Incidence and associated factors of neutralizing anti-interferon antibodies among chronic hepatitis C patients treated with interferon in Taiwan

BACKGROUND

The administration of interferon (IFN) could be complicated by the development of neutralizing anti-interferon antibodies (NA). This study evaluates the frequency and associated factors of NA among chronic hepatitis C patients treated with different IFNs.

METHODS

Ninety-five chronic hepatitis C patients were randomized to be treated with recombinant IFN-alpha2a (n = 28), IFN-alpha2b (n = 39) or lymphoblastoid IFN-alpha1 (n = 28) given intramuscularly, 3-6 million units, thrice weekly for 24 weeks. Serum samples collected before, during and after the cessation of treatment were checked for NA.

RESULTS

Three patients were withdrawn from treatment. All patients were negative for NA before treatment and 13 (14%) patients developed neutralizing antibodies. Of the 26 patients treated with IFN-alpha2a, 6 (23.1%) developed NA. whereas NA were detected in only 6 (15.4%) of 39 and 1 (3.7%) of 27 patients treated with IFN-alpha2b and IFN-alphanl, respectively. Age, gender, HCV genotype, ALT level, IFN total dose and liver histology were not associated with the development of NA. By using multivariate logistic regression it was shown that pretreatment HCV RNA level and IFN preparation were the two major factors related to the production of NA. The response of treatment was related to pretreatment viremia but not to the presence of NA.

CONCLUSIONS

The frequency of development of NA among Taiwanese patients with chronic hepatitis C might be related to different IFN preparations and pretreatment HCV RNA level. The response of treatment was related to pretreatment HCV RNA level but not to the presence of NA.

The epidemiology of TT virus (TTV) infection in a hepatitis C and B virus hyperendemic area of southern Taiwan

TT virus (TTV) is a newly isolated DNA virus from the serum of a patient with posttransfusion hepatitis of unknown etiology in 1997. To evaluate the clinical and molecular characteristics of TT virus (TTV) in a hepatitis C virus (HCV) and B (HBV) hyperendemic area (Masago), 200 residents were enrolled in the study. The sera were tested for alanine aminotransferase (ALT), HCV RNA and GB virus C/Hepatitis G virus (HGV) RNA, TTV DNA, HBsAg, anti-HCV and antibodies to HGV E2-protein (anti-E2). TTV DNA was positive in 99 of the 200 sera with a prevalence rate of 49.5%. The prevalence of HBsAg, anti-HCV, HCV RNA, HGV RNA, anti-E2 and HGV exposure (defined as positive for serum HGV RNA and/or anti-E2) was 38.9%, 69.5%, 64.5%, 17.0%, 25.5% and 39.5%, respectively. Neither clinical nor virological factors were associated with TTV viremia. The rate of ALT abnormality was significantly elevated in HCV RNA-positive (34.9%) than -negative (7.0%) residents (p < 0.001). HCV viremia was the only factor significantly associated with ALT elevation by multiple logistic regression (odds ratio: 6.96; 95% C.I.: 2.60-18.7). We concluded that in this HCV/HBV hyperendemic area, the prevalence of TTV DNA was high. No significant clinical factor was observed to be associated with TTV infection. TTV infection is not related to abnormal ALT levels and ALT abnormality was mainly attributable to HCV but not TTV, HBV or HGV infection.

[Computerized surgical simulation with 3D reconstruction of upper limbs]

This paper reports our study on how to realize computerized surgical simulation through reconstructing 3D anatomy of upper limbs. CT images and serial sections of upper limbs were matched to reconstruct 3D images. We compiled the computer programs of 3D reconstruction and surgical simulation with borland C++ computer language, and built 3D digital model of anatomic structure of upper limbs. The results showed that all structures reconstructed could be displayed alone, in any group or totally. While operating, we could choose one of three segments of the upper limbs model and operate on any parts and in any direction. The surgical simulation system could be used to design operative schemes, choose the best operative paths, and teach the processes of operations and anatomy. It could run in 586-personal computers.

The presence of an aqueous cavity in the proton-pumping pathway of the pyridine nucleotide transhydrogenase of Escherichia coli is suggested by the reaction of the enzyme with sulfhydryl inhibitors

The pyridine nucleotide transhydrogenase of Escherichia coli carries out transmembrane proton translocation coupled to transfer of a hydride ion equivalent between NAD(+) and NADP(+). The membrane domain (domain II) of the enzyme is composed of 13 transmembrane helices. Previous studies (N. A. Glavas et al., Biochemistry 34, 7694-7702, 1995) have suggested that betaHis91 in transmembrane helix 9 is involved in the translocation pathway of protons across the membrane. In this study we have replaced amino acid residues on the same face of helix 9 as betaHis91 by single cysteine residues. We then examined the effect of the sulfhydryl inhibitors N-ethylmaleimide (NEM) and p-chloromercuriphenylsulfonate (pCMPS) on enzyme activity and, in the case of [(14)C]NEM, as an enzyme label. The pattern of enzyme inhibition and labelling is consistent with the presence of an aqueous cavity through domain II from the cytosolic surface to the region of betaHis91. Residue betaAsn222 in helix 13, which appears also to be involved in the proton pathway across domain II, may interface with this aqueous cavity. A further series of mutants of betaGlu124 on helix 10 confirms the proposal (P. D. Bragg and C. Hou, Arch. Biochem. Biophys. 363, 182-190, 1999) that this residue is involved in passive permeation of protons across domain II.

[Effect of flooding stress on transpiration of poplar I-69/55]

The rates of transpiration(Tr) and photosynthesis(Pn) of poplar I-69/55 trees were measured under flooding stress. Flooding stress caused Pn and Tr decreasing, while in the period of measurement, Pn almost didn't change. The longer the period of flooding stress was, the more the Tr and stomatal conductance (Gs) decreased. Undre no stress, Pn and Tr of test trees displayed daily double-peak curves and seasonal variations, with the maximum in summer. Water use efficiency also displayed seasonal variation, with the maximum in autumn. Under no stress, Tr obviously changed with tree ages, with the order of 1 year-old > 3 year-old > 7 year-old. The rate of Tr/Pn in spring, summer and autumn was higher than that of other deciduous broad-leaved trees in the same region, especially in summer. The high Tr/Pn ratio means a high water consumption, which is beneficial to water loss of poplar I-69/55. In shoal sites, the temperature of leaf surface in summer and autumn is the most important factor that affects the transpiration rate of poplar I-69/55, suggesting that decreasing the temperature of leaf suface is beneficial to increase the transpiration rate. During the two days after flooding, the temperature of leaf surface is still the important factor that affects transpiration rate.

Crosslinking between alpha and beta subunits defines the orientation and spatial relationship of some of the transmembrane helices of the proton-translocating pyridine nucleotide transhydrogenase of Escherichia coli

The proton-translocating pyridine nucleotide transhydrogenase of Escherichia coli is composed of two types of subunits, alpha and beta, organized as an alpha(2)beta(2) tetramer. The protein contains three recognizable domains, of which domain II is the transmembrane region of the molecule containing the pathway for proton translocation. Domain II is composed of four transmembrane helices at the carboxyl-terminus of the alpha subunit and either eight or nine transmembrane helices at the amino-terminal region of the beta subunit. We have introduced pairs of cysteine residues into a cysteine-free transhydrogenase by site-directed mutagenesis. Disulfide bond formation between some of these cysteine residues occurred spontaneously or on treatment with cupric 1, 10-phenanthrolinate. Analysis of crosslinked products confirmed that there are nine transmembrane helices in the domain II region of the beta subunit. The proximity to one another of several of the transmembrane helices was determined. Thus, helices 2 and 4 are close to helix 6 (nomenclature of Meuller and Rydström, J. Biol. Chem. 274, 19072-19080, 1999), and helix 3 and the carboxyl-terminal eight residues of the alpha subunit are close to helix 7. In the alpha(2)beta(2) tetramer, helices 2 and 4 of one alpha subunit are close to the same pair of transmembrane helices of the other alpha subunit, and helix 6 of one beta subunit is close to helix 6 of the other beta subunit.

[The detection of disparity evoked potentials in anisometropes]

OBJECTIVE

To investigate the affection of anisometropia on stereopsis and its mechanism.

METHODS

A new set of static random-dot stereograms was utilized as a stimulus to elicit evoked potentials in 20 anisometropes and 40 normal subjects.

RESULTS

Under the stimulus of different degrees of disparity in anisometropes, the P(250) waves related to stereopsis could be recorded. However, the percentage of their P(250) wave amplitude over the plane figure was significantly lower than that of normal persons (P < 0.05). The P(250) wave mean amplitude of severe anisometropes (aniseikonia >or= 5%) in fine disparity (14' and 23') was lower than that in mild anisometropes (aniseikonia < 5%, P < 0.05).

CONCLUSIONS

Anisometropia may affect and disturb the stereopsis. The degree of disturbance is related to the degree of anisometropia. The higher the degree of anisometropia, the lower the amplitude of the P(250) potential, and the main defect is at the part of fine disparity.

Monitoring Inositol-Specific Phospholipase C Activity Using a Phospholipid FlashPlate(R)

Inositol-specific phospholipase Cs(PLCs) are a group of enzymes involved in the signal transduction pathway of many plasma membrane receptor mediated events. We developed a modified solid surface to capture [(3)H] PIP(2) onto the Basic FlashPlate(R) in order to monitor PLC activity. Our results clearly demonstrate the utility of [(3)H] PIP(2)-Coated Phospholipid FlashPlate(R) microtiter plates for assessing PLC activity for HTS of receptor-coupled functional assays. The results show that PLC activity can be measured easily from a variety of sources including purified recombinant enzyme preparations, crude HL60 cell lysates and permeabilized A431 human carcinoma cells. Moreover, this format provides a surface comparable to that used for classical solution based radiolabeled mixed phospholipid micelle studies and illustrates the feasibility of this assay for measuring PLC activation in a variety of different drug screening assays.

2-((2-((dimethylamino)methyl)phenyl)thio)-5-iodophenylamine (ADAM): an improved serotonin transporter ligand

Serotonin transporters (SERT) are target-sites for commonly used antidepressants, such as fluoxetine, paroxetine, sertraline, and so on. Imaging of these sites in the living human brain may provide an important tool to evaluate the mechanisms of action as well as to monitor the treatment of depressed patients. Synthesis and characterization of an improved SERT imaging agent, ADAM (2-((2-((dimethylamino)methyl)phenyl)thio)-5-iodophenylamine)(7) was achieved. The new compound, ADAM(7), displayed an extremely potent binding affinity toward SERT ( K(i)=0.013 nM, in membrane preparations of LLC-PK(1)-cloned cell lines expressing the specific monoamine transporter). ADAM(7) also showed more than 1,000-fold selectivity for SERT over norepinephrine transporter (NET) and dopamine transporter (DAT) ( K(i)=699 and 840 nM, for NET and DAT, respectively). The radiolabeled compound [(125)I]ADAM(7) showed an excellent brain uptake in rats (1.41% dose at 2 min post intravenous [IV] injection), and consistently displayed the highest uptake (between 60-240 min post IV injection) in hypothalamus, a region with the highest density of SERT. The specific uptake of [(125)I]ADAM(7) in the hypothalamus exhibited the highest target-to-nontarget ratio ([hypothalamus - cerebellum]/cerebellum was 3.97 at 120 min post IV injection). The preliminary imaging study of [(123)I]ADAM in the brain of a baboon by single photon emission computed tomography (SPECT) at 180-240 min post IV injection indicated a specific uptake in midbrain region rich in SERT. These data suggest that the new ligand [(123)I]ADAM(7) may be useful for SPECT imaging of SERT binding sites in the human brain.

[Clinical study on chitosan for prevention of elbow adhesion]

OBJECTIVE

To study the clinical effect of chitosan on prevention of elbow adhesion after elbow arthrolysis.

METHODS

Twenty six patients with elbow ankylosis were performed elbow arthrolysis, which divided into two groups, in chitosan group, 12 patients were injected 2% chitosan into the elbow joint cavity, and no chitosan used in the other 14 patients as control group. The average range of extension and flexion of elbow joint was detected to evaluate the clinical results.

RESULTS

All patients were followed up 8 to 51 months, averaged 24 months. In the chitosan group, the average range of extension and flexion of elbow joint was restored to 92.9 degrees +/- 20.9 degrees, with an average increase of 55.0 degrees +/- 15.9 degrees compared with preoperation. In the control group, the average range of extension and flexion of elbow joint was restored to 75.4 degrees +/- 17.5 degrees, with an average increase of 38.2 degrees +/- 11.9 degrees. The outcome showed significant difference between the chitosan group and the control group (P < 0.01).

CONCLUSION

Chitosan can prevent or reduce elbow adhesion after elbow arthrolysis.

A novel serotonin transporter ligand: (5-iodo-2-(2-dimethylaminomethylphenoxy)-benzyl alcohol

The serotonin transporters (SERT) are the primary binding sites for selective serotonin reuptake inhibitors, commonly used antidepressants such as fluoxetine, sertraline, and paroxetine. Imaging of SERT with positron emission tomography and single photon emission computed tomography in humans would provide a useful tool for understanding how alterations of this system are related to depressive illnesses and other psychiatric disorders. In this article the synthesis and characterization of [(125)I]ODAM [(5-iodo-2-(2-dimethylaminomethylphenoxy)-benzyl alcohol, 9)] as an imaging agent in the evaluation of central nervous system SERT are reported. A new reaction scheme was developed for the preparation of compound 9, ODAM, and the corresponding tri-n-butyltin derivative 10. Upon reacting 10 with hydrogen peroxide and sodium[(125)I]iodide, the radiolabeled [(125)95%). In an initial binding study using cortical membrane homogenates of rat brain, ODAM displayed a good binding affinity with a value of K(i) = 2.8 +/- 0.88 nM. Using LLC-PK(1) cells specifically expressing the individual transporter (i.e. dopamine [DAT], norepinephrine [NET], and SERT, respectively), ODAM showed a strong inhibition on SERT (K(i) = 0.12 +/- 0.02 nM). Inhibition constants for the other two transporters were lower (K(i) = 3.9 +/- 0.7 microM and 20.0 +/- 1.9 nM for DAT and NET, respectively). Initial biodistribution study in rats after an intravenous (IV) injection of [(125)I]ODAM showed a rapid brain uptake and washout (2.03, 1.49, 0.79, 0.27, and 0.07% dose/organ at 2, 30, 60, 120, and 240 min, respectively). The hypothalamus region where the serotonin neurons are located exhibited a high specific uptake. Ratios of hypothalamus-cerebellum/cerebellum based on percent dose per gram of these two regions showed values of 0.35, 0. 86, 0.86, 0.63, and 0.34 at 2, 30, 60, 120, and 240 min, post-IV injection, respectively. The specific uptake in hypothalamus can be effectively blocked by pretreatment of known SERT ligands. The results suggest that this novel ligand displays desirable in vitro and in vivo properties as a potential SERT imaging agent.

[Experimental and clinical study of gentamicin-loaded chitosan drug delivery system]

OBJECTIVE

To conduct a clinical study and release test for a drug delivery system (DDS) of gentamicin-loaded chitosan bar in attempt to extend its clinical application.

METHODS

The diffusion behavior of gentamicin from chitosan DDS was detected using in vitro, in vivo release test. Eighteen cases of chronic osteomyelitis were treated by chitosan DDS. The clinical result was evaluated by wound healing and clinical and X-radiographic manifestation.

RESULTS

Concentration of gentamicin about 926.7 microg/bar/day was released from DDS within the first 24 hours by in vitro diffusion test. It fell and sustained by 25th day with rate of 4.0 microg x bar(-1) x day(-1). In in vivo study, serum gentamicin concentration reached its peak level (0.92 microg/ml) 24 hours after implantation. No increase was observed in the concentration of BUN and Cr. In all bone tissue around the bar, 8 weeks after oderation the gentamicin concentration exceeded the minimum inhibitory concentration for the common causative organisms of osteomyelitis. The follow up time was 24.8 months (6 - 34). The initial cure ratio was 2/18 and the recurrence ratio zero.

CONCLUSION

The gentamicin-loaded chitosan bar is a good DDS with sustained antibiotic effect in vivo and in vitro. It is an effective method for the treatment of bone infection.

Autistic savants. [correction of artistic]

OBJECTIVE

The objectives of this study were to examine common patterns in the lives and artwork of five artistic savants previously described and to report on the clinical, neuropsychological, and neuroimaging findings from one newly diagnosed artistic savant.

BACKGROUND

The artistic savant syndrome has been recognized for centuries, although its neuroanatomic basis remains a mystery.

METHODS

The cardinal features, strengths, and weaknesses of the work of these six savants were analyzed and compared with those of children with autism in whom artistic talent was absent. An anatomic substrate for these behaviors was considered in the context of newly emerging theories related to paradoxical functional facilitation, visual thinking, and multiple intelligences.

RESULTS

The artists had features of "pervasive developmental disorder," including impairment in social interaction and communication as well as restricted repetitive and stereotyped patterns of behavior, interest, and activities. All six demonstrated a strong preference for a single art medium and showed a restricted variation in artistic themes. None understood art theory. Some autistic features contributed to their success, including attention to visual detail, a tendency toward ritualistic compulsive repetition, the ability to focus on one topic at the expense of other interests, and intact memory and visuospatial skills.

CONCLUSIONS

The artistic savant syndrome remains rare and mysterious in origin. Savants exhibit extraordinary visual talents along with profound linguistic and social impairment. The intense focus on and ability to remember visual detail contributes to the artistic product of the savant. The anatomic substrate for the savant syndrome may involve loss of function in the left temporal lobe with enhanced function of the posterior neocortex.

Effect of NBD chloride (4-chloro-7-nitrobenzo-2-oxa-1,3-diazole) on the pyridine nucleotide transhydrogenase of Escherichia coli

Pyridine nucleotide transhydrogenases of bacterial cytosolic membranes and mitochondrial inner membranes are proton pumps in which hydride transfer between NADP(+) and NAD(+) is coupled to proton translocation across cytosolic or mitochondrial membranes. The pyridine nucleotide transhydrogenase of Escherichia coli is composed of two subunits (alpha and beta). Three domains are recognized. The extrinsic cytosolic domain 1 of the amino-terminal region of the alpha subunit bears the NAD(H)-binding site. The NADP(H)-binding site is present in domain 3, the extrinsic cytosolic carboxyl-terminal region of the beta subunit. Domain 2 is composed of the membrane-intrinsic carboxyl-terminal region of the alpha subunit and the membrane-intrinsic amino-terminal region of the beta subunit. Treatment of the transhydrogenase of E. coli with 4-chloro-7-nitrobenzo-2-oxa-1,3-diazole (NBD chloride) inhibited enzyme activity. Analysis of inhibition revealed that several sites on the enzyme were involved. NBD chloride modified two (betaCys-147 and betaCys-260) of the seven cysteine residues present in the transhydrogenase. Modification of betaCys-260 in domain 2 resulted in inhibition of enzyme activity. Modification of residues other than cysteine residues also resulted in inhibition of transhydrogenation as shown by use of a cysteine-free mutant enzyme. The beta subunit was modified by NBD chloride to a greater extent than the alpha subunit. Reaction of domain 2 and domain 3 was prevented by NADPH. Modification of domain 3 is probably not associated with inhibition of enzyme activity. Modification of domain 2 of the beta subunit resulted in a decreased binding affinity for NADPH at its binding site in domain 3. The product resulting from the reaction of NBD chloride with NADPH was a very effective inhibitor of transhydrogenation. In experiments with NBD chloride in the presence of NADPH it is likely that all of the sites of reaction described above will contribute to the inhibition observed. The NBD-NADPH adduct will likely be more useful than NBD chloride in investigations of the pyridine nucleotide transhydrogenase.

Single-photon emission tomography imaging of serotonin transporters in the nonhuman primate brain with [(123)I]ODAM

We have described previously a selective serotonin transporter (SERT) radioligand, [(123)I]IDAM. We now report a similarly potent, but more stable IDAM derivative, 5-iodo-2-[2-[(dimethylamino)methyl]phenoxy]benzyl alcohol ([(123)I]ODAM). The imaging characteristics of this radioligand were studied and compared against [(123)I]IDAM. Dynamic sequences of single-photon emission tomography (SPET) scans were obtained on three female baboons after injection of 375 MBq of [(123)I]ODAM. Displacing doses (1 mg/kg) of the selective SERT ligand (+)McN5652 were administered 120 min after injection of [(123)I]ODAM. Total integrated brain uptake of [(123)I]ODAM was about 30% higher than [(123)I]IDAM. After 60-120 min, the regional distribution of tracer within the brain reflected the characteristic distribution of SERT. Peak specific binding in the midbrain occurred 120 min after injection, with an equilibrium midbrain to cerebellar ratio of 1. 50+/-0.08, which was slightly lower than the value for [(123)I]IDAM (1.80+/- 0.13). Both the binding kinetics and the metabolism of [(123)I]ODAM were slower than those of [(123)I]IDAM. Following injection of a competing SERT ligand, (+)McN5652, the tracer exhibited washout from areas with high concentrations of SERT, with a dissociation kinetic rate constant k(off)=0.0085+/-0.0028 min(-1) in the midbrain. Similar studies using nisoxetine and methylphenidate showed no displacement, consistent with its low binding affinity to norepinephrine and dopamine transporters, respectively. These results suggest that [(123)I]ODAM is suitable for selective SPET imaging of SERT in the primate brain, with higher uptake and slower kinetics and metabolism than [(123)I]IDAM, but also a slightly lower selectivity for SERT.

Characterization of [(123)I]IDAM as a novel single-photon emission tomography tracer for serotonin transporters

Development of selective serotonin transporter (SERT) tracers for single-photon emission tomography (SPET) is important for studying the underlying pharmacology and interaction of specific serotonin reuptake site inhibitors, commonly used antidepressants, at the SERT sites in the human brain. In search of a new tracer for imaging SERT, IDAM (5-iodo-2-[[2-2-[(dimethylamino)methyl]phenyl]thio]benzyl alcohol) was developed. In vitro characterization of IDAM was carried out with binding studies in cell lines and rat tissue homogenates. In vivo binding of [(125)I]IDAM was evaluated in rats by comparing the uptakes in different brain regions through tissue dissections and ex vivo autoradiography. In vitro binding study showed that IDAM displayed an excellent affinity to SERT sites (K(i)=0.097 nM, using membrane preparations of LLC-PK(1) cells expressing the specific transporter) and showed more than 1000-fold of selectivity for SERT over norepinehrine and dopamine (expressed in the same LLC-PK(1) cells). Scatchard analysis of [(125)I]IDAM binding to frontal cortical membrane homogenates prepared from control or p-chloroamphetamine (PCA)-treated rats was evaluated. As expected, the control membranes showed a K(d) value of 0.25 nM+/-0.05 nM and a B(max) value of 272+/-30 fmol/ mg protein, while the PCA-lesioned membranes displayed a similar K(d), but with a reduced B(max) (20+/-7 fmol/ mg protein). Biodistribution of [(125)I]IDAM (partition coefficient =473; 1-octanol/buffer) in the rat brain showed a high initial uptake (2.44%dose at 2 min after i.v. injection) with the specific binding peaked at 60 min postinjection (hypothalamus-cerebellum/cerebellum =1.75). Ex vivo autoradiographs of rat brain sections (60 min after i.v. injection of [(125)I]IDAM) showed intense labeling in several regions (olfactory tubercle, lateral septal nucleus, hypothalamic and thalamic nuclei, globus pallidus, central gray, superior colliculus, substantia nigra, interpeduncular nucleus, dorsal and median raphes and locus coeruleus), which parallel known SERT density. This novel tracer has excellent characteristics for in vivo SPET imaging of SERT in the brain.

Single-photon emission tomography imaging of serotonin transporters in the non-human primate brain with the selective radioligand [(123)I]IDAM

A new radioligand, 5-iodo-2-[[2-2-[(dimethylamino)methyl]phenyl]thio]benzyl alcohol ([(123)I]IDAM), has been developed for selective single-photon emission tomography (SPET) imaging of SERT. In vitro binding studies suggest a high selectivity of IDAM for SERT (K(i)=0.097 nM), with considerably lower affinities for norepinephrine and dopamine transporters (NET K(i)= 234 nM and DAT K(i)>10 microM, respectively). In this study the biodistribution of SERT in the baboon brain was investigated in vivo using [(123)I]IDAM and SPET imaging. Dynamic sequences of SPET scans were performed on three female baboons (Papio anubis) after injection of 555 MBq of [(123)I]IDAM. Displacing doses (1 mg/kg) of the selective SERT ligand (+)McN5652 were administered 90-120 min after injection of [(123)I]IDAM. Similar studies were performed using a NET inhibitor, nisoxetine, and a DAT blocker, methylphenidate. After 60-120 min, the regional distribution of tracer within the brain reflected the characteristic distribution of SERT, with the highest uptake in the midbrain area (hypothalamus, raphe nucleus, substantia nigra), and the lowest uptake in the cerebellum (an area presumed free of SERT). Peak specific binding in the midbrain occurred at 120 min, with a ratio to the cerebellum of 1.80+/-0.13. At 30 min, 85% of the radioactivity in the blood was metabolite. Following injection of a competing SERT ligand, (+)McN5652, the tracer exhibited rapid washout from areas with high concentrations of SERT (dissociation rate constant in the midbrain, averaged over three baboons, k(off)=0. 025+/-0.002 min(-1)), while the cerebellar activity distribution was undisturbed (washout rate 0.0059+/- 0.0003 min(-1)). Calculation of tracer washout rate pixel-by-pixel enabled the generation of parametric images of the dissociation rate constant. Similar studies using nisoxetine and methylphenidate had no effect on the distribution of [(123)I]IDAM in the brain. These results suggest that [(123)I]IDAM is suitable for selective SPET imaging of SERT in the primate brain, with high contrast, favorable kinetics, and negligible binding to either NET or DAT.

Comparison of necrotic characteristics and benefits between 50% acetic acid and pure ethanol in local hepatic injection: a study in rats

This study compares the characteristics of acetic acid and pure ethanol in local hepatic injection and identifies the possible benefits from acetic acid by an animal model. We injected 0.03 ml of pure ethanol and 0.01 ml of 50% acetic acid separately into different sites of the same liver. The shape and diameter of the lesions were recorded at 0 min, 5 min and 15 min, and 5 lesions were also reviewed one day later. The lesions induced by pure ethanol were irregular, whereas those induced by 50% acetic acid were round or oval. The diameter of lesions induced by 50% acetic acid was 2.62 +/- 0.58 mm initially and increased to 4.50 +/- 0.84 mm and 5.25 +/- 0.75 mm at 5 min and 15 min, (5 min compared with 0 min, p < 0.0001; 15 min compared with 5 min, p < 0.001) respectively. The diameters of lesions induced by pure ethanol did not increase. The diffusion diameter at 5 min and 15 min were 1.88 mm and 2.63 mm respectively. Furthermore, viable liver cells were occasionally found in two lesions induced by pure ethanol. Acetic acid had a more homogeneous distribution and better infiltrating ability than pure ethanol and may be superior to pure ethanol in local injection therapy of HCC. But more clinical trials in the treatment HCC should be carried out.

In vivo imaging of serotonin transporters with [99mTc]TRODAT-1 in nonhuman primates

[99mTc]TRODAT-1 was the first 99mTc-labeled imaging agent to show specific binding to dopamine transporters (DAT) in the striatum (STR) of human brain. Additionally, in vitro binding and autoradiographic experiments demonstrated that this tracer also binds to serotonin transporters (SERT) in the midbrain/hypothalamus (MB) area. In this study, [99mTc]TRODAT-1 was investigated as a potentially useful ligand to image SERT in the MB of living brain. A total of eight single-photon emission tomography (SPET) scans were performed in two baboons (Papio anubis) after intravenous (i.v.) injection of 740 MBq (20 mCi) of [99mTc]TRODAT-1 using a triple-head gamma camera equipped with ultra-high-resolution fan-beam collimators (scan time: 0-210 min). In four blocking studies, baboons were pretreated with (+)McN5652 (1 mg/kg, i.v.) or methylphenidate (1 mg/kg, i.v.) to specifically block SERT or DAT, respectively. After co-registration with magnetic resonance images of the same baboon, a region of interest analysis was performed using predefined templates to calculate specific uptake in the midbrain area and the striatum, with the cerebellum as the background region [(MB-CB)/CB, (STR-CB)/CB]. Additionally, two PET scans of the same baboons were performed after i.v. injections of 74-111 MBq (2-3 mCi) of [11C](+)McN5652 to identify the SERT sites. In [99mTc]TRODAT-1/SPET scans, the SERT sites in the MB region were clearly visualized. Semiquantitative analysis revealed a specific uptake in MB ([MB-CB]/CB) of 0.30+/-0.02, which was decreased to 0. 040+/-0.005 after pretreatment with nonradioactive (+)McN5652, a selective SERT ligand. Pretreatment with methylphenidate reduced the specific binding of [99mTc]TRODAT-1 to DAT sites [(STR-CB)/CB] from 2.45+/-0.13 to 0.32+/-0.04 without any effect on its binding to SERT sites [(MB-CB)/CB], which was confirmed by the co-registration of the [11C](+)McN5652/PET scans. This preliminary study suggests that specific binding of [99mTc]TRODAT-1 to SERT sites can be detected by in vivo SPET imaging despite the low target to background ratio. These findings provide impetus for further development of similar compounds with improved binding affinity and selectivity to SERT sites.

Simultaneous SPECT studies of pre- and postsynaptic dopamine binding sites in baboons

The central nervous system dopamine transporters (DATs) and dopamine D2/D3 receptors are implicated in a variety of neurological disorders. Both sites are also targets for drug treatment. With the successful development of [99mTc]TRODAT-1, single-isotope imaging studies using this ligand for DAT imaging can be complemented by additional use of 123I-labeled D2/D3 receptor ligand co-injected to assess both pre- and postsynaptic sites of the dopaminergic system simultaneously.

METHODS

Twelve SPECT scans of the brain were obtained in two baboons after intravenous administration of 740 MBq (20 mCi) [99mTc]-TRODAT-1 (technetium, [2-[[2-[[[3-(4-chlorophenyl)-8-methyl-8-azabicyclo[3,2,1]oct-2-yl]methyl ](2-mercaptoethyl) amino]ethyl]-amino]ethanethiolato (3-)]- oxo-[1R-(exo-exo)]) and 185 MBq (5 mCi) [123I]iodobenzamide or [123I]iodobenzofuran. SPECT data were acquired by a triple-head gamma camera equipped with ultra-high-resolution fanbeam collimators (scan duration = 210 min). Two sets of SPECT data were obtained using energy windows of 15% centered on 140 keV for 99mTc and 10% asymmetric with a lower bound at 159 keV for 123I. After coregistration with MRI, region-of-interest analysis was performed using predefined templates from coregistered MRI. In blocking studies, baboons were pretreated with N-methyl-2beta-carbomethoxy-3beta-(4-fluorophenyl)tropane (CFT, 14 mg) or raclopride (14 mg) to block DAT or D2/D3 binding site, respectively.

RESULTS

Image quality of dual-isotope studies was similar to that obtained from single-isotope studies. When one site was blocked with CFT or raclopride, the binding of the respective ligand to the other site was not affected.

CONCLUSION

This is the first example that clearly demonstrates the feasibility of simultaneous imaging of both pre- and postsynaptic sites of the dopaminergic system in baboons with dual-isotope SPECT studies. With or without corrections for cross-contamination of 123I into the 99mTc window, striatum-to-cerebellum ratios (target-to-nontarget) of dual-isotope experiments did not differ significantly from single-isotope experiments. This method may be a valuable and cost-effective tool for gaining comprehensive information about the dopaminergic system in one SPECT imaging session.

99mTc-labeled MIBG derivatives: novel 99mTc complexes as myocardial imaging agents for sympathetic neurons

Radioactive-iodine-labeled meta-iodobenzylguanidine (MIBG) is currently being used as an in vivo imaging agent to evaluate neuroendocrine tumors as well as the myocardial sympathetic nervous system in patients with myocardial infarct and cardiomyopathy. It is generally accepted that MIBG is an analogue of norepinephrine and its uptake in the heart corresponds to the distribution of norepinephrine and the density of sympathetic neurons. A series of MIBG derivatives containing suitable chelating functional groups N2S2 for the formation of [TcvO]3+N2S2 complex was successfully synthesized, and the 99mTc-labeled complexes were prepared and tested in rats. One of the compounds, [99mTc]2, tested showed significant, albeit lower, heart uptakes post iv injection in rats (0.21% dose/g at 4 h) as compared to [125I]MIBG (1.7% dose/g at 4 h). The heart uptake of the 99mTc-labeled complex appears to be specific and can be reduced by co-injection with nonradioactive MIBG or by pretreatment with desipramine, a selective norepinephrine transporter inhibitor. Further evaluation of the in vitro uptake of [99mTc]2 in cultured neuroblastoma cells displayed consistently lower, but measurable uptake (approximately 10% of that for [125I]MIBG). These preliminary results suggested that the mechanisms of heart uptake of [99mTc]2 may be related to those for [125I]MIBG uptake. If suitable 99mTc-labeled MIBG derivatives can be further developed, the prevalent availability of 99mTc in nuclear medicine clinics will allow them to be readily available for widespread application.

Mutation of conserved polar residues in the transmembrane domain of the proton-pumping pyridine nucleotide transhydrogenase of Escherichia coli

The pyridine nucleotide transhydrogenase carries out transmembrane proton translocation coupled to transfer of a hydride ion equivalent between NAD+ and NADP+. Previous workers (E. Holmberg et al. Biochemistry 33, 7691-7700, 1994; N. A. Glavas et al. Biochemistry 34, 7694-7702, 1995) had examined the role in proton translocation of conserved charged residues in the transmembrane domain. This study was extended to examine the role of conserved polar residues of the transmembrane domain. Site-directed mutagenesis of these residues did not produce major effects on hydride transfer or proton translocation activities except in the case of betaAsn222. Most mutants of this residue were drastically impaired in these activities. Three phenotypes were recognized. In betaN222C both activities were impaired maximally by 70%. The retention of proton translocation indicated that betaAsn222 was not directly involved in proton translocation. In betaN222H both activities were drastically reduced. Binding of NADP+ but not of NADPH was impaired. In betaN222R, by contrast, NADP+ remained tightly bound to the mutant transhydrogenase. It is concluded that betaAsn222, located in a transmembrane alpha-helix, is part of the conformational pathway by which NADP(H) binding, which occurs outside of the transmembrane domain, is coupled to proton translocation. Some nonconserved or semiconserved polar residues of the transmembrane domain were also examined by site-directed mutagenesis. Interaction of betaGlu124 with the proton translocation pathway is proposed.

[Low-tensioned and "b"-like ileocystoplasty]

OBJECTIVE

To perfectly solve the urine-kept and urinary problems of the vesical cancer patients after vesicoectomy.

METHODS

We performed low-tensioned and "b"-like ileocystoplasty in 16 patients.

RESULTS

After the operation, new vesica urinaria worked well in keeping and emptying urine-urine through the urethra. Residual urine test, chemical test and urography showed that there were no disturbance of body water and electrolyte metetabolism, no reterograde urine in the ureter, no uracratia, and no damage to renal function.

CONCLUSIONS

Ileocystoplasty can be used clinically.

[Clinical study of gentamycin-loaded chitosan drug delivery system]

An clinical and pharmacokinetic study for a drug delivery system (DDS) of gentamycin-loaded chitosan bar were carried out with the purpose to evaluate its efficacy and giving further data for its clinical applications. Eighteen cases of chronic osteomyelitis were treated by surgical necrectomy with implantation of gentamycin-load chitosan bar in the prepared bone cavity. After operation, the concentration of gentamycin in serum and wound drainage fluid were examined at different times and blood urea nitrogen (BUN) and serum creatinine (Cr) as well. The clinical results were evaluated by the conditions of wound healing and clinical and roentgenographic manifestations. The results showed that the serum gentamycin concentration reached its peak level (0.86 microgram/ml) at 24 hours after operation and lasted for 4 days. No increase in the concentrations of BUN and Cr were observed after implantation. The gentamycin concentration in wound drainage fluid was several hundred times higher than the minimum inhibitory concentration (MIC) for staphylococcus aureus. All of the 18 cases were followed up for 24.8 months (in an range of 6-34 months) 16 patients received initial cure and without any recurrence. So, it could be concluded that the gentamycin-loaded chitosan DDS was a simple and effective method for the treatment of chronic osteomylitis without the necessity to carry out a second operation to remove the drug carrier, and it was sound to popularize its clinical application.