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Biomedical subjects

K L Wong

Publications and source records attributed to K L Wong.

At least 37 records · Page 2Linked to original sources
PubMed1997

Dyspnea resulting from phrenic nerve paralysis after interscalene brachial plexus block in an obese male--a case report.

Phrenic nerve paralysis is a common complication in interscalene brachial plexus block. This complication is often ignored by most anesthesiologists because no clinical symptoms occur in patients who have no underlying lung disease. We present a case of an obese male suffering from dyspnea due to phrenic nerve block after interscalene brachial plexus block. The decreased respiratory reserve and direct compressing effect of the abdominal organs on the diaphragm in the supine position are thought to be the risk factors in this obese patient. Also discussed are the incidence, diagnostic methods, clinical presentation and treatments of phrenic nerve paralysis during interscalene brachial plexus block.

Adult↗
PubMed1996

Effect of celiac ganglionectomy on tachykinin innervation, receptor distribution and intestinal responses in the rat.

Substance P (SP) is an important neurotransmitter in the control of intestinal motility and is found in both the enteric and sympathetic nervous systems. This study examined the effect of celiac ganglionectomy on (1) mechanical properties of the circular muscles of the duodenum, ileum and proximal colon, (2) circular muscle responses to SP and neurokinin A. (3) distribution of substance P-like immunoreactive nerves, and (4) the distribution of neurokinin 1 and neurokinin 2 receptors. Celiac ganglionectomy resulted in an effective sympathectomy as evidenced by a marked decrease in norepinephrine content and tyrosine hydroxylase staining in the duodenum, ileum and proximal colon. The in vitro length/tension characteristics of the circular muscle of the duodenum, ileum and colon were unchanged after ganglionectomy. In all regions of the gut studied, substance P and neurokinin A caused dose-dependent contractions that were unaltered by celiac ganglionectomy. Immunohistochemistry revealed moderate substance P-like immunoreactive fibers in the myenteric plexus, submucosal plexus and circular muscle of the ileum, while in the colon, substance P-like immunoreactivity was intense in the myenteric plexus, and moderate in the circular muscle. In vitro autoradiography showed minimal binding of SP (NK1 receptor) or neurokinin A (NK2 receptor) in the ileum and significantly greater binding in the circular muscle layer of the colon. Celiac ganglionectomy did not affect substance P-like immunoreactivity, or NK1 or NK2 receptor binding. A greater contractile response to neurokinins was seen in the colon than in the duodenum or ileum, which paralleled the receptor density. The studies demonstrate that surgical celiac ganglionectomy, unlike chemical sympathectomy, does not affect the substance P innervation, receptor density or physiological responses of the intestine. The greater contractile response of the colon than the ileum parallels the greater receptor density rather than the peptide content as determined by immunhistochemistry.

Animals↗
PubMed1996

Evaluation of fluorinated indole derivatives for electron-capture negative ionization mass spectrometry: application to the measurement of endogenous 5-methoxyindole-3-acetic acid in rat.

A series of N-trifluoroacetyl/pentafluoropropionyl-O-trifluoroethyl/ pentafluoropropyl/heptafluorobutyl ester derivatives of 5-methoxyindole-3-acetic acid (5MIAA) were synthesized. Under electron-capture negative ionization conditions, the N-trifluoroacetyl derivatives were found to yield relatively abundant, analyte-specific M-. molecular ions and [M-HF]-., [M-HF-CF2CO]-. and [M-CF3CO]- fragment ions, while the N-pentafluoropropionyl derivatives yielded predominantly the reagent-specific pentafluoroacylium C2F5CO- ion. 5-[2H3]Methoxyindole-3-acetic acid was prepared in high yield by a new synthetic procedure and used as the internal standard in subsequent gas chromatographic/mass spectrometric analysis. Using the N-trifluoroacetyl-O-pentafluoropropyl ester derivative, femtomole to low picomole per gland/organ per g ml-1 levels of endogenous 5MIAA were identified and determined in the rat pineal gland, retina, whole brain and serum.

Animals↗
PubMed1996

The accuracy of bioimpedance cardiography in the measurement of cardiac output in comparison with thermodilution method.

BACKGROUND: Continuous noninvasive measurement of cardiac output (CO) is clinically desirable. Thoracic electrical bioimpedance (TEB) offers such a continuous noninvasive technique for the measurement of CO on a beat-by-beat basis. The purpose of this study was to compare the correlation of TEB with the thermodilution (TD) method of measuring CO during surgery. METHODS: Eighteen patients (age 39-64 yr), with coronary artery disease undergoing coronary artery bypass graft surgery were studied. Patients were excluded if severe arrhythmias or aortic insufficiency was present before operation. Simultaneous measurements of CO were performed in each patient with the use of a 7F Swan-Ganz catheter and TEB. 128 matched pair values were obtained and compared using regression analysis. Bias (mean difference between measurements) and limits of agreement with 95% confidence limits were also calculated. RESULTS: A good correlation (correlation coefficient, r = 0.86; TEB = 0.55 + 0.82TD, p < 0.001) between the two methods of measuring CO was observed, and the standard error was small (SE = 0.218). The mean difference between CO measurements (TEB-TD) was -0.66 L/min and had a 95% confidence interval of 0.12 to 0.98 L/min. The standard deviation of the difference was 0.915 L/min and the limits of agreement were from -2.49 to 1.17 L/min. There appeared to be a good agreement between TEB and TD CO measurement in this study. CONCLUSIONS: Technological advances in TEB have resulted in more accurate CO measurements. Such device offers a noninvasive alternative to the TD technique for the determination of CO, and may potentially be very useful as a powerful, noninvasive, continuous technique for monitoring cardiac function in the clinical setting.

Adult↗
PubMed1995

Sequential therapy for diffuse proliferative and membranous lupus nephritis: cyclophosphamide and prednisolone followed by azathioprine and prednisolone.

A retrospective single-center cohort study was conducted on 35 patients with diffuse proliferative (WHO type IV) and/or membranous (type V) lupus nephritis (22 with type IV, 6 with type V, and 7 with type IV plus V) who had been treated with a sequential regimen comprising prednisolone and cyclophosphamide during active disease, followed by low-dose prednisolone and azathioprine maintenance. The follow-up period was 33.2 +/- 4.5 months. At presentation, 32 (91.4%) patients were nephrotic, and an abnormal serum creatinine level was noted in 14 (48.3%) patients with type IV changes. Cyclophosphamide was given for 26.8 +/- 2.8 weeks. 33 (94.3%) patients achieved complete or partial renal remissions: 77.3 and 22.7% of the type IV patients, 16.7 and 66.6% of the type V patients, and 14.3 and 71.4% of the type IV plus V patients, respectively (p < 0.0001 for type IV versus type V and for type IV versus type IV plus V). The duration of therapy before renal remissions and normalization of C3 were attained was similar among the three groups of patients. Disease relapse occurred in 4 (18.2%) of 22 IV patients and in 1 of the 5 type V patients in remission. Mortality was not observed, and none of the patients had an increase in serum creatinine level to double the baseline value. Adverse effects related to therapy included: hair loss (42.9%), transient amenorrhea (53.6%), leukopenia (11.4%), febrile episodes (14.3%), and herpes zoster(28.6%). We conclude that sequential use of prednisolone and cyclophosphamide followed by low-dose prednisolone and azathioprine can achieve favorable therapeutic results in the majority of patients with diffuse proliferative and/or membranous lupus nephritis, without excessive toxicities.

Adult↗
PubMed1994

Extracellular matrix components secreted by microvascular endothelial cells stimulate preadipocyte differentiation in vitro.

Paracrine interaction between preadipocytes and microvascular endothelial cells may play a role in the regulation of adipose tissue growth. We report here a study of the effect of extracellular matrix factors secreted by microvascular endothelial cells, derived from adipose tissue, on preadipocyte differentiation in primary culture. Extracellular matrix components (EC) were prepared by differential centrifugation of medium conditioned by microvascular endothelial cells (CM). Preadipocyte differentiation was assessed by enumerating cells containing Oil-Red-O-stainable neutral lipids and by assaying cellular triacylglycerol (TG) content and glycerol-3-phosphate dehydrogenase (GPDH) specific activity. Both supernatant (containing soluble components) and pelleted (containing large complexes of EC) fractions of CM stimulated preadipocyte differentiation. When the supernatant fraction was used, the proportion of cells containing visible lipid droplets was 29% +/- 3% of total preadipocytes in the presence of extracellular complexes, as compared with 6% +/- 1% under control conditions. This differentiation induction was associated with fourfold increases in TG content and GPDH specific activity. Neither the supernatant nor the pelleted fraction of EC affected the maximal differentiation induced by hormonal stimulation in serum-supplemented or serum-free media. The major EC, fibronectin, laminin, and collagen IV, had no effect on differentiation when added individually to culture medium. Collection of CM under hyperglycemic (18 mmol/L glucose) compared with control (6 mmol/L glucose) conditions reduced the stimulatory effect of extracellular complexes by twofold, suggesting decreased or altered production by endothelial cells. The present findings demonstrate that microvascular endothelial cells release EC that promote preadipocyte differentiation.(ABSTRACT TRUNCATED AT 250 WORDS)

Adipocytes↗
PubMed1994

[Surgical patients' attitude towards anesthesia].

There are few studies assessing the degree of understanding of anesthesia among surgical patients in Taiwan. So we designed a questionnaire to explore patients' attitude toward anesthesia. 505 patients scheduled for routine surgery were included in this study. We found there were great differences between the patients in their attitude toward and understanding of anesthesia. It is clear that we must give much more attention to communicating clearly with our patients in this regard. Further detailed studies may be useful in revealing particular area of misunderstanding.

Adolescent↗
PubMed1993

Amitriptyline inhibits neurite outgrowth in chick cerebral neurons: a possible mechanism.

Previous studies showed that amitriptyline (AMI), a tricyclic antidepressant, inhibited neurite outgrowth from chick embryonic cerebral explants and inhibited adenylyl cyclase activity in cerebral membrane preparations. In the present study, we have investigated the possibility that AMI may have additional effects on cellular metabolism and signal transduction that underlie AMI-mediated inhibition of neurite outgrowth. In vitro, AMI inhibited phospholipase C in a dose- and GTP-dependent manner in membranes from 8-day-old chick forebrain. Brain homogenates from 8-day-old chick embryos, treated in vivo for 6 days with AMI (20 micrograms/g/day), showed significant reductions in (1) phosphorylation of two polypeptides (49 and 105 kD), and (2) levels of three polypeptides (43, 53, and 92 kD). Western blots showed that the 43- and 53-kD polypeptides corresponded to actin and tubulin, respectively. Diolein and dilinolein, potent activators of protein kinase C, stimulated neurite outgrowth and reversed the inhibitory effects of AMI. Sphingosine, a protein kinase C inhibitor, significantly inhibited neurite outgrowth and eliminated the stimulatory effects of diolein and dilinolein on neurite outgrowth. These data suggest that AMI-mediated inhibition of neurite outgrowth involves multiple effects on cellular metabolism and signal transduction. A hypothesis consistent with our data is that AMI interferes in some manner with the action of G proteins in the signal transduction cascade.

Adenylyl Cyclases↗
PubMed1993

B-cell and T-regulatory cell dysfunction in six Chinese children with hypogammaglobulinaemia.

We report six Chinese boys with hypogammaglobulinaemia. All but one had very low or undetectable circulating B-lymphocytes, two had reversed CD4/CD8 ratios (in one of whom this latter became normal), one had reduced lymphocyte proliferative responses to concanavalin A and pokeweed mitogen and three had deficient responses to OKT3. Generation of antibody-secreting cells in response to pokeweed mitogen was markedly defective in all patients. Co-cultures of purified lymphocyte subsets from the patients with those of normal donors revealed that in addition to B-cell deficiency seen in all patients, two had T-helper cell deficiency and two had T-suppressor cell hyperactivity. One of the latter patients was treated with cimetidine in an attempt to ablate histamine type 2 receptor-bearing suppressor cells: the absolute number of such cells was temporarily reduced but there was no concurrent correction of the functional hyperactivity. These studies point to the variable nature of T-regulatory cell deficiencies in hypogammaglobulinaemia.

Adolescent↗
PubMed1993

Disseminated skeletal tuberculosis with skull involvement.

We report a patient with widespread osteolytic lesions, including extensive involvement of the skull, due to Mycobacterium tuberculosis. Response to treatment with antituberculosis drugs was slow with appearance of new lesions while on therapy despite a sensitive organism. Excision of diseased skull bone was eventually done, after which no new lesions appeared in the ensuing 14 months.

Adolescent↗
PubMed1993

Resolution of membranoproliferative glomerulonephritis complicating angiofollicular lymph node hyperplasia (Castleman's disease).

A novel renal complication was reported in a patient with angiofollicular lymph node hyperplasia (Castleman's Disease), who developed acute renal failure due to membranoproliferative glomerulonephritis. Renal biopsy showed marked mesangial hyperplasia, basement membrane thickening with subendothelial electron-dense deposits, interstitial plasma cell infiltration, and glomerular deposition of IgM and complement components. A resolution of systemic manifestations and an improvement in renal function followed prednisolone and azathioprine therapy. Disease relapse, with increasing proteinuria and the development of factor 8 inhibitor, occurred 3 months later. Sustained remission was achieved with prednisolone and cyclophosphamide therapy, which were given for 42 and 12 months, respectively. Renal biopsy during remission showed significant resolution of the mesangial hyperplasia and disappearance of interstitial plasmacytic infiltration as well as subendothelial electron-dense deposits.

Adult↗
PubMed1993

Prognostic value of an abnormal signal-averaged electrocardiogram in patients with nonischemic congestive cardiomyopathy.

BACKGROUND: An abnormal signal-averaged ECG (SAECG) has predictive value for arrhythmic events in patients with coronary artery disease. The purpose of this study was to investigate whether an abnormal SAECG could provide prognostic information in patients with nonischemic dilated cardiomyopathy. METHODS AND RESULTS: We prospectively obtained SAECGs in 114 patients with dilated nonischemic cardiomyopathy. Twelve-lead ECGs, left ventricular ejection fractions, hemodynamic measurements, and peak exercise oxygen consumption (VO2) also were measured. An SAECG was defined as abnormal by any one of the three following criteria: filtered QRS duration > 120 msec, root-mean-square voltage in the last 40 msec < 20 microV, or duration < 40 microV > 38 msec at 40 Hz. Sixty-six patients had a normal SAECG, 20 patients had an abnormal SAECG, and 28 patients had bundle branch block (BBB). Mean follow-up was 10 +/- 5 months. Age, ejection fraction, peak VO2, pulmonary capillary wedge pressure, and cardiac index were not statistically different among the three groups. Use of antiarrhythmic drugs was similar among the three groups, although patients with BBB had more implantable defibrillators (p < 0.05). The incidence of previous atrial arrhythmias was similar for the three groups. Patients with abnormal SAECG or BBB had more past episodes of sustained ventricular tachycardia and/or sudden death episodes (n = 9) than patients with normal SAECG (n = 1) (p < 0.01). Prospectively, none of the 66 patients with normal SAECG died suddenly or had sustained ventricular arrhythmias. Two deaths occurred from progressive heart failure, and three patients required urgent transplant. In the 20 patients with an abnormal SAECG, four patients had sustained ventricular tachycardia, five patients died suddenly, two patients died from progressive heart failure, and one patient required urgent transplant. In the patients with BBB, four patients had sustained ventricular tachycardia, and four patients required urgent transplant. One-year event-free survival, i.e., absence of ventricular tachycardia and/or death, was 95% in patients with normal SAECG, 88% in patients with BBB, and only 39% in patients with an abnormal SAECG (p < 0.001). Multivariate analysis demonstrated that SAECG and New York Heart Association classification were independent predictors of survival. CONCLUSIONS: Patients with an abnormal SAECG had a statistically significant increase in sustained ventricular arrhythmias and/or death than did patients with a normal SAECG or BBB. This study demonstrates that an abnormal SAECG is a marker of past and future arrhythmic events in patients with nonischemic dilated cardiomyopathy. In contrast, patients with a dilated cardiomyopathy with a normal SAECG have an excellent prognosis with adverse outcome only from progressive heart failure.

Bundle-Branch Block↗
PubMed1993

Rheumatoid nodules in the trachea.

We describe the first case of endotracheal rheumatoid nodules in a 45-year-old Chinese man with rheumatoid arthritis. He developed exacerbation of polyarthritis, new subcutaneous nodules and fibrosing alveolitis. At bronchoscopy, four whitish nodules were detected at the tracheal wall, and biopsy showed fibrinoid necrosis, palisaded inflammatory cell infiltrate and vasculitis, consistent with rheumatoid nodules. Both tracheal and subcutaneous nodules regressed with orally administered prednisone.

Arthritis, Rheumatoid↗
PubMed1993

[Nifedipine in preeclampsia for cesarean section].

The patients with preeclampsia undergoing emergent cesarean section is always a challenge to an anesthesiologist, because severe hypertensive response after laryngoscopy and tracheal intubation may result in life-threatening complication such as cerebral hemorrhage. Most of these patients receive magnesium sulfate for the prevention of convulsion. An ideal anti-hypertensive drug for preeclampsia should be effective, limited fall in blood pressure, rapid onset, maintaining uteroplacental blood flow, and less maternal and fetal side effects. We studied the efficacy of 10 mg sublingual nifedipine in attenuating the pressor response to intubation. We were also concerned about whether this calcium antagonist may inhibit uterine contraction and increase intra and postpartum hemorrhage when it is used with magnesium sulfate and general anesthesia. There were thirty-three patients in our study (16 in nifedipine group and 17 in control group). This study revealed that nifedipine attenuate the hypertensive response effectively. Uterine contraction response to oxytocic drugs was quite well in both groups. There was no significant difference in blood loss between nifedipine and control group. And no severe maternal and fetal adverse effect.

Adult↗
PubMed1993

[Anesthetic management of intraoperatively diagnosed pheochromocytoma--a case report].

Pheochromocytoma is a catecholamine secreting tumor originating from the adrenal medulla (up to 90%), or from the chromaffin tissue along the paravertebral sympathetic chain. The hallmark of pheochromocytoma is paroxysmal hypertension associated with diaphoresis, headache, tremulousness, and palpitations. The triad of diaphoresis, tachycardia, and headache in hypertensive patients is highly suggestive of pheochromocytoma. Other symptoms like flushing, nausea, vomiting, personality changes, and visual disturbances may however cast doubt on the diagnosis of pheochromocytoma. Death resulting from pheochromocytoma is usually due to congestive heart failure, myocardial infarction, or intracerebral hemorrhage. Although less than 0.1 percent of patients with hypertension have a pheochromocytoma, nearly 50 percent of the mortality with unsuspected pheochromocytoma occurred during anesthesia and surgery or parturition. Patients of unsuspected pheochromocytoma have higher risk for surgery, because some mandatory pre-op medical treatments might have been ignored. It is also a challenge to anesthesiologists to handle unsuspected hypertensive crisis during anesthesia and surgery. We presented such a case of unexpected Pheochromocytoma which was mis-diagnosed by the surgeon and was treated as an ordinary adrenal gland tumor and was scheduled for surgical operation. When the patient was undergoing excision of the tumor, manipulations of the tumor initiated an tremendous elevation of the blood pressure. Upon reviewing her history of normotension with visual disturbance, nausea and restlessness, she was immediate treated as with a pheochromocytoma. Appropriate managements were applied to control her abnormally high fluctuating blood pressure with success and with no complications or adverse effect.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenal Gland Neoplasms↗
PubMed1992

Pattern of SLE in Hong Kong Chinese: a cohort study.

One hundred and fifty six Chinese patients with Systemic Lupus Erythematosus (SLE) were studied prospectively over 50 months. The patients in the retrospective group (Group I) were diagnosed before and in the prospective group (Group II), at the time of entry into the study. The overall female to male ratio was 25:1 with mean age at onset (+/- SD) of 26 +/- 9.9 years. Neurological manifestation as the presenting feature was rare (3%), and none of the untreated patients presented with infection. Anti-nuclear antibody (ANA) was positive in 94% and anti double stranded-DNA antibody (anti DNA) 65%. New manifestations developed in 34 patients (26%) and 218 episodes of relapses occurred in 100 patients with a rate of 0.042 relapse per patient month. Five patients died during the study period with a 5 year survival of 97% and 10 year survival of 94% in the cohort. There was no significant difference in survival between Group I and Group II patients at 50 months (p = 0.72).

Adolescent↗