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Biomedical subjects

Z H Zhang

Publications and source records attributed to Z H Zhang.

At least 19 recordsLinked to original sources
PubMed2006

Renal replacement lipomatosis.

We report a relatively rare case of renal replacement lipomatosis presenting as a renal mass. Computed tomography revealed a predominantly low-density and roundish mass, with an irregular renal parenchyma, high-density calcification, and abundant low-density fat. The differential diagnosis before surgery was squamous cell carcinoma, teratoma, or angiomyolipoma of the kidney. The case was initially misdiagnosed, because we had no experience with this disease. After mass exploration, histological examination confirmed the diagnosis of renal replacement lipomatosis. The patient was free from signs of recurrence 10 months after the operation.

Female↗
PubMed2005

A mutation in SART3 gene in a Chinese pedigree with disseminated superficial actinic porokeratosis.

BACKGROUND: Disseminated superficial actinic porokeratosis (DSAP) is an uncommon autosomal dominant chronic disorder of keratinization, characterized by multiple superficial keratotic lesions surrounded by a slightly raised keratotic border. Thus far, although two loci for DSAP have been identified, and the genetic basis and pathogenesis of this disorder have not been elucidated. OBJECTIVES: To determine the locus of DSAP and identify the candidate gene(s) of the disease. METHODS: Genome-wide scan and linkage analysis were performed in a six-generation Chinese family with DSAP. The coding exons of the candidate genes were sequenced to analyse and detect the nucleotide variations. RESULTS: Linkage analysis showed that the maximum two-point lod score of 5.56 was obtained with the marker D12S79 at a recombination fraction theta of 0.00. Haplotype analysis defined the critical region for DSAP between D12S330 and D12S1612 on 12q24.1-24.2. By sequence analysis, we found a Val591Met mutation in SART3 in all affected individuals of the family. CONCLUSION: SART3 is a candidate gene for DSAP, and is possibly involved in the pathogenesis of DSAP.

Antigens, Neoplasm↗
PubMed2005

Congenital facial linear porokeratosis.

We report a unique case of congenital linear porokeratosis with exclusive facial involvement in a 27-year-old Chinese man. No other family member was affected. To our knowledge, this is the first report in the English literature of congenital linear porokeratosis confined to the face.

Adult↗
PubMed2004

Association of variations in monoamine oxidases A and B with Parkinson's disease subgroups.

Idiopathic Parkinson's disease (PD) is an age dependent, neurodegenerative disorder and is predominantly a sporadic disease. A minority of patients has a positive family history for PD and the majority of those families exhibit a complex mode of inheritance. The monoamine oxidases A and B (MAO-A and -B) genes, which are involved in serotonin and dopamine metabolism, are possible candidate genes for susceptibility to PD. Previous association studies of MAO-A and -B in PD have been inconclusive. To determine the role of MAO-A and -B in the development of PD, we screened a sample of 96 patients with familial PD, 164 with sporadic PD, and 180 matched normal controls with dinucleotide repeat markers in these genes. MAO-A and -B gene polymorphisms were strongly associated with total PD (p < 0.00001), familial PD (p < 0.00001), and sporadic PD (p < 0.00001). There were no significant differences between familial or sporadic PD with age of onset younger than 50 years compared to those with age of onset older than 51 years for both MAO-A and -B genes. There was no linkage disequilibrium between these genes in male PD and control groups. The frequency of common haplotypes from MAO-A and -B was different in PD and control group (p = 0.02). Our data indicate that MAO-A and -B may play a role in susceptibility to PD in our sample.

Age of Onset↗
PubMed2003

Metabolism-enhanced tumor localization by fluorescence imaging: in vivo animal studies.

We present a high-sensitivity near-infrared optical imaging system for noninvasive cancer detection and localization based on molecularly labeled fluorescent contrast agents. This frequency-domain system utilizes the interferencelike pattern of diffuse photon density waves to achieve high detection sensitivity and localization accuracy for the fluorescent heterogeneity embedded inside the scattering media. A two-dimensional localization map is obtained through reflectance probe geometry and goniometric reconstruction. In vivo measurements with a tumor-bearing mouse model by use of the novel Cypate-mono-2-deoxy-glucose fluorescent contrast agent, which targets the enhanced tumor glycolysis, demonstrate the feasibility of detection of a 2-cm-deep subsurface tumor in the tissuelike medium, with a localization accuracy within 2-3 mm.

Animals↗
PubMed2003

Lichens as biomonitors of uranium in the Balkan area.

The contribution of the conflict of 1999 to the environmental levels of uranium in the Balkan area was evaluated by means of lichens used as biomonitors. The average U concentration found in lichens in the present study was in line with the values reported for lichens from other countries and well below the levels found in lichens collected in areas with natural or anthropogenic sources of U. Measurement of isotopic ratios 235U/238U allowed to exclude the presence of depleted uranium. According to these results, we could not detect widespread environmental contamination by depleted uranium in the Balkan area.

Environmental Monitoring↗
PubMed2001

[Prolactin in normal pregnancy and severe pregnancy-induced hypertension].

OBJECTIVE: This study was to investigate the relationship between serum prolactin and pregnancy-induced hypertension. METHOD: Maternal serum prolactin was estimated by radioimmunoassay in 89 normal pregnant women and 52 patients with severe pregnancy-induced hypertension at 28 to 42 week gestation. RESULTS: In normal pregnancy, prolactin level increased progressively from a mean value of 270 mg.L-1 in the 24th week to 440 mg.L-1 in the 34th week and decreased progressively from the 38th week to the 40th week. In severe pregnancy-induced hypertension increased progressively too; 31 of 52 patients with severe prolactin showed high prolactin levels in zone A (> mean value + standard of prolactin values in the normal pregnancy), 10 patients in zone B (mean + standard to mean) and 11 patients in zone C (< mean). CONCLUSION: These results suggest that high prolactin levels may play an important role in the pathogenesis of severe pregnancy-induced hypertension.

Adult↗
PubMed2001

Melatonin and its analogs potentiate the nifedipine-sensitive high-voltage-activated calcium current in the chick embryonic heart cells.

Effects of melatonin and its analogs on the voltage-activated calcium current of embryonic chick ventricular cardiomyocytes were investigated. Myocytes were dissociated from 14- to 16-day-old chicks (yellow Red Rob) embryonic hearts and cultured for 2 3 days. Calcium currents were studied by the patch-clamp technique. Whole-cell current recording showed nifedipine-sensitive, high-voltage-activated L-type calcium current inactivated in 70-100 ms during the voltage step period of 200 ms. There was no evidence of low-voltage-activated T-type calcium channels. Melatonin (ejected solution: 50 micromol/L melatonin; concentration at the vicinity of recording cell: about 1-5 micromol/L melatonin) and its analogs, 2-iodomelatonin and 2-iodo-n-butanol-5-methoxytryptamine, significantly increased the amplitude of the calcium current by 42-62%. The effect of melatonin on the L-type calcium current was not desensitised by repeated melatonin treatment. Our results suggest a specific melatonin receptor-mediated action on the calcium channel of the embryonic chick myocyte. The melatonin-induced increase in high-voltage calcium current may increase myocyte contractility and enhance cardiac output. A regulatory role of melatonin on the chick cardiac function should be further considered.

Animals↗
PubMed2001

Neurohumoral regulation in ischemia-induced heart failure. Role of the forebrain.

Congestive heart failure (CHF) is characterized by neurohumoral excitation. Increased sympathetic drive and activation of the reninangiotensin-aldosterone system (RAAS), with vasoconstriction and volume retention, are hallmarks of the CHF syndrome. Treatment strategies have targeted the peripheral influences of these two systems, but have not addressed the central mechanisms that drive them. We monitored the development of CHF following coronary ligation in adult Sprague-Dawley rats. Left ventricular dysfunction characteristic of CHF was confirmed by echocardiography, and the CHF syndrome was validated by measurements of circulating hormones, sodium appetite, thirst, renal sodium and water retention, and renal sympathetic nerve activity (RSNA). In CHF rats, neuronal activity in the hypothalamic paraventricular nucleus (PVN), which mediates downstream effects of forebrain circumventricular organs, was increased and was inhibited by blocking components of the RAAS at the forebrain level. Forebrain (AV3V) lesions and intracarotid (forebrain directed) injections of agents (captopril, losartan, spironolactone) that block RAAS substantially attenuated the behavioral and physiological manifestations of CHF. Intravenous losartan and captopril, in doses that lower arterial pressure, increased RSNA. These findings demonstrate an important role for RAAS-activated forebrain mechanisms in CHF and suggest that the central neural mechanisms driving sympathetic nerve activity and volume retention may persist and promote the progression of CHF despite treatments directed toward the peripheral influences of RAAS.

Animals↗
PubMed2001

[Study on the genetic variations of the major neutralization antigen VP7 of group A rotavirus type G1 in China].

OBJECTIVE: To study the genetic variations of the major neutralization antigen VP7 of group A rotavirus, type G1 in China. METHODS: Twenty-three isolates derived from seven cities (Beijing, Shenyang, Xinxiang, Shanghai, Shenzhen, Guangzhou and Chongqing) during the period of 1988-1998 were analyzed for the VP7 cDNA sequences. RESULTS: An obvious homology was observed in amino acid sequences of VP7 in the 23 isolates. Compared with the standard strain Wa, the variations were found at the position of aa 41, 49, 57, 65, 68, 74, 94, 97, 147, 170, 217, 218, 268, 281 and 291, respectively, and all of these were located in the variable region(VR)3,4,5,7,8 as well as in the C-terminal of the peptide. There seemed to be no remarkable divergence among the samples collected from different cities and all of them shared the same genetic lineage with the strain Jpn-417, though there might be one or two amino acid substitutions as time passed. When detected simultaneously with ELISA using G1 serotype-specific monoclonal antibody, the location of amino acid 91 was found presumably related to the neutralization epitope in VP7 of the type G1. Variations at some position may be resulted in the change of electropherotype. CONCLUSIONS: The results indicated that the recent isolates with representative genetic and antigenic features should be used to develop effective vaccines, and the antigenic variations should be monitored periodically.

Amino Acid Sequence↗
PubMed2001

[Determination of naoning pian by multi-wavelength linear regression method].

Assay of naoning pian was reported by multi-wavelength linear regression method in this paper. The program was edited by BASIC. The recoveries and RSD of pyramidon and caffeine were 98.03%-100.9%, 1.0% and 97.77%-99.39%, 0.61%, respectively. This method could be used for the determination of two components in naoning pian without separation. The method was simple, rapid, and results were satisfactory.

Analgesics, Non-Narcotic↗
PubMed2000

4-aminopyridine, a specific blocker of K(+) channels, inhibited inward Na(+) current in rat cerebellar granule cells.

The effects of 4-aminopyridine (4-AP), a specific blocker of outward K(+) current, on voltage-activated transient outward K(+) current (I(K(A))) and inward Na(+) current (I(Na)) were investigated on cultured rat cerebellar granule cells using the whole cell voltage-clamp technique. At the concentration of 1-5 mM, 4-AP inhibited both I(K(A)) and I(Na). It reduced the amplitude of peak Na(+) current without significant alteration of the steady-state activation and inactivation properties. The inhibitory effect was not enhanced by repeated depolarizing pulses (0.5 or 0.1 Hz), suggesting that the binding affinity of 4-AP on Na(+) channels is state-independent. In contrast, the effect of 4-AP on Na(+) channels appeared to be voltage-dependent, the weaker inhibition occurred at more depolarization. Moreover, 4-AP slowed both the activation and inactivation kinetics of Na(+) current. These effects were similar to those induced by alpha-scorpion toxin and sea anemone toxins on Na(+) channels in other cell model. Our data demonstrate for the first time that 4-AP is able to block not only A-type K(+) channels, but also Na(+) channels in rat cerebellar granule cells. It is concluded that the inhibition exerted by 4-AP on Na(+) current likely differs from that provoked by local anesthetics. The possibility that the binding site of neurotoxin receptor 3 may be involved is discussed.

4-Aminopyridine↗
PubMed2000

Functional variant in the DRD2 receptor promoter region and subtypes of alcoholism.

Dopaminergic pathway genes are considered as candidate genes for several neuropsychiatric diseases including severe alcoholism. Since 1990, there have been numerous reports of conflicting association studies of the Taq I A allele of the dopamine D2 receptor (DRD2) gene and alcoholism. Functional and structural variations in candidate genes offer more direct evaluation of their role in the development of a disorder. To determine the role of such variations in the DRD2 gene in the development of alcoholism subtypes, we screened a sample of 173 alcoholics and 88 normal controls with the A-241G and -141C Ins/Del variations in the promoter region and C311G variation in exon 7 of the DRD2 gene. Comparison of alcoholics with normal controls for allele frequency differences of these three variations was negative. Allele frequency differences of the two variations in the promoter region between type II alcoholics, alcoholics with medical complications, and normal controls were not significant. There was linkage disequilibrium only between -141 Ins/Del and Taq I D polymorphisms. We conclude that the functional and structural variations in DRD2 gene do not play a major role in the development of alcoholism subtypes in our sample.

Alcoholism↗
PubMed2000

The abnormality of glucose transporter in the erythrocyte membrane of Chinese type 2 diabetic patients.

Type 2 diabetes mellitus is characterized by impaired glucose uptake. With a photometric method of recording the erythrocyte suspension absorption during the course of glucose transport across the membranes, we observed that the initial rate of glucose zero-trans entry was decreased significantly in 30 Chinese type 2 diabetic patients as compared to 25 healthy controls. The rate of glucose infinite-cis efflux exhibited no difference between the patients and controls. The measurement of temperature dependence of glucose transport showed that the activation energy for glucose entry was increased in diabetic patients. The inhibitory constant of glucose entry by cytochalasin B (CB) in patients was similar to that of the controls. However, we found that the inhibitory constant was increased significantly in the patient erythrocytes after phloretin treatment. After the erythrocytes were made into stripped white ghosts, the fluorescence quenching experiment was performed. Glucose, CB and phloretin can quench the fluorescence of tryptophan residues in the glucose transporter 1, GLUT1. The abnormality of fluorescence quenching in the erythrocyte membranes of patients was observed. The transfer tendency of tryptophan residues from the hydrophilic environment to the hydrophobic environment was decreased in patient ghosts as binding with glucose, and the opposite tendency appeared as CB and phloretin instead of glucose. We conclude that the decreased in glucose entry in the erythrocyte membranes of diabetic patients was due to the GLUT1 change in structure - mostly the outer domain of the glucose transporter.

Asian People↗
PubMed2000

Baroreceptive and somatosensory convergent thalamic neurons project to the posterior insular cortex in the rat.

Connectivity between the rat posterior insula and the ventrobasal thalamus has been demonstrated anatomically. Neurons convergent for baroreceptor and nociceptive input have also been identified in the homologous anterior insula of the primate. Whether similar convergent cells exist in the ventrobasal thalamus was investigated in 30 urethane anesthetized male Sprague--Dawley rats. Six classes of cells were identified in the right ventrobasal thalamus: (a) 83/159 (52%) baroreceptive and nociceptive convergent units; (b) 2/159 (1%) convergent cells responding to baroreceptor activation and light touch; (c) 44/159 (28%) purely nociceptive units; (d)10/159 (6%) purely baroreceptive units; (e) 1/159 (0.6%) cells responding to brush alone and (f) 19/159 (12%) unresponsive units. Of the viscerosomatic convergent cells, 66/85 (78%) were situated in the ventroposterolateral nucleus (VPL), 6/85 (7%) in the ventroposterolateral parvicellular nucleus (VPLpc), and 13/85 (15%) in the ventroposteromedial nucleus (VPM). Fifteen right ventrobasal thalamic units were antidromically activated and 34 units orthodromically activated by right posterior insular microstimulation. Cobalt injection into the right ventrobasal thalamus blocked the right insular response to baroreceptor activation by >70%. These data indicate: (a) baroreceptive and somatosensory nociceptive convergent units exist in the ventrobasal thalamus; (b) thalamic convergent neurons project directly to the ipsilateral posterior insula and receive reciprocal insulothalamic projections; and (c) a significant proportion of baroreceptor input relays to the posterior insula through the ipsilateral ventrobasal thalamus.

Animals↗
PubMed2000

Modulation of a cloned human A-type voltage-gated potassium channel (hKv1.4) by the protein tyrosine kinase inhibitor genistein.

A cloned, human, A-type, voltage-gated potassium channel (hKv1.4) was expressed transiently in Chinese hamster ovary cells and the effects of the broad-spectrum tyrosine kinase inhibitor genistein on hKv1.4 were studied using the whole-cell patch-clamp recording method. Genistein (up to 50 microM) reversibly reduced the peak currents of hKv1.4 by 44.9+/-12%. In addition, genistein markedly slowed the activation kinetics (time constant tau(a)) of hKv1.4. At +50 mV, tau(a) increased from 1.8+/-0.3 to 5.0+/-0.6 ms (P<0.01). The effect of genistein on the channel inactivation kinetics (time constant tau(i)) was more complex, in that tau(i) was increased significantly at lower step potentials but unaltered at +50 mV or more depolarized potentials. Tail current analysis showed that genistein had no effect on the kinetics of deactivation (time constant tau(d)), but shifted the steady-state activation curve significantly to the right by about 15 mV (potential for half-maximal activation, V1/2, changed from -7.4+/-4.4 to +7.7+/-2.7 mV) with a moderate change in the slope (k) of the curve (from 17.4+/-2.2 to 23+/-1.0 mV, P<0.05). Genistein slightly altered the slope of the steady-state inactivation curve from -5.5+/-0.4 to -7.5+/-0.4 mV (P<0.01). The recovery rate from inactivation was not altered by genistein. The tyrosine phosphatase inhibitor orthovanadate (1 mM) alone had little impact on current amplitude or channel kinetics. However, orthovanadate significantly, but not completely, blocked the effect of genistein on current amplitude (by 25.5%) and kinetics (by 67.1%). Daidzein (up to 50 microM), an inactive analogue of genistein, had no effect on current amplitude or kinetics. In contrast to genistein, another tyrosine kinase inhibitor, herbimycin A, had little effect on the channel peak amplitude or kinetics. In addition, genistein had a similar impact on the channel peak current amplitude and kinetics in cells with or without pre-treatment with herbimycin A (10 microM). The data suggest that genistein-induced inhibition of tyrosine phosphorylation may not be the exclusive mechanism by which hKv1.4 is down-regulated and channel gating affected. Genistein may produce a non-catalytic blockade of this channel.

Animals↗