Structural determinants for recognition and translocation by the anandamide transporter

The biological actions of anandamide (arachidonylethanolamide), an endogenous cannabinoid lipid, are terminated by a two-step inactivation process consisting of carrier-mediated uptake and intracellular hydrolysis. Anandamide uptake in neurons and astrocytes is mediated by a high-affinity, Na+-independent transporter that is selectively inhibited by N-(4-hydroxyphenyl)-arachidonamide (AM404). In the present study, we examined the structural determinants governing recognition and translocation of substrates by the anandamide transporter constitutively expressed in a human astrocytoma cell line. Competition experiments with a select group of analogs suggest that substrate recognition by the transporter is favored by a polar nonionizable head group of defined stereochemical configuration containing a hydroxyl moiety at its distal end. The secondary carboxamide group interacts favorably with the transporter, but may be replaced with either a tertiary amide or an ester, suggesting that it may serve as hydrogen acceptor. Thus, 2-arachidonylglycerol, a putative endogenous cannabinoid ester, also may serve as a substrate for the transporter. Substrate recognition requires the presence of at least one cis double bond situated at the middle of the fatty acid carbon chain, indicating a preference for ligands whose hydrophobic tail can adopt a bent U-shaped conformation. On the other hand, uptake experiments with radioactively labeled substrates show that no fewer than four cis nonconjugated double bonds are required for optimal translocation across the cell membrane, suggesting that substrates are transported in a folded hairpin conformation. These results outline the general structural requisites for anandamide transport and may assist in the development of selective inhibitors with potential clinical applications.

Ephedrine-induced complete atrioventricular block with ventricular asystole during rapid concomitant phenytoin infusion: a case report

Ephedrine is widely used to elevate blood pressure, however, one should be cautious to use it concomitantly with phenytoin infusion in neurosurgical procedures. A 59-year-old female was admitted for craniotomy with removal of metastatic brain tumor. During operation phenytoin infusion was given to forestall postoperative seizure. Hypotension, bradycardia and complete atrioventricular block followed by ventricular asystole suddenly occurred when the patient was given ephedrine to elevate the blood pressure to see the hemostatic effect close to the end of operation. We discontinued the phenytoin infusion and immediately injected 1.5 mg epinephrine. She was successfully resuscitated. We conclude that when phenytoin is used intraoperatively it should be administered by an infusion pump at a rate of less than 25 mg/min and under continuous monitoring of cardiac rhythm, heart rate, and blood pressure. When pressure support is required, the use of a pure alpha-agonist may minimize the risk of adverse reactions in the presence of phenytoin infusion.

Subtalar arthrodesis for late sequelae of calcaneal fractures: fusion in situ versus fusion with sliding corrective osteotomy

Primary subtalar arthritis is not common. In most cases, it is the late sequela of intra-articular calcaneal fracture. Subtalar arthrodesis is mostly used for the treatment of traumatic subtalar arthritis in our clinics. We have compared our early cases of in-situ subtalar fusion with our recent cases of fusion with sliding corrective osteotomy in this clinical report. From 1989 to 1992, 15 feet of 13 patients were treated with subtalar arthrodeses for subtalar arthritis caused by malunion of calcaneal fractures. Fusion in situ was done by Ollier's approach, and resection of bony protrusion was done if there was lateral entrapment syndrome. From 1992 to 1995, 13 feet of 12 patients also received subtalar arthrodeses to salvage their calcaneal fractures, but the subtalar fusion was done by wide lateral approach, calcaneal sliding corrective osteotomy, and sometimes (11 of 13 feet) with Achilles tendon lengthening to restore the calcaneal height and width. Patients of both groups experienced obvious clinical improvement in subtalar pain relief, but there was no difference with walking distance, running, or jumping. The group undergoing fusion with sliding corrective osteotomy was more satisfied with regard to cosmetic results and shoe wear. The overall satisfactory rate in the group who underwent fusion with sliding corrective osteotomy (92%) was superior to the group who underwent fusion in situ (77%). Though our method of sliding corrective osteotomy does not provide much improvement to the talus declination angle, it is suitable for those patients with a "banana"-shaped calcaneus malunion. If the patient has prominent anterior ankle pain caused by tibiotalar impingement, we believe that a distraction subtalar arthrodesis would be more appropriate.

UV-B-induced secondary conformational changes in lens alpha-crystallin

The changes in turbidity and protein secondary structure of alpha-crystallin after a 72 h UV-B (302 nm) irradiation in aqueous solution have been determined by UV spectrophotometry and Fourier transform infrared (FT-IR) microspectroscopy with reflection mode. The relative transmission of alpha-crystallin aqueous solution gradually decreases with the exposure time, indicating that the transparent alpha-crystallin aqueous solution becomes opaque with prolonged UV-B irradiation. The turbidity induced by UV-B shows first-order kinetics due to the photo-induced aggregation. The modification of the secondary structure of the alpha-crystallin molecule in aqueous solution caused by this aggregation might enhance the alpha-helix and beta-turn structures from 8.14 to 14.92% and from 24.46 to 35.54%, respectively; reduce the beta-sheet structure from 60.20% to 43.77%; and leave the random coil structure almost unaltered. The secondary conformation of alpha-crystallin changes gradually but evidently with its increase of turbidity during UV-B exposure.

pH-dependent secondary conformation of the peptide hormone leptin in different buffer solutions

The secondary structure of leptin in each different pH buffer solution (pH 5.35, 6.75, 7.58 and 8.45) was first determined by attenuated total reflection (ATR)/Fourier transform infrared (FT-IR) spectrometer with second-derivative, Fourier self-deconvolution and band curve-fitting methods to quantitatively estimate the secondary structure of leptin. The results indicate that pH induced more stretching vibration of CH2 and bending vibration of C-H and/or symmetric stretching of carboxylate of leptin structure in higher pH buffer solution than in lower pH buffer solution. Moreover, the band area of amide I for leptin in the higher pH buffer solution markedly enlarged, suggesting the amide I contour of leptin was very sensitive to pH to alter the secondary conformation of leptin structure. The structural component and composition of amide I band for leptin in both pH 6.75 and pH 7.58 buffer solutions were similar and had 50-52% helical structure including alpha-helix at 1654 cm-1 and 3(10)-helical structure at 1659-1667 cm-1 and 1640 cm-1. Although the secondary structure of leptin in pH 5.35 and 8.45 buffer solutions were also similar, a different structural information was obtained.

pH-dependent secondary conformation of bovine lens alpha-crystallin: ATR infrared spectroscopic study with second-derivative analysis

BACKGROUND

In order to simulate the usage of different formulations of ophthalmic solution, the protein conformational changes of lens alpha-crystallin in buffer solutions of different pH were investigated.

METHODS

The secondary structure of bovine lens alpha-crystallin in different Mcllvaine buffer solutions (pH 2.2, 4.0, 6.0, 7.2 and 8.0) was determined by attenuated total reflection (ATR)/Fourier transform infrared (FT-IR) spectrometry with second-derivative technique. The turbidity of alpha-crystallin in different buffer solutions was observed.

RESULTS AND CONCLUSION

The results indicate that alpha-crystallin exists mainly in beta-sheet structure at 1627-1637 cm-1. The conformational components of alpha-crystallin may be closely similar in pH 7.2 buffer solution and in pH 8.0 buffer solution. Once alpha-crystallin dissolved in pH 6.0 and 4.0 buffer solution, the appearance of a component at 1618 or 1620 cm-1, associated with the presence of intermolecular beta-sheet structure or beta-turn structure or amino acid side chains, implied the denaturation of alpha-crystallin, which was even more marked in pH 4.0 buffer solution. Due to the effect of dissociation and stability of alpha-crystallin in pH 2.2 buffer solution, the secondary structure of the intact alpha-crystallin was difficult to evaluate. This study demonstrates that different pH can vary secondary conformational structure of alpha-crystallin, particularly if the pH is below 6.0. This suggests that the secondary structure of alpha-crystallin in buffer solution exhibits pH-dependent characteristics.

Hürthle cell carcinoma of the thyroid gland with extensive tumor necrosis: a case report

Hürthle cell neoplasm of the thyroid gland is rarely associated with tumor necrosis. We report a case of Hürthle cell carcinoma of the thyroid gland with extensive necrosis. An 82-year-old man had had a right neck mass for more than 10 years. Approximately two to three weeks before he was hospitalized, this neck mass became progressively enlarged. An 131I scan could not demonstrate the right lobe of the thyroid gland, while the contralateral lobe was unremarkable. A 99mTc-sestamibi scan showed increased uptake on the lesion side. Fine needle aspiration cytology showed necrosis with macrophages in the initial aspirate, and the secondary aspirate appeared suspicious for a Hürthle cell tumor. The patient had a total thyroidectomy, and the pathology proved to be Hürthle cell carcinoma with tumor necrosis.

Analysis of aberrant transcription of TSG101 in hepatocellular carcinomas

A variety of studies suggest that tumour suppressor loci on chromosome 11p are important in various forms of human neoplasia. Recently, a gene located at the chromosome 11p 15.1-15.2 region called TSG101 was discovered and proposed as a candidate tumour suppressor gene in breast cancers. We evaluated the TSG101 gene in a panel of liver cancer cell lines and paired tumours and non-malignant tissues. In this study, four of the seven (57%) cell lines, eight of the 18 (44%) tumours and four of the 18 (22%) non-malignant liver tissues exhibited aberrant TSG101 transcripts by nested reverse transcription-polymerase chain reaction (RT-PCR) analysis. However, a normal-sized transcript without sequence abnormalities verified by single-stranded conformation polymorphism (SSCP) analysis was expressed at robust levels in all the cell lines and most of the tissue samples tested. In addition, Southern blot analysis could identify no genomic abnormalities of the gene. Our results suggest either that the TSG101 gene may not be involved in hepatocarcinogenesis or that it plays a role in the development and/or progress of hepatocellular carcinomas through an unusual mechanism.

Growth/cell cycle regulation of Sp1 phosphorylation

Sp1 sites can mediate growth/cell cycle induction of dihydrofolate reductase in late G1 (Jensen, D. E., Black, A. R. Swick, A. G., and Azizkhan, J. C. (1997) J. Cell. Biochem. 67, 24-31). To investigate mechanisms underlying this induction, effects of serum stimulation on regulation of Sp1 were examined. In Balb/c 3T3 cells, serum stimulation did not affect Sp1 synthesis or the relative binding of Sp1 family members to DNA; however, it did result in a rapid, approximately 2-fold increase in Sp1 levels and an approximately 3-fold increase in specific Sp1 phosphorylation in mid-G1. In normal human diploid fibroblasts, serum stimulation also increased Sp1 phosphorylation in mid-G1 but did not affect Sp1 levels. Therefore, Sp1 phosphorylation is regulated in a growth/cell cycle-dependent manner which correlates temporally with induction of dihydrofolate reductase transcription. Further studies revealed a kinase activity specifically associated with Sp1 in a growth-regulated manner. This activity is distinct from purified kinases previously shown to phosphorylate Sp1 in vitro and phosphorylates Sp1 between amino acids 612 and 678 in its C terminus, a region also phosphorylated in mid-G1 in vivo. Therefore, this study indicates that phosphorylation of the C terminus of Sp1 may play a role in the cell cycle regulation of its transcriptional activity.

Effect of protective colloids on the induction of polymorphic changes in indomethacin agglomerates after solvent evaporation from o/w emulsions

Indomethacin (IMC) agglomerates were prepared by the solvent evaporation process from o/w emulsions containing different protective colloids in the external aqueous solution. The types of protective colloids inducing the polymorphic transformation of IMC in the agglomerates without wall material were investigated. The composition and its polymorphs were evaluated from the X-ray diffraction patterns, IR spectra and DSC thermograms. The results indicate that when pectin, beta-cyclodextrin, sodium alginate or sodium dodecyl supphase acted as a protective colloid, the respective IMC agglomerates consisted only of the alpha form of IMC. When gelatin or hydroxypropyl methylcellulose was used as a protective colloid, the amorphous, alpha and gamma forms as well as methylene chloride solvates of IMC were found in the IMC agglomerates. There was only methylene chloride solvate of IMC with a small amount of amorphous form in the IMC agglomerates prepared from albumin as a protective colloid, while IMC agglomerates prepared from methylcellulose, polyvinyl alcohol or biosoluble polymer consisted of the mixture of amorphous and alpha forms, and methylene chloride solvate of IMC. When polyvinyl pyrrolidone was applied to act as a protective colloid, the mixture of methylene chloride solvate and gamma form of IMC with less quantity of amorphous form was found in its IMC agglomerates. This strongly suggests that the composition of IMC agglomerates prepared from the solvent evaporation process was significantly influenced by the type of protective colloids used.

Three-dimensional photonic crystal with a stop band from 1.35 to 1.95 microm

A combination of advanced silicon-processing techniques was used to create three-dimensional (3D) photonic crystals with a 180-nm minimum feature size. The resulting 3D crystal displayed a strong stop band at optical wavelengths from lambda=1.35 microm to lambda=1.95 microm . This is believed to be the smallest 3D crystal with a complete 3D photonic bandgap ever created.

Multiple truncated transcripts of TSG101 in gastrointestinal cancers

The candidate tumour suppressor gene TSG101, located on chromosome 11p15, has been associated with frequent intragenic deletion in uncultured primary human breast cancers. Using paired tumour and normal tissues from surgical specimens, we performed nested reverse transcriptase-polymerase chain reaction and direct sequencing to analyse TSG101 exons 1-6 from 32 gastric, 30 colorectal and 16 oesophageal cancers. Truncated transcripts, were found in both tumour and normal tissues from the stomach (15.6 and 12.5%), colon (13.3 and 3.3%) and oesophagus (25 and 25%). Multiple truncated transcripts in individual specimens were also observed. Two types of splicing patterns, one with three to six bases homology at the deletion junction (25.9%), the other with donor site 5' GT and acceptor site 3' AG (55.6%), were the most common patterns. We conclude that in gastrointestinal cancers, truncated transcripts of TSG101 gene occur not uncommonly and do so with a specific splicing pattern.

pH of preparations affecting the on-off drug penetration behavior through the thermo-responsive liquid crystal-embedded membrane

A liquid crystal (cholesteryl oleyl carbonate, COC)-embedded membrane with a controlled rate and higher reversibly thermo-responsive function was successfully fabricated by the vacuum filtration method. The aim of this study was to investigate the effect of the pH of aqueous solutions and gel preparations on the penetration of salbutamol sulfate through this thermo-responsive COC-embedded membrane. The results indicate that the on-off switching penetration behavior of salbutamol sulfate through the COC-embedded membrane in response to a repeatedly exchanging temperature cycle (10 <=> 25 degreesC) is not influenced by the pH of the medium. However, the pH-dependent ionization of salbutamol and the viscosity of the gel base, as well as the interaction between salbutamol and carbopol, might change the amount and the rate of salbutamol sulfate that penetrates across this COC-embedded membrane.

Experimental demonstration of guiding and bending of electromagnetic waves in a photonic crystal

The routing and interconnection of optical signals through narrow channels and around sharp corners are important for large-scale all-optical circuit applications. A recent computational result suggests that photonic crystals may offer a novel way of achieving this goal by providing a mechanism for guiding light that is fundamentally different from traditional index guiding. Waveguiding in a photonic crystal and near 100 percent transmission of electromagnetic waves around sharp 90 degree corners were observed experimentally. Bending radii were made smaller than one wavelength.

Effects of lid suturing and trans-scleral cryotherapy on ocular growth in a piglet model

PURPOSE

To study whether lid suturing can induce axial myopia and explore whether trans-scleral cryotherapy can affect ocular growth in piglets or not.

METHODS

A total of fourteen 2- to 3-week-old piglets were studied. Three groups were included: lid suture, cryotherapy, and both lid suture/cryotherapy groups. The lid suturing group (N = 6) was given lid suturing to produce visual deprivation. The cryotherapy group (N = 4) received trans-scleral cryotherapy 360 degrees to encircle anterior to the equator. Both treatment groups (N = 4) received both cryotherapy and lid suturing. The cycloplegic refraction, corneal power, biometric axial length, and intraocular pressure (IOP) were measured before the experiments and 4 months later.

RESULTS

Mild axial myopia was induced in five lid-sutured eyes of the lid suturing group. The ocular refraction and eye size of cryotherapy eyes were not different from the control eyes in the cryotherapy group. More myopia was found in all four piglets that received both cryotherapy and lid suturing.

CONCLUSIONS

Lid suturing can induce axial myopia; however, cryotherapy did not affect normal eye growth and did not prevent the development of lid suturing myopia in piglets.

Modified Mitchell osteotomy for hallux valgus

From 1988 to 1995, 96 patients (161 feet) underwent a modified Mitchell distal metatarsal osteotomy performed for mild-to-moderate hallux valgus. On AP x-rays of the standing foot, the average intermetatarsal angle was corrected from 15 degrees to 9 degrees, and the first metatarsophalangeal angles were corrected from an average of 41 degrees to 15 degrees. Criteria for evaluation of clinical results included relief of pain, appearance of foot, and shoe wear. After an average follow-up of 38 months, the overall satisfaction rate was 92.5%. Complications included 13 pin tract infections, two delayed unions, and two correction losses. The most common late sequela was transfer metatarsalgia of the lesser toes, which occurred in 20 feet (12.4%), leading to some dissatisfaction. The Mitchell osteotomy can be used on cases with less than 20 degrees of intermetatarsal angle, offering a stable construct with easy postoperative care.

Non-destructive analysis of the conformational changes in human lens lipid and protein structures of the immature cataracts associated with glaucoma

Previous study has supposed a possible mechanism of exacerbating cataract formation in cataractous human lens capsules induced by hypertension or glaucoma. To clarify the glaucoma-induced cataract formation of the eyes lens, changes in the human lens lipid and protein structures of immature cataractous patients with or without glaucoma were investigated. Two normal lenses, ten immature cataractous lenses without any complication and four immature cataractous lenses with glaucoma were used after surgical operation. Each de-capsulated human lens sample was sliced with a number 15 surgical blade. The intact nuclear lens regions were used for non-destructive analysis. The lens lipid and protein structures, as well as compositions of these lens samples, were determined using a Fourier transform infrared (FTIR) microspectroscopy with second-derivative, de-convolution and curve-fitting methods. The results indicate that the IR spectrum of glaucomatous lenses appeared as a shoulder only at 2853 cm-1, thus the composition of the symmetric CH2 stretching band at 2853 (2852) cm-1 decreased more significantly in glaucomatous lens to only one half of that in normal and immature cataractous lenses. The composition of the asymmetric CH3 stretching band at 2965 cm-1 for normal lens decreases markedly from 32 to 20% for immature cataractous lenses with or without glaucoma. The compositional ratio of component at 2965 cm-1 to component at 2928 (2930) cm-1 for normal lenses was about 0.702, and that ratio for cataractous lenses without glaucoma was 0.382 but for glaucomatous lenses was 0.377. The maximum peak position of amide I band for IR spectra of the normal lens, immature cataractous lenses without complications or glaucomatous lenses appeared respectively at 1632, 1630 or 1622 cm-1, assigned to beta sheet structure. A marked difference in peak intensity of amide I band for the normal lenses and immature cataractous human lenses with or without glaucoma was observed. The peak intensity ratio of amide I/amide II (1632/1545 cm-1) for normal lenses was in the range of 2.20-2.33, whereas in the spectra of immature cataractous lenses without glaucoma this ratio (1630/1545 cm-1) was 1.28-1.41 but was 1.04-1.13 for glaucomatous lens in the intensity ratio of 1622/1545 cm-1. The intensity of the glycogen bands in the wavenumber region 1135-1076 and 1069-1032 cm-1 was found to increase for the immature cataractous lenses with or without glaucoma, as compared with the normal ones. The peaks ranging from 1633 to 1610 cm-1 assigned to beta-sheet structure also exhibited a pronounced compositional difference, particularly in glaucomatous lenses. The human lens lipid and protein secondary structures were more affected by glaucoma. Higher protein side chains and reduced lipid content contributed predominantly to the CH stretching vibrations of normal lens structure, whereas high lipid content and less protein side chains dominated the CH stretching vibrations of cataractous lenses with or without glaucoma. Decrease alpha-helix and random coil structures but enhanced beta-sheet structure in the immature cataractous human lens induced by glaucoma might result from the formation of intermolecular hydrogen-bonding insoluble protein aggregates that modify the secondary structure of protein in lenses.

NMDA receptor subunits in the postsynaptic density of rat brain: expression and phosphorylation by endogenous protein kinases

N-methyl-D-aspartate (NMDA) receptors (NRs) play critical roles in diverse synaptic processes in the brain. However, subcellular distribution, spatiotemporal expression and regulation of NR subunits in brain synapses are unknown. We report that NR1 and NR2A-2C subunits are all enriched in the postsynaptic density (PSD), which plays critical roles in trophin-mediated synaptic plasticity. Significant expression of NRs was observed the first two weeks after birth, during synaptogenesis, and in adulthood. Functional diversity of NRs, resulting from heterogeneous composition, was supported by the finding that different NR2 subunits were associated in a region-specific manner with NR1. Phosphorylation of NR1, a key subunit of the NMDA receptor-channel complex, was significantly enhanced by activators of calmodulin (CaM) kinases (CKs) or protein kinase C (PKC), but not by those of PKA. Co-immunoprecipitation studies revealed that NR1 was physically associated with functionally active PKCgamma and the major PSD protein (mPSDp) through noncovalent interactions. Our results suggest that NMDA receptors play roles in postsynaptic mechanisms in a subunit-, composition-, brain region- and developmental-specific manner. Our findings also indicate that the PSD is a coherent functional unit containing protein kinases that potentially regulate NMDA receptor function via phosphorylation.

Thermal stability and reversibility of secondary conformation of alpha-crystallin membrane during repeated heating processes

Reflectance FT-IR/DSC microspectroscopy was first used to study the structural conformation of alpha-crystallin membranes in the heating-cooling-reheating cycle. The thermotropic transition and the changes in secondary structure of alpha-crystallin membrane during heating and reheating processes were investigated. A thermal transition ranging between 50 and 70 degrees C with a midpoint at 60 degrees C for the alpha-crystallin membrane was easily obtained from the three-dimensional plots of the reflectance FT-IR spectra as a function of temperature. The secondary structural components of the alpha-crystallin membrane were modified step-by-step with the increase of temperature from 25 to 120 degrees C, but restored to original values after cooling to 25 degrees C. During the heating process, the compositions of the alpha-helix, random coil and beta-sheet structure decreased with temperature, but the content of the beta-turn structure increased, however, all of them were restored after cooling. The absence of significant alteration in the secondary structures for the alpha-crystallin membrane before and after the first-heating process strongly suggests the high thermal stability and reversibility of alpha-crystallin. Interestingly, the thermal behavior of the first-heated alpha-crystallin membrane during the reheating process exhibited a unique thermal behavior with two transitional temperatures at 35-50 and 55-70 degrees C. The reflectance FT-IR/DSC microscopic data indicated that alpha-crystallin in the membrane state had higher thermal stability and reversibility.

Effect of drug-polymer interaction on the release characteristics of methacrylic acid copolymer microcapsules containing theophylline

Theophylline anhydrate microcapsules with different amounts of MA/MMA copolymer (Eudragit L) were prepared by the solvent evaporation method. Qualitative as well as quantitative investigation of the drug-polymer interaction by Fourier transform infrared (FTIR) spectroscopy with a curve fitting program was undertaken. The release mechanisms of theophylline in pH 1.2 and pH 6.8 media were also studied to elucidate the effect of drug-polymer interaction on the release characteristics of microcapsules. Direct evidence for a hydrogen bonding interaction between theophylline and Eudragit L in microcapsules was obtained. Moreover, the fraction of hydrogen bonded theophylline increased with the increase of Eudragit L. The dissolution of theophylline from microcapsules exhibited an enteric-coated release property. The drug release mechanism was found to fit the Higuchi matrix model in the simulated gastric acid condition, but drug release was much more rapid in the pH 6.8 buffer solution. The drug release rate decreased as the composition of theophylline increased, and it was proportional to the fraction of hydrogen bonded theophylline. These results suggest that the increased fraction of hydrogen bonded theophylline in microencapsulation might improve the mixing and dispersibility of theophylline in the Eudragit L matrix, thus resulting in the increase of the release rate of theophylline from microcapsules.

Clinical study of failure in continuous spinal anesthesia with bupivacaine

BACKGROUND

Continuous spinal anesthesia (CSA) has been considered to be better in temporal and dose flexibility, as well as hemodynamic stability than single dose spinal anesthesia. However, the failure of spinal anesthesia is not a rare experience for anesthesiologists. Here we present our experience in solving the problem and discuss the possible causes for the failure.

METHODS

236 cases were studied retrospectively from January to December in 1996. All were over 65 years old, ASA III, scheduled for transurethral procedures or orthopedic operation. CSA was performed with 0.2% bupivacaine. Failed CSA was confirmed by positive pin-prick test at T10 dermatome(umbilicus) 30 minutes after 20 mg bupivacaine was injected. For failed cases, 5 mL 1% lidocaine was injected intrathecally for rescue. The failure rate, sensory and motor blockade, success rate by changing to lidocaine and its dosage were recorded.

RESULTS

Eleven of 236 cases (4.7%) were considered spinal failure since the initial 20 mg bupivacaine could not provide adequate T10 anesthesia in 30 minutes. Addition of 5 mL 1% lidocaine produced a profound sensory and motor blockade in 9 cases, while further lidocaine injection was required in two cases. The success rate by rescuing lidocaine was 100% with an average lidocaine consumption by 52.5 +/- 4.5 mg.

DISCUSSION

Factors contributed to failure spinal anesthesia including failure of technique, errors of judgment, maldistribution and failure of local anesthetic itself. However, we thought that change of pH value of local anesthetic in CSF may play a great part in these failed CSAs. Despite the reasons for failure, we demonstrate that failure of continuous spinal anesthesia by 0.2% bupivacaine can be readily resolved by 1% lidocaine.

Integrality of benign prostatic hyperplasia tissues after transurethral thermotherapy evidenced by transmittance fourier transform infrared spectroscopy combined with thermal analyzer

Transmittance Fourier transform infrared microspectroscopy combined with differential scanning calorimetry was used to simulate the clinically transurethral thermotherapy of benign prostatic hyperplasia (BPH) by in vitro isothermal determination. The simulative study to the thermotherapy of epithelium or stroma in BPH tissue was performed at 47 degrees C for 3 h, like clinical therapy. Whether thermal treatment can induce changes in the secondary structure of epithelium or stroma in BPH tissue was investigated. The results indicate that the epithelium and stroma in BPH tissue had different protein secondary structures, due to the different compositions of the epithelium and stroma. No significant change was evidenced in secondary structure for each sample either before or after isothermal study, suggesting the integrality and safety of BPH thermotherapy in a 47 degrees C for 3 h treatment course.

Assessment of protein conformation in human benign and malignant astrocytomas by reflectance Fourier transform infrared microspectroscopy

The secondary structure and composition of protein in the tissues of benign and malignant astrocytomas were determined by reflectance Fourier-transform infrared (FT-IR) microspectroscopy. The peak maximum of IR spectra of the tissues from recurrent malignant astrocytoma markedly appeared at higher frequency (1655 or 1663 cm(-1)), which was significantly different from that of the tissues from benign astrocytoma at 1651 cm(-1) and tissues from malignant astrocytoma at 1652 cm(-1). Malignant astrocytoma indicated slightly different compositions in the protein secondary structure from benign astrocytoma. However, a significant increase in beta-turn structure but a marked decrease in beta-sheet and random coil structures were observed in the protein secondary structure of the recurrent malignant astrocytoma. The phenomenon was more pronounced in recurrent malignant astrocytoma pretreated with radiation and chemotherapy. The rapid cell proliferation and cell differentiation of malignant astrocytoma with or without recurrence might be the possible explanations for the different compositions of protein conformational structures.

Glimpses at the recognition of peptide/MHC complexes by T-cell antigen receptors

More than a decade after the first description of the primary structure of a T-cell antigen receptor (TCR), the recent determination of the crystal structure of several unliganded TCR ectodomains and of two TCRs complexed to peptide-MHC ligand provides a structural basis for understanding the initial event that triggers T-cell activation. This review focuses on the topology of the variable (V) domains found in TCRs and immunoglobulins and attempts to delineate the structural features that may render the TCR complementarity-determining regions particularly suited to dock on the peptide/MHC surface. Finally, the available TCR structures provide an opportunity to re-evaluate the molecular basis for intrathymic positive selection as well as the mechanisms that make a given TCR neither infinitely specific, nor so flexible that it engages productively any MHC-binding peptides.

Acinetobacter calcoaceticus-baumannii complex bacteremia: analysis of 82 cases

Eighty-two cases of Acinetobacter calcoaceticus-baumannii complex bacteremia were identified during a 33-month period, from November 1993 to July 1996, at the Veterans General Hospital, Taipei. All cases were due to hospital-acquired infections, with 28 cases of polymicrobial bacteremia. Most patients had severe debilitating conditions: 26 had malignancies, 40 required stay in Intensive Care Unit and 17 had undergone major operations. The main predisposing factors included central venous catheterization, endotracheal intubation or tracheostomy, prior antibiotic therapy and prolonged hospitalization. Amikacin, tobramycin, and ceftazidime were the most effective agents in vitro against A. calcoaceticus-baumannii complex. 32 patients (39 %) died during hospitalization, 19 of the cases (23 %) directly attributed to septicemia. Factors that adversely influenced mortality included polymicrobial bacteremia, inappropriate antimicrobial therapy and prior antibiotic treatment. Of particular interest is the fact that none of the patients who did not receive appropriate antimicrobial therapy survived. Early diagnosis and appropriate antibiotic therapy are critical for improving the prognosis of A. calcoaceticus-baumannii complex bacteremia.

Suppression of sprouting: An early function of NMDA receptors in the absence of AMPA/kainate receptor activity

Electrophysiological studies have documented the existence of synapses showing only NMDA ionotropic glutamate receptor function that are therefore presumably "silent" at resting membrane potentials. Silent synapses are more prevalent in young than in older neurons, and NMDA receptor activity at such contacts may facilitate the appearance of functional AMPA receptors. However, it is uncertain whether such silent synapses actually have a function in young neurons independent of AMPA receptor induction. Using a newly characterized culture system for neurons from larval Xenopus tecta, we show that blocking NMDA receptors or preventing changes in intracellular free Ca2+ concentration with BAPTA AM significantly increases neurite sprouting and elongation in contacted but not in isolated neurons. Blocking AMPA/KA receptors or Na+-dependent action potentials does not mimic this effect. Moreover, in these young neurons, NMDA receptor-dependent Ca2+ responses to glutamate measured with confocal fluo-3 imaging are retained during AMPA/KA receptor blockade. The data suggest that many of the young contacts in these cultures are active even though they use only NMDA ionotropic glutamate receptors. Calcium influx through the NMDA receptor at these contacts seems to reduce neurite motility. This effect should lead to the accumulation of glutamatergic inputs on NMDA receptor-expressing dendrites, which could facilitate the onset of AMPA/KA receptor function and the action potential-dependent phase of synaptogenesis.

A detailed characterization of the effects of four cannabinoid agonists on operant lever pressing

The present experiments were conducted to investigate the effects of four cannabimimetics on detailed temporal parameters of operant responding. In this study, the behavioral output during performance of a fixed ratio 5 schedule of reinforcement was recorded by a computer program that measured the response initiation time (IT; time interval between the offset of one lever press and the onset of the next) and the response duration (the amount of time that elapses from the onset to the offset of one lever press) of each lever press. ITs were further partitioned into fast responses (IT=0.0-1.0 s), short pauses (IT= 1.0-2.5 s), and long pauses (IT>2.5 s). Four cannabimimetic agents were assessed in this study: (R)-methanandamide (AM 356), a hydrolytically stable analog of arachidonylethanolamide, an endogenous ligand for the CB1 receptor; CP-55,940, a potent non-classical synthetic ligand; (-)-delta8-tetrahydrocannabinol (delta8-THC), an isomer of the naturally occurring delta9-THC; and WIN 55,212-2, a synthetic aminoalkylindole. All four of the cannabimimetic drugs tested significantly suppressed operant lever pressing in a dose dependent manner. The rank order of potencies observed in the present study was CP-55,940>>WIN-55,212-2>delta8-THC>AM 356, which is consistent with the rank order of affinities for the CB1 receptor shown by these drugs. All of the cannabimimetics substantially increased average IT, and also increased duration time. There was a substantial increase in average length of long pauses, and statistically significant but very small changes in the local rate of responding as measured by the average length of fast ITs. Cannabinoid-treated rats were largely immobile during pauses in responding, and these animals showed several signs of ataxia and catalepsy at the doses that suppressed lever pressing. Together with other data, the present results suggest that CB1 stimulation leads to motor effects that are associated with a suppression of lever pressing.

Functionality of protective colloids affecting the formation, size uniformity and morphology of drug-free polylactic acid microspheres

Drug-free polylactic acid (PLA) microspheres were prepared by an emulsification-solvent evaporation technique using different types of protective colloids. The influence of five types of hydrophilic prolymers (polysaccharides, proteins, synthetic cellulose derivatives, synthetic nonionic polymers and surfactants) on the formation, size uniformity and morphology of PLA microspheres was investigated. Four characteristic functions (surface activity, viscosity, electric charge and interfacial film formation) of the hydrophilic polymer aqueous solutions were used to evaluate the efficacy of these protective colloids used. The results indicate that these four functions were the key parameters to achieve the formation of PLA microspheres. The best protective colloid should have high surface activity, optimum viscosity, adequate electric charge, and form an interfacial film to give a higher recovery, better size uniformity and smoother topography of the PLA microspheres.

Chemical denaturation of ovalbumin abrogates the induction of oral tolerance of mouse reaginic antibody responses

The effect of chemical denaturation of ovalbumin (OVA) on the induction of oral tolerance of reaginic antibody responses was studied. Both urea-denatured OVA (UD-OVA) and carboxymethylated UD-OVA (CM-OVA) were purified by centrifugation. When compared with OVA and UD-OVA, CM-OVA had the least sensitizing capacity and allergenicity in IgE responses to OVA. BALB/c IgE, IgG1 and IgG antibody responses were suppressed by OVA, but not by UD-OVA or CM-OVA, fed prior to sensitization with OVA, UD-OVA, or CM-OVA in alum, respectively. The priming effect of specific IgG and IgG1 antibody responses was induced by CM-OVA fed prior to sensitization with OVA or CM-OVA. The proliferation of BALB/c spleen cells and their secretion of T helper type 2 (Th2) cytokines interleukin-4 (IL-4) and IL-5 were also orally tolerized by OVA, but not by denatured OVA. Although denatured OVA is hypoallergenic, the present result indicates that denaturation of a soluble protein prevents the induction of oral tolerance of Th2 responses.

Modified Blair method for ankle arthrodesis

In this study, the ordinary Blair's ankle arthrodesis was modified by longitudinal oblique cutting to get the sliding bone graft, up side down grafting, and additional screw fixation at talar site with or without staples fixation of tibia-talar junction. The method of ankle arthrodesis was used on 34 cases from 1987 to 1990 with a 91.2% fusion rate and an average 5.6 months fusion time. The oblique cut bone graft provided larger contact surface to enhance bony fusion and the upside-down bone graft provided stronger tibia-talar bone bridge with thicker cortex for distal screw fixation and the distal screw fixation of bone graft to talus had the advantage of securing union and maintaining position. With such modifications, solid ankle arthrodesis could be obtained even without interarticular compression.

BDNF acutely increases tyrosine phosphorylation of the NMDA receptor subunit 2B in cortical and hippocampal postsynaptic densities

While neurotrophins are critical for neuronal survival and differentiation, recent work suggests that they acutely regulate synaptic transmission as well. Brain-derived neurotrophic factor (BDNF) enhances excitatory postsynaptic currents in cultured dissociated hippocampal neurons within 2-3 min through postsynaptic, phosphorylation-dependent mechanisms. Moreover, BDNF modulates hippocampal long-term potentiation, in which postsynaptic NMDA (N-methyl-D-aspartate) receptors (NRs) play a key role. We now report that BDNF acutely increases tyrosine phosphorylation of the specific NMDA receptor subunit NR2B, which has recently been shown to play a role in long-term potentiation. Incubation of BDNF with cortical or hippocampal postsynaptic densities for 5 min increased tyrosine phosphorylation of the NR2B subunits in a dose-dependent manner. A maximal increase to 165% of control phosphorylation occurred at a BDNF concentration of 2 ng/ml. The BDNF action appeared to be specific, since nerve growth factor, another member of the neurotrophin gene family, had no effect on NR2B phosphorylation. Further, BDNF action was selective, since it did not alter tyrosine phosphorylation of NR2A subunits. Our results suggest that tyrosine phosphorylation of NR2B subunits of the NMDA receptor may contribute to neurotrophin modulation of postsynaptic responsiveness and long-term potentiation.

Reproducibility of the revised American Fertility Society classification of endometriosis using laparoscopy or laparotomy

OBJECTIVE

To assess the discrepancy between laparoscopic and laparotomic scoring methods using the revised American Fertility Society (AFS) classification of endometriosis.

METHOD

In this prospective study, 84 patients with endometriosis were scored twice (laparoscopically and laparotomically) by the same subspecialty-certified reproductive endocrinologist. The magnitude of inter-method variability was reported quantitatively by the S.D. of the differences in scores between the pairs. The differences in the mean endometriosis scores between the two methods were assessed by the paired Student's t-test. P < 0.05 was considered as statistically significant. Discrepancy between the two methods in the staging of endometriosis patients was presented by kappa measure of agreement.

RESULT

There was considerable variability in the scores between the two scoring methods by the same observer. Among individual components of the scoring system, the greatest variability occurred in the ovarian endometriosis and cul-de-sac obliteration subscores, with the least variability observed for peritoneum endometriosis. The inter-method variation in score was sufficient to alter the endometriosis staging in 34.5% of patients, including a difference of two stages in 3.6% of patients. The kappa coefficient was 0.49, indicating fair-to-good agreement between the two scoring methods.

CONCLUSION

Inter-method variability between laparoscopic and laparotomic scoring methods was high for ovarian endometriosis subscore using the revised AFS classification of endometriosis. Agreement in endometriosis staging between the two methods was fair to good.

Genitourinary tuberculosis complicated with adrenal involvement and primary adrenocortical insufficiency: a case report

Genitourinary tuberculosis (TB) rarely involves the adrenal gland. A 67-year-old man presented with progressively hyperpigmented skin and an enlarged mass over both testes. Early morning plasma cortisol concentration was low and adrenocorticotropic hormone (ACTH) concentration was high. A rapid ACTH stimulation test revealed the absence of plasma cortisol response and confirmed a diagnosis of primary adrenocortical insufficiency. An abdomen computed tomography (CT) scan disclosed enlargement of the right adrenal gland and punctuate calcification over the left one. This is compatible with tuberculous adrenalitis. Currettage biopsy of the prostate demonstrated chronic granulomatous inflammation with Langerhan's giant cells, but without TB bacilli. Anti-TB treatment, in addition to glucocorticoid and mineralocorticoid replacement, was administered. The testicular mass decreased progressively though the results of a subsequent ACTH stimulation test, six months later, disclosed no significant change. A follow-up CT scan, one and a half years later, showed a decrease in the size of the right adrenal mass.

Primary left atrial malignant mesenchymoma: a case report

Primary malignant mesenchymoma involving the heart is extremely rare. It usually has a poor prognosis. We report a case of malignant mesenchymoma originating in the left atrium with protrusion into the right pulmonary veins. Clinically, this patient presented with congestive heart failure, hemoptysis and systemic arterial embolization. Transthoracic and transesophageal echocardiography revealed a huge mass originating in the posterior wall of the left atrium with extension into both upper and lower right pulmonary veins. An elevated pulmonary arterial wedge pressure, moderate pulmonary hypertension and stenosis of the lower abdominal aorta were found during cardiac catheterization. Magnetic resonance imaging with angiography disclosed a tumor mass over the abdominal aorta above the bifurcation with protrusion into the right common iliac artery. This patient underwent surgical resection of the cardiac tumor and postoperative adjuvant chemotherapy. The pathological finding of a tumor containing several cellular types of sarcoma confirmed the diagnosis of malignant mesenchymoma.

Ankle arthrography and chronic lateral ankle instability

Sixty-five ankle arthrograms of the patients who underwent surgical reconstruction for their chronic ankle instability from 1987 to 1995 were studied retrospectively by comparing their operative findings. There were 15 cases (23.1%) with definite positive arthrographic findings. In the remaining 50 cases (76.9%), the arthrograms showed a "tear-drop" extravasation of dye beneath the fibular tip which we called "suspectable positive". Of these all but one, which had normal ligament, proved to correspond to the operative finding. As there was only one false positive finding among our surgical cases with both the "definite" and "suspectable" positive arthrograms, we concluded that ankle arthrography is relatively reliable and may be worth doing even in chronic cases if only for reference. Even when other diagnostic methods are negative, arthrography might help surgeons make surgical decisions in clinical symptomatic cases.

Long-term epidural ketamine, morphine and bupivacaine attenuate reflex sympathetic dystrophy neuralgia

PURPOSE

There is considerable evidence that NMDA receptor antagonists can abolish nociceptor hypersensitivity in animals. In the present case report, two patients with reflex sympathetic dystrophy were treated with ketamine, a NMDA antagonist, morphine and bupivacaine.

CLINICAL FEATURES

Two patients were referred suffering from severe pain, allodynia, hyperaesthesia, swelling and disability over their right lower legs, diagnosed as reflex sympathetic dystrophy. They had received conventional treatments with non-steroid anti-inflammatory drugs (NSAIDs), steroids, anticonvulsant, antidepressant, epidural lidocaine sympathetectomy and rehabilitation which failed to provide satisfactory pain relief. We administered subanalgesic doses of ketamine (7.5 mg), morphine (0.75 mg) and 6 ml bupivacaine 0.1% via a lumbar epidural catheter three times per day. After several courses of treatment over three and six months, satisfactory pain relief was achieved in each patient. Both are now able to walk with slight weight bearing with the assistance of crutch. The treatment is continuing with further improvement of symptoms and signs.

CONCLUSION

Epidural coadministration of low doses of morphine, ketamine and bupivacaine provided effective pain relief in two patients. This suggests synergy from this combination that provides an alternative treatment for reflex sympathetic dystrophy.

In vitro simulation of thermotherapy for benign prostatic hyperplasia by Fourier transform infrared microspectroscopy combined with differential scanning calorimetry

Thermo-dependent changes in the secondary structure of the epithelium and stroma of benign prostatic hyperplasia (BPH) were investigated by Fourier transform infrared (FT-IR) microspectroscopy combined with differential scanning calorimetry (DSC). This microscopic FT-IR/DSC system was used to simulate transurethral thermotherapy for BPH in vitro. The results indicate that thermal-induced conversion from an alpha helix to a beta structure was found in the epithelium and stroma of BPH. However, this thermal-induced conversion behavior in the stroma was less sensitive than that in the epithelium during thermal treatment. The different thermal response between the epithelium and stroma of BPH might be due to the different constitutions of the epithelium and stroma of BPH.

Surgical treatment for pilon fracture of the ankle-open reduction and internal fixation

From 1991 to 1994, 39 ankles of 38 patients underwent surgical open reduction and internal fixation for pilon fractures. These patients included 29 males and 9 females with an average age of 38.6 y/o (range 28 y/o-58 y/o). The follow up and evaluation period averaged 31.7 months (range 22Ms-44Ms), during which time a standing x-ray for arthrosis grading and functional scale was used for clinical evaluation. Complications included 1 case of infection, 1 case of loss reduction, 2 cases of partial skin necrosis and 2 cases of delayed union. Post-traumatic arthritis occurred in 23 ankles (59%) but only 4 ankles of grade 4 arthrosis resulted in poor functional scale and the overall satisfactory rate was 82%. It was found that anatomic reduction, rigid fixation and early motion exercise are important to successful treatment of ankle fractures. Regarding pilon fracture, specifically the severity of fracture pattern and delay of reduction are important problems to overcome to ensure successful results. Therefore, adequate surgical approach for entire view of ankle joint, reduction and fixation of fibula, sufficient bone graft for articular support, intraoperative x-ray check and postoperative immobilization are essential for the achievement of better clinical results.

A high-density rice genetic linkage map with 2275 markers using a single F2 population

A 2275-marker genetic map of rice (Oryza sativa L.) covering 1521.6 cM in the Kosambi function has been constructed using 186 F2 plants from a single cross between the japonica variety Nipponbare and the indica variety Kasalath. The map provides the most detailed and informative genetic map of any plant. Centromere locations on 12 linkage groups were determined by dosage analysis of secondary and telotrisomics using > 130 DNA markers located on respective chromosome arms. A limited influence on meiotic recombination inhibition by the centromere in the genetic map was discussed. The main sources of the markers in this map were expressed sequence tag (EST) clones from Nipponbare callus, root, and shoot libraries. We mapped 1455 loci using ESTs; 615 of these loci showed significant similarities to known genes, including single-copy genes, family genes, and isozyme genes. The high-resolution genetic map permitted us to characterize meiotic recombinations in the whole genome. Positive interference of meiotic recombination was detected both by the distribution of recombination number per each chromosome and by the distribution of double crossover interval lengths.

Inhibition of intestinal motility by anandamide, an endogenous cannabinoid

The endogenous cannabinoid ligand anandamide (arachidonylethanolamide) inhibited the intestinal passage of a charcoal meal when administered s.c. in mice at doses ranging from 0.1 to 50 mg/kg. This effect was prevented by the cannabinoid CB1 receptor antagonist SR141716A [N-(piperidin-1-yl)-5-(4-chlorophenyl)-1-(2,4-dichlorophenyl)-4-me thyl-1H-pyrazole-3-carboxamide x HCl] (1 mg/kg s.c.), but it was not affected by the anandamide transport inhibitor, N-(4-hydroxyphenyl) arachidonylethanolamide (AM404) (50 mg/kg, s.c.). The results indicate that anandamide modulates intestinal motility in mice by activating cannabinoid CB1 receptors. They also suggest that anandamide transport, which was previously shown to participate in terminating neural and vascular responses to anandamide, does not contribute to anandamide inactivation in intestinal tissue.

Subtalar arthrodesis for subtalar arthritis

Primary subtalar arthritis is not common except in cases of generalized arthritis such as rheumatoid arthritis. The majority of subtalar arthritis results from intraarticular calcaneal fractures. Arthrodesis seems to be the only way to solve this problem. Thirteen patients (15 feet) were treated with subtalar arthrodesis at KMCH. Preoperative diagnosis included 13 feet with traumatic arthritis secondary to a calcaneal fracture, one foot with rheumatoid arthritis and one foot with primary osteoarthritis. The mean follow up period was 24.9 months. Lateral approach without fibular osteotomy was done with decompression if there was entrapment syndrome and the arthrodesis were accomplished with use of staples for internal fixation. Eleven (85%) of the patients were satisfied with the results. Objectively, the results were excellent after 11 arthrodesis (73%), good or fair after three (20%), and poor after one (7%). There was no nonunion. Complications occurred in 1 patient who developed superficial wound infection, and in 1 patient with staple loosening. Though there was no case of nonunion, the fusion time was rather long. This might have been due to the fixation method because staples can not provide compression force which accelerates union. We believe subtalar arthrodesis is appropriate for isolated subtalar arthritis unless there are associated talonavicular or calcaneocuboid arthritis in which case triple arthrodesis will be more appropriate.

Infra-red (ATR/FT) spectroscopic study on the conformational structure of the isolated human gastric mucus pretreated with ethanol

In order to investigate the conformational structure of isolated human gastric mucus gel pretreated with or without ethanol, gel samples were determined by attenuated total reflection/Fourier transform-infra-red (ATR/FT-IR) microspectroscopy. The result indicates that the secondary structure-dependent amide I band and the glycoprotein region were significantly different in the gastric mucus gels pretreated with and without 40% ethanol. The structural composition of beta-sheet structure (1640-1600 cm-1) increased from 38.48 to 55.08% (+16.6%) after 6-hour pretreatment with 40% ethanol, but the beta-turn structure, (1660-1700 cm-1) decreased from 41.38 to 24.29% (-17.05%). The peak area ranging from 1180 to 1000 cm-1, assigned to the glycoprotein region, was also different after pretreatment with ethanol for 6 h. The higher peak area of the carbohydrate band was obtained in the frequency region between 1000 and 1040 cm-1 and 1100 and 1180 cm-1 for mucus gel pretreated with 40% ethanol. However, the peak area ranging from 1100 to 1040 cm-1 mainly due to the symmetric phosphate stretching mode of proteins was somewhat lower for the ethanol-pretreated mucus gel than the native mucus gel. This result strongly reveals that ethanol significantly modified the conformational structure of proteins and carbohydrates of gastric mucus gel. We propose that the dehydration and interference of hydrophobic interactions in the isolated mucus gel after pretreatment with ethanol might be responsible for this conformational change.

Salvage operation for neglected ankle fractures

From 1986 to 1993, 49 cases of untreated or poorly treated ankle fractures who received salvage surgery were followed up for an average of 36.4 months. The patients included 31 males & 18 females with an average age of 41.6y/o and the time interval from initial injury to reconstructive surgery average due 17.6 months. They were classified and treated according to their grade of reduction and degree of arthrosis. The surgical methods included arthrotomy & joint debridement, revised open reduction, lower tibial osteotomy and ankle arthrodesis, depending on different individual conditions. After surgery, all cases had symptomatic relief and functional improvement with an average score increased from 26.3 preoperatively to 86.8 at follow up. The goals of ankle fractures is as articular fractures, they are treated by surgical anatomic reduction with rigid fixation as early as possible in order to provide good functional results. Nevertheless they are varied in neglected ankle fractures according to their individual conditions: open reductions were performed on cases with no or little arthritic change even though arthrosis might occur later because, if necessary, future conversion to osteotomy or arthrodesis would be easier. As for late cases with advanced arthritis, ankle arthrodesis were done by compressive arthrodesis with necessary bone graft to secure fusion in an optimal position.

Conformational changes in gastric carcinoma cell membrane protein correlated to cell viability after treatment with adamantyl maleimide

BACKGROUND

In order to investigate the mechanism of the effects of the anticancer drug adamantyl maleimide (AMI) on the in vitro growth of a human gastric carcinoma cell line (SC-M1), the membrane protein conformation on the cell surface after treatment with AMI was studied.

MATERIALS AND METHODS

The interaction of AMI with SC-M1 cell line was studied by reflectance Fourier transform infrared (FT-IR) microspectroscopy. The cell viability was also determined by the trypan blue exclusion method.

RESULTS

FT-IR microscopic study provided evidence that the conformational conversion of the membrane proteins of the SC-M1 cell line from alpha-helix to beta-sheet was found evident, but was dependent on the AMI concentrations used and the time of treatment. AMI not only interacted with the membrane protein on the cell surface, but also entered into cells to interact with the nucleic acids.

CONCLUSIONS

The relationship between membrane protein conformational changes and the cell viability of SC-M1 cell line was evident. The AMI-induced apoptosis in SC-M1 cell line was also supposed.

Surgical treatment of pathologic fracture of the femur

A retrospective study of the surgical treatment of 32 metastatic lesions of the femur in 30 patients at the Kaohsiung Medical College Hospital was performed from 1987 to 1994. There were 16 women and 14 men with an average age of 61 years. A surgical technique combining internal fixation or prosthesis and methylmethacrylate cement was used in all cases. Adequate pain relief was achieved in thirty-one cases (97 %). Of the entire group, 20 cases (62%) remained ambulatory, 10 cases (31%) were confined to a wheelchair, only two cases had implant failure and one suffered from infection.

Functional role of high-affinity anandamide transport, as revealed by selective inhibition

Anandamide, an endogenous ligand for central cannabinoid receptors, is released from neurons on depolarization and rapidly inactivated. Anandamide inactivation is not completely understood, but it may occur by transport into cells or by enzymatic hydrolysis. The compound N-(4-hydroxyphenyl)arachidonylamide (AM404) was shown to inhibit high-affinity anandamide accumulation in rat neurons and astrocytes in vitro, an indication that this accumulation resulted from carrier-mediated transport. Although AM404 did not activate cannabinoid receptors or inhibit anandamide hydrolysis, it enhanced receptor-mediated anandamide responses in vitro and in vivo. The data indicate that carrier-mediated transport may be essential for termination of the biological effects of anandamide, and may represent a potential drug target.

Differentiation of the maturity of cataractous human lens capsules according to changes in protein secondary structures determined by Fourier-transformed infrared spectroscopy

PURPOSE

Cataract-induced alterations in the protein secondary structure of human lens capsules in different maturity of cataractous patients was investigated.

METHODS

Fourier-transformed infrared (FT-IR) spectroscopy with Fourier self-deconvolution and curve-fitting algorithms was used. Twenty-seven immature and four mature cataractous patients (previously classified through observations of the depth of the shadow cast by the iris on oblique illumination) were investigated in the present study.

RESULTS

Two groups with progressive cataract formation could be effectively redifferentiated and re-arranged. In the first group, all the peak positions were the same and the peak at 1651 cm-1 assigned to the alpha-helix structure was predominant, but the structural compositions of the beta-sheet and beta-turn changed with progressive cataractogenesis. In the second group, in which cataract formation was more advanced, the peak at 1651 cm-1 assigned to the alpha-helix structure shifted to 1658 cm-1 and a new peak appeared at 1647 cm-1, due to random coil structure; the structural compositions of triple helix significantly decreased but the compositions of the beta-sheet and beta-turn slightly increased. Amides II and III of the IR spectra seemed to be less changed in secondary structures.

CONCLUSIONS

These results suggest that FT-IR spectroscopy with Fourier self-deconvolution and curve-fitting programs can be used as a diagnostic tool for the determination of the cataractous maturity of human lens capsules.

Fourier transform infrared spectral evidences for protein conformational changes in immature cataractous human lens capsules accelerated by myopia and/or systemic hypertension

The possible changes in protein structures of the cataractous human lens capsules of the immature patients with myopia and/or systemic hypertension have been investigated using Fourier transform infrared (FT-IR) microspectroscopy. Second-derivative and deconvolution methods have been applied to obtain the position of the overlapping components of the amide I band and assign them to different secondary structures. Changes in the protein secondary structure and composition of amide I band were estimated quantitatively from Fourier self-deconvolution and curve fitting algorithms. The results indicate that myopia and/or systemic hypertension were found to significantly modify the protein secondary structure of the cataractous human lens capsules to increase the beta-type structure and random coil and decrease the alpha-helix structure. Myopia-induced conformational change in triple helix structure was more pronounced. In conclusion, myopia and/or systemic hypertension seem to modify the conformation of the protein structures in cataractous human lens capsule to change ionic permeation through lens capsule to accelerate the cataract formation of senile patients.

Mitosis-specific negative regulation of epidermal growth factor receptor, triggered by a decrease in ligand binding and dimerization, can be overcome by overexpression of receptor

The function of epidermal growth factor receptor (EGFR) was found to be negatively regulated in M phase in which it showed less phosphotyrosine content and reduced intrinsic kinase activity accompanied by retarded electrophoretic mobility owing to total hyperphosphorylation. Ligand-induced autophosphorylation and downstream signaling of EGFR were tightly suppressed in M phase due to a decrease in ligand binding affinity and the inability of epidermal growth factor (EGF) to induce receptor dimerization. There was no change in the number of surface-exposed EGF receptors between G0/G1 and M phases of the cell cycle. Hyperphosphorylation (due to serine and/or threonine phosphorylation) correlates with the unresponsiveness of cells to EGF-mediated stimulation of tyrosine phosphorylation in cells that express the normal or basal level of EGFR. This M phase-specific negative regulation was overcome by overexpression of EGFR, which was responsive to ligand throughout the cell cycle and revealed ligand-induced signaling in the M phase. These findings indicate that EGFR does not respond to ligand stimulation in M phase and suggest that a negative regulation of ligand-receptor interactions in M phase may control the normal function of receptor tyrosine kinase and that receptor overexpression will disrupt this cell cycle-dependent regulation of receptor tyrosine kinases.