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S D Lee

Publications and source records attributed to S D Lee.

At least 37 records · Page 2Linked to original sources

Role of nitric oxide in thermoregulation and hypoxic ventilatory response in obese Zucker rats.

To examine the role of nitric oxide (NO) on thermoregulation and control of breathing in obesity, awake obese and age-matched lean Zucker (Z) rats underwent a sustained hypoxic challenge. Body temperature (Tb), oxygen consumption (V O(2)) and ventilation (V E) were measured during room air and during 30-min of hypoxia (10% O(2)) after intraperitoneal administration of either 100 mg/kg of N(G)-nitro-L-arginine methyl ester (L-NAME), a nonspecific NOS inhibitor, 25 mg/kg of 7-nitroindazole (7-NI), a selective neuronal NOS inhibitor, or equal volume of vehicle (dimethyl sulfoxide: DMSO) as control. Tb in obese rats during room air was significantly lower than that of lean rats. Hypoxia induced a more pronounced drop in Tb and V O(2) in lean rats than in obese rats. Tb in lean Z rats dropped significantly by approximately 0.2 degrees C after L-NAME and, more markedly, by approximately 1.1 degrees C after 7-NI compared with control during room air, whereas Tb in obese Z rats was unaffected. L-NAME and 7-NI attenuated hypoxia-induced hypothermia or hypometabolism in lean rats, but not in obese rats. Lean rats exhibited an abrupt increase in V E in response to hypoxia followed by a gradual decline in V E. In contrast, obese rats displayed an initial increase in V E that plateaued during sustained hypoxia. Both L-NAME and 7-NI induced marked decreases in V E during room air and hypoxia compared with control lean rats, whereas V E was virtually unaffected by either agent in obese rats. The present results suggest that the blunted thermoregulatory and ventilatory responses to hypoxia in obese Z rats may be attributed to reduced activity of NOS in the central nervous system.

Animals↗

Bilateral sudden deafness as a prodrome of anterior inferior cerebellar artery infarction.

BACKGROUND: Acute ischemic stroke in the distribution of the anterior inferior cerebellar artery is known to be associated with hearing loss, facial weakness, ataxia, nystagmus, and hypalgesia. There have been few reports on bilateral deafness and vertebrobasilar occlusive disease. Furthermore, previous reports have not emphasized the inner ear as a localization of bilateral deafness. OBJECTIVE: To describe the presentation of acute ischemic stroke in the distribution of the anterior inferior cerebellar artery as sudden bilateral hearing loss with minimal associated signs. DESIGN AND SETTING: Case report and tertiary care hospital. PATIENT: A 66-year-old man with diabetes mellitus developed sudden bilateral deafness, unilateral tinnitus, and vertigo 7 days before the onset of dysarthria, facial weakness, and ataxia. T2-weighted magnetic resonance imaging scans showed hyperintensities in the right lateral pons and right middle cerebral peduncle and a possible abnormality of the left middle cerebellar peduncle. A magnetic resonance angiogram showed moderately severe stenosis of the distal vertebral artery and middle third of the basilar artery. The patient's right limb coordination and gait improved steadily over several weeks, but there was no improvement in hearing in his right ear. CONCLUSIONS: The relatively isolated onset of deafness as well as the severity and persistence of the hearing loss led us to conclude that the hearing loss in this case was likely due to prominent hypoperfusion of the internal auditory artery, with labyrinthine infarction as the earliest event. Vertebrobasilar occlusive disease should be considered in the differential diagnosis of sudden bilateral deafness.

Aged↗

Comparison of the response to the prone position between pulmonary and extrapulmonary acute respiratory distress syndrome.

OBJECTIVES: To determine whether the response to the prone position differs between acute respiratory distress syndrome (ARDS) resulting from a pulmonary cause (ARDSp) and that from an extrapulmonary cause (ARD-Sexp). DESIGN AND SETTING: Prospective observational study in a medical ICU of a university-affiliated hospital. SUBJECTS: A consecutive series of 31 patients with ARDSp and 16 with ARDSexp within 3 days of onset of ARDS. INTERVENTION: Prone position for at least 2 h. MEASUREMENTS AND RESULTS: In ARDSp, compared with the supine position (121 +/- 49 mmHg), PaO2/FIO2 was not increased after 0.5 h but was increased after 2 h in the prone position (158 +/- 60 mmHg). In ARDSexp, compared with the supine position (106 +/- 53 mmHg), PaO2/FIO2 was increased after 0.5 h (155 +/- 91 mmHg), but was not further changed after 2 h. Marked oxygenation response (increase in PaO2/FIO2 > 40% from baseline) after 0.5 h was 23% in ARDSp and 63% in ARDSexp, and that after 2 h was 29% and 63%, respectively. Static respiratory compliance decreased in the prone position in ARDSexp (30 +/- 11 ml/cmH2O at baseline, 27 +/- 11 after 0.5 h and 25 +/- 9 after 2 h) but not in ARDSp. Consolidation score as determined on the first chest radiography taken in the prone position decreased to a greater degree in ARDSexp (-2.4 +/- 4.1) than in ARDSp (0.3 +/- 4.1). CONCLUSION: Pulmonary ARDS and extrapulmonary ARDS in their early stages respond differently to the prone position with regard to the time course of oxygenation, respiratory mechanical behaviour, and radiographic change. These findings suggest that the early pathophysiology of ARDS differs according to the type of primary insult to the lung.

Aged↗

Clinical, virological, and pathological significance of hepatic bile duct injuries in Chinese patients with chronic hepatitis C.

PURPOSE: Hepatic bile duct injuries are characteristic histological findings in patients with chronic hepatitis C virus (HCV) infection. However, the pathogenesis and clinical significance of this phenomenon remain unclear. The aims of this study were to evaluate the prevalence and clinical significance of hepatic bile duct injuries in Chinese patients with chronic hepatitis C. METHODS: One hundred and seventeen Chinese patients with chronic hepatitis C were enrolled. Clinical, biochemical, immunological (serum autoantibodies and cryoglobulinemia), histological, and virological data (serum HCV RNA titer and HCV genotype) were compared between patients with and without hepatic bile duct injuries. RESULTS: Eighty-three (71%) of the 117 patients with chronic hepatitis C had hepatic bile duct injuries. Patients with hepatic bile duct injuries had a significantly higher frequency of HCV genotype 1b; a higher mean serum globulin level; significantly higher mean scores for histological periportal necro-inflammation, portal inflammation, and fibrosis; and more severe portal lymphoid aggregation/follicles when compared with patients without hepatic bile duct injuries (P < 0.05, all). No significant differences in the presence of serum autoantibodies, cryoglobulinemia, mean serum HCV RNA titer, or response to interferon treatment were noted between the two groups. Multivariate logistic regression analysis showed that HCV genotype 1b infection, portal inflammation, and lymphoid aggregation/follicles were significant independent predictors associated with hepatic bile duct injuries. CONCLUSIONS: The presence of hepatic bile duct injuries in Chinese patients with chronic hepatitis C was significantly correlated with HCV genotype 1b infection, and the patients with these injuries had more severe portal inflammation and formation of lymphoid aggregates/follicles.

Adult↗

Portopulmonary hypertension: distinctive hemodynamic and clinical manifestations.

Portopulmonary hypertension is now recognized as one of the pulmonary complications of chronic liver disease. However, previous studies reported that the incidence ranged from 0.25% to 2%, excluding fortuitous coincidence. In this study, we aimed to determine the variant hemodynamic and clinical features of portopulmonary hypertension in an area with a high prevalence of viral cirrhosis. After reviewing the hemodynamic data of 322 patients with portal hypertension admitted to the Taipei Veterans General Hospital between 1987 and 1999, we found 10 with portopulmonary hypertension. The overall incidence was, therefore, 3.1% in all patients with portal hypertension. Most of the patients with portopulmonary hypertension experienced exertional dyspnea. The survival times ranged from 2 to 86 months. In our series, most of the patients who died, died of complications related to cirrhosis and portal hypertension, but not of complications related to pulmonary hypertension. This study suggested that portopulmonary hypertension was not a frequent complication in cirrhotic patients and was not associated with an adverse outcome.

Adult↗

Real-time display of the stomach slow wave and its parameters in a newly designed electrogastrographic system.

We designed a new three-channel electrogastrographic (EGG) system, which was easily operated on the Windows 95 platform and could automatically provide slow wave parameters. The purpose of the present study was to test its reliability and accuracy in clinical recording. The system included a signal acquisition device assembled on a printed circuit board. Recorded myoelectrical signals were filtered, amplified, digitized, and transmitted via this device into a notebook personal computer (PC). Based on the short-term Fourier transform the software could transfer the time domain of the signal into the frequency domain. Real-time displayed slow wave parameters, including dominant frequency/power, percent of normal frequency (2-4 cpm), instability coefficient in frequency/power, and power ratio, were automatically renewed every 64s. Twenty healthy subjects (M/F, 12/8; age, 23-51 years) were enrolled to measure both fast and postprandial myoelectrical activities for each 30-min recording. Our results indicated that meal ingestion significantly increased dominant frequency (3.15+/-0.20 vs 3.23+/-0.23 cpm; P < 0.05) and power (26.1+/-3.8 vs 28.4+/-3.9 dB; P < 0.05). The power ratio of the meal effect was 2.02+/-2.07. Other parameters, including instability coefficient and percent of normal frequency, remained similar despite food ingestion. This newly designed EGG system is acceptable for clinically measuring gastric myoelectrical activity; the real-time display of many EGG parameters is an advantage with this new system.

Adult↗

Infectious causes of chronic diarrhea.

Chronic diarrhea can be seen in association with specific pathogens, usually parasites and occasionally some bacteria. This article reviews pathogens causing chronic diarrhea in immunocompetent individuals and provides a rational diagnostic approach.

Bacterial Infections↗

Retroperitoneal approach for aortic surgery: is it worth it?

BACKGROUND: Previous reports suggest that earlier hospital discharges and reduced postoperative complications occur when a retroperitoneal approach is used for aortic surgery. Other publications refute this concept. In an effort to determine the most cost efficient method for aortic surgery in our institution, while maintaining high standards of care and outcome, we compared the retroperitoneal approach to the conventional transperitoneal aortic operation. PATIENTS AND METHODS: Between December 1995 and April 1998, 120 patients underwent aortic surgery by either the transperitoneal (n=60) or retroperitoneal approach (n=60). All patients were enrolled prospectively in a vascular registry and retrospectively reviewed. Patients were randomly assigned to one of three vascular surgeons. A clinical pathway for elective aortic surgery was developed and applied to both groups. Patients were evaluated with respect to demographics, comorbidities, preoperative risk stratification, conduct of the operative procedure, length of stay, complications, cost, clinical outcomes and patient satisfaction. The indications for aortic surgery were similar in both groups - 64% for aneurysm disease and 36% for occlusive disease. Both symptomatic and asymptomatic aneurysms were included and size ranged from 4.4 to 14cm. All aortic reconstructions were done in the standard manner using knitted Dacron velour prostheses in either the aortic tube, bi-iliac or bi-femoral configuration. Statistical analysis of means and medians was accomplished using the Wilcoxin Rank-sum test and percentages were compared using Fisher's Exact test. P values less than 0.05 indicate statistical significance. RESULTS: There were no statistically significant differences in patient demographics. The incidence of atherosclerotic coronary artery disease, obstructive pulmonary disease, diabetes, hyperlipidemia, tobacco abuse, distal lower extremity occlusive disease and the results of chemical myocardial stress evaluations were similar in both groups. Comorbidities of pre-existing renal insufficiency/failure and morbid obesity were increased in the retroperitoneal group. Five patients in the retroperitoneal group represented redo aortic surgery and there were no redo procedures in the transperitoneal group. Length of operative procedures and blood replacement requirements for both groups were similar. The transperitoneal group required 2-3l more intraoperative intravenous (IV) crystalloid than the retroperitoneal group (P<0.0001). Statistically significant reductions in ICU days, postoperative ileus and total lengths of stay were observed in the retroperitoneal group (P<0.0001). This resulted in substantial reductions in hospital costs for the retroperitoneal group (P<0.01). Postoperative complications were similar for both groups except for statistically significant increases in pulmonary edema (P<0.01) and pneumonia (P<0.001) in the transperitoneal group. Cardiac arrhythmias, primarily atrial dysrhythmias, were more frequent in the transperitoneal group but this failed to reach statistical significance (P<0.16). Combined thirty day mortality was 0.9%. Time of recovery to full activity and patient satisfaction substantially favored the retroperitoneal group. CONCLUSION: Our clinical pathway and algorithm for aortic surgery was easily followed by those patients in the retroperitoneal approach group and resulted in decreases in ICU time, postoperative ileus, volume of intraoperative crystalloid and total length of stay. The patients in the transperitoneal group often failed to progress appropriately on the pathway. Reduced hospital costs associated with aortic surgery using the retroperitoneal approach has increased the profitability for this surgery in our institution by an average of $4000 per case and has increased the value (quality/cost) of this surgery to our patients and our institution.

Aged↗

Kidney transplantation in patients with chronic hepatitis B virus infection: is the prognosis worse?

The impact of hepatitis B virus (HBV) infection on the long-term outcome of kidney transplant patients is controversial. A total of 34 chronic hepatitis B surface antigen (HBsAg) carriers among 143 renal allograft recipients were identified in this study (mean follow-up period: 5.6+/-3.3 years; range: 1-13 years). During the follow-up, one HBsAg-positive recipient with preexisting cirrhosis died of liver failure, and seven (21%) others developed serious HBV-related complications (four fulminant hepatitis, two hepatocellular carcinoma, one cirrhosis), and four died. Although HBsAg-positive recipients had a higher rate of liver-related complications and deaths than HBsAg-negative recipients did, there were no significant differences in the long-term graft and patient survival between the two groups. The survival rates, liver-related complications, and deaths in HBsAg-positive allograft recipients and 28 HBsAg-positive uremic patients under dialysis were similar. In conclusion, HBV infection is not a contraindication to kidney transplantation. However, pretransplant candidates should be warned of potentially serious liver-related complications.

Adolescent↗

Impaired postprandial gastric myoelectrical activity in Chinese patients with nonulcer dyspepsia.

Using a homemade electrogastrography (EGG) system, we studied the characteristics of the myoelectrical rhythm in Chinese patients with nonulcer dyspepsia (NUD). Based on short-term Fourier transformation, recorded slow waves could be automatically analyzed to obtain the following parameters: dominant frequency/power, percent of normal frequency (2-4 cpm), power ratio, etc. EGG parameters, Helicobacter pylori status, histological examination of gastric mucosa, and dyspeptic symptoms were recorded in 27 NUD patients. Compared to 32 healthy controls, the Chinese NUD patients had abnormal postprandial EGG parameters including a lower percentage of regular 2-4 cpm slow waves (70.10 +/- 2.97% vs 79.08 +/- 2.95%, P < 0.05), a lower level of increment of dominant power (0.62, +/- 0.91 vs 3.76 +/- 0.58 dB, P < 0.05), lower power ratio (1.42 +/- 0.28 vs 2.79 +/- 0.39, P < 0.05) and a higher instability coefficient (0.36 +/- 0.03 vs 0.26 +/- 0.03, P < 0.05). However, Helicobacter pylori infection and its associated gastritis did not influence any EGG parameters in NUD patients. Six main dyspeptic symptoms and total symptom score had no correlation with any EGG parameters. In conclusion, Chinese NUD patients may have abnormal postprandial stomach myoelectrical activity, but these EGG abnormalities are not a direct result of Helicobacter pylori infection and its related gastritis and do not contribution to the dyspeptic symptoms.

Adult↗

Applied potential tomography in liquid gastric emptying measurement: design, assembling, calibration, and clinical application.

The present study aimed to validate the accuracy of a homemade applied potential tomography (APT) apparatus for liquid gastric emptying (GE). Twelve electrodes were placed in a circular array around the subjects. Ten electrodes in a rotated order recorded electrical current delivered from a driving pair of electrodes. Based on tomography, averaged signals of changed resistivity were constructed to display area changes. Six beakers were respectively placed into a saline-filled Perspex tank to measure their cross-sections. True beaker cross-sections are 2.01, 15.9, 18.8, 30.19, 38.48, and 63.61 cm2, respectively, whereas APT generated cross-sections were 7.9 +/- 2.9, 16.7 +/- 3.3, 22.4 +/- 4.9, 28 +/- 4.8, 48.7 +/- 7.6, 67 +/- 6.1 cm2, respectively (r = 0.98, P < 0.001). Twenty-four healthy males ingested 500-ml test solution to assess GE using both APT and scintigraphy. Only 20 (83.3%) subjects had a successful measurement. The APT half emptying time was 15.6 +/- 4.8 min, whereas scintigraphy was 21.9 +/- 6.3 min (r = 0.67, P < 0.01). In conclusion, our APT apparatus is a simple, noninvasive, and inexpensive way to assess liquid GE. Its clinical usefulness is confirmed using both phantom and human models.

Adult↗

Electrogastrographic characteristics in patients of stomach cancer.

Using a homemade electrogastrography (EGG) system, we studied the characteristics of myoelectrical rhythm in gastric cancer (GC) patients. Based on a short-term Fourier transform, recorded slow waves could be automatically analyzed to obtain the following parameters: dominant frequency/power, percent of normal rhythm (2.4-3.7 cpm), power ratio, etc. Fifty histologically confirmed GC patients (34 men, 16 women) were enrolled before surgical intervention to measure their fasting and postprandial EGG parameters for 30 min. The cancerous parameters of GC patients were then obtained postoperatively. In addition, 46 healthy subjects were enrolled for comparison. When compared to controls, GC patients had the following characteristics: absence of postprandial increase in dominant frequency (GC: 3.04 +/- 0.47 vs 3.07 +/- 0.44 cpm, NS; controls: 3.02 +/- 0.31 vs 3.21 +/- 0.25 cpm, P < 0.001), marked power response after meal (P < 0.05), and obvious power ratio (4.58 +/- 7.38 vs 2.27 +/- 2.05, P < 0.05). Multivariate analysis indicated that advanced GC was the factor responsible for the obvious dominant power enhancement after meal (P < 0.05). Other demographic, clinical, and cancerous factors did not influence EGG parameters. We conclude that apparent arrhythmia is not encountered in GC patients, although they mainly exhibit obvious postprandial power response. Advanced GC is likely responsible for this power enhancement on EGG recording.

Aged↗

Effects of heat pretreatment on histopathology, cytokine production, and surfactant in endotoxin-induced acute lung injury.

To determine the effect of heat stress on histopathology of acute lung injury (ALI) caused by administration of lipopolysaccharide (LPS), and to determine the roles of tumor necrosis factor (TNF)-alpha, interleukin (IL)-1beta, interferon (IFN)-gamma, IL-10 and surfactants in heat-induced tolerance to ALI, we administered either saline or LPS (3 mg/kg of body weight) intravenously to male Sprague-Dawley rats without and with heat pretreatment. Five hours after LPS or saline treatment (23 h after heat-pretreatment), samples were obtained. We found that the histopathologic features of LPS-induced ALI were attenuated by heat-pretreatment. Heat-pretreatment did not decrease the elevated plasma or BAL fluid levels of TNF-alpha, IL-1beta, and IFN-gamma by LPS. The plasma level of IL-10 in LPS-treated rats with heat-pretreatment, however, was increased compared to that of LPS-treated rats without heat-pretreatment (P = 0.001). There were no differences in the BAL fluid concentrations of light or heavy density pulmonary surfactant phospholipids depending on heat-pretreatment in LPS-treated rats. These observations suggest that IL-10 might play a role in decreasing LPS-induced acute lung injury after heat-pretreatment.

Acute Disease↗

Opioidergic modulation of ventilatory response to sustained hypoxia in obese Zucker rats.

OBJECTIVE: To determine whether altered central and/or peripheral opioidergic mechanisms contribute to the altered ventilatory response to sustained hypoxia in obese Zucker rats. RESEARCH METHODS AND PROCEDURES: Eight lean (176 +/- 8 [SEM] g) and eight obese (225 +/- 12 g) Zucker rats were studied at 6 weeks of age. Pulmonary ventilation ((E)), tidal volume (V(T)), and breathing frequency (f) at rest and in response to sustained (30 minutes) hypoxic (10% O(2)) challenges were measured on three separate occasions by the barometric method after the randomized, blinded administration of equal volumes of saline (control), naloxone methiodide (N(M); 5 mg/kg, peripheral opioid antagonist), or naloxone hydrochloride (N(HCl); 5 mg/kg, peripheral and central opioid antagonist). RESULTS: Administration of N(M) and N(HCl) in lean animals had no effect on (E) either at rest or during 30 minutes of sustained exposure to hypoxia. Similarly, N(M) failed to alter (E) in obese rats. In contrast, N(HCl) significantly (p < 0.05) increased (E) and V(T) both at rest and during 2 to 10 minutes of hypoxic exposure in obese rats. After 20 to 30 minutes of hypoxic exposure, V(T) remained elevated with N(HCl), but the earlier elevation of (E) seemed to be attenuated due to a decrease in f at 20 minutes of exposure to hypoxia. DISCUSSION: Thus, endogenous opioids modulate both resting (E) and the ventilatory response to sustained hypoxia in obese, but not in lean, Zucker rats by acting specifically on opioid receptors located within the central nervous system.

Animals↗

NMDA receptor-mediated modulation of ventilation in obese Zucker rats.

BACKGROUND: Ventilation in response to hypoxia is reduced in some obese humans and is believed to represent part of the pathogenesis of obesity hypoventilation syndrome (OHS). Ventilation in response to hypoxic exposure is closely related to the release of excitatory neurotransmitters, in particular glutamate, acting specifically on N-methyl-D-aspartate (NMDA) receptors. OBJECTIVES: The aim of the present study was to investigate whether NMDA receptor-mediated mechanisms are responsible for the altered ventilatory response to sustained hypoxia observed in obese Zucker (Z) rats. SUBJECTS: Seven lean and seven 15-week-old obese male Z rats were studied. MEASUREMENTS: Ventilation ([V](E)) at rest and during 30 min sustained hypoxic (10% O(2)) exposure was measured by the barometric method. [V](E) was assessed following the blinded-random administration of equal volumes of either saline (vehicle) or dextromethorphan (DM, 10 mg/kg), a non-competitive glutamate NMDA receptor antagonist. RESULTS: DM had no effects on resting [V(E) in both lean and obese rats during room air breathing. Lean rats treated with DM exhibited a significant (P<0.05) depression in [V](E), V(T), and V(T)/T(I) during either the early (5 min) or the late phase (30 min) of ventilatory response to sustained hypoxia. In contrast, DM administration in obese rats did not change [V(E), V(T), or V(T)/T(I) during the early phase of ventilatory response to hypoxia. During the late phase of ventilatory response to hypoxia. obese rats treated with DM exhibited a similar depression in [V](E) and V(T) as observed in lean rats, but had no significant change in V(T)/T(I) during the 30 min hypoxic exposure. CONCLUSION: Our findings indicate that altered glutamatergic mechanisms acting on NMDA receptors are partially responsible for a blunted early phase of ventilatory response to hypoxia noted in obese rats and also contribute to their reduced neural respiratory drive.

Animals↗