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Biomedical subjects

J Wan

Publications and source records attributed to J Wan.

At least 37 records · Page 2Linked to original sources
PubMed2000

Thoracoscopic removal of intrathoracic neurogenic tumors: a combined Chinese experience.

OBJECTIVE: To review the surgical and clinical results of minimally invasive resection of intrathoracic neurogenic tumors using a video-assisted thoracoscopic technique. SUMMARY BACKGROUND DATA: Thoracoscopy has emerged as a possible means for diagnosing and managing various intrathoracic disorders. Benign intrathoracic tumors often are ideal lesions for resection using a video-assisted technique. The authors report on their combined experience with the thoracoscopic resection of 143 intrathoracic neurogenic tumors. METHODS: Between March 1992 and February 1999, 143 patients with intrathoracic neurogenic tumors were diagnosed and underwent resection using video-assisted thoracoscopic techniques in three teaching centers. Case selection, surgical technique, and clinical results were reviewed. RESULTS: The average age of the patients was 40.8 years; 57.3% were male. Thirty-eight patients (27%) had symptoms attributable to the masses. Seventy-two masses were neurofibromas, 33 were neurilemmomas, 7 were paragangliomas, and 31 were ganglioneuromas. All but seven tumors were located in the posterior mediastinum. The masses were on average 3.5 cm in greatest diameter. The mean surgical time was 40 minutes, and the average hospital stay was 4.1 days. There were no major postoperative complications or recurrences to date. Nine patients reported paresthesias over the chest wall during a mean follow-up of 29 months. CONCLUSIONS: Resection of intrathoracic neurogenic tumors using a thoracoscopic technique based on standard surgical indications would seem to be appropriate. Most of these masses are benign and readily removed. For dumbbell tumors, a combined thoracic and neurosurgical approach is mandatory.

Adult↗
PubMed2000

The relationship between dysfunctional voiding and congenital vesicoureteral reflux.

Voiding dysfunction may play an etiological role in congenital vesicoureteral reflux in otherwise normal children. There is increasing evidence to suggest that in some infants and older children, vesicoureteral reflux is associated with congenital structural deficiency of the trigonal ureterovesical junction valve mechanism as well as aberrant lower urinary tract function. In the youngest infants this abnormal function can be present at birth, whereas in older children it may be acquired and learned during the toilet training years, if it is not already present. Voiding dysfunction may spontaneously improve or require additional therapy. Increased rates of breakthrough infection, renal scarring and surgical failure have been associated with undiagnosed and untreated lower urinary tract dysfunction, emphasizing the importance of its recognition. Controversy remains regarding the role of invasive urodynamics and anticholinergic medication, and further large-scale prospective studies are necessary before either modality becomes routine when assessing and treating these children.

Age Factors↗
PubMed2000

Effect of polysaccharide krestin on glutathione peroxidase gene expression in mouse peritoneal macrophages.

Polysaccharide krestin (PSK) is a protein-bound polysaccharide extracted from the sporophore Coriolus versicolor. Previously, we found that PSK could reduce the oxidative injury that oxidised low-density lipoprotein (Ox-LDL) produced in monocytes/macrophages, and therefore have some pro-phylactic or therapeutic effect on atherosclerosis. Glutathione peroxidases, including selenium-dependent glutathione peroxidase (SeGPx) and non-selenium-dependent glutathione peroxidase (non-SeGPx, also called glutathione S-transferase [GST]), play an important role in the defence against oxidative injury. In order to find out if the effects of PSK were associated with antioxidant enzymes, we investigated its effect on glutathione peroxidase activity and messenger RNA (mRNA) expression in mouse peritoneal macrophages. Results showed that PSK enhanced SeGPx and non-SeGPx activity, and increased SeGPx and GST-P (pi class GST) mRNA in mouse peritoneal macrophages. In addition, the induction by PSK of the two glutathione peroxidases could be blocked by cycloheximide (30 micrograms/mL), but 5 micrograms/mL actinomycin D and 50 micrograms/mL acetovanilone (a superoxide inhibitor) had no effect. We conclude that PSK improved glutathione peroxidase activity through transcriptional induction of mRNA expression.

Animals↗
PubMed1999

Macrophage colony-stimulating factor reduces tert-butyl hydroperoxide induced oxidative injury to monocytes/macrophages.

The transformation of macrophages into foam cells is an important event in the development of atherosclerosis, and the oxidative injury caused by oxidized low density lipoprotein (Ox-LDL) plays an essential role in that process. It has been proved that macrophage colony-stimulating factor (M-CSF) could prevent the progression of atherosclerosis in Watanabe heritable hypercholesterolemic (WHHL) rabbits. We proposed that the anti-atherogenic effect of M-CSF was partly associated with its protective effect on monocyte-derived macrophages from Ox-LDL induced oxidative injury. In order to prove this, we investigated the effect of M-CSF on the oxidative injury caused by tert-butyl hydroperoxide (tbOOH) to mouse peritoneal macrophages and U937/J774 cell lines. The results showed that M-CSF could protect mouse peritoneal macrophages from oxidative injury (presented by cell morphology and cell survival rate); L929 cell-conditioned medium (L929-CM) had the same effect as M-CSF; and anti-M-CSF monoclonal antibody could mostly block the protective effect of L929-CM on macrophages. L929-CM was proved to be also able to decrease the impact of plasma membrane fluidity in U937 and J774 cells treated with tbOOH. Incubation with tbOOH caused DNA fragmentation in U937 cells. The presence of L929-CM greatly reduced the number of apoptotic U937 cells characterized by DNA fragmentation. From these results, we concluded that M-CSF could protect monocytes/macrophages from oxidative injury. It may be one of the mechanisms which explain the anti-atherogenic effect of exogenous M-CSF in WHHL rabbits.

Animals↗
PubMed1999

Activity-induced potentiation of developing neuromuscular synapses.

Electrical activity plays a critical role in shaping the structure and function of synaptic connections in the nervous system. In Xenopus nerve-muscle cultures, a brief burst of action potentials in the presynaptic neuron induced a persistent potentiation of neuromuscular synapses that exhibit immature synaptic functions. Induction of potentiation required an elevation of postsynaptic Ca2+ and expression of potentiation appeared to involve an increased probability of transmitter secretion from the presynaptic nerve terminal. Thus, activity-dependent persistent synaptic enhancement may reflect properties characteristic of immature synaptic connections, and bursting activity in developing spinal neurons may promote functional maturation of the neuromuscular synapse.

Action Potentials↗
PubMed1999

Concomitant radiation therapy and targeted cisplatin chemotherapy for the treatment of advanced pyriform sinus carcinoma: disease control and preservation of organ function.

BACKGROUND: Squamous cell carcinoma of the pyriform sinus is an unfavorable disease which frequently presents in advanced stages. Despite aggressive "standard treatment" involving debilitating surgery and postoperative radiation therapy treatments, the survival and functional outcome for pyriform sinus carcinoma remains poor. Hence, we reviewed our experience in the management of advanced pyriform sinus carcinoma using "organ preservation" chemoradiation therapy. METHODS: Twenty-five patients diagnosed with stage III/IV pyriform sinus squamous cell carcinoma treated with supradose, intra-arterial targeted cisplatin, and concomitant radiotherapy were analyzed for response rates, survival, pattern of failure, and function of the preserved organs. Our protocol consisted of weekly intra-arterial infusions of cisplatin at 150 mg/m(2) x 4 and concurrent radiation therapy at 1.8 Gy or 2.0 Gy/fraction to a planned total of 68-74 Gy to the primary site/overt nodal disease. RESULTS: Nineteen (76%) of the 25 patients were diagnosed with stage IV disease, 17 of whom were first seen with bulky lymphadenopathy (ie, N2-N3 disease) while 10 had T4 lesions. Twenty-four of 25 patients were evaluable for response assessment. Complete response rates of 92% and 76% were achieved at the primary site and in lymph nodes, respectively. Hence, the overall complete response rate in the neck was 76% (16/21). At a median follow up interval of 42 months (range = 30-58 months), the projected 5-year overall and disease-specific survival using the Kaplan-Meier method are 23% and 50% respectively. No patient has developed recurrence at the primary site and only one patient relapsed regionally, which was surgically salvaged for an "above clavicle" disease control rate of 88% and an organ preservation rate of 88%. Almost 90% of the patients have achieved a satisfactory voice and 70% are able to swallow at 12 months postcompletion of therapy. CONCLUSION: Our chemoradiation protocol is as effective as other treatment modalities for patients with advanced pyriform sinus carcinoma while maintaining organ preservation and function in the majority of the patients.

Aged↗
PubMed1999

VLPP in the evaluation of the female with stress urinary incontinence.

The Valsalva leak-point pressure has become an important urodynamic test in the evaluation of incontinent women. A review of the history of the test, its methodology, and variables that can influence its performance is presented. Correlation with clinical findings, reproducibility and comparison with other urodynamic tests are discussed. Although the test is still evolving and several major variables have been recognized as affecting its results, it remains sound and reliable. It has excellent correlation with the clinical severity of incontinence and a high degree of inter- and intraexaminer reproducibility.

Evaluation Studies as Topic↗
PubMed1999

Contemporary incidence of morbidity related to vesicoureteral reflux.

OBJECTIVES: The association among vesicoureteral reflux (VUR), renal scarring, and reflux nephropathy is well established. Screening programs for children who present with urinary tract infection (UTI) and their siblings, along with medical and surgical management, have been promoted by pediatric medical and urologic specialists in Buffalo and the surrounding community for more than two decades. Has this comprehensive and costly effort resulted in a decrease in VUR-related morbidity and should it be continued? METHODS: The records of all active patients who presented from 1982 through 1997 to this region's single pediatric nephrology referral center were reviewed. One hundred twenty-two children and adolescents (73 boys, 49 girls) were identified with hypertension (HTN), renal insufficiency (RI), and end-stage renal disease (ESRD) requiring dialysis or transplantation. RESULTS: There were 70 patients (57%) with HTN, 19 (16%) with RI, and 33 (27%) with ESRD. Reflux nephropathy was the underlying cause in 6 patients (5%)-3 with HTN and 3 with ESRD. The etiologies of morbidity in the remaining patients were medical renal disease, 61 (50%); idiopathic, 17 (14%); obstructive uropathy, 14 (11%); primary congenital renal hypoplasia, 12 (10%); and vascular, 12 (10%). Of the 6 patients with VUR-related morbidity, 4 were boys (3 with ESRD, 1 with HTN) and 2 were girls (with HTN). Five children presented in the 1980s and 1 in the 1990s. Only 1 patient had a history of UTI, and she presented early in the series in 1982 at 5 years of age. Ages of presentation were infancy (2 boys), early childhood (1 boy, 1 girl), and adolescence (1 boy, 1 girl). Reasons for presentation were failure to thrive (n = 2), voiding dysfunction without UTI (n = 1), muscle cramps (n = 1), UTI (n = 1), and HTN (n = 1). Reflux grade ranged from I to V, but 4 patients had grade III or less. CONCLUSIONS: Awareness of VUR-related morbidity has led to more widespread diagnosis and treatment, which appears to have resulted in a dramatic decrease in the numbers of affected patients in this community. The diagnosis and treatment of VUR has altered the epidemiology of HTN and renal failure in children and young adults.

Adolescent↗
PubMed1999

Differences in responses to 70 dB clicks of cerebellar units with simple versus complex spike activity: (i) in medial and lateral ansiform lobes and flocculus; and (ii) before and after conditioning blink conditioned responses with clicks as conditioned stimuli.

Activity was recorded from 554 cerebellar units in eleven conscious cats to determine if responses to 70 dB clicks differed in units with simple and complex spike discharges. Effects of region of recording and behavioral state (with click used as a conditioned stimulus for conditioning) were also assessed. Cells with only simple spikes were distinguished from cells that had the following types of complex spike events: Type I-simple or initial spike followed > 1 ms by multiple spikes with baseline displacement (classical complex spikes), Type II--followed < or = 1 ms by spikes with or without baseline displacement (spikes in the absolute refractory period should arise from a separate site of initiation), and Type III-followed by spikes and displacement too close to the baseline noise to distinguish as Type I or II. Among the groups mean baseline activity was greatest in cells with Type I complex spikes, least in cells with Type III complex spikes, and greater in Type II cells than simple cells. Significant increases in activity within 32 ms of presenting clicks were found in the groups of Type II cells and simple cells. These appear to be the main auditory responsive cells of the cerebellar regions studied. Activity of Type II cells best reflected the temporal properties of the click; responses of simple cells had slower onsets (except in flocculus) and longer durations. Responses to click in Type II and simple cells differed in recordings from: (i) lateral ansiform lobe (lateral crus I and portions of crus II), (ii) medial ansiform lobe (medial crus I), and (iii) flocculus. The largest mean responses above baseline in the first 32 ms after click were found in Type II cells of the lateral ansiform lobe with onsets of 8-16 ms. Magnitudes of response differed before and after conditioning and backward conditioning. In the lateral ansiform lobe, the < 32 ms response to click was greater in Type II than simple cells in each state, but showed a greater increase above baseline after backward conditioning when conditioned responses were not produced than after conditioning. The onset of increased activity to click conditioned stimuli in Type II cells of the lateral ansiform region preceded the onset of the blink conditioned response after conditioning, consisted almost entirely of simple spikes, and reflected an increase in magnitude of response as opposed to an increased number of responsive units. After conditioning, an increased number of units in the flocculus responded to click conditioned stimuli in the 16-24 ms post stimulus period. Of the 16 cells with an onset of increased activity at this time, eight showed only simple spike activity. Seven of the remaining eight cells (all Type II) showed a significant increase in conditioned stimulus-evoked complex spiking above the low (usually < 1/s) baseline level of complex spike discharges. The findings support the conclusions that cerebellar units can respond rapidly enough to acoustic stimuli to play a role in auditory as well as motor processing and that the responses to 70 dB clicks differ among cells with simple and complex spike discharges. The differences are influenced substantially by the region of cerebellar recording and the behavioral state. The findings in cells of the flocculus offer the first evidence that complex as well as simple spike activity can contribute to an increased probability of discharge to click as a conditioned stimulus after conditioning.

Acoustic Stimulation↗
PubMed1999

[Orbito-zygomatic approach for removal of tumors of the skull base].

OBJECTIVE: To evaluate the advantages and indications of orbito-zygomatic approach for removal of tumors of the skull base. METHODS: Fifteen patients with tumors of the skull base were operated on using obito-zygomatic approach. The advantages and indications of the approach were evaluated. RESULTS: In 7 cases of meningioma, total removal of the tumor was achieved in 6 cases, and subtotal removal in 1. In 4 cases of craniopharyngioma, the tumor were totally removed in 3 cases, and subtotally removed in 1. The tumor were totally removed in 2 cases of trigerminal neurilemoma and 1 case of germinoma. There was one operative death. All patients recovered except 3 who had minor extraocular parasis. CONCLUSIONS: This approach ensures additional space, and less cerebral retraction for easy access to skull base tumor, especially the large neoplasm of middle cranial base with or without orbital or posterior cranial base extension.

Adolescent↗
PubMed1998

Cloning and characterization of the CYP2D1-binding protein, retinol dehydrogenase.

A CYP2D1-binding protein, 29 k-protein (p29), has been isolated and its N-terminal amino acid sequence has been reported (Ohishi et al. (1993) Biochim. Biophys. Acta 1158, 227-236). In this study, p29 cDNA was isolated by PCR with oligonucleotide probes designed from the N-terminal amino acid sequence and p29 was found to be a microsomal retinol dehydrogenase, a member of the short-chain alcohol dehydrogenase family which metabolize hydroxysteroids and prostaglandins. CYP2D1 and p29 were expressed in Saccharomyces cerevisiae to characterize these proteins. CYP2D1 had an absorption maximum at 448 nm in a CO-reduced form. Expressed p29 in yeast cells was detected with anti-p29 antibody. Solubilized CYP2D1 and p29 from yeast microsomes were mixed and applied to an anti-CYP2D1 antibody-binding column. Both proteins were retained in the column and eluted with glycine buffer (pH 2.8). However, when applied alone, p29 was not retained in the column. The findings indicated that CYP2D1 bound tightly with p29. Catalytic activities of p29 expressed in yeast were investigated. p29 had retinal reductase activity in the presence of NADPH. Addition of CYP2D1 and NADPH-P450 reductase increased the retinal reductase activity of p29. These findings suggest that the complex of CYP2D1, p29, and NADPH-P450 reductase has an important role in the metabolism of retinoids.

Alcohol Oxidoreductases↗
PubMed1998

Oxidized cholesterol in oxidized low density lipoprotein may be responsible for the inhibition of LPS-induced nitric oxide production in macrophages.

Previous work has shown that oxidized low density lipoprotein (Ox-LDL) inhibited lipopolysacchride (LPS)-induced nitric oxide (NO) production in macrophages. In this paper, the role of different components of Ox-LDL in the inhibitory effect was studied by measuring nitrite in media. Ox-LDL inhibited LPS-induced NO production in macrophage cell line J774.A1. When compared with Ox-LDL, native and acetylated LDL had a lesser effect on NO production. Pre-clearance of lipid hydroperoxides (LOOH) in Ox-LDL and removal of soluble thiobarbituric acid reactive substances (TBARS) in Ox-LDL solution by dialysis had no influence on the inhibitory effect of Ox-LDL. The protein moiety of Ox-LDL had no effect on NO production, but the lipid moiety inhibited NO production to about the same extent as intact Ox-LDL. Linoleic acid and phosphatidylcholine, the main components of LDL lipid, whether oxidized separately or together, had no effect on NO production. However, if linoleic acid and cholesterol oxidized together, there was very strong inhibition of NO production. Cholesterol oxidized alone also had some inhibitory effect. These results suggest that oxidized cholesterol in Ox-LDL might be responsible for the inhibition of NO production in macrophages.

Animals↗
PubMed1998

Renal growth characteristics in children born with multicystic dysplastic kidneys.

OBJECTIVES: To report on the growth characteristics of the affected and contralateral kidneys in children born with multicystic dysplastic kidneys (MCDKs). METHODS: Thirty-three patients were enrolled from 1970 to 1995: 23 were initially managed nonoperatively (mean follow-up 3.39 years), and 10 underwent nephrectomy. Patients underwent radionuclide renal imaging and contrast voiding cystography. Serial ultrasonography was used to obtain measurements of the affected and contralateral kidneys. Blood pressure measurements and serum creatinine levels were available in some patients. RESULTS: Among the 23 nonoperative patients, the affected MCDK involuted in 4 patients during a mean follow-up of 4.5 years at a rate of 1.02 cm/yr (24% annually); 7 kidneys decreased in size at a mean rate of 0.38 cm/yr (5.8% annually); 6 grew at a mean rate of 1.16 cm/yr (9.9% annually); 1 kidney did not change in size; and 5 children were lost to follow-up. The mean size of the contralateral kidneys at birth was 5.3 cm, 2 standard deviations larger than normal. Over time, this relative hypertrophy was maintained at a growth rate of 0.89 cm/yr (18.5% annually). Two patients who had undergone nephrectomy also had serial postoperative ultrasonic renal measurements, and contralateral growth was 0.61 cm/yr (12.16% annually). All but 1 patient had normal blood pressure measurements and serum creatinine levels. CONCLUSIONS: Most MCDKs involute or decrease in size over time, although this may take many years. Contralateral hypertrophy is seen at birth and is maintained during childhood growth, regardless of whether the affected kidney is removed. There is no associated hypertension or malignancy when the dysplastic kidney is left in place.

Follow-Up Studies↗
PubMed1998

The effect of essential oils of basil on the growth of Aeromonas hydrophila and Pseudomonas fluorescens.

Basil essential oils, including basil sweet linalool (BSL) and basil methyl chavicol (BMC), were screened for antimicrobial activity against a range of Gram-positive and Gram-negative bacteria, yeasts and moulds using an agar well diffusion method. Both essential oils showed antimicrobial activity against most of the micro-organisms examined except Clostridium sporogenes, Flavimonas oryzihabitans, and three species of Pseudomonas. The minimum inhibitory concentration (MIC) of BMC against Aeromonas hydrophila and Pseudomonas fluorescens in TSYE broth (as determined using an indirect impedance method) was 0.125 and 2% (v/v), respectively; the former was not greatly affected by the increase of challenge inoculum from 10(3) to 10(6) cfu ml-1. Results with resting cells demonstrated that BMC was bactericidal to both Aer. hydrophila and Ps. fluorescens. The growth of Aer. hydrophila in filter-sterilized lettuce extract was completely inhibited by 0.1% (v/v) BMC whereas that of Ps. fluorescens was not significantly affected by 1% (v/v) BMC. In addition, the effectiveness of washing fresh lettuce with 0.1 or 1% (v/v) BMC on survival of natural microbial flora was comparable with that effected by 125 ppm chlorine.

Acyclic Monoterpenes↗
PubMed1998

The synergistic preservative effects of the essential oils of sweet basil (Ocimum basilicum L.) against acid-tolerant food microflora.

Essential oils extracted by hydrodistillation from five different varieties of Ocimum basilicum L. plants (Anise, Bush, Cinnamon, Dark Opal and a commercial sample of dried basil) were examined for antimicrobial activity against a wide range of foodborne Gram-positive and -negative bacteria, yeasts and moulds by an agar well diffusion method. All five essential oils of basil showed antimicrobial activity against most of the organisms tested with the exception of Flavimonas oryzihabitans and Pseudomonas species. The inhibitory effect of Anise oil, in comparison with mixtures of the predominant components of pure linalool and methyl chavicol, against the acid-tolerant organisms, Lactobacillus curvatus and Saccharomyces cerevisiae, was examined in broth by an indirect impedance method. Synergistic effects between Anise oil, low pH (pH 4.2) and salt (5% NaCl) were determined. The antimicrobial effect of Anise oil was also assessed in a tomato juice medium by direct viable count, showing that the growth of Lact. curvatus and S. cerevisiae was completely inhibited by 0.1% and 1% Anise oil, respectively. The results of the current study indicate the need for further investigations to understand the antimicrobial effects of basil oils in the presence of other food ingredients and preservation parameters.

Acyclic Monoterpenes↗