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Biomedical subjects

K Liu

Publications and source records attributed to K Liu.

At least 361 records · Page 20Linked to original sources
PubMed1995

Fundamental frequency and tracheal pressure during three types of vocalizations elicited from anesthetized dogs.

Electrical stimulation of the midbrain was used to elicit a variety of vocalizations from six anesthetized dogs. This study was conducted to investigate the ranges of and relationships between fundamental frequency of the vocalizations (F0) and tracheal pressure (Pt) produced during the vocalizations. The vocalizations were described according to type (growl, howl, and whine); F0 and Pt, as well as patterns of laryngeal muscle activity, were examined for each vocalization type. Natural-sounding growl and howl vocalizations were elicited from five dogs; three dogs also produced whines. With few exceptions, F0 was categorically different for the three vocalization types (low for growls, average for howls, very high for whines). Pt values overlapped for the three vocalization types, although, on average, howls were produced with greater Pt than growls. Patterns and degrees of laryngeal muscle activity varied across and within vocalization types, but general findings were consistent with the presumed function of most of the muscles. Laryngeal muscle activity may help explain some of the variability in the acoustic and aerodynamic data.

Anesthesia↗
PubMed1995

Epidermal morphology, cell proliferation and repopulation in mouse skin during daily fractionated irradiation.

In mouse, a 2 cm long field of both legs was irradiated daily with 3 Gy, five fractions per week for up to 3 weeks. Epidermal morphology, the circadian variation of the labelling index, and repopulation were determined at the end of each week. After a decrease of epidermal cellularity in the first week, excessive regeneration led to hyperplasia and hypertrophy, which continued throughout the experimental period while the residual tolerance of the epidermis to top-up irradiation decreased progressively. Although the repopulation rate was accelerated five-fold, it was unable to compensate the effects of more than two-thirds of the given dose. The hypertrophic and hyperplastic response is attributed to pronounced acceleration of abortive proliferation of doomed stem cells.

Animals↗
PubMed1995

Cellular, biological, and physicochemical basis for the hard-to-cook defect in legume seeds.

This review integrates current knowledge on the hard-to-cook (HTC) defect in legume seeds, with emphasis on the cellular and biological changes during storage and soaking, and the physicochemical changes during heating. Several postulated mechanisms, including the pectin-cation-phytate model, cell lignification, pectin beta-eliminative degradation, and protein denaturation in relation to starch gelatinization, are discussed in the context of current evidence. Subsequently, a developmental model of legume hardening is presented. It is held that the HTC defect develops during aging and soaking and is exhibited through cooking. During the process, there are many events involved. Free radical formation, lipid peroxidation, acid formation, membrane deterioration, protein denaturation, and leakage are events associated with aging and soaking, whereas pectin decomposition and solubilization, protein coagulation, and starch gelatinization are events that occur during cooking. Cooked HTC seeds are characterized by limited cell separation and restricted starch gelatinization. These defective features result from a restriction in pectin decomposition and solubilization as well as the protein coagulation that prevails over starch gelatinization during heating. This multichannel mechanism points to the direct involvement of two amphoteric colloids, cell wall pectin and storage protein, both of which are sensitive to pH and/or ion composition. The model also indicates the indirect involvement of cell membranes and starch granules. Except for events that occur during aging and soaking, it is likely that heat-related textural problems in other plant tissues may proceed via a mechanism similar to legume hardening.

Cell Wall↗
PubMed1995

Inadvertent epidural injection of potassium chloride. Report of two cases.

Two patients underwent thoracotomy for resection of pulmonary or esophageal carcinoma. Postoperatively, epidural catheters were inserted for pain management. Complaints of severe injection pain over the abdomen or lower extremities were made during one administration of pain medication. Progressive weakness and numbness developed over the lower trunk and lower extremities, with subsequent respiratory difficulties. Potassium chloride (KCl) was suspected to have been mistaken for normal saline as the diluent for morphine. In addition to endotracheal intubation and ventilatory support, steroids were administered both intravenously and epidurally to suppress spinal cord irritation. The two patients regain motor and sensory functions 14 and 18 hours later, respectively, without sequelae.

Humans↗
PubMed1995

Inhibition of dengue virus by novel, modified antisense oligonucleotides.

Five different target regions along the length of the dengue virus type 2 genome were compared for inhibition of the virus following intracellular injection of the cognate antisense oligonucleotides and their analogs. Unmodified phosphodiester oligonucleotides as well as the corresponding phosphorothioate oligonucleotides were ineffective in bringing about a significant inhibition of the virus. Novel modified phosphorothioate oligonucleotides in which the C-5 atoms of uridines and cytidines were replaced by propynyl groups caused a significant inhibition of the virus. Antisense oligonucleotide directed against the target region near the translation initiation site of dengue virus RNA was the most effective, followed by antisense oligonucleotide directed against a target in the 3' untranslated region of the virus RNA. It is suggested that the inhibitory effect of these novel modified oligonucleotides is due to their increased affinity for the target sequences and that they probably function via an RNase H cleavage of the oligonucleotide:RNA heteroduplex.

Alkynes↗
PubMed1995

Temperature-sensitive mutants with lesions in the vaccinia virus F10 kinase undergo arrest at the earliest stage of virion morphogenesis.

Vaccinia virus encodes two protein kinases; the B1 kinase is expressed early and appears to play a role during DNA replication, whereas the F10 kinase is expressed late and is encapsidated in virions. Here we report that the F10 kinase gene is the locus affected in a complementation group of temperature-sensitive mutants composed of ts15, ts28, ts54, and ts61. Although these mutants have a biochemically normal phenotype at the nonpermissive temperature, directing the full program of viral gene expression, they fail to form mature virions. Electron microscopic analysis indicates that morphogenesis undergoes arrest at a very early stage, prior to the formation of membrane crescents or immature virions. An essential role for the F10 protein kinase in orchestrating the onset of virion assembly is implied.

Animals↗
PubMed1995

The dual-specificity phosphatase encoded by vaccinia virus, VH1, is essential for viral transcription in vivo and in vitro.

The genetic complexity of vaccinia virus is such that as well as encoding its own transcription and replication machinery, it encodes two protein kinases and a protein phosphatase. The latter enzyme, designated VH1, is a prototype for the dual-specificity class of phosphatases. Here we report that the H1 phosphatase is encapsidated within vaccinia virions and describe the construction of a viral recombinant in which expression of the H1 gene is regulated by the presence or absence of isopropylthiogalactopyranoside (IPTG) in the culture medium. When expression of H1 is repressed, the number of viral particles produced is not compromised but the fraction of these particles which is infectious is significantly reduced. The lack of infectivity of the H1-deficient particles is specifically correlated with their inability to direct the transcription of early genes either in vitro or in vivo. A proximal role for the viral phosphatase in regulating the onset of viral gene expression is implied. Prominent among the encapsidated proteins found to be hyperphosphorylated in H1-deficient virions is the 11-kDa product of the F18 gene; this protein is the major DNA-binding component of the viral nucleoprotein complex. The ability of recombinant H1 phosphatase to reverse this hyperphosphorylation in permeabilized virions strengthens the conclusion that the F18 protein is a bona fide substrate for the H1 phosphatase.

Alleles↗
PubMed1995

[A study on growth and development of maxillofacial region with vector analysis]

In order to observe the maxillofacial growth and development quantitatively, the vector analysis was applied in this study to divide Y axis,which is advocated in Downs method,into horizontal section and vertical one,from which the ratio of the facial growth separately in anterior and inferior direction was obtained.75 pieces of x ray films for various dental stages of Shanghaiese with normal occlusion were selected and their angle of Y axis together with their cotangents were measured. The results showed that the cotangent of those with mixed,early permanent and permanent dentition were separately 0.47,0.48 and 0.45 indication that there was a certain relationship between anterior direction and inferior one for the maxillofacial region growth and development.

Journal Article↗
PubMed1995

The anesthetic management of a patient with streptococcal toxic shock-like syndrome--a case report.

Streptococcal toxic shock-like syndrome (TSLS), a severe multisystem disorder with rapid progression and fulminant course, is caused by group A beta-hemolytic streptococcal (GAS) infection. The mortality rate is around 30%. It has been reported in the United States and Europe since the 1980s. The recent recognition of this syndrome is thought to stem from the appearance of more virulent strains of streptococci with a greater tendency to produce potent exotoxins than prior ones. Early diagnosis, treatment with penicillin, radical operative debridement and adjuvant therapy with immunoglobulin and plasma exchange may bear a favourable outcome. A case of TSLS who received surgical management in operating room is presented in this paper.

Aged↗
PubMed1995

Hormonal regulation of tissue-type plasminogen activator and plasminogen activator inhibitor type-1 in cultured monkey Sertoli cells.

Sertoli cells play a central role in the control and maintenance of spermatogenesis. Isolated Sertoli cells of mouse and rat testes have been shown to secrete plasminogen activator (PA) and a plasminogen activator inhibitor type-1 (PAI-1) in culture. In this study, we have investigated the hormonal regulation of PA and PAI-1 activities in cultured monkey Sertoli cells. Sertoli cells (5 x 10(5) cells/well) isolated from infant rhesus monkey testes were preincubated at 35 degrees C for 16 h in 24-well plates precoated with poly(D-lysine) (5 micrograms/cm2) in 0.5 ml McCoy's 5a medium containing 5% of fetal calf serum and further incubated for 48 h in 0.5 ml serum-free medium with or without various hormones or other compounds. PA as well as PAI-1 activities in the conditioned media were assayed by fibrin overlay and reverse fibrin autography techniques respectively. The Sertoli cells in vitro secreted only tissue-type PA (tPA), no detectable amount of urokinase-type PA (uPA) could be observed. Monkey Sertoli cells were also capable of secreting PAI-1. Immunocytochemical studies indicated that both tPA and PAI-1 positive staining localized in the Sertoli cells, spermatids and residual bodies of the seminiferous epithelium; Northern blot analysis further confirmed the presence of both tPA and PAI-1 mRNA in monkey Sertoli cells. Addition of follicle-stimulating hormone (FSH) or cyclic adenosine monophosphate (cAMP) derivatives or cAMP-generating agents and gonadotrophin-releasing hormone (GnRH) agonist or phorbol ester (PMA) to the cell culture significantly increased tPA activity.(ABSTRACT TRUNCATED AT 250 WORDS)

1-Methyl-3-isobutylxanthine↗
PubMed1995

[Portal vein supply and embolization therapy for hepatocellular carcinoma].

To prove the necessity and feasibility of portal vein embolization for the treatment of hepatocellular carcinoma (HCC), We observed the tumor vascularity and portal vein supply by vascular casting, Doppler pulse sonography and iodized oil embolization in 178 HCC noduls. Portal vascularity was found in 75.6% of noduls (34/45). In few noduls, which were smaller than 3cm in diameter, portal branches existed only without hepatic artery branches (7/35). Tumor portal blood supply was measured in 54.1% of noduls (59/109) by using Dopplar sonography. Portal tumor branch embolization was performed in 24 of patients with unreseatable HCC, all tumor noduls being filled with iodized oil. The combined portal vein and hepatic artery embolization was more effective than hepatic artery embolization in the control of the disease (P < 0.01).

Adult↗
PubMed1995

Animal study of phoenix total artificial heart implantation.

BACKGROUND: It is well accepted that a total artificial heart (TAH) can be used as a bridge to heart transplantation during the waiting period for organ donation. A series of combined studies, conducted by the Kaohsiung Veterans General Hospital, National Yang-Ming Medical College and Municipal Tainan Hospital, has been performed to improve the Phoenix artificial heart developed by Dr. Kevin Kuo-Tsai Cheng. METHODS: In growing calves (weighed about 80 kg), standard procedures were used to remove the hearts and replace them with the TAHs. Records were made of hemodynamic data, physiological responses, blood biochemistry data and physical activities after operation and until the death of the calves. Finally, autopsies were used to determine the causes of death. RESULTS: A total of 23 calves were studied. Twenty-two of them survived 1 to 12 days, or an average 4.95 days. One survived more than 30 days. All the calves could breathe, stand, eat and void by themselves two hours after operation. Respiratory failure was the major cause of death. CONCLUSIONS: No thrombus within the TAH was noted in the last five cases, meaning that turbulent flow or dead space of the TAH was improved. Better intensive care and prevention of infection will be the next challenge for long-term use of TAH.

Animals↗
PubMed1995

[24-hour esophageal pH monitoring for suspected esophageal originated chest pain].

Thirty patients with suspected esophageal originated chest pain were studied by 24 h esophageal pH monitoring. All of them complained of chest pain, heart burn, acid reflux or dysphagia. The result showed abnormal pH in 26 patients (86.7%). Sixteen of them had pH abnormalities in both day and night, whereas 8 had only abnormal day pH, and 2 pH out of the normal limits at night. Chest pain episode was correlated with the abnormalities in 18 cases (60%). Four patients with coronary heart disease showed simultaneous gastro-esophageal reflux originated chest pain; the positive correlation was obtained. Their diagnosis of cardiac chest pain was doubtful. We suggested that 24h pH monitoring was a significant method to determine the cause of chest pain.

Adolescent↗
PubMed1995

Anesthesia for elective cardioversion: a comparison of thiopentone and propofol.

BACKGROUND: Cardioversion is still a trend of therapy for cardiac dysrhythmias. With the application of new intravenous anesthetics, cardioversion can be performed safely and effectively with rapid onset of and quicker recovery from anesthesia. We compared the anesthetic effects of a new synthetic agent, propofol, with thiopentone which was mostly used in the past. METHODS: Twenty four ASA class II to III adult patients scheduled for elective cardioversion in the coronary care unit were included in this study. All patients were given fentanyl (2 micrograms/kg, i.v.) three min before induction and were randomly assigned to receive either thiopentone 1.5 mg/kg (group 1) or propofol 1 mg/kg (group 2) for induction of anesthesia. Supplementary oxygenation was administered throughout. RESULTS: Both drugs could provide satisfactory anesthesia for elective cardioversion without major complications. Recovery time was shorter with propofol (p < 0.05). Comparing with previous reports, a higher incidence of apnea and prolonged sedation were noted in this study. This might be due to the additive effect of thiopentone or propofol with fentanyl. CONCLUSIONS: Both anesthetics were suitable for elective cardioversion with negligible side effects in hemodynamically stable patients.

Aged↗
PubMed1995

Relationship among Lewis phenotype, clotting factors, and other cardiovascular risk factors in young adults.

An increased risk of ischemic heart disease has been reported in men with the Lewis blood group phenotype Le(a-b-). We have investigated the relationship between Lewis phenotype and cardiovascular risk factors in 1714 participants in the Coronary Artery Risk Development in Young Adults Study, an ongoing investigation on life-styles and evolution of cardiovascular risk factors. No significant differences were observed among Lewis phenotypes for body mass index, blood lipid levels, blood pressure, or clotting factors VII and fibrinogen. However, in white men with blood groups A, B, or AB, and the Le(a-b-) phenotype, significantly higher levels of factor VIII (p < 0.01) and von Willebrand factor (p < 0.03) were observed than in those with other Lewis phenotypes (Le[a+b-] or Le[a-b+]). Two-way analysis of variance indicated a significant interaction between blood group and Lewis phenotype (p = 0.0053) in terms of relationship to factor VIII. A similar trend was observed in black men with blood type A, B, or AB, and phenotype Le(a-b-) for factor VII/von Willebrand factor and in women with blood type A, B, or AB, and phenotype Le(a-b-) for factor VIII. Our data suggest that the Le(a-b-) phenotype and blood groups A, B, and AB, by virtue of their association with raised levels of factor VIII and von Willebrand factor, may be risk markers for future atherothrombotic disease.

ABO Blood-Group System↗