Expression of beta-amyloid precursor protein immunoreactivity in the retina of the rat during normal development and after neonatal optic tract lesion

Immunoreactivity to beta-amyloid precursor protein (APP) was present in the inner plexiform, ganglion cell and optic fibre layers, as well as in blood vessels, at birth in normally developing rat retinas. In the inner plexiform layer immunoreactivity disappeared by postnatal day (P) 14. A small population of ganglion cells was immunoreactive at birth, but none were visible at P7. From P14 onwards, however, there was weak immunoreactivity in ganglion cells again, and strong staining in Müller glia. Retinas affected by neonatal optic tract lesions contained more immunoreactive ganglion cells at P4 than did controls, but by P14 there was a severe loss of ganglion cells. These observations are consistent with APP being involved in retinal differentiation, including maturation of glia and neurones, synaptogenesis and possibly neuronal survival.

Factor structure and age effects with an aphasia test battery in normal Taiwanese adults

This study was designed to explore in a Taiwanese sample the factor structure of an aphasia test battery composed of parts of several standardized aphasia tests. A secondary goal was to assess effects of normal aging on the obtained factors. The sample was 120 healthy Taiwanese adults, ranging in age from 30 to 78 years. Principal-components analysis of the aphasia test battery revealed 5 factors: verbal comprehension, effortful writing, word production, automatized writing, and visuomotor coordination skills. Because the latter 2 factors have common psychological features, they can be combined and reinterpreted as a factor on the mechanics of writing. Further data analysis with factor scores shows that aging unfavorably influences verbal comprehension, effortful writing processing, and word production functions.

Idiopathic hypereosinophilic syndrome with eosinophilic myositis, peripheral neuropathy and central nervous system involvement

Idiopathic hypereosinophilic syndrome (HES) is a rare disorder marked by a sustained overproduction of eosinophils and a predilection for damage to multiple organ systems. Its neurologic involvement ranges from the central to the peripheral nervous system, and can be associated with eosinophilic myositis. We report a 68-year-old woman who had eosinophilia, eosinophilic dermatitis and eosinophilic pneumonia. She also suffered from numbness and weakness of the lower limbs. Because of long-lasting (> 6 mo) eosinophilia (> 1.5 x 10(9)/L) in the peripheral blood and the fact that no other underlying causes of eosinophilia and neurologic involvement could be identified, a diagnosis of idiopathic hypereosinophilic syndrome was made. The muscle biopsy showed infiltration of inflammatory cells, including a few eosinophils (Liu's stain). Magnetic resonance images, motor evoked potentials, somatosensory evoked potentials and nerve conduction velocities also showed abnormalities in the central and peripheral nervous systems. The pathogenesis and treatments of HES are discussed in this report.

Local application of anti-NGF blocks the collateral sprouting in rats following chronic constriction injury of the sciatic nerve

Systemic administration of anti-nerve growth factor (NGF) antibodies can block nociceptive fiber sprouting into denervated adult rat skin. However, the effect of local application of anti-NGF on collateral sprouting in rats caused by chronic constriction injury (CCI) has not been well studied. We investigated the influence of local anti-NGF on collateral sprouting caused by CCI of the rat's sciatic nerve. Using a dye-labeled plasma extravasation technique, we can easily evaluate the extent of collateral sprouting by the clearly defined blue coloration area. Our results showed that local application of anti-NGF either in a high or low dose significantly prevented the spread of collateral sprouting from the saphenous nerve into the sciatic innervation territory. In contrast, distilled water did not show a significant block of the saphenous nerve collateral sprouting. Our study suggests that collateral sprouting is dependent on the local availability of NGF by the nearby intact cutaneous nerve fibers.

Distribution of beta-amyloid precursor and B-cell lymphoma protooncogene proteins in the rat retina after optic nerve transection or vascular lesion

The expression of beta-amyloid precursor protein (APP) and B-cell lymphoma protooncogene protein (Bcl-2) in retinal cells in the rat was studied using immunocytochemistry at different times after intraorbital optic nerve transection or vascular lesion. Three hours to one month after transection of the optic nerve, a significant increase in APP and Bcl-2 immunostaining was observed in retinal Müller glia but not in retinal neurons. In contrast, injury to blood vessels that supply the eye without cutting the optic nerve resulted in a complete loss of APP and Bcl-2 immunostaining in Müller cells and an increase in immunoreactivity in distinct populations of retinal neurons. The overall pattern of APP immunostaining in Müller cells and neurons was essentially the same as that of Bcl-2 under identical experimental conditions. These results suggest that the expression of APP and Bcl-2 in retinal cells is dependent on the nature and severity of injury, and that rapid and common mechanisms are involved in regulating the expression of these molecules.

Identification of naturally occurring dominant negative mutants of thyroid hormone alpha 1 and beta 1 receptors in a human hepatocellular carcinoma cell line

To understand the function of thyroid hormone nuclear receptors (TRs) in human hepatocellular carcinoma cells (HCC), we characterized the hormone binding and transactivational activity of TRs in a HCC cell line, J7. TR alpha 1 (J7-TR alpha 1) and TR beta 1 (J7-TR beta 1) complementary DNAs were cloned from this cell line, and the binding activity to the hormone response elements (TREs) and to the thyroid hormone, 3,3',5-triiodo-L-thyronine (T3) of the expressed TR proteins were evaluated. J7-TR alpha 1 and J7-TR beta 1 bound to TREs similarly as the TRs isolated from other tissues. However, J7-TR alpha 1 did not bind to T3, and J7-TR beta 1 bound to T3 with only about 10% the affinity of the wild-type TR beta 1. Sequencing of the complementary DNAs shows a single Met259Ile mutation in J7-TR alpha 1 and Met334Val in J7-TR beta 1. Using reporters containing TREs, we found that J7-TR alpha 1 and J7-TR beta 1 had virtually lost their transactivational activity. Moreover, these two mutants inhibited the transactivational activity of the wild-type TRs by a dominant negative effect not only on the transfected TRs, but also on endogenous TRs in other two HCC cell lines, SK-Hep-1 and HepG2. The potency of the dominant negative effect of these two mutants inversely correlated with the expression level of endogenous TRs. The present studies identified two novel naturally occurring TR mutants that have potent dominant negative action. The identification of both the alpha and beta dominant negative mutants in J7 made this cell line a useful model system to further understand the molecular mechanism of the dominant negative action of TR mutants.

Vocal cord paralysis as an initial sign of multiple system atrophy in the central nervous system

Multiple system atrophy (MSA) of the central nervous system has been recognized as a rare cause of stridor secondary to vocal cord paralysis. This respiratory problem usually occurs in the later stages of the disease. We report the case of a 53-year-old man who presented with bilateral vocal cord paralysis accompanied by stridor and sleep apnea, which were relieved by a tracheostomy. Two years after the onset of stridor, he developed extrapyramidal and cerebellar signs combined with severe autonomic failure. Magnetic resonance imaging of the brain revealed atrophy of the brainstem and cerebellum. This clinical picture is consistent with the diagnosis of MSA. Vocal cord paralysis preceding any other neurologic and autonomic manifestations has been infrequently described. This case should remind clinicians that MSA should be considered in the differential diagnosis of vocal cord palsy of undetermined origin.

Generation of packaging cell lines for pseudotyped retroviral vectors of the G protein of vesicular stomatitis virus by using a modified tetracycline inducible system

We have previously shown that the G protein of vesicular stomatitis virus (VSV-G) can be incorporated into the virions of retroviruses. Since expression of VSV-G is toxic to most mammalian cells, development of stable VSV-G packaging cell lines requires inducible VSV-G expression. We have modified the tetracycline-inducible system by fusing the ligand binding domain of the estrogen receptor to the carboxy terminus of a tetracycline-regulated transactivator. Using this system, we show that VSV-G expression is tetracycline-dependent and can be modulated by beta-estradiol. Stable packaging cell lines can readily be established and high-titer pseudotyped retroviral vectors can be generated upon induction of VSV-G expression.

Inducible gene expression by retrovirus-mediated transfer of a modified tetracycline-regulated system

The ability to regulate gene expression via exogenous stimuli will facilitate the study of gene functions in mammalian cells. In the present study, we modified the tetracycline-controlled inducible system by the addition of the ligand-binding domain of the estrogen receptor to the carboxy terminus of the tTA transactivator. A single retroviral vector can transduce both the transactivator gene and the gene of interest controlled by the tTA-inducible promoter into mammalian cells. We show that cell lines expressing the transactivator can readily be established and that expression of the gene of interest depends on the removal of tetracycline and the addition of estrogen. By using this system, cell lines with inducible expression of the G protein of vesicular stomatitis virus, a potentially toxic gene product, were established. The combination of a powerful inducible system and retrovirus-mediated gene transfer can not only be used to study gene function but may also be applied in the future to clinical trials in human gene therapy.

A longitudinal study of multimodal evoked potentials in patients following radiotherapy for nasopharyngeal carcinoma

Radiation rhombencephalopathy and radiation myelopathy may occur in patients months or years after radiotherapy for malignancy of the head and neck. We obtained multimodal evoked potentials longitudinally in 26 patients with proven nasopharyngeal carcinoma. Recordings were made before radiotherapy and at 1 week, 3 months, 9 months, 15 months, and 24 months after radiotherapy. All absolute latencies of evoked response before and after radiation were within normal limits. However, the I-III interpeak latencies of brainstem auditory evoked potentials and the onset latencies of motor evoked potentials in the whole group of patients at 15 months after radiation were significantly longer than those before radiotherapy, whereas the latencies at 24 months were not significantly different. The N20 latencies of somatosensory evoked potentials after radiotherapy were significantly prolonged at 3 months of follow-up; the prolongation then became normal. They indicate that a subclinical reversible radiation-induced dysfunction may occur in the auditory, sensory, and motor systems.

Connective tissue grafting for primary closure of extraction sockets treated with an osteopromotive membrane technique: surgical technique and clinical results

This article describes a grafting technique using connective tissue to predictably obtain primary closure of extraction sockets treated with an osteopromotive membrane technique. This technique was used for a total of 24 sites in 22 consecutive patients to regenerate alveolar bone in severely damaged ridges and in conjunction with implants immediately installed into extraction sites. Two sites (8.3%) were complicated by premature membrane exposure that necessitated early removal. In the remaining 22 sites, membranes remained completely covered for a mean period of 23.75 weeks (SD = 8.21 weeks; range = 10 to 38 weeks).

Magnetic resonance images of Tolosa-Hunt syndrome before and after steroid therapy

Tolosa-Hunt syndrome (THS) is characterized by painful ophthalmoplegia due to idiopathic granulomatous inflammation of the cavernous sinus. Steroid therapy dramatically reverses the clinical signs and symptoms of THS. We report a typical case of THS, in which MRI showed a mass lesion in the right cavernous sinus with intermediate signal intensity on T1-weighted images, hypointensity on T2-weighted images and positive gadolinium enhancement. This 24-year-old man had three episodes of painful opthalmoplegia in a period of 9 months. The side of the involved cavernous sinus was different in the first and the second episodes of THS. The symptoms lasted for 1 month and the patient recovered spontaneously from these two episodes. In the third episode, the right pupil was also involved and the light reflex was lost. After steroid therapy, the ocular symptoms improved rapidly within 48 hours and the mass lesion in the right cavernous sinus on MRI was markedly diminished by the 7th day of treatment.

Juvenile-onset of Dejerine-Sottas disease in a Taiwanese woman

Dejerine-Sottas disease is an uncommon hereditary neuropathy which has not been reported in Taiwan. We describe a 57-year-old woman who had slowly progressive weakness in her four limbs since adolescence. None of her close relatives had the disease and no consanguinity was noted. Neurologic examination showed severe weakness and vibratory sensation loss in the four limbs. The tendon reflexes were generally absent. Electrophysiologic studies suggested a systemic myelinopathic process. Light and electron microscopy of the sural nerve biopsy specimens revealed many onion-bulb shapes formed by the Schwann cell processes or basement membranes without any evidence of myelin sheaths around the axons, which are characteristic features of Dejerine-Sottas disease.

Bacterial meningitis in patients with nasopharyngeal carcinoma

Bacterial meningitis was found in 12 patients with nasopharyngeal carcinoma, accounting for 0.65% of the 1850 patients with the tumour diagnosed between 1981 and 1994 in our hospital. In 11 patients, the time-lag between diagnosis of cancer and the appearance of infection ranged from 9 months to 11 years (mean 57 months) whereas in one patient it was only 5 days. Three patients developed mixed bacterial meningitis. Cerebrospinal fluid culture for bacteria was positive in six patients. Three patients (25%) were bacteraemic. Gram-negative bacilli, especially Pseudomonas aeruginosa, were the most common pathogens. Age, sex and histopathology were not risk factors for infection. Conditions predisposing to meningitis included intracranial invasion of the tumor, neutropenia, otitis media, and neurosurgical procedures. All but two patients had intracranial tumour invasion and erosion of the base of the skull. Local spread of micro-organism to the meninges was more important than haematogenous spread. The overall mortality in our patients was 66.7%, much higher than in patients without cancer.

Tuberculous meningitis in patients with nasopharyngeal carcinoma

Mycobacterial infection has been recognized as a complication in patients with malignancy. Tuberculous (TB) meningitis has not been reported in patients with nasopharyngeal carcinoma (NPC); it may have been overlooked or confused with the underlying malignancy or meningitis caused by other microorganisms. We describe the occurrence of culture-proven TB meningitis in 2 NPC patients. The time lag between the diagnosis of NPC and the occurrence of TB meningitis was 4 years in 1 patient and 6 years in the other. In both patients, the diagnosis of TB meningitis was delayed; they were initially treated for bacterial meningitis. Subsequent antituberculous chemotherapy was successful in 1 patient but failed in the other. Recognition of the infection is important for early diagnosis and proper treatment of this potentially fatal condition in patients with NPC.

Solution conformation of a peptide corresponding to residues 151-172 of HIV-1 integrase using NMR and CD spectroscopy

The solution structure of a synthetic peptide corresponding to residues 151-172 of HIV-1 integrase has been determined by NMR and CD spectroscopy. Residues 151-172 of HIV-1 integrase were predicted to be an alpha-helix and to be responsible for the oligomerization of HIV-1 integrase. Two-dimensional 1H NMR and CD studies indicate that this synthetic peptide adopts an amphipathic alpha-helical conformation in TFE-containing solution. However, concentration-dependent CD studies reveal that this peptide motif does not form dimers or oligomers in solution as predicted. These results are in agreement with the crystal structure of the catalytic domain of HIV-1 integrase reported recently.

Kinetic resolution of amino acid esters catalyzed by lipases

Racemic amino acids were resolved by lipase via hydrolysis of their esters. Lipases (Pseudomonas lipase from Amano PS, Rhizopus lipase from Serva, and porcine pancrease lipase from Sigma) could selectively hydrolyze the L-amino acid esters in aqueous solution with high reactivities and selectivities. The effect of the structural changes in the ester moiety on the stereoselectivity of the lipases was also investigated using D,L-homophenylalanine as a model. Procedures were developed for the resolution of natural and unnatural amino acids.

Rimmed, vacuolar distal myopathy in two Taiwanese siblings

Distal myopathy with rimmed vacuoles (DMRV) is a rare disease that has not previously been reported in Taiwan. This paper reports two siblings with DMRV. Each showed a different pattern of disease progression, one being slowly and the other rapidly progressive. Both patients' initial symptoms appeared in early adulthood, manifesting as muscular wasting and weakness of the legs, especially in the distal muscles. Severe generalized involvement of skeletal muscles, with sparing of the facial, extraocular, bulbar, intercostal and diaphragm muscles was recognized in the advanced stage. The striking finding in their muscle biopsy specimens was the presence of "rimmed" vacuoles. Magnetic resonance imaging showed more severe involvement of the anterior compartment muscles of the lower legs. DMRV is thought to be inherited as an autosomal recessive trait and is distinguishable from other types of distal myopathy on the basis of clinical and pathologic findings. The literature on the subject is reviewed with emphasis on the differences between distal myopathic syndromes.

Increased invasive activity of human hepatocellular carcinoma cells is associated with an overexpression of thyroid hormone beta 1 nuclear receptor and low expression of the anti-metastatic nm23 gene

To understand the role of thyroid hormone in metastasis, we studied the expression of the anti-metastatic nm23 gene in eight human hepatocellular carcinoma (HCC) cell lines. These cells differentially expressed the anti-metastatic nm23 gene. A low level of nm23 proteins was found to have a high in vitro invasive activity which correlated closely with an overexpression of the thyroid hormone beta 1 nuclear receptor (h-TR beta 1). Concurrent with the down-regulation of h-TR beta 1, the invasive activity of HCC cells was suppressed by the thyroid hormone, 3,3',5-triiodo-L-thyronine (T3). These results indicate that the invasive activity of HCC cells was regulated by T3, suggesting that T3 could be involved in modulating the functions of nm23.

MRI/myelographic localization of fistulous tract in spinal dural arteriovenous malformations prior to arteriography

OBJECTIVE

Our goal was to use currently available imaging methods to localize the fistulous tract of spinal dural arteriovenous malformations (SDAVMs) prior to arteriography.

MATERIALS AND METHODS

Two middle-aged men showed MR findings indicative of a SDAVM. In the first patient coronal T2-weighted (T2W) imaging identified the engorged draining radiculospinal vein and traced it back to the intervertebral foramen site where the "nidus" was located. Then, axial T2W imaging was performed at the level of the involved intervertebral foramen. In the second patient MRI failed to demonstrate the nidus; myelography was carried out and showed the course of the abnormal intraspinal vein.

RESULTS

Successful MR/myelographic demonstration of the nidus (Case 1) or the abnormal intraspinal vein (Case 2) simplified and abbreviated the later studies.

CONCLUSION

With MRI and/or myelography we were able to localize the site of the fistulous tract in the two cases of SDAVM prior to spinal arteriography.

Alkaline protease catalysis of a secondary amine to form a peptide bond

Procedures for peptide bond formation using esters of L-amino acids as the acyl donor and secondary amines such as derivatives of D- or L-proline, or pyroglutamic acid as the nucleophile in anhydrous 2-methyl-2-propanol catalyzed by alcalase or subtilisin Carlsberg have been developed. Kinetic studies have shown that all secondary amines tested had catalytic efficiencies (kcat/km) in the range 84-423 min-1 M-1. Both enzymes have identical catalytic properties. The selectivity of the enzyme-catalyzed reaction in 2-methyl-2-propanol shows that at the s-1 subsite of the enzyme only L-amino acids are substrates as acyl donors, and at the s-1' subsite both D- and L-amino acids are substrates. Optimal conditions for preparing precursors of the renin inhibitors Z-Ala-Pro-OBzl, Z-Lys(Z)-Pro-OBzl and Z-Lys(TFA)-Pro-OBzl were studied.

Concurrent trigeminal, abducens, and facial nerve palsies presenting as false localizing signs: case report

Multiple cranial nerve dysfunction presenting as false localizing signs is rare. We report a 20-year-old woman who had concurrent trigeminal sensory disturbance, abducens, and peripheral facial nerve palsies in association with a contralateral acoustic neuroma. After surgery, the trigeminal nerve disturbance and the abducens nerve palsy completely recovered, but the peripheral facial nerve palsy persisted. The nature of tumor, the presence of brain stem distortion, the anatomic variation of posterior fossa, and the relationships of cranial nerves and nearby blood vessels, which are factors influencing the occurrence of false localizing, are briefly discussed.

Long-term expression of the biologically active growth hormone in genetically modified fibroblasts after implantation into a hypophysectomized rat

We employed the hypophysectomized rats as an animal model to explore the feasibility of using genetically engineered fibroblast cells for growth hormone gene therapy. An internal ribosome entry site (IRES)-directed bicistronic retroviral vector, PSN, which contained a porcine growth hormone (pGH) cDNA at the first cistron and a Neo(r) gene at the second cistron was used to infect primary rat embryo fibroblast (REF) cells. The infected cells (5 x 10(6) cells/rat) were injected directly into the peritoneum of syngeneic hypophysectomized rats. We demonstrate that the implanted PSN-infected REF cells could secrete biologically active pGH in vivo, leading to significant growth of the tibia at day 15 and day 57 post-implantation. We also treated the PSN-infected REF cells with collagen to form a tissue-like structure. The skin-like discs were grafted underneath the skin on the back of rats and cells were retrieved at different times. Using two criteria, semiquantitative reverse transcription-polymerase chain reaction on the pGH RNA extracted from the explants and G418 resistance conferred from the explanted cells, we demonstrate that pGH was expressed in the implanted fibroblasts up to 70 days. Despite the fact that the total pGH RNA level was reduced in the explants of long-time post-implantation, which was probably due to the reduction of transduced cells retained in the explants, the specific efficiencies of pGH RNA expression from these explants were maintained as high as the primary PSN-infected REF prior implantation. These results suggest that fibroblast cells are capable of expressing the foreign genes persistently in vivo.

Conformational studies of a synthetic cyclic decapeptide fragment of rat transforming growth factor-alpha

The solution conformation of a synthetic cyclic decapeptide [with sequence mimicking the third disulfide loop of rat transforming growth factor-alpha (rTGF-alpha)] in deuterated dimethyl sulfoxide was studied by 2D NMR. The determination of solution structures was based on NOE interproton distances, using a combination of distance geometry and simulated annealing protocols. The convergence of the selected structures was evident from the small atomic pairwise root-mean-square deviation values among them. Good agreement was noted between the experimental and simulated NOESY spectra, thereby reflecting the accuracy of the calculated solution structures. Analysis of the structures indicates that the residues Tyr5 and Arg9 exhibit similar side chain orientation as that in the corresponding disulfide loop of human transforming growth factor-alpha.