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Biomedical subjects

Z Zhou

Publications and source records attributed to Z Zhou.

At least 433 records · Page 24Linked to original sources
PubMed1995

[Clinical and pathological analysis of patients with hepatic metastases from colorectal cancer].

74 patients with colorectal cancer were divided into group A (34) with liver metastasis and group B (40) without by retrospective analysis. Based on the "Japanese General Rules for Clinical and Pathological Studies on Cancer of Colon, Rectum and Anus", the indicators of clinicopathological S, N, P, V, L, and inf were significantly different between the 2 groups (P < 0.01). But tumor size showed no significant difference between the 2 groups (P > 0.05). In the group A, cases of poorly differentiated carcinoma and medullary type carcinoma were more than those in the group B (P < 0.01).

Adenocarcinoma↗
PubMed1995

[Anti-metastasis gene nm23 expression in buccal cancer studied by immunohistochemistry stain].

The nm23 gene has been proposed as a candidate metastasis-suppressor gene. In this study we used immunohistochemistry stain for polyclone antibody nm23 in 62 cases of buccal carcinoma. The results showed that both the epithelium of mucosa and the duct epithelium of minor salivary gland nearby the tumor were strong positive. The stains on tumor cells were various. 31.0% (9/29) of the cases with lymph-node metastasis were positive while 57.6% (19/33) of those with no lymph-node metastasis positive (P = 0.044). Histologically, 59.4% (19/32) of the cases were positive in Grade I, while 37.5% (6/16) positive in Grade II and 21.4% (3/14) in Grade III (P = 0.048). The positive rate increased with the patients survival time from less than 3 years to 3-5 years and more than 5 years correspondingly, but there was no statistical significance (P = 0.126). The results suggested that the expression of nm23 might be one of the factors influencing the lymph-node metastasis and prognosis of buccal cancer.

Carcinoma, Squamous Cell↗
PubMed1995

[Determination of paracetmol caffeine and ephedrine hydrochloride in likeshu capsules].

Paracetamol (P), caffeine (C) and ephedrine hydrochloride (EH) are there physiological active component in Likeshu capsules. We have proposed the determination method of these three components using extractive separation-spectrophotometry. Only one amount weighed of sample is required to determine them. The recoveries of P, C and EH were 97.51 +/- 0.64% (n = 9), 98.24 +/- 1.04% (n = 8) and 98.58 +/- 1.09% (n = 9) respectively. The results of determination of samples agreed with those of the HPLC method. This method is sensitive, accurate and simple. The other ingredients of Likeshu capsules do not interfere.

Acetaminophen↗
PubMed1995

The changes of pattern reversal visual evoked potentials in normal infants.

PURPOSE: To study pattern reversal visual evoked potential (PVEPs) and determine the developmental character and mature time of visual function in normal infants at different months of age. METHODS: PVEPs were recorded from 115 normal infants at 3, 6, 9, 12 months age. P1 latency for different checks (1 degree 40', 25', 6') was analyzed and compared to those of normal adults. Changes of N1, N2 latency of PVEPs were also examined. RESULTS: P1 latency for all checks (1 degree 40', 25', 6') was significantly longer at 3 months than at 6 months of age (P < 0.05), but no significant differences can be seen after 6 months of age for larger (1 degree 40') and intermediate (25') checks (P > 0.05). P1 latency for larger checks (1 degree 40') reached adult level after 3 months of age, but not for the intermediate check (25'), while P1 latency for small check (6') presented the character of fluctuation. CONCLUSION: The visual system continued to develop after birth and appeared a certain regularity. Our results showed that P1 latency for larger check (1 degree 40') reached adult levels after 3 months of age. But P1 latency for intermediate check still has not reached adult levels after 3 months of age. To determine the age at which adult levels are finally reached, infants of 12 months and older must be tested. The reason why P1 latency for smaller check (6') presented the character of fluctuation should be the temporal tuning function developing much more slowly.

Child Development↗
PubMed1995

[Management of the dry eye with parotid duct transplantation: a summary on 40 cases].

PURPOSE: As today the effect of parotid duct transplantation is clinically regarded as uncertainty, and there is still absent of effective managenent of the dry eye, this paper tries to clarify its value, and see if it can be used clinically. METHODS: Forty dry eyes were operated with a follow up of 3 weeks to more than 6 years in the past 42 years. The pre- and postoperative changes of tear flow and vision, and the cause of dry eye, operative method, length of parotid duct and complications of bilateral operation were briefly summarized. RESULTS: Of these 40 operated eyes postoperatively, 82.5% had tearing, but no tearing occurred in 27.5%. Finally: vision increased in 72.5% with out any decrease. There was no difference in the results whether the procedure done extraorally or intraorally. The parotid duct being shorter was only seen in 7.5%, which were satisfactorily managed by tube making with oral mucosa. Four cases operated binocularly and silmutaneously, only 1 occurred aveolar abscess with complaining dry mouth, but cured 1 week later. After operation, profusive tearing occurred in 25 dry eyes caused by trachoma during eating and 96% usually, but tearing stopped finally in 3 eyes (2, due to infection). Four dry eyes with ocular pemphigoid failed. Among 9 dry eyes resulted from Stevens-Johnson syndrome, 6 had little tearing postoperatively, 2 of which attained a nearly normal results. One of the two dry eyes resulted from alkali eye burn failed and the other, occurred tearing but only followed-up for 1 month, the result was uncertain. CONCLUSION: As the technique of the parotid duct transplantation is simple and easy with no much complications, and for treating the dry eye, there is up to now still absent of effective management, therefore, the parotid duct transplantation should be considered to be indicated in dry eyes esp, caused by Stevens-Johnson syndrome. Though its success rate is lower than that of traucomatous ones, the satisfactory result of nearly normal postoperative tearing may be got. In ocular pemphigoid, however, it is contraindicated.

Follow-Up Studies↗
PubMed1994

Rapid turnover rate of the hippocampal synaptic NMDA-R1 receptor subunits.

The decrease in the number of synaptic NMDA receptors produced by prior i.c.v. injections of antisense oligonucleotides was examined in the CA1 stratum radiatum of hippocampal slices. Isolated NMDA and AMPA receptor-mediated components of extracellular synaptic responses were compared in slices obtained from control animals and from animals treated for 48 h with an 18-mer phosphorothioate antisense oligodeoxynucleotide directed against NMDA-R1. In slices ipsilateral to the injected hemisphere, the synaptic NMDA component was decreased by 29% compared with the contralateral side and by 34% compared with animals injected with vehicle alone. At the same time, synaptic AMPA receptor-mediated components were not affected. These results are consistent with a rapid turnover rate of synaptic NMDA-R1 and demonstrate the feasibility of antisense oligonucleotide techniques for the depletion of specific synaptic receptor channels.

Animals↗
PubMed1994

The SAD1/RAD53 protein kinase controls multiple checkpoints and DNA damage-induced transcription in yeast.

Inhibition of DNA synthesis prevents mitotic entry through the action of the S-phase checkpoint. We have isolated S-phase arrest-defective (sad) mutants that show lethality in the presence of the DNA synthesis inhibitor hydroxyurea (HU). Several of these mutants show phenotypes consistent with inappropriate mitotic entry in the presence of unreplicated DNA, indicating a defect in the S-phase checkpoint. sad1 mutants are additionally defective for the G1 and G2 DNA damage checkpoints, and for DNA damage-induced transcription of RNR2 and RNR3. The transcriptional response to DNA damage requires activation of the Dun1 protein kinase. Activation of Dun1 in response to replication blocks or DNA damage is blocked in sad1 mutants. The HU sensitivity of sad1 mutants is suppressed by mutations in CKS1, a subunit of the p34CDC28 kinase, further establishing a link between cell cycle progression and lethality. sad1 mutants are allelic to rad53, a radiation-sensitive mutant. SAD1 encodes an essential protein kinase. The observation that SAD1 controls three distinct checkpoints suggests a common mechanism for cell cycle arrest at these points. Together, these observations implicate protein phosphorylation in the cellular response to DNA damage and replication blocks.

Base Sequence↗
PubMed1994

A novel mutation in the cystic fibrosis gene in patients with pulmonary disease but normal sweat chloride concentrations.

BACKGROUND: Many patients with chronic pulmonary disease similar to that seen in cystic fibrosis have normal (or nondiagnostic) sweat chloride values. It has been difficult to make the diagnosis of cystic fibrosis in these patients because no associated mutation in the cystic fibrosis transmembrane conductance regulator (CFTR) gene has been identified. METHODS: We evaluated 23 patients with pulmonary disease characteristic of cystic fibrosis but with sweat chloride concentrations in the normal range. Mutations in the CFTR gene were sought by direct sequencing of polymerase chain reaction-amplified nasal epithelial messenger RNA and by testing the functioning of affected epithelium. RESULTS: A cytidine phosphate guanosine dinucleotide C-to-T point mutation in intron 19 of the CFTR gene, termed 3849 + 10 kb C to T, was identified in 13 patients from eight unrelated families. This mutation was found in patients from three different ethnic groups with three different extended haplotypes. The mutation leads to the creation of a partially active splice site in intron 19 and to the insertion into most CFTR transcripts of a new 84-base-pair "exon," containing an in-frame stop codon, between exons 19 and 20. Normally spliced transcripts were also detected at a level approximately 8 percent of that found in normal subjects. This mutation is associated with abnormal nasal epithelial and sweat acinar epithelial function. CONCLUSIONS: We have identified a point mutation in intron 19 of CFTR and abnormal epithelial function in patients who have cystic fibrosis-like lung disease but normal sweat chloride values. The identification of this mutation indicates that this syndrome is a form of cystic fibrosis. Screening for the mutation should prove diagnostically useful in this population of patients.

Adolescent↗
PubMed1994

Convergence of quantum electrodynamics in a curved modification of Minkowski space.

The interaction and total hamiltonians for quantum electrodynamics, in the interaction representation, are entirely regular self-adjoint operators in Hilbert space, in the universal covering manifold M of the conformal compactification of Minkowski space Mo. (M is conformally equivalent to the Einstein universe E, in which Mo may be canonically imbedded.) In a fixed Lorentz frame this may be expressed as convergence in a spherical space with suitable periodic boundary conditions in time. The traditional relativistic theory is the formal limit of the present variant as the space curvature vanishes.

Journal Article↗
PubMed1994

4-1BB T-cell antigen binds to mature B cells and macrophages, and costimulates anti-mu-primed splenic B cells.

4-1BB is expressed on activated murine T cells and may function as an accessory signaling molecule during T-cell activation. To identify putative 4-1BB ligands, a fusion protein consisting of the extracellular domain of 4-1BB fused to human placental alkaline phosphatase (4-1BB-AP) was constructed. Alkaline phosphatase activity could then be used as an indicator of the relative amount of bound 4-1BB. These studies indicated that 4-1BB-AP specifically bound to the surface of various mature B and macrophage cell lines. 4-1BB-AP bound at low levels to T cell lines (non-activated and anti-CD3-activated), pre-B-cell lines, and an immature macrophage cell line. 4-1BB-AP did not bind to a glial tumor cell line, HeLa cells, or COS cells. In addition, 4-1BB-AP bound at higher levels to F(ab')2 anti-mu-activated primary B cells compared to anti-CD3-activated primary T cells. Scatchard analysis indicated that the A20 B cell lymphoma expressed 3680 binding sites per cell with a Kd of 1.86 nM. Affinity cross-linking studies demonstrated that a major cell surface species of 120 kDa bound to 4-1BB-AP; 4-1BB-AP also bound to a minor species of approximately 60 kDa. The addition of paraformaldehyde-fixed SF21 cells expressing recombinant 4-1BB synergized with F(ab')2 anti-mu in inducing splenic B cell proliferation suggesting that 4-1BB may function as a regulator of B cell growth.

Animals↗
PubMed1994

Role of FGFs in skeletal muscle and limb development.

Fibroblast growth factors (FGFs) are a family of nine proteins that bind to three distinct types of cell surface molecules: (i) FGF receptor tyrosine kinases (FGFR-1 through FGFR-4); (ii) a cysteine-rich FGF receptor (CFR); and (iii) heparan sulfate proteoglycans (HSPGs). Signaling by FGFs requires participation of at least two of these receptors: the FGFRs and HSPGs form a signaling complex. The length and sulfation pattern of the heparan sulfate chain determines both the activity of the signaling complex and, in part, the ligand specificity for FGFR-1. Thus, the heparan sulfate proteoglycans are likely to play an essential role in signaling. We have recently identified a role for FGF in limb bud development in vivo. In the chick limb bud, ectopic expression of the 18 kDa form of FGF-2 or FGF-2 fused to an artificial signal peptide at its amino terminus causes skeletal duplications. These data, and the observations that FGF-2 is localized to the subjacent mesoderm and the apical ectodermal ridge in the early developing limb, suggest that FGF-2 plays an important role in limb outgrowth. We propose that FGF-2 is an apical ectodermal ridge-derived factor that participates in limb outgrowth and patterning.

Animals↗
PubMed1994

T-type calcium current in latent pacemaker cells isolated from cat right atrium.

Whole-cell voltage clamp techniques were used to study Ca2+ currents in latent pacemaker cells isolated from cat right atrium. T-type (ICa,T) and L-type (ICa.L) Ca2+ currents were distinguished by their voltage dependence of activation, and sensitivity to channel blocking agents. In 2.7 mM [Ca]o, ICa,T activation exhibited a voltage threshold of about -50mV and maximum amplitude at -10mV, whereas ICa,L threshold was about -30mV and maximum amplitude was at +10mV. The half-maximal activation voltages of ICa,T was -31.4 +/- 0.2mV and ICa,L was -6.2 +/- 2.0mV. Overlap of the steady-state activation-inactivation curves for ICa,T showed a "window" current at voltages compatible with the late phase of diastolic depolarization. Maximum ICa,T and ICa,L current densities were 3.3 +/- 0.4pA/pF and 12.5 +/- 1.3pA/pF, respectively. ICa,T current density in working atrial muscle cells was 0.73 +/- 0.31pA/pF. Both ICa,L and ICa,T were blocked by 2mM cobalt. ICa,L but not ICa,T was blocked by 1 microM nifedipine. Nickel (Ni2+; 40 microM) inhibited ICa,T primarily at more negative voltages. In addition, Ni2+ decreased the late phase of diastolic depolarization and significantly increased pacemaker cycle length. These results indicate that latent atrial pacemaker cells exhibit ICa,T that is significantly larger in amplitude than in working atrial muscle cells. ICa,T may contribute current during the late phase of diastolic depolarization. Because latent pacemakers exhibit a more negative maximum diastolic potential, ICa,T may contribute more to latent than to primary pacemaker activity.

Animals↗
PubMed1994

Delayed rectifier potassium current (IK) in latent atrial pacemaker cells isolated from cat right atrium.

Whole-cell recording techniques were used to study the delayed rectifier K+ current (IK) in latent pacemaker cells isolated from cat right atrium. From a holding potential of -40 mV, depolarizing clamp steps elicited L-type Ca2+ current followed by an increasing outward current (IK). The time course of tail current amplitudes paralleled that of the time-dependent activation of outward current. Activation of IK exhibited a sigmoidal time course that was best fit by a power function where the activation variable was raised to the second power. The voltage-dependence of IK activation exhibited a sigmoidal relationship between -40 and +30 mV. The half-maximal activation voltage and slope factor were -21.9 +/- 1.3 and 13.8 +/- 0.9 mV respectively (n = 6). The fully activated I/V relationship of IK was linear between -100 and -30 mV and inwardly rectified at more positive voltages. Following IK activation, hyperpolarizations more negative than about -50 mV elicited tail currents that consisted of both IK deactivation and I(f) activation. A subtraction protocol was used to isolate IK tail currents. In 5.4 mM extracellular [K+], IK tail currents exhibited a reversal potential of -78.2 +/- 0.3 mV (n = 6). The reversal potential of IK was linearly related to log extracellular [K] and the slope was 51.5 mV per ten-fold change in extracellular [K]. At -70 mV, IK tail currents decayed as a single exponential function with a time constant of 159 +/- 16 ms (n = 6). These results indicate that latent atrial pacemakers exhibit IK activated by depolarization.(ABSTRACT TRUNCATED AT 250 WORDS)

Action Potentials↗
PubMed1994

In vitro femoral arterial responses to vasoconstrictor and vasodilator agents in endotoxin shock.

The hypothesis for this study is that the decreased arterial response to catecholamines may be due to the effect of endotoxemia on vessel tone. One control ring was taken from one femoral artery of a Wistar rat and after endotoxin (ENDT) infusion (i.v. 6 mg/kg-1 hr.), one ring was removed from the contralateral artery. The post-ENDT rings were tested in four groups which were determined by the mean arterial pressure (MAP) levels at the time of dissection: 100 mmHg (120 min), 80 mmHg (270 min), 60 mmHg (300 min) or 40 mmHg (330 min). KCl, phenylephrine (PHE) and arginine-vasopressin (AVP) dose-response curves (DR) were obtained at a preload of 500 mg which allowed the maximum response in control rings. When compared at 500 mg preload the maximal active response to all agonists post-ENDT was decreased by about 50%. By increasing the preload on the ENDT rings to 800 mg, the active tension became 2.49 times the active tension of the control rings. Length-tension experiments also showed a greater response for post-ENDT rings and a greater preload at maximum response but the ring circumference was the same. In contrast the in vivo femoral artery diameters at 90 min post-ENDT (100 mmHg) were 82.6% of control. Endothelium-dependent relaxation by acetylcholine (ACh) was abolished by ENDT but endothelium-independent relaxation to nitroprusside (NP) was not affected. It is concluded that the resting tone and active tension of femoral artery smooth muscle is increased by ENDT and the decreased in vivo responsiveness to vasoconstrictor agonists may be the result of vessel constriction due to loss of endothelium. The results also suggest that in vitro comparison of vessels in studies of endotoxin shock be done at the same muscle length rather than at the same preload.

Acetylcholine↗
PubMed1994

Translocation (8;21) in oligoblastic leukemia: is this a true myelodysplastic syndrome?

An 8;21 translocation with trisomy 4 is described in a 36-year-old Chinese woman who presented with an oligoblastic leukemia with myelodysplastic (MDS) features. Progression to acute myeloblastic leukemia (AML) occurred 3 months after presentation. She died of septicemia without remission. Through a review of the data in 10 cases of oligoblastic leukemia with t(8;21) in the literature, we make the following comments. (i) Oligoblastic leukemia with t(8;21) represents 2-3% of cases with this karyotype. (ii) Such cases behave in a similar manner to de novo AML. (iii) The presence of features of MDS has no affect on the behaviour of the disease. (iv) Such cases should be treated without delay with intensive chemotherapy.

Adult↗
PubMed1994

Mn2+ as a contrast reagent for NMR studies of 35Cl- and 81Br- transport through model biological membranes.

One major problem in using NMR to study halide ions in biological and model biological systems has been to find a contrast reagent to differentiate between halide ions in different compartments. Mn2+ is shown to be a very efficient NMR relaxation agent for the halide ions chloride and bromide and preferable to Co2+ at high magnetic fields. Its use is demonstrated in experiments in which halide ions are exchanged across the membranes of egg yolk phosphatidylcholine vesicles by the phase transfer catalysts tetrabutylammonium ion and benzyltributylammonium ion. Benzyltributylammonium ion is shown to be the more rapid anion transporter through the membrane. Valinomycin is found to cotransport ammonium ions with chloride as an ion pair at a faster rate than the phase transfer catalysts.

Biological Transport↗