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Biomedical subjects

W C Wu

Publications and source records attributed to W C Wu.

At least 73 records · Page 4Linked to original sources
PubMed1996

Glycine produced pressor responses when microinjected in the pressor areas of pons and medulla in cats.

In 24 cats under chloralose/urethane anesthesia changes of systemic arterial pressure (SAP) and sympathetic vertebral nerve activities (VNA) were induced by microinjection of glycine (Gly, 1.0 M, 50 nl) into the pressor areas of the rostral pons, i.e., locus coeruleus-parabrachial nucleus (LC-PBN), nucleus of gigantocellular tegmental field-lateral tegmental field (FTG-FTL), and dorsomedial (DM) and ventrolateral (VLM) medulla. The effects were compared with those induced by microinjection of sodium glutamate (Glu, 0.25 M, 50 nl) into the same sites. In about 60% of the injections Gly produced increases in SAP and VNA similar to that of Glu. The increase in SAP was greater in VLM, while the increase in VNA was more marked in DM. In the rest of microinjections Gly and Glu produced changes of SAP and VNA in different combinations. The latency of Gly-induced increases in SAP and VNA was 1 to 3 s longer than that induced by Glu. Our findings show that although Gly is classified as an inhibitory transmitter, it often produced excitation of the pressor neurons in the pons and medulla similar to that of Glu. Whether Gly acts through the same cardiovascular neurons that respond to Glu or through activation of different kinds of neurons remains to be elucidated.

Animals↗
PubMed1996

Nipple reduction with a modified circumcision technique.

Several methods of reduction of the hypertrophic nipple have been reported. All of them have some drawbacks. We propose a technique that can be easily performed and can produce excellent aesthetic as well as good functional results.

Adult↗
PubMed1996

Reversible esophageal motility disorder in a patient with sarcoidosis.

We report the case of a patient who presented with new onset of dysphagia for solids and liquids. Her condition was subsequently diagnosed as sarcoidosis on the basis of granulomatous inflammation in tissue obtained from transbronchial fine needle aspiration, noncaseating granulomas in a full-thickness lip biopsy, mild uveitis on slit lamp examination, and serum angiotensin-converting enzyme activity of 120 U/L. Esophageal manometry revealed a nonspecific esophageal motility disorder with 60% nontransmitted contractions and a lower esophageal sphincter that failed to relax with wet swallows. The patient was treated with 40 mg prednisone per day, and within 2 wk her dysphagia had markedly improved. Prednisone was continued with a slow taper, and after 1 month ber dysphagia had resolved and her esophageal manometry was normal. To our knowledge, this is the first case of sarcoidosis presenting with dysphagia and documented esophageal dysmotility in which symptoms and manometric abnormalities normalized after therapy with systemic corticosteroids.

Adult↗
PubMed1995

Complete two-handed laparoscopic appendectomy: report of 100 cases.

A complete two-handed technique for laparoscopic appendectomy is described. From April 1992 to July 1994, 100 patients with suspected acute appendicitis were selected to undergo this approach. This technique allows the surgeon to manipulate instruments with both hands for dissecting, transecting and removing the appendix. The appropriate placement of three cannulas in the lower abdominal midline makes this technique possible. Monopolar cautery is used to dissect the mesoappendix and to cauterize the appendicular vessels. Two ligatures are placed at the junction of the appendix with the cecum. The appendix is clamped at its base by ratchet forceps and is extracted along with the forceps immediately after transection. None of the patients selected for this procedure required conversion to open appendectomy. Postoperative complications occurred in four patients, two with umbilical wound infections and two with intra-abdominal abscesses; 12 patients had perforated appendicitis. The results of this study suggest that a complete two-handed laparoscopic appendectomy can be safely and successfully accomplished in patients with suspected acute appendicitis.

Acute Disease↗
PubMed1995

Carbachol, glycine and gamma aminobutyric acid also activate cardiovascular neurons of pontomedulla responsive to glutamate.

Thirty-three cats under intraperitoneal chloralose (40 mg/kg) and urethane (400 mg/kg) anesthesia were used to explore the effect of microinjections (100 nl) of carbachol (CCh, 0.5 M), a cholinergic analogue, glycine (Gly, 1 M) and gamma aminobutyric acid (GABA, 0.4 M) on the cardiovascular-reactive sites in the pontomedulla that responded to microinjection of monosodium glutamate (Glu, 0.25 M, 100 nl) resulting in changes of systemic arterial pressure (SAP). Brain sites under exploration included gigantocellular tegmental field and lateral tegmental field (FTG-FTL), the dorsomedial (DM) and ventrolateral (VLM) medulla which produced pressor responses; caudal VLM (CVLM) and paramedian reticular nucleus (PRN) which produced depressor responses. It was found that CCh produced significant fall of SAP in DM and VLM while the rise of SAP in the same site by Glu. CCh produced SAP decrease in CVLM similar to Glu. GABA significantly caused a slight to moderate increase of SAP in FTG-FTL, DM and VLM, and decrease of SAP in CVLM, all in direction similar to that of Glu. Gly produced significant and marked increase of SAP in DM and VLM similar to Glu both in magnitude and duration. Gly produced increase of SAP in CVLM but the fall of SAP by Glu. PRN was relatively non-reactive except a few microinjections of CCh which produced hypotension. In conclusion, the cardiovascular-reactive sites in the pontomedulla that respond to Glu may also react to other chemicals or neurotransmitters. It is highly possible that multiple receptors of different nature co-exist in neurons of some cardiovascular regions in the pontomedulla.

Animals↗
PubMed1994

Correlation of lower esophageal mucosal ring and lower esophageal sphincter pressure.

We assessed the relationship of lower esophageal sphincter pressure (LESP) to presence and absence of lower esophageal mucosal ring (LEMR) in 66 patients to determine if the LEMR was more likely related to prolonged sphincter hypotension. This potential relationship is of interest because LEMR may be due to reflux esophagitis. Each patient had radiographic and manometric studies, and both examinations were done within one week of each other. The mean LESP in patients with LEMR was 23.8 mm Hg (range 4.2-64 mm Hg) compared to 28.7 mm Hg (range 8-59 mm Hg) in patients without LEMR; the difference was not statistically significant. Patients with LEMR were also divided into three subgroups according to the diameter of the rings (< or = 13 mm, 14-19 mm, > or = 20 mm). There was no significant relationship between the caliber of LEMR and LESP (P > 0.05). Presence of LEMR did not affect the amplitude or duration of primary esophageal peristalsis. These results do not support a relationship between LEMR and prolonged LESP hypotension or abnormal esophageal motility. However, other pathogenetic mechanisms involved in producing reflux esophagitis not related to prolonged sphincter hypotension were not studied.

Esophageal Motility Disorders↗
PubMed1994

Activation of neurons in cardiovascular areas of cat brain stem affects spinal reflexes.

In 65 cats anesthetized with chloralose (40 mg/kg) and urethane (400 mg/kg), the effects of electrical stimulation and microinjection of sodium glutamate (0.25 M, 100-200 nl) in the pressor areas in the rostral brain stem on the evoked L5 ventral root response (EVRR) due to intermittent stimulation of sciatic afferents were compared to stimulating the dorsomedial (DM) and ventrolateral (VLM) medulla. In general, stimulating these rostral brain stem pressor areas including the diencephalon (DIC) and rostral pons (RP) produced increases in systemic arterial pressure (SAP). In most of the cases (85%) there were associated changes in the EVRR, predominantly a decrease in EVRR (72%). Stimulation of the midbrain (MB, principally in the periaqueductal grey) produced decreases in SAP and EVRR. Decreases in EVRR was observed in 91% of the DM and VLM stimulations in which an increase in SAP was produced. This EVRR inhibition was essentially unaltered after acute midcollicular decerebration. Increases in EVRR were also observed and occurred more often in the rostral brain stem than in the medulla. Since changes of both EVRR and SAP could be reproduced by microinjection of Glu into the cardiovascular-reactive areas of the brain stem, this suggests that neuronal perikarya in these areas are responsible for both actions. On some occasions, Glu induced changes in EVRR but not in SAP. This effect occurred more frequently in the rostral brain stem than in the medulla. The present data suggest that separate neuron population exist in the brain stem for the integration of SAP and spinal reflexes.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

Achalasia associated with esophageal diverticula. Prevalence and potential implications.

Although esophageal diverticula have been rarely reported in patients with achalasia, their prevalence and the potential implications of the relationship are not well known. We reviewed the medical records and the manometric and radiographic examinations in 120 patients with achalasia to determine the prevalence of esophageal diverticula and to evaluate their importance in this motility disorder. Esophageal diverticula were found in only 6 (5%) of 120 patients, and all were located in the lower half of the esophagus. Sex distribution and the prevalence of dysphagia and regurgitation, which affected all patients with diverticula and 88% of those with achalasia only, were not different significantly. Patients with esophageal diverticula were significantly older (72 vs. 52 years) than those without diverticula. In 5 of 6 patients with diverticula, mean lower esophageal sphincter (LES) pressure was 44.5 mm Hg compared to 39.1 mm Hg in 86 of 114 patients with achalasia only. Treatment by pneumatic dilatation was done in 4 patients with esophageal diverticula and in 105 patients without diverticula. Five esophageal perforations occurred, all in patients without esophageal diverticula.

Adolescent↗
PubMed1994

The changes of ocular axial length and corneal curvatures after scleral buckling for retinal detachment.

As myopia plays an important role in the pathogenesis of retinal detachment, alterations of refractive components after scleral buckling procedures for retinal detachment may be an important factor for retinal redetachment. To find out the refractive change following retinal detachment surgery, we prospectively followed up the alterations of corneal curvature, and axial components (axial length, anterior chamber depth, lens thickness, and vitreous length) of 44 eyes of rhegmatogenous retinal detachment before and after operations. The procedures consisted of encircling scleral buckling (12 eyes) and segmental scleral buckling (32 eyes). All patients were followed for 6 months postoperatively. The corneal curvatures were measured with a keratometer, the axial length and axial components were measured with an A-scan ultrasonography. The methods and materials used in operation were recorded in detail to correlate with the refractive changes. The corneal curvature showed a trend to flatten early after operation (the 1st week), and gradually reversed to steepening. But, the difference was statistically significant only at the K2 (vertical meridian) in the 1st postoperative week and the K1 (horizontal meridian) in the 4th postoperative week. Lengthening of eyeballs were noted in the encircling group (12 eyes), but only the elongation in the 1st postoperative week was statistically significant. While in segmental buckling group, the axial length of the eyeballs was transiently shortened. The shortening was significant in the 2nd, 4th, and 6th week after operation. The reduction of eyeball's axial length was related to the shortening of vitreous length and shallowing of anterior chamber.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1993

Achalasia associated with hiatal hernia: prevalence and potential implications.

Although hiatal hernia is reported with a 40-50% frequency in the general population, its occurrence and potential implications in achalasia are less well known. We reviewed the medical records and radiographic examinations of 120 patients with achalasia to assess the prevalence of hiatal hernia and its importance in evaluation and management of this motility disorder. Hiatal hernia was present in only 10 (8.3%) patients. Age, sex distribution, prevalence of dysphagia and regurgitation, and lower esophageal sphincter pressure measured manometrically were not significantly different in patients having hiatal hernia compared to those without hernia. Most patients (88%) underwent pneumatic dilatation and five esophageal perforations occurred, but all in patients without hiatal hernia. In conclusion, hiatal hernia is uncommon in patients with achalasia for reasons not known. Age, sex, symptoms, and results of esophageal manometry were not significantly different in those with hiatal hernia. Finally, the presence of hiatal hernia is not a contraindication to treatment of achalasia by pneumatic dilatation.

Adolescent↗
PubMed1993

The anatomic basis and clinical applications of flaps based on the posterior tibial vessels.

The vascular anatomy of the posterior tibial vessels has been studied in 20 legs of 10 cadavers. The number, size and distribution of the direct cutaneous and direct muscle branches of the posterior tibial vessels were recorded. For analysis, the leg was divided into four equal segments, Zone I being the most distal and Zone IV the most proximal. The direct cutaneous branches were found to cluster mainly around Zone II. The direct muscle branches to the soleus and flexor digitorum longus muscles arose chiefly in Zones II and III. Based on this knowledge, we performed fasciocutaneous, island soleus muscle, musculo-fasciocutaneous and flexor digitorum longus muscle flaps based on the posterior tibial vessels in 12 patients. Four were free fasciocutaneous flaps and eight were pedicled flaps. All flaps survived and there were no major complications. Delayed wound healing was encountered in three patients.

Adult↗
PubMed1993

Effects of insulin on the cardiovascular integrating mechanisms of brain stem in cats.

In 65 cats anesthetized with alpha-chloralose and urethane, the effects of insulin on cardiovascular responses to stimulation of various structures in the brain stem were studied. The threshold dose of insulin injected intravenously that produced systemic hypoglycemia was 5-10 U/kg. Subthreshold hypoglycemic doses of insulin were used intracerebroventricularly (0.25 U/kg) or intracerebrally (2 mU in 200 nl). Sixty minutes after intravenous insulin, when serum glucose concentrations decreased from 158 to 43 mg/100 ml, pressor responses to stimulation of the periaqueductal gray of midbrain (PAG), locus coeruleus (LC), dorsal medulla (DM), ventrolateral medulla (VLM), and parvocellular reticular nucleus (PVC) decreased significantly. Depressor and bradycardiac response to stimulation of paramedian reticular nucleus or dorsal motor nucleus of vagus (DMV) decreased significantly as well. Thirty minutes after intracerebroventricular insulin, pressor responses of PAG, DM, and the bradycardiac response of DMV decreased significantly. Thirty minutes after intracerebral insulin, pressor responses and renal nerve activities of LC (but not PAG), VLM, DM, and PVC decreased significantly. A similar but faster onset (5 min) of depression of cardiovascular responses on stimulating the LC, VLM, DM, and PVC was observed in another six acutely midcollicular-decerebrate cats recovered from halothane anesthesia. These findings suggest that insulin directly inhibits the vasomotor structures of the brain stem and decreases the pressor responses to stimulation.

Animals↗
PubMed1993

Transaxillary endoscopic sympathectomy--a report of experience in 150 patients with palmar hyperhidrosis.

We report our 1-year experience with transaxillary endoscopic sympathectomy in 150 patients with palmar hyperhidrosis (PH). The double-puncture technique of video laparoscopy was used in a transaxillary approach to perform the sympathectomy by either electrocautery (EC; 93.3%) or electroresection (ER; 7.7%). The procedure was successfully completed in 299 operated limbs and required conversion to open surgery in 1 operated limb because of extensive pleural adhesions. The mean operative time of EC was significantly less than that of ER. In a total of 29 procedures, there were three technical complications. Most patients (92.7%) were discharged after an overnight hospital stay. On the seventh postoperative day, the cure rate was 99.3%. During the mean follow-up period of 200.1 days, there was no recurrence in 130 patients. Apparent compensatory hyperhidrosis occurred in 28 patients (21.5%). In conclusion, transaxillary endoscopic sympathectomy offers a simple and effective treatment to patients with PH, resulting in a shorter hospital stay and convalescent period.

Adolescent↗
PubMed1992

Normal 24-hr ambulatory esophageal pH values. Influence of study center, pH electrode, age, and gender.

Although the most sensitive and specific test for diagnosing gastroesophageal reflux disease, normal standards for prolonged esophageal pH monitoring are based on small sample sizes with questions raised about the effects of pH electrode, older age, gender, and methods of data analysis on pH variables. Recently three groups have established normal data bases using similar methodology. Multiple regression and nonparametric analyses showed that the values for the six traditional pH parameters were comparable across study centers. Therefore, the groups were combined for a total study population of 110 healthy subjects (47 men, 63 women, mean age 38 years with a range of 20-84 years). Further nonparametric analyses revealed the following: (1) type of pH electrode (antimony vs glass) is not significantly related to parameters of physiologic acid reflux; (2) age is not independently related to pH parameters; (3) men tend to have more physiologic reflux than women; and (4) older men tend to experience longer episodes of reflux than younger men and women. There was a significant effect of gender and a significant interaction between age and gender on the number of episodes greater than 5 min (P = 0.008). Nearly significant differences were found for percentage of total acid exposure time (P = 0.03), total reflux episodes (P = 0.02), and the longest reflux episode (P = 0.02). We believe these normal esophageal pH values can be used confidently as standards in any laboratory, and consideration should be given to developing separate standards for men and women.

Adult↗
PubMed1992

Randomized, double-blind, placebo-controlled crossover trial of pirenzepine in patients with gastroesophageal reflux.

A muscarinic receptor subtype 1 (M1) antagonist, pirenzepine, recently has been shown to be relatively free of the usual anticholinergic side effects on esophageal smooth muscle and thus has been implicated for the treatment of gastroesophageal reflux disease (GERD). However, the effect of pirenzepine on GERD remains to be defined. Thirteen patients who demonstrated GERD in a baseline 24-hr ambulatory intraesophageal pH monitoring study were randomized in a double-blind crossover fashion to receive pirenzepine and placebo. An ambulatory 24-hr intraesophageal pH monitor was used to assess reduction in reflux (esophageal pH less than 4.0) with respect to position (upright vs supine), to total number of reflux episodes, and to episodes greater than 5 min. A significant effect for pirenzepine was seen for episodes greater than 5 min (t = 2.61, P = 0.023) and a trend towards significance was seen for total (upright and supine positions combined) percent time of reflux (t = 2.13, P = 0.055). Although not statistically significant, pirenzepine consistently showed greater reduction in all parameters of reflux tested. A greater reduction in percent time of reflux in supine vs upright positions (pirenzepine: 58.9% vs 21.4%; placebo: 43.6% vs 7.3%) may be clinically important in prevention of esophageal injury due to reflux in the recumbent position. Pirenzepine may provide a unique alternative for some GERD patients who may be refractory to other therapies of GERD.

Adult↗
PubMed1992

Prevalence of upper gastrointestinal disease in relation to age: radiologic and clinical implications.

Reports of 1126 endoscopies were reviewed to determine the age-related prevalence of upper gastrointestinal (UGI) diseases as a guide to radiologists performing UGI examinations. Results indicate that (1) there were positive findings in 78% of all endoscopic examinations, and thus most symptomatic patients can be expected to have at least one UGI abnormality; (2) many patients with UGI symptoms have two or more reportable disease processes; (3) the prevalence of serious or life-threatening disease, such as cancer or large ulcers, rises steadily with age; and (4) after age 60, approximately 60% of symptomatic patients have a serious UGI disease. Based on these findings, radiologists should not hesitate to make the diagnosis of multiple abnormalities and should expect to diagnose at least one abnormality in most symptomatic patients having an UGI study. Also, because of the high prevalence of serious lesions in the elderly, endoscopy should be considered for the initial examination of an elderly patient if poor physical status would render the radiologic examination difficult or unreliable.

Adolescent↗