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Biomedical subjects

C C Chu

Publications and source records attributed to C C Chu.

At least 127 records · Page 7Linked to original sources
PubMed1990

Psychiatric applications of bromocriptine therapy.

Bromocriptine, an ergot alkaloid derivative that possesses both dopamine agonist and antagonist activity, has been studied in a broad spectrum of psychiatric illnesses. The literature consists primarily of case reports and small trials limited by methodological shortcomings. The authors critically review these reports, focusing on efficacy, mechanistic issues, dosing, side effects, predictors of response, monitoring parameters, and practical guidelines. Preliminary data suggest bromocriptine may have promise in the treatment of neuroleptic malignant syndrome, cocaine withdrawal, and depression. At present, the agent appears less efficacious in the treatment of tardive dyskinesia, mania, and schizophrenia; however, doses in these trials may have been excessive, producing primarily postsynaptic agonist effects. More extensive clinical trials are required to clearly define the role of bromocriptine in psychiatry.

Bromocriptine↗
PubMed1989

A 10- rather than 9-bp duplication associated with insertion of Tn5 in Escherichia coli K-12.

The composite transposable element Tn5, which is made up of two inverted IS50 elements surrounding genes encoding drug resistance, generally generates 9-bp duplications at the site of insertion. In our studies of three Tn5 insertion mutants at one location in the Escherichia coli chromosome, we have observed that one contains a duplication of 10 bp, while the other two have the usual 9-bp duplication. Three other insertion elements, IS1, IS4, and IS186, give variable-sized target site sequence duplications. We observed a similarity of amino acid sequence in a small region of the putative transposases among IS4, IS186, and Tn5 suggesting a conservation of function in this group of transposases.

Amino Acid Sequence↗
PubMed1989

Suppression of a frameshift mutation in the recE gene of Escherichia coli K-12 occurs by gene fusion.

The nucleotide sequences of a small gene, racC, and the adjacent N-terminal half of the wild-type recE gene are presented. A frameshift mutation, recE939, inactivating recE and preventing synthesis of the active recE enzyme, exonuclease VIII, was identified. The endpoints of five deletion mutations suppressing recE939 were sequenced. All five delete the frameshift site. Two are intra-recE deletions and fuse the N- and C-terminal portions of recE in frame. Three of the deletions remove the entire N-terminal portion of recE, fusing the C-terminal portion to N-terminal portions of racC in frame. These data indicate that about 70% of the N-terminal half of recE is not required to encode a hypothesized protein domain with exonuclease VIII activity.

Amino Acid Sequence↗
PubMed1989

Sex differences in schizophrenia.

Demographic and clinical characteristics of 275 schizophrenics consecutively admitted to seven hospitals were examined. Males were younger than females when first hospitalized, diagnosed and treated. Psychiatrists rated on two rating scales by using a structured interview to compare the symptomatology. Female schizophrenics were more agitated, inappropriate, silly, irrelevant, over-talkative, and exhibiting more flight of ideas, while male schizophrenics were more slowed, hypoactive, grandiose, withdrawn, and showing more blocking, auditory hallucinations and poor communications. Katz Adjustment Scales were rated by the patients and their relatives. Female schizophrenics were perceived by relatives to be more helpless and withdrawn-depressed than male schizophrenics.

Adult↗
PubMed1989

[Clinical analysis and study of hypospadias].

We did a retrospective survey on 117 patients with hypospadias to determine what other congenital anomalies were present. We confirm the increasing incidence of chordee with severity of hypospadias. There were many other systemic anomalies associated with hypospadias. We found nongenitourinary tract malformations as follows: neuromuscular 1.7%, gastrointestinal 4.3%, cardiovascular 3.4%, ENT 0.8%, eye 0.8%. The incidence of genitourinary tract anomalies associated with hypospadias was 24.8% (undescended testis 11.1% and hernia 6.0%). Intravenous pyelography should be reserved for a selected group of children with hypospadias with abnormal ultrasonograms or urologic symptomatology. The primary therapeutic approach is surgical. Urethra-cutaneous fistula requiring additional surgery may occur following hypospadias repair in about 29.0% of cases in this paper.

Adolescent↗
PubMed1989

Quantitative evaluation of stiffness of commercial suture materials.

The bending stiffness of 22 commercial suture materials of varying size, chemical structure and physical form was quantitatively evaluated using a stiffness tester (Taber V-5, model 150B, Teledyne). The commercial sutures were Chromic catgut; Dexon (polyglycolic acid); Vicryl (polyglactin 910); PDS (polydioxanone); Maxon (polyglycolide-trimethylene carbonate); Silk (coated with silicone); Mersilene (polyester fiber); Tycron (polyester fiber); Ethibond (polyethylene terephthalate coated with polybutylene); Nurolon (nylon 66); Surgilon (nylon 66 coated with silicone); Ethilon (coated nylon 66), Prolene (polypropylene); Dermalene (polyethylene), and Gore-tex (polytetraflouroethylene). These are both natural and synthetic, absorbable and nonabsorbable and monofilament and multifilament sutures. All of these sutures were size 2-0, but Prolene sutures with sizes ranging from 1-0 to 9-0 were also tested to determine the effect of suture size on stiffness. The bending stiffness data obtained showed that a wide range of bending stiffness was observed among the 22 commercial sutures. The most flexible 2-0 suture was Gore-tex, followed by Dexon, Silk, Surgilon, Vicryl (uncoated), Tycron, Nurolon, Mersilene, Ethibond, Maxon, PDS, Ethilon, Prolene, Chromic catgut, coated Vicryl, and lastly, Dermalene. The large porous volume inherent in Gore-tex monofilament suture was the reason for its lowest flexural stiffness. Sutures with a braided structure were generally more flexible than those of a monofilament structure, irrespective of the chemical constituents. Coated sutures had significantly higher stiffness than the corresponding uncoated ones. This is particularly true when polymers rather than wax were used as the coating material. This increase in stiffness is attributable to the loss of mobility under bending force in the fibers and yarns that make up the sutures. An increase in the size of the suture significantly increased the stiffness, and the magnitude of increase depended on the chemical constituent of the suture. The flexural stiffness of sutures was also found to depend on the duration of bending in the test for stiffness. In general, monofilament sutures exhibited the largest time-dependent stiffness. This was most pronounced with the Gore-tex suture. Most braided sutures also showed less time-dependence in stiffness. Nylon sutures did not exhibit this time-dependent phenomenon regardless of physical form.

Elasticity↗
PubMed1988

The study of thermal and gross morphologic properties of polyglycolic acid upon annealing and degradation treatments.

The objective of this study is to alter the fiber morphology of a linear aliphatic polyester, polyglycolic acid, by annealing treatment and to examine the changes of its degradation properties. The annealing was done at 150 degrees C, 170 degrees C, and 190 degrees C, and the specimens were annealed in four different strained conditions, freely hung, 0, 1, and 10%. After annealing treatments, the specimens were subject to in vitro hydrolytic degradation by immersing them in phosphate-buffer solution of pH 7.4 at 37 degrees C for up to 28 days. The thermal properties and gross morphology of the specimens were obtained. It was found that annealing treatments resulted in initial higher levels of crystallinity, which, in turn, influenced the hydrolytic degradation of the fiber. Among all the annealing conditions, the freely hung specimens annealed at 190 degrees C exhibited the most pronounced annealing effect on hydrolytic degradation, and was consistent with the observed gross morphologic changes. The change in the characteristics of fiber structure (i.e., the return to the stage of less oriented conformation upon freely hung annealing) was thought to be the cause.

Biocompatible Materials↗
PubMed1988

Physical assaults in a psychiatric unit of a general hospital.

The authors collected data concerning assaults, assaultive patients, and victims in a psychiatric unit during a 12-month period and compared them with data from a control group of patients. Thirty-seven assaults by 25 patients were recorded. Fourteen of the victims were patients and 23 were members of staff. The assaultive group contained a significantly higher proportion of schizophrenic patients than did the control group and significantly larger numbers of patients from lower socioeconomic classes, patients admitted involuntarily under a section of the Mental Health Act, and patients with a history of assaults.

Adult↗
PubMed1987

Newly made antibacterial braided nylon sutures. I. In vitro qualitative and in vivo preliminary biocompatibility study.

A new type of braided nylon thread with a silver compound coating was made for the purpose of designing a biocidal suture material. The study used standard bacterial culture techniques to evaluate the antibacterial property of the new Ag-coated nylon thread. Seven types of bacterial species were tested; S. aureus, E. coli, P. aeruginosa, K. pneumoniae, S. dysenteriae, S. maruslens, and P. mirabilis. The commercial size 2/0 Nurolon suture from Ethicon served as the control. A weak direct current ranging from 0.4-400 microA was applied to the specimens to examine whether the biocidal property of silver could be enhanced by current. The antibacterial property was evaluated by the width and sterility of the clear zone in the bacterial culture plates. It was found that the new nylon thread exhibited very good to moderate bactericidal property toward these seven bacterial species. P. aeruginosa was the most sensitive species, while P. mirabilis was the least sensitive one. Application of direct current through the Ag-coated specimens positively enhanced their antibacterial property and the degree of enhancement depended on the direct current level. The material also exhibited an antibacterial property toward well-established bacterial colonies, but the effect was less strong than the case when direct current was applied simultaneously with incubation. Silver ions released from the coated nylon thread were responsible for the observed antibacterial property; and the application of a weak direct current to the material enhanced this effect. A preliminary biocompatibility study of this new material in rat gluteal muscle indicated that the new material caused less inflammatory reaction than the control Nurolon suture up to 60 days after implantation.

Animals↗
PubMed1987

In vitro quantitative study of newly made antibacterial braided nylon sutures.

This study was done to examine quantitatively the antibacterial property of a newly made, silver compound coated braided nylon suture and to confirm the previously reported qualitative antibacterial data. Three representative bacterial species were used and they were Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa. The suture specimens were embedded in a custom built plastic device filled with a fixed concentration of bacteria for predetermined periods of incubation. A direct current ranging from 0.4 to 40.0 microamperes was applied to the suture specimens. The bacterial suspension was periodically removed for a standard plate count in order to determine quantitatively the antibacterial capability of the suture specimens. The amounts of silver ions released to the medium under various direct current levels were also determined by a pH/ion meter. The antibacterial property of the suture was evident in the anode site of the material, and at a fixed current, the degree of bacteriostatic effect depended upon the type of bacterial species. For example, a difference of almost 10(3) in the number of Pseudomonas aeruginosa was observed within a period of six hours. The responses of Staphylococcus aureus and Escherichia coli to the silver compound coated nylon thread, however, were not as drastic as Pseudomonas aeruginosa. These quantitative data were consistent with the previously reported qualitative observation of the width of clear zone in bacterial culture plates. The silver ion concentration in the medium increased with increasing either the current level or time, or both. At the end of six hours, the ion concentrations were 7.3 micrograms per milliliter at 0.4 microampere, 44.3 micrograms per milliliter at 4.0 microamperes and 305.7 micrograms per milliliter at 40.0 microampere.

Anti-Bacterial Agents↗
PubMed1986

Symptom differences between urban and rural schizophrenics in Turkey.

The symptomatology of Turkish urban and rural schizophrenic patients was compared in 94 consecutive hospital admissions. These were rated on two rating scales by psychiatrists, using a structured interview. Urban patients were more frequently anxious, tense, stiff, rigid, perseverating and depersonalized than rural patients; urban patients also exhibited more frequent symptoms of outbursts, blocking, thought pressure, depressed mood and somatic concern than their rural counterparts. Rural patients were more often withdrawn, disoriented, confused/delirious and lacking contact in communication than urban patients; rural patients also showed more frequent symptoms of flight of ideas and consciousness lapses than their urban counterparts.

Adult↗
PubMed1985

Characterization of morphologic and mechanical properties of surgical mesh fabrics.

The objective of this study is to use standard testing methods to characterize the currently available synthetic mesh fabrics in terms of their chemical, physical, mechanical, and morphologic properties. Three commonly used surgical mesh fabrics, Mersilene (Ethicon), Marlex (Davol), and Teflon (USCI), were used, and the tests reveal that they differ from one another chemically as well as configurationally. The experiment included an identification of the structure of the yarn and fabrics; a measurement of the porosity, pore size and shape; and a determination of tensile and bursting strength, flexural rigidity, and wrinkle recovery. A wide variation in structure and performance was observed among the three mesh fabrics. Mersilene mesh fabrics have the highest relative porosity, while Marlex and Teflon meshes have an equivalent, but lower value. Marlex meshes have the highest tensile and bursting strength followed by Teflon and Mersilene meshes. All three meshes have one common strength characteristic--a distinctive difference in tensile strength between the wale and course directions. Marlex mesh fabrics exhibit an immense flexural rigidity and poor wrinkle recovery, due mainly to the monofilament structure of the yarn. Mersilene and Teflon mesh fabrics have similar but considerably lower, flexural rigidity than Marlex. Thus, it is evident that the chemical nature of the constituent fibers, as well as the yarn and fabric structure, have a great effect on the performance of the resulting mesh fabrics. The availability of this characterization data can serve as the basis for a surgeon's selection of the most appropriate commercial surgical mesh fabric for each case, as well as to provide a foundation for the subsequent comparison of their in vivo performance.

Materials Testing↗
PubMed1985

Neuroendocrine investigation of depression in mentally retarded patients. A pilot study.

As part of a pilot study, eight adults with severe mental retardation were screened for the presence of endogenous depression by the standard 1-mg overnight dexamethasone suppression test (DST). The eight had been rigorously screened to rule out potential for false-positive DST. Two of the eight patients demonstrated nonsuppression, and a third had borderline results. Of these three, two manifested behavioral disturbances that could be attributed to major depressive disorder. The authors discuss the results, the difficulty diagnosing psychiatric disorders in severely retarded persons, and the proposed utility of the DST in this area.

Adult↗
PubMed1985

Patterns of psychiatric consultation in a Chinese general hospital.

The authors conducted a study of psychiatric consultation in a Chinese general hospital. Seventy-five inpatients (0.74% of the patients in the hospital) were referred by different services over a 1-year period. Internal medicine referred the most patients, and organic brain syndromes were the most common diagnoses. Depression was not a frequent diagnosis, but neurasthenia was a fairly common one. None of the referred patients had a diagnosis of alcoholism, drug abuse, or personality disorder. The authors compare these data with those of Western studies and discuss the possible factors influencing psychiatric consultation in China.

Adolescent↗