adduct (KLH-Cp) and poly-L-Lys-Cp adduct (pLys-Cp)] using carbodiimide, and a disulfide-linked adduct [ovalbumin-Cp adduct (OVA-Cp)] were prepared. To determine the formation of the protein-Cp adduct, rabbit antisera against KLH-Cp was employed. The immunoreactivities with pLys-Cp and OVA-Cp against anti KLH-Cp sera were elevated when compared with the unmodified protein. With the inhibition ELISA, this antisera was useful for detecting the Cp disulfide-linked conjugate. In kidney cytosol, a high level of immunoreactivity was observed. Plasma and liver cytosol reactivities were similar, and approximately 40% against kidney cytosol. Thus, a method for the detection of the Cp-protein adduct using ELISA has been established. Formation of the Cp-protein adduct was observed in rat plasma and in liver and kidney cytosol. These findings suggest the possibility that the formation of Cp-protein adduct is partially related to cytotoxicity in liver.

Computational observation of an ion permeation through a channel protein

The ion permeation process, driven by a membrane potential through an outer membrane protein, OmpF porin of Escherichia coli, was simulated by molecular dynamics. A Na+ ion, initially placed in the solvent region at the outer side of the porin channel, moved along the electric field passing through the porin channel in a 1.3 nsec simulation; the permeation rate was consistent with the experimentally estimated channel activity (10(8)-10(9)/sec). It this simulation, it was indicated that the ion permeation through the porin channel proceeds by a "push-out" mechanism, and that Asp113 is an important residue for the channel activity.

Effects of fatty acids on serum binding between furosemide and valproic acid

The effects of fatty acids, including oleate, on the interaction between furosemide and valproic acid in sera at respective serum therapeutic concentration levels were investigated using an ultrafiltration technique. The free fraction of furosemide was significantly increased in the presence of valproic acid. Mutual displacement experiments indicated that furosemide and valproic acid share a common high affinity binding site on human serum albumin (HSA). The serum free fraction of furosemide was increased by the presence of six or more fatty acid molecules per HSA molecule. This fatty acid-induced increase in the unbound fraction of furosemide was further increased by the binding of valproic acid. However, the inhibition of furosemide binding to serum for a fatty acid-valproic acid-furosemide system is nearly the same as the additive effect of fatty acid and valproic acid on the furosemide to serum. Thus, the mechanism for the displacement of HSA-bound furosemide by valproic acid was concluded to be different from that for fatty acid-catalyzed displacement.

Successful application of pentoxifylline in the treatment of HTLV-I associated myelopathy

Fifteen patients with human T-cell lymphotropic virus type-I (HTLV-I)-associated myelopathy (HAM) were treated in an uncontrolled preliminary trial by oral administration of pentoxifylline (PTX). Motor function, neurological evaluation, immunological markers and parameters were evaluated after four weeks. In 13 of the 15 patients, motor disability, especially spasticity, improved substantially. PTX suppressed spontaneous proliferation of peripheral blood mononuclear cells in 14 of the 15 patients at four weeks. No adverse effect was observed. We concluded that PTX may be a safe and beneficial agent for the treatment of HAM.

Interactions of aldosterone antagonist diuretics with human serum proteins

PURPOSE

The purpose of this study was to investigate the binding mechanism of aldosterone antagonist diuretics with human serum proteins, human serum albumin (HSA) and alpha 1-acid glycoprotein (AGP), as well as to identify the binding sites of the drugs on these proteins.

METHODS

Binding activities of spironolactone (SP) and its pharmacologically active metabolite canrenone (CR) to serum and serum protein were examined by ultrafiltration and spectroscopic techniques. The data for the binding of these drugs to HSA were analyzed on the basis of a theoretical model of simultaneous binding of the ligands.

RESULTS

The binding percentages of antagonist diuretics SP and CR to human serum proteins were 88.0% and 99.2%, respectively, at therapeutic concentrations. SP bound strongly only to HSA. In addition, the displacement results found using fluorescent probes and ultrafiltration methods demonstrated that SP bound to site I, particularly to the warfarin region on HSA, and to the basic binding site on AGP, while CR bound to the warfarin region on HSA.

CONCLUSIONS

The limited results presented here stress the need for caution on coadministration of acidic drugs which bind to the warfarin region on HSA and basic drugs which bind to AGP with SP and its metabolite CR.

Quantitative analysis of the spreading of the mouse trophoblast in vitro: a model for early invasion

The outgrowth of the mouse blastocyst in culture represents an in vitro model of trophoblastic invasion. In the present study we analysed trophoblast spreading by time lapse video microscopy. Trophoblast spreading consists of (1) the migration and (2) the giant cell transformation of trophoblast cells, (3) the proliferation of ectoplacental cone (EPC) cells and (4) the subsequent transformation of EPC cells into the secondary giant cells. During migration, ruffling of the trophoblast cell membrane is followed by the formation of lamellipodia. The mean surface areas of the spreading trophoblast, measured in more than 100 cultured blastocysts, increased linearly from 48 to 96 h of culture, while the linear migratory speed at the periphery of the outgrowth declined as the time of culture advanced. The EPC cells increased in size approximately eightfold during the giant cell transformation. The apparent nuclear:cytoplasmic ratios, i.e., ratios between the size of nucleus and that of the cytoplasm, measured as the surface areas on the photomicrographs, of EPC cells increased between 40-46 h of culture, but a sharp decline in the ratio occurred between 50 and 51 h of culture, reflecting either the sudden and tremendous increase in the cellular volume and/or spreading of the cytoplasm. The rates of trophoblast spreading varied considerably among the blastocysts of different genetic constitution examined (ICR, C57BL/6, C3H/He and (B6 x C3)F1. It was fastest in blastocysts obtained from matings of males and females of (B6 x C3)F1, and slowest in the C57BL/6 embryos. The differences in the rate of outgrowth observed may not simply be ascribed to difference in the developmental speed of the early embryos, because the rate of outgrowth reached a plateau at about 96-120 h and no "catch-up' was observed by leaving the blastocysts in culture longer. Our results strongly suggest the possible presence of genetic regulatory mechanisms underlying trophoblast outgrowth; further analysis of the phenomenon may provide clues to understand the molecular mechanisms of trophoblastic invasion during the early phase of implantation, hopefully leading to improved success rates of in vitro fertilization-embryo transfer.

Mode of interaction of loop diuretics with human serum albumin and characterization of binding site

PURPOSE

The purpose of this study was to investigate the binding mechanism of loop diuretics with HSA and to characterize the binding site on HSA.

METHODS

Quantitative analysis of potential interaction between ligands bound to HSA was performed by equilibrium dialysis and data for binding of the two ligands to HSA were analyzed on the basis of a theoretical model of simultaneous binding of two ligands.

RESULTS

The binding of loop diuretics is dependent upon the N-B transition, conformational change of albumin. Furthermore, from the results of binding of the drugs to modified HSA, the lysine residue seems to be involved in the binding of loop diuretics to HSA.

CONCLUSIONS

Analysis using models describing independent, competitive, cooperative and anti-cooperative binding led to the conclusion that loop diuretics bind to site I, particularly to the warfarin region on HSA.

Characterization of a nonsense mutation in the ceruloplasmin gene resulting in diabetes and neurodegenerative disease

We report here on the characterization of a mutation in the ceruloplasmin gene in a 45 year old woman with insulin-dependent diabetes mellitus who presented with the recent onset of gait disturbance and dysarthria. Physical examination revealed an ataxic gait, scanning speech and retinal degeneration. Magnetic resonance imaging of the brain was consistent with increased basal ganglia iron content and laboratory studies revealed a low serum iron concentration and no detectable serum ceruloplasmin. Nucleotide sequence analysis of the ceruloplasmin gene from this patient revealed a G to A substitution in exon 15 resulting in a nonsense mutation at amino acid 858 (Trp858ter). The patient's younger, neurologically asymptomatic brother was also found to be homozygous for this mutation. Taken together the clinical and genetic data support the concept of an essential and unique role for ceruloplasmin in human iron metabolism. Identification of this kindred extends the spectrum of ceruloplasmin gene mutations resulting in this autosomal recessive, late-onset neurodegenerative disease and highlights the importance of recognizing aceruloplasminemia as a genetic cause of diabetes and neurologic disease.

'Split tolerance' induction by intrathymic injection of acetylcholine receptor in a rat model of autoimmune myasthenia gravis; implications for the design of specific immunotherapies

Experimental autoimmune myasthenia gravis (EAMG) in the Lewis rat, induced by a single injection of acetylcholine receptor (AChR) protein, is a model used to study human myasthenia gravis (MG). The production of anti-AChR antibodies in the animal model and human MG is T cell-dependent, and AChR-specific T cells have been considered as a potential target for specific immunotherapy. Intrathymic injection of antigens induces antigen-specific tolerance in several T cell-mediated autoimmune models. We examined the effect of intrathymic injection of AChR on T cell responses and the production of antibodies to AChR in EAMG rats. Primed lymph node cells from rats receiving intrathymic injection of AChR exhibited reduced proliferation to AChR with marked suppression of interferon-gamma (IFN-gamma) secretion in the antigen-stimulated culture, compared with those of rats injected with PBS. However, neither anti-Narke AChR nor anti-rat AChR antibody production was suppressed or enhanced in intrathymically AChR-injected animals compared with that of animals injected intrathymically with PBS or perithymically with AChR. This 'split tolerance' may be attributable to the suppression of type-1 T helper cells (Th1). Our results suggest that the suppression of Th1 function alone may not be sufficient for the prevention of antibody-mediated autoimmune diseases.

Seronegative myasthenia gravis associated with atonic urinary bladder and accommodative insufficiency

We report a 20-year-old female with generalized myasthenia gravis (MG) who developed atonic urinary bladder and accommodative insufficiency. Although her sera did not contain antibodies to either nicotinic acetylcholine receptor (AChR) or voltage-gated calcium channels, a positive intravenous edrophonium test and a waning phenomenon on electromyographic studies indicated a diagnosis of seronegative MG. Myasthenic symptoms as well as urinary incontinence and impaired near vision disappeared with slight sequelae after corticosteroid therapy and total removal of the hyperplastic thymus. These symptoms recurred during a tapering course of corticosteroids, and improved again with an increased dose. Therefore, in this patient, the neuromuscular transmission of muscarinic type of AChR in the smooth muscles was also affected. This patient provides insight into the mechanisms by which some smooth muscles are involved in MG.

Antibodies to recombinant synaptotagmin and calcium channel subtypes in Lambert-Eaton myasthenic syndrome

Several proteins have been postulated as possible targets of immune attack in Lambert-Eaton myasthenic syndrome (LEMS). Heterogeneity of autoantibodies in sera from 20 LEMS patients was studied by comparing their reactivity to synaptotagmin, a synaptic vesicle protein, and voltage-gated calcium channels (VGCCs). Six patients' sera (1 with small cell lung carcinoma (SCLC)) contained antibodies specifically recognizing the recombinant synaptotagmin on immunoblots. Thirteen (11 with SCLC) and 16 (11 with SCLC and 1 with poorly differentiated cell carcinoma in the lung) patients' sera immunoprecipitated omega-conotoxin GVIA-labeled N-type and omega-conotoxin MVIIC-labeled Q-type VGCCs, respectively. Three of 6 synaptotagmin-positive sera had cross-reactivity with N and/or Q subtypes of VGCC; the remaining 3 showed no cross-reactivity with VGCCs. Results indicate that LEMS sera are heterogeneous in the spectrum of containing antibodies, and suggest that this heterogeneity reflects the immune response to various synaptic proteins including not only multiple VGCCs but also synaptosecretory complex proteins.

[Effects of polychlorinated biphenyls on regeneration of the peripheral nerve in rats]

The effects of polychlorinated biphenyls (PCB) on regeneration of the peripheral nerves were investigated in rats. The sciatic nerves were crushed at the mid-thigh level on the last day of 32 days of oral administration of PCB. The sciatic nerves were biopsied from the crushed regions at 1, 2, 4, 8 and 12 weeks after crushing. Myelin thickness on the axon diameter was smaller in the PCB administered group than in the control group. There was no difference between the experimental group and the control group in the density of regenerating fibers and distribution of fiber diameters in unmyelinated fibers. After 12 weeks the number of large diameter myelinated fiber densities was lower in the experimental group than in the control group. These results indicate that PCB may affect the remyelination of the regenerating nerve.

[Anti-voltage-gated calcium channel antibodies in the Lambert-Eaton myasthenic syndrome]

We have tested 29 patients with the Lambert-Eaton myasthenic syndrome (LEMS) for serum antibodies to voltage-gated calcium channels (VGCC) using an immunoprecipitation assay in which [125]-omega-conotoxin GVIA is used to label calcium channels extracted from IMR-32, a human neuroblastoma cell line. Fifty-five percent of these patients had significant levels of antibody [31.6 (26.5, 48.2) (med., Q1, Q3) pmol/L, n = 29], compared with healthy controls [21.5 +/- 3.4 (mean +/- SD) pmol/L, n = 30] and other neurological disorders [25.2 +/- 4.2 (mean +/- SD) pmol/L, n = 10]. These antibodies were found in 43% of the patients with small cell lung carcinoma (SCLC) without signs and symptoms of LEMS [32.2 +/- 7.2 (mean +/- SD) pmol/L n = 30] and 7% of the myasthenic patients [21.4 +/- 6.8 (mean +/- SD) pmol/L n = 14]. Anti-VGCC antibody titers did not correlate with presence of SCLC, disease duration, or an electromyographic index of disease severity. Our results suggest that the antibodies detected in this assay are specific to some patients with LEMS, but not all. This assay is a useful aid in diagnosing LEMS but has much room for improvement.

Membrane fluidity changes of liposomes in response to various odorants. Complexity of membrane composition and variety of adsorption sites for odorants

Three kinds of liposomes prepared from phosphatidylcholine (PC), azolectin, and azolectin-containing membrane proteins of the canine erythrocytes were used as models for olfactory cells. To explore properties of the adsorption sites of odorants, membrane fluidity changes in response to various odorants were measured with various fluorescence dyes which monitor the fluidity at different depths and different regions of the membranes. (a) Application of various odorants changed the membrane fluidity of azolectin liposomes. The patterns of membrane fluidity changes in response to odorants having a similar odor were similar to each other and those in response to odorants having different odors were different from each other. These results suggested that odorants having a similar odor are adsorbed on a similar site and odorants having different odors are adsorbed on different sites. (b) Such variation of the pattern was not seen in liposomes of a simple composition (PC liposome). (c) In the proteoliposomes whose composition was more complex than that of azolectin liposomes, the patterns of membrane fluidity changes varied among odorants having a similar odor. It was concluded that liposomes of complex membrane composition have the variety of adsorption sites for odorants.

[Differential effect of sodium bicarbonate on disposition of sulfadimethoxine and sulfisoxazole in rabbits]

The orally co-administered sodium bicarbonate significantly enhanced the blood concentration of sulfadimethoxine at the early stage after oral administration to rabbits, by increasing its intestinal absorption. On the other hand, the sodium bicarbonate significantly reduced the blood concentration of sulfisoxazole at the elimination phase after oral administration to rabbits, by increasing its urinary excretion. The fact that sodium bicarbonate exhibits different effects in the disposition of these two sulfonamides is an interesting example to gain a better understanding for the complexity of drug interaction.

Drug binding to alpha 1-acid glycoprotein studied by circular dichroism

The interactions of acidic and basic drugs with alpha 1-acid glycoprotein (alpha 1-AGP) were investigated using circular dichroism (CD) measurements. Extrinsic Cotton effects were generated by the binding of drugs to alpha 1-AGP. The CD data suggested the presence of a single binding site on the alpha 1-AGP molecule. The induced ellipticities of the acidic drug-alpha 1-AGP system decreased with increasing pH, while the ellipticities for the basic drugs increased with pH. The ellipticities for all drugs were reduced by the addition of fatty acids. Furthermore, the induced ellipticities decreased in the presence of cesium chloride for basic drugs bound to alpha 1-AGP. The extrinsic Cotton effects therefore appear to result from hydrophobic interaction with alpha 1-AGP for the acidic drugs and from hydrophobic and electrostatic interactions for the basic drugs.

A comparative study of the interaction of warfarin with human alpha 1-acid glycoprotein and human albumin

The interaction of warfarin with human alpha 1-acid glycoprotein (alpha 1-AGP) and human albumin (HA) has been investigated using fluorescence and circular dichroism techniques. The fluorescence of warfarin is greatly enhanced following binding to alpha 1-AGP or HA, the binding constant for a single site being estimated by the Scatchard method. The binding constants for the two serum proteins are similar, but the thermodynamic parameters differ. The binding constants increase as the pH is raised to 9.0. Various basic drugs, such as chlorpromazine, propranolol and imipramine, markedly inhibited the binding of warfarin to alpha 1-AGP. But, some acidic drugs, including phenylbutazone, effectively displaced warfarin bound to HA. The difference in CD spectra observed for alpha 1-AGP and HA indicated that the drug-binding sites of the two proteins might have different asymmetries. It thus appears that the mode of interaction of warfarin with the two proteins differs.