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Biomedical subjects

C L Shen

Publications and source records attributed to C L Shen.

At least 19 recordsLinked to original sources
PubMed2006

[Effects of antiviral effects of agents and prognosis of chronic hepatitis B.].

BACKGROUND: To analyze the effects of difference antiviral agents and the effects of the treatments on long-term prognosis. METHODS: Retrospective research method was applied. RESULTS: About 40% of the patients were treated with interferon or lamivudine. After the treatment, in lamivudine group, the negative rate of HBV DNA was the highest. In the interferon group, the sero conversion rates of HBeAg/HBeAb were 22.9%. In the antiviral treatment patients, the disease progression and the occurrence of cirrhosis and liver cancer were much lower than those of the control groups. The mortality of cirrhosis and liver cancer in the HBeAg/HBeAb sero converted group was much lower than that of the group without HBeAg/HBeAb sero conversion groups (P less than 0.05). CONCLUSION: The antiviral effects of interferon and lamivudine were better than those of the other drug groups. The antiviral drugs could relieve the disease progression and reduce the mortality of cirrhosis and liver cancer.

Antiviral Agents↗
PubMed2001

Multiple actinomyces brain abscesses: case report.

A case of multiple cerebral abscesses caused by actinomyces is reported in a 37 year old male with mucoepidermoid carcinoma of the right lung. In conjunction with penicillin, sulfonamide and erythromycin, the patient underwent stereotactic surgery for aspiration of the brain abscesses under (CT). The bacteria, considered to originate from the right lung, were identified from the abscess material obtained at surgery. Using proper therapy to control infection and intracranial pressure is important. A lon g term follow up with frequent computerised tomography evaluation has been conducted and the patient outcome has been successful recovery.

Actinomycosis↗
PubMed2001

The effect of magnitudes and duration of pressure on cerebral cortex in a rat model.

The aim of this biomechanical study was to investigate the pressure-time-damage relationship on the cerebral cortex using a rat model. During brain surgery, additional cortical injuries induced by traction have been an important clinical issue. A total of 84 rats underwent a unilateral craniectomy, and conduction by hydrostatic pressure loading through a modified central venous pressure device with various combinations of magnitudes ranging from 0.5 to 10 cm H2O and duration from 0.5 to 20 minutes was then performed. Histopathological examination has exhibited three patterns of clustered, spotted damaged neurons and undamaged neuron. Two best-fitted exponential curves were derived from the data to establish the damaged, critical and tolerable loadings responsible for the neuron viability. This research provides information to enhance understanding of the additional cortex injuries induced by traction. Furthermore, the results may have implications in providing clinical guidance and/or development of alarm systems for minimising cortical damage during surgery.

Animals↗
PubMed2001

Interactions of selenium compounds with other antioxidants in DNA damage and apoptosis in human normal keratinocytes.

Selenite (SeL) or selenomethionine (SeM) are the most common selenium (Se) compounds taken as dietary antioxidants to reduce oxidative stress. Because the public may frequently supplement Se compounds at high doses, the possible pro-oxidant effect of Se becomes a concern. SeL and SeM have entirely different pharmacokinetic effects based on dose-related cytotoxicity. Our laboratory has shown previously that high doses of SeL resulted in cytotoxicity and induction of 8-hydroxydeoxyguanosine (8-OHdG) in DNA of primary human keratinocytes (NHK), compared with those treated with the same doses of SEM: Besides Se compounds, other dietary antioxidants, such as vitamin (Vit) C or Vit E, are often supplemented and taken together with Se compounds. However, the cellular effects of these interactions of Se with antioxidants are still unknown. In addition, copper is commonly present in drinking water, food, soil, or the environment to increase the possibility of subchronic toxicity. Copper has been shown to inhibit SeL-induced cytotoxicity and apoptosis in human colonic carcinoma cells. The present study was designed to investigate the interactive effects of SeL or SeM plus Vit C, trolox (a water-soluble Vit E), or copper sulfate (CuSO(4)) on cell viability and induction of 8-OHdG adduct formation in DNA of NHK. NHK cells were treated with no Se, SeL (126.6 microM Se), or SeM (316.6 microM Se) plus two doses each of Vit C (2.27 and 4.45 microM), trolox (40 and 80 microM), or CuSO(4) (7.85 and 15.7 microM) for 24 h. Coincubation of Vit C or CuSO(4) with SeL appeared to protect NHK against SeL-induced cytotoxicity. However, synergistic effects were observed between SeL and trolox resulting in enhanced cytotoxicity. On the other hand, SeM + Vit C, SeM + trolox, and SeM + CuSO(4) did not affect cell viability. In the absence of Se supplementation, Vit C, trolox, or CuSO(4) alone did not induce 8-OHdG adduct formation, regardless of dose. When NHK cells were coincubated with SeL (126.6 microM Se) and Vit C or CuSO(4), they protected NHK from SeL-induced DNA damage with a reduction in 8-OHdG generation. In contrast, treatment of SeL + trolox elevated generation of 8-OHDG: Furthermore, treatments of SeM plus trolox or CuSO(4) elevated 8-OHdG adduct formation. In terms of apoptosis measured as internucleosomal DNA fragmentation, copper protected NHK against SeL-induced apoptosis in cultured NHK. These data suggest that the use of CuSO(4) may play a protective role in SeL-induced cytotoxicity, DNA oxidative damage, and apoptosis and that there may be potentially deleterious interactions among common high-dose antioxidant supplements taken by the public.

Antidotes↗
PubMed2000

Changes in conduction, blood flow, histology, and neurological status following acute nerve-stretch injury induced by femoral lengthening.

The effects of an acute stretch on evoked potential, blood flow, histological change, and clinical neurological state were studied in a rat model of acute nerve stretch induced by femoral lengthening. The purposes of this study were to assess, in a model of acute limb lengthening, the safe limits of nerve stretch for nerve function, the pathogenesis of nerve dysfunction, the sensitivity of spinal somatosensory evoked potential, and one of the proposed criteria for irreversible compromise of the sciatic nerve. Thirty-two rats were assigned to one of four groups defined by the degree of acute femoral lengthening (8, 16, 24, and 32%). Spinal somatosensory evoked potential at L5/6 following stimulation of the sciatic nerve was recorded before, immediately after, and 30 minutes after lengthening. Sciatic nerve blood flow was measured by laser Doppler flowmetry at the stretched site before and after lengthening. One week after the operation and without further lengthening, clinical neurological status was evaluated by the functional index of the sciatic nerve and histological examination was performed. At the measurement immediately after the procedure, amplitude changed significantly in all groups except for the group with 8% lengthening. In all groups, sciatic nerve blood flow also dropped significantly compared with values for the control side. Moreover, a greater percentage increase in acute lengthening corresponded with more marked changes in spinal somatosensory evoked potential and sciatic nerve blood flow. The groups that underwent acute lengthening of 24 and 32% had significant neurological deficits and histological changes and demonstrated a significant and profound (50%) drop in amplitude and blood flow. We concluded that spinal somatosensory evoked potential is very sensitive and may serve as an effective tool for the early detection of impending acute nerve-stretch injury and that a 50% reduction in amplitude indicates irreversible damage.

Acute Disease↗
PubMed2000

Arrhythmias during spinal anesthesia for Cesarean section.

PURPOSE: Spinal block has long been considered a safe anesthesia technique for surgery. However, severe bradycardia, cardiac arrest, and other arrhythmias during spinal anesthesia have been reported and the incidence of intraoperative arrhythmias is not well established. In this study the incidence of arrhythmias during spinal anesthesia was determined. METHODS: We studied 254 healthy women undergoing Cesarean section under spinal anesthesia prospectively. Spinal anesthesia with 10 mg bupivacaine mixed with 0.2 mg morphine was performed at the L3-4 interspace. Intraoperative arrhythmias were recorded and verified later by a cardiologist. RESULTS: First degree atrioventricular block developed in nine patients (3.5%), second degree atrioventricular block in nine (3.5%), severe bradycardia (heart rate < 50 beats x min(-1)) in seventeen (6.7%), multiple VPC in three (1.2%). The height and weight of patients with severe bradycardia, multiple VPCs, or atrioventricular block were not different from those of the other patients. However, the age of patients in the potentially dangerous arrhythmias group was greater than that in the other group (P = 0.006). CONCLUSION: The incidence of arrhythmias as well as hypotension during spinal anesthesia for Cesarean section was higher than expected. Although most of these arrhythmias were transient and recovered spontaneously, they might unexpectedly occur and sometimes need immediate and prompt treatment. It is necessary to remain vigilant during spinal anesthesia for Cesarean section and careful monitoring of these patients is warranted, especially in older parturients.

Adolescent↗
PubMed2000

Free anterolateral thigh flap for reconstruction of head and neck defects following cancer ablation.

Thirty-seven consecutive free anterolateral thigh flaps in 36 patients were transferred for reconstruction of head and neck defects following cancer ablation between January of 1997 and June of 1998. The success rate was 97 percent (36 of 37), with one flap lost due to a twisted perforator. The anatomic variations and length of the vascular pedicle were investigated to obtain better knowledge of anatomy and to avoid several surgical pitfalls when it is used for head and neck reconstruction. The cutaneous perforators were always found and presented as musculocutaneous or septocutaneous perforators in this series of 37 anterolateral thigh flaps. They were classified into four types according to the perforator derivation and the direction in which it traversed the vastus lateralis muscle. In type I, vertical musculocutaneous perforators from the descending branch of the lateral circumflex femoral artery were found in 56.8 percent of cases (21 of 37), and they were 4.83 +/- 2.04 cm in length. In type II, horizontal musculocutaneous perforators from the transverse branch of the lateral circumflex femoral artery were found in 27.0 percent of cases (10 of 37), and they were 6.77 +/- 3.48 cm in length. In type III, vertical septocutaneous perforators from the descending branch of the lateral circumflex femoral artery were found in 10.8 percent of cases (4 of 37), and they were 3.60 +/- 1.47 cm in length. In type IV, horizontal septocutaneous perforators from the transverse branch of the lateral circumflex femoral artery were found in 5.4 percent of cases (2 of 37). They were 7.75 +/- 1.06 cm in length. The average length of vascular pedicle was 12.01 +/- 1.50 cm, and the arterial diameter was around 2.0 to 2.5 mm; two accompanying veins varied from 1.8 to 3.0 mm and were suitable for anastomosis with the neck vessels. Reconstruction of one-layer defect, external skin or intraoral lining, was carried out in 18 cases, through-and-through defect in 17 cases, and composite mandibular defect in two cases. With increasing knowledge of anatomy and refinements of surgical technique, the anterolateral thigh flap can be harvested safely to reconstruct complicated defects of head and neck following cancer ablation with only minimal donor-site morbidity.

Adult↗
PubMed1999

Differential expression of beta-amyloid precursor and Bcl-2 proto-oncogene proteins in the developing dog retina.

Previous studies of rat retinas have not only provided evidence that beta-amyloid precursor (APP) and B-cell lymphoma proto-oncogene (Bcl-2) proteins are colocalized in retinal Müller glial cells, but have also indicated that common mechanisms regulate their expression in these cells (Chen, S.T., Garey, L.J., Jen, L.S., 1994. Bcl-2 proto-oncogene protein immunoreactivity in normally developing and axotomised rat retinas. Neurosci. Lett. 172, 11 14; Chen, S.T., Gentleman, S.M., Garey, L.J., Jen, L.S., 1996. Distribution of beta-amyloid precursor and B-cell lymphoma proto-oncogene proteins in the rat retina after optic nerve transection or vascular lesion. J. Neuropathol. Exp. Neurol. 55, 1073-1082; Chen, S.T., Garey, L.J., Jen, L.S., 1997. Expression of beta-amyloid precursor protein immunoreactivity in the retina of the rat during normal development and after neonatal optic tract lesion. NeuroReport 8, 713-717). This investigation attempts to resolve whether or not the pattern observed in rats also applies to other higher mammalian species by examining the expression of immunoreactivity to APP and Bcl-2 in developing as well as mature dog retinas using immunocytochemical methods. Experimental results indicate that the immunoreactivity of both APP and Bcl-2 is located primarily in the inner retina, particularly in the ganglion cells and their axons in late fetal and neonatal stages. From the second postnatal week (the time of eye opening) onwards, immunoreactivity to APP, but not Bcl-2, is localized primarily in the endfeet and proximal part of the radial process of retinal Müller glial cells. Although the findings show both APP and Bcl-2 are expressed in ganglion cells and their processes suggest that the molecules have a role in the differentiation of neurons in the central nervous tissue, the lack of Bcl-2 in the Müller glial cells in dog retinas further suggests that the two molecules may have different biological roles with respect to glial function.

Amyloid beta-Protein Precursor↗
PubMed1999

NADPH-diaphorase activity in normally developing and intracranially transplanted retinas.

The activity and distribution of nicotinamide dinucleotide phosphate diaphorase (NADPH-d), an enzyme that is widely distributed in the central nervous system and involved in the production of the free radical nitric oxide, were investigated histochemically in the normal developing and intracranially transplanted retinas. In the normal rat retina, NADPH-d activity was first detected in cells in the ganglion cells layer (GCL) and blood vessels on the first postnatal day (P0). A small but distinct population of NADPH-d positive cells were observed along the inner border of the inner nuclear layer at P7. NADPH-d positive sublaminae began to appear in the inner plexiform layer during the second postnatal week, and several strongly reactive sublaminae resembling those observed in the adult were observed by the fourth postnatal week. The overall spatio- temporal sequence of development of NADPH-d positive cells in the transplanted retina was similar to that of the normal retina, except a lack of reactive in the inner plexiform layer in more mature transplants as compared with normal retinas of corresponding ages. These results indicate that the time course of development and distribution of NADPH-d cells in early postnatal retina requires signals mainly of intraretinal origin and is independent of influence from the surroundings. While this finding is supportive to the notion that neurons that are rich in NADPH-d are resistant to injury or perturbation, the observation of a lack of well organized NADPH-d reactive sublaminae in the inner plexiform layer in older transplants suggests a possible alteration in the synaptic circuitry in the inner retina with increasing postgrafting survival time.

Animals↗
PubMed1999

The influence of delay and the effect of fibrin sealant on the cut surface of the peripheral nerve. An experimental study in the rat.

Thirty-two sciatic nerves in 16 rats were divided to investigate the effect of delay in fixation and the use of fibrin sealant at the site of the division on the nerve end. Specimens were assessed by morphological and morphometric criteria using scanning electron microscopy and longitudinal sections. All specimens showed a protruded nerve end. Wrapping the nerve with fibrin sealant before division and immediate fixation of the specimen resulted in less protrusion.

Animals↗
PubMed1999

Delayed akathisia and suicidal attempts following epidural droperidol infusion--a case report.

Epidural administration of droperidol has been used to prevent postoperative nausea and vomiting (PONV) caused by opioids, but the adverse reactions were relatively neglected. We present a patient who received patient-controlled epidural analgesia (PCEA) with bupivacaine-morphine-droperidol mixture for one and half days following hemorrhoidectomy, developed paroxysmal adverse reactions of akathisia, dysphoria, and suicidal attempts 3 days after the initiation of the treatment. The use of droperidol in PCEA for prevention of nausea and vomiting therefore needs to be re-evaluated according to the serious side effects occurring in our case.

Akathisia, Drug-Induced↗
PubMed1998

Neuropeptide innervation and neuroendocrine cells in allergic rhinitis and chronic hypertrophic rhinitis.

BACKGROUND: The neuropeptides and neuroendocrine cells are proven to exist in the human nasal mucosa. However, the pathophysiological and neuroimmunological roles of regulatory peptides in human nasal diseases require further investigation. OBJECTIVES: To investigate and compare the functional morphology and quantify the tissue concentration of regulatory peptides in the nasal mucosas of normal, allergic rhinitis (AR) and chronic hypertrophic rhinitis (CHR) subjects. METHODS: Human inferior turbinate mucosa specimens from 28 patients with AR, 25 patients with CHR and 15 patients without any nasal diseases were investigated. Using immunohistochemistry and radioimmunoassays, we detected the presence, distribution and concentrations of various neuropeptides (vasoactive intestinal peptides [VIP], neuropeptide Y [NPY], substance P [SP], calcitonin gene-related peptides [CGRP]) and general neuroendocrine markers (neurone-specific enolase, chromogranin A and somatostatin). Quantitative analysis of the stained fibres and cells were performed using a graphic AutoCAD program. RESULTS: The presence and distribution of NPY, CGRP, and SP nerve fibres and neuroendocrine cells were similar among the three subject groups. AR subjects had significantly higher VIP and SP tissue concentrations. VIP fibres had highest density in AR subjects and these fibers predominantly innervated vessels. In CHR, VIP fibres primarily innervated glands. CONCLUSIONS: VIP and SP may play an important neuroimmunological role in the pathogenesis of AR. VIP may lead to the hypertrophic changes of submucosal glands in the pathogenesis of CHR.

Calcitonin Gene-Related Peptide↗
PubMed1998

Distribution and quantity of neuroendocrine markers in allergic rhinitis.

Neuroendocrine components exist in the human nasal mucosa. However, the pathophysiological and neuroimmunological roles of the regulatory peptides in allergic rhinitis (AR) require further investigation. To analyse the functional morphology and quantify the tissue concentration of regulatory peptides in the nasal mucosa of AR subjects, human inferior turbinate mucosa specimens from 25 patients with AR, 20 patients with non-allergic rhinitis and 10 patients without any nasal diseases were investigated. Using immunohistochemistry and radioimmunoassays, we detected the presence, distribution and concentrations of various neuropeptides [vasoactive intestinal peptide (VIP), neuropeptide Y (NPY), substance P (SP) and calcitonin gene-related peptide (CGRP)] and general neuroendocrine markers (neuron-specific enolase and chromogranin A). Quantitative analysis of the stained fibres and cells was performed using a graphic AutoCAD program. The presence and distribution of NPY, CGRP and SP nerve fibres and neuroendocrine cells were similar among the three subject groups. AR subjects had significantly higher tissue concentrations of VIP and SP. AR subjects had increased numbers of VIP fibres which predominantly innervated vessels. Thus, VIP and SP play important neuroimmunological roles in the pathogenesis of AR.

Biomarkers↗
PubMed1998

Feeding of a well-cooked beef diet containing a high heterocyclic amine content enhances colon and stomach carcinogenesis in 1,2-dimethylhydrazine-treated rats.

Epidemiologic studies have linked the consumption of red meat and the consumption of highly browned meats containing high levels of heterocyclic aromatic amines (HCAs) to increased risk of colorectal cancer or polyps. The present study determined the effects of long-term feeding of beef-containing diets with low and high levels of HCAs (in the context of a low or high beef tallow diet) on a standard 1,2-dimethylhydrazine (DMH)-induced colon tumorigenesis protocol. Very lean beef was cooked by a variety of methods at different temperatures, and the levels of the major HCAs (2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline, 2-amino-3,4,8-trimethylimidazo[4,5-f]quinoxaline, and 2-amino-1-methyl-6-phenylimidazo[4,5-f]pyridine) were measured by high-performance liquid chromatography. Diets incorporating beef containing low or high levels of HCAs were fed for 12 weeks, during which DMH was administered to induce colon tumors, followed by various dietary regimens as promotional stimuli. Feeding of a beef diet high in HCAs resulted in more DMH-induced colon adenocarcinomas, but only in the context of a low-fat diet. The high-HCA diets increased stomach tumors in all DMH-treated rats. An apparent interaction of high HCA with a high fat level reduced the colon tumor incidence and tumor numbers in those diets containing both factors. These results support the epidemiologic data linking well-cooked meat to increased risk for colon and stomach cancer, but the role of dietary fat level remains puzzling.

1,2-Dimethylhydrazine↗
PubMed1998

Absence of PhIP adducts, p53 and Apc mutations, in rats fed a cooked beef diet containing a high level of heterocyclic amines.

Meat cooked at high temperatures contains mutagens and carcinogens known as heterocyclic amines (HCA). Cooking temperature and time determine the amount of HCA produced. The present study examined the DNA of liver, colon, and stomach from rats fed a high level of HCA for 27 weeks. Male Sprague-Dawley rats were fed a high-fat AIN-76A-based diet containing 60% by weight cooked beef containing a high level of HCA, especially 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP, 72 ng/g cooked beef), the most abundant HCA in cooked meat products. At the end of 27 weeks the rats were terminated, and small portions of liver, colon, and stomach were quick-frozen in liquid nitrogen. The DNA was isolated from the thawed tissue by phenol-chloroform extraction, and the genomic DNA was analyzed for the presence of PhIP adducts by 32P-postla-beling analysis. The DNA was also used in polymerase chain reactions to amplify the rat p53 and Apc genes, then direct dye-terminator DNA sequencing was carried out. Results showed no PhIP adducts in any tissue. In addition, no signature p53 or Apc gene mutations were seen in colon or stomach DNA. These results indicate that the high level of HCA present in a diet of well-cooked meat does not cause 1) persistent PhIP adducts similar to those produced by feeding pure PhIP at high doses or 2) p53 and Apc gene mutations in nontumor tissue.

Animals↗
PubMed1997

Dietary lipids modulate bone prostaglandin E2 production, insulin-like growth factor-I concentration and formation rate in chicks.

This study examined the effects of dietary fat on the fatty acid composition of liver and bone, and on the concentration of insulin-like growth factor-I (IGF-I) in liver and bone, as well as the relationship of these factors to bone metabolism. Day-old male broiler chicks were given a semipurified diet containing one of four lipid sources: soybean oil (SBO), butter+corn oil (BC), margarine+corn oil (MAC), or menhaden oil+corn oil (MEC) at 70 g/kg of the diet. At 21 and 42 d of age, chicks fed MEC had the highest concentration of (n-3) fatty acids [20:5(n-3), 22:5(n-3) and 22:6(n-3)] in polar and neutral lipids of cortical bone but the lowest amount of 20:4(n-6) in polar lipids. Diets containing t-18:1 fatty acids (MAC and BC) resulted in t18:1 accumulation in bone and liver. Bone IGF-I concentration increased from 21 to 42 d in chicks given the SBO and BC diets. Tibial periosteal bone formation rate (BFR) was higher in chicks given BC compared with those consuming SBO and MEC at 21 d. The higher BFR and concentrations of hexosamine in serum and IGF-I in cartilage, but lower 20:4(n-6) content in bone polar lipids in chicks given BC compared with those given SBO suggest that BC optimized bone formation by altering the production of bone growth factors. A second study confirmed that dietary butter fat lowered ex vivo prostaglandin E2 production and increased trabecular BFR in chick tibia. These studies showed that dietary fat altered BFR perhaps by controlling the production of local regulatory factors in bone.

Animals↗
PubMed1997

Neuropeptidergic innervation of human nasal mucosa in various pathological conditions.

This study aims to investigate the roles of neuropeptides in the pathophysiology of human nasal diseases. By using immunohistochemistry and radioimmunoassay, we detected the presence, distribution and concentrations of the following neuropeptides in human nasal tissue: vasoactive intestinal peptides (VIP), neuropeptide Y (NPY), substance P (SP), and calcitonin gene-related peptides (CGRP). This was performed in human nasal inferior turbinate mucosa from 20 patients with allergic rhinitis, twenty-five patients with chronic hypertrophic rhinitis and 10 patients without any nasal disease conditions. The presence and distribution of NPY. CGRP and SP fibers among the three subject groups displayed no evident differences. VIP fibers were densely stained around the vessels in the allergic group. In contrast, these fibers were more prominently distributed around the submucosal glands of the chronic hypertrophic rhinitis group. The concentration of VIP and SP in human nasal inferior turbinate showed a significant increase in allergic subjects. Thus, VIP may be revelant to the hypertrophic changes of the nasal mucosa. Both SP and VIP may play significant neuroimmunological roles in the pathogenesis of allergic rhinitis.

Calcitonin Gene-Related Peptide↗