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.

Brain-derived neurotrophic factor rapidly enhances phosphorylation of the postsynaptic N-methyl-D-aspartate receptor subunit 1

Although neurotrophins have traditionally been regarded as neuronal survival factors, recent work has suggested a role for these factors in synaptic plasticity. In particular, brain-derived neurotrophic factor (BDNF) rapidly enhances synaptic transmission in hippocampal neurons through trkB receptor stimulation and postsynaptic phosphorylation mechanisms. Activation of trkB also modulates hippocampal long-term potentiation, in which postsynaptic N-methyl-D-aspartate glutamate receptors play a key role. However, the final common pathway through which BDNF increases postsynaptic responsiveness is unknown. We now report that BDNF, within 5 min of exposure, elicits a dose-dependent increase in phosphorylation of the N-methyl-D-aspartate receptor subunit 1. This acute effect occurred in hippocampal synaptoneurosomes, which contain pre- and postsynaptic elements, and in isolated hippocampal postsynaptic densities. Nerve growth factor, in contrast, caused no enhancement of phosphorylation. These results suggest a potential mechanism for trophin-induced potentiation of synaptic transmission.

A phase I feasibility and pharmacokinetic study of intrapleural paclitaxel in patients with malignant pleural effusions

To evaluate the feasibility and pharmacology of intrapleural (IP(L)) administration of paclitaxel, 18 patients with malignant pleural effusions were entered onto a phase I clinical study, 13 were caused by lung cancer. Following an effusion drainage rate of less than 100 ml/24 h and full expansion of the lung, patients were treated with a single instillation of pacilitaxel administered IP(L) in 500 ml of normal saline and retained for a maximum of 96h when tolerated. No systemic chemotherapy or ipsilateral thoracic irradiation was given for 4 weeks before and after the IP(L) treatment. The starting dose was 82.5 mg/m2 with the dose escalation schedule of 125, 175, 225 and 300 mg/m2. There were minimal local or systemic toxicities, such as local chest pain or myelosuppression, even when the paclitaxel dose reached 225 mg/m2. The pharmacological advantages of the IP(L) administration of paclitaxel were demonstrated by the mean exposure of the pleural cavity (area under the concentration time curve) to paclitaxel after IP(L) delivery exceeding that of the plasma by approximately 370-fold (range 55-684) and by the extraordinarily slow IP(L) clearance of paclitaxel (mean +/- SE 0.49 +/- 0.07 l/m2/day; range 0.08-1.16 l/m2/day) with significant concentrations of paclitaxel persisting within the cavity for more than 48-96 h after a single IP(L) instillation. In patients with detectable plasma paclitaxel levels, the plasma levels achieved exceed the minimal concentrations that are required to induce cytotoxic effects in vitro. Four patients had progressive dyspnea during IP(L) retention of paclitaxel solution because of treatment failure and needed drainage of effusion. One of these patients who was at the dose level of 225 mg/m2 originally had severely chronic obstructive lung disease, developed acute respiratory failure, refused mechanical ventilation support and succumbed to respiratory failure. No further patients were included after this event. Antitumor effect was shown by four of the 15 evaluable patients having no recurrence of effusion on chest radiograph at 1 month. Most of these responders had a good performance status, normal pretreatment pleural pH and/or glucose compared with the non-responders. We conclude that paclitaxel at a dose level of 175 or 225 mg/m2 is feasible for use intrapleurally. It could be considered for incorporation into treatment programs for patients with less advanced thoracic tumors with carcinomatous pleuritis or with IP(L) tumors following surgical debulking.

Induction of superoxide dismutase and catalase activity in different rat tissues and protection from UVB irradiation after topical application of Ginkgo biloba extracts

Ginkgo biloba extract (GBE) prepared from the leaves of Ginkgo biloba with 50% diluted alcohol was found to locally induce superoxide dismutase (SOD) and catalase (CAT) enzyme activity in epidermis after topical application, and also to systemically increase the activity of both enzymes in the liver, heart and kidney of Sprague Dawley rats. Skin pretreated with 50% diluted alcohol-extracted liquid formulation was protected from exacerbation of UVB damage. Changes in the lipid structure of the skin of rats determined by ATR/FT-IR spectroscopy demonstrated penetration of active components from GBE dosage formulations.

The choroidal blood flow response after flicker stimulation in chicks

Form-deprivation myopia (FDM) can be prevented by exposing the animal to stroboscopic illumination (10 Hz). Flicker illumination is known to stimulate the release of dopamine (DA) from the retina. We hypothesize that DA was released and diffused into the choroid. To prove this hypothesis, we decided to undertake an investigation in chicks and measure choroidal blood flow (ChBF) during stimulation of the ocular fundus with diffuse flicker. White Leghorn chicks (2 weeks old) were used for this study. Different flash stimulations (5 Hz approximately 50 Hz) were given for 3 minutes, then ChBF was recorded with the PeriFlux flowmeter simultaneously and continuously for 5 minutes. Some birds are recorded up to 120 minutes to find out any late-onset effect. The ChBF was increased after flicker stimulation. The difference was statistically significant in 10 Hz, 20 Hz, and 30 Hz. The ChBF can maintain 20% higher for 60 minutes. Therefore, flicker illumination preventing FDM may be induced by the hyperactivity of ganglion cells, then stimulates the release of DA from the retina and suppresses the development of myopia.

Mechanism of the natriuretic action of gamma-melanocyte-stimulating hormone

To explore the mechanism underlying the natriuretic effect of gamma-melanocyte-stimulating hormone (gamma-MSH), we infused the peptide intravenously at 200 pmol/min into anesthetized rats. gamma-MSH led to a progressive increase in urinary sodium excretion (UNaV), whereas continuous infusion of the vehicle did not affect UNaV. Plasma immunoreactive gamma-MSH was nine times greater at 120 min after the start of the infusion than in vehicle-infused rats. Plasma atrial natriuretic peptide (ANP) concentration also increased as a consequence of the gamma-MSH infusion, and a strong correlation existed between the concentrations of the two peptides (n = 17, r = 0.81, P < 0.001). Urinary excretion of guanosine 3',5'-cyclic monophosphate and adenosine 3',5'-cyclic monophosphate increased as a result of the infusion. Antiserum to rat ANP blunted the natriuresis only slightly, suggesting that the increase in plasma ANP concentration was not a critical element in gamma-MSH natriuresis. gamma-MSH had no effect on ANP release from isolated rat right atrial strips superfused in vitro. Infusion of gamma-MSH (500 fmol/min) directly into one renal artery led to an ipsilateral natriuresis without change in UNaV from the contralateral kidney. Prior denervation of the infused kidney prevented the natriuresis resulting from intrarenal infusion. Intrarenal infusion of ANP (800 fmol/min) also produced ipsilateral natriuresis, which, however, was not affected by renal denervation. These studies confirm that the natriuretic action of gamma-MSH occurs primarily by an interaction with the renal nerves. Intravenous infusion of the peptide sufficient to produce a supraphysiological plasma gamma-MSH concentration also results in an increase in plasma ANP concentration; however, this increase at best plays only a minor role in the natriuresis following intravenous gamma-MSH infusion.

Characterization of Orientia tsutsugamushi isolated in Taiwan by immunofluorescence and restriction fragment length polymorphism analyses

A total of 10 strains of Orientia tsutsugamushi were isolated from field rodents and chiggers in Taiwan, and characterized by immunofluorescence analysis with monoclonal antibodies and by restriction fragment length polymorphism analysis of the 56-kilodalton (kDa) protein gene. The isolates were divided into two groups consisting of 1 and 9 strains which showed some relation to Gilliam and Karp type strains, respectively. However, all these isolates possessed characteristics distinct not only from those of known prototype strains including Gilliam and Karp but also from all isolates from Japan. These findings suggest the existence of a large number of immunotypic and genotypic variants among the strains of O. tsutsugamushi, and the distribution of distinguishable strains in each area to which this species is endemic.

[Spatial and temporally expressed proteins during Drosophila oogenesis as revealed by monoclonal antibodies]

By use of hybridoma technique, we have prepared 6 monoclonal antibodies. As shown by antibody labeling of whole mount ovary, four of them recognized, respectively, the antigens which were spatial-temporally expressed during oogenesis. The B 2 antigens appeared very early in the germarium and were expressed mainly by cystocyte and nurse cells. Later, they were all transported and localized in the posterior of oocyte, F 9 antigens followed and were also transported and localized in the posterior of oocyte in the stage 7-8. Then, E 8 antigens appeared and mainly localized on the membrane of oocyte in the stage 9-10. C 3 antigens were expressed much later, at about stage 14. They localized like two caps in the perivitelline fluid at both ends of matured egg. Such specific expression and distribution pattern of all these antigens suggest their possible roles during oogenesis.

Surgical treatment of complete acromioclavicular separations

A retrospective study of fifty-two patients (48 cases followed up), with Allman-Tossy grade III acromioclavicular separations, who were treated with coracoclavicular reconstruction by Mersilene prosthetic substitute (Mersilene tape with polyester suture, 5 mm wide, 30 cm, Ethicon), was carried out. The average follow up was 38 months, with the longest being 10 years, and the shortest being 8 months. The average age of the patients was 32 years, with a range from 20 to 62 years. Two groups were divided by age. Although the younger age group showed better results than the elder one in pain, range of motion and return to previous occupation or sports, the overall outcome was satisfactory in 41 of 48 (86%) followed patients. For the grade III acromioclavicular separation patients, surgical reconstruction with Mersilene looping provides a reliable result including use of the arm for sports or repetitive work.

Comparisons of geniposidic acid and geniposide on antitumor and radioprotection after sublethal irradiation

The antitumor effects of two iridoid compounds, geniposidic acid (GA) and geniposide (GP), were investigated in mice along with their possible effects on radioprotection after sublethal X-irradiation. Decreases in the growth of the implanted tumor by ascitic cells were a result of intraperitoneal administration of GA and GP at high concentrated levels. This result was achieved by exerting the levels of dosage in a dose-dependent manner. Except on the 12th day after treatment by the dosage of 500 mg/kg, reduced radiation effects of mice treated with the drugs in the 30 min preirradiated period by GA and GP on peripheral leukocytes were not observed significantly by the sublethal whole-body X-irradiation. And except on the 7th day after treatment, when these two compounds were administered i.p. to mice 30 min before 4 Gy irradiation, neither GA nor GP enhanced significantly the postirradiation responses of splenic blastogenesis by PHA. In addition, GA might be a more potent tumor growth inhibitor than GP when combined with the X-irradiation, though there was no significant synergetic effect on their combined antitumor activity. The preliminary results of GA and GP on hematological and blastogenic observations in this study suggested that they may very well, partially, play a role in an effective anticancer product with the ability to decrease undesirable radiation damage to the hematologic tissue after high dose irradiation.

The single positive T cells found in CD3-zeta/eta-/- mice overtly react with self-major histocompatibility complex molecules upon restoration of normal surface density of T cell receptor-CD3 complex

CD3-zeta/eta-deficient mice have small thymuses containing cells that show a profound reduction in the surface levels of T cell receptors and terminate their differentiation at the CD4+CD8+ stage. Rather unexpectedly, CD3- or very low single positive T cells accumulate over time in the spleen and lymph nodes of CD3-zeta/eta-deficient mice after a process dependent on MHC expression. Fusion of these peripheral T cells with a CD3-zeta-positive derivative of the BW5147 TCR-alpha-/beta- thymoma resulted in hybridomas that do express an heterogeneous set of T cell receptor alpha/beta dimers at their surface and at density comparable to those found in hybridomas derived from wild-type peripheral T cells. We have investigated the specificities of these T cell receptors using spleen cells from congenic and mutant mouse strains, and showed that the majority of them readily recognized self-MHC class I or class II molecules. These results demonstrate that by increasing the density and/or output of the T cell receptors expressed in peripheral T cells, one can confer them with the capacity to respond to normal density of self-MHC molecules.

Possible mechanism of exacerbating cataract formation in cataractous human lens capsules induced by systemic hypertension or glaucoma

To clarify the role of the lens capsule in cataract formation, changes in the protein conformational structure of immature cataractous lens capsules from patients with systemic hypertension or glaucoma have been investigated, as compared to normal lens capsules. The protein secondary structure and composition of these capsular samples were determined using Fourier transform infrared microspectroscopy with second-derivative, deconvolution and curve-fitting methods. We found that the composition of both random coil and beta-type (beta-sheet and beta-turn) structures in the immature cataractous human lens capsules was increasingly induced by systemic hypertension or glaucoma, but alpha-helix content clearly decreased, leading to the alteration of protein conformational structures in lens capsules. A possible pathway of cataract formation exacerbated by systemic hypertension or glaucoma is discussed. According to the results, we propose that systemic hypertension or glaucoma induce changes in the protein conformational structures of the lens capsule, then cause alteration of membrane transport and permeability for ions, and finally increase intraocular pressure, resulting in the exacerbation of cataract formation. The effect on the conformational structure of cataractous human lens capsules is more pronounced for systemic hypertension than for glaucoma. The present study implies that systemic hypertension or glaucoma can exacerbate cataract formation in senile patients by modifying the protein secondary structures in the lens capsule.

Functional trkB neurotrophin receptors are intrinsic components of the adult brain postsynaptic density

Neurotrophins have long been thought to act as target-derived factors that regulate the survival and differentiation of afferent neurons. Recently, brain-derived neurotrophic factor (BDNF) was shown to elicit rapid increases in synaptic activity of cultured hippocampal neurons by enhancing responsiveness to excitatory input. These findings suggest a postsynaptic localization of neurotrophin receptors. In this study, we examined the expression of trkB, a high-affinity receptor for BDNF, in the postsynaptic density (PSD), a proteinaceous specialization of the postsynaptic membrane. Western blot analyses with antibodies to trkB revealed localization to the PSD in adult rat cerebral cortex and hippocampus. Only the full-length, active form of trkB was detected in PSD samples. BDNF treatment of the adult cortical PSD resulted in a 5-fold increase in trkB autophosphorylation, supporting the contention that the PSD contains functional trkB. Truncated trkB, which does not contain the tyrosine kinase signaling domain, though present in membrane fractions, was undetectable in the PSD. The presence of trkB in the PSD is consistent with a role for neurotrophins in the regulation of synaptic activity via direct postsynaptic mechanisms.

Progressive changes in secondary conformation and composition of the senile cataractous human lens capsules

The lens capsules of senile cataractous patients were differentiated into three progressive grades of immature (I, II and III) and two progressive grades of mature (I' and II') groups using Fourier transform infrared (FT-IR) microspectroscopy with Fourier self-deconvolution and curve-fitting algorithms, according to the changes in IR peak position and its structural composition. The secondary conformation of both immature-II and mature-I' cataractous human lens capsules was found to change significantly when enhancing the beta-sheet structure but simultaneously decreasing the beta-turn structures, as compared with the composition of normal human and immature-I cataractous lens capsules. The increase in beta-sheet structural proportion might possibly be attributable to the age-related cataractogenesis. We also found that the IR peak at 1651 cm-1 assigned to a-helix shifted to 1647 cm-1 that corresponded to disordered structure, but the IR peak at 1662 cm-1 due to beta-turn structure disappeared and another new IR peak assigned to alpha-helix structure appeared at 1656 cm-1, for both immature-III and mature-II' cataractous lens capsules. It increased the compositions of beta-sheet and disorder structures and simultaneously decreased the triple helix and beta-turn structures, but maintained the same level in alpha-helix structure. This suggests that FT-IR microspectroscopy can act as a potential tool to exactly differentiate the maturity of senile cataractous human lens capsules according to the changes in IR peak position and compositions in amide I band.

The conformational properties of the antineoplastic ether lipid 1-thiohexadecyl-2-O-methyl-S-glycero-3-phosphocholine

Thio analogs of platelet activating factor (PAF) are of great interest because they exhibit antineoplastic properties both in vitro and in vivo. In contrast to most known anticancer agents, these lipids appear not to act through the synthesis and function of DNA and, therefore, offer a new avenue of approaching cancer chemotherapy. We have examined the conformational properties of 1-thiohexadecyl-2-O-methyl-S-glycero-3-phosphocholine (ET-S-16-OCH3) in organic solvents and in micelles. The conformational analysis was based on a combination of 1D, 2D NMR spectroscopy and molecular graphics. 1H and 13C spin lattice relaxation time (T1) experiments were also performed to study the dynamic properties of this molecule. The picture emerging from these studies is as follows. The alkyl chain of ET-S-16-OCH3 is the most mobile part of the molecule both in CDCl3/CD3OD and in micelles and exists as a mixture of interconverting conformers including an extended all trans and several low energy conformers with one or more gauche segments. This creates a twisting of the chain and facilitates a spatial communication between the alkyl chain and the glycerol backbone as well as between the alkyl chain and the headgroup. The methylene groups of the thioglycerol backbone and the headgroup are the least mobile while the methine group of the thioglycerol backbone appears to have an intermediate mobility. The conformation of the thioether lipid in the two media may be of relevance during its interaction with its site of action, the cellular membrane. Such a conformation may also play an important role in determining the selectivity of this interaction with different cell membranes.

Prenatal diagnosis of asphyxiating thoracic dysplasia (Jeune syndrome)

Asphyxiating thoracic dysplasia (ATD), or Jeune syndrome, is an uncommon autosomal recessive skeletal disorder characterized by a small thorax, varying degrees of rhizomelic brachymelia, polydactyly, pelvic abnormalities, and renal anomalies. We describe prenatal sonographic examinations in the third trimester of a fetus with abnormal small thorax, short limbs, polyhydramnios, and absence of fetal respiratory movements. At 36 weeks gestation, the fetal biparietal diameter was 93 mm, compatible with 37 weeks; the long-bone lengths measured < 5th percentile; the thoracic circumference (TC) measured 230 mm (< 5th percentile); the abdominal circumference (AC) measured 286 mm (25th percentile), and the TC/AC ratio was 0.80 (lower limit of normal). Our case shows that, although a discrepancy between gestational age and TC is prominent, TC/AC ratio may reach lower limit of normal in cases of fetal ATD, when fetal growth is compromised.