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Biomedical subjects

J Dai

Publications and source records attributed to J Dai.

At least 145 records · Page 8Linked to original sources

[Surgical therapy of hallux valgus in the young and middle-aged female].

OBJECTIVE: To correct hallux valgus in the young or middle-aged female. METHOD: Through dissecting foot specimens with hallux valgus we found that the intrinsic factor that caused hallux valgus was a "capstan" like mechanism of pressure. In order to eliminate the mechanism of the deformity, we cut off the link between the adductoris hallucis and the hallux completely. The tendon of adductoris hallucis was sutured to the fascial flap of hallucis bursa passing through a hole in the caput of the metatarsus. By this way the adductoris hallucis was fixed to the 1st metatarsus strongly, thus it pulled the 1st metatarsus directly. RESULTS: Twenty feet received this operation. 18 feet were followed up for 0.5-4 years. The rate of excellent and good results was 100%. CONCLUSION: This operation by suturing the adductoris hallucis with the fascial flap of the hallucis bursa not only can relieve pain but also restore the normal appearance of the foot.

Adult↗

[Imaging findings of primary sarcoma in the kidney].

OBJECTIVE: To reveal the characteristic findings of primary sarcoma of the kidney. METHODS: From December 1988 through February 1996, seven cases of renal sarcoma confirmed by histo-pathology were retrospectively reviewed, including 3 leiomyosarcoma and 1 for each of liposarcoma, fibrosarcoma, malignant fibrous histiocytoma and malignant Schwannoma. Image material: CT in 6 cases, ultrasonography in 6 cases and MRI in 1 case. RESULTS: The tumor was located in renal parenchyma in 6 cases and in renal pelvis in 1 case. On the images, it was commonly a large mass with irregular margin, indefinite, circumscribed and heterogeneous in density with necrosis inside as observed on the CT scan and 2 cases with median to hyperattenuation on the enhanced CT scan; 4/6 cases gave median heterogeneous mixed echo and 2/6 cases appeared as even hypoechoic mass on the ultrasonogram. On MRI, the mass gave isosignal intensity on T1WI and increased signal intensity with moderate heterogeneity was seen on T2WI or became more enhanced and heterogeneous but no more than renal parenchyma on the enhanced T1WI of MRI. Big tumor thrombus in the inferior vena cava and renal vein was noted in the fibrosarcoma. CONCLUSIONS: Primary renal sarcomas give imaging findings characteristic of malignant tumor but without histological specificity and can not be differentiated from renal cell carcinoma. The enhanced CT and MRI capable of providing useful information of the localization, changes in density/signal and extent of invasion of the tumor, are beneficial to the differential diagnosis and managements.

Adolescent↗

[Clinical diagnostic standard of mediopatellar plica syndrome].

OBJECTIVE: To increase the level of clinical diagnosis of mediopatellar plica syndrome. METHOD: We reviewed the preoperative clinical symptoms of 67 knee joints that were proved to have pathologic mediopatellar plica by arthroscopy. RESULT: Mediopatellar plica syndrome had the following clinical symptoms: painful knee and mediopatellar tenderness in all patients; tender bands in 56.7% patients; positive test of flexion or extension with internal femoral condyle pressed in 62.7% patients; positive Mcmarry's sign in 31.3% patients. CONCLUSION: The clinical diagnostic standard of mediopatellar plica syndrome is that the first above-mentioned clinical symptom plus one of other three symptoms could suggest the diagnosis, while the first clinical symptom plus two or three of other three symptoms could define the diagnosis.

Adult↗

Ultrastructural observation on spermatocytogenesis in Taeniid cestodes.

AIM: To study the spermatocytogenesis of taeniid cestodes at the ultrastructural leaves. METHODS: Transmission electron microscopy. RESULTS: The ultrastructural observation on spermatocytogenesis in Taenia solium, T. saginata and T. pisiformis were made by TEM. Two types of spermatogonia; type A and B, as well as the supporting cells surrounding the peripheral of spermatogonia are recognized. The type A spermatogonia are stem cells and the type B are mother cells which produce 16 primary spermatocytes by mitosis for 4 times with the cells unseparated. The primary spermatocytes are characterized by the ribosome masses in the cytoplasm. 32 secondary spermatocytes arranged in roselike were produced by reductive division of primary spermatocytes. The secondary spermatocytes become the spermatid quickly by short time development. CONCLUSION: The dividing mode of spermatogonia in Taeniid cestodes is mitosis with cells unseparated.

Animals↗

Ultrastructural observation on the transformation of the spermatozoon in spermatogenesis of Taeniid cestodes.

AIM: To study the transformation of taeniid spermatozoon during spermatogenesis on the ultrastructure level. METHODS: Transmission electronmicroscopy. RESULTS: This paper was the second part of the ultrastructural observations on the spermatogenesis in Taeniid cestodes: The transformation of the spermatozoon. The 64-spermatid-plasmodium was generated from the secondary meiosis of the 32 rose-like secondary spermatocytes. The transformation of the spermatozoon was a complex process. Firstly, both the cytoplasm and nucleus of the spermatid elongated while the cytoplasm increased and connected to the cytoplasmic mass (cytophore). Secondly, the chromatins of nucleus polymerized to a thread-bundle-like structure. Finally, it detached from the cytoplasm mass and became a mature spermatozoon. The mature spermatozoon was a thread-like structure, about 16.2-18.6 microns in length and 0.35-0.45 micron in diameter. There were two structurally distinct parts: the part with the nucleus was the head and the part without the nucleus was the tail. The head measured about 5-6 microns in length, 1/3 of the total body length and contained an elongated nucleus which twined around the axoneme without mitochondria. The tail was about 11.2-16.6 microns in length. Throughout the core of the tail was an axoneme with typical "9 + 1" structure. The anterior of the tail, just behind the head, were some mitochondria, about 1.6-1.7 microns in total length which twined around the axoneme. The posterior of the tail contained only an axoneme. In cross-section of the spermatozoon, about 46 microtubules were beneath the plasma membrane. CONCLUSION: The transformation of the spermatozoon is a very complex process.

Animals↗

[Immunodiagnosis of cysticercosis by simplified western blotting using recombinant fusion protein as antigen].

AIM: To provide simple and useful method for the immunodiagnosis of cysticercosis. METHODS: Fusion protein of beta-galactosidase-Cysticercus cellulosae cDNA was analysed with simplified Western blot. RESULTS: The positive rate was 93.5% when detecting 124 cases of human cysticercosis sera with four clones (cC1, cC2, cP1 and cH1) and 100% when detecting 38 cases of porcine cysticercosis sera with three clones (cC1, cC2 and cP1), being higher than those using monoclone fusion protein alone. Moreover, the fusion proteins did not react with other parasitosis sera. CONCLUSION: Simplified Western blot analysis using recombinant fusion protein as antigen was highly sensitive and specific and easy to be operated.

Animals↗

Distribution of vasopressin and vasoactive intestinal polypeptide (VIP) fibers in the human hypothalamus with special emphasis on suprachiasmatic nucleus efferent projections.

The human suprachiasmatic nucleus (SCN) is located in the basal part of the anterior hypothalamus and is considered as the biological clock that generates circadian rhythms and synchronizes the daily activity pattern with the environmental light-dark cycle. However, the mechanisms and pathways by which the SCN transmits its information to the other brain areas are unknown. Therefore, in the present study, we investigated the efferent projections of the SCN by the immunocytochemical staining of two major peptidergic SCN neurotransmitters: vasopressin (VP) and vasoactive intestinal polypeptide (VIP). It confirmed that these peptides are present in different subdivisions of the SCN. The results of this investigation show that VP and VIP fibers arising from the SCN were detected to branch extensively and hence seem to innervate the SCN itself and the central and medial part of the anteroventral hypothalamic area (AVH), the area below the paraventricular nucleus (sub-PVN), the ventral part of the paraventricular nucleus (PVN), and the dorsomedial nucleus of the hypothalamus (DMH). There appeared to be substantial congruity between the presumptive human SCN projections and those as observed by tracing in rat or hamster. Regarding the anatomical organization of the human SCN projections, the main projection areas appeared to be the AVH, the sub-PVN, the ventral part of the PVN, and the DMH. The observation that VIP and in particular VP fibers pass between the SCN and the PVN suggests that the human SCN and the PVN may have a direct anatomical connection. In addition, VP and VIP fibers were detected in several other hypothalamic areas that are not known to have clear direct connections to the SCN. The possible origin of these VP and VIP fibers is discussed.

Dorsomedial Hypothalamic Nucleus↗

At physiological pH, d(CCG)15 forms a hairpin containing protonated cytosines and a distorted helix.

To investigate potential structures of d(CGG/CCG)n that might relate to their biological function and association with triplet repeat expansion diseases (TREDs), the structure of a single-stranded (ss) oligonucleotide containing d(CCG)15 [ss(CCG)15] was examined by studies of the pH and temperature dependence of electrophoretic mobility, UV absorbance, circular dichroism, chemical modification, and P1 nuclease digestion. ss(CCG)15 had an unusually high pKa (7.7 +/- 0.2). At pH 8.5, ss(CCG)15 formed a relatively unstable (Tm = 30 degrees C in 1 mM Na+) hairpin containing CpG base-pair steps. At pH 7.5, the hairpin contained protonated cytosines but no detectable C x +C base pairs, increased thermal stability (Tm = 37 degrees C), increased stacking of the CpG base-pair steps, and a single cytosine that was flipped away from the central portion of the helix. Examination of ss(CCG)18 and ss(CCG)20, which were designed to adopt hairpins containing alternative GpC base-pair steps, revealed hairpins containing CpG base-pair steps, pKas of approximately 8.2 and approximately 8.4, respectively, and distorted helices. The results suggest that DNA sequences containing (CCG)(n > or = 15) adopt hairpin conformations that contain CpG rather than GpC base-pair steps; the mismatched cytosines are protonated at physiological pH but are not H-bonded. We propose that protonation arises from the stacking of two cytosines in the minor groove of a distorted helix.

Base Sequence↗

Transcutaneous bilirubinometry: its role in the assessment of neonatal jaundice.

OBJECTIVE: To review the literature on transcutaneous bilirubinometry so that its exact role in the prevention of kernicterus or bilirubin encephalopathy could be determined. DESIGN AND METHODS: Literature searches were done in Medline and Current Contents. RESULTS: It is estimated that about 50% of newborns have an episode of jaundice in the first few days of life. Six percent of newborns may develop hyperbilirubinemia (> 220 mumol/L), which can potentially cause bilirubin encephalopathy or kernicterus, a severe neonatal disease. In the past, serum bilirubin (SB) has been the preferred method of detecting hyperbilirubinemia in newborns. The ordering of SB in neonates is based on visual evaluation by either physicians or nursing staff. Skin puncture collection of blood exposes the neonate to trauma and risk of infection. A noninvasive device for predicting serum bilirubin levels in newborns diminishes the need to do skin punctures. One such device that has been very extensively studied is the Minolta AirShields Jaundice Meter. It is a portable light-weight instrument that uses reflectance measurements on the skin to determine the amount of yellow color present in the skin, namely transcutaneous bilirubin (TcB). Although the TcB measurements correlate well with serum bilirubin (SB) levels, they cannot accurately predict serum bilirubin because of error related to a variety of factors. CONCLUSIONS: TcB cannot be used directly to make decisions about transfusions or phototherapy in neonates. It is a good tool for screening neonates to determine when a laboratory measurement of serum bilirubin is needed. Such a practice requires careful selection of the decision level so that false-negative TcB values do not prevent appropriate serum bilirubin tests from being done.

Bilirubin↗

HPCE methods for the identification and quantitation of antibodies, their conjugates and complexes.

We review here much of the existing literature that deals with analysis, resolution, characterization, and (at times) quantitation of antibodies in capillary electrophoresis modes. Each major mode of CE shown applicable to antibody analysis is described, along with the major applications of that mode for antibodies. Discussions are presented as to the mechanisms of antibody resolution in CE, interactions of various buffer components with the proteins leading to resolution, and methods of quantitation for antibodies. The literature is critically reviewed with regard to true application of CE for antibody analysis, limitations, information possible, information implied, and which samples have actually been assayed by CE modes. The literature is critically reviewed up to and including 1996, both for the scientific and commercial literature, especially vendor applications and real world applications possible.

Animals↗

The role of endothelial nitric oxide synthase in the pathogenesis of a rat model of hepatopulmonary syndrome.

BACKGROUND & AIMS: The hepatopulmonary syndrome occurs when intrapulmonary vasodilatation causes impaired arterial gas exchange in liver disease. The pathogenesis is poorly understood, although nitric oxide may be involved. Common bile duct ligation in the rat is a model of the hepatopulmonary syndrome, but no studies have evaluated NO in pulmonary vasodilatation in this model. The aim of this study was to determine whether NO contributes to intrapulmonary vasodilatation after bile duct ligation. METHODS: Endothelial and inducible NO synthase (NOS) levels and localization and NO activity in pulmonary artery rings were assessed after bile duct ligation. RESULTS: Pulmonary endothelial NOS levels increased and alveolar vascular staining was enhanced after bile duct ligation. No change in pulmonary inducible NOS levels or localization was detected. Increased endothelial NOS levels correlated with alterations in gas exchange and were accompanied by enhanced NO activity and a blunted response to phenylephrine, reversible by NOS inhibition, in pulmonary artery rings. Portal-vein-ligated animals, which do not develop intrapulmonary vasodilatation, had no changes in pulmonary NOS production or in NO activity in pulmonary artery rings. CONCLUSIONS: NO, derived from pulmonary vascular endothelial NOS, contributes to intrapulmonary vasodilation in animal hepatopulmonary syndrome.

Acetylcholine↗

The secretion-coupled endocytosis correlates with membrane tension changes in RBL 2H3 cells.

Stimulated secretion in endocrine cells and neuronal synapses causes a rise in endocytosis rates to recover the added membrane. The endocytic process involves the mechanical deformation of the membrane to produce an invagination. Studies of osmotic swelling effects on endocytosis indicate that the increased surface tension is tightly correlated to a significant decrease of endocytosis. When rat basophilic leukemia (RBL) cells are stimulated to secrete, there is a dramatic drop in the membrane tension and only small changes in membrane bending stiffness. Neither the shape change that normally accompanies secretion nor the binding of ligand without secretion causes a drop in tension. Further, tension decreases within 6 s, preceding shape change and measurable changes in endocytosis. After secretion stops, tension recovers. On the basis of these results we suggest that the physical parameter of membrane tension is a major regulator of endocytic rate in RBL cells. Low tensions would stimulate endocytosis and high tensions would stall the endocytic machinery.

Animals↗

Expression of thrombin receptors in human atherosclerotic coronary arteries leads to an exaggerated vasoconstrictory response in vitro.

Alpha-thrombin can alter vascular tone by proteolytic cleavage of its cell-surface receptor, which exposes a tethered peptide sequence, Ser-Phe-Leu-Leu-Arg-Asn (SFLLRN) that activates the receptor. We investigated the effects of increasing severity of coronary atherosclerosis on SFLLRN-induced responses on 165 human coronary artery rings isolated fresh from 15 patients who underwent cardiac transplantation. In 40 coronary rings with minimal intimal proliferation, addition of 0.001-5 microM SFLLRN resulted in a dose- and endothelium-dependent relaxation reaching a maximum of -87.0 +/- 2.3% (mean +/- SEM) and median inhibitory concentration (IC50) of 0.1 microM. Increasing severity of atherosclerotic lesion, as determined by morphometric quantification of intimal thickening under light microscopy, resulted in graded decreases in both sensitivity and magnitude of the observed relaxation. The maximal relaxations in coronary arteries with mild and moderate intimal proliferation were -76.7 +/- 3.5% (mean +/- SEM of 41 rings) and -63.6 +/- 6.4% (mean +/- SEM of 22 rings), respectively. In the 21 coronary rings with severe intimal proliferation, no significant SFLLRN-induced relaxation was noted. Mechanical disruption of intimal endothelium abolished the SFLLRN-induced relaxation observed in the minimal to mild intimally thickened arteries, whereas in arteries with moderate and severe intimal thickening, a significant SFLLRN-induced contraction (19 +/- 10% and 43 +/- 7%, respectively) was observed. Similar endothelium-dependent relaxations in minimal atherosclerotic and endothelium-independent contraction in severe atherosclerotic coronary arteries were also observed with alpha-thrombin. These findings confirm a recent in situ hybridization and immunohistochemistry study reporting localization of cloned thrombin receptors only in endothelium of "normal appearing" human abdominal aortae and induced expression of thrombin receptors in intimal/medial regions of the atherosclerotic vessels and further demonstrate that similar expression of thrombin receptors in human atherosclerotic coronary arteries leads to an unmasking of a marked vasoconstrictory response.

Adolescent↗

False-positive EMIT II opiates from ofloxacin.

The cross-reactivities of four quinolone antibiotics--ofloxacin, norfloxacin, ciprofloxacin, and nalidixic acid--toward the EMIT II Opiates enzyme immunoassay were examined. Drug-free urine was spiked with the individual drugs up to 5,000 mg/L. Only ofloxacin showed potential for causing a false-positive opiates immunoassay screening result (apparent morphine > 300 micrograms/L). The method produced a positive opiate result at an ofloxacin concentration of 200 mg/L, a 0.16% cross-reactivity. Three hospitalized patients taking therapeutic doses of ofloxacin all gave false-positive EMIT II Opiates urine screening results. Three patients taking norfloxacin and three patients taking ciprofloxacin gave true-negative urine screening results. False-positive results were also obtained from the urines of two volunteers who each consumed a single 400-mg ofloxacin pill.

Anti-Infective Agents↗

Loss of cytoskeletal support is not sufficient for anoxic plasma membrane disruption in renal cells.

The goal of this study was to determine whether anoxic membrane disruption is initiated by loss of cytoskeletal support in rabbit renal proximal tubules (PT). We specifically tested 1) whether cytoskeletal perturbation affects membrane integrity under normoxia, 2) whether cytoskeletal perturbation potentiates anoxic membrane damage, and 3) whether the membrane protection by glycine depends on cytoskeletal integrity. Cytoskeletal perturbation was achieved with 10 microM cytochalasin D (CD) because it selectively disturbs F-actin organization and has similar effects as anoxia on the cytoskeleton of PT. During normoxia, CD caused decreased basal F-actin content, microvillar breakdown, and membrane-cytoskeleton dissociation, as revealed by the use of laser tweezers. However, membrane integrity was not altered by CD, as monitored by lactate dehydrogenase release. CD pretreatment of PT did not potentiate anoxic membrane damage. Finally, plasma membrane protection by glycine during anoxia remained in CD-pretreated PT despite loss of cytoskeletal support. These results demonstrate that loss of cytoskeletal support is not sufficient for anoxic plasma membrane disruption.

Animals↗