Biomedical subjects

G J Tang

Publications and source records attributed to G J Tang.

31 records · Page 2Linked to original sources

PubMed1995

Animal experimental myelography in the pig. A comparison between iohexol and iotrolan.

RATIONALE AND OBJECTIVES: The authors compared the effects of a nonionic monomeric, iohexol (Omnipaque, 300 mg I/ml), and a nonionic dimeric, iotrolan (Isovist, 300 mg I/ml), contrast medium in the spinal subarachnoid space of the pig. METHODS: Lumbar and lateral C1-C2 punctures were performed in 10 pigs. Ten milliliters iohexol or iotrolan were injected via the lumbar needle. Blood pressure, electrocardiogram, intravesical pressure, and cerebrospinal fluid pressure were recorded during the injections and at intervals for 4 to 5 hours after the injections. Blood samples were taken at 30, 60, 120, 180, 240, and 300 minutes after the injections and analyzed for iodine concentration. RESULTS: No changes were seen during the injections, and there were no differences in the blood pressure, cerebrospinal fluid pressure, electrocardiographic recordings, or in the plasma iodine concentrations during the first 4 to 5 hours after the injections. Short-lasting, rhythmic bladder contractions were seen during some injections with both iohexol and iotrolan. CONCLUSION: Both iohexol and iotrolan were well tolerated, and there was no significant difference between them. and there was no significant difference between them.

Animals↗

PubMed1995

The role of flow cytometry in non-resected cervical carcinoma.

Flow cytometry (FCM) has a prognostic value for many malignant neoplasms in terms of treatment response rate and survival. However, its role in non-resected cervical carcinoma remains uncertain. We have collected 96 paraffin-embedded specimens taken from non-resected cervical cancer patients treated by radiotherapy (RT) alone between 1984 and 1986. Our data revealed that FCM has little correlation with patients' age, pathological grade and clinical stage. Ploidy pattern and clinical stage correlate significantly with complete remission (CR) rate (p = 0.001 and 0.03). Most diploid or low-stage tumours (IB to IIA) obtained CR after RT alone. The application of an intravaginal extension electron cone (IVEC) (p = 0.019) and CR status (p = 0.0001) yield significant better overall survival (OS) rates than their alternative groups. The Cox regression model has confirmed these two variables as having an independent influence on OS. We thus conclude that both ploidy pattern and S-phase fraction (SPF) predict neither pre-treatment biological behaviour of the tumours nor overall survival. However, ploidy pattern has an independent influence on CR rate.

Adult↗

PubMed1994

The role of submucosal oedema in increased peripheral airway resistance by intravenous volume loading in dogs.

Pulmonary congestion leads to an increase in airway resistance. It is still unknown whether this is due to vascular engorgement or to submucosal oedema. The present study was designed to determine the relative contribution of these two potential mechanisms. We examined the effect of intravenous volume loading on canine peripheral airway resistance (Rp). Bronchoscopes were wedged in contralateral sublobar segments and used to record Rp during rapid infusion of normal saline. Volume loading with normal saline increased pulmonary capillary wedge pressure (PCWP) and Rp. Unlike normal saline, dextran 70 did not increase Rp when infused at a rate that produced similar changes in PCWP. During infusion of normal saline, delta Rp was significantly enhanced in lung segments previously challenged with dry air when compared to contralateral control lungs, unexposed to dry air, and the use of dextran 70 significantly reduced this effect. Vasoconstriction with phenylephrine significantly decreased baseline Rp, but did not completely reverse the effect of fluid infusion. In addition, in lung segments exposed to dry air, delta Rp was significantly greater after volume loading and treatment with phenylephrine when compared to contralateral control lung. Finally, muscarinic receptor blockade was ineffective in preventing Rp from increasing during infusion of normal saline. Our results suggest that volume loading-induced increases in Rp are not caused by either vascular engorgement or the stimulation of muscarinic receptors.(ABSTRACT TRUNCATED AT 250 WORDS)

Airway Resistance↗

PubMed1994

[Protrusion of thoracic intervertebral disk: report of 11 cases].

The authors reported 11 cases of thoracic intervertebral disk protrusion examined with plane film, myelography, CT and CT-myelography in 11 cases and MR imaging in 3. All of the 11, cases were confirmed by operation. There were 13 protrusions in the 11 cases with the locations of T10-11 in 4, T11-12 in 5 cases and T12-L1 in 4. 9 protrusions fell into central type, 1 into paracentral type and 1 into lateral type. The clinical symptoms were prominent with all 11 cases, however, most primary clinical diagnoses were erroneously given as lumber intervertebral disk protrusions and even the disorders of heart, lung, alimentary tract and urinary system. It was concluded that the main causes of the misdiagnosis included: (1) not easily to think of this entity for the clinic physicians due to its low incidence, (2) the untypical clinical manifestations. The authors considered that the exam method with the highest accuracy is CT-myelography.

Adult↗

PubMed1994

Seizure after reversal of benzodiazepine treatment with flumazenil: a report of two cases.

Two patients developed seizure immediately after flumazenil administration that aimed to reverse the prolonged sedative effect of diazepam. The use of benzodiazepine for sedation in ICU may mask valuable information relevant to an ongoing pathological change. The seizure in our patients seemed most likely to result from septic encephalopathy which was unmasked by flumazenil. However, flumazenil has the potential to provoke seizure and should be used with caution.

Aged↗

PubMed1992

The autonomic nervous system modulates dry air-induced constriction in the canine lung periphery.

To determine the modulatory role of the autonomic nervous system on dry air-induced bronchoconstriction (AIB) in the canine lung periphery, we examined the effect of cholinergic, alpha- and beta-adrenergic, and total autonomic ganglionic blockade on AIB. Pretreatment with atropine significantly attenuated AIB by approximately 30%, indicating that AIB is partially mediated via a vagal reflex. Pretreatment with either phentolamine or propranolol did not affect AIB, indicating that alpha- and beta-adrenoceptors, respectively, were not activated in response to dry air challenge. In contrast, pretreatment with hexamethonium significantly potentiated AIB. In addition, exogenous vasoactive intestinal peptide (VIP), a potential neurotransmitter for the nonadrenergic-noncholinergic (NANC) inhibitory system, significantly inhibited AIB. We conclude that (1) neither alpha- or beta-adrenergic efferents are activated during dry air challenge, (2) total autonomic blockade potentiates the response to dry air, and (3) VIP attenuates AIB. Based on these observations, we speculate that NANC inhibitory activity may be stimulated during dry air challenge and antagonizes AIB.

Animals↗

PubMed1990

The hemodynamics and clinical effects of labetalol in hypotensive anesthesia.

Labetalol is a relatively new and unique hypotensive agent that has both alpha- and beta-adrenoceptor blocking properties. 12 patients in fit physical condition who underwent elective oral surgery were subject to hypotensive anesthesia with labetalol to assess the hemodynamic aspects and clinical effects of the drug. All of them had their anesthesia maintained with halothane and N2O in 50% O2 supplemented by fentanyl and vecuronium. Initiation of deliberate hypotension was made with intravenous bolus of labetalol at 0.5 mg/kg and the ideal level of mean arterial pressure at 55 +/- 5 mm Hg was maintained with adjustment of the concentration of halothane. At the termination of deliberate hypotension, the blood pressure was recuperated to the baseline level by lowering the concentration of halothane and administration of 0.5-0.6 mg intravenous atropine. Our results showed that the total dose of labetalol used was 44 +/- 13 mg and blood loss amounted to 354 +/- 136 ml. Important changes of hemodynamic parameters before and after labetalol included the fall of mean BP, HR, mean PAP, CI, LVSWI, SVRI, PVRI and O2 delivery and the increasing of O2 extraction. As to CVP, PCWP, SVI, O2 consumption and shunting the alterations were minimal. Blood gas analysis showed that, save a slight fall of pH indicating mild metabolic acidosis, the PaO2 and PaCO2 remained unchanged following the use of labetalol. Labetalol-induced hypotension could be effectively reversed by using of atropine as shown in our study and all the patients recovered uneventfully from hypotensive anesthesia. They were entirely free from any complication or sequela relevant to the deliberate hypotension after one year's follow-up.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed1989