Biomedical subjects

Zhen Jin

Publications and source records attributed to Zhen Jin.

34 records · Page 2Linked to original sources

PubMed2005

[The biochemical changes of hippocampus in patients before and after denture restoration: a preliminary 1H-magnetic resonance spectroscopy study].

OBJECTIVE: To study the effects of reconstruction of lost occlusal support on the biochemical changes of nervous system. METHODS: The changes of central nervous system metabolic compounds within hippocampus body were measured with proton magnetic resonance spectroscopy ((1)HMRS) before and after denture restoration (six weeks) in seven patients with prolonged loss of occlusal support. RESULTS: (1)HMRS indicated that Cho/Cr decreased by 11.9% (P < 0.05) six weeks after denture restoration, MI/Cr decreased by 28.8% (P < 0.05), and NAA/CR increased by 4.8% (P > 0.05) within hippocampus body. CONCLUSIONS: Recovery of occlusal support facilitates improvement of neuron functions in patients' hippocampus, which may help improve the functions of nervous system.

Aged↗

PubMed2005

[Neuronal activities related to right-sided mastication detected with functional magnetic resonance imaging].

OBJECTIVE: To observe neuronal activities related to right-sided mastication in cortex and to explore the effect of mastication on brain function. METHODS: Neuronal activities related to right-sided mastication were detected with functional magnetic resonance imaging in 10 healthy volunteers. Image data was analyzed by SPM99 software with the use of t test. RESULTS: Localization of activation in brain was different among subjects. Brain activation during mastication included left basal ganglion, Broca's area, angular gyrus and right supramarginal gyrus. CONCLUSIONS: The functional areas related to right-sided mastication and speech were closely connected, which indicated close relationship between mastication and speech. The central control of mastication might share part of common neural mechanism with that of speech. The roles of activated brain regions in mastication still remained to be elucidated.

Adult↗

PubMed2004

Biological abnormality of impaired reading is constrained by culture.

Developmental dyslexia is characterized by a severe reading problem in people who have normal intelligence and schooling. Impaired reading of alphabetic scripts is associated with dysfunction of left temporoparietal brain regions. These regions perform phonemic analysis and conversion of written symbols to phonological units of speech (grapheme-to-phoneme conversion); two central cognitive processes that mediate reading acquisition. Furthermore, it has been assumed that, in contrast to cultural diversities, dyslexia in different languages has a universal biological origin. Here we show using functional magnetic resonance imaging with reading-impaired Chinese children and associated controls, that functional disruption of the left middle frontal gyrus is associated with impaired reading of the Chinese language (a logographic rather than alphabetic writing system). Reading impairment in Chinese is manifested by two deficits: one relating to the conversion of graphic form (orthography) to syllable, and the other concerning orthography-to-semantics mapping. Both of these processes are critically mediated by the left middle frontal gyrus, which functions as a centre for fluent Chinese reading that coordinates and integrates various information about written characters in verbal and spatial working memory. This finding provides an insight into the fundamental pathophysiology of dyslexia by suggesting that rather than having a universal origin, the biological abnormality of impaired reading is dependent on culture.

Asian People↗

PubMed2004

An fMRI study with semantic access in low proficiency second language learners.

Brain activity was measured with fMRI in twelve 10- to 12-year-old Chinese children who began learning English when they were 8 years old in order to find out whether there is a common or a distinct neural semantic system for native language (L1) and second language (L2) in low proficiency bilingual subjects. Although they performed less well in L2 in the semantic decision task administered during fMRI measurement, these subjects showed similar robust activation, for both languages, in brain areas involved in semantic processing (e.g. the left inferior frontal cortex). Within-subject and group analyses revealed no significant difference in the activation patterns for L1 and L2 in these regions. These results suggest that at least at single-word level, there are shared neural substrates for semantic processing of L1 and L2 even when one is at a very low L2 proficiency level.

Brain↗

PubMed2004

Evidence from brain imaging with fMRI supporting functional specificity of acupoints in humans.

We tested whether the stimulation of acupoints in the same spinal segments could induce different central responses with functional magnetic resonance imaging (fMRI) study. Stimulation of acupoints ST36/SP6 (Zusanli/Sanyinjiao) or GB34/BL57 (Yanglingquan/Chengshan) both activated primary and secondary somatosensory area, insula, ventral thalamus, parietal Brodmann Area 40, temporal lobe, putamen, and cerebellum, while de-activated amygdala. Nevertheless, ST36/SP6 stimulation specifically activated orbital frontal cortex and de-activated hippocampus. Alternatively, stimulation of GB34/BL57 activated dorsal thalamus and inhibited those of primary motor area and premotor cortex. Thus, stimulation of acupoints in the same spinal segments induced distinct though overlapped cerebral response patterns, which indicated the existence of acupoint specificity.

Adult↗

PubMed2004

fMRI evidence for the automatic phonological activation of briefly presented words.

Functional magnetic resonance imaging was used to investigate whether people generate the phonology of briefly presented words that they do not attend. This was done in Chinese by examining the effect of orthography-phonology regularity (i.e., how predictable the phonology of a word is from its components rather than whole-word form) with high- and low-frequency words, and by using a task that diverted participants' attention to a mask, rather than the words. The results showed that there was a significant interaction between regularity and word frequency in blood oxygen level-dependent (BOLD) signal, which mirrored the pattern found in behavioral data. Specifically, for low-frequency characters, bilateral fusiform gyri, the posterior superior temporal gyrus, and inferior parietal regions were more active when using irregular compared to regular characters. There were no significant differences when high-frequency characters were used. These results support the possibility that at least for low-frequency words, phonology is automatically generated when reading, even when people do not attend to the words and even in a language where the orthography-phonology mapping is extremely irregular.

Adolescent↗

PubMed2004

Emotional valence of words modulates the subliminal repetition priming effect in the left fusiform gyrus: an event-related fMRI study.

The present study investigated if the emotional valence of words modulates the subliminal repetition priming effect in the brain, in particular, the occipitotemporal visual cortex, by adopting a rapid presentation event-related fMRI design. A masked repetition priming paradigm was adopted, in which, before the presentation of the target (either positive or negative or neutral in meaning), a masked prime word that was either a repetition or an unrelated word of the target was presented. The subject made a perceptual judgment on the target. The results revealed that the left mid-fusiform gyrus was sensitive to the emotional manipulation of the repetition priming effect and that the priming effect in the region was greater in the positive than in the negative word condition. The priming effect in the fusiform gyrus in neutral words was not significant, which might be a result of suppression caused by the emotional context. No effect of valence or repetition was found in the amygdala.

Adolescent↗

PubMed2004

Neural representations of nouns and verbs in Chinese: an fMRI study.

The neural representation of nouns and verbs has been a focus of many recent neuroimaging and neuropsychological studies. These studies have in general found that in English and other Indo-European languages, verbs are represented in the frontal region (e.g., the left prefrontal cortex) while nouns in the posterior regions (the temporal-occipital regions). There is accumulating evidence, however, that the picture may have been overly simplified. In the present study, we examine the representations of nouns and verbs in Chinese, a language that has unique properties in its grammar and particularly in the structure of nouns and verbs. In an fMRI experiment, subjects viewed a list of disyllabic nouns, verbs, and class-ambiguous words and performed a lexical decision on the target. Results from the experiment indicate that nouns and verbs in Chinese activate a wide range of overlapping brain areas in distributed networks, in both the left and the right hemispheres. The results provide support for the prediction regarding the impact of linguistic typology and language-specific influences on the neural representation of grammatical categories. They are consistent with recent proposals that specific linguistic experience shapes neural systems of reading and speaking and that the language-specific properties of the Chinese grammar affect the representation, processing, and acquisition in this language.

Adult↗

PubMed2004

Mapping of verbal working memory in nonfluent Chinese-English bilinguals with functional MRI.

Existing cognitive and neural imaging studies have suggested a frontoparietal network of multiple, cooperative components for verbal working memory (WM). We used functional MRI to investigate whether this neural network is also involved in the processing of second language by nonfluent bilinguals. Twelve (five males, seven females) native Chinese speakers who had limited English proficiency were scanned while performing working memory tasks in Chinese and English. They were asked to make judgment continuously whether the word presented on the screen was semantically related to (i.e., the semantic tasks) another word presented two words earlier. On a different task (i.e., the phonological tasks), they were asked to make judgment whether the target word rhymed with the other word. A naming and judgment task in each language was adopted to control for the visual process, initial lexical process, and motor responses. Behavioral data showed that subjects performed better at tasks in their native language (Chinese, L1) than in English (L2). Imaging results showed that all working memory tasks in both L1 and L2 elicited a very similar pattern of left-hemisphere-dominated activation in the dorsolateral prefrontal cortex, pars opercularis region, pars triangularis region, precentral cortex, and parietal lobule. Consistent with the behavioral data, the volume of activation in the left opercularis region, left parietal lobule, and right precentral region was greater for L2 than for L1. These results suggest that working memory in L1 and L2 is mediated by a unitary neural system (i.e., frontoparietal region), which is capable of recruiting surrounding cortical resources to meet the increased computational demand caused by low L2 proficiency.

Adult↗

PubMed2004

[Diagnosis and treatment of methylmalonic acidemia in 14 cases].

OBJECTIVE: Methylmalonic acidemia (MMA) is one of the most common disorders of congenital organic acid metabolism. This study aimed at exploring the clinical characteristics and treatment of the disease to help improve our understanding of it. METHODS: The clinical data of 14 patients with MMA admitted to our hospital between January 2002 and July 2003 were analyzed and the diagnoses were confirmed by gas chromatography/mass spectrometry (GC/MS). The patients consisted of 4 males and 10 females, whose age of onset ranged from birth to 9 years with 7 cases younger than 1 month (50%) and 10 cases younger than 1 year (71%). RESULTS: The main clinical manifestations were lethargy (6 cases), developmental retardation or regradation (7 cases), convulsion (6 cases), recurrent vomiting (4 cases), difficulty with feeding (4 cases), muscular dystonia (5 cases with hypotonia, 3 with hypertonia) and yellowish hair (4 cases), etc. Some cases were also presented with hair loss, hepatomegaly, ataxic or stiff gait, and motor weakness with muscular atrophy. The laboratory findings showed metabolic acidosis in 6 cases, hyperammonemia in 5 cases, ketonuria in 4 cases and remarkable elevation of urinary methylmalonic acid concentration in all cases. Some abnormalities in globus pallidus and cerebral white matter as well as diffuse cerebral atrophy were noted by the brain CT and MRI in 5 respective cases, while 4 cases did not receive neuroradiological examinations. Peripheral neuropathies were found by electromyography in 2 patients and bilateral optic nerve atrophy was detected by eyeground examination in 1 child. Three patients died before the diagnoses were made. Of the 11 survivals, 10 children have received therapy of vitamin B12 (VitB12) and supplementation of L-carnitine with restricted-protein diet. The follow-up for a period ranging from 3 months to 1.5 year (mean 8.5 months) of 7 cases with medical therapy showed a favorable outcome without any symptoms in 1 case and apparent improvement in 4 cases (the diffuse cerebral atrophy in MRI completely recovered in one case), however, 2 patients died from severe metabolic acidosis. CONCLUSIONS: The main clinical features of MMA include lethargy, developmental retardation or regradation, convulsion, recurrent vomiting, difficulty with feeding, muscular dystonia, yellowish hair, metabolic acidosis, hyperammonemia and ketonuria, etc. Urine organic acids analysis with GC/MS is critical to the early diagnosis of MMA. Early diagnosis and appropriate long-term treatment are essential to improve the prognosis of the disease.

Acidosis↗

PubMed2003

Relations between brain network activation and analgesic effect induced by low vs. high frequency electrical acupoint stimulation in different subjects: a functional magnetic resonance imaging study.

Two- or 100-Hz electrical acupoint stimulation (EAS) can induce analgesia via distinct central mechanisms. It has long been known that the extent of EAS analgesia showed tremendous difference among subjects. Functional MRI (fMRI) studies were performed to allocate the possible mechanisms underlying the frequency specificity as well as individual variability of EAS analgesia. In either frequencies, the averaged fMRI activation levels of bilateral secondary somatosensory area and insula, contralateral anterior cingulate cortex and thalamus were positively correlated with the EAS-induced analgesic effect across the subjects. In 2-Hz EAS group, positive correlations were observed in contralateral primary motor area, supplementary motor area, and ipsilateral superior temporal gyrus, while negative correlations were found in bilateral hippocampus. In 100-Hz EAS group, positive correlations were observed in contralateral inferior parietal lobule, ipsilateral anterior cingulate cortex, nucleus accumbens, and pons, while negative correlation was detected in contralateral amygdala. These results suggest that functional activities of certain brain areas might be correlated with the effect of EAS-induced analgesia, in a frequency-dependent dynamic. EAS-induced analgesia with low and high frequencies seems to be mediated by different, though overlapped, brain networks. The differential activations/de-activations in brain networks across subjects may provide a neurobiological explanation for the mechanisms of the induction and the individual variability of analgesic effect induced by EAS, or that of manual acupuncture as well.

Acupuncture Analgesia↗

PubMed2003

Modulation of cold pain in human brain by electric acupoint stimulation: evidence from fMRI.

The purpose of this study is to investigate the modulation of pain responses in the human brain by electric acupoint stimulation (EAS). Eight healthy subjects were enrolled; each received real or mock EAS treatment in separate sessions. Cool (18 degrees C) and cold (2 degrees C) stimuli were delivered, during which functional magnetic resonance imaging scans were performed, before and after treatment. Real EAS specifically increased the pain-specific activation in bilateral secondary somatosensory area, medial prefrontal cortex, and Brodmann area (BA) 32, while it decreased the activation in contralateral primary somatosensory area, BA7, and BA24. We suggest that EAS may induce an analgesic effect via modulation of both the sensory and the emotional aspect of pain processing.

Adult↗

PubMed2003

Distinct brain regions associated with syllable and phoneme.

The syllable and the phoneme are two important units in the phonological structure of speech sounds. In the brain mapping literature, it remains unsolved as to whether there are separate brain regions mediating the processing of syllables and phonemes. Using functional magnetic resonance imaging (fMRI), we investigated the neural substrate of these phonological units with Chinese subjects. Results revealed that the left middle frontal cortex contributes to syllabic processing, whereas the left inferior prefrontal gyri contributes to phonemic processing. This pattern of findings offers compelling evidence for distinct cortical areas relevant to the representation of syllables and phonemes.

Adult↗

PubMed2003

Neural basis of the non-attentional processing of briefly presented words.

The neural basis of the automatic activation of words was investigated in an fMRI study. In the study, words were presented briefly (51 or 151 msec) followed by a mask. To prevent attentional processing, subjects attended to the masks and not the words, and were required to make perceptual judgment about the masks. We found that a distributed neural network (including the frontal, temporal, occipital, parietal lobes, and the cerebellum) was activated during non-attentional processing of words in both exposure durations. A significant main effect of presentation duration was found in bilateral cerebellum and the right fusiform gyrus, suggesting their role in the later (151 msec) processing of words. In addition, a significant interaction between presentation duration and word frequency was obtained. When the presentation duration was 151 msec, no significant difference in activation was found between high- and low-frequency words. Alternatively, when the presentation duration was 51 msec, high-frequency words evoked significantly greater activation in bilateral fusiform gyri, cerebellum, right inferior parietal lobe, medial frontal gyrus (BA 45/46/9), and the right temporal-occipital junction (BA 21/37). These results suggest that these regions are sensitive to word frequency, and are related to both the attentional and non-attentional access of lexical representations.

Adolescent↗

PubMed2003

The neural substrate of analogical reasoning: an fMRI study.

This study investigated the anatomical substrate of analogical reasoning using functional magnetic resonance imaging. In the study, subjects performed a verbal analogy task (e.g., soldier is to army as drummer is to band) and, to control for activation caused by purely semantic access, a semantic judgment task. Significant activation differences between the verbal analogy and the semantic judgment task were found bilaterally in the prefrontal cortex (right BA 11/BA 47 and left BA45), the fusiform gyrus, and the basal ganglia; left lateralized in the postero-superior temporal gyrus (BA 22) and the (para) hippocampal region; and right lateralized in the anterior cingulate. The role of these areas in analogical reasoning is discussed.

Adult↗

PubMed2002

[Effects of wild-type p53 gene on the chemotherapy sensitivity of ovarian cancer SKOV-3 cells to cisplatin].

OBJECTIVE: To assess the effect of wild-type p53 gene on the chemotherapy sensitivity of ovarian cancer SKOV-3 cells to cisplatin. METHODS: Recombinant eukaryotic expression vector pcDNA3 containing full-length human wild-type p53 cDNA was introduced by lipofectamine-mediated gene transfection into SKOV-3 cultured cells which were acted on by cisplatin of different concentrations. The chemotherapy sensitivity of tumor cells with different-status p53 was observed. RESULTS: The inhibitive rate of formation of clones after p53 cDNA transfection was 56.4% compared with the untransfected one. The formation of clones decreased by 76.2% and 84.1% respectively after being acted on by 0.5 ug/ml cisplatin for 24 hours and 48 hours respectively. The formation of clones decreased by 89.5% and 93.7% respectively after being acted on by 1 ug/ml cisplatin for 24 hours and 48 hours respectively. After the introduction of p53 cDNA, the S phase and the ratio of G(2)/M phase of tumor cells decreased, and the ratio of G(1)/G(0) phase increased. The introduction of p53 gene into cells led to cell cycle arrest in G(1) phase. CONCLUSION: The exogenous introduction of wild-type p53 cDNA into ovarian cancer SKOV-3 cells increased the chemotherapy sensitivity to cisplatin.

Antineoplastic Agents↗