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Biomedical subjects

F Cai

Publications and source records attributed to F Cai.

At least 37 records · Page 2Linked to original sources

Effect of sciatic nerve crush on local and target tissue production of neurotrophin-3 transcripts in rats.

The effect of sciatic nerve crush in adult rats on neurotrophin-3 (NT-3) mRNA expression at the site of crush and in ipsilateral foot skin was studied using competitive reverse transcription-polymerase chain reaction (cRT-PCR). Mid-sciatic nerve crush resulted in a significant reduction in the expression of NT-3 mRNA in nerve segments distal to the injury site at 3 and 7 days (approximate 60% decrease; P < 0.01). The reduced NT-3 rnRNA expression started to increase at days 14 post-crush and returned towards control levels at 21 days following the crush. The nerve segment proximal to the crush site showed a similar changed pattern of NT-3 mRNA expression. The effects of denervation on NT-3 mRNA expression in foot skin were also studied. Reduced expression of NT-3 was observed by 7 days post-crush, with a 25% decrease observed by 14 days (P < 0.002). Levels of NT-3 mRNA had returned to normal by 21 days post-crush. The results show that changes in axon-Schwann cell contact do not account for the nerve crush induced loss, or subsequent recovery, of NT-3 mRNA expression in nerve.

Animals↗

Keratoconjunctivitis sicca associated with achalasia of the cardia, adrenocortical insufficiency, and lacrimal gland degeneration: Keratoconjunctivitis sicca secondary to lacrimal gland degeneration may parallel degenerative changes in esophageal and adrenocortical function.

OBJECTIVE/DESIGN: This study aimed to examine and describe three siblings with alacrima, the eldest of whom had associated achalasia and adrenocortical insufficiency. PARTICIPANTS: Three affected siblings and four age-matched control subjects participated. INTERVENTION/MAIN OUTCOME MEASURES: The three children underwent complete ophthalmologic examinations; computed tomographic scanning of brain, orbit, chest, and abdomen; and measurement of serum cortisol. All three were subjected to a short synacthen challenge. Lacrimal gland biopsies were performed on the two younger subjects, and specimens were studied by light and electron microscopy. RESULTS: All three children showed virtually absent tear secretion as tested by the Schirmer test. The resulting keratopathy was most severe in the oldest child, who developed bilateral corneal melting. The two younger children showed interpalpebral corneal staining with rose bengal. All three children improved after punctal occlusion. Addison's disease was present in the oldest child. Computed tomographic scanning showed absent lacrimal and shrunken adrenal glands in association with achalasia of the cardia in the oldest child. The lacrimal glands were found to be reduced in size in the next eldest child. When evaluated by electron microscopy, the lacrimal gland biopsy specimens from the two younger children showed neuronal degeneration associated with depletion of secretory granules in the acinar cells. CONCLUSION: In this disease, radiologic evidence of reducing lacrimal gland size with increasing age could represent a degenerative process. This may be paralleled by other signs and the possibility of adrenocortical insufficiency and achalasia of the cardia should be investigated in all children presenting with dry eyes. These children appear to have a progressive neuronal disease.

Adrenal Cortex↗

Study of nerve conduction and late responses in normal Chinese infants, children, and adults.

Healthy Chinese individuals (n = 168), aged from 24 hours to 30 years, were studied to establish the following normal values: (1) motor conduction velocity, distal latency, amplitude, and F-wave velocity in the median, ulnar, tibial, and peroneal nerves; (2) H-reflex velocity and latency in the tibial nerve for all subjects as well as in the median and ulnar nerves in infants; (3) sensory conduction velocity, latency, and amplitude in the median, ulnar, and sural nerves; and (4) the difference in minimal latencies of both H-reflex and F-waves between corresponding nerves in opposite limbs and between two nerves in the same limb. The motor conduction velocities, sensory conduction velocities, F-wave velocities, and H-reflex velocities in newborns were approximately 50%, 40%, 40 to 45%, and 40 to 45% of adult values, respectively. At age 3 years, the normal values were in the adult range for all motor conduction velocities and for the sensory conduction velocities in the upper limbs. The sensory conduction velocities, H-reflex velocities, and F-wave velocities in the lower limbs did not reach adult values until age 6 years whereas the upper limb F-wave velocities reached adult levels between 6 and 14 years in different nerves. These results indicate that adult values for nerve conduction velocities, including the late responses, are reached earlier in the lower extremities; however, conduction velocities at any age are always faster in the upper limbs and in the proximal compared to the distal segments. The maturation process occurs most rapidly during the first 3 to 6 years of life, especially in the first year. This parallels the histologic development of peripheral nerves during childhood.

Action Potentials↗

Analysis of continued economic progress in China.

"This paper uses...historic and theoretical points of view to explain continued economic progress [and to refute] some incorrect views regarding China's economic progress. One view in this paper deals with how China's continued economic progress could burden and threaten [the world]. Another view...analyzes the government's improper policy toward the relationship among China's modern population, resources, and environment."

Asia↗

[Analysis of survival in 240 patients with unresectable primary hepatocellular carcinoma treated with hepatic artery chemo-embolization].

The effect of transcatheter hepatic artery chemoembolization (TAE) on hepatocellular carcinoma (HCC) was evaluated. The survival time of 240 patients with unresectable primary HCC who were treated by TAE during the period from Jan. 1987 to Jan. 1995 were followed up. The results showed that in this series the overall 1-, 2-, 3-, 5- and 7-year survival rate was 61.0%, 39.2%, 30.7%, 18.9%, 16.0%, respectively. The survival rate of patients treated with TAE plus hepatectomy at 1, 2, 3, 5 and 7 years was 95.2%, 90.4%, 85.0%, 59.0% and 59.0% respectively, while that in patients treated with TAE in 1, 2, 3, 5, 7 years was 58.1%, 34.0%, 24.4%, 13.7%, 9.1%, respectively. This results indicate that TAE therapy is a treatment of choice for patients with advanced hepatocellular carcinoma.

Adolescent↗

Predicted structure of the adenovirus DNA binding protein.

The DNA sequence of a portion of the MAV1 SmaI-D fragment coding for the C-terminal 147 amino acids of the adenoviral DNA-binding protein (DBP) has been determined. A multiple sequence alignment was constructed of the MAV1 fragment and the DBPs of Ad.2, 4, 5, 7, 12, 40, and 41 to examine the degree of conservation of features that have been mapped on the Ad.2 DBP and to identify further conserved features. The less conserved N-terminal segment of the protein contains two nuclear localization signals and two acidic regions, the host range region, and all of the 11 phosphorylation sites. The highly conserved C-terminal segment contains a potential leucine zipper and zinc finger motifs. These sequence features were mapped onto a predicted secondary structure of the Ad.2 DBP.

Adenoviridae↗

Adenovirus protease expressed in insect cells cleaves adenovirus proteins, ovalbumin and baculovirus protease in the absence of activating peptide.

The adenovirus type 2 protease (EP) was expressed by infecting insect cells with a recombinant baculovirus. Immunoblot and activity analysis showed EP to be present in both the nucleus and cytoplasm. While the insect cell expressed EP was more soluble than the Escherichia coli expressed EP, its activity was one quarter of the latter, suggesting that eukaryotic postsynthetic modifications are not essential for enzyme activity. EP inactivated a cytoplasmic cathepsin-like baculovirus-encoded cysteine protease which carries a single EP cleavage site and which was capable of digesting most adenovirus structural proteins in vitro. In addition to cleavage of the baculovirus protease, the adenovirus EP was also able to cleave ovalbumin and canine adenovirus protein pre-VII, in the absence of activating peptide. EP activation therefore may occur by means of factors other than the specific activating peptide.

Adenoviruses, Canine↗

A new and cheap medical examination system with artificial intelligence.

This is a medical examination system with artificial intelligence. It is used to find persons who want to obtain higher professional posts in the medical field, including doctors, dentists, nurses, pharmaceutists, etc. It has a question bank of 536,000 multiple choice questions (MCQs), of which 59,500 have pictures. Ten percent of the MCQs is updated every year; the old MCQs in the question bank are used as exercises for the persons who want to obtain higher professional posts. The system, with three distinctive degrees of difficulty, is applicable to three different professional posts: the assistant physician, the resident, and the attending physician. It ensures the general level of assessment for the same professional post, regardless of when one wants to take the system. In addition, the system also guarantees the consistency of the following three factors: the constituent of sub-professions, the classification of MCQs, and the degree of difficulty of each MCQ. Another feature of the system is that the passing score need not be the traditional standard passing score of 60. The passing score is determined by the system according to the requirements of the different professional posts and the degree of difficulty of the MCQs in the system. Therefore, the new method for passing the system is more rational than the traditional one. Moreover, the final score given by the system will be standardized to eliminate sampling errors. The reliability of the system will also be tested after each examination. If the coefficient of reliability is lower than 0.85, the scores will be canceled and examination will be repeated. The system can accept 96 persons simultaneously taking the examination with on-line computers. The people who work in remote places can take examination in their hospital with a personal computer linked via telephone. The system has already been approved by the relevant authoritative departments in China. It has been running successfully for more than six years. During this period of time, 125,645 candidates have taken the exam; 64,078 have passed the examination and have been promoted to higher professional posts. The system runs on local area network and uses a program written in PROLOG and FoxPro. It is estimated that the total cost of developing the system is less than $46,000 (US).

Artificial Intelligence↗

Sequence and structural analysis of murine adenovirus type 1 hexon.

The genomic region encoding the major capsid protein (hexon) of murine adenovirus type 1 (MAV-1) has been isolated and sequenced. The sequence predicts a 908 residue MAV-1 hexon protein and is flanked by a portion of the upstream pVI gene and the downstream endoproteinase gene. The order of these genes and their location in the middle of the genome are the same as those found in other adenoviruses sequenced to date. Multiple sequence alignment with the other five known hexon protein sequences reveals an overall residue identity of 51% and residue conservation of 66%. In comparison with human adenovirus type 2 (Ad2), MAV-1 hexon has major deletions between residues 141 to 170, 270 to 284 and 446 to 455. Since these regions in the Ad2 hexon are partially exposed on the outer surface of the virion, they may represent type-specific antigenic determinants. The MAV-1 hexon sequence has been modelled using the known three-dimensional structure of the Ad2 hexon. The variable regions in which the mutations, deletions and insertions occur are located in the l1 and l2 loops of the molecule that form the protruding hexon towers on the external surface of the virion.

Amino Acid Sequence↗

Diurnal change and prolonged dark effect on myeloid bodies in the retinal pigment epithelium of the leopard frog.

Myeloid bodies (MBs) are multi-lamellar membrane structures which are widely distributed in the retinal pigment epithelium (RPE) of lower vertebrates. The functional significance of these organelles is not known, but they are believed to be associated with lipid processing in the retina. To determine the nature of the daily changes which occur in MBs, and to ascertain the best sampling time for MB isolation as a prelude to the biochemical characterization of these organelles, this study has assessed the occurrence and area density of MBs in the leopard frog (Rana pipiens) over a daily light-dark cycle. Eye tissues from light-entrained (12L:12D) frogs were sampled at 1, 4, 7, 10 hr after both lights-on and lights-off (n = 5). In addition, to determine whether MB formation is a circadian or light-driven event, the effect of a period of prolonged darkness on MB formation was also examined by maintaining frogs in the dark for an additional 1, 4, 7, and 10 hr at the end of a normal dark phase (n = 5). The number and area density as a percentage of total RPE cell area (area %) for phagosomes (PGs), oil droplets (ODs) and MBs were determined morphometrically using light and electron microscopy. Data were analyzed by a nested analysis of variance. Results indicated that: 1) PG numbers were elevated significantly following lights-on and were reduced almost to nil in the late dark period.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

Organization of the avian adenovirus genome and the structure of its endopeptidase.

In the search for the endopeptidase gene, short segments of genomic DNA were sequenced from the avian adenovirus type 1 (CELO) HindIII C and G fragments. On the basis of homology of the translated segments to Ad2 proteins, the genes for hexon, endopeptidase, DNA-binding protein, and 100K protein were mapped in that order between map units 41 and 63. The endopeptidase gene was encoded within a 900 nucleotide segment extending leftward from the EcoRI site at coordinate 50. The predicted Aavl endopeptidase consists of 206 residues of which 66% are similar to the sequence of the human Ad2 enzyme. Alignment of the known endopeptidase sequences identifies a single conserved histidine (H54) and two conserved cysteine residues (C104, C122) as likely candidates for the catalytic site of this thiol proteinase.

Amino Acid Sequence↗

Effect of photoreceptor outer segment disk shedding on myeloid body formation in the retinal pigment epithelium of the leopard frog.

To test the hypothesis that myeloid body (MB) formation results from the shedding of retinal photoreceptor outer segments and the consequent degradation of lipids derived from outer segment disk membranes, the effect of massive outer segment shedding and the disruption of such outer segment shedding on MB formation were examined in the leopard frog. Light entrained frogs were first placed in constant light (700 lux) for 48 hours to inhibit shedding, followed by a 1.5 hours dark priming either in vivo or in vitro, and then returned to light for an additional 4 hours which results in massive outer segment shedding. To serve as a control, the effect of shedding disruption on MB formation was assessed in vivo using light manipulation to inhibit shedding, or mechanical removal of the neurosensory retina in vitro. The results indicate that although the phagosome numbers were clearly elevated in the samples taken from either in vivo or in vitro eye-cup preparations where outer segment shedding had been stimulated, there was no significant concomitant increase in Mbs number over controls kept under constant light for 48 hr or constant light 48 hr plus 1.5 hr in dark, where MBs represent approximately 5% of the total RPE cell area. In contrast, when shedding was interrupted either by removal of the neural retina immediately after in vitro eye-cups were returned to light or by maintaining frogs in dark without light stimulation, the RPE cells contained very few phagosome, yet in both conditions RPE cells showed a two-fold increase in MB area over the shedding-stimulated controls (p = 0.0001).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

[Application of RFLP analysis to Duchenne and Becker muscular dystrophy in Shandong Province. I. Carrier detections in females at risk].

There were eight intragenic and two flanking bridge DNA polymorphic markers used in the RFLP analysis in 21 Duchenne and Becker muscular dystrophy selected from nine different districts in Shandong Province. A total number of 173 individuals of the families were accepted for gene tracking and carrier detection, as well as prenatal diagnosis. Based on the frequency of the probe polymorphism tested in our study of 53 unrelated individuals, one to three high polymorphic probes were sequentially used and all families presented the informativeness in RFLP analysis. Some more introgenio probes were supplied for assessment of mutated sites and carrier status with the help of gene phases, if recombinations were found. Our results presented a ratio of 85.45% of carrier detection at risk females with 95% or more reliability, including 17 carriers and 30 non-carriers. It was not able to ascertain the carrier status of 8 females because of DNA absence from key family members. Finally, we proposed a diagnostic procedure for the RFLP analysis to DMD/BMD families.

Female↗

Primary structure of the canine adenovirus PVII protein: functional implications.

The DNA sequence of an open reading frame (ORF) corresponding to the canine adenovirus type 1 (Can 1, Utrecht strain) pro-VII (PVII) protein gene was determined. 560 base pairs were sequenced from the upstream end of the HindIII-A genomic fragment. The sequence gives the 33 C-terminal residues of the penton base protein followed by the 132 residue PVII protein, thus conforming to the same order and location of these genes as in Ad2. The authenticity of this putative PVII-ORF was confirmed by N-terminal sequencing of the cleavage product VII isolated from Can1 virions and also by PCR analysis of Can1 DNA from infected cells and from virions. In addition, the sizes of PVII and VII obtained from translation of the sequence and the proteins observed on the gels were also in agreement. The PVII proteins of Can1 and Ad2 share 57% sequence homology, particularly near the N-terminal third of the molecule, including conservation of the consensus proteinase cleavage site at residue 23. The PVII protein has a predicted MW of 14,626 Da, and an pI of 12.48. Though data bank searches for homology were negative, these viral proteins have significant functional and sequence analogy with histone H3.

Adenoviridae↗

Primary structure of the murine adenovirus type 1 proteinase.

The DNA sequence of an open reading frame (ORF) corresponding to the murine adenovirus type 1 (Mav1) proteinase gene was determined. 1162 base pairs were sequenced from the downstream end of the SmaI-D Mav1 genomic fragment. The sequence defines the 204 amino acid proteinase, which apparently does not possess the usual L3 polyadenylation signal, but instead the sequence AAATAA. This gene is followed by a 147 amino acid C-terminal portion of the DNA-binding protein, encoded by the complementary strand.

Adenoviridae↗

Nucleotide and deduced amino acid sequence of the canine adenovirus type 1 proteinase.

The DNA sequence of an open reading frame (ORF) corresponding to the canine adenovirus type 1 (Can1) proteinase gene was determined. A total of 1171 base pairs were sequenced from the downstream end of the HindIII-A Can1 genomic fragment, including adjacent regions corresponding to the carboxy-terminal portions of the hexon and the DNA-binding proteins. The predicted Can1 proteinase consists of 206 residues (23,325 D) of which 68% are identical and 83% are similar to the sequence of the human Ad2 proteinase. Alignment with the Ad2 proteinase identified a number of conserved residues that could form part of the catalytic triad of the enzyme.

Adenoviridae↗