Search PubMed⌕ Search

Biomedical subjects

Zhi Liu

Publications and source records attributed to Zhi Liu.

At least 37 records · Page 2Linked to original sources

Incomplete emptying and urinary retention in multiple-system atrophy: when does it occur and how do we manage it?

Neurogenic urinary retention can be a major cause of morbidity in multiple-system atrophy (MSA). However, the timing of its appearance has not been entirely clear, and neither have the medical and surgical modalities for managing patients. We present the data obtained from our uroneurological assessment and therapeutic interventions at various stages of MSA. We recruited 245 patients with probable MSA. We measured postvoid residuals (PVR) and performed EMG cystometry in all patients. The grand average volume of PVR was 140 mL (range, 0-760) in our patients. The average PVR volume was 71 mL in the first year, increasing to 129 mL in the second year and 170 mL by the fifth year. The percentages of patients with complete urinary retention, acontractile detrusor, and detrusor-sphincter dyssynergia (DSD) also increased. The increase in PVR resulted in a decrease in functional bladder capacity, together with an increase in detrusor overactivity and neurogenic sphincter EMG. Clean intermittent self-catheterization (CISC) was introduced in most patients. Bladder-oriented therapy (cholinergic agents) had a limited value, whereas urethra-oriented therapy benefited patients with DSD (surgery) for up to 2 years, but syncope occurred in a subset of patients (alpha-blockers). MSA patients present with large PVR by the second year of illness, and that large PVR secondarily causes urinary frequency. CISC is the recommended treatment for most patients. Urethra-oriented medication and surgery benefit patients who would have difficulty performing CISC, although careful consideration of the short-term efficacy and potential adverse effects of these alternatives is mandatory.

Adrenergic alpha-Antagonists↗

Neurological diseases that cause detrusor hyperactivity with impaired contractile function.

AIMS: Detrusor hyperactivity with impaired contractile function (DHIC) was originally described in elderly women. It has not previously been well known whether neurological diseases cause DHIC. We investigated which neurological diseases commonly cause DHIC in our laboratory. MATERIALS AND METHODS: We searched for DHIC in our laboratory's computerized database of 1,514 case records, which included a lower urinary tract (LUT) symptom questionnaire and urodynamic study results. DHIC was defined as the presence of both (1) detrusor overactivity during the storage phase, and (2) underactive detrusor contraction during the evacuation phase. RESULTS: Two hundred and seventeen patients met the criteria for DHIC: 122 men and 95 women; mean age, 63 years. The neurological diseases that caused DHIC included Parkinsonian syndrome (18%), multiple system atrophy (18%), progressive supranuclear palsy/corticobasal degeneration (14%), multiple cerebral infarction (MCI) (12%), multiple sclerosis/acute disseminated encephalomyelitis (18%), spinal cord lesions (15%), and cervical spondylotic myelopathy (CS) (10%). CONCLUSIONS: The present study revealed that a wide spectrum of neurological disorders could cause DHIC.

Adult↗

Bladder sensation in peripheral nerve lesions.

OBJECTIVE: To present bladder sensory data of three common peripheral nerve lesions (e.g., distal, intermediate/focal, and proximal). METHODS: We measured first sensation (FS) and bladder capacity (BC) (not exceeding 600 ml) in 71 patients with peripheral nerve lesions: 35 diabetic neuropathy (D group), 6 post-pelvic surgery (S), and 27 cauda equina syndrome due to lumbar spondylosis (L). We excluded those with detrusor overactivity or low compliance that might affect bladder sensation. RESULTS: The mean FS was 301.7 ml (D), 271.3 ml (S), and 189.4 ml (L), with the largest being in the D group (P < 0.05); the mean BC was 495.2, 475.4, and 391.4 ml, with the largest being in the D group (P < 0.05); who commonly had less frequent toileting. The mean post-void residual volume was 106.5, 29.0, and 42.0 ml; the values tended to increase along with BC. In the D group, the mean FS in patients with skin hypoalgesia as detected by pin prick and in those without it was 407.8 and 210.0 ml. The percentage of patients with FS < 100 ml was 5.7%, 0%, and 7.4%, respectively, who commonly had urinary urgency and frequency. CONCLUSIONS: Bladder sensation is affected in diabetic neuropathy more severely than in intermediate/proximal lesions, together with somatic sensory disturbance. Bladder sensory disturbance leads to less frequent toileting, resulting in bladder over-distension and large post-void residuals. A small proportion of patients with peripheral nerve lesions develop urinary urgency, presumably reflecting irritation of the afferent nerve fibers or the urothelium.

Aged↗

Urinary dysfunction and autonomic control in amyloid neuropathy.

Uro-neurological assessment was performed in four patients with small-fiber neuropathy due to amyloidosis (2 transthyretin-type/2 immunoglobulin light-chain-type). Voiding difficulties were due to detrusor weakness and impaired bladder sensation. In two patients cholinesterase inhibition treatment caused urge incontinence, indicating detrusor denervation supersensitivity. The underlying mechanisms of urinary dysfunction seem to involve postganglionic cholinergic and afferent somatic nerves.

Aged↗

Induction of epidermolysis bullosa acquisita in mice by passive transfer of autoantibodies from patients.

Epidermolysis bullosa acquisita (EBA) is an autoimmune sub-epidermal blistering disease characterized by autoantibodies to type VII (anchoring fibril) collagen. To date, however, direct evidence for a pathogenic role of human EBA autoantibodies has not been demonstrated. In this study, we affinity-purified anti-type VII collagen antibodies from EBA patients' sera and then injected them into adult hairless immunocompetent mice. Mice injected with EBA autoantibodies developed skin fragility, blisters, erosions, and nail loss on their paws - all features of EBA patients. By clinical, histological, immunological, and ultrastructural parameters, the induced lesions were reminiscent of human EBA. Histology showed bullous lesions with an epidermal-dermal separation. IgG and C3 deposits were observed at the epidermal-dermal junction. All mice had serum antibodies that labeled the dermal side of salt-split human skin like EBA sera. Direct immunogold electron microscopy specifically localized deposits of human IgG to anchoring fibrils. (Fab')(2) fragments generated from EBA autoantibodies did not induce disease. We conclude that EBA human patient autoantibodies cause sub-epidermal blisters and induce EBA skin lesions in mice. These passive transfer studies demonstrate that human EBA autoantibodies are pathogenic. This novel EBA mouse model can be used to further investigate EBA autoimmunity and to develop possible therapies.

Animals↗

Genetic and phenotypic diversity of quorum-sensing systems in clinical and environmental isolates of Vibrio cholerae.

Vibrio cholerae is the causative agent of cholera, a severe and devastating diarrheal disease. V. cholerae lives naturally in various aquatic habitats during interepidemic periods. Recent studies reveal that quorum-sensing systems, which exist in many bacteria and help them monitor their population densities and regulate various cellular functions, control V. cholerae pathogenesis, biofilm formation, and protease production. In this study we surveyed quorum-sensing systems in 16 geographically diverse V. cholerae strains from epidemic-causing O1 and O139 strains as well as non-O1/non-O139 and environmental isolates and discovered an unexpectedly high rate of dysfunctional components. We also found that a functional quorum-sensing system conferred a survival advantage on bacteria in biofilms when the bacteria were exposed to seawater, though quorum sensing was less important to survival in a planktonic state under the same conditions. These findings suggest that variations in quorum-sensing systems are due to environmental selective pressures and might be beneficial to V. cholerae's fitness under certain conditions found in its natural reservoirs.

Amino Acid Sequence↗

The transcriptional regulator VqmA increases expression of the quorum-sensing activator HapR in Vibrio cholerae.

Vibrio cholerae is the causative agent of the severe diarrheal disease cholera. A number of environmental stimuli regulate virulence gene expression in V. cholerae, including quorum-sensing signals. At high cell densities, quorum sensing in V. cholerae invokes a series of signal transduction pathways in order to activate the expression of the master regulator HapR, which then represses the virulence regulon and biofilm-related genes and activates protease production. In this study, we identified a transcriptional regulator, VqmA (VCA1078), that activates hapR expression at low cell densities. Under in vitro inducing conditions, constitutive expression of VqmA represses the virulence regulon in a HapR-dependent manner. VqmA increases hapR transcription as measured by the activity of the hapR-lacZ reporter, and it increases HapR production as measured by Western blotting. Using a heterogenous luxCDABE cosmid, we found that VqmA stimulates quorum-sensing regulation at lower cell densities and that this stimulation bypasses the known LuxO-small-RNA regulatory circuits. Furthermore, we showed that VqmA regulates hapR transcription directly by binding to its promoter region and that expression of vqmA is cell density dependent and autoregulated. The physiological role of VqmA is also discussed.

Gene Expression Regulation, Bacterial↗

Schistosoma japonicum: the design and experimental evaluation of a multivalent DNA vaccine.

The aim of this study was to construct and evaluate the immunity efficacy of the DNA multivalent vaccine pVIVO(2)SjFABP-23. The vaccine was constructed and produced as follows. Forty BALB/c mice were divided into four groups designated pVIVO(2), pVIVO(2)Sj23, pVIVO(2)SjFABP and pVIVO(2)SjFABP-23. Each mouse was immunized with 100 mug of the corresponding plasmid DNA by intramuscular injection. 28 days post-vaccination, the mice were challenged with S. japonicum cercariae, and the worm and egg burdens were determined 42 days post-challenge. Serum samples were collected from all the mice before and after vaccination and at the end of the experiment, and used for antibody detection. The IFN-gamma and IL-4 levels were quantified in the supernatants of specifically stimulated spleen cells. The number of worms was reduced by 52%, 40% and 42% in mice respectively immunized with pVIVO(2)SjFABP-23, pVIVO(2)Sj23 or pVIVO(2)SjFABP. A respective 61%, 38% and 39% egg reduction was determined relative to those mice that only received the empty pVIVO2 plasmid. pVIVO(2)SjFABP-23 immunization increased IgG levels against SWAP and SEA. Increased IFN-gamma levels were detected in the supernatant of specific stimulated spleen cells from mice immunized with the 3 different constructs. The multivalent DNA vaccine developed induced higher levels of protection than the two monovalent tested vaccines.

Animals↗

[FTIR spectroscopic studies of hydration effect on the molecular structure of polyether urethane].

The interaction between water molecules and the polar groups in linear polyether urethane was studied by FTIR and subtraction spectroscopy technique. Direct proofs of the combining of water molecule and carbonyl group were obtained. The reorganizations of the ether linkage, carbamate, and carbon-hydrogen chain after hydration were also observed. These results suggest that the FTIR and subtraction spectroscopy technique could be a useful tool to investigate the hydration mechanism of polymer materials.

English Abstract↗

[Structural study on the transparency of cross-linked polyester polyurethane].

The polyurethane material with cross-linked structure was synthesized using half pre-polymerization method. IR, UV-Vis, TEM and XRD methods, and physical properties measurements indicate that different moulding temperatures influence the apparent transparence of polyurethane and abrasive performance, and the nature of these changes is related to the conditions of processand chemical reaction which lead to gradual micro-phase separation of the polyurethane molecules with different compositions, resulting in the domain-forming with the size of sub-micro-, micro- and even more than ten micro-meters. Such domains aggregate one another to form particles with different shapes and complicated structures. The increase in the amount and size of these heterogeneous particles, distributed in the medium of transparent polyurethane, is the main cause that brings on an opaque appearance of polyurethane.

English Abstract↗

[Primary agiitis of central nervous system].

The common clinical manifestations of the primary agiitis of the central nervous system include burst of headache, dementia, change of aptitude, paralysis of cranial nerves, and recurrent focal depletion of the neural function. Lptomeningeal and brain biopsy are still the gold criteria for diagnosis. The prognosis may be improved after cortin and immunosuppressant therapy.

Humans↗

[Anteroposterior cricoid split interposition grafting for laryngotracheal stenosis in children].

OBJECTIVE: To investigate the effects of anteroposterior cricoid split interposition grafting on children with laryngotracheal stenosis. METHOD: This is a retrospective study, from 1991 to 2001 years, 12 children (aged 6 years to 15 years) with laryngotracheal stenosis were operated with cricoid split laryngotracheal reconstruction at our hospital. All of 12 patients were tracheostomy dependent before reconstruction. RESULT: Eleven patients (91.7%) were successfully decannulated with good airway patency and effective phonation. The follow-up period ranged from 1 to 10 years. The effect of operation is steady and the growth and development of children is normal. CONCLUSION: The anteroposterior cricoid split interposition grafting was a safe and effective method for treatment of laryngotracheal stenosis in children.

Adolescent↗

[Comparative analysis of ginsenosides from red ginseng].

OBJECTIVE: To determine ginsenoside Rg1, Re, Rb1, Rc, Rb2, Rd from main root and root hair of red ginseng of different specifications. METHOD: Ultrasonical extraction and reversed phase high performance liquid chromatography were applied. RESULT: The total contents of six ginsenosides from main root 15 roots (percent 500 g), 20 roots, 30 roots and root hair are 1.21%, 1.46%, 1.54% and 8.16%, respectively. CONCLUSION: The results showed that the bigger the volume of ginseng root, the less the content of ginsenoside.

Chromatography, High Pressure Liquid↗

[Quarter section cricoid split: its effect on cartilage growth in rabbits].

OBJECTIVE: To investigate the effect of the quarter-section cricoid split on cartilage growth. METHOD: The rabbits were killed 8 months after surgery of anterior, anteroposterior and quarter section cricoid split. The larynxes were harvested and the cross sectional areas of the cricoid cartilage were calculated. RESULT: There was no significant in the cross sectional area of the cricoid cartilage of any of the four groups. CONCLUSION: The quarter section cricoid split has no adverse effect on subsequent growth of cricoid cartilage and animals.

Animals↗

[Avian influenza (H5N1) cured successfully in human: a case report].

OBJECTIVE: To improve understanding of avian influenza in humans by presenting a case of avian influenza (H(5)N(1)). METHODS: Clinical and laboratory data of this case of avian influenza (H(5)N(1)) in humans were described, and related literature was reviewed. RESULTS: The female patient was 31 years old. She lived in epidemic district of avian influenza and had a history of close contact with sick poultry. The patient initially presented fever and chills accompanied by myalgia, and then followed by cough, blood-tinged sputum, dyspnea and frequent diarrhea. Laboratory findings indicated leukopenia, dysfunction of cellular immunity, abnormal enzymes of liver, and hypoxia. Patchy infiltration involved two lungs progressed rapidly on chest radiograph. ECG showed that T waves of V(1 - 5) were reverted. The patient was diagnosed with avian influenza (H(5)N(1)) by hemagglutination inhibition and microneutralization assay combined with epidemiological and clinical data. Supportive therapy, corticosteroids, antibacterial, and antiviral agents were administered. Complications were treated accordingly during the course. She got better overtime and recovered. The laboratory abnormalities and chest radiograph returned to normal before discharge. The patient's relatives and doctors involved in the medical care were free from infection. CONCLUSIONS: Supportive treatment is important for patients with avian influenza. Complications should be prevented and treated in time.

Adult↗