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Biomedical subjects

X Sun

Publications and source records attributed to X Sun.

At least 505 records · Page 28Linked to original sources
PubMed1994

[Clinical significance of intraoperative frozen biopsy of cervical lymph node for laryngeal cancer].

The results of intraoperative and postoperative pathologic examination in 102 cases of laryngeal cancer were reported. The overall consistent rate of intraoperative and postoperative biopsy was 114/116(98%). The consistent rate of positive result was 40/40(100%), while the consistent rate of negative result was 74/76(97%). The pathological and clinical results showed that the intraoperative frozen biopsy could confirm the metastasis of cervical lymph node. When frozen biopsy was positive, the neck dissection should be performed. When frozen biopsy was negative, the neck dissection should not be performed in most cases, or the functional neck dissection may be performed in some cases.

Adult↗
PubMed1994

[Cerebral blood flow and oxygen metabolism in patients with pure akinesia and progressive supranuclear palsy].

We studied cerebral blood flow and oxygen metabolism in 6 patients with pure akinesia (PA), 8 patients with progressive supranuclear palsy (PSP), 16 patients with Parkinson's disease (PD), and 10 normal control subjects using positron emission tomography (PET). Regions of interest were studied in the cerebral cortex (the frontal, temporal, parietal, and occipital lobe), thalamus, cerebellar hemispheres, cerebellar vermis, and brainstem. In patients with PA, regional cerebral blood flow (CBF) was significantly decreased in the frontal cortex, thalamus, and brainstem compared with normal control subjects. PSP patients showed significantly decreased CBF in the entire cerebral cortex, thalamus, cerebellar hemispheres, and brainstem and regional cerebral oxygen metabolic rate (CMRO2) in the frontal cortex, thalamus, and brainstem, whereas patients with PD were revealed to be normal in both CBF and CMRO2 values. In conclusion, a part of patients with PA may be in the early stage of PSP or may be atypical presentations of PSP whose symptom is only akinesia judging from the followings. 1) PET findings demonstrated a close similarity between PA and PSP; a pattern of CBF and CMRO2 decrement especially in the frontal cortex, thalamus and brainstem. 2) Patients with PA were shown to have similar pathological changes to PSP in recent studies. 3) Several authors reported that some PSP cases could show only akinesia initially, later developing dementia, supranuclear ophthalmoplegia, pseundobulbar palsy, and nuchal rigidity during their illnesses.

Aged↗
PubMed1994

[Reoperation for advanced recurrent laryngeal cancer after surgery].

Thirty-four cases of advanced recurrent laryngeal cancers after operation were treated surgically with satisfactory results. Postoperative 1-, 3- and 5-year survival rates were 63%, 40% and 40% respectively. The surgical procedures and experiences were described. We believe that surgical extirpation should be considered the best method in the management of advanced recurrent laryngeal cancer in spite of operative difficulties and dangers.

Adult↗
PubMed1993

Cerebral blood flow and oxygen metabolism in progressive dementia associated with amyotrophic lateral sclerosis.

We examined regional cerebral blood flow (rCBF) and oxygen metabolism (rCMRO2) in 4 patients with progressive dementia associated with amyotrophic lateral sclerosis (ALS), in 9 patients with classical ALS without dementia, and in 13 normal controls, using positron emission tomography with oxygen-15 gas and oxygen-15 labeled carbon dioxide. The mean rCBF and rCMRO2 in the anterior cerebral hemispheres decreased significantly in patients with progressive dementia with ALS, compared to those in controls. Patients with only ALS showed very mild reductions of rCBF and rCMRO2 which were not statistically significant. These data suggest that hypoperfusion and oxygen hypometabolism in the anterior cerebral hemispheres have an etiological relationship to deterioration of intellect in patients with progressive dementia with ALS. A significant reduction in the mean rCBF was also found in the cerebellar hemispheres in progressive dementia with ALS, while a reduction of mean rCMRO2 was not significant. Remote effects analogous to crossed cerebellar diaschisis occurring bilaterally were assumed to explain the cerebellar hypoperfusion.

Adult↗
PubMed1993

Possible role of the N-terminus of substance P in kainic acid-induced toxicity in rats.

Subcutaneously administered kainic acid (KA) in the rat results in brain damage accompanied by a behavioral response characterized by wet dog shakes (WDS), seizures and brain damage, an effect that is potentiated by opioids. Based on the potentiative effect of the N-terminus of substance P (SP) on the ability of KA to induce behavioral responses in mice, we tested the hypothesis that the N-terminus of SP also plays a role in KA-induced neurotoxicity in rats. Pretreatment i.p. with 1 or 10 nmol of SP(1-7), a major N-terminal metabolite of the undecapeptide SP, 15 min before administration of 12 mg/kg of KA potentiated the incidence of WDS. In contrast, after administration of 1 nmol of [D-Pro2, D-Phe7]SP(1-7) (D-SP(1-7)), the D-isomer of SP(1-7) and a substance P N-terminal antagonist, the intensity of KA-induced WDS was no different from those in either the KA- or saline-injected rats. However, pretreatment with D-SP(1-7) completely blocked the potentiative effect of SP(1-7) on the KA-induced WDS. While the severity of KA-induced lesions was not significantly altered by pretreatment with 1 nmol of SP(1-7), the effect of KA was not significantly different from that in control rats when administered with 1 nmol of D-SP(1-7). These results suggest a possible involvement of endogenous SP N-terminal activity in the effects following subcutaneous (s.c.) administration of KA.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

MK-801 inhibits the effects of capsaicin in the adult mouse by an action involving phencyclidine (PCP) sites not linked to NMDA activity.

Capsaicin in the adult animal causes antinociception due to the massive release of neurotransmitters, including substance P (SP), from primary afferent C-fibers. The results of the present study indicate that capsaicin-induced antinociception in the adult is sensitive to inhibition by dizocilpine (MK-801). The failure of a high dose (10 nmoles) of (+-)-3-(2-carboxypiperazin-4-yl)-propyl-1-phosphonic acid (CPP) to mimic the effect of MK-801 (1 nmole) on antinociception induced by 0.8 micrograms of capsaicin suggests that the inhibition by MK-801 is mediated by a phencyclidine (PCP) site but is not associated with NMDA activity. The inability of haloperidol (1 nmole) to affect the actions of capsaicin argues against an interaction with sigma sites. Behavioral sensitization to intrathecally administered kainic acid (KA) has been proposed to reflect similar neuronal activity to that underlying pain transmission. KA sensitization is inhibited by pretreatment with capsaicin (0.8 microgram) or SP(1-7) (10 nmoles) and the influence of MK-801, CPP and haloperidol on these inhibitory effects of capsaicin and SP(1-7) were identical to those on capsaicin-induced antinociception. These data are consistent with the hypothesis that the antinociceptive effect of capsaicin in the adult is similar to that of the N-terminus of SP, both of which involve a pathway sensitive to MK-801 but not mediated by NMDA-type activity.

Animals↗
PubMed1993

A possible glycine radical in anaerobic ribonucleotide reductase from Escherichia coli: nucleotide sequence of the cloned nrdD gene.

During anaerobic growth of Escherichia coli an oxygen-sensitive ribonucleoside-triphosphate reductase, different from the aerobic ribonucleoside diphosphate-reductase (EC 1.17.4.1), produces the deoxyribonucleoside triphosphates required for DNA replication. The gene for the anaerobic enzyme has now been cloned and was found to contain a 2136-nucleotide coding region, corresponding to 712 amino acid residues, and an Fnr binding site 228 base pairs upstream of the initiator ATG. The deduced amino acid sequence shows 72% identity to a gene of coliphage T4, sunY, hitherto of unknown function, suggesting that the virus codes for its own anaerobic reductase. The location of an organic free radical formed during activation of the bacterial anaerobic reductase is proposed to be on Gly-681, since the pentapeptide RVCGY at positions 678-682 shows a striking similarity to the C-terminal sequence. RVSGY, of pyruvate formate-lyase. During activation of the anaerobically induced pyruvate formate-lyase, the glycine residue of the pentapeptide becomes an organic radical [Wagner, A. F. V., Frey, M., Neugebauer, F. A., Schäfer, W. & Knappe, J. (1992) Proc. Natl. Acad. Sci. USA 89, 996-1000]. The gene for the anaerobic reductase is located at a position around 96 min on the E. coli genomic map.

Amino Acid Sequence↗
PubMed1993

Regulation of sigma activity by the amino-terminus of substance P in the mouse spinal cord: involvement of phencyclidine (PCP) sites not linked to N-methyl-D-aspartate (NMDA) activity.

Behavioral responses to kainic acid (KA) injected intrathecally in mice are enhanced by N-but not C-terminal fragments of substance P (SP). Repeated injections of KA result in sensitization to KA-induced activity, an effect that appears to be mediated by SP N-terminal activity and inhibited by PCP ligands. The present study was initiated to determine whether the ability of SP N-terminal fragments to enhance KA activity is also sensitive to PCP ligands. We compared the effect of a PCP ligand, dizocilpine (MK-801), to that of haloperidol, a sigma ligand and dopamine antagonist. MK-801 (1 nmol) failed to alter the enhancement of behavioral responses to KA (25 pmol) produced by SP(1-7) (22.5 pmol, 30 min). However, pretreatment with 1 nmol of either haloperidol or the N-terminal SP antagonist, [D-Pro2-D-Phe7]SP(1-7) [D-SP(1-7)], prevented potentiation of KA by SP(1-7). Like SP(1-7), 5 nmol of the sigma ligand 1,3-di(2-tolyl)guanidine (DTG) also enhanced behaviors elicited by KA, and this effect was also blocked by haloperidol or D-SP(1-7), but not spiperone (2.5 nmol), a dopamine antagonist. Together these data suggest that sigma receptors are involved in the potentiation of KA. A large dose of SP(1-7) (10 nmol) or DTG (20 nmol) did not alter the response to KA 24 hr later, yet further potentiated responses to KA 30 min after SP(1-7) (22.5 pmol) or DTG (5 nmol), suggesting sensitization to the effects of these compounds.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

MK-801 and phencyclidine act at phencyclidine sites that are not linked to N-methyl-D-aspartate activity to inhibit behavioral sensitization to kainate.

Sensitization to the behavioral effects of intrathecal kainate in mice depends on an accumulation of the N-terminus of substance P in the spinal cord and may reflect similar synaptic activity as that underlying pain transmission. The purpose of this study was to determine whether kainate sensitization, like pain, is sensitive to inhibition by phencyclidine ligands. Doses that selectively inhibit the behavioral response to a single injection of N-methyl-D-aspartate, but not kainate, were established for two non-competitive antagonists, dizocilpine (MK-801) and phencyclidine, as well as two competitive antagonists, D-amino-5-phosphonovaleric acid and (+/-)-3-(2-carboxypiperazin-4-yl)-propyl-1-phosphonic acid, of N-methyl-D-aspartate. Using these doses, we found that 1 nmol of MK-801 or 3 nmol of phencyclidine blocked sensitization to four injections of 25 pmol of kainate administered at 2 min intervals. In contrast, 1.48 nmol of D-amino-5-phosphonovaleric acid and 0.5 nmol of (+/-)-3)2-carboxypiperazin-4-yl)-propyl-1-phosphonic acid failed to alter sensitization to kainate, indicating that activation of N-methyl-D-aspartate receptors is not necessary for kainate sensitization. Haloperidol (1 nmol), a sigma receptor ligand, also failed to inhibit sensitization to kainate, suggesting that the actions of MK-801 and phencyclidine were not produced by a non-selective effect at sigma sites. Together, these data suggest that MK-801 and phencyclidine inhibit behavioral sensitization to kainate via phencyclidine receptors that are not linked to the N-methyl-D-aspartate receptor complex.(ABSTRACT TRUNCATED AT 250 WORDS)

2-Amino-5-phosphonovalerate↗
PubMed1993

Doppler flowmeter-assessed circadian rhythms in neonatal cardiac function, family history, and intrauterine growth retardation.

This study examines the circadian variation of aortic blood flow velocity, acceleration, and distance of stroke, assessed every 4 hours for 24 hours by Doppler ultrasound in 88 human newborns. Groups 1 and 2 involve neonates with a negative family history of high blood pressure or myocardial infarction monitored during the first day or between the second and tenth days postpartum, respectively; groups 3 to 6 are 2- to 10-day-old babies with a positive family history of high blood pressure (group 3) or of myocardial infarction (group 4) or with a negative family history and intrauterine growth retardation (group 5) or born prematurely (group 6). Cosinor analyses demonstrate a circadian rhythm for all variables in groups 2 and 5 (p < 0.001), with overall high values occurring around 17:40. In group 2, a circadian rhythm remains demonstrable in boys and girls considered separately, and mostly so in arbitrary subgroups of different sizes, with only slight differences in rhythm parameters among them. These results show that, with relatively small samples, reproducible circadian rhythms of cardiac function can be detected shortly after birth in neonates with a negative family history of high blood pressure or myocardial infarction.

Analysis of Variance↗
PubMed1993

Physiologic variables and fluid resuscitation in the postoperative intensive care unit patient.

OBJECTIVE: To examine how critical surgical illness and its management alter some of the biochemical, physiologic, and hematologic parameters commonly used to monitor postoperative, critically ill patients. DESIGN: Prospective survey of 150 patients over 3 months. SETTING: University hospital surgical intensive care unit. PATIENTS: A total of 150 consecutive adult patients admitted to the surgery-anesthesiology intensive care unit. MATERIALS AND METHODS: The effects of surgery on serum albumin and total protein concentrations, and lymphocyte counts were investigated. This investigation was done by comparing the values before surgery with those values after surgery and by also comparing what happened after different types of surgery. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: After surgery, decreases in serum albumin concentrations were significantly related to the estimated blood loss and acute gain in body weight from intravenous fluid resuscitation. The decreases in serum albumin and total protein concentrations were greater after elective abdominal surgery than after elective thoracic surgery. Total lymphocyte counts were significantly (< 1000 cells/mm3) reduced only in patients undergoing abdominal surgery. CONCLUSIONS: Serum albumin and total protein concentrations and total lymphocyte counts were significantly reduced by surgical injury, with significantly greater decreases seen after abdominal than thoracic surgery. These decreases were caused, in large part, by the volume of intravenous fluid used in resuscitation and blood loss. The changes in these variables are thus dependent on the type of surgical stress and the perioperative fluid therapy.

Abdomen↗
PubMed1993

Glasgow Coma Scale score in the evaluation of outcome in the intensive care unit: findings from the Acute Physiology and Chronic Health Evaluation III study.

OBJECTIVE: To investigate the ability of the Glasgow Coma Scale score to predict hospital mortality rate for adult medical-surgical intensive care unit (ICU) patients without trauma. DESIGN: A prospective cohort analysis of adult medical-surgical patients from a nationally representative sample of 40 U.S. hospitals. PATIENTS: 15,973 consecutive, nontraumatic ICU admissions and a comparison group of 687 head trauma admissions. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Patients' gender, age, treatment location before ICU admission, comorbidities, admission diagnosis, daily physiologic measurements, Glasgow Coma Scale score, Acute Physiology and Chronic Health Evaluation (APACHE III) score, subsequent hospital mortality rate, and unit-specific sedation practices were noted. Hospital mortality rates were stratified by the first ICU day Glasgow Coma Scale score for all admissions. The relationship between the Glasgow Coma Scale score and outcome for two high mortality medical diagnoses (post-cardiac arrest and sepsis) were also examined and compared to the relationship found in patients with head trauma. The Glasgow Coma Scale score on ICU admission had a highly significant (r2 = .922, p < .0001) but nonlinear relationship with subsequent outcome in ICU patients without trauma. Discrimination of patients into high- or low-risk prognostic groups was good, but discrimination in the intermediate levels (Glasgow Coma Scale score of 7 to 11) was reduced. This relationship varied within the operative and nonoperative groups, and also within different disease categories, various age groups, and certain ranges of the Glasgow Coma Scale score. A reduced initial Glasgow Coma Scale score associated with sepsis was a combination of factors associated with a higher mortality rate than that found in patients with head trauma. The proportion of patients who could not be assigned a Glasgow Coma Scale score because of sedation/paralysis varied widely across ICUs. The overall predictive capability of the APACHE III Prognostic Scoring System was improved by incorporating the Glasgow Coma Scale score. CONCLUSIONS: We demonstrated the prognostic importance of admission levels of consciousness as measured by the Glasgow Coma Scale score on ICU and hospital mortality rates. We concluded that the Glasgow Coma Scale score may be used to stratify and predict mortality risk in general intensive care patients, but lack of sensitivity in the intermediate range of Glasgow Coma Scale Score should be noted. Ideally, the Glasgow Coma Scale score should also be applied in the context of other physiologic information and the patient's specific diagnosis. Variation in the use of sedatives in different ICUs means that imputing or substituting a value other than normal for an unobtainable Glasgow Coma Scale score may introduce a substantial treatment bias into subsequent outcome predictions.

Coma↗
PubMed1993

Cardiovascular effects of alpha-trinositol in spontaneously hypertensive and normotensive Wistar-Kyoto rats.

OBJECTIVE: To investigate the cardiovascular effect of alpha-trinositol (D-myo-inositol-1,2,6-trisphosphate; PP56) in spontaneously hypertensive rats (SHR) and in normotensive Wistar-Kyoto (WKY) rats. alpha-Trinositol, a representative of a new group of pharmacological agents, is an inositol phosphate which seems to bind to a single population of binding sites, inhibiting, for example, agonist-induced vasoconstriction. In particular, alpha-trinositol seems to inhibit agonist-induced (e.g. neuropeptide Y-induced) elevations in intracellular Ca2+ levels in vascular smooth muscle cells. METHODS: alpha-Trinositol was administered as a bolus injection (2-40 mg/kg body weight), followed by a continuous infusion (20-400 mg/kg body weight per h) for 40 min in freely moving SHR and WKY rats. RESULTS: Acute intravenous bolus administration of alpha-trinositol reduced systolic and diastolic blood pressure, as well as heart rate, in a dose-dependent manner in SHR and WKY rats. After completion of the 40-min infusion the reduction in blood pressure was more pronounced in the SHR than in the WKY control rats. Heart rate did not change in the SHR, whereas it was significantly increased at the highest dosage (400 mg/kg) in the WKY rats. At this dosage, three out of eight SHR died from cardiac arrhythmias after completing the infusion. The lowest dose of alpha-trinositol administered (2 mg/kg bolus followed by 20 mg/kg per h infusion over 40 min) significantly inhibited the increase in mean arterial pressure induced by neuropeptide Y (2 micrograms/kg per min for 10 min) by approximately 30% in both the SHR and WKY rats. Furthermore, alpha-trinositol treatment completely inhibited the potentiation induced by neuropeptide Y (0.1 micrograms/min for 30 min) of the blood pressure responses to intravenous bolus injections of noradrenaline (20 ng), tyramine (40 micrograms) or angiotensin II (10 ng). CONCLUSIONS: Our results demonstrate that alpha-trinositol antagonizes the direct postsynaptic pressor response to exogenous neuropeptide Y, as well as the potentiating effects of neuropeptide Y on other vasoconstrictors in SHR and WKY rats. However, in the SHR alpha-trinositol lowered basal blood pressure only in the dose range which was non-specific for neuropeptide Y inhibition. Thus, the present study indicates that neuropeptide Y is involved only slightly in the maintenance of high blood pressure in SHR.

Animals↗
PubMed1993

Isolation of a cDNA encoding the largest subunit of TFIIA reveals functions important for activated transcription.

Transcription factor IIA has been shown to interact with the TATA-binding protein and to act early during preinitiation complex formation. The human factor is composed of three subunits (alpha, beta, gamma). A human cDNA clone encoding the largest subunit of TFIIA (alpha) was isolated. The recombinant alpha polypeptide, together with the beta and gamma subunits, was capable of reconstituting TFIIA activity. Studies using antibodies raised against recombinant alpha polypeptide demonstrate that TFIIA can be an integral component of the preinitiation complex. We demonstrate that TFIIA not only interacts with TBP but also can associate with the TFIID complex. Functional assays establish that TFIIA has no apparent role in basal transcription but plays an important role in activation of transcription. Interestingly, amino acid sequence analyses of the beta-subunit demonstrate these residues to be entirely contained within the carboxyl terminus of the cDNA clone encoding the alpha-subunit.

Amino Acid Sequence↗