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Biomedical subjects

C Pu

Publications and source records attributed to C Pu.

At least 19 recordsLinked to original sources
PubMed2001

[Microvascular decompression for hemifacial spasm: experience of 215 cases].

OBJECTIVE: To investigate the relationship between pre-operational etiological diagnosis of medically intractable hemifacial spasm (HFS) and patterns of offending vessels and the curative effect of microvascular decompression (MVD). METHODS: Two hundred and fifteen patients with medically intractable HFS underwent MVD under general anesthesia. Pre-operative MRI examination was made for all cases to exclude space occupying lesion and magnetic imaging tomographic angiography (MRTA) was conducted for 145 cases of them instead of routine MRI. RESULTS: Routine MRI failed to provide information about offending vessels except for ruling out mass lesions whereas MRTA revealed the offending vessels with a positive rate of 82.8%, thus helping make correct diagnosis and operation decision. Follow-up of more than two years showed that the surgical intervention achieved a high relief rate of 91.2% without major complication, and with a low recurrence rate of only 3.5% after averaging more than two years' follow-up. CONCLUSION: Pre-operative MRTA can replace conventional MRI as a best approach for pre-operational etiological diagnosis of facial spasm. It helps perceive the offending vessels before operation. Skilled microsurgical technique along with correct recognition and mobilization of offending vessels are a must to assure MVD a high efficacious and low risk treatment of choice for HFS patients.

Adult↗
PubMed2001

[Research on the dynamic variation and elimination of nitrite content in sauerkraut during pickling].

To investigate the dynamic variation and elimination of nitrite content in pickles and sauerkraut during pickling, green tuber growing in Fuling was selected to make semi-manufactured mustard according to the process technology. Green tuber, cabbage and cauliflower were selected as raw materials to make sauerkraut in family way. The nitrite content in pickles and sauerkraut was determined by spectrophotometry with 1-Amino-2-(a-naphthy lamine) ethoine dihydrochloride. The nitrite content in mustard was 258.8 mg/kg when 6% salt was used and pickling for 8 days; the nitrite content was 235.9 mg/kg when 15% salt was used and pickling for 15 days. There was no nitrite in mustard when pickling for 35 days. The nitrite content in the sauerkraut was 258.7 mg/kg when pickling for 6 days and no nitrite was found after 20 days. The higher nitrite content in pickle and sauerkraut could be eliminated by water. The elimination ratio was 91% for leafy sauerkraut and semi-manufactured cut mustard and only 72% for whole mustard. It was concluded that pickles and sauerkraut that pickled for enough time (for leafy vegetable more than 20 days, for tuber more than 35 days) had no harm for people to eat, The higher nitrite content in pickles and sauerkrauts could be reduced by 91% with water for several times.

Food Preservation↗
PubMed2000

Time-course of methamphetamine-induced neurotoxicity in rat caudate-putamen after single-dose treatment.

The time-course of monoamine and tyrosine hydroxylase depletion after single-dose administration of D-methamphetamine (40 mg/kg s.c.) was investigated in caudate-putamen of male Sprague-Dawley rats. Times evaluated were 6, 12, 48, 72 and 240 h following treatment. Tyrosine hydroxylase was significantly reduced by 29, 60, 66, 76 and 76% of control at each of the respective post-treatment time intervals. Dopamine was not reduced 6 h following treatment. Dopamine was significantly reduced by 53, 57, 68 and 74% 12, 48, 72 and 240 h post-treatment, respectively. Reductions in caudate-putamen serotonin began earlier and were ultimately larger than for dopamine, with significant reductions of 28, 33 55, 74 and 81% at each of the respective post-treatment intervals. Confirmation of neurotoxicity was provided by measurement of glial fibrillary acidic protein (GFAP) 240 h post-treatment. GFAP was increased at this time interval by 150% above control. Methamphetamine-induced hyperthermia during the 6 h immediately after treatment was comparable among the groups of animals used for analyses at each time interval. The results demonstrate that methamphetamine-induced monoamine reductions in the caudate-putamen occur rapidly, peak at 75-80% below controls, and last for at least 10 days after a single dose. These effects are as large or larger than those reported after the commonly used 10 mg/kgx4 dose treatment regimen administered at 2-h intervals and provides an alternate model for the investigation of methamphetamine-induced neurotoxicity.

Animals↗
PubMed1999

[Extensive transbasal approach for removal of tumours in the nasal, sphenoid and clival regions].

OBJECTIVE: To improve operative results of removal of the tumors in midline cranial base and the reconstruction of defect at frontal base through modification of the operative approach and techniques. METHODS: Extensive transbasal approach was used in 15 patients with tumours in the nasal, sphenoid and clival regions. RESULTS: The tumor was removed in 10 patients, near totally removed in 4 and partial removed in 1. The operative results of all patients were excellent except an elderly patient with mild operative morbidity. CONCLUSIONS: The procedure we used expand the operative indications for the tumors situated at the midline cranial base and improve the operative results. The procedure has advantages such as wide operative space, reliable reconstruction of the frontal base, and no severe complications.

Adult↗
PubMed1998

A single dose model of methamphetamine-induced neurotoxicity in rats: effects on neostriatal monoamines and glial fibrillary acidic protein.

The neurotoxic effects of a single administration of methamphetamine (MA) were studied under conditions conducive to MA-induced hyperthermia. After a single dose of MA (10, 20, 30, or 40 mg/kg, s. c.) or saline (3 ml/kg) to Sprague-Dawley CD rats, rectal temperatures were monitored for 9 h in a room with an ambient temperature of 22.0+/-0.5 degrees C. MA induced significant dose-dependent hyperthermia, however, no significant increase in mortality occurred. Neostriatal DA, 5-HT, TH, and GFAP were assayed 3 days following treatment. MA induced dose-dependent reductions of DA, 5-HT and TH, and increased GFAP. For DA, at doses of 20, 30, or 40 mg/kg the reductions were to 71%, 49%, and 29%, and for 5-HT were to 73%, 44%, and 19% of control values. No reductions were seen after the 10 mg/kg dose. Semiquantitative analysis Western blots of TH and GFAP demonstrated that TH was reduced to 52%, 75%, and 28%, and GFAP was increased to 125%, 134%, and 149% of control values at MA doses of 20, 30, or 40 mg/kg, respectively. No significant changes in TH or GFAP were seen at the 10 mg/kg MA dose. These results demonstrate that a single-dose of MA can be as effective as the widely used four-dose every 2 h regimen. Moreover, mortality can be minimized by monitoring core body temperature and preventing MA-induced hyperthermia from exceeding 41.5 degrees C.

Animals↗
PubMed1997

Methamphetamine selectively damages dopaminergic innervation to the nucleus accumbens core while sparing the shell.

Dopaminergic innervation to the nucleus accumbens was investigated following a neurotoxic regimen of methamphetamine (MA) treatment. Four 10 mg/kg doses of MA were administered s.c. to male Sprague-Dawley rats with a 2 h interval between doses. Rectal temperatures were monitored for the induction of MA-induced hyperthermia. Three days or 2 weeks after MA treatment the animals were sacrificed by transcardial perfusion and processed for tyrosine hydroxylase (TH-IR) and glial fibrillary acidic protein immunoreactivity (GFAP-IR). MA treatment produced a severe loss of TH-IR throughout the striatum, including the nucleus accumbens. However, within the nucleus accumbens, there was substantial sparing of TH-IR in the shell, while in the core immunoreactivity was almost entirely lost. Furthermore, astrogliosis, as demonstrated by GFAP-IR, was prevalent in the core but present only in sparse patches in the medial and lateral shell. Thus, dopaminergic innervation to the nucleus accumbens core undergoes degeneration following MA treatment, while innervation to the shell is resistant to the neurodegenerative effects of MA.

Animals↗
PubMed1997

Code generation through annotation of macromolecular structure data.

The maintenance of software which uses a rapidly evolving data annotation scheme is time consuming and expensive. At the same time without current software the annotation scheme itself becomes limited and is less likely to be widely adopted. A solution to this problem has been developed for the macromolecular Crystallographic Information File (mmCIF) annotation scheme. The approach could be generalized for a variety of annotation schemes used or proposed for molecular biology data. mmCIF provides a highly structured and complete annotation for describing NMR and X-ray crystallographic data and the resulting macromolecular structures. This annotation is maintained in the mmCIF dictionary which currently contains over 3,200 terms. A major challenge is to maintain code for converting between mmCIF and Protein Data Bank (PDB) annotations while both continue to evolve. The solution has been to define a simple domain specific language (DSL) which is added to the extensive annotation already found in the mmCIF dictionary. The DSL calls specific mapping modules for each category of data item in the mmCIF dictionary. Adding or changing the mapping between PDB and mmCIF items of data is straightforward since data categories (and hence mapping modules) correspond to elements of macromolecular structure familiar to the experimentalist. Each time a change is made to the macromolecular annotation the appropriate change is made to the easily located and modifiable mapping modules. A code generator is then called which reads the mapping modules and creates a new executable for performing the data conversion. In this way code is easily kept current by individuals with limited programming skill, but who have an understanding of macromolecular structure and details of the annotation scheme. Most important, the conversion process becomes part of the global dictionary and is not open to a variety of interpretations by different research groups writing code based on dictionary contents. Details of the DSL and code generator are provided.

Crystallography, X-Ray↗
PubMed1996

Effect of methamphetamine on glutamate-positive neurons in the adult and developing rat somatosensory cortex.

The neurotoxic effects of methamphetamine (MA) on dopaminergic and serotonergic terminals have been well-documented. Another neurotoxic effect of MA is neuronal degeneration in the somatosensory cortex, as seen by silver staining. The neurochemical characteristics of these degenerating neurons are unknown. Using glutamate and glial fibrillary acid protein (GFAP) immunohistochemistry, it was found that MA exposure in adult rats (10 mg/kg given 4 times intraperotoneally (i.p.) at 2-h intervals) causes localized depletion of glutamate-positive neurons and astrogliosis in the somatosensory cortex 3 days following treatment. The affected region covered the middle one-third portion from the longitudinal fissure to the rhinal sulcus and was predominately seen in layers II-III of the cortex. This pattern of depletion is consistent with that demonstrated previously with silver staining following MA, d-amphetamine, and 3,4-methylenedioxymethamphetmine (MDMA) exposures. Comparable efforts were not found in developing animals at ages previously shown to also be resistant to MA-induced effects on dopaminergic terminals (age 20 and 40 days). Results suggest that MA exposure induces degeneration of glutamatergic neurons in the somatosensory cortex of adult rats.

Animals↗
PubMed1996

alpha-Phenyl-N-tert-butyl nitrone attenuates methamphetamine-induced depletion of striatal dopamine without altering hyperthermia.

Methamphetamine (MA) administration to adult rats (4 x 10 mg/kg s.c.) induces neurotoxicity predominately characterized by a persistent reduction of neostriatal dopamine (DA) content. Hyperthermia following MA administration potentiates the resulting DA depletion. DA-derived free radicals are postulated to be a mechanism through which MA-induced neurotoxicity is produced. The spin trapping agent PBN reacts with free radicals to form nitroxyl adducts, thereby preventing damaging free radical reactions with cellular substrates. MA with saline pretreatment (Sal-MA) reduced neostriatal DA by 55% (P < 0.01 vs. Sal-Sal). MA with PBN pretreatment (PBN-MA) at 36 or 60 mg/kg reduced neostriatal DA by 36 and 22%, respectively (P < 0.05 and P < 0.01 vs Sal-MA) indicating partial protection. PBN pretreatment did not alter MA-induced hyperthermia. Thus, PBN does not attenuate MA-induced neurotoxicity by reducing MA-induced hyperthermia. These results support a role for free radicals in the generation of MA-induced dopaminergic neurotoxicity.

Animals↗
PubMed1995

Protective effects of MK-801 on methamphetamine-induced depletion of dopaminergic and serotonergic terminals and striatal astrocytic response: an immunohistochemical study.

It has been shown previously that methamphetamine induces dopaminergic nerve terminal degeneration, serotonin depletion and striatal reactive astrogliosis, and that the noncompetitive N-methyl-D-aspartate (NMDA) antagonist MK-801 can block methamphetamine (MA)-induced depletion of dopamine and serotonin and reduction in activity of their synthetic enzymes. In this study, immunohistochemistry was used to evaluate the effect of MK-801 on methamphetamine-induced neuropathological alterations of dopaminergic and serotonergic terminals and striatal astrocytic responses. Adult male rats were treated with methamphetamine (4 injections of 10 mg/kg at 2 hour intervals) in conjunction with MK-801 which was administered 15 min before each methamphetamine administration at doses of 1 mg/kg or 2 mg/kg. Brains were examined three days following treatment. MK-801 administration prevented methamphetamine-induced depletion of 5-hydroxytryptophan (5-HT) terminals in the forebrain and depletion of tyrosine hydroxylase-positive dopaminergic terminals and astrocytic response in the neostriatum in most animals. These results support the concept that excitatory amino acids acting through an NMDA receptor are involved in methamphetamine-induced neuronal damage on dopaminergic and serotonergic terminal fields. A minor depletion of TH-positive terminals and astrogliosis in the neostriatum was seen in three of nine MA-MK-801-treated animals. This indicates that the protective effects of MK-801 on MA-induced dopaminergic terminal degeneration varies among animals with complete protection in most animals and partial protection in the others using the present doses and dosing regimen.

Animals↗
PubMed1995

[Complications in multiple systems resulting from acute cerebrovascular diseases].

One hundred and eighty five patients died of acute cerebrovascular diseases with complications in multiple systems were studied. Statistical analyses showed that there were no organ and system failure (NOSF) in 47 cases, single organ and system failure (SOSF) in 47 and multiple organ and system failure (MOSF) in 91. Out of 90 (50%) cases who had cerebral herniation, 39 cases were complicated with SOSF and 53 cases with MOSF. Among the patients with acute brain diseases, 25% of them (46) died of SOSF (4%, 8 cases) and MOSF (21%, 38) without herniation. Incidence of failure of organ and system was higher with stomach, metabolism and lung than with heart, kidney and blood. It took on the average 24 and 12.5 hours for the first organ and system to fail and 4 days and 24 hours for the second organ in patients with intracranial hemorrhage and cerebral infarction. Occurrence of organ and system failure was closely related to sex, previous diseases and damage of brain stem, but not to the size and number of the lesion. It is suggested that cerebrogenic organ and system failure (COSF) or cerebrogenic multiple organ and system failure (CMOSF) be referred to functional failure of more than two organs or system not including brain itself as a result of acute brain diseases.

Brain Stem↗
PubMed1994

The effects of amfonelic acid, a dopamine uptake inhibitor, on methamphetamine-induced dopaminergic terminal degeneration and astrocytic response in rat striatum.

Administration of methamphetamine (MA) induces degeneration of dopaminergic nerve terminals and astrogliosis, such as hypertrophy and an increase in apparent number, in the neostriatum. In this experiment adult rats were treated with MA (10 mg/kg, i.p.) 4 times in one day at 2 h intervals. Amfonelic acid (AFA), a dopamine reuptake inhibitor, was administered (20 mg/kg, i.p.) at the same time the last MA dose was given. Three days later, dopaminergic terminals and astrocytes were examined immunohistochemically and the contents of striatal dopamine and its metabolites were analyzed by HPLC. The results showed that MA-induced the typical depletion of dopaminergic terminals, reduction of dopamine content and astrogliosis in the neostriatum. AFA treatment completely prevented the effects of MA on the dopaminergic system, both morphologically and biochemically. However, the reaction of astrocytes remained in the region where the most severe depletion of dopaminergic terminals was seen in MA treated animals (ventral-lateral portion of neostriatum). The results support the concept that the dopamine transporter is involved in MA-induced dopaminergic nerve terminal degeneration. The results also indicate that blocking the dopamine transporter cannot completely prevent the reaction of astrocytes in the neostriatum, which indicates that the astrocytic reaction can be induced by factors other than degeneration of dopaminergic terminals in this region. Based on these and other data, it is hypothesized that MA may cause degeneration of corticostriatal glutamate pathways and this effect may be responsible for the astrogliosis in MA-AFA treated animals.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1994

Design and application of PDBlib, a C++ macromolecular class library.

PDBlib is an extensible object-oriented class library written in C++ for representing the three-dimensional structure of biological macromolecules. The software design strategy, features of many of the 129 classes currently distributed with the library, and two sample applications which use the library are described. Version 1.0 of the library represents the structural features of proteins, DNA, RNA and complexes thereof, at a level of detail on a par with that which can be parsed from a Protein Data Bank (PDB) entry. However, the memory-resident representation of the macromolecule is independent of the PDB entry and can be obtained from other sources, e.g. relational and object-oriented databases. PDBlib classes are organized into four categories: (i) classes that model the macromolecule; (ii) classes that enhance the extensibility of the library; (iii) classes that provide navigation facilities of the object-oriented macromolecular structure representation; and (iv) a class that loads a PDB file into the memory-resident object-oriented representation. A number of general-purpose procedures that return features of this representation and that are relevant to all biological disciplines are included in (i). The library has been used to develop PDBtool, a prototype structure verification tool, and PDBview, a structure rendering tool that requires no specialized graphics hardware and software. Current work centers on making the macromolecular structures represented by PDBlib persistent using a commercial object-oriented database and providing an additional class library, MMQLlib, to query those structures.

Databases, Factual↗
PubMed1994

Macromolecular query language (MMQL): prototype data model and implementation.

Macromolecular query language (MMQL) is an extensible interpretive language in which to pose questions concerning the experimental or derived features of the 3-D structure of biological macromolecules. MMQL portends to be intuitive with a simple syntax, so that from a user's perspective complex queries are easily written. A number of basic queries and a more complex query--determination of structures containing a five-strand Greek key motif--are presented to illustrate the strengths and weaknesses of the language. The predominant features of MMQL are a filter and pattern grammar which are combined to express a wide range of interesting biological queries. Filters permit the selection of object attributes, for example, compound name and resolution, whereas the patterns currently implemented query primary sequence, close contacts, hydrogen bonding, secondary structure, conformation and amino acid properties (volume, polarity, isoelectric point, hydrophobicity and different forms of exposure). MMQL queries are processed by MMQLlib; a C++ class library, to which new query methods and pattern types are easily added. The prototype implementation described uses PDBlib, another C(++)-based class library from representing the features of biological macromolecules at the level of detail parsable from a PDB file. Since PDBlib can represent data stored in relational and object-oriented databases, as well as PDB files, once these data are loaded they too can be queried by MMQL. Performance metrics are given for queries of PDB files for which all derived data are calculated at run time and compared to a preliminary version of OOPDB, a prototype object-oriented database with a schema based on a persistent version of PDBlib which offers more efficient data access and the potential to maintain derived information. MMQLlib, PDBlib and associated software are available via anonymous ftp from cuhhca.hhmi.columbia.edu.

Amino Acid Sequence↗
PubMed1994

Design and application of a C++ macromolecular class library.

PDBlib is an extensible object oriented class library written in C++ for representing the 3-dimensional structure of biological macromolecules. PDBlib forms the kernel of a larger software framework being developed for assiting in knowledge discovery from macromolecular structure data. The software design strategy used by PDBlib, how the library may be used and several prototype applications that use the library are summarized. PDBlib represents the structural features of proteins, DNA, RNA, and complexes thereof, at a level of detail on a par with that which can be parsed from a Protein Data Bank (PDB) entry. However, the memory resident representation of the macromolecule is independent of the PDB entry and can be obtained from other back-end data sources, for example, existing relational databases and our own object oriented database (OOPDB) built on top of the commercial object oriented database, ObjectStore. At the front-end are several prototype applications that use the library: Macromolecular Query Language (MMQL) is based on a separate class library (MMQLlib) for building complex queries pertaining to macromolecular structure; PDBtool is an interactive structure verification tool; and PDBview, is a structure rendering tool used either as a standalone tool or as part of another application. Each of these software components are described. All software is available via anonymous ftp from cuhhca.hhmi.columbia.edu.

Animals↗