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Biomedical subjects

T S Tang

Publications and source records attributed to T S Tang.

At least 19 recordsLinked to original sources
PubMed2001

A direct high-performance liquid chromatographic method for the determination of therminol 66 contamination in commercial glycerin and fatty acids.

A simple and sensitive high-performance liquid chromatographic method for the determination of Therminol 66 thermal heating fluid in glycerin and fatty acids is developed. Sample solutions dissolved in methanol-tetrahydrofuran (50:50, v/v) are injected directly into a reversed-phase C18 column and eluted with a methanol and water mixture (88:12, v/v). The concentration of the thermal heating fluid is monitored by fluorescence detection at 257 nm (excitation) and 320 nm (emission). The calibration graph obtained from various concentrations of the thermal heating fluid in the methanol and tetrahydrofuran mixture is linear (correlation coefficient = 0.999), and the limit of detection is 0.01 microg/mL. Spiked glycerin containing 0.1 to 1.0 microg/g of the thermal heating fluid also gives good linearity with a mean recovery of 95.3%. The mean intra- and interassay precision are 1.80-6.51% and 5.71-9.03%, respectively, at the 0.1-microg/g level. The method is simple and does not require any pretreatment step, thus it is ideal for quality assurance purposes.

Journal Article↗
PubMed2001

A comparison of blacks and whites seeking treatment for chronic pain.

OBJECTIVE: Most conceptualizations of chronic pain acknowledge the importance of culture and social circumstances. Cultural and social influences may differ for persons of different racial or ethnic groups, and this circumstance may lead them to experience and adjust differently to pain. The current study compared adjustment to chronic pain by blacks and whites seeking treatment for chronic pain. SUBJECTS AND MEASURES: Fifty-seven black and 207 white patients completed measures of anxiety, depression, disability, pain, and physical symptoms during their initial visit to a university pain clinic. RESULTS: Comparisons showed that the groups did not differ with regard to age, sex, education, chronicity of pain, pain location, work status, previous surgeries, medical diagnosis, medication, wage replacement, or involvement in litigation. However, the black group reported higher pain severity, more avoidance of activity, more fearful thinking, more physical symptoms, and greater physical and psychosocial disability. The groups remained significantly different with regard to avoidance, fearful thinking, and physical symptoms after pain severity was statistically controlled for; however, they did not remain different on disability. CONCLUSIONS: These results show that blacks and whites with chronic pain experience pain differently. Several factors may underlie these differences, including family situation, health care experiences, or other unmeasured behavioral, environmental, or social influences. Other investigators should attempt to replicate these findings and more closely examine variables that may explain them.

Adaptation, Psychological↗
PubMed2000

Xenopus and chicken sperm contain a cytosolic soluble protein factor which can trigger calcium oscillations in mouse eggs.

There is evidence showing that at fertilization the sperm introduces into egg cytoplasm a protein-based cytosolic factor, which serves as the physiological trigger for inducing Ca(2+) oscillations in mammalian eggs. Here we show that sperm of nonmammalian vertebrates also contain a cytosolic protein factor that can induce Ca(2+) oscillations when introduced into mammalian eggs. We have observed that cytosolic extracts derived from Xenopus or chicken sperm could induce mouse eggs to undergo Ca(2+) oscillations similar to those induced by bovine sperm extracts. The factor responsible for inducing Ca(2+) oscillations was of high molecular weight and heat- or proteinase K-labile. We show that 0.5 chicken sperm-equivalents or 1-2 Xenopus sperm-equivalents of the extracts had enough activity to trigger Ca(2+) oscillations in mouse eggs. Our findings illustrate that although Xenopus, chicken, and mammals are evolutionarily divergent species, the function of the sperm protein factor in triggering Ca(2+) oscillations in mammalian eggs appears not to be species specific in vertebrates.

Animals↗
PubMed2000

Cultural barriers to mammography, clinical breast exam, and breast self-exam among Chinese-American women 60 and older.

BACKGROUND: This study examined screening utilization at least once and regular adherence to mammography, clinical breast exam, and breast self-exam among older Chinese-American women. METHOD: One hundred women were recruited from senior centers in two metropolitan cities. Participants completed a questionnaire that included sections on demographics, health history, health insurance coverage, breast cancer screening, common and cultural barriers to screening, and acculturation. RESULTS: Logistic regression models found insurance coverage for mammography and acculturation to be significant predictors of having had a mammogram at least once. Low perceived need/lack of physician recommendation and recency of physical examination were significant predictors of having had a mammogram in the past year. Acculturation and modesty were significant predictors of having had a clinical breast exam at least once, while recency of physical examination was a significant predictor of having had a clinical breast exam in the past year. Reliance on medial professionals for screening and forgetting were significant predictors of having performed breast self-exam at least once, and forgetting was a significant predictor of regular performance of breast self-exam. CONCLUSIONS: These findings suggest that both common and cultural barriers play a role in breast cancer screening among older Chinese-American women, with cultural factors being more influential in the initiation of cancer screening behavior.

Acculturation↗
PubMed2000

Ca(2+) oscillations induced by a cytosolic sperm protein factor are mediated by a maternal machinery that functions only once in mammalian eggs.

At fertilization in mammals, the sperm activates the egg by inducing a series of oscillations in the intracellular free Ca(2+) concentration. There is evidence showing that this oscillatory event is triggered by a sperm-derived protein factor which diffuses into egg cytoplasm after gamete membrane fusion. At present the identity of this factor and its precise mechanism of action is unknown. Here, we studied the specificity of action of the sperm factor in triggering Ca(2+) oscillations in mammalian eggs. In doing so, we examined the patterns of Ca(2+) signaling in mouse eggs, zygotes, parthenogenetic eggs and maturing oocytes following the stimulation of bovine sperm extracts which contain the sperm factor. It is observed that the sperm factor could induce Ca(2+) oscillations in metaphase eggs, maturing oocytes and parthenogenetically activated eggs but not in the zygotes. We present evidence that Ca(2+) oscillations induced by the sperm factor require a maternal machinery. This machinery functions only once in mammalian oocytes and eggs, and is inactivated by sperm-derived components but not by parthenogenetic activation. In addition, it is found that neither InsP(3) receptor sensitivity to InsP(3) nor Ca(2+) pool size are the determinants that cause the fertilized egg to lose its ability to generate sperm-factor-induced Ca(2+) oscillations at metaphase. In conclusion, our study suggests that the orderly sequence of Ca(2+) oscillations in mammalian eggs at fertilization is critically dependent upon the presence of a functional maternal machinery that determines whether the sperm-factor-induced Ca(2+) oscillations can persist.

Animals↗
PubMed2000

[Germ cell apoptosis and regulation in testis].

Both spontaneous and induced germ cell apoptosis occur during the process of germ cell differentiation in testis, which is an important mechanism to remove surplus and abnormal germ cells. It has been known that germ cell apoptosis is under the control of endocrine, cell social association and gene. To elucidate the molecular mechanisms by which germ cell apoptosis is regulated and the elements of the death machinery will provide a basis for effective management of male infertility as well as more targeted approaches to male contraception.

Animals↗
PubMed2000

[Pituitary adenylate cyclase activating polypeptide ameliorates the damage and inhibits the increase of intracellular calcium concentration in cultured hippocampal neurons induced by glutamate].

Hippocampal neurons cultured from 7 to 9 d in vitro were used to observe the effect of glutamate. Treatment of glutamate for 24 h greatly decreased neuronal survival and pretreatment with pituitary adenylate cyclase activating polypeptide (PACAP) significantly attenuated hippocampal neuron death induced by glutamate. Moreover, glutamate dose-dependently increased the intracellular calcium concentration in cultured hippocampal neurons, while PACAP inhibited the increase of intracellular calcium concentration induced by glutamate. PACAP 6-38, a specific PACAP type I receptor antagonist, completely inhibited the amelioration of glutamate induced death and the decrease of intracellular calcium concentration induced by PACAP in cultured hippocampal neurons. The data suggest that PACAP has a neuroprotective effect on the hippocampal neuronal damage induced by glutamate, which is related to an inhibition of glutamate-induced increase of intracellular calcium concentration and mediated by PACAP type I receptor.

Animals↗
PubMed1999

Cloning of novel temperature-related expressed sequence tags in rat testis during spermatogenesis.

Spermatogenesis needs the relatively cool environment of the scrotum in most mammals, it would be arrested when the testis was exposed to abdominal temperature. In this study, we have used a differential display PCR technique (DD-PCR) to screen temperature-related ESTs during spermatogenesis (TRS) in scrotal testes through a unilateral cryptorchid rat model after in situ analysis of testis cell DNA fragmentation. We reported here the cloning and sequencing of three such ESTs: TRS1, TRS3, and TRS4. Northern blot analysis confirmed that they were expressed specifically in scrotal testes. In situ hybridization showed that TRS1 was mainly expressed in the spermatocytes and the round spermatids in scrotal testis. Homology searches revealed that TRS1 and TRS3 were unknown cDNA sequences, and TRS4 was identical to a known EST whose function had not been reported. TRS1, TRS2, and TRS3 were first found to be temperature-related during spermatogenesis.

Animals↗
PubMed1999

The role of cultural variables in breast self-examination and cervical cancer screening behavior in young Asian women living in the United States.

This study examined cultural factors as predictors of breast self-examination (BSE) and participation in cervical cancer screening in young Asian and Caucasian women in the United States. Comparisons between Asian and Caucasian samples revealed significant differences in ever performing BSE and obtaining a pap test; the Caucasian women reported higher participation in both behaviors. Factor analysis of cultural barriers to screening revealed four factors: communication with mother, openness around sexuality, prevention orientation, and utilization of Western medicine. Logistic regression predicting BSE performance from demographics, acculturation, and cultural barriers revealed openness around sexuality to be a significant predictor. Pap test participation was predicted by year in college, ever having engaged in sexual intercourse, prevention orientation, and global acculturation. Cultural factors should be considered in programs to enhance participation in cancer screening.

Adult↗
PubMed1999

An examination of antecedent traumas and psychiatric comorbidity among male inmates with PTSD.

Despite substantially higher rates of posttraumatic stress disorder (PTSD) among male inmates than among men in the general population, there is a dearth of research on PTSD among incarcerated men. The current study addresses traumatic events that precede PTSD and psychiatric disorders that are comorbid with PTSD in an inmate sample. Seeing someone seriously injured or killed, being sexually abused, and being physically assaulted were the three most commonly reported antecedent traumas to PTSD. Lifetime and current rates of mood disorders, anxiety disorders, and antisocial personality disorder were elevated among inmates with a diagnosis of PTSD. Two hundred and thirteen inmates participated in the study. Sixty-nine participants (33%) met lifetime DSM-III-R criteria for PTSD, and 45 (21%) met current criteria. The findings are compared with general population samples, and implications of the findings are discussed.

Adult↗
PubMed1999

The anatomy of the extrathoracic intercostobrachial nerve.

BACKGROUND: In the past decade surgeons have become increasingly aware of the morbidity caused by the division of the intercostobrachial nerve (ICBN) during axillary dissection. To prevent this problem and also to explain its variable occurrence, a detailed knowledge of the anatomy of the nerve is required. METHODS: Twenty-eight axillary dissections were performed demonstrating the anatomy of the ICBN. RESULTS: In all dissections the nerve originated from the second intercostal space, with contributions from the first and third intercostal nerve each on one occasion. The posterior axillary branch was constant but may branch early, simulating a second nerve. The ICBN had a variable relationship to the lateral thoracic vein: anterior, posterior or wrapping around it. In 36% there was a connection to the medial cord of the brachial plexus in the axilla. In the upper arm the nerve lies in the subcutaneous fat; in the majority it supplied at least the proximal half of the arm, and in one-third it reached the level of the elbow joint. In 18% there was a connection to the medial cutaneous nerve of the arm. CONCLUSION: The ICBN and its main branch (the posterior axillary nerve) were constant in all dissections. But its origin, size, connection to the brachial plexus and medial cutaneous nerve of the arm were variable, as was its ultimate destination in the arm.

Arm↗
PubMed1998

Spontaneous and fertilization-induced Ca2+ oscillations in mouse immature germinal vesicle-stage oocytes.

Mouse germinal vesicle (GV)-stage oocytes not only show Ca2+ oscillations in response to fertilization but also exhibit spontaneous Ca2+ oscillations during meiotic maturation in vitro. Spontaneous Ca2+ oscillations were entirely suppressed by microinjection of heparin (25 microM final intracellular concentration), an antagonist of inositol trisphosphate (IP3) receptor, whereas fertilization-induced Ca2+ oscillations were only partially inhibited by heparin even at a high dosage of 600 microM. Inhibition of endogenous IP3 generation by antagonizing phospholipase C using U73122 (20 microM final concentration) also failed to suppress the generation of fertilization-induced Ca2+ transients, suggesting that the two types of Ca2+ oscillations do not have the same dependence on IP3-induced Ca2+ release. In addition, spontaneous Ca2+ oscillations require the presence of intact GV whereas fertilization-induced Ca2+ oscillations are independent of the GV but require cytoplasm, since enucleation eliminated only spontaneous Ca2+ oscillations but not fertilization-induced Ca2+ oscillations. These results suggest that IP3-induced Ca2+ release is the primary mechanism responsible for spontaneous Ca2+ oscillations. Sperm-induced Ca2+ oscillations, however, may employ more complex mechanisms during fertilization.

Animals↗
PubMed1993

[Analysis of 112 cases of pedicular screw placement].

This article presented 464 pedicular screw placement in 112 patients who were treated with a method of internal spinal fixation system. Radiographic films or CT scans were used to assess the accuracy of the screw insertion into the vertebral body through pedicle and the angle of inserted screw to the end plate of the vertebral body. Results revealed that 88.7% of screw placement were considered excellent and good, 11.3% were acceptable and poor. There was no neurological complication at all. It is concluded that preoperative radiographic films in prone position to determine the point of entry and accurate marking of the pedicle were required for pedicular screw placement even without roentgenoscopic monitoring during operation. The indications and techniques were discussed.

Adult↗
PubMed1993

Transient myeloproliferative disorder in a Down's neonate with rearranged T-cell receptor beta gene and evidence of in vivo maturation demonstrated by dual-colour flow cytometric DNA ploidy analysis.

Neonates with Down's syndrome may develop a transient myeloproliferative disorder (TMPD) which on presentation is indistinguishable from acute leukemia, with the difference manifest only on follow-up. The clinical course is one of spontaneous remission in TMPD and relentless progression in leukemia. We describe a Down's neonate presenting with hyperleucocytosis and circulating blasts which were positive for CD34, myeloid (CD33), megakaryocytic (CD41, CD42b, CD61), and T-lineage (CD3, CD7), but not B-lineage, associated antigens. Clonal rearrangement of the T-cell receptor beta (TCR beta) gene was found, with the immunoglobulin heavy chain gene in germline configuration, showing the disease to be a clonal proliferation of a multipotential stem cell involving the myeloid and T lineages. Dual-colour flow cytometric DNA ploidy analysis of CD41 positive blasts showed initially a predominant 2N population, but polyploidization to 6N and 8N cells was found on follow-up, concomitant with a progressive decrease in circulating blasts, suggesting maturation of the abnormal clone and a provisional diagnosis of TMPD. This was shown by the eventual resumption of normal haemopoiesis with the disappearance of blasts and the clonally rearranged TCR beta gene.

Bone Marrow↗
PubMed1993

Hook-pin and compression screw in the treatment of femoral neck fractures. Clinical trial and biomechanical study.

One hundred and two patients with femoral neck fracture underwent combined hook-pin and compression screw fixation. Eighty-five patients were followed up for over 6 months. The fracture was united in 80 patients. The advantages of this method included less trauma, simple technique and firm internal fixation and early postoperative partial weight-bearing. Biomechanical study showed that this method is superior to Smith-Petersen nailing and two hook-pins methods. The sliding and continuous compression of this method promotes impaction and healing of the fracture.

Adolescent↗
PubMed1989

Haemorrhagic shock encephalopathy.

Three children suffered from acute onset of convulsions and progressive coma associated with hyperpyrexia, profound shock and generalized bleeding tendency. No causative agent could be identified. Despite aggressive resuscitation they all died. Post-mortem examination revealed cerebral oedema, petechial haemorrhages of the gut, lungs and kidneys, and a generalized depletion of lymphocytes in the lymphoid organs. Features were compatible with haemorrhagic shock encephalopathy, which is a highly fatal disease. The possible role of hyperpyrexia in its pathophysiology is discussed. More careful case identification and research in various possible aetiological factors may help elucidate its pathogenesis.

Brain↗